scholarly journals Depth Attenuation Degree Based Visualization for Cardiac Ischemic Electrophysiological Feature Exploration

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Fei Yang ◽  
Lei Zhang ◽  
Weigang Lu ◽  
Lei Liu ◽  
Yue Zhang ◽  
...  

Although heart researches and acquirement of clinical and experimental data are progressively open to public use, cardiac biophysical functions are still not well understood. Due to the complex and fine structures of the heart, cardiac electrophysiological features of interest may be occluded when there is a necessity to demonstrate cardiac electrophysiological behaviors. To investigate cardiac abnormal electrophysiological features under the pathological condition, in this paper, we implement a human cardiac ischemic model and acquire the electrophysiological data of excitation propagation. A visualization framework is then proposed which integrates a novel depth weighted optic attenuation model into the pathological electrophysiological model. The hidden feature of interest in pathological tissue can be revealed from sophisticated overlapping biophysical information. Experiment results verify the effectiveness of the proposed method for intuitively exploring and inspecting cardiac electrophysiological activities, which is fundamental in analyzing and explaining biophysical mechanisms of cardiac functions for doctors and medical staff.


1935 ◽  
Vol 62 (4) ◽  
pp. 599-620 ◽  
Author(s):  
W. B. Hawkins ◽  
G. H. Whipple

A clearer understanding of the various abnormalities which may develop in relation to the experimental or clinical bile fistula will be of value to the laboratory worker as well as to the physician and surgeon. A better comprehension of these diseased conditions will make for a saner analysis of the great mass of experimental data relating to the various types of bile fistula. Too frequently in the literature the bile fistula material is used to debate a physiological state whereas in reality the animal is in a pathological condition. It is possible but not easy to keep a bile fistula dog in a normal state for months or years if proper attention is given to the diet and physical state. The most significant abnormalities are—intestinal disturbances, spontaneous bleeding, osteoporosis, cholelithiasis and duodenal ulcer. Three types of bile fistula were used in our experiments and each one has its advantages and disadvantages. Intestinal intoxication is best controlled by diet, by whole bile or bile salts or combinations of dog and ox bile. Spontaneous bleeding seems to be due to the loss of something by way of the bile and this can be prevented by bile feeding. The blood deficiency appears to be a lack of prothrombin. Osteoporosis appears inevitably after many months if bile is excluded from the intestine. This state is related to the lack of absorption of vitamin D. It is of some interest that liver feeding will prevent it. Duodenal ulcers and cholelithiasis are common in bile fistula dogs and absolute control or prevention is not easy. It may be restated that bile secretion into the intestine is necessary for normal health and even for actual continuation of life beyond a few months' period. Some of these experimental data should be of value to physicians and surgeons in the care and study of human fistula cases and should emphasize the necessity of prompt dietary control.



Author(s):  
Sára Sáray ◽  
Christian A. Rössert ◽  
Shailesh Appukuttan ◽  
Rosanna Migliore ◽  
Paola Vitale ◽  
...  

AbstractAnatomically and biophysically detailed data-driven neuronal models have become widely used tools for understanding and predicting the behavior and function of neurons. Due to the increasing availability of experimental data from anatomical and electrophysiological measurements as well as the growing number of computational and software tools that enable accurate neuronal modeling, there are now a large number of different models of many cell types available in the literature. These models were usually built to capture a few important or interesting properties of the given neuron type, and it is often unknown how they would behave outside their original context. In addition, there is currently no simple way of quantitatively comparing different models regarding how closely they match specific experimental observations. This limits the evaluation, re-use and further development of the existing models. Further, the development of new models could also be significantly facilitated by the ability to rapidly test the behavior of model candidates against the relevant collection of experimental data. We address these problems for the representative case of the CA1 pyramidal cell of the rat hippocampus by developing an open-source Python test suite, which makes it possible to automatically and systematically test multiple properties of models by making quantitative comparisons between the models and electrophysiological data. The tests cover various aspects of somatic behavior, and signal propagation and integration in apical dendrites. To demonstrate the utility of our approach, we applied our tests to compare the behavior of several different hippocampal CA1 pyramidal cell models from the ModelDB database against electrophysiological data available in the literature, and concluded that each of these models provides a good match to experimental results in some domains but not in others. We also show how we employed the test suite to aid the development of models within the European Human Brain Project (HBP), and describe the integration of the tests into the validation framework developed in the HBP, with the aim of facilitating more reproducible and transparent model building in the neuroscience community.Author summaryAnatomically and biophysically detailed neuronal models are useful tools in neuroscience because they allow the prediction of the behavior and the function of the studied cell type under circumstances that are hard to investigate experimentally. However, most detailed biophysical models have been built to capture a few selected properties of the real neuron, and it is often unknown how they would behave under different circumstances, or whether they can be used to successfully answer different scientific questions. To help the modeling community develop better neural models, and make the process of model building more reproducible and transparent, we developed a test suite that enables the comparison of the behavior of models of neurons in the rat hippocampus and their evaluation against experimental data. Applying our tests to several models available in the literature, we show that each model is able to capture some of the important properties of the real neuron but fails to match experimental data in other domains. We also use the test suite in the model development workflow of the European Human Brain Project to aid the construction of better models of hippocampal neurons and networks.



2010 ◽  
Vol 19 (05n06) ◽  
pp. 813-824
Author(s):  
YOSHIHIRO ARITOMO

We analyzed experimental data obtained for the mass distribution of fission fragments in the reactions 36 S +238 U and 30 Si +238 U at several incident energies, which were performed by the JAEA group. Using the dynamical model with the Langevin equation, we precisely investigate the incident energy dependence of the mass distribution of fission fragments. We also consider the fine structures in the mass distribution of fission fragments caused by the nuclear structure at a low incident energy. It is explained why the mass distribution of fission fragments has different features in the two reactions. The fusion cross sections are also estimated.



2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Wei Chen ◽  
Yongxin Yang ◽  
Biao Li

The existing attenuation models for the durability of FRP (fiber-reinforced polymer) composites in hydrothermal environments were compared, and a new coupled strength attenuation model with a temperature parameter was proposed in this paper. A series of durability experiments on GFRP sheets in hydrothermal environments were conducted to validate the accuracy and rationality of the new model. A comparison between experimental data and the calculation results of the coupled model indicated that the new model can fit better with the experimental data and effectively reflect the convergence phenomenon in the strength attenuation of GFRP in hydrothermal environments. With a temperature parameter included, the new model can better predict the service life of GFRP composites at different aging temperatures. According to the coupled attenuation model proposed in this paper, a concept and calculation method of the slow-aging time point are put forward, which can be convenient for the evaluation and design of GFRP structures with long-term durability.



2021 ◽  
Vol 17 (1) ◽  
pp. e1008114
Author(s):  
Sára Sáray ◽  
Christian A. Rössert ◽  
Shailesh Appukuttan ◽  
Rosanna Migliore ◽  
Paola Vitale ◽  
...  

Anatomically and biophysically detailed data-driven neuronal models have become widely used tools for understanding and predicting the behavior and function of neurons. Due to the increasing availability of experimental data from anatomical and electrophysiological measurements as well as the growing number of computational and software tools that enable accurate neuronal modeling, there are now a large number of different models of many cell types available in the literature. These models were usually built to capture a few important or interesting properties of the given neuron type, and it is often unknown how they would behave outside their original context. In addition, there is currently no simple way of quantitatively comparing different models regarding how closely they match specific experimental observations. This limits the evaluation, re-use and further development of the existing models. Further, the development of new models could also be significantly facilitated by the ability to rapidly test the behavior of model candidates against the relevant collection of experimental data. We address these problems for the representative case of the CA1 pyramidal cell of the rat hippocampus by developing an open-source Python test suite, which makes it possible to automatically and systematically test multiple properties of models by making quantitative comparisons between the models and electrophysiological data. The tests cover various aspects of somatic behavior, and signal propagation and integration in apical dendrites. To demonstrate the utility of our approach, we applied our tests to compare the behavior of several different rat hippocampal CA1 pyramidal cell models from the ModelDB database against electrophysiological data available in the literature, and evaluated how well these models match experimental observations in different domains. We also show how we employed the test suite to aid the development of models within the European Human Brain Project (HBP), and describe the integration of the tests into the validation framework developed in the HBP, with the aim of facilitating more reproducible and transparent model building in the neuroscience community.



2002 ◽  
Vol 13 (03) ◽  
pp. 397-403 ◽  
Author(s):  
LIHONG HAN ◽  
BINGCONG GOU ◽  
HAIYUN HU ◽  
FEI WANG

The fine structure energies and fine structure splittings of some low-lying excited states of the beryllium isoelectronic sequence (Z = 4–20) are calculated with multi-configuration-interaction method and restricted variation method. The relativistic corrections and mass polarization are included. The results are in good agreement with other theoretical and experimental data.



Author(s):  
E.C. Chew ◽  
C.L. Li ◽  
D.P. Huang ◽  
H.C. Ho ◽  
L.S. Mak ◽  
...  

An epithelial cell line, NPC/HK1, has recently been established from a biopsy specimen of a recurrent tumour of the nasopharynx which was histologically diagnosed as a moderately to well differentiated squamous cell carcinoma. A definite decrease in the amount of tonofilaments and desmosomes in the NPC/HK1 cells during the cell line establishment was observed. The present communication reports on the fine structures of the NPC/HK1 cells heterotraneplanted in athymic nude mice.



Author(s):  
A. Gómez ◽  
P. Schabes-Retchkiman ◽  
M. José-Yacamán ◽  
T. Ocaña

The splitting effect that is observed in microdiffraction pat-terns of small metallic particles in the size range 50-500 Å can be understood using the dynamical theory of electron diffraction for the case of a crystal containing a finite wedge. For the experimental data we refer to part I of this work in these proceedings.



Author(s):  
Xudong Weng ◽  
Peter Rez

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.



Author(s):  
Hiroki Kurata ◽  
Kazuhiro Nagai ◽  
Seiji Isoda ◽  
Takashi Kobayashi

Electron energy loss spectra of transition metal oxides, which show various fine structures in inner shell edges, have been extensively studied. These structures and their positions are related to the oxidation state of metal ions. In this sence an influence of anions coordinated with the metal ions is very interesting. In the present work, we have investigated the energy loss near-edge structures (ELNES) of some iron compounds, i.e. oxides, chlorides, fluorides and potassium cyanides. In these compounds, Fe ions (Fe2+ or Fe3+) are octahedrally surrounded by six ligand anions and this means that the local symmetry around each iron is almost isotropic.EELS spectra were obtained using a JEM-2000FX with a Gatan Model-666 PEELS. The energy resolution was about leV which was mainly due to the energy spread of LaB6 -filament. The threshole energies of each edges were measured using a voltage scan module which was calibrated by setting the Ni L3 peak in NiO to an energy value of 853 eV.



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