Enzymatic Sialylation of N-Linked Oligosaccharides Using an α-(2,3)-Specific trans-Sialidase from Trypanosoma cruzi: Structural Identification Using a Three-Dimensional Elution Mapping Technique

1995 ◽  
Vol 230 (2) ◽  
pp. 333-342 ◽  
Author(s):  
N. Takahashi ◽  
K.B. Lee ◽  
H. Nakagawa ◽  
Y. Tsukamoto ◽  
Y. Kawamura ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Three Dimensional ◽  
Structural Identification ◽  
Mapping Technique ◽  
Enzymatic Sialylation

Epitaxial Ni nanoparticles on CaF2(001), (110) and (111) surfaces studied by three-dimensional RHEED, GIXD and GISAXS reciprocal-space mapping techniques

2017 ◽  
Vol 50 (3) ◽  
pp. 830-839 ◽  
Author(s):  
S. M. Suturin ◽  
V. V. Fedorov ◽  
A. M. Korovin ◽  
N. S. Sokolov ◽  
A. V. Nashchekin ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
High Energy ◽  
Reciprocal Space ◽  
Mapping Technique ◽  
Face Centered Cubic ◽  
X Ray ◽  
Cubic Lattice ◽  
Face Centered

The development of growth techniques aimed at the fabrication of nanoscale heterostructures with layers of ferroic 3dmetals on semiconductor substrates is very important for their potential usage in magnetic media recording applications. A structural study is presented of single-crystal nickel island ensembles grown epitaxially on top of CaF2/Si insulator-on-semiconductor heteroepitaxial substrates with (111), (110) and (001) fluorite surface orientations. The CaF2buffer layer in the studied multilayer system prevents the formation of nickel silicide, guides the nucleation of nickel islands and serves as an insulating layer in a potential tunneling spin injection device. The present study, employing both direct-space and reciprocal-space techniques, is a continuation of earlier research on ferromagnetic 3dtransition metals grown epitaxially on non-magnetic and magnetically ordered fluorides. It is demonstrated that arrays of stand-alone faceted nickel islands with a face-centered cubic lattice can be grown controllably on CaF2surfaces of (111), (110) and (001) orientations. The proposed two-stage nickel growth technique employs deposition of a thin seeding layer at low temperature followed by formation of the islands at high temperature. The application of an advanced three-dimensional mapping technique exploiting reflection high-energy electron diffraction (RHEED) has proved that the nickel islands tend to inherit the lattice orientation of the underlying fluorite layer, though they exhibit a certain amount of {111} twinning. As shown by scanning electron microscopy, grazing-incidence X-ray diffraction (GIXD) and grazing-incidence small-angle X-ray scattering (GISAXS), the islands are of similar shape, being faceted with {111} and {100} planes. The results obtained are compared with those from earlier studies of Co/CaF2epitaxial nanoparticles, with special attention paid to the peculiarities related to the differences in lattice structure of the deposited metals: the dual-phase hexagonal close-packed/face-centered cubic lattice structure of cobalt as opposed to the single-phase face-centered cubic lattice structure of nickel.

Evaluation of left ventricular volumes and ejection fraction with a nonfluoroscopic endoventricular three-dimensional mapping technique

2000 ◽  
Vol 140 (4) ◽  
pp. 596-602 ◽  
Author(s):  
Glenn Van Langenhove ◽  
Jaap N. Hamburger ◽  
Peter C. Smits ◽  
Mariano Albertal ◽  
Emile Onderwater ◽  
...  
Keyword(s):  
Ejection Fraction ◽  
Three Dimensional ◽  
Left Ventricular ◽  
Mapping Technique ◽  
Left Ventricular Volumes ◽  
Ventricular Volumes ◽  
Three Dimensional Mapping ◽  
Dimensional Mapping

Virtual electrode theory explains pacing threshold increase caused by cardiac tissue damage

