Three-dimensional structural analysis of the group B polysaccharide of Neisseria meningitidis 6275 by two-dimensional NMR: the polysaccharide is suggested to exist in helical conformations in solution

Biochemistry ◽  
1991 ◽  
Vol 30 (3) ◽  
pp. 851-857 ◽  
Author(s):  
Ryohei Yamasaki ◽  
Bradley Bacon
Keyword(s):  
Structural Analysis ◽  
Neisseria Meningitidis ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Group B

“Exact” Three-Dimensional Linear and Nonlinear Seismic Analysis of Structures with Two-Dimensional Models

2003 ◽  
Vol 19 (4) ◽  
pp. 897-912 ◽  
Author(s):  
Michael Mehrain ◽  
Farzad Naeim
Keyword(s):  
Structural Analysis ◽  
Nonlinear Analysis ◽  
Seismic Analysis ◽  
Three Dimensional ◽  
Modeling Technique ◽  
Two Dimensional ◽  
Single Model ◽  
Relative Ease ◽  
Conventional Analysis ◽  
Linear And Nonlinear

This paper presents a modeling technique by which a complete three-dimensional (3-D) structural analysis of a structure can be performed using two-dimensional (2-D) models, and hence 2-D software. The approach includes the effect of torsion, walls perpendicular and inclined to the direction of motion as well as walls with L, T, and H shapes in plan. Diaphragm displacements are easily modeled. The method can be used with linear and nonlinear analysis. Nonlinearity in the diaphragms can also be modeled with relative ease. Furthermore, unlike the conventional analysis that requires two 2-D models, one in each direction of motion, to model the 3-D structure, this approach requires only a single model.

scholarly journals Comparison of Morphologic Parameters of Temporomandibular Joint for Asymptomatic Subjects Using the Two-Dimensional and Three-Dimensional Measuring Methods

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yuanli Zhang ◽  
Xianchao Xu ◽  
Zhan Liu
Keyword(s):  
Temporomandibular Joint ◽  
Three Dimensional ◽  
Measuring Method ◽  
3D Models ◽  
Joint Space ◽  
Two Dimensional ◽  
Group A ◽  
Group B ◽  
Asymptomatic Subjects ◽  
Method Group

The differences of temporomandibular joint (TMJ) morphologic parameters by using two-dimensional (2D) and three-dimensional (3D) measuring methods were compared. Ten asymptomatic subjects (26.75 ± 4.89 years) were randomly recruited. The 3D models of the maxilla, mandible, and teeth were reconstructed according to cone-beam computed tomography (CBCT) image data. The morphologic parameters of TMJs were measured by the 2D CBCT measuring method (group A) and the 3D reconstruction model measuring method (group B), respectively. The morphologic parameters in each group were assessed by paired samplest-test, and the statistical significance was achieved whenp<0.05. The horizontal condylar angle (HCA), sagittal ramus angle (SRA), medial joint space (MJS), lateral joint space (LJS), superior joint space (SJS), and anterior joint space (AJS) in group A were significantly smaller than those in group B (p<0.05). The HCA on the left side was significantly smaller than that on the right side in group A (p<0.05). However, all the morphologic parameters in group B were not significantly different between left and right sides. In conclusion, there were significant differences for the morphologic parameters of TMJ measured on 2D CBCT and 3D models. 3D measuring method should be used for the detection of TMJ morphology in clinical practice.

A method for the derivation of load effect envelopes based on statistical considerations

1993 ◽  
Vol 20 (2) ◽  
pp. 201-209
Author(s):  
Eugene J. O'Brien ◽  
Robert E. Loov
Keyword(s):  
Structural Analysis ◽  
Three Dimensional ◽  
Elastic Analysis ◽  
Two Dimensional ◽  
Statistical Parameters ◽  
Simple Method ◽  
Load Effect ◽  
Linear Elastic ◽  
Derived Design ◽  
Usual Process

A simple method is proposed as a substitute for the usual process of factoring loads, performing a linear elastic analysis, and determining an envelope of the results. The method is based on statistical principles, but only a minimum knowledge of statistics is required for its use. It involves conventional structural analysis followed by some processing of the results which could readily be incorporated into existing computer programs.The practice of performing two-dimensional analyses on parts of three-dimensional structures is possible with the proposed approach. The implications are clarified and the necessary statistical parameters are derived.Deterministically derived design envelopes represent all the extremes of loading that can reasonably be considered. The envelopes found by the new method not only reflect loading variations but also consider their relative probabilities of occurrence so that excursions beyond the envelope are expected to be equally infrequent along the entire length of the structure. Inconsistencies inherent in the conventional approach are highlighted by comparison with the proposed method for a number of examples. Key words: probabilistic, safety, load, imposed load, load effect envelope, building.

