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  1. A Non-Parametric Surrogate-based Test of Significance for T-Wave Alternans Detection

    Science.gov (United States)

    Nemati, Shamim; Abdala, Omar; Bazán, Violeta; Yim-Yeh, Susie; Malhotra, Atul; Clifford, Gari

    2010-01-01

    We present a non-parametric adaptive surrogate test that allows for the differentiation of statistically significant T-Wave Alternans (TWA) from alternating patterns that can be solely explained by the statistics of noise. The proposed test is based on estimating the distribution of noise induced alternating patterns in a beat sequence from a set of surrogate data derived from repeated reshuffling of the original beat sequence. Thus, in assessing the significance of the observed alternating patterns in the data no assumptions are made about the underlying noise distribution. In addition, since the distribution of noise-induced alternans magnitudes is calculated separately for each sequence of beats within the analysis window, the method is robust to data non-stationarities in both noise and TWA. The proposed surrogate method for rejecting noise was compared to the standard noise rejection methods used with the Spectral Method (SM) and the Modified Moving Average (MMA) techniques. Using a previously described realistic multi-lead model of TWA, and real physiological noise, we demonstrate the proposed approach reduces false TWA detections, while maintaining a lower missed TWA detection compared with all the other methods tested. A simple averaging-based TWA estimation algorithm was coupled with the surrogate significance testing and was evaluated on three public databases; the Normal Sinus Rhythm Database (NRSDB), the Chronic Heart Failure Database (CHFDB) and the Sudden Cardiac Death Database (SCDDB). Differences in TWA amplitudes between each database were evaluated at matched heart rate (HR) intervals from 40 to 120 beats per minute (BPM). Using the two-sample Kolmogorov-Smirnov test, we found that significant differences in TWA levels exist between each patient group at all decades of heart rates. The most marked difference was generally found at higher heart rates, and the new technique resulted in a larger margin of separability between patient populations than

  2. An Open-Source Standard T-Wave Alternans Detector for Benchmarking.

    Science.gov (United States)

    Khaustov, A; Nemati, S; Clifford, Gd

    2008-09-14

    We describe an open source algorithm suite for T-Wave Alternans (TWA) detection and quantification. The software consists of Matlab implementations of the widely used Spectral Method and Modified Moving Average with libraries to read both WFDB and ASCII data under windows and Linux. The software suite can run in both batch mode and with a provided graphical user interface to aid waveform exploration. Our software suite was calibrated using an open source TWA model, described in a partner paper [1] by Clifford and Sameni. For the PhysioNet/CinC Challenge 2008 we obtained a score of 0.881 for the Spectral Method and 0.400 for the MMA method. However, our objective was not to provide the best TWA detector, but rather a basis for detailed discussion of algorithms.

  3. T-wave alternans, air pollution and traffic in high-risk subjects.

    Science.gov (United States)

    Zanobetti, Antonella; Stone, Peter H; Speizer, Frank E; Schwartz, Joel D; Coull, Brent A; Suh, Helen H; Nearing, Bruce D; Mittleman, Murray A; Verrier, Richard L; Gold, Diane R

    2009-09-01

    Particulate pollution has been linked to risk for cardiac death; possible mechanisms include pollution-related increases in cardiac electrical instability. T-wave alternans (TWA) is a marker of cardiac electrical instability measured as differences in the magnitude between adjacent T waves. In a repeated-measures study of 48 patients aged 43 to 75 years, associations of ambient and home indoor particulate pollution, including black carbon (BC) and reports of traffic exposure, with changes in 0.5-hourly maximum TWA (TWA-MAX), measured by 24-hour Holter electrocardiographic monitoring, were investigated. Each patient was observed up to 4 times within 1 year after percutaneous intervention for myocardial infarction, acute coronary syndromes without infarction, or stable coronary artery disease, for a total of 5,830 0.5-hour observations. Diary data for each 0.5-hour period defined whether a patient was home or not home, or in traffic. Increases in TWA-MAX were independently associated with the previous 2-hour mean ambient BC (2.1%, 95% confidence interval 0.9% to 3.3%) and with being in traffic in the previous 2 hours (6.1%, 95% confidence interval 3.4% to 8.8%). When subjects were home, indoor home BC effects were largest and most precise; when subjects were away from home, ambient central site BC effects were strongest. Increases in pollution increased the odds of TWA-MAX > or =75th percentile (odds ratio 1.4, 95% confidence interval 1.2 to 1.6 for a 1 microg/m(3) increase in 6-hour mean BC). In conclusion, after hospitalization for coronary artery disease, being in traffic and short-term ambient or indoor BC exposure increased TWA, a marker of cardiac electrical instability.

  4. Suggestions To Evaluate Whether T-wave Alternans Is T-wave Amplitude Dependent

    Directory of Open Access Journals (Sweden)

    John E. Madias

    2009-03-01

    Full Text Available -wave alternans (TWA has been employed in the selection of patients considered for cardioverter/defibrillator (ICD implantation, and has been found to have an excellent negative predictive value for sudden death and malignant ventricular arrhythmias in patients with a variety of cardiac pathologies [1]. Although a qualitative approach in the characterization of patients with TWA positive or negative results has prevailed, based on a threshold of ≥1.9 μV, attained during exercise stress testing, employing the frequency domain analysis [2], some have advanced the argument that employment of TWA in quantitative terms may have advantages [3,4]. Indeed even the currently employed qualitative (yes or no spectral analysis method with the ≥1.9 μV threshold value has a quantitative underpinning, in the sense that non attainment of the threshold value of ≥1.9 μV renders the patient's test negative [2]. Intuitively the magnitude of TWA must be of importance not only because a particular threshold needs to be reached, before the patient is considered positive, but because pathophysiological derangements (e.g., ischemia, volume overload, or myocardial necrosis result in an increase of the magnitude of TWA or an association of the magnitude of the TWA and the severity of derangement [5-7], while therapeutic interventions (e.g. beta-blockers lead to a decrease in the magnitude of TWA [8].

  5. A simulation of T-wave alternans vectocardiographic representation performed by changing the ventricular heart cells action potential duration.

    Science.gov (United States)

    Janusek, D; Kania, M; Zaczek, R; Zavala-Fernandez, H; Maniewski, R

    2014-04-01

    The presence of T wave alternans (TWA) in the surface ECG signals has been recognized as a marker of electrical instability, and is hypothesized to be related to patients at increased risk for ventricular arrhythmias. In this paper we present a TWA simulation study. The TWA phenomenon was simulated by changing the duration of the ventricular heart cells action potential. The magnitude was calculated in the surface ECG with the use of the time domain method. The spatially concordant TWA, where during one heart beat all ventricular cells display a short-duration action potential and during the next beat they exhibit a long-duration action potential, as well as the discordant TWA, where at least one region is out of phase, was simulated. The vectocardiographic representation was employed. The obtained results showed a high level of T-loop pattern and location disturbances connected to the discordant TWA simulation in contrast to the concordant one. This result may be explained by the spatial heterogeneity of the ventricular repolarization process, which could be higher for the discordant TWA than for the concordant TWA. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  6. T wave alternans threshold late after repair of tetralogy of Fallot

    Science.gov (United States)

    Cheung, Michael M H.; Weintraub, Robert G.; Cohen, Richard J.; Karl, Tom R.; Wilkinson, James L.; Davis, Andrew M.

    2002-01-01

    INTRODUCTION: Sustained microvolt-level T wave alternans (TWA) is a marker of increased risk for malignant ventricular arrhythmia. There is a significant risk of arrhythmia and sudden death after repair of congenital heart disease. The aim of this study was to determine the prevalence and characteristics of TWA after repair of tetralogy of Fallot (TOF). METHODS AND RESULTS: TWA was evaluated during bicycle exercise in 49 subjects who had consecutively undergone transatrial-transpulmonary repair. Median values for age, age at repair, and follow-up duration were 14.9 years (11.5-20.8), 1.6 years (0.2-4.9), and 11.6 years (9.4-17.2), respectively. All patients were in New York Heart Association functional class I and were asymptomatic. Median QRS duration was 120 msec (80-150). Sustained TWA was detected in 7 (23%) of 31 subjects with adequate tests. In these 7 subjects, median onset heart rate (HR) was 120 (98-155). Median HR threshold as a percentage of predicted maximum HR (220 - age) was 58% (48-77). Sustained TWA prevalence was not significantly different compared with normal subjects (7/31 vs 9/83; P = 0.1). Onset HR in the TOF group was significantly lower [mean (SD) of 122 (20) vs 139 (12), P < 0.05]. In the TOF group with sustained TWA, the TWA occurred in 4 of 7 at <60% predicted maximum HR versus 1 of 9 normal subjects (P < 0.05); 3 of 7 had onset HR <120 versus 0 of 9 normal subjects (P < 0.03). There was no significant difference in age, gender, transannular patch use, restrictive right ventricular physiology, QRS duration, QTc, QT/QRS dispersion, or nonsustained ventricular tachycardia in subjects with or those without sustained TWA. CONCLUSION: The onset HR for sustained TWA is significantly lower after repair of TOF. Further study is required to determine whether this represents an increased risk for arrhythmia in this patient group.

  7. Benchmarking of a T-wave alternans detection method based on empirical mode decomposition.

    Science.gov (United States)

    Blanco-Velasco, Manuel; Goya-Esteban, Rebeca; Cruz-Roldán, Fernando; García-Alberola, Arcadi; Rojo-Álvarez, José Luis

    2017-07-01

    T-wave alternans (TWA) is a fluctuation of the ST-T complex occurring on an every-other-beat basis of the surface electrocardiogram (ECG). It has been shown to be an informative risk stratifier for sudden cardiac death, though the lack of gold standard to benchmark detection methods has promoted the use of synthetic signals. This work proposes a novel signal model to study the performance of a TWA detection. Additionally, the methodological validation of a denoising technique based on empirical mode decomposition (EMD), which is used here along with the spectral method, is also tackled. The proposed test bed system is based on the following guidelines: (1) use of open source databases to enable experimental replication; (2) use of real ECG signals and physiological noise; (3) inclusion of randomized TWA episodes. Both sensitivity (Se) and specificity (Sp) are separately analyzed. Also a nonparametric hypothesis test, based on Bootstrap resampling, is used to determine whether the presence of the EMD block actually improves the performance. The results show an outstanding specificity when the EMD block is used, even in very noisy conditions (0.96 compared to 0.72 for SNR = 8 dB), being always superior than that of the conventional SM alone. Regarding the sensitivity, using the EMD method also outperforms in noisy conditions (0.57 compared to 0.46 for SNR=8 dB), while it decreases in noiseless conditions. The proposed test setting designed to analyze the performance guarantees that the actual physiological variability of the cardiac system is reproduced. The use of the EMD-based block in noisy environment enables the identification of most patients with fatal arrhythmias. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Comparison of T wave alternans in patients with cardiomyopathy and healthy controls

    International Nuclear Information System (INIS)

    Hira, A.; Khan, M. A.; Hayat, A.

    2017-01-01

    Objective: To compare T wave alternans in patients with cardiomyopathy and healthy controls. Study Design: Cross-sectional comparative study. Place and Duration of Study: Department of Cardiac Electrophysiology, Armed Forces Institute of Cardiology Rawalpindi, from Feb 2016 to Aug 2016. Material and Methods: Sixty patients with cardiomyopathy (any type) along with sixty healthy controls of matched age and gender were recruited through non-probability purposive sampling. Patients with diabetes mellitus, cerebrovascular accident, heart failure, bundle branch block, systemic arterial hypertension and ongoing antiarrhythmic therapy were excluded from the study. DMS 300-4L Holters were used to obtain ambulatory ECG recordings. Cardio Scan premier 12 lux software was used for analysis of T wave alternans. Results: Total one twenty subjects were enrolled in the study. Cardiomyopathic patients with positive T wave alternans were 13 (21.7 percent) out of 60, while only 4 (6.7 percent) out of 60 healthy controls demonstrated positive T wave alternans. There was significant variation in frequency of patients with positive T wave alternans as compared to healthy controls with p-value of 0.02. In cases the mean value of T wave alternans was 55.10 µv ± 33.58 while 39.45 µv ± 13.53 in controls. The difference in mean value of T wave alternans between cases and controls was significant with p-value of 0.001. Conclusion: The frequency of patients with cardiomyopathy having positive T wave alternans was significantly higher as compared to the healthy controls. (author)

  9. Adrenergic stimulation promotes T-wave alternans and arrhythmia inducibility in a TNF-alpha genetic mouse model of congestive heart failure.

    Science.gov (United States)

    Shusterman, Vladimir; McTiernan, Charles F; Goldberg, Anna; Saba, Samir; Salama, Guy; London, Barry

    2010-02-01

    T-wave alternans (TWA) is a proarrhythmic repolarization instability that is common in congestive heart failure (CHF). Although transgenic mice are commonly used to study the mechanisms of arrhythmogenesis in CHF, little is known about the dynamics of TWA in these species. We hypothesized that TWA is present in a TNF-alpha model of CHF and can be further promoted by adrenergic stimulation. We studied 16 TNF-alpha mice and 12 FVB controls using 1) in vivo intracardiac electrophysiological testing and 2) ambulatory telemetry during 30 min before and after an intraperitoneal injection of isoproterenol. TWA was examined using both linear and nonlinear filtering applied in the time domain. In addition, changes in the mean amplitude of the T wave and area under the T wave were computed. During intracardiac electrophysiological testing, none of the animals had TWA or inducible arrhythmias before the injection of isoproterenol. After the injection, sustained TWA and inducible ventricular tachyarrhythmias were observed in TNF-alpha mice but not in FVB mice. In ambulatory telemetry, before the isoproterenol injection, the cardiac cycle length (CL) was longer in TNF-alpha mice than in FVB mice (98 +/- 9 and 88 +/- 3 ms, P = 0.04). After the injection of isoproterenol, the CL became 8% and 6% shorter in TNF-alpha and FVB mice (P mice, the magnitude of TWA was 1.5-2 times greater than in FVB mice both before and after the isoproterenol injection. The magnitude of TWA increased significantly after the isoproterenol injection compared with the baseline in TNF-alpha mice (P = 0.003) but not in FVB mice. The mean amplitude of the T wave and area under the T wave increased 60% and 80% in FVB mice (P = 0.006 and 0.009) but not in TNF-alpha mice. In conclusion, TWA is present in a TNF-alpha model of CHF and can be further promoted by adrenergic stimulation, along with the enhanced susceptibility for ventricular arrhythmias.

  10. T-wave alternans: desempenho clínico, limitações, metodologias de análise T-wave alternans: desempeño clínico, limitaciones, metodologías de análisis T-wave alternans: clinical performance, limitations and analysis methodologies

    Directory of Open Access Journals (Sweden)

    Euler V. Garcia

    2011-03-01

    Full Text Available Reconhecer com precisão indivíduos com maior risco imediato de morte súbita cardíaca (MSC ainda é uma questão em aberto. A natureza fortuita dos eventos cardiovasculares agudos não parece se adequar ao conhecido modelo de indução de taquicardia/fibrilação ventricular por um gatilho em sincronia a um substrato arritmogênico estático. Quanto ao mecanismo da MSC, uma instabilidade elétrica dinâmica explicaria melhor a raridade da associação simultânea de um gatilho certo a um substrato cardíaco apropriado. Diversos estudos tentaram medir essa instabilidade elétrica cardíaca (ou um equivalente válido em uma sequência de batimentos cardíacos no ECG. Dentre os mecanismos possíveis podemos citar o prolongamento do QT, dispersão do QT, potenciais tardios, alternância de onda T ou T-wave alternans (TWA, e turbulência da frequência cardíaca. Este artigo se atém em particular ao papel da TWA no panorama atual da estratificação de risco cardíaco. Os achados sobre TWA ainda são heterogêneos, variando de um desempenho prognóstico muito bom até um quase nulo, dependendo da população clínica observada e protocolo clínico usado. Para preencher as atuais lacunas no conhecimento sobre TWA, profissionais médicos e pesquisadores devem explorar melhor as características técnicas das diversas tecnologias disponíveis para a avaliação de TWA e atentar ao fato de que os valores de TWA respondem a diversos outros fatores, além de medicamentos. Informações sobre mecanismos celulares e subcelulares da TWA estão fora do escopo deste artigo, mas são referenciados alguns dos principais trabalhos sobre este tópico, com o intuito de auxiliar no entendimento dos conceitos e fatos cobertos neste artigo.Reconocer con precisión individuos con mayor riesgo inmediato de muerte súbita cardíaca (MSC aun es una cuestión en abierto. La naturaleza fortuita de los eventos cardiovasculares agudos no parece adecuarse al conocido modelo

  11. Evaluation of T-wave alternans activity under stress conditions after 5 d and 21 d of sedentary head-down bed rest

    International Nuclear Information System (INIS)

    Martín-Yebra, A; Caiani, E G; Pellegrini, A; Monasterio, V; Laguna, P; Martínez, J P

    2015-01-01

    It is well known that prolonged microgravity leads to cardiovascular deconditioning, inducing significant changes in autonomic control of the cardiovascular system. This may adversely influence cardiac repolarization, and provoke cardiac rhythm disturbances. T-wave alternans (TWA), reflecting temporal and spatial repolarization heterogeneity, could be affected. The aim of this work was to test the hypothesis that 5 d and 21 d head-down (−6°) bed rest (HDBR) increases TWA, thus suggesting a higher underlying electrical instability and related arrhythmogenic risk.Forty-four healthy male volunteers were enrolled in the experiments as part of the European Space Agency’s HDBR studies. High-fidelity ECG was recorded during orthostatic tolerance (OT) and aerobic power (AP) tests, before (PRE) and after HDBR (POST). A multilead scheme for TWA amplitude estimation was used, where non-normalized and T-wave amplitude normalized TWA indices were computed. In addition, spectral analysis of heart rate variability during OT was assessed.Both 5 d and 21 d HDBR induced a reduction in orthostatic tolerance time (OTT), as well as a decrease in maximal oxygen uptake and reserve capacity, thus suggesting cardiovascular deconditioning. However, TWA indices were found not to increase. Interestingly, subjects with lower OTT after 5 d HDBR also showed higher TWA during recovery after OT testing, associated with unbalanced sympathovagal response, even before the HDBR. In contrast with previous observations, augmented ventricular heterogeneity related to 5 d and 21 d HDBR was not sufficient to increase TWA under stress conditions. (paper)

  12. Elevated T-wave alternans predicts nonsustained ventricular tachycardia in association with percutaneous coronary intervention in ST-segment elevation myocardial infarction (STEMI) patients.

    Science.gov (United States)

    Verrier, Richard L; Nearing, Bruce D; Ghanem, Raja N; Olson, Rachel E; Garberich, Ross F; Katsiyiannis, William T; Gornick, Charles C; Tang, Chuen Y; Henry, Timothy D

    2013-06-01

    Successful reperfusion with primary percutaneous coronary intervention (PCI) can paradoxically elicit temporary vulnerability to ventricular arrhythmia. We examined whether T-wave alternans (TWA) level is correlated with nonsustained ventricular tachycardia (NSVT) incidence in association with PCI in patients with acute ST-segment elevation myocardial infarction (STEMI). We analyzed continuous 24-hour ambulatory electrocardiograms in 48 STEMI patients during and after successful primary PCI, achieving Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow. TWA was measured using modified moving average method. Maximum TWA was elevated in patients with (N = 22) compared to without (N = 26) NSVT (75.1 ± 6.3 vs 49.9 ± 3.6 μV, P < 0.005) during the 22-hour monitoring period. TWA ≥ 60μV predicted NSVT with sensitivity of 77%; specificity, 73%; positive predictive value, 71%; and negative predictive value, 79%. Area under receiver operator characteristic curve (AUC) was 0.87 for maximum TWA in predicting NSVT. By comparison, ST-segment levels did not differ in patients with versus without NSVT and were not predictive (AUC = 0.52). TWA was elevated prior to PCI and remained elevated at 30 minutes after balloon inflation despite restoration of TIMI grade 3 flow in all patients, declining by 22 hours (P < 0.05). Maximum ST-segment levels decreased from before PCI to 30 minutes after balloon inflation. TWA is regionally specific, with higher values prior to PCI in precordial lead V5 than in V1 for left coronary lesions. TWA may be useful in identifying individuals at heightened risk for arrhythmia in association with primary PCI and can potentially signal time-dependent changes in arrhythmia vulnerability. © 2013 Wiley Periodicals, Inc.

  13. Effects of exercise rehabilitation on cardiac electrical instability assessed by T-wave alternans during ambulatory electrocardiogram monitoring in coronary artery disease patients without and with diabetes mellitus.

    Science.gov (United States)

    Kenttä, Tuomas; Tulppo, Mikko P; Nearing, Bruce D; Karjalainen, Jaana J; Hautala, Arto J; Kiviniemi, Antti M; Huikuri, Heikki V; Verrier, Richard L

    2014-09-15

    Effects of exercise rehabilitation on electrocardiographic markers of risk for sudden cardiac death have not been adequately studied. We examined effects of controlled exercise training on T-wave alternans (TWA) in 24-hour ambulatory electrocardiogram recordings in patients with stable coronary artery disease (CAD) without and with type 2 diabetes mellitus (DM). Consecutive patients with angiographically confirmed CAD were recruited to join the ARTEMIS (Innovation to Reduce Cardiovascular Complications of Diabetes at the Intersection) study. Exercise (n = 65) and control groups (n = 65) were matched on age, sex, DM, and previous myocardial infarction. Ambulatory electrocardiograms were recorded before and after a 2-year training period. TWA was assessed using time domain-modified moving average method by an investigator blinded to patients' clinical status. Average TWA values decreased in the rehabilitation group but not in control patients (rehabilitation [mean ± SEM]: 52.8 ± 1.7 μV vs 48.7 ± 1.5 μV, p exercise versus 10% (n = 2 of 20) of controls (p = 0.020). In CAD patients, 30% (n = 8 of 27) of positive TWA cases were converted with exercise versus 4% (n = 1 of 28) of controls (p = 0.012). In conclusion, this is the first report of the effectiveness of exercise rehabilitation to reduce TWA, a marker of sudden cardiac death risk, in patients with stable CAD. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Prognostic value of microvolt T-wave alternans in a real-world ICD population. Twente ICD Cohort Studie (TICS)

    NARCIS (Netherlands)

    Kraaier, K.; Olimulder, M. A. G. M.; van Dessel, P. F. H. M.; Wilde, A. A. M.; Scholten, M. F.

    2014-01-01

    Introduction Survival benefit from ICD implantation is relatively low in primary prevention patients. Better patient selection is important to maintain maximum survival benefit while reducing the number of unnecessary implants. Microvolt T-wave alternans (MTWA) is a promising risk marker. In this

  15. Utility of heart rate turbulence and T-Wave alternans to assess risk for Re-admission and cardiac death in hospitalized heart failure patients.

    Science.gov (United States)

    Yamada, Shinya; Yoshihisa, Akiomi; Sato, Yu; Sato, Takamasa; Kamioka, Masashi; Kaneshiro, Takashi; Oikawa, Masayoshi; Kobayashi, Atsushi; Suzuki, Hitoshi; Ishida, Takafumi; Takeishi, Yasuchika

    2018-05-18

    Heart failure (HF) patients have a higher risk of recurrent HF and cardiac death, and electrical remodeling is considered to be an important factor for HF progression. The present study aimed to validate the utility of electrocardiogram and Holter monitoring for the risk stratification of HF patients. Our study comprised 215 patients (144 males, mean age 62 years) who had been hospitalized due to acute decompensated HF. Electrocardiogram (QRS duration and QTc interval) and 24-hour Holter monitoring (heart rate variability, heart rate turbulence and T-wave alternans [TWA]) were performed in stable condition before discharge. The clinical characteristics and outcomes were then investigated. During a median follow-up period of 2.7 years, there were 83 (38.6%) cardiac events (re-hospitalization due to worsening HF [n = 51] or cardiac death [n = 32]). The patients with cardiac events had a lower turbulence slope (TS) and higher TWA compared to those without cardiac events (TS, 3.0±5.5 ms/RR vs. 5.3±5.6 ms/RR, P = 0.001; TWA, 66.1±19.6 μV vs. 54.7±15.1 μV, P < 0.001). Univariable analysis showed that TS, TWA, QRS duration, and QTc interval were associated with cardiac events (P = 0.004, P < 0.001, P = 0.037 and P = 0.024, respectively), while the multivariable analysis after the adjustment of multiple confounders showed that TS and TWA were independent predictive factors of cardiac events with a hazard ratio of 0.936 and 1.015 (95% confidence interval [CI]: 0.860-0.974, P = 0.006; and 95% CI: 1.003-1.027, p = 0.016), respectively. The measurement of TS and TWA is useful for assessing risk for re-hospitalization and cardiac death in HF patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  16. Use of T-wave alternans in identifying patients with coronary artery disease.

    Science.gov (United States)

    Figliozzi, Stefano; Stazi, Alessandra; Pinnacchio, Gaetano; Laurito, Marianna; Parrinello, Rossella; Villano, Angelo; Russo, Giulio; Milo, Maria; Mollo, Roberto; Lanza, Gaetano A; Crea, Filippo

    2016-01-01

    Microvolt T-wave alternans (MTWA) has been found to predict fatal events in patients with coronary artery disease (CAD). In a previous study, we found that MTWA values are higher in patients with CAD, compared with apparently healthy individuals. In this study, we assessed the relation between CAD and MTWA in patients with a diagnosis based on coronary angiography results. We studied 98 consecutive patients undergoing coronary angiography for suspected CAD. All patients underwent a maximal exercise stress test (EST), and MTWA was measured in the precordial ECG leads. Patients were divided into three groups: 40 patients without any significant (>50%) stenosis (group 1); 47 patients with significant stenosis (group 2); and 11 patients with a previous percutaneous coronary intervention (PCI) who had no evidence of restenosis (group 3). EST was repeated after 1 month in 24 group 2 patients who underwent PCI and in 17 group 1 patients. MTWA was significantly higher in group 2 (58.7 ± 24 μV) compared with group 1 (34.2  ± 15 μV, P < 0.01) and group 3 (43.2 ± 24 μV, P < 0.05). An MTWA greater than 60 μV had 95% specificity and 82% positive predictive value for obstructive CAD. At 1-month follow-up, MTWA decreased significantly in patients treated with PCI (from 61.3 ± 22 to 43.5 ± 17 μV; P < 0.001), but not in group 1 patients (from 50.5 ± 22 to 44.3 ± 19 μV, P = 0.19). MTWA is increased in patients with obstructive CAD and is reduced by coronary revascularization. An assessment of MTWA can be helpful in identifying which patients with suspected CAD are likely to show obstructive CAD on angiography.

  17. Microvolt T-wave alternans and autonomic nervous system parameters can be helpful in the identification of low-arrhythmic risk patients with ischemic left ventricular systolic dysfunction.

    Science.gov (United States)

    Daniłowicz-Szymanowicz, Ludmiła; Kaufmann, Damian; Rozwadowska, Katarzyna; Kempa, Maciej; Lewicka, Ewa; Raczak, Grzegorz

    2018-01-01

    The role of implantable cardioverter-defibrillator (ICD) placement in the primary prevention of sudden cardiac death (SCD) in all consecutive patients with left ventricular ejection fraction (LVEF) ≤ 35% is still a matter of hot debate due to the fact that the population of these patients is highly heterogeneous in terms of the SCD risk. Nevertheless, reduced LVEF is still the only established criterion during qualification of patients for ICD implantation in the primary prevention of SCD, therefore identification of persons with particularly high risk among patients with LVEF ≤35% is currently of lesser importance. More important seems to be the selection of individuals with relatively low risk of SCD in whom ICD implantation can be safely postponed. The aim of the study was to determine whether well-known, non-invasive parameters, such as microvolt T-wave alternans (MTWA), baroreflex sensitivity (BRS) and short-term heart rate variability (HRV), can be helpful in the identification of low-arrhythmic risk patients with ischemic left ventricular systolic dysfunction. In 141 patients with coronary artery disease and LVEF ≤ 35%, MTWA testing, as well as BRS and short-term HRV parameters, were analysed. During 34 ± 13 months of follow-up 37 patients had arrhythmic episode (EVENT): SCD, non-fatal sustained ventricular arrhythmia (ventricular tachycardia [VT] or ventricular fibrillation [VF]), or adequate high-voltage ICD intervention (shock) due to a rapid ventricular arrhythmia ≥200/min. LVEF, non-negative MTWA (MTWA_non-neg), BRS and low frequency power in normalized units (LFnu) turned out to be associated with the incidence of EVENT in univariate Cox analysis. The cut-off values for BRS and LFnu that most accurately distinguished between patients with and without EVENT were 3 ms/mmHg and 23, respectively. The only variable that provided 100% negative predictive value (NPV) for EVENT was negative MTWA result (MTWA_neg), but solely for initial 12 months of

  18. An Excel-based implementation of the spectral method of action potential alternans analysis.

    Science.gov (United States)

    Pearman, Charles M

    2014-12-01

    Action potential (AP) alternans has been well established as a mechanism of arrhythmogenesis and sudden cardiac death. Proper interpretation of AP alternans requires a robust method of alternans quantification. Traditional methods of alternans analysis neglect higher order periodicities that may have greater pro-arrhythmic potential than classical 2:1 alternans. The spectral method of alternans analysis, already widely used in the related study of microvolt T-wave alternans, has also been used to study AP alternans. Software to meet the specific needs of AP alternans analysis is not currently available in the public domain. An AP analysis tool is implemented here, written in Visual Basic for Applications and using Microsoft Excel as a shell. This performs a sophisticated analysis of alternans behavior allowing reliable distinction of alternans from random fluctuations, quantification of alternans magnitude, and identification of which phases of the AP are most affected. In addition, the spectral method has been adapted to allow detection and quantification of higher order regular oscillations. Analysis of action potential morphology is also performed. A simple user interface enables easy import, analysis, and export of collated results. © 2014 The Author. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  19. Application of a New Robust ECG T-Wave Delineation Algorithm for the Evaluation of the Autonomic Innervation of the Myocardium

    DEFF Research Database (Denmark)

    Cesari, Matteo; Mehlsen, Jesper; Mehlsen, Anne-Birgitte

    2016-01-01

    T-wave amplitude (TWA) is a well know index of the autonomic innervation of the myocardium. However, until now it has been evaluated only manually or with simple and inefficient algorithms. In this paper, we developed a new robust single-lead electrocardiogram (ECG) T-wave delineation algorithm...

  20. The TWA 3 Young Triple System: Orbits, Disks, Evolution

    Energy Technology Data Exchange (ETDEWEB)

    Kellogg, Kendra [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada); Prato, L.; Avilez, I.; Wasserman, L. H.; Levine, S. E.; Bosh, A. S. [Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States); Torres, Guillermo [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Schaefer, G. H. [The CHARA Array of Georgia State University, Mount Wilson Observatory, Mount Wilson, CA 91023 (United States); Ruíz-Rodríguez, D. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Bonanos, Alceste Z. [IAASARS, National Observatory of Athens, 15236 Penteli (Greece); Guenther, E. W. [Thüringer Landessternwarte Tautenburg, D-07778 Tautenburg (Germany); Neuhäuser, R. [Astrophysikalisches Institut und Universitäts-Sternwarte, FSU Jena, Schillergäßchen 2-3, D-07745 Jena (Germany); Morzinski, Katie M.; Close, Laird; Hinz, Phil; Males, Jared R. [Steward Observatory, University of Arizona, 933 N. Cherry Ave, Tucson, AZ 85721 (United States); Bailey, Vanessa, E-mail: kkellogg@uwo.ca, E-mail: lprato@lowell.edu [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA, 94305 (United States)

    2017-08-01

    We have characterized the spectroscopic orbit of the TWA 3A binary and provide preliminary families of probable solutions for the TWA 3A visual orbit, as well as for the wide TWA 3A–B orbit. TWA 3 is a hierarchical triple located at 34 pc in the ∼10 Myr old TW Hya association. The wide component separation is 1.″55; the close pair was first identified as a possible binary almost 20 years ago. We initially identified the 35-day period orbital solution using high-resolution infrared spectroscopy that angularly resolved the A and B components. We then refined the preliminary orbit by combining the infrared data with a reanalysis of our high-resolution optical spectroscopy. The orbital period from the combined spectroscopic solution is ∼35 days, the eccentricity is ∼0.63, and the mass ratio is ∼0.84; although this high mass ratio would suggest that optical spectroscopy alone should be sufficient to identify the orbital solution, the presence of the tertiary B component likely introduced confusion in the blended optical spectra. Using millimeter imaging from the literature, we also estimate the inclinations of the stellar orbital planes with respect to the TWA 3A circumbinary disk inclination and find that all three planes are likely misaligned by at least ∼30°. The TWA 3A spectroscopic binary components have spectral types of M4.0 and M4.5; TWA 3B is an M3. We speculate that the system formed as a triple, is bound, and that its properties were shaped by dynamical interactions between the inclined orbits and disk.

  1. THE COOLEST ISOLATED BROWN DWARF CANDIDATE MEMBER OF TWA

    Energy Technology Data Exchange (ETDEWEB)

    Gagné, Jonathan; Lafrenière, David; Doyon, René; Malo, Lison; Artigau, Étienne [Département de Physique and Observatoire du Mont-Mégantic, Université de Montréal, C.P. 6128 Succ. Centre-ville, Montréal, Qc H3C 3J7 (Canada); Faherty, Jacqueline K. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015 (United States); Cruz, Kelle, E-mail: jonathan.gagne@astro.umontreal.ca, E-mail: jfaherty17@gmail.com [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10034 (United States)

    2014-04-10

    We present two new late-type brown dwarf candidate members of the TW Hydrae association (TWA): 2MASS J12074836-3900043 and 2MASS J12474428-3816464, which were found as part of the BANYAN all-sky survey (BASS) for brown dwarf members of nearby young associations. We obtained near-infrared (NIR) spectroscopy for both objects (NIR spectral types are respectively L1 and M9), as well as optical spectroscopy for J1207-3900 (optical spectral type is L0γ), and show that both display clear signs of low gravity, and thus youth. We use the BANYAN II Bayesian inference tool to show that both objects are candidate members to TWA with a very low probability of being field contaminants, although the kinematics of J1247-3816 seem slightly at odds with that of other TWA members. J1207-3900 is currently the latest-type and the only isolated L-type candidate member of TWA. Measuring the distance and radial velocity of both objects is still required to claim them as bona fide members. Such late-type objects are predicted to have masses down to 11-15 M {sub Jup} at the age of TWA, which makes them compelling targets to study atmospheric properties in a regime similar to that of currently known imaged extrasolar planets.

  2. ELF Magnetic Fields, Transients and TWA Metrics (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    Kavet, R

    1999-07-01

    Residential measurements of ambient power frequency magnetic fields may serve as surrogates for personal exposures. There are few data available, however, to determine how far back in time this surrogacy holds. A limited amount of research on residential transients suggests that, all other factors being equivalent, larger transients may propagate within VHCC neighbourhoods than within LCC neighbourhoods. However, the presence of a conductive residential ground pathway also appears to be a potentially important factor associated with residential transient activity. The use of the TWA metric was prompted by the need for an exposure score simple enough to summarise an individual's exposure over a prior interval, yet specific to the agent of concern, namely the power frequency magnetic field. To the extent that the TWA exposure is associated with health outcomes in the absence of bias, including confounding, the TWA metric is important. (author)

  3. ELF Magnetic Fields, Transients and TWA Metrics (invited paper)

    International Nuclear Information System (INIS)

    Kavet, R.

    1999-01-01

    Residential measurements of ambient power frequency magnetic fields may serve as surrogates for personal exposures. There are few data available, however, to determine how far back in time this surrogacy holds. A limited amount of research on residential transients suggests that, all other factors being equivalent, larger transients may propagate within VHCC neighbourhoods than within LCC neighbourhoods. However, the presence of a conductive residential ground pathway also appears to be a potentially important factor associated with residential transient activity. The use of the TWA metric was prompted by the need for an exposure score simple enough to summarise an individual's exposure over a prior interval, yet specific to the agent of concern, namely the power frequency magnetic field. To the extent that the TWA exposure is associated with health outcomes in the absence of bias, including confounding, the TWA metric is important. (author)

  4. Pulsed Accretion in the T Tauri Binary TWA 3A

    Energy Technology Data Exchange (ETDEWEB)

    Tofflemire, Benjamin M.; Mathieu, Robert D. [Department of Astronomy, University of Wisconsin–Madison, 475 North Charter Street, Madison, WI 53706 (United States); Herczeg, Gregory J. [The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Akeson, Rachel L.; Ciardi, David R. [NASA Exoplanet Science Institute, IPAC/Caltech, Pasadena, CA 91125 (United States)

    2017-06-20

    TWA 3A is the most recent addition to a small group of young binary systems that both actively accrete from a circumbinary disk and have spectroscopic orbital solutions. As such, it provides a unique opportunity to test binary accretion theory in a well-constrained setting. To examine TWA 3A’s time-variable accretion behavior, we have conducted a two-year, optical photometric monitoring campaign, obtaining dense orbital phase coverage (∼20 observations per orbit) for ∼15 orbital periods. From U -band measurements we derive the time-dependent binary mass accretion rate, finding bursts of accretion near each periastron passage. On average, these enhanced accretion events evolve over orbital phases 0.85 to 1.05, reaching their peak at periastron. The specific accretion rate increases above the quiescent value by a factor of ∼4 on average but the peak can be as high as an order of magnitude in a given orbit. The phase dependence and amplitude of TWA 3A accretion is in good agreement with numerical simulations of binary accretion with similar orbital parameters. In these simulations, periastron accretion bursts are fueled by periodic streams of material from the circumbinary disk that are driven by the binary orbit. We find that TWA 3A’s average accretion behavior is remarkably similar to DQ Tau, another T Tauri binary with similar orbital parameters, but with significantly less variability from orbit to orbit. This is only the second clear case of orbital-phase-dependent accretion in a T Tauri binary.

  5. The role of mitochondria for the regulation of cardiac alternans

    Directory of Open Access Journals (Sweden)

    Stela M Florea

    2010-11-01

    Full Text Available Electromechanical and Ca alternans is a beat-to-beat alternation of action potential duration, contraction strength and Ca transient amplitude observed in cardiac myocytes at regular stimulation frequency. Ca alternans is a multifactorial process that is causally linked to cardiac arrhythmias. At the cellular level, conditions that increase fractional release from the sarcoplasmic reticulum or reduce diastolic Ca sequestration favor the occurrence of alternans. Mitochondria play a significant role in cardiac excitation-contraction coupling and Ca signaling by providing the energy for contraction and ATP-dependent processes and possibly by serving as Ca buffering organelles. Here we tested the hypothesis that impairment of mitochondrial function generates conditions that favor the occurrence of Ca alternans. Alternans were elicited by electrical pacing (>1 Hz in single cat atrial myocytes and intracellular Ca ([Ca]i was measured with the fluorescent Ca indicator Indo-1. The degree of alternans was quantified as the alternans ratio (AR=1-S/L, where S/L is the ratio of the small to the large amplitude of a pair of alternating Ca transients. Dissipation of mitochondrial membrane potential (with FCCP as well as inhibition of mitochondrial F1/F0-ATP synthase (oligomycin, electrontransport chain (rotenone, antimycin, CN-, Ca-dependent dehydrogenases and mitochondrial Ca uptake or extrusion, all enhanced AR and lowered the threshold for the occurrence of Ca alternans. The data indicate that impairment of mitochondrial function adversely affects cardiac Ca cycling leading to proarrhythmic Ca alternans.

  6. Mechanical perturbation control of cardiac alternans

    Science.gov (United States)

    Hazim, Azzam; Belhamadia, Youssef; Dubljevic, Stevan

    2018-05-01

    Cardiac alternans is a disturbance in heart rhythm that is linked to the onset of lethal cardiac arrhythmias. Mechanical perturbation control has been recently used to suppress alternans in cardiac tissue of relevant size. In this control strategy, cardiac tissue mechanics are perturbed via active tension generated by the heart's electrical activity, which alters the tissue's electric wave profile through mechanoelectric coupling. We analyze the effects of mechanical perturbation on the dynamics of a map model that couples the membrane voltage and active tension systems at the cellular level. Therefore, a two-dimensional iterative map of the heart beat-to-beat dynamics is introduced, and a stability analysis of the system of coupled maps is performed in the presence of a mechanical perturbation algorithm. To this end, a bidirectional coupling between the membrane voltage and active tension systems in a single cardiac cell is provided, and a discrete form of the proposed control algorithm, that can be incorporated in the coupled maps, is derived. In addition, a realistic electromechanical model of cardiac tissue is employed to explore the feasibility of suppressing alternans at cellular and tissue levels. Electrical activity is represented in two detailed ionic models, the Luo-Rudy 1 and the Fox models, while two active contractile tension models, namely a smooth variant of the Nash-Panfilov model and the Niederer-Hunter-Smith model, are used to represent mechanical activity in the heart. The Mooney-Rivlin passive elasticity model is employed to describe passive mechanical behavior of the myocardium.

  7. Alternans promotion in cardiac electrophysiology models by delay differential equations.

    Science.gov (United States)

    Gomes, Johnny M; Dos Santos, Rodrigo Weber; Cherry, Elizabeth M

    2017-09-01

    Cardiac electrical alternans is a state of alternation between long and short action potentials and is frequently associated with harmful cardiac conditions. Different dynamic mechanisms can give rise to alternans; however, many cardiac models based on ordinary differential equations are not able to reproduce this phenomenon. A previous study showed that alternans can be induced by the introduction of delay differential equations (DDEs) in the formulations of the ion channel gating variables of a canine myocyte model. The present work demonstrates that this technique is not model-specific by successfully promoting alternans using DDEs for five cardiac electrophysiology models that describe different types of myocytes, with varying degrees of complexity. By analyzing results across the different models, we observe two potential requirements for alternans promotion via DDEs for ionic gates: (i) the gate must have a significant influence on the action potential duration and (ii) a delay must significantly impair the gate's recovery between consecutive action potentials.

  8. Alternans promotion in cardiac electrophysiology models by delay differential equations

    Science.gov (United States)

    Gomes, Johnny M.; dos Santos, Rodrigo Weber; Cherry, Elizabeth M.

    2017-09-01

    Cardiac electrical alternans is a state of alternation between long and short action potentials and is frequently associated with harmful cardiac conditions. Different dynamic mechanisms can give rise to alternans; however, many cardiac models based on ordinary differential equations are not able to reproduce this phenomenon. A previous study showed that alternans can be induced by the introduction of delay differential equations (DDEs) in the formulations of the ion channel gating variables of a canine myocyte model. The present work demonstrates that this technique is not model-specific by successfully promoting alternans using DDEs for five cardiac electrophysiology models that describe different types of myocytes, with varying degrees of complexity. By analyzing results across the different models, we observe two potential requirements for alternans promotion via DDEs for ionic gates: (i) the gate must have a significant influence on the action potential duration and (ii) a delay must significantly impair the gate's recovery between consecutive action potentials.

  9. Optimization of Alternan production by newly isolated leuconostoc mesenteroides

    International Nuclear Information System (INIS)

    Raafat, E.I.; Bashandy, A.S.; Gamal, R.F; Abdelhady, H.M.; Nasr, S.A

    2010-01-01

    Seven isolates out out of 75 Alternan producing bacterial isolates were selected for their highly efficacy, they identified as leuconostoc mesenteriodes. Two local strains in addition to L. mesenteriodes NRRL B-1355 were tested for Alternan production using shake flasks and bioreactor as batch cultures, they gave the high Alternan production on modified Raemackers and Vandamme medium containing 120 gL -1 sucrose incubated at 30 degree C for for 22 hrs in shake flasks at 200 rpm . Whereas the highest yield of dextran was attained in static cultures. L. mesenteriodes M m6 and L. mesenteriodes C m6 were obtained after exposing the parent strains to gamma radiation dose of 3.0 KGy, which led to increase the Alternan and dextran productivity about 1.93 and 1.82 fold. The agitation rate at 300 rpm using batch bioreactor technique was the best treatment for Alternan production by L. mesenteriodes M m6 , the Alternan yield and productivity was increased by about 11.21 % and 204 %, respectively as compared with that produced in batch shake flasks at 200 rpm.

  10. An Excel‐based implementation of the spectral method of action potential alternans analysis

    Science.gov (United States)

    Pearman, Charles M.

    2014-01-01

    Abstract Action potential (AP) alternans has been well established as a mechanism of arrhythmogenesis and sudden cardiac death. Proper interpretation of AP alternans requires a robust method of alternans quantification. Traditional methods of alternans analysis neglect higher order periodicities that may have greater pro‐arrhythmic potential than classical 2:1 alternans. The spectral method of alternans analysis, already widely used in the related study of microvolt T‐wave alternans, has also been used to study AP alternans. Software to meet the specific needs of AP alternans analysis is not currently available in the public domain. An AP analysis tool is implemented here, written in Visual Basic for Applications and using Microsoft Excel as a shell. This performs a sophisticated analysis of alternans behavior allowing reliable distinction of alternans from random fluctuations, quantification of alternans magnitude, and identification of which phases of the AP are most affected. In addition, the spectral method has been adapted to allow detection and quantification of higher order regular oscillations. Analysis of action potential morphology is also performed. A simple user interface enables easy import, analysis, and export of collated results. PMID:25501439

  11. Fast T Wave Detection Calibrated by Clinical Knowledge with Annotation of P and T Waves

    Directory of Open Access Journals (Sweden)

    Mohamed Elgendi

    2015-07-01

    Full Text Available Background: There are limited studies on the automatic detection of T waves in arrhythmic electrocardiogram (ECG signals. This is perhaps because there is no available arrhythmia dataset with annotated T waves. There is a growing need to develop numerically-efficient algorithms that can accommodate the new trend of battery-driven ECG devices. Moreover, there is also a need to analyze long-term recorded signals in a reliable and time-efficient manner, therefore improving the diagnostic ability of mobile devices and point-of-care technologies. Methods: Here, the T wave annotation of the well-known MIT-BIH arrhythmia database is discussed and provided. Moreover, a simple fast method for detecting T waves is introduced. A typical T wave detection method has been reduced to a basic approach consisting of two moving averages and dynamic thresholds. The dynamic thresholds were calibrated using four clinically known types of sinus node response to atrial premature depolarization (compensation, reset, interpolation, and reentry. Results: The determination of T wave peaks is performed and the proposed algorithm is evaluated on two well-known databases, the QT and MIT-BIH Arrhythmia databases. The detector obtained a sensitivity of 97.14% and a positive predictivity of 99.29% over the first lead of the validation databases (total of 221,186 beats. Conclusions: We present a simple yet very reliable T wave detection algorithm that can be potentially implemented on mobile battery-driven devices. In contrast to complex methods, it can be easily implemented in a digital filter design.

  12. Using delay differential equations to induce alternans in a model of cardiac electrophysiology.

    Science.gov (United States)

    Eastman, Justin; Sass, Julian; Gomes, Johnny M; Dos Santos, Rodrigo Weber; Cherry, Elizabeth M

    2016-09-07

    Cardiac electrical alternans is a period-2 dynamical behavior with alternating long and short action potential durations (APD) that often precedes dangerous arrhythmias associated with cardiac arrest. Despite the importance of alternans, many current ordinary differential equations models of cardiac electrophysiology do not produce alternans, thereby limiting the use of these models for studying the mechanisms that underlie this condition. Because delay differential equations (DDEs) commonly induce complex dynamics in other biological systems, we investigate whether incorporating DDEs can lead to alternans development in cardiac models by studying the Fox et al. canine ventricular action potential model. After suppressing the alternans in the original model, we show that alternans can be obtained by introducing DDEs in the model gating variables, and we quantitatively compare the DDE-induced alternans with the alternans present in the original model. We analyze the behavior of the voltage, currents, and gating variables of the model to study the effects of the delays and to determine how alternans develops in that setting, and we discuss the mathematical and physiological implications of our findings. In future work, we aim to apply our approach to induce alternans in models that do not naturally exhibit such dynamics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Physiology and analysis of the electrocardiographic T wave in mice

    DEFF Research Database (Denmark)

    Speerschneider, T; Thomsen, Morten Bækgaard

    2013-01-01

    The murine electrocardiogram (ECG) is a valuable tool in cardiac research, although the definition of the T wave has been a matter of debate for several years potentially leading to incomparable data. By this study, we seek to make a clear definition of the murine T wave. Moreover, we investigate...... the consequences of performing QT interval correction in anaesthetized mice....

  14. Generation Mechanism of Alternans in Luo-Rudy Model

    Science.gov (United States)

    Kitajima, Hiroyuki; Ioka, Eri; Yazawa, Toru

    Electrical alternans is the alternating amplitude from beat to beat in the action potential of the cardiac cell. It has been associated with ventricular arrhythmias in many clinical studies; however, its dynamical mechanisms remain unknown. The reason is that we do not have realistic network models of the heart system. Recently, Yazawa clarified the network structure of the heart and the central nerve system in the crustacean heart. In this study, we construct a simple model of the heart system based on Yazawa’s experimental data. Using this model, we clarify that two parameters (the conductance of sodium ions and free concentration of potassium ions in the extracellular compartment) play the key roles of generating alternans. In particular, we clarify that the inactivation gate of the time-independent potassium channel is the most important parameter. Moreover, interaction between the membrane potential and potassium ionic currents is significant for generating alternate rhythms. This result indicates that if the muscle cell has problems such as channelopathies, there is great risk of generating alternans.

  15. Sympathetic Nervous Regulation of Calcium and Action Potential Alternans in the Intact Heart.

    Science.gov (United States)

    Winter, James; Bishop, Martin J; Wilder, Catherine D E; O'Shea, Christopher; Pavlovic, Davor; Shattock, Michael J

    2018-01-01

    Rationale: Arrhythmogenic cardiac alternans are thought to be an important determinant for the initiation of ventricular fibrillation. There is limited information on the effects of sympathetic nerve stimulation (SNS) on alternans in the intact heart and the conclusions of existing studies, focused on investigating electrical alternans, are conflicted. Meanwhile, several lines of evidence implicate instabilities in Ca handling, not electrical restitution, as the primary mechanism underpinning alternans. Despite this, there have been no studies on Ca alternans and SNS in the intact heart. The present study sought to address this, by application of voltage and Ca optical mapping for the simultaneous study of APD and Ca alternans in the intact guinea pig heart during direct SNS. Objective : To determine the effects of SNS on APD and Ca alternans in the intact guinea pig heart and to examine the mechanism(s) by which the effects of SNS are mediated. Methods and Results : Studies utilized simultaneous voltage and Ca optical mapping in isolated guinea pig hearts with intact innervation. Alternans were induced using a rapid dynamic pacing protocol. SNS was associated with rate-independent shortening of action potential duration (APD) and the suppression of APD and Ca alternans, as indicated by a shift in the alternans threshold to faster pacing rates. Qualitatively similar results were observed with exogenous noradrenaline perfusion. In contrast with previous reports, both SNS and noradrenaline acted to flatten the slope of the electrical restitution curve. Pharmacological block of the slow delayed rectifying potassium current (I Ks ), sufficient to abolish I Ks -mediated APD-adaptation, partially reversed the effects of SNS on pacing-induced alternans. Treatment with cyclopiazonic acid, an inhibitor of the sarco(endo)plasmic reticulum ATPase, had opposite effects to that of SNS, acting to increase susceptibility to alternans, and suggesting that accelerated Ca reuptake

  16. β-Adrenergic receptor stimulation inhibits proarrhythmic alternans in postinfarction border zone cardiomyocytes: a computational analysis.

    Science.gov (United States)

    Tomek, Jakub; Rodriguez, Blanca; Bub, Gil; Heijman, Jordi

    2017-08-01

    The border zone (BZ) of the viable myocardium adjacent to an infarct undergoes extensive autonomic and electrical remodeling and is prone to repolarization alternans-induced cardiac arrhythmias. BZ remodeling processes may promote or inhibit Ca 2+ and/or repolarization alternans and may differentially affect ventricular arrhythmogenesis. Here, we used a detailed computational model of the canine ventricular cardiomyocyte to study the determinants of alternans in the BZ and their regulation by β-adrenergic receptor (β-AR) stimulation. The BZ model developed Ca 2+ transient alternans at slower pacing cycle lengths than the control model, suggesting that the BZ may promote spatially heterogeneous alternans formation in an infarcted heart. β-AR stimulation abolished alternans. By evaluating all combinations of downstream β-AR stimulation targets, we identified both direct (via ryanodine receptor channels) and indirect [via sarcoplasmic reticulum (SR) Ca 2+ load] modulation of SR Ca 2+ release as critical determinants of Ca 2+ transient alternans. These findings were confirmed in a human ventricular cardiomyocyte model. Cell-to-cell coupling indirectly modulated the likelihood of alternans by affecting the action potential upstroke, reducing the trigger for SR Ca 2+ release in one-dimensional strand simulations. However, β-AR stimulation inhibited alternans in both single and multicellular simulations. Taken together, these data highlight a potential antiarrhythmic role of sympathetic hyperinnervation in the BZ by reducing the likelihood of alternans and provide new insights into the underlying mechanisms controlling Ca 2+ transient and repolarization alternans. NEW & NOTEWORTHY We integrated, for the first time, postmyocardial infarction electrical and autonomic remodeling in a detailed, validated computer model of β-adrenergic stimulation in ventricular cardiomyocytes. Here, we show that β-adrenergic stimulation inhibits alternans and provide novel insights

  17. Characterizing Spatial Dynamics of Bifurcation to Alternans in Isolated Whole Rabbit Hearts Based on Alternate Pacing

    Directory of Open Access Journals (Sweden)

    Kanchan Kulkarni

    2015-01-01

    Full Text Available Sudden cardiac death instigated by ventricular fibrillation (VF is the largest cause of natural death in the USA. Alternans, a beat-to-beat alternation in the action potential duration, has been implicated as being proarrhythmic. The onset of alternans is mediated via a bifurcation, which may occur through either a smooth or a border-collision mechanism. The objective of this study was to characterize the mechanism of bifurcation to alternans based on experiments in isolated whole rabbit hearts. High resolution optical mapping was performed and the electrical activity was recorded from the left ventricle (LV epicardial surface of the heart. Each heart was paced using an “alternate pacing protocol,” where the basic cycle length (BCL was alternatively perturbed by ±δ. Local onset of alternans in the heart, BCLstart, was measured in the absence of perturbations (δ=0 and was defined as the BCL at which 10% of LV exhibited alternans. The influences of perturbation size were investigated at two BCLs: one prior to BCLstart (BCLprior=BCLstart+20 ms and one preceding BCLprior (BCLfar=BCLstart+40 ms. Our results demonstrate significant spatial correlation of the region exhibiting alternans with smooth bifurcation characteristics, indicating that transition to alternans in isolated rabbit hearts occurs predominantly through smooth bifurcation.

  18. T-tubule disruption promotes calcium alternans in failing ventricular myocytes: mechanistic insights from computational modeling.

    Science.gov (United States)

    Nivala, Michael; Song, Zhen; Weiss, James N; Qu, Zhilin

    2015-02-01

    In heart failure (HF), T-tubule (TT) disruption contributes to dyssynchronous calcium (Ca) release and impaired contraction, but its role in arrhythmogenesis remains unclear. In this study, we investigate the effects of TT disruption and other HF remodeling factors on Ca alternans in ventricular myocytes using computer modeling. A ventricular myocyte model with detailed spatiotemporal Ca cycling modeled by a coupled Ca release unit (CRU) network was used, in which the L-type Ca channels and the ryanodine receptor (RyR) channels were simulated by random Markov transitions. TT disruption, which removes the L-type Ca channels from the associated CRUs, results in "orphaned" RyR clusters and thus provides increased opportunity for spark-induced Ca sparks to occur. This effect combined with other HF remodeling factors promoted alternans by two distinct mechanisms: 1) for normal sarco-endoplasmic reticulum Ca ATPase (SERCA) activity, alternans was caused by both CRU refractoriness and coupling. The increased opportunity for spark-induced sparks by TT disruption combined with the enhanced CRU coupling by Ca elevation in the presence or absence of increased RyR leakiness facilitated spark synchronization on alternate beats to promote Ca alternans; 2) for down-regulated SERCA, alternans was caused by the sarcoplasmic reticulum (SR) Ca load-dependent mechanism, independent of CRU refractoriness. TT disruption and increased RyR leakiness shifted and steepened the SR Ca release-load relationship, which combines with down-regulated SERCA to promote Ca alternans. In conclusion, the mechanisms of Ca alternans for normal and down-regulated SERCA are different, and TT disruption promotes Ca alternans by both mechanisms, which may contribute to alternans at different stages of HF. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. T-wave morphology analysis of competitive athletes

    DEFF Research Database (Denmark)

    Hong, L; Andersen, Lars Juel; Graff, Claus

    2015-01-01

    BACKGROUND: T-wave morphology has been shown to be more sensitive than QT and QTc interval to describe repolarization abnormalities. The electrocardiogram (ECG) performed in athletes may manifest abnormalities, including repolarization alterations. The aim of this study was to investigate...... the characteristics of T-wave morphology features in athletes. METHODS: Eighty male elite athletes, consisting of 40 Tour de France cyclists (age 27±5years), 40 soccer players (age 26±6years) and 40 healthy men (age 27±5years) were included. RESULTS: Sinus bradycardia, left ventricular (LV) hypertrophy, incomplete...... interval, and repolarization features than the control group. CONCLUSIONS: T-wave morphology of athletes is different from non-athletes, depending of the sport. Decreased potassium current in cardiomyocytes associated with LVH may contribute to these changes....

  20. ROMANO-WARD SYNDROME ASSOCIATED WITH TU ELECTRICAL ALTERNANS

    Directory of Open Access Journals (Sweden)

    DJAWAN

    1981-05-01

    Full Text Available A case o f the electrical alternans of t he TU wave and peri odic nega t ive U wave associated with c l ini cal symptoms , e lectrocardi ographic a nd postmortem findi ng s o f Romano- Ward Syndrome has been pres ented. No e lec ~ r o l y te d ist urbance was found t o be r esponsible for t his exceptional l y rare situation . Changes i n A-V conduct i on and left bu n• d Ie branch block could be a t tributed to the d i f f use c or onary s clero sis and s ubs equent i schemia in the myocardial c onduction t.issues . The e lectrical alternans of t he U wave or TU complex of the e lectrocardiogram i s an exceeding ly r are s i t uation without any clearly known mechanism for i ts appea rance . A case of thi s phenome no~ i n as soc iation with RomanoWard Syndrome has been presented whe rein an abnorma l ity i n A-V conduction and left bund le branch block cou ld be encountered .

  1. Earthquake Source Parameters Inferred from T-Wave Observations

    Science.gov (United States)

    Perrot, J.; Dziak, R.; Lau, T. A.; Matsumoto, H.; Goslin, J.

    2004-12-01

    The seismicity of the North Atlantic Ocean has been recorded by two networks of autonomous hydrophones moored within the SOFAR channel on the flanks of the Mid-Atlantic Ridge (MAR). In February 1999, a consortium of U.S. investigators (NSF and NOAA) deployed a 6-element hydrophone array for long-term monitoring of MAR seismicity between 15o-35oN south of the Azores. In May 2002, an international collaboration of French, Portuguese, and U.S. researchers deployed a 6-element hydrophone array north of the Azores Plateau from 40o-50oN. The northern network (referred to as SIRENA) was recovered in September 2003. The low attenuation properties of the SOFAR channel for earthquake T-wave propagation results in a detection threshold reduction from a magnitude completeness level (Mc) of ˜ 4.7 for MAR events recorded by the land-based seismic networks to Mc=3.0 using hydrophone arrays. Detailed focal depth and mechanism information, however, remain elusive due to the complexities of seismo-acoustic propagation paths. Nonetheless, recent analyses (Dziak, 2001; Park and Odom, 2001) indicate fault parameter information is contained within the T-wave signal packet. We investigate this relationship further by comparing an earthquake's T-wave duration and acoustic energy to seismic magnitude (NEIC) and radiation pattern (for events M>5) from the Harvard moment-tensor catalog. First results show earthquake energy is well represented by the acoustic energy of the T-waves, however T-wave codas are significantly influenced by acoustic propagation effects and do not allow a direct determination of the seismic magnitude of the earthquakes. Second, there appears to be a correlation between T-wave acoustic energy, azimuth from earthquake source to the hydrophone, and the radiation pattern of the earthquake's SH waves. These preliminary results indicate there is a relationship between the T-wave observations and earthquake source parameters, allowing for additional insights into T-wave

  2. Theory of the development of alternans in the heart during controlled diastolic interval pacing

    Science.gov (United States)

    Otani, Niels F.

    2017-09-01

    The beat-to-beat alternation in action potential durations (APDs) in the heart, called APD alternans, has been linked to the development of serious cardiac rhythm disorders, including ventricular tachycardia and fibrillation. The length of the period between action potentials, called the diastolic interval (DI), is a key dynamical variable in the standard theory of alternans development. Thus, methods that control the DI may be useful in preventing dangerous cardiac rhythms. In this study, we examine the dynamics of alternans during controlled-DI pacing using a series of single-cell and one-dimensional (1D) fiber models of alternans dynamics. We find that a model that combines a so-called memory model with a calcium cycling model can reasonably explain two key experimental results: the possibility of alternans during constant-DI pacing and the phase lag of APDs behind DIs during sinusoidal-DI pacing. We also find that these results can be replicated by incorporating the memory model into an amplitude equation description of a 1D fiber. The 1D fiber result is potentially concerning because it seems to suggest that constant-DI control of alternans can only be effective over only a limited region in space.

  3. Comparison of Spot and Time Weighted Averaging (TWA Sampling with SPME-GC/MS Methods for Trihalomethane (THM Analysis

    Directory of Open Access Journals (Sweden)

    Don-Roger Parkinson

    2016-02-01

    Full Text Available Water samples were collected and analyzed for conductivity, pH, temperature and trihalomethanes (THMs during the fall of 2014 at two monitored municipal drinking water source ponds. Both spot (or grab and time weighted average (TWA sampling methods were assessed over the same two day sampling time period. For spot sampling, replicate samples were taken at each site and analyzed within 12 h of sampling by both Headspace (HS- and direct (DI- solid phase microextraction (SPME sampling/extraction methods followed by Gas Chromatography/Mass Spectrometry (GC/MS. For TWA, a two day passive on-site TWA sampling was carried out at the same sampling points in the ponds. All SPME sampling methods undertaken used a 65-µm PDMS/DVB SPME fiber, which was found optimal for THM sampling. Sampling conditions were optimized in the laboratory using calibration standards of chloroform, bromoform, bromodichloromethane, dibromochloromethane, 1,2-dibromoethane and 1,2-dichloroethane, prepared in aqueous solutions from analytical grade samples. Calibration curves for all methods with R2 values ranging from 0.985–0.998 (N = 5 over the quantitation linear range of 3–800 ppb were achieved. The different sampling methods were compared for quantification of the water samples, and results showed that DI- and TWA- sampling methods gave better data and analytical metrics. Addition of 10% wt./vol. of (NH42SO4 salt to the sampling vial was found to aid extraction of THMs by increasing GC peaks areas by about 10%, which resulted in lower detection limits for all techniques studied. However, for on-site TWA analysis of THMs in natural waters, the calibration standard(s ionic strength conditions, must be carefully matched to natural water conditions to properly quantitate THM concentrations. The data obtained from the TWA method may better reflect actual natural water conditions.

  4. Apical hypertrophy associated with rapid T wave inversion on the electrocardiogram.

    Science.gov (United States)

    Yamanari, H; Saito, D; Mikio, K; Nakamura, K; Nanba, T; Morita, H; Mizuo, K; Sato, T; Ohe, T

    1995-01-01

    A 53-year-old man who had no chest pain and no family history of heart disease demonstrated a rapid T wave change on an electrocardiogram, from a positive T wave to a giant negative T wave, within 1 year. Echocardiography showed no left ventricular hypertrophy before or after the T wave change. Cine-magnetic resonance imaging revealed focal apical hypertrophy after the appearance of the giant negative T wave. Although T wave inversions sometimes develop within a short period in patients with hypertrophic cardiomyopathy, they are rare in a patient without hypertension or chest pain.

  5. Alternans by non-monotonic conduction velocity restitution, bistability and memory

    International Nuclear Information System (INIS)

    Kim, Tae Yun; Hong, Jin Hee; Heo, Ryoun; Lee, Kyoung J

    2013-01-01

    Conduction velocity (CV) restitution is a key property that characterizes any medium supporting traveling waves. It reflects not only the dynamics of the individual constituents but also the coupling mechanism that mediates their interaction. Recent studies have suggested that cardiac tissues, which have a non-monotonic CV-restitution property, can support alternans, a period-2 oscillatory response of periodically paced cardiac tissue. This study finds that single-hump, non-monotonic, CV-restitution curves are a common feature of in vitro cultures of rat cardiac cells. We also find that the Fenton–Karma model, one of the well-established mathematical models of cardiac tissue, supports a very similar non-monotonic CV restitution in a physiologically relevant parameter regime. Surprisingly, the mathematical model as well as the cell cultures support bistability and show cardiac memory that tends to work against the generation of an alternans. Bistability was realized by adopting two different stimulation protocols, ‘S1S2’, which produces a period-1 wave train, and ‘alternans-pacing’, which favors a concordant alternans. Thus, we conclude that the single-hump non-monotonicity in the CV-restitution curve is not sufficient to guarantee a cardiac alternans, since cardiac memory interferes and the way the system is paced matters. (paper)

  6. Identification of T-Waves in the Alboran Sea

    Science.gov (United States)

    Carmona, Enrique; Almendros, Javier; Alguacil, Gerardo; Soto, Juan Ignacio; Luzón, Francisco; Ibáñez, Jesús M.

    2015-11-01

    Analyses of seismograms from ~1,100 north-Moroccan earthquakes recorded at stations of the Red Sísmica de Andalucía (Southern Spain) reveal the systematic presence of late phases embedded in the earthquake codas. These phases have distinctive frequency contents, similar to the P and S spectra and quite different to the frequency contents of the earthquake codas. They are best detected at near-shore stations. Their amplitudes decay significantly with distance to the shoreline. The delays with respect to the P-wave onsets of the preceding earthquakes are consistently around 85 s. Late phases are only detected for earthquakes located in a small region of about 100 × 60 km centered at 35.4°N, 4.0°W near the northern coast of Morocco. Several hypotheses could, in principle, explain the presence of these late phases in the seismograms, for example, the occurrence of low-energy aftershocks, efficient wave reflections, or Rayleigh waves generated along the source-station paths. However, we conclude that the most-likely origin of these phases corresponds to the incidence of T-waves (generated by conversion from elastic to acoustic energy in the north-Moroccan coast) in the southern coast of the Iberian Peninsula. T-waves are thought to be generated by energy trapping in low-velocity channels along long oceanic paths; in this case, we demonstrate that they can be produced in much shorter paths as well. Although T-waves have been already documented in other areas of the Mediterranean Sea, this is the first time that they have been identified in the Alboran Sea.

  7. Investigation on the optimal magnetic field of a cusp electron gun for a W-band gyro-TWA

    Science.gov (United States)

    Zhang, Liang; He, Wenlong; Donaldson, Craig R.; Cross, Adrian W.

    2018-05-01

    High efficiency and broadband operation of a gyrotron traveling wave amplifier (gyro-TWA) require a high-quality electron beam with low-velocity spreads. The beam velocity spreads are mainly due to the differences of the electric and magnetic fields that the electrons withstand the electron gun. This paper investigates the possibility to decouple the design of electron gun geometry and the magnet system while still achieving optimal results, through a case study of designing a cusp electron gun for a W-band gyro-TWA. A global multiple-objective optimization routing was used to optimize the electron gun geometry for different predefined magnetic field profiles individually. Their results were compared and the properties of the required magnetic field profile are summarized.

  8. New approach for T-wave peak detection and T-wave end location in 12-lead paced ECG signals based on a mathematical model.

    Science.gov (United States)

    Madeiro, João P V; Nicolson, William B; Cortez, Paulo C; Marques, João A L; Vázquez-Seisdedos, Carlos R; Elangovan, Narmadha; Ng, G Andre; Schlindwein, Fernando S

    2013-08-01

    This paper presents an innovative approach for T-wave peak detection and subsequent T-wave end location in 12-lead paced ECG signals based on a mathematical model of a skewed Gaussian function. Following the stage of QRS segmentation, we establish search windows using a number of the earliest intervals between each QRS offset and subsequent QRS onset. Then, we compute a template based on a Gaussian-function, modified by a mathematical procedure to insert asymmetry, which models the T-wave. Cross-correlation and an approach based on the computation of Trapezium's area are used to locate, respectively, the peak and end point of each T-wave throughout the whole raw ECG signal. For evaluating purposes, we used a database of high resolution 12-lead paced ECG signals, recorded from patients with ischaemic cardiomyopathy (ICM) in the University Hospitals of Leicester NHS Trust, UK, and the well-known QT database. The average T-wave detection rates, sensitivity and positive predictivity, were both equal to 99.12%, for the first database, and, respectively, equal to 99.32% and 99.47%, for QT database. The average time errors computed for T-wave peak and T-wave end locations were, respectively, -0.38±7.12 ms and -3.70±15.46 ms, for the first database, and 1.40±8.99 ms and 2.83±15.27 ms, for QT database. The results demonstrate the accuracy, consistency and robustness of the proposed method for a wide variety of T-wave morphologies studied. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  9. Hyperthyroidism with dome-and-dart T wave: A case report: A care-compliant article.

    Science.gov (United States)

    Lai, Ping; Yuan, Jing-Ling; Xue, Jin-Hua; Qiu, Yue-Qun

    2017-02-01

    Dome-and-dart T waves (or bifid T waves) are a rare phenomenon in the surface electrocardiogram. These wave forms are mainly observed in patients with congenital heart disease such as atrial septal defect and ventricular septal defect. And hyperthyroidism who presented with an electrocardiogram that had dome-and-dart T waves in a precordial lead is never been reported. The patient presented with continuous tachycardia, palpitations, chest tightness, and headache for 4 days, and aggravated for 1 day. Hyperthyroidism. Methimazole. All symptoms were alleviated. Dome-and-dart or bifid T waves have been reported in the conventional 12-lead electrocardiograms in some patients with congenital heart disease. The case illustrated here, to the best of our knowledge, dome-and-dart or bifid T waves may associate with hyperthyroidism patients.

  10. Hyperthyroidism with dome-and-dart T wave: A case report

    Science.gov (United States)

    Lai, Ping; Yuan, Jing-ling; Xue, Jin-hua; Qiu, Yue-qun

    2017-01-01

    Abstract Rationale: Dome-and-dart T waves (or bifid T waves) are a rare phenomenon in the surface electrocardiogram. These wave forms are mainly observed in patients with congenital heart disease such as atrial septal defect and ventricular septal defect. And hyperthyroidism who presented with an electrocardiogram that had dome-and-dart T waves in a precordial lead is never been reported. Patient concerns: The patient presented with continuous tachycardia, palpitations, chest tightness, and headache for 4 days, and aggravated for 1 day. Diagnoses: Hyperthyroidism. Interventions: Methimazole. Outcomes: All symptoms were alleviated. Lessons: Dome-and-dart or bifid T waves have been reported in the conventional 12-lead electrocardiograms in some patients with congenital heart disease. The case illustrated here, to the best of our knowledge, dome-and-dart or bifid T waves may associate with hyperthyroidism patients. PMID:28178156

  11. New descriptors of T-wave morphology are independent of heart rate

    DEFF Research Database (Denmark)

    Andersen, Mads Peter; Xue, Joel Q; Graff, Claus

    2008-01-01

    from daytime Holter recordings. Duration parameters (QT, ToTe, TpTe, and others), a number of basic T-wave morphology parameters (amplitude, area, and others) as well as advanced morphology descriptors (asymmetry, flatness, and others) were measured automatically. Heart rate dependence was examined...... by means of analysis of covariance. The results showed clear heart rate dependence for the QT interval (R(2) = 0.53-0.57) and a moderate degree of heart rate dependence for the basic morphology parameters (amplitude, area, and others) (R(2) = 0.17-0.42). Both the advanced T-wave descriptors (asymmetry......T-wave morphology descriptors are sensitive to drug-induced changes and may be a useful addition to the QT interval in cardiac safety trials. Intrasubject heart rate dependence of T-wave morphology was investigated in a sample of 39 healthy individuals. Ten-second electrocardiograms were obtained...

  12. The T wave in the V10 precordial electrocardiographic lead is negative in healthy Chihuahua dogs.

    Science.gov (United States)

    Dijkstra, Marieke; Szatmári, Viktor

    2009-12-01

    The T wave polarity in the V10 precordial electrocardiographic (ECG) lead in Chihuahuas is described as positive in the veterinary literature. The aim of this study was to investigate the polarity of the T wave in the V10 precordial ECG lead in clinically healthy Chihuahuas. Our null hypothesis was that healthy Chihuahuas have a negative T wave in V10. In this prospective study, 67 healthy breeder-owned Chihuahuas were used. A physical examination, 10-lead ECG and an echocardiogram were performed on each dog. No cardio-respiratory abnormalities were revealed in any of the otherwise healthy dogs. Three out of 67 ECGs were of insufficient quality because of baseline artifacts due to movement of the animal. Two other ECGs showed a nearly iso-electric T wave in the V10 lead. The remaining 62 ECGs showed negative T waves in the V10 lead. Right ventricular hypertrophy was excluded with echocardiography in all dogs. In contrast to previous reports, we found that healthy Chihuahuas have negative T wave in the V10 precordial ECG lead.

  13. Isolation and Structural Elucidation of an Unknown compound from Murraya alternans (Kurz)Swingle

    International Nuclear Information System (INIS)

    Mya Aye; Hla Myoe Min; Sein Htun

    2002-02-01

    A new taxon of a species, Murraya alternans (Kurz) Swingle (Myanmar name, Naganaing) the series of Murraya belonging to the family Rutaceae had been recognized by Peter G. Waterman in 1986. However, this species has not been undertaken in botanical, medical, and chemical aspects. In this paper, scientific study on this taxon was chemically carried out for the first time. One of the unknown compounds was isolated from this species by column and high performance liquid chromatographic methods. It's partial structure could also be elucidated by spectral analysis such as IR, MS, H NMR(400MHz), C NMR (100MHz) spectrometry respectively. (author)

  14. Chaos for cardiac arrhythmias through a one-dimensional modulation equation for alternans

    Science.gov (United States)

    Dai, Shu; Schaeffer, David G.

    2010-01-01

    Instabilities in cardiac dynamics have been widely investigated in recent years. One facet of this work has studied chaotic behavior, especially possible correlations with fatal arrhythmias. Previously chaotic behavior was observed in various models, specifically in the breakup of spiral and scroll waves. In this paper we study cardiac dynamics and find spatiotemporal chaotic behavior through the Echebarria–Karma modulation equation for alternans in one dimension. Although extreme parameter values are required to produce chaos in this model, it seems significant mathematically that chaos may occur by a different mechanism from previous observations. PMID:20590327

  15. Atrial SERCA2a Overexpression Has No Affect on Cardiac Alternans but Promotes Arrhythmogenic SR Ca2+ Triggers.

    Science.gov (United States)

    Nassal, Michelle M J; Wan, Xiaoping; Laurita, Kenneth R; Cutler, Michael J

    2015-01-01

    Atrial fibrillation (AF) is the most common arrhythmia in humans, yet; treatment has remained sub-optimal due to poor understanding of the underlying mechanisms. Cardiac alternans precede AF episodes, suggesting an important arrhythmia substrate. Recently, we demonstrated ventricular SERCA2a overexpression suppresses cardiac alternans and arrhythmias. Therefore, we hypothesized that atrial SERCA2a overexpression will decrease cardiac alternans and arrhythmias. Adult rat isolated atrial myocytes where divided into three treatment groups 1) Control, 2) SERCA2a overexpression (Ad.SERCA2a) and 3) SERCA2a inhibition (Thapsigargin, 1μm). Intracellular Ca2+ was measured using Indo-1AM and Ca2+ alternans (Ca-ALT) was induced with a standard ramp pacing protocol. As predicted, SR Ca2+ reuptake was enhanced with SERCA2a overexpression (poverexpression or inhibition when compared to controls (p = 0.73). In contrast, SERCA2a overexpression resulted in increased premature SR Ca2+ (SCR) release compared to control myocytes (28% and 0%, p overexpression in atrial myocytes can increase SCR, which may be arrhythmogenic.

  16. Alternans and Spiral Breakup in an Excitable Reaction-Diffusion System: A Simulation Study.

    Science.gov (United States)

    Gani, M Osman; Ogawa, Toshiyuki

    2014-01-01

    The determination of the mechanisms of spiral breakup in excitable media is still an open problem for researchers. In the context of cardiac electrophysiological activities, spiral breakup exhibits complex spatiotemporal pattern known as ventricular fibrillation. The latter is the major cause of sudden cardiac deaths all over the world. In this paper, we numerically study the instability of periodic planar traveling wave solution in two dimensions. The emergence of stable spiral pattern is observed in the considered model. This pattern occurs when the heart is malfunctioning (i.e., ventricular tachycardia). We show that the spiral wave breakup is a consequence of the transverse instability of the planar traveling wave solutions. The alternans, that is, the oscillation of pulse widths, is observed in our simulation results. Moreover, we calculate the widths of spiral pulses numerically and observe that the stable spiral pattern bifurcates to an oscillatory wave pattern in a one-parameter family of solutions. The spiral breakup occurs far below the bifurcation when the maximum and the minimum excited states become more distinct, and hence the alternans becomes more pronounced.

  17. Triangulation of the monophasic action potential causes flattening of the electrocardiographic T-wave

    DEFF Research Database (Denmark)

    Bhuiyan, Tanveer Ahmed; Graff, Claus; Thomsen, Morten Bækgaard

    2012-01-01

    of the action potential under the effect of the IKr blocker sertindole and associated these changes to concurrent changes in the morphology of electrocardiographic T-waves in dogs. We show that, under the effect of sertindole, the peak changes in the morphology of action potentials occur at time points similar......It has been proposed that triangulation on the cardiac action potential manifests as a broadened, more flat and notched T-wave on the ECG but to what extent such morphology characteristics are indicative of triangulation is more unclear. In this paper, we have analyzed the morphological changes...... to those observed for the peak changes in T-wave morphology on the ECG. We further show that the association between action potential shape and ECG shape is dose-dependent and most prominent at the time corresponding to phase 3 of the action potential....

  18. Heritability of Tpeak-Tend Interval and T-wave Amplitude: A Twin Study

    DEFF Research Database (Denmark)

    Haarmark, Christian; Kyvik, Kirsten O; Vedel-Larsen, Esben

    2011-01-01

    BACKGROUND: -Tpeak-Tend interval (TpTe) and T-wave amplitude (Tamp) carry diagnostic and prognostic information regarding cardiac morbidity and mortality. Heart rate and QT interval are known to be heritable traits. The heritability of T-wave morphology parameters such as TpTe and Tamp is unknown...... interval, QTpeak and QTend interval) were measured and averaged over three consecutive beats in lead V5. TpTe was calculated as the QTend and QTpeak interval difference. Heritability was assessed using structural equation models adjusting for age, gender and BMI. All models were reducible to a model...... of additive genetics and unique environment. All variables had considerable genetic components. Adjusted heritability estimates were: TpTe 46%, Tamp lead V1 34%, Tamp lead V5 47%, RR interval 55%, QT interval 67% and QTcB 42%. CONCLUSIONS: -RR interval, QT-interval, T-wave amplitude and Tpeak-Tend interval...

  19. Trend Extraction in Functional Data of Amplitudes of R and T Waves in Exercise Electrocardiogram

    Science.gov (United States)

    Cammarota, Camillo; Curione, Mario

    The amplitudes of R and T waves of the electrocardiogram (ECG) recorded during the exercise test show both large inter- and intra-individual variability in response to stress. We analyze a dataset of 65 normal subjects undergoing ambulatory test. We model the dataset of R and T series in the framework of functional data, assuming that the individual series are realizations of a non-stationary process, centered at the population trend. We test the time variability of this trend computing a simultaneous confidence band and the zero crossing of its derivative. The analysis shows that the amplitudes of the R and T waves have opposite responses to stress, consisting respectively in a bump and a dip at the early recovery stage. Our findings support the existence of a relationship between R and T wave amplitudes and respectively diastolic and systolic ventricular volumes.

