Quantification of Maceration Changes using Post Mortem MRI in Fetuses

BACKGROUND: Post mortem imaging is playing an increasingly important role in perinatal autopsy, and correct interpretation of imaging changes is paramount. This is particularly important following intra-uterine fetal death, where there may be fetal maceration. The aim of this study was to investigate whether any changes seen on a whole body fetal post mortem magnetic resonance imaging (PMMR) correspond to maceration at conventional autopsy. METHODS: We performed pre-autopsy PMMR in 75 fetuses using a 1.5 Tesla Siemens Avanto MR scanner (Erlangen, Germany). PMMR images were reported blinded to the clinical history and autopsy data using a numerical severity scale (0 = no maceration changes to 2 = severe maceration changes) for 6 different visceral organs (total 12). The degree of maceration at autopsy was categorized according to severity on a numerical scale (1 = no maceration to 4 = severe maceration). We also generated quantitative maps to measure the liver and lung T2. RESULTS: The mean PMMR maceration score correlated well with the autopsy maceration score (R(2) = 0.93). A PMMR score of ≥4.5 had a sensitivity of 91%, specificity of 64%, for detecting moderate or severe maceration at autopsy. Liver and lung T2 were increased in fetuses with maceration scores of 3-4 in comparison to those with 1-2 (liver p = 0.03, lung p = 0.02). CONCLUSIONS: There was a good correlation between PMMR maceration score and the extent of maceration seen at conventional autopsy. This score may be useful in interpretation of fetal PMMR

Driven From Home

https://digitalcommons.library.umaine.edu/mmb-ps/1981/thumbnail.jp

The Band Excitation Method in Scanning Probe Microscopy for Rapid Mapping of Energy Dissipation on the Nanoscale

Mapping energy transformation pathways and dissipation on the nanoscale and understanding the role of local structure on dissipative behavior is a challenge for imaging in areas ranging from electronics and information technologies to efficient energy production. Here we develop a novel Scanning Probe Microscopy (SPM) technique in which the cantilever is excited and the response is recorded over a band of frequencies simultaneously rather than at a single frequency as in conventional SPMs. This band excitation (BE) SPM allows very rapid acquisition of the full frequency response at each point (i.e. transfer function) in an image and in particular enables the direct measurement of energy dissipation through the determination of the Q-factor of the cantilever-sample system. The BE method is demonstrated for force-distance and voltage spectroscopies and for magnetic dissipation imaging with sensitivity close to the thermomechanical limit. The applicability of BE for various SPMs is analyzed, and the method is expected to be universally applicable to all ambient and liquid SPMs.Comment: 32 pages, 9 figures, accepted for publication in Nanotechnolog

Aid to conflict-affected countries : lessons for donors

The first section looks at the implications of conflict for aid effectiveness and selectivity. We argue that, while aid is generally effective in promoting growth and by implication reducing poverty, it is more effective in promoting growth in post-conflict countries. We then consider the implications of these findings for donor selectivity models and for assessment of donor performance in allocating development aid among recipient countries. We argue that, while further research on aid effectiveness in post-conflict scenarios is needed, existing selectivity models should be augmented with, inter alia, post-conflict variables, and donors should be evaluated on the basis, inter alia, of the share of their aid budgets allocated to countries experiencing post-conflict episodes. We also argue for aid delivered in the form of projects to countries with weak institutions in early post-conflict years. The second section focuses on policies for donors operating in conflict-affected countries. We set out five of the most important principles: (1) focus on broad-based recovery from war; (2) to achieve a broad-based recovery, get involved before the conflict ends; (3) focus on poverty, but avoid &lsquo;wish lists&rsquo;; (4) help to reduce insecurity so aid can contribute more effectively to growth and poverty reduction; and (5) in economic reform, focus on improving public expenditure management and revenue mobilisation. The third section concludes by emphasising the fact that there is no hard or fast dividing line between &lsquo;war&rsquo; and &lsquo;peace&rsquo; and that it may take many years for a society to become truly &lsquo;post&rsquo;-conflict&rsquo;. Donors, therefore, need to prepare for the long haul.<br /

Microstructure identification via detrended fluctuation analysis of ultrasound signals

We describe an algorithm for simulating ultrasound propagation in random one-dimensional media, mimicking different microstructures by choosing physical properties such as domain sizes and mass densities from probability distributions. By combining a detrended fluctuation analysis (DFA) of the simulated ultrasound signals with tools from the pattern-recognition literature, we build a Gaussian classifier which is able to associate each ultrasound signal with its corresponding microstructure with a very high success rate. Furthermore, we also show that DFA data can be used to train a multilayer perceptron which estimates numerical values of physical properties associated with distinct microstructures.Comment: Submitted to Phys. Rev.

