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1.
Rev Sci Instrum ; 95(4)2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38557878

ABSTRACT

With the rapid popularization of wireless electronic devices, there has been an increasing concern about the impacts of the electromagnetic environment on health. However, most research reports on the biological effects of microwaves have focused on a single frequency point. In reality, people are exposed to complex electromagnetic environments that consist of multiple frequency microwave signals in their daily lives. It is important to investigate whether multi-frequency combined microwave energies have different biological effects compared with single frequency microwave energy. Unfortunately, there are limited reports on this topic due to the lack of suitable platforms for research on multi-frequency microwave energy combined with biological exposure. To address this issue, this study presents a setup that has a very wide working frequency bandwidth and can be compatible with single frequency and multi-frequency microwave combined exposure. Moreover, it can achieve relatively equal exposure to multiple biological samples at any frequency point in the working frequency range, which is crucial for electromagnetic biology research. The experimental results are in good agreement with the simulation results, confirming its capability to facilitate the study of complex electromagnetic environment effects on organisms.


Subject(s)
Microwaves
2.
Biochem Biophys Res Commun ; 658: 97-106, 2023 05 28.
Article in English | MEDLINE | ID: mdl-37030070

ABSTRACT

BACKGROUND: Evidence shows that microwaves radiation may have various biological effects on central nervous system. Role of electromagnetic fields in neurodegenerative diseases, especially AD, has been widely studied, but results of these studies are inconsistent. Therefore, the above effects were verified again and the mechanism was preliminarily discussed. METHODS: Amyloid precursor protein (APP/PS1) and WT mice were exposed to long-term microwave radiation for 270 days (900 MHz, SAR: 0.25-1.055 W/kg, 2 h/day, alternately), and related indices were assessed at 90, 180 and 270 days. Cognition was evaluated by Morris water maze, Y maze and new object recognition tests. Congo red staining, immunohistochemistry and ELISA were used to analyze Aß plaques, Aß40 and Aß42 content. Differentially expressed proteins in hippocampus between microwave-exposed and unexposed AD mice were identified by proteomics. RESULTS: Spatial and working memory was improved in AD mice after long-term 900 MHz microwave exposure compared with after sham exposure. Microwave radiation (900 MHz) for 180 or 270 days did not induce Aß plaque formation in WT mice but inhibited Aß accumulation in the cerebral cortex and hippocampus in 2- and 5-month-old APP/PS1 mice. This effect mainly occurred in the late stage of the disease and may have been attributed to downregulation of apolipoprotein family member and SNCA expression and excitatory/inhibitory neurotransmitter rebalance in the hippocampus. CONCLUSIONS: The present results indicated that long-term microwave radiation can retard AD development and exert a beneficial effect against AD, suggesting that 900 MHz microwave exposure may be a potential therapy for AD.


Subject(s)
Alzheimer Disease , Mice , Animals , Alzheimer Disease/therapy , Alzheimer Disease/metabolism , Amyloid beta-Peptides/metabolism , Mice, Transgenic , Electromagnetic Fields , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Hippocampus/metabolism , Disease Models, Animal , Presenilin-1/genetics , Presenilin-1/metabolism
3.
Cell Commun Signal ; 21(1): 34, 2023 02 13.
Article in English | MEDLINE | ID: mdl-36782203

