Gabapentinoid drugs(pregabalin and gabapentin) have been successfully used in the treatment of neuro pathic pain and in focal seizure prevention.Recent research has demonstrated their potent activities in modulating n...Gabapentinoid drugs(pregabalin and gabapentin) have been successfully used in the treatment of neuro pathic pain and in focal seizure prevention.Recent research has demonstrated their potent activities in modulating neurotransmitter release in neuronal tissue,oxidative stress,and inflammation,which matches the mechanism of action via voltage-gated calcium channels.In this review,we briefly elaborate on the medicinal history and ligand-binding sites of gabapentinoids.We systematically summarize the preclinical and clinical research on gabapentinoids in stroke,including ischemic stro ke,intracerebral hemorrhage,subarachnoid hemorrhage,seizures after stro ke,cortical spreading depolarization after stroke,pain after stroke,and nerve regeneration after stro ke.This review also discusses the potential to rgets of gabapentinoids in stroke;however,the existing results are still unce rtain regarding the effect of gabapentinoids on stroke and related diseases.Further preclinical and clinical trials are needed to test the therapeutic potential of gabapentinoids in stroke.Therefore,gabapentinoids have both opportunities and challenges in the treatment of stroke.展开更多
Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events a...Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events are significantly slower than the excitatory postsynaptic currents.Parameters of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto rs.Astrocytes are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback loop.Mostly as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological conditions.There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level.These events often occur in synchro ny on neurons located in the same astrocytic domain.Besides synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity.In addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory inputs.Of note,there might be important regionspecific differences in the roles and actions triggering slow inward currents.In greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological ones.Slow inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural networks.Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes.These events are related to epilepsy,but also found in Alzheimer's disease,Parkinson's disease,and stroke,leading to the decline of cognitive functions.Events with features overlapping with slow inward currents(excitatory,N-methyl-Daspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke,traumatic brain injury,or epilepsy.One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation.However,to state this,more experimental evidence from greater neuronal networks or the level of the individual is needed.In this review,I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.展开更多
During brain ischemia,excitotoxicity and peri-infarct depolarization injuries occur and cause cerebral tissue damage.Indeed,anoxic depolarization,consisting of massive neuronal depolarization due to the loss of membra...During brain ischemia,excitotoxicity and peri-infarct depolarization injuries occur and cause cerebral tissue damage.Indeed,anoxic depolarization,consisting of massive neuronal depolarization due to the loss of membrane ion gradients,occurs in vivo or in vitro during an energy failure.The neuromodulator adenosine is released in huge amounts during cerebral ischemia and exerts its effects by activating specific metabotropic receptors,namely:A_(1),A_(2A),A_(2B),and A_(3).The A_(2A)receptor subtype is highly expressed in striatal medium spiny neurons,which are particularly susceptible to ischemic damage.Evidence indicates that the A2Areceptors are upregulated in the rat striatum after stroke and the selective antagonist SCH58261 protects from exaggerated glutamate release within the first 4 hours from the insult and alleviates neurological impairment and histological injury in the following 24 hours.We recently added new knowledge to the mechanisms by which the adenosine A2Areceptor subtype participates in ischemia-induced neuronal death by performing patch-clamp recordings from medium spiny neurons in rat striatal brain slices exposed to oxygen and glucose deprivation.We demonstrated that the selective block of A2Areceptors by SCH58261 significantly reduced ionic imbalance and delayed the anoxic depolarization in medium spiny neurons during oxygen and glucose deprivation and that the mechanism involves voltage-gated K+channel modulation and a presynaptic inhibition of glutamate release by the A2Areceptor antagonist.The present review summarizes the latest findings in the literature about the possibility of developing selective ligands of A2Areceptors as advantageous therapeutic tools that may contribute to counteracting neurodegeneration after brain ischemia.展开更多
Ultraviolet(UV)photodetectors are extensively adopted in the fields of the Internet of Things,optical communications and imaging.Nowadays,with broadening the application scope of UV photodetectors,developing integrate...Ultraviolet(UV)photodetectors are extensively adopted in the fields of the Internet of Things,optical communications and imaging.Nowadays,with broadening the application scope of UV photodetectors,developing integrated devices with more functionalities rather than basic photo-detecting ability are highly required and have been triggered ever-growing interest in scientific and industrial communities.Ferroelectric thin films have become a potential candidate in the field of UV detection due to their wide bandgap and unique photovoltaic characteristics.Additionally,ferroelectric thin films perform excellent dielectric,piezoelectric,pyroelectric,acousto-optic effects,etc.,which can satisfy the demand for the diversified development of UV detectors.In this review,according to the different roles of ferroelectric thin films in the device,the UV photodetectors based on ferroelectric films are classified into ferroelectric depolarization field driven type,ferroelectric depolarization field and built-in electric field co-driven type,and ferroelectric field enhanced type.These three types of ferroelectric UV photodetectors have great potential and are expected to promote the development of a new generation of UV detection technology.At the end of the paper,the advantages and challenges of three types of ferroelectric UV photodetectors are summarized,and the possible development direction in the future is proposed.展开更多
The kinetics of I→N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polym...The kinetics of I→N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.展开更多
Temporal lobe epilepsy(TLE) is a common type of epilepsy and is not well controlled by current treatments.The frequent failure to treat TLE may be due to our lack of precise cellular/circuit mechanisms underlying TLE....Temporal lobe epilepsy(TLE) is a common type of epilepsy and is not well controlled by current treatments.The frequent failure to treat TLE may be due to our lack of precise cellular/circuit mechanisms underlying TLE.The early series of our studies have proved the success of low-frequency stimulation treatment for epilepsy,which was mainly depending on the stimulation target,the stimulation frequency and stimulation time(the therapeutic-window phenomenon).Now,by using optogenetics,viral tracing,multiple-channel EEG analysis,imaging,electrophysiology and pharmacology strategies,we are continued to investigate the circuit mechanism of therapeutic deep brain stimulation,and found that entorhinal principal neurons mediate antiepileptic ″ glutamatergic-GABAergic″ neuronal circuit for brain stimulation treatments of epilepsy.Meanwhile,we are currently focusing on the interplay of inhibitory and excitatory network in the key input/output regions of the hippocampus that related to the generation of in TLE.Specially,we found that depolarized GABAergic signaling in subicular microcircuit mediates generalized seizures in TLE and a direct septal cholinergic circuit attenuates TLE through driving hippocampal somatostatin inhibition.These findings may be of therapeutic interest in understanding the pathological neuronal circuitry in TLE and further the development of novel therapeutic approaches or drug targets.展开更多
