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Attenuation Of Na/K-Atpase Mediated Oxidant Amplification With Pnaktide Ameliorates Experimental Uremic Cardiomyopathy, Jiang Liu, Jiang Tian, Muhammad Chaudhry, Kyle Maxwell, Yanling Yan, Xiaoliang Wang, Preeya T. Shah, Asad A. Khawaja, Rebecca Martin, Tylor J. Robinette, Adee El-Hamdani, Michael W. Dodrill, Komal Sodhi, Christopher A. Drummond, Steven T. Haller, David J. Keenedy, Nader G. Abraham, Zijian Xie, Joseph I. Shapiro Md

Nader G. Abraham

We have previously reported that the sodium potassium adenosine triphosphatase (Na/K-ATPase) can effect the amplification of reactive oxygen species. In this study, we examined whether attenuation of oxidant stress by antagonism of Na/K-ATPase oxidant amplification might ameliorate experimental uremic cardiomyopathy induced by partial nephrectomy (PNx). PNx induced the development of cardiac morphological and biochemical changes consistent with human uremic cardiomyopathy. Both inhibition of Na/K-ATPase oxidant amplification with pNaKtide and induction of heme oxygenase-1 (HO-1) with cobalt protoporphyrin (CoPP) markedly attenuated the development of phenotypical features of uremic cardiomyopathy. In a reversal study, administration of pNaKtide after the induction of uremic …

Attenuation Of Na/K-Atpase Mediated Oxidant Amplification With Pnaktide Ameliorates Experimental Uremic Cardiomyopathy, Jiang Liu, Jiang Tian, Muhammad Chaudhry, Kyle Maxwell, Yanling Yan, Xiaoliang Wang, Preeya T. Shah, Asad A. Khawaja, Rebecca Martin, Tylor J. Robinette, Adee El-Hamdani, Michael W. Dodrill, Komal Sodhi, Christopher A. Drummond, Steven T. Haller, David J. Keenedy, Nader G. Abraham, Zijian Xie, Joseph I. Shapiro Md

Komal Sodhi

We have previously reported that the sodium potassium adenosine triphosphatase (Na/K-ATPase) can effect the amplification of reactive oxygen species. In this study, we examined whether attenuation of oxidant stress by antagonism of Na/K-ATPase oxidant amplification might ameliorate experimental uremic cardiomyopathy induced by partial nephrectomy (PNx). PNx induced the development of cardiac morphological and biochemical changes consistent with human uremic cardiomyopathy. Both inhibition of Na/K-ATPase oxidant amplification with pNaKtide and induction of heme oxygenase-1 (HO-1) with cobalt protoporphyrin (CoPP) markedly attenuated the development of phenotypical features of uremic cardiomyopathy. In a reversal study, administration of pNaKtide after the induction of uremic …

Attenuation Of Na/K-Atpase Mediated Oxidant Amplification With Pnaktide Ameliorates Experimental Uremic Cardiomyopathy, Jiang Liu, Jiang Tian, Muhammad Chaudhry, Kyle Maxwell, Yanling Yan, Xiaoliang Wang, Preeya T. Shah, Asad A. Khawaja, Rebecca Martin, Tylor J. Robinette, Adee El-Hamdani, Michael W. Dodrill, Komal Sodhi, Christopher A. Drummond, Steven T. Haller, David J. Keenedy, Nader G. Abraham, Zijian Xie, Joseph I. Shapiro Md

Jiang Liu

We have previously reported that the sodium potassium adenosine triphosphatase (Na/K-ATPase) can effect the amplification of reactive oxygen species. In this study, we examined whether attenuation of oxidant stress by antagonism of Na/K-ATPase oxidant amplification might ameliorate experimental uremic cardiomyopathy induced by partial nephrectomy (PNx). PNx induced the development of cardiac morphological and biochemical changes consistent with human uremic cardiomyopathy. Both inhibition of Na/K-ATPase oxidant amplification with pNaKtide and induction of heme oxygenase-1 (HO-1) with cobalt protoporphyrin (CoPP) markedly attenuated the development of phenotypical features of uremic cardiomyopathy. In a reversal study, administration of pNaKtide after the induction of uremic …

