Electroacupuncture modulates the activity of the hippocampus-nucleus tractus solitarius-vagus nerve pathway to reduce myocardial ischemic injury

The hippocampus is involved in the regulation of the autonomic nervous system,together with the hypothalamus and brainstem nuclei,such as the paraventricular nucleus and nucleus tractus solitarius.The vagus nerve-nucleus tractus solitarius pathway has an important role in cardiovascular reflex regulation.Myocardial ischemia has been shown to cause changes in the autonomic nervous system,affecting the dynamic equilibrium of the sympathetic and vagal nerves.However,it remains poorly understood how the hippocampus communicates with brainstem nuclei to regulate the autonomic nervous system and alleviate myocardial ischemic tissue damage.A rat model of acute myocardial ischemia（AMI） was made by ligating the left anterior descending branch of the coronary artery.Three days before ischemia,the hippocampal CA1 region was damaged.Then,3 days after ischemia,electroacupuncture（EA） at Shenmen（HT7）-Tongli（HT5） was performed（continuous wave,1 m A,2 Hz,duration of 30 minutes）.Cluster analysis of firing patterns showed that one type of neuron was found in rats in the sham and AMI groups.Three types of neurons were observed in the AMI ＋ EA group.Six types of neurons were found in the AMI ＋ EA ＋ Lesion group.Correlation analysis showed that the frequency of vagus nerve discharge in each group was negatively correlated with heart rate（HR）（P 〈 0.05,r =-0.424）,and positively correlated with mean arterial pressure（MAP）（P 〈 0.05,r = 0.40987） and the rate-pressure product（RPP）（P 〈 0.05,r = 0.4252）.The total frequency of the nucleus tractus solitarius discharge in each group was positively correlated with vagus nerve discharge（P 〈 0.01,r = 0.7021）,but not with hemodynamic index（HR： P 〉 0.05,r =-0.03263; MAP： P 〉 0.05,r =-0.08993; RPP： P 〉 0.05,r =-0.03263）.Some neurons（Neuron C） were negatively correlated with vagus nerve discharge,HR,MAP and RPP in the AMI ＋ EA group（vagus nerve discharge： P 〈 0.05,r =-0.87749; HR： P 〈 0.01,r =-0.91902; MAP： P 〈 0.05,r =-0.85691; RPP： P 〈 0.01,r =-0.91902）.Some neurons（Neurons C,D and E） were positively correlated with vagus nerve discharge,HR,MAP and RPP in the AMI ＋ EA ＋ Lesion group（vagus nerve discharge： P 〈 0.01,r = 0.8905,P 〈 0.01,r = 0.9725,P 〈 0.01,r = 0.9054; HR： P 〈 0.01,r = 0.9347,P 〈 0.01,r = 0.9089,P 〈 0.05,r = 0.8247; MAP： P 〈 0.05,r = 0.8474,P 〈 0.01,r = 0.9691,P 〈 0.01,r = 0.9027; RPP： P 〈 0.05,r = 0.8637,P 〈 0.01,r = 0.9407,P 〈 0.01,r = 0.9027）.These findings show that the hippocampus-nucleus tractus solitarius-vagus nerve pathway is involved in the cardioprotective effect of EA at the heart meridian.Some interneurons in the nucleus tractus solitarius may play a particularly important role in the cardiomodulatory process.

Contralateral S1 function is involved in electroacupuncture treatment-mediated recovery after focal unilateral M1 infarction

Acupuncture at acupoints Baihui(GV20)and Dazhui(GV14)has been shown to promote functional recovery after stroke.However,the contribution of the contralateral primary sensory cortex(S1)to recovery remains unclear.In this study,unilateral local ischemic infarction of the primary motor cortex(M1)was induced by photothrombosis in a mouse model.Electroacupuncture(EA)was subsequently performed at acupoints GV20 and GV14 and neuronal activity and functional connectivity of contralateral S1 and M1 were detected using in vivo and in vitro electrophysiological recording techniques.Our results showed that blood perfusion and neuronal interaction between contralateral M1 and S1 is impaired after unilateral M1 infarction.Intrinsic neuronal excitability and activity were also disturbed,which was rescued by EA.Furthermore,the effectiveness of EA treatment was inhibited after virus-mediated neuronal ablation of the contralateral S1.We conclude that neuronal activity of the contralateral S1 is important for EA-mediated recovery after focal M1 infarction.Our study provides insight into how the S1-M1 circuit might be involved in the mechanism of EA treatment of unilateral cerebral infarction.The animal experiments were approved by the Committee for Care and Use of Research Animals of Guangzhou University of Chinese Medicine(approval No.20200407009)April 7,2020.