Whether the ATP sensitive potassium channel opener pinacidil can provide myocardial protective effects in prolonged isolated global ischemic rat heart was investigated. On modified isolated rat working heart model, 40...Whether the ATP sensitive potassium channel opener pinacidil can provide myocardial protective effects in prolonged isolated global ischemic rat heart was investigated. On modified isolated rat working heart model, 40 hearts were divided into four groups randomly: Hyperpolarized arrest H K solution containing pinacidil (50 μmol/L) (P1 and P2) and depolarized arrest St. Thomas’ solution (S1 and S2) subjected to 15 ℃ hypothermia, 60 min (P1 and S1) or 120 min (P1 and S2) of ischemia and 30 min reperfusion. The experimental indices included cardioplegic efficiency, cardiac function, coronary blood flow, myocardial enzyme release, myocardial water and ATP content. Hyperpolarized arrest provided significantly better recovery of cardiac function than depolarized arrest. Postischemic coronary flow and myocardial ATP content were higher. The arrest time of electro mechanical activities were longer than depolarized arrest. There were no differences among the groups in myocardial water contents. The hyperpolarized arrest solution containing pinacidil can provide a marked myocardial protective effect during prolonged hypothermic myocardial ischemia.展开更多
Ti-bearing slag(TiO2>20 wt%)is a valuable titanium secondary resource.The extraction of titanium from the slag is difficult due to the complex composition and structure.Although molten oxide electrolysis is conside...Ti-bearing slag(TiO2>20 wt%)is a valuable titanium secondary resource.The extraction of titanium from the slag is difficult due to the complex composition and structure.Although molten oxide electrolysis is considered as a promising method,silicon will be preferentially electroreduced compared to titanium due to low theoretical decomposition voltage.In this work,a liquid copper cathode is used to selectively extract titanium from molten Al2O3-MgO-CaO-TiO2-SiO2 electrolyte.It is found that comparing to silicon,titanium can be preferentially reduced by one-step electron transfer due to the enhanced depolarization effect on a liquid copper cathode.So,Ti-Cu alloys are firstly obtained from molten Ti-bearing slag,and then Ti-Si alloys are co-electrodeposited in the molten oxide electrolyte with low TiO2 content.It may be ascribed to the larger binding force between titanium and copper than that between silicon and copper.It provides an effective strategy for the separation of titanium from of Ti-bearing slag.展开更多
Dexmedetomidine is a selective α2-adrenoceptor agonist that is used because of its sedative,anxiolytic,and analgesic effects.Dexketoprofen,which is used as an analgesic,is a nonselective nonsteroidal anti-inflammator...Dexmedetomidine is a selective α2-adrenoceptor agonist that is used because of its sedative,anxiolytic,and analgesic effects.Dexketoprofen,which is used as an analgesic,is a nonselective nonsteroidal anti-inflammatory drug (NSAID).The use of dexmedetomidine and dexketoprofen as adjuvants to local anesthetics for the peripheral nerve is gradually increasing.In this study,we aimed to investigate the effects of different doses of dexmedetomidine and dexketoprofen on conduction block of rat sciatic nerve.The isolated sciatic nerve from adult rats was transferred to a nerve chamber.The compound action potentials (CAPs) were recorded from stimulated nerve with electrophysiological methods.Dexmedetomidine (n = 8) and dexketoprofen (n = 8) were administered in the chamber with cumulative concentrations of 10–9 to 10–5 M,and the CAPs were recorded for 5 and 10 minutes.The CAP parameters were calculated.Both dexmedetomidine and dexketoprofen significantly depressed all CAP parameters in a dose-dependent manner compared with the control group,i.e.,the group in which rats did not receive treatment.CAP parameters showed there was no significant difference in nerve conduction inhibition between dexmedetomidine and dexketoprofen.Higher doses of dexmedetomidine suppressed the conduction in the fast-conducting fibers;however,dexketoprofen was found to suppress the conduction in the slow-conducting fibers in a time-dependent manner and suppress the conduction in the medium- and slow-conducting fibers in a dose-dependent manner.These findings suggest that dexmedetomidine and dexketoprofen exhibit better anesthetic effects on peripheral nerve through different ways of action.The experimental procedures were approved by the Necmettin Erbakan University on January 30,2013 (approval No.2013-024).展开更多
Brugada syndrome is a primary electrical disorder of theheart, predisposing affected individuals to potentially lethal,ventricular tachy-arrhythmias. A number of mechanismshave been identified as being important incre...Brugada syndrome is a primary electrical disorder of theheart, predisposing affected individuals to potentially lethal,ventricular tachy-arrhythmias. A number of mechanismshave been identified as being important increasing the riskof these rhythms. Wavelength (γ) restitution has beensuggested to predict the onset of action potential duration(APD) alternans in mouse Scn5a^+/- hearts modelling Bru-gada syndrome.展开更多
Sm extraction from a LiCl-KCl melt was carried out by forming alloys on various electrodes,including Al,Ni,Cu,and liquid Zn,and the electrochemical behaviors of the resultant metal products were investigated using dif...Sm extraction from a LiCl-KCl melt was carried out by forming alloys on various electrodes,including Al,Ni,Cu,and liquid Zn,and the electrochemical behaviors of the resultant metal products were investigated using different electrochemical techniques.While Sm metal deposition via the conventional two-step reaction process was not noted on the inert electrode,underpotential deposition was observed on the reactive electrodes because of the latter's depolarization effect.The depolarization effects of the reactive electrodes on Sm showed the order Zn>Al>Ni>Cu.Sm-M(M=Al,Ni,Cu,Zn)alloys were deposited by galvanostatic and potentiostatic electrolysis.The products were fully characterized by X-ray diffractometry(XRD)and scanning electron microscopy(SEM)-energy dispersive spectrometry(EDS),and the stability of the obtained M-rich compounds was determined.Finally,the relationship between the electrode potential and type of Sm-M intermetallic compounds formed was assessed on the basis of the observed electrochemical properties and electrodeposits.展开更多
