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Sample records for brachial-ankle pulse wave

  1. Brachial-ankle pulse wave velocity and symptomatic cerebral infarction in patients with type 2 diabetes: a cross-sectional study

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    Muramatsu Chie

    2003-08-01

    Full Text Available Abstract Background Recently a new automatic device that measures brachial-ankle pulse wave velocity using an oscillometric method has been developed. However, the practical significance of brachial-ankle pulse wave velocity measurement remains uncertain. The purpose of this study was to examine the association between brachial-ankle pulse wave velocity and symptomatic cerebral infarction in patients with type 2 diabetes. Methods One thousand sixty six patients with type 2 diabetes were studied cross-sectionally. Measurements of brachial-ankle pulse wave velocity were made using the automatic device. Logistic regression analysis was used to calculate the odds ratio for cerebral infarction. Results The presence of symptomatic cerebral infarction was confirmed in 86 patients. In these patients brachial-ankle pulse wave velocity was found to be significantly higher than in patients without cerebral infarction (18.94 ± 4.95 versus 16.46 ± 3.62 m/s, p Conclusion Overall, we conclude that an increase in brachial-ankle pulse wave velocity is associated with symptomatic cerebral infarction in patients with type 2 diabetes.

  2. Pitfalls in the ankle-brachial index and brachial-ankle pulse wave velocity

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    Ato D

    2018-04-01

    Full Text Available Dai Ato Gakujutsu Shien Co., Ltd., Tokyo, Japan Background: The ankle-brachial index (ABI and pulse wave velocity (PWV are indices of atherosclerosis and arterial stiffness. The Japan-made measuring devices of those indices have spread widely because of their convenience and the significance of the parameters. However, studies that comprehensively discuss the various pitfalls in using these indices are not available.Methods: This study presents several representative pitfalls in using the ABI and brachial-ankle PWV (baPWV by showing the result sheets of the device, “the Vascular Profiler”. Furthermore, some considerations when utilizing these indices in the future are also discussed.Results: Several diseases such as arteriosclerosis obliterans (ASO, arterial calcification in the lower limb, arterial stenosis in the right upper-limb, aortic valve diseases, arterial stenosis in the upper-limb of the contralateral side of the hemodialysis access, are the representative pitfalls when evaluating ABI and baPWV. Moreover, a measurement error is found to actually exist. Furthermore, same phenomena are considered most likely to occur when using other similar indices and devices.Conclusion: The ABI and baPWV are the useful and significant biomarkers. Nevertheless, caution is sometimes necessary when interpreting them. Moreover, rigorous patient exclusion criteria should be considered when using those indices in the severely conditioned patient population. And the results of this study can be applied to enhance the literacy using other indices, such as the cardio-ankle vascular index and other similar devices. Keywords: ankle-brachial index, pulse wave velocity, peripheral arterial disease, aortic valve disease, hemodialysis

  3. 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.

  4. Judgment value of brachial-ankle pulse wave velocity for lesion severity in hypertension patients with coronary arteriosclerosis

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    Zhong Zhao

    2016-07-01

    Full Text Available Objective: To analyze the judgment value of brachial-ankle pulse wave velocity for lesion severity in hypertension patients with coronary arteriosclerosis. Methods: A total of 100 cases of hypertension patients with coronary arteriosclerosis who received physical examination in Physical Examination Centre of our hospital were collected as research subjects of observation group, 100 cases patients with primary hypertension alone who received treatment in our hospital during the same period were selected as control group, brachial-ankle pulse wave velocity and ultrasound coronary area were detected, serum was collected to detect the levels of coronary arteriosclerosis illness-related indicators in it, and the judgment value of brachialankle pulse wave velocity for coronary arteriosclerosis severity was further analyzed. Results: PWV value of observation group was higher than that of control group while ABI value was lower than that of control group; intravascular ultrasound inspection showed that blood vessel volume, lumen volume and plaque volume of observation group were larger than those of control group; serum Hcy, Ox-LDL and ApoB/ApoA1 values of observation group were higher than those of control group while APN value was lower than that of control group; serum Lp-PLA2, sTWEAK, CML and bFGF values of observation group were higher than those of control group while secKlotho, Chrelin and MPO values were lower than those of control group; PWV and ABI values were directly correlated with disease severity-related factors. Conclusions: Brachial-ankle pulse wave velocity can effectively judge the lesion severity of hypertension patients with coronary arteriosclerosis, can be used as one of the accurate indicators to guide treatment and judge prognosis in clinical practice, and has important clinical value.

  5. [Relationship between brachial-ankle pulse wave velocity and metabolic syndrome].

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    Liu, Miao; He, Yao; Jiang, Bin; Wu, Lei; Wang, Jian-hua; Yang, Shan-shan; Wang, Yi-yan; Li, Xiao-ying

    2014-06-18

    To evaluate the association between brachial-ankle pulse wave velocity (ba-PWV) and metabolic syndrome (MetS) among the Chinese elderly and the gender difference. We conducted a population-based cross-sectional study in a representative urban area of Beijing, China. A sample of 2 102 community elderly (848 males, and 1 254 females) aged 60 to 95 years were included in the study. MetS was defined according to the 2009 harmonizing definition. The prevalence of MetS was 59.1% (50.1% in males and 65.2% in females, P<0.001). The baPWV value was between 8.2 to 45.6 (20.0 ± 4.4) m/s, and showed an increasing trend with age (P<0.001). The partial correlation showed baPWV was positively associated with BMI (r=0.076, P=0.037), systolic blood pressure (r=0.380, P<0.001), diastolic blood pressure (r=0.276, P<0.001), triglyceride (r=0.040, P=0.046), fasting blood glucose (r=0.140, P<0.001), 2-hour post-meal blood glucose (r=0.121, P<0.001), and negatively associated with HDL-C (r=-0.128, P=0.048). There was a strong association between baPWV and prevalence of MetS and its component number in females but not in males. Compared with the lowest quartile of baPWV, the adjusted ORs were 1.22 (95%CI 0.83-1.79), 1.32 (95%CI 0.90-1.93), 1.46(95%CI 1.00-2.14) in males and 1.28 (95%CI 0.93-1.77), 1.55 (95%CI 1.12-2.16), 1.86(95%CI 1.32-2.61) in females for the second, third and top quartiles. The prevalence of MetS increases substantially with increasing levels of baPWV among the Chinese elderly, especially in females.

  6. Genetically elevated levels of circulating triglycerides and brachial-ankle pulse wave velocity in a Chinese population.

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    Yao, W-M; Zhang, H-F; Zhu, Z-Y; Zhou, Y-L; Liang, N-X; Xu, D-J; Zhou, F; Sheng, Y-H; Yang, R; Gong, L; Yin, Z-J; Chen, F-K; Cao, K-J; Li, X-L

    2013-04-01

    Elevated levels of circulating triglycerides and increased arterial stiffness are associated with cardiovascular disease. Numerous studies have reported an association between levels of circulating triglycerides and arterial stiffness. We used Mendelian randomization to test whether this association is causal. We investigated the association between circulating triglyceride levels, the apolipoprotein A-V (ApoA5) -1131T>C single nucleotide polymorphism and brachial-ankle pulse wave velocity (baPWV) by examining data from 4421 subjects aged 18-74 years who were recruited from the Chinese population. baPWV was significantly associated with the levels of circulating triglycerides after adjusting for age, sex, body mass index (BMI), systolic blood pressure, heart rate, waist-to-hip ratio, antihypertensive treatment and diabetes mellitus status. The -1131C allele was associated with a 5% (95% confidence interval 3-8%) increase in circulating triglycerides (adjusted for age, sex, BMI, waist-to-hip ratio, diabetes mellitus and antihypertensive treatment). Instrumental variable analysis showed that genetically elevated levels of circulating triglycerides were not associated with increased baPWV. These results do not support the hypothesis that levels of circulating triglycerides have a causal role in the development of arterial stiffness.

  7. Relation between respiratory function and arterial stiffness assessed using brachial-ankle pulse wave velocity in healthy workers.

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    Inomoto, Atsushi; Fukuda, Rika; Deguchi, Junko; Toyonaga, Toshihiro

    2017-09-01

    [Purpose] Current studies report that patients with chronic obstructive pulmonary disease (COPD) may also have arteriosclerosis. This study aimed to investigate the relationship between respiratory function and arterial stiffness in healthy workers using the brachial-ankle pulse wave velocity (baPWV). [Subjects and Methods] This study included 104 male Japanese workers without COPD. We collected participant information and measured hemodynamics, body composition, and respiratory function. [Results] In the correlation analysis, baPWV showed a significant positive correlation with age, smoking index, systolic blood pressure, diastolic blood pressure, and heart rate, and a significant negative correlation with height, fat free mass, lower limb muscle mass, forced vital capacity (FVC), and forced expiratory volume in one second (FEV1). In multiple regression analysis using factors other than baPWV and respiratory function as adjustment variables, both FVC and FEV1 showed a significant negative relationship with baPWV (p=0.009 and p=0.027, respectively). FEV1/FVC was not significantly related to baPWV (p=0.704). [Conclusion] The results of this study indicated that FEV1/FVC and the proportion of FEV1 predicted, which are indicators of airflow limitation, are not predictors of baPWV in workers without airflow limitation. However, since baPWV showed a significant negative relationship with FVC and FEV 1, the reduction in respiratory function that does not cause airflow limitation, such as FVC or FEV1 decline, may be related to an increase in the risk of arterial stiffness.

  8. Impaired left ventricular systolic function and increased brachial-ankle pulse-wave velocity are independently associated with rapid renal function progression.

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    Chen, Szu-Chia; Lin, Tsung-Hsien; Hsu, Po-Chao; Chang, Jer-Ming; Lee, Chee-Siong; Tsai, Wei-Chung; Su, Ho-Ming; Voon, Wen-Chol; Chen, Hung-Chun

    2011-09-01

    Heart failure and increased arterial stiffness are associated with declining renal function. Few studies have evaluated the association between left ventricular ejection fraction (LVEF) and brachial-ankle pulse-wave velocity (baPWV) and renal function progression. The aim of this study was to assess whether LVEFfunction was estimated by eGFR slope. The renal end point was defined as ≥25% decline in eGFR. Clinical and echocardiographic parameters were compared and analyzed. After a multivariate analysis, serum hematocrit was positively associated with eGFR slope, and diabetes mellitus, baPWV (P=0.031) and LVEFfunction decline and progression to the renal end point.

  9. 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

  10. Association between the severity of coronary artery stenosis and the combination of the difference in blood pressure between arms and brachial-ankle pulse wave velocity.

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    Miyase, Yuiko; Miura, Shin-Ichiro; Shiga, Yuhei; Yano, Masaya; Suematsu, Yasunori; Adachi, Sen; Norimatsu, Kenji; Nakamura, Ayumi; Saku, Keijiro

    2016-01-01

    A difference in systolic blood pressure (SBP) ≥10 mmHg between the arms is associated with an increased risk of coronary artery disease (CAD) and mortality in high-risk patients. Four hundred and fourteen patients were divided into three groups according to the percent most severe luminal narrowing of a coronary artery as diagnosed by coronary computed tomography angiography: no or mild coronary stenosis (0-49%), moderate stenosis (50-69%) and severe stenosis (≥70%) groups. The relative difference in SBP between arms in the severe group was significantly lower than those in the no or mild and moderate groups. The brachial-ankle pulse wave velocity (baPWV) significantly increased as the severity of coronary stenosis increased. We confirmed that severe coronary stenosis was independently associated with both the relative difference in SBP between arms and baPWV, in addition to age, gender, hypertension, dyslipidemia, diabetes mellitus and ankle-brachial index by a logistic regression analysis. The group with a relative difference in SBP between arms of difference in SBP between arms and baPWV may be a more effective approach for the non-invasive assessment of the severity of CAD.

  11. Plasma Renalase is Not Associated with Blood Pressure and Brachial-Ankle Pulse Wave Velocity in Chinese Adults With Normal Renal Function

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    Yang Wang

    2016-11-01

    Full Text Available Background/Aims: This study aimed to investigate the association of renalase with blood pressure (BP and brachial-ankle pulse wave velocity (baPWV in order to better understand the role of renalase in the pathogenesis of hypertension and atherosclerosis. Methods: A total of 344 subjects with normal kidney function were recruited from our previously established cohort in Shaanxi Province, China. They were divided into the normotensive (NT and hypertensive (HT groups or high baPWV and normal baPWV on the basis of BP levels or baPWV measured with an automatic waveform analyzer. Plasma renalase was determined through an enzyme-linked immunosorbent assay. Results: Plasma renalase did not significantly differ between HT and NT groups (3.71 ± 0.69 µg/mL vs. 3.72 ± 0.73 μg/mL, P = 0.905 and between subjects with and without high baPWV (3.67 ± 0.66 µg/mL vs. 3.73 ± 0.74 µg/mL, P = 0.505. However, baPWV was significantly higher in the HT group than in the NT group (1460.4 ± 236.7 vs. 1240.7 ± 174.5 cm/s, P Conclusion: Plasma renalase may not be associated with BP and baPWV in Chinese subjects with normal renal function.

  12. Brachial-ankle pulse wave velocity predicts decline in renal function and cardiovascular events in early stages of chronic kidney disease.

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    Yoon, Hye Eun; Shin, Dong Il; Kim, Sung Jun; Koh, Eun Sil; Hwang, Hyeon Seok; Chung, Sungjin; Shin, Seok Joon

    2013-01-01

    In this study, we investigated the predictive capacity of the brachial-ankle aortic pulse wave velocity (baPWV), a marker of arterial stiffness, for the decline in renal function and for cardiovascular events in the early stages of chronic kidney disease (CKD). Two hundred forty-one patients who underwent a comprehensive check-up were included and were divided into two groups according to their estimated glomerular filtration rates (eGFR): patients with CKD categories G2, G3a and G3b (30 ≤ eGFR function, the eGFR change, was determined by the slope of eGFR against time. We analysed whether baPWV was associated with eGFR change or predicted cardiovascular events. baPWV was independently associated with eGFR change in a multivariate analysis of the total patients (β=-0.011, p=0.011) and remained significantly associated with eGFR change in a subgroup analysis of the eGFR function and short-term cardiovascular events.

  13. Plasma Renalase is Not Associated with Blood Pressure and Brachial-Ankle Pulse Wave Velocity in Chinese Adults With Normal Renal Function.

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    Wang, Yang; Lv, Yong-Bo; Chu, Chao; Wang, Man; Xie, Bing-Qing; Wang, Lan; Yang, Fan; Yan, Ding-Yi; Yang, Rui-Hai; Yang, Jun; Ren, Yong; Yuan, Zu-Yi; Mu, Jian-Jun

    2016-01-01

    This study aimed to investigate the association of renalase with blood pressure (BP) and brachial-ankle pulse wave velocity (baPWV) in order to better understand the role of renalase in the pathogenesis of hypertension and atherosclerosis. A total of 344 subjects with normal kidney function were recruited from our previously established cohort in Shaanxi Province, China. They were divided into the normotensive (NT) and hypertensive (HT) groups or high baPWV and normal baPWV on the basis of BP levels or baPWV measured with an automatic waveform analyzer. Plasma renalase was determined through an enzyme-linked immunosorbent assay. Plasma renalase did not significantly differ between HT and NT groups (3.71 ± 0.69 µg/mL vs. 3.72 ± 0.73 μg/mL, P = 0.905) and between subjects with and without high baPWV (3.67 ± 0.66 µg/mL vs. 3.73 ± 0.74 µg/mL, P = 0.505). However, baPWV was significantly higher in the HT group than in the NT group (1460.4 ± 236.7 vs. 1240.7 ± 174.5 cm/s, P function. © 2016 The Author(s) Published by S. Karger AG, Basel.

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

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    Ting Li

    2017-01-01

    Full Text Available The incidence of ischemic stroke in patients with diabetes is increasing. While brachial-ankle pulse wave velocity (BaPWV and ankle-brachial index (ABI are known to be associated with ischemic cardiovascular and cerebrovascular diseases, whether these measures predict the risk of ischemic cerebrovascular disease in diabetic patients remains unclear. 117 patients with type 2 diabetes were enrolled in this study. According to the results of head magnetic resonance imaging, the patients were divided into a diabetes-only group (n = 55 and a diabetes and ischemic stroke group (n = 62. We then performed ABI and BaPWV examinations for all patients. Compared with the diabetes-only group, we found decreased ABI and increased BaPWV in the diabetes and ischemic stroke group. Multivariate logistic regression analyses revealed that BaPWV and ABI were risk factors for ischemic stroke in patients with type 2 diabetes. Our findings indicate that decreased ABI and increased BaPWV are objective indicators of increased risk of ischemic stroke in patients with type 2 diabetes.

  15. Brachial-ankle pulse wave velocity is associated with coronary calcium in young and middle-aged asymptomatic adults: The Kangbuk Samsung Health Study.

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    Cainzos-Achirica, Miguel; Rampal, Sanjay; Chang, Yoosoo; Ryu, Seungho; Zhang, Yiyi; Zhao, Di; Cho, Juhee; Choi, Yuni; Pastor-Barriuso, Roberto; Lim, So Yeon; Bruguera, Jordi; Elosua, Roberto; Lima, Joao A C; Shin, Hocheol; Guallar, Eliseo

    2015-08-01

    To evaluate the association between brachial-ankle pulse wave velocity (baPWV), a convenient, non-radiating, readily available measurement of arterial stiffness, and coronary artery calcium (CAC), a reliable marker of coronary atherosclerosis, in a large sample of young and middle-aged asymptomatic adults; and to assess the incremental value of baPWV for detecting prevalent CAC beyond traditional risk factors. Cross-sectional study of 15,185 asymptomatic Korean adults who voluntarily underwent a comprehensive health screening program including measurement of baPWV and CAC. BaPWV was measured using an oscillometric method with cuffs placed on both arms and ankles. CAC burden was assessed using a multi-detector CT scan and scored following Agatston's method. The prevalence of CAC > 0 and CAC > 100 increased across baPWV quintiles. The multivariable-adjusted odds ratios (95% CI) for CAC > 0 comparing baPWV quintiles 2-5 versus quintile 1 were 1.06 (0.87-1.30), 1.24 (1.02-1.50), 1.39 (1.15-1.69) and 1.60 (1.31-1.96), respectively (P trend  100 were 1.30 (0.74-2.26), 1.59 (0.93-2.71), 1.74 (1.03-2.94) and 2.59 (1.54-4.36), respectively (P trend  100, the area under the ROC curve for baPWV alone was 0.71 (0.68-0.74), and the addition of baPWV to traditional risk factors significantly improved the discrimination and calibration of models for detecting prevalent CAC > 0 and CAC > 100. BaPWV was independently associated with the presence and severity of CAC in a large sample of young and middle-aged asymptomatic adults. BaPWV may be a valuable tool for identifying apparently low-risk individuals with increased burden of coronary atherosclerosis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  16. [Relationship between brachial-ankle pulse wave velocity and glycemic control of type 2 diabetes mellitus patients in Beijing community population].

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    Sun, Ke-xin; Liu, Zhi-ke; Cao, Ya-ying; Juan, Juan; Xiang, Xiao; Yang, Cheng; Huang, Shao-ping; Liu, Xiao-fen; Li, Na; Tang, Xun; Li, Jin; Wu, Tao; Chen, Da-fang; Hu, Yong-hua

    2015-06-18

    To explore the correlation between glycemic control of type 2 diabetes mellitus (T2DM) patients and brachial-ankle pulse velocity (baPWV). A community-based cross-sectional study was conducted in Beijing, China. Every subject underwent physical examinations, glycated hemoglobin (HbA1c), blood lipid and baPWV measurements and completed a standardized questionnaire. T2DM patients were divided into well controlled and poorly controlled groups according to HbA1c levels. The correlation between glycemic control of T2DM patients and baPWV was analyzed. In this study, 1 341 subjects were recruited, including 733 T2DM patients and 608 non-diabetes subjects. Compared with non-diabetes subjects, abnormal baPWV (baPWV≥1 700 cm/s) rate for T2DM patients was higher (40.8% vs. 26.8%, Pcontrol in T2DM patients, the abnormal baPWV rates for non-diabetes subjects, well controlled and poorly controlled T2DM patients were significantly different (non-diabetes vs. HbA1ccontrol status of T2DM patients was associated with abnormal baPWV. Compared with non-diabetes subjects, the ORs for abnormal baPWV in HbA1ccontrol status of T2DM patients from communities is significantly associated with baPWV. Poor glycemic control is a risk factor for abnormal baPWV. Keeping HbA1c under control might lower the risk of cardiovascular diseases in T2DM patients.

  17. Impact of a systolic parameter, defined as the ratio of right brachial pre-ejection period to ejection time, on the relationship between brachial-ankle pulse wave velocity and left ventricular diastolic function.

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    Hsu, Po-Chao; Lin, Tsung-Hsien; Lee, Chee-Siong; Chu, Chun-Yuan; Su, Ho-Ming; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung

    2011-04-01

    Arterial stiffness is correlated with left ventricular (LV) diastolic function as well as susceptibility to LV systolic function. Therefore, if LV systolic function is not known, the relationship between arterial stiffness and LV diastolic function is difficult to determine. A total of 260 patients were included in the study. The brachial-ankle pulse wave velocity (baPWV) and the ratio of right brachial pre-ejection period to ejection time (rbPEP/rbET) were measured using an ABI-form device. Patients were classified into four groups. Groups 1, 2, 3 and 4 were patients with rbPEP/rbET and baPWV below the median, rbPEP/rbET above but baPWV below the median, rbPET/rbET below but baPWV above the median, and rbPET/rbET and baPWV above the median, respectively. The LV ejection fractions in groups 1 and 3 were higher than those in groups 2 and 4 (Pwave velocity to Ea that were comparable to those in groups 3 and 4. In conclusion, rbPEP/rbET had an impact on the relationship between baPWV and LV diastolic function. In patients with high rbPEP/rbET but low baPWV, low baPWV may not indicate good LV diastolic function but implies that cardiac dysfunction may precede vascular dysfunction in such patients. When interpreting the relationship between baPWV and LV diastolic function, the rbPEP/rbET value obtained from the same examination should be considered.

  18. Association of pulse wave velocity and pulse pressure with decline in kidney function.

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    Kim, Chang Seong; Kim, Ha Yeon; Kang, Yong Un; Choi, Joon Seok; Bae, Eun Hui; Ma, Seong Kwon; Kim, Soo Wan

    2014-05-01

    The association between arterial stiffness and decline in kidney function in patients with mild to moderate chronic kidney disease (CKD) is not well established. This study investigated whether pulse wave velocity (PWV) and pulse pressure (PP) are independently associated with glomerular filtration rate (GFR) and rapid decline in kidney function in early CKD. Carotid femoral PWV (cfPWV), brachial-ankle PWV (baPWV), and PP were measured in a cohort of 913 patients (mean age, 63±10 years; baseline estimated GFR, 84±18 mL/min/1.73 m(2) ). Estimated GFR was measured at baseline and at follow-up. The renal outcome examined was rapid decline in kidney function (estimated GFR loss, >3 mL/min/1.73 m(2) per year). The median follow-up duration was 3.2 years. Multivariable adjusted linear regression model indicated that arterial PWV (both cfPWV and baPWV) and PP increased as estimated GFR declined, but neither was associated with kidney function after adjustment for various covariates. Multivariable logistic regression analysis found that cfPWV and baPWV were not associated with rapid decline in kidney function (odds ratio [OR], 1.39, 95% confidence interval [CI], 0.41-4.65; OR, 2.51, 95% CI, 0.66-9.46, respectively), but PP was (OR, 1.22, 95% CI, 1.01-1.48; P=.045). Arterial stiffness assessed using cfPWV and baPWV was not correlated with lower estimated GFR and rapid decline in kidney function after adjustment for various confounders. Thus, PP is an independent risk factor for rapid decline in kidney function in populations with relatively preserved kidney function (estimated GFR ≥30 mL/min/1.73 m(2) ). ©2014 Wiley Periodicals, Inc.

  19. Acoustic radiation force impulse elastography of the kidneys: is shear wave velocity affected by tissue fibrosis or renal blood flow?

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    Asano, Kenichiro; Ogata, Ai; Tanaka, Keiko; Ide, Yoko; Sankoda, Akiko; Kawakita, Chieko; Nishikawa, Mana; Ohmori, Kazuyoshi; Kinomura, Masaru; Shimada, Noriaki; Fukushima, Masaki

    2014-05-01

    The aim of this study was to identify the main influencing factor of the shear wave velocity (SWV) of the kidneys measured by acoustic radiation force impulse elastography. The SWV was measured in the kidneys of 14 healthy volunteers and 319 patients with chronic kidney disease. The estimated glomerular filtration rate was calculated by the serum creatinine concentration and age. As an indicator of arteriosclerosis of large vessels, the brachial-ankle pulse wave velocity was measured in 183 patients. Compared to the degree of interobserver and intraobserver deviation, a large variance of SWV values was observed in the kidneys of the patients with chronic kidney disease. Shear wave velocity values in the right and left kidneys of each patient correlated well, with high correlation coefficients (r = 0.580-0.732). The SWV decreased concurrently with a decline in the estimated glomerular filtration rate. A low SWV was obtained in patients with a high brachial-ankle pulse wave velocity. Despite progression of renal fibrosis in the advanced stages of chronic kidney disease, these results were in contrast to findings for chronic liver disease, in which progression of hepatic fibrosis results in an increase in the SWV. Considering that a high brachial-ankle pulse wave velocity represents the progression of arteriosclerosis in the large vessels, the reduction of elasticity succeeding diminution of blood flow was suspected to be the main influencing factor of the SWV in the kidneys. This study indicates that diminution of blood flow may affect SWV values in the kidneys more than the progression of tissue fibrosis. Future studies for reducing data variance are needed for effective use of acoustic radiation force impulse elastography in patients with chronic kidney disease.

  20. Association between Pulse Wave Velocity and Coronary Artery Calcification in Japanese men.

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    Torii, Sayuki; Arima, Hisatomi; Ohkubo, Takayoshi; Fujiyoshi, Akira; Kadota, Aya; Takashima, Naoyuki; Kadowaki, Sayaka; Hisamatsu, Takashi; Saito, Yoshino; Miyagawa, Naoko; Zaid, Maryam; Murakami, Yoshitaka; Abbott, Robert D; Horie, Minoru; Miura, Katsuyuki; Ueshima, Hirotsugu

    2015-01-01

    Pulse wave velocity (PWV) is a simple and valid clinical method for assessing arterial stiffness. Coronary artery calcification (CAC) is an intermediate stage in the process leading to overt cardiovascular disease (CVD) and an established determinant of coronary artery disease. This study aimed to examine the association between PWV and CAC in a population-based sample of Japanese men. This is a cross-sectional study of 986 randomly selected men aged 40-79 years from Shiga, Japan. CVD-free participants were examined from 2006 to 2008. Brachial-ankle PWV (baPWV) was measured using an automatic waveform analyzer. CAC was assessed using computed tomography. Agatston scores ≥ 10 were defined as the presence of CAC. Prevalence of CAC progressively increased with rising levels of baPWV: 20.6%, 41.7%, 56.3%, and 66.7% across baPWV quartiles < 1378, 1378-1563, 1564-1849, and > 1849 cm/s (P < 0.001 for trend). Associations remained significant after adjusting for age and other factors, including body mass index, systolic blood pressure, pulse rate, total and high-density lipoprotein cholesterol, hemoglobin A1c, drinking, smoking and exercise status, and the use of medication to treat hypertension, dyslipidemia and diabetes (P=0.042 for trend). The optimal cutoff level of baPWV to detect CAC was 1612 cm/s using receiver operating characteristic curve analysis. Arterial stiffness as defined by an elevated baPWV is associated with an increased prevalence of CAC in a general population-based setting among Japanese men.

  1. Ageing and Pulse Wave Velocity in Relation to Serum Nitric Oxide

    Directory of Open Access Journals (Sweden)

    Jyoti P. Khodnapur

    2018-01-01

    Full Text Available Background: The Pulse Wave Velocity (PWV is an important marker of arterial stiffness. Age related changes of arterial stiffness in relation to PWV and endothelial derived Nitric Oxide (NOx are least explored. Aim and Objectives: The present study was aimed to assess a relationship between age associated vascular stiffness and endothelial derived nitric oxide in both males and females. Materials and Methods: One hundred twenty healthy subjects male (n= 60 and female (n=60 subjects (20 to 95 years were randomly selected among general population of Vijayapur city, Karnataka. Subjects were divided into group I (20-29 years, II (30-39 years, III (40-49 years, IV (50-59 years, V (60-69 years and VI (>70 years. Physiological parameters like blood pressure and endothelial derived NOx were assessed. Vascular stiffness parameter like brachial-ankle PWV(b-aPWV and carotid femoral PWV (c-fPWV were also evaluated. Statistical analysis was done by using one way ANOVA and post hoc t test by using SPSS software. Results: Group I to group VI showed significant steady increase of b-a PWV and c-f PWV with concomitant significant decrease of serum NOx in both male and female subjects. Further a significant negative correlation between b-aPWV and c-f PWV with NOx in both male and female subjects were also observed. Conclusion: Results suggested possible influences of ageing on vascular stiffness which may be due to alteration of endothelial derived NOx.

  2. Sequentially pulsed traveling wave accelerator

    Science.gov (United States)

    Caporaso, George J [Livermore, CA; Nelson, Scott D [Patterson, CA; Poole, Brian R [Tracy, CA

    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.

  3. Age-Specific Determinants of Pulse Wave Velocity among Metabolic Syndrome Components, Inflammatory Markers, and Oxidative Stress.

    Science.gov (United States)

    Kim, Minkyung; Kim, Minjoo; Yoo, Hye Jin; Lee, Seung Yeon; Lee, Sang-Hyun; Lee, Jong Ho

    2018-02-01

    Pulse wave velocity (PWV) is thought to have different relationships with metabolic syndrome (MS) components, inflammatory markers, and oxidative stress, according to age. However, age-specific determinants of PWV have not yet been studied. We investigated age-dependent relationships among PWV and MS components, inflammatory markers, and oxidative stress. A total of 4,318 subjects were divided into 4 groups: 19-34 y (n=687), 35-44 y (n=1,413), 45-54 y (n=1,384), and 55-79 y (n=834). MS components, brachial-ankle PWV (baPWV), high-sensitivity C-reactive protein (hs-CRP), and oxidative stress markers were measured. There were age-related increases in MS, body mass index (BMI), waist circumference, systolic blood pressure (SBP), diastolic BP (DBP), triglycerides, glucose, hs-CRP, oxidized low-density lipoprotein (LDL), 8-epi-prostaglandin F 2α (8-epi-PGF 2α ), and baPWV. BaPWV was significantly associated with sex and elevated BP in the 19-34 y group; with age, sex, BMI, elevated BP and triglycerides in the 35-44 y group; with age, sex, elevated BP, fasting glucose, hs-CRP and oxidized LDL in the 45-54 y group; and with age, BMI, elevated BP, fasting glucose and oxidized LDL in the 55-79 y group. Our results show that age-related increases in baPWV are associated with age-related changes in MS components, inflammatory markers, and oxidative stress. However, each of these factors has an age-specific, different impact on arterial stiffness. In particular, oxidative stress may be independently associated with arterial stiffness in individuals older than 45 y.

  4. Wave equations for pulse propagation

    International Nuclear Information System (INIS)

    Shore, B.W.

    1987-01-01

    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. The memo discusses various ways of characterizing the polarization characteristics of plane waves, that is, of parameterizing a transverse unit vector, such as the Jones vector, the Stokes vector, and the Poincare sphere. It discusses the connection between macroscopically defined quantities, such as the intensity or, more generally, the Stokes parameters, and microscopic field amplitudes. The material presented here is a portion of a more extensive treatment of propagation to be presented separately. The equations presented here have been described in various books and articles. They are collected here as a summary and review of theory needed when treating pulse propagation

  5. Pulse-wave morphology and pulse-wave velocity in healthy human volunteers

    DEFF Research Database (Denmark)

    Frimodt-Møller, M; Nielsen, A H; Kamper, A-L

    2006-01-01

    as smoking caused significant changes in both PWA and PWV parameters and an inter-arm difference was observed. Intra- and interobserver reproducibility was good. CONCLUSIONS: Pulse-wave measurements by applanation tonometry should be undertaken in the same arm during fasting and smoking abstinence.......OBJECTIVE: Applanation tonometry for pulse-wave analysis (PWA) and determination of pulse-wave velocity (PWV) is a non-invasive method for assessment of the central aortic pressure waveform and indices of arterial stiffness. The objective of this study was to examine the influence of eating...... and smoking on PWA and PWV measurements in order to establish standard examination conditions. Furthermore, intra- and interobserver reproducibility and the effects of varying the site of measurements were observed. MATERIAL AND METHODS: Duplicate measurements of the radial pressure waveform...

  6. Multiple pulse traveling wave excitation of neon-like germanium

    International Nuclear Information System (INIS)

    Moreno, J. C.; Nilsen, J.; Silva, L. B. da

    1995-01-01

    Traveling wave excitation has been shown to significantly increase the output intensity of the neon-like germanium x-ray laser. The driving laser pulse consisted of three 100 ps Gaussian laser pulses separated by 400 ps. Traveling wave excitation was employed by tilting the wave front of the driving laser by 45 degrees to match the propagation speed of the x-ray laser photons along the length of the target. We show results of experiments with the traveling wave, with no traveling wave, and against the traveling wave and comparisons to a numerical model. Gain was inferred from line intensity measurements at two lengths

  7. Spectrally modified chirped pulse generation of sustained shock waves

    International Nuclear Information System (INIS)

    McGrane, S.D.; Moore, D.S.; Funk, D.J.; Rabie, R.L.

    2002-01-01

    A method is described for generating shock waves with 10-20 ps risetime followed by >200 ps constant pressure, using spectrally modified (clipped) chirped laser pulses. The degree of spectral clipping alters the chirped pulse temporal intensity profile and thereby the time-dependent pressure (tunable via pulse energy) generated in bare and nitrocellulose-coated Al thin films. The method is implementable in common chirped amplified lasers, and allows synchronous probing with a <200 fs pulse

  8. Threshold value of home pulse pressure predicting arterial stiffness in patients with type 2 diabetes: KAMOGAWA-HBP study.

    Science.gov (United States)

    Kitagawa, Noriyuki; Ushigome, Emi; Matsumoto, Shinobu; Oyabu, Chikako; Ushigome, Hidetaka; Yokota, Isao; Asano, Mai; Tanaka, Muhei; Yamazaki, Masahiro; Fukui, Michiaki

    2018-03-01

    This cross-sectional multicenter study was designed to evaluate the threshold value of home pulse pressure (PP) and home systolic blood pressure (SBP) predicting the arterial stiffness in 876 patients with type 2 diabetes. We measured the area under the receiver-operating characteristic curve (AUC) and estimated the ability of home PP to identify arterial stiffness using Youden-Index defined cut-off point. The arterial stiffness was measured using the brachial-ankle pulse wave velocity (baPWV). AUC for arterial stiffness in morning PP was significantly greater than that in morning SBP (P AUC for arterial stiffness in evening PP was also significantly greater than that in evening SBP (P < .001). The optimal cut-off points for morning PP and evening PP, which predicted arterial stiffness, were 54.6 and 56.9 mm Hg, respectively. Our findings indicate that we should pay more attention to increased home PP in patients with type 2 diabetes. ©2018 Wiley Periodicals, Inc.

  9. Comparison of Regression Analysis and Transfer Function in Estimating the Parameters of Central Pulse Waves from Brachial Pulse Wave.

    Science.gov (United States)

    Chai, Rui; Xu, Li-Sheng; Yao, Yang; Hao, Li-Ling; Qi, Lin

    2017-01-01

    This study analyzed ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO), and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. Invasively measured parameters were compared with parameters measured from brachial pulse waves by regression model and transfer function model. Accuracy of parameters estimated by regression and transfer function model, was compared too. Findings showed that k value, central pulse wave and brachial pulse wave parameters invasively measured, correlated positively. Regression model parameters including A_slope, DBP, SEVR, and transfer function model parameters had good consistency with parameters invasively measured. They had same effect of consistency. SBP, PP, SV, and CO could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

  10. Regression analysis and transfer function in estimating the parameters of central pulse waves from brachial pulse wave.

    Science.gov (United States)

    Chai Rui; Li Si-Man; Xu Li-Sheng; Yao Yang; Hao Li-Ling

    2017-07-01

    This study mainly analyzed the parameters such as ascending branch slope (A_slope), dicrotic notch height (Hn), diastolic area (Ad) and systolic area (As) diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP), subendocardial viability ratio (SEVR), waveform parameter (k), stroke volume (SV), cardiac output (CO) and peripheral resistance (RS) of central pulse wave invasively and non-invasively measured. These parameters extracted from the central pulse wave invasively measured were compared with the parameters measured from the brachial pulse waves by a regression model and a transfer function model. The accuracy of the parameters which were estimated by the regression model and the transfer function model was compared too. Our findings showed that in addition to the k value, the above parameters of the central pulse wave and the brachial pulse wave invasively measured had positive correlation. Both the regression model parameters including A_slope, DBP, SEVR and the transfer function model parameters had good consistency with the parameters invasively measured, and they had the same effect of consistency. The regression equations of the three parameters were expressed by Y'=a+bx. The SBP, PP, SV, CO of central pulse wave could be calculated through the regression model, but their accuracies were worse than that of transfer function model.

  11. Surface-Wave Pulse Routing around Sharp Right Angles

    Science.gov (United States)

    Gao, Z.; Xu, H.; Gao, F.; Zhang, Y.; Luo, Y.; Zhang, B.

    2018-04-01

    Surface-plasmon polaritons (SPPs), or localized electromagnetic surface waves propagating on a metal-dielectric interface, are deemed promising information carriers for future subwavelength terahertz and optical photonic circuitry. However, surface waves fundamentally suffer from scattering loss when encountering sharp corners in routing and interconnection of photonic signals. Previous approaches enabling scattering-free surface-wave guidance around sharp corners are limited to either volumetric waveguide environments or extremely narrow bandwidth, being unable to guide a surface-wave pulse (SPP wave packet) on an on-chip platform. Here, in a surface-wave band-gap crystal implemented on a single metal surface, we demonstrate in time-domain routing a surface-wave pulse around multiple sharp right angles without perceptible scattering. Our work not only offers a solution to on-chip surface-wave pulse routing along an arbitrary path, but it also provides spatiotemporal information on the interplay between surface-wave pulses and sharp corners, both of which are desirable in developing high-performance large-scale integrated photonic circuits.

  12. Rotary wave-ejector enhanced pulse detonation engine

    Science.gov (United States)

    Nalim, M. R.; Izzy, Z. A.; Akbari, P.

    2012-01-01

    The use of a non-steady ejector based on wave rotor technology is modeled for pulse detonation engine performance improvement and for compatibility with turbomachinery components in hybrid propulsion systems. The rotary wave ejector device integrates a pulse detonation process with an efficient momentum transfer process in specially shaped channels of a single wave-rotor component. In this paper, a quasi-one-dimensional numerical model is developed to help design the basic geometry and operating parameters of the device. The unsteady combustion and flow processes are simulated and compared with a baseline PDE without ejector enhancement. A preliminary performance assessment is presented for the wave ejector configuration, considering the effect of key geometric parameters, which are selected for high specific impulse. It is shown that the rotary wave ejector concept has significant potential for thrust augmentation relative to a basic pulse detonation engine.

  13. Pulsed lower-hybrid wave penetration in reactor plasmas

    International Nuclear Information System (INIS)

    Cohen, R.H.; Bonoli, P.T.; Porkolab, M.; Rognlien, T.D.

    1989-01-01

    Providing lower-hybrid power in short, intense (GW) pulses allows enhanced wave penetration in reactor-grade plasmas. We examine nonlinear absorption, ray propagation, and parametric instability of the intense pulses. We find that simultaneously achieving good penetration while avoiding parametric instabilities is possible, but imposes restrictions on the peak power density, pulse duration, and/or r.f. spot shape. In particular, power launched in narrow strips, elongated along the field direction, is desired

  14. Estimated carotid-femoral pulse wave velocity has similar predictive value as measured carotid-femoral pulse wave velocity

    DEFF Research Database (Denmark)

    Greve, Sara V; Blicher, Marie K; Kruger, Ruan

    2016-01-01

    BACKGROUND: Carotid-femoral pulse wave velocity (cfPWV) adds significantly to traditional cardiovascular risk prediction, but is not widely available. Therefore, it would be helpful if cfPWV could be replaced by an estimated carotid-femoral pulse wave velocity (ePWV) using age and mean blood pres...... that these traditional risk scores have underestimated the complicated impact of age and blood pressure on arterial stiffness and cardiovascular risk....

  15. Traveling waves of the regularized short pulse equation

    International Nuclear Information System (INIS)

    Shen, Y; Horikis, T P; Kevrekidis, P G; Frantzeskakis, D J

    2014-01-01

    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)

  16. Estimated carotid-femoral pulse wave velocity has similar predictive value as measured carotid-femoral pulse wave velocity

    DEFF Research Database (Denmark)

    Olsen, Michael; Greve, Sara; Blicher, Marie

    2016-01-01

    OBJECTIVE: Carotid-femoral pulse wave velocity (cfPWV) adds significantly to traditional cardiovascular (CV) risk prediction, but is not widely available. Therefore, it would be helpful if cfPWV could be replaced by an estimated carotid-femoral pulse wave velocity (ePWV) using age and mean blood...... pressure and previously published equations. The aim of this study was to investigate whether ePWV could predict CV events independently of traditional cardiovascular risk factors and/or cfPWV. DESIGN AND METHOD: cfPWV was measured and ePWV calculated in 2366 apparently healthy subjects from four age...

  17. Shock waves in water at low energy pulsed electric discharges

    International Nuclear Information System (INIS)

    Pinchuk, M E; Kolikov, V A; Rutberg, Ph G; Leks, A G; Dolinovskaya, R V; Snetov, V N; Stogov, A Yu

    2012-01-01

    Experimental results of shock wave formation and propagation in water at low energy pulsed electric discharges are presented. To study the hydrodynamic structure of the shock waves, the direct shadow optical diagnostic device with time resolution of 5 ns and spatial resolution of 0.1 mm was designed and developed. Synchronization of the diagnostic and electrodischarge units by the fast optocouplers was carried out. The dependences of shock wave velocities after breakdown of interelectrode gap for various energy inputs (at range of ≤1 J) into discharge were obtained. Based on the experimental results the recommendations for the adjustment parameters of the power supply and load were suggested.

  18. 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...

  19. Increasing vaccine production using pulsed ultrasound waves.

    Directory of Open Access Journals (Sweden)

    Jida Xing

    Full Text Available Vaccination is a safe and effective approach to prevent deadly diseases. To increase vaccine production, we propose that a mechanical stimulation can enhance protein production. In order to prove this hypothesis, Sf9 insect cells were used to evaluate the increase in the expression of a fusion protein from hepatitis B virus (HBV S1/S2. We discovered that the ultrasound stimulation at a frequency of 1.5 MHz, intensity of 60 mW/cm2, for a duration of 10 minutes per day increased HBV S1/S2 by 27%. We further derived a model for transport through a cell membrane under the effect of ultrasound waves, tested the key assumptions of the model through a molecular dynamics simulation package, NAMD (Nanoscale Molecular Dynamics program and utilized CHARMM force field in a steered molecular dynamics environment. The results show that ultrasound waves can increase cell permeability, which, in turn, can enhance nutrient / waste exchange thus leading to enhanced vaccine production. This finding is very meaningful in either shortening vaccine production time, or increasing the yield of proteins for use as vaccines.

  20. Wave fronts, pulses and wave trains in photoexcited superlattices behaving as excitable or oscillatory media

    International Nuclear Information System (INIS)

    Arana, J I; Bonilla, L L; Grahn, H T

    2011-01-01

    Undoped and strongly photoexcited semiconductor superlattices with field-dependent recombination behave as excitable or oscillatory media with spatially discrete nonlinear convection and diffusion. Infinitely long, dc-current-biased superlattices behaving as excitable media exhibit wave fronts with increasing or decreasing profiles, whose velocities can be calculated by means of asymptotic methods. These superlattices can also support pulses of the electric field. Pulses moving downstream with the flux of electrons can be constructed from their component wave fronts, whereas pulses advancing upstream do so slowly and experience saltatory motion: they change slowly in long intervals of time separated by fast transitions during which the pulses jump to the previous superlattice period. Photoexcited superlattices can also behave as oscillatory media and exhibit wave trains. (paper)

  1. Design of a bounded wave EMP (Electromagnetic Pulse) simulator

    Science.gov (United States)

    Sevat, P. A. A.

    1989-06-01

    Electromagnetic Pulse (EMP) simulators are used to simulate the EMP generated by a nuclear weapon and to harden equipment against the effects of EMP. At present, DREO has a 1 m EMP simulator for testing computer terminal size equipment. To develop the R and D capability for testing larger objects, such as a helicopter, a much bigger threat level facility is required. This report concerns the design of a bounded wave EMP simulator suitable for testing large size equipment. Different types of simulators are described and their pros and cons are discussed. A bounded wave parallel plate type simulator is chosen for it's efficiency and the least environmental impact. Detailed designs are given for 6 m and 10 m parallel plate type wire grid simulators. Electromagnetic fields inside and outside the simulators are computed. Preliminary specifications for a pulse generator required for the simulator are also given. Finally, the electromagnetic fields radiated from the simulator are computed and discussed.

  2. Experimental investigation of electron beam wave interactions utilising short pulses

    International Nuclear Information System (INIS)

    Wiggins, Samuel Mark

    2000-01-01

    Experiments have investigated the production of ultra-short electromagnetic pulses and their interaction with electrons in various resonant structures. Diagnostic systems used in the measurements included large bandwidth detection systems for capturing the short pulses. Deconvolution techniques have been applied to account for bandwidth limitation of the detection systems and to extract the actual pulse amplitudes and durations from the data. A Martin-Puplett interferometer has been constructed for use as a Fourier transform spectrometer. The growth of superradiant electromagnetic spikes from short duration (0.5-1.0 ns), high current (0.6-2.0 kA) electron pulses has been investigated in a Ka-band Cherenkov maser and Ka- and W-band backward wave oscillators (BWO). In the Cherenkov maser, radiation spikes were produced with a peak power ≤ 3 MW, a duration ≥ 70 ps and a bandwidth ≤ 19 %. It is shown that coherent spontaneous emission from the leading edge of the electron pulse drives these interactions, giving rise to self-amplified coherent spontaneous emission (SACSE). BWO spikes were produced with a peak power ≤ 63 MW and a pulse duration ∼ 250 ps in the Ka-band and ≤ 12 MW and ∼ 170 ps in the W-band. Evidence of superradiant evolution has been observed in the measurements of scaling laws such as power scaling with the current squared and duration scaling inversely with the fourth root of the power. An X-band free-electron maser amplifier, in which a short (1.0ns) injected radiation pulse interacts with a long (∼ 140 ns) electron beam, has been investigated. The interaction is shown to evolve in the linear regime. The peak output power was 320 kW, which corresponded to a gain, approximately constant across the band, of 42 dB. Changes to the spectrum, that occur when the input radiation pulse is injected into electrons with an energy gradient, have been analysed. (author)

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

    International Nuclear Information System (INIS)

    Yoon, Sunghyun; Cho, Young-Ho

    2014-01-01

    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 3.71cm 2 . 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. [Research on vigilance detection based on pulse wave].

    Science.gov (United States)

    Cao, Yong; Jiao, Xuejun; Pan, Jinjin; Jiang, Jin; Fu, Jiahao; Xu, Fenggang; Yang, Hanjun

    2017-12-01

    This paper studied the rule for the change of vigilance based on pulse wave. 10 participants were recruited in a 95-minute Mackworth clock test (MCT) experiment. During the experiment, the vigilance of all participants were evaluated by Karolinska sleepiness scale (KSS) and Stanford sleepiness scale (SSS), and behavior data (the reaction time and the accuracy of target) and pulse wave signal of the participants were recorded simultaneously. The result indicated that vigilance of the participants can be divided into 3 classes: the first 30 minutes for high vigilance level, the middle 30 minutes for general vigilance level, and the last 30 minutes for low vigilance level. Besides, time domain features such as amplitude of secondary peak, amplitude of peak and the latency of secondary peak decreased with the decrease of vigilance, while the amplitude of troughs increased. In terms of frequency domain features, the energy of 4 frequency band including 8.600 ~ 9.375 Hz, 11.720 ~ 12.500 Hz, 38.280 ~ 39.060 Hz and 39.060 ~ 39.840 Hz decreased with the decrease of vigilance. Finally, under the recognition model established by the 8 characteristics mentioned above, the average accuracy of three-classification results over the 10 participants was as high as 88.7%. The results of this study confirmed the feasibility of pulse wave in the evaluation of vigilance, and provided a new way for the real-time monitoring of vigilance.

  5. Laser-supported detonation waves and pulsed laser propulsion

    International Nuclear Information System (INIS)

    Kare, J.

    1990-01-01

    A laser thermal rocket uses the energy of a large remote laser, possibly ground-based, to heat an inert propellant and generate thrust. Use of a pulsed laser allows the design of extremely simple thrusters with very high performance compared to chemical rockets. The temperatures, pressures, and fluxes involved in such thrusters (10 4 K, 10 2 atmospheres, 10 7 w/cm 2 ) typically result in the creation of laser-supported detonation (LSD) waves. The thrust cycle thus involves a complex set of transient shock phenomena, including laser-surface interactions in the ignition of the LSD wave, laser-plasma interactions in the LSD wave itself, and high-temperature nonequilibrium chemistry behind the LSD wave. The SDIO Laser Propulsion Program is investigating these phenomena as part of an overall effort to develop the technology for a low-cost Earth-to-orbit laser launch system. We will summarize the Program's approach to developing a high performance thruster, the double-pulse planar thruster, and present an overview of some results obtained to date, along with a discussion of the many research question still outstanding in this area

  6. CALCULATION OF SHOCK-WAVE PULSE EFFECT ON OUTSTRETCHED SPINE

    Directory of Open Access Journals (Sweden)

    G. A. Esman

    2011-01-01

    Full Text Available Combined effects of a shock-wave pulse method and mechanotherapy on a spine is considered as an alternative to conservative and operative methods.Methodology for spinal disease treatment while applying a shock-wave therapy is characterized by the following specific features. Firstly, it is necessary to limit a penetration depth of shock pulses in a biological object in order to exclude damage to a spinal cord. Secondly, it is necessary to limit an energy flux density:Imax≤ 0,280 J∕m2and  pressure in focus:PFmax≤ 0,040 MPа,in order to exclude traumatizing of spinal tissue and only stimulate blood  circulation and metabolic processes in them.Where an acceptable value of the force acting on the inter-vertebral disc while a shock wave is passing is determined by the following formula: F max = PFmaxS = PFmax πr02 = 0,040 ∙106 ∙3,14 ∙(8∙10-32 = 9 N, where r0 – a focal spot radius, mm.Mechanotherapy is applied in combination with the shock-wave therapy and it presupposes the following: an outstretching force acts created in a longitudinal direction of the spine and it is directed across a vertebral column, whose value usually ranges from 50 to 500 N.   

  7. Shock wave interaction with pulsed glow discharge and afterglow plasmas

    International Nuclear Information System (INIS)

    Podder, N.K.; LoCascio, A.C.

    2009-01-01

    Acoustic shock waves are launched by the spark-discharge of a high voltage capacitor in pulsed glow discharge and afterglow plasmas. The glow discharge section of the shock tube is switched on for a period of less than one second at a time, during which a shock wave is launched starting with a large delay between the plasma switch-on and the shock-launch. In the subsequent runs this delay is decremented in equal time intervals up to the plasma switch-on time. A photo acoustic deflection method sensitive to the density gradient of the shock wave is used to study the propagating shock structure and velocity in the igniting plasma. A similar set of measurements are also performed at the plasma switch-off, in which the delay time is incremented in equal time intervals from the plasma switch-off time until the afterglow plasma fully neutralizes itself into the room-temperature gas. Thus, complete time histories of the shock wave propagation in the igniting plasma, as well as in the afterglow plasma, are produced. In the igniting plasma, the changes in the shock-front velocity and dispersion are found to be a strong non-linear function of delay until a saturation point is reached. On the other hand, in the afterglow plasma the trend has been opposite and reversing towards the room temperature values. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas

  8. Pulse energy evolution for high-resolution Lamb wave inspection

    International Nuclear Information System (INIS)

    Hua, Jiadong; Zeng, Liang; Gao, Fei; Lin, Jing

    2015-01-01

    Generally, tone burst excitation methods are used to reduce the effect of dispersion in Lamb wave inspection. In addition, algorithms for dispersion compensation are required to simplify responses, especially in long-range inspection. However, the resolution is always limited by the time duration of tone burst excitation. A pulse energy evolution method is established to overcome this limitation. In this method, a broadband signal with a long time (e.g. a chirp, white noise signal, or a pseudo-random sequence) is used as excitation to actuate Lamb waves. First of all, pulse compression is employed to estimate system impulse response with a high signal-to-noise ratio. Then, dispersion compensation is applied repeatedly with systemically varied compensation distances, obtaining a series of compensated signals. In these signals, amplitude (or energy) evolution associated with the change of compensation distance is utilized to estimate the actual propagation distance of the interested wave packet. Finally, the defect position is detected by an imaging algorithm. Several experiments are given to validate the proposed method. (paper)

  9. Optimization of arterial age prediction models based in pulse wave

    Energy Technology Data Exchange (ETDEWEB)

    Scandurra, A G [Bioengineering Laboratory, Electronic Department, Mar del Plata University (Argentina); Meschino, G J [Bioengineering Laboratory, Electronic Department, Mar del Plata University (Argentina); Passoni, L I [Bioengineering Laboratory, Electronic Department, Mar del Plata University (Argentina); Dai Pra, A L [Engineering Aplied Artificial Intelligence Group, Mathematics Department, Mar del Plata University (Argentina); Introzzi, A R [Bioengineering Laboratory, Electronic Department, Mar del Plata University (Argentina); Clara, F M [Bioengineering Laboratory, Electronic Department, Mar del Plata University (Argentina)

    2007-11-15

    We propose the detection of early arterial ageing through a prediction model of arterial age based in the coherence assumption between the pulse wave morphology and the patient's chronological age. Whereas we evaluate several methods, a Sugeno fuzzy inference system is selected. Models optimization is approached using hybrid methods: parameter adaptation with Artificial Neural Networks and Genetic Algorithms. Features selection was performed according with their projection on main factors of the Principal Components Analysis. The model performance was tested using the bootstrap error type .632E. The model presented an error smaller than 8.5%. This result encourages including this process as a diagnosis module into the device for pulse analysis that has been developed by the Bioengineering Laboratory staff.

  10. Optimization of arterial age prediction models based in pulse wave

    International Nuclear Information System (INIS)

    Scandurra, A G; Meschino, G J; Passoni, L I; Dai Pra, A L; Introzzi, A R; Clara, F M

    2007-01-01

    We propose the detection of early arterial ageing through a prediction model of arterial age based in the coherence assumption between the pulse wave morphology and the patient's chronological age. Whereas we evaluate several methods, a Sugeno fuzzy inference system is selected. Models optimization is approached using hybrid methods: parameter adaptation with Artificial Neural Networks and Genetic Algorithms. Features selection was performed according with their projection on main factors of the Principal Components Analysis. The model performance was tested using the bootstrap error type .632E. The model presented an error smaller than 8.5%. This result encourages including this process as a diagnosis module into the device for pulse analysis that has been developed by the Bioengineering Laboratory staff

  11. Wavelet brain angiography suggests arteriovenous pulse wave phase locking.

    Directory of Open Access Journals (Sweden)

    William E Butler

    Full Text Available When a stroke volume of arterial blood arrives to the brain, the total blood volume in the bony cranium must remain constant as the proportions of arterial and venous blood vary, and by the end of the cardiac cycle an equivalent volume of venous blood must have been ejected. I hypothesize the brain to support this process by an extraluminally mediated exchange of information between its arterial and venous circulations. To test this I introduce wavelet angiography methods to resolve single moving vascular pulse waves (PWs in the brain while simultaneously measuring brain pulse motion. The wavelet methods require angiographic data acquired at significantly faster rate than cardiac frequency. I obtained these data in humans from brain surface optical angiograms at craniotomy and in piglets from ultrasound angiograms via cranial window. I exploit angiographic time of flight to resolve arterial from venous circulation. Initial wavelet reconstruction proved unsatisfactory because of angiographic motion alias from brain pulse motion. Testing with numerically simulated cerebral angiograms enabled the development of a vascular PW cine imaging method based on cross-correlated wavelets of mixed high frequency and high temporal resolution respectively to attenuate frequency and motion alias. Applied to the human and piglet data, the method resolves individual arterial and venous PWs and finds them to be phase locked each with separate phase relations to brain pulse motion. This is consistent with arterial and venous PW coordination mediated by pulse motion and points to a testable hypothesis of a function of cerebrospinal fluid in the ventricles of the brain.

  12. Uric Acid Level Has a J-Shaped Association with Arterial Stiffness in Korean Postmenopausal Women.

    Science.gov (United States)

    Lee, Hyungbin; Jung, Young-Hyo; Kwon, Yu-Jin; Park, Byoungjin

    2017-11-01

    Uric acid has been reported to function both as an oxidant or antioxidant depending on the context. A previous study in the Korean population reported a positive linear association between serum uric acid level and arterial stiffness in men, but little is known about how serum uric acid level is related to the risk of increased arterial stiffness in Korean postmenopausal women. We performed a cross-sectional study of 293 subjects who participated in a health examination program run by the health promotion center of Gangnam Severance Hospital between October 2007 and July 2010. High brachial-ankle pulse wave velocity was defined as a brachial-ankle pulse wave velocity of more than 1,450 cm/s. The odds ratios (ORs) for high brachial-ankle pulse wave velocity were calculated using multivariate logistic regression analysis across uric acid quartiles after adjusting for other indicators of cardiovascular risk. The 293 postmenopausal women were divided into quartiles according to uric acid level. The mean brachial-ankle pulse wave velocity values of each quartile were as follows: Q1, 1,474 cm/s; Q2, 1,375 cm/s; Q3, 1,422 cm/s; Q4, 1,528 cm/s. The second quartile was designated as the control group based on mean brachial-ankle pulse wave velocity value. Multivariate adjusted ORs (95% confidence intervals) for brachial-ankle pulse wave velocity across the uric acid quartiles were 2.642 (Q1, 1.095-6.3373), 1.00, 4.305 (Q3, 1.798-10.307), and 4.375 (Q4, 1.923-9.949), after adjusting for confounding variables. Serum uric acid level has a J-shaped association with arterial stiffness in Korean postmenopausal women.

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

    International Nuclear Information System (INIS)

    Yuan Guoyong; Yang Shiping; Wang Guangrui; Chen Shigang

    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 (t 0 ). 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

  14. Pulse wave velocity and cognitive function in older adults.

    Science.gov (United States)

    Zhong, Wenjun; Cruickshanks, Karen J; Schubert, Carla R; Carlsson, Cynthia M; Chappell, Richard J; Klein, Barbara E K; Klein, Ronald; Acher, Charles W

    2014-01-01

    Arterial stiffness may be associated with cognitive function. In this study, pulse wave velocity (PWV) was measured from the carotid to femoral (CF-PWV) and from the carotid to radial (CR-PWV) with the Complior SP System. Cognitive function was measured by 6 tests of executive function, psychomotor speed, memory, and language fluency. A total of 1433 participants were included (mean age 75 y, 43% men). Adjusting for age, sex, education, pulse rate, hemoglobin A1C, high-density lipoprotein cholesterol, hypertension, cardiovascular disease history, smoking, drinking, and depression symptoms, a CF-PWV>12 m/s was associated with a lower Mini-Mental State Examination score (coefficient: -0.31, SE: 0.11, P=0.005), fewer words recalled on Auditory Verbal Learning Test (coefficient: -1.10, SE: 0.43, P=0.01), and lower score on the composite cognition score (coefficient: -0.10, SE: 0.05, P=0.04) and marginally significantly associated with longer time to complete Trail Making Test-part B (coefficient: 6.30, SE: 3.41, P=0.06), CF-PWV was not associated with Trail Making Test-part A, Digit Symbol Substation Test, or Verbal Fluency Test. No associations were found between CR-PWV and cognitive performance measures. Higher large artery stiffness was associated with worse cognitive function, and longitudinal studies are needed to confirm these associations.