  20. Consequences of habitat fragmentation on genetic structure of Chamaedorea alternans (Arecaceae) palm populations in the tropical rain forests of Los Tuxtlas, Veracruz, Mexico

    OpenAIRE

    Peñaloza-Ramírez, Juan Manuel; Aguilar-Amezquita, Bernardo; Núñez-Farfán, Juan; Pérez-Nasser, Nidia; Albarrán-Lara, Ana Luisa; Oyama, Ken

    2016-01-01

    Abstract: Chamaedorea alternans is a palm species that has suffered from selective extraction, and habitat loss. We collected 11 populations from fragmented and conserved forest. We assess genetic variation of C. alternans, genetic exchange, differentiation, bottlenecks, effective population size and signals of natural selection. Genetic diversity was higher in conserved than in fragmented forest but not significant. Fragmentation did not play a significant role in genetic diversity, possibly...

  1. T-wave end detection using neural networks and Support Vector Machines.

    Science.gov (United States)

    Suárez-León, Alexander Alexeis; Varon, Carolina; Willems, Rik; Van Huffel, Sabine; Vázquez-Seisdedos, Carlos Román

    2018-05-01

    In this paper we propose a new approach for detecting the end of the T-wave in the electrocardiogram (ECG) using Neural Networks and Support Vector Machines. Both, Multilayer Perceptron (MLP) neural networks and Fixed-Size Least-Squares Support Vector Machines (FS-LSSVM) were used as regression algorithms to determine the end of the T-wave. Different strategies for selecting the training set such as random selection, k-means, robust clustering and maximum quadratic (Rényi) entropy were evaluated. Individual parameters were tuned for each method during training and the results are given for the evaluation set. A comparison between MLP and FS-LSSVM approaches was performed. Finally, a fair comparison of the FS-LSSVM method with other state-of-the-art algorithms for detecting the end of the T-wave was included. The experimental results show that FS-LSSVM approaches are more suitable as regression algorithms than MLP neural networks. Despite the small training sets used, the FS-LSSVM methods outperformed the state-of-the-art techniques. FS-LSSVM can be successfully used as a T-wave end detection algorithm in ECG even with small training set sizes. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Classification of the long-QT syndrome based on discriminant analysis of T-wave morphology

    DEFF Research Database (Denmark)

    Struijk, Johannes J.; Kanters, Jørgen K.; Andersen, M P

    2006-01-01

    The long QT syndrome (LQTS) is a genetic disorder, typically characterized by a prolonged QT interval in the ECG due to abnormal cardiac repolarization. LQTS may lead to syncopal episodes and sudden cardiac death. Various parameters based on T-wave morphology, as well as the QT interval itself ha...

  3. Effects of bilastine on T-wave morphology and the QTc interval

    DEFF Research Database (Denmark)

    Graff, Claus; Struijk, Johannes; Kanters, Jørgen K.

    2012-01-01

    The International Conference of Harmonisation (ICH) E14 guideline for thorough QT studies requires assessing the propensity of new non-antiarrhythmic drugs to affect cardiac repolarization. The present study investigates whether a composite ECG measure of T-wave morphology (Morphology Combination...

  4. Coexisting chaotic and multi-periodic dynamics in a model of cardiac alternans

    Energy Technology Data Exchange (ETDEWEB)

    Skardal, Per Sebastian, E-mail: skardals@gmail.com [Departament d' Enginyeria Informàtica i Matemàtiques, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Restrepo, Juan G., E-mail: juanga@colorado.edu [Department of Applied Mathematics, University of Colorado, Boulder, Colorado 80309 (United States)

    2014-12-15

    The spatiotemporal dynamics of cardiac tissue is an active area of research for biologists, physicists, and mathematicians. Of particular interest is the study of period-doubling bifurcations and chaos due to their link with cardiac arrhythmogenesis. In this paper, we study the spatiotemporal dynamics of a recently developed model for calcium-driven alternans in a one dimensional cable of tissue. In particular, we observe in the cable coexistence of regions with chaotic and multi-periodic dynamics over wide ranges of parameters. We study these dynamics using global and local Lyapunov exponents and spatial trajectory correlations. Interestingly, near nodes—or phase reversals—low-periodic dynamics prevail, while away from the nodes, the dynamics tend to be higher-periodic and eventually chaotic. Finally, we show that similar coexisting multi-periodic and chaotic dynamics can also be observed in a detailed ionic model.

  5. Interventricular dispersion in repolarization causes bifid T waves in dogs with dofetilide-induced long QT syndrome

    NARCIS (Netherlands)

    Meijborg, Veronique M F; Chauveau, Samuel; Janse, Michiel J; Anyukhovsky, Evgeny P; Danilo, Peter R; Rosen, Michael R; Opthof, Tobias; Coronel, Ruben

    BACKGROUND: Long QT2 (LQT2) syndrome is characterized by bifid (or notched) T waves, whose mechanism is not understood. OBJECTIVE: The purpose of this study was to test whether increased interventricular dispersion of repolarization induces bifid T waves. METHODS: We simultaneously recorded surface

  6. Interventricular dispersion in repolarization causes bifid T waves in dogs with dofetilide-induced long QT syndrome

    NARCIS (Netherlands)

    Meijborg, Veronique M. F.; Chauveau, Samuel; Janse, Michiel J.; Anyukhovsky, Evgeny P.; Danilo, Peter R.; Rosen, Michael R.; Opthof, Tobias; Coronel, Ruben

    2015-01-01

    Long QT2 (LQT2) syndrome is characterized by bifid (or notched) T waves, whose mechanism is not understood. The purpose of this study was to test whether increased interventricular dispersion of repolarization induces bifid T waves. We simultaneously recorded surface ECG and unipolar electrograms at

  7. Flattening of the electrocardiographic T-wave is a sign of proarrhythmic risk and a reflection of action potential triangulation

    DEFF Research Database (Denmark)

    Bhuiyan, Tanveer Ahmed; Graff, Claus; Kanters, J.K.

    2013-01-01

    Drug-induced triangulation of the cardiac action potential is associated with increased risk of arrhythmic events. It has been suggested that triangulation causes a flattening of the electrocardiographic T-wave but the relationship between triangulation, T-wave flattening and onset of arrhythmia ...

  8. Islands of spatially discordant APD alternans underlie arrhythmogenesis by promoting electrotonic dyssynchrony in models of fibrotic rat ventricular myocardium

    Science.gov (United States)

    Majumder, Rupamanjari; Engels, Marc C.; de Vries, Antoine A. F.; Panfilov, Alexander V.; Pijnappels, Daniël A.

    2016-04-01

    Fibrosis and altered gap junctional coupling are key features of ventricular remodelling and are associated with abnormal electrical impulse generation and propagation. Such abnormalities predispose to reentrant electrical activity in the heart. In the absence of tissue heterogeneity, high-frequency impulse generation can also induce dynamic electrical instabilities leading to reentrant arrhythmias. However, because of the complexity and stochastic nature of such arrhythmias, the combined effects of tissue heterogeneity and dynamical instabilities in these arrhythmias have not been explored in detail. Here, arrhythmogenesis was studied using in vitro and in silico monolayer models of neonatal rat ventricular tissue with 30% randomly distributed cardiac myofibroblasts and systematically lowered intercellular coupling achieved in vitro through graded knockdown of connexin43 expression. Arrhythmia incidence and complexity increased with decreasing intercellular coupling efficiency. This coincided with the onset of a specialized type of spatially discordant action potential duration alternans characterized by island-like areas of opposite alternans phase, which positively correlated with the degree of connexinx43 knockdown and arrhythmia complexity. At higher myofibroblast densities, more of these islands were formed and reentrant arrhythmias were more easily induced. This is the first study exploring the combinatorial effects of myocardial fibrosis and dynamic electrical instabilities on reentrant arrhythmia initiation and complexity.

  9. Influence of type of sport on cardiac repolarization assessed by electrocardiographic T-wave morphology combination score

    DEFF Research Database (Denmark)

    Glasius, Susanne; Graff, Claus; Ellervik, Christina

    2018-01-01

    was influenced by the sport performed. MATERIALS AND METHODS: Digital electrocardiograms of 469 young elite athletes were analyzed for T-wave asymmetry, flatness and notching, and combined in the MCS. Athletes >22years were compared to a sex-and age matched control group from the general population (N=198......). RESULTS: MCS increased with increasing endurance component of the sport performed ranging from 0.79±0.15 (low) to 0.92±0.21 (high) (p... suggests that sport induces repolarization changes detected by T-wave morphology, and a greater level of changes is seen in athletes from high endurance sports....

  10. New and Improved T-wave Morphology Parameters to Differentiate Healthy Individuals from those with Cardiomyopathy and Coronary Artery Disease

    Science.gov (United States)

    Greco, E. C.; Schlegel, T. T.; Arenare, B.; DePalma, J. L.; Starc, V.; Rahman, M. A.; Delgado, R.

    2007-01-01

    We investigated the ability of several known as well as new ECG repolarization parameters to differentiate healthy individuals from patients with obstructive coronary artery disease (CAD) and cardiomyopathy (CM). Advanced high-fidelity 12-lead ECG tests (approx. 5-min supine) were first performed on a "training set" of 99 individuals: 33 with ischemic or dilated CM and low ejection fraction (EF less than 40%); 33 with catheterization-proven obstructive CAD but normal EF; and 33 age-/gender-matched healthy controls. The following multiple parameters of T-wave morphology (TWM) were derived via signal averaging and singular value decomposition (SVD, which yields 8 eigenvalues, rho(sub 1) greater than rho(sub 2)...greater than rho(sub 8) and studied for their retrospective accuracy in detecting underlying disease: 1) Principal component analysis ratio of the T wave (T-PCA) = 100*rho(sub 2)/rho(sub 1); 2) Relative T-wave residuum (rTWR) = 100* SIGMA (rho(sub 4)(sup 2) +...+ rho(sub 8)(sup 2)); 3) Modified complexity ratio of the T wave (T-mCR) = 100*SIGMA(rho(sub 3)(sup 2) +...+rho(sb 8) (sup 2)); and 4) Normalized 3-dimensional volume of the T wave (nTV) = 100*(rho(sub 2)*rho(sub 3)/rho(sub 1)(sup 2). All TWM parameters significantly differentiated CAD from controls (p less than 0.0001), and also CM from controls (p less than 0.0001). Retrospective areas under the ROC curve were 0.77, 0.81, 0.82, and 0.83 (CAD vs. controls) and 0.93, 0.89, 0.95 and 0.96 (CM vs. controls) for T-PCA, rTWR, T-mCR and nTV respectively. The newer TWM parameters (T-mCR and nTV) thus outperformed the more established parameters (T-PCA and rTWR), presumably by putting a greater emphasis on the third T-wave eigenvalue, which in most healthy subjects has little energy compared to the first two eigenvalues. Subsequent prospective analyses have also yielded similar results, such that we conclude that diagnostic differentiation of pathology from non-pathology may be especially aided by detecting

  11. Dispersion of repolarization in canine ventricle and the electrocardiographic T wave: Tp-e interval does not reflect transmural dispersion

    NARCIS (Netherlands)

    Opthof, Tobias; Coronel, Ruben; Wilms-Schopman, Francien J. G.; Plotnikov, Alexei N.; Shlapakova, Iryna N.; Danilo, Peter; Rosen, Michael R.; Janse, Michiel J.

    2007-01-01

    BACKGROUND: The concept that the interval between the peak (T(peak)) and the end (T(end)) of the T wave (T(p-e)) is a measure of transmural dispersion of repolarization time is widely accepted but has not been tested rigorously by transmural mapping of the intact heart. OBJECTIVES: The purpose of

  12. Assessing common classification methods for the identification of abnormal repolarization using indicators of T-wave morphology and QT interval

    DEFF Research Database (Denmark)

    Shakibfar, Saeed; Graff, Claus; Ehlers, Lars Holger

    2012-01-01

    Various parameters based on QTc and T-wave morphology have been shown to be useful discriminators for drug induced I(Kr)-blocking. Using different classification methods this study compares the potential of these two features for identifying abnormal repolarization on the ECG. A group of healthy ...... the approach has not been tested in this setting....

  13. Covariate analysis of QTc and T-wave morphology: new possibilities in the evaluation of drugs that affect cardiac repolarization

    DEFF Research Database (Denmark)

    Graff, Claus; Struijk, Johannes J.; Matz, J

    2010-01-01

    This study adds the dimension of a T-wave morphology composite score (MCS) to the QTc interval-based evaluation of drugs that affect cardiac repolarization. Electrocardiographic recordings from 62 subjects on placebo and 400 mg moxifloxacin were compared with those from 21 subjects on 160 and 320...

  14. A history of drug-induced Torsades de Pointes is associated with T-wave morphological abnormalities

    DEFF Research Database (Denmark)

    Bhuiyan, Tanveer Ahmed; Graff, Claus; Kanters, Jørgen K.

    2018-01-01

    The hypothesis of the study is that Torsades de pointes (TdP) history can be better identified using T-wave morphology compared to Fridericia-corrected QT interval (QTcF) at baseline. ECGs were recorded at baseline and during sotalol challenge in 20 patients with a history of TdP (+TdP) and 16...

  15. Isolated T Wave Inversion in Lead aVL: An ECG Survey and a Case Report

    Directory of Open Access Journals (Sweden)

    Getaw Worku Hassen

    2015-01-01

    Full Text Available Background. Computerized electrocardiogram (ECG analysis has been of tremendous help for noncardiologists, but can we rely on it? The importance of ST depression and T wave inversions in lead aVL has not been emphasized and not well recognized across all specialties. Objective. This study’s goal was to analyze if there is a discrepancy of interpretation by physicians from different specialties and a computer-generated ECG reading in regard to a TWI in lead aVL. Methods. In this multidisciplinary prospective study, a single ECG with isolated TWI in lead aVL that was interpreted by the computer as normal was given to all participants to interpret in writing. The readings by all physicians were compared by level of education and by specialty to one another and to the computer interpretation. Results. A total of 191 physicians participated in the study. Of the 191 physicians 48 (25.1% identified and 143 (74.9% did not identify the isolated TWI in lead aVL. Conclusion. Our study demonstrated that 74.9% did not recognize the abnormality. New and subtle ECG findings should be emphasized in their training so as not to miss significant findings that could cause morbidity and mortality.

  16. A Parsimonious Model of the Rabbit Action Potential Elucidates the Minimal Physiological Requirements for Alternans and Spiral Wave Breakup.

    Science.gov (United States)

    Gray, Richard A; Pathmanathan, Pras

    2016-10-01

    Elucidating the underlying mechanisms of fatal cardiac arrhythmias requires a tight integration of electrophysiological experiments, models, and theory. Existing models of transmembrane action potential (AP) are complex (resulting in over parameterization) and varied (leading to dissimilar predictions). Thus, simpler models are needed to elucidate the "minimal physiological requirements" to reproduce significant observable phenomena using as few parameters as possible. Moreover, models have been derived from experimental studies from a variety of species under a range of environmental conditions (for example, all existing rabbit AP models incorporate a formulation of the rapid sodium current, INa, based on 30 year old data from chick embryo cell aggregates). Here we develop a simple "parsimonious" rabbit AP model that is mathematically identifiable (i.e., not over parameterized) by combining a novel Hodgkin-Huxley formulation of INa with a phenomenological model of repolarization similar to the voltage dependent, time-independent rectifying outward potassium current (IK). The model was calibrated using the following experimental data sets measured from the same species (rabbit) under physiological conditions: dynamic current-voltage (I-V) relationships during the AP upstroke; rapid recovery of AP excitability during the relative refractory period; and steady-state INa inactivation via voltage clamp. Simulations reproduced several important "emergent" phenomena including cellular alternans at rates > 250 bpm as observed in rabbit myocytes, reentrant spiral waves as observed on the surface of the rabbit heart, and spiral wave breakup. Model variants were studied which elucidated the minimal requirements for alternans and spiral wave break up, namely the kinetics of INa inactivation and the non-linear rectification of IK.The simplicity of the model, and the fact that its parameters have physiological meaning, make it ideal for engendering generalizable mechanistic

  17. Effects of negative T wave in electrocardiography on prognosis of post-myocardial infarction patients

    Directory of Open Access Journals (Sweden)

    Reza Karbasi-Afshar

    2013-03-01

    Full Text Available BACKGROUND: Negative T (NT wave in electrocardiography (ECG is one of the important factors in determining short- and long-term outcomes in patients with acute myocardial infarction (MI. In this study, we compared clinical and paraclinical findings in post-MI patients according to presence or absence of NT wave. METHODS: A cross-sectional study was conducted on patients with acute ST elevation MI who presented to Shahid Modares Hospital (Tehran, Iran during 2009-10. After undergoing streptokinase therapy, demographic characteristics and ECG and exercise test findings of the subjects were compared based on the presence or absence of NT wave. RESULTS: Overall, 116 patients including 69 cases with NT wave (NT group and 47 cases without NT wave (PT group were enrolled (mean age: 53.7 ± 7.1 vs. 54.1 ± 6.8 years old. Mortality rate during the first five days was 13% in the NT group and 29% in the PT group (P < 0.05. Ejection fraction values of the NT group were significantly higher than the PT group (P = 0.005. However, left ventricular end-diastolic diameter of the NT group was significantly less than the PT group (P = 0.005. Moreover, ST segment depression was significantly less frequent in the NT group compared to the PT group. CONCLUSION: Patients with ST elevation MI accompanying with NT wave in ECG versus have better prognosis and myocardial function than similar patients without NT wave. Therefore, invasive procedures should be recommended for patients without NT wave.   Keywords: Echocardiography, Exercise Test, Myocardial Infarction, Negative T Wave, Echocardiography

  18. Prognostic value of dynamic electrocardiographic T wave changes in non-ST elevation acute coronary syndrome.

    Science.gov (United States)

    Sarak, Bradley; Goodman, Shaun G; Yan, Raymond T; Tan, Mary K; Steg, Ph Gabriel; Tan, Nigel S; Fox, Keith A A; Udell, Jacob A; Brieger, David; Welsh, Robert C; Gale, Chris P; Yan, Andrew T

    2016-09-01

    To assess the relationship between the evolution of T wave inversion (TWI) on the 24-48 h postadmission ECG and the patient characteristics, management and clinical outcomes among those with non-ST elevation acute coronary syndrome (NSTE-ACS). We evaluated admission and 24-48 h follow-up ECGs of 7201 patients with NSTE-ACS from the prospective, multicentre Global Registry of Acute Coronary Events (GRACE) and Canadian ACS Registry I. We performed multivariable analyses to determine the association between new TWI (on follow-up ECG only), resolved TWI (on admission ECG only) and persistent TWI (on both admission and follow-up ECG) and inhospital and cumulative 6-month all-cause mortality. Patients with TWI were older, more likely to have cardiovascular risk factors, higher Killip class and GRACE risk scores. After adjustment for known prognostic factors, compared with patients presenting without TWI, new TWI was associated with significantly lower inhospital mortality (OR=0.60, 95% CI 0.38 to 0.95, p=0.029), whereas resolved (OR=1.06, 95% CI 0.65 to 1.75, p=0.81) and persistent (OR=0.73, 95% CI 0.48 to 1.11, p=0.14) TWI did not predict inhospital mortality. No TWI pattern independently predicted inhospital adverse cardiovascular events or cumulative 6-month mortality. In contrast, ST depression on the admission and follow-up ECG were independent predictors of inhospital and 6-month mortality. Across the spectrum of NSTE-ACS, TWI within 48 h of presentation was associated with high-risk clinical features, but its presence or dynamic change did not provide additional prognostic value beyond other established clinical predictors. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  19. T-wave inversions related to left ventricular basal hypertrophy and myocardial fibrosis in non-apical hypertrophic cardiomyopathy: A cardiovascular magnetic resonance imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiuyu, E-mail: cxy0202@126.com [Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037 (China); Zhao, Shihua, E-mail: zhaoshihua0202@126.com [Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037 (China); Zhao, Tao, E-mail: taozhao0202@126.com [Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037 (China); Lu, Minjie, E-mail: lmjkan@126.com [Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037 (China); Yin, Gang, E-mail: gangyin0202@126.com [Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037 (China); Jiang, Shiliang, E-mail: jiangsl-2011@163.com [Department of Radiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037 (China); Prasad, Sanjay, E-mail: s.prasad@rbht.nhs.uk [NIHR Biomedical Research Unit, Royal Brompton Hospital Sydney Street, London, SW3 6NP (United Kingdom)

    2014-02-15

    Objectives: To investigate the relationship between T-wave inversions and left ventricular (LV) segmental hypertrophy and myocardial fibrosis assessed by cardiovascular magnetic resonance (CMR) in patients with non-apical hypertrophic cardiomyopathy (HCM). Methods: 196 consecutive patients with non-apical HCM underwent late gadolinium enhancement (LGE) CMR and 12-lead electrocardiogram. The distribution and magnitude of LV segmental hypertrophy and LGE were assessed according to the AHA 17-segment model and analyzed in relation to T-wave inversions. Results: Of 196 HCM patients, 144 (73%) exhibited T-wave inversions. 144 (73%) patients had evidence of myocardial fibrosis as defined by LGE, and the prevalence of LGE was significantly higher in patients with T-wave inversions compared with those without T-wave inversions (78% vs. 59%, P = 0.008). T-wave inversions were related to basal anterior and basal anteroseptal LGE (20% vs. 10%, P = 0.04 and 68% vs. 46%, P = 0.005, respectively). In addition, T-wave inversions were associated with greater basal anteroseptal and basal inferior wall thickness (19.5 ± 4.7 mm vs. 16.7 ± 4.5 mm, P < 0.001 and 10.9 ± 3.3 mm vs. 9.6 ± 3.0 mm, P = 0.01, respectively). By logistic regression analysis, basal anteroseptal wall thickness and LGE were independent determinants of T-wave inversions (P = 0.005, P = 0.01, respectively). Conclusions: T-wave inversions in HCM are associated with LGE and wall thickness of the left ventricular basal segments. Moreover, basal anteroseptal wall thickness and LGE are independent determinants of T-wave inversions.

  20. T-wave inversions related to left ventricular basal hypertrophy and myocardial fibrosis in non-apical hypertrophic cardiomyopathy: A cardiovascular magnetic resonance imaging study

    International Nuclear Information System (INIS)

    Chen, Xiuyu; Zhao, Shihua; Zhao, Tao; Lu, Minjie; Yin, Gang; Jiang, Shiliang; Prasad, Sanjay

    2014-01-01

    Objectives: To investigate the relationship between T-wave inversions and left ventricular (LV) segmental hypertrophy and myocardial fibrosis assessed by cardiovascular magnetic resonance (CMR) in patients with non-apical hypertrophic cardiomyopathy (HCM). Methods: 196 consecutive patients with non-apical HCM underwent late gadolinium enhancement (LGE) CMR and 12-lead electrocardiogram. The distribution and magnitude of LV segmental hypertrophy and LGE were assessed according to the AHA 17-segment model and analyzed in relation to T-wave inversions. Results: Of 196 HCM patients, 144 (73%) exhibited T-wave inversions. 144 (73%) patients had evidence of myocardial fibrosis as defined by LGE, and the prevalence of LGE was significantly higher in patients with T-wave inversions compared with those without T-wave inversions (78% vs. 59%, P = 0.008). T-wave inversions were related to basal anterior and basal anteroseptal LGE (20% vs. 10%, P = 0.04 and 68% vs. 46%, P = 0.005, respectively). In addition, T-wave inversions were associated with greater basal anteroseptal and basal inferior wall thickness (19.5 ± 4.7 mm vs. 16.7 ± 4.5 mm, P < 0.001 and 10.9 ± 3.3 mm vs. 9.6 ± 3.0 mm, P = 0.01, respectively). By logistic regression analysis, basal anteroseptal wall thickness and LGE were independent determinants of T-wave inversions (P = 0.005, P = 0.01, respectively). Conclusions: T-wave inversions in HCM are associated with LGE and wall thickness of the left ventricular basal segments. Moreover, basal anteroseptal wall thickness and LGE are independent determinants of T-wave inversions

  1. Using left-ventricular-only pacing to eliminate T-wave oversensing in a biventricular implantable cardiac defibrillator.

    Science.gov (United States)

    Khoo, Clarence; Bennett, Matthew; Chakrabarti, Santabhanu; LeMaitre, John; Tung, Stanley K K

    2013-02-01

    A man aged 75 years and with nonischemic cardiomyopathy had implantation of a biventricular implantable cardiac defibrillator (ICD). Consistent biventricular pacing was limited by intermittent T-wave oversensing (TWOS). A strategy of left-ventricular-only pacing was used to eliminate TWOS. This strategy obviates the need to reduce ventricular sensitivity and thus may be an effective alternative to biventricular pacing complicated by TWOS. Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  2. Resurrection of Scolopendra longipes Wood and Scolopendra cubensis Saussure from synonymy with Scolopendra alternans Leach (Chilopoda, Scolopendromorpha, Scolopendridae): an enigmatic species-group needing phylogeographic analysis, with an overview on the origin and distribution of centipedes in the Caribbean region.

    Science.gov (United States)

    Mercurio, Randy J

    2016-05-12

    Resurrection of Scolopendra longipes Wood, 1862, and Scolopendra cubensis Saussure, 1860, from junior synonymy with Scolopendra alternans Leach, 1815, is proposed. A neotype specimen of Scolopendra longipes is designated. Scolopendra longipes has a restricted range from the Dry Tortugas up through the Florida Keys of Monroe County into the mainland Florida counties of Collier and Dade southeast to the Bahamas, while Scolopendra cubensis is endemic to Cuba. Characters distinguishing S. longipes, and S. cubensis from S. alternans are illustrated and compared using digital photography, micrography and morphometric data. It is suggested that what has been considered Scolopendra alternans from southern Florida through the Caribbean and into northern South America is probably an evolving species-group that has undergone major diversification sometime during the Paleocene and early Eocene ~65.5-50 million years ago (Ma), mainly due to geographic isolation caused by a combination of plate tectonics and 100,000 year cycles of glaciation/deglaciation.

  3. Mechano-electrical feedback explains T-wave morphology and optimizes cardiac pump function: insight from a multi-scale model.

    Science.gov (United States)

    Hermeling, Evelien; Delhaas, Tammo; Prinzen, Frits W; Kuijpers, Nico H L

    2012-01-01

    In the ECG, T- and R-wave are concordant during normal sinus rhythm (SR), but discordant after a period of ventricular pacing (VP). Experiments showed that the latter phenomenon, called T-wave memory, is mediated by a mechanical stimulus. By means of a mathematical model, we investigated the hypothesis that slow acting mechano-electrical feedback (MEF) explains T-wave memory. In our model, electromechanical behavior of the left ventricle (LV) was simulated using a series of mechanically and electrically coupled segments. Each segment comprised ionic membrane currents, calcium handling, and excitation-contraction coupling. MEF was incorporated by locally adjusting conductivity of L-type calcium current (g(CaL)) to local external work. In our set-up, g(CaL) could vary up to 25%, 50%, 100% or unlimited amount around its default value. Four consecutive simulations were performed: normal SR (with MEF), acute VP, sustained VP (with MEF), and acutely restored SR. MEF led to T-wave concordance in normal SR and to discordant T-waves acutely after restoring SR. Simulated ECGs with a maximum of 25-50% adaptation closely resembled those during T-wave memory experiments in vivo and also provided the best compromise between optimal systolic and diastolic function. In conclusion, these simulation results indicate that slow acting MEF in the LV can explain a) the relatively small differences in systolic shortening and mechanical work during SR, b) the small dispersion in repolarization time, c) the concordant T-wave during SR, and d) T-wave memory. The physiological distribution in electrophysiological properties, reflected by the concordant T-wave, may serve to optimize cardiac pump function. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. In Vivo and In Silico Investigation Into Mechanisms of Frequency Dependence of Repolarization Alternans in Human Ventricular Cardiomyocytes.

    Science.gov (United States)

    Zhou, Xin; Bueno-Orovio, Alfonso; Orini, Michele; Hanson, Ben; Hayward, Martin; Taggart, Peter; Lambiase, Pier D; Burrage, Kevin; Rodriguez, Blanca

    2016-01-22

    Repolarization alternans (RA) are associated with arrhythmogenesis. Animal studies have revealed potential mechanisms, but human-focused studies are needed. RA generation and frequency dependence may be determined by cell-to-cell variability in protein expression, which is regulated by genetic and external factors. To characterize in vivo RA in human and to investigate in silico using human models, the ionic mechanisms underlying the frequency-dependent differences in RA behavior identified in vivo. In vivo electrograms were acquired at 240 sites covering the epicardium of 41 patients at 6 cycle lengths (600-350 ms). In silico investigations were conducted using a population of biophysically detailed human models incorporating variability in protein expression and calibrated using in vivo recordings. Both in silico and in vivo, 2 types of RA were identified, with Fork- and Eye-type restitution curves, based on RA persistence or disappearance, respectively, at fast pacing rates. In silico simulations show that RA are strongly correlated with fluctuations in sarcoplasmic reticulum calcium, because of strong release and weak reuptake. Large L-type calcium current conductance is responsible for RA disappearance at fast frequencies in Eye-type (30% larger in Eye-type versus Fork-type; Psilico, 2 types of RA are identified, with RA persistence/disappearance as frequency increases. In silico, L-type calcium current and Na(+)/Ca(2+) exchanger current determine RA human cell-to-cell differences through intracellular and sarcoplasmic reticulum calcium regulation. © 2015 The Authors.

  5. Significance of deep T-wave inversions in asymptomatic athletes with normal cardiovascular examinations: practical solutions for managing the diagnostic conundrum.

    Science.gov (United States)

    Wilson, M G; Sharma, S; Carré, F; Charron, P; Richard, P; O'Hanlon, R; Prasad, S K; Heidbuchel, H; Brugada, J; Salah, O; Sheppard, M; George, K P; Whyte, G; Hamilton, B; Chalabi, H

    2012-11-01

    Preparticipation screening programmes for underlying cardiac pathologies are now commonplace for many international sporting organisations. However, providing medical clearance for an asymptomatic athlete without a family history of sudden cardiac death (SCD) is especially challenging when the athlete demonstrates particularly abnormal repolarisation patterns, highly suggestive of an inherited cardiomyopathy or channelopathy. Deep T-wave inversions of ≥ 2 contiguous anterior or lateral leads (but not aVR, and III) are of major concern for sports cardiologists who advise referring team physicians, as these ECG alterations are a recognised manifestation of hypertrophic cardiomyopathy (HCM) and arrhythmogenic right ventricular cardiomyopathy (ARVC). Subsequently, inverted T-waves may represent the first and only sign of an inherited heart muscle disease, in the absence of any other features and before structural changes in the heart can be detected. However, to date, there remains little evidence that deep T-wave inversions are always pathognomonic of either a cardiomyopathy or an ion channel disorder in an asymptomatic athlete following long-term follow-up. This paper aims to provide a systematic review of the prevalence of T-wave inversion in athletes and examine T-wave inversion and its relationship to structural heart disease, notably HCM and ARVC with a view to identify young athletes at risk of SCD during sport. Finally, the review proposes clinical management pathways (including genetic testing) for asymptomatic athletes demonstrating significant T-wave inversion with structurally normal hearts.

  6. Spatially Discordant Alternans and Arrhythmias in Tachypacing-Induced Cardiac Myopathy in Transgenic LQT1 Rabbits: The Importance of IKs and Ca2+ Cycling.

    Directory of Open Access Journals (Sweden)

    Emily Lau

    Full Text Available Remodeling of cardiac repolarizing currents, such as the downregulation of slowly activating K+ channels (IKs, could underlie ventricular fibrillation (VF in heart failure (HF. We evaluated the role of Iks remodeling in VF susceptibility using a tachypacing HF model of transgenic rabbits with Long QT Type 1 (LQT1 syndrome.LQT1 and littermate control (LMC rabbits underwent three weeks of tachypacing to induce cardiac myopathy (TICM. In vivo telemetry demonstrated steepening of the QT/RR slope in LQT1 with TICM (LQT1-TICM; pre: 0.26±0.04, post: 0.52±0.01, P<0.05. In vivo electrophysiology showed that LQT1-TICM had higher incidence of VF than LMC-TICM (6 of 11 vs. 3 of 11, respectively. Optical mapping revealed larger APD dispersion (16±4 vs. 38±6 ms, p<0.05 and steep APD restitution in LQT1-TICM compared to LQT1-sham (0.53±0.12 vs. 1.17±0.13, p<0.05. LQT1-TICM developed spatially discordant alternans (DA, which caused conduction block and higher-frequency VF (15±1 Hz in LQT1-TICM vs. 13±1 Hz in LMC-TICM, p<0.05. Ca2+ DA was highly dynamic and preceded voltage DA in LQT1-TICM. Ryanodine abolished DA in 5 out of 8 LQT1-TICM rabbits, demonstrating the importance of Ca2+ in complex DA formation. Computer simulations suggested that HF remodeling caused Ca2+-driven alternans, which was further potentiated in LQT1-TICM due to the lack of IKs.Compared with LMC-TICM, LQT1-TICM rabbits exhibit steepened APD restitution and complex DA modulated by Ca2+. Our results strongly support the contention that the downregulation of IKs in HF increases Ca2+ dependent alternans and thereby the risk of VF.

  7. Epicardial distribution of ST segment and T wave changes produced by stimulation of intrathoracic ganglia or cardiopulmonary nerves in dogs.

    Science.gov (United States)

    Savard, P; Cardinal, R; Nadeau, R A; Armour, J A

    1991-06-01

    Sixty-three ventricular epicardial electrograms were recorded simultaneously in 8 atropinized dogs during stimulation of acutely decentralized intrathoracic autonomic ganglia or cardiopulmonary nerves. Three variables were measured: (1) isochronal maps representing the epicardial activation sequence, (2) maps depicting changes in areas under the QRS complex and T wave (regional inhomogeneity of repolarization), and (3) local and total QT intervals. Neural stimulations did not alter the activation sequence but induced changes in the magnitude and polarity of the ST segments and T waves as well as in QRST areas. Stimulation of the same neural structure in different dogs induced electrical changes with different amplitudes and in different regions of the ventricles, except for the ventral lateral cardiopulmonary nerve which usually affected the dorsal wall of the left ventricle. Greatest changes occurred when the right recurrent, left intermediate medial, left caudal pole, left ventral lateral cardiopulmonary nerves and stellate ganglia were stimulated. Local QT durations either decreased or did not change, whereas total QT duration as measured using a root-mean-square signal did not change, indicating the regional nature of repolarization changes. Taken together, these data indicate that intrathoracic efferent sympathetic neurons can induce regional inhomogeneity of repolarization without prolonging the total QT interval.

  8. Automatic Identification of the Repolarization Endpoint by Computing the Dominant T-wave on a Reduced Number of Leads.

    Science.gov (United States)

    Giuliani, C; Agostinelli, A; Di Nardo, F; Fioretti, S; Burattini, L

    2016-01-01

    Electrocardiographic (ECG) T-wave endpoint (Tend) identification suffers lack of reliability due to the presence of noise and variability among leads. Tend identification can be improved by using global repolarization waveforms obtained by combining several leads. The dominant T-wave (DTW) is a global repolarization waveform that proved to improve Tend identification when computed using the 15 (I to III, aVr, aVl, aVf, V1 to V6, X, Y, Z) leads usually available in clinics, of which only 8 (I, II, V1 to V6) are independent. The aim of the present study was to evaluate if the 8 independent leads are sufficient to obtain a DTW which allows a reliable Tend identification. To this aim Tend measures automatically identified from 15-dependent-lead DTWs of 46 control healthy subjects (CHS) and 103 acute myocardial infarction patients (AMIP) were compared with those obtained from 8-independent-lead DTWs. Results indicate that Tend distributions have not statistically different median values (CHS: 340 ms vs. 340 ms, respectively; AMIP: 325 ms vs. 320 ms, respectively), besides being strongly correlated (CHS: ρ=0.97, AMIP: 0.88; Pautomatic Tend identification from DTW, the 8 independent leads can be used without a statistically significant loss of accuracy but with a significant decrement of computational effort. The lead dependence of 7 out of 15 leads does not introduce a significant bias in the Tend determination from 15 dependent lead DTWs.

  9. Hujjiyah Nazariyah Saddiaz-Żarāiʻfī al-Fiqh al- Islāmywatatbīquhāfī Qadāyāal-Maʹkȗlātwa al- Mashrȗbātwa al-Malbȗsāt

    Directory of Open Access Journals (Sweden)

    Imam Sujoko

    2017-12-01

    Full Text Available This  study  entitled:HujjiyahNazariyahSaddiaz-Żarāiʻfī  al-Fiqh  al-IslāmywatatbīquhāfīQadāyāal-  Maʹkȗlātwa  al-Mashrȗbātwa  al-Malbȗsāt,  deal  with  the  theory  ofSaddiaz-Żarāi.  The  study  tries  to  explore  its  meaning,  concept,  and  its  legality  in  Islamic  jurisprudence,  and  how  it  could  be  implemented in the cases of food, drink and clothing. Food, drink and clothing are the primary need  of  human,  but  there  are  some  cases  faced  by  Muslim  related  to  the  food,  drink  and  clothing.  For  example a Muslim will consume a product of food or drink or clothingthat produced from the non  Muslim country which they do not mind about the material; halal or haram. Should Muslim stops  from using those product, based on the theory of Saddiaz-Żarāiʻ?. The study found that the theory of  Saddiaz-Żarāiʻ,is a one of the Islamic resources regarding to the majority of Muslim scholar, event  there  are  some  differences  among  them  related  to  its  implementation.  And  some  Muslim  scholar  does  not  recognize  Saddiaz-Żarāiʻ  as  Islamic  resources.  But  for  those  who  agree  with  the  theory  ofSaddiaz-Żarāiʻ,they should understand the regulation of Saddiaz-Żarāiʻ. The methodology of study  is library study which is referring to the Islamic references such as texts of Qur’an and hadis and its  exegesis, Islamic jurisprudence books both classic and modern book, and fatwa of modern Muslim scholarsDOI: 10.15408/insaniyat.v2i1.6591

  10. Diagnostic Value of Electrocardiographic T Wave Inversion in Lead aVL in Diagnosing Coronary Artery Disease in Patients with Chronic Stable Angina

    Directory of Open Access Journals (Sweden)

    Hatem L. Farhan

    2010-04-01

    Full Text Available Objectives: The clinical value of T wave inversion in lead aVL in diagnosing coronary artery disease (CAD remains unclear. This study aims to investigate the correlation between aVL T wave inversion and CAD in patients with chronic stable angina.Methods: Electrocardiograms (ECGs of 257 consecutive patients undergoing coronary angiography were analyzed. All patients had chronic stable angina. All patients with secondary T wave inversion had been excluded (66 patients. The remaining 191 patients constituted the study population. Detailed ECG interpretation and coronary angiographic findings were conducted by experienced cardiologists.Results: T wave inversion in aVL was identified in 89 ECGs (46.8% with definite ischemic Q-ST-T changes in different leads in 97 ECGs (50.8%. Stand alone aVL T wave inversion was found in 27 ECGs (14.1% while ischemic changes in other leads with normal aVL were identified in 36 ECGs (18.8%. The incidence of CAD was 86.3%. Single, two- and multi-vessel CAD were found in 38.8%, 28.5% and 32.7% of cases respectively. The prevalence of left main, left anterior descending, left circumflex and right coronary arteries were 4.7%, 61.2%, 29.3% and 44.5%, respectively. T wave inversion in aVL was found to be the only ECG variable significantly predicting mid segment left anterior descending artery (LAD lesions (Odds Ratio 2.93, 95% Confidence Interval 1.59-5.37, p=0.001.Conclusion: This study provides new information relating to T wave inversion in lead aVL to mid segment LAD lesions. Implication of this simple finding may help in bedside diagnosis of CAD typically mid LAD lesions. However, further studies are needed to corroborate this finding.

  11. Deeply reinverted T wave at 14 days after the onset of first anterior acute myocardial infarction predicts improved left ventricular function at 6 months.

    Science.gov (United States)

    Yokoyama, Hiroaki; Tomita, Hirofumi; Nishizaki, Fumie; Hanada, Kenji; Shibutani, Shuji; Yamada, Masahiro; Abe, Naoki; Higuma, Takumi; Osanai, Tomohiro; Okumura, Ken

    2015-03-01

    Changes in electrocardiogram (ECG), especially in the ST segment and T wave, have been recognized as a noninvasive diagnostic tool for coronary flow or myocardial injury. A deeply inverted T wave at 14 days after successful percutaneous coronary intervention (PCI) in patients with ST-segment elevation acute myocardial infarction (STEMI) predicts improved left ventricular (LV) function at 6 months. We enrolled 112 consecutive patients (88 men, 63 ± 11 years) with first anterior STEMI who underwent successful PCI. A 12-lead ECG was recorded everyday from admission through 14 days. After PCI, the first T-wave inversion was observed within 2 days, and the second occurred at 14 days. We measured the maximum depth of the reinverted T wave (Neg-T) and divided the patients into 2 groups based on the median value of Neg-T: the deep group (≥0.6 mV, n = 62) and the nondeep group (wave in precordial leads at 6 months was more frequently observed in the deep than in the nondeep group (68% vs 46%, P = 0.02). Multivariate regression analysis showed that the Neg-T and max CPK-MB were independent contributors to LVEF at 6 months. A deeply reinverted T wave at 14 days after onset of first anterior STEMI can be a useful predictive marker for improved LV function at 6 months. © 2015 Wiley Periodicals, Inc.

  12. Detection of and response to a probable volcanogenic T-wave event swarm on the western Blanco Transform Fault Zone

    Science.gov (United States)

    Dziak, R.P.; Fox, C.G.; Embley, R.W.; Lupton, J.E.; Johnson, G.C.; Chadwick, W.W.; Koski, R.A.

    1996-01-01

    The East Blanco Depression (EBD), a pull-apart basin within the western Blanco Transform Fault Zone (BTFZ), was the site of an intense earthquake T-wave swarm that began at 1317Z on January 9, 1994. Although tectonically generated earthquakes occur frequently along the BTFZ, this swarm was unusual in that it was preceded and accompanied by periodic, low-frequency, long-duration acoustic signals, that originated from near the swarm epicenters. These tremor-like signals were very similar in character to acoustic energy produced by a shallow-submarine eruption near Socorro Island, a seamount several hundred km west of Baja, California. The ???69 earthquakes and ???400 tremor-like events at the EBD occurred sporadically, with two periods of peak activity occurring between January 5-16 and 27-31. The swarm-like character of the earthquakes and the similarity of the tremor activity to the Socorro eruption indicated that the EBD was undergoing an intrusion or eruption episode. On January 27, six CTD/rosette casts were conducted at the site. Water samples from two of the stations yielded anomalous 3He concentrations, with maxima at ???2800 m depth over the main basin. In June 1994 two camera tows within the basin yielded evidence of pillow-lava volcanism and hydrothermal deposits, but no conclusive evidence of a recent seafloor eruption. In September 1994, deployments of the U.S. Navy's Advanced Tethered Vehicle resulted in the discovery of an active hydrothermal mound on the flanks of a pillow-lava volcano. The hydrothermal mound consists of Fe-rich hydrothermal precipitate and bacterial mats. Temperatures to 60??C were measured 30 cm below the surface. This is the first discovery of active hydrothermal vents along an oceanic fracture zone. Although no conclusive evidence of volcanic activity associated with the T-wave event swarm was found during these response efforts, the EBD has been the site of recent seafloor eruptions. Copyright 1996 by the American Geophysical

  13. Relationship between normalization of negative T waves on exercise ECG and residual myocardial viability in patients with previous myocardial infarction and no post-infarction angina

    Energy Technology Data Exchange (ETDEWEB)

    Ajisaka, Ryuichi; Watanabe, Shigeyuki; Masuoka, Takeshi; Yamanouchi, Takayoshi; Saitoh, Takumi; Toyama, Masahiro; Takeda, Tohru; Itai, Yuji; Sugishita, Yasuro [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine

    1998-03-01

    The usefulness of normalization of negative T waves in exercise ECG was investigated as an index of myocardial viability in patients with previous myocardial infarction with no symptoms or ischemic ST-segment change during exercise test. A total of 39 patients, 20 with T-wave normalization (POS group) and 19 without T-wave normalization (NEG group) on exercise ECG, were studied. Myocardial viability was evaluated by thallium-201 single-photon emission computed tomography (SPECT) during exercise or at rest. We also assessed left ventricular ejection fraction (LVEF) by contrast ventriculography before (n=39) and after percutaneous transluminal coronary angioplasty (PTCA) (n=17). SPECT detected myocardial viability in 16 (80%) of the 20 patients in the POS group and in 4 (21%) of the 19 patients in the NEG group (p<0.01). LVEF increased after successful PTCA in the POS group (from 53{+-}13% to 63{+-}8%, p<0.025), but fell in the NEG group (from 57{+-}10% to 51{+-}8%). It is concluded that normalization of negative T waves on exercise ECG is a useful, simple index of myocardial viability in patients with previous myocardial infarction with no symptoms or ischemic ST-segment change during exercise testing. (author)

  14. Prolonged angina pectoris and persistent negative T waves in the precordial leads: response to atrial pacing and to methoxamine-induced hypertension

    International Nuclear Information System (INIS)

    Figueras, J.; Cinca, J.; Gutierrez, L.; Segura, R.; Rius, J.

    1983-01-01

    In 18 consecutive patients without a history of myocardial infarction (MI), prolonged angina pectoris with persistent negative T waves in the precordial leads was associated with a high frequency of in-hospital spontaneous angina (14 of 18, 78%), usually accompanied by S-T segment elevation, and occasionally in-hospital MI (4 of 18, 22%). Angina and MI always involved the electrocardiographic leads with negative T waves. Coronary arteriography, performed in 16 patients, revealed greater than or equal to 90% proximal diameter reduction of the left anterior descending (LAD) coronary artery in 14 patients. No patient had severe narrowing of all 3 major coronary arteries, but the 3 who had 100% LAD occlusion lacked collateral circulation. The ejection fraction was greater than or equal to 50% in 13 patients. Atrial pacing performed in 11 patients at an average rate of 142 beats/min produced a 1.0 mm S-T segment change in only 5 patients (45%), 3 of whom had an associated lactate production. Arterial systemic hypertension induced by methoxamine in 14 patients caused reversal of negative T waves without significant S-T segment shifts or chest pain and failed to elicit lactate extraction abnormalities in each of the 5 patients in whom it was determined. Thus, prolonged angina with persistent negative T waves in the precordial leads is almost invariably associated with a critical and proximal LAD obstruction, severe narrowing of 1 or 2 coronary arteries, and poor or absent collateral vessels

  15. Precise NMR measurement and stabilization system of magnetic field of a superconducting 7 T wave length shifter

    CERN Document Server

    Borovikov, V M; Karpov, G V; Korshunov, D A; Kuper, E A; Kuzin, M V; Mamkin, V R; Medvedko, A S; Mezentsev, N A; Repkov, V V; Shkaruba, V A; Shubin, E I; Veremeenko, V F

    2001-01-01

    The system of measurement and stabilization of the magnetic field in the superconducting 7 T wave length shifter (WLS), designed at Budker Institute of Nuclear Physics are described. The measurements are performed by nuclear magnetic resonance (NMR) magnetometer at two points of the WLS magnetic field. Stabilization of the field is provided by the current pumping system. The stabilization system is based on precise NMR measurement of magnetic field as a feedback signal for computer code which control currents inside the superconducting coils. The problem of the magnetic field measurements with NMR method consists in wide spread of field in the measured area (up to 50 Gs/mm), wide temperature range of WLS operating, small space for probe and influence of iron hysteresis. Special solid-state probes were designed to satisfy this requirements. The accuracy of magnetic field measurements at probe locations is not worse than 20 ppm. For the WLS field of 7 T the reproducibility of the magnetic field of 30 ppm has be...

  16. Ultra-Low Voltage Sixth-Order Low Pass Filter for Sensing the T-Wave Signal in ECGs

    Directory of Open Access Journals (Sweden)

    Panagiotis Bertsias

    2014-11-01

    Full Text Available An ultra-low voltage sixth-order low pass filter topology, suitable for sensing the T-wave signal in an electrocardiogram (ECG, is presented in this paper. This is realized using a cascade connection of second-order building blocks constructed from a sinh-domain two-integrator loop. The performance of the filter has been evaluated using the Cadence Analog Design Environment and the design kit provided by the Austria Mikro Systeme (AMS 0.35-µm CMOS process. The power consumption of filters was 7.21 nW, while a total harmonic distortion (THD level of 4% was observed for an input signal of 220 pA. The RMS value of the input referred noise was 0.43 pA, and the simulated value of the dynamic range (DR was 51.1 dB. A comparison with already published counterparts shows that the proposed topology offers the benefits of 0.5-V supply voltage operation and significantly improved power efficiency.

  17. An artificial vector model for generating abnormal electrocardiographic rhythms

    International Nuclear Information System (INIS)

    Clifford, Gari D; Nemati, Shamim; Sameni, Reza

    2010-01-01

    We present generalizations of our previously published artificial models for generating multi-channel ECG to provide simulations of abnormal cardiac rhythms. Using a three-dimensional vectorcardiogram (VCG) formulation, we generate the normal cardiac dipole for a patient using a sum of Gaussian kernels, fitted to real VCG recordings. Abnormal beats are specified either as perturbations to the normal dipole or as new dipole trajectories. Switching between normal and abnormal beat types is achieved using a first-order Markov chain. Probability transitions can be learned from real data or modeled by coupling to heart rate and sympathovagal balance. Natural morphology changes from beat-to-beat are incorporated by varying the angular frequency of the dipole as a function of the inter-beat (RR) interval. The RR interval time series is generated using our previously described model whereby time- and frequency-domain heart rate (HR) and heart rate variability characteristics can be specified. QT-HR hysteresis is simulated by coupling the Gaussian kernels associated with the T-wave in the model with a nonlinear factor related to the local HR (determined from the last n RR intervals). Morphology changes due to respiration are simulated by introducing a rotation matrix couple to the respiratory frequency. We demonstrate an example of the use of this model by simulating HR-dependent T-wave alternans (TWA) with and without phase-switching due to ectopy. Application of our model also reveals previously unreported effects of common TWA estimation methods

  18. Quantitative analysis of T-wave morphology increases confidence in drug-induced cardiac repolarization abnormalities: evidence from the investigational IKr inhibitor Lu 35-138

    DEFF Research Database (Denmark)

    Graff, Claus; Matz, Jørgen; Christensen, Ellen B

    2009-01-01

    prolongation. Seventy-nine healthy subjects were included in this parallel study. After a baseline day during which no drug was given, 40 subjects received an I(Kr)-blocking antipsychotic compound (Lu 35-138) on 7 consecutive days while 39 subjects received placebo. Resting ECGs were recorded and used...... to determine a combined measure of repolarization morphology (morphology combination score [MCS]), based on asymmetry, flatness, and notching. Replicate measurements were used to determine reliable change and study power for both measures. Lu 35-138 increased the QTc interval with corresponding changes in T......-wave morphology as determined by MCS. For subjects taking Lu 35-138, T-wave morphology was a more reliable indicator of I(Kr) inhibition than QTcF (chi(2) = 20.3, P = .001). At 80% study power for identifying a 5-millisecond placebo-adjusted change from baseline for QTcF, the corresponding study power for MCS...

  19. Sudden cardiac death and pump failure death prediction in chronic heart failure by combining ECG and clinical markers in an integrated risk model

    Science.gov (United States)

    Orini, Michele; Mincholé, Ana; Monasterio, Violeta; Cygankiewicz, Iwona; Bayés de Luna, Antonio; Martínez, Juan Pablo

    2017-01-01

    Background Sudden cardiac death (SCD) and pump failure death (PFD) are common endpoints in chronic heart failure (CHF) patients, but prevention strategies are different. Currently used tools to specifically predict these endpoints are limited. We developed risk models to specifically assess SCD and PFD risk in CHF by combining ECG markers and clinical variables. Methods The relation of clinical and ECG markers with SCD and PFD risk was assessed in 597 patients enrolled in the MUSIC (MUerte Súbita en Insuficiencia Cardiaca) study. ECG indices included: turbulence slope (TS), reflecting autonomic dysfunction; T-wave alternans (TWA), reflecting ventricular repolarization instability; and T-peak-to-end restitution (ΔαTpe) and T-wave morphology restitution (TMR), both reflecting changes in dispersion of repolarization due to heart rate changes. Standard clinical indices were also included. Results The indices with the greatest SCD prognostic impact were gender, New York Heart Association (NYHA) class, left ventricular ejection fraction, TWA, ΔαTpe and TMR. For PFD, the indices were diabetes, NYHA class, ΔαTpe and TS. Using a model with only clinical variables, the hazard ratios (HRs) for SCD and PFD for patients in the high-risk group (fifth quintile of risk score) with respect to patients in the low-risk group (first and second quintiles of risk score) were both greater than 4. HRs for SCD and PFD increased to 9 and 11 when using a model including only ECG markers, and to 14 and 13, when combining clinical and ECG markers. Conclusion The inclusion of ECG markers capturing complementary pro-arrhythmic and pump failure mechanisms into risk models based only on standard clinical variables substantially improves prediction of SCD and PFD in CHF patients. PMID:29020031

  20. T wave abnormalities, high body mass index, current smoking and high lipoprotein (a levels predict the development of major abnormal Q/QS patterns 20 years later. A population-based study

    Directory of Open Access Journals (Sweden)

    Sundstrom Johan

    2006-03-01

    Full Text Available Abstract Background Most studies on risk factors for development of coronary heart disease (CHD have been based on the clinical outcome of CHD. Our aim was to identify factors that could predict the development of ECG markers of CHD, such as abnormal Q/QS patterns, ST segment depression and T wave abnormalities, in 70-year-old men, irrespective of clinical outcome. Methods Predictors for development of different ECG abnormalities were identified in a population-based study using stepwise logistic regression. Anthropometrical and metabolic factors, ECG abnormalities and vital signs from a health survey of men at age 50 were related to ECG abnormalities identified in the same cohort 20 years later. Results At the age of 70, 9% had developed a major abnormal Q/QS pattern, but 63% of these subjects had not been previously hospitalized due to MI, while 57% with symptomatic MI between age 50 and 70 had no major Q/QS pattern at age 70. T wave abnormalities (Odds ratio 3.11, 95% CI 1.18–8.17, high lipoprotein (a levels, high body mass index (BMI and smoking were identified as significant independent predictors for the development of abnormal major Q/QS patterns. T wave abnormalities and high fasting glucose levels were significant independent predictors for the development of ST segment depression without abnormal Q/QS pattern. Conclusion T wave abnormalities on resting ECG should be given special attention and correlated with clinical information. Risk factors for major Q/QS patterns need not be the same as traditional risk factors for clinically recognized CHD. High lipoprotein (a levels may be a stronger risk factor for silent myocardial infarction (MI compared to clinically recognized MI.

  1. A New Wavelet-Based ECG Delineator for the Evaluation of the Ventricular Innervation

    DEFF Research Database (Denmark)

    Cesari, Matteo; Mehlsen, Jesper; Mehlsen, Anne-Birgitte

    2017-01-01

    T-wave amplitude (TWA) has been proposed as a marker of the innervation of the myocardium. Until now, TWA has been calculated manually or with poor algorithms, thus making its use not efficient in a clinical environment. We introduce a new wavelet-based algorithm for the delineation QRS complexes...

  2. Use of left ventricular ejection fraction or wall-motion score index in predicting arrhythmic death in patients following an acute myocardial infarction. The TRACE Study Group

    DEFF Research Database (Denmark)

    Køber, L; Torp-Pedersen, C; Elming, H

    1997-01-01

    on the correlation between arrhythmic death and "sudden unexpected death" defined as death within 1 hour of onset of new symptoms. Assessment of late potentials, heart rate variability (HRV), T wave alternans, arrhythmias seen on Holter monitoring or during exercise testing, electrophysiological testing...

  3. Electrocardiographic Changes in Certain Cardiovascular Physiological and Pathological Settings. Impact on Coronary Artery Bypass Grafting

    Directory of Open Access Journals (Sweden)

    Dimitar Simov

    2016-03-01

    Full Text Available Review on electrocardiographic changes provoked by aging, diagnostic tests, cardiac surgery, hemodialysis, diabetes, etc., is the objective of the current material. Several electrocardiographic (ECG parameters that are well known risk markers of arrhythmias, incidental heart failure and sudden cardiac death (SCD are discussed: QRS amplitude, QRS morphology, QRS duration, QRS alternans, T-wave amplitude, T-wave morphology, T-wave alternans, negative T-waves, 3D-spatial angle between maximal QRS and T vectors of the vectorcardiographic loops, ST-segment elevation, QT-interval dispersion, and heart rate. All reviewed parameters are compared with the results on the ECG-alterations, induced by coronary artery bypass grafting (CABG surgery. Two parameters showed an improvement in the patients' condition: QRS-T angle and cardiac autonomic innervation while two others (T-wave alternans and heart rate indicated deterioration. We tend to assume that the deterioration in this early post-operative period is an effect of the post-surgery trauma. We speculate that this effect will fade away in a period of a month and more after surgery, and we intend to conduct such a research in the future. The analysis of ECG's changes will help to better assess the impact of the CABG surgery.

  4. Superconducting 7 T Wave Length Shifter for BESSY-II

    CERN Document Server

    Borovikov, V M; Fedurin, M G; Repkov, V V; Karpov, G V; Kulipanov, G N; Kuzin, M V; Mezentsev, N A; Shkaruba, V A; Krämer, Dietrich; Richter, D

    2001-01-01

    A superconducting 3-pole Wave Length Shifter (WLS) with a maximum field of 7 T was fabricated and tested by BINP in collaboration with BESSY-II. The radiation point is fixed in the center of WLS at any field level by using two correctors. The magnetic field is stabilized with an accuracy of 10 sup - sup 4 at 7 T by a feedback system based on NMR probes and magnetic flux pumps. Persistent current operation mode is enabled by using superconducting persistent keys. The magnetic field homogeneity of 10 sup - sup 4 at 7 T is obtained as a result of shimming in the aperture of the magnet. A protection system based on cold diodes and dump resistors prevents the destruction of superconducting coils during the quench. Two screens with temperatures of 20 and 60 K cooled by cooling machine, two recondensers, HTSC current leads and cevlar suspensions of helium volume are used to decrease liquid helium consumption. The main features and operating mode of the WLS are described.

  5. Optimization of a triode-type cusp electron gun for a W-band gyro-TWA

    Science.gov (United States)

    Zhang, Liang; Donaldson, Craig R.; He, Wenlong

    2018-04-01

    A triode-type cusp electron gun was optimized through numerical simulations for a W-band gyrotron traveling wave amplifier. An additional electrode in front of the cathode could switch the electron beam on and off instantly when its electric potential is properly biased. An optimal electron beam of current 1.7 A and a velocity ratio (alpha) of 1.12 with an alpha spread of ˜10.7% was achieved when the triode gun was operated at 40 kV.

  6. Design and realization of the AMANDA software trigger for the TWA data readout system; Entwurf und Realisierung des AMANDA-Softwaretriggers fuer das TWR-Datenauslese-System

    Energy Technology Data Exchange (ETDEWEB)

    Messarius, Timo

    2006-07-15

    The thesis begins with a short introduction in the theory of astroparticle physics. Especially the processes, which lead to signal respectively background events in neutrino detectors, are discussed. Thereafter follows the descripotion of the basing detection principle and the detectors AMANDA and IceCube. The following chapter considers the two data-acquisition systems of the AMANDA detector and explains the motivation for the construction of a new data-acquisition system. The newly designed trigger system is then extensively treated. First a completely on software basing system is discussed, and then the implemented version is considered more detailedly. A procedure to detect and to mark events from atmospheric muons directly on trigger level is presented.

  7. Effect of Nalmefene 20 and 80 mg on the corrected QT interval and T-wave morphology

    DEFF Research Database (Denmark)

    Matz, Jørgen; Graff, Claus; Vainio, Petri J.

    2011-01-01

    Nalmefene is an orally administered competitive opioid receptor antagonist targeted at reducing alcohol consumption in alcohol-dependent patients. As part of the regulatory requirements for drug approval, the potential of novel compounds for causing unwanted proarrhythmia should be studied...

  8. Effect of nalmefene 20 and 80 mg on the corrected QT interval and T-wave morphology

    DEFF Research Database (Denmark)

    Matz, Jørgen; Graff, Claus; Vainio, Petri J.

    2011-01-01

    Nalmefene is an orally administered competitive opioid receptor antagonist targeted at reducing alcohol consumption in alcohol-dependent patients. As part of the regulatory requirements for drug approval, the potential of novel compounds for causing unwanted proarrhythmia should be studied...

  9. Untitled

    Indian Academy of Sciences (India)

    . TWA2 Surface chemical analysis Wide ranging reference materials, metallic UK and non-metallic. TWA3 Ceramics Alumina, zirconia-alumina USA. TWA4 Polymer blends Polycarbonate/polyethylene blend, Canada. Orgalloy R-6000 ...

  10. Exhaustion-related changes in cardiovascular and cortisol reactivity to acute psychosocial stress

    DEFF Research Database (Denmark)

    Jönsson, Peter; Österberg, Kai; Wallergård, Mattias

    2015-01-01

    -pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) activations in both V-TSST sessions, together with habituation of cortisol and heart rate in the second session, but without any significant group differences. However, the former ED patients showed considerable variation in self-reported signs...... cortisol samples were collected. In addition, high frequency heart rate variability (HF-HRV), heart rate (HR), t-wave amplitude (TWA), and α-amylase were assessed to examine stress reactivity and habituation in the autonomic nervous system (ANS). The initial analyses showed clear hypothalamic...... of exhaustion (SMBQ). This led us to assign former ED patients with lower ratings into the low SMBQ group (LOWS) and those with higher ratings to the high SMBQ group (HIGHS). When repeating the analyses a different picture emerged; the HIGHS showed a lower cortisol response to the V-TSST than did the LOWS. Both...

  11. Identifying drug-induced repolarization abnormalities from distinct ECG patterns in congenital long QT syndrome: a study of sotalol effects on T-wave morphology

    DEFF Research Database (Denmark)

    Graff, Claus; Andersen, Mads P; Xue, Joel Q

    2009-01-01

    BACKGROUND: The electrocardiographic QT interval is used to identify drugs with potential harmful effects on cardiac repolarization in drug trials, but the variability of the measurement can mask drug-induced ECG changes. The use of complementary electrocardiographic indices of abnormal repolariz......BACKGROUND: The electrocardiographic QT interval is used to identify drugs with potential harmful effects on cardiac repolarization in drug trials, but the variability of the measurement can mask drug-induced ECG changes. The use of complementary electrocardiographic indices of abnormal...... are typical ECG patterns in LQT2. Blinded to labels, the new morphology measures were tested in a third group of 39 healthy subjects receiving sotalol. Over 3 days the sotalol group received 0, 160 and 320 mg doses, respectively, and a 12-lead Holter ECG was recorded for 22.5 hours each day. Drug...... with QTcF, p ECG patterns in LQT2 carriers effectively quantified repolarization changes induced by sotalol. Further studies are needed to validate whether this measure has...

  12. Structure Elucidation of A New Coumarin Type Compound, Alternamin, Isolated from the Plant (Murraya Alternans (Kurz) Swingle) Having The Antidote Activity on Snake Venoms

    International Nuclear Information System (INIS)

    Hla Myo Min; Mya Aye

    2004-06-01

    The structure of a new coumarin type compound isolated from the entitled species was elucidated by the full spectral analysis consisting of FTIR, 1H NMR, DQF COSY, 13C NMR, DEPT, EIMS (HR-EIMS), HMQC and HMBC. The antidote activities of the fresh juice and the ethanolic extract of the plant, and the isolated compound alternamin were also determined

  13. Low-dose β-blocker in combination with milrinone safely improves cardiac function and eliminates pulsus alternans in patients with acute decompensated heart failure.

    Science.gov (United States)

    Kobayashi, Shigeki; Susa, Takehisa; Tanaka, Takeo; Murakami, Wakako; Fukuta, Seiko; Okuda, Shinichi; Doi, Masahiro; Wada, Yasuaki; Nao, Tomoko; Yamada, Jutaro; Okamura, Takayuki; Yano, Masafumi; Matsuzaki, Masunori

    2012-01-01

    The purpose of this study was to determine whether a low-dose β-blocker, in combination with milrinone, improves cardiac function in acute decompensated heart failure (ADHF) with tachycardia. Twenty ADHF patients (New York Heart Association classification III, n=1, and IV, n=19; heart rate [HR], 107±12 beats/min; left ventricular ejection fraction, 24±7%; cardiac index [CI], 2.2±0.6 L·min(-1)·m(-2); pulmonary capillary wedge pressure [PCWP], 26±8 mmHg) were enrolled in this study. The patients first underwent conventional therapy with milrinone, vasodilators and diuretics; landiolol (1.5-6.0 µg·kg(-1)·min(-1); i.v.), which is an ultra-short-acting β(1)-selective blocker, was then added to the treatment regimen to study its effect on hemodynamics. Low-dose landiolol (1.5 µg·kg(-1)·min(-1)) significantly reduced HR by 11% without changing blood pressure (BP) and CI, whereas higher doses (≥3.0 µg·kg(-1)·min(-1)) tended to decrease BP and CI while increasing PCWP and systemic vascular resistance. After treatment with landiolol (1.5 µg·kg(-1)·min(-1)), hemodynamic parameters such as PCWP, stroke volume index, SvO(2), rate pressure product, filling time/RR, E/e', and Tei index were significantly improved. A low-dose β-blocker in combination with milrinone improved cardiac function in ADHF patients with tachycardia; therefore, it may be considered as an adjunct therapy for use when standard therapy with milrinone is not effective at slowing HR.

  14. Detrended Fluctuation Analysis on Cardiac Pulses in Both, Animal Models and Humans: A Computation for an Early Prognosis of Cardiovascular Disease

    Directory of Open Access Journals (Sweden)

    Toru Yazawa

    2008-04-01

    Full Text Available We analyzed the heartbeat interval by the detrended fluctuation analysis (DFA in models and humans. In models, the myocardium of the healthy heart contracted regularly. The deteriorated heart model, however, showed alternating beats so-called "alternans." The DFA revealed that if the heart is having "alternans" exhibited there is a declined scaling exponent (~0.5. In humans, the heart that had "alternans" also showed a low scaling exponent (~0.6. We consider that the coexistence of "alternans" and a low scaling exponent can be a risk marker in predictive and preventative diagnosis, supporting the idea that "alternans" can be a harbinger of sudden death.

  15. Noninvasive risk stratification of lethal ventricular arrhythmias and sudden cardiac death after myocardial infarction

    Directory of Open Access Journals (Sweden)

    Kenji Yodogawa, MD

    2014-08-01

    Full Text Available Prediction of lethal ventricular arrhythmias leading to sudden cardiac death is one of the most important and challenging problems after myocardial infarction (MI. Identification of MI patients who are prone to ventricular tachyarrhythmias allows for an indication of implantable cardioverter-defibrillator placement. To date, noninvasive techniques such as microvolt T-wave alternans (MTWA, signal-averaged electrocardiography (SAECG, heart rate variability (HRV, and heart rate turbulence (HRT have been developed for this purpose. MTWA is an indicator of repolarization abnormality and is currently the most promising risk-stratification tool for predicting malignant ventricular arrhythmias. Similarly, late potentials detected by SAECG are indices of depolarization abnormality and are useful in risk stratification. However, the role of SAECG is limited because of its low predictive accuracy. Abnormal HRV and HRT patterns reflect autonomic disturbances, which may increase the risk of lethal ventricular arrhythmias, but the existing evidence is insufficient. Further studies of noninvasive assessment may provide a new insight into risk stratification in post-MI patients.

  16. Sudden Cardiac Risk Stratification with Electrocardiographic Indices - A Review on Computational Processing, Technology Transfer, and Scientific Evidence

    Directory of Open Access Journals (Sweden)

    Francisco Javier eGimeno-Blanes

    2016-03-01

    Full Text Available Great effort has been devoted in recent years to the development of sudden cardiac risk predictors as a function of electric cardiac signals, mainly obtained from the electrocardiogram (ECG analysis. But these prediction techniques are still seldom used in clinical practice, partly due to its limited diagnostic accuracy and to the lack of consensus about the appropriate computational signal processing implementation. This paper addresses a three-fold approach, based on ECG indexes, to structure this review on sudden cardiac risk stratification. First, throughout the computational techniques that had been widely proposed for obtaining these indexes in technical literature. Second, over the scientific evidence, that although is supported by observational clinical studies, they are not always representative enough. And third, via the limited technology transfer of academy-accepted algorithms, requiring further meditation for future systems. We focus on three families of ECG derived indexes which are tackled from the aforementioned viewpoints, namely, heart rate turbulence, heart rate variability, and T-wave alternans. In terms of computational algorithms, we still need clearer scientific evidence, standardizing, and benchmarking, siting on advanced algorithms applied over large and representative datasets. New scenarios like electronic health recordings, big data, long-term monitoring, and cloud databases, will eventually open new frameworks to foresee suitable new paradigms in the near future.

  17. In silico prediction of sex-based differences in human susceptibility to cardiac ventricular tachyarrhythmias

    Directory of Open Access Journals (Sweden)

    Pei-Chi eYang

    2012-09-01

    Full Text Available Sex-based differences in human susceptibility to cardiac ventricular tachyarrhythmias likely result from the emergent effects of multiple intersecting processes that fundamentally differ in male and female hearts. Included are measured differences in the genes encoding key cardiac ion channels and effects of sex steroid hormones to acutely modify electrical activity. At the genome scale, human females have recently been shown to have lower expression of genes encoding key cardiac repolarizing potassium currents and connexin43, the primary ventricular gap junction subunit. Human males and females also have distinct sex steroid hormones. Here, we developed mathematical models for male and female ventricular human heart cells by incorporating experimentally determined genomic differences and effects of sex steroid hormones into the O’Hara-Rudy model. These male and female model cells and tissues then were used to predict how various sex-based differences underlie arrhythmia risk. Genomic-based differences in ion channel expression were alone sufficient to determine longer female cardiac action potential durations (APD in both epicardial and endocardial cells compared to males. Subsequent addition of sex steroid hormones exacerbated these differences, as testosterone further shortened APDs, while estrogen and progesterone application resulted in disparate effects on APDs. Our results indicate that incorporation of experimentally determined genomic differences from human hearts in conjunction with sex steroid hormones are consistent with clinically observed differences in QT interval, T-wave shape and morphology, and critically, in the higher vulnerability of adult human females to Torsades de Pointes type arrhythmias. The model suggests that female susceptibility to alternans stems from longer female action potentials, while reentrant arrhythmia derives largely from sex-based differences in conduction play an important role in arrhythmia

  18. Istaroxime, a positive inotropic agent devoid of proarrhythmic properties in sensitive chronic atrioventricular block dogs.

    Science.gov (United States)

    Bossu, Alexandre; Kostense, Amée; Beekman, Henriette D M; Houtman, Marien J C; van der Heyden, Marcel A G; Vos, Marc A

    2018-05-10

    Current inotropic agents in heart failure therapy associate with low benefit and significant adverse effects, including ventricular arrhythmias. Istaroxime, a novel Na + /K + -transporting ATPase inhibitor, also stimulates SERCA2a activity, which would confer improved inotropic and lusitropic properties with less proarrhythmic effects. We investigated hemodynamic, electrophysiological and potential proarrhythmic and antiarrhythmic effects of istaroxime in control and chronic atrioventricular block (CAVB) dogs sensitive to drug-induced Torsades de Pointes arrhythmias (TdP). In isolated normal canine ventricular cardiomyocytes, istaroxime (0.3-10 μM) evoked no afterdepolarizations and significantly shortened action potential duration (APD) at 3 and 10 μM. Istaroxime at 3 μg/kg/min significantly increased left ventricular (LV) contractility (dP/dt + ) and relaxation (dP/dt-) respectively by 81 and 94% in anesthetized control dogs (n = 6) and by 61 and 49% in anesthetized CAVB dogs (n = 7) sensitive to dofetilide-induced TdP. While istaroxime induced no ventricular arrhythmias in control conditions, only single ectopic beats occurred in 2/7 CAVB dogs, which were preceded by increase of short-term variability of repolarization (STV) and T wave alternans in LV unipolar electrograms. Istaroxime pre-treatment (3 μg/kg/min for 60 min) did not alleviate dofetilide-induced increase in repolarization and STV, and mildly reduced incidence of TdP from 6/6 to 4/6 CAVB dogs. In six CAVB dogs with dofetilide-induced TdP, administration of istaroxime (90 μg/kg/5 min) suppressed arrhythmic episodes in two animals. Taken together, inotropic and lusitropic properties of istaroxime in CAVB dogs were devoid of significant proarrhythmic effects in sensitive CAVB dogs, and istaroxime provides a moderate antiarrhythmic efficacy in prevention and suppression of dofetilide-induced TdP. Copyright © 2018. Published by Elsevier Ltd.

  19. The Role of Person-Environment Fit in the Job Satisfaction and Tenure Intentions of African American Employees

    Science.gov (United States)

    Lyons, Heather Z.; O'Brien, Karen M.

    2006-01-01

    In light of speculation that the determinants of job satisfaction and tenure for African American employees may not be adequately captured by the theory of work adjustment (TWA; Dawis & Lofquist, 1984), in the present study the authors tested assumptions of the TWA with an African American sample by (a) examining the strength of fit-satisfaction…

  20. The Interaction of Work Adjustment and Attachment Theory: Employment Counseling Implications

    Science.gov (United States)

    Renfro-Michel, Edina L.; Burlew, Larry D.; Robert, Tracey

    2009-01-01

    Career development is a lifelong process beginning with career choice. However, career choice alone does not guarantee career success. Rather than focus on choosing a career, the theory of work adjustment (TWA) focuses on the process of becoming an exemplary employee through each stage of an individual's career. Within TWA, employee relationships…

  1. C:\\My Documents\\African Heath S

    African Journals Online (AJOL)

    African Health Sciences Vol 3 No 1 April 2003. 1. Editorial. Its now official: ... between students and parents increased the odds of condom use. ... of school health,. Wandera and Twa-Twa's study of oral health4 of ... and knowledge. Go for it!

  2. New Parallaxes and a Convergence Analysis for the TW Hya Association

    Science.gov (United States)

    Donaldson, J. K.; Weinberger, A. J.; Gagné, J.; Faherty, J. K.; Boss, A. P.; Keiser, S. A.

    2016-12-01

    The TW Hya Association (TWA) is a nearby stellar association with an age of ˜5-10 Myr. This is an important age for studying the late stages of star and planet formation. We measure the parallaxes of 14 candidate members of TWA. That brings to 38 the total number of individual stars with fully measured kinematics, I.e., proper motion, radial velocity, and parallax, to describe their motions through the Galaxy. We analyze these kinematics to search for convergence to a smaller volume in the past, but we find that the association is never much more compact than it is at present. We show that it is difficult to measure traceback ages for associations such as TWA that have expected velocity dispersions of 1-2 km s-1 with typical measurement uncertainties. We also use our stellar distances and pre-main-sequence evolutionary tracks to find the average age of the association of 7.9 ± 1.0 Myr. Additionally, our parallax measurement of TWA 32 indicates that it should be considered a bona fide member of TWA. Two new candidate members have high membership probabilities, and we assign them TWA numbers: TWA 45 for 2MASS J11592786-4510192 and TWA 46 for 2MASS J12354615-4115531.

  3. Advantages of traveling wave resonant antennas for fast wave heating systems

    International Nuclear Information System (INIS)

    Phelps, D.A.; Callis, R.W.; Grassie, J.S. de

    1997-04-01

    The resilience of a maximally flat externally coupled traveling wave antenna (TWA) is contrasted with the sensitivity of a simple directly driven resonant loop array to vacuum and plasma conditions in DIII-D. We find a unique synergy between standing and traveling wave resonant TWA components. This synergy extends TWA operation to several passbands between 60 and 120 MHZ, provides 60 degrees- 120 degrees tunability between elements within a 1-2 MHZ bandwidth and permits efficient and continuous operation during ELMing H-mode

  4. The traveling-wave amplifier model of the cochlea adapted to dolphins

    DEFF Research Database (Denmark)

    Andersen, Lars Nonboe; Au, W.W.L.

    1999-01-01

    The traveling-wave amplifier (TWA) model of the cochlea [A. Hubbard, Science 259, 68–71 (1993)] has been shown to produce outputs that compare quite well with experimental data. A TWA model with parameters adjusted to fit the physiological properties of the dolphin cochlea was used as part...... of a sonar signal discrimination system. The system was tested on a cylinder wall thickness discrimination problem. Broadband echoes from cylinders with different wall thicknesses were aligned using a matched filter and envelope detection. The aligned signals were used as inputs to the TWA model and energy...

  5. Periprosthetic osteolysis after total wrist arthroplasty

    DEFF Research Database (Denmark)

    Boeckstyns, Michel E H; Herzberg, Guillaume

    2014-01-01

    Background and Literature Review Periprosthetic osteolysis (PPO) after second- or third-generation total wrist arthroplasty (TWA), with or without evident loosening of the implant components, has previously been reported in the literature, but rarely in a systematic way. Purpose The purpose...... of this study was to analyze the prevalence, location, and natural history of PPO following a TWA and to determine whether this was associated with prosthetic loosening. Patients and Methods We analyzed 44 consecutive cases in which a RE-MOTION TWA (Small Bone Innovations Inc., Morrisville, PA, USA) had been...

  6. Reference values of electrocardiogram repolarization variables in a healthy population

    DEFF Research Database (Denmark)

    Haarmark, Christian; Graff, Claus; Andersen, Mads P

    2010-01-01

    Reference values for T-wave morphology analysis and evaluation of the relationship with age, sex, and heart rate are lacking in the literature. In this study, we characterized T-wave morphology in a large sample of healthy individuals....

  7. Effects of time-variable exposure regimes of the insecticide chlorpyrifos on freshwater invertebrate communities in microcosms

    NARCIS (Netherlands)

    Zafar, M.I.; Wijngaarden, van R.; Roessink, I.; Brink, van den P.J.

    2011-01-01

    The present study compared the effects of different time-variable exposure regimes having the same time-weighted average (TWA) concentration of the organophosphate insecticide chlorpyrifos on freshwater invertebrate communities to enable extrapolation of effects across exposure regimes. The

  8. Throughout Any Scale

    DEFF Research Database (Denmark)

    Munch, Anders V.

    2004-01-01

    Med udgangspunkt i principielle overvejelser af skalaer for design og tanken om at lave totaldesign eller Gesamtkunstwerk gennem alle skalaer laves et designhistorisk rids med analyse af eksempler som SAS Hotel Royal, TWA-terminalen og Odense Universitet....

  9. Long-Term Non-Invasive ECG-Based Risk Stratification of Sudden Cardiac Death: Extended 5-Year Results

    Directory of Open Access Journals (Sweden)

    Elena Okisheva

    2017-01-01

    Evaluation of HRT, DC and mTWA during 24-hour ECG monitoring may define the high risk of cardiovascular mortality and SCD in post-MI patients especially during the first 12 months after the baseline examination.

  10. A Gaia DR2 Confirmation that 2MASS J12074836–3900043 is a Member of the TW HYA Association

    Science.gov (United States)

    Gagné, Jonathan; Gonzales, Eileen C.; Faherty, Jacqueline K.

    2018-05-01

    We use new data from Gaia DR2 to confirm that the young L1 $\\gamma$ candidate member of the TW Hya association (TWA) is now a bona fide member with a model-dependent mass estimate of ~15 $M_{Jup}$. The ambiguous M9 $\\gamma$ candidate member 2MASS J12474428---3816464 also gets a higher Bayesian membership probability for TWA membership as a result of Gaia DR2 data and a new radial velocity measurement, but it remains unclear whether it is a true member of TWA or if it is an unrelated young interloper, because it is separated by 4.6 km/s from the locus of TWA members in UVW space.

