scholarly journals Improving the field homogeneity of fixed- and variable-diameter discrete Halbach magnet arrays for MRI via optimization of the angular magnetization distribution

2021 ◽  
Vol 324 ◽  
pp. 106923
Author(s):  
Sumit Tewari ◽  
Thomas O'Reilly ◽  
Andrew Webb
Keyword(s):  
Magnetization Distribution ◽  
Variable Diameter ◽  
Field Homogeneity

Ultrastructure of bronchopulmonary lavage cells from bovines administered 3-methylindole: II. 24 hours post-treatment

1984 ◽  
Vol 42 ◽  
pp. 202-203
Author(s):  
Amreek Singh ◽  
Judith M. McLaren ◽  
Onkar S. Atwal ◽  
Peter Eyre
Keyword(s):  
Plasma Cells ◽  
Ciliated Cell ◽  
Lavage Fluid ◽  
Treated Group ◽  
Post Treatment ◽  
Lung Edema ◽  
Ciliated Cells ◽  
Thin Sections ◽  
Variable Diameter ◽  
Cell Pellet

Introduction3-methylindole (MI), a rumen metabolite of the amino acid L-tryptophan, has been shown to produce bovine pulmonary edema and emphysema. The airways contain free and exfoliated cells. A morphologic analysis of these cells may complement the understanding of the mechanism of lung edema. Ultrastructure of the bronchopulmonary lavage (BL) cells 24 h following MI oral administration to calves is described in this experiment. The 12 hours post-treatment results were described earlier.Materials and MethodsTwo Holstein-Friesian calves were each administered an oral dose of 0.2 g MI/Kg body weight and another two calves served as controls. The animals were euthanized with sodium pentabarbitol 24 h after receiving the compound. The lungs and trachea were removed and 0.1 M sodium phosphate buffered saline was infused into the lungs through the trachea. Glutaraldehyde fixative was added to the recovered BL fluid so as to form a 1% solution. The fluid was centrifuged and the resulting cell pellet was suspended in the buffer. The procedures were repeated on the suspension; the pellet was post-fixed in osmium tetroxide and was processed by conventional methods of section preparations for TEM examination. Lung samples from caudal lobes were fixed in 1.5% glutaraldehyde to obtain tissue sections for TEM.Results and DiscussionPulmonary alveolar macrophages (AM), neutrophils, ciliated epithelial cells, globule leukocytes and plasma cells were recovered from the BL fluid of the control and Mi-administered calves. Ciliated cells and globule leukocytes could not be harvested from the controls. The AM obtained from the treated calves (Fig. 1) in comparison with similar cells from the controls were larger, and contained large membrane-limited inclusions (phagolysosomes). There was a remarkable similarity between the lavaged AM and the AM studied in thin sections of lung (cf. Fig. 1 and Fig. 2). The neutrophil was the second most abundant cell type retrieved from the lavage fluid from the calves of control or treated group. Except for scanty pseudopodia in the neutrophils obtained from the Mi-receiving calves, the cells appeared unaltered (Fig. 3). Ciliated cells were abundant in the BL fluid of Mi-ingesting calves. A heterogeneous collection of vesicles filled the ciliated cell cytoplasm (Fig. 3). Globule leukocytes were commonly observed among BL cells of treated calves. The globule leukocytes were ca. 15 μm in diameter and contained round or elliptical nuclei with conspicuous nucleoli. The cytoplasmic granules, which are a prominent feature of globule leukocytes, were electron-opaque and had a variable diameter (0.5-3.0 μm). A one-line account of globule leukocytes in the bronchi of steers administered MI has appeared. Plasma cells were rare. Ultrastructure of BL cells is compatible with their response to chemical insult by MI.

Quantitative Diameter Measurements of Chromatin and TMV Fibers in the Freeze-Dried State

1988 ◽  
Vol 46 ◽  
pp. 170-171
Author(s):  
B. D. Athey ◽  
A. L. Stout ◽  
M. F. Smith ◽  
J. P. Langmore
Keyword(s):  
Reliable Method ◽  
Fiber Diameter ◽  
Quantitative Agreement ◽  
One Dimension ◽  
Fiber Axis ◽  
Two Dimensional ◽  
Fiber Density ◽  
Variable Diameter ◽  
Freeze Dried ◽  
Expected Values

Although there is general agreement that Inactive chromosome fibers consist of helically packed nucleosomes, the pattern of packing is still undetermined. Only one of the proposed models, the crossed-linker model, predicts a variable diameter dependent on the length of DNA between nucleosomes. Measurements of the fiber diameter of negatively-stained and frozen- hydrated- chromatin from Thyone sperm (87bp linker) and Necturus erythrocytes (48bp linker) have been previously reported from this laboratory. We now introduce a more reliable method of measuring the diameters of electron images of fibrous objects. The procedure uses a modified version of the computer program TOTAL, which takes a two-dimensional projection of the fiber density (represented by the micrograph itself) and projects it down the fiber axis onto one dimension. We illustrate this method using high contrast, in-focus STEM images of TMV and chromatin from Thyone and Necturus. The measured diameters are in quantitative agreement with the expected values for the crossed-linker model for chromatin structure

Influence of the residual quenching stresses on the magnetization distribution in amorphous ferromagnetic wires

1998 ◽  
Vol 08 (PR2) ◽  
pp. Pr2-207-Pr2-210 ◽  
Author(s):  
N. A. Usov ◽  
A. C. Antonov ◽  
A. M. Dykhne ◽  
S. E. Peschany ◽  
A. N. Lagar'kov
Keyword(s):  
Magnetization Distribution