  15. Heat wave propagation in a thin film irradiated by ultra-short laser pulses

    International Nuclear Information System (INIS)

    Yoo, Jae Gwon; Kim, Cheol Jung; Lim, C. H.

    2004-01-01

    A thermal wave solution of a hyperbolic heat conduction equation in a thin film is developed on the basis of the Green's function formalism. Numerical computations are carried out to investigate the temperature response and the propagation of the thermal wave inside a thin film due to a heat pulse generated by ultra-short laser pulses with various laser pulse durations and thickness of the film

  16. 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.

  17. 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.

  18. [De-noising and measurement of pulse wave velocity of the wavelet].

    Science.gov (United States)

    Liu, Baohua; Zhu, Honglian; Ren, Xiaohua

    2011-02-01

    Pulse wave velocity (PWV) is a vital index of the cardiovascular pathology, so that the accurate measurement of PWV can be of benefit for prevention and treatment of cardiovascular diseases. The noise in the measure system of pulse wave signal, rounding error and selection of the recording site all cause errors in the measure result. In this paper, with wavelet transformation to eliminate the noise and to raise the precision, and with the choice of the point whose slope was maximum as the recording site of the reconstructing pulse wave, the measuring system accuracy was improved.

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

    Science.gov (United States)

    Wu, Hau-Tieng; Wu, Han-Kuei; 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.

  20. 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.

  1. Simulation study on cross polarization scattering of ultrashort-pulse electromagnetic waves

    International Nuclear Information System (INIS)

    Katsuragawa, Naoki; Hojo, Hitoshi; Mase, Atushi

    1996-11-01

    Simulation study on cross polarization scattering of ultrashort-pulse electromagnetic waves due to magnetic fluctuations is presented. One-dimensional coupled wave equations for the ordinary and extraordinary modes are solved for incident unipolar sub-cycle pulses in an inhomogeneous magnetized plasma. It is shown that the peak frequencies in the frequency-spectral signals of the mode-converted reflected waves are determined from the Bragg resonance condition in the wave numbers of the ordinary mode, the extraordinary mode and the magnetic fluctuations for relatively short-wavelength localized magnetic fluctuations. (author)

  2. Excitation of plasma waves by nonlinear currents induced by a high-frequency electromagnetic pulse

    Energy Technology Data Exchange (ETDEWEB)

    Grishkov, V. E.; Uryupin, S. A., E-mail: uryupin@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2017-03-15

    Excitation of plasma waves by nonlinear currents induced by a high-frequency electromagnetic pulse is analyzed within the kinetic approach. It is shown that the most efficient source of plasma waves is the nonlinear current arising due to the gradient of the energy density of the high-frequency field. Generation of plasma waves by the drag current is usually less efficient but not negligibly small at relatively high frequencies of electron–ion collisions. The influence of electron collisions on the excitation of plasma waves by pulses of different duration is described quantitatively.

  3. Theory of spin and lattice wave dynamics excited by focused laser pulses

    Science.gov (United States)

    Shen, Ka; Bauer, Gerrit E. W.

    2018-06-01

    We develop a theory of spin wave dynamics excited by ultrafast focused laser pulses in a magnetic film. We take into account both the volume and surface spin wave modes in the presence of applied, dipolar and magnetic anisotropy fields and include the dependence on laser spot exposure size and magnetic damping. We show that the sound waves generated by local heating by an ultrafast focused laser pulse can excite a wide spectrum of spin waves (on top of a dominant magnon–phonon contribution). Good agreement with recent experiments supports the validity of the model.

  4. Daily dialysis reduces pulse wave velocity in chronic hemodialysis patients.

    Science.gov (United States)

    Di Micco, Lucia; Torraca, Serena; Sirico, Maria Luisa; Tartaglia, Domenico; Di Iorio, Biagio

    2012-05-01

    Pulse wave velocity (PWV) is a predictor of morbidity and mortality in patients with end-stage renal disease (ESRD). Dialysis patients show cyclic changes in PWV related to their hydration status and blood pressure. Our aim is to assess the impact of daily dialysis on PWV. We performed a randomized crossover study of 60 patients who underwent standard hemodialysis (HD) three times per week for at least 6 months. Patients were classified into three groups according to their PWV values before (pre-) and after (post-) HD, with a cutoff value of 12 m s(-1), as follows: the low-low (LL) group had normal pre-HD and post-HD PWV; the high-low (HL) group had high pre-HD PWV and normal post-HD PWV; and the high-high (HH) group had high pre- and post-HD PWV. All patients continued standard HD for 2 weeks. A total of 10 patients from each group were randomly assigned to continue standard HD for 1 week and then underwent daily dialysis for 1 week. The remaining 10 patients underwent daily dialysis for 1 week and then underwent standard HD for 1 week. PWV values were measured before and 1 h after each dialysis session. With daily dialysis treatment, 2 of 20 patients (10%) moved from the PWV-HH group to the PWV-HL group, whereas 18 of 20 patients (90%) moved from the PWV-HL group to the PWV-LL group (P = 0.030). Daily dialysis reduces PWV in the ESRD patients. As PWV is a strong predictor of mortality in ESRD and has cyclic variations in patients who are on standard HD, we believe that daily dialysis may be used in patients with high PWV levels to reduce their mortality risk.

  5. Wake-Field Wave Resonant Excitation in Magnetized Plasmas by Electromagnetic Pulse

    International Nuclear Information System (INIS)

    Milant'ev, V.P.; Turikov, V.A.

    2006-01-01

    In this paper the space charge wave excitation process at electromagnetic pulse propagation along external magnetic field in vicinity of electron cyclotron resonance. In hydrodynamic approach it is obtained an equation for plasma density under ponderomotive force action. With help of this equation we investigated a wake-field wave amplitude dependence from resonance detuning. The numerical simulation using a PIC method electromagnetic pulse propagation process in the resonant conditions was done

  6. 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....

  7. Oscillatory pulses and wave trains in a bistable reaction-diffusion system with cross diffusion.

    Science.gov (United States)

    Zemskov, Evgeny P; Tsyganov, Mikhail A; Horsthemke, Werner

    2017-01-01

    We study waves with exponentially decaying oscillatory tails in a reaction-diffusion system with linear cross diffusion. To be specific, we consider a piecewise linear approximation of the FitzHugh-Nagumo model, also known as the Bonhoeffer-van der Pol model. We focus on two types of traveling waves, namely solitary pulses that correspond to a homoclinic solution, and sequences of pulses or wave trains, i.e., a periodic solution. The effect of cross diffusion on wave profiles and speed of propagation is analyzed. We find the intriguing result that both pulses and wave trains occur in the bistable cross-diffusive FitzHugh-Nagumo system, whereas only fronts exist in the standard bistable system without cross diffusion.

  8. Development of integrated photoplethysmographic recording circuit for trans-nail pulse-wave monitoring system

    Science.gov (United States)

    Qian, Zhengyang; Takezawa, Yoshiki; Shimokawa, Kenji; Kino, Hisashi; Fukushima, Takafumi; Kiyoyama, Koji; Tanaka, Tetsu

    2018-04-01

    Health monitoring and self-management have become increasingly more important because of health awareness improvement, the aging of population, and other reasons. In general, pulse waves are among the most useful physiological signals that can be used to calculate several parameters such as heart rate and blood pressure for health monitoring and self-management. To realize an automatic and real-time pulse-wave monitoring system that can be used in daily life, we have proposed a trans-nail pulse-wave monitoring system that was placed on the fingernail to detect photoplethysmographic (PPG) signals as pulse waves. In this study, we designed a PPG recording circuit that was composed of a 600 × 600 µm2 photodiode (PD), an LED driver with pulse wave modulation (PWM) and a low-frequency ring oscillator (RING), and a PPG signal readout circuit. The proposed circuit had a very small area of 2.2 × 1.1 mm2 designed with 0.18 µm CMOS technology. The proposed circuit was used to detect pulse waves on the human fingernail in both the reflection and transmission modes. Electrical characteristics of the prototype system were evaluated precisely and PPG waveforms were obtained successfully.

  9. 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...

  10. Increasing accuracy of pulse transit time measurements by automated elimination of distorted photoplethysmography waves

    NARCIS (Netherlands)

    M.H.N. van Velzen (M. H N); A.J. Loeve (Arjo J.); S.P. Niehof (Sjoerd); E.G. Mik (Egbert)

    2017-01-01

    textabstractPhotoplethysmography (PPG) is a widely available non-invasive optical technique to visualize pressure pulse waves (PWs). Pulse transit time (PTT) is a physiological parameter that is often derived from calculations on ECG and PPG signals and is based on tightly defined characteristics of

  11. Increasing accuracy of pulse transit time measurements by automated elimination of distorted photoplethysmography waves

    NARCIS (Netherlands)

    van Velzen, M.H.N.; Loeve, A.J.; Niehof, S.P.; Mik, E.G.

    2017-01-01

    Photoplethysmography (PPG) is a widely available non-invasive optical technique to visualize pressure pulse waves (PWs). Pulse transit time (PTT) is a physiological parameter that is often derived from calculations on ECG and PPG signals and is based on tightly defined characteristics of the PW

  12. 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.

  13. Pulsed discharges produced by high-power surface waves

    Science.gov (United States)

    Böhle, A.; Ivanov, O.; Kolisko, A.; Kortshagen, U.; Schlüter, H.; Vikharev, A.

    1996-02-01

    The mechanisms of the ionization front advance in surface-wave-produced discharges are investigated using two experimental set-ups. The high-power surface waves are excited in a 3 cm wavelength band by a surfaguide and a novel type of launcher (an E-plane junction). The ionization front velocity of the surface wave is measured for a wide range of gas pressures, incident microwave power and initial pre-ionization. The experimental results are compared with theoretical ones based on three different models. The comparison between theory and experiment allows one to suggest a new interpretation of the ionization front's advance. The ionization front velocity is determined by a breakdown wave or an ionization wave in the electric field of a high-power surface wave in the zone near the ionization front.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    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 r 2 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 2 in the AAA subjects was significantly lower (p 2 ) obtained using PWI, in addition to the PWI images and spatio-temporal maps that provide qualitative visualization of the pulse wave, may potentially provide valuable information for the clinical characterization of aneurysms and other vascular pathologies that regionally alter the arterial wall mechanics. (paper)

  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....... In particular, the signal-to-background ratio can be optimized for a specific amplifier gain. This behavior, which is coherently described in experiment and theory, is attributed to the dynamics of the amplified spontaneous emission, which is the main source of noise in a semiconductor optical amplifier....

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

    International Nuclear Information System (INIS)

    Petrishchev, Vitaly; Leonov, Sergey; Adamovich, Igor V

    2014-01-01

    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

  17. Speed of Wave Pulses in Hooke's Law Media

    Science.gov (United States)

    Huggins, Elisha

    2008-01-01

    As students watched a compressional pulse bounce back and forth on the horizontally suspended Slinky[TM], shown in Fig. 1, we wrote down the formula for the speed of the pulse and promised that later in the course we would derive the formula. The problem is we did not keep our promise in the course. Here is where we are keeping the promise. As…

  18. FPGA-based design and implementation of arterial pulse wave generator using piecewise Gaussian-cosine fitting.

    Science.gov (United States)

    Wang, Lu; Xu, Lisheng; Zhao, Dazhe; Yao, Yang; Song, Dan

    2015-04-01

    Because arterial pulse waves contain vital information related to the condition of the cardiovascular system, considerable attention has been devoted to the study of pulse waves in recent years. Accurate acquisition is essential to investigate arterial pulse waves. However, at the stage of developing equipment for acquiring and analyzing arterial pulse waves, specific pulse signals may be unavailable for debugging and evaluating the system under development. To produce test signals that reflect specific physiological conditions, in this paper, an arterial pulse wave generator has been designed and implemented using a field programmable gate array (FPGA), which can produce the desired pulse waves according to the feature points set by users. To reconstruct a periodic pulse wave from the given feature points, a method known as piecewise Gaussian-cosine fitting is also proposed in this paper. Using a test database that contains four types of typical pulse waves with each type containing 25 pulse wave signals, the maximum residual error of each sampling point of the fitted pulse wave in comparison with the real pulse wave is within 8%. In addition, the function for adding baseline drift and three types of noises is integrated into the developed system because the baseline occasionally wanders, and noise needs to be added for testing the performance of the designed circuits and the analysis algorithms. The proposed arterial pulse wave generator can be considered as a special signal generator with a simple structure, low cost and compact size, which can also provide flexible solutions for many other related research purposes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Relativistic solitary waves modulating long laser pulses in plasmas

    International Nuclear Information System (INIS)

    Sanchez-Arriaga, G; Siminos, E; Lefebvre, E

    2011-01-01

    This paper 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 a mathematical point of view they are exact solutions of the one-dimensional relativistic cold fluid plasma model with nonvanishing boundary conditions. Under the assumption of travelling wave solutions with velocity V and vector potential frequency ω, the fluid model is reduced to a Hamiltonian system. The solitary waves are homoclinic (grey solitons) or heteroclinic (dark solitons) orbits to fixed points. Using a dynamical systems description of the Hamiltonian system and a spectral method, we identify a large 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 solutions come in continuous families in the parametric V-ω plane and extend up to velocities that approach the speed of light. The stability of certain types of grey solitary waves is investigated with the aid of particle-in-cell simulations that demonstrate their propagation for a few tens of the inverse of the plasma frequency.

  20. Visible continuum pulses based on enhanced dispersive wave generation for endogenous fluorescence imaging.

    Science.gov (United States)

    Cui, Quan; Chen, Zhongyun; Liu, Qian; Zhang, Zhihong; Luo, Qingming; Fu, Ling

    2017-09-01

    In this study, we demonstrate endogenous fluorescence imaging using visible continuum pulses based on 100-fs Ti:sapphire oscillator and a nonlinear photonic crystal fiber. Broadband (500-700 nm) and high-power (150 mW) continuum pulses are generated through enhanced dispersive wave generation by pumping femtosecond pulses at the anomalous dispersion region near zero-dispersion wavelength of high-nonlinear photonic crystal fibers. We also minimize the continuum pulse width by determining the proper fiber length. The visible-wavelength two-photon microscopy produces NADH and tryptophan images of mice tissues simultaneously. Our 500-700 nm continuum pulses support extending nonlinear microscopy to visible wavelength range that is inaccessible to 100-fs Ti:sapphire oscillators and other applications requiring visible laser pulses.

  1. Ionization waves in the pre-breakdown phase of a pulsed capillary discharge

    International Nuclear Information System (INIS)

    Favre, M.; Lenero, A.M.; Chuaqui, H.; Mitchell, I.; Wyndham, E.; Choi, P.; Dumitrescu, C.; Mond, M.; Rutkevich, I.; Kaufman, Y.

    2001-01-01

    We present experimental observations of ionization waves in pulsed hollow cathode capillary discharges. When the capillary shield is at the anode potential, an anode directed ionization wave, with characteristic speed ∼10 7 m/s, is observed. When the capillary shield is at the cathode potential, a cathode directed slower ionization wave, with characteristic speed ∼10 4 m/s, is observed. The several orders of magnitude difference in the ionization wave speed can be attributed to the different initial electric field configuration in both polarities

  2. Steering dissociation of Br2 molecules with two femtosecond pulses via wave packet interference.

    Science.gov (United States)

    Han, Yong-Chang; Yuan, Kai-Jun; Hu, Wen-Hui; Yan, Tian-Min; Cong, Shu-Lin

    2008-04-07

    The dissociation dynamics of Br2 molecules induced by two femtosecond pump pulses are studied based on the calculation of time-dependent quantum wave packet. Perpendicular transition from X 1Sigma g+ to A 3Pi 1u+ and 1Pi 1u+ and parallel transition from X 1Sigma g+ to B 3Pi 0u+, involving two product channels Br (2P3/2)+Br (2P3/2) and Br (2P3/2)+Br* (2P1/2), respectively, are taken into account. Two pump pulses create dissociating wave packets interfering with each other. By varying laser parameters, the interference of dissociating wave packets can be controlled, and the dissociation probabilities of Br2 molecules on the three excited states can be changed to different degrees. The branching ratio of Br*/(Br+Br*) is calculated as a function of pulse delay time and phase difference.

  3. A differential optical interferometer for measuring short pulses of surface acoustic waves.

    Science.gov (United States)

    Shaw, Anurupa; Teyssieux, Damien; Laude, Vincent

    2017-09-01

    The measurement of the displacements caused by the propagation of a short pulse of surface acoustic waves on a solid substrate is investigated. A stabilized time-domain differential interferometer is proposed, with the surface acoustic wave (SAW) sample placed outside the interferometer. Experiments are conducted with surface acoustic waves excited by a chirped interdigital transducer on a piezoelectric lithium niobate substrate having an operational bandwidth covering the 200-400MHz frequency range and producing 10-ns pulses with 36nm maximum out-of-plane displacement. The interferometric response is compared with a direct electrical measurement obtained with a receiving wide bandwidth interdigital transducer and good correspondence is observed. The effects of varying the path difference of the interferometer and the measurement position on the surface are discussed. Pulse compression along the chirped interdigital transducer is observed experimentally. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Shock wave generation in laser ablation studied using pulsed digital holographic interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Amer, Eynas; Gren, Per; Sjoedahl, Mikael [Division of Experimental Mechanics, Luleaa University of Technology, SE-971 87 Luleaa (Sweden)], E-mail: eynas.amer@ltu.se, E-mail: per.gren@ltu.se, E-mail: mikael.sjodahl@ltu.se

    2008-11-07

    Pulsed digital holographic interferometry has been used to study the shock wave induced by a Q-switched Nd-YAG laser ({lambda} = 1064 nm and pulse duration 12 ns) on a polycrystalline boron nitride (PCBN) ceramic target under atmospheric air pressure. A special setup based on using two synchronized wavelengths from the same laser for processing and measurement simultaneously has been introduced. Collimated laser light ({lambda} = 532 nm) passed through the volume along the target and digital holograms were recorded for different time delays after processing starts. Numerical data of the integrated refractive index field were calculated and presented as phase maps showing the propagation of the shock wave generated by the process. The location of the induced shock wave front was observed for different focusing and time delays. The amount of released energy, i.e. the part of the incident energy of the laser pulse that is eventually converted to a shock wave has been estimated using the point explosion model. The released energy is normalized by the incident laser pulse energy and the energy conversion efficiency between the laser pulse and PCBN target has been calculated at different power densities. The results show that the energy conversion efficiency seems to be constant around 80% at high power densities.

  5. Two-wave generator of subnanosecond radiation pulses on an yttrium-aluminium garnet

    International Nuclear Information System (INIS)

    Babikov, Yu.I.; Ir, K.S.; Mironov, V.E.

    1988-01-01

    Great attention is paid to the electron accelerator based on the mechanism of electron accelerator in the field of plasma wave, excited by laser radiation. The laser system master generator based on serial LTIPC-8 laser is described. The system is intended for investigating the plasma excitation processes initiated by two-frequency laser radiation beats. Pulse duration is ≤1 ns at 3-4 pulse train. Radiation on 1.0615 and 1.0641 μm wave length is generated. 5 refs.; 3 figs

  6. Design of a Continuous Blood Pressure Measurement System Based on Pulse Wave and ECG Signals.

    Science.gov (United States)

    Li, Jian-Qiang; Li, Rui; Chen, Zhuang-Zhuang; Deng, Gen-Qiang; Wang, Huihui; Mavromoustakis, Constandinos X; Song, Houbing; Ming, Zhong

    2018-01-01

    With increasingly fierce competition for jobs, the pressures on people have risen in recent years, leading to lifestyle and diet disorders that result in significantly higher risks of cardiovascular disease. Hypertension is one of the common chronic cardiovascular diseases; however, mainstream blood pressure measurement devices are relatively heavy. When multiple measurements are required, the user experience and the measurement results may be unsatisfactory. In this paper, we describe the design of a signal collection module that collects pulse waves and electrocardiograph (ECG) signals. The collected signals are input into a signal processing module to filter the noise and amplify the useful physiological signals. Then, we use a wavelet transform to eliminate baseline drift noise and detect the feature points of the pulse waves and ECG signals. We propose the concept of detecting the wave shape associated with an instance, an approach that minimizes the impact of atypical pulse waves on blood pressure measurements. Finally, we propose an improved method for measuring blood pressure based on pulse wave velocity that improves the accuracy of blood pressure measurements by 58%. Moreover, the results meet the american medical instrument promotion association standards, which demonstrate the feasibility of our measurement system.

  7. The velocity of the arterial pulse wave: a viscous-fluid shock wave in an elastic tube.

    Science.gov (United States)

    Painter, Page R

    2008-07-29

    The arterial pulse is a viscous-fluid shock wave that is initiated by blood ejected from the heart. This wave travels away from the heart at a speed termed the pulse wave velocity (PWV). The PWV increases during the course of a number of diseases, and this increase is often attributed to arterial stiffness. As the pulse wave approaches a point in an artery, the pressure rises as does the pressure gradient. This pressure gradient increases the rate of blood flow ahead of the wave. The rate of blood flow ahead of the wave decreases with distance because the pressure gradient also decreases with distance ahead of the wave. Consequently, the amount of blood per unit length in a segment of an artery increases ahead of the wave, and this increase stretches the wall of the artery. As a result, the tension in the wall increases, and this results in an increase in the pressure of blood in the artery. An expression for the PWV is derived from an equation describing the flow-pressure coupling (FPC) for a pulse wave in an incompressible, viscous fluid in an elastic tube. The initial increase in force of the fluid in the tube is described by an increasing exponential function of time. The relationship between force gradient and fluid flow is approximated by an expression known to hold for a rigid tube. For large arteries, the PWV derived by this method agrees with the Korteweg-Moens equation for the PWV in a non-viscous fluid. For small arteries, the PWV is approximately proportional to the Korteweg-Moens velocity divided by the radius of the artery. The PWV in small arteries is also predicted to increase when the specific rate of increase in pressure as a function of time decreases. This rate decreases with increasing myocardial ischemia, suggesting an explanation for the observation that an increase in the PWV is a predictor of future myocardial infarction. The derivation of the equation for the PWV that has been used for more than fifty years is analyzed and shown to yield

  8. A pulsed electron gun for the Plane Wave Transformer Linac

    Science.gov (United States)

    Mahadevan, S.; Gandhi, M. L.; Nandedkar, R. V.

    2003-01-01

    A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 μperv and the normalized emittance is within 5 π mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance.

  9. A pulsed electron gun for the Plane Wave Transformer Linac

    Energy Technology Data Exchange (ETDEWEB)

    Mahadevan, S. E-mail: maharaja@cat.ernet.in; Gandhi, M.L. E-mail: mlg@cat.ernet.in; Nandedkar, R.V. E-mail: nrv@cat.ernet.in

    2003-01-01

    A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 {mu}perv and the normalized emittance is within 5{pi} mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance.

  10. A pulsed electron gun for the Plane Wave Transformer Linac

    CERN Document Server

    Mahadevan, S; Nandedkar, R V

    2003-01-01

    A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 mu perv and the normalized emittance is within 5 pi mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance.

  11. A pulsed electron gun for the Plane Wave Transformer Linac

    International Nuclear Information System (INIS)

    Mahadevan, S.; Gandhi, M.L.; Nandedkar, R.V.

    2003-01-01

    A pulsed diode electron gun delivering 500 mA current at 40 kV is described. The gun geometry is optimized using the Electron Trajectory Program EGUN at higher scaling factors by choosing the closest converging starting surface. The effect of an annular gap between cathode and focusing electrode on beam behaviour is compensated by using a suitable focusing electrode. The estimated perveance is 0.065 μperv and the normalized emittance is within 5π mm mrad. The variation in current density at the cathode has been limited to within 10% across the face of the cathode. Salient features of the pulsed power supply and an insight of its interconnection with the gun are presented. The current measured at the Faraday cup is in agreement with the designed perveance

  12. Upconversion imaging using short-wave infrared picosecond pulses

    DEFF Research Database (Denmark)

    Mathez, Morgan David; Rodrigo, Peter John; Tidemand-Lichtenberg, Peter

    2017-01-01

    beam diameter to upconvert a wider range of signal spatial frequencies in the crystal. The 1877 nm signal is converted into 849 nm—enabling an image to be acquired by a silicon CCD camera. The measured size of the smallest resolvable element of this imaging system is consistent with the value predicted...... repetition rate of 21.7 MHz. Due to synchronization of high peak-power pulses, efficient upconversion is achieved in a single-pass setup that employs a bulk lithium niobate crystal. Optimizing the temporal overlap of the pulses for high upconversion efficiency enables us to exploit a relatively large pump...... by an improved model that considers the combined image blurring effect due to finite pump beam size, thick nonlinear crystal, and polychromatic infrared illumination....

  13. Liberation of a pinned spiral wave by a rotating electric pulse

    Science.gov (United States)

    Chen, Jiang-Xing; Peng, Liang; Ma, Jun; Ying, He-Ping

    2014-08-01

    Spiral waves may be pinned to anatomical heterogeneities in the cardiac tissue, which leads to monomorphic ventricular tachycardia. Wave emission from heterogeneities (WEH) induced by electric pulses in one direction (EP) is a promising method for liberating such waves by using heterogeneities as internal virtual pacing sites. Here, based on the WEH effect, a new mechanism of liberation by means of a rotating electric pulse (REP) is proposed in a generic model of excitable media. Compared with the EP, the REP has the advantage of opening wider time window to liberate pinned spiral. The influences of rotating direction and frequency of the REP, and the radius of the obstacles on this new mechanism are studied. We believe this strategy may improve manipulations with pinned spiral waves in heart experiments.

  14. Attosecond ionization gating for isolated attosecond electron wave packet and broadband attosecond xuv pulses

    International Nuclear Information System (INIS)

    Lan Pengfei; Lu Peixiang; Cao Wei; Li Yuhua; Wang Xinlin

    2007-01-01

    An attosecond ionization gating is achieved using a few-cycle laser pulse in combination with its second harmonic. With this gating, the generation of the electron wave packet (EWP) is coherently controlled, and an isolated EWP of about 270 as is generated. An isolated broadband attosecond extreme ultraviolet pulse with a bandwidth of about 75 eV can also be generated using this gating, which can be used for EWP measurements as efficiently as a 50-as pulse, allowing one to measure a wide range of ultrafast dynamics not normally accessible before

  15. Pulse picker for synchrotron radiation driven by a surface acoustic wave.

    Science.gov (United States)

    Vadilonga, Simone; Zizak, Ivo; Roshchupkin, Dmitry; Petsiuk, Andrei; Dolbnya, Igor; Sawhney, Kawal; Erko, Alexei

    2017-05-15

    A functional test for a pulse picker for synchrotron radiation was performed at Diamond Light Source. The purpose of a pulse picker is to select which pulse from the synchrotron hybrid-mode bunch pattern reaches the experiment. In the present work, the Bragg reflection on a Si/B4C multilayer was modified using surface acoustic wave (SAW) trains. Diffraction on the SAW alters the direction of the x rays and it can be used to modulate the intensity of the x rays that reach the experimental chamber. Using electronic modulation of the SAW amplitude, it is possible to obtain different scattering conditions for different x-ray pulses. To isolate the single bunch, the state of the SAW must be changed in the short time gap between the pulses. To achieve the necessary time resolution, the measurements have been performed in conical diffraction geometry. The achieved time resolution was 120 ns.

  16. Measurement of Aortic Pulse Wave Velocity With a Connected Bathroom Scale.

    Science.gov (United States)

    Campo, David; Khettab, Hakim; Yu, Roger; Genain, Nicolas; Edouard, Paul; Buard, Nadine; Boutouyrie, Pierre

    2017-09-01

    Measurement of arterial stiffness should be more available. Our aim was to show that aortic pulse wave velocity can be reliably measured with a bathroom scale combining the principles of ballistocardiography (BCG) and impedance plethysmography on a single foot. The calibration of the bathroom scale was conducted on a group of 106 individuals. The aortic pulse wave velocity was measured with the SphygmoCor in the supine position. Three consecutive measurements were then performed on the Withings scale in the standing position. This aorta-leg pulse transit time (alPTT) was then converted into a velocity with the additional input of the height of the person. Agreement between the SphygmoCor and the bathroom scale so calibrated is assessed on a separate group of 86 individuals, following the same protocol. The bias is 0.25 m·s-1 and the SE 1.39 m·s-1. This agreement with Sphygmocor is "acceptable" according to the ARTERY classification. The alPTT correlated well with cfPTT with (Spearman) R = 0.73 in pooled population (cal 0.79, val 0.66). The aorta-leg pulse wave velocity correlated with carotid-femoral pulse wave velocity with R = 0.76 (cal 0.80, val 0.70). Estimation of the aortic pulse wave velocity is feasible with a bathroom scale. Further investigations are needed to improve the repeatability of measurements and to test their accuracy in different populations and conditions. © The Author 2017. Published by Oxford University Press on behalf of American Journal of Hypertension.

  17. Evanescent-wave proton postaccelerator driven by intense THz pulse

    OpenAIRE

    L. Pálfalvi; J. A. Fülöp; Gy. Tóth; J. Hebling

    2014-01-01

    Hadron therapy motivates research dealing with the production of particle beams with ∼100  MeV/nucleon energy and relative energy fluctuation on the order of 1%. Laser-driven accelerators produce ion beams with only tens of MeV/nucleon energy and an extremely broad spectra. Here, a novel method is proposed for postacceleration and monochromatization of particles, leaving the laser-driven accelerator, by using intense THz pulses. It is based on further developing the idea of using the evanesce...

  18. Supersonic Ionization Wave Driven by Radiation Transport in a Short-Pulse Laser-Produced Plasma

    International Nuclear Information System (INIS)

    Ditmire, T.; Gumbrell, E.T.; Smith, R.A.; Mountford, L.; Hutchinson, M.H.

    1996-01-01

    Through the use of an ultrashort (2ps) optical probe, we have time resolved the propagation of an ionization wave into solid fused silica. This ionization wave results when a plasma is created by the intense irradiation of a solid target with a 2ps laser pulse. We find that the velocity of the ionization wave is consistent with radiation driven thermal transport, exceeding the velocity expected from simple electron thermal conduction by nearly an order of magnitude. copyright 1996 The American Physical Society

  19. Pulsed-wave transmitral Doppler do not diagnose moderate acute rejection after heart transplantation

    NARCIS (Netherlands)

    Mannaerts, H. F.; Simoons, M. L.; Balk, A. H.; Tijssen, J.; van der Borden, S. G.; Zondervan, P. E.; Mochtar, B.; Weimar, W.; Roelandt, J. R.

    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

  20. 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

  1. Models of brachial to finger pulse wave distortion and pressure decrement

    NARCIS (Netherlands)

    Gizdulich, P.; Prentza, A.; Wesseling, K.H.

    1997-01-01

    Objective: To model the pulse wave distortion and pressure decrement occurring between brachial and finger arteries. Distortion reversion and decrement correction were also our aims. Methods: Brachial artery pressure was recorded intra-arterially and finger pressure was recorded non-invasively by

  2. Electrochemical Oxidation by Square-Wave Potential Pulses in the Imitation of Oxidative Drug Metabolism

    NARCIS (Netherlands)

    Nouri-Nigjeh, Eslam; Permentier, Hjalmar P.; Bischoff, Rainer; Bruins, Andries P.

    2011-01-01

    Electrochemistry combined with mass spectrometry (EC-MS) is an emerging analytical technique in the imitation of oxidative drug metabolism at the early stages of new drug development. Here, we present the benefits of electrochemical oxidation by square-wave potential pulses for the oxidation of

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

    International Nuclear Information System (INIS)

    Zhang, Shan; Hong, Xue-Ren; Wang, Hong-Yu; Xie, Bai-Song

    2011-01-01

    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.

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

    International Nuclear Information System (INIS)

    Clara, F M; Scandurra, A G; Meschino, G J; Passoni, L I

    2011-01-01

    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.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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

  6. Preparing isolated vibrational wave packets with light-induced molecular potentials by chirped laser pulses

    Science.gov (United States)

    Vatasescu, Mihaela

    2012-05-01

    We consider a specific wave packet preparation arising from the control of tunneling in the 0g-(6s,6p3/2) double well potential of a Cs2 cold molecule with chirped laser pulses. Such a possibility to manipulate the population dynamics in the 0g-(6s,6p3/2) potential appears in a pump-dump scheme designed to form cold molecules by photoassociation of two cold cesium atoms. The initial population in the 0g-(6s,6p3/2) double well is a wave packet prepared in the outer well at large interatomic distances (94 a0) by a photoassociation step with a first chirped pulse, being a superposition of several vibrational states whose energies surround the energy of a tunneling resonance. Our present work is focused on a second delayed chirped pulse, coupling the 0g-(6s,6p3/2) surface with the a3Σu+(6s,6s) one in the zone of the double well barrier (15 a0) and creating deeply bound cold molecules in the a3Σu+(6s,6s) state. We explore the parameters choice (intensity, duration, chirp rate and sign) for this second pulse, showing that picoseconds pulses with a negative chirp can lead to trapping of population in the inner well in strongly bound vibrational states, out of the resonant tunneling able to transfer it back to the outer well.

  7. Models of brachial to finger pulse wave distortion and pressure decrement.

    Science.gov (United States)

    Gizdulich, P; Prentza, A; Wesseling, K H

    1997-03-01

    To model the pulse wave distortion and pressure decrement occurring between brachial and finger arteries. Distortion reversion and decrement correction were also our aims. Brachial artery pressure was recorded intra-arterially and finger pressure was recorded non-invasively by the Finapres technique in 53 adult human subjects. Mean pressure was subtracted from each pressure waveform and Fourier analysis applied to the pulsations. A distortion model was estimated for each subject and averaged over the group. The average inverse model was applied to the full finger pressure waveform. The pressure decrement was modelled by multiple regression on finger systolic and diastolic levels. Waveform distortion could be described by a general, frequency dependent model having a resonance at 7.3 Hz. The general inverse model has an anti-resonance at this frequency. It converts finger to brachial pulsations thereby reducing average waveform distortion from 9.7 (s.d. 3.2) mmHg per sample for the finger pulse to 3.7 (1.7) mmHg for the converted pulse. Systolic and diastolic level differences between finger and brachial arterial pressures changed from -4 (15) and -8 (11) to +8 (14) and +8 (12) mmHg, respectively, after inverse modelling, with pulse pressures correct on average. The pressure decrement model reduced both the mean and the standard deviation of systolic and diastolic level differences to 0 (13) and 0 (8) mmHg. Diastolic differences were thus reduced most. Brachial to finger pulse wave distortion due to wave reflection in arteries is almost identical in all subjects and can be modelled by a single resonance. The pressure decrement due to flow in arteries is greatest for high pulse pressures superimposed on low means.

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

    International Nuclear Information System (INIS)

    Stuermer, E.; von Allmen, M.

    1978-01-01

    Drilling of highly reflective metals in an ambient atmosphere with single TEA-CO 2 -laser pulses of fluences between 300 and 6000 J/cm 2 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/cm 2 ), 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 TEM 00 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 cm 3 /J was observed in ambient helium at a laser fluence of 1 kJ/cm 2

  9. Wave Intensity Analysis of Right Ventricular Function during Pulsed Operation of Rotary Left Ventricular Assist Devices.

    Science.gov (United States)

    Bouwmeester, J Christopher; Park, Jiheum; Valdovinos, John; Bonde, Pramod

    2018-05-29

    Changing the speed of left ventricular assist devices (LVADs) cyclically may be useful to restore aortic pulsatility; however, the effects of this pulsation on right ventricular (RV) function are unknown. This study investigates the effects of direct ventricular interaction by quantifying the amount of wave energy created by RV contraction when axial and centrifugal LVADs are used to assist the left ventricle. In 4 anesthetized pigs, pressure and flow were measured in the main pulmonary artery and wave intensity analysis was used to identify and quantify the energy of waves created by the RV. The axial pump depressed the intensity of waves created by RV contraction compared with the centrifugal pump. In both pump designs, there were only minor and variable differences between the continuous and pulsed operation on RV function. The axial pump causes the RV to contract with less energy compared with a centrifugal design. Diminishing the ability of the RV to produce less energy translates to less pressure and flow produced, which may lead to LVAD-induced RV failure. The effects of pulsed LVAD operation on the RV appear to be minimal during acute observation of healthy hearts. Further study is necessary to uncover the effects of other modes of speed modulation with healthy and unhealthy hearts to determine if pulsed operation will benefit patients by reducing LVAD complications.

  10. Bright broadband coherent fiber sources emitting strongly blue-shifted resonant dispersive wave pulses

    DEFF Research Database (Denmark)

    Tu, Haohua; Lægsgaard, Jesper; Zhang, Rui

    2013-01-01

    We predict and realize the targeted wavelength conversion from the 1550-nm band of a fs Er:fiber laser to an isolated band inside 370-850 nm, corresponding to a blue-shift of 700-1180 nm. The conversion utilizes resonant dispersive wave generation in widely available optical fibers with good...... efficiency (~7%). The converted band has a large pulse energy (~1 nJ), high spectral brightness (~1 mW/nm), and broad Gaussian-like spectrum compressible to clean transform-limited ~17 fs pulses. The corresponding coherent fiber sources open up portable applications of optical parametric oscillators and dual......-output synchronized ultrafast lasers....

  11. Pulse-wave propagation in straight-geometry vessels for stiffness estimation: theory, simulations, phantoms and in vitro findings.

    Science.gov (United States)

    Shahmirzadi, Danial; Li, Ronny X; Konofagou, Elisa E

    2012-11-01

    Pulse wave imaging (PWI) is an ultrasound-based method for noninvasive characterization of arterial stiffness based on pulse wave propagation. Reliable numerical models of pulse wave propagation in normal and pathological aortas could serve as powerful tools for local pulse wave analysis and a guideline for PWI measurements in vivo. The objectives of this paper are to (1) apply a fluid-structure interaction (FSI) simulation of a straight-geometry aorta to confirm the Moens-Korteweg relationship between the pulse wave velocity (PWV) and the wall modulus, and (2) validate the simulation findings against phantom and in vitro results. PWI depicted and tracked the pulse wave propagation along the abdominal wall of canine aorta in vitro in sequential Radio-Frequency (RF) ultrasound frames and estimates the PWV in the imaged wall. The same system was also used to image multiple polyacrylamide phantoms, mimicking the canine measurements as well as modeling softer and stiffer walls. Finally, the model parameters from the canine and phantom studies were used to perform 3D two-way coupled FSI simulations of pulse wave propagation and estimate the PWV. The simulation results were found to correlate well with the corresponding Moens-Korteweg equation. A high linear correlation was also established between PWV² and E measurements using the combined simulation and experimental findings (R² =  0.98) confirming the relationship established by the aforementioned equation.

  12. The Effects of Hemodynamic Changes on Pulse Wave Velocity in Cardiothoracic Surgical Patients

    Directory of Open Access Journals (Sweden)

    Yurie Obata

    2016-01-01

    Full Text Available The effect of blood pressure on pulse wave velocity (PWV is well established. However, PWV variability with acute hemodynamic changes has not been examined in the clinical setting. The aim of the present study is to investigate the effect of hemodynamic changes on PWV in patients who undergo cardiothoracic surgery. Using data from 25 patients, we determined blood pressure (BP, heart rate (HR, and the left ventricular outflow tract (LVOT velocity-time integral. By superimposing the radial arterial waveform on the continuous wave Doppler waveform of the LVOT, obtained by transesophageal echo, we were able to determine pulse transit time and to calculate PWV, stroke volume (SV, cardiac output (CO, and systemic vascular resistance (SVR. Increases in BP, HR, and SVR were associated with higher values for PWV. In contrast increases in SV were associated with decreases in PWV. Changes in CO were not significantly associated with PWV.

  13. Pulse wave velocity 24-hour monitoring with one-site measurements by oscillometry

    Directory of Open Access Journals (Sweden)

    Posokhov IN

    2013-02-01

    Full Text Available Igor N PosokhovHemodynamic Laboratory Ltd, Nizhniy Novgorod, RussiaAbstract: This review describes issues for the estimation of pulse wave velocity (PWV under ambulatory conditions using oscillometric systems. The difference between the principles of measuring the PWV by the standard method and by oscillometry is shown, and information on device validation studies is summarized. It was concluded that currently oscillometry is a method that is very convenient to use in the 24-hour monitoring of the PWV, is relatively accurate, and is reasonably comfortable for the patient. Several indices with the same principles as those in the analysis of blood pressure in ambulatory monitoring of blood pressure, namely the assessment of load, variability, and circadian rhythm, are proposed.Keywords: pulse wave velocity, 24-hour monitoring, oscillometry

  14. Decreased memory loss associated with right unilateral ultra-brief pulse wave ECT.

    Science.gov (United States)

    Kim, Suck Won; Grant, Jon E; Rittberg, Barry R; Simon, John E; Vine, Craig J; Schulz, S Charles

    2007-01-01

    The purpose of this brief article is to share with our colleagues in the psychiatric community and other physicians information about the efficacy of an emerging new method of electroconvulsive therapy (ECT) that shows advantages over existing treatments for depression. Patients treated with the method, ultra-brief pulse wave ECT, have less memory loss and confusion than those treated with longer-duration ECT.

  15. Electric field measurements in a nanosecond pulse discharge by picosecond CARS/4-wave mixing

    Science.gov (United States)

    Goldberg, Ben; Shkurenkov, Ivan; Adamovich, Igor; Lempert, Walter

    2014-10-01

    Time-resolved electric field measurements in hydrogen by picosecond CARS/4-wave mixing are presented. Measurements are carried out in a high voltage nanosecond pulse discharge in hydrogen in plane-to-plane geometry, at pressures of up to several hundred Torr, and with a time resolution of 0.2 ns. Absolute calibration of the diagnostics is done using a sub-breakdown high voltage pulse of 12 kV/cm. A diffuse discharge is obtained by applying a peak high voltage pulse of 40 kV/cm between the electrodes. It is found that breakdown occurs at a lower field, 15--20 kV/cm, after which the field in the plasma is reduced rapidly due to plasma self shielding The experimental results are compared with kinetic modeling calculations, showing good agreement between the measured and the predicted electric field.

  16. Generation of spin waves by a train of fs-laser pulses: a novel approach for tuning magnon wavelength

    OpenAIRE

    Savochkin, I. V.; J?ckl, M.; Belotelov, V. I.; Akimov, I. A.; Kozhaev, M. A.; Sylgacheva, D. A.; Chernov, A. I.; Shaposhnikov, A. N.; Prokopov, A. R.; Berzhansky, V. N.; Yakovlev, D. R.; Zvezdin, A. K.; Bayer, M.

    2017-01-01

    Currently spin waves are considered for computation and data processing as an alternative to charge currents. Generation of spin waves by ultrashort laser pulses provides several important advances with respect to conventional approaches using microwaves. In particular, focused laser spot works as a point source for spin waves and allows for directional control of spin waves and switching between their different types. For further progress in this direction it is important to manipulate with ...

  17. Measurements of Electric Field in a Nanosecond Pulse Discharge by 4-WAVE Mixing

    Science.gov (United States)

    Baratte, Edmond; Adamovich, Igor V.; Simeni Simeni, Marien; Frederickson, Kraig

    2017-06-01

    Picosecond four-wave mixing is used to measure temporally and Picosecond four-wave mixing is used to measure temporally and spatially resolved electric field in a nanosecond pulse dielectric discharge sustained in room air and in an atmospheric pressure hydrogen diffusion flame. Measurements of the electric field, and more precisely the reduced electric field (E/N) in the plasma is critical for determination rate coefficients of electron impact processes in the plasma, as well as for quantifying energy partition in the electric discharge among different molecular energy modes. The four-wave mixing measurements are performed using a collinear phase matching geometry, with nitrogen used as the probe species, at temporal resolution of about 2 ns . Absolute calibration is performed by measurement of a known electrostatic electric field. In the present experiments, the discharge is sustained between two stainless steel plate electrodes, each placed in a quartz sleeve, which greatly improves plasma uniformity. Our previous measurements of electric field in a nanosecond pulse dielectric barrier discharge by picosecond 4-wave mixing have been done in air at room temperature, in a discharge sustained between a razor edge high-voltage electrode and a plane grounded electrode (a quartz plate or a layer of distilled water). Electric field measurements in a flame, which is a high-temperature environment, are more challenging because the four-wave mixing signal is proportional to the to square root of the difference betwen the populations of N2 ground vibrational level (v=0) and first excited vibrational level (v=1). At high temperatures, the total number density is reduced, thus reducing absolute vibrational level populations of N2. Also, the signal is reduced further due to a wider distribution of N2 molecules over multiple rotational levels at higher temperatures, while the present four-wave mixing diagnostics is using spectrally narrow output of a ps laser and a high

  18. [A quick algorithm of dynamic spectrum photoelectric pulse wave detection based on LabVIEW].

    Science.gov (United States)

    Lin, Ling; Li, Na; Li, Gang

    2010-02-01

    Dynamic spectrum (DS) detection is attractive among the numerous noninvasive blood component detection methods because of the elimination of the main interference of the individual discrepancy and measure conditions. DS is a kind of spectrum extracted from the photoelectric pulse wave and closely relative to the artery blood. It can be used in a noninvasive blood component concentration examination. The key issues in DS detection are high detection precision and high operation speed. The precision of measure can be advanced by making use of over-sampling and lock-in amplifying on the pick-up of photoelectric pulse wave in DS detection. In the present paper, the theory expression formula of the over-sampling and lock-in amplifying method was deduced firstly. Then in order to overcome the problems of great data and excessive operation brought on by this technology, a quick algorithm based on LabVIEW and a method of using external C code applied in the pick-up of photoelectric pulse wave were presented. Experimental verification was conducted in the environment of LabVIEW. The results show that by the method pres ented, the speed of operation was promoted rapidly and the data memory was reduced largely.

  19. 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  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.

  20. Pulsed Traveling-wave Quadrature Squeezing Using Quasi-phase Matched Lithium Niobate Crystals

    Science.gov (United States)

    Chen, Chao-Hsiang

    Interests in generating higher quantum noise squeezing in order to develop methods to enhance optical measurement below the shot-noise limit in various applications has grown in recent years. The noise suppression from squeezing can improve the SNR in coherent optical systems when the returning signal power is weak, such as optical coherence tomography, LADAR, confocal microscopy and low-light coherent imaging. Unlike the generation of squeezing with a continuous wave, which is currently developed mainly for gravitational wave detection in LIGO project, the study of pulsed-traveling waves is focused on industrial, medical and other commercial interests. This dissertation presents the experimental results of pulsed traveling wave squeezing. The intention of the study is to explore the possibility of using quasi-phase matched crystals to generate the highest possible degree of quadrature squeezing. In order to achieve this goal, efforts to test the various effects from spatial Gaussian modes and relative beam waist placement for the second-harmonic pump were carried out in order to further the understanding of limiting factors to pulsed traveling wave squeezing. 20mm and 30mm-long periodically poled lithium noibate (PPLN) crystals were used in the experiment to generate a squeezed vacuum state. A maximum of 4.2+/-0.2dB quadrature squeezing has been observed, and the measured anti-squeezing exceeds 20dB.The phase sensitive amplification (PSA) gain and de-gain performance were also measured to compare the results of measured squeezing. The PPLN crystals can produce high conversion efficiency of second-harmonic generation (SHG) without a cavity. When a long PPLN crystal is used in a squeezer, the beam propagation in the nonlinear medium does not follow the characteristics in thin crystals. Instead, it is operated under the long-crystal criteria, which the crystal length is multiple times longer than the Rayleigh range of the injected beam i n the crystals. Quasi

  1. Generalization of Bateman-Hillion progressive wave and Bessel-Gauss pulse solutions of the wave equation via a separation of variables

    CERN Document Server

    Kiselev, A

    2003-01-01

    Two new families of exact solutions of the wave equation u sub x sub x + u sub y sub y + u sub z sub z - c sup - sup 2 u sub t sub t = 0 generalizing Bessel-Gauss pulses and Bateman-Hillion relatively undistorted progressive waves, respectively are presented. In each of these families new simple solutions describing localized wave propagation are found. The approach is based on a kind of separation of variables. (letter to the editor)

  2. Pulmonary artery pulse pressure and wave reflection in chronic pulmonary thromboembolism and primary pulmonary hypertension.

    Science.gov (United States)

    Castelain, V; Hervé, P; Lecarpentier, Y; Duroux, P; Simonneau, G; Chemla, D

    2001-03-15

    The purpose of this time-domain study was to compare pulmonary artery (PA) pulse pressure and wave reflection in chronic pulmonary thromboembolism (CPTE) and primary pulmonary hypertension (PPH). Pulmonary artery pressure waveform analysis provides a simple and accurate estimation of right ventricular afterload in the time-domain. Chronic pulmonary thromboembolism and PPH are both responsible for severe pulmonary hypertension. Chronic pulmonary thromboembolism and PPH predominantly involve proximal and distal arteries, respectively, and may lead to differences in PA pressure waveform. High-fidelity PA pressure was recorded in 14 patients (7 men/7 women, 46 +/- 14 years) with CPTE (n = 7) and PPH (n = 7). We measured thermodilution cardiac output, mean PA pressure (MPAP), PA pulse pressure (PAPP = systolic - diastolic PAP) and normalized PAPP (nPAPP = PPAP/MPAP). Wave reflection was quantified by measuring Ti, that is, the time between pressure upstroke and the systolic inflection point (Pi), deltaP, that is, the systolic PAP minus Pi difference, and the augmentation index (deltaP/PPAP). At baseline, CPTE and PPH had similar cardiac index (2.4 +/- 0.4 vs. 2.5 +/- 0.5 l/min/m2), mean PAP (59 +/- 9 vs. 59 +/- 10 mm Hg), PPAP (57 +/- 13 vs. 53 +/- 13 mm Hg) and nPPAP (0.97 +/- 0.16 vs. 0.89 +/- 0.13). Chronic pulmonary thromboembolism had shorter Ti (90 +/- 17 vs. 126 +/- 16 ms, p PPAP (0.26 +/- 0.01 vs. 0.09 +/- 0.07, p < 0.01). Our study indicated that: 1) CPTE and PPH with severe pulmonary hypertension had similar PA pulse pressure, and 2) wave reflection is elevated in both groups, and CPTE had increased and anticipated wave reflection as compared with PPH, thus suggesting differences in the pulsatile component of right ventricular afterload.

  3. Noncontact sphygmomanometer based on pulse-wave transit time between the face and hand

    Science.gov (United States)

    Nakano, Kazuya; Ohnishi, Takashi; Nishidate, Izumi; Haneishi, Hideaki

    2018-02-01

    Systolic blood pressure (SBP) is highly sensitive to various factors such as psychological stress, and hence its continuous monitoring is essential to evaluate different health conditions. However, conventional sphygmomanometers cannot continuously measure SBP given the time-consuming setup based on a pressure cuff. Moreover, continuous biological signal monitoring is more comfortable when no sensors are attached. A solution for continuous SBP estimation is based on pulse transit time (PTT), which determines the time difference between two pulse waves at different body parts. In previous studies, we successfully measured the PTT using a contactless setup composed by two digital color cameras recording the face and hand of subjects. Then, the acquired images were transformed into blood volume by combining multiple regression analysis and a Monte Carlo method. As a result, the delay among images allowed to determine the PPT from pulse waves. In this study, we simultaneously measured SBP and PTT by using a sphygmomanometer and the two cameras, respectively. We evaluated SBP increases (i.e., stressful situations) and the corresponding PPT by asking participants to either grasp a handgrip or momentarily interrupting breath. We also determined the SBP and PTT without asking for such exercises. Comparison results show that the mean PTT under stress was significantly lower than that without stress, which is consistent with an increased SBP. Finally, we related the SBP and PTT by a nonlinear formula with a coefficient of determination of 0.59, thus confirming the effectiveness of the proposed system.

  4. 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.

  5. High-power TM01 millimeter wave pulse sensor in circular waveguide

    International Nuclear Information System (INIS)

    Wang Guang-Qiang; Zhu Xiang-Qin; Chen Zai-Gao; Wang Xue-Feng; Zhang Li-Jun

    2015-01-01

    By investigating the interaction of an n-type silicon sample with the TM 01 mode millimeter wave in a circular waveguide, a viable high-power TM 01 millimeter wave sensor is proposed. Based on the hot electron effect, the silicon sample serving as a sensing element (SE) and appropriately mounted on the inner wall of the circular waveguide is devoted to the on-line measurement of a high-power millimeter wave pulse. A three-dimensional parallel finite-difference time-domain method is applied to simulate the wave propagation within the measuring structure. The transverse electric field distribution, the dependences of the frequency response of the voltage standing-wave ratio (VSWR) in the circular waveguide, and the average electric field amplitude within the SE on the electrophysical parameters of the SE are calculated and analyzed in the frequency range of 300–400 GHz. As a result, the optimal dimensions and specific resistance of the SE are obtained, which provide a VSWR of no more than 2.0, a relative sensitivity around 0.0046 kW −1 fluctuating within ± 17.3%, and a maximum enduring power of about 4.3 MW. (paper)

  6. Analysis of pulse thermography using similarities between wave and diffusion propagation

    Science.gov (United States)

    Gershenson, M.

    2017-05-01

    Pulse thermography or thermal wave imaging are commonly used as nondestructive evaluation (NDE) method. While the technical aspect has evolve with time, theoretical interpretation is lagging. Interpretation is still using curved fitting on a log log scale. A new approach based directly on the governing differential equation is introduced. By using relationships between wave propagation and the diffusive propagation of thermal excitation, it is shown that one can transform from solutions in one type of propagation to the other. The method is based on the similarities between the Laplace transforms of the diffusion equation and the wave equation. For diffusive propagation we have the Laplace variable s to the first power, while for the wave propagation similar equations occur with s2. For discrete time the transformation between the domains is performed by multiplying the temperature data vector by a matrix. The transform is local. The performance of the techniques is tested on synthetic data. The application of common back projection techniques used in the processing of wave data is also demonstrated. The combined use of the transform and back projection makes it possible to improve both depth and lateral resolution of transient thermography.

  7. Generation of spin waves by a train of fs-laser pulses: a novel approach for tuning magnon wavelength.

    Science.gov (United States)

    Savochkin, I V; Jäckl, M; Belotelov, V I; Akimov, I A; Kozhaev, M A; Sylgacheva, D A; Chernov, A I; Shaposhnikov, A N; Prokopov, A R; Berzhansky, V N; Yakovlev, D R; Zvezdin, A K; Bayer, M

    2017-07-18

    Currently spin waves are considered for computation and data processing as an alternative to charge currents. Generation of spin waves by ultrashort laser pulses provides several important advances with respect to conventional approaches using microwaves. In particular, focused laser spot works as a point source for spin waves and allows for directional control of spin waves and switching between their different types. For further progress in this direction it is important to manipulate with the spectrum of the optically generated spin waves. Here we tackle this problem by launching spin waves by a sequence of femtosecond laser pulses with pulse interval much shorter than the relaxation time of the magnetization oscillations. This leads to the cumulative phenomenon and allows us to generate magnons in a specific narrow range of wavenumbers. The wavelength of spin waves can be tuned from 15 μm to hundreds of microns by sweeping the external magnetic field by only 10 Oe or by slight variation of the pulse repetition rate. Our findings expand the capabilities of the optical spin pump-probe technique and provide a new method for the spin wave generation and control.

  8. Numerical Investigation of Pulse Wave Propagation in Arteries Using Fluid Structure Interaction Capabilities

    Directory of Open Access Journals (Sweden)

    Hisham Elkenani

    2017-01-01

    Full Text Available The aim of this study is to present a reliable computational scheme to serve in pulse wave velocity (PWV assessment in large arteries. Clinicians considered it as an indication of human blood vessels’ stiffness. The simulation of PWV was conducted using a 3D elastic tube representing an artery. The constitutive material model specific for vascular applications was applied to the tube material. The fluid was defined with an equation of state representing the blood material. The onset of a velocity pulse was applied at the tube inlet to produce wave propagation. The Coupled Eulerian-Lagrangian (CEL modeling technique with fluid structure interaction (FSI was implemented. The scaling of sound speed and its effect on results and computing time is discussed and concluded that a value of 60 m/s was suitable for simulating vascular biomechanical problems. Two methods were used: foot-to-foot measurement of velocity waveforms and slope of the regression line of the wall radial deflection wave peaks throughout a contour plot. Both methods showed coincident results. Results were approximately 6% less than those calculated from the Moens-Korteweg equation. The proposed method was able to describe the increase in the stiffness of the walls of large human arteries via the PWV estimates.

  9. Experimental Observation of Generation of Superradiance Pulses in the Process of Backscattering of Pump Wave on the Intense Electron Bunch

    CERN Document Server

    Ginzburg, N S; Denisov, G G; Rozental, R M; Sergeev, A; Zotova, I V

    2005-01-01

    Recently significant progress was archived in the generation of multimegawatt subnanosecond pulses in millimeter wave band utilizing the cyclotron and Cherenkov mechanisms of superradiance (SR) [1,2]. We study the novel mechanism of SR when the powerful pumping wave undergoes the stimulated back scattering on the intense electron bunch. Due to the Doppler up shift the radiation frequency can significantly exceed the frequency of the pumping wave. With the relativistic microwave generator as a pumping wave source such a mechanism can be used for generation of the powerful pulse radiation in the short millimeter and submillimeter wave bands. Experiments on the observation of the stimulated scattering in the superradiance regime were carried out at Institute of Electrophysics RAS with two synchronized accelerators. The 4 ns electron beam from the first accelerator is used for generation of the 38 GHz 100 MW pumping wave which subsequently scattered on the subnanosecond 250 keV 1 kA electron bunch produced by the...

  10. 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.

  11. Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers.

    Science.gov (United States)

    Eigenwillig, Christoph M; Wieser, Wolfgang; Todor, Sebastian; Biedermann, Benjamin R; Klein, Thomas; Jirauschek, Christian; Huber, Robert

    2013-01-01

    Ultrafast lasers have a crucial function in many fields of science; however, up to now, high-energy pulses directly from compact, efficient and low-power semiconductor lasers are not available. Therefore, we introduce a new approach based on temporal compression of the continuous-wave, wavelength-swept output of Fourier domain mode-locked lasers, where a narrowband optical filter is tuned synchronously to the round-trip time of light in a kilometre-long laser cavity. So far, these rapidly swept lasers enabled orders-of-magnitude speed increase in optical coherence tomography. Here we report on the generation of ~60-70 ps pulses at 390 kHz repetition rate. As energy is stored optically in the long-fibre delay line and not as population inversion in the laser-gain medium, high-energy pulses can now be generated directly from a low-power, compact semiconductor-based oscillator. Our theory predicts subpicosecond pulses with this new technique in the future.

  12. Detection of leak-defective fuel rods using the circumferential Lamb waves excited by the resonance backscattering of ultrasonic pulses

    International Nuclear Information System (INIS)

    Choi, M.S.; Yang, M.S.; Kim, H.C.

    1992-01-01

    A new ultrasonic technique for detecting the infiltrated water in leaked fuel rods is developed. Propagation characteristics of the circumferential Lamb waves in the cladding tubes are estimated by the resonance scattering theory. The Lamb waves are excited by the resonance backscattering of ultrasonic pulses. In sound fuel rods, the existence of the Lamb waves is revealed by a series of periodic echoes. In leaked fuel rods, however, the Lamb waves are perturbed strongly by the scattered waves from the surface of fuel pellets, thus the periodic echoes are not observed. (author)

  13. Acute effects of interval versus continuous endurance training on pulse wave reflection in healthy young men.

    Science.gov (United States)

    Hanssen, Henner; Nussbaumer, Monique; Moor, Christoph; Cordes, Mareike; Schindler, Christian; Schmidt-Trucksäss, Arno

    2015-02-01

    Our aim was to investigate the acute and 24-hour (h) effects of high-intensity interval training (HIIT) and moderate continuous training (MCT) on arterial pulse wave reflection, an established marker of arterial stiffness and cardiovascular risk. In a randomized cross-over design, 21 young healthy male participants performed a HIIT or a MCT on separate visits. Before and 5 (t5), 20 (t20), 35 (t35), and 50 (t50) minutes after the acute exercise bouts, the crude augmentation index (AIx) and the AIx at a set heart rate (AIx@75) were analysed by applanation tonometry. Starting 1 h post-exercise, both indices were captured over 24-h with an oscillometric monitoring device. AIx did not change significantly after MCT but declined progressively after HIIT, reaching significantly lower values compared to MCT at t35 (P = 0.045) and t50 (P = 0.008). AIx@75 increased after both acute exercise types but was higher after HIIT at t5 (P HIIT (P = 0.007) but not after MCT (P = 0.813). Exercise intensity affects pulse wave reflection, with different time courses for AIx and AIx@75 post-exercise. Although initially higher after HIIT, AIx@75 declines in the 24-h recovery period indicating more favourable effects on pulse wave reflection compared to MCT. This may result in substantial positive chronic training effects on arterial stiffness in health and cardiovascular disease. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Effect of Shock Waves Generated by Pulsed Electric Discharges in Water on Yeast Cells and Virus Particles

    Science.gov (United States)

    Girdyuk, A. E.; Gorshkov, A. N.; Egorov, V. V.; Kolikov, V. A.; Snetov, V. N.; Shneerson, G. A.

