This study aimed to probe into occurrence and development of spontaneous firings in the telencephalon neurons of Hynobius leechi . [Method] Mi-croelectrode technique was used to record extracellular spontaneous electr...This study aimed to probe into occurrence and development of spontaneous firings in the telencephalon neurons of Hynobius leechi . [Method] Mi-croelectrode technique was used to record extracellular spontaneous electrical activi-ties of the telencephalon neurons of H. leechi in occurrence and development. [Re-sult] There were three discharge types in the occurrence of telencephalon in H. leechi , with single spontaneous firing and consecutive single spontaneous firing being main-ly apparent. And among the five types in the development of telencephalon, the main discharge type was single spontaneous firing. Along with the occurrence and development of telencephalon, the extracellular discharge intensity enhanced gradual-ly, the discharge duration increased, and the spontaneous firing frequency accelerat-ed, al of which reached the maximum in the adult phase. Fol owing the process of occurrence and development, other discharge types appeared successively. [Conclu-sion] Along with the occurrence and development of the telencephalon in H. leechi , the neuronal excitability increases step by step and the neuronal electrical activities diversify gradual y.展开更多
The response of synchronously firing groups of population retinal ganglion cells(RGCs)to natural movies(NMs)and pseudo-random white-noise checker-board flickering(CB,as control)are investigated using an information-th...The response of synchronously firing groups of population retinal ganglion cells(RGCs)to natural movies(NMs)and pseudo-random white-noise checker-board flickering(CB,as control)are investigated using an information-theoretic algorithm.The main results are:(1)the population RGCs tend to fire in synchrony far more frequently than expected by chance during both NM and CB stimulation;(2)more synchronous groups could be formed and each group contains more neurons under NM than CB stimulation;(3)the individual neurons also participate in more groups and have more distinct partners in NM than CB stimulation.All these results suggest that the synchronized firings in RGCs are more extensive and diverse,which may account for more effective information processing in representing the natural visual environment.展开更多
This study constructs a dual-capacitor neuron circuit(connected via a memristor)integrated with a phototube and a thermistor to simulate the ability of biological neurons to simultaneously perceive light and thermal s...This study constructs a dual-capacitor neuron circuit(connected via a memristor)integrated with a phototube and a thermistor to simulate the ability of biological neurons to simultaneously perceive light and thermal stimuli.The circuit model converts photothermal signals into electrical signals,and its dynamic behavior is described using dimensionless equations derived from Kirchhoff's laws.Based on Helmholtz's theorem,a pseudo-Hamiltonian energy function is introduced to characterize the system's energy metabolism.Furthermore,an adaptive control function is proposed to elucidate temperature-dependent firing mechanisms,in which temperature dynamics are regulated by pseudo-Hamiltonian energy.Numerical simulations using the fourth-order Runge-Kutta method,combined with bifurcation diagrams,Lyapunov exponent spectra,and phase portraits,reveal that parameters such as capacitance ratio,phototube voltage amplitude/frequency,temperature,and thermistor reference resistance significantly modulate neuronal firing patterns,inducing transitions between periodic and chaotic states.Periodic states typically exhibit higher average pseudo-Hamiltonian energy than chaotic states.Two-parameter analysis demonstrates that phototube voltage amplitude and temperature jointly govern firing modes,with chaotic behavior emerging within specific parameter ranges.Adaptive control studies show that gain/attenuation factors,energy thresholds,ceiling temperatures,and initial temperatures regulate the timing and magnitude of system temperature saturation.During both heating and cooling phases,temperature dynamics are tightly coupled with pseudoHamiltonian energy and neuronal firing activity.These findings validate the circuit's ability to simulate photothermal perception and adaptive temperature regulation,contributing to a deeper understanding of neuronal encoding mechanisms and multimodal sensory processing.展开更多
The human brain is a complex intelligent system composed of tens of billions of neurons interconnected through synapses,and its intricate network structure has consistently attracted numerous scientists to explore the...The human brain is a complex intelligent system composed of tens of billions of neurons interconnected through synapses,and its intricate network structure has consistently attracted numerous scientists to explore the mysteries of brain functions.However,most existing studies have only verified the biological mimicry characteristics of memristors at the single neuron-synapse level,and there is still a lack of research on memristors simulating synaptic coupling between neurons in multi-neuron networks.Based on this,this paper uses discrete memristors to couple dual discrete Rulkov neurons,and adds synaptic crosstalk between the two discrete memristors to form a neuronal network.A memristor-coupled dual-neuron map,called the Rulkov-memristor-Rulkov(R-M-R)map,is constructed to simulate synaptic connections between neurons in biological tissues.Then,the equilibrium points of the R-M-R map are studied.Subsequently,the effect of parameter variations on the dynamic performance of the R-M-R map is comprehensively analyzed using bifurcation diagram,phase diagram,Lyapunov exponent spectrum(LEs),firing diagram,and spectral entropy(SE)complexity algorithms.In the RM-R map,diverse categories of periodic,chaotic,and hyperchaotic attractors,as well as different states of firing patterns,can be observed.Additionally,different types of state transitions and coexisting attractors are discovered.Finally,the feasibility of the model in digital circuits is verified using a DSP hardware platform.In this study,the coupling principle of biological neurons is simulated,the chaotic dynamic behavior of the R-M-R map is analyzed,and a foundation is laid for deciphering the complex working mechanisms of the brain.展开更多
