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Geoffrey L. Ahern - One of the best experts on this subject based on the ideXlab platform.
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Interhemispheric Propagation Time and temporal lobe epileptogenicity
Pathophysiology : the official journal of the International Society for Pathophysiology, 2009Co-Authors: Martin E. Weinand, Benjamin Serxner, David M. Labiner, Geoffrey L. AhernAbstract:Abstract Long-term subdural electroencephalographic (EEG) recording was performed in a series of patients with medically intractable complex partial seizures to test the hypothesis that ictal interhemispheric Propagation Time (IHPT) is correlated with temporal lobe epileptogenicity. In 41 patients, the duration from initial subdural EEG seizure onset to the first appearance of subdural EEG epileptic activity in the contralateral hemisphere (IHPT) was measured in seconds and analyzed for a quantitative relationship to temporal lobe seizure interval (frequency −1 ), in hours. A statistically significant, nonlinear correlation between IHPT and seizure interval was found (Arctan y =−0.009 x 2 +0.598 x +75.187, y =IHPT, in seconds, x =seizure interval, in hours, r =0.326, d.f.=39, t =2.15, p
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Temporal lobe seizure interhemispheric Propagation Time depends on nonepileptic cortical cerebral blood flow.
Epilepsy research, 2001Co-Authors: Martin E. Weinand, David M. Labiner, Geoffrey L. AhernAbstract:In some patients with epilepsy, activation of eloquent cortex using various forms of environmental stimulation and mental activity may induce seizures. The increased neuronal activity resulting from cortical stimulation may be associated with increased regional cerebral blood flow. The vascular steal theory of temporal lobe epilepsy suggests that as nonepileptogenic cortical cerebral blood flow (CBFn) increases, temporal lobe epileptogenicity increases as a result, in part, of decreasing interhemispheric Propagation Time (IHPT). Recently, IHPT has been shown to be a quantitative electrocorticographic measure of temporal lobe epileptogenicity. In the current study, long-term combined subdural-EEG and surface cortical cerebral blood flow (CBF) monitoring was performed to test the hypothesis that IHPT depends upon CBFn. The results show that IHPT is a nonlinear (negative exponential) function of nonepileptic cortical CBF (r=0.507, df=32, t=-2.204, P
Martin E. Weinand - One of the best experts on this subject based on the ideXlab platform.
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Interhemispheric Propagation Time and temporal lobe epileptogenicity
Pathophysiology : the official journal of the International Society for Pathophysiology, 2009Co-Authors: Martin E. Weinand, Benjamin Serxner, David M. Labiner, Geoffrey L. AhernAbstract:Abstract Long-term subdural electroencephalographic (EEG) recording was performed in a series of patients with medically intractable complex partial seizures to test the hypothesis that ictal interhemispheric Propagation Time (IHPT) is correlated with temporal lobe epileptogenicity. In 41 patients, the duration from initial subdural EEG seizure onset to the first appearance of subdural EEG epileptic activity in the contralateral hemisphere (IHPT) was measured in seconds and analyzed for a quantitative relationship to temporal lobe seizure interval (frequency −1 ), in hours. A statistically significant, nonlinear correlation between IHPT and seizure interval was found (Arctan y =−0.009 x 2 +0.598 x +75.187, y =IHPT, in seconds, x =seizure interval, in hours, r =0.326, d.f.=39, t =2.15, p
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Temporal lobe seizure interhemispheric Propagation Time depends on nonepileptic cortical cerebral blood flow.