    2018-02-01

    The aim of this study is to determine the optimal parameters of the electric pulses and shock waves generated by them for the soft destruction of the virus and yeast envelopes with no changes in the structure of antigenic surface albumin and in the cell morphology in order to use them to produce antivirus vaccines and in biotechnology. The pulse electric discharges in water have been studied for different values of amplitude, pulse duration and the rate of the rise in the current. A mathematical model has been developed to estimate the optimal parameters of pulsed electric charges and shock waves for the complete destruction of the yeast cell envelopes and virus particles at a minimum of pulses.

  15. 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.

  16. Pulse Wave Velocity Measuring System using Virtual Instrumentation on Mobile Device

    Directory of Open Access Journals (Sweden)

    Razvan Alin Ciobotariu

    2013-03-01

    Full Text Available Virtual instrumentation is a concept that permits customizable modular software measurement and the development of the user-defined tools for control, process and visualization of data, creating versatile systems, using modular programming, intuitive and easy to use. In this paper we investigate a possibility of using virtual instrumentation in the development of two physiological parameters monitoring system, in order to assess a cardiovascular parameter, the Pulse Wave Velocity (PWV. We choose to monitor this parameter due to major incidence and impact of cardiovascular diseases (CVD.

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

    Science.gov (United States)

    Zajnulina, M.; Böhm, M.; Blow, K.; Rieznik, A. A.; Giannone, D.; Haynes, R.; Roth, M. M.

    2015-10-01

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

    International Nuclear Information System (INIS)

    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. (topical review)

  19. 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.

  20. A pulse coding and decoding strategy to perform Lamb wave inspections using simultaneously multiple actuators

    Science.gov (United States)

    De Marchi, Luca; Marzani, Alessandro; Moll, Jochen; Kudela, Paweł; Radzieński, Maciej; Ostachowicz, Wiesław

    2017-07-01

    The performance of Lamb wave based monitoring systems, both in terms of diagnosis time and data complexity, can be enhanced by increasing the number of transducers used to actuate simultaneously the guided waves in the inspected medium. However, in case of multiple simultaneously-operated actuators the interference among the excited wave modes within the acquired signals has to be considered for the further processing. To this aim, in this work a code division strategy based on the Warped Frequency Transform is presented. At first, the proposed procedure encodes actuation pulses using Gold sequences. Next, for each considered actuator the acquired signals are compensated from dispersion by cross correlating the warped version of the actuated and received signals. Compensated signals form the base for a final wavenumber imaging meant at emphasizing defects and or anomalies by removing incident wavefield and edge reflections. The proposed strategy is tested numerically, and validated through an experiment in which guided waves are actuated in a plate by four piezoelectric transducers operating simultaneously.

  1. Normal Reflection Characteristics of One-Dimensional Unsteady Flow Shock Waves on Rigid Walls from Pulse Discharge in Water

    Directory of Open Access Journals (Sweden)

    Dong Yan

    2017-01-01

    Full Text Available Strong shock waves can be generated by pulse discharge in water, and the characteristics due to the shock wave normal reflection from rigid walls have important significance to many fields, such as industrial production and defense construction. This paper investigates the effects of hydrostatic pressures and perturbation of wave source (i.e., charging voltage on normal reflection of one-dimensional unsteady flow shock waves. Basic properties of the incidence and reflection waves were analyzed theoretically and experimentally to identify the reflection mechanisms and hence the influencing factors and characteristics. The results indicated that increased perturbation (i.e., charging voltage leads to increased peak pressure and velocity of the reflected shock wave, whereas increased hydrostatic pressure obviously inhibited superposition of the reflection waves close to the rigid wall. The perturbation of wave source influence on the reflected wave was much lower than that on the incident wave, while the hydrostatic pressure obviously affected both incident and reflection waves. The reflection wave from the rigid wall in water exhibited the characteristics of a weak shock wave, and with increased hydrostatic pressure, these weak shock wave characteristics became more obvious.

  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. Amplification of pressure waves in laser-assisted endodontics with synchronized delivery of Er:YAG laser pulses.

    Science.gov (United States)

    Lukač, Nejc; Jezeršek, Matija

    2018-05-01

    When attempting to clean surfaces of dental root canals with laser-induced cavitation bubbles, the resulting cavitation oscillations are significantly prolonged due to friction on the cavity walls and other factors. Consequently, the collapses are less intense and the shock waves that are usually emitted following a bubble's collapse are diminished or not present at all. A new technique of synchronized laser-pulse delivery intended to enhance the emission of shock waves from collapsed bubbles in fluid-filled endodontic canals is reported. A laser beam deflection probe, a high-speed camera, and shadow photography were used to characterize the induced photoacoustic phenomena during synchronized delivery of Er:YAG laser pulses in a confined volume of water. A shock wave enhancing technique was employed which consists of delivering a second laser pulse at a delay with regard to the first cavitation bubble-forming laser pulse. Influence of the delay between the first and second laser pulses on the generation of pressure and shock waves during the first bubble's collapse was measured for different laser pulse energies and cavity volumes. Results show that the optimal delay between the two laser pulses is strongly correlated with the cavitation bubble's oscillation period. Under optimal synchronization conditions, the growth of the second cavitation bubble was observed to accelerate the collapse of the first cavitation bubble, leading to a violent collapse, during which shock waves are emitted. Additionally, shock waves created by the accelerated collapse of the primary cavitation bubble and as well of the accompanying smaller secondary bubbles near the cavity walls were observed. The reported phenomena may have applications in improved laser cleaning of surfaces during laser-assisted dental root canal treatments.

  4. Spectral broadening measurement of the lower hybrid waves during long pulse operation in Tore Supra

    Science.gov (United States)

    Berger-By, G.; Decampy, J.; Antar, G. Y.; Goniche, M.; Ekedahl, A.; Delpech, L.; Leroux, F.; Tore Supra Team

    2014-02-01

    On many tokamaks (C-Mod, EAST, FTU, JET, HT-7, TS), a decrease in current drive efficiency of the Lower Hybrid (LH) waves is observed in high electron density plasmas. The cause of this behaviour is believed to be: Parametric Instabilities (PI) and Scattering from Density Fluctuations (SDF). For the ITER LH system, our knowledge must be improved to avoid such effects and to maintain the LH current drive efficiency at high density. The ITPA IOS group coordinates this effort [1] and all experimental data are essential to validate the numerical codes in progress. Usually the broadening of the LH wave frequency spectrum is measured by a probe located in the plasma edge. For this study, the frequency spectrum of a reflected power signal from the LH antenna was used. In addition, the spectrum measurements are compared with the density fluctuations observed on RF probes located at the antenna mouth. Several plasma currents (0.6 to 1.4 MA) and densities up to 5.2 × 1019 m-3 have been realised on Tore Supra (TS) long pulses and with high injected RF power, up to 5.4 MW-30s. This allowed using a spectrum analyser to make several measurements during the plasma pulse. The side lobe amplitude, shifted by 20-30MHz with respect to the main peak, grows with increasing density. Furthermore, for an increase of plasma current at the same density, the spectra broaden and become asymmetric. Some parametric dependencies are shown in this paper.

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

    Directory of Open Access Journals (Sweden)

    Bharti Chawre

    2018-06-01

    Full Text Available Physico-mechanical properties are critically important parameters for rocks. This study aims to examine some of the rock properties of quartz-mica schist (QMS rocks in a cost-effective manner by establishing correlations between non-destructive and destructive tests. Using simple regression analysis, good correlations were obtained between the pulse wave velocities and the properties of QMS rocks. The results were further improved by using multiple regression analysis as compared to those obtained by the simple linear regression analysis. The results were also compared to the ones obtained by other empirical equations available. The general equations encompassing all types of rocks did not give reliable results of rock properties and showed large relative errors, ranging from 23% to 1146%. It is suggested that empirical correlations must be investigated separately for different types of rocks. The general empirical equations should not be used for the design and planning purposes before they are verified at least on one rock sample from the project site, as they may contain large unacceptable errors. Keywords: Pulse wave velocity, Physico-mechanical properties, Quartz-mica schist (QMS rocks, Non-destructive methods, Static elastic constants, Dynamic elastic constants

  6. Pulse wave velocity is associated with cognitive impairment in hemodialysis patients.

    Science.gov (United States)

    Angermann, Susanne; Baumann, Marcus; Wassertheurer, Siegfried; Mayer, Christopher Clemens; Steubl, Dominik; Hauser, Christine; Suttmann, Yana; Reichelt, Anna-Lena; Satanovskij, Robin; Lorenz, Georg; Lukas, Moritz; Haller, Bernhard; Heemann, Uwe; Grimmer, Timo; Schmaderer, Christoph

    2017-07-01

    Cognitive impairment in hemodialysis patients is common and associated with adverse outcomes. So far, the underlying pathogenesis remains unclear. Therefore, we examined the potential relationship between cognitive impairment and three different categories of risk factors with particular focus on arterial stiffness measured by pulse wave velocity (PWV). A total of 201 chronic hemodialysis patients underwent cognitive testing under standardized conditions using the Montreal Cognitive Assessment (MoCA). Demographic data including cardiovascular risk factors, dialysis-associated factors as well as factors related to chronic kidney disease (CKD) were analyzed. To account for arterial stiffness, PWV was measured by ambulatory blood pressure monitoried with an oscillometric device that records brachial blood pressure along with pulse waves. In our cohort, 60.2% of patients showed pathological MoCA test results indicating cognitive impairment. PWV was significantly associated with cognitive impairment apart from age, educational level, diabetes, and hypercholesterolemia. High prevalence of cognitive impairment in hemodialysis patients was confirmed. For the first time, an association between cognitive impairment and arterial stiffness was detected in a larger cohort of hemodialysis patients. Concerning the underlying pathogenesis of cognitive impairment, current results revealed a potential involvement of arterial stiffness, which has to be further evaluated in future studies. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  7. Control of propagation characteristics of spin wave pulses via elastic and thermal effects

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Arista, Ivan [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, CU, 04510 D.F., México (Mexico); Kolokoltsev, O., E-mail: oleg.kolokoltsev@ccadet.unam.mx [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, CU, 04510 D.F., México (Mexico); Acevedo, A.; Qureshi, N. [Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México, CU, 04510 D.F., México (Mexico); Ordóñez-Romero, César L. [Instituto de Física, Universidad Nacional Autónoma de México, CU, 04510 D.F., México (Mexico)

    2017-05-01

    A study of the magnetoelastic (ME) and thermal effects governing the phase (φ) and amplitude of magnetostatic surface spin wave (MSSW) pulses propagating in Ga:YIG/GGG and permalloy magnonic waveguides is presented. The ME effects were studied in a flexural configuration, under punctual mechanical force (F). Thermally induced ME and demagnetization phenomena were controlled by optically injected thermal power P{sub th}. It was determined that in an unclamped Ga:YIG waveguide, the force F that induces the phase shift Δφ=π, decreases by a quadratic law in the range from 1 mN to nN, and the P{sub th} at which Δφ=π decreases linearly from mW to μW as the waveguide volume decreases from mm{sup 3} to nm{sup 3}. For nano-volume waveguides the ME control energy (E{sub me}) can be of order of aJ, and the thermal control energy (ΔE{sub th}) can be as small as 50 fJ. The response time of these effects lies in the ns time scale. Both the mechanical and the thermo-magnetic forces provide an effective control of MSSW pulse amplitude, in addition to its phase shift. The thermo-magnetic effect allows one to realize variable delays of a MSSW pulse. - Highlights: • The Magneto-elastic (ME) and optically induced thermal effects governing the phase and amplitude of magnetostatic surface spin wave (MSSW) pulses propagating in Ga:YIG/GGG and permalloy magnonic waveguides are presented. • A mechanical force that causes phase shift Δφ=π for spin waves in the waveguides decreases by a quadratic law in the range from 1 mN to nN, and the optical power that induces the phase shift Δφ=π, decreases linearly from mW to μW as the waveguide volume decreases from mm{sup 3} to nm{sup 3}. • The response time of these effects can lie in the ns time scale.

  8. 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.

  9. 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.

  10. Acoustic pressure waves induced in human heads by RF pulses from high-field MRI scanners.

    Science.gov (United States)

    Lin, James C; Wang, Zhangwei

    2010-04-01

    The current evolution toward greater image resolution from magnetic resonance image (MRI) scanners has prompted the exploration of higher strength magnetic fields and use of higher levels of radio frequencies (RFs). Auditory perception of RF pulses by humans has been reported during MRI with head coils. It has shown that the mechanism of interaction for the auditory effect is caused by an RF pulse-induced thermoelastic pressure wave inside the head. We report a computational study of the intensity and frequency of thermoelastic pressure waves generated by RF pulses in the human head inside high-field MRI and clinical scanners. The U.S. Food and Drug Administration (U.S. FDA) guides limit the local specific absorption rate (SAR) in the body-including the head-to 8 W kg(-1). We present results as functions of SAR and show that for a given SAR the peak acoustic pressures generated in the anatomic head model were essentially the same at 64, 300, and 400 MHz (1.5, 7.0, and 9.4 T). Pressures generated in the anatomic head are comparable to the threshold pressure of 20 mPa for sound perception by humans at the cochlea for 4 W kg(-1). Moreover, results indicate that the peak acoustic pressure in the brain is only 2 to 3 times the auditory threshold at the U.S. FDA guideline of 8 W kg(-1). Even at a high SAR of 20 W kg(-1), where the acoustic pressure in the brain could be more than 7 times the auditory threshold, the sound pressure levels would not be more than 17 db above threshold of perception at the cochlea.

  11. 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

  12. The association between pulse wave velocity and cognitive function: the Sydney Memory and Ageing Study.

    Directory of Open Access Journals (Sweden)

    Joel Singer

    Full Text Available OBJECTIVES: Pulse wave velocity (PWV is a measure of arterial stiffness and its increase with ageing has been associated with damage to cerebral microvessels and cognitive impairment. This study examined the relationship between carotid-femoral PWV and specific domains of cognitive function in a non-demented elderly sample. METHOD: Data were drawn from the Sydney Memory and Ageing Study, a cohort study of non-demented community-dwelling individuals aged 70-90 years, assessed in successive waves two years apart. In Wave 2, PWV and cognitive function were measured in 319 participants. Linear regression was used to analyse the cross-sectional relationship between arterial stiffness and cognitive function in the whole sample, and separately for men and women. Analysis of covariance was used to assess potential differences in cognition between subjects with PWV measurements in the top and bottom tertiles of the cohort. Covariates were age, education, body mass index, pulse rate, systolic blood pressure, cholesterol, depression, alcohol, smoking, hormone replacement therapy, apolipoprotein E ε4 genotype, use of anti-hypertensive medications, history of stroke, transient ischemic attack, myocardial infarction, angina, diabetes, and also sex for the whole sample analyses. RESULTS: There was no association between PWV and cognition after Bonferroni correction for multiple testing. When examining this association for males and females separately, an association was found in males, with higher PWV being associated with lower global cognition and memory, however, a significant difference between PWV and cognition between males and females was not found. CONCLUSION: A higher level of PWV was not associated with lower cognitive function in the whole sample.

  13. The association between pulse wave velocity and cognitive function: the Sydney Memory and Ageing Study.

    Science.gov (United States)

    Singer, Joel; Trollor, Julian N; Crawford, John; O'Rourke, Michael F; Baune, Bernhard T; Brodaty, Henry; Samaras, Katherine; Kochan, Nicole A; Campbell, Lesley; Sachdev, Perminder S; Smith, Evelyn

    2013-01-01

    Pulse wave velocity (PWV) is a measure of arterial stiffness and its increase with ageing has been associated with damage to cerebral microvessels and cognitive impairment. This study examined the relationship between carotid-femoral PWV and specific domains of cognitive function in a non-demented elderly sample. Data were drawn from the Sydney Memory and Ageing Study, a cohort study of non-demented community-dwelling individuals aged 70-90 years, assessed in successive waves two years apart. In Wave 2, PWV and cognitive function were measured in 319 participants. Linear regression was used to analyse the cross-sectional relationship between arterial stiffness and cognitive function in the whole sample, and separately for men and women. Analysis of covariance was used to assess potential differences in cognition between subjects with PWV measurements in the top and bottom tertiles of the cohort. Covariates were age, education, body mass index, pulse rate, systolic blood pressure, cholesterol, depression, alcohol, smoking, hormone replacement therapy, apolipoprotein E ε4 genotype, use of anti-hypertensive medications, history of stroke, transient ischemic attack, myocardial infarction, angina, diabetes, and also sex for the whole sample analyses. There was no association between PWV and cognition after Bonferroni correction for multiple testing. When examining this association for males and females separately, an association was found in males, with higher PWV being associated with lower global cognition and memory, however, a significant difference between PWV and cognition between males and females was not found. A higher level of PWV was not associated with lower cognitive function in the whole sample.

  14. Steering wave packet dynamics and population transfer between electronic states of the Na2 molecule by femtosecond laser pulses

    International Nuclear Information System (INIS)

    Yuan Kaijun; Sun Zhigang; Cong Shulin; Wang Senming; Yu Jie; Lou Nanquan

    2005-01-01

    An approach used for steering the wave packet dynamics and the population transfer between electronic states of the Na 2 molecule by a pair of femtosecond laser pulses is demonstrated. Four controlling schemes, i.e., four different combinations of time delays (intuitive and counterintuitive sequences) and frequency detunings (positive and negative detunings), are discussed in detail. The light-induced potentials are used to describe the wave packet dynamics and population transfer. The numerical results show that the wave packet excited by femtosecond laser pulses oscillates drastically on 2 1 Π g state with time. The efficiency of controlling population transfer from the X 1 Σ g + to2 1 Π g states of Na 2 is nearly 100% for the schemes of the counterintuitive sequence pulses with positive and negative detunings

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

    International Nuclear Information System (INIS)

    Guerreiro, Gabriela V.; Zaitouna, Anita J.; Lai, Rebecca Y.

    2014-01-01

    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 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 2+ rather rapidly; majority of the signal change occurred in 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

  16. Thermal wave propagation in the pulsed laser irradiation of media with thermal memory

    International Nuclear Information System (INIS)

    Galovic, S.; Kostoski, D.; Stamboliev, G.; Suljovrujic, E.

    2002-01-01

    Complete text of publication follows. If a sample is exposed to the influence of laser radiation part of its energy is absorbed and converted in heat. The heat generated in this way is transferred through the sample as heat waves, resulting in various effects (so called photothermal effects). A large number of nondestructive diagnostic methods are based on recording of these effects. It is necessary to create a good model in order to understand and correctly describe the measured results of heat transfer in different media. In a certain number of materials and structures, such as complex biological materials, polymers, metals excited by very short laser pulses etc., the property of thermal memory has been experimentally observed. Starting with the hyperbolic equation that describes heat transfer processes of such media, in this paper has been developed a model of laser-excited heat waves propagation in order to enable application of photothermal techniques in characterization of these media. The cases of optically opaque and transparent samples are considered. The influence of various backings on photothermal waves has also been analyzed. The results are compared to the previous models

  17. Ionospheric cusp flows pulsed by solar wind Alfvén waves

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    P. Prikryl

    2002-02-01

    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

  18. 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

  19. Tracking nuclear wave-packet dynamics in molecular oxygen ions with few-cycle infrared laser pulses

    International Nuclear Information System (INIS)

    De, S.; Bocharova, I. A.; Magrakvelidze, M.; Ray, D.; Cao, W.; Thumm, U.; Cocke, C. L.; Bergues, B.; Kling, M. F.; Litvinyuk, I. V.

    2010-01-01

    We have tracked nuclear wave-packet dynamics in doubly charged states of molecular oxygen using few-cycle infrared laser pulses. Bound and dissociating wave packets were launched and subsequently probed via a pair of 8-fs pulses of 790 nm radiation. Ionic fragments from the dissociating molecules were monitored by velocity-map imaging. Pronounced oscillations in the delay-dependent kinetic energy release spectra were observed. The occurrence of vibrational revivals permits us to identify the potential curves of the O 2 dication which are most relevant to the molecular dynamics. These studies show the accessibility to the dynamics of such higher-charged molecules.

  20. Frequency modulation and compression of optical pulses in an optical fibre with a travelling refractive-index wave

    Energy Technology Data Exchange (ETDEWEB)

    Zolotovskii, I O; Lapin, V A; Sementsov, D I [Ulyanovsk State University, Ulyanovsk (Russian Federation)

    2016-01-31

    We have studied the conditions for spectral broadening, frequency modulation and compression (both temporal and spectral) of Gaussian pulses propagating in a fibre with a travelling refractive-index wave. Analytical expressions have been derived for the dependences of pulse duration, chirp and spectral width on the distance travelled through the fibre, parameters of the fibre and radiation launched into it. Based on the numerical analysis we have studied the behaviour of these characteristics by changing the coefficient of the refractive-index modulation and other parameters of the travelling refractive-index wave. (nonlinear optical phenomena)

  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. Following dynamic nuclear wave packets in N2,O2, and CO with few-cycle infrared pulses

    International Nuclear Information System (INIS)

    De, S.; Magrakvelidze, M.; Bocharova, I. A.; Ray, D.; Cao, W.; Li, H.; Wang, Z.; Laurent, G.; Thumm, U.; Ben-Itzhak, I.; Cocke, C. L.; Znakovskaya, I.; Kling, M. F.; Litvinyuk, I. V.

    2011-01-01

    We study the evolution of nuclear wave packets launched in molecular nitrogen, oxygen, and carbon monoxide by intense 8-fs infrared pulses. We use velocity map imaging to measure the momentum of the ion fragments when these wave packets are interrogated by a second such pulse after a variable time delay. Both quasibound and dissociative wave packets are observed. For the former, measurements of bound-state oscillations are used to identify the participating states and, in some cases, extract properties of the relevant potential-energy surfaces. Vibrational structure is resolved in both energy and oscillation frequencies for the cations of oxygen and carbon monoxide, displaying the same quantum wave-packet motion in both energy and time domains. In addition, vibrational structure is seen in the dication of carbon monoxide in a situation where the energy resolution by itself is inadequate to resolve the structure.

  3. Following dynamic nuclear wave packets in N2,O2, and CO with few-cycle infrared pulses

    Science.gov (United States)

    de, S.; Magrakvelidze, M.; Bocharova, I. A.; Ray, D.; Cao, W.; Znakovskaya, I.; Li, H.; Wang, Z.; Laurent, G.; Thumm, U.; Kling, M. F.; Litvinyuk, I. V.; Ben-Itzhak, I.; Cocke, C. L.

    2011-10-01

    We study the evolution of nuclear wave packets launched in molecular nitrogen, oxygen, and carbon monoxide by intense 8-fs infrared pulses. We use velocity map imaging to measure the momentum of the ion fragments when these wave packets are interrogated by a second such pulse after a variable time delay. Both quasibound and dissociative wave packets are observed. For the former, measurements of bound-state oscillations are used to identify the participating states and, in some cases, extract properties of the relevant potential-energy surfaces. Vibrational structure is resolved in both energy and oscillation frequencies for the cations of oxygen and carbon monoxide, displaying the same quantum wave-packet motion in both energy and time domains. In addition, vibrational structure is seen in the dication of carbon monoxide in a situation where the energy resolution by itself is inadequate to resolve the structure.

  4. 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...... 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....

  5. Pulse wave velocity as a diagnostic index: The effect of wall thickness

    Science.gov (United States)

    Hodis, Simona

    2018-06-01

    Vascular compliance is a major determinant of wave propagation within the vascular system, and hence the measurement of pulse wave velocity (PWV) is commonly used clinically as a method of detecting vascular stiffening. The accuracy of that assessment is important because vascular stiffening is a major risk factor for hypertension. PWV is usually measured by timing a pressure wave as it travels from the carotid artery to the femoral or radial artery and estimating the distance that it traveled in each case to obtain the required velocity. A major assumption on which this technique is based is that the vessel wall thickness h is negligibly small compared with the vessel radius a . The extent to which this assumption is satisfied in the cardiovascular system is not known because the ratio h /a varies widely across different regions of the vascular tree and under different pathological conditions. Using the PWV as a diagnostic test without knowing the effect of wall thickness on the measurement could lead to error when interpreting the PWV value as an index of vessel wall compliance. The aim of the present study was to extend the validity of the current practice of assessing wall stiffness by developing a method of analysis that goes beyond the assumption of a thin wall. We analyzed PWVs calculated with different wall models, depending on the ratio of wall thickness to vessel radius and the results showed that PWV is not reliable when it is estimated with the classic thin wall theory if the vessel wall is not around 25% of vessel radius. If the arterial wall is thicker than 25% of vessel radius, then the wave velocity calculated with the thin wall theory could be overestimated and in the clinical setting, this could lead to a false positive. For thicker walls, a thick wall model presented here should be considered to account for the stresses within the wall thickness that become dominant compared with the wall inertia.

  6. Artificial Intelligence Estimation of Carotid-Femoral Pulse Wave Velocity using Carotid Waveform.

    Science.gov (United States)

    Tavallali, Peyman; Razavi, Marianne; Pahlevan, Niema M

    2018-01-17

    In this article, we offer an artificial intelligence method to estimate the carotid-femoral Pulse Wave Velocity (PWV) non-invasively from one uncalibrated carotid waveform measured by tonometry and few routine clinical variables. Since the signal processing inputs to this machine learning algorithm are sensor agnostic, the presented method can accompany any medical instrument that provides a calibrated or uncalibrated carotid pressure waveform. Our results show that, for an unseen hold back test set population in the age range of 20 to 69, our model can estimate PWV with a Root-Mean-Square Error (RMSE) of 1.12 m/sec compared to the reference method. The results convey the fact that this model is a reliable surrogate of PWV. Our study also showed that estimated PWV was significantly associated with an increased risk of CVDs.

  7. 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.

  8. Spin effects in nonlinear Compton scattering in a plane-wave laser pulse

    International Nuclear Information System (INIS)

    Boca, Madalina; Dinu, Victor; Florescu, Viorica

    2012-01-01

    We study theoretically the electron angular and energy distribution in the non-linear Compton effect in a finite plane-wave laser pulse. We first present analytical and numerical results for unpolarized electrons (described by a Volkov solution of the Dirac equation), in comparison with those corresponding to a spinless particle (obeying the Klein–Gordon equation). Then, in the spin 1/2 case, we include results for the spin flip probability. The regime in which the spin effects are negligible, i.e. the results for the unpolarized spin 1/2 particle coincide practically with those for the spinless particle, is the same as the regime in which the emitted radiation is well described by classical electrodynamics.

  9. Pulse wave as an alternate signal for data synchronization during gated myocardial perfusion SPECT imaging.

    Science.gov (United States)

    Lang, Otto; Trojanova, Helena; Balon, Helena R; Kunikova, Ivana; Bilwachs, Milos; Penicka, Martin; Kaminek, Milan; Myslivecek, Miroslav

    2011-09-01

    Proper identification of the cardiac cycle is essential for gated SPECT myocardial perfusion imaging. We have developed an alternate method of ECG for gating, that is, using the peripheral pulse wave (PW) as the triggering signal for gated SPECT acquisition. The aim of this study is to compare the use of this method of gating with the standard ECG trigger. We tested the PW triggering by comparing it with the ECG trigger. We evaluated 33 patients (25 males, 8 females), average age of 61 years (39-80) referred for stress myocardial perfusion imaging. Data from all patients were acquired twice and were processed by CEqual and QGS software. We compared the left ventricular ejection fraction (LVEF), end-diastolic and end-systolic volumes (EDV, ESV). Paired t test and Pearson correlation coefficient were used for comparison. The mean LVEF, EDV, and ESV calculated with the ECG trigger were 0.52, 120, and 64, respectively, those with the pulse-wave trigger were 0.48, 126, and 71, respectively. Mean paired difference for LVEF was -0.034 (P<0.001), for EDV 5.9 (P=0.012), and for ESV 7.9 (P<0.001). Pearson correlation coefficient for LVEF was 0.955, for EDV 0.987, and for ESV 0.991 (P<0.001 for all correlations). Triggering of gated-data acquisition by the PW is feasible. Quantitative parameters of cardiac function correlate highly with those obtained from the ECG trigger and the absolute differences are not clinically significant across a wide range of values.

  10. Pilot Study: Estimation of Stroke Volume and Cardiac Output from Pulse Wave Velocity.

    Directory of Open Access Journals (Sweden)

    Yurie Obata

    Full Text Available Transesophageal echocardiography (TEE is increasingly replacing thermodilution pulmonary artery catheters to assess hemodynamics in patients at high risk for cardiovascular morbidity. However, one of the drawbacks of TEE compared to pulmonary artery catheters is the inability to measure real time stroke volume (SV and cardiac output (CO continuously. The aim of the present proof of concept study was to validate a novel method of SV estimation, based on pulse wave velocity (PWV in patients undergoing cardiac surgery.This is a retrospective observational study. We measured pulse transit time by superimposing the radial arterial waveform onto the continuous wave Doppler waveform of the left ventricular outflow tract, and calculated SV (SVPWV using the transformed Bramwell-Hill equation. The SV measured by TEE (SVTEE was used as a reference.A total of 190 paired SV were measured from 28 patients. A strong correlation was observed between SVPWV and SVTEE with the coefficient of determination (R2 of 0.71. A mean difference between the two (bias was 3.70 ml with the limits of agreement ranging from -20.33 to 27.73 ml and a percentage error of 27.4% based on a Bland-Altman analysis. The concordance rate of two methods was 85.0% based on a four-quadrant plot. The angular concordance rate was 85.9% with radial limits of agreement (the radial sector that contained 95% of the data points of ± 41.5 degrees based on a polar plot.PWV based SV estimation yields reasonable agreement with SV measured by TEE. Further studies are required to assess its utility in different clinical situations.

  11. 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).

  12. Spectral broadening measurement of the lower hybrid waves during long pulse operation in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Berger-By, G.; Decampy, J.; Goniche, M.; Ekedahl, A.; Delpech, L.; Leroux, F. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Antar, G. Y. [American University of Beirut, Riad el-Solh, Beirut 1107-2020 (Lebanon); Collaboration: Tore Supra Team

    2014-02-12

    On many tokamaks (C-Mod, EAST, FTU, JET, HT-7, TS), a decrease in current drive efficiency of the Lower Hybrid (LH) waves is observed in high electron density plasmas. The cause of this behaviour is believed to be: Parametric Instabilities (PI) and Scattering from Density Fluctuations (SDF). For the ITER LH system, our knowledge must be improved to avoid such effects and to maintain the LH current drive efficiency at high density. The ITPA IOS group coordinates this effort [1] and all experimental data are essential to validate the numerical codes in progress. Usually the broadening of the LH wave frequency spectrum is measured by a probe located in the plasma edge. For this study, the frequency spectrum of a reflected power signal from the LH antenna was used. In addition, the spectrum measurements are compared with the density fluctuations observed on RF probes located at the antenna mouth. Several plasma currents (0.6 to 1.4 MA) and densities up to 5.2 × 10{sup 19} m−3 have been realised on Tore Supra (TS) long pulses and with high injected RF power, up to 5.4 MW-30s. This allowed using a spectrum analyser to make several measurements during the plasma pulse. The side lobe amplitude, shifted by 20-30MHz with respect to the main peak, grows with increasing density. Furthermore, for an increase of plasma current at the same density, the spectra broaden and become asymmetric. Some parametric dependencies are shown in this paper.

  13. Favorable effect of aerobic exercise on arterial pressure and aortic pulse wave velocity during stress testing.

    Science.gov (United States)

    Milatz, Florian; Ketelhut, Sascha; Ketelhut, Sascha; Ketelhut, Reinhard G

    2015-07-01

    Increased central pulse wave velocity is a major risk factor for cardiovascular disease. The favorable influence of exercise on arterial stiffness (AS) and blood pressure (BP) has been reported exclusively at rest. The present study investigated the influence of a single bout of acute cycling on AS and BP during recovery and, moreover, during cold pressor stress testing. 32 healthy men (33.7 ± 8 years, BMI 24 ± 2.5 kg/m²) performed a 60 minute endurance exercise on a bicycle ergometer (45 % VO2max). Before and after exercise aortic pulse wave velocity (aPWV) as well as central and peripheral BP were measured non-invasively at rest and at the end of a 2 minute cold pressor test (CPT). Even after 60 minutes of recovery aPWV (- 0.22 ± 0.3 m / sec) was significantly reduced (p Exercise decreased peripheral (- 8 ± 7 mmHg) and central (- 7 ± 8 mmHg) systolic BP as well as peripheral (- 3 ± 5 mmHg) and central (- 4 ± 7 mmHg) diastolic BP (p exercise, there was a significant reduction in aPWV (- 0.19 ± 0.3 m / sec), peripheral (- 6 ± 10 mmHg) and central (- 5 ± 8 mmHg) systolic BP as well as peripheral (- 3 ± 6 mmHg) and central (- 3 ± 6 mmHg) diastolic BP during CPT after exercise (p exercise leads not only to decreased BP but even more reduces aPWV as a measure of AS even after 60 minutes of recovery. In particular, the investigation provides evidence that acute moderate-intensity exercise has a favorable effect on BP and aPWV during stress testing.

  14. 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

    (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......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......±20 vs. 152±21 mmHg, p=0.02) and pulse pressure (65±17 vs. 80±18 mmHg, p2.5 in HD and 12.3±3.1 m/s in HD+DM. The mean PWV difference HD vs. HD+DM was 3.1(1.9-4.3)m/s, p

  15. Study on ultrastructural changes in thyroid gland of rats exposed to pulsed electromagnetic wave

    International Nuclear Information System (INIS)

    Zhou Xiaoguang; Zeng Guiying; Ren Dongqing; Fang Henghu; Su Xiaoming; Huang Xiaofeng

    2006-01-01

    The work is to observe effects of PEMW (pulse electromagnetic wave) exposure on function and morphology of thyroid gland of rats. At different time points (24, 48, 96 and 192 h) after exposure to PEMW (E=115 kV m -1 , 12000 pulses), radioimmunoassay was performed to observe the levels of thyroid-stimulating hormone (TSH), thyroxine (T 4 ) and triiodo- thyronine (T 3 ) in sera of the male Sparague-Dawley rats. Optic microscopy and transmission electron microscopy (TEM) were used to observe structural changes of the thyroid gland at the time points. The T 3 , T 4 and TSH in sera increased significantly, reaching a peak at 24 h and decreasing gradually then. Although no obvious changes in the thyroid gland were observed under the optic microscope, some ultrastructural changes in the thyroid gland were found under the TEM. The ultrastructures were obviously changed at 12 h and aggravated until 48 h. In the experimented rats, dilatated endoplasmic reticulum gathered with lots of protein excretion, lipid droplet and heterochromatin gathered under the nucleus membranes were observed in follicular epithelial cells. These changes were palliated at 96 h but not recovered. PEMW can affect levels of hormones in sera and the hazard ultrastructural changes of thyroid gland. Endoplasmic reticulum is the main injured organelle. (authors)

  16. Investigation of a high frequency pulse tube cryocooler driven by a standing wave thermoacoustic engine

    International Nuclear Information System (INIS)

    Boroujerdi, A.A.; Ziabasharhagh, M.

    2014-01-01

    Highlights: • A nonlinear numerical model of a high frequency TADPTC has been developed. • The finite volume method has been used for discretization of governing equations. • The self-excitation process has been simulated very well. • The effects of APAT on the performance of the device have been investigated. • Lagrangian approach has been used to trace the thermodynamic cycle of gas parcels. - Abstract: In this work, a typical thermoacoustically driven pulse tube cooler as a no-moving part device has been investigated by a numerical method. A standing wave thermoacoustic engine as a prime mover in coupled with an inertance tube pulse tube cryocooler has been modeled. Nonlinear equations of unsteady one-dimensional compressible flow have been solved by the finite volume method. The model presents an important step towards the development of nonlinear simulation tools for the high amplitude thermoacoustic systems that are needed for practical use. The results of the computations show that the self-excited oscillations are well accompanied by the increasing of the pressure amplitude. The necessity of implementation of a nonlinear model to investigate such devices has been proven. The effect of APAT length as an amplifier coupler on the performance of the cooler has been investigated. Furthermore, by using Lagrangian approach, thermodynamic cycle of gas parcels has been attained

  17. The effect of the pulse repetition rate on the fast ionization wave discharge

    Science.gov (United States)

    Huang, Bang-Dou; Carbone, Emile; Takashima, Keisuke; Zhu, Xi-Ming; Czarnetzki, Uwe; Pu, Yi-Kang

    2018-06-01

    The effect of the pulse repetition rate (PRR) on the generation of high energy electrons in a fast ionization wave (FIW) discharge is investigated by both experiment and modelling. The FIW discharge is driven by nanosecond high voltage pulses and is generated in helium with a pressure of 30 mbar. The axial electric field (E z ), as the driven force of high energy electron generation, is strongly influenced by PRR. Both the measurement and the model show that, during the breakdown, the peak value of E z decreases with the PRR, while after the breakdown, the value of E z increases with the PRR. The electron energy distribution function (EEDF) is calculated with a model similar to Boeuf and Pitchford (1995 Phys. Rev. E 51 1376). It is found that, with a low value of PRR, the EEDF during the breakdown is strongly non-Maxwellian with an elevated high energy tail, while the EEDF after the breakdown is also non-Maxwellian but with a much depleted population of high energy electrons. However, with a high value of PRR, the EEDF is Maxwellian-like without much temporal variation both during and after the breakdown. With the calculated EEDF, the temporal evolution of the population of helium excited species given by the model is in good agreement with the measured optical emission, which also depends critically on the shape of the EEDF.

  18. Increasing accuracy of pulse transit time measurements by automated elimination of distorted photoplethysmography waves.

    Science.gov (United States)

    van Velzen, Marit H N; Loeve, Arjo J; Niehof, Sjoerd P; Mik, Egbert G

    2017-11-01

    Photoplethysmography (PPG) is a widely available non-invasive optical technique to visualize pressure pulse waves (PWs). Pulse transit time (PTT) is a physiological parameter that is often derived from calculations on ECG and PPG signals and is based on tightly defined characteristics of the PW shape. PPG signals are sensitive to artefacts. Coughing or movement of the subject can affect PW shapes that much that the PWs become unsuitable for further analysis. The aim of this study was to develop an algorithm that automatically and objectively eliminates unsuitable PWs. In order to develop a proper algorithm for eliminating unsuitable PWs, a literature study was conducted. Next, a '7Step PW-Filter' algorithm was developed that applies seven criteria to determine whether a PW matches the characteristics required to allow PTT calculation. To validate whether the '7Step PW-Filter' eliminates only and all unsuitable PWs, its elimination results were compared to the outcome of manual elimination of unsuitable PWs. The '7Step PW-Filter' had a sensitivity of 96.3% and a specificity of 99.3%. The overall accuracy of the '7Step PW-Filter' for detection of unsuitable PWs was 99.3%. Compared to manual elimination, using the '7Step PW-Filter' reduces PW elimination times from hours to minutes and helps to increase the validity, reliability and reproducibility of PTT data.

  19. First Electromagnetic Pulse Associated with a Gravitational-wave Event: Profile, Duration, and Delay

    Science.gov (United States)

    Lin, Da-Bin; Liu, Tong; Lin, Jie; Wang, Xiang-Gao; Gu, Wei-Min; Liang, En-Wei

    2018-04-01

    We study the first electromagnetic (EM) pulse after the gravitational-wave (GW) chirp signal, focusing on its profile and duration. It is found that the light curve, especially the steep decay (SD) phase, can be very different by adopting different viewing angles θ view of the jet shell. For an on-axis jet with a power-law radiation spectrum, the observed flux in the SD is proportional to {t}obs}-2-β with β being the spectral index and t obs being the observer time. Here, t obs = 0 is set at the time we observe the jet being ejected from the central engine. The SD may become steep by increasing θ view. We also study the bolometric luminosity L from a jet shell with a non-power-law radiation spectrum. For an on-axis jet, L ∝ t obs ‑3 is found in the SD. However, the SD is steeper than L\\propto {t}obs}-3 for radiation from an off-axis jet. The higher value of the θ view is, the steeper SD would be. Then, we suggest that the SD phase can be used to discriminate an off-axis jet from an on-axis jet. The reason for the above behaviors is discussed. In addition, we find that the duration of first EM pulse is close to its peak time, especially for θ view ∼ 20°. This result is consistent with that found in GW 170817/GRB 170817A. Thus, the jet corresponding to the prompt emission of GRB 170817A should be ejected immediately after the merger. Our results also reveal that the duration of the first EM pulse can provide information on the time to search for GWs.

  20. Pulsed-laser-activated impulse response encoder: Sensitive detection of surface elastic waves on biomimetic microsized gel spheres

    Science.gov (United States)

    Yasukuni, Ryohei; Fukushima, Ryosuke; Iino, Takanori; Hosokawa, Yoichiroh

    2017-11-01

    A femtosecond-laser-induced impulsive force was applied to microsized calcium alginate (CaAlg) gel spheres as an external force to excite elastic waves. To evaluate elasticity, atomic force microscopy (AFM) was applied to detect vibration propagation. The sphere size dependence of the vibration was well reproduced by finite element method (FEM) simulation for pressure waves and surface acoustic waves. The obtained results indicate that the pulsed-laser-activated impulse response encoder (PLAIRE) enables the sensitive detection of elasticities, not only on inside but also on the surface.

  1. Traveling waves in a spatially-distributed Wilson-Cowan model of cortex: From fronts to pulses

    Science.gov (United States)

    Harris, Jeremy D.; Ermentrout, Bard

    2018-04-01

    Wave propagation in excitable media has been studied in various biological, chemical, and physical systems. Waves are among the most common evoked and spontaneous organized activity seen in cortical networks. In this paper, we study traveling fronts and pulses in a spatially-extended version of the Wilson-Cowan equations, a neural firing rate model of sensory cortex having two population types: Excitatory and inhibitory. We are primarily interested in the case when the local or space-clamped dynamics has three fixed points: (1) a stable down state; (2) a saddle point with stable manifold that acts as a threshold for firing; (3) an up state having stability that depends on the time scale of the inhibition. In the case when the up state is stable, we look for wave fronts, which transition the media from a down to up state, and when the up state is unstable, we are interested in pulses, a transient increase in firing that returns to the down state. We explore the behavior of these waves as the time and space scales of the inhibitory population vary. Some interesting findings include bistability between a traveling front and pulse, fronts that join the down state to an oscillation or spatiotemporal pattern, and pulses which go through an oscillatory instability.

  2. Wearable sensor glove based on conducting fabric using electrodermal activity and pulse-wave sensors for e-health application.

    Science.gov (United States)

    Lee, Youngbum; Lee, Byungwoo; Lee, Myoungho

    2010-03-01

    Improvement of the quality and efficiency of health in medicine, both at home and the hospital, calls for improved sensors that might be included in a common carrier such as a wearable sensor device to measure various biosignals and provide healthcare services that use e-health technology. Designed to be user-friendly, smart clothes and gloves respond well to the end users for health monitoring. This study describes a wearable sensor glove that is equipped with an electrodermal activity (EDA) sensor, pulse-wave sensor, conducting fabric, and an embedded system. The EDA sensor utilizes the relationship between drowsiness and the EDA signal. The EDA sensors were made using a conducting fabric instead of silver chloride electrodes, as a more practical and practically wearable device. The pulse-wave sensor measurement system, which is widely applied in oriental medicinal practices, is also a strong element in e-health monitoring systems. The EDA and pulse-wave signal acquisition module was constructed by connecting the sensor to the glove via a conductive fabric. The signal acquisition module is then connected to a personal computer that displays the results of the EDA and pulse-wave signal processing analysis and gives accurate feedback to the user. This system is designed for a number of applications for the e-health services, including drowsiness detection and oriental medicine.

  3. Identifying coronary artery disease in asymptomatic middle-aged sportsmen : The additional value of pulse wave velocity

    NARCIS (Netherlands)

    Braber, Thijs L.; Prakken, Niek H J; Mosterd, Arend; Mali, Willem P Th M; Doevendans, Pieter A F M; Bots, Michiel L.; Velthuis, Birgitta K.

    2015-01-01

    Background: Cardiovascular screening may benefit middle-aged sportsmen, as coronary artery disease (CAD) is the main cause of exercise-related sudden cardiac death. Arterial stiffness, as measured by pulse wave velocity (PWV), may help identify sportsmen with subclinical CAD. We examined the

  4. Theory and experiment of Fourier-Bessel field calculation and tuning of a pulsed wave annular array

    DEFF Research Database (Denmark)

    Fox, Paul D.; Jiqi, Cheng; Jian-yu, Lu

    2003-01-01

    A one-dimensional (1D) Fourier-Bessel series method for computing and tuning (beamforming) the linear lossless field of flat pulsed wave annular arrays is developed and supported with both numerical simulation and experimental verification. The technique represents a new method for modeling and t...

  5. 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.

  6. Short-term effects of a standardized glucose load on region-specific aortic pulse wave velocity assessed by MRI

    NARCIS (Netherlands)

    Jonker, J.T.; Tjeerdema, N.; Hensen, L.C.; Lamb, H.J.; Romijn, J.A.; Smit, J.W.; Westenberg, J.J.; Roos, A. de

    2014-01-01

    PURPOSE: To assess the short-term effects of a standardized oral glucose load on regional aortic pulse wave velocity (PWV) using two-directional in-plane velocity encoded MRI. MATERIALS AND METHODS: A randomized, controlled intervention was performed in 16 male subjects (mean +/- standard deviation:

  7. The Effects of TM on Concurrent Heart Rate, Peripheral Blood Pulse Volume, and the Alpha Wave Frequency.

    Science.gov (United States)

    Lukas, Jerome S.

    Through observation of 26 subjects over a 3 month period, this research project measured the effects of transcendental meditation (TM) on concurrent heart rate, peripheral blood pulse volume, and the alpha wave frequency. The subjects were assigned randomly to three groups. One group practiced TM as prescribed by the International Meditation…

  8. Expert consensus document on the measurement of aortic stiffness in daily practice using carotid-femoral pulse wave velocity

    NARCIS (Netherlands)

    L.M. van Bortel (Luc); S. Laurent (Stephane); P. Boutouyrie (Pierre); P. Chowienczyk (Phil); J.K. Cruickshank (Kennedy); T.L.M. de Backer (Tine); J. Filipovsky (Jan); S. Huybrechts (Sofie); F.U.S. Mattace Raso (Francesco); A.D. Protogerou (Athanase); G. Schillaci (Giuseppe); P. Segers (Patrick); S. Vermeersch (Steve); T. Weber (Thomas)

    2012-01-01

    textabstractStiffness of elastic arteries like the aorta predicts cardiovascular risk. By directly reflecting arterial stiffness, having the best predictive value for cardiovascular outcome and the ease of its measurement, carotid-femoral pulse wave velocity is now considered the gold standard for

  9. Enhanced shock wave generation via pre-breakdown acceleration using water electrolysis in negative streamer pulsed spark discharges

    Science.gov (United States)

    Lee, Kern; Chung, Kyoung-Jae; Hwang, Y. S.

    2018-03-01

    This paper presents a method for enhancement of shock waves generated from underwater pulsed spark discharges with negative (anode-directed) subsonic streamers, for which the pre-breakdown process is accelerated by preconditioning a gap with water electrolysis. Hydrogen microbubbles are produced at the cathode by the electrolysis and move towards the anode during the preconditioning phase. The numbers and spatial distributions of the microbubbles vary with the amplitude and duration of each preconditioning pulse. Under our experimental conditions, the optimum pulse duration is determined to be ˜250 ms at a pulse voltage of 400 V, where the buoyancy force overwhelms the electric force and causes the microbubbles to be swept out from the water gap. When a high-voltage pulse is applied to the gap just after the preconditioning pulse, the pre-breakdown process is significantly accelerated in the presence of the microbubbles. At the optimum preconditioning pulse duration, the average breakdown delay is reduced by 87% and, more importantly, the energy consumed during the pre-breakdown period decreases by 83%. This reduced energy consumption during the pre-breakdown period, when combined with the morphological advantages of negative streamers, such as thicker and longer stalks, leads to a significant improvement in the measured peak pressure (˜40%) generated by the underwater pulsed spark discharge. This acceleration of pre-breakdown using electrolysis overcomes the biggest drawback of negative subsonic discharges, which is slow vapor bubble formation due to screening effects, and thus enhances the efficiency of the shock wave generation process using pulsed spark discharges in water.

  10. 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.

  11. A comparison between the pathophysiology of multiple sclerosis and normal pressure hydrocephalus: is pulse wave encephalopathy a component of MS?

    Science.gov (United States)

    Bateman, Grant A; Lechner-Scott, Jeannette; Lea, Rodney A

    2016-09-22

    It has been suggested there is a chronic neurodegenerative disorder, underlying the pathophysiology of multiple sclerosis (MS), which is distinct from the more obvious immune-mediated attack on the white matter. Limited data exists indicating there is an alteration in pulse wave propagation within the craniospinal cavity in MS, similar to the findings in normal pressure hydrocephalus (NPH). It is hypothesized MS may harbor pulse wave encephalopathy. The purpose of this study is to compare blood flow and pulse wave measurements in MS patients with a cohort of NPH patients and control subjects, to test this hypothesis. Twenty patients with MS underwent magnetic resonance (MR) flow quantification techniques. Mean blood flow and stroke volume were measured in the arterial inflow and venous out flow from the sagittal (SSS) and straight sinus (ST). The arteriovenous delay (AVD) was defined. The results were compared with both age-matched controls and NPH patients. In MS there was a 35 % reduction in arteriovenous delay and a 5 % reduction in the percentage of the arterial inflow returning via the sagittal sinus compared to age matched controls. There was an alteration in pulse wave propagation, with a 26 % increase in arterial stroke volume but 30 % reduction in SSS and ST stroke volume. The AVD and blood flow changes were in the same direction to those of NPH patients. There are blood flow and pulsation propagation changes in MS patients which are similar to those of NPH patients. The findings would be consistent with an underlying pulse wave encephalopathy component in MS.

  12. P-wave pulse analysis to retrieve source and propagation effects in the case of Vrancea earthquakes

    International Nuclear Information System (INIS)

    Popescu, E.; Popa, M.; Placinta, A.; Grecu, B.; Radulian, M.

    2004-01-01

    Seismic source parameters and attenuation structure properties are obtained from the first P-wave pulse analysis and empirical Green's function deconvolution. The P pulse characteristics are combined effects of source and path properties. To reproduce the real source and structure parameters it is crucial to apply a method able to distinguish between the different factors affecting the observed seismograms. For example the empirical Green's function deconvolution method (Hartzell, 1978) allows the retrieval of the apparent source time function or source spectrum corrected for path, site and instrumental effects. The apparent source duration is given by the width of the deconvoluted source pulse and is directly related to the source dimension. Once the source time function established, next we can extract the parameters related to path effects. The difference between the pulse recorded at a given station and the source pulse obtained by deconvolution is a measure of the attenuation along the path from focus to the station. On the other hand, the pulse width variations with azimuth depend critically on the fault plane orientation and source directivity. In favourable circumstances (high signal/noise ratio, high resolution and station coverage), the method of analysis proposed in this paper allows the constraint of the rupture plane among the two nodal planes characterizing the fault plane solution, even for small events. P-wave pulse analysis was applied for 25 Vrancea earthquakes recorded between 1999 and 2003 by the Romanian local network to determine source parameters and attenuation properties. Our results outline high-stress drop seismic energy release with relatively simple rupture process for the considered events and strong lateral variation of attenuation of seismic waves across Carpathians Arc. (authors)

  13. Supervised learning methods for pathological arterial pulse wave differentiation: A SVM and neural networks approach.

    Science.gov (United States)

    Paiva, Joana S; Cardoso, João; Pereira, Tânia

    2018-01-01

    The main goal of this study was to develop an automatic method based on supervised learning methods, able to distinguish healthy from pathologic arterial pulse wave (APW), and those two from noisy waveforms (non-relevant segments of the signal), from the data acquired during a clinical examination with a novel optical system. The APW dataset analysed was composed by signals acquired in a clinical environment from a total of 213 subjects, including healthy volunteers and non-healthy patients. The signals were parameterised by means of 39pulse features: morphologic, time domain statistics, cross-correlation features, wavelet features. Multiclass Support Vector Machine Recursive Feature Elimination (SVM RFE) method was used to select the most relevant features. A comparative study was performed in order to evaluate the performance of the two classifiers: Support Vector Machine (SVM) and Artificial Neural Network (ANN). SVM achieved a statistically significant better performance for this problem with an average accuracy of 0.9917±0.0024 and a F-Measure of 0.9925±0.0019, in comparison with ANN, which reached the values of 0.9847±0.0032 and 0.9852±0.0031 for Accuracy and F-Measure, respectively. A significant difference was observed between the performances obtained with SVM classifier using a different number of features from the original set available. The comparison between SVM and NN allowed reassert the higher performance of SVM. The results obtained in this study showed the potential of the proposed method to differentiate those three important signal outcomes (healthy, pathologic and noise) and to reduce bias associated with clinical diagnosis of cardiovascular disease using APW. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Development of Coronary Pulse Wave Velocity: New Pathophysiological Insight Into Coronary Artery Disease.

    Science.gov (United States)

    Harbaoui, Brahim; Courand, Pierre-Yves; Cividjian, Andrei; Lantelme, Pierre

    2017-02-02

    Although aortic stiffness assessed by pulse wave velocity (PWV) is a strong predictor of coronary artery disease, the significance of local coronary stiffness has never been tackled. The first objective of this study was to describe a method of measuring coronary PWV (CoPWV) invasively and to describe its determinants. The second objective was to assess both CoPWV and aortic PWV in patients presenting with acute coronary syndromes or stable coronary artery disease. In 53 patients, CoPWV was measured from the delay in pressure wave and distance traveled as a pressure wire was withdrawn from the distal to the proximal coronary segment. Similarly, aortic PWV was measured invasively when the wire was pulled across the ascending aorta; carotid-femoral PWV was also measured noninvasively using the SphygmoCor system (AtCor Medical). Mean CoPWV was 10.3±6.1 m/s. Determinants of increased CoPWV were fractional flow reserve, diastolic blood pressure, and previous stent implantation in the recorded artery. CoPWV was lower in patients with acute coronary syndromes versus stable coronary artery disease (7.6±3 versus 11.5±6.4 m/s; P=0.02), and this persisted after adjustment for confounders. In contrast, aortic stiffness, assessed by aortic and carotid-femoral PWV, did not differ significantly. CoPWV seems associated with acute coronary events more closely than aortic PWV. High coronary compliance, whether per se or because it leads to a distal shift in compliance mismatch, may expose vulnerable plaques to high cyclic stretch. CoPWV is a new tool to assess local compliance at the coronary level; it paves the way for a new field of research. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

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

    International Nuclear Information System (INIS)

    Chen Baozhen; Huang Zuqia

    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.

  16. Effects of Obesity and Hypertension on Pulse Wave Velocity in Children.

    Science.gov (United States)

    Kulsum-Mecci, Nazia; Goss, Charles; Kozel, Beth A; Garbutt, Jane M; Schechtman, Kenneth B; Dharnidharka, Vikas R

    2017-03-01

    Pulse wave velocity (PWV) is a biomarker of arterial stiffness. Findings from prior studies are conflicting regarding the impact of obesity on PWV in children. The authors measured carotid-femoral PWV in 159 children aged 4 to 18 years, of whom 95 were healthy, 25 were obese, 15 had hypertension (HTN), and 24 were both obese and hypertensive. Mean PWV increased with age but did not differ by race or sex. In adjusted analyses in children 10 years and older (n=102), PWV was significantly higher in children with hypertension (PWV±standard deviation, 4.9±0.7 m/s), obesity (5.0±0.9 m/s), and combined obesity-hypertension (5.2±0.6 m/s) vs healthy children (4.3±0.7 m/s) (each group, Pobesity and HTN both significantly and independently increased PWV, while African American children did not have a higher PWV than Caucasian children. ©2016 Wiley Periodicals, Inc.

  17. Pulse propagation dynamics in the presence of a continuous-wave field

    International Nuclear Information System (INIS)

    Dimitrijević, Jelena; Arsenović, Dušan; Jelenković, Branislav M

    2013-01-01

    We present theoretical results for the propagation dynamics of an electromagnetic field pulse through rubidium vapor, while another field, a continuous-wave electromagnetic field, is present. The frequencies of both electromagnetic fields are resonant with the transition between the ground and excited state hyperfine levels of Rb, F g  → F e  = F g  ± 1. Detuning from resonance is done by the magnetic field oriented along the light propagation direction (Hanle configuration). When both the electromagnetic fields are simultaneously interacting with Rb atoms, either electromagnetically induced transparency or absorption is induced. Propagation dynamics was obtained solving the set of Maxwell–Bloch equations for the interacting atoms with two electromagnetic fields. Motivated by recent results (Brazhnikov et al 2011 Eur. Phys. J. D 63 315–25; Brazhnikov et al 2010 JETP Lett. 91 625–9; Kou et al 2011 Phys. Rev. A 84 063807), we have analyzed the influence of experimental parameters, laser polarization, and mutual phases between lasers, which can lead to optical switching, i.e. the transformation from electromagnetically induced absorption to transparency and vice versa. (paper)

  18. 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%. © 2015 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons Ltd.

  19. The effective reflection of a pulse sequence from a four-wave mirror with thermal nonlinearity under parametric feedback

    Science.gov (United States)

    Barashkov, M. S.; Bel'Diugin, I. M.; Zolotarev, M. V.; Kruzhilin, Iu. I.; Krymskii, M. I.

    1989-04-01

    A four-wave mirror with thermal nonlinearity has been experimentally realized with the interaction of corunning waves under parametric feedback with a nonreciprocal element. The effective reflection of a sequence of pulses with duration of about 300 ns from a neodymium-glass laser with maximal reflection coefficients greater than 30 has been demonstrated. The quality of the radiation reflected from the mirror is studied. A significant reduction in the steady-state lasing threshold has been shown with thermal nonlinearity at small angles of the interacting beam convergence, compared to the case of counterrunning convergence.

  20. Numerical modeling of the pulse wave propagation in large blood vessels based on liquid and wall interaction

    International Nuclear Information System (INIS)

    Rup, K; Dróżdż, A

    2014-01-01

    The purpose of this article is to develop a non-linear, one-dimensional model of pulse wave propagation in the arterial cardiovascular system. The model includes partial differential equations resulting from the balance of mass and momentum for the fluid-filled area and the balance equation for the area of the wall and vessels. The considered mathematical model of pulse wave propagation in the thoracic aorta section takes into account the viscous dissipation of fluid energy, realistic values of parameters describing the physicochemical properties of blood and vessel wall. Boundary and initial conditions contain the appropriate information obtained from in vivo measurements. As a result of the numerical solution of the mass and momentum balance equations for the blood and the equilibrium equation for the arterial wall area, time- dependent deformation, respective velocity profiles and blood pressure were determined.

  1. Determination of Testicular Blood Flow in Camelids Using Vascular Casting and Color Pulsed-Wave Doppler Ultrasonography

    OpenAIRE

    Kutzler, Michelle; Tyson, Reid; Grimes, Monica; Timm, Karen

    2011-01-01

    We describe the vasculature of the camelid testis using plastic casting. We also use color pulsed-wave Doppler ultrasonography to measure testicular blood flow and compare the differences between testicular blood flow in fertile and infertile camelids. The testicular artery originates from the ventral surface of the aorta, gives rise to an epididymal branch, and becomes very tortuous as it approaches the testis. Within the supratesticular arteries, peak systolic velocity (PSV) was higher in f...