Wage effects of works councils and opening clauses: the German case

"German employment relations are characterized by a distinct dual system. First, working conditions and wages are determined by industry-level collective bargaining agreements. Second, on the establishment-level, the works council is responsible for employer - employee negotiations. However, since the mid-1980s, an increasing number of areas of regulation have been transferred from the industry- to the establishment-level using so-called opening clauses. The analysis in this article relies on rich German establishment data and reveals new insights into the institutional machinery of wage bargaining. While the existence of such clauses is related to higher wages, their application results in wage cuts of roughly the same size. The results also suggest that works councils, on average, are able to prevent the negative wage effects of opening clauses." (Author's abstract, IAB-Doku) ((en)

The stationary wavelet transform as an efficient reductor of powerline interference for atrial bipolar electrograms in cardiac electrophysiology

[EN] Objective :The most relevant source of signal contamination in the cardiac electrophysiology (EP) laboratory is the ubiquitous powerline interference (PLI). To reduce this perturbation, algorithms including common fixed-bandwidth and adaptive-notch filters have been proposed. Although such methods have proven to add artificial fractionation to intra-atrial electrograms (EGMs), they are still frequently used. However, such morphological alteration can conceal the accurate interpretation of EGMs, specially to evaluate the mechanisms supporting atrial fibrillation (AF), which is the most common cardiac arrhythmia. Given the clinical relevance of AF, a novel algorithm aimed at reducing PLI on highly contaminated bipolar EGMs and, simultaneously, preserving their morphology is proposed. Approach: The method is based on the wavelet shrinkage and has been validated through customized indices on a set of synthesized EGMs to accurately quantify the achieved level of PLI reduction and signal morphology alteration. Visual validation of the algorithm¿s performance has also been included for some real EGM excerpts. Main results: The method has outperformed common filtering-based and wavelet-based strategies in the analyzed scenario. Moreover, it possesses advantages such as insensitivity to amplitude and frequency variations in the PLI, and the capability of joint removal of several interferences. Significance: The use of this algorithm in routine cardiac EP studies may enable improved and truthful evaluation of AF mechanisms.Research supported by grants DPI2017-83952-C3 MINECO/AEI/FEDER, UE and SBPLY/17/180501/000411 from Junta de Comunidades de Castilla-La Mancha.Martinez-Iniesta, M.; Ródenas, J.; Rieta, JJ.; Alcaraz, R. (2019). The stationary wavelet transform as an efficient reductor of powerline interference for atrial bipolar electrograms in cardiac electrophysiology. Physiological Measurement. 40(7):1-17. https://doi.org/10.1088/1361-6579/ab2cb8S117407Addison, P. S. (2017). The Illustrated Wavelet Transform Handbook. doi:10.1201/9781315372556Allen, D. P. (2009). A frequency domain Hampel filter for blind rejection of sinusoidal interference from electromyograms. Journal of Neuroscience Methods, 177(2), 303-310. doi:10.1016/j.jneumeth.2008.10.019Atienza, F., Almendral, J., Jalife, J., Zlochiver, S., Ploutz-Snyder, R., Torrecilla, E. G., … Berenfeld, O. (2009). Real-time dominant frequency mapping and ablation of dominant frequency sites in atrial fibrillation with left-to-right frequency gradients predicts long-term maintenance of sinus rhythm. Heart Rhythm, 6(1), 