Transforming growth factor-beta 1(TGF-β1)has been extensively studied for its pleiotropic effects on central nervous system diseases.The neuroprotective or neurotoxic effects of TGF-β1 in specific brain areas may de...Transforming growth factor-beta 1(TGF-β1)has been extensively studied for its pleiotropic effects on central nervous system diseases.The neuroprotective or neurotoxic effects of TGF-β1 in specific brain areas may depend on the pathological process and cell types involved.Voltage-gated sodium channels(VGSCs)are essential ion channels for the generation of action potentials in neurons,and are involved in various neuroexcitation-related diseases.However,the effects of TGF-β1 on the functional properties of VGSCs and firing properties in cortical neurons remain unclear.In this study,we investigated the effects of TGF-β1 on VGSC function and firing properties in primary cortical neurons from mice.We found that TGF-β1 increased VGSC current density in a dose-and time-dependent manner,which was attributable to the upregulation of Nav1.3 expression.Increased VGSC current density and Nav1.3 expression were significantly abolished by preincubation with inhibitors of mitogen-activated protein kinase kinase(PD98059),p38 mitogen-activated protein kinase(SB203580),and Jun NH2-terminal kinase 1/2 inhibitor(SP600125).Interestingly,TGF-β1 significantly increased the firing threshold of action potentials but did not change their firing rate in cortical neurons.These findings suggest that TGF-β1 can increase Nav1.3 expression through activation of the ERK1/2-JNK-MAPK pathway,which leads to a decrease in the firing threshold of action potentials in cortical neurons under pathological conditions.Thus,this contributes to the occurrence and progression of neuroexcitatory-related diseases of the central nervous system.展开更多
Neural damage or degeneration is at the crux of many diseases,and treatment of these diseases will require the development of therapeutics to enhance and guide neural regeneration.Both intrinsic and extrinsic factors ...Neural damage or degeneration is at the crux of many diseases,and treatment of these diseases will require the development of therapeutics to enhance and guide neural regeneration.Both intrinsic and extrinsic factors dictate a neuron’s ability to regenerate,and the combination of these factors results in the great regenerative capacity of the peripheral nervous system(PNS)and the poor regenerative capacity of the central nervous system(CNS)following injury.At the core of a neuron’s function is its ability to relay electrochemical signals,and a neuron’s excitability is a key factor in its ability to regenerate.Recent works have focused on the changes in neuronal electrophysiological properties,firing patterns,and ion flux after injury,which differentially activate signaling pathways at the core of regeneration.The role of glia in neuron regeneration has long been studied.展开更多
LONGQUAN,a historic city in east China’s Zhejiang Province,is renowned for its exquisite celadon ware,featuring fine texture and pure,jade-like glaze.The region has a potterymaking tradition that spans over 1,600 yea...LONGQUAN,a historic city in east China’s Zhejiang Province,is renowned for its exquisite celadon ware,featuring fine texture and pure,jade-like glaze.The region has a potterymaking tradition that spans over 1,600 years.Its celadon firing technique originated during the Three Kingdoms Period(220-280)and reached its peak in the Southern Song Dynasty(1127-1279).Since the Song Dynasty(960-1368),Longquan was among the main suppliers of porcelain for the imperial court.From the 12th to the 15th centuries.展开更多
The interactions between fire,ecosystems,and climate are complex.Tropical ecosystems have dominated global active fires nowadays,yet its causes,mechanisms,and consequences remain relatively poorly understood.To in-ves...The interactions between fire,ecosystems,and climate are complex.Tropical ecosystems have dominated global active fires nowadays,yet its causes,mechanisms,and consequences remain relatively poorly understood.To in-vestigate temporal response of remotely-sensed active fires to intra-annual climate change,several 1-km datasets,including the Moderate-resolution Imaging Spectroradiometer Collection 6(MODIS C6)active fires and the Cli-matologies at High Resolution for the Earth’s Land Surface Areas(CHELSA)climate variables,were gathered to examine the climatic characteristics of active fire incidences,fire-climate correlations,and the average monthly response of active fire occurrences to climate change using the Geographic Information System(GIS)Fishnet tool,Theil-Sen Median slope estimation,Mann-Kendall significance test,and Pearson’s correlation.We concluded that climate variables’trends of nearly two-decade active fires displayed varied degrees of increment in precipitation(Pre),temperature(Tas),and surface downwelling shortwave radiation(Rsds)and inconsistent decrement in near-surface relative humidity(Hurs)and near-surface wind speed(sfcWind).MODIS multi-year(2003-2018)active fires were moderately to strongly correlated negatively with Pre and Hurs at 10 km grid-resolution but positively with sfcWind and Rsds,showing marked geographical variations in correlation direction and strength.The most significant finding is the newly observed inverse relationship between active fires and precipitation on both sides of the equator.High occurrence areas of active fires regularly appear back and forth along with latitudinal changes(at one-degree intervals)in monthly minimum precipitation between the tropical Northern and Southern Hemispheres.The present study contributes to exploring the underlying mechanism of fire-climate interactions against the backdrop of climate warming.展开更多
On 30 September 2024,the UK shuttered its last remaining coal-fired power plant[1].The closure marks a historic milestone,the end of 142 years of coal fueled prosperity.The country opened the world’s first plant to s...On 30 September 2024,the UK shuttered its last remaining coal-fired power plant[1].The closure marks a historic milestone,the end of 142 years of coal fueled prosperity.The country opened the world’s first plant to supply electric streetlamps in 1882,spark-ing a global energy revolution that has led to today’s nearly univer-sally electrified world.展开更多
