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Sample records for brachial-ankle pulse wave

  1. Correlation of Arterial Stiffness and Bone Mineral Density by Measuring Brachial-Ankle Pulse Wave Velocity in Healthy Korean Women

    OpenAIRE

    Kim, Nam-Lee; Suh, Heuy-Sun

    2015-01-01

    Background An association between arterial stiffness and osteoporosis has previously been reported. Therefore, we investigated the relationship between arterial stiffness, measured by brachial-ankle pulse wave velocity, and bone mineral density in a sample of healthy women undergoing routine medical checkup. Methods We retrospectively reviewed the medical charts of 135 women who had visited the Health Promotion Center (between May 2009 and December 2012). Brachial-ankle pulse wave velocity wa...

  2. Aging Index using Photoplethysmography for a Healthcare Device: Comparison with Brachial-Ankle Pulse Wave Velocity

    OpenAIRE

    Hong, Kyung Soon; Park, Kyu Tae; Ahn, Jae Mok

    2015-01-01

    Objectives Recent studies have emphasized the potential information embedded in peripheral fingertip photoplethysmogram (PPG) signals for the assessment of arterial wall stiffening during aging. For the discrimination of arterial stiffness with age, the brachial-ankle pulse wave velocity (baPWV) has been widely used in clinical applications. The second derivative of the PPG (acceleration photoplethysmogram [APG]) has been reported to correlate with the presence of atherosclerotic disorders. I...

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

    OpenAIRE

    Zhou, Fang; Zhang, Haifeng; Yao, Wenming; Mei, Hongbin; Xu, Dongjie; Sheng, Yanhui; Yang, Rong; Kong, Xiangqing; Wang, Liansheng; Zou, Jiangang; Yang, Zhijian; Li, Xinli

    2014-01-01

    Abstract 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 our study population was 21.7%, 17.2% and 25.6% for the general population, males and females, respectively. With adjustments for age, gender, cigarette smoking, heart rate, total cholesterol, low-density l...

  4. Determinants of Brachial-Ankle Pulse Wave Velocity in Chinese Patients with Rheumatoid Arthritis

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    Ping Li

    2013-01-01

    Full Text Available Objective. To investigate the relationship between Brachial-ankle pulse wave velocity (baPWV, and its associated risk factors in Chinese patients with RA. Methods. 138 Chinese RA patients and 150 healthy subjects were included. baPWV of all the participants was measured. RA related factors were determined, as well as traditional cardiovascular risk factors. Results. baPWV was significant higher in RA group (1705.44 ± 429.20 cm/s compared to the healthy control group (1386.23 ± 411.09 cm/s (P<0.001. Compared with low baPWV group, high baPWV group patients were significantly older (P = 0.008 and taller (P = 0.033. Serum cholesterol (P = 0.035, triglycerides (P = 0.004, and LDL level (P = 0.006 were significantly higher in high baPWV group patients compared with low baPWV group patients. The baPWV of RA patients was positively correlated with age (r = 0.439, P<0.001, and serum cholesterol level (r = 0.231, P = 0.035, serum triglycerides level (r = 0.293, P<0.001, serum LDL level (r = 0.323, P = 0.003. Meanwhile, baPWV negatively correlated with the height of RA patients (r = −0.253, P = 0.043. Multivariate regression analysis showed that baPWV of RA group was independently associated with age and serum triglycerides level. Conclusions. The old age and high level of serum triglycerides may be the major determinants of arterial stiffness in Chinese RA patients.

  5. Relationships between Brachial-Ankle Pulse Wave Velocity and Peripheral Neuropathy in Type 2 Diabetes

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    Byung Kil Ha

    2012-12-01

    Full Text Available BackgroundBrachial-ankle pulse wave velocity (baPWV is known to be a good surrogate marker of clinical atherosclerosis. Atherosclerosis is a major predictor for developing neuropathy. The goal of this study was to determine the relationship between baPWV and diabetic peripheral neuropathy (DPN in patients with type 2 diabetes.MethodsA retrospective cross-sectional study was conducted involving 692 patients with type 2 diabetes. The correlation between increased baPWV and DPN, neurological symptoms, and neurological assessment was analyzed. DPN was examined using the total symptom score (TSS, ankle reflexes, the vibration test, and the 10-g monofilament test. DPN was defined as TSS ≥2 and an abnormal neurological assessment. Data were expressed as means±standard deviation for normally distributed data and as median (interquartile range for non-normally distributed data. Independent t-tests or chi-square tests were used to make comparisons between groups, and a multiple logistic regression test was used to evaluate independent predictors of DPN. The Mantel-Haenszel chi-square test was used to adjust for age.ResultsPatients with DPN had higher baPWV and systolic blood pressure, and were more likely to be older and female, when compared to the control group. According to univariate analysis of risk factors for DPN, the odds ratio of the baPWV ≥1,600 cm/sec was 1.611 (95% confidence interval [CI], 1.072 to 2.422; P=0.021 and the odds ratio in female was 1.816 (95% CI, 1.195 to 2.760; P=0.005.ConclusionIncreased baPWV was significantly correlated with peripheral neuropathy in patients with type 2 diabetes.

  6. Can we early diagnose metabolic syndrome using brachial-ankle pulse wave velocity in community population?

    Institute of Scientific and Technical Information of China (English)

    Li Xin; Zheng Liang; Wu Juanli; Ma Yunsheng; Masanori Munakata; Oleski Jessica; Zhang Lijuan

    2014-01-01

    Background The prevalence of metabolic syndrome (MetS) increased recently and there was still not a screening index to predict MetS.The aim of this study was to estimate whether brachial-ankle pulse wave velocity (baPVVV),a novel marker for systemic arterial stiffness,could predict MetS in Chinese community population.Methods A total of 2 191 participants were recruited and underwent medical examination including 1 455 men and 756 women from June 2011 to January 2012.MetS was diagnosed according to the criteria of the International Diabetes Federation (IDF).Multiple Logistic regressions were conducted to explore the risk factors of MetS.Receiver operating characteristic (ROC) curve was performed to estimate the ideal diagnostic cutoff point of baPWV to predict MetS.Results The mean age was (45.35±8.27) years old.In multiple Logistic regression analysis,the gender,baPWV and smoking status were risk factors to MetS after adjusting age,gender,baPWV,walk time and sleeping time.The prevalence of MetS was 17.48% in 30-year age population in Shanghai.There were significant differences (X2=96.46,P <0.05) between male and female participants on MetS prevalence.According to the ROC analyses,the ideal cutoff point of baPWV was 1 358.50 cm/s (AUC=60.20%) to predict MetS among male group and 1 350.00 cm/s (AUC=70.90%) among female group.Conclusion BaPWV may be considered as a screening marker to predict MetS in community Chinese population and the diagnostic value of 1 350.00 cm/s was more significant for the female group.

  7. Effects of Levocarnitine on Brachial-Ankle Pulse Wave Velocity in Hemodialysis Patients: A Randomized Controlled Trial

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    Terumi Higuchi

    2014-12-01

    Full Text Available Background and Aims: Atherosclerotic cardiovascular disease is the most common cause of mortality in patients with end-stage kidney disease. Chronic kidney disease patients often exhibit a deficiency in l-carnitine due to loss during hemodialysis (HD. We studied the effects of l-carnitine supplementation on brachial-ankle pulse wave velocity (baPWV, a marker of atherosclerosis, in HD patients. Methods: This was a prospective, open-label, randomized, parallel controlled, multi-center trial testing the anti-atherosclerotic efficacy of oral l-carnitine administration (20 mg/kg/day. HD patients (n = 176, mean age, 67.2 ± 10.3 years old; mean duration of HD, 54 ± 51 months with plasma free l-carnitine deficiency (<40 μmol/L were randomly assigned to the oral l-carnitine group (n = 88 or control group (n = 88 and monitored during 12 months of treatment. Results: There were no significant differences in baseline clinical variables between the l-carnitine and control groups. l-carnitine supplementation for 12 months significantly increased total, free, and acyl carnitine levels, and reduced the acyl/free carnitine ratio. The baPWV value decreased from 2085 ± 478 cm/s at baseline to 1972 ± 440 cm/s after six months (p < 0.05 to 1933 ± 363 cm/s after 12 months (p < 0.001 of l-carnitine administration, while no significant changes in baPWV were observed in the control group. Baseline baPWV was the only factor significantly correlated with the decrease in baPWV. Conclusions: l-carnitine supplementation significantly reduced baPWV in HD patients. l-carnitine may be a novel therapeutic strategy for preventing the progression of atherosclerotic cardiovascular disease.

  8. Association of Brachial-Ankle Pulse Wave Velocity and Cardiomegaly With Aortic Arch Calcification in Patients on Hemodialysis.

    Science.gov (United States)

    Shin, Ming-Chen Paul; Lee, Mei-Yueh; Huang, Jiun-Chi; Tsai, Yi-Chun; Chen, Jui-Hsin; Chen, Szu-Chia; Chang, Jer-Ming; Chen, Hung-Chun

    2016-05-01

    Aortic arch calcification (AoAC) is associated with cardiovascular and all-cause mortality in end-stage renal disease population. AoAC can be simply estimated with an AoAC score using plain chest radiography. The objective of this study is to evaluate the association of AoAC with brachial-ankle pulse wave velocity (baPWV) and cardiomegaly in patients who have undergoing hemodialysis (HD).We retrospectively determined AoAC and cardiothoracic ratio (CTR) by chest x-ray in 220 HD patients who underwent the measurement of baPWV. The values of baPWV were measured by an ankle-brachial index-form device. Multiple stepwise logistic regression analysis was used to identify the factors associated with AoAC score >4.Compared patients with AoAC score ≦4, patients with AoAC score >4 had older age, higher prevalence of diabetes and cerebrovascular disease, lower diastolic blood pressure, higher baPWV, higher CTR, higher prevalence of CTR ≧50%, lower total cholesterol, and lower creatinine level. After the multivariate stepwise logistic analysis, old age, cerebrovascular disease, high baPWV (per 100 cm/s, odds ratio [OR] 1.065, 95% confidence interval [CI] 1.003-1.129, P = 0.038), CTR (per 1%, OR 1.116, 95% CI 1.046-1.191, P = 0.001), and low total cholesterol level were independently associated with AoAC score >4.Our study demonstrated AoAC severity was associated with high baPWV and high CTR in patients with HD. Therefore, we suggest that evaluating AoAC on plain chest radiography may be a simple and inexpensive method for detecting arterial stiffness in HD patients. PMID:27175684

  9. Relationship Between Earlobe Crease and Brachial-ankle Pulse Wave Velocity in Non-hypertensive, Non-diabetic Adults in Korea

    OpenAIRE

    Choi, Sang In; Kang, Hee Cheol; Kim, Choon Ok; Lee, Seung Beom; Hwang, Won Ju; Kang, Dae Ryong

    2009-01-01

    OBJECTIVES Several studies have found a significant association between the presence of earlobe crease (ELC) and cardiovascular disease (CVD). Brachial-ankle Pulse Wave Velocity (baPWV) is a non-invasive and useful measure of arterial stiffness predicting cardiovascular events and mortality. However, few studies have reported the relationship between ELC and baPWV as a new measure of arterial stiffness. The purpose of this study was to determine whether ELC is related to baPWV in non-diabetic...

  10. The product of resting heart rate times blood pressure is associated with high brachial-ankle pulse wave velocity.

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    Anxin Wang

    Full Text Available OBJECTIVE: To investigate potential associations between resting heart rate, blood pressure and the product of both, and the brachial-ankle pulse wave velocity (baPWV as a maker of arterial stiffness. METHODS: The community-based "Asymptomatic Polyvascular Abnormalities in Community (APAC Study" examined asymptomatic polyvascular abnormalities in a general Chinese population and included participants with an age of 40+ years without history of stroke and coronary heart disease. Arterial stiffness was defined as baPWV≥1400 cm/s. We measured and calculated the product of resting heart rate and systolic blood pressure (RHR-SBP and the product of resting heart rate and mean arterial pressure (RHR-MAP. RESULTS: The study included 5153 participants with a mean age of 55.1 ± 11.8 years. Mean baPWV was 1586 ± 400 cm/s. Significant (P<0.0001 linear relationships were found between higher baPWV and higher resting heart rate or higher arterial blood pressure, with the highest baPWV observed in individuals from the highest quartiles of resting heart rate and blood pressure. After adjusting for confounding parameters such as age, sex, educational level, body mass index, fasting blood concentrations of glucose, blood lipids and high-sensitive C-reactive protein, smoking status and alcohol consumption, prevalence of arterial stiffness increased significantly (P<0.0001 with increasing RHR-SBP quartile (Odds Ratio (OR: 2.72;95%Confidence interval (CI:1.46,5.08 and increasing RHR-MAP (OR:2.10;95%CI:1.18,3.72. Similar results were obtained in multivariate linear regression analyses with baPWV as continuous variable. CONCLUSIONS: Higher baPWV as a marker of arterial stiffness was associated with a higher product of RHR-SBP and RHR-MAP in multivariate analysis. In addition to other vascular risk factors, higher resting heart rate in combination with higher blood pressure are risk factors for arterial stiffness.

  11. Relationship between resistant hypertension and arterial stiffness assessed by brachial-ankle pulse wave velocity in the older patient

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    Chung CM

    2014-09-01

    Full Text Available Chang-Min Chung,1,2 Hui-Wen Cheng,2 Jung-Jung Chang,2 Yu-Sheng Lin,2 Ju-Feng Hsiao,2 Shih-Tai Chang,1 Jen-Te Hsu2,31School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, 2Division of Cardiology, Chang Gung Memorial Hospital, Chiayi, 3Department of Medicine, College of Medicine, Chang Gung University, Taoyuan County, TaiwanBackground: Resistant hypertension (RH is a common clinical condition associated with increased cardiovascular mortality and morbidity in older patients. Several factors and conditions interfering with blood pressure (BP control, such as excess sodium intake, obesity, diabetes, older age, kidney disease, and certain identifiable causes of hypertension are common in patients resistant to antihypertensive treatment. Arterial stiffness, measured by brachial-ankle pulse wave velocity (baPWV, is increasingly recognized as an important prognostic index and potential therapeutic target in hypertensive patients. The aim of this study was to determine whether there is an association between RH and arterial stiffness. Methods: This study included 1,620 patients aged ≥65 years who were referred or self-referred to the outpatient hypertension unit located at a single cardiovascular center. They were separated into normotensive, controlled BP, and resistant hypertension groups. Home BP, blood laboratory parameters, echocardiographic studies and baPWV all were measured. Results: The likelihood of diabetes mellitus was significantly greater in the RH group than in the group with controlled BP (odds ratio 2.114, 95% confidence interval [CI] 1.194–3.744, P=0.010. Systolic BP was correlated in the RH group significantly more than in the group with controlled BP (odds ratio 1.032, 95% CI 1.012–1.053, P=0.001. baPWV (odds ratio 1.084, 95% CI 1.016–1.156, P=0.015 was significantly correlated with the presence of RH. The other factors were negatively correlated with the existence of RH.Conclusion: In

  12. The Independent and Joint Association of Blood Pressure, Serum Total Homocysteine, and Fasting Serum Glucose Levels With Brachial-Ankle Pulse Wave Velocity in Chinese Hypertensive Adults.

    Science.gov (United States)

    Liu, Xiaoyun; Sun, Ningling; Yu, Tao; Fan, Fangfang; Zheng, Meili; Qian, Geng; Wang, Binyan; Wang, Yu; Tang, Genfu; Li, Jianping; Qin, Xianhui; Hou, Fanfan; Xu, Xiping; Yang, Xinchun; Chen, Yundai; Wang, Xiaobin; Huo, Yong

    2016-09-28

    This study aimed to investigate the independent and joint association of blood pressure (BP), homocysteine (Hcy), and fasting blood glucose (FBG) levels with brachial-ankle pulse wave velocity (baPWV, a measure of arterial stiffness) in Chinese hypertensive adults.The analyses included 3967 participants whose BP, Hcy, FBG, and baPWV were measured along with other covariates. Systolic BP (SBP) was analyzed as 3 categories (SBP < 160 mmHg; 160 to 179 mmHg; ≥ 180 mmHg); Hcy as 3 categories (< 10 μmol/L; 10 to 14.9 μmol/L; ≥ 15.0 μmol/L) and FBG: normal (FBG < 5.6 mmol/L), impaired (5.6 mmol/L ≤ FBG < 7.0 mmol/L), and diabetes mellitus (FBG ≥ 7.0 mmol/L). We performed linear regression analyses to evaluate their associations with baPWV with adjustment for covariables.When analyzed individually, BP, Hcy, and FBG were each associated with baPWV. When BP and FBG were analyzed jointly, the highest baPWV value (mean ± SD: 2227 ± 466 cm/s) was observed in participants with FBG ≥ 7.0 mmol/L and SBP ≥ 180 mmHg (β = 432.5, P < 0.001), and the lowest baPWV value (mean ± SD: 1692 ± 289 cm/s) was seen in participants with NFG and SBP < 160 mmHg. When Hcy and FBG were analyzed jointly, the highest baPWV value (2072 ± 480 cm/s) was observed in participants with FBG ≥ 7.0 mmol/L and Hcy ≥ 15.0 μmol/L (β = 167.6, P < 0.001), while the lowest baPWV value (mean ± SD: 1773 ± 334 cm/s) was observed in participants with NFG and Hcy < 10 μmol/L.In Chinese hypertensive adults, SBP, Hcy, and FBG are individually and jointly associated with baPWV.Our findings underscore the importance of identifying individuals with multiple risk factors of baPWV including high SBP, FBG, and Hcy.

  13. Measure and analyze the brachial-ankle pulse wave velocity of 125 plots%飞行员肢体动脉硬化与吸烟关系分析

    Institute of Scientific and Technical Information of China (English)

    单清; 王惠贤

    2011-01-01

    Objective : To explore the situation and related factors of the arteriosclerosis between the smoking pilots and non - smoking pilots. By means:125 pilots were randomly selected and divided into two groups: smoking group and non - smoking group. Measure the brachial - ankle pulse wave velocity of each pilot by Arteriosclerosis Checking Instrument , record the height , weight , systolic pressure , diastolic pressure , pulse pressure , driving plane period and smoking period of each pilot of the groups and compare the data of Bapwv of different ages between smoking pilots and non - smoking pilots. Results : There was little difference in Bapwv between the smoking pilots and non - smoking pilots with ages younger than 30 and 30 to 39( P >0. 05 ). The Bapwv of the smoking pilots who are over 40 years old are obvious higher than those same age non - smoking pilots( P < 0. 05 ). Conclusion: The brachial - ankle arteriosclerosis situation of the smoking pilots can be diagnosed correspondingly early. And we may prevent , interpose and doctor the arteriosclerosis of the smoking pilots to keep their flight safe.%目的:探讨飞行员肢体动脉硬化程度与吸烟关系.方法:随机选择125名飞行员分为吸烟组和非吸烟组,应用动脉硬化测定仪测定臂踝脉搏波传导速度,同时确定飞行员身高、体重、收缩压、舒张压、脉压、飞行时间等.对比各年龄段吸烟组与非吸烟组飞行员臂踝脉搏波传导速度.结果:30岁以下和30 ~39岁飞行员吸烟组臂踝脉搏波传导速度与非吸烟组无明显差异(P>0.05);40岁以上飞行员吸烟组臂踝脉搏波传导速度较非吸烟组显著升高(P<0.05).结论:通过对臂踝脉搏波传导速度的测定可以相对早期发现飞行员中特别是吸烟飞行员中动脉硬化程度,做到早预防、早干预,确保飞行安全.

  14. Effect of blood lipid on the change of brachial-ankle pulse wave velocity among prehypertensive population%血脂水平对血压正常高值人群脉搏波传导速度的影响

    Institute of Scientific and Technical Information of China (English)

    王林; 帅平; 刘玉萍; 程幼夫; 杨华; 李婷欣; 龚立荣; 任姣姣; 王洪佳

    2014-01-01

    Objective To explore the effect of blood lipid and lipoprotein ratios on the change of brachial-ankle pulse wave velocity (baPWV) among prehypertensive subjects.Methods 11 611 subjects with normal blood pressure (BP) were divided into two groups,which was one with optimal blood pressure (B P < 120/80 mmHg) and the other with prehypertension (BP:120-139/80-89 mmHg).Height,weight,baPWV,fasting blood-glucose,TC,TG,LDL-C and HDL-C were detected.Results The abnormal rate ofbaPWV in prehypertension group was obviously higher than that in the optimal blood pressure group.For optimal blood pressure group,the abnormality of TG,TC,LDL-C,TC/HDL-C as well as LDL-C/HDL-C,caused the increase of baPWV significantly (P<0.001).For prehypertensive group,the abnormality of TC and LDL-C caused the significant increase of baPWV (P<0.001).Results from logistic regression analysis showed that except for age,BMI and fasting blood-glucose,TC/HDL-C increasing was the independent risk factor in optimal blood pressure group,while TG increasing was for the prehypertension group.Conclusion With different normal BP level,both abnormality of blood lipid and lipoprotein ratio were the independent risk factors for baPWV increasing.%目的 探讨血脂和脂蛋白比值对血压正常高值人群脉搏波传导速度的影响.方法 选择11 611名血压正常的健康体检者,分为正常血压值组(血压< 120/80 mmHg)和血压正常高值组(血压为120 ~ 139/80 ~ 89 mmHg).应用全自动动脉硬化仪测定人选者肱踝脉搏波传导速度(baPWV),同时测量身高、体重、FPG、TC、TG、HDL-C、LDL-C等指标,并计算HDL-C和TC/HDL-C比值、LDL-C/HDL-C比值.分析血脂和脂蛋白比值异常情况对不同血压组脉搏波传导速度的影响.结果 血压正常高值组的baPWV异常率均高于血压正常组.血压正常组中除HDL-C外,TC、TG、LDL-C、TC/HDL-C、LDL-C/HDL-C的升高均使baPWV的异常率显著增加(P<0.001).血压正常高值组中,TC

  15. 不同收缩压水平对臂踝脉搏波传导速度影响的研究%Effect of different levels of systolic blood pressure on brachial-ankle pulse wave velocity

    Institute of Scientific and Technical Information of China (English)

    王义; 陶杰; 董岩; 陈朔华; 高新颖; 季春鹏; 杨光; 郑瑶; 吴寿岭

    2014-01-01

    Objective To investigate the impact of different levels of systolic blood pressure on brachial-ankle pulse wave velocity(baPWV). Methods A total of 5 852 participants was selected with stratified random sampling from the 101 510 workers of Tangshan Kaiuan Company who had undergone a physical check-up program. 5 222 of them with integral data were recruited into this survey. According to SBP collected during the 2010-2011 health examination program,the population under observation was divided into four groups:optimal SBP(SBP<120 mmHg),high-normal blood pressure Ⅰ period(120 mmHg≤SBP<130 mmHg),high-normal blood pressure Ⅱ period (130 mmHg≤SBP<140 mmHg)and hypertension(SBP≥140 mmHg or SBP<140 mmHg but antihypertensive drug user). Multivariate logistic regression analysis was used to analyze the influence of different levels of systolic blood pressure on baPWV. Results 1)There were 3 132 males and 2 090 females in all the 5 222 participants with an average age of 55.1 years old. Their mean of baPWV was(1 587.57±400.71)cm/s,with the detection rates as 62%(baPWV≥1 400 cm/s). 2)The means of baPWV for the above groups of SBP were 1 322.19,1 456.27,1 544.78 and 1 827.77 cm/s, respectively,with detection rates of baPWV≥1 400 cm/s as 26.4%,49.3%,64.2% and 88.3%, respectively. 3)Results from the Multiple linear regression analysis revealed that β of SBP was 0.40,only ranking second,on age(0.48). 4)Data from the Multiple logistic regression analysis showed that after adjusting for age,gender and other risk factors,when compared to optimal SBP,factors as high-normal blood pressure Ⅰ period、high-normal blood pressure Ⅱ period and hypertension were risk factors for increasing baPWV,with OR values as 2.70(95%CI:2.20-3.32),4.56(95%CI:3.67-5.67)and 13.51(95%CI:10.87-16.78),respectively. Conclusion Higher SBP seemed an independent risk factor for the increase of baPWV.%目的:探讨不同收缩压(SBP)水平对臂踝脉搏波传导速度

  16. Relationship between resting heart rate and brachial-ankle pulse wave velocity in healthy Chinese population%静息心率与臂踝脉搏波传导速度的关系

    Institute of Scientific and Technical Information of China (English)

    陶杰; 李冬青; 董岩; 吴寿岭

    2014-01-01

    Objective To investigate the relationship between resting heart rate (RHR) and brachial-ankle pulse wave velocity (baPWV) in healthy Chinese population.Methods This was a retrospective cohort study,and a total of 5 852 participants were selected with stratified random sampling from the 101 510 workers of Tangshan Kailuan company who received the health examination during 2010-2011 including epidemiological investigation,biochemical indicators measurement and baPWV measurement.A total of 5 440 participants met the inclusion criteria (aged 40 years or older,without stroke,transient ischemic attack and myocardial infarction) and 5 153 participants (3 110 males,mean age (55.1 ± 11.8) years old) with integral data were finally recruited into the final analysis.The observation population was divided into four groups according to RHR collected during health examinations:quartile 1 (RHR≤63 beats/min,n =1 405) ; quartile 2 (63 beats/min < RHR≤69 beats/min,n =1 176) ; quartile 3 (69 beats/min < RHR ≤76 beats/min,n =1 322) ; quartile 4 (RHR > 76 beats/min,n =1 250).Multivariate logistic regression analysis was used to analyze the relationship between RHR and baPWV.Results (1) The mean baPWV was (1 586 ± 400) cm/s,and the detection rates of baPWV ≥1 400 cm/s was 61.8% (3 185/5 153).(2)The baPWV of quartile 1,2,3 and 4 were (1 511 ±338) cm/s,(1 533 ±329) cm/s,(1 574 ±368) cm/s and (1 734 ±462) cm/s,respectively,and the detection rates of baPWV≥ 1 400 cm/s were 54.7% (769/1 405),56.0% (658/1 176),63.1% (834/1 322) and 74.3%(929/1 150),respectively.(3) Multiple logistic regression analysis showed that the detection rates of baPWV were significantly higher in quartile 2,3 and 4 compared to quartile 1,and the OR values were 1.37 (95 % CI:1.11-1.69),1.96 (95 % CI:1.59-2.41) and 2.60 (95 % CI:2.07-3.25),respectively,after adjusting for age,gender and systolic blood pressure,body mass index,fasting blood glucose,triglyceride,total cholesterol

  17. Relationship between Blood Pressure Variability and Brachial-ankle Pulse Wave Velocity in Hypertensive Patients%高血压患者血压变异性与肱踝脉搏波传导速度的关系研究

    Institute of Scientific and Technical Information of China (English)

    王宁; 余振球

    2012-01-01

    目的 探讨高血压患者血压变异性与肱踝脉搏波传导速度(brachial-ankle pulse wave velocity,baPWV)的关系.方法 选择原发性高血压患者313例,根据baPWV值,将其分为两组:baPWV正常组(baPWV<1 400 cm/s)87例,baPWV升高组(baPWV≥1 400 cm/s)226例.比较两组患者年龄、性别构成比、血糖、血脂、血肌酐、血尿酸、血压及血压变异性.结果 单因素分析显示,baPWV升高组患者的年龄、胆固醇、低密度脂蛋白、高密度脂蛋白、24 h平均收缩压、24 h收缩压变异性及24 h舒张压变异性均高于baPWV正常组(P<0.05),代入Logistic回归分析显示年龄、胆固醇、高密度脂蛋白、24 h平均收缩压、24 h收缩压变异性及24 h舒张压变异性与baPWV呈相关性(P<0.05).结论 高血压患者24 h收缩压变异性和舒张压变异性是影响baPWV的独立因素.%Objective To explore the relationship between blood pressure variability and brachial - ankle pulse wave velocity ( baPWV ) in hypertensive patients. Methods Totally 313 patients with essential hypertension were enrolled in this study and divided into normal baPWV group ( baPWV < 1 400cm/s, n =87 ) and high baPWV group ( baPWV≥1 400cm/s, n= 226 ) based on their baPWV values. Age, gender ratio, fasting blood glucose ( FBG ), blood lipids including cholesterol ( CHO ), low - density lipoprotein cholesterol ( LDL ), and high - density lipoprotein cholesterol ( HDL ), serum creatinine ( Cr ), blood uric acid ( UA ), blood pressure, and blood pressure variability were measured. Results Univariate analysis revealed that age, CHO, LDL, HDL, 24 - hour systolic blood pressure, 24 - hour systolic blood pressure variability, and 24 -hour diastolic blood pressure variability were significantly higher in high baPWV group than in normal baPWV group ( P <0. 05 ). Multivariate Logistic regression analysis indicated that age, CHO, HDL, 24 -hour systolic blood pressure, 24 -hour systolic blood pressure variability

  18. 以年龄和血压分类的健康人群臂-踝脉搏波速度参考值的临床意义%Clinical significance of brachial-ankle pulse wave velocity in healthy people classified by blood pressure and age

    Institute of Scientific and Technical Information of China (English)

    陈大伟; 张婧; 姜树强; 刘超; 郑海芳; 靳英; 韩春雷; 王建昌

    2015-01-01

    目的:探讨以年龄和血压分类的一般健康人群的臂-踝脉搏波传导速度(baPWV)参考值的临床意义。方法选取30岁以上无心脑血管疾病的1750名健康体检者,收集 baPWV、血压、血糖、血脂、体质量指数、吸烟、饮酒及服药史等资料。结果校正年龄和血压后,糖尿病、降压和降脂药物与 baPWV 相关,排除这些因素的1237人作为参考值人群。baPWV 参考值随年龄和血压增加而增加。结论一般健康人群按年龄和血压分类的 baPWV 参考值,可为不同年龄段和血压状态下的健康体检人群判定 baPWV 检测结果和积极防治动脉硬化提供依据。%Objective To investigate the clinical significance of brachial-ankle pulse wave velocity(baP-WV)in healthy people who were classified by blood pressure and age.Methods A total of 1750 healthy subjects without cerebral-cardiovascular diseases in the physical examination were recruited.The data of baPWV,blood pres-sure,glucose,lipid,body mass index,smoking,alcohol drinking and drugs were collected.Results After adjusting for age and blood pressure,the diabetes,drugs for anti-hypertensive drugs and lipid-lowering drugs were related with baP-WV,and the rest 1237 persons without these factors were selected as control group.Conclusion The study provides the reference value of baPWV in healthy people classified by blood pressure and age,which may be valuable for the selection of baPWV test for people in different states of ages and blood pressure in health examination,and the preven-tion of arterial stiffness.

  19. Relationship among brachial ankle pulse wave velocity, hsCRP level and blood glucose level in patients with diabetes mellitus%糖尿病患者血糖水平与肱踝脉搏波传导速度及hsCRP水平的关系

    Institute of Scientific and Technical Information of China (English)

    王伟红; 邓正聪; 靳雪芹

    2015-01-01

    目的:研究2型糖尿病患者血糖水平与肱踝脉搏波传导速度(baPWV)及高敏C反应蛋白(hsCRP)水平的关系。方法:选择2型糖尿病患者102例,健康体检者60例(正常对照组)为研究对象,根据糖化血红蛋白水平2型糖尿病患者被分为:HbA1c正常组(44例,HbA1c≤6.5%)和HbA1c升高组(58例,HbA1c>6.5%),检测各组患者的baPWV及血脂、血糖及hsCRP水平,并进行比较。结果:与正常对照组比较,HbA1c正常组和 HbA1c升高组 hsCRP水平[(1.82±0.2) mg/L比(2.7±0.1) mg/L比(3.5±0.1) mg/L]均显著升高,baPWV[(1412±95) cm/s比(1755±72) cm/s比(2040±105) cm/s]显著增加(P均<0.05),且 HbA1c升高组 hsCRP水平和baPWV显著高于 HbA1c正常组(P均<0.05)。结论:2型糖尿病患者肱踝脉搏波传导速度和高敏C反应蛋白水平明显高于正常者,且血糖控制不理想者的明显高于血糖控制理想者的,积极控制患者血糖可延缓动脉粥样硬化进展。%Objective:To study the relationship among brachial ankle pulse wave velocity (baPWV ) ,level of high sensitive C reactive protein (hsCRP ) and blood glucose level in patients with type 2 diabetes mellitus (T2DM ) . Methods :A total of 102 T2DM patients and 60 healthy people undergoing physical examination (normal control group) were selected .According to level of glycosylated hemoglobin (HbA1c) ,T2DM patients were divided into normal HbA1c group (n=44 ,HbA1c≤6. 5% ) and HbA1c elevating group (n=58 ,HbA1c>6. 5% ) .BaPWV ,lev‐els of blood lipids ,blood glucose and hsCRP were measured and compared among above groups .Results:Compared with normal control group ,there were significant rise in hsCRP level [(1.82 ± 0.2) mg/L vs . (2.7 ± 0.1) mg/L vs . (3.5 ± 0.1) mg/L] and baPWV [ (1412 ± 95) cm/s vs . (1755 ± 72) cm/s vs . (2040 ± 105) cm/s] in normal HbA1c group and HbA1c elevating group (P<0.01 all) ,and hs

  20. Correlation between brachial-ankle pulse wave velocity and left ventricular hypertrophy in hypertensive patients%高血压患者肱踝动脉脉搏波传导速度与左心室肥厚的相关性

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      目的分析高血压患者肱踝动脉脉搏波传导速度(brachial-ankle pulse wave velocity,baPWV)与左心室肥厚的关系。方法入选2009年9月-2012年6月本院969例原发性高血压患者,按照左心室肥厚定义将其分为高血压伴左心室肥厚(n=380)、高血压不伴左心室肥厚(n=589)两组。应用全自动动脉硬化测定仪测定双侧baPWV,取双侧baPWV平均值。结果高血压伴左心室肥厚组baPWV水平明显高于高血压不伴左心室肥厚组(P<0.05)。线性相关分析表明高血压患者baPWV水平与室间隔厚度(r=0.139,P<0.01)、左心室后壁厚度(r=0.124,P<0.01)以及左心室重量指数呈正相关(r=0.312,P<0.01)。进一步应用多元线性回归分析调整了年龄、性别、体重指数、收缩压、舒张压、血糖、血清胆固醇、低密度脂蛋白胆固醇、高密度脂蛋白胆固醇、甘油三酯等心血管危险因素的影响后,baPWV与室间隔厚度(标化的相关系数β=0.125,P<0.05)、左心室后壁厚度(标化的相关系数β=0.131,P<0.05)以及左心室重量指数(标化的相关系数β=0.027,P<0.01)仍然相关。结论高血压患者baPWV与左心室肥厚密切相关。%Objective To analyze the correlation between brachial-ankle pulse wave velocity (baPWV) and left ventricular hypertrophy (LVH) in hypertensive patients. Methods A total 969 primary hypertensive patients admitted to our hospital from September 2009 to June 2012 were divided into hypertension with LVH group (n=380) and hypertension without LVH group (n=589). Their bilateral baPWV was measured with automatic arteriosclerosis detector and its average value was calculated. Results The baPWV value was significantly higher in hypertension with LVH group than in hypertension without LVH group (P < 0.05). Linear correlation analysis showed that the baPW value was positively correlated with the interventricular septal thickness (r=0.139;P <0.01), LV posterior wall

  1. Assessment value of brachial-ankle pulse wave velocity on severity of coronary disease in patients with coronary heart disease%臂踝脉搏波速度评估冠心病患者冠脉病变程度的临床价值

    Institute of Scientific and Technical Information of China (English)

    孙顺洋; 祁正军; 邵雪松; 时阳成

    2015-01-01

    Objective:To study assessment value of brachial‐ankle pulse wave velocity (baPWV) for severity of coro‐nary disease in patients with coronary heart disease (CHD) .Methods :According to SYNTAX score of coronary an‐giography ,a total of 206 CHD patients from our hospital were divided into mild group (n=74 ,SYNTAX score 32 scores) .Another 80 healthy subjects undergoing physical examinations were selected as healthy control group during the same period .BaPWV ,ankle brachial index (ABI) and carotid -femoral pulse wave velocity (cfPWV) were measured and compared among all groups .Pearson correlation analysis was used to analyze the correlation among baPWV ,cfPWV ,ABI and SYNTAX score in CHD patients ;multi -factor Logistic regression model was used to analyze whether baPWV ,cfPWV and ABI were risk factors for SYNTAX scores .Results:Compared with healthy control group ,there were significant rise in baPWV [ (1.2 ± 0.3) m/s vs .(1.5 ± 0.4) m/s vs .(1.8 ± 0.6) m/s vs . (2.0±0.7)m/s]andcfPWV [ (1.3±0.5)m/svs.(2.5±0.7)m/svs.(2.9±0.8)m/svs.(3.4±0.7)m/s]in mild group ,medium group and severe group (Pmild group in turn ,there was significant difference by pairwise comparisons ( P<0.05 all);significant reduction in ABI [ (1.02 ± 0.32) vs .(0.82 ± 0.24) vs .(0.73 ± 0.16) vs .(0.56 ± 0.09)] in mild group , medium group and severe group ,and that of severe group was < medium group ,and < mild group in turn ,there was significant difference by pairwise comparisons ( P<0.05 all) .Pearson correlation analysis indicated that baPWV and cfPWV were positively correlated with SYNTAX score ( r= 0.613 , P= 0.007;r=0.528 , P=0.023) ,while ABI had no correlation with SYNTAX score .Multi-factor Logistic regression analysis indicated that diabetes melli‐tus ,hypertension ,baPWV and cfPWV were risk factors for SYNTAX score (OR=4.016~5.809 , P<0.05 or <0.01) .Conclusion:The baPWV can effectively assess severity of coronary disease in CHD patients .%目的:研究臂-踝

  2. 不同水平的低密度脂蛋白胆固醇人群踝肱脉搏波传导速度的研究%The Researchon Brachial-ankle Pulse Wave Velocity with Different Level of Low Density Lipoprotein Cholesterol

    Institute of Scientific and Technical Information of China (English)

    李小玲; 李颖; 王瑞涛

    2012-01-01

    目的 研究不同水平低密度脂蛋白胆固醇(LDL-C)与踝肱脉搏波传导速度(baPWV)的关系,探讨影响动脉弹性的主要因素.方法 从哈尔滨医科大学附属第二医院体检中心2010年4月-2011年10月的体检人群中随机抽取1 075例(男728例)作为研究对象.按照血清LDL-C水平分为4组:LDL-C正常组(C组,LDL-C<3.42 mmol/L);LDL-C临界升高组(H1组,LDL-C 3.42 mmol/L~4.20 mmol/L);LDL-C升高组(H2组,LDL-C:4.21 mmol/L~4.97 mmol/L);LDL-C显著升高组(H3组,LDL-C≥4.98 mmol/L).测定各组体检者的baPWV和踝肱指数(ABI),及其他临床指标,并行组间比较分析.结果 高LDL-C组baPWV值显著高于LDL-C正常组(1 391.74 cm/s±224.74 cm/s比1 310.49 cm/s±222.10 cm/s,P=0.027).C组和H1组baPWV值处于正常范围,且H1组baPWV值(1 351.77 cm/s±229.88 cm/s)明显高于C组(1 310.49 cm/s±222.02 cm/s),差异有统计学意义(P=0.012),H2组baPWV值和H3组baPWV值轻度升高,与C组、Hl组差异有统计学意义(P=0.00).各组间ABI值差异无统计学意义(P=0.221).baPWV逐步线性回归分析显示,收缩压(SBP)、年龄、LDL-C、高密度脂蛋白胆固醇(HDL-C)、尿酸(UA)均是影响baPWV的独立危险因素.且在控制SBP、年龄、HDL-C、UA影响因素后,LDL-C仍然与baPWV存在相关性(r=0.078,P=0.012).结论 随着LDL-C的升高,baPWV值增高,LDL-C升高者早期动脉血管弹性下降,baPWV检测有助于发现LDL-C升高的早期动脉粥样硬化.%Objective To study the relationship between the level of low density lipoprotein cholesteroKLDL - C) and branch - ankle pulse wave velocity. Methods A group of 1 075 subjects were selected and were classified into four groups: Normal LDL - C group (C group, LDL-C<3. 41 mmol/L) ; supercritical LDL - C group (H1 group, LDL - C:3. 42 to 4. 20 mmol/L) , high LDL - C group (H2 group,LDL - C:4. 21 to 4. 97 mmol/L) ;Severe high LDL - C group (H3 group,LDL - C≥4. 98 mmol/L) based on the National Cholesterol Education Program Ⅲ criteria

  3. 臂踝脉搏波速度和代谢综合征危险因素的相关性%The relationship between brachial- ankle pluse wave velocity and the risk factors of metabolic syndrome

    Institute of Scientific and Technical Information of China (English)

    任蔚虹; 潘海燕; 来鸣

    2010-01-01

    目的 探讨臂踝脉搏波速度(BaPWV)和代谢综合征危险因素的相关性.方法 入选2 753例体检者,年龄25~82岁,平均(44.7±9.6)岁,进行BaPWV、身高、体重、心率、血压的测量,收集空腹血糖、总胆固醇、甘油三酯、HDL和LDL.根据代谢综合征危险因素的个数分为4组,比较4组之间BaPWV的差异.其中将具有2个及2个以上危险因素的人群视为代谢综合征高危人群.结果 4组之间采用方差分析,组与组之间在基本资料和BaPWV方面均有显著差异,具有统计学意义(P<0.05),多元线性回归显示年龄、HR、BMI、血糖、甘油三酯、HDL、PP、SBP是代谢综合征高危人群BaPWV的相关因素(R2=0.566),而SBP、年龄、HR、血糖、BMI是影响BaPWV的独立相关因素.结论 BaPWV随着代谢综合征的危险因素个数增加而升高,SBP、年龄、HR、血糖、BMI是BaPWV的独立影响因素.%Objective To investigate the relationship between Brachial-ankle pulse wave velocity (BaPWV) and metabolic syndrome (MetS) risk factors. Methods 2 753 people who came to have a medical check - up, aged 25 to 82 years, [(44. 7 ± 9. 6) years old] were seleeted. BaPWV,height,weight,blood pressure,fasting glucose,triglycerides,HDL cholesterol,LDL cholesterol were measured. The people were divided into four groups based on the numbers of the MetS risk factors. The people who had two and more than two risk factors to be "the high risk factors group"were considered. Results In the four groups,there were significant differences among them(P <0. 05). Multiple linear regression analysis demonstrated that age,heart rate,BMI,fasting glucose,triglycerides,HDL cholesterol,pulse pressure,and SBP were associated with BaPWV ( R2 square =0. 566) in "the high risk factors group" ,and stepwise regression analysis revealed that SBP,age ,heart rate,BMI,and fasting glucose were independent determinants of BaPWV. Conclusions The presence of an increasing number of MeS risk factors is

  4. Relationship between vascular endothelial function and pulse wave velocity in prehypertension

    Institute of Scientific and Technical Information of China (English)

    杨娉婷

    2014-01-01

    Objective To investigate the association between vascular endothelial function and arteriosclerosis in prehypertensive,hypertensive and healthy subjects.Methods 810 consecutive subjects were divided into three groups:hypertension group,prehypertension group and control group.Brachial-ankle pulse wave velocity(ba PWV)and flow-mediated brachial artery dilation(FMD)were used to evaluate the artery vascular stiffness and endothelial function respectively.Results Prehypertension

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

    Institute of Scientific and Technical Information of China (English)

    DENG Xin Ru; BI Yu Fang; LU Jie Li; ZHANG Yin Fei; WANG Tian Ge; XU Bai Hui; SUN Ji Chao; ZHAO Lie Bin; XU Min; CHEN Yu Hong; WANG Wei Qing

    2014-01-01

    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 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.

  6. Relationship between resistant hypertension and arterial stiffness assessed by brachial-ankle pulse wave velocity in the older patient

    OpenAIRE

    Chung CM; Cheng HW; Chang JJ; Lin YS; Hsiao JF; Chang ST; Hsu JT

    2014-01-01

    Chang-Min Chung,1,2 Hui-Wen Cheng,2 Jung-Jung Chang,2 Yu-Sheng Lin,2 Ju-Feng Hsiao,2 Shih-Tai Chang,1 Jen-Te Hsu2,31School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, 2Division of Cardiology, Chang Gung Memorial Hospital, Chiayi, 3Department of Medicine, College of Medicine, Chang Gung University, Taoyuan County, TaiwanBackground: Resistant hypertension (RH) is a common clinical condition associated with increased cardiovascular mortality and morbidi...

  7. Relationship between resistant hypertension and arterial stiffness assessed by brachial-ankle pulse wave velocity in the older patient

    OpenAIRE

    Chung, Chang-Min

    2014-01-01

    Chang-Min Chung,1,2 Hui-Wen Cheng,2 Jung-Jung Chang,2 Yu-Sheng Lin,2 Ju-Feng Hsiao,2 Shih-Tai Chang,1 Jen-Te Hsu2,31School of Traditional Chinese Medicine, College of Medicine, Chang Gung University, 2Division of Cardiology, Chang Gung Memorial Hospital, Chiayi, 3Department of Medicine, College of Medicine, Chang Gung University, Taoyuan County, TaiwanBackground: Resistant hypertension (RH) is a common clinical condition associated with increased cardiovascular mortality and...

  8. Validity and reproducibility of arterial pulse wave velocity measurement using new device with oscillometric technique: A pilot study

    Directory of Open Access Journals (Sweden)

    Patnaik Amar

    2005-08-01

    Full Text Available Abstract Background Availability of a range of techniques and devices allow measurement of many variables related to the stiffness of large or medium sized arteries. There is good evidence that, pulse wave velocity is a relatively simple measurement and is a good indicator of changes in arterial properties. The pulse wave velocity calculated from pulse wave recording by other methods like doppler or tonometry is tedious, time-consuming and above all their reproducibility depends on the operator skills. It requires intensive resource involvement. For epidemiological studies these methods are not suitable. The aim of our study was to clinically evaluate the validity and reproducibility of a new automatic device for measurement of pulse wave velocity that can be used in such studies. Methods In 44 subjects including normal healthy control and patients with coronary artery disease, heart brachial, heart ankle, brachial ankle and carotid femoral pulse wave velocities were recorded by using a new oscillometric device. Lead I and II electrocardiogram and pressure curves were simultaneously recorded. Two observers recorded the pulse wave velocity for validation and one observer recorded the velocity on two occasions for reproducibility. Results and Discussion Pulse wave velocity and arterial stiffness index were recorded in 24 control and 20 coronary artery disease patients. All the velocities were significantly high in coronary artery disease patients. There was highly significant correlation between the values noted by the two observers with low standard deviation. The Pearson's correlation coefficient for various velocities ranged from (r = 0.88–0.90 with (p Conclusion The new device "PeriScope" based on oscillometric technique has been found to be a simple, non-invasive and reproducible device for the assessment of pulse wave velocity and can be used to determine arterial stiffness in large population based studies.

  9. Sequentially pulsed traveling wave accelerator

    Science.gov (United States)

    Caporaso, George J.; Nelson, Scott D.; Poole, Brian R.

    2009-08-18

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  10. Wave equations for pulse propagation

    Science.gov (United States)

    Shore, B. W.

    1987-06-01

    Theoretical discussions of the propagation of pulses of laser radiation through atomic or molecular vapor rely on a number of traditional approximations for idealizing the radiation and the molecules, and for quantifying their mutual interaction by various equations of propagation (for the radiation) and excitation (for the molecules). In treating short-pulse phenomena it is essential to consider coherent excitation phenomena of the sort that is manifest in Rabi oscillations of atomic or molecular populations. Such processes are not adequately treated by rate equations for excitation nor by rate equations for radiation. As part of a more comprehensive treatment of the coupled equations that describe propagation of short pulses, this memo presents background discussion of the equations that describe the field. This memo discusses the origin, in Maxwell's equations, of the wave equation used in the description of pulse propagation. It notes the separation into lamellar and solenoidal (or longitudinal and transverse) and positive and negative frequency parts. It mentions the possibility of separating the polarization field into linear and nonlinear parts, in order to define a susceptibility or index of refraction and, from these, a phase and group velocity.

  11. Jittering waves in rings of pulse oscillators.

    Science.gov (United States)

    Klinshov, Vladimir; Shchapin, Dmitry; Yanchuk, Serhiy; Nekorkin, Vladimir

    2016-07-01

    Rings of oscillators with delayed pulse coupling are studied analytically, numerically, and experimentally. The basic regimes observed in such rings are rotating waves with constant interspike intervals and phase lags between the neighbors. We show that these rotating waves may destabilize leading to the so-called jittering waves. For these regimes, the interspike intervals are no more equal but form a periodic sequence in time. Analytic criterion for the emergence of jittering waves is derived and confirmed by the numerical and experimental data. The obtained results contribute to the hypothesis that the multijitter instability is universal in systems with pulse coupling. PMID:27575122

  12. Quarter-wave pulse tube

    Science.gov (United States)

    Swift, G. W.; Gardner, D. L.; Backhaus, S. N.

    2011-10-01

    In high-power pulse-tube refrigerators, the pulse tube itself can be very long without too much dissipation of acoustic power on its walls. The pressure amplitude, the volume-flow-rate amplitude, and the time phase between them evolve significantly along a pulse tube that is about a quarter-wavelength long. Proper choice of length and area makes the oscillations at the ambient end of the long pulse tube optimal for driving a second, smaller pulse-tube refrigerator, thereby utilizing the acoustic power that would typically have been dissipated in the first pulse-tube refrigerator's orifice. Experiments show that little heat is carried from the ambient heat exchanger to the cold heat exchanger in such a long pulse tube, even though the oscillations are turbulent and even when the tube is compactly coiled.

  13. Supratentorial pressures. Part II: Intracerebral pulse waves.

    Science.gov (United States)

    Miller, J D; Peeler, D F; Pattisapu, J; Parent, A D

    1987-09-01

    Intracerebral pulse waves were recorded in cat and monkey while intracranial pressure (ICP) manipulations were performed. The intracerebral pulse waves appeared comparable to cerebrospinal fluid (CSF) pulsations. The wave forms were divided into multiple smaller waves, designated P1 to P4. The P1 component was primarily of arterial origin and was accentuated by increasing ICP unrelated to increased venous pressure, most commonly from a mass lesion. Bilateral carotid occlusion resulted in decreased amplitude of P1. Venous hypertension from jugular venous or sagittal sinus occlusion, on the other hand, accentuated waves P2 and P3 more than P1. This is consistent with a Starling resistor model of the cerebral venous system in which mass lesions may compress low-pressure veins and accentuate the arterial pressure-dependent P1 wave, whereas venous hypertension causes increased prominence of the later P2 and P3 waves. PMID:2891069

  14. Pulse Wave Propagation in the Arterial Tree

    Science.gov (United States)

    van de Vosse, Frans N.; Stergiopulos, Nikos

    2011-01-01

    The beating heart creates blood pressure and flow pulsations that propagate as waves through the arterial tree that are reflected at transitions in arterial geometry and elasticity. Waves carry information about the matter in which they propagate. Therefore, modeling of arterial wave propagation extends our knowledge about the functioning of the cardiovascular system and provides a means to diagnose disorders and predict the outcome of medical interventions. In this review we focus on the physical and mathematical modeling of pulse wave propagation, based on general fluid dynamical principles. In addition we present potential applications in cardiovascular research and clinical practice. Models of short- and long-term adaptation of the arterial system and methods that deal with uncertainties in personalized model parameters and boundary conditions are briefly discussed, as they are believed to be major topics for further study and will boost the significance of arterial pulse wave modeling even more.

  15. Pulse Wave Velocity in the Carotid Artery

    DEFF Research Database (Denmark)

    Sørensen, Gertrud Laura; Jensen, Julie Brinck; Udesen, Jesper;

    2008-01-01

    The pulse wave velocity (PWV) in the carotid artery (CA) has been estimated based on ultrasound data collected by the experimental scanner RASMUS at DTU. Data is collected from one test subject using a frame rate (FR) of 4000 Hz. The influence of FRs is also investigated. The PWV is calculated from...... distension wave forms (DWF) estimated using cross-correlation. The obtained velocities give results in the area between 3-4 m/s, and the deviations between estimated PWV from two beats of a pulse are around 10%. The results indicate that the method presented is applicable for detecting the local PWV...

  16. Landau damping of a driven plasma wave from laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Bu Zhigang [Department of Physics, Shanghai University, Shanghai 200444 (China); Ji Peiyong [Department of Physics, Shanghai University, Shanghai 200444 (China); The Shanghai Key Lab of Astrophysics, Shanghai 200234 (China)

    2012-01-15

    The interaction between a laser pulse and a driven plasma wave with a phase velocity approaching the speed of light is studied, and our investigation is focused on the Gaussian laser pulse. It is demonstrated that when the resonance condition between the plasma wave and the laser pulse is satisfied, the Landau damping phenomenon of the plasma wave originated from the laser pulse will emerge. The dispersion relations for the plasma waves in resonance and non-resonance regions are obtained. It is proved that the Landau damping rate for a driven plasma wave is {gamma}>0 in the resonance region, so the laser pulse can produce an inverse damping effect, namely Landau growth effect, which leads an instability for the plasma wave. The Landau growth means that the energy is transmitted from the laser pulse to the plasma wave, which could be an effective process for enhancing the plasma wave.

  17. EMD-based Adaptive Wavelet Threshold for Pulse Wave Denoising

    Institute of Scientific and Technical Information of China (English)

    XU Li-shengl; SHEN Yan-hua; ZHONG Yue; KANG Yan; Max Q-H Meng

    2015-01-01

    It is inevitable that noises will be introduced during the acquisition of pulse wave signal, which can result in morphology changes of the original pulse wave, and affect the hemodynamic analysis and diagnosis based on pulse wave signalsIn order to remove these noises, an adaptive de-noising method based on empirical mode decomposition (EMD) and wavelet threshold is proposed in this paperCompared with the wavelet threshold method for denoising pulse wave, the proposed approach is more effective, especially at low signal-to-noise ratio.

  18. Resonant dispersive waves generated with multi-input femtosecond pulses

    Science.gov (United States)

    Wang, Kai; Peng, Jiahui; Sokolov, Alex

    2010-10-01

    We investigated the resonant dispersive waves generated by high-order dispersion theoretically. We considered different femtosecond pulses propagating in the kagome-lattice hollow-core photonics crystal fibers. The two third order and fourth order resonant dispersive waves would be produced in the visible range to produce the ultrashort pulse.

  19. Aortic pulse wave velocity improves cardiovascular event prediction

    DEFF Research Database (Denmark)

    Ben-Shlomo, Yoav; Spears, Melissa; Boustred, Chris;

    2014-01-01

    To determine whether aortic pulse wave velocity (aPWV) improves prediction of cardiovascular (CVD) events beyond conventional risk factors.......To determine whether aortic pulse wave velocity (aPWV) improves prediction of cardiovascular (CVD) events beyond conventional risk factors....

  20. Reproducibility of Regional Pulse Wave Velocity in Healthy Subjects

    OpenAIRE

    Lee, Nak Bum; Park, Chang Gyu

    2009-01-01

    Background/Aims Despite the clinical importance and widespread use of pulse wave velocity (PWV), there are no standards for pulse sensors or for system requirements to ensure accurate pulse wave measurement. We assessed the reproducibility of PWV values using a newly developed PWV measurement system. Methods The system used in this study was the PP-1000, which simultaneously provides regional PWV values from arteries at four different sites (carotid, femoral, radial, and dorsalis pedis). Seve...

  1. BIOLOGICAL EFFECTS OF PULSED SHORT WAVE TREATMENT. AN EXPERIMENTAL STUDY

    OpenAIRE

    Dogaru Gabriela; Crăciun Constantin

    2015-01-01

    Pulsed short waves are short electromagnetic waves emitted as intermittent trains with a fixed duration, separated by free intervals of variable duration. The biological effects of pulsed short waves could be explained according to most of the authors by an activation of cellular enzymatic reactions, a stimulation of energy metabolism, a stimulation of liver function, of adrenal gland function and of the reticulocyte system, changes in cell permeability, by an increase of peripheral blood flo...

  2. Holes and chaotic pulses of traveling waves coupled to a long-wave mode

    CERN Document Server

    Herrero, H; Herrero, Henar; Riecke, Hermann

    1997-01-01

    Localized traveling-wave pulses and holes, i.e. localized regions of vanishing wave amplitude, are investigated in a real Ginzburg-Landau equation coupled to a long-wave mode. In certain parameter regimes the pulses exhibit a Hopf bifurcation which leads to a breathing motion. Subsequently the oscillations undergo period-doubling bifurcations and become chaotic.

  3. Increasing pulse wave velocity in a realistic cardiovascular model does not increase pulse pressure with age

    OpenAIRE

    Mohiuddin, Mohammad W.; Rihani, Ryan J.; Laine, Glen A.; Quick, Christopher M.

    2012-01-01

    The mechanism of the well-documented increase in aortic pulse pressure (PP) with age is disputed. Investigators assuming a classical windkessel model believe that increases in PP arise from decreases in total arterial compliance (Ctot) and increases in total peripheral resistance (Rtot) with age. Investigators assuming a more sophisticated pulse transmission model believe PP rises because increases in pulse wave velocity (cph) make the reflected pressure wave arrive earlier, augmenting systol...

  4. Accuracy of Arterial Pulse-Wave Velocity Measurement Using MR

    OpenAIRE

    Bolster, Bradley D.; Atalar, Ergin; Hardy, Christopher J.; McVeigh, Elliot R.

    1998-01-01

    The performance of a one-dimensional MR technique for the estimation of pulse-wave velocity in the aorta was evaluated. An expression for the error in this estimate was formulated and verified both by simulation and by experiment. On the basis of this formulation, guidelines for increasing the efficiency of the acquisition were established. The technique was further validated by comparison with pulse-wave velocity measurements made with a pressure catheter. All data were acquired from a latex...

  5. Numerical continuation of travelling waves and pulses in neural fields

    OpenAIRE

    Meijer, Hil G.E.; Coombes, Stephen

    2013-01-01

    We study travelling waves and pulses in neural fields. Neural fields are a macroscopic description of the activity of brain tissue, which mathematically are formulated as integro-differential equations. While linear and weakly nonlinear analysis can describe instabilities and small amplitude patterns, numerical techniques are needed to study the nonlinear properties of travelling waves and pulses. Here we report on progress of such an approach using an excitatory neural field with linear adap...

  6. High-power pulse trains excited by modulated continuous waves

    OpenAIRE

    Wang, Yan; Song, Lijun; Li, Lu; Malomed, Boris A.

    2015-01-01

    Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demo...

  7. Holes and chaotic pulses of traveling waves coupled to a long-wave mode

    Science.gov (United States)

    Herrero, Henar; Riecke, Hermann

    1997-02-01

    It is shown that localized traveling-wave pulses and holes can be stabilized by a coupling to a long-wave mode. Simulations of suitable real Ginzburg-Landau equations reveal a small parameter regime in which the pulses exhibit a breathing motion (presumably related to a front bifurcation), which subsequently becomes chaotic via period-doubling bifurcations.

  8. Traveling waves of the regularized short pulse equation

    International Nuclear Information System (INIS)

    The properties of the so-called regularized short pulse equation (RSPE) are explored with a particular focus on the traveling wave solutions of this model. We theoretically analyze and numerically evolve two sets of such solutions. First, using a fixed point iteration scheme, we numerically integrate the equation to find solitary waves. It is found that these solutions are well approximated by a finite sum of hyperbolic secants powers. The dependence of the soliton's parameters (height, width, etc) to the parameters of the equation is also investigated. Second, by developing a multiple scale reduction of the RSPE to the nonlinear Schrödinger equation, we are able to construct (both standing and traveling) envelope wave breather type solutions of the former, based on the solitary wave structures of the latter. Both the regular and the breathing traveling wave solutions identified are found to be robust and should thus be amenable to observations in the form of few optical cycle pulses. (paper)

  9. Pulse based sensor networking using mechanical waves through metal substrates

    Science.gov (United States)

    Lorenz, S.; Dong, B.; Huo, Q.; Tomlinson, W. J.; Biswas, S.

    2013-05-01

    This paper presents a novel wireless sensor networking technique using ultrasonic signal as the carrier wave for binary data exchange. Using the properties of lamb wave propagation through metal substrates, the proposed network structure can be used for runtime transport of structural fault information to ultrasound access points. Primary applications of the proposed sensor networking technique will include conveying fault information on an aircraft wing or on a bridge to an ultrasonic access point using ultrasonic wave through the structure itself (i.e. wing or bridge). Once a fault event has been detected, a mechanical pulse is forwarded to the access node using shortest path multi-hop ultrasonic pulse routing. The advantages of mechanical waves over traditional radio transmission using pulses are the following: First, unlike radio frequency, surface acoustic waves are not detectable outside the medium, which increases the inherent security for sensitive environments in respect to tapping. Second, event detection can be represented by the injection of a single mechanical pulse at a specific temporal position, whereas radio messages usually take several bits. The contributions of this paper are: 1) Development of a transceiver for transmitting/receiving ultrasound pulses with a pulse loss rate below 2·10-5 and false positive rate with an upper bound of 2·10-4. 2) A novel one-hop distance estimation based on the properties of lamb wave propagation with an accuracy of above 80%. 3) Implementation of a wireless sensor network using mechanical wave propagation for event detection on a 2024 aluminum alloy commonly used for aircraft skin construction.

  10. Four-wave mixing in nanosecond pulsed fiber amplifiers.

    Science.gov (United States)

    Fève, Jean-Philippe; Schrader, Paul E; Farrow, Roger L; Kliner, Dahv A V

    2007-04-16

    We present an experimental and theoretical analysis of four-wave mixing in nanosecond pulsed amplifiers based on double-clad ytterbium-doped fibers. This process leads to saturation of the amplified pulse energy at 1064 nm and to distortion of the spectral and temporal profiles. These behaviours are well described by a simple model considering both Raman and four-wave-mixing contributions. The role of seed laser polarization in birefringent fibers is also presented. These results point out the critical parameters and possible tradeoffs for optimization. PMID:19532710

  11. High-power pulse trains excited by modulated continuous waves

    CERN Document Server

    Wang, Yan; Li, Lu; Malomed, Boris A

    2015-01-01

    Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demonstrated that the double trains propagate in a robust form, with frequencies shifted by the Raman effect.

  12. Cardioaccelerometery: the assessment of pulse wave velocity using accelerometers

    OpenAIRE

    Pereira, Helena Catarina de Bastos Marques

    2007-01-01

    In the past recent years, great emphasis has been placed on the role of arterial stiffness in the development of cardiovascular diseases, recognized as the leading cause of death in the world. This hemodynamic parameter, generally associated to age and blood pressure increase, can be assessed by the measurement of the pulse wave velocity (PWV), i.e., the velocity at which the pressure wave propagates along an artery. Although PWV measurement is accepted as the most simple, non-...

  13. Limited Diffraction Maps for Pulsed Wave Annular Arrays

    DEFF Research Database (Denmark)

    Fox, Paul D.

    2002-01-01

    A procedure is provided for decomposing the linear field of flat pulsed wave annular arrays into an equivalent set of known limited diffraction Bessel beams. Each Bessel beam propagates with known characteristics, enabling good insight into the propagation of annular fields to be obtained...

  14. Difficulties in the measurement of pulse-wave velocity

    NARCIS (Netherlands)

    Klip, W.

    1958-01-01

    The methods employed in the measuring of pulse-wave velocity are subject to gross error because of alinearity and frequency distortion resulting from low-resonance frequencies of instrumentation and arterial segment and extraneous tissue interference. Deformation also occurs because of different spe

  15. Non-invasive measurement of local pulse pressure by pulse wave-based ultrasound manometry (PWUM)

    OpenAIRE

    Vappou, J.; Luo, J; Okajima, K.; Di Tullio, M; Konofagou, E E

    2011-01-01

    The central Blood Pressure (CBP) has been established as a relevant indicator of cardiovascular disease. Despite its significance, CBP remains particularly challenging to measure in standard clinical practice. The objective of this study is to introduce Pulse Wave-based Ultrasound Manometry (PWUM) as a simple-touse, non-invasive ultrasound-based method for quantitative measurement of the central pulse pressure. Arterial wall displacements are estimated using radiofrequency (RF) ultrasound sig...

  16. Noninvasive continuous monitoring of digital pulse waves during hemodialysis

    DEFF Research Database (Denmark)

    Burkert, Antje; Scholze, Alexandra; Tepel, Martin

    2009-01-01

    , investigator-independent, automatic analysis of digital volume pulse in 10 healthy subjects and in 20 patients with end-stage renal failure during the hemodialysis session. The reflective index was defined representing the diastolic component of the digital pulse wave. The properties of the reflective index......Intermittent hemodynamic instability during hemodialysis treatment is a frequent complication in patients with end-stage renal failure. A noninvasive method for continuous hemodynamic monitoring is needed. We used noninvasive digital photoplethysmography and an algorithm for continuous...... were studied in healthy control subjects (n=10). An increased reflective index was due to increased peripheral pulse wave reflection (e.g., vasoconstriction). During a hemodialysis session, the reflective index increased significantly from 36+/-3 arbitrary units to 41+/-3 arbitrary units (n=20; p...

  17. l-Citrulline supplementation attenuates blood pressure, wave reflection and arterial stiffness responses to metaboreflex and cold stress in overweight men.

    Science.gov (United States)

    Figueroa, Arturo; Alvarez-Alvarado, Stacey; Jaime, Salvador J; Kalfon, Roy

    2016-07-01

    Combined isometric exercise or metaboreflex activation (post-exercise muscle ischaemia (PEMI)) and cold pressor test (CPT) increase cardiac afterload, which may lead to adverse cardiovascular events. l-Citrulline supplementation (l-CIT) reduces systemic arterial stiffness (brachial-ankle pulse wave velocity (baPWV)) at rest and aortic haemodynamic responses to CPT. The aim of this study was to determine the effect of l-CIT on aortic haemodynamic and baPWV responses to PEMI+CPT. In all, sixteen healthy, overweight/obese males (age 24 (sem 6) years; BMI 29·3 (sem 4·0) kg/m2) were randomly assigned to placebo or l-CIT (6 g/d) for 14 d in a cross-over design. Brachial and aortic systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP), aortic augmented pressure (AP), augmentation index (AIx), baPWV, reflection timing (Tr) and heart rate (HR) were evaluated at rest and during isometric handgrip exercise (IHG), PEMI and PEMI+CPT at baseline and after 14 d. No significant effects were evident after l-CIT at rest. l-CIT attenuated the increases in aortic SBP and wave reflection (AP and AIx) during IHG, aortic DBP, MAP and AIx during PEMI, and aortic SBP, DBP, MAP, AP, AIx and baPWV during PEMI+CPT compared with placebo. HR and Tr were unaffected by l-CIT in all conditions. Our findings demonstrate that l-CIT attenuates aortic blood pressure and wave reflection responses to exercise-related metabolites. Moreover, l-CIT attenuates the exaggerated arterial stiffness response to combined metaboreflex activation and cold exposure, suggesting a protective effect against increased cardiac afterload during physical stress. PMID:27160957

  18. Rydberg Wave Packets and Half-Cycle Electromagnetic Pulses

    Science.gov (United States)

    Raman, Chandra S.

    1998-05-01

    This dissertation summarizes an examination of the dynamics of atomic Rydberg wave packets with coherent pulses of THz electromagnetic radiation consisting of less than a single cycle of the electric field. The bulk of the energy is contained in just a half-cycle. Previous work ( R. Jones, D. You, and P. Bucksbaum, ``Ionization of Rydberg atoms by subpicosecond half-cycle electromagnetic pulses,'' Phys. Rev. Lett.), vol. 70, 1993. had shown how these half-cycle pulses can be used to ionize the highly excited states of an atom, and that a classical view of electronic motion in the atom explains the ionization mechanism. To further probe the boundary between classical trajectories and quantum mechanics, in this work I investigate dynamical combinations of Rydberg states, or Rydberg wave packets, and how they ionize under the influence of a half-cycle electromagnetic pulse. With time-domain techniques I am able to extract the dynamics of the wave packet from the ionization rate, and to observe wave packet motion in both the electronic radial ( C. Raman, C. Conover, C. Sukenik, and P. Bucksbaum, ``Ionization of Rydberg wavepackets by sub-picosecond half-cycle electromagnetic pulses,'' Phys. Rev. Lett.), vol. 76, 1996.and angular ( C. Raman, T. Weinacht, and P. Bucksbaum, ``Stark wavepackets viewed with half cycle pulses.'' Phys. Rev. A), vol. 55, No. 6, 1997. coordinates. This is the first time a wavepacket technique has been used to view electron motion everywhere on its trajectory, and not just at the nucleus. This is the principal feature of half-cycle pulse ionization. Semiclassical ideas of ionization in conjunction with quantum descriptions of the wave packet, are capable of reproducing the main trends in the data, and in the absence of a rigorous model I rely on these. Experiments of this nature provide examples of the ongoing effort to use the coherent properties of radiation to control electronic motion in an atom, as well as to probe the boundaries between

  19. Toroidal Imploding Detonation Wave Initiator for Pulse Detonation Engines

    OpenAIRE

    Jackson, S. I.; Shepherd, J. E.

    2007-01-01

    Imploding toroidal detonation waves were used to initiate detonations in propane–air and ethylene–air mixtures inside of a tube. The imploding wave was generated by an initiator consisting of an array of channels filled with acetylene–oxygen gas and ignited with a single spark. The initiator was designed as a low-drag initiator tube for use with pulse detonation engines. To detonate hydrocarbon–air mixtures, the initiator was overfilled so that some acetylene oxygen spilled into the tube. The...