2004 ◽  
Vol 286 (6) ◽  
pp. H2183-H2194 ◽  
Author(s):  
Aleksandre T. Sambelashvili ◽  
Vladimir P. Nikolski ◽  
Igor R. Efimov
Keyword(s):  
Tissue Damage ◽  
Cardiac Tissue ◽  
Three Dimensional ◽  
Rabbit Heart ◽  
Mapping Technique ◽  
Electrode Polarization ◽  
Pacing Threshold ◽  
Antibody Staining ◽  
Threshold Increase ◽  
Virtual Electrode

The virtual electrode polarization (VEP) effect is believed to play a key role in electrical stimulation of heart muscle. However, under certain conditions, including clinically, its existence and importance remain unknown. We investigated the influence of acute tissue damage produced by continuous pacing with strong current (40-mA, 4-ms biphasic pulses with 4-Hz frequency for 5 min) on stimulus-generated VEPs and pacing thresholds. A fluorescent optical mapping technique was used to obtain stimulus-induced transmembrane potential distribution around a pacing electrode applied to the ventricular surface of a Langendorff-perfused rabbit heart ( n = 5). Maps and pacing thresholds were recorded before and after tissue damage. Spatial extents of electroporation and cell uncoupling were assessed by propidium iodide ( n = 2) and connexin43 ( n = 3) antibody staining, respectively. On the basis of these data, passive and active three-dimensional bidomain models were built to determine VEP patterns and thresholds for different-sized areas of the damaged region. Electrophysiological results showed that acute tissue damage led to disappearance of the VEP with an associated significant increase in pacing thresholds. Damage was expressed in electroporation and cell uncoupling within a ∼1.0-mm-diameter area around the tip of the electrode. According to computer simulations, cell uncoupling, rather than electroporation, might be the direct cause of VEP elimination and threshold increase, which was nonlinearly dependent on the size of the damaged region. Fiber rotation with depth did not substantially affect the numerical results. The study explains failure to stimulate damaged tissue within the concepts of the VEP theory.

Three-dimensional endocardial impedance mapping: a new approach for myocardial infarction assessment

2001 ◽  
Vol 280 (1) ◽  
pp. H179-H188 ◽  
Author(s):  
Tamir Wolf ◽  
Lior Gepstein ◽  
Gal Hayam ◽  
Asaph Zaretzky ◽  
Rona Shofty ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Three Dimensional ◽  
Interventional Cardiology ◽  
Mapping Technique ◽  
Control Group ◽  
Myocardial Tissue ◽  
Coronary Artery Ligation ◽  
Accurate Identification ◽  
Artery Ligation ◽  
Electromechanical Mapping

Precise identification of infarcted myocardial tissue is of importance in diagnostic and interventional cardiology. A three-dimensional, catheter-based endocardial electromechanical mapping technique was used to assess the ability of local endocardial impedance in delineating the exact location, size, and border of canine myocardial infarction. Electromechanical mapping of the left ventricle was performed in a control group ( n = 10) and 4 wk after left anterior descending coronary artery ligation ( n = 10). Impedance, bipolar electrogram amplitude, and endocardial local shortening (LS) were quantified. The infarcted area was compared with the corresponding regions in controls, revealing a significant reduction in impedance values [infarcted vs. controls: 168.8 ± 11.7 and 240.7 ± 22.3 Ω, respectively (means ± SE), P < 0.05] bipolar electrogram amplitude (1.8 ± 0.2 mV, 4.4 ± 0.7 mV, P < 0.05), and LS (−2.36 ± 1.6%, 11.9 ± 0.9%, P < 0.05). The accuracy of the impedance maps in delineating the location and extent of the infarcted region was demonstrated by the high correlation with the infarct area (Pearson's correlation coefficient = 0.942) and the accurate identification of the infarct borders in pathology. By accurately defining myocardial infarction and its borders, endocardial impedance mapping may become a clinically useful tool in differentiating healthy from necrotic myocardial tissue.