Formaldehyde(HCHO)is a high-yield product of the oxidation of volatile organic compounds(VOCs)released by anthropogenic activities,fires,and vegetations.Hence,we examined the spatiotemporal variation trends in HCHO co...Formaldehyde(HCHO)is a high-yield product of the oxidation of volatile organic compounds(VOCs)released by anthropogenic activities,fires,and vegetations.Hence,we examined the spatiotemporal variation trends in HCHO columns observed using the Ozone Monitoring Instrument(OMI)during 2005–2021 across the Fenwei Plain(FWP)and analysed the source and variability of HCHO using multi-source data,such as thermal anomalies.The spatial distribution of the annualmean HCHO in the FWP increased from northwest to southeast during 2005–2021,and the high-value aggregation areas contracted and gradually clustered,forming a belt-shaped distribution area from Xi’an to Baoji,north of the Qinling Mountains.The annual mean HCHO concentration generally showed a two-step increase over the 17 years.Fires showed a single-peak trend in March and a double-peak M-shaped trend in March and October,whereas urban thermal anomalies(UTAs)showed an inverted U-shaped trend over 17 years,with peaks occurring in May.The HCHO peaks are mainly caused by the alternating contributions of fires and UTAs.The fires and UTAs(predominantly industrial heat sources)played a role in controlling the background level of HCHO in the FWP.Precipitation and temperature were also important influencing variables for seasonal variations,and the influence of plant sources on HCHO concentrations had significant regional characteristics and contributions.In addition,the FWP has poor dispersion conditions and is an aggregated area for the long-range transport of air pollutants.展开更多
Earthquakes can cause significant damage and loss of life,necessitating immediate assessment of the resulting fatalities.Rapid assessment and timely revision of fatality estimates are crucial for effective emergency d...Earthquakes can cause significant damage and loss of life,necessitating immediate assessment of the resulting fatalities.Rapid assessment and timely revision of fatality estimates are crucial for effective emergency decisionmaking.This study using the February 6,2023,M_(S)8.0 and M_(S)7.9 Kahramanmaras,Türkiye earthquakes as an example to estimate the ultimate number of fatalities.An early Quick Rough Estimate(QRE)based on the number of deaths reported by the Disaster and Emergency Management Presidency of Türkiye(AFAD)is conducted,and it dynamically adjusts these estimates as new data becomes available.The range of estimates of the final number of deaths can be calculated as 31384–56475 based on the"the QRE of the second day multiplied by 2–3" rule,which incorporates the reported final deaths 50500.The Quasi-Linear and Adaptive Estimation(QLAE)method adaptively adjusts the final fatality estimate within two days and predicts subsequent reported deaths.The correct order of magnitude of the final death toll can be estimated as early as 13 hr after the M_(S)8.0 earthquake.In addition,additional earthquakes such as May 12,2008,M_(S)8.1 Wenchuan earthquake(China),September 8,2023,M_(S)7.2 Al Haouz earthquake(Morocco),November 3,2023,M_(S)5.8 Mid-Western Nepal earthquake,December 18,2023,M_(S)6.1 Jishishan earthquake(China),January 1,2024,M_(S)7.2 Noto Peninsula earthquake(Japan)and August 8,2023,Maui,Hawaii,fires are added again to verified the correctness of the model.The fatalities from the Maui fires are found to be approximately equivalent to those resulting from an M_(S)7.4 earthquake.These methods complement existing frameworks such as Quake Loss Assessment for Response and Mitigation(QLARM)and Prompt Assessment of Global.展开更多
Since the Industrial Revolution,humanity’s extensive burning of fossil fuels(coal,oil,and natural gas)has led to a continuous rise in the concentration of greenhouse gases,such as carbon dioxide(CO_(2)),in the atmosp...Since the Industrial Revolution,humanity’s extensive burning of fossil fuels(coal,oil,and natural gas)has led to a continuous rise in the concentration of greenhouse gases,such as carbon dioxide(CO_(2)),in the atmosphere.According to data from the World Meteorological Organization(WMO),the global average CO_(2) concentration in 2023 exceeded 420×10^(−6),reaching the highest level in the past 800000 years.This has led to the increasing frequency of extreme climate events-such as glacier melting,sea-level rise,heatwaves,droughts,floods,and hurricanes-posing a severe threat to ecosystems and human society.展开更多
In high-rise building fires, the most immediate threat to passenger life and safety evacuation is the smoke inhalation. Some traditional models for smoke prevention and exhaust are analyzed and compared with the smoke...In high-rise building fires, the most immediate threat to passenger life and safety evacuation is the smoke inhalation. Some traditional models for smoke prevention and exhaust are analyzed and compared with the smoke-preventing air curtain. The rationality and the feasibility of the air curtain are theoretically expounded. The air volume, tuyere width and jet velocity in the air curtain experiment are designed according to the theoreti- cal calculation model. Experimental results indicate that the effect of air curtain to prevent smoke diffusion is re- markable as the volume ratio of air-smoke is about 0. 6, the jet angle is between 25^o and 35^o, and the jet thickness is between 25 mm and 45 mm. The efficiency of air curtain can reach 98% on the entraining effect. Meanwhile, experiments verify the theorectical calculation.展开更多
The effects of random long-range connections （shortcuts） on the transitions of neural firing patterns in coupled Hindmarsh-Rose neurons are investigated, where each neuron is subjected to an external current. It is ...The effects of random long-range connections （shortcuts） on the transitions of neural firing patterns in coupled Hindmarsh-Rose neurons are investigated, where each neuron is subjected to an external current. It is found that, on one hand, the system can achieve the transition of neural firing patterns from the fewer-period state to the multi-period one, when the number of the added shortcuts in the neural network is greater than a threshold value, indicating the occurrence of in-transition of neural firing patterns. On the other hand, for a stronger coupling strength, we can also find the similar but reverse results by adding some proper random connections. In addition, the influences of system size and coupling strength on such transition behavior, as well as the internality between the transition degree of firing patterns and its critical characteristics for different external stimulation current, are also discussed.展开更多
In the preparation of firing tables, the determination of projectile drag coefficientsthrough firing test radar data reduction is very important. Many methods have been developed for this work but none of them appear ...In the preparation of firing tables, the determination of projectile drag coefficientsthrough firing test radar data reduction is very important. Many methods have been developed for this work but none of them appear to be satisfactory in one Way or another. Inthis paper a multi-spline model of drag coefficient (cd) curve is developed that can guaranteefirst derivative continuity of the cd curve and has good flexibility of fitting accurately to acd curve from subsonic up to supersonic range. Practical firing data reduction tests showboth fast convergence and accurate fitting results. Typical velocity fitting RMS errors are0.05-0.08 m/s.展开更多