  20. Flexible pulse-wave sensors from oriented aluminum nitride nanocolumns

    Science.gov (United States)

    Akiyama, Morito; Ueno, Naohiro; Nonaka, Kazuhiro; Tateyama, Hiroshi

    2003-03-01

    Flexible pulse-wave sensors were fabricated from density-packed oriented aluminum nitride nanocolumns prepared on aluminum foils. The nanocolumns were prepared by the rf magnetron sputtering method and were perpendicularly oriented to the aluminum foil surfaces. The sensor structure is laminated, and the structure contributes to avoiding unexpected leakage of an electric charge. The resulting sensor thickness is 50 μm. The sensor is flexible like aluminum foil and can respond to frequencies from 0.1 to over 100 Hz. The sensitivity of the sensor to pressure is proportional to the surface area. The sensor sensitively causes reversible charge signals that correlate with the pulse wave form, which contains significant information on arteriosclerosis and cardiopathy of a man sitting on it.

  1. Non-invasive measurement of local pulse pressure by pulse wave-based ultrasound manometry (PWUM)

    International Nuclear Information System (INIS)

    Central blood pressure (CBP) has been established as a relevant indicator of cardiovascular disease. Despite its significance, CBP remains particularly challenging to measure in standard clinical practice. The objective of this study is to introduce pulse wave-based ultrasound manometry (PWUM) as a simple-to-use, non-invasive ultrasound-based method for quantitative measurement of the central pulse pressure. Arterial wall displacements are estimated using radiofrequency ultrasound signals acquired at high frame rates and the pulse pressure waveform is estimated using both the distension waveform and the local pulse wave velocity. The method was tested on the abdominal aorta of 11 healthy subjects (age 35.7±16 y.o.). PWUM pulse pressure measurements were compared to those obtained by radial applanation tonometry using a commercial system. The average intra-subject variability of the pulse pressure amplitude was found to be equal to 4.2 mmHg, demonstrating good reproducibility of the method. Excellent correlation was found between the waveforms obtained by PWUM and those obtained by tonometry in all subjects (0.94 < r < 0.98). A significant bias of 4.7 mmHg was found between PWUM and tonometry. PWUM is a highly translational method that can be easily integrated in clinical ultrasound imaging systems. It provides an estimate of the pulse pressure waveform at the imaged location, and may offer therefore the possibility to estimate the pulse pressure at different arterial sites. Future developments include the validation of the method against invasive estimates on patients, as well as its application to other large arteries

  2. Femtosecond-pulse-train ionization of Rydberg wave packets

    OpenAIRE

    Simonsen, Sigrid Ina; Sørngård, Stian Astad; Førre, Morten; Hansen, Jan Petter

    2012-01-01

    We calculate, based on first-order perturbation theory, the total and differential ionization probabilities from a dynamic periodic Rydberg wave packet of a given n-shell exposed to a train of femtosecond laser pulses. The total probability is shown to depend crucially on the laser repetition rate: For certain frequencies the ionization probability vanishes, while for others it becomes very large. The origin of this effect is the strong dependence of the ionization probability on ...

  3. A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

    International Nuclear Information System (INIS)

    We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2∼1.0μW in the Human heart rate range on the skin contact area of 3.71cm2. Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves

  4. Increasing pulse wave velocity in a realistic cardiovascular model does not increase pulse pressure with age.

    Science.gov (United States)

    Mohiuddin, Mohammad W; Rihani, Ryan J; Laine, Glen A; Quick, Christopher M

    2012-07-01

    The mechanism of the well-documented increase in aortic pulse pressure (PP) with age is disputed. Investigators assuming a classical windkessel model believe that increases in PP arise from decreases in total arterial compliance (C(tot)) and increases in total peripheral resistance (R(tot)) with age. Investigators assuming a more sophisticated pulse transmission model believe PP rises because increases in pulse wave velocity (c(ph)) make the reflected pressure wave arrive earlier, augmenting systolic pressure. It has recently been shown, however, that increases in c(ph) do not have a commensurate effect on the timing of the reflected wave. We therefore used a validated, large-scale, human arterial system model that includes realistic pulse wave transmission to determine whether increases in c(ph) cause increased PP with age. First, we made the realistic arterial system model age dependent by altering cardiac output (CO), R(tot), C(tot), and c(ph) to mimic the reported changes in these parameters from age 30 to 70. Then, c(ph) was theoretically maintained constant, while C(tot), R(tot), and CO were altered. The predicted increase in PP with age was similar to the observed increase in PP. In a complementary approach, C(tot), R(tot), and CO were theoretically maintained constant, and c(ph) was increased. The predicted increase in PP was negligible. We found that increases in c(ph) have a limited effect on the timing of the reflected wave but cause the system to degenerate into a windkessel. Changes in PP can therefore be attributed to a decrease in C(tot). PMID:22561301

  5. Quantum-state-preserving optical frequency conversion and pulse reshaping by four-wave mixing

    DEFF Research Database (Denmark)

    McKinstrie, C. J.; Andersen, Lasse Mejling; Raymer, M. G.;

    2012-01-01

    Nondegenerate four-wave mixing driven by two pulsed pumps transfers the quantum state of an input signal pulse to an output idler pulse, which is a frequency-converted and reshaped version of the signal. By varying the pump shapes appropriately, one can connect signal and idler pulses with arbitr......Nondegenerate four-wave mixing driven by two pulsed pumps transfers the quantum state of an input signal pulse to an output idler pulse, which is a frequency-converted and reshaped version of the signal. By varying the pump shapes appropriately, one can connect signal and idler pulses...

  6. BIOLOGICAL EFFECTS OF PULSED SHORT WAVE TREATMENT. AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    Dogaru Gabriela

    2015-02-01

    Full Text Available Pulsed short waves are short electromagnetic waves emitted as intermittent trains with a fixed duration, separated by free intervals of variable duration. The biological effects of pulsed short waves could be explained according to most of the authors by an activation of cellular enzymatic reactions, a stimulation of energy metabolism, a stimulation of liver function, of adrenal gland function and of the reticulocyte system, changes in cell permeability, by an increase of peripheral blood flow through the enhancement of local vascularization. This research aimed to investigate the biological effects of exposure to pulsed short waves at different doses on the adrenal glands of experimental animals, by structural and ultrastructural studies. The study included 35 animals assigned to 4 groups. Group I included 10 experimental animals exposed to radiation at a dose of 1/80 impulses/sec, group II, 10 animals exposed to a dose of 4/400 impulses/sec, group III, 10 animals exposed to a dose of 6/600 impulses/sec, for 10 min/day, and the control group consisted of 5 unexposed animals. Structural and ultrastructural changes of adrenal glands induced by the dose of 4/400 impulses/sec, compared to the unexposed control group and the dose of 1/80 impulses/sec, include an intensification of protein synthesis processes, an enhancement of energy metabolism in providing the energy required for an increased production of hormones, an intensification of collagen fiber synthesis processes in the capsule, necessary for healing. It was demonstrated that this dose induced an intensification of hormone synthesis and secretion, a stimulation of adrenal function. At the dose of 6/600 cycles/sec, a slight diminution of hormone synthesis and secretion activity was found, which was not below the limits existing in the unexposed control group, but was comparable to group II. This dose is probably too strong for experimental animals, inducing them a state of stress. The

  7. Three-wave mixing mediated femtosecond pulse compression in β-barium borate.

    Science.gov (United States)

    Grün, A; Austin, Dane R; Cousin, Seth L; Biegert, J

    2015-10-15

    Nonlinear pulse compression mediated by three-wave mixing is demonstrated for ultrashort Ti:sapphire pulses in a type II phase-matched β-barium borate (BBO) crystal using noncollinear geometry. 170 μJ pulses at 800 nm with a pulse duration of 74 fs are compressed at their sum frequency to 32 fs with 55 μJ of pulse energy. Experiments and computer simulations demonstrate the potential of sum-frequency pulse compression to match the group velocities of the interacting waves to crystals that were initially not considered in the context of nonlinear pulse compression.

  8. Three-wave mixing mediated femtosecond pulse compression in β-barium borate.

    Science.gov (United States)

    Grün, A; Austin, Dane R; Cousin, Seth L; Biegert, J

    2015-10-15

    Nonlinear pulse compression mediated by three-wave mixing is demonstrated for ultrashort Ti:sapphire pulses in a type II phase-matched β-barium borate (BBO) crystal using noncollinear geometry. 170 μJ pulses at 800 nm with a pulse duration of 74 fs are compressed at their sum frequency to 32 fs with 55 μJ of pulse energy. Experiments and computer simulations demonstrate the potential of sum-frequency pulse compression to match the group velocities of the interacting waves to crystals that were initially not considered in the context of nonlinear pulse compression. PMID:26469593

  9. Estimation of Carotid Artery Pulse Wave Velocity by Doppler Ultrasonography

    OpenAIRE

    Mehdi Maerefat; Manijhe Mokhtari Dizaji; Saeed Rahgozar

    2009-01-01

    Background: Pulse wave velocity (PWV) is widely used for estimating the stiffness of an artery. Various invasive and non-invasive methods have been developed to determine PWV over the years. In the present research, the non-invasive estimation of the PWV of large arteries was used as an index for arterial stiffness. Methods: A dynamic model based on the Navier-Stokes equations coupled to elasticity equations was introduced for the PWV in arteries with elastic walls. This system of equations w...

  10. Weight Loss, Dietary Intake and Pulse Wave Velocity

    OpenAIRE

    Petersen, Kristina; Blanch, Natalie; Keogh, Jennifer; Clifton, Peter

    2015-01-01

    We have recently conducted a meta-analysis to determine the effect of weight loss achieved by an energy-restricted diet with or without exercise, anti-obesity drugs or bariatric surgery on pulse wave velocity (PWV) measured at all arterial segments. Twenty studies, including 1,259 participants, showed that modest weight loss (8% of the initial body weight) caused a reduction in PWV measured at all arterial segments. However, due to the poor methodological design of the included studies, the r...

  11. Detailed Characterization of Continuous-Wave and Pulsed-Pump Four-Wave Mixing in Nonlinear Fibers

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Galili, Michael; Grüner-Nielsen, Lars;

    2016-01-01

    We explore the parametric gain differences for continuous-wave and pulse-pumped four-wave mixing, using various highly nonlinear fibers. Detailed simulations support our findings that the dispersion slope determines the experimentally observed differences, limiting the pulsed-pump performance....

  12. Effect of Rectangle Wave Pulse Current on Solidification Structure of ZA27 Alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effect of rectangle wave pulse current on solidification structure of ZA27 alloy was studied.The results 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 clusters in melt, the oscillating state of melt on the surface of clusters, 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.

  13. Estimation of Arterial Stiffness by Time-Frequency Analysis of Pulse Wave

    Science.gov (United States)

    Saito, Masashi; Yamamoto, Yuya; Shibayama, Yuka; Matsukawa, Mami; Watanabe, Yoshiaki; Furuya, Mio; Asada, Takaaki

    2011-07-01

    Evaluation of a pulse wave is effective for the early diagnosis of arteriosclerosis because the pulse wave contains the reflected wave that is the age- and stiffness-dependent component. In this study, we attempted to extract the parameter reflecting the component by pulse wave analysis using continuous wavelet transform. The Morlet wavelet was used as the mother wavelet. We then investigated the relationship between the parameter and the reflected wave that was extracted from the pulse wave by our previously reported separation technique. Consequently, the result of wavelet transform of the differentiated pulse waveform changed markedly owing to age and had medium correlation with the peak of the reflected wave (R=0.68).

  14. Full-wave reflection of lightning long-wave radio pulses from the ionospheric D- region

    Science.gov (United States)

    Jacobson, A. R.; Shao, X.; Holzworth, R.

    2008-12-01

    A model is developed for calculating ionospheric reflection of electromagnetic pulses emitted by lightning, with most energy in the long-wave spectral region (f = 3 - 100 kHz). The building-block of the calculation is a differential-equation full-wave solution of Maxwell's Equations for the complex reflection of individual plane waves incident from below, by the anisotropic, dissipative, diffuse dielectric profile of the lower ionosphere. This full-wave solution is then put into a summation over plane waves in an angular Direct Fourier Transform to obtain the reflection properties of curved wavefronts. This step models also the diffraction effects of long- wave ionospheric reflections observed at short or medium range (200 - 500 km). The calculation can be done with any arbitrary but smooth dielectric profile versus altitude. For an initial test, we use the classic D- region exponential profiles of electron density and collision rate given by Wait. With even these simple profiles, our model of full-wave reflection of curved wavefronts captures some of the basic attributes of observed reflected waveforms recorded with the Los Alamos Sferic Array.

  15. Bit rate and pulse width dependence of four-wave mixing of short optical pulses in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Diez, S.; Mecozzi, A.; Mørk, Jesper

    1999-01-01

    We investigate the saturation properties of four-wave mixing of short optical pulses in a semiconductor optical amplifier. By varying the gain of the optical amplifier, we find a strong dependence of both conversion efficiency and signal-to-background ratio on pulse width and bit rate...

  16. Temporal pattern of pulse wave velocity during brachial hyperemia reactivity

    Science.gov (United States)

    Graf, S.; Valero, M. J.; Craiem, D.; Torrado, J.; Farro, I.; Zócalo, Y.; Valls, G.; Bía, D.; Armentano, R. L.

    2011-09-01

    Endothelial function can be assessed non-invasively with ultrasound, analyzing the change of brachial diameter in response to transient forearm ischemia. We propose a new technique based in the same principle, but analyzing a continuous recording of carotid-radial pulse wave velocity (PWV) instead of diameter. PWV was measured on 10 healthy subjects of 22±2 years before and after 5 minutes forearm occlusion. After 59 ± 31 seconds of cuff release PWV decreased 21 ± 9% compared to baseline, reestablishing the same after 533 ± 65 seconds. There were no significant changes observed in blood pressure. When repeating the study one hour later in 5 subjects, we obtained a coefficient of repeatability of 4.8%. In conclusion, through analysis of beat to beat carotid-radial PWV it was possible to characterize the temporal profiles and analyze the acute changes in response to a reactive hyperemia. The results show that the technique has a high sensitivity and repeatability.

  17. Application of wave-shape functions and Synchrosqueezing transform to pulse signal analysis

    CERN Document Server

    Wu, Hau-tieng; Wu, Han-Kuei; Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang

    2015-01-01

    We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and study the pulse wave signal. Based on the wave shape function model and SST, we extract features, called the spectral pulse signature, based on the functional regression technique, to characterize the hemodynamics from the pulse wave signals. To demonstrate how the algorithm and the extracted features work, we study the radial pulse wave signal recorded by the sphygmomanometer from normal subjects and patients with congestive heart failure. The analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features. In addition, it shows that different positions of the radial artery contain significant different information, which is compatible with the empirical conclusion of the pulse diagnosis in the traditional Chinese medicine.

  18. Focusing of Spherical Nonlinear Pulses for Nonlinear Wave Equations Ⅲ. Subcritical Case

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper studied spherical pulses of solutions of the system of semilinear wave equations with the pulses focusing at a point in three space variables. It is shown that there is no nonlinear effect at leading terms of pulses, when the initial data is subcritical.

  19. Noninvasive measurement of cardiac stroke volume using pulse wave velocity and aortic dimensions: a simulation study

    OpenAIRE

    Babbs, Charles F.

    2014-01-01

    Background: Concerns about the cost-effectiveness of invasive hemodynamic monitoring in critically ill patients using pulmonary artery catheters motivate a renewed search for effective noninvasive methods to measure stroke volume. This paper explores a new approach based on noninvasively measured pulse wave velocity, pulse contour, and ultrasonically determined aortic cross sectional area. Methods: The Bramwell-Hill equation relating pulse wave velocity to aortic compliance is applied. At the...

  20. Self-similar propagation of Hermite-Gauss water-wave pulses.

    Science.gov (United States)

    Fu, Shenhe; Tsur, Yuval; Zhou, Jianying; Shemer, Lev; Arie, Ady

    2016-01-01

    We demonstrate both theoretically and experimentally propagation dynamics of surface gravity water-wave pulses, having Hermite-Gauss envelopes. We show that these waves propagate self-similarly along an 18-m wave tank, preserving their general Hermite-Gauss envelopes in both the linear and the nonlinear regimes. The measured surface elevation wave groups enable observing the envelope phase evolution of both nonchirped and linearly frequency chirped Hermite-Gauss pulses, hence allowing us to measure Gouy phase shifts of high-order Hermite-Gauss pulses for the first time. Finally, when increasing pulse amplitude, nonlinearity becomes essential and the second harmonic of Hermite-Gauss waves was observed. We further show that these generated second harmonic bound waves still exhibit self-similar Hermite-Gauss shapes along the tank. PMID:26871174

  1. Pulse Wave Variation during the Menstrual Cycle in Women with Menstrual Pain.

    Science.gov (United States)

    Jeon, Soo Hyung; Kim, Kyu Kon; Lee, In Seon; Lee, Yong Tae; Kim, Gyeong Cheol; Chi, Gyoo Yong; Cho, Hye Sook; Kang, Hee Jung; Kim, Jong Won

    2016-01-01

    Objective. This study is performed to obtain objective diagnostic indicators associated with menstrual pain using pulse wave analysis. Methods. Using a pulse diagnostic device, we measured the pulse waves of 541 women aged between 19 and 30 years, placed in either an experimental group with menstrual pain (n = 329) or a control group with little or no menstrual pain (n = 212). Measurements were taken during both the menstrual and nonmenstrual periods, and comparative analysis was performed. Results. During the nonmenstrual period, the experimental group showed a significantly higher value in the left radial artery for the radial augmentation index (RAI) (p = 0.050) but significantly lower values for pulse wave energy (p = 0.021) and time to first peak from baseline (T1) (p = 0.035) in the right radial artery. During the menstrual period, the experimental group showed significantly lower values in the left radial artery for cardiac diastole and pulse wave area during diastole and significantly higher values for pulse wave area during systole, ratio of systolic phase to the full heartbeat, and systolic-diastolic ratio. Conclusion. We obtained indicators of menstrual pain in women during the menstrual period, including prolonged systolic and shortened diastolic phases, increases in pulse wave energy and area of representative pulse wave, and increased blood vessel resistance. PMID:27579304

  2. Pulse Wave Variation during the Menstrual Cycle in Women with Menstrual Pain

    Directory of Open Access Journals (Sweden)

    Soo Hyung Jeon

    2016-01-01

    Full Text Available Objective. This study is performed to obtain objective diagnostic indicators associated with menstrual pain using pulse wave analysis. Methods. Using a pulse diagnostic device, we measured the pulse waves of 541 women aged between 19 and 30 years, placed in either an experimental group with menstrual pain (n=329 or a control group with little or no menstrual pain (n=212. Measurements were taken during both the menstrual and nonmenstrual periods, and comparative analysis was performed. Results. During the nonmenstrual period, the experimental group showed a significantly higher value in the left radial artery for the radial augmentation index (RAI (p=0.050 but significantly lower values for pulse wave energy (p=0.021 and time to first peak from baseline (T1 (p=0.035 in the right radial artery. During the menstrual period, the experimental group showed significantly lower values in the left radial artery for cardiac diastole and pulse wave area during diastole and significantly higher values for pulse wave area during systole, ratio of systolic phase to the full heartbeat, and systolic-diastolic ratio. Conclusion. We obtained indicators of menstrual pain in women during the menstrual period, including prolonged systolic and shortened diastolic phases, increases in pulse wave energy and area of representative pulse wave, and increased blood vessel resistance.

  3. SOLITONS: Nonlinear dynamics of optical pulses in fibres with a travelling refractive-index-change wave

    Science.gov (United States)

    Adamova, M. S.; Zolotovskii, Igor'O.; Sementsov, Dmitrii I.

    2009-03-01

    Dynamics of soliton-like wave packets in fibres with a travelling refractive-index-change wave is studied. It is shown that both a soliton-like propagation regime of a pulse and a self-compression regime in the region of normal group velocity dispersion are possible. It is also shown that in the case of a copropagating or counterpropagating pulse and optically inhomogeneous wave nonreciprocal effects appear.

  4. MOSFET-based high voltage double square-wave pulse generator with an inductive adder configuration

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Qiaogen, E-mail: hvzhang@mail.xjtu.edu.cn [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); Long, Jinghua [College of Physics, Shenzhen University, Shenzhen 518060 (China); Lei, Yunfei; Liu, Jinyuan [Institute of Optoelectronics, Shenzhen University, Shenzhen 518060 (China)

    2015-09-01

    This paper presents a fast MOSFET-based solid-state pulse generator for high voltage double square-wave pulses. The generator consists mainly of an inductive adder system stacked of 20 solid-state modules. Each of the modules has 18 power MOSFETs in parallel, which are triggered by individual drive circuits; these drive circuits themselves are synchronously triggered by a signal from avalanche transistors. Our experiments demonstrate that the output pulses with amplitude of 8.1 kV and peak current of about 405 A are available at a load impedance of 20 Ω. The pulse has a double square-wave form with a rise and fall time of 40 ns and 26 ns, respectively and bottom flatness better than 12%. The interval time of the double square-wave pulses can be adjustable by varying the interval time of the trigger pulses.

  5. Weight Loss, Dietary Intake and Pulse Wave Velocity.

    Science.gov (United States)

    Petersen, Kristina; Blanch, Natalie; Keogh, Jennifer; Clifton, Peter

    2015-09-01

    We have recently conducted a meta-analysis to determine the effect of weight loss achieved by an energy-restricted diet with or without exercise, anti-obesity drugs or bariatric surgery on pulse wave velocity (PWV) measured at all arterial segments. Twenty studies, including 1,259 participants, showed that modest weight loss (8% of the initial body weight) caused a reduction in PWV measured at all arterial segments. However, due to the poor methodological design of the included studies, the results of this meta-analysis can only be regarded as hypothesis generating and highlight the need for further research in this area. In the future, well-designed randomised controlled trials are required to determine the effect of diet-induced weight loss on PWV and the mechanisms involved. In addition, there is observational evidence that dietary components such as fruit, vegetables, dairy foods, sodium, potassium and fatty acids may be associated with PWV, although evidence from well-designed intervention trials is lacking. In the future, the effect of concurrently improving dietary quality and achieving weight loss should be assessed in randomised controlled trials. PMID:26587462

  6. Estimation of Carotid Artery Pulse Wave Velocity by Doppler Ultrasonography

    Directory of Open Access Journals (Sweden)

    Mehdi Maerefat

    2009-06-01

    Full Text Available Background: Pulse wave velocity (PWV is widely used for estimating the stiffness of an artery. Various invasive and non-invasive methods have been developed to determine PWV over the years. In the present research, the non-invasive estimation of the PWV of large arteries was used as an index for arterial stiffness. Methods: A dynamic model based on the Navier-Stokes equations coupled to elasticity equations was introduced for the PWV in arteries with elastic walls. This system of equations was completed by clinical information obtained from the Doppler ultrasound images of the carotid artery of 40 healthy male volunteers. For this purpose, the Doppler ultrasound images were recorded and saved in a computer; and subsequently center-line blood velocity, arterial wall thickness, and arterial radius were measured by offline processing. Results: The results from the analytic solution of the completed equations showed that the mean value of PWV for the group of healthy volunteers was 2.35 m/s when the mean arterial radius was used as the neutral radius and 5.00 m/s when the end-diastole radius was used as the neutral radius. It is noteworthy that the latter value closely complies with that reported by other researchers. Conclusion: By applying this method, a non-invasive clinical and local evaluation of the common carotid artery stiffness via a Doppler ultrasound measurement will be possible.

  7. Underwater acoustic wave generation by filamentation of terawatt ultrashort laser pulses

    CERN Document Server

    Jukna, Vytautas; Milián, Carles; Brelet, Yohann; Carbonnel, Jérôme; André, Yves-Bernard; Guillermin, Régine; Sessarego, Jean-Pierre; Fattaccioli, Dominique; Mysyrowicz, André; Couairon, Arnaud; Houard, Aurélien

    2016-01-01

    Acoustic signals generated by filamentation of ultrashort TW laser pulses in water are characterized experimentally. Measurements reveal a strong influence of input pulse duration on the shape and intensity of the acoustic wave. Numerical simulations of the laser pulse nonlinear propagation and the subsequent water hydrodynamics and acoustic wave generation show that the strong acoustic emission is related to the mechanism of superfilamention in water. The elongated shape of the plasma volume where energy is deposited drives the far-field profile of the acoustic signal, which takes the form of a radially directed pressure wave with a single oscillation and a very broad spectrum.

  8. Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform.

    Directory of Open Access Journals (Sweden)

    Hau-Tieng Wu

    Full Text Available We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features.

  9. Modeling the Pulse Signal by Wave-Shape Function and Analyzing by Synchrosqueezing Transform

    Science.gov (United States)

    Wang, Chun-Li; Yang, Yueh-Lung; Wu, Wen-Hsiang; Tsai, Tung-Hu; Chang, Hen-Hong

    2016-01-01

    We apply the recently developed adaptive non-harmonic model based on the wave-shape function, as well as the time-frequency analysis tool called synchrosqueezing transform (SST) to model and analyze oscillatory physiological signals. To demonstrate how the model and algorithm work, we apply them to study the pulse wave signal. By extracting features called the spectral pulse signature, and based on functional regression, we characterize the hemodynamics from the radial pulse wave signals recorded by the sphygmomanometer. Analysis results suggest the potential of the proposed signal processing approach to extract health-related hemodynamics features. PMID:27304979

  10. Nonlinear pulse propagation and phase velocity of laser-driven plasma waves

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Carl B.; Benedetti, Carlo; Esarey, Eric; Leemans, Wim

    2011-03-25

    Laser evolution and plasma wave excitation by a relativistically-intense short-pulse laser in underdense plasma are investigated in the broad pulse limit, including the effects of pulse steepening, frequency red-shifting, and energy depletion. The nonlinear plasma wave phase velocity is shown to be significantly lower than the laser group velocity and further decreases as the pulse propagates owing to laser evolution. This lowers the thresholds for trapping and wavebreaking, and reduces the energy gain and efficiency of laser-plasma accelerators that use a uniform plasma profile.

  11. Coronary heart disease

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    2008277 Relationship between pulse wave velocity and the NYHA classification of coronary insufficiency.SUN Weiping(孙卫平),et al.Dept Cardiol,Tongji Hosp Tongji Univ,Shanghai 200065.Chin J Intern Med 2008;47(5):382-384.Objective To investigate the relationship between brachial-ankle pulse wave velocity(baPWV)and different stage of cardiac dysfunction.Methods 253 consecutive patients with coronary atherosclerotic heart disease

  12. VLF wave stimulation by pulsed electron beams injected from the Space Shuttle

    Science.gov (United States)

    Reeves, G. D.; Banks, P. M.; Frazer-Smith, A. C.; Neubert, T.; Bush, R. I.

    1988-01-01

    Among the investigations conducted on the Space Shuttle flight STS-3 of March 1982 was an experiment in which a 1-keV, 100-mA electron gun was pulsed at 3.25 and 4.87 kHz. The resultant waves were measured with a broadband plasma wave receiver. At the time of flight the experimental setup was unique in that the electron beam was square wave modulated and that the Shuttle offered relatively long times for in situ measurements of the ionospheric plasma response to the VLF pulsing sequences. In addition to electromagnetic response at the pulsing frequencies the wave exhibited various spectral harmonics as well as the unexpected occurrence of 'satellite lines' around those harmonics. Both phenomena occurred with a variety of different characteristics for different pulsing sequences.

  13. Design and Implementation of High Frequency Ultrasound Pulsed-Wave Doppler Using FPGA

    OpenAIRE

    Hu, Chang-Hong; Zhou, Qifa; Shung, K. Kirk

    2008-01-01

    The development of a field-programmable gate array (FPGA)-based pulsed-wave Doppler processing approach in pure digital domain is reported in this paper. After the ultrasound signals are digitized, directional Doppler frequency shifts are obtained with a digital-down converter followed by a low-pass filter. A Doppler spectrum is then calculated using the complex fast Fourier transform core inside the FPGA. In this approach, a pulsed-wave Doppler implementation core with reconfigurable and rea...

  14. A fast rise time high voltage pulse generator for bounded-wave EMP simulator

    International Nuclear Information System (INIS)

    A high voltage pulse generator with fast rise time is developed. The output wave of this generator is presented. The electromagnetic environment with 1.2 ns or 2.8 ns rise time and 50 ns pulse width can be produced when this generator is connected to bounded-wave EMP simulator which is used to investigate the EMP coupling effects of electrical equipment. (authors)

  15. Saturation properties of four-wave mixing between short optical pulses in semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Mørk, Jesper; Mecozzi, A.; Diez, S.

    1999-01-01

    Summary form only given. The authors report the first comparison between theory and experiment on the four wave mixing between trains of short pulses in semiconductor optical amplifiers. The theory is able to explain all qualitative features seen in the experiment.......Summary form only given. The authors report the first comparison between theory and experiment on the four wave mixing between trains of short pulses in semiconductor optical amplifiers. The theory is able to explain all qualitative features seen in the experiment....

  16. Non-invasive measurement of aortic pressure in patients: Comparing pulse wave analysis and applanation tonometry

    OpenAIRE

    Naidu, M.U.R; C Prabhakar Reddy

    2012-01-01

    Objective: The aim of the present study was to validate and compare novel methods to determine aortic blood pressure non-invasively based on Oscillometric Pulse Wave Velocity (PWV) measurement using four limb-cuff pressure waveforms and two lead Electrocardiogram (ECG) with a validated tonometric pulse wave analysis system in patients. Materials and Methods: After receiving the consent, in 49 patients with hypertension, coronary artery disease, diabetes mellitus, PWV, and central blood p...

  17. Detailed characterization of CW- and pulsed-pump four-wave mixing in highly nonlinear fibers

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Galili, Michael; Grüner-Nielsen, L.;

    2016-01-01

    We present a quantitative comparison of continuouswave- (CW) and pulsed-pump four-wave mixing (FWM) in commercially available highly nonlinear fibers (HNLFs), and suggest properties for which the CW and pulsed FWM bandwidths are limited in practice. The CWand pulsed-pump parametric gain is charac......We present a quantitative comparison of continuouswave- (CW) and pulsed-pump four-wave mixing (FWM) in commercially available highly nonlinear fibers (HNLFs), and suggest properties for which the CW and pulsed FWM bandwidths are limited in practice. The CWand pulsed-pump parametric gain...... bandwidth. However, an inverse scaling of the TOD with the dispersion fluctuations, leads to different CW-optimized fibers, which depend only on the even dispersion-orders....

  18. Quantum-state-preserving optical pulse reshaping and multiplexing by four-wave mixing in a fiber

    DEFF Research Database (Denmark)

    McKinstrie, C. J.; Andersen, Lasse Mejling; Rottwitt, Karsten;

    2012-01-01

    Nondegenerate four-wave mixing driven by two pulsed pumps transfers the quantum state of an input signal pulse to an output idler pulse, which is a frequency-translated and reshaped version of the signal. By varying the pump shapes appropriately, one can connect signal and idler pulses with arbit......Nondegenerate four-wave mixing driven by two pulsed pumps transfers the quantum state of an input signal pulse to an output idler pulse, which is a frequency-translated and reshaped version of the signal. By varying the pump shapes appropriately, one can connect signal and idler pulses...

  19. Selective excitation of the molecular rotational wave packet by two time-delayed laser pulses

    Institute of Scientific and Technical Information of China (English)

    Xu Shu-Wu; Huang Yun-Xia; Ji Xian-Ming

    2011-01-01

    In this paper,we investigate the control of the molecular wave packet of a linear molecule by two femtosecond laser pulses.It is shown that the odd and the even rotational wave packets created by a single laser pulse can be selectively excited by accurately controlling the time delay of another laser pulse.By inserting the peak of the second laser pulse at the position of maximum or minimum value around quarter or three quarter rotational period of the slope curve with odd (or even) rotational wave packet contribution that is created by the first laser pulse,the odd rotational wave packet can be enhanced (or suppressed) while the even rotational wave packet is suppressed (or enhanced).As a result,the molecular alignments around quarter and three quarter rotational periods can be obtained.Moreover,it is also shown that by inserting the second laser pulse around the quarter or three quarter rotational periods,the changes in the maximum degree of the molecular alignment for the odd and the even rotational wave packet contributions are consistent with their corresponding slope curves at these positions.

  20. Dispersion-Flattened Composite Highly Nonlinear Fibre Optimised for Broadband Pulsed Four-Wave Mixing

    DEFF Research Database (Denmark)

    Lillieholm, Mads; Galili, Michael; Oxenløwe, Leif Katsuo

    2016-01-01

    We present a segmented composite HNLF optimised for mitigation of dispersion-fluctuation impairments for broadband pulsed four-wave mixing. The HNLF-segmentation allows for pulsed FWMprocessing of a 13-nm wide input WDM-signal with -4.6-dB conversion efficiency...

  1. Laser air-jet engine: the action of shock waves at low laser pulse repetition rates

    International Nuclear Information System (INIS)

    The impact and thermal action of laser sparks on the reflector of a laser engine in which the propulsion is produced by repetitively pulsed radiation is estimated. It is shown that for a low pulse repetition rate, the thermal contact of a plasma with the reflector and strong dynamic resonance loads are inevitable. These difficulties can be surmounted by using the method based on the merging of shock waves at a high pulse repetition rate. (laser applications)

  2. a New Approach of Dynamic Blood Pressure Measurement Based on the Time Domain Analysis of the Pulse Wave

    Science.gov (United States)

    Zimei, Su; Wei, Xu; Hui, Yu; Fei, Du; Jicun, Wang; Kexin, Xu

    2009-08-01

    In this study the pulse wave characteristics were used as a new approach to measure the human blood pressure. Based the principle of pulse wave and theory of the elastic vascular, the authors analyzed the characteristic of the pulse waveforms and revealed the characteristics points which could be used to represent the blood pressure. In this investigation the relevant mathematical feature was used to identify the relationship between the blood pressure and pulse wave parameters in a more accurate way. It also provided an experimental basis to carry out continuing non-invasive blood pressure monitoring using the pulse wave method.

  3. Aortic pulse wave velocity measurement in systemic sclerosis patients

    Directory of Open Access Journals (Sweden)

    M. Sebastiani

    2012-12-01

    Full Text Available Background. Systemic sclerosis (SSc is characterized by endothelial dysfunction and widespread microangiopathy. However, a macrovascular damage could be also associated. Aortic pulse wave velocity (aPWV is known to be a reliable indicator of arterial stiffness and a useful prognostic predictor of cardiovascular events. Moreover, aPWV may be easily measured by non-invasive, user-friendly tool. Aim of our study was to evaluate aPWV alterations in a series of SSc patients. Methods. The aPWV was evaluated in 35 consecutive female SSc patients and 26 sex- and age-matched healthy controls. aPWV alterations were correlated with cardiopulmonary involvement. Results. A significant increase of aPWV was observed in SSc patients compared to controls (9.4±3.2 m/s vs 7.3±1 m/s; P=0.002. In particular, 14/35 (40% SSc patients and only 1/26 (4% controls (P=0.0009 showed increased aPWV (>9 m/s cut-off value. Moreover, echocardiography evaluation showed an increased prevalence of right atrial and ventricular dilatation (atrial volume: 23.6±6.2 mL vs 20.3±4.3 mL, P=0.026; ventricular diameter 19.5±4.9 mm vs 15.9±1.6 mm; P=0.001 associated to higher values of pulmonary arterial systolic pressure (PAPs in SSc patients (31.5±10.4 mmHg vs 21.6±2.9 mmHg; P50 years old. Furthermore, altered aPWV was more frequently associated with limited cutaneous pattern, longer disease duration (≥5 years, and/or presence of anticentromere antibody (ACA. Conclusions. A significantly higher prevalence of abnormally increased aPWV was evidenced in SSc patients compared to healthy controls. The possibility of more pronounced and diffuse vascular damage in a particular SSc subset (ACA-positive subjects with limited cutaneous scleroderma and longer disease duration might be raised.

  4. Characteristics of Spherical Shock Wave and Circular Pulse Jet Generated by Discharge of Propagating Shock Wave at Open End of Tube

    Institute of Scientific and Technical Information of China (English)

    Tsukasa Irie; Tsuyoshi Yasunobu; Hideo Kashimura; Toshiaki Setoguchi; Kazuyasu Matsuo

    2003-01-01

    When the shock wave propagating in the straight circular tube reaches at the open end, the impulsive wave is generated by the emission of a shock wave from an open end, and unsteady pulse jet is formed near the open end behind the impulsive wave under the specific condition. The pulse jet transits to spherical shock wave with the increase in the strength of shock wave. The strength is dependent on the Mach number of shock wave, which attenuates by propagation distance from the open end. In this study, the mechanism of generating the unsteady pulse jet, the characteristics of the pressure distribution in the flow field and the emission of shock wave from straight circular tube which has the infinite flange at open end are analyzed numerically by the TVD method. Strength of spherical shock wave, relation of shock wave Mach number, distance decay of spherical shock wave and directional characteristics are clarified.

  5. Generation of high harmonics and attosecond pulses with ultrashort laser pulse filaments and conical waves

    Indian Academy of Sciences (India)

    A Couairon; A Lotti; D Faccio; P Di Trapani; D S Steingrube; E Schulz; T Binhammer; U Morgner; M Kovacev; M B Gaarde

    2014-08-01

    Results illustrating the nonlinear dynamics of ultrashort laser pulse filamentation in gases are presented, with particular emphasis on the filament properties useful for developing attosecond light sources. Two aspects of ultrashort pulse filaments are specifically discussed: (i) numerical simulation results on pulse self-compression by filamentation in a gas cell filled with noble gas. Measurements of high harmonics generated by the pulse extracted from the filament allows for the detection of intensity spikes and subcycle pulses generated within the filament. (ii) Simulation results on the spontaneous formation of conical wavepackets during filamentation in gases, which in turn can be used as efficient driving pulses for the generation of high harmonics and isolated attosecond pulses.

  6. Stationary periodic and solitary waves induced in an isotropic plasma by a strong short laser pulse

    International Nuclear Information System (INIS)

    A description of propagation of a relativistically intense short laser pulse into an isotropic plasma is presented. A kinetic equation for the spectral function of the electromagnetic (EM) waves is derived for an arbitrary amplitude pump wave, where the fully relativistic case is considered. The resulting kinetic equation of the spectral function is used along with the self of equations of the plasma to derive a general dispersion relation, and the importance of relativistic effects is pointed out. In the case of a superstrong short laser pulse novel Langmuir waves, with phase velocities larger than the speed of light, and waves of ion-sound type, which are damped only on ions, are found. In addition, for the case when the plasma density along with the mass of the electrons satisfies the 'frozen-in' condition, stationary nonlinear new type of ion-sound waves are investigated. The mechanism of the emission of these waves is also discussed. (author)

  7. A noninvasive method to estimate pulse wave velocity in arteries locally by means of ultrasound.

    Science.gov (United States)

    Brands, P J; Willigers, J M; Ledoux, L A; Reneman, R S; Hoeks, A P

    1998-11-01

    Noninvasive evaluation of vessel wall properties in humans is hampered by the absence of methods to assess directly local distensibility, compliance, and Young's modulus. Contemporary ultrasound methods are capable of assessing end-diastolic artery diameter, the local change in artery diameter as a function of time, and local wall thickness. However, to assess vessel wall properties of the carotid artery, for example, the pulse pressure in the brachial artery still must be used as a substitute for local pulse pressure. The assessment of local pulse wave velocity as described in the present article provides a direct estimate of local vessel wall properties (distensibility, compliance, and Young's modulus) and, in combination with the relative change in artery cross-sectional area, an estimate of the local pulse pressure. The local pulse wave velocity is obtained by processing radio frequency ultrasound signals acquired simultaneously along two M-lines spaced at a known distance along the artery. A full derivation and mathematical description of the method to assess local pulse wave velocity, using the temporal and longitudinal gradients of the change in diameter, are presented. A performance evaluation of the method was carried out by means of experiments in an elastic tube under pulsatile pressure conditions. It is concluded that, in a phantom set-up, the assessed local pulse wave velocity provides reliable estimates for local distensibility. PMID:10385955

  8. Multiple continuous-wave and pulsed modes of a figure-of-eight fibre laser

    Science.gov (United States)

    Pottiez, O.; Martinez-Rios, A.; Monzon-Hernandez, D.; Salceda-Delgado, G.; Hernandez-Garcia, J. C.; Ibarra-Escamilla, B.; Kuzin, E. A.

    2013-03-01

    We study experimentally a figure-of-eight fibre laser including a polarization-imbalanced nonlinear optical loop mirror and a Mach-Zehnder optical filter formed by two fibre tapers placed in series. Depending on the adjustments of two wave retarders included in the setup, different modes of operation of the laser are found. In continuous-wave mode, tunable single-wavelength operation as well as multiwavelength lasing are observed. For some adjustments, self-pulsing also takes place, although the pulses are very unstable. Finally, for some adjustments a mechanical stimulation (a kick) leads to the onset of passive mode locking. Measurements reveal that the mode-locked pulses actually are noise-like pulses. Both stable fundamental mode locking and second-harmonic mode locking with particular dynamics were obtained. In this work, we analyse how simple wave plate adjustments can lead to such a variety of operational modes of the fibre laser.

  9. Eliminating the dipole phase in attosecond pulse characterization using Rydberg wave packets

    Science.gov (United States)

    Pabst, Stefan; Dahlström, Jan Marcus

    2016-07-01

    We propose a technique to fully characterize the temporal structure of extreme ultraviolet pulses by ionizing a bound coherent electronic wave packet. The influence of the dipole phase, which is the main obstacle for state-of-the-art pulse characterization schemes, can be eliminated by angle integration of the photoelectron spectrum. We show that in particular, atomic Rydberg wave packets are ideal and that wave packets involving multiple electronic states provide redundant information that can be used to cross-check the consistency of the phase reconstruction.

  10. INFLUENCE OF PULSED SHORT WAVE (DIAPULSE) TREATMENT ON THE BIOCHEMICAL PARAMETERS CORTISOL AND ALDOSTERONE

    OpenAIRE

    Dogaru Gabriela

    2015-01-01

    Pulsed short waves are part of high frequency therapy; unlike continuous short waves, where the phenomenon of tissular endothermia occurs, they have therapeutic effects that seem to depend rather on the interaction of electromagnetic waves with biological tissue, as they act only through specific electromagnetic energy. The recommended work technique for the use of the Diapulse device is that regardless of the exposed somatic region, there will be an initial exposure of one of the following r...

  11. Elimination of spiral waves and spatiotemporal chaos by the pulse with a specific spatiotemporal configuration

    Institute of Scientific and Technical Information of China (English)

    Yuan Guo-Yong; Yang Shi-Ping; Wang Guang-Rui; Chen Shi-Gang

    2008-01-01

    Spiral waves and spatiotemporal chaos are sometimes harmful and should be controlled.In this paper spiral waves and spatiotemporal chaos are successfully eliminated by the pulse with a very specific spatiotemporal configuration.The excited position D of spiral waves or spatiotemporal chaos is first recorded at an arbitrary time (to).When the system at the domain D enters a recovering state,the external pulse is injected into the domain.If the intensity and the working time of the pulse are appropriate,spiral waves and spatiotemporal chaos can finally be eliminated because counter-directional waves can be generated by the pulse.There are two advantages in the method.One is that the tip can be quickly eliminated together with the body of spiral wave,and the other is that the injected pulse may be weak and the duration can be very short so that the original system is nearly not affected,which is important for practical applications.

  12. Temporal broadening of pulsed waves propagating through turbulent media

    Institute of Scientific and Technical Information of China (English)

    XU; Zhengwen(许正文); WU; Jian(吴健); HUO; Wenping(霍文平); WU; Zhensen(吴振森)

    2003-01-01

    Pulse signals, propagating through a turbulent medium such as the ionosphere, can be distorted by dispersion and scattering from both the background medium and irregularities embedded in. Thus, the mean square pulse width is changed, and temporal broadening is introduced. We carry out a study on the temporal broadening with theoretical analyses and numerical simulations by using an analytical solution of two-frequency mutual coherence function obtained recently by iteration. As a case of study, pulse broadening is investigated in detail in trans-ionospheric propagation. Results show that most contributions are mainly from the dispersion of the background ionosphere and scattering effects of electron density irregularities in most cases.

  13. Relativistic solitary waves modulating long laser pulses in plasmas

    CERN Document Server

    Sánchez-Arriaga, G; Lefebvre, E

    2011-01-01

    This article discusses the existence of solitary electromagnetic waves trapped in a self-generated Langmuir wave and embedded in an infinitely long circularly polarized electromagnetic wave propagating through a plasma. From the mathematical point of view they are exact solutions of the 1-dimensional relativistic cold fluid plasma model with nonvanishing boundary conditions. Under the assumption of traveling wave solutions with velocity $V$ and vector potential frequency $\\omega$, the fluid model is reduced to a Hamiltonian system. The solitary waves are homoclinic (grey solitons) or heteroclinic (dark solitons) orbits to fixed points. By using a dynamical systems description of the Hamiltonian system and a spectral method, we identify a great variety of solitary waves, including asymmetric ones, discuss their disappearance for certain parameter values, and classify them according to: (i) grey or dark character, (ii) the number of humps of the vector potential envelope and (iii) their symmetries. The solution...

  14. Studies of nanosecond pulse surface ionization wave discharges over solid and liquid dielectric surfaces

    International Nuclear Information System (INIS)

    Surface ionization wave discharges generated by high-voltage nanosecond pulses, propagating over a planar quartz surface and over liquid surfaces (distilled water and 1-butanol) have been studied in a rectangular cross section test cell. The discharge was initiated using a custom-made, alternating polarity, high-voltage nanosecond pulse plasma generator, operated at a pulse repetition rate of 100–500 Hz, with a pulse peak voltage and current of 10–15 kV and 7–20 A, respectively, a pulse FWHM of ∼100 ns, and a coupled pulse energy of 2–9 mJ/pulse. Wave speed was measured using a capacitive probe. ICCD camera images demonstrated that the ionization wave propagated predominantly over the quartz wall or over the liquid surface adjacent to the grounded waveguide placed along the bottom wall of the test cell. Under all experimental conditions tested, the surface plasma ‘sheet’ was diffuse and fairly uniform, both for positive and negative polarities. The parameters of ionization wave discharge propagating over distilled water and 1-butanol surfaces were close to those of the discharge over a quartz wall. No perturbation of the liquid surface by the discharge was detected. In most cases, the positive polarity surface ionization wave propagated at a higher speed and over a longer distance compared to the negative polarity wave. For all three sets of experiments (surface ionization wave discharge over quartz, water and 1-butanol), wave speed and travel distance decreased with pressure. Diffuse, highly reproducible surface ionization wave discharge was also observed over the liquid butanol–saturated butanol vapor interface, as well as over the distilled water–saturated water vapor interface, without buffer gas flow. No significant difference was detected between surface ionization discharges sustained using single-polarity (positive or negative), or alternating polarity high-voltage pulses. Plasma emission images yielded preliminary evidence of charge

  15. Single attosecond pulse generation via continuum wave packet interference

    Science.gov (United States)

    Zhou, Shengpeng; Yang, Yujun; Ding, Dajun

    2016-07-01

    A single attosecond pulse generation via continuum-continuum interference is investigated theoretically by exposing a single-electron atom in a femtosecond laser field with the intensity in over-the-barrier ionization regime. We show that the ground state of the atom is depleted in such intense laser field and the high-order harmonics (HHG) via continuum to continuum coherence are generated. In a few-cycle monochromatic laser field (5 fs/800 nm, 1.2×1016 W cm-2), a single attosecond pulse with duration of 49 as is obtained from the HHG. With a two-color laser field combined by 1200 nm (8 fs/7.5×1015 W cm-2) and 800 nm (5 fs/1.0×1016 W cm-2), a shorter single pulse with duration of 29 as can further be produced by changing the relative carrier envelope phase of two laser pulses as a result of controlling the electronic quantum path in the intense electric field. Our results also show that a short single attosecond pulse can be generated in a wide range of the relative carrier envelope phase of the two laser pulses.

  16. Association of Arterial Stiffness and Osteoporosis in Healthy Men Undergoing Screening Medical Examination

    OpenAIRE

    Kim, Nam Lee; Jang, Ha Min; Kim, Sul Ki; Ko, Ki Dong; Hwang, In Cheol; Suh, Heuy Sun

    2014-01-01

    Background Association of arterial stiffness and osteoporosis has been previously reported in women. However, this association is still controversial for men. Therefore, we investigated correlation of arterial stiffness and osteoporosis by measuring brachial-ankle (ba) pulse wave velocity (PWV) and bone mineral density (BMD). Methods We reviewed medical charts of 239 people (women: 128, men: 111) who visited the Health Promotion Center, retrospectively. ba-PWV was measured by automatic wave a...

  17. Estimation of global aortic pulse wave velocity by flow-sensitive 4D MRI.

    Science.gov (United States)

    Markl, Michael; Wallis, Wolf; Brendecke, Stefanie; Simon, Jan; Frydrychowicz, Alex; Harloff, Andreas

    2010-06-01

    The aim of this study was to determine the value of flow-sensitive four-dimensional MRI for the assessment of pulse wave velocity as a measure of vessel compliance in the thoracic aorta. Findings in 12 young healthy volunteers were compared with those in 25 stroke patients with aortic atherosclerosis and an age-matched normal control group (n = 9). Results from pulse wave velocity calculations incorporated velocity data from the entire aorta and were compared to those of standard methods based on flow waveforms at only two specific anatomic landmarks. Global aortic pulse wave velocity was higher in patients with atherosclerosis (7.03 +/- 0.24 m/sec) compared to age-matched controls (6.40 +/- 0.32 m/sec). Both were significantly (P sec). Global aortic pulse wave velocity in young volunteers was in good agreement with previously reported MRI studies and catheter measurements. Estimation of measurement inaccuracies and error propagation analysis demonstrated only minor uncertainties in measured flow waveforms and moderate relative errors below 16% for aortic compliance in all 46 subjects. These results demonstrate the feasibility of pulse wave velocity calculation based on four-dimensional MRI data by exploiting its full volumetric coverage, which may also be an advantage over standard two-dimensional techniques in the often-distorted route of the aorta in patients with atherosclerosis. PMID:20512861

  18. Effect of Local Temperature on the Detecting for Pulse Wave of Local Blood Volume

    Directory of Open Access Journals (Sweden)

    Tingting Yan

    2013-07-01

    Full Text Available [Objective] Temperature of a subject's external body parts is an interference condition in pulse wave of local blood volume measurement. It is necessary to rule it out. By changing the influence factors, an experiment to research the effect of temperature of subjected part in pulse wave of local blood volume measurement was carried out. [Methods] When the 32 experimenters' left middle finger temperature fall below to 20°C, pulse wave of local blood volume would be recorded detected in real-time until the temperature returned to the measured values before the experiment [Results] While the temperature of subjected part ranged from 26°C to 31°C, the parameters of K', K1', K2' and the amplitude of pulse wave remain basically unchanged. [Conclusion] As a result of the research data, it is stipulated that the pulse wave of local blood volume can be measured only if the finger temperature is in the range of 26-31°C.

  19. Validity and reproducibility of arterial pulse wave velocity measurement using new device with oscillometric technique: A pilot study

    OpenAIRE

    Patnaik Amar; Yashmaina Sridhar; Reddy Budda; Naidu Madireddy; Rani Pingali

    2005-01-01

    Abstract Background Availability of a range of techniques and devices allow measurement of many variables related to the stiffness of large or medium sized arteries. There is good evidence that, pulse wave velocity is a relatively simple measurement and is a good indicator of changes in arterial properties. The pulse wave velocity calculated from pulse wave recording by other methods like doppler or tonometry is tedious, time-consuming and above all their reproducibility depends on the operat...

  20. Associations between plasma fibulin-1, pulse wave velocity and diabetes in patients with coronary heart disease

    DEFF Research Database (Denmark)

    Hansen, Maria Lyck; Rasmussen, Lars Melholt

    2015-01-01

    BACKGROUND: Diabetes is related to increased risk of cardiovascular disease, and arterial stiffness and its consequences may be the factor connecting the two. Arterial stiffness is often measured by carotid-femoral pulse wave velocity (cf-PWV), but no plasma biomarker reflecting arterial stiffness...... undergoing coronary artery bypass grafting. METHODS: Pulse wave velocity (PWV) and pulse wave analysis including augmentation index (Aix75) was measured in 273 patients, who subsequently underwent a coronary by-pass operation. Plasma samples were drawn and information was gathered on diabetes status, HbA1c...... indices are not directly related in patients with cardiac disease, despite the fact that both measures are increased among patients with diabetes....

  1. Interference of dissociating wave packets in the I2 molecule driven by femtosecond laser pulses

    Institute of Scientific and Technical Information of China (English)

    Han Yong-Chang; Hu Wen-Hui; Yu Jie; Cong Shu-Lin

    2009-01-01

    The interference between two dissociating wave packets of the I_2 molecule driven by femtosecond laser pulses is theoretically studied by using the time-dependent quantum wave packet method. Both the internuclear distance- and velocity-dependent density functions are calculated and discussed. It is demonstrated that the interference pattern is determined by the phase difference and the delay time between two pump pulses. With two identical pulses with a delay time of 305 fs and a FWHM of 20 fs, more interference fringes can be observed, while with two pump pulses with a delay time of 80 fs and a FWHM of 20 fs, only a few interference fringes can be observed.

  2. Ultra-short pulsed millimeter-wave laser

    Science.gov (United States)

    Wilson, Thomas

    2000-10-01

    High peak power pulses of 1.22-mm wavelength radiation have recently been obtained from a novel cavity-dumped far-infrared optically-pumped laser^1. Smooth reproducible pulses with the following characteristics have been routinely obtained: peak power=25-kW, pulsewidth (FWHM)=5-ns, repetition rate=10 pps. (This compares favorably to typical far-infrared, cavity-dumped output - 11-kW, 30-ns, 1 pps - available from the University of California - Santa Barbara Free Electron Laser). The pumping laser is a grating-tuned, hybrid TEA CO2 laser providing 1J / pulse at the 9P32 transition. The far-infrared gain medium is isotopic (C^13) methyl flouride. Experiments are underway for using the novel source to resonantly excite coherent pulses of 250-GHz longitudinal acoustic phonons in silicon doping superlattices. ^1 Thomas E. Wilson, "Modeling the high-speed switching of far-infrared radiation by photoionization in a semiconductor", Phys. Rev. B 59 (20), 12996 (1999).

  3. Reduction of pulse distortion in travelling wave semiconductor optical amplifiers

    OpenAIRE

    Soneira Ferrando, M. José; Ruiz Moreno, Sergio

    1991-01-01

    The possibility of reducing the gain saturation during the pulse amplification process by means of the compensation of the carrier density variations is investigated. This should be useful in many optical systems and, especially, in high-speed communication systems. Peer Reviewed

  4. Micro-joule sub-10-fs VUV pulse generation by MW pump pulse using highly efficient chirped-four-wave mixing in hollow-core photonic crystal fibers

    OpenAIRE

    Im, Song-Jin

    2013-01-01

    We theoretically study chirped four-wave mixing for VUV pulse generation in hollow-core photonic crystal fibers. We predict the generation of sub-10-fs VUV pulses with energy of up to hundreds of microjoule by broad-band chirped idler pulses at 830 nm and MW pump pulses with narrow-band at 277 nm. MW pump could be desirable to reduce the complexity of the laser system or use a high repetition rate-laser system. The energy conversion efficiency from pump pulse to VUV pulse reaches to 30%. This...

  5. 强化降脂治疗对高血压合并高脂血症患者动脉脉搏波传导速度的影响%Effect of Artery Pulse Wave Velocity by Intensive Lipid-lowering Therapy in Patients with Hypertension Combined Hyperlipidemia

    Institute of Scientific and Technical Information of China (English)

    廖奕华; 邓云梅; 胡晶晶; 马艳丽; 樊琳

    2013-01-01

    cholesterol(HDL-C),low density lipoprotein(LDL-C),high sensitive C reactive protein(hs-CRP)and endothelin(ET)were detected before and after treatment.Result:Compared with normal group,two groups of patients baPWV, hs-CRP and ET levels were significantly elevated ,with significant difference(P<0.01),and it retreated significantly after 6 months treatment(P<0.01);compared with control group,which of intensive lipid-lowering group was decreased obviously,the difference was statistically significant between the groups(P<0.05).Conclusion:Patient with mild-to-moderate hypertension combined hyperlipidemia,intensive lipid-lowering therapy based on the control of blood pressure can futher improve the brachial-ankle artery pulse wave velocity,decreased hs-CRP and ET levels in patients,to improve the state of vascular function with a positive clinical significance.

  6. Pulse wave imaging in normal, hypertensive and aneurysmal human aortas in vivo: a feasibility study

    Science.gov (United States)

    Li, Ronny X.; Luo, Jianwen; Balaram, Sandhya K.; Chaudhry, Farooq A.; Shahmirzadi, Danial; Konofagou, Elisa E.

    2013-07-01

    Arterial stiffness is a well-established biomarker for cardiovascular risk, especially in the case of hypertension. The progressive stages of an abdominal aortic aneurysm (AAA) have also been associated with varying arterial stiffness. Pulse wave imaging (PWI) is a noninvasive, ultrasound imaging-based technique that uses the pulse wave-induced arterial wall motion to map the propagation of the pulse wave and measure the regional pulse wave velocity (PWV) as an index of arterial stiffness. In this study, the clinical feasibility of PWI was evaluated in normal, hypertensive, and aneurysmal human aortas. Radiofrequency-based speckle tracking was used to estimate the pulse wave-induced displacements in the abdominal aortic walls of normal (N = 15, mean age 32.5 ± 10.2 years), hypertensive (N = 13, mean age 60.8 ± 15.8 years), and aneurysmal (N = 5, mean age 71.6 ± 11.8 years) human subjects. Linear regression of the spatio-temporal variation of the displacement waveform in the anterior aortic wall over a single cardiac cycle yielded the slope as the PWV and the coefficient of determination r2 as an approximate measure of the pulse wave propagation uniformity. The aortic PWV measurements in all normal, hypertensive, and AAA subjects were 6.03 ± 1.68, 6.69 ± 2.80, and 10.54 ± 6.52 m s-1, respectively. There was no significant difference (p = 0.15) between the PWVs of the normal and hypertensive subjects while the PWVs of the AAA subjects were significantly higher (p pathologies that regionally alter the arterial wall mechanics.

  7. Carrier-wave steepened pulses and gradient-gated high-order harmonic generation

    CERN Document Server

    Radnor, S B P; Kinsler, P; New, G H C

    2008-01-01

    We show how to optimize the process of high-harmonic generation (HHG) by gating the interaction using the field gradient of the driving pulse. Since maximized field gradients are efficiently generated by self-steepening processes, we first present a generalized theory of optical carrier-wave self-steepened (CSS) pulses. This goes beyond existing treatments, which only consider third-order nonlinearity, and has the advantage of describing pulses whose wave forms have a range of symmetry properties. Although a fertile field for theoretical work, CSS pulses are difficult to realize experimentally because of the deleterious effect of dispersion. We therefore consider synthesizing CSS-like profiles using a suitably phased sub-set of the harmonics present in a true CSS wave form. Using standard theoretical models of HHG, we show that the presence of gradient-maximized regions on the wave forms can raise the spectral cut-off and so yield shorter attosecond pulses. We study how the quality of the attosecond bursts cr...

  8. An attempt to reconstruct the lithotriptor shock wave pulse in kidney: possible temperature effects.

    Science.gov (United States)

    Filipczyński, L; Etienne, J; Piechocki, M

    1992-01-01

    Based on measurements carried out in water in two lithotriptor systems, the authors have made an attempt to reconstruct numerically amplitudes and shapes of shock wave pulses penetrating into kidney which differ from those in water. The difference between these pulses and those observed in water was analyzed and was also demonstrated experimentally. The amplitude and the steepness of the reconstructed pulse front were shown to be much lower than in water depending on the distance of the kidney stone from the patient's body surface. For a distance equal to 4 cm, the shock wave pulse amplitude of 40 MPa in water was estimated to decrease in the kidney by a factor of about two and the steepness of the positive shock pulse front to decrease several times. The analysis was carried out by considering the possible changes of absorption and attenuation in tissues which increase in an unknown way with the wave amplitude. It was shown that the temperature elevation caused by the increase of nonlinear high amplitude absorption is limited due to a corresponding increase in attenuation of the shock wave penetrating soft tissues. The temperature elevation was estimated on the basis of this work to be at most 1.8 times that one estimated in the case of two considered lithotripsy systems when assuming small amplitude absorption and attenuation coefficients.

  9. Magnetostatic-Wave-Based Magneto-Optic Pulse Compression by Control of Phase Mismatching

    Institute of Scientific and Technical Information of China (English)

    WU Bao-Jian; GAO Xiang

    2008-01-01

    Microwave magnetostatic waves (MSWs) as moving gratings in magneto-optic (MO) film can lead to the Bragg diffraction of guided optical waves (GOWs). The MO coupling characteristics are responsible for the amplitude and phase frequency spectra of diffracted pulses and even result in the compression of chirped optical pulses in time domain. We theoretically investigate the noncollinear diffraction of linearly chirped Gaussian optical pulses by continuous magnetostatic forward volume waves in detail. For a given chirped optical pulse, with the increase of phase-mismatching slopes, the compression efficiency (CE) is gradually improved up to the maximum followed by the transition of diffracted pulses from single peak to multi peaks. The larger the chirp parameter is,the smaller the required phase-mismatching slope to achieve the maximal CE is. However, the rise of the chirp parameter or phase-mismatching slope reduces the relative peak intensity of the diffracted pulse. Lastly, it is pointed out that the phase-mismatching slope can be greatly increased by using the high-order modes of MSWs and GOWs.

  10. VLF wave emissions by pulsed and dc electron beams in space. I - Spacelab 2 observations

    Science.gov (United States)

    Reeves, G. D.; Banks, P. M.; Neubert, T.; Bush, R. I.; Williamson, P. R.

    1988-01-01

    The properties of radio waves generated by electron beams in space were investigated using data from the wideband wave receiver on the Spacelab 2. The VLF observations were found to confirm the results of the STS 3/OSS-1 mission. It was found that a 1-keV electron beam injected from the orbiter produced copious broadband electromagnetic emissions. When the electron beam was square-wave modulated, narrow-band emissions at the pulsing frequency and harmonics of that frequency were produced along with the broadband emissions. The observations indicated that dc 50-mA electron beams and pulsed 50-percent duty-cycle 100-mA beams produce broadband radiation which is comparable in intensity and spectral shape at all points for which the wave field was sampled.

  11. Group Velocity Reduction of Light Pulses in Photorefractive Two-Wave Mixing

    Institute of Scientific and Technical Information of China (English)

    张国权; 董嵘; 许京军

    2003-01-01

    We show theoretically that the group velocity of light pulses can be reduced significantly by use of the steep dispersion properties of the phase coupling effect in the photorefractive two-wave mixing process. The group velocity of light pulses of the order of 0.1 m/s can be achieved in typical photorefractive BSOcrystals with an appropriate externally applied electric field and moving gratings of appropriate speeds. It is also shown that the slowly propagating light pulses can be set to be amplified after passing through the photorefractive material.

  12. Detection and analysis of multi-dimensional pulse wave based on optical coherence tomography

    Science.gov (United States)

    Shen, Yihui; Li, Zhifang; Li, Hui; Chen, Haiyu

    2014-11-01

    Pulse diagnosis is an important method of traditional Chinese medicine (TCM). Doctors diagnose the patients' physiological and pathological statuses through the palpation of radial artery for radial artery pulse information. Optical coherence tomography (OCT) is an useful tool for medical optical research. Current conventional diagnostic devices only function as a pressure sensor to detect the pulse wave - which can just partially reflect the doctors feelings and lost large amounts of useful information. In this paper, the microscopic changes of the surface skin above radial artery had been studied in the form of images based on OCT. The deformation of surface skin in a cardiac cycle which is caused by arterial pulse is detected by OCT. The patient's pulse wave is calculated through image processing. It is found that it is good consistent with the result conducted by pulse analyzer. The real-time patient's physiological and pathological statuses can be monitored. This research provides a kind of new method for pulse diagnosis of traditional Chinese medicine.

  13. A Distinguishing Arterial Pulse Waves Approach by Using Image Processing and Feature Extraction Technique.

    Science.gov (United States)

    Chen, Hsing-Chung; Kuo, Shyi-Shiun; Sun, Shen-Ching; Chang, Chia-Hui

    2016-10-01

    Traditional Chinese Medicine (TCM) is based on five main types of diagnoses methods consisting of inspection, auscultation, olfaction, inquiry, and palpation. The most important one is palpation also called pulse diagnosis which is to measure wrist artery pulse by doctor's fingers for detecting patient's health state. In this paper, it is carried out by using a specialized pulse measuring instrument to classify one's pulse type. The measured pulse waves (MPWs) were segmented into the arterial pulse wave curve (APWC) by image proposing method. The slopes and periods among four specific points on the APWC were taken to be the pulse features. Three algorithms are proposed in this paper, which could extract these features from the APWCs and compared their differences between each of them to the average feature matrix, individually. These results show that the method proposed in this study is superior and more accurate than the previous studies. The proposed method could significantly save doctors a large amount of time, increase accuracy and decrease data volume. PMID:27562483

  14. Transporting Rydberg Electron Wave Packets with Chirped Trains of Pulses

    International Nuclear Information System (INIS)

    A protocol for steering Rydberg electrons towards targeted final states is realized with the aid of a chirped train of half-cycle pulses (HCPs). Its novel capabilities are demonstrated experimentally by transporting potassium atoms excited to the lowest-lying quasi-one-dimensional states in the ni=350 Stark manifold to a narrow range of much higher-n states. We demonstrate that this coherent state transfer is, to a high degree, reversible. The protocol allows for remarkable selectivity and is highly efficient, with typically over 80% of the parent atoms surviving the HCP sequence

  15. Full-wave reflection of lightning long-wave radio pulses from the ionospheric D region: Numerical model

    Science.gov (United States)

    Jacobson, Abram R.; Shao, Xuan-Min; Holzworth, Robert

    2009-03-01

    A model is developed for calculating ionospheric reflection of electromagnetic pulses emitted by lightning, with most energy in the long-wave spectral region (f ~ 3-100 kHz). The building block of the calculation is a differential equation full-wave solution of Maxwell's equations for the complex reflection of individual plane waves incident from below, by the anisotropic, dissipative, diffuse dielectric profile of the lower ionosphere. This full-wave solution is then put into a summation over plane waves in an angular direct Fourier transform to obtain the reflection properties of curved wavefronts. This step models also the diffraction effects of long-wave ionospheric reflections observed at short or medium range (~200-500 km). The calculation can be done with any arbitrary but smooth dielectric profile versus altitude. For an initial test, this article uses the classic D region exponential profiles of electron density and collision rate given by Volland. With even these simple profiles, our model of full-wave reflection of curved wavefronts captures some of the basic attributes of observed reflected waveforms recorded with the Los Alamos Sferic Array. A follow-on article will present a detailed comparison with data in order to retrieve ionospheric parameters.

  16. Ion acceleration in a solitary wave by an intense picosecond laser pulse.

    Science.gov (United States)

    Zhidkov, A; Uesaka, M; Sasaki, A; Daido, H

    2002-11-18

    Acceleration of ions in a solitary wave produced by shock-wave decay in a plasma slab irradiated by an intense picosecond laser pulse is studied via particle-in-cell simulation. Instead of exponential distribution as in known mechanisms of ion acceleration from the target surface, these ions accelerated forwardly form a bunch with relatively low energy spread. The bunch is shown to be a solitary wave moving over expanding plasma; its velocity can exceed the maximal velocity of ions accelerated forward from the rear side of the target.

  17. The Role of Systemic Arterial Stiffness in Open-Angle Glaucoma with Diabetes Mellitus

    OpenAIRE

    Seong Hee Shim; Chan Yun Kim; Joon Mo Kim; Da Yeong Kim; Yang Jae Kim; Jeong Hun Bae; Ki Chul Sung

    2015-01-01

    Purpose. To investigate the role of systemic arterial stiffness in glaucoma patients with diabetes mellitus (DM). Design. Retrospective, cross-sectional study. Participants. DM subjects who underwent brachial-ankle pulse wave velocity (baPWV) were recruited. Methods. Glaucoma patients (n = 75) and age-matched control subjects (n = 92) were enrolled. Systemic examination including BaPWV and detailed eye examination were performed. The glaucoma group was divided into subgroups of normal tension...

  18. Clinical Significance of Arterial Stiffness and Thickness Biomarkers in Type 2 Diabetes Mellitus: An Up-To-Date Meta-Analysis

    OpenAIRE

    Yapei, Yang; Xiaoyan, Ren; Sha, Zeng; Li, Pan; Xiao, Meng; Shuangfeng, Chen; Lexin, Wang; Lianqun, Cui

    2015-01-01

    Background Type 2 Diabetes mellitus (T2DM) is associated with increased risk of cardiovascular disease (CVD). Previous studies explored the association of T2DM with arterial stiffness and thickness biomarkers including the augmentation index (AIX), aortic pulse wave velocity (aPWV), brachial-ankle PWV (baPWV), carotid intima-media wall thickness (IMT) as well as blood pressure (BP), low density lipoprotein cholesterol (LDL-C); however the conclusions are either inconsistent or incomprehensive...

  19. Association between non-alcoholic fatty liver disease and arterial stiffness in the non-obese, non-hypertensive, and non-diabetic young and middle-aged Chinese population

    OpenAIRE

    Yu, Xin-Yan; Zhao, Yi; Song, Xiao-xiao; Song, Zhen-ya

    2014-01-01

    Background and objective: Non-alcoholic fatty liver disease (NAFLD) is associated with arterial stiffness in the general population. Age, obesity, hypertension, and diabetics are risk factors for arterial stiffness. In this study, we aimed to investigate the association between NAFLD and arterial stiffness as measured by brachial-ankle pulse wave velocity (baPWV) in the non-obese, non-hypertensive, and non-diabetic young and middle-aged Chinese population. Methods: A cross-sectional study wit...