Modified Wavelet-Based Multilevel Discrete-Continual Finite Element Method for Local Structural Analysis - Part 1: Continual and Discrete-Continual Formulations of the Problems

2014 ◽  
Vol 670-671 ◽  
pp. 720-723 ◽  
Author(s):  
Pavel A. Akimov ◽  
Marina L. Mozgaleva ◽  
Mojtaba Aslami ◽  
Oleg A. Negrozov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Three Dimensional ◽  
Accurate Solution ◽  
Geometrical Parameters ◽  
Two Dimensional ◽  
Boundary Problems ◽  
Piecewise Constant ◽  
Element Method

The distinctive paper is devoted to wavelet-based discrete-continual finite element method (WDCFEM) of structural analysis. Two-dimensional and three-dimensional problems of analysis of structures with piecewise constant physical and geometrical parameters along so-called “basic” direction are under consideration. High-accuracy solution of the corresponding problems at all points of the model is not required normally, it is necessary to find only the most accurate solution in some pre-known local domains. Wavelet analysis is a powerful and effective tool for corresponding researches. Initial continual and discrete-continual formulations of multipoint boundary problems of two-dimensional and three-dimensional structural analysis are presented.

Modified Wavelet-Based Multilevel Discrete-Continual Finite Element Method for Local Structural Analysis - Part 2: Reduced Formulations of the Problems in Haar Basis

2014 ◽  
Vol 670-671 ◽  
pp. 724-727 ◽  
Author(s):  
Pavel A. Akimov ◽  
Marina L. Mozgaleva ◽  
Mojtaba Aslami ◽  
Oleg A. Negrozov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Analysis ◽  
Three Dimensional ◽  
Haar Wavelet ◽  
Wavelet Basis ◽  
Two Dimensional ◽  
Governing Equations ◽  
Boundary Problems ◽  
Element Method

The distinctive paper is devoted to wavelet-based discrete-continual finite element method (WDCFEM) of structural analysis. Discrete-continual formulations of multipoint boundary problems of two-dimensional and three-dimensional structural analysis are transformed to corresponding localized formulations by using the discrete Haar wavelet basis and finally, with the use of averaging and reduction algorithms, the localized and reduced governing equations are obtained. Special algorithms of localization with respect to each degree of freedom are presented.

A Comparison of the Use of Two-Dimensional and Three-Dimensional Visualization Systems by Novice and Experienced Microsurgeons in Microsurgical Vessel Anastomosis: An Analysis Using the Chicken Model

2021 ◽  
Author(s):  
Wen-Chien Wang ◽  
Hsiang-Wei Hu ◽  
Pedro Ciudad ◽  
Bor-Shyh Lin ◽  
Hung-Chi Chen ◽  
...  
Keyword(s):  
3D Visualization ◽  
Three Dimensional ◽  
Image Resolution ◽  
Field Of View ◽  
Two Dimensional ◽  
Visualization System ◽  
Operator Experience ◽  
Group A ◽  
Group B ◽  
2D And 3D

Abstract Background Various studies have discussed the benefits of applying three-dimensional (3D) techniques, specifically its advantages with respect to ergonomics, feasibility, and the rate of learning achievable in microsurgery training. However, no study has been conducted that compares the operator experience of using two-dimensional (2D) and 3D systems in microsurgical training. The aim of this study is to compare 2D- and 3D-assisted microsurgical training in novices based on anastomosis of chicken femoral arteries. Methods The participants were grouped by previous microsurgical experience. Group A includes novice participants. Group B includes 2D-experienced participants. Group C includes both participants in groups A and B. A questionnaire composed of 10 parameters in the field of image quality, dexterity, ergonomic, and feasibility will be filled out after each participant finished their anastomoses by the 2D and 3D systems. Results The results demonstrated 3D system was scored better on “field of view” (p = 0.004), “less tremor” (p = 0.005), “neck/upper back comfort” (p = 0.043), “lower back comfort” (p = 0.015), “technical feasibility” (p = 0.020), and “educational feasibility” (p = 0.004) in group A (N = 12). In group B (N = 9), 3D system was scored better on “field of view” (p = 0.041) but worse on “image resolution” (p = 0.031). Conclusion With the 3D visualization system for microsurgical anastomosis of chicken femoral model, there are significant improvements in the field of view, stability, ergonomics, and educational value compared with 2D system among all participants. Accordingly, 3D-assisted microsurgery training can be a novel and potential popular training method.