The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM...The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM) consistent with American standard test methodtogether with the semi-continuous emissions monitoring (SCEM) system as well as a mobile laboratoryfor mercury monitoring. The mercury and its speciation concentrations including participate mercuryat three locations of before air preheater, before electrostatic precipitator (ESP) and after ESPwere measured using the OHM and SCEM methods under normal operation conditions of the boiler systemas a result of firing a bituminous coal. The vapor-phase total mercury Hg(VT) concentration declinedwith the decrease of flue gas temperature because of mercury species transformation from oxidizedmercury to particulate mercury as the flue gas moved downstream from the air preheater to the ESPand after the ESP. A good agreement for Hg°, Hg^(2+) and Hg( VT) was obtained between the twomethods in the ash-free area. But in the dense particle-laden flue gas area, there appeared to be abig bias for mercury speciation owing to dust cake formed in the filter of OHM sampling probe. Theparticulateaffinity to the flue gas mercury and the impacts of sampling condition to accuracy ofmeasure were discussed.展开更多
Based on the porosity method and the improved non uniform QUICK scheme, this paper describes a three dimensional computer simulation to predict the flow characteristics in a tangentially fired boiler. The model is ap...Based on the porosity method and the improved non uniform QUICK scheme, this paper describes a three dimensional computer simulation to predict the flow characteristics in a tangentially fired boiler. The model is applied to a 600?MW boiler modeling under different operating conditions of reverse swirl of secondary air. The numerical results achieve reasonable agreement with experimental data. The calculated results of flow field, the pressure distribution, the relative diameter of tangential circle, angular momentum flux in furnace and the velocity distribution index in horizontal gas pass are analyzed in detail. And then the effects of the reverse swirl of secondary air on flue gas imbalance are discussed. Finally a reasonable operating condition of the reverse swirl of secondary air is presented.展开更多
AIM: To study the neural mechanism by which electroacupuncture(EA) at RN12(Zhongwan) and BL21(Weishu) regulates gastric motility.METHODS: One hundred and forty-four adult Sprague Dawley rats were studied in four separ...AIM: To study the neural mechanism by which electroacupuncture(EA) at RN12(Zhongwan) and BL21(Weishu) regulates gastric motility.METHODS: One hundred and forty-four adult Sprague Dawley rats were studied in four separate experiments. Intragastric pressure was measured using custommade rubber balloons, and extracellular neuron firing activity, which is sensitive to gastric distention in the dorsal vagal complex(DVC), was recorded by an electrophysiological technique. The expression levels of c-fos, motilin(MTL) and gastrin(GAS) in the paraventricular hypothalamic nucleus(PVN) were assayed by immunohistochemistry, and the expression levels of motilin receptor(MTL-R) and gastrin receptor(GAS-R) in both the PVN and the gastric antrum were assayed by western blotting.RESULTS: EA at RN12 + BL21(gastric Shu and Mu points), BL21(gastric Back-Shu point), RN12(gastric Front-Mu point), resulted in increased neuron-activating frequency in the DVC(2.08 ± 0.050, 1.17 ± 0.023, 1.55 ± 0.079 vs 0.75 ± 0.046, P < 0.001) compared with a model group. The expression of c-fos(36.24 ± 1.67, 29.41 ± 2.55, 31.79 ± 3.00 vs 5.73 ± 2.18, P < 0.001), MTL(22.48 ± 2.66, 20.76 ± 2.41, 19.17 ± 1.71 vs 11.68 ± 2.52, P < 0.001), GAS(24.99 ± 2.95, 21.69 ± 3.24, 23.03 ± 3.09 vs 12.53 ± 2.15, P < 0.001), MTL-R(1.39 ± 0.05, 1.22 ± 0.05, 1.17 ± 0.12 vs 0.84 ± 0.06, P < 0.001), and GAS-R(1.07 ± 0.07, 0.91 ± 0.06, 0.78 ± 0.05 vs 0.45 ± 0.04, P < 0.001) increased in the PVN after EA compared with the model group. The expression of MTL-R(1.46 ± 0.14, 1.26 ± 0.11, 0.99 ± 0.07 vs 0.65 ± 0.03, P < 0.001), and GAS-R(1.63 ± 0.11, 1.26 ± 0.16, 1.13 ± 0.02 vs 0.80 ± 0.11, P < 0.001) increased in the gastric antrum after EA compared with the model group. Damaging the PVN resulted in reduced intragastric pressure(13.67 ± 3.72 vs 4.27 ± 1.48, P < 0.001). These data demonstrate that the signals induced by EA stimulation of acupoints RN12 and BL21 are detectable in the DVC and the PVN, and increase the levels of gastrointestinal hormones and their receptors in the PVN and gastric antrum to regulate gastric motility. CONCLUSION: EA at RN12 and BL21 regulates gastric motility, which may be achieved through the PVN-DVCvagus-gastric neural pathway.展开更多
Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,...Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil characteristics.The impact on soil properties is intricate,yielding different results based on these factors.This paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such fires.Low-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in available nutrients and pH.High intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest soils.High intensity fires result in nutrient volatilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil biota.High soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological properties.In this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil heating.Furthermore,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire incidences.This review provides information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy ecosystems.In addition,the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.展开更多
基金Supported by a grant from the Education Department of Liaoning Province(2011196)~~
文摘This study aimed to probe into occurrence and development of spontaneous firings in the telencephalon neurons of Hynobius leechi . [Method] Mi-croelectrode technique was used to record extracellular spontaneous electrical activi-ties of the telencephalon neurons of H. leechi in occurrence and development. [Re-sult] There were three discharge types in the occurrence of telencephalon in H. leechi , with single spontaneous firing and consecutive single spontaneous firing being main-ly apparent. And among the five types in the development of telencephalon, the main discharge type was single spontaneous firing. Along with the occurrence and development of telencephalon, the extracellular discharge intensity enhanced gradual-ly, the discharge duration increased, and the spontaneous firing frequency accelerat-ed, al of which reached the maximum in the adult phase. Fol owing the process of occurrence and development, other discharge types appeared successively. [Conclu-sion] Along with the occurrence and development of the telencephalon in H. leechi , the neuronal excitability increases step by step and the neuronal electrical activities diversify gradual y.