  20. Arterial Stiffening and Clinical Outcomes in Dialysis Patients

    OpenAIRE

    Kato, Akihiko

    2015-01-01

    Cardiovascular disease (CVD) is an important cause of morbidity and mortality in dialysis patients. Brachial-ankle pulse wave velocity (baPWV) is more efficient to handily assess arteriosclerosis than aortic PWV. The cardio-ankle vascular index (CAVI) is also a novel blood pressure-independent arterial stiffness parameter. In dialysis patients, both baPWV and CAVI are increased compared to general subjects. Several studies have demonstrated that increased baPWV is associated with carotid athe...

  1. Arterial stiffness is inversely associated with a better running record in a full course marathon race

    OpenAIRE

    Jung, Su-Jeen; Park, Jae-Hyoung; Lee, Sewon

    2014-01-01

    [Purpose] Arterial stiffness is an independent predictor of cardiovascular risk and may contribute to reduced running capacity in humans. This study investigated the relationship between course record and arterial stiffness in marathoners who participated in the Seoul International Marathon in 2012. [Methods] A total of 30 amateur marathoners (Males n = 28, Females n = 2, mean age = 51.6 ± 8.3 years) were assessed before and after the marathon race. Brachial-ankle pulse wave velocity (ba-PWV)...

  2. Pulse-wave timing between the cervical carotid and intracranial arteries by means of wavelet transform

    NARCIS (Netherlands)

    Journee, HL; de Jonge, AB; Hamoen, DJ; Smit, A; van Bruggen, AC; Mooij, JJA; Boom, H; Robinson, C; Rutten, W; Neuman, M; Wijkstra, H

    1997-01-01

    Wavelet Transform (WT) is applied in a method for timing the blood pulse wave between the internal carotid artery: and one of the intracranial arteries. The required accuracy is a few milliseconds. In contrast to the Fourier Transform (FT), WT is an appropriate technique for the detection of non-sta

  3. Imaging pulse wave velocity in mouse retina using swept-source OCT (Conference Presentation)

    Science.gov (United States)

    Song, Shaozhen; Wei, Wei; Wang, Ruikang K.

    2016-03-01

    Blood vessel dynamics has been a significant subject in cardiology and internal medicine, and pulse wave velocity (PWV) on artery vessels is a classic evaluation of arterial distensibility, and has never been ascertained as a cardiovascular risk marker. The aim of this study is to develop a high speed imaging technique to capture the pulsatile motion on mouse retina arteries with the ability to quantify PWV on any arterial vessels. We demonstrate a new non-invasive method to assess the vessel dynamics on mouse retina. A Swept-source optical coherence tomography (SS-OCT) system is used for imaging micro-scale blood vessel motion. The phase-stabilized SS-OCT provides a typical displacement sensitivity of 20 nm. The frame rate of imaging is ~16 kHz, at A-line rate of ~1.62 MHz, which allows the detection of transient pulse waves with adequate temporal resolution. Imaging volumes with repeated B-scans are obtained on mouse retina capillary bed, and the mouse oxymeter signal is recorded simultaneously. The pulse wave on artery and vein are resolved, and with the synchronized heart beat signal, the temporal delay on different vessel locations is determined. The vessel specific measurement of PWV is achieved for the first time with SS-OCT, for pulse waves propagating more than 100 cm/s. Using the novel methodology of retinal PWV assessment, it is hoped that the clinical OCT scans can provide extended diagnostic information of cardiology functionalities.

  4. Theory of nondegenerate four-wave mixing between pulses in a semiconductor waveguide

    DEFF Research Database (Denmark)

    Mørk, Jesper; Mecozzi, A.

    1997-01-01

    We develop a perturbation theory for calculating the effects of saturation on nondegenerate four-wave mixing between short optical pulses in a semiconductor optical amplifier. Saturation due to ultrafast intraband dynamics like carrier heating and spectral hole burning is found to be important...

  5. Clinical characteristic of pulse wave velocity and arterial compliance in elderly patients with diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    张红

    2013-01-01

    Objective To explore the clinical characteristics of pulse wave velocity,arterial compliance and cardiovascular risk factors in elderly patients with type 2 diabetes mellitus.Methods A total of 363 patients were selected and divided into 4 groups:diabetic group,diabetic

  6. The use of pulsed-wave Doppler in prenatal diagnosis. An update

    OpenAIRE

    Degani, S.

    2007-01-01

    Pulsed wave Doppler ultrasound of fetal vessels confirms the similarity of human fetal circulation to the experimental animal physiology, The result of a multitude of research articles in this field is the clinical use of various components of fetal circulation in perinatal medicine. Umbilical, uterine and fetal cerebral arteries as well as the fetal venous circulation show the potential of Doppler ultrasonography.

  7. Diode-pumped intracavity optical parametric oscillator in pulsed and continuous-wave operation

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Skettrup, Torben; Petersen, O.B.;

    2002-01-01

    An intracavity optical parametric oscillator is investigated in pulsed and continuous-wave operation. The intracavity optical parametric oscillator is based on Yb:YAG as the laser material and a periodically poled lithium niobate crystal as the nonlinear material. Tuneable idler output powers above...

  8. Comparison of two instruments measuring carotid-femoral pulse wave velocity: Vicorder versus SphygmoCor

    NARCIS (Netherlands)

    E.M. van Leeuwen-Segarceanu; W.F. Tromp; W.J.W. Bos; O.J. Vogels; J.W. Groothoff; J.H. van der Lee

    2010-01-01

    Background The carotid-femoral pulse wave velocity (PWVcf) is used as an indicator of arterial stiffness. It is often measured using applanation tonometry, for instance with the SphygmoCor. In young children, this method is difficult to perform. Therefore, techniques are needed that are less depende

  9. Traveling-wave pulse on a superconductive active transmission line using resonant tunneling diodes

    International Nuclear Information System (INIS)

    Analytic study and computer experiment investigations on a superconductive active transmission line using resonant tunneling diodes (RTDs) are discussed. It is shown, based on nonlinear wave propagation effects, that the line supports pulse propagation appearing as pairs of kink–antikink profiles. This behavior is due to compensation between the effects of amplification and dissipation along the network. (paper)

  10. Traveling-wave pulse on a superconductive active transmission line using resonant tunneling diodes

    Science.gov (United States)

    Klofaï, Yerima; Essimbi, B. Z.; Jäger, D.

    2013-10-01

    Analytic study and computer experiment investigations on a superconductive active transmission line using resonant tunneling diodes (RTDs) are discussed. It is shown, based on nonlinear wave propagation effects, that the line supports pulse propagation appearing as pairs of kink-antikink profiles. This behavior is due to compensation between the effects of amplification and dissipation along the network.

  11. PULSED-WAVE TRANSMITRAL DOPPLER DO NOT DIAGNOSE MODERATE ACUTE REJECTION AFTER HEART-TRANSPLANTATION

    NARCIS (Netherlands)

    MANNAERTS, HF; SIMOONS, ML; BALK, AH; TIJSSEN, J; VANDERBORDEN, SG; ZONDERVAN, PE; MOCHTAR, B; WEIMAR, W; ROELANDT, [No Value

    1993-01-01

    The value of pulsed-wave transmitral Doppler for the diagnosis of moderate acute rejection was examined in a total of 347 Doppler recordings obtained in 32 consecutive cardiac allograft recipients. Serial Doppler examinations (median, 11 per patient; range, 1 to 23) were performed simultaneously wit

  12. Dissipation of Alfven wave pulses propagating along dipole magnetic tubes with reflections at the ionosphere

    NARCIS (Netherlands)

    Erkaev, NV; Shaidurov, VA; Semenov, VS; Biernat, HK; Heidorn, D; Lakhina, GS

    2006-01-01

    A ratio of the maximal and minimal cross sections of the magnetic tube (contraction ratio) is a crucial parameter which affects very strongly on reflections of MHD wave pulses propagating along a narrowing magnetic flux tube. In cases of large contraction ratios of magnetospheric magnetic tubes, the

  13. Scattering of a pulsed wave by a sphere with an eccentric spherical inclusion.

    Science.gov (United States)

    Vervelidou, Fotini; Chrissoulidis, Dimitrios

    2012-04-01

    A dielectric sphere with an eccentric spherical dielectric inclusion and an incident amplitude-modulated plane electromagnetic wave constitute an exterior radiation problem, which is solved in this paper. A solution is obtained by combined use of the Fourier transform and the indirect-mode-matching method. The analysis yields a set of linear equations for the wave amplitudes of the frequency-domain expansion of the electric-field intensity within and outside the externally spherical inhomogeneous body; that set is solved by truncation and matrix inversion. The shape of the backscattered pulse in the time domain is determined by application of the inverse fast Fourier transform. Numerical results are shown for a pulse backscattered by an acrylic sphere that contains an eccentric spherical cavity. The effects of cavity position and size on pulse spreading and delay are discussed. PMID:22472840

  14. Non-contact measurement of pulse wave velocity using RGB cameras

    Science.gov (United States)

    Nakano, Kazuya; Aoki, Yuta; Satoh, Ryota; Hoshi, Akira; Suzuki, Hiroyuki; Nishidate, Izumi

    2016-03-01

    Non-contact measurement of pulse wave velocity (PWV) using red, green, and blue (RGB) digital color images is proposed. Generally, PWV is used as the index of arteriosclerosis. In our method, changes in blood volume are calculated based on changes in the color information, and is estimated by combining multiple regression analysis (MRA) with a Monte Carlo simulation (MCS) model of the transit of light in human skin. After two pulse waves of human skins were measured using RGB cameras, and the PWV was calculated from the difference of the pulse transit time and the distance between two measurement points. The measured forehead-finger PWV (ffPWV) was on the order of m/s and became faster as the values of vital signs raised. These results demonstrated the feasibility of this method.

  15. Allowable propagation of short pulse laser beam in a plasma channel and electromagnetic solitary waves

    International Nuclear Information System (INIS)

    Nonparaxial and nonlinear propagation of a short intense laser beam in a parabolic plasma channel is analyzed by means of the variational method and nonlinear dynamics. The beam propagation properties are classified by five kinds of behaviors. In particularly, the electromagnetic solitary wave for finite pulse laser is found beside the other four propagation cases including beam periodically oscillating with defocussing and focusing amplitude, constant spot size, beam catastrophic focusing. It is also found that the laser pulse can be allowed to propagate in the plasma channel only when a certain relation for laser parameters and plasma channel parameters is satisfied. For the solitary wave, it may provide an effective way to obtain ultra-short laser pulse.

  16. Wave-shaping of pulse tube cryocooler components for improved performance

    Science.gov (United States)

    Antao, Dion Savio; Farouk, Bakhtier

    2014-11-01

    The method of wave-shaping acoustic resonators is applied to an inertance type cryogenic pulse tube refrigerator (IPTR) to improve its performance. A detailed time-dependent axisymmetric experimentally validated computational fluid dynamic (CFD) model of the PTR is used to predict its performance. The continuity, momentum and energy equations are solved for both the refrigerant gas (helium) and the porous media regions (the regenerator and the three heat-exchangers) in the PTR. An improved representation of heat transfer in the porous media is achieved by employing a thermal non-equilibrium model to couple the gas and solid (porous media) energy equations. The wave-shaped regenerator and pulse tube studied have cone geometries and the effects of different cone angles and the orientation (nozzle v/s diffuser mode) on the system performance are investigated. The resultant spatio-temporal pressure, temperature and velocity fields in the regenerator and pulse tube components are evaluated. The performance of these wave-shaped PTRs is compared to the performance of a non wave-shaped system with cylindrical components. Better cooling is predicted for the cryocooler using wave-shaped components oriented in the diffuser mode.

  17. Detection of Breaking Waves Using X-Band Pulse Radar in the Nearshore Region

    Institute of Scientific and Technical Information of China (English)

    Y.C.Lin; C.C.Chang; M.C.Lee; H.C.Chan; J.M.Leu

    2013-01-01

    An X-band pulsed Doppler microwave radar has been used to determine the characteristics of breaking waves.Field experiments were conducted at the Shuang-Si estuary in the north of Taiwan in the winter of 2005.Analyses on maxima radar cross section and Doppler frequency shift are done to characterize wave breaking zones.Based on observations of breaking waves,the wave breaking zones are shown to be located at water depths of 1.8 to 2.2 m in the experimental site.In general,the results indicate that a radar system has the potential to delineate the spatial variation of breaking waves clearly and that this is sufficient to achieve a measurement operation for near-shore air-sea interaction events.

  18. Unidirectional Amplification and Shaping of Optical Pulses by Three-Wave Mixing with Negative Phonons

    CERN Document Server

    Popov, Alexander K; Myslivets, Sergey A; Slabko, Vitaly V

    2013-01-01

    A possibility to greatly enhance frequency-conversion efficiency of stimulated Raman scattering is shown by making use of extraordinary properties of three-wave mixing of ordinary and backward waves. Such processes are commonly attributed to negative-index plasmonic metamaterials. This work demonstrates the possibility to replace such metamaterials that are very challenging to engineer by readily available crystals which support elastic waves with contra-directed phase and group velocities. The main goal of this work is to investigate specific properties of indicated nonlinear optical process in short pulse regime and to show that it enables elimination of fundamental detrimental effect of fast damping of optical phonons on the process concerned. Among the applications is the possibility of creation of a family of unique photonic devices such as unidirectional Raman amplifiers and femtosecond pulse shapers with greatly improved operational properties.

  19. Shock wave acceleration of protons in inhomogeneous plasma interacting with ultrashort intense laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Lecz, Zs. [ELI-ALPS, ELI-HU Nkft., Szeged (Hungary); Andreev, A. [ELI-ALPS, ELI-HU Nkft., Szeged (Hungary); Max-Born Institute, Berlin (Germany)

    2015-04-15

    The acceleration of protons, triggered by solitary waves in expanded solid targets is investigated using particle-in-cell simulations. The near-critical density plasma is irradiated by ultrashort high power laser pulses, which generate the solitary wave. The transformation of this soliton into a shock wave during propagation in plasma with exponentially decreasing density profile is described analytically, which allows to obtain a scaling law for the proton energy. The high quality proton bunch with small energy spread is produced by reflection from the shock-front. According to the 2D simulations, the mechanism is stable only if the laser pulse duration is shorter than the characteristic development time of the parasitic Weibel instability.

  20. INFLUENCE OF PULSED SHORT WAVE (DIAPULSE TREATMENT ON THE BIOCHEMICAL PARAMETERS CORTISOL AND ALDOSTERONE

    Directory of Open Access Journals (Sweden)

    Dogaru Gabriela

    2015-12-01

    Full Text Available Pulsed short waves are part of high frequency therapy; unlike continuous short waves, where the phenomenon of tissular endothermia occurs, they have therapeutic effects that seem to depend rather on the interaction of electromagnetic waves with biological tissue, as they act only through specific electromagnetic energy. The recommended work technique for the use of the Diapulse device is that regardless of the exposed somatic region, there will be an initial exposure of one of the following regions: prehepatic, epigastric or lumbar (for action on the adrenal glands. Considering the role and the effects of the hormones of the adrenocortical gland, particularly glucocorticoids, on the body, which influence the inflammatory response of the connective tissue, with a role in rheumatoid pathology, we monitored the changes in the function of this gland. The biochemical parameters cortisol and aldosterone were quantitatively assessed in patients with complex regional pain syndrome type I (algoneurodystrophy treated with pulsed short waves, who were initially exposed to radiation of the lumbar region. In the same treatment session, all patients were exposed to radiation of the lumbar region, at a dose of 4/400 impulses/sec., for 10 minutes, followed by radiation of the affected region at a dose of 6/600 impulses/sec., for 10 minutes. There was one treatment session per day, for 14 days. It was demonstrated that radiation of the lumbar region at a dose of 4/400 impulses/sec. caused no changes in the hormonal function of the adrenal gland, i.e. no hypo- or hyperfunction; there was no overstrain or overstress after exposure to pulsed short waves, which is an important aspect, with applicability in clinical practice. Studies demonstrated both the local and the general, systemic influence of pulsed short waves, the induced changes being for the most part strictly dependent on the dose used.

  1. The performance of reflectometers at continuous wave and pulsed-neutron sources

    International Nuclear Information System (INIS)

    To quantify gains from time-of-flight (TOF) methods, identical reflectometers viewing a continuous wave (CW) neutron source and a variety of pulsed-neutron sources were simulated using a Monte Carlo technique. Reflectivity profiles obtained for a simple thin-film, reflecting sample were nearly identical in all simulations, and models fitted to the simulated data yielded parameters (film thickness, surface roughness, and scattering length density) that were equally accurate and precise in all cases. The simulations confirm the power of the TOF method and demonstrate that the performance of pulsed sources for reflectometry does not scale simply as the inverse duty factor of the source. In the case of long-pulse sources, the simulations suggest that pulse tails have little effect on results obtained from specular reflectometry and that maximum brightness of the neutron source should be the primary design criterion. (author) 2 figs., 2 tabs., 5 refs

  2. An Analysis of Pulsed Wave Ultrasound Systems for Blood Velocity Estimation

    DEFF Research Database (Denmark)

    Jensen, J. A.

    1995-01-01

    of the received signal. The time evolution and distribution of velocity can then be found by using samples from a number of pulse-echo lines. Making a short-time Fourier transform of the data reveals the velocity distribution in the range gate over time. Such systems are called Doppler ultrasound systems implying......Pulsed wave ultrasound systems can be used for determining blood's velocity non-invasively in the body. A region of interest is selected, and the received signal is range gated to measure data from the region. One complex sample value is acquired for each pulse emission after complex demodulation...... and the number of pulse emissions aect the result. The nal equation for the received signal is quite complicated, and a simplied interpretation is therefore also given. This readily reveals the infuence from transducer bandwidth, attenuation, non-linear eects, classical Doppler eect, and scattering....

  3. Effects of azelnidipine and amlodipine on artery stiffness and dynamic pulse pressure in patients with essential hypertension%阿折地平与氨氯地平对高血压病患者动脉僵硬度与动态脉压的影响

    Institute of Scientific and Technical Information of China (English)

    黄荣杰; 郑云香; 何美霖

    2012-01-01

    Objective To investigate the impacts of azelnidipine and mlodipine on artery stiffness and dynamic pulse pressure in patients with essential hypertension. Methods Seventy-six hypertensive patients were enrolled into the azelnidipine group and the amlodipine group in this randomized double-blind study. Each patient was given azelnidipine (8 mg) or amlodipine (5 mg) orally everyday for 12 weeks after placebo treatment. The biochemical items, the automatic blood pressure monitor (ABPM) and the brachial ankle pulse wave velocity (baPWV) were determined before and after drug treatment, respectively. Results (1) The seat pressure, ABPM paremnents, baPWV and APP decreased in two groups after 12- week treatment, respectively. (2) No significant differences for the ABPM paremnents, baPWV and APP were shown in two groups. Conclusion Azelnidipine and amlodipine can both markedly decrease baPWV and APP in patients with essential hypertension with no significant difference.%目的:研究阿折地平与氨氯地平对轻中度高血压病患者动脉僵硬度及动态脉压差(APP)的影响.方法:随机双盲双模拟平行对照将76例高血压病患者分为阿折地平组和氨氯地平组,安慰剂期后进入12周试验期,给予阿折地平8 mg或氨氯地平5 mg,每天1次,口服,安慰剂期及试验期结束前行常规生化、动态血压监测、踝-臂脉搏波传导速度(baPWV)测定.结果:(1)与治疗前相比,两组患者坐位及动态血压参数、baPWV及APP均明显降低;(2)12周后两组患者相比,动态血压参数、APP及baPWV均无明显差异.结论:阿折地平与氨氯地平均能有效降低轻中度高血压病患者动脉僵硬度及APP,但两者疗效无明显差异.

  4. Transformation of the Spatial Structure of an Optical Echo-Hologram Response by External Non-Resonant Pulses of Electromagnetic Standing Waves

    Science.gov (United States)

    Sakhbieva, A. R.; Nefed‧ev, L. A.; Garnaeva, G. I.

    2015-11-01

    It was shown that non-resonant electromagnetic standing wave pulses between exciting laser pulses during formation of a stimulated echo hologram transformed the wave front of the stimulated echo-hologram response.

  5. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    International Nuclear Information System (INIS)

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by “fresh” electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam

  6. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    Science.gov (United States)

    Ginzburg, N. S.; Zotova, I. V.; Sergeev, A. S.; Zaslavsky, V. Yu.; Zheleznov, I. V.; Samsonov, S. V.; Mishakin, S. V.

    2015-11-01

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by "fresh" electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam.

  7. Evaluation of arterial propagation velocity based on the automated analysis of the Pulse Wave Shape

    International Nuclear Information System (INIS)

    This paper proposes the automatic estimation of the arterial propagation velocity from the pulse wave raw records measured in the region of the radial artery. A fully automatic process is proposed to select and analyze typical pulse cycles from the raw data. An adaptive neuro-fuzzy inference system, together with a heuristic search is used to find a functional approximation of the pulse wave. The estimation of the propagation velocity is carried out via the analysis of the functional approximation obtained with the fuzzy model. The analysis of the pulse wave records with the proposed methodology showed small differences compared with the method used so far, based on a strong interaction with the user. To evaluate the proposed methodology, we estimated the propagation velocity in a population of healthy men from a wide range of ages. It has been found in these studies that propagation velocity increases linearly with age and it presents a considerable dispersion of values in healthy individuals. We conclude that this process could be used to evaluate indirectly the propagation velocity of the aorta, which is related to physiological age in healthy individuals and with the expectation of life in cardiovascular patients.

  8. Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, N. S., E-mail: ginzburg@appl.sci-nnov.ru; Zaslavsky, V. Yu. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ul' yanov Str., 603950 Nizhny Novgorod (Russian Federation); Nizhny Novgorod State University, 23 Gagarin Ave., 603950 Nizhny Novgorod (Russian Federation); Zotova, I. V.; Sergeev, A. S.; Zheleznov, I. V.; Samsonov, S. V.; Mishakin, S. V. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ul' yanov Str., 603950 Nizhny Novgorod (Russian Federation)

    2015-11-15

    A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by “fresh” electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam.

  9. Heart-Carotid Pulse Wave Velocity a Useful Index of Atherosclerosis in Chinese Hypertensive Patients.

    Science.gov (United States)

    Li, Chunyue; Xiong, Huahua; Pirbhulal, Sandeep; Wu, Dan; Li, Zhenzhou; Huang, Wenhua; Zhang, Heye; Wu, Wanqing

    2015-12-01

    This study was designed to investigate the relationship between heart-carotid pulse wave velocity (hcPWV) and carotid intima-media thickness (CIMT) in hypertensive patients, and also to examine the effect of pre-ejection period (PEP) on it. Doppler ultrasound device was used to measure CIMT in left common carotid artery. Hypertensive patients were divided into normal (n = 36, CIMT ≤0.8 mm) and thickened (n = 31, CIMT > 0.8 mm) group. Electrocardiogram R-wave-based carotid pulse wave velocity (rcPWV) and aortic valve-carotid pulse wave velocity (acPWV) were calculated as the ratio of the travel length to the pulse transit time with or without PEP, respectively. CIMT has significant relations with rcPWV (r = 0.611, P < 0.0001) and acPWV (r = 0.384, P = 0.033) in thickened group. Moreover, CIMT showed stronger correlation with rcPWV than with acPWV in thickened group. Furthermore, both acPWV and rcPWV were determinant factors of CIMT in thickened group, independent of clinical confounders including age, gender, smoking behavior, systolic blood pressure, diastolic blood pressure, fasting blood glucose, total cholesterol, high-density lipoprotein cholesterol, antihypertensive medication, and plaque occurrence. However, similar results were not found in normal group. Since CIMT has been considered as an index of atherosclerosis, our results suggested that both rcPWV and acPWV could be useful indexes of atherosclerosis in thickened CIMT hypertensive patients. Additionally, if hcPWV is computed with heart-carotid pulse transit time, including PEP could improve the accuracy of atherosclerosis assessment in hypertensive patients. PMID:26705228

  10. A novel continuous cardiac output monitor based on pulse wave transit time.

    Science.gov (United States)

    Sugo, Yoshihiro; Ukawa, Teiji; Takeda, Sunao; Ishihara, Hironori; Kazama, Tomiei; Takeda, Junzo

    2010-01-01

    Monitoring cardiac output (CO) is important for the management of patient circulation in an operation room (OR) or intensive care unit (ICU). We assumed that the change in pulse wave transit time (PWTT) obtained from an electrocardiogram (ECG) and a pulse oximeter wave is correlated with the change in stroke volume (SV), from which CO is derived. The present study reports the verification of this hypothesis using a hemodynamic analysis theory and animal study. PWTT consists of a pre-ejection period (PEP), the pulse transit time through an elasticity artery (T(1)), and the pulse transit time through peripheral resistance arteries (T(2)). We assumed a consistent negative correlation between PWTT and SV under all conditions of varying circulatory dynamics. The equation for calculating SV from PWTT was derived based on the following procedures. 1. Approximating SV using a linear equation of PWTT. 2. The slope and y-intercept of the above equation were determined under consideration of vessel compliance (SV was divided by Pulse Pressure (PP)), animal type, and the inherent relationship between PP and PWTT. Animal study was performed to verify the above-mentioned assumption. The correlation coefficient of PWTT and SV became r = -0.710 (p 〈 0.001), and a good correlation was admitted. It has been confirmed that accurate continuous CO and SV measurement is only possible by monitoring regular clinical parameters (ECG, SpO2, and NIBP). PMID:21095971

  11. Influence of laser-supported detonation waves on metal drilling with pulsed CO2 lasers

    International Nuclear Information System (INIS)

    Drilling of highly reflective metals in an ambient atmosphere with single TEA-CO2-laser pulses of fluences between 300 and 6000 J/cm2 is reported. The drilling process was investigated by measuring the time-resolved laser power reflected specularly from the targets during the interaction and by analyzing the craters produced. Experiments were performed in ambient air, argon, and helium. Target damage was found to be strongly influenced by a laser-supported detonation (LSD) wave in the ambient gas. If the laser fluence exceeded a material-dependent damage threshold (copper: 300 J/cm2), drilling occurred, but the efficiency was inversely related to the duration of the LSD wave. Efficient material removal is possible if the LSD wave can be dissipated within a small fraction of the laser pulse duration. This was achieved by small-F-number focusing of TEM00 laser pulses of 5-μs duration. Replacing the ambient air at the target by a gas of lower density results in a further significant reduction of LSD-wave lifetime, and a correlated increase of the drilling yield. On copper targets a maximum drilling yield of 10-5 cm3/J was observed in ambient helium at a laser fluence of 1 kJ/cm2

  12. High resolution wavenumber analysis for investigation of arterial pulse wave propagation

    Science.gov (United States)

    Hasegawa, Hideyuki; Sato, Masakazu; Irie, Takasuke

    2016-07-01

    The propagation of the pulse wave along the artery is relatively fast (several m/s), and a high-temporal resolution is required to measure pulse wave velocity (PWV) in a regional segment of the artery. High-frame-rate ultrasound enables the measurement of the regional PWV. In analyses of wave propagation phenomena, the direction and propagation speed are generally identified in the frequency-wavenumber space using the two-dimensional Fourier transform. However, the wavelength of the pulse wave is very long (1 m at a propagation velocity of 10 m/s and a temporal frequency of 10 Hz) compared with a typical lateral field of view of 40 mm in ultrasound imaging. Therefore, PWV cannot be identified in the frequency-wavenumber space owing to the low resolution of the two-dimensional Fourier transform. In the present study, PWV was visualized in the wavenumber domain using phases of arterial wall acceleration waveforms measured by high-frame-rate ultrasound.

  13. Electromagnetic Pulse Generation by the Shock Wave of Explosion in the Ionosphere

    Science.gov (United States)

    Sorokin, V.; Sergeev, I.; Yaschenko, A.

    High-amplitude electric field pulses have been recorded during experiments with explosive injection in the ionosphere. Considerable electric field disturbances were observed in cases where the measurements were carried out near the same line of force of the geomagnetic field. Formation of the explosion shock wave electromagnetic field in the ionosphere is theoretically investigated. A shock wave arises in explosion - type active experiments and disasters of space engines at the ionospheric altitudes. A semi - empirical model of shock wave in the rarefied gas is constructed. This model enable to determine the spatial - temporal distribution of gas temperature, velocity, density and pressure between shock wave front and explosion product surface depend on the Mach number and the explosion altitude. In analyzing the electrodynamic processes accompanying the explosive injection it was assumed that their source is the electric current generated in a propagating shock wave. Electric current occurs by the ionosphere plasma perturbation in external magnetic field behind of the shock wave front. This current is a source of electromagnetic pulse in the ionospheric plasma with Pedersen and Hall conductivities. It is shown that the electromagnetic perturbation propagates along to the magnetic-field direction and has the form of an oscillating wave packet. The frequency of the wave packet decreases depends on time. Its characteristic group velocity, wave length, and frequency decrease depends on angle between the propagation direction and the external magnetic field. The characteristic frequency of oscillations varies from 0.1 - 10 Hz. The phase velocity decreases in the interval from 10 to 100 km/sec depends on distance from the source. As the angle increases, the oscillations disappear and the field propagates as a single-polarity pulse. Theoretical results have been compared with experimental data obtained by observations of electromagnetic phenomena during explosive

  14. On the pressure wave problem in liquid metal targets for pulsed spallation neutron sources

    International Nuclear Information System (INIS)

    A liquid metal target for a pulsed spallation source was modelled on the computer to investigate the effect of the high instantaneous power deposition (60 KJ in 1 μs) on the pressure in the liquid and the resulting stress on the container. It was found that for the short pulse duration the resulting stress would be likely to exceed the allowable design stress for steels of the HT-9 type with low nickel content. Adding a small volume fraction of gas bubbles might be a way to suppress almost completely the generation of pressure waves. (author) 12 figs., 5 refs

  15. Design of long-pulse fast wave current drive antennas for DIII-D

    Science.gov (United States)

    Baity, F. W.; Batchelor, D. B.; Bills, K. C.; Fogelman, C. H.; Jaeger, E. F.; Ping, J. L.; Riemer, B. W.; Ryan, P. M.; Stallings, D. C.; Taylor, D. J.; Yugo, J. J.

    1994-10-01

    Two new long-pulse fast wave current drive (FWCD) antennas will be installed on DIII-D in early 1994. These antennas will increase the available FWCD power from 2 MW to 6 MW for pulse lengths of up to 2 s, and to 4 MW for up to 10 s. Power for the new antennas is from two ASDEX-type 30- to 120-MHz transmitters. When operated at 90° phasing into a low-density plasma (˜4×1019m-3) with hot electrons (˜10 keV), these two new antennas are predicted to drive approximately 1 MA of plasma current.

  16. Electronic excitation by short X-ray pulses: From quantum beats to wave packet revivals

    CERN Document Server

    Riviere, Paula; Rost, Jan M

    2011-01-01

    We propose a simple way to determine the periodicities of wave packets in quantum systems directly from the energy differences of the states involved. The resulting classical periods and revival times are more accurate than those obtained with the traditional expansion of the energies about the central quantum number n, especially when n is low. The latter type of wave packet motion occurs upon excitation of highly charged ions with short XUV or X-ray pulses. Moreover, we formulate the wave packet dynamics in such a form that it directly reveals the origin of phase shifts in the maxima of the autocorrelation function. This phenomenon, so far poorly understood since it is not prominent in the high n regime, becomes a dominant feature in low n wave packet dynamics.

  17. Melting and shock wave creation in uranium oxide due to Coulomb explosion after a pulsed ionization

    International Nuclear Information System (INIS)

    By means of molecular dynamics simulations, we study the effects of pulsed ionization in uranium oxide (UO2), which occurs when UO2 is bombarded with swift ions or fission fragments. A general formula is developed to predict melting radius under various conditions due to electron stripping and Coulomb explosion (CE). A critical density model is suggested in which the melting volume is proportional to ionization period, if the period is above a critical value. The maximum melting radius depends on the time period of structural relaxation above the melting temperature, which increases with increasing initial substrate temperatures due to a lower heat dissipation rate. Furthermore, shock waves are observed to emit from CE core but the kinetic energy wave peak exists only in U sublattices. The absence of kinetic energy waves in O sublattices is explained by their relatively higher thermal vibration which cancels the work done from the compression waves

  18. Pulsed current wave shaping with a transmission line by utilizing superposition of a forward and a backward voltage wave for fast capillary Z-pinch discharge

    International Nuclear Information System (INIS)

    By using a water transmission line, current wave shaping was demonstrated for a fast capillary Z-pinch discharge recombination soft x-ray laser study. The pulsed power system consists of a water capacitor, a gap switch, a transmission line, and a capillary plasma load. A voltage wave initiated at the water capacitor propagates toward the capillary load through the transmission line. Control of the pulse delay that occurred in the transmission line provides the superposition of the forward and the backward voltage waves effectively in order to perform current wave shaping with higher current amplitude and rapid current decay.

  19. Generation of millimeter-wave sub-carrier optical pulse by using a Fabry-Perot interferometer

    Institute of Scientific and Technical Information of China (English)

    Qing Ye; Ronghui Qu; Zujie Fang

    2007-01-01

    A novel scheme is proposed to transform a Gaussian optical pulse to a millimeter-wave (mm-wave) frequency modulation pulse by using a Fabry-Perot interferometer (FPI) for radio-over-fiber (ROF) system.It is shown that modulation frequency of mm-wave is determined by the optical path of the Fabry-Perot (F-P) cavity, and amplitude decay time and energy transfer efficiency are related to the reflectivity of the F-P cavity mirror. The effect of pulse train extension on inter-symbol interference is also discussed.

  20. The decay of plane wave pulses with complex structure in a nonlinear dissipative medium

    CERN Document Server

    Gurbatov, S N; Pasmanik, G V; Gurbatov, Sergei N.; Enflo, Bengt O.; Pasmanik, Galina V.

    2000-01-01

    Nonlinear plane acoustic waves propagating through a fluid are studied using Burgers' equation with finite viscosity. The evolution of a simple N-pulse with regular and random initial amplitude and of pulses with monochromatic and noise carrier is considered. In the latter case the initial pulses are characterized by two length scales. The length scale of the modulation function is much greater than the period or the length scale of the carrier. With increasing time the initial pulses are deformed and shocks appear. The finite viscosity leads to a finite shock width, which does not depend on the fine structure of the initial pulse and is fully determined by the shock position in the zero viscosity limit. The other effect of nonzero viscosity is the shift of the shock position from the position at zero viscosity. This shift, as well as the linear time, at which the nonlinear stage of evolution changes to the linear stage, depends on the fine structure of the initial pulse. It is also shown that the nonlinearit...

  1. Millisecond polarized pulses in decameter-wave radiation from Jupiter and Sun

    International Nuclear Information System (INIS)

    A new approach is suggested to the problem of the theory of Jovian decametric radiation and physical conditions at the point of origin. This depends upon a comparison of the characteristics of fast pulse decametre-wave radio emission from both Jupiter and the Sun and invokes the deductive procedure which Sagan (1971) has called 'Propositional Calculus'. Fast polarized pulses in radiation from Jupiter and the Sun have been studied at fixed frequencies in the range 18 to 26 MHz with time resolutions from one to five msec; a number of similarities between the pulses from both sources have been noted. A comparison of some of the pulse characteristics is being made in order to decide whether or not they are sufficiently alike to be regarded as having a common mechanism of origin at both Jupiter and the Sun. From this 'decision' it is proposed to establish boundary conditions for theoretical study. Fast pulses in the Jupiter radiation are generally supposed to be a source phenomenon although their actual mechanism is not understood. The reasons for this are to some extent inferred rather than proven and so, to check the possible (if unlikely) role of the interplanetary medium, observations are also being made using the large 26 MHz array at the University of Florida to search for possible fast pulses in the radiation from the more distant source Taurus A. (Auth.)

  2. Dual pulses for cavitation control in lithotripsy: Shock wave-bubble interactions and bioeffects

    Science.gov (United States)

    Sokolov, Dahlia L.

    2002-08-01

    Cavitation, the growth and collapse of gas/vapor bubbles, appears to play an important role in both stone comminution and tissue injury during shock wave lithotripsy, the clinical treatment in which focused, high amplitude shock pulses are used to comminute kidney stones. The goal of this research was to characterize in vitro cavitation activity and stone and cell damage in a novel system that uses converging dual pulses, produced by two identical, confocal lithotripters, to modify the cavitation field. The cavitation bubble dynamics were numerically calculated, and experiments were performed in a research electrohydraulic shock wave lithotripter to determine bubble size, lifetime, and pit depth created in aluminum foils by cavitation collapse. Furthermore, damage to model stones and to red blood cells was measured for both single and dual-pulses. A single shock pulse creates a ˜15 x 100 mm cloud of bubbles in water. The greatest cavitation activity and stone damage from single-pulses was found to occur 2 cm proximal to the geometric focus, F2, where the stone is normally aligned. Therefore, a 2 cm shift in stone alignment may potentially improve stone comminution and reduce tissue injury in clinical treatment. The dual-pulse lithotripter, on the other hand, generates a localized and intensified cavitation field that increased stone comminution efficiency at F2 by at least three times the maximum values achieved by single-pulses. At F2, acoustic pressure approximately doubled, as did bubble size, collapse time, and pit depth on foils. A significant reduction in comminution of stones suspended in glycerol indicates that cavitation activity, not the doubling of acoustic pressure, explains the increased comminution. On either side of F2, the second delayed pulse mitigated bubble collapse, resulting in little or no pitting on foils and reduced hemolysis, even when compared with single pulses. Numerical calculations of radial dynamics agreed with experimental findings

  3. Numerical simulation of pressure waves in the cochlea induced by a microwave pulse.

    Science.gov (United States)

    Yitzhak, Nir M; Ruppin, Raphael; Hareuveny, Ronen

    2014-10-01

    The pressure waves developing at the cochlea by the irradiation of the body with a plane wave microwave pulse are obtained by numerical simulation, employing a two-step finite-difference time-domain (FDTD) algorithm. First, the specific absorption rate (SAR) distribution is obtained by solving the Maxwell equations on a FDTD grid. Second, the temperature rise due to this SAR distribution is used to formulate the thermoelastic equations of motion, which are discretized and solved by the FDTD method. The calculations are performed for anatomically based full body human models, as well as for a head model. The dependence of the pressure amplitude at the cochlea on the frequency, the direction of propagation, and the polarization of the incident electromagnetic radiation, as well as on the pulse width, was investigated.

  4. Determination of Bosentan in Pharmaceutical Preparations by Linear Sweep, Square Wave and Differential Pulse Voltammetry Methods

    OpenAIRE

    Atila, Alptug; Yilmaz, Bilal

    2015-01-01

    In this study, simple, fast and reliable cyclic voltammetry (CV), linear sweep voltammetry (LSV), square wave voltammetry (SWV) and differential pulse voltammetry (DPV) methods were developed and validated for determination of bosentan in pharmaceutical preparations. The proposed methods were based on electrochemical oxidation of bosentan at platinum electrode in acetonitrile solution containing 0.1 M TBACIO4. The well-defined oxidation peak was observed at 1.21 V. The calibration curves were...

  5. A new flow co-culture system for studying mechanobiology effects of pulse flow waves

    OpenAIRE

    Scott-Drechsel, Devon; Su, Zhenbi; Hunter, Kendall; Li, Min; Shandas, Robin; Tan, Wei

    2012-01-01

    Artery stiffening is known as an important pathological change that precedes small vessel dysfunction, but underlying cellular mechanisms are still elusive. This paper reports the development of a flow co-culture system that imposes a range of arterial-like pulse flow waves, with similar mean flow rate but varied pulsatility controlled by upstream stiffness, onto a 3-D endothelial-smooth muscle cell co-culture. Computational fluid dynamics results identified a uniform flow area critical for c...

  6. Two-photon vibrational excitation of air by long-wave infrared laser pulses

    OpenAIRE

    Palastro, J. P.; Penano, J.; Johnson, L A; Hafizi, B.; Wahlstrand, J. K.; Milchberg, H. M.

    2016-01-01

    Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a two-photon transition. The absorptive, vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than, but quickly surpassing, the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanism of 3rd harmonic generation, providing an additional two-photon excitation channel, fundamental...

  7. Temporal Skewness of Electromagnetic Pulsed Waves Propagating Through Random Media with Embedded Irregularity Slab

    Institute of Scientific and Technical Information of China (English)

    许正文; 吴健; 霍文平; 吴振森

    2003-01-01

    Electromagnetic pulsed waves can be distorted in the propagation through random media, and their energy dis tributions change along the leading and trailing edge of the waveform, which can be presented by the temporal skewness. The skewness presents asymmetry and is treated by the third-order temporal moment, in which an analytic solution for the two-frequency mutual coherence function is obtained recently. Then, transionospheric pulses are discussed in details. Both theoretical analysis and numerical computation indicate that the contri butions from scattering and dispersion of irregularities dominate over those of background, so the latter can be neglected in most cases. Also, the temporal skewness of a transionospheric pulse is negative and energy is shifted to the leading edge.

  8. Numerical studies of powerful terahertz pulse generation from a super-radiant surface wave oscillator

    International Nuclear Information System (INIS)

    The results of theoretical and numerical studies of coherent stimulated terahertz radiation from intense, subnanosecond electron beam are presented. The mechanism of terahertz pulse generation is associated with self-bunching of the beam and slippage of the wave over the whole electron flow. This so called Cherenkov super-radiance (SR) is used to propose a compact terahertz generator with high peak power. A large cross-section (overmoded), slow wave structure is designed to support the high power handling capability, and the mode competition is avoided by operating the device in the surface wave status. With 2.5 D particle-in-cell simulation, the 'hot' characteristics of the proposed super-radiant terahertz generator are investigated, and the numerical results show that the SR peak power could be further increased by optimizing the amplitude profile of electron pulse. Under the condition of 0.5 ns pulsewidth, 500 kV voltage, and 1.5 kA current, the 110 ps, 680 MW, and 0.14 THz SR pulse is achieved with a power efficiency of 90.67% in TM01 mode.

  9. Estimation of local pulse wave velocity using arterial diameter waveforms: Experimental validation in sheep

    Science.gov (United States)

    Graf, S.; Craiem, D.; Barra, J. G.; Armentano, R. L.

    2011-12-01

    Increased arterial stiffness is associated with an increased risk of cardiovascular events. Estimation of arterial stiffness using local pulse wave velocity (PWV) promises to be very useful for noninvasive diagnosis of arteriosclerosis. In this work we estimated in an instrumented sheep, the local aortic pulse wave velocity using two sonomicrometry diameter sensors (separated 7.5 cm) according to the transit time method (PWVTT) with a sampling rate of 4 KHz. We simultaneously measured aortic pressure in order to determine from pressure-diameter loops (PWVPDLoop), the "true" local aortic pulse wave velocity. A pneumatic cuff occluder was implanted in the aorta in order to compare both methods under a wide range of pressure levels. Mean pressure values ranged from 47 to 101 mmHg and mean proximal diameter values from 12.5. to 15.2 mm. There were no significant differences between PWVTT and PWVPDLoop values (451±43 vs. 447±48 cm/s, p = ns, paired t-test). Both methods correlated significantly (R = 0.81, p<0.05). The mean difference between both methods was only -4±29 cm/s, whereas the range of the limits of agreement (mean ± 2 standard deviation) was -61 to +53 cm/s, showing no trend. In conclusion, the diameter waveforms transit time method was found to allow an accurate and precise estimation of the local aortic PWV.

  10. Correlates of Osteoprotegerin and Association with Aortic Pulse Wave Velocity in Patients with Chronic Kidney Disease

    Science.gov (United States)

    Leonard, Mary B.; Townsend, Raymond R.; Appel, Lawrence; Wolf, Myles; Budoff, Matt J.; Chen, Jing; Lustigova, Eva; Gadegbeku, Crystal A.; Glenn, Melanie; Hanish, Asaf; Raj, Dominic; Rosas, Sylvia E.; Seliger, Stephen L.; Weir, Matthew R.; Parekh, Rulan S.

    2011-01-01

    Summary Background and objectives Osteoprotegerin (OPG), a cytokine that regulates bone resorption, has been implicated in the process of vascular calcification and stiffness. Design, setting, participants, & measurements Serum OPG was measured in 351 participants with chronic kidney disease (CKD) from one site of the Chronic Renal Insufficiency Cohort Study. Cortical bone mineral content (BMC) was measured by quantitative computed tomography in the tibia. Multivariable linear regression was used to test the association between serum OPG and traditional cardiovascular risk factors, measures of abnormal bone and mineral metabolism, and pulse wave velocity. Results Higher serum OPG levels were associated with older age, female gender, greater systolic BP, lower estimated GFR, and lower serum albumin. OPG was not associated with measures of abnormal bone or mineral metabolism including serum phosphorus, albumin-corrected serum calcium, intact parathyroid hormone, bone-specific alkaline phosphatase, or cortical BMC. Among 226 participants with concurrent aortic pulse wave velocity measurements, increasing tertiles of serum OPG were associated with higher aortic pulse wave velocity after adjustment for demographics, traditional vascular risk factors, and nontraditional risk factors such as estimated GFR, albuminuria, serum phosphate, corrected serum calcium, presence of secondary hyperparathyroidism, serum albumin, and C-reactive protein or after additional adjustment for cortical BMC in a subset (n = 161). Conclusions These data support a strong relationship between serum OPG and arterial stiffness independent of many potential confounders including traditional cardiovascular risk factors, abnormal bone and mineral metabolism, and inflammation. PMID:21940840

  11. Estimation of local pulse wave velocity using arterial diameter waveforms: Experimental validation in sheep

    International Nuclear Information System (INIS)

    Increased arterial stiffness is associated with an increased risk of cardiovascular events. Estimation of arterial stiffness using local pulse wave velocity (PWV) promises to be very useful for noninvasive diagnosis of arteriosclerosis. In this work we estimated in an instrumented sheep, the local aortic pulse wave velocity using two sonomicrometry diameter sensors (separated 7.5 cm) according to the transit time method (PWVTT) with a sampling rate of 4 KHz. We simultaneously measured aortic pressure in order to determine from pressure-diameter loops (PWVPDLoop), the true local aortic pulse wave velocity. A pneumatic cuff occluder was implanted in the aorta in order to compare both methods under a wide range of pressure levels. Mean pressure values ranged from 47 to 101 mmHg and mean proximal diameter values from 12.5. to 15.2 mm. There were no significant differences between PWVTT and PWVPDLoop values (451±43 vs. 447±48 cm/s, p = ns, paired t-test). Both methods correlated significantly (R = 0.81, p<0.05). The mean difference between both methods was only 4±29 cm/s, whereas the range of the limits of agreement (mean ± 2 standard deviation) was -61 to +53 cm/s, showing no trend. In conclusion, the diameter waveforms transit time method was found to allow an accurate and precise estimation of the local aortic PWV.

  12. Dynamics of pulses and spiral waves in excitable media with an anomalous diffusion

    Science.gov (United States)

    Yuan, Guoyong; Bao, Xueping; Yang, Shiping; Wang, Guangrui; Chen, Shaoying

    2016-06-01

    Spiral waves and pulses in the excitable medium with an anomalous diffusion are studied. In the medium with an one-sided fractional diffusion in the x-direction and a normal diffusion in the y-direction, a pulse, traveling along the positive x-direction, has a smaller velocity, which is different from the diffusion of a source in the other media. Its propagating velocity is a linear and increasing function of the square root of diffusion parameter, whose increasing rate depends on the fractional order. A minimal value of the diffusion parameter is needed for successfully propagating pulses, and the threshold becomes large with a decrease of the fractional order. For pulse trains, the frequency-locked bands are shifted along the increasing direction of the perturbation period when the fractional order is decreased. In the propagating process of a spiral wave, the tip drift is induced by the one-sided fractional diffusion, which may be explained by analyzing the SV area in front of the tip.

  13. Microjoule sub-10 fs VUV pulse generation by MW pump pulses using highly efficient chirped four-wave mixing in hollow-core photonic crystal fibers

    Science.gov (United States)

    Im, Song-Jin

    2015-03-01

    We theoretically study chirped four-wave mixing for VUV pulse generation in hollow-core photonic crystal fibers. We predict the generation of sub-10 fs VUV pulses with energy of up to hundreds of µJ by broad-band chirped idler pulses at 830 nm and MW pump pulses with narrow-band at 277 nm. The MW pump could be desirable to reduce the complexity of the laser system or use a high repetition rate laser system. The energy conversion efficiency from pump pulse to VUV pulse reaches to 30% . This generation can be realized in a kagome-lattice hollow-core PCF filled with noble gas of high pressure with core diameter less than 40 µm, which would enable technically simple or highly efficient coupling to the fundamental mode of the fiber.

  14. Micro-joule sub-10-fs VUV pulse generation by MW pump pulse using highly efficient chirped-four-wave mixing in hollow-core photonic crystal fibers

    CERN Document Server

    Im, Song-Jin

    2013-01-01

    We theoretically study chirped four-wave mixing for VUV pulse generation in hollow-core photonic crystal fibers. We predict the generation of sub-10-fs VUV pulses with energy of up to hundreds of microjoule by broad-band chirped idler pulses at 830 nm and MW pump pulses with narrow-band at 277 nm. MW pump could be desirable to reduce the complexity of the laser system or use a high repetition rate-laser system. The energy conversion efficiency from pump pulse to VUV pulse reaches to 30%. This generation can be realized in kagome-lattice hollow-core PCF filled with noble gas of high pressure with core-diameter less than 40 micrometers which would enable technically simple or highly efficient coupling to fundamental mode of the fiber.

  15. Continuous reversal of Hanle resonances of counter-propagating pulse and continuous-wave field

    CERN Document Server

    Dimitrijević, Jelena; Jelenković, Branislav M

    2013-01-01

    In this work we study propagation dynamics of the two counter-propagating lasers, the continuous-wave (CW) laser and the pulse of another laser, when both lasers are tuned to the $F_{g}=2 \\rightarrow F_{e}=1$ transition in $^{87}$Rb, and therefore can develop Hanle electromagnetically induced transparency (EIT) in Rb vapor. We calculate transmission of both lasers as a function of applied magnetic field, and investigate how the propagation of the pulse affects the transmission of the CW laser. And vice versa, we have found conditions when the Gaussian pulse can either pass unchanged, or be significantly absorbed in the vacuum Rb cell. This configuration is therefore suitable for the convenient control of the pulse propagation and the system is of interest for optically switching of the laser pulses. In terms of the corresponding shapes of the coherent Hanle resonances, this is equivalent to turning the coherent resonance from Hanle EIT into electromagnetically induced absorption (EIA) peak. There is the range...

  16. High-power Yb-doped continuous-wave and pulsed fibre lasers

    Indian Academy of Sciences (India)

    B N Upadhyaya

    2014-01-01

    High-power laser generation using Yb-doped double-clad fibres with conversion efficiencies in excess of 80% have attracted much attention during the last decade due to their inherent advantages in terms of very high efficiency, no misalignment due to in-built intracore fibre Bragg gratings, low thermal problems due to large surface to volume ratio, diffraction-limited beam quality, compactness, reliability and fibre-optic beam delivery. Yb-doped fibres can also provide a wide emission band from ∼1010 nm to ∼1170 nm, which makes it a versatile laser medium to realize continuous-wave (CW), Q-switched short pulse, and mode-locked ultrashort pulse generation for various applications. In this article, a review of Yb-doped CW and pulsed fibre lasers along with our study on self-pulsing dynamics in CW fibre lasers to find its role in high-power fibre laser development and the physical mechanisms involved in its generation has been described. A study on the generation of high-power CWfibre laser of 165Woutput power and generation of high peak power nanosecond pulses from acousto-optic Q-switched fibre laser has also been presented.

  17. Lifetime risk factors and arterial pulse wave velocity in adulthood: the cardiovascular risk in young Finns study.

    Science.gov (United States)

    Aatola, Heikki; Hutri-Kähönen, Nina; Juonala, Markus; Viikari, Jorma S A; Hulkkonen, Janne; Laitinen, Tomi; Taittonen, Leena; Lehtimäki, Terho; Raitakari, Olli T; Kähönen, Mika

    2010-03-01

    Limited and partly controversial data are available regarding the relationship of arterial pulse wave velocity and childhood cardiovascular risk factors. We studied how risk factors identified in childhood and adulthood predict pulse wave velocity assessed in adulthood. The study cohort consisted of 1691 white adults aged 30 to 45 years who had risk factor data available since childhood. Pulse wave velocity was assessed noninvasively by whole-body impedance cardiography. The number of conventional childhood and adulthood risk factors (extreme quintiles for low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, systolic blood pressure, body mass index, and smoking) was directly associated with pulse wave velocity in adulthood (P=0.005 and P<0.0001, respectively). In multivariable regression analysis, independent predictors of pulse wave velocity were sex (P<0.0001), age (P<0.0001), childhood systolic blood pressure (P=0.002) and glucose (P=0.02), and adulthood systolic blood pressure (P<0.0001), insulin (P=0.0009), and triglycerides (P=0.003). Reduction in the number of risk factors (P<0.0001) and a favorable change in obesity status (P=0.0002) from childhood to adulthood were associated with lower pulse wave velocity in adulthood. Conventional risk factors in childhood and adulthood predict pulse wave velocity in adulthood. Favorable changes in risk factor and obesity status from childhood to adulthood are associated with lower pulse wave velocity in adulthood. These results support efforts for a reduction of conventional risk factors both in childhood and adulthood in the primary prevention of atherosclerosis. PMID:20083727

  18. Effects of continuous-wave, pulsed, and sinusoidal-amplitude-modulated microwaves on brain energy metabolism.

    Science.gov (United States)

    Sanders, A P; Joines, W T; Allis, J W

    1985-01-01

    A comparison of the effects of continuous-wave, sinusoidal-amplitude-modulated, and pulsed square-wave-modulated 591-MHz microwave exposures on brain energy metabolism was made in male Sprague-Dawley rats (175-225 g). Brain NADH fluorescence, adenosine triphosphate (ATP) concentration, and creatine phosphate (CP) concentration were determined as a function of modulation frequency. Brain temperatures of animals were maintained between -0.1 and -0.4 degrees C from the preexposure temperature when subjected to as much as 20 mW/cm2 (average power) CW, pulsed, or sinusoidal-amplitude modulated 591-MHz radiation for 5 min. Sinusoidal-amplitude-modulated exposures at 16-24 Hz showed a trend toward preferential modulation frequency response in inducing an increase in brain NADH fluorescence. The pulse-modulated and sinusoidal-amplitude-modulated (16 Hz) microwaves were not significantly different from CW exposures in inducing increased brain NADH fluorescence and decreased ATP and CP concentrations. When the pulse-modulation frequency was decreased from 500 to 250 pulses per second the average incident power density threshold for inducing an increase in brain NADH fluorescence increased by a factor of 4--ie, from about 0.45 to about 1.85 mW/cm2. Since brain temperature did not increase, the microwave-induced increase in brain NADH and decrease in ATP and CP concentrations was not due to hyperthermia. This suggests a direct interaction mechanism and is consistent with the hypothesis of microwave inhibition of mitochondrial electron transport chain function of ATP production.

  19. 2, Pulse-mode expansions and refractive indices in plane-wave propagation

    Energy Technology Data Exchange (ETDEWEB)

    Shore, B.W.; Sacks, R.; Karr, T.; Morris, J.; Paisner, J.A.

    1987-06-20

    This memo presents basic background theory for treating simultaneous propagation of electromagnetic pulses of various colors, directed along a common ray, through a molecular vapor. The memo discusses some techniques for expanding the positive frequency part of the transverse electric field into pulse modes, characterized by carrier frequencies within a modulated envelope. We discuss, in the approximation of plane waves with slowly varying envelopes, a set of uncoupled envelope equations in which a polarization mode-envelope acts as a source for an electric-field envelope. These equations, when taken with a prescription for the polarization field, are the basic equations of plane-wave pulse propagation through a molecular medium. We discuss two ways of treating dispersive media, one based upon expansions in the frequency domain and the other based in the time domain. In both cases we find envelope equations that involve group velocities. This memo represents a portion of a more extensive treatment of propagation to be presented separately. Many of the equations presented here have been described in various books and articles. They are collected and described here as a summary and review of contemporary theory.

  20. Feedback Interactions of Polymerized Actin with the Cell Membrane: Waves, Pulses, and Oscillations

    Science.gov (United States)

    Carlsson, Anders

    Polymerized filaments of the protein actin have crucial functions in cell migration, and in bending the cell membrane to drive endocytosis or the formation of protrusions. The nucleation and polymerization of actin filaments are controlled by upstream agents in the cell membrane, including nucleation-promoting factors (NPFs) that activate the Arp2/3 complex to form new branches on pre-existing filaments. But polymerized actin (F-actin) also feeds back on the assembly of NPFs. We explore the effects of the resulting feedback loop of F-actin and NPFs on two phenomena: actin pulses that drive endocytosis in yeast, and actin waves traveling along the membrane of several cell types. In our model of endocytosis in yeast, the actin network is grown explicitly in three dimensions, exerts a negative feedback interaction on localized patch of NPFs in the membrane, and bends the membrane by exerting a distribution of forces. This model explains observed actin and NPF pulse dynamics, and the effects of several interventions including i) NPF mutations, ii) inhibition of actin polymerization, and iii) deletion of a protein that allows F-actin to bend the cell membrane. The model predicts that mutation of the active region of an NPF will enhance the accumulation of that NPF, and we confirm this prediction by quantitative fluorescence microscopy. For actin waves, we treat a similar model, with NPFs distributed over a larger region of the cell membrane. This model naturally generates actin waves, and predicts a transition from wave behavior to spatially localized oscillations when NPFs are confined to a small region. We also predict a transition from waves to static polarization as the negative-feedback coupling between F-actin and the NPFs is reduced. Supported by NIGMS Grant R01 GM107667.

  1. Pulse-driven nonlinear Alfv\\'en waves and their role in the spectral line broadening

    CERN Document Server

    Chmielewski, P; Murawski, K; Musielak, Z E

    2012-01-01

    We study the impulsively generated non-linear Alfv\\'en waves in the solar atmosphere, and describe their most likely role in the observed non-thermal broadening of some spectral lines in solar coronal holes. We solve numerically the time-dependent magnetohydrodynamic equations to find temporal signatures of large-amplitude Alfv\\'en waves in the model atmosphere of open and expanding magnetic field configuration, with a realistic temperature distribution. We calculate the temporally and spatially averaged, instantaneous transversal velocity of non-linear Alfv\\'en waves at different heights of the model atmosphere, and estimate its contribution to the unresolved non-thermal motions caused by the waves. We find that the pulse-driven nonlinear Alfv\\'en waves with the amplitude $A_{\\rm v}$=50 km s$^{-1}$ are the most likely candidates for the non-thermal broadening of Si VIII $\\lambda$1445.75 \\AA\\ line profiles in the polar coronal hole as reported by Banerjee et al. (1998). We also demonstrate that the Alfv\\'en w...

  2. Effect of heat-induced pain stimuli on pulse transit time and pulse wave amplitude in healthy volunteers.

    Science.gov (United States)

    van Velzen, Marit H N; Loeve, Arjo J; Kortekaas, Minke C; Niehof, Sjoerd P; Mik, Egbert G; Stolker, Robert J

    2016-01-01

    Pain is commonly assessed subjectively by interpretations of patient behaviour and/or reports from patients. When this is impossible the availability of a quantitative objective pain assessment tool based on objective physiological parameters would greatly benefit clinical practice and research beside the standard self-report tests. Vasoconstriction is one of the physiological responses to pain. The aim of this study was to investigate whether pulse transit time (PTT) and pulse wave amplitude (PWA) decrease in response to this vasoconstriction when caused by heat-induced pain. The PTT and PWA were measured in healthy volunteers, on both index fingers using photoplethysmography and electrocardiography. Each subject received 3 heat-induced pain stimuli using a Temperature-Sensory Analyzer thermode block to apply a controlled, increasing temperature from 32.0 °C to 50.0 °C to the skin. After reaching 50.0 °C, the thermode was immediately cooled down to 32.0 °C. The study population was divided into 2 groups with a time-interval between the stimuli 20s or 60s. The results showed a significant (p  <  0.05) decrease of both PTT and PWA on the stimulated and contralateral side. Moreover, there was no significant difference between the stimulated and contralateral side. The time-interval of 20s was too short to allow PTT and PWA to return to baseline values and should exceed 40s in future studies. Heat-induced pain causes a decrease of PTT and PWA. Consequently, it is expected that, in the future, PTT and PWA may be applied as objective indicators of pain, either beside the standard self-report test, or when self-report testing is impossible.

  3. Detection and Characterization of Flaws in Sprayed on Foam Insulation with Pulsed Terahertz Frequency Electromagnetic Waves

    Science.gov (United States)

    Winfree, William P.; Madaras, Eric I.

    2005-01-01

    The detection and repair of flaws such as voids and delaminations in the sprayed on foam insulation of the external tank reduces the probability of foam debris during shuttle ascent. The low density of sprayed on foam insulation along with it other physical properties makes detection of flaws difficult with conventional techniques. An emerging technology that has application for quantitative evaluation of flaws in the foam is pulsed electromagnetic waves at terahertz frequencies. The short wavelengths of these terahertz pulses make them ideal for imaging flaws in the foam. This paper examines the application of terahertz pulses for flaw detection in foam characteristic of the foam insulation of the external tank. Of particular interest is the detection of voids and delaminations, encapsulated in the foam or at the interface between the foam and a metal backing. The technique is shown to be capable of imaging small voids and delaminations through as much as 20 cm of foam. Methods for reducing the temporal responses of the terahertz pulses to improve flaw detection and yield quantitative characterizations of the size and location of the flaws are discussed.

  4. Two-photon vibrational excitation of air by long-wave infrared laser pulses

    Science.gov (United States)

    Palastro, J. P.; Peñano, J.; Johnson, L. A.; Hafizi, B.; Wahlstrand, J. K.; Milchberg, H. M.

    2016-08-01

    Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a two-photon transition. The absorptive vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than but quickly surpassing the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanism of third-harmonic generation, providing an additional two-photon excitation channel, fundamental + third harmonic. The original and emergent two-photon excitations drive the resonance exactly out of phase, causing spatial decay of the absorptive vibrational nonlinearity. This nearly eliminates two-photon vibrational absorption. Here we present simulations and analytical calculations demonstrating how these processes modify the ultrafast optical nonlinearity in air. The results reveal nonlinear optical phenomena unique to the LWIR regime of ultrashort pulse propagation in the atmosphere.

  5. Pulsed plane wave analytic solutions for generic shapes and the validation of Maxwell's equations solvers

    Science.gov (United States)

    Yarrow, Maurice; Vastano, John A.; Lomax, Harvard

    1992-01-01

    Generic shapes are subjected to pulsed plane waves of arbitrary shape. The resulting scattered electromagnetic fields are determined analytically. These fields are then computed efficiently at field locations for which numerically determined EM fields are required. Of particular interest are the pulsed waveform shapes typically utilized by radar systems. The results can be used to validate the accuracy of finite difference time domain Maxwell's equations solvers. A two-dimensional solver which is second- and fourth-order accurate in space and fourth-order accurate in time is examined. Dielectric media properties are modeled by a ramping technique which simplifies the associated gridding of body shapes. The attributes of the ramping technique are evaluated by comparison with the analytic solutions.

  6. Design of broadband transmission quarter-wave plates for polarization control of isolated attosecond pulses

    International Nuclear Information System (INIS)

    Using a standard Levenberg–Marquardt algorithm, broadband quarter-wave plates (QWPs) with bandwidth from 3 to 18 eV in the extreme ultraviolet (EUV) region were designed using aperiodic Mo/Si multilayers. By analyzing the design results of the Mo/Si multiayers with different bilayer numbers, we found that a Mo/Si multilayer with more bilayers can achieve broader phase control, but suffers from lower total throughput and a degree of circular polarization. In addition, the pulse broadenings caused by the group delay dispersions of the designed broadband QWPs were studied, and their layer distributions were investigated. The oscillating distribution of bilayer thickness in optimized multilayers was observed, which is considered to be the reason for forming the broadband phase control. Such broadband QWPs can be applied to generate a circularly polarized broadband EUV source, such as isolated attosecond pulse, directly from a linearly polarized source. (paper)

  7. Studies on an improved indigenous pressure wave generator and its testing with a pulse tube cooler

    Science.gov (United States)

    Jacob, S.; Karunanithi, R.; Narsimham, G. S. V. L.; Kranthi, J. Kumar; Damu, C.; Praveen, T.; Samir, M.; Mallappa, A.

    2014-01-01

    Earlier version of an indigenously developed Pressure Wave Generator (PWG) could not develop the necessary pressure ratio to satisfactorily operate a pulse tube cooler, largely due to high blow by losses in the piston cylinder seal gap and due to a few design deficiencies. Effect of different parameters like seal gap, piston diameter, piston stroke, moving mass and the piston back volume on the performance is studied analytically. Modifications were done to the PWG based on analysis and the performance is experimentally measured. A significant improvement in PWG performance is seen as a result of the modifications. The improved PWG is tested with the same pulse tube cooler but with different inertance tube configurations. A no load temperature of 130 K is achieved with an inertance tube configuration designed using Sage software. The delivered PV power is estimated to be 28.4 W which can produce a refrigeration of about 1 W at 80 K.

  8. Design Concepts For A Long Pulse Upgrade For The DIII-D Fast Wave Antenna Array

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, Philip Michael [ORNL; Baity Jr, F Wallace [ORNL; Caughman, John B [ORNL; Goulding, Richard Howell [ORNL; Hosea, J. [Princeton Plasma Physics Laboratory (PPPL); Greenough, Nevell [Princeton Plasma Physics Laboratory (PPPL); Nagy, Alex [Princeton Plasma Physics Laboratory (PPPL); Pinsker, R. [General Atomics; Rasmussen, David A [ORNL

    2009-01-01

    A goal in the 5-year plan for the fast wave program on DIII-D is to couple a total of 3.6 MW of RF power into a long pulse, H-mode plasma for central electron heating. The present short-pulse 285/300 antenna array would need to be replaced with one capable of at least 1.2 MW, 10 s operation at 60 MHz into an H-mode (low resistive loading) plasma condition. The primary design under consideration uses a poloidally-segmented strap (3 sections) for reduced strap voltage near the plasma/Faraday screen region. Internal capacitance makes the antenna structure self-resonant at 60 MHz, strongly reducing peak E-fields in the vacuum coax and feed throughs.

  9. Arterial pulse pressure amplification described by means of a nonlinear wave model: characterization of human aging

    Science.gov (United States)

    Alfonso, M.; Cymberknop, L.; Armentano, R.; Pessana, F.; Wray, S.; Legnani, W.

    2016-04-01

    The representation of blood pressure pulse as a combination of solitons captures many of the phenomena observed during its propagation along the systemic circulation. The aim of this work is to analyze the applicability of a compartmental model for propagation regarding the pressure pulse amplification associated with arterial aging. The model was applied to blood pressure waveforms that were synthesized using solitons, and then validated by waveforms obtained from individuals from differentiated age groups. Morphological changes were verified in the blood pressure waveform as a consequence of the aging process (i.e. due to the increase in arterial stiffness). These changes are the result of both a nonlinear interaction and the phenomena present in the propagation of nonlinear mechanic waves.

  10. Design of long-pulse fast wave current drive antennas for DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Baity, F.W.; Batchelor, D.B.; Bills, K.C.; Fogelman, C.H.; Jaeger, E.F.; Ping, J.L.; Riemer, B.W.; Ryan, P.M.; Stallings, D.C.; Taylor, D.J.; Yugo, J.J. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (United States))

    1994-10-15

    Two new long-pulse fast wave current drive (FWCD) antennas will be installed on DIII-D in early 1994. These antennas will increase the available FWCD power from 2 MW to 6 MW for pulse lengths of up to 2 s, and to 4 MW for up to 10 s. Power for the new antennas is from two ASDEX-type 30- to 120-MHz transmitters. When operated at 90[degree] phasing into a low-density plasma ([similar to]4[times]10[sup 19]m[sup [minus]3]) with hot electrons ([similar to]10 keV), these two new antennas are predicted to drive approximately 1 MA of plasma current.

  11. Two-photon vibrational excitation of air by long-wave infrared laser pulses

    CERN Document Server

    Palastro, J P; Johnson, L A; Hafizi, B; Wahlstrand, J K; Milchberg, H M

    2016-01-01

    Ultrashort long-wave infrared (LWIR) laser pulses can resonantly excite vibrations in N2 and O2 through a two-photon transition. The absorptive, vibrational component of the ultrafast optical nonlinearity grows in time, starting smaller than, but quickly surpassing, the electronic, rotational, and vibrational refractive components. The growth of the vibrational component results in a novel mechanism of 3rd harmonic generation, providing an additional two-photon excitation channel, fundamental + 3rd harmonic. The original and emergent two-photon excitations drive the resonance exactly out of phase, causing spatial decay of the absorptive, vibrational nonlinearity. This nearly eliminates two-photon vibrational absorption. Here we present simulations and analytical calculations demonstrating how these processes modify the ultrafast optical nonlinearity in air. The results reveal nonlinear optical phenomena unique to the LWIR regime of ultrashort pulse propagation in atmosphere.