ABSTRACT

Health hazards from long-term exposure to microwaves, especially the potential for changes in cognitive function, are attracting increasing attention. The purpose of this study was to explore changes in spatial learning and memory and synaptic structure and to identify differentially expressed proteins in hippocampal and serum exosomes after long-term exposure to 2.856 and 9.375 GHz microwaves. The spatial reference learning and memory abilities and the structure of the DG area were impaired after long-term exposure to 2.856 and 9.375 GHz microwaves. We also found a decrease in SNARE-associated protein Snapin and an increase in charged multivesicular body protein 3 in the hippocampus, indicating that synaptic vesicle recycling was inhibited and consistent with the large increase in presynaptic vesicles. Moreover, we investigated changes in serum exosomes after 2.856 and 9.375 GHz microwave exposure. The results showed that long-term 2.856 GHz microwave exposure could induce a decrease in calcineurin subunit B type 1 and cytochrome b-245 heavy chain in serum exosomes. While the 9.375 GHz long-term microwave exposure induced a decrease in proteins (synaptophysin-like 1, ankyrin repeat and rabankyrin-5, protein phosphatase 3 catalytic subunit alpha and sodium-dependent phosphate transporter 1) in serum exosomes. In summary, long-term microwave exposure could lead to different degrees of spatial learning and memory impairment, EEG disturbance, structural damage to the hippocampus, and differential expression of hippocampal tissue and serum exosomes.


Subject(s)
Cognition , Microwaves , Cognition/radiation effects , Hippocampus/metabolism , Hippocampus/radiation effects , Microwaves/adverse effects , Animals
4.
Environ Sci Pollut Res Int ; 30(13): 37427-37439, 2023 Mar.
Article in English | MEDLINE | ID: mdl-36574118

ABSTRACT

A certain power of microwave radiation could cause changes in the nervous, cardiovascular, and other systems of the body, and the brain was a sensitive target organ of microwave radiation injury. Studies have shown that microwaves can impair cognitive functions in humans and animals, such as learning and memory, attention, and orientation. The dose-dependent effect of microwave radiation is still unclear. Our study aimed to investigate the effects of 1.5-GHz microwaves with different average power densities on locative learning and memory abilities, hippocampal structure, and related N-methyl D-aspartate receptor (NMDAR) signalling pathway proteins in rats. A total number of 140 male Wistar rats were randomly divided into four groups: S group (sham exposure), L5 group (1.5-GHz microwaves with average power density = 5 mW/cm2), L30 group (1.5-GHz microwaves with average power density = 30 mW/cm2), and L50 group (1.5-GHz microwaves with average power density = 50 mW/cm2). Changes in spatial learning and memory, EEG activity, hippocampal structure, and NMDAR signalling pathway molecules were detected from 6 h to 28 d after microwave exposure. After exposure to 1.5-GHz microwaves, rats in the L30 and L50 groups showed impaired spatial memory, inhibited EEG activity, pyknosis and hyperchromatism of neuron nucleus, and changes in NMDAR subunits and downstream signalling molecules. In conclusion, 1.5-GHz microwaves with an average power density of 5, 30, and 50 mW/cm2 could induce spatial memory dysfunction, hippocampal structure changes, and changes in protein levels in rats, and there was a defined dose-dependent effect.


Subject(s)
Microwaves , Spatial Memory , Humans , Rats , Male , Animals , Rats, Wistar , Receptors, N-Methyl-D-Aspartate/metabolism , Hippocampus/metabolism , Memory Disorders
5.
Ecotoxicol Environ Saf ; 243: 113983, 2022 Sep 15.
Article in English | MEDLINE | ID: mdl-35985199

ABSTRACT

This study aimed to elucidate the effects and biological targets sensitive to simultaneous 1.5 and 4.3 GHz microwave exposure in rats. A total of 120 male Wistar rats were divided randomly into four groups: the sham (S group), 1.5 GHz microwave exposure (L group), 4.3 GHz microwave exposure (C group) and simultaneous 1.5 and 4.3 GHz microwave exposure (LC group) groups. Spatial learning and memory, cortical electrical activity, and hippocampal ultrastructure were assessed by the Morris Water Maze, electroencephalography, and transmission electron microscopy, respectively. Additionally, serum exosomes were isolated by ultracentrifugation and assessed by Western blotting, nanoparticle tracking and transmission electron microscopy. The serum exosome protein content was assessed by label-free quantitative proteomics. Impaired spatial learning and memory decreased cortical excitability, and damage to the hippocampal ultrastructure were observed in groups exposed to microwaves, especially the L and LC groups. A total of 54, 145 and 296 exosomal proteins were differentially expressed between the S group and the L, C and LC groups, respectively. These differentially expressed proteins were involved in the synaptic vesicle cycle and SNARE interactions during vesicular transport. Additionally, VAMP8, Syn7 and VMAT are potential serum markers of simultaneous microwave exposure. Thus, exposure to 1.5 and 4.3 GHz microwaves induced impairments in spatial learning and memory, and simultaneous microwave exposure had the most severe effects.


