Cross section

横截面
  • 文章类型: Journal Article
    这项工作分析了两名老年患者主动脉内的血流动力学现象及其对血流行为的影响,特别受其中之一的血管内假体影响(患者II)。计算流体动力学(CFD)被用于这项研究,涉及速度的测量,压力,和在第三心动周期的各个时间点的壁剪切应力(WSS),在胸主动脉的两个横截面内的特定位置。第一个横截面(横截面1,CS1)位于初始流体分叉之前,就在右锁骨下动脉前.第二横截面(横截面2,CS2)位于紧接在左锁骨下动脉之后。结果表明,在常规主动脉几何结构下,速度和压力大小遵循流体动力学原理,显示变化。然而,在病人II,CS2附近的内置假体和内置假体的近端边界由于脉动流动而显着破坏了流体行为。患者I的横截面积小于患者II的横截面积,导致更高的流量大小。虽然在患者I的CS1中,速度大小有相当大的可变性,它们表现出更均匀和可预测的过渡。相比之下,病人II的CS2,幅度变化也很高的地方,由于内置假体的存在,显示不规则的流体行为。该横截面与流体分叉的边界重合。此外,血管内动脉瘤修复引起的不规则几何形状有助于血流中断,因为内置假体调整到内皮,重塑自身以符合血管壁。在这种情况下,速度值的显著变化,压差波动高达10%,和较低的壁剪切应力表明血管内假体对血流行为的显着影响。这些流动干扰,当心率加重时,可能会导致血管解剖结构和位移的变化,导致假体-内皮连续性的破坏,从而导致患者的临床并发症。
    This work analyzes hemodynamic phenomena within the aorta of two elderly patients and their impact on blood flow behavior, particularly affected by an endovascular prosthesis in one of them (Patient II). Computational Fluid Dynamics (CFD) was utilized for this study, involving measurements of velocity, pressure, and wall shear stress (WSS) at various time points during the third cardiac cycle, at specific positions within two cross sections of the thoracic aorta. The first cross-section (Cross-Section 1, CS1) is located before the initial fluid bifurcation, just before the right subclavian artery. The second cross-section (Cross-Section 2, CS2) is situated immediately after the left subclavian artery. The results reveal that, under regular aortic geometries, velocity and pressure magnitudes follow the principles of fluid dynamics, displaying variations. However, in Patient II, an endoprosthesis near the CS2 and the proximal border of the endoprosthesis significantly disrupts fluid behavior owing to the pulsatile flow. The cross-sectional areas of Patient I are smaller than those of Patient II, leading to higher flow magnitudes. Although in CS1 of Patient I, there is considerable variability in velocity magnitudes, they exhibit a more uniform and predictable transition. In contrast, CS2 of Patient II, where magnitude variation is also high, displays irregular fluid behavior due to the endoprosthesis presence. This cross-section coincides with the border of the fluid bifurcation. Additionally, the irregular geometry caused by endovascular aneurysm repair contributes to flow disruption as the endoprosthesis adjusts to the endothelium, reshaping itself to conform with the vessel wall. In this context, significant alterations in velocity values, pressure differentials fluctuating by up to 10%, and low wall shear stress indicate the pronounced influence of the endovascular prosthesis on blood flow behavior. These flow disturbances, when compounded by the heart rate, can potentially lead to changes in vascular anatomy and displacement, resulting in a disruption of the prosthesis-endothelium continuity and thereby causing clinical complications in the patient.
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  • 文章类型: Journal Article
    细胞过程通常由生物细胞中存在的所有蛋白质共同进行,即蛋白质组。基于质谱的方法已被证明在鉴定和定量蛋白质组的组成蛋白方面特别成功。包括蛋白质的不同分子形式。然而,单独的蛋白质序列不能揭示已鉴定蛋白质的功能或功能障碍。将功能或功能障碍分配给蛋白质的直接方法是表征其结构和动力学。然而,一种能够大规模表征蛋白质和蛋白质复合物详细结构的方法,在细胞过程的背景下,系统的方式还不存在。这里,我们讨论了串联离子迁移/质谱(串联IM/MS)方法提供这种能力的潜力。我们强调了这些方法的能力,使用两个案例研究的蛋白质系统泛素和抗生物素蛋白使用串联-TIMS/MS技术在我们实验室开发,并讨论这些结果在串联-IM/MS的更广泛领域的其他发展的背景下。
    Cellular processes are usually carried out collectively by the entirety of all proteins present in a biological cell, i.e. the proteome. Mass spectrometry-based methods have proven particularly successful in identifying and quantifying the constituent proteins of proteomes, including different molecular forms of a protein. Nevertheless, protein sequences alone do not reveal the function or dysfunction of the identified proteins. A straightforward way to assign function or dysfunction to proteins is characterization of their structures and dynamics. However, a method capable to characterize detailed structures of proteins and protein complexes in a large-scale, systematic manner within the context of cellular processes does not yet exist. Here, we discuss the potential of tandem-ion mobility / mass spectrometry (tandem-IM/MS) methods to provide such ability. We highlight the capability of these methods using two case studies on the protein systems ubiquitin and avidin using the tandem-TIMS/MS technology developed in our laboratory and discuss these results in the context of other developments in the broader field of tandem-IM/MS.