Compact microring resonator based on ultralow-loss multimode silicon nitride waveguide

Silicon nitride(Si3N4)waveguides with high confinement and low loss have been widely used in integrated nonlinear photonics.Indeed,state-of-the-art ultralow-loss Si3N4 waveguides are all fabricated using complex fabrication processes,and all of those reported that high Q microring resonators(MRRs)are fabricated in laboratories.We propose and demonstrate an ultralow-loss Si3N4 racetrack MRR by shaping the mode using a uniform multimode structure to reduce its overlap with the waveguide.The MRR is fabricated by the standard multi project wafer(MPW)foundry process.It consists of two multimode straight waveguides(MSWs)connected by two multimode waveguide bends(MWBs).In particular,the MWBs are based on modified Euler bends,and an MSW directional coupler is used to avoid higher-order mode excitation.In this way,although a multimode waveguide is used in the MRR,only the fundamental mode is excited and transmitted with ultralow loss.Meanwhile,thanks to the 180 deg Euler bend,a compact chip footprint of 2.226 mm perimeter with an effective radius as small as 195μm and a waveguide width of 3μm is achieved.Results show that based on the widely used MPW process,a propagation loss of only 3.3 dB∕m and a mean intrinsic Q of around 10.8 million are achieved for the first time.

毛刺状氮化铌纤维制备及其电化学性能研究

以五氯化铌为铌源,利用静电纺丝、溶剂热和氨气还原技术相结合制备了具有毛刺状的氮化铌纤维,浸泡盐酸多巴胺在纤维表面包覆纳米碳。结果表明,制备纤维为四方Nb4N5相,纤维表面具有毛刺状结构,有助于增加接触界面,提高有效电荷转移效率,提高样品的比电容,可达212.16 F·g^(-1)。

Broadband continuous-wave mid-infrared wavelength conversion in high-Q silicon microring resonators

The four-wave mixing(FWM)effect offers promise to generate or amplify light at wavelengths where achieving substantial gain is challenging,particularly within the mid-infrared(MIR)spectral range.Here,based on the commonly used 340 nm silicon-on-insulator(SOI)platform,we experimentally demonstrate high-efficiency and broadband wavelength conversion using the FWM effect in a high-Q silicon microring resonator pumped by a continuous-wave(CW)laser in the 2μm waveband.The microring resonator parameters are carefully optimized for effective phase-matching to obtain high conversion efficiency(CE)with broad bandwidth.The loaded quality(Ql)factor of the fabricated microring resonator is measured to be 1.11×105,at a resonance wavelength of 1999.3 nm,indicating low propagation losses of 1.68 dB/cm.A maximum CE of−15.57 dB is achieved with a low input pump power of only 4.42 dBm,representing,to our knowledge,the highest on-chip CE demonstrated to date under the CW pump in the MIR range.Furthermore,broadband wavelength conversion can be observed across a 140.4 nm wavelength range with a CE of−19.32 dB,and simulations indicate that the conversion bandwidth is over 400 nm.This work opens great potential in exploiting widely tunable on-chip sources using highefficiency wavelength conversion,particularly leveraging the advantages of the SOI platform in integrated photonics across the 2μm MIR range.

