This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond...This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond pulsed laser.The airflow rate and pulse delay are the main experimental variables.The evolution of plasma motion was recorded using ultrafast time-resolved optical shadowing.The experimental results demonstrate that the expansion velocities of the plasma and combustion wave are influenced differently by the sideblowing airflow at different airflow rates(0.2 Ma,0.4 Ma,and 0.6 Ma).As the flow rate of the sideblow air stream increases,the initial expansion velocities of the plasma and combustion wave gradually decrease,and the side-blow air stream increasingly suppresses the plasma.It is important to note that the target vapor is always formed and ionized into plasma during the combined pulse laser action.Therefore,the side-blown airflow alone cannot completely clear the plasma.Depending on the delay conditions,the pressure of the side-blowing airflow,the influence of inverse Bremsstrahlung radiation absorption and target surface absorption mechanisms can lead to a phenomenon known as the double combustion waves when using a nanosecond pulse laser.Both simulation and experimental results are consistent,indicating the potential for further exploration of fused silica targets in the laser field.展开更多
High-voltage pulse discharge(HVPD)rock fragmentation controls a plasma channel forming inside the rock by adjusting the electrical parameters,electrode type,etc.In this work,an HVPD rock fragmentation test platform wa...High-voltage pulse discharge(HVPD)rock fragmentation controls a plasma channel forming inside the rock by adjusting the electrical parameters,electrode type,etc.In this work,an HVPD rock fragmentation test platform was built and the test waveforms were measured.Considering the effects of temperature,channel expansion and electromagnetic radiation,the impedance model of the plasma channel in the rock was established.The parameters and initial values of the model were determined by an iterative computational process.The model calculation results can reasonably characterize the development of the plasma channel in the rock and estimate the shock wave characteristics.Based on the plasma channel impedance model,the temporal and spatial distribution characteristics of the radial stress and tangential stress in the rock were calculated,and the rock fragmentation effect of the HVPD was analyzed.展开更多
The effect of rectangle wave pulse current on solidification structure of ZA27 alloy was studied. The restdts show that the wave pattern relies on the frequency range of harmonic wave and the energy of pulse current w...The effect of rectangle wave pulse current on solidification structure of ZA27 alloy was studied. The restdts show that the wave pattern relies on the frequency range of harmonic wave and the energy of pulse current within the frequency range of pulse current. Imposed pulse current could induce the solidification system to oscillate. The frequency range and the relevant energy distribution of pulse current exert an influence on the amount of atoms involved for forming critical nucleus, the surface states of dusters in melt, the oscillating state of melt on the surface of dusters, the active energy of atom diffusion , the frequnce response of the resonance of bulk melt and the absorbability of the solidification system to the external work. Rectangle wave pulse current involves rich harmonic waves ; the amplitudes of high order of harmonic waves are higher and reduce slowly, so it has a better effect on inoculation and modification.展开更多
Physico-mechanical properties are critically important parameters for rocks. This study aims to examine some of the rock properties of quartz-mica schist(QMS) rocks in a cost-effective manner by establishing correla...Physico-mechanical properties are critically important parameters for rocks. This study aims to examine some of the rock properties of quartz-mica schist(QMS) rocks in a cost-effective manner by establishing correlations between non-destructive and destructive tests. Using simple regression analysis, good correlations were obtained between the pulse wave velocities and the properties of QMS rocks. The results were further improved by using multiple regression analysis as compared to those obtained by the simple linear regression analysis. The results were also compared to the ones obtained by other empirical equations available. The general equations encompassing all types of rocks did not give reliable results of rock properties and showed large relative errors, ranging from 23% to 1146%. It is suggested that empirical correlations must be investigated separately for different types of rocks. The general empirical equations should not be used for the design and planning purposes before they are verified at least on one rock sample from the project site, as they may contain large unacceptable errors.展开更多
The domain size of spiral waves is an important issue in studies of two-dimensional (2D) spatiotemporal patterns. In this work, we use the 2D complex Ginzburg-Landau equation (CGLE) as our model and find that an i...The domain size of spiral waves is an important issue in studies of two-dimensional (2D) spatiotemporal patterns. In this work, we use the 2D complex Ginzburg-Landau equation (CGLE) as our model and find that an initially big spiral can successfully transfer to several small spirals by applying a pulse array method. The impacts of several important factors, such as array density, controlling intensity and pulsing time, are investigated. This control approach may be useful for the control of 2D spatiotemporal patterns and has potential applications in the control of some realistic systems, such as meteorological and cardiac systems.展开更多