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  • 文章类型: Journal Article
    背景:植物解剖学的显微分析是生物学中研究结构和功能的常用程序,需要高质量的切片才能进行精确测量。样本的手工切片通常限于中等软组织,而较硬的样本禁止手工切片和/或导致厚度不一致。
    结果:在这里,我们提出了一种清晰描述的手工切片方法和一种新颖的切片机设计,它们共同提供了对各种植物样品类型进行切片的方法。所描述的用于草本茎的手动切片方法对于较软的受试者效果很好,但对于具有次生生长的样品不太适合(例如,木材生产)。相反,“Rapid-Tome”是一种新颖的工具,用于切割柔软和坚韧的高纵横比样品,如茎和根,具有优良的样品控制。Rapid-Tome可以在大约18小时内在大学制造商空间常见的中等质量打印机上进行3D打印。打印和修整后,Rapid-Tome组装在五金店常见的五个金属零件需要几分钟的时间。用户对各种植物样本进行了切片,包括柳枝须(Panicumvirgatum)的空心节间,含有通erenchyma的纤维柳枝草根部,和东部红雪松(Juniperusvirginiana)和美国无花果(Platanusoccidentalis)的木质分支。与Rapid-Tome产生的切片的比较分析很容易显示,春季无花果木质部血管面积的季节性生长存在显着差异(49%)与夏季(23%)。此外,没有经验的高中生在不到一个小时的时间内制作了带有Rapid-Tome的切片,足以对各种植物样品进行比较分析。
    结论:所描述的手切片方法适用于较软组织,包括空心茎草和类似样品。此外,Rapid-Tome提供了安全生产更坚韧的植物材料的高质量部分的能力,以传统的显微切片的一小部分成本与出色的样品控制相结合。Rapid-Tome的特点是快速切片,样本推进,刀片更换,和样品的变化;它是高度便携,可以很容易地使用与最少的培训,使生产的薄切片可供教室和外展使用,除了研究。
    BACKGROUND: Microscopic analysis of plant anatomy is a common procedure in biology to study structure and function that requires high-quality sections for accurate measurements. Hand sectioning of specimens is typically limited to moderately soft tissue while harder samples prohibit sectioning by hand and/or result in inconsistent thicknesses.
    RESULTS: Here we present both a clearly described hand-sectioning method and a novel microtome design that together provide the means to section a variety of plant sample types. The described hand-sectioning method for herbaceous stems works well for softer subjects but is less suitable for samples with secondary growth (e.g., wood production). Instead, the \"Rapid-Tome\" is a novel tool for sectioning both soft and tougher high-aspect-ratio samples, such as stems and roots, with excellent sample control. The Rapid-Tome can be 3D-printed in approximately 18 h on a mid-quality printer common at university maker spaces. After printing and trimming, Rapid-Tome assembly takes a few minutes with five metal parts common at hardware stores. Users sectioned a variety of plant samples including the hollow internodes of switchgrass (Panicum virgatum), fibrous switchgrass roots containing aerenchyma, and woody branches of eastern red cedar (Juniperus virginiana) and American sycamore (Platanus occidentalis). A comparative analyses with Rapid-Tome-produced sections readily revealed a significant difference in seasonal growth of sycamore xylem vessel area in spring (49%) vs. summer (23%). Additionally, high school students with no prior experience produced sections with the Rapid-Tome adequate for comparative analyses of various plant samples in less than an hour.
    CONCLUSIONS: The described hand-sectioning method is suitable for softer tissues, including hollow-stemmed grasses and similar samples. In addition, the Rapid-Tome provides capacity to safely produce high-quality sections of tougher plant materials at a fraction of the cost of traditional microtomes combined with excellent sample control. The Rapid-Tome features rapid sectioning, sample advancement, blade changes, and sample changes; it is highly portable and can be used easily with minimal training making production of thin sections accessible for classroom and outreach use, in addition to research.