Two-dimensional nuclear magnetic resonance at 500 MHz: the structural elucidation of a Salmonella serogroup N polysaccharide antigen

1986 ◽  
Vol 64 (2) ◽  
pp. 255-264 ◽  
Author(s):  
David R. Bundle ◽  
Manfred Gerken ◽  
Malcolm B. Perry
Keyword(s):  
Structural Analysis ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Model ◽  
One Dimensional ◽  
Whole Cells ◽  
O Antigen ◽  
Acetyl Group ◽  
Semi Empirical ◽  
C Nmr

High resolution 1H and 13C nmr spectroscopy at 500 MHz and 125 MHz was used for the structural analysis of the O-antigen of Salmonellalandau, which belongs to the Kauffmann–White serogroup N. This bacterial lipopolysaccharide was extracted from whole cells and hydrolyzed by mild acid to give lipid-free O-polysaccharide. Conventional one-dimensional 1H and 13C nmr data showed the polysaccharide to contain four monosaccharides in each repeating unit and, in addition, to carry an average of one O-acetyl group for every two repeating units. Two-dimensional nmr experiments aided the unambiguous assignment of the 1H and 13C resonances and thereby permitted the structural analysis of this polysaccharide by nmr techniques alone. The structure of the de-O-acetylated repeating unit was established as [Formula: see text][Formula: see text] through the use of methods which included homonuclear shift correlated (COSY and NOESY) experiments. The interpretation of this data was supported and simplified by consideration of firmly established 13C chemical shift assignments obtained from a heteronuclear 1H/13C shift correlated experiment. A three-dimensional model of the O-antigen obtained by semi-empirical calculations is shown to be consistent with interatomic distance constraints imposed by data from 2-D NOESY and one-dimensional nOe difference spectroscopy.

scholarly journals Short term outcomes of three dimensional versus two-dimensional laparoscopic cholecystectomy

2020 ◽  
Vol 37 (1) ◽  
Author(s):  
Abdul Razaque Shaikh ◽  
Aaijaz Ahmed Shaikh ◽  
Mujib Rehman Abbasi
Keyword(s):  
Laparoscopic Cholecystectomy ◽  
Open Cholecystectomy ◽  
Three Dimensional ◽  
Port Site ◽  
Two Dimensional ◽  
Short Term ◽  
Term Outcome ◽  
Conversion To Open Cholecystectomy ◽  
Group A ◽  
Group B

Objective: To compare the short-term outcomes of three dimensional (3D) versus two dimensional (2D) laparoscopic procedures used for cholecystectomy. Methods: This study was conducted at minimally invasive surgery center of Liaquat University of Medical Health and Sciences (LUMHS) Jamshoro Pakistan, between 15th May 2017 to 16th December 2017 after taking informed consent. All patients were diagnosed cases of cholelithiasis without any complications. Patients having risk factors for inability to get access to gall bladder via laparoscope and in whom the chances of conversion to open cholecystectomy were greater were not included as part of study. One group of patients underwent cholecystectomy under 3D laparoscopy while other group underwent 2D laparoscopy. Surgeons included in the study were all well-trained. The short-term outcome noted were intraoperative and postoperative complications, conversion to open, operative time, mortality and hospital stay. Visual strain and headache for the surgeon in three D laparoscopic cholecystectomy. Results: A total of one hundred forty patients were included in the study. Group-A consists of sixty two females and eleven males whereas Group-B comprised of fifty eight females and fifteen males. Eight percent of patients in Group-A whereas in Group-B two percent had gallbladder rupture. Fifteen percent of patients in Group-A whereas 5.4% from Group-B had bleeding from liver bed. One patient from Group-A had CBD (Common Bile Duct) injury. Post-operatively two (2.73%) patients from Group-A had port site bleeding. Six (8.21%) patients had port site infection in Group-A. Conclusion: Three dimensional was found to have low incidence of intra-operative and post-operative complications compared to 2D laparoscopic cholecystectomy. doi: https://doi.org/10.12669/pjms.37.1.3721 How to cite this:Shaikh AR, Shaikh AA, Abbasi M. Short term outcomes of three dimensional versus two-dimensional laparoscopic cholecystectomy. Pak J Med Sci. 2021;37(1):162-166. doi: https://doi.org/10.12669/pjms.37.1.3721 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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