基金Supported by the National Basic Research Program of China under Grant No 2005CB724301the National Natural Science Foundation of China under Grant No 61075108.
文摘The response of synchronously firing groups of population retinal ganglion cells(RGCs)to natural movies(NMs)and pseudo-random white-noise checker-board flickering(CB,as control)are investigated using an information-theoretic algorithm.The main results are:(1)the population RGCs tend to fire in synchrony far more frequently than expected by chance during both NM and CB stimulation;(2)more synchronous groups could be formed and each group contains more neurons under NM than CB stimulation;(3)the individual neurons also participate in more groups and have more distinct partners in NM than CB stimulation.All these results suggest that the synchronized firings in RGCs are more extensive and diverse,which may account for more effective information processing in representing the natural visual environment.
基金supported by the Natural Science Founda tion of Chongqing(Grant No.CSTB2024NSCQ-MSX0944)。
文摘This study constructs a dual-capacitor neuron circuit(connected via a memristor)integrated with a phototube and a thermistor to simulate the ability of biological neurons to simultaneously perceive light and thermal stimuli.The circuit model converts photothermal signals into electrical signals,and its dynamic behavior is described using dimensionless equations derived from Kirchhoff's laws.Based on Helmholtz's theorem,a pseudo-Hamiltonian energy function is introduced to characterize the system's energy metabolism.Furthermore,an adaptive control function is proposed to elucidate temperature-dependent firing mechanisms,in which temperature dynamics are regulated by pseudo-Hamiltonian energy.Numerical simulations using the fourth-order Runge-Kutta method,combined with bifurcation diagrams,Lyapunov exponent spectra,and phase portraits,reveal that parameters such as capacitance ratio,phototube voltage amplitude/frequency,temperature,and thermistor reference resistance significantly modulate neuronal firing patterns,inducing transitions between periodic and chaotic states.Periodic states typically exhibit higher average pseudo-Hamiltonian energy than chaotic states.Two-parameter analysis demonstrates that phototube voltage amplitude and temperature jointly govern firing modes,with chaotic behavior emerging within specific parameter ranges.Adaptive control studies show that gain/attenuation factors,energy thresholds,ceiling temperatures,and initial temperatures regulate the timing and magnitude of system temperature saturation.During both heating and cooling phases,temperature dynamics are tightly coupled with pseudoHamiltonian energy and neuronal firing activity.These findings validate the circuit's ability to simulate photothermal perception and adaptive temperature regulation,contributing to a deeper understanding of neuronal encoding mechanisms and multimodal sensory processing.
基金supported by the National Natural Science Foundation of China(Grant No.62571079)the Technological Innovation Projects in the Field of Artificial Intelligence in Liaoning Province(Grant No.2023JH26/10300011)+1 种基金the Basic Scientific Research Projects in the Department of Education of Liaoning Province(Grant No.LJ212410152049)the Liaoning Provincial Science and Technology Plan Joint Project(Grant No.2025-BSLH-041)。
文摘The human brain is a complex intelligent system composed of tens of billions of neurons interconnected through synapses,and its intricate network structure has consistently attracted numerous scientists to explore the mysteries of brain functions.However,most existing studies have only verified the biological mimicry characteristics of memristors at the single neuron-synapse level,and there is still a lack of research on memristors simulating synaptic coupling between neurons in multi-neuron networks.Based on this,this paper uses discrete memristors to couple dual discrete Rulkov neurons,and adds synaptic crosstalk between the two discrete memristors to form a neuronal network.A memristor-coupled dual-neuron map,called the Rulkov-memristor-Rulkov(R-M-R)map,is constructed to simulate synaptic connections between neurons in biological tissues.Then,the equilibrium points of the R-M-R map are studied.Subsequently,the effect of parameter variations on the dynamic performance of the R-M-R map is comprehensively analyzed using bifurcation diagram,phase diagram,Lyapunov exponent spectrum(LEs),firing diagram,and spectral entropy(SE)complexity algorithms.In the RM-R map,diverse categories of periodic,chaotic,and hyperchaotic attractors,as well as different states of firing patterns,can be observed.Additionally,different types of state transitions and coexisting attractors are discovered.Finally,the feasibility of the model in digital circuits is verified using a DSP hardware platform.In this study,the coupling principle of biological neurons is simulated,the chaotic dynamic behavior of the R-M-R map is analyzed,and a foundation is laid for deciphering the complex working mechanisms of the brain.