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  • 文章类型: Journal Article
    Partial ionization cross sections are the absolute yields of specific ions from an electron-molecule collision. They are necessary for modeling plasmas and for determining the sensitivity of mass spectrometers, among other applications. One mass-spectrometric application is estimating the abundance of organic compounds on Mars, as sampled by the rover Curiosity. This is a report of semitheoretical data obtained for a collection of organic molecules identified as possible biomarkers in this exotic context.
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  • 文章类型: Evaluation Study
    本文的目的是使用meta骨的三维几何和惯性分析来确定个体的性别。使用AquilionOne320切片CT扫描仪扫描了60名成年中国男女受试者的meta骨。重建了跖骨的三维模型,此后,采用以质心为原点和三个惯性主轴的新型软件进行模型对齐。评估了八个几何和惯性变量:骨骼长度,骨宽度,骨高度,表面积与体积比,骨密度,和围绕x的主要惯性矩,y,z轴。此外,使用逐步判别函数分析建立判别函数。执行交叉验证程序以评估函数的判别准确性。结果表明,惯性变量表现出显著的性二态性,特别是围绕z轴的主要惯性矩。在表面积与体积比中发现了最高的双态值,绕z轴的主要惯性矩,和骨骼高度。性别确定的判别函数的准确率为88.3%至98.3%(交叉验证了88.3%-98.3%)。基于第三跖骨骨建立了最高的功能准确性。这项研究首次表明,人体骨骼的主要惯性矩可以成功地用于性别估计。总之,可以使用meta骨的几何和惯性变量的组合来准确地估计个体的性别。在将功能广泛应用于法医和生物考古学背景下的未识别骨骼之前,应在更大的样本量中进一步确认准确性,并针对不同的人群/年龄组进行测试或独立开发。
    The aim of the present paper is to determine the sex of the individual using three-dimensional geometric and inertial analyses of metatarsal bones. Metatarsals of 60 adult Chinese subjects of both sexes were scanned using Aquilion One 320 Slice CT Scanner. The three-dimensional models of the metatarsals were reconstructed, and thereafter, a novel software using the center of mass set as the origin and the three principal axes of inertia was employed for model alignment. Eight geometric and inertial variables were assessed: the bone length, bone width, bone height, surface-area-to-volume ratio, bone density, and principal moments of inertia around the x, y, and z axes. Furthermore, the discriminant functions were established using stepwise discriminant function analysis. A cross-validation procedure was performed to evaluate the discriminant accuracy of functions. The results indicated that inertial variables exhibit significant sexual dimorphism, especially principal moments of inertia around the z axis. The highest dimorphic values were found in the surface-area-to-volume ratio, principal moments of inertia around the z axis, and bone height. The accuracy rate of the discriminant functions for sex determination ranged from 88.3% to 98.3% (88.3%-98.3% cross-validated). The highest accuracy of function was established based on the third metatarsal bone. This study showed for the first time that the principal moment of inertia of the human bone may be successfully implemented for sex estimation. In conclusion, the sex of the individual can be accurately estimated using a combination of geometric and inertial variables of the metatarsal bones. The accuracy should be further confirmed in a larger sample size and be tested or independently developed for distinct population/age groups before the functions are widely applied in unidentified skeletons in forensic and bioarcheological contexts.
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  • 文章类型: Journal Article
    Instrument failure during root canal preparation is still a concern among endodontists. However, it remains unclear whether the use of more martensitic alloys or the cross-sectional design parameters (i.e., core mass) significantly improve fracture resistance. The aim of the study was to evaluate the impact of core mass and alloy on dynamic cyclic fatigue resistance of nickel-titanium endodontic instruments in matching artificial canals at body temperature. Two groups were tested. (A) taper 0.04: F360 (Komet, Lemgo, Germany), Twisted file (Sybron Endo, Glendora, CA, USA) (=TF), JIZAI (Mani, Tochigi, Japan) (=J_04) (all size #25) and the variable tapered TruNatomy (Dentsply, Ballaigues, Switzerland) (size #26) (=TN). (B) size #25; taper 0.06: (Mtwo (VDW, Munich, Germany), JIZAI (Mani) (=J_06), and variable tapered Hyflex EDM OneFile (Coltene Whaledent, Altstätten, Switzerland) (=HF). Time, number of cycles to fracture (NCF), and number and length of fractured fragments were recorded and statistically analysed using ANOVA Student-Newman-Keuls, Kruskal-Wallis or Chi-square test (significance level = 0.05). (A) TN showed the significantly shortest time until fracture, followed by TF, F360 and J_04 which also differed significantly, while NCF showed the following order: F360 < TN < TF < J_04 (p < 0.05). Only one J_04 but all instruments of the other groups fractured within the test-limit of 10 min. (B) Mtwo was significantly inferior concerning time until fracture and NCF, compared to J_06 and HF (p < 0.05), which did not differ significantly (p > 0.05). While all Mtwo instruments fractured, only four instruments failed in the other groups (p < 0.05). Within the limitations of this study, alloy and cross-sectional design (i.e., core mass) were critical factors regarding instrument failure, but none of these factors could be determined as a main parameter for increased or decreased time, and cycles to fracture. Rather, it seemed to be the interaction of multiple factors (e.g., longitudinal and cross-sectional design, alloy, and rotational speed) that was responsible for differences in the time and cycles to fracture. Nonetheless, all instruments had lifetimes that allow safe clinical use. However, the superiority or inferiority of an instrument with regard to cyclic fatigue based on laboratory results-even when identical trajectories are guaranteed-may be considered questionable, as the characteristics and design parameters of the instruments vary considerably, and the experimental setups lack additional clinical parameters and thus clinical relevance.
