scholarly journals Spatiotemporal Analysis of Multichannel EEG: CARTOOL

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Denis Brunet ◽  
Micah M. Murray ◽  
Christoph M. Michel
Keyword(s):  
Electric Fields ◽  
Spatiotemporal Analysis ◽  
Temporal Segmentation ◽  
Source Imaging ◽  
Experimental Conditions ◽  
Topographic Analysis ◽  
3 Dimensional ◽  
Inverse Solutions ◽  
Electroencephalogram Eeg ◽  
Multichannel Eeg

This paper describes methods to analyze the brain's electric fields recorded with multichannel Electroencephalogram (EEG) and demonstrates their implementation in the software CARTOOL. It focuses on the analysis of the spatial properties of these fields and on quantitative assessment of changes of field topographies across time, experimental conditions, or populations. Topographic analyses are advantageous because they are reference independents and thus render statistically unambiguous results. Neurophysiologically, differences in topography directly indicate changes in the configuration of the active neuronal sources in the brain. We describe global measures of field strength and field similarities, temporal segmentation based on topographic variations, topographic analysis in the frequency domain, topographic statistical analysis, and source imaging based on distributed inverse solutions. All analysis methods are implemented in a freely available academic software package called CARTOOL. Besides providing these analysis tools, CARTOOL is particularly designed to visualize the data and the analysis results using 3-dimensional display routines that allow rapid manipulation and animation of 3D images. CARTOOL therefore is a helpful tool for researchers as well as for clinicians to interpret multichannel EEG and evoked potentials in a global, comprehensive, and unambiguous way.

scholarly journals Comparison of Bite Force in Patients After Treatment of Mandibular Fractures With 3-Dimensional Locking Miniplate and Standard Miniplates

2019 ◽  
Vol 1 (1) ◽  
pp. 7-10
Author(s):  
Gaurav Singh ◽  
Madan Mishra ◽  
Amit Gaur ◽  
Dhritiman Pathak
Keyword(s):  
Treatment Strategies ◽  
Bite Force ◽  
Mandibular Fractures ◽  
Time Intervals ◽  
Experimental Conditions ◽  
3 Dimensional ◽  
The Mean ◽  
Group 2 ◽  
Drilling Conditions ◽  
Group 1

Background: Fractures of the mandible can be studied and described in anatomic terms, functional considerations, treatment strategies, and outcome measures. The performance of any fixation system depends on multiple factors including plate adaptation, screw placement, bone quality, drilling conditions, and postoperative patient compliance. Bite force assesses masticatory muscle function under clinical and experimental conditions. Method: 30 patients with isolated, noncomminuted mandibular fractures were randomly divided into two equal groups. Group 1 patients were treated using 3-dimensional locking miniplates and group 2 patients were treated with standard miniplates. The bite forces were recorded at definite time intervals: preoperatively, and second week, sixth week, third month, and sixth month postoperatively. Result: At 6 weeks postoperative, 3 month postoperative, and 6 month postoperative, the mean bite force was found to be significantly higher among group 1 patients as compared to those in group 2 in all the sites. While at 2 week postoperative, the mean bite force was found to be significantly higher in Group 2 as compared to Group 1 at incisor region. Conclusion: The overall results of the present study show better performance in bite force for the 3-dimensional locking miniplate when compared with standard miniplates.

scholarly journals ConvDip: A convolutional neural network for better M/EEG Source Imaging

2020 ◽  
Author(s):  
Lukas Hecker ◽  
Rebekka Rupprecht ◽  
Ludger Tebartz van Elst ◽  
Juergen Kornmeier
Keyword(s):  
Neural Network ◽  
Inverse Problem ◽  
Convolutional Neural Network ◽  
Brain Activity ◽  
Clinical Diagnostics ◽  
Dipole Model ◽  
Source Imaging ◽  
Eeg Source Imaging ◽  
Eeg Data ◽  
Inverse Solutions