  12. Kinetic Monte Carlo simulations of travelling pulses and spiral waves in the lattice Lotka-Volterra model.

    Science.gov (United States)

    Makeev, Alexei G; Kurkina, Elena S; Kevrekidis, Ioannis G

    2012-06-01

    Kinetic Monte Carlo simulations are used to study the stochastic two-species Lotka-Volterra model on a square lattice. For certain values of the model parameters, the system constitutes an excitable medium: travelling pulses and rotating spiral waves can be excited. Stable solitary pulses travel with constant (modulo stochastic fluctuations) shape and speed along a periodic lattice. The spiral waves observed persist sometimes for hundreds of rotations, but they are ultimately unstable and break-up (because of fluctuations and interactions between neighboring fronts) giving rise to complex dynamic behavior in which numerous small spiral waves rotate and interact with each other. It is interesting that travelling pulses and spiral waves can be exhibited by the model even for completely immobile species, due to the non-local reaction kinetics.

  13. Kinetic Monte Carlo simulations of travelling pulses and spiral waves in the lattice Lotka-Volterra model

    Science.gov (United States)

    Makeev, Alexei G.; Kurkina, Elena S.; Kevrekidis, Ioannis G.

    2012-06-01

    Kinetic Monte Carlo simulations are used to study the stochastic two-species Lotka-Volterra model on a square lattice. For certain values of the model parameters, the system constitutes an excitable medium: travelling pulses and rotating spiral waves can be excited. Stable solitary pulses travel with constant (modulo stochastic fluctuations) shape and speed along a periodic lattice. The spiral waves observed persist sometimes for hundreds of rotations, but they are ultimately unstable and break-up (because of fluctuations and interactions between neighboring fronts) giving rise to complex dynamic behavior in which numerous small spiral waves rotate and interact with each other. It is interesting that travelling pulses and spiral waves can be exhibited by the model even for completely immobile species, due to the non-local reaction kinetics.

  14. The pioneer in hemodynamics and pulse-wave analysis, Otto Frank.

    Science.gov (United States)

    Middeke, Martin

    2016-04-01

    Arterial pulse-wave velocity is a noninvasive index of arterial distensibility now generally advocated to assess cardiovascular health above-and-beyond merely measuring blood pressure. A host of recent findings supports its use. This evidence draws attention to the fact that vascular stiffness precedes the increase in blood pressure with age and that even nonpharmacological lifestyle interventions can improve distensibility independent of blood pressure. Where do these ingeniously modern ideas come from, and who defined the principles we embrace today? A worthwhile lesson in physiology and exercise in humility is the effort to revisit the origins of these concepts and the man to whom gratitude should be directed. PMID:27068436

  15. Dissipative rogue wave generation in multiple-pulsing mode-locked fiber laser

    Science.gov (United States)

    Lecaplain, C.; Grelu, Ph; Soto-Crespo, J. M.; Akhmediev, N.

    2013-06-01

    Following the first experimental observation of a new mechanism leading to optical rogue wave (RW) formation briefly reported in Lecaplain et al (2012 Phys. Rev. Lett. 108 233901), we provide an extensive study of the experimental conditions under which these RWs can be detected. RWs originate from the nonlinear interactions of bunched chaotic pulses that propagate in a fiber laser cavity, and manifest as rare events of high optical intensity. The crucial influence of the electrical detection bandwidth is illustrated. We also clarify the observation of RWs with respect to other pulsating regimes, such as Q-switching instability, that also lead to L-shaped probability distribution functions.

  16. A method for localized computation of Pulse Wave Velocity in carotid structure.

    Science.gov (United States)

    Patil, Ravindra B; Krishnamoorthy, P; Sethuraman, Shriram

    2015-08-01

    Pulse Wave Velocity (PWV) promises to be a useful clinical marker for noninvasive diagnosis of atherosclerosis. This work demonstrates the ability to perform localized carotid PWV measurements from the distention waveform derived from the Radio Frequency (RF) ultrasound signal using a carotid phantom setup. The proposed system consists of low cost custom-built ultrasound probe and algorithms for envelope detection, arterial wall identification, echo tracking, distension waveform computation and PWV estimation. The method is proposed on a phantom data acquired using custom-built prototype non-imaging probe. The proposed approach is non-image based and can be seamlessly integrated into existing clinical ultrasound scanners. PMID:26736653

  17. Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers

    International Nuclear Information System (INIS)

    We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs

  18. Soliton radiation beat analysis of optical pulses generated from two continuous-wave lasers

    Energy Technology Data Exchange (ETDEWEB)

    Zajnulina, M.; Giannone, D.; Haynes, R.; Roth, M. M. [innoFSPEC-VKS, Leibniz Institute for Astrophysics, An der Sternwarte 16, 14482 Potsdam (Germany); Böhm, M. [innoFSPEC-InFaSe, University of Potsdam, Am Mühlenberg 3, 14476 Golm (Germany); Blow, K. [Aston Institute of Photonic Technologies, Aston Triangle, Birmingham B4 7ET (United Kingdom); Rieznik, A. A. [Instituto Tecnologico de Buenos Aires and CONICET, Buenos Aires (Argentina)

    2015-10-15

    We propose a fibre-based approach for generation of optical frequency combs (OFCs) with the aim of calibration of astronomical spectrographs in the low and medium-resolution range. This approach includes two steps: in the first step, an appropriate state of optical pulses is generated and subsequently moulded in the second step delivering the desired OFC. More precisely, the first step is realised by injection of two continuous-wave (CW) lasers into a conventional single-mode fibre, whereas the second step generates a broad OFC by using the optical solitons generated in step one as initial condition. We investigate the conversion of a bichromatic input wave produced by two initial CW lasers into a train of optical solitons, which happens in the fibre used as step one. Especially, we are interested in the soliton content of the pulses created in this fibre. For that, we study different initial conditions (a single cosine-hump, an Akhmediev breather, and a deeply modulated bichromatic wave) by means of soliton radiation beat analysis and compare the results to draw conclusion about the soliton content of the state generated in the first step. In case of a deeply modulated bichromatic wave, we observed the formation of a collective soliton crystal for low input powers and the appearance of separated solitons for high input powers. An intermediate state showing the features of both, the soliton crystal and the separated solitons, turned out to be most suitable for the generation of OFC for the purpose of calibration of astronomical spectrographs.

  19. Arterial blood pressure measurement and pulse wave analysis--their role in enhancing cardiovascular assessment.

    Science.gov (United States)

    Avolio, Alberto P; Butlin, Mark; Walsh, Andrew

    2010-01-01

    The most common method of clinical measurement of arterial blood pressure is by means of the cuff sphygmomanometer. This instrument has provided fundamental quantitative information on arterial pressure in individual subjects and in populations and facilitated estimation of cardiovascular risk related to levels of blood pressure obtained from the brachial cuff. Although the measurement is taken in a peripheral limb, the values are generally assumed to reflect the pressure throughout the arterial tree in large conduit arteries. Since the arterial pressure pulse becomes modified as it travels away from the heart towards the periphery, this is generally true for mean and diastolic pressure, but not for systolic pressure, and so pulse pressure. The relationship between central and peripheral pulse pressure depends on propagation characteristics of arteries. Hence, while the sphygmomanometer gives values of two single points on the pressure wave (systolic and diastolic pressure), there is additional information that can be obtained from the time-varying pulse waveform that enables an improved quantification of the systolic load on the heart and other central organs. This topical review will assess techniques of pressure measurement that relate to the use of the cuff sphygmomanometer and to the non-invasive registration and analysis of the peripheral and central arterial pressure waveform. Improved assessment of cardiovascular function in relation to treatment and management of high blood pressure will result from future developments in the indirect measurement of arterial blood pressure that involve the conventional cuff sphygmomanometer with the addition of information derived from the peripheral arterial pulse. PMID:19940350

  20. Arterial blood pressure measurement and pulse wave analysis—their role in enhancing cardiovascular assessment

    International Nuclear Information System (INIS)

    The most common method of clinical measurement of arterial blood pressure is by means of the cuff sphygmomanometer. This instrument has provided fundamental quantitative information on arterial pressure in individual subjects and in populations and facilitated estimation of cardiovascular risk related to levels of blood pressure obtained from the brachial cuff. Although the measurement is taken in a peripheral limb, the values are generally assumed to reflect the pressure throughout the arterial tree in large conduit arteries. Since the arterial pressure pulse becomes modified as it travels away from the heart towards the periphery, this is generally true for mean and diastolic pressure, but not for systolic pressure, and so pulse pressure. The relationship between central and peripheral pulse pressure depends on propagation characteristics of arteries. Hence, while the sphygmomanometer gives values of two single points on the pressure wave (systolic and diastolic pressure), there is additional information that can be obtained from the time-varying pulse waveform that enables an improved quantification of the systolic load on the heart and other central organs. This topical review will assess techniques of pressure measurement that relate to the use of the cuff sphygmomanometer and to the non-invasive registration and analysis of the peripheral and central arterial pressure waveform. Improved assessment of cardiovascular function in relation to treatment and management of high blood pressure will result from future developments in the indirect measurement of arterial blood pressure that involve the conventional cuff sphygmomanometer with the addition of information derived from the peripheral arterial pulse. (topical review)

  1. Research of the elastic waves generated by a pulse laser. Excitation mechanism of elastic waves and application to nondestructive testing; Pulse laser de reikishita danseiha ni kansuru kenkyu. Danseiha reiki no mechanism to hihakai kensa eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Cho, H.; Takemoto, M. [Aoyama Gakuin University, Tokyo (Japan). College of Science and Engineering

    1994-07-20

    A bulk wave is generated when a pulse laser is irradiated to the material, and the characteristics of a Young`s modulus and Poisson`s ratio can be nondestructively estimated from the bulk wave. The generation mechanism of laser ultrasonic waves must be first clarified for such application. In this paper, fundamental research was conducted to study the generation mechanism of the elastic waves excited by a Q-switched Nd-YAG laser, and the generation method and characteristics of Rayleigh waves. The following result was obtained. A bulk wave is generated by the disk-like adiabatic expansion near the surface if the laser power is small when a spot-shape pulse laser was irradiated. A bulk wave is generated by the thin disk-like adiabatic expansion beneath the surface due to the thermal diffusion in the depth direction of a base material when the laser power becomes large. Moreover, a bulk wave is generated by the impact force due to abrasion and plasma when the power becomes still larger. The information on the bulk wave characteristics and Rayleigh wave was also obtained. 25 refs., 15 figs., 1 tab.

  2. Human Heart Pulse Wave Responses Measured Simultaneously at Several Sensor Placements by Two MR-Compatible Fibre Optic Methods

    Directory of Open Access Journals (Sweden)

    Teemu Myllylä

    2012-01-01

    Full Text Available This paper presents experimental measurements conducted using two noninvasive fibre optic methods for detecting heart pulse waves in the human body. Both methods can be used in conjunction with magnetic resonance imaging (MRI. For comparison, the paper also performs an MRI-compatible electrocardiogram (ECG measurement. By the simultaneous use of different measurement methods, the propagation of pressure waves generated by each heart pulse can be sensed extensively in different areas of the human body and at different depths, for example, on the chest and forehead and at the fingertip. An accurate determination of a pulse wave allows calculating the pulse transit time (PTT of a particular heart pulse in different parts of the human body. This result can then be used to estimate the pulse wave velocity of blood flow in different places. Both measurement methods are realized using magnetic resonance-compatible fibres, which makes the methods applicable to the MRI environment. One of the developed sensors is an extraordinary accelerometer sensor, while the other one is a more common sensor based on photoplethysmography. All measurements, involving several test patients, were performed both inside and outside an MRI room. Measurements inside the MRI room were conducted using a 3-Tesla strength closed MRI scanner in the Department of Diagnostic Radiology at the Oulu University Hospital.

  3. Generation of spherical and cylindrical shock acoustic waves from optical breakdown in water, stimulated with femtosecond pulse

    CERN Document Server

    Potemkin, F V; Podshivalov, A A; Gordienko, V M

    2014-01-01

    Using shadow photography technique we have observed shock acoustic wave from optical breakdown, excited in water by tightly focused Cr:Forsterite femtosecond laser beam, and have found two different regimes of shock wave generation by varying only the energy of laser pulse. At low energies a single spherical shock wave is generated from laser beam waist, and its radius tends to saturation with energy increasing. At higher energies long laser filament in water is fired, that leads to the cylindrical shock wave generation, which longitude increases logarithmically with laser pulse energy. From shadow pictures we estimated maximal velocity in front or shock wave of 2300+/-150m/s and pressure of 1.0+/-0.1 GPa

  4. On the Design of Passive Resonant Circuits to Measure Local Pulse Wave Velocity in a Stent.

    Science.gov (United States)

    Schächtele, Jonathan

    2016-06-01

    In-stent restenosis is a frequent complication after stent implantation. This article investigates the design of a passive sensor system to be integrated into a stent for the detection of an in-stent restenosis by measuring the local pulse wave velocity (PWV). The proposed system uses two resonant circuits consisting of a capacitive pressure sensor and a coil as transponders. The pressure sensors are located at the proximal and distal end of the stent. An alternating external magnetic field with a constant frequency is applied such that the resonance frequencies of the transponders cross the excitation frequency when the pulse wave passes. The time delay between the resonances at the transponders can be captured to obtain the PWV. A model for the measurement system and a correlation between transponder design parameters and minimal resolvable time delay are derived. This correlation is based on the criterion that the 3 dB bandwidth of the transponder resonances may not overlap in the measurement time interval. This correlation can be used to design and analyze a transponder system for the proposed measurement system. In an experiment, in which the pressure sensors have been emulated by varactor diodes, it could be shown that the model is valid and that the criterion is suitable. Finally, the relevant design parameters of the transponders have been identified and their limitations investigated. PMID:26800547

  5. Smart photoplethysmographic sensor for pulse wave registration at different vascular depths.

    Science.gov (United States)

    Leier, Mairo; Pilt, Kristjan; Karai, Deniss; Jervan, Gert

    2015-01-01

    The aim of this paper is to propose a smart optical sensor for cardiovascular activity monitoring at different tissue layers. Photoplethysmography (PPG) is a noninvasive optical technique for monitoring mainly blood volume changes in the examined tissue. However, different important physiological parameters, such as oxygen saturation, heart and breathing rate, dynamics of skin micro-circulation, vasomotion activity etc., can be extracted from the registered PPG signal. The developed sensor consists of 32 light emitting sources with four different wavelengths, which are located to the four different distances from four photo detectors. Compared to the existing sensors, the system enables to select the optimal LED (light emitting diode) and photo detector couple in order to obtain the pulse wave signal from the interested blood vessels with the highest possible signal to noise ratio. In this study, the designed PPG sensor was tested for the pulse wave registration from radial artery. The highest efficiency and signal to noise ratio was achieved using infrared LED (940 nm) and photo-diode pair. PMID:26736641

  6. One-dimensional computational model of pulse wave propagation in the human bronchial tree.

    Science.gov (United States)

    Clavica, Francesco; Alastruey, Jordi; Borlotti, Alessandra; Sherwin, Spencer J; Khir, Ashraf W

    2010-01-01

    Airflow in the respiratory system has been predominantly studied in rigid ducts. Three-dimensional simulations are computationally expensive. One-dimensional (1-D) modelling offers a good compromise between accuracy and computational cost. In this work we described the propagation of air pulse in a model of human airways using the 1-D equations of flow in compliant vessels. Seven generations of bifurcations, starting from the trachea, were studied. Peripheral airways (from the 8(th) to 23(rd) generation) were modelled using lumped parameter models. Peripheral resistance values for normal and emphysematous lungs were taken from the literature. An acceleration pulse, very short in time, was enforced at the inlet of trachea. The results suggest that compression (positive pressure peaks) and expansion (negative pressure peaks) waves are generated according to the reflection coefficients of the corresponding reflection sites (bifurcations and terminal reflections). Different values for peripheral bronchial resistance generate three different terminal reflections, all negative with different wave amplitudes. The sensitivity of the code to different peripheral resistances suggests that the 1-D formulation is a promising tool for a better understanding of the impact of disease on the velocity and pressure waveforms in the first generations of airway vessels. PMID:21096163

  7. Phase-locking and Pulse Generation in Multi-Frequency Brillouin Oscillator via Four Wave Mixing

    Science.gov (United States)

    Büttner, Thomas F. S.; Kabakova, Irina V.; Hudson, Darren D.; Pant, Ravi; Poulton, Christopher G.; Judge, Alexander C.; Eggleton, Benjamin J.

    2014-05-01

    There is an increasing demand for pulsed all-fibre lasers with gigahertz repetition rates for applications in telecommunications and metrology. The repetition rate of conventional passively mode-locked fibre lasers is fundamentally linked to the laser cavity length and is therefore typically ~10-100 MHz, which is orders of magnitude lower than required. Cascading stimulated Brillouin scattering (SBS) in nonlinear resonators, however, enables the formation of Brillouin frequency combs (BFCs) with GHz line spacing, which is determined by the acoustic properties of the medium and is independent of the resonator length. Phase-locking of such combs therefore holds a promise to achieve gigahertz repetition rate lasers. The interplay of SBS and Kerr-nonlinear four-wave mixing (FWM) in nonlinear resonators has been previously investigated, yet the phase relationship of the waves has not been considered. Here, we present for the first time experimental and numerical results that demonstrate phase-locking of BFCs generated in a nonlinear waveguide cavity. Using real-time measurements we demonstrate stable 40 ps pulse trains with 8 GHz repetition rate based on a chalcogenide fibre cavity, without the aid of any additional phase-locking element. Detailed numerical modelling, which is in agreement with the experimental results, highlight the essential role of FWM in phase-locking of the BFC.

  8. Twenty-Four-Hour Ambulatory Pulse Wave Analysis in Hypertension Management: Current Evidence and Perspectives.

    Science.gov (United States)

    Omboni, Stefano; Posokhov, Igor N; Kotovskaya, Yulia V; Protogerou, Athanase D; Blacher, Jacques

    2016-10-01

    The predictive value of vascular biomarkers such as pulse wave velocity (PWV), central arterial pressure (CAP), and augmentation index (AIx), obtained through pulse wave analysis (PWA) in resting conditions, has been documented in a variety of patient groups and populations. This allowed to make appropriate recommendations in clinical practice guidelines of several scientific societies. Due to advances in technologies, largely operator-independent methods are currently available for estimating vascular biomarkers also in ambulatory conditions, over the 24 h. According to the acceptable accuracy and reproducibility of 24-h ambulatory PWA, it appears to be a promising tool for evaluating vascular biomarkers in daily life conditions. This approach may provide an opportunity to further improve the early cardiovascular screening in subjects at risk. However, concerning the clinical use of PWA over the 24 h in ambulatory conditions at the moment, there is no sufficient evidence to support its routine clinical use. In particular, long-term outcome studies are needed to show the predictive value of 24-h PWV, CAP, and AIx values, provided by these devices, over and beyond peripheral blood pressure, and to answer the many technical and clinical questions still open. To this regard, the VASOTENS Registry, an international observational prospective study recently started, will help providing answers on a large sample of hypertensive patients recruited worldwide. PMID:27659178

  9. Targeted gene transfer into rat facial muscles by nanosecond pulsed laser-induced stress waves

    Science.gov (United States)

    Kurita, Akihiro; Matsunobu, Takeshi; Satoh, Yasushi; Ando, Takahiro; Sato, Shunichi; Obara, Minoru; Shiotani, Akihiro

    2011-09-01

    We investigate the feasibility of using nanosecond pulsed laser-induced stress waves (LISWs) for gene transfer into rat facial muscles. LISWs are generated by irradiating a black natural rubber disk placed on the target tissue with nanosecond pulsed laser light from the second harmonics (532 nm) of a Q-switched Nd:YAG laser, which is widely used in head and neck surgery and proven to be safe. After injection of plasmid deoxyribose nucleic acid (DNA) coding for Lac Z into rat facial muscles, pulsed laser is used to irradiate the laser target on the skin surface without incision or exposure of muscles. Lac Z expression is detected by X-gal staining of excised rat facial skin and muscles. Strong Lac Z expression is observed seven days after gene transfer, and sustained for up to 14 days. Gene transfer is achieved in facial muscles several millimeters deep from the surface. Gene expression is localized to the tissue exposed to LISWs. No tissue damage from LISWs is observed. LISW is a promising nonviral target gene transfer method because of its high spatial controllability, easy applicability, and minimal invasiveness. Gene transfer using LISW to produce therapeutic proteins such as growth factors could be used to treat nerve injury and paralysis.

  10. Pulse wave detection method based on the bio-impedance of the wrist

    Science.gov (United States)

    He, Jianman; Wang, Mengjun; Li, Xiaoxia; Li, Gang; Lin, Ling

    2016-05-01

    The real-time monitoring of pulse rate can evaluate the heart health to some extent, and the measurement of bio-impedance has the potential in wearable health monitoring system. In this paper, an effective method, which contains self-balancing bridge, flexible electrode, and high-speed digital lock-in algorithm (DLIA) with over-sampling, was designed to detect the impedance pulse wave at the wrist. By applying the self-balancing bridge, the basic impedance can be compensated as much as possible, and the low amplitude of impedance variation related to heart pulse can be obtained more easily. And the flexible conductive rubber electrode used in our experiment is human-friendly. Besides, the over-sampling method and high-speed DLIA are used to enhance the effective resolution of the existing data sampled by analog to digital converter. With the high-speed data process and simple circuit above, this proposed method has the potential in wrist-band wearable systems and it can satisfy quests of small volume and low power consumption.

  11. Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor

    CERN Document Server

    Chen, Yi-Hsin; Löw, Robert; Pfau, Tilman

    2015-01-01

    We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns time scales. Combined with a third cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report [1] using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity...

  12. Enhancement of Lamb Wave Imaging Resolution by Step Pulse Excitation and Prewarping

    Directory of Open Access Journals (Sweden)

    Shangchen Fu

    2015-01-01

    Full Text Available For the purpose of improving the damage localization accuracy, a prewarping technology is combined with step pulse excitation and this method is used in Lamb wave imaging of plate structures with adjacent damages. Based on the step pulse excitation, various narrowband or burst response can be derived by signal processing technology and this method provides flexibility for further prewarping approach. A narrowband signal warped with a preselected distance is then designed, and the dispersion in the response of this prewarping signal will be greatly reduced. However, in order to calculate the distance for prewarping, the first arrival needs to be estimated from the burst response. From the step-pulse response, narrowband responses at different central frequencies can be obtained, and by averaging peak-value time of their first arrivals, a more accurate estimation can be calculated. By using the prewarping method to the damage scattering signals before imaging, the imaging resolution of the delay-and-sum method can be highly enhanced. The experiment carried out in an aluminum plate with adjacent damages proves the efficiency of this method.

  13. Photoplethysmography beyond perfusion and oxygenation monitoring: Pulse wave analysis for hepatic graft monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Akl, Tony [Texas A& M University; Wilson, Mark A. [University of Pittsburgh School of Medicine, Pittsburgh PA; Ericson, Milton Nance [ORNL; Cote, Gerard L. [Texas A& M University

    2014-01-01

    Photoplethysmography is a widely used technique in monitoring perfusion and blood oxygen saturation by using the amplitude of the pulsatile signal on one or multiple wavelengths. However, the pulsatile signal carries in its waveform a substantial amount of information about the mechanical properties of the tissue and vasculature under investigation that is still yet to be utilized to its full potential. In this work, we present the feasibility of pulse wave analysis for the application of monitoring hepatic implants and diagnosing graft complications. In particular, we show the possibility of computing the slope of the pulse during the diastole phase to assess the location of vascular complications when they take place. This hypothesis was tested in a series of in vitro experiments using a PDMS based phantom mimicking the optical and mechanical properties of the portal vein. The emptying time of the vessel increased from 305 ms to 515 ms when an occlusion was induced downstream from the phantom. However, in the case of upstream occlusions, the emptying time remained constant. In both cases, a decrease in the amplitude of the pulse was recorded indicating the drop in flow levels. In addition, we show that quantifying the emptying time of the vasculature under investigation can be used to assess its compliance. The emptying time decreased from 305 ms for phantoms with compliance of 15 KPa to 195 ms for phantoms with compliance of 100 KPa. These compliance levels mimic those seen for normal and fibrotic hepatic tissue respectively.

  14. Effects of bee venom acupuncture on heart rate variability, pulse wave, and cerebral blood flow for types of Sasang Constitution

    Directory of Open Access Journals (Sweden)

    Lee Sang-min

    2009-03-01

    Full Text Available 1. Objectives: To evaluate effects of bee venom acupuncture on cardiovascular system and differences according to each constitution. 2. Methods: Heart rate variability, pulse wave and the velocity of cerebral blood flow were measured before bee venom acupuncture(BVA, right after and after 30 minuets, had been applied to 20 subjects. 3. Results: 1. BVA did not have effects on measurement variables of heart rate variability. 2. BVA had effects on pulse wave, showing total time, radial augmentation index up and height of percussion wave, time to percussion wave, sum of pulse pressure down. 3. BVA did not have effects on the cerebral blood flow velocity when considering not Sasang Constitution 4. Considering Sasang Constitution, BVA demonstrates different responses in time to preincisura wave, mean blood flow velocity, peak systolic velocity and end diastolic velocity. 4.Conclusion: From those results, the following conclusions are obtained. Cause BVA alters pulse wave and makes differences in the cerebral blood flow velocity according to Sasang Constitution. Various methods of BVA treatment are needed considering Sasang Constitution.

  15. Arterial pulse wave velocity, inflammatory markers, pathological GH and IGF states, cardiovascular and cerebrovascular disease

    Directory of Open Access Journals (Sweden)

    Michael R Graham

    2008-12-01

    Full Text Available Michael R Graham1, Peter Evans2, Bruce Davies1, Julien S Baker11Health and Exercise Science Research Unit, Faculty of Health Sport and Science, University of Glamorgan, Pontypridd, Wales, United Kingdom; 2Royal Gwent Hospital, Newport, Gwent, United KingdomAbstract: Blood pressure (BP measurements provide information regarding risk factors associated with cardiovascular disease, but only in a specific artery. Arterial stiffness (AS can be determined by measurement of arterial pulse wave velocity (APWV. Separate from any role as a surrogate marker, AS is an important determinant of pulse pressure, left ventricular function and coronary artery perfusion pressure. Proximal elastic arteries and peripheral muscular arteries respond differently to aging and to medication. Endogenous human growth hormone (hGH, secreted by the anterior pituitary, peaks during early adulthood, declining at 14% per decade. Levels of insulin-like growth factor-I (IGF-I are at their peak during late adolescence and decline throughout adulthood, mirror imaging GH. Arterial endothelial dysfunction, an accepted cause of increased APWV in GH deficiency (GHD is reversed by recombinant human (rh GH therapy, favorably influencing the risk for atherogenesis. APWV is a noninvasive method for measuring atherosclerotic and hypertensive vascular changes increases with age and atherosclerosis leading to increased systolic blood pressure and increased left ventricular hypertrophy. Aerobic exercise training increases arterial compliance and reduces systolic blood pressure. Whole body arterial compliance is lowered in strength-trained individuals. Homocysteine and C-reactive protein are two infl ammatory markers directly linked with arterial endothelial dysfunction. Reviews of GH in the somatopause have not been favorable and side effects of treatment have marred its use except in classical GHD. Is it possible that we should be assessing the combined effects of therapy with rhGH and rh

  16. Aortic distensibility measured by pulse-wave velocity is not modified in patients with Chagas' disease

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    Arteaga Edmundo

    2006-06-01

    Full Text Available Abstract Background Experimental studies demonstrate that infection with trypanosoma cruzi causes vasculitis. The inflammatory lesion process could hypothetically lead to decreased distensibility of large and small arteries in advanced Chagas' disease. We tested this hypothesis. Methods and results We evaluated carotid-femoral pulse-wave velocity (PWV in 53 Chagas' disease patients compared with 31 healthy volunteers (control group. The 53 patients were classified into 3 groups: 1 16 with indeterminate form of Chagas' disease; 2 18 with Chagas' disease, electrocardiographic abnormalities, and normal systolic function; 3 19 with Chagas' disease, systolic dysfunction, and mild-to-moderate congestive heart failure. No difference was noted between the 4 groups regarding carotid-femoral PWV (8.4 ± 1.1 vs 8.2 ± 1.5 vs 8.2 ± 1.4 vs 8.7 ± 1.6 m/s, P = 0.6 or pulse pressure (39.5 ± 7.6 vs 39.3 ± 8.1 vs 39.5 ± 7.4 vs 39.7 ± 6.9 mm Hg, P = 0.9. A positive, significant, similar correlation occurred between PWV and age in patients with Chagas' disease (r = 0.42, P = 0.002, in controls (r = 0.48, P = 0.006, and also between PWV and systolic blood pressure in both groups (patients with Chagas' disease, r = 0.38, P = 0.005; healthy subjects, r = 0.36, P = 0.043. Conclusion Carotid femoral pulse-wave velocity is not modified in patients with Chagas' disease, suggesting that elastic properties of large arteries are not affected in this disorder.

  17. Characteristics of ZnO nanostructures synthesized by sonochemical reaction: Effects of continuous and pulse waves

    Energy Technology Data Exchange (ETDEWEB)

    Widiyastuti, W., E-mail: widi@chem-eng.its.ac.id; Machmudah, Siti; Kusdianto,; Nurtono, Tantular; Winardi, Sugeng [Department of Chemical Engineering, Institut Teknologi Sepuluh Nopember, Kampus ITS Sukolilo Surabaya 60111 (Indonesia)

    2015-12-29

    Nanostructured ZnO was synthesized by a sonochemical reaction. Ultrasonic irradiation were set up in continuous, pulse in 3 seconds on and a second off (on:off=3:1), and pulse in 2 seconds on and a second off (on:off=2:1) wave modes for 1.5 hours. The characteristics of particles generated by these modes such as morphology, crystallinity, FTIR, photoluminescence, and photocatalytic activity to degrade methylene blue were compared. Zinc nitrate and ammonia water-based solutions were selected as chemicals without the addition of other surfactants. The morphology of the generated ZnO particles could be tuned from flower-like, needle- or hairy-like, and spherical structures by changing the mode of ultrasonic irradiation from continuous, on:off=3:1, and on:off=2:1 modes, respectively. The generated particles indicated that a wurtzite structure of ZnO in a hexagonal phase was formed. The crystalline sizes of particles generated in continuous, on:off=3:1, and on:off=2:1 modes were 28, 27, 24 nm. A similar position of reduction peak of FTIR in all samples indicated that no differences in particles chemical bonding characteristics. Photoluminescence intensity was also decreased with changes the wave mode from continuous to pulse. Photocatalytic activity was also evaluated resulting in particles synthesized by continuous mode had the highest methylene blue degradation degree following by on:off=3:1, and on:off=2:1 modes.

  18. Uncertainty quantification of inflow boundary condition and proximal arterial stiffness coupled effect on pulse wave propagation in a vascular network

    CERN Document Server

    Brault, A; Lucor, D

    2016-01-01

    SUMMARY This work aims at quantifying the effect of inherent uncertainties from cardiac output on the sensitivity of a human compliant arterial network response based on stochastic simulations of a reduced-order pulse wave propagation model. A simple pulsatile output form is utilized to reproduce the most relevant cardiac features with a minimum number of parameters associated with left ventricle dynamics. Another source of critical uncertainty is the spatial heterogeneity of the aortic compliance which plays a key role in the propagation and damping of pulse waves generated at each cardiac cycle. A continuous representation of the aortic stiffness in the form of a generic random field of prescribed spatial correlation is then considered. Resorting to a stochastic sparse pseudospectral method, we investigate the spatial sensitivity of the pulse pressure and waves reflection magnitude with respect to the different model uncertainties. Results indicate that uncertainties related to the shape and magnitude of th...

  19. Generation of thermo-acoustic waves from pulsed solar/IR radiation

    Science.gov (United States)

    Rahman, Aowabin

    Acoustic waves could potentially be used in a wide range of engineering applications; however, the high energy consumption in generating acoustic waves from electrical energy and the cost associated with the process limit the use of acoustic waves in industrial processes. Acoustic waves converted from solar radiation provide a feasible way of obtaining acoustic energy, without relying on conventional nonrenewable energy sources. One of the goals of this thesis project was to experimentally study the conversion of thermal to acoustic energy using pulsed radiation. The experiments were categorized into "indoor" and "outdoor" experiments, each with a separate experimental setup. The indoor experiments used an IR heater to power the thermo-acoustic lasers and were primarily aimed at studying the effect of various experimental parameters on the amplitude of sound waves in the low frequency range (below 130 Hz). The IR radiation was modulated externally using a chopper wheel and then impinged on a porous solid, which was housed inside a thermo-acoustic (TA) converter. A microphone located at a certain distance from the porous solid inside the TA converter detected the acoustic signals. The "outdoor" experiments, which were targeted at TA conversion at comparatively higher frequencies (in 200 Hz-3 kHz range) used solar energy to power the thermo-acoustic laser. The amplitudes (in RMS) of thermo-acoustic signals obtained in experiments using IR heater as radiation source were in the 80-100 dB range. The frequency of acoustic waves corresponded to the frequency of interceptions of the radiation beam by the chopper. The amplitudes of acoustic waves were influenced by several factors, including the chopping frequency, magnitude of radiation flux, type of porous material, length of porous material, external heating of the TA converter housing, location of microphone within the air column, and design of the TA converter. The time-dependent profile of the thermo-acoustic signals

  20. Ionospheric cusp flows pulsed by solar wind Alfvén waves

    Directory of Open Access Journals (Sweden)

    P. Prikryl

    Full Text Available Pulsed ionospheric flows (PIFs in the cusp foot-print have been observed by the SuperDARN radars with periods between a few minutes and several tens of minutes. PIFs are believed to be a consequence of the interplanetary magnetic field (IMF reconnection with the magnetospheric magnetic field on the dayside magnetopause, ionospheric signatures of flux transfer events (FTEs. The quasiperiodic PIFs are correlated with Alfvénic fluctuations observed in the upstream solar wind. It is concluded that on these occasions, the FTEs were driven by Alfvén waves coupling to the day-side magnetosphere. Case studies are presented in which the dawn-dusk component of the Alfvén wave electric field modulates the reconnection rate as evidenced by the radar observations of the ionospheric cusp flows. The arrival of the IMF southward turning at the magnetopause is determined from multipoint solar wind magnetic field and/or plasma measurements, assuming plane phase fronts in solar wind. The cross-correlation lag between the solar wind data and ground magnetograms that were obtained near the cusp footprint exceeded the estimated spacecraft-to-magnetopause propagation time by up to several minutes. The difference can account for and/or exceeds the Alfvén propagation time between the magnetopause and ionosphere. For the case of short period ( < 13 min PIFs, the onset times of the flow transients appear to be further delayed by at most a few more minutes after the IMF southward turning arrived at the magnetopause. For the case of long period (30 – 40 min PIFs, the observed additional delays were 10–20 min. We interpret the excess delay in terms of an intrinsic time scale for reconnection (Russell et al., 1997 which can be explained by the surface-wave induced magnetic reconnection mechanism (Uberoi et al., 1999. Here, surface waves with wavelengths larger than the thickness of the neutral layer induce a tearing-mode instability whose rise time explains the

  1. Effect of pulse-wave factors in Middle Aged Women by Mountain Cultivated Ginseng Pharmacopuncture Original Articles

    Directory of Open Access Journals (Sweden)

    Park Sang Wook

    2011-03-01

    Full Text Available Objectives: The aim of this experiment is to know about Effect of pulse-wave factors in Middle Aged Women by Mountain Cultivated Ginseng Pharmacopuncture. Methods: First 20 Middle Aged women are diagnosed by pulse diagnosis, and then Mountain Cultivated Ginseng Pharmacopuncture(1 injection 20cc were injected. 30 minutes later, pulse diagnosis again performed. As a result, method of one-group pretest-posttes design were used for evaluation. Results: T(Total pulse cycle time statistically significant increased on both left and right chon, kwan,cheok. T4 time statistically significant increased on both left and right chon, kwan, cheok. T4-T1/T indexs except left cheokmaek, Right cheokmaek observation area decreased significantly in four sites.Wm(indicating high pressure retention time indexs increased significantly in the five sites were observed except right chon maek. Conclusions: Effect of pulse-wave factors in Middle Aged Women by Mountain Cultivated Ginseng Pharmacopuncture increased T, T4, Wm and decreased T4-T1/T indexs. The results of this experiment,Mountain Cultivated Ginseng Pharmacopuncture induced to increase the Pulse-wave's stability and strength.

  2. Experimental study regarding the effects of pulsed short waves on nervous tissue

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    DOGARU Gabriela

    2014-05-01

    Full Text Available Pulsed short waves are part of high frequency therapy and have through their biological effects, the good therapeutic results and the lack of side effects many indications in various disorders: rheumatologic, traumatologic, burns, neurological (nerve tissue regeneration, ischemic vascular accidents, vascular disorders. The experimental study consisted of the exposure of laboratory animals to the action of pulsed short waves in different doses and the monitoring of changes in the brain cellular and subcellular structure. The study included 35 Wistar rats, assigned to four groups, three groups of 10 animals and the control group of five non-irradiated animals. Group I was exposed to a dose of 1/80 cycles/sec, group II to 4/400 cycles/sec, and group III to 6/600 cycles/sec, for 10 minutes/day, for 15 days. After the rats were sacrificed, nervous tissue fragments were collected. These were adequately processed for their examination by optical and electron microscopy. At structural level, in the control group and the groups exposed to the dose of 1/80 cycles/sec, the neurons were normally structured. In group II, a slight increase of brain metabolic activity was seen, in group III there was a significant increase of brain metabolism, with better myelinated white matter axons, which suggests a better protection for the rapid conduction of nerve impulses to effectors. In group II, electron microscopy revealed similar aspects to those of the control group. A high ribosome density was found in the neuroplasm, which means an intense protein synthesis process. In group III, there was an intense protein synthesis activity, and a strong axon myelination in the white matter, resulting in a better protection for the transmission of nerve impulses. Conclusions: pulsed short waves caused brain changes depending on the dose. The analysis of electron microscopic images showed that irradiation at a dose of 6/600 cycles/sec induced an intense protein synthesis

  3. Multi-wave ultrasonic Doppler method for measuring high flow-rates using staggered pulse intervals

    Science.gov (United States)

    Muramatsu, Ei; Murakawa, Hideki; Sugimoto, Katsumi; Asano, Hitoshi; Takenaka, Nobuyuki; Furuichi, Noriyuki

    2016-02-01

    The ultrasonic pulsed Doppler method (UDM) can obtain a velocity profile along the path of an ultrasonic beam. However, the UDM measurement volume is relatively large and it is known that the measurement volume affects the measurement accuracy. In this study, the effect of the measurement volume on velocity and flow rate measurements is analytically and experimentally evaluated. The velocities measured using UDM are considered to be ensemble-averaged values over the measurement volume in order to analyze the velocity error due to the measurement volume, while the flow rates are calculated from the integration of the velocity profile across the pipe. The analytical results show that the channel width, i.e. the spatial resolution along the ultrasonic beam axis, rather than the ultrasonic beam diameter, strongly influences the flow rate measurement. To improve the accuracy of the flow rate, a novel method using a multi-wave ultrasonic transducer consisting of two piezo-electric elements with different basic frequencies is proposed to minimize the size of the measurement volume in the near-wall region of a pipe flow. The velocity profiles in the near-wall region are measured using an 8 MHz sensor with a small diameter, while those far from the transducer are measured using a hollow 2 MHz sensor in the multi-wave transducer. The applicability of the multi-wave transducer was experimentally investigated using the water flow-rate calibration facility at the National Institute of Advanced Industrial Science and Technology (AIST). As a result, the errors in the flow rate were found to be below  -1%, while the multi-wave method is shown to be particularly effective for measuring higher flow rates in a large-diameter pipe.

  4. Multi-wave ultrasonic Doppler method for measuring high flow-rates using staggered pulse intervals

    International Nuclear Information System (INIS)

    The ultrasonic pulsed Doppler method (UDM) can obtain a velocity profile along the path of an ultrasonic beam. However, the UDM measurement volume is relatively large and it is known that the measurement volume affects the measurement accuracy. In this study, the effect of the measurement volume on velocity and flow rate measurements is analytically and experimentally evaluated. The velocities measured using UDM are considered to be ensemble-averaged values over the measurement volume in order to analyze the velocity error due to the measurement volume, while the flow rates are calculated from the integration of the velocity profile across the pipe. The analytical results show that the channel width, i.e. the spatial resolution along the ultrasonic beam axis, rather than the ultrasonic beam diameter, strongly influences the flow rate measurement. To improve the accuracy of the flow rate, a novel method using a multi-wave ultrasonic transducer consisting of two piezo-electric elements with different basic frequencies is proposed to minimize the size of the measurement volume in the near-wall region of a pipe flow. The velocity profiles in the near-wall region are measured using an 8 MHz sensor with a small diameter, while those far from the transducer are measured using a hollow 2 MHz sensor in the multi-wave transducer. The applicability of the multi-wave transducer was experimentally investigated using the water flow-rate calibration facility at the National Institute of Advanced Industrial Science and Technology (AIST). As a result, the errors in the flow rate were found to be below  −1%, while the multi-wave method is shown to be particularly effective for measuring higher flow rates in a large-diameter pipe. (paper)

  5. Three and four wave parametric interactions for ultrashort pulse generation in the ultraviolet, near and mid-infrared spectral range

    OpenAIRE

    Darginavičius, Julius

    2013-01-01

    In this thesis we investigated and developed three- and four-wave interaction-based frequency conversion methods for ultrashort pulse generation in the ultraviolet (UV), near and mid-infrared (IR) spectral ranges. In particular, efficient generation of Nd:glass laser harmonics was demonstrated experimentally, through noncollinear four-wave difference-frequency mixing in isotropic media. Also, broadband optical parametric amplification in the UV was investigated theoretically and achieved expe...

  6. Temporal isolation of surface-acoustic-wave-driven luminescence from a lateral p n junction using pulsed techniques

    Science.gov (United States)

    Gell, J. R.; Ward, M. B.; Atkinson, P.; Bremner, S. P.; Anderson, D.; Norman, C. E.; Kataoka, M.; Barnes, C. H. W.; Jones, G. A. C.; Shields, A. J.; Ritchie, D. A.

    2008-04-01

    The authors report surface-acoustic-wave-driven luminescence from a lateral p-n junction formed by molecular-beam epitaxy regrowth of a modulation doped GaAs/AlGaAs quantum well on a patterned GaAs substrate. Pulsed techniques are used to isolate the surface-acoustic-wave-driven emission from any emission due to pick-up of the free-space electromagnetic wave. The luminescence provides a fast probe of the signals arriving at the p-n junction allowing the response of the junction to the surface-acoustic-wave to be studied in the time domain. Oscillations in the surface-acoustic-wave-driven component of the light intensity are resolved at the resonant frequency of the transducer, suggesting that the surface-acoustic-wave is transporting electrons across the junction in packets.

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

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; LI Jiuqing; WU Yinshun; ZHANG Pei; HE Jianping

    2004-01-01

    Cerium contained conversion films were deposited on LC4 aluminum alloy using square wave pulse (SWP) in a CeC13 solution with KMnO4 as the oxidant. Energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) were adopted to study the composition and the morphology of the film. It is found that the film is composed of Al, Zn, Cu,and small amount of cerium. The polarization curves of the specimens treated with SWP technique measured in 3.5% (mass fraction) NaCl solution reveal that the film thus formed inhibits both the anodic and cathodic process of the corrosion of the specimen. The immersion tests of treated specimens in 3.5% NaCl solution indicate that the corrosion resistance of the SWP treated specimen is better than that of the untreated and is equivalent to or even better than that of the traditionally electrochemically treated specimens.

  8. Robust pulse wave velocity estimation by application of system identification to proximal and distal arterial waveforms.

    Science.gov (United States)

    Xu, Da; Ryan, Kathy L; Rickards, Caroline A; Zhang, Guanqun; Convertino, Victor A; Mukkamala, Ramakrishna

    2010-01-01

    Pulse wave velocity (PWV) is a marker of arterial stiffness and may permit continuous, non-invasive, and cuff-less monitoring of blood pressure. Here, robust PWV estimation was sought by application of system identification to proximal and distal arterial waveforms. In this approach, the system that optimally couples the proximal waveform to the distal waveform is identified, and the time delay of this system is then used to calculate PWV. To demonstrate proof-of-concept, a standard identification technique was applied to non-invasive impedance cardiography and peripheral arterial blood pressure waveforms from six humans subjected to progressive reductions in central blood volume induced by lower body negative pressure. This technique estimated diastolic pressure with an overall root-mean-squared-error of 5.2 mmHg. For comparison, the conventional detection method for estimating PWV yielded a corresponding error of 8.3 mmHg. PMID:21097042

  9. Electronic excitation by short x-ray pulses: from quantum beats to wave packet revivals

    Science.gov (United States)

    Rivière, P.; Iqbal, S.; Rost, J. M.

    2014-06-01

    We propose a simple way to determine the periodicities of wave packets (WPs) in quantum systems directly from the energy differences of the states involved. The resulting classical periods and revival times are more accurate than those obtained with the traditional expansion of the energies about the central quantum number \\overline{n}, especially when \\overline{n} is low. The latter type of WP motion occurs upon excitation of highly charged ions with short XUV or x-ray pulses. Moreover, we formulate the WP dynamics in such a form that it directly reveals the origin of phase shifts in the maxima of the autocorrelation function, a phenomenon most prominent in the low \\overline{n} WP dynamics.

  10. Central blood pressure assessment using 24-hour brachial pulse wave analysis

    Directory of Open Access Journals (Sweden)

    Muiesan ML

    2014-10-01

    Full Text Available Maria Lorenza Muiesan, Massimo Salvetti, Fabio Bertacchini, Claudia Agabiti-Rosei, Giulia Maruelli, Efrem Colonetti, Anna Paini Clinica Medica, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy Abstract: This review describes the use of central blood pressure (BP measurements during ambulatory monitoring, using noninvasive devices. The principles of measuring central BP by applanation tonometry and by oscillometry are reported, and information on device validation studies is described. The pathophysiological basis for the differences between brachial and aortic pressure is discussed. The currently available methods for central aortic pressure measurement are relatively accurate, and their use has important clinical implications, such as improving diagnostic and prognostic stratification of hypertension and providing a more accurate assessment of the effect of treatment on BP. Keywords: aortic blood pressure measurements, ambulatory monitoring, pulse wave analysis

  11. Evaluation of agreement between temporal series obtained from electrocardiogram and pulse wave.

    Science.gov (United States)

    Leikan, GM; Rossi, E.; Sanz, MCuadra; Delisle Rodríguez, D.; Mántaras, MC; Nicolet, J.; Zapata, D.; Lapyckyj, I.; Siri, L. Nicola; Perrone, MS

    2016-04-01

    Heart rate variability allows to study the cardiovascular autonomic nervous system modulation. Usually, this signal is obtained from the electrocardiogram (ECG). A simpler method for recording the pulse wave (PW) is by means of finger photoplethysmography (PPG), which also provides information about the duration of the cardiac cycle. In this study, the correlation and agreement between the time series of the intervals between heartbeats obtained from the ECG with those obtained from the PPG, were studied. Signals analyzed were obtained from young, healthy and resting subjects. For statistical analysis, the Pearson correlation coefficient and the Bland and Altman limits of agreement were used. Results show that the time series constructed from the PW would not replace the ones obtained from ECG.

  12. High Definition Oscillometry: Non-invasive Blood Pressure Measurement and Pulse Wave Analysis.

    Science.gov (United States)

    Egner, Beate

    2015-01-01

    Non-invasive monitoring of blood pressure has become increasingly important in research. High-Definition Oscillometry (HDO) delivers not only accurate, reproducible and thus reliable blood pressure but also visualises the pulse waves on screen. This allows for on-screen feedback in real time on data validity but even more on additional parameters like systemic vascular resistance (SVR), stroke volume (SV), stroke volume variances (SVV), rhythm and dysrhythmia. Since complex information on drug effects are delivered within a short period of time, almost stress-free and visible in real time, it makes HDO a valuable technology in safety pharmacology and toxicology within a variety of fields like but not limited to cardiovascular, renal or metabolic research. PMID:26091643

  13. Ethnic Differences in and Childhood Influences on Early Adult Pulse Wave Velocity

    Science.gov (United States)

    Silva, Maria J.; Molaodi, Oarabile R.; Enayat, Zinat E.; Cassidy, Aidan; Karamanos, Alexis; Read, Ursula M.; Faconti, Luca; Dall, Philippa; Stansfield, Ben; Harding, Seeromanie

    2016-01-01

    Early determinants of aortic stiffness as pulse wave velocity are poorly understood. We tested how factors measured twice previously in childhood in a multiethnic cohort study, particularly body mass, blood pressure, and objectively assessed physical activity affected aortic stiffness in young adults. Of 6643 London children, aged 11 to 13 years, from 51 schools in samples stratified by 6 ethnic groups with different cardiovascular risk, 4785 (72%) were seen again at aged 14 to 16 years. In 2013, 666 (97% of invited) took part in a young adult (21–23 years) pilot follow-up. With psychosocial and anthropometric measures, aortic stiffness and blood pressure were recorded via an upper arm calibrated Arteriograph device. In a subsample (n=334), physical activity was measured >5 days via the ActivPal. Unadjusted pulse wave velocities in black Caribbean and white UK young men were similar (mean±SD 7.9±0.3 versus 7.6±0.4 m/s) and lower in other groups at similar systolic pressures (120 mm Hg) and body mass (24.6 kg/m2). In fully adjusted regression models, independent of pressure effects, black Caribbean (higher body mass/waists), black African, and Indian young women had lower stiffness (by 0.5–0.8; 95% confidence interval, 0.1–1.1 m/s) than did white British women (6.9±0.2 m/s). Values were separately increased by age, pressure, powerful impacts from waist/height, time spent sedentary, and a reported racism effect (+0.3 m/s). Time walking at >100 steps/min was associated with reduced stiffness (Pracism) independently increase arterial stiffness, effects likely to increase with age. PMID:27141061

  14. Photon statistics of pulse-pumped four-wave mixing in fiber with weak signal injection

    Science.gov (United States)

    Nan-Nan, Liu; Yu-Hong, Liu; Jia-Min, Li; Xiao-Ying, Li

    2016-07-01

    We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental results show that the intensity correlation function of individual signal (idler) field decreases with the intensity of signal injection. After applying narrow band filter in signal (idler) band, the value of decreases from 1.9 ± 0.02 (1.9 ± 0.02) to 1.03 ± 0.02 (1.05 ± 0.02) when the intensity of signal injection varies from 0 to 120 photons/pulse. The results indicate that the photon statistics changes from Bose–Einstein distribution to Poisson distribution. We calculate the intensity correlation functions by using the multi-mode theory of four-wave mixing in fibers. The theoretical curves well fit the experimental results. Our investigation will be useful for mitigating the crosstalk between quantum and classical channels in a dense wavelength division multiplexing network. Project supported by the National Natural Science Foundation of China (Grant No. 11527808), the State Key Development Program for Basic Research of China (Grant No. 2014CB340103), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120032110055), the Natural Science Foundation of Tianjin, China (Grant No. 14JCQNJC02300), the Program for Changjiang Scholars and Innovative Research Team in University, China, and the Program of Introducing Talents of Discipline to Universities, China (Grant No. B07014).

  15. Frequency doubled high-power disk lasers in pulsed and continuous-wave operation

    Science.gov (United States)

    Weiler, Sascha; Hangst, Alexander; Stolzenburg, Christian; Zawischa, Ivo; Sutter, Dirk; Killi, Alexander; Kalfhues, Steffen; Kriegshaeuser, Uwe; Holzer, Marco; Havrilla, David

    2012-03-01

    The disk laser with multi-kW output power in infrared cw operation is widely used in today's manufacturing, primarily in the automotive industry. The disk technology combines high power (average and/or peak power), excellent beam quality, high efficiency and high reliability with low investment and operating costs. Additionally, the disk laser is ideally suited for frequency conversion due to its polarized output with negligible depolarization losses. Laser light in the green spectral range (~515 nm) can be created with a nonlinear crystal. Pulsed disk lasers with green output of well above 50 W (extracavity doubling) in the ps regime and several hundreds of Watts in the ns regime with intracavity doubling are already commercially available whereas intracavity doubled disk lasers in continuous wave operation with greater than 250 W output are in test phase. In both operating modes (pulsed and cw) the frequency doubled disk laser offers advantages in existing and new applications. Copper welding for example is said to show much higher process reliability with green laser light due to its higher absorption in comparison to the infrared. This improvement has the potential to be very beneficial for the automotive industry's move to electrical vehicles which requires reliable high-volume welding of copper as a major task for electro motors, batteries, etc.

  16. Serum Osteopontin Level Correlates with Carotid-Femoral Pulse Wave Velocity in Geriatric Persons

    Directory of Open Access Journals (Sweden)

    Chung-Jen Lee

    2014-01-01

    Full Text Available Osteopontin (OPN is involved in the regulation of vascular calcification processes. The aim of this study was to evaluate the relationship between fasting serum OPN concentration and carotid-femoral pulse wave velocity (cfPWV in geriatric persons. Fasting blood samples were obtained from 93 geriatric persons. cfPWV were performed by SphygmoCor system. Serum OPN levels were measured using a commercially available enzyme-linked immunosorbent assay. Geriatric adults who had diabetes (P=0.007 or dyslipidemia (P=0.029 had higher cfPWV levels than those without diabetes or dyslipidemia. The univariable linear regression analysis showed that age (P=0.002, waist circumference (P=0.048, body mass index (P=0.004, systolic blood pressure (P=0.001, diastolic blood pressure (P=0.036, pulse pressure (P=0.017, creatinine (P=0.002, and log-OPN level (P=0.001 were positively correlated with cfPWV levels, while the high-density lipoprotein cholesterol (HDL-cholesterol level (P=0.007 and glomerular filtration rate (P=0.001 were negatively correlated with cfPWV levels among the geriatric adults. Multivariable forward stepwise linear regression analysis of the significant variables also showed that log-OPN (β=0.233, R2=0.123, regression coefficient: 1.868, P=0.011 was still an independent predictor of cfPWV levels in geriatric persons.

  17. Low temperature phase barium borate: A new optical limiter in continuous wave and nano pulsed regime

    Science.gov (United States)

    Babeela, C.; Girisun, T. C. Sabari

    2015-11-01

    Low temperature phase barium borate was synthesized by hydrothermal method. XRD analysis confirms the formation of γ-BBO or hydrated barium polyborate (Ba3B6O9(OH)6) which crystallizes in monoclinic system in the P2/c space group. The molecular structure analysis shows the presence of dominant BO4 unit and the hydrated nature of material. γ-BBO exhibits sharp absorption edge at 202 nm and highly transparency in the UV-Visible-NIR region. The peak at 347 nm in the emission spectrum is due to the presence of self-trapped exciton. The third order nonlinear optical properties and limiting behavior of low temperature barium borate in both pulsed and continuous wave regime were studied. The effective 2PA absorption coefficient of γ-BBO under ns pulse excitation is estimated to be 0.38 × 10-10 m/W. The nonlinear absorption coefficient, refractive index and optical susceptibility of the material in cw regime were found to be in the order of 10-5 m W-1, 10-12 m2 W-1, 10-6 esu respectively. In both regimes, low temperature phase barium borate exhibits better optical limiting properties than high temperature phase β-BBO.

  18. Soliton-Like Pulses in Vertical Granular Chain Under Gravity: Particle-Like or Wave-Like?

    Institute of Scientific and Technical Information of China (English)

    XU Ai-Guo; HONG Jongbae

    2001-01-01

    We numerically study the propagation, reflection and collision of soliton-like pulses in the vertical granular chain under gravity. For the pure granular chain system, during the propagation and reflection processes at the fixed end, it behaves like a particle. When it is reflected at the free end, it behaves as neither particle-like nor wave-like.When the strengths of the two colliding soliton-like pulses are close, they collide just like particles. When their strengths are greatly different, they collide just like waves. For the soliton behavior in the collision process, from particle-like to wave-like, there is a critical value θC for the ratio θ of the strengths of the two initial pulses. For the two-layer granular chain, if the mass of the grains in the second layeris less than that in the first layer, the soliton-like pulse in the first layer usually excites about [1/m] soliton-like pulses in the second layer.``

  19. Numerical simulation and experimental detection of leaky Lamb waves induced by pulse laser at air-solid interfaces

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on the thermoelastic mechanism of laser ultrasonic, the problems of the thermal conduction and the coupling between the motion of solid and fluid are solved by using the finite element method. And then the transient waveforms of leaky Lamb waves induced by pulse laser action on the air-aluminum interface are obtained. Experimental signals of laser-induced leaky Lamb waves at the air-alu- minum interface are detected by applying an our-developed detector, based on the light deflection principle. The dispersion and attenuation properties of leaky Lamb waves are analyzed through the phase spectral analysis.

  20. Non-invasive measurement of aortic pressure in patients: Comparing pulse wave analysis and applanation tonometry

    Directory of Open Access Journals (Sweden)

    M.U.R. Naidu

    2012-01-01

    Full Text Available Objective: The aim of the present study was to validate and compare novel methods to determine aortic blood pressure non-invasively based on Oscillometric Pulse Wave Velocity (PWV measurement using four limb-cuff pressure waveforms and two lead Electrocardiogram (ECG with a validated tonometric pulse wave analysis system in patients. Materials and Methods: After receiving the consent, in 49 patients with hypertension, coronary artery disease, diabetes mellitus, PWV, and central blood pressures were recorded in a randomised manner using both the oscillometric and tonometric devices. All recordings were performed 10 minutes after the patient lying comfortably in a noise-free temperature-controlled room. The test was performed between 09 am and 10 am after overnight fast. A minimum of three measurements were performed by the same skilled and trained operator. From the raw data obtained with two devices, software calculated the final vascular parameters. Results: A total of 49 patients (8 women and 41 men, of mean age 40.5 years (range: 19-81 years participated in the present study. After transforming the brachial pressures into aortic pressures, the correlation coefficient between the Aortic Systolic Pressure (ASP values obtained with two methods was 0.9796 (P<0.0001. The mean difference between ASP with two methods was 0.3 mm Hg. Similarly, Aortic Diastolic Pressure (ADP values obtained with two methods also correlated significantly with correlation coefficient of 0.9769 (P<0.0001. The mean difference of ADP was 0.2 mm Hg. In case of Aortic Pulse Pressure (APP, the mean difference was 0.1 mm Hg. All parameters of central aortic pressures obtained with two methods correlated significantly. Conclusion: The new method of transforming the Carotid Femoral PWV (cfPWV and brachial blood pressure values into aortic blood pressure values seems to be reasonably good. The significant correlation between the values obtained by tonometric device and

  1. Dynamic Behaviors of Materials under Ramp Wave Loading on Compact Pulsed Power Generators

    Science.gov (United States)

    Zhao, Jianheng; Luo, Binqiang; Wang, Guiji; Chong, Tao; Tan, Fuli; Liu, Cangli; Sun, Chengwei

    The technique using intense current to produce magnetic pressure provides a unique way to compress matter near isentrope to high density without obvious temperature increment, which is characterized as ramp wave loading, and firstly developed by Sandia in 1998. Firstly recent advances on compact pulsed power generators developed in our laboratory, such as CQ-4, CQ-3-MMAF and CQ-7 devices, are simply introduced here, which devoted to ramp wave loading from 50GPa to 200 GPa, and to ultrahigh-velocity flyer launching up to 30 km/s. And then, we show our progress in data processing methods and experiments of isentropic compression conducted on these devices mentioned above. The suitability of Gruneisen EOS and Vinet EOS are validated by isentropic experiments of tantalum, and the parameters of SCG constitutive equation of aluminum and copper are modified to give better prediction under isentropic compression. Phase transition of bismuth and tin are investigated under different initial temperatures, parameters of Helmholtz free energy and characteristic relaxation time in kinetic phase transition equation are calibrated. Supported by NNSF of China under Contract No.11327803 and 11176002

  2. A high-temperature superconducting millimeter wave detecting system based on pulse tube cryocooler

    Science.gov (United States)

    Chen, Jian; Wu, Peiheng; Nakajima, Kensuke; Yamashita, Tsutomu

    2004-10-01

    A millimeter (mm) wave broadband video detecting system using high temperature superconducting (HTS) junction and compact pulse tube cryocooler (PTC) has been studied. The lowest attainable temperature of the PTC is 42K and the operating temperature (T) can be adjusted by changing the pressure difference in the compressor. By measuring the linewidth of the Josephson oscillation as well as the dynamic range of the Josephson detector, it is found that the PTC has no excess noise compared with other kinds of cryostats such as liquid helium cryostats, and is very suitable for the applications in the mm wave detecting system. Furthermore, to improve the sensitivity of the system, the coupling efficiency of the system has been studied in detail. It is found that the coupling efficiency increases with the increase of RN linearly, and is better than 1% for RN of 1.7 Ohm. A sensitivity of about 318V/W has been obtained for the system based on the PTC and a junction with RN=1.7 Ohm and ICRN =1mV.

  3. Numerical assessment of time-domain methods for the estimation of local arterial pulse wave speed.

    Science.gov (United States)

    Alastruey, Jordi

    2011-03-15

    A local estimation of pulse wave speed c, an important predictor of cardiovascular events, can be obtained at arterial locations where simultaneous measurements of blood pressure (P) and velocity (U), arterial diameter (D) and U, flow rate (Q) and cross-sectional area (A), or P and D are available, using the PU-loop, sum-of-squares (∑(2)), lnDU-loop, QA-loop or new D(2)P-loop methods. Here, these methods were applied to estimate c from numerically generated P, U, D, Q and A waveforms using a visco-elastic one-dimensional model of the 55 larger human systemic arteries in normal conditions. Theoretical c were calculated from the parameters of the model. Estimates of c given by the loop methods were closer to theoretical values and more uniform within each arterial segment than those obtained using the ∑(2). The smaller differences between estimates and theoretical values were obtained using the D(2)P-loop method, with root-mean-square errors (RMSE) smaller than 0.18 ms(-1), followed by averaging the two c given by the PU- and lnDU-loops (RMSE elastic effects were small and nearby junctions were well-matched for forward-travelling waves. The ∑(2) performed better at proximal locations. PMID:21211799

  4. Pulse wave analysis in a 180-degree curved artery model: Implications under physiological and non-physiological inflows

    Science.gov (United States)

    Bulusu, Kartik V.; Plesniak, Michael W.

    2013-11-01

    Systolic and diastolic blood pressures, pulse pressures, and left ventricular hypertrophy contribute to cardiovascular risks. Increase of arterial stiffness due to aging and hypertension is an important factor in cardiovascular, chronic kidney and end-stage-renal-diseases. Pulse wave analysis (PWA) based on arterial pressure wave characteristics, is well established in clinical practice for evaluation of arterial distensibility and hypertension. The objective of our exploratory study in a rigid 180-degree curved artery model was to evaluate arterial pressure waveforms. Bend upstream conditions were measured using a two-component, two-dimensional, particle image velocimeter (2C-2D PIV). An ultrasonic transit-time flow meter and a catheter with a MEMS-based solid state pressure sensor, capable of measuring up to 20 harmonics of the observed pressure waveform, monitored flow conditions downstream of the bend. Our novel continuous wavelet transform algorithm (PIVlet 1.2), in addition to detecting coherent secondary flow structures is used to evaluate arterial pulse wave characteristics subjected to physiological and non-physiological inflows. Results of this study will elucidate the utility of wavelet transforms in arterial function evaluation and pulse wave speed. Supported by NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

  5. Transient and time-resolved four-wave mixing with collinear pump and probe pulses using the heterodyne technique

    DEFF Research Database (Denmark)

    Mecozzi, A.; Mørk, Jesper

    1998-01-01

    We review the recently proposed heterodyne technique for four-wave mixing experiments with collinear and co-polarized pulses. We discuss issues related to the parameters of the nonlinear dynamics of the sample that can be extracted by this technique....

  6. Energy-scalable temporal cleaning device for femtosecond laser pulses based on cross-polarized wave generation

    International Nuclear Information System (INIS)

    We report on a compact energy-scalable device for generating high-fidelity femtosecond laser pulses based on spatial filtering through a hollow-core fiber followed by a nonlinear crystal for cross polarized wave (XPW) generation. This versatile device is suited for temporal pulse cleaning over a wide range of input energies (from 0.1 to ≥10 mJ) and is successfully qualified on different ultrafast laser systems. Full characterization of the XPW output is presented. In particular, we demonstrate the generation of 1.6 mJ energy pulses starting from 11 mJ input pulse energy. The temporal contrast of the pulses is enhanced by more than 4 orders of magnitude. In addition, pulse shortening from 40 fs down to 15 fs Fourier-transform limit yields an overall peak-power transmission of up to 50%. This device not only serves as an integrated pulse contrast filter inside an ultrafast laser amplifier but also as a simple back-end solution for temporal post-compression of amplified pulses. (authors)

  7. Pulsed electromagnetic wave exposure induces ultrastructural damage and upregulated expression of heat shock protein 70 in the rat adenohypophysis.

    Science.gov (United States)

    Cheng, Kang; Ren, Dong-Qing; Yi, Jun; Zhou, Xiao-Guang; Yang, Wen-Qing; Chen, Yong-Bin; Li, Yong-Qiang; Huang, Xiao-Feng; Zeng, Gui-Ying

    2015-08-01

    The aim of the present study was to investigate the ultrastructural damage and the expression of heat shock protein 70 (HSP70) in the rat adenohypophysis following pulsed electromagnetic wave (PEMW) exposure. The rats were randomly divided into four groups: Sham PEMW exposure, 1 x 10(4) pulses of PEMW exposure, 1 x 10(5) pulses of PEMW exposure and 3 x 10(5) pulses of PEMW exposure. Whole body radiation of 1 x 10(4) pulses, 1 x 10(5) pulses and 3 x 10(5) pulses of PEMW were delivered with a field strength of 100 kV/m. The rats in each group (n=6 in each) were sacrificed 12, 24, 48 and 96 h after PEMW exposure. Transmission electron microscopy was then used to detect the ultrastructural changes and immunocytochemistry was used to examine the expression of HSP70. Cellular damage, including mitochondrial vacuolation occurred as early as 12 h after PEMW exposure.More severe cellular damages, including cell degeneration and necrosis, occurred 24 and 48 h after PEMW exposure. The PEMW-induced cellular damage increased as the number of PEMW pulses increased. In addition, the expression of HSP70 significantly increased following PEMW exposure and peaked after 12 h. These findings suggested that PEMW induced ultrastructural damages in the rat adenohypophysis and that HSP70 may have contributed to the PEMW-induced adenohypophyseal damage. PMID:25891763

  8. Discharge conditions for CW and pulse-modulated surface-wave plasmas in low-temperature sterilization

    Energy Technology Data Exchange (ETDEWEB)

    Xu, L [Department of Electrical and Electronic Engineering, Faculty of Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan); Terashita, F [Department of Electrical and Electronic Engineering, Faculty of Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan); Nonaka, H [Department of Electrical and Electronic Engineering, Faculty of Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan); Ogino, A [Department of Electrical and Electronic Engineering, Faculty of Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan); Nagata, T [Department of Microbiology and Immunology, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Hamamatsu 431-3192 (Japan); Koide, Y [Department of Microbiology and Immunology, Hamamatsu University School of Medicine, 1-20-1 Handa-yama, Hamamatsu 431-3192 (Japan); Nanko, S [Nissin Inc., 10-7 Kamei-cho, Takarazuka 665-0047 (Japan); Kurawaki, I [GMA Co. Ltd., 3898-1, Asaba, Fukuroi, 437-1101 (Japan); Nagatsu, M [Department of Electrical and Electronic Engineering, Faculty of Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561 (Japan)

    2006-01-07

    The discharge conditions required for low-temperature plasma sterilization were investigated using low-pressure surface-wave plasma (SWP). The discharge conditions for both continuous wave (CW) and pulse-modulated SWPs in low-temperature sterilization of Geobacillus stearothermophilus with a population of 1.5 x 10{sup 6} and 3.0 x 10{sup 6} were studied by varying the microwave input power from 500 W to 3 kW, and the effective plasma treatment time from 40 to 300 s. Results showed that sterilization was possible in a shorter treatment time using a higher microwave power for both CW and pulse-modulated SWPs. Pulse-modulated SWPs gave effective sterilization at a temperature roughly 10 to 20 deg. C below that of CW SWPs under the same average microwave power.

  9. Discharge conditions for CW and pulse-modulated surface-wave plasmas in low-temperature sterilization

    Science.gov (United States)

    Xu, L.; Terashita, F.; Nonaka, H.; Ogino, A.; Nagata, T.; Koide, Y.; Nanko, S.; Kurawaki, I.; Nagatsu, M.

    2006-01-01

    The discharge conditions required for low-temperature plasma sterilization were investigated using low-pressure surface-wave plasma (SWP). The discharge conditions for both continuous wave (CW) and pulse-modulated SWPs in low-temperature sterilization of Geobacillus stearothermophilus with a population of 1.5 × 106 and 3.0 × 106 were studied by varying the microwave input power from 500 W to 3 kW, and the effective plasma treatment time from 40 to 300 s. Results showed that sterilization was possible in a shorter treatment time using a higher microwave power for both CW and pulse-modulated SWPs. Pulse-modulated SWPs gave effective sterilization at a temperature roughly 10 to 20 °C below that of CW SWPs under the same average microwave power.

  10. Whistler wave radiation from a pulsed loop antenna located in a cylindrical duct with enhanced plasma density

    Energy Technology Data Exchange (ETDEWEB)

    Kudrin, Alexander V.; Shkokova, Natalya M. [Department of Radiophysics, University of Nizhny Novgorod, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Ferencz, Orsolya E. [MTA Research Centre for Astronomy and Earth Sciences, Csatkai E. u. 6–8, Sopron H-9400 (Hungary); Zaboronkova, Tatyana M. [Department of Radiophysics, University of Nizhny Novgorod, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Department of Nuclear Physics, R. E. Alekseev State Technical University of Nizhny Novgorod, 24 Minin St., Nizhny Novgorod 603950 (Russian Federation)

    2014-11-15

    Pulsed radiation from a loop antenna located in a cylindrical duct with enhanced plasma density is studied. The radiated energy and its distribution over the spatial and frequency spectra of the excited waves are derived and analyzed as functions of the antenna and duct parameters. Numerical results referring to the case where the frequency spectrum of the antenna current is concentrated in the whistler range are reported. It is shown that under ionospheric conditions, the presence of an artificial duct with enhanced density can lead to a significant increase in the energy radiated from a pulsed loop antenna compared with the case where the same source is immersed in the surrounding uniform magnetoplasma. The results obtained can be useful in planning active ionospheric experiments with pulsed electromagnetic sources operated in the presence of artificial field-aligned plasma density irregularities that are capable of guiding whistler waves.