An advanced three-dimensional RHEED mapping approach to the diffraction study of Co/MnF2/CaF2/Si(001) epitaxial heterostructures

2016 ◽  
Vol 49 (5) ◽  
pp. 1532-1543 ◽  
Author(s):  
S. M. Suturin ◽  
A. M. Korovin ◽  
V. V. Fedorov ◽  
G. A. Valkovsky ◽  
M. Tabuchi ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Cross Sections ◽  
Three Dimensional ◽  
Sample Surface ◽  
High Energy ◽  
Mapping Technique ◽  
Plan View ◽  
Mapping Approach ◽  
Three Dimensional Mapping ◽  
Dimensional Mapping

An advanced three-dimensional mapping approach utilizing reflection high-energy electron diffraction (RHEED) is introduced. The application of the method is demonstrated in detail by resolving the crystal structure and epitaxial relations of individual components within epitaxially grown magnetically ordered Co/MnF2/CaF2/Si(001) heterostructures. The electron diffraction results are cross-checked using synchrotron X-ray diffraction measurements. A number of advantages of the three-dimensional mapping technique as compared to conventional electron diffraction are demonstrated. Not least amongst these is the possibility to build arbitrary planar cross sections and projections through reciprocal space, including the plan-view projection onto the plane parallel to the sample surface, which is otherwise impossible to obtain.

scholarly journals Transmigration of Trypanosoma cruzi trypomastigotes through 3D cultures resembling a physiological environment

2019 ◽  
Author(s):  
Matías Exequiel Rodríguez ◽  
Mariana Rizzi ◽  
Lucas D. Caeiro ◽  
Yamil E. Masip ◽  
Alina Perrone ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Three Dimensional ◽  
3D Cultures ◽  
Monolayer Cultures ◽  
Host Parasite Interactions ◽  
Virulent Strains ◽  
Host Parasite ◽  
3D Spheroids

AbstractChaga’ disease, caused by the kinetoplastid parasite Trypanosoma cruzi, presents a variety of chronic clinical manifestations whose determinants are still unknown but probably influenced by the host-parasite interplay established during the first stages of the infection, when bloodstream circulating trypomastigotes disseminate to different organs and tissues. After leaving the blood, trypomastigotes must migrate through tissues to invade cells and establish a chronic infection. How this process occurs remains unexplored. Three-dimensional (3D) cultures are physiologically relevant because mimic the microarchitecture of tissues and provide an environment similar to the encountered in natural infections. In this work, we combined the 3D culture technology with host-pathogen interaction, by studying transmigration of trypomastigotes into 3D spheroids. T. cruzi strains with similar infection dynamics in 2D monolayer cultures but with different in vivo behavior (CL Brener, virulent; SylvioX10 no virulent) presented different infection rates in spheroids (CL Brener ∼40%, SylvioX10 <10%). Confocal microscopy images evidenced that trypomastigotes from CL Brener and other highly virulent strains presented a great ability to transmigrate inside 3D spheroids: as soon as 4 hours post infection parasites were found at 50 µm in depth inside the spheroids. CL Brener trypomastigotes were evenly distributed and systematically observed in the space between cells, suggesting a paracellular route of transmigration to deepen into the spheroids. On the other hand, poor virulent strains presented a weak migratory capacity and remained in the external layers of spheroids (<10µm) with a patch-like distribution pattern. The invasiveness -understood as the ability to transmigrate deep into spheroids- was not a transferable feature between strains, neither by soluble or secreted factors nor by co-cultivation of trypomastigotes from invasive and non-invasive strains. We also studied the transmigration of recent T. cruzi isolates from children that were born congenitally infected, which showed a high migrant phenotype while an isolate form an infected mother (that never transmitted the infection to any of her 3 children) was significantly less migratory. Altogether, our results demonstrate that in a 3D microenvironment each strain presents a characteristic migration pattern and distribution of parasites in the spheroids that can be associated to their in vivo behavior. Certainly, the findings presented here could not have been studied with traditional 2D monolayer cultures.Author SummaryTrypanosoma cruzi is the protozoan parasite that causes Chaga’ disease, also known as American trypanosomiasis. Experimental models of the infection evidence that different strains of the parasite present different virulence in the host, which cannot be always reproduced in 2D monolayer cultures. Three dimensional (3D) cultures can be useful models to study complex host-parasite interactions because they mimic in vitro the microarchitecture of tissues and provide an environment similar to the encountered in natural infections. In particular, spheroids are small 3D aggregates of cells that interact with each other and with the extracellular matrix that they secrete resembling the original microenvironment both functionally and structurally. Spheroids have rarely been employed to explore infectious diseases and host-parasite interactions. In this work we studied how bloodstream trypomastigotes transmigrate through 3D spheroids mimicking the picture encountered by parasites in tissues soon after leaving circulation. We showed that the behavior of T. cruzi trypomastigotes in 3D cultures reflects their in vivo virulence: virulent strains transmigrate deeply into spheroids while non-virulent strains remain in the external layers of spheroids. Besides, this work demonstrates the usefulness of 3D cultures as an accurate in vitro model for the study of host-pathogen interactions that could not be addressed with conventional monolayer cultures.