基金supported by the Natural Science Foundation of Guangdong Province,Nos.2019A1515010649(to WC),2022A1515012044(to JS)the China Postdoctoral Science Foundation,No.2018M633091(to JS).
文摘Transforming growth factor-beta 1(TGF-β1)has been extensively studied for its pleiotropic effects on central nervous system diseases.The neuroprotective or neurotoxic effects of TGF-β1 in specific brain areas may depend on the pathological process and cell types involved.Voltage-gated sodium channels(VGSCs)are essential ion channels for the generation of action potentials in neurons,and are involved in various neuroexcitation-related diseases.However,the effects of TGF-β1 on the functional properties of VGSCs and firing properties in cortical neurons remain unclear.In this study,we investigated the effects of TGF-β1 on VGSC function and firing properties in primary cortical neurons from mice.We found that TGF-β1 increased VGSC current density in a dose-and time-dependent manner,which was attributable to the upregulation of Nav1.3 expression.Increased VGSC current density and Nav1.3 expression were significantly abolished by preincubation with inhibitors of mitogen-activated protein kinase kinase(PD98059),p38 mitogen-activated protein kinase(SB203580),and Jun NH2-terminal kinase 1/2 inhibitor(SP600125).Interestingly,TGF-β1 significantly increased the firing threshold of action potentials but did not change their firing rate in cortical neurons.These findings suggest that TGF-β1 can increase Nav1.3 expression through activation of the ERK1/2-JNK-MAPK pathway,which leads to a decrease in the firing threshold of action potentials in cortical neurons under pathological conditions.Thus,this contributes to the occurrence and progression of neuroexcitatory-related diseases of the central nervous system.
文摘Neural damage or degeneration is at the crux of many diseases,and treatment of these diseases will require the development of therapeutics to enhance and guide neural regeneration.Both intrinsic and extrinsic factors dictate a neuron’s ability to regenerate,and the combination of these factors results in the great regenerative capacity of the peripheral nervous system(PNS)and the poor regenerative capacity of the central nervous system(CNS)following injury.At the core of a neuron’s function is its ability to relay electrochemical signals,and a neuron’s excitability is a key factor in its ability to regenerate.Recent works have focused on the changes in neuronal electrophysiological properties,firing patterns,and ion flux after injury,which differentially activate signaling pathways at the core of regeneration.The role of glia in neuron regeneration has long been studied.
文摘LONGQUAN,a historic city in east China’s Zhejiang Province,is renowned for its exquisite celadon ware,featuring fine texture and pure,jade-like glaze.The region has a potterymaking tradition that spans over 1,600 years.Its celadon firing technique originated during the Three Kingdoms Period(220-280)and reached its peak in the Southern Song Dynasty(1127-1279).Since the Song Dynasty(960-1368),Longquan was among the main suppliers of porcelain for the imperial court.From the 12th to the 15th centuries.
基金funded by National Natural Science Foundation of China(Grants No.42371282 and 42130508)the Second Ti-betan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK1006)Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2020055)。
文摘The interactions between fire,ecosystems,and climate are complex.Tropical ecosystems have dominated global active fires nowadays,yet its causes,mechanisms,and consequences remain relatively poorly understood.To in-vestigate temporal response of remotely-sensed active fires to intra-annual climate change,several 1-km datasets,including the Moderate-resolution Imaging Spectroradiometer Collection 6(MODIS C6)active fires and the Cli-matologies at High Resolution for the Earth’s Land Surface Areas(CHELSA)climate variables,were gathered to examine the climatic characteristics of active fire incidences,fire-climate correlations,and the average monthly response of active fire occurrences to climate change using the Geographic Information System(GIS)Fishnet tool,Theil-Sen Median slope estimation,Mann-Kendall significance test,and Pearson’s correlation.We concluded that climate variables’trends of nearly two-decade active fires displayed varied degrees of increment in precipitation(Pre),temperature(Tas),and surface downwelling shortwave radiation(Rsds)and inconsistent decrement in near-surface relative humidity(Hurs)and near-surface wind speed(sfcWind).MODIS multi-year(2003-2018)active fires were moderately to strongly correlated negatively with Pre and Hurs at 10 km grid-resolution but positively with sfcWind and Rsds,showing marked geographical variations in correlation direction and strength.The most significant finding is the newly observed inverse relationship between active fires and precipitation on both sides of the equator.High occurrence areas of active fires regularly appear back and forth along with latitudinal changes(at one-degree intervals)in monthly minimum precipitation between the tropical Northern and Southern Hemispheres.The present study contributes to exploring the underlying mechanism of fire-climate interactions against the backdrop of climate warming.
文摘On 30 September 2024,the UK shuttered its last remaining coal-fired power plant[1].The closure marks a historic milestone,the end of 142 years of coal fueled prosperity.The country opened the world’s first plant to supply electric streetlamps in 1882,spark-ing a global energy revolution that has led to today’s nearly univer-sally electrified world.
基金supported by the National Natural Science Foundation of China(No.41571062)the Fundamental Research Funds for the Central Universities(No.2021TS014)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2023-JC-YB-259).
文摘Formaldehyde(HCHO)is a high-yield product of the oxidation of volatile organic compounds(VOCs)released by anthropogenic activities,fires,and vegetations.Hence,we examined the spatiotemporal variation trends in HCHO columns observed using the Ozone Monitoring Instrument(OMI)during 2005–2021 across the Fenwei Plain(FWP)and analysed the source and variability of HCHO using multi-source data,such as thermal anomalies.The spatial distribution of the annualmean HCHO in the FWP increased from northwest to southeast during 2005–2021,and the high-value aggregation areas contracted and gradually clustered,forming a belt-shaped distribution area from Xi’an to Baoji,north of the Qinling Mountains.The annual mean HCHO concentration generally showed a two-step increase over the 17 years.Fires showed a single-peak trend in March and a double-peak M-shaped trend in March and October,whereas urban thermal anomalies(UTAs)showed an inverted U-shaped trend over 17 years,with peaks occurring in May.The HCHO peaks are mainly caused by the alternating contributions of fires and UTAs.The fires and UTAs(predominantly industrial heat sources)played a role in controlling the background level of HCHO in the FWP.Precipitation and temperature were also important influencing variables for seasonal variations,and the influence of plant sources on HCHO concentrations had significant regional characteristics and contributions.In addition,the FWP has poor dispersion conditions and is an aggregated area for the long-range transport of air pollutants.