Sodium-potassium-chloride cotransporter 1 (NKCC1) and potassium-chloride cotransporter 2 (KCC2) are associated with the transmission of peripheral pain.We investigated whether the increase of NKCC1 and KCC2 is associa...Sodium-potassium-chloride cotransporter 1 (NKCC1) and potassium-chloride cotransporter 2 (KCC2) are associated with the transmission of peripheral pain.We investigated whether the increase of NKCC1 and KCC2 is associated with peripheral pain transmission in dorsal root ganglion neurons.To this aim,rats with persistent hyperalgesia were randomly divided into four groups.Rats in the control group received no treatment,and the rat sciatic nerve was only exposed in the sham group.Rats in the chronic constriction injury group were established into chronic constriction injury models by ligating sciatic nerve and rats were given bumetanide,an inhibitor of NKCC1,based on chronic constriction injury modeling in the chronic constriction injury + bumetanide group.In the experiment measuring thermal withdrawal latency,bumetanide (15 mg/kg) was intravenously administered.In the patch clamp experiment,bumetanide (10 μg/μL) and acutely isolated dorsal root ganglion neurons (on day 14) were incubated for 1 hour,or bumetanide (5 μg/μL) was intrathecally injected.The Hargreaves test was conducted to detect changes in thermal hyperalgesia in rats.We found that the thermal withdrawal latency of rats was significantly decreased on days 7,14,and 21 after model establishment.After intravenous injection of bumetanide,the reduction in thermal retraction latency caused by model establishment was significantly inhibited.Immunohistochemistry and western blot assay results revealed that the immune response and protein expression of NKCC1 in dorsal root ganglion neurons of the chronic constriction injury group increased significantly on days 7,14,and 21 after model establishment.No immune response or protein expression of KCC2 was observed in dorsal root ganglion neurons before and after model establishment.The Cl^– (chloride ion) fluorescent probe technique was used to evaluate the change of Cl^– concentration in dorsal root ganglion neurons of chronic constriction injury model rats.We found that the relative optical density of N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (a Cl^– fluorescent probe whose fluorescence Cenintensity decreases as Cl– concentration increases) in the dorsal root ganglion neurons of the chronic constriction injury group was significantly decreased on days 7 and 14 after model establishment.The whole-cell patch clamp technique revealed that the resting potential and action potential frequency of dorsal root ganglion neurons increased,and the threshold and rheobase of action potentials decreased in the chronic constriction injury group on day 14 after model establishment.After bumetanide administration,the above indicators were significantly suppressed.These results confirm that CCI can induce abnormal overexpression of NKCC1,thereby increasing the Cl^– concentration in dorsal root ganglion neurons;this then enhances the excitability of dorsal root ganglion neurons and ultimately promotes hyperalgesia and allodynia.In addition,bumetanide can achieve analgesic effects.All experiments were approved by the Institutional Ethics Review Board at the First Affiliated Hospital,College of Medicine,Shihezi University,China on February 22,2017 (approval No.A2017-169-01).展开更多
The earth-abundant magnesium metal is a kind of promising anode material due to its low reduction potential (-2.356V vs. SHE), high volumetric and gravimetric specific capacities of 3882 mAh cm-3 and 2234 mAh g_1 resp...The earth-abundant magnesium metal is a kind of promising anode material due to its low reduction potential (-2.356V vs. SHE), high volumetric and gravimetric specific capacities of 3882 mAh cm-3 and 2234 mAh g_1 respectively [1]. Moreover, the magnesium anode shows high safety due to the non-dentritic electrodeposition mechanism during cycling, which is related to the strong Mg-Mg bonding and the consequent high energy barrier between the crystal boundaries of different crystal orientation [2].展开更多
Intracellular recording method of electrophysiology was used to study the effect of microinjection of coriaria lactone (CL) into hippocampus on membrane potential of hippocampal neurons in rats. The membrane potential...Intracellular recording method of electrophysiology was used to study the effect of microinjection of coriaria lactone (CL) into hippocampus on membrane potential of hippocampal neurons in rats. The membrane potential in 34 neurons of 12 rats were recorded. The results showed that CL induced depolarization of all of 34 neurons examined. Among the 34 neurons, 15 had paroxysmal depolarization accompanied by spike discharge in cluster and spike discharge in cluster ceased when membrane was hyperpolarized, 7 showed continuous depolarization accompanied by continuous spike discharge and 12 had only depolarizing response. The results suggest that injection of CL into hippocampus may lead to an increase of excitability of local neurons accompanied by different patterns of epileptioform discharge.展开更多
We present a systematic investigation of the depolarization properties of a supercontinuum accompanied with femtosecond laser filamentation in barium fluoride(BaF2)crystal.It is found that the depolarization of the su...We present a systematic investigation of the depolarization properties of a supercontinuum accompanied with femtosecond laser filamentation in barium fluoride(BaF2)crystal.It is found that the depolarization of the supercontinuum depends strongly on the crystal orientations with respect to the incident laser polarization.At most crystal orientations,the depolarization of the supercontinuum rises with the increase of the input laser energies and finally saturates.While at 45°,the depolarization of the supercontinuum is not changed and keeps nearly negligible with the increase of the input laser energies.These peculiar depolarization properties of the supercontinuum can be ascribed to the orientation dependence of the cross-polarized wave(XPW)generation and ionization-induced plasma scattering in the BaF2 crystal.展开更多
Scattering of the electromagnetic waves by a randomly inhomogeneous electrically gyrotropic slab are studied using the perturbation method. Second order statistical moments of the ordinary and extraordinary waves scat...Scattering of the electromagnetic waves by a randomly inhomogeneous electrically gyrotropic slab are studied using the perturbation method. Second order statistical moments of the ordinary and extraordinary waves scattered by the magnetized plasma slab are obtained using the boundary conditions for an arbitrary correlation function of electron density fluctuations. Normalized correlation functions at quasi-longitudinal propagation along the external magnetic field are calculated for the carrier frequency 0.1 MHz and 40 MHz. Isolines of the normalized variance of Faraday angle are constructed for the anisotropic Gaussian correlation function at various anisotropy factors of irregularities. Obtained results are in a good agreement with the experimental data.展开更多
Depending on various government policies,COVID-19(Corona Virus Disease-19) lockdowns have had diverse impacts on global aerosol concentrations.In 2022,Changchun a provincial capital city in Northeast China,suffered a ...Depending on various government policies,COVID-19(Corona Virus Disease-19) lockdowns have had diverse impacts on global aerosol concentrations.In 2022,Changchun a provincial capital city in Northeast China,suffered a severe COVID-19 outbreak and implemented a very strict lockdown that lasted for nearly two months.Using ground-based polarization Light Detection and Ranging(LiDAR),we detected real-time aerosol profile parameters(EC,extinction coefficient;DR,depolarization ratio;AOD,aerosol optical depth),as well as air-quality and meteorological indexes from 1 March to 30 April in 2021 and 2022 to quantify the effects of lockdown on aerosol concentrations.The period in 2022 was divided into three stages:pre-lockdown(1-10 March),strict lockdown(11 March to 10 April),and partial lockdown(11-30 April).The results showed that,during the strict lockdown period,compared with the pre-lockdown period,there were substantial reductions in aerosol parameters(EC and AOD),and this was consistent