  11. Ullage Compatible Optical Sensor for Monitoring Safety Significant Malfunctions, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Significant emphasis has been placed on aircraft fuel tank safety following the TWA Flight 800 accident in July 1996. Upon investigation, the National Transportation...

  12. Innovative Technologies for a bio-based economy

    International Nuclear Information System (INIS)

    2008-01-01

    This special edition of TWA Nieuws representatives of various Dutch embassies in the world pay attention to developments concerning the many-sided applications of biological products in the Netherlands, the European Union, the United Kingdom, France, Germany, Sweden, Finland, Italy, Singapore, Japan, Taiwan, China and the United States. The title of this edition refers to the conference with the same name that will be held by TWA-Netwerk on 8 April 2008 at the Dutch Wageningen University research Center. [mk] [nl

  13. The importance of hormonal circadian rhythms in daily feeding patterns

    NARCIS (Netherlands)

    Boumans, Iris J.M.M.; Boer, de Imke J.M.; Hofstede, Gert Jan; Fleur, la Susanne E.; Bokkers, Eddy

    2017-01-01

    The interaction between hormonal circadian rhythms and feeding behaviour is not well understood. This study aimed to deepen our understanding of mechanisms underlying circadian feeding behaviour in animals, using pigs, Sus scrofa, as a case study. Pigs show an alternans feeding pattern, that is,

  14. The importance of hormonal circadian rhythms in daily feeding patterns: An illustration with simulated pigs

    NARCIS (Netherlands)

    Boumans, Iris J. M. M.; de Boer, Imke J. M.; Hofstede, Gert Jan; la Fleur, Susanne E.; Bokkers, Eddie A. M.

    2017-01-01

    The interaction between hormonal circadian rhythms and feeding behaviour is not well understood. This study aimed to deepen our understanding of mechanisms underlying circadian feeding behaviour in animals, using pigs, Sus scrofa, as a case study. Pigs show an alternans feeding pattern, that is, a

  15. Liamocins, sophorolipids, and frost grape polysaccharides. New carbohydrate research from the USDA’s NCAUR national laboratory

    Science.gov (United States)

    The USDA’s National Center for Agricultural Utilization Research has a prominent history in carbohydrate research, including the development of xanthan gum, ‘super slurper’ polysaccharides, beta-dextrans, alternan, and beta lactamase antibiotics (penicillins), as well as analytical tools such as ald...

  16. New records of Scenedesmus Meyen from China

    Directory of Open Access Journals (Sweden)

    ZHU Yaru

    2012-08-01

    Full Text Available One species,four variant and one forma of Chlorophyta Scenedesmus are first reported in China,they are Scenedesmus ecornis var.disciformis,S.acutus f.alternans,S.ginzbergeri,S.intermedius var. bicaudatus,S.opoliensis var. polycostatus and S.opoliensis var.bicaudatus.The taxonomic characters were described for each taxon by micro-photography and pictures.

  17. Glucan synthesis in the genus Lactobacillus: Isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains

    NARCIS (Netherlands)

    Kralj, S.; Geel-Schutten, G.H. van; Dondorff, M.M.G.; Kirsanovs, S.; Maarel, M.J.E.C. van der; Dijkhuizen, L.

    2004-01-01

    Members of the genera Streptococcus and Leuconostoc synthesize various α-glucans (dextran, alternan and mutan). In Lactobacillus, until now, the only glucosyltransferase (GTF) enzyme that has been characterized is gtfA of Lactobacillus reuteri 121, the first GTF enzyme synthesizing a glucan

  18. Glucan synthesis in the genus Lactobacillus : isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains

    NARCIS (Netherlands)

    Kralj, S.; Geel-Schutten, G.H. van; Dondorff, M.M.G.; Kirsanovs, S.; Maarel, M.J.E.C. van der; Dijkhuizen, L.

    2004-01-01

    Members of the genera Streptococcus and Leuconostoc synthesize various α-glucans (dextran, alternan and mutan). In Lactobacillus, until now, the only glucosyltransferase (GTF) enzyme that has been characterized is gtfA of Lactobacillus reuteri 121, the first GTF enzyme synthesizing a glucan

  19. BANYAN. IX. The Initial Mass Function and Planetary-mass Object Space Density of the TW HYA Association

    Science.gov (United States)

    Gagné, Jonathan; Faherty, Jacqueline K.; Mamajek, Eric E.; Malo, Lison; Doyon, René; Filippazzo, Joseph C.; Weinberger, Alycia J.; Donaldson, Jessica K.; Lépine, Sébastien; Lafrenière, David; Artigau, Étienne; Burgasser, Adam J.; Looper, Dagny; Boucher, Anne; Beletsky, Yuri; Camnasio, Sara; Brunette, Charles; Arboit, Geneviève

    2017-02-01

    A determination of the initial mass function (IMF) of the current, incomplete census of the 10 Myr-old TW Hya association (TWA) is presented. This census is built from a literature compilation supplemented with new spectra and 17 new radial velocities from ongoing membership surveys, as well as a reanalysis of Hipparcos data that confirmed HR 4334 (A2 Vn) as a member. Although the dominant uncertainty in the IMF remains census incompleteness, a detailed statistical treatment is carried out to make the IMF determination independent of binning while accounting for small number statistics. The currently known high-likelihood members are fitted by a log-normal distribution with a central mass of {0.21}-0.06+0.11 M ⊙ and a characteristic width of {0.8}-0.1+0.2 dex in the 12 M Jup-2 M ⊙ range, whereas a Salpeter power law with α ={2.2}-0.5+1.1 best describes the IMF slope in the 0.1-2 M ⊙ range. This characteristic width is higher than other young associations, which may be due to incompleteness in the current census of low-mass TWA stars. A tentative overpopulation of isolated planetary-mass members similar to 2MASS J11472421-2040204 and 2MASS J11193254-1137466 is identified: this indicates that there might be as many as {10}-5+13 similar members of TWA with hot-start model-dependent masses estimated at ˜5-7 M Jup, most of which would be too faint to be detected in 2MASS. Our new radial velocity measurements corroborate the membership of 2MASS J11472421-2040204, and secure TWA 28 (M8.5 γ), TWA 29 (M9.5 γ), and TWA 33 (M4.5 e) as members. The discovery of 2MASS J09553336-0208403, a young L7-type interloper unrelated to TWA, is also presented.

  20. Compact Single-Layer Traveling-Wave Antenna DesignUsing Metamaterial Transmission Lines

    Science.gov (United States)

    Alibakhshikenari, Mohammad; Virdee, Bal Singh; Limiti, Ernesto

    2017-12-01

    This paper presents a single-layer traveling-wave antenna (TWA) that is based on composite right/left-handed (CRLH)-metamaterial (MTM) transmission line (TL) structure, which is implemented by using a combination of interdigital capacitors and dual-spiral inductive slots. By embedding dual-spiral inductive slots inside the CRLH MTM-TL results in a compact TWA. Dimensions of the proposed CRLH MTM-TL TWA is 21.5 × 30.0 mm2 or 0.372λ0 × 0.520λ0 at 5.2 GHz (center frequency). The fabricated TWA operates over 1.8-8.6 GHz with a fractional bandwidth greater than 120%, and it exhibits a peak gain and radiation efficiency of 4.2 dBi and 81%, respectively, at 5 GHz. By avoiding the use of lumped components, via-holes or defected ground structures, the proposed TWA design is economic for mass production as well as easy to integrate with wireless communication systems.

  1. Sex-specific positive and negative consequences of avoidance training during childhood on adult active avoidance learning in mice

    Directory of Open Access Journals (Sweden)

    Almuth eSpröwitz

    2013-10-01

    Full Text Available In humans and animals cognitive training during childhood plays an important role in shaping neural circuits and thereby determines learning capacity later in life. Using a negative feedback learning paradigm, the two-way active avoidance (TWA learning, we aimed to investigate in mice (i the age-dependency of TWA learning, (ii the consequences of pretraining in childhood on adult learning capacity and (iii the impact of sex on the learning paradigm in mice. Taken together, we show here for the first time that the beneficial or detrimental outcome of pretraining in childhood depends on the age during which TWA training is encountered, indicating that different, age-dependent long-term memory traces might be formed, which are recruited during adult TWA training and thereby either facilitate or impair adult TWA learning. While pretraining during infancy results in learning impairment in adulthood, pretraining in late adolescence improved avoidance learning.The experiments revealed a clear sex difference in the group of late-adolescent mice: female mice showed better avoidance learning during late adolescence compared to males, and the beneficial impact of late-adolescent pretraining on adult learning was more pronounced in females compared to males.

  2. IDENTIFYING NEARBY, YOUNG, LATE-TYPE STARS BY MEANS OF THEIR CIRCUMSTELLAR DISKS

    International Nuclear Information System (INIS)

    Schneider, Adam; Song, Inseok; Melis, Carl; Zuckerman, B.; Bessell, Mike

    2012-01-01

    It has recently been shown that a significant fraction of late-type members of nearby, very young associations (age ∼<10 Myr) display excess emission at mid-IR wavelengths indicative of dusty circumstellar disks. We demonstrate that the detection of mid-IR excess emission can be utilized to identify new nearby, young, late-type stars including two definite new members ('TWA 33' and 'TWA 34') of the TW Hydrae Association (TWA). Both new TWA members display mid-IR excess emission in the Wide-field Infrared Survey Explorer catalog and they show proper motion and youthful spectroscopic characteristics—namely, Hα emission, strong lithium absorption, and low surface gravity features consistent with known TWA members. We also detect mid-IR excess—the first unambiguous evidence of a dusty circumstellar disk—around a previously identified UV-bright, young, accreting star (2M1337) that is a likely member of the Lower-Centaurus Crux region of the Scorpius-Centaurus Complex.

  3. Ku-Band Traveling Wave Slot Array Using Simple Scanning Control

    Science.gov (United States)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda, Felix A.

    2015-01-01

    This paper introduces a feeding concept aimed at simplifying the backend (phase shifters) of traditional phased arrays. As an alternative to traditional phased arrays, we employ a traveling wave array (TWA) using a single feedline whose propagation constant is controlled via a single, small mechanical movement without a need for phase shifters to enable scanning. Specifically, a dielectric plunger is positioned within a parallel plate waveguide (PPW) transmission line (TL) that feeds the TWA. By adjusting the position of the dielectric plunger within the PPW feeding the TWA, beam steering is achieved. A 20 element array is designed at 13GHz shown to give stable realized gain across the angular range of -25 deg. less than or equal to theta less than or equal to 25 deg. A proof of concept array is fabricated and measured to demonstrate and validate the concept's operation.

  4. Broadband Amplification of Low-Terahertz Signals Using Axis-Encircling Electrons in a Helically Corrugated Interaction Region

    Science.gov (United States)

    He, W.; Donaldson, C. R.; Zhang, L.; Ronald, K.; Phelps, A. D. R.; Cross, A. W.

    2017-11-01

    Experimental results are presented of a broadband, high power, gyrotron traveling wave amplifier (gyro-TWA) operating in the (75-110)-GHz frequency band and based on a helically corrugated interaction region. The second harmonic cyclotron mode of a 55-keV, 1.5-A, axis-encircling electron beam is used to resonantly interact with a traveling TE21 -like eigenwave achieving broadband amplification. The gyro-TWA demonstrates a 3-dB gain bandwidth of at least 5.5 GHz in the experimental measurement with 9 GHz predicted for a wideband drive source with a measured unsaturated output power of 3.4 kW and gain of 36-38 dB. The approach may allow a gyro-TWA to operate at 1 THz.

  5. Extremely Low Frequency-Magnetic Fields (ELF-EMF) occupational exposure and natural killer activity in peripheral blood lymphocytes

    International Nuclear Information System (INIS)

    Gobba, Fabriziomaria; Bargellini, Annalisa; Scaringi, Meri; Bravo, Giulia; Borella, Paola

    2009-01-01

    Extremely Low Frequency-Magnetic Fields (ELF-MF) are possible carcinogens to humans and some data suggest that they can act as promoters or progressors. Since NK cells play a major role in the control of cancer development, an adverse effect on ELF-MF on NK function has been hypothesized. We examined NK activity in 52 workers exposed to different levels of ELF-MF in various activities. Individual exposure was monitored during 3 complete work-shifts using personal dosimeters. Environmental exposure was also monitored. ELF-MF levels in the workers were expressed as Time-Weighted Average (TWA) values. NK activity was measured in peripheral blood lymphocytes (PBL). In the whole group the median occupational TWA was 0.21 μT. According to the TWA levels, workers were classified as low exposed (26 subjects, TWA ≤ 0.2 μT) and higher exposed workers (26 subjects; TWA > 0.2 μT). In higher exposed workers, we observed a trend to reduce NK activity compared to low exposed, but the difference was not significant. Then we selected a subgroup of highest exposed workers (12 subjects; TWA > 1 μT); no difference was observed between low and highest exposed subjects in the main personal variables. Considering both E:T ratios from 12:1 to 50:1 and Lytic Units, a significant reduction in NK activity was observed in the highest exposed workers compared to the low exposed. Multivariate analysis showed a significant negative correlation between exposure and LU, while no correlation was evidenced with other personal characteristics. ELF-MF are considered possible carcinogens, and existing data suggest that they can act as promoters. Due to the role of NK activity in host defence against cancer, the results obtained in this study in workers exposed to ELF-MF levels exceeding 1 μT are in agreement with this hypothesis, and support the need for further investigation in this field

  6. Social Cognitive Career Theory, the Theory of Work Adjustment, and Work Satisfaction of Retirement-Age Adults.

    Science.gov (United States)

    Foley, Pamela F; Lytle, Megan C

    2015-06-01

    Despite a recent increase in the number of adults who work past traditional retirement age, existing theories of vocational behavior have not yet received adequate empirical support. In a large sample of adults age 60-87, we evaluated the relationship between theorized predictors of work satisfaction proposed by Social Cognitive Career Theory (SCCT), work satisfaction as a predictor of continued work, as proposed by the Theory of Work adjustment (TWA), as well as the influence of reported experiences of discrimination on these relationships. While the results supported most of the predicted relationships, the effects of discrimination were stronger than the variables proposed by either SCCT or TWA for the present sample.

  7. Orchids inventory in Sintang Regency, West Kalimantan

    Directory of Open Access Journals (Sweden)

    ESTI ENDAH ARIYANTI

    2008-10-01

    Full Text Available Orchid is one of ornamental plants which have commercial value. Therefore most species are becoming threatened or even endangered because of over exploitation. In addition, its natural habitat is also decreasing. Conservation must be done urgently, both by in situ and ex situ conservation, which can be started by orchid inventory. The orchid inventory was done in TWA Bukit Kelam, TWA Baning and several places in Regency of Sintang, West Kalimantan. The result showed that there were 40 species belonged to 27 genera, which 32 species of them (20 genera were epiphytic orchids and 8 species (7 genera were terrestrial orchids.

  8. Rehabilitation R&D Progress Reports 1996, Volume 34, May 1997

    Science.gov (United States)

    1997-05-01

    Arlington, VA 22230 PURPOSE!—Atrioventricular (AV) nodal alternans is a pathological cardiac condition characterized by a beat - to- beat alternation...regime where the AV nodal conduc- tion time alternated on a beat -to- beat basis. After using additive white noise to learn the dynamics of the underly... binaurally accord- ing to the NAL-R prescriptive formula. These groups will be followed over a period of 6 months and tested at monthly intervals. At each

  9. Paradoxical effects of KB-R7943 on arrhythmogenicity in a chronic myocardial infarction rabbit model.

    Science.gov (United States)

    Chang, Po-Cheng; Wo, Hung-Ta; Lee, Hui-Ling; Wen, Ming-Shien; Chou, Chung-Chuan

    2015-07-01

    Na(+)/Ca(2+) exchanger blockade has been reported to be anti-arrhythmic in different models. The effects of KB-R7943, a Na(+)/Ca(2+) exchanger blocker, on arrhythmogenesis in hearts with chronic myocardial infarction (MI) remain unclear. Dual voltage and intracellular Ca(2+) (Cai) optical mapping was performed in nine rabbit hearts with chronic MI and four control hearts. Electrophysiology studies including inducibility of ventricular tachyarrhythmias, ventricular fibrillation dominant frequency, action potential, Cai alternans, Cai decay, and conduction velocity were performed. The same protocol was repeated in the presence of KB-R7943 (0.5, 1, and 5μM) after the baseline studies. KB-R7943 was effective in suppressing afterdepolarizations and spontaneous ventricular tachyarrhythmias in hearts with chronic MI. Surprisingly, KB-R7943 increased the inducibility of ventricular tachyarrhythmias in a dose-dependent manner (11%, 11%, 22%, and 56% at baseline and with 0.5, 1, and 5μM KB-R7943, respectively, p=0.02). Optical mapping analysis revealed that the underlying mechanisms of the induced ventricular tachyarrhythmias were probably spatially discordant alternans with wave breaks and rotors. Further analysis showed that KB-R7943 significantly enhanced both action potential (p=0.033) and Cai (p=0.001) alternans, prolonged Cai decay (tau value) in a dose-dependent manner (p=0.004), and caused heterogeneous conduction delay especially at peri-infarct zones during rapid burst pacing. In contrast, KB-R7943 had insignificant effects in control hearts. In this chronic MI rabbit model, KB-R7943 has contrasting effects on arrhythmogenesis, suppressing afterdepolarizations and spontaneous ventricular tachyarrhythmias, but enhancing the inducibility of tachyarrhythmias. The mechanism is probably the enhanced spatially discordant alternans because of prolonged Cai decay and heterogeneous conduction delay. Copyright © 2014 Japanese College of Cardiology. Published by Elsevier

  10. Heart rate variability alters cardiac repolarization and electromechanical dynamics.

    Science.gov (United States)

    Phadumdeo, Vrishti M; Weinberg, Seth H

    2018-04-07

    Heart rate continuously varies due to autonomic regulation, stochasticity in pacemaking, and circadian rhythm, collectively termed heart rate variability (HRV), during normal physiological conditions. Low HRV is clinically associated with an elevated risk of cardiac arrhythmias. Alternans, a beat-to-beat alternation in action potential duration (APD) and/or intracellular calcium (Ca) transient, is a well-known risk factor associated with cardiac arrhythmias that is typically studied under conditions of a constant pacing rate, i.e., the absence of HRV. In this study, we investigate the effects of HRV on the interplay between APD, Ca, and electromechanical properties, employing a nonlinear discrete-time map model that governs APD and intracellular Ca cycling with a stochastic pacing period. We find that HRV can decrease variation in APD and peak Ca at fast pacing rates for which alternans is present. Further, increased HRV typically disrupts the alternating pattern for both APD and peak Ca and weakens the correlation between APD and peak Ca, thus decoupling Ca-mediated instabilities from repolarization alternation. We find that the efficacy of these effects is regulated by the sarcoplasmic reticulum Ca uptake rate. Overall, these results demonstrate that HRV disrupts arrhythmogenic alternans and suggests that HRV may be a significant factor in preventing life-threatening arrhythmias. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Repolarization gradients in the canine left ventricle before and after induction of short-term cardiac memory

    NARCIS (Netherlands)

    Janse, Michiel J.; Sosunov, Eugene A.; Coronel, Ruben; Opthof, Tobias; Anyukhovsky, Evgeny P.; de Bakker, Jacques M. T.; Plotnikov, Alexei N.; Shlapakova, Iryna N.; Danilo, Peter; Tijssen, Jan G. P.; Rosen, Michael R.

    2005-01-01

    Background - Questions remain about the contributions of transmural versus apicobasal repolarization gradients to the configuration of the T wave in control settings and after the induction of short-term cardiac memory. Methods and Results - Short-term cardiac memory is seen as T-wave changes

  12. Traveling-wave ion mobility mass spectrometry of protein complexes

    DEFF Research Database (Denmark)

    Salbo, Rune; Bush, Matthew F; Naver, Helle

    2012-01-01

    The collision cross-section (Ω) of a protein or protein complex ion can be measured using traveling-wave (T-wave) ion mobility (IM) mass spectrometry (MS) via calibration with compounds of known Ω. The T-wave Ω-values depend strongly on instrument parameters and calibrant selection. Optimization ...

  13. Career decision-making of the gifted and talented

    African Journals Online (AJOL)

    eleven gifted and talented high school students, studying in congregative gifted ... that all students have supports and guidance to promote successful ... The career or vocational counselling issues most discussed in the broader ... They suggest that the Theory of Work Adjustment (TWA; Dawis & ..... International handbook of.

  14. 33 CFR 149.697 - What are the requirements for a noise level survey?

    Science.gov (United States)

    2010-07-01

    ... and Equipment Noise Limits § 149.697 What are the requirements for a noise level survey? (a) A survey... measured over 12 hours to derive a time weighted average (TWA) using a sound level meter and an A-weighted filter or equivalent device. (c) If the noise level throughout a space is determined to exceed 85 db(A...

  15. 78 FR 59633 - Wireless Telecommunications Bureau Opens Docket To Seek Comment on DISH Network Corporation's...

    Science.gov (United States)

    2013-09-27

    ... 9, 2013, the DISH Network Corporation, on behalf of its wholly-owned subsidiaries, Gamma Acquisition... held by its wholly-owned subsidiaries, Gamma Acquisition LLC (Call Signs T060430001-T060430176) and New... Commission's Secretary must be delivered to FCC Headquarters at 445 12th Street SW., Room TW-A325, Washington...

  16. Teachers' Autonomy in Today's Educational Climate: Current Perceptions from an Acceptable Instrument

    Science.gov (United States)

    Strong, Luman E. G.; Yoshida, Roland K.

    2014-01-01

    This research evaluated the psychometric properties of Friedman's (1999) Teacher Work-Autonomy Scale (TWA) to determine whether it was an acceptable instrument to measure U.S. teacher autonomy in the present educational context. A second purpose was to ascertain the current status of teachers' perceptions of their autonomy from a sample of U.S.…

  17. Validation of Passive Sampling Devices for Monitoring of Munitions Constituents in Underwater Environments

    Science.gov (United States)

    2017-06-30

    Research and Development Program [SERDP] project #ER-2542) into the canister would provide enhancement of the quantitative estimation of the TWA...Department of Defense EOD Explosive Ordnance Disposal EPA United States Environmental Protection Agency EQL Environmental Quantitation Limit EST...Laboratory Quantitation Limit MC Munitions Constituents mL Milliliter MR Munitions Response NESDI Navy’s Environmental Security Development to

  18. Relationships Among Non-Invasive Predictors of Sudden Cardiac Death During Mental Stress and Exercise In Coronary Artery Disease Patients With Known Arrhythmic Vulnerability

    Science.gov (United States)

    2009-12-16

    been linked to visceral obesity , hypertension, hyperlipidemia, and insulin resistance (Hautanen & Adlercreutz, 1993; Rosmond & Bjorntorp, 1998...Kovach and Nearing (2001) found that induction of anger in canines resulted in TWA increases with or without myocardial ischemia. However, other...77. Bjorntorp, P. (1997). Obesity . Lancet, 350(9075), 423-426. Bloomfield, D. M., Kaufman, E. S., Bigger, J. T., Jr., Fleiss, J., Rolnitzky, L

  19. Workplace Support, Discrimination, and Person-Organization Fit: Tests of the Theory of Work Adjustment with LGB Individuals

    Science.gov (United States)

    Velez, Brandon L.; Moradi, Bonnie

    2012-01-01

    The present study explored the links of 2 workplace contextual variables--perceptions of workplace heterosexist discrimination and lesbian, gay, and bisexual (LGB)-supportive climates--with job satisfaction and turnover intentions in a sample of LGB employees. An extension of the theory of work adjustment (TWA) was used as the conceptual framework…

  20. 75 FR 51812 - The Consumer and Governmental Affairs Bureau Seeks Comment on the Commission's Policies and...

    Science.gov (United States)

    2010-08-23

    ... technology and achievability, and that it update its Section 504 Handbook every three years. The Section 504 Handbook contains accessibility procedures and guidelines for releasing documents, holding meetings... TW-A325, Washington, DC 20554. All hand deliveries must be held together with rubber bands or...

  1. Hangar con alas, Los Angeles

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1961-04-01

    Full Text Available Formando parte de su programa, la TWA ha construido recientemente un hangar para servicio y reparaciones de su flota aérea de naves ordinarias y de aviones de reacción en el aeropuerto internacional de Los Angeles (Estados Unidos. El proyecto de esta obra se encargó a la empresa constructora Holmes & Narver, Inc.

  2. DISTANCE AND KINEMATICS OF THE TW HYDRAE ASSOCIATION FROM PARALLAXES

    Energy Technology Data Exchange (ETDEWEB)

    Weinberger, Alycia J.; Boss, Alan P. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Anglada-Escude, Guillem, E-mail: weinberger@dtm.ciw.edu [Institut fuer Astrophysik, Universitaet Goettingen, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany)

    2013-01-10

    From common proper motion and signatures of youth, researchers have identified about 30 members of a putative TW Hydrae Association. Only four of these had parallactic distances from Hipparcos. We have measured parallaxes and proper motions for 14 primary members. We combine these with literature values of radial velocities to show that the Galactic space motions of the stars, with the exception of TWA 9 and 22, are parallel and do not indicate convergence at a common formation point sometime in the last few million years. The space motions of TWA 9 and 22 do not agree with the others and indicate that they are not TWA members. The median parallax is 18 mas or 56 pc. We further analyze the stars' absolute magnitudes on pre-main-sequence evolutionary tracks and find a range of ages with a median of 10.1 Myr and no correlation between age and Galactic location. The TWA stars may have formed from an extended and filamentary molecular cloud but are not necessarily precisely coeval.

  3. Nonequilibrium dynamics of spin-boson models from phase-space methods

    Science.gov (United States)

    Piñeiro Orioli, Asier; Safavi-Naini, Arghavan; Wall, Michael L.; Rey, Ana Maria

    2017-09-01

    An accurate description of the nonequilibrium dynamics of systems with coupled spin and bosonic degrees of freedom remains theoretically challenging, especially for large system sizes and in higher than one dimension. Phase-space methods such as the truncated Wigner approximation (TWA) have the advantage of being easily scalable and applicable to arbitrary dimensions. In this work we adapt the TWA to generic spin-boson models by making use of recently developed algorithms for discrete phase spaces [J. Schachenmayer, A. Pikovski, and A. M. Rey, Phys. Rev. X 5, 011022 (2015), 10.1103/PhysRevX.5.011022]. Furthermore we go beyond the standard TWA approximation by applying a scheme based on the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy of equations to our coupled spin-boson model. This allows us, in principle, to study how systematically adding higher-order corrections improves the convergence of the method. To test various levels of approximation we study an exactly solvable spin-boson model, which is particularly relevant for trapped-ion arrays. Using TWA and its BBGKY extension we accurately reproduce the time evolution of a number of one- and two-point correlation functions in several dimensions and for an arbitrary number of bosonic modes.

  4. Understanding the spiral structure of the Milky Way using the local kinematic groups

    NARCIS (Netherlands)

    Antoja Castelltort, Teresa; Figueras, F.; Romero-Gomez, M.; Pichardo, B.; Valenzuela, O.; Moreno, E.

    2011-01-01

    We study the spiral arm influence on the solar neighbourhood stellar kinematics. As the nature of the Milky Way (MW) spiral arms is not completely determined, we study two models: the Tight-Winding Approximation (TWA) model, which represents a local approximation, and a model with self-consistent

  5. Low-order-mode harmonic multiplying gyrotron traveling-wave amplifier in W band

    International Nuclear Information System (INIS)

    Yeh, Y. S.; Chen, C. H.; Yang, S. J.; Lai, C. H.; Lin, T. Y.; Lo, Y. C.; Hong, J. W.; Hung, C. L.; Chang, T. H.

    2012-01-01

    Harmonic multiplying gyrotron traveling-wave amplifiers (gyro-TWAs) allow for magnetic field reduction and frequency multiplication. To avoid absolute instabilities, this work proposes a W-band harmonic multiplying gyro-TWA operating at low-order modes. By amplifying a fundamental harmonic TE 11 drive wave, the second harmonic component of the beam current initiates a TE 21 wave to be amplified. Absolute instabilities in the gyro-TWA are suppressed by shortening the interaction circuit and increasing wall losses. Simulation results reveal that compared with Ka-band gyro-TWTs, the lower wall losses effectively suppress absolute instabilities in the W-band gyro-TWA. However, a global reflective oscillation occurs as the wall losses decrease. Increasing the length or resistivity of the lossy section can reduce the feedback of the oscillation to stabilize the amplifier. The W-band harmonic multiplying gyro-TWA is predicted to yield a peak output power of 111 kW at 98 GHz with an efficiency of 25%, a saturated gain of 26 dB, and a bandwidth of 1.6 GHz for a 60 kV, 7.5 A electron beam with an axial velocity spread of 8%.

  6. Formaldehyde exposure in U.S. industries from OSHA air sampling data.

    Science.gov (United States)

    Lavoue, Jerome; Vincent, Raymond; Gerin, Michel

    2008-09-01

    National occupational exposure databanks have been cited as sources of exposure data for exposure surveillance and exposure assessment for occupational epidemiology. Formaldehyde exposure data recorded in the U.S Integrated Management Information System (IMIS) between 1979 and 2001 were collected to elaborate a multi-industry retrospective picture of formaldehyde exposures and to identify exposure determinants. Due to the database design, only detected personal measurement results (n = 5228) were analyzed with linear mixed-effect models, which explained 29% of the total variance. Short-term measurement results were higher than time-weighted average (TWA) data and decreased 18% per year until 1987 (TWA data 5% per year) and 5% per year (TWA data 4% per year) after that. Exposure varied across industries with maximal estimated TWA geometric means (GM) for 2001 in the reconstituted wood products, structural wood members, and wood dimension and flooring industries (GM = 0.20 mg/m(3). Highest short-term GMs estimated for 2001 were in the funeral service and crematory and reconstituted wood products industries (GM = 0.35 mg/m(3). Exposure levels in IMIS were marginally higher during nonprogrammed inspections compared with programmed inspections. An increasing exterior temperature tended to cause a decrease in exposure levels for cold temperatures (-5% per 5 degrees C for T 15 degrees C). Concentrations measured during the same inspection were correlated and varied differently across industries and sample type (TWA, short term). Sensitivity analyses using TOBIT regression suggested that the average bias caused by excluding non-detects is approximately 30%, being potentially higher for short-term data if many non-detects were actually short-term measurements. Although limited by availability of relevant exposure determinants and potential selection biases in IMIS, these results provide useful insight on formaldehyde occupational exposure in the United States in the last

  7. Effectiveness evaluation of existing noise controls in a deep shaft underground mine.

    Science.gov (United States)

    Lutz, Eric A; Reed, Rustin J; Turner, Dylan; Littau, Sally R; Lee, Vivien; Hu, Chengcheng

    2015-01-01

    Noise exposures and hearing loss in the mining industry continue to be a major problem, despite advances in noise control technologies. This study evaluated the effectiveness of engineering, administrative, and personal noise controls using both traditional and in-ear dosimetry by job task, work shift, and five types of earplug. The noise exposures of 22 miners performing deep shaft-sinking tasks were evaluated during 56 rotating shifts in an underground mine. Miners were earplug-insertion trained, earplug fit-tested, and monitored utilizing traditional and in-ear dosimetry. The mean TWA8 noise exposure via traditional dosimetry was 90.1 ± 8.2 dBA, while the mean in-ear TWA8 was 79.6 ± 13.8 dBA. The latter was significantly lower (p < 0.05) than the Mine Safety and Health Administration (MSHA) personal exposure limit (PEL) of 90 dBA. Dosimetry mean TWA8 noise exposures for bench blowing (103.5 ± 0.9 dBA), jumbo drill operation (103.0 ± 0.8 dBA), and mucking tasks (99.6 ± 4.7 dBA) were significantly higher (p < 0.05) than other tasks. For bench blowing, cable pulling, grinding, and jumbo drill operation tasks, the mean in-ear TWA8 was greater than 85 dBA. Those working swing shift had a significantly higher (p < 0.001) mean TWA8 noise exposure (95.4 ± 7.3 dBA) than those working day shift. For percent difference between traditional vs. in-ear dosimetry, there was no significant difference among types of earplug used. Reflective of occupational hearing loss rate trends across the mining industry, this study found that, despite existing engineering and administrative controls, noise exposure levels exceeded regulatory limits, while the addition of personal hearing protection limited excessive exposures.

  8. Temporal and Other Exposure Aspects of Residential Magnetic Fields Measurement in Relation to Acute Lymphoblastic Leukaemia in Children: The National Cancer Institute Children's Cancer Group Study (invited paper)

    International Nuclear Information System (INIS)

    Baris, D.; Linet, M.; Auvinen, A.; Kaune, W.T.; Wacholder, S.; Kleinerman, R.; Hatch, E.; Robison, L.; Niwa, S.; Haines, C.; Tarone, R.E.

    1999-01-01

    Case-control studies have used a variety of measurements to evaluate the relationship of children's exposure to magnetic fields (50 or 60 Hz) with childhood leukaemia and other childhood cancers. In the absence of knowledge about which exposure metrics may be biologically meaningful, studies during the past 10 years have often used time-weighted average (TWA) summaries of home measurements. Recently, other exposure metrics have been suggested, usually based on theoretical considerations or limited laboratory data. In this paper, the rationale and associated preliminary studies undertaken are described as well as feasibility and validity issues governing the choice of the primary magnetic field exposure assessment methods and summary metric used to estimate children's exposure in the National Cancer Institute/Children's Cancer Group (NCI/CCG) case-control study. Also provided are definitions and discussion of the strengths and weaknesses of the various exposure metrics used in exploratory analyses of the NCI/CCG measurement data. Exposure metrics evaluated include measures of central tendency (mean, median, 30th to 70th percentiles), peak exposures (90th and higher percentiles, peak values of the 24 h measurements), and measurements of short-term temporal variability (rate of change). This report describes correlations of the various metrics with the time-weighted average for the 24 h period (TWA-24-h). Most of the metrics were found to be positively and highly correlated with TWA-24-h, but lower correlations of TWA-24-h with peak exposure and with rate of change were observed. To examine further the relation between TWA and alternative metrics, similar exploratory analysis should be considered for existing data sets and for forthcoming measurement investigations of residential magnetic fields and childhood leukaemia. (author)

  9. Temporal and Other Exposure Aspects of Residential Magnetic Fields Measurement in Relation to Acute Lymphoblastic Leukaemia in Children: The National Cancer Institute Children's Cancer Group Study (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    Baris, D.; Linet, M.; Auvinen, A.; Kaune, W.T.; Wacholder, S.; Kleinerman, R.; Hatch, E.; Robison, L.; Niwa, S.; Haines, C.; Tarone, R.E

    1999-07-01

    Case-control studies have used a variety of measurements to evaluate the relationship of children's exposure to magnetic fields (50 or 60 Hz) with childhood leukaemia and other childhood cancers. In the absence of knowledge about which exposure metrics may be biologically meaningful, studies during the past 10 years have often used time-weighted average (TWA) summaries of home measurements. Recently, other exposure metrics have been suggested, usually based on theoretical considerations or limited laboratory data. In this paper, the rationale and associated preliminary studies undertaken are described as well as feasibility andvalidity issues governing the choice of the primary magnetic field exposure assessment methods and summary metric used to estimate children's exposure in the National Cancer Institute/Children's Cancer Group (NCI/CCG) case-control study. Also provided are definitions and discussion of the strengths and weaknesses of the various exposure metrics used in exploratory analyses of the NCI/CCG measurement data. Exposure metrics evaluated include measures of central tendency (mean, median, 30th to 70th percentiles), peak exposures (90th and higher percentiles, peak values of the 24 h measurements), and measurements of short-term temporal variability (rate of change). This report describes correlations of the various metrics with the time-weighted average for the 24 h period (TWA-24-h). Most of the metrics were found to be positively and highly correlated with TWA-24-h, but lower correlations of TWA-24-h with peak exposure and with rate of change were observed. To examine further the relation between TWA and alternative metrics, similar exploratory analysis should be considered for existing data sets and for forthcoming measurement investigations of residential magnetic fields and childhood leukaemia. (author)

  10. Risk assessments using the Strain Index and the TLV for HAL, Part I: Task and multi-task job exposure classifications.

    Science.gov (United States)

    Kapellusch, Jay M; Bao, Stephen S; Silverstein, Barbara A; Merryweather, Andrew S; Thiese, Mathew S; Hegmann, Kurt T; Garg, Arun

    2017-12-01

    The Strain Index (SI) and the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value for Hand Activity Level (TLV for HAL) use different constituent variables to quantify task physical exposures. Similarly, time-weighted-average (TWA), Peak, and Typical exposure techniques to quantify physical exposure from multi-task jobs make different assumptions about each task's contribution to the whole job exposure. Thus, task and job physical exposure classifications differ depending upon which model and technique are used for quantification. This study examines exposure classification agreement, disagreement, correlation, and magnitude of classification differences between these models and techniques. Data from 710 multi-task job workers performing 3,647 tasks were analyzed using the SI and TLV for HAL models, as well as with the TWA, Typical and Peak job exposure techniques. Physical exposures were classified as low, medium, and high using each model's recommended, or a priori limits. Exposure classification agreement and disagreement between models (SI, TLV for HAL) and between job exposure techniques (TWA, Typical, Peak) were described and analyzed. Regardless of technique, the SI classified more tasks as high exposure than the TLV for HAL, and the TLV for HAL classified more tasks as low exposure. The models agreed on 48.5% of task classifications (kappa = 0.28) with 15.5% of disagreement between low and high exposure categories. Between-technique (i.e., TWA, Typical, Peak) agreement ranged from 61-93% (kappa: 0.16-0.92) depending on whether the SI or TLV for HAL was used. There was disagreement between the SI and TLV for HAL and between the TWA, Typical and Peak techniques. Disagreement creates uncertainty for job design, job analysis, risk assessments, and developing interventions. Task exposure classifications from the SI and TLV for HAL might complement each other. However, TWA, Typical, and Peak job exposure techniques all have

  11. Cardiac troponin T: A sensitive and specific indicator of myocardial injury in patients with cerebrovascular stroke

    Directory of Open Access Journals (Sweden)

    Mohammed Amin

    2012-09-01

    Conclusions: Myocardial injury is not uncommon in patients with CVS. Silent ST-T wave changes and new resting SWMA are possible complications. We demonstrated highly significant correlation between positive troponin T and myocardial injury in these patients.

  12. Seminario internacional “neurociencias y la investigación del sueño” productividad y desempeño en todas las especies animales asociada al sueño volumen

    OpenAIRE

    Rojas, Manuel

    2010-01-01

    Las neurociencias agrupan un amplio espectro de tópicos de investigación en aéreas básicas y clínicas. El estudio del sistema nervioso ha aportado en las últimas décadas información trascendental que permite a la ciencia entender algunos de los circuitos, mecanismos y funciones neuronales que regulan, modulan e inducen diferentes estados de sueño. En los mamíferos es absolutamente evidente la presencia de ciclos que alternan estados de vigilia y de sueño, tanto así que la mayoría de estas esp...

  13. Anatomical basis of sleep

    OpenAIRE

    Velayos, J.L. (José Luis); Moleres, F.J. (Francisco J.); Irujo, A. (A.); Yllanes, D. (D.); Paternain, B. (B.)

    2007-01-01

    El sueño es un estado biológico activo, periódico, en el que se distinguen las etapas NREM y REM, que se alternan sucesivamente durante la noche. Intervienen los relojes biológicos en la modulación del sistema, así como neurotransmisores específicos. Se trata de una red neuronal compleja, en la que intervienen diversas zonas del sistema nervioso central. Los procesos oníricos están controlados además de forma neural. Se resume la historia de las investigaciones sobre ...

  14. Anatomical basis of sleep

    OpenAIRE

    Velayos, J. L.; Moleres, F. J.; Irujo, A. M.; Yllanes, D.; Paternain, B.

    2007-01-01

    El sueño es un estado biológico activo, periódico, en el que se distinguen las etapas NREM y REM, que se alternan sucesivamente durante la noche. Intervienen los relojes biológicos en la modulación del sistema, así como neurotransmisores específicos. Se trata de una red neuronal compleja, en la que intervienen diversas zonas del sistema nervioso central. Los procesos oníricos están controlados además de forma neural. Se resume la historia de las investigaciones sobre el tema, desde el siglo X...

  15. Implantación del TPM en líneas semiautomáticas de motores eléctricos para la industria automovilística

    OpenAIRE

    Viñolo Serrano, Jorge

    2004-01-01

    El Proyecto final de carrera que desarrollo en el grupo Bosch, por medio del programa “Educació en Alternança” está encaminado a implantar el sistema o filosofía TPM (Mantenimiento Productivo Total) en unas líneas de producción de motores eléctricos para la industria automovilística, partiendo de un sistema de producción y mantenimiento “tradicional”, queriendo obtener finalmente un sistema tanto de producción como de mantenimiento “moderno”. El fin de implantar dicho sistema es, en primer lu...

  16. Variant (Prinzmetal's) Form of Angina Pectoris Manifesting in ...

    African Journals Online (AJOL)

    1974-06-08

    Jun 8, 1974 ... The vemricular extrasystoles reflect the>:e changes-as primary S-T segment and T-wave changes (see below)-- more clearly. The S-T segments are markedly elevated to about 3 mm. The S-T segment configuration is clearly horizontal with a very sharp-angled ST-T junction. The associated T waves are tall ...

  17. Assessment of Human Exposure to Magnetic Fields Produced by Domestic Appliances (invited paper)

    International Nuclear Information System (INIS)

    Preece, A.W.; Kaune, W.T.; Grainger, P.; Golding, J.

    1999-01-01

    A study of 50 homes and their appliances examined whether a detailed appliance-use questionnaire and survey would yield data comparable with direct personal monitoring. This was coupled with direct measurement of the appliances in use to determine the field at 50 cm and 1 m. The findings were that individual time-weighted average (TWA) exposures calculated from questionnaire and activity diaries in conjunction with the appliance magnetic field were unrelated to actual personal exposure measurement. It was concluded that questionnaires are of little or no value for TWA estimation. However, peak exposure and short-term temporal variability could be modelled in subjects spending at least 15 min per day within 1 m of an operating microwave cooker or conventional cooker. This method could be extended to other appliances. (author)

  18. PROTOPLANETARY DISK MASSES FROM STARS TO BROWN DWARFS

    International Nuclear Information System (INIS)

    Mohanty, Subhanjoy; Mortlock, Daniel; Greaves, Jane; Pascucci, Ilaria; Apai, Daniel; Scholz, Aleks; Thompson, Mark; Lodato, Giuseppe; Looper, Dagny

    2013-01-01

    We present SCUBA-2 850 μm observations of seven very low mass stars (VLMS) and brown dwarfs (BDs). Three are in Taurus and four in the TW Hydrae Association (TWA), and all are classical T Tauri (cTT) analogs. We detect two of the three Taurus disks (one only marginally), but none of the TWA ones. For standard grains in cTT disks, our 3σ limits correspond to a dust mass of 1.2 M ⊕ in Taurus and a mere 0.2 M ⊕ in the TWA (3-10× deeper than previous work). We combine our data with other submillimeter/millimeter (sub-mm/mm) surveys of Taurus, ρ Oph, and the TWA to investigate the trends in disk mass and grain growth during the cTT phase. Assuming a gas-to-dust mass ratio of 100:1 and fiducial surface density and temperature profiles guided by current data, we find the following. (1) The minimum disk outer radius required to explain the upper envelope of sub-mm/mm fluxes is ∼100 AU for intermediate-mass stars, solar types, and VLMS, and ∼20 AU for BDs. (2) While the upper envelope of apparent disk masses increases with M * from BDs to VLMS to solar-type stars, no such increase is observed from solar-type to intermediate-mass stars. We propose this is due to enhanced photoevaporation around intermediate stellar masses. (3) Many of the disks around Taurus and ρ Oph intermediate-mass and solar-type stars evince an opacity index of β ∼ 0-1, indicating significant grain growth. Of the only four VLMS/BDs in these regions with multi-wavelength measurements, three are consistent with considerable grain growth, though optically thick disks are not ruled out. (4) For the TWA VLMS (TWA 30A and B), combining our 850 μm fluxes with the known accretion rates and ages suggests substantial grain growth by 10 Myr, comparable to that in the previously studied TWA cTTs Hen 3-600A and TW Hya. The degree of grain growth in the TWA BDs (2M1207A and SSPM1102) remains largely unknown. (5) A Bayesian analysis shows that the apparent disk-to-stellar mass ratio has a roughly

  19. Notas de filología micénica, III: el silabograma *86

    Directory of Open Access Journals (Sweden)

    José L. Melena

    1983-12-01

    Full Text Available In spite of various efforts, a few syllabograms in the Mycenaean Linear B signary are still unidentified and hence they remain untransliterated. The following is an attempt to deciphering the value of the syllabogram *86 attested exclusively in personal and place names, a fact that increases the difficulties in discovering its value, since contextual hints are not at work. After reviewing the dossier of *86, the author puts forward a transliteration dwa for this sign, which is therefore to be aligned with such compound signs as dwe and dwo. The existence of such a triplet of signs (dwa dwe dwo prompts the subsequent search for a sign twa to be similarly aligned with the extant twe and two. In an excursus the author thinks of the syllabogram *82 as the most tempting candidate to fill the slot for twa in the Linear B signary.

  20. The effect of powder properties on sintering, microstructure, mechanical strength and degradability of beta-tricalcium phosphate/calcium silicate composite bioceramics

    Energy Technology Data Exchange (ETDEWEB)

    Lin Kaili; Chang Jiang; Shen Ruxiang, E-mail: jchang@mail.sic.ac.c [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai 200050 (China)

    2009-12-15

    The effect of powder properties on sintering, microstructure, mechanical strength and degradability of beta-tricalcium phosphate/Calcium silicate (beta-Ca{sub 3}(PO{sub 4}){sub 2}/CaSiO{sub 3}, beta-TCP/CS) composite bioceramics was investigated. beta-TCP/CS composite powders with a weight ratio of 50:50 were prepared by three different methods: mechanical milling method (TW-A), two-step chemical precipitation method (TW-B) and in situ chemical co-precipitation method (TW-C), and then the three composite powders were uniaxially compacted at 30 MPa, followed by cold isostatic pressing into rectangular-prism-shaped specimens under a pressure of 200 MPa for 15 min, and then sintered at 1150 deg. C for 5 h. The TW-B powders with less agglomerative morphologies and uniform nano-size particles attained 96.14% relative density (RD). A uniform microstructure with about 120 nm grains was observed. Whereas, the samples obtained from TW-A and TW-C powders only reached a RD of 63.08% and 78.86%, respectively. The bending strength of the samples fabricated from TW-B reached 125 MPa, which was more than 3.7 and 1.5 times higher as compared with that of samples obtained from TW-A and TW-C powders, respectively. Furthermore, the degradability of the samples fabricated from TW-B powders was obviously lower than that of the samples fabricated from TW-A and TW-C powders.

  1. Calibration and Application of Passive Sampling in Drinking Water for Perfluoroalkyl Substances

    OpenAIRE

    Persson, Caroline

    2015-01-01

    Perfluoroalkyl substances (PFASs) are global environmental contaminants and a need for monitoring levels has arisen due to their persistency and their ability to bioaccumulate. One relatively novel method of monitoring for both long and short time intervals and generating time-weighted average (TWA) concentrations is passive sampling for which no power, maintenance and supervision is required. The polar organic compound integrative sampler (POCIS) with a weak anion exchange (WAX) sorbent and ...

  2. Metal Dust Exposure and Respiratory Health of Male Steel Work¬ers in Terengganu, Malaysia

    OpenAIRE

    Nurul Ainun HAMZAH; Shamsul Bahri MOHD TAMRIN; Noor Hassim ISMAIL

    2015-01-01

    Background: This cross sectional study was carried out to determine the relationship between metal dust exposure and respiratory health in male steel workers in Terengganu, Malaysia.Methods: Subjects were interviewed using a structured questionnaire from British Medical Research Council (BMRC) Questionnaire regarding respiratory symptoms and were examined their lung function using spirometer.Results: The mean trace metal dusts concentration TWA8 for cobalt and chromium in most of work unit ex...

  3. Mapping sound intensities by seating position in a university concert band: A risk of hearing loss, temporary threshold shifts, and comparisons with standards of OSHA and NIOSH

    Science.gov (United States)

    Holland, Nicholas Vedder, III

    Exposure to loud sounds is one of the leading causes of hearing loss in the United States. The purpose of the current research was to measure the sound pressure levels generated within a university concert band and determine if those levels exceeded permissible sound limits for exposure according to criteria set by the Occupational Safety and Health Administration (OSHA) and the National Institute of Occupational Safety and Health (NIOSH). Time-weighted averages (TWA) were obtained via a dosimeter during six rehearsals for nine members of the ensemble (plus the conductor), who were seated in frontal proximity to "instruments of power" (trumpets, trombones, and percussion; (Backus, 1977). Subjects received audiometer tests prior to and after each rehearsal to determine any temporary threshold shifts (TTS). Single sample t tests were calculated to compare TWA means and the maximum sound intensity exposures set by OSHA and NIOSH. Correlations were calculated between TWAs and TTSs, as well as TTSs and the number of semesters subjects reported being seated in proximity to instruments of power. The TWA-OSHA mean of 90.2 dBA was not significantly greater than the specified OSHA maximum standard of 90.0 dBA (p > .05). The TWA-NIOSH mean of 93.1 dBA was, however, significantly greater than the NIOSH specified maximum standard of 85.0 dBA (p OSHA, r = .20 for NIOSH); the correlation between TTSs and semesters of proximity to instruments of power was also considered weak (r = .13). TWAs cumulatively exceeded both association's sound exposure limits at 11 specified locations (nine subjects and both ears of the conductor) throughout the concert band's rehearsals. In addition, hearing acuity, as determined by TTSs, was substantially affected negatively by the intensities produced in the concert band. The researcher concluded that conductors, as well as their performers, must be aware of possible damaging sound intensities in rehearsals or performances.

  4. EFAM GTP-CREEP 02 - the GKSS test procedure for determining the creep crack extension of materials

    International Nuclear Information System (INIS)

    Schwalbe, K.H.

    2002-01-01

    This document describes a fracture mechanics method in procedural form for determining the creep crack extension of materials. It is based on the unified fracture mechanics test method EFAM GTP 02, the ASTM standard E 1457-98, activities of VAMAS TWA 19, and GKSS experience in creep crack extension testing. It introduces novel features such as the rate of the δ 5 crack tip opening displacement, the crack tip opening angle, and the middle cracked tension specimen. (orig.) [de

  5. An evaluation of short-term exposures of brake mechanics to asbestos during automotive and truck brake cleaning and machining activities.

    Science.gov (United States)

    Richter, Richard O; Finley, Brent L; Paustenbach, Dennis J; Williams, Pamela R D; Sheehan, Patrick J

    2009-07-01

    Historically, the greatest contributions to airborne asbestos concentrations during brake repair work were likely due to specific, short-duration, dust-generating activities. In this paper, the available short-term asbestos air sampling data for mechanics collected during the cleaning and machining of vehicle brakes are evaluated to determine their impact on both short-term and daily exposures. The high degree of variability and lack of transparency for most of the short-term samples limit their use in reconstructing past asbestos exposures for brake mechanics. However, the data are useful in evaluating how reducing short-term, dust-generating activities reduced long-term exposures, especially for auto brake mechanics. Using the short-term dose data for grinding brake linings from these same studies, in combination with existing time-weighted average (TWA) data collected in decades after grinding was commonplace in rebuilding brake shoes, an average 8-h TWA of approximately 0.10 f/cc was estimated for auto brake mechanics that performed arc grinding of linings during automobile brake repair (in the 1960s or earlier). In the 1970s and early 1980s, a decline in machining activities led to a decrease in the 8-h TWA to approximately 0.063 f/cc. Improved cleaning methods in the late 1980s further reduced the 8-h TWA for most brake mechanics to about 0.0021 f/cc. It is noteworthy that when compared with the original OSHA excursion level, only 15 of the more than 300 short-term concentrations for brake mechanics measured during the 1970s and 1980s possibly exceeded the standard. Considering exposure duration, none of the short-term exposures were above the current OSHA excursion level.

  6. A Marine Hazardous Substances Data System. Volume 2.

    Science.gov (United States)

    1985-12-01

    HAZARDOUS CARGOS (CONT’D) *20-DEC-85 CHEMICAL NAIIE CHRIS CFR OTHER TLV-TWA SEG CODE ROUTE PPM NO. WAX : CANDELILLA D 684 WAX . CARNAUBA WCA D 685 WAX ...50 693 * WAX : PARAFFIN IJPF D 2 MG/M3 696 MXYLENE XLM D 100 693 O-XYLENE XLO D 100 694 P-XYLENE XLP D 100 695 ZINC DIALKYLDITHIOPHOSPHATE ZDP D 10

  7. Using Smart Devices to Measure Intermittent Noise in the Workplace

    Directory of Open Access Journals (Sweden)

    Benjamin Roberts

    2017-01-01

    Full Text Available Purpose: To determine the accuracy of smart devices (iPods to measure intermittent noise and integrate a noise dose in the workplace. Materials and Methods: In experiment 1, four iPods were each paired with a Larson Davis Spark dosimeter and exposed to randomly fluctuating pink noise in a reverberant sound chamber. Descriptive statistics and the mean difference between the iPod and its paired dosimeter were calculated for the 1-s data logged measurements. The calculated time weighted average (TWA was also compared between the devices. In experiment 2, 15 maintenance workers and 14 office workers wore an iPod and dosimeter during their work-shift for a maximum of five workdays. A mixed effects linear regression model was used to control for repeated measures and to determine the effect of the device type on the projected 8-h TWA. Results: In experiment 1, a total of 315,306 1-s data logged measurements were made. The interquartile range of the mean difference fell within ±2.0 A-weighted decibels (dBA, which is the standard used by the American National Standards Institute to classify a type 2 sound level meter. The mean difference of the calculated TWA was within ±0.5 dBA except for one outlier. In experiment 2, the results of the mixed effects model found that, on average, iPods measured an 8-h TWA 1.7 dBA higher than their paired dosimeters. Conclusion: This study shows that iPods have the ability to make reasonably accurate noise measurements in the workplace, but they are not as accurate as traditional noise dosimeters.

  8. A Study to Determine the Role of Competition in Contracting for the Movement of Air Freight within the Domestic Market.

    Science.gov (United States)

    1980-06-01

    ratemaking func- tion under part 288 [of the FAA Act of 19581. On the basis of this review, we propose for three principal reasons to amend Part 288 to...the six carriers and to the comments of TWA . . . none of the commenters oppose adoption of the basic proposal. . . . The six air carriers com- menting...Assistant for Civil Air Division, Directorate of Plans, Headquarters MAC. The researchers were aware that the basic requirements are generated at the

  9. Applying the Theory of Work Adjustment to Latino Immigrant Workers: An Exploratory Study.

    Science.gov (United States)

    Eggerth, Donald E; Flynn, Michael A

    2012-02-01

    Blustein mapped career decision making onto Maslow's model of motivation and personality and concluded that most models of career development assume opportunities and decision-making latitude that do not exist for many individuals from low income or otherwise disadvantaged backgrounds. Consequently, Blustein argued that these models may be of limited utility for such individuals. Blustein challenged researchers to reevaluate current career development approaches, particularly those assuming a static world of work, from a perspective allowing for changing circumstances and recognizing career choice can be limited by access to opportunities, personal obligations, and social barriers. This article represents an exploratory effort to determine if the theory of work adjustment (TWA) might meaningfully be used to describe the work experiences of Latino immigrant workers, a group living with severe constraints and having very limited employment opportunities. It is argued that there is significant conceptual convergence between Maslow's hierarchy of needs and the work reinforcers of TWA. The results of an exploratory, qualitative study with a sample of 10 Latino immigrants are also presented. These immigrants participated in key informant interviews concerning their work experiences both in the United States and in their home countries. The findings support Blustein's contention that such workers will be most focused on basic survival needs and suggest that TWA reinforcers are descriptive of important aspects of how Latino immigrant workers conceptualize their jobs.

  10. WISEA J114724.10-204021.3: A FREE-FLOATING PLANETARY MASS MEMBER OF THE TW HYA ASSOCIATION

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Adam C.; Windsor, James; Cushing, Michael C. [Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606 (United States); Kirkpatrick, J. Davy [Infrared Processing and Analysis Center, California Institute of Technology, MS 100-22, Pasadena, CA 91125 (United States); Wright, Edward L., E-mail: Adam.Schneider@Utoledo.edu [Department of Physics and Astronomy, University of California, Los Angeles, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States)

    2016-05-01

    We present WISEA J114724.10-204021.3, a young, low-mass, high-probability member of the TW Hya association (TWA). WISEA J114724.10-204021.3 was discovered based on its red AllWISE color ( W 1 − W 2 = 0.63 mag) and extremely red 2MASS J − K {sub S} color (>2.64 mag), the latter of which is confirmed with near-infrared photometry from the Visible and Infrared Survey Telescope for Astronomy Hemisphere Survey ( J − K {sub S} = 2.57 ± 0.03). Follow-up near-infrared spectroscopy shows a spectral type of L7 ± 1 as well as several spectroscopic indicators of youth. These include a peaked H -band shape and a steeper K -band slope, traits typically attributed to low surface gravity. The sky position, proper motion, and distance estimates of WISEA J114724.10-204021.3 are all consistent with membership in the ∼10 Myr old TWA. Using the age of the TWA and evolutionary models, we estimate the mass of WISEA J114724.10-204021.3 to be 5–13 M {sub Jup}, making it one of the youngest and lowest-mass free-floating objects yet discovered in the Solar neighborhood.

  11. Assessment of noise in the airplane cabin environment.

    Science.gov (United States)

    Zevitas, Christopher D; Spengler, John D; Jones, Byron; McNeely, Eileen; Coull, Brent; Cao, Xiaodong; Loo, Sin Ming; Hard, Anna-Kate; Allen, Joseph G

    2018-03-15

    To measure sound levels in the aircraft cabin during different phases of flight. Sound level was measured on 200 flights, representing six aircraft groups using continuous monitors. A linear mixed-effects model with random intercept was used to test for significant differences in mean sound level by aircraft model and across each flight phase as well as by flight phase, airplane type, measurement location and proximity to engine noise. Mean sound levels across all flight phases and aircraft groups ranged from 37.6 to >110 dB(A) with a median of 83.5 dB(A). Significant differences in noise levels were also observed based on proximity to the engines and between aircraft with fuselage- and wing mounted engines. Nine flights (4.5%) exceeded the recommended 8-h TWA exposure limit of 85 dB(A) by the NIOSH and ACGIH approach, three flights (1.5%) exceeded the 8-h TWA action level of 85 dB(A) by the OSHA approach, and none of the flights exceeded the 8-h TWA action level of 90 dB(A) by the OSHA PEL approach. Additional characterization studies, including personal noise dosimetry, are necessary to document accurate occupational exposures in the aircraft cabin environment and identify appropriate response actions. FAA should consider applying the more health-protective NIOSH/ACGIH occupational noise recommendations to the aircraft cabin environment.

  12. The Composite Strain Index (COSI) and Cumulative Strain Index (CUSI): methodologies for quantifying biomechanical stressors for complex tasks and job rotation using the Revised Strain Index.

    Science.gov (United States)

    Garg, Arun; Moore, J Steven; Kapellusch, Jay M

    2017-08-01

    The Composite Strain Index (COSI) quantifies biomechanical stressors for complex tasks consisting of exertions at different force levels and/or with different exertion times. The Cumulative Strain Index (CUSI) further integrates biomechanical stressors from different tasks to quantify exposure for the entire work shift. The paper provides methodologies to compute COSI and CUSI along with examples. Complex task simulation produced 169,214 distinct tasks. Use of average, time-weighted average (TWA) and peak force and COSI classified 66.9, 28.2, 100 and 38.9% of tasks as hazardous, respectively. For job rotation the simulation produced 10,920 distinct jobs. TWA COSI, peak task COSI and CUSI classified 36.5, 78.1 and 66.6% jobs as hazardous, respectively. The results suggest that the TWA approach systematically underestimates the biomechanical stressors and peak approach overestimates biomechanical stressors, both at the task and job level. It is believed that the COSI and CUSI partially address these underestimations and overestimations of biomechanical stressors. Practitioner Summary: COSI quantifies exposure when applied hand force and/or duration of that force changes during a task cycle. CUSI integrates physical exposures from job rotation. These should be valuable tools for designing and analysing tasks and job rotation to determine risk of musculoskeletal injuries.

  13. Applying the Theory of Work Adjustment to Latino Immigrant Workers: An Exploratory Study

    Science.gov (United States)

    Eggerth, Donald E.; Flynn, Michael A.

    2015-01-01

    Blustein mapped career decision making onto Maslow’s model of motivation and personality and concluded that most models of career development assume opportunities and decision-making latitude that do not exist for many individuals from low income or otherwise disadvantaged backgrounds. Consequently, Blustein argued that these models may be of limited utility for such individuals. Blustein challenged researchers to reevaluate current career development approaches, particularly those assuming a static world of work, from a perspective allowing for changing circumstances and recognizing career choice can be limited by access to opportunities, personal obligations, and social barriers. This article represents an exploratory effort to determine if the theory of work adjustment (TWA) might meaningfully be used to describe the work experiences of Latino immigrant workers, a group living with severe constraints and having very limited employment opportunities. It is argued that there is significant conceptual convergence between Maslow’s hierarchy of needs and the work reinforcers of TWA. The results of an exploratory, qualitative study with a sample of 10 Latino immigrants are also presented. These immigrants participated in key informant interviews concerning their work experiences both in the United States and in their home countries. The findings support Blustein’s contention that such workers will be most focused on basic survival needs and suggest that TWA reinforcers are descriptive of important aspects of how Latino immigrant workers conceptualize their jobs. PMID:26345693

  14. Reduced intrinsic heart rate is associated with reduced arrhythmic susceptibility in guinea-pig heart.

    Science.gov (United States)

    Osadchii, Oleg E

    2014-12-01

    In the clinical setting, patients with slower resting heart rate are less prone to cardiovascular death compared with those with elevated heart rate. However, electrophysiological adaptations associated with reduced cardiac rhythm have not been thoroughly explored. In this study, relationships between intrinsic heart rate and arrhythmic susceptibility were examined by assessments of action potential duration (APD) rate adaptation and inducibility of repolarization alternans in sinoatrial node (SAN)-driven and atrioventricular (AV)-blocked guinea-pig hearts perfused with Langendorff apparatus. Electrocardiograms, epicardial monophasic action potentials, and effective refractory periods (ERP) were assessed in normokalemic and hypokalemic conditions. Slower basal heart rate in AV-blocked hearts was associated with prolonged ventricular repolarization during spontaneous beating, and with attenuated APD shortening at increased cardiac activation rates during dynamic pacing, when compared with SAN-driven hearts. During hypokalemic perfusion, the inducibility of repolarization alternans and tachyarrhythmia by rapid pacing was found to be lower in AV-blocked hearts. This difference was ascribed to prolonged ERP in the setting of reduced basal heart rate, which prevented ventricular capture at critically short pacing intervals required to induce arrhythmia. Reduced basal heart rate is associated with electrophysiological changes that prevent electrical instability upon an abrupt cardiac acceleration.

  15. Utility of 12-lead electrocardiogram for differentiating paroxysmal supraventricular tachycardias in dogs.

    Science.gov (United States)

    Santilli, R A; Perego, M; Crosara, S; Gardini, F; Bellino, C; Moretti, P; Spadacini, G

    2008-01-01

    The 12-lead surface ECG is validated for differentiating supraventricular tachycardias (SVT) in humans. Despite the description of SVT in veterinary medicine, no studies have analyzed the electrocardiographic features of this type of arrhythmias in dogs. To describe the specific electrocardiographic criteria used to differentiate the most common SVT in dogs. Twenty-three dogs examined at Clinica Veterinaria Malpensa for SVT with the mechanism documented by electrophysiologic studies (EPS). Twelve-lead electrocardiographic variables obtained from 14 dogs with orthodromic atrioventricular reciprocating tachycardia (OAVRT) and 9 dogs with focal atrial tachycardia (FAT) were compared. Dogs with FAT had faster heart rates (278 +/- 62 versus 229 +/- 42 bpm; P= .049) and less QRS alternans (33 versus 86%; P= .022). P waves appeared during tachycardia in 22 dogs, with a superior axis in 100% of OAVRT and 22% of FAT (P < .001). OAVRT was characterized by a shorter RP interval (85.0 +/- 16.8 versus 157.1 +/- 37.3 ms; P < .001) and smaller RP/PR ratio (0.60 +/- 0.18 versus 1.45 +/- 0.52; P < .001). Repolarization anomalies were present in 64% of OAVRT and no FAT (P < .001). Multivariate analysis identified QRS alternans and a positive P wave in aVR during tachycardia as independent predictors of arrhythmia type. Electrocardiographic criteria used in people for differentiating SVT can also be applied in dogs.

  16. Rare Pediastrum species (Chlorophyceae from Polish coastal lakes

    Directory of Open Access Journals (Sweden)

    Joanna Kowalska

    2011-01-01

    Full Text Available An account is given of the occurrence of Pediastrum (Chlorophyceae, Sphaeropleales in five eutrophic coastal lakes (Jamno, Bukowo, Gardno, Łebsko and Sarbsko in northern Poland, together with morphological data of the species and more detailed taxonomic and ecological information for three taxa which appear to be rare world wide. These are P. musterii, P. orientale and P. alternans; the first is recorded for the first time from central Europe. P. orientale and P. alternans show considerable morphological variability under different environmental conditions, indicating the need for further studies. The studied lakes seem to be especially favourable for Pediastrum, with a total of eight species (15 taxa in the phytoplankton noted during the summer. However, the relative frequency of the genus in the overall algal communities was low. The most frequent species were P. boryanum, P. kawraiskyi and P. duplex and these were accompanied by cyanobacteria, coccal green algae (Chlorophyceae, Chlorococcales and diatoms (Bacillariophyceae. All the Pediastrum taxa were documented using LM and SEM.

  17. Risk assessments using the Strain Index and the TLV for HAL, Part II: Multi-task jobs and prevalence of CTS.

    Science.gov (United States)

    Kapellusch, Jay M; Silverstein, Barbara A; Bao, Stephen S; Thiese, Mathew S; Merryweather, Andrew S; Hegmann, Kurt T; Garg, Arun

    2018-02-01

    The Strain Index (SI) and the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit value for hand activity level (TLV for HAL) have been shown to be associated with prevalence of distal upper-limb musculoskeletal disorders such as carpal tunnel syndrome (CTS). The SI and TLV for HAL disagree on more than half of task exposure classifications. Similarly, time-weighted average (TWA), peak, and typical exposure techniques used to quantity physical exposure from multi-task jobs have shown between-technique agreement ranging from 61% to 93%, depending upon whether the SI or TLV for HAL model was used. This study compared exposure-response relationships between each model-technique combination and prevalence of CTS. Physical exposure data from 1,834 workers (710 with multi-task jobs) were analyzed using the SI and TLV for HAL and the TWA, typical, and peak multi-task job exposure techniques. Additionally, exposure classifications from the SI and TLV for HAL were combined into a single measure and evaluated. Prevalent CTS cases were identified using symptoms and nerve-conduction studies. Mixed effects logistic regression was used to quantify exposure-response relationships between categorized (i.e., low, medium, and high) physical exposure and CTS prevalence for all model-technique combinations, and for multi-task workers, mono-task workers, and all workers combined. Except for TWA TLV for HAL, all model-technique combinations showed monotonic increases in risk of CTS with increased physical exposure. The combined-models approach showed stronger association than the SI or TLV for HAL for multi-task workers. Despite differences in exposure classifications, nearly all model-technique combinations showed exposure-response relationships with prevalence of CTS for the combined sample of mono-task and multi-task workers. Both the TLV for HAL and the SI, with the TWA or typical techniques, appear useful for epidemiological studies and surveillance

  18. Youngest Brown Dwarf Yet in a Multiple Stellar System

    Science.gov (United States)

    2000-07-01

    ... and the Sharpest Optical Image (0.18 arcsec) from the VLT so far...! Astronomers are eager to better understand the formation of stars and planets - with an eye on the complex processes that lead to the emergence of our own solar system some 4600 million years ago. Brown Dwarfs (BDs) play a special role in this context. Within the cosmic zoo, they represent a class of "intermediate" objects. While they are smaller than normal stars, they shine by their own energy for a limited time, in contrast to planets. Recent observations with the ESO Very Large Telescope (VLT) of a "young" Brown Dwarf in a multiple stellar system are taking on a particular importance in this connection. An evaluation of the new data by an international team of astronomers [1] shows that it is by far the youngest of only four such objects found in a stellar system so far. The results are now providing new insights into the stellar formation process. This small object is known as TWA-5 B and with a mass of only 15 - 40 times that of Jupiter, it is near the borderline between planets and Brown Dwarfs, cf. the explanatory Appendix to this Press Release. However, visible and infrared VLT spectra unambiguously classify it in the latter category. Accurate positional measurements with the Hubble Space Telescope (HST) and the VLT hint that it is orbiting the central, much heavier and brighter star in this system, TWA-5 A (itself a close double star of which each component presumably has a mass of 0.75 solar masses), with a period that may be as long as 900 years. And, by the way, an (I-band) image of the TWA-5 system is the sharpest delivered by the VLT so far, with an image size of only 0.18 arcsec [2]! Brown Dwarfs: a cool subject In current astronomical terminology, Brown Dwarfs (BDs) are objects whose masses are below those of normal stars - the borderline is believed to be about 8% of the mass of our Sun - but larger than those of planets, cf. [3]. Unlike normal stars, Brown Dwarfs are unable

  19. Electrocardiographic manifestations of hyperkalemia in hemodialysis patients

    Directory of Open Access Journals (Sweden)

    Nemati Eghlim

    2010-01-01

    Full Text Available This study was performed to evaluate whether any electrocardiogram (ECG para-meter can predict the presence of hyperkalemia in patients on maintenance hemodialysis (HD. In January 2006, we conducted a cross-sectional study of 80 stable patients with end-stage renal disease from four university-based HD units of Tehran, Iran, receiving conventional thrice-weekly HD. Pre-HD serum electrolyte values and conventional 12-lead ECG were obtained from each pa-tient. Bivariate linear regression was used for assessing relationship of the study variables with hyperkalemia (K + > 5.2 mg/dL. Multivariable logistic regression was used for evaluating inde-pendent relationship between decreased T wave duration (≤ 170 ms and other variables. Bivariate correlation analysis showed a significant inverse correlation between serum potassium concentration and T wave duration (P < 0.05. None of the patients with serum potassium of ≥ 5.6 mg/dL had T wave duration > 200 ms. Multivariate logistic analysis, after adjustment for other factors, also showed a significant relationship between decreased T wave duration (≤ 170 ms and hyper-kalemia. We conclude that although hyperkalemia does not induce the usual ECG changes in HD patients, decreased T wave duration was found to be a good indicator of this lethal condition.

  20. ALTERATIONS IN ELECTROCARDIOGRAMS OF LABRADOR RETRIEVER DOGS DURING HANDLING WITH AND WITHOUT GLOVES

    Directory of Open Access Journals (Sweden)

    Swagat Mohapatra

    2016-12-01

    Full Text Available Healthy male Labrador Retriever dogs (n=8 aged between one to three years constituted the study material. The study was carried out to peruse the alterations in electrocardiograms, when the attendant restrained the dogs with bare hands and when the dogs were restrained by the attendant wearing gloves. The mean amplitude of P wave was higher in dogs handled with gloves. Similarly, the amplitudes of QRS complex and T wave were higher in the electrocardiograms of dogs handled with insulated hands. Meanwhile, the duration of T wave and Q-T interval were higher in the electrocardiograms recorded without gloves in hands. However, no alterations were perceived with respect to the duration of P wave, duration of T wave, the P-R interval, R-R interval and the heart rate. Except for the amplitude of P wave, no other differences were statistically significant. The study reported the alterations in the electrocardiogram while handling the animals with bare hands.

  1. Case control study of Electrocardiographic changes in pregnant women

    Directory of Open Access Journals (Sweden)

    Sharddha Singh

    1995-09-01

    Full Text Available Pregnancy causes significant haemodynamic changes and imposes stress on the cardiovascular system. Many healthy women develop signs and symptoms of cardiovascular overload during pregnancy. Knowledge of established normal changes in EKG during normal pregnancy is important. The aim of our study was to detect any early damage to myocardium during pregnancy with the help of electrocardiography. Total of 20 pregnant and 20 non pregnant women were studied. The most significant change observed in ECG was T wave inversion with odds ratio 7.43 (95%. Cl = 1.49 to 41.00. P= 0.005. Stratified analysis showed that there was no confounding role of age in the relationship of T wave inversion and ECG findings. Moreover, a significant relationship between anaemia and T wave inversion was also observed. (0=1.74 ■ 1101.06; P= 0.007.

  2. Wellen′s syndrome: An ominous EKG pattern

    Directory of Open Access Journals (Sweden)

    Mead Nicole

    2009-01-01

    Full Text Available Wellen′s syndrome is a characteristic T-wave on an electrocardiogram during a pain-free period in a patient with intermittent chest pain. This finding suggests a high-degree stenosis of the proximal left anterior descending (LAD coronary artery that will soon result in an acute anterior wall myocardial infarction (MI if the patient is not urgently catheterized and the occlusion opened. This case report discusses a young male patient with no known cardiac disease with an EKG that demonstrates the classic Wellen′s T-waves. He was urgently taken to cardiac catheterization and his 95% proximal LAD stenosis was reduced via drug-eluding stent. Through knowledge of Wellen′s T-waves, more anterior wall MIs can be prevented.

  3. Changes in the electrocardiograms of rats and dogs exposed to dc magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Gaffey, C.T.; Tenforde, T.S.

    1979-03-01

    An evaluation of cardiovascular performance in magnetic fields (MF) is being undertaken. Cardiovascular performance is evaluated as a function of the MF strength. Since the vector characteristics of MF may be a factor influencing cardiovascular function, the positional arrangement of animals in a MF is being tested. In practice, each test animal is inserted between the poles of a magnet in a selected orientation that locates the heart in the center of the MF. The electrocardogram (ECG) is recorded before, during, and following the application of a MF. The interval between summits of the R waves allows the average heart rate to be obtained. The average respiratory rate is measured from the baseline shifts in the ECG trace. The major change in the ECG pattern induced by a MF is an increase in the amplitude of the T wave of rats and dogs. In our rat study a 20,000 gauss field increased the T wave by about 450%; the dog's T wave was increased 750% by a 16,000 gauss field. These biomagnetic effects appear to be reversible. Out experiments with rats and dogs were designed to test for the presence of a magnetic strength threshold (MST) to evoke T wave enhancement. The MST is defined as the minimum number of gauss to product a measurable change with T wave amplitude. The MTS is 3.0 kgauss for rats and 0.9 kgauss for dogs. Augmentation of the T wave was found to be greatest when thelines of the MF were perpendicular to the long axis of the body and least when parallel. Hence, the orientation of the subject in the MF influences the ECG profile.

  4. ECG (Electrocardiogram) Interpretation Training Program - Reference Manual

    Science.gov (United States)

    1984-05-08

    begins to the start of the Q, or R if the Q is absent. Table #1 Rate Below 70 71-90 91-110 111-130 Above 130 Small adults 0.21 0.20 0.19 0.18...children. In adults they may indicate pericarditis. A sharply pointed T wave may be indicative of a myocardial infarct. T waves are normally 5mm. or...A longer than normal QT may indicate congestive heart failure, MI, hypocalcemia , or toxicity from quinidine,procaine amide, or phenothiazines

  5. Circadian profile of QT interval and QT interval variability in 172 healthy volunteers

    DEFF Research Database (Denmark)

    Bonnemeier, Hendrik; Wiegand, Uwe K H; Braasch, Wiebke

    2003-01-01

    of sleep. QT and R-R intervals revealed a characteristic day-night-pattern. Diurnal profiles of QT interval variability exhibited a significant increase in the morning hours (6-9 AM; P ... lower at day- and nighttime. Aging was associated with an increase of QT interval mainly at daytime and a significant shift of the T wave apex towards the end of the T wave. The circadian profile of ventricular repolarization is strongly related to the mean R-R interval, however, there are significant...

  6. Perceptions of team members working in cleft services in the United kingdom: a pilot study.

    Science.gov (United States)

    Scott, Julia K; Leary, Sam D; Ness, Andy R; Sandy, Jonathan R; Persson, Martin; Kilpatrick, Nicky; Waylen, Andrea E

    2015-01-01

    Cleft care provision in the United Kingdom has been centralized over the past 15 years to improve outcomes for children born with cleft lip and palate. However, to date, there have been no investigations to examine how well these multidisciplinary teams are performing. In this pilot study, a cross-sectional questionnaire surveyed members of all health care specialties working to provide cleft care in 11 services across the United Kingdom. Team members were asked to complete the Team Work Assessment (TWA) to investigate perceptions of team working in cleft services. The TWA comprises 55 items measuring seven constructs: team foundation, function, performance and skills, team climate and atmosphere, team leadership, and team identity; individual constructs were also aggregated to provide an overall TWA score. Items were measured using five-point Likert-type scales and were converted into percentage agreement for analysis. Responses were received from members of every cleft team. Ninety-nine of 138 cleft team questionnaires (71.7%) were returned and analyzed. The median (interquartile range) percentage of maximum possible score across teams was 75.5% (70.8, 88.2) for the sum of all items. Team performance and team identity were viewed most positively, with 82.0% (75.0, 88.2) and 88.4% (82.2, 91.4), respectively. Team foundation and leadership were viewed least positively with 79.0% (72.6, 84.6) and 76.6% (70.6, 85.4), respectively. Cleft team members perceive that their teams work well, but there are variations in response according to construct.

  7. Application of Polar Organic Chemical Integrative Sampler (POCIS) to monitor emerging contaminants in tropical waters.

    Science.gov (United States)

    Bayen, Stéphane; Segovia, Elvagris; Loh, Lay Leng; Burger, David F; Eikaas, Hans S; Kelly, Barry C

    2014-06-01

    Tools specifically validated for tropical environments are needed to accurately describe the behavior of chemical contaminants in tropical ecosystems. In the present study, sampling rates (Rs) were determined for the commercial pharmaceutical-type Polar Organic Chemical Integrative Sampler (POCIS) with a 45.8cm(2) exposure surface for 35 Pharmaceutically Active Compounds (PhACs) and Endocrine Disrupting Compounds (EDCs), of which eight compounds (albuterol, atorvastatin, diltiazem, dilantin, enalapril, norfluoxetine, risperidone and warfarin) were reported for the first time. These sampling rates were measured in an outdoor laboratory calibration setup to best capture diurnal tropical temperature variations (29±3°C). The effect of stirring and salinity was investigated. For all compounds, the sampling rates were higher under stirred conditions as compared to quiescent conditions. Calibration results in the presence of 30g sodium chloride support that the effects of salinity on POCIS sampling rates are compound-specific. Comparisons between Time-Weight Average (TWA) water concentrations using POCIS and spot sample levels in the field (2 lake and 1 mangrove estuary sites) are presented. Results showed that POCIS TWA concentrations were in agreement with spot sample concentrations for these aquatic systems. Results indicate that POCIS can be used to effectively measure the TWA concentration for a range of PhACs and EDCs in tropical waters. However, based on the results from mass balance and field deployments, POCIS did not appear suitable for compounds with a low mass balance recovery during calibration (e.g. triclosan and linuron in this study). Copyright © 2014 Elsevier B.V. All rights reserved.