  2. Correlation of pulse wave velocity with left ventricular mass in patients with hypertension once blood pressure has been normalized

    Directory of Open Access Journals (Sweden)

    Siu H. Chan

    2012-02-01

    Full Text Available Vascular stiffness has been proposed as a simple method to assess arterial loading conditions of the heart which induce left ventricular hypertrophy (LVH. There is some controversy as to whether the relationship of vascular stiffness to LVH is independent of blood pressure, and which measurement of arterial stiffness, augmentation index (AI or pulse wave velocity (PWV is best. Carotid pulse wave contor and pulse wave velocity of patients (n=20 with hypertension whose blood pressure (BP was under control (<140/90 mmHg with antihypertensive drug treatment medications, and without valvular heart disease, were measured. Left ventricular mass, calculated from 2D echocardiogram, was adjusted for body size using two different methods: body surface area and height. There was a significant (P<0.05 linear correlation between LV mass index and pulse wave velocity. This was not explained by BP level or lower LV mass in women, as there was no significant difference in PWV according to gender (1140.1+67.8 vs 1110.6+57.7 cm/s. In contrast to PWV, there was no significant correlation between LV mass and AI. In summary, these data suggest that aortic vascular stiffness is an indicator of LV mass even when blood pressure is controlled to less than 140/90 mmHg in hypertensive patients. The data further suggest that PWV is a better proxy or surrogate marker for LV mass than AI and the measurement of PWV may be useful as a rapid and less expensive assessment of the presence of LVH in this patient population.

  3. High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

    OpenAIRE

    Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

    2015-01-01

    Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 ...

  4. Energy of a shock wave generated in different metals under irradiation by a high-power laser pulse

    International Nuclear Information System (INIS)

    Gus'kov, S. Yu.; Kasperczuk, A.; Pisarczyk, T.; Borodziuk, S.; Ullschmied, J.; Krousky, E.; Masek, K.; Pfeifer, M.; Skala, J.; Pisarczyk, P.

    2007-01-01

    The energies of a shock wave generated in different metals under irradiation by a high-power laser beam were determined experimentally. The experiments were performed with the use of targets prepared from a number of metals, such as aluminum, copper, silver and lead (which belong to different periods of the periodic table) under irradiation by pulses of the first and third harmonics of the PALS iodine laser at a radiation intensity of approximately 10 14 W/cm 2 . It was found that, for heavy metals, like for light solid materials, the fraction of laser radiation energy converted into the energy of a shock wave under irradiation by a laser pulse of the third harmonic considerably (by a factor of 2-3) exceeds the fraction of laser radiation energy converted under irradiation by a laser pulse of the first harmonic. The influence of radiation processes on the efficiency of conversion of the laser energy into the energy of the shock wave was analyzed

  5. Non-invasive aortic systolic pressure and pulse wave velocity estimation in a primary care setting: An in silico study.

    Science.gov (United States)

    Guala, Andrea; Camporeale, Carlo; Ridolfi, Luca; Mesin, Luca

    2017-04-01

    Everyday clinical cardiovascular evaluation is still largely based on brachial systolic and diastolic pressures. However, several clinical studies have demonstrated the higher diagnostic capacities of the aortic pressure, as well as the need to assess the aortic mechanical properties (e.g., by measuring the aortic pulse wave velocity). In order to fill this gap, we propose to exploit a set of easy-to-obtain physical characteristics to estimate the aortic pressure and pulse wave velocity. To this aim, a large population of virtual subjects is created by a validated mathematical model of the cardiovascular system. Quadratic regressive models are then fitted and statistically selected in order to obtain reliable estimations of the aortic pressure and pulse wave velocity starting from the knowledge of the subject age, height, weight, brachial pressure, photoplethysmographic measures and either electrocardiogram or phonocardiogram. The results are very encouraging and foster clinical studies aiming to apply a similar technique to a real population. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  6. Investigation on the generation characteristic of pressure pulse wave signal during the measurement-while-drilling process

    Science.gov (United States)

    Changqing, Zhao; Kai, Liu; Tong, Zhao; Takei, Masahiro; Weian, Ren

    2014-04-01

    The mud-pulse logging instrument is an advanced measurement-while-drilling (MWD) tool and widely used by the industry in the world. In order to improve the signal transmission rate, ensure the accurate transmission of information and address the issue of the weak signal on the ground of oil and gas wells, the signal generator should send out the strong mud-pulse signals with the maximum amplitude. With the rotary valve pulse generator as the study object, the three-dimensional Reynolds NS equations and standard k - ɛ turbulent model were used as a mathematical model. The speed and pressure coupling calculation was done by simple algorithms to get the amplitudes of different rates of flow and axial clearances. Tests were done to verify the characteristics of the pressure signals. The pressure signal was captured by the standpiece pressure monitoring system. The study showed that the axial clearances grew bigger as the pressure wave amplitude value decreased and caused the weakening of the pulse signal. As the rate of flow got larger, the pressure wave amplitude would increase and the signal would be enhanced.

  7. Carotid-femoral pulse wave velocity in a healthy adult sample: The ELSA-Brasil study.

    Science.gov (United States)

    Baldo, Marcelo Perim; Cunha, Roberto S; Molina, Maria Del Carmen B; Chór, Dora; Griep, Rosane H; Duncan, Bruce B; Schmidt, Maria Inês; Ribeiro, Antonio L P; Barreto, Sandhi M; Lotufo, Paulo A; Bensenor, Isabela M; Pereira, Alexandre C; Mill, José Geraldo

    2018-01-15

    Aging declines essential physiological functions, and the vascular system is strongly affected by artery stiffening. We intended to define the age- and sex-specific reference values for carotid-to-femoral pulse wave velocity (cf-PWV) in a sample free of major risk factors. The ELSA-Brasil study enrolled 15,105 participants aged 35-74years. The healthy sample was achieved by excluding diabetics, those over the optimal and normal blood pressure levels, body mass index ≤18.5 or ≥25kg/m 2 , current and former smokers, and those with self-report of previous cardiovascular disease. After exclusions, the sample consisted of 2158 healthy adults (1412 women). Although cf-PWV predictors were similar between sex (age, mean arterial pressure (MAP) and heart rate), cf-PWV was higher in men (8.74±1.15 vs. 8.31±1.13m/s; adjusted for age and MAP, PELSA-Brasil population (n=15,105) increased by twice the age-related slope of cf-PWV growth, regardless of sex (0.0919±0.182 vs. 0.0504±0.153m/s per year for men, 0.0960±0.173 vs. 0.0606±0.139m/s per year for women). cf-PWV is different between men and women and even in an optimal and normal range of MAP and free of other classical risk factors for arterial stiffness, reference values for cf-PWV should take into account MAP levels. Also, the presence of major risk factors in the general population doubles the age-related rise in cf-PWV. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Genetic influence on the relation between exhaled nitric oxide and pulse wave reflection.

    Science.gov (United States)

    Tarnoki, David Laszlo; Tarnoki, Adam Domonkos; Medda, Emanuela; Littvay, Levente; Lazar, Zsofia; Toccaceli, Virgilia; Fagnani, Corrado; Stazi, Maria Antonietta; Nisticó, Lorenza; Brescianini, Sonia; Penna, Luana; Lucatelli, Pierleone; Boatta, Emanuele; Zini, Chiara; Fanelli, Fabrizio; Baracchini, Claudio; Meneghetti, Giorgio; Koller, Akos; Osztovits, Janos; Jermendy, Gyorgy; Preda, Istvan; Kiss, Robert Gabor; Karlinger, Kinga; Lannert, Agnes; Horvath, Tamas; Schillaci, Giuseppe; Molnar, Andrea Agnes; Garami, Zsolt; Berczi, Viktor; Horvath, Ildiko

    2013-06-01

    Nitric oxide has an important role in the development of the structure and function of the airways and vessel walls. Fractional exhaled nitric oxide (FE(NO)) is inversely related to the markers and risk factors of atherosclerosis. We aimed to estimate the relative contribution of genes and shared and non-shared environmental influences to variations and covariation of FE(NO) levels and the marker of elasticity function of arteries. Adult Caucasian twin pairs (n = 117) were recruited in Hungary, Italy and in the United States (83 monozygotic and 34 dizygotic pairs; age: 48 ± 16 SD years). FE(NO) was measured by an electrochemical sensor-based device. Pulse wave reflection (aortic augmentation index, Aix(ao)) was determined by an oscillometric method (Arteriograph). A bivariate Cholesky decomposition model was applied to investigate whether the heritabilities of FE(NO) and Aix(ao) were linked. Genetic effects accounted for 58% (95% confidence interval (CI): 42%, 71%) of the variation in FE(NO) with the remaining 42% (95%CI: 29%, 58%) due to non-shared environmental influences. A modest negative correlation was observed between FE(NO) and Aix(ao) (r = -0.17; 95%CI:-0.32,-0.02). FE(NO) showed a significant negative genetic correlation with Aix(ao) (r(g) = -0.25; 95%CI:-0.46,-0.02). Thus in humans, variations in FE(NO) are explained both by genetic and non-shared environmental effects. Covariance between FE(NO) and Aix(ao) is explained entirely by shared genetic factors. This is consistent with an overlap among the sets of genes involved in the expression of these phenotypes and provides a basis for further genetic studies on cardiovascular and respiratory diseases.

  9. Commissioning of the long-pulse fast wave current drive antennas for DIII-D

    International Nuclear Information System (INIS)

    Baity, F.W.; Barber, G.C.; Goulding, R.H.; Hoffman, D.J.; DeGrassie, J.S.; Pinsker, R.I.; Petty, C.C.; Cary, W.

    1995-01-01

    Two new four-element fast wave current drive antennas have been installed on DIII-D. These antennas are designed for 10-s pulses at 2 MW each in the frequency range of 30 to 120 MHz. Each element comprises two poloidal segments fed in parallel in order to optimize plasma coupling at the upper end of the frequency range. The antennas are mounted on opposite sides of the vacuum vessel, in ports designated 0 degrees and 180 degrees after their toroidal angle. Each antenna array is fed by a single transmitter. The power is first split two ways by means of a 3-dB hybrid coupler, then each of these lines feeds a resonant loop connecting a pair of array elements. The power transfer during asymmetric phasing is shunted between resonant loops by a decoupler. The resonant loops are fitted with line stretchers so that multiple frequencies of operation are possible without reconfiguring the transmission line. Commissioning of these antennas has been underway since June 1994. Several deficiencies in the transmission line system were uncovered during initial vacuum conditioning, including problems with the transmission line insulators and with the drive rods for the variable elements. The former was solved by replacing the original alumina insulators, and the latter has been avoided during operation to date by positioning the tuners to avoid high voltage appearing on the drive rods. A modified design for the drive rods will be implemented before RF operations resume operation June 1995. New transmitters were procured from ABB for the new antennas and were installed in parallel with the antenna installation. During initial vacuum conditioning of the antenna in the 180 degree port a fast digital oscilloscope was used to try to pinpoint the location of arcing by a time-of-flight technique and to develop an understanding of the typical arc signature in the system

  10. The association between pulse wave velocity and peripheral neuropathy in patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Tentolouris, Anastasios; Eleftheriadou, Ioanna; Grigoropoulou, Pinelopi; Kokkinos, Alexander; Siasos, Gerasimos; Ntanasis-Stathopoulos, Ioannis; Tentolouris, Nikolaos

    2017-11-01

    Diabetic peripheral neuropathy (DPN) is the most common diabetic complication, affecting up to half of the patients with type 2 diabetes mellitus (T2DM). Increased aortic stiffness, measured with the carotid-femoral pulse wave velocity (PWV), has been associated with incidence of cardiovascular disease independently of traditional risk factors. Previous data showed associations between risk factors for macroangiopathy and DPN in diabetes. However, the association between PWV and DPN is not well known. In this study we examined the association between PWV and presence as well as severity of DPN in subjects with T2DM. A total of 381 patients with T2DM were recruited. Participants were classified as having DPN and not having DPN. PWV was measured at the carotid-femoral segment with a non-invasive method using applanation tonometry. DPN was assessed by determination of the Neuropathy Symptom Score (NSS) and the Neuropathy Disability Score (NDS). A hundred and seven participants (28.1%) had DPN. Patients with DPN were significantly more often male and older, had longer diabetes duration, higher height, larger waist circumference, higher systolic arterial blood pressure (SBP) and higher PWV (all Pperipheral arterial disease. Multivariate logistic regression analysis, after adjustment for age, gender, waist circumference, SBP, nephropathy and use of b-blockers, demonstrated that the odds [OR (95% confidence intervals)] of peripheral neuropathy were associated significantly and independently only with diabetes duration [1.044 (1.009-1.081), P=0.013], height [1.075 (1.041-1.110), Pperipheral arterial disease [4.658 (2.264-9.584), Pperipheral arterial disease (beta=0.374, P<0.001). Increased PWV is associated strongly and independently not only with the presence but also with the severity of DPN in patients with T2DM, irrespective of known risk factors. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Pulse wave velocity and cardiac autonomic function in type 2 diabetes mellitus.

    Science.gov (United States)

    Chorepsima, Stamatina; Eleftheriadou, Ioanna; Tentolouris, Anastasios; Moyssakis, Ioannis; Protogerou, Athanasios; Kokkinos, Alexandros; Sfikakis, Petros P; Tentolouris, Nikolaos

    2017-05-19

    Increased carotid-femoral pulse wave velocity (PWV) has been associated with incident cardiovascular disease, independently of traditional risk factors. Cardiac autonomic dysfunction is a common complication of diabetes and has been associated with reduced aortic distensibility. However, the association of cardiac autonomic dysfunction with PWV is not known. In this study we examined the association between cardiac autonomic function and PWV in subjects with type 2 diabetes mellitus. A total of 290 patients with type 2 diabetes were examined. PWV was measured at the carotid-femoral segment with applanation tonometry. Central mean arterial blood pressure (MBP) was determined by the same apparatus. Participants were classified as having normal (n = 193) or abnormal (n = 97) PWV values using age-corrected values. Cardiac autonomic nervous system activity was determined by measurement of parameters of heart rate variability (HRV). Subjects with abnormal PWV were older, had higher arterial blood pressure and higher heart rate than those with normal PWV. Most of the values of HRV were significantly lower in subjects with abnormal than in those with normal PWV. Multivariate analysis, after controlling for various confounding factors, demonstrated that abnormal PWV was associated independently only with peripheral MBP [odds ratio (OR) 1.049, 95% confidence intervals (CI) 1.015-1.085, P = 0.005], central MBP (OR 1.052, 95% CI 1.016-1.088, P = 0.004), log total power (OR 0.490, 95% CI 0.258-0.932, P = 0.030) and log high frequency power (OR 0.546, 95% CI 0.301-0.991, P = 0.047). In subjects with type 2 diabetes, arterial blood pressure and impaired cardiac autonomic function is associated independently with abnormal PWV.

  12. Measuring and engineering the atomic mass density wave of a Gaussian mass-polariton pulse in optical fibers

    Science.gov (United States)

    Partanen, Mikko; Tulkki, Jukka

    2018-02-01

    Conventional theories of electromagnetic waves in a medium assume that only the energy of the field propagates inside the medium. Consequently, they neglect the transport of mass density by the medium atoms. We have recently presented foundations of a covariant theory of light propagation in a nondispersive medium by considering a light wave simultaneously with the dynamics of the medium atoms driven by optoelastic forces [Phys. Rev. A 95, 063850 (2017)]. In particular, we have shown that the mass is transferred by an atomic mass density wave (MDW), which gives rise to mass-polariton (MP) quasiparticles, i.e., covariant coupled states of the field and matter having a nonzero rest mass. Another key observation of the mass-polariton theory of light is that, in common semiconductors, most of the momentum of light is transferred by moving atoms, e.g., 92% in the case of silicon. In this work, we generalize the MP theory of light for dispersive media and consider experimental measurement of the mass transferred by the MDW atoms when an intense light pulse propagates in a silicon fiber. In particular, we consider optimal intensity and time dependence of a Gaussian pulse and account for the breakdown threshold irradiance of the material. The optical shock wave property of the MDW, which propagates with the velocity of light instead of the velocity of sound, prompts for engineering of novel device concepts like very high frequency mechanical oscillators not limited by the acoustic cutoff frequency.

  13. Switching waves dynamics in optical bistable cavity-free system at femtosecond laser pulse propagation in semiconductor under light diffraction

    Science.gov (United States)

    Trofimov, Vyacheslav A.; Egorenkov, Vladimir A.; Loginova, Maria M.

    2018-02-01

    We consider a propagation of laser pulse in a semiconductor under the conditions of an occurrence of optical bistability, which appears due to a nonlinear absorption of the semiconductor. As a result, the domains of high concentration of free charged particles (electrons and ionized donors) occur if an intensity of the incident optical pulse is greater than certain intensity. As it is well-known, that an optical beam must undergo a diffraction on (or reflection from) the domains boundaries. Usually, the beam diffraction along a coordinate of the optical pulse propagation does not take into account by using the slowly varying envelope approximation for the laser pulse interaction with optical bistable element. Therefore, a reflection of the beam from the domains with abrupt boundary does not take into account under computer simulation of the laser pulse propagation. However, the optical beams, reflected from nonhomogeneities caused by the domains of high concentration of free-charged particles, can essentially influence on a formation of switching waves in a semiconductor. We illustrate this statement by computer simulation results provided on the base of nonlinear Schrödinger equation and a set of PDEs, which describe an evolution of the semiconductor characteristics (concentrations of free-charged particles and potential of an electric field strength), and taking into account the longitudinal and transverse diffraction effects.

  14. The energy and temporal characteristics of orthogonal polarized waves generated by a transversely-excited pulsed CO/sub 2/ laser

    Energy Technology Data Exchange (ETDEWEB)

    Bertel, I.M.; Churakov, V.V.; Petukhov, V.O.; Prokopov, A.P.; Trushin, S.A.; Voitovich, A.P.

    1980-01-01

    The competition of orthogonally-polarized waves with various differences in the wave Q-factors and active medium pressures is studied. The possibility of controlling the parameters of a pulsed CO/sub 2/ laser by changing the value of the amplitude anisotropy of the cavity is demonstrated. The duration of the emission pulse for one of two orthogonal polarizations was reduced by virtually 50%.

  15. Effects of Acupuncture Stimulation on the Radial artery’s Pressure Pulse Wave in Healthy Young Participants: Protocol for a prospective, single-Arm, Exploratory, Clinical Study

    Directory of Open Access Journals (Sweden)

    Jae-Young Shin

    2016-09-01

    Full Text Available Introduction: This study aims to investigate the effects of acupuncture stimulation on the radial artery’s pressure pulse wave, along with various hemodynamic parameters, and to explore the possible underlying mechanism of pulse diagnosis in healthy participants in their twenties. Methods and analysis: This study is a prospective, si

  16. Effects of a longitudinal magnetic field on current pulses and fast ionization-wave structure

    International Nuclear Information System (INIS)

    Asinovskii, E.I.; Lagar'kov, A.N.; Markovets, V.V.; Rutkevich, I.M.; Ul'yanov, A.M.; Filyugin, I.V.

    1988-01-01

    A longitudinal magnetic field affects the fast ionization-wave structure in a discharge tube surrounded by a metal screen. The field does not alter the wave speed, but the current amplitude is increased. This is explained from a theory for fast-wave propagation in a cylindrical guide containing an axial field. Numerical solutions have been obtained for the stationary nonlinear waves, which are compared with measurements. A theoretical study has been made on the ionization-wave features for large values of the Hall parameter

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

    Indian Academy of Sciences (India)

    2014-01-05

    Jan 5, 2014 ... 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 ... Solid State Laser Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013, India ...

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

    International Nuclear Information System (INIS)

    Pavicic, Ivan; Trosic, Ivancica

    2008-01-01

    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 1x10 4 cells/mL. Cells were maintained in the standard laboratory conditions, which are humidified atmosphere, 37 C degrees, and 5% CO 2 . Cell

  19. Travelling Wave Pulse Coupled Oscillator (TWPCO) Using a Self-Organizing Scheme for Energy-Efficient Wireless Sensor Networks.

    Science.gov (United States)

    Al-Mekhlafi, Zeyad Ghaleb; Hanapi, Zurina Mohd; Othman, Mohamed; Zukarnain, Zuriati Ahmad

    2017-01-01

    Recently, Pulse Coupled Oscillator (PCO)-based travelling waves have attracted substantial attention by researchers in wireless sensor network (WSN) synchronization. Because WSNs are generally artificial occurrences that mimic natural phenomena, the PCO utilizes firefly synchronization of attracting mating partners for modelling the WSN. However, given that sensor nodes are unable to receive messages while transmitting data packets (due to deafness), the PCO model may not be efficient for sensor network modelling. To overcome this limitation, this paper proposed a new scheme called the Travelling Wave Pulse Coupled Oscillator (TWPCO). For this, the study used a self-organizing scheme for energy-efficient WSNs that adopted travelling wave biologically inspired network systems based on phase locking of the PCO model to counteract deafness. From the simulation, it was found that the proposed TWPCO scheme attained a steady state after a number of cycles. It also showed superior performance compared to other mechanisms, with a reduction in the total energy consumption of 25%. The results showed that the performance improved by 13% in terms of data gathering. Based on the results, the proposed scheme avoids the deafness that occurs in the transmit state in WSNs and increases the data collection throughout the transmission states in WSNs.

  20. Travelling Wave Pulse Coupled Oscillator (TWPCO) Using a Self-Organizing Scheme for Energy-Efficient Wireless Sensor Networks

    Science.gov (United States)

    Hanapi, Zurina Mohd; Othman, Mohamed; Zukarnain, Zuriati Ahmad

    2017-01-01

    Recently, Pulse Coupled Oscillator (PCO)-based travelling waves have attracted substantial attention by researchers in wireless sensor network (WSN) synchronization. Because WSNs are generally artificial occurrences that mimic natural phenomena, the PCO utilizes firefly synchronization of attracting mating partners for modelling the WSN. However, given that sensor nodes are unable to receive messages while transmitting data packets (due to deafness), the PCO model may not be efficient for sensor network modelling. To overcome this limitation, this paper proposed a new scheme called the Travelling Wave Pulse Coupled Oscillator (TWPCO). For this, the study used a self-organizing scheme for energy-efficient WSNs that adopted travelling wave biologically inspired network systems based on phase locking of the PCO model to counteract deafness. From the simulation, it was found that the proposed TWPCO scheme attained a steady state after a number of cycles. It also showed superior performance compared to other mechanisms, with a reduction in the total energy consumption of 25%. The results showed that the performance improved by 13% in terms of data gathering. Based on the results, the proposed scheme avoids the deafness that occurs in the transmit state in WSNs and increases the data collection throughout the transmission states in WSNs. PMID:28056020

  1. Experimental investigation on a diode-pumped cesium-vapor laser stably operated at continuous-wave and pulse regime.

    Science.gov (United States)

    Chen, Fei; Xu, Dongdong; Gao, Fei; Zheng, Changbin; Zhang, Kuo; He, Yang; Wang, Chunrui; Guo, Jin

    2015-05-04

    Employing a fiber-coupled diode-laser with a center wavelength of 852.25 nm and a line width of 0.17 nm, experimental investigation on diode-end-pumped cesium (Cs) vapor laser stably operated at continuous-wave (CW) and pulse regime is carried out. A 5 mm long cesium vapor cell filled with 60 kPa helium and 20 kPa ethane is used as laser medium. Using an output coupler with reflectivity of 48.79%, 1.26 W 894.57 nm CW laser is obtained at an incident pump power of 4.76 W, corresponding an optical-optical efficiency of 26.8% and a slope-efficiency of 28.8%, respectively. The threshold temperature is 67.5 °C. Stable pulsed cesium laser with a maximum average output power of 2.6 W is obtained at a repetition rate of 76 Hz, and the pulse repetition rate can be extend to 1 kHz with a pulse width of 18 μs.

  2. 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.

  3. PULSE WAVE VELOCITY AND CENTRAL AORTIC PRESSURE IN OBESE CHILDREN ACCORDING TO THE NON-INVASIVE ARTERIOGRAPHY RESULTS

    Directory of Open Access Journals (Sweden)

    O. V. Kozhevnikova

    2013-01-01

    Full Text Available The article presents information value of non-invasive arteriography, which reveals early signs of cardiovascular pathology formation in children, using a large number of trials in children. The authors examined predictors of cardiovascular catastrophes’ development, confirmed in adults: aortic wall’s stiffness, central aortic pressure and pulse pressure – that have not been sufficiently studied in children yet. The article shows that the high-technology method of non-invasive arteriography allows revealing changes of these parameters in children on the preclinical stage. It also shows their correlation with body mass index, fatty hepatosis, direct correlation of weight gain with connection of pulse wave velocity and central blood pressure and importance of follow-up evaluation of these parameters. Heterogeneity of the group of obese children in terms of these parameters is a premise for development of individual approach to control and prevention of cardiovascular complications’ development risk in childhood.

  4. Pulse Pressure, Instead of Brachium-Ankle Pulse Wave Velocity, is Associated with Reduced Kidney Function in a Chinese Han Population

    Directory of Open Access Journals (Sweden)

    Linpei Jia

    2017-03-01

    Full Text Available Background/Aims: In this study, we aim to investigate the association between renal function and arterial stiffness in a Chinese Han population, and further to discuss the effects of smoking on renal function. Methods: We collected the data of the brachium-ankle pulse wave velocity (baPWV, blood pressure, blood chemistry and smoking status. Then, the multiple linear regression was done to explore the relationship between estimated glomerular filtration (eGFR and baPWV. Further, the parameters were compared among the four groups divided according to the quartiles of baPWV. Finally, the baPWV, eGFR and albuminuria values were compared between smokers and non-smokers. Results: baPWV is associated with eGFR in the correlation analysis and univariate linear regression model. After adjustment, the pulse pressure (PP instead of baPWV showed a significant association with eGFR. Nevertheless, the eGFR values differed among the four baPWV groups; the baPWV values were significantly higher in the subjects at the CKD (eGFR<60 mL/min/1.73 m2 and the early CKD stage (eGFR60–80 mL/min/1.73 m2. The baPWV values and the ratio of proteinuria were significantly increased in smokers. Conclusion: PP but not baPWV is a predictor of declined renal function. Smokers have worse arterial stiffness and worse renal function.

  5. Pulse Pressure, Instead of Brachium-Ankle Pulse Wave Velocity, is Associated with Reduced Kidney Function in a Chinese Han Population.

    Science.gov (United States)

    Jia, Linpei; Zhang, Weiguang; Ma, Jie; Chen, Xizhao; Chen, Lei; Li, Zuoxiang; Cai, Guangyan; Huang, Jing; Zhang, Jinping; Bai, Xiaojuan; Feng, Zhe; Sun, Xuefeng; Chen, Xiangmei

    2017-01-01

    In this study, we aim to investigate the association between renal function and arterial stiffness in a Chinese Han population, and further to discuss the effects of smoking on renal function. We collected the data of the brachium-ankle pulse wave velocity (baPWV), blood pressure, blood chemistry and smoking status. Then, the multiple linear regression was done to explore the relationship between estimated glomerular filtration (eGFR) and baPWV. Further, the parameters were compared among the four groups divided according to the quartiles of baPWV. Finally, the baPWV, eGFR and albuminuria values were compared between smokers and non-smokers. baPWV is associated with eGFR in the correlation analysis and univariate linear regression model. After adjustment, the pulse pressure (PP) instead of baPWV showed a significant association with eGFR. Nevertheless, the eGFR values differed among the four baPWV groups; the baPWV values were significantly higher in the subjects at the CKD (eGFRfunction. Smokers have worse arterial stiffness and worse renal function. © 2017 The Author(s)Published by S. Karger AG, Basel.

  6. Measurements of the plasma density in the FTU tokamak by a pulsed time-of-flight X-wave refractometer

    International Nuclear Information System (INIS)

    Petrov, V. G.; Petrov, A. A.; Malyshev, A. Yu.; De Benedetti, M.; Tudisco, O.

    2008-01-01

    On-line control over the plasma density in tokamaks (especially, in long-term discharges) requires reliable measurements of the averaged plasma density. For this purpose, a new method of density measurements-a pulsed time-of-flight plasma refractometry-was developed and tested in the T-11M tokamak. This method allows one to determine the averaged density from the measured time delay of nanosecond microwave pulses propagating through the plasma. For an O-wave, the measured time delay is proportional to the line-averaged density and is independent of the density profile (f>>f p ) τ o ∼ k o 1/f 2 ∫ l N(x)dx. Here, f is the frequency of the probing wave, f p is the plasma frequency, l= 4 a is the path length for two-pass probing in the equatorial plane, a is the plasma minor radius, k O and k X are numerical factors, f c is the electron-cyclotron frequency at the axis of the plasma column, and f p >>f c , f. Measurements of the time delay provide the same information as plasma interferometry, though they do no employ the effect of interference. When the conditions f p >>f c , f are not satisfied, the measured time delay depends on the shape of the density profile. In this case, in order to determine the average density regardless of the density profile, it is necessary to perform simultaneous measurements at several probing frequencies in order to determine the average density. In ITER (Bt ∼ 5T), a spectral window between the lower and upper cutoff frequencies in the range of 50-100 GHz can be used for pulsed time-of-flight X-wave refractometry. This appreciably simplifies the diagnostics and eliminates the problem of the first mirror. In this paper, the first results obtained in the FTU tokamak with a prototype of the ITER pulsed time-of-flight refractometer are presented. The geometry and layout of experiments similar to the planned ITER experiments are described. The density measured by pulsed time-of-flight refractometry is shown to agree well with the

  7. 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

  8. SiOx Ink-Repellent Layer Deposited by Radio Frequency (RF) Plasmas in Continuous Wave and Pulse Mode

    International Nuclear Information System (INIS)

    Chen Qiang; Fu Yabo; Pang Hua; Zhang Yuefei; Zhang Guangqiu

    2007-01-01

    Low surface energy layers, proposed application for non-water printing in computer to plate (CTP) technology, are deposited in both continuous wave and pulse radio frequency (13.56 MHz) plasma with hexamethyldisiloxane (HMDSO) as precursor. It is found that the plasma mode dominates the polymer growth rate and the surface composition. Derived from the spectra of X-ray photoelectron spectroscopy (XPS) and combined with printable test it is concluded that concentration of Si in coatings plays an important role for the ink printability and the ink does not adhere on the surface with high silicon concentration

  9. Ultrasound Pulsed-Wave Doppler Detects an Intrathecal Location of an Epidural Catheter Tip: A Case Report.

    Science.gov (United States)

    Elsharkawy, Hesham; Saasouh, Wael; Patel, Bimal; Babazade, Rovnat

    2018-04-01

    Currently, no gold standard method exists for localization of an epidural catheter after placement. The technique described in this report uses pulsed-wave Doppler (PWD) ultrasound to identify intrathecal location of an epidural catheter. A thoracic epidural catheter was inserted after multiple trials with inconclusive aspiration and test dose. Ultrasound PWD confirmed no flow in the epidural space and positive flow in the intrathecal space. A fluid aspirate was positive for glucose, reconfirming intrathecal placement. PWD is a potential tool that can be used to locate the tip of an epidural catheter.

  10. Effects of shock waves, ultraviolet light, and electric fields from pulsed discharges in water on inactivation of Escherichia coli.

    Science.gov (United States)

    Sun, Bing; Xin, Yanbin; Zhu, Xiaomei; Gao, Zhiying; Yan, Zhiyu; Ohshima, Takayuki

    2018-04-01

    In this work, the bacterial inactivation effects of shock waves, ultraviolet (UV) light, and electric field produced by high-voltage pulsed discharge in liquid with needle-plate configurations were studied. The contributions of each effect on the bacterial killing ratio in the discharge process were obtained individually by modifying reactor type and usage of glass, quartz, and black balloons. The results showed that the location from the discharge center axis significantly influenced the effects of shock waves and electric fields, although the effect of UV light was not affected by the location in the reactor. The effects of shock waves and electric fields were improved by decreasing the distance from the discharge center axis. Under this experimental condition, the effects of shock waves, UV light, and electric fields produced by discharges on bacterial inactivation were approximately 36.1%, 30.8%, 12.7%, respectively. Other contributions seemed to be due to activated species. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Central Arterial Function Measured by Non-invasive Pulse Wave Analysis is Abnormal in Patients with Duchenne Muscular Dystrophy.

    Science.gov (United States)

    Ryan, Thomas D; Parent, John J; Gao, Zhiqian; Khoury, Philip R; Dupont, Elizabeth; Smith, Jennifer N; Wong, Brenda; Urbina, Elaine M; Jefferies, John L

    2017-08-01

    Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder caused by mutation of dystrophin. Cardiovascular involvement includes dilated cardiomyopathy. Non-invasive assessment of vascular function has not been evaluated in DMD. We hypothesize arterial wave reflection is abnormal in patients with DMD. Pulse wave analysis was performed on DMD patients with a SphygmoCor SCOR-PVx System to determine central blood pressure and augmentation index (AIx) as an assessment of arterial wave reflection. Results were compared to a control group. A total of 43 patients with DMD were enrolled, and compared to 43 normal controls. Central systolic blood pressure was lower, while both AIx-75 (7.8 ± 9.6% vs. 2.1 ± 10.4%, p 0.01, DMD vs. normal) and AIx-not corrected (16.8 ± 10.1% vs. -3.6 ± 10.9, p wave reflection when compared to normal controls, which may represent increased arterial stiffness. Overall there appears to be no effect on ventricular systolic function, however the long-term consequence in this group is unknown. Further study is required to determine the mechanism of these differences, which may be related to the effects of systemic steroids or the role of dystrophin in vascular function.

  12. 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

  13. Histologic evaluation of laser lipolysis comparing continuous wave vs pulsed lasers in an in vivo pig model.

    Science.gov (United States)

    Levi, Jessica R; Veerappan, Anna; Chen, Bo; Mirkov, Mirko; Sierra, Ray; Spiegel, Jeffrey H

    2011-01-01

    To evaluate acute and delayed laser effects of subdermal lipolysis and collagen deposition using an in vivo pig model and to compare histologic findings in fatty tissue after continuous wave diode (CW) vs pulsed laser treatment. Three CW lasers (980, 1370, and 1470 nm) and 3 pulsed lasers (1064, 1320, and 1440 nm) were used to treat 4 Göttingen minipigs. Following administration of Klein tumescent solution, a laser cannula was inserted at the top of a 10 × 2.5-cm rectangle and was passed subdermally to create separate laser "tunnels." Temperatures at the surface and at intervals of 4-mm to 20-mm depths were recorded immediately after exposure and were correlated with skin injury. Full-thickness cutaneous biopsy specimens were obtained at 1 day, 1 week, and 1 month after exposure and were stained with hematoxylin-eosin and trichrome stain. Qualitative and semiquantitative histopathologic evaluations were performed with attention to vascular damage, lipolysis, and collagen deposition. Skin surface damage occurred at temperatures exceeding 46°C. Histologic examination at 1 day after exposure showed hemorrhage, fibrous collagen fiber coagulation, and adipocyte damage. Adipocytes surrounded by histiocytes, a marker of lipolysis, were present at 1 week and 1 month after exposure. Collagen deposition in subdermal fatty tissue and in reticular dermis of some specimens was noted at 1 week and had increased at 1 month. Tissue treated with CW laser at 1470 nm demonstrated greater hemorrhage and more histiocytes at damage sites than tissue treated with pulsed laser at 1440 nm. There was a trend toward more collagen deposition with pulsed lasers than with CW lasers, but this was not statistically significant. Histopathologic comparison between results of CW laser at 980 nm vs pulsed laser at 1064 nm showed the same trend. Hemorrhage differences may result from pulse duration variations. A theoretical calculation estimating temperature rise in vessels supported this

  14. Pulsed TV holography measurement and digital reconstruction of compression acoustic wave fields: application to nondestructive testing of thick metallic samples

    International Nuclear Information System (INIS)

    Trillo, C; Doval, A F; Deán-Ben, X L; López-Vázquez, J C; Fernández, J L; Hernández-Montes, S

    2011-01-01

    This paper describes a technique that numerically reconstructs the complex acoustic amplitude (i.e. the acoustic amplitude and phase) of a compression acoustic wave in the interior volume of a specimen from a set of full-field optical measurements of the instantaneous displacement of the surface. The volume of a thick specimen is probed in transmission mode by short bursts of narrowband compression acoustic waves generated at one of its faces. The temporal evolution of the displacement field induced by the bursts emerging at the opposite surface is measured by pulsed digital holographic interferometry (pulsed TV holography). A spatio-temporal 3D Fourier transform processing of the measured data yields the complex acoustic amplitude at the plane of the surface as a sequence of 2D complex-valued maps. Finally, a numerical implementation of the Rayleigh–Sommerfeld diffraction formula is employed to reconstruct the complex acoustic amplitude at other planes in the interior volume of the specimen. The whole procedure can be regarded as a combination of optical digital holography and acoustical holography methods. The technique was successfully tested on aluminium specimens with and without an internal artificial defect and sample results are presented. In particular, information about the shape and position of the defect was retrieved in the experiment performed on the flawed specimen, which indicates the potential applicability of the technique for the nondestructive testing of materials

  15. 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 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.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.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.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.

  16. Isomer-specific detection in the UV photodissociation of the propargyl radical by chirped-pulse mm-wave spectroscopy in a pulsed quasi-uniform flow.

    Science.gov (United States)

    Broderick, Bernadette M; Suas-David, Nicolas; Dias, Nureshan; Suits, Arthur G

    2018-02-21

    Isomer-specific detection and product branching fractions in the UV photodissociation of the propargyl radical is achieved through the use of chirped-pulse Fourier-transform mm-wave spectroscopy in a pulsed quasi-uniform flow (CPUF). Propargyl radicals are produced in the 193 nm photodissociation of 1,2-butadiene. Absorption of a second photon leads to H atom elimination giving three possible C 3 H 2 isomers: singlets cyclopropenylidene (c-C 3 H 2 ) and propadienylidene (l-C 3 H 2 ), and triplet propargylene ( 3 HCCCH). The singlet products and their appearance kinetics in the flow are directly determined by rotational spectroscopy, but due to the negligible dipole moment of propargylene, it is not directly monitored. However, we exploit the time-dependent kinetics of H-atom catalyzed isomerization to infer the branching to propargylene as well. We obtain the overall branching among H loss channels to be 2.9% (+1.1/-0.5) l-C 3 H 2 + H, 16.8% (+3.2/-1.3) c-C 3 H 2 + H, and 80.2 (+1.8/-4.2) 3 HCCCH + H. Our findings are qualitatively consistent with earlier RRKM calculations in that the major channel in the photodissociation of the propargyl radical at 193 nm is to 3 HCCCH + H; however, a greater contribution to the energetically most favorable isomer, c-C 3 H 2 + H is observed in this work. We do not detect the predicted HCCC + H 2 channel, but place an upper bound on its yield of 1%.

  17. Crystal Growth of High-Quality Protein Crystals under the Presence of an Alternant Electric Field in Pulse-Wave Mode, and a Strong Magnetic Field with Radio Frequency Pulses Characterized by X-ray Diffraction

    Directory of Open Access Journals (Sweden)

    Adela Rodríguez-Romero

    2017-06-01

    Full Text Available The first part of this research was devoted to investigating the effect of alternate current (AC using four different types of wave modes (pulse-wave at 2 Hz on the crystal growth of lysozyme in solution. The best results, in terms of size and crystal quality, were obtained when protein crystals were grown under the influence of electric fields in a very specific wave mode (“breathing” wave, giving the highest resolution up to 1.34 Å in X-ray diffraction analysis compared with controls and with those crystals grown in gel. In the second part, we evaluated the effect of a strong magnetic field of 16.5 Tesla combined with radiofrequency pulses of 0.43 μs on the crystal growth in gels of tetragonal hen egg white (HEW lysozyme. The lysozyme crystals grown, both in solution applying breathing-wave and in gel under the influence of this strong magnetic field with pulses of radio frequencies, produced the larger-in-size crystals and the highest resolution structures. Data processing and refinement statistics are very good in terms of the resolution, mosaicity and Wilson B factor obtained for each crystal. Besides, electron density maps show well-defined and distinctly separated atoms at several selected tryptophan residues for the crystal grown using the “breathing wave pulses”.

  18. Cavitation and shock waves emission on the rigid boundary of water under mid-IR nanosecond laser pulse excitation

    Science.gov (United States)

    Pushkin, A. V.; Bychkov, A. S.; Karabutov, A. A.; Potemkin, F. V.

    2018-06-01

    The processes of conversion of light energy into mechanical energy under mid-IR nanosecond laser excitation on a rigid boundary of water are investigated. Strong water absorption of Q-switched Cr:Yb:Ho:YSGG (2.85 µm, 6 mJ, 45 ns) laser radiation provides rapid energy deposition of ~8 kJ cm‑3 accompanied with strong mechanical transients. The evolution of shock waves and cavitation bubbles is studied using the technique of shadowgraphy and acoustic measurements, and the conversion efficiency into these energy channels for various laser fluence (0.75–2.0 J cm‑2) is calculated. For 6 mJ laser pulse with fluence of 2.0 J cm‑2, the conversion into shock wave energy reaches 67%. The major part of the shock wave energy (92%) is dissipated when the shock front travels the first 250 µm, and the remaining 8% is transferred to the acoustic far field. The calculated pressure in the vicinity of water-silicon interface is 0.9 GPa. Cavitation efficiency is significantly less and reaches up to 5% of the light energy. The results of the current study could be used in laser parameters optimization for micromachining and biological tissue ablation.

  19. Molecular dynamics simulation of shock wave and spallation phenomena in metal foils irradiated by femtosecond laser pulse

    Science.gov (United States)

    Zhakhovsky, Vasily; Demaske, Brian; Inogamov, Nail; Oleynik, Ivan

    2010-03-01

    Femtosecond laser irradiation of metals is an effective technique to create a high-pressure frontal layer of 100-200 nm thickness. The associated ablation and spallation phenomena can be studied in the laser pump-probe experiments. We present results of a large-scale MD simulation of ablation and spallation dynamics developing in 1,2,3μm thick Al and Au foils irradiated by a femtosecond laser pulse. Atomic-scale mechanisms of laser energy deposition, transition from pressure wave to shock, reflection of the shock from the rear-side of the foil, and the nucleation of cracks in the reflected tensile wave, having a very high strain rate, were all studied. To achieve a realistic description of the complex phenomena induced by strong compression and rarefaction waves, we developed new embedded atom potentials for Al and Au based on cold pressure curves. MD simulations revealed the complex interplay between spallation and ablation processes: dynamics of spallation depends on the pressure profile formed in the ablated zone at the early stage of laser energy absorption. It is shown that the essential information such as material properties at high strain rate and spall strength can be extracted from the simulated rear-side surface velocity as a function of time.

  20. 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

  1. Assessment of macrovascular endothelial function using pulse wave analysis and its association with microvascular reactivity in healthy subjects.

    Science.gov (United States)

    Ibrahim, N N I N; Rasool, A H G

    2017-08-01

    Pulse wave analysis (PWA) and laser Doppler fluximetry (LDF) are non-invasive methods of assessing macrovascular endothelial function and microvascular reactivity respectively. The aim of this study was to assess the correlation between macrovascular endothelial function assessed by PWA and microvascular reactivity assessed by LDF. 297 healthy and non-smoking subjects (159 females, mean age (±SD) 23.56 ± 4.54 years) underwent microvascular reactivity assessment using LDF followed by macrovascular endothelial function assessments using PWA. Pearson's correlation showed no correlation between macrovascular endothelial function and microvascular reactivity (r = -0.10, P = 0.12). There was no significant correlation between macrovascular endothelial function assessed by PWA and microvascular reactivity assessed by LDF in healthy subjects. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Impact of ADMA, endothelial progenitor cells and traditional cardiovascular risk factors on pulse wave velocity among prediabetic individuals

    Directory of Open Access Journals (Sweden)

    Protopsaltis Ioannis

    2012-11-01

    Full Text Available Abstract Background Central arterial stiffness represents a well-established predictor of cardiovascular disease. Decreased circulating endothelial progenitor cells (EPCs, increased asymmetric dimethyl-arginine (ADMA levels, traditional cardiovascular risk factors and insulin resistance have all been associated with increased arterial stiffness. The correlations of novel and traditional cardiovascular risk factors with central arterial stiffness in prediabetic individuals were investigated in the present study. Methods The study population consisted of 53 prediabetic individuals. Individuals were divided into groups of isolated impaired fasting glucose (IFG, isolated impaired glucose tolerance (IGT and combined IGT-IFG. Age, sex, family history of diabetes, smoking history, body mass index (BMI, waist to hip ratio (WHR, waist circumference (WC, blood pressure, lipid profile, levels of high sensitive C-reactive protein (hsCRP, glomerular filtration rate (GFR, and history of antihypertensive or statin therapy were obtained from all participants. Insulin resistance was evaluated using the Homeostatic Model Assessment (HOMA-IR. Carotid -femoral pulse wave velocity was used as an index of arterial stiffness. Circulating EPC count and ADMA serum levels were also determined. Results Among studied individuals 30 (56.6% subjects were diagnosed with isolated IFG, 9 (17% with isolated IGT (17% and 14 with combined IFG-IGT (26.4%. In univariate analysis age, mean blood pressure, fasting glucose, total cholesterol, LDL cholesterol, and ADMA levels positively correlated with pulse-wave velocity while exercise and GFR correlated negatively. EPC count did not correlate with PWV. In multivariate stepwise regression analysis PWV correlated independently and positively with LDL-Cholesterol (low density lipoprotein and ADMA levels and negatively with exercise. Conclusions Elevated ADMA and LDL-C levels are strongly associated with increased arterial stiffness among

  3. 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.

  4. Performance of a reflectometer at continuous wave and pulsed neutron sources

    International Nuclear Information System (INIS)

    Fitzsimmons, M.R.

    1995-01-01

    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

  5. 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...

  6. Evaluation of arterial stiffness by finger-toe pulse wave velocity: optimization of signal processing and clinical validation.

    Science.gov (United States)

    Obeid, Hasan; Khettab, Hakim; Marais, Louise; Hallab, Magid; Laurent, Stéphane; Boutouyrie, Pierre

    2017-08-01

    Carotid-femoral pulse wave velocity (PWV) (cf-PWV) is the gold standard for measuring aortic stiffness. Finger-toe PWV (ft-PWV) is a simpler noninvasive method for measuring arterial stiffness. Although the validity of the method has been previously assessed, its accuracy can be improved. ft-PWV is determined on the basis of a patented height chart for the distance and the pulse transit time (PTT) between the finger and the toe pulpar arteries signals (ft-PTT). The objective of the first study, performed in 66 patients, was to compare different algorithms (intersecting tangents, maximum of the second derivative, 10% threshold and cross-correlation) for determining the foot of the arterial pulse wave, thus the ft-PTT. The objective of the second study, performed in 101 patients, was to investigate different signal processing chains to improve the concordance of ft-PWV with the gold-standard cf-PWV. Finger-toe PWV (ft-PWV) was calculated using the four algorithms. The best correlations relating ft-PWV and cf-PWV, and relating ft-PTT and carotid-femoral PTT were obtained with the maximum of the second derivative algorithm [PWV: r = 0.56, P < 0.0001, root mean square error (RMSE) = 0.9 m/s; PTT: r = 0.61, P < 0.001, RMSE = 12 ms]. The three other algorithms showed lower correlations. The correlation between ft-PTT and carotid-femoral PTT further improved (r = 0.81, P < 0.0001, RMSE = 5.4 ms) when the maximum of the second derivative algorithm was combined with an optimized signal processing chain. Selecting the maximum of the second derivative algorithm for detecting the foot of the pressure waveform, and combining it with an optimized signal processing chain, improved the accuracy of ft-PWV measurement in the current population sample. Thus, it makes ft-PWV very promising for the simple noninvasive determination of aortic stiffness in clinical practice.

  7. Continuous-wave to pulse regimes for a family of passively mode-locked lasers with saturable nonlinearity

    Science.gov (United States)

    Dikandé, Alain M.; Voma Titafan, J.; Essimbi, B. Z.

    2017-10-01

    The transition dynamics from continuous-wave to pulse regimes of operation for a generic model of passively mode-locked lasers with saturable absorbers, characterized by an active medium with non-Kerr nonlinearity, are investigated analytically and numerically. The system is described by a complex Ginzburg-Landau equation with a general m:n saturable nonlinearity (i.e {I}m/{(1+{{Γ }}I)}n, where I is the field intensity and m and n are two positive numbers), coupled to a two-level gain equation. An analysis of stability of continuous waves, following the modulational instability approach, provides a global picture of the self-starting dynamics in the system. The analysis reveals two distinct routes depending on values of the couple (m, n), and on the dispersion regime: in the normal dispersion regime, when m = 2 and n is arbitrary, the self-starting requires positive values of the fast saturable absorber and nonlinearity coefficients, but negative values of these two parameters for the family with m = 0. However, when the spectral filter is negative, the laser can self-start for certain values of the input field and the nonlinearity saturation coefficient Γ. The present work provides a general map for the self-starting mechanisms of rare-earth doped figure-eight fiber lasers, as well as Kerr-lens mode-locked solid-state lasers.

  8. Validation of the inverse pulse wave transit time series as surrogate of systolic blood pressure in MVAR modeling.

    Science.gov (United States)

    Giassi, Pedro; Okida, Sergio; Oliveira, Maurício G; Moraes, Raimes

    2013-11-01

    Short-term cardiovascular regulation mediated by the sympathetic and parasympathetic branches of the autonomic nervous system has been investigated by multivariate autoregressive (MVAR) modeling, providing insightful analysis. MVAR models employ, as inputs, heart rate (HR), systolic blood pressure (SBP) and respiratory waveforms. ECG (from which HR series is obtained) and respiratory flow waveform (RFW) can be easily sampled from the patients. Nevertheless, the available methods for acquisition of beat-to-beat SBP measurements during exams hamper the wider use of MVAR models in clinical research. Recent studies show an inverse correlation between pulse wave transit time (PWTT) series and SBP fluctuations. PWTT is the time interval between the ECG R-wave peak and photoplethysmography waveform (PPG) base point within the same cardiac cycle. This study investigates the feasibility of using inverse PWTT (IPWTT) series as an alternative input to SBP for MVAR modeling of the cardiovascular regulation. For that, HR, RFW, and IPWTT series acquired from volunteers during postural changes and autonomic blockade were used as input of MVAR models. Obtained results show that IPWTT series can be used as input of MVAR models, replacing SBP measurements in order to overcome practical difficulties related to the continuous sampling of the SBP during clinical exams.

  9. 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)

    Eichhorn, J.G.; Ruediger, H.J.; Gorenflo, M.; Khalil, M.; Ulmer, H.; Krissak, R.; Kauczor, H.U.; Ley, S.; Universitaetsklinik Heidelberg; Arnold, R.; Universitaetskinderklinik Freiburg; Boese, J.; Siemens AG, Medical Solutions, Forchheim; Krug, R.; Fink, C.

    2007-01-01

    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 (χ 2 -test, p = 0.0002) using an age-related non-linear regression analysis. The related aortic compliance was significantly decreased (χ 2 -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.)

  10. 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 ...

  11. 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

  12. Cross-correlation analysis of pulse wave propagation in arteries: in vitro validation and in vivo feasibility.

    Science.gov (United States)

    Nauleau, Pierre; Apostolakis, Iason; McGarry, Matthew; Konofagou, Elisa

    2018-05-29

    The stiffness of the arteries is known to be an indicator of the progression of various cardiovascular diseases. Clinically, the pulse wave velocity (PWV) is used as a surrogate for arterial stiffness. Pulse wave imaging (PWI) is a non-invasive, ultrasound-based imaging technique capable of mapping the motion of the vessel walls, allowing the local assessment of arterial properties. Conventionally, a distinctive feature of the displacement wave (e.g. the 50% upstroke) is tracked across the map to estimate the PWV. However, the presence of reflections, such as those generated at the carotid bifurcation, can bias the PWV estimation. In this paper, we propose a two-step cross-correlation based method to characterize arteries using the information available in the PWI spatio-temporal map. First, the area under the cross-correlation curve is proposed as an index for locating the regions of different properties. Second, a local peak of the cross-correlation function is tracked to obtain a less biased estimate of the PWV. Three series of experiments were conducted in phantoms to evaluate the capabilities of the proposed method compared with the conventional method. In the ideal case of a homogeneous phantom, the two methods performed similarly and correctly estimated the PWV. In the presence of reflections, the proposed method provided a more accurate estimate than conventional processing: e.g. for the soft phantom, biases of  -0.27 and -0.71 m · s -1 were observed. In a third series of experiments, the correlation-based method was able to locate two regions of different properties with an error smaller than 1 mm. It also provided more accurate PWV estimates than conventional processing (biases:  -0.12 versus -0.26 m · s -1 ). Finally, the in vivo feasibility of the proposed method was demonstrated in eleven healthy subjects. The results indicate that the correlation-based method might be less precise in vivo but more accurate than the conventional method.

  13. 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......:YAG laser incorporating a periodically poled LiNbO3 (PPLN) crystal inside the laser cavity to take advantage of the high circulating intracavity field. The Yb:YAG crystal is pumped by a reliable 940 nm fibre-coupled diode laser. The IOPO consists of a Yb:YAG crystal coated for HR at 1030 nm, an intracavity...... lens to generate a beam waist in the PPLN crystal, a dichroic mirror to separate the laser and signal fields and two end mirrors...

  14. A 10 TW pulsed energy complex PIRIT-2000 for investigation of short-wave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Popkov, N F; Ryaslov, E A; Kargin, V I; Pikar` , A S; Vorontsov, V I; Kotel` nikov, D V; Melkozerov, A V [All-Russian Scientific Research Inst. of Experimental Physics, Sarov (Russian Federation)

    1997-12-31

    The results of investigation of a pulsed plasma x-ray source at the PIRIT-2000 fast operating capacitor bank are reported. The maximum energy stored in a primary 54-module capacitive storage at the output voltage of 500 kV reaches 2 MJ. The capacitor bank energizes a vacuum inductive storage, which is commutated by a plasma opening switch. The plasma diode consists of a tube cathode of diameter 15 cm and of a larger tube anode with six plasma injecting guns. The current amplitude and the current rise time at the plasma load amounts to 4 MA and 150 ns, respectively. The x-ray doses were measured by means of thermoluminescent dosemeters and the integral radiation output by means of a thermocouple calorimeter. The radiation output as high as 100 kJ was achieved at the stored energy of 1 MJ. (J.U.). 4 figs., 4 refs.

  15. Resonant parametric interference effect in 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.

    2018-04-01

    Electron-nucleus bremsstrahlung in the field of two moderately strong pulsed laser waves in the case of incommensurate frequencies is theoretically studied under resonant conditions. The process is studied in detail in a special kinematic region, where stimulated processes with correlated emission and absorption of photons of the first and second waves become predominant (parametric interference effect). The availability of this region is caused by interference of the first and second laser waves. The correspondence between the emission angle and the final-electron energy is established in this interference kinematic. In this case, the cross-sectional properties are determined by the multiphoton quantum interference parameter, which is proportional to the product of intensities of the first and second waves. The resonant differential cross section of electron-nucleus spontaneous bremsstrahlung with simultaneous registration of both emission angles of the spontaneous photon and the scattered electron can exceed by four or five orders of magnitude the corresponding cross section in the absence of an external field. It was shown for nonrelativistic electrons that the resonant cross section of the studied process in the field of two pulsed laser waves within the interference region in two order of magnitude may exceed corresponding cross sections at other scattering kinematics. The obtained results may be experimentally verified, for example, by scientific facilities at sources of pulsed laser radiation (such as SLAC, FAIR, XFEL, ELI).

  16. 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.

  17. Pulse Wave Velocity as Marker of Preclinical Arterial Disease: Reference Levels in a Uruguayan Population Considering Wave Detection Algorithms, Path Lengths, Aging, and Blood Pressure

    Directory of Open Access Journals (Sweden)

    Ignacio Farro

    2012-01-01

    Full Text Available Carotid-femoral pulse wave velocity (PWV has emerged as the gold standard for non-invasive evaluation of aortic stiffness; absence of standardized methodologies of study and lack of normal and reference values have limited a wider clinical implementation. This work was carried out in a Uruguayan (South American population in order to characterize normal, reference, and threshold levels of PWV considering normal age-related changes in PWV and the prevailing blood pressure level during the study. A conservative approach was used, and we excluded symptomatic subjects; subjects with history of cardiovascular (CV disease, diabetes mellitus or renal failure; subjects with traditional CV risk factors (other than age and gender; asymptomatic subjects with atherosclerotic plaques in carotid arteries; patients taking anti-hypertensives or lipid-lowering medications. The included subjects (n=429 were categorized according to the age decade and the blood pressure levels (at study time. All subjects represented the “reference population”; the group of subjects with optimal/normal blood pressures levels at study time represented the “normal population.” Results. Normal and reference PWV levels were obtained. Differences in PWV levels and aging-associated changes were obtained. The obtained data could be used to define vascular aging and abnormal or disease-related arterial changes.

  18. A 4 MA, 500 ns pulsed power generator CQ-4 for characterization of material behaviors under ramp wave loading.

    Science.gov (United States)

    Wang, Guiji; Luo, Binqiang; Zhang, Xuping; Zhao, Jianheng; Sun, Chengwei; Tan, Fuli; Chong, Tao; Mo, Jianjun; Wu, Gang; Tao, Yanhui

    2013-01-01

    A pulsed power generator CQ-4 was developed to characterize dynamic behaviors of materials under ramp wave loading, and to launch high velocity flyer plates for shock compression and hypervelocity impact experiments of materials and structures at Institute of Fluid Physics, China Academy of Engineering Physics. CQ-4 is composed of twenty capacitor and primary discharge switch modules with total capacitance of 32 μF and rated charging voltage of 100 kV, and the storage energy is transmitted by two top and bottom parallel aluminum plates insulated by twelve layers of polyester film with total thickness of 1.2 mm. Between capacitor bank and chamber, there are 72 peaking capacitors with total capacitance of 7.2 μF and rated voltage of 120 kV in parallel, which are connected with the capacitor bank in parallel. Before the load, there is a group of seven secondary self-breaking down switches connected with the total circuit in series. The peaking capacitors and secondary switches are used to shape the discharging current waveforms. For short-circuit, the peak current of discharging can be up to 3 ~ 4 MA and rise time varies from 470 ns to 600 ns when the charging voltages of the generator are from 75 kV to 85 kV. With CQ-4 generator, some quasi-isentropic compression experiments under ramp wave loadings are done to demonstrate the ability of CQ-4 generator. And some experiments of launching high velocity flyer plates are also done on CQ-4. The experimental results show that ramp wave loading pressure of several tens of GPa on copper and aluminum samples can be realized and the velocity of aluminum flyer plate with size of 10 mm × 6 mm × 0.35 mm can be accelerated to about 11 km/s and the velocity of aluminum flyer plate with size of 10 mm × 6 mm × 0.6 mm can be up to about 9 km/s, which show that CQ-4 is a good and versatile tool to realize ramp wave loading and shock compression for shock physics.

  19. An inductive narrow-pulse RFID telemetry system for gastric slow waves monitoring.

    Science.gov (United States)

    Javan-Khoskholgh, Amir; Abukhalaf, Zaid; Ji Li; Miller, Larry S; Kiani, Mehdi; Farajidavar, Aydin

    2016-08-01

    We present a passive data telemetry system for real-time monitoring of gastric electrical activity of a living subject. The system is composed of three subsystems: an implantable unit (IU), a wearable unit (WU), and a stationary unit (SU). Data communication between the IU and WU is based on a radio-frequency identification (RFID) link operating at 13.56 MHz. Since wireless power transmission and reverse data telemetry system share the same inductive interface, a load shift keying (LSK)-based differential pulse position (DPP) coding data communication with only 6.25% duty cycle is developed to guarantee consistent wireless downlink power transmission and uplink high data transfer rate, simultaneously. The clock and data are encoded into one signal by an MSP430 microcontroller (MCU) at the IU side. This signal is sent to the WU through the inductive link, where decoded by an MSP432 MCU. Finally, the retrieved data at the WU are transmitted to the SU connected to a PC via a 2.4 GHz transceiver for real-time display and analysis. The results of the measurements on the implemented test bench, demonstrate IU-WU 125 kb/s and WU-SU 2 Mb/s data transmission rate with no observed mismatch, while the data stream was randomly generated, and matching between the transmitted data by the IU and received by the SU verified by a custom-made automated software.

