Microdensitometer—computer correlation analysis of ultrastructural periodicity

1978 ◽  
Vol 36 (2) ◽  
pp. 32-33
Author(s):  
D.R. Ensor ◽  
C.G. Jensen ◽  
J.A. Fillery ◽  
R.J.K. Baker
Keyword(s):  
Correlation Analysis ◽  
Background Noise ◽  
Computer Control ◽  
Optical Diffraction ◽  
Screw Thread ◽  
Straight Line ◽  
Computer Storage ◽  
Correlation Process ◽  
Electron Microscope Image ◽  
Fixed Beam

Because periodicity is a major indicator of structural organisation numerous methods have been devised to demonstrate periodicity masked by background “noise” in the electron microscope image (e.g. photographic image reinforcement, Markham et al, 1964; optical diffraction techniques, Horne, 1977; McIntosh,1974). Computer correlation analysis of a densitometer tracing provides another means of minimising "noise". The correlation process uncovers periodic information by cancelling random elements. The technique is easily executed, the results are readily interpreted and the computer removes tedium, lends accuracy and assists in impartiality.A scanning densitometer was adapted to allow computer control of the scan and to give direct computer storage of the data. A photographic transparency of the image to be scanned is mounted on a stage coupled directly to an accurate screw thread driven by a stepping motor. The stage is moved so that the fixed beam of the densitometer (which is directed normal to the transparency) traces a straight line along the structure of interest in the image.

scholarly journals What is a Good Way to Visualize the Positive Correlation between Two Numerical Variables?

2021 ◽  
Vol 3 (2) ◽  
pp. 24
Author(s):  
Heru Santoso Wahito Nugroho ◽  
Sanglar Polnok ◽  
Tanko Titus Auta ◽  
Ambo Dalle ◽  
Bahtiar Bahtiar ◽  
...  
Keyword(s):  
Correlation Analysis ◽  
Correlation Coefficient ◽  
Scatter Diagram ◽  
Research Projects ◽  
Positive Correlation ◽  
Valuable Lesson ◽  
Straight Line

Most of the results of correlation analysis between variables are not equipped with visualization, so it is deemed necessary to explain how best to visualize the results of correlation analysis, especially for numerical variables. In this case, the best way to present correlations between numerical variables is a scatter diagram. If the points on the diagram are closer to the straight line, the higher the correlation coefficient, meaning that the degree of correlation is getting stronger. In this case, the positive correlation is indicated by the line from the lower left to the upper right. This visualization helps clarify the reader's understanding of the results of the correlation analysis, as well as being a valuable lesson for their similar research projects. Keywords: positive correlation; correlation coefficient; visualization; scatter diagram

A simple graphic method to assess correlation

2021 ◽  
Vol 10 (1) ◽  
pp. 1-2
Author(s):  
Othmar W Winkler
Keyword(s):  
Correlation Analysis ◽  
Vertical Axis ◽  
Graphic Method ◽  
Data Set ◽  
Visual Appearance ◽  
Straight Line ◽  
Data Points ◽  
The Individual ◽  
Student Grades ◽  
Early English

This study explores the correlation between two variables and to demonstrate a simple graphic method to assess their degree of correlation. Following the lead of early English biometricians, it has been tacitly assumed that the studied variables develop in the same direction: when variable A’s measurements are higher from one object to another, the measurements of variable B, also are higher. The customary measure of co-relation relies on a least squares fitted trend line, then assuming that the trend is more real than, and has priority over the individually recorded data. The situation changes when measurements of variables develop in opposite directions: The very first data set I used to perform a correlation analysis was a study of student grades achieved and the percentage of their having missed classes: the more a student was absent from class, the lower were his achieved grades. In that situation the accepted model of correlation analysis – the mathematically fitted straight line and the squared distance of each student’s record from that line - was not appropriate. The usual correlation coefficient contradicted visual evidence of those data because the model underlying that situation treats the individual data as having more reality value than the general trend, but not as deviations or errors. The visual appearance, the graph of that situation, resembles a rectangular triangle, formed by the horizontal and vertical axis as its catheters, and the hypotenuse formed by a line through and representing the highest data points. This image justifies the expression “Triangular correlation”.