scholarly journals Pipeline architectures of Three-dimensional daubechies wavelet transform using hybrid method

2019 ◽  
Vol 15 (1) ◽  
pp. 240
Author(s):  
Noor Huda Ja’afar ◽  
Afandi Ahmad
Keyword(s):  
Wavelet Transform ◽  
Image Compression ◽  
Hybrid Method ◽  
Medical Image ◽  
Three Dimensional ◽  
Building Blocks ◽  
Mapping Technique ◽  
Discrete Wavelet ◽  
Daubechies Wavelet ◽  
Medical Image Compression

<span>The application of three-dimensional (3-D) medical image compression systems uses several building blocks for its computationally intensive algorithms to perform matrix transformation operations. Complexity in addressing large medical volumes data has resulted in vast challenges from a hardware implementation perspective. This paper presents an approach towards very-large-scale-integration (VLSI) implementation of 3-D Daubechies wavelet transform for medical image compression. Discrete wavelet transform (DWT) algorithm is used to design the proposed architectures with pipelined direct mapping technique. Hybrid method use a combination of hardware description language (HDL) and G-code, where this method provides an advantage compared to traditional method. The proposed pipelined architectures are deployed for adaptive transformation process of medical image compression applications. The soft IP core design was targeted on to Xilinx field programmable gate array (FPGA) single board RIO (sbRIO 9632). Results obtained for 3-D DWT architecture using Daubechies 4-tap (Daub4) implementation exhibits promising results in terms of area, power consumption and maximum frequency compared to Daubechies 6-tap (Daub6).</span>

scholarly journals A three-dimensional surface elastic model for vibration analysis of functionally graded arbitrary straight-sided quadrilateral nanoplates under thermal environment

2020 ◽  
Vol 37 ◽  
pp. 72-99
Author(s):  
A Shahabodini ◽  
R Ansari ◽  
H Rouhi
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Thermal Environment ◽  
Three Dimensional ◽  
Functionally Graded ◽  
Mapping Technique ◽  
Elastic Model ◽  
Size Dependent ◽  
Present Solution ◽  
Effect Of Surface

Abstract In this paper, a three-dimensional (3D) size-dependent formulation is developed for the free vibrations of functionally graded quadrilateral nanoplates subjected to thermal environment. The plate model is constructed within the frameworks of the Gurtin–Murdoch surface and the 3D elasticity theories. In this way, the effect of surface free energy and all the components of stress and strain tensors are considered without any initial assumption on them as there is no need to assume the variation of transverse normal stress inside the bulk material in advance. The variational differential quadrature approach and the mapping technique are applied to derive a discretized weak form of the governing equations. The present solution method bypasses the transformation and discretization of the higher order derivatives appearing in the equations of the strong form. The effects of surface stress, thermal environment, material gradient index and geometrical properties on the size-dependent vibrational behavior of quadrilateral nanoplates are investigated. It is observed that the thermal load intensifies the effect of surface free energy on the natural frequency of the nanoplates. The present model is exact in the extent of the continuum models and can be employed for structures with any thickness–span ratios.

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