  20. A 10-TW Pulsed Facility "PIRIT" for Investigation of Short-Wave Radiation Generation.

    Science.gov (United States)

    Popkov, N F; Ryaslov, E A; Kargin, V I; Pikar', A S; Kotel'nikov, D V; Melkozerov, A V

    1995-01-01

    The results of experiments with a plasma x-ray source in the PIRIT-2000 facility are presented in this paper. The facility is designed with module capacitive energy storage energizing vacuum inductive storage. The formation of a rapidly growing current pulse as well as its commutation on a load was carried out by a plasma opening switch. A vacuum diode as well as various types of plasma loads can be used for the generation of a high-power x-ray flux. The storage energy of a 54-module capacitive storage is up to 2 MJ, its inductance is 15 nH, and its output voltage is 500 kV. The peak current in the plasma load constituted 4 MA with a 150-ns rise time. The maximum integral energy output of x radiation measured by an open thermocouple calorimeter was as high as 100 kJ, while the primary storage energy was 1 MJ. The plasma load usage at a current of 4 MA ensured a 100-kJ generation in x-ray radiation and the density of the radiation flux at a distance of 1 m from the source was as much as 0.8 J/cm2, while near the source it was 10 J/cm2.

  1. 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

    2016-04-04

    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.

  2. 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.

  3. CSF in the ventricles of the brain behaves as a relay medium for arteriovenous pulse wave phase coupling.

    Directory of Open Access Journals (Sweden)

    William E Butler

    Full Text Available The ventricles of the brain remain perhaps the largest anatomic structure in the human body without established primary purpose, even though their existence has been known at least since described by Aristotle. We hypothesize that the ventricles help match a stroke volume of arterial blood that arrives into the rigid cranium with an equivalent volume of ejected venous blood by spatially configuring cerebrospinal fluid (CSF to act as a low viscosity relay medium for arteriovenous pulse wave (PW phase coupling. We probe the hypothesis by comparing the spatiotemporal behavior of vascular PW about the ventricular surfaces in piglets to internal observations of ventricle wall motions and adjacent CSF pressure variations in humans. With wavelet brain angiography data obtained from piglets, we map the travel relative to brain pulse motion of arterial and venous PWs over the ventricle surfaces. We find that arterial PWs differ in CF phase from venous PWs over the surfaces of the ventricles consistent with arteriovenous PW phase coupling. We find a spatiotemporal difference in vascular PW phase between the ventral and dorsal ventricular surfaces, with the PWs arriving slightly sooner to the ventral surfaces. In humans undergoing neuroendoscopic surgery for hydrocephalus, we measure directly ventricle wall motions and the adjacent internal CSF pressure variations. We find that CSF pressure peaks slightly earlier in the ventral Third Ventricle than the dorsal Lateral Ventricle. When matched anatomically, the peri-ventricular vascular PW phase distribution in piglets complements the endo-ventricular CSF PW phase distribution in humans. This is consistent with a role for the ventricles in arteriovenous PW coupling and may add a framework for understanding hydrocephalus and other disturbances of intracranial pressure.

  4. A Pulse Wave Velocity Based Method to Assess the Mean Arterial Blood Pressure Limits of Autoregulation in Peripheral Arteries

    Directory of Open Access Journals (Sweden)

    Ananya Tripathi

    2017-11-01

    Full Text Available Background: Constant blood flow despite changes in blood pressure, a phenomenon called autoregulation, has been demonstrated for various organ systems. We hypothesized that by changing hydrostatic pressures in peripheral arteries, we can establish these limits of autoregulation in peripheral arteries based on local pulse wave velocity (PWV.Methods: Electrocardiogram and plethysmograph waveforms were recorded at the left and right index fingers in 18 healthy volunteers. Each subject changed their left arm position, keeping the right arm stationary. Pulse arrival times (PAT at both fingers were measured and used to calculate PWV. We calculated ΔPAT (ΔPWV, the differences between the left and right PATs (PWVs, and compared them to the respective calculated blood pressure at the left index fingertip to derive the limits of autoregulation.Results: ΔPAT decreased and ΔPWV increased exponentially at low blood pressures in the fingertip up to a blood pressure of 70 mmHg, after which changes in ΔPAT and ΔPWV were minimal. The empirically chosen 20 mmHg window (75–95 mmHg was confirmed to be within the autoregulatory limit (slope = 0.097, p = 0.56. ΔPAT and ΔPWV within a 20 mmHg moving window were not significantly different from the respective data points within the control 75–95 mmHg window when the pressure at the fingertip was between 56 and 110 mmHg for ΔPAT and between 57 and 112 mmHg for ΔPWV.Conclusions: Changes in hydrostatic pressure due to changes in arm position significantly affect peripheral arterial stiffness as assessed by ΔPAT and ΔPWV, allowing us to estimate peripheral autoregulation limits based on PWV.

  5. The venous manifestations of pulse wave encephalopathy: windkessel dysfunction in normal aging and senile dementia

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, Grant A. [Locked Bag 1, Newcastle Region Mail Center, Department of Medical Imaging, John Hunter Hospital, Newcastle (Australia); Levi, Christopher R.; Wang, Yang; Lovett, Elizabeth C. [Hunter Medical Research Institute, Clinical Neurosciences Program, Newcastle (Australia); Schofield, Peter [James Fletcher Hospital, Neuropsychiatry Unit, Newcastle (Australia)

    2008-06-15

    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.)

  6. The effect of venous pulsation on the forehead pulse oximeter wave form as a possible source of error in Spo2 calculation.

    Science.gov (United States)

    Shelley, Kirk H; Tamai, Doris; Jablonka, Denis; Gesquiere, Michael; Stout, Robert G; Silverman, David G

    2005-03-01

    Reflective forehead pulse oximeter sensors have recently been introduced into clinical practice. They reportedly have the advantage of faster response times and immunity to the effects of vasoconstriction. Of concern are reports of signal instability and erroneously low Spo(2) values with some of these new sensors. During a study of the plethysmographic wave forms from various sites (finger, ear, and forehead) it was noted that in some cases the forehead wave form became unexpectedly complex in configuration. The plethysmographic signals from 25 general anesthetic cases were obtained, which revealed the complex forehead wave form during 5 cases. We hypothesized that the complex wave form was attributable to an underlying venous signal. It was determined that the use of a pressure dressing over the sensor resulted in a return of a normal plethysmographic wave form. Further examination of the complex forehead wave form reveal a morphology consistent with a central venous trace with atrial, cuspidal, and venous waves. It is speculated that the presence of the venous signal is the source of the problems reported with the forehead sensors. It is believed that the venous wave form is a result of the method of attachment rather than the use of reflective plethysmographic sensors.

  7. Longitudinal fasting blood glucose patterns and arterial stiffness risk in a population without diabetes.

    Science.gov (United States)

    Wu, Yuntao; Yu, Junxing; Jin, Cheng; Li, Yun; Su, Jinmei; Wei, Guoqing; Zheng, Xiaoming; Gao, Jingsheng; Gao, Wenyuan; Wu, Shouling

    2017-01-01

    To identify long-term fasting blood glucose trajectories and to assess the association between the trajectories and the risk of arterial stiffness in individuals without diabetes. We enrolled 16,454 non-diabetic participants from Kailuan cohort. Fasting blood glucose concentrations were measured in 2006, 2008, and 2010 survey. Brachial-ankle pulse wave velocities were measured during 2011 to 2016. Multivariate regression model was used to estimate the difference of brachial-ankle pulse wave velocity levels and logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (95%CIs) of arterial stiffness risk, according to the fasting blood glucose trajectories. We identified five distinct fasting blood glucose trajectories and each of the trajectories was labeled according to its range and change over 2006-2010 survey: elevated-stable pattern (5.0% of participants), elevated-decreasing pattern (6.6%), moderate-increasing pattern (10.9%), moderate-stable pattern (59.3%), and low-stable pattern (18.2%). After adjustment for potential confounders, individuals with elevated-stable pattern had a 42.6 cm/s (95%CI: 24.7 to 60.6 cm/s) higher brachial-ankle pulse wave velocity level and a 37% (OR 1.37, 95%CI: 1.14 to 1.66) higher arterial stiffness risk, and individuals with moderate-increasing pattern had a 19.6 cm/s (95%CI: 6.9 to 32.3 cm/s) higher brachial-ankle pulse wave velocity level and a 17% (OR 1.17, 95%CI: 1.03 to 1.33) higher arterial stiffness risk, related to individuals with moderate-stable pattern. We did not find significant associations of the elevated-decreasing or low-stable patterns with arterial stiffness. Consistently, the cumulative average, variability, and increased rate of fasting blood glucose during 2006-2010 survey were significantly associated with the arterial stiffness risk. Discrete fasting blood glucose trajectories were associated with the arterial stiffness risk in non-diabetic individuals.

  8. Free-weight resistance exercise on pulse wave reflection and arterial stiffness between sexes in young, resistance-trained adults.

    Science.gov (United States)

    Kingsley, J Derek; Tai, Yu Lun; Mayo, Xian; Glasgow, Alaina; Marshall, Erica

    2017-09-01

    We sought to determine the sex-specific effects of an acute bout of free-weight resistance exercise (RE) on pulse wave reflection (aortic blood pressures, augmentation index (AIx), AIx at 75 bpm (AIx@75), augmentation pressure (AP), time of the reflected wave (Tr), subendocardial viability ratio (SEVR)), and aortic arterial stiffness in resistance-trained individuals. Resistance-trained men (n = 14) and women (n = 12) volunteered to participate in the study. Measurements were taken in the supine position at rest, and 10 minutes after 3 sets of 10 repetitions at 75% 1-repetition maximum on the squat, bench press, and deadlift. A 2 × 2 × 2 ANOVA was used to analyse the effects of sex (men, women) across condition (RE, control) and time (rest, recovery). There were no differences between sexes across conditions and time. There was no effect of the RE on brachial or aortic blood pressures. There were significant condition × time interactions for AIx (rest: 12.1 ± 7.9%; recovery: 19.9 ± 10.5%, p = .003), AIx@75 (rest: 5.3 ± 7.9%; recovery: 24.5 ± 14.3%, p = .0001), AP (rest: 4.9 ± 2.8 mmHg; recovery: 8.3 ± 6.0 mmHg, p = .004), and aortic arterial stiffness (rest: 5.3 ± 0.6 ms; recovery: 5.9 ± 0.7 ms, p = .02) with significant increases during recovery from the acute RE. There was also a significant condition × time for time of the reflected wave (rest: 150 ± 7 ms; recovery: 147 ± 9 ms, p = .02) and SEVR (rest: 147 ± 17%; recovery: 83 ± 24%, p = .0001) such that they were reduced during recovery from the acute RE compared to the control. These data suggest that an acute bout of RE increases AIx, AIx@75, and aortic arterial stiffness similarly between men and women without significantly altering aortic blood pressures.

  9. 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.

  10. Extensional flow of low-viscosity fluids in capillary bridges formed by pulsed surface acoustic wave jetting

    International Nuclear Information System (INIS)

    Bhattacharjee, P K; McDonnell, A G; Prabhakar, R; Yeo, L Y; Friend, J

    2011-01-01

    Forming capillary bridges of low-viscosity (∼<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.

  11. Determination of testicular blood flow in camelids using vascular casting and color pulsed-wave Doppler ultrasonography.

    Science.gov (United States)

    Kutzler, Michelle; Tyson, Reid; Grimes, Monica; Timm, Karen

    2011-01-01

    We describe the vasculature of the camelid testis using plastic casting. We also use color pulsed-wave Doppler ultrasonography to measure testicular blood flow and compare the differences between testicular blood flow in fertile and infertile camelids. The testicular artery originates from the ventral surface of the aorta, gives rise to an epididymal branch, and becomes very tortuous as it approaches the testis. Within the supratesticular arteries, peak systolic velocity (PSV) was higher in fertile males compared to infertile males (P = 0.0004). In addition, end diastolic velocity (EDV) within the supratesticular arteries was higher for fertile males when compared to infertile males (P = 0.0325). Within the marginal arteries, PSV was also higher in fertile males compared to infertile males (P = 0.0104). However, EDV within the marginal arteries was not significantly different between fertile and infertile males (P = 0.121). In addition, the resistance index was not significantly different between fertile and infertile males within the supratesticular (P = 0.486) and marginal arteries (P = 0.144). The significance of this research is that in addition to information obtained from a complete reproductive evaluation, a male camelid's fertility can be determined using testicular blood flow measured by Doppler ultrasonography.

  12. The effect of workplace smoking bans on heart rate variability and pulse wave velocity of non-smoking hospitality workers.

    Science.gov (United States)

    Rajkumar, Sarah; Schmidt-Trucksäss, Arno; Wellenius, Gregory A; Bauer, Georg F; Huynh, Cong Khanh; Moeller, Alexander; Röösli, Martin

    2014-08-01

    To investigate the effect of a change in second-hand smoke (SHS) exposure on heart rate variability (HRV) and pulse wave velocity (PWV), this study utilized a quasi-experimental setting when a smoking ban was introduced. HRV, a quantitative marker of autonomic activity of the nervous system, and PWV, a marker of arterial stiffness, were measured in 55 non-smoking hospitality workers before and 3-12 months after a smoking ban and compared to a control group that did not experience an exposure change. SHS exposure was determined with a nicotine-specific badge and expressed as inhaled cigarette equivalents per day (CE/d). PWV and HRV parameters significantly changed in a dose-dependent manner in the intervention group as compared to the control group. A one CE/d decrease was associated with a 2.3% (95% CI 0.2-4.4; p = 0.031) higher root mean square of successive differences (RMSSD), a 5.7% (95% CI 0.9-10.2; p = 0.02) higher high-frequency component and a 0.72% (95% CI 0.40-1.05; p < 0.001) lower PWV. PWV and HRV significantly improved after introducing smoke-free workplaces indicating a decreased cardiovascular risk.

  13. A comparative study of the plasmon effect in nanoelectrode THz emitters: Pulse vs. continuous-wave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Kiwon; Lee, Eui Su; Lee, Il-Min; Han, Sang-Pil; Kim, Hyun-Soo; Park, Kyung Hyun, E-mail: khp@etri.re.kr [Terahertz Basic Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700 (Korea, Republic of); Choi, Jeongyong [Metal-Insulator Transition Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700 (Korea, Republic of); Lee, Donghun [Optical Internet Components Research Section, Electronics and Telecommunications Research Institute (ETRI), Daejeon 305-700 (Korea, Republic of)

    2016-08-15

    Plasmonic field enhancement in terahertz (THz) generation is one of the recently arisen techniques in the THz field that has attracted considerable interest. However, the reported levels of enhancement of THz output power in the literature are significantly different from each other, from less than two times to about two orders of magnitude of enhancement in power, which implies the existence of other major limiting factors yet to be revealed. In this work, the contribution of the plasmonic effect to the power enhancement of THz emitters is revisited. We show that the carrier collection efficiency in a THz emitter with plasmonic nanostructures is more critical to the device performance than the plasmonic field enhancement itself. The strong reverse fields induced by the highly localized plasmonic carriers in the vicinity of the nanoelectrodes screen the carrier collections and seriously limit the power enhancement. This is supported by our experimental observations of the significantly enhanced power in a plasmonic nanoelectrode THz emitter in continuous-wave radiation mode, while the same device has limited enhancement with pulsed radiation. We hope that our study may provide an intuitive but practical guideline in adopting plasmonic nanostructures with an aim of enhancing the efficiency of optoelectronic devices.

  14. PMN-PT single crystal, high-frequency ultrasonic needle transducers for pulsed-wave Doppler application.

    Science.gov (United States)

    Zhou, Qifa; Xu, Xiaochen; Gottlieb, Emanuel J; Sun, Lei; Cannata, Jonathan M; Ameri, Hossein; Humayun, Mark S; Han, Pengdi; Shung, K Kirk

    2007-03-01

    High-frequency needle ultrasound transducers with an aperture size of 0.4 mm were fabricated using lead magnesium niobate-lead titanate (PMN-33% PT) as the active piezoelectric material. The active element was bonded to a conductive silver particle matching layer and a conductive epoxy backing through direct contact curing. An outer matching layer of parylene was formed by vapor deposition. The active element was housed within a polyimide tube and a 20-gauge needle housing. The magnitude and phase of the electrical impedance of the transducer were 47 omega and -38 degrees, respectively. The measured center frequency and -6 dB fractional bandwidth of the PMN-PT needle transducer were 44 MHz and 45%, respectively. The two-way insertion loss was approximately 15 dB. In vivo high-frequency, pulsed-wave Doppler patterns of blood flow in the posterior portion and in vitro ultrasonic backscatter microscope (UBM) images of the rabbit eye were obtained with the 44-MHz needle transducer.

  15. Determination of Testicular Blood Flow in Camelids Using Vascular Casting and Color Pulsed-Wave Doppler Ultrasonography

    Directory of Open Access Journals (Sweden)

    Michelle Kutzler

    2011-01-01

    Full Text Available We describe the vasculature of the camelid testis using plastic casting. We also use color pulsed-wave Doppler ultrasonography to measure testicular blood flow and compare the differences between testicular blood flow in fertile and infertile camelids. The testicular artery originates from the ventral surface of the aorta, gives rise to an epididymal branch, and becomes very tortuous as it approaches the testis. Within the supratesticular arteries, peak systolic velocity (PSV was higher in fertile males compared to infertile males (P=0.0004. In addition, end diastolic velocity (EDV within the supratesticular arteries was higher for fertile males when compared to infertile males (P=0.0325. Within the marginal arteries, PSV was also higher in fertile males compared to infertile males (P=0.0104. However, EDV within the marginal arteries was not significantly different between fertile and infertile males (P=0.121. In addition, the resistance index was not significantly different between fertile and infertile males within the supratesticular (P=0.486 and marginal arteries (P=0.144. The significance of this research is that in addition to information obtained from a complete reproductive evaluation, a male camelid's fertility can be determined using testicular blood flow measured by Doppler ultrasonography.

  16. High-frequency dual mode pulsed wave Doppler imaging for monitoring the functional regeneration of adult zebrafish hearts

    Science.gov (United States)

    Kang, Bong Jin; Park, Jinhyoung; Kim, Jieun; Kim, Hyung Ham; Lee, Changyang; Hwang, Jae Youn; Lien, Ching-Ling; Shung, K. Kirk

    2015-01-01

    Adult zebrafish is a well-known small animal model for studying heart regeneration. Although the regeneration of scars made by resecting the ventricular apex has been visualized with histological methods, there is no adequate imaging tool for tracking the functional recovery of the damaged heart. For this reason, high-frequency Doppler echocardiography using dual mode pulsed wave Doppler, which provides both tissue Doppler (TD) and Doppler flow in a same cardiac cycle, is developed with a 30 MHz high-frequency array ultrasound imaging system. Phantom studies show that the Doppler flow mode of the dual mode is capable of measuring the flow velocity from 0.1 to 15 cm s−1 with high accuracy (p-value = 0.974 > 0.05). In the in vivo study of zebrafish, both TD and Doppler flow signals were simultaneously obtained from the zebrafish heart for the first time, and the synchronized valve motions with the blood flow signals were identified. In the longitudinal study on the zebrafish heart regeneration, the parameters for diagnosing the diastolic dysfunction, for example, E/Em < 10, E/A < 0.14 for wild-type zebrafish, were measured, and the type of diastolic dysfunction caused by the amputation was found to be similar to the restrictive filling. The diastolic function was fully recovered within four weeks post-amputation. PMID:25505135

  17. LDL-oxidation, serum uric acid, kidney function and pulse-wave velocity: Data from the Brisighella Heart Study cohort.

    Science.gov (United States)

    Cicero, Arrigo F G; Kuwabara, Masanari; Johnson, Richard; Bove, Marilisa; Fogacci, Federica; Rosticci, Martina; Giovannini, Marina; D'Addato, Sergio; Borghi, Claudio

    2018-06-15

    Serum uric acid (SUA) and oxidized LDL (oxLDL) may be associated with arterial aging. The aim of our study was to evaluate the relationship between SUA, oxLDL and arterial stiffness in subjects with normal renal function and in patients with mild or moderate renal impairment. From the database of the 2012 Brisighella Heart Study, we compared age-matched adult, non-smoker subjects without cardiovascular disease and with normal renal function (n = 205), subjects with stage II chronic kidney disease (CKD) (n = 118) and subjects with stage III CKD (n = 94). All subjects underwent a determination of the LDL oxidative susceptibility, oxLDL levels, SUA and Pulse Wave Velocity (PWV). By univariate analysis, PWV correlated with a large number of clinical, haemodynamic and metabolic parameters, including estimated glomerular filtration rate (eGFR) in subjects with normal renal function and in those with stage II or III CKD. Stepwise multiple regression analyses showed that in the presence of normal renal function or stage II CKD, the main predictors of PWV were age, systolic blood pressure (SBP), ox-LDL, apolipoprotein B and SUA (p function, but not in the subjects with more compromised eGFR. This study confirms the complex relationship of SUA with cardiovascular and metabolic disease in the patient with established renal disease. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Effect of physical activity on pulse wave velocity in elderly subjects with normal glucose, prediabetes or Type 2 Diabetes.

    Science.gov (United States)

    Metsämarttila, Erja; Rodilla, Enrique; Jokelainen, Jari; Herrala, Sauli; Leppäluoto, Juhani; Keinänen-Kiukaanniemi, Sirkka; Herzig, Karl-Heinz

    2018-05-23

    Carotid-femoral pulse wave velocity ((cf)PWV) is a measure of arterial stiffness, predicting cardiovascular disease. We hypothesized that the amount of physical activity (PA) is correlated with reduced arterial stiffness in Type 2 diabetic (T2D) subjects. 570 subjects from the 1945 Oulu birth cohort were included in the analysis. (cf)PWV was determined by a non-invasive applanation tonometry. Oral glucose tolerance test was performed and LDL and HDL cholesterol analyzed. PA was registered daily with a wrist-worn acceleration meter for two weeks. (cf)PWV values in subjects with impaired glucose metabolism (IGM) and T2D were higher than in normal glycemic subjects (P < 0.001). PA, fasting and 2 h glucose and HbA1c correlated significantly with (cf)PWV, but HDL or LDL cholesterol did not. The 2 h glucose, heart rate and alcohol consumption in T2D subjects had independent effects on (cf)PWV in multiple regression analysis. T2D and IGM were significantly associated to (cf)PWV. Interestingly, lipids did not have an additional effect on (cf)PWV. Subjects walking more than 10 000 steps/day had 0.2 m/s lower (cf)PWV than those walking less than 6000 steps/day. Presence of T2D, elevated heart rate and alcohol consumption in males were associated with increased aortic stiffening in elderly subjects.

  19. 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

    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 with...... by using large-aperture crystals. The technique can readily be implemented with other crystals and laser wavelengths, and can therefore potentially replace current ultrafast frequency-conversion processes to the mid-IR....... 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...

  20. Theoretical and experimental investigation of the Z pinch plasma as a source of power pulse of soft X radiation for generation of shock waves in condensed targets

    International Nuclear Information System (INIS)

    Grabovskij, E.V.; Smirnov, V.P.; Zakharov, S.V.; Vorob'ev, O.Yu.; Dyabilin, K.S.; Lebedev, M.E.; Fortov, V.E.; Frolov, A.A.

    1996-01-01

    Paper presents the results of theoretical analysis of processes occurring in Z-pinch plasma under conditions initiating a powerful pulse of soft X-radiation. The main attention is focused on double liner circuit designs. Estimations of power of radiation and spectrum are studied. The results are used to simulate processes occurring at generation of shock waves under the effect of soft X-radiation on the target. Experiments to generate shock waves with up to 3 Mbar amplitude pressure in lead under the effect of soft X-radiation were conducted using Angara-5 plant. 24 refs., 9 figs

  1. Kidney transplantation improves arterial function measured by pulse wave analysis and endothelium-independent dilatation in uraemic patients despite deterioration of glucose metabolism

    DEFF Research Database (Denmark)

    Hornum, Mads; Clausen, Peter; Idorn, Thomas

    2011-01-01

    for kidney transplantation (uraemic control group, age 47 ± 11 years). Arterial function was estimated by the pulse wave velocity (PWV) of the carotid-femoral pulse wave, aortic augmentation index (AIX), flow-mediated (FMD) and nitroglycerin-induced vasodilatation (NID) of the brachial artery performed......BACKGROUND: The aim of this study is to investigate the effect of kidney transplantation on arterial function in relation to changes in glucose metabolism. METHODS: Included were 40 kidney recipients (Tx group, age 38 ± 13 years) and 40 patients without known diabetes remaining on the waiting list...... before transplantation and after 12 months. PWV recorded sequentially at the carotid and femoral artery is an estimate of arterial stiffness; AIX is an integrated index of vascular and ventricular function. FMD and NID are the dilatory capacities of the brachial artery after increased flow (endothelium...

  2. SIMULATION OF FORWARD AND BACKWARD WAVES EVOLUTION OF FEW-CYCLE PULSES PROPAGATING IN AN OPTICAL WAVEGUIDE WITH DISPERSION AND CUBIC NONLINEARITY OF ELECTRONIC AND ELECTRONIC-VIBRATION NATURE

    Directory of Open Access Journals (Sweden)

    L. S. Konev

    2015-09-01

    Full Text Available Numerical method for calculation of forward and backward waves of intense few-cycle laser pulses propagating in an optical waveguide with dispersion and cubic nonlinearity of electronic and electronic-vibration nature is described. Simulations made with the implemented algorithm show that accounting for Raman nonlinearity does not lead to qualitative changes in behavior of the backward wave. Speaking about quantitative changes, the increase of efficiency of energy transfer from the forward wave to the backward wave is observed. Presented method can be also used to simulate interaction of counterpropagating pulses.

  3. 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.

  4. Identifying Coronary Artery Disease in Asymptomatic Middle-Aged Sportsmen: The Additional Value of Pulse Wave Velocity.

    Directory of Open Access Journals (Sweden)

    Thijs L Braber

    Full Text Available Cardiovascular screening may benefit middle-aged sportsmen, as coronary artery disease (CAD is the main cause of exercise-related sudden cardiac death. Arterial stiffness, as measured by pulse wave velocity (PWV, may help identify sportsmen with subclinical CAD. We examined the additional value of PWV measurements to traditional CAD risk factors for identifying CAD.From the Measuring Athlete's Risk of Cardiovascular events (MARC cohort of asymptomatic, middle-aged sportsmen who underwent low-dose Cardiac CT (CCT after routine sports medical examination (SME, 193 consecutive sportsmen (aged 55 ± 6.6 years were included with additional PWV measurements before CCT. Sensitivity, specificity and predictive values of PWV values (>8.3 and >7.5 m/s assessed by Arteriograph were used to identify CAD (coronary artery calcium scoring ≥ 100 Agatston Units or coronary CT angiography luminal stenosis ≥ 50% and to assess the additional diagnostic value of PWV to established cardiovascular risk factors.Forty-seven sportsmen (24% had CAD on CCT. They were older (58.9 vs. 53.8 years, p8.3m/s respectively >7.5 m/s sensitivity to detect CAD on CT was 43% and 74%, specificity 69% and 45%, positive predictive value 31% and 30%, and negative predictive value 79% and 84%. Adding PWV to traditional risk factor models did not change the area under the curve (from 0.78 (95% CI = 0.709-0.848 to AUC 0.78 (95% CI 0.710-0.848, p = 0.99 for prediction of CAD on CCT.Limited additional value was found for PWV on top of established risk factors to identify CAD. PWV might still have a role to identify CAD in middle-aged sportsmen if risk factors such as cholesterol are unknown.

  5. Aortic-Brachial Pulse Wave Velocity Ratio: A Measure of Arterial Stiffness Gradient Not Affected by Mean Arterial Pressure.

    Science.gov (United States)

    Fortier, Catherine; Desjardins, Marie-Pier; Agharazii, Mohsen

    2018-03-01

    Aortic stiffness, measured by carotid-femoral pulse wave velocity (cf-PWV), is used for the prediction of cardiovascular risk. This mini-review describes the nonlinear relationship between cf-PWV and operational blood pressure, presents the proposed methods to adjust for this relationship, and discusses a potential place for aortic-brachial PWV ratio (a measure of arterial stiffness gradient) as a blood pressure-independent measure of vascular aging. PWV is inherently dependent on the operational blood pressure. In cross-sectional studies, PWV adjustment for mean arterial pressure (MAP) is preferred, but still remains a nonoptimal approach, as the relationship between PWV and blood pressure is nonlinear and varies considerably among individuals due to heterogeneity in genetic background, vascular tone, and vascular remodeling. Extrapolations from the blood pressure-independent stiffness parameter β (β 0 ) have led to the creation of stiffness index β, which can be used for local stiffness. A similar approach has been used for cardio-ankle PWV to generate a blood pressure-independent cardio-ankle vascular index (CAVI). It was recently demonstrated that stiffness index β and CAVI remain slightly blood pressure-dependent, and a more appropriate formula has been proposed to make the proper adjustments. On the other hand, the negative impact of aortic stiffness on clinical outcomes is thought to be mediated through attenuation or reversal of the arterial stiffness gradient, which can also be influenced by a reduction in peripheral medium-sized muscular arteries in conditions that predispose to accelerate vascular aging. Arterial stiffness gradient, assessed by aortic-brachial PWV ratio, is emerging to be at least as good as cf-PWV for risk prediction, but has the advantage of not being affected by operating MAP. The negative impacts of aortic stiffness on clinical outcomes are proposed to be mediated through attenuation or reversal of arterial stiffness gradient

  6. A comparative study of the effect of coronary atherosclerosis and age on aortic and pulmonary arterial pulse wave velocity

    International Nuclear Information System (INIS)

    Hanya, Shizuo

    2008-01-01

    The effect of coronary artery disease (CAD) and age on aortic (AO-PWV) and pulmonary arterial pulse wave velocity (PA-PWV) was studied. Aortic and pulmonary arterial pressure were measured at two sites (ascending and abdominal aorta, and the main pulmonary trunk and one of its principle branches, respectively) using a catheter-tip micromanometer in 24 patients divided in two groups. Control group (n=12) consisted of patients with normal coronaries, while the CAD group (n=12) consisted of patients with coronary artery disease estimated by coronary angiography. The interval between these two sites was determined by measuring the withdrawal distance of the microtip-catheter. AO-PWV was significantly higher (p<0.02) in the CAD group (12.0±4.1 m/sec) than in the control group (8.2±2.7 m/sec). There was no significant difference between the two groups in PA-PWV. AO-PWV was significantly (r=0.731, p<0.01) increased with age in the control group, while no significant correlation between the two was observed in the CAD group. There was no significant correlation between PA-PWV and age in control group. The results of this study indicate that only coronary atherosclerosis and age have significant predictive value regarding AO-PWV, but there was no significant correlation with PA-PWV for any of these parameters. The PA-PWV invasively measured in the 12 control subjects in this study was 2.3±0.7 m/sec, which is very close to values reported in the recent literatures using MRI. (author)

  7. Effect of carbohydrate restriction-induced weight loss on aortic pulse wave velocity in overweight men and women.

    Science.gov (United States)

    Syed-Abdul, Majid M; Hu, Qiong; Jacome-Sosa, Miriam; Padilla, Jaume; Manrique-Acevedo, Camila; Heimowitz, Colette; Parks, Elizabeth J

    2018-05-10

    Increased aortic stiffness, measured by carotid-to-femoral pulse wave velocity (PWV), is an independent predictor of cardiovascular disease (CVD) and past data have shown that low-fat and low-energy diets, fed for 8-24 wks lower PWV. The purpose of this study was to determine whether a reduction in PWV would be achieved by dietary carbohydrate (CHO) restriction, shown to bring about weight loss over a shorter timeframe. Men [n=10, age: 41.8 ± 3.2 y, BMI: 34.2 ± 1.0 kg/m2 (mean±SE)] and women (n=10, age: 38.6 ± 1.9 y, BMI: 33.5 ± 1.2 kg/m2) with characteristics of insulin resistance and the metabolic syndrome, consumed a structured, CHO-restricted diet (CRD) for 4 wks (energy deficit, 645 kcal/d). For the whole group, subjects lost 5.4 ± 0.5 % (Pwomen, it fell significantly (from 7.2 ± 0.3 m/s to 6.3 ± 0.3 m/s, P=0.028), while no changes were observed in men (7.2 ± 0.3 vs 7.0 ± 0.3 m/s, P=0.144). This is the first study to demonstrate that weight loss can improve PWV in as little as 4 wks and that dietary CHO restriction may be an effective treatment for reducing aortic stiffness in women. Future studies are needed to establish the mechanisms by which dietary CHO restriction may confer more cardiovascular benefits to women compared to men.

  8. Considerations for SphygmoCor radial artery pulse wave analysis: side selection and peripheral arterial blood pressure calibration.

    Science.gov (United States)

    Martin, Jeffrey S; Borges, Alexandra R; Christy, John B; Beck, Darren T

    2015-10-01

    Methods employed for pulse wave analysis (PWA) and peripheral blood pressure (PBP) calibration vary. The purpose of this study was to evaluate the agreement of SphygmoCor PWA parameters derived from radial artery tonometry when considering (1) timing (before vs. after tonometry) and side selection (ipsilateral vs. contralateral limb) for PBP calibration and (2) side selection for tonometry (left vs. right arm). In 34 subjects (aged 21.9 ± 2.3 years), bilateral radial artery tonometry was performed simultaneously on three instances. PBP assessment via oscillometric sphygmomanometry in the left arm only and both arms simultaneously occurred following the first and second instances of tonometry, respectively. Significant within arm differences in PWA parameters derived before and after PBP measurement were observed in the right arm only (for example, aortic systolic blood pressure, Δ=0.38 ± 0.64 mm Hg). Simultaneously captured bilateral PWA variables demonstrated significant between arm differences in 88% (14/16) and 56% (9/16) of outcome variables when calibrated to within arm and equivalent PBP, respectively. Moreover, the right arm consistently demonstrated lower values for clinical PWA variables (for example, augmentation index, bias=-2.79%). However, 26% (n=9) of participants presented with clinically significant differences (>10 mm Hg) in bilateral PBP and their exclusion from analysis abolished most between arm differences observed. SphygmoCor PWA in the right radial artery results in greater variability independent of the timing of PBP measurement and magnitude of calibration pressures in young subjects. Moreover, bilateral PBP measurement is imperative to identify subjects in whom a significant difference in bilateral PWA outcomes may exist.

  9. High C reactive protein associated with increased pulse wave velocity among urban men with metabolic syndrome in Malaysia.

    Science.gov (United States)

    Aminuddin, Amilia; Zakaria, Zaiton; Fuad, Ahmad F; Kamsiah, Jaarin; Othman, Faizah; Das, Srijit; Kamisah, Yusof; Qodriyah, Haji S; Jubri, Zakiah; Nordin, Nor Anita M; Ngah, Wan Z

    2013-03-01

    To determine the association between carotid femoral pulse wave velocity (PWVCF); augmentation index (AI); and high-sensitivity C reactive protein (hs-CRP) with metabolic syndrome (MetS), and to determine the influence of ethnicity on PWVCF and AI, and the association between high hs-CRP and increased PWV, and AI in MetS. A cross-sectional study was conducted at Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia from September 2009 to September 2011. Three hundred and eighty men (Chinese and Malays) were recruited from the study. The PWVCF and AI were measured by Vicorder (SMT Medical, Wuerzburg, Germany). The hs-CRP level was also determined. We defined MetS using the International Diabetes Federation (IDF) and harmonized criteria. Malays had higher AI compared to the Malaysian Chinese. Patients with MetS had higher PWVCF (IDF criteria: 8.5 [8.3-8.7] versus 8.2 [8.0-8.4] m/s, p=0.03; harmonized criteria: 8.5 [8.4-8.7] versus 8.2 [8.0-8.4] m/s, p=0.007) and hs-CRP (IDF criteria: 0.9+/-2.0 versus 0.4+/-1.1 mg/L, p=0.0007; harmonized criteria: 0.8+/-1.9 versus 0.4+/-1.1 mg/L, p=0.002) compared to non-MetS. In subjects with MetS, those with high hs-CRP (>3 mg/L) had higher PWVCF. Augmentation index values were significantly higher in Malays compared with Malaysian Chinese. Metabolic syndrome was associated with increased PWVCF and hs-CRP. Patients with MetS and high hs-CRP were associated with higher PWVCF. The measurement of hs-CRP reflects the degree of subclinical vascular damage in MetS.

  10. Observation of sum-frequency-generation-induced cascaded four-wave mixing using two crossing femtosecond laser pulses in a 0.1 mm beta-barium-borate crystal.

    Science.gov (United States)

    Liu, Weimin; Zhu, Liangdong; Fang, Chong

    2012-09-15

    We demonstrate the simultaneous generation of multicolor femtosecond laser pulses spanning the wavelength range from UV to near IR in a 0.1 mm Type I beta-barium borate crystal from 800 nm fundamental and weak IR super-continuum white light (SCWL) pulses. The multicolor broadband laser pulses observed are attributed to two concomitant cascaded four-wave mixing (CFWM) processes as corroborated by calculation: (1) directly from the two incident laser pulses; (2) by the sum-frequency generation (SFG) induced CFWM process (SFGFWM). The latter signal arises from the interaction between the frequency-doubled fundamental pulse (400 nm) and the SFG pulse generated in between the fundamental and IR-SCWL pulses. The versatility and simplicity of this spatially dispersed multicolor self-compressed laser pulse generation offer compact and attractive methods to conduct femtosecond stimulated Raman spectroscopy and time-resolved multicolor spectroscopy.

  11. Laser-Bioplasma Interaction: Excitation and Suppression of the Brain Waves by the Multi-photon Pulsed-operated Fiber Lasers in the Ultraviolet Range of Frequencies

    Science.gov (United States)

    Stefan, V. Alexander; IAPS-team Team

    2017-10-01

    The novel study of the laser excitation-suppression of the brain waves is proposed. It is based on the pulsed-operated multi-photon fiber-laser interaction with the brain parvalbumin (PV) neurons. The repetition frequency matches the low frequency brain waves (5-100 Hz); enabling the resonance-scanning of the wide range of the PV neurons (the generators of the brain wave activity). The tunable fiber laser frequencies are in the ultraviolet frequency range, thus enabling the monitoring of the PV neuron-DNA, within the 10s of milliseconds. In medicine, the method can be used as an ``instantaneous-on-off anesthetic.'' Supported by Nikola Tesla Labs, Stefan University.

  12. BRIEF COMMUNICATIONS: Strong reflection of a series of pulses from a four-wave mirror with thermal nonlinearity under parametric feedback conditions

    Science.gov (United States)

    Barashkov, M. S.; Bel'dyugin, Igor'M.; Zolotarev, M. V.; Kruzhilin, Yu I.; Krymskiĭ, M. I.; Oshkin, S. P.; Starkov, G. S.; Umnov, A. F.; Kharchenko, M. A.

    1989-04-01

    A four-wave mirror exhibiting a thermal nonlinearity was used in a study of the interaction of concurrent waves under parametric feedback conditions in the presence of a nonreciprocal element. Strong reflection of a series of pulses of ~ 300 ns duration from a neodymium glass laser was demonstrated: the maximum reflection coefficient was in excess of 30. An analysis was made of the quality of the radiation reflected from this four-mirror parametric feedback system. A considerable reduction was observed in the steady-state threshold for the operation of this mirror with a thermal nonlinearity when the angles of convergence of the interacting beams were small compared with the case of head-on collision of the waves.

  13. 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)

    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 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.)

  14. 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.)

  15. Unified model of plasma formation, bubble generation and shock wave emission in water for fs to ns laser pulses (Conference Presentation)

    Science.gov (United States)

    Liang, Xiao-Xuan; Freidank, Sebastian; Linz, Norbert; Paltauf, Günther; Zhang, Zhenxi; Vogel, Alfred

    2017-03-01

    We developed modeling tools for optical breakdown events in water that span various phases reaching from breakdown initiation via solvated electron generation, through laser induced-plasma formation and temperature evolution in the focal spot to the later phases of cavitation bubble dynamics and shock wave emission and applied them to a large parameter space of pulse durations, wavelengths, and pulse energies. The rate equation model considers the interplay of linear absorption, photoionization, avalanche ionization and recombination, traces thermalization and temperature evolution during the laser pulse, and portrays the role of thermal ionization that becomes relevant for T > 3000 K. Modeling of free-electron generation includes recent insights on breakdown initiation in water via multiphoton excitation of valence band electrons into a solvated state at Eini = 6.6 eV followed by up-conversion into the conduction band level that is located at 9.5 eV. The ability of tracing the temperature evolution enabled us to link the model of laser-induced plasma formation with a hydrodynamic model of plasma-induced pressure evolution and phase transitions that, in turn, traces bubble generation and dynamics as well as shock wave emission. This way, the amount of nonlinear energy deposition in transparent dielectrics and the resulting material modifications can be assessed as a function of incident laser energy. The unified model of plasma formation and bubble dynamics yields an excellent agreement with experimental results over the entire range of investigated pulse durations (femtosecond to nanosecond), wavelengths (UV to IR) and pulse energies.

  16. 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.

  17. 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.

  18. Comparison of the Complior Analyse device with Sphygmocor and Complior SP for pulse wave velocity and central pressure assessment.

    Science.gov (United States)

    Stea, Francesco; Bozec, Erwan; Millasseau, Sandrine; Khettab, Hakim; Boutouyrie, Pierre; Laurent, Stéphane

    2014-04-01

    The Complior device (Alam Medical, France) was used in epidemiological studies which established pulse wave velocity (PWV) as a cardiovascular risk marker. Central pressure is related, but complementary to PWV and also associated to cardiovascular outcomes. The new Complior Analyse measures both PWV and central blood pressure during the same acquisition. The aim of this study was to compare PWV values from Complior Analyse with the previous Complior SP (PWVcs) and with Sphygmocor (PWVscr; AtCor, Australia), and to compare central systolic pressure from Complior Analyse and Sphygmocor. Peripheral and central pressures and PWV were measured with the three devices in 112 patients. PWV measurements from Complior Analyse were analysed using two foot-detection algorithms (PWVca_it and PWVca_cs). Both radial (ao-SBPscr) and carotid (car-SBPscr) approaches from Sphygmocor were compared to carotid Complior Analyse measurements (car-SBPca). The same distance and same calibrating pressures were used for all devices. PWVca_it was strongly correlated to PWVscr (R(2) = 0.93, P < 0.001) with a difference of 0.0 ± 0.7  m/s. PWVca_cs was also correlated to PWVcs (R(2) = 0.90, P < 0.001) with a difference of 0.1 ± 0.7  m/s. Central systolic pressures were strongly correlated. The difference between car-SBPca and ao-SBPscr was 3.1 ± 4.2  mmHg (P < 0.001), statistically equivalent to the difference between car-SBPscr and ao-SBPscr (3.9 ± 5.8  mmHg, P < 0.001), whilst the difference between car-SBPca and car-SBPscr was negligible (-0.7 ± 5.6  mmHg, P = NS). The new Complior Analyse device provides equivalent results for PWV and central pressure values to the Sphygmocor and Complior SP. It reaches Association for the Advancement of Medical Instrumentation standard for central blood pressure and grades as excellent for PWV on the Artery Society criteria. It can be interchanged with existing devices.

  19. A sensitivity analysis of a personalized pulse wave propagation model for arteriovenous fistula surgery. Part B: Identification of possible generic model parameters.

    Science.gov (United States)

    Huberts, W; de Jonge, C; van der Linden, W P M; Inda, M A; Passera, K; Tordoir, J H M; van de Vosse, F N; Bosboom, E M H

    2013-06-01

    Decision-making in vascular access surgery for hemodialysis can be supported by a pulse wave propagation model that is able to simulate pressure and flow changes induced by the creation of a vascular access. To personalize such a model, patient-specific input parameters should be chosen. However, the number of input parameters that can be measured in clinical routine is limited. Besides, patient data are compromised with uncertainty. Incomplete and uncertain input data will result in uncertainties in model predictions. In part A, we analyzed how the measurement uncertainty in the input propagates to the model output by means of a sensitivity analysis. Of all 73 input parameters, 16 parameters were identified to be worthwhile to measure more accurately and 51 could be fixed within their measurement uncertainty range, but these latter parameters still needed to be measured. Here, we present a methodology for assessing the model input parameters that can be taken constant and therefore do not need to be measured. In addition, a method to determine the value of this parameter is presented. For the pulse wave propagation model applied to vascular access surgery, six patient-specific datasets were analyzed and it was found that 47 out of 73 parameters can be fixed on a generic value. These model parameters are not important for personalization of the wave propagation model. Furthermore, we were able to determine a generic value for 37 of the 47 fixable model parameters. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. Finite element method (FEM) model of the mechanical stress on phospholipid membranes from shock waves produced in nanosecond electric pulses (nsEP)

    Science.gov (United States)

    Barnes, Ronald; Roth, Caleb C.; Shadaram, Mehdi; Beier, Hope; Ibey, Bennett L.

    2015-03-01

    The underlying mechanism(s) responsible for nanoporation of phospholipid membranes by nanosecond pulsed electric fields (nsEP) remains unknown. The passage of a high electric field through a conductive medium creates two primary contributing factors that may induce poration: the electric field interaction at the membrane and the shockwave produced from electrostriction of a polar submersion medium exposed to an electric field. Previous work has focused on the electric field interaction at the cell membrane, through such models as the transport lattice method. Our objective is to model the shock wave cell membrane interaction induced from the density perturbation formed at the rising edge of a high voltage pulse in a polar liquid resulting in a shock wave propagating away from the electrode toward the cell membrane. Utilizing previous data from cell membrane mechanical parameters, and nsEP generated shockwave parameters, an acoustic shock wave model based on the Helmholtz equation for sound pressure was developed and coupled to a cell membrane model with finite-element modeling in COMSOL. The acoustic structure interaction model was developed to illustrate the harmonic membrane displacements and stresses resulting from shockwave and membrane interaction based on Hooke's law. Poration is predicted by utilizing membrane mechanical breakdown parameters including cortical stress limits and hydrostatic pressure gradients.

  1. Nonlinear dynamics of shells conveying pulsatile flow with pulse-wave propagation. Theory and numerical results for a single harmonic pulsation

    Science.gov (United States)

    Tubaldi, Eleonora; Amabili, Marco; Païdoussis, Michael P.

    2017-05-01

    In deformable shells conveying pulsatile flow, oscillatory pressure changes cause local movements of the fluid and deformation of the shell wall, which propagate downstream in the form of a wave. In biomechanics, it is the propagation of the pulse that determines the pressure gradient during the flow at every location of the arterial tree. In this study, a woven Dacron aortic prosthesis is modelled as an orthotropic circular cylindrical shell described by means of the Novozhilov nonlinear shell theory. Flexible boundary conditions are considered to simulate connection with the remaining tissue. Nonlinear vibrations of the shell conveying pulsatile flow and subjected to pulsatile pressure are investigated taking into account the effects of the pulse-wave propagation. For the first time in literature, coupled fluid-structure Lagrange equations of motion for a non-material volume with wave propagation in case of pulsatile flow are developed. The fluid is modeled as a Newtonian inviscid pulsatile flow and it is formulated using a hybrid model based on the linear potential flow theory and considering the unsteady viscous effects obtained from the unsteady time-averaged Navier-Stokes equations. Contributions of pressure and velocity propagation are also considered in the pressure drop along the shell and in the pulsatile frictional traction on the internal wall in the axial direction. A numerical bifurcation analysis employs a refined reduced order model to investigate the dynamic behavior of a pressurized Dacron aortic graft conveying blood flow. A pulsatile time-dependent blood flow model is considered by applying the first harmonic of the physiological waveforms of velocity and pressure during the heart beating period. Geometrically nonlinear vibration response to pulsatile flow and transmural pulsatile pressure, considering the propagation of pressure and velocity changes inside the shell, is here presented via frequency-response curves, time histories, bifurcation

  2. 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).

  3. 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....

  4. Wave-function analysis of dynamic cancellation of ac Stark shifts in optical lattice clocks by use of pulsed Raman and electromagnetically-induced-transparency techniques

    International Nuclear Information System (INIS)

    Yoon, Tai Hyun

    2007-01-01

    We study analytically the dynamic cancellation of ac Stark shift in the recently proposed pulsed electromagnetically-induced-transparency (EIT-)Raman optical lattice clock based on the wave-function formalism. An explicit expression for the time evolution operator corresponding to the effective two-level interaction Hamiltonian has been obtained in order to explain the atomic phase shift cancellation due to the ac Stark shift induced by the time-separated laser pulses. We present how to determine an optimum value of the common detuning of the driving fields at which the atomic phase shift cancels completely with the parameters for the practical realization of the EIT-Raman optical lattice clock with alkaline-earth-metal atoms

  5. A novel device for measuring arterial stiffness using finger-toe pulse wave velocity: Validation study of the pOpmètre®.

    Science.gov (United States)

    Alivon, Maureen; Vo-Duc Phuong, Thao; Vignon, Virginie; Bozec, Erwan; Khettab, Hakim; Hanon, Olivier; Briet, Marie; Halimi, Jean-Michel; Hallab, Magid; Plichart, Matthieu; Mohammedi, Kamel; Marre, Michel; Boutouyrie, Pierre; Laurent, Stéphane

    2015-04-01

    The finger-toe pathway could be a good alternative for assessing arterial stiffness conveniently. To evaluate the accuracy of the pOpmètre®--a new device that measures finger-toe pulse wave velocity (ft-PWV). The pOpmètre has two photodiode sensors, positioned on the finger and the toe. Pulse waves are recorded continuously for 20 seconds, and the difference in pulse wave transit time between toe and finger (ft-TT) is calculated. The travelled distance is estimated using subject height. Study 1 compared ft-PWV with carotid-femoral PWV (cf-PWV) obtained by the reference method (SphygmoCor®) in 86 subjects (mean age 53±20 years), including 69 patients with various pathologies and 17 healthy normotensives. Study 2 compared changes in ft-PWV and cf-PWV during a cold pressor test in 10 healthy subjects. Study 3 assessed repeatability in 45 patients. ft-PWV correlated significantly with cf-PWV (R2=0.43; P<0.0001). A better correlation was found in terms of transit time (R2=0.61; P<0.0001). The discrepancy between transit times was related to age. The cold pressor test induced parallel changes in cf-PWV and ft-PWV, with increased aortic stiffness that was reversible during recovery. Intra-session repeatability was very good, with a coefficient of variation of 4.52%. The pOpmètre® allows measurement of arterial stiffness in routine clinical practice. The greatest advantages of ft-PWV are simplicity, rapidity, feasibility, acceptability by patients and correct agreement with the reference technique. Further studies are needed to adjust for bias and to validate the pOpmètre in larger populations. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  6. Influence of wave-front curvature on supercontinuum energy during filamentation of femtosecond laser pulses in water

    Science.gov (United States)

    Potemkin, F. V.; Mareev, E. I.; Smetanina, E. O.

    2018-03-01

    We demonstrate that using spatially divergent incident femtosecond 1240-nm laser pulses in water leads to an efficient supercontinuum generation in filaments. Optimal conditions were found when the focal plane is placed 100 -400 μ m before the water surface. Under sufficiently weak focusing conditions [numerical aperture (NA )laser pulses, the supercontinuum energy generated in divergent beams is higher than the supercontinuum energy generated in convergent beams. Analysis by means of the unidirectional pulse propagation equation shows a dramatic difference between filamentation scenarios of divergent and convergent beams, that explains corresponding features of the supercontinuum generation. Under strong focusing conditions (NA ⩾0.2 ) and high-energy laser pulses, the supercontinuum generation is suppressed for convergent beams in contrast to divergent beams that nevertheless are shown experimentally to allow supercontinuum generation. The presented technique of the supercontinuum generation in divergent beams in water is highly demanded in a development of femtosecond optical parametric amplifiers.

  7. Higgs Mode in the d -Wave Superconductor Bi2Sr2CaCu2O8 +x Driven by an Intense Terahertz Pulse

    Science.gov (United States)

    Katsumi, Kota; Tsuji, Naoto; Hamada, Yuki I.; Matsunaga, Ryusuke; Schneeloch, John; Zhong, Ruidan D.; Gu, Genda D.; Aoki, Hideo; Gallais, Yann; Shimano, Ryo

    2018-03-01

    We investigate the terahertz (THz)-pulse-driven nonlinear response in the d -wave cuprate superconductor Bi2Sr2CaCu2O8 +x (Bi2212) using a THz pump near-infrared probe scheme in the time domain. We observe an oscillatory behavior of the optical reflectivity that follows the THz electric field squared and is markedly enhanced below Tc . The corresponding third-order nonlinear effect exhibits both A1 g and B1 g symmetry components, which are decomposed from polarization-resolved measurements. A comparison with a BCS calculation of the nonlinear susceptibility indicates that the A1 g component is associated with the Higgs mode of the d -wave order parameter.

  8. CALCULATION-EXPERIMENTAL METHOD OF RESEARCH IN A METALLIC CONDUCTOR WITH THE PULSE CURRENT OF ELECTRONIC WAVEPACKAGES AND DE BROGLIE ELECTRONIC HALF-WAVES

    Directory of Open Access Journals (Sweden)

    M. I. Baranov

    2016-12-01

    Full Text Available Purpose. Development of calculation-experimental method for a discovery and study of electronic wavepackages (EWP and of de Broglie electronic half-waves in a metallic conductor with the pulse axial-flow current of high density. Methodology. Theoretical bases of the electrical engineering, bases of quantum physics, electrophysics bases of technique of high voltage and large pulsecurrents, and also bases of technique of measuring of permanent and variable electric value. Results. On the basis of generalization of results of research of features of the longitudinal wave periodic distributing of negatively charged transmitters of electric current of conductivity in the thin round continuous zincked steel wire offered and approved in the conditions of high-voltage laboratory method for a discovery and direct determination in him of geometrical parameters of «hot» and «cold» longitudinal areas quantized periodic longitudinal EWP and accordingly the mediated determination of values of the quantized lengths formative their de Broglie electronic half-waves. It is shown that results of close quantum mechanical calculations of EWP and quantized lengths λenz/2 of longitudinal de Broglie half-waves for the probed wire long l0 well comport with the results of the executed high temperature experiments on the powerful high-voltage generator of homopolar large pulse current of millisecond duration. Originality. First calculation-experimental a way the important for the theory of electricity fact of existence is set in a round metallic explorer with the impulsive axial-flow current of the quantized coherent de Broglie electronic half-waves, amplitudes of which at the quantum number of n=1,3,9 correspond the middles of «hot» longitudinal areas of EWP. Calculation quantum mechanical correlation of type of λenz/2=l0/n got experimental confirmation, in obedience to which on length of l0 conductor the integer of quantized electronic half-waves is always laid

  9. Relationships between lifestyle patterns and cardio-renal-metabolic parameters in patients with type 2 diabetes mellitus: A cross-sectional study.

    Science.gov (United States)

    Ogihara, Takeshi; Mita, Tomoya; Osonoi, Yusuke; Osonoi, Takeshi; Saito, Miyoko; Tamasawa, Atsuko; Nakayama, Shiho; Someya, Yuki; Ishida, Hidenori; Gosho, Masahiko; Kanazawa, Akio; Watada, Hirotaka

    2017-01-01

    While individuals tend to show accumulation of certain lifestyle patterns, the effect of such patterns in real daily life on cardio-renal-metabolic parameters remains largely unknown. This study aimed to assess clustering of lifestyle patterns and investigate the relationships between such patterns and cardio-renal-metabolic parameters. The study participants were 726 Japanese type 2 diabetes mellitus (T2DM) outpatients free of history of cardiovascular diseases. The relationship between lifestyle patterns and cardio-renal-metabolic parameters was investigated by linear and logistic regression analyses. Factor analysis identified three lifestyle patterns. Subjects characterized by evening type, poor sleep quality and depressive status (type 1 pattern) had high levels of HbA1c, alanine aminotransferase and albuminuria. Subjects characterized by high consumption of food, alcohol and cigarettes (type 2 pattern) had high levels of γ-glutamyl transpeptidase, triglycerides, HDL-cholesterol, blood pressure, and brachial-ankle pulse wave velocity. Subjects characterized by high physical activity (type 3 pattern) had low uric acid and mild elevation of alanine aminotransferase and aspartate aminotransferase. In multivariate regression analysis adjusted by age, gender and BMI, type 1 pattern was associated with higher HbA1c levels, systolic BP and brachial-ankle pulse wave velocity. Type 2 pattern was associated with higher HDL-cholesterol levels, triglycerides, aspartate aminotransferase, ɤ- glutamyl transpeptidase levels, and diastolic BP. The study identified three lifestyle patterns that were associated with distinct cardio-metabolic-renal parameters in T2DM patients. UMIN000010932.

  10. A Fast Multimodal Ectopic Beat Detection Method Applied for Blood Pressure Estimation Based on Pulse Wave Velocity Measurements in Wearable Sensors.

    Science.gov (United States)

    Pflugradt, Maik; Geissdoerfer, Kai; Goernig, Matthias; Orglmeister, Reinhold

    2017-01-14

    Automatic detection of ectopic beats has become a thoroughly researched topic, with literature providing manifold proposals typically incorporating morphological analysis of the electrocardiogram (ECG). Although being well understood, its utilization is often neglected, especially in practical monitoring situations like online evaluation of signals acquired in wearable sensors. Continuous blood pressure estimation based on pulse wave velocity considerations is a prominent example, which depends on careful fiducial point extraction and is therefore seriously affected during periods of increased occurring extrasystoles. In the scope of this work, a novel ectopic beat discriminator with low computational complexity has been developed, which takes advantage of multimodal features derived from ECG and pulse wave relating measurements, thereby providing additional information on the underlying cardiac activity. Moreover, the blood pressure estimations' vulnerability towards ectopic beats is closely examined on records drawn from the Physionet database as well as signals recorded in a small field study conducted in a geriatric facility for the elderly. It turns out that a reliable extrasystole identification is essential to unsupervised blood pressure estimation, having a significant impact on the overall accuracy. The proposed method further convinces by its applicability to battery driven hardware systems with limited processing power and is a favorable choice when access to multimodal signal features is given anyway.

  11. Proteome Analysis of Human Arterial Tissue Discloses Associations Between the Vascular Content of Small Leucine-Rich Repeat Proteoglycans and Pulse Wave Velocity

    DEFF Research Database (Denmark)

    Lyck Hansen, Maria; Beck, Hans Christian; Irmukhamedov, Akhmadjon

    2015-01-01

    OBJECTIVES: We hypothesized that arterial stiffness is associated with changes in the arterial protein profile, particularly of extracellular matrix components. We aimed at determining differentially expressed proteins by quantitative proteome analysis in arterial tissue from patients with differ......OBJECTIVES: We hypothesized that arterial stiffness is associated with changes in the arterial protein profile, particularly of extracellular matrix components. We aimed at determining differentially expressed proteins by quantitative proteome analysis in arterial tissue from patients...... with different degrees of arterial stiffness. APPROACH AND RESULTS: Arterial stiffness, assessed by carotid-femoral pulse wave velocity (PWV), central blood pressure and augmentation index by pulse wave analysis were measured the day before surgery in a group of patients undergoing coronary artery bypass...... grafting. Protein extracts of well-defined, homogenous, nonatherosclerotic individual samples of the left mammary artery from 10 of these patients with high PWV and 9 with low PWV were compared by quantitative proteome analysis, using tandem mass tag labeling and nano-liquid chromatography mass...

  12. Consequences of the magnetic field, sonic and radiofrequency waves and intense pulsed light on the labeling of blood constituents with technetium-99m

    International Nuclear Information System (INIS)

    Meyer, Patricia Froes; Costa, Iris do Ceu Clara; Brandao-Neto, Jose; Medeiros, Aldo da Cunha; Bonelli, Ludmila

    2007-01-01

    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 ( 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 99m Tc. Blood from Wistar rats was exposed to the cited sources. The labeling of Bl-Co with 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 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)

  13. 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)

  14. Improved Pulse Wave Velocity and Renal Function in Individualized Calcineurin Inhibitor Treatment by Immunomonitoring: The Randomized Controlled Calcineurin Inhibitor-Sparing Trial.