Development of a Hand-Arm Model to Emulate Tremor Handwriting Behavior

2014 ◽  
Vol 660 ◽  
pp. 911-915
Author(s):  
Zulkifli Mohd Yusop ◽  
Mohd Zarhamdy Md Zain ◽  
Mohamed Hussein ◽  
Maziah Mohamad
Keyword(s):  
Spectral Density ◽  
Hand Movement ◽  
Screw Thread ◽  
Frequency Range ◽  
Hand Tremor ◽  
Power Spectral ◽  
Straight Line ◽  
Acceleration Data ◽  
Model Setup ◽  
Handwriting Behavior

Patients with hand tremor may find difficulties in performing their routine task especially writing. The worse when the tremor becomes severe. In this paper, a hand-arm model has been developed to study the behavior of tremor while performing handwriting. Regarding the study, the hand of patient oscillates in a perpendicular direction to the forearm rather than other directions due to hand support while the handwriting is performed. A miniature accelerometer patched to the writing device and acceleration data recorded have then been examined by power spectral density (PSD). For hand-arm model setup, the DC motor was used to emulate the hand movement to draw a straight line by connecting the linear screw thread to the writing mechanism. For writing mechanism, there are two parts, holder to hold the pen and Linear Voice Coil Actuator (LVCA) to resemble hand tremor conditions. By injecting tremor data to the LVCA the acceleration is measured once again by attaching a miniature accelerometer to the writer device. The findings show that the model can emulates hand tremor by considering its acceleration and frequency range from PSD based on record actual tremor data as references. The hand-arm model furthers can be a research conduct to design a writing device that can be cancelled or at least suppress the tremor.

Dynamic Performance Analysis of Minimally Actuated 4-Bar Linkages for Upper Limb Rehabilitation

2015 ◽  
Author(s):  
Evagoras G. Xydas ◽  
Andreas Mueller
Keyword(s):  
Velocity Profile ◽  
Dynamic Performance ◽  
Computer Control ◽  
Human Robot Interaction ◽  
Upper Limb Rehabilitation ◽  
Kinematic Chains ◽  
Hand Motion ◽  
Straight Line ◽  
Non Linear ◽  
Dynamic Performance Analysis

In the last two decades robotic rehabilitation research provided insight regarding the human-robot interaction, helped understand the process by which the impaired nervous system is retrained to better control the hand motion, and led to the development of a number of mathematical and neurophysiological models that describe both the hand motion and the robot control. Now that this pool of knowledge is available, the respective models can be applied in a number of ways outside the robot domain, in which, machines are based on open kinematic chains with n-degrees of freedom (DOF’s) and sophisticated computer control, actuation and sensing. One such example is the use of mechanisms, closed kinematic chains which can still generate complex — yet specific — trajectories with fewer DOF’s. This paper further extends previous work on the design of such passive-active mechanisms that replicate the natural hand motion along a straight-line. The natural hand motion is described by a smooth bell-shaped velocity profile which in turn is generated by the well-established Minimum-Jerk-Model (MJM). Three different straight line 4-bar linkages, a Chebyshev’s, a Hoeken’s and a Watt’s, are examined. First, with the use of kinetostatic analysis and given the natural hand velocity and acceleration, the torque function of non-linear springs that act on the driving link is deduced. Then, given that the springs are acting, interaction with impaired users is considered and the extra actuation power that can maintain the natural velocity profile is calculated. A multibody dynamics software is employed for further assessing the mechanisms’ dynamic response under varying interaction forces. Also, different parameters like inertia are altered and the effects on internal (springs) and external (actuator) power are examined. Then, the three mechanisms are compared with respect to size, required amount of external power, ergonomic issues etc. Finally, it is investigated whether a linear fit of the non-linear spring torque can be adequate for generating the desired MJM trajectory and operate effectively in collaboration with the active part of the control.