Subject(s)
Exosomes , Microwaves , Animals , Blood Proteins/metabolism , Hippocampus , Male , Maze Learning , Microwaves/adverse effects , Rats , Rats, Wistar , Spatial Learning
6.
Bioelectromagnetics ; 43(5): 336-346, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35544783

ABSTRACT

A large number of studies on the biological effects of microwaves are carried out using rodents and cells, but the conditions are difficult to control, and the irradiation period is short; the results obtained have always been controversial and difficult to reproduce. In this study, we expose nematodes to an electromagnetic environment for a long-term and multigeneration period to explore the possible biological effects. Wild-type N2 strains of Caenorhabditis elegans are exposed to 9.4 GHz microwaves at a specific adsorption rate of 4 W/kg for 10 h per day from L1 larvae to adults. Then, adult worms are washed off, and the laid eggs are kept to hatch L1 larvae, which are continuously exposed to microwaves until passing through 20 generations. The worms of the 10th, 15th, and 20th generations are collected for index detection. Interestingly, we found that the fecundity of C. elegans decreased significantly in the exposed group from the 15th generation. At the same time, we found that the growth of C. elegans decreased, motility decreased, and oxidative stress occurred in the exposed group from the 10th generation, which may play roles in the decreased spawning in worms. We preliminarily believe that the microwave energy received by worms leads to oxidative stress, which causes a decrease in the spawning rate, and the underlying mechanism needs to be further studied. © 2022 Bioelectromagnetics Society.


Subject(s)
Caenorhabditis elegans , Microwaves , Animals , Caenorhabditis elegans/radiation effects , Electromagnetic Phenomena
7.
Front Public Health ; 10: 802386, 2022.
Article in English | MEDLINE | ID: mdl-35252088

ABSTRACT

The nervous system is a sensitive target of electromagnetic radiation (EMR). Chronic microwave exposure can induce cognitive deficits, and 5-HT system is involved in this effect. Genetic polymorphisms lead to individual differences. In this study, we evaluated whether the single-nucleotide polymorphism (SNP) rs198585630 of 5-HT1A receptor is associated with cognitive alterations in rats after microwave exposure with a frequency of 2.856 GHz and an average power density of 30 mW/cm2. Rats were exposed to microwaves for 6 min three times a week for up to 6 weeks. PC12 cells and 293T cells were exposed to microwaves for 5 min up to 3 times at 2 intervals of 5 min. Transcriptional activity of 5-HT1A receptor promoter containing rs198585630 C/T allele was determined in vitro. Electroencephalograms (EEGs), spatial learning and memory, and mRNA and protein expression of 5-HT1A receptor were evaluated in vivo. We demonstrated that transcriptional activity of 5-HT1A receptor promoter containing rs198585630 C allele was higher than that of 5-HT1A receptor promoter containing T allele. The transcriptional activity of 5-HT1A receptor promoter was stimulated by 30 mW/cm2 microwave exposure, and rs198585630 C allele was more sensitive to microwave exposure, as it showed stronger transcriptional activation. Rats carrying rs198585630 C allele exhibited increased mRNA and protein expression of 5-HT1A receptor and were more susceptible to 30 mW/cm2 microwave exposure, showing cognitive deficits and inhibition of brain electrical activity. These findings suggest SNP rs198585630 of the 5-HT1A receptor is an important target for further research exploring the mechanisms of hypersensitivity to microwave exposure.


