ECAPs are the summary of multiple neurons’ spikes which could be recorded by a bidirectional stimulation-recording system via the cochlear implant,with the artifact elimination paradigms of forward-masking subtractio...ECAPs are the summary of multiple neurons’ spikes which could be recorded by a bidirectional stimulation-recording system via the cochlear implant,with the artifact elimination paradigms of forward-masking subtraction paradigm or alternating polarity paradigm.Three kinds of FDA approved cochlear implants support ECAP testing.This article is to summarize the clinical application of ECAP lest.ECAP test after insertion of electrode during implant operation has been widely used during cochlear implant surgery.In recent years.ECAP thresholds are also used to estimate the T levels and C levels helping programming.However,correlation between ECAP thresholds and psychophysical thresholds is affected by many factors.So far,ECAPs cannot yet be a good indicator of post-operative hearing and speech performance.展开更多
In this paper, the authors investigate compound action potentials formed when the underlying tract's axons have current-mediated coupling amongst themselves, and no field-mediated coupling. The key finding of the ...In this paper, the authors investigate compound action potentials formed when the underlying tract's axons have current-mediated coupling amongst themselves, and no field-mediated coupling. The key finding of the paper is that, for the case of biophysically inhomogeneous axon tracts, the compound action potential is governed by a Hodgkin-Huxley like equation itself in certain cases. The paper extends an earlier result for the identical axon case.展开更多
Electrically evoked compound action potential(e CAP) amplitudes elicited at suprathreshold levels were assessed as a measure of the effectiveness of cochlear implant(CI) stimulation. Twenty-one individuals participate...Electrically evoked compound action potential(e CAP) amplitudes elicited at suprathreshold levels were assessed as a measure of the effectiveness of cochlear implant(CI) stimulation. Twenty-one individuals participated; one was excluded due to facial stimulation during e CAP testing. For each participant, e CAPs were elicited with stimulation from seven electrodes near the upper limit of the individual's electrical dynamic range. A reduced-channel CI program was created using those same seven electrodes, and participants performed a vowel discrimination task. Consistent with previous reports, e CAP amplitudes varied across tested electrodes; the profiles were unique to each individual. In 6subjects(30%), e CAP amplitude variability was partially explained by the impedance of the recording electrode. The remaining amplitude variability within subjects, and the variability observed across subjects could not be explained by recording electrode impedance. This implies that other underlying factors, such as variations in neural status across the array, are responsible. Across-site mean e CAP amplitude was significantly correlated with vowel discrimination scores(r^2= 0.56). A single e CAP amplitude measured from the middle of the array was also significantly correlated with vowel discrimination, but the correlation was weaker(r^2= 0.37), though not statistically different from the acrosssite mean. Normalizing each e CAP amplitude by its associated recording electrode impedance did not improve the correlation with vowel discrimination(r^2= 0.52). Further work is needed to assess whether combining e CAP amplitude with other measures of the electrode-neural interface and/or with more central measures of auditory function provides a more complete picture of auditory function in CI recipients.展开更多
Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional“belly-tendon”montage does not accurately and completely reflect the action potential of the ulnar nerve domi...Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional“belly-tendon”montage does not accurately and completely reflect the action potential of the ulnar nerve dominating the abductor digiti minimi muscle due to the effects of far-field potentials of intrinsic hand muscles.A new method of ulnar nerve compound muscle action potential measurement was developed in 2020,which adjusts the E2 electrode from the distal tendon of the abductor digitorum to the middle of the back of the proximal wrist.This new method may reduce the influence of the reference electrode and better reflect the actual ulnar nerve compound muscle action potential.In this prospective cross-sectional study,we included 64 patients with amyotrophic lateral sclerosis and 64 age-and sex-matched controls who underwent conventional and novel ulnar nerve compound muscle action potential measurement between April 2020 and May 2021 in Peking University Third Hospital.The compound muscle action potential waveforms recorded by the new montage were unimodal and more uniform than those recorded by traditional montage.In the controls,no significant difference in the compound muscle action potential waveforms was found between the traditional montage and new montage recordings.In amyotrophic lateral sclerosis patients presenting with abductor digiti minimi spontaneous activity and muscular atrophy,the amplitude of compound muscle action potential-pE2 was significantly lower than that of compound muscle action potential-dE2(P<0.01).Using the new method,damaged axons were more likely to exhibit more severe amplitude decreases than those measured with the traditional method,in particular for patients in early stage amyotrophic lateral sclerosis.In addition,the decline in compound muscle action potential amplitude measured by the new method was correlated with a decrease in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale scores.These findings suggest that the new ulnar nerve compound muscle action potential measurement montage reduces the effects of the reference electrode through altering the E2 electrode position,and that this method is more suitable for monitoring disease progression than the traditional montage.This method may be useful as a biomarker for longitudinal follow-up and clinical trials in amyotrophic lateral sclerosis.展开更多
