The Process of a Laser-Supported Combustion Wave Induced by Millisecond Pulsed Laser on Aluminum Alloy

We study the process of a laser-supported combustion wave （LSCW） when an aluminum alloy is irradiated by a millisecond pulse laser based on the method of laser shadowgraphy. Under the condition of different laser parameters, the obtained results include the velocity, ignition threshold of LSCW and the variation law. The speed of LSCW increases with the laser energy under the same irradiation laser pulse width, and the speed of LSCW reduces with the increase of the laser pulse width under the same irradiation laser energy. Moreover, the ignition time of LSCW becomes shorter by increasing the laser number of the pulse and is not effected by changing the frequencies, when keeping the laser pulse width and energy unchanged. The results of the study can be applied in the laser propulsion technology and metal surface laser heat treatment, etc.

Effects of output waveforms on penetration for Nd :YAG laser welding

By using a Nd: YAG laser welding system devised for transmitting continuous, rectangular and pulsed waveforms, comprehensive and deep investigation is focused on the effects of several parameters of rectangular waveform and pulsed output wave superimposed on a rectangular waveform on the penetration depth of weld. Research results indicate that the average power, duty cycle, frequency and peak power of rectangular wave affect the weld penetration depth to different extent. Results of experiments and analysis also indicate that the pulse delay time, pulse width and the power ratio of pulse to rectangular waveform seriously influence the penetration when the pulsed wave is superimposed on a rectangular waveform.

Association between Gene Polymorphisms and SNP-SNP Interactions of the Matrix Metalloproteinase 2 Signaling Pathway and the Risk of Vascular Senescence

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.

Pilot study on the effect of flavonoids on arterial stiffness and oxidative stress in chronic kidney disease

BACKGROUND Flavonoids,the main class of polyphenols,exhibit antioxidant and antihypertensive properties.AIM To prospectively investigate the impact of flavonoids on arterial stiffness in patients with chronic kidney disease(CKD)stagesⅠ-Ⅳ.METHODS In this prospective,single-arm study,CKD patients with arterial hypertension and diabetes mellitus were enrolled.Baseline demographic,clinical,and laboratory variables were recorded.Patients received daily treatment with a phenol-rich dietary supplement for 3 months.Blood pressure,arterial stiffness(carotidfemoral pulse wave velocity,central pulse pressure),and oxidative stress markers(protein carbonyls,total phenolic compound,total antioxidant capacity)were measured at baseline and at study end.RESULTS Sixteen patients(mean age:62.5 years,87.5%male)completed the study.Following intervention,peripheral systolic blood pressure decreased significantly by 14 mmHg(P<0.001).Carotid-femoral pulse wave velocity decreased from 8.9 m/s(baseline)to 8.2 m/s(study end)(P<0.001),and central pulse pressure improved from 59 mmHg to 48 mmHg(P=0.003).Flavonoids also reduced oxidative stress markers including protein carbonyls(P<0.001),total phenolic compound(P=0.001),and total antioxidant capacity(P=0.013).CONCLUSION Flavonoid supplementation in CKD patients shows promise in improving blood pressure,arterial stiffness,and oxidative stress markers.

Ankle-brachial index and brachial-ankle pulse wave velocity are risk factors for ischemic stroke in patients with type 2 diabetes

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.

Correlations between ultrasonic pulse wave velocities and rock properties of quartz-mica schist

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.

Serum Calcium Level is Associated with Brachial-ankle Pulse Wave Velocity in Middle-aged and Elderly Chinese

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.

The value of pulse wave velocity in the diagnosis of coronary heart disease

Objective: Using receiver operating characteristics (ROC) curve to evaluate the value of pulse wave velocity (PWV) in the diagnosis of coronary heart disease (CHD). Methods: By using coronary angiography as golden diagnostic standard of CHD, 218 patients were divided into both CHD group (n=121) and non-CHD group (n = 97). All these patients received PWV test. The efficacy of PWV of each artery segments in the diagnosis of CHD was evaluated by ROC curve. The sensitivity and specificity were calculated with the golden diagnostic standard of CHD. Results:The PWV of right carotid to femoral artery (Rc-f), left carotid to femoral artery (Lc-f), right radial to carotid artery (Rc-r), left radial to carotid artery (Lc-r) in CHD group were significantly higher than that of non-CHD group (9. 31±1. 75 vs 7.60±1.59, P<0. 01; 9. 02±1.71 vs 7. 52±1.50, P<0. 01; 8. 69±1. 37 vs 8. 00±1. 27, P<0. 01; 8.52±1. 03 vs 8. 03±1. 2, P<0. 01 respectively). However, the PWV of both right and left femoral to ankle artery (Rf-a and Lf-a) had no significant differences between the two groups. We then compared the area under curve (AUC) of each ROC(AUCROC) of PWV of Rc-f, Lc-f Rc-r and Lc-r to evaluate their diagnostic efficacy for CHD. We found that AUCROC of Rc-f PWV was the biggest (AUCROC = 0. 818), at the peak point of its ROC curve, the PWV was 8. 32 m/s. PWV>8. 32 m/s of Rc-f could predict the presence of CHD with a sensitivity of 79% and specificity of 77%. Conclusion: The PWV of Rc-f, Lc-f, Rc-r, Lc-r are significantly higher in CHD group than that in non-CHD group, and PWV of Rc-f is the most accurate in the detection of CHD. The PWV>8. 32 m/s of RC-F is a valuable predictor of CHD.

Brachial-ankle pulse wave velocity is an independent predictor of carotid artery atherosclerosis in the elderly

Objective Brachial-ankle pulse wave velocity （baPWV） is widely used as a simple noninvasive measure of arterial softness. The aim of this study was to evaluate the usefulness of baPWV as a predictor of the carotid artery atherosclerosis in the elderly. Methods A total of 721 elderly participants （mean ~ SD age, 70.3 -4- 5.6years） were enrolled in the current study. All participant underwent both baPWV measurement and B-mode ultrasound for the intima-media thickness. Carotid atherosclerosis （CAS） was defined as the present of carotid plaque or and/or intima media thickness for at least 1.1 mm. Results A multivariate logistic regression analysis reveals that age, sex, brachial-ankle pulse wave velocity, smoking and LDL-C level showed a significant correlation with the presence of CAS. The odds ratios of CAS associated with a 500cm/s increase of brachial-ankle pulse wave velocity were 2.378 [95% confidence interval, 1.36 to 4.00, P〈0.05], 3.733 [95% confidence interval, 1.729 to 8.058, P〈0.01], 4.438 [95% confidence interval, 1.659 to 11.803, P〈0.01]. The baPWV significantly correlated with IMT by bivariate correlation analysis （r=-0.39; p=0.001）. After adjusting for factors influencing, baPWV all the same correlated with IMT （r=-0.35; p=0.001）.Conclusion These results indicate that brachial-ankle PWV is an independent predictor of CAS in the elderly.It also means that the direct measurement of arterial stiffness by this simple method may be of great help for the evaluation of carotid artherosclerosis, at least in the elderly

THE EFFECTS OF BLOOD VISCOELASTICITY ON THE PULSE WAVE IN ARTERIES

Based on Womersley' s theory, the frequency equation satisfied by a complex wave velocity of a pulse wave in arteries war generalized to viscoelastic blood, a general formula of the complex wave velocity with regard to both linearly viscoelastic arteries and linearly viscolelastic blood was obtained, and the effects of the viscoelastic property of blood on the phase velocity and the wave attenuation of the pulse wave using the formula systematically was discussed. It is concluded that the influence of the blood elasticity on the wave propagation of a pulse wave in arteries is weaker than that of the arterial viscosity and may be neglected in larger arteries.

NUMERICAL SIMULATION OF THE TEMPERATURE FIELD IN A SOLDER BALL UNDER PULSED LASER AND ITS EFFECT ON THE VIBRATION OF THE SOLDER

The research presented here is focused on the vibration condition of a small volume solder solder ball,which is placed on the surface of a soldering pad and is exerted a pulse modulated continuous wave laser heat source. Finite element method is applied to analyzed the temperature field in the solder ball, and experi- ment is conducted to test the vibration. the results show that,that, the temperature field flucturates with the same frequency as that of the laser pulse, which in turn causes a forced vibration of the same frequency in the liquid solder ball.

Relationship between the Plasma Fibulin-1 Levels,Pulse Wave Velocity,and Vascular Age in Asymptomatic Hyperuricemia

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.

ANALYSE OF PULSE WAVE PROPAGATION IN ARTERIES

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.

Altered heart rate variability and pulse-wave velocity after spinal cord injury

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.

Relationship between brachial-ankle pulse wave velocity and metabolic syndrome components in a Chinese population

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.

Deposition of cerium contained conversion films on LC4 alloy with square wave pulse method

Cerium contained conversion films were deposited on LC4 aluminum alloy usingsquare wave pulse (SWP) in a CeCl_3 solution with KMnO_4 as the oxidant. Energy dispersivespectroscopy (EDS) and scanning electron microscopy (SEM) were adopted to study the composition andthe morphology of the film. It is found that the film is composed of Al, Zn, Cu, and small amount ofcerium. The polarization curves of the specimens treated with SWP technique measured in 3.5% (massfraction) NaCl solution reveal that the film thus formed inhibits both the anodic and cathodicprocess of the corrosion of the specimen. The immersion tests of treated specimens in 3.5% NaClsolution indicate that the corrosion resistance of the SWP treated specimen is better than that ofthe untreated and is equivalent to or even better than that of the traditionally electro-chemicallytreated specimens.

A More Effective Method of Extracting the Characteristic Value of Pulse Wave Signal Based on Wavelet Transform

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.

Association of Estimated Pulse Wave Velocity and the Dynamic Changes in Estimated Pulse Wave Velocity with All-Cause Mortality among Middle-Aged and Elderly Chinese

Objective We aimed to clarify the association between estimated pulse wave velocity(ePWV)and the changes in ePWV with all-cause mortality among middle-aged and elderly Chinese.Methods Data were obtained from the China Health and Retirement Longitudinal Study(CHARLS)from 2011-2018.The ePWV was calculated using an equation that included age and mean blood pressure(MBP).The ΔePWV was assessed as the difference in ePWV between the first two waves.Cox proportional hazard models were used to determine the association between ePWV and ΔePWV with all-cause mortality after adjustment for potential confounders.Results Of 13,116 participants during a median follow-up of 7.0 years,1,356 deaths occurred.An increased ePWV was independently associated with all-cause mortality.The hazard ratio[95% confidence interval(CI)]for participants from the 1^(st)-4^(th) quartile groups was 1.00,1.69(1.31-2.18),3.09(2.44-3.91),and 8.54(6.78-10.75),respectively.Each standard deviation(SD)increment of ePWV increased the risk of all-cause mortality by 132%.Furthermore,theΔePWV was significantly associated with a 1.28-fold(95%CI,1.18-1.38)risk of all-cause mortality per SD increment.Conclusion This cohort study provided novel evidence from a Chinese population that an increased ePWV or progression of the ePWV was independently associated with all-cause mortality,which highlighted the importance of mitigating ePWV progression in clinical practice.

Broadband Terahertz Wave Generation from Monolayer Graphene Driven by Few-Cycle Laser Pulse

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.

INTRACELLULAR SOLITARY PULSE CALCIUM WAVES IN FROG SYMPATHETIC NEURONS

In certain extracellular environments, there would appear a kind of solitary pulse calcium waves in Rana pipiens sympathetic neurons, propagating inwards along the radial direction from the plasma membrane. To gain a deeper insight into the waves, a model describing intracellular calcium waves in frog sympathetic neurons was established. In the piecewise linear approximation, the present model is identical to the Sneyd model. Thus, with (Sneyd's) method, analytical expressions for the wave speed and profiles of 1-D solitary pulse wave were obtained. A wave speed of (21.5 μm/s) was deduced, which agrees rather well with experimental data.