Subject(s)
Microwaves , Receptor, Serotonin, 5-HT1A , Animals , Cognition , Microwaves/adverse effects , Polymorphism, Genetic , Promoter Regions, Genetic/genetics , RNA, Messenger , Rats , Rats, Wistar , Receptor, Serotonin, 5-HT1A/genetics
8.
Bioelectromagnetics ; 43(1): 5-13, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34962293

ABSTRACT

Because of the extensive application of electromagnetic technology, its health impact on humans has attracted widespread attention. Due to the lack of a model organism with a stable response to electromagnetic waves, the research conclusions on the biological effects of electromagnetic waves have been vague. Therefore, the aim of this study was to investigate the effects of irradiation by pulsed 9.4 GHz high-power microwaves with a peak power density of 2126 W/cm2 using Caenorhabditis elegans. The development, movement, egg production, ROS, and lifespan of C. elegans were detected at different times after irradiation with different repetitive frequencies of 10, 20, and 50 Hz for 30 min. The results indicated that no obvious changes in basic life indices were induced compared with the sham radiation group, but the survival rate of positive control was significantly decreased compared with other groups, which is of interest for microwave protection research based on C. elegans and provides data for updating safety standards with respect to pulsed high-peak power microwave. © 2021 Bioelectromagnetics Society.


Subject(s)
Caenorhabditis elegans , Microwaves , Animals , Electromagnetic Phenomena , Humans
9.
Micromachines (Basel) ; 12(5)2021 May 06.
Article in English | MEDLINE | ID: mdl-34066359

ABSTRACT

A novel bonding process using Ag agglomerates paste prepared by Ag2O reduction has been proposed, which solved the problem of Cu substrate oxidation in the conventional Ag2O sintering process for Cu-Cu bonding. By applying the Ag agglomerate paste to Ag-Ag bonding, a shear strength of 28.3 MPa at 150 °C was obtained. Further studies showed that the optimum sintering temperature was at 225 °C, and a shear strength of 46.4 MPa was obtained. In addition, a shear strength of 20 MPa was obtained at 225 °C for Cu-Cu bonding. Compared to common Ag pastes, the results in this paper revealed that the sintering behavior of Ag agglomerates was unique, and the sintering mechanisms for Ag-Ag and Cu-Cu bonding were also discussed.

10.
Electromagn Biol Med ; 40(2): 311-320, 2021 Apr 03.
Article in English | MEDLINE | ID: mdl-33688776

ABSTRACT

High-power microwaves (HPMs) have been reported to have hazardous effects on multiple human and animal organs. However, the biological effects of 1.5-GHz HPMs on the reproductive system are not clear. Here, we studied the effects of 1.5 -GHz HPM whole-body exposure on the pathological structure of the testicles and changes in spermatozoa mobility. C57BL/6 mice of groups L, M, and H were exposed to 1.5-GHz HPM fields for two 15-min intervals at the average specific absorption rates of 3, 6, and 12 W/Kg, respectively. The pathological structure of the testicles and spermatozoa, as well as serum testosterone and sperm motility parameters, were evaluated at 6 h, 1 d, 3 d, and 7 d after exposure. As a result, there were no significant pathological or ultrastructural changes in the testicles or spermatozoa and serum testosterone levels. The number of progressively motile spermatozoa, curvilinear velocity, linear velocity, and average path velocity of the exposure group increased at 6 h, decreased at 1 d, and recovered at 3 d. The opposite results were considered a stress response to the thermal effect of the microwaves. Our results indicated that 1.5-GHz HPM whole-body exposure in mice at SARs of 3, 6, and 12 W/Kg for 30 min did not cause obvious damage to the reproductive system.