Objective To study the relation between serum calcium level and elevated BaPWV in Chinese subjects. Methods The relation between serum calcium level and elevated BaPWV was studied in 9 615 subjects. The mean value of...Objective To study the relation between serum calcium level and elevated BaPWV in Chinese subjects. Methods The relation between serum calcium level and elevated BaPWV was studied in 9 615 subjects. The mean value of left and right BaPWV was analyzed. BaPWV was defined as high when it was31 752.5 cm/s (the upper quartile) either side. Results The BaPWV and its elevated percentage progressively increased across the quartiles of the serum calcium level (P〈0.05). The prevalence of elevated BaPWV was significantly higher in subjects of the second, third and highest quartiles than in those of the lowest quartile (26.9%, 28.4%, and 33.2%vs 23.7%, P=0.0116, P=0.0004, and P〈0.0001). Logistic regression analysis revealed that the risk of elevated BaPWV was 1.32- fold higher in subjects of the highest quartile than in those of the lowest quartile (OR=1.32, 95%CI:1.08-1.60). Conclusion The elevated serum calcium level is related to an elevated BaPWV and a higher risk of arterial stiffness, independent of conventional risk factors, in middle-aged and elderly Chinese subjects.展开更多
The incidence of ischemic stroke in patients with diabetes is increasing. While brachial-ankle pulse wave velocity (BaPWV) and ankle-bra- chial index (ABI) are known to be associated with ischemic cardiovascular a...The incidence of ischemic stroke in patients with diabetes is increasing. While brachial-ankle pulse wave velocity (BaPWV) and ankle-bra- chial index (ABI) are known to be associated with ischemic cardiovascular and cerebrovascular diseases, whether these measures predict the risk of ischemic cerebrovascular disease in diabetic patients remains unclear. 117 patients with type 2 diabetes were enrolled in this study. According to the results of head magnetic resonance imaging, the patients were divided into a diabetes-only group (n = 55) and a diabetes and ischemic stroke group (n = 62). We then performed ABI and BaPWV examinations for all patients. Compared with the diabe- tes-only group, we found decreased ABI and increased BaPWV in the diabetes and ischemic stroke group. Multivariate logistic regression analyses revealed that BaPWV and ABI were risk factors for ischemic stroke in patients with type 2 diabetes. Our findings indicate that decreased ABI and increased BaPWV are objective indicators of increased risk of ischemic stroke in patients with type 2 diabetes.展开更多
Background: Semen evaluation is used to estimate the testicular function. In bulls, the spermatozoa present in the ejaculate are the result of a process that begun more than 2 mo earlier, bequeathing a delayed depicti...Background: Semen evaluation is used to estimate the testicular function. In bulls, the spermatozoa present in the ejaculate are the result of a process that begun more than 2 mo earlier, bequeathing a delayed depiction of the actual function of the testis. Since testis vascularization might be critical for the gonad function, selected pulse wave Doppler ultrasound parameters were assessed in this study, for instance the peak systolic velocity, the end diastolic velocity and the resistive index of the testicular artery along the spermatic cord, the marginal portion of the testicular artery and the intratesticular branches of the testicular artery both in healthy adult and young bulls.Correlations between these parameters and characteristics of semen that was collected numerous times, before and after the Doppler ultrasound examination.Results: The peak systolic velocity and the end diastolic velocity measured in the testicular artery along the spermatic cord(supratesticular artery – SA) were variable among the bulls and within individual bulls, likely due to the convoluted course of the vessel. The resistive index was found highly repeatable in the same bull. A reduction in the resistive index was found between the supratesticular artery and the marginal portion of the testicular artery(P < 0.01), and between the marginal portion of the testicular artery and the intratesticular branches of the testicular artery(P < 0.05). No differences were recorded for the pulse wave Doppler ultrasound parameters in young bulls compared with adults. A significant correlation was found between the resistive index of the marginal portion of the testicular artery and total sperm in the ejaculate(r = 0.516, P < 0.05), the immature sperm(r = 0.462, P < 0.05), the teratoid sperm(r = 0.375, P < 0.05), and the "Dag defect" sperm(r = 0.389, P < 0.05). Similarly, the resistive index of the intratesticular branches of the testicular artery were found correlated with the total sperm number in the ejaculate(r = 0.568, P < 0.05), the immature sperm(r = 0.523, P < 0.05), the teratoid sperm(r = 0.418, P < 0.05), and the "Dag defect" sperm(r = 0.341, P < 0.05).Conclusions: The data presented in this study suggest that the resistive index, measured at the marginal portion of the testicular artery, could be an easy-to-perform parameter to evaluate the spermatogenesis quality in young bulls and normal adults.展开更多
Based upon the blood vessel of being regarded as the elasticity tube, and that the tissue restricts the blood vessel wall, the rule of pulse wave propagation in blood vessel was studied. The viscosity of blood, the el...Based upon the blood vessel of being regarded as the elasticity tube, and that the tissue restricts the blood vessel wall, the rule of pulse wave propagation in blood vessel was studied. The viscosity of blood, the elastic modulus of blood vessel, the radius of tube that influenced the pulse wave propagation were analyzed. Comparing the result that considered the viscosity of blood with another result that did not consider the viscosity of blood, we finally discover that the viscosity of blood that influences the pulse wave propagation can not be neglected; and with the accretion of the elastic modulus the speed of propagation augments and the press value of blood stream heightens; when diameter of blood vessel reduces, the press of blood stream also heightens and the speed of pulse wave also augments. These results will contribute to making use of the information of pulse wave to analyse and auxiliarily diagnose some causes of human disease.展开更多