  11. Laser-energy transfer and enhancement of plasma waves and electron beams by interfering high-intensity laser pulses.

    Science.gov (United States)

    Zhang, P; Saleh, N; Chen, S; Sheng, Z M; Umstadter, D

    2003-11-28

    The effects of interference due to crossed laser beams were studied experimentally in the high-intensity regime. Two ultrashort (400 fs), high-intensity (4 x 10(17) and 1.6 x 10(18) W/cm(2)) and 1 microm wavelength laser pulses were crossed in a plasma of density 4 x 10(19) cm(3). Energy was observed to be transferred from the higher-power to the lower-power pulse, increasing the amplitude of the plasma wave propagating in the direction of the latter. This results in increased electron self-trapping and plasma-wave acceleration gradient, which led to an increased number of hot electrons (by 300%) and hot-electron temperature (by 70%) and a decreased electron-beam divergence angle (by 45%), as compared with single-pulse illumination. Simulations reveal that increased stochastic heating of electrons may have also contributed to the electron-beam enhancement.

  12. Coherent control of optical four-wave mixing by two-color $\\omega$-$3\\omega$ ultrashort laser pulses

    CERN Document Server

    Serrat, C

    2004-01-01

    A theoretical investigation on the phase control of optical transient four-wave mixing interactions in two-level systems driven by two intense temporal coherent femtosecond laser pulses of central angular frequencies $\\omega$ and $3\\omega$ is reported. By solving the full Maxwell-Bloch equations beyond the slowly-varying envelope and rotating-wave approximations in the time domain, the parametric nonlinear coupling to the optical field at frequency $5\\omega$ is found to depend critically on the initial relative phase $\\phi$ of the two propagating pulses; the coupling is enhanced when the pulses interfere constructively in the center ($\\phi=0$), while it is nearly suppressed when they are out of phase ($\\phi=\\pi$).

  13. Pulse-front tilt for short-wavelength lasing by means of traveling-wave plasma-excitation.

    Science.gov (United States)

    Bleiner, Davide; Feurer, Thomas

    2012-12-20

    Generation of coherent short-wavelength radiation across a plasma column is dramatically improved under traveling-wave excitation (TWE). The latter is optimized when its propagation is close to the speed of light, which implies small-angle target-irradiation. Yet, short-wavelength lasing needs large irradiation angles in order to increase the optical penetration of the pump into the plasma core. Pulse-front back-tilt is considered to overcome such trade-off. In fact, the TWE speed depends on the pulse-front slope (envelope of amplitude), whereas the optical penetration depth depends on the wave-front slope (envelope of phase). Pulse-front tilt by means of compressor misalignment was found effective only if coupled with a high-magnification front-end imaging/focusing component. It is concluded that speed matching should be accomplished with minimal compressor misalignment and maximal imaging magnification.

  14. Characterization of an electrochemical mercury sensor using alternating current, cyclic, square wave and differential pulse voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Guerreiro, Gabriela V.; Zaitouna, Anita J.; Lai, Rebecca Y., E-mail: rlai2@unl.edu

    2014-01-31

    Graphical abstract: -- Highlights: •An electrochemical Hg(II) sensor based on T–Hg(II)–T sensing motif was fabricated. •A methylene blue-modified DNA probe was used to fabricate the sensor. •Sensor performance was evaluated using ACV, CV, SWV, and DPV. •The sensor behaves as a “signal-off” sensor in ACV and CV. •The sensor behaves as either a “signal-on” or “signal-off” sensor in SWV and DPV. -- Abstract: Here we report the characterization of an electrochemical mercury (Hg{sup 2+}) sensor constructed with a methylene blue (MB)-modified and thymine-containing linear DNA probe. Similar to the linear probe electrochemical DNA sensor, the resultant sensor behaved as a “signal-off” sensor in alternating current voltammetry and cyclic voltammetry. However, depending on the applied frequency or pulse width, the sensor can behave as either a “signal-off” or “signal-on” sensor in square wave voltammetry (SWV) and differential pulse voltammetry (DPV). In SWV, the sensor showed “signal-on” behavior at low frequencies and “signal-off” behavior at high frequencies. In DPV, the sensor showed “signal-off” behavior at short pulse widths and “signal-on” behavior at long pulse widths. Independent of the sensor interrogation technique, the limit of detection was found to be 10 nM, with a linear dynamic range between 10 nM and 500 nM. In addition, the sensor responded to Hg{sup 2+} rather rapidly; majority of the signal change occurred in <20 min. Overall, the sensor retains all the characteristics of this class of sensors; it is reagentless, reusable, sensitive, specific and selective. This study also highlights the feasibility of using a MB-modified probe for real-time sensing of Hg{sup 2+}, which has not been previously reported. More importantly, the observed “switching” behavior in SWV and DPV is potentially generalizable and should be applicable to most sensors in this class of dynamics-based electrochemical biosensors.

  15. Multi-soliton, multi-breather and higher order rogue wave solutions to the complex short pulse equation

    Science.gov (United States)

    Ling, Liming; Feng, Bao-Feng; Zhu, Zuonong

    2016-07-01

    In the present paper, we are concerned with the general analytic solutions to the complex short pulse (CSP) equation including soliton, breather and rogue wave solutions. With the aid of a generalized Darboux transformation, we construct the N-bright soliton solution in a compact determinant form, the N-breather solution including the Akhmediev breather and a general higher order rogue wave solution. The first and second order rogue wave solutions are given explicitly and analyzed. The asymptotic analysis is performed rigorously for both the N-soliton and the N-breather solutions. All three forms of the analytical solutions admit either smoothed-, cusped- or looped-type ones for the CSP equation depending on the parameters. It is noted that, due to the reciprocal (hodograph) transformation, the rogue wave solution to the CSP equation can be a smoothed, cusponed or a looped one, which is different from the rogue wave solution found so far.

  16. Left ventricular radial colour and longitudinal pulsed-wave tissue Doppler echocardiography in 39 healthy domestic pet rabbits.

    Science.gov (United States)

    Casamian-Sorrosal, Domingo; Saunders, Richard; Browne, William; Elliot, Sarah; Fonfara, Sonja

    2014-10-01

    This paper reports radial colour and longitudinal mitral annulus pulsed-wave tissue Doppler findings in a large cohort of healthy, adult pet rabbits. Thirty-nine rabbits (22 Dwarf Lops, 14 French Lops and three Alaskans) underwent conscious echocardiography. The median age of the rabbits was 22 months and the median weight was 2.8 kg (Dwarf Lop 2.4 kg/French Lop 6.0 kg). Adequate radial colour and longitudinal pulsed-wave tissue Doppler traces were obtained in 100% and 85% of cases, respectively. Most systolic tissue Doppler parameters were significantly higher in French Lops than in Dwarf Lops. Separation of mitral inflow diastolic waves was present in 40% of cases using conventional spectral Doppler and in >60% of cases using pulsed-wave tissue Doppler which could be beneficial when evaluating diastolic function in rabbits. This study can be used as a reference for normal echocardiographic tissue Doppler values for adult rabbits undergoing conscious echocardiography in clinical practice. PMID:25089025

  17. An experimental study of the interaction between a pulsed electron beam and a large-amplitude electromagnetic wave

    Science.gov (United States)

    Kalinin, Yu. A.; Starodubov, A. V.; Fokin, A. S.

    2015-01-01

    We experimentally investigate the interaction between an electron beam with a periodically varying diameter and a large-amplitude electromagnetic wave. The effect of different factors on the pulsed beam formation and current density in bunches is established. Compared with the electron beam deceleration circuits (low-voltage vircator systems), the generators based on pulsed turbulent beams have a broader band due to the formation of a large number of space charge bunches and an integral power efficiency that is higher by a factor of 2-2.5.

  18. Signal-Pressure Curves of Cascaded Four-Wave Mixing in Gas-Filled Capillary by fs Pulses

    Institute of Scientific and Technical Information of China (English)

    CHEN Bao-Zhen; HUANG Zu-Qia

    2005-01-01

    The theoretical framework for the cascaded four waves mixing (CFWM) in gas-filled capillary by fs pulses is constructed. Based on the theoretical framework, the signal-pressure curves (SPC) of the CFWM in gas-filled capillary by fs pulses are calculated. With a comparison between the theoretical and experimental SPC we have discussed the influence of the walk-off and Phase modulation on the SPC. At the same time, we have discussed the possible origin of the first three peaks of the SPC.

  19. Multi-soliton, multi-breather and higher-order rogue wave solutions to the complex short pulse equation

    CERN Document Server

    Ling, Liming; Zhu, Zuonong

    2015-01-01

    In the present paper, we are concerned with the general localized solutions for the complex short pulse equation including soliton, breather and rogue wave solutions. With the aid of a generalized Darboux transformation, we construct the $N$-bright soliton solution in a compact determinant form, then the $N$-breather solution including the Akhmediev breather and a general higher order rogue wave solution. The first- and second-order rogue wave solutions are given explicitly and illustrated by graphs. The asymptotic analysis is performed rigorously for both the $N$-soliton and the $N$-breather solutions. All three forms of the localized solutions admit either smoothed-, cusped- or looped-type ones for the CSP equation depending on the parameters. It is noted that, due to the reciprocal (hodograph) transformation, the rogue wave solution to the CSP equation is different from the one to the nonlinear Schr\\"odinger (NLS) equation, which could be a cusponed- or a looped one.

  20. A 1D pulse wave propagation model of the hemodynamics of calf muscle pump function.

    Science.gov (United States)

    Keijsers, J M T; Leguy, C A D; Huberts, W; Narracott, A J; Rittweger, J; van de Vosse, F N

    2015-07-01

    The calf muscle pump is a mechanism which increases venous return and thereby compensates for the fluid shift towards the lower body during standing. During a muscle contraction, the embedded deep veins collapse and venous return increases. In the subsequent relaxation phase, muscle perfusion increases due to increased perfusion pressure, as the proximal venous valves temporarily reduce the distal venous pressure (shielding). The superficial and deep veins are connected via perforators, which contain valves allowing flow in the superficial-to-deep direction. The aim of this study is to investigate and quantify the physiological mechanisms of the calf muscle pump, including the effect of venous valves, hydrostatic pressure, and the superficial venous system. Using a one-dimensional pulse wave propagation model, a muscle contraction is simulated by increasing the extravascular pressure in the deep venous segments. The hemodynamics are studied in three different configurations: a single artery-vein configuration with and without valves and a more detailed configuration including a superficial vein. Proximal venous valves increase effective venous return by 53% by preventing reflux. Furthermore, the proximal valves shielding function increases perfusion following contraction. Finally, the superficial system aids in maintaining the perfusion during the contraction phase and reduces the refilling time by 37%. PMID:25766693

  1. Multiscale entropy analysis of pulse wave velocity for assessing atherosclerosis in the aged and diabetic.

    Science.gov (United States)

    Wu, Hsien-Tsai; Hsu, Po-Chun; Lin, Cheng-Feng; Wang, Hou-Jun; Sun, Cheuk-Kwan; Liu, An-Bang; Lo, Men-Tzung; Tang, Chieh-Ju

    2011-10-01

    This study proposed a dynamic pulse wave velocity (PWV)-based biomedical parameter in assessing the degree of atherosclerosis for the aged and diabetic populations. Totally, 91 subjects were recruited from a single medical institution between July 2009 and October 2010. The subjects were divided into four groups: young healthy adults (Group 1, n = 22), healthy upper middle-aged adults (Group 2, n = 28), type 2 diabetics with satisfactory blood sugar control (Group 3, n = 21), and unsatisfactory blood sugar control (Group 4, n = 20). A self-developed six-channel electrocardiography (ECG)-PWV-based equipment was used to acquire 1000 successive recordings of PWV(foot) values within 30 min. The data, thus, obtained were analyzed with multiscale entropy (MSE). Large-scale MSE index (MEI(LS)) was chosen as the assessment parameter. Not only did MEI(LS) successfully differentiate between subjects in Groups 1 and 2, but it also showed a significant difference between Groups 3 and 4. Compared with the conventional parameter of PWV(foot) and MEI on R-R interval [i.e., MEI(RRI)] in evaluating the degree of atherosclerotic change, the dynamic parameter, MEI(LS) (PWV), could better reflect the impact of age and blood sugar control on the progression of atherosclerosis. PMID:21693413

  2. Relations between diabetes, blood pressure and aortic pulse wave velocity in haemodialysis patients

    DEFF Research Database (Denmark)

    Peters, Christian Daugaard; Kjærgaard, Krista Dybtved; Dzeko, Mirela;

    Diabetes (DM) is common in haemodialysis (HD) patients and affects both blood pressure (BP) and arterial stiffness. Carotid femoral pulse wave velocity (PWV) reflects the stiffness of the aorta and is regarded as a strong risk factor for cardiovascular (CV) mortality in HD patients. However, PWV...... is highly influenced by the BP-level. Higher PWV-values among HD patients with DM could reflect a higher BP-level rather than increased arterial stiffness. The aim of this study was to investigate the effect of DM on BP and PWV in a group of HD patients. BP and PWV were measured in 66 HD patients without DM...... (HD) and 32 HD patients with DM (HD+DM). The SphygmoCor system was used for estimation of PWV. HD-duration, age, gender and BP medication were similar in the two groups. Mean DM-duration was 23±11 years and 25(78%) had type 2 DM. HD+DM had higher BMI (26±5 vs. 29±5 kg/m2, p=0.02), systolic BP (142...

  3. Applicability of the polynomial chaos expansion method for personalization of a cardiovascular pulse wave propagation model.

    Science.gov (United States)

    Huberts, W; Donders, W P; Delhaas, T; van de Vosse, F N

    2014-12-01

    Patient-specific modeling requires model personalization, which can be achieved in an efficient manner by parameter fixing and parameter prioritization. An efficient variance-based method is using generalized polynomial chaos expansion (gPCE), but it has not been applied in the context of model personalization, nor has it ever been compared with standard variance-based methods for models with many parameters. In this work, we apply the gPCE method to a previously reported pulse wave propagation model and compare the conclusions for model personalization with that of a reference analysis performed with Saltelli's efficient Monte Carlo method. We furthermore differentiate two approaches for obtaining the expansion coefficients: one based on spectral projection (gPCE-P) and one based on least squares regression (gPCE-R). It was found that in general the gPCE yields similar conclusions as the reference analysis but at much lower cost, as long as the polynomial metamodel does not contain unnecessary high order terms. Furthermore, the gPCE-R approach generally yielded better results than gPCE-P. The weak performance of the gPCE-P can be attributed to the assessment of the expansion coefficients using the Smolyak algorithm, which might be hampered by the high number of model parameters and/or by possible non-smoothness in the output space. PMID:25377937

  4. Chirped solitary pulses for a nonic nonlinear Schrödinger equation on a continuous-wave background

    Science.gov (United States)

    Triki, Houria; Porsezian, K.; Choudhuri, Amitava; Dinda, P. Tchofo

    2016-06-01

    A class of derivative nonlinear Schrödinger equation with cubic-quintic-septic-nonic nonlinear terms describing the propagation of ultrashort optical pulses through a nonlinear medium with higher-order Kerr responses is investigated. An intensity-dependent chirp ansatz is adopted for solving the two coupled amplitude-phase nonlinear equations of the propagating wave. We find that the dynamics of field amplitude in this system is governed by a first-order nonlinear ordinary differential equation with a tenth-degree nonlinear term. We demonstrate that this system allows the propagation of a very rich variety of solitary waves (kink, dark, bright, and gray solitary pulses) which do not coexist in the conventional nonlinear systems that have appeared so far in the literature. The stability of the solitary wave solution under some violation on the parametric conditions is investigated. Moreover, we show that, unlike conventional systems, the nonlinear Schrödinger equation considered here meets the special requirements for the propagation of a chirped solitary wave on a continuous-wave background, involving a balance among group velocity dispersion, self-steepening, and higher-order nonlinearities of different nature.

  5. Generation of ultrasonic wave by a pulsed Nd:YAG laser and application of detection of defects

    International Nuclear Information System (INIS)

    Conventional ultrasonic evaluation is the contacting method by using transducer and couplant. Thus it not applied the material with high temperature, movement. Substitutionally a laser pulse irradiated on a material generates acoustic wave. In this paper, piezoelectric transducer detects ultrasonic waveforms. We have experimented in low laser energy for nondestructive evaluation. And theoretical waveform is compared with experimental waveform. And longitudinal, shear wave are detected and their sound velocity are obtained exactly. Also, in application, we discussed how flaw detection might be achieved with laser-generated ultrasound in aluminum plate with drill hole.

  6. A Clinical Study of the Pulse Wave Characteristics at the Three Pulse Diagnosis Positions of Chon, Gwan and Cheok

    Directory of Open Access Journals (Sweden)

    Young J. Jeon

    2011-01-01

    Full Text Available In this work, we analyze the baseline, signal strength, aortic augmentation index (AIx, radial AIx, time to reflection and P_T2 at Chon, Gwan, and Cheok, which are the three pulse diagnosis positions in Oriental medicine. For the pulse measurement, we used the SphygmoCor apparatus, which has been widely used for the evaluation of the arterial stiffness at the aorta. By two-way repeated measures analysis of variance, we tested two independent measurements for repeatability and investigated their mean differences among Chon, Gwan and Cheok. To characterize further the parameters that were shown to be different between each palpation position, we carried out Duncan's test for the multiple comparisons. The baseline and signal strength were statistically different (<.05 among Chon, Gwan and Cheok, respectively, which supports the major hypothesis of Oriental medicine that all of the three palpation positions contain different clinical information. On the other hand, aortic AIx and time to reflection were found to be statistically different between Chon and the others, and radial AIx and P_T2 did not show any difference between pulse positions. In the clinical sense, however, the aortic AIx at each palpation position was found to fall within the 90% confidence interval of normal arterial compliance. The results of the multiple comparisons indicate that the parameters of arterial stiffness were independent of the palpation positions. This work is the first attempt to characterize quantitatively the pulse signals at Chon, Gwan and Cheok with some relevant parameters extracted from the SphygmoCor apparatus.

  7. Annihilation and creation of rotating waves by a local light pulse in a protoplasmic droplet of the Physarum plasmodium

    Science.gov (United States)

    Takagi, Seiji; Ueda, Tetsuo

    2010-06-01

    Pattern dynamics plays a fundamental role in biological functions from cell to organ in living systems, and the appearance of rotating waves can lead to pathological situations. Basic dynamics of rotating waves of contraction-relaxation activity under local perturbation is studied in a newly developed protoplasmic droplet of the Physarum plasmodium. A light pulse is applied by irradiating circularly a quarter of the droplet showing a single rotating wave. The oscillation pattern changes abruptly only when the irradiation is applied at a part of the droplet near the maximal contraction. The abrupt changes are as follows: the rotating wave disappears or is displaced when the irradiation area is very close to the center of the rotating wave, while new rotating waves are created when the irradiation area is far from the center of the rotating wave. These results support the hypothesis that the phase response curve has a discontinuous change (type 0 resetting) from delay to advance around the maximal contraction. The significance of the results is discussed in relation to “vulnerability” in excitable media and biological systems in general.

  8. The effect of low-intensity pulsed sound waves delivered by the Exogen device on Staphylococcus aureus morphology and genetics

    OpenAIRE

    Ayan, İrfan; ASLAN, Gönül; ÇÖMELEKOĞLU, Ülkü; Yılmaz, Nejat; ÇOLAK, Mehmet

    2004-01-01

    Objectives: We investigated the effect of low-intensity pulsed sound waves delivered by the Exogen device, which is recommended for the treatment of delayed union and nonunion in orthopedic surgery, on the colony number, antimicrobial susceptibility, bacterial morphology, and genetics of Staphylococcus aureus, which is a frequent pathogen in orthopedic infections. Methods: Thirty tubes containing 0.5 McFarland suspensions of S. aureus (ATCC 25923) were used. Fifteen tubes forming the test ...

  9. Association of hypertension with physical factors of wrist pulse waves using a computational approach: a pilot study

    OpenAIRE

    Lee, Bum Ju; Jeon, Young Ju; Ku, Boncho; Kim, Jaeuk U.; Bae, Jang-Han; Kim, Jong Yeol

    2015-01-01

    Background The objectives of this pilot study were to examine the association between hypertension and physical factors of wrist pulse waves to avoid subjective diagnoses in Traditional Chinese Medicine (TCM) and Traditional Korean Medicine (TKM). An additional objective was to assess the predictive power of individual and combined physical factors in order to identify the degree of agreement between diagnosis accuracies using physical factors and using a sphygmomanometer in the prediction of...

  10. The Relationship among Pulse Wave Velocity, Ankle-Brachial Pressure Index and Heart Rate Variability in Adult Males

    OpenAIRE

    Ahn, Jeong-Hwan; Kong, Mihee

    2011-01-01

    Background Pulse wave velocity (PWV) and ankle-brachial pressure index (ABI) are non-invasive tools to measure atherosclerosis and arterial stiffness. Heart rate variability (HRV) has proven to be a non-invasive powerful tool in the investigation of the autonomic cardiovascular control. Therefore, the purpose of this study was to determine the relationship among PWV, ABI, and HRV parameters in adult males. Methods The study was carried out with 117 males who visited a health care center from ...

  11. Different photodynamic effect between continuous wave and pulsed laser irradiation modes in k562 cells in vitro

    Science.gov (United States)

    Klimenko, V. V.; Bogdanov, A. A.; Knyazev, N. A.; Rusanov, A. A.; Dubina, M. V.

    2014-10-01

    Photodynamic therapy is a cancer treatment method is used primarily continuous mode laser radiation. At high power density irradiation occurs intense consumption of molecular oxygen and this caused hypoxic tumor tissue, which leads to inefficiency PDT. In this paper, pulsed and continuous irradiation modes during PDT photosensitizer Radachlorin were compared. A mathematical model for the generation of singlet oxygen 1O2 in tumor cells during photodynamic therapy with tissue oxygenation was developed. Our study theoretically and experimentally demonstrates the increased singlet oxygen generation efficiency in a pulsed irradiation mode compared to continuous wave mode with the same power density 20mW/cm2. Experimental in vitro showed that pulsed irradiation mode mostly induces apoptosis k562 tumor cells at irradiation doses of k562 1.25 - 2.5J/cm2 while the continuous mode induced necrosis.

  12. The Marriage of Spectroscopy and Dynamics: Chirped-Pulse Fourier-Transform Mm-Wave Cp-Ft Spectroscopy in Pulsed Uniform Supersonic Flows

    Science.gov (United States)

    Abeysekera, Chamara; Oldham, James M.; Suits, Arthur G.; Park, G. Barratt; Field, Robert W.

    2012-06-01

    A new experimental scheme is presented that combines two powerful emerging technologies: chirped-pulse Fourier-transform mm-Wave spectroscopy and pulsed uniform supersonic flows. It promises a nearly universal detection method that can deliver quantitative isomer, conformer, and vibrational level specific detection, characterization of unstable reaction products and intermediates, and perform unique spectroscopic, kinetics, and dynamics measurements. Chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy, pioneered by Pate and coworkers, allows rapid acquisition of broadband microwave spectrum through advancements in waveform generation and oscilloscope technology. This revolutionary approach has successfully been adapted to higher frequencies by the Field group at MIT. Our new apparatus will exploit amplified chirped pulses in the range of 26-40 GHz, in combination with a pulsed uniform supersonic flow from a Laval nozzle. This nozzle source, pioneered by Rowe, Sims, and Smith for low temperature kinetics studies, produces thermalized reactants at high densities and low temperatures perfectly suitable for reaction dynamics experiments studied using the CP-mmW approach. This combination of techniques shall enhance the thousand-fold improvement in data acquisition rate achieved in the CP method by a further 2-3 orders of magnitude. A pulsed flow alleviates the challenges of continuous uniform flow, e.g. large gas loads and reactant consumption rates. In contrast to other pulsed Laval systems currently in use, we will use a fast piezo valve and small chambers to achieve the desired pressures while minimizing the gas load, so that a 10 Hz repetition rate can be achieved with one turbomolecular pump. The proposed technique will be suitable for many diverse fields, including fundamental studies in spectroscopy and reaction dynamics, reaction kinetics, combustion, atmospheric chemistry, and astrochemistry. We expect a significant advancement in the ability to

  13. Comparison of pulse wave velocity assessed by three different techniques: Arteriograph, Complior, and Echo-tracking.

    Science.gov (United States)

    Mihalcea, Diana J; Florescu, Maria; Suran, Berenice M C; Enescu, Oana A; Mincu, Raluca I; Magda, Stefania; Patrascu, Natalia; Vinereanu, Dragos

    2016-04-01

    Arterial stiffness estimated by pulse wave velocity (PWV) is an independent predictor of cardiovascular morbidity and mortality. Although recommended by the current guidelines, clinical applicability of this parameter is difficult, due to differences between the various techniques used to measure it and to biological variability. Our aim was to compare PWV assessed by 3 different commercially available systems. 100 subjects (51 ± 16 years, 45 men) were evaluated using the 3 methods: an oscillometric technique (Arteriograph, PWV-A); a piezo-electric method (Complior, PWV-C); and an high-resolution ultrasound technique implemented with an Echo-tracking system (Aloka, PWV-E). Conventional biological markers were measured. Correlations of PWV measured by the 3 methods were poor (r = 0.39, r = 0.39, and r = 0.31 for PWV-A vs. PWV-C, PWV-A vs. PWV-E, and PWV-C vs. PWV-E, respectively, all p < 0.05). By Bland-Altman analysis, mean difference (±SD) of PWV-A vs. PWV-C was -1.9 ± 2.0 m/s, of PWV-A vs. PWV-E -3.6 ± 1.9 m/s, and of PWV-C vs. PWV-E -2.7 ± 1.9 m/s, with a wide coefficient of variation (22.3, 25.7, and 25.7 %, respectively). As expected, PWV-A, PWV-C, and PWV-E correlated with other arterial stiffness parameters, such as intima-media thickness (r = 0.22, r = 0.22, and r = 0.36, respectively), E p (r = 0.37, r = 0.26, and r = 0.94, respectively), and augmentation index measured by Arteriograph method (r = 0.66, r = 0.35, and r = 0.26, respectively); all p < 0.05. Assessment of PWV is markedly dependent on the technique used to measure it, related to various methods for measuring traveled distance of the arterial wave. Our results suggest the urgent need to establish reference values of PWV for each of these techniques, separately, to be used in routine clinical practice.

  14. Pulse Wave Velocity and Cardiac Output vs. Heart Rate in Patients with an Implanted Pacemaker Based on Electric Impedance Method Measurement

    Science.gov (United States)

    Soukup, Ladislav; Vondra, Vlastimil; Viščor, Ivo; Jurák, Pavel; Halámek, Josef

    2013-04-01

    The methods and device for estimation of cardiac output and measurement of pulse wave velocity simultaneously is presented here. The beat-to-beat cardiac output as well as pulse wave velocity measurement is based on application of electrical impedance method on the thorax and calf. The results are demonstrated in a study of 24 subjects. The dependence of pulse wave velocity and cardiac output on heart rate during rest in patients with an implanted pacemaker was evaluated. The heart rate was changed by pacemaker programming while neither exercise nor drugs were applied. The most important result is that the pulse wave velocity, cardiac output and blood pressure do not depend significantly on heart rate, while the stroke volume is reciprocal proportionally to the heart rate.

  15. Pulse Wave Velocity and Cardiac Output vs. Heart Rate in Patients with an Implanted Pacemaker Based on Electric Impedance Method Measurement

    International Nuclear Information System (INIS)

    The methods and device for estimation of cardiac output and measurement of pulse wave velocity simultaneously is presented here. The beat-to-beat cardiac output as well as pulse wave velocity measurement is based on application of electrical impedance method on the thorax and calf. The results are demonstrated in a study of 24 subjects. The dependence of pulse wave velocity and cardiac output on heart rate during rest in patients with an implanted pacemaker was evaluated. The heart rate was changed by pacemaker programming while neither exercise nor drugs were applied. The most important result is that the pulse wave velocity, cardiac output and blood pressure do not depend significantly on heart rate, while the stroke volume is reciprocal proportionally to the heart rate.

  16. Ecocardiografia modo Doppler pulsado em gatos clinicamente sadios Pulsed wave Doppler echocardiography in clinically healthy cats

    Directory of Open Access Journals (Sweden)

    R.O. Carvalho

    2006-06-01

    Full Text Available Estudou-se o fluxo sangüíneo através das quatro valvas cardíacas em 30 gatos clinicamente sadios, com idade entre um e cinco anos e peso médio de 4,08kg, por meio da ecocardiografia modo Doppler pulsado. Foram medidas a velocidade máxima e a velocidade média dos fluxos, e realizou-se uma análise qualitativa dos seus perfis. Os animais foram sedados pela combinação de quetamina (12mg/kg e acepromazina (0,04mg/kg, aplicados por via intramuscular. Observou-se correlação positiva entre os parâmetros avaliados e a freqüência cardíaca, com exceção daqueles medidos no fluxo da valva aórtica. Não se observou correlação entre velocidades máxima e média e freqüência cardíaca e entre aquelas e peso corporal, e não houve diferença entre sexos.Pulsed wave Doppler echocardiography was used to study blood flow across the cardiac valves in 30 five-year-old cats (average body weight = 4.08kg. Animals were sedated using a combination of ketamin (12mg/kg, IM and acepromazin (0.04mg/kg, IM. Peak and mean velocities were determined, and blood flow patterns were recorded at the four cardiac valves. All variables, except those characterizing aortic valve flow, were positively correlated with heart rate. Blood flow variables were not correlated, however, with body weight; and there were no differences between males and females.

  17. Potential Role of Vegetarianism on Nutritional and Cardiovascular Status in Taiwanese Dialysis Patients: A Case-Control Study

    Science.gov (United States)

    Chen, Mei-Yin; Huang, Chien-Wei; Chen, Nai-Ching; Wu, Chien-Hsing; Hsu, Chih-Yang; Chou, Kang-Ju; Lee, Po-Tsang; Fang, Hua-Chang; Chen, Chien-Liang

    2016-01-01

    Background & Objectives Cardiovascular disease remains the most common cause of death for patients on chronic dialysis. End stage renal disease patients undergoing dialysis imposed to reduce phosphorus intake, which likely contributes to development of vegetarian diet behaviors. Vegetarian diets are often lower in protein content, in contradiction to the recommendation that a high protein diet is followed by patients undergoing dialysis. The purpose of the study was to investigate the effects of a vegetarian diet on the nutritional and cardiovascular status of dialysis patients. Design, Setting, Participants, Measurements A study of 21 vegetarian dialysis patients and 42 age- and sex-matched non-vegetarian dialysis patients selected as controls was conducted in the Kaohsiung Veterans General Hospital. Brachial-ankle pulse wave velocity and biochemistry data including total homocysteine levels, serum lipid profiles, high-sensitivity C-reactive protein, vitamin D levels, albumin, and normalized protein catabolic rate were measured. Results Compared with the non-vegetarian control group, vegetarian subjects had lower body weight, body mass index, serum phosphate, blood urea nitrogen, serum creatinine, vitamin D, uric acid, albumin, and normalized protein catabolic rate (p vegetarian group showed higher brachial-ankle pulse wave velocity than the non-vegetarian group (1926.95 ± 456.45 and 1684.82 ± 309.55 cm/sec, respectively, p vegetarian diet remained an independent risk factor for brachial-ankle pulse wave velocity. Conclusions The present study revealed that patients on dialysis who follow vegetarian diets may experience subclinical protein malnutrition and vitamin D deficiency that could offset the beneficial cardiovascular effects of vegetarianism. PMID:27295214

  18. Potential Role of Vegetarianism on Nutritional and Cardiovascular Status in Taiwanese Dialysis Patients: A Case-Control Study.

    Directory of Open Access Journals (Sweden)

    Shih-Hsiang Ou

    Full Text Available Cardiovascular disease remains the most common cause of death for patients on chronic dialysis. End stage renal disease patients undergoing dialysis imposed to reduce phosphorus intake, which likely contributes to development of vegetarian diet behaviors. Vegetarian diets are often lower in protein content, in contradiction to the recommendation that a high protein diet is followed by patients undergoing dialysis. The purpose of the study was to investigate the effects of a vegetarian diet on the nutritional and cardiovascular status of dialysis patients.A study of 21 vegetarian dialysis patients and 42 age- and sex-matched non-vegetarian dialysis patients selected as controls was conducted in the Kaohsiung Veterans General Hospital. Brachial-ankle pulse wave velocity and biochemistry data including total homocysteine levels, serum lipid profiles, high-sensitivity C-reactive protein, vitamin D levels, albumin, and normalized protein catabolic rate were measured.Compared with the non-vegetarian control group, vegetarian subjects had lower body weight, body mass index, serum phosphate, blood urea nitrogen, serum creatinine, vitamin D, uric acid, albumin, and normalized protein catabolic rate (p < 0.05. The vegetarian group showed higher brachial-ankle pulse wave velocity than the non-vegetarian group (1926.95 ± 456.45 and 1684.82 ± 309.55 cm/sec, respectively, p < 0.05. After adjustment for age, albumin, pre-dialysis systolic blood pressure, and duration of dialysis, vegetarian diet remained an independent risk factor for brachial-ankle pulse wave velocity.The present study revealed that patients on dialysis who follow vegetarian diets may experience subclinical protein malnutrition and vitamin D deficiency that could offset the beneficial cardiovascular effects of vegetarianism.

  19. Picosecond pulses of coherent MM-wave radiation in a photoinjector-driven waveguide free-selected laser

    Energy Technology Data Exchange (ETDEWEB)

    Fochs, S.N.; Le Sage, G.P.; Feng, L. [Univ. of California, Davis, CA (United States)] [and others

    1995-12-31

    A 5 MeV, high repetition rate (2.142 GHz in burst mode), high brightness, tabletop photoinjector is currently under construction at the UC Davis Department of Applied Science, on the LLNL site. Ultrashort pulses of coherent synchrotron radiation can be generated by transversally accelerating the electron beam with a wiggler in either metallic or dielectric-loaded waveguide FEL structures. This interaction is investigated theoretically and experimentally. Subpicosecond photoelectron bunches will be produced in the photoinjector by irradiating a high quantum efficiency Cs{sub 2}Te (Cesium Telluride) photocathode with a train of 100 UV (210 nm), ultra-short (250 fs) laser pulses. These bunches will be accelerated in a 1-1/2 cell {pi}-mode X-band RF gun e energized by a 20 MW, 8,568 GHz SLAC klystron. The peak current is 0.25 kA (0.25 nC, 1 ps), with a normalized beam emittance {epsilon}{sub n}<2.5 {pi} mm-mrad. This prebunched electron beam is then transversally accelerated in a cylindrical waveguide by a 30-mm period, 10 period long helical wiggler. The peak wiggler field is adjusted to 8.5 kG, so that the group velocity of the radiated electromagnetic waves matches the axial velocity of the electron bunch (grazing condition, zero slippage). Chirped output pulses in excess of 2 MW power are predicted, with an instantaneous bandwidth extending from 125 GHz to 225 GHz and a pulse duration of 15 ps (HWHM). To produce even shorter pulses, a dielectric-loaded waveguide can be used. The dispersion relation of this waveguide structure has an inflection point (zero group velocity dispersion). If the grazing condition is satisfied at this point, the final output pulse duration is no longer determined by slippage, or by group velocity dispersion and bandwidth, but by higher-order dispersive effects yielding transform-limited pulses.

  20. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    Directory of Open Access Journals (Sweden)

    Jung Nikolai H

    2012-11-01

    Full Text Available Abstract Background Transcranial magnetic stimulation (TMS commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor hand area (M1-HAND, if the induced tissue current has a posterior-to-anterior (PA or anterior-to-posterior (AP direction. Here we tested whether similar direction-specific effects could be elicited in M1-HAND using TMS pulses with a half-sine wave configuration. Results In 10 young participants, we applied half-sine pulses to the right M1-HAND which elicited PA or AP currents with respect to the orientation of the central sulcus. Measurements of the motor evoked potential (MEP revealed that PA half-sine stimulation resulted in lower resting motor threshold (RMT than AP stimulation. When stimulus intensity (SI was gradually increased as percentage of maximal stimulator output, the stimulus–response curve (SRC of MEP amplitude showed a leftward shift for PA as opposed to AP half-sine stimulation. Further, MEP latencies were approximately 1 ms shorter for PA relative to AP half-sine stimulation across the entire SI range tested. When adjusting SI to the respective RMT of PA and AP stimulation, the direction-specific differences in MEP latencies persisted, while the gain function of MEP amplitudes was comparable for PA and AP stimulation. Conclusions Using half-sine pulse configuration, single-pulse TMS elicits consistent direction-specific effects in M1-HAND that are similar to TMS with monophasic pulses. The longer MEP latency for AP half-sine stimulation suggests that PA and AP half-sine stimulation preferentially activates different sets of cortical neurons that are involved in the generation of different corticospinal descending volleys.

  1. High-power, mid-infrared, picosecond pulses generated by compression of a CO2 laser beat-wave in GaAs

    CERN Document Server

    Pigeon, J J; Joshi, C

    2015-01-01

    We report on the generation of a train of ~ 2 ps, 10 um laser pulses via multiple four-wave mixing and compression of an infrared laser beat-wave propagating in the negative group velocity dispersion region of bulk GaAs and a combination of GaAs and NaCl. The use of a 200 ps, 106 GHz beat-wave, produced by combining laser pulses amplified on the 10P(20) and 10P(16) transition of a CO2 laser, provides a novel method for generating high-power, picosecond, mid-IR laser pulses at a high repetition rate. By using 165 and 882 GHz beat-waves we show that cascaded phase-mismatched difference frequency generation plays a significant role in the four-wave mixing process in GaAs.

  2. Potential of M-Wave Elicited by Double Pulse for Muscle Fatigue Evaluation in Intermittent Muscle Activation by Functional Electrical Stimulation for Motor Rehabilitation

    Directory of Open Access Journals (Sweden)

    Naoto Miura

    2016-01-01

    Full Text Available Clinical studies on application of functional electrical stimulation (FES to motor rehabilitation have been increasing. However, muscle fatigue appears early in the course of repetitive movement production training by FES. Although M-wave variables were suggested to be reliable indices of muscle fatigue in long lasting constant electrical stimulation under the isometric condition, the ability of M-wave needs more studies under intermittent stimulation condition, because the intervals between electrical stimulations help recovery of muscle activation level. In this paper, M-waves elicited by double pulses were examined in muscle fatigue evaluation during repetitive movements considering rehabilitation training with surface electrical stimulation. M-waves were measured under the two conditions of repetitive stimulation: knee extension force production under the isometric condition and the dynamic movement condition by knee joint angle control. Amplitude of M-wave elicited by the 2nd pulse of a double pulse decreased during muscle fatigue in both measurement conditions, while the change in M-waves elicited by single pulses in a stimulation burst was not relevant to muscle fatigue in repeated activation with stimulation interval of 1 s. Fatigue index obtained from M-waves elicited by 2nd pulses was suggested to provide good estimation of muscle fatigue during repetitive movements with FES.

  3. Relationship between non-dipper hypertension and arteriosclerosis in the elderly

    Institute of Scientific and Technical Information of China (English)

    陈策

    2014-01-01

    Objective To investigate the influence of non-dipper blood pressure rhythm on peripheral atherosclerosis in elderly hypertensive patients.Methods The 199 elderly hypertensive patients with 24-hour average systolic blood pressure<140 mmH g were selected.Body mass index(BMI),glycosylated hemoglobin,blood lipids,uric acid,creatinine,Brachial ankle pulse wave velocity(ba PWV),ankle arm index(ABI)and 24-hour ambulatory blood pressure monitoring were tested and calculated.The elderly patients were divided into dipper hypertensive group(n=95),and non-dipper hypertensive

  4. Metabolic Syndrome-Associated Risk Factors and High-Sensitivity C-Reactive Protein Independently Predict Arterial stiffness in 9903 Subjects With and Without Chronic Kidney Disease

    OpenAIRE

    Tsai, Sung-Sheng; Lin, Yu-Sheng; Lin, Chia-Pin; Hwang, Jawl-Shan; Wu, Lung-Sheng; Chu, Pao-Hsien

    2015-01-01

    Abstract Metabolic syndrome (MS), high-sensitivity C-reactive protein (hs-CRP), and chronic kidney disease (CKD) are related to cardiovascular diseases. Although MS is common in CKD subjects, the contribution of MS-associated risk factors and hs-CRP to arterial stiffness in CKD has not been well studied. In this cross-sectional cohort study, we enrolled 9903 subjects who underwent brachial-ankle pulse wave velocity (baPWV) measurements from our database of Health Care Center. CKD was defined ...

  5. Impact of menaquinone-4 supplementation on coronary artery calcification and arterial stiffness: an open label single arm study

    OpenAIRE

    Ikari, Yuji; Torii, Sho; Shioi, Atsushi; Okano, Toshio

    2016-01-01

    Background Dietary intake of vitamin K has been reported to reduce coronary artery calcification (CAC) and cardiovascular events. However, it is unknown whether supplemental menaquinone (MK)-4 can reduce CAC or arterial stiffness. To study the effect of MK-4 supplementation on CAC and brachial ankle pulse wave velocity (baPWV). Methods This study is a single arm design to take 45 mg/day MK-4 daily as a therapeutic drug for 1 year. Primary endpoint was CAC score determined using 64-slice multi...

  6. The Associations of Coping Mechanism with Arterial Stiffness in Hwa-Byung Patients

    OpenAIRE

    Lee, Yu Jin; Baek, Kyung Won; Yun, Kyu Wol; Lim, Wonshin; Lim, Weonjeong

    2009-01-01

    Objective The goal of this study is to assess the relationship between stress coping mechanisms and the risk of atherosclerosis in patients with Hwa-Byung. Methods The Korean version of the Ways of Coping Checklist (WOCC) was administered to 50 patients with Hwa-Byung (49.1±10.1 years, 6 males). Brachial-ankle pulse wave velocity (baPWV) and serum cholesterol level were assessed in all participants. Results After controlling for age, sex, diagnosis of hypertension, Body Mass Index (BMI), and ...

  7. Evaluation of cellular effects of pulsed and continuous wave radiofrequency radiation

    International Nuclear Information System (INIS)

    Full text: In less than twenty years, the mobile telephone has gone from being rare, expensive equipment of the business elite to a pervasive, low-cost personal item. Since the introduction of mobile phones, concerns have been raised about the potential detrimental impacts on living beings from regular use. The first 'modern' network technology on second generation cellular technology was launched in 1991 in Finland on the Global System for Mobile Communications (GSM) standard. This study evaluates cellular effects of, both, continuous (CW) and pulsed GSM modulated waves (PW). Continuous cell culture of Chinese hamster lung cells, line V79, was used in this study. Cell growth and colony forming ability (CFA) was analyzed after 1, 2 and 3 hours of exposure to the both frequency fields, 935 MHz CW and 915 MHz PW. Selected frequency fields were generated inside gigahertz transversal electromagnetic mode cell (GTEM) equipped with the signal generators. Hewlett Packard HP8657A signal generator was used to generate CW 935 MHz frequency field. Anritzu MS2711B spectrum analyzer with tracking generator and Micro devices RF 3146 power amplifier module generated PW radiofrequency field of 915 MHz. Averaged specific absorption rate (SAR) belonging to the CW 935 MHz frequency field was calculated to be 0.12 W/kg, and for GSM modulated 915 MHz field was 0.23 W/kg. Cell samples were irradiated in triplicate. The sham exposed control cell samples were included in the study. The temperature inside the exposure set-up was recorded in ten-minute intervals through the irradiation treatment. Both, sham-exposed and exposed cell samples were kept in the same condition, except in the time of irradiation for experimental samples when signal generator was switched on. To determine cell growth, V79 samples were plated in concentration of 1x104cells/mL. Cells were maintained in the standard laboratory conditions, which are humidified atmosphere, 37 C degrees, and 5% CO2. Cell proliferation

  8. 10-GHz return-to-zero pulse source tunable in wavelength with a single- or multiwavelength output based on four-wave mixing in a newly developed highly nonlinear fiber

    DEFF Research Database (Denmark)

    Clausen, A. T.; Oxenlowe, L.; Peucheret, Christophe;

    2001-01-01

    In this letter, a novel scheme for a wavelength-tunable pulse source (WTPS) is proposed and characterized. It is based on four-wave mixing (FWM) in a newly developed highly nonlinear fiber between a return-to-zero (RZ) pulsed signal at a fixed wavelength and a continuous wave probe tunable...... the WTPS compared to the original RZ pulses is negligible....

  9. Relationship between T-wave amplitude and oxygen pulse in guinea pigs in hyperbaric helium and hydrogen.

    Science.gov (United States)

    Kayar, S R; Parker, E C; Aukhert, E O

    1998-09-01

    Diving is known to induce a change in the amplitude of the T wave (ATw) of electrocardiograms, but it is unknown whether this is linked to a change in cardiovascular performance. We analyzed ATw in guinea pigs at 10-60 atm and 25-36 degreesC, breathing 2% O2 in either helium (heliox; n = 10) or hydrogen (hydrox; n = 9) for 1 h at each pressure. Core temperature and electrocardiograms were detected by using implanted radiotelemeters. O2 consumption rate was measured by using gas chromatography. In a previous study (S. R. Kayar and E. C. Parker. J. Appl. Physiol. 82: 988-997, 1997), we analyzed the O2 pulse, i.e., the O2 consumption rate per heart beat, in the same animals. By multivariate regression analysis, we identified variables that were significant to O2 pulse: body surface area, chamber temperature, core temperature, and pressure. In this study, inclusion of ATw made a significantly better model with fewer variables. After normalizing for chamber temperature and pressure, the O2 pulse increased with increasing ATw in heliox (P = 0.001) but with decreasing ATw in hydrox (P pulse for animals breathing heliox vs. hydrox.

  10. Pulse wave myelopathy: An update of an hypothesis highlighting the similarities between syringomyelia and normal pressure hydrocephalus.

    Science.gov (United States)

    Bateman, Grant A

    2015-12-01

    Most hypotheses trying to explain the pathophysiology of idiopathic syringomyelia involve mechanisms whereby CSF is pumped against a pressure gradient, from the subarachnoid space into the cord parenchyma. On review, these theories have universally failed to explain the disease process. A few papers have suggested that the syrinx fluid may originate from the cord capillary bed itself. However, in these papers, the fluid is said to accumulate due to impaired fluid drainage out of the cord. Again, there is little evidence to substantiate this. This proffered hypothesis looks at the problem from the perspective that syringomyelia and normal pressure hydrocephalus are almost identical in their manifestations but only differ in their site of effect within the neuraxis. It is suggested that the primary trigger for syringomyelia is a reduction in the compliance of the veins draining the spinal cord. This reduces the efficiency of the pulse wave dampening, occurring within the cord parenchyma, increasing arteriolar and capillary pulse pressure. The increased capillary pulse pressure opens the blood-spinal cord barrier due to a direct effect upon the wall integrity and interstitial fluid accumulates due to an increased secretion rate. An increase in arteriolar pulse pressure increases the kinetic energy within the cord parenchyma and this disrupts the cytoarchitecture allowing the fluid to accumulate into small cystic regions in the cord. With time the cystic regions coalesce to form one large cavity which continues to increase in size due to the ongoing interstitial fluid secretion and the hyperdynamic cord vasculature.

  11. Propagation Dynamics of Nonspreading Cosine-Gauss Water-Wave Pulses.

    Science.gov (United States)

    Fu, Shenhe; Tsur, Yuval; Zhou, Jianying; Shemer, Lev; Arie, Ady

    2015-12-18

    Linear gravity water waves are highly dispersive; therefore, the spreading of initially short wave trains characterizes water surface waves, and is a universal property of a dispersive medium. Only if there is sufficient nonlinearity does this envelope admit solitary solutions which do not spread and remain in fixed forms. Here, in contrast to the nonlinear localized wave packets, we present both theoretically and experimentally a new type of linearly nondispersive water wave, having a cosine-Gauss envelope, as well as its higher-order Hermite cosine-Gauss variations. We show that these waves preserve their width despite the inherent dispersion while propagating in an 18-m wave tank, accompanied by a slowly varying carrier-envelope phase. These wave packets exhibit self-healing; i.e., they are restored after bypassing an obstacle. We further demonstrate that these nondispersive waves are robust to weakly nonlinear perturbations. In the strong nonlinear regime, symmetry breaking of these waves is observed, but their cosine-Gauss shapes are still approximately preserved during propagation. PMID:26722925

  12. Parameters effects study on pulse laser for the generation of surface acoustic waves in human skin detection applications

    Science.gov (United States)

    Li, Tingting; Fu, Xing; Dorantes-Gonzalez, Dante J.; Chen, Kun; Li, Yanning; Wu, Sen

    2015-10-01

    Laser-induced Surface Acoustic Waves (LSAWs) has been promisingly and widely used in recent years due to its rapid, high accuracy and non-contact evaluation potential of layered and thin film materials. For now, researchers have applied this technology on the characterization of materials' physical parameters, like Young's Modulus, density, and Poisson's ratio; or mechanical changes such as surface cracks and skin feature like a melanoma. While so far, little research has been done on providing practical guidelines on pulse laser parameters to best generate SAWs. In this paper finite element simulations of the thermos-elastic process based on human skin model for the generation of LSAWs were conducted to give the effects of pulse laser parameters have on the generated SAWs. And recommendations on the parameters to generate strong SAWs for detection and surface characterization without cause any damage to skin are given.

  13. Effect of isovolemic, isothermic hemodialysis on cerebral perfusion and vascular stiffness using contrast computed tomography and pulse wave velocity.

    Directory of Open Access Journals (Sweden)

    Ansgar Reising

    Full Text Available BACKGROUND: Patients undergoing hemodialysis treatment have a six-fold increased risk for stroke relative to the general population. However, the effect of hemodialysis on cerebral blood flow is poorly studied and confounding factors like blood pressure and ultrafiltration as well as temperature changes have rarely been accounted for. The aim of our study was to use state-of-the-art technology to evaluate the effect of a single dialysis session on cerebral perfusion as well as on vascular stiffness. METHODS: Chronic hemodialysis patients (7 male/3 female, mean age 58 years were recruited. Cerebral blood flow and arterial pulse wave velocity were measured before and immediately after a hemodialysis session. To exclude effects of volume changes we kept ultrafiltration to a minimum, allowing no change in body weight. Isothermic conditions were maintained by using the GENIUS single-pass batch-dialysis system with a high-flux polysulfone dialyser. Cerebral blood flow was measured by contrast-enhanced computed tomography. Pulse wave velocity was measured using the SphygmoCor (AtCor Medical, USA device by a single operator. RESULTS: This study shows for the first time that isovolemic, isothermic hemodialysis neither affected blood pressure or heart rate, nor total or regional cerebral perfusion. There was also no change in pulse wave velocity. CONCLUSIONS: Mechanisms other than the dialysis procedure itself might be causative for the high incidence of ischemic strokes in this patient population. Moreover, the sole removal of uremic toxins does not lead to short-term effects on vascular stiffness, underlying the importance of volume control in this patient population.

  14. Mechanistic investigation of doxycycline photosensitization by picosecond-pulsed and continuous wave laser irradiation of cells in culture

    Energy Technology Data Exchange (ETDEWEB)

    Shea, C.R.; Hefetz, Y.; Gillies, R.; Wimberly, J.; Dalickas, G.; Hasan, T. (Massachusetts General Hospital, Boston (USA))

    1990-04-15

    In order to elucidate the photophysical mechanisms of cellular phototoxicity sensitized by doxycycline, MGH-U1 human bladder carcinoma cells in vitro were treated with 20.7 microM doxycycline and irradiated with either a pulsed (lambda = 355 nm, pulse duration = 24 ps) or a continuous wave (lambda = 351 nm) laser. Cumulative radiant exposure and irradiance were systematically varied in experiments with both lasers. Phototoxicity was assessed by epifluorescence microscopy of unfixed cells using rhodamine 123 labeling of mitochondria. With the continuous wave source, the cumulative radiant exposure required for induction of phototoxic injury was independent of irradiance. With the 24-ps-pulsed source, a significantly lower cumulative radiant exposure was required to induce the phototoxicity when the peak irradiance was 5.8 x 10(7) or 1.3 x 10(8) watts cm-2 compared with when peak irradiance was either lower (6.0 x 10(6) watts cm-2) or higher (7.6 x 10(8) watts cm-2). The measured fluorescence lifetimes of doxycycline in buffered saline solution were longer than the laser pulse duration of 24 ps. The increased efficiency of photosensitization at the optimal peak irradiance in the ps domain appears to result from sequential multiphoton absorption involving higher excited states of the singlet manifold. At the highest irradiance studied, on the other hand, reduced efficiency of photosensitization is attributed to increased photodegradation of doxycycline from higher excited states by processes such as photoionization. A model consistent with these observations is presented along with calculations, based on simple rate equations, that fit the essentials of the proposed model.

  15. Comparative Study on the Pulse Wave Variables and Sasang Constitution in Cerebral Infarction Patients and Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Ko KiDuk

    2007-06-01

    Full Text Available This study was performed to determine whether a pulse analyzer was useful 1 to characterize the variables of pulse wave of cerebral infarction patieno (CI, compared with those of healthy subjects, as well as 2 to determine Sasang Constitution in CI and healthy subjects. 1. Calibrated in Gwan, the amount of energy(Energy, height of main peak(H1, height of aorticvalley(H2, height of aortic peak(H3, total area of pulse wave(At, and area of main peak width(Aw of the CI group were higher than those of the healthy group. 2. Calibrated in Cheek, Energy, H1, H2, H3, height of valve valley(H4, At, Aw, and main peak angle(MPA of the CI group were higher than those of the healthy group. 3. Among the healthy (subjects group, Taeumin showed the highest contact pressure(CP and height of valve peak(H5 calibrated in Chon. The main peak width divided by whole time of pulse wave(MPW/T calibrated in Gwan and Cheok, was highest in Soyangin and was lowest in Taeumin. The H3 divided by H1(H3/H1 and the time to valve valley minus the time to main peak and divided by T[(T4-T1/T] calibrated in Cheek were highest in Soyangin. The time to main peak(T1 was longest in Soumin. 4. Among the CI group, At calibrated in Chon was widest in Taeumin and was narrowest in Soumin The time to aortic peak(T3 calibrated in Cheek was longest in Soumin and was shortest in Soyangin. The time to valve peak(T5 was shortest in Soyangin. 5. There were main effects of cerebral infarction in the area of systolic period(As and area of diastolic period(Ad calibrated in Chon, Energy calibrated in Cwan, and Energy, H1, H2, H3, (H4+H5/Hl, and MPA calibrated in Cheek. 6. There were main effects of Sasang Constitution in (T4-T1/T, area of systolic period(As, and Ad calibrated in Chon. 7. The interactions between the cerebral infarction and Sasang Constitution were observed in H5/H1 , T, At, As, Ad, and MPA calibrated in Chon, H4, T4, (T4-T1/T, As, and Ad calibrated in Cwan, and 74,75, and MPW calibrated

  16. Investigation of low-temperature-grown GaAs photoconductive antennae for continuous-wave and pulsed terahertz generation

    OpenAIRE

    Loata, Gabriel C.

    2007-01-01

    The main subject of the thesis is the investigation of low-temperature-grown (LTG) GaAs-based photoconductive switches used in the generation of continuous-wave (CW) and pulsed terahertz (THz) radiation. The use of photoconductive switches based on low-temperature-grown GaAs proved to be a viable option in generating electromagnetic transients on a subpicosecond time-scale, corresponding to frequencies of ~1012 Hz (between microwave and far-infrared). The most appealing property of LTG-GaAs i...

  17. High levels of mannose-binding lectin are associated with lower pulse wave velocity in uraemic patients

    DEFF Research Database (Denmark)

    Hornum, Mads; Bay, Jakob T; Clausen, Peter;

    2014-01-01

    MBL on vascular parameters in uraemic patients. METHODS: A cohort of 98 patients with end stage renal disease (ESRD) awaiting kidney transplantation had pulse wave velocity (PWV) and augmentation index (AIX) examined by tonometry and endothelial dependent flow-mediated (FMD) and endothelial...... group with high MBL levels. No difference was seen in FMD and NID. CONCLUSIONS: High levels of MBL are associated with lower PWV and the use of antihypertensive drugs in a cohort of patients with ESRD awaiting kidney transplantation suggesting a beneficial role of high levels of MBL on arterial...

  18. Optical Force on Two-level Atoms by Few-cycle Pulsed Gaussian Laser field beyond the Rotating Wave Approximation

    OpenAIRE

    Kumar, Parvendra; Sarma, Amarendra K.

    2011-01-01

    We report a study on light force on a beam of neutral two-level atoms superimposed upon a few-cycle pulsed Gaussian laser field under both resonant and off-resonant condition. The phenomena of focusing, defocusing and steering of the neutral atoms in the laser field is analysed by solving the optical Bloch equation beyond the rotating wave approximation and the force equation self-consistently .We find that two-level atoms in an atomic beam could be focused and defocused for large, positively...

  19. Power microwave pulse generation of resonant relativistic backward wave tube with power supply based on explosive magnetocumulative generators

    International Nuclear Information System (INIS)

    High-power microwave radiation has been generated using a resonant relativistic backward wave oscillator (BWO) powered by a high voltage source comprising an inductive energy storage and an electric-explosion current switch, the results of the experiment are provided. The high voltage source and the BWO magnetic system are energy pumped by explosive magnetocumulative generators. In the experiments the setup generated 30-ns single-mode radiation pulses with a carrier frequency of 3.6 GHz at a peak power of 0.75 GW

  20. Pressure waves in liquid mercury target from pulsed heat loads and the possible way controlling their effects

    Energy Technology Data Exchange (ETDEWEB)

    Ni, L.; Skala, K. [Paul Scherrer Institute, Villingen (Switzerland)

    1996-06-01

    In ESS project liquid metals are selected as the main target for the pulsed spallation neutron source. Since the very high instantaneous energy is deposited on the heavy molten target in a very short period time, pressure waves are generated. They travel through the liquid and cause high stress in the container. Also, additional stress should be considered in the wall which is the result of direct heating of the target window. These dynamic processes were simulated with computational codes with the static response being analized first. The total resulting dynamic wall stress has been found to have exceeded the design stress for the selected container material. Adding a small amount of gas bubbles in the liquid could be a possible way to reduce the pressure waves.

  1. Dissipative Rogue Waves Generated by Chaotic Pulse Bunching in a Mode-Locked Laser

    Science.gov (United States)

    Lecaplain, C.; Grelu, Ph.; Soto-Crespo, J. M.; Akhmediev, N.

    2012-06-01

    Rare events of extremely high optical intensity are experimentally recorded at the output of a mode-locked fiber laser that operates in a strongly dissipative regime of chaotic multiple-pulse generation. The probability distribution of these intensity fluctuations, which highly depend on the cavity parameters, features a long-tailed distribution. Recorded intensity fluctuations result from the ceaseless relative motion and nonlinear interaction of pulses within a temporally localized multisoliton phase.

  2. Experimental study on the pressure and pulse wave propagation in viscoelastic vessel tubes-effects of liquid viscosity and tube stiffness.

    Science.gov (United States)

    Ikenaga, Yuki; Nishi, Shohei; Komagata, Yuka; Saito, Masashi; Lagrée, Pierre-Yves; Asada, Takaaki; Matsukawa, Mami

    2013-11-01

    A pulse wave is the displacement wave which arises because of ejection of blood from the heart and reflection at vascular bed and distal point. The investigation of pressure waves leads to understanding the propagation characteristics of a pulse wave. To investigate the pulse wave behavior, an experimental study was performed using an artificial polymer tube and viscous liquid. A polyurethane tube and glycerin solution were used to simulate a blood vessel and blood, respectively. In the case of the 40 wt% glycerin solution, which corresponds to the viscosity of ordinary blood, the attenuation coefficient of a pressure wave in the tube decreased from 4.3 to 1.6 dB/m because of the tube stiffness (Young's modulus: 60 to 200 kPa). When the viscosity of liquid increased from approximately 4 to 10 mPa·s (the range of human blood viscosity) in the stiff tube, the attenuation coefficient of the pressure wave changed from 1.6 to 3.2 dB/m. The hardening of the blood vessel caused by aging and the increase of blood viscosity caused by illness possibly have opposite effects on the intravascular pressure wave. The effect of the viscosity of a liquid on the amplitude of a pressure wave was then considered using a phantom simulating human blood vessels. As a result, in the typical range of blood viscosity, the amplitude ratio of the waves obtained by the experiments with water and glycerin solution became 1:0.83. In comparison with clinical data, this value is much smaller than that seen from blood vessel hardening. Thus, it can be concluded that the blood viscosity seldom affects the attenuation of a pulse wave.

  3. Small gas bubble experiment for mitigation of cavitation damage and pressure waves in short-pulse mercury spallation targets

    International Nuclear Information System (INIS)

    Populations of small helium gas bubbles were introduced into a flowing mercury experiment test loop to evaluate mitigation of beam-pulse induced cavitation damage and pressure waves. The test loop was developed and thoroughly tested at the Spallation Neutron Source (SNS) prior to irradiations at the Los Alamos Neutron Science Center–Weapons Neutron Research (LANSCE–WNR) facility. Twelve candidate bubblers were evaluated over a range of mercury flow and gas injection rates by use of a novel optical measurement technique that accurately assessed the generated small bubble size distributions. Final selection for irradiation testing included two variations of a swirl bubbler provided by Japan Proton Accelerator Research Complex (J-PARC) collaborators and one orifice bubbler developed at SNS. Bubble populations of interest consisted of sizes up to 150 μm in radius with achieved gas volume fractions in the 10−5–10−4 range. The nominal WNR beam pulse used for the experiment created energy deposition in the mercury comparable to SNS pulses operating at 2.5 MW. Nineteen test conditions were completed each with 100 pulses, including variations on mercury flow, gas injection and protons per pulse. The principal measure of cavitation damage mitigation was pitting damage assessment on test specimens that were manually replaced for each test condition. Damage assessment was done after radiation decay and decontamination by optical and laser profiling microscopy with damaged area fraction and maximum pit depth being the more valued results. Damage was reduced by flow alone; the best mitigation from bubble injection was to one-third that of stagnant mercury. Other data collected included surface motion tracking by three Laser Doppler Vibrometers (LDV), test loop wall dynamic strain, beam diagnostics for charge and beam profile assessment, embedded hydrophones and pressure sensors, and sound measurement by a suite of conventional and contact microphones

  4. Small Gas Bubble Experiment for Mitigation of Cavitation Damage and Pressure Waves in Short-pulse Mercury Spallation Targets

    Energy Technology Data Exchange (ETDEWEB)

    Wendel, Mark W [ORNL; Felde, David K [ORNL; Sangrey, Robert L [ORNL; Abdou, Ashraf A [ORNL; West, David L [ORNL; Shea, Thomas J [ORNL; Hasegawa, Shoichi [Japan Atomic Energy Agency (JAEA); Kogawa, Hiroyuki [Japan Atomic Energy Agency (JAEA); Naoe, Dr. Takashi [Japan Atomic Energy Agency (JAEA); Farny, Dr. Caleb H. [Boston University; Kaminsky, Andrew L [ORNL

    2014-01-01

    Populations of small helium gas bubbles were introduced into a flowing mercury experiment test loop to evaluate mitigation of beam-pulse induced cavitation damage and pressure waves. The test loop was developed and thoroughly tested at the Spallation Neutron Source (SNS) prior to irradiations at the Los Alamos Neutron Science Center - Weapons Neutron Research Center (LANSCE-WNR) facility. Twelve candidate bubblers were evaluated over a range of mercury flow and gas injection rates by use of a novel optical measurement technique that accurately assessed the generated bubble size distributions. Final selection for irradiation testing included two variations of a swirl bubbler provided by Japan Proton Accelerator Research Complex (J-PARC) collaborators and one orifice bubbler developed at SNS. Bubble populations of interest consisted of sizes up to 150 m in radius with achieved gas void fractions in the 10^-5 to 10^-4 range. The nominal WNR beam pulse used for the experiment created energy deposition in the mercury comparable to SNS pulses operating at 2.5 MW. Nineteen test conditions were completed each with 100 pulses, including variations on mercury flow, gas injection and protons per pulse. The principal measure of cavitation damage mitigation was surface damage assessment on test specimens that were manually replaced for each test condition. Damage assessment was done after radiation decay and decontamination by optical and laser profiling microscopy with damaged area fraction and maximum pit depth being the more valued results. Damage was reduced by flow alone; the best mitigation from bubble injection was between half and a quarter that of flow alone. Other data collected included surface motion tracking by three laser Doppler vibrometers (LDV), loop wall dynamic strain, beam diagnostics for charge and beam profile assessment, embedded hydrophones and pressure sensors, and sound measurement by a suite of conventional and contact microphones.

  5. Propagation of the nuclear electromagnetic pulse ground wave%核电磁脉冲地波传播规律

    Institute of Scientific and Technical Information of China (English)

    孙蓓云; 程引会; 聂鑫; 周辉

    2012-01-01

    The principle of the ground wave propagation for Electromagnetic Pulse(EMP) is presented. The propagation function of ground wave varying with the distance and frequency is developed as the ground conductivity above 0.005 S/m, and the EMP ground wave of nuclear explosion at different distances are computed. The results show that the amplitude of the propagation function is reduced with the increasing of frequency and distance, and the EMP ground wave is attenuated by ten times at a distance of 500 km from nuclear explosion location.%介绍了核电磁脉冲地波传播的理论计算方法,研究了当大地电导率大于0.005 S/m时,地波传播函数随频率及传播距离的变化规律,并计算了不同传播距离核爆电磁脉冲的地波电场.结果表明,频率越高,传播距离越远,传播函数的幅值越小;核爆电磁脉冲的传播距离为500 km时,电场的幅度会有大于一个量级的衰减.

  6. Measuring aortic pulse wave velocity using high-field cardiovascular magnetic resonance: comparison of techniques

    Directory of Open Access Journals (Sweden)

    Shaffer Jean M

    2010-05-01

    Full Text Available Abstract Background The assessment of arterial stiffness is increasingly used for evaluating patients with different cardiovascular diseases as the mechanical properties of major arteries are often altered. Aortic stiffness can be noninvasively estimated by measuring pulse wave velocity (PWV. Several methods have been proposed for measuring PWV using velocity-encoded cardiovascular magnetic resonance (CMR, including transit-time (TT, flow-area (QA, and cross-correlation (XC methods. However, assessment and comparison of these techniques at high field strength has not yet been performed. In this work, the TT, QA, and XC techniques were clinically tested at 3 Tesla and compared to each other. Methods Fifty cardiovascular patients and six volunteers were scanned to acquire the necessary images. The six volunteer scans were performed twice to test inter-scan reproducibility. Patient images were analyzed using the TT, XC, and QA methods to determine PWV. Two observers analyzed the images to determine inter-observer and intra-observer variabilities. The PWV measurements by the three methods were compared to each other to test inter-method variability. To illustrate the importance of PWV using CMR, the degree of aortic stiffness was assessed using PWV and related to LV dysfunction in five patients with diastolic heart failure patients and five matched volunteers. Results The inter-observer and intra-observer variability results showed no bias between the different techniques. The TT and XC results were more reproducible than the QA; the mean (SD inter-observer/intra-observer PWV differences were -0.12(1.3/-0.04(0.4 for TT, 0.2(1.3/0.09(0.9 for XC, and 0.6(1.6/0.2(1.4 m/s for QA methods, respectively. The correlation coefficients (r for the inter-observer/intra-observer comparisons were 0.94/0.99, 0.88/0.94, and 0.83/0.92 for the TT, XC, and QA methods, respectively. The inter-scan reproducibility results showed low variability between the repeated

  7. Noise-like pulse based on dissipative four-wave-mixing with photonic crystal fiber filled by reduced graphene oxide

    CERN Document Server

    Gao, Lei; Huang, Wei

    2014-01-01

    A noise-like pulse based on dissipative four-wave-mixing in a fiber cavity with photonic crystal fiber filled by reduced graphene oxide is proposed. Due to large evanescent field provided by 3 cm photonic crystal fiber and ultrahigh nonlinearity of reduced graphene oxide, this mixed structure provides excellent saturable absorption and high nonlinearity, which are necessary for generating four-wave-mixing (FWM). We experimentally prove that the mode-locked laser transfers its energy from center wavelength to sidebands through degenerate FWM, and new frequencies are generated via cascaded FWM among those sidebands. During this process, the frequencies located in various orders of longitudinal modes of the ring cavity are supported, and others are suppressed due to destructive interference. As the longitudinal modes of the cavity with a spacing of 6.874 MHz are partially supported, the loosely fixed phase relationship results in noise-like pulse with a coherent peak of 530 fs locating on a pedestal of 730.693 p...

