Intracellular Recording of Cardiomyocytes by Integrated Electrical Signal Recording and Electrical Pulse Regulating System

The electrophysiological signal can reflect the basic activity of cardiomyocytes, which is often used to study the working mechanism of heart. Intracellular recording is a powerful technique for studying transmembrane potential, proving a favorable strategy for electrophysiological research. To obtain high-quality and high-throughput intracellular electrical signals, an integrated electrical signal recording and electrical pulse regulating system based on nanopatterned microelectrode array (NPMEA) is developed in this work. Due to the large impedance of the electrode, a high-input impedance preamplifier is required. The high-frequency noise of the circuit and the baseline drift of the sensor are suppressed by a band-pass filter. After amplifying the signal, the data acquisition card (DAQ) is used to collect the signal. Meanwhile, the DAQ is utilized to generate pulses, achieving the electroporation of cells by NPMEA. Each channel uses a voltage follower to improve the pulse driving ability and isolates each electrode. The corresponding recording control software based on LabVIEW is developed to control the DAQ to collect, display and record electrical signals, and generate pulses. This integrated system can achieve high-throughput detection of intracellular electrical signals and provide a reliable recording tool for cell electro-physiological investigation.

Transcriptome Analyses of In Vitro Exercise Models by Clenbuterol Supplementation or Electrical Pulse Stimulation

Exercise has beneficial effects on human health and is affected by two different pathways; motoneuron and endocrine. For the advancement of exercise research, in vitro exercise models are essential. We established two in vitro exercise models using C2C12 myotubes; EPS (electrical pulse stimulation) for a motoneuron model and clenbuterol, a specific β2 adrenergic receptor agonist, treatment for an endocrine model. For clenbuterol treatment, we found that Ppargc1a was induced only in low glucose media (1 mg/mL) using a 1-h treatment of 30 ng/mL clenbuterol. Global transcriptional changes of clenbuterol treatment were analyzed by RNA-seq and gene ontology analyses and indicated that mitogenesis and the PI3K-Akt pathway were enhanced, which is consistent with the effects of exercise. Cxcl1 and Cxcl5 were identified as candidate myokines induced by adrenaline. As for the EPS model, we compared 1 Hz of 1-pulse EPS and 1 Hz of 10-pulse EPS for 24 h and determined Myh gene expressions. Ten-pulse EPS induced higher Myh2 and Myh7 expression. Global transcriptional changes of 10-pulse EPS were also analyzed using RNA-seq, and gene ontology analyses indicated that CaMK signaling and hypertrophy pathways were enhanced, which is also consistent with the effects of exercise. In this paper, we provided two transcriptome results of in vitro exercise models and these databases will contribute to advances in exercise research.

Insulator filth monitoring and situation awareness based on ultraviolet pulse and least square method

To monitor the filth state of insulators in time, a method based on ultraviolet pulse method is proposed to monitor the filth status of insulators, which can detect the early corona discharge of insulators by detecting UV signals and determine the degree of insulator filth. On this basis, the response characteristics of spot area to electrical pulse signal are studied and theoretical analysis is carried out, the relationship between spot area and electrical pulse signal amplitude is studied, and the correlation curve is obtained. By observing the change law of image size with the observation distance in ultraviolet image. the experiment found that the image size of UV channel and the image size of visible light channel increased or decreased in approximate proportion with the observation distance and proposed a new method to estimate the “discharge imaging area ” of discharge on the surface of the insulator by using the image information of the visible light channel. According to the discharge “relative spot area mean”, one minute time “number of large spot area image frames” two ultraviolet imaging parameters used to characterize the filth discharge characteristics, combined with the ambient humidity to establish a fuzzy logic reasoning model of the filth state, to achieve the assessment of the filth state of the insulator. By using the proposed UV image processing method, the accuracy of insulator filth detection is improved.

Contractile Activity of Myotubes Derived from Human Induced Pluripotent Stem Cells: A Model of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a genetic disorder that results from deficiency of the dystrophin protein. In recent years, DMD pathological models have been created using induced pluripotent stem (iPS) cells derived from DMD patients. In addition, gene therapy using CRISPR-Cas9 technology to repair the dystrophin gene has been proposed as a new treatment method for DMD. However, it is not known whether the contractile function of myotubes derived from gene-repaired iPS cells can be restored. We therefore investigated the maturation of myotubes in electrical pulse stimulation culture and examined the effect of gene repair by observing the contractile behaviour of myotubes. The contraction activity of myotubes derived from dystrophin-gene repaired iPS cells was improved by electrical pulse stimulation culture. The iPS cell method used in this study for evaluating muscle contractile activity is a useful technique for analysing the mechanism of hereditary muscular disease pathogenesis and for evaluating the efficacy of new drugs and gene therapy.

Higher glucose availability augments the metabolic responses of the C2C12 myotubes to exercise-like electrical pulse stimulation

The application of exercise-like electrical pulse simulation (EL-EPS) has become a widely used exercise mimetic in vitro. EL-EPS produces similar physiological responses as in vivo exercise, while less is known about the detailed metabolic effects. Routinely the C2C12 myotubes are cultured in high glucose medium (4.5 g/l), which may alter EL-EPS responses. In this study, we evaluate the metabolic effects of EL-EPS under the high and low glucose (1.0 g/l) conditions to understand how substrate availability affects the myotube response to EL-EPS.The C2C12 myotube, media and cell-free media metabolites were analyzed using untargeted nuclear magnetic resonance (NMR)-based metabolomics. Further, translational and metabolic changes and possible exerkine effects were analyzed. EL-EPS enhanced substrate utilization as well as production and secretion of lactate, acetate, 3-hydroxybutyrate and branched chain fatty acids (BCFAs). The increase in BCFAs correlated with branched chain amino acids (BCAAs) and BCFAs were strongly decreased when myotubes were cultured without BCAAs suggesting the action of acyl-CoA thioesterases on BCAA catabolites. Notably, not all EL-EPS responses were augmented by high glucose because EL-EPS increased phosphorylated c-Jun N-terminal kinase and interleukin-6 secretion independent of glucose availability. Administration of acetate and EL-EPS conditioned media on HepG2 hepatocytes had no adverse effects on lipolysis or triacylglycerol content.Our results demonstrate that unlike in cell-free media, the C2C12 myotube and media metabolites were affected by EL-EPS, particularly under high glucose condition suggesting that media composition should be considered in future EL-EPS studies. Further, acetate and BCFAs were identified as putative exerkines warranting more research.

Optical switches based semiconductor optical amplifiers (SOAs) for performance characteristics enhancement by using various electrical pulse generators

This work has reported the optical switches based semiconductor optical amplifiers (SOAs) for the performance of the characteristics enhancement by using various electrical pulse generators. Max. Q, bit error rate (BER) after light detector, max. signal power (MSP), min. noise power (MNNP), and total optical power after power combiner based SOAs with various pulse generators are simulated and clarified. Return to zero (RZ) pulse code has clarified max Q than other pulse generators. The max output signal power is improved with Gaussian pulse in compared to other pulse generators. Triangle/RZ pulse generators have presented better total optical power than other proposed generators.