Epilepsy research, 2001Co-Authors: Martin E. Weinand, David M. Labiner, Geoffrey L. AhernAbstract:In some patients with epilepsy, activation of eloquent cortex using various forms of environmental stimulation and mental activity may induce seizures. The increased neuronal activity resulting from cortical stimulation may be associated with increased regional cerebral blood flow. The vascular steal theory of temporal lobe epilepsy suggests that as nonepileptogenic cortical cerebral blood flow (CBFn) increases, temporal lobe epileptogenicity increases as a result, in part, of decreasing interhemispheric Propagation Time (IHPT). Recently, IHPT has been shown to be a quantitative electrocorticographic measure of temporal lobe epileptogenicity. In the current study, long-term combined subdural-EEG and surface cortical cerebral blood flow (CBF) monitoring was performed to test the hypothesis that IHPT depends upon CBFn. The results show that IHPT is a nonlinear (negative exponential) function of nonepileptic cortical CBF (r=0.507, df=32, t=-2.204, P
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Vascular steal model of human temporal lobe epileptogenicity: the relationship between electrocorticographic interhemispheric Propagation Time and cerebral blood flow
Medical hypotheses, 2000Co-Authors: Martin E. WeinandAbstract:Human temporal lobe epileptogenicity (i.e. seizure frequency) depends on epileptic and non-epileptic cerebral blood flow (CBF). Increasing non-epileptic cortical CBF is associated with reduction in epileptic cortical CBF. Seizure frequency increases logarithmically with non-epileptic cortical CBF increase and epileptic cortical CBF reduction. A model of human temporal lobe epileptogenicity is derived from the mathematical equivalence to the logarithmic function of seizure frequency of (a) epileptic and non-epileptic CBF differential and (b) electrocorticographic (ECoG) interhemispheric Propagation Time (IHPT). The vascular steal model of human temporal lobe epileptogenicity suggests that a small CBF redistribution from non-epileptic to epileptic cortex should produce substantial reduction in temporal lobe seizure frequency in association with prolongation of IHPT. The equivalence of these CBF and ECoG parameters to the logarithmic function of seizure frequency suggests that the interhemispheric temporal lobe perfusion gradient and ECoG Propagation Time may be involved in the fundamental perturbation responsible for human temporal lobe epileptogenicity.
S Cho - One of the best experts on this subject based on the ideXlab platform.
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Electrical and thermal modulation of the Propagation Time in superconducting spiral lines by optoelectronic techniques
IEEE Transactions on Appiled Superconductivity, 2001Co-Authors: S Cho, Cheon LeeAbstract:Current and temperature controlled delays in the Propagation Time of electrical pulses in YBa/sub 2/Cu/sub 3/O/sub 7-x/ (YBCO) spiral transmission lines have been investigated by using optoelectronic techniques. The transmission lines are configured in a stripline geometry, where the central strip consists of a thin film of YBCO embedded in LaAlO/sub 3/. The Propagation Time of electrical pulses through the spiral transmission lines is measured using electrical autocorrelation techniques making use of semiconductor optical switches. The measured Propagation Time shows a quadratic dependence on the applied current, which is in good agreement with the Ginzburg-Landau theory. As the temperature increases, a gradual increase in pulse width and a delay in the Propagation Time of electrical pulses are observed. The results are used to determine the actual temperature-dependent function of the magnetic penetration depth of YBCO spiral lines.
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Optical tuning of Propagation Time in ? superconducting delay lines
Superconductor Science and Technology, 1996Co-Authors: S ChoAbstract:We present the observation of an optical pulse energy controlled delay in the Propagation Time of electrical picosecond pulses in (YBCO) superconducting delay lines. The delay lines were patterned in the geometry of a microstrip and were illuminated by the frequency-doubled output (532 nm) of an Nd:YAG laser. The Propagation Time of picosecond electrical pulses through the delay lines was measured using an electrical autocorrelation technique with photoconductive switches. The experiments were conducted at 30 and 55 K and delay tuning up to 54 ps was observed. The measured Propagation Time shows a quadratic dependence on optical pulse energy (p), , where is a critical optical pulse energy beyond which superconductivity has disappeared.
David M. Labiner - One of the best experts on this subject based on the ideXlab platform.