  8. An analysis of collegiate band directors' exposure to sound pressure levels

    Science.gov (United States)

    Roebuck, Nikole Moore

    Noise-induced hearing loss (NIHL) is a significant but unfortunate common occupational hazard. The purpose of the current study was to measure the magnitude of sound pressure levels generated within a collegiate band room and determine if those sound pressure levels are of a magnitude that exceeds the policy standards and recommendations of the Occupational Safety and Health Administration (OSHA), and the National Institute of Occupational Safety and Health (NIOSH). In addition, reverberation times were measured and analyzed in order to determine the appropriateness of acoustical conditions for the band rehearsal environment. Sound pressure measurements were taken from the rehearsal of seven collegiate marching bands. Single sample t test were conducted to compare the sound pressure levels of all bands to the noise exposure standards of OSHA and NIOSH. Multiple regression analysis were conducted and analyzed in order to determine the effect of the band room's conditions on the sound pressure levels and reverberation times. Time weighted averages (TWA), noise percentage doses, and peak levels were also collected. The mean Leq for all band directors was 90.5 dBA. The total accumulated noise percentage dose for all band directors was 77.6% of the maximum allowable daily noise dose under the OSHA standard. The total calculated TWA for all band directors was 88.2% of the maximum allowable daily noise dose under the OSHA standard. The total accumulated noise percentage dose for all band directors was 152.1% of the maximum allowable daily noise dose under the NIOSH standards, and the total calculated TWA for all band directors was 93dBA of the maximum allowable daily noise dose under the NIOSH standard. Multiple regression analysis revealed that the room volume, the level of acoustical treatment and the mean room reverberation time predicted 80% of the variance in sound pressure levels in this study.

  9. N-Acetyl-S-(n-Propyl)-L-Cysteine in Urine from Workers Exposed to 1-Bromopropane in Foam Cushion Spray Adhesives

    Science.gov (United States)

    Hanley, Kevin W.; Petersen, Martin R.; Cheever, Kenneth L.; Luo, Lian

    2009-01-01

    1-Bromopropane (1-BP) has been marketed as an alternative for ozone depleting and other solvents; it is used in aerosol products, adhesives, metal, precision, and electronics cleaning solvents. Mechanisms of toxicity of 1-BP are not fully understood, but it may be a neurological and reproductive toxicant. Sparse exposure information prompted this study using 1-BP air sampling and urinary metabolites. Mercapturic acid conjugates are excreted in urine from 1-BP metabolism involving debromination. Research objectives were to evaluate the utility of urinary N-acetyl-S-(n-propyl)-L-cysteine (AcPrCys) for assessing exposure to 1-BP and compare it to urinary bromide [Br(−)] previously reported for these workers. Forty-eight-hour urine specimens were obtained from 30 workers at two factories where 1-BP spray adhesives were used to construct polyurethane foam seat cushions. Urine specimens were also obtained from 21 unexposed control subjects. All the workers' urine was collected into composite samples representing three time intervals: at work, after work but before bedtime, and upon awakening. Time-weighted average (TWA) geometric mean breathing zone concentrations were 92.4 and 10.5 p.p.m. for spraying and non-spraying jobs, respectively. Urinary AcPrCys showed the same trend as TWA exposures to 1-BP: higher levels were observed for sprayers. Associations of AcPrCys concentrations, adjusted for creatinine, with 1-BP TWA exposure were statistically significant for both sprayers (P < 0.05) and non-sprayers (P < 0.01). Spearman correlation coefficients for AcPrCys and Br(−) analyses determined from the same urine specimens were highly correlated (P < 0.0001). This study confirms that urinary AcPrCys is an important 1-BP metabolite and an effective biomarker for highly exposed foam cushion workers. PMID:19706636

  10. Exposure to MRI-related magnetic fields and vertigo in MRI workers.

    Science.gov (United States)

    Schaap, Kristel; Portengen, Lützen; Kromhout, Hans

    2016-03-01

    Vertigo has been reported by people working around magnetic resonance imaging (MRI) scanners and was found to increase with increasing strength of scanner magnets. This suggests an association with exposure to static magnetic fields (SMF) and/or motion-induced time-varying magnetic fields (TVMF). This study assessed the association between various metrics of shift-long exposure to SMF and TVMF and self-reported vertigo among MRI workers. We analysed 358 shifts from 234 employees at 14 MRI facilities in the Netherlands. Participants used logbooks to report vertigo experienced during the work day at the MRI facility. In addition, personal exposure to SMF and TVMF was measured during the same shifts, using portable magnetic field dosimeters. Vertigo was reported during 22 shifts by 20 participants and was significantly associated with peak and time-weighted average (TWA) metrics of SMF as well as TVMF exposure. Associations were most evident with full-shift TWA TVMF exposure. The probability of vertigo occurrence during a work shift exceeded 5% at peak exposure levels of 409 mT and 477 mT/s and at full-shift TWA levels of 3 mT and 0.6 mT/s. These results confirm the hypothesis that vertigo is associated with exposure to MRI-related SMF and TVMF. Strong correlations between various metrics of shift-long exposure make it difficult to disentangle the effects of SMF and TVMF exposure, or identify the most relevant exposure metric. On the other hand, this also implies that several metrics of shift-long exposure to SMF and TVMF should perform similarly in epidemiological studies on MRI-related vertigo. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  11. An optical spectroscopic study of T Tauri stars. I. Photospheric properties

    Energy Technology Data Exchange (ETDEWEB)

    Herczeg, Gregory J. [Kavli Institute for Astronomy and Astrophysics, Peking University, Yi He Yuan Lu 5, Haidian Qu, Beijing 100871 (China); Hillenbrand, Lynne A. [Caltech, MC105-24, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2014-05-10

    Estimates of the mass and age of young stars from their location in the H-R diagram are limited by not only the typical observational uncertainties that apply to field stars, but also by large systematic uncertainties related to circumstellar phenomena. In this paper, we analyze flux-calibrated optical spectra to measure accurate spectral types and extinctions of 281 nearby T Tauri stars (TTSs). The primary advances in this paper are (1) the incorporation of a simplistic accretion continuum in optical spectral type and extinction measurements calculated over the full optical wavelength range and (2) the uniform analysis of a large sample of stars, many of which are well known and can serve as benchmarks. Comparisons between the non-accreting TTS photospheric templates and stellar photosphere models are used to derive conversions from spectral type to temperature. Differences between spectral types can be subtle and difficult to discern, especially when accounting for accretion and extinction. The spectral types measured here are mostly consistent with spectral types measured over the past decade. However, our new spectral types are one to two subclasses later than literature spectral types for the original members of the TW Hya Association (TWA) and are discrepant with literature values for some well-known members of the Taurus Molecular Cloud. Our extinction measurements are consistent with other optical extinction measurements but are typically 1 mag lower than near-IR measurements, likely the result of methodological differences and the presence of near-IR excesses in most CTTSs. As an illustration of the impact of accretion, spectral type, and extinction uncertainties on the H-R diagrams of young clusters, we find that the resulting luminosity spread of stars in the TWA is 15%-30%. The luminosity spread in the TWA and previously measured for binary stars in Taurus suggests that for a majority of stars, protostellar accretion rates are not large enough to

  12. The Young L Dwarf 2MASS J11193254-1137466 Is a Planetary-mass Binary

    Science.gov (United States)

    Best, William M. J.; Liu, Michael C.; Dupuy, Trent J.; Magnier, Eugene A.

    2017-07-01

    We have discovered that the extremely red, low-gravity L7 dwarf 2MASS J11193254-1137466 is a 0.″14 (3.6 au) binary using Keck laser guide star adaptive optics imaging. 2MASS J11193254-1137466 has previously been identified as a likely member of the TW Hydrae Association (TWA). Using our updated photometric distance and proper motion, a kinematic analysis based on the BANYAN II model gives an 82% probability of TWA membership. At TWA’s 10 ± 3 Myr age and using hot-start evolutionary models, 2MASS J11193254-1137466AB is a pair of {3.7}-0.9+1.2 {M}{Jup} brown dwarfs, making it the lowest-mass binary discovered to date. We estimate an orbital period of {90}-50+80 years. One component is marginally brighter in K band but fainter in J band, making this a probable flux-reversal binary, the first discovered with such a young age. We also imaged the spectrally similar TWA L7 dwarf WISEA J114724.10-204021.3 with Keck and found no sign of binarity. Our evolutionary model-derived {T}{eff} estimate for WISEA J114724.10-204021.3 is ≈230 K higher than for 2MASS J11193254-1137466AB, at odds with the spectral similarity of the two objects. This discrepancy suggests that WISEA J114724.10-204021.3 may actually be a tight binary with masses and temperatures very similar to 2MASS J11193254-1137466AB, or further supporting the idea that near-infrared spectra of young ultracool dwarfs are shaped by factors other than temperature and gravity. 2MASS J11193254-1137466AB will be an essential benchmark for testing evolutionary and atmospheric models in the young planetary-mass regime.

  13. The incidence of post-transplant cancer among kidney transplant recipients is associated with the level of tacrolimus exposure during the first year after transplantation.

    Science.gov (United States)

    Lichtenberg, Shelly; Rahamimov, Ruth; Green, Hefziba; Fox, Benjamin D; Mor, Eytan; Gafter, Uzi; Chagnac, Avry; Rozen-Zvi, Benaya

    2017-07-01

    Immunosuppressive therapy plays a major role in the development of post-transplant cancer. In this nested case-control study of kidney transplant recipients (KTRs), we investigated whether the incidence of post-transplant cancer is associated with the level of tacrolimus exposure over time. We screened the Rabin Medical Center database for adults who received kidney transplants between 2001 and 2014 and developed post-transplant cancer (excluding basal and squamous cell skin cancers). They were matched against KTRs without cancer. All patients received a maintenance immunosuppressive treatment with tacrolimus, mycophenolate mofetil and corticosteroids. The degree of exposure to tacrolimus was estimated as the time-weighted average (tTWA) value of tacrolimus blood levels. The tTWA was calculated as the area under the curve divided by time at 1, 6, and 12 months after transplantation and at time of cancer diagnosis. Thirty-two cases were matched against 64 controls. tTWA values above 11 ng/mL at 6 and 12 months after transplantation were associated with odds ratio (OR) of 3.1 (95% CI 1.1-9) and 11.7 (95% CI = 1.3-106), respectively, for post-transplant cancer; and with OR of 5.2 (95% CI 1.3-20.5) and 14.1 (95% CI = 1.5-134.3), respectively, for cancer diagnosed more than 3 years after transplantation. Exposure to a tacrolimus time-weighted average level above 11 ng/mL at 6 or 12 months after kidney transplantation is associated with an increased risk of developing cancer.

  14. The Cumulative Lifting Index (CULI) for the Revised NIOSH Lifting Equation: Quantifying Risk for Workers With Job Rotation.

    Science.gov (United States)

    Garg, Arun; Kapellusch, Jay M

    2016-08-01

    The objectives were to: (a) develop a continuous frequency multiplier (FM) for the Revised NIOSH Lifting Equation (RNLE) as a function of lifting frequency and duration of a lifting task, and (b) describe the Cumulative Lifting Index (CULI), a methodology for estimating physical exposure to workers with job rotation. The existing FM for the RNLE (FME) does not differentiate between task duration >2 hr and <8 hr, which makes quantifying physical exposure to workers with job rotation difficult and presents challenges to job designers. Using the existing FMs for 1, 2, and 8 hr of task durations, we developed a continuous FM (FMP) that extends to 12 hr per day. We simulated 157,500 jobs consisting of two tasks each and, using different combinations of Frequency Independent Lifting Index, lifting frequency and duration of lifting. Biomechanical stresses were estimated using the CULI, time-weighted average (TWA), and peak exposure. The median difference between FME and FMP was ±1% (range: 0%-15%). Compared to CULI, TWA underestimated risk of low-back pain (LBP) for 18% to 30% of jobs, and peak exposure for an assumed 8-hr work shift overestimated risk of LBP for 20% to 25% of jobs. Peak task exposure showed 90% agreement with CULI but ignored one of two tasks. The CULI partially addressed the underestimation of physical exposure using the TWA approach and overestimation of exposure using the peak-exposure approach. The proposed FM and CULI may provide more accurate physical exposure estimates, and therefore estimated risk of LBP, for workers with job rotation. © 2016, Human Factors and Ergonomics Society.

  15. Titanium dioxide nanoparticles: occupational exposure assessment in the photocatalytic paving production

    International Nuclear Information System (INIS)

    Spinazzè, Andrea; Cattaneo, Andrea; Limonta, Marina; Bollati, Valentina; Bertazzi, Pier Alberto; Cavallo, Domenico M.

    2016-01-01

    Limited data are available regarding occupational exposure assessment to nano-sized titanium dioxide (nano-TiO_2). The objective of this study is to assess the occupational exposure of workers engaged in the application of nano-TiO_2 onto concrete building materials, by means of a multi-metric approach (mean diameter, number, mass and surface area concentrations). The measurement design consists of the combined use of (i) direct-reading instruments to evaluate the total particle number concentrations relative to the background concentration and the mean size-dependent characteristics of particles (mean diameter and surface area concentration) and to estimate the 8-h time-weighted average (8-h TWA) exposure to nano-TiO_2 for workers involved in different working tasks; and (ii) filter-based air sampling, used for the determination of size-resolved particle mass concentrations. A further estimation was performed to obtain the mean 8-h TWA exposure values expressed as mass concentrations (µg nano-TiO_2/m"3). The multi-metric characterization of occupational exposure to nano-TiO_2 was significantly different both for different work environments and for each work task. Generally, workers were exposed to engineered nanoparticles (ENPs; <100 nm) mean levels lower than the recommended reference values and proposed occupational exposure limits (40,000 particle/cm"3; 300 µg/m"3) and relevant exposures to peak concentration were not likely to be expected. The estimated 8-h TWA exposure showed differences between the unexposed and exposed subjects. For these last, further differences were defined between operators involved in different work tasks. This study provides information on nano-TiO_2 number and mass concentration, size distribution, particles diameter and surface area concentrations, which were used to obtain work shift-averaged exposures.

  16. Revisiting TW Hydrae in light of new astrometric data

    Science.gov (United States)

    Teixeira, R.; Ducourant, C.; Galli, P. A. B.; Le Campion, J. F.; Zuckerman, B.; Krone-Martins, A. G. O.; Chauvin, G.; Song, I.

    2014-10-01

    Our efforts in the present work focused mainly on refining and improving the previous description and understanding of the stellar association TW Hydrae (TWA) including a very detailed membership analysis and its dynamical and evolutionary age.To achieve our objectives in a fully reliable way we take advantage of our own astrometric measurements (Ducourant et al. 2013) performed with NTT/EFOSC2 - ESO (La Silla - Chile) spread over three years (2007 - 2010) and of those published in the literature.A very detailed membership analysis based on the convergent point strategy as developed by our team (Galli et al. 2012, 2013) allowed us to define a consistent kinematic group containing 31 stars among the 44 proposed as TWA member in the literature. Assuming that our sample of stars may be contaminated by non-members and to get rid of the particular influence of each star we applied a Jacknife resampling technique generating 2000 random lists of 13 stars taken from our 16 stars and calculated for each the epoch of convergence when the radius is minimum. The mean of the epochs obtained and the dispersion about the mean give a dynamical age of 7.5± 0.7 Myr for the association that is in good agreement with the previous traceback age (De La Reza et al. 2006). We also estimated age for TWA moving group members from pre-main sequence evolutionary models (Siess et al. 2000) and find a mean age of 7.4± 1.2 Myr. These results show that the dynamical age of the association obtained via the traceback technique and the average age derived from theoretical evolutionary models are in good agreement.

  17. Titanium dioxide nanoparticles: occupational exposure assessment in the photocatalytic paving production

    Energy Technology Data Exchange (ETDEWEB)

    Spinazzè, Andrea, E-mail: andrea.spinazze@uninsubria.it; Cattaneo, Andrea; Limonta, Marina [Università degli studi dell’Insubria, Dipartimento di Scienza e Alta Tecnologia (Italy); Bollati, Valentina; Bertazzi, Pier Alberto [Università degli Studi di Milano, EPIGET-Epidemiology, Epigenetics and Toxicology Lab, Dipartimento di Scienze Cliniche e di Comunità (Italy); Cavallo, Domenico M. [Università degli studi dell’Insubria, Dipartimento di Scienza e Alta Tecnologia (Italy)

    2016-06-15

    Limited data are available regarding occupational exposure assessment to nano-sized titanium dioxide (nano-TiO{sub 2}). The objective of this study is to assess the occupational exposure of workers engaged in the application of nano-TiO{sub 2} onto concrete building materials, by means of a multi-metric approach (mean diameter, number, mass and surface area concentrations). The measurement design consists of the combined use of (i) direct-reading instruments to evaluate the total particle number concentrations relative to the background concentration and the mean size-dependent characteristics of particles (mean diameter and surface area concentration) and to estimate the 8-h time-weighted average (8-h TWA) exposure to nano-TiO{sub 2} for workers involved in different working tasks; and (ii) filter-based air sampling, used for the determination of size-resolved particle mass concentrations. A further estimation was performed to obtain the mean 8-h TWA exposure values expressed as mass concentrations (µg nano-TiO{sub 2}/m{sup 3}). The multi-metric characterization of occupational exposure to nano-TiO{sub 2} was significantly different both for different work environments and for each work task. Generally, workers were exposed to engineered nanoparticles (ENPs; <100 nm) mean levels lower than the recommended reference values and proposed occupational exposure limits (40,000 particle/cm{sup 3}; 300 µg/m{sup 3}) and relevant exposures to peak concentration were not likely to be expected. The estimated 8-h TWA exposure showed differences between the unexposed and exposed subjects. For these last, further differences were defined between operators involved in different work tasks. This study provides information on nano-TiO{sub 2} number and mass concentration, size distribution, particles diameter and surface area concentrations, which were used to obtain work shift-averaged exposures.

  18. The Dynamic Characteristics of Silver Nanoparticles in Physiological Fluids: Toxicological Implications

    Science.gov (United States)

    2014-11-19

    were received dispersed in solution from Dr. Dan Goia’s laboratory at Clarkson University, Potsdam , NY. For these Ag NPs, the coating was continuous and...amount of Ag inhaled in a standard worker over an 8 h work day into a single administered dose, normalized by respiratory rate (20 000 mL/min...conversion) (TLV TWA) (exposure time) (particle lung deposition efficiency) = × × × × × −(20 000 mL/min) (1 10 m /mL) (0.01 mg/m ) (480 min / day ) 0.35 6

  19. Programmatic Life Cycle Environmental Assessment for Smoke/Obscurants. Volume 1. Fog Oil, Diesel Fuels, and Polyethylene Glycol (PEG 200)

    Science.gov (United States)

    1983-07-01

    distances using TLV on these models requires conversion from concentration to dosage. The TWA (time weighted averae) for healthy adult humans exposed to oil...diseases. Chronic industrial exposures of oils and oil mists have been implicated in causing dermatosis (SGF No. 1) and dermatosis plus tumors of skin...mg/I No. 2 2-Day LCo Is Quahaug larvae fuel oil dissolved in water Exposure to 0.53 mg/l No. 10-Day LCo0 2 fuel oil dissolved in water Young adult

  20. Manganese Fractionation Using a Sequential Extraction Method to Evaluate Welders' Shielded Metal Arc Welding Exposures During Construction Projects in Oil Refineries.

    Science.gov (United States)

    Hanley, Kevin W; Andrews, Ronnee; Bertke, Steven; Ashley, Kevin

    2015-01-01

    The National Institute for Occupational Safety and Health has conducted an occupational exposure assessment study of manganese (Mn) in welding fume of construction workers rebuilding tanks, piping, and process equipment at two oil refineries. The objective of this study was to evaluate exposures to different Mn fractions using a sequential extraction procedure. Seventy-two worker-days were monitored for either total or respirable Mn during stick welding and associated activities both within and outside of confined spaces. The samples were analyzed using an experimental method to separate different Mn fractions by valence states based on selective chemical solubility. The full-shift total particulate Mn time-weighted average (TWA) breathing zone concentrations ranged from 0.013-29 for soluble Mn in a mild ammonium acetate solution; from 0.26-250 for Mn(0,2+) in acetic acid; from non-detectable (ND) - 350 for Mn(3+,4+) in hydroxylamine-hydrochloride; and from ND - 39 micrograms per cubic meter (μg/m(3)) for insoluble Mn fractions in hydrochloric and nitric acid. The summation of all Mn fractions in total particulate TWA ranged from 0.52-470 μg/m(3). The range of respirable particulate Mn TWA concentrations were from 0.20-28 for soluble Mn; from 1.4-270 for Mn(0,2+); from 0.49-150 for Mn(3+,4+); from ND - 100 for insoluble Mn; and from 2.0-490 μg/m(3) for Mn (sum of fractions). For all jobs combined, total particulate TWA GM concentrations of the Mn(sum) were 99 (GSD = 3.35) and 8.7 (GSD = 3.54) μg/m(3) for workers inside and outside of confined spaces; respirable Mn also showed much higher levels for welders within confined spaces. Regardless of particle size and confined space work status, Mn(0,2+) fraction was the most abundant followed by Mn(3+,4+) fraction, typically >50% and ∼30-40% of Mn(sum), respectively. Eighteen welders' exposures exceeded the ACGIH Threshold Limit Values for total Mn (100 μg/m(3)) and 25 exceeded the recently adopted respirable

  1. Benzene exposure in a Japanese petroleum refinery.

    Science.gov (United States)

    Kawai, T; Yamaoka, K; Uchida, Y; Ikeda, M

    1990-07-01

    Time-weighted average (TWA) intensity of exposure of workers to benzene vapor during a shift was monitored by diffusive sampling technique in a Japanese petroleum refinery. The subjects monitored (83 in total) included refinery operators, laboratory personnel and tanker-loading workers. The results showed that the time-weighted average exposures are well below 1 ppm in most cases. The highest exposure was recorded in 1 case involved in bulk loading of tanker ships, in which exposure of over 1 ppm might take place depending on operational conditions. The observation was generally in agreement with levels previously reported.

  2. The Evaluation of Relationship between Spirometric Disorders and Methyl methacrylate in Dental Laboratories Personnel

    Directory of Open Access Journals (Sweden)

    E. Nadi

    2010-04-01

    Full Text Available Introduction & Objective: Methyl methacrylate (MMA, as a monomer of acrylic resin that has a wide variety of usages in denture fabrication, is considered as an air pollution indicator in the laboratories. Occupational exposure to these compound vapors can cause respiratory hypersensitivity, occupational asthma, eye and skin irritation and Allergic Contact Dermatitis (ACD. Therefore control of MMA exposure may promote the personnel’s health. The aim of this study was to determine the relationship between spirometric disorders and methyl methacrylate in dental laboratories personnel.. Materials & Methods: In this case control study, exposure of time-weighted average (TWA and short-term exposure level (STEL were measured with MMA vapors in 39 randomly selected male employee (case group in 25 denture fabrication laboratories in Hamadan city. The air samples were collected by sorbent tubes containing chromosorb (XAD2( and analyzed by gas chromatograph equipped with FID detector based on NIOSH method. In addition 30 men whitout occupational exposure to air pollutants (control group were selected to compare the variation of spirometric parameters. Spirometric parameters of the case and control groups such as FVC, FEV1, FEV1/FVC and FEF25-75 were measured by Vitalograph spirometer (model: 2120 on ATS method, after the standard questionnaire of respiratory diseases had been completed during an interview and medical examination..Results: The mean of MMA concentration was 132.87 ± 220.67 ppm for STEL and 1.95 ± 3.59 ppm for TWA.The relationship between MMA concentration in the STEL and TWA exposures was significant (P<0.05 and the relationship between MMA concentration and ventilation was significant just for STEL. In this study no relationship between MMA concentration and spirometric parameters in both STEL and TWA exposures was found. Also there was no significant difference between spirometric parameters of the case group and normal values of the

  3. Fabric protectors. Part II - Propane, 1,1,1-trichloroethane, and petroleum distillates levels in air after application of fabric protectors.

    Science.gov (United States)

    Otson, R; Williams, D T; Bothwell, P D

    1984-01-01

    Propane, 1,1,1-trichloroethane, and petroleum distillates levels in air which were generated during the use of aerosol type fabric protectors were monitored by means of the NIOSH charcoal tube, a glass bulb grab sampling, and the GASBADGE passive device techniques. Although 1982 ACGIH TLV-STEL were readily exceeded in an unventilated test room, when fabric was sprayed with 450 g of fabric protector in an unconfined area within a home the generated vapors quickly dispersed and STEL and 8-hour TWA-TLV were not exceeded.

  4. La noción del tiempo en la cultura maya prehispánica

    Directory of Open Access Journals (Sweden)

    Alexander Wolfgang Voss

    2015-07-01

    Full Text Available La concepción del tiempo de los mayas prehispánicos se estudia mediante el análisis epigráfico y filológico de textos jeroglíficos bajo los planteamientos teóricos de la escuela italiana de historia de las religiones. Los datos indican que el tiempo es animado y formado por unidades discretas tangibles que se representan con un calendario de 365 días. Las características de cada día son fijadas por un oráculo de suertes de 260 unidades que es proyectado sobre el tiempo. El tiempo y el oráculo son pensados como dioses que se alternan en un orden y no como una magnitud física abstracta.

  5. Feeding habits of Carabidae (Coleoptera associated with herbaceous plants and the phenology of coloured cotton

    Directory of Open Access Journals (Sweden)

    Danilo Henrique da Matta

    2017-04-01

    Full Text Available The carabids (Coleoptera: Carabidae are recognized as polyphagous predators and important natural enemies of insect pests. However, little is known about the feeding habits of these beetles. In this work, we determine the types of food content in the digestive tracts of nine species of Carabidae associated with herbaceous plants and different growth stages of coloured cotton. The food contents were evaluated for beetles associated with the coloured cotton cv. BRS verde, Gossypium hirsutum L. latifolium Hutch., adjacent to weed plants and the flowering herbaceous plants (FHPs Lobularia maritima (L., Tagetes erecta L., and Fagopyrum esculentum Moench. The digestive tract analysis indicated various types of diets and related arthropods for Abaris basistriata, Galerita brasiliensis, Scarites sp., Selenophorus alternans, Selenophorus discopunctatus and Tetracha brasiliensis. The carabids were considered to be polyphagous predators, feeding on different types of prey.

  6. An Unusual Case of Alternating Ventricular Morphology on the 12-Lead Electrocardiogram.

    Science.gov (United States)

    Sammon, Maura; Dawood, Alveena; Beaudoin, Scott; Harrigan, Richard A

    2017-03-01

    One of the principal tasks of an emergency physician is identifying potentially life-threatening conditions in the undifferentiated patient; cardiac dysrhythmia is an example of such a condition. A systematic approach to a patient with atypical dysrhythmia enables proper identification of such-life threatening conditions. We describe a 31-year-old man presenting to the emergency department with an undifferentiated dysrhythmia after naloxone reversal of an opiate overdose. A systematic approach to the electrocardiogram led to the rare diagnosis of Wolff-Parkinson-White (WPW) alternans. We review the differential diagnosis of this dysrhythmia and the initial evaluation of a patient with the WPW pattern present on their electrocardiogram. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Emergency physicians should be prepared to use a systematic approach to an undifferentiated dysrhythmia to identify potentially life-threatening conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. The importance of hormonal circadian rhythms in daily feeding patterns: An illustration with simulated pigs.

    Science.gov (United States)

    Boumans, Iris J M M; de Boer, Imke J M; Hofstede, Gert Jan; la Fleur, Susanne E; Bokkers, Eddie A M

    2017-07-01

    The interaction between hormonal circadian rhythms and feeding behaviour is not well understood. This study aimed to deepen our understanding of mechanisms underlying circadian feeding behaviour in animals, using pigs, Sus scrofa, as a case study. Pigs show an alternans feeding pattern, that is, a small peak of feed intake at the beginning of the day and a larger peak at the end of the day. We simulated the feeding behaviour of pigs over a 24h period. The simulation model contained mechanisms that regulate feeding behaviour of animals, including: processing of feed in the gastrointestinal tract, fluctuation in energy balance, circadian rhythms of melatonin and cortisol and motivational decision-making. From the interactions between these various processes, feeding patterns (e.g. feed intake, meal frequency, feeding rate) emerge. These feeding patterns, as well as patterns for the underlying mechanisms (e.g. energy expenditure), fitted empirical data well, indicating that our model contains relevant mechanisms. The circadian rhythms of cortisol and melatonin explained the alternans pattern of feeding in pigs. Additionally, the timing and amplitude of cortisol peaks affected the diurnal and nocturnal peaks in feed intake. Furthermore, our results suggest that circadian rhythms of other hormones, such as leptin and ghrelin, are less important in circadian regulation of feeding behaviour than previously thought. These results are relevant to animal species with a metabolic and endocrine system similar to that of pigs, such as humans. Moreover, the modelling approach to understand feeding behaviour can be applied to other animal species. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Long-term cardiac memory in canine heart is associated with the evolution of a transmural repolarization gradient

    NARCIS (Netherlands)

    Coronel, Ruben; Opthof, Tobias; Plotnikov, Alexei N.; Wilms-Schopman, Francien J. G.; Shlapakova, Iryna N.; Danilo, Peter; Sosunov, Eugene A.; Anyukhovsky, Evgeny P.; Janse, Michiel J.; Rosen, Michael R.

    2007-01-01

    OBJECTIVE: The contribution of regional electrophysiologic heterogeneity to the T-wave changes of long-term cardiac memory (CM) is not known. We mapped activation and repolarization in dogs after induction of CM and in sham animals. METHODS AND RESULTS: CM was induced by three weeks of AV-sequential

  9. Feasibility and accuracy of a new mobile electrocardiography device, ER-2000®, in the diagnosis of arrhythmia

    Directory of Open Access Journals (Sweden)

    Yae Min Park

    2015-08-01

    Conclusions: A rhythm strip obtained using ER-2000® is accurate in diagnosing arrhythmia, despite some differences in the detailed morphology of the QRS and T-wave, and the pacing spike compared to those obtained by the 12-lead ECG.

  10. Clinical characteristics in genetically distinct forms of the congenital long QT syndrome

    International Nuclear Information System (INIS)

    Kawahara, Yosuke; Sawayama, Toshitami; Samukawa, Masanobu; Nezuo, Shoso; Tanaka, Junji; Suetsuna, Ryoji; Kamiyama, Norio

    1998-01-01

    The clinical characteristics in genetically distinct forms of the congenital long QT syndrome (LQTs) were examined on the balance of bilateral sympathetic nerves, and ECG findings. The subjects (mean: 19.4 years old) were three genetically distinct forms of LQTs, including 3 patients in A-family (the high risk family with sudden death), 2 patients in B-family and 3 patients in C-family. All patients met the standard diagnostic criteria according to Schwartz. As the index of the balance of bilateral sympathetic nerves, the dissociation of Tl and MIBG uptake (D) was examined and the radioactivity ratio (the A/L ratio) of anteroseptal wall to posterolateral wall was calculated. The T-wave patterns of ECG and the situation at syncope were examined. In A-family, all 3 patients showed the lowered A/L ratio, D(+), and similar T-wave patterns in ECG. The syndrome developed at exercise, and their QTc extended at exercise. In B-family, all 2 patients showed normal A/L ratio and long T-wave at QT onset, and their QTc shortened at exercise. All patients had developed syncope at rest. In C-family, all 3 patients showed a little decrease of A/L ratio and similar T-wave patterns. Their QTc extended at exercise. These results suggest that the characteristics of the sympathetic nerve balance, ECG wave patterns and the syndrome may depend on each family. (K.H.)

  11. Waves in the seas

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J

    , steep nonsymmetric cnoidal waves, solitons and random waves. They have different properties too. Any wave form has a wave period (T), wave height (H) and speed (C) which depends on T. Still another type of waves are breaking waves near a coast...

  12. Comparative study of T-amplitude features for fitness monitoring using the ePatch® ECG recorder

    DEFF Research Database (Denmark)

    Thorpe, Julia Rosemary; Saida, Trine; Mehlsen, Jesper

    2014-01-01

    This study investigates ECG features, focusing on T-wave amplitude, from a wearable ECG device as a potential method for fitness monitoring in exercise rehabilitation. An automatic T-peak detection algorithm is presented that uses local baseline detection to overcome baseline drift without the need...

  13. Superconducting magnetocardiograph

    Energy Technology Data Exchange (ETDEWEB)

    Fodel, V

    1982-06-01

    The first SQUID magnetocardiograph developed in the Soviet Union (at the Neutron Physics Laboratory of the Dubna Nuclear Research Institute) is briefly described, and its advantages in relation to conventional cardiographs are discussed. The magnetocardiogram, obtained using this instrument, of a healthy 35-year-old man is presented, and is found to clearly delineate the QRS complex and the T-wave.

  14. Electrocardiographic Changes and Troponin T Levels in Children ...

    African Journals Online (AJOL)

    2017-05-22

    May 22, 2017 ... subjects and controls; it was recorded using a portable segment depression, and elevation compared to children without anemia. This is consistent with myocardial ischemia. The ECG changes of T wave abnormality, ST segment depression, and elevation have been documented in patients with malaria, ...

  15. THE ELECTROCARDIOGRAM IN CHRONIC BRONCmTIS AND ...

    African Journals Online (AJOL)

    1971-02-20

    Feb 20, 1971 ... block, and the degree of clockwise rotation. The position of T wave inversion in the chest leads was noted. The. ECG findings for P wave axis and shape and QRS axis were .mbdivided, using the criteria of Spodick et al.' Single-peaked P waves were termed P pulmonale (ampli- tude >0'24 mY) or Gothic P ...

  16. Assessment of residual tissue viability by exercise testing in recent myocardial infarction: comparison of the electrocardiogram and myocardial perfusion scintigraphy.

    Science.gov (United States)

    Margonato, A; Ballarotto, C; Bonetti, F; Cappelletti, A; Sciammarella, M; Cianflone, D; Chierchia, S L

    1992-04-01

    The assessment of residual myocardial viability in infarcted areas is relevant for subsequent management and prognosis but requires expensive technology. To evaluate the possibility that simple, easily obtainable clinical markers may detect the presence of within-infarct viable tissue, the significance of exercise-induced ST elevation occurring in leads exploring the area of a recent Q wave myocardial infarction was assessed. Twenty-five patients with recent (less than 6 months) myocardial infarction were studied. All had angiographically documented coronary artery disease, diagnostic Q waves (n = 24) or negative T waves (n = 25) on the rest 12-lead electrocardiogram and exhibited during exercise greater than or equal to 1.5 mm ST segment elevation (n = 17) or isolated T wave pseudonormalization (n = 8) in the infarct-related leads. ST-T wave changes were reproduced in all patients during thallium-201 exercise myocardial scintigraphy. A fixed perfusion defect was observed in 24 of the 25 patients. A reversible defect was seen in 16 (94%) of 17 patients who exhibited transient ST elevation during exercise but in only 4 (50%) of the 8 patients who had only T wave pseudonormalization. In conclusion, in patients with recent myocardial infarction, analysis of simple ST segment variables obtained during exercise testing may allow a first-line discrimination of those who may potentially benefit from a revascularization procedure.

  17. Prevalence of electrocardiographic ST-T changes during acute ischemic stroke in patients without known ischemic heart disease

    DEFF Research Database (Denmark)

    Jensen, Jesper K; Bak, Søren; Flemming Høilund-Carlsen, Poul

    2008-01-01

    We evaluated characteristics and prevalence of ST-segment depression and/or T-wave inversion in the resting electrocardiogram of 244 consecutive patients with acute ischemic stroke, but without ischemic heart disease. The prevalence of ST-T changes ranged from 13% to 16% and this is what to expect...

  18. Thiolated polymers: evaluation of their potential as dermoadhesive excipients.

    Science.gov (United States)

    Grießinger, Julia Anita; Bonengel, Sonja; Partenhauser, Alexandra; Ijaz, Muhammad; Bernkop-Schnürch, Andreas

    2017-02-01

    The objective of this study was to evaluate and compare four different thiolated polymers regarding their dermoadhesive potential. Therefore, three hydrophilic polymers (poly(acrylic acid), Carbopol 971 and carboxymethylcellulose) and a lipophilic polymer (silicone oil) were chosen to generate thiolated polymers followed by characterization. The total work of adhesion (TWA) and the maximum detachment force (MDF) of formulations containing modified and unmodified polymers were investigated on skin obtained from pig ears using a tensile sandwich technique. The synthesis of thiolated polymers provided 564 µmol, 1079 µmol, 482 µmol and 217 µmol thiol groups per gram poly(acrylic acid), Carbopol 971, carboxymethylcellulose and silicone oil, respectively. Hydrogels containing poly(acrylic acid)-cysteine, Carbopol 971-cysteine, and carboxymethylcellulose-cysteamine exhibited a 6-fold, 25-fold and 9-fold prolonged adhesion on porcine skin than the hydrogel formulations prepared from the corresponding unmodified polymers, respectively. Furthermore, thiolation of silicone oil with thioglycolic acid led to a 5-fold improvement in adhesion compared to the unmodified silicone oil. A comparison between the four thiolated polymer formulations showed a clear correlation between the amount of coupled thiol groups and the TWA. According to these results thiomers might also be useful excipients to provide a prolonged dermal resistance time of various formulations.

  19. Lithium in Drinking Water and Incidence of Suicide: A Nationwide Individual-Level Cohort Study with 22 Years of Follow-Up.

    Science.gov (United States)

    Knudsen, Nikoline N; Schullehner, Jörg; Hansen, Birgitte; Jørgensen, Lisbeth F; Kristiansen, Søren M; Voutchkova, Denitza D; Gerds, Thomas A; Andersen, Per K; Bihrmann, Kristine; Grønbæk, Morten; Kessing, Lars V; Ersbøll, Annette K

    2017-06-10

    Suicide is a major public health concern. High-dose lithium is used to stabilize mood and prevent suicide in patients with affective disorders. Lithium occurs naturally in drinking water worldwide in much lower doses, but with large geographical variation. Several studies conducted at an aggregate level have suggested an association between lithium in drinking water and a reduced risk of suicide; however, a causal relation is uncertain. Individual-level register-based data on the entire Danish adult population (3.7 million individuals) from 1991 to 2012 were linked with a moving five-year time-weighted average (TWA) lithium exposure level from drinking water hypothesizing an inverse relationship. The mean lithium level was 11.6 μg/L ranging from 0.6 to 30.7 μg/L. The suicide rate decreased from 29.7 per 100,000 person-years at risk in 1991 to 18.4 per 100,000 person-years in 2012. We found no significant indication of an association between increasing five-year TWA lithium exposure level and decreasing suicide rate. The comprehensiveness of using individual-level data and spatial analyses with 22 years of follow-up makes a pronounced contribution to previous findings. Our findings demonstrate that there does not seem to be a protective effect of exposure to lithium on the incidence of suicide with levels below 31 μg/L in drinking water.

  20. Evaluation of occupational exposure to static magnetic field in a chloralkali plant

    Directory of Open Access Journals (Sweden)

    AR Coobineh

    2005-10-01

    Full Text Available Background and Aims: An observational cross sectional study was conducted to determine iflong term exposure to static magnetic fields could be related to findings of medical examinations.Method: Health data were obtained for 20 workers who spent a major portion of their workdaysin the magnetic fields produced by the direct current through large electrolytic cells. These datawere compared to those of a control group of 21 workers. Intensity of magnetic fields weremeasured in the cell room and the Time weighted Average (TWA exposure to magnetic field wascalculated for each job classification.Results: Maximum and minimum intensities in mTwere found to be 16.99 and 0.46, respectively,which were well below the permissible level. Maximum TWAexposure to magnetic field wasfound to be 47.59 mTWhich were observed. Comparing the ECG, EEG, blood Pressure and pulseratesbetween the two groups showed no statistically significant differences. Clinical findingshowed that fatigue and nervousness complain were be higher in the case group and weresignificantly different between the two groups.Conclusion: We did not see statistical significant differences between case and control groups inECG, EEG, blood pressure and pulse-rates. We have seen statistically differences in the fatigue(P<0.01 and nervousness (P<0.01 complain of these two groups. We suggest that it may benecessary to choose a value of than 60 mT (TLV-TWA, so that the complains of fatigue andnervousness will be reduce.

  1. Post-Kemron, Uganda demands proof of the "Mariandina" drug.

    Science.gov (United States)

    1996-12-01

    An ethical review committee consisting of medical scientists, social scientists, and lawyers has been established by the Ugandan government to oversee individuals and institutions conducting biomedical research. The research of Professor Sali, who produced and marketed Mariandina as a cure for acquired immunodeficiency syndrome (AIDS), is not recognized, according to Dr. Jeremiah Twa-twa, Registrar of the National Medical Council. Professor Sali had been given six months to produce an acceptable protocol, with controls, that demonstrated the efficacy of the drug. He had stated previously that his patients received a minimum of six tablets daily of Mariandina A, B, or J; thousands are said to have been treated. Professor Sali, who returned to Uganda in 1990 with a 100,000-pound loan to produce the drug, advised his patients to sell everything they owned in order to pay for their treatment, according to Major Ruranga Rubaramira (head of a joint clinical council). The Uganda AIDS Commission is also considering the use of herbs in the treatment of AIDS; nine Western-trained researchers are collaborating with herbalists in studies that have shown promising results. Dr. Donna Kabatesi, who heads a clinic that uses both herbs and Western medicine in the treatment of AIDS patients at Mulago hospital, believes herbs are equally effective for some purposes.

  2. [Study of the effect of occupational exposure to glyphosate on hepatorenal function].

    Science.gov (United States)

    Zhang, F; Pan, L P; Ding, E M; Ge, Q J; Zhang, Z H; Xu, J N; Zhang, L; Zhu, B L

    2017-07-06

    Objective: To explore the effect of occupational exposure to glyphosate on hepatorenal function. Methods: 526 workers who were occupationally exposed to glyphosate from 5 glyphosate-producing factories were selected as cases; and another 442 administrative staffs who were not exposed to glyphosate were selected as controls from April to November, 2014. All the subjects accepted occupational health examination. The concentration level of glyphosate in the air of workshop was detected and the time weighted average concentration (TWA) was calculated. And analyze the difference of hepatorenal fuction between case group and control group. Result: The age of the subjects in the case and control groups were separately (35.6±10.3), (34.3±9.7) years old, with the length of working for (6.5±5.7), (7.7±6.8) years. The TWA of glyphosate in the case group was between Glyphosate can affect the hepatic and renal function among occupational exposure population, and there was an association between the effect and the exposure dose.

  3. Development of a passive sampler based on a polymer inclusion membrane for total ammonia monitoring in freshwaters.

    Science.gov (United States)

    Almeida, M Inês G S; Silva, Adélia M L; Coleman, Rhys A; Pettigrove, Vincent J; Cattrall, Robert W; Kolev, Spas D

    2016-05-01

    A passive sampler for determining the time-weighted average total ammonia (i.e. molecular ammonia and the ammonium cation) concentration (C TWA) in freshwaters, which incorporated a polymer inclusion membrane (PIM) as a semi-permeable barrier separating the aqueous source solution from the receiving solution (i.e. 0.8 mol L(-1) HCl), was developed for the first time. The PIM was composed of dinonylnaphthalene sulfonic acid (DNNS) as a carrier, poly (vinyl chloride) (PVC) as a base polymer and 1-tetradecanol as a modifier. Its optimal composition was found to be 35 wt% commercial DNNS, 55 wt% PVC and 10 wt% 1-tetradecanol. The effect of environmental variables such as the water matrix, pH and temperature were also studied using synthetic freshwaters. The passive sampler was calibrated under laboratory conditions using synthetic freshwaters and exhibited a linear response within the concentration range 0.59-2.8 mg L(-1) NH4(+) (0.46-2.1 mg N L(-1)) at 20 °C. The performance of the sampler was further investigated under field conditions over 7 days. A strong correlation between spot sampling and passive sampling was achieved, thus providing a proof-of-concept for the passive sampler for reliably measuring the C(TWA) of total ammonia in freshwaters, which can be used as an indicator in tracking sources of faecal contamination in stormwater drains.

  4. Characterization of airborne BTEX exposures during use of lawnmowers and trimmers.

    Science.gov (United States)

    Avens, Heather J; Maskrey, Joshua R; Insley, Allison L; Unice, Kenneth M; Reid, Rachel C D; Sahmel, Jennifer

    2018-02-08

    Few studies have evaluated airborne exposures to benzene, toluene, ethylbenzene, and xylenes (BTEX) during operation of two-stroke and four-stroke small engines, such as those in lawn maintenance equipment. Full-shift, 8-hour personal samples were collected during a simulation study to characterize yard maintenance activities including mowing, trimming, and fueling. Short-term, 15-minute personal samples were collected to separately evaluate mowing and trimming exposures. Mean 8-hour time weighted average (TWA) BTEX concentrations were 2.3, 5.8, 0.91, and 4.6 ppb, respectively (n = 2). Mean 15-minute TWA BTEX concentrations were 1.6, 1.8, 0.22, and 1.3 ppb, respectively, during mowing and 1.2, 3.6, 0.68, and 3.3 ppb, respectively, during trimming (n = 3 per task). Measured BTEX concentrations during fueling were 20-110, 61-310, 8-41, and 40-203 ppb, respectively (n = 2, duration 2-3 minutes). These exposure concentrations were well below applicable US occupational exposure limits.

  5. Assessment of Occupational Noise Exposure among Groundskeepers in North Carolina Public Universities

    Directory of Open Access Journals (Sweden)

    Jo Anne G. Balanay

    2016-01-01

    Full Text Available Groundskeepers may have increased risk to noise-induced hearing loss due to the performance of excessively noisy tasks. This study assessed the exposure of groundskeepers to noise in multiple universities and determined the association between noise exposure and variables (ie, university, month, tool used. Personal noise exposures were monitored during the work shift using noise dosimetry. A sound level meter was used to measure the maximum sound pressure levels from groundskeeping equipment. The mean Occupational Safety and Health Administration (OSHA and National Institute for Occupational Safety and Health (NIOSH time-weighted average (TWA noise exposures were 83.0 ± 9.6 and 88.0 ± 6.7 dBA, respectively. About 52% of the OSHA TWAs and 77% of the NIOSH TWAs exceeded 85 dBA. Riding mower use was associated with high TWA noise exposures and with having OSHA TWAs exceeding 85 and 90 dBA. The maximum sound pressure levels of equipment and tools measured ranged from 76 to 109 dBA, 82% of which were >85 dBA. These findings support that groundskeepers have excessive noise exposures, which may be effectively reduced through careful scheduling of the use of noisy equipment/tools.

  6. A PREDICTIVE STUDY: CARBON MONOXIDE EMISSION MODELING AT A SIGNALIZED INTERSECTION

    Directory of Open Access Journals (Sweden)

    FREDDY WEE LIANG KHO

    2014-02-01

    Full Text Available CAL3QHC dispersion model was used to predict the present and future carbonmonoxide (CO levels at a busy signalized intersection. This study attempted to identify CO “hot-spots” at nearby areas of the intersection during typical A.M. and P.M. peak hours. The CO concentration “hot-spots” had been identified at 101 Commercial Park and the simulated maximum 1-hour Time-Weighted Average (1-h TWA ground level CO concentrations of 18.3 ppm and 18.6 ppm had been observed during A.M. and P.M. peaks, respectively in year 2006. This study shows that there would be no significant increment in CO level for year 2014 although a substantial increase in the number of vehicles is assumed to affect CO levels. It was also found that CO levels would be well below the Malaysian Ambient Air Quality Guideline of 30 ppm (1-h TWA. Comparisons between the measured and simulated CO levels using quantitative data analysis technique and statistical methods indicated that CAL3QHC dispersion model correlated well with measured data.

  7. M Stars in the TW Hydra Association: A Chandra Large Program Survey

    Science.gov (United States)

    Punzi, Kristina; Kastner, Joel; Principe, David; Stelzer, Beate; Gorti, Uma; Pascucci, Illaria; Argiroffi, Costanza

    2018-01-01

    We have conducted a Cycle 18 Chandra Large Program survey of very cool members of the $\\sim$ 8 Myr-old TW Hydra Association (TWA) to extend our previous study of the potential connections between M star disks and X-rays (Kastner et al. 2016, AJ, 152, 3) to the extreme low-mass end of the stellar initial mass function. The spectral types of our targets extend down to the M/L borderline. Thus we can further investigate the potential connection between the intense X-ray emission from young, low-mass stars and the lifetimes of their circumstellar planet-forming discs, as well as better constrain the age at which coronal activity declines for stellar masses approaching the H-burning limit of $\\sim$ 0.08 M$_{\\odot}$. We present preliminary results from the Cycle 18 survey, including X-ray detection statistics and measurements of relative X-ray luminosities and coronal (X-ray) temperatures for those TWA stars detected by Chandra. This research is supported by SAO/CXC grant GO7-18002A and NASA Astrophysics Data Analysis program grants NNX12AH37G and NNX16AG13G to RIT.

  8. Pharmaceuticals, alkylphenols and pesticides in Mediterranean coastal waters: Results from a pilot survey using passive samplers

    Science.gov (United States)

    Munaron, Dominique; Tapie, Nathalie; Budzinski, Hélène; Andral, Bruno; Gonzalez, Jean-Louis

    2012-12-01

    21 pharmaceuticals, 6 alkylphenols and 27 hydrophilic pesticides and biocides were investigated using polar organic contaminant integrative samplers (POCIS) during a large-scale study of contamination of French Mediterranean coastal waters. Marine and transitional water-bodies, defined under the EU Water Framework Directive were monitored. Our results show that the French Mediterranean coastal waters were contaminated with a large range of emerging contaminants, detected at low concentrations during the summer season. Caffeine, carbamazepine, theophilline and terbutaline were detected with a detection frequency higher than 83% in the coastal waters sampled, 4-nonylphenol (4-NP), 4-tert-octylphenol (4-OP) and 4-nonylphenol diethoxylate (NP2EO) were detected in all coastal waters sampled, and diuron, terbuthylazine, atrazine, irgarol and simazine were detected in more than 77% of samples. For pharmaceuticals, highest time-weighted average (TWA) concentrations were measured for caffeine and carbamazepine (32 and 12 ng L-1, respectively). For alkylphenols, highest TWA concentrations were measured for 4-nonylphenol mono-ethoxylate and 4-nonylphenol (41 and 33 ng L-1, respectively), and for herbicides and biocides, they were measured for diuron and irgarol (33 and 2.5 ng L-1, respectively). Except for Diana lagoon, lagoons and semi-enclosed bays were the most contaminated areas for herbicides and pharmaceuticals, whilst, for alkylphenols, levels of contamination were similar in lagoons and coastal waters. This study demonstrates the relevance and utility of POCIS as quantitative tool for measuring low concentrations of emerging contaminants in marine waters.

  9. The release of lindane from contaminated building materials.

    Science.gov (United States)

    Volchek, Konstantin; Thouin, Geneviève; Kuang, Wenxing; Li, Ken; Tezel, F Handan; Brown, Carl E

    2014-10-01

    The release of the organochlorine pesticide lindane (γ-hexachlorocyclohexane) from several types of contaminated building materials was studied to assess inhalation hazard and decontamination requirements in response to accidental and/or intentional spills. The materials included glass, polypropylene carpet, latex-painted drywall, ceramic tiles, vinyl floor tiles, and gypsum ceiling tiles. For each surface concentration, an equilibrium concentration was determined in the vapour phase of the surrounding air. Vapor concentrations depended upon initial surface concentration, temperature, and type of building material. A time-weighted average (TWA) concentration in the air was used to quantify the health risk associated with the inhalation of lindane vapors. Transformation products of lindane, namely α-hexachlorocyclohexane and pentachlorocyclohexene, were detected in the vapour phase at both temperatures and for all of the test materials. Their formation was greater on glass and ceramic tiles, compared to other building materials. An empiric Sips isotherm model was employed to approximate experimental results and to estimate the release of lindane and its transformation products. This helped determine the extent of decontamination required to reduce the surface concentrations of lindane to the levels corresponding to vapor concentrations below TWA.

  10. Current man-made mineral fibers (MMMF) exposures among ontario construction workers.

    Science.gov (United States)

    Verma, Dave K; Sahai, Dru; Kurtz, Lawrence A; Finkelstein, Murray M

    2004-05-01

    Current occupational exposures to man-made mineral fibers (MMMF), including refractory ceramic fibers (RCF), were measured as part of an exposure assessment program for an epidemiological study pertaining to cancer and mortality patterns of Ontario construction workers. The assessments were carried out at commercial and residential sites. A total of 130 MMMF samples (104 personal and 26 area) was collected and included 21 RCF (16 personal and 5 area). The samples were analyzed by the World Health Organization method in which both respirable and nonrespirable airborne fibers are counted. The results show that Ontario construction workers' full-shift exposure to MMMF (excluding RCF) is generally lower than the American Conference of Governmental Industrial Hygienists' (ACGIH) recommended threshold limit value-time-weighted average (TLV-TWA) of 1 fibers/cc and thus should not present any significant hazard. However, approximately 40% of the occupational exposures to RCF are higher than ACGIH's TLV-TWA of 0.2 fibers/cc and present a significant potential hazard. Workers generally wore adequate approved respiratory protection, especially while performing particularly dusty tasks such as blowing, spraying, and cutting, so the actual exposure received by workers was lower than the reported values. Adequate control measures such as ventilation and respiratory protection should always be used when work involves RCF.

  11. Exposure levels of farmers and veterinarians to particulate matter and gases uring operational tasks in pig-fattening houses

    Directory of Open Access Journals (Sweden)

    Nele Van Ransbeeck

    2014-09-01

    Full Text Available The main objective of the study was to assess particulate matter (PM exposure levels for both the farmer and the veterinarian during different operational tasks in pig-fattening houses, and to estimate their exposure levels on a daily working basis (time-weighted average (TWA. The measured PM fractions were: inhalable and respirable PM, PM10, PM2.5 and PM1. The effects of pig age, pen floor type (conventional or low emission surface and cleaning of the pens on the personal PM exposure were also investigated. Indoor concentrations of NH[sub]3[/sub], CH[sub]4[/sub], and CO[sub]2[/sub] were additionally measured during some operational tasks. The results showed that personal exposure levels can become extremely high during some operational tasks performed by the farmer or veterinarian. The highest concentration levels were observed during feed shovelling and blood sampling, the lowest during the weighing of the pigs. For the farmer, the estimated TWA exposure levels of inhalable and respirable PM were 6.0 and 0.29 mg m[sup] -3[/sup] , respectively. These exposure levels for the veterinarian were, respectively, 10.6 and 0.74 mg m[sup] -3[/sup] . The PM concentration levels were mainly determined by the performed operational tasks. There was no significant effect of pig age, pen floor type, nor cleaning of the pens on the personal exposure levels.

  12. DGT Passive Sampling for Quantitative in Situ Measurements of Compounds from Household and Personal Care Products in Waters.

    Science.gov (United States)

    Chen, Wei; Li, Yanying; Chen, Chang-Er; Sweetman, Andrew J; Zhang, Hao; Jones, Kevin C

    2017-11-21

    Widespread use of organic chemicals in household and personal care products (HPCPs) and their discharge into aquatic systems means reliable, robust techniques to monitor environmental concentrations are needed. The passive sampling approach of diffusive gradients in thin-films (DGT) is developed here and demonstrated to provide in situ quantitative and time-weighted average (TWA) measurement of these chemicals in waters. The novel technique is developed for HPCPs, including preservatives, antioxidants and disinfectants, by evaluating the performance of different binding agents. Ultrasonic extraction of binding gels in acetonitrile gave good and consistent recoveries for all test chemicals. Uptake by DGT with HLB (hydrophilic-lipophilic-balanced) as the binding agent was relatively independent of pH (3.5-9.5), ionic strength (0.001-0.1 M) and dissolved organic matter (0-20 mg L -1 ), making it suitable for applications across a wide range of environments. Deployment time and diffusion layer thickness dependence experiments confirmed DGT accumulated chemicals masses are consistent with theoretical predictions. The technique was further tested and applied in the influent and effluent of a wastewater treatment plant. Results were compared with conventional grab-sampling and 24-h-composited samples from autosamplers. DGT provided TWA concentrations over up to 18 days deployment, with minimal effects from biofouling or the diffusive boundary layer. The field application demonstrated advantages of the DGT technique: it gives in situ analyte preconcentration in a simple matrix, with more quantitative measurement of the HPCP analytes.

  13. Evaluation of asbestos exposures during firewood-harvesting simulations in Libby, MT, USA--preliminary data.

    Science.gov (United States)

    Hart, Julie F; Ward, Tony J; Spear, Terry M; Crispen, Kelly; Zolnikov, Tara R

    2007-11-01

    Research was conducted in order to assess potential exposure to asbestos while harvesting firewood from amphibole-contaminated trees near Libby, MT, USA. Three firewood-harvesting simulations took place in the summer and fall of 2006 in the Kootenai Forest inside the US Environmental Protection Agency (EPA) restricted zone surrounding the former W.R. Grace vermiculite mine. Another simulation was conducted near Missoula, MT, USA, which served as the control. The work practices following each simulation were consistent throughout each trial. Personal breathing zone (PBZ) asbestos concentrations were measured by phase contrast microscopy (PCM) and transmission electron microscopy (TEM). Surface wipe samples of personal protective clothing were measured by TEM. The mean (n = 12) PBZ PCM sample time-weighted average (TWA) concentration was 0.29 fibers per milliliter, standard deviation (SD = 0.54). A substantial portion (more than five fibers per sample) of non-asbestos fibers (cellulose) was reported on all PBZ samples (excluding field blanks) when analyzed by TEM. The mean (n = 12) PBZ TEM sample TWA concentration for amphibole fibers 5-microm long was 0.07 fibers per milliliter (SD = 0.08). Substantial amphibole fiber concentrations were revealed on Tyvek clothing wipe samples. The mean concentration (n = 12) was 29 826 fibers per square centimeter (SD = 37 555), with 91% (27 192 fibers per square centimeter) comprised fibers firewood-harvesting activities in asbestos-contaminated areas and that the potential for exposure exists during such activities.

  14. Assessing the active living environment in three rural towns with a high proportion of Native Hawaiians and other Pacific Islanders.

    Science.gov (United States)

    Hafoka, Siosaia F

    2017-01-01

    Background: Existing literature on the built environment and physical activity in rural areas is very limited. Studies have shown that residents in rural areas are less likely to meet physical activity requirements than their counterparts living in urban and suburban areas. They are also less likely to have access to amenities and programs that promote physical activity. This study seeks to fill gaps in the literature by assessing the built environment in three rural towns in Hawai'i that have a high proportion of Native Hawaiians and other Pacific Islanders. Methods: The Rural Active Living Assessment (RALA) tools will be used to assess the built environment. The RALA has three components - Policy and Program Assessment (PPA), Town Wide Assessment (TWA), and Street Segment Assessment (SSA) which will be used to provide a comprehensive assessment of the active living environment. Assessments were completed in September and October 2016. Results: One assessment was completed in each town for the TWA and PPA. The SSA was completed with 60 segments (20 from each town). Conclusion: The RALA tools identified supports in these three rural towns. The assessment also identified barriers and gaps - especially with the town and school polices of each town.

  15. Effects of exposure to ethylene glycol ethers on shipyard painters: II. Male reproduction.

    Science.gov (United States)

    Welch, L S; Schrader, S M; Turner, T W; Cullen, M R

    1988-01-01

    To determine whether 2-ethoxyethanol (2-EE) and 2-methoxyethanol (2-ME) affected the reproductive potential of exposed men, we examined the semen of 73 painters and 40 controls who work in a large shipyard. An industrial hygiene survey was performed to characterize the work environment. The men supplied information on demographic characteristics, medical conditions, personal habits, and reproductive history; underwent a physical examination; and provided a semen sample. Semen samples were analyzed for pH, volume, turbidity, liquidity, viability by stain exclusion and hypo-osmotic stress, sperm density and count per ejaculate, motility using a videotape technique, morphology, and morphometry. Serum was analyzed for testosterone, FSH, and LH. The industrial hygiene survey revealed that the painters were exposed to 2-EE at a time-weighted average (TWA) of 0-80.5 mg/m3 with a mean of 9.9 mg/m3, and to 2-ME at a TWA of 0-17.7 mg/m3 with a mean of 2.6 mg/m3. Painters had an increased prevalence of oligospermia and azoospermia and an increased odds ratio for a lower sperm count per ejaculate, while smoking was controlled. This finding is consistent with prior animal studies and with one human study. Potential biases and confounding of the data are discussed.

  16. Calibration and field evaluation of polar organic chemical integrative sampler (POCIS) for monitoring pharmaceuticals in hospital wastewater

    International Nuclear Information System (INIS)

    Bailly, Emilie; Levi, Yves; Karolak, Sara

    2013-01-01

    The Polar Organic Chemical Integrative Sampler (POCIS) is a new tool for the sampling of organic pollutants in water. We tested this device for the monitoring of pharmaceuticals in hospital wastewater. After calibration, a field application was carried out in a French hospital for six pharmaceutical compounds (Atenolol, Prednisolone, Methylprednisolone, Sulfamethoxazole, Ofloxacin, Ketoprofen). POCIS were calibrated in tap water and wastewater in laboratory conditions close to relevant environmental conditions (temperature, flow velocity). Sampling rates (R s ) were determined and we observed a significant increase with flow velocity and temperature. Whatever the compound, the R s value was lower in wastewater and the linear phase of uptake was shorter. POCIS were deployed in a hospital sewage pipe during four days and the estimated water concentrations were close to those obtained with twenty-four hour composite samples. -- Highlights: ► Calibration of POCIS for the monitoring of pharmaceuticals in hospital wastewater. ► Uptake profile presents a shorter linear phase in wastewater than in tap water. ► Influence of R s values by temperature, flow velocity and bio-fouling. ► Correlation between concentrations estimated from POCIS or measured in TWA samples. ► Deployment period should be no longer than five days. -- After calibration in tap water and hospital wastewater, POCIS were used to monitor pharmaceuticals in hospital sewage and were compared to TWA sampling

  17. Towards a European draft code of practice in creep crack growth testing

    International Nuclear Information System (INIS)

    Nikbin, K.M.

    2003-01-01

    Crack growth and initiation models as well as defect assessment codes need reliable and verifiable material properties data for use in their predictive methodologies. These data consist of uniaxial, multiaxial and crack initiation and growth data under static and cyclic loading at the relevant temperatures. International collaboration for developing standards in this field started in 1987 under the auspices of the VAMAS (Versailles Agreement for MAterials and Standards). Two technical Working Areas TWA11 and TWA19 committees ending 1998 have made substantial progress in unifying and standardising the methods for obtaining the relevant data. This collaboration has resulted in the development of ASTM E1457 creep crack growth testing standard. The European collaborative programme CRETE (see Acknowledgements), which began in 1999, is following up this valuable research in order to develop a European Code of Practice for elevated temperature crack growth which is planned to have a wider field of application. A Round Robin experimental, analytical and verification programme in CRETE will include testing a type 316 LN stainless steel at 550 degC and a Carbon-Manganese steel at 400 degC consisting of seven different geometries. The paper reviews the methods of analysis used for laboratory creep crack growth data and their relevance to long term crack initiation and growth in components. In addition, since design and life assessment and material properties under creep are an integral part of this project a short review of the models available for predicting creep and fatigue crack growth is presented. (author)

  18. A Comparison of "Total Dust" and Inhalable Personal Sampling for Beryllium Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Colleen M. [Tulane Univ., New Orleans, LA (United States). School of Public Health and Tropical Medicine

    2012-05-09

    In 2009, the American Conference of Governmental Industrial Hygienists (ACGIH) reduced the Beryllium (Be) 8-hr Time Weighted Average Threshold Limit Value (TLV-TWA) from 2.0 μg/m3 to 0.05 μg/m3 with an inhalable 'I' designation in accordance with ACGIH's particle size-selective criterion for inhalable mass. Currently, per the Department of Energy (DOE) requirements, the Lawrence Livermore National Laboratory (LLNL) is following the Occupational Health and Safety Administration (OSHA) Permissible Exposure Limit (PEL) of 2.0 μg/m3 as an 8-hr TWA, which is also the 2005 ACGIH TLV-TWA, and an Action Level (AL) of 0.2 μg/m3 and sampling is performed using the 37mm (total dust) sampling method. Since DOE is considering adopting the newer 2009 TLV guidelines, the goal of this study was to determine if the current method of sampling using the 37mm (total dust) sampler would produce results that are comparable to what would be measured using the IOM (inhalable) sampler specific to the application of high energy explosive work at LLNL's remote experimental test facility at Site 300. Side-by-side personal sampling using the two samplers was performed over an approximately two-week period during chamber re-entry and cleanup procedures following detonation of an explosive assembly containing Beryllium (Be). The average ratio of personal sampling results for the IOM (inhalable) vs. 37-mm (total dust) sampler was 1.1:1 with a P-value of 0.62, indicating that there was no statistically significant difference in the performance of the two samplers. Therefore, for the type of activity monitored during this study, the 37-mm sampling cassette would be considered a suitable alternative to the IOM sampler for collecting inhalable particulate matter, which is important given the many practical and economic advantages that it presents. However, similar comparison studies would be necessary for this conclusion to be

  19. Assessment of dust exposure in a steel plant in the eastern coast of peninsular Malaysia.

    Science.gov (United States)

    Nurul, Ainun Hamzah; Shamsul, Bahri Mohd Tamrin; Noor Hassim, Ismail

    2016-11-22

    Steel manufacturing produces dust, fumes, and pollutant gases that may give adverse health effects to the respiratory function of workers. Improper occupational hygiene practice in the workplace will affect both workers wellbeing and productivity. To assess the level of particulate matter [(PM2.5, PM10, and Total Particulate Matter (TPM)], and trace metal dust concentrations in different sections of a steel plant and compare with the occupational exposure values. The work environmental parameters of the particulate matters were evaluated using Indoor Air Quality, while metal dust concentrations were measured using portable personal air sampler. A total of 184 personal samples were randomly collected from workers in three major sections; steel making plant, direct reduced plant, and support group. Trace metal dust concentrations were subjected to wet mineral acid mixture digestion and analysed by atomic absorption spectrophotometer (AAS). The overall average PM2.5 concentration observed was varied according to the section: steel making plant was 0.18 mg/m3, direct reduced iron plant was 0.05 mg/m3, and support plant was 0.05 mg/m3. Average PM 10 concentration in steel making shop (SMS) plant, direct reduced (DR) plant, and support plant were 0.70 mg/m3, 0.84 mg/m3, and 0.58 mg/m3, respectively. The average TWA8 of trace metal dusts (cobalt and chromium) in all the sections exceeded 1 to 3 times the ACGIH prescribed values, OSHA PELs, NIOSH RELs as well as USECHH OSHA, whereas TWA8 concentration of nickel for each section did not exceed the occupational exposure values. The average PM2.5, PM10 and TPM did not exceed the prescribed values, while average trace metal dust concentration TWA8 for cobalt and chromium in all plants exceeded occupational exposure prescribed values. However, the nickel found did not exceed the prescribed values in all the plants except for NIOSH RELs.

  20. Carbon Nanotube and Nanofiber Exposure Assessments: An Analysis of 14 Site Visits

    Science.gov (United States)

    Dahm, Matthew M.; Schubauer-Berigan, Mary K.; Evans, Douglas E.; Birch, M. Eileen; Fernback, Joseph E.; Deddens, James A.

    2015-01-01

    Recent evidence has suggested the potential for wide-ranging health effects that could result from exposure to carbon nanotubes (CNT) and carbon nanofibers (CNF). In response, the National Institute for Occupational Safety and Health (NIOSH) set a recommended exposure limit (REL) for CNT and CNF: 1 µg m−3 as an 8-h time weighted average (TWA) of elemental carbon (EC) for the respirable size fraction. The purpose of this study was to conduct an industrywide exposure assessment among US CNT and CNF manufacturers and users. Fourteen total sites were visited to assess exposures to CNT (13 sites) and CNF (1 site). Personal breathing zone (PBZ) and area samples were collected for both the inhalable and respirable mass concentration of EC, using NIOSH Method 5040. Inhalable PBZ samples were collected at nine sites while at the remaining five sites both respirable and inhalable PBZ samples were collected side-by-side. Transmission electron microscopy (TEM) PBZ and area samples were also collected at the inhalable size fraction and analyzed to quantify and size CNT and CNF agglomerate and fibrous exposures. Respirable EC PBZ concentrations ranged from 0.02 to 2.94 µg m−3 with a geometric mean (GM) of 0.34 µg m−3 and an 8-h TWA of 0.16 µg m−3. PBZ samples at the inhalable size fraction for EC ranged from 0.01 to 79.57 µg m−3 with a GM of 1.21 µg m−3. PBZ samples analyzed by TEM showed concentrations ranging from 0.0001 to 1.613 CNT or CNF-structures per cm3 with a GM of 0.008 and an 8-h TWA concentration of 0.003. The most common CNT structure sizes were found to be larger agglomerates in the 2–5 µm range as well as agglomerates >5 µm. A statistically significant correlation was observed between the inhalable samples for the mass of EC and structure counts by TEM (Spearman ρ = 0.39, P 1 μg m−3. Until more information is known about health effects associated with larger agglomerates, it seems prudent to assess worker exposure to airborne CNT and CNF

  1. Changes in hydro-meteorological conditions over tropical West Africa (1980-2015) and links to global climate

    Science.gov (United States)

    Ndehedehe, Christopher E.; Awange, Joseph L.; Agutu, Nathan O.; Okwuashi, Onuwa

    2018-03-01

    The role of global sea surface temperature (SST) anomalies in modulating rainfall in the African region has been widely studied and is now less debated. However, their impacts and links to terrestrial water storage (TWS) in general, have not been studied. This study presents the pioneer results of canonical correlation analysis (CCA) of TWS derived from both global reanalysis data (1980-2015) and GRACE (Gravity Recovery and Climate Experiment) (2002-2014) with SST fields. The main issues discussed include, (i) oceanic hot spots that impact on TWS over tropical West Africa (TWA) based on CCA, (ii) long term changes in model and global reanalysis data (soil moisture, TWS, and groundwater) and the influence of climate variability on these hydrological indicators, and (iii) the hydrological characteristics of the Equatorial region of Africa (i.e., the Congo basin) based on GRACE-derived TWS, river discharge, and precipitation. Results of the CCA diagnostics show that El-Niño Southern Oscillation related equatorial Pacific SST fluctuations is a major index of climate variability identified in the main portion of the CCA procedure that indicates a significant association with long term TWS reanalysis data over TWA (r = 0.50, ρ < 0.05). Based on Mann-Kendall's statistics, the study found fairly large long term declines (ρ < 0.05) in TWS and soil moisture (1982 - 2015), mostly over the Congo basin, which coincided with warming of the land surface and the surrounding oceans. Meanwhile, some parts of the Sahel show significant wetting (rainfall, soil moisture, groundwater, and TWS) trends during the same period (1982-2015) and aligns with the ongoing narratives of rainfall recovery in the region. Results of singular spectral analysis and regression confirm that multi-annual changes in the Congo River discharge explained a considerable proportion of variability in GRACE-hydrological signal over the Congo basin (r = 0.86 and R2 = 0.70, ρ < 0.05). Finally, leading

  2. An evaluation of retrofit engineering control interventions to reduce perchloroethylene exposures in commercial dry-cleaning shops.

    Science.gov (United States)

    Earnest, G Scott; Ewers, Lynda M; Ruder, Avima M; Petersen, Martin R; Kovein, Ronald J

    2002-02-01

    Real-time monitoring was used to evaluate the ability of engineering control devices retrofitted on two existing dry-cleaning machines to reduce worker exposures to perchloroethylene. In one dry-cleaning shop, a refrigerated condenser was installed on a machine that had a water-cooled condenser to reduce the air temperature, improve vapor recovery, and lower exposures. In a second shop, a carbon adsorber was retrofitted on a machine to adsorb residual perchloroethylene not collected by the existing refrigerated condenser to improve vapor recovery and reduce exposures. Both controls were successful at reducing the perchloroethylene exposures of the dry-cleaning machine operator. Real-time monitoring was performed to evaluate how the engineering controls affected exposures during loading and unloading the dry-cleaning machine, a task generally considered to account for the highest exposures. The real-time monitoring showed that dramatic reductions occurred in exposures during loading and unloading of the dry-cleaning machine due to the engineering controls. Peak operator exposures during loading and unloading were reduced by 60 percent in the shop that had a refrigerated condenser installed on the dry-cleaning machine and 92 percent in the shop that had a carbon adsorber installed. Although loading and unloading exposures were dramatically reduced, drops in full-shift time-weighted average (TWA) exposures were less dramatic. TWA exposures to perchloroethylene, as measured by conventional air sampling, showed smaller reductions in operator exposures of 28 percent or less. Differences between exposure results from real-time and conventional air sampling very likely resulted from other uncontrolled sources of exposure, differences in shop general ventilation before and after the control was installed, relatively small sample sizes, and experimental variability inherent in field research. Although there were some difficulties and complications with installation and

  3. Wolff-Parkinson-White (WPW) syndrome: the detection of delta wave in an electrocardiogram (ECG).

    Science.gov (United States)

    Mahamat, Hassan Adam; Jacquir, Sabir; Khalil, Cliff; Laurent, Gabriel; Binczak, Stephane

    2016-08-01

    The delta wave remains an important indicator to diagnose the WPW syndrome. In this paper, a new method of detection of delta wave in an ECG signal is proposed. Firstly, using the continuous wavelet transform, the P wave, the QRS complex and the T wave are detected, then their durations are computed after determination of the boundary location (onsets and offsets of the P, QRS and T waves). Secondly, the PR duration, the QRS duration and the upstroke of the QRS complex are used to determine the presence or absence of the delta wave. This algorithm has been tested on the Physionel database (ptbdb) in order to evaluate its robustness. It has been applied to clinical signals from patients affected by WPW syndrome. This method can provide assistance to practitioners in order to detect the WPW syndrome.

  4. Disappearance of electrocardiographic abnormalities associated with the arrhythmic pattern of a Barlow disease after surgical mitral valve repair

    Directory of Open Access Journals (Sweden)

    Matteo Augello

    2017-04-01

    Full Text Available We describe the case of a 46-year old female with a Barlow’s disease (MVP characterized by systolic curling of posterior left ventricular (LV wall + significant mitral annular disjunction + complex ventricular arrhythmias + syncope + inverted T waves in inferolateral leads in whom a successful surgical mitral valve rapair determined the disappearance not only of the echocardiographic but also the electrocardiographic abnormalities (in particular the inferolateral T waves inversion on basal electrocardiogram and the complex basal arrhythmic pattern. This case demonstrates that electrocardiographic abnormalities may disappear after the surgical correction of the mechanical stretch imposed on the inferior LV free wall by the prolapsing mitral valve leaflets. Electrocardiographic changes remain an important and easy marker to recognize for the identification of a high-risk subgroup of MVP patients.

  5. ECG-changes following postoperative irradiation of patients with mammary carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Biller, H; Koop, E A; Prignitz, R [Marburg Univ. (Germany, F.R.). Klinik und Poliklinik fuer Strahlentherapie und Roentgendiagnostik

    1979-08-01

    Systematic ECG-analyses and determinations of serum creatin-kinase were performed in 32 patients with mammary carcinoma on the left, prior to and immediately after postoperative radiation therapy. Treatment was done with a gammatron; during this, the average load to the anterior cardiac wall amounted to 3600 rd. Eleven cases exhibited coronary-negative T-waves in at least two chest leads after treatment, seven other cases had flat negative or isoelectric T-waves. Two patients additionally revealed prolongation of the relative QT-period by more than 115%. These changes are interpreted as a sign of radiation-induced myopericarditis. Pericardial effusions did not appear during the follow-up period, furthermore no modifications of creatin-kinase activity. Clinical injury to the patients developed in no case.

  6. Left and Right Ventricle Leads Switch as a Solution for TWave Oversensing - How a Good Idea Turned Out Bad.

    Science.gov (United States)

    Alzand, Bsn; Phlips, Tje; Willems, R

    2014-05-01

    A 50-year-old male with a CRT defibrillator received inappropriate ICD shocks due to T-wave oversensing. Decreasing the sensitivity to avoid T wave oversensing was not an option due to a suboptimal R-wave sensing amplitude. We decided to re-plug the LV lead in the RV port and the RV lead in the LV port. This however led to intermittent phrenic nerve stimulation due to mandatory bipolar (tip-ring) or unipolar (tip-can) pacing on the LV-lead from the RV port. Re-intervention was necessary with the implantation of an additional pacing/sensing RV lead. A software programmable choice to switch sensing and tachycardia detection from RV to LV lead could be a valuable feature in future CRT devices.

  7. Ventricular repolarization alterations in women with angina pectoris and suspected coronary microvascular dysfunction

    DEFF Research Database (Denmark)

    Dose, Nynne; Michelsen, Marie Mide; Mygind, Naja Dam

    2018-01-01

    OBJECTIVES: CMD could be the explanation of angina pectoris with no obstructive CAD and may cause ventricular repolarization changes. We compared T-wave morphology and QTc interval in women with angina pectoris with a control group as well as the associations with CMD. METHODS: Women with angina...... echocardiography. RESULTS: Women with angina pectoris had significantly longer QTc intervals (429±20ms) and increased MCS (IQR) (0.73 [0.64-0.80]) compared with the controls (419±20ms) and (0.63 [(0.53-0.73]), respectively (both p... was attenuated after multivariable adjustment (p=0.08). CONCLUSION: This study suggests that women with angina pectoris have alterations in T-wave morphology as well as longer QTc interval compared with a reference population. CMD might be an explanation....

  8. ECG-changes following postoperative irradiation of patients with mammary carcinoma

    International Nuclear Information System (INIS)

    Biller, H.; Koop, E.A.; Prignitz, R.

    1979-01-01

    Systematic ECG-analyses and determinations of serum creatin-kinase were performed in 32 patients with mammary carcinoma on the left, prior to and immediately after postoperative radiation therapy. Treatment was done with a gammatron; during this, the average load to the anterior cardiac wall amounted to 3600 rd. Eleven cases exhibited coronary-negative T-waves in at least two chest leads after treatment, seven other cases had flat negative or isoelectric T-waves. Two patients additionally revealed prolongation of the relative QT-period by more than 115%. These changes are interpreted as a sign of radiation-induced myopericarditis. Pericardial effusions did not appear during the follow-up period, furthermore no modifications of creatin-kinase activity. Clinical injury to the patients developed in no case. (orig.) [de

  9. Major rapid weight loss induces changes in cardiac repolarization

    DEFF Research Database (Denmark)

    Vedel-Larsen, Esben; Iepsen, Eva Winning; Lundgren, Julie

    2016-01-01

    INTRODUCTION: Obesity is associated with increased all-cause mortality, but weight loss may not decrease cardiovascular events. In fact, very low calorie diets have been linked to arrhythmias and sudden death. The QT interval is the standard marker for cardiac repolarization, but T-wave morphology...... analysis has been suggested as a more sensitive method to identify changes in cardiac repolarization. We examined the effect of a major and rapid weight loss on T-wave morphology. METHODS AND RESULTS: Twenty-six individuals had electrocardiograms (ECG) taken before and after eight weeks of weight loss......A1c (pweight loss induces changes in cardiac repolarization. Monitoring of MCS during calorie restriction makes it possible to detect repolarization changes with higher discriminative power than the QT-interval during major rapid weight...

  10. Wellen’s syndrome: Challenges in diagnosis

    Directory of Open Access Journals (Sweden)

    Abhishek Agarwal

    2015-07-01

    Full Text Available Wellen’s syndrome is a pre-infarction stage of coronary artery disease characterised by predefined clinical and electrocardiographic (ECG criteria of a subgroup of patients with myocardial ischaemia. Early recognition and appropriate intervention of this syndrome carry significant diagnostic and prognostic value. We report this unusual syndrome in an elderly man who presented with recurrent angina and characteristic ECG changes as T-waves inversion in the precordial leads, especially in V2–V6 during pain-free periods and ECG obtained during episodes of pain demonstrating upright T-waves with possible elevated ST segments from V1–V4. Cardiac enzymes were positive and coronary angiography revealed critical stenosis in the proximal left anterior descending artery. It is important to timely identify this condition and intervene appropriately as these patients may develop extensive myocardial infarction that carries a significant morbidity and mortality

  11. Diurnal modulation and sources of variation affecting ventricular repolarization in Warmblood horses

    DEFF Research Database (Denmark)

    Pedersen, Philip Juul; Moeller, Sine B.; Madsen, Mette Flethøj

    2014-01-01

    Te) are used as repolarization markers. To support the use of these markers in horses, we sought to describe the possible influence of the environment, time of day, day-to-day effects, T wave conformation, age, body weight (BW), and horse-to-horse variation on repolarization measurements. ANIMALS: 12 Warmblood...... affecting these intervals. RESULTS: Differences between individual horses were the largest source of repolarization variability although the environment had a significant effect on repolarization as well. Diurnal variation affected both the RR interval and the repolarization markers. The QT, QTc and Tp......, diurnal variation, the environment, and T wave conformation. These factors must be considered if markers of equine repolarization are used diagnostically....