  8. Measurement of Spatial Pulse Wave Velocity by Using a Clip-Type Pulsimeter Equipped with a Hall Sensor and Photoplethysmography

    Directory of Open Access Journals (Sweden)

    Sang-Suk Lee

    2013-04-01

    Full Text Available A prototype of a clip-type pulsimeter equipped with a magnetic field-sensing semiconductor Hall sensor was developed. It has a permanent magnet attached in the “Chwan” position to the center of a radial artery. The clip-type pulsimeter is composed of a hardware system measuring voltage signals. To measure spatial pulse wave velocity (SPWV, the signal from the radial artery pulsimeter and that from the photoplethysmography (PPG were simultaneously compared. The pulse wave data from a clinical test of 39 clinical participants (male:female = 25:14 with a mean age of 24.36 (±2.35 years was analyzed. The mean SPWV, which was simultaneously measured from the radial artery pulsimeter and PPG, was 0.8 m/s. We suggest the SPWV results were higher for men than women, because of the better vascularity of terminal tissue in men. The findings of this research may be useful for developing a biomedical signal storage device for a U-health-care system.

  9. One-dimensional modelling of pulse wave propagation in human airway bifurcations in space-time variables.

    Science.gov (United States)

    Clavica, Francesco; Alastruey, Jordi; Sherwin, Spencer J; Khir, Ashraf W

    2009-01-01

    Airflow in the respiratory system is complicated as it goes through various regions with different geometries and mechanical properties. Three-dimensional (3-D) simulations are typically limited to local areas of the system because of their high computational cost. On the other hand, the one-dimensional (1-D) equations of flow in compliant tubes offer a good compromise between accuracy and computational cost when a global assessment of airflow in the system is required. The aim of the current study is to apply the 1-D formulation in space and time variables to study the propagation of a pulse wave in human airways; first in a simple system composed of just one bifurcation, trachea-main bronchi, according to the symmetrical Weibel model. Then extending the system to include a further generation, the bronchi branches. Pulse waveforms carry information about the functionality and morphology of the respiratory system and the 1-D modelling, in terms of space and time variables, represents an innovative approach for respiratory response interpretation. 1-D modelling in space-time variables has been extensively applied to simulate blood pressure and flow in the cardiovascular system. This work represents the first attempt to apply this formulation to study pulse waveforms in the human bronchial tree. PMID:19965046

  10. Comparison of therapeutic effects between pulsed and continuous wave 810-nm wavelength laser irradiation for traumatic brain injury in mice.

    Directory of Open Access Journals (Sweden)

    Takahiro Ando

    Full Text Available BACKGROUND AND OBJECTIVE: Transcranial low-level laser therapy (LLLT using near-infrared light can efficiently penetrate through the scalp and skull and could allow non-invasive treatment for traumatic brain injury (TBI. In the present study, we compared the therapeutic effect using 810-nm wavelength laser light in continuous and pulsed wave modes in a mouse model of TBI. STUDY DESIGN/MATERIALS AND METHODS: TBI was induced by a controlled cortical-impact device and 4-hours post-TBI 1-group received a sham treatment and 3-groups received a single exposure to transcranial LLLT, either continuous wave or pulsed at 10-Hz or 100-Hz with a 50% duty cycle. An 810-nm Ga-Al-As diode laser delivered a spot with diameter of 1-cm onto the injured head with a power density of 50-mW/cm(2 for 12-minutes giving a fluence of 36-J/cm(2. Neurological severity score (NSS and body weight were measured up to 4 weeks. Mice were sacrificed at 2, 15 and 28 days post-TBI and the lesion size was histologically analyzed. The quantity of ATP production in the brain tissue was determined immediately after laser irradiation. We examined the role of LLLT on the psychological state of the mice at 1 day and 4 weeks after TBI using tail suspension test and forced swim test. RESULTS: The 810-nm laser pulsed at 10-Hz was the most effective judged by improvement in NSS and body weight although the other laser regimens were also effective. The brain lesion volume of mice treated with 10-Hz pulsed-laser irradiation was significantly lower than control group at 15-days and 4-weeks post-TBI. Moreover, we found an antidepressant effect of LLLT at 4-weeks as shown by forced swim and tail suspension tests. CONCLUSION: The therapeutic effect of LLLT for TBI with an 810-nm laser was more effective at 10-Hz pulse frequency than at CW and 100-Hz. This finding may provide a new insight into biological mechanisms of LLLT.

  11. Generation and Amplification of Tunable Multicolored Femtosecond Laser Pulses by Using Cascaded Four-Wave Mixing in Transparent Bulk Media

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2010-04-01

    Full Text Available We have reviewed the generation and amplification of wavelength-tunable multicolored femtosecond laser pulses using cascaded four-wave mixing (CFWM in transparent bulk media, mainly concentrating on our recent work. Theoretical analysis and calculations based on the phase-matching condition could explain well the process semi-quantitatively. The experimental studies showed: (1 as many as fifteen spectral up-shifted and two spectral down-shifted sidebands were obtained simultaneously with spectral bandwidth broader than 1.8 octaves from near ultraviolet (360 nm to near infrared (1.2 μm; (2 the obtained sidebands were spatially separated well and had extremely high beam quality with M2 factor better than 1.1; (3 the wavelengths of the generated multicolor sidebands could be conveniently tuned by changing the crossing angle or simply replacing with different media; (4 as short as 15-fs negatively chirped or nearly transform limited 20-fs multicolored femtosecond pulses were obtained when one of the two input beams was negatively chirped and the other was positively chirped; (5 the pulse energy of the sideband can reach a μJ level with power stability better than 1% RMS; (6 broadband two-dimensional (2-D multicolored arrays with more than ten periodic columns and more than ten rows were generated in a sapphire plate; (7 the obtained sidebands could be simultaneously spectra broadened and power amplified in another bulk medium by using cross-phase modulation (XPM in conjunction with four-wave optical parametric amplification (FOPA. The characterization showed that this is interesting and the CFWM sidebands generated by this novel method have good enough qualities in terms of power stability, beam quality, and temporal features suited to various experiments such as ultrafast multicolor time-resolved spectroscopy and multicolor-excitation nonlinear microscopy.

  12. Suppression of parasitic noise by strong Langmuir wave damping in quasitransient regimes of backward Raman amplification of intense laser pulses in plasmas.

    Science.gov (United States)

    Malkin, Vladimir; Fisch, Nathaniel

    2009-11-01

    Currently built powerful soft x-ray sources may be able to access intensities needed for backward Raman amplification (BRA) of x-ray pulses in plasmas. However, high plasma densities, needed to provide enough coupling between the pump and seed x-ray pulsed, cause strong damping of the Langmuir wave that mediates energy transfer from the pump to the seed pulse. Such damping could reduce the coupling, thus making efficient BRA impossible. This work shows that efficient BRA can survive despite the Langmuir wave damping significantly exceeding the linear BRA growth rate. Moreover, the strong Langmuir wave damping can suppress deleterious instabilities of BRA seeded by the thermal noise. This shows that it may be feasible to observe x-ray BRA for the first time soon.

  13. Absolute frequency synthesis of pulsed coherent light waves through phase-modulation active optical feedback.

    Science.gov (United States)

    Shimizu, K; Horiguchi, T; Koyamada, Y

    1996-11-15

    A novel method for the broadband absolute frequency synthesis of pulsed coherent lightwaves is demonstrated. It is based on pulse recirculation around an active optical feedback ring containing a delay-line fiber, an external phase modulator, an acousto-optic frequency shifter (AOFS), and a high-finesse Fabry-Perot étalon. The modulation frequency F(M) and the frequency shift F(AO) that are due to AOFS are designed so that their sum or difference equals the free-spectral range of the étalon and F(AO) is set at larger than the half-width at full maximum of its resonant peaks. If one of the peak frequencies is tuned to the frequency of the initial pulse, the frequency of the recirculating pulse jumps to the next peak for each round trip. In the experiment the absolute frequency is synthesized over a frequency span of 700 GHz around the initial stabilized frequency of the master laser.

  14. Continuous-wave vs. pulsed infrared laser stimulation of the rat prostate cavernous nerves

    Science.gov (United States)

    Tozburun, Serhat; Cilip, Christopher M.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

    2011-03-01

    Optical nerve stimulation has recently been developed as an alternative to electrical nerve stimulation. However, recent studies have focused primarily on pulsed delivery of the laser radiation and at relatively low pulse rates. The objective of this study is to demonstrate faster optical stimulation of the prostate cavernous nerves using continuouswave (CW) infrared laser radiation, for potential diagnostic applications. A Thulium fiber laser (λ = 1870 nm) was used for non-contact optical stimulation of the rat prostate cavernous nerves, in vivo. Optical nerve stimulation, as measured by an intracavernous pressure (ICP) response in the penis, was achieved with the laser operating in either CW mode, or with a 5-ms pulse duration at 10, 20, 30, 40, 50, and 100 Hz. Successful optical stimulation was observed to be primarily dependent on a threshold nerve temperature (42-45 °C), not an incident fluence, as previously reported. CW optical nerve stimulation provides a significantly faster ICP response time using a laser with lower power output than pulsed stimulation. CW optical nerve stimulation may therefore represent an alternative mode of stimulation for intra-operative diagnostic applications where a rapid response is critical, such as identification of the cavernous nerves during prostate cancer surgery.

  15. Long-range non-contact imaging photoplethysmography: cardiac pulse wave sensing at a distance

    Science.gov (United States)

    Blackford, Ethan B.; Estepp, Justin R.; Piasecki, Alyssa M.; Bowers, Margaret A.; Klosterman, Samantha L.

    2016-03-01

    Non-contact, imaging photoplethysmography uses photo-optical sensors to measure variations in light absorption, caused by blood volume pulsations, to assess cardiopulmonary parameters including pulse rate, pulse rate variability, and respiration rate. Recently, researchers have studied the applications and methodology of imaging photoplethysmography. Basic research has examined some of the variables affecting data quality and accuracy of imaging photoplethysmography including signal processing, imager parameters (e.g. frame rate and resolution), lighting conditions, subject motion, and subject skin tone. This technology may be beneficial for long term or continuous monitoring where contact measurements may be harmful (e.g. skin sensitivities) or where imperceptible or unobtrusive measurements are desirable. Using previously validated signal processing methods, we examined the effects of imager-to-subject distance on one-minute, windowed estimates of pulse rate. High-resolution video of 22, stationary participants was collected using an enthusiast-grade, mirrorless, digital camera equipped with a fully-manual, super-telephoto lens at distances of 25, 50, and 100 meters with simultaneous contact measurements of electrocardiography, and fingertip photoplethysmography. By comparison, previous studies have usually been conducted with imager-to-subject distances of up to only a few meters. Mean absolute error for one-minute, windowed, pulse rate estimates (compared to those derived from gold-standard electrocardiography) were 2.0, 4.1, and 10.9 beats per minute at distances of 25, 50, and 100 meters, respectively. Long-range imaging presents several unique challenges among which include decreased, observed light reflectance and smaller regions of interest. Nevertheless, these results demonstrate that accurate pulse rate measurements can be obtained from over long imager-to-participant distances given these constraints.

  16. Thermally induced transparency for short spin wave pulses in yttrium iron garnet (YIG) films

    Science.gov (United States)

    Ordonez Romero, Cesar Leonardo; Kolokoltsev, Oleg; Gomez Arista, Ivan; Qureshi, Naser; Monsiváis Galindo, Guillermo; Vargas Hernández, Hesiquio

    2014-03-01

    The compensation of spin wave propagation losses plays a very important role in the development of novel magnonic devices. Up to now, however, most of the known amplification methods present relative narrow frequency bandwidths due to their resonant nature. In this work, we present compensation of the propagation losses or pseudo-amplification of travelling spin waves by tailoring the bias magnetic field profile. The thermally-induced non-uniform profile of the magnetization introduced on an Yttrium Iron Garnet (YIG) thin film by a localized spot of a cw argon-ion laser creates the conditions to observe the complete compensation of the spin wave propagation losses. The spin wave evolution was mapped with a time and spaced resolved inductive magneto-dynamic prove system. The experiment was carried out using a uniform sample of single-crystal YIG film grown on a gallium-gadolinium garnet (GGG) substrate. The 2mm-wide, 20mm-long and 6microns-thick YIG strip was saturated with an external magnetic field enabling the set up for the propagation of magneto-static surface waves. This work was supported by the UNAM-DGAPA-PAPIIT IA100413.

  17. Bulk waves excited by a laser line pulse in a two-layered cylinder

    Science.gov (United States)

    Pan, Y.; Chigarev, N.; Audoin, B.

    2010-01-01

    The acoustic displacements excited by a laser line source under either the ablation or thermoelastic regime are calculated for a two-layered cylinder made of homogeneous and isotropic materials. Two samples made by welding tin in two different copper tubes are considered. Experimental displacements are observed by the laser ultrasonic technique, and corresponding theoretical waveforms are calculated. Good agreement is found in the arrival time, shape, and relative amplitude of various longitudinal and shear bulk waves propagating in the two-layered cylinders, and the waves reflected by the interface are further identified by the ray trajectory analysis. The longitudinal wave reflected at the interface may be used for the nondestructive evaluation of the interface quality.

  18. Nonlinear self-focus of pulsed-wave beams in Kerr media

    Energy Technology Data Exchange (ETDEWEB)

    Judkins, J.B.

    1992-12-31

    A modified finite-difference time-domain method for solving Maxwell`s equations in nonlinear media is presented. This method allows for a finite response time to be incorporated in the medium, physically creating dispersion and absorption mechanisms. The technique models electromagnetic fields in two space dimensions and time and encompasses both the TE{sub z} and TM{sub z} set of decoupled field equations. Aspects of an ultra-short pulsed Gaussian beam are studied in a variety of linear and nonlinear environments to demonstrate that the methods developed here can be used efficaciously in the modeling of pulses in complex problem space geometries even when nonlinearities are present.

  19. Emission of terahertz waves in the interaction of a laser pulse with clusters

    Science.gov (United States)

    Frolov, A. A.

    2016-07-01

    A theory of generation of terahertz radiation in the interaction of a femtosecond laser pulse with a spherical cluster is developed for the case in which the density of free electrons in the cluster plasma exceeds the critical value. The spectral, angular, and energy characteristics of the emitted terahertz radiation are investigated, as well as its spatiotemporal structure. It is shown that the directional pattern of radiation has a quadrupole structure and that the emission spectrum has a broad maximum at a frequency nearly equal to the reciprocal of the laser pulse duration. It is found that the total radiated energy depends strongly on the cluster size. Analysis of the spatiotemporal profile of the terahertz signal shows that it has a femtosecond duration and contains only two oscillation cycles.

  20. Dynamics of atomic spin-orbit-state wave packets produced by short-pulse laser photodetachment

    CERN Document Server

    Law, S M K

    2016-01-01

    We analyse the experiment by Hultgren et al. [Phys. Rev. A {\\bf 87}, 031404 (2013)] on orbital alignment and quantum beats in coherently excited atomic fine-structure manifolds produced by short-pulse laser photodetachment of C$^-$, Si$^-$ and Ge$^-$ negative ions, and derive a formula that describes the beats. Analysis of the experimental data enables us to extract the non-coherent background contribution for each species, and indicates the need for a full density matrix treatment of the problem.

  1. Ionospheric cusp flows pulsed by solar wind Alfvén waves

    OpenAIRE

    Prikryl, P.; Provan, G.; K. A. McWilliams; Yeoman, T. K.

    2002-01-01

    Pulsed ionospheric flows (PIFs) in the cusp foot-print have been observed by the SuperDARN radars with periods between a few minutes and several tens of minutes. PIFs are believed to be a consequence of the interplanetary magnetic field (IMF) reconnection with the magnetospheric magnetic field on the dayside magnetopause, ionospheric signatures of flux transfer events (FTEs). The quasiperiodic PIFs are correlated with Alfvénic fluctuations observed in the upstream solar wind. It is con...

  2. Solitary pulses and periodic waves in the parametrically driven complex Ginzburg-Landau equation

    OpenAIRE

    Sakaguchi, Hidetsugu; Malomed, Boris

    2003-01-01

    A one-dimensional model of a dispersive medium with intrinsic loss, compensated by a parametric drive, is proposed. It is a combination of the well-known parametrically driven nonlinear Schr\\"{o}dinger (NLS) and complex cubic Ginzburg-Landau equations, and has various physical applications (in particular, to optical systems). For the case when the zero background is stable, we elaborate an analytical approximation for solitary-pulse (SP) states. The analytical results are found to be in good ...

  3. Investigation of a diode-pumped intracavity optical parametric oscillator in pulsed and continuous wave operation

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Skettrup, Torben; Balle-Petersen, O.;

    2001-01-01

    Summary form only given. CW and pulsed compact tunable laser sources in the infrared have widespread scientific, medical and industrial applications. Such a laser source can be obtained by use of a diode-pumped intracavity optical parametric oscillator (IOPO). We report on a IOPO based on a Yb:YA...... lens to generate a beam waist in the PPLN crystal, a dichroic mirror to separate the laser and signal fields and two end mirrors...

  4. Energetic mid-IR femtosecond pulse generation by self-defocusing soliton-induced dispersive waves in a bulk quadratic nonlinear crystal

    DEFF Research Database (Denmark)

    Zhou, Binbin; Guo, Hairun; Bache, Morten

    2015-01-01

    and without critical phase-matching requirements. Pumping a bulk quadratic nonlinear crystal (unpoled LiNbO3 cut for noncritical phase-mismatched interaction) with sub-mJ near-IR 50-fs pulses, tunable and broadband (∼ 1,000 cm−1) mid-IR pulses around 3.0 μm are generated with excellent spatio-temporal pulse...... quality, having up to 10.5 μJ energy (6.3% conversion). The mid-IR pulses are dispersive waves phase-matched to near-IR self-defocusing solitons created by the induced self-defocusing cascaded nonlinearity. This process is filament-free and the input pulse energy can therefore be scaled arbitrarily...

  5. Reconstruction of wave features in wind-driven water film flow using ultrasonic pulse-echo technique

    Science.gov (United States)

    Liu, Yang; Bond, Leonard J.; Hu, Hui

    2016-02-01

    Aircraft operating in weather conditions that can cause glaze icing face the risk of performance degradation, and increased costs in de-icing procedures. The water run-back in glaze ice accretion can redistribute the impinging water mass and disturb the local flow field, and hence, affect the morphology of ice accretion. Understanding the mechanism of the surface water film transportation is important and challenging, and critical to enabling improvement in the modeling of glaze icing. In this study, an ultrasonic multi-transducer (sparse array) pulse-echo (UMTPE) technique was developed to measure thin film thickness fluctuation. The technical basis for UMTPE technique and the factors that influence the measurements are described. The UMTPE technique was configured to provide time-resolved multi-point thickness measurements. Quantitative measurements of the wind-driven water film flow are achieved by using the UMTPE technique. Point-wise thickness variations can be obtained from each individual channel in the UMTPE system. Span-wise thickness profile can be derived by interpolating the point-wise measurements. The span-wise thickness profiles can be expanded in time domain, which shows the overall flow structures. The velocity of surface wave features is derived by performing a cross-correlation of the upstream and downstream thickness variations, which is then used to transform the temporal thickness fluctuation into the spatial wave structures. The time-resolved spatial flow structures are obtained by applying the transformation along time axis, which present more details of wave structures and the evolution of wave features.

  6. Bramwell-Hill modeling for local aortic pulse wave velocity estimation: a validation study with velocity-encoded cardiovascular magnetic resonance and invasive pressure assessment

    OpenAIRE

    Westenberg Jos JM; van Poelgeest Eveline P; Steendijk Paul; Grotenhuis Heynric B; Jukema JW; de Roos Albert

    2012-01-01

    Abstract Background The Bramwell-Hill model describes the relation between vascular wall stiffness expressed in aortic distensibility and the pulse wave velocity (PWV), which is the propagation speed of the systolic pressure wave through the aorta. The main objective of this study was to test the validity of this model locally in the aorta by using PWV-assessments based on in-plane velocity-encoded cardiovascular magnetic resonance (CMR), with invasive pressure measurements serving as the gol...

  7. The test ability of an adaptive pulse wave for ADC testing

    NARCIS (Netherlands)

    Sheng, Xiaoqin; Kerkhoff, Hans G.

    2010-01-01

    In the conventional ADC production test method, a high-quality analogue sine wave is applied to the Analogue-to-Digital Converter (ADC), which is expensive to generate. Nowadays, an increasing number of ADCs are integrated into a system-on-chip (SoC) platform design, which usually contains a digital

  8. 太赫兹波脉冲成像和连续波成像技术研究%Investigation of Terahertz Continuous Wave Imaging and Pulse Wave Imaging

    Institute of Scientific and Technical Information of China (English)

    陈素果; 侯磊; 楼骁; 董陈岗; 施卫

    2013-01-01

    介绍了太赫兹(THz)连续波成像和脉冲波成像的原理,报道了自主研制的连续太赫兹波及脉冲太赫兹波成像系统:太赫兹连续波成像方面,分别使用研制的辉光放电探测器(GDD)和商业化的肖特基二极管对同一物体成像,结果表明GDD是一种成本低、成像效果好的室温太赫兹波探 测器;在太赫兹脉冲波成像方面,利用研制的SI-GaAs光电导天线作为太赫兹源,对金属环成像,分析了频率对的振幅图像和相位图像的影响.%In this paper,the principle of THz continuous wave imaging and THz pulse wave imaging are introduced.THz continuous wave and THz pulse wave imaging system developed self-independently are reported.In continuous wave imaging,the glow discharge detector (GDD) developed by our group and a commercial Schottky diodes are used as the detectors for THz continuous wave imaging,and the results indicate that GDD is a potential THz continuous wave room-temperature detector with low cost and high imaging quality.In THz pulse imaging,the SI-GaAs photoconductive antenna developed by our group is used as a pulse THz source to carry out the pulse imaging of a metal ring.The THz amplitude imaging and phase imaging at different frequencies are analyzed.

  9. Silencing by blasting: combination of laser pulse induced stress waves and magnetophoresis for siRNA delivery

    Science.gov (United States)

    Babincová, M.; Babincová, N.; Durdík, S.; Bergemann, C.; Sourivong, P.

    2016-06-01

    A new method is developed for efficient delivery of short interference RNA into cells using combination of magnetophoresis for pre-concentration of siRNA-magnetic nanoparticle complex on the surface of cells with subsequent nanosecond laser pulse generating stress waves in transfection chamber, which is able to permeabilize cell membrane for the facilitated delivery of siRNA into the cell interior. As has been shown using siRNA inducing cell apoptosis, combination of these two physical factors increased the efficiency of three different human carcinoma cells transfection to 93%, 89%, and 84%, for HeLa (cervical carcinoma), MCF-7 (breast carcinoma), and UCI-107 (ovarian carcinoma) cells, respectively. This new physical method of siRNA delivery may have therefore far reaching applications in biotechnology and functional genomics.

  10. Gain-assisted superluminal microwave pulse propagation via four-wave mixing in superconducting phase quantum circuits

    CERN Document Server

    Sabegh, Z Amini; Maleki, M A; Mahmoudi, M

    2015-01-01

    We study the propagation and amplification of a microwave field in a four-level cascade quantum system which is realized in a superconducting phase quantum circuit. It is shown that by increasing the microwave pump tones feeding the system, the normal dispersion switches to the anomalous and the gain-assisted superluminal microwave propagation is obtained in this system. Moreover, it is demonstrated that the stimulated microwave field is generated via four-wave mixing without any inversion population in the energy levels of the system (amplification without inversion) and the group velocity of the generated pulse can be controlled by the external oscillating magnetic fluxes. We also show that in some special set of parameters, the absorption-free superluminal generated microwave propagation is obtained in superconducting phase quantum circuit system.

  11. The influence of fluid properties and pulse amplitude on bubble dynamics in the field of a shock wave lithotripter.

    Science.gov (United States)

    Choi, M J; Coleman, A J; Saunders, J E

    1993-11-01

    This study concerns the radial dynamics of a bubble driven by pulsed ultrasound of the type generated during extracorporeal shock wave lithotripsy. In particular, a numerical model has been used to examine the sensitivity of the bubble oscillations to changes in both the amplitude of the driving field and the physical conditions of the fluid surrounding the bubble: viscosity, surface tension, temperature and gas content. It is shown that, at high negative pressures (p- = 10 MPa) as in lithotripsy, the timing and amplitude of bubble collapses have a considerably reduced sensitivity to the initial bubble size and all fluid parameters, except gas content, compared with those expected in lower-amplitude fields (p- = 0.2 MPa). This study indicates that, in the lithotripsy fields, the differences in the viscosity, surface tension and temperature of body fluids and the initial bubble size will have little effect on bubble dynamics compared with those expected in water.

  12. Anodic oxidation of etodolac and its linear sweep, square wave and differential pulse voltammetric determination in pharmaceuticals

    Directory of Open Access Journals (Sweden)

    B Yilmaz

    2015-01-01

    The well-defined oxidation peak was observed at 1.03 V. The calibration curves were linear for etodolac at the concentration range of 2.5-50 µg/ml for linear sweep, square wave and differential pulse voltammetry methods, respectively. Intra- and inter-day precision values for etodolac were less than 4.69, and accuracy (relative error was better than 2.00%. The mean recovery of etodolac was 100.6% for pharmaceutical preparations. No interference was found from three tablet excipients at the selected assay conditions. Developed methods in this study are accurate, precise and can be easily applied to Etol, Tadolak and Etodin tablets as pharmaceutical preparation.

  13. Dynamics of shock waves and cavitation bubbles in bilinear elastic-plastic media, and the implications to short-pulsed laser surgery

    Science.gov (United States)

    Brujan, E.-A.

    2005-01-01

    The dynamics of shock waves and cavitation bubbles generated by short laser pulses in water and elastic-plastic media were investigated theoretically in order to get a better understanding of their role in short-pulsed laser surgery. Numerical simulations were performed using a spherical model of bubble dynamics which include the elastic-plastic behaviour of the medium surrounding the bubble, compressibility, viscosity, density and surface tension. Breakdown in water produces a monopolar acoustic signal characterized by a compressive wave. Breakdown in an elastic-plastic medium produces a bipolar acoustic signal, with a leading positive compression wave and a trailing negative tensile wave. The calculations revealed that consideration of the tissue elasticity is essential to describe the bipolar shape of the shock wave emitted during optical breakdown. The elastic-plastic response of the medium surrounding the bubble leads to a significant decrease of the maximum size of the cavitation bubble and pressure amplitude of the shock wave emitted during bubble collapse, and shortening of the oscillation period of the bubble. The results are discussed with respect to collateral damage in short-pulsed laser surgery.

  14. Hemodynamics in the portal vein evaluated by pulse wave Doppler ultrasonography in patients with chronic hepatitis C treated with interferon

    Institute of Scientific and Technical Information of China (English)

    Shigeo Nakanishi; Katsuya Shiraki; Kouji Yamamoto; Mutsumi Koyama; Noboru Kimura; Takeshi Nakano

    2005-01-01

    AIM: To employ pulse wave Doppler ultrasonography to evaluate the changes in portal blood flow velocity in patients with chronic hepatitis C (CHC) receiving interferon (IFN)treatment.METHODS: The subjects in this study were 14 patients (13 men and 1 woman) with CHC who received IFN treatment. Portal blood flow velocity was measured in the vessels at the porta hepatis at four time points: before IFN administration (pre-IFN), 2 wk after the start of administration (wk 2), 24 wk after the start of administration (wk 24, i.e.,the end of IFN administration), and 24 wk after the end of administration (wk 48).RESULTS: The patients with CHC in whom IFN treatment resulted in complete elimination or effective elimination of viruses showed a significant increase in portal blood flow velocity at the end of IFN treatment compared with that before IFN treatment. In contrast, when IFN was ineffective, no significant increase in portal bloocl flow velocity was observed at wk 24 or 48 compared with the pre-IFN value. In addition,the patients with CHC in whom IFN was ineffective showed significantly lower portal blood flow velocity values than control subjects at all measurement time points.CONCLUSION: Pulse wave Doppler ultrasonography is a noninvasive and easily performed method for evaluating the effects of IFN treatment in patients with CHC. This technique is useful for measuring portal blood flow velocity before and 24 wk after IFN administration in order to evaluate the changes over time, thus assessing the effectiveness of IFN treatment.

  15. Normal values of aortic dimensions, distensibility, and pulse wave velocity in children and young adults: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Voges Inga

    2012-11-01

    Full Text Available Abstract Background Aortic enlargement and impaired bioelasticity are of interest in several cardiac and non-cardiac diseases as they can lead to cardiovascular complications. Cardiovascular magnetic resonance (CMR is increasingly accepted as a noninvasive tool in cardiovascular evaluation. Assessment of aortic anatomy and bioelasticity, namely aortic distensibility and pulse wave velocity (PWV, by CMR is accurate and reproducible and could help to identify anatomical and bioelastic abnormalities of the aorta. However, normal CMR values for healthy children and young adults are lacking. Methods Seventy-one heart-healthy subjects (age 16.4 ± 7.6 years, range 2.3 - 28.3 years were examined using a 3.0 Tesla CMR scanner. Aortic cross-sectional areas and aortic distensibility were measured at four positions of the ascending and descending thoracic aorta. PWV was assessed from aortic blood flow velocity measurements in a aortic segment between the ascending aorta and the proximal descending aorta. The Lambda-Mu-Sigma (LMS method was used to obtain percentile curves for aortic cross-sectional areas, aortic distensibility and PWV according to age. Results Aortic areas, PWV and aortic distensibility (aortic cross-sectional areas: r = 0.8 to 0.9, p  Conclusions This study provides percentile curves for cross-sectional areas, distensibility and pulse wave velocity of the thoracic aorta in children and young adolescents between their 3rd and 29th year of life. These data may serve as a reference for the detection of pathological changes of the aorta in cardiovascular disease.

  16. Electroanalytical characteristics of piribedil and its differential pulse and square wave voltammetric determination in pharmaceuticals and human serum.

    Science.gov (United States)

    Uslu, Bengi; Ozkan, Sibel A

    2003-03-10

    The electrochemical oxidative behavior of piribedil (PR) was described. It was investigated by cyclic, linear sweep, differential pulse (DPV) and square wave (SWV) voltammetric techniques. The redox behavior of PR was found irreversible. Different parameters were tested to optimize the conditions for the determination of PR. The dependence of intensities of currents and potential on pH, concentration, scan rate, nature of the buffer was investigated. Two sensitive methods for the measurement of PR were described. For analytical purposes, a very well resolved diffusion controlled voltammetric peak was obtained in 0.1 M H(2)SO(4) and pH 5.7 acetate buffer. The determination peaks are obtained at 1.27 and 0.95 V for differential pulse and 1.29 and 0.97 V for SWV in 0.1 M H(2)SO(4) and pH 5.7 acetate buffer, respectively. The linear response was obtained in the ranges of 2 x 10(-6)-1 x 10(-3) M in 0.1 M H(2)SO(4) and 2 x 10(-6)-8 x 10(-4) M in pH 5.7 acetate buffer for both techniques. The proposed techniques were successfully applied to the determination of PR in tablet dosage forms and human serum. Excipients did not interfere in the determination. The necessary statistical validation reveals that the proposed methods are free from significant systematic errors.

  17. Performance of a reflectometer at continuous wave and pulsed neutron sources

    International Nuclear Information System (INIS)

    The Monte-Carlo simulations presented here involve simulations of reflectivity measurements of one sample using a reflectometer of traditional geometry at different neutron sources. The same reflectometer was used in all simulations. Only the characteristics of the neutron source, and the technique used to measure neutron wavelength were changed. In the case of the CW simulation, a monochromating crystal was used to select a nearly monochromatic beam (MB) from the neutron spectrum. In the simulations of the pulse sources, the time needed to traverse a fixed distance was measured, from which neutron wavelength is deduced

  18. Development of a shock wave adhesion test for composite bonds by laser pulsed and mechanical impacts

    Science.gov (United States)

    Ecault, Romain; Boustie, Michel; Touchard, Fabienne; Arrigoni, Michel; Berthe, Laurent; CNRS Collaboration

    2013-06-01

    Evaluating the bonding quality of composite material is becoming one of the main challenges faced by aeronautic industries. This work aims the development of a technique using shock wave, which would enable to quantify the bonding mechanical quality. Laser shock experiments were carried out. This technique enables high tensile stress generation in the thickness of composite bond without any mechanical contact. The resulting damage has been quantified using different method such as confocal microscopy, ultrasound and cross section observation. The discrimination between a correct bond and a weak bond was possible thanks to these experiments. Nevertheless, laser sources are not well adapted for optimization of such a test since it has often fixed parameters. That is why mechanical impacts bonded composites were also performed in this work. By changing the thickness of aluminum projectiles, the tensile stresses generated by the shock wave propagation were moved toward the composite/bond interface. The observations made prove that the optimization of the technique is possible. The key parameters for the development of a bonding test using shock wave have been identified.

  19. Development of a shock wave adhesion test for composite bonds by pulsed laser and mechanical impacts

    Science.gov (United States)

    Ecault, R.; Boustie, M.; Touchard, F.; Arrigoni, M.; Berthe, L.

    2014-05-01

    Evaluating the bonding quality of composite material is becoming one of the main challenges faced by aeronautic industries. This work aims to the development of a technique using shock wave, which would enable to quantify the bonding mechanical quality. Laser shock experiments were carried out. This technique enables high tensile stress generation in the thickness of composite bonds. The resulting damage has been quantified using different methods such as confocal microscopy, ultrasound and cross section observation. The discrimination between a correct bond and a weak bond was possible thanks to these experiments. Nevertheless, laser sources are not well adapted for optimization of such a test because of often fixed settings. That is why mechanical impacts on bonded composites were also performed in this work. By changing the thickness of aluminum projectiles, the generated tensile stresses by the shock wave propagation were moved toward the composite/bond interface. The made observations prove that the technique optimization is possible. The key parameters for the development of a bonding test using shock waves have been identified.

  20. Compliance of the normal-sized aorta in adolescents with Marfan syndrome: comparison of MR measurements of aortic distensibility and pulse wave velocity

    International Nuclear Information System (INIS)

    Purpose: To compare the aortic compliance of the normal-sized aorta of adolescents with Marfan syndrome and healthy controls using MR measurements of the aortic distensibility and pulse wave velocity. Materials and Methods: Fourteen patients (median age: 15 [9-21] years) and 11 healthy subjects (23 [12-32] years) were examined at 1.5 T. The MR protocol included 2D steady-state free precession (SSFP)-CINE MRI of the aortic distensibility and PC-MRI of the pulse wave velocity. All measurements were positioned perpendicular to the descending aorta at the level of the diaphragm for assessing the changes in the aortic cross-sectional areas and additionally above and below this plane for assessing the pulse wave velocity. In addition contrast-enhanced 3D-MR angiography was performed in adolescents with Marfan syndrome to exclude morphologic changes and to prove normal-sized aorta. Results: Compared with control subjects, adolescents with Marfan syndrome had significantly decreased distensibility and significantly increased pulse wave velocity (χ2-test, p = 0.0002) using an age-related non-linear regression analysis. The related aortic compliance was significantly decreased (χ2-test, p = 0.0002). There was a good correlation between the two methods (r = 0.86). A low intraobserver variability was found for both methods (≤ 2 %). (orig.)

  1. Spectral pulsed-wave tissue Doppler imaging lateral-to-septal delay fails to predict clinical or echocardiographic outcome after cardiac resynchronization therapy

    NARCIS (Netherlands)

    O.I.I. Soliman (Osama Ibrahim Ibrahim); D.A.M.J. Theuns (Dominic); M.L. Geleijnse (Marcel); A. Nemes (Attila); K. Caliskan (Kadir); W.B. Vletter (Wim); L.J.L.M. Jordaens (Luc); F.J. ten Cate (Folkert)

    2007-01-01

    textabstractAims: The current study sought to assess if pre-implantation lateral-to-septal delay (LSD) ≥60 ms assessed by spectral pulsed-wave myocardial tissue Doppler imaging (PW-TDI) could predict successful long-term outcome after cardiac resynchronization therapy (CRT). Methods and results Sixt

  2. Pulsed-wave tissue Doppler and color tissue Doppler echocardiography: calibration with M-mode, agreement, and reproducibility in a clinical setting

    DEFF Research Database (Denmark)

    Olsen, Niels Thue; Jons, Christian; Fritz-Hansen, Thomas;

    2009-01-01

    BACKGROUND: Myocardial velocities can be measured with both pulsed-wave tissue Doppler (PWTD) and color tissue Doppler (CTD) echocardiography. We aimed to (A) to explore which of the two methods better approximates true tissue motion and (B) to examine the agreement and the reproducibility of the...

  3. Determinants of pulse wave velocity in healthy people and in the presence of cardiovascular risk factors: 'establishing normal and reference values'

    DEFF Research Database (Denmark)

    Hansen, Tine Willum

    2010-01-01

    Carotid-femoral pulse wave velocity (PWV), a direct measure of aortic stiffness, has become increasingly important for total cardiovascular (CV) risk estimation. Its application as a routine tool for clinical patient evaluation has been hampered by the absence of reference values. The aim...... of the present study is to establish reference and normal values for PWV based on a large European population....

  4. Parametric interference effect in nonresonant spontaneous bremsstrahlung of an electron in the field of a nucleus and two pulsed laser waves

    Science.gov (United States)

    Lebed', A. A.; Padusenko, E. A.; Roshchupkin, S. P.; Dubov, V. V.

    2016-07-01

    Nonresonant spontaneous bremsstrahlung of an electron scattered by a nucleus in the field of two moderately strong pulsed waves is studied theoretically. The process is studied in detail within the interference kinematic region. This region is determined by scattering of particles in the same plane at predetermined angles, at which stimulated absorption and emission of photons of external pulsed waves by an electron occur in a correlated manner. It is shown that the probability of the partial process with correlated emission (absorption) by an electron of the equal number of photons of the both waves is of an order of the magnitude greater than the corresponding probability in any other scattering kinematics. The cross section of spontaneous bremsstrahlung in two pulsed waves may be two times greater than the cross section of a free-field process after summation over all stimulated processes of correlated emission and absorption. Obtained results may be experimentally verified, for example, by scientific facilities at sources of pulsed laser radiation (SLAC, FAIR, ELI, XCELS).

  5. Acute elevation of plasma non-esterified fatty acids increases pulse wave velocity and induces peripheral vasodilation in humans in vivo

    NARCIS (Netherlands)

    Riksen, Niels P.; Bosselaar, Marlies; Bakker, Stephan J. L.; Heine, Robert J.; Rongen, Gerard A.; Tack, Cees J.; Smits, Paul

    2007-01-01

    Plasma NEFA (non-esterified fatty acid) concentrations are elevated in patients with obesity. In the present study we first aimed to provide an integral haemodynamic profile of elevated plasma NEFAs by the simultaneous assessment of blood pressure, pulse wave velocity, FBF (forearm blood flow) and s

  6. Reference values of central blood pressure and pulse wave velocity in relation with 24 hours ambulatory blood pressure monitoring in Belgian healthy young subjects

    OpenAIRE

    Saint-Remy, Annie; Krzesinski, Jean-Marie

    2010-01-01

    The present study aimed to define reference values of central blood pressure (cBP) and Pulse Wave Velocity (PWV) together with 24H ABPM in healthy normotensive young adults before starring a follow-up of their CV profile modifications over time. Peer reviewed

  7. Reference values of central blood pressure and pulse wave velocity in relations with 24 hours ambulatory blood pressure monitoring in Belgian normotensive young subjects

    OpenAIRE

    Saint-Remy, Annie; Krzesinski, Jean-Marie

    2010-01-01

    The present study aimed to define reference values of central blood pressure (cBP) and Pulse Wave Velocity (PWV) together with 24H APPM in healththy normotensive young adults before starting a follow-up of their CV profile modifications over time. Peer reviewed

  8. Coupled-mode theory for electromagnetic pulse propagation in dispersive media undergoing a spatiotemporal perturbation: Exact derivation, numerical validation, and peculiar wave mixing

    Science.gov (United States)

    Sivan, Y.; Rozenberg, S.; Halstuch, A.

    2016-04-01

    We present an extension of the canonical coupled-mode theory of electromagnetic waves to the case of pulses and spatiotemporal perturbations in complex media. Unlike previous attempts to derive such a model, our approach involves no approximation, and it does not impose any restriction on the spatiotemporal profile. Moreover, the effect of modal dispersion on mode evolution and on the coupling to other modes is fully taken into account. Thus, our approach can yield any required accuracy by retaining as many terms in the expansion as needed. It also avoids various artifacts of previous derivations by introducing the correct form of the solution. We then validate the coupled-mode equations with exact numerical simulations, and we demonstrate the wide range of possibilities enabled by spatiotemporal perturbations of pulses, including pulse shortening or broadening or more complex shaping. Our formulation is valid across the electromagnetic spectrum, and it can be applied directly also to other wave systems.

  9. Bulk waves excited by a laser line pulse in a bi-layer cylinder

    Science.gov (United States)

    Pan, Y.; Chigarev, N.; Audoin, B.

    2010-03-01

    In this paper, the transient displacement excited by a laser line source is calculated for a bi-layer cylinder made of homogeneous and isotropic materials. A sample made by welding tin in a copper tube and a sample of cooper rod are considered. Experimental displacements are observed by the laser ultrasonic technique, and corresponding theoretical waveforms are calculated. Good agreement is found in the arrival time, shape and relative amplitude of various longitudinal and shear bulk waves propagating through the sample or reflected by the interface.

  10. Coupling electromagnetic pulse-shaped waves into wire-like interconnection structures with a non-linear protection – Time domain calculations by the PEEC method

    Directory of Open Access Journals (Sweden)

    G. Wollenberg

    2004-01-01

    Full Text Available An interconnection system whose loads protected by a voltage suppressor and a low-pass filter against overvoltages caused by coupling pulse-shaped electromagnetic waves is analyzed. The external wave influencing the system is assumed as a plane wave with HPM form. The computation is provided by a full-wave PEEC model for the interconnection structure incorporated in the SPICE code. Thus, nonlinear elements of the protection circuit can be included in the calculation. The analysis shows intermodulation distortions and penetrations of low frequency interferences caused by intermodulations through the protection circuits. The example examined shows the necessity of using full-wave models for interconnections together with non-linear circuit solvers for simulation of noise immunity in systems protected by nonlinear devices.

  11. Hybrid simulations of whistler waves generation and current closure by a pulsed tether in the ionosphere

    Science.gov (United States)

    Chang, C. L.; Lipatov, A. S.; Drobot, A. T.; Papadopoulos, K.; Satya-Narayana, P.

    1994-01-01

    The dynamic response of a magnetized collisionless plasma to an externally driven, finite size, sudden switch-on current source across the magnetic field has been studied using a two dimensional hybrid code. It was found that the predominant plasma response was the excitation of whistler waves and the formation of current closure by induced currents in the plasma. The results show that the current closure path consists of: (a) two antiparallel field-aligned current channels at the end of the imposed current sheet; and (b) a cross-field current region connecting these channels. The formation of the current closure path occured in the whistler timescale much shorter than that of MHD and the closure region expanded continuously in time. The current closure process was accompanied by significant energy loss due to whistler radiation.

  12. Generation and controlling of the dispersive wave by femtosecond pulses propagating in the normal dispersion regimes of the birefringent photonic crystal fiber

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper studies the generation of the dispersive wave (DW) in the normal dispersion regimes of the birefringent photonic crystal fiber (BPCF) fabricated in this work. The remarkable blue-shifted radiation is found to be generated when 30 fs pulses are input in the normal dispersion regime of the BPCF for the first time. The characteristics of the blue-shifted DW strongly depend on the polarization of the input pulse. As a result, two peaks appear in the blue-shifted region of the spectrum when the input pulses polarize along the slow axis of the BPCF. With the increase of the center wavelength of the initial input pulse, the difference between the wavelengths of the two peaks widens. The peak location in the spectrum can be explained by the phase matching condition between the DW and the input pulse. In addition, when the input polarization is set to an angle of 45° with respect to the principal axes of the BPCF, the cross-phase modulation and coherent coupling between two orthogonally polarized modes would result in pulse trapping in the BPCF. Accordingly, the DW shift toward short wavelength is restrained. The DW generation in the normal-dispersion regimes of BPCF can be controlled by the phase matching condition and polarization of the input pulse.

  13. High-efficiency generation of pulsed Lyman-α radiation by resonant laser wave mixing in low pressure Kr-Ar mixture.

    Science.gov (United States)

    Saito, Norihito; Oishi, Yu; Miyazaki, Koji; Okamura, Kotaro; Nakamura, Jumpei; Louchev, Oleg A; Iwasaki, Masahiko; Wada, Satoshi

    2016-04-01

    We report an experimental generation of ns pulsed 121.568 nm Lyman-α radiation by the resonant nonlinear four-wave mixing of 212.556 nm and 845.015 nm radiation pulses providing a high conversion efficiency 1.7x10-3 with the output pulse energy 3.6 μJ achieved using a low pressure Kr-Ar mixture. Theoretical analysis shows that this efficiency is achieved due to the advantage of using (i) the high input laser intensities in combination with (ii) the low gas pressure allowing us to avoid the onset of full-scale discharge in the laser focus. In particular, under our experimental conditions the main mechanism of photoionization caused by the resonant 2-photon 212.556 nm radiation excitation of Kr atoms followed by the 1-photon ionization leads to ≈17% loss of Kr atoms and efficiency loss only by the end of the pulse. The energy of free electrons, generated by 212.556 nm radiation via (2 + 1)-photon ionization and accelerated mainly by 845.015 nm radiation, remains during the pulse below the level sufficient for the onset of full-scale discharge by the electron avalanche. Our analysis also suggests that ≈30-fold increase of 845.015 nm pulse energy can allow one to scale up the L-α radiation pulse energy towards the level of ≈100 μJ.

  14. High-efficiency generation of pulsed Lyman-α radiation by resonant laser wave mixing in low pressure Kr-Ar mixture.

    Science.gov (United States)

    Saito, Norihito; Oishi, Yu; Miyazaki, Koji; Okamura, Kotaro; Nakamura, Jumpei; Louchev, Oleg A; Iwasaki, Masahiko; Wada, Satoshi

    2016-04-01

    We report an experimental generation of ns pulsed 121.568 nm Lyman-α radiation by the resonant nonlinear four-wave mixing of 212.556 nm and 845.015 nm radiation pulses providing a high conversion efficiency 1.7x10-3 with the output pulse energy 3.6 μJ achieved using a low pressure Kr-Ar mixture. Theoretical analysis shows that this efficiency is achieved due to the advantage of using (i) the high input laser intensities in combination with (ii) the low gas pressure allowing us to avoid the onset of full-scale discharge in the laser focus. In particular, under our experimental conditions the main mechanism of photoionization caused by the resonant 2-photon 212.556 nm radiation excitation of Kr atoms followed by the 1-photon ionization leads to ≈17% loss of Kr atoms and efficiency loss only by the end of the pulse. The energy of free electrons, generated by 212.556 nm radiation via (2 + 1)-photon ionization and accelerated mainly by 845.015 nm radiation, remains during the pulse below the level sufficient for the onset of full-scale discharge by the electron avalanche. Our analysis also suggests that ≈30-fold increase of 845.015 nm pulse energy can allow one to scale up the L-α radiation pulse energy towards the level of ≈100 μJ. PMID:27137045

  15. Indices of cardiovascular function derived from peripheral pulse wave analysis using radial applanation tonometry: a measurement repeatability study.

    Science.gov (United States)

    Crilly, Mike; Coch, Christoph; Bruce, Margaret; Clark, Hazel; Williams, David

    2007-08-01

    Pulse wave analysis (PWA) using applanation tonometry is a non-invasive technique for assessing cardiovascular function. It produces three important indices: ejection duration index (ED%), augmentation index adjusted for heart rate (AIX@75), and subendocardial viability ratio (SEVR%). The aim of this study was to assess within- and between-observer repeatability of these measurements. After resting supine for 15 minutes, 20 ambulant patients (16 male) in sinus rhythm underwent four PWA measurements on a single occasion. Two nurses (A & B) independently and alternately undertook PWA measurements using the same equipment (Omron HEM-757; SphygmoCor with Millar hand-held tonometer) blind to the other nurse's PWA measurements. Within- and between-observer differences were analysed using the Bland-Altman ;limits of agreement' approach (mean difference +/- 2 standard deviations, 2SD). Mean age was 56 (blood pressure, BP 136/79; pulse rate 64). BP/PWA measurements remained stable during assessment. Based on the average of two PWA measurements the mean +/- 2SD between-observer difference in ED% was 0.3 +/- 2.0; AIX@75 1.0 +/- 3.9; and SEVR% 1.7 +/- 14.2. Based on a single PWA measurement the between-observer difference was ED% 0.3 +/- 3.3; AIX@75 1.7 +/- 6.9; and SEVR% 0.6 +/- 22.6. Within-observer differences for nurse-A were ED% 0.0 +/- 5.4; AIX@75 1.5 +/- 7.0; and SEVR% 1.7 +/- 39.0 (nurse-B: 0.1 +/- 3.8; 0.1 +/- 8.0; and 0.6 +/- 23.3, respectively). PWA demonstrates high levels of repeatability even when used by relatively inexperienced staff and has the potential to be included in the routine cardiovascular assessment of ambulant patients. PMID:17848475

  16. Evolutions of Continuous-Wave Perturbed by Pulse and Generation of Ultra-Short Pulse Trains%脉冲扰动下连续波的演化及超短脉冲串产生

    Institute of Scientific and Technical Information of China (English)

    钟先琼; 向安平; 程科; 蔡青

    2011-01-01

    Based on the nonlinear Schr(o)dinger equation and the stepped Fourier method, the shape and spectrum evolutions of continuous-wave perturbed by an optical pulse with Gaussian-typed continuum spectrum in an optical fiber are numerically simulated. The results show that, due to modulation instability in the anomalous dispersion region of the optical fiber, this pulse perturbed continuous-wave can also evolve into high-repetition-rate pulse trains, which is similar to the case of sine perturbed one. Being different from the latter case, however, the generated pulses are not equal to each other in terms of widths, intensities, and intervals. When soliton parameters are too small or the optical wave is in the normal dispersion region, only attenuation oscillation structures instead of pulse trains can be generated. And the characteristics of pulse trains or oscillation structures will vary with the soliton parameters. These evolution characteristics are obviously different from those of conventional sine perturbed continuous-waves and Gaussian optical pulses.%从光纤中非线性薛定谔方程出发,采用分步傅里叶算法数值模拟了具有高斯型连续谱的光脉冲扰动下连续波在光纤中的波形和频谱演化.结果表明,在光纤负色散区,由于调制不稳定性,该脉冲扰动下的连续波也可能像正弦波扰动下的那样演化成高重复率超短脉冲串,但构成脉冲串的各脉冲并不像正弦波扰动时那样等宽、等高、等间距.当孤子参数太小或在正色散区时,则不能形成脉冲串,只能形成衰减的振荡结构.随着孤子参数的不同,超短脉冲串及振荡结构的特点也会不同.这些演化规律与传统正弦光扰动连续波及高斯光脉冲的情形明显不同.

  17. The venous manifestations of pulse wave encephalopathy: windkessel dysfunction in normal aging and senile dementia

    International Nuclear Information System (INIS)

    Cerebral arterial, venous and cerebrospinal fluid (CSF) pulsations are closely coupled and this produces pulsation dampening or the windkessel effect. Normal pressure hydrocephalus is a manifestation of the breakdown of this windkessel effect with altered CSF and venous pulsations being noted. The aim of this study was to show that dysfunction of the windkessel mechanism is also a component of normal aging and senile dementia. The study group comprised 24 patients classified as either early senile dementia of Alzheimer's type (SDAT) or vascular dementia (VaD). The patients with dementia were compared with 12 age-matched non-cognitively impaired subjects, and 12 normal young individuals were compared with the normal aging group. MRI flow quantification was used to measure the nonpulsatile and pulsatile components of blood flow as well as the pulsation at the tentorial incisura. With normal aging blood flow decreased but arterial pulsations increased in volume by 49% (P = 0.003). The CSF vented via the tentorial incisura does not change significantly with age and therefore increased venous pulsation is necessary. In patients with VaD the arterial pulse volume was higher by 24% and the straight sinus pulsation was higher by 57% than in normal aging subjects (P = 0.05 and P = 0.03, respectively). In patients with SDAT the total venous pulsation volumes were similar to those in normal aging subjects but there was less basal sinus pulsation. Normal aging, SDAT and VaD are associated with alterations in venous pulsation due to a breakdown of the windkessel effect. (orig.)

  18. Mechanical Stimulation (Pulsed Electromagnetic Fields "PEMF" and Extracorporeal Shock Wave Therapy "ESWT") and Tendon Regeneration: A Possible Alternative.

    Science.gov (United States)

    Rosso, Federica; Bonasia, Davide E; Marmotti, Antonio; Cottino, Umberto; Rossi, Roberto

    2015-01-01

    The pathogenesis of tendon degeneration and tendinopathy is still partially unclear. However, an active role of metalloproteinases (MMP), growth factors, such as vascular endothelial growth factor (VEGF) and a crucial role of inflammatory elements and cytokines was demonstrated. Mechanical stimulation may play a role in regulation of inflammation. In vitro studies demonstrated that both pulsed electromagnetic fields (PEMF) and extracorporeal shock wave therapy (ESWT) increased the expression of pro-inflammatory cytokine such as interleukin (IL-6 and IL-10). Moreover, ESWT increases the expression of growth factors, such as transforming growth factor β(TGF-β), (VEGF), and insulin-like growth factor 1 (IGF1), as well as the synthesis of collagen I fibers. These pre-clinical results, in association with several clinical studies, suggest a potential effectiveness of ESWT for tendinopathy treatment. Recently PEMF gained popularity as adjuvant for fracture healing and bone regeneration. Similarly to ESWT, the mechanical stimulation obtained using PEMFs may play a role for treatment of tendinopathy and for tendon regeneration, increasing in vitro TGF-β production, as well as scleraxis and collagen I gene expression. In this manuscript the rational of mechanical stimulations and the clinical studies on the efficacy of extracorporeal shock wave (ESW) and PEMF will be discussed. However, no clear evidence of a clinical value of ESW and PEMF has been found in literature with regards to the treatment of tendinopathy in human, so further clinical trials are needed to confirm the promising hypotheses concerning the effectiveness of ESWT and PEMF mechanical stimulation. PMID:26617513

  19. Mechanical stimulation (pulsed electromagnetic fields "PEMF" and extracorporeal shock wave therapy "ESWT" and tendon regeneration: a possible alternative.

    Directory of Open Access Journals (Sweden)

    Federica eRosso

    2015-11-01

    Full Text Available The pathogenesis of tendon degeneration and tendinopathy is still partially unclear. However, an active role of metalloproteinases (MMP, growth factors, such as vascular endothelial growth factor (VEGF and a crucial role of inflammatory elements and cytokines was demonstrated. Mechanical stimulation may play a role in regulation of inflammation. In vitro studies demonstrated that both pulsed electromagnetic fields (PEMF and extracorporeal shock wave therapy (ESWT increased the expression of pro-inflammatory cytokine such as interleukin (IL-6 and IL-10. Moreover ESWT increases the expression of growth factors, such as transforming growth factor beta (TGF-beta, Vascular Endothelial Growth Factor (VEGF, and insulin-like growth factor 1 (IGF1, as well as the synthesis of collagen I fibers. These pre-clinical results, in association with several clinical studies, suggest a potential effectiveness of ESWT for tendinopathy treatment. Recently PEMF gained popularity as adjuvant for fracture healing and bone regeneration. Similarly to ESWT, the mechanical stimulation obtained using PEMFs may play a role for treatment of tendinopathy and for tendon regeneration, increasing in-vitro TGF-beta production, as well as scleraxis and collagen I gene expression. In this manuscript the rational of mechanical stimulations and the clinical studies on the efficacy of extracorporeal shock wave (ESW and PEMF will be discussed. However, no clear evidence of a clinical value of ESW and PEMF has been found in literature with regards to the treatment of tendinopathy in human, so further clinical trials are needed to confirm the promising hypotheses concerning the effectiveness of ESWT and PEMF mechanical stimulation.

  20. Effects of pulsed and continuous wave 902 MHz mobile phone exposure on brain oscillatory activity during cognitive processing.

    Science.gov (United States)

    Krause, Christina M; Pesonen, Mirka; Haarala Björnberg, Christian; Hämäläinen, Heikki

    2007-05-01

    The aim of the current double-blind studies was to partially replicate the studies by Krause et al. [2000ab, 2004] and to further investigate the possible effects of electromagnetic fields (EMF) emitted by mobile phones (MP) on the event-related desynchronisation/synchronisation (ERD/ERS) EEG (electroencephalogram) responses during cognitive processing. Two groups, both consisting of 36 male participants, were recruited. One group performed an auditory memory task and the other performed a visual working memory task in six exposure conditions: SHAM (no EMF), CW (continuous wave EMF) and PM (pulse modulated EMF) during both left- and right-side exposure, while the EEG was recorded. In line with our previous studies, we observed that the exposure to EMF had modest effects on brain oscillatory responses in the alpha frequency range ( approximately 8-12 Hz) and had no effects on the behavioural measures. The effects on the EEG were, however, varying, unsystematic and inconsistent with previous reports. We conclude that the effects of EMF on brain oscillatory responses may be subtle, variable and difficult to replicate for unknown reasons. PMID:17203478

  1. The effects of ischemia with and without remote conditioning on hyperemia induced decline in carotid-radial pulse wave velocity.

    Science.gov (United States)

    Onegbu, Nwamaka; Kamran, Haroon; Sharma, Bhawna; Bapat, Manasi; Littman, Stephen; Warrier, Nikhil; Patel, Rinkesh; Khalid, Muhammad Tanweer; Salciccioli, Louis; Lazar, Jason M

    2012-01-01

    Ischemic conditioning has long held promise for preventing ischemic-reperfusion (I-R) injury. Although a number of studies have evaluated the effects of brief repeated episodes of ischemia before a prolonged ischemic episode on the cardiovascular system using clinical endpoints, more sensitive techniques by which to measure its effects are lacking. Since endothelial function is sensitive to I-R injury, flow mediated dilation of the brachial artery has been proposed for this purpose, but has significant limitations. Hyperemia normally decreases carotid to radial pulse wave velocity (PWV). Accordingly, we sought to determine the effects of I-R injury and ischemic conditioning on the hyperemic change (Δ) in PWV. We induced hyperemia by release of arterial cuff occlusion before and after ipsilateral arm I-R injury (7.5min occlusion) in 25 healthy males, age 29±6 years. The protocol was repeated on 2 occasions in combination with either pre- or post- conditioning stimuli (3× 30s contralateral arm occlusions). Hyperemia resulted in a significant decrease (-13.7%, pconditioning restored the PWV decline (pre: -11.0%, pconditioning restores this response. This technique may be useful for the assessment of novel treatment strategies and mechanisms underlying remote pre- and post-ischemic conditioning in protecting the cardiovascular system.

  2. Extensional flow of low-viscosity fluids in capillary bridges formed by pulsed surface acoustic wave jetting

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, P K; McDonnell, A G; Prabhakar, R; Yeo, L Y; Friend, J, E-mail: james.friend@monash.edu.au [MicroNanophysics Research Laboratory, Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC 3800 (Australia); Melbourne Centre for Nanofabrication, Melbourne, VIC 3800 (Australia)

    2011-02-15

    Forming capillary bridges of low-viscosity ({approx}<10 mPa s) fluids is difficult, making the study of their capillary-thinning behavior and the measurement of the fluid's extensional viscosity difficult as well. Current techniques require some time to form a liquid bridge from the stretching of a droplet. Rapidly stretching a liquid bridge using these methods can cause its breakup if the viscosity is too low. Stretching more slowly allows the bridge to thin and break up before a suitable bridge geometry can be established to provide reliable and accurate rheological data. Using a pulsed surface acoustic wave to eject a jet from a sessile droplet, a capillary bridge may be formed in about 7.5 ms, about seven times quicker than current methods. With this approach, capillary bridges may be formed from Newtonian and non-Newtonian fluids having much lower viscosities-water, 0.04% by weight solution of high-molecular-weight (7 MDa) polystyrene in dioctyl phthalate and 0.25% fibrinogen solution in demineralized water, for example. Details of the relatively simple system used to achieve these results are provided, as are experimental results indicating deviations from a Newtonian response by the low-viscosity non-Newtonian fluids used in our study.

  3. Design and implementation of a smartphone-based portable ultrasound pulsed-wave Doppler device for blood flow measurement.

    Science.gov (United States)

    Huang, Chih-Chung; Lee, Po-Yang; Chen, Pay-Yu; Liu, Ting-Yu

    2012-01-01

    Blood flow measurement using Doppler ultrasound has become a useful tool for diagnosing cardiovascular diseases and as a physiological monitor. Recently, pocket-sized ultrasound scanners have been introduced for portable diagnosis. The present paper reports the implementation of a portable ultrasound pulsed-wave (PW) Doppler flowmeter using a smartphone. A 10-MHz ultrasonic surface transducer was designed for the dynamic monitoring of blood flow velocity. The directional baseband Doppler shift signals were obtained using a portable analog circuit system. After hardware processing, the Doppler signals were fed directly to a smartphone for Doppler spectrogram analysis and display in real time. To the best of our knowledge, this is the first report of the use of this system for medical ultrasound Doppler signal processing. A Couette flow phantom, consisting of two parallel disks with a 2-mm gap, was used to evaluate and calibrate the device. Doppler spectrograms of porcine blood flow were measured using this stand-alone portable device under the pulsatile condition. Subsequently, in vivo portable system verification was performed by measuring the arterial blood flow of a rat and comparing the results with the measurement from a commercial ultrasound duplex scanner. All of the results demonstrated the potential for using a smartphone as a novel embedded system for portable medical ultrasound applications. PMID:22293750

  4. Pulse Pressure in Clinical Practice

    Directory of Open Access Journals (Sweden)

    Jiri Parenica

    2012-02-01

    Full Text Available The review presents basic information about the pulse pressure. The variables related to pulse pressure are briefly explained - arterial stiffness, arterial compliance, pulse wave velocity, pulse pressure amplification and augmentation index. We present some recent trials and observational studies that show the importance of pulse pressure in clinical practice. Briefly the possibilities of influencing the pulse pressure are discussed.

  5. Non-Invasive Pulse Wave Analysis in a Thrombus-Free Abdominal Aortic Aneurysm after Implantation of a Nitinol Aortic Endograft.

    Science.gov (United States)

    Georgakarakos, Efstratios; Argyriou, Christos; Georgiadis, George S; Lazarides, Miltos K

    2015-01-01

    Endovascular aneurysm repair has been associated with changes in arterial stiffness, as estimated by pulse wave velocity (PWV). This marker is influenced by the medical status of the patient, the elastic characteristics of the aneurysm wall, and the presence of intraluminal thrombus. Therefore, in order to delineate the influence of the endograft implantation in the early post-operative period, we conducted non-invasively pulse wave analysis in a male patient with an abdominal aortic aneurysm containing no intraluminal thrombus, unremarkable past medical history, and absence of peripheral arterial disease. The estimated parameters were the systolic and diastolic pressure calculated at the aortic level (central pressures), PWV, augmentation pressure (AP) and augmentation index (AI), pressure wave reflection magnitude (RM), and peripheral resistance. Central systolic and diastolic pressure decreased post-operatively. PWV showed subtle changes from 11.6 to 10.6 and 10.9 m/s at 1-week and 1-month, respectively. Accordingly, the AI decreased from 28 to 14% and continued to drop to 25%. The AP decreased gradually from 15 to 6 and 4 mmHg. The wave RM dropped from 68 to 52% at 1-month. Finally, the peripheral resistance dropped from 1.41 to 0.99 and 0.85 dyn × s × cm(-5). Our example shows that the implantation of an aortic endograft can modify the pressure wave reflection over the aortic bifurcation without causing significant alterations in PWV. PMID:26793712

  6. Generation of Shear Alfvén Waves by Repetitive High Power Microwave Pulses Near the Electron Plasma Frequency - A laboratory study of a ``Virtual Antenna''

    Science.gov (United States)

    Wang, Yuhou; Gekelman, Walter; Pribyl, Patrick; van Compernolle, Bart; Papadopoulos, Konstantinos

    2015-11-01

    ELF / ULF waves are important in terrestrial radio communications but difficult to launch using ground-based structures due to their enormous wavelengths. In spite of this generation of such waves by field-aligned ionospheric heating modulation was first demonstrated using the HAARP facility. In the future heaters near the equator will be constructed and laboratory experiments on cross-field wave propagation could be key to the program's success. Here we report a detailed laboratory study conducted on the Large Plasma Device (LaPD) at UCLA. In this experiment, ten rapid pulses of high power microwaves (250 kW X-band) near the plasma frequency were launched transverse to the background field, and were modulated at a variable fraction (0.1-1.0) of fci. Along with bulk electron heating and density modification, the microwave pulses generated a population of fast electrons. The field-aligned current carried by the fast electrons acted as an antenna that radiated shear Alfvén waves. It was demonstrated that a controllable arbitrary frequency (f wave can be generated by this method. The radiation pattern, frequency variation and power dependence of the virtual antenna is also presented. This work is supported by an AFOSR MURI award, and conducted at the Basic Plasma Science Facility at UCLA funded by DoE and NSF.

  7. Energetic mid-IR femtosecond pulse generation by self-defocusing soliton-induced dispersive waves in a bulk quadratic nonlinear crystal

    CERN Document Server

    Zhou, B B; Bache, M

    2014-01-01

    Generating energetic femtosecond mid-IR pulses is crucial for ultrafast spectroscopy, and currently relies on parametric processes that, while efficient, are also complex. Here we experimentally show a simple alternative that uses a single pump wavelength without any pump synchronization and without critical phase-matching requirements. Pumping a bulk quadratic nonlinear crystal (unpoled LiNbO$_3$ cut for noncritical phase-mismatched interaction) with sub-mJ near-IR 50-fs pulses, tunable and broadband ($\\sim 1,000$ cm$^{-1}$) mid-IR pulses around $3.0~\\mu\\rm m$ are generated with excellent spatio-temporal pulse quality, having up to 10.5 $\\mu$J energy (6.3% conversion). The mid-IR pulses are dispersive waves phase-matched to near-IR self-defocusing solitons created by the induced self-defocusing cascaded nonlinearity. This process is filament-free and the input pulse energy can therefore be scaled arbitrarily by using large-aperture crystals. The technique can readily be implemented with other crystals and la...

  8. Dissipative rogue waves induced by long-range chaotic multi-pulse interactions in a fiber laser with a topological insulator-deposited microfiber photonic device.

    Science.gov (United States)

    Liu, Meng; Cai, Ze-Rong; Hu, Song; Luo, Ai-Ping; Zhao, Chu-Jun; Zhang, Han; Xu, Wen-Cheng; Luo, Zhi-Chao

    2015-10-15

    We reported on the generation of dissipative rogue waves (DRWs) induced by long-range chaotic multi-pulse interactions in a fiber laser based on a topological insulator (TI)-deposited microfiber photonic device. By virtue of the simultaneous saturable absorption effect and high nonlinearity provided by the TI-deposited microfiber, a localized, chaotic multi-pulse wave packet with strong long-range nonlinear interactions could be obtained, which gives rise to the formation of DRWs. The results might enhance the understanding of DRWs in optical systems, and further demonstrated that the TI-deposited microfiber could be considered as an excellent photonic device with both saturable absorption and highly nonlinear effects for the application field of nonlinear optics. PMID:26469615

  9. Ethnic differences in and childhood influences on early adult pulse wave velocity: the Determinants of Adolescent, Now Young Adult, Social Wellbeing, and Health longitudinal study

    OpenAIRE

    Cruickshank, J Kennedy; Silva, Maria J.; Molaodi, Oarabile R.; Enayat, Zinat E.; Cassidy, Aidan; Karamanos, Alexis; Read, Ursula M.; Faconti, Luca; Dall, Philippa; Stansfield, Ben; Harding, Seeromanie

    2016-01-01

    Early determinants of aortic stiffness as pulse wave velocity are poorly understood. We tested how factors measured twice previously in childhood in a multiethnic cohort study, particularly body mass, blood pressure, and objectively assessed physical activity affected aortic stiffness in young adults. Of 6643 London children, aged 11 to 13 years, from 51 schools in samples stratified by 6 ethnic groups with different cardiovascular risk, 4785 (72%) were seen again at aged 14 to 16 years. In 2...

  10. Ethnic differences in and childhood influences on early adult pulse wave velocity:The determinants of adolescent, now young adult, social wellbeing, and health longitudinal study

    OpenAIRE

    Cruickshank, J Kennedy; Silva, Maria J.; Molaodi, Oarabile R.; Enayat, Zinat E.; Cassidy, Aidan; Karamanos, Alexis; Read, Ursula M.; Faconti, Luca; Dall, Philippa; Stansfield, Ben; Harding, Seeromanie

    2016-01-01

    Early determinants of aortic stiffness as pulse wave velocity are poorly understood. We tested how factors measured twice previously in childhood in a multiethnic cohort study, particularly body mass, blood pressure, and objectively assessed physical activity affected aortic stiffness in young adults. Of 6643 London children, aged 11 to 13 years, from 51 schools in samples stratified by 6 ethnic groups with different cardiovascular risk, 4785 (72%) were seen again at aged 14 to 16 years. In 2...

  11. Mechanical Stimulation (Pulsed Electromagnetic Fields “PEMF” and Extracorporeal Shock Wave Therapy “ESWT”) and Tendon Regeneration: A Possible Alternative

    OpenAIRE

    Federica eRosso; Davide Edoardo Bonasia; Antonio eMarmotti; Umberto eCottino; Roberto eRossi

    2015-01-01

    The pathogenesis of tendon degeneration and tendinopathy is still partially unclear. However, an active role of metalloproteinases (MMP), growth factors, such as vascular endothelial growth factor (VEGF) and a crucial role of inflammatory elements and cytokines was demonstrated. Mechanical stimulation may play a role in regulation of inflammation. In vitro studies demonstrated that both pulsed electromagnetic fields (PEMF) and extracorporeal shock wave therapy (ESWT) increased the expression ...