基金supported by the National Natural Science Foundation of China(NSFC,grant number U2039207).
文摘Earthquakes can cause significant damage and loss of life,necessitating immediate assessment of the resulting fatalities.Rapid assessment and timely revision of fatality estimates are crucial for effective emergency decisionmaking.This study using the February 6,2023,M_(S)8.0 and M_(S)7.9 Kahramanmaras,Türkiye earthquakes as an example to estimate the ultimate number of fatalities.An early Quick Rough Estimate(QRE)based on the number of deaths reported by the Disaster and Emergency Management Presidency of Türkiye(AFAD)is conducted,and it dynamically adjusts these estimates as new data becomes available.The range of estimates of the final number of deaths can be calculated as 31384–56475 based on the"the QRE of the second day multiplied by 2–3" rule,which incorporates the reported final deaths 50500.The Quasi-Linear and Adaptive Estimation(QLAE)method adaptively adjusts the final fatality estimate within two days and predicts subsequent reported deaths.The correct order of magnitude of the final death toll can be estimated as early as 13 hr after the M_(S)8.0 earthquake.In addition,additional earthquakes such as May 12,2008,M_(S)8.1 Wenchuan earthquake(China),September 8,2023,M_(S)7.2 Al Haouz earthquake(Morocco),November 3,2023,M_(S)5.8 Mid-Western Nepal earthquake,December 18,2023,M_(S)6.1 Jishishan earthquake(China),January 1,2024,M_(S)7.2 Noto Peninsula earthquake(Japan)and August 8,2023,Maui,Hawaii,fires are added again to verified the correctness of the model.The fatalities from the Maui fires are found to be approximately equivalent to those resulting from an M_(S)7.4 earthquake.These methods complement existing frameworks such as Quake Loss Assessment for Response and Mitigation(QLARM)and Prompt Assessment of Global.
文摘Since the Industrial Revolution,humanity’s extensive burning of fossil fuels(coal,oil,and natural gas)has led to a continuous rise in the concentration of greenhouse gases,such as carbon dioxide(CO_(2)),in the atmosphere.According to data from the World Meteorological Organization(WMO),the global average CO_(2) concentration in 2023 exceeded 420×10^(−6),reaching the highest level in the past 800000 years.This has led to the increasing frequency of extreme climate events-such as glacier melting,sea-level rise,heatwaves,droughts,floods,and hurricanes-posing a severe threat to ecosystems and human society.
文摘In high-rise building fires, the most immediate threat to passenger life and safety evacuation is the smoke inhalation. Some traditional models for smoke prevention and exhaust are analyzed and compared with the smoke-preventing air curtain. The rationality and the feasibility of the air curtain are theoretically expounded. The air volume, tuyere width and jet velocity in the air curtain experiment are designed according to the theoreti- cal calculation model. Experimental results indicate that the effect of air curtain to prevent smoke diffusion is re- markable as the volume ratio of air-smoke is about 0. 6, the jet angle is between 25^o and 35^o, and the jet thickness is between 25 mm and 45 mm. The efficiency of air curtain can reach 98% on the entraining effect. Meanwhile, experiments verify the theorectical calculation.
文摘The effects of random long-range connections （shortcuts） on the transitions of neural firing patterns in coupled Hindmarsh-Rose neurons are investigated, where each neuron is subjected to an external current. It is found that, on one hand, the system can achieve the transition of neural firing patterns from the fewer-period state to the multi-period one, when the number of the added shortcuts in the neural network is greater than a threshold value, indicating the occurrence of in-transition of neural firing patterns. On the other hand, for a stronger coupling strength, we can also find the similar but reverse results by adding some proper random connections. In addition, the influences of system size and coupling strength on such transition behavior, as well as the internality between the transition degree of firing patterns and its critical characteristics for different external stimulation current, are also discussed.
文摘In the preparation of firing tables, the determination of projectile drag coefficientsthrough firing test radar data reduction is very important. Many methods have been developed for this work but none of them appear to be satisfactory in one Way or another. Inthis paper a multi-spline model of drag coefficient (cd) curve is developed that can guaranteefirst derivative continuity of the cd curve and has good flexibility of fitting accurately to acd curve from subsonic up to supersonic range. Practical firing data reduction tests showboth fast convergence and accurate fitting results. Typical velocity fitting RMS errors are0.05-0.08 m/s.
文摘The in-situ instrumentation technique for measuring mercury and itsspeciation downstream a utility 100 MW pulverized coal (PC) fired boiler system was developed andconducted by the use of the Ontario hydro method (OHM) consistent with American standard test methodtogether with the semi-continuous emissions monitoring (SCEM) system as well as a mobile laboratoryfor mercury monitoring. The mercury and its speciation concentrations including participate mercuryat three locations of before air preheater, before electrostatic precipitator (ESP) and after ESPwere measured using the OHM and SCEM methods under normal operation conditions of the boiler systemas a result of firing a bituminous coal. The vapor-phase total mercury Hg(VT) concentration declinedwith the decrease of flue gas temperature because of mercury species transformation from oxidizedmercury to particulate mercury as the flue gas moved downstream from the air preheater to the ESPand after the ESP. A good agreement for Hg°, Hg^(2+) and Hg( VT) was obtained between the twomethods in the ash-free area. But in the dense particle-laden flue gas area, there appeared to be abig bias for mercury speciation owing to dust cake formed in the filter of OHM sampling probe. Theparticulateaffinity to the flue gas mercury and the impacts of sampling condition to accuracy ofmeasure were discussed.