Subject(s)
Microwaves , Sperm Motility , Animals , Male , Mice , Mice, Inbred C57BL , Spermatozoa
11.
Protein Expr Purif ; 182: 105844, 2021 06.
Article in English | MEDLINE | ID: mdl-33592251

ABSTRACT

The human autophagy-related protein ATG7 (hATG7), an E1-like ubiquitin enzyme, activates two ubiquitin-like proteins, LC3 (Atg8) and Atg12, and promotes autophagosome formation. While hATG7 plays an essential role for the autophagy conjugation system, the production of full-length functional hATG7 in bacterial systems remains challenging. Previous studies have demonstrated that the HIV-1 virus-encoded Tat peptide ('GRKKRRQRRR') can increase the yield and solubility of heterologous proteins. Here, functional full-length hATG7 was expressed using the pET28b-Tat expression vector in the Escherichia coli BL21 (DE3) strain. Recombinant hATG7 protein aggregated as inclusion bodies while expressed with widely used prokaryotic expression plasmids. In contrast, the solubility of Tat-tagged hATG7 increased significantly with prolonged time compared to Tat-free hATG7. The recombinant proteins were purified to >90% homogeneity under native conditions with a single step of affinity chromatography purification. The results of in vitro pull-down and LC3B-I lipidation assays showed that Tat-tagged hATG7 directly interacted with LC3B-I and promoted LC3B-I lipidation, suggesting that Tat-tagged hATG7 has significant catalytic activity. Overall, this study provides a novel method for improving the functional expression of full-length hATG7 in bacterial systems by fusion with the Tat peptide, a process which may be applied in future studies of hATG7 structure and function.


Subject(s)
Autophagy-Related Protein 7 , Escherichia coli , Gene Expression , HIV-1/genetics , Recombinant Fusion Proteins , tat Gene Products, Human Immunodeficiency Virus , Autophagy-Related Protein 7/biosynthesis , Autophagy-Related Protein 7/chemistry , Autophagy-Related Protein 7/genetics , Autophagy-Related Protein 7/isolation & purification , Escherichia coli/genetics , Escherichia coli/metabolism , Humans , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/isolation & purification , tat Gene Products, Human Immunodeficiency Virus/biosynthesis , tat Gene Products, Human Immunodeficiency Virus/chemistry , tat Gene Products, Human Immunodeficiency Virus/genetics , tat Gene Products, Human Immunodeficiency Virus/isolation & purification
12.
Curr Issues Mol Biol ; 44(1): 206-221, 2021 Dec 31.
Article in English | MEDLINE | ID: mdl-35723394

ABSTRACT

With the wide application of microwave technology, concerns about its health impact have arisen. The signal transmission mode of the central nervous system and neurons make it particularly sensitive to electromagnetic exposure. It has been reported that abnormal release of amino acid neurotransmitters is mediated by alteration of p-SYN1 after microwave exposure, which results in cognitive dysfunction. As the phosphorylation of SYN1 is regulated by different kinases, in this study we explored the regulatory mechanisms of SYN1 fluctuations following microwave exposure and its subsequent effect on GABA release, aiming to provide clues on the mechanism of cognitive impairment caused by microwave exposure. In vivo studies with Timm and H&E staining were adopted and the results showed abnormality in synapse formation and neuronal structure, explaining the previously-described deficiency in cognitive ability caused by microwave exposure. The observed alterations in SYN1 level, combined with the results of earlier studies, indicate that SYN1 and its phosphorylation status (ser-553 and ser62/67) may play a role in the abnormal release of neurotransmitters. Thus, the role of Cdk5, the upstream kinase regulating the formation of p-SYN1 (ser-553), as well as that of MEK, the regulator of p-SYN1 (ser-62/67), were investigated both in vivo and in vitro. The results showed that Cdk5 was a negative regulator of p-SYN1 (ser-553) and that its up-regulation caused a decrease in GABA release by reducing p-SYN1 (ser-553). While further exploration still needed to elaborate the role of p-SYN1 (ser-62/67) for neurotransmitter release, MEK inhibition had was no impact on p-Erk or p-SYN1 (ser-62/67) after microwave exposure. In conclusion, the decrease of p-SYN1 (ser-553) may result in abnormalities in vesicular anchoring and GABA release, which is caused by increased Cdk5 regulated through Calpain-p25 pathway after 30 mW/cm2 microwave exposure. This study provided a potential new strategy for the prevention and treatment of microwave-induced cognitive dysfunction.

