Single-particle electron microscopy (EM) has been shown to be very powerful for studying structures and associated conformational changes of macromolecular complexes. In the context of analyzing conformational changes of complexes, distinct EM density maps obtained by image analysis and three-dimensional (3D) reconstruction are usually analyzed in 3D for interpretation of structural differences. However, graphic visualization of these differences based on a quantitative analysis of elastic transformations (deformations) among density maps has not been done yet due to a lack of appropriate methods. Here, we present an approach that allows such visualization. This approach is based on statistical analysis of distances among elastically aligned pairs of EM maps (one map is deformed to fit the other map), and results in visualizing EM maps as points in a lower-dimensional distance space. The distances among points in the new space can be analyzed in terms of clusters or trajectories of points related to potential conformational changes. The results of the method are shown with synthetic and experimental EM maps at different resolutions.
The recent successes of cryo-electron microscopy fostered great expectation of solving many new and previously recalcitrant biomolecular structures. However, it also brings with it the danger of compromising the validity of the outcomes if not done properly. The Map Challenge is a first step in assessing the state of the art and to shape future developments in data processing. The organizers presented seven cases for single particle reconstruction, and 27 members of the community responded with 66 submissions. Seven groups analyzed these submissions, resulting in several assessment reports, summarized here. We devised a range of analyses to evaluate the submitted maps, including visual impressions, Fourier shell correlation, pairwise similarity and interpretation through modeling. Unfortunately, we did not find strong trends. We ascribe this to the complexity of the challenge, dealing with multiple cases, software packages and processing approaches. This puts the user in the spotlight, where his/her choices becomes the determinant of map quality. The future focus should therefore be on promulgating best practices and encapsulating these in the software. Such practices include adherence to validation principles, most notably the processing of independent sets, proper resolution-limited alignment, appropriate masking and map sharpening. We consider the Map Challenge to be a highly valuable exercise that should be repeated frequently or on an ongoing basis.
This document presents the analysis performed over the Map Challenge dataset using a new algorithm which we refer to as Pair Comparison Method. The new algorithm, which is described in detail in the text, is able to sort reconstructions based on a figure of merit and assigns a level of significance to the sorting. That is, it shows how likely the sorting is due to chance or if it reflects real differences.
Purpose This paper aims to analyze the influence of the changings in geometrical parameters on the aerodynamic performance of the control canard projectiles. Design/methodology/approach Because of the mentioned point, the range of projectiles increment has a considerable importance, and the design algorithm of a control canard projectile was first written. Then, were studied the effects of canard geometric parameters such as aspect ratio, taper ratio and deflectable nose on lift to drag coefficient ratio, static margin based on the slender body theory and cross section flow. Findings The code results show that aspect ratio increment, results in an increase in lift-to-drag ratio of the missile, but increase in canard taper ratio results in increasing of lift-to-drag ratio at 1° angle of attack, while during increasing the canard taper ratio up to 0.67 at 4° angle of attack, lift to drag first reaches to maximum and then decreases. Also, static margin decreases with canard taper ratio and aspect ratio increment. The developed results for this type of missile were compared with same experimental and computational fluid dynamic (CFD) results and appreciated agreement with other results at angles of attack between 0° and 6°. Practical implications To design a control canard missile, the effect of each geometric parameter of canard needs to be estimated. For this purpose, the suitable algorithm is used. In this paper, the effects of canard geometric parameters, such as aspect ratio, taper ratio and deflectable nose on lift-to-drag coefficient ratio and static margin, were studied with help of the slender body theory and cross-section flow. Originality/value The contribution of this paper is to predict the aerodynamic characteristics for the control canard missile. In this study, the effect of the design parameter on aerodynamic characteristics can be estimated, and the effect of geometrical characteristics has been analyzed with a suitable algorithm. Also, the best lift-to-drag coefficient for the NASA Tandem Control Missile at Mach 1.75 was selected at various angles of attack. The developed results for this type of missile were compared with same experimental and CFD results.
In this paper, an analysis of capnogram to differentiate asthmatic and non-asthmatic patients is presented by using linear predictive coding (LPC) technique. In the previous studies, manual study on capnogram signal has been conducted by several researchers. All previous researches show significant correlation between the capnogram and asthmatic patient. However all of them are just manual study conducted through the conventional time domain method. In this preliminary, a number of 8 LPC coefficients (α 1 -α 8 ) for both asthmatic (CAP) and non-asthmatic patients' capnogram (CNP) are extracted. Usefulness and performance of these coefficients to differentiate the asthmatic conditions by means of receiver operating characteristic (ROC) curve analysis are shown. Our preliminary results show that α 3 , α 4 , α 5 , and α 6 can be used to distinguish the asthmatic conditions.
This paper is an investigation of the role of the robust control strategy of the rear wheel steer system to improve handling. To establish an accurate model of the vehicle, a nine degree-of-freedom (DOF) model is considered. The model's degrees of freedom consist of three angular motions (roll, pitch, and yaw) of the sprung mass, spin of the wheels, and two translational motions (forward and side travel) of the unsprung mass. Also, the environment and geometric effects, such as aerodynamic forces, tyre-ground interaction, body roll versus camber relation, steering command saturation, and roll axis inclination, are taken into account. The front and rear suspensions are assumed to be a MacPherson strut and semi-trailing arm respectively. Cornering behaviour of the vehicle is studied and compared for a manual two-wheel steer (2WS) and a sliding-mode control assisted four-wheel steer (4WS) vehicle. A 3-DOF vehicle model is used to make a fast state estimation. The yaw rate is used as the reference signal for the control system, to ensure that the desired handling is obtained. The results show that during the standard cornering manoeuvres, the sliding-mode control provides significant tracking performance and lower sensitivity to vehicle velocity, road condition, and roll axis inclination compared to the 2WS. Also lane tracking and cornering behaviour of the steering system is enhanced towards the neutral steer.
Macromolecular structural determination by Electron Microscopy under cryogenic conditions is revolutionizing the field of structural biology, interesting a large community of potential users. Still, the path from raw images to density maps is complex, and sophisticated image processing suites are required in this process, often demanding the installation and understanding of different software packages. Here, we present Scipion Web Tools, a web-based set of tools/workflows derived from the Scipion image processing framework, specially tailored to nonexpert users in need of very precise answers at several key stages of the structural elucidation process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.