Methods for Displaying Defocus and Astigmatism of High Resolution Stem Images

1980 ◽  
Vol 38 ◽  
pp. 64-65
Author(s):  
William Krakow
Keyword(s):  
High Resolution ◽  
High Speed ◽  
Computer Control ◽  
Carbon Film ◽  
Image Features ◽  
Objective Lens ◽  
Specimen Area ◽  
Beam Dose ◽  
Speed Computer ◽  
Fixed Beam

Focussing and stigmation of the objective lens for high resolution STEM imaging is usually achieved by repeated reduced area scans of a given specimen area under manual control of the instrument. This method is particularly laborious since the scan times for images can be upwards of several seconds which subjects a specimen to unwanted electron beam exposure. Methods have been proposed to optimize STEM images such as the use of shadow images1 where a fixed beam pattern for a highly defocussed objective lens is observed. This method again requires a high beam dose in a given specimen area. Alternately, if a white noise object such as a carbon film is used, granular image features without any directionality are desired. In this case the eye must integrate over a large number of small image features. A better alternative is the use computer control to digitize images in real time and compute the power spectrum of an image could be employed. This would require a dedicated high speed computer system for a 1000 × 1000 display, but this latter method would have the advantage that only a single scan of image is required.

Field trials with the LaCoste and Romberg straight‐line gravimeter

Geophysics ◽  
1983 ◽  
Vol 48 (5) ◽  
pp. 611-617 ◽  
Author(s):  
H. D. Valliant
Keyword(s):  
Correlation Analysis ◽  
Field Tests ◽  
Cross Coupling ◽  
Field Trials ◽  
Coupling Effects ◽  
Straight Line ◽  
Corrected Data ◽  
Correlation Techniques ◽  
The Cross

During field tests in 1980, the prototype of the LaCoste and Romberg straight‐line gravimeter (ser. no. SL-1) generally produced gravity values intermediate between those of two comparison “S” meters (ser. nos. S-56 and S-41). Correlation analysis shows that the data from SL-1 with no cross‐coupling correction are 15 percent smoother even in rough weather than the corrected data from either S meter. When corrections to the cross‐coupling effects are applied through postcruise correlation techniques, the curvature (degree of smoothness) of the respective data agrees to within 2 percent for each meter. These results verify that cross‐coupling errors have been virtually eliminated in the new gravimeter.

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Freeze fracture imaging and computer simulation of liposome structure: Membrane geometry and defects

1983 ◽  
Vol 41 ◽  
pp. 646-647
Author(s):  
Joseph A. Zasadzinski
Keyword(s):  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Continuum Theory ◽  
Closed Surfaces ◽  
Straight Line ◽  
Low Weight ◽  
Concentric Spheres ◽  
Membrane Geometry ◽  
Dupin Cyclides ◽  
Limiting Case

At low weight fractions, many surfactant and biological amphiphiles form dispersions of lamellar liquid crystalline liposomes in water. Amphiphile molecules tend to align themselves in parallel bilayers which are free to bend. Bilayers must form closed surfaces to separate hydrophobic and hydrophilic domains completely. Continuum theory of liquid crystals requires that the constant spacing of bilayer surfaces be maintained except at singularities of no more than line extent. Maxwell demonstrated that only two types of closed surfaces can satisfy this constraint: concentric spheres and Dupin cyclides. Dupin cyclides (Figure 1) are parallel closed surfaces which have a conjugate ellipse (r1) and hyperbola (r2) as singularities in the bilayer spacing. Any straight line drawn from a point on the ellipse to a point on the hyperbola is normal to every surface it intersects (broken lines in Figure 1). A simple example, and limiting case, is a family of concentric tori (Figure 1b).To distinguish between the allowable arrangements, freeze fracture TEM micrographs of representative biological (L-α phosphotidylcholine: L-α PC) and surfactant (sodium heptylnonyl benzenesulfonate: SHBS)liposomes are compared to mathematically derived sections of Dupin cyclides and concentric spheres.

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