文摘Based on the porosity method and the improved non uniform QUICK scheme, this paper describes a three dimensional computer simulation to predict the flow characteristics in a tangentially fired boiler. The model is applied to a 600?MW boiler modeling under different operating conditions of reverse swirl of secondary air. The numerical results achieve reasonable agreement with experimental data. The calculated results of flow field, the pressure distribution, the relative diameter of tangential circle, angular momentum flux in furnace and the velocity distribution index in horizontal gas pass are analyzed in detail. And then the effects of the reverse swirl of secondary air on flue gas imbalance are discussed. Finally a reasonable operating condition of the reverse swirl of secondary air is presented.
基金Supported by The National Nature Science Foundation Council of ChinaNo.81473784+3 种基金the Natural Science Foundation of Anhui ProvinceNo.1408085MH166the Natural Science Foundation of Anhui University of Traditional Chinese MedicineNo.2013qn002
文摘AIM: To study the neural mechanism by which electroacupuncture(EA) at RN12(Zhongwan) and BL21(Weishu) regulates gastric motility.METHODS: One hundred and forty-four adult Sprague Dawley rats were studied in four separate experiments. Intragastric pressure was measured using custommade rubber balloons, and extracellular neuron firing activity, which is sensitive to gastric distention in the dorsal vagal complex(DVC), was recorded by an electrophysiological technique. The expression levels of c-fos, motilin(MTL) and gastrin(GAS) in the paraventricular hypothalamic nucleus(PVN) were assayed by immunohistochemistry, and the expression levels of motilin receptor(MTL-R) and gastrin receptor(GAS-R) in both the PVN and the gastric antrum were assayed by western blotting.RESULTS: EA at RN12 + BL21(gastric Shu and Mu points), BL21(gastric Back-Shu point), RN12(gastric Front-Mu point), resulted in increased neuron-activating frequency in the DVC(2.08 ± 0.050, 1.17 ± 0.023, 1.55 ± 0.079 vs 0.75 ± 0.046, P < 0.001) compared with a model group. The expression of c-fos(36.24 ± 1.67, 29.41 ± 2.55, 31.79 ± 3.00 vs 5.73 ± 2.18, P < 0.001), MTL(22.48 ± 2.66, 20.76 ± 2.41, 19.17 ± 1.71 vs 11.68 ± 2.52, P < 0.001), GAS(24.99 ± 2.95, 21.69 ± 3.24, 23.03 ± 3.09 vs 12.53 ± 2.15, P < 0.001), MTL-R(1.39 ± 0.05, 1.22 ± 0.05, 1.17 ± 0.12 vs 0.84 ± 0.06, P < 0.001), and GAS-R(1.07 ± 0.07, 0.91 ± 0.06, 0.78 ± 0.05 vs 0.45 ± 0.04, P < 0.001) increased in the PVN after EA compared with the model group. The expression of MTL-R(1.46 ± 0.14, 1.26 ± 0.11, 0.99 ± 0.07 vs 0.65 ± 0.03, P < 0.001), and GAS-R(1.63 ± 0.11, 1.26 ± 0.16, 1.13 ± 0.02 vs 0.80 ± 0.11, P < 0.001) increased in the gastric antrum after EA compared with the model group. Damaging the PVN resulted in reduced intragastric pressure(13.67 ± 3.72 vs 4.27 ± 1.48, P < 0.001). These data demonstrate that the signals induced by EA stimulation of acupoints RN12 and BL21 are detectable in the DVC and the PVN, and increase the levels of gastrointestinal hormones and their receptors in the PVN and gastric antrum to regulate gastric motility. CONCLUSION: EA at RN12 and BL21 regulates gastric motility, which may be achieved through the PVN-DVCvagus-gastric neural pathway.
文摘Forest fires are key ecosystem modifiers affecting the biological,chemical,and physical attributes of forest soils.The extent of soil disturbance by fire is largely dependent on fire intensity,duration and recurrence,fuel load,and soil characteristics.The impact on soil properties is intricate,yielding different results based on these factors.This paper reviews research investigating the effects of wildfire and prescribed fire on the biological and physico-chemical attributes of forest soils and provides a summary of current knowledge associated with the benefits and disadvantages of such fires.Low-intensity fires with ash deposition on soil surfaces cause changes in soil chemistry,including increase in available nutrients and pH.High intensity fires are noted for the complete combustion of organic matter and result in severe negative impacts on forest soils.High intensity fires result in nutrient volatilization,the break down in soil aggregate stability,an increase soil bulk density,an increase in the hydrophobicity of soil particles leading to decreased water infiltration with increased erosion and destroy soil biota.High soil heating(> 120℃) from high-intensity forest fires is detrimental to the soil ecosystem,especially its physical and biological properties.In this regard,the use of prescribed burning as a management tool to reduce the fuel load is highly recommended due to its low intensity and limited soil heating.Furthermore,the use of prescribed fires to manage fuel loads is critically needed in the light of current global warming as it will help prevent increased wildfire incidences.This review provides information on the impact of forest fires on soil properties,a key feature in the maintenance of healthy ecosystems.In addition,the review should prompt comprehensive soil and forest management regimes to limit soil disturbance and restore fire-disturbed soil ecosystems.