  12. On mean wind and turbulence profile measurements from ground-based wind lidars:limitations in time and space resolution with continuous wave and pulsed lidar systems

    OpenAIRE

    Mikkelsen, Torben

    2009-01-01

    Two types of wind lidar?s have become available for ground-based vertical mean wind and turbulence profiling. A continuous wave (CW) wind lidar, and a pulsed wind lidar. Although they both are build upon the same recent 1.55 μ telecom fibre technology, they possess fundamental differences between their temporal and spatial resolution capabilities. A literature review of the two lidar systems spatial and temporal resolution characteristics will be presented, and the implication for the two lid...

  13. Effect of Pulsed Wave Low-Level Laser Therapy on Tibial Complete Osteotomy Model of Fracture Healing With an Intramedullary Fixation

    OpenAIRE

    Mostafavinia, Atarodalsadat; Masteri Farahani, Reza; Abbasian, Mohammadreza; Vasheghani Farahani, Mohammadmehdi; Fridoni, Mohammadjavad; Zandpazandi, Sara; GHOREISHI, Seyed Kamran; Abdollahifar, Mohammad Amin; Pouriran, Ramin; Bayat, Mohammad

    2015-01-01

    Background: Fractures pose a major worldwide challenge to public health, causing tremendous disability for the society and families. According to recent studies, many in vivo and in vitro experiments have shown the positive effects of PW LLLT on osseous tissue. Objectives: The aim of this study was to evaluate the outcome of infrared pulsed wave low-level laser therapy (PW LLLT) on the fracture healing process in a complete tibial osteotomy in a rat model, which was stabilized by an intramedu...

  14. Coupled-mode theory for electromagnetic pulse propagation in dispersive media undergoing a spatio-temporal perturbation - exact derivation, numerical validation and peculiar wave mixing

    CERN Document Server

    Sivan, Y; Halstuch, A

    2016-01-01

    We present an extension of the canonical coupled mode theory of electromagnetic waves to the case of pulses and spatio-temporal perturbations in complex media. Unlike previous attempts to derive such a model, our approach involves no approximation, and does not impose any restriction on the spatio-temporal profile. Moreover, the effect of modal dispersion on mode evolution and on the coupling to other modes is fully taken into account. Thus, our approach can yield any required accuracy by retaining as many terms in the expansion as needed. It also avoids various artifacts of previous derivations by introducing the correct form of the solution. We then provide what is, to the best of our knowledge, the first ever validation of the coupled mode equations with exact numerical simulations, and demonstrate the wide range of possibilities enabled by spatio-temporal perturbations of pulses, including pulse shortening or broadening or more complex shaping. Our formulation is valid across the electromagnetic spectrum,...

  15. Photoelectron circular dichroism in the multiphoton ionization by short laser pulses. I. Propagation of single-active-electron wave packets in chiral pseudo-potentials

    International Nuclear Information System (INIS)

    A theoretical method to study the angle-resolved multiphoton ionization of polyatomic molecules is developed. It is based on the time-dependent formulation of the Single Center (TDSC) method and consists in the propagation of single-active-electron wave packets in the effective molecular potentials in the presence of intense laser pulses. For this purpose, the time-dependent Schrödinger equation for one electron, moving in a molecular field and interacting with an arbitrary laser pulse, is solved in spherical coordinates by an efficient numerical approach. As a test, the method is applied to the one- and two-photon ionizations of a model methane-like chiral system by circularly polarized short intense high-frequency laser pulses. Thereby, we analyze the photoelectron circular dichroism (PECD) in the momentum distribution. The considered model application illustrates the capability of the TDSC method to study multiphoton PECD in fixed-in-space and randomly oriented chiral molecules

  16. Directional spectra of ocean waves from microwave backscatter: A physical optics solution with application to the short-pulse and two-frequency measurement techniques

    Science.gov (United States)

    Jackson, F. C.

    1979-01-01

    Two simple microwave radar techniques that are potentially capable of providing routine satellite measurements of the directional spectrum of ocean waves were developed. One technique, the short pulse technique, makes use of very short pulses to resolve ocean surface wave contrast features in the range direction; the other technique, the two frequency correlation technique makes use of coherency in the transmitted waveform to detect the large ocean wave contrast modulation as a beat or mixing frequency in the power backscattered at two closely separated microwave frequencies. A frequency domain analysis of the short pulse and two frequency systems shows that the two measurement systems are essentially duals; they each operate on the generalized (three frequency) fourth-order statistical moment of the surface transfer function in different, but symmetrical ways, and they both measure the same directional contrast modulation spectrum. A three dimensional physical optics solution for the fourth-order moment was obtained for backscatter in the near vertical, specular regime, assuming Gaussian surface statistics.

  17. Relativistic spherical plasma waves

    Science.gov (United States)

    Bulanov, S. S.; Maksimchuk, A.; Schroeder, C. B.; Zhidkov, A. G.; Esarey, E.; Leemans, W. P.

    2012-02-01

    Tightly focused laser pulses that diverge or converge in underdense plasma can generate wake waves, having local structures that are spherical waves. Here we study theoretically and numerically relativistic spherical wake waves and their properties, including wave breaking.

  18. Effective transvascular drug delivery to glioma in rats by using a pulsed laser-induced photomechanical wave (Conference Presentation)

    Science.gov (United States)

    Akutsu, Yusuke; Sato, Shunichi; Tomiyama, Arata; Tsunoi, Yasuyuki; Kawauchi, Satoko; Mori, Kentaro; Terakawa, Mitsuhiro

    2016-03-01

    Glioma is one of the most aggressive cancers, for which efficacy of conventional chemotherapy is often limited due to the blood-tumor barrier (BTB). Thus, the development of a method for enhancing the BTB permeability is strongly desired. In this study, we applied a photomechanical wave (PMW), which was generated by the irradiation of a light-absorbing material with a nanosecond laser pulse, to transiently open the BTB in a rat intracranial glioma model using C6 cells. A tumor was grown in the both hemispheres, and a solution of Evans blue (EB), as a test drug, was injected into the tail vein. Thereafter, we applied a PMW generated at a laser fluence of 0.2 J/cm2 (averaged peak pressure, ~27 MPa), 0.4 J/cm2 (~54 MPa) or 0.6 J/cm2 (~78MPa), to one hemisphere through the cranial window, while the other hemisphere served as a control. Four hours later, the rat was perfused, and we compared intensity distributions of EB fluorescence between the both hemispheres. Intensities of EB fluorescence both in the peritumoral and tumor core regions were increased with increasing the laser fluence, but hemorrhage was observed at the highest fluence. Thus, 0.4 J/cm2 would be optimum for efficient and safe BTB opening. On the basis of fluorescence microscopy with the use of enhanced green fluorescent protein-expressing C6 cells, we confirmed that a drug was delivered into targeted glioma cells in the peritumoral region. These results show the validity of the present transvascular drug delivery method to glioma.

  19. Identifying coronary artery disease in men with type 2 diabetes: osteoprotegerin, pulse wave velocity, and other biomarkers of cardiovascular risk.

    LENUS (Irish Health Repository)

    Davenport, Colin

    2012-02-01

    OBJECTIVES: In patients with type 2 diabetes, high serum levels of osteoprotegerin (OPG) have been associated with a greater risk of cardiovascular events. However, it remains unclear how well OPG performs when compared with traditional biomarkers of cardiovascular risk such as high-sensitivity C-reactive protein (hsCRP). Furthermore, OPG levels are also high in the presence of diabetes-related microvascular disease, and it is unclear whether OPG can distinguish microvascular disease from large-vessel atherosclerosis. The first aim of this study was to compare OPG levels against other biomarkers of cardiovascular risk in the identification of patients with documented multivessel coronary artery disease (CAD). The second aim was to compare OPG levels in patients with microvascular complications (microalbuminuria) against those with established CAD. METHODS: Three groups of male patients with type 2 diabetes were recruited: patients without microvascular complications or large-vessel atherosclerosis (n = 24), patients with microalbuminuria only (n = 23), and patients with microalbuminuria and documented multivessel CAD (n = 25). OPG, hsCRP, interleukin 6, urate, and pulse wave velocity were measured. RESULTS: Serum OPG levels were significantly higher in patients with a combination of microalbuminuria and CAD than in those with microalbuminuria alone. There were no significant differences in any of the other biomarkers between the groups. CONCLUSION: OPG was found to be superior to the other biomarkers studied in identifying patients with documented CAD. The presence of CAD was a greater determinant of serum OPG levels than microalbuminuria in our population. These findings support the use of OPG as a biomarker of cardiovascular risk.

  20. NON-INVASIVE PULSE WAVE ANALYSIS IN A THROMBUS-FREE ABDOMINAL AORTIC ANEURYSM AFTER IMPLANTATION OF A NITINOL AORTIC ENDOGRAFT.

    Directory of Open Access Journals (Sweden)

    Efstratios eGeorgakarakos

    2016-01-01

    Full Text Available Endovascular Aneurysm Repair has been associated with changes in arterial stiffness, as estimated by pulse wave velocity (PWV. This marker is influenced by the medical status of the patient, the elastic characteristics of the aneurysm wall and the intraluminal thrombus. Therefore, in order to delineate the influence of the endograft implantation in the early postoperative period, we conducted non-invasively pulse wave analysis in a male patient with an abdominal aortic aneurysm of no intraluminal thrombus, no medical history and absence of peripheral arterial disease. Central systolic and diastolic pressure decreased postoperatively. PWV showed subtle changes from 11.6m/sec to 10.6 and 10.9 at 1-week and 1-month, respectively. Accordingly, the augmentation index decreased from 28% to 14% and continued to drop to 25%. The augmentation pressure decreased gradually from 15- to 6- and 4mmHg. The wave reflection magnitude dropped from 68% to 52% at 1-month. Finally, the peripheral resistance dropped from 1.41 to 0.99 and 0.85 dyn×sec×cm−5. Our example shows that the implantation of an aortic endograft can modify the wave reflection in aorta without causing significant alterations in PWV.

  1. Generation of quasi-monoenergetic heavy ion beams via staged shock wave acceleration driven by intense laser pulses in near-critical plasmas

    Science.gov (United States)

    Zhang, W. L.; Qiao, B.; Shen, X. F.; You, W. Y.; Huang, T. W.; Yan, X. Q.; Wu, S. Z.; Zhou, C. T.; He, X. T.

    2016-09-01

    Laser-driven ion acceleration potentially offers a compact, cost-effective alternative to conventional accelerators for scientific, technological, and health-care applications. A novel scheme for heavy ion acceleration in near-critical plasmas via staged shock waves driven by intense laser pulses is proposed, where, in front of the heavy ion target, a light ion layer is used for launching a high-speed electrostatic shock wave. This shock is enhanced at the interface before it is transmitted into the heavy ion plasmas. Monoenergetic heavy ion beam with much higher energy can be generated by the transmitted shock, comparing to the shock wave acceleration in pure heavy ion target. Two-dimensional particle-in-cell simulations show that quasi-monoenergetic {{{C}}}6+ ion beams with peak energy 168 MeV and considerable particle number 2.1 × {10}11 are obtained by laser pulses at intensity of 1.66 × {10}20 {{W}} {{cm}}-2 in such staged shock wave acceleration scheme. Similarly a high-quality {{Al}}10+ ion beam with a well-defined peak with energy 250 MeV and spread δ E/{E}0=30 % can also be obtained in this scheme.

  2. Mathematical Modeling of Pulse Wave Based on Lognormal Function%基于 Lognormal 函数的脉搏波数学建模

    Institute of Scientific and Technical Information of China (English)

    赵海; 窦圣昶; 李大舟; 陈星池

    2016-01-01

    对健康的日常监测,时间长,数据量大。为了简化数据量,分析了现有的使用2~4个高斯函数拟合脉搏波的脉搏波数学建模方法,在此基础上,提出了 Lognormal 函数模型的数学建模方法。使用 4个Lognormal 函数对脉搏波的一个周期进行拟合建模,以脉搏波的生理特性为基础调整 4个 Lognormal 函数的起始时间点,并对其性能进行了分析对比。结果表明,与现有方法相比,Lognormal 函数模型不仅有更高的拟合精确度,而且有更优的计算复杂度,更适合以日常健康监测为目的的体域网健康大数据应用。%Daily monitoring health status needs long time,so the amount of health data is massive.In order to simplify the data,the existing mathematical methods of modeling pulse wave were analyzed which use two to four Gauss function to fit the pulse wave.Then,the mathematical modeling method of pulse wave based on Lognormal function was presented.A cycle of pulse wave was modeled by using four Lognormal functions.The starting time points of the four Lognormal functions were adjusted based on the physiological characteristics of the pulse wave, and the performance of the model was analyzed and compared with the existing methods.The results show that,compared with the existing methods,the Lognormal function model not only has a higher fitting accuracy,but also has better computational complexity,thus being more suitable for the big data application to daily health monitor in the body area network.

  3. Spin wave mediated unidirectional vortex core reversal by two orthogonal monopolar field pulses: The essential role of three-dimensional magnetization dynamics

    Science.gov (United States)

    Noske, Matthias; Stoll, Hermann; Fähnle, Manfred; Gangwar, Ajay; Woltersdorf, Georg; Slavin, Andrei; Weigand, Markus; Dieterle, Georg; Förster, Johannes; Back, Christian H.; Schütz, Gisela

    2016-05-01

    Scanning transmission x-ray microscopy is employed to investigate experimentally the reversal of the magnetic vortex core polarity in cylindrical Ni81Fe19 nanodisks triggered by two orthogonal monopolar magnetic field pulses with peak amplitude B0, pulse length τ = 60 ps , and delay time Δ t in the range from - 400 ps to + 400 ps between the two pulses. The two pulses are oriented in-plane in the x- and y-directions. We have experimentally studied vortex core reversal as a function of B0 and Δ t . The resulting phase diagram shows large regions of unidirectional vortex core switching where the switching threshold is modulated due to resonant amplification of azimuthal spin waves. The switching behavior changes dramatically depending on whether the first pulse is applied in the x- or the y-direction. This asymmetry can be reproduced by three-dimensional micromagnetic simulations but not by two-dimensional simulations. This behavior demonstrates that in contrast to the previous experiments on vortex core reversal, the three-dimensionality in the dynamics is essential here.

  4. Spin wave and percolation studies in epitaxial La2/3Sr1/3MnO3 thin films grown by pulsed laser deposition

    Science.gov (United States)

    Ettayfi, A.; Moubah, R.; Hlil, E. K.; Colis, S.; Lenertz, M.; Dinia, A.; Lassri, H.

    2016-07-01

    We investigate the magnetic and transport properties of high quality La2/3Sr1/3MnO3 thin films grown by pulsed laser deposition. X-ray diffraction shows that the deposited films are epitaxial with the expected pseudo-cubic structure. Using the spin wave theory, the temperature dependence of magnetization was satisfactory modeled at low temperature, in which several fundamental magnetic parameters were obtained (spin wave stiffness, exchange constants, Fermi wave-vector, Mn-Mn interatomic distance). The transport properties were studied via the temperature dependence of electrical resistivity [ρ(T)], which shows a peak at Curie temperature due to metal to insulator transition. The percolation theory was used to simulate ρ(T) in both the ferromagnetic and paramagnetic phases. Reasonable agreement with the experimental data is reported.

  5. Investigation of acoustic waves generated in an elastic solid by a pulsed ion beam and their application in a FIB based scanning ion acoustic microscope

    International Nuclear Information System (INIS)

    The aim of this work is to investigate the acoustic wave generation by pulsed and periodically modulated ion beams in different solid materials depending on the beam parameters and to demonstrate the possibility to apply an intensity modulated focused ion beam (FIB) for acoustic emission and for nondestructive investigation of the internal structure of materials on a microscopic scale. The combination of a FIB and an ultrasound microscope in one device can provide the opportunity of nondestructive investigation, production and modification of micro- and nanostructures simultaneously. This work consists of the two main experimental parts. In the first part the process of elastic wave generation during the irradiation of metallic samples by a pulsed beam of energetic ions was investigated in an energy range from 1.5 to 10 MeV and pulse durations of 0.5-5 μs, applying ions with different masses, e.g. oxygen, silicon and gold, in charge states from 1+ to 4+. The acoustic amplitude dependence on the ion beam parameters like the ion mass and energy, the ion charge state, the beam spot size and the pulse duration were of interest. This work deals with ultrasound transmitted in a solid, i.e. bulk waves, because of their importance for acoustic transmission microscopy and nondestructive inspection of internal structure of a sample. The second part of this work was carried out using the IMSA-100 FIB system operating in an energy range from 30 to 70 keV. The scanning ion acoustic microscope based on this FIB system was developed and tested. (orig.)

  6. Consistency of aortic distensibility and pulse wave velocity estimates with respect to the Bramwell-Hill theoretical model: a cardiovascular magnetic resonance study

    Directory of Open Access Journals (Sweden)

    De Cesare Alain

    2011-01-01

    Full Text Available Abstract Background Arterial stiffness is considered as an independent predictor of cardiovascular mortality, and is increasingly used in clinical practice. This study aimed at evaluating the consistency of the automated estimation of regional and local aortic stiffness indices from cardiovascular magnetic resonance (CMR data. Results Forty-six healthy subjects underwent carotid-femoral pulse wave velocity measurements (CF_PWV by applanation tonometry and CMR with steady-state free-precession and phase contrast acquisitions at the level of the aortic arch. These data were used for the automated evaluation of the aortic arch pulse wave velocity (Arch_PWV, and the ascending aorta distensibility (AA_Distc, AA_Distb, which were estimated from ascending aorta strain (AA_Strain combined with either carotid or brachial pulse pressure. The local ascending aorta pulse wave velocity AA_PWVc and AA_PWVb were estimated respectively from these carotid and brachial derived distensibility indices according to the Bramwell-Hill theoretical model, and were compared with the Arch_PWV. In addition, a reproducibility analysis of AA_PWV measurement and its comparison with the standard CF_PWV was performed. Characterization according to the Bramwell-Hill equation resulted in good correlations between Arch_PWV and both local distensibility indices AA_Distc (r = 0.71, p AA_Distb (r = 0.60, p Arch_PWV and both theoretical local indices AA_PWVc (r = 0.78, p AA_PWVb (r = 0.78, p Arch_PWV was well related to CF_PWV (r = 0.69, p Conclusions The present work confirmed the consistency and robustness of the regional index Arch_PWV and the local indices AA_Distc and AA_Distb according to the theoretical model, as well as to the well established measurement of CF_PWV, demonstrating the relevance of the regional and local CMR indices.

  7. Beneficial effects on arterial stiffness and pulse-wave reflection of combined enalapril and candesartan in chronic kidney disease--a randomized trial.

    Directory of Open Access Journals (Sweden)

    Marie Frimodt-Møller

    Full Text Available BACKGROUND: Cardiovascular disease (CVD is highly prevalent in patients with chronic kidney disease (CKD. Inhibition of the renin-angiotensinsystem (RAS in hypertension causes differential effects on central and brachial blood pressure (BP, which has been translated into improved outcome. The objective was to examine if a more complete inhibition of RAS by combining an angiotensin converting enzyme inhibitor (ACEI and an angiotensin receptor antagonist (ARB compared to monotherapy has an additive effect on central BP and pulse-wave velocity (PWV, which are known markers of CVD. METHODS: Sixty-seven CKD patients (mean GFR 30, range 13-59 ml/min/1.73 m(2 participated in an open randomized study of 16 weeks of monotherapy with either enalapril or candesartan followed by 8 weeks of dual blockade aiming at a total dose of 16 mg candesartan and 20 mg enalapril o.d. Pulse-wave measurements were performed at week 0, 8, 16 and 24 by the SphygmoCor device. RESULTS: Significant additive BP independent reductions were found after dual blockade in aortic PWV (-0.3 m/s, P<0.05 and in augmentation index (-2%, P<0.01 compared to monotherapy. Furthermore pulse pressure amplification was improved (P<0.05 and central systolic BP reduced (-6 mmHg, P<0.01. CONCLUSIONS: Dual blockade of the RAS resulted in an additive BP independent reduction in pulse-wave reflection and arterial stiffness compared to monotherapy in CKD patients. TRIAL REGISTRATION: Clinical trial.gov NCT00235287.

  8. Investigation of acoustic waves generated in an elastic solid by a pulsed ion beam and their application in a FIB based scanning ion acoustic microscope

    Energy Technology Data Exchange (ETDEWEB)

    Akhmadaliev, C.

    2004-12-01

    The aim of this work is to investigate the acoustic wave generation by pulsed and periodically modulated ion beams in different solid materials depending on the beam parameters and to demonstrate the possibility to apply an intensity modulated focused ion beam (FIB) for acoustic emission and for nondestructive investigation of the internal structure of materials on a microscopic scale. The combination of a FIB and an ultrasound microscope in one device can provide the opportunity of nondestructive investigation, production and modification of micro- and nanostructures simultaneously. This work consists of the two main experimental parts. In the first part the process of elastic wave generation during the irradiation of metallic samples by a pulsed beam of energetic ions was investigated in an energy range from 1.5 to 10 MeV and pulse durations of 0.5-5 {mu}s, applying ions with different masses, e.g. oxygen, silicon and gold, in charge states from 1{sup +} to 4{sup +}. The acoustic amplitude dependence on the ion beam parameters like the ion mass and energy, the ion charge state, the beam spot size and the pulse duration were of interest. This work deals with ultrasound transmitted in a solid, i.e. bulk waves, because of their importance for acoustic transmission microscopy and nondestructive inspection of internal structure of a sample. The second part of this work was carried out using the IMSA-100 FIB system operating in an energy range from 30 to 70 keV. The scanning ion acoustic microscope based on this FIB system was developed and tested. (orig.)

  9. Signal analysis of human pulse wave based on blind deconvolution%基于盲解卷问题的脉搏波的信号分析

    Institute of Scientific and Technical Information of China (English)

    李绪彤; 亓慧; 邹华伟

    2005-01-01

    BACKGROUND:The human body pulse signal can be regarded as the convolution of the heart excitation resource signal and the pulse transfer system. The backward signal was studied more before, but the research to the forward signal is not enough.OBJECTIVE: To extract the heart excitation source signals in human pulse wave.DESIGN: A randomized controlled design.SETTING: Second Affiliated Hospital of China Medical University;Biomedical Engineering institute of Shandong University.PARTICIPANTS: Health physical-examined persons in the Second Affiliated Hospital of China Medical University on March 11,2004 were recurited. RM6240 physiological signals collection system was adopted.METHODS: The collection of pulse wave in healthy persons was input into system-analysis mode and based on the principle of blind deconvolution and feasible arithmetic, heart source signals were obtained.MAIN OUTCOME MEASURES: ①Normal human pulse wave ②The heart excitation source signals.RESULTS: In the back-half segment of cepstrum (n> n0), periodic impulse was in accordance with the basic human pulse frequency. There was an excitation source in the pulse wave. If high-pass filter was defined to the signal (when n0 equals to 30 in the experimentation the result will be best.), we could get the heart excitation source signal after it was filtered, F transformation, index and inverse transformation.CONCLUSION: This method is practical and feasible and will provide a basis to further analyze pulse wave.%背景:人体脉搏信号可以看作是心脏源的激励信号和脉搏系统冲激响应的卷积,目前对脉搏冲激响应有了较详细的认识,但是对激励源信号的研究还需深入.目的:提取心脏激励源信号的特征波形.设计:随机对照实验.单位:中国医科大学附属第二医院,山东大学生物医学工程所.对象:2004-3-11在中国医科大学附属第二医院体检的身体健康的成年人.RM6240多道生理信号采集

  10. Method of optical self-mixing for pulse wave transit time in comparison with other methods and correlation with blood pressure

    Science.gov (United States)

    Meigas, Kalju; Lass, Jaanus; Kattai, Rain; Karai, Deniss; Kaik, Juri

    2004-07-01

    This paper is a part of research to develop convenient method for continuous monitoring of arterial blood pressure by non-invasive and non-oscillometric way. A simple optical method, using self-mixing in a diode laser, is used for detection of skin surface vibrations near the artery. These vibrations, which can reveal the pulsate propagation of blood pressure waves along the vasculature, are used for pulse wave registration. The registration of the Pulse Wave Transit Time (PWTT) is based on computing the time delay in different regions of the human body using an ECG as a reference signal. In this study, the comparison of method of optical self-mixing with other methods as photoplethysmographic (PPG) and bioimpedance (BI) for PWTT is done. Also correlation of PWTT, obtained with different methods, with arterial blood pressure is calculated. In our study, we used a group of volunteers (34 persons) who made the bicycle exercise test. The test consisted of cycling sessions of increasing workloads during which the HR changed from 60 to 180 beats per minute. In addition, a blood pressure (NIBP) was registered with standard sphygmomanometer once per minute during the test and all NIBP measurement values were synchronized to other signals to find exact time moments where the systolic blood pressure was detected (Korotkoff sounds starting point). Computer later interpolated the blood pressure signal in order to get individual value for every heart cycle. The other signals were measured continuously during all tests. At the end of every session, a recovery period was included until person's NIBP and heart rate (HR) normalized. As a result of our study it turned out that time intervals that were calculated from plethysmographic (PPG) waveforms were in the best correlation with systolic blood pressure. The diastolic pressure does not correlate with any of the parameters representing PWTT. The pulse wave signals measured by laser and piezoelectric transducer are very similar

  11. Transcranial magnetic stimulation with a half-sine wave pulse elicits direction-specific effects in human motor cortex

    DEFF Research Database (Denmark)

    Jung, Nikolai H; Delvendahl, Igor; Pechmann, Astrid;

    2012-01-01

    Transcranial magnetic stimulation (TMS) commonly uses so-called monophasic pulses where the initial rapidly changing current flow is followed by a critically dampened return current. It has been shown that a monophasic TMS pulse preferentially excites different cortical circuits in the human motor...

  12. Receiver Signal to Noise Ratios for IPDA Lidars Using Sine-wave and Pulsed Laser Modulation and Direct Detections

    Science.gov (United States)

    Sun, Xiaoli; Abshire, James B.

    2011-01-01

    seeder lasers, one on-line and one offline that are intensity modulated by two different frequency sine-waves signals before being amplified by a common laser amplifier. The receiver uses narrowband amplitude demodulation, or lock-in, Signal processing at the given laser modulation frequencies [3,4]. The laser transmitter operates in a quasi CW mode with the peak power equal to twice the average power. The on-line and off-line lasers can be transmitted at the same time without interference. Another direct detection technique uses a low duty cycle pulsed laser modulation [5,6] with the laser wavelengths alternating between on-line and off-line on successive pulses. The receiver uses time resolved detection and can also provide simultaneous target range measurement. With a lower laser duty cycle it requires a much higher peak laser power for the same average power.

  13. Transformation of the frequency-modulated continuous-wave field into a train of short pulses by resonant filters

    CERN Document Server

    Shakhmuratov, R N

    2016-01-01

    The resonant filtering method transforming frequency modulated radiation field into a train of short pulses is proposed to apply in optical domain. Effective frequency modulation can be achieved by electro-optic modulator or by resonant frequency modulation of the filter with a narrow absorption line. Due to frequency modulation narrow-spectrum CW radiation field is seen by the resonant filter as a comb of equidistant spectral components separated by the modulation frequency. Tuning narrow-bandwidth filter in resonance with $n$-th spectral component of the comb transforms the radiation field into bunches of pulses with $n$ pulses in each bunch. The transformation is explained by the interference of the coherently scattered resonant component of the field with the whole comb. Constructive interference results in formation of pulses, while destructive interference is seen as dark windows between pulses. It is found that the optimal thickness of the resonant filter is several orders of magnitude smaller than the...

  14. A two-dimensional analysis of the sensitivity of a pulse first break to wave speed contrast on a scale below the resolution length of ray tomography.

    Science.gov (United States)

    Willey, Carson L; Simonetti, Francesco

    2016-06-01

    Mapping the speed of mechanical waves traveling inside a medium is a topic of great interest across many fields from geoscience to medical diagnostics. Much work has been done to characterize the fidelity with which the geometrical features of the medium can be reconstructed and multiple resolution criteria have been proposed depending on the wave-matter interaction model used to decode the wave speed map from scattering measurements. However, these criteria do not define the accuracy with which the wave speed values can be reconstructed. Using two-dimensional simulations, it is shown that the first-arrival traveltime predicted by ray theory can be an accurate representation of the arrival of a pulse first break even in the presence of diffraction and other phenomena that are not accounted for by ray theory. As a result, ray-based tomographic inversions can yield accurate wave speed estimations also when the size of a sound speed anomaly is smaller than the resolution length of the inversion method provided that traveltimes are estimated from the signal first break. This increased sensitivity however renders the inversion more susceptible to noise since the amplitude of the signal around the first break is typically low especially when three-dimensional anomalies are considered. PMID:27369139

  15. Backward-Propagating MeV Electrons in Ultra-Intense Laser Interactions: Standing Wave Acceleration and Coupling to the Reflected Laser Pulse

    CERN Document Server

    Orban, Chris; Chowdhury, Enam D; Nees, John A; Frische, Kyle; Roquemore, W Melvyn

    2014-01-01

    Laser-accelerated electron beams have been created at a kHz repetition rate from the reflection of intense ($\\sim10^{18}$ W/cm$^2$), 30 fs laser pulses focused on a continuous water-jet in an experiment at the Air Force Research Laboratory. This paper investigates Particle-In-Cell (PIC) simulations of the laser-target interaction to identify the physical mechanisms of electron acceleration in this experiment. We find that the standing-wave pattern created by the overlap of the incident and reflected laser is particularly important because this standing wave "injects" electrons into the reflected laser pulse where the electrons are further accelerated. We identify two regimes of standing wave acceleration: a highly relativistic case ($a_0~\\geq~1$), and a moderately relativistic case ($a_0~\\sim~0.5$) which operates over a larger fraction of the laser period. Previous work by other groups investigated the highly relativistic case for its usefulness in launching electrons in the forward direction. We extend this ...

  16. Backward-propagating MeV electrons in ultra-intense laser interactions: Standing wave acceleration and coupling to the reflected laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Orban, Chris, E-mail: orban@physics.osu.edu; Feister, Scott [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Morrison, John T. [National Research Council, Washington, DC 20001 (United States); Intense Energy Solutions, LLC, Plain City, Ohio 43064 (United States); Chowdhury, Enam A. [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Center for Ultra-Fast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Nees, John A. [Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Intense Energy Solutions, LLC, Plain City, Ohio 43064 (United States); Frische, Kyle [Innovative Scientific Solutions, Inc., Dayton, Ohio 45459 (United States); Roquemore, W. M. [Air Force Research Laboratory, Dayton, Ohio 45433 (United States)

    2015-02-15

    Laser-accelerated electron beams have been created at a kHz repetition rate from the reflection of intense (∼10{sup 18 }W/cm{sup 2}), ∼40 fs laser pulses focused on a continuous water-jet in an experiment at the Air Force Research Laboratory. This paper investigates Particle-in-Cell simulations of the laser-target interaction to identify the physical mechanisms of electron acceleration in this experiment. We find that the standing-wave pattern created by the overlap of the incident and reflected laser is particularly important because this standing wave can “inject” electrons into the reflected laser pulse where the electrons are further accelerated. We identify two regimes of standing wave acceleration: a highly relativistic case (a{sub 0} ≥ 1), and a moderately relativistic case (a{sub 0} ∼ 0.5) which operates over a larger fraction of the laser period. In previous studies, other groups have investigated the highly relativistic case for its usefulness in launching electrons in the forward direction. We extend this by investigating electron acceleration in the specular (back reflection) direction and over a wide range of intensities (10{sup 17}–10{sup 19 }W cm{sup −2})

  17. 辐射式核电磁脉冲模拟器快沿脉冲源研制%Development of Fast-Rising Pulse Source for Radiating-Wave Nuclear Electromagnetic Pulse Simulator

    Institute of Scientific and Technical Information of China (English)

    王赟; 范丽思; 成伟; 王民全; 刘朝阳

    2015-01-01

    根据辐射式核电磁脉冲模拟器对脉冲源的设计要求,研制一种由 Marx发生器和锐化装置构成的快沿脉冲源.Marx发生器为双边充电回路,由最大值高压无感电容器、电磁铁机械运动轨道触发开关、气体火花间隙开关及电阻等构成;锐化装置由分布参数同轴锐化电容和自击穿火花间隙锐化开关构成.对快沿脉冲源充放电等效回路进行Pspice模拟仿真,并通过试验测得实际的模拟器辐射场波形,结果表明:实测波形与仿真波形一致性较好,辐射式模拟器在距天线口径面3 m位置处产生上升时间小于5 ns、脉宽300多纳秒、峰值场强大于50 kV/m 的双指数脉冲场.实际研制的快沿脉冲源基本上满足了设计指标要求,为下一步改进优化辐射式模拟器奠定了基础.%According to the design requirement of pulse source used by the radiating-wave nuclear electromagnetic pulse (NEMP)simulator,a fast rising pulse source which consists of a Marx generator and sharpening equipment was developed.The Marx generator is bipolar charged and composed of the maximum high voltage non-inductive capacitor, electromagnet mechanical movement track trigger switch,gas spark gap switch and resistors,etc.Sharpening equipment is composed of sharpening coaxial capacitance with distributional parameters and self-breakdown spark gap switch.The Pspice simulation was carried out on the equivalent circuit of fast rising pulse source and the radiating waveform of simulator was measured through experiments.The results show that the measured waveform is similar to the simulated waveform.The radiating-wave nuclear electromagnetic pulse simulator can generate the exponential pulse field at three meters away from the aperture plane of antenna with the rising time less than 5 ns,pulse width more than 300 ns and peak value of field strength greater than 50 kV/m.The developed fast rising pulse source basically satisfies the

  18. Pulsed versus continuous wave low-level light therapy on osteoarticular signs and symptoms in limited scleroderma (CREST syndrome): a case report

    Science.gov (United States)

    Barolet, Daniel

    2014-11-01

    Limited cutaneous systemic sclerosis (lcSSc) was formerly known as CREST syndrome in reference to the associated clinical features: calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangiectasias. The transforming growth factor beta has been identified as a major player in the pathogenic process, where low-level light therapy (LLLT) has been shown to modulate this cytokine superfamily. This case study was conducted to assess the efficacy of 940 nm using millisecond pulsing and continuous wave (CW) modes on osteoarticular signs and symptoms associated with lcSSc. The patient was treated two to three times a week for 13 weeks using a sequential pulsing mode on one elbow and a CW mode on the other. Efficacy assessments included inflammation, symptoms, pain, health scales, patient satisfaction, clinical global impression, and adverse effects monitoring. Considerable functional and morphologic improvements were observed after LLLT, with the best results seen with the pulsing mode. No adverse effects were noted. Pulsed LLLT represents a treatment alternative for osteoarticular signs and symptoms in limited scleroderma (CREST syndrome).

  19. Comment on "Reconstructing surface wave profiles from reflected acoustic pulses" [J. Acoust. Soc. Am. 133(5), 2597-2611 (2013)].

    Science.gov (United States)

    Choo, Youngmin; Song, H C

    2016-05-01

    A computationally efficient, time-domain Helmholtz-Kirchhoff (H-K) integral was derived and applied to reconstructing surface wave profiles from reflected acoustic pulses [Walstead and Deane, J. Acoust. Soc. Am. 133, 2597-2611 (2013)]. However, the final form of the integral equation incorporating a stationary phase approximation contained a complex phase term exp(iπ/4), which cannot be treated as a simple time delay. In this work, a real time-domain H-K integral is presented that includes an additional Hilbert transform of the time-derivative of the transmitted pulse. Numerical simulation with a sinusoidal surface shows good agreement between the real time-domain formulation and exact H-K integral, while achieving a significant improvement in computational speed (e.g., 2 orders of magnitude). PMID:27250135

  20. Wave

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo

    2008-01-01

    Estimates for the amount of potential wave energy in the world range from 1-10 TW. The World Energy Council estimates that a potential 2TW of energy is available from the world’s oceans, which is the equivalent of twice the world’s electricity production. Whilst the recoverable resource is many...... times smaller it remains very high. For example, whilst there is enough potential wave power off the UK to supply the electricity demands several times over, the economically recoverable resource for the UK is estimated at 25% of current demand; a lot less, but a very substantial amount nonetheless....

  1. Bandwidth and repetition rate programmable Nyquist sinc-shaped pulse train source based on intensity modulators and four-wave mixing.

    Science.gov (United States)

    Cordette, S; Vedadi, A; Shoaie, M A; Brès, C-S

    2014-12-01

    We propose and experimentally demonstrate an all-optical Nyquist sinc-shaped pulse train source based on intensity modulation and four-wave mixing. The proposed scheme allows for the tunability of the bandwidth and the full flexibility of the repetition rate in the limit of the electronic bandwidth of the modulators used through the flexible synthesis of rectangular frequency combs. Bandwidth up to 360 GHz at 40 GHz rate and up to 45 frequency lines at 5 GHz rate are demonstrated with 40 GHz modulators.

  2. Fabrication, optimization, and characterization of monolithic semiconductor mode-locked lasers and colliding, pulse mode-locked lasers at millimeter-wave frequencies

    Science.gov (United States)

    Passerini, Marco; Sorel, Marc; Laybourn, Peter J.; Giuliani, Guido; Donati, Silvano

    2004-09-01

    This work reports on the fabrication, optimisation and characterisation of monolithic mode-locked lasers (MLLs) and colliding-pulse mode-locked (CPM) lasers with repetition rate in the range 10-60 GHz. The devices consist of double section split-contact ridge waveguide lasers fabricated in GaAs/AlGaAs double quantum well (DQW) material. For CPM devices, the saturable absorber section was fabricated with a coplanar ground-signal-ground (G-S-G) pad structure. The optimum saturable absorber size for efficient mode-locking is found experimentally. The fabricated devices are characterised in terms of operating regimes (Continuous Wave, Self-Pulsation, Mode-Locking) and the mode-locking signals were observed in the frequency domain using an external fast photodiode. In the case of CPM devices a mm-wave signal could also be extracted directly from the saturable absorber section of the laser using a microwave probe.

  3. High frame rate and high line density ultrasound imaging for local pulse wave velocity estimation using motion matching: A feasibility study on vessel phantoms.

    Science.gov (United States)

    Li, Fubing; He, Qiong; Huang, Chengwu; Liu, Ke; Shao, Jinhua; Luo, Jianwen

    2016-04-01

    Pulse wave imaging (PWI) is an ultrasound-based method to visualize the propagation of pulse wave and to quantitatively estimate regional pulse wave velocity (PWV) of the arteries within the imaging field of view (FOV). To guarantee the reliability of PWV measurement, high frame rate imaging is required, which can be achieved by reducing the line density of ultrasound imaging or transmitting plane wave at the expense of spatial resolution and/or signal-to-noise ratio (SNR). In this study, a composite, full-view imaging method using motion matching was proposed with both high temporal and spatial resolution. Ultrasound radiofrequency (RF) data of 4 sub-sectors, each with 34 beams, including a common beam, were acquired successively to achieve a frame rate of ∼507 Hz at an imaging depth of 35 mm. The acceleration profiles of the vessel wall estimated from the common beam were used to reconstruct the full-view (38-mm width, 128-beam) image sequence. The feasibility of mapping local PWV variation along the artery using PWI technique was preliminarily validated on both homogeneous and inhomogeneous polyvinyl alcohol (PVA) cryogel vessel phantoms. Regional PWVs for the three homogeneous phantoms measured by the proposed method were in accordance with the sparse imaging method (38-mm width, 32-beam) and plane wave imaging method. Local PWV was estimated using the above-mentioned three methods on 3 inhomogeneous phantoms, and good agreement was obtained in both the softer (1.91±0.24 m/s, 1.97±0.27 m/s and 1.78±0.28 m/s) and the stiffer region (4.17±0.46 m/s, 3.99±0.53 m/s and 4.27±0.49 m/s) of the phantoms. In addition to the improved spatial resolution, higher precision of local PWV estimation in low SNR circumstances was also obtained by the proposed method as compared with the sparse imaging method. The proposed method might be helpful in disease detections through mapping the local PWV of the vascular wall. PMID:26773791

  4. Pulse Waves in the Lower Extremities as a Diagnostic Tool of Peripheral Arterial Disease and Predictor of Mortality in Elderly Chinese.

    Science.gov (United States)

    Sheng, Chang-Sheng; Li, Yan; Huang, Qi-Fang; Kang, Yuan-Yuan; Li, Fei-Ka; Wang, Ji-Guang

    2016-03-01

    Patients with peripheral arterial disease may have elongated upstroke time in pulse waves in the lower extremities. We investigated upstroke time as a diagnostic tool of peripheral arterial disease and predictor of mortality in an elderly (≥60 years) Chinese population. We recorded pulse waves at the left and right ankles by pneumoplethysmography and calculated the percentage of upstroke time per cardiac cycle. Diagnostic accuracy was compared with the conventional ankle-brachial index method (n=4055) and computed tomographic angiography (34 lower extremities in 17 subjects). Upstroke time per cardiac cycle at baseline (mean±SD, 16.4%±3.1%) was significantly (Pperipheral arterial disease (upstroke time per cardiac cycle, ≥21.7%) in comparison with computed tomographic angiography. During 5.9 years (median) of follow-up, all-cause and cardiovascular deaths occurred in 366 and 183 subjects, respectively. In adjusted Cox regression analyses, an upstroke time per cardiac cycle ≥21.7% (n=219; 5.4%) significantly (Pperipheral arterial disease and predictor of mortality in the elderly.

  5. Consequences of the magnetic field, sonic and radiofrequency waves and intense pulsed light on the labeling of blood constituents with technetium-99m

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Patricia Froes; Costa, Iris do Ceu Clara; Brandao-Neto, Jose; Medeiros, Aldo da Cunha [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-graduacao em Ciencias da Saude; Santos-Filho, Sebastiao David; Adenilson de Souza da Fonseca; Bernardo-Filho, Mario [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Inst. de Biologia Roberto Alcantara Gomes. Lab. de Radiofarmacia Experimental; Ariel Ronzio, Oscar [Universidad de Buenos Aires (Argentina); Bonelli, Ludmila [Universidade Salgado de Oliveira, Belo Horizonte, MG (Brazil)

    2007-09-15

    Sources of magnetic field, radiofrequency and audible sonic waves and pulsed light have been used in physiotherapy to treat different disorders. In nuclear medicine, blood constituents(Bl-Co) are labeled with technetium-99m ({sup 99m}Tc) are used. This study evaluated the consequences of magnetic field, radiofrequency and audible sonic waves and intense pulsed light sources on the labeling of Bl-Co with {sup 99m}Tc. Blood from Wistar rats was exposed to the cited sources. The labeling of Bl-Co with {sup 99m}Tc was performed. Blood not exposed to the physical agents was used(controls). Data showed that the exposure to the different studied sources did not alter significantly (p>0.05) the labeling of Bl-Co. Although the results were obtained with animals, the data suggest that no alteration on examinations performed with Bl-Co labeled with {sup 99m}Tc after exposition to the cited agents. The biological consequences associated with these agents would be not capable to interfere with some properties of the Bl-Co. (author)

  6. Comparison of Thresholds for Pulmonary Capillary Hemorrhage Induced by Pulsed-wave and B-mode Ultrasound

    Science.gov (United States)

    Miller, Douglas L.; Dou, Chunyan; Raghavendran, Krishnan

    Pulsed ultrasound was found to induce pulmonary capillary hemorrhage (PCH) in mice about 25 years ago but remains a poorly understood risk factor for pulmonary diagnostic ultrasound. In early research using laboratory fixed beam ultrasound, thresholds for PCH had frequency variation from 1-4 MHz similar to the Mechanical Index. In recent research, thresholds for B mode diagnostic ultrasound from 1.5-12 MHz had little dependence on frequency. To compare the diagnostic ultrasound method to laboratory pulsed exposure, thresholds for fixed beam ultrasound were determined using comparable methods at 1.5 and 7.5 MHz. PCH thresholds were lower for simple fixed-beam pulse modes than for B mode and in approximate agreement with early research. However, for comparable timing parameters, PCH thresholds had little dependence on ultrasonic frequency. These findings suggest that the MI may not be directly useful as a dosimetric parameter for safety guidance in pulmonary ultrasound.

  7. Photoelectron circular dichroism in the multiphoton ionization by short laser pulses. I. Propagation of single-active-electron wave packets in chiral pseudo-potentials.

    Science.gov (United States)

    Artemyev, Anton N; Müller, Anne D; Hochstuhl, David; Demekhin, Philipp V

    2015-06-28

    A theoretical method to study the angle-resolved multiphoton ionization of polyatomic molecules is developed. It is based on the time-dependent formulation of the Single Center (TDSC) method and consists in the propagation of single-active-electron wave packets in the effective molecular potentials in the presence of intense laser pulses. For this purpose, the time-dependent Schrödinger equation for one electron, moving in a molecular field and interacting with an arbitrary laser pulse, is solved in spherical coordinates by an efficient numerical approach. As a test, the method is applied to the one- and two-photon ionizations of a model methane-like chiral system by circularly polarized short intense high-frequency laser pulses. Thereby, we analyze the photoelectron circular dichroism (PECD) in the momentum distribution. The considered model application illustrates the capability of the TDSC method to study multiphoton PECD in fixed-in-space and randomly oriented chiral molecules. PMID:26133408

  8. Development of a C-band 50 MW pulse klystron using traveling-wave-type output structure

    International Nuclear Information System (INIS)

    SuperKEKB requires a new klystron to increase its positron acceleration energy from 3.5 to 8.0 GeV. The C-Band 50 MW pulse Klystron (PV-5050K) has been under development at Mitsubishi Electric Corporation in collaboration with KEK for SuperKEKB. The first tube had been built and evaluated the performances, 50 MW output power and 48.5% power efficiency at pulse width of 2.0 μs and repetition rate of 50 pps. (author)

  9. Pressure and stress waves in a spallation neutron source mercury target generated by high-power proton pulses

    CERN Document Server

    Futakawa, M; Conrad, H; Stechemesser, H

    2000-01-01

    The international ASTE collaboration has performed a first series of measurements on a spallation neutron source target at the Alternating Gradient Synchrotron (AGS) in Brookhaven. The dynamic response of a liquid mercury target hit by high-power proton pulses of about 40 ns duration has been measured by a laser Doppler technique and compared with finite elements calculations using the ABAQUS code. It is shown that the calculation can describe the experimental results for at least the time interval up to 100 mu s after the pulse injection. Furthermore, it has been observed that piezoelectric pressure transducers cannot be applied in the high gamma-radiation field of a spallation target.

  10. Time-resolved observation of coherent excitonic nonlinear response with a table-top narrowband THz pulse wave

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, K. [Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Hirori, H., E-mail: hirori@icems.kyoto-u.ac.jp [Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Aoki, T. [CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Department of Applied Physics, School of Advanced Science and Technology, Waseda University, Shinjuku-ku, Tokyo 169-8555 (Japan); Wolpert, C.; Tamaya, T. [Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); Tanaka, K. [Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Sakyo-ku, Kyoto 606-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Mochizuki, T.; Kim, C.; Yoshita, M.; Akiyama, H. [Institute for Solid State Physics, University of Tokyo, and JST-CREST, Kashiwa, Chiba 277-8581 (Japan); Pfeiffer, L. N.; West, K. W. [Department of Electrical Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    2015-11-30

    By combining a tilted-pulse-intensity-front scheme using a LiNbO{sub 3} crystal and a chirped-pulse-beating method, we generated a narrowband intense terahertz (THz) pulse, which had a maximum electric field of more than 10 kV/cm at around 2 THz, a bandwidth of ∼50 GHz, and frequency tunability from 0.5 to 2 THz. By performing THz-pump and near-infrared-probe experiments on GaAs quantum wells, we observed that the resonant excitation of the intraexcitonic 1s-2p transition induces a clear and large Autler-Townes splitting. Our time-resolved measurements show that the splitting energy observed in the rising edge region of electric field is larger than in the constant region. This result implies that the splitting energy depends on the time-averaged THz field over the excitonic dephasing time rather than that at the instant of the exciton creation by a probe pulse.

  11. Time-resolved observation of coherent excitonic nonlinear response with a table-top narrowband THz pulse wave

    CERN Document Server

    Uchida, K; Aoki, T; Wolpert, C; Tamaya, T; Tanaka, K; Mochizuki, T; Kim, C; Yoshita, M; Akiyama, H; Pfeiffer, L N; West, K W

    2015-01-01

    By combining a tilted-pulse-intensity-front scheme using a LiNbO3 crystal and a chirped-pulse-beating method, we generated a narrowband intense terahertz (THz) pulse, which had a maximum electric field of more than 10 kV/cm at around 2 THz, a bandwidth of about 50 GHz,and frequency tunability from 0.5 to 2 THz. By performing THz-pump and near-infrared-probe experiments on GaAs quantum wells, we observed that the resonant excitation of the intraexcitonic 1s-2p transition induces a clear and large Autler-Townes splitting. Our time-resolved measurements show that the splitting energy observed in the rising edge region of electric field is larger than in the constant region. This result implies that the splitting energy depends on the time-averaged THz field over the excitonic dephasing time rather than that at the instant of the exciton creation by a probe pulse.

  12. Plasma levels of the arterial wall protein fibulin-1 are associated with carotid-femoral pulse wave velocity

    DEFF Research Database (Denmark)

    Laugesen, Esben; Høyem, Pernille; Christiansen, Jens Sandahl;

    2013-01-01

    -associated extracellular matrix protein, fibulin-1, was recently found in higher concentrations in the arterial wall and in plasma in patients with long duration type 2 diabetes. Furthermore, plasma fibulin-1 independently predicted total mortality and was associated with pulse pressure, an indirect measure of arterial...

  13. Pulse on Pulse

    DEFF Research Database (Denmark)

    Schmidt, Ulrik; Carlson, Merete

    2012-01-01

    Pulse on Pulse” investigates the relation between signifying processes and non-signifying material dynamism in the installation Pulse Room (2006-) by Mexican Canadian artist Rafael Lozano-Hemmer. In Pulse Room the sense of pulse is ambiguous. Biorhythms are transmitted from the pulsing energy...

  14. Inter-beat intervals of cardiac-cell aggregates during exposure to 2.45 GHz CW, pulsed, and square-wave-modulated microwaves.

    Science.gov (United States)

    Seaman, R L; DeHaan, R L

    1993-01-01

    Inter-beat intervals of aggregated cardiac cells from chicken embryos were studied during 190 s exposures to 2.45 GHz microwaves in an open-ended coaxial device. Averaged specific-absorption rates (SARs) and modulation conditions were 1.2-86.9 W/kg continuous-wave (CW), 1.2-12.2 W/kg pulse modulation (PW, duty cycle approximately 11%), and 12.0-43.5 W/kg square-wave modulation (duty cycle = 50%). The inter-beat interval decreased during microwave exposures at 42.0 W/kg and higher when CW or square-wave modulation was used, which is consistent with established effects of elevated temperatures. However, increases in the inter-beat interval during CW exposures at 1.2-12.2 W/kg, and decreases in the inter-beat interval after PW exposures at 8.4-12.2 W/kg, are not consistent with simple thermal effects. Analysis of variance indicated that SAR, modulation, and the modulation-SAR interaction were all significant factors in altering the inter-beat interval. The latter two factors indicated that the cardiac cells were affected by athermal as well as thermal effects of microwave exposure.

  15. Tunable error-free optical frequency conversion of a 4ps optical short pulse over 25 nm by four-wave mixing in a polarisation-maintaining optical fibre

    Science.gov (United States)

    Morioka, T.; Kawanishi, S.; Saruwatari, M.

    1994-05-01

    Error-free, tunable optical frequency conversion of a transform-limited 4.0 ps optical pulse signalis demonstrated at 6.3 Gbit/s using four-wave mixing in a polarization-maintaining optical fibre. The process generates 4.0-4.6 ps pulses over a 25nm range with time-bandwidth products of 0.31-0.43 and conversion power penalties of less than 1.5 dB.

  16. Elastic wave velocity inspection for rocks by pulse compression method%脉冲压缩方法检测岩石弹性波速度

    Institute of Scientific and Technical Information of China (English)

    李长征; 张碧星; 师芳芳

    2013-01-01

    On account of existing problems in rock elastic wave velocity inspecting,such as low signal to noise ratio(SNR),difficulty in reading the prime time of echo and inspecting large volume rock,pulse compression method is proposed.Linear frequency modulation (LFM) signal is mostly used as exciting source due to its remarkable properties,such as wide bandwidth,high energy and high SNR.While receiving terminal,echo signal is filtered by a matched filter,and the compression signal of high SNR is obtained.The wide time and band characteristics of LFM signal are introduced.In addition,the pulse compression principle and digital implementation process are also analyzed.The influence of the bandwidth of transducer on exciting signal is studied; elastic wave velocity of several rocks is inspected with a conventional method and pulse compression method.The wave velocity differences of two testing methods show a limited error.The detailed implementation and calculating process of pulse compression inspecting method are also described.The advantages and prospects of the method are analyzed.Results show that pulse compression method can be applied to inspect the elastic wave velocity in rock and access engineering quality.%针对岩石弹性波速度检测信噪比低、回波信号初至时间不易判读,以及较长岩石(或混凝土)超声检测难以穿透问题,提出用脉冲压缩方法检测弹性波速度.该方法与超声脉冲法检测的不同之处是在发射端采用编码信号激励,在接收端进行匹配滤波,得到高信噪比的压缩信号.介绍线性调频信号的宽时宽带特性,分析了脉冲压缩的基本原理和数字实现过程.试验研究了换能器带宽对激发信号的影响.用常规的单脉冲法和脉冲压缩方法检测了多个岩样的弹性波速度,试验结果表明,两种检测结果差异较小.给出了脉冲压缩方法用于岩石弹性波速度检测的具体步骤和计算过程.综合分析,脉冲压缩方法检

  17. Effects of salt substitute on pulse wave analysis among individuals at high cardiovascular risk in rural China: a randomized controlled trial.

    Science.gov (United States)

    Hu, Jihong; Jiang, Xiongjing; Li, Nicole; Yu, Xuequn; Perkovic, Vlado; Chen, Bailing; Zhao, Liancheng; Neal, Bruce; Wu, Yangfeng

    2009-04-01

    Reduced-sodium, increased-potassium salt substitutes lower blood pressure but may also have direct effects on vascular structure and arterial function. This study aimed to test the effects of long-term salt substitution on indices of these outcomes. The China Salt Substitute Study was a randomized, controlled trial designed to establish the effects of salt substitute (65% sodium chloride, 25% potassium chloride, 10% magnesium sulfate) compared with regular salt (100% sodium chloride) on blood pressure among 600 high-risk individuals living in six rural areas in northern China over a 12-month intervention period. Data on central aortic blood pressure, aortic pressure augmentation (AUG), augmentation index (AIx), the differences of the peak of first and baseline waves (P(1)-P(0)) and pulse wave reflection time (RT) were collected at randomization and at the completion of follow-up in 187 participants using the Sphygmocor pulse wave analysis system. Mean baseline blood pressure was 150.1/91.4 mm Hg, mean age was 58.4 years, 41% were male and three quarters had a history of vascular disease. After 12 months of intervention, there were significant net reductions in peripheral (7.4 mm Hg, P=0.009) and central (6.9 mm Hg, P=0.011) systolic blood pressure levels and central pulse pressure (4.5 mm Hg, P=0.012) and correspondingly there was a significant net reduction in P(1)-P(0) (3.0 mm Hg, P=0.007), borderline significant net reduction in AUG (1.5 mm Hg, P=0.074) and significant net increase in RT (2.59 ms, P=0.001). There were no detectable reductions in peripheral (2.8 mm Hg, P=0.14) or central (2.4 mm Hg, P=0.13) diastolic blood pressure levels or AIx (0.06%, P=0.96). In conclusion, over the 12-month study period the salt substitute significantly reduced not only peripheral and central systolic blood pressure but also reduced arterial stiffness.

  18. Thermal decomposition of 1-chloropropane behind the reflected shock waves in the temperature range of 1015-1220 K: Single pulse shock tube and computational studies

    Indian Academy of Sciences (India)

    G Sudhakar; B Rajakumar

    2014-07-01

    The thermal decomposition of 1-chloropropane in argon was studied behind reflected shock waves in a single pulse shock tube over the temperature range of 1015-1220 K. The reaction mainly goes through unimolecular elimination of HCl. The major products observed in the decomposition are propylene and ethylene, while the minor products identified are methane and propane. The rate constant for HCl elimination in the studied temperature range is estimated to be k(1015-1220 K) = 1.63 × 1013exp(-(60.1 ± 1.0) kcal mol-1/RT) s-1. The DFT calculations were carried out to identify the transition state(s) for the major reaction channel; and rate coefficient for this reaction is obtained to be k(800-1500 K) = 5.01 × 1014exp(-(58.8) kcal mol-1/RT) s-1. The results are compared with the experimental findings.

  19. Permanent fixing or reversible trapping and release of DNA micropatterns on a gold nanostructure using continuous-wave or femtosecond-pulsed near-infrared laser light.

    Science.gov (United States)

    Shoji, Tatsuya; Saitoh, Junki; Kitamura, Noboru; Nagasawa, Fumika; Murakoshi, Kei; Yamauchi, Hiroaki; Ito, Syoji; Miyasaka, Hiroshi; Ishihara, Hajime; Tsuboi, Yasuyuki

    2013-05-01

    The use of localized surface plasmons (LSPs) for highly sensitive biosensors has already been investigated, and they are currently being applied for the optical manipulation of small nanoparticles. The objective of this work was the optical trapping of λ-DNA on a metallic nanostructure with femtosecond-pulsed (fs) laser irradiation. Continuous-wave laser irradiation, which is generally used for plasmon excitation, not only increased the electromagnetic field intensity but also generated heat around the nanostructure, causing the DNA to become permanently fixed on the plasmonic substrate. Using fs laser irradiation, on the other hand, the reversible trapping and release of the DNA was achieved by switching the fs laser irradiation on and off. This trap-and-release behavior was clearly observed using a fluorescence microscope. This technique can also be used to manipulate other biomolecules such as nucleic acids, proteins, and polysaccharides and will prove to be a useful tool in the fabrication of biosensors. PMID:23586869

  20. Investigation of continuous wave and pulsed laser performance based on Nd3+:Gd0.6Y1.4SiO5 crystal

    Science.gov (United States)

    Feng, Chao; Liu, Zhaojun; Cong, Zhenhua; Shen, Hongbin; Li, Yongfu; Wang, Qingpu; Fang, Jiaxiong; Xu, Xiaodong; Xu, Jun; Zhang, Xingyu

    2015-12-01

    We systematically investigated a laser diode (LD) pumped Nd:GYSO (Nd3+:Gd0.6Y1.4SiO5) laser. The output power of the continuous wave laser was as high as 3.5 W with a slope efficiency of 31.8%. In the Q-switched operation; the laser exhibited dual-wavelengths output (1073.6 nm and 1074.7 nm) synchronously with a Cr4+:YAG as the saturable absorber (SA). Additionally, a passively mode-locked laser was demonstrated using a semiconductor SA mirror with a maximum average output power of 510 mW at a central wavelength of 1074 nm, while the pulse width of the laser was as short as 5 ps. Our experiment proved that the Nd:GYSO mixed crystal was a promising material for a solid-state laser.

  1. All-fiber quasi-continuous wave supercontinuum generation in single-mode high-nonlinear fiber pumped by submicrosecond pulse with low peak power.

    Science.gov (United States)

    Gao, Weiqing; Liao, Meisong; Yan, Xin; Suzuki, Takenobu; Ohishi, Yasutake

    2012-05-01

    We demonstrate quasi-continuous wave supercontinuum generation in a single-mode high-nonlinear fiber (HNLF) in 1.55 μm band, which is pumped by the amplified passively Q-switched submicrosecond pulse. The pump wavelength is in the normal dispersion region of HNLF and near to the zero-dispersion wavelength. The broad SC spectral range from 1200 to 2260 nm is obtained with the low pump peak power of 17.8 W. The 20 dB bandwidth of 922 nm from 1285 to 2207 nm is obtained with the assumption that the peak near 1560 nm is filtered. The spectrum density for the 20 dB bandwidth is from -27.5 to -7.5 dbm/nm. PMID:22614410

  2. Ethnic Differences in and Childhood Influences on Early Adult Pulse Wave Velocity: The Determinants of Adolescent, Now Young Adult, Social Wellbeing, and Health Longitudinal Study.

    Science.gov (United States)

    Cruickshank, J Kennedy; Silva, Maria J; Molaodi, Oarabile R; Enayat, Zinat E; Cassidy, Aidan; Karamanos, Alexis; Read, Ursula M; Faconti, Luca; Dall, Philippa; Stansfield, Ben; Harding, Seeromanie

    2016-06-01

    Early determinants of aortic stiffness as pulse wave velocity are poorly understood. We tested how factors measured twice previously in childhood in a multiethnic cohort study, particularly body mass, blood pressure, and objectively assessed physical activity affected aortic stiffness in young adults. Of 6643 London children, aged 11 to 13 years, from 51 schools in samples stratified by 6 ethnic groups with different cardiovascular risk, 4785 (72%) were seen again at aged 14 to 16 years. In 2013, 666 (97% of invited) took part in a young adult (21-23 years) pilot follow-up. With psychosocial and anthropometric measures, aortic stiffness and blood pressure were recorded via an upper arm calibrated Arteriograph device. In a subsample (n=334), physical activity was measured >5 days via the ActivPal. Unadjusted pulse wave velocities in black Caribbean and white UK young men were similar (mean±SD 7.9±0.3 versus 7.6±0.4 m/s) and lower in other groups at similar systolic pressures (120 mm Hg) and body mass (24.6 kg/m(2)). In fully adjusted regression models, independent of pressure effects, black Caribbean (higher body mass/waists), black African, and Indian young women had lower stiffness (by 0.5-0.8; 95% confidence interval, 0.1-1.1 m/s) than did white British women (6.9±0.2 m/s). Values were separately increased by age, pressure, powerful impacts from waist/height, time spent sedentary, and a reported racism effect (+0.3 m/s). Time walking at >100 steps/min was associated with reduced stiffness (Pracism) independently increase arterial stiffness, effects likely to increase with age. PMID:27141061

  3. THE DIAGNOSTIC VALUE OF PULSED WAVE TISSUE DOPPLER IMAGING IN ASYMPTOMATIC BETA- THALASSEMIA MAJOR CHILDREN AND YOUNG ADULTS ; RELATION TO CHEMICAL BIOMARKERS OF LEFT VENTRICULAR FUNCTION AND IRON OVERLOAD .

    Directory of Open Access Journals (Sweden)

    Seham Ragab

    2015-08-01

    Full Text Available Background: Cardiac iron toxicity is the leading cause of death among  β-halassaemia major (TM  patients.  Once  heart failure becomes overt , it will be  difficult to reverse . Objectives: To investigate non overt cardiac dysfunctions  in TM patients using  pulsed wave Tissue Doppler  Imaging (TD I and its relation to the iron overload and brain natruritic peptide (BNP. Methods: Thorough  clinical , conventional echo and  pulsed  wave TDI  parameters were compared between  asymtomatic 25 β-TM  patients  and 20 age and gender matched individuals. Serum ferritin and plasma BNP  levels were assayed by  ELISA .  Results: TM patients had significant higher mitral inflow early diastolic (E wave and  non significant other conventional echo  parameters. Pulsed wave TDI revealed systolic and diastolic dysfunctions in the form of significant higher  isovolumetric contraction time (ICT , ejection time ( E T and  isovolumetric relaxation time (IRT with significantly lower  mitral annulus  early diastolic velocity E` (12.07 ±2.06 vs 15.04±2.65 ,P= 0.003  in patients compared to  controls. Plasma BNP was higher in patients compared to the controls.  Plasma BNP and serum ferritin had significant correlation with each other and with pulsed wave conventional and TDI indices of systolic and diastolic functions.  Patients with E/E` ≥ 8 had  significant higher  serum ferritin  and plasma BNP levels compared to those with E/E` ratio < 8 without difference in Hb levels .Conclusion:  Pulsed wave TDI  is an  important diagnostic tool for latent cardiac dysfunction in iron loaded TM patients and is related to iron overload and BNP .

  4. Regional in vivo transit time measurements of aortic pulse wave velocity in mice with high-field CMR at 17.6 Tesla

    Directory of Open Access Journals (Sweden)

    Rommel Eberhard

    2010-12-01

    Full Text Available Abstract Background Transgenic mouse models are increasingly used to study the pathophysiology of human cardiovascular diseases. The aortic pulse wave velocity (PWV is an indirect measure for vascular stiffness and a marker for cardiovascular risk. Results This study presents a cardiovascular magnetic resonance (CMR transit time (TT method that allows the determination of the PWV in the descending murine aorta by analyzing blood flow waveforms. Systolic flow pulses were recorded with a temporal resolution of 1 ms applying phase velocity encoding. In a first step, the CMR method was validated by pressure waveform measurements on a pulsatile elastic vessel phantom. In a second step, the CMR method was applied to measure PWVs in a group of five eight-month-old apolipoprotein E deficient (ApoE(-/- mice and an age matched group of four C57Bl/6J mice. The ApoE(-/- group had a higher mean PWV (PWV = 3.0 ± 0.6 m/s than the C57Bl/6J group (PWV = 2.4 ± 0.4 m/s. The difference was statistically significant (p = 0.014. Conclusions The findings of this study demonstrate that high field CMR is applicable to non-invasively determine and distinguish PWVs in the arterial system of healthy and diseased groups of mice.

  5. High harmonic generation in H$_{2}^{+}$ and HD+ by intense femtosecond laser pulses: A wave packet approach with nonadiabatic interaction in HD+

    Indian Academy of Sciences (India)

    Farzana Sharmin; Samir Saha; S S Bhattacharyya

    2013-06-01

    We have theoretically investigated the high harmonic generation (HHG) spectra of H$_{2}^{+}$ and HD+ using a time-dependent wave packet approach for the nuclear motion with pulsed lasers of peak intensities (0) of 3.5 × 1014 and 4.5 × 1014 W/cm2, wavelengths (L) of 800 and 1064 nm, and pulse durations () of 40 and 50 fs, for initial vibrational levels 0 = 0 and 1. We have argued that for these conditions the harmonic generation due to the transitions in the electronic continuum by tunnelling or multiphoton ionization will not be important. Thus, the characteristic features of HHG spectra in our model arise only due to the nuclear motions on the two lowest field-coupled electronic states between which both interelectronic and intraelectronic (due to intrinsic dipole moments, for HD+) radiative transitions can take place. For HD+, the effect of nonadiabatic (NA) interaction between the two lowest Born–Oppenheimer (BO) electronic states has been taken into account and comparison has been made with the HHG spectra of HD+ obtained in the BO approximation. Even harmonics and a second plateau in the HHG spectra of HD+ with the NA interaction and hyper-Raman lines in the spectra of both H$_{2}^{+}$ and HD+ for 0 = 1 have been observed for higher value of 0 or L. Our calculations indicate reasonable efficiencies of harmonic generation even without involving the electronic continuum.

  6. Rigorous 2D Model for Study of Pulsed and Monochromatic Waves Propagation Near the Earth’s Surface

    OpenAIRE

    Sautbekov, Seil S.; Yuriy K. Sirenko; Nataliya P. Yashina; Aleksey A. Vertiy

    2014-01-01

    A model problem considered in the paper allows solving rather complex 2D problems of the electromagnetic wave propagation with a required accuracy using conventional personal computers. The problems are of great importance for the theory and practical applications. The association of FDTD schemes with exact absorbing conditions makes up the basis for constructing models of the kind. This approach reduces the original open initial boundary value problems to the equivalent closed problems which...

  7. AB067. Future ED therapy: low-energy shock wave therapy and low-intensity pulsed ultrasound therapy

    OpenAIRE

    Xin, Zhong-Cheng

    2015-01-01

    Current treatments for erectile dysfunction (ED) such as phosphodiesterase type 5 inhibitors (PDE5Is) and intracavernosal injections (ICI) therapy, such a symptom therapy used as on demanded before sexual intercourse, the clinical efficacy reached to 80%, with mild side effects, however, such a symptom therapy could not restore pathological changes in the penis. Low-energy shock wave therapy (LESWT) has been developed for treating ED, and clinical studies have shown that LESWT has the potenti...

  8. Arterial Stiffness, Central Pulsatile Hemodynamic Load, and Orthostatic Hypotension.

    Science.gov (United States)

    Liu, Kai; Wang, Si; Wan, Shixi; Zhou, Yufei; Pan, Pei; Wen, Bo; Zhang, Xin; Liao, Hang; Shi, Di; Shi, Rufeng; Chen, Xiaoping; Jangala, Tulasiram

    2016-07-01

    The association between central pulsatile hemodynamic load, arterial stiffness, and orthostatic hypotension (OH) is unclear. The authors recruited 1099 participants from the community. Questionnaire, physical examination, and laboratory tests were performed. To assess the correlation between central pulsatile hemodynamic load, arterial stiffness, and OH, multiple logistic regression analysis was performed, and the discriminatory power was assessed by the area under the receiver operating curve. The prevalence of OH in this population was 5.6%. After adjusting for potential confounders, brachial-ankle pulse wave velocity (BaPWV) was significantly and positively correlated with OH in both the hypertension and nonhypertension groups (all Ppower than CSBP in both subgroups. BaPWV appears to be a better indicator of OH than CSBP in routine clinical practice. PMID:26543017

  9. Serum ferritin levels are associated with arterial stiffness in healthy Korean adults.

    Science.gov (United States)

    Ha, Ji Yoon; Kim, Min Kyung; Kang, Shinae; Nam, Ji Sun; Ahn, Chul Woo; Kim, Kyung Rae; Park, Jong Suk

    2016-08-01

    Although an association between serum ferritin and atherosclerosis has been suggested, limited epidemiologic data are available regarding the association between ferritin and arterial stiffness in healthy adults. A total of 2932 healthy subjects were enrolled in this study. Anthropometric and biochemical profiles including ferritin were measured. The arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV). Serum ferritin levels were classified into quartiles and baPWV values gradually increased with each ferritin quartile. Multiple regression analysis showed that ferritin levels were independently correlated with baPWV. After adjusting for multiple risk factors, as compared with the lowest quartile, the odds ratios for high baPWV (>75(th) percentile) were 1.15 (0.84-1.56), 1.37 (0.97-1.73), and 1.46 (1.29-2.17) among men (p for trend Korean adults. PMID:26926288

  10. Electrical stimulation vs. pulsed and continuous-wave optical stimulation of the rat prostate cavernous nerves, in vivo

    Science.gov (United States)

    Perkins, William C.; Lagoda, Gwen A.; Burnett, Arthur; Fried, Nathaniel M.

