A Relatively Inexpensive Microprocessor-Linked Digital Plamimeter for Electron Microscopic Morphometry

1981 ◽  
Vol 39 ◽  
pp. 266-269
Author(s):  
Lee D. Peachey
Keyword(s):  
Theoretical Basis ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Structural Data ◽  
Large Set ◽  
Dimensional Electron ◽  
Electron Microscopic ◽  
Morphometric Methods ◽  
Electron Microscopic Morphometry ◽  
Separate Step

Stereology provides a theoretical basis for powerful morphometric methods for the estimation of three-dimensional structural parameters from two-dimensional electron micrographs of cells and tissues. These methods assume at the start that one has a sufficiently large set of micrographs containing valid structural data. The task of obtaining from these micrographs the large quantity of data needed to get statistically valid results has been eased in two general ways. Sampling of data in the micrograph can be done rapidly by point and intersection counting methods. An alternate method, planimetry, obtains all the data in the micrograph, but in general is more time-consuming than point and intersection counting. Some of the relative inefficiency of planimetry is compensated when a digital planimeter is coupled with a computer. Areas and lengths can be computed simultaneously as fast as profiles are traced. Furthermore, rapid and numerically accurate compilation and statistical analysis of the data can be done automatically as the planimetry is done, not as a separate step after the data have been obtained.

Symmetry-adapted digital modeling III. Coarse-grained icosahedral viruses

2016 ◽  
Vol 72 (3) ◽  
pp. 324-337 ◽  
Author(s):  
A. Janner
Keyword(s):  
Lattice Point ◽  
Three Dimensional ◽  
Structural Data ◽  
Data Bank ◽  
Coarse Grained ◽  
Large Set ◽  
Fine Grained ◽  
Coarse Grained Model ◽  
Digital Modeling ◽  
Icosahedral Viruses

Considered is the coarse-grained modeling of icosahedral viruses in terms of a three-dimensional lattice (the digital modeling lattice) selected among the projected points in space of a six-dimensional icosahedral lattice. Backbone atomic positions (Cα's for the residues of the capsid and phosphorus atoms P for the genome nucleotides) are then indexed by their nearest lattice point. This leads to a fine-grained lattice point characterization of the full viral chains in the backbone approximation (denoted as digital modeling). Coarse-grained models then follow by a proper selection of the indexed backbone positions, where for each chain one can choose the desired coarseness. This approach is applied to three viruses, the Satellite tobacco mosaic virus, the bacteriophage MS2 and the Pariacoto virus, on the basis of structural data from the Brookhaven Protein Data Bank. In each case the various stages of the procedure are illustrated for a given coarse-grained model and the corresponding indexed positions are listed. Alternative coarse-grained models have been derived and compared. Comments on related results and approaches, found among the very large set of publications in this field, conclude this article.

Quantitative Three-Dimensional Reconstructions of Excitatory Synaptic Boutons in the “Barrel Field” of the Adult “Reeler” Mouse Somatosensory Neocortex: A Comparative Fine-Scale Electron Microscopic Analysis with the Wild Type Mouse

2019 ◽  
Vol 30 (5) ◽  
pp. 3209-3227
Author(s):  
Miriam Prume ◽  
Astrid Rollenhagen ◽  
Rachida Yakoubi ◽  
Kurt Sätzler ◽  
Joachim Hr Lübke
Keyword(s):  
Structural Parameters ◽  
Three Dimensional ◽  
Wild Type Mouse ◽  
Fine Scale ◽  
Synaptic Organization ◽  
Wild Type ◽  
Structural Determinants ◽  
Electron Microscopic ◽  
Synaptic Boutons ◽  
Active Zones