with the concentrations of the atmospheric pollutants PM_(2.5)(particulate matter with an aerodynamic diameter ≤2.5 μm) and PM_(2.5)(particulate matter with an aerodynamic diameter ≤10 μm),and the Oconcentration increased by 8.3%.During the strict lockdown,the values of EC within0-1 km and AOD decreased by 16.0% and 11.2%,respectively,as compared to the corresponding period in 2021.Lockdown reduced the conventional and organized emissions of air pollutants,and it clearly delayed the time of seasonal emissions from agricultural burning;however,it did not decrease the number of farmland fire points.Considering meteorological factors and eliminating the influence of wind-blown dust events,the results showed that reductions from conventional organized emission sources during the strict lockdown contributed to a 30% air-quality improvement and a 22% reduction in near-surface extinction(0-2 km).Aerosols produced by urban epidemic prevention and disinfection can also be identified using the EC.Regarding seasonal sources of agricultural straw burning,the concentrated burning induced by the epidemic led to the occurrence of heavy pollution from increased amounts of atmospheric aerosols,with a contribution rate of 62%.These results indicate that there is great potential to further improve air quality in the local area,and suggest that the comprehensive use of straw accompanied by reasonable planned burning is the best way to achieve this.展开更多
TNNI3K is a cardiac-specific and cardiac troponin I(cT n I)-interacting MAP kinase, known to play important roles in promoting cardiac differentiation, maintenance of beating rhythm and contractual force. The molecula...TNNI3K is a cardiac-specific and cardiac troponin I(cT n I)-interacting MAP kinase, known to play important roles in promoting cardiac differentiation, maintenance of beating rhythm and contractual force. The molecular structure of TNNI3 K contains three kinds of domain: a seven or ten NH2-terminal ankyrin repeat domain followed by a protein kinase domain and a COOH-terminal serine-rich domain. There are many binding sites in the structure of TNNI3 K for binding to ATP, magnesium, nucleotide, protein kinase C, antioxidant protein 1(AOP-1) and cT n I, indicating TNNI3 K has many interacting partners. This review summarizes the evidence, hypothesis and significance of TNNI3 K interacting with TNNI3 and its other putative interaction partners. From the literature, the interaction partners of TNNI3 K are divided into 2 types following their phenotypic pattern of functions, positive interaction(to increase the cardiac performance) or negative interaction(to suppress the cardiac performance). Following their binding sites, it also can be divided into other 2 types: binding to C-terminal domain(e.g., cT n I) or binding to both ankyrin repeat domain and C-terminal domains(AOP-1).To date, a well understood partner of TNNI3 K is cT nI, from the molecular structure, physiological function, mechanisms and its significance in some physiological and pathophysiological conditions. There are many reasons to believe that, with more understanding on the TNNI3 K interacting with its partners, we can understand more roles of TNNI3 K in some cardiac diseases.展开更多
Objective To study the role of early afterdepolarizations(EAD) in producing a trigger to initiate Torsade de pointes(Tdp) with QT prolongation induced by D sotalol,and to examine the contribution of transmural dispers...Objective To study the role of early afterdepolarizations(EAD) in producing a trigger to initiate Torsade de pointes(Tdp) with QT prolongation induced by D sotalol,and to examine the contribution of transmural dispersion of repolarization(TDR) to transmural propagation of EAD and maintenance of Tdp. Methods Transmembrane action potentials from epicardium and endocardium were recorded simultaneously by using floating glass microelectrode,together with a transmural ECG,in arterially perfused rabbit left ventricular preparations.The role of D sotalol on action potential duration(APD) of different layer myocytes,TDR,EAD,R on T extrasystole and polymorphous ventricular tachycardia(PMVT) were observed. Results In arterially perfused rabbit left ventricular wedge preparations,D sotalol(100 umol·L -1 ) preferentially prolong APD of endo myocytes,leading to QT interval prolongation and an increase of TDR.The incidence of EAD,R on T premature beats and spontaneous Tdp are 7/7,7/7 and 3/7( P <0.05) respectively. Conclusion Using an LQT2 model in arterially perfused rabbit left ventricular wedge preparations,we find that in intact ventricular wall,EAD can be generated and a trigger to initiate the onset of Tdp can be produced.Increasing TDR not only facilitates transmural propagation of EAD but also contribute to the maintenance of Tdp.展开更多
The [001]c-polarized(1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMN-PT) single crystals are widely used in ultrasonic detection transducers and underwater acoustic sensors. However, the relatively small coercive field( 2 kV/cm) of...The [001]c-polarized(1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMN-PT) single crystals are widely used in ultrasonic detection transducers and underwater acoustic sensors. However, the relatively small coercive field( 2 kV/cm) of such crystals restricts their application at high frequencies because the driving field will exceed the coercive field. The depolarization field can be considerably larger in an antiparallel direction than in a parallel direction with respect to polarization when the bipolar driving cycle starts. Thus, if the direction of the sine wave signal in the first half cycle is opposite to the polarization direction, then the depolarized domains can be repolarized in the second half of the sine cycle. However, if the direction of the sine wave signal in the first half of the cycle is along the polarization direction, then the change is negligible,and the domains switched in the second half of the sine cycle cannot be recovered. The design of electric driving method needs to allow the use of a large applied field to emit strong enough signals and produce good images. This phenomenon combined with the coercive field increases with the driving frequency, thereby making the PMN-PT single crystals usable for high-frequency applications. As such, the applied field can be considerably larger than the conventionally defined coercive field.展开更多
基金supported by the National Key R&D Program of China,No.2020YFC2008302the National Natural Science Foundation of China,No.81673631the Science and Technology Program of Sichuan Province,No.2020YFH0059 (all to YL)。
文摘Gabapentinoid drugs(pregabalin and gabapentin) have been successfully used in the treatment of neuro pathic pain and in focal seizure prevention.Recent research has demonstrated their potent activities in modulating neurotransmitter release in neuronal tissue,oxidative stress,and inflammation,which matches the mechanism of action via voltage-gated calcium channels.In this review,we briefly elaborate on the medicinal history and ligand-binding sites of gabapentinoids.We systematically summarize the preclinical and clinical research on gabapentinoids in stroke,including ischemic stro ke,intracerebral hemorrhage,subarachnoid hemorrhage,seizures after stro ke,cortical spreading depolarization after stroke,pain after stroke,and nerve regeneration after stro ke.This review also discusses the potential to rgets of gabapentinoids in stroke;however,the existing results are still unce rtain regarding the effect of gabapentinoids on stroke and related diseases.Further preclinical and clinical trials are needed to test the therapeutic potential of gabapentinoids in stroke.Therefore,gabapentinoids have both opportunities and challenges in the treatment of stroke.