  12. Electrocardiogram pattern of some exotic breeds of trained dogs: A variation study

    Directory of Open Access Journals (Sweden)

    Joydip Mukherjee

    2015-11-01

    Full Text Available Aim: The present study has been conducted to evaluate the variation in electrocardiogram (ECG parameters among different trained breeds of dogs (viz. Labrador, German Shepherd, and Golden Retriever used for security reasons. Materials and Methods: The ECG was recorded by single channel ECG at a paper speed of 25 mm/s and calibration of 10 mm=1 mV. The recordings were taken from all the standard bipolar limb leads (Lead-I, II, and III and unipolar augmented limb leads (Lead-aVR, aVL, and aVF. Results: Heart rate was found to be highest in Labrador and lowest in German Shepherd. P-wave duration was maximum in Golden Retriever breed and lowest in Labrador. Maximum amplitude of P-wave was found in Labrador followed by German Shepherd and Golden Retriever. There was significantly (p<0.05 higher values of PR interval in German Shepherd compared to other breeds. The variation in QRS duration, ST segment duration, T-wave duration, and T-wave amplitude was found to be non-significant among breeds. Inverted T-waves were most common in Golden Retriever and German Shepherd, whereas positive T-waves were found in Labrador. There was significant (p<0.05 variation in mean electrical axis of QRS complex among different breeds and it ranges from +60° to +80°. Conclusion: The present study provides the reference values for different ECG parameters to monitor the cardiac health status among Labrador, German Shepherd, and Golden Retriever breeds.

  13. Method for Correction of Consequences of Radiation-Induced Heart Disease using Low-Intensity Electromagnetic Emission under Experimental Conditions.

    Science.gov (United States)

    Bavrina, A P; Monich, V A; Malinovskaya, S L; Yakovleva, E I; Bugrova, M L; Lazukin, V F

    2015-05-01

    Effects of successive exposure to ionizing irradiation and low-intensity broadband red light on electrical activity of the heart and myocardium microstructure were studied in rats. Lowintensity red light corrected some ECG parameters, in particular, it normalized QT and QTc intervals and voltage of R and T waves. Changes in ECG parameters were followed by alterations in microstructure of muscle fi laments in the myocardium of treatment group animals comparing to control group.

  14. Coexistence of Single Coronary Artery Anomaly and Aortic Arch Anomaly

    OpenAIRE

    Yilmaz Omur Otlu

    2014-01-01

    A 74-year-old male patient was admitted to our hospital for evaluation of recent onset atypical chest pain. His medical history included hypertension, dislipidemia and smoking. Physical examination was unremarkable. The resting electrocardiogram was demonstrated biphasic T waves on lateral derivations. Transthoracic echocardiography showed normal left and right ventricular dimensions and functions. Coronary angiography was planned for the patient. First, right transradial approach tried; but ...

  15. Immediate and Delayed Drug Therapy Effects on Low Dose Sarin Exposed Mice Myocardial Performance

    Science.gov (United States)

    2011-03-01

    studied using electrocardiography ( EKG ) and histological/immunochemical techniques (staining with hematoxylin/eosin and brain natriuretic peptide, BNP...size and BNP levels than controls (p = 0.001). EKGs showed T-wave anomalies. These results are indicators of cardiac insult. The second treatment...mice include being able to only take short time interval readings and the development of movement artifacts in the recordings. To prevent issues

  16. Recognition of regional hypertrophy in hypertrophic cardiomyopathy using thallium-201 emission-computed tomography: comparison with two-dimensional echocardiography

    International Nuclear Information System (INIS)

    Suzuki, Y.; Kadota, K.; Nohara, R.

    1984-01-01

    The configuration of the hypertrophied myocardium was evaluated by thallium-201 emission-computed tomography and 2-dimensional (2-D) sector scan in 10 patients with obstructive hypertrophic cardiomyopathy (HC), 10 with nonobstructive HC with giant negative T waves and 10 with concentric left ventricular (LV) hypertrophy. Thallium-201 myocardial imaging was reconstructed into multiple 12-mm-thick slices in 3 planes. The thickness ratio of the ventricular septum and the LV posterior wall in the short-axis plane and the ratio of the ventricular septum and the apical wall in the long-axis plane were analyzed. In the patients with obstructive HC the ventricular septal wall thickness index was increased, and the ratio of septal to posterior wall thickness index (1.45 +/- 0.23) was greater than that in the patients with nonobstructive HC with giant negative T waves or in those with concentric LV hypertrophy (1.03 +/- 0.20 and 0.98 +/- 0.11, respectively; p less than 0.01 for each). In the patients with nonobstructive HC with giant negative T waves, increased apical wall thickness with apical cavity obliteration was characteristic, and the ratio of ventricular septal to apical wall thickness index (0.66 +/- 0.14) was less than that in the patients with obstructive HC or in those with concentric LV hypertrophy (1.46 +/- 0.38 and 1.04 +/- 0.09, respectively; p less than 0.001 for each). In contrast, technically satisfactory 2-D sector scanning (83%) demonstrated various configurations of the hypertrophied ventricularseptum, but could not detect apical hypertrophy in 4 of the 10 patients with nonobstructive HC with giant negative T waves whose LV cineangiograms demonstrated apical hypertrophy. Thus, thallium-201 emission-computed tomography is useful in evaluating the characteristics of LV hypertrophy and assists 2-D sector scan, especially in patients with apical hypertrophy in HC

  17. Study of ECG changes and its relation to mortality in cases of cerebrovascular accidents.

    Science.gov (United States)

    Purushothaman, Suja; Salmani, Deepalaxmi; Prarthana, Kaleramma Gopalakrishna; Bandelkar, Srinidhi Muddanna Gundappa; Varghese, Sarah

    2014-07-01

    Its being long recognized about the highly debilitating and destructive nature of cerebrovascular accidents (CVAs). Around the world CVAs has posed as a major factor in medical morbidity and mortality. It has thrown up challenges with regards to their medical management and also towards posttreatment rehabilitation. It is well-known that neurologic disorder contributes variously towards varied electrocardiogram (ECG) changes and stroke is no exception. To study the ECG changes and its relation to mortality in cases of CVA. A total of 100 patients with acute stroke were enrolled in the study. All the 100 patients underwent ECG recording within first 24 h of admission. The patients were divided into ischemic and hemorrhagic group depending on the nature of lesion. Out of 100 cases, 58 were ischemic and 42 were hemorrhagic. The ECG changes were noted in 78 patients. Among the ischemic group, the changes noted in the ECG were: T wave inversion (34.48%), ST segment depression (32.75%), QTc prolongation (29.31%), and presence of U waves (27.58%). In cases of hemorrhagic stroke, it was: T wave inversion (33.33%), arrhythmias (33.33%), U waves (30.95%), and ST segment depression (23.80%). Mortality was higher in patients with ST-T changes in ischemic group (66.66%) and in patients with positive U waves (60%) in hemorrhagic group. In acute stroke patients, changes in ECG were commonly seen. The changes varied from T-wave inversion to ST segment depression in ischemic stroke. In hemorrhagic stroke it consisted of T wave inversion and arrhythmias. Overall mortality was high in cases of hemorrhagic compared to ischemic group.

  18. Fresh gasoline emissions, not paved road dust, alter cardiac repolarization in ApoE-/- mice.

    Science.gov (United States)

    Campen, Matthew J; McDonald, Jacob D; Reed, Matthew D; Seagrave, Jeanclare

    2006-01-01

    Fresh vehicular emissions potentially represent a ubiquitous environmental concern for cardiovascular health. We compared electrocardiographic effects of fresh gasoline engine emissions with resuspended paved road dust in a mouse model of coronary insufficiency. Apolipoprotein E (ApoE)-/- mice on a high fat diet were exposed by whole-body inhalation to either gasoline emissions at 60 microg/m3 particulate matter (PM), an equivalent atmosphere with particles filtered out of the whole exhaust, or paved road dust at 0.5 and 3.5 mg /m3 for 6 h/d for 3 d. Radiotelemetry recordings of electrocardiogram (ECG) were analyzed for changes in T-wave morphology (QT interval, T-wave amplitude, and T-wave Area). Following exposures, lung lavage and blood samples were obtained to assay for markers of pulmonary and systemic inflammation. No exposure induced significant changes in heart rate and only the high concentration of road dust induced signs of pulmonary inflammation. T-wave area exhibited significant deviation from baseline values during exposure to gasoline exhaust particulates, but not to either concentration of road dust or gasoline emissions sans particulates. Gasoline-exposed mice demonstrated elevated plasma endothelin-1, but did not cause systemic inflammation. These data support the hypothesis that freshly-generated engine emissions, as opposed to resuspended paved road dust, may drive cardiac effects that have been observed at road-sides in the environment. The absence of ECG effects for both very high concentrations of road dust PM and equivalent concentrations of the vapor/gas phase of gasoline engine exhaust further indicate the specific risk conferred by fresh vehicular PM.

  19. Advanced electrocardiography can predict mitral regurgitation in cavalier king charles spaniels with myxomatous mitral valve disease

    DEFF Research Database (Denmark)

    Spiljak, Maja; Petric, Alexandra; Olsen, Lisbeth Høier

    2011-01-01

    (HRV), QT variability (QTV), T-wave complexity, wave morphology and 3-D ECG. One-way ANOVA determined 21 ECG parameters, which were significantly different (P .... Clinic for Surgery and Small Animal Medicine, Veterinary Faculty, University of Ljubljana, Slovenia. 3. Department of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Denmark. 4. Quality Control Department, Metallurgical and Chemical Industry Cinkarna Celje, INC...

  20. Effects of Single Dose Energy Drink on QT and P-Wave Dispersion

    OpenAIRE

    Arınç, Hüseyin; Sarli, Bahadir; Baktir, Ahmet Oguz; Yolcu, Mustafa; Ozyildirim, Serhan; Kayardi, Mahmut; Cosgun, Mehmet; Erguzel, Nuri; Gunduz, Huseyin; Uyan, Cihangir

    2013-01-01

    Objective: Aim of this study is to evaluate the cardiac electrophysiological effects of energy drink (Red Bull) on QT and P duration and dispersion on surface electrocardiogram.Methods: Twenty healthy volunteers older than 17 years of age were included the study. Subjects with a cardiac rhythm except sinus rhythm, history of atrial or ventricular arrhythmia, family history of premature sudden cardiac death, palpitations, T-wave abnormalities, QTc interval greater than 440 milliseconds, or tho...

  1. Studying the Effects of Mobile Phone Waves on Electro Cardiogram Parameters of Students in Zahedan University of Medical Sciences

    OpenAIRE

    Komeili, Gholamreza; Nabizadeh Sarabandi, Sima

    2012-01-01

    Background The increasing use of mobile phones in recent years has caused concerns about the effects of electromagnetic waves of mobile phonesonhuman biological processes. Objectives This study was conducted in order to survey the effects of mobile electromagnetic waves on electro cardiogram parameters as heart rate, TP segment, PR interval, Time of QRS and T waves, and voltage of R wave. Patients and Methods In this quasi experimental study, 40 students, of Zahedan medical science University...

  2. Automatic ECG analysis using principal component analysis and wavelet transformation

    OpenAIRE

    Khawaja, Antoun

    2007-01-01

    The main objective of this book is to analyse and detect small changes in ECG waves and complexes that indicate cardiac diseases and disorders. Detecting predisposition to Torsade de Points (TDP) by analysing the beat-to-beat variability in T wave morphology is the main core of this work. The second main topic is detecting small changes in QRS complex and predicting future QRS complexes of patients. Moreover, the last main topic is clustering similar ECG components in different groups.

  3. Phase-space treatment of the driven quantum harmonic oscillator

    Indian Academy of Sciences (India)

    2017-02-22

    Feb 22, 2017 ... i.e., ρ(θ,q ,p |q,p,t) is a measure of the interference effects associated ... an oscillating electric field, when the initial state is cho- sen as a .... The conclusive effect is that. A±(q,p,t) ...... wave functions ±(q,p,t) stem from the time depen- dence of ..... define a two-dimensional cell in phase space, which is centred ...

  4. Wellen’s syndrome: Challenges in diagnosis

    OpenAIRE

    Abhishek Agarwal; Sony Vyas; Ravindra Kumar

    2015-01-01

    Wellen’s syndrome is a pre-infarction stage of coronary artery disease characterised by predefined clinical and electrocardiographic (ECG) criteria of a subgroup of patients with myocardial ischaemia. Early recognition and appropriate intervention of this syndrome carry significant diagnostic and prognostic value. We report this unusual syndrome in an elderly man who presented with recurrent angina and characteristic ECG changes as T-waves inversion in the precordial leads, especi...

  5. Intelligent classification of electrocardiogram (ECG) signal using extended Kalman Filter (EKF) based neuro fuzzy system.

    Science.gov (United States)

    Meau, Yeong Pong; Ibrahim, Fatimah; Narainasamy, Selvanathan A L; Omar, Razali

    2006-05-01

    This study presents the development of a hybrid system consisting of an ensemble of Extended Kalman Filter (EKF) based Multi Layer Perceptron Network (MLPN) and a one-pass learning Fuzzy Inference System using Look-up Table Scheme for the recognition of electrocardiogram (ECG) signals. This system can distinguish various types of abnormal ECG signals such as Ventricular Premature Cycle (VPC), T wave inversion (TINV), ST segment depression (STDP), and Supraventricular Tachycardia (SVT) from normal sinus rhythm (NSR) ECG signal.

  6. The UNO Aviation Monograph Series: Aviation Security: An Annotated Bibliography of Responses to the Gore Commission

    Science.gov (United States)

    Carrico, John S.; Schaaf, Michaela M.

    1998-01-01

    This monograph is a companion to UNOAI Monograph 96-2, "The Image of Airport Security: An Annotated Bibliography," compiled in June 1996. The White House Commission on Aviation Safety and Security, headed by Vice President Al Gore, was formed as a result of the TWA Flight 800 crash in August 1996. The Commission's final report included 31 recommendations addressed toward aviation security. The recommendations were cause for security issues to be revisited in the media and by the aviation industry. These developments necessitated the need for an updated bibliography to review the resulting literature. Many of the articles were written in response to the recommendations made by the Gore Commission. "Aviation Security: An Annotated Bibliography of Responses to the Gore Commission" is the result of this need.

  7. Asbestos fiber release from the brake pads of overhead industrial cranes.

    Science.gov (United States)

    Spencer, J W; Plisko, M J; Balzer, J L

    1999-06-01

    The purpose of this evaluation was to determine the actual contribution of airborne asbestos fibers to the work environment from the operation of overhead cranes and hoists that use asbestos composition brake pads. The evaluation was conducted in a working manufacturing facility. Other potential sources of asbestos were accounted for by visual inspection and background air monitoring. An overhead crane assembly comprised of a trolley and two hoists was employed for this study. The crane was operated for two consecutive eight-hour shifts representative of a heavy-duty cycle. Forty-four personal and area air samples were collected during the assessment. Asbestos fibers were analyzed for by phase contrast (NIOSH 7400), and transmission electron (NIOSH 7402) microscopy methods. Eight-hour time-weighted average (TWA) asbestos fiber concentrations ranged from cranes.

  8. Yields of nuclear fragments in the interactions of carbon nuclei with a beryllium target at a projectile energy of 0.6 GeV per nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Abramov, B. M.; Alexeev, P. N.; Borodin, Yu. A.; Bulychjov, S. A. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation); Gudima, K. K. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Dukhovskoy, I. A.; Krutenkova, A. P., E-mail: anna.krutenkova@itep.ru; Kulikov, V. V.; Martemianov, M. A.; Matsyuk, M. A. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation); Mashnik, S. G. [Los Alamos National Laboratory (United States); Turdakina, E. N.; Khanov, A. I. [National Research Center Kurchatov Institute, Institute for Theoretical and Experimental Physics (Russian Federation)

    2016-09-15

    The yields of long-lived nuclear fragments at an angle of 3.5° that originate fromthe fragmentation of carbon ions with an energy of T{sub 0} = 0.6 GeV per nucleon on a berylliumtarget were measured in the FRAGMexperiment at the ITEP TWA heavy-ion accelerator. The momentum spectra of these fragments cover both the fragmentation-maximum region and the cumulative region. The respective differential cross sections change by about five orders of magnitude. The momentum distributions of fragments in the laboratory frame and their kinetic-energy distributions in the rest frame of the fragmenting nucleus are used to test the predictions of four models of ion–ion interactions: BC, INCL++, LAQGSM03.03, and QMD.

  9. Review of health risks in acrylonitrile industry

    Energy Technology Data Exchange (ETDEWEB)

    Guirguis, S S; Cohen, M B; Rajhans, G S

    1984-05-01

    The Occupational Health Branch of the Ontario Ministry of Labour began a study in 1978 for the evaluation of health risks associated with acrylonitrile (AN) exposure. Detailed hygiene and medical investigations were conducted in fourteen plants for evaluating AN exposure in various industrial processes. For companies were also studied in relation to mixed chemical exposure representing acrylic fibres, nitrile rubber, ABS-resin, and acrylic emulsions production. The possible interaction between AN and other coexisting chemical exposures was reviewed since dimethyl formamide, styrene, and butadiene have similar pharmacokinetics and possible synergistic effects. Exposure in acrylic fibre production may be synergistic and carcinogenic. Results of air monitoring indicated exposure levels to AN below 2 ppm (TWA) in most cases. Exposure to other co-existing chemicals was evaluated. Results of medical tests indicated no significant abnormalities in chest x-rays or liver function tests in currently exposed workers.

  10. Divinity and destiny in the religion of Ruanda-Urundi

    Directory of Open Access Journals (Sweden)

    Olof Pettersson

    1967-02-01

    Full Text Available Ruanda and Urundi belong to the Ruanda cluster of the interlactustrine Bantu in the regions surrounded by a great ring of lakes—Tanganyika, Kivu, Edward Albert, Kioga and Victoria. Pygmoid hunters and gatherers still survive among some tribes of the Ruanda cluster, and in both Ruanda and Urundi, people of "Hamitic" (Nilotic origin live side by side with the original tribes. Most of the societies today reveal a sharp stratification into endogamous castes with a ruling aristocracy of herders called Tutsi, a subject agricultural peasanty called Hutu, and often also a depressed caste of Pygmy hunters, called Twa. Even if the beliefs in Ruanda and in Urundi differ in detail, the general religious system is the same among the both peoples. The influences—good or evil—on the life of mankind, on the social orders etc. come from what can be determined as the ultrahuman or superhuman' part of the world.

  11. A study of the differences in respirator fit factor values between years and masks

    Energy Technology Data Exchange (ETDEWEB)

    Longo, Anastasia [Univ. of Minnesota, Minneapolis, MN (United States)

    1995-08-15

    The work described in this report was carried out at a national laboratory of the Department of Energy, during the time that the author was engaged in a Department of Energy Industrial Hygiene Graduate Fellowship. The national laboratory had a respiratory protection program with approximately 50 employees participating. The program was in place to protect employees from over-exposure to airborne contaminants while engineering and work practice controls were being installed and implemented. It was also in place to protect workers in situations where engineering and work control practices were not feasible, such as during maintenance and repair work, as well as in situations where engineering and work practice controls were not enough to lower the exposure to or below the Permissible Exposure Limit (PEL) as set by the Occupational Safety and Health Association (OSHA) as an eight-hour time weighted average (TWA) or an excursion limit. Respirators were also used for emergencies by the emergency response team.

  12. Corrosion of ammunition dumped in the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Jurczak Wojciech

    2017-03-01

    Full Text Available The article presents the preliminary results of a research aimed at preparation for the extraction of chemical ammunition immersed after the Second World War(WWII in the waters of the Baltic Sea (BS. It has been 70 years since the first steps aiming at elimination of mainly German chemical weapons were taken, while the expected durability (tightness of metal barrels construction or other containers was estimated at 50-60 years. Consequently there is a serious risk of contamination of the Baltic Sea waters, not only with toxic warfare agents but also with the products of their decomposition. The evaluation of barrels’ and containers’ with TWA corrosion processes progress will determine the possibility of these munitions extraction to the surface in order to perform their classic utilization.

  13. A Technique for Designing Variation Resilient Subthreshold Sram Cell

    Directory of Open Access Journals (Sweden)

    Aminul Islam

    2013-04-01

    Full Text Available This paper presents a technique for designing a variability aware subthreshold SRAM cell. The architecture of the proposed cell is similar to the standard read-decoupled 8-transistor (RD8T SRAM cell with the exception that the access FETS are replaced with transmission gates (TGs. In this work, various design metrics are assessed and compared with RD8T SRAM cell. The proposed design offers 2.14× and 1.75× improvement in TRA (read access time and TWA (write access time respectively compared with RD8T. It proves its robustness against process variations by featuring narrower spread in TRA distribution (2.35× and TWA distribution (3.79× compared with RD8T. The proposed bitcell offers 1.16× higher read current (IREAD and 1.64× lower bitline leakage current (ILEAK respectively compared with RD8T. It also shows its robustness by offering 1.34× (1.58× tighter spread in IREAD (ILEAK compared with RD8T. It exhibits 1.42× larger IREAD to ILEAK ratio. It shows 2.2× higher frequency @ 250 mV with read bitline capacitance of 10 fF. Besides, the proposed bitcell achieves same read stability and write-ability as that of RD8T at the cost of 3 extra transistors. The leakage power of the proposed design is close to that of RD8T.   ABSTRAK: Kertas kerja ini membentangkan teknik merekabentuk sel bawah ambang SRAM yang bolehubah. Senibina sel yang dicadangkan adalah sama dengan sel SRAM 8-transistor (RD8T “pisahan-bacaan” piawai kecuali FET akses  digantikan dengan sel pintu transmisi (TGs. Di dalam kajian ini, beberapa metrik rekabentuk dinilai dan dibandingkan dengan sel RD8T SRAM. Rekabentuk yang dicadangkan menawarkan  peningkatan 2.14× dan 1.75×  dalam TRA (masa akses baca dan TWA (masa akses tulis berbanding dengan RD8T. Ia membuktikan kekukuhan variasi proses dengan menampilkan tebaran yang lebih sempit dalam pengagihan TRA (2.35 × dan pengagihan TWA (3.79 × berbanding dengan RD8T. Sel-Bit yang dicadangkan mempunyai arus baca 1.16

  14. Technology assessment for the determination of chemical agent vapors in demilitarization facilities: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Maskarinec, M.P.; Wise, M.B.; Buchanan, M.V.

    1987-01-01

    A survey of analytical methods for the determination of chemical agents GB, VX, and HD was made. HD, or mustard, is bis-2-chloroethyl sulfide, and is classified as a blishtering agent. GB, or Sarin, is isopropyl methyl phosphonofluoridate. VX is O-ethyl-S-(2-diisopropylaminoethyl)methylphosphonothioate. Both GB and VX are nerve agents. Included were methods capable of providing for monitoring requirements at the time weighted average (TWA) and allowable stack concentration (ASC) levels in near real time. A review of the currently used automatic continuous air monitoring system (ACAMS) was made as well as a review of the recently developed atmospheric pressure ionization mass spectrometry (APIMS). This report recommends a strategy for research and development for near term and medium term improvement of the overall monitoring program. 12 refs., 1 tab.

  15. A study of the differences in respirator fit factor values between years and masks

    International Nuclear Information System (INIS)

    Longo, A.

    1995-01-01

    The work described in this report was carried out at a national laboratory of the Department of Energy, during the time that the author was engaged in a Department of Energy Industrial Hygiene Graduate Fellowship. The national laboratory had a respiratory protection program with approximately 50 employees participating. The program was in place to protect employees from over-exposure to airborne contaminants while engineering and work practice controls were being installed and implemented. It was also in place to protect workers in situations where engineering and work control practices were not feasible, such as during maintenance and repair work, as well as in situations where engineering and work practice controls were not enough to lower the exposure to or below the Permissible Exposure Limit (PEL) as set by the Occupational Safety and Health Association (OSHA) as an eight-hour time weighted average (TWA) or an excursion limit. Respirators were also used for emergencies by the emergency response team

  16. Adverse effects in coronary angiography: a comparative study of different temperature contrast medium

    International Nuclear Information System (INIS)

    Zhou Peng; Wang Qiulin; Cai Guocai; Li Lu; Jiang Licheng; Yang Zhen; Huang Xiuping

    2011-01-01

    Objective: To investigate the correlation between different temperature contrast medium and the occurrence of adverse effects, including the chest discomfort, the changes of heart rate, ST segment and T wave, the operating time and the used dosage of contrast medium, in performing coronary angiography. Methods: According to the contrast medium temperature used in coronary angiography, the patients were randomly divided into two groups: room temperature group (n=521) and warm temperature group (n=522). The contrast medium used in warm temperature group was bathed in 37 ℃ water for 60 minutes when the coronary angiography was carried out. The T Wave amplitude changes ≥ 0.01 mv, ST segment depression ≥ 0.05 mv, changes in heart rate ≥ 10 times/min were brought into the positive accounting. The occurrence of adverse effects, such as palpitation, chest distress and pectoralgia, the operative time and the used dosage of contrast medium were recorded. The results were analyzed and compared between the two groups. Results: Statistically significant differences in the changes of heart rate, ST segment deviation, T wave change and operating time existed between the two groups (P<0.05). And the difference in the occurrence of adverse effects between the two groups was also statistically significant (P<0.05). Conclusion: When performing coronary angiography, warming of the contrast medium with water bath is greatly conducive to the prevention of cardiac adverse effects. (authors)

  17. Infarct-like acute myocarditis: relation between electrocardiographic findings and myocardial damage as assessed by cardiac magnetic resonance imaging.

    Science.gov (United States)

    Nucifora, Gaetano; Miani, Daniela; Di Chiara, Antonio; Piccoli, Gianluca; Artico, Jessica; Puppato, Michela; Slavich, Gianaugusto; De Biasio, Marzia; Gasparini, Daniele; Proclemer, Alessandro

    2013-03-01

    Acute myocarditis (AM) may occasionally have an infarct-like presentation. The aim of the present study was to investigate the relation between electrocardiographic (ECG) findings in this group of patients and myocardial damage assessed by cardiac magnetic resonance imaging (MRI) with the late gadolinium enhancement (LGE) technique. Myocardial damage may be associated with ECG changes in infarct-like AM. Forty-one consecutive patients (36 males; mean age, 36 ± 12 years) with diagnosis of AM according to cardiac MRI Lake Louise criteria and infarct-like presentation were included. The relation between site of ST-segment elevation (STE), sum of STE (sumSTE), time to normalization of STE, and development of negative T wave with the extent of LGE (expressed as % of left ventricular mass [%LV LGE]), was evaluated. Most (80%) patients presented with inferolateral STE; mean sumSTE was 5 ± 3 mm. Normalization of STE occurred within 24 hours in 20 (49%) patients. Development of negative T wave occurred in 28 (68%) patients. Cardiac MRI showed LGE in all patients; mean %LV LGE was 9.6 ± 7.2%. Topographic agreement between site of STE and LGE was 68%. At multivariate analysis, sumSTE (β = 0.42, P 24 hours (β = 0.39, P 24 hours, and development of negative T wave) may help to identify patients with larger areas of myocardial damage. © 2012 Wiley Periodicals, Inc.

  18. Radiotherapy-induced Early ECG Changes and Their Comparison with Echocardiography in Patients with Early-stage Breast Cancer.

    Science.gov (United States)

    Tuohinen, Suvi Sirkku; Keski-Pukkila, Konsta; Skyttä, Tanja; Huhtala, Heini; Virtanen, Vesa; Kellokumpu-Lehtinen, Pirkko-Liisa; Raatikainen, Pekka; Nikus, Kjell

    2018-04-01

    Early electrocardiogram (ECG) changes after breast cancer radiotherapy (RT) have been reported, but their characteristics and associated factors are largely unknown. This study aimed to explore early RT-induced ECG changes and to compare them with echocardiography changes. Sixty eligible patients with chemotherapy-naïve left-sided and 20 with right-sided breast cancer were evaluated with echocardiography, blood samples and ECG before and after RT. RT-induced ECG changes in the anterior leads. T-Wave changes were most frequent. T-Wave decline was associated independently with patient age (β=-0.245, p=0.005), mean heart radiation dose (β=1.252, p=0.001) and global systolic strain rate change (β=7.943, p=0.002). T-Wave inversion was associated independently with mean heart radiation dose (β=0.143, pECG changes were prevalent and associated with functional and structural changes in echocardiography. ECG could be used for post-RT cardiac screening. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  19. The application of root mean square electrocardiography (RMS ECG) for the detection of acquired and congenital long QT syndrome.

    Science.gov (United States)

    Lux, Robert L; Sower, Christopher Todd; Allen, Nancy; Etheridge, Susan P; Tristani-Firouzi, Martin; Saarel, Elizabeth V

    2014-01-01

    Precise measurement of the QT interval is often hampered by difficulty determining the end of the low amplitude T wave. Root mean square electrocardiography (RMS ECG) provides a novel alternative measure of ventricular repolarization. Experimental data have shown that the interval between the RMS ECG QRS and T wave peaks (RTPK) closely reflects the mean ventricular action potential duration while the RMS T wave width (TW) tracks the dispersion of repolarization timing. Here, we tested the precision of RMS ECG to assess ventricular repolarization in humans in the setting of drug-induced and congenital Long QT Syndrome (LQTS). RMS ECG signals were derived from high-resolution 24 hour Holter monitor recordings from 68 subjects after receiving placebo and moxifloxacin and from standard 12 lead ECGs obtained in 97 subjects with LQTS and 97 age- and sex-matched controls. RTPK, QTRMS and RMS TW intervals were automatically measured using custom software and compared to traditional QT measures using lead II. All measures of repolarization were prolonged during moxifloxacin administration and in LQTS subjects, but the variance of RMS intervals was significantly smaller than traditional lead II measurements. TW was prolonged during moxifloxacin and in subjects with LQT-2, but not LQT-1 or LQT-3. These data validate the application of RMS ECG for the detection of drug-induced and congenital LQTS. RMS ECG measurements are more precise than the current standard of care lead II measurements.

  20. The Effects of Nicorandil and Nifekalant, Which Were Injected into the Pericardial Space, for Transmural Dispersion of Repolarization in the Pig

    Directory of Open Access Journals (Sweden)

    Hiroyuki Ito, MD

    2007-01-01

    Full Text Available Introduction: Some studies have reported that transmural dispersion of repolarization (TDR is involved in the onset of ventricular arrhythmia. We investigated the effects of nicorandil (NIC and nifekalant (NIF injected into the pericardial space, on TDR and T waves in the pig. Methods and Results: We injected NIC 4 or 8 mg and NIF 50 or 100 mg at intervals into the pericardial space for eleven pigs. The effects of these drugs were investigated on the effective refractory period (ERP between the endocardial and epicardial myocardial cells, as well as on QT time, QT peak-end (QTcpe as an index of TDR, and T waveforms, respectively. QTcpe increased from 91 ± 21 to 116 ± 19 msec, 2.8 min after injection of NIC (p < 0.01, although corrected QT (QTc interval did not changed. But 5.5 min after injection, QTc decreased while QTcpe recovered. T wave amplitude significantly increased, and epicardium ERP decreased. When NIF was injected, TDR decreased from 55 ± 10 msec to 44 ± 8 msec (p < 0.01 although QTc did not change. In a later phase, QTc increased (p < 0.01 and QTcpe recovered. T wave amplitude rapidly decreased and became negative. Conclusion: Injected into the pericardial space, NIC and NIF brought about certain changes in ERP, QT and T waveform. Furthermore, NIC increased TDR while NIF decreased TDR.

  1. Aerosol Emission Monitoring and Assessment of Potential Exposure to Multi-walled Carbon Nanotubes in the Manufacture of Polymer Nanocomposites.

    Science.gov (United States)

    Thompson, Drew; Chen, Sheng-Chieh; Wang, Jing; Pui, David Y H

    2015-11-01

    Recent animal studies have shown that carbon nanotubes (CNTs) may pose a significant health risk to those exposed in the workplace. To further understand this potential risk, effort must be taken to measure the occupational exposure to CNTs. Results from an assessment of potential exposure to multi-walled carbon nanotubes (MWCNTs) conducted at an industrial facility where polymer nanocomposites were manufactured by an extrusion process are presented. Exposure to MWCNTs was quantified by the thermal-optical analysis for elemental carbon (EC) of respirable dust collected by personal sampling. All personal respirable samples collected (n = 8) had estimated 8-h time weighted average (TWA) EC concentrations below the limit of detection for the analysis which was about one-half of the recommended exposure limit for CNTs, 1 µg EC/m(3) as an 8-h TWA respirable mass concentration. Potential exposure sources were identified and characterized by direct-reading instruments and area sampling. Area samples analyzed for EC yielded quantifiable mass concentrations inside an enclosure where unbound MWCNTs were handled and near a pelletizer where nanocomposite was cut, while those analyzed by electron microscopy detected the presence of MWCNTs at six locations throughout the facility. Through size selective area sampling it was identified that the airborne MWCNTs present in the workplace were in the form of large agglomerates. This was confirmed by electron microscopy where most of the MWCNT structures observed were in the form of micrometer-sized ropey agglomerates. However, a small fraction of single, free MWCNTs was also observed. It was found that the high number concentrations of nanoparticles, ~200000 particles/cm(3), present in the manufacturing facility were likely attributable to polymer fumes produced in the extrusion process. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  2. Occupational exposure to ethylene oxide--OSHA. Final rule: supplemental statement of reasons.

    Science.gov (United States)

    1985-01-02

    On June 22, 1984, the Occupational Safety and Health Administration (OSHA) published a final standard for ethylene oxide (EtO) that established a permissible exposure limit of 1 part EtO per million parts of air determined as an 8-hour time--weighted average (TWA) concentration (29 CFR 1910.1047, 49 FR 25734). The standard also includes provisions for methods of exposure control, personal protective equipment, measurement of employee exposure, training, signs, and labels, medical surveillance, regulated areas, emergencies and recordkeeping. The basis for this action was a determination by OSHA, based on human and animal data, that exposure to EtO presents a carcinogenic, mutagenic, genotoxic, reproductive, neurologic, and sensitization hazard to workers. During the rulemaking proceedings that led to the establishment of the 1 ppm TWA, the issue of whether there was a need for a short-term exposure limit (STEL) for workers protection from EtO was raised. OSHA reserved decision on the adoption of a STEL at the conclusion of the rulemaking in order to permit peer review of the available evidence and to review more fully the arguments and pertinent data regarding the STEL issue. Upon receipt of the analyses from most of the peer reviewers, OSHA published a notice to that effect on September 19, 1984 (49 FR 36659) and invited public comment on the pertinent issues addressed in the peer reviews. Based on the entire rulemaking record, including the peer reviews and public comments received since June 22, the Assistant Secretary has determined that adoption of a STEL for EtO is not warranted by the available health evidence, and that a STEL is not reasonably necessary or appropriate for inclusion in the final EtO standard. OSHA has also asked that NIOSH fund certain additional studies related to whether a dose-rate relationship can be established for EtO, and OSHA will review the results of those studies when they become available.

  3. Characterization of naturally occurring airborne diacetyl concentrations associated with the preparation and consumption of unflavored coffee

    Directory of Open Access Journals (Sweden)

    Jennifer S. Pierce

    2015-01-01

    Full Text Available Diacetyl, a suspected cause of respiratory disorders in some food and flavorings manufacturing workers, is also a natural component of roasted coffee. We characterized diacetyl exposures that would plausibly occur in a small coffee shop during the preparation and consumption of unflavored coffee. Personal (long- and short-term and area (long-term samples were collected while a barista ground whole coffee beans, and brewed and poured coffee into cups. Simultaneously, long-term personal samples were collected as two participants, the customers, drank one cup of coffee each per h. Air sampling and analyses were conducted in accordance with OSHA Method 1012. Diacetyl was detected in all long-term samples. The long-term concentrations for the barista and area samples were similar, and ranged from 0.013–0.016 ppm; long-term concentrations for the customers were slightly lower and ranged from 0.010–0.014 ppm. Short-term concentrations ranged from below the limit of detection (<0.0047 ppm–0.016 ppm. Mean estimated 8 h time-weighted average (8 h TWA exposures for the barista ranged from 0.007–0.013 ppm; these values exceed recommended 8 h TWA occupational exposure limits (OELs for diacetyl and are comparable to long-term personal measurements collected in various food and beverage production facilities. The concentrations measured based on area sampling were comparable to those measured in the breathing zone of the barista, thus exceedances of the recommended OELs may also occur for coffee shop workers who do not personally prepare coffee (e.g., cashier, sanitation/maintenance. These findings suggest that the practicality and scientific basis of the recommended OELs for diacetyl merit further consideration.

  4. Civamide cream 0.075% in patients with osteoarthritis of the knee: a 12-week randomized controlled clinical trial with a longterm extension.

    Science.gov (United States)

    Schnitzer, Thomas J; Pelletier, Jean-Pierre; Haselwood, Doug M; Ellison, William T; Ervin, John E; Gordon, Richard D; Lisse, Jeffrey R; Archambault, W Tad; Sampson, Allan R; Fezatte, Heidi B; Phillips, Scott B; Bernstein, Joel E

    2012-03-01

    To evaluate the safety and efficacy of civamide cream 0.075% for the treatment of osteoarthritis (OA) of the knee. We conducted a 12-week, multicenter, randomized, double-blind study with a 52-week open-label extension. Patients with OA of the knee received either civamide cream 0.075% or a lower dose of civamide cream, 0.01%, as the control. The 3 co-primary endpoints in the double-blind study were the time-weighted average (TWA) of change from baseline to Day 84 in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale, the WOMAC physical function subscale, and the Subject Global Evaluation (SGE). In the 52-week open-label extension study, the Osteoarthritis Pain Score and SGE were assessed. A total of 695 patients were randomized to receive civamide cream 0.075% (n = 351) or civamide cream 0.01% (control; n = 344) in the double-blind study. Significance in favor of civamide cream 0.075% was achieved for the TWA for all 3 co-primary efficacy variables: WOMAC pain (p = 0.009), WOMAC physical function (p < 0.001), and SGE (p = 0.008); and at Day 84 for these 3 variables (p = 0.013, p < 0.001, and p = 0.049, respectively). These analyses accounted for significant baseline-by-treatment interactions. In the 52-week open-label extension, efficacy was maintained. Civamide cream 0.075% was well tolerated throughout the studies. These studies demonstrate the efficacy of civamide cream for up to 1 year of continuous use. Civamide cream, with its lack of systemic absorption, does not have the potential for serious systemic toxicity, in contrast to several other OA treatments.

  5. Evaluation of the toxicity data for peracetic acid in deriving occupational exposure limits: a minireview.

    Science.gov (United States)

    Pechacek, Nathan; Osorio, Magdalena; Caudill, Jeff; Peterson, Bridget

    2015-02-17

    Peracetic acid (PAA) is a peroxide-based chemistry that is highly reactive and can produce strong local effects upon direct contact with the eyes, skin and respiratory tract. Given its increasing prominence in industry, attention has focused on health hazards and associated risks for PAA in the workplace. Occupational exposure limits (OEL) are one means to mitigate risks associated with chemical hazards in the workplace. A mini-review of the toxicity data for PAA was conducted in order to determine if the data were sufficient to derive health-based OELs. The available data for PAA frequently come from unpublished studies that lack sufficient study details, suffer from gaps in available information and often follow unconventional testing methodology. Despite these limitations, animal and human data suggest sensory irritation as the most sensitive endpoint associated with inhalation of PAA. Rodent RD50 data (the concentration estimated to cause a 50% depression in respiratory rate) were selected as the critical studies in deriving OELs. Based on these data, a range of 0.36-0.51mg/m(3) (0.1-0.2ppm) was calculated for a time-weighted average (TWA), and 1.2-1.7mg/m(3) (0.4-0.5ppm) as a range for a short-term exposure limit (STEL). These ranges compare favorably to other published OELs for PAA. Considering the applicable health hazards for this chemistry, a joint TWA/STEL OEL approach for PAA is deemed the most appropriate in assessing workplace exposures to PAA, and the selection of specific values within these proposed ranges represents a risk management decision. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. Airborne arsenic and urinary excretion of arsenic metabolites during boiler cleaning operations in a Slovak coal-fired power plant

    Energy Technology Data Exchange (ETDEWEB)

    Yager, J.W.; Hicks, J.B.; Fabianova, N. [EPRI, Palo Alto, CA (United States). Environment Group

    1997-08-01

    Little information is available on the relationship between occupational exposure to inorganic arsenic in coal fly ash and urinary excretion of arsenic metabolites. This study was undertaken in a coal-fired power plant in Slovakia during a routine maintenance outage. Arsenic was measured in the breathing zone of workers during 5 consecutive workdays, and urine samples were obtained for analysis of arsenic metabolites-inorganic arsenic (As), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) prior to the start of each shift. Results from a small number of cascade impacter air samples indicated that approximately 90% of total particle mass and arsenic was present in particle size fractions {ge} 3.5 {mu}m. The 8-hr time-weighted average (TWA) mean arsenic air concentration was 48.3 {mu}g/m{sup 3} (range 0.17-375.2) and the mean sum of urinary arsenic (Sigma As) metabolites was 16.9 {mu}g As/g creatinine (range 2.6-50.8). For an 8-hr TWA of 10 {mu}g/m{sup 3} arsenic from coal fly ash, the predicted mean concentration f the Sigma As urinary metabolites was 13.2 {mu}g As/g creatinine. Comparisons with previously published studies of exposure to arsenic trioxide vapors and dusts in copper smelters suggest that bioavailability of arsenic from airborne coal fly ash (as indicated by urinary excretion) is about one-third that seen in smelters and similar settings. Arsenic compound characteristics, matrix composition, and particle size distribution probably play major roles in determining actual uptake of airborne arsenic.

  7. Task-based exposure assessment of nanoparticles in the workplace

    International Nuclear Information System (INIS)

    Ham, Seunghon; Yoon, Chungsik; Lee, Euiseung; Lee, Kiyoung; Park, Donguk; Chung, Eunkyo; Kim, Pilje; Lee, Byoungcheun

    2012-01-01

    Although task-based sampling is, theoretically, a plausible approach to the assessment of nanoparticle exposure, few studies using this type of sampling have been published. This study characterized and compared task-based nanoparticle exposure profiles for engineered nanoparticle manufacturing workplaces (ENMW) and workplaces that generated welding fumes containing incidental nanoparticles. Two ENMW and two welding workplaces were selected for exposure assessments. Real-time devices were utilized to characterize the concentration profiles and size distributions of airborne nanoparticles. Filter-based sampling was performed to measure time-weighted average (TWA) concentrations, and off-line analysis was performed using an electron microscope. Workplace tasks were recorded by researchers to determine the concentration profiles associated with particular tasks/events. This study demonstrated that exposure profiles differ greatly in terms of concentrations and size distributions according to the task performed. The size distributions recorded during tasks were different from both those recorded during periods with no activity and from the background. The airborne concentration profiles of the nanoparticles varied according to not only the type of workplace but also the concentration metrics. The concentrations measured by surface area and the number concentrations measured by condensation particle counter, particulate matter 1.0, and TWA mass concentrations all showed a similar pattern, whereas the number concentrations measured by scanning mobility particle sizer indicated that the welding fume concentrations at one of the welding workplaces were unexpectedly higher than were those at workplaces that were engineering nanoparticles. This study suggests that a task-based exposure assessment can provide useful information regarding the exposure profiles of nanoparticles and can therefore be used as an exposure assessment tool.

  8. Modulation of the SSTA decadal variation on ENSO events and relationships of SSTA With LOD,SOI, etc

    Science.gov (United States)

    Liao, D. C.; Zhou, Y. H.; Liao, X. H.

    2007-01-01

    Interannual and decadal components of the length of day (LOD), Southern Oscillation Index (SOI) and Sea Surface Temperature anomaly (SSTA) in Nino regions are extracted by band-pass filtering, and used for research of the modulation of the SSTA on the ENSO events. Results show that besides the interannual components, the decadal components in SSTA have strong impacts on monitoring and representing of the ENSO events. When the ENSO events are strong, the modulation of the decadal components of the SSTA tends to prolong the life-time of the events and enlarge the extreme anomalies of the SST, while the ENSO events, which are so weak that they can not be detected by the interannual components of the SSTA, can also be detected with the help of the modulation of the SSTA decadal components. The study further draws attention to the relationships of the SSTA interannual and decadal components with those of LOD, SOI, both of the sea level pressure anomalies (SLPA) and the trade wind anomalies (TWA) in tropic Pacific, and also with those of the axial components of the atmospheric angular momentum (AAM) and oceanic angular momentum (OAM). Results of the squared coherence and coherent phases among them reveal close connections with the SSTA and almost all of the parameters mentioned above on the interannual time scales, while on the decadal time scale significant connections are among the SSTA and SOI, SLPA, TWA, ?3w and ?3w+v as well, and slight weaker connections between the SSTA and LOD, ?3pib and ?3bp

  9. [Nanosilver--Occupational exposure limits].

    Science.gov (United States)

    Świdwińska-Gajewska, Anna Maria; Czerczak, Sławomir

    2015-01-01

    Historically, nanosilver has been known as colloidal silver composed of particles with a size below 100 nm. Silver nanoparticles are used in many technologies, creating a wide range of products. Due to antibacterial properties nanosilver is used, among others, in medical devices (wound dressings), textiles (sport clothes, socks), plastics and building materials (paints). Colloidal silver is considered by many as an ideal agent in the fight against pathogenic microorganisms, unlike antibiotics, without side effects. However, in light of toxicological research, nanosilver is not inert to the body. The inhalation of silver nanoparticles have an adverse effect mainly on the liver and lung of rats. The oxidative stress caused by reactive oxygen species is responsible for the toxicity of nanoparticles, contributing to cytotoxic and genotoxic effects. The activity of the readily oxidized nanosilver surface underlies the molecular mechanism of toxicity. This leads to the release of silver ions, a known harmful agent. Occupational exposure to silver nanoparticles may occur in the process of its manufacture, formulation and also usage during spraying, in particular. In Poland, as well as in other countries of the world, there is no separate hygiene standards applicable to nanomaterials. The present study attempts to estimate the value of MAC-TWA (maximum admissible concentration--the time-weighted average) for silver--a nano-objects fraction, which amounted to 0.01 mg/m3. The authors are of the opinion that the current value of the MAC-TWA for silver metallic--inhalable fraction (0.05 mg/m3) does not provide sufficient protection against the harmful effects of silver in the form of nano-objects. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  10. Nanosilver – Occupational exposure limits

    Directory of Open Access Journals (Sweden)

    Anna Maria Świdwińska-Gajewska

    2015-07-01

    Full Text Available Historically, nanosilver has been known as colloidal silver composed of particles with a size below 100 nm. Silver nanoparticles are used in many technologies, creating a wide range of products. Due to antibacterial properties nanosilver is used, among others, in medical devices (wound dressings, textiles (sport clothes, socks, plastics and building materials (paints. Colloidal silver is considered by many as an ideal agent in the fight against pathogenic microorganisms, unlike antibiotics, without side effects. However, in light of toxicological research, nanosilver is not inert to the body. The inhalation of silver nanoparticles have an adverse effect mainly on the liver and lung of rats. The oxidative stress caused by reactive oxygen species is responsible for the toxicity of nanoparticles, contributing to cytotoxic and genotoxic effects. The activity of the readily oxidized nanosilver surface underlies the molecular mechanism of toxicity. This leads to the release of silver ions, a known harmful agent. Occupational exposure to silver nanoparticles may occur in the process of its manufacture, formulation and also usage during spraying, in particular. In Poland, as well as in other countries of the world, there is no separate hygiene standards applicable to nanomaterials. The present study attempts to estimate the value of MAC-TWA (maximum admissible concentration – the time-weighted average for silver – a nano-objects fraction, which amounted to 0.01 mg/m3. The authors are of the opinion that the current value of the MAC-TWA for silver metallic – inhalable fraction (0.05 mg/m3 does not provide sufficient protection against the harmful effects of silver in the form of nano-objects. Med Pr 2015;66(3:429–442

  11. Exposure of miners to diesel exhaust particulates in underground nonmetal mines.

    Science.gov (United States)

    Cohen, H J; Borak, J; Hall, T; Sirianni, G; Chemerynski, S

    2002-01-01

    A study was initiated to examine worker exposures in seven underground nonmetal mines and to examine the precision of the National Institute for Occupational Safety and Health (NIOSH) 5040 sampling and analytical method for diesel exhaust that has recently been adopted for compliance monitoring by the Mine Safety and Health Administration (MSHA). Approximately 1000 air samples using cyclones were taken on workers and in areas throughout the mines. Results indicated that worker exposures were consistently above the MSHA final limit of 160 micrograms/m3 (time-weighted average; TWA) for total carbon as determined by the NIOSH 5040 method and greater than the proposed American Conference of Governmental Industrial Hygienists TLV limit of 20 micrograms/m3 (TWA) for elemental carbon. A number of difficulties were documented when sampling for diesel exhaust using organic carbon: high and variable blank values from filters, a high variability (+/- 20%) from duplicate punches from the same sampling filter, a consistent positive interference (+26%) when open-faced monitors were sampled side-by-side with cyclones, poor correlation (r 2 = 0.38) to elemental carbon levels, and an interference from limestone that could not be adequately corrected by acid-washing of filters. The sampling and analytical precision (relative standard deviation) was approximately 11% for elemental carbon, 17% for organic carbon, and 11% for total carbon. An hypothesis is presented and supported with data that gaseous organic carbon constituents of diesel exhaust adsorb onto not only the submicron elemental carbon particles found in diesel exhaust, but also mining ore dusts. Such mining dusts are mostly nonrespirable and should not be considered equivalent to submicron diesel particulates in their potential for adverse pulmonary effects. It is recommended that size-selective sampling be employed, rather than open-faced monitoring, when using the NIOSH 5040 method.

  12. Noise exposure levels for musicians during rehearsal and performance times.

    Science.gov (United States)

    McIlvaine, Devon; Stewart, Michael; Anderson, Robert

    2012-03-01

    The purpose of this study was to determine daily noise doses and 8-hour time weighted averages for rock band musicians, crew members, and spectators during a typical rehearsal and performance using both Occupational Safety and Health Administration (OSHA) and National Institute of Occupational Safety and Health (NIOSH) measurement criteria. Personal noise dosimetry was completed on five members of a rock band during one 2-hr rehearsal and one 4-hr performance. Time-weighted averages (TWA) and daily dose values were calculated using both OSHA and NIOSH criteria and compared to industry guidelines for enrollment in hearing conservation programs and the use of hearing protection devices. TWA values ranged from 84.3 to 90.4 dBA (OSHA) and from 90.0 to 96.4 dBA (NIOSH) during the rehearsal. The same values ranged from 91.0 to 99.7 dBA (OSHA) and 94.0 to 102.8 dBA (NIOSH) for the performance. During the rehearsal, daily noise doses ranged from 45.54% to 106.7% (OSHA) and from 317.74% to 1396.07% (NIOSH). During the performance, doses ranged from 114.66% to 382.49% (OSHA) and from 793.31% to 5970.15% (NIOSH). The musicians in this study were exposed to dangerously high levels of noise and should be enrolled in a hearing conservation programs. Hearing protection devices should be worn, especially during performances. The OSHA measurement criteria yielded values significantly more conservative than those produced by NIOSH criteria. Audiologists should counsel musician-patients about the hazards of excessive noise (music) exposure and how to protect their hearing.

  13. Conceptual study of an ICRH traveling-wave antenna system for low-coupling conditions as expected in DEMO

    Science.gov (United States)

    Ragona, R.; Messiaen, A.

    2016-07-01

    For the central heating of a fusion reactor ion cyclotron radio frequency heating (ICRH) is the first choice method as it is able to couple RF power to the ions without density limit. The drawback of this heating method is the problem of excitation of the magneto-sonic wave through the plasma boundary layer from the antenna located along the wall, without exceeding its voltage standoff. The amount of coupling depends on the antenna excitation and the surface admittance at the antenna output due to the plasma profile. The paper deals with the optimization of the antenna excitation by the use of sections of traveling-wave antennas (TWAs) distributed all along the reactor wall between the blanket modules. They are mounted and fed in resonant ring system(s). First, the physics of the coupling of a strap array is studied by simple models and the coupling code ANTITER II. Then, after the study of the basic properties of a TWA section, its feeding problem is solved by hybrids driving them in resonant ring circuit(s). The complete modeling is obtained from the matrices of the TWA sections connected to one of the feeding hybrid(s). The solution is iterated with the coupling code to determine the loading for a reference low-coupling ITER plasma profile. The resulting wave pattern up to the plasma bulk is derived. The proposed system is totally load resilient and allows us to obtain a very selective exciting wave spectrum. A discussion of some practical implementation problems is added.

  14. Biological exposure assessment to tetrachloroethylene for workers in the dry cleaning industry

    Directory of Open Access Journals (Sweden)

    Ashley David L

    2008-04-01

    Full Text Available Abstract Background The purpose of this study was to assess the feasibility of conducting biological tetrachloroethylene (perchloroethylene, PCE exposure assessments of dry cleaning employees in conjunction with evaluation of possible PCE health effects. Methods Eighteen women from four dry cleaning facilities in southwestern Ohio were monitored in a pilot study of workers with PCE exposure. Personal breathing zone samples were collected from each employee on two consecutive work days. Biological monitoring included a single measurement of PCE in blood and multiple measurements of pre- and post-shift PCE in exhaled breath and trichloroacetic acid (TCA in urine. Results Post-shift PCE in exhaled breath gradually increased throughout the work week. Statistically significant correlations were observed among the exposure indices. Decreases in PCE in exhaled breath and TCA in urine were observed after two days without exposure to PCE. A mixed-effects model identified statistically significant associations between PCE in exhaled breath and airborne PCE time weighted average (TWA after adjusting for a random participant effect and fixed effects of time and body mass index. Conclusion Although comprehensive, our sampling strategy was challenging to implement due to fluctuating work schedules and the number (pre- and post-shift on three consecutive days and multiplicity (air, blood, exhaled breath, and urine of samples collected. PCE in blood is the preferred biological index to monitor exposures, but may make recruitment difficult. PCE TWA sampling is an appropriate surrogate, although more field intensive. Repeated measures of exposure and mixed-effects modeling may be required for future studies due to high within-subject variability. Workers should be monitored over a long enough period of time to allow the use of a lag term.

  15. Quantification of benzene, toluene, ethylbenzene and o-xylene in internal combustion engine exhaust with time-weighted average solid phase microextraction and gas chromatography mass spectrometry.

    Science.gov (United States)

    Baimatova, Nassiba; Koziel, Jacek A; Kenessov, Bulat

    2015-05-11

    A new and simple method for benzene, toluene, ethylbenzene and o-xylene (BTEX) quantification in vehicle exhaust was developed based on diffusion-controlled extraction onto a retracted solid-phase microextraction (SPME) fiber coating. The rationale was to develop a method based on existing and proven SPME technology that is feasible for field adaptation in developing countries. Passive sampling with SPME fiber retracted into the needle extracted nearly two orders of magnitude less mass (n) compared with exposed fiber (outside of needle) and sampling was in a time weighted-averaging (TWA) mode. Both the sampling time (t) and fiber retraction depth (Z) were adjusted to quantify a wider range of Cgas. Extraction and quantification is conducted in a non-equilibrium mode. Effects of Cgas, t, Z and T were tested. In addition, contribution of n extracted by metallic surfaces of needle assembly without SPME coating was studied. Effects of sample storage time on n loss was studied. Retracted TWA-SPME extractions followed the theoretical model. Extracted n of BTEX was proportional to Cgas, t, Dg, T and inversely proportional to Z. Method detection limits were 1.8, 2.7, 2.1 and 5.2 mg m(-3) (0.51, 0.83, 0.66 and 1.62 ppm) for BTEX, respectively. The contribution of extraction onto metallic surfaces was reproducible and influenced by Cgas and t and less so by T and by the Z. The new method was applied to measure BTEX in the exhaust gas of a Ford Crown Victoria 1995 and compared with a whole gas and direct injection method. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Surgical Success Rates for Horizontal Concomitant Deviations According to the Type and Degree of Deviation

    Directory of Open Access Journals (Sweden)

    İhsan Çaça

    2004-01-01

    Full Text Available We evaluated the correlation with success rates and deviation type and degree inhorizontal concomitant deviations. 104 horizontal concomitan strabismus cases whowere operated in our clinic between January 1994 – December 2000 were included in thestudy. 56 cases undergone recession-resection procedure in the same eye 19 cases twomuscle recession and one muscle resection, 20 cases two muscle recession, 9 cases onlyone muscle recession. 10 ± prism diopter deviation in postoperative sixth monthexamination was accepted as surgical success.Surgical success rate was 90% and 89.3% in the cases with deviation angle of 15-30and 31-50 prism diopter respectively. Success rate was 78.9% if the angle was more than50 prism diopter. According to strabismus type when surgical success rate examined; inalternan esotropia 88.33%, in alternan exotropia 84.6%, in monocular esotropia 88%and in monocular exotropia 83.3% success was fixed. Statistically significant differencewas not found between strabismus type and surgical success rate. The binocular visiongaining rate was found as 51.8% after the treatment of cases.In strabismus surgery, preoperative deviation angle was found to be an effectivefactor on the success rate.

  17. Sialoadenitis bacteriana crónica recurrente de la infancia. Caracterización clínica

    Directory of Open Access Journals (Sweden)

    Carlos Ávila-Sánchez

    2015-03-01

    Full Text Available La sialoadenitis recurrente es el segundo cuadro inflamatorio más frecuente que afecta a la glándula parótida, precedida por la parotiditis viral. Esta afección tiene un cuadro clínico muy similar a la sialoadenitis, motivo por el cual se debe considerar dentro de los  iagnósticos diferenciales. La sialoadenitis recurrente se caracteriza por episodios periódicos de inflamación y aumento de volumen de la glándula parótida acompañados de fiebre y malestar general que alternan con intervalos de remisión en los que la glándula es clínicamente asintomática. En el Instituto Nacional de Pediatría consideramos al concepto Sialoadenitis bacteriana crónica recurrente de la infancia como la definición más específica y completa para referirse a esta enfermedad. Debido a su recurrencia decidimos escribir este artículo para señalar sus características clínicas.

  18. SEMINARIO INTERNACIONAL “NEUROCIENCIAS Y LA INVESTIGACIÓN DEL SUEÑO” PRODUCTIVIDAD Y DESEMPEÑO EN TODAS LAS ESPECIES ANIMALES ASOCIADA AL SUEÑO VOLUMEN

    Directory of Open Access Journals (Sweden)

    Rojas Manuel

    2009-04-01

    Full Text Available Las neurociencias agrupan un amplio espectro de tópicos de investigación en aéreas básicas y clínicas. El estudio del sistema nervioso ha aportado en las últimas décadas información trascendental que permite a la ciencia entender algunos de los circuitos, mecanismos y funciones neuronales que regulan, modulan e inducen diferentes estados de sueño. En los mamíferos es absolutamente evidente la presencia de ciclos que alternan estados de vigilia y de sueño, tanto así que la mayoría de estas especies consumen alrededor de un tercio de la vida durmiendo. Adicionalmente, los índices de producción, productividad y reproducción, así como en general el desempeño durante la vigilia son estrechamente dependientes de la calidad y la cantidad de sueño de los individuos. En consecuencia, profesionales de las ciencias medicas, biológicas y agropecuarias, encuentran puntos de extremo interés y aplicación a partir del conocimiento generado por las neurociencias en torno al fenómeno biológico del sueño.

  19. Species diversity and qualitative assessment of ground beetles (Coleoptera: Carabidae) in three riparian habitats.

    Science.gov (United States)

    Michels, G J; Carney, V A; Jones, E N; Pollock, D A

    2010-06-01

    In a 3-yr study involving saltcedar-free, saltcedar-infested, and burned habitats in a riparian area at Lake Meredith, TX, the number of carabid species collected, diversity indices, and indicator species varied significantly among habitats. A 3-yr average of 15, 14, and 24 carabid species were collected from the saltcedar-free, saltcedar-infested, and burned habitats, respectively. Values for species richness, Shannon's and Simpson's diversity indices, and evenness index for pooled data collected from 2005 to 2007 were higher in the burned habitat followed by the saltcedar-free habitat and the saltcedar-infested habitat. Within-year parameters across the three habitats generally followed the pooled data results with some variation. Nonmetric multidimensional scaling analyses clearly indicated groups of carabid species preferred specific habitats. Five species in the burned area had indicator species percentage values >50% (Agonum punctiforme, Agonum texanum, Brachinus alternans, Harpalus pensylvanicus, and Poecilus chalcites). In the saltcedar-infested and saltcedar-free habitats, only one species in each habitat had indicator species percentage values that exceeded 50%: Calathus opaculus and Cicindela punctulata punctulata, respectively.

  20. Oligosaccharides in Food and Agriculture

    Science.gov (United States)

    Collins, Michelle E.; Rastall, Robert A.

    Oligosaccharides are an integral part of the daily diet for humans and animals. They are primarily used for their nutritional properties, however they are currently receiving much attention due to their physiological effect on the microflora of the gastrointestinal tract. Galacto-oligosaccharides and the fructan-type oligosaccharides, namely FOS and inulin are well established as beneficial to the host and are classified as prebiotic based on data from clinical studies. These compounds dominate this sector of the market, although there are oligosaccharides emerging which have produced very interesting in vitro results in terms of prebiotic status and human trials are required to strengthen the claim. Such compounds include pectic oligosaccharides, gluco-oligosaccharides, gentio-oligosaccharides, kojio-oligosaccharides, and alternan oligosaccharides. The raw materials for production of these prebiotic compounds are derived from natural sources such as plants but also from by products of the food processing industry. In addition to being prebiotic these compounds can be incorporated into foodstuffs due to the physiochemical properties they possess.

  1. Analysis of blood pressure signal in patients with different ventricular ejection fraction using linear and non-linear methods.

    Science.gov (United States)

    Arcentales, Andres; Rivera, Patricio; Caminal, Pere; Voss, Andreas; Bayes-Genis, Antonio; Giraldo, Beatriz F

    2016-08-01

    Changes in the left ventricle function produce alternans in the hemodynamic and electric behavior of the cardiovascular system. A total of 49 cardiomyopathy patients have been studied based on the blood pressure signal (BP), and were classified according to the left ventricular ejection fraction (LVEF) in low risk (LR: LVEF>35%, 17 patients) and high risk (HR: LVEF≤35, 32 patients) groups. We propose to characterize these patients using a linear and a nonlinear methods, based on the spectral estimation and the recurrence plot, respectively. From BP signal, we extracted each systolic time interval (STI), upward systolic slope (BPsl), and the difference between systolic and diastolic BP, defined as pulse pressure (PP). After, the best subset of parameters were obtained through the sequential feature selection (SFS) method. According to the results, the best classification was obtained using a combination of linear and nonlinear features from STI and PP parameters. For STI, the best combination was obtained considering the frequency peak and the diagonal structures of RP, with an area under the curve (AUC) of 79%. The same results were obtained when comparing PP values. Consequently, the use of combined linear and nonlinear parameters could improve the risk stratification of cardiomyopathy patients.

  2. Electrical remodeling of cardiac myocytes from mice with heart failure due to the overexpression of tumor necrosis factor-alpha.

    Science.gov (United States)

    Petkova-Kirova, Polina S; Gursoy, Erdal; Mehdi, Haider; McTiernan, Charles F; London, Barry; Salama, Guy

    2006-05-01

    Mice that overexpress the inflammatory cytokine tumor necrosis factor-alpha in the heart (TNF mice) develop heart failure characterized by atrial and ventricular dilatation, decreased ejection fraction, atrial and ventricular arrhythmias, and increased mortality (males > females). Abnormalities in Ca2+ handling, prolonged action potential duration (APD), calcium alternans, and reentrant atrial and ventricular arrhythmias were previously observed with the use of optical mapping of perfused hearts from TNF mice. We therefore tested whether altered voltage-gated outward K+ and/or inward Ca2+ currents contribute to the altered action potential characteristics and the increased vulnerability to arrhythmias. Whole cell voltage-clamp recordings of K+ currents from left ventricular myocytes of TNF mice revealed an approximately 50% decrease in the rapidly activating, rapidly inactivating transient outward K+ current Ito and in the rapidly activating, slowly inactivating delayed rectifier current IK,slow1, an approximately 25% decrease in the rapidly activating, slowly inactivating delayed rectifier current IK,slow2, and no significant change in the steady-state current Iss compared with controls. Peak amplitudes and inactivation kinetics of the L-type Ca2+ current ICa,L were not altered. Western blot analyses revealed a reduction in the proteins underlying Kv4.2, Kv4.3, and Kv1.5. Thus decreased K+ channel expression is largely responsible for the prolonged APD in the TNF mice and may, along with abnormalities in Ca2+ handling, contribute to arrhythmias.

  3. Atrioventricular node functional remodeling induced by atrial fibrillation.

    Science.gov (United States)

    Zhang, Youhua; Mazgalev, Todor N

    2012-09-01

    The atrioventricular node (AVN) plays a vital role in determining the ventricular rate during atrial fibrillation (AF). AF results in profound electrophysiological and structural remodeling in the atria as well as the sinus node. However, it is unknown whether AVN undergoes remodeling during AF. To determine whether AVN undergoes functional remodeling during AF. AVN conduction properties were studied in vitro in 9 rabbits with AF and 10 normal controls. A previously validated index of AVN dual-pathway electrophysiology, His-electrogram alternans, was used to monitor fast-pathway or slow-pathway (SP) AVN conduction in these experiments. AVN conduction properties were further studied in vivo in 7 dogs with chronic AF and 8 controls. Compared with the control rabbits, the rabbits with AF had a longer AVN conduction time (83 ± 16 ms vs 68 ± 7 ms; P AVN effective refractory period (141 ± 27 ms vs 100 ± 9 ms; P AVN effective refractory period and a slower ventricular rate during AF compared with the controls. Pronounced AVN functional electrophysiological remodeling occurs after long-term AF, which could lead to a spontaneous slowing of the ventricular rate. Furthermore, the SP dominance during AF underscores the effectiveness of its modification by ablation for ventricular rate control during AF. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  4. Coupled iterated map models of action potential dynamics in a one-dimensional cable of cardiac cells

    International Nuclear Information System (INIS)

    Wang Shihong; Xie Yuanfang; Qu Zhilin

    2008-01-01

    Low-dimensional iterated map models have been widely used to study action potential dynamics in isolated cardiac cells. Coupled iterated map models have also been widely used to investigate action potential propagation dynamics in one-dimensional (1D) coupled cardiac cells, however, these models are usually empirical and not carefully validated. In this study, we first developed two coupled iterated map models which are the standard forms of diffusively coupled maps and overcome the limitations of the previous models. We then determined the coupling strength and space constant by quantitatively comparing the 1D action potential duration profile from the coupled cardiac cell model described by differential equations with that of the coupled iterated map models. To further validate the coupled iterated map models, we compared the stability conditions of the spatially uniform state of the coupled iterated maps and those of the 1D ionic model and showed that the coupled iterated map model could well recapitulate the stability conditions, i.e. the spatially uniform state is stable unless the state is chaotic. Finally, we combined conduction into the developed coupled iterated map model to study the effects of coupling strength on wave stabilities and showed that the diffusive coupling between cardiac cells tends to suppress instabilities during reentry in a 1D ring and the onset of discordant alternans in a periodically paced 1D cable

  5. Association between obesity and ECG variables in children and adolescents: A cross-sectional study.

    Science.gov (United States)

    Sun, Guo-Zhe; Li, Yang; Zhou, Xing-Hu; Guo, Xiao-Fan; Zhang, Xin-Gang; Zheng, Li-Qiang; Li, Yuan; Jiao, Yun-DI; Sun, Ying-Xian

    2013-12-01

    Obesity exhibits a wide variety of electrocardiogram (ECG) abnormalities in adults, which often lead to cardiovascular events. However, there is currently no evidence of an association between obesity and ECG variables in children and adolescents. The present study aimed to explore the associations between obesity and ECG intervals and axes in children and adolescents. A cross-sectional observational study of 5,556 students aged 5-18 years was performed. Anthropometric data, blood pressure and standard 12-lead ECGs were collected for each participant. ECG variables were measured manually based on the temporal alignment of simultaneous 12 leads using a CV200 ECG Work Station. Overweight and obese groups demonstrated significantly longer PR intervals, wider QRS durations and leftward shifts of frontal P-wave, QRS and T-wave axes, while the obese group also demonstrated significantly higher heart rates, compared with normal weight groups within normotensive or hypertensive subjects (Pobesity was also associated with longer PR intervals, wider QRS duration and a leftward shift of frontal ECG axes compared with normal waist circumference (WC) within normotensive or hypertensive subjects (Paffecting the ECG variables. Furthermore, the ECG variables, including PR interval, QRS duration and frontal P-wave, QRS and T-wave axes, were significantly linearly correlated with body mass index, WC and waist-to-height ratio adjusted for age, gender, ethnicity and blood pressure. However, there was no significant association between obesity and the corrected QT interval (P>0.05). The results of the current study indicate that in children and adolescents, general and abdominal obesity is associated with longer PR intervals, wider QRS duration and a leftward shift of frontal P-wave, QRS and T-wave axes, independent of age, gender, ethnicity and blood pressure.

  6. Studying the effects of mobile phone waves on electro cardiogram parameters of students in zahedan university of medical sciences.

    Science.gov (United States)

    Komeili, Gholamreza; Nabizadeh Sarabandi, Sima

    2012-01-01

    The increasing use of mobile phones in recent years has caused concerns about the effects of electromagnetic waves of mobile phonesonhuman biological processes. This study was conducted in order to survey the effects of mobile electromagnetic waves on electro cardiogram parameters as heart rate, TP segment, PR interval, Time of QRS and T waves, and voltage of R wave. In this quasi experimental study, 40 students, of Zahedan medical science University, 20 boys and 20 girls, who had referred to the laboratory of physiology were selected. At first a normal electro cardiogram in lead I was recorded for each of the subjects for 20 seconds. Then a mobile phone was placed near their body and while mobile was ringing and talking two other electrocardiograms were recording for 20 seconds. Electro cardiograms were recorded with power lab device and analyzed by chart 5 software. Finally an ANOVA was employed to analyze the data through the SPSS 17, followed by a Tukey test. There was significant difference between heart rate during talking in comparison with heart rate during ringing and resting in both genders. There was a significant decrease of resting TP segment in comparison with TP segment during ringing and talking in males whereas in females TP segment indicated significant difference in all three conditions. There was a significant increase in T wave time in males during talking in comparison with resting and ringing; however there was no significant difference in that of females in any of the three stated conditions. This study revealed that there is not any significant difference in PR interval, Time of QRS wave and R wave voltage. According to the results of this study, mobile phones can affect the heart rate, TP segment and time of T wave. Therefore, it seems that long term use can affect heart. Based on several reports on the effects of these waves on biological processes, precautionary measures should be taken about using mobile phones.

  7. A study of airborne chrysotile concentrations associated with handling, unpacking, and repacking boxes of automobile clutch discs.

    Science.gov (United States)

    Jiang, George C T; Madl, Amy K; Ingmundson, Kelsey J; Murbach, Dana M; Fehling, Kurt A; Paustenbach, Dennis J; Finley, Brent L

    2008-06-01

    concentrations at bystander locations ranged from 0.002+/-0.001 f/cc and 0.004+/-0.002 f/cc when 1 or 2 boxes of clutches were handled, respectively. Estimated 8-h TWA asbestos exposures for a worker handling 1 or 2 boxes of clutches over a workday ranged from 0.002 to 0.006 f/cc. The 30-min PCM adjusted average airborne asbestos concentration for a worker continuously stacking unopened boxes of clutches was 0.212+/-0.014 f/cc; the 8-h TWA was 0.013 f/cc. Additionally, 30-min PCM adjusted average airborne asbestos concentrations following cleanup and clothing handling were 0.002+/-0.001 f/cc and 0.002+/-0.002 f/cc, respectively, both resulting in estimated 8-h TWA asbestos exposures of 0.0001 f/cc. The results of this study indicate that the handling, unpacking, and repacking of clutches, and the subsequent cleanup and clothes handling by a worker within a short-term period or over the entire workday, result in exposures below the historical and current short-term and 8-h occupational exposure limits for asbestos.

  8. INTERNATIONAL UNION OF OPERATING ENGINEERS NATIONAL HAZMAT PROGRAM - DEWALT RECIPROCATING SAW OENHP NUMBER: 2001-01, VERSION A

    International Nuclear Information System (INIS)

    2002-01-01

    Florida International University's (FIU) Hemispheric Center for Environmental Technology (HCET) evaluated five saws for their effectiveness in cutting specially prepared fiberglass-reinforced plywood crates. These crates were built as surrogates for crates that presently hold radioactively contaminated glove boxes at the Department of Energy's (DOE) Los Alamos facility. The DeWalt reciprocating saw was assessed on August 13, 2001. During the FIU test of efficacy, a team from the Operating Engineers National Hazmat Program (OENHP) evaluated the occupational safety and health issues associated with this technology. The DeWalt reciprocating saw is a hand-held industrial tool used for cutting numerous materials, including wood and various types of metals depending upon the chosen blade. Its design allows for cutting close to floors, corners, and other difficult areas. An adjustable shoe sets the cut at three separate depths. During the demonstration for the dismantling of the fiberglass-reinforced plywood crate, the saw was used for extended continuous cutting, over a period of approximately two hours. The dismantling operation involved vertical and horizontal cuts, saw blade changes, and material handling. During this process, operators experienced vibration to the hand and arm in addition to a temperature rise on the handgrip. The blade of the saw is partially exposed during handling and fully exposed during blade changes. Administrative controls, such as duty time of the operators and the machine, operator training, and personal protective equipment (PPE), such as gloves, should be considered when using the saw in this application. Personal noise sampling indicated that both workers were exposed to noise levels exceeding the Occupational Safety and Health Administration's (OSHA) Action Level of 85 decibels (dBA) with time-weighted averages (TWA's) of 88.3 and 90.6 dBA. Normally, a worker would be placed in a hearing conservation program if his TWA was greater than

  9. EVALUATION OF CARDIOLOGIC FUNCTIONS IN CAPTIVE EURASIAN BROWN BEARS (URSUS ARCTOS ARCTOS) IN TURKEY.

    Science.gov (United States)

    Cihan, Huseyin; Yilmaz, Zeki; Aytug, Nilufer

    2016-03-01

    The aim of this study was to evaluate the cardiac functions in healthy Eurasian brown bears (Ursus arctos arctos) living in a seminatural area during their active season. Twelve clinically healthy brown bears were selected based on their normal physical examination, hematologic, and serum biochemistry results. These bears were divided into two groups based on age; subadult (bears. Notching of QRS complexes and peaked T wave were also observed in both groups. Left ventricular diameter at systole and diastole in adult bears was wider (P bears. Subadult bears had reduced aortic diameter compared to adult bears (P bears.

  10. [Changes in the ECG telemetry of lambs infected with Cysticercus ovis].

    Science.gov (United States)

    Kostov, I; Georgieva, D

    1985-01-01

    Six lambs were experimentally infected with Cysticercus ovis. Some changes were followed up in the ECG by means of the radiotelemetric method. The infection process led to the following more important changes, such as sinus tachicardia and arhythmia, auricular fibrilation, sinoauricular block, atrial dissociation, the incidence of a pathologic Q deflection; lowering of the R deflection amplitude, and inversion of the T wave. It was found that the changes referred to persist for a longer period (in the case of infarction), and could be made use of in dispensary studies.

  11. Coexistence of Wolff-Parkinson-white and Brugada syndrome: mere curiosity?

    Science.gov (United States)

    Kaiser, Elisabeth; Sacilotto, Luciana; Darrieux, Francisco; Sosa, Eduardo

    2014-09-01

    The association between Brugada syndrome (BS) and ventricular preexcitation is a rare condition, with sporadic cases already reported. We report the case of a 29-year-old man, with palpitation unrelated to physical or emotional stress. The electrocardiogram of the first visit revealed a ventricular preexcitation pattern and an end-conduction delay, with negative T wave in V1 and intraventricular conduction disturbance in V2 (atypical for BS). The typical aspect of BS occurred after introduction of propafenone for the prevention of atrioventricular tachycardia. We discuss the recognition of this rare association, the proarrhythmic effects of some drugs, treatment options, and prognosis. © 2014 Wiley Periodicals, Inc.

  12. Association of different electrocardiographic patterns with shock index, right ventricle systolic pressure and diameter, and embolic burden score in pulmonary embolism

    Directory of Open Access Journals (Sweden)

    Krća Bojana

    2016-01-01

    Full Text Available Background/Aim. Some electrocardiographic (ECG patterns are characteristic for pulmonary embolism but exact meaning of the different ECG signs are not well known. The aim of this study was to determine the association between four common ECG signs in pulmonary embolism [complete or incomplete right bundle branch block (RBBB, S-waves in the aVL lead, S1Q3T3 sign and negative T-waves in the precordial leads] with shock index (SI, right ventricle diastolic diameter (RVDD and peak systolic pressure (RVSP and embolic burden score (EBS. Methods. The presence of complete or incomplete RBBB, S waves in aVL lead, S1Q3T3 sign and negative T-waves in the precordial leads were determined at admission ECG in 130 consecutive patients admitted to the intensive care unit of a single tertiary medical center in a 5-year period. Echocardiography examination with measurement of RVDD and RVSP, multidetector computed tomography pulmonary angiography (MDCT-PA with the calculation of EBS and SI was determined during the admission process. Multivariable regression models were calculated with ECG parameters as independent variables and the mentioned ultrasound, MDCT-PA parameters and SI as dependent variables. Results. The presence of S-waves in the aVL was the only independent predictor of RVDD (F = 39.430, p < 0.001; adjusted R2 = 0.231 and systolic peak right ventricle pressure (F = 29.903, p < 0.001; adjusted R2 = 0.185. Negative T-waves in precordial leads were the only independent predictor for EBS (F = 24.177, p < 0.001; R2 = 0.160. Complete or incomplete RBBB was the independent predictor of SI (F = 20.980, p < 0.001; adjusted R2 = 0.134. Conclusion. In patients with pulmonary embolism different ECG patterns at admission correlate with different clinical, ultrasound and MDCT-PA parameters. RBBB is associated with shock, Swave in the aVL is associated with right ventricle pressure and negative T-waves with the thrombus burden in the pulmonary tree.

  13. Rupture of an aneurysm of the coronary sinus of Valsalva: diagnosis by helical CT angiography

    International Nuclear Information System (INIS)

    Azarine, A.; Lions, C.; Beregi, J.P.; Koussa, M.

    2001-01-01

    A 75-year-old man presented with a 5-day history of upper chest discomfort. On auscultation, there was a systolic murmur in the left parasternal area that radiated to the apex. Electrocardiography showed flat T waves in the anterior precordial leads. Chest X ray revealed mediastinal enlargement. Transthoracic echocardiography showed a dilated proximal ascending aorta with moderate aortic regurgitation. A contrast-enhanced helical CT scan, performed to eliminate an aortic dissection, showed a ruptured left coronary sinus of Valsalva aneurysm, confirmed at surgery. This case highlights the fact that helical CT, in patients with suspected aortic dissection, may reveal other pathology that accounts for the clinical presentation. (orig.)