The distance between the two electrode tips can greatly influence the parameters used for record- ing compound nerve action potentials. To investigate the optimal parameters for these recordings in the rat median nerv...The distance between the two electrode tips can greatly influence the parameters used for record- ing compound nerve action potentials. To investigate the optimal parameters for these recordings in the rat median nerve, we dissociated the nerve using different methods and compound nerve action potentials were orthodromically or antidromically recorded with different electrode spac- ings. Compound nerve action potentials could be consistently recorded using a method in which the middle part of the median nerve was intact, with both ends dissociated from the surrounding fascia and a ground wire inserted into the muscle close to the intact part. When the distance be- tween two stimulating electrode tips was increased, the threshold and supramaximal stimulating intensity of compound nerve action potentials were gradually decreased, but the amplitude was not changed significantly. When the distance between two recording electrode tips was increased, the amplitude was gradually increased, but the threshold and supramaximal stimulating intensity exhibited no significant change. Different distances between recording and stimulating sites did not produce significant effects on the aforementioned parameters. A distance of 5 mm between recording and stimulating electrodes and a distance of 10 mm between recording and stimulating sites were found to be optimal for compound nerve action potential recording in the rat median nerve. In addition, the orthodromic compound action potential, with a biphasic waveform that was more stable and displayed less interference （however also required a higher threshold and higher supramaximal stimulus）, was found to be superior to the antidromic compound action potential.展开更多
The inhibitive action of CaSO_4 towards corrosion of aluminium in 1 mol/L HCl has been inveetigated by using fluorometrio and weight loss techniques.The results show that the inhibitor exhibits an outstanding function...The inhibitive action of CaSO_4 towards corrosion of aluminium in 1 mol/L HCl has been inveetigated by using fluorometrio and weight loss techniques.The results show that the inhibitor exhibits an outstanding function of inhibition,especially at higher tempe- ratures,and it was found to be predomiantly of cathodic rate control.Ths mechanism of inhibition and the effect of CdSO_4 on the corrosion kinetics are also discussed.展开更多
This article represents the main positions of the theory of pleiotropic action of biologically active compounds (BACs) and medicines, which has been designed by the author based on her own experimental researches. The...This article represents the main positions of the theory of pleiotropic action of biologically active compounds (BACs) and medicines, which has been designed by the author based on her own experimental researches. The term “pleiotropy” means the ability of the BACs and medicines to implement more than one mechanism of action resulting in the specific biological (pharmacological) effect. The interaction of these mechanisms forms a distinct pattern of biological response (pleiotropic pattern), which reflects the change in his character with the increased dose (concentration)-dependent efficacy of BACs and medicines. The article consists of description of different pleiotropic patterns established in experiments on the model of reactive oxygen species (ROS) generation by macrophages dependent on activity of specialized enzyme called Nox2-NAD(P)H oxidase (Nox2, EC 1.6.3.1). Moreover, it consists of explanation of pharmacodynamic nature of pleiotropic patterns by means of application Chou-Talalay median effect equalization and combination index (CI) theory. The novel theory explains unsolved until now universal aspects of activity BACs and medicines, such as slope angles of “dose-effect” dependences in the conditions relevant in vivo, and it is of fundamental interest. However, it has applications in experimental pharmacology, as it allows defining the choice of the individual compounds and combinations, modulating the trust effect selectively and efficiently. This knowledge opens up new approaches to medicines discovery and evaluation, their rational dosing and combining.展开更多
According to the Cd-Sb alloy phase diagram, resistivity, heat capacity, partial molar entropy and viscosity,the structural units of this alloy melt have been determined as Cd and Sb atoms as well as Cd3Sb2, Cd4Sb3 and...According to the Cd-Sb alloy phase diagram, resistivity, heat capacity, partial molar entropy and viscosity,the structural units of this alloy melt have been determined as Cd and Sb atoms as well as Cd3Sb2, Cd4Sb3 and CdSb compounds.Based on these structural units and the coexistence theory of metallic melt structure involing compound formation,a calculating model of mass action concentrations has been deduced.The calculated mass action concentrations Ncd are in good agreement with measured activities acd. The Gibbs standard free energy of formatioin for above three compunds have been obtained too.展开更多
基金supported by grants from the National Basic Research Program of China(973 Program)(#2012CB967900)Science and Technology Innovation Nursery Foundation of PLA General Hospital(13KMM14)Clinical Research Supporting Foundation of PLA General Hospital(2012FC-TSYS-3056)
文摘ECAPs are the summary of multiple neurons’ spikes which could be recorded by a bidirectional stimulation-recording system via the cochlear implant,with the artifact elimination paradigms of forward-masking subtraction paradigm or alternating polarity paradigm.Three kinds of FDA approved cochlear implants support ECAP testing.This article is to summarize the clinical application of ECAP lest.ECAP test after insertion of electrode during implant operation has been widely used during cochlear implant surgery.In recent years.ECAP thresholds are also used to estimate the T levels and C levels helping programming.However,correlation between ECAP thresholds and psychophysical thresholds is affected by many factors.So far,ECAPs cannot yet be a good indicator of post-operative hearing and speech performance.