Main Provisions Of The Concept Of Technology Of Diamond Cutting And Drilling Of Building Structures

2019 ◽  
pp. 59-63
Keyword(s):  
Combustion Engine ◽  
Front Surface ◽  
The Body ◽  
Building Structures ◽  
Diamond Cutting ◽  
Variable Diameter ◽  
Diamond Drilling ◽  
Single Structure ◽  
New Construction ◽  
Non Destructive

The main provisions of the concept of technology of diamond cutting and drilling of building structures are considered. The innovativeness of the technology, its main possibilities and advantages are presented. Carrying out works with the help of this technology in underwater conditions expands its use when constructing and reconstructing hydraulic structure. The use of diamond drilling equipment with motors equipped with an internal combustion engine is considered. Drilling holes with a variable diameter during the reconstruction of the runways of airfields makes it possible to combine the landing mats into a single structure. The ability to cut inside the concrete mass, parallel to the front surface, has no analogues among the methods of concrete treatment. The use of this technology for producing blind openings in the body of concrete without weakening the structure is also unique. Work with precision quality in cutting and diamond drilling of concrete and reinforced concrete was noted by architects and began to be implemented in the manufacture of inter-room and inter-floor openings. Non-destructive approach to the fragmentation of building structures allows them to be reused. The technology of diamond cutting and drilling is located at the junction of new construction, repair, reconstruction of buildings and structures, and dismantling of structures. Attention is paid to the complexity and combinatorial application of diamond technology. Economic efficiency and ecological safety of diamond technology are presented. The main directions of further research for the development of technology are indicated.

scholarly journals Design and performance test of variable diameter threshing drum of combine harvester

2021 ◽  
Author(s):  
Zhan Su ◽  
Zhao Ding ◽  
Liquan Tian ◽  
Xue Lin ◽  
Zhiming Wang
Keyword(s):  
Performance Test ◽  
Variable Diameter ◽  
Combine Harvester ◽  
And Performance

scholarly journals Multidisciplinary Approach to Suspected Sudden Death Caused by Arteriovenous Malformation Rupture: A Case Report

Medicina ◽  
2021 ◽  
Vol 57 (7) ◽  
pp. 644
Author(s):  
Federico Giuseppe Patanè ◽  
Massimiliano Esposito ◽  
Andrea Giovanni Musumeci ◽  
Monica Palermo ◽  
Marco Torrisi ◽  
...  
Keyword(s):  
Arteriovenous Malformation ◽  
Cause Of Death ◽  
Venous Malformation ◽  
Healthy Woman ◽  
Unexpected Death ◽  
Medical Problems ◽  
Variable Diameter ◽  
Life Threatening ◽  
Brain Avms ◽  
The Brain

Arteriovenous malformations (AVMs) are rare congenital conditions with a prevalence of less than 1% and are mostly asymptomatic. However, these malformations can suddenly cause intense pain or bleeding, leading to life-threatening medical problems. This report presents a case of an unexpected death in a 37-year-old previously healthy woman due to an intra-cerebellum arteriovenous malformation rupture identified during autopsy. While infective processes where preliminarily excluded, a Post Mortem Computed Tomography (PMCT) identified a tetra ventricular hemorrhage and intra-cerebellum hemorrhage. Toxicological examination was negative for most substances of abuse. During autopsy an intense hemorrhagic infiltrate in the subarachnoid space was observed. After formalin fixation of the brain the cerebellum showed hemorrhagic infarction on fourth ventricle sides, as well as several small reddish infarctions across the entire cerebellum parenchyma. Histological examination of the brain and cerebellum showed a suffusion of erythrocytes in the sub-arachnoid region. Evidence of an arterio-venous malformation, with several intertwine vessels of variable diameter, surrounded by hemorrhagic evidence. The autopsy played a crucial role in identifying the location and the possibly affected vessel, as well as defining the cause of death. It is necessary to have a greater number of autopsies to make an epidemiological contribution. Furthermore, it is crucial to create a multicenter data network with other authors from other departments to improve information about epidemiological, clinical, diagnostic and therapeutic data. Most brain AVMs as cause of death are often undiscovered.

A Least Square Method for Measurement and Optimisation in Selected Physical Experiments

2005 ◽  
Vol 295-296 ◽  
pp. 681-686 ◽  
Author(s):  
I. Frollo ◽  
P. Andris ◽  
I. Strolka ◽  
L. Bačiak
Keyword(s):  
Magnetic Field ◽  
Input Parameter ◽  
Target Function ◽  
Least Square Method ◽  
Least Square ◽  
Physical Experiments ◽  
Magnetic Field Homogeneity ◽  
Field Homogeneity ◽  
Basic Parameters ◽  
Shim Coils

The scope of this paper is to demonstrate a least square method for optimisation of basic parameters for selected physical experiment design where large input parameter measurement and adjustment is needed. The speed of calculation and experimentally verified results are promising to use this method in many physical projects. We have demonstrated this method for computation of feeding currents of correcting coils for stationary magnetic field used in NMR imaging. A set of linear equation definition and determination of a target function and optimisation computations are presented with procedures that provide optimal values of currents for shim coils. The proposed method, because of its simplicity and speed of computation, is convenient for basic adjustment of the magnetic field homogeneity by the first magnet installation. It is also suitable for periodic testing and magnet inhomogeneity correction for MRI magnets.

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