Abstract Synapses are key structural determinants for information processing and computations in the normal and pathologically altered brain. Here, the quantitative morphology of excitatory synaptic boutons in the “reeler” mutant, a model system for various neurological disorders, was investigated and compared with wild-type (WT) mice using high-resolution, fine-scale electron microscopy (EM) and quantitative three-dimensional (3D) models of synaptic boutons. Beside their overall geometry, the shape and size of presynaptic active zones (PreAZs) and postsynaptic densities (PSDs) forming the active zones and the three pools of synaptic vesicles (SVs), namely the readily releasable pool (RRP), the recycling pool (RP), and the resting pool, were quantified. Although the reeler mouse neocortex is severely disturbed, no significant differences were found in most of the structural parameters investigated: the size of boutons (~3 μm2), size of the PreAZs and PSDs (~0.17 μm2), total number of SVs, and SVs within a perimeter (p) of 10 nm and p20 nm RRP; the p60 nm, p100 nm, and p60–p200 nm RP; and the resting pool, except the synaptic cleft width. Taken together, the synaptic organization and structural composition of synaptic boutons in the reeler neocortex remain comparably “normal” and may thus contribute to a “correct” wiring of neurons within the reeler cortical network.

scholarly journals Study on the Technology of Solid Expandable Tubular in Open-Hole Well

2020 ◽  
Author(s):  
Xiaohua Zhu ◽  
Feilong Cheng ◽  
Changshuai Shi ◽  
Kailin Chen
Keyword(s):  
Theoretical Basis ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Great Influence ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Open Hole ◽  
Plastic Forming ◽  
Borehole Size ◽  
Shaft Wall

Abstract During the production and drilling of open hole wells, due to the uncertainty and complexity of the rock,The naked hole section is prone to accidents such as collapse of the shaft wall and leakage. In order to solve the above problems, this paper proposes the plugging technology of solid expandable tubualr(SET) in open-hole wells. Based on experimental data,this paper established a dynamic three-dimensional model which considers friction and contact. The author puts forward the applicability criterion of open hole and studies the sensitivity parameters of expansion cone. The research results show that when SET specifications are determined, the borehole size of the open hole well has a great influence on the contact pressure, residual stress, driving force and other factors after the SET is formed, and to a certain extent affects the subsequent service. In addition, the structural parameters of the expansion cone also have a great influence on the plastic forming of SET. The results of this paper provide guidelines and theoretical basis for the use of SET technology in open hole wells.

scholarly journals Chromosome Fragments Possessing Only One Kinetochore Can Congress to the Spindle Equator

1997 ◽  
Vol 136 (2) ◽  
pp. 229-240 ◽  
Author(s):  
Alexey Khodjakov ◽  
Richard W. Cole ◽  
Bruce F. McEwen ◽  
Karolyn F. Buttle ◽  
Conly L. Rieder
Keyword(s):  
Three Dimensional ◽  
Spindle Pole ◽  
The Other ◽  
Dimensional Electron ◽  
Laser Microsurgery ◽  
Electron Microscopic ◽  
Spindle Poles ◽  
Chromosome Congression ◽  
Chromosome Fragments ◽  
Multiple Domains

We used laser microsurgery to cut between the two sister kinetochores on bioriented prometaphase chromosomes to produce two chromosome fragments containing one kinetochore (CF1K). Each of these CF1Ks then always moved toward the spindle pole to which their kinetochores were attached before initiating the poleward and away-from-the-pole oscillatory motions characteristic of monooriented chromosomes. CF1Ks then either: (a) remained closely associated with this pole until anaphase (50%), (b) moved (i.e., congressed) to the spindle equator (38%), where they usually (13/19 cells) remained stably positioned throughout the ensuing anaphase, or (c) reoriented and moved to the other pole (12%). Behavior of congressing CF1Ks was indistinguishable from that of congressing chromosomes containing two sister kinetochores. Three-dimensional electron microscopic tomographic reconstructions of CF1Ks stably positioned on the spindle equator during anaphase revealed that the single kinetochore was highly stretched and/or fragmented and that numerous microtubules derived from the opposing spindle poles terminated in its structure. These observations reveal that a single kinetochore is capable of simultaneously supporting the function of two sister kinetochores during chromosome congression and imply that vertebrate kinetochores consist of multiple domains whose motility states can be regulated independently.

D-CAT: Density and Clustering Annotation Tool for three dimensional electron microscopic volumes

2012 ◽  
Vol 177 (2) ◽  
pp. 571-577 ◽  
Author(s):  
M.N. Lebbink ◽  
L.H.P. Hekking ◽  
W.J.C. Geerts ◽  
J.A. Post
Keyword(s):  
Three Dimensional ◽  
Annotation Tool ◽  
Dimensional Electron ◽  
Electron Microscopic
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