Arrow Plot Research Articles

Quantitative Analysis by 3D Graphics of Thoraco-Abdominal Surface Shape and Breathing Motion

Chest wall motion can provide information on respiratory muscles' action and on critical vital signs, like respiration and cardiac activity. The chest wall is a structure with three compartments that are independent to each other and can move paradoxically according to the pathophysiology of the disease. Opto-electronic plethysmography (OEP) allows for non-invasively 3D tracking of body movements. We aimed to extend the characteristics of OEP analysis to local analyses of thoraco-abdominal surface geometry and kinematics during respiration. Starting from the OEP output file, the 3D markers’ coordinates were combined with a triangulation matrix. A smoothing procedure (an automatic and iterative interpolation process to increase the number of vertices from 93 to 548) was applied to allow for precise local analysis of the thoraco-abdominal surface. A series of measurements can be performed to characterize the geometry of the trunk and its three compartments, in terms of volumes, height, diameters, perimeters, and area. Some shape factors, such as surface-to-volume ratio or height-to-perimeter ratio, can be also computed. It was also possible to build the vector field associated with the breathing motion of all the vertices, in terms of magnitude and motion direction. The vector field data were analyzed and displayed through two graphic tools: a 3D heatmap, in which the magnitude of motion was associated to different colors, and a 3D arrow plot, that allowed us to visualize both the magnitude and the direction of motion with color-coded arrows. The methods were applied to 10 healthy subjects (5 females) and also applied to two cases: a pregnant woman at each trimester of gestation and a patient before and after a demolition thoracic surgery. The results proved to be coherent with the physiology of healthy subjects and the physiopathology of the cases. We developed a new non-invasive method for respiratory analysis that allowed for the creation of realistic 3D models of the local and global trunk surface during respiration. The proposed representation constituted a very intuitive method to visualize and compare thoraco-abdominal surface movements within and between subjects, therefore enforcing the potential clinical translational value of the method.

Computational Analysis of Enhanced Circulating Tumour Cell (CTC) Separation in a Microfluidic System with an Integrated Dielectrophoretic-Magnetophorectic (DEP-MAP) Technique

Cell based cancer analysis is an important analytic method to monitor cancer progress on stages by detecting the density of circulating tumour cells (CTCs) in the blood. Among the existing microfluidic techniques, dielectrophoresis (DEP), which is a label-free detection method, is favoured by researchers. However, because of the high conductivity of blood as well as the rare presence of CTCs, high separation efficiency is difficult to achieve in most DEP microdevices. Through this study, we have proposed a strategy to improve the isolation performance, as such by integrating a magnetophoretic (MAP) platform into a DEP device. Several important aspects to be taken into MAP design consideration, such as permanent magnet orientation, magnetic track configuration, fluid flow parameter and separation efficiency, are discussed. The design was examined and validated by numerical simulation using COMSOL Multiphysics v4.4 software (COMSOL Inc., Burlington, MA, USA), mainly presented in three forms: surface plot, line plot, and arrow plot. From these results, we showed that the use of a single permanent magnet coupled with an inbuilt magnetic track of 250 μm significantly strengthens the magnetic field distribution within the proposed MAP stage. Besides, in order to improve dynamic pressure without compromising the uniformity of fluid flow, a wide channel inlet and a tree-like network were employed. When the cell trajectory within a finalized MAP stage is computed with a particle tracing module, a high separation efficiency of red blood cell (RBC) is obtained for blood samples corresponding up to a dilution ratio of 1:7. Moreover, a substantial enhancement of the CTCs’ recovery rate was also observed in the simulation when the purposed platform was integrated with a planar DEP microdevice.

Scan path entropy and arrow plots: capturing scanning behavior of multiple observers

Designers of visual communication material want their material to attract and retain attention. In marketing research, heat maps, dwell time, and time to AOI first hit are often used as evaluation parameters. Here we present two additional measures (1) “scan path entropy” to quantify gaze guidance and (2) the “arrow plot” to visualize the average scan path. Both are based on string representations of scan paths. The latter also incorporates transition matrices and time required for 50% of the observers to first hit AOIs (T50). The new measures were tested in an eye tracking study (48 observers, 39 advertisements). Scan path entropy is a sensible measure for gaze guidance and the new visualization method reveals aspects of the average scan path and gives a better indication in what order global scanning takes place.