基金funded by the National Research Developm ent and Innovation Office (NKFIH-K1468 73) (to BP)。
文摘Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of astrocytes.These events are significantly slower than the excitatory postsynaptic currents.Parameters of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto rs.Astrocytes are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback loop.Mostly as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological conditions.There is a growing body of evidence on the roles of slow inward currents on a single neuron or local network level.These events often occur in synchro ny on neurons located in the same astrocytic domain.Besides synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic plasticity.In addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory inputs.Of note,there might be important regionspecific differences in the roles and actions triggering slow inward currents.In greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological ones.Slow inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural networks.Slow inward currents are significant contributors to paroxysmal depolarizational shifts/interictal spikes.These events are related to epilepsy,but also found in Alzheimer's disease,Parkinson's disease,and stroke,leading to the decline of cognitive functions.Events with features overlapping with slow inward currents(excitatory,N-methyl-Daspartate-receptor mediated currents with astrocytic contribution) as ischemic currents and spreading depolarization also have a well-known pathophysiological role in worsening consequences of stroke,traumatic brain injury,or epilepsy.One might assume that slow inward currents occurring with low frequency under physiological conditions might contribute to synaptic plasticity and memory formation.However,to state this,more experimental evidence from greater neuronal networks or the level of the individual is needed.In this review,I aimed to summarize findings on slow inward currents and to speculate on the potential functions of it.
基金supported by University of Florence RICATEN 2023 to EC.Grant/Award Numbers 58514_InternazionalizzazioneUniversity of Florence,to EC.Parkinson’s UK,Grant/Award Number:H-0902 to AJGWellcome Trust,Grant/Award Number:0926/Z/10/Z to AJG。
文摘During brain ischemia,excitotoxicity and peri-infarct depolarization injuries occur and cause cerebral tissue damage.Indeed,anoxic depolarization,consisting of massive neuronal depolarization due to the loss of membrane ion gradients,occurs in vivo or in vitro during an energy failure.The neuromodulator adenosine is released in huge amounts during cerebral ischemia and exerts its effects by activating specific metabotropic receptors,namely:A_(1),A_(2A),A_(2B),and A_(3).The A_(2A)receptor subtype is highly expressed in striatal medium spiny neurons,which are particularly susceptible to ischemic damage.Evidence indicates that the A2Areceptors are upregulated in the rat striatum after stroke and the selective antagonist SCH58261 protects from exaggerated glutamate release within the first 4 hours from the insult and alleviates neurological impairment and histological injury in the following 24 hours.We recently added new knowledge to the mechanisms by which the adenosine A2Areceptor subtype participates in ischemia-induced neuronal death by performing patch-clamp recordings from medium spiny neurons in rat striatal brain slices exposed to oxygen and glucose deprivation.We demonstrated that the selective block of A2Areceptors by SCH58261 significantly reduced ionic imbalance and delayed the anoxic depolarization in medium spiny neurons during oxygen and glucose deprivation and that the mechanism involves voltage-gated K+channel modulation and a presynaptic inhibition of glutamate release by the A2Areceptor antagonist.The present review summarizes the latest findings in the literature about the possibility of developing selective ligands of A2Areceptors as advantageous therapeutic tools that may contribute to counteracting neurodegeneration after brain ischemia.
基金supported by the Guang Dong Basic and Applied Basic Research Foundation,China(2021B1515120025)。
文摘Ultraviolet(UV)photodetectors are extensively adopted in the fields of the Internet of Things,optical communications and imaging.Nowadays,with broadening the application scope of UV photodetectors,developing integrated devices with more functionalities rather than basic photo-detecting ability are highly required and have been triggered ever-growing interest in scientific and industrial communities.Ferroelectric thin films have become a potential candidate in the field of UV detection due to their wide bandgap and unique photovoltaic characteristics.Additionally,ferroelectric thin films perform excellent dielectric,piezoelectric,pyroelectric,acousto-optic effects,etc.,which can satisfy the demand for the diversified development of UV detectors.In this review,according to the different roles of ferroelectric thin films in the device,the UV photodetectors based on ferroelectric films are classified into ferroelectric depolarization field driven type,ferroelectric depolarization field and built-in electric field co-driven type,and ferroelectric field enhanced type.These three types of ferroelectric UV photodetectors have great potential and are expected to promote the development of a new generation of UV detection technology.At the end of the paper,the advantages and challenges of three types of ferroelectric UV photodetectors are summarized,and the possible development direction in the future is proposed.
基金This work was supported by the National Key Projects for Fundamental Research, "Macromolecular Condensed State" of Ministry of Science and Technology of China.
文摘The kinetics of I→N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.
基金National Natural Science Foundation of China(913322028122100381603084).