    Science.gov (United States)

    Sommerer, Claudia; Brocke, Janina; Bruckner, Thomas; Schaier, Matthias; Morath, Christian; Meuer, Stefan; Zeier, Martin; Giese, Thomas

    2018-03-01

    A new immune monitoring tool which assesses the expression of nuclear factor of activated T cells (NFAT)-regulated genes measures the functional effects of cyclosporine A. This is the first prospective randomized controlled study to compare standard pharmacokinetic monitoring by cyclosporine trough levels to NFAT-regulated gene expression (NFAT-RE). Expression of the NFAT-regulated genes was determined by qRT-PCR at cyclosporine trough and peak level. Cardiovascular risk was assessed by change of pulse wave velocity from baseline to month 6. Clinical follow-up was 12 months. In total, 55 stable kidney allograft recipients were enrolled. Mean baseline residual NFAT-RE was 13.1 ± 9.1%. Patients in the NFAT-RE group showed a significant decline in pulse wave velocity from baseline to month 6 versus the standard group (-1.7 ± 2.0 m/s vs 0.4 ± 1.4 m/s, P function was significantly better with NFAT-RE versus standard monitoring (Nankivell glomerular filtration rate: 68.5 ± 17.4 mL/min vs 57.2 ± 19.0 mL/min; P = 0.009). NFAT-RE as translational immune monitoring tool proved efficacious and safe in individualizing cyclosporine therapy, with the opportunity to reduce the cardiovascular risk and improve long-term renal allograft function.

  15. Long-term Saxagliptin Treatment Improves Endothelial Function but not Pulse Wave Velocity and Intima-Media Thickness in Type 2 Diabetic Patients.

    Science.gov (United States)

    Dell'Oro, Raffaella; Maloberti, Alessandro; Nicoli, Francesco; Villa, Paolo; Gamba, Pierluigi; Bombelli, Michele; Mancia, Giuseppe; Grassi, Guido

    2017-12-01

    Pharmacological inhibition of dipeptidyl-peptidase-4 may represent a promising therapeutic approach for glucose control and vascular protection. No information is available on the effects of saxagliptin (S) on aortic pulse wave velocity, carotid intima-media thickness and flow-mediated dilation (FMD, brachial artery) in diabetes. We investigated the long-term effects of S, as add-on therapy to metformin, on the above mentioned variables. In 16 patients with decompensated diabetes aortic pulse wave velocity, carotid intima-media thickness and FMD, office and 24-h ambulatory blood pressure, anthropometric, biochemical and metabolic parameters were measured at baseline and after 6 and 12 months of treatment. A group of 16 compensated diabetics served as controls. The two groups showed superimposable values of the different parameters, with the exception of glycated hemoglobin, blood glucose significantly (P function, related at least in part to the concomitant improvement in glucose metabolism. This may represent a first step in the chain of events leading to a reduction in the progression of the vascular atherogenic process.

  16. High-density optical data storage based on grey level recording in photobleaching polymers using two-photon excitation under ultrashort pulse and continuous wave illumination

    International Nuclear Information System (INIS)

    Ganic, D.; Day, D.; Gu, M.

    1999-01-01

    Full text: Two-photon excitation has been employed in three-dimensional optical data storage by many researchers in an attempt to increase the storage density of a given material. The probability of two-photon excitation is proportional to the squared intensity of the incident light; this effect produces excitation only within a small region of the focus spot. Another advantage of two-photon excitation is the use of infrared illumination, which results in the reduction of scattering and enables the recording of layers at a deep depth in a thick material. The storage density thus obtained using multi-layered bit optical recording can be as high as Tbit/cm 3 . To increase this storage density even further, grey level recording can be employed. This method utilises variable exposure times of a laser beam focused into a photobleaching sample. As a result, the bleached area possesses a certain pixel value which depends upon the exposure time; this can increase the storage density many times depending upon the number of grey levels used. Our experiment shows that it is possible to attain grey level recording using both ultrashort pulsed and continuous-wave illumination. Although continuous wave illumination requires an average power of approximately 2 orders of magnitude higher than that for ultrashort pulsed illumination, it is a preferred method of recording due to its relatively low system cost and compactness. Copyright (1999) Australian Optical Society

  17. 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.

  18. 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.

  19. Statistics of Acoustic Pulse Signals Through Nonlinear Internal Waves on the Continental Shelf of the Northeastern South China Sea

    National Research Council Canada - National Science Library

    Reeves, Justin M

    2008-01-01

    ...) was conducted from 13 - 15 April 2005 on the continental shelf in the northeast portion of the South China Sea to study the effects of nonlinear internal waves on the transmission of a 400-Hz signal...

  20. A sensitivity analysis of a personalized pulse wave propagation model for arteriovenous fistula surgery. Part A: Identification of most influential model parameters.

    Science.gov (United States)

    Huberts, W; de Jonge, C; van der Linden, W P M; Inda, M A; Tordoir, J H M; van de Vosse, F N; Bosboom, E M H

    2013-06-01

    Previously, a pulse wave propagation model was developed that has potential in supporting decision-making in arteriovenous fistula (AVF) surgery for hemodialysis. To adapt the wave propagation model to personalized conditions, patient-specific input parameters should be available. In clinics, the number of measurable input parameters is limited which results in sparse datasets. In addition, patient data are compromised with uncertainty. These uncertain and incomplete input datasets will result in model output uncertainties. By means of a sensitivity analysis the propagation of input uncertainties into output uncertainty can be studied which can give directions for input measurement improvement. In this study, a computational framework has been developed to perform such a sensitivity analysis with a variance-based method and Monte Carlo simulations. The framework was used to determine the influential parameters of our pulse wave propagation model applied to AVF surgery, with respect to parameter prioritization and parameter fixing. With this we were able to determine the model parameters that have the largest influence on the predicted mean brachial flow and systolic radial artery pressure after AVF surgery. Of all 73 parameters 51 could be fixed within their measurement uncertainty interval without significantly influencing the output, while 16 parameters importantly influence the output uncertainty. Measurement accuracy improvement should thus focus on these 16 influential parameters. The most rewarding are measurement improvements of the following parameters: the mean aortic flow, the aortic windkessel resistance, the parameters associated with the smallest arterial or venous diameters of the AVF in- and outflow tract and the radial artery windkessel compliance. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  1. 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.

  2. Usefulness of pulse-wave doppler tissue sampling and dobutamine stress echocardiography for identification of false positive inferior wall defects in SPECT

    International Nuclear Information System (INIS)

    Altinmakas, S.; Dagdeviren, B.; Turkmen, M.; Gursurer, M.; Say, B.; Tezel, T.; Ersek, B.

    2000-01-01

    False positive inferior wall perfusion defects restrict the accuracy of SPECT in diagnosis of coronary artery disease (CAD). Pulse-Wave Tissue Doppler (PWTD) has been recently proposed to assess regional wall motion velocities. The objectives of this study were to evaluate the presence of CAD by using PWTD during dobutamine stress echocardiography (DSE) in patients with an inferior perfusion defect detected by SPECT and compare PWTD parameters of normal cases with patients who had inferior perfusion defect and CAD. Sixty-five patients (mean age 58±8 years, 30 men) with a normal LV systolic function at rest according to echocardiographic evaluation with an inferior ischemia determined by SPECT and a control group (CG) of 34 normal cases (mean age 56±7 years, 16 men) were included in this study. All patients underwent a standard DSE (up to 40 μg/kg/min with additional atropine during sub-maximum heart rate responses). Pulse-wave Doppler tissue sampling of inferior wall was performed in the apical 2-chamber view at rest and stress. The coronary angiography was performed within 24 hours. The results were evaluated for the prediction of significant right coronary artery (RCA) and/or left circumflex coronary artery (CX) with narrowing (≥50% diameter stenosis, assessed by quantitative coronary angiography). It was observed that the peak stress mean E/A ratio was lower in patients with CAD when compared to patients without CAD (0.78±0.2 versus 1.29±0.11 p<0.0001). Also the peak stress E/A ratio of normal cases was significantly higher than patients who had CAD (1.19±0.3 versus 0.78±0.2 p<0.0001). When the cut off point for the E/A ratio was determined as 1, the sensitivity and specificity of dobutamine stress PWTD E/A were 89% and 86%, respectively. The peak stress E/A ratio was higher than 1 in all patients with a false positive perfusion defect. Systolic S velocity increase during DSE was significantly lower in patients with CAD (54%±17 versus 99%±24 p=0

  3. Rapid Synthesis of Gold Nano-Particles Using Pulse Waved Potential in a Non-Aqueous Electrolyte

    Directory of Open Access Journals (Sweden)

    Jang J.G.

    2017-06-01

    Full Text Available Rapid synthesis of gold nanoparticles (AuNPs by pulsed electrodeposition was investigated in the non-aqueous electrolyte, 1-ethyl-3-methyl-imidazoliumbis(trifluoro-methanesulfonylimide ([EMIM]TFSI with gold trichloride (AuCl3. To aid the dissolution of AuCl3, 1-ethyl-3-methyl-imidazolium chloride ([EMIM]Cl was used as a supporting electrolyte in [EMIM]TFSI. Cyclic voltammetry experiments revealed a cathodic reaction corresponding to the reduction of gold at −0.4 V vs. Pt-QRE. To confirm the electrodeposition process, potentiostatic electrodeposition of gold in the non-aqueous electrolyte was conducted at −0.4 V for 1 h at room temperature. To synthesize AuNPs, pulsed electrodeposition was conducted with controlled duty factor, pulse duration, and overpotential. The composition, particle-size distribution, and morphology of the AuNPs were confirmed by field-emission scanning electron microscopy (FE-SEM, energy-dispersive spectroscopy (EDS, and transmission electron microscopy (TEM. The electrodeposited AuNPs were uniformly distributed on the platinum electrode surface without any impurities arising from the non-aqueous electrolyte. The size distribution of AuNPs could be also controlled by the electrodeposition conditions.

  4. Simultaneously measured inter-arm and inter-leg systolic blood pressure differences and cardiovascular risk stratification: a systemic review and meta-analysis.

    Science.gov (United States)

    Singh, Sukhchain; Sethi, Ankur; Singh, Mukesh; Khosla, Kavia; Grewal, Navsheen; Khosla, Sandeep

    2015-08-01

    Association of inter-arm systolic blood pressure difference (IASBPD) with cardiovascular (CV) morbidity and mortality remains controversial. We aimed to thoroughly examine all available evidence on inter-limb blood pressure (BP) difference and its association with CV risk and outcomes. We searched PubMed, EMBASE, CINAHL, Cochrane library, and Ovid for studies reporting bilateral simultaneous BP measurements in arms or legs and risk of peripheral arterial disease (PAD), coronary artery disease, cerebrovascular disease, subclavian stenosis, or mortality. Random-effect meta-analysis was performed to compare effect estimates. Twenty-seven studies met inclusion criteria, but only 17 studies (18 cohorts) were suitable for analysis. IASBPD of 10 mmHg or more was associated with PAD (risk ratios, 2.22; 1.41-3.5; P = .0006; sensitivity 16.6%; 6.7-35.4; specificity 91.9%; 83.1-96.3; 8 cohorts; 4774 subjects), left ventricular mass index (standardized mean difference 0.21; 0.03-0.39; P = .02; 2 cohort; 1604 subjects), and brachial-ankle pulse wave velocity (PWV) (one cohort). Association of PAD remained significant at cutoff of 15 mmHg (risk ratios, 1.91; 1.28-2.84; P = .001; 5 cohorts; 1914 subjects). We could not find statistically significant direct association of coronary artery disease, cerebrovascular disease, CV, and all-cause mortality in subjects with IASBPD of 10 mmHg or more, 15 mmHg or more, and inter-leg systolic BP difference of 15 mmHg or more. Inter-leg BP difference of 15 mmHg or more was strong predictor of PAD (P = .0001) and brachial-ankle PWV (P = .0001). Two invasive studies showed association of IASBPD and subclavian stenosis (estimates could not be combined). In conclusion, inter-arm and leg BP differences are strong predictors of PAD. IASBPD may be associated with subclavian stenosis, high left ventricular mass effect, and higher brachial-ankle PWVs. Inter-leg BP difference may also be associated with high left ventricular mass effect and higher

  5. 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 two methods in a routine clinical setting. METHODS: For Study A, the displacements of 63 basal myocardial segments from 13 patients were examined with M-mode and compared with the velocity-time integral of PWTD and CTD velocities. For Study B, the basal lateral segments from 58 patients were examined...... with PWTD and CTD, and the peak myocardial velocities during systole (Sm), early diastole (Em), and late diastole (Am) were measured. RESULTS: Study A: CTD-based measurements of displacement were 12% lower than M-mode measurements (95% CI: -18%; -6%). PWTD velocity-time integrals measured at the outer edge...

  6. Reversed Cherenkov emission of terahertz waves from an ultrashort laser pulse in a sandwich structure with nonlinear core and left-handed cladding.

    Science.gov (United States)

    Bakunov, M I; Mikhaylovskiy, R V; Bodrov, S B; Luk'yanchuk, B S

    2010-01-18

    We propose a scheme for an experimental verification of the reversed Cherenkov effect in left-handed media. The scheme uses optical-to-terahertz conversion in a planar sandwichlike structure that consists of a nonlinear core cladded with a material that exhibits left-handedness at terahertz frequencies. The focused into a line femtosecond laser pulse propagates in the core and emits Cherenkov wedge of terahertz waves in the cladding. We developed a theory that describes terahertz generation in such a structure and calculated spatial distribution of the generated terahertz field, its energy spectrum, and optical-to-terahertz conversion efficiency. The proposed structure can be a useful tool for characterization of the electromagnetic properties of metamaterials in the terahertz frequency range.

  7. Frequency Characteristics of Surface Wave Generated by Single-Line Pulsed Laser Beam with Two Kinds of Spatial Energy Profile Models: Gaussian and Square-Like

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Ho Geon; Kim, Myung Hwan; Choi, Sung Ho; Kim, Chung Seok; Jhang, Kyung Young [Hanyang University, Seoul (Korea, Republic of)

    2012-08-15

    Using a single-line pulsed laser beam is well known as a useful noncontact method to generate a directional surface acoustic wave. In this method, different laser beam energy profiles produce different waveforms and frequency characteristics. In this paper, we considered two typical kinds of laser beam energy profiles, Gaussian and square-like, to find out a difference in the frequency characteristics. To achieve this, mathematical models were proposed first for Gaussian laser beam profile and square-like respectively, both of which depended on the laser beam width. To verify the theoretical models, experimental setups with a cylindrical lens and a line-slit mask were respectively designed to produce a line laser beam with Gaussian spatial energy profile and square-like. The frequency responses of the theoretical models showed good agreement with experimental results in terms of the existence of harmonic frequency components and the shift of the first peak frequencies to low.

  8. Factors associated with high brachial–ankle pulse wave velocity in non-hypertensive and appropriately treated hypertensive patients with atherosclerotic risk factors

    Directory of Open Access Journals (Sweden)

    Ato D

    2017-10-01

    Full Text Available Dai Ato,1 Toshitami Sawayama2 1Gakujutsu Shien (Academic Support Co., Ltd. Tokyo, 2Sawayama Clinic, Okayama, Japan Abstract: While pulse wave velocity (PWV correlates with blood pressure (BP, its extent differs between patients, and some cases of high PWV in normotensives are present. Moreover, PWV frequently remains high in hypertensive patients despite adequate BP control. The factors associated with such phenomena are yet to be elucidated. Here, we investigated the factors associated with brachial–ankle PWV (baPWV in 107 patients whose systolic BP was under 140 mmHg at their latest baPWV measurement. There were 64 controlled hypertensives and 43 normotensives. Multivariate regression analysis identified age, hypertension, body mass index (BMI, systolic BP, and heart rate (HR as independent factors for baPWV. Next, we divided the subjects into groups according to their age (in 5-year increments and calculated the mean and standard deviation (SD of the baPWV for each group. For each age group, we defined patients with a baPWV above the mean + SD baPWV for the group as the high-baPWV cohort. Multivariate logistic regression analysis revealed that BMI, hypertension, and smoking were independent determinants of a high-baPWV subject. This represents the first study to report the existence of the hypertensive state itself as one of the independent predictors of high baPWV in normotensive and well-treated hypertensive patients. This finding implies that the hypertensive state itself possibly worsens arterial stiffness independently from aging in spite of adequate BP maintenance. To prevent the early progression of arterial stiffness, the application of an appropriate intervention during the early stages of hypertension is important and the continuation of an appropriate BP treatment is suggested. Keywords: arterial stiffness, brachial–ankle pulse wave velocity, heart failure, hypertension, peripheral arterial disease

  9. [Experimental study of brain lesions after combined coaxial exposure to high-peaked pulse wave form CO2 and Nd: YAG lasers on the brain].

    Science.gov (United States)

    Tsuyumu, M; Verasques, G; Yamazaki, S; Kuroiwa, T; Suzuki, R; Takei, H; Suzuki, K; Inaba, Y

    1985-04-01

    The CO2 laser is useful for cutting and vaporization but not for coagulation and hemostasis. On the contrary, YAG laser is effective for coagulation and hemostasis but not for cutting. The purpose of this study is to examine the effect of the exposure of combined, coaxial CO2 and YAG laser on the animal brain to supplement the advantages and draw-backs of each other. To compare these results, each of non-combined pulse wave form CO2 and YAG lasers was employed separately. The lasers in this study were pulse wave form CO2 and YAG lasers, employed separately or simultaneously using 130 YZ of Nihon Infrared Industries Company. Japanese white rabbits were anesthetized with pentobarbital. Fronto-parietal burr holes were made, the dura was removed and then Evans blue solution was injected intravenously. The lasers were employed to the cerebral cortex without great vessels using a micromanipulator attached to the operative microscope with a distance of 30 cm. The spot size was 700 mu for CO2 laser and 1200 mu for YAG laser. The first experiment was to see the effect of nine combinations of simultaneous coaxial CO2 of 2, 4 and 8 watts and YAG lasers of 10, 20 and 40 watts, 1 sec on the brain. In the second experiment, also combining two lasers, the exposure time of YAG laser was elongated from 1 or 2 seconds into 2 or 4 seconds and the arrangement of powers was the same as that of the first experiment. The lesions were thus made in 18 different conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Echocardiographic Assessment of Left Ventricular Function in Healthy Horses and in Horses with Heart Disease Using Pulsed-Wave Tissue Doppler Imaging.

    Science.gov (United States)

    Koenig, T R; Mitchell, K J; Schwarzwald, C C

    2017-03-01

    Assessment of left ventricular (LV) function by tissue Doppler imaging (TDI) is not well established in horses with heart disease. To describe the use of pulsed-wave (PW) TDI for the assessment of LV function, establish reference intervals, investigate effects of mitral regurgitation (MR), aortic regurgitation (AR), and primary myocardial disease (MD), and provide proof of concept for the use of PW TDI in Warmblood horses with heart disease. Thirty healthy horses, 38 horses with MR, 25 with AR, 8 with MD. Echocardiograms were retrospectively analyzed. Reference intervals were calculated. PW TDI indices of healthy horses and horses with MR, AR, and MD were compared by one-way ANOVA and Dunnett's test. A complete set of PW TDI variables could be obtained in 94 of 101 horses. Variables corresponding to isovolumic intervals were most difficult to measure. Valvular regurgitation influenced variables describing isovolumic contraction and ejection. Horses with MD had significantly shortened ET m (-118.5 [-154.1 to -82.9] ms; mean difference [95% CI of difference of means]), increased PEP m /ET m (0.11 [0.05 to 0.17]), prolonged IMP m (0.28 [0.18 to 0.37]), increased S 1 (8.9 [5.2 to 12.6] cm/s), and decreased E 1 (-2.6 [-4.7 to -0.5] cm/s), E m (-14.2 [-19.9 to -8.5] cm/s), and E m /A m ratio (-1.6 [-2.6 to -0.6]). Pulsed-wave TDI might be useful for detection of LV dysfunction in horses with primary MD. The clinical value of TDI in horses with MR and AR remains uncertain. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  11. 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 .

  12. Retrospective Study on Laser Treatment of Oral Vascular Lesions Using the "Leopard Technique": The Multiple Spot Irradiation Technique with a Single-Pulsed Wave.

    Science.gov (United States)

    Miyazaki, Hidetaka; Ohshiro, Takafumi; Romeo, Umberto; Noguchi, Tadahide; Maruoka, Yutaka; Gaimari, Gianfranco; Tomov, Georgi; Wada, Yoshitaka; Tanaka, Kae; Ohshiro, Toshio; Asamura, Shinichi

    2018-06-01

    This study aimed to retrospectively evaluate the efficacy and safety of laser treatment of oral vascular lesions using the multiple spot irradiation technique with a single-pulsed wave. In laser therapy for vascular lesions, heat accumulation induced by excessive irradiation can cause adverse events postoperatively, including ulcer formation, resultant scarring, and severe pain. To prevent heat accumulation and side effects, we have applied a multiple pulsed spot irradiation technique, the so-called "leopard technique" (LT) to oral vascular lesions. This approach was originally proposed for laser treatment of nevi. It can avoid thermal concentration at the same spot and spare the epithelium, which promotes smooth healing. The goal of the study was to evaluate this procedure and treatment outcomes. The subjects were 46 patients with 47 oral vascular lesions treated with the LT using a Nd:YAG laser (1064 nm), including 24 thick lesions treated using a combination of the LT and intralesional photocoagulation. All treatment outcomes were satisfactory without serious complications such as deep ulcer formation, scarring, bleeding, or severe swelling. Laser therapy with the LT is a promising less-invasive treatment for oral vascular lesions.

  13. Continuous micro-feeding of fine cohesive powders actuated by pulse inertia force and acoustic radiation force in ultrasonic standing wave field.

    Science.gov (United States)

    Wang, Hongcheng; Wu, Liqun; Zhang, Ting; Chen, Rangrang; Zhang, Linan

    2018-07-10

    Stable continuous micro-feeding of fine cohesive powders has recently gained importance in many fields. However, it remains a great challenge in practice because of the powder aggregate caused by interparticle cohesive forces in small capillaries. This paper describes a novel method of feeding fine cohesive powder actuated by a pulse inertia force and acoustic radiation force simultaneously in an ultrasonic standing wave field using a tapered glass nozzle. Nozzles with different outlet diameters are fabricated using glass via a heating process. A pulse inertia force is excited to drive powder movement to the outlet section of the nozzle in a consolidated columnar rod mode. An acoustic radiation force is generated to suspend the particles and make the rod break into large quantities of small agglomerates which impact each other randomly. So the aggregation phenomenon in the fluidization of cohesive powders can be eliminated. The suspended powder is discharged continuously from the nozzle orifice owing to the self-gravities and collisions between the inner particles. The micro-feeding rates can be controlled accurately and the minimum values for RespitoseSV003 and Granulac230 are 0.4 mg/s and 0.5 mg/s respectively. The relative standard deviations of all data points are below 0.12, which is considerably smaller than those of existing vibration feeders with small capillaries. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Wave-packet dynamics in alkaline dimers. Investigation and control through coherent excitation with fs-pulses

    International Nuclear Information System (INIS)

    Sauer, F.N.B.

    2007-01-01

    During my PhD thesis I investigated alkaline dimers with coherent control in a molecular beam as well as with pump-probe spectroscopy in a magneto-optical trap (MOT). The aim of the coherent control experiments were the isotope selective ionization with phase- and amplitude-shaped fs-pulses. Chapter 4 described the gained results of isotope selective ionization of NaK and KRb in a molecular beam by using different pulse formers. For the NaK dimer was the reached optimization factor R Ph and Ampl 770 =R max /R min =25 between maximization and minimization of the isotopomer ratio ( 23 Na 39 K) + /( 23 Na 41 K) + with phase and amplitude modulation of the fs-pulse with a central wavelength of λ=770 nm. From the electronic ground-state X(1) 1 Σ + ;ν''=0 transfers a one-photon-excitation population in the first excited A(2) 1 Σ + state. The coherent control experiment on KRb was used to maximize and minimize the isotopomer ratio ( 124 KRb) + /( 126 KRb) + . It was the first coherent control experiment with a spectral resolution of 1.84 cm -1 /Pixel. For the phase and amplitude optimization was the received optimization factor between minimization and maximization of the isotopomer ratio R Ph and Ampl =R max /R min =7 at a central wavelength of 840 nm. The results showed a stepwise excitation process from the electronic ground-state in the first excited (2) 1 Σ + state with a further excitation, that is possible over three resonant energy potential curves into the ionic ground-state. In the second part of my thesis I realized pump-probe spectroscopy of Rb 2 dimers in a dark SPOT. (orig.)

  15. Energy of a shock wave generated in different metals under irradiation by a high-power laser pulse

    Czech Academy of Sciences Publication Activity Database

    Gus'kov, S. Yu.; Kasperczuk, A.; Pisarczyk, T.; Borodziuk, S.; Ullschmied, Jiří; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Skála, Jiří; Pisarczyk, P.

    2007-01-01

    Roč. 105, č. 4 (2007), s. 793-802 ISSN 1063-7761 R&D Projects: GA MŠk(CZ) LC528 Grant - others:HPC Europa(XE) RII3-CT-2003-506350 Program:FP6 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z10100523 Source of funding: R - rámcový projekt EK Keywords : shock waves * laser radiation * laser plasma * inertial confinement * PALS laser Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.075, year: 2007

  16. Ultra-long pulse operation using lower hybrid waves on the superconducting high field tokamak TRIAM-1M

    International Nuclear Information System (INIS)

    Moriyama, S.; Nakamura, Y.; Nagao, A.; Jotaki, E.; Nakamura, K.; Hiraki, N.; Itoh, S.

    1990-01-01

    Ultra-long pulse operation (>3 min) was achieved on the superconducting high field tokamak TRIAM-1M. In this operation, the plasma current was maintained with a relatively peaked current distribution by the 2.45 GHz radiofrequency power (P RF ≤ 35 kW) alone. A stationary plasma with a driven current of up to 35 kA and a line averaged electron density of up to 3x10 12 cm -3 was produced by precise plasma position and gas feed control. The extremely long discharge showed the interesting characteristics that the high temperatures of about 1 keV for the electrons and about 0.5 keV for the ions were kept almost constant during steady state current drive and that there was no impurity accumulation which could have a fatally adverse effect on steady state tokamak operation. (author). 16 refs, 17 figs

  17. 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

    1999-06-01

    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

  18. 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.

    Science.gov (United States)

    Ragab, Seham M; Fathy, Waleed M; El-Aziz, Walaa FAbd; Helal, Rasha T

    2015-01-01

    Cardiac iron toxicity is the leading cause of death among β-halassaemia major (TM) patients. Once heart failure becomes overt, it is difficult to reverse. To investigate non-overt cardiac dysfunctions in TM patients using pulsed wave Tissue Doppler Imaging (TD I) and its relation to iron overload and brain natriuretic peptide (BNP). Thorough clinical, conventional echo and pulsed wave TDI parameters were compared between asymptomatic 25 β-TM patients and 20 age and gender matched individuals. Serum ferritin and plasma BNP levels were assayed by ELISA. TM patients had significant higher mitral inflow early diastolic (E) wave and non significant other conventional echo parameters. In the patient group, pulsed wave TDI revealed systolic dysfunctions, in the form of significant higher isovolumetric contraction time (ICT), and lower ejection time (E T), with diastolic dysfunction in the form of higher isovolumetric relaxation time (IRT), and lower mitral annulus early diastolic velocity E' (12.07 ±2.06 vs 15.04±2.65, P= 0.003) compared to the controls. Plasma BNP was higher in patients compared to the controls. Plasma BNP and serum ferritin had a 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 ratio wave TDI is an important diagnostic tool for latent cardiac dysfunction in iron-loaded TM patients and is related to iron overload and BNP.

  19. Influence of the trigger technique on ventricular function measurements using 3-Tesla magnetic resonance imaging: comparison of ECG versus pulse wave triggering

    International Nuclear Information System (INIS)

    Sievers, Burkhard; Wiesner, Marco; Kiria, Nino; Speiser, Uwe; Schoen, Steffen; Strasser, Ruth H.

    2011-01-01

    Background Three Tesla cardiovascular magnetic resonance imaging (3T-CMR) is increasingly used in clinical practice. Despite many advantages one drawback is that ECG signal disturbances and artifacts increase with higher magnetic field strength resulting in trigger problems and false gating. This particularly affects cardiac imaging because most pulse sequences require ECG triggering. Pulse wave (PW) triggering is robust and might have advantages over ECG triggering. Purpose To evaluate differences in left ventricular (LV) function as an integral part of most CMR studies between ECG- and PW-triggered short-axis imaging using 3T-CMR. Material and Methods Forty-three patients underwent multiple short-axis cine imaging for LV-function assessment with ECG and PW triggering using standard multi breath hold steady-state free precession. LV-volumes (EDV, ESV), ejection fraction (EF), and mass were determined by slice summation. LV-wall motion was assessed by using a 4-point scoring scale. Bland Altman statistics for inter-observer variability were performed. Results ECG triggering failed in 15 patients (34.8%). Thus, analysis was performed in 28 patients (13 with impaired LV function). Difference in volumes (EDV 0.13 ± 1.8 mL, ESV 0.59 ± 1.1 mL), EF (-0.32 ± 0.6%) and mass (0.01 ± 1.1 g) between ECG and PW triggering were very small and significant only for ESV and EF (p 0.011). In patients with impaired LV function (n = 19) differences were not significant (p = 0.128). Wall motion scores did not differ between ECG and PW triggering (p = 0.295). Inter-observer variability for function measurements was low. Conclusion Short-axis cine imaging for LV-function assessment can accurately be performed using PW triggering on 3T magnets, and may be used in clinical practice when ECG triggering is disturbed

  20. 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.

  1. Photobiomodulation with Pulsed and Continuous Wave Near-Infrared Laser (810 nm, Al-Ga-As Augments Dermal Wound Healing in Immunosuppressed Rats.

    Directory of Open Access Journals (Sweden)

    Gaurav K Keshri

    Full Text Available Chronic non-healing cutaneous wounds are often vulnerable in one or more repair phases that prevent normal healing and pose challenges to the use of conventional wound care modalities. In immunosuppressed subject, the sequential stages of healing get hampered, which may be the consequences of dysregulated or stagnant wound inflammation. Photobiomodulation (PBM or low-level laser (light therapy (LLLT emerges as a promising drug-free, non-invasive biophysical approach for promoting wound healing, reduction of inflammation, pain and restoration of functions. The present study was therefore undertaken to evaluate the photobiomodulatory effects of 810 nm diode laser (40 mW/cm2; 22.6 J/cm2 with pulsed (10 and 100 Hz, 50% duty cycle and continuous wave on full-thickness excision-type dermal wound healing in hydrocortisone-induced immunosuppressed rats. Results clearly delineated that 810 nm PBM at 10 Hz was more effective over continuous and 100 Hz frequency in accelerating wound healing by attenuating the pro-inflammatory markers (NF-kB, TNF-α, augmenting wound contraction (α-SM actin, enhancing cellular proliferation, ECM deposition, neovascularization (HIF-1α, VEGF, re-epithelialization along with up-regulated protein expression of FGFR-1, Fibronectin, HSP-90 and TGF-β2 as compared to the non-irradiated controls. Additionally, 810 nm laser irradiation significantly increased CCO activity and cellular ATP contents. Overall, the findings from this study might broaden the current biological mechanism that could be responsible for photobiomodulatory effect mediated through pulsed NIR 810 nm laser (10 Hz for promoting dermal wound healing in immunosuppressed subjects.

  2. Photoelectrocatalytic decomposition of ethylene using TiO2/activated carbon fiber electrode with applied pulsed direct current square-wave potential

    International Nuclear Information System (INIS)

    Ye, Sheng-ying; Zheng, Sen-hong; Song, Xian-liang; Luo, Shu-can

    2015-01-01

    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 2 or modified TiO 2 and activated carbon fiber (ACF) was used. • TiO 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 2 H 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 2 ) photocatalyst or γ-irradiated TiO 2 (TiO 2 * ) 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 2 /ACF cell or TiO 2 * /ACF cell enhanced the efficiency of photocatalytic degradation and PEC degradation. Gamma irradiation of TiO 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 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 follows: 358.36 Hz frequency, 55.79% duty cycle, and 64.65 V

  3. Pulse wave propagation in a model human arterial network: Assessment of 1-D visco-elastic simulations against in vitro measurements.

    Science.gov (United States)

    Alastruey, Jordi; Khir, Ashraf W; Matthys, Koen S; Segers, Patrick; Sherwin, Spencer J; Verdonck, Pascal R; Parker, Kim H; Peiró, Joaquim

    2011-08-11

    The accuracy of the nonlinear one-dimensional (1-D) equations of pressure and flow wave propagation in Voigt-type visco-elastic arteries was tested against measurements in a well-defined experimental 1:1 replica of the 37 largest conduit arteries in the human systemic circulation. The parameters required by the numerical algorithm were directly measured in the in vitro setup and no data fitting was involved. The inclusion of wall visco-elasticity in the numerical model reduced the underdamped high-frequency oscillations obtained using a purely elastic tube law, especially in peripheral vessels, which was previously reported in this paper [Matthys et al., 2007. Pulse wave propagation in a model human arterial network: Assessment of 1-D numerical simulations against in vitro measurements. J. Biomech. 40, 3476-3486]. In comparison to the purely elastic model, visco-elasticity significantly reduced the average relative root-mean-square errors between numerical and experimental waveforms over the 70 locations measured in the in vitro model: from 3.0% to 2.5% (p<0.012) for pressure and from 15.7% to 10.8% (p<0.002) for the flow rate. In the frequency domain, average relative errors between numerical and experimental amplitudes from the 5th to the 20th harmonic decreased from 0.7% to 0.5% (p<0.107) for pressure and from 7.0% to 3.3% (p<10(-6)) for the flow rate. These results provide additional support for the use of 1-D reduced modelling to accurately simulate clinically relevant problems at a reasonable computational cost. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Four-wave-mixing and nonlinear cavity dumping of 280 picosecond 2nd Stokes pulse at 1.3 μm from Nd:SrMoO4 self-Raman laser

    International Nuclear Information System (INIS)

    Smetanin, S N; Ivleva, L I; Jelínek, M Jr; Kubeček, V; Jelínková, H; Shurygin, A S

    2016-01-01

    The 280 picosecond 2nd Stokes Raman pulses at 1.3 μm were generated directly from the miniature diode-pumped Nd:SrMoO 4 self-Raman laser. Using the 90° phase matching insensitive to the angular mismatch, the self-Raman laser allowed for the achievement of the four-wave-mixing generation of the 2nd Stokes Raman pulse directly in the active Nd:SrMoO 4 crystal at stimulated Raman scattering (SRS) self-conversion of the laser radiation. The passive Cr:YAG Q-switching and nonlinear cavity dumping was used without any phase locking device. (letter)

  5. Combination of Echocardiography and Pulse Wave Velocity Provides Clues for the Differentiation between White Coat Hypertension and Hypertension in Postmenopausal Women.

    Science.gov (United States)

    Suzuki, Hiromichi; Kobayashi, Kazuhiro; Okada, Hirokazu

    2014-05-01

    To determine whether or not noninvasive assessment of the cardiovascular system can discriminate white coat hypertension and hypertension in postmenopausal women. The major reason is the high prevalence of white coat hypertension in these subjects and the uncertain associations of white coat hypertension with cardiovascular risk. Selected women were required to be naturally or surgically menopausal for at least 1 year but not more than 5 years past their menstrual period. White coat hypertension patients were defined as subjects who had office blood pressures >150/90 mm Hg but who had both systolic and diastolic ambulatory pressures coat hypertension based on the criteria in the trial. Pulse wave patterns were different between subjects with white coat hypertension and those with hypertension. PWV of subjects with white coat hypertension was 1.32 ± 0.33 m/s and that of patients with hypertension was 1.46 ± 0.37 m/s (p coat hypertension could be easily differentiated from hypertension. The combination of blood pressure self-monitoring, echocardiographic data, and PWV can be a powerful indicator for the treatment of hypertension in postmenopausal women.

  6. 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.

  7. 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.

  8. Kinetics of the Thermal Decomposition of Tetramethylsilane behind the Reflected Shock Waves in a Single Pulse Shock Tube (SPST) and Modeling Study

    Science.gov (United States)

    Parandaman, A.; Sudhakar, G.; Rajakumar, B.

    Thermal reactions of Tetramethylsilane (TMS) diluted in argon were studied behind the reflected shock waves in a single-pulse shock tube (SPST) over the temperature range of 1085-1221 K and pressures varied between 10.6 and 22.8 atm. The stable products resulting from the decomposition of TMS were identified and quantified using gas chromatography and also verified with Fourier Transform Infrared (FTIR) spectrometer. The major reaction products are methane (CH4) and ethylene (C2H4). The minor reaction products are ethane (C2H6) and propylene (C3H6). The initiation of mechanism in the decomposition of TMS takes plays via the Si-C bond scission by ejecting the methyl radicals (CH3) and trimethylsilyl radicals ((CH3)3Si). The measured temperature dependent rate coefficient for the total decomposition of TMS was to be ktotal = 1.66 ×1015 exp (-64.46/RT) s-1 and for the formation of CH4 reaction channel was to be k = 2.20 × 1014 exp (-60.15/RT) s-1, where the activation energies are given in kcal mol-1. A kinetic scheme containing 17 species and 28 elementary reactions was used for the simulation using chemical kinetic simulator over the temperature range of 1085-1221 K. The agreement between the experimental and simulated results was satisfactory.

  9. A Visible and Passive Millimeter Wave Image Fusion Algorithm Based on Pulse-Coupled Neural Network in Tetrolet Domain for Early Risk Warning

    Directory of Open Access Journals (Sweden)

    Yuanjiang Li

    2018-01-01

    Full Text Available An algorithm based on pulse-coupled neural network (PCNN constructed in the Tetrolet transform domain is proposed for the fusion of the visible and passive millimeter wave images in order to effectively identify concealed targets. The Tetrolet transform is applied to build the framework of the multiscale decomposition due to its high sparse degree. Meanwhile, a Laplacian pyramid is used to decompose the low-pass band of the Tetrolet transform for improving the approximation performance. In addition, the maximum criterion based on regional average gradient is applied to fuse the top layers along with selecting the maximum absolute values of the other layers. Furthermore, an improved PCNN model is employed to enhance the contour feature of the hidden targets and obtain the fusion results of the high-pass band based on the firing time. Finally, the inverse transform of Tetrolet is exploited to obtain the fused results. Some objective evaluation indexes, such as information entropy, mutual information, and QAB/F, are adopted for evaluating the quality of the fused images. The experimental results show that the proposed algorithm is superior to other image fusion algorithms.

  10. Comparison by magnetic resonance phase contrast imaging of pulse-wave velocity in patients with single ventricle who have reconstructed aortas versus those without.

    Science.gov (United States)

    Fogel, Mark A; Li, Christine; Nicolson, Susan C; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Keller, Marc S; Harris, Matthew A; Yoganathan, Ajit P; Whitehead, Kevin K

    2014-12-15

    Pulse-wave velocity (PWV), a measure of arterial stiffness, is a known independent risk factor for cardiovascular events. Patients with single ventricle who undergo aortic to pulmonary anastomosis (recon) have noncompliant patch material inserted into the neoaorta, possibly increasing vessel stiffness and afterload. The purpose of this study is to determine if PWV in patients with single ventricle differed between those who did and those who did not undergo aortic reconstruction (nonrecon). We retrospectively reviewed cardiac magnetic resonance anatomic, cine, and phase contrast evaluations in the ascending aorta and descending aorta (DAo) at the level of the diaphragm data from 126 patients with single ventricle (8.6 ± 8.0 years) from January 2012 to May 2013. Significance = p 13 years old had a higher PWV than those 13 years old, PWV of those with recon was higher than nonrecon DAo distensibility was similar between both groups. There was no difference in age, body surface area, or cardiac index between recon and nonrecon. No correlations between various hemodynamic and ventricular function parameters with PWV were noted. In conclusion, PWV in recon is higher than in nonrecon with similar DAo distensibility implicating the aortic reconstruction as a possible cause of increased afterload; older recon patients have stiffer aortas than younger ones, possibly imposing an additional cardiovascular risk in the future. Other biomaterials may potentially moderate PWV if clinical outcome is adversely affected. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Comparison by Magnetic Resonance Phase Contrast of Pulse Wave Velocity in Patients with Single Ventricle and Reconstructed Aortas versus Those Without

    Science.gov (United States)

    Fogel, Mark A.; Li, Christine; Nicolson, Susan C; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Keller, Marc S.; Harris, Matthew A.; Yoganathan, Ajit P; Whitehead, Kevin K.

    2015-01-01

    Pulse wave velocity (PWV), a measure of arterial stiffness, is a known independent risk factor for cardiovascular events. Single ventricle patients who undergo aortic to pulmonary anastomosis (recon) have non-compliant patch material inserted into the neo-aorta, possibly increasing vessel stiffness and afterload. The purpose of this study is to determine if PWV differed in single ventricle patients who did and did not undergo aortic reconstruction (no-recon). We retrospectively reviewed cardiac magnetic resonance anatomic, cine and phase contrast evaluations in the ascending (AAo) and descending aorta (DAo) at the level of the diaphragm data from 126 single ventricle patients (8.6±8.0 years) from January 2012 to May, 2013. Significance = P 13 years had a higher PWV than those < 7 years (4.5±0.6 vs 3.5±0.7 m/s, P=0.004). DAo distensibility was similar between both groups. There was no difference in age, body surface area or cardiac index between recon and no-recon. No correlations between various hemodynamic and ventricular function parameters with PWV were noted. In conclusion, PWV in recon is higher than in no-recon with similar DAo distensibility implicating the aortic reconstruction as a possible cause of increased afterload; older recon have stiffer aortas than younger ones possibly imposing an additional cardiovascular risk in the future. Other biomaterials may potentially moderate PWV if clinical outcome is adversely affected. PMID:25432153

  12. Effects of Short-Term Exenatide Treatment on Regional Fat Distribution, Glycated Hemoglobin Levels, and Aortic Pulse Wave Velocity of Obese Type 2 Diabetes Mellitus Patients

    Directory of Open Access Journals (Sweden)

    Ju-Young Hong

    2016-03-01

    Full Text Available BackgroundMost type 2 diabetes mellitus patients are obese and have obesity related vascular complications. Exenatide treatment is well known for both decreasing glycated hemoglobin levels and reduction in body weight. So, this study aimed to determine the effects of exenatide on body composition, glycated hemoglobin levels, and vascular stiffness in obese type 2 diabetes mellitus patients.MethodsFor 1 month, 32 obese type 2 diabetes mellitus patients were administered 5 µg of exenatide twice daily. The dosage was then increased to 10 µg. Patients' height, body weight, glycated hemoglobin levels, lipid profile, pulse wave velocity (PWV, body mass index, fat mass, and muscle mass were measured by using Inbody at baseline and after 3 months of treatment.ResultsAfter 3 months of treatment, glycated hemoglobin levels decreased significantly (P=0.007. Triglyceride, total cholesterol, and low density lipoprotein levels decreased, while aspartate aminotransferase and alanine aminotransferase levels were no change. Body weight, and fat mass decreased significantly (P=0.002 and P=0.001, respectively, while interestingly, muscle mass did not decrease (P=0.289. In addition to, Waist-to-hip ratio and aortic PWV decreased significantly (P=0.006 and P=0.001, respectively.ConclusionEffects of short term exenatide use in obese type 2 diabetes mellitus with cardiometabolic high risk patients not only reduced body weight without muscle mass loss, body fat mass, and glycated hemoglobin levels but also improved aortic PWV in accordance with waist to hip ratio.

  13. 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.

  14. Age and gender differences in the influences of eNOS T-786C polymorphism on arteriosclerotic parameters in general population in Japan.

    Science.gov (United States)

    Hashimoto, Marowa; Miyai, Nobuyuki; Hattori, Sonomi; Iwahara, Akihiko; Utsumi, Miyoko; Arita, Mikio; Takeshita, Tatsuya

    2016-07-01

    The influence of T-786C polymorphism in the promoter region of endothelial nitric oxide synthase (eNOS) on arteriosclerotic parameters by age and gender were examined. Brachial-ankle pulse wave velocity (baPWV), heart-rate adjusted augmentation index (AIx@75), pulse pressure (PP) and albumin-creatinine ratio (ACR) were assessed as arteriosclerotic parameters in addition to non-high-density lipoprotein cholesterol (non-HDL-C) to HDL-C (non-HDL-C/HDL-C) ratio in 1499 participants. T-786C polymorphism (rs2070744) was screened using a TaqMan allelic discrimination assay. Analyses of covariance were carried. Women with the non-C allele showed significantly lower AIx@75 in participants aged gender differences, possibly involving antioxidative and/or endothelial signaling other than inflammatory signaling.

  15. 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.

  16. Electromagnetic pulses, localized and causal

    Science.gov (United States)

    Lekner, John

    2018-01-01

    We show that pulse solutions of the wave equation can be expressed as time Fourier superpositions of scalar monochromatic beam wave functions (solutions of the Helmholtz equation). This formulation is shown to be equivalent to Bateman's integral expression for solutions of the wave equation, for axially symmetric solutions. A closed-form one-parameter solution of the wave equation, containing no backward-propagating parts, is constructed from a beam which is the tight-focus limit of two families of beams. Application is made to transverse electric and transverse magnetic pulses, with evaluation of the energy, momentum and angular momentum for a pulse based on the general localized and causal form. Such pulses can be represented as superpositions of photons. Explicit total energy and total momentum values are given for the one-parameter closed-form pulse.

  17. Validation of a Piezoelectric Sensor Array-Based Device for Measurement of Carotid-Femoral Pulse Wave Velocity: The Philips Prototype.

    Science.gov (United States)

    Xu, Shao-Kun; Hong, Xiang-Fei; Cheng, Yi-Bang; Liu, Chang-Yuan; Li, Yan; Yin, Bin; Wang, Ji-Guang

    2018-03-01

    Multiple piezoelectric pressure mechanotransducers topologized into an array might improve efficiency and accuracy in collecting arterial pressure waveforms for measurement of pulse wave velocity (PWV). In the present study, we validated a piezoelectric sensor array-based prototype (Philips) against the validated and clinically widely used Complior device (Alam Medical). We recruited 33 subjects with a wide distribution of PWV. For the validation, PWV was measured sequentially with the Complior device (four times) and the Philips prototype (three times). With the 99 paired PWV values, we investigated the agreement between the Philips prototype and the Complior device using Pearson correlation analysis and Bland-Altman plot. We also performed analysis on the determinants and reproducibility of PWV measured with both devices. The correlation coefficient for PWV measured with the two devices was 0.92 ( p prototype slightly overestimated PWV by 0.24 (± 2 standard deviations, ± 1.91) m/s, especially when PWV was high. The correlation coefficient between the difference and the average of the Philips and Complior measurements was 0.21 ( p = 0.035). Nonetheless, they had similar determinants. Age, mean arterial pressure, and sex altogether explained 81.6 and 83.9% of the variance of PWV values measured with the Philips prototype and Complior device, respectively. When the two extremes of the three PWV values measured with the Philips prototype and the Complior device were investigated, the coefficients of variation were 8.26 and 3.26%, respectively. Compared with the Complior device, the Philips prototype had similar accuracy, determinants, and reproducibility in measuring PWV.

  18. [Pulse wave velocity of the leg minus that of the arm measured with a custom device correlates to the coronary calcium quantification].

    Science.gov (United States)

    Rico Martín, S; de Nicolás Jiménez, J M; Moyano Calvente, S L; Mogollón Jiménez, M V; Vega Fernández, J; Calderón García, J F; Bacaicoa Lopez de Sabando, M A; Tardio, M; Sánchez Muñoz-Torrero, J F

    2016-05-01

    The pulse wave velocity (PWV) in the great arteries is an indicator of vascular risk. Our objective was to identify the PWV index between the arms and legs that best correlates with the coronary calcium quantification (CCQ) and to compare it with other methods. Eight-one patients without vascular disease underwent the following measurements: CCQ; carotid intima-media thickness (IMT); carotid-femoral PWV (cfPWV), using COMPLIOR; and PWV in the arms and legs, with our own device (abiPWV, ankle brachial index PWV). The difference in PWVs between the leg and arm (l-a PWV) measured with abiPWV was the index that best correlated with CCQ (r=0.401, P<.001). The correlation between IMT and CCQ and between CF-PWV and CCQ were r=0.366, P=.001; and r=0.385, P=.001, respectively. For a CCQ score higher than 100 as a marker of significant coronary arteriosclerosis, the areas under the curve for l-a PWV, IMT and cfPWV were 0.721 (P=.002), 0.758 (P<.001) and 0.636 (P=.058), respectively. For patients without vascular disease, the l-a PWV measured with abiPWV appears to be the index that best correlates with the CCQ. This association is comparable to that between IMT and CCQ and between cfPWV and CCQ. The abiPWV is an easy-to-use device that can help improve vascular risk stratification. Copyright © 2016 Elsevier España, S.L.U. y Sociedad Española de Medicina Interna (SEMI). All rights reserved.

  19. Vascular aging processes accelerate following a cubic kinetic: pulse wave velocity as an objective counterpart that time, as we age, goes by faster

    Directory of Open Access Journals (Sweden)

    Gabutti L

    2018-02-01

    Full Text Available Luca Gabutti, Rosaria Del Giorno Department of Internal Medicine and Nephrology, Bellinzona Regional Hospital, Bellinzona, SwitzerlandArterial stiffness is a marker of vascular aging and is considered to be the most reliable parameter expressing, like an integral in mathematics, the cumulative consequences, on the vascular wall, of degenerative and adaptive changes occurring throughout life.1 The efficiency of the reparative processes, the cardiovascular risk factors (CVRF, and early life and genetic determinants, all play a relevant role.1 Among CVRF, the acceleration in arterial stiffness progression related to age is mainly influenced by hypertension.1 A pathological acceleration translates into the concept of early vascular aging, a concept that can be quantified calculating the gap between the subject’s chronological (estimated on the basis of the epidemiological data obtained in the normal population and effective vascular age.2 Data of subpopulations without active risk factors for accelerated vascular aging can be found mainly in three large epidemiological studies, performed respectively in Portugal,3 Argentina,4 and seven different European countries (Belgium, Czech Republic, France, Greece, Italy, the Netherlands, and UK gathered in a collaborative investigation.5 Those doing this secondary analysis were aware of the limitation related to the use of cross-sectional data to extrapolate longitudinal changes, and their aims were combining the abovementioned epidemiological data concerning the normal population to calculate with the highest possible accuracy 1 the age-related increase in acceleration of the pulse wave velocity (PWV and to estimate both 2 the age-specific relative amount of time equivalent to that necessary to progress 1 year in vascular age at 20, and 3 the cumulative relative age calculated in year equivalents. 

  20. Development and Validation of a Path Length Calculation for Carotid-Femoral Pulse Wave Velocity Measurement: A TASCFORCE, SUMMIT, and Caerphilly Collaborative Venture.

    Science.gov (United States)

    Weir-McCall, Jonathan R; Brown, Liam; Summersgill, Jennifer; Talarczyk, Piotr; Bonnici-Mallia, Michael; Chin, Sook C; Khan, Faisel; Struthers, Allan D; Sullivan, Frank; Colhoun, Helen M; Shore, Angela C; Aizawa, Kunihiko; Groop, Leif; Nilsson, Jan; Cockcroft, John R; McEniery, Carmel M; Wilkinson, Ian B; Ben-Shlomo, Yoav; Houston, J Graeme

    2018-05-01

    Current distance measurement techniques for pulse wave velocity (PWV) calculation are susceptible to intercenter variability. The aim of this study was to derive and validate a formula for this distance measurement. Based on carotid femoral distance in 1183 whole-body magnetic resonance angiograms, a formula was derived for calculating distance. This was compared with distance measurements in 128 whole-body magnetic resonance angiograms from a second study. The effects of recalculation of PWV using the new formula on association with risk factors, disease discrimination, and prediction of major adverse cardiovascular events were examined within 1242 participants from the multicenter SUMMIT study (Surrogate Markers of Micro- and Macrovascular Hard End-Points for Innovative Diabetes Tools) and 825 participants from the Caerphilly Prospective Study. The distance formula yielded a mean error of 7.8 mm (limits of agreement =-41.1 to 56.7 mm; P measurement, the distance formula did not change associations between PWV and age, blood pressure, or creatinine ( P accounting for differences in age, sex, and mean arterial pressure, intercenter differences in PWV persisted using the external distance measurement ( F =4.6; P =0.004), whereas there was a loss of between center difference using the distance formula ( F =1.4; P =0.24). PWV odds ratios for cardiovascular mortality remained the same using both the external distance measurement (1.14; 95% confidence interval, 1.06-1.24; P =0.001) and the distance formula (1.17; 95% confidence interval, 1.08-1.28; P measurement variability without impacting the diagnostic utility of carotid-femoral PWV. © 2018 The Authors.

  1. Traveling wave laser system

    International Nuclear Information System (INIS)

    Gregg, D.W.; Kidder, R.E.; Biehl, A.T.

    1975-01-01

    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.)

  2. Traveling wave laser system

    International Nuclear Information System (INIS)

    Gregg, D.W.; Kidder, R.E.; Biehl, A.T.

    1975-01-01

    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.)

  3. 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.

  4. Aortic pulse wave velocity and HeartSCORE: improving cardiovascular risk stratification. a sub-analysis of the EDIVA (Estudo de DIstensibilidade VAscular) project.

    Science.gov (United States)

    Pereira, T; Maldonado, J; Polónia, J; Silva, J A; Morais, J; Rodrigues, T; Marques, M

    2014-04-01

    HeartSCORE is a tool for assessing cardiovascular risk, basing its estimates on the relative weight of conventional cardiovascular risk factors. However, new markers of cardiovascular risk have been identified, such as aortic pulse wave velocity (PWV). The purpose of this study was to evaluate to what extent the incorporation of PWV in HeartSCORE increases its discriminative power of major cardiovascular events (MACE). This study is a sub-analysis of the EDIVA project, which is a prospective cohort, multicenter and observational study involving 2200 individuals of Portuguese nationality (1290 men and 910 women) aged between 18 and 91 years (mean 46.33 ± 13.76 years), with annual measurements of PWV (Complior). Only participants above 35 years old were included in the present re-analysis, resulting in a population of 1709 participants. All MACE - death, cerebrovascular accident, coronary accidents (coronary heart disease), peripheral arterial disease and renal failure - were recorded. During a mean follow-up period of 21.42 ± 10.76 months, there were 47 non-fatal MACE (2.1% of the sample). Cardiovascular risk was estimated in all patients based on the HeartSCORE risk factors. For the analysis, the refitted HeartSCORE and PWV were divided into three risk categories. The event-free survival at 2 years was 98.6%, 98.0% and 96.1%, respectively in the low-, intermediate- and high-risk categories of HeartSCORE (log-rank p factor model. The C statistics improved from 0.69 to 0.78 (adding PWV, p = 0.005). The net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were also determined, and indicated further evidence of improvements in discrimination of the outcome when including PWV in the risk-factor model (NRI = 0.265; IDI = 0.012). The results clearly illustrate the benefits of integrating PWV in the risk assessment strategies, as advocated by HeartSCORE, insofar as it contributes to a better discriminative capacity of global

  5. EVOLUTION OF FAST MAGNETOACOUSTIC PULSES IN RANDOMLY STRUCTURED CORONAL PLASMAS

    International Nuclear Information System (INIS)

    Yuan, D.; Li, B.; Pascoe, D. J.; Nakariakov, V. M.; Keppens, R.

    2015-01-01

    We investigate the evolution of fast magnetoacoustic pulses in randomly structured plasmas, in the context of large-scale propagating waves in the solar atmosphere. We perform one-dimensional numerical simulations of fast wave pulses propagating perpendicular to a constant magnetic field in a low-β plasma with a random density profile across the field. Both linear and nonlinear regimes are considered. We study how the evolution of the pulse amplitude and width depends on their initial values and the parameters of the random structuring. Acting as a dispersive medium, a randomly structured plasma causes amplitude attenuation and width broadening of the fast wave pulses. After the passage of the main pulse, secondary propagating and standing fast waves appear. Width evolution of both linear and nonlinear pulses can be well approximated by linear functions; however, narrow pulses may have zero or negative broadening. This arises because narrow pulses are prone to splitting, while broad pulses usually deviate less from their initial Gaussian shape and form ripple structures on top of the main pulse. Linear pulses decay at an almost constant rate, while nonlinear pulses decay exponentially. A pulse interacts most efficiently with a random medium with a correlation length of about half of the initial pulse width. This detailed model of fast wave pulses propagating in highly structured media substantiates the interpretation of EIT waves as fast magnetoacoustic waves. Evolution of a fast pulse provides us with a novel method to diagnose the sub-resolution filamentation of the solar atmosphere

  6. Study on the cutting quality by rectangular pulse wave of the CO sub 2 laser. CO sub 2 laser no kukei pulse hakei ni yoru setsudan hinshitsu no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Kanaoka, M. (Mitsubishi Electric Corporation, Tokyo (Japan))

    1992-05-20

    The paper studies effects of laser power parameters on processing quality in cutting metal by the use of rectangular pulse waveform formed by the triaxial cross flow resonator. As a result, the heat affected zone appearing around the kerf expands from the upper part to the lower part, and by increasing pulse peak power the width of the heat affected zone from the central part of board thickness to the lower part lessens. Further, by lowering pulse frequency, the width of the heat affected zone appearing around the kerf from the central part of board thickness to the lower part lessens. Also, by lowering frequency, an energy absortion rate of the workpiece to be processed decreases. Cutting surface roughness is affected by pulse peak power, and the high the peak value is, the better the surface roughness is improved. In addition, the surface roughmess is affected by pulse frequency, and the higher the frequency is, the better the surface roughness is improved. 6 refs., 15 figs.

  7. Patterns of digital volume pulse waveform and pulse transit time in ...

    African Journals Online (AJOL)

    In this study the digital volume pulse wave and the pulse transit time of the thumb and big toe were analyzed in young and older subjects some of whom were hypertensive. We aimed to study the components and patterns of the pulse waveform and the pulse transit time and how they might change. Material and Methods: ...

  8. Estimación de la velocidad de propagación aórtica basada en el análisis de la onda de pulso radial Velocity estimation of aortic propagation based on radial pulse wave analysis

    Directory of Open Access Journals (Sweden)

    Fernando Clara

    2011-06-01

    Full Text Available Se exploró la posibilidad de utilizar la morfología del registro de onda de pulso radial obtenida mediante un transductor de movimiento para evaluar la velocidad de propagación aórtica. Se efectuó el registro de onda de pulso en arteria radial mediante un transductor apoyado sobre la zona de palpación del pulso, sobre un conjunto de 167 voluntarios varones sanos normotensos de edades comprendidas entre la 2ª y la 7ª década. Se identificó en los registros la onda reflejada y se definió un coeficiente de velocidad como el cociente entre la talla del individuo y el tiempo transcurrido entre el máximo de la onda sistólica y el instante de llegada de dicha onda. Se halló que en los normotensos el coeficiente mencionado aumentó en forma lineal con la edad, en una proporción similar al aumento de velocidad de propagación aórtica medido con otros métodos. Se repitió el procedimiento en otro conjunto de 125 varones hipertensos sin otros factores de riesgo, de edades entre la 3ª y la 7ª década, hallándose valores similares a los normotensos solamente en la 3ª década, a partir de la cual se registró un incremento significativo de dicho índice. Tales hallazgos sustentan la factibilidad de utilizar tal tipo de registros para evaluar indirectamente la velocidad de propagación junto con el índice de aumentación, un parámetro habitualmente utilizado en el análisis de onda de pulso.We analyzed the possibility of using the radial pulse wave morphology, obtained by a movement transducer, to evaluate the aortic pulse wave velocity. The radial pulse wave signals were obtained by using a transducer, located on the pulse palpation area, in 167 healthy normotensive male volunteers, ages 20 to 70. The reflected wave was identified in every case. Also, a speed coefficient was defined as the ratio between the individual's height and the time between the maximum systolic wave and the arrival time of the reflected wave. We found that the

  9. 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

  10. 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.

    Science.gov (United States)

    Gómez-Marcos, Manuel A; Recio-Rodríguez, José I; Rodríguez-Sánchez, Emiliano; Castaño-Sánchez, Yolanda; de Cabo-Laso, Angela; Sánchez-Salgado, Benigna; Rodríguez-Martín, Carmela; Castaño-Sánchez, Carmen; Gómez-Sánchez, Leticia; García-Ortiz, Luis

    2010-03-18

    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. 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. The study will be carried out in the urban primary care setting. 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. 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 medication used for diabetes, arterial hypertension and hyperlipidemia will be registered, together

  11. Problems in nonlinear acoustics: Pulsed finite amplitude sound beams, nonlinear acoustic wave propagation in a liquid layer, nonlinear effects in asymmetric cylindrical sound beams, effects of absorption on the interaction of sound beams, and parametric receiving arrays

    Science.gov (United States)

    Hamilton, Mark F.