Attenuation Of Na/K-Atpase Mediated Oxidant Amplification With Pnaktide Ameliorates Experimental Uremic Cardiomyopathy, Jiang Liu, Jiang Tian, Muhammad Chaudhry, Kyle Maxwell, Yanling Yan, Xiaoliang Wang, Preeya T. Shah, Asad A. Khawaja, Rebecca Martin, Tylor J. Robinette, Adee El-Hamdani, Michael W. Dodrill, Komal Sodhi, Christopher A. Drummond, Steven T. Haller, David J. Keenedy, Nader G. Abraham, Zijian Xie, Joseph I. Shapiro Md

Yanling Yan

We have previously reported that the sodium potassium adenosine triphosphatase (Na/K-ATPase) can effect the amplification of reactive oxygen species. In this study, we examined whether attenuation of oxidant stress by antagonism of Na/K-ATPase oxidant amplification might ameliorate experimental uremic cardiomyopathy induced by partial nephrectomy (PNx). PNx induced the development of cardiac morphological and biochemical changes consistent with human uremic cardiomyopathy. Both inhibition of Na/K-ATPase oxidant amplification with pNaKtide and induction of heme oxygenase-1 (HO-1) with cobalt protoporphyrin (CoPP) markedly attenuated the development of phenotypical features of uremic cardiomyopathy. In a reversal study, administration of pNaKtide after the induction of uremic …

Attenuation Of Na/K-Atpase Mediated Oxidant Amplification With Pnaktide Ameliorates Experimental Uremic Cardiomyopathy, Jiang Liu, Jiang Tian, Muhammad Chaudhry, Kyle Maxwell, Yanling Yan, Xiaoliang Wang, Preeya T. Shah, Asad A. Khawaja, Rebecca Martin, Tylor J. Robinette, Adee El-Hamdani, Michael W. Dodrill, Komal Sodhi, Christopher A. Drummond, Steven T. Haller, David J. Keenedy, Nader G. Abraham, Zijian Xie, Joseph I. Shapiro Md

Joseph I Shapiro MD

We have previously reported that the sodium potassium adenosine triphosphatase (Na/K-ATPase) can effect the amplification of reactive oxygen species. In this study, we examined whether attenuation of oxidant stress by antagonism of Na/K-ATPase oxidant amplification might ameliorate experimental uremic cardiomyopathy induced by partial nephrectomy (PNx). PNx induced the development of cardiac morphological and biochemical changes consistent with human uremic cardiomyopathy. Both inhibition of Na/K-ATPase oxidant amplification with pNaKtide and induction of heme oxygenase-1 (HO-1) with cobalt protoporphyrin (CoPP) markedly attenuated the development of phenotypical features of uremic cardiomyopathy. In a reversal study, administration of pNaKtide after the induction of uremic …

Multiple Scattering Theory For Polycrystalline Materials With Strong Grain Anisotropy: Theoretical Fundamentals And Applications, Huijing He

Huijing He

Hybrid Millimeter-Wave Systems: A Novel Paradigm For Hetnets, Hani Mehrpouyan, Michail Matthaiou, Rui Wang, George K. Karagiannidis, Yingbo Hua

Hani Mehrpouyan

Heterogeneous Networks (HetNets) are known to enhance the bandwidth efficiency and throughput of wireless networks by more effectively utilizing the network resources. However, the higher density of users and access points in HetNets introduces significant inter-user interference that needs to be mitigated through complex and sophisticated interference cancellation schemes. Moreover, due to significant channel attenuation and presence of hardware impairments, e.g., phase noise and amplifier nonlinearities, the vast bandwidth in the millimeter-wave band has not been fully utilized to date. In order to enable the development of multi-Gigabit per second wireless networks, we introduce a novel millimeter-wave HetNet paradigm, termed …

A Weakened Mechanism Is Still A Mechanism: On The Causal Role Of Absences In Mechanistic Explanation, Alexander Mebius

Alexander Mebius

Much contemporary debate on the nature of mechanisms centers on the issue of modulating negative causes. One type of negative causability, which I refer to as ‘‘causation by absence,’’ appears difficult to incorporate into modern accounts of mechanistic explanation. This paper argues that a recent attempt to resolve this problem, proposed by Benjamin Barros, requires improvement as it overlooks the fact that not all absences qualify as sources of mechanism failure. I suggest that there are a number of additional types of effects caused by absences that need to be incorporated to account for the diversity of causal connections in …

Improving Bandwidth Efficiency In E-Band Communication Systems, Hani Mehrpouyan, M. Reza Khanzadi, Michail Matthaiou, Akbar M. Sayeed, