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Fuel ◽  
2022 ◽  
Vol 312 ◽  
pp. 122913
Author(s):  
Zhenqiang Yang ◽  
Yu Liu ◽  
Guowei Zhu ◽  
Jiahao Liu ◽  
Rui Xu ◽  
...  

2022 ◽  
Author(s):  
Wenbin Fu ◽  
Lin Zhao ◽  
Jian-xing Zhang ◽  
Si-ting Ye ◽  
Ling-cui Meng ◽  
...  

Abstract Background Atherosclerosis (AS) is a chronic arterial disease. Atherosclerosis related diseases, like myocardial infarctions (MI) and strokes have the highest mortality and disability rate. However, limited evidence verified the effects of acupuncture on arterial stiffness for subclinical atherosclerosis. We hypothesized that acupuncture could improve arterial stiffness in subclinical atherosclerosis and resist plaque progression. The aim of this study is to assess the effect of acupuncture on arterial elasticity via ultrafast pulse wave velocity (ufPWV) and explore the effect of acupuncture on lipid level and platelet function for subclinical atherosclerosis patients.MethodsThis was a randomized parallel controlled trial included 44 patients. Patients were assigned in a 1:1 ratio to acupuncture group and sham acupuncture group. Patients completed 24 treatments in total within 12 weeks of intervention. The primary outcome was ultrafast pulse wave velocity (ufPWV) assessed after every 4-weeks treatment; the secondary outcomes were carotid intima-media thickness (cIMT), blood lipid levels, fibrinogen (FIB) and blood platelet. Intention-to-treat (ITT) principle was applied and data sets were analyzed using SPSS 20.0 software.ResultsAmong the 44 randomly assigned patients, changes of right-side BS value in TA group (0.841) at week 12 were greater than SA group (-0.189), with a mean difference of 1.030 (95% CI, 0.320, 1.739; P=0.006). Similar results were observed in right-side ES, left-side BS, left-side ES at week 12. As to secondary outcomes, compared with SA group(1.08mm), the TA group(0.98mm) showed a significant decline in mean of left-side IMT at week 12. (Z= -2.118; P=0.034). There were no serious adverse events.ConclusionsAmong patients with Carotid intima-media thickening, both-side carotids arterial elasticity is significantly improved after 12-week acupuncture compared with sham acupuncture. The effects of acupuncture are more noticeable at week 12 during end-systole.Trial registrationThe trial was registered at http://www.chictr.org.cn (NO. ChiCTR1900025551, 31/08/2019)


2022 ◽  
Vol 509 (2) ◽  
Author(s):  
Nguyễn Đình Linh ◽  
Hồ Thị Kim Ngân ◽  
Trần Đức Hùng

Mục tiêu: Tìm hiểu mối liên quan giữa chỉ số huyết áp tâm thu cổ chân-cánh tay (Ankle Brachial Index – ABI), tốc độ lan truyền sóng mạch (pulse wave velocity - PWV) với mức độ tổn thương động mạch vành (ĐMV) ở bệnh nhân (BN) nhồi máu cơ tim (NMCT) cấp. Đối tượng và phương pháp nghiên cứu: Nghiên cứu mô tả cắt ngang trên 2 nhóm: nhóm bệnh gồm 60 người bị NMCT cấp và nhóm chứng gồm 33 người có cùng độ tuổi và các yếu tố nguy cơ và chụp ĐMV không tổn thương. Cả 2 nhóm đều  được đo ABI, PWV, chụp ĐMV, nhóm bệnh được đánh giá mức độ tổn thương theo thang điểm SYNTAX II. Kết quả: Tuổi trung bình của nhóm bệnh và nhóm chứng tương ứng là 67,05 ± 12,04 và 67,67 ± 6,80 năm. ABI của nhóm bệnh (1,04 ± 0,10) thấp hơn nhóm chứng (1,12 ± 0,13), p<0,01. PWV của nhóm bệnh (15,90 ±1,49 m/s) cao hơn nhóm chứng (13,32 ± 1,98 m/s), p<0,01. PWV ở nhóm tổn thương 1 nhánh và ≥2 nhánh tương ứng là 15,25 ± 1,09 m/s và 16,22 ± 1,57 m/s. Có sự tương quan chặt chẽ giữa PWV với điểm SYNTAX (r = 0,477; p<0,01). Kết luận: ở nhóm NMCT cấp PWV cao hơn và ABI thấp hơn nhóm chứng có ý nghĩa. PWV tương quan chặt chẽ với mức độ tổn thương ĐMV theo thang điểm SYNTAX II.


2022 ◽  
Vol 509 (2) ◽  
Author(s):  
Hồ Thị Kim Ngân ◽  
Nguyễn Đình Linh ◽  
Trần Đức Hùng

Mục tiêu: Đánh giá độ cứng động mạch bằng chỉ số vận tốc lan truyền sóng mạch (pulse wave velocity - PWV) ở bệnh nhân (BN) bị bệnh động mạch vành mạn tính (BĐMVMT). Đối tượng và phương pháp: Nhóm bệnh gồm 61 người bị BĐMVMT được chẩn đoán xác định bằng phương pháp chụp động mạch vành qua da có hẹp ≥50% đường kính lòng mạch và nhóm chứng gồm 31 người nghi ngờ bị BĐMVMT nhưng chụp động mạch vành không tổn thương hoặc tổn thương <50%. Cả 2 nhóm đều  được đo PWV. Kết quả: Tuổi trung bình của nhóm chứng và nhóm bệnh lần lượt là 68,26 ± 6,66 và 70,1 ± 7,15 năm. Tuổi  ≥65 chiếm tỷ lệ cao (nhóm chứng và nhóm bệnh lần lượt là 74,2%; 77,0%). Nhóm bệnh nam chiếm tỷ lệ cao (60,7%) hơn nữ (39,3%). PWV tăng (≥14 m/s) ở nhóm bệnh và nhóm chứng tương ứng là: Bên phải (82,0%; 32,3%). Bên trái (67,2%; 22,6%) p<0,05. PWV ở người bị THA của nhóm bệnh và chứng tương ứng là: 15,05 ± 0,61 m/s; 11,47 ± 1,53 m/s, ở người bị ĐTĐ: 15,89 ± 2,07 m/s; 14,06 ± 1,29 m/s, người hút thuốc lá: 15,76 ± 1,97; 13,82 ± 1,45 m/s, người thừa cân: 15,69 ± 1,79 m/s; 13,59 ± 2,12m/s. Kết luận: Nhóm bệnh có PWV tăng (≥14 m/s) chiếm tỷ lệ cao hơn nhóm chứng. Ở cùng độ tuổi, giới tính và các yếu tố nguy cơ (THA, ĐTĐ, hút thuốc lá, thừa cân) thì PWV ở nhóm bệnh đều cao hơn ở nhóm chứng có ý nghĩa thống kê với p<0,05.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 581
Author(s):  
Se-Beom Oh ◽  
Jongbeom Kim ◽  
Soon-Woo Han ◽  
Kyung-Mo Kim ◽  
Dong-Seok Yun ◽  
...  

Coal-fired power plants operating under Korea’s standard supercritical pressure operate in a high-temperature environment, with steam temperatures reaching 540 °C. A standard coal-fired power plant has a 30-year design life, and lifespan diagnosis is performed on facilities that have operated for more than 100,000 h or 20 years. Visual inspection, thickness measurements, and hardness measurements in the field are used to assess the degree of material degradation at the time of diagnosis. In this study, aging degradation was assessed using an electromagnetic acoustic transducer to measure the change in transverse ultrasonic propagation speed, and the results were compared to microstructural analysis and tensile test results. Based on the experimental results, it was found that the boiler tube exposed to a high-temperature environment during long-term boiler operation was degraded and damaged, the ultrasonic wave velocity was reduced, and the microstructural grains were coarsened. It was also confirmed through tensile testing that the tensile and yield strengths increased with degradation. Our findings prove that the degree of change in mechanical properties as a function of the material’s degradation state is proportional to the change in ultrasonic wave velocity.


Machines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 58
Author(s):  
Yujie Feng ◽  
Haijian Su ◽  
Yinjiang Nie ◽  
Honghui Zhao

Marble is a common rock used in many buildings for structural or ornamental purposes and is widely distributed in underground engineering projects. The rocks are exposed to high temperatures when a tunnel fire occurs, and they will be rapidly cooled during the rescue process, which has a great impact on the rock performance and the underground engineering stability. Therefore, the role of cyclic thermal shocks on the physical and mechanical properties of marble specimens was systematically investigated. Different cyclic thermal shock treatments (T = 25, 200, 400, 600, 800 °C; N = 1, 3, 5, 7, 9) were applied to marble specimens and the changes in mass, volume, density and P-wave velocity were recorded in turn. Then, the thermal conductivity, optical microscopy and uniaxial compression tests were carried out. The results showed that both the cyclic thermal shock numbers (N) and the temperature level (T) weaken the rock properties. When the temperature of a thermal shock exceeds 600 °C, the mass loss coefficient and porosity of the marble will increase significantly. The most noticeable change in P-wave velocity occurs between 200 and 400 °C, with a 52.98% attenuation. After three thermal shocks, the cyclic thermal shock numbers have little influence on the uniaxial compressive strength and Young’s modulus of marble specimens. Shear failure is the principal failure mode in marble specimens that have experienced severe thermal damage (high N or T). The optical microscopic pictures are beneficial for illustrating the thermal cracking mechanism of marble specimens after cyclic thermal shocks.


2022 ◽  
Author(s):  
Stefan Möstl ◽  
Fabian Hoffmann ◽  
Jan-Niklas Hönemann ◽  
Jose Ramon Alvero-Cruz ◽  
Jörn Rittweger ◽  
...  