  14. Rupture of an aneurysm of the coronary sinus of Valsalva: diagnosis by helical CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Azarine, A.; Lions, C.; Beregi, J.P. [Dept. of Vascular Surgery, Hopital Cardiologique, CHRU de Lille (France); Koussa, M. [Dept. of Vascular Radiology, Hopital Cardiologique, CHRU de Lille (France)

    2001-08-01

    A 75-year-old man presented with a 5-day history of upper chest discomfort. On auscultation, there was a systolic murmur in the left parasternal area that radiated to the apex. Electrocardiography showed flat T waves in the anterior precordial leads. Chest X ray revealed mediastinal enlargement. Transthoracic echocardiography showed a dilated proximal ascending aorta with moderate aortic regurgitation. A contrast-enhanced helical CT scan, performed to eliminate an aortic dissection, showed a ruptured left coronary sinus of Valsalva aneurysm, confirmed at surgery. This case highlights the fact that helical CT, in patients with suspected aortic dissection, may reveal other pathology that accounts for the clinical presentation. (orig.)

  15. The NO Regular Defibrillation testing In Cardioverter Defibrillator Implantation (NORDIC ICD) trial

    DEFF Research Database (Denmark)

    Bänsch, Dietmar; Bonnemeier, Hendrik; Brandt, Johan

    2015-01-01

    was standardized across all participating centres. After inducing a fast ventricular tachycardia (VT) with a heart rate ≥240 b.p.m. or ventricular fibrillation (VF) with a low-energy T-wave shock, DF was attempted with an initial 15 J shock. If the shock reversed the VT or VF, DF testing was considered successful...... and terminated. If unsuccessful, two effective 24 J shocks were administered. If DF was unsuccessful, the system was reconfigured and another DF testing was performed. An ICD shock energy of 40 J had to be programmed in all patients for treatment of spontaneous VT/VF episodes. The primary endpoint...

  16. The algorithmic performance of J-Tpeak for drug safety clinical trial.

    Science.gov (United States)

    Chien, Simon C; Gregg, Richard E

    The interval from J-point to T-wave peak (JTp) in ECG is a new biomarker able to identify drugs that prolong the QT interval but have different ion channel effects. If JTp is not prolonged, the prolonged QT may be associated with multi ion channel block that may have low torsade de pointes risk. From the automatic ECG measurement perspective, accurate and repeatable measurement of JTp involves different challenges than QT. We evaluated algorithm performance and JTp challenges using the Philips DXL diagnostic 12/16/18-lead algorithm. Measurement of JTp represents a different use model. Standard use of corrected QT interval is clinical risk assessment on patients with cardiac disease or suspicion of heart disease. Drug safety trials involve a very different population - young healthy subjects - who commonly have J-waves, notches and slurs. Drug effects include difficult and unusual morphology such as flat T-waves, gentle notches, and multiple T-wave peaks. The JTp initiative study provided ECGs collected from 22 young subjects (11 males and females) in randomized testing of dofetilide, quinidine, ranolazine, verapamil and placebo. We compare the JTp intervals between DXL algorithm and the FDA published measurements. The lead wise, vector-magnitude (VM), root-mean-square (RMS) and principal-component-analysis (PCA) representative beats were used to measure JTp and QT intervals. We also implemented four different methods for T peak detection for comparison. We found that JTp measurements were closer to the reference for combined leads RMS and PCA than individual leads. Differences in J-point location led to part of the JTp measurement difference because of the high prevalence of J-waves, notches and slurs. Larger differences were noted for drug effect causing multiple distinct T-wave peaks (Tp). The automated algorithm chooses the later peak while the reference was the earlier peak. Choosing among different algorithmic strategies in T peak measurement results in the

  17. A dangerous twist of the ‘T’ wave: A case of Wellens’ Syndrome

    Directory of Open Access Journals (Sweden)

    Kavitha Balasubramanian

    2013-03-01

    Full Text Available Wellens’ syndrome is a condition in which electrocardiographic (ECG changes indicate critical proximal left anterior descending artery narrowing occurring during the chest pain-free period. Due to the severity of the obstruction, if such cases are managed by early invasive revascularisation therapy, a major threat in the form of a massive myocardial infarction or sudden death may be averted. We present the case of a patient with previous chest pain, whose ECG showing subtle ischemic changes was initially overlooked. A repeat ECG taken during the painless period showed a biphasic T wave, suggestive of Wellen’s’ syndrome. This was confirmed by an immediate coronary angiogram.

  18. Electrocardiogram of Clinically Healthy Mithun (Bos frontalis): Variation among Strains

    Science.gov (United States)

    Sanyal, Sagar; Das, Pradip Kumar; Ghosh, Probal Ranjan; Das, Kinsuk; Vupru, Kezha V.; Rajkhowa, Chandan; Mondal, Mohan

    2010-01-01

    A study was conducted to establish the normal electrocardiogram in four different genetic strains of mithun (Bos frontalis). Electrocardiography, cardiac electrical axis, heart rate, rectal temperature and respiration rate were recorded in a total of 32 adult male mithun of four strains (n = 8 each). It was found that the respiration and heart rates were higher (P electrocardiogram of mithun revealed that the amplitude and duration of P wave, QRS complex and T wave were different among four different genetic strains of mithun and the electrical axis of QRS complex for Nagamese and Mizoram mithuns are dissimilar to bovine species. PMID:20886013

  19. Non-invasive electrocardiogram detection of in vivo zebrafish embryos using electric potential sensors

    Science.gov (United States)

    Rendon-Morales, E.; Prance, R. J.; Prance, H.; Aviles-Espinosa, R.

    2015-11-01

    In this letter, we report the continuous detection of the cardiac electrical activity in embryonic zebrafish using a non-invasive approach. We present a portable and cost-effective platform based on the electric potential sensing technology, to monitor in vivo electrocardiogram activity from the zebrafish heart. This proof of principle demonstration shows how electrocardiogram measurements from the embryonic zebrafish may become accessible by using electric field detection. We present preliminary results using the prototype, which enables the acquisition of electrophysiological signals from in vivo 3 and 5 days-post-fertilization zebrafish embryos. The recorded waveforms show electrocardiogram traces including detailed features such as QRS complex, P and T waves.

  20. Hemorragias cerebrales y cambios en el E.C.G.

    Directory of Open Access Journals (Sweden)

    Geobel Marín Sánchez

    1963-07-01

    Full Text Available The case of a woman of 60 years of age with a cerebral hemorrhage and a tracing by an electrocardiograph characterized by inverted abd deep "T" waves, is presented, with a prolonging of the "QT" and in which in the autopsy it was impossible to obtain any evidence of a lesion in the myocardium. The most recent reports on this same subject are being checked and it emphasizes the need of having in mind such abnormality in the course of cerebrovascular accidents, in order to avoid mistaken behaviors.

  1. Mesalazine-induced myopericarditis in a patient with ulcerative colitis

    Directory of Open Access Journals (Sweden)

    Jalal Asadi

    2017-12-01

    Full Text Available A 25-year-old male with a background of ulcerative colitis presented with a two-week history of central chest pain. His ECG on presentation showed global T wave inversion with a peak troponin I of 165 ng/mL. Clinical diagnosis of myopericarditis/myocarditis was made. Echocardiography and cardiac magnetic resonance (MR confirmed the diagnosis. On detailed assessment of his medication history, mesalazine was suspected as an etiological factor, with discontinuation resulting in an improvement in symptoms, inflammatory markers and cardiac enzymes. This is a unique case of mesalazine-induced myopericarditis on a background of inflammatory bowel disease.

  2. Takotsubo cardiomyopathy: a case report.

    Science.gov (United States)

    Johar, Sandeep; Prasad, Heramba; Kozman, Hani

    2007-01-01

    A 57-year-old Caucasian woman presented to the emergency department with chest discomfort after testifying in a child custody battle in court. Electrocardiography (ECG) revealed ST-segment elevation in the lateral leads, and T-wave inversions in the inferior and lateral leads. The creatine kinase, creatine kinase-MB, and troponin I concentrations were elevated on presentation. Despite the ECG changes and elevated cardiac markers, coronary angiography demonstrated normal arteries. Left ventricular angiogram revealed an aneurysm at the apex. Takotsubo cardiomyopathy was diagnosed on the basis of these characteristic findings. The patient was discharged on her third hospital day without any complications from the coronary angiography.

  3. The relation between electrocardiographic ST-T changes and NT-proBNP in patients with acute ischemic stroke

    DEFF Research Database (Denmark)

    Jensen, Jesper K; Korsholm, Lars; Høilund-Carlsen, Poul Flemming

    2007-01-01

    BACKGROUND: ST-segment depression and T-wave inversion (ST-T changes) in the electrocardiogram (ECG) and raised levels of natriuretic peptide have been observed in acute ischemic stroke patients. It is unknown whether any relation between ST-T changes and raised levels of natriuretic peptides...... in patients with an acute ischemic stroke exists. METHODS: Serial measurements of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) and 12-lead ECGs were obtained in 192 consecutive patients with an acute ischemic stroke without ischemic heart disease, atrial fibrillation, heart- or renal failure...

  4. Electrocardiographic Changes Improve Risk Prediction in Asymptomatic Persons Age 65 Years or Above Without Cardiovascular Disease

    DEFF Research Database (Denmark)

    Jørgensen, Peter Godsk; Jensen, Jan S; Marott, Jacob L

    2014-01-01

    endpoint was fatal cardiovascular disease (CVD) event and the secondary was fatal or nonfatal CVD event. In our study, 2,236 fatal CVD and 3,849 fatal or nonfatal CVD events occurred during a median of 11.9 and 9.8 years of follow-up. RESULTS: ECG changes were frequently present (30.6%) and associated......: In all, 6,991 participants from the Copenhagen Heart Study attending an examination at age ≥65 years were included. ECG changes were defined as Q waves, ST-segment depression, T-wave changes, ventricular conduction defects, and left ventricular hypertrophy based on the Minnesota code. The primary...

  5. Recognizing Wellens’ syndrome, a warning sign of critical proximal LAD artery stenosis and impending anterior myocardial infarction

    Directory of Open Access Journals (Sweden)

    Laura Hollar

    2015-10-01

    Full Text Available Wellens’ syndrome, also known as LAD coronary T-wave syndrome or the ‘widow maker’, is a pre-infarction syndrome with non-classical ischemic ECG changes and unremarkable cardiac biomarkers. This syndrome continues to be a ‘can't miss’ for the clinician as delay in urgent angiography and intervention can result in anterior myocardial infarction, left ventricular dysfunction, arrhythmias, and death. We describe a case followed by a discussion of identification criteria and clinical implications.

  6. Cerebrogenic tachyarrhythmia in acute stroke

    Directory of Open Access Journals (Sweden)

    A S Praveen Kumar

    2012-01-01

    Full Text Available The electrocardiac abnormalities following acute stroke are frequent and seen in both ischemic and hemorrhagic stroke. The changes seen in electrocardiogram (ECG consist of repolarization abnormalities such as ST elevation, ST depression, negative T waves, and QT prolongation. Among tachyarrhythmias, atrial fibrillation is the most common and occurrence of focal atrial tachycardia is very rare though any cardiac arrhythmias can follow acute stroke. We report a case of focal atrial tachycardia following acute ischemic stroke in 50-year-old female without structural heart disease, and their mechanisms and clinical implications.

  7. [Analysis of correlation between pulmonary function and expression levels of matrix metalloproteinases-9 and tissue inhibitor of metalloproteinase-1 among toluene diisocyanate exposed workers].

    Science.gov (United States)

    Miao, P P; Meng, T; Jia, Q; Niu, Y; Ye, M; Ji, Y Q; Ju, R; Chen, X L; Shao, H; Zheng, Y X; Dai, Y F

    2016-05-01

    To investigate the effect of occupational toluene diisocyanate(TDI) exposure on matrix metalloproteinases-9 (MMP-9) and tissue inhibitor of metalloproteinase-1(TIMP-1), and analysis of the correlation of MMP-9,TIMP-1,MMP-9/TIMP-1 and lung function. In October 2014, based on cluster sampling, we conducted a cross-sectional study in a TDI production factory located in China's western region. 61 exposed workers were recruited from workers engaged in packing, operating and checking. Based on different levels of the external exposure, the packers were classified as high exposed group, while operators and checkers as low exposed group. 58 factory managers, matching age and agent, were selected as controls, having same work intense and not contacting the TDI or other allergens. The questionnaire surveys were used to obtain the agent, age, work age, smoking and drinking, personal and family allergic history, occupational history, and the recent health conditions. The levels of MMP-9 and TIMP-1 in serum of subjects were determind by ELISA. The time weighted average concentrations (8h-TWA) were used to describe the levels of TDI air exposure in working environment. Spearman correlation assay was used to investigate the correlation of MMP-9, TIMP-1, MMP-9/TIMP-1 and lung function, exposure time. 8-hour TWA means of TDI air levels in exposed group, packers, operators and checkers were 0.39, 0.76, 0.25 mg/m(3), respectively . According to the external exposure concentration, the packers were classified as high exposed group, and the operators and checkers were classified as low exposed group. In controls, low exposed group and high exposed group, the levels of MMP-9, respectively, were (807.21±347.70),(586.91±317.50),(388.94±312.01) ng/ml (χ(2)=16.69, Pcorrelation analysis showed that levels of MMP-9 were positively associated with FEV1.0, and FEV1.0/FVC (r values were 0.27, 0.25, respectively, all Pcorrelated with exposure time(r=-0.26, P=0.040). The positive correlations

  8. Occupational Noise Exposure of Employees at Locally-Owned Restaurants in a College Town.

    Science.gov (United States)

    Green, Deirdre R; Anthony, T Renée

    2015-01-01

    While many restaurant employees work in loud environments, in both dining and food preparation areas, little is known about worker exposures to noise. The risk of hearing loss to millions of food service workers around the country is unknown. This study evaluated full-shift noise exposure to workers at six locally-owned restaurants to examine risk factors associated with noise exposures during the day shift. Participants included cooks, counter attendants, bartenders, and waiters at full-service restaurants with bar service and at limited-service restaurants that provided counter service only. Assessments were made on weekdays and weekends, both during the summer and the fall (with a local university in session) to examine whether the time of week or year affects noise exposures to this population in a college town. In addition, the relationships between noise exposures and the type of restaurant and job classification were assessed. One-hundred eighty full-shift time-weighted average (TWA) exposures were assessed, using both Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH) criteria. No TWA measurements exceeded the 90 dBA OSHA 8 hr permissible exposure limit, although six projected TWAs exceeded the 85 dBA OSHA hearing conservation action limit. Using NIOSH criteria, TWAs ranged from 69-90 dBA with a mean of 80 dBA (SD = 4 dBA). Nearly 8% (14) of the exposures exceeded the NIOSH 8-hr 85 dBA. Full-shift exposures were larger for all workers in full-service restaurants (p restaurant type. The fall semester (p = 0.003) and weekend (p = 0.048) exposures were louder than summer and weekdays. Multiple linear regression analysis suggested that the combination of restaurant type, job classification, and season had a significant effect on restaurant worker noise exposures (p restaurant type, job classification, time of week, and season significantly affected the noise exposures for day

  9. Women’s Reasons for Leaving the Engineering Field

    Science.gov (United States)

    Fouad, Nadya A.; Chang, Wen-Hsin; Wan, Min; Singh, Romila

    2017-01-01

    Among the different Science, Technology, Engineering, and Math fields, engineering continues to have one of the highest rates of attrition (Hewlett et al., 2008). The turnover rate for women engineers from engineering fields is even higher than for men (Frehill, 2010). Despite increased efforts from researchers, there are still large gaps in our understanding of the reasons that women leave engineering. This study aims to address this gap by examining the reasons why women leave engineering. Specifically, we analyze the reasons for departure given by national sample of 1,464 women engineers who left the profession after having worked in the engineering field. We applied a person-environment fit theoretical lens, in particular, the Theory of Work Adjustment (TWA) (Dawis and Lofquist, 1984) to understand and categorize the reasons for leaving the engineering field. According to the TWA, occupations have different “reinforcer patterns,” reflected in six occupational values, and a mismatch between the reinforcers provided by the work environment and individuals’ needs may trigger departure from the environment. Given the paucity of literature in this area, we posed research questions to explore the reinforcer pattern of values implicated in women’s decisions to leave the engineering field. We used qualitative analyses to understand, categorize, and code the 1,863 statements that offered a glimpse into the myriad reasons that women offered in describing their decisions to leave the engineering profession. Our results revealed the top three sets of reasons underlying women’s decision to leave the jobs and engineering field were related to: first, poor and/or inequitable compensation, poor working conditions, inflexible and demanding work environment that made work-family balance difficult; second, unmet achievement needs that reflected a dissatisfaction with effective utilization of their math and science skills, and third, unmet needs with regard to lack of

  10. Women's Reasons for Leaving the Engineering Field.

    Science.gov (United States)

    Fouad, Nadya A; Chang, Wen-Hsin; Wan, Min; Singh, Romila

    2017-01-01

    Among the different Science, Technology, Engineering, and Math fields, engineering continues to have one of the highest rates of attrition (Hewlett et al., 2008). The turnover rate for women engineers from engineering fields is even higher than for men (Frehill, 2010). Despite increased efforts from researchers, there are still large gaps in our understanding of the reasons that women leave engineering. This study aims to address this gap by examining the reasons why women leave engineering. Specifically, we analyze the reasons for departure given by national sample of 1,464 women engineers who left the profession after having worked in the engineering field. We applied a person-environment fit theoretical lens, in particular, the Theory of Work Adjustment (TWA) (Dawis and Lofquist, 1984) to understand and categorize the reasons for leaving the engineering field. According to the TWA, occupations have different "reinforcer patterns," reflected in six occupational values, and a mismatch between the reinforcers provided by the work environment and individuals' needs may trigger departure from the environment. Given the paucity of literature in this area, we posed research questions to explore the reinforcer pattern of values implicated in women's decisions to leave the engineering field. We used qualitative analyses to understand, categorize, and code the 1,863 statements that offered a glimpse into the myriad reasons that women offered in describing their decisions to leave the engineering profession. Our results revealed the top three sets of reasons underlying women's decision to leave the jobs and engineering field were related to: first, poor and/or inequitable compensation, poor working conditions, inflexible and demanding work environment that made work-family balance difficult; second, unmet achievement needs that reflected a dissatisfaction with effective utilization of their math and science skills, and third, unmet needs with regard to lack of recognition

  11. Respiratory Symptoms in Hospital Cleaning Staff Exposed to a Product Containing Hydrogen Peroxide, Peracetic Acid, and Acetic Acid

    Science.gov (United States)

    Hawley, Brie; Casey, Megan; Virji, Mohammed Abbas; Cummings, Kristin J.; Johnson, Alyson; Cox-Ganser, Jean

    2017-01-01

    Cleaning and disinfecting products consisting of a mixture of hydrogen peroxide (HP), peracetic acid (PAA), and acetic acid (AA) are widely used as sporicidal agents in health care, childcare, agricultural, food service, and food production industries. HP and PAA are strong oxidants and their mixture is a recognized asthmagen. However, few exposure assessment studies to date have measured HP, PAA, and AA in a health care setting. In 2015, we performed a health and exposure assessment at a hospital where a new sporicidal product, consisting of HP, PAA, and AA was introduced 16 months prior. We collected 49 full-shift time-weighted average (TWA) air samples and analyzed samples for HP, AA, and PAA content. Study participants were observed while they performed cleaning duties, and duration and frequency of cleaning product use was recorded. Acute upper airway, eye, and lower airway symptoms were recorded in a post-shift survey (n = 50). A subset of 35 cleaning staff also completed an extended questionnaire that assessed symptoms reported by workers as regularly occurring or as having occurred in the previous 12 months. Air samples for HP (range: 5.5 to 511.4 ppb) and AA (range: 6.7 to 530.3 ppb) were all below established US occupational exposure limits (OEL). To date, no full-shift TWA OEL for PAA has been established in the United States, however an OEL of 0.2 ppm has been suggested by several research groups. Air samples for PAA ranged from 1.1 to 48.0 ppb and were well below the suggested OEL of 0.2 ppm. Hospital cleaning staff using a sporicidal product containing HP, PAA, and AA reported work-shift eye (44%), upper airway (58%), and lower airway (34%) symptoms. Acute nasal and eye irritation were significantly positively associated with increased exposure to the mixture of the two oxidants: HP and PAA, as well as the total mixture (TM) of HP, PAA, and AA. Shortness of breath when hurrying on level ground or walking up a slight hill was significantly associated

  12. ENGLISH FOLK BALLADS COLLECTED BY CECIL JAMES SHARP IN THE SOUTHERN APPALACHIANS: GENESIS, TRANSFORMATION AND UKRAINIAN PARALLELS

    Directory of Open Access Journals (Sweden)

    Oksana Karbashevska

    2015-04-01

    Full Text Available The purpose of this research, presented at the Conference sectional meeting, is to trace peculiarities of transformation of British folk medieval ballads, which were brought to the Southern Appalachians in the east of the USA by British immigrants at the end of the XVIIIth – beginning of the XIXth century and retained by their descendants, through analyzing certain texts on the levels of motifs, dramatis personae, composition, style and artistic means, as well as to outline relevant Ukrainian parallels. The analysis of such ballads, plot types and epic songs was carried out: 1 British № 10: “The Twa Sisters” (21 variants; American “The Two Sisters”(5 variants and Ukrainian plot type I – C-5: “the elder sister drowns the younger one because of envy and jealousy” (8 variants; 2 British № 26: The Three Ravens” (2, “The Twa Corbies” (2; American “The Three Ravens” (1, “The Two Crows”(1 and Ukrainian epic songs with the motif of lonely death of a Cossack warrior on the steppe (4. In our study British traditional ballads are classified according to the grouping worked out by the American scholar Francis Child (305 numbers, Ukrainian folk ballads – the plot-thematic catalogue developed by the Ukrainian folklorist Оleksiy Dey (here 288 plots are divided into 3 spheres, cycles and plot types. The investigation and comparison of the above indicated texts witness such main tendencies: 1 the American counterparts, collected in the Appalachian Mountains, preserve the historic-national memory and cultural heritage of the British immigrant bearers on the level of leading motifs, dramatis personae, composition peculiarities, traditional medieval images, epithets, similes, commonplaces; 2 some motifs, characters, images, artistic means, archaic and dialectal English of the Child ballads are reduced or substituted in the Appalachian texts; 3 realism of American ballad transformations, which overshadows fantasy and

  13. Respiratory Symptoms in Hospital Cleaning Staff Exposed to a Product Containing Hydrogen Peroxide, Peracetic Acid, and Acetic Acid.

    Science.gov (United States)

    Hawley, Brie; Casey, Megan; Virji, Mohammed Abbas; Cummings, Kristin J; Johnson, Alyson; Cox-Ganser, Jean

    2017-12-15

    Cleaning and disinfecting products consisting of a mixture of hydrogen peroxide (HP), peracetic acid (PAA), and acetic acid (AA) are widely used as sporicidal agents in health care, childcare, agricultural, food service, and food production industries. HP and PAA are strong oxidants and their mixture is a recognized asthmagen. However, few exposure assessment studies to date have measured HP, PAA, and AA in a health care setting. In 2015, we performed a health and exposure assessment at a hospital where a new sporicidal product, consisting of HP, PAA, and AA was introduced 16 months prior. We collected 49 full-shift time-weighted average (TWA) air samples and analyzed samples for HP, AA, and PAA content. Study participants were observed while they performed cleaning duties, and duration and frequency of cleaning product use was recorded. Acute upper airway, eye, and lower airway symptoms were recorded in a post-shift survey (n = 50). A subset of 35 cleaning staff also completed an extended questionnaire that assessed symptoms reported by workers as regularly occurring or as having occurred in the previous 12 months. Air samples for HP (range: 5.5 to 511.4 ppb) and AA (range: 6.7 to 530.3 ppb) were all below established US occupational exposure limits (OEL). To date, no full-shift TWA OEL for PAA has been established in the United States, however an OEL of 0.2 ppm has been suggested by several research groups. Air samples for PAA ranged from 1.1 to 48.0 ppb and were well below the suggested OEL of 0.2 ppm. Hospital cleaning staff using a sporicidal product containing HP, PAA, and AA reported work-shift eye (44%), upper airway (58%), and lower airway (34%) symptoms. Acute nasal and eye irritation were significantly positively associated with increased exposure to the mixture of the two oxidants: HP and PAA, as well as the total mixture (TM)of HP, PAA, and AA. Shortness of breath when hurrying on level ground or walking up a slight hill was significantly associated

  14. Stellar Dynamics

    Science.gov (United States)

    Binney, James

    Gröninger was dissatisfied with his approximate treatment of (141) since it gave poor estimates of the fundamental lines in the waterstuff spectrum. We have even less reason to be satisfied with the Lin-Shu-Kalnajs analysis of (140) which, unaided, is unable to give an adequate account of even the high-frequency normal modes; Personne's programme turns out to involve loosely-wound waves for which the LsK-dispersion relation is not really valid. Obviously more powerful techniques need to be developed for the solution of (140). Meanwhile, is the TWA theory of spiral structure worth bothering with? Quantitatively the TWA theory is not a success. Yet it has played an important role in the study of galaxies by introducing a widely employed conceptual framework. Only after effective machinery for the evaluation of normal modes of disks is available will we know for certain whether this role has been beneficial. In any event one must not underestimate the con- and de-structuve influence on progress in science of the conceptual frameworks that simple models introduce. Two examples will illustrate this point: (i) High-energy physicists think always in terms of particles and interactions and yet these are really just elements (propagators and vertices) introduced during the iterative solution of a set of coupled non-linear integro-differential equations. (ii) Isaac Newton spent vastly more time, thought and experimental effort on chemistry than on either physics or mathematics. Yet his incomparable mind, which both before and after his period as a chemist revolutionized mathematics and first demonstrated the possibility of exact science, achieved nothing of lasting value in Chemistry, whose foundations were to be laid by men of much smaller stature in the mid 18thc. Why did he fail so miserably? Because his conceptual framework was pre-Newtonian; brought up in the mystical, pre-Enlightenment mid 17thc. he thought in terms of the ancient alchemical concepts of corruption and

  15. Factors Associated With Non-compliance of Asbestos Occupational Standards in Brake Repair Workers.

    Science.gov (United States)

    Cely-García, María Fernanda; Curriero, Frank C; Giraldo, Margarita; Méndez, Lorena; Breysse, Patrick N; Durán, Mauricio; Torres-Duque, Carlos A; González-García, Mauricio; Pérez, Carolina; Parada, Patricia; Ramos-Bonilla, Juan Pablo

    2016-10-01

    Asbestos and non-asbestos containing brake products are currently used in low- and middle-income countries like Colombia. Because brake products are distributed detached from their supports, they require manipulation before installation, which release fibers and expose workers. Previous studies of our research group have documented exposures in excess of the widely accepted 0.1 f/cm(3) exposure guideline. The aim of this study is to identify factors associated with non-compliance of the 8-h time weighted average (TWA) 0.1 f/cm(3) asbestos occupational limit among brake mechanics (i.e. riveters). Eighteen brake repair shops (BRS) located in Bogotá (Colombia) were sampled during 3 to 6 consecutive days for the entire work-shift. Personal and short-term personal samples were collected following NIOSH methods 7400 and 7402. Longitudinal based logistic regression models were used to determine the association between the odds of exceeding the 8-h TWA 0.1 f/cm(3) asbestos occupational limit and variables such as type of tasks performed by workers, workload (number of products manipulated daily), years of experience as riveters, and shop characteristics. These models can be used to estimate the odds of being currently or historically overexposed when sampling data do not exist. Since the information required to run the models can vary for both retrospective and current asbestos occupational exposure studies, three models were constructed with different information requirements. The first model evaluated the association between the odds of non-compliance with variables related to the workload, the second model evaluated the association between the odds of non-compliance with variables related to the manipulation tasks, and the third model evaluated the association between the odds of non-compliance with variables related with both the type of tasks performed by workers and the workload. Variables associated with the odds of non-compliance included conducting at least one

  16. Carbon Nanotube Integrative Sampler (CNIS) for passive sampling of nanosilver in the aquatic environment.

    Science.gov (United States)

    Shen, Li; Fischer, Jillian; Martin, Jonathan; Hoque, Md Ehsanul; Telgmann, Lena; Hintelmann, Holger; Metcalfe, Chris D; Yargeau, Viviane

    2016-11-01

    Nanomaterials such as nanosilver (AgNP) can be released into the aquatic environment through production, usage, and disposal. Sensitive and cost-effective methods are needed to monitor AgNPs in the environment. This work is hampered by a lack of sensitive methods to detect nanomaterials in environmental matrixes. The present study focused on the development, calibration and application of a passive sampling technique for detecting AgNPs in aquatic matrixes. A Carbon Nanotube Integrative Sampler (CNIS) was developed using multi-walled carbon nanotubes (CNTs) as the sorbent for accumulating AgNPs and other Ag species from water. Sampling rates were determined in the laboratory for different sampler configurations and in different aquatic matrixes. The sampler was field tested at the Experimental Lakes Area, Canada, in lake water dosed with AgNPs. For a configuration of the CNIS consisting of CNTs bound to carbon fiber (i.e. CNT veil) placed in Chemcatcher® housing, the time weighted average (TWA) concentrations of silver estimated from deployments of the sampler in lake mesocosms dosed with AgNPs were similar to the measured concentrations of "colloidal silver" (i.e. <0.22μm in size) in the water column. For a configuration of CNIS consisting of CNTs in loose powder form placed in a custom made housing that were deployed in a whole lake dosed with AgNPs, the estimated TWA concentrations of "CNIS-labile Ag" were similar to the concentrations of total silver measured in the epilimnion of the lake. However, sampling rates for the CNIS in various matrixes are relatively low (i.e. 1-20mL/day), so deployment periods of several weeks are required to detect AgNPs at environmentally relevant concentrations, which can allow biofilms to develop on the sampler and could affect the sampling rates. With further development, this novel sampler may provide a simple and sensitive method for screening for the presence of AgNPs in surface waters. Copyright © 2016 Elsevier B.V. All

  17. Women’s Reasons for Leaving the Engineering Field

    Directory of Open Access Journals (Sweden)

    Nadya A. Fouad

    2017-06-01

    Full Text Available Among the different Science, Technology, Engineering, and Math fields, engineering continues to have one of the highest rates of attrition (Hewlett et al., 2008. The turnover rate for women engineers from engineering fields is even higher than for men (Frehill, 2010. Despite increased efforts from researchers, there are still large gaps in our understanding of the reasons that women leave engineering. This study aims to address this gap by examining the reasons why women leave engineering. Specifically, we analyze the reasons for departure given by national sample of 1,464 women engineers who left the profession after having worked in the engineering field. We applied a person-environment fit theoretical lens, in particular, the Theory of Work Adjustment (TWA (Dawis and Lofquist, 1984 to understand and categorize the reasons for leaving the engineering field. According to the TWA, occupations have different “reinforcer patterns,” reflected in six occupational values, and a mismatch between the reinforcers provided by the work environment and individuals’ needs may trigger departure from the environment. Given the paucity of literature in this area, we posed research questions to explore the reinforcer pattern of values implicated in women’s decisions to leave the engineering field. We used qualitative analyses to understand, categorize, and code the 1,863 statements that offered a glimpse into the myriad reasons that women offered in describing their decisions to leave the engineering profession. Our results revealed the top three sets of reasons underlying women’s decision to leave the jobs and engineering field were related to: first, poor and/or inequitable compensation, poor working conditions, inflexible and demanding work environment that made work-family balance difficult; second, unmet achievement needs that reflected a dissatisfaction with effective utilization of their math and science skills, and third, unmet needs with

  18. Asbestos exposures of mechanics performing clutch service on motor vehicles.

    Science.gov (United States)

    Cohen, Howard J; Van Orden, Drew R

    2008-03-01

    and frequency of this task, the incremental contribution of this task to mechanics' 8-hr time-weighted average (TWA) asbestos exposures was 0.0016 flcc. Using the range of data inputs that were obtained, the authors calculated a range of TWA exposures of 3.75 x 10(-5) flcc to 0.03 flcc. The mean value of 0.0016 flcc is below background levels of asbestos that have been reported in garages during this time and below the current OSHA PEL of 0.1 flcc.

  19. Personal exposure measurements of school-children to fine particulate matter (PM2.5) in winter of 2013, Shanghai, China.

    Science.gov (United States)

    Zhang, Lijun; Guo, Changyi; Jia, Xiaodong; Xu, Huihui; Pan, Meizhu; Xu, Dong; Shen, Xianbiao; Zhang, Jianghua; Tan, Jianguo; Qian, Hailei; Dong, Chunyang; Shi, Yewen; Zhou, Xiaodan; Wu, Chen

    2018-01-01

    The aim of this study was to perform an exposure assessment of PM2.5 (particulate matter less than 2.5μm in aerodynamic diameter) among children and to explore the potential sources of exposure from both indoor and outdoor environments. In terms of real-time exposure measurements of PM2.5, we collected data from 57 children aged 8-12 years (9.64 ± 0.93 years) in two schools in Shanghai, China. Simultaneously, questionnaire surveys and time-activity diaries were used to estimate the environment at home and daily time-activity patterns in order to estimate the exposure dose of PM2.5 in these children. Principle component regression analysis was used to explore the influence of potential sources of PM2.5 exposure. All the median personal exposure and microenvironment PM2.5 concentrations greatly exceeded the daily 24-h PM2.5 Ambient Air Quality Standards of China, the USA, and the World Health Organization (WHO). The median Etotal (the sum of the PM2.5 exposure levels in different microenvironment and fractional time) of all students was 3014.13 (μg.h)/m3. The concentration of time-weighted average (TWA) exposure of all students was 137.01 μg/m3. The median TWA exposure level during the on-campus period (135.81 μg/m3) was significantly higher than the off-campus period (115.50 μg/m3, P = 0.013 < 0.05). Besides ambient air pollution and meteorological conditions, storey height of the classroom and mode of transportation to school were significantly correlated with children's daily PM2.5 exposure. Children in the two selected schools were exposed to high concentrations of PM2.5 in winter of 2013 in Shanghai. Their personal PM2.5 exposure was mainly associated with ambient air conditions, storey height of the classroom, and children's transportation mode to school.

  20. Contextos cerámicos de los siglos V-VII en Cartagena

    Directory of Open Access Journals (Sweden)

    Ramallo Asensio, Sebastián F.

    1996-12-01

    Full Text Available The excavations realized in the Roman theatre of Cartagena have documented a wide stratigraphie sequence with covers levels from IInd century B.C. to today. The material contexts of Vth to VIIth B.C. are specially interesting because they were associated with considerable removals of the town planning. The construction of a comercial site in the second half of the Vth century, markets and stores, built on a big exedra with portico and 15 divisions in line, represents the total use of the theatre, the structures of which became fossilized, in part, in a new shape. A village of Byzantin age was built over both constructions, characterized with quadrangular rooms which alternates with opened public spaces and irregular streets adjusted to the artificial and inclined topography dependent on the precedent constructions.Las excavaciones realizadas en el teatro romano de Cartagena han documentado una amplia secuencia estratigráfica que abarca desde niveles del siglo II a. de C. hasta nuestros días. Especialmente interesantes son los contextos materiales de los siglos V al VII, asociados a profundas remociones de carácter urbanístico. La construcción en la segunda mitad del siglo V de un complejo comercial, mercado/almacén, estructurado sobre una gran exedra porticada y una serie de 15 compartimentos alineados, representa la amortización total del edificio del teatro cuyas estructuras en parte fosiliza el nuevo conjunto. Encima de ambas construcciones se construyó un barrio de época bizantina caracterizado por habitaciones de forma cuadrangular que alternan con espacios comunes abiertos y calles de trazado irregular adaptadas a la topografía artificial y en pendiente impuesta por las construcciones precedentes.

  1. Peregrinaciones parisinas: Rubén Darío

    Directory of Open Access Journals (Sweden)

    Beatriz Colombi

    1996-11-01

    Full Text Available Hacia 1900 se nuclea en París un grupo de corresponsales latinoamericanos conformando una suerte de enclave que reúne a figuras como Rubén Darío, Manuel Ugarte, Amado Nervo o Enrique Gómez Carrillo. Desde sus respectivas columnas estos cronistas construyen imágenes del mundo moderno atravesadas por el conflicto de pertenencia y marginalidad respecto al mismo. Este trabajo analiza las entregas que Rubén Darío escribe para La Nación de Buenos Aires durante la Feria Internacional de Paris de 1900, en relación con su contexto discursivo. En la enunciación de estas crónicas se alternan pasajes donde prima la superficialidad de la crónica elegante parisina con otras secciones argumentativas que dan cuenta de los desplazamientos de este sujeto entre el 'chroniqueur' y el intelectual que interviene -con la autoridad que le otorga su liderazgo estético- en el campo de los sucesos políticos, desmoronando cualquier 'fetichización' del espectáculo. Darío trama en su crónica la línea 'ondulante' de su prosa de artista con la línea 'informativa' de su tarea de diarista, imponiendo una marca 'modern style' a su escritura, que privilegia imágenes donde se fusionan elementos de ámbitos dispares; también se contamina de la retórica del acontecimiento moderno, en una hibridez propia del efecto sumativo de ese vasto mercado. Las crónicas, reunidas luego en Peregrinaciones de 1901, señalan también el pasaje entre el gran mercado cultural y el pequeño mercado estético, en una posición anfibia propia de esta textualidad

  2. Síntesis y Caracterización de Ag2Cu2O3, el primer óxido de cobre y plata

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    Gómez-Romero, P.

    2000-06-01

    Full Text Available Despite the crystal-chemical similarities between copper and silver ions, there is no known silver copper oxide, neither natural nor synthetic. In this work, we present the synthesis at room-temperature of the first silver copper oxide of formula Ag2Cu2O3 (tetragonal, a=5.8857(3Å, c=10.6868(7Å, space group I41/amd, Z=4. It should be noted that the thermal stability of this new oxide is enhanced with respect to Ag2O or even CuO. The structure consists of alternating chains of edge-sharing square planar Cu(II and zigzag chains of linearly coordinated Ag(I ions.A pesar de las similitudes cristaloquímicas entre los iones de cobre y los de plata, no existe ningún óxido mixto de cobre y plata ni natural ni sintético. En este trabajo se presenta la síntesis a bajas temperaturas del primer óxido mixto de cobre y plata, de fórmula Ag2Cu2O3 (tetragonal, a=5.8857(3Å, c=10.6868(7Å, grupo espacial I41/amd, Z=4. Este óxido posee una estabilidad térmica superior a los correspondientes óxidos de cobre y de plata. Contiene cadenas de iones Cu(II cuadrado-planos que alternan con cadenas en zig-zag de Ag(I con coordinación lineal.

  3. A low-dose β1-blocker in combination with milrinone improves intracellular Ca2+ handling in failing cardiomyocytes by inhibition of milrinone-induced diastolic Ca2+ leakage from the sarcoplasmic reticulum.

    Directory of Open Access Journals (Sweden)

    Shigeki Kobayashi

    Full Text Available OBJECTIVES: The purpose of this study was to investigate whether adding a low-dose β1-blocker to milrinone improves cardiac function in failing cardiomyocytes and the underlying cardioprotective mechanism. BACKGROUND: The molecular mechanism underlying how the combination of low-dose β1-blocker and milrinone affects intracellular Ca(2+ handling in heart failure remains unclear. METHODS: We investigated the effect of milrinone plus landiolol on intracellular Ca(2+ transient (CaT, cell shortening (CS, the frequency of diastolic Ca(2+ sparks (CaSF, and sarcoplasmic reticulum Ca(2+ concentration ({Ca(2+}SR in normal and failing canine cardiomyocytes and used immunoblotting to determine the phosphorylation level of ryanodine receptor (RyR2 and phospholamban (PLB. RESULTS: In failing cardiomyocytes, CaSF significantly increased, and peak CaT and CS markedly decreased compared with normal myocytes. Administration of milrinone alone slightly increased peak CaT and CS, while CaSF greatly increased with a slight increase in {Ca(2+}SR. Co-administration of β1-blocker landiolol to failing cardiomyocytes at a dose that does not inhibit cardiomyocyte function significantly decreased CaSF with a further increase in {Ca(2+}SR, and peak CaT and CS improved compared with milrinone alone. Landiolol suppressed the hyperphosphorylation of RyR2 (Ser2808 in failing cardiomyocytes but had no effect on levels of phosphorylated PLB (Ser16 and Thr17. Low-dose landiolol significantly inhibited the alternans of CaT and CS under a fixed pacing rate (0.5 Hz in failing cardiomyocytes. CONCLUSION: A low-dose β1-blocker in combination with milrinone improved cardiac function in failing cardiomyocytes, apparently by inhibiting the phosphorylation of RyR2, not PLB, and subsequent diastolic Ca(2+ leak.

  4. A low-dose β1-blocker in combination with milrinone improves intracellular Ca2+ handling in failing cardiomyocytes by inhibition of milrinone-induced diastolic Ca2+ leakage from the sarcoplasmic reticulum.

    Science.gov (United States)

    Kobayashi, Shigeki; Susa, Takehisa; Ishiguchi, Hironori; Myoren, Takeki; Murakami, Wakako; Kato, Takayoshi; Fukuda, Masakazu; Hino, Akihiro; Suetomi, Takeshi; Ono, Makoto; Uchinoumi, Hitoshi; Tateishi, Hiroki; Mochizuki, Mamoru; Oda, Tetsuro; Okuda, Shinichi; Doi, Masahiro; Yamamoto, Takeshi; Yano, Masafumi

    2015-01-01

    The purpose of this study was to investigate whether adding a low-dose β1-blocker to milrinone improves cardiac function in failing cardiomyocytes and the underlying cardioprotective mechanism. The molecular mechanism underlying how the combination of low-dose β1-blocker and milrinone affects intracellular Ca(2+) handling in heart failure remains unclear. We investigated the effect of milrinone plus landiolol on intracellular Ca(2+) transient (CaT), cell shortening (CS), the frequency of diastolic Ca(2+) sparks (CaSF), and sarcoplasmic reticulum Ca(2+) concentration ({Ca(2+)}SR) in normal and failing canine cardiomyocytes and used immunoblotting to determine the phosphorylation level of ryanodine receptor (RyR2) and phospholamban (PLB). In failing cardiomyocytes, CaSF significantly increased, and peak CaT and CS markedly decreased compared with normal myocytes. Administration of milrinone alone slightly increased peak CaT and CS, while CaSF greatly increased with a slight increase in {Ca(2+)}SR. Co-administration of β1-blocker landiolol to failing cardiomyocytes at a dose that does not inhibit cardiomyocyte function significantly decreased CaSF with a further increase in {Ca(2+)}SR, and peak CaT and CS improved compared with milrinone alone. Landiolol suppressed the hyperphosphorylation of RyR2 (Ser2808) in failing cardiomyocytes but had no effect on levels of phosphorylated PLB (Ser16 and Thr17). Low-dose landiolol significantly inhibited the alternans of CaT and CS under a fixed pacing rate (0.5 Hz) in failing cardiomyocytes. A low-dose β1-blocker in combination with milrinone improved cardiac function in failing cardiomyocytes, apparently by inhibiting the phosphorylation of RyR2, not PLB, and subsequent diastolic Ca(2+) leak.

  5. Alternancia de lenguas como estrategia de actividad de imagen en la comunicación médico-paciente en un consultorio gallego

    Directory of Open Access Journals (Sweden)

    Vanesa Rodríguez Tembrás

    2016-07-01

    Full Text Available Este trabajo explora la alternancia de lenguas desde un enfoque sociopragmático, entendiendo este fenómeno como estrategia de actividad de imagen en la interacción médico-paciente en Galicia (España, una comunidad de habla bilingüe. El corpus utilizado está formado por grabaciones de audio y entrevistas de profundización en un centro de atención primaria en esta comunidad autónoma, donde el gallego y el castellano son lenguas cooficiales. El 95.8% de la población afirma entender el gallego y el 86.9% lo habla a un nivel alto. Esta investigación es la primera aproximación a porqué los médicos y los pacientes realizan alternancia de lenguas, cuando aparentemente no existe una necesidad derivada de una carencia de competencia lingüística. Nuestra hipótesis es que los hablantes realizan otras estrategias pragmáticas, como es la actividad de imagen, con el fin de (redefinir o (reconstruir su identidad cuando alternan lenguas. Para investigar esto, hemos analizado dos secuencias con el mismo médico. En la primera, tanto el doctor como la paciente realizan alternancia de lenguas del castellano al gallego como estrategias de cortesía por afiliación y de autoimagen. En la segunda secuencia solo la paciente alterna lenguas del gallego al castellano como actividad de autoimagen.

  6. Radiation myelopathy

    International Nuclear Information System (INIS)

    Berlit, P.

    1987-01-01

    After a review of the world literature, the case histories of 43 patients with radiation myelopathy are analyzed. In 1 patient there was a radiation injury of the medulla oblongata, in 2, cervical, in 28, thoracic, and in 12, lumbosacral. In the medulla oblongata lesion an alternans syndrome resulted. The patients with cervical and thoracic radiation myelopathies presented with a Brown-Sequard syndrome, a spinalis anterior syndrome or a transversal syndrome with pyramidal and spinothalamic tract involvement as the most prominent signs. For this group the term 'pyramidal-spinothalamic radiation myelopathy' is proposed. In lumbosacral radiation lesions a pure anterior horn syndrome may lead to spinothalamic tract involvement and the development of a cauda conus syndrome. The clinical presentation of these cases suggests that the location of the radiation lesion is most likely the region of the conus medullaris. The most frequent initial symptom was dysesthesia; the patients complained of burning pain or a feeling of coldness. Usually the neurological deficits were progressive, in pyramidal-spinothalamic radiation myelopathy over 12 months in average, in lumbosacral radiation lesions up to 10 years. The latent period between the finish of radiation therapy and the first neurological signs was 8 months (median) in cervical and thoracic myelopathy and 33 months in lumbosacral lesions. For the entire group of 43 patients there was an inverse relationship between the radiation dose (ret) and the latent period. A positive relation could be demonstrated between the age of patients at the time of radiation therapy and the latent period. Patients simultaneously receiving cytostatic drugs presented after a longer latent period than the remaining group. (orig./MG)

  7. Improved preclinical cardiovascular therapeutic indices with long-term inhibition of norepinephrine reuptake using reboxetine

    International Nuclear Information System (INIS)

    Fossa, Anthony A.; Wisialowski, Todd A.; Cremers, Thomas; Hart, Marieke van der; Tseng, Elaine; Deng, Shibing; Rollema, Hans; Wang, Ellen Q.

    2012-01-01

    Norepinephrine reuptake inhibitors (NRIs) acutely increase norepinephrine (NE) levels, but therapeutic antidepressant activity is only observed after weeks of treatment because central NE levels progressively increase during continued drug exposure. Similarly, while NRIs acutely increase blood pressure (BP) and heart rate (HR) due to enhanced sympathetic neurotransmission, chronic treatment changes the responsiveness of the central noradrenergic system and suppresses these effects via autonomic regulation. To better understand the relationship between NE increases and cardiovascular safety, we investigated acute and chronic effects of the NRI reboxetine on central NE release and on BP and HR and electrical alternans, a measure of arrhythmia liability, in guinea pigs. NE release was assessed by microdialysis in medial prefrontal cortex (mPFC) and hypothalamic paraventricular nucleus (PVN); BP and HR were measured by telemetry. Animals were treated for 28 days with 15 mg/kg/day of reboxetine or vehicle via an osmotic minipump and then challenged with acute intravenous doses of reboxetine. Animals chronically treated with reboxetine had 2-fold higher extracellular basal NE levels in mPFC and PVN compared to basal levels after chronic vehicle treatment. BP was significantly increased after the first day of treatment, and gradually returned to vehicle levels by day 21. These data indicate that chronic NRI treatment may lead to an increase in central NE levels and a concomitant reduction in BP based on exposure–response curves compared to vehicle treatment, suggesting a larger separation between preclinical estimates of efficacy vs. safety compared to acute NRI treatment. -- Highlights: ► Acute RBX produces blood pressure increases acutely that decrease with chronic RBX ► Chronic RBX increases brain NE levels, a preclinical surrogate of improved efficacy ► Short-term screening of NRI often underestimates the chronic therapeutic index ► Chronic cardiovascular

  8. Improved preclinical cardiovascular therapeutic indices with long-term inhibition of norepinephrine reuptake using reboxetine

    Energy Technology Data Exchange (ETDEWEB)

    Fossa, Anthony A., E-mail: anthony.fossa@icardiac.com [Department of Global Safety Pharmacology, Department of Pharmacokinetics, Dynamics and Metabolism, and Neuroscience, Pfizer Global Research and Development Eastern Point Road, Groton, CT 06340 (United States); Wisialowski, Todd A. [Department of Global Safety Pharmacology, Department of Pharmacokinetics, Dynamics and Metabolism, and Neuroscience, Pfizer Global Research and Development Eastern Point Road, Groton, CT 06340 (United States); Cremers, Thomas; Hart, Marieke van der [Brains On-Line B.V., University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen (Netherlands); Tseng, Elaine; Deng, Shibing; Rollema, Hans; Wang, Ellen Q. [Department of Global Safety Pharmacology, Department of Pharmacokinetics, Dynamics and Metabolism, and Neuroscience, Pfizer Global Research and Development Eastern Point Road, Groton, CT 06340 (United States)

    2012-11-01

    Norepinephrine reuptake inhibitors (NRIs) acutely increase norepinephrine (NE) levels, but therapeutic antidepressant activity is only observed after weeks of treatment because central NE levels progressively increase during continued drug exposure. Similarly, while NRIs acutely increase blood pressure (BP) and heart rate (HR) due to enhanced sympathetic neurotransmission, chronic treatment changes the responsiveness of the central noradrenergic system and suppresses these effects via autonomic regulation. To better understand the relationship between NE increases and cardiovascular safety, we investigated acute and chronic effects of the NRI reboxetine on central NE release and on BP and HR and electrical alternans, a measure of arrhythmia liability, in guinea pigs. NE release was assessed by microdialysis in medial prefrontal cortex (mPFC) and hypothalamic paraventricular nucleus (PVN); BP and HR were measured by telemetry. Animals were treated for 28 days with 15 mg/kg/day of reboxetine or vehicle via an osmotic minipump and then challenged with acute intravenous doses of reboxetine. Animals chronically treated with reboxetine had 2-fold higher extracellular basal NE levels in mPFC and PVN compared to basal levels after chronic vehicle treatment. BP was significantly increased after the first day of treatment, and gradually returned to vehicle levels by day 21. These data indicate that chronic NRI treatment may lead to an increase in central NE levels and a concomitant reduction in BP based on exposure–response curves compared to vehicle treatment, suggesting a larger separation between preclinical estimates of efficacy vs. safety compared to acute NRI treatment. -- Highlights: ► Acute RBX produces blood pressure increases acutely that decrease with chronic RBX ► Chronic RBX increases brain NE levels, a preclinical surrogate of improved efficacy ► Short-term screening of NRI often underestimates the chronic therapeutic index ► Chronic cardiovascular

  9. Inhibiting Na+/K+ ATPase can impair mitochondrial energetics and induce abnormal Ca2+ cycling and automaticity in guinea pig cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Qince Li

    Full Text Available Cardiac glycosides have been used for the treatment of heart failure because of their capabilities of inhibiting Na+/K+ ATPase (NKA, which raises [Na+]i and attenuates Ca2+ extrusion via the Na+/Ca2+ exchanger (NCX, causing [Ca2+]i elevation. The resulting [Ca2+]i accumulation further enhances Ca2+-induced Ca2+ release, generating the positive inotropic effect. However, cardiac glycosides have some toxic and side effects such as arrhythmogenesis, confining their extensive clinical applications. The mechanisms underlying the proarrhythmic effect of glycosides are not fully understood. Here we investigated the mechanisms by which glycosides could cause cardiac arrhythmias via impairing mitochondrial energetics using an integrative computational cardiomyocyte model. In the simulations, the effect of glycosides was mimicked by blocking NKA activity. Results showed that inhibiting NKA not only impaired mitochondrial Ca2+ retention (thus suppressed reactive oxygen species (ROS scavenging but also enhanced oxidative phosphorylation (thus increased ROS production during the transition of increasing workload, causing oxidative stress. Moreover, concurrent blocking of mitochondrial Na+/Ca2+ exchanger, but not enhancing of Ca2+ uniporter, alleviated the adverse effects of NKA inhibition. Intriguingly, NKA inhibition elicited Ca2+ transient and action potential alternans under more stressed conditions such as severe ATP depletion, augmenting its proarrhythmic effect. This computational study provides new insights into the mechanisms underlying cardiac glycoside-induced arrhythmogenesis. The findings suggest that targeting both ion handling and mitochondria could be a very promising strategy to develop new glycoside-based therapies in the treatment of heart failure.

  10. Inhibiting Na+/K+ ATPase can impair mitochondrial energetics and induce abnormal Ca2+ cycling and automaticity in guinea pig cardiomyocytes.

    Science.gov (United States)

    Li, Qince; Pogwizd, Steven M; Prabhu, Sumanth D; Zhou, Lufang

    2014-01-01

    Cardiac glycosides have been used for the treatment of heart failure because of their capabilities of inhibiting Na+/K+ ATPase (NKA), which raises [Na+]i and attenuates Ca2+ extrusion via the Na+/Ca2+ exchanger (NCX), causing [Ca2+]i elevation. The resulting [Ca2+]i accumulation further enhances Ca2+-induced Ca2+ release, generating the positive inotropic effect. However, cardiac glycosides have some toxic and side effects such as arrhythmogenesis, confining their extensive clinical applications. The mechanisms underlying the proarrhythmic effect of glycosides are not fully understood. Here we investigated the mechanisms by which glycosides could cause cardiac arrhythmias via impairing mitochondrial energetics using an integrative computational cardiomyocyte model. In the simulations, the effect of glycosides was mimicked by blocking NKA activity. Results showed that inhibiting NKA not only impaired mitochondrial Ca2+ retention (thus suppressed reactive oxygen species (ROS) scavenging) but also enhanced oxidative phosphorylation (thus increased ROS production) during the transition of increasing workload, causing oxidative stress. Moreover, concurrent blocking of mitochondrial Na+/Ca2+ exchanger, but not enhancing of Ca2+ uniporter, alleviated the adverse effects of NKA inhibition. Intriguingly, NKA inhibition elicited Ca2+ transient and action potential alternans under more stressed conditions such as severe ATP depletion, augmenting its proarrhythmic effect. This computational study provides new insights into the mechanisms underlying cardiac glycoside-induced arrhythmogenesis. The findings suggest that targeting both ion handling and mitochondria could be a very promising strategy to develop new glycoside-based therapies in the treatment of heart failure.

  11. Radiation myelopathy. Analysis of the clinical picture. Die Strahlenmyelopathie. Klinische Analyse des Krankheitsbildes

    Energy Technology Data Exchange (ETDEWEB)

    Berlit, P

    1987-01-01

    After a review of the world literature, the case histories of 43 patients with radiation myelopathy are analyzed. In 1 patient there was a radiation injury of the medulla oblongata, in 2, cervical, in 28, thoracic, and in 12, lumbosacral. In the medulla oblongata lesion an alternans syndrome resulted. The patients with cervical and thoracic radiation myelopathies presented with a Brown-Sequard syndrome, a spinalis anterior syndrome or a transversal syndrome with pyramidal and spinothalamic tract involvement as the most prominent signs. For this group the term 'pyramidal-spinothalamic radiation myelopathy' is proposed. In lumbosacral radiation lesions a pure anterior horn syndrome may lead to spinothalamic tract involvement and the development of a cauda conus syndrome. The clinical presentation of these cases suggests that the location of the radiation lesion is most likely the region of the conus medullaris. The most frequent initial symptom was dysesthesia; the patients complained of burning pain or a feeling of coldness. Usually the neurological deficits were progressive, in pyramidal-spinothalamic radiation myelopathy over 12 months in average, in lumbosacral radiation lesions up to 10 years. The latent period between the finish of radiation therapy and the first neurological signs was 8 months (median) in cervical and thoracic myelopathy and 33 months in lumbosacral lesions. For the entire group of 43 patients there was an inverse relationship between the radiation dose (ret) and the latent period. A positive relation could be demonstrated between the age of patients at the time of radiation therapy and the latent period. Patients simultaneously receiving cytostatic drugs presented after a longer latent period than the remaining group. With 17 figs.

  12. Electrocardiographic features of patients with earthquake related posttraumatic stress disorder

    Science.gov (United States)

    İlhan, Erkan; Kaplan, Abdullah; Güvenç, Tolga Sinan; Biteker, Murat; Karabulut, Evindar; Işıklı, Serhan

    2013-01-01

    AIM: To analyze electrocardiographic features of patients diagnosed with posttraumatic stress disorder (PTSD) after the Van-Erciş earthquake, with a shock measuring 7.2 on the Richter scale that took place in Turkey in October 2011. METHODS: Surface electrocardiograms of 12 patients with PTSD admitted to Van Erciş State Hospital (Van, Turkey) from February 2012 to May 2012 were examined. Psychiatric interviews of the sex and age matched control subjects, who had experienced the earthquake, confirmed the absence of any known diagnosable psychiatric conditions in the control group. RESULTS: A wide range of electrocardiogram (ECG) parameters, such as P-wave dispersion, QT dispersion, QT interval, Tpeak to Tend interval, intrinsicoid deflection durations and other traditional parameters were similar in both groups. There was no one with an abnormal P wave axis, short or long PR interval, long or short QT interval, negative T wave in lateral leads, abnormal T wave axis, abnormal left or right intrinsicoid deflection duration, low voltage, left bundle branch block, right bundle branch block, left posterior hemiblock, left or right axis deviation, left ventricular hypertrophy, right or left atrial enlargement and pathological q(Q) wave in either group. CONCLUSION: The study showed no direct effect of earthquake related PTSD on surface ECG in young patients. So, we propose that PTSD has no direct effect on surface ECG but may cause electrocardiographic changes indirectly by triggering atherosclerosis and/or contributing to the ongoing atherosclerotic process. PMID:23538549

  13. Basal wall hypercontraction of Takotsubo cardiomyopathy in a patient who had been diagnosed with dilated cardiomyopathy: a case report.

    Science.gov (United States)

    Ichihara, Noboru; Fujita, Shuichi; Kanzaki, Yumiko; Fujisaka, Tomohiro; Ozeki, Michishige; Ishizaka, Nobukazu

    2017-12-12

    Takotsubo cardiomyopathy is characterized by the basal hypercontractility and apical ballooning of the left ventriculum and T-wave inversion in the electrocardiogram. It has been suggested that Takotsubo cardiomyopathy might underlie the pathogenesis of persistent cardiac dysfunction; however, few reports are present demonstrating the advent of Takotsubo cardiomyopathy in patients with idiopathic cardiomyopathy. A 64-year-old women was admitted due to dyspnea on effort and lower extremity edema. She had been diagnosed with idiopathic dilated cardiomyopathy 2.5 years before owing to the reduced left ventricular ejection fraction (24%), normal coronary artery, and interstitial fibrosis of the myocardial samples. On admission, her electrocardiogram showed giant negative T wave in II, III, aVF, and precordial leads. Echocardiography showed dyskinesis of the left ventricular apex and hypercontraction of the basal wall, which had not been observed in the previous examinations. Coronary angiography showed normal coronary arteries, and apical ballooning and basal hypercontractility was confirmed by left ventriculography. On day 15 of admission, contraction of apical wall was recovered, and basal hypercontraction was disappeared. The present case is the first report demonstrating appearance the transient basal wall hypercontraction along with the advent of Takotsubo cardiomyopathy in a patient diagnosed with dilated cardiomyopathy. Whether such findings are indicative of fair prognosis and have the utility of understanding the pathogenesis of dilated cardiomyopathy needs further investigation.

  14. Quantitative performance of E-Scribe warehouse in detecting quality issues with digital annotated ECG data from healthy subjects.

    Science.gov (United States)

    Sarapa, Nenad; Mortara, Justin L; Brown, Barry D; Isola, Lamberto; Badilini, Fabio

    2008-05-01

    The US Food and Drug Administration recommends submission of digital electrocardiograms in the standard HL7 XML format into the electrocardiogram warehouse to support preapproval review of new drug applications. The Food and Drug Administration scrutinizes electrocardiogram quality by viewing the annotated waveforms and scoring electrocardiogram quality by the warehouse algorithms. Part of the Food and Drug Administration warehouse is commercially available to sponsors as the E-Scribe Warehouse. The authors tested the performance of E-Scribe Warehouse algorithms by quantifying electrocardiogram acquisition quality, adherence to QT annotation protocol, and T-wave signal strength in 2 data sets: "reference" (104 digital electrocardiograms from a phase I study with sotalol in 26 healthy subjects with QT annotations by computer-assisted manual adjustment) and "test" (the same electrocardiograms with an intentionally introduced predefined number of quality issues). The E-Scribe Warehouse correctly detected differences between the 2 sets expected from the number and pattern of errors in the "test" set (except for 1 subject with QT misannotated in different leads of serial electrocardiograms) and confirmed the absence of differences where none was expected. E-Scribe Warehouse scores below the threshold value identified individual electrocardiograms with questionable T-wave signal strength. The E-Scribe Warehouse showed satisfactory performance in detecting electrocardiogram quality issues that may impair reliability of QTc assessment in clinical trials in healthy subjects.

  15. The effect of sport on computerized electrocardiogram measurements in college athletes.

    Science.gov (United States)

    Gademan, Maaike G J; Uberoi, Abhimanyu; Le, Vy-Van; Mandic, Sandra; van Oort, Eddy R; Myers, Jonathan; Froelicher, Victor F

    2012-02-01

    Broad criteria for abnormal electrocardiogram (ECG) findings, requiring additional testing, have been recommended for preparticipation exams (PPE) of athletes. As these criteria have not considered the sport in which athletes participate, we examined the effect of sports on the computerized ECG measurements obtained in college athletes. During the Stanford 2007 PPE, computerized 12-lead ECGs (Schiller AG) were obtained in 641 athletes (350 male/291 female, age 19.5 ± 2 years). Athletes were engaged in 22 different sports and were grouped into 16 categories: baseball/softball, basketball, crew, crosscountry, fencing, field events, football linemen, football other positions, golf, gymnastics, racquet sports, sailing, track/field, volleyball, water sports, and wrestling. The analysis focused on ECG leads V2, aVF and V5 which provide a three-dimensional representation of the heart's electrical activity. As marked ECG differences exist between males and females, the data are presented by gender. In males, ANOVA analysis yielded significant ECG differences between sports for heart rate, QRS duration, QTc, J-amplitude in V2 and V5, spatial vector length (SVL) of the P wave, SVL R wave, and SVL T wave, and RS(sum) (p sports were found for heart rate, QRS duration, QRS axis and SVL T wave (p sports, and these differences were more apparent in males than females. Therefore, sport-specific ECG criteria for abnormal ECG findings should be developed to obtain a more useful approach to ECG screening in athletes.

  16. Congenital short QT syndrome and implantable cardioverter defibrillator treatment: inherent risk for inappropriate shock delivery.

    Science.gov (United States)

    Schimpf, Rainer; Wolpert, Christian; Bianchi, Francesca; Giustetto, Carla; Gaita, Florenzo; Bauersfeld, Urs; Borggrefe, Martin

    2003-12-01

    A congenital short QT interval constitutes a new primary electrical abnormality associated with syncope and/or sudden cardiac death. We report on the initial use of implantable cardioverter defibrillator (ICD) therapy in patients with inherited short QT interval and discuss sensing abnormalities and detection issues. In five consecutive patients from two unrelated European families who had structurally normal hearts, excessively shortened QT intervals, and a strong positive family history of sudden cardiac death, ICDs were placed for primary and secondary prevention. Mean QT intervals were 252 +/- 13 ms (QTc 287 +/- 13 ms). Despite normal sensing behavior during intraoperative and postoperative device testing, 3 of 5 patients experienced inappropriate shock therapies for T wave oversensing 30 +/- 26 days after implantation. Programming lower sensitivities and decay delays prevented further inappropriate discharges. The congenital short QT syndrome constitutes a new clinical entity with an increased risk for sudden cardiac death. Currently, ICD treatment is the only therapeutic option. In patients with short QT interval and implanted ICD, increased risk for inappropriate therapy is inherent due to the detection of short-coupled and prominent T waves. Careful testing of ICD function and adaptation of sensing levels and decay delays without sacrificing correct arrhythmia detection are essential.

  17. Twelve-lead electrocardiography in the young: physiologic and pathologic abnormalities.

    Science.gov (United States)

    Kobza, Richard; Cuculi, Florim; Abächerli, Roger; Toggweiler, Stefan; Suter, Yves; Frey, Franz; Schmid, Johann Jakob; Erne, Paul

    2012-12-01

    BACKGROUND/ OBJECTIVE: The purpose of the present study was to analyze the prevalence of physiologic and pathologic ECG abnormalities in a cohort of young conscripts that represents the whole young generation of today. ECGs of all Swiss citizens who underwent conscription for the army during a 29-month period were analyzed manually. ECGs of 43,401 conscripts (mean age 19.2 ± 1.1 years) were analyzed; 158 conscripts were female. Incomplete right bundle branch block was found in 5870 (13.5%) and left anterior fascicular block in 360 (0.83%). First-degree AV block was present in 329 (0.8%) and Mobitz type I (Wenckebach) second-degree AV block in 3 (0.01%). Early repolarization was observed in 1035 (2.4%), T-wave inversion in 39 (0.09%), and minor T-wave changes in 182 (0.42%). Brugada-like abnormalities were observed in 6 (0.01%). None of the conscripts had atrial fibrillation or flutter. ECG abnormalities can be found in a relatively large proportion of young individuals. Incomplete right bundle branch block, left fascicular block, and first-degree AV block are the most frequent findings. No conscript presented with atrial fibrillation or flutter. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  18. Complete regression of myocardial involvement associated with lymphoma following chemotherapy.

    Science.gov (United States)

    Vinicki, Juan Pablo; Cianciulli, Tomás F; Farace, Gustavo A; Saccheri, María C; Lax, Jorge A; Kazelian, Lucía R; Wachs, Adolfo

    2013-09-26

    Cardiac involvement as an initial presentation of malignant lymphoma is a rare occurrence. We describe the case of a 26 year old man who had initially been diagnosed with myocardial infiltration on an echocardiogram, presenting with a testicular mass and unilateral peripheral facial paralysis. On admission, electrocardiograms (ECG) revealed negative T-waves in all leads and ST-segment elevation in the inferior leads. On two-dimensional echocardiography, there was infiltration of the pericardium with mild effusion, infiltrative thickening of the aortic walls, both atria and the interatrial septum and a mildly depressed systolic function of both ventricles. An axillary biopsy was performed and reported as a T-cell lymphoblastic lymphoma (T-LBL). Following the diagnosis and staging, chemotherapy was started. Twenty-two days after finishing the first cycle of chemotherapy, the ECG showed regression of T-wave changes in all leads and normalization of the ST-segment elevation in the inferior leads. A follow-up Two-dimensional echocardiography confirmed regression of the myocardial infiltration. This case report illustrates a lymphoma presenting with testicular mass, unilateral peripheral facial paralysis and myocardial involvement, and demonstrates that regression of infiltration can be achieved by intensive chemotherapy treatment. To our knowledge, there are no reported cases of T-LBL presenting as a testicular mass and unilateral peripheral facial paralysis, with complete regression of myocardial involvement.

  19. New micro waveforms firstly recorded on electrocardiogram in human.

    Science.gov (United States)

    Liu, Renguang; Chang, Qinghua; Chen, Juan

    2015-10-01

    In our study, not only the P-QRS-T waves but also the micro-wavelets before QRS complex (in P wave and PR segment) and after QRS complex (ST segment and upstroke of T wave) were first to be identified on surface electrocardiogram in human by the "new electrocardiogram" machine (model PHS-A10) according to conventional 12-lead electrocardiogram connection methods. By comparison to the conventional electrocardiogram in 100 cases of healthy individuals and several patients with arrhythmias, we have found that the wavelets before P wave theoretically reflected electrical activity of sinus node and the micro-wavelets before QRS complex may be related to atrioventricular conduction system (atrioventricular node, His bundle and bundle branch) potentials. Noninvasive atrioventricular node and His bundle potential tracing will contribute to differentiation of the origin of wide QRS and the location of the atrioventricular block. We also have found that the wavelets after QRS complex may be associated with phase 2 and 3 repolarization of ventricular action potential, which will further reveal ventricular repolarization changes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Conventional QT Variability Measurement vs. Template Matching Techniques: Comparison of Performance Using Simulated and Real ECG

    Science.gov (United States)

    Baumert, Mathias; Starc, Vito; Porta, Alberto

    2012-01-01

    Increased beat-to-beat variability in the QT interval (QTV) of ECG has been associated with increased risk for sudden cardiac death, but its measurement is technically challenging and currently not standardized. The aim of this study was to investigate the performance of commonly used beat-to-beat QT interval measurement algorithms. Three different methods (conventional, template stretching and template time shifting) were subjected to simulated data featuring typical ECG recording issues (broadband noise, baseline wander, amplitude modulation) and real short-term ECG of patients before and after infusion of sotalol, a QT interval prolonging drug. Among the three algorithms, the conventional algorithm was most susceptible to noise whereas the template time shifting algorithm showed superior overall performance on simulated and real ECG. None of the algorithms was able to detect increased beat-to-beat QT interval variability after sotalol infusion despite marked prolongation of the average QT interval. The QTV estimates of all three algorithms were inversely correlated with the amplitude of the T wave. In conclusion, template matching algorithms, in particular the time shifting algorithm, are recommended for beat-to-beat variability measurement of QT interval in body surface ECG. Recording noise, T wave amplitude and the beat-rejection strategy are important factors of QTV measurement and require further investigation. PMID:22860030

  1. Conventional QT variability measurement vs. template matching techniques: comparison of performance using simulated and real ECG.

    Directory of Open Access Journals (Sweden)

    Mathias Baumert

    Full Text Available Increased beat-to-beat variability in the QT interval (QTV of ECG has been associated with increased risk for sudden cardiac death, but its measurement is technically challenging and currently not standardized. The aim of this study was to investigate the performance of commonly used beat-to-beat QT interval measurement algorithms. Three different methods (conventional, template stretching and template time shifting were subjected to simulated data featuring typical ECG recording issues (broadband noise, baseline wander, amplitude modulation and real short-term ECG of patients before and after infusion of sotalol, a QT interval prolonging drug. Among the three algorithms, the conventional algorithm was most susceptible to noise whereas the template time shifting algorithm showed superior overall performance on simulated and real ECG. None of the algorithms was able to detect increased beat-to-beat QT interval variability after sotalol infusion despite marked prolongation of the average QT interval. The QTV estimates of all three algorithms were inversely correlated with the amplitude of the T wave. In conclusion, template matching algorithms, in particular the time shifting algorithm, are recommended for beat-to-beat variability measurement of QT interval in body surface ECG. Recording noise, T wave amplitude and the beat-rejection strategy are important factors of QTV measurement and require further investigation.

  2. Prevalence of electrocardiographic changes in patients with acute aneurysmal subarachnoid hemorrhage and their relationship with outcome

    Directory of Open Access Journals (Sweden)

    Saktheeswaran Mahesh Kumar

    2013-01-01

    Full Text Available Background: Electrocardiographic (ECG alterations occurring after subarachnoid hemorrhage (SAH have been described frequently, but the prognostic significance of these changes has not been well characterized. Aim and Objectives: To report the prevalence and patterns of ECG alterations in patients with acute aneurysmal SAH and to study the relationship between ECG alterations and the neurological outcome, if any. Materials and Methods: Records of consecutive patients admitted to the neurosurgical intensive care unit of the SCTIMST, Trivandrum between January 1999 and January 2011 with acute aneurysmal SAH were retrospectively analyzed. Results: Of the 321 patients with SAH, 190 (59.2% had abnormal ECGs. Repolarization abnormalities were the most common, with T wave inversion in the anterolateral leads occurring in 155 (48.3% patients. By univariate analysis, female sex, Glasgow Coma Score (GCS at admission of I, ST segment depression or T inversion in anterolateral leads, prolonged corrected QT interval, and sinus bradycardia were associated with increased risk of death. By multivariate analysis, only GCS and WFNS grade independently predicted mortality and none of the ECG changes predicted the same. Presence of tall T waves in anterior leads, T inversion in anterolateral leads, sinus bradycardia, and WFNS grade >1 were independently associated with GCS <15 and poor outcome at discharge. Conclusions: In patients with acute aneurysmal SAH, repolarization abnormalities are the commonest ECG alterations. ECG alterations do not independently predict death, but independently predict poor discharge neurological status.

  3. Thiolated polymers--thiomers: development and in vitro evaluation of chitosan-thioglycolic acid conjugates.

    Science.gov (United States)

    Kast, C E; Bernkop-Schnürch, A

    2001-09-01

    The aim of this study was to improve mucoadhesive properties of chitosan by the covalent attachment of thiol moieties to this cationic polymer. Mediated by a carbodiimide, thioglycolic acid (TGA) was covalently attached to chitosan. This was achieved by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid group of TGA. Dependent on the pH-value and the weight ratio of polymer to TGA during the coupling reaction the resulting thiolated polymers, the so-called thiomers, displayed 6.58, 9.88, 27.44, and 38.23 micromole thiol groups per gram polymer. Tensile studies carried out with these chitosan-TGA conjugates on freshly excised porcine intestinal mucosa demonstrated a 6.3-, 8.6-, 8.9-, and 10.3-fold increase in the total work of adhesion (TWA) compared to the unmodified polymer, respectively. In contrast, the combination of chitosan and free unconjugated TGA showed almost no mucoadhesion. These data were in good correlation with further results obtained by another mucoadhesion test demonstrating a prolonged residence time of thiolated chitosan on porcine mucosa. The swelling behavior of all conjugates was thereby exactly in the same range as for an unmodified polymer pretreated in the same way. Furthermore, it could be shown that chitosan-TGA conjugates are still biodegradable by the glycosidase lysozyme. According to these results. chitosan-TGA conjugates represent a promising tool for the development of mucoadhesive drug delivery systems.

  4. Mucoadhesive polymers: Synthesis and in vitro characterization of thiolated poly(vinyl alcohol).

    Science.gov (United States)

    Suchaoin, Wongsakorn; Pereira de Sousa, Irene; Netsomboon, Kesinee; Rohrer, Julia; Hoffmann Abad, Patricia; Laffleur, Flavia; Matuszczak, Barbara; Bernkop-Schnürch, Andreas

    2016-04-30

    The aim of this study was to synthesize thiolated poly(vinyl alcohol) (PVA) and to evaluate its mucoadhesive properties. Thiourea and 3-mercaptopropionic acid were utilized in order to obtain thiolated PVAs, namely, TPVA1 and TPVA2, respectively. TPVA1 and TPVA2 displayed 130.44 ± 14.99 and 958.35 ± 155.27 μmol immobilized thiol groups per gram polymer, respectively, which were then evaluated regarding reactivity of thiol groups, swelling behavior and mucoadhesive properties. Both thiolated PVAs exhibited the highest reactivity at pH 8.0 whereas more than 95% of free thiol groups were preserved at pH 5.0. Thiolation of PVA decelerated water uptake and prolonged disintegration time of test discs compared to unmodified PVA. Contact time of TPVA1- and TPVA2-based test discs on porcine intestinal mucosa was 3.2- and 15.8-fold prolonged, respectively, in comparison to non-thiolated PVA as measured by rotating cylinder method. According to tensile studies on mucosa, the total work of adhesion (TWA) and the maximum detachment force (MDF) were increased when compared to PVA. Furthermore, thiolated PVAs preserved higher percentage of viable cells compared to unmodified PVA within 24h as evaluated by MTT assay. Accordingly, thiolated PVA represents a novel excipient that can likely improve the mucoadhesive properties of various pharmaceutical formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. [Occupational exposure to hexavalent chromium during aircraft painting].

    Science.gov (United States)

    Gherardi, M; Gatto, M P; Gordiani, A; Paci, E; Proietto, A

    2007-01-01

    Hygienists are interested in hexavalent chromium due to its genotoxic and carcinogenic effect on humans. The use of products containing hexavalent chromium is decreasing in many industrial fields because of the substitution with less-toxic compounds. In the aeronautical industry, however, the chromate are added to primer paint as a corrosion inhibitor of aircrafts surfaces: so hexavalent chromium compounds are available in many primers with a composition ranging from 10% to 13%. The application of these primers by using electrostatic guns potentially exposes painting and coating workers at high concentrations of aerosols containing Cr(VI). The aim of the present study is the evaluation of professional exposure to hexavalent chromium during aircraft painting, by adopting both environmental personal sampling and biological monitoring. To valuate workers exposure levels the personal measurements results have been compared with the exposure limit values (TLV-TWA) and the urinary chromium contents with the biological exposure indices (IBE). Moreover the strategy of coupling environmental sampling with biological monitoring seems to be a useful instrument to measure the validity of the individual protection devices.

  6. Lithium in drinking water and incidence of suicide

    DEFF Research Database (Denmark)

    Knudsen, Nikoline N.; Schullehner, Jörg; Hansen, Birgitte

    2017-01-01

    Suicide is a major public health concern. High-dose lithium is used to stabilize mood and prevent suicide in patients with affective disorders. Lithium occurs naturally in drinking water worldwide in much lower doses, but with large geographical variation. Several studies conducted at an aggregate...... level have suggested an association between lithium in drinking water and a reduced risk of suicide; however, a causal relation is uncertain. Individual-level register-based data on the entire Danish adult population (3.7 million individuals) from 1991 to 2012 were linked with a moving five-year time......-weighted average (TWA) lithium exposure level from drinking water hypothesizing an inverse relationship. The mean lithium level was 11.6 µg/L ranging from 0.6 to 30.7 µg/L. The suicide rate decreased from 29.7 per 100,000 person-years at risk in 1991 to 18.4 per 100,000 person-years in 2012. We found...

  7. Seasonal occurrence of antibiotics and a beta agonist in an agriculturally-intensive watershed

    International Nuclear Information System (INIS)

    Jaimes-Correa, Juan C.; Snow, Daniel D.; Bartelt-Hunt, Shannon L.

    2015-01-01

    We evaluated the occurrence of 12 veterinary antibiotics and a beta agonist over spatial and temporal scales in Shell Creek, an intensively agricultural watershed in Nebraska, using Polar Organic Chemical Integrative Samplers (POCIS). Twelve pharmaceuticals were detected with concentrations ranging from 0.0003 ng/L to 68 ng/L. The antibiotics measured at the highest time-weighted average concentrations were lincomycin (68 ng/L) and monensin (49 ng/L), and both compounds were detected at increased concentrations in summer months. Analysis of variance indicates that mean concentrations of detected pharmaceuticals have no significant (p > 0.01) spatial variation. However, significant temporal differences (p < 0.01) were observed. This study demonstrates the utility of passive samplers such as POCIS for monitoring ambient levels of pharmaceuticals in surface waters. - Highlights: • Passive samplers were used to evaluate veterinary pharmaceuticals in an agricultural watershed. • Monensin and lincomycin were detected at the highest TWA concentrations. • Significantly higher concentrations were detected in summer months. • Pulses of antibiotics correspond with rainfall-runoff events. - The spatial and temporal differences in the occurrence of thirteen veterinary pharmaceuticals was evaluated in an intensively agricultural watershed

  8. Strain sensing systems tailored for tensile measurement of fragile wires

    Science.gov (United States)

    Nyilas, Arman

    2005-12-01

    Fundamental stress versus strain measurements were completed on superconducting Nb3Sn wires within the framework of IEC/TC90 and VAMAS/TWA16. A key task was the assessment of sensing systems regarding resolution, accuracy, and precision when measuring Young's modulus. Prior to actual Nb3Sn wire measurements metallic wires, consisting of copper and stainless steel having diameters similar to the Nb3Sn wire, were extensively investigated with respect to their elastic line properties using different types of extensometers. After these calibration tests Nb3Sn wire measurements of different companies resulted in several important facts with respect to total size and weight of the used extensometers. The size could be correlated to the initial stage of stress versus strain behaviour. In fact, the effect of wire curls resulting from the production line had a profound effect on Young's modulus measurements. Within this context, the possibility of determining Young's modulus from unloading compliance lines in the plastic regime of the stress-strain curve was considered. The data obtained using this test methodology were discussed under consideration of the composite nature of Nb3Sn wire. In addition, a non-contacting sensing system based on a double-beam laser extensometer was used to investigate the potential of this new sensing system.