文摘In this paper, the authors investigate compound action potentials formed when the underlying tract's axons have current-mediated coupling amongst themselves, and no field-mediated coupling. The key finding of the paper is that, for the case of biophysically inhomogeneous axon tracts, the compound action potential is governed by a Hodgkin-Huxley like equation itself in certain cases. The paper extends an earlier result for the identical axon case.
基金supported by the National Institutes of Health, National Institute on Deafness and Other Communication Disorders under the following grants awarded to the University of Iowa: F31DC013202, P50DC000242, and R01DC012082funded in part by the University of Iowa Department of Communication Sciences and Disorders
文摘Electrically evoked compound action potential(e CAP) amplitudes elicited at suprathreshold levels were assessed as a measure of the effectiveness of cochlear implant(CI) stimulation. Twenty-one individuals participated; one was excluded due to facial stimulation during e CAP testing. For each participant, e CAPs were elicited with stimulation from seven electrodes near the upper limit of the individual's electrical dynamic range. A reduced-channel CI program was created using those same seven electrodes, and participants performed a vowel discrimination task. Consistent with previous reports, e CAP amplitudes varied across tested electrodes; the profiles were unique to each individual. In 6subjects(30%), e CAP amplitude variability was partially explained by the impedance of the recording electrode. The remaining amplitude variability within subjects, and the variability observed across subjects could not be explained by recording electrode impedance. This implies that other underlying factors, such as variations in neural status across the array, are responsible. Across-site mean e CAP amplitude was significantly correlated with vowel discrimination scores(r^2= 0.56). A single e CAP amplitude measured from the middle of the array was also significantly correlated with vowel discrimination, but the correlation was weaker(r^2= 0.37), though not statistically different from the acrosssite mean. Normalizing each e CAP amplitude by its associated recording electrode impedance did not improve the correlation with vowel discrimination(r^2= 0.52). Further work is needed to assess whether combining e CAP amplitude with other measures of the electrode-neural interface and/or with more central measures of auditory function provides a more complete picture of auditory function in CI recipients.
基金supported by the National Natural Science Foundation of China,Nos.81873784,82071426Clinical Cohort Construction Program of Peking University Third Hospital,No.BYSYDL2019002(all to DSF)。
文摘Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional“belly-tendon”montage does not accurately and completely reflect the action potential of the ulnar nerve dominating the abductor digiti minimi muscle due to the effects of far-field potentials of intrinsic hand muscles.A new method of ulnar nerve compound muscle action potential measurement was developed in 2020,which adjusts the E2 electrode from the distal tendon of the abductor digitorum to the middle of the back of the proximal wrist.This new method may reduce the influence of the reference electrode and better reflect the actual ulnar nerve compound muscle action potential.In this prospective cross-sectional study,we included 64 patients with amyotrophic lateral sclerosis and 64 age-and sex-matched controls who underwent conventional and novel ulnar nerve compound muscle action potential measurement between April 2020 and May 2021 in Peking University Third Hospital.The compound muscle action potential waveforms recorded by the new montage were unimodal and more uniform than those recorded by traditional montage.In the controls,no significant difference in the compound muscle action potential waveforms was found between the traditional montage and new montage recordings.In amyotrophic lateral sclerosis patients presenting with abductor digiti minimi spontaneous activity and muscular atrophy,the amplitude of compound muscle action potential-pE2 was significantly lower than that of compound muscle action potential-dE2(P<0.01).Using the new method,damaged axons were more likely to exhibit more severe amplitude decreases than those measured with the traditional method,in particular for patients in early stage amyotrophic lateral sclerosis.In addition,the decline in compound muscle action potential amplitude measured by the new method was correlated with a decrease in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale scores.These findings suggest that the new ulnar nerve compound muscle action potential measurement montage reduces the effects of the reference electrode through altering the E2 electrode position,and that this method is more suitable for monitoring disease progression than the traditional montage.This method may be useful as a biomarker for longitudinal follow-up and clinical trials in amyotrophic lateral sclerosis.
