Continuous-resolution-level constraints in variational design of multiresolution shapes

1998 ◽  
Vol 14 (4) ◽  
pp. 177-192 ◽  
Author(s):  
Shigeo Takahashi ◽  
Yoshihisa Shinagawa ◽  
Tosiyasu L. Kunii
Keyword(s):  
Variational Design ◽  
Resolution Level

Experimental Determination of the Effective Resolution Limit in Thick Specimens at High Voltages

1975 ◽  
Vol 33 ◽  
pp. 664-665
Author(s):  
Mircea Fotino
Keyword(s):  
Experimental Approach ◽  
Chromatic Aberration ◽  
Resolving Power ◽  
Biological Research ◽  
Specimen Thickness ◽  
Resolution Limit ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Resolution Level

The use of thick specimens (0.5 μm to 5.0 μm or more) is one of the most resourceful applications of high-voltage electron microscopy in biological research. However, the energy loss experienced by the electron beam in the specimen results in chromatic aberration and thus in a deterioration of the effective resolving power. This sets a limit to the maximum usable specimen thickness when investigating structures requiring a certain resolution level.An experimental approach is here described in which the deterioration of the resolving power as a function of specimen thickness is determined. In a manner similar to the Rayleigh criterion in which two image points are considered resolved at the resolution limit when their profiles overlap such that the minimum of one coincides with the maximum of the other, the resolution attainable in thick sections can be measured by the distance from minimum to maximum (or, equivalently, from 10% to 90% maximum) of the broadened profile of a well-defined step-like object placed on the specimen.

Ultrathin Platinum Crystal Surface Structures

1985 ◽  
Vol 43 ◽  
pp. 394-395
Author(s):  
R. L. Hines
Keyword(s):  
Crystal Surface ◽  
Surface Structures ◽  
Platinum Surface ◽  
Platinum Surfaces ◽  
Resolution Level ◽  
Experimental Facilities ◽  
Carbon Backing ◽  
Mesh Grid ◽  
Atom Layer

The importance of atom layer terraces or steps on platinum surfaces used for catalysis as discussed by Somorjai justifies an extensive investigation of the structure of platinum surfaces through electron microscopy at the atomic resolution level. Experimental and theoretical difficulties complicate the quantitative determination of platinum surface structures but qualitative observation of surface structures on platinum crystals is now possible with good experimental facilities.Ultrathin platinum crystals with nominal 111 orientation are prepared using the procedure reported by Hines without the application of a carbon backing layer. Platinum films with thicknesses of about ten atom layers are strong enough so that they can be mounted on grids to provide ultrathin platinum crystals for examination of surface structure. Crystals as thin as possible are desired to minimize the theoretical difficulties in analyzing image contrast to determine structure. With the current preparation procedures the crystals frequently cover complete openings on a 400 mesh grid.

scholarly journals DNA Methylation Profiles of Tph1A and BDNF in Gut and Brain of L. Rhamnosus-Treated Zebrafish

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 142
Author(s):  
Mariella Cuomo ◽  
Luca Borrelli ◽  
Rosa Della Monica ◽  
Lorena Coretti ◽  
Giulia De Riso ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
The Past ◽  
Targeted Analysis ◽  
Lack Of Information ◽  
High Resolution Power ◽  
Resolution Level ◽  
Health And Disease ◽  
High Doses ◽  
The Brain

The bidirectional microbiota–gut–brain axis has raised increasing interest over the past years in the context of health and disease, but there is a lack of information on molecular mechanisms underlying this connection. We hypothesized that change in microbiota composition may affect brain epigenetics leading to long-lasting effects on specific brain gene regulation. To test this hypothesis, we used Zebrafish (Danio Rerio) as a model system. As previously shown, treatment with high doses of probiotics can modulate behavior in Zebrafish, causing significant changes in the expression of some brain-relevant genes, such as BDNF and Tph1A. Using an ultra-deep targeted analysis, we investigated the methylation state of the BDNF and Tph1A promoter region in the brain and gut of probiotic-treated and untreated Zebrafishes. Thanks to the high resolution power of our analysis, we evaluated cell-to-cell methylation differences. At this resolution level, we found slight DNA methylation changes in probiotic-treated samples, likely related to a subgroup of brain and gut cells, and that specific DNA methylation signatures significantly correlated with specific behavioral scores.

scholarly journals Challenges to the validity of topic reconstruction

2021 ◽  
Author(s):  
Matthias Held ◽  
Grit Laudel ◽  
Jochen Gläser
Keyword(s):  
Data Model ◽  
Ground Truth ◽  
Data Models ◽  
Bibliographic Coupling ◽  
Parameter Setting ◽  
Meso Level ◽  
Resolution Level ◽  
Micro Level ◽  
Research Questions ◽  
Model Algorithm

AbstractIn this paper we utilize an opportunity to construct ground truths for topics in the field of atomic, molecular and optical physics. Our research questions in this paper focus on (i) how to construct a ground truth for topics and (ii) the suitability of common algorithms applied to bibliometric networks to reconstruct these topics. We use the ground truths to test two data models (direct citation and bibliographic coupling) with two algorithms (the Leiden algorithm and the Infomap algorithm). Our results are discomforting: none of the four combinations leads to a consistent reconstruction of the ground truths. No combination of data model and algorithm simultaneously reconstructs all micro-level topics at any resolution level. Meso-level topics are not reconstructed at all. This suggests (a) that we are currently unable to predict which combination of data model, algorithm and parameter setting will adequately reconstruct which (types of) topics, and (b) that a combination of several data models, algorithms and parameter settings appears to be necessary to reconstruct all or most topics in a set of papers.