Aim. Pulse wave velocity independently predicts cardiovascular risk. Easy to use single cuff oscillometric methods are utilized in clinical practice to estimate pulse wave velocity. We applied the approach in master athletes to assess possible beneficial effects of lifelong exercise on vascular health. Furthermore, we compared single cuff measurements with a two-cuff method in another cohort. Methods. We obtained single cuff upper arm oscillometric measurements thrice in 129 master athletes aged 35 to 86 years and estimated pulse wave velocity using the ArcSolver algorithm. We applied the same method in 24 healthy persons aged 24 to 55 years participating in a head down tilt bedrest study. In the latter group, we also obtained direct pulse wave velocity measurements using a thigh cuff.Results. Estimated pulse velocity very highly correlated with age (R2 = 0.90) in master athletes. Estimated pulse wave velocity values were located on the same regression line like values obtained in participants of the head down tilt bed rest study. The modest correlation between estimated and measured PWV (r² 0.40; p<0.05) was attenuated after adjusting for age; the mean difference between pulse wave velocity measurements was 1 m/s.Conclusion. Estimated pulse wave velocity mainly reflects the entered age rather than true vascular properties and, therefore, failed detecting beneficial effects of life long exercise.Funding. The AGBRESA-Study was funded by the German Aerospace Center (DLR), the European Space Agency (ESA, contract number 4000113871/15/NL/PG) and the National Aeronautics and Space Administration (NASA, contract number 80JSC018P0078). Fabian Hoffmann received funding by the DLR and the German Federal Ministry of Economy and Technology, BMWi (50WB1816). SM, JT and JJ were supported by the Austrian Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology, BMK (SPACE4ALL Project, FFG No. 866761).


2022 ◽  
Author(s):  
FABIJAN LULIĆ ◽  
ZDRAVKO VIRAG

Abstract This study evaluated Doppler mitral inflow variables changes from rest to post-exercise among 104 subjects with and without echocardiographic evidence of ischemic response (IR) to exercise (63.9 ± 11 years, 54% male, 32% with IR) who underwent a clinically indicated treadmill stress echo (TSE) test. The time from exercise cessation to imaging (TIME) was recorded. The changes (after TSE minus baseline values) in the peak E-wave velocity (∆E) [34.2 vs. 24.2, p = 0.024] and E-wave deceleration rate (∆DR) [348.0 vs. 225.7, p = 0.010] were bigger in ischemic than in nonischemic subjects, while the changes in the peak A-wave velocity (∆A) did not differ [7.9 vs. 15.0, p = 0.082]. The correlations between Doppler variables and IR, TIME, and TIME*IR interaction were analyzed. We observed a significant interaction between TIME and IR regarding ∆E and ∆DR. The differences in the regression line slopes of time courses for ∆E and ∆DR based on IR were significant: ∆E (–0.09 vs. –8.17, p = 0.037) and ∆DR (11.23 vs. –82.60, p = 0.022). Main findings: 1. Time courses after exercise of ∆E and ∆DR in subjects with and without IR were different. 2. ∆E and ∆DR did not differ between subjects with and without IR at exercise cessation (TIME = 0). 3. The simple main effect of ischemia on ∆E and ∆DR was significant at TIME of ≥3 min. Divergent time courses of ∆E and ∆DR after exercise might be promising for detecting diastolic dysfunction caused by ischemia.


Geophysics ◽  
2022 ◽  
pp. 1-49
Author(s):  
Yu-Tai Wu

Beishih Village of Hsinhua Township in southern Taiwan is a unique location for studying soil liquefaction. Soil liquefaction was observed at the same site after earthquakes in 1946, 2010, and 2016, each of which had a Richter magnitude greater than six. This recurrence provides an opportunity for analyzing soil condition variations resulting from soil liquefaction. Seismic data sets were collected in 2011, 2014, 2016, and 2017. We used seismic refraction tomography and the multichannel analysis of surface waves to estimate P- and S-wave velocities. In S-wave velocity profiles, low shear velocity zones were located beneath sand volcanoes shortly after two earthquakes and disappeared 4 years after a 2010 earthquake. However, the P-wave velocity is less sensitive to soil condition changes, possibly because groundwater obscures the effect of soil liquefaction on velocity profiles. In addition, we used seismic wave velocities to determine the importance of soil properties such as Poisson’s ratio, shear modulus, and porosity to identify the cause of the low shear velocity zone. Notably, although porosity decreased after soil grain rearrangement, sand and clay mixing increased the Poisson’s ratio, reducing the shear modulus of the soil. In addition, a soil layer between 2 and 7 m and a deeper layer below 10 m that resulted in sand volcanoes were both liquefied. We also considered how the evaluation of soil liquefaction potential could be affected by long-term variations in soil conditions and changes resulting from liquefaction. The factor of safety was used to evaluate the liquefaction potential of the site. The results revealed that the assessment conducted long after the earthquake underestimated risk because the soil developed shear strength after the earthquake.


Author(s):  
Kelly Jarvis ◽  
Michael B. Scott ◽  
Gilles Soulat ◽  
Mohammed S. M. Elbaz ◽  
Alex J. Barker ◽  
...  

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