Tribological behavior of a Ni-WS2 composite coating across wide temperature ranges

In order to reduce the friction coefficient of a pure nickel coating and extend the lifetime of metal parts under extreme friction conditions,a series of Ni-based WS2-composite solid lubrication coating containing different WS2 concentrations were prepared on a 45#mild carbon steel substrate by electroplating.The cyclic voltammetry method was used to investigate the electroplating regulation of the Ni-WS2 composite coatings.X-ray diffraction(XRD) and scanning electron microscopy(SEM) were used to analyze the microstructures and wear surfaces of the composite coatings,the tribological properties and wear mechanisms of the composite coatings with different WS2 concentrations.The results show that the addition of WS2 can promote the cathode polarization of the electroplating process,and the polarization degree goes up with the increase in WS2 concentrations.The friction coefficient of Ni-composite coatings significantly decreases by the addition of WS2 particles.The lowest friction coefficient at room temperature is obtained at a value around 0.01-0.03 from the coating deposited in the electrolyte solution with a 30g·L^-1 WS2 concentration.The friction coefficient of the Ni-WS2 composite coating remains in 0.01-0.03 with the increase in temperature from room temperature to 300℃.When the temperature goes up to 500℃,the friction coefficient manifests a continuous increase to 0.12,because WS2 is gradually oxidized into WO3 and therefore loses its lubrication ability.

Noise reduction in cavity flow by addition of porous media

Self-sustained oscillation and the sound radiation of flow over an open cavity is of great importance in nature and industry.Influences of filled porous media in the cavity are investigated numerically by using a lattice Boltzmann method in two-dimensional space.It is shown that the outcomes of the porous patch depend on the location of the patch and the original flow mode,namely shear layer(SL)and wake mode(WM).For SL flow,the porous patch either damps the vortical flow or suppresses the generation of the secondary vortex sheet on the wall.The later effect destabilizes the SL.Consequently,the radiated sound is reduced as the patch is on the trailing edge,and increased with porous patch on the floor,respectively.For flow in WM,a transition from WM to SL mode is found when the porous patch is set either on the floor or behind the leading wall.In the cases,the recirculating flow on large scale is blocked significantly due to the porous patch,therefore,the WM flow is not sustained.On the other hand,the porous patch on the trailing edge slightly weakens the sound due to dissipation.The study shows that assembling of porous media in the flow field decreases the radiated sound level only if it is done carefully.

Superhydrophobic Fe-based amorphous coating fabricated by detonation spraying with excellent anti-corrosion and self-cleaning properties

Amorphous alloys without crystalline defects(dislocation,crystal boundary)are ideal hydrophobic coating materials due to their low surface energy.This work used a synergistic method of detonation spraying and surface modification to obtain the superhydrophobic Febased amorphous coatings with high hardness and dense structure on the Q 235 substrate.The results showed that the water contact angles(WCA)of the superhydrophobic coating was 160°±3.6°,and water droplets could bounce off the superhydrophobic coating surface,illustrating the excellent self-cleaning performance of coating.Notably,the corrosion current density(i_(corr))of the superhydrophobic coating further decreased by 2 orders of magnitude down to8.008×10^(-8)A·cm^(-2)compared to the as-deposited coating with 5.473×10^(-6)A·cm^(-2);the corrosion potential(E_(corr))of the superhydrophobic coating shifted by 34 mV to the positive side compared with that of the as-deposited coating(-310 mV).Likewise,the impedance modulus|Z|values of the superhydrophobic coating increased by nearly2 orders of magnitude up to 1×10^(5.6)compared to the asdeposited coating with 1×10^(3.8).Even through lasting immersion in NaCl for 10 days,|Z|values of the superhydrophobic coating were still much higher than those of the as-deposited coating.The superhydrophobic Fe-based amorphous coatings could respond to their applications under extreme conditions due to their excellent hydrophobicity and self-cleaning properties,illustrating their promising future in aerospace,automotive,and machinery industries.

Statistical Inference for the Covariates-driven Binomial AR(1)Process

The binomial autoregressive(BAR(1))process is very useful to model the integer-valued time series data defined on a finite range.It is commonly observed that the autoregressive coefficient is assumed to be a constant.To make the BAR(1)model more practical,this paper introduces a new random coefficient binomial autoregressive model,which is driven by covariates.Basic probabilistic and statistical properties of this model are discussed.Conditional least squares and conditional maximum likelihood estimators of the model parameters are derived,and the asymptotic properties are obtained.The performance of these estimators is compared via a simulation study.An application to a real data example is also provided.The results show that the proposed model and methods perform well for the simulations and application.