AbstractEEG and MEG are well-established non-invasive methods in neuroscientific research and clinical diagnostics. Both methods provide a high temporal but low spatial resolution of brain activity. In order to gain insight about the spatial dynamics of the M/EEG one has to solve the inverse problem, which means that more than one configuration of neural sources can evoke one and the same distribution of EEG activity on the scalp. Artificial neural networks have been previously used successfully to find either one or two dipoles sources. These approaches, however, have never solved the inverse problem in a distributed dipole model with more than two dipole sources. We present ConvDip, a novel convolutional neural network (CNN) architecture that solves the EEG inverse problem in a distributed dipole model based on simulated EEG data. We show that (1) ConvDip learned to produce inverse solutions from a single time point of EEG data and (2) outperforms state-of-the-art methods (eLORETA and LCMV beamforming) on all focused performance measures. (3) It is more flexible when dealing with varying number of sources, produces less ghost sources and misses less real sources than the comparison methods. (4) It produces plausible inverse solutions for real-world EEG recordings and needs less than 40 ms for a single forward pass. Our results qualify ConvDip as an efficient and easy-to-apply novel method for source localization in EEG and MEG data, with high relevance for clinical applications, e.g. in epileptology and real time applications.

scholarly journals Research on Key Technology of Electrochemical Sterilization and Physical Application for Circulating Cooling Water

2021 ◽  
Vol 2083 (2) ◽  
pp. 022068
Author(s):  
Xiaohui Wang ◽  
Chunyan Song ◽  
Xueying Xie ◽  
Nan Zhang ◽  
Ruiqing Guo ◽  
...  
Keyword(s):  
Electric Fields ◽  
Electrode Materials ◽  
High Efficiency ◽  
Thermal Power ◽  
Cooling Water ◽  
Environmentally Friendly ◽  
Research Progress ◽  
Electrode Spacing ◽  
Experimental Conditions ◽  
Circulating Cooling Water

Abstract As a high-efficiency, low-cost, convenient and environmentally friendly sterilization technology, electrochemical disinfection has developed rapidly in recent years. Electrochemical sterilization is an environmentally friendly sterilization technology. The research progress of this technology in the recent 30 years in sterilization mechanism and electrode materials is summarized. The mechanism of electrochemical sterilization includes the chemical effects of active chlorine, active intermediates, copper or silver ions, and the physical effects of electric fields; the electrode materials used are titanium anode, carbon cathode, and anode. The article combined with electrochemical equipment in a thermal power plant cold open circulating cooling water treatment experiment. Experimental research found that under the conditions of current density of 120A/m2, residence time of 10s, and electrode spacing of 1.8cm, the bactericidal effect can reach 97%. Under certain experimental conditions and a certain period of time, the total number of heterogeneous bacteria in the circulating cooling water after treatment can be effectively inhibited.

3-Dimensional Force Curve and Dissipation Model Acquisition Using the Spectral Inversion Method in Tapping Mode AFM

2011 ◽  
Author(s):  
Jeffrey C. Williams ◽  
Santiago D. Solares
Keyword(s):  
Excitation Amplitude ◽  
Analytical Models ◽  
Inversion Method ◽  
Total Force ◽  
Experimental Conditions ◽  
3 Dimensional ◽  
Select Group ◽  
Feasible Range ◽  
Dissipation Model ◽  
Constant Quality

Atomic force microscopy (AFM) has been a field driving at exploring nanoscale surfaces and measuring both topography as well as material properties. One of the phenomena that has attracted significant interest is tip-sample dissipation, which was initially investigated by Cleveland and coworkers [Appl. Phys. Lett. 72, 2613–2615 (1998)]. In this paper we expand on that work by developing a method to map the total conservative and non-conservative forces simultaneously in space and as a function of relative tip-sample velocity. This is accomplished through Fourier analysis performed on the response of a torsional harmonic cantilever (THC) probe, previously developed by Sahin and coworkers [Nature Nanotechnology 2, 507–514 (2007)]. The effect of a select group of AFM parameters (cantilever resonant frequency, force constant, quality factor, amplitude set point and excitation amplitude) is simulated in a feasible range of experimental conditions, which maximizes the spatial and velocity range of the oscillating tip, such that useful maps of the total force as a function of tip velocity and position can be acquired. We analyze the observed trends and propose an approach to acquire analytical models of the local tip-sample dissipative and conservative forces.