文摘Temporal lobe epilepsy(TLE) is a common type of epilepsy and is not well controlled by current treatments.The frequent failure to treat TLE may be due to our lack of precise cellular/circuit mechanisms underlying TLE.The early series of our studies have proved the success of low-frequency stimulation treatment for epilepsy,which was mainly depending on the stimulation target,the stimulation frequency and stimulation time(the therapeutic-window phenomenon).Now,by using optogenetics,viral tracing,multiple-channel EEG analysis,imaging,electrophysiology and pharmacology strategies,we are continued to investigate the circuit mechanism of therapeutic deep brain stimulation,and found that entorhinal principal neurons mediate antiepileptic ″ glutamatergic-GABAergic″ neuronal circuit for brain stimulation treatments of epilepsy.Meanwhile,we are currently focusing on the interplay of inhibitory and excitatory network in the key input/output regions of the hippocampus that related to the generation of in TLE.Specially,we found that depolarized GABAergic signaling in subicular microcircuit mediates generalized seizures in TLE and a direct septal cholinergic circuit attenuates TLE through driving hippocampal somatostatin inhibition.These findings may be of therapeutic interest in understanding the pathological neuronal circuitry in TLE and further the development of novel therapeutic approaches or drug targets.
基金This project was supported by a grant from EducationalMinistry Foundation of China (No.[2 0 0 1]34 5 )
文摘Whether the ATP sensitive potassium channel opener pinacidil can provide myocardial protective effects in prolonged isolated global ischemic rat heart was investigated. On modified isolated rat working heart model, 40 hearts were divided into four groups randomly: Hyperpolarized arrest H K solution containing pinacidil (50 μmol/L) (P1 and P2) and depolarized arrest St. Thomas’ solution (S1 and S2) subjected to 15 ℃ hypothermia, 60 min (P1 and S1) or 120 min (P1 and S2) of ischemia and 30 min reperfusion. The experimental indices included cardioplegic efficiency, cardiac function, coronary blood flow, myocardial enzyme release, myocardial water and ATP content. Hyperpolarized arrest provided significantly better recovery of cardiac function than depolarized arrest. Postischemic coronary flow and myocardial ATP content were higher. The arrest time of electro mechanical activities were longer than depolarized arrest. There were no differences among the groups in myocardial water contents. The hyperpolarized arrest solution containing pinacidil can provide a marked myocardial protective effect during prolonged hypothermic myocardial ischemia.
基金supported by the National Natural Science Foundation of China(51725401)the Fundamental Research Funds for the Central Universities(FRF-TP-18-010B1).
文摘Ti-bearing slag(TiO2>20 wt%)is a valuable titanium secondary resource.The extraction of titanium from the slag is difficult due to the complex composition and structure.Although molten oxide electrolysis is considered as a promising method,silicon will be preferentially electroreduced compared to titanium due to low theoretical decomposition voltage.In this work,a liquid copper cathode is used to selectively extract titanium from molten Al2O3-MgO-CaO-TiO2-SiO2 electrolyte.It is found that comparing to silicon,titanium can be preferentially reduced by one-step electron transfer due to the enhanced depolarization effect on a liquid copper cathode.So,Ti-Cu alloys are firstly obtained from molten Ti-bearing slag,and then Ti-Si alloys are co-electrodeposited in the molten oxide electrolyte with low TiO2 content.It may be ascribed to the larger binding force between titanium and copper than that between silicon and copper.It provides an effective strategy for the separation of titanium from of Ti-bearing slag.
基金Scientific Committee Foundation(No.13102007) of Selcuk University,Konya,Turkey(to HB)
文摘Dexmedetomidine is a selective α2-adrenoceptor agonist that is used because of its sedative,anxiolytic,and analgesic effects.Dexketoprofen,which is used as an analgesic,is a nonselective nonsteroidal anti-inflammatory drug (NSAID).The use of dexmedetomidine and dexketoprofen as adjuvants to local anesthetics for the peripheral nerve is gradually increasing.In this study,we aimed to investigate the effects of different doses of dexmedetomidine and dexketoprofen on conduction block of rat sciatic nerve.The isolated sciatic nerve from adult rats was transferred to a nerve chamber.The compound action potentials (CAPs) were recorded from stimulated nerve with electrophysiological methods.Dexmedetomidine (n = 8) and dexketoprofen (n = 8) were administered in the chamber with cumulative concentrations of 10–9 to 10–5 M,and the CAPs were recorded for 5 and 10 minutes.The CAP parameters were calculated.Both dexmedetomidine and dexketoprofen significantly depressed all CAP parameters in a dose-dependent manner compared with the control group,i.e.,the group in which rats did not receive treatment.CAP parameters showed there was no significant difference in nerve conduction inhibition between dexmedetomidine and dexketoprofen.Higher doses of dexmedetomidine suppressed the conduction in the fast-conducting fibers;however,dexketoprofen was found to suppress the conduction in the slow-conducting fibers in a time-dependent manner and suppress the conduction in the medium- and slow-conducting fibers in a dose-dependent manner.These findings suggest that dexmedetomidine and dexketoprofen exhibit better anesthetic effects on peripheral nerve through different ways of action.The experimental procedures were approved by the Necmettin Erbakan University on January 30,2013 (approval No.2013-024).
文摘Brugada syndrome is a primary electrical disorder of theheart, predisposing affected individuals to potentially lethal,ventricular tachy-arrhythmias. A number of mechanismshave been identified as being important increasing the riskof these rhythms. Wavelength (γ) restitution has beensuggested to predict the onset of action potential duration(APD) alternans in mouse Scn5a^+/- hearts modelling Bru-gada syndrome.
基金the National Natural Science Foundation of China(Nos.21976047,21790373,and 51774104)the Ph.D.Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities,China(No.3072019GIP1011)the Fundamental Research Funds for the Central Universities,China(No.3072020CFT1008)。
文摘Sm extraction from a LiCl-KCl melt was carried out by forming alloys on various electrodes,including Al,Ni,Cu,and liquid Zn,and the electrochemical behaviors of the resultant metal products were investigated using different electrochemical techniques.While Sm metal deposition via the conventional two-step reaction process was not noted on the inert electrode,underpotential deposition was observed on the reactive electrodes because of the latter's depolarization effect.The depolarization effects of the reactive electrodes on Sm showed the order Zn>Al>Ni>Cu.Sm-M(M=Al,Ni,Cu,Zn)alloys were deposited by galvanostatic and potentiostatic electrolysis.The products were fully characterized by X-ray diffractometry(XRD)and scanning electron microscopy(SEM)-energy dispersive spectrometry(EDS),and the stability of the obtained M-rich compounds was determined.Finally,the relationship between the electrode potential and type of Sm-M intermetallic compounds formed was assessed on the basis of the observed electrochemical properties and electrodeposits.