13.
Nat Commun ; 10(1): 2619, 2019 06 13.
Article in English | MEDLINE | ID: mdl-31197175

ABSTRACT

Sleep architecture carries vital information about brain health across the lifespan. In particular, the ability to express distinct vigilance states is a key physiological marker of neurological wellbeing in the newborn infant although systems-level mechanisms remain elusive. Here, we demonstrate that the transition from quiet to active sleep in newborn infants is marked by a substantial reorganization of large-scale cortical activity and functional brain networks. This reorganization is attenuated in preterm infants and predicts visual performance at two years. We find a striking match between these empirical effects and a computational model of large-scale brain states which uncovers fundamental biophysical mechanisms not evident from inspection of the data. Active sleep is defined by reduced energy in a uniform mode of neural activity and increased energy in two more complex anteroposterior modes. Preterm-born infants show a deficit in this sleep-related reorganization of modal energy that carries novel prognostic information.


Subject(s)
Brain/physiology , Infant, Premature/physiology , Models, Biological , Neurodevelopmental Disorders/diagnosis , Sleep/physiology , Electroencephalography , Female , Follow-Up Studies , Humans , Infant , Infant, Newborn , Male , Prognosis , Spatio-Temporal Analysis
14.
Neurology ; 92(20): e2329-e2338, 2019 05 14.
Article in English | MEDLINE | ID: mdl-30971485

ABSTRACT

OBJECTIVE: To determine whether quantitative EEG (QEEG) features predict neurologic outcomes in children after cardiac arrest. METHODS: We performed a single-center prospective observational study of 87 consecutive children resuscitated and admitted to the pediatric intensive care unit after cardiac arrest. Full-array conventional EEG data were obtained as part of clinical management. We computed 8 QEEG features from 5-minute epochs every hour after return of circulation. We developed predictive models utilizing random forest classifiers trained on patient age and 8 QEEG features to predict outcome. The features included SD of each EEG channel, normalized band power in alpha, beta, theta, delta, and gamma wave frequencies, line length, and regularity function scores. We measured outcomes using Pediatric Cerebral Performance Category (PCPC) scores. We evaluated the models using 5-fold cross-validation and 1,000 bootstrap samples. RESULTS: The best performing model had a 5-fold cross-validation accuracy of 0.8 (0.88 area under the receiver operating characteristic curve). It had a positive predictive value of 0.79 and a sensitivity of 0.84 in predicting patients with favorable outcomes (PCPC score of 1-3). It had a negative predictive value of 0.8 and a specificity of 0.75 in predicting patients with unfavorable outcomes (PCPC score of 4-6). The model also identified the relative importance of each feature. Analyses using only frontal electrodes did not differ in prediction performance compared to analyses using all electrodes. CONCLUSIONS: QEEG features can standardize EEG interpretation and predict neurologic outcomes in children after cardiac arrest.


Subject(s)
Electroencephalography/methods , Heart Arrest/therapy , Hypoxia, Brain/diagnosis , Area Under Curve , Child , Child, Preschool , Female , Heart Arrest/complications , Humans , Hypoxia, Brain/etiology , Hypoxia, Brain/physiopathology , Infant , Male , Near Drowning/complications , Prognosis , Prospective Studies , ROC Curve , Reproducibility of Results , Respiratory Insufficiency/complications , Shock/complications , Sudden Infant Death , Wounds and Injuries/complications
15.
J Neural Eng ; 16(2): 026016, 2019 04.
Article in English | MEDLINE | ID: mdl-30560812