  9. Strain sensing systems tailored for tensile measurement of fragile wires

    International Nuclear Information System (INIS)

    Nyilas, Arman

    2005-01-01

    Fundamental stress versus strain measurements were completed on superconducting Nb 3 Sn wires within the framework of IEC/TC90 and VAMAS/TWA16. A key task was the assessment of sensing systems regarding resolution, accuracy, and precision when measuring Young's modulus. Prior to actual Nb 3 Sn wire measurements metallic wires, consisting of copper and stainless steel having diameters similar to the Nb 3 Sn wire, were extensively investigated with respect to their elastic line properties using different types of extensometers. After these calibration tests Nb 3 Sn wire measurements of different companies resulted in several important facts with respect to total size and weight of the used extensometers. The size could be correlated to the initial stage of stress versus strain behaviour. In fact, the effect of wire curls resulting from the production line had a profound effect on Young's modulus measurements. Within this context, the possibility of determining Young's modulus from unloading compliance lines in the plastic regime of the stress-strain curve was considered. The data obtained using this test methodology were discussed under consideration of the composite nature of Nb 3 Sn wire. In addition, a non-contacting sensing system based on a double-beam laser extensometer was used to investigate the potential of this new sensing system

  10. Associations between Bisphenol A Exposure and Reproductive Hormones among Female Workers

    Directory of Open Access Journals (Sweden)

    Maohua Miao

    2015-10-01

    Full Text Available The associations between Bisphenol-A (BPA exposure and reproductive hormone levels among women are unclear. A cross-sectional study was conducted among female workers from BPA-exposed and unexposed factories in China. Women’s blood samples were collected for assay of follicle-stimulating hormone (FSH, luteinizing hormone (LH, 17β-Estradiol (E2, prolactin (PRL, and progesterone (PROG. Their urine samples were collected for BPA measurement. In the exposed group, time weighted average exposure to BPA for an 8-h shift (TWA8, a measure incorporating historic exposure level, was generated based on personal air sampling. Multiple linear regression analyses were used to examine linear associations between urine BPA concentration and reproductive hormones after controlling for potential confounders. A total of 106 exposed and 250 unexposed female workers were included in this study. A significant positive association between increased urine BPA concentration and higher PRL and PROG levels were observed. Similar associations were observed after the analysis was carried out separately among the exposed and unexposed workers. In addition, a positive association between urine BPA and E2 was observed among exposed workers with borderline significance, while a statistically significant inverse association between urine BPA and FSH was observed among unexposed group. The results suggest that BPA exposure may lead to alterations in female reproductive hormone levels.

  11. Stress and Fatigue in Operators Under Radiofrequency Electromagnetic Radiation and Shift Work

    Directory of Open Access Journals (Sweden)

    Vangelova K.

    2014-12-01

    Full Text Available The aim was to study the effect of radiofrequency electromagnetic radiation (EMR on stress indices, health complaints and fatigue of operators working fast-rotating extended shifts. Working conditions, job content, job control, social support, health complaints and fatigue were followed in 220 operators, 110 exposed to EMR and 110 control operators, matched by age and sex. The EMR was measured and time-weighted average (TWA was calculated. The excretion rates of stress hormones cortisol, adrenaline and noradrenaline were followed during the extended shifts in 36 operators, working at different levels of exposure and 24-hour exposure was calculated. The exposed group pointed more problems with the working conditions, including EMR, noise, currents and risk of accidents, more health complaints and higher level of fatigue. The most common health complaints were mental and physical exhaustion after work, pains in the chest, musculoskeletal complaints, headache, and apathy. High level EMR exposure (TWAmean = 3.10 μW/cm2, TWAmax = 137.00 μW/cm2 significantly increased the 24-hour excretion of cortisol and noradrenaline, whereas the increase of adrenaline excretion did not reach significance, as well as hormone excretion rates under low level exposure (TWAmean = 1.89 μW/cm2, TWAmax = 5.24 μW/cm2. In conclusion, higher number of health complaints, higher stress hormone excretion rates and fatigue were found in operators under EMR.

  12. Assessment of bioavailable fraction of POPS in surface water bodies in Johannesburg City, South Africa, using passive samplers: an initial assessment.

    Science.gov (United States)

    Amdany, Robert; Chimuka, Luke; Cukrowska, Ewa; Kukučka, Petr; Kohoutek, Jiří; Tölgyessy, Peter; Vrana, Branislav

    2014-09-01

    In this study, the semipermeable membrane device (SPMD) passive samplers were used to determine freely dissolved concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in selected water bodies situated in and around Johannesburg City, South Africa. The devices were deployed for 14 days at each sampling site in spring and summer of 2011. Time weighted average (TWA) concentrations of the water-borne contaminants were calculated from the amounts of analytes accumulated in the passive samplers. In the area of interest, concentrations of analytes in water ranged from 33.5 to 126.8 ng l(-1) for PAHs, from 20.9 to 120.9 pg l(-1) for PCBs and from 0.2 to 36.9 ng l(-1) for OCPs. Chlorinated pesticides were mainly composed of hexachlorocyclohexanes (HCHs) (0.15-36.9 ng l(-1)) and dichlorodiphenyltrichloromethane (DDT) with its metabolites (0.03-0.55 ng l(-1)). By applying diagnostic ratios of certain PAHs, identification of possible sources of the contaminants in the various sampling sites was performed. These ratios were generally inclined towards pyrogenic sources of pollution by PAHs in all study sites except in the Centurion River (CR), Centurion Lake (CL) and Airport River (AUP) that indicated petrogenic origins. This study highlights further need to map up the temporal and spatial variations of these POPs using passive samplers.

  13. Exposures to jet fuel and benzene during aircraft fuel tank repair in the U.S. Air Force.

    Science.gov (United States)

    Carlton, G N; Smith, L B

    2000-06-01

    Jet fuel and benzene vapor exposures were measured during aircraft fuel tank entry and repair at twelve U.S. Air Force bases. Breathing zone samples were collected on the fuel workers who performed the repair. In addition, instantaneous samples were taken at various points during the procedures with SUMMA canisters and subsequent analysis by mass spectrometry. The highest eight-hour time-weighted average (TWA) fuel exposure found was 1304 mg/m3; the highest 15-minute short-term exposure was 10,295 mg/m3. The results indicate workers who repair fuel tanks containing explosion suppression foam have a significantly higher exposure to jet fuel as compared to workers who repair tanks without foam (p fuel, absorbed by the foam, to volatilize during the foam removal process. Fuel tanks that allow flow-through ventilation during repair resulted in lower exposures compared to those tanks that have only one access port and, as a result, cannot be ventilated efficiently. The instantaneous sampling results confirm that benzene exposures occur during fuel tank repair; levels up to 49.1 mg/m3 were found inside the tanks during the repairs. As with jet fuel, these elevated benzene concentrations were more likely to occur in foamed tanks. The high temperatures associated with fuel tank repair, along with the requirement to wear vapor-permeable cotton coveralls for fire reasons, could result in an increase in the benzene body burden of tank entrants.

  14. Associations between Bisphenol A Exposure and Reproductive Hormones among Female Workers.

    Science.gov (United States)

    Miao, Maohua; Yuan, Wei; Yang, Fen; Liang, Hong; Zhou, Zhijun; Li, Runsheng; Gao, Ersheng; Li, De-Kun

    2015-10-22

    The associations between Bisphenol-A (BPA) exposure and reproductive hormone levels among women are unclear. A cross-sectional study was conducted among female workers from BPA-exposed and unexposed factories in China. Women's blood samples were collected for assay of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17β-Estradiol (E2), prolactin (PRL), and progesterone (PROG). Their urine samples were collected for BPA measurement. In the exposed group, time weighted average exposure to BPA for an 8-h shift (TWA8), a measure incorporating historic exposure level, was generated based on personal air sampling. Multiple linear regression analyses were used to examine linear associations between urine BPA concentration and reproductive hormones after controlling for potential confounders. A total of 106 exposed and 250 unexposed female workers were included in this study. A significant positive association between increased urine BPA concentration and higher PRL and PROG levels were observed. Similar associations were observed after the analysis was carried out separately among the exposed and unexposed workers. In addition, a positive association between urine BPA and E2 was observed among exposed workers with borderline significance, while a statistically significant inverse association between urine BPA and FSH was observed among unexposed group. The results suggest that BPA exposure may lead to alterations in female reproductive hormone levels.

  15. Employment type, workplace interpersonal conflict, and insomnia: a cross-sectional study of 37,646 employees in Japan.

    Science.gov (United States)

    Sakurai, Kenji; Nakata, Aknori; Ikeda, Tomoko; Otsuka, Yasumasa; Kawahito, Junko

    2014-01-01

    This study explored whether workplace interpersonal conflict (WIC) is associated with insomnia, and whether the relationship between WIC and insomnia differs across different employment groups. A total of 37,646 Japanese full-time employees participated in a cross-sectional survey. Employment types included permanent employment and 2 forms of temporary employment: direct-hire and temporary work agent (TWA). Insomnia symptoms, including difficulty initiating sleep, difficulty maintaining sleep, and early morning awakening were measured. Insomnia was defined as having experienced 1 or more of these symptoms on ≥3 nights per week over the past 12 months. Results showed that WIC was significantly associated with an increased risk of insomnia (odds ratio OR = 1.63; 95% confidence interval CI = 1.55-1.71), controlling for confounders. However, the relationship between WIC and the risk of insomnia was significantly stronger for TWAs than for permanent employees (OR = 1.97; 95% CI = 1.13-3.45). A frequent exposure to WIC may increase the risk of insomnia, particularly for TWAs.

  16. Size characterization of airborne SiO2 nanoparticles with on-line and off-line measurement techniques: an interlaboratory comparison study

    Science.gov (United States)

    Motzkus, C.; Macé, T.; Gaie-Levrel, F.; Ducourtieux, S.; Delvallee, A.; Dirscherl, K.; Hodoroaba, V.-D.; Popov, I.; Popov, O.; Kuselman, I.; Takahata, K.; Ehara, K.; Ausset, P.; Maillé, M.; Michielsen, N.; Bondiguel, S.; Gensdarmes, F.; Morawska, L.; Johnson, G. R.; Faghihi, E. M.; Kim, C. S.; Kim, Y. H.; Chu, M. C.; Guardado, J. A.; Salas, A.; Capannelli, G.; Costa, C.; Bostrom, T.; Jämting, Å. K.; Lawn, M. A.; Adlem, L.; Vaslin-Reimann, S.

    2013-10-01

    Results of an interlaboratory comparison on size characterization of SiO2 airborne nanoparticles using on-line and off-line measurement techniques are discussed. This study was performed in the framework of Technical Working Area (TWA) 34—"Properties of Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS) in the project no. 3 "Techniques for characterizing size distribution of airborne nanoparticles". Two types of nano-aerosols, consisting of (1) one population of nanoparticles with a mean diameter between 30.3 and 39.0 nm and (2) two populations of non-agglomerated nanoparticles with mean diameters between, respectively, 36.2-46.6 nm and 80.2-89.8 nm, were generated for characterization measurements. Scanning mobility particle size spectrometers (SMPS) were used for on-line measurements of size distributions of the produced nano-aerosols. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were used as off-line measurement techniques for nanoparticles characterization. Samples were deposited on appropriate supports such as grids, filters, and mica plates by electrostatic precipitation and a filtration technique using SMPS controlled generation upstream. The results of the main size distribution parameters (mean and mode diameters), obtained from several laboratories, were compared based on metrological approaches including metrological traceability, calibration, and evaluation of the measurement uncertainty. Internationally harmonized measurement procedures for airborne SiO2 nanoparticles characterization are proposed.

  17. Size characterization of airborne SiO{sub 2} nanoparticles with on-line and off-line measurement techniques: an interlaboratory comparison study

    Energy Technology Data Exchange (ETDEWEB)

    Motzkus, C., E-mail: charles.motzkus@lne.fr; Mace, T.; Gaie-Levrel, F.; Ducourtieux, S.; Delvallee, A. [Laboratoire National de Metrologie et d' Essais (LNE) (France); Dirscherl, K. [Danish Fundamental Metrology (DFM) (Denmark); Hodoroaba, V.-D. [BAM Federal Institute for Materials Research and Testing (Germany); Popov, I. [The Hebrew University of Jerusalem, Unit for Nanocharacterization (Israel); Popov, O.; Kuselman, I. [National Physical Laboratory of Israel (INPL) (Israel); Takahata, K.; Ehara, K. [National Institute of Advanced Industrial Science and Technology (AIST), National Metrology Institute of Japan (NMIJ) (Japan); Ausset, P.; Maille, M. [Universite Paris-Est Creteil et Universite Paris-Diderot, Laboratoire Interuniversitaire des Systemes Atmospheriques (LISA), UMR CNRS 7583 (France); Michielsen, N.; Bondiguel, S.; Gensdarmes, F. [Institut de Radioprotection et de Surete Nucleaire (IRSN), PSN-RES, SCA, LPMA (France); Morawska, L.; Johnson, G. R.; Faghihi, E. M. [Queensland University of Technology (QUT), International Laboratory for Air Quality and Health (ILAQH) (Australia); and others

    2013-10-15

    Results of an interlaboratory comparison on size characterization of SiO{sub 2} airborne nanoparticles using on-line and off-line measurement techniques are discussed. This study was performed in the framework of Technical Working Area (TWA) 34-'Properties of Nanoparticle Populations' of the Versailles Project on Advanced Materials and Standards (VAMAS) in the project no. 3 'Techniques for characterizing size distribution of airborne nanoparticles'. Two types of nano-aerosols, consisting of (1) one population of nanoparticles with a mean diameter between 30.3 and 39.0 nm and (2) two populations of non-agglomerated nanoparticles with mean diameters between, respectively, 36.2-46.6 nm and 80.2-89.8 nm, were generated for characterization measurements. Scanning mobility particle size spectrometers (SMPS) were used for on-line measurements of size distributions of the produced nano-aerosols. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were used as off-line measurement techniques for nanoparticles characterization. Samples were deposited on appropriate supports such as grids, filters, and mica plates by electrostatic precipitation and a filtration technique using SMPS controlled generation upstream. The results of the main size distribution parameters (mean and mode diameters), obtained from several laboratories, were compared based on metrological approaches including metrological traceability, calibration, and evaluation of the measurement uncertainty. Internationally harmonized measurement procedures for airborne SiO{sub 2} nanoparticles characterization are proposed.

  18. An Integrated Approach to Assess Exposure and Health-Risk from Polycyclic Aromatic Hydrocarbons (PAHs in a Fastener Manufacturing Industry

    Directory of Open Access Journals (Sweden)

    Hsin-I Hsu

    2014-09-01

    Full Text Available An integrated approach was developed to assess exposure and health-risk from polycyclic aromatic hydrocarbons (PAHs contained in oil mists in a fastener manufacturing industry. One previously developed model and one new model were adopted for predicting oil mist exposure concentrations emitted from metal work fluid (MWF and PAHs contained in MWF by using the fastener production rate (Pr and cumulative fastener production rate (CPr as predictors, respectively. By applying the annual Pr and CPr records to the above two models, long-term workplace PAH exposure concentrations were predicted. In addition, true exposure data was also collected from the field. The predicted and measured concentrations respectively served as the prior and likelihood distributions in the Bayesian decision analysis (BDA, and the resultant posterior distributions were used to determine the long-term exposure and health-risks posed on workers. Results show that long term exposures to PAHs would result in a 3.1%, 96.7%, and 73.4% chance of exceeding the PEL-TWA (0.2 mg/m3, action level (0.1 mg/m3, and acceptable health risk (10−3, respectively. In conclusion, preventive measures should be taken immediately to reduce workers’ PAH exposures.

  19. Exposures to asbestos arising from bandsawing gasket material.

    Science.gov (United States)

    Fowler, D P

    2000-05-01

    A simulation of bandsawing sheet asbestos gasket material was performed as part of a retrospective exposure evaluation undertaken to assist in determining causation of a case of mesothelioma. The work was performed by bandsawing a chrysotile asbestos (80%)/neoprene gasket sheet with a conventional 16-inch woodworking bandsaw inside a chamber. Measurements of airborne asbestos were made using conventional area and personal sampling methods, with analysis of collected samples by transmission electron microscopy (TEM) and phase contrast microscopy (PCM). These were supplemented by qualitative scanning electron microscopy (SEM) examinations of some of the airborne particles collected on the filters. In contrast with findings from studies examining manual handling (installation and removal) of gaskets, airborne asbestos concentrations from this operation were found to be well above current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) (eight-hour time-weighted average [TWA]) and excursion limit (30-minute) standards. Although some "encapsulation" effect of the neoprene matrix was seen on the particles in the airborne dust, unencapsulated individual fiber bundles were also seen. Suggestions for the implications of the work are given. In summary, the airborne asbestos concentrations arising from this work were quite high, and point to the need for careful observation of common sense precautions when manipulation of asbestos-containing materials (even those believed to have limited emissions potential) may involved machining operations.

  20. A statistical evaluation of asbestos air concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Lange, J.H. [Envirosafe Training and Consultants, Pittsburgh, PA (United States)

    1999-07-01

    Both area and personal air samples collected during an asbestos abatement project were matched and statistically analysed. Among the many parameters studied were fibre concentrations and their variability. Mean values for area and personal samples were 0.005 and 0.024 f cm{sup -}-{sup 3} of air, respectively. Summary values for area and personal samples suggest that exposures are low with no single exposure value exceeding the current OSHA TWA value of 0.1 f cm{sup -3} of air. Within- and between-worker analysis suggests that these data are homogeneous. Comparison of within- and between-worker values suggests that the exposure source and variability for abatement are more related to the process than individual practices. This supports the importance of control measures for abatement. Study results also suggest that area and personal samples are not statistically related, that is, there is no association observed for these two sampling methods when data are analysed by correlation or regression analysis. Personal samples were statistically higher in concentration than area samples. Area sampling cannot be used as a surrogate exposure for asbestos abatement workers. (author)

  1. Passive Sampling and Analysis of Naphthalene in Internal Combustion Engine Exhaust with Retracted SPME Device and GC-MS

    Directory of Open Access Journals (Sweden)

    Nassiba Baimatova

    2017-07-01

    Full Text Available Exhaust gases from internal combustion engines are the main source of urban air pollution. Quantification of Polycyclic aromatic hydrocarbons (PAHs in the exhaust gases is needed for emissions monitoring, enforcement, development, and testing of control technologies. The objective was to develop quantification of gaseous naphthalene in diesel engine exhaust based on diffusion-controlled extraction onto a retracted solid-phase microextraction (SPME fiber coating and analysis on gas chromatography-mass spectrometry (GC-MS. Extraction of naphthalene with retracted fibers followed Fick’s law of diffusion. Extracted mass of naphthalene was proportional to Cg, t, Dg, T and inversely proportional to Z. Method detection limit (p = 0.95 was 11.5 ppb (0.06 mg·m−3 at t = 9 h, Z = 10 mm and T = 40 °C, respectively. It was found that the % mass extracted of naphthalene by SPME needle assembly depended on the type of fiber. Storage time at different temperatures did not affect analyte losses extracted by polydimethylsiloxane (PDMS 100 µm fiber. The developed method was tested on exhaust gases from idling pickup truck and tractor, and compared side-by-side with a direct injection of sampled exhaust gas method. Time-weighted average (TWA concentrations of naphthalene in exhaust gases from idling pickup truck and a tractor ranged from 0.08 to 0.3 mg·m−3 (15.3–53.7 ppb.

  2. Styrene vapor control systems in FRP yacht plants.

    Science.gov (United States)

    Todd, W F

    1985-01-01

    The production of large (greater than 25-ft) fiber-reinforced plastic (FRP) yachts has presented problems of styrene exposure in excess of the Occupational Safety and Health Administration permissible exposure level (OSHA PEL) of 100 ppm. Also, the National Institute for Occupational Safety and Health (NIOSH) is currently recommending a 10-hour workshift, 40-hour workweek time weighted average (TWA) of 50 ppm for styrene. Meeting this challenge will require a system of engineering, work practice, personal protective equipment, and monitoring control measures. NIOSH has performed a study of the engineering controls in three FRP yacht plants. Work practices and the use of personal protective equipment (PPE) were also considered in the evaluation. The three systems evaluated included a dilution system, a local ventilation system, and a push-pull ventilation system. The cost of constructing and operating these systems was not evaluated in this study. Study results indicated that each type of ventilation system can meet the present PEL of 100 ppm styrene; however, it is not certain that these systems can meet a lower PEL of 50 ppm styrene.

  3. Lithium in Drinking Water and Incidence of Suicide

    DEFF Research Database (Denmark)

    Knudsen, Nikoline N.; Schullehner, Jörg; Hansen, Birgitte

    2017-01-01

    Suicide is a major public health concern. High-dose lithium is used to stabilize mood and prevent suicide in patients with affective disorders. Lithium occurs naturally in drinking water worldwide in much lower doses, but with large geographical variation. Several studies conducted at an aggregate...... level have suggested an association between lithium in drinking water and a reduced risk of suicide; however, a causal relation is uncertain. Individual-level register-based data on the entire Danish adult population (3.7 million individuals) from 1991 to 2012 were linked with a moving five-year time......-weighted average (TWA) lithium exposure level from drinking water hypothesizing an inverse relationship. The mean lithium level was 11.6 μg/L ranging from 0.6 to 30.7 μg/L. The suicide rate decreased from 29.7 per 100,000 person-years at risk in 1991 to 18.4 per 100,000 person-years in 2012. We found...

  4. Measurement of residual stress in textured Al alloy by neutron diffraction method

    International Nuclear Information System (INIS)

    Okido, S.; Hayashi, M.; Tanaka, K.; Akiniwa, Y.; Minakawa, N.; Morii, Y.

    1999-01-01

    Residual stress generated in a shrunken aluminum alloy specimen, which was prepared for the round robin test conducted by VAMAS (Versailles Project on Advanced Materials and Standards) TWA-20 organized for the purpose of standardizing residual stress measurement methods, was evaluated by a neutron diffraction method. The main purpose of the round robin test was to assess the reproducibility of data obtained with the measurement facilities of the participants. The general standard of the Residual Stress Analyzer (RESA) constructed in the Japan Atomic Energy Research Institute was verified from the measured residual strains, which were equivalent to the values calculated by FEM and values measured by the research facilities in North America. Residual stress was calculated from residual strain in three perpendicular directions. The diffraction intensities were dependent on measurement directions since the prepared specimen possessed texture. Diffraction profiles in directions having a weak diffraction intensity caused an inaccurate evaluation of the residual stress. To solve this problem, a new method for evaluating residual stress with respect to diffraction plane dependency of the elastic constant was applied. The diffraction plane giving the highest intensity among 110, 200, and 220 diffraction was used to evaluate the residual strain in each of three directions. The residual strain obtained on the used diffraction plane was converted to the equivalent strain for the defined diffraction plane using the ratio of elastic constants of these two planes. The developed evaluation method achieved highly accurate measurement and remarkable efficiency in the measurement process. (author)

  5. Passive sampling of bioavailable organic chemicals in Perry County, Missouri cave streams.

    Science.gov (United States)

    Fox, J Tyler; Adams, Ginny; Sharum, Martin; Steelman, Karen L

    2010-12-01

    Two types of passive samplers--semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCIS)--were deployed in spring 2008 to assess bioavailable concentrations of aquatic contaminants in five cave streams and resurgences in Perry County, Missouri. Study sites represent areas of high cave biodiversity and the only known habitat for grotto sculpin (Cottus carolinae). Time-weighted average (TWA) water concentrations were calculated for 20 compounds (n = 9 SPMDs; n = 11 POCIS) originating primarily from agricultural sources, including two organochlorine insecticides, dieldrin and heptachlor epoxide, which were found at levels exceeding U.S. EPA criteria for the protection of aquatic life. GIS data were used to quantify and map sinkhole distribution and density within the study area. Infiltration of storm runoff and its influence on contaminant transport were also evaluated using land cover and hydrological data. This work provides evidence of cave stream contamination by a mix of organic chemicals and demonstrates the applicability of passive samplers for monitoring water quality in dynamic karst environments where rapid transmission of storm runoff makes instantaneous water sampling difficult.

  6. Water balance model and eucalyptus growth simulation in the rio doce basin, Brazil - doi: 10.4025/actasciagron.v35i4.16955

    Directory of Open Access Journals (Sweden)

    Welliam Chaves Monteiro Silva

    2013-05-01

    Full Text Available Although the 3-PG model is widely used for forest productivity calculations, there are processes that do not present appropriate physical treatment. The aim of this study was to generate a tool to improve the water balance calculation in the model to enhance the energy balance and transpiration process. The calculation of transpiration was modified to account for variations in solar radiation with the inclination and azimuth of the terrain; the vapor pressure deficit was changed based on the relative humidity and air temperature; and the stomatal conductance varied according to solar radiation, vapor pressure deficit and air temperature. The water storage in the soil varied with the depth of the root system and the total water availability (TWA in the soil. The assessment was also changed from a monthly to an hourly basis. The study was conducted in areas surrounding Cenibra, and the data were collected from the Rio Doce river basin, in the Brazilian state of Minas Gerais. Taken together, these modifications improved growth - modeling processes and enhanced the capacity of this analytical tool to differentiate intra - region productivity.

  7. Distribution of exposure concentrations and doses for constituents of environmental tobacco smoke

    Energy Technology Data Exchange (ETDEWEB)

    LaKind, J.S. [LaKind Associates (United States); Ginevan, M.E. [M.E. Ginevan and Associates (United States); Naiman, D.Q. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Mathematical Sciences; James, A.C. [A.C. James and Associates (United States); Jenkins, R.A. [Oak Ridge National Lab., TN (United States); Dourson, M.L.; Felter, S.P. [TERA (United States); Graves, C.G.; Tardiff, R.G. [Sapphire Group, Inc., Bethesda, MD (United States)

    1999-06-01

    The ultimate goal of the research reported in this series of three articles is to derive distributions of doses of selected environmental tobacco smoke (ETS)-related chemicals for nonsmoking workers. This analysis uses data from the 16-City Study collected with personal monitors over the course of one workday in workplaces where smoking occurred. In this article, the authors describe distributions of ETS chemical concentrations and the characteristics of those distributions for the workplace exposure. Next, they present population parameters relevant for estimating dose distributions and the methods used for estimating those dose distributions. Finally, they derive distributions of doses of selected ETS-related constituents obtained in the workplace for people in smoking work environments. Estimating dose distributions provided information beyond the usual point estimate of dose and showed that the preponderance of individuals exposed to ETS in the workplace were exposed at the low end of the dose distribution curve. The results of this analysis include estimations of hourly maxima and time-weighted average (TWA) doses of nicotine from workplace exposures to ETS and doses derived from modeled lung burdens of ultraviolet-absorbing particulate matter (UVPM) and solanesol resulting from workplace exposures to ETS (extrapolated from 1 day to 1 year).

  8. Breakthrough indicator for aromatic VOCs using needle trap samplers for activated carbon adsorbent.

    Science.gov (United States)

    Cheng, Wen-Hsi; Jiang, Jia-Rong; Huang, Yi-Ning; Huang, Shiun-Chian; Yu, Yan-Pin

    2012-08-01

    Internal circulation cabinets equipped with granular activated carbon (GAC) for adsorbing volatile organic compounds (VOCs) are widely used to store bottles containing organic solvents in universities, colleges, and hospital laboratories throughout Taiwan. This work evaluates the VOC adsorption capacities of GAC using various adsorption times for gas stream mixtures of 100 ppm toluene and 100 ppm o-xylene. Additionally, needle trap sampling (NTS) technology was used to indicate the time for renewing the GAC to avoid VOC breakthrough from adsorbents. Experimental results demonstrate that the proposed models can linearly express toluene and o-xylene adsorption capacities as the natural logarithm of adsorption time (ln(t)) and can accurately simulate the equilibrium adsorption capacities (Qe, g VOCs/g GAC) for gaseous toluene and o-xylene. The NTS, packed with 60-80 mesh divinylbenzene (DVB) particles, was compared in terms of extraction efficiency by simultaneously using the 75-microm Carboxen/polydimethylsiloxane-solid-phase microextraction (Carboxen/PDMS-SPME) fiber for time-weighted average (TWA) sampling, and experimental results indicated that the packed DVB-NTS achieved higher toluene extraction rates. Additionally, the NTS installed in the outlet air stream for adsorbing toluene and o-xylene exhausted through GAC accurately indicated toluene and o-xylene breakthrough times of 4700-5000 min. The GAC-NTS operational instructions to indicate the replacing time of adsorbent in the internal circulation cabinets are also included in this paper.

  9. Elevated urinary levels of kidney injury molecule-1 among Chinese factory workers exposed to trichloroethylene

    Science.gov (United States)

    Vermeulen, Roel; Huang, Hanlin; Rothman, Nathaniel; Lan, Qing

    2012-01-01

    Epidemiological studies suggest that trichloroethylene (TCE) exposure may be associated with renal cancer. The biological mechanisms involved are not exactly known although nephrotoxicity is believed to play a role. Studies on TCE nephrotoxicity among humans, however, have been largely inconsistent. We studied kidney toxicity in Chinese factory workers exposed to TCE using novel sensitive nephrotoxicity markers. Eighty healthy workers exposed to TCE and 45 comparable unexposed controls were included in the present analyses. Personal TCE exposure measurements were taken over a 2-week period before urine collection. Ninety-six percent of workers were exposed to TCE below the current US Occupational Safety and Health Administration permissible exposure limit (100 ppm 8h TWA), with a mean (SD) of 22.2 (35.9) ppm. Kidney injury molecule-1 (KIM-1) and Pi-glutathione S transferase (GST) alpha were elevated among the exposed subjects as compared with the unexposed controls with a strong exposure-response association between individual estimates of TCE exposure and KIM-1 (P < 0.0001). This is the first report to use a set of sensitive nephrotoxicity markers to study the possible effects of TCE on the kidneys. The findings suggest that at relatively low occupational exposure levels a toxic effect on the kidneys can be observed. This finding supports the biological plausibility of linking TCE exposure and renal cancer. Abbreviations:GSTglutathione-S-transferaseKIM-1kidney injury molecule-1NAGN-acetyl-beta-(d)-glucosaminidaseOVMorganic vapour monitoringTCEtrichloroethyleneVEGFvascular endothelial growth factor. PMID:22665366

  10. Fugitive emissions from nanopowder manufacturing

    International Nuclear Information System (INIS)

    Trompetter, W. J.; Ancelet, T.; Davy, P. K.; Kennedy, J.

    2016-01-01

    In response to health and safety questions and concerns regarding particulate matter emissions from equipment used for synthesizing NiFe and TiO 2 nanopowders, a study was undertaken to assess their impact on the air quality inside and outside a laboratory where the manufacturing equipment is operated. Elemental concentrations determined by ion beam analysis (IBA) of air particulate matter (PM) samples collected hourly with a Streaker TM sampler were used to identify possible sources and estimate contributions from nanopowder production and other sources. The fugitive nanopowder emissions were the highest at the indoor sampling location when powders were being manufactured. Average fugitive emissions of 210 ng m −3 (1-h average) (maximum 2163 ng m −3 1-h average) represented 2 % (maximum 20 %) of the average PM collected (9359 ng m −3 1-h average). The measured NiFe alloy or TiO 2 PM concentrations were much smaller than the 8-h time-weighted average (TWA) workplace exposure standards (WES) for these materials (≥1,000,000 ng m −3 ). Most PM was found to be from infiltrated outdoor ambient sources. This suggests that nanopowder production in the laboratory is not likely to have adverse health effects on individuals using the equipment, although further improvements can be made to further limit exposure.Graphical abstract

  11. Topological and categorical properties of binary trees

    Directory of Open Access Journals (Sweden)

    H. Pajoohesh

    2008-04-01

    Full Text Available Binary trees are very useful tools in computer science for estimating the running time of so-called comparison based algorithms, algorithms in which every action is ultimately based on a prior comparison between two elements. For two given algorithms A and B where the decision tree of A is more balanced than that of B, it is known that the average and worst case times of A will be better than those of B, i.e., ₸A(n ≤₸B(n and TWA (n≤TWB (n. Thus the most balanced and the most imbalanced binary trees play a main role. Here we consider them as semilattices and characterize the most balanced and the most imbalanced binary trees by topological and categorical properties. Also we define the composition of binary trees as a commutative binary operation, *, such that for binary trees A and B, A * B is the binary tree obtained by attaching a copy of B to any leaf of A. We show that (T,* is a commutative po-monoid and investigate its properties.

  12. A practical approach to estimate emission rates of indoor air pollutants due to the use of personal combustible products based on small-chamber studies.

    Science.gov (United States)

    Szulejko, Jan E; Kim, Ki-Hyun

    2016-02-01

    As emission rates of airborne pollutants are commonly measured from combusting substances placed inside small chambers, those values need to be re-evaluated for the possible significance under practical conditions. Here, a simple numerical procedure is investigated to extrapolate the chamber-based emission rates of formaldehyde that can be released from various combustible sources including e-cigarettes, conventional cigarettes, or scented candles to their concentration levels in a small room with relatively poor ventilation. This simple procedure relies on a mass balance approach by considering the masses of pollutants emitted from source and lost through ventilation under the assumption that mixing occurs instantaneously in the room without chemical reactions or surface sorption. The results of our study provide valuable insights into re-evaluation procedure of chamber data to allow comparison between extrapolated and recommended values to judge the safe use of various combustible products in confined spaces. If two scented candles with a formaldehyde emission rate of 310 µg h(-1) each were lit for 4 h in a small 20 m(3) room with an air change rate of 0.5 h(-1), then the 4-h (candle lit) and 8-h (up to 8 h after candle lighting) TWA [FA] were determined to be 28.5 and 23.5 ppb, respectively. This is clearly above the 8-h NIOSH recommended exposure limit (REL) time weighted average of 16 ppb. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Evaluation of occupational exposure to toxic metals released in the process of aluminum welding.

    Science.gov (United States)

    Matczak, Wanda; Gromiec, Jan

    2002-04-01

    The objective of this study was to evaluate occupational exposure to welding fumes and its elements on aluminum welders in Polish industry. The study included 52 MIG/Al fume samples and 18 TIG/Al samples in 3 plants. Air samples were collected in the breathing zone of welders (total and respirable dust). Dust concentration was determined gravimetrically, and the elements in the collected dust were determined by AAS. Mean time-weighted average (TWA) concentrations of the welding dusts/fumes and their components in the breathing zone obtained for different welding processes were, in mg/m3: MIG/Al fumes mean 6.0 (0.8-17.8), Al 2.1 (0.1-7.7), Mg 0.2 (TIG/Al fumes 0.7 (0.3-1.4), Al 0.17 (0.07-0.50). A correlation has been found between the concentration of the main components and the fume/dust concentrations in MIG/Al and TIG/Al fumes. Mean percentages of the individual components in MIG/Al fumes/dusts were Al: 30 (9-56) percent; Mg: 3 (1-5.6) percent; Mn: 0.2 (0.1-0.3) percent; Cu: 0.2 (welding methods, the nature of welding-related operations, and work environment conditions.

  14. Thermal diffusivity measurement of erythritol and numerical analysis of heat storage performance on a fin-type heat exchanger

    International Nuclear Information System (INIS)

    Zamengo, Massimiliano; Funada, Tomohiro; Morikawa, Junko

    2017-01-01

    Highlights: • Thermal diffusivity of Erythritol was measured by temperature wave method. • Thermal diffusivity was measured in function of temperature and during phase change. • Database of temperature-dependent thermal properties is used for numerical analysis. • Heat transfer and heat storage were analyzed in a fin-type heat exchanger. • Use of temperature-dependent properties in calculations lead to longer melting time. - Abstract: Temperature dependency of thermal diffusivity of erythritol was measured by temperature wave analysis (TWA) method. This modulating technique allowed measuring thermal diffusivity continuously, even during the phase transition solid-liquid. Together with specific heat capacity and specific enthalpy measured by differential scanning calorimetry, the values of measured properties were utilized in a bi-dimensional numerical model for analysis of heat transfer and heat storage performance. The geometry of the model is representative of a cross section of a fin-type heat exchanger, in which erythritol is filling the interspaces between fins. Time-dependent temperature change and heat storage performance were analyzed by considering the variation of thermophysical properties as a function of temperature. The numerical method can be utilized for a fast parametric analysis of heat transfer and heat storage performance into heat storage systems of phase-change materials and composites.

  15. Beyond Conflict and Spoilt Identities: How Rwandan Leaders Justify a Single Recategorization Model for Post-Conflict Reconciliation

    Directory of Open Access Journals (Sweden)

    Sigrun Marie Moss

    2014-08-01

    Full Text Available Since 1994, the Rwandan government has attempted to remove the division of the population into the ‘ethnic’ identities Hutu, Tutsi and Twa and instead make the shared Rwandan identity salient. This paper explores how leaders justify the single recategorization model, based on nine in-depth semi-structured interviews with Rwandan national leaders (politicians and bureaucrats tasked with leading unity implementation conducted in Rwanda over three months in 2011/2012. Thematic analysis revealed this was done through a meta-narrative focusing on the shared Rwandan identity. Three frames were found in use to “sell” this narrative where ethnic identities are presented as a an alien construction; b which was used to the disadvantage of the people; and c non-essential social constructs. The material demonstrates the identity entrepreneurship behind the single recategorization approach: the definition of the category boundaries, the category content, and the strategies for controlling and overcoming alternative narratives. Rwandan identity is presented as essential and legitimate, and as offering a potential way for people to escape spoilt subordinate identities. The interviewed leaders insist Rwandans are all one, and that the single recategorization is the right path for Rwanda, but this approach has been criticised for increasing rather than decreasing intergroup conflict due to social identity threat. The Rwandan case offers a rare opportunity to explore leaders’ own narratives and framing of these ‘ethnic’ identities to justify the single recategorization approach.

  16. [Effects of 1-bromopropane on neurological and hematological changes of female exposed workers].

    Science.gov (United States)

    Li, Wei-Hua; Zhou, Zhi-Jun; Wang, Qiang-Yi; Ichihara, Gaku; Takeuchi, Yasuhiro; Ding, Xun-Cheng

    2010-05-01

    To investigate the health effects of 1-bromopropane (1-BP) on female exposed workers. Four 1-BP manufacturing plants were investigated. Workers were interviewed with questionnaire and examined with neurobehavioral core test battery, nerve conduction velocity tests of nervus tibialis and nervus suralis, vibration sensation test, hematological and biochemical tests. Ambient 1-BP concentration was measured with detection tube, and time-weighed average levels of individual workers were estimated with passive samplers. 1-BP concentration in the plants ranged from 0 to 402.40 mg/m3 (Geomean 32.19 mg/m3). Time-weighted average exposure levels (TWA-8 h) ranged from 0.35 to 535.19 mg/m3 (Geomean 14.08 mg/m3). Compared with the control group, 1-BP exposed workers showed reduced motor nerve conduction velocity [(44.8 +/- 8.7) m/s] and sensory nerve conduction velocity [(45.5 +/- 4.9) m/s], prolonged distal latency [(7.5 +/- 2.1) ms], reduced toe vibration perception, and altered neurobehavior parameters(POMS vigor, tension, anxiety, confusion) significantly (P system, and lead to abnormal hematological and biomedical indicators.

  17. Pesticides from wastewater treatment plant effluents affect invertebrate communities.

    Science.gov (United States)

    Münze, Ronald; Hannemann, Christin; Orlinskiy, Polina; Gunold, Roman; Paschke, Albrecht; Foit, Kaarina; Becker, Jeremias; Kaske, Oliver; Paulsson, Elin; Peterson, Märit; Jernstedt, Henrik; Kreuger, Jenny; Schüürmann, Gerrit; Liess, Matthias

    2017-12-01

    We quantified pesticide contamination and its ecological impact up- and downstream of seven wastewater treatment plants (WWTPs) in rural and suburban areas of central Germany. During two sampling campaigns, time-weighted average pesticide concentrations (c TWA ) were obtained using Chemcatcher® passive samplers; pesticide peak concentrations were quantified with event-driven samplers. At downstream sites, receiving waters were additionally grab sampled for five selected pharmaceuticals. Ecological effects on macroinvertebrate structure and ecosystem function were assessed using the biological indicator system SPEAR pesticides (SPEcies At Risk) and leaf litter breakdown rates, respectively. WWTP effluents substantially increased insecticide and fungicide concentrations in receiving waters; in many cases, treated wastewater was the exclusive source for the neonicotinoid insecticides acetamiprid and imidacloprid in the investigated streams. During the ten weeks of the investigation, five out of the seven WWTPs increased in-stream pesticide toxicity by a factor of three. As a consequence, at downstream sites, SPEAR values and leaf litter degradation rates were reduced by 40% and 53%, respectively. The reduced leaf litter breakdown was related to changes in the macroinvertebrate communities described by SPEAR pesticides and not to altered microbial activity. Neonicotinoids showed the highest ecological relevance for the composition of invertebrate communities, occasionally exceeding the Regulatory Acceptable Concentrations (RACs). In general, considerable ecological effects of insecticides were observed above and below regulatory thresholds. Fungicides, herbicides and pharmaceuticals contributed only marginally to acute toxicity. We conclude that pesticide retention of WWTPs needs to be improved. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Size characterization of airborne SiO2 nanoparticles with on-line and off-line measurement techniques: an interlaboratory comparison study

    International Nuclear Information System (INIS)

    Motzkus, C.; Macé, T.; Gaie-Levrel, F.; Ducourtieux, S.; Delvallee, A.; Dirscherl, K.; Hodoroaba, V.-D.; Popov, I.; Popov, O.; Kuselman, I.; Takahata, K.; Ehara, K.; Ausset, P.; Maillé, M.; Michielsen, N.; Bondiguel, S.; Gensdarmes, F.; Morawska, L.; Johnson, G. R.; Faghihi, E. M.

    2013-01-01

    Results of an interlaboratory comparison on size characterization of SiO 2 airborne nanoparticles using on-line and off-line measurement techniques are discussed. This study was performed in the framework of Technical Working Area (TWA) 34—“Properties of Nanoparticle Populations” of the Versailles Project on Advanced Materials and Standards (VAMAS) in the project no. 3 “Techniques for characterizing size distribution of airborne nanoparticles”. Two types of nano-aerosols, consisting of (1) one population of nanoparticles with a mean diameter between 30.3 and 39.0 nm and (2) two populations of non-agglomerated nanoparticles with mean diameters between, respectively, 36.2–46.6 nm and 80.2–89.8 nm, were generated for characterization measurements. Scanning mobility particle size spectrometers (SMPS) were used for on-line measurements of size distributions of the produced nano-aerosols. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were used as off-line measurement techniques for nanoparticles characterization. Samples were deposited on appropriate supports such as grids, filters, and mica plates by electrostatic precipitation and a filtration technique using SMPS controlled generation upstream. The results of the main size distribution parameters (mean and mode diameters), obtained from several laboratories, were compared based on metrological approaches including metrological traceability, calibration, and evaluation of the measurement uncertainty. Internationally harmonized measurement procedures for airborne SiO 2 nanoparticles characterization are proposed

  19. A reconfigurable image tube using an external electronic image readout

    Science.gov (United States)

    Lapington, J. S.; Howorth, J. R.; Milnes, J. S.

    2005-08-01

    We have designed and built a sealed tube microchannel plate (MCP) intensifier for optical/NUV photon counting applications suitable for 18, 25 and 40 mm diameter formats. The intensifier uses an electronic image readout to provide direct conversion of event position into electronic signals, without the drawbacks associated with phosphor screens and subsequent optical detection. The Image Charge technique is used to remove the readout from the intensifier vacuum enclosure, obviating the requirement for additional electrical vacuum feedthroughs and for the readout pattern to be UHV compatible. The charge signal from an MCP intensifier is capacitively coupled via a thin dielectric vacuum window to the electronic image readout, which is external to the sealed intensifier tube. The readout pattern is a separate item held in proximity to the dielectric window and can be easily detached, making the system easily reconfigurable. Since the readout pattern detects induced charge and is external to the tube, it can be constructed as a multilayer, eliminating the requirement for narrow insulator gaps and allowing it to be constructed using standard PCB manufacturing tolerances. We describe two readout patterns, the tetra wedge anode (TWA), an optimized 4 electrode device similar to the wedge and strip anode (WSA) but with a factor 2 improvement in resolution, and an 8 channel high speed 50 ohm device, both manufactured as multilayer PCBs. We present results of the detector imaging performance, image resolution, linearity and stability, and discuss the development of an integrated readout and electronics device based on these designs.

  20. Diversity of cultivable bacteria involved in the formation of macroscopic microbial colonies (Cave silver on the walls of a cave in Slovenia

    Directory of Open Access Journals (Sweden)

    Blagajana Herzog Velikonja

    2014-01-01

    Full Text Available Karstic caves often support white, yellow, grey or pink microbial colonies that are termed ‘cave silver’ by speleologists. Using various sample pre-treatments and culture media, a wide variety of bacteria associated with these colonies were recovered from a cave in Slovenia, Pajsarjeva jama. Decreasing the inoculum size resulted in significant increases in viable counts, while pre-treatments had the opposite effect with the exception of microwave irradiation. While all growth media yielded viable counts, the maximal counts were observed on a low-nutrient TWA medium. Based on the 16S rRNA gene sequence of OTU representatives, the majority of the 80 isolates examined belonged to Streptomyces (25%, Micrococcus (16% and Rhodococcus (10% Other abundant groups were Pseudomonas (9%, Agrobacterium (8%, Lysobacter (6% and Paenibacillus (5%, while members of genera Microbacterium, Agrococcus, Arthrobacter, Bacillus, Kocuria, Oerskovia, Sphingomonas, Aerococcus, and Bosea represented a minor portion of cultivable diversity encountered. Members of Streptomyces and Agrobacterium were common to all samples. Although these microorganisms readily form colonies under laboratory conditions, they were unrelated to abundant environmental phylotypes recovered from same samples in a previous study. However, the comparative 16S rRNA analysis showed that microorganisms highly related to the ones obtained in this study were cultivated from other subterranean environments indicating that they might represent true microbial cave dwellers.

  1. Experimental measurements of Helicon wave coupling in KSTAR plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. J.; Wi, H. H.; Wang, S. J.; Park, S. Y.; Jeong, J. H.; Han, J. W.; Kwak, J. G.; Oh, Y. K. [National Fusion Research Institute, Daejeon (Korea, Republic of); Chun, M. H.; Yu, I. H. [Pohang Accelerator Laboratory, Pohang (Korea, Republic of)

    2016-05-15

    KSTAR tokamak can be a good platform to test this current drive concept because it has adequate machine parameters. Furthermore, KSTAR will have high electron beta plasmas in near future with additional ECH power. In 2015 KSTAR experiments, low-power traveling wave antenna has been designed, fabricated and installed for helicon wave coupling tests in KSTAT plasmas. In 2016 KSTAR campaign, 200 kW klystron power will be combined using three coaxial hybrid couplers and three dummy loads. High power RF will be fed into the traveling wave antenna with two coaxial feeders through two dual disk windows and 6 inch coaxial transmission line system. Current status and plan for high power helicon wave current drive system in KSTAR will be presented. Mock-up TWA antenna installed at the KSTAR reveals high couplings in both L- and H-mode plasmas. The coupling can be easily controlled by radial outer gap without degradation of plasma confinement or local gas puffing with slight decrease of plasma confinement.

  2. The Curious Case of PDS 11: A Nearby, >10 Myr Old, Classical T Tauri Binary System

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, Blesson; Manoj, P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Colaba, Mumbai 400005 (India); Bhatt, B. C.; Sahu, D. K.; Muneer, S. [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Maheswar, G., E-mail: blesson.mathew@tifr.res.in [Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital 263002 (India)

    2017-05-01

    We present results of our study of the PDS 11 binary system, which belongs to a rare class of isolated, high Galactic latitude T Tauri stars. Our spectroscopic analysis reveals that PDS 11 is an M2–M2 binary system with both components showing similar H α emission strengths. Both the components appear to be accreting and are classical T Tauri stars. The lithium doublet Li i  λ 6708, a signature of youth, is present in the spectrum of PDS 11A, but not in PDS 11B. From the application of lithium depletion boundary age-dating method and a comparison with the Li i  λ 6708 equivalent width distribution of moving groups, we estimated an age of 10–15 Myr for PDS 11A. Comparison with pre-main sequence evolutionary models indicates that PDS 11A is a 0.4 M {sub ⊙} T Tauri star at a distance of 114–131 pc. PDS 11 system does not appear to be associated with any known star-forming regions or moving groups. PDS 11 is a new addition, after TWA 30 and LDS 5606, to the interesting class of old, dusty, wide binary classical T Tauri systems in which both components are actively accreting.

  3. Fugitive emissions from nanopowder manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Trompetter, W. J., E-mail: b.trompetter@gns.cri.nz; Ancelet, T.; Davy, P. K.; Kennedy, J. [GNS Science (New Zealand)

    2016-07-15

    In response to health and safety questions and concerns regarding particulate matter emissions from equipment used for synthesizing NiFe and TiO{sub 2} nanopowders, a study was undertaken to assess their impact on the air quality inside and outside a laboratory where the manufacturing equipment is operated. Elemental concentrations determined by ion beam analysis (IBA) of air particulate matter (PM) samples collected hourly with a Streaker{sup TM} sampler were used to identify possible sources and estimate contributions from nanopowder production and other sources. The fugitive nanopowder emissions were the highest at the indoor sampling location when powders were being manufactured. Average fugitive emissions of 210 ng m{sup −3} (1-h average) (maximum 2163 ng m{sup −3} 1-h average) represented 2 % (maximum 20 %) of the average PM collected (9359 ng m{sup −3} 1-h average). The measured NiFe alloy or TiO{sub 2} PM concentrations were much smaller than the 8-h time-weighted average (TWA) workplace exposure standards (WES) for these materials (≥1,000,000 ng m{sup −3}). Most PM was found to be from infiltrated outdoor ambient sources. This suggests that nanopowder production in the laboratory is not likely to have adverse health effects on individuals using the equipment, although further improvements can be made to further limit exposure.Graphical abstract.

  4. Flight service evaluation of kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft: Flight service report

    Science.gov (United States)

    Stone, R. H.

    1981-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after 7 years service. There are six Kevlar-49 panels on each aircraft: a left hand and right hand set of a wing-body sandwich fairing; a slid laminate under-wing fillet panel; and a 422 K service aft engine fairing. The three L-1011s include one each in service with Eastern, Air Canada, and TWA. The fairings have accumulated a total of 52,500 hours, with one ship set having 17.700 hours service. The inspections were conducted at the airlines' major maintenance bases with the participation of Lockheed Engineering. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems or any condition requiring corrective action. The only defects noted were minor impact damage and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

  5. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    Science.gov (United States)

    Stone, R. H.

    1984-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after 10 years of service. There are six Kevlar-49 panels on each aircraft: a left-hand and right-hand set of a wing-body sandwich fairing; a solid laminate under-wing fillet panel; and a 422 K (300 F) service aft engine fairing. The three L-1011s include one each in service with Eastern, Air Canada, and TWA. The fairings have accumulated a total of 79,568 hours, with one ship set having nearly 28,000 hours service. The inspections were conducted at the airlines' major maintenance bases with the participation of Lockheed Engineering. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, a few minor disbonds and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings. The service history obtained in this program indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

  6. A statistical evaluation of asbestos air concentrations

    International Nuclear Information System (INIS)

    Lange, J.H.

    1999-01-01

    Both area and personal air samples collected during an asbestos abatement project were matched and statistically analysed. Among the many parameters studied were fibre concentrations and their variability. Mean values for area and personal samples were 0.005 and 0.024 f cm - - 3 of air, respectively. Summary values for area and personal samples suggest that exposures are low with no single exposure value exceeding the current OSHA TWA value of 0.1 f cm -3 of air. Within- and between-worker analysis suggests that these data are homogeneous. Comparison of within- and between-worker values suggests that the exposure source and variability for abatement are more related to the process than individual practices. This supports the importance of control measures for abatement. Study results also suggest that area and personal samples are not statistically related, that is, there is no association observed for these two sampling methods when data are analysed by correlation or regression analysis. Personal samples were statistically higher in concentration than area samples. Area sampling cannot be used as a surrogate exposure for asbestos abatement workers. (author)

  7. Modeled occupational exposures to gas-phase medical laser-generated air contaminants.

    Science.gov (United States)

    Lippert, Julia F; Lacey, Steven E; Jones, Rachael M

    2014-01-01

    Exposure monitoring data indicate the potential for substantive exposure to laser-generated air contaminants (LGAC); however the diversity of medical lasers and their applications limit generalization from direct workplace monitoring. Emission rates of seven previously reported gas-phase constituents of medical laser-generated air contaminants (LGAC) were determined experimentally and used in a semi-empirical two-zone model to estimate a range of plausible occupational exposures to health care staff. Single-source emission rates were generated in an emission chamber as a one-compartment mass balance model at steady-state. Clinical facility parameters such as room size and ventilation rate were based on standard ventilation and environmental conditions required for a laser surgical facility in compliance with regulatory agencies. All input variables in the model including point source emission rates were varied over an appropriate distribution in a Monte Carlo simulation to generate a range of time-weighted average (TWA) concentrations in the near and far field zones of the room in a conservative approach inclusive of all contributing factors to inform future predictive models. The concentrations were assessed for risk and the highest values were shown to be at least three orders of magnitude lower than the relevant occupational exposure limits (OELs). Estimated values do not appear to present a significant exposure hazard within the conditions of our emission rate estimates.

  8. Assessment of airborne asbestos exposure during the servicing and handling of automobile asbestos-containing gaskets.

    Science.gov (United States)

    Blake, Charles L; Dotson, G Scott; Harbison, Raymond D

    2006-07-01

    Five test sessions were conducted to assess asbestos exposure during the removal or installation of asbestos-containing gaskets on vehicles. All testing took place within an operative automotive repair facility involving passenger cars and a pickup truck ranging in vintage from late 1960s through 1970s. A professional mechanic performed all shop work including engine disassembly and reassembly, gasket manipulation and parts cleaning. Bulk sample analysis of removed gaskets through polarized light microscopy (PLM) revealed asbestos fiber concentrations ranging between 0 and 75%. Personal and area air samples were collected and analyzed using National Institute of Occupational Safety Health (NIOSH) methods 7400 [phase contrast microscopy (PCM)] and 7402 [transmission electron microscopy (TEM)]. Among all air samples collected, approximately 21% (n = 11) contained chrysotile fibers. The mean PCM and phase contrast microscopy equivalent (PCME) 8-h time weighted average (TWA) concentrations for these samples were 0.0031 fibers/cubic centimeters (f/cc) and 0.0017 f/cc, respectively. Based on these findings, automobile mechanics who worked with asbestos-containing gaskets may have been exposed to concentrations of airborne asbestos concentrations approximately 100 times lower than the current Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) of 0.1 f/cc.

  9. Workers of the printing industry and hepatic damage.

    Science.gov (United States)

    Sancini, A; Caciari, T; Chighine, A; Gioffrè, P A; Andreozzi, G; Sacchi, L; Giubilati, R; Tomei, G; Suppi, A; Sacco, C; Tomei, F; Rosati, M V

    2014-01-01

    Typesetting industry is still the primary instrument of communication, despite the development of new technological systems. This study focuses on the analysis of the hepatic effects induced by the use of some organic solvents employed in the printing industry. We studied a group of 194 workers: 93 exposed and 101 not exposed. The level of the exposure to chemical pollutants were assessed through the environmental monitoring of blood concentrations and the analysis of airborne substances. The health survey was performed through the collection of the medical history and the use of hepatic tests, which were evaluated by calculating Mean, Standard Deviation, Student's t-test and X² test with Yates Correction, to investigate statistically significant differences in some hepatic parameters: AST, ALT, ALP, GGT, fractional and total bilirubin. The environmental data sometimes exceeded the TLV-TWA. The clinical evaluation of the hepatic parameters showed statistically significant differences as to the hematic concentrations of AST, ALT, GGT. The results we obtained support the hypothesis of a risk among the printing industrial workers attributable to the hepatotoxic solvents. This risk seems to be related to the use of a mixture of solvents, although at low doses, and the analysis of the results obtained confirms the validity of the investigation for the health screening protocol adopted in order to identify subjects and/or population at risk of hepatotoxicity.

  10. Real-time measurement of dust in the workplace using video exposure monitoring: Farming to pharmaceuticals

    International Nuclear Information System (INIS)

    Walsh, P T; Forth, A R; Clark, R D R; Dowker, K P; Thorpe, A

    2009-01-01

    Real-time, photometric, portable dust monitors have been employed for video exposure monitoring (VEM) to measure and highlight dust levels generated by work activities, illustrate dust control techniques, and demonstrate good practice. Two workplaces, presenting different challenges for measurement, were used to illustrate the capabilities of VEM: (a) poultry farming activities and (b) powder transfer operations in a pharmaceutical company. For the poultry farm work, the real-time monitors were calibrated with respect to the respirable and inhalable dust concentrations using cyclone and IOM reference samplers respectively. Different rankings of exposure for typical activities were found on the small farm studied here compared to previous exposure measurements at larger poultry farms: these were mainly attributed to the different scales of operation. Large variations in the ratios of respirable, inhalable and real-time monitor TWA concentrations of poultry farm dust for various activities were found. This has implications for the calibration of light-scattering dust monitors with respect to inhalable dust concentration. In the pharmaceutical application, the effectiveness of a curtain barrier for dust control when dispensing powder in a downflow booth was rapidly demonstrated.

  11. Electrocardiography and serum potassium before and after hemodialysis sessions

    International Nuclear Information System (INIS)

    Tarif, N.; Al-Wakeel, Jamal Saleh; Sulaimani, F.; Memon, Nawaz Ali; Al-Suwaida, Abdul Kareem; Yamani, H.; Bakhsh, Ahmed Jahangir

    2008-01-01

    This study was undertaken to assess potassium level and electrocardiographic (ECG) changes post hemodialysis and whether fall in potassium level during hemodialysis may potentiate cardiac arrythemia. We studied 21 chronic hemodialysis (HD) patients who had their serum electrolytes measured before and after dialysis session and ECG performed at the same time. The patients included 14 females and 7 males with a mean age of 53.1+-15.6 years and range from 26 to 81 years; 9 (43%) patients were diabetics. All the patients had been on dialysis for a minimum of 6 months each Pre-HD serum potassium levels had no correlation with any ECG parameters except a negative correlation with T wave amplitude r=-0.5, p=0.021. ECG parameters significantly changed post-HD; the T wave amplitude decreased and the R wave amplitude increased. A comparatively higher R wave significantly decreased the T to R wave ratio post dialysis. The QRS duration and QTc interval also increased significantly. The patients with post-HD serum potassium of 3.5 mmol/L had a higher R wave amplitude and a significantly less T to R wave ratio (11.8+-9.7 vs 6.4+-5.1, p=0.045 and 0.4+-0.38 vs 1.0+-0.97, p=0.049, respectively. In patients with serum potassium decrement of >2.0 mmol/L, the T to R wave ratio decreased significantly, 0.32+-0.21 vs 0.85+-0.26, p=0.023; The T wave amplitude decreased more than the rise in R wave. Multiple regression analysis did not reveal any relationship of pre or post HD ECG changes and serum potassium, serum calcium or net change in serum potassium post-HD. We conclude that post-HD serum potassium decrement results in a decrease in T to R wave ratio on ECG; this change may have an arrhythmogenic potential. (author)

  12. Hyperkalemia on ECG

    Directory of Open Access Journals (Sweden)

    Bryson Hicks

    2016-09-01

    Full Text Available History of present illness: A 34-year-old diabetic female presented to the emergency department with chest pain status-post AICD firing. She described the pain as a “12 out of 10” which woke her from sleep at 0200, one hour prior to arrival. Vitals were unremarkable. She had no known history of renal failure. Due to frequent ED visits for chronic pain, patient had difficult vascular access and nursing was initially unable to obtain IV access. An abnormal rhythm was noted on the cardiac monitor, and ECG was ordered. Significant findings: Initial ECG shows tall, peaked T waves, most prominently in V3 and V4, as well as QRS widening. These findings are consistent with hyperkalemia, which was promptly treated. Follow-up ECG post-treatment shows narrowing of the QRS complexes and normalization of peaked T waves. Discussion: The etiology of hyperkalemia may be due to an acute insult such as crush injury, drug side effect, or in acute renal failure, but may also occur in the setting of a chronic insult such as chronic kidney disease.1 As potassium rises, several abnormalities can be identified on ECG. Initially the T waves become peaked and the QRS complexes widen.2,3 This can devolve into a wide complex rhythm, ventricular tachycardia, ventricular fibrillation, or asystole. Patients may also experience systemic symptoms such as weakness or paralysis.1 In this particular case, labs showed a potassium of 7.6-mmol/L after initial treatment (see repeat EKG. While the incidence of hyperkalemia in the general population is not defined, the incidence in hospitalized patients is 1.3-10%.4-8 Impaired kidney function is the most common risk factor found in 33-83% of affected patients.4,5,8,9 Treatment for hyperkalemia generally includes IV insulin and IV dextrose and nebulized albuterol for intracellular shift of potassium, IV furosemide and IV fluids for dilution and renal excretion of furosemide, and IV calcium for stabilization of cardiac membranes.2,3

  13. Myocardial scarring on cardiovascular magnetic resonance in asymptomatic or minimally symptomatic patients with “pure” apical hypertrophic cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Kim Kyung-Hee

    2012-07-01

    Full Text Available Abstract Background Late gadolinium enhancement (LGE cardiovascular magnetic resonance (CMR enables state-of-the-art in vivo evaluations of myocardial fibrosis. Although LGE patterns have been well described in asymmetrical septal hypertrophy, conflicting results have been reported regarding the characteristics of LGE in apical hypertrophic cardiomyopathy (ApHCM. This study was undertaken to determine 1 the frequency and distribution of LGE and 2 its prognostic implication in ApHCM. Methods Forty patients with asymptomatic or minimally symptomatic pure ApHCM (age, 60.2 ± 10.4 years, 31 men were prospectively enrolled. LGE images were acquired using the inversion recovery segmented spoiled-gradient echo and phase-sensitive inversion recovery sequence, and analyzed using a 17-segment model. Summing the planimetered LGE areas in all short axis slices yielded the total volume of late enhancement, which was subsequently presented as a proportion of total LV myocardium (% LGE. Results Mean maximal apical wall thickness was 17.9±2.3mm, and mean left ventricular (LV ejection fraction was 67.7 ± 8.0%. All but one patient presented with electrocardiographic negative T wave inversion in anterolateral leads, with a mean maximum negative T wave of 7.2 ± 4.7mm. Nine patients (22.5% had giant negative T waves, defined as the amplitude of ≥10mm, in electrocardiogram. LGE was detected in 130 segments of 30 patients (75.0%, occupying 4.9 ± 5.5% of LV myocardium. LGE was mainly detected at the junction between left and right ventricles in 12 (30% and at the apex in 28 (70%, although LGE-positive areas were widely distributed, and not limited to the apex. Focal LGE at the non-hypertrophic LV segments was found in some ApHCM patients, even without LGE of hypertrophied apical segments. Over the 2-year follow-up, there was no one achieving the study end-point, defined as all-cause death, sudden cardiac death and hospitalization for heart failure

  14. Influence of presenting electrocardiographic findings on the treatment and outcomes of patients with non-ST-segment elevation myocardial infarction.

    Science.gov (United States)

    Patel, Jigar H; Gupta, Raghav; Roe, Matthew T; Peng, S Andrew; Wiviott, Stephen D; Saucedo, Jorge F

    2014-01-15

    The influence of the presenting electrocardiographic (ECG) findings on the treatment and outcomes of patients with non-ST-segment elevation myocardial infarction (NSTEMI) has not been studied in contemporary practice. We analyzed the clinical characteristics, in-hospital management, and in-hospital outcomes of patients with NSTEMI in the Acute Coronary Treatment and Intervention Outcomes Network Registry-Get With The Guidelines (ACTION Registry-GWTG) according to the presenting ECG findings. A total of 175,556 patients from 485 sites from January 2007 to September 2011 were stratified by the ECG findings on presentation: ST depression (n = 40,146, 22.9%), T-wave inversions (n = 24,627, 14%), transient ST-segment elevation (n = 5,050, 2.9%), and no ischemic changes (n = 105,733, 60.2%). Patients presenting with ST-segment depression were the oldest and had the greatest prevalence of major cardiac risk factors. Coronary angiography was performed most frequently in the transient ST-segment elevation group, followed by the T-wave inversion, ST-segment depression, and no ischemic changes groups. The angiogram revealed that patients with ST-segment depression had more left main, proximal left anterior descending, and 3-vessel coronary artery disease and underwent coronary artery bypass grafting most often. In contrast, patients with transient ST-segment elevation had 1-vessel CAD and underwent percutaneous coronary intervention the most. The unadjusted mortality was highest in the ST-segment depression group, followed by the no ischemic changes, transient ST-segment elevation, and T-wave inversion group. Adjusted mortality using the ACTION Registry-GWTG in-hospital mortality model with the no ischemic changes group as the reference showed that in-hospital mortality was similar in the transient ST-segment elevation (odds ratio 1.15, 95% confidence interval 0.97 to 1.37; p = 0.10), higher in the ST-segment depression group (odds ratio 1.46, 95% confidence interval 1

  15. Reappearance of beriberi heart disease in Japan. A study of 23 cases.

    Science.gov (United States)

    Kawai, C; Wakabayashi, A; Matsumura, T; Yui, Y

    1980-09-01

    Twenty-three Japanese patients with beriberi heart disease, 17 of them teenagers, were studied. The recent tendency for teenagers to take excessive sweet carbonated soft drinks, instant noodles and powermill-polished rice readily induces relative thiamine deficiency. A sudden increase in thiamine requirements due to strenuous exercise can result in overt beriberi heart disease. Alcohol had nothing to do with the development of the disease. Characteristic features commonly seen in teenage patients include peripheral edema, low peripheral vascular resistance, increased venous pressure enlarged heart, T wave abnormalities, hyperkinetic circulatory state and increased circulating blood volume. Thiamine deficiency was confirmed by a decrease in blood thiamine concentration, a decrease in erythrocyte transketolase activity and an increase in thiamine pyrophosphate (TPP) effect. Improvement was rapidly achieved with thiamine administration, balanced nutrition and rest, especially in the teenage patients. Increased circulating blood volume was useful in differentiating beriberi heart disease from hyperthyroidism.

  16. Electrocardiographic evaluation of two anesthetic combinations in dogs

    Directory of Open Access Journals (Sweden)

    Tárraga K.M.

    2000-01-01

    Full Text Available This study aimed to investigate electrocardiographic changes in dogs aged 5 years or more submitted to two anesthetic combinations: atropine, levomeprazine, thiopental and halothane (ALTH, and atropine, tiletamine and zolazepam (ATZ. Forty dogs (24 males/16 females weighing 5-24kg, were used. Dogs had no cardiac problems and were submitted to tartarectomy. All animals were submitted to two electrocardiograms (ECG, one before anesthesia and other immediately before surgery. The dogs were divided into two groups: group 1 received ALTH and group 2 received ATZ. Alterations in the ST segment, T wave, cardiac rhythm and a significant reduction of vagal tonus index were observed in both groups, but in group 2 a significant reduction of the PR and QT intervals and an increase in heart rate were also observed. These data suggest that the ALTH combination caused fewer changes in the ECG than the ATZ combination.

  17. Left ventricular lipoma with pseudoaneurysm-like appearance.

    Science.gov (United States)

    Kawarai, Shun-ichi; Yaginuma, Gen-ya; Abe, Kazuo; Hamasaki, Azumi; Ishikawa, Kazunori; Tanaka, Daizo

    2010-06-01

    We describe an extremely rare cardiac lipoma, with electrocardiographic changes in ST segments and T waves, suggesting ischemic heart disease. The abnormal electrocardiogram was identified during a routine physical examination of an asymptomatic 57-year-old man. Coronary angiography showed no stenotic or occlusive lesions in the coronary arteries except that the left anterior descending artery followed a winding course in the apical region. Left ventriculography revealed a pseudoaneurysm-like mass around the apical portion. Computed tomography and magnetic resonance imaging revealed a cardiac lipoma that communicated with the left ventricle and resembled a pseudoaneurysm. After complete resection of the lipoma and left ventricle patch plasty, the postoperative course was uneventful. Histologically, the tumor was an intramyocardiac lipoma with no evidence of malignancy. To our knowledge, we are the first to describe an intramyocardiac lipoma resembling a left ventricle pseudoaneurysm.

  18. A case of appropriate inappropriate device therapy: Hyperkalemia-induced ventricular oversensing

    Science.gov (United States)

    Oudit, Gavin Y; Cameron, Doug; Harris, Louise

    2008-01-01

    The present case describes a patient who received inappropriate, but potentially life-saving, therapy from her implantable cardioverter defibrillator (ICD) in the setting of acute hyperkalemia (plasma potassium concentration = 8 mM). Hyperkalemia was associated with the development of a slow sinusoidal ventricular tachycardia, at a rate of 100 beats/min to 125 beats/min (610 ms to 480 ms) in a patient who is pacemaker-dependent. There was associated fractionation of the ICD electrogram and T wave oversensing, leading to ventricular oversensing with resultant detection in the ventricular fibrillation rate zone. This was followed by shock therapy, even though the ventricular tachycardia rate was below the programmed detection rate of the ICD. The subsequent emergency treatment of the hyperkalemia normalized the electrogram, corrected the ventricular oversensing and arrhythmia, and restored rate-adaptive single-chamber ventricular pacing. PMID:18340383

  19. Prognostic value of an electrocardiogram at rest and exercise test in patients admitted with suspected acute myocardial infarction, in whom the diagnosis is not confirmed

    DEFF Research Database (Denmark)

    Madsen, J K; Hommel, E; Hansen, J F

    1987-01-01

    . Impaired prognosis was found in patients with negative T waves or ST depression at rest or with ST--T abnormalities or angina pectoris during exercise. Patients with ST depression or elevation, Q wave or intraventricular block at rest. ST abnormalities during exercise or both constituted a high-risk group......The prognosis following discharge in 217 patients admitted with suspected acute myocardial infarction (AMI) due to chest pain, but in whom AMI was not confirmed, was related to the electrocardiogram (ECG) at rest and a symptom-limited exercise test. The patients were followed for 12 to 24 months...... in the ECG at rest and during exercise can be used to identify high and low risk patients....

  20. Cardiotoxicity in Asymptomatic Patients Receiving Adjuvant 5-fluorouracil

    DEFF Research Database (Denmark)

    Nielsen, Karin; Polk, Anne; Nielsen, Dorte Lisbet

    2014-01-01

    Evolving evidence of cardiotoxicity in cancer patients treated with 5-fluorouracil (5-FU) has been reported. We report two different clinical manifestations of asymptomatic 5-FU-associated cardiotoxicity in patients operated for colorectal cancer and treated with adjuvant chemotherapy of 5-FU...... (bolus-injection and continuous infusion for 46 hours), folinic acid and oxaliplatin (FOLFOX). For a research study evaluating cardiac events during 5-FU treatment, Holter monitoring, electrocardiogram (ECG) and echocardiography were done and cardiac markers monitored before and during the first...... and hyperlipidemia as well as an incidental finding of negative T-waves in electrocardiogram years before 5-FU treatment. No subjective cardiac symptoms were described during infusion, but approximately 12 hours after infusion she suffered from cardiac arrest but was revived. Subsequent analysis of the Holter...

  1. QT Prolongation Complicated with Torsades de Pointes in Prosthetic Mitral Valve Endocarditis: A Case Report

    Directory of Open Access Journals (Sweden)

    A. Tounsi

    2012-01-01

    Full Text Available We present the case of a 49-year-old male patient with prosthetic mitral valve endocarditis associated with QT prolongation and torsades de pointes. He was asymptomatic until the end of January 2012, when he was admitted to our hospital emergency unit because of syncope, fever, and suspicion of endocarditis. Cardiologic evaluation was requested and the transthoracic (TTE and transesophageal (TEE echocardiograms revealed vegetations on the prosthetic mitral valve. All cultures were positive for methicillin-sensitive Staphylococcus aureus. The corrected QT (QTc interval was markedly prolonged upon admission (QTc 540 ms. He experienced torsades de pointes (TdP several times and he was recovered after bystander cardiopulmonary resuscitation. The clinical course and the long QTc interval with deep inverted T wave were completely normalized 4 weeks after. He continued on triple antibiotic therapy for 45 days with a good revolution. The clinical features and the possible mechanisms of QT prolongation (inflammation, infection of this patient are discussed.

  2. Algorithm for the automatic computation of the modified Anderson-Wilkins acuteness score of ischemia from the pre-hospital ECG in ST-segment elevation myocardial infarction

    DEFF Research Database (Denmark)

    Fakhri, Yama; Sejersten-Ripa, Maria; Schoos, Mikkel Malby

    2017-01-01

    BACKGROUND: The acuteness score (based on the modified Anderson-Wilkins score) estimates the acuteness of ischemia based on ST-segment, Q-wave and T-wave measurements obtained from the electrocardiogram (ECG) in patients with ST Elevation Myocardial Infarction (STEMI). The score (range 1 (least...... the acuteness score. METHODS: We scored 50 pre-hospital ECGs from STEMI patients, manually and by the automated algorithm. We assessed the reliability test between the manual and automated algorithm by interclass correlation coefficient (ICC) and Bland-Altman plot. RESULTS: The ICC was 0.84 (95% CI 0.......72-0.91), PECGs, all within the upper (1.46) and lower (-1.12) limits...

  3. Coronary artery calcification and ECG pattern of left ventricular hypertrophy or strain identify different healthy individuals at risk

    DEFF Research Database (Denmark)

    Diederichsen, Søren Zöga; Gerke, Oke; Olsen, Michael Hecht

    2013-01-01

    PURPOSE:: To improve risk stratification for development of ischaemic heart disease, several markers have been proposed. Both the presence of coronary artery calcification (CAC) and ECG pattern of left ventricular hypertrophy/strain have been shown to provide independent prognostic information....... In this study, we investigated the association between established risk factors, ECG measurements and the presence of coronary artery calcification. METHOD:: A random sample of healthy men and women aged 50 or 60 years were invited to the screening study. Established risk factors were measured. A noncontrast...... computed tomographic (CT) scan was performed to assess the CAC score. ECG analysis included left ventricular hypertrophy (LVH) using the Sokolow-Lyon criteria and the Cornell voltage × QRS duration product, and strain pattern based on ST segment depression and T-wave abnormalities. The association between...

  4. Hyperkalemia masked by pseudo-stemi infarct pattern and cardiac arrest.

    Science.gov (United States)

    Peerbhai, Shareez; Masha, Luke; DaSilva-DeAbreu, Adrian; Dhoble, Abhijeet

    2017-12-01

    Hyperkalemia is a common electrolyte abnormality and has well-recognized early electrocardiographic manifestations including PR prolongation and symmetric T wave peaking. With severe increase in serum potassium, dysrhythmias and atrioventricular and bundle branch blocks can be seen on electrocardiogram. Although cardiac arrest is a worrisome consequence of untreated hyperkalemia, rarely does hyperkalemia electrocardiographically manifest as acute ischemia. We present a case of acute renal failure complicated by malignant hyperkalemia and eventual ventricular fibrillation cardiac arrest. Recognition of this disorder was delayed secondary to an initial ECG pattern suggesting an acute ST segment elevation myocardial infarction (STEMI). Emergent coronary angiography performed showed no evidence of coronary artery disease. Pseudo-STEMI patterns are rarely seen in association with acute hyperkalemia and are most commonly described with patient without acute cardiac symptomatology. This is the first such case presenting concurrently with cardiac arrest. A brief review of this rare pseudo-infarct pattern is also given.

  5. Presentation of a case with Wellens syndrome

    Directory of Open Access Journals (Sweden)

    Luis A. Rodríguez López

    2016-06-01

    Full Text Available This case report is about a 56-year-old male, farm worker with a history of being a smoker and suffering from high blood pressure, who was admitted at the Cardiology Care Department with the diagnosis of coronary artery disease –unstable angina–, because of chest pain related to physical effort and changes in the appearance threshold. Rest-electrocardiogram, painless, shows deep, symmetric negative T waves in anterior wall, without enzyme elevation; but during admission the patient evolves quickly, clinically and electrically, to an extensive anterior wall acute myocardial infarction, without responding to the fibrinolytic reperfusion therapy, and showing a ventricular tachycardia degenerating into ventricular fibrillation. There was no response to the maneuvers of cardiovascular resuscitation, thus, he dies. It is diagnosed postmortem as a Wellens syndrome, because necropsy showed severe atherosclerotic disease of the proximal segment of the left anterior descending coronary artery with extensive anterior transmural infarction.

  6. [Myocardial infarction (NSTEMI) in a young patient with coronary aneurysm].

    Science.gov (United States)

    Kulzer, M J; Mooyaart, E A Q; Hetterich, H

    2012-04-01

    A 28-year-old man without a significant past medical history presented to our emergency department with severe chest pain and dyspnoa. Vital signs and the rest of the physical examination were unremarkable. The electrocardiogram showed T-wave inversions and the cardiac enzymes were elevated. Angiocardiography showed an aneurysm of the right coronary artery and a thrombus formation in its distal part. Intracoronary thrombolytic therapy was attempted an oral anticoagulation was started. Further investigations did not find the cause of the aneurysmatic RCA. The patient had no further episode of chest pain. Acute coronary syndrome is a rare finding in patients under the age of 30 years. Coronary aneurysms with associated thrombus can be the cause of it. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Electrocardiographic changes is patients with esophageal carcinoma exposed to radiotherapy by a continuous and split course

    Energy Technology Data Exchange (ETDEWEB)

    Sarkisyan, Yu Kh; Goncharova, I M; Kallistova, L P; Syromyatnikova, E N; Slaviner, S I; Abramchenko, Yu A [Nauchno-Issledovatel' skij Inst. Rentgenologii i Radiologii, Moscow (USSR)

    1980-10-01

    An analysis of clinical, electrocardiographic, roentgenological and biochemical changes was made in 170 patients with esophageal carcinoma before, during and after radiation therapy conducted by a continuous (34 patients) and split course (136 patients). A rise in sinus tachycardia, appearance of extrasystolia and His' bundle right branch block, lowering of the ST-segment, flattening or appearance of negative T wave, an increase in the activity of creatine phosphokinase and aspartate aminotransferase in the blood serum were noted in a number of patients during radiation therapy. The changes were observed more often and were more marked in patients who had received continuous telegammatherapy. Irrespective of the method of radiotherapy in the restoration of the processes of excitation and conduction, improvement of metabolism in the cardiac muscle, a decrease in dysproteinemia, an increase in the content of electrolytes in the blood were noted.