    2015-07-01

    Identification and preservation of the cavernous nerves (CNs) during prostate cancer surgery is critical for post-operative sexual function. Electrical nerve stimulation (ENS) mapping has previously been tested as an intraoperative tool for CN identification, but was found to be unreliable. ENS is limited by the need for electrode-tissue contact, poor spatial precision from electrical current spreading, and stimulation artifacts interfering with detection. Alternatively, optical nerve stimulation (ONS) provides noncontact stimulation, improved spatial selectivity, and elimination of stimulation artifacts. This study compares ENS to pulsed/CW ONS to explore the ONS mechanism. A total of eighty stimulations were performed in 5 rats, in vivo. ENS (4 V, 5 ms, 10 Hz) was compared to ONS using a pulsed diode laser nerve stimulator (1873 nm, 5 ms, 10 Hz) or CW diode laser nerve stimulator (1455 nm). Intracavernous pressure (ICP) response and nerve compound action potentials (nCAPs) were measured. All three stimulation modes (ENS, ONS-CW, ONS-P) produced comparable ICP magnitudes. However, ENS demonstrated more rapid ICP response times and well defined nCAPs compared to unmeasurable nCAPs for ONS. Further experiments measuring single action potentials during ENS and ONS are warranted to further understand differences in the ENS and ONS mechanisms.

  11. Electroanalytical determination of donepezil HCl in tablets and human serum by differential pulse and osteryoung square wave voltammetry at a glassy carbon electrode.

    Science.gov (United States)

    Golcu, A; Ozkan, S A

    2006-09-01

    Donepezil hydrochloride (DNP) is used for the treatment of mild to moderate dementia of the Alzheimer's type. The voltammetric behavior of DNP was studied at a glassy carbon electrode using cyclic, linear sweep, differential pulse (DPV) and square-wave (OSWV) voltammetric techniques. DNP exhibited irreversible anodic waves within the pH range 1.80 and 9.00 in different supporting electrolytes. The peak was characterized as being irreversible and diffusion-controlled. The possible mechanism of the oxidation process is discussed. The current-concentration plot was rectilinear over the range from 1 x 10(-6) to 1 x 10(-4) M in Britton-Robinson buffer at pH 7.0 with a correlation coefficient between 0.997 and 0.999 in supporting electrolyte and human serum samples using the DPV and SWV techniques. The repeatability and reproducibility of the methods for both media (supporting electrolyte and serum sample) were determined. Precision and accuracy of the developed methods were demonstrated by recovery studies. The standard addition method was used for the recovery studies. No electroactive interferences were found in biological fluids from endogenous substances or additives present in tablets. The methods developed were successfully applied to the determination of DNP in tablets and in spiked human serum.

  12. Rigorous 2D Model for Study of Pulsed and Monochromatic Waves Propagation Near the Earth’s Surface

    Directory of Open Access Journals (Sweden)

    Seil S. Sautbekov

    2014-01-01

    Full Text Available A model problem considered in the paper allows solving rather complex 2D problems of the electromagnetic wave propagation with a required accuracy using conventional personal computers. The problems are of great importance for the theory and practical applications. The association of FDTD schemes with exact absorbing conditions makes up the basis for constructing models of the kind. This approach reduces the original open initial boundary value problems to the equivalent closed problems which can be solved numerically using the standard grid methods.

  13. Time-dependent wave packet approach to the pulse delay effect upon RbI photoelectron spectrum

    Institute of Scientific and Technical Information of China (English)

    LIU Chunhua; MENG Qingtian; ZHANG Qinggang

    2006-01-01

    The time-resolved photoelectron spectrum (TRPES) of Rbl molecule is simulated using the time-dependent wave-packet method. Both the normal three-photon ionization process and auto-ionization process are involved in the simulation. The calculated results show that the change of delay time will influence the shape of the photoelectron spectrum (PES), and the influence is substantially due to the existence of the crossing between excited states and the strong laser field which will change the position of relevant curves.

  14. Solitary wave in a Burridge-Knopoff model with slip-dependent friction as a clue to understanding the mechanism of the self-healing slip pulse in an earthquake rupture process

    Directory of Open Access Journals (Sweden)

    Z. L. Wu

    1998-01-01

    Full Text Available A one-dimensional Burridge-Knopoff spring-block model with slip-dependent friction was studied to explore the possibility of a solitary wave solution existing for the problem of earthquake faulting. The result may be used as an alternative case of the crack model (e.g., Madariaga and Cochard, 1996 and the spring-block model with velocity-dependent friction (e.g., Carlson and Langer, 1989 in the understanding of the mechanism of the self-healing slip pulse proposed by Heaton (1990. In general, the conditions for a solitary wave solution to exist are discussed by the trajectory in the phase space. By taking the first order approximation, it is demonstrated that a solitary wave solution exists in which the slip behaves as a propagating solitary wave with the propagation velocity less than that of an acoustic (seismic wave, and the source time function at each position remains the same. As an alternative approach other than numerical calculations, the analytical solution, although simple, sheds light on some of the properties of the self-healing slip pulse. From the solution it is seen that the width of the pulse depends on its propagation velocity and the friction, consistent with experience in physics. It is pointed out that the self-healing slip pulse may exist for a broad class of frictional constitutive laws which, to some extent, explains the fact that the self-healing slip pulse may be observed for a variety of earthquakes occurring within different seismogenic environments.

  15. ELF wave generation in the ionosphere using pulse modulated HF heating: initial tests of a technique for increasing ELF wave generation efficiency

    Directory of Open Access Journals (Sweden)

    R. Barr

    Full Text Available This paper describes the results of a preliminary study to determine the effective heating and cooling time constants of ionospheric currents in a simulated modulated HF heating, `beam painting' configuration. It has been found that even and odd harmonics of the fundamental ELF wave used to amplitude modulate the HF heater are sourced from different regions of the ionosphere which support significantly different heating and cooling time constants. The fundamental frequency and its odd harmonics are sourced in a region of the ionosphere where the heating and cooling time constants are about equal. The even harmonics on the other hand are sourced from regions of the ionosphere characterised by ratios of cooling to heating time constant greater than ten. It is thought that the even harmonics are sourced in the lower ionosphere (around 65 km where the currents are much smaller than at the higher altitudes around 78 km where the currents at the fundamental frequency and odd harmonics maximise.

    Key words. Electromagnetics (antennae · Ionosphere (active experiments · Radio science (non linear phenomena

  16. Nonlinear pulse compression

    OpenAIRE

    Grün, Alexander

    2014-01-01

    In this thesis I investigate two methods for generating ultrashort laser pulses in spectral regions which are ordinarily difficult to achieve by the existing techniques. These pulses are specially attractive in the study of ultrafast (few femtosecond) atomic and molecular dynamics. The first involves Optical Parametric Amplification (OPA) mediated by four-wave-mixing in gas and supports the generation of ultrashort pulses in the Near-InfraRed (NIR) to the Mid-InfraRed (MIR) spectral regio...

  17. Bramwell-Hill modeling for local aortic pulse wave velocity estimation: a validation study with velocity-encoded cardiovascular magnetic resonance and invasive pressure assessment

    Directory of Open Access Journals (Sweden)

    Westenberg Jos JM

    2012-01-01

    Full Text Available Abstract Background The Bramwell-Hill model describes the relation between vascular wall stiffness expressed in aortic distensibility and the pulse wave velocity (PWV, which is the propagation speed of the systolic pressure wave through the aorta. The main objective of this study was to test the validity of this model locally in the aorta by using PWV-assessments based on in-plane velocity-encoded cardiovascular magnetic resonance (CMR, with invasive pressure measurements serving as the gold standard. Methods Seventeen patients (14 male, 3 female, mean age ± standard deviation = 57 ± 9 years awaiting cardiac catheterization were prospectively included. During catheterization, intra-arterial pressure measurements were obtained in the aorta at multiple locations 5.8 cm apart. PWV was determined regionally over the aortic arch and locally in the proximal descending aorta. Subsequently, patients underwent a CMR examination to measure aortic PWV and aortic distention. Distensibility was determined locally from the aortic distension at the proximal descending aorta and the pulse pressure measured invasively during catheterization and non-invasively from brachial cuff-assessment. PWV was determined regionally in the aortic arch using through-plane and in-plane velocity-encoded CMR, and locally at the proximal descending aorta using in-plane velocity-encoded CMR. Validity of the Bramwell-Hill model was tested by evaluating associations between distensibility and PWV. Also, theoretical PWV was calculated from distensibility measurements and compared with pressure-assessed PWV. Results In-plane velocity-encoded CMR provides stronger correlation (p = 0.02 between CMR and pressure-assessed PWV than through-plane velocity-encoded CMR (r = 0.69 versus r = 0.26, with a non-significant mean error of 0.2 ± 1.6 m/s for in-plane versus a significant (p = 0.006 error of 1.3 ± 1.7 m/s for through-plane velocity-encoded CMR. The Bramwell-Hill model shows a

  18. Nanoshell-mediated targeted photothermal therapy of HER2 human breast cancer cells using pulsed and continuous wave lasers: an in vitro study.

    Science.gov (United States)

    Khosroshahi, Mohammad E; Hassannejad, Zahra; Firouzi, Masoumeh; Arshi, Ahmad R

    2015-09-01

    In this study, we report the apoptosis induction in HER2 overexpressed breast cancer cells using pulsed, continuous wave lasers and polyvinylpyrrolidone (PVP)-stabilized magneto-plasmonic nanoshells (PVP-MPNS) delivered by immunoliposomes. The immunoliposomes containing PVP-MPNS were fabricated and characterized. Heating efficiency of the synthesized nanostructures was calculated. The effect of functionalization on cellular uptake of nanoparticles was assessed using two cell lines of BT-474 and Calu-6. The best uptake result was achieved by functionalized liposome (MPNS-LAb) and BT-474. Also, the interaction of 514 nm argon (Ar) and Nd/YAG second harmonic 532-nm lasers with nanoparticles was investigated based on the temperature rise of the nanoshell suspension and the release value of 5(6)-carboxyfluorescein (CF) from CF/MPNS-loaded liposomes. The temperature increase of the suspensions after ten consecutive pulses of 532 nm and 5 min of irradiation by Ar laser were measured approximately 2 and 12 °C, respectively. The irradiation of CF/MPNS-loaded liposomes by Ar laser for 3 min resulted in 24.3 % release of CF, and in the case of 532 nm laser, the release was laser energy dependent. Furthermore, the comparison of CF release showed a higher efficiency for the Ar laser than by direct heating of nanoshell suspension using circulating water. The percentage of cell apoptosis after irradiation by Ar and 532 nm lasers were 44.6 and 42.6 %, respectively. The obtained results suggest that controlling the NP-laser interaction using optical properties of nanoshells and the laser parameters can be used to develop a new cancer therapy modality via targeted nanoshell and drug delivery.

  19. Consequences of the magnetic field, sonic and radiofrequency waves and intense pulsed light on the labeling of blood constituents with technetium-99m

    Directory of Open Access Journals (Sweden)

    Patricia Froes Meyer

    2007-09-01

    Full Text Available Sources of magnetic field, radiofrequency and audible sonic waves and pulsed light have been used in physiotherapy to treat different disorders. In nuclear medicine, blood constituents(Bl-Co are labeled with technetium-99m (99mTc are used. This study evaluated the consequences of magnetic field, radiofrequency and audible sonic waves and intense pulsed light sources on the labeling of Bl-Co with 99mTc. Blood from Wistar rats was exposed to the cited sources. The labeling of Bl-Co with 99mTc was performed. Blood not exposed to the physical agents was used(controls. Data showed that the exposure to the different studied sources did not alter significantly (p>0.05 the labeling of Bl-Co. Although the results were obtained with animals, the data suggest that no alteration on examinations performed with Bl-Co labeled with 99mTc after exposition to the cited agents. The biological consequences associated with these agents would be not capable to interfere with some properties of the Bl-Co.Fontes de campo magnético, ondas sonoras audíveis e de radiofreqüência e luz intensa pulsada são usadas para o tratamento de doenças. Constituintes sangüíneos(CS marcados com tecnécio-99m(99mTc são utilizados na medicina nuclear. Esse trabalho avaliou as consequências de fontes de campo magnético, ondas sonoras audíveis e de radiofreqüência e luz intensa pulsada na marcação de CS com 99mTc. Sangue de ratos Wistar foi exposto às fontes citadas. A marcação de CS com 99mTc foi realizada. Sangue não exposto foram utilizadas(controle. Resultados mostraram que os agentes físicos estudados não alteraram significativamente (p>0.05 a radiomarcação de CS. Apesar terem sido obtidos com sangue de animais, os resultados sugerem que nenhuma alteração nos exames realizados com constituintes sangüíneos com 99mTc em medicina nuclear ocorreria após a exposição às fontes avaliadas. As consequências biológicas associadas a esses agentes não seriam

  20. Real-time arrhythmia detection with supplementary ECG quality and pulse wave monitoring for the reduction of false alarms in ICUs.

    Science.gov (United States)

    Krasteva, Vessela; Jekova, Irena; Leber, Remo; Schmid, Ramun; Abächerli, Roger

    2016-08-01

    False intensive care unit (ICU) alarms induce stress in both patients and clinical staff and decrease the quality of care, thus significantly increasing both the hospital recovery time and rehospitalization rates. In the PhysioNet/CinC Challenge 2015 for reducing false arrhythmia alarms in ICU bedside monitor data, this paper validates the application of a real-time arrhythmia detection library (ADLib, Schiller AG) for the robust detection of five types of life-threatening arrhythmia alarms. The strength of the application is to give immediate feedback on the arrhythmia event within a scan interval of 3 s-7.5 s, and to increase the noise immunity of electrocardiogram (ECG) arrhythmia analysis by fusing its decision with supplementary ECG quality interpretation and real-time pulse wave monitoring (quality and hemodynamics) using arterial blood pressure or photoplethysmographic signals. We achieved the third-ranked real-time score (79.41) in the challenge (Event 1), however, the rank was not officially recognized due to the 'closed-source' entry. This study shows the optimization of the alarm decision module, using tunable parameters such as the scan interval, lead quality threshold, and pulse wave features, with a follow-up improvement of the real-time score (80.07). The performance (true positive rate, true negative rate) is reported in the blinded challenge test set for different arrhythmias: asystole (83%, 96%), extreme bradycardia (100%, 90%), extreme tachycardia (98%, 80%), ventricular tachycardia (84%, 82%), and ventricular fibrillation (78%, 84%). Another part of this study considers the validation of ADLib with four reference ECG databases (AHA, EDB, SVDB, MIT-BIH) according to the international recommendations for performance reports in ECG monitors (ANSI/AAMI EC57). The sensitivity (Se) and positive predictivity (+P) are: QRS detector QRS (Se, +P)  >  99.7%, ventricular ectopic beat (VEB) classifier VEB (Se, +P)  =  95%, and ventricular

  1. Photoelectrocatalytic decomposition of ethylene using TiO{sub 2}/activated carbon fiber electrode with applied pulsed direct current square-wave potential

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Sheng-ying, E-mail: yesy@scau.edu.cn; Zheng, Sen-hong; Song, Xian-liang; Luo, Shu-can

    2015-06-30

    Highlights: • Ethylene was decomposed by a photoelectrocatalytic (PEC) process. • A pulsed direct current square-wave (PDCSW) potential was applied to the PEC cell. • An electrode of TiO{sub 2} or modified TiO{sub 2} and activated carbon fiber (ACF) was used. • TiO{sub 2}/ACF photocatalyst electrodes were modified by gamma radiolysis. • Efficiencies of the PEC process were higher than those of the process using DC. - Abstract: Removing ethylene (C{sub 2}H{sub 4}) from the atmosphere of storage facilities for fruits and vegetable is one of the main challenges in their postharvest handling for maximizing their freshness, quality, and shelf life. In this study, we investigated the photoelectrocatalytic (PEC) degradation of ethylene gas by applying a pulsed direct current DC square-wave (PDCSW) potential and by using a Nafion-based PEC cell. The cell utilized a titanium dioxide (TiO{sub 2}) photocatalyst or γ-irradiated TiO{sub 2} (TiO{sub 2}{sup *}) loaded on activated carbon fiber (ACF) as a photoelectrode. The apparent rate constant of a pseudo-first-order reaction (K) was used to describe the PEC degradation of ethylene. Parameters of the potential applied to the PEC cell in a reactor that affect the degradation efficiency in terms of the K value were studied. These parameters were frequency, duty cycle, and voltage. Ethylene degradation by application of a constant PDCSW potential to the PEC electrode of either TiO{sub 2}/ACF cell or TiO{sub 2}{sup *}/ACF cell enhanced the efficiency of photocatalytic degradation and PEC degradation. Gamma irradiation of TiO{sub 2} in the electrode and the applied PDCSW potential synergistically increased the K value. Independent variables (frequency, duty cycle, and voltage) of the PEC cell fabricated from TiO{sub 2} subjected 20 kGy γ radiation were optimized to maximize the K value by using response surface methodology with quadratic rotation–orthogonal composite experimental design. Optimized conditions were as

  2. Measurement uncertainty in pulmonary vascular input impedance and characteristic impedance estimated from pulsed-wave Doppler ultrasound and pressure: clinical studies on 57 pediatric patients.

    Science.gov (United States)

    Tian, Lian; Hunter, Kendall S; Kirby, K Scott; Ivy, D Dunbar; Shandas, Robin

    2010-06-01

    Pulmonary vascular input impedance better characterizes right ventricular (RV) afterload and disease outcomes in pulmonary hypertension compared to the standard clinical diagnostic, pulmonary vascular resistance (PVR). Early efforts to measure impedance were not routine, involving open-chest measurement. Recently, the use of pulsed-wave (PW) Doppler-measured velocity to non-invasively estimate instantaneous flow has made impedance measurement more practical. One critical concern remains with clinical use: the measurement uncertainty, especially since previous studies only incorporated random error. This study utilized data from a large pediatric patient population to comprehensively examine the systematic and random error contributions to the total impedance uncertainty and determined the least error prone methodology to compute impedance from among four different methods. We found that the systematic error contributes greatly to the total uncertainty and that one of the four methods had significantly smaller propagated uncertainty; however, even when this best method is used, the uncertainty can be large for input impedance at high harmonics and for the characteristic impedance modulus. Finally, we found that uncertainty in impedance between normotensive and hypertensive patient groups displays no significant difference. It is concluded that clinical impedance measurement would be most improved by advancements in instrumentation, and the best computation method is proposed for future clinical use of the input impedance.

  3. Application of a Modified Entropy Computational Method in Assessing the Complexity of Pulse Wave Velocity Signals in Healthy and Diabetic Subjects

    Directory of Open Access Journals (Sweden)

    Yi-Chung Chang

    2014-07-01

    Full Text Available Using 1000 successive points of a pulse wave velocity (PWV series, we previously distinguished healthy from diabetic subjects with multi-scale entropy (MSE using a scale factor of 10. One major limitation is the long time for data acquisition (i.e., 20 min. This study aimed at validating the sensitivity of a novel method, short time MSE (sMSE that utilized a substantially smaller sample size (i.e., 600 consecutive points, in differentiating the complexity of PWV signals both in simulation and in human subjects that were divided into four groups: healthy young (Group 1; n = 24 and middle-aged (Group 2; n = 30 subjects without known cardiovascular disease and middle-aged individuals with well-controlled (Group 3; n = 18 and poorly-controlled (Group 4; n = 22 diabetes mellitus type 2. The results demonstrated that although conventional MSE could differentiate the subjects using 1000 consecutive PWV series points, sensitivity was lost using only 600 points. Simulation study revealed consistent results. By contrast, the novel sMSE method produced significant differences in entropy in both simulation and testing subjects. In conclusion, this study demonstrated that using a novel sMSE approach for PWV analysis, the time for data acquisition can be substantially reduced to that required for 600 cardiac cycles (~10 min with remarkable preservation of sensitivity in differentiating among healthy, aged, and diabetic populations.

  4. Development of a 2.0W at 60K single-stage coaxial pulse tube cryocooler for long-wave infrared focal plane array applications

    Science.gov (United States)

    Dang, H. Z.; Wang, L. B.; Wu, Y. N.; Yang, K. X.; Li, S. S.; Shen, W. B.

    2010-04-01

    A 2.0W@60K single-stage coaxial pulse tube cryocooler has been developed to provide reliable low-vibration cooling for the space-borne long wave infrared focal plane array. The coaxial configuration result in a compact system and the inertance tube together with a gas reservoir serves as the only phase-shifting to realize a highly reliable system. The inertance tube consists of two parts with different inner diameter and length to obtain the desirable phase relationship. Both cold tip and warm flange integrated with fine slit heat exchanges fabricated with electro discharge machining technology to enhance heat exchange performance. A split Oxford-type linear compressor with dual-opposed piston configuration is connected to the cold finger with a 30 cm flexible metallic tube. The overall weight without control electronics is below 8 kg. The preliminary experiments show that a no-load temperature of 46 K and a cooling power of 2 W at 60 K with 104 W of input power at 300K reject temperature have been achieved.

  5. Pulsed Wave Doppler Ultrasound Is Useful to Assess Vasomotor Response in Patients with Multiple System Atrophy and Well Correlated with Tilt Table Study

    Directory of Open Access Journals (Sweden)

    Ke-Vin Chang

    2012-01-01

    Full Text Available The study aim was to assess sympathetic vasomotor response (SVR by using pulsed wave Doppler (PWD ultrasound in patients with multiple system atrophy (MSA and correlate with the tilt table study. We recruited 18 male patients and 10 healthy men as controls. The SVR of the radial artery was evaluated by PWD, using inspiratory cough as a provocative maneuver. The response to head-up tilt was studied by a tilt table with simultaneous heart rate and blood pressure recording. The hemodynamic variables were compared between groups, and were examined by correlation analysis. Regarding SVR, MSA patients exhibited a prolonged latency and less heart rate acceleration following inspiratory cough. Compared with the tilt table test, the elevation of heart rate upon SVR was positively correlated to the increase of heart rate after head-up tilt. The correlation analysis indicated that the magnitude of blood pressure drop from supine to upright was positively associated with the SVR latency but negatively correlated with the heart rate changes upon SVR. The present study demonstrated that blunted heart rate response might explain MSA's vulnerability to postural challenge. PWD may be used to predict cardiovascular response to orthostatic stress upon head-up tilt in MSA patients.

  6. Pulse-Wave Analysis of Optic Nerve Head Circulation Is Significantly Correlated with Kidney Function in Patients with and without Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Tomoaki Shiba

    2014-01-01

    Full Text Available Aim. To determine whether there is a significant correlation between the optic nerve head (ONH circulation determined by laser speckle flowgraphy (LSFG and kidney function. Materials. Seventy-one subjects were investigated. The estimated glomerular filtration rate (GFR and serum creatinine, cystatin C, and urinary albumin excretion were measured. The ONH circulation was determined by an analysis of the pulse wave of LSFG, and this parameter was named blowout time (BOT. Chronic kidney disease (CKD was defined to be present when the estimated GFR was <60 mL/min per 1.73 m2. Pearson’s correlation coefficients were used to determine the relationship between the BOT and the kidney function. We also examined whether there were significant differences in all parameters in patients with and without CKD. Results. BOT was significantly correlated with the level of creatinine (r=-0.24, P=0.04, the estimated GFR (r=0.42, P=0.0003, cystatin C (r=-0.29, P=0.01, and urinary albumin excretion (r=-0.29, P=0.01. The BOT level in subjects with CKD was significantly lower than that in subjects without CKD (P=0.002. Conclusion. BOT in ONH by LSFG can detect the organ damage such as kidney dysfunction, CKD.

  7. The Detection and Exclusion of the Prostate Neuro-Vascular Bundle (NVB) in Automated HIFU Treatment Planning Using a Pulsed-Wave Doppler Ultrasound System

    Science.gov (United States)

    Chen, Wohsing; Carlson, Roy F.; Fedewa, Russell; Seip, Ralf; Sanghvi, Narendra T.; Dines, Kris A.; Pfile, Richard; Penna, Michael A.; Gardner, Thomas A.

    2005-03-01

    Men with prostate cancer are likely to develop impotence after prostate cancer therapy if the treatment damages the neuro-vascular bundles (NVB). The NVB are generally located at the periphery of the prostate gland. To preserve the NVB, a Doppler system is used to detect and localize the associated blood vessels. This information is used during the therapy planning procedure to avoid treatment surrounding the blood vessel areas. The Sonablate®500 (Focus Surgery, Inc.) image-guided HIFU device is enhanced with a pulse-wave multi-gate Doppler system that uses the current imaging transducer and mechanical scanner to acquire Doppler data. Doppler detection is executed after the regular B-mode images are acquired from the base to the apex of the prostate using parallel sector scans. The results are stored and rendered in 3-D display, registered with additional models generated for the capsule, urethra, and rectal wall, and the B-mode data and treatment plan itself. The display of the blood flow can be in 2-D color overlaid on the B-mode image or in 3-D color structure. Based on this 3-D model, the HIFU treatment planning can be executed in automated or manual mode by the physician to remove originally defined treatment zones that overlap with the NVB (for preservation of NVB). The results of the NVB detection in animal experiments, and the 3-D modeling and data registration of the prostate will be presented.

  8. Measurement uncertainty in pulmonary vascular input impedance and characteristic impedance estimated from pulsed-wave Doppler ultrasound and pressure: clinical studies on 57 pediatric patients

    International Nuclear Information System (INIS)

    Pulmonary vascular input impedance better characterizes right ventricular (RV) afterload and disease outcomes in pulmonary hypertension compared to the standard clinical diagnostic, pulmonary vascular resistance (PVR). Early efforts to measure impedance were not routine, involving open-chest measurement. Recently, the use of pulsed-wave (PW) Doppler-measured velocity to non-invasively estimate instantaneous flow has made impedance measurement more practical. One critical concern remains with clinical use: the measurement uncertainty, especially since previous studies only incorporated random error. This study utilized data from a large pediatric patient population to comprehensively examine the systematic and random error contributions to the total impedance uncertainty and determined the least error prone methodology to compute impedance from among four different methods. We found that the systematic error contributes greatly to the total uncertainty and that one of the four methods had significantly smaller propagated uncertainty; however, even when this best method is used, the uncertainty can be large for input impedance at high harmonics and for the characteristic impedance modulus. Finally, we found that uncertainty in impedance between normotensive and hypertensive patient groups displays no significant difference. It is concluded that clinical impedance measurement would be most improved by advancements in instrumentation, and the best computation method is proposed for future clinical use of the input impedance

  9. Electromagnetic Guide Wave Excitation Resource Optimal Design Based on isolated Current Pulse Group%基于孤立电流脉冲群的电磁导波激励源优化设计

    Institute of Scientific and Technical Information of China (English)

    李勇; 米东; 刘美全; 周海林

    2011-01-01

    目前,电磁导波检测系统的激励源大都采用重复电流脉冲群+高频大功率放大器输出大电流脉冲的方式,由于这种电流脉冲是连续的,平均功耗较大,成本高,不利于系统的简单化和实用化;通过电路分析和电路参数的优化选取,给出了电容储能放电产生孤立电流脉冲群作为电磁导波激励信号的新方法,整个系统设计简单,无需功率放大器放大,成本大为降低;实际放电波形表明:这种激励信号瞬时电流很高,能达到重复脉冲群激励信号的3倍以上,完全满足实际电磁导波检测要求.%The excitation resource of the electromagnetic guide wave detection system almost adopts the way of repeated current pulse group + high frequency and high power amplifier. That is a way which has continuous current pulse and high power consumption and high cost. A new way has been provided by circuit analysis and the optimal select of circuit parameter. The excitation resource of the electromagnetic guide wave is isolated current pulse group by capacitance energy storage and discharge. The system has the characteristic of simple and without power amplifier and low cost. The real discharge wave shows that this excitation signal has high instantaneous current and 3 times than that of repeated pulse group and the best demand for real electromagnetic guide wave detection.

  10. Impact of changes in systemic vascular resistance on a novel non-invasive continuous cardiac output measurement system based on pulse wave transit time: a report of two cases

    OpenAIRE

    Ishihara, Hironori; Tsutsui, Masato

    2013-01-01

    The inaccuracy of arterial waveform analysis for measuring continuos cardiac output (CCO) associated with changes in systemic vascular resistance (SVR) has been well documented. A new non-invasive continuous cardiac output monitoring system (esCCO) mainly utilizing pulse wave transit time (PWTT) in place of arterial waveform analysis has been developed. However, the trending ability of esCCO to measure cardiac output during changes in SVR remains unclear. After a previous multicenter study on...

  11. 环境温度对指端容积脉搏波检测精度的影响%Effect of local temperature on the detecting for pulse wave of local blood volume

    Institute of Scientific and Technical Information of China (English)

    高鑫; 闫亭亭; 邵常哲; 杨琳; 张松; 杨益民

    2012-01-01

    目的 探讨环境温度对指端容积脉搏波的影响.方法 用凉水将32名受试者手指温度降至20℃,检测其容积脉搏波,并用温度计实时检测温度,记录波形,至手指温度恢复到实验前测量数值.结果 当被测部位温度在26~31℃时,所获得的容积脉搏波参数K′、K1′、K2′及容积脉搏波幅值均无显著差异.结论 当手指温度高于26℃时可进行指端容积脉搏波的检测,在26~31℃检测获得的容积脉搏波的基本参数无显著差异.%To investigate the effect of temperature on subjected part in pulse wave of local blood volume measurement. Methods When the 32 experimenters' finger temperature fall below 20 ℃ , their pulse waves of local blood volume are recorded until the temperature returns to the original and the temperature of finger are real-time detected. Results While the temperature of subjected part ranges from 26℃ to 31℃, the parameters of K', Kt', K2'and the amplitude of pulse wave are unchanged. Conclusions Only if the finger temperature is in the range of 26℃to 31℃ , can the pulse wave of local blood volume be measured.

  12. Pulse Wave Signal Preprocessing in Real-time Monitoring Oxygen Saturation%血氧饱和度实时监测中脉搏波信号的预处理

    Institute of Scientific and Technical Information of China (English)

    张莉; 曹阳

    2012-01-01

    Objective To pre-process original pulse wave signal from photoelectric oxygen saturation monitoring system in order to improve real-time and accuracy of calculating relevant parameters. Methods Characters of noise in original pulse wave signal were analyzed, methods were suggested in preprocessing pulse wave signal and relevant filter was designed based on the characters, MATLAB software was used to process and simulate these data. Results After processing, original pulse wave signal's noise was eliminated while accuracy of calculating parameters being improved. Conclusion oxygen saturation's fast measurement and real-time dynamic monitoring are achieved, and foundation of calculating parameters isestablished.[Chinese Medical Equipment Journal,2011,33(1):19-21]%目的:对光电脉搏式血氧饱和度监测系统采集的脉搏波信号进行预处理,提高参数计算的实时性与准确性.方法:对原始脉搏波信号噪声特点进行分析,提出相关的预处理方法并设计相应的滤波器,利用Matlab数据分析软件对脉搏波信号及相关参数进行仿真处理.结果:原始脉搏波信号经处理后,在提高运算精度的同时消除了噪声干扰.结论:实现了血氧饱和度的实时快速测量和动态监测显示,为血氧饱和度参数的计算奠定了基础.

  13. Determination of Diastolic Dysfunction Cut-Off Value by Tissue Doppler Imaging in Adults 70 Years of Age or Older: A Comparative Analysis of Pulsed-Wave and Color-Coded Tissue Doppler Imaging

    OpenAIRE

    Baek, Hee-Kyung; Park, Tae-Ho; Park, Sun-Yi; Kim, Jung-Hwan; Seo, Jeong-Min; Kim, Woo-Jae; Nam, Young-Hee; Kim, Moo-Hyun; Kim, Young-Dae

    2011-01-01

    Background and Objectives The cut-off value of diastolic dysfunction by tissue Doppler imaging (TDI) is affected by aging and modalities used (pulsed-wave vs. color-coded). The purpose of this study was to investigate the diastolic function of healthy elderly people and to determine the appropriate cut-off value of diastolic dysfunction in elderly individuals. Subjects and Methods Healthy volunteers (n=76) and patients with hypertension (n=51) aged ≥70 years underwent 2-dimensional and Dopple...

  14. 脉冲式与连续波式导航雷达反截获能力分析%Analysis of Anti-interception Capability of Pulsed and Continuous-wave Navigation Radars

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      为了分析脉冲雷达与连续波雷达的探测效能,重点研究了在不同蒸发波导高度条件下两种体制导航雷达的反截获能力。首先给出了脉冲式和连续波式导航雷达截获因子的度量方法,然后对这两种体制的雷达在标准大气和蒸发波导条件下的截获因子进行了仿真。仿真结果表明,在反截获方面,连续波式导航雷达明显优于脉冲式导航雷达。%To analyze the detection performance of pulsed and continuous-wave radars, this paper focuses on the anti-interception capability of two types of systems of navigation radars under the circumstances of various evaporation ducts’altitude. Firstly, the measurement method for intercept factors of pulsed and continuous-wave radars is given, and then the intercept factors of these two systems of radars are simulated on the condition of standard air pressure and evaporation ducts. Simulation results show that the continuous-wave type of navigation radar is superior to the pulsed type in terms of anti-interception.

  15. Tailoring giant magnetoimpedance effect of Co-based microwires for optimum efficiency by self-designed square-wave pulse current annealing

    International Nuclear Information System (INIS)

    Herein, we systematically studied the effect of a novel square-wave pulse current annealing (SPCA) on the magnetic properties and microstructure of Co-based melt-extracted amorphous wires, and efficiently tailored the related experimental parameters by using numerical calculation of transient temperature rise during SPCA process. We obtained the optimal SPCA treatment (at 50 Hz, with amplitude of 90 mA for 480 s) can remarkably enhance the GMI property of as-prepared wires. At 10 MHz, the maximum GMI ratio [ΔZ/Z0]max and maxima response sensitivity ξmax of SPCA-treated wire increases to 202.60% and 305.74%/Oe, which is nearly two times and 1.5 times of 104.80% and 208.14%/Oe for as-cast wire, respectively. Especially, at 5 MHz, [ΔZ/Z0]max of SPCA-treated wire increases to 185.81%, which is 2.5 times of 73.69% for as-cast wire, and ξmax of SPCA-treated wire increases to 346.65%/Oe by less than two times of 190.16%/Oe for as-cast wire. From mictrostructural perspective, the notably observed role of atomic order orientation regimes and circular magnetic domain during stress releasing or structural relaxation by the co-action of high-density pulse magnetic field energy and thermal activation energy determines the optimum efficiency of SPCA, further to enhance circumferential permeability. In conclusion, SPCA treatment is expected to effectively improve GMI property of microwires, which can be used as sensitive materials for potential sensor application in detecting weak magnetic field. - Highlights: • Annealing parameters are optimized by transient temperature rising calculation. • SPCA as a novel annealing treatment has larger GMI ratio and field sensitivity. • GMI effect is generally related to annealed microstructures identified by XRD. • Domain observed by MFM to explain the enhanced GMI property for SPCA-ed wires. • Results indicate SPCA-ed wires are useful for potential GMI sensor applications

  16. Tailoring giant magnetoimpedance effect of Co-based microwires for optimum efficiency by self-designed square-wave pulse current annealing

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jingshun, E-mail: jingshun_liu@163.com [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Du, Zhaoxin [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Jiang, Sida; Shen, Hongxian [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Li, Ze [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Xing, Dawei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Ma, Wen [School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051 (China); Sun, Jianfei [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2015-07-01

    Herein, we systematically studied the effect of a novel square-wave pulse current annealing (SPCA) on the magnetic properties and microstructure of Co-based melt-extracted amorphous wires, and efficiently tailored the related experimental parameters by using numerical calculation of transient temperature rise during SPCA process. We obtained the optimal SPCA treatment (at 50 Hz, with amplitude of 90 mA for 480 s) can remarkably enhance the GMI property of as-prepared wires. At 10 MHz, the maximum GMI ratio [ΔZ/Z{sub 0}]{sub max} and maxima response sensitivity ξ{sub max} of SPCA-treated wire increases to 202.60% and 305.74%/Oe, which is nearly two times and 1.5 times of 104.80% and 208.14%/Oe for as-cast wire, respectively. Especially, at 5 MHz, [ΔZ/Z{sub 0}]{sub max} of SPCA-treated wire increases to 185.81%, which is 2.5 times of 73.69% for as-cast wire, and ξ{sub max} of SPCA-treated wire increases to 346.65%/Oe by less than two times of 190.16%/Oe for as-cast wire. From mictrostructural perspective, the notably observed role of atomic order orientation regimes and circular magnetic domain during stress releasing or structural relaxation by the co-action of high-density pulse magnetic field energy and thermal activation energy determines the optimum efficiency of SPCA, further to enhance circumferential permeability. In conclusion, SPCA treatment is expected to effectively improve GMI property of microwires, which can be used as sensitive materials for potential sensor application in detecting weak magnetic field. - Highlights: • Annealing parameters are optimized by transient temperature rising calculation. • SPCA as a novel annealing treatment has larger GMI ratio and field sensitivity. • GMI effect is generally related to annealed microstructures identified by XRD. • Domain observed by MFM to explain the enhanced GMI property for SPCA-ed wires. • Results indicate SPCA-ed wires are useful for potential GMI sensor applications.

  17. Sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy setup for pulsed and constant wave X-ray light sources

    Energy Technology Data Exchange (ETDEWEB)

    Shavorskiy, Andrey; Slaughter, Daniel S.; Zegkinoglou, Ioannis; Rude, Bruce S.; Bluhm, Hendrik [Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Neppl, Stefan; Cryan, James P.; Siefermann, Katrin R.; Weise, Fabian; Lin, Ming-Fu; Bacellar, Camila; Ziemkiewicz, Michael P.; Fraund, Matthew W.; Khurmi, Champak; Wright, Travis W.; Schoenlein, Robert W.; Gessner, Oliver, E-mail: ogessner@lbl.gov [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Hertlein, Marcus P.; Tyliszczak, Tolek [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Huse, Nils [Ultrafast X-ray Science Laboratory, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Physics Department, University of Hamburg and Max-Planck Institute for Structure and Dynamics of Matter, 22761 Hamburg (Germany); and others

    2014-09-15

    An apparatus for sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy studies with pulsed and constant wave X-ray light sources is presented. A differentially pumped hemispherical electron analyzer is equipped with a delay-line detector that simultaneously records the position and arrival time of every single electron at the exit aperture of the hemisphere with ∼0.1 mm spatial resolution and ∼150 ps temporal accuracy. The kinetic energies of the photoelectrons are encoded in the hit positions along the dispersive axis of the two-dimensional detector. Pump-probe time-delays are provided by the electron arrival times relative to the pump pulse timing. An average time-resolution of (780 ± 20) ps (FWHM) is demonstrated for a hemisphere pass energy E{sub p} = 150 eV and an electron kinetic energy range KE = 503–508 eV. The time-resolution of the setup is limited by the electron time-of-flight (TOF) spread related to the electron trajectory distribution within the analyzer hemisphere and within the electrostatic lens system that images the interaction volume onto the hemisphere entrance slit. The TOF spread for electrons with KE = 430 eV varies between ∼9 ns at a pass energy of 50 eV and ∼1 ns at pass energies between 200 eV and 400 eV. The correlation between the retarding ratio and the TOF spread is evaluated by means of both analytical descriptions of the electron trajectories within the analyzer hemisphere and computer simulations of the entire trajectories including the electrostatic lens system. In agreement with previous studies, we find that the by far dominant contribution to the TOF spread is acquired within the hemisphere. However, both experiment and computer simulations show that the lens system indirectly affects the time resolution of the setup to a significant extent by inducing a strong dependence of the angular spread of electron trajectories entering the hemisphere on the retarding ratio. The scaling of the angular

  18. Sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy setup for pulsed and constant wave X-ray light sources.

    Science.gov (United States)

    Shavorskiy, Andrey; Neppl, Stefan; Slaughter, Daniel S; Cryan, James P; Siefermann, Katrin R; Weise, Fabian; Lin, Ming-Fu; Bacellar, Camila; Ziemkiewicz, Michael P; Zegkinoglou, Ioannis; Fraund, Matthew W; Khurmi, Champak; Hertlein, Marcus P; Wright, Travis W; Huse, Nils; Schoenlein, Robert W; Tyliszczak, Tolek; Coslovich, Giacomo; Robinson, Joseph; Kaindl, Robert A; Rude, Bruce S; Ölsner, Andreas; Mähl, Sven; Bluhm, Hendrik; Gessner, Oliver

    2014-09-01

    An apparatus for sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy studies with pulsed and constant wave X-ray light sources is presented. A differentially pumped hemispherical electron analyzer is equipped with a delay-line detector that simultaneously records the position and arrival time of every single electron at the exit aperture of the hemisphere with ~0.1 mm spatial resolution and ~150 ps temporal accuracy. The kinetic energies of the photoelectrons are encoded in the hit positions along the dispersive axis of the two-dimensional detector. Pump-probe time-delays are provided by the electron arrival times relative to the pump pulse timing. An average time-resolution of (780 ± 20) ps (FWHM) is demonstrated for a hemisphere pass energy E(p) = 150 eV and an electron kinetic energy range KE = 503-508 eV. The time-resolution of the setup is limited by the electron time-of-flight (TOF) spread related to the electron trajectory distribution within the analyzer hemisphere and within the electrostatic lens system that images the interaction volume onto the hemisphere entrance slit. The TOF spread for electrons with KE = 430 eV varies between ~9 ns at a pass energy of 50 eV and ~1 ns at pass energies between 200 eV and 400 eV. The correlation between the retarding ratio and the TOF spread is evaluated by means of both analytical descriptions of the electron trajectories within the analyzer hemisphere and computer simulations of the entire trajectories including the electrostatic lens system. In agreement with previous studies, we find that the by far dominant contribution to the TOF spread is acquired within the hemisphere. However, both experiment and computer simulations show that the lens system indirectly affects the time resolution of the setup to a significant extent by inducing a strong dependence of the angular spread of electron trajectories entering the hemisphere on the retarding ratio. The scaling of the angular spread with

  19. Sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy setup for pulsed and constant wave X-ray light sources.

    Science.gov (United States)

    Shavorskiy, Andrey; Neppl, Stefan; Slaughter, Daniel S; Cryan, James P; Siefermann, Katrin R; Weise, Fabian; Lin, Ming-Fu; Bacellar, Camila; Ziemkiewicz, Michael P; Zegkinoglou, Ioannis; Fraund, Matthew W; Khurmi, Champak; Hertlein, Marcus P; Wright, Travis W; Huse, Nils; Schoenlein, Robert W; Tyliszczak, Tolek; Coslovich, Giacomo; Robinson, Joseph; Kaindl, Robert A; Rude, Bruce S; Ölsner, Andreas; Mähl, Sven; Bluhm, Hendrik; Gessner, Oliver

    2014-09-01

    An apparatus for sub-nanosecond time-resolved ambient-pressure X-ray photoelectron spectroscopy studies with pulsed and constant wave X-ray light sources is presented. A differentially pumped hemispherical electron analyzer is equipped with a delay-line detector that simultaneously records the position and arrival time of every single electron at the exit aperture of the hemisphere with ~0.1 mm spatial resolution and ~150 ps temporal accuracy. The kinetic energies of the photoelectrons are encoded in the hit positions along the dispersive axis of the two-dimensional detector. Pump-probe time-delays are provided by the electron arrival times relative to the pump pulse timing. An average time-resolution of (780 ± 20) ps (FWHM) is demonstrated for a hemisphere pass energy E(p) = 150 eV and an electron kinetic energy range KE = 503-508 eV. The time-resolution of the setup is limited by the electron time-of-flight (TOF) spread related to the electron trajectory distribution within the analyzer hemisphere and within the electrostatic lens system that images the interaction volume onto the hemisphere entrance slit. The TOF spread for electrons with KE = 430 eV varies between ~9 ns at a pass energy of 50 eV and ~1 ns at pass energies between 200 eV and 400 eV. The correlation between the retarding ratio and the TOF spread is evaluated by means of both analytical descriptions of the electron trajectories within the analyzer hemisphere and computer simulations of the entire trajectories including the electrostatic lens system. In agreement with previous studies, we find that the by far dominant contribution to the TOF spread is acquired within the hemisphere. However, both experiment and computer simulations show that the lens system indirectly affects the time resolution of the setup to a significant extent by inducing a strong dependence of the angular spread of electron trajectories entering the hemisphere on the retarding ratio. The scaling of the angular spread with

  20. Pulsed-wave tissue Doppler imaging of the myocardium of cats with induced thyrotoxicosis Doppler tecidual pulsado do miocárdio de gatos com tirotoxicose induzida

    Directory of Open Access Journals (Sweden)

    Daniel Capucho de Oliveira

    2011-06-01

    Full Text Available Left ventricular myocardial motion was quantified using pulsed-wave tissue Doppler imaging (PW-TDI in nine adult cats before and after thyrotoxicosis induction. In order to induce thyrotoxicosis, all cats were given 150µg kg-1 of levothyroxine sodium as a single oral dose each day for 10 weeks. PW-TDI examinations were performed immediately before the induction and by the end of the experimental protocol. An increase in myocardial motion velocity was documented at the interventricular septum level, demonstrated by an elevation in systolic (Sa, and early (Ea and late (Aa diastolic waves (PA velocidade de movimentação miocárdica do ventrículo esquerdo foi quantificada por meio de exames ecocardiográficos com Doppler tecidual pulsado (PW-TDI em nove gatos adultos antes e após indução à tirotoxicose. Para indução da tirotoxicose, todos os gatos receberam doses diárias de 150mg kg-1 de levotiroxina sódica, por via oral, durante 10 semanas. Os exames de PW-TDI foram realizados imediatamente antes da indução e ao final do protocolo experimental. Uma elevação na velocidade de movimentação miocárdica foi documentada ao nível do septo interventricular, demonstrado por um aumento das ondas sistólica (Sa e diastólicas (Ea e Aa; P<0,05. No entanto, nenhuma alteração nos valores de Sa, Ea e Aa foi encontrada ao nível da parede livre do ventrículo esquerdo. A frequência cardíaca aumentou significativamente entre os momentos experimentais, sendo que três animais apresentaram fusão das ondas Aa e Ea ao final do experimento. O protocolo experimental utilizado neste estudo causou alterações na velocidade de movimentação do miocárdio ventricular esquerdo, mas sem causar danos à função diastólica do ventrículo esquerdo.

  1. Robot-assisted gait training improves brachial–ankle pulse wave velocity and peak aerobic capacity in subacute stroke patients with totally dependent ambulation

    Science.gov (United States)

    Han, Eun Young; Im, Sang Hee; Kim, Bo Ryun; Seo, Min Ji; Kim, Myeong Ok

    2016-01-01

    Abstract Objective: Brachial–ankle pulse wave velocity (baPWV) evaluates arterial stiffness and also predicts early outcome in stroke patients. The objectives of this study were to investigate arterial stiffness of subacute nonfunctional ambulatory stroke patients and to compare the effects of robot-assisted gait therapy (RAGT) combined with rehabilitation therapy (RT) on arterial stiffness and functional recovery with those of RT alone. Method: The RAGT group (N = 30) received 30 minutes of robot-assisted gait therapy and 30 minutes of conventional RT, and the control group (N = 26) received 60 minutes of RT, 5 times a week for 4 weeks. baPWV was measured and calculated using an automated device. The patients also performed a symptom-limited graded exercise stress test using a bicycle ergometer, and parameters of cardiopulmonary fitness were recorded. Clinical outcome measures were categorized into 4 categories: activities of daily living, balance, ambulatory function, and paretic leg motor function and were evaluated before and after the 4-week intervention. Results: Both groups exhibited significant functional recovery in all clinical outcome measures after the 4-week intervention. However, peak aerobic capacity, peak heart rate, exercise tolerance test duration, and baPWV improved only in the RAGT group, and the improvements in baPWV and peak aerobic capacity were more noticeable in the RAGT group than in the control group. Conclusion: Robot-assisted gait therapy combined with conventional rehabilitation therapy represents an effective method for reversing arterial stiffness and improving peak aerobic capacity in subacute stroke patients with totally dependent ambulation. However, further large-scale studies with longer term follow-up periods are warranted to measure the effects of RAGT on secondary prevention after stroke. PMID:27741123

  2. As compared to allopurinol, urate-lowering therapy with febuxostat has superior effects on oxidative stress and pulse wave velocity in patients with severe chronic tophaceous gout.

    Science.gov (United States)

    Tausche, A-K; Christoph, M; Forkmann, M; Richter, U; Kopprasch, S; Bielitz, C; Aringer, M; Wunderlich, C

    2014-01-01

    We prospectively evaluated whether an effective 12-month uric acid-lowering therapy (ULT) with the available xanthine oxidase (XO) inhibitors allopurinol and febuxostat in patients with chronic tophaceous gout has an impact on oxidative stress and/or vascular function. Patients with chronic tophaceous gout who did not receive active ULT were included. After clinical evaluation, serum uric acid levels (SUA) and markers of oxidative stress were measured, and carotid-femoral pulse wave velocity (cfPWV) was assessed. Patients were then treated with allopurinol (n = 9) or with febuxostat (n = 8) to target a SUA level ≤ 360 μmol/L. After 1 year treatment, the SUA levels, markers of oxidative stress and the cfPWV were measured again. Baseline characteristics of both groups showed no significant differences except a higher prevalence of moderate impairment of renal function (estimated glomerular filtration rate treatment groups did not differ in their baseline cfPWV (allopurinol group: 14.1 ± 3.4 m/s, febuxostat group: 13.7 ± 2.7 m/s, p = 0.80). However, after 1 year of therapy, we observed a significant cfPWV increase in the allopurinol group (16.8 ± 4.3 m/s, p = 0.001 as compared to baseline), but not in the febuxostat patients (13.3 ± 2.3 m/s, p = 0.55). Both febuxostat and allopurinol effectively lower SUA levels in patients with severe gout. However, we observed that febuxostat also appeared to be beneficial in preventing further arterial stiffening. Since cardiovascular events are an important issue in treating patients with gout, this unexpected finding may have important implications and should be further investigated in randomized controlled trials.

  3. Reduction in visceral adiposity is highly related to improvement in vascular endothelial dysfunction among obese women: an assessment of endothelial function by radial artery pulse wave analysis.

    Science.gov (United States)

    Park, Si-Hoon; Shim, Kyung-Won

    2005-08-31

    Because obesity is frequently complicated by other cardiovascular risk factors, the impact of a reduction in visceral adiposity on vascular endothelial dysfunction (VED) in obese patients is difficult to determine. In the present study, we evaluated the impact of a reduction in visceral adiposity on VED in obese women. Thirty-six premenopausal obese women (BMI >/= 25 kg/m2) without complications were enrolled in the study. VED was evaluated by determining the augmentation index (AIx) from radial artery pulse waves obtained by applanation tonometry. Changes in AIx in response to nitroglycerin- induced endothelium-independent vasodilatation (DeltaAIx-NTG) and in response to salbutamol administration (DeltaAIx-Salb) were determined before and after weight reduction. After a 12-week weight reduction program, the average weight loss was 7.96 +/- 3.47 kg, with losses of 21.88 +/- 20.39 cm2 in visceral fat areas (p analysis combined with provocative pharmacological testing demonstrated preserved endothelium-independent vasodilation in healthy premenopausal obese women (DeltaAIx-NTG: 31.36 +/- 9.80% before weight reduction vs. 28.25 +/- 11.21% after weight reduction, p > 0.1) and an improvement in endothelial-dependent vasodilation following weight reduction (DeltaAIx-Salb: 10.03 +/- 6.49% before weight reduction vs. 19.33 +/- 9.28% after reduction, p VED. This finding suggests that reduction of visceral adiposity may be as important as the control of other major risk factors in the prevention of atherosclerosis in obese women. PMID:16127776

  4. Traveling wave laser system

    International Nuclear Information System (INIS)

    The invention broadly involves a method and means for generating a traveling wave laser pulse and is basically analogous to a single pass light amplifier system. However, the invention provides a traveling wave laser pulse of almost unlimited energy content, wherein a gain medium is pumped in a traveling wave mode, the traveling wave moving at essentially the velocity of light to generate an amplifying region or zone which moves through the medium at the velocity of light in the presence of directed stimulating radiation, thereby generating a traveling coherent, directed radiation pulse moving with the amplification zone through the gain medium. (U.S.)

  5. Relativistic spherical plasma waves

    CERN Document Server

    Bulanov, S S; Schroeder, C B; Zhidkov, A G; Esarey, E; Leemans, W P

    2011-01-01

    Tightly focused laser pulses as they diverge or converge in underdense plasma can generate wake waves, having local structures that are spherical waves. Here we report on theoretical study of relativistic spherical wake waves and their properties, including wave breaking. These waves may be suitable as particle injectors or as flying mirrors that both reflect and focus radiation, enabling unique X-ray sources and nonlinear QED phenomena.

  6. Traveling wave laser system

    International Nuclear Information System (INIS)

    A method is described for generating a traveling wave laser pulse of almost unlimited energy content wherein a gain medium is pumped into a traveling wave mode, the traveling wave moving at essentially the velocity of light to generate an amplifying region or zone which moves through the medium at the velocity of light in the presence of directed stimulating radiation, thereby generating a traveling coherent, directed radiation pulse moving with the amplification zone through the gain medium. (U.S.)

  7. 时间反演脉冲电磁波在双负材料中传播特性研究%Propagation characteristics of time reversal pulsed electromagnetic waves in double negative materials

    Institute of Scientific and Technical Information of China (English)

    赵德双; 岳文君; 余敏; 张升学

    2012-01-01

    With the full time-domain electromagnetic simulation technique,the time-domain propagation properties such as the temporal pulse waveform,the pulse compression and the electric field distribution inside the material are comparably investigated by transmitting the time-reversal pulsed electromagnetic wave and the pulsed electromagnetic wave through the double negative material of the Smith structure,respectively.The results show that after the time-reversal pulsed electromagnetic wave passes through the double negative material,the received electromagnetic wave exhibits remarkable spatial and temporal focusing at the location of the initial excitation. The most interesting physical phenomenon is that the peak values of the electric field inside the double negative material become smaller and tend to be uniform in the magnitude.These novel physical phenomena would be very helpful for developing new electronic devices and systems with double negative materials for the purpose of high power applications.%利用全时域电磁仿真技术,对比研究了时间反演脉冲电磁波和脉冲电磁波透过Smith结构双负材料后的时域波形、脉宽压缩以及材料内部空间电场峰值强度分布等时域传播特性.结果表明:时间反演脉冲电磁波在透过双负材料后,在初始源激励处表现出良好的时间和空间聚焦特性.更重要的是,在双负材料内部,观测到了电场峰值强度减弱、截面电场峰值强度趋向均衡分布等新型的物理现象.这些物理现象对发展能够承受大功率新型的双负材料电子器件及其应用系统很有参考研究价值.

  8. Performance Analysis of Multiple Access 60 GHz System Using Frequency-shifted Gaussian Pulse and Non-carrier PSWF Pulse

    OpenAIRE

    Hao Zhang; Wei Shi; Tingting Lu; Jingjing Wang; Xinjie Wang

    2013-01-01

    In this paper, a kind of impulse radio (IR) 60 GHz pulse based on Prolate Spheroidal Wave Functions (PSWF) is proposed. The capacity and performance for multiple access 60 GHz communication system based on carrier pulse and impulse radio pulse are analyzed separately. Both frequency-shifted Gaussian pulse and Prolate Spheroidal Wave Functions (PSWF) pulse are considered and devised according to the federal communication commission (FCC) power constraints. Pulse position modulation (PPM) with ...

  9. Experimental research on pulse forming based on high-temperature SMES applied in pulsed power

    Science.gov (United States)

    Zhou, Yusheng; Kuang, Jianghua; Tang, Yuejin; Song, Meng; Wei, Bin; Cheng, Shijie; Pan, Yuan

    2009-03-01

    To research the key problems of storage energy and pulse forming in pulsed power, a pulse magnet made of Bi2223/Ag high-temperature superconducting (HTS) tapes applied in pulsed power experiment was developed. After determining electromagnetic characteristics of the magnet, a pulse forming network was designed. HTS magnet was immersed in liquid nitrogen bath, experiments were carried out about discharging pulse current to resistance load based on HTS magnet energy storage (SMES). The results show that pulse current waves were obtained through adjusted circuit construction and magnet parameters by acting delay of switches in the pulse forming network. The technical schemes about pulse forming based on SMES were presented.

  10. Bragg grating rogue wave

    CERN Document Server

    Degasperis, Antonio; Aceves, Alejandro B

    2015-01-01

    We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing, may lead to extreme waves at extremely low powers.

  11. Bragg grating rogue wave

    Energy Technology Data Exchange (ETDEWEB)

    Degasperis, Antonio [Dipartimento di Fisica, “Sapienza” Università di Roma, P.le A. Moro 2, 00185 Roma (Italy); Wabnitz, Stefan, E-mail: stefan.wabnitz@unibs.it [Dipartimento di Ingegneria dell' Informazione, Università degli Studi di Brescia and INO-CNR, via Branze 38, 25123 Brescia (Italy); Aceves, Alejandro B. [Southern Methodist University, Dallas (United States)

    2015-06-12

    We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing may lead to extreme waves at extremely low powers.

  12. Markers of Mineral Metabolism Are Not Associated With Aortic Pulse Wave Velocity in Community-Living Elderly Persons: The Health Aging and Body Composition Study

    Science.gov (United States)

    Madero, Magdalena; Wassel, Christina L.; Peralta, Carmen A.; Najjar, Samer S.; Sutton-Tyrrell, Kim; Fried, Linda F.; de Boer, Ian H.; Shlipak, Michael G.; Newman, Anne B.; Hausman, Dorothy; Sarnak, Mark J.; Kritchevsky, Stephen B.; Ix, Joachim H.

    2011-01-01

    BACKGROUND Disorders in mineral metabolism are associated with risk for cardiovascular disease (CVD) events in patients with kidney disease as well as in the general population. This risk is thought to be mediated, in part, through the mechanism of stiffening of the arteries. METHODS The objective of this study was to evaluate the relationships between serum calcium, phosphorus, intact parathyroid hormone (iPTH), and 25-hydroxyvitamin D levels and arterial pulse wave velocity (aPWV) among 2,229 community-dwelling elderly persons participating in the Health Aging and Body Composition (Health ABC) study. RESULTS The mean age of the participants was 72 years; 52% were woman, 39% were black, and 17% had chronic kidney disease (CKD) (estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2). In parallel unadjusted analyses, the following associations were observed: 2.86% greater aPWV per 12 ng/ml (s.d.) lower 25-hydroxyvitamin D (95% confidence interval −4.38%, −1.31%), 3.04% greater aPWV per 28 pg/ml (s.d.) higher iPTH (95% confidence interval 1.42–4.68%), and 2.37% lower aPWV per 0.5 mg/dl (s.d.) higher phosphorus (95% confidence interval −3.90% to − 0.81%). Except for phosphorus, these associations were attenuated and rendered no longer statistically significant after adjustment for demographic risk factors, clinical site, season, medications and other CVD risk factors. The results were similar in men and women and were not dependent on the presence of CKD. CONCLUSIONS Among well-functioning community-dwelling elderly persons, only serum phosphorus was associated with aPWV; and this association was in the opposite direction of the one hypothesized. Factors other than vascular stiffening may mediate the relationship between disordered mineral metabolism and CVD events in community-living elders. PMID:21436791

  13. 三极管2SC3402方波电磁脉冲效应实验研究%Experimental studies on square wave electromagnetic pulse effect for the semiconductor triode 2SC3402

    Institute of Scientific and Technical Information of China (English)

    王瑞军; 康洪波

    2009-01-01

    Silicon micro-wave low-noise triode, such as 2SC3402 has carried on experiments of the square wave electromagnetic pulse effect and get some initial conclusions. The experiment follows that the triode's most sensitive position of square wave electromagnetic pulse is the collector junction. The most sensitive parameters are the reverse breakdown voltage V_(BRCEO) between collector and emitter.%针对硅微波低噪声三极管2SC3402进行方波电磁脉冲效应实验,主要研究三极管在方波电磁脉冲作用下哪些部位对电磁脉冲最为敏感,哪些电参数最容易发生变化.实验采用方波电磁脉冲发生器对三极管进行方波电磁脉冲注入,观察三极管电参数的变化.实验结果表明,三极管对电磁脉冲最敏感的部位是集电结,最灵敏参数是CE反向击穿电压V_(BRCEO).

  14. A Compact High Voltage Pulse Generator for Bounded-wave EMP Simulator%用于有界波模拟器的紧凑型纳秒脉冲源

    Institute of Scientific and Technical Information of China (English)

    谢霖燊; 贾伟; 郭帆; 陈维青; 陈志强; 金廷军

    2014-01-01

    With the development of electromagnetic weapons, nuclear electromagnetic pulse and its engineering protection technology has attracted world-wide attention. For simulating the electromagnetic pulse environment, a compact high voltage pulse generator was developed. The erected waveform with~1.6ns rise time, 42ns pulse width, 60kV peak value can be produced when this generator is connected to bounded-wave EMP simulator of the equivalent impedance of 120 ohms. Design considerations, system architecture, and experimental results of the generator are presented in this paper.%随着电磁武器的发展,核电磁脉冲及其工程防护技术受到各国的普遍关注。为模拟电磁脉冲环境,研制了一台紧凑型纳秒脉冲源,与有界波模拟器配合可产生的双指数波形前沿~1.6ns,脉宽42ns,幅值可达60kV。本文介绍了脉冲源的设计与调试结果。

  15. Plasma response to transient high voltage pulses

    Indian Academy of Sciences (India)

    S Kar; S Mukherjee

    2013-07-01

    This review reports on plasma response to transient high voltage pulses in a low pressure unmagnetized plasma. Mainly, the experiments are reviewed, when a disc electrode (metallic and dielectric) is biased pulsed negative or positive. The main aim is to review the electron loss in plasmas and particle balance during the negative pulse electrode biasing, when the applied pulse width is less than the ion plasma period. Though the applied pulse width is less than the ion plasma period, ion rarefaction waves are excited. The solitary electron holes are reviewed for positive pulsed bias to the electrode. Also the excitation of waves (solitary electron and ion holes) is reviewed for a metallic electrode covered by a dielectric material. The wave excitation during and after the pulse withdrawal, excitation and propagation characteristics of various electrostatic plasma waves are reviewed here.

  16. Central blood pressure and pulse wave velocity: relationship to target organ damage and cardiovascular morbidity-mortality in diabetic patients or metabolic syndrome. An observational prospective study. LOD-DIABETES study protocol

    Directory of Open Access Journals (Sweden)

    Castaño-Sánchez Carmen

    2010-03-01

    Full Text Available Abstract Background Diabetic patients show an increased prevalence of non-dipping arterial pressure pattern, target organ damage and elevated arterial stiffness. These alterations are associated with increased cardiovascular risk. The objectives of this study are the following: to evaluate the prognostic value of central arterial pressure and pulse wave velocity in relation to the incidence and outcome of target organ damage and the appearance of cardiovascular episodes (cardiovascular mortality, myocardial infarction, chest pain and stroke in patients with type 2 diabetes mellitus or metabolic syndrome. Methods/Design Design: This is an observational prospective study with 5 years duration, of which the first year corresponds to patient inclusion and initial evaluation, and the remaining four years to follow-up. Setting: The study will be carried out in the urban primary care setting. Study population: Consecutive sampling will be used to include patients diagnosed with type 2 diabetes between 20-80 years of age. A total of 110 patients meeting all the inclusion criteria and none of the exclusion criteria will be included. Measurements: Patient age and sex, family and personal history of cardiovascular disease, and cardiovascular risk factors. Height, weight, heart rate and abdominal circumference. Laboratory tests: hemoglobin, lipid profile, creatinine, microalbuminuria, glomerular filtration rate, blood glucose, glycosylated hemoglobin, blood insulin, fibrinogen and high sensitivity C-reactive protein. Clinical and 24-hour ambulatory (home blood pressure monitoring and self-measured blood pressure. Common carotid artery ultrasound for the determination of mean carotid intima-media thickness. Electrocardiogram for assessing left ventricular hypertrophy. Ankle-brachial index. Retinal vascular study based on funduscopy with non-mydriatic retinography and evaluation of pulse wave morphology and pulse wave velocity using the SphygmoCor system. The

  17. Molecular orientation via a dynamically induced pulse-train: Wave packet dynamics of NaI in a static electric field

    DEFF Research Database (Denmark)

    Marquetand, P.; Materny, A.; Henriksen, Niels Engholm;

    2004-01-01

    the charge separation is present, i.e., when the bond-length is large, a strong dipole moment exists and rotational excitation takes place. Upon bond contraction, the then covalently bound molecule does not experience the external field. This scenario repeats itself periodically. Thus, the vibrational...... dynamics causes a situation which is comparable to the interaction of the molecule with a train of pulses where the pulse separation is determined by the vibrational period. (C) 2004 American Institute of Physics....

  18. Pulse Wave Velocity for the Diagnosis of Pseudohypertension%脉搏波传导速度在假性高血压诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    胡静; 邓辉胜

    2011-01-01

    目的 采用踝臂脉搏波传导速度评价动脉硬化,为假性高血压诊断提供参考.方法 冠状动脉造影患者30例,造影结束后同步测量肱动脉内直接血压及间接血压各3次,计算直接血压与间接血压收缩压差值和直接血压与间接血压舒张压差值;并应用动脉硬化检测仪测定双侧踝臂脉搏波传导速度,并获得年龄、疾病、体质指数、血脂参数.根据收缩压差值或舒张压差值是否大于10 mmHg分为假性高血压组和非假性高血压组,对各项变量进行统计学分析.结果 两组间的年龄、性别比例、体质指数、吸烟史比例、冠心病比例、耱尿病比例、高脂血症比例、血脂水平相近,差异无统计学意义(P>0.05);脉压(P=0.001)、无创收缩压(P=0.018)、无创血压与直接血压差值差异均有统计学(P<0.05);假性高血压组患者脉搏波传导速度与非假性高血压组患者比较差异具有统计学意义(P=0.029).根据统计学操作者工作特征曲线得出踝臂脉搏波传导速度>1896.0 cm/s时,预测假性高血压具有最高的敏感度(80.0%)和特异度(73.3%).Pearson相关分析得出两者的Pearson相关系数为0.431,具有中等相关性.结论 根据踝臂脉搏波传导速度的异常可对假性高血压的诊断有参考价值.%Aim To assess the arteriosclerosis by pulse wave velocity (PWV) for providing a reference for the diagnosis of pseudohypertension. Methods Thirty inpatients (male 17, female 13) with coronary angiography whose ages were between 55 -85 years, were divided into two groups, one group was the pseudohypertension, the other was the comparison. The brachial artery blood pressure and the indirect blood pressure were measured three times simultaneously after coronary angiography, and the difference between direct and indirect systolic and diastolic blood pressure was calculated. The bilateral ankle-brachial PWV(BaPWV) were measured using the atherosclerosis detector and

  19. 脉冲平面波斜入射旋转对称体电磁散射的FDTD算法%FDTD Method for Electromagnetic Scattering by Body of Revolution with Obliquely Incident Pulse Plane Wave

    Institute of Scientific and Technical Information of China (English)

    关福宏; 陈彬; 陈海林; 方大纲; 俞文明; 张力军

    2007-01-01

    We present a method for electromagnetic scattering with obliquely incident pulse plane wave using BOR-FDTD(body of revolution finite-difference time-domain)method.The obliquely incident pulse plane wave is expanded in a cylindrical coordinate and a total-field/scattered-field formulation is introduced as excitation.The method is validated by comparing with the method of moments.It shows good agreement.%提出一种应用时域有限差分算法求解脉冲平面波斜入射时旋转对称体散射问题的方法.对斜入射脉冲平面波在圆柱坐标系下进行分解、应用总场/散射场连接边界、PML吸收边界条件.通过与矩量法分析结果的比较,验证了该方法的有效性.

  20. Research on Environmental Adaptability Design Method of Hot-wire EED under Pulse Electromagnetic Wave%电热火工品脉冲电磁波环境适应性设计方法研究

    Institute of Scientific and Technical Information of China (English)

    褚恩义; 白颖伟; 任炜; 程加奇

    2013-01-01

    In order to reduce the harm of pulse electromagnetic wave for hot-wire EED, the TVS diode was applied, and the protective circuit with certain function was designed. The test showed that TVS diode could release the induced energy and didn’t have obvious effect on the output of EED. This study provided an environmental adaptability design method for hot-wire EED under pulse electromagnetic wave.%为了衰减并有效防护脉冲电磁波对电热火工品的危害,采用TVS二极管,设计了具有特定功能的保护电路,用于脉冲电磁波危害的防护。测试结果表明,TVS二极管能较好地泄放电热火工品脉冲电磁波环境下的感应能量,并且对火工品的电爆输出性能无显著影响。本研究为电热火工品的抗电磁脉冲适应性设计提供了一种方法。