Arrow plot: a new graphical tool for selecting up and down regulated genes and genes differentially expressed on sample subgroups

BackgroundA common task in analyzing microarray data is to determine which genes are differentially expressed across two (or more) kind of tissue samples or samples submitted under experimental conditions. Several statistical methods have been proposed to accomplish this goal, generally based on measures of distance between classes. It is well known that biological samples are heterogeneous because of factors such as molecular subtypes or genetic background that are often unknown to the experimenter. For instance, in experiments which involve molecular classification of tumors it is important to identify significant subtypes of cancer. Bimodal or multimodal distributions often reflect the presence of subsamples mixtures. Consequently, there can be genes differentially expressed on sample subgroups which are missed if usual statistical approaches are used. In this paper we propose a new graphical tool which not only identifies genes with up and down regulations, but also genes with differential expression in different subclasses, that are usually missed if current statistical methods are used. This tool is based on two measures of distance between samples, namely the overlapping coefficient (OVL) between two densities and the area under the receiver operating characteristic (ROC) curve. The methodology proposed here was implemented in the open-source R software.ResultsThis method was applied to a publicly available dataset, as well as to a simulated dataset. We compared our results with the ones obtained using some of the standard methods for detecting differentially expressed genes, namely Welch t-statistic, fold change (FC), rank products (RP), average difference (AD), weighted average difference (WAD), moderated t-statistic (modT), intensity-based moderated t-statistic (ibmT), significance analysis of microarrays (samT) and area under the ROC curve (AUC). On both datasets all differentially expressed genes with bimodal or multimodal distributions were not selected by all standard selection procedures. We also compared our results with (i) area between ROC curve and rising area (ABCR) and (ii) the test for not proper ROC curves (TNRC). We found our methodology more comprehensive, because it detects both bimodal and multimodal distributions and different variances can be considered on both samples. Another advantage of our method is that we can analyze graphically the behavior of different kinds of differentially expressed genes.ConclusionOur results indicate that the arrow plot represents a new flexible and useful tool for the analysis of gene expression profiles from microarrays.

Dipmeter Advisor Expert System: ABSTRACT

The dipmeter services offered by Schlumberger consist of measurements made in a well bore to determine the inclinations, or dip, of the bedding layers penetrated by the well. The measurements are represented on a log in the form of arrow plots, which indicate the magnitude and direction of the dip as a function of depth. Information about the underground structure and stratigraphy can be derived from arrow plot patterns on the dipmeter log in conjunction with other types of data from the borehole as well as some general knowledge of the geological area. Traditionally, interpretation of dipmeter data has been made by a human expert who identifies and decodes the arrow plot patterns. The Dipmeter Advisor system is an application of artificial intelligence and expert system techniques to dipmeter log interpretation. End_Page 1703------------------------------ It incorporates the inference and knowledge of human dipmeter experts. The first prototype system, which was completed in December 1980, consisted of interpretation in marine environments, but recently the system has been extended to continental and transitional environments as well. The Dipmeter Advisor system has a highly interactive graphics user interface. During the interpretation, the user has access to the arrow plot data and other related well data through a graphics display screen. The interpretation is made in a sequence of passes over the data, each pass arriving at some conclusions based on user input, combined with applications of the rules of dipmeter interpretation and of pattern recognition algorithms in previous passes. The partial results are displayed on the graphics screen for user verification and the user can, with graphics interaction devices, make any additions, deletions, and modifications of the results in each pass. The final output of the system consists of a log annotated much in the same way as dipmeter logs are currently annotated by human experts. Several aspects of the Dipmeter Advisor system will be described: the system organization, the graphics interface, and the general form of the rules and the inference structure. The operation of the Dipmeter Advisor system will be demonstrated with an example of dipmeter interpretation. End_of_Article - Last_Page 1704------------

Eddy current calculations for thin cylinders of finite length with driving fields of ramp time dependence

Eddy current density for a thin cylinder of finite length is calculated for the case of a driving field of ramp time dependence and dipole spatial dependence, the dipole being at the center of the cylinder. The calculations are made by using a perturbation expansion of the eddy current integral equations with a polynomial approximation to the time factor of the driving term. The steady state solution, presented as an arrow plot, shows the effects of edge charges forcing currents to remain within the conductor. The transient solutions show that the entire geometrical pattern of the steady state eddy currents is approached uniformly in the typical exponential manner of diffusion equations. Typical transient curves are given. All calculations are in normalized coordinates to allow maximum flexibility in applications.