33-40. doi:10.1016/j.hrthm.2008.10.024Atienza, F., Almendral, J., Moreno, J., Vaidyanathan, R., Talkachou, A., Kalifa, J., … Berenfeld, O. (2006). Activation of Inward Rectifier Potassium Channels Accelerates Atrial Fibrillation in Humans. Circulation, 114(23), 2434-2442. doi:10.1161/circulationaha.106.633735Bahoura, M., & Ezzaidi, H. (2011). FPGA-Implementation of Discrete Wavelet Transform with Application to Signal Denoising. Circuits, Systems, and Signal Processing, 31(3), 987-1015. doi:10.1007/s00034-011-9355-0Baumert, M., Sanders, P., & Ganesan, A. (2016). Quantitative-Electrogram-Based Methods for Guiding Catheter Ablation in Atrial Fibrillation. Proceedings of the IEEE, 104(2), 416-431. doi:10.1109/jproc.2015.2505318Castillo, E., Morales, D. P., García, A., Martínez-Martí, F., Parrilla, L., & Palma, A. J. (2013). Noise Suppression in ECG Signals through Efficient One-Step Wavelet Processing Techniques. Journal of Applied Mathematics, 2013, 1-13. doi:10.1155/2013/763903Chen, S.-W., & Chen, Y.-H. (2015). Hardware Design and Implementation of a Wavelet De-Noising Procedure for Medical Signal Preprocessing. Sensors, 15(10), 26396-26414. doi:10.3390/s151026396El B’charri, O., Latif, R., Elmansouri, K., Abenaou, A., & Jenkal, W. (2017). ECG signal performance de-noising assessment based on threshold tuning of dual-tree wavelet transform. BioMedical Engineering OnLine, 16(1). doi:10.1186/s12938-017-0315-1Everett, T. H., Lai-Chow Kok, Vaughn, R. H., Moorman, R., & Haines, D. E. (2001). Frequency domain algorithm for quantifying atrial fibrillation organization to increase defibrillation efficacy. IEEE Transactions on Biomedical Engineering, 48(9), 969-978. doi:10.1109/10.942586Ganesan, A. N., Kuklik, P., Lau, D. H., Brooks, A. G., Baumert, M., Lim, W. W., … Sanders, P. (2013). Bipolar Electrogram Shannon Entropy at Sites of Rotational Activation. Circulation: Arrhythmia and Electrophysiology, 6(1), 48-57. doi:10.1161/circep.112.976654Goldberger, A. L., Amaral, L. A. N., Glass, L., Hausdorff, J. M., Ivanov, P. C., Mark, R. G., … Stanley, H. E. (2000). PhysioBank, PhysioToolkit, and PhysioNet. Circulation, 101(23). doi:10.1161/01.cir.101.23.e215GOLDBERGER, J. J. (2017). Substrate Ablation for Treatment of Atrial Fibrillation: Back to Basics. Journal of Cardiovascular Electrophysiology, 28(2), 156-158. doi:10.1111/jce.13149Gutiérrez-Gnecchi, J. A., Morfin-Magaña, R., Lorias-Espinoza, D., Tellez-Anguiano, A. del C., Reyes-Archundia, E., Méndez-Patiño, A., & Castañeda-Miranda, R. (2017). DSP-based arrhythmia classification using wavelet transform and probabilistic neural network. Biomedical Signal Processing and Control, 32, 44-56. doi:10.1016/j.bspc.2016.10.005Hamilton, P. S. (1996). A comparison of adaptive and nonadaptive filters for reduction of power line interference in the ECG. IEEE Transactions on Biomedical Engineering, 43(1), 105-109. doi:10.1109/10.477707Heijman, J., Algalarrondo, V., Voigt, N., Melka, J., Wehrens, X. H. T., Dobrev, D., & Nattel, S. (2015). The value of basic research insights into atrial fibrillation mechanisms as a guide to therapeutic innovation: a critical analysis. Cardiovascular Research, 109(4), 467-479. doi:10.1093/cvr/cvv275Honarbakhsh, S., Schilling, R. J., Orini, M., Providencia, R., Keating, E., Finlay, M., … Hunter, R. J. (2019). Structural remodeling and conduction velocity dynamics in the human left atrium: Relationship with reentrant mechanisms sustaining atrial fibrillation. Heart Rhythm, 16(1), 18-25. doi:10.1016/j.hrthm.2018.07.019Jadidi, A. S., Lehrmann, H., Weber, R., Park, C.