scholarly journals Abnormal Expression of Connexin43 in Cardiac Injury Induced by S-Band and X-Band Microwave Exposure in Rats

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yue Yin ◽  
Xinping Xu ◽  
Yabing Gao ◽  
Juan Wang ◽  
Binwei Yao ◽  
...  
Keyword(s):  
Electrical Conduction ◽  
Wave Amplitude ◽  
Biological Effects ◽  
Average Power ◽  
Observation Time ◽  
P Wave ◽  
Cardiac Conduction ◽  
Microwave Exposure ◽  
X Band ◽  
Structure And Ultrastructure

Although the effects of microwave exposure on the heart have gradually become the focus of domestic and foreign scholars, the biological effects caused by different doses and different frequency bands of exposure are still unclear. In this study, we will investigate the damaging effect of S-band and X-band microwave composite exposure on cardiac structure and function, as well as the pathophysiological significance of Cx43 in cardiac conduction dysfunction after exposure. We used S- and X-band radiation sources with the average power density of 5 and 10 mW/cm2 to expose Wistar rats to single or composite exposure. At the 6th hour, on the 7th, 14th, and 28th days after exposure, ECG was used to detect the electrical conduction of the heart, and the myocardial enzyme was measured by the automatic biochemical analyzer. We selected the observation time points and groups with severe damage to observe the changes of myocardial structure and ultrastructure with an optical microscope and TEM; and to detect the expression and distribution of Cx43 by western blotting and immunohistochemistry. After exposure, the heart rate increased, the P wave amplitude decreased, and the R wave amplitude increased; the content of the myocardial enzyme in serum increased; the structure and ultrastructure of cardiac tissue were damaged. The damage was dose-dependent and frequency-dependent. The expression of Cx43 in myocardial tissue decreased, and distribution was abnormal. Taken together, these findings suggested that the mechanism of abnormal electrical conduction in the heart of rats by S- and X-band microwave exposure might be related to the decreased expression and disordered distribution of Cx43 after microwave exposure.

12. Laboratory Investigation of P-Wave Amplitude Anisotropy in Limestone

2001 ◽  
pp. 187-204
Author(s):  
Brad A. Bessinger ◽  
Roberto Suárez-Rivera ◽  
Kurt T. Nihei ◽  
L. Brun Hilbert ◽  
Larry R. Myer ◽  
...  
Keyword(s):  
Laboratory Investigation ◽  
Wave Amplitude ◽  
P Wave ◽  
Amplitude Anisotropy

P wave dispersion, Tpeak–Tend interval, and Tp-e/QT ratio in children with psoriasis

2020 ◽  
Vol 30 (3) ◽  
pp. 318-322
Author(s):  
Mecnun Çetin ◽  
İbrahim H. Yavuz ◽  
Mehmet Gümüştaş ◽  
Göknur Ö. Yavuz
Keyword(s):  
Wave Dispersion ◽  
P Wave ◽  
Cardiac Conduction ◽  
Control Group ◽  
Healthy Children ◽  
P Wave Dispersion ◽  
System Disease ◽  
Increased Risk ◽  
Electrocardiographic Parameters ◽  
Key Indicators

AbstractBackground:Psoriasis is a chronic inflammatory, multi-system disease that often begins in childhood and characterised by inflammatory skin, nails, scalp, and joint manifestations. The inflammation in psoriasis may promote some effect on the cardiac conduction system.Objective:The aim of this study is to investigate myocardial repolarisation anomaly on the conducting system in the paediatric psoriasis using P wave dispersion, Tpeak–Tend interval, and Tp-e/QT ratio.Methods:Forty-two patients diagnosed with psoriasis and 37 age- and sex-matched healthy children were enrolled in the study. Electrocardiographic parameters in psoriasis and control group were recorded from an electrocardiogram for each patient.Results:The results indicated that the parameters including Pdis, QTc dis, Tp-e dis interval, and Tp-e max/QTmax ratios, which are known to be key indicators for the prediction of severe atrial or ventricular arrhythmia and sudden cardiac death and also important parameters used as the indicators for the non-invasive evaluation of the transmural heterogeneity were significantly longer in the study group compared to the control group (p < 0.05).Conclusions:This study includes the evidence linking psoriasis with increased myocardial repolarisation heterogeneity. These findings suggest that this patient population may be at an increased risk for arrhythmias. Our findings may be a basis for further studies.