scholarly journals Spastic diparetic does not directly affect the capacity to ascend and descend access ramps: three-dimensional analysis

2017 ◽  
Vol 30 (3) ◽  
pp. 537-547 ◽  
Author(s):  
Tainá Ribas Mélo ◽  
Ana Tereza Bittencourt Guimarães ◽  
Vera Lúcia Israel
Keyword(s):  
Imaging System ◽  
Three Dimensional ◽  
Control Group ◽  
Initial Contact ◽  
Experimental Conditions ◽  
3 Dimensional ◽  
Flexion Extension ◽  
Posterior Trunk ◽  
Hip Flexion ◽  
Study Participants

Abstract Introduction: Diplegic children have difficulties in gait and therefore ramps are used as strategies of accessibility. Objective: The present study investigated the influence of an inclined surface (ascending and descending) on the kinematic characteristics during gait of the diplegic group (DG) when compared to typically developing children of the control group (CG). Methods: Study participants included 20 children (10 with DG and 10 CG) matched by age, which were evaluated in three experimental conditions (horizontal and inclined ascending and inclined descending surfaces of 7º) through an optoelectronic imaging system. Results: Among the linear kinematic variables, only step width differed among groups, however, without influence of the surface. The foot height differed among the groups only in the descending phase, where DG had greater difficulty in raising the foot. The 3-dimensional gait analyses could not provide more evidences of differences in kinematics variables, especially in transverse plane, between DG and CG, but provide some evidence to support that hip range of motion (ROM) during the gait cycle, hip flexion-extension in initial contact, knee ROM and the 2nd anterior-posterior trunk peak amplitude of the DG were influenced on descent by their flexor pattern. Conclusion: The DG was most affected by the inclination plane than CG especially on descent. Although a hip and knee flexor pattern is evident for DG on inclination of 7º, this angle is accessible since it allows independent gait functional activity.

Numerical Simulation of Dielectrophoresis Induced Electrothermal Fluid Flow

2011 ◽  
Vol 483 ◽  
pp. 270-275
Author(s):  
De Li Liu ◽  
Li Guo Chen ◽  
Li Ning Sun
Keyword(s):  
Fluid Flow ◽  
Electric Fields ◽  
Thermal Denaturation ◽  
Heating Effect ◽  
Experimental Conditions ◽  
Biological Particles ◽  
Fluid Field ◽  
Theoretical Investigations ◽  
The Impact ◽  
Electrothermal Flow

Dielectrophoresis (DEP) based microdevices offer a great number of significant advantages for the manipulation of biological particles such as cells, bacteria, viruses and DNA over traditional methods. To enable successfully dielectrophoretic manipulation of biological particles, electric fields of higher intensity need to be generated in order to increase the DEP forces. However, the introduced electric field may cause the joule heating effect and thermal denaturation of biological particles. This paper presents a numerical solution of the DEP force and the resulting electrical electrothermal driven fluid flow on a DEP microdevice. Theoretical investigations were made about the impact of electrothermal flow on DEP based microdevice. The fluid field was solved by coupling electrical, thermal, and mechanical equations. It is shown that under some typical experimental conditions of DEP based manipulation of biological particles, it is necessary to consider the possible influence of the electrothermal flow.