In this paper,we discuss the properties of ionization waves(IWs)in a multi-pulsed plasma jet while using the two-dimensional computational approach.The IWs are generated by application of three short negative pulses w...In this paper,we discuss the properties of ionization waves(IWs)in a multi-pulsed plasma jet while using the two-dimensional computational approach.The IWs are generated by application of three short negative pulses with a repetition frequency 12.5 MHz.The simulations are performed continuously during a single run while accounting for charges accumulated inside(surface charges)and outside(space charges)the tube.The plasma forming gas mixture(He/O2=99.8%/0.2%)is injected through the discharge tube into the surrounding humid air.We show that an IW can emerge from the tube exit at a pulse rising edge(as a negative IW)and at a falling edge of the same pulse(as a positive IW).It is demonstrated that remnants of the negative and positive charges play an essential role in the discharge evolution.The first pulse travels the shortest distance as it propagates through the initially non-ionized environment.The IWs developing during the second pulse essentially enlarge the plasma plume length.At the same time,the IWs generated by the third pulse eventually decay due to the remnants of charges accumulated during the previous pulses.Accumulated memory charges can lead to the IW extinction.展开更多
In Earth's high-latitude ionosphere, the poleward motion of east–west elongated auroral arcs has been attributed to standing hydromagnetic waves, especially when the auroral arcs appear quasi-periodically with a ...In Earth's high-latitude ionosphere, the poleward motion of east–west elongated auroral arcs has been attributed to standing hydromagnetic waves, especially when the auroral arcs appear quasi-periodically with a recurrence time of a few minutes. The validation of this scenario requires spacecraft observations of ultra-low-frequency hydromagnetic waves in the magnetosphere and simultaneous observations of poleward-moving auroral arcs near the spacecraft footprints. Here we present the first observational evidence from the multi-spacecraft THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission and the conjugated all-sky imager to support the scenario that standing hydromagnetic waves can generate the quasi-periodic appearance of poleward-moving auroral arcs. In this specific event, the observed waves were toroidal branches of the standing hydromagnetic waves, which were excited by a pulse in the solar wind dynamic pressure. Multi-spacecraft measurements from THEMIS also suggest higher wave frequencies at lower L shells (consistent with the distribution of magnetic field line eigenfrequencies), which indicates that the phase difference across latitudes would increase with time. As time proceeds, the enlarged phase difference corresponds to a lower propagation speed of the auroral arcs, which agrees very well with the ground-based optical data.展开更多
The purpose of this study was to assess the relationship between arterial stiffness, as measured by brachial-ankle pulse wave velocity (baPWV), and the presence of the metabolic syndrome (MS) in a Chinese populati...The purpose of this study was to assess the relationship between arterial stiffness, as measured by brachial-ankle pulse wave velocity (baPWV), and the presence of the metabolic syndrome (MS) in a Chinese population. A total of 4,445 subjects were enrolled. The prevalence of MS in for the general population, males and females, respectively. our study population was 21.7%, 17.2% and 25.6% With adjustments for age, gender, cigarette smoking, heart rate, total cholesterol, low-density lipoprotein (LDL) cholesterol, and the use of anti-hypertensive drug, the stepwise regression analysis showed that baPWV had a significant relationship with components of MS, including systolic blood pressure (P 〈 0.001), diastolic blood pressure (P 〈 0.001), glucose (P 〈 0.001), highdensity lipoprotein (HDL) cholesterol (P = 0.04), and triglycerides (P 〈 0.001), but no relationship with waist circumference (P = 0.25). With an increase in the number of the MS components, baPWV increased significantly both in women and men. This study indicated that the MS is indeed a risk factor for arterial stiffness. Monitoring of baPWV in patients with MS may help in identifying persons at high risk for cardiovascular disease.展开更多
Fibulin-1(FBLN-1),an elastin-associated extracellular matrix protein,has been found in blood and may play a role in the pathophysiological processes leading to cardiovascular disease(CVD).We aimed to investigate the r...Fibulin-1(FBLN-1),an elastin-associated extracellular matrix protein,has been found in blood and may play a role in the pathophysiological processes leading to cardiovascular disease(CVD).We aimed to investigate the relationship between fibulin-1 levels and the risk of CVD by evaluating vascular age derived from the Framingham Heart Study and brachial-ankle Pulse Wave Velocity(baPWV)in patients with asymptomatic hyperuricemia(AHU).In total,66 patients with AHU and 66 gender-and age-matched healthy individuals were enrolled.The plasma fibulin-1 levels were measured by immunochemistry.Patients with AHU presented significantly higher vascular age[median(interquartile range):54(22)vs.48(14)years,P=0.01]and baPWV[mean±SD:1373±223 vs.1291±177 cm/s,P=0.02]than the healthy subjects;however,no significant difference was observed in the plasma fibulin-1 level between the patients with AHU and healthy subjects[median(interquartile range):4018(3838)vs.3099(3405)ng/mL,P=0.31].A correlation between fibulin-1 levels and baPWV was observed only in patients with AHU(r=0.29,P=0.02);and there was also a suggestively statistically significant correlation between fibulin-1 levels and vascular age(r=0.22,P=0.08).However,these associations were rendered insignificant after adjustments for potential confounders.In healthy subjects,no correlation was observed between fibulin-1 levels and CVD risk.This study reveals that plasma fibulin-1 levels may reflect the CVD risk in patients with AHU,but the relationship is not robust.展开更多
We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations...We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations. Our simulations show that the THz spectra in low frequency regions are highly dependent on the carrier envelope phase(CEP) of driving laser pulses. Using an optimal CEP of few-cycle laser pulses, we can obtain broadband strong THz waves, due to the symmetry breaking of the laser-graphene system. Our results also show that the strength of the THz spectra depend on both the intensity and central wavelength of the laser pulses. The intensity dependence of the THz wave can be described by the excitation rate of graphene, while wavelength dependence can be traced back to the band velocity and the population of graphene. We find that a near single-cycle THz pulse can be obtained from graphene driven by a mid-infrared laser pulse.展开更多
BACKGROUND Heart rate variability(HRV) and pulse-wave velocity(PWV),indicators of cardiac function,are altered in patients with spinal cord injury(SCI),suggesting that autonomic cardiac function and arterial stiffness...BACKGROUND Heart rate variability(HRV) and pulse-wave velocity(PWV),indicators of cardiac function,are altered in patients with spinal cord injury(SCI),suggesting that autonomic cardiac function and arterial stiffness may underlie the high risk of cardiovascular complications in these patients.No study has simultaneously investigated HRV and PWV in the same patients.AIM To evaluate cardiovascular complications in SCI patients by comparing HRV and PWV between patients with and without SCI.METHODS In this cross-sectional pilot study,patients with(n = 60) and without SCI(n = 60) were recruited from December 7,2019 to January 21,2020.Each participant received a five-minute assessment of HRV and the cardiovascular system using the Medicore HRV Analyzer SA-3000 P.Differences in HRV and PWV parameters between participants with and without SCI were statistically examined.RESULTS We observed a significant difference between participants with and without SCI with respect to the standard deviation of all normal-to-normal intervals,square root of the mean sum of squared successive risk ratio interval differences,physical stress index,total power,very-low frequency,low frequency,high frequency,and arterial elasticity.CONCLUSION Patients with SCI have weaker sympathetic and parasympathetic activity as well as lower arterial elasticity compared to those without,suggesting that SCI may increase cardiac function loading.展开更多
Pulse wave contains human physiological and pathological information. Different people will exhibit different characteristics, and hence determining the characteristic points of the pulse wave of human physiological h...Pulse wave contains human physiological and pathological information. Different people will exhibit different characteristics, and hence determining the characteristic points of the pulse wave of human physiological health makes sense. It is common that we extract the characteristic value of pulse wave signal with the method based on wavelet transform on a small scale, and then determine the locations of the characteristic points by modulus maxima and modulus minima. Before determining characteristic value by detecting modulus maxima and modulus minima, we need to determine every period of the pulse wave. This paper presents a new kind of adaptive threshold determination method which is more effective. It can accurately determine every period of the pulse wave, and then extract characteristic values by modulus maxima and modulus minima in every period of the pulse wave. The method presented in this paper promotes the research utilizing pulse wave on health life.展开更多
The effect of delay time on photoelectron spectra and state populations of a four-level ladder K2 molecule is investigated by a pump1–pump2–probe pulse via the time-dependent wave packet approach. The periodical mot...The effect of delay time on photoelectron spectra and state populations of a four-level ladder K2 molecule is investigated by a pump1–pump2–probe pulse via the time-dependent wave packet approach. The periodical motion of the wave packet leads to the periodical change of the photoelectron spectra. The Autler–Townes triple splitting appears at zero delay time, double splitting appears at nonzero delay time between pump1 and pump2 pulses, and no splitting appears at nonzero delay time between pump2 and probe pulses. The periodical change of the state populations with the delay time may be due to the coupling effect between the two pulses. It is found that the selectivity of the state populations may be attained by regulating the delay time. The results can provide an important basis for realizing the optical control of molecules experimentally.展开更多
Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sect...Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sectional study,between May and November 2022,peripheral venous blood of151 VS patients(case group)and 233 volunteers(control group)were collected.Fourteen SNPs were identified in five genes encoding the components of the MMP-2 signaling pathway,assessed through carotid-femoral pulse wave velocity(cf PWV),and analyzed using multivariate logistic regression.The multigene influence on the risk of VS was assessed using multifactor dimensionality reduction(MDR)and generalized multifactor dimensionality regression(GMDR)modeling.Results Within the multivariate logistic regression models,four SNPs were screened to have significant associations with VS:chemokine(C-C motif)ligand 2(CCL2)rs4586,MMP2 rs14070,MMP2rs7201,and MMP2 rs1053605.Carriers of the T/C genotype of MMP2 rs14070 had a 2.17-fold increased risk of developing VS compared with those of the C/C genotype,and those of the T/T genotype had a19.375-fold increased risk.CCL2 rs4586 and MMP-2 rs14070 exhibited the most significant interactions.Conclusion CCL2 rs4586,MMP-2 rs14070,MMP-2 rs7201,and MMP-2 rs1053605 polymorphisms were significantly associated with the risk of VS.展开更多
基金funded by the International Science and Technology Cooperation Project of Jilin Provincial Department of Science and Technology(No.20230402078GH)。
文摘This study examines the impact of variations in side-blowing airflow velocity on plasma generation,combustion wave propagation mechanisms,and surface damage in fused silica induced by a combined millisecond-nanosecond pulsed laser.The airflow rate and pulse delay are the main experimental variables.The evolution of plasma motion was recorded using ultrafast time-resolved optical shadowing.The experimental results demonstrate that the expansion velocities of the plasma and combustion wave are influenced differently by the sideblowing airflow at different airflow rates(0.2 Ma,0.4 Ma,and 0.6 Ma).As the flow rate of the sideblow air stream increases,the initial expansion velocities of the plasma and combustion wave gradually decrease,and the side-blow air stream increasingly suppresses the plasma.It is important to note that the target vapor is always formed and ionized into plasma during the combined pulse laser action.Therefore,the side-blown airflow alone cannot completely clear the plasma.Depending on the delay conditions,the pressure of the side-blowing airflow,the influence of inverse Bremsstrahlung radiation absorption and target surface absorption mechanisms can lead to a phenomenon known as the double combustion waves when using a nanosecond pulse laser.Both simulation and experimental results are consistent,indicating the potential for further exploration of fused silica targets in the laser field.
基金support of National Natural Science Foundation of China(No.52177144)。
文摘High-voltage pulse discharge(HVPD)rock fragmentation controls a plasma channel forming inside the rock by adjusting the electrical parameters,electrode type,etc.In this work,an HVPD rock fragmentation test platform was built and the test waveforms were measured.Considering the effects of temperature,channel expansion and electromagnetic radiation,the impedance model of the plasma channel in the rock was established.The parameters and initial values of the model were determined by an iterative computational process.The model calculation results can reasonably characterize the development of the plasma channel in the rock and estimate the shock wave characteristics.Based on the plasma channel impedance model,the temporal and spatial distribution characteristics of the radial stress and tangential stress in the rock were calculated,and the rock fragmentation effect of the HVPD was analyzed.
基金Funded by the Natural Science Foundation of Gansu Province(No.ZS021-A25-027-C)
文摘The effect of rectangle wave pulse current on solidification structure of ZA27 alloy was studied. The restdts show that the wave pattern relies on the frequency range of harmonic wave and the energy of pulse current within the frequency range of pulse current. Imposed pulse current could induce the solidification system to oscillate. The frequency range and the relevant energy distribution of pulse current exert an influence on the amount of atoms involved for forming critical nucleus, the surface states of dusters in melt, the oscillating state of melt on the surface of dusters, the active energy of atom diffusion , the frequnce response of the resonance of bulk melt and the absorbability of the solidification system to the external work. Rectangle wave pulse current involves rich harmonic waves ; the amplitudes of high order of harmonic waves are higher and reduce slowly, so it has a better effect on inoculation and modification.
文摘Physico-mechanical properties are critically important parameters for rocks. This study aims to examine some of the rock properties of quartz-mica schist(QMS) rocks in a cost-effective manner by establishing correlations between non-destructive and destructive tests. Using simple regression analysis, good correlations were obtained between the pulse wave velocities and the properties of QMS rocks. The results were further improved by using multiple regression analysis as compared to those obtained by the simple linear regression analysis. The results were also compared to the ones obtained by other empirical equations available. The general equations encompassing all types of rocks did not give reliable results of rock properties and showed large relative errors, ranging from 23% to 1146%. It is suggested that empirical correlations must be investigated separately for different types of rocks. The general empirical equations should not be used for the design and planning purposes before they are verified at least on one rock sample from the project site, as they may contain large unacceptable errors.
文摘The domain size of spiral waves is an important issue in studies of two-dimensional (2D) spatiotemporal patterns. In this work, we use the 2D complex Ginzburg-Landau equation (CGLE) as our model and find that an initially big spiral can successfully transfer to several small spirals by applying a pulse array method. The impacts of several important factors, such as array density, controlling intensity and pulsing time, are investigated. This control approach may be useful for the control of 2D spatiotemporal patterns and has potential applications in the control of some realistic systems, such as meteorological and cardiac systems.
基金supported by the Key Laboratory for Endocrine and Metabolic Diseases,Ministry of Health(1994DP131044)National Nature Science Foundation of China(81170739,81170719,81222008,81370960)+3 种基金Shanghai New Excellent Youth Program(XYQ2011009)Shanghai Health Bureau(2011293)EFSD-CDS-Lilly Program for Collaborative Research between China and Europe(2011)Shanghai Shen Kang Hospital Development Center(SHDC12012301)
文摘Objective To study the relation between serum calcium level and elevated BaPWV in Chinese subjects. Methods The relation between serum calcium level and elevated BaPWV was studied in 9 615 subjects. The mean value of left and right BaPWV was analyzed. BaPWV was defined as high when it was31 752.5 cm/s (the upper quartile) either side. Results The BaPWV and its elevated percentage progressively increased across the quartiles of the serum calcium level (P〈0.05). The prevalence of elevated BaPWV was significantly higher in subjects of the second, third and highest quartiles than in those of the lowest quartile (26.9%, 28.4%, and 33.2%vs 23.7%, P=0.0116, P=0.0004, and P〈0.0001). Logistic regression analysis revealed that the risk of elevated BaPWV was 1.32- fold higher in subjects of the highest quartile than in those of the lowest quartile (OR=1.32, 95%CI:1.08-1.60). Conclusion The elevated serum calcium level is related to an elevated BaPWV and a higher risk of arterial stiffness, independent of conventional risk factors, in middle-aged and elderly Chinese subjects.
文摘The incidence of ischemic stroke in patients with diabetes is increasing. While brachial-ankle pulse wave velocity (BaPWV) and ankle-bra- chial index (ABI) are known to be associated with ischemic cardiovascular and cerebrovascular diseases, whether these measures predict the risk of ischemic cerebrovascular disease in diabetic patients remains unclear. 117 patients with type 2 diabetes were enrolled in this study. According to the results of head magnetic resonance imaging, the patients were divided into a diabetes-only group (n = 55) and a diabetes and ischemic stroke group (n = 62). We then performed ABI and BaPWV examinations for all patients. Compared with the diabe- tes-only group, we found decreased ABI and increased BaPWV in the diabetes and ischemic stroke group. Multivariate logistic regression analyses revealed that BaPWV and ABI were risk factors for ischemic stroke in patients with type 2 diabetes. Our findings indicate that decreased ABI and increased BaPWV are objective indicators of increased risk of ischemic stroke in patients with type 2 diabetes.
基金the Provincial Breeders Federation of Trento for their support
文摘Background: Semen evaluation is used to estimate the testicular function. In bulls, the spermatozoa present in the ejaculate are the result of a process that begun more than 2 mo earlier, bequeathing a delayed depiction of the actual function of the testis. Since testis vascularization might be critical for the gonad function, selected pulse wave Doppler ultrasound parameters were assessed in this study, for instance the peak systolic velocity, the end diastolic velocity and the resistive index of the testicular artery along the spermatic cord, the marginal portion of the testicular artery and the intratesticular branches of the testicular artery both in healthy adult and young bulls.Correlations between these parameters and characteristics of semen that was collected numerous times, before and after the Doppler ultrasound examination.Results: The peak systolic velocity and the end diastolic velocity measured in the testicular artery along the spermatic cord(supratesticular artery – SA) were variable among the bulls and within individual bulls, likely due to the convoluted course of the vessel. The resistive index was found highly repeatable in the same bull. A reduction in the resistive index was found between the supratesticular artery and the marginal portion of the testicular artery(P < 0.01), and between the marginal portion of the testicular artery and the intratesticular branches of the testicular artery(P < 0.05). No differences were recorded for the pulse wave Doppler ultrasound parameters in young bulls compared with adults. A significant correlation was found between the resistive index of the marginal portion of the testicular artery and total sperm in the ejaculate(r = 0.516, P < 0.05), the immature sperm(r = 0.462, P < 0.05), the teratoid sperm(r = 0.375, P < 0.05), and the "Dag defect" sperm(r = 0.389, P < 0.05). Similarly, the resistive index of the intratesticular branches of the testicular artery were found correlated with the total sperm number in the ejaculate(r = 0.568, P < 0.05), the immature sperm(r = 0.523, P < 0.05), the teratoid sperm(r = 0.418, P < 0.05), and the "Dag defect" sperm(r = 0.341, P < 0.05).Conclusions: The data presented in this study suggest that the resistive index, measured at the marginal portion of the testicular artery, could be an easy-to-perform parameter to evaluate the spermatogenesis quality in young bulls and normal adults.
文摘Based upon the blood vessel of being regarded as the elasticity tube, and that the tissue restricts the blood vessel wall, the rule of pulse wave propagation in blood vessel was studied. The viscosity of blood, the elastic modulus of blood vessel, the radius of tube that influenced the pulse wave propagation were analyzed. Comparing the result that considered the viscosity of blood with another result that did not consider the viscosity of blood, we finally discover that the viscosity of blood that influences the pulse wave propagation can not be neglected; and with the accretion of the elastic modulus the speed of propagation augments and the press value of blood stream heightens; when diameter of blood vessel reduces, the press of blood stream also heightens and the speed of pulse wave also augments. These results will contribute to making use of the information of pulse wave to analyse and auxiliarily diagnose some causes of human disease.