基金supported by the National Natural Science Foundation of China,No.30160026(to JQS)the High Level Talent Research Project of Shihezi University of China,No.RCSX201705(to YW)
文摘Sodium-potassium-chloride cotransporter 1 (NKCC1) and potassium-chloride cotransporter 2 (KCC2) are associated with the transmission of peripheral pain.We investigated whether the increase of NKCC1 and KCC2 is associated with peripheral pain transmission in dorsal root ganglion neurons.To this aim,rats with persistent hyperalgesia were randomly divided into four groups.Rats in the control group received no treatment,and the rat sciatic nerve was only exposed in the sham group.Rats in the chronic constriction injury group were established into chronic constriction injury models by ligating sciatic nerve and rats were given bumetanide,an inhibitor of NKCC1,based on chronic constriction injury modeling in the chronic constriction injury + bumetanide group.In the experiment measuring thermal withdrawal latency,bumetanide (15 mg/kg) was intravenously administered.In the patch clamp experiment,bumetanide (10 μg/μL) and acutely isolated dorsal root ganglion neurons (on day 14) were incubated for 1 hour,or bumetanide (5 μg/μL) was intrathecally injected.The Hargreaves test was conducted to detect changes in thermal hyperalgesia in rats.We found that the thermal withdrawal latency of rats was significantly decreased on days 7,14,and 21 after model establishment.After intravenous injection of bumetanide,the reduction in thermal retraction latency caused by model establishment was significantly inhibited.Immunohistochemistry and western blot assay results revealed that the immune response and protein expression of NKCC1 in dorsal root ganglion neurons of the chronic constriction injury group increased significantly on days 7,14,and 21 after model establishment.No immune response or protein expression of KCC2 was observed in dorsal root ganglion neurons before and after model establishment.The Cl^– (chloride ion) fluorescent probe technique was used to evaluate the change of Cl^– concentration in dorsal root ganglion neurons of chronic constriction injury model rats.We found that the relative optical density of N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (a Cl^– fluorescent probe whose fluorescence Cenintensity decreases as Cl– concentration increases) in the dorsal root ganglion neurons of the chronic constriction injury group was significantly decreased on days 7 and 14 after model establishment.The whole-cell patch clamp technique revealed that the resting potential and action potential frequency of dorsal root ganglion neurons increased,and the threshold and rheobase of action potentials decreased in the chronic constriction injury group on day 14 after model establishment.After bumetanide administration,the above indicators were significantly suppressed.These results confirm that CCI can induce abnormal overexpression of NKCC1,thereby increasing the Cl^– concentration in dorsal root ganglion neurons;this then enhances the excitability of dorsal root ganglion neurons and ultimately promotes hyperalgesia and allodynia.In addition,bumetanide can achieve analgesic effects.All experiments were approved by the Institutional Ethics Review Board at the First Affiliated Hospital,College of Medicine,Shihezi University,China on February 22,2017 (approval No.A2017-169-01).
基金supported by the National Natural Science Foundation of China (no. 51772068, 21773049)
文摘The earth-abundant magnesium metal is a kind of promising anode material due to its low reduction potential (-2.356V vs. SHE), high volumetric and gravimetric specific capacities of 3882 mAh cm-3 and 2234 mAh g_1 respectively [1]. Moreover, the magnesium anode shows high safety due to the non-dentritic electrodeposition mechanism during cycling, which is related to the strong Mg-Mg bonding and the consequent high energy barrier between the crystal boundaries of different crystal orientation [2].
基金a grant from the NationalNatural Science Foundation of China (No. 39330210).
文摘Intracellular recording method of electrophysiology was used to study the effect of microinjection of coriaria lactone (CL) into hippocampus on membrane potential of hippocampal neurons in rats. The membrane potential in 34 neurons of 12 rats were recorded. The results showed that CL induced depolarization of all of 34 neurons examined. Among the 34 neurons, 15 had paroxysmal depolarization accompanied by spike discharge in cluster and spike discharge in cluster ceased when membrane was hyperpolarized, 7 showed continuous depolarization accompanied by continuous spike discharge and 12 had only depolarizing response. The results suggest that injection of CL into hippocampus may lead to an increase of excitability of local neurons accompanied by different patterns of epileptioform discharge.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11527807,11674356,11834015,and 91850121)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21010400)the Open Fund of the State Key Laboratory of High Field Laser Physics,China
文摘We present a systematic investigation of the depolarization properties of a supercontinuum accompanied with femtosecond laser filamentation in barium fluoride(BaF2)crystal.It is found that the depolarization of the supercontinuum depends strongly on the crystal orientations with respect to the incident laser polarization.At most crystal orientations,the depolarization of the supercontinuum rises with the increase of the input laser energies and finally saturates.While at 45°,the depolarization of the supercontinuum is not changed and keeps nearly negligible with the increase of the input laser energies.These peculiar depolarization properties of the supercontinuum can be ascribed to the orientation dependence of the cross-polarized wave(XPW)generation and ionization-induced plasma scattering in the BaF2 crystal.
文摘Scattering of the electromagnetic waves by a randomly inhomogeneous electrically gyrotropic slab are studied using the perturbation method. Second order statistical moments of the ordinary and extraordinary waves scattered by the magnetized plasma slab are obtained using the boundary conditions for an arbitrary correlation function of electron density fluctuations. Normalized correlation functions at quasi-longitudinal propagation along the external magnetic field are calculated for the carrier frequency 0.1 MHz and 40 MHz. Isolines of the normalized variance of Faraday angle are constructed for the anisotropic Gaussian correlation function at various anisotropy factors of irregularities. Obtained results are in a good agreement with the experimental data.