    1990-12-01

    This report discusses five projects all of which involve basic theoretical research in nonlinear acoustics: (1) pulsed finite amplitude sound beams are studied with a recently developed time domain computer algorithm that solves the KZK nonlinear parabolic wave equation; (2) nonlinear acoustic wave propagation in a liquid layer is a study of harmonic generation and acoustic soliton information in a liquid between a rigid and a free surface; (3) nonlinear effects in asymmetric cylindrical sound beams is a study of source asymmetries and scattering of sound by sound at high intensity; (4) effects of absorption on the interaction of sound beams is a completed study of the role of absorption in second harmonic generation and scattering of sound by sound; and (5) parametric receiving arrays is a completed study of parametric reception in a reverberant environment.

  12. Validity of the Water Hammer Formula for Determining Regional Aortic Pulse Wave Velocity: Comparison of One-Point and Two-Point (Foot-to-Foot) Measurements Using a Multisensor Catheter in Human.

    Science.gov (United States)

    Hanya, Shizuo

    2013-01-01

    Lack of high-fidelity simultaneous measurements of pressure and flow velocity in the aorta has impeded the direct validation of the water-hammer formula for estimating regional aortic pulse wave velocity (AO-PWV1) and has restricted the study of the change of beat-to-beat AO-PWV1 under varying physiological conditions in man. Aortic pulse wave velocity was derived using two methods in 15 normotensive subjects: 1) the conventional two-point (foot-to-foot) method (AO-PWV2) and 2) a one-point method (AO-PWV1) in which the pressure velocity-loop (PV-loop) was analyzed based on the water hammer formula using simultaneous measurements of flow velocity (Vm) and pressure (Pm) at the same site in the proximal aorta using a multisensor catheter. AO-PWV1 was calculated from the slope of the linear regression line between Pm and Vm where wave reflection (Pb) was at a minimum in early systole in the PV-loop using the water hammer formula, PWV1 = (Pm/Vm)/ρ, where ρ is the blood density. AO-PWV2 was calculated using the conventional two-point measurement method as the distance/traveling time of the wave between 2 sites for measuring P in the proximal aorta. Beat-to-beat alterations of AO-PWV1 in relationship to aortic pressure and linearity of the initial part of the PV-loop during a Valsalva maneuver were also assessed in one subject. The initial part of the loop became steeper in association with the beat-to-beat increase in diastolic pressure in phase 4 during the Valsalva maneuver. The linearity of the initial part of the PV-loop was maintained consistently during the maneuver. Flow velocity vs. pressure in the proximal aorta was highly linear during early systole, with Pearson's coefficients ranging from 0.9954 to 0.9998. The average values of AO-PWV1 and AO-PWV2 were 6.3 ± 1.2 and 6.7 ± 1.3 m/s, respectively. The regression line of AO-PWV1 on AO-PWV2 was y = 0.95x + 0.68 (r = 0.93, p <0.001). This study concluded that the water-hammer formula (one-point method) provides

  13. Spin wave and percolation studies in epitaxial La{sub 2/3}Sr{sub 1/3}MnO{sub 3} thin films grown by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ettayfi, A. [LPMMAT, Faculté des Sciences Ain chock, Université Hassan II de Casablanca, B.P. 5366 Casablanca (Morocco); Moubah, R., E-mail: reda.moubah@hotmail.fr [LPMMAT, Faculté des Sciences Ain chock, Université Hassan II de Casablanca, B.P. 5366 Casablanca (Morocco); Hlil, E.K. [Institut Néel, CNRS, Université Joseph Fourier, BP 166, 38042 Grenoble Cedex 9 (France); Colis, S.; Lenertz, M.; Dinia, A. [Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), UMR 7504 UDS-CNRS (UDS-ECPM), 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2 (France); Lassri, H. [LPMMAT, Faculté des Sciences Ain chock, Université Hassan II de Casablanca, B.P. 5366 Casablanca (Morocco)

    2016-07-01

    We investigate the magnetic and transport properties of high quality La{sub 2/3}Sr{sub 1/3}MnO{sub 3} 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. - Highlights: • The magnetic and transport properties of epitaxial La{sub 2/3}Sr{sub 1/3}MnO{sub 3} thin films are investigated. • The M(T) curve was modeled at low temperature, and several magnetic parameters were obtained using spin wave theory. • The percolation theory was used to simulate ρ(T) in both the ferromagnetic and paramagnetic phases.

  14. Relationships between lifestyle patterns and cardio-renal-metabolic parameters in patients with type 2 diabetes mellitus: A cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Takeshi Ogihara

    Full Text Available While individuals tend to show accumulation of certain lifestyle patterns, the effect of such patterns in real daily life on cardio-renal-metabolic parameters remains largely unknown. This study aimed to assess clustering of lifestyle patterns and investigate the relationships between such patterns and cardio-renal-metabolic parameters.The study participants were 726 Japanese type 2 diabetes mellitus (T2DM outpatients free of history of cardiovascular diseases. The relationship between lifestyle patterns and cardio-renal-metabolic parameters was investigated by linear and logistic regression analyses.Factor analysis identified three lifestyle patterns. Subjects characterized by evening type, poor sleep quality and depressive status (type 1 pattern had high levels of HbA1c, alanine aminotransferase and albuminuria. Subjects characterized by high consumption of food, alcohol and cigarettes (type 2 pattern had high levels of γ-glutamyl transpeptidase, triglycerides, HDL-cholesterol, blood pressure, and brachial-ankle pulse wave velocity. Subjects characterized by high physical activity (type 3 pattern had low uric acid and mild elevation of alanine aminotransferase and aspartate aminotransferase. In multivariate regression analysis adjusted by age, gender and BMI, type 1 pattern was associated with higher HbA1c levels, systolic BP and brachial-ankle pulse wave velocity. Type 2 pattern was associated with higher HDL-cholesterol levels, triglycerides, aspartate aminotransferase, ɤ- glutamyl transpeptidase levels, and diastolic BP.The study identified three lifestyle patterns that were associated with distinct cardio-metabolic-renal parameters in T2DM patients.UMIN000010932.

  15. Muscle mass decline, arterial stiffness, white matter hyperintensity, and cognitive impairment: Japan Shimanami Health Promoting Program study.

    Science.gov (United States)

    Kohara, Katsuhiko; Okada, Yoko; Ochi, Masayuki; Ohara, Maya; Nagai, Tokihisa; Tabara, Yasuharu; Igase, Michiya

    2017-08-01

    There is a close association between frailty and cognitive impairment. However, the underlying contribution of sarcopenia to the development of cognitive impairment is unclear. We investigated the possible association between muscle mass decline and cognitive impairment in a cross-sectional study of 1518 subjects aged 55 years or above. We also evaluated arterial stiffness and white matter hyperintensities (WMHs) as possible underlying mechanisms for this association. Two sarcopenic indices were measured: thigh muscle cross-sectional area (CSA; calculated by computed tomography) and skeletal muscle mass (bioelectric impedance). Muscle mass decline was defined as either the bottom 10% or 20% of participants for each sex. Cognitive function was assessed using the Touch Panel-type Dementia Assessment Scale, and brachial-ankle pulse wave velocity was measured as an index of arterial stiffness. Both sarcopenic indices were modestly but significantly associated with brachial-ankle pulse wave velocity in male and female subjects. The presence of WMHs was significantly associated with low thigh muscle CSA in men and with low skeletal muscle mass in women. The Touch Panel-type Dementia Assessment Scale score was modestly but significantly and positively associated with thigh muscle CSA in men and skeletal muscle mass in women. Muscle mass decline in the bottom 10% of participants on both sarcopenic indices was significantly and independently related to cognitive impairment in women. Lower sarcopenic indices are significantly related to lower cognitive scores. Arterial stiffness and WMHs could account, at least in part, for this association. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  16. Pulse Generator

    Science.gov (United States)

    Greer, Lawrence (Inventor)

    2017-01-01

    An apparatus and a computer-implemented method for generating pulses synchronized to a rising edge of a tachometer signal from rotating machinery are disclosed. For example, in one embodiment, a pulse state machine may be configured to generate a plurality of pulses, and a period state machine may be configured to determine a period for each of the plurality of pulses.

  17. Influence of immune-mediated hemolytic anemia on flow velocities in the portal vein and caudal vena cava measured by use of pulsed-wave Doppler ultrasonography in dogs.

    Science.gov (United States)

    Smith, Rachel Policelli; Koenigshof, Amy M; Smith, Daniel J; Strom, Phillip R; Nelson, Nathan C

    2018-05-01

    OBJECTIVE To compare blood flow velocities of the portal vein (PV) and caudal vena cava (CVC) measured by use of pulsed-wave Doppler ultrasonography in clinically normal dogs and dogs with primary immune-mediated hemolytic anemia (IMHA). ANIMALS 11 client-owned dogs admitted to a veterinary teaching hospital for management of primary IMHA and 21 staff- or student-owned clinically normal dogs. PROCEDURES Flow velocities in the PV and CVC at the porta hepatis were evaluated in conscious unsedated dogs with concurrent ECG monitoring; evaluations were performed before dogs with IMHA received heparin or blood transfusions. Three measurements of peak velocity at end expiration were obtained for each vessel, and the mean was calculated. Results were compared between IMHA and control groups. RESULTS Mean ± SD blood flow velocity in the CVC differed between control (63.0 ± 18.6 cm/s) and IMHA (104 ± 36.9 cm/s) groups. Variance in dogs with IMHA was significantly greater than that for the clinically normal dogs. No significant difference in blood flow velocity in the PV was detected between IMHA and control dogs. CONCLUSIONS AND CLINICAL RELEVANCE Higher blood flow velocities were detected by use of pulsed-wave Doppler ultrasonography in the CVC of dogs with naturally occurring IMHA and may be used to predict anemia in patients suspected of having IMHA.

  18. Efficient terahertz wave generation from GaP crystals pumped by chirp-controlled pulses from femtosecond photonic crystal fiber amplifier

    International Nuclear Information System (INIS)

    Li, Jiang; Shi, Junkai; Xu, Baozhong; Xing, Qirong; Wang, Chingyue; Chai, Lu; Liu, Bowen; Hu, Minglie; Li, Yanfeng; Fedotov, Andrey B.; Zheltikov, Aleksei M.

    2014-01-01

    A chirp-tunable femtosecond 10 W, 42 MHz photonic-crystal-fiber oscillator-amplifier system that is capable of delivering sub-60 fs light pulses at 1040 nm is used to demonstrate high-efficiency terahertz radiation generation via optical rectification in GaP crystals only a few millimeters in length. The optimization of the chirp of the fiber-laser pulses is shown to radically enhance the terahertz output, indicating one possible way to more efficiently use these extended nonlinear crystals in compact fiber-pumped terahertz radiation sources

  19. ON THE PAPER BY L.S. KONEV ET AL. “SIMULATING EVOLUTION OF FORWARD AND BACKWARD WAVES OF FEW-CYCLE PULSES PROPAGATING IN AN OPTICAL WAVEGUIDE WITH DISPERSION AND CUBIC NONLINEARITY OF ELECTRONIC AND ELECTRONIC-VIBRATION NATURE”

    Directory of Open Access Journals (Sweden)

    N. N. Rosanov

    2015-09-01

    Full Text Available Problem statement ill-posedness in the paper by L.S. Konev et al. devoted to formation of backward wave at short laser pulse propagation in nonlinear media or fibers is specified. It is inconceivable in the correct problem statement to consider the radiation field at the medium entrance as a given function of time due to generation of backward wave in the medium, when the backward wave characteristics are target values. The proper evolution variable is time, and it is convenient to use the adopted finite-difference time-domain (FDTD method for backward wave calculation.

  20. Development of a Cardiovascular Simulator for Studying Pulse Diagnosis Mechanisms

    Directory of Open Access Journals (Sweden)

    Min Jang

    2017-01-01

    Full Text Available This research was undertaken to develop a cardiovascular simulator for use in the study of pulse diagnosis. The physical (i.e., pulse wave transmission and reflection and physiological (i.e., systolic and diastolic pressure, pulse pressure, and mean pressure characteristics of the radial pulse wave were reproduced by our simulator. The simulator consisted of an arterial component and a pulse-generating component. Computer simulation was used to simplify the arterial component while maintaining the elastic modulus and artery size. To improve the reflected wave characteristics, a palmar arch was incorporated within the simulator. The simulated radial pulse showed good agreement with clinical data.

  1. Two-photon stimulated emission and pulse amplification

    International Nuclear Information System (INIS)

    Yuen, H.P.

    1975-01-01

    Threshold conditions are given for the sustained operation of standing-wave and long-pulse traveling-wave two-photon lasers. Pulse shortening in long-pulse two-photon amplification, a behavior absent in the one-photon case, is also demonstrated analytically. (U.S.)

  2. Electromagnetic or other directed energy pulse launcher

    Science.gov (United States)

    Ziolkowski, Richard W.

    1990-01-01

    The physical realization of new solutions of wave propagation equations, such as Maxwell's equations and the scaler wave equation, produces localized pulses of wave energy such as electromagnetic or acoustic energy which propagate over long distances without divergence. The pulses are produced by driving each element of an array of radiating sources with a particular drive function so that the resultant localized packet of energy closely approximates the exact solutions and behaves the same.

  3. STUCTURE OF PULSED BED

    Directory of Open Access Journals (Sweden)

    I. A. Bokun

    2014-01-01

    Full Text Available The structure of pulsed layer is proposed which can be suggested as a state of particulates that is blown by intermittent gas flow with speed which has the force to start material moving. Layer during one cycle is in a suspension, falling down and immobile state resulting in changes of particles arrangement as well as ways of gas flowing through layer. Moreover, it allows carrying out effective interphase heat exchange even adamant real granulation.The process of formation of impact flows is considered aw well as their influence on formation of air bubbles in pulsed layer. At startup of air blast the balance between the force of hydro-dynamic resistance is broken, on one side, and forces of gravity, particles inertia and their links with walls on the other side. The layer is transferred in the state of pulsed pseudo-fluidization, and presents gas-disperse mixture, inside of which impulse of pressure increasing is spreading to all sides as pressure waves (compression. These waves are the sources of impact flows’ formation, the force of which is two times more than during the stationary flow.The waves of pressure are divided into weak and strong ones depending on movement velocity within gas-disperse system. Weak waves are moving with a sound speed and strong ones in active phase of pulsed layer are moving over the speed of sound limit within gas-disperse system. The peculiarity of strong wave is that parameters of system (pressure, density and others are changing in discrete steps.The article describes the regime of layer’s falling down in the passive stage of cycle, which begins after finishing of gas impulse action. And suspension layer of moving up granular material is transferred in the state of falling resulting in change of the layer structure.

  4. Study on the Depth, Rate, Shape, and Strength of Pulse with Cardiovascular Simulator

    Directory of Open Access Journals (Sweden)

    Ju-Yeon Lee

    2017-01-01

    Full Text Available Pulse diagnosis is important in oriental medicine. The purpose of this study is explaining the mechanisms of pulse with a cardiovascular simulator. The simulator is comprised of the pulse generating part, the vessel part, and the measurement part. The pulse generating part was composed of motor, slider-crank mechanism, and piston pump. The vessel part, which was composed with the aorta and a radial artery, was fabricated with silicon to implement pulse wave propagation. The pulse parameters, such as the depth, rate, shape, and strength, were simulated. With changing the mean pressure, the floating pulse and the sunken pulse were generated. The change of heart rate generated the slow pulse and the rapid pulse. The control of the superposition time of the reflected wave generated the string-like pulse and the slippery pulse. With changing the pulse pressure, the vacuous pulse and the replete pulse were generated. The generated pulses showed good agreements with the typical pulses.

  5. 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

    We regard the rovibrational wave packet dynamics of NaI in a static electric field after femtosecond excitation to its first electronically excited state. The following quasibound nuclear wave packet motion is accompanied by a bonding situation changing from covalent to ionic. At times when...... 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...

  6. Time-resolved processes in a pulsed electrical discharge in water generated with shock wave assistance in a plate-to-plate configuration

    Czech Academy of Sciences Publication Activity Database

    Stelmashuk, Vitaliy

    2014-01-01

    Roč. 47, č. 49 (2014), s. 495204-495204 ISSN 0022-3727 Institutional support: RVO:61389021 Keywords : underwater discharge * streamers * spark * cavitation bubble * shock wave Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.721, year: 2014 http://iopscience.iop.org/0022-3727/47/49/495204/pdf/0022-3727_47_49_495204.pdf

  7. [Pilot study of echocardiographic studies using color- and pulsed-wave spectral Doppler methods in blue-crowned amazons (Amazona ventralis) and blue-fronted amazons (Amazona a. aestiva)].

    Science.gov (United States)

    Pees, M; Straub, J; Schumacher, J; Gompf, R; Krautwald-Junghanns, M E

    2005-02-01

    Colour-flow and pulsed-wave spectral Doppler echocardiography was performed on 6 healthy, adult Hispaniolan amazon parrots (Amazona ventralis) and 6 blue-fronted amazon parrots (Amazona a. aestiva) to establish normal reference values. Birds were anesthetized with isoflurane in oxygen and placed in dorsal recumbency. An electrocardiogram was recorded continuously and birds were imaged with a micro-phased-array scanner with a frequency of 7.0 MHz. After assessment of cardiac function in 2-D-echocardiography, blood flow across the left and the right atrioventricular valve and across the aortic valve was determined using color-flow and pulsed-wave spectral Doppler echocardiography. Diastolic inflow (mean value +/- standard deviation) into the left ventricle was 0.17 +/- 0.02 m/s (Hispaniolan amazons) and 0.18 +/- 0.03 m/s (Blue fronted amazons). Diastolic inflow into the right ventricle was 0.22 +/- 0.05 m/s (Hispaniolan amazons) and 0.22 +/- 0.04 m/s (Blue fronted amazons). Velocity across the aortic valve was 0.84 +/- 0.07 m/s (Hispaniolan amazons) and 0.83 +/- 0.08 m/s (Blue fronted amazons). Systolic pulmonary flow could not be detected in any of the birds in this study. No significant differences were evident between the two species examined. Results of this study indicate that Doppler echocardiography is a promising technique to determine blood flow in the avian heart. Further studies in other avian species are needed to establish reference values for assessment of cardiac function in diseased birds.

  8. Efficient continuous-wave and passively Q-switched pulse laser operations in a diffusion-bonded sapphire/Er:Yb:YAl3(BO3)4/sapphire composite crystal around 1.55 μm.

    Science.gov (United States)

    Chen, Yujin; Lin, Yanfu; Huang, Jianhua; Gong, Xinghong; Luo, Zundu; Huang, Yidong

    2018-01-08

    A composite crystal consisting of a 1.5-mm-thick Er:Yb:YAl 3 (BO 3 ) 4 crystal between two 1.2-mm-thick sapphire crystals was fabricated by the thermal diffusion bonding technique. Compared with a lone Er:Yb:YAl 3 (BO 3 ) 4 crystal measured under the identical experimental conditions, higher laser performances were demonstrated in the sapphire/Er:Yb:YAl 3 (BO 3 ) 4 /sapphire composite crystal due to the reduction of the thermal effects. End-pumped by a 976 nm laser diode in a hemispherical cavity, a 1.55 μm continuous-wave laser with a maximum output power of 1.75 W and a slope efficiency of 36% was obtained in the composite crystal when the incident pump power was 6.54 W. Passively Q-switched by a Co 2+ :MgAl 2 O 4 crystal, a 1.52 μm pulse laser with energy of 10 μJ and repetition frequency of 105 kHz was also realized in the composite crystal. Pulse width was 315 ns. The results show that the sapphire/Er:Yb:YAl 3 (BO 3 ) 4 /sapphire composite crystal is an excellent active element for 1.55 μm laser.

  9. Analysis of pulsatile retinal movements by spectral-domain low-coherence interferometry: influence of age and glaucoma on the pulse wave.

    Directory of Open Access Journals (Sweden)

    Carolyne Dion

    Full Text Available Recent studies have shown that ocular hemodynamics and eye tissue biomechanical properties play an important role in the pathophysiology of glaucoma. Nevertheless, better, non-invasive methods to assess these characteristics in vivo are essential for a thorough understanding of degenerative mechanisms. Here, we propose to measure ocular tissue movements induced by cardiac pulsations and study the ocular pulse waveform as an indicator of tissue compliance. Using a novel, low-cost and non-invasive device based on spectral-domain low coherence interferometry (SD-LCI, we demonstrate the potential of this technique to differentiate ocular hemodynamic and biomechanical properties. We measured the axial movement of the retina driven by the pulsatile ocular blood flow in 11 young healthy individuals, 12 older healthy individuals and 15 older treated glaucoma patients using our custom-made SD-OCT apparatus. The cardiac pulse was simultaneously measured through the use of an oximeter to allow comparison. Spectral components up to the second harmonic were obtained and analyzed. For the different cohorts, we computed a few parameters that characterize the three groups of individuals by analyzing the movement of the retinal tissue at two locations, using this simple, low-cost interferometric device. Our pilot study indicates that spectral analysis of the fundus pulsation has potential for the study of ocular biomechanical and vascular properties, as well as for the study of ocular disease.

  10. Compliance of the normal-sized aorta in adolescents with Marfan syndrome: comparison of MR measurements of aortic distensibility and pulse wave velocity; Compliance der morphologisch unauffaelligen Aorta bei Jugendlichen mit Marfan Syndrom: Vergleich von MR-Messungen der aortalen Dehnbarkeit und der Pulswellengeschwindigkeit

    Energy Technology Data Exchange (ETDEWEB)

    Eichhorn, J.G.; Ruediger, H.J.; Gorenflo, M.; Khalil, M.; Ulmer, H. [Universitaetskinderklinik Heidelberg (Germany). Kardiologie; Krissak, R.; Kauczor, H.U. [Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany). Radiologie; Ley, S. [Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany). Radiologie; Universitaetsklinik Heidelberg (Germany). Paediatrische Kardiologie; Arnold, R. [Universitaetskinderklinik Heidelberg (Germany). Kardiologie; Universitaetskinderklinik Freiburg (Germany). Paediatrische Kardiologie; Boese, J. [Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany). Medizinische Physik in der Radiologie; Siemens AG, Medical Solutions, Forchheim (Germany). Angiography, Fluoroscopic and Radiographic Systems; Krug, R. [Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany). Medizinische Physik in der Radiologie; Fink, C. [Medizinische Fakultaet Mannheim der Univ. Heidelberg, Mannheim (Germany). Inst. fuer Klinische Radiologie

    2007-08-15

    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 ({chi}{sup 2}-test, p = 0.0002) using an age-related non-linear regression analysis. The related aortic compliance was significantly decreased ({chi}{sup 2}-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.)

  11. Dispersion - does it degrade a pulse envelope

    International Nuclear Information System (INIS)

    Deighton, M.O.

    1985-01-01

    In hostile environments, transmitting information as ultrasonic Lamb wave pulses has advantages, since the stainless steel strip serving as a waveguide is very durable. Besides attenuation, velocity dispersion (inherent in Lamb waves) can be important even in fairly short guides. Theory shows that unlimited propagation of a pulsed r.f. envelope is possible, even with dispersion present. The constant group velocity needed would favour asub(o)-mode pulses over other modes, provided ordinary attenuation is small. An approximate formula indicates the useful range of a pulse, when group velocity does vary. (author)

  12. Mono-energetic ion beam acceleration in solitary waves during relativistic transparency using high-contrast circularly polarized short-pulse laser and nanoscale targets

    International Nuclear Information System (INIS)

    Yin, L.; Albright, B. J.; Bowers, K. J.; Shah, R. C.; Palaniyappan, S.; Fernandez, J. C.; Jung, D.; Hegelich, B. M.

    2011-01-01

    In recent experiments at the Trident laser facility, quasi-monoenergetic ion beams have been obtained from the interaction of an ultraintense, circularly polarized laser with a diamond-like carbon target of nm-scale thickness under conditions of ultrahigh laser pulse contrast. Kinetic simulations of this experiment under realistic laser and plasma conditions show that relativistic transparency occurs before significant radiation pressure acceleration and that the main ion acceleration occurs after the onset of relativistic transparency. Associated with this transition are a period of intense ion acceleration and the generation of a new class of ion solitons that naturally give rise to quasi-monoenergetic ion beams. An analytic theory has been derived for the properties of these solitons that reproduces the behavior observed in kinetic simulations and the experiments.

  13. Rapid testing of pulse transformers

    Science.gov (United States)

    Grillo, J.

    1980-01-01

    Quality-control testing of pulse transformers is speeded up by method for determining rise time and droop. Instead of using oscilloscope and square-wave generator to measure these characteristics directly, method uses voltmeter and sine-wave generator to measure them indirectly in about one-tenth time. Droop and rise time are determined by measuring input/output voltage ratio at just four frequencies.

  14. Determination of biogenic amines in chocolate by ion chromatographic separation and pulsed integrated amperometric detection with implemented wave-form at Au disposable electrode.

    Science.gov (United States)

    Pastore, Paolo; Favaro, Gabriella; Badocco, Denis; Tapparo, Andrea; Cavalli, Silvano; Saccani, Giovanna

    2005-12-09

    A rapid and selective cation exchange chromatographic method coupled to integrated pulsed amperometric detection (PAD) has been developed to quantify biogenic amines in chocolate. The method is based on gradient elution of aqueous methanesulfonic acid with post column addition of strong base to obtain suitable conditions for amperometric detection. A potential waveform able to keep long time performance of the Au disposable electrode was set up. Total analysis time is less than 20min. Concentration levels of dopamine, serotonin, tyramine, histamine and 2-phenylethylamine were measured, after extraction with perchloric acid from 2g samples previously defatted twice with petroleum ether. The method was used to determine the analytes in chocolate real matrices and their quantification was made with standard addition method. Only dopamine, histamine and serotonin were found in the analysed real samples. Repeatabilities of their signals, computed on their amounts in the real samples, were 5% for all of them. Repeatabilities of tyramine and phenethylamine were relative to standard additions to real samples (close to 1mg/l in the extract) and were 7 and 3%, respectively. Detection limits were computed with the 3s of the baseline noise combined with the calibration plot regression parameters. They were satisfactorily low for all amines: 3mg/kg for dopamine, 2mg/kg for tyramine, 1mg/kg for histamine, 2mg/kg for serotonin, 3mg/kg for 2-phenylethylamine.

  15. Modeling digital pulse waveforms by solving one-dimensional Navier-stokes equations.

    Science.gov (United States)

    Fedotov, Aleksandr A; Akulova, Anna S; Akulov, Sergey A

    2016-08-01

    Mathematical modeling for composition distal arterial pulse wave in the blood vessels of the upper limbs was considered. Formation of distal arterial pulse wave is represented as a composition of forward and reflected pulse waves propagating along the arterial vessels. The formal analogy between pulse waves propagation along the human arterial system and the propagation of electrical oscillations in electrical transmission lines with distributed parameters was proposed. Dependencies of pulse wave propagation along the human arterial system were obtained by solving the one-dimensional Navier-Stokes equations for a few special cases.

  16. Nitrogen ligation to manganese in the photosynthetic oxygen-evolving complex: Continuous-wave and pulsed EPR studies of Photosystem II particles containing 14N or 15N

    International Nuclear Information System (INIS)

    DeRose, V.J.; Yachandra, V.K.; McDermott, A.E.; Britt, R.D.; Sauer, K.; Klein, M.P.

    1991-01-01

    The possibility of nitrogen ligation to the Mn in the oxygen-evolving complex from photosystem II was investigated with electron paramagnetic resonance (EPR) and electron spin echo envelope modulation (ESEEM) spectroscopies using 14 N- and 15 N-labeled preparations. Oxygen-evolving preparations were isolated from a thermophilic cyanobacterium, Synechococcus sp., grown on a medium containing either 14 NO 3 - or 15 NO - 3 as the sole source of nitrogen. The substructure on the multiline EPR signal, which arises from Mn in the S 2 state of the enzyme, was measured with continuous-wave EPR. No changes were detected in the substructure peak positions upon substitution of 15 N for 14 N, indicating that this substructure is not due to superhyperfine coupling from nitrogen ligands. To detect potential nitrogen ligands with superhyperfine couplings of lesser magnitude than could be observed with conventional EPR methods, electron spin-echo envelope modulation experiments were also performed on the multiline EPR signal. The Fourier transform of the light-minus-dark time domain ESEEM data shows a peak at 4.8 MHz in 14 N samples which is absent upon substitution with 15 N. This gives unambiguous evidence for weak hyperfine coupling of nitrogen to the Mn of the oxygen-evolving complex. Possible origins of this nitrogen interaction are discussed

  17. Fast Heat Pulse Propagation by Turbulence Spreading

    DEFF Research Database (Denmark)

    Naulin, Volker; Juul Rasmussen, Jens; Mantica, Paola

    2009-01-01

    The propagation of a cold pulse initiated by edge cooling in JET is compared to propagation of the heat wave originating from a modulation of the heating source roughly at mid radius. It is found that the propagation of the cold pulse is by far faster than what could be predicted on the basis of ...

  18. Aortic-Radial Pulse Wave Velocity Ratio in End-stage Renal Disease Patients: Association with Age, Body Tissue Hydration Status, Renal Failure Etiology and Five Years of Hemodialysis.

    Science.gov (United States)

    Bia, Daniel; Valtuille, Rodolfo; Galli, Cintia; Wray, Sandra; Armentano, Ricardo; Zócalo, Yanina; Cabrera-Fischer, Edmundo

    2017-03-01

    The etiology of the end-stage renal disease (ESRD) and the hydration status may be involved in the arterial stiffening process observed in hemodialyzed patients. The ratio between carotid-femoral and carotid-radial pulse wave velocity (PWV ratio) was recently proposed to characterize the patient-specific stiffening process. to analyze: (1) the PWV-ratio in healthy and hemodialyzed subjects, analyzing potential changes associated to etiologies of the ESRD, (2) the PWV-ratio and hydration status using multiple-frequency bioimpedance and, (3) the effects of hemodialysis on PWV-ratio in a 5-year follow-up. PWV-ratio was evaluated in 151 patients differentiated by the pathology determining their ESRD. Total body fluid (TBF), intra and extra cellular fluid (ICF, ECF) were measured in 65 of these patients using bioelectrical-impedance. The association between arterial, hemodynamic or fluid parameters was analyzed. PWV-ratio was evaluated in a group of patients (n = 25) 5 years later (follow-up study). PWV-ratio increased in the ESRD cohort with respect to the control group (1.03 ± 0.23 vs. 1.31 ± 0.37; p hydration status, but not with the blood pressure. PWV-ratio could be considered a blood pressure-independent parameter, associated with the age and hydration status of the patient.

  19. Light storage via slow-light four-wave mixing

    International Nuclear Information System (INIS)

    Fan, Yun-Fei; Wang, Hai-Hua; Wei, Xiao-Gang; Li, Ai-Jun; Kang, Zhi-Hui; Wu, Jin-Hui; Zhang, Han-Zhuang; Xu, Huai-Liang; Gao, Jin-Yue

    2012-01-01

    We experimentally demonstrate a light storage via slow-light four-wave mixing in a solid-state medium with a four-level double lambda scheme. Using slow light based on electromagnetically induced transparency, we obtain a slowed four-wave mixing signal pulse together with the slowed probe pulse. During the propagation of light pulses, the storage and retrieval of both the slowed four-wave mixing pulse and the slowed probe pulse are studied by manipulating the intensities of the control fields. -- Highlights: ► A light storage via slow-light four-wave mixing is observed in a solid. ► The probe pulse is slowed under electromagnetically induced transparency. ► A slowed four-wave mixing pulse is obtained by slow light. ► The storage of slowed double pulses is studied.

  20. Ultrarelativistic electromagnetic pulses in plasmas

    Science.gov (United States)

    Ashour-Abdalla, M.; Leboeuf, J. N.; Tajima, T.; Dawson, J. M.; Kennel, C. F.

    1981-01-01

    The physical processes of a linearly polarized electromagnetic pulse of highly relativistic amplitude in an underdense plasma accelerating particles to very high energies are studied through computer simulation. An electron-positron plasma is considered first. The maximum momenta achieved scale as the square of the wave amplitude. This acceleration stops when the bulk of the wave energy is converted to particle energy. The pulse leaves behind as a wake a vacuum region whose length scales as the amplitude of the wave. The results can be explained in terms of a snow plow or piston-like action of the radiation on the plasma. When a mass ratio other than unity is chosen and electrostatic effects begin to play a role, first the ion energy increases faster than the electron energy and then the electron energy catches up later, eventually reaching the same value.

  1. Sound Beams with Shockwave Pulses

    Science.gov (United States)

    Enflo, B. O.

    2000-11-01

    The beam equation for a sound beam in a diffusive medium, called the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, has a class of solutions, which are power series in the transverse variable with the terms given by a solution of a generalized Burgers’ equation. A free parameter in this generalized Burgers’ equation can be chosen so that the equation describes an N-wave which does not decay. If the beam source has the form of a spherical cap, then a beam with a preserved shock can be prepared. This is done by satisfying an inequality containing the spherical radius, the N-wave pulse duration, the N-wave pulse amplitude, and the sound velocity in the fluid.

  2. PULSE SYNTHESIZING GENERATOR

    Science.gov (United States)

    Kerns, Q.A.

    1963-08-01

    >An electronlc circuit for synthesizing electrical current pulses having very fast rise times includes several sinewave generators tuned to progressively higher harmonic frequencies with signal amplitudes and phases selectable according to the Fourier series of the waveform that is to be synthesized. Phase control is provided by periodically triggering the generators at precisely controlled times. The outputs of the generators are combined in a coaxial transmission line. Any frequency-dependent delays that occur in the transmission line can be readily compensated for so that the desired signal wave shape is obtained at the output of the line. (AEC)

  3. The Pulse Line Ion Accelerator Concept

    Energy Technology Data Exchange (ETDEWEB)

    Briggs, Richard J.

    2006-02-15

    The Pulse Line Ion Accelerator concept was motivated by the desire for an inexpensive way to accelerate intense short pulse heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. A pulse power driver applied at one end of a helical pulse line creates a traveling wave pulse that accelerates and axially confines the heavy ion beam pulse. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/meter acceleration gradients. The concept might be described crudely as an ''air core'' induction linac where the PFN is integrated into the beam line so the accelerating voltage pulse can move along with the ions to get voltage multiplication.

  4. Pulse plating

    CERN Document Server

    Hansal, Wolfgang E G; Green, Todd; Leisner, Peter; Reichenbach, Andreas

    2012-01-01

    The electrodeposition of metals using pulsed current has achieved practical importance in recent years. Although it has long been known that changes in potential, with or without polarity reversal, can significantly affect the deposition process, the practical application of this has been slow to be adopted. This can largely be explained in terms of the complex relationship between the current regime and its effect on the electrodeposition process. In order to harness these effects, an understanding of the anodic and cathodic electrochemical processes is necessary, together with the effects of polarity reversal and the rate of such reversals. In this new monograph, the basics of metal electrodeposition from solution are laid out in great detail in seven distinct chapters. With this knowledge, the reader is able to predict how a given pulse train profile can be adopted to achieve a desired outcome. Equally important is the choice of a suitable rectifier and the ancillary control circuits to enable pulse platin...

  5. Velocidade da onda de pulso, pressão arterial e adipocitocinas em adultos jovens: estudo do Rio de Janeiro Pulse wave velocity, blood pressure and adipocytokines in young adults: the Rio de Janeiro study

    Directory of Open Access Journals (Sweden)

    Oswaldo Luiz Pizzi

    2013-01-01

    identificação do acometimento vascular nessa faixa etária.BACKGROUND: Data on noninvasive vascular assessment and their association with cardiovascular risk variables are scarce in young individuals. OBJECTIVE: To evaluate the association between pulse wave velocity and blood pressure, anthropometric and metabolic variables, including adipocytokines, in young adults. METHODS: A total of 96 individuals aged 26 to 35 years (mean 30.09 ± 1.92; 51 males were assessed in the Rio de Janeiro study. Pulse wave velocity (Complior method, blood pressure, body mass index, glucose, lipid profile, leptin, insulin, adiponectin and insulin resistance index (HOMA-IR were analyzed. Subjects were stratified into three groups according to the PWV tertile for each gender. RESULTS: The group with the highest pulse wave velocity (PWV tertile showed higher mean systolic and diastolic blood pressure, mean blood pressure, body mass index, insulin, and HOMA-IR, as well as lower mean adiponectin; higher prevalence of diabetes mellitus/glucose intolerance and hyperinsulinemia. There was a significant positive correlation of PWV with systolic blood pressure, diastolic blood pressure, pulse pressure and mean blood pressure, body mass index, and LDL-cholesterol, and a negative correlation with HDL-cholesterol and adiponectin. In the multiple regression model, after adjustment of HDL-cholesterol, LDL-cholesterol and adiponectin for gender, age, body mass index and mean blood pressure, only the male gender and mean blood pressure remained significantly correlated with PWV. CONCLUSION: PWV in young adults showed a significant association with cardiovascular risk variables, especially in the male gender, and mean blood pressure as important determinant variables. The findings suggest that PWV measurement can be useful for the identification of vascular impairment in this age group.

  6. Velocidade da onda de pulso, pressão arterial e adipocitocinas em adultos jovens: estudo do Rio de Janeiro Pulse wave velocity, blood pressure and adipocytokines in young adults: the Rio de Janeiro study

    Directory of Open Access Journals (Sweden)

    Oswaldo Luiz Pizzi

    2012-01-01

    identificação do acometimento vascular nessa faixa etária.BACKGROUND: Data on noninvasive vascular assessment and their association with cardiovascular risk variables are scarce in young individuals. OBJECTIVE: To evaluate the association between pulse wave velocity and blood pressure, anthropometric and metabolic variables, including adipocytokines, in young adults. METHODS: A total of 96 individuals aged 26 to 35 years (mean 30.09 ± 1.92; 51 males were assessed in the Rio de Janeiro study. Pulse wave velocity (Complior method, blood pressure, body mass index, glucose, lipid profile, leptin, insulin, adiponectin and insulin resistance index (HOMA-IR were analyzed. Subjects were stratified into three groups according to the PWV tertile for each gender. RESULTS: The group with the highest pulse wave velocity (PWV tertile showed higher mean systolic and diastolic blood pressure, mean blood pressure, body mass index, insulin, and HOMA-IR, as well as lower mean adiponectin; higher prevalence of diabetes mellitus/glucose intolerance and hyperinsulinemia. There was a significant positive correlation of PWV with systolic blood pressure, diastolic blood pressure, pulse pressure and mean blood pressure, body mass index, and LDL-cholesterol, and a negative correlation with HDL-cholesterol and adiponectin. In the multiple regression model, after adjustment of HDL-cholesterol, LDL-cholesterol and adiponectin for gender, age, body mass index and mean blood pressure, only the male gender and mean blood pressure remained significantly correlated with PWV. CONCLUSION: PWV in young adults showed a significant association with cardiovascular risk variables, especially in the male gender, and mean blood pressure as important determinant variables. The findings suggest that PWV measurement can be useful for the identification of vascular impairment in this age group.

  7. Highly Supersonic Ion Pulses in a Collisionless Magnetized Plasma

    DEFF Research Database (Denmark)

    Juul Rasmussen, Jens; Schrittwieser, R.

    1982-01-01

    The initial transient response of a collisionless plasma to a high positive voltage step is investigated. Four different pulses are observed. An electron plasma wave pulse is followed by an ion burst. The latter is overtaken and absorbed by a highly supersonic ion pulse. Thereafter, an ion...

  8. Molecular dynamics study of lubricant depletion by pulsed laser heating

    Science.gov (United States)

    Seo, Young Woo; Rosenkranz, Andreas; Talke, Frank E.

    2018-05-01

    In this study, molecular dynamics simulations were performed to numerically investigate the effect of pulsed laser heating on lubricant depletion. The maximum temperature, the lubricant depletion width, the number of evaporated lubricant beads and the number of fragmented lubricant chains were studied as a function of laser peak power, pulse duration and repetition rate. A continuous-wave laser and a square pulse laser were simulated and compared to a Gaussian pulse laser. With increasing repetition rate, pulsed laser heating was found to approach continuous-wave laser heating.

  9. Faraday tarotion: new parameter for electromagnetic pulse propagation in magnetoplasma

    International Nuclear Information System (INIS)

    Bloch, S.C.; Lyons, P.W.

    1976-01-01

    Extreme distortion and time-dependent Faraday rotation occur for propagation of short electromagnetic pulses in magnetoplasma, for some ranges of plasma parameters. In order to relate pulse and monochromatic waves for propagation-path diagnostic purposes, a new parameter is introduced for the transmitted pulse train which has properties that correspond very accurately to results that would be expected for Faraday rotation of a continuous wave having the central frequency of the incident pulse spectrum. Results for 5-ns pulses (10 GHz) are presented for varying propagating length, static magnetic field, electron density, and collisional absorption

  10. Effect of laser pulse energies in laser induced breakdown spectroscopy in double-pulse configuration

    International Nuclear Information System (INIS)

    Benedetti, P.A.; Cristoforetti, G.; Legnaioli, S.; Palleschi, V.; Pardini, L.; Salvetti, A.; Tognoni, E.

    2005-01-01

    In this paper, the effect of laser pulse energy on double-pulse laser induced breakdown spectroscopy signal is studied. In particular, the energy of the first pulse has been changed, while the second pulse energy is held fixed. A systematic study of the laser induced breakdown spectroscopy signal dependence on the interpulse delay is performed, and the results are compared with the ones obtained with a single laser pulse of energy corresponding to the sum of the two pulses. At the same time, the crater formed at the target surface is studied by video-confocal microscopy, and the variation in crater dimensions is correlated to the enhancement of the laser induced breakdown spectroscopy signal. The results obtained are consistent with the interpretation of the double-pulse laser induced breakdown spectroscopy signal enhancement in terms of the changes in ambient gas pressure produced by the shock wave induced by the first laser pulse

  11. A Study of New Pulse Auscultation System

    Directory of Open Access Journals (Sweden)

    Ying-Yun Chen

    2015-04-01

    Full Text Available This study presents a new type of pulse auscultation system, which uses a condenser microphone to measure pulse sound waves on the wrist, captures the microphone signal for filtering, amplifies the useful signal and outputs it to an oscilloscope in analog form for waveform display and storage and delivers it to a computer to perform a Fast Fourier Transform (FFT and convert the pulse sound waveform into a heartbeat frequency. Furthermore, it also uses an audio signal amplifier to deliver the pulse sound by speaker. The study observed the principles of Traditional Chinese Medicine’s pulsing techniques, where pulse signals at places called “cun”, “guan” and “chi” of the left hand were measured during lifting (100 g, searching (125 g and pressing (150 g actions. Because the system collects the vibration sound caused by the pulse, the sensor itself is not affected by the applied pressure, unlike current pulse piezoelectric sensing instruments, therefore, under any kind of pulsing pressure, it displays pulse changes and waveforms with the same accuracy. We provide an acquired pulse and waveform signal suitable for Chinese Medicine practitioners’ objective pulse diagnosis, thus providing a scientific basis for this Traditional Chinese Medicine practice. This study also presents a novel circuit design using an active filtering method. An operational amplifier with its differential features eliminates the interference from external signals, including the instant high-frequency noise. In addition, the system has the advantages of simple circuitry, cheap cost and high precision.

  12. A study of new pulse auscultation system.

    Science.gov (United States)

    Chen, Ying-Yun; Chang, Rong-Seng

    2015-04-14

    This study presents a new type of pulse auscultation system, which uses a condenser microphone to measure pulse sound waves on the wrist, captures the microphone signal for filtering, amplifies the useful signal and outputs it to an oscilloscope in analog form for waveform display and storage and delivers it to a computer to perform a Fast Fourier Transform (FFT) and convert the pulse sound waveform into a heartbeat frequency. Furthermore, it also uses an audio signal amplifier to deliver the pulse sound by speaker. The study observed the principles of Traditional Chinese Medicine's pulsing techniques, where pulse signals at places called "cun", "guan" and "chi" of the left hand were measured during lifting (100 g), searching (125 g) and pressing (150 g) actions. Because the system collects the vibration sound caused by the pulse, the sensor itself is not affected by the applied pressure, unlike current pulse piezoelectric sensing instruments, therefore, under any kind of pulsing pressure, it displays pulse changes and waveforms with the same accuracy. We provide an acquired pulse and waveform signal suitable for Chinese Medicine practitioners' objective pulse diagnosis, thus providing a scientific basis for this Traditional Chinese Medicine practice. This study also presents a novel circuit design using an active filtering method. An operational amplifier with its differential features eliminates the interference from external signals, including the instant high-frequency noise. In addition, the system has the advantages of simple circuitry, cheap cost and high precision.

  13. Attosecond electron wave packet interferometry

    International Nuclear Information System (INIS)

    Remetter, T.; Ruchon, T.; Johnsson, P.; Varju, K.; Gustafsson, E.

    2006-01-01

    Complete test of publication follows. The well controlled generation and characterization of attosecond XUV light pulses provide an unprecedented tool to study electron wave packets (EWPs). Here a train of attosecond pulses is used to create and study the phase of an EWP in momentum space. There is a clear analogy between electronic wave functions and optical fields. In optics, methods like SPIDER or wave front shearing interferometry, allow to measure the spectral or spatial phase of a light wave. These two methods are based on the same principle: an interferogram is produced when recombining two sheared replica of a light pulse, spectrally (SPIDER) or spatially (wave front shearing interferometry). This enables the comparison of two neighbouring different spectral or spatial slices of the original wave packet. In the experiment, a train of attosecond pulses is focused in an Argon atomic gas jet. EWPs are produced from the single XUV photon ionization of Argon atoms. If an IR beam is synchronized to the EWPs, it is possible to introduce a shear in momentum space between two consecutive s wave packets. A Velocity Map Imaging Spectrometer (VMIS) enables us to detect the interference pattern. An analysis of the interferograms will be presented leading to a conclusion about the symmetry of the studied wave packet.

  14. Cold plasma waves

    International Nuclear Information System (INIS)

    Booker, H.G.

    1984-01-01

    The book aims to present current knowledge concerning the propagation of electromagnetic waves in a homogeneous magnetoplasma for which temperature effects are unimportant. It places roughly equal emphasis on the radio and the hydromagnetic parts of the electromagnetic spectrum. The dispersion properties of a magnetoplasma are treated as a function both of wave frequency (assumed real) and of ionization density. The effect of collisions is included only in so far as this can be done with simplicity. The book describes how pulses are radiated from both small and large antennas embedded in a homogeneous magnetoplasma. The power density radiated from a type of dipole antenna is studied as a function of direction of radiation in all bands of wave frequency. Input reactance is not treated, but the dependence of radiation resistance on wave frequency is described for the entire electromagnetic spectrum. Also described is the relation between beaming and guidance for Alfven waves. (Auth.)

  15. Pulsed power

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The key element of our pulsed power program is concentration of power in time and space by suppression of breakdown in dielectrics and in vacuum. Magnetically insulated vacuum transmission lines and magnetic suppression of insulator flashover have continued as the main reserch directions. Vacuum insulated line studies at Physics International have been expanded and a test bed at Sandia, called MITE (Magnetically Insulated Transmission Experiment), is under development. The choice for the baseline EBFA design will depend on the outcome of these studies and should be made in July 1977. The slow and intermediate speed pulsed power approaches to EBFA will be based on Proto I and Proto II results and several of the projected EBFA subsystems are presently being tested in Proto II. A further stage of power concentration, within the vacuum diode itself, would considerably ease the burden on dielectrics; methods of power multiplication involving magnetically imploded plasmas are being considered and tests have begun using the Ripple III apparatus

  16. Optimal filter bandwidth for pulse oximetry

    Science.gov (United States)

    Stuban, Norbert; Niwayama, Masatsugu

    2012-10-01

    Pulse oximeters contain one or more signal filtering stages between the photodiode and microcontroller. These filters are responsible for removing the noise while retaining the useful frequency components of the signal, thus improving the signal-to-noise ratio. The corner frequencies of these filters affect not only the noise level, but also the shape of the pulse signal. Narrow filter bandwidth effectively suppresses the noise; however, at the same time, it distorts the useful signal components by decreasing the harmonic content. In this paper, we investigated the influence of the filter bandwidth on the accuracy of pulse oximeters. We used a pulse oximeter tester device to produce stable, repetitive pulse waves with digitally adjustable R ratio and heart rate. We built a pulse oximeter and attached it to the tester device. The pulse oximeter digitized the current of its photodiode directly, without any analog signal conditioning. We varied the corner frequency of the low-pass filter in the pulse oximeter in the range of 0.66-15 Hz by software. For the tester device, the R ratio was set to R = 1.00, and the R ratio deviation measured by the pulse oximeter was monitored as a function of the corner frequency of the low-pass filter. The results revealed that lowering the corner frequency of the low-pass filter did not decrease the accuracy of the oxygen level measurements. The lowest possible value of the corner frequency of the low-pass filter is the fundamental frequency of the pulse signal. We concluded that the harmonics of the pulse signal do not contribute to the accuracy of pulse oximetry. The results achieved by the pulse oximeter tester were verified by human experiments, performed on five healthy subjects. The results of the human measurements confirmed that filtering out the harmonics of the pulse signal does not degrade the accuracy of pulse oximetry.

  17. Travelling waves in models of neural tissue: from localised structures to periodic waves

    NARCIS (Netherlands)

    Meijer, Hil Gaétan Ellart; Coombes, Stephen

    2014-01-01

    We consider travelling waves (fronts, pulses and periodics) in spatially extended one dimensional neural field models. We demonstrate for an excitatory field with linear adaptation that, in addition to an expected stable pulse solution, a stable anti-pulse can exist. Varying the adaptation strength

  18. Pulse Wave Velocity and Electroneurophysiological Evaluation in ...

    African Journals Online (AJOL)

    electrophysiological tests for peripheral nervous system involvement. 25 patients (aged between 20-60 years) with rheumatoid arthritis according to the criteria of the American College of Rheumatology and 25 control subjects of the same age and sex were recruited. In the motor conduction studies, out of 25 patients of ...

  19. Prognostic significance of aortic pulse wave velocity

    DEFF Research Database (Denmark)

    Hansen, T.W.; Jeppesen, J.; Torp-Pedersen, Christian Tobias

    2008-01-01

    Om bogen Vascular Hemodynamics This is the only complete work on vascular hemodynamics. Recently, vascular hemodynamics has undergone major advances, resulting from increasingly sophisticated imaging, computational, and clinical research methodologies. The effects of these advances are likely...... to be profound at both the scientific and clinical levels. Now, "Vascular Hemodynamics" provides a self-contained treatment of this rapidly advancing topic as it relates to vascular disease and related pathologies in the human body. Utilizing a multidisciplinary approach encompassing engineering, vascular...

  20. Pulse wave velocity in familial combined hyperlipidemia.

    NARCIS (Netherlands)

    Avest, E. ter; Holewijn, S.; Bredie, S.J.H.; Tits, L.J.H. van; Stalenhoef, A.F.H.; Graaf, J. de

    2007-01-01

    BACKGROUND: In the present cross-sectional study we investigated whether familial combined hyperlipidemia (FCH) is associated with an increased arterial wall stiffness, and whether measures of arterial wall stiffness in FCH family members could contribute to cardiovascular risk stratification.

  1. Experiments on second-sound shock waves in superfluid helium

    International Nuclear Information System (INIS)

    Cummings, J.C.; Schmidt, D.W.; Wagner, W.J.

    1978-01-01

    The waveform and velocity of second-sound waves in superfluid helium have been studied experimentally using superconducting, thin-film probes. The second-sound waves were generated with electrical pulses through a resistive film. Variations in pulse power, pulse duration, and bath temperature were examined. As predicted theoretically, the formation of a shock was observed at the leading or trailing edge of the waves depending on bath temperature. Breakdown of the theoretical model was observed for large pulse powers. Accurate data for the acoustic second-sound speed were derived from the measurements of shock-wave velocities and are compared with previous results

  2. Effects of pulsed electrical field processing on microbial survival, quality change and nutritional characteristics of blueberries

    Science.gov (United States)

    Whole fresh blueberries were treated using a parallel pulsed electric field (PEF) treatment chamber and a sanitizer solution (60 ppm peracetic acid [PAA]) as PEF treatment medium with square wave bipolar pulses at 2 kV/cm electric field strength, 1us pulse width, and 100 pulses per second for 2, 4, ...

  3. Stress wave focusing transducers

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S.R., LLNL

    1998-05-15

    Conversion of laser radiation to mechanical energy is the fundamental process behind many medical laser procedures, particularly those involving tissue destruction and removal. Stress waves can be generated with laser radiation in several ways: creation of a plasma and subsequent launch of a shock wave, thermoelastic expansion of the target tissue, vapor bubble collapse, and ablation recoil. Thermoelastic generation of stress waves generally requires short laser pulse durations and high energy density. Thermoelastic stress waves can be formed when the laser pulse duration is shorter than the acoustic transit time of the material: {tau}{sub c} = d/c{sub s} where d = absorption depth or spot diameter, whichever is smaller, and c{sub s} = sound speed in the material. The stress wave due to thermoelastic expansion travels at the sound speed (approximately 1500 m/s in tissue) and leaves the site of irradiation well before subsequent thermal events can be initiated. These stress waves, often evolving into shock waves, can be used to disrupt tissue. Shock waves are used in ophthalmology to perform intraocular microsurgery and photodisruptive procedures as well as in lithotripsy to fragment stones. We have explored a variety of transducers that can efficiently convert optical to mechanical energy. One such class of transducers allows a shock wave to be focused within a material such that the stress magnitude can be greatly increased compared to conventional geometries. Some transducer tips could be made to operate regardless of the absorption properties of the ambient media. The size and nature of the devices enable easy delivery, potentially minimally-invasive procedures, and precise tissue- targeting while limiting thermal loading. The transducer tips may have applications in lithotripsy, ophthalmology, drug delivery, and cardiology.

  4. PULSE COLUMN

    Science.gov (United States)

    Grimmett, E.S.

    1964-01-01

    This patent covers a continuous countercurrent liquidsolids contactor column having a number of contactor states each comprising a perforated plate, a layer of balls, and a downcomer tube; a liquid-pulsing piston; and a solids discharger formed of a conical section at the bottom of the column, and a tubular extension on the lowest downcomer terminating in the conical section. Between the conical section and the downcomer extension is formed a small annular opening, through which solids fall coming through the perforated plate of the lowest contactor stage. This annular opening is small enough that the pressure drop thereacross is greater than the pressure drop upward through the lowest contactor stage. (AEC)

  5. Pulse radiolysis

    International Nuclear Information System (INIS)

    Greenshields, H.; Seddon, W.A.

    1982-03-01

    This supplement to two bibliographies published in 1970 and 1972 lists 734 references to the literature of pulse radiolysis, arranged under eight broad subject headings. The references were compiled by searching Biological Abstracts, Chemical Abstracts, Nuclear Science Abstracts and the Weekly List of Papers in Radiation Chemistry issued by the Radiation Chemistry Data Center of Notre Dame University. Full bibliographic data is given for papers published in the period 1971 to 1974. A personal author index listing more than 600 authors and a similar number of co-authors is included

  6. Pulse pile-up. I: Short pulses

    International Nuclear Information System (INIS)

    Wilkinson, D.H.

    1990-07-01

    The search for rare large pulses against an intense background of smaller ones involves consideration of pulse pile-up. Approximate methods are presented, based on ruin theory, by which the probability of such pile-up may be estimated for pulses of arbitrary form and of arbitrary pulse-height distribution. These methods are checked against cases for which exact solutions are available. The present paper is concerned chiefly with short pulses of finite total duration. (Author) (5 refs., 24 figs.)

  7. Modulational instability of coupled waves

    International Nuclear Information System (INIS)

    McKinstrie, C.J.; Bingham, R.

    1989-01-01

    The collinear propagation of an arbitrary number of finite-amplitude waves is modeled by a system of coupled nonlinear Schroedinger equations; one equation for each complex wave amplitude. In general, the waves are modulationally unstable with a maximal growth rate larger than the modulational growth rate of any wave alone. Moreover, waves that are modulationally stable by themselves can be driven unstable by the nonlinear coupling. The general theory is then applied to the relativistic modulational instability of two laser beams in a beat-wave accelerator. For parameters typical of a proposed beat-wave accelerator, this instability can seriously distort the incident laser pulse shapes on the particle-acceleration time scale, with detrimental consequences for particle acceleration

  8. Guided acoustic wave inspection system

    Science.gov (United States)

    Chinn, Diane J.

    2004-10-05

    A system for inspecting a conduit for undesirable characteristics. A transducer system induces guided acoustic waves onto said conduit. The transducer system detects the undesirable characteristics of the conduit by receiving guided acoustic waves that contain information about the undesirable characteristics. The conduit has at least two sides and the transducer system utilizes flexural modes of propagation to provide inspection using access from only the one side of the conduit. Cracking is detected with pulse-echo testing using one transducer to both send and receive the guided acoustic waves. Thinning is detected in through-transmission testing where one transducer sends and another transducer receives the guided acoustic waves.

  9. Chirped pulse digital holography for measuring the sequence of ultrafast optical wavefronts

    Science.gov (United States)

    Karasawa, Naoki

    2018-04-01

    Optical setups for measuring the sequence of ultrafast optical wavefronts using a chirped pulse as a reference wave in digital holography are proposed and analyzed. In this method, multiple ultrafast object pulses are used to probe the temporal evolution of ultrafast phenomena and they are interfered with a chirped reference wave to record a digital hologram. Wavefronts at different times can be reconstructed separately from the recorded hologram when the reference pulse can be treated as a quasi-monochromatic wave during the pulse width of each object pulse. The feasibility of this method is demonstrated by numerical simulation.

  10. Prospective Study of Arterial Stiffness and Subsequent Cognitive Decline Among Community-Dwelling Older Japanese

    Directory of Open Access Journals (Sweden)

    Yu Taniguchi

    2015-09-01

    Full Text Available Background: Brachial-ankle pulse wave velocity (baPWV is inversely associated with cognitive function. However, it is not known whether baPWV predicts cognitive decline (CD in later life. We examined whether or not baPWV is an independent risk marker of subsequent CD in a population of older Japanese. Methods: Among 982 adults aged 65 years or older who participated in a baseline survey, 526 cognitively intact adults (Mini-Mental State Examination [MMSE] score ≥24; mean [SD] age, 71.7 [5.6] years; women, 57.8% were followed for a period of up to 5 years. Pulse wave velocity was determined using an automated waveform analyser. Cognition was assessed by the MMSE, and CD was defined as a decrease of two points or more on the MMSE. Results: During an average follow-up of 3.4 years, 85 participants (16.2% developed CD. After controlling for important confounders, the odds ratios for CD in the highest and middle tertiles of baPWV, as compared with the lowest tertile, were 2.95 (95% confidence interval, 1.29–6.74 and 2.39 (95% confidence interval, 1.11–5.15, respectively. Conclusions: High baPWV was an independent predictor of CD in a general population of older adults and may be useful in the clinical evaluation of elders.

  11. Nondispersive Wave Packets.

    Science.gov (United States)

    Shaarawi, Amr Mohamed

    In this work, nondispersive wavepacket solutions to linear partial differential equations are investigated. These solutions are characterized by infinite energy content; otherwise they are continuous, nonsingular and propagate in free space without spreading out. Examples of such solutions are Berry and Balazs' Airy packet, MacKinnon's wave packet and Brittingham's Focus Wave Mode (FWM). It is demonstrated in this thesis that the infinite energy content is not a basic problem per se and that it can be dealt with in two distinct ways. First these wave packets can be used as bases to construct highly localized, slowly decaying, time-limited pulsed solutions. In the case of the FWMs, this path leads to the formulation of the bidirectional representation, a technique that provides the most natural basis for synthesizing Brittingham-like solutions. This representation is used to derive new exact solutions to the 3-D scalar wave equation. It is also applied to problems involving boundaries, in particular to the propagation of a localized pulse in a infinite acoustic waveguide and to the launchability of such a pulse from the opening of a semi-infinite waveguide. The second approach in dealing with the infinite energy content utilizes the bump-like structure of nondispersive solutions. With an appropriate choice of parameters, these bump fields have very large amplitudes around the centers, in comparison to their tails. In particular, the FWM solutions are used to model massless particles and are capable of providing an interesting interpretation to the results of Young's two slit experiment and to the wave-particle duality of light. The bidirectional representation provides, also, a systematic way of deriving packet solutions to the Klein-Gordon, the Schrodinger and the Dirac equations. Nondispersive solutions of the former two equations are compared to previously derived ones, e.g., the Airy packet and MacKinnon's wave packet.