基金supported by the Ministry of Science and Higher Education of the Russian Federation(No.075-15-2021-1026 of November 15,2021)jointly by the National Key Research and Development Plan of China(No.2021YFE0114700)。
文摘In this paper,we discuss the properties of ionization waves(IWs)in a multi-pulsed plasma jet while using the two-dimensional computational approach.The IWs are generated by application of three short negative pulses with a repetition frequency 12.5 MHz.The simulations are performed continuously during a single run while accounting for charges accumulated inside(surface charges)and outside(space charges)the tube.The plasma forming gas mixture(He/O2=99.8%/0.2%)is injected through the discharge tube into the surrounding humid air.We show that an IW can emerge from the tube exit at a pulse rising edge(as a negative IW)and at a falling edge of the same pulse(as a positive IW).It is demonstrated that remnants of the negative and positive charges play an essential role in the discharge evolution.The first pulse travels the shortest distance as it propagates through the initially non-ionized environment.The IWs developing during the second pulse essentially enlarge the plasma plume length.At the same time,the IWs generated by the third pulse eventually decay due to the remnants of charges accumulated during the previous pulses.Accumulated memory charges can lead to the IW extinction.
基金supported by the National Natural Science Foundation of China (grant numbers 41774168 and 41421003)
文摘In Earth's high-latitude ionosphere, the poleward motion of east–west elongated auroral arcs has been attributed to standing hydromagnetic waves, especially when the auroral arcs appear quasi-periodically with a recurrence time of a few minutes. The validation of this scenario requires spacecraft observations of ultra-low-frequency hydromagnetic waves in the magnetosphere and simultaneous observations of poleward-moving auroral arcs near the spacecraft footprints. Here we present the first observational evidence from the multi-spacecraft THEMIS (Time History of Events and Macroscale Interactions during Substorms) mission and the conjugated all-sky imager to support the scenario that standing hydromagnetic waves can generate the quasi-periodic appearance of poleward-moving auroral arcs. In this specific event, the observed waves were toroidal branches of the standing hydromagnetic waves, which were excited by a pulse in the solar wind dynamic pressure. Multi-spacecraft measurements from THEMIS also suggest higher wave frequencies at lower L shells (consistent with the distribution of magnetic field line eigenfrequencies), which indicates that the phase difference across latitudes would increase with time. As time proceeds, the enlarged phase difference corresponds to a lower propagation speed of the auroral arcs, which agrees very well with the ground-based optical data.
基金support by grants from the National Key TechnologiesR&D Program of China during the 11th Five-Year Plan Period(2007BAI07A10)the Jiangsu Province Science and TechnologySupport Program(BE2009613)the 9th Six Talents Peak Project ofJiangsu Province(WS-022),and the Qing Lan Project
文摘The purpose of this study was to assess the relationship between arterial stiffness, as measured by brachial-ankle pulse wave velocity (baPWV), and the presence of the metabolic syndrome (MS) in a Chinese population. A total of 4,445 subjects were enrolled. The prevalence of MS in for the general population, males and females, respectively. our study population was 21.7%, 17.2% and 25.6% With adjustments for age, gender, cigarette smoking, heart rate, total cholesterol, low-density lipoprotein (LDL) cholesterol, and the use of anti-hypertensive drug, the stepwise regression analysis showed that baPWV had a significant relationship with components of MS, including systolic blood pressure (P 〈 0.001), diastolic blood pressure (P 〈 0.001), glucose (P 〈 0.001), highdensity lipoprotein (HDL) cholesterol (P = 0.04), and triglycerides (P 〈 0.001), but no relationship with waist circumference (P = 0.25). With an increase in the number of the MS components, baPWV increased significantly both in women and men. This study indicated that the MS is indeed a risk factor for arterial stiffness. Monitoring of baPWV in patients with MS may help in identifying persons at high risk for cardiovascular disease.
文摘Fibulin-1(FBLN-1),an elastin-associated extracellular matrix protein,has been found in blood and may play a role in the pathophysiological processes leading to cardiovascular disease(CVD).We aimed to investigate the relationship between fibulin-1 levels and the risk of CVD by evaluating vascular age derived from the Framingham Heart Study and brachial-ankle Pulse Wave Velocity(baPWV)in patients with asymptomatic hyperuricemia(AHU).In total,66 patients with AHU and 66 gender-and age-matched healthy individuals were enrolled.The plasma fibulin-1 levels were measured by immunochemistry.Patients with AHU presented significantly higher vascular age[median(interquartile range):54(22)vs.48(14)years,P=0.01]and baPWV[mean±SD:1373±223 vs.1291±177 cm/s,P=0.02]than the healthy subjects;however,no significant difference was observed in the plasma fibulin-1 level between the patients with AHU and healthy subjects[median(interquartile range):4018(3838)vs.3099(3405)ng/mL,P=0.31].A correlation between fibulin-1 levels and baPWV was observed only in patients with AHU(r=0.29,P=0.02);and there was also a suggestively statistically significant correlation between fibulin-1 levels and vascular age(r=0.22,P=0.08).However,these associations were rendered insignificant after adjustments for potential confounders.In healthy subjects,no correlation was observed between fibulin-1 levels and CVD risk.This study reveals that plasma fibulin-1 levels may reflect the CVD risk in patients with AHU,but the relationship is not robust.