STEM Analysis of Atom Location in (Cu, Au, Ni)6Sn5 Intermetallic Compounds

2018 ◽  
Vol 273 ◽  
pp. 95-100
Author(s):  
Wen Hui Yang ◽  
Tomokazu Yamamoto ◽  
Kazuhiro Nogita ◽  
Syo Matsumura
Keyword(s):  
Dark Field ◽  
Hexagonal Structure ◽  
Atomic Resolution ◽  
Chemical Mapping ◽  
Soldering Process ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Direct Alloying ◽  
Resolution Level ◽  
Evolution Of Microstructure

Cu6Sn5 is an important intermetallic compound in soldering and electronic packaging. It is formed at the interface between molten solder and substrate during the soldering process, and the evolution of microstructure and properties also occurs in service. Previous studies revealed that Au and Ni are stabilization alloying elements for hexagonal η-Cu6Sn5 intermetallic. For better understanding of stabilization mechanisms at atomic resolution level, in this work, we made an attempt atomic structure analysis on a stoichiometric (Cu, Au, Ni)6Sn5 intermetallic prepared by direct alloying. High-angle annular dark-field (HAADF) imaging and atomic-resolution chemical mapping were taken by the aberration-corrected (Cs-corrected) scanning transmission electron microscopy (STEM). It is found that Au and Ni doped Cu6Sn5 has hexagonal structure. The atom sites of Cu1 and Sn can be distinguished in atomic-resolution images after being observed from orientation [2110], which is also confirmed by atomic-resolution chemical mapping analysis. Importantly, atomic-resolution about distribution of alloying Au atom was directly observed, and Au atoms occupy the Cu1 sites in η-Cu6Sn5.

scholarly journals Variational design method for dipole-based volumetric artificial media

2019 ◽  
Vol 27 (5) ◽  
pp. 6512 ◽  
Author(s):  
Roberto Zecca ◽  
Daniel L. Marks ◽  
David R. Smith
Keyword(s):  
Design Method ◽  
Variational Design

scholarly journals MULTIRESOLUTION CONTROL OF CURVES AND SURFACES WITH A SELF-SIMILAR MODEL

Fractals ◽  
2010 ◽  
Vol 18 (03) ◽  
pp. 271-286 ◽  
Author(s):  
HOUSSAM HNAIDI ◽  
ERIC GUÉRIN ◽  
SAMIR AKKOUCHE
Keyword(s):  
Wavelet Transform ◽  
Control Point ◽  
Iterated Function Systems ◽  
Control Points ◽  
Similar Model ◽  
Surface Theory ◽  
Curves And Surfaces ◽  
Iterated Function ◽  
Resolution Level ◽  
Self Similar

This paper presents two self-similar models that allow the control of curves and surfaces. The first model is based on IFS (Iterated Function Systems) theory and the second on subdivision curve and surface theory. Both of these methods employ the detail concept as in the wavelet transform, and allow the multiresolution control of objects with control points at any resolution level.In the first model, the detail is inserted independently of control points, requiring it to be rotated when applying deformations. In contrast, the second method describes details relative to control points, allowing free control point deformations.Modeling examples of curves and surfaces are presented, showing manipulation facilities of the models.

TOPOGRAPHIC MODELING OF #1 G-BANDED CHROMOSOME

1995 ◽  
Vol 03 (01) ◽  
pp. 27-39
Author(s):  
G. RUBBIA RINALDI ◽  
N. BIANCHI ◽  
G. MARVEGGIO ◽  
A. MORABITO ◽  
P. MUSSIO ◽  
...  
Keyword(s):  
Information Diffusion ◽  
Quantitative Description ◽  
Local Property ◽  
Optical Microscope ◽  
Input Image ◽  
Chromosome 1 ◽  
Lindenmayer Systems ◽  
Grey Tone ◽  
Resolution Level ◽  
Human Chromosome 1

An approach to a quantitative description of bands and interbands, representing alternating visible zones of chromatin packaging is presented. The study is performed on selected human chromosome (#1) obtained from G-banded metaphases observed by the optical microscope. In order to segment the image into structures of interest a topographic approach is proposed: greytone images are seen as landsurfaces (i.e., the grey tone of a pixel is the elevation in that point) and structures to be detected are considered as topographic relieves. In the segmentation process a rewriting process translates the greytone digital image into an image where each pixel is labelled by a symbol denoting the type of structure to which the pixel belongs. Rewriting is performed by repeatedly applying the rules of Bidimensional Lindenmayer Systems (BLS) to the input image. In each step BLS rules are applied to evaluate a local property. The repeated application of the rules combine the local properties of pixels up to an arbitrary distance, simulating an information diffusion process that determines the emergence of global properties of sets of pixels of arbitrary shape. Detected Troughs and Lowlands are interpreted as tracks of bands and interbands and from their description there derives a set of geometrical attributes. These attributes are useful to measure the distances between bands and interbands and hence to follow the dynamic packaging of chromosomes before cell division. Finally, topographic labelling seems to enhance the resolution level of chromosome features, especially for faint bands, thus it is reasonable to expect that even microvariations important in cytogenetic pathology can be detected.

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