Electro-Hydrodynamic Control of Premixed Turbulent Methane Flames at Pressures Above 1 ATM

2005 ◽  
Author(s):  
T. Hammer ◽  
G. Lins ◽  
D. W. Branston ◽  
F. Dinkelacker ◽  
A. Sakhrieh ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Gas Flow ◽  
Thermal Power ◽  
Combustion Process ◽  
Optical Emission ◽  
Experimental Conditions ◽  
Reaction Zones ◽  
Co Reduction ◽  
Flame Behavior

Electric field control of combustion offers the potential of stabilizing flames and reducing emissions with comparatively little effort. Previous investigations of the effects of electric fields on flames were restricted to atmospheric pressure and the question whether field effects persist at higher pressures remained open. In the present work effects of electric fields on flame behavior are established for pressures up to 10 bar without any indication that this should be an upper limit. Voltage-current measurements and optical emission spectroscopy gave clear evidence that at all experimental conditions under investigation electric field induced ionization and dissociation reactions were negligible with regard to the combustion process. Thus it is concluded that all observed effects are due to electro-hydrodynamic distortions of the gas flow caused by electrostatic forces acting on the ions generated in the reaction zones of the flames. The concentration of pollutants such as CO, NO and NO2 in the presence of an electric field depends on the ratio U/p of electrode voltage U and pressure p which implies that the electric field strength required to obtain a given effect increases linearly with pressure. In an electric field directed towards the burner CO emissions could be reduced by about 90%, irrespective of pressure. The decrease of CO was accompanied by an increase of NOx by about 20%. The electric power required for a CO reduction of 90% amounted to 0.1% of the thermal power. The improvement of the lean blow-off limit upon application of an electric field observed so far ranges from 1 to 3% and increases with pressure.

Quantitative Analysis of Precipitate Compositions in an Al-Li-Mg-Cu Alloy Using Atom Probe Tomography

2010 ◽  
Vol 654-656 ◽  
pp. 914-917 ◽  
Author(s):  
Xiang Yuan Xiong ◽  
Stavroula Moutsos ◽  
Russell King ◽  
Barry C. Muddle
Keyword(s):  
Quantitative Analysis ◽  
Aluminium Alloy ◽  
Atom Probe Tomography ◽  
Lithium Concentration ◽  
Stoichiometric Composition ◽  
Atom Probe ◽  
Field Evaporation ◽  
Experimental Conditions ◽  
3 Dimensional ◽  
Cu Alloy

The composition of  precipitates in aluminium alloy 8090 has been analysed using a 3 dimensional atom probe with fast data acquisition rates. The effects of experimental conditions for the quantitative atom probe analysis have been examined in detail. The results show that i) lithium is prone to preferential DC field evaporation at temperatures > 25K and with a pulse fraction < 20%; ii) the lithium concentration of  precipitates can vary from precipitate to precipitate, ranging from 19.1 to 25.3 at.%, and iii) the stoichiometric composition of the  phase can be obtained provided that the probing temperature is  25K and pulse fraction is  20%.

scholarly journals Ionic transport through a protein nanopore: a Coarse-Grained Molecular Dynamics Study

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Nathalie Basdevant ◽  
Delphine Dessaux ◽  
Rosa Ramirez
Keyword(s):  
Molecular Dynamics ◽  
Lipid Bilayer ◽  
Electric Fields ◽  
Ionic Transport ◽  
Stationary Regime ◽  
Coarse Grained ◽  
Experimental Conditions ◽  
Current Saturation ◽  
Order Of Magnitude ◽  
Dynamics Simulations

Abstract The MARTINI coarse-grained (CG) force field is used to test the ability of CG models to simulate ionic transport through protein nanopores. The ionic conductivity of CG ions in solution was computed and compared with experimental results. Next, we studied the electrostatic behavior of a solvated CG lipid bilayer in salt solution under an external electric field. We showed this approach correctly describes the experimental conditions under a potential bias. Finally, we performed CG molecular dynamics simulations of the ionic transport through a protein nanopore (α-hemolysin) inserted in a lipid bilayer, under different electric fields, for 2–3 microseconds. The resulting I − V curve is qualitatively consistent with experiments, although the computed current is one order of magnitude smaller. Current saturation was observed for potential biases over ±350 mV. We also discuss the time to reach a stationary regime and the role of the protein flexibility in our CG simulations.

Sign in / Sign up

Export Citation Format

Share Document