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  • 文章类型: Journal Article
    The cross sections for nuclear reactions natEr(α,x) were measured in the energy range 60 → 10 MeV using the stacked-foil technique. The experiments were carried out in a wider energy range in comparison with previous works. The results are consistent with other studies and modeling using TENDL-2019. The 167Tm yield was 5.4 MBq/μAh in the range 60 → 30 MeV, and the main long-lived impurity is 168Tm (0.78% in terms of activity). The 165Tm yield is 4.6 MBq/μAh (60 → 40 MeV). 169Yb is formed with a yield of 1.0 MBq/μAh in the energy range 60 → 20 MeV.
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  • 文章类型: Journal Article
    The aim of this letter is to suggest new semi-empirical formulae for the prediction of (n,d) cross sections with a neutron energy of 14-15 MeV. In this context, the cross sections are calculated using systematic that is function only of the reaction Q-value and mass number A. The (n,d) reactions are analyzed by using the systematics based on the statistical theory. Thus, the present semi-empirical formulae compared with the cross section data in literature give a good fit for the prediction of the (n,d) cross sections at 14-15 MeV.
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  • 文章类型: Journal Article
    该对铜放射性核素64Cu/67Cu(T1/2=12。7h/61.8h)允许,分别,PET成像和靶向β治疗。对带有带电粒子的67Cu的不同生产路线进行了分析,并对反应70Zn(d,x)路线被确定为有希望的路线。它可以允许在没有64Cu的情况下生产67Cu。生产横截面已测量到28.7MeV。使用众所周知的堆叠箔技术,使用97.5%富集的70Zn自制电镀靶进行测量。这些测量在较高的入射能量下补充了核数据库中唯一可用的数据集。结果表明,使用26MeV的氘束和高度富集的70Zn靶,可以产生与使用光生产获得的相当的高纯度67Cu。这种生产路线对于正在开发的未来线性加速器可能是感兴趣的,如果开发了足够的目标,则可以使用mA氘束。
    The pair of copper radionuclides 64Cu/67Cu (T1/2 = 12. 7 h/61.8 h) allows, respectively, PET imaging and targeted beta therapy. An analysis of the different production routes of 67Cu with charged particles was performed and the reaction 70Zn(d,x) route was identified as a promising one. It may allow the production of 67Cu without 64Cu. The production cross section has been measured up to 28.7 MeV. Measurements were done using the well-known stacked-foils technique using 97.5% enriched 70Zn homemade electroplated targets. These measurements complement at higher incident energies the only set of data available in nuclear databases. The results show that using a 26 MeV deuteron beam and a highly enriched 70Zn target, it is possible to produce high purity 67Cu comparable to that obtained using photoproduction. This production route can be of interest for future linear accelerators under development where mA deuteron beams can be available if adequate targetry is developed.
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  • 文章类型: Journal Article
    在RIKENAVF回旋加速器上测量了α粒子诱导的natNd反应的激发函数,直至50MeV。要导出横截面激活方法,采用堆叠靶技术和γ射线能谱。153,145Sm的地层,151,150,149,148m,148g,144,143Pm,并对149,147Nd进行了调查。将结果与以前的实验数据和TENDL-2019数据进行了比较。发现其中大多数差异。
    Excitation functions of alpha-particle induced reactions on natNd up to 50 MeV were measured at the RIKEN AVF cyclotron. To derive cross sections activation method, stacked target technique and gamma-ray spectrometry were adopted. Formations of 153,145Sm, 151,150,149,148m,148g,144,143Pm, and 149,147Nd were investigated. The results were compared with the previous experimental data and the TENDL-2019 data. Discrepancies among most of them were found.
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