基金supported by grants from Hand Function Research Center in Fudan University,Chinathe Project 211 in China,No.211XKZ
文摘The distance between the two electrode tips can greatly influence the parameters used for record- ing compound nerve action potentials. To investigate the optimal parameters for these recordings in the rat median nerve, we dissociated the nerve using different methods and compound nerve action potentials were orthodromically or antidromically recorded with different electrode spac- ings. Compound nerve action potentials could be consistently recorded using a method in which the middle part of the median nerve was intact, with both ends dissociated from the surrounding fascia and a ground wire inserted into the muscle close to the intact part. When the distance be- tween two stimulating electrode tips was increased, the threshold and supramaximal stimulating intensity of compound nerve action potentials were gradually decreased, but the amplitude was not changed significantly. When the distance between two recording electrode tips was increased, the amplitude was gradually increased, but the threshold and supramaximal stimulating intensity exhibited no significant change. Different distances between recording and stimulating sites did not produce significant effects on the aforementioned parameters. A distance of 5 mm between recording and stimulating electrodes and a distance of 10 mm between recording and stimulating sites were found to be optimal for compound nerve action potential recording in the rat median nerve. In addition, the orthodromic compound action potential, with a biphasic waveform that was more stable and displayed less interference （however also required a higher threshold and higher supramaximal stimulus）, was found to be superior to the antidromic compound action potential.
文摘The inhibitive action of CaSO_4 towards corrosion of aluminium in 1 mol/L HCl has been inveetigated by using fluorometrio and weight loss techniques.The results show that the inhibitor exhibits an outstanding function of inhibition,especially at higher tempe- ratures,and it was found to be predomiantly of cathodic rate control.Ths mechanism of inhibition and the effect of CdSO_4 on the corrosion kinetics are also discussed.
文摘This article represents the main positions of the theory of pleiotropic action of biologically active compounds (BACs) and medicines, which has been designed by the author based on her own experimental researches. The term “pleiotropy” means the ability of the BACs and medicines to implement more than one mechanism of action resulting in the specific biological (pharmacological) effect. The interaction of these mechanisms forms a distinct pattern of biological response (pleiotropic pattern), which reflects the change in his character with the increased dose (concentration)-dependent efficacy of BACs and medicines. The article consists of description of different pleiotropic patterns established in experiments on the model of reactive oxygen species (ROS) generation by macrophages dependent on activity of specialized enzyme called Nox2-NAD(P)H oxidase (Nox2, EC 1.6.3.1). Moreover, it consists of explanation of pharmacodynamic nature of pleiotropic patterns by means of application Chou-Talalay median effect equalization and combination index (CI) theory. The novel theory explains unsolved until now universal aspects of activity BACs and medicines, such as slope angles of “dose-effect” dependences in the conditions relevant in vivo, and it is of fundamental interest. However, it has applications in experimental pharmacology, as it allows defining the choice of the individual compounds and combinations, modulating the trust effect selectively and efficiently. This knowledge opens up new approaches to medicines discovery and evaluation, their rational dosing and combining.
文摘According to the Cd-Sb alloy phase diagram, resistivity, heat capacity, partial molar entropy and viscosity,the structural units of this alloy melt have been determined as Cd and Sb atoms as well as Cd3Sb2, Cd4Sb3 and CdSb compounds.Based on these structural units and the coexistence theory of metallic melt structure involing compound formation,a calculating model of mass action concentrations has been deduced.The calculated mass action concentrations Ncd are in good agreement with measured activities acd. The Gibbs standard free energy of formatioin for above three compunds have been obtained too.