  12. High frequency and pulse scattering physical acoustics

    CERN Document Server

    Pierce, Allan D

    1992-01-01

    High Frequency and Pulse Scattering investigates high frequency and pulse scattering, with emphasis on the phenomenon of echoes from objects. Geometrical and catastrophe optics methods in scattering are discussed, along with the scattering of sound pulses and the ringing of target resonances. Caustics and associated diffraction catastrophes are also examined.Comprised of two chapters, this volume begins with a detailed account of geometrically based approximation methods in scattering theory, focusing on waves transmitted through fluid and elastic scatterers and glory scattering; surface ray r

  13. Statistical analysis of random pulse trains

    International Nuclear Information System (INIS)

    Da Costa, G.

    1977-02-01

    Some experimental and theoretical results concerning the statistical properties of optical beams formed by a finite number of independent pulses are presented. The considered waves (corresponding to each pulse) present important spatial variations of the illumination distribution in a cross-section of the beam, due to the time-varying random refractive index distribution in the active medium. Some examples of this kind of emission are: (a) Free-running ruby laser emission; (b) Mode-locked pulse trains; (c) Randomly excited nonlinear media

  14. Evidence of localized wave transmission

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    LLNL [Lawrence Livermore National Lab.] experiments to test the feasibility of launching an acoustic, directed-energy pulse train (ADEPT) in water have demonstrated localized transmission of wave energy far beyond the classical Rayleigh length that defines the boundary between near-field and far-field transmission for Gaussian (diffraction-limited) pulses. The results of the experiments are in excellent agreement with computer simulations

  15. Electromagnetic wave collapse in a radiation background

    International Nuclear Information System (INIS)

    Marklund, Mattias; Brodin, Gert; Stenflo, Lennart

    2003-01-01

    The nonlinear interaction, due to quantum electrodynamical (QED) effects between an electromagnetic pulse and a radiation background, is investigated by combining the methods of radiation hydrodynamics with the QED theory for photon-photon scattering. For the case of a single coherent electromagnetic pulse, we obtain a Zakharov-like system, where the radiation pressure of the pulse acts as a driver of acoustic waves in the photon gas. For a sufficiently intense pulse and/or background energy density, there is focusing and the subsequent collapse of the pulse. The relevance of our results for various astrophysical applications are discussed

  16. Shock wave physics group (M-6)

    International Nuclear Information System (INIS)

    Morris, C.E.

    1981-01-01

    Experimental facilities and activities of the shock wave physics group at LASL are described. The facilities include a compressed gas gun, two-stage gas gun, high explosive facilities, and a pulsed megagauss field facility

  17. Optical surgical navigation system causes pulse oximeter malfunction.

    Science.gov (United States)

    Satoh, Masaaki; Hara, Tetsuhito; Tamai, Kenji; Shiba, Juntaro; Hotta, Kunihisa; Takeuchi, Mamoru; Watanabe, Eiju

    2015-01-01

    An optical surgical navigation system is used as a navigator to facilitate surgical approaches, and pulse oximeters provide valuable information for anesthetic management. However, saw-tooth waves on the monitor of a pulse oximeter and the inability of the pulse oximeter to accurately record the saturation of a percutaneous artery were observed when a surgeon started an optical navigation system. The current case is thought to be the first report of this navigation system interfering with pulse oximetry. The causes of pulse jamming and how to manage an optical navigation system are discussed.

  18. Radiation and propagation of short acoustical pulses from underground explosions

    International Nuclear Information System (INIS)

    Banister, J.R.

    1982-06-01

    Radiation and propagation of short acoustical pulses from underground nuclear explosions were analyzed. The cone of more intense radiation is defined by the ratio of sound speeds in the ground and air. The pressure history of the radiated pulse is a function of the vertical ground-motion history, the range, the burial depth, and the velocity of longitudinal seismic waves. The analysis of short-pulse propagation employed an N-wave model with and without enegy conservation. Short pulses with initial wave lengths less than 100 m are severely attenuated by the energy loss in shocks and viscous losses in the wave interior. The methods developed in this study should be useful for system analysis

  19. Gravitational waves and dragging effects

    Science.gov (United States)

    Bičák, Jiří; Katz, Joseph; Lynden-Bell, Donald

    2008-08-01

    Linear and rotational dragging effects of gravitational waves on local inertial frames are studied in purely vacuum spacetimes. First, the linear dragging caused by a simple cylindrical pulse is investigated. Surprisingly strong transverse effects of the pulse are exhibited. The angular momentum in cylindrically symmetric spacetimes is then defined and confronted with some results in the literature. In the main part, a general procedure is developed for studying weak gravitational waves with translational but not axial symmetry which can carry angular momentum. After a suitable averaging the rotation of local inertial frames due to such rotating waves can be calculated explicitly and illustrated graphically. This is done in detail in the accompanying paper. Finally, the rotational dragging is given for strong cylindrical waves interacting with a rotating cosmic string with a small angular momentum.

  20. Controlling the spreading of wave packets of a dissociating molecule

    DEFF Research Database (Denmark)

    Tiwari, Ashwani Kumar; Møller, Klaus Braagaard; Henriksen, Niels Engholm

    2007-01-01

    A first-order perturbation theoretic approach within the electric-dipole approximation is used to study the time evolution of wave packets created by linearly chirped laser pulses on a repulsive potential of Br-2. Our calculations show that negatively chirped pulses focus the wave packet in the F...

  1. Electromagnetic pulses in a strongly magnetized electron-positron plasma

    International Nuclear Information System (INIS)

    Yu, M.Y.; Rao, N.N.

    1985-01-01

    The conditions for the existence of large-amplitude localized electromagnetic wave pulses in an electron-positron plasma penetrated by a very strong ambient magnetic field are obtained. It is shown that such pulses can exist in pulsar polar magnetospheres. 12 references

  2. Interaction of solitary pulses in single mode optical fibres | Usman ...

    African Journals Online (AJOL)

    Two solitary waves launched, by way of incidence, into an optical fibre from a single pulse if the pulses are in-phase as understood from results of inverse scattering transform method applied to the cubic nonlinear Schrödinger equations, (CNLSE\\'s). The single CNLSE is then understood to describe evolution of coupled ...

  3. Generation of ultrafast pulse via combined effects of stimulated

    Indian Academy of Sciences (India)

    A project of ultrafast pulse generation has been presented and demonstrated by utilizing the combined nonlinear effects of stimulated Raman scattering (SRS) and non-degenerate two-photon absorption (TPA) based on silicon nanophotonic chip, in which a continuous wave (CW) and an ultrafast dark pulse are ...

  4. Nonlinear shaping of a two-dimensional ultrashort ionizing pulse

    International Nuclear Information System (INIS)

    Sergeev, A.; Vanin, E.; Stenflo, L.; Anderson, D.; Lisak, M.; Quiroga-Teixeiro, M.L.

    1992-01-01

    A theoretical description of ultrashort ionizing wave pulses is presented by means of two different models where the ionization rate increases or decreases, respectively, as a function of the electric field amplitude. We show that the pulse evolves either into a horse-shoe or a horn-type structure in the time-space domain. In some parameter regions the intensity of the pulse can also increase. (au)

  5. Tightly localized stationary pulses in a multilevel atomic system

    International Nuclear Information System (INIS)

    Liu, Xiong-Jun; Oh, C. H.; Liu, Xin; Liu, Zheng-Xin; Kwek, L. C.

    2007-01-01

    We show that the pulse matching phenomenon can be obtained in the general multilevel system with electromagnetically induced transparency. For this we find a different way to create tightly localized stationary pulses by using counterpropagating pump fields. The present process is a spatial compression of excitation so that it allows us to shape and further intensify the localized stationary pulses, without using standing waves of pump fields or spatially modulated pump fields

  6. Ionization by a pulsed plasma surface water

    International Nuclear Information System (INIS)

    Bloyet, E.; Leprince, P.; Marec, J.; Llamas Blasco, M.

    1981-01-01

    The ionization mechanism is studied of a pulsed surface wave generating a microwave discharge. When the plasma is dominated by collisions, it is found that the velocity of the ionization front depends on the ponderomotive force due to the field gradient in the front. (orig.)

  7. Coherent pulse position modulation quantum cipher

    Energy Technology Data Exchange (ETDEWEB)

    Sohma, Masaki; Hirota, Osamu [Quantum ICT Research Institute, Tamagawa University, 6-1-1 Tamagawa-gakuen, Machida, Tokyo 194-8610 (Japan)

    2014-12-04

    On the basis of fundamental idea of Yuen, we present a new type of quantum random cipher, where pulse position modulated signals are encrypted in the picture of quantum Gaussian wave form. We discuss the security of our proposed system with a phase mask encryption.

  8. Combine material against electromagnetic pulse disturbance

    International Nuclear Information System (INIS)

    Liu Yan

    2004-01-01

    A novel combined material is introduced, which is hard against electromagnetic pulse disturbance, The attenuation characteristics and the penetration probability of the combine material is discussed in detail. The penetration probability of electromagnetic wave is calculated approximately and the characteristic curve is measured for this material. (authors)

  9. Overview of The Pulse Line Ion Accelerator

    International Nuclear Information System (INIS)

    Briggs, R.J.; Bieniosek, F.M.; Coleman, J.E.; Eylon, S.; Henestroza, E.; Leitner, M.; Logan, B.G.; Reginato, L.L.; Roy, P.K.; Seidl, P.A.; Waldron, W.L.; Yu, S.S.; Barnard, J.J.; Caporaso, G.J.; Friedman, A.; Grote, D.P.; Nelson, S.D.

    2006-01-01

    An overview of the Pulse Line Ion Accelerator (PLIA) concept and its development is presented. In the PLIA concept a pulse power driver applied to one end of a helical pulse line creates a traveling wave pulse that accelerates and axially confines a heavy ion beam pulse The motivation for its development at the IFE-VNL is the acceleration of intense, short pulse, heavy ion beams to regimes of interest for studies of High Energy Density Physics and Warm Dense Matter. Acceleration scenarios with constant parameter helical lines are described which result in output energies of a single stage much larger than the several hundred kilovolt peak voltages on the line, with a goal of 3-5 MeV/meter acceleration gradients. The main attraction of the concept is the very low cost it promises. It might be described crudely as an ''air core'' induction linac where the pulse-forming network is integrated into the beam line so the accelerating voltage pulse can move along with the ions to get voltage multiplication

  10. Nonlinear surface Alfven waves

    International Nuclear Information System (INIS)

    Cramer, N.F.

    1991-01-01

    The problem of nonlinear surface Alfven waves propagating on an interface between a plasma and a vacuum is discussed, with dispersion provided by the finite-frequency effect, i.e. the finite ratio of the frequency to the ion-cyclotron frequency. A set of simplified nonlinear wave equations is derived using the method of stretched co-ordinates, and another approach uses the generation of a second-harmonic wave and its interaction with the first harmonic to obtain a nonlinear dispersion relation. A nonlinear Schroedinger equation is then derived, and soliton solutions found that propagate as solitary pulses in directions close to parallel and antiparallel to the background magnetic field. (author)

  11. Risks of rapid decline renal function in patients with type 2 diabetes

    Institute of Scientific and Technical Information of China (English)

    Yi-Jing; Sheen; Wayne; HH; Sheu

    2014-01-01

    Progressive rising population of diabetes and related nephropathy, namely, diabetic kidney disease and associated end stage renal disease has become a major global public health issue. Results of observational studies indicate that most diabetic kidney disease progresses over decades; however, certain diabetes patients display a rapid decline in renal function, which may lead to renal failure within months. Although the definition of rapid renal function decline remained speculative, in general,it is defined by the decrease of estimated glomerular filtration rate(e GFR) in absolute rate of loss or percent change. Based on the Kidney Disease: Improving Global Outcomes 2012 clinical practice guidelines, a rapid decline in renal function is defined as a sustained declinein e GFR of > 5 m L/min per 1.73 m2 per year. It has been reported that potential factors contributing to a rapid decline in renal function include ethnic/genetic and demographic causes, smoking habits, increased glycated hemoglobin levels, obesity, albuminuria, anemia, low serum magnesium levels, high serum phosphate levels, vitamin D deficiency, elevated systolic blood pressure, pulse pressure, brachial-ankle pulse wave velocity values, retinopathy, and cardiac autonomic neuropathy. This article reviews current literatures in this area and provides insight on the early detection of diabetic subjects who are at risk of a rapid decline in renal function in order to develop a more aggressive approach to renal and cardiovascular protection.

  12. Acoustic emission linear pulse holography

    International Nuclear Information System (INIS)

    Collins, H.D.; Busse, L.J.; Lemon, D.K.

    1983-01-01

    This paper describes the emission linear pulse holography which produces a chronological linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. A thirty two point sampling array is used to construct phase-only linear holograms of simulated acoustic emission sources on large metal plates. The concept behind the AE linear pulse holography is illustrated, and a block diagram of a data acquisition system to implement the concept is given. Array element spacing, synthetic frequency criteria, and lateral depth resolution are specified. A reference timing transducer positioned between the array and the inspection zone and which inititates the time-of-flight measurements is described. The results graphically illustrate the technique using a one-dimensional FFT computer algorithm (ie. linear backward wave) for an AE image reconstruction

  13. Random pulse generator

    International Nuclear Information System (INIS)

    Guo Ya'nan; Jin Dapeng; Zhao Dixin; Liu Zhen'an; Qiao Qiao; Chinese Academy of Sciences, Beijing

    2007-01-01

    Due to the randomness of radioactive decay and nuclear reaction, the signals from detectors are random in time. But normal pulse generator generates periodical pulses. To measure the performances of nuclear electronic devices under random inputs, a random generator is necessary. Types of random pulse generator are reviewed, 2 digital random pulse generators are introduced. (authors)

  14. Programmable pulse generator

    International Nuclear Information System (INIS)

    Xue Zhihua; Lou Binqiao; Duan Xiaohui

    2002-01-01

    The author introduces the design of programmable pulse generator that is based on a micro-controller and controlled by RS232 interface of personal computer. The whole system has good stability. The pulse generator can produce TTL pulse and analog pulse. The pulse frequency can be selected by EPLD. The voltage amplitude and pulse width of analog pulse can be adjusted by analog switches and digitally-controlled potentiometers. The software development tools of computer is National Instruments LabView5.1. The front panel of this virtual instrumentation is intuitive and easy-to-use. Parameters can be selected and changed conveniently by knob and slide

  15. Steering population transfer of the Na2 molecule by an ultrashort pulse train

    Science.gov (United States)

    Niu, Dong-Hua; Wang, Shuo; Zhan, Wei-Shen; Tao, Hong-Cai; Wang, Si-Qi

    2018-05-01

    We theoretically investigate the complete population transfer among quantum states of the Na2 molecule using ultrashort pulse trains using the time-dependent wave packet method. The population accumulation of the target state can be steered by controlling the laser parameters, such as the variable pulse pairs, the different pulse widths, the time delays and the repetition period between two contiguous pulses; in particular, the pulse pairs and the pulse widths have a great effect on the population transfer. The calculations show that the ultrashort pulse train is a feasible solution, which can steer the population transfer from the initial state to the target state efficiently with lower peak intensities.

  16. Large amplitude solitary waves in a multicomponent plasma with negative ions

    International Nuclear Information System (INIS)

    Nakamura, Y.; Tsukabayashi, I.; Ludwig, G.O.; Ferreira, J.L.

    1987-09-01

    When the concentration of negative ions is larger than a critical value, a small compressive pulse evolves into a subsonic wave train and a large pulse develops into a solitary wave. The threshold amplitude and velocity of the solitary waves are measured and compared with predictions using the pseudopotential method. (author) [pt

  17. Reproducibility of pulse-wave analysis and pulse-wave velocity determination in chronic kidney disease

    DEFF Research Database (Denmark)

    Frimodt-Møller, Marie; Nielsen, Arne Høj; Kamper, Anne-Lise

    2008-01-01

    are highly reproducible in pre-dialysis patients with CKD with the day-to-day variation being in accordance with the intra- and inter-observer variation. Thus, applanation tonometry using the SphygmoCor system is a simple, non-invasive method to assess central haemodynamics in clinical trials in patients......BACKGROUND: Indices of central arterial stiffness, derived by use of applanation tonometry, have shown to be strong independent predictors of cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD). The objective of this study was to evaluate the intra- and inter...... performed under standardized conditions in 19 CKD patients with a mean GFR 25.3 ml/min/1.73 m(2) (range 9.9-42.2) by two trained observers and repeated by one of the observers within a week. RESULTS: The mean inter-observer and day-to-day differences (+/-2 SD) for the augmentation index (AIx) were 0...

  18. Pulsed water jet generated by pulse multiplication

    Czech Academy of Sciences Publication Activity Database

    Dvorský, R.; Sitek, Libor; Sochor, T.

    2016-01-01

    Roč. 23, č. 4 (2016), s. 959-967 ISSN 1330-3651 R&D Projects: GA MŠk(CZ) LO1406; GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : high- pressure pulses * pulse intensifier * pulsed water jet * water hammer effect Subject RIV: JQ - Machines ; Tools Impact factor: 0.723, year: 2016 http://hrcak.srce.hr/163752?lang=en

  19. Few-cycle isolated attosecond pulses

    International Nuclear Information System (INIS)

    Sansone, G.; Benedetti, E.; Calegari, F.; Stagira, S.; Vozzi, C.; Silvestri De, S.; Nisoli, M.

    2006-01-01

    Complete test of publication follows. In the last few years the field of attosecond science has shown impressive and rapid progress, mainly due to the introduction of novel experimental methods for the characterization of extreme ultraviolet (XUV) pulses and attosecond electron wave packets. This development has been also triggered by significant improvements in the control of the electric field of the driving infrared pulses. Particularly interesting for the applications is the generation of isolated attosecond XUV pulses using few-cycle driving pulses. In this case significant progresses have been achieved thanks to the stabilization of the carrier-envelope phase (CEP) of amplified light pulses. In this work we demonstrate that the polarization gating (PG) method with few-cycle phase-stabilized driving pulses allows one to generate few-cycle isolated attosecond pulses tunable on a very broad spectral region. The PG method is based on temporal modulation of the ellipticity of a light pulse, which confines the XUV emission in the temporal gate where the polarization is close to linear. The time-dependent polarization of phase-stabilized sub-6-fs pulses, generated by the hollow fiber technique, has been obtained using two birefringent plates. It is possible to create a linear polarization gate, whose position is imposed by the intensity profile of the pulse whilst the emission time is linked to the CEP of the electric field. The pulses have been analyzed by using a flat-field spectrometer. Continuous XUV spectra, corresponding to the production of isolated attosecond pulses, have been generated for particular CEP values. Upon changing the rotation of the first plate it was possible to tune the XUV emission in a broad spectra range. We have then achieved a complete temporal characterization of the generated isolated attosecond pulses using frequency-resolved optical gating for complete reconstruction of attosecond bursts (FROG CRAB). The measured parabolic phase

  20. Effects of safflower seed extract on arterial stiffness

    Directory of Open Access Journals (Sweden)

    Katsuya Suzuki

    2010-11-01

    Full Text Available Katsuya Suzuki1, Shigekazu Tsubaki2, Masami Fujita3, Naoto Koyama1, Michio Takahashi1, Kenji Takazawa41Research Institute for Health Fundamentals, Ajinomoto Co., Inc., Kawasaki; 2Samoncho Clinic, Tokyo; 3Shinanozaka Clinic, Tokyo; 4Tokyo Medical University Hachioji Medical Center, Tokyo, JapanAbstract: Safflower seed extract (SSE contains characteristic polyphenols and serotonin derivatives (N-(p-coumaroyl serotonin and N-feruloylserotonin, which are reported to inhibit oxidation of low-density lipoprotein (LDL, formation of atherosclerotic plaques, and improve arterial stiffness as assessed by pulse wave analysis in animal models. The effects of long-term supplementation with SSE on arterial stiffness in human subjects were evaluated. This double-blind, placebo-controlled study was conducted in 77 males (35–65 years and 15 postmenopausal females (55–65 years with high-normal blood pressure or mild hypertension who were not undergoing treatment. Subjects received SSE (70 mg/day as serotonin derivatives or placebo for 12 weeks, and pulse wave measurements, ie, second derivative of photoplethysmogram (SDPTG, augmentation index, and brachial-ankle pulse wave velocity (baPWV were conducted at baseline, and at weeks 4, 8, and 12. Vascular age estimated by SDPTG aging index improved in the SSE-supplemented group when compared with the placebo group at four (P = 0.0368 and 12 weeks (P = 0.0927. The trend of augmentation index reduction (P = 0.072 versus baseline was observed in the SSE-supplemented group, but reduction of baPWV by SSE supplementation was not observed. The SSE-supplemented group also showed a trend towards a lower malondialdehyde-modified-LDL autoantibody titer at 12 weeks from baseline. These results suggest long-term ingestion of SSE in humans could help to improve arterial stiffness.Keywords: safflower, serotonin derivatives, antioxidants, augmentation index, pulse wave velocity

  1. Plasma waves

    CERN Document Server

    Swanson, DG

    1989-01-01

    Plasma Waves discusses the basic development and equations for the many aspects of plasma waves. The book is organized into two major parts, examining both linear and nonlinear plasma waves in the eight chapters it encompasses. After briefly discussing the properties and applications of plasma wave, the book goes on examining the wave types in a cold, magnetized plasma and the general forms of the dispersion relation that characterize the waves and label the various types of solutions. Chapters 3 and 4 analyze the acoustic phenomena through the fluid model of plasma and the kinetic effects. Th

  2. Influence of ion bombardment on structural and electrical properties of SiO2 thin films deposited from O2/HMDSO inductively coupled plasmas under continuous wave and pulsed modes

    International Nuclear Information System (INIS)

    Bousquet, A.; Goullet, A.; Leteinturier, C.; Granier, A.; Coulon, N.

    2008-01-01

    Low pressure Plasma Enhanced Chemical Vapour Deposition is commonly used to deposit insulators on temperature sensitive substrates. In these processes, the ion bombardment experienced by films during its growth is known to have benefits but also some disadvantages on material properties. In the present paper, we investigate the influence of this bombardment on the structure and the electrical properties of SiO 2 -like film deposited from oxygen/hexa-methyl-di-siloxane radiofrequency plasma in continuous and pulsed modes. First, we studied the ion kinetics thanks to time-resolved measurements by Langmuir probe. After, we showed the ion bombardment in such plasma controls the OH bond content in deposited films. Finally, we highlight the impressive reduction of fixed charge and interface state densities in films obtained in pulsed mode due to a lower ion bombardment. (authors)

  3. Laser pulse stacking method

    Science.gov (United States)

    Moses, E.I.

    1992-12-01

    A laser pulse stacking method is disclosed. A problem with the prior art has been the generation of a series of laser beam pulses where the outer and inner regions of the beams are generated so as to form radially non-synchronous pulses. Such pulses thus have a non-uniform cross-sectional area with respect to the outer and inner edges of the pulses. The present invention provides a solution by combining the temporally non-uniform pulses in a stacking effect to thus provide a more uniform temporal synchronism over the beam diameter. 2 figs.

  4. Terahertz pulse generation from metal nanoparticle ink

    Science.gov (United States)

    Kato, Kosaku; Takano, Keisuke; Tadokoro, Yuzuru; Phan, Thanh Nhat Khoa; Nakajima, Makoto

    2016-11-01

    Terahertz pulse generation from metallic nanostructures irradiated by femtosecond laser pulses is of interest because the conversion efficiency from laser pulses to terahertz waves is increased by the local field enhancement resulting from the plasmon oscillation. In this talk we present our recent study on terahertz generation from metal nanoparticle ink. We baked a silver nanoparticle ink spin-coated onto a glass coverslip in various temperatures. On the surface of the baked ink, bumpy nanostructures are spontaneously formed, and the average size of bumps depends on the baking temperature. These structures are expected to lead to local field enhancement and then large nonlinear polarizations on the surface. The baked ink was irradiated by the output of regeneratively amplified Ti:sapphire femtosecond laser at an incidence angle of 45°. Waveforms of generated terahertz pulses are detected by electro-optical sampling. The generation efficiency was high when the average diameter of bumps was around 100 nm, which is realized when the ink is baked in 205 to 235°C in our setup. One of our next research targets is terahertz wave generation from micro-patterned metallic nanoparticle ink. It is an advantage of the metal nanoparticle ink that by using inkjet printers one can fabricate various patterns with micrometer scales, in which terahertz waves have a resonance. Combination of microstructures made by a printer and nanostructure spontaneously formed in the baking process will provide us terahertz emitters with unique frequency characteristics.

  5. Detection of the Typical Pulse Condition on Cun-Guan-Chi Based on Image Sensor

    Directory of Open Access Journals (Sweden)

    Aihua ZHANG

    2014-02-01

    Full Text Available In order to simulate the diagnosis by feeling the pulse with Traditional Chinese Medicine, a device based on CCD was designed to detect the pulse image of Cun-Guan-Chi. Using the MM-3 pulse model as experimental subject, the synchronous pulse image data of some typical pulse condition were collected by this device on Cun-Guan-Chi. The typical pulses include the normal pulse, the slippery pulse, the slow pulse and the soft pulse. According to the lens imaging principle, the pulse waves were extracted by using the area method, then the 3D pulse condition image was restructured and some features were extracted including the period, the frequency, the width, and the length. The slippery pulse data of pregnant women were collected by this device, and the pulse images were analyzed. The results are consistent based on comparing the features of the slippery pulse model with the slippery pulse of pregnant women. This study overcame shortages of the existing detection device such as the few detecting parts and the limited information, and more comprehensive 3D pulse condition information could be obtained. This work laid a foundation for realizing the objective diagnosis and revealing the comprehensive information of the pulse.

  6. Potential and limitations of wave intensity analysis in coronary arteries

    NARCIS (Netherlands)

    Siebes, M.; Kolyva, C.; Verhoeff, B.J.; Piek, J.J.; Spaan, J.A.

    2009-01-01

    Wave intensity analysis (WIA) is beginning to be applied to the coronary circulation both to better understand coronary physiology and as a diagnostic tool. Separation of wave intensity (WI) into forward and backward traveling components requires knowledge of pulse wave velocity at the point of

  7. Experimental study and modelisation of a pulse tube refrigerator

    International Nuclear Information System (INIS)

    Ravex, A.; Rolland, P.; Liang, J.

    1992-01-01

    A test bench for pulse tube refrigerator characterization has been built. In various configurations (basic pulse tube, orifice pulse tube and double inlet pulse tube), the ultimate temperature and the cooling power have been measured as a function of pressure wave amplitude and frequency for various geometries. A lowest temperature of 28 K has been achieved in a single staged double inlet configuration. A modelisation taking into account wall heat pumping, enthalpy flow and regenerator inefficiency is under development. Preliminary calculation results are compared with experimental data

  8. Nonlinear coupled Alfven and gravitational waves

    International Nuclear Information System (INIS)

    Kaellberg, Andreas; Brodin, Gert; Bradley, Michael

    2004-01-01

    In this paper we consider nonlinear interaction between gravitational and electromagnetic waves in a strongly magnetized plasma. More specifically, we investigate the propagation of gravitational waves with the direction of propagation perpendicular to a background magnetic field and the coupling to compressional Alfven waves. The gravitational waves are considered in the high-frequency limit and the plasma is modeled by a multifluid description. We make a self-consistent, weakly nonlinear analysis of the Einstein-Maxwell system and derive a wave equation for the coupled gravitational and electromagnetic wave modes. A WKB-approximation is then applied and as a result we obtain the nonlinear Schroedinger equation for the slowly varying wave amplitudes. The analysis is extended to 3D wave pulses, and we discuss the applications to radiation generated from pulsar binary mergers. It turns out that the electromagnetic radiation from a binary merger should experience a focusing effect, that in principle could be detected

  9. Pulse to pulse klystron diagnosis system

    International Nuclear Information System (INIS)

    Nowak, J.; Davidson, V.; Genova, L.; Johnson, R.; Reagan, D.

    1981-03-01

    This report describes a system used to study the behavior of SLAC high powered klystrons operating with a twice normal pulse width of 5 μs. At present, up to eight of the klystrons installed along the accelerator can be operated with long pulses and monitored by this system. The report will also discuss some of the recent findings and investigations

  10. Heat Waves

    Science.gov (United States)

    Heat Waves Dangers we face during periods of very high temperatures include: Heat cramps: These are muscular pains and spasms due ... that the body is having trouble with the heat. If a heat wave is predicted or happening… - ...

  11. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

  12. Modeling ionization by helicon waves

    International Nuclear Information System (INIS)

    Degeling, A.W.; Boswell, R.W.

    1997-01-01

    The response of the electron distribution function in one dimension to a traveling wave electric field is modeled for parameters relevant to a low-pressure helicon wave plasma source, and the resulting change in the ionization rate calculated. This is done by calculating the trajectories of individual electrons in a given wave field and assuming no collisions to build up the distribution function as the distance from the antenna is increased. The ionization rate is calculated for argon by considering the ionization cross section and electron flux at a specified position and time relative to the left-hand boundary, where the distribution function is assumed to be Maxwellian and the wave travels to the right. The simulation shows pulses in the ionization rate that move away from the antenna at the phase velocity of the wave, demonstrating the effect of resonant electrons trapped in the wave close-quote s frame of reference. It is found that the ionization rate is highest when the phase velocity of the wave is between 2 and 3x10 6 m/s, where the electrons interacting strongly with the wave (i.e., electrons with velocities inside the wave close-quote s open-quotes trapping widthclose quotes) have initial energies just below the ionization threshold. Results from the model are compared with experimental data and show reasonable qualitative agreement. copyright 1997 American Institute of Physics

  13. Gravitational Waves

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Jonah Maxwell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-10-18

    This report has slides on Gravitational Waves; Pound and Rebka: A Shocking Fact; Light is a Ruler; Gravity is the Curvature of Spacetime; Gravitational Waves Made Simple; How a Gravitational Wave Affects Stuff Here; LIGO; This Detection: Neutron Stars; What the Gravitational Wave Looks Like; The Sound of Merging Neutron Stars; Neutron Star Mergers: More than GWs; The Radioactive Cloud; The Kilonova; and finally Summary, Multimessenger Astronomy.

  14. Wave phenomena

    CERN Document Server

    Towne, Dudley H

    1988-01-01

    This excellent undergraduate-level text emphasizes optics and acoustics, covering inductive derivation of the equation for transverse waves on a string, acoustic plane waves, boundary-value problems, polarization, three-dimensional waves and more. With numerous problems (solutions for about half). ""The material is superbly chosen and brilliantly written"" - Physics Today. Problems. Appendices.

  15. Electromagnetic Waves

    DEFF Research Database (Denmark)

    This book is dedicated to various aspects of electromagnetic wave theory and its applications in science and technology. The covered topics include the fundamental physics of electromagnetic waves, theory of electromagnetic wave propagation and scattering, methods of computational analysis......, material characterization, electromagnetic properties of plasma, analysis and applications of periodic structures and waveguide components, etc....

  16. Wave Dragon

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Frigaard, Peter; Sørensen, H. C.

    1998-01-01

    This paper concerns with the development of the wave energy converter (WEC) Wave Dragon. This WEC is based on the overtopping principle. An overview of the performed research done concerning the Wave Dragon over the past years is given, and the results of one of the more comprehensive studies, co...

  17. Response of a Hypersonic Boundary Layer to Freestream Pulse Acoustic Disturbance

    Directory of Open Access Journals (Sweden)

    Zhenqing Wang

    2014-01-01

    Full Text Available The response of hypersonic boundary layer over a blunt wedge to freestream pulse acoustic disturbance was investigated. The stability characteristics of boundary layer for freestream pulse wave and continuous wave were analyzed comparatively. Results show that freestream pulse disturbance changes the thermal conductivity characteristics of boundary layer. For pulse wave, the number of main disturbance clusters decreases and the frequency band narrows along streamwise. There are competition and disturbance energy transfer among different modes in boundary layer. The dominant mode of boundary layer has an inhibitory action on other modes. Under continuous wave, the disturbance modes are mainly distributed near fundamental and harmonic frequencies, while under pulse wave, the disturbance modes are widely distributed in different modes. For both pulse and continuous waves, most of disturbance modes slide into a lower-growth or decay state in downstream, which is tending towards stability. The amplitude of disturbance modes in boundary layer under continuous wave is considerably larger than pulse wave. The growth rate for the former is also considerably larger than the later the disturbance modes with higher growth are mainly distributed near fundamental and harmonic frequencies for the former, while the disturbance modes are widely distributed in different frequencies for the latter.

  18. Response of a hypersonic boundary layer to freestream pulse acoustic disturbance.

    Science.gov (United States)

    Wang, Zhenqing; Tang, Xiaojun; Lv, Hongqing

    2014-01-01

    The response of hypersonic boundary layer over a blunt wedge to freestream pulse acoustic disturbance was investigated. The stability characteristics of boundary layer for freestream pulse wave and continuous wave were analyzed comparatively. Results show that freestream pulse disturbance changes the thermal conductivity characteristics of boundary layer. For pulse wave, the number of main disturbance clusters decreases and the frequency band narrows along streamwise. There are competition and disturbance energy transfer among different modes in boundary layer. The dominant mode of boundary layer has an inhibitory action on other modes. Under continuous wave, the disturbance modes are mainly distributed near fundamental and harmonic frequencies, while under pulse wave, the disturbance modes are widely distributed in different modes. For both pulse and continuous waves, most of disturbance modes slide into a lower-growth or decay state in downstream, which is tending towards stability. The amplitude of disturbance modes in boundary layer under continuous wave is considerably larger than pulse wave. The growth rate for the former is also considerably larger than the later the disturbance modes with higher growth are mainly distributed near fundamental and harmonic frequencies for the former, while the disturbance modes are widely distributed in different frequencies for the latter.

  19. Optical Pulsing in an Absorbing Liquid

    Science.gov (United States)

    Barnes, Jacob; Evans, Dean; Guha, Shekhar

    2003-03-01

    A continuous-wave laser can be converted into a series of repetitive pulses by focusing the laser beam into an absorbing liquid (e.g. nigrosine dissolved in a solvent), where the mechanism responsible for the pulses is the scattering of light off of photo-generated bubbles. The dependence of the pulsation frequency on the solvent, power, and cell thickness will be shown. The authors would like to acknowledge the contributions made by Prof. Daniel Lathrop (University of Maryland, Department of Physics) at the APS March 2002 meeting.

  20. Terahertz waves radiated from two noncollinear femtosecond plasma filaments

    Energy Technology Data Exchange (ETDEWEB)

    Du, Hai-Wei; Hoshina, Hiromichi; Otani, Chiko, E-mail: otani@riken.jp [Terahertz Sensing and Imaging Research Team, RIKEN Center for Advanced Photonics, RIKEN, Sendai, Miyagi 980-0845 (Japan); Midorikawa, Katsumi [Attosecond Science Research Team, RIKEN Center for Advanced Photonics, RIKEN, Wako, Saitama 351-0198 (Japan)

    2015-11-23

    Terahertz (THz) waves radiated from two noncollinear femtosecond plasma filaments with a crossing angle of 25° are investigated. The irradiated THz waves from the crossing filaments show a small THz pulse after the main THz pulse, which was not observed in those from single-filament scheme. Since the position of the small THz pulse changes with the time-delay of two filaments, this phenomenon can be explained by a model in which the small THz pulse is from the second filament. The denser plasma in the overlap region of the filaments changes the movement of space charges in the plasma, thereby changing the angular distribution of THz radiation. As a result, this schematic induces some THz wave from the second filament to propagate along the path of the THz wave from the first filament. Thus, this schematic alters the direction of the THz radiation from the filamentation, which can be used in THz wave remote sensing.

  1. Calcium waves.

    Science.gov (United States)

    Jaffe, Lionel F

    2008-04-12

    Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

  2. Wave turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Nazarenko, Sergey [Warwick Univ., Coventry (United Kingdom). Mathematics Inst.

    2011-07-01

    Wave Turbulence refers to the statistical theory of weakly nonlinear dispersive waves. There is a wide and growing spectrum of physical applications, ranging from sea waves, to plasma waves, to superfluid turbulence, to nonlinear optics and Bose-Einstein condensates. Beyond the fundamentals the book thus also covers new developments such as the interaction of random waves with coherent structures (vortices, solitons, wave breaks), inverse cascades leading to condensation and the transitions between weak and strong turbulence, turbulence intermittency as well as finite system size effects, such as ''frozen'' turbulence, discrete wave resonances and avalanche-type energy cascades. This book is an outgrow of several lectures courses held by the author and, as a result, written and structured rather as a graduate text than a monograph, with many exercises and solutions offered along the way. The present compact description primarily addresses students and non-specialist researchers wishing to enter and work in this field. (orig.)

  3. Propagation of a femtosecond laser pulse with duration of several optical oscillation periods in a medium with a quadratic nonlinearity

    International Nuclear Information System (INIS)

    Akopyan, A A; Oganesyan, D L

    1998-01-01

    It is shown that the wave equation can be solved by the method of unidirectional waves for a pulse with a duration of several oscillation periods in a medium with a quadratic nonlinearity, such as a group-3m crystal. The wave equation reduces to a system of two equations for waves with different polarisations. (laser applications and other topics in quantum electronics)

  4. Association between Urine Creatinine Excretion and Arterial Stiffness in Chronic Kidney Disease: Data from the KNOW-CKD Study

    Directory of Open Access Journals (Sweden)

    Young Youl Hyun

    2016-08-01

    Full Text Available Background/Aims: Previous studies have shown that low muscle mass is associated with arterial stiffness, as measured by pulse wave velocity (PWV, in a population without chronic kidney disease (CKD. This link between low muscle mass and arterial stiffness may explain why patients with CKD have poor cardiovascular outcomes. However, the association between muscle mass and arterial stiffness in CKD patients is not well known. Methods: Between 2011 and 2013, 1,529 CKD patients were enrolled in the prospective Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD. We analyzed 888 participants from this cohort who underwent measurements of 24-hr urinary creatinine excretion (UCr and brachial-ankle PWV (baPWV at baseline examination. The mean of the right and left baPWV (mPWV was used as a marker of arterial stiffness. Results: The baPWV values varied according to the UCr quartile (1,630±412, 1,544±387, 1,527±282 and 1,406±246 for the 1st to 4th quartiles of UCr, respectively, PConclusion: Low muscle mass estimated by low UCr was associated high baPWV in pre-dialysis CKD patients in Korea. Further studies are needed to confirm the causal relationship between UCR and baPWV, and the role of muscle mass in the development of cardiovascular disease in CKD.

  5. Relationship between uric acid and arterial stiffness in the elderly with metabolic syndrome components.

    Science.gov (United States)

    Sun, Ning; Zhang, Yun; Tian, Jian-li; Wang, Hui

    2013-08-01

    High uric acid (UA) levels and metabolic syndrome (MS) are risk factors for atherosclerotic diseases. Brachial-ankle pulse wave velocity (baPWV) is a valid and reproducible measurement by which to assess arterial stiffness and a surrogate marker of atherosclerosis. However, little is known about the relationship between them, especially in elderly Chinese with MS components who are at high risk for atherosclerotic diseases. One thousand and twenty Chinese subjects (159 women) older than 60 years of age (mean age (70.6 ± 5.7) years) with at least one MS component underwent routine laboratory tests, and baPWV measurements were analyzed. Participants were divided into four groups by MS components. The mean age did not significantly differ among the MS component groups. We found that not only the diagnostic factors (blood pressure, body mass index (BMI), lipids, glucose) of MS but also baPWV, UA, insulin, homeostasis model of assessment for insulin resistence index (HOMAIR) levels increased, and high density lipoprotein (HDL)-C decreased with an increased number of MS components (test for trend P insulin resistance (r = 0.186, P insulin or HOMA-IR, there were no significant differences in the multivariate odds ratios among the number of MS components for UA. The UA level is positively associated with baPWV and MS, but the association between UA and MS is dependent on insulin resistance. Furthermore, baPWV is independently associated with MS in our study population.

  6. Whole-body vibration exercise training reduces arterial stiffness in postmenopausal women with prehypertension and hypertension.

    Science.gov (United States)

    Figueroa, Arturo; Kalfon, Roy; Madzima, Takudzwa A; Wong, Alexei

    2014-02-01

    The purpose of this study was to examine the impact of whole-body vibration (WBV) exercise training on arterial stiffness (pulse wave velocity [PWV]), blood pressure (BP), and leg muscle function in postmenopausal women. Twenty-five postmenopausal women with prehypertension and hypertension (mean [SE]; age, 56 [1] y; systolic BP, 139 [2] mm Hg; body mass index, 34.7 [0.8] kg/m2) were randomized to 12 weeks of WBV exercise training (n = 13) or to the no-exercise control group. Systolic BP, diastolic BP, mean arterial pressure, heart rate, carotid-femoral PWV, brachial-ankle PWV, femoral-ankle PWV (legPWV), leg lean mass, and leg muscle strength were measured before and after 12 weeks. There was a group-by-time interaction (P exercise training compared with no change after control. Heart rate decreased (-3 [1] beats/min, P exercise training, but there was no interaction (P > 0.05). Leg lean mass and carotid-femoral PWV were not significantly (P > 0.05) affected by WBV exercise training or control. Our findings indicate that WBV exercise training improves systemic and leg arterial stiffness, BP, and leg muscle strength in postmenopausal women with prehypertension or hypertension. WBV exercise training may decrease cardiovascular and disability risks in postmenopausal women by reducing legPWV and increasing leg muscle strength.

  7. Does aerobic exercise mitigate the effects of cigarette smoking on arterial stiffness?

    Science.gov (United States)

    Park, Wonil; Miyachi, Motohiko; Tanaka, Hirofumi

    2014-09-01

    The largest percentage of mortality from tobacco smoking is cardiovascular-related. It is not known whether regular participation in exercise mitigates the adverse influence of smoking on vasculature. Accordingly, the authors determined whether regular aerobic exercise is associated with reduced arterial stiffness in men who smoke cigarettes. Using a cross-sectional study design, 78 young men were studied, including sedentary nonsmokers (n=20), sedentary smokers (n=12), physically active nonsmokers (n=21), and physically active smokers (n=25). Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV). There were no group differences in height, body fat, and systolic and diastolic blood pressure. As expected, both physically active groups demonstrated greater maximal oxygen consumption and lower heart rate at rest than their sedentary peers. The sedentary smokers demonstrated greater baPWV than the sedentary nonsmokers (11.8±1 m/s vs 10.6±1 m/s, P=.036). baPWV values were not different between the physically active nonsmokers and the physically active smokers (10.8±1 m/s vs 10.7±1 m/s). Chronic smoking is associated with arterial stiffening in sedentary men but a significant smoking-induced increase in arterial stiffness was not observed in physically active adults. These results are consistent with the idea that regular participation in physical activity may mitigate the adverse effects of smoking on the vasculature. ©2014 Wiley Periodicals, Inc.

  8. Visceral adiposity index may be a surrogate marker for the assessment of the effects of obesity on arterial stiffness.

    Directory of Open Access Journals (Sweden)

    Fan Yang

    Full Text Available The relationship between obesity and cardiovascular disease (CVD remains unclear. This study aims to describe the relationship between arterial stiffness and obesity in order to investigate the effects of obesity on CVD.We collected data from 5,158 individuals over 40 years of age from a cross-sectional study in Nanjing, China. Anthropometric, demographic, hemodynamic measurements and arterial stiffness measured through brachial-ankle pulse wave velocity (baPWV were obtained. Subjects were grouped by body mass index (BMI, waist circumference (WC and visceral adiposity index (VAI, a sex-specific index based on BMI, WC, triglyceride (TG and high-density lipoprotein cholesterol (HDL-C.The multivariate regression analysis revealed a negative but weak effect of BMI (β = -0.047, P0.05, it was still obtained between baPWV and VAI quartile (P0.05. However, baPWV significantly increased across groups with higher VAI categories even in the same metabolic category (P<0.01.This study supports the concept of heterogeneity of metabolic status among individuals within the same obesity range. Obese individuals are at an increased risk of arterial stiffness regardless of their metabolic conditions. VAI may be a surrogate marker for the assessment of obesity and the effects of obesity on arterial stiffness.

  9. Fitness as a determinant of arterial stiffness in healthy adult men: a cross-sectional study.

    Science.gov (United States)

    Chung, Jinwook; Kim, Milyang; Jin, Youngsoo; Kim, Yonghwan; Hong, Jeeyoung

    2018-01-01

    Fitness is known to influence arterial stiffness. This study aimed to assess differences in cardiorespiratory endurance, muscular strength, and flexibility according to arterial stiffness, based on sex and age. We enrolled 1590 healthy adults (men: 1242, women: 348) who were free of metabolic syndrome. We measured cardiorespiratory endurance in an exercise stress test on a treadmill, muscular strength by a grip test, and flexibility by upper body forward-bends from a standing position. The brachial-ankle pulse wave velocity test was performed to measure arterial stiffness before the fitness test. Cluster analysis was performed to divide the patients into groups with low (Cluster 1) and high (Cluster 2) arterial stiffness. According to the k-cluster analysis results, Cluster 1 included 624 men and 180 women, and Cluster 2 included 618 men and 168 women. Men in the middle-aged group with low arterial stiffness demonstrated higher cardiorespiratory endurance, muscular strength, and flexibility than those with high arterial stiffness. Similarly, among men in the old-aged group, the cardiorespiratory endurance and muscular strength, but not flexibility, differed significantly according to arterial stiffness. Women in both clusters showed similar cardiorespiratory endurance, muscular strength, and flexibility regardless of their arterial stiffness. Among healthy adults, arterial stiffness was inversely associated with fitness in men but not in women. Therefore, fitness seems to be a determinant for arterial stiffness in men. Additionally, regular exercise should be recommended for middle-aged men to prevent arterial stiffness.

  10. Effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness of female patients with metabolic syndrome.

    Science.gov (United States)

    Kang, Seol-Jung; Kim, Eon-Ho; Ko, Kwang-Jun

    2016-06-01

    [Purpose] The purpose of this study was to investigate the effects of aerobic exercise on the resting heart rate, physical fitness, and arterial stiffness or female patients with metabolic syndrome. [Subjects and Methods] Subjects were randomly assigned to an exercise group (n=12) or a control group (n=11). Subjects in the exercise group performed aerobic exercise at 60-80% of maximum heart rate for 40 min 5 times a week for 12 weeks. The changes in metabolic syndrome risk factors, resting heart rate, physical fitness, and arterial stiffness were measured and analyzed before and after initiation of the exercise program to determine the effect of exercise. Arterial stiffness was assessed based on brachial-ankle pulse wave velocity (ba-PWV). [Results] Compared to the control group; The metabolic syndrome risk factors (weight, % body fat, waist circumference, systolic blood pressure, diastolic blood pressure, and HDL-Cholesterol) were significantly improved in the exercise: resting heart rate was significantly decreased; VO2max, muscle strength and muscle endurance were significantly increased; and ba-PWV was significantly decreased. [Conclusion] Aerobic exercise had beneficial effects on the resting heart rate, physical fitness, and arterial stiffness of patients with metabolic syndrome.

  11. Combined resistance and endurance exercise training improves arterial stiffness, blood pressure, and muscle strength in postmenopausal women.

    Science.gov (United States)

    Figueroa, Arturo; Park, Song Y; Seo, Dae Y; Sanchez-Gonzalez, Marcos A; Baek, Yeong H

    2011-09-01

    Menopause is associated with increased arterial stiffness and reduced muscle strength. Combined resistance (RE) and endurance (EE) exercise training can decrease brachial-ankle pulse wave velocity (baPWV), an index of arterial stiffness, in young men. We tested the hypothesis that combined circuit RE and EE training would improve baPWV, blood pressure (BP), and muscle strength in postmenopausal women. Twenty-four postmenopausal women (age 47-68 y) were randomly assigned to a "no exercise" control (n = 12) or to combined exercise training (EX; n = 12) group. The EX group performed concurrent circuit RE training followed by EE training at 60% of the predicted maximal heart rate (HR) 3 days per week. Brachial systolic BP, diastolic BP, mean arterial pressure, baPWV, HR, and dynamic and isometric muscle strength were measured before and after the 12-week study. Mean ± SE baPWV (-0.8 ± 0.2 meters/s), systolic BP (-6.0 ± 1.9 mm Hg), diastolic BP (-4.8 ± 1.7 mm Hg), HR (-4.0 ± 1.0 beats/min), and mean arterial pressure (-5.1 ± 1.6 mm Hg) decreased (P hypertension and frailty in postmenopausal women.

  12. Association of Interarm Systolic Blood Pressure Difference with Atherosclerosis and Left Ventricular Hypertrophy

    Science.gov (United States)

    Su, Ho-Ming; Lin, Tsung-Hsien; Hsu, Po-Chao; Chu, Chun-Yuan; Lee, Wen-Hsien; Chen, Szu-Chia; Lee, Chee-Siong; Voon, Wen-Chol; Lai, Wen-Ter; Sheu, Sheng-Hsiung

    2012-01-01

    An interarm systolic blood pressure (SBP) difference of 10 mmHg or more have been associated with peripheral artery disease and adverse cardiovascular outcomes. We investigated whether an association exists between this difference and ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), and echocardiographic parameters. A total of 1120 patients were included in the study. The bilateral arm blood pressures were measured simultaneously by an ABI-form device. The values of ABI and baPWV were also obtained from the same device. Clinical data, ABIdifference ≥10 mmHg were compared and analyzed. We performed two multivariate forward analyses for determining the factors associated with an interarm SBP difference ≥10 mmHg [model 1: significant variables in univariate analysis except left ventricular mass index (LVMI); model 2: significant variables in univariate analysis except ABIdifference ≥10 mmHg. Female, hypertension, and high body mass index were also associated with an interarm SBP difference ≥10 mmHg. Our study demonstrated that ABIdifference of 10 mmHg or more. Detection of an interarm SBP difference may provide a simple method of detecting patients at increased risk of atherosclerosis and left ventricular hypertrophy. PMID:22927905

  13. The Effects of a Motorized Aquatic Treadmill Exercise Program on Muscle Strength, Cardiorespiratory Fitness, and clinical function in Subacute Stroke Patients -- a Randomized Controlled Pilot Trial.

    Science.gov (United States)

    Lee, So Young; Han, Eun Young; Kim, Bo Ryun; Im, Sang Hee

    2018-03-12

    The aim of this study was to assess the effects of a motorized aquatic treadmill exercise program improve the isometric strength of the knee muscles, cardiorespiratory fitness, arterial stiffness, motor function, balance, functional outcomes and quality of life in subacute stroke patients. Thirty-two patients were randomly assigned to 4-week training sessions of either aquatic therapy(n=19) or land-based aerobic exercise(n=18). Isometric strength was measured using an isokinetic dynamometer. Cardiopulmonary fitness was evaluated using a symptom-limited exercise tolerance test and by measuring brachial ankle pulse wave velocity. Moreover, motor function(Fugl-Meyer Assessment[FMA] and FMA-lower limb[FMA-LL]), balance(Berg Balance Scale[BBS]), Activities of daily living(Korean version of the Modified Barthel Index [K-MBI]), and Quality of life(EQ-5D index) were examined. There were no inter-group differences between demographic and clinical characteristics at baseline(p>0.05). The results shows significant improvements in peak oxygen consumption (p=0.02), maximal isometric strength of the bilateral knee extensors (paquatic therapy group. However, only significant improvements in maximal isometric strength in the knee extensors (p=0.03) and flexors (p=0.04) were found within the aquatic therapy group and control group. Water-based aerobic exercise performed on a motorized aquatic treadmill had beneficial effect on isometric muscle strength in the lower limb.

  14. Arterial Stiffness is an Independent Risk Factor for Anemia After Percutaneous Native Kidney Biopsy

    Directory of Open Access Journals (Sweden)

    Keiko Tanaka

    2017-05-01

    Full Text Available Background/Aims: Bleeding is the most common complication after renal biopsy. Although numerous predictors of bleeding have been reported, it remains unclear whether arterial stiffness affects bleeding complications. Method: We performed an observational study of the renal biopsies performed in our division over an approximately 6-year period (May 2010 to May 2016. The clinical and laboratory factors were analyzed to reveal the risk factors associated with bleeding, with a focus on anemia (defined as a ≥10% decrease in hemoglobin [Hb] after biopsy. The brachial-ankle pulse wave velocity (baPWV was measured to evaluate arterial stiffness. Results: This study included 462 patients (male, n=244; female, n=218. Anemia (defined above was observed in 54 patients (11.7%. The risk of anemia was higher in women, older patients, and patients with lower serum albumin, lower eGFR and lower diastolic blood pressure after biopsy. We then performed a further analysis of 187 patients whose baPWV data were available. Multivariate analysis revealed that a higher baPWV was an independent risk factor for anemia. ROC analysis for predicting anemia found that a baPWV value of 1839 cm/s had the best performance (AUC 0.689. Conclusion: An increased baPWV may be a more valuable predictor of bleeding than any of the other reported risk factors.

  15. Significance of measuring oxidative stress in lifestyle-related diseases from the viewpoint of correlation between d-ROMs and BAP in Japanese subjects

    International Nuclear Information System (INIS)

    Fukui, Toshiki; Yamauchi, Kazuhiro; Maruyama, Mie; Yasuda, Tadashi; Abe, Youichi; Kohno, Masakazu

    2011-01-01

    In recent years, oxidative stress has been postulated to be an important factor in the pathogenesis and development of lifestyle-related diseases. In this study, we investigated the association between the derivatives of reactive oxygen metabolites (d-ROMs), as an index of products of reactive oxygen species (ROS), and biological antioxidant potential (BAP), as an index of antioxidant potential. We also investigated the associations between d-ROMs or BAP and the risk factors for lifestyle-related diseases or metabolic syndrome-associated factors to evaluate their usefulness in preventive medicine. There were 442 subjects who underwent health checkup examination in our facilities. In addition to standard medical checkup items, we analyzed d-ROMs, BAP, brachial-ankle pulse wave velocity, high-sensitivity C-reactive protein level and visceral fat area (VFA) visualized on a computed tomography scan. The mean d-ROM value in females was significantly higher than that in males. There was a positive correlation between the d-ROM and VFA levels. On correlation analysis, there was a negative correlation between the d-ROM and creatinine levels. As factors that influence d-ROMs, the level of VFA was selected, suggesting the significance of oxidative stress measurement with d-ROMs. In addition, there was a positive correlation between d-ROMs and BAP values. Further research is required to resolve whether increased production of ROS or the antioxidant potential that can compensate for such an increase of ROS is more important in vivo. (author)

  16. Low Levels of Sex Hormone-Binding Globulin Constitute an Independent Risk Factor for Arterial Stiffness in Korean Women

    Directory of Open Access Journals (Sweden)

    Kunhee Han

    2017-01-01

    Full Text Available The association between sex hormone-binding globulin (SHBG and arterial stiffness in women is not conclusive. In addition, obesity might also be involved in the relationship between SHBG and atherosclerosis. The aim of this study was to determine the relationship between SHBG and arterial stiffness in association with central obesity in women. This cross-sectional study included 381 women who participated in the health checkup programs in one hospital. The brachial-ankle pulse wave velocity (baPWV was measured as a marker for arterial stiffness. A negative correlation was observed between SHBG levels and baPWV (rho = −0.281. The relationship was significant even after adjusting for potential confounders (beta = −0.087 in fully adjusted model. After considering the interaction between central obesity and SHBG levels, the significant association was evident only in obese women (P for interaction = 0.025. Adjustment for a 10-year atherosclerotic cardiovascular disease (ASCVD risk scores, instead of each cardiovascular risk factor individually, did not affect the significance of the relationship between SHBG levels and baPWV. Serum levels of SHBG were negatively associated with arterial stiffness independent of cardiovascular risk factors or 10-year ASCVD risk scores in Korean women. The relationship may be potentiated by central obesity.

  17. Cardiovascular Risk Factors and Distributions of the Ankle-Brachial Index among Type 2 Diabetes Mellitus Patients

    Directory of Open Access Journals (Sweden)

    Badaruddoza Doza

    2012-01-01

    Full Text Available Background. The aim of present study is to observe the association between the levels of ankle-brachial index (ABI and cardiovascular risk factors among people with type 2 diabetes mellitus in north India. A cross-sectional study was carried out at a centre for heart and diabetic clinic in the state of Punjab on 1121 subjects (671 males and 450 females with type 2 diabetes mellitus. History of symptoms related to cardiovascular diseases was noted, and blood pressure and anthropometric measurements were recorded. Ankle-brachial index (ABI was measured using ultrasonic Doppler flow detector. Subjects with ABI ≤0.9 and ≥1.30 were classified as having low and high ABI, respectively. Females had a higher BMI and brachial-ankle pulse wave velocity (<0.001. Whereas, males had higher diastolic blood pressure and duration of type 2 diabetes mellitus. The differences of systolic blood pressure and ankle-brachial index were not found significant between the sexes. The prevalence of low ABI (<0.9 was 4.47% in men and 4.67% in women and high ABI (≥1.30 was prevalent in 14% of men and 10.45% of women. Age, BMI, baPWV, and blood pressures were significantly associated with ABI value in both sexes. The results suggested that the ABI might be used as a strong indicator for cardiovascular risk factors in type 2 diabetic subjects.

  18. Axial gravitational waves in FLRW cosmology and memory effects

    Science.gov (United States)

    Kulczycki, Wojciech; Malec, Edward

    2017-09-01

    We show initial data for gravitational axial waves that are twice differentiable but that are not C2. They generate wave pulses that interact with matter in the radiation cosmological era. This forces the radiation matter to rotate. This rotation is permanent—it persists after the passage of the gravitational pulse. The observed inhomogeneities of the cosmic microwave background radiation put a bound onto discontinuities of superhorizon metric perturbations. We explicitly show that a class of smooth initial metrics that are at least C2 gives rise to gravitational wave pulses that do not interact with the background during the radiation epoch.

  19. Optical wave microphone measurement during laser ablation of Si

    Energy Technology Data Exchange (ETDEWEB)

    Mitsugi, Fumiaki, E-mail: mitsugi@cs.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto, 860-8555 (Japan); Ide, Ryota; Ikegami, Tomoaki [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto, 860-8555 (Japan); Nakamiya, Toshiyuki; Sonoda, Yoshito [Graduate School of Industrial Engineering, Tokai University, 9-1-1 Toroku, Kumamoto, 862-8652 (Japan)

    2012-10-30

    Pulsed laser irradiation is used for surface treatment of a solid and ablation for particle formation in gas, liquid or supercritical phase media. When a pulsed laser is used to irradiate a solid, spatial refractive index variations (including photothermal expansion, shockwaves and particles) occur, which vary depending on the energy density of the pulsed laser. We focused on this phenomenon and applied an unique method for detection of refractive index variation using an optical wave microphone based on Fraunhofer diffraction. In this research, we analyzed the waveforms and frequencies of refractive index variations caused by pulsed laser irradiation of silicon in air and measured with an optical wave microphone.

  20. Focusing Leaky Waves: A Class of Electromagnetic Localized Waves with Complex Spectra

    Science.gov (United States)

    Fuscaldo, Walter; Comite, Davide; Boesso, Alessandro; Baccarelli, Paolo; Burghignoli, Paolo; Galli, Alessandro

    2018-05-01

    Localized waves, i.e., the wide class of limited-diffraction, limited-dispersion solutions to the wave equation are generally characterized by real wave numbers. We consider the role played by localized waves with generally complex "leaky" wave numbers. First, the impact of the imaginary part of the wave number (i.e., the leakage constant) on the diffractive (spatial broadening) features of monochromatic localized solutions (i.e., beams) is rigorously evaluated. Then general conditions are derived to show that only a restricted class of spectra (either real or complex) allows for generating a causal localized wave. It turns out that backward leaky waves fall into this category. On this ground, several criteria for the systematic design of wideband radiators, namely, periodic radial waveguides based on backward leaky waves, are established in the framework of leaky-wave theory. An effective design method is proposed to minimize the frequency dispersion of the proposed class of devices and the impact of the "leakage" on the dispersive (temporal broadening) features of polychromatic localized solutions (i.e., pulses) is accounted for. Numerical results corroborate the concept, clearly highlighting the advantages and limitations of the leaky-wave approach for the generation of localized pulses at millimeter-wave frequencies, where energy focusing is in high demand in modern applications.