基金the Key Research Program of Frontier Sciences,Chinese Academy of Sciences (No. QYZDB-SSW-DQC045)the National Natural Science Foundation of China (No. 41775116)。
文摘Depending on various government policies,COVID-19(Corona Virus Disease-19) lockdowns have had diverse impacts on global aerosol concentrations.In 2022,Changchun a provincial capital city in Northeast China,suffered a severe COVID-19 outbreak and implemented a very strict lockdown that lasted for nearly two months.Using ground-based polarization Light Detection and Ranging(LiDAR),we detected real-time aerosol profile parameters(EC,extinction coefficient;DR,depolarization ratio;AOD,aerosol optical depth),as well as air-quality and meteorological indexes from 1 March to 30 April in 2021 and 2022 to quantify the effects of lockdown on aerosol concentrations.The period in 2022 was divided into three stages:pre-lockdown(1-10 March),strict lockdown(11 March to 10 April),and partial lockdown(11-30 April).The results showed that,during the strict lockdown period,compared with the pre-lockdown period,there were substantial reductions in aerosol parameters(EC and AOD),and this was consistent with the concentrations of the atmospheric pollutants PM_(2.5)(particulate matter with an aerodynamic diameter ≤2.5 μm) and PM_(2.5)(particulate matter with an aerodynamic diameter ≤10 μm),and the Oconcentration increased by 8.3%.During the strict lockdown,the values of EC within0-1 km and AOD decreased by 16.0% and 11.2%,respectively,as compared to the corresponding period in 2021.Lockdown reduced the conventional and organized emissions of air pollutants,and it clearly delayed the time of seasonal emissions from agricultural burning;however,it did not decrease the number of farmland fire points.Considering meteorological factors and eliminating the influence of wind-blown dust events,the results showed that reductions from conventional organized emission sources during the strict lockdown contributed to a 30% air-quality improvement and a 22% reduction in near-surface extinction(0-2 km).Aerosols produced by urban epidemic prevention and disinfection can also be identified using the EC.Regarding seasonal sources of agricultural straw burning,the concentrated burning induced by the epidemic led to the occurrence of heavy pollution from increased amounts of atmospheric aerosols,with a contribution rate of 62%.These results indicate that there is great potential to further improve air quality in the local area,and suggest that the comprehensive use of straw accompanied by reasonable planned burning is the best way to achieve this.
文摘TNNI3K is a cardiac-specific and cardiac troponin I(cT n I)-interacting MAP kinase, known to play important roles in promoting cardiac differentiation, maintenance of beating rhythm and contractual force. The molecular structure of TNNI3 K contains three kinds of domain: a seven or ten NH2-terminal ankyrin repeat domain followed by a protein kinase domain and a COOH-terminal serine-rich domain. There are many binding sites in the structure of TNNI3 K for binding to ATP, magnesium, nucleotide, protein kinase C, antioxidant protein 1(AOP-1) and cT n I, indicating TNNI3 K has many interacting partners. This review summarizes the evidence, hypothesis and significance of TNNI3 K interacting with TNNI3 and its other putative interaction partners. From the literature, the interaction partners of TNNI3 K are divided into 2 types following their phenotypic pattern of functions, positive interaction(to increase the cardiac performance) or negative interaction(to suppress the cardiac performance). Following their binding sites, it also can be divided into other 2 types: binding to C-terminal domain(e.g., cT n I) or binding to both ankyrin repeat domain and C-terminal domains(AOP-1).To date, a well understood partner of TNNI3 K is cT nI, from the molecular structure, physiological function, mechanisms and its significance in some physiological and pathophysiological conditions. There are many reasons to believe that, with more understanding on the TNNI3 K interacting with its partners, we can understand more roles of TNNI3 K in some cardiac diseases.
文摘Objective To study the role of early afterdepolarizations(EAD) in producing a trigger to initiate Torsade de pointes(Tdp) with QT prolongation induced by D sotalol,and to examine the contribution of transmural dispersion of repolarization(TDR) to transmural propagation of EAD and maintenance of Tdp. Methods Transmembrane action potentials from epicardium and endocardium were recorded simultaneously by using floating glass microelectrode,together with a transmural ECG,in arterially perfused rabbit left ventricular preparations.The role of D sotalol on action potential duration(APD) of different layer myocytes,TDR,EAD,R on T extrasystole and polymorphous ventricular tachycardia(PMVT) were observed. Results In arterially perfused rabbit left ventricular wedge preparations,D sotalol(100 umol·L -1 ) preferentially prolong APD of endo myocytes,leading to QT interval prolongation and an increase of TDR.The incidence of EAD,R on T premature beats and spontaneous Tdp are 7/7,7/7 and 3/7( P <0.05) respectively. Conclusion Using an LQT2 model in arterially perfused rabbit left ventricular wedge preparations,we find that in intact ventricular wall,EAD can be generated and a trigger to initiate the onset of Tdp can be produced.Increasing TDR not only facilitates transmural propagation of EAD but also contribute to the maintenance of Tdp.
基金Project supported by the National Natural Science Foundation of China(Grant No.11674270)the Fundamental Research Funds for Xiamen University,China(Grant No.20720180113)+2 种基金the Education and Scientific Research Project for Young and Middle-aged Teachers of Fujian Province,China(Grant No.JAT170036)the Opening Fund of Acoustics Science and Technology Laboratory,China(Grant No.SSKF2018006)sponsored by the Education Department of Fujian Province,China for his study at the Pennsylvania State University(Grant No.2016071145)
文摘The [001]c-polarized(1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3(PMN-PT) single crystals are widely used in ultrasonic detection transducers and underwater acoustic sensors. However, the relatively small coercive field( 2 kV/cm) of such crystals restricts their application at high frequencies because the driving field will exceed the coercive field. The depolarization field can be considerably larger in an antiparallel direction than in a parallel direction with respect to polarization when the bipolar driving cycle starts. Thus, if the direction of the sine wave signal in the first half cycle is opposite to the polarization direction, then the depolarized domains can be repolarized in the second half of the sine cycle. However, if the direction of the sine wave signal in the first half of the cycle is along the polarization direction, then the change is negligible,and the domains switched in the second half of the sine cycle cannot be recovered. The design of electric driving method needs to allow the use of a large applied field to emit strong enough signals and produce good images. This phenomenon combined with the coercive field increases with the driving frequency, thereby making the PMN-PT single crystals usable for high-frequency applications. As such, the applied field can be considerably larger than the conventionally defined coercive field.