ABSTRACT

OBJECTIVE: Closed-loop implantable neural stimulators are an exciting treatment option for patients with medically refractory epilepsy, with a number of new devices in or nearing clinical trials. These devices must accurately detect a variety of seizure types in order to reliably deliver therapeutic stimulation. While effective, broadly-applicable seizure detection algorithms have recently been published, these methods are too computationally intensive to be directly deployed in an implantable device. We demonstrate a strategy that couples devices to cloud computing resources in order to implement complex seizure detection methods on an implantable device platform. APPROACH: We use a sensitive gating algorithm capable of running on-board a device to identify potential seizure epochs and transmit these epochs to a cloud-based analysis platform. A precise seizure detection algorithm is then applied to the candidate epochs, leveraging cloud computing resources for accurate seizure event detection. This seizure detection strategy was developed and tested on eleven human implanted device recordings generated using the NeuroVista Seizure Advisory System. MAIN RESULTS: The gating algorithm achieved high-sensitivity detection using a small feature set as input to a linear classifier, compatible with the computational capability of next-generation implantable devices. The cloud-based precision algorithm successfully identified all seizures transmitted by the gating algorithm while significantly reducing the false positive rate. Across all subjects, this joint approach detected 99% of seizures with a false positive rate of 0.03 h-1. SIGNIFICANCE: We present a novel framework for implementing computationally intensive algorithms on human data recorded from an implanted device. By using telemetry to intelligently access cloud-based computational resources, the next generation of neuro-implantable devices will leverage sophisticated algorithms with potential to greatly improve device performance and patient outcomes.


Subject(s)
Cloud Computing , Electrodes, Implanted , Seizures/diagnosis , Algorithms , Electric Stimulation Therapy , Electroencephalography/instrumentation , Electroencephalography/methods , Humans , Linear Models , Machine Learning , ROC Curve , Seizures/therapy , Telemetry
16.
PLoS Comput Biol ; 14(8): e1006387, 2018 08.
Article in English | MEDLINE | ID: mdl-30133448

ABSTRACT

A user ready, portable, documented software package, NFTsim, is presented to facilitate numerical simulations of a wide range of brain systems using continuum neural field modeling. NFTsim enables users to simulate key aspects of brain activity at multiple scales. At the microscopic scale, it incorporates characteristics of local interactions between cells, neurotransmitter effects, synaptodendritic delays and feedbacks. At the mesoscopic scale, it incorporates information about medium to large scale axonal ranges of fibers, which are essential to model dissipative wave transmission and to produce synchronous oscillations and associated cross-correlation patterns as observed in local field potential recordings of active tissue. At the scale of the whole brain, NFTsim allows for the inclusion of long range pathways, such as thalamocortical projections, when generating macroscopic activity fields. The multiscale nature of the neural activity produced by NFTsim has the potential to enable the modeling of resulting quantities measurable via various neuroimaging techniques. In this work, we give a comprehensive description of the design and implementation of the software. Due to its modularity and flexibility, NFTsim enables the systematic study of an unlimited number of neural systems with multiple neural populations under a unified framework and allows for direct comparison with analytic and experimental predictions. The code is written in C++ and bundled with Matlab routines for a rapid quantitative analysis and visualization of the outputs. The output of NFTsim is stored in plain text file enabling users to select from a broad range of tools for offline analysis. This software enables a wide and convenient use of powerful physiologically-based neural field approaches to brain modeling. NFTsim is distributed under the Apache 2.0 license.