-I., & Arentz, T. (2013). Optimizing Signal Acquisition and Recording in an Electrophysiology Laboratory. Cardiac Electrophysiology Clinics, 5(2), 137-142. doi:10.1016/j.ccep.2013.01.005JARMAN, J. W. E., WONG, T., KOJODJOJO, P., SPOHR, H., DAVIES, J. E. R., ROUGHTON, M., … PETERS, N. S. (2014). Organizational Index Mapping to Identify Focal Sources During Persistent Atrial Fibrillation. Journal of Cardiovascular Electrophysiology, 25(4), 355-363. doi:10.1111/jce.12352KOTTKAMP, H., BERG, J., BENDER, R., RIEGER, A., & SCHREIBER, D. (2015). Box Isolation of Fibrotic Areas (BIFA): A Patient-Tailored Substrate Modification Approach for Ablation of Atrial Fibrillation. Journal of Cardiovascular Electrophysiology, 27(1), 22-30. doi:10.1111/jce.12870Krijthe, B. P., Kunst, A., Benjamin, E. J., Lip, G. Y. H., Franco, O. H., Hofman, A., … Heeringa, J. (2013). Projections on the number of individuals with atrial fibrillation in the European Union, from 2000 to 2060. European Heart Journal, 34(35), 2746-2751. doi:10.1093/eurheartj/eht280Lau, D. H., Schotten, U., Mahajan, R., Antic, N. A., Hatem, S. N., Pathak, R. K., … Sanders, P. (2015). Novel mechanisms in the pathogenesis of atrial fibrillation: practical applications. European Heart Journal, 37(20), 1573-1581. doi:10.1093/eurheartj/ehv375Lenis, G., Pilia, N., Loewe, A., Schulze, W. H. W., & Dössel, O. (2017). Comparison of Baseline Wander Removal Techniques considering the Preservation of ST Changes in the Ischemic ECG: A Simulation Study. Computational and Mathematical Methods in Medicine, 2017, 1-13. doi:10.1155/2017/9295029Levkov, C., Mihov, G., Ivanov, R., Daskalov, I., Christov, I., & Dotsinsky, I. (2005). Removal of power-line interference from the ECG: a review of the subtraction procedure. BioMedical Engineering OnLine, 4(1). doi:10.1186/1475-925x-4-50Lian, J., Garner, G., Muessig, D., & Lang, V. (2010). A simple method to quantify the morphological similarity between signals. Signal Processing, 90(2), 684-688. doi:10.1016/j.sigpro.2009.07.010Liu, H., Li, Y., Zhou, Y., Jing, X., & Truong, T.-K. (2018). Joint power line interference suppression and ECG signal recovery in transform domains. Biomedical Signal Processing and Control, 44, 58-66. doi:10.1016/j.bspc.2018.04.001Mamun, M., Al-Kadi, M., & Marufuzzaman, M. (2013). Effectiveness of Wavelet Denoising on Electroencephalogram Signals. Journal of Applied Research and Technology, 11(1), 156-160. doi:10.1016/s1665-6423(13)71524-4Martens, S. M. M., Mischi, M., Oei, S. G., & Bergmans, J. W. M. (2006). An Improved Adaptive Power Line Interference Canceller for Electrocardiography. IEEE Transactions on Biomedical Engineering, 53(11), 2220-2231. doi:10.1109/tbme.2006.883631Mart�nez, M., R�denas, J., Alcaraz, R., & Rieta, J. J. (2017). Application of the Stationary Wavelet Transform to Reduce Power-line Interference in Atrial Electrograms. 2017 Computing in Cardiology Conference (CinC). doi:10.22489/cinc.2017.112-049Martínez-Iniesta, M., Ródenas, J., Alcaraz, R., & Rieta, J. J. (2017). Waveform Integrity in Atrial Fibrillation: The Forgotten Issue of Cardiac Electrophysiology. Annals of Biomedical Engineering, 45(8), 1890-1907. doi:10.1007/s10439-017-1832-6Metting van Rijn, A. C., Peper, A., & Grimbergen, C. A. (1990). High-quality recording of bioelectric events. Medical & Biological Engineering & Computing, 28(5), 389-397. doi:10.1007/bf02441961Nademanee, K., McKenzie, J., Kosar, E., Schwab, M., Sunsaneewitayakul, B., Vasavakul, T., … Ngarmukos, T. (2004). A new approach for catheter ablation of atrial fibrillation: mapping of the electrophysiologic substrate. Journal of the American College of Cardiology, 43(11), 2044-2053. doi:10.1016/j.jacc.2003.12.054Naseri, H., & Homaeinezhad, M. R. (2012). Computerized quality assessment of phonocardiogram signal measurement-acquisition parameters. Journal of Medical Engineering & Technology, 36(6), 308-318. doi:10.3109/03091902.2012.684832NG, J., BORODYANSKIY, A. I., CHANG, E. T., VILLUENDAS, R., DIBS, S., KADISH, A. H., & GOLDBERGER, J. J. (2010). Measuring the Complexity of Atrial Fibrillation Electrograms. Journal of Cardiovascular Electrophysiology, 21(6), 649-655. doi:10.1111/j.1540-8167.2009.01695.xNg, J., Sehgal, V., Ng, J. K., Gordon, D., & Goldberger, J. J. (2014). Iterative Method to Detect Atrial Activations and Measure Cycle Length From Electrograms During Atrial Fibrillation. IEEE Transactions on Biomedical Engineering, 61(2), 273-278. doi:10.1109/tbme.2013.2290003Oesterlein, T. G., Lenis, G., Rudolph, D.