基金Supported by the National Natural Science Foundation of China (Grant Nos.11764038,11864037,11765018,and 91850209)。
文摘We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations. Our simulations show that the THz spectra in low frequency regions are highly dependent on the carrier envelope phase(CEP) of driving laser pulses. Using an optimal CEP of few-cycle laser pulses, we can obtain broadband strong THz waves, due to the symmetry breaking of the laser-graphene system. Our results also show that the strength of the THz spectra depend on both the intensity and central wavelength of the laser pulses. The intensity dependence of the THz wave can be described by the excitation rate of graphene, while wavelength dependence can be traced back to the band velocity and the population of graphene. We find that a near single-cycle THz pulse can be obtained from graphene driven by a mid-infrared laser pulse.
文摘BACKGROUND Heart rate variability(HRV) and pulse-wave velocity(PWV),indicators of cardiac function,are altered in patients with spinal cord injury(SCI),suggesting that autonomic cardiac function and arterial stiffness may underlie the high risk of cardiovascular complications in these patients.No study has simultaneously investigated HRV and PWV in the same patients.AIM To evaluate cardiovascular complications in SCI patients by comparing HRV and PWV between patients with and without SCI.METHODS In this cross-sectional pilot study,patients with(n = 60) and without SCI(n = 60) were recruited from December 7,2019 to January 21,2020.Each participant received a five-minute assessment of HRV and the cardiovascular system using the Medicore HRV Analyzer SA-3000 P.Differences in HRV and PWV parameters between participants with and without SCI were statistically examined.RESULTS We observed a significant difference between participants with and without SCI with respect to the standard deviation of all normal-to-normal intervals,square root of the mean sum of squared successive risk ratio interval differences,physical stress index,total power,very-low frequency,low frequency,high frequency,and arterial elasticity.CONCLUSION Patients with SCI have weaker sympathetic and parasympathetic activity as well as lower arterial elasticity compared to those without,suggesting that SCI may increase cardiac function loading.
文摘Pulse wave contains human physiological and pathological information. Different people will exhibit different characteristics, and hence determining the characteristic points of the pulse wave of human physiological health makes sense. It is common that we extract the characteristic value of pulse wave signal with the method based on wavelet transform on a small scale, and then determine the locations of the characteristic points by modulus maxima and modulus minima. Before determining characteristic value by detecting modulus maxima and modulus minima, we need to determine every period of the pulse wave. This paper presents a new kind of adaptive threshold determination method which is more effective. It can accurately determine every period of the pulse wave, and then extract characteristic values by modulus maxima and modulus minima in every period of the pulse wave. The method presented in this paper promotes the research utilizing pulse wave on health life.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11704178 and 11764041)the Scientific Research Fund of Hunan Provincial Education Department,China(Grant No.15B204)
文摘The effect of delay time on photoelectron spectra and state populations of a four-level ladder K2 molecule is investigated by a pump1–pump2–probe pulse via the time-dependent wave packet approach. The periodical motion of the wave packet leads to the periodical change of the photoelectron spectra. The Autler–Townes triple splitting appears at zero delay time, double splitting appears at nonzero delay time between pump1 and pump2 pulses, and no splitting appears at nonzero delay time between pump2 and probe pulses. The periodical change of the state populations with the delay time may be due to the coupling effect between the two pulses. It is found that the selectivity of the state populations may be attained by regulating the delay time. The results can provide an important basis for realizing the optical control of molecules experimentally.
基金supported by the Construction of Prevention and Treatment System of Geriatric Syndromes Focusing on Disability and Dementia(No.21-1-2-2-zyyd-nsh)。
文摘Objective This study aimed to explore the association of single nucleotide polymorphisms(SNP)in the matrix metalloproteinase 2(MMP-2)signaling pathway and the risk of vascular senescence(VS).Methods In this cross-sectional study,between May and November 2022,peripheral venous blood of151 VS patients(case group)and 233 volunteers(control group)were collected.Fourteen SNPs were identified in five genes encoding the components of the MMP-2 signaling pathway,assessed through carotid-femoral pulse wave velocity(cf PWV),and analyzed using multivariate logistic regression.The multigene influence on the risk of VS was assessed using multifactor dimensionality reduction(MDR)and generalized multifactor dimensionality regression(GMDR)modeling.Results Within the multivariate logistic regression models,four SNPs were screened to have significant associations with VS:chemokine(C-C motif)ligand 2(CCL2)rs4586,MMP2 rs14070,MMP2rs7201,and MMP2 rs1053605.Carriers of the T/C genotype of MMP2 rs14070 had a 2.17-fold increased risk of developing VS compared with those of the C/C genotype,and those of the T/T genotype had a19.375-fold increased risk.CCL2 rs4586 and MMP-2 rs14070 exhibited the most significant interactions.Conclusion CCL2 rs4586,MMP-2 rs14070,MMP-2 rs7201,and MMP-2 rs1053605 polymorphisms were significantly associated with the risk of VS.