  8. Apical ballooning with mid-ventricular obstruction: the many faces of Takotsubo cardiomyopathy

    Science.gov (United States)

    Spadotto, Veronica; Elmaghawry, Mohamed; Zorzi, Alessandro; Migliore, Federico; Marra, Martina Perazzolo

    2013-01-01

    Takotsubo cardiomyopathy (TTC) is a transient left ventricular dysfunction due to akinesia of the left-ventricular (LV) mid-apical segments (apical ballooning), which can cause severe reduction in LV systolic function. The typical clinical picture of TTC include chest pain, electrocardiographic changes consisting of mild ST-segment elevation followed by diffuse deep T-wave inversion, QTc interval prolongation and mild troponin release in the absence of significant coronary stenoses. The syndrome often affects post-menopausal women and is triggered by sympathetic overstimulation, like intense physical or emotional stress, so that it is called the “broken heart syndrome”. Although left-ventricular systolic dysfunction usually fully recovers within few days, heart failure can still complicate the early phase. We report a case of stress-induced cardiomyopathy that had full recovery after 4 weeks of follow up. The main electrocardiographic, angiographic and imaging features are discussed. PMID:24689016

  9. Ostial left main coronary stenosis in a frequent flyer.

    LENUS (Irish Health Repository)

    O'Sullivan, John F

    2009-05-15

    A 52 year old gentleman presented with chest pain, after a long distance flight from India; he had made long haul flights every 2 weeks over the last 5 years as part of his job. His ECG revealed T wave inversion in leads V1-3. Cardiac biomarkers including troponin were negative; we proceeded to exercise stress testing (EST). This revealed 2 mm ST depression at 2 min of the standard Bruce protocol, associated with chest pain. He was taken immediately to the coronary catheterization laboratory; engagement of the left main caused pressure damping with 6 French, then 5 French diagnostic Judkins left 4 catheters. An ostial left main stenosis was seen; the right and left coronary trees otherwise had no significant stenoses. He had normal LV function. He underwent inpatient CABG 7 days later.

  10. Takotsubo Cardiomyopathy and Catatonia in the Setting of Benzodiazepine Withdrawal

    Directory of Open Access Journals (Sweden)

    Teng J. Peng

    2016-01-01

    Full Text Available We report two serious and unusual complications of benzodiazepine withdrawal in a single patient: takotsubo cardiomyopathy and catatonia. This 61-year-old female patient was brought to the emergency department with lethargy and within hours had declined into a state of catatonia. Although there was never a complaint of chest pain, ECG showed deep anterior T-wave inversions and cardiac enzymes were elevated. An echocardiogram was consistent with takotsubo cardiomyopathy. She later received 1 mg of midazolam and within minutes had resolution of catatonic symptoms. Careful history revealed that she had omitted her daily dose of lorazepam for 3 days prior to admission. To our knowledge, the case presented herein is the first report of simultaneous catatonia and takotsubo cardiomyopathy in the setting of benzodiazepine withdrawal. The pathogenesis of both conditions is poorly understood but may be indirectly related to the sudden decrease in γ-aminobutyric acid (GABA signaling during benzodiazepine withdrawal.

  11. Myocardial infarction after dipyridamole-assisted thallium-201 imaging

    International Nuclear Information System (INIS)

    Biddle, P.; Lanspa, T.J.; Mohiuddin, S.M.; Malesker, M.A.; Hilleman, D.E.

    1989-01-01

    A 77-year-old woman with suspected coronary artery disease underwent an oral dipyridamole/thallium-201 myocardial imaging study. Approximately 75 minutes after ingestion of dipyridamole 300 mg suspension, the patient developed chest pain, hypotension, nausea, and diaphoresis. An electrocardiogram revealed ST-T wave changes suggestive of inferior ischemia. Appropriate therapeutic measures, including aminophylline and nitroglycerin, were instituted. Delayed thallium images revealed reversible ischemia in the anteroseptal and posterobasal regions with a fixed defect in the inferobasal region. Cardiac enzyme studies were also indicative of acute myocardial injury. The patient subsequently underwent coronary arteriography and four-vessel coronary artery bypass grafting and was discharged without further complication. This report raises concerns about the potential danger of dipyridamole in patients with severe coronary artery stenosis and collateral circulation. Prophylactic aminophylline should be considered in these patients

  12. Coronary arterio-venous fistula associated acute coronary syndrome: A case-report and review of literature

    Directory of Open Access Journals (Sweden)

    V.H. Contreras-Gutiérrez

    2017-01-01

    Full Text Available A 56-year-old woman with no medical history presented to the emergency department complaining of oppressive chest pain of three hours of duration triggered by walking. An electrocardiogram (ECG performed at hospital admission showed ST-segment depression and T-wave inversion in left precordial and inferior leads. Serum troponin I levels were above the normal values. Non ST-segment elevation acute coronary syndrome (NSTEACS was diagnosed and an invasive approach with a percutaneous coronary intervention was performed. No obstructive coronary lesions were observed. However a tortuous coronary fistula emerging from the left-anterior descending coronary artery to the pulmonary artery was observed. Coronary arterio-venous fistulas are present in 0.002% of the general population and in 0.25% of patients undergoing cardiac catheterization for any cause. Most of them are asymptomatic. Ischemic symptoms may develop but are infrequent in patients with no atherosclerotic disease.

  13. Phase 2 reentry in man

    DEFF Research Database (Denmark)

    Thomsen, P.E.B.; Jørgensen, R.M.; Kanters, J.K.

    2005-01-01

    -wave changes documented in the last sinus beat prior to ventricular extrasystoles are in agreement with phase 2 reentry, suggesting that this may be the responsible mechanism for ventricular extrasystoles and ventricular tachycardia/fibrillation. The phenomenon has been demonstrated in only animal experiments...... phase 2 reentry, demonstrated in animal experiments to initiate ventricular extrasystoles, ventricular tachycardia, and ventricular fibrillation, also plays a role in humans. METHODS We examined 18 patients with ventricular extrasystoles and/or ventricular tachycardia by signal averaging of the ECG...... patients undergoing radiofrequency ablation. Eight of the 11 patients had right ventricular outflow tract extrasystoles. RESULTS In six of the seven patients in group A, we demonstrated significant ST-elevation and/or T-wave changes in the sinus beat preceding ventricular extrasystoles compared...

  14. Electrocardiogram assessment in non-anaesthetized clinically healthy agouti (Dasyprocta primnolopha, Wagler 1831

    Directory of Open Access Journals (Sweden)

    Anaemilia das N. Diniz

    2013-12-01

    Full Text Available The agouti is one of the most intensely hunted species throughout the Amazon and the semiarid regions of north-eastern Brazil. Considering the current tendency of wild animal management in captivity, the objective of this study was to determine heart reference values for agouti raised in captivity, based on electrocardiographic assessments (ECG. Adult agouti were selected without clinical signs of heart disease (n=30. The animals were restrained physically and then the ECG was performed. Standardized measurements were taken to establish the statistical analysis of the data. Analysis of the QRS complex showed values compatible with previous reports in peer animals and the limited data available for other wild and exotic species, except for the T wave that showed similar amplitude to the R wave in all the animals studied. The data obtained provided the first reference values for ECG tracings in agouti, contributing to a better understanding of heart electrophysiology in identifying myocardial pathology in these animals.

  15. [Parameters of cardiac muscle repolarization on the electrocardiogram when changing anatomical and electric position of the heart].

    Science.gov (United States)

    Chaĭkovskiĭ, I A; Baum, O V; Popov, L A; Voloshin, V I; Budnik, N N; Frolov, Iu A; Kovalenko, A S

    2014-01-01

    While discussing the diagnostic value of the single channel electrocardiogram a set of theoretical considerations emerges inevitably, one of the most important among them is the question about dependence of the electrocardiogram parameters from the direction of electrical axis of heart. In other words, changes in what of electrocardiogram parameters are in fact liable to reflect pathological processes in myocardium, and what ones are determined by extracardiac factors, primarily by anatomic characteristics of patients. It is arguable that while analyzing electrocardiogram it is necessary to orient to such physiologically based informative indexes as ST segment displacement. Also, symmetry of the T wave shape is an important parameter which is independent of patients anatomic features. The results obtained are of interest for theoretical and applied aspects of the biophysics of the cardiac electric field.

  16. MagnetoHemoDynamics in the aorta and electrocardiograms

    International Nuclear Information System (INIS)

    Martin, Vincent; Drochon, Agnès; Fokapu, Odette; Gerbeau, Jean-Frédéric

    2012-01-01

    This paper addresses a complex multi-physical phenomenon involving cardiac electrophysiology and hemodynamics. The purpose is to model and simulate a phenomenon that has been observed in magnetic resonance imaging machines: in the presence of a strong magnetic field, the T-wave of the electrocardiogram (ECG) gets bigger, which may perturb ECG-gated imaging. This is due to a magnetohydrodynamic (MHD) effect occurring in the aorta. We reproduce this experimental observation through computer simulations on a realistic anatomy, and with a three-compartment model: inductionless MHD equations in the aorta, bi-domain equations in the heart and electrical diffusion in the rest of the body. These compartments are strongly coupled and solved using finite elements. Several benchmark tests are proposed to assess the numerical solutions and the validity of some modeling assumptions. Then, ECGs are simulated for a wide range of magnetic field intensities (from 0 to 20 T). (paper)

  17. Electrocardiographic Characterization of Cardiac Hypertrophy in Mice that Overexpress the ErbB2 Receptor Tyrosine Kinase

    DEFF Research Database (Denmark)

    Sysa-Shah, Polina; Sørensen, Lars L; Abraham, M Roselle

    2015-01-01

    , the ECG recordings of ErbB2(tg) mice were characterized by higher P- and R-wave amplitudes, broader QRS complexes, inverted T waves, and ST interval depression. Pearson's correlation matrix analysis of combined WT and ErbB2(tg) data revealed significant correlation between heart weight and the ECG...... parameters of QT interval (corrected for heart rate), QRS interval, ST height, R amplitude, P amplitude, and PR interval. In addition, the left ventricular posterior wall thickness as determined by echocardiography correlated with ECG-determined ST height, R amplitude, QRS interval; echocardiographic left...... ventricular mass correlated with ECG-determined ST height and PR interval. In summary, we have determined phenotypic ECG criteria to differentiate ErbB2(tg) from WT genotypes in 98.8% of mice. This inexpensive and time-efficient ECG-based phenotypic method might be applied to differentiate between genotypes...

  18. Ventricular repolarization measures for arrhythmic risk stratification

    Institute of Scientific and Technical Information of China (English)

    Francesco Monitillo; Marta Leone; Caterina Rizzo; Andrea Passantino; Massimo Iacoviello

    2016-01-01

    Ventricular repolarization is a complex electrical phenomenon which represents a crucial stage in electrical cardiac activity. It is expressed on the surface electrocardiogram by the interval between the start of the QRS complex and the end of the T wave or U wave(QT). Several physiological, pathological and iatrogenic factors can influence ventricular repolarization. It has been demonstrated that small perturbations in this process can be a potential trigger of malignant arrhythmias, therefore the analysis of ventricular repolarization represents an interesting tool to implement risk stratification of arrhythmic events in different clinical settings. The aim of this review is to critically revise the traditional methods of static analysis of ventricular repolarization as well as those for dynamic evaluation, their prognostic significance and the possible application in daily clinical practice.

  19. Monitoring of electric-cardio signals based on DSP

    Science.gov (United States)

    Yan, Yi-xin; Sun, Hui-nan; Lv, Shuang

    2008-10-01

    Monitoring of electric-cardio signals is the most direct method of discovering heart diseases. This article presents an electric-cardio signal acquisition and processing system based on DSP. According to the features of electric-cardio signals, the proposed system uses the AgCl electrode as electric-cardio signals sensor, and acquires analog signals with AD620 as the prepositional amplifier, and the digital system equipped is with TMS320LF2407A DSP. The design of digital filter and the analysis of heart rate variation are realized by programming in the DSP. Finally the ECG is obtained with P and T waves along with obvious QRS multi-wave characteristics. The system has low power dissipation, low cost and high precision, which meets the requirements for medical instruments.

  20. Cardiac complications in diphtheria and predictors of outcomes.

    Science.gov (United States)

    Samdani, Sunil; Jain, Avani; Meena, Vinod; Meena, C B

    2018-01-01

    To study the cardiac complications in diphtheria patients and to study the predictors of outcomes. Single centre prospective analysis of cardiac complications in diphtheria patients. In this study, there were 60 patients diagnosed with diphtheria with ECG changes. The ECG changes seen were sinus tachycardia (68.3%), T wave inversion (20%), ST segment depression (13.3%), right bundle branch block (5%), multiple atrial ectopics (3.3%). The case fatality rate in our study was 25% (15 patients). High CPK-MB, myoglobulin and cardiac troponin levels were associated with cardiac mortality. In our study, cardiac troponin T had the highest sensitivity (80%) and CK-MB had the highest specificity (95.56%). Cardiac involvement is a common complication of infection with C. diphtheria and is associated with high mortality. As diphtheria can be prevented by adequate vaccination, efforts should be maximized for high vaccine coverage with booster doses. Copyright © 2017. Published by Elsevier B.V.

  1. 'Variant' angina: Evidence for small vessel coronary artery spasm

    International Nuclear Information System (INIS)

    Pfisterer, M.; Mueller-Brand, J.; Cueni, T.; Luetold, B.; Burkart, F.; Basel Univ.

    1980-01-01

    A unique case of 'variant' angina pectoris has been observed in a patient with normal coronary arteries and typical chest pain appearing spontaneously at rest, and repeatedly provoked by ergonovine maleate (0.1 mg iv) associated with large transmural perfusion defects on 201 TI-imaging (after ergonovine) and a marked increase in T wave voltage despite no demonstrable spasm of a major coronary artery after the same doses of ergonovine. While saline solution could not provoke chest pain and treatment with a beta-blocking agent increased the frequency of ischemic attacks, a calcium antangonist therapy reduced and eventually eliminated the attacks. Thus, this case provides evidence for yet another aspect of a 'variant' form of angina pectoris: small vessel coronary artery spasm. (orig.) [de

  2. Metabolism of inhaled 239PuO2 particles in rat pulmonary

    International Nuclear Information System (INIS)

    Su Yuanfu; Guo Yao

    1986-01-01

    The changes in myocardial ultrastructure showed distinct dose-effect relation ship. Myocardial fibres maintained normal feature at doses below 150 Gy, even though small intestine epithelial lining was damaged and myocardial microvessels degenerated apparently. With the radiation dose increased to 250 Gy, degeneration and destruction of myocardial fibrils appeared. This events revealed the direct dependence of myocardial fibrillar changes to radiation doses but not to vascular lesion. Electrocardiography showed S-T segment in addition to the prolongation of Q-T intervals and T waves, while myocardial fibrils, myocardial mitochondria, T and L tubular systems and intercalate discs all underwent alterations. These abnormalities in dicated aberration of depolarization and repolarization in the animals heart. In parallel with the electrocardiographic changes, the level of plasma LDH 1 increased, which suggested cellular lesion and leakage of intracellular enzymes. All above changes supported the concept on presence of a 'cardio-vascular type' in acute radiation sickness

  3. The congenital long QT syndrome Type 3: An update

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    Andrés Ricardo Pérez-Riera

    2018-01-01

    Full Text Available Congenital long QT syndrome type 3 (LQT3 is the third in frequency compared to the 15 forms known currently of congenital long QT syndrome (LQTS. Cardiac events are less frequent in LQT3 when compared with LQT1 and LQT2, but more likely to be lethal; the likelihood of dying during a cardiac event is 20% in families with an LQT3 mutation and 4% with either an LQT1 or an LQT2 mutation. LQT3 is consequence of mutation of gene SCN5A which codes for the Nav1.5 Na+ channel α-subunit and electrocardiographically characterized by a tendency to bradycardia related to age, prolonged QT/QTc interval (mean QTc value 478 ± 52 ms, accentuated QT dispersion consequence of prolonged ST segment, late onset of T wave and frequent prominent U wave because of longer repolarization of the M cell across left ventricular wall.

  4. Reconstruction of electrocardiogram using ionic current models for heart muscles.

    Science.gov (United States)

    Yamanaka, A; Okazaki, K; Urushibara, S; Kawato, M; Suzuki, R

    1986-11-01

    A digital computer model is presented for the simulation of the electrocardiogram during ventricular activation and repolarization (QRS-T waves). The part of the ventricular septum and the left ventricular free wall of the heart are represented by a two dimensional array of 730 homogeneous functional units. Ionic currents models are used to determine the spatial distribution of the electrical activities of these units at each instant of time during simulated cardiac cycle. In order to reconstruct the electrocardiogram, the model is expanded three-dimensionally with equipotential assumption along the third axis and then the surface potentials are calculated using solid angle method. Our digital computer model can be used to improve the understanding of the relationship between body surface potentials and intracellular electrical events.

  5. Giant U waves: an important clinical clue

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    Verma N

    2011-04-01

    Full Text Available Nitin Verma, Vincent M Figueredo, Allan M Greenspan, Gregg S PressmanAlbert Einstein Medical Center, Philadelphia, PA, USAAbstract: Electrocardiographic U waves are a common clinical finding, and yet are poorly understood by many physicians. They can be seen in many clinical conditions, most importantly hypokalemia and ischemic heart disease. Over the years, many theories have been put forth to explain their origin. While still not completely understood, it now appears that mechanoelectrical interactions are responsible for normal U waves. Pathologic U waves may be seen in ischemic heart disease where they sometimes point to acute ischemic events. The large U waves of hypokalemia are most likely not true U waves but rather the terminal deflection in a bifid T wave.Keywords: U waves, hypokalemia, myocardial ischemia, electrocardiogram

  6. Las formas con estribillo en la lírica oral del Medioevo

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    Beltran, Vicenç

    2002-12-01

    Full Text Available This essay analyses the musical and stanza forms pertaining to the most archaic poetical categories to be found in the romance languages, in relation to the Medieval oral tradition and to non-cortes literary texts. Recourse to the "zejel", apart from its obvious Arabic origins, can be traced in Provencal to the pre-troubadour period ("Laissatz estar lo gazel", and the first known instances of "rotrouenge" appeared in the X century in the Alba de Fleury, and the "rondeau", in its simplest form (strophic verses alternating with a refrain, appeared in the works of the writer Hilario el Inglés, a disciple of Abelardo. All the latter refer to hybrid texts, either in Latin (Arabic, where "moaxajas" are concerned or some early romance tongue or other, which is difficult to identify at times; however, there is no doubt that we can plainly discern the essential traits of what these forms would resemble during the troubadour period and throughout the whole of the Lower Middle Ages.

    En este trabajo se estudian las formas estróficas y musicales de los géneros poéticos más arcaicos en las letras romances, vinculados a la tradición oral del Medioevo y a registros literarios no corteses. El zéjel, además de sus conocidos precedentes árabes, remonta en provenzal al período pretrovadoresco ("Laissatz estar lo gazel", el ejemplo más antiguo de rotrouenge remonta hasta el siglo X en el Alba de Fleury y el rondeau, en su forma más simple (versos de estrofa que alternan con versos de estribillo aparece en la obra del escritor Hilario el Inglés, discípulo de Abelardo. En todos estos casos nos hallamos ante textos híbridos, en latín (árabe, en el caso de las moaxajas y algún romance primitivo, a veces difícil de identificar; sin embargo, en todos estos casos podemos reconocer sin lugar a dudas los aspectos esenciales de cómo serán estas formas en el período trovadoresco y durante toda la Baja Edad Media.

  7. Prevention of adenosine A2A receptor activation diminishes beat-to-beat alternation in human atrial myocytes.

    Science.gov (United States)

    Molina, Cristina E; Llach, Anna; Herraiz-Martínez, Adela; Tarifa, Carmen; Barriga, Montserrat; Wiegerinck, Rob F; Fernandes, Jacqueline; Cabello, Nuria; Vallmitjana, Alex; Benitéz, Raúl; Montiel, José; Cinca, Juan; Hove-Madsen, Leif

    2016-01-01

    Atrial fibrillation (AF) has been associated with increased spontaneous calcium release from the sarcoplasmic reticulum and linked to increased adenosine A2A receptor (A2AR) expression and activation. Here we tested whether this may favor atrial arrhythmogenesis by promoting beat-to-beat alternation and irregularity. Patch-clamp and confocal calcium imaging was used to measure the beat-to-beat response of the calcium current and transient in human atrial myocytes. Responses were classified as uniform, alternating or irregular and stimulation of Gs-protein coupled receptors decreased the frequency where a uniform response could be maintained from 1.0 ± 0.1 to 0.6 ± 0.1 Hz; p < 0.01 for beta-adrenergic receptors and from 1.4 ± 0.1 to 0.5 ± 0.1 Hz; p < 0.05 for A2ARs. The latter was linked to increased spontaneous calcium release and after-depolarizations. Moreover, A2AR activation increased the fraction of non-uniformly responding cells in HL-1 myocyte cultures from 19 ± 3 to 51 ± 9 %; p < 0.02, and electrical mapping in perfused porcine atria revealed that adenosine induced electrical alternans at longer cycle lengths, doubled the fraction of electrodes showing alternation, and increased the amplitude of alternations. Importantly, protein kinase A inhibition increased the highest frequency where uniform responses could be maintained from 0.84 ± 0.12 to 1.86 ± 0.11 Hz; p < 0.001 and prevention of A2AR-activation with exogenous adenosine deaminase selectively increased the threshold from 0.8 ± 0.1 to 1.2 ± 0.1 Hz; p = 0.001 in myocytes from patients with AF. In conclusion, A2AR-activation promotes beat-to-beat irregularities in the calcium transient in human atrial myocytes, and prevention of A2AR activation may be a novel means to maintain uniform beat-to-beat responses at higher beating frequencies in patients with atrial fibrillation.

  8. Avaliação da influência de alterações cardíacas na ultrassonografia vascular periférica de idosos

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    Alcides José Araújo Ribeiro

    Full Text Available Resumo Contexto As cardiopatias podem causar alterações no formato das ondas da ultrassonografia vascular (UV em vasos periféricos. Essas alterações, tipicamente bilaterais e sistêmicas, são pouco conhecidas e estudadas. Objetivo Avaliar as ondas periféricas da UV de pacientes idosos para identificar alterações decorrentes de cardiopatias. Métodos Foram estudados 183 pacientes idosos submetidos a UV periférica no ano de 2014. Resultados Foram avaliados 102 mulheres (55,7% e 81 homens (44,3% com idade entre 60 e 91 anos (média de 70,4±7,2 anos. Encontraram-se alterações pela UV em 84 pacientes (45,9%. Foram identificadas 138 alterações de oito dos 13 tipos descritos na literatura: arritmia, onda bisferiens de pico sistólico, baixa velocidade de pico sistólico, pulsatilidade em veias femorais, bradicardia, taquicardia, onda de pulso parvus tardus e onda de pulso alternans. Houve baixa concordância entre a presença e a não presença de alterações na UV e na avaliação cardiológica. Na análise específica das alterações, os exames tiveram uma concordância variável, que foi boa para o achado de taquicardia, moderada para arritmia e baixa para bradicardia. Não houve concordância entre a UV e os exames cardiológicos para as demais alterações. Conclusões É possível identificar determinadas alterações cardíacas em idosos por meio da análise do formato das ondas periféricas da UV. É importante reconhecer e relatar a presença dessas alterações, pela possibilidade de alertar para um diagnóstico ainda não identificado nesses pacientes. Entretanto, mais estudos são necessários para que seja definida a importância das alterações no formato das ondas Doppler periféricas no reconhecimento de cardiopatias.

  9. Diario de un taller de humor gráfico e historieta costumbrista

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    Entrialgo, Mauro

    2011-09-01

    Full Text Available The author of this text gave lessons of graphic humour and comics dealing with local customs, in the classrooms at the Círculo de Bellas Artes in Madrid during a week in the 2010 summer. His report about these days shows a way to consider the teaching of the comic that places the information about the media and its own narrative tools in close-up and then, the mere plastic accuracy. This way of teaching also proposes specific exercises and alternation of new and traditional technologies. Giving the creative historical precedents and the sector publishing reality, is also a matter of importance from a professional point of view. At the same time, the author explains his theory on the humouristic speech, some considerations about the nature of the drawing and championed a very large definition of the two words: “cartoon story”.

    El autor de este texto impartió un taller de humor gráfico e historieta costumbrista en las aulas del madrileño Círculo de Bellas Artes durante una semana del verano de 2010. Su relato de aquellos días esboza una forma de abordar la enseñanza de la historieta que coloca en primer término el conocimiento del medio y sus herramientas narrativas sobre la mera habilidad plástica. En esa dirección, propone ejercicios concretos y procedimientos que alternan nuevas y tradicionales tecnologías. También destaca la importancia formativa de dar a conocer los antecedentes creativos históricos del medio y la realidad editorial del sector desde el punto de vista profesional, al mismo tiempo que expone fugazmente su particular teoría sobre la estructura del discurso humorístico, emite diversas consideraciones sobre la naturaleza del dibujo y aboga por una amplísima definición del término historieta.

  10. 4 Obras de Welton Becket – (EE. UU.

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    Editorial, Equipo

    1975-07-01

    Full Text Available The four works described in this article are: Citizen's Plaza, Lumbermens Mutual Casualty Company, the Northrop Building and Park Plaza. The three first buildings are entirely designed for offices whereas the last one is a commercial complex that includes two big department stores. Although different in shape and architectonic characteristics all these have a number of common factors, among which the most outstanding ones are: the concrete construction and tüe facades of prefabricated panels with alternative use of concrete and glass; the adaptation of the inner sections to subsequent reorganisations, either by using predetermined modules for the installations or by using mobile partitions; its functional ism, by means of the perfect adequacy of the spaces for their given functions; the creation of pleasant rooms by using to as great an extent as possible naturally beautiful materials both with regard to the structural parts as well as to the surfacing; and finally the integration of the inner space with the outside ttirough large windows. Each construction is completed with parking places, gardens and a great variety of services for the needs of the building.Las cuatro obras que se describen en este artículo son: el Citizens Plaza, el Lumbermens Mutual Casualty Company, el Northrop Building y el Park Plaza. Los tres primeros son edificios destinados en su totalidad a oficinas, mientras que el último es un complejo comercial que incluye dos grandes almacenes. Todos ellos, aunque distintos por su forma y características arquitectónicas, presentan una serie de factores comunes, entre los que destacan: su construcción, a base de estructura de hormigón y fachadas de paneles prefabricados en los que alternan el hormigón y el vidrio; la adaptabilidad de los interiores para sucesivas reorganizaciones, bien por el empleo de módulos predeterminados para las instalaciones, o por la utilización de particiones móviles; su funcionalidad

  11. Alpha B-crystallin prevents the arrhythmogenic effects of particulate matter isolated from ambient air by attenuating oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyelim [The Division of Cardiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University, Seoul (Korea, Republic of); Park, Sanghoon; Jeon, Hyunju [The Division of Cardiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Song, Byeong-Wook [The Division of Cardiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University, Seoul (Korea, Republic of); Kim, Jin-Bae [Division of Cardiology, Kyung Hee University College of Medicine, Seoul (Korea, Republic of); Kim, Chang-Soo [The Department of Preventive Medicine, Yonsei University College of Medicine, Seoul (Korea, Republic of); Pak, Hui-Nam [The Division of Cardiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Hwang, Ki-Chul [The Division of Cardiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University, Seoul (Korea, Republic of); Lee, Moon-Hyoung [The Division of Cardiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Chung, Ji Hyung, E-mail: jhchung@yuhs.ac [The Division of Cardiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Joung, Boyoung, E-mail: cby6908@yuhs.ac [The Division of Cardiology, Yonsei University College of Medicine, Seoul (Korea, Republic of); Brain Korea 21 Project for Medical Science, Yonsei University, Seoul (Korea, Republic of)

    2013-01-15

    Ca{sup 2+}/calmodulin-dependent protein kinase II (CaMKII) is activated by particulate matter (PM) isolated from ambient air and linked to prolonged repolarization and cardiac arrhythmia. We evaluated whether alpha B-crystallin (CryAB), a heat shock protein, could prevent the arrhythmogenic effects of PM by preventing CaMKII activation. CryAB was delivered into cardiac cells using a TAT-protein transduction domain (TAT-CryAB). ECGs were measured before and after tracheal exposure of diesel exhaust particles (DEP) and each intervention in adult Sprague–Dawley rats. After endotracheal exposure of DEP (200 μg/mL for 30 minutes, n = 11), QT intervals were prolonged from 115 ± 14 ms to 144 ± 20 ms (p = 0.03), and premature ventricular contractions were observed more frequently (0% vs. 44%) than control (n = 5) and TAT-Cry (n = 5). However, DEP-induced arrhythmia was not observed in TAT-CryAB (1 mg/kg) pretreated rats (n = 5). In optical mapping of Langendorff-perfused rat heats, compared with baseline, DEP infusion of 12.5 μg/mL (n = 12) increased apicobasal action potential duration (APD) differences from 2 ± 6 ms to 36 ± 15 ms (p < 0.001), APD restitution slope from 0.26 ± 0.07 to 1.19 ± 0.11 (p < 0.001) and ventricular tachycardia (VT) from 0% to 75% (p < 0.001). DEP infusion easily induced spatially discordant alternans. However, the effects of DEP were prevented by TAT-CryAB (1 mg/kg, n = 9). In rat myocytes, while DEP increased reactive oxygen species (ROS) generation and phosphated CaMKII, TAT-CryAB prevented these effects. In conclusion, CryAB, a small heat shock protein, might prevent the arrhythmogenic effects of PM by attenuating ROS generation and CaMKII activation. -- Highlights: ► Particulate matter (PM) increases arrhythmia. ► PM induced arrhythmias are related with oxidative stress and CaMKII activation. ► Alpha B-crystallin (CryAB) could attenuate the arrhythmogenic effect of PM. ► CryAB decreases oxidative stress and CaMKII activation

  12. Spatiotemporal representation of cardiac vectorcardiogram (VCG signals

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    Yang Hui

    2012-03-01

    Full Text Available Abstract Background Vectorcardiogram (VCG signals monitor both spatial and temporal cardiac electrical activities along three orthogonal planes of the body. However, the absence of spatiotemporal resolution in conventional VCG representations is a major impediment for medical interpretation and clinical usage of VCG. This is especially so because time-domain features of 12-lead ECG, instead of both spatial and temporal characteristics of VCG, are widely used for the automatic assessment of cardiac pathological patterns. Materials and methods We present a novel representation approach that captures critical spatiotemporal heart dynamics by displaying the real time motion of VCG cardiac vectors in a 3D space. Such a dynamic display can also be realized with only one lead ECG signal (e.g., ambulatory ECG through an alternative lag-reconstructed ECG representation from nonlinear dynamics principles. Furthermore, the trajectories are color coded with additional dynamical properties of space-time VCG signals, e.g., the curvature, speed, octant and phase angles to enhance the information visibility. Results In this investigation, spatiotemporal VCG signal representation is used to characterize various spatiotemporal pathological patterns for healthy control (HC, myocardial infarction (MI, atrial fibrillation (AF and bundle branch block (BBB. The proposed color coding scheme revealed that the spatial locations of the peak of T waves are in the Octant 6 for the majority (i.e., 74 out of 80 of healthy recordings in the PhysioNet PTB database. In contrast, the peak of T waves from 31.79% (117/368 of MI subjects are found to remain in Octant 6 and the rest (68.21% spread over all other octants. The spatiotemporal VCG signal representation is shown to capture the same important heart characteristics as the 12-lead ECG plots and more. Conclusions Spatiotemporal VCG signal representation is shown to facilitate the characterization of space-time cardiac

  13. Electrocardiographic reference values and configuration of electrocardiogram waves recorded in Black Bengal goats of different age groups.

    Science.gov (United States)

    Pradhan, Ranjeeta Rashmee; Mahapatra, Ambika Prasad Khadanga; Mohapatra, Swagat; Jyotiranjan, Tushar; Kundu, Akshaya Kumar

    2017-09-01

    A study on age-related electrocardiographic (ECG) changes was conducted on 20 apparently healthy Black Bengal goats with no history of cardiac disorders during 2015-2016. The goats selected for the study belonged to four different age groups; Group 1: Goats up to 6 months of age, Group 2: Above 6 months and below 1 year of age, Group 3: Above 1 year and below 2 years of age, and Group 4: Above 2 years of age. The ECG was recorded with the animals in standing position using a 12-lead standard ECG recorder (Model-Cardiart-108 MK VII, manufactured by BPL, India). The paper speed was set to 25 mm/s with the sensitivity of the machine was adjusted at 1 (1 cm=mV). The ECG parameters were compared within different age groups, and the data were analyzed statistically using SPSS 16.0 taking a significant level of 95% (page groups. In bipolar limb lead-II, the amplitude of T-wave, RR interval, ST segment, TP segment, and heart rate was a significant difference among some age groups. Lead-III presented significant difference among age groups in different parameters such as QRS complex duration, T-wave duration, RR interval, ST segment, TP segment, and heart rate. The study concluded that there is a significant variation in the ECG parameters both in terms of values and configuration of ECG waves when age is taken into consideration. The results of the study might be used as a reference value for field veterinarians.

  14. Treadmill exercise testing of asymptomatic men and women without evidence of heart disease

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    W.A. Chalela

    2009-12-01

    Full Text Available The aim of this study was to test the hypothesis of differences in performance including differences in ST-T wave changes between healthy men and women submitted to an exercise stress test. Two hundred (45.4% men and 241 (54.6% women (mean age: 38.7 ± 11.0 years were submitted to an exercise stress test. Physiologic and electrocardiographic variables were compared by the Student t-test and the chi-square test. To test the hypothesis of differences in ST-segment changes, data were ranked with functional models based on weighted least squares. To evaluate the influence of gender and age on the diagnosis of ST-segment abnormality, a logistic model was adjusted; P < 0.05 was considered to be significant. Rate-pressure product, duration of exercise and estimated functional capacity were higher in men (P < 0.05. Sixteen (6.7% women and 9 (4.5% men demonstrated ST-segment upslope ≥0.15 mV or downslope ≥0.10 mV; the difference was not statistically significant. Age increase of one year added 4% to the chance of upsloping of segment ST ≥0.15 mV or downsloping of segment ST ≥0.1 mV (P = 0.03; risk ratio = 1.040, 95% confidence interval (CI = 1.002-1.080. Heart rate recovery was higher in women (P < 0.05. The chance of women showing an increase of systolic blood pressure ≤30 mmHg was 85% higher (P = 0.01; risk ratio = 1.85, 95%CI = 1.1-3.05. No significant difference in the frequency of ST-T wave changes was observed between men and women. Other differences may be related to different physical conditioning.

  15. Dependency of magnetocardiographically determined fetal cardiac time intervals on gestational age, gender and postnatal biometrics in healthy pregnancies

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    Geue Daniel

    2004-04-01

    Full Text Available Abstract Background Magnetocardiography enables the precise determination of fetal cardiac time intervals (CTI as early as the second trimester of pregnancy. It has been shown that fetal CTI change in course of gestation. The aim of this work was to investigate the dependency of fetal CTI on gestational age, gender and postnatal biometric data in a substantial sample of subjects during normal pregnancy. Methods A total of 230 fetal magnetocardiograms were obtained in 47 healthy fetuses between the 15th and 42nd week of gestation. In each recording, after subtraction of the maternal cardiac artifact and the identification of fetal beats, fetal PQRST courses were signal averaged. On the basis of therein detected wave onsets and ends, the following CTI were determined: P wave, PR interval, PQ interval, QRS complex, ST segment, T wave, QT and QTc interval. Using regression analysis, the dependency of the CTI were examined with respect to gestational age, gender and postnatal biometric data. Results Atrioventricular conduction and ventricular depolarization times could be determined dependably whereas the T wave was often difficult to detect. Linear and nonlinear regression analysis established strong dependency on age for the P wave and QRS complex (r2 = 0.67, p r2 = 0.66, p r2 = 0.21, p r2 = 0.13, p st week onward (p Conclusion We conclude that 1 from approximately the 18th week to term, fetal CTI which quantify depolarization times can be reliably determined using magnetocardiography, 2 the P wave and QRS complex duration show a high dependency on age which to a large part reflects fetal growth and 3 fetal gender plays a role in QRS complex duration in the third trimester. Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation.

  16. Exercise induced ST elevation and residual myocardial ischemia in previous myocardial infarction

    International Nuclear Information System (INIS)

    Shimonagata, Tsuyoshi; Nishimura, Tsunehiko; Uehara, Toshiisa; Hayashida, Kohei; Saito, Muneyasu; Sumiyoshi, Tetsuya

    1987-01-01

    The purpose of this study was to evaluate the clinical significance of stress induced ST elevation on infarcted area in 65 patients with previous myocardial infarction (single vessel disease) who had stress thallium scan. Stress induced ST changes on infarcted area were compared with quantitative assessment of myocardial ischemia (thallium ischemic score; TIS) and extent of myocardial infarction (defect score; DS) derived from circumferential profile analysis. In patients with previous myocardial infarction in less than 3 month from the onset (n = 36), left ventricular ejection fraction (LVEF) and extent of abnormal LV wall motion were not significantly different between patients with stress induced ST elevation ( ≥ 2 mm, n = 26) and those with stress induced ST elevation ( < 2 mm, n = 10), while, in patients with previous myocardial infarction in more than 3 month (n = 29), patients with stress induced ST elevation ( ≥ 2 mm, n = 15) showed left ventricular dyskinesis more frequently than those with ST elevation ( < 2 mm, n = 14). In addition, the former showed significantly higher DS and significantly lower TIS than the latter. In patients with previous myocardial infarction in less than 3 month, patients with ST elevation ( ≥ 2 mm, n = 15) with prominent upright T wave (n = 15) had transient thallium defect in infarcted area in 73 % and they had significantly higher LVEF and TIS than those with ST elevation ( < 2 mm, n = 11). These results indicated that ST elevation in infarcted area reflect different significance according to the recovery of injured myocardium and stress induced ST elevation with prominent upright T wave in infarcted area reflect residual myocardial ischemia in less than 3 month from the onset of myocardial infarction. (author)

  17. How the knowledge of genetic "makeup" and cellular data can affect the analysis of repolarization in surface electrocardiogram.

    Science.gov (United States)

    Shimizu, Wataru

    2010-01-01

    This review article sought to describe patterns of repolarization on the surface electrocardiogram in inherited cardiac arrhythmias and to discuss how the knowledge of genetic makeup and cellular data can affect the analysis based on the data derived from the experimental studies using arterially perfused canine ventricular wedge preparations. Molecular genetic studies have established a link between a number of inherited cardiac arrhythmia syndromes and mutations in genes encoding cardiac ion channels or membrane components during the past 2 decades. Twelve forms of congenital long QT syndrome have been so far identified, and genotype-phenotype correlations have been investigated especially in the 3 major genotypes-LQT1, LQT2, and LQT3. Abnormal T waves are reported in the LQT1, LQT2, and LQT3, and the differences in the time course of repolarization of the epicardial, midmyocardial, and endocardial cells give rise to voltage gradients responsible for the manifestation of phenotypic appearance of abnormal T waves. Brugada syndrome is characterized by ST-segment elevation in leads V1 to V3 and an episode of ventricular fibrillation, in which 7 genotypes have been reported. An intrinsically prominent transient outward current (I(to))-mediated action potential notch and a subsequent loss of action potential dome in the epicardium, but not in the endocardium of the right ventricular outflow tract, give rise to a transmural voltage gradient, resulting in ST-segment elevation, and a subsequent phase 2 reentry-induced ventricular fibrillation. In conclusion, transmural electrical heterogeneity of repolarization across the ventricular wall profoundly affects the phenotypic manifestation of repolarization patterns on the surface electrocardiogram in inherited cardiac arrhythmias. Copyright © 2010 Elsevier Inc. All rights reserved.

  18. Sress cardiomyopathy: clinical features and imaging findings

    International Nuclear Information System (INIS)

    Zhao Shihua; Yan Chaowu; Jiang Shiliang; Lu Minjie; Li Shiguo; Liu Qiong; He Zuoxiang

    2007-01-01

    Objective: One typical case with stress cardiomyopathy was reported and the current knowledge of the syndrome was reviewed to improve relevant knowledge. Methods: A 71-year-old female patient presented dyspnea and chest pain due to emotional stress. ECG, echocardiography, selective coronary, artery angiography, left ventriculography, 99 Tc m -MIBI single photon emission computed tomography (SPECT), 18 F-FDG SPECT and MRI were performed. Results: Electrocardiogram at admission showed ST segment elevation and T wave inversion in leads V1-V4. Pathological Q wave occurred 1 week later, it disappeared 1 month later however and severe T wave inversion occurred. Normal or slightly elevated cardiac enzymes in the blood were found during the course. Left ventriculogram at admission showed left ventricular apical ballooning with LVEF of 30%. The ballooning volume was about 3/4 of left ventricular volume, without any corresponding coronary artery diseases found in coronary angiogram. The abnormal apical ballooning decreased significantly in the follow-up left ventficulogram performed one month later. The LVEF rose up to 63.6%. 99 Tc m -MIBI and 18 F-FDG SPECT showed mismatch of perfusion and metabolism in the corresponding region, indicating presence of viable myocardium. MRI showed left ventricular apical ballooning without perfusion defect and late enhancement, indicating viability of corresponding myocardium. Conclusions: Emotional stress can cause transient left ventricular apical ballooning called 'stress cardiomyopathy'. Either 99 Tc m -MIBI SPECT associated with 18 F-FDG SPECT or delayed enhancement MRI plays an important role in identification of myocardial viability, which can efficiently guide clinical treatment. (authors)

  19. Pseudo-real-time low-pass filter in ECG, self-adjustable to the frequency spectra of the waves.

    Science.gov (United States)

    Christov, Ivaylo; Neycheva, Tatyana; Schmid, Ramun; Stoyanov, Todor; Abächerli, Roger

    2017-09-01

    The electrocardiogram (ECG) acquisition is often accompanied by high-frequency electromyographic (EMG) noise. The noise is difficult to be filtered, due to considerable overlapping of its frequency spectrum to the frequency spectrum of the ECG. Today, filters must conform to the new guidelines (2007) for low-pass filtering in ECG with cutoffs of 150 Hz for adolescents and adults, and to 250 Hz for children. We are suggesting a pseudo-real-time low-pass filter, self-adjustable to the frequency spectra of the ECG waves. The filter is based on the approximation procedure of Savitzky-Golay with dynamic change in the cutoff frequency. The filter is implemented pseudo-real-time (real-time with a certain delay). An additional option is the automatic on/off triggering, depending on the presence/absence of EMG noise. The analysis of the proposed filter shows that the low-frequency components of the ECG (low-power P- and T-waves, PQ-, ST- and TP-segments) are filtered with a cutoff of 14 Hz, the high-power P- and T-waves are filtered with a cutoff frequency in the range of 20-30 Hz, and the high-frequency QRS complexes are filtered with cutoff frequency of higher than 100 Hz. The suggested dynamic filter satisfies the conflicting requirements for a strong suppression of EMG noise and at the same time a maximal preservation of the ECG high-frequency components.

  20. Stable gastric pentadecapeptide BPC 157 and bupivacaine.

    Science.gov (United States)

    Zivanovic-Posilovic, Gordana; Balenovic, Diana; Barisic, Ivan; Strinic, Dean; Stambolija, Vasilije; Udovicic, Mario; Uzun, Sandra; Drmic, Domagoj; Vlainic, Josipa; Bencic, Martina Lovric; Sindic, Aleksandra; Seiwerth, Sven; Sikiric, Predrag

    2016-12-15

    Bupivacaine toxicity following accidental overdose still lacks therapeutic solution. However, there are major arguments for testing BPC 157 against bupivacaine toxicity in vivo in rats, in particular, and then finally, in vitro. These are: the lack of any known BPC 157 toxicity, a lifesaving effect via the mitigation of arrhythmias in rats underwent hyperkalemia or digitalis toxicity, the elimination of hyperkalemia and arrhythmias in rats underwent succinylcholine toxicity and finally, the reduction of potassium-induced depolarization in vitro (in HEK293 cells) in severe hyperkalemia. Most importantly, BPC 157 successfully prevents and counteracts bupivacaine cardiotoxicity; BPC 157 is effective even against the worst outcomes such as a severely prolonged QRS complex. Here, rats injected with bupivacaine (100mg/kg IP) exhibited bradycardia, AV-block, ventricular ectopies, ventricular tachycardia, T-wave elevation and asystole. All of the fatalities had developed T-wave elevation, high-degree AV-block, respiratory arrest and asystole. These were largely counteracted by BPC 157 administration (50µg/kg, 10µg/kg, 10ng/kg, or 10pg/kg IP) given 30min before or 1min after the bupivacaine injection. When BPC 157 was given 6min after bupivacaine administration, and after the development of prolonged QRS intervals (20ms), the fatal outcome was markedly postponed. Additionally, the effect of bupivacaine on cell membrane depolarization was explored by measuring membrane voltages (Vm) in HEK293 cells. Bupivacaine (1mM) alone caused depolarization of the cells, while in combination with BPC 157 (1µm), the bupivacaine-induced depolarization was inhibited. Together, these findings suggest that the stable gastric pentadecapeptide BPC 157 should be a potential antidote for bupivacaine cardiotoxicity. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Electrocardiographic parameters of the American Miniature Horse: influence of age and sex

    Directory of Open Access Journals (Sweden)

    Bianca P. Santarosa

    2016-06-01

    Full Text Available Abstract: The veterinary cardiology has growing importance in equine medicine. There are studies of standardization of electrocardiographic parameters of many races, according to their stature and ability. However, no studies are in the literature with the American Miniature Horse. To evaluate the electrocardiogram (ECG tracing configuration of this breed at rest and to verify the influence of age and sex on ECG parameters, 203 horses including 143 females and 60 males were divided into four age groups (foals, yearlings, adults and elderly. Electrocardiographic parameters were performed by computerized electrocardiogram (TEB, and the parameters were evaluated in six leads of frontal plane (Lead I, II, III, aVR, aVL and aVF and base-apex (BA. Heart rates (HR decreased with increasing age were higher in males than in females. Sinus tachycardia followed by sinus arrhythmia was dominant in both sexes. The cardiac axis was higher in males and ranged between 120° and 150° for foals, 30° and 60° for yearlings and adults, and 60° and 90° for the elderly. The P wave was bifid in several animals. The P-wave amplitude and T-wave duration from lead II and BA were larger in males than in females. The majority of the animals exhibited ST segment depression and a negative T-wave. The most common QRS complex morphology was Qr. Differences were observed between the electrocardiographic tracings of males and females, and age influenced the ECG parameters. Therefore, this study established the ECG patterns for the American Miniature Horse breed and could be used to determine the influence of age and sex on several of the studied variables.

  2. Resting 12-lead electrocardiogram reveals high-risk sources of cardioembolism in young adult ischemic stroke.

    Science.gov (United States)

    Pirinen, Jani; Putaala, Jukka; Aro, Aapo L; Surakka, Ida; Haapaniemi, Anita; Kaste, Markku; Haapaniemi, Elena; Tatlisumak, Turgut; Lehto, Mika

    2015-11-01

    The diagnostic work-up to reveal etiology in a young ischemic stroke (IS) patient includes evaluation for high-risk source of cardioembolism (HRCE), since this subtype associates with high early recurrence rate and mortality. We investigated the association of ECG findings with a final etiologic subgroup of HRCE in a cohort of young patients with first-ever IS. The Helsinki Young Stroke Registry includes IS patients aged 15 to 49 years admitted between 1994 and 2007. Blinded to other clinical data, we analyzed a 12-lead resting ECG obtained 1-14 days after the onset of stroke symptoms in 690 patients. We then compared the ECG findings between a final diagnosis of HRCE (n=78) and other/undetermined causes (n=612). We used multivariate logistic regression to study the association between ECG parameters and HRCE. Of our cohort (63% male), 35% showed ECG abnormality, the most common being T-wave inversion (16%), left ventricular hypertrophy (14%), prolonged P-wave (13%), and prolonged QTc (12%). 3% had atrial fibrillation (AF), and 4% P-terminal force (PTF). Of the continuous parameters, longer QRS-duration, QTc, and wider QRS-T-angle independently associated with HRCE. After AF, PTF had the strongest independent association with HRCE (odds ratio=44.32, 95% confidence interval=[10.51-186.83]), followed by a QRS-T angle >110° (8.29 [3.55-19.32]), T-wave inversion (5.06, 2.54-10.05), and prolonged QTc (3.02 [1.39-6.56]). Routine ECG provides useful information for directing the work-up of a young IS patient. In addition to AF, PTF in particular showed a strong association with etiology of HRCE. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. A wavelet-based ECG delineation algorithm for 32-bit integer online processing.

    Science.gov (United States)

    Di Marco, Luigi Y; Chiari, Lorenzo

    2011-04-03

    Since the first well-known electrocardiogram (ECG) delineator based on Wavelet Transform (WT) presented by Li et al. in 1995, a significant research effort has been devoted to the exploitation of this promising method. Its ability to reliably delineate the major waveform components (mono- or bi-phasic P wave, QRS, and mono- or bi-phasic T wave) would make it a suitable candidate for efficient online processing of ambulatory ECG signals. Unfortunately, previous implementations of this method adopt non-linear operators such as root mean square (RMS) or floating point algebra, which are computationally demanding. This paper presents a 32-bit integer, linear algebra advanced approach to online QRS detection and P-QRS-T waves delineation of a single lead ECG signal, based on WT. The QRS detector performance was validated on the MIT-BIH Arrhythmia Database (sensitivity Se = 99.77%, positive predictive value P+ = 99.86%, on 109010 annotated beats) and on the European ST-T Database (Se = 99.81%, P+ = 99.56%, on 788050 annotated beats). The ECG delineator was validated on the QT Database, showing a mean error between manual and automatic annotation below 1.5 samples for all fiducial points: P-onset, P-peak, P-offset, QRS-onset, QRS-offset, T-peak, T-offset, and a mean standard deviation comparable to other established methods. The proposed algorithm exhibits reliable QRS detection as well as accurate ECG delineation, in spite of a simple structure built on integer linear algebra.

  4. Differential diagnosis between early repolarization of athlete's heart and coved-type Brugada electrocardiogram.

    Science.gov (United States)

    Zorzi, Alessandro; Leoni, Loira; Di Paolo, Fernando M; Rigato, Ilaria; Migliore, Federico; Bauce, Barbara; Pelliccia, Antonio; Corrado, Domenico

    2015-02-15

    Early repolarization (ER) is typically observed in highly trained athletes as a physiologic consequence of increased vagal tone. The variant of anterior (V1 to V3) ER characterized by "domed" ST-segment elevation and negative T wave raises problems of differential diagnosis with the "coved-type" electrocardiographic pattern seen in Brugada syndrome (BS). This study was designed to identify electrocardiographic criteria for distinguishing athlete's ER from BS. The study compared the electrocardiographic tracings of 61 healthy athletes (80% men, median age 23 ± 8 years), showing "domed" ST-segment elevation and negative T wave in leads V1 to V3, with those of 92 consecutive age- and sex-matched BS patients with a "coved-type" electrocardiographic pattern. The electrocardiographic analysis focused on the ST-segment elevation at J point (STJ) and at 80 milliseconds after J point (ST₈₀). Athletes had a lower maximum amplitude of STJ (1.46 ± 0.7 vs 3.25 ± 0.6 mm, p 1) versus only 2 (3%) athletes (p <0.001). An upsloping ST-segment configuration (STJ/ST₈₀ <1) showed a sensitivity of 97%, a specificity of 100%, and a diagnostic accuracy of 98.7% for the diagnosis of ER. At multivariate analysis, STJ/ST₈₀ ratio remained the only independent predictor for ER (odds ratio 87, 95% confidence interval 19 to 357, p <0.001). In conclusion, the STJ/ST₈₀ ratio is a highly accurate electrocardiographic parameter for differential diagnosis between anterior ER of the athlete and BS. Our results may help in reducing the number of athletes who undergo expensive diagnostic workup or are unnecessarily disqualified from competition for changes that fall within the normal range of athlete's heart. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Cadmium stress assessment based on the electrocardiogram characteristics of zebra fish (Danio rerio): QRS complex could play an important role.

    Science.gov (United States)

    Xing, Na; Ji, Lizhen; Song, Jie; Ma, Jingchun; Li, Shangge; Ren, Zongming; Xu, Fei; Zhu, Jianping

    2017-10-01

    The electrocardiogram (ECG) of zebra fish (Danio rerio) expresses cardiac features that are similar to humans. Here we use sharp microelectrode measurements to obtain ECG characteristics in adult zebra fish and analyze the effects of cadmium chloride (CdCl 2 ) on the heart. We observe the overall changes of ECG parameters in different treatments (0.1 TU, 0.5 TU and 1.0 TU CdCl 2 ), including P wave, Q wave, R wave, S wave, T wave, PR interval (atrial contraction), QRS complex (ventricular depolarization), ST segment, and QT interval (ventricular repolarization). The trends of the ECG parameters showed some responses to the concentration and exposure time of CdCl 2 , but it was difficult to obtain more information about the useful indicators in water quality assessment depending on tendency analysis alone. A self-organizing map (SOM) showed that P values, R values, and T values were similar; R wave and T wave amplitude were similar; and most important, QRS value was similar to the CdCl 2 stress according to the classified data patterns including CdCl 2 stress (E) and ECG components based on the Ward linkage. It suggested that the duration of QRS complex was related to environmental stress E directly. The specification and evaluation of ECG parameters in Cd 2+ pollution suggested that there is a markedly significant correlation between QRS complex and CdCl 2 stress with the highest r (0.729) and the smallest p (0.002) among all ECG characteristics. In this case, it is concluded that QRS complex can be used as an indicator in the CdCl 2 stress assessment due to the lowest AIC data abased on the linear regression model between the CdCl 2 stress and ECG parameters. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Arrhythmogenic right ventricular dysplasia: Atypical clinical presentation.

    Science.gov (United States)

    Marçalo, José; Menezes Falcão, Luiz

    2017-03-01

    A 67-year-old man was admitted to our hospital after episodes of syncope preceded by malaise and diffuse neck and chest discomfort. No family history of cardiac disease was reported. Laboratory workup was within normal limits, including D-dimers, serum troponin I and arterial blood gases. The electrocardiogram showed sinus rhythm with T-wave inversion in leads V1 to V3. Computed tomography angiography to investigate pulmonary embolism showed no abnormal findings. Transthoracic echocardiography (TTE) displayed massive enlargement of the right ventricle with intact interatrial septum and no pulmonary hypertension. Cardiac magnetic resonance imaging (MRI) confirmed right ventricular (RV) dilatation and revealed marked hypokinesia/akinesia of the lateral wall. Exercise stress testing was negative for ischemia. According to the 2010 Task Force criteria for arrhythmogenic right ventricular dysplasia (ARVD), this patient presented two major criteria (global or regional dysfunction and structural alterations: by MRI, regional RV akinesia or dyskinesia or dyssynchronous RV contraction and RV ejection fraction ≤40%, and repolarization abnormalities: inverted T waves in right precordial leads [V1, V2, and V3]); and one minor criterion (>500 ventricular extrasystoles per 24 hours by Holter), and so a diagnosis of ARVD was made. After electrophysiologic study (EPS) the patient received an implantable cardioverter-defibrillator (ICD). This late clinical presentation of ARVD highlights the importance of TTE screening, possibly complemented by MRI. The associated risk of sudden death was assessed by EPS leading to the implantation of an ICD. Genetic association studies should be offered to the offspring of all ARVD patients. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  7. Long-term single-center experience of defibrillator therapy in children and adolescents.

    Science.gov (United States)

    Frommeyer, Gerrit; Feder, Sebastian; Bettin, Markus; Debus, Volker; Köbe, Julia; Reinke, Florian; Uebing, Anselm; Eckardt, Lars; Kehl, Hans Gerd

    2018-06-01

    Implantable cardioverter-defibrillator (ICD) systems are established therapy for prevention of sudden cardiac death. Long-term data on ICD systems in children and adolescents is rare. The present study displays a long-term single-center follow-up of children and adolescents with ICD systems. The present study represents a single-center experience of patients younger than 18 years who received an ICD (n = 58). Follow-up data included in-house follow-up as well as examinations of collaborating specialists. Mean age at implantation was 14.0 ± 3.3 years and 33 patients (56.9%) were male. A transvenous ICD system was implanted in 54 patients (93.1%). In 33 patients (56.9%) electrical heart disease or idiopathic ventricular fibrillation represented the underlying condition of ICD implantation. Median follow-up duration was 70 months (45; 94). 3 patients (5.2%) died during the observation period. None of these deaths was associated with ICD failure. Appropriate shocks occurred in 32 patients (55.2%). Inappropriate shock delivery was recorded in 17 patients (29.3%). Supraventricular tachycardia represented the most frequent cause of inappropriate shock delivery (9 patients, 52.9%). T-wave oversensing led to inappropriate shock delivery in 3 patients (17.6%). In 5 patients (29.4%), lead failure caused inappropriate shock delivery. Of note, during follow-up lead failure was reported in 15 patients (25.9%) leading to surgical revision. ICD therapy in children and adolescents is effective for prevention of sudden cardiac death. The rate of appropriate shock deliveries was significantly higher as compared with large ICD trials. Inappropriate therapies occurred frequently. In particular supraventricular tachycardia, T-wave oversensing and lead failures were responsible for these episodes. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. [The influence of occupational lead exposure on transmural repolarization dispersion].

    Science.gov (United States)

    Zyśko, Dorota; Gajek, Jacek; Chlebda, Ewa; Mazurek, Walentyna

    2005-02-01

    The parts of QT interval: time from Q wave to the peak of T wave (QTp) representing the de- and repolarization of subepicardial layer and the time from the peak of T wave to its end (QTp-e) building the transmural dispersion of repolarization enable more exact assessment of repolarization period of the heart muscle. Occupational exposure to lead influences the electrophysiologic properties of the heart. The aim of our study was to assess the QTp and QTp-e interval in workers occupationally exposed to lead. The study was carried out in 22 copper smelters aged 41.8 +/- 8.7 years, occupationally exposed to lead. The control group consisted of 14 healthy men. In all studied subjects blood lead concentration (Pb) and the concentration of free protoporphyrins in erytrocytes were assessed. 24-hour ECG holter monitoring was done to study rhythm disturbances and the duration in lead CM5 of QT interval, QTp interval, RR interval preceding the assessed QT interval (pRR) during sleep, rest during the awake state and moderate daily activity. The QTp-e interval is the difference between the duration of QT and QTp interval. The duration of QTp and QTp-e in occupationally exposed workers and healthy persons did not differ significantly. These parameters were significantly lower in both groups during moderately physical activity comparing to the values during sleep. The QTp-e/ QTp ratio in occupationally exposed workers during night hours was significantly lower than during daily activity what was not the case in control persons. Occupational exposure to lead do not change significantly the transmural dispersion of repolarization. Occupational exposure to lead diminishes the QTp-e/QTp ratio during the night.

  9. Detection of Acute Myocardial Infarction in a Pig Model Using the SAN-Atrial-AVN-His (SAAH) Electrocardiogram (ECG), Model PHS-A10, an Automated and Integrated Signals Recognition System.

    Science.gov (United States)

    Zhao, Wenjiao; Lu, Guihua; Liu, Li; Sun, Zhishan; Wu, Mingxin; Yi, Wenyan; Chen, Haiyan; Li, Yanhui; Tang, Lilong; Zeng, Jianping

    2018-03-04

    BACKGROUND The aim of this study was to compare the use of the standard 12-lead electrocardiogram (ECG) with the SAN-Atrial-AVN-His (SAAH) ECG (Model PHS-A10), a new automated and integrated signals recognition system that detects micro-waveforms within the P, QRS, and T-wave, in a pig model of acute myocardial infarction (MI). MATERIAL AND METHODS Six medium-sized domestic Chinese pigs underwent general anesthesia, and an angioplasty balloon was placed and dilated for 120 minutes in the first diagonal coronary artery arising from the left anterior descending (LAD) coronary artery. A standard ECG and a SAAH ECG (Model PHS-A10) were used to evaluate: 1) the number of wavelets in ST-T segment in lead V5; 2) the duration of the repolarization initial (Ri), or duration of the wavelets starting from the J-point to the endpoint of the wavelets in the ST interval; 3) the duration of the repolarization terminal (Rt), of the wavelets, starting from the endpoint of the wavelets in the ST interval to the cross-point of the T-wave and baseline; 4) the ratio Ri: Rt. RESULTS Following coronary artery occlusion, duration of Ri and Ri/Rt increased, and Rt decreased, which was detected by the SAAH ECG (Model PHS-A10) within 12 seconds, compared with standard ECG that detected ST segment depression at 24 seconds following coronary artery occlusion. CONCLUSIONS The findings from this preliminary study in a pig model of acute MI support the need for clinical studies to evaluate the SAAH ECG (Model PHS-A10) for the early detection of acute MI.

  10. Ethnic differences in electrocardiographic amplitude measurements

    International Nuclear Information System (INIS)

    Mansi, Ishak A.; Nash, Ira S.

    2004-01-01

    There is a controversy regarding ethnic differences in electrocardiographic (ECG) patterns because of the potentially confounding socioeconomic, nutritional, environmental and occupational factors. We reviewed the first 1000 medical files of a multiethnic community, where all individuals shared similar living conditions. Only healthy adults age 15 to 60 years were included. Wave amplitudes were measured manually from the standard 12lead ECG. Minnesota coding was used. ECG from 597 subjects were included in the study: 350 Saudi Arabians, 95 Indians, 17 Sri-Lankans, 39 Filipinos, and 57 Caucasians; 349 were men. the mean +-SD of Sokolow-Lyon voltage (SLV) in men was signifcantly different among ethnic groups (2.9+-0.86, 2.64+-0.79, 2.73+-0.72, 3.23+-0.61, 2.94+-0.6, 2.58+-0.79 mV, P=0.0006, for Saudi's, Indians, Jordanians, Filipinos, Sri-Lankans, and Caucasians, respectively). SLV was similar among ethnic groups in women. The prevalence of early transition pattern was also different among ethnic groups in men but not women (15.8%, 34.6%, 17.9%, 21.7%, 35.3%, 26.8% in Suadi, Indian, Jordanian, Filipino, Sri-Lankan, and Caucasian, respectively, P=0.037). T wave amplitude was significantly different among ethnic groups in selected lead. ECG wave amplitude differs with ethnic region even when other factors are similar. Using SLV of 3.5 mV as a criterion may overestimate the incidence of left ventricular hypertrophy in some ethnic groups. The pattern of high R wave in lead V1is common in healthy adults in certain ethnic groups. T wave height differs with ethnic origin and sex. (author)

  11. Electrocardiographic Findings and Serum Troponin I in Carbon Monoxide Poisoned Patients

    Directory of Open Access Journals (Sweden)

    Scott Reza Jafarian Kerman

    2012-03-01

    Full Text Available Carbon monoxide (CO poisoning, though with different sources, is one of the most deadly emergencies in all countries. CO can threaten men's life by several paths especially cardiac complications, which can mimic other cardiac problems such as myocardial infarction. The objective of this study was to determine ECG findings and serum troponin I levels in CO poisoned patients. In this analytical cross-sectional study, 63 CO poisoning patients were consecutively included from hospital's emergency departments. CO content was measured by a CO-oximeter and an electrocardiography was taken first thing on admission. Arterial blood gas (ABG, troponin I and other data was collected afterwards. Data were divided by age groups (adults and children and gender. CO content was significantly higher only in subjects with normal T wave compared to patients with inverted T wave in their initial ECG (P=0.016. No other significant difference was noticed. None of the ABG findings correlated significantly with CO content. Also no significant correlation was found with CO content after stratification by gender and age groups, but pH in children (r=-0.484, P=0.026. CO content was significantly higher in adults (P=0.023, but other ABG data were not significantly different. Only 3 patients had elevated troponin I. Receiver operating characteristic (ROC analysis showed no significant cutoff points in CO content for ECG changes. No significant specific change in electrocardiograms (ECG could contribute carboxyhemoglobin content in carbon monoxide poisoned patients. In addition, no specific difference was found between adults and pediatric subjects' ECGs. All other findings seemed to be accidental.

  12. INTERNATIONAL UNION OF OPERATING ENGINEERS NATIONAL HAZMAT PROGRAM - PORTER-CABLE CIRCULAR SAW OENHP: 2001-04, VERSION A; TOPICAL

    International Nuclear Information System (INIS)

    Unknown

    2002-01-01

    Florida International University's (FIU) Hemispheric Center for Environmental Technology (HCET) evaluated five saws for their effectiveness in cutting specially prepared fiberglass-reinforced plywood crates. These crates were built as surrogates for crates that presently hold radioactively contaminated glove boxes at the Department of Energy's (DOE) Los Alamos facility. The Porter-Cable circular saw was assessed on August 15-16, 2001 (Porter-Cable No.1 and Porter-Cable No.2, respectively). During the FIU test of efficacy, a team from the Operating Engineers National Hazmat Program (OENHP) evaluated the occupational safety and health issues associated with this technology. The Porter-Cable saw is a straightforward machine for cutting wood of varying thickness. The blade is fully guarded with a fixed upper and a lower retractable guard. The lower guard retracts as the blade engages the work piece. The unit is operated with an on/off guarded trigger switch and is supported with a handgrip mounted near the front of the saw. The saw is equipped with a directional nozzle, which aims sawdust away from the operator and the line of cut. An optional vacuum system, attached to the directional nozzle, is used to remove and collect dust. During the demonstration of Porter-Cable No.1, personal noise sampling indicated that one worker was under and one was at the Occupational Safety and Health Administration's (OSHA) Action Level of 85 decibels (dBA) with time-weighted averages (TWA's) of 82.7 and 84.6 dBA, respectively. During the demonstration of Porter-Cable No.2, however, both workers did exceed the Action Level with TWA's of 89.7 and 90.0 dBA. These data are not entirely representative as they were gathered during a simulation and not at the actual worksite. Additional sampling should be conducted on-site, but the workers should wear hearing protection until it is determined that it is no longer necessary. The total nuisance dust sample for Porter-Cable No.1 was 3

  13. [Expression of heat shock protein 70 and its mRNA in career exposure to manganese].

    Science.gov (United States)

    Chen, Wenwen; Shao, Hua; Chi, Mingfeng; Zhang, Zhihu; Shan, Yongle; Zou, Wei

    2015-10-01

    To analyze the expression levels of heat shock protein70 (HSPs70) and HSPs70 mRNA in different exposure to manganese, and research the neuroprotective effect on the career exposure to manganese. From 2008 to 2009, with cross-sectional study design, and in a locomotive and rolling stock works, by stratified random sampling method, the exposed sample consisted of 180 welders from different welding shops and 100 unexposed in the last three years, non-welder controls with age-matched workers of similar socioeconomic status from the same industry. The control workers had not been exposed to neurotoxic chemicals. The mRNA expressions of four different metabolic enzyme were detected by SYBR Green I quantitative real-time polymerase chain reaction. The expression levels of the two enzymes mRNA in different exposure to manganese were analyzed. The expressions of HSPs70 were detected by Western blot. The concentration of air manganese was determined by GFAAS. The average concentration of 8 h time (8h-TWA) was used to express the level of individual exposure to manganese, according to the air manganese workplace occupational exposure limit (8h-TWA=0.15 mg/m3), the exposed group is divided into high exposed group (>0.15 mg/m3) and low exposure group (<0.15 mg/m3). The individuals exposed to manganese dose of exposed group ((0.25±0.31) mg/m3) was higher than the control group ((0.06±0.02) mg/m3) (t=6.15, P=0.001); individuals exposed to manganese dose of high exposure group for (0.42±0.34) mg/m3, which was higher than low exposure group (0.09±0.07) mg/m3 (t=9.80, P=0.001). HSPs70 mRNA and protein of exposure group (5.65±0.21, 3.26±0.15) were higher than the reference group (0.41±0.03, 1.32±0.12) (t=18.91, t=8.68, P=0.001). HSP70 mRNA and protein of high exposure group (6.48±0.37, 3.67±0.26) were higher than the low exposure group (5.15±0.23, 3.02±0.19) (t=3.24, t=2.01, P=0.003, P=0.043). The expression of peripheral blood lymphocytes HSPs70 level and HSPs70 m

  14. Preface

    Science.gov (United States)

    2003-09-01

    stresses, electromagnetic force, and mechanical and thermal cycling. • Mechanical properties: tensile and compressive properties, fatigue characteristics and fracture behaviour. • Thermal properties: thermal conductivity, thermal dilatation and thermal strain. • Modelling: prediction of critical current and mechanical properties of composite superconductors through statistical analysis, finite element analysis, etc. • Test methods: international cooperative research work to establish test methods for assessing mechano-electromagnetic properties based on the activity of VAMAS/TWA-16. This discussion took place with respect to three types of composites: • MFC (multifilamentary composite): BSCCO, MgB2, Nb-Ti, Nb3Sn and Nb3Al. • CCC (coated conductor composite): YBCO and ReBCO. • BCC (bulk crystal composite): YBCO and ReBCO. More than 55 researchers attended the MEM03 workshop, coming from eight different countries. A total of 42 papers were presented. In this special issue of Superconductor Science and Technology selected papers have been included that are concerned with the comprehensive scientific research subjects mentioned above. The aim of this issue is to provide a snapshot of some of the current state-of-the-art research and to promote further research into the mechano-electromagnetic properties of composite superconductors. The workshop was organized under the activities of NEDO technology quest and VAMAS/TWA-16. We wish to thank the following for their contribution to the success of the workshop: NEDO Super-ACE project, AFOSR, AOARD and IEC/TC90-JNC. Guest Editors: Kozo Osamura Hitoshi Wada Arman Nyilas Damian Hampshire

  15. INTERNATIONAL UNION OF OPERATING ENGINEERS NATIONAL HAZMAT PROGRAM - EVOLUTION 180 CIRCULAR SAW OENHP: 2001-03, VERSION A; TOPICAL

    International Nuclear Information System (INIS)

    Unknown

    2002-01-01

    Florida International University's (FIU) Hemispheric Center for Environmental Technology (HCET) evaluated five saws for their effectiveness in cutting specially prepared fiberglass-reinforced plywood crates. These crates were built as surrogates for crates that presently hold radioactively contaminated gloveboxes at the Department of Energy's (DOE) Los Alamos facility. The Evolution 180 circular saw was assessed on August 14, 2001. During the FIU test of efficacy, a team from the Operating Engineers National Hazmat Program (OENHP) evaluated the occupational safety and health issues associated with this technology. The Evolution 180 is a portable, metal cutting circular saw with a 7-inch diameter blade. The blade is contained within the main housing and has a retractable lower blade guard to prevent operator access to the blade during operation and shutdown. The saw is equipped with a chip collector. The maximum cutting thickness for metal is one-quarter inch and can cut steel tubing and pipe 2 inches in diameter. The unit is operated with an on/off guarded trigger switch and is supported with the hand guide mounted to the side of the saw. An adjustable lever sets the depth of the cut. The machine's circuitry will automatically shut the saw motor off if excessive overload is detected during operation. The one-half hour demonstration involved vertical and horizontal cuts and blade changes. During this process, operators experienced binding of the saw. This caused the blade to become hot, causing the sawdust collected in the chip collector to smoke. Care should be exercised to use the appropriate blade for the application, operator training, and personal protective equipment (PPE). Personal noise sampling indicated that neither worker was over the Occupational Safety and Health Administration's (OSHA) Action Level of 85 decibels (dBA) with time-weighted averages (TWA's) of 69.1 and 68.8 dBA. The personal noise sample taken during the special demonstration with the

  16. Comparison of active and passive sampling strategies for the monitoring of pesticide contamination in streams

    Science.gov (United States)

    Assoumani, Azziz; Margoum, Christelle; Guillemain, Céline; Coquery, Marina

    2014-05-01

    The monitoring of water bodies regarding organic contaminants, and the determination of reliable estimates of concentrations are challenging issues, in particular for the implementation of the Water Framework Directive. Several strategies can be applied to collect water samples for the determination of their contamination level. Grab sampling is fast, easy, and requires little logistical and analytical needs in case of low frequency sampling campaigns. However, this technique lacks of representativeness for streams with high variations of contaminant concentrations, such as pesticides in rivers located in small agricultural watersheds. Increasing the representativeness of this sampling strategy implies greater logistical needs and higher analytical costs. Average automated sampling is therefore a solution as it allows, in a single analysis, the determination of more accurate and more relevant estimates of concentrations. Two types of automatic samplings can be performed: time-related sampling allows the assessment of average concentrations, whereas flow-dependent sampling leads to average flux concentrations. However, the purchase and the maintenance of automatic samplers are quite expensive. Passive sampling has recently been developed as an alternative to grab or average automated sampling, to obtain at lower cost, more realistic estimates of the average concentrations of contaminants in streams. These devices allow the passive accumulation of contaminants from large volumes of water, resulting in ultratrace level detection and smoothed integrative sampling over periods ranging from days to weeks. They allow the determination of time-weighted average (TWA) concentrations of the dissolved fraction of target contaminants, but they need to be calibrated in controlled conditions prior to field applications. In other words, the kinetics of the uptake of the target contaminants into the sampler must be studied in order to determine the corresponding sampling rate

  17. An assessment of occupational exposure to polycyclic aromatic hydrocarbons in the UK.

    Science.gov (United States)

    Unwin, John; Cocker, John; Scobbie, Emma; Chambers, Helen

    2006-06-01

    A cross-industry occupational hygiene survey was commissioned by the Health and Safety Executive (HSE) to determine the levels of polycyclic aromatic hydrocarbon (PAH) exposure in UK industry and to determine if one or more target analytes were suitable as markers for assessing total exposure to PAHs. There were no broadly applicable UK exposure standards for assessing total exposure to PAHs. Until 1993 a guidance value for assessing exposure in coke ovens only, where PAH exposure is known to be the highest, was based on gravimetric analysis of cyclohexane-soluble material. Biological monitoring based on urinary 1-hydroxypyrene (1-OHP) is widely reported to be an effective indicator of exposure by both dermal and inhalation routes but there was no UK guidance value. The survey involved an occupational hygiene study of 25 sites using both airborne monitoring of a total of 17 individual PAHs and biological monitoring. The results showed 8 h TWA levels of total PAH in air ranged from 0.4 to 1912.6 microg m(-3) with a GM of 15.8 microg m(-3). The profile of PAHs was dominated by naphthalene, the most volatile 2-ring PAH. Airborne benzo(a)pyrene (BaP) correlated well (r(2) = 0.971) with levels of carcinogenic 4-6 ring PAHs and was an effective marker of exposure for all industries where significant particle bound PAH levels were found and, in particular, for CTPV exposure. The 8 h TWA levels of BaP ranged from <0.01 to 6.21 microg m(-3) with a GM of 0.036 microg m(-3); 90% were <0.75 microg m(-3) and 95% were <2.0 microg m(-3). Two hundred and eighteen urine samples collected from different workers at the end of shift and 213 samples collected pre-shift next day were analysed for 1-OHP. Levels of 1-OHP in end-of-shift samples were generally higher than those in pre-shift-next-day samples and showed a good correlation (r(2) = 0.768) to airborne BaP levels if samples from workers using respiratory protection or with significant dermal exposure were excluded. Urinary 1-OHP

  18. Witkacy’s Paradises

    Directory of Open Access Journals (Sweden)

    Giovanna Tomassucci

    2010-01-01

    Full Text Available The studies on Witkacy’s oeuvre Narcotics (Narkotyki, 1932 exist without any specific status, as if reduced to a research element ancillary to other “more serious” creative areas of its author. The above is especially astonishing since they belong to a specific literary genre which was started with De Quincy’s Confessions of an Opium Eater (1821 and became really successful in the 19th and 20th centuries, with Baudelaire, Cocteau, Artaud, Huxley and many others. Witkacy was the first Polishwriter who addressed the issue of drug addiction and wrote explicitly on the role of narcotics in artistic creation. He experimented with cocaine, mescaline, peyotl and discovered “the magic peyotl” in the same years as A. Artaud and W. Benjamin, and many years before Huxley. He was also one of the few writers who, after having experimented with drugs, began to deal with the theory of narcotics.The use of opium, cocaine, dawamesk also became a sort of caricatural form in many of his works from Cuttlefish (Mątwa up to the novel The Only Way Out (Jedyne wyjście. The aim of my work is to try to answer several questions: In what way does the author’s interest in the addiction of Unwashed Souls (Niemyte dusze fit into the 19th and 20th century debate between doctors, writers and European artists? Can Witkacy’s literary and dramatic work demonstrate that he was familiar with publications on pharmacology (published in Germany and France in the 20s and also with the authors who were writing about drugs in the 19th and 20th century? How does his prohibitionist point of view fit with his historiosophy? Can Narcotics be considered a literary work? I have also tried to determine the anonymous sources quoted by Witkacy and co-authors of Narcotics, B. Filipowski and S. Glass (pen name of Dezydery Prokopowicz.

  19. Nasal drug delivery: Design of a novel mucoadhesive and in situ gelling polymer.

    Science.gov (United States)

    Menzel, Claudia; Jelkmann, Max; Laffleur, Flavia; Bernkop-Schnürch, Andreas

    2017-01-30

    The aim of the present study was to establish a novel polymeric excipient for liquid nasal dosage forms exhibiting viscosity increasing properties, improved mucoadhesion and stability towards oxidation in solution. In order to achieve this goal, 2-mercaptonicotinic acid was first coupled to l-cysteine by disulfide exchange reaction and after purification directly attached to the polymeric backbone of xanthan gum by carbodiimide mediated amide bond formation. The resulting conjugate was characterized with respect to the amount of coupled ligand, the in situ gelling behavior, mucoadhesive properties and stability towards oxidation. Furthermore, the influence of preactivated polymers on ciliary beat frequency (CBF) of porcine nasal epithelial cells was investigated. Results showed, that 252.52±20.54μmol of the ligand was attached per gram polymer. No free thiol groups could be detected on the polymeric backbone indicating entire preactivation. Rheological investigations of polymer mucus mixtures revealed a 1.7-fold and 2.5-fold enhanced mucoadhesion of entirely preactivated xanthan (Xan-Cys-MNA) compared to thiolated xanthan (Xan-Cys) and unmodified xanthan (Xan). Tensile force evaluation reported a 2.87 and 5.11-fold higher total work of adhesion (TWA) as well as a 1.63 and 2.41-fold higher maximum detachement force of Xan-Cys-MNA compared to Xan-Cys and Xan. In the presence of H 2 O 2 as an oxidizing agent Xan-Cys-MNA showed unlike Xan-Cys no increase in viscosity, indicating high stability towards oxidation. Addition of CaCl 2 to Xan-Cys-MNA solutions caused a decrease in viscosity at nevertheless higher total viscosity. Results from CBF studies proved nasal safety for the novel conjugate. According to these results, entirely preactivated thiolated xanthan gum seems to be a promising excipient for nasal dosage forms in order to improve drug bioavailability. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Acute respiratory effects and biomarkers of inflammation due to welding-derived nanoparticle aggregates.

    Science.gov (United States)

    Dierschke, Katrin; Isaxon, Christina; Andersson, Ulla B K; Assarsson, Eva; Axmon, Anna; Stockfelt, Leo; Gudmundsson, Anders; Jönsson, Bo A G; Kåredal, Monica; Löndahl, Jakob; Pagels, Joakim; Wierzbicka, Aneta; Bohgard, Mats; Nielsen, Jörn

    2017-07-01

    Welders are exposed to airborne particles from the welding environment and often develop symptoms work-related from the airways. A large fraction of the particles from welding are in the nano-size range. In this study we investigate if the welders' airways are affected by exposure to particles derived from gas metal arc welding in mild steel in levels corresponding to a normal welding day. In an exposure chamber, 11 welders with and 10 welders without work-related symptoms from the lower airways and 11 non-welders without symptoms, were exposed to welding fumes (1 mg/m 3 ) and to filtered air, respectively, in a double-blind manner. Symptoms from eyes and upper and lower airways and lung function were registered. Blood and nasal lavage (NL) were sampled before, immediately after and the morning after exposure for analysis of markers of oxidative stress. Exhaled breath condensate (EBC) for analysis of leukotriene B4 (LT-B4) was sampled before, during and immediately after exposure. No adverse effects of welding exposure were found regarding symptoms and lung function. However, EBC LT-B4 decreased significantly in all participants after welding exposure compared to filtered air. NL IL-6 increased immediately after exposure in the two non-symptomatic groups and blood neutrophils tended to increase in the symptomatic welder group. The morning after, neutrophils and serum IL-8 had decreased in all three groups after welding exposure. Remarkably, the symptomatic welder group had a tenfold higher level of EBC LT-B4 compared to the two groups without symptoms. Despite no clinical adverse effects at welding, changes in inflammatory markers may indicate subclinical effects even at exposure below the present Swedish threshold limit (8 h TWA respirable dust).