Subject(s)
Brain/physiology , Computational Biology/methods , Nerve Net/physiology , Algorithms , Animals , Axons , Gene Regulatory Networks/genetics , Humans , Models, Theoretical , Neurons/physiology , Normal Distribution , Software
17.
Rev Sci Instrum ; 86(12): 124701, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26724050

ABSTRACT

A method for reflection measurements of High-power Microwave (HPM) antennas excited with overmoded waveguides is proposed and studied systemically. In theory, principle of the method is proposed and the data processing formulas are developed. In simulations, a horn antenna excited by a TE11 mode exciter is examined and its reflection is calculated by CST Microwave Studio and by the method proposed in this article, respectively. In experiments, reflection measurements of two HPM antennas are conducted, and the measured results are well consistent with the theoretical expectations.

18.
Rev Sci Instrum ; 83(10): 103304, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23126760

ABSTRACT

After repeatedly operation of a triode virtual cathode oscillator, the surface morphology of anode grid is studied by a scanning electron microscope. It is found that there are many quasi-periodic sawteeth formed on the anode grid, which are about 300-500 µm in height, ~200 µm in width, and 150-200 µm in period. The formation of this sawteeth implies that there is possible Rayleigh-Taylor-like instability on the anode grid during the irradiation by high-current relativistic electron beam. These sawteeth enhance the electric field on anode grid, leading to more feasible of anode plasma generation, and more rapidly expansion of that plasma. As a result, the electron transmissivity of anode grid is decreased, the output microwave power of the virtual cathode oscillator is lowered and its operational performance is degraded.

19.
Zhongguo Zhong Yao Za Zhi ; 34(8): 965-8, 2009 Apr.
Article in Chinese | MEDLINE | ID: mdl-19639776

ABSTRACT

OBJECTIVE: Study on the of content variety of flavonoids in the course of processing Cortex Moutan,and discuss the preparation mechanism of Cortex Moutan Carbonisatum (CMC). METHOD: HPLC method was developed for the determination of flavonoids in various extent of CMC, the sample was extracted by ultrasound 30 min twice along with ethanol 50 mL. Chromatographic conditions were as follows: wavelength 360 nm, gradient eluant of methanol--0.5% per hundred trifluoroacetic acid. RESULT: The content of the three flavonoids cuts down along with the processing time and the rising temperature. CONCLUSION: The impact of various extent of processing on flavonoids content of the CMC is very great. The overall trend is that high temperature and long time lead to the lower of the content of flavonoids. This provides a basis data for the further study on the hemostatic mechanism and quality control of CMC.


Subject(s)
Drugs, Chinese Herbal/chemistry , Flavonoids/chemistry , Flavonoids/isolation & purification , Paeonia/chemistry , Chromatography, High Pressure Liquid , Flavonols/chemistry , Flavonols/isolation & purification , Kaempferols/chemistry , Kaempferols/isolation & purification , Quercetin/chemistry , Quercetin/isolation & purification , Temperature
20.
Zhongguo Zhong Yao Za Zhi ; 34(19): 2463-5, 2009 Oct.
Article in Chinese | MEDLINE | ID: mdl-20067013

ABSTRACT

OBJECTIVE: To establish the analytical method of the HPLC fingerprint of Cortex Moutan Carbonisatum and offer the evidence for quality control and quality evaluation of carbonized Cortex Moutan accordingly. METHOD: Ten batches of Cortex Moutan Carbonisatum were measured by HPLC with Paeonol as a reference substance and the HPLC analysis was performed on a Hedera ODS-3 Chromatographic Column (4.6 mm x 150 mm, 5 microm), with methanol to Acetonitrile (1:1) and 0.5% trifluoroacetic acid solution as mobile phase in gradient mode and the detection wavelength was at 258 nm. RESULT: The common mode of the HPLC fingerprints were set up. There were 11 common peaks in the fingerprint of ten samples, and the similar degrees to the ten batches were between 0.830-0.991. CONCLUSION: The method is simple, accurate and have a good reaptability. And the quality of Cortex Moutan Carbonisatum can be controlled effectively by the HPLC fingerprint.


Subject(s)
Chromatography, High Pressure Liquid/methods , Drugs, Chinese Herbal/analysis , Paeonia/chemistry
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