-T., Luik, A., Verma, B., Schmitt, C., & Dössel, O. (2015). Removing ventricular far-field signals in intracardiac electrograms during stable atrial tachycardia using the periodic component analysis. Journal of Electrocardiology, 48(2), 171-180. doi:10.1016/j.jelectrocard.2014.12.004Platonov, P. G., Corino, V. D. A., Seifert, M., Holmqvist, F., & Sornmo, L. (2014). Atrial fibrillatory rate in the clinical context: natural course and prediction of intervention outcome. Europace, 16(suppl 4), iv110-iv119. doi:10.1093/europace/euu249Poornachandra, S., & Kumaravel, N. (2008). A novel method for the elimination of power line frequency in ECG signal using hyper shrinkage function. Digital Signal Processing, 18(2), 116-126. doi:10.1016/j.dsp.2007.03.011Quintanilla, J. G., Pérez-Villacastín, J., Pérez-Castellano, N., Pandit, S. V., Berenfeld, O., Jalife, J., & Filgueiras-Rama, D. (2016). Mechanistic Approaches to Detect, Target, and Ablate the Drivers of Atrial Fibrillation. Circulation: Arrhythmia and Electrophysiology, 9(1). doi:10.1161/circep.115.002481Ravelli, F., Masè, M., Cristoforetti, A., Marini, M., & Disertori, M. (2014). The logical operator map identifies novel candidate markers for critical sites in patients with atrial fibrillation. Progress in Biophysics and Molecular Biology, 115(2-3), 186-197. doi:10.1016/j.pbiomolbio.2014.07.006Schanze, T. (2017). Removing noise in biomedical signal recordings by singular value decomposition. Current Directions in Biomedical Engineering, 3(2), 253-256. doi:10.1515/cdbme-2017-0052Schotten, U., Dobrev, D., Platonov, P. G., Kottkamp, H., & Hindricks, G. (2016). Current controversies in determining the main mechanisms of atrial fibrillation. Journal of Internal Medicine, 279(5), 428-438. doi:10.1111/joim.12492Singh, B. N., & Tiwari, A. K. (2006). Optimal selection of wavelet basis function applied to ECG signal denoising. Digital Signal Processing, 16(3), 275-287. doi:10.1016/j.dsp.2005.12.003Van Wagoner, D. R., Piccini, J. P., Albert, C. M., Anderson, M. E., Benjamin, E. J., Brundel, B., … Wehrens, X. H. T. (2015). Progress toward the prevention and treatment of atrial fibrillation: A summary of the Heart Rhythm Society Research Forum on the Treatment and Prevention of Atrial Fibrillation, Washington, DC, December 9–10, 2013. Heart Rhythm, 12(1), e5-e29. doi:10.1016/j.hrthm.2014.11.011Venkatachalam, K. L., Herbrandson, J. E., & Asirvatham, S. J. (2011). Signals and Signal Processing for the Electrophysiologist. Circulation: Arrhythmia and Electrophysiology, 4(6), 965-973. doi:10.1161/circep.111.96430

Observation of Spin Wave Soliton Fractals in Magnetic Film Active Feedback Rings

The manifestation of fractals in soliton dynamics has been observed for the first time. The experiment utilized self-generated spin wave envelope solitons in a magnetic film based active feedback ring. At high ring gain, the soliton that circulates in the ring breathes in a fractal pattern. The corresponding power frequency spectrum shows a comb structure, with each peak in the comb having its own comb, and so on, to finer and finer scales.Comment: 4 pages, 4 figure

Association between Physical Activity and Mortality in Patients with Claudication

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