scholarly journals Simulation of the effect of stress-induced anisotropy on borehole compressional wave propagation

Geophysics ◽  
2014 ◽  
Vol 79 (4) ◽  
pp. D205-D216 ◽  
Author(s):  
Xinding Fang ◽  
Michael C. Fehler ◽  
Arthur Cheng
Keyword(s):  
Wave Propagation ◽  
Stress Concentration ◽  
Elastic Properties ◽  
Wave Velocity ◽  
Wave Amplitude ◽  
P Wave ◽  
Azimuthal Variation ◽  
P Wave Velocity ◽  
Velocity Region

Formation elastic properties near a borehole may be altered from their original state due to the stress concentration around the borehole. This can lead to an incorrect estimation of formation elastic properties measured from sonic logs. Previous work has focused on estimating the elastic properties of the formation surrounding a borehole under anisotropic stress loading. We studied the effect of borehole stress concentration on sonic logging in a moderately consolidated Berea sandstone using a two-step approach. First, we used an iterative approach, which combines a rock-physics model and a finite-element method, to calculate the stress-dependent elastic properties of the rock around a borehole subjected to an anisotropic stress loading. Second, we used the anisotropic elastic model obtained from the first step and a finite-difference method to simulate the acoustic response of the borehole. Although we neglected the effects of rock failure and stress-induced crack opening, our modeling results provided important insights into the characteristics of borehole P-wave propagation when anisotropic in situ stresses are present. Our simulation results were consistent with the published laboratory measurements, which indicate that azimuthal variation of the P-wave velocity around a borehole subjected to uniaxial loading is not a simple cosine function. However, on field scale, the azimuthal variation in P-wave velocity might not be apparent at conventional logging frequencies. We found that the low-velocity region along the wellbore acts as an acoustic focusing zone that substantially enhances the P-wave amplitude, whereas the high-velocity region caused by the stress concentration near the borehole results in a significantly reduced P-wave amplitude. This results in strong azimuthal variation of P-wave amplitude, which may be used to infer the in situ stress state.

scholarly journals ECG Measurements to Emphasize Atrial Potentials Using Modified Limb Lead System

2018 ◽  
Vol 7 (3.12) ◽  
pp. 632
Author(s):  
Manikandan K ◽  
Mohanasundaram K
Keyword(s):  
Electrical Activity ◽  
Wave Amplitude ◽  
P Wave ◽  
Electrode Placement ◽  
Atrial Arrhythmias ◽  
Lead System ◽  
Wave Duration ◽  
Normal Limits ◽  
P Wave Duration ◽  
Female Subjects

With the advancement in the field of Electrocardiology (ECG), the acquisition of electrical activity of the heart plays an important role in the diagnosis of various cardiovascular diseases. In general, this activity of conduction is acquired using Standard 12 Lead ECG system. Recently, a Modified Limb Lead system has been developed to study the atrial electrical activity for the diagnosis of atrial arrhythmias. The present study is to derive the normal limits of female subjects using Modified Limb Lead (MLL) system. This study was evaluated in 59 female subjects 19.52 ± 1 (Mean ± S.D) and is primarily involved to study atrial potentials with the use of precordial and modified limb lead position. In sinus rhythm female subjects, the P wave amplitude was 33.06 ± 21.18 µV and the Ta wave amplitude was 20.72 ± 18.16 µV. The P wave duration was 94.22 ± 10.64 ms, the Ta wave duration was 85.51 ± 17.49 ms. The results show that modifications in the limb electrode placement have significant effect on amplitudes and PR segment which may be of great importance for the assessment of atrial potentials.  

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