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Interhemispheric Propagation Time and temporal lobe epileptogenicity
Pathophysiology : the official journal of the International Society for Pathophysiology, 2009Co-Authors: Martin E. Weinand, Benjamin Serxner, David M. Labiner, Geoffrey L. AhernAbstract:Abstract Long-term subdural electroencephalographic (EEG) recording was performed in a series of patients with medically intractable complex partial seizures to test the hypothesis that ictal interhemispheric Propagation Time (IHPT) is correlated with temporal lobe epileptogenicity. In 41 patients, the duration from initial subdural EEG seizure onset to the first appearance of subdural EEG epileptic activity in the contralateral hemisphere (IHPT) was measured in seconds and analyzed for a quantitative relationship to temporal lobe seizure interval (frequency −1 ), in hours. A statistically significant, nonlinear correlation between IHPT and seizure interval was found (Arctan y =−0.009 x 2 +0.598 x +75.187, y =IHPT, in seconds, x =seizure interval, in hours, r =0.326, d.f.=39, t =2.15, p
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Temporal lobe seizure interhemispheric Propagation Time depends on nonepileptic cortical cerebral blood flow.
Epilepsy research, 2001Co-Authors: Martin E. Weinand, David M. Labiner, Geoffrey L. AhernAbstract:In some patients with epilepsy, activation of eloquent cortex using various forms of environmental stimulation and mental activity may induce seizures. The increased neuronal activity resulting from cortical stimulation may be associated with increased regional cerebral blood flow. The vascular steal theory of temporal lobe epilepsy suggests that as nonepileptogenic cortical cerebral blood flow (CBFn) increases, temporal lobe epileptogenicity increases as a result, in part, of decreasing interhemispheric Propagation Time (IHPT). Recently, IHPT has been shown to be a quantitative electrocorticographic measure of temporal lobe epileptogenicity. In the current study, long-term combined subdural-EEG and surface cortical cerebral blood flow (CBF) monitoring was performed to test the hypothesis that IHPT depends upon CBFn. The results show that IHPT is a nonlinear (negative exponential) function of nonepileptic cortical CBF (r=0.507, df=32, t=-2.204, P
Carlson Joshua - One of the best experts on this subject based on the ideXlab platform.
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Throttling positive semidefinite zero forcing Propagation Time on graphs
Iowa State University Digital Repository, 2019Co-Authors: Carlson Joshua, Hogben Leslie, Kritschgau Jürgen, Lorenzen Kate, Ross, Michael S., Selken Seth, Valle Martinez VicenteAbstract:Zero forcing is a process on a graph that colors vertices blue by starting with some of the vertices blue and applying a color change rule. Throttling minimizes the sum of the size of the initial blue vertex set and the number of the Time steps needed to color the graph. We study throttling for positive semidefinite zero forcing. We establish a tight lower bound on the positive semidefinite throttling number as a function of the order, maximum degree, and positive semidefinite zero forcing number of the graph, and determine the positive semidefinite throttling numbers of paths, cycles, and full binary trees. We characterize the graphs that have extreme positive semidefinite throttling numbers
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Throttling positive semidefinite zero forcing Propagation Time on graphs
'Elsevier BV', 2018Co-Authors: Carlson Joshua, Hogben Leslie, Kritschgau Jürgen, Lorenzen Kate, Ross, Michael S., Selken Seth, Martinez, Vicente ValleAbstract:Zero forcing is a process on a graph that colors vertices blue by starting with some of the vertices blue and applying a color change rule. Throttling minimizes the sum of the size of the initial blue vertex set and the number of the Time steps needed to color the graph. We study throttling for positive semidefinite zero forcing. We establish a tight lower bound on the positive semidefinite throttling number as a function of the order, maximum degree, and positive semidefinite zero forcing number of the graph, and determine the positive semidefinite throttling numbers of paths, cycles, and full binary trees. We characterize the graphs that have extreme positive semidefinite throttling numbers.Comment: 20 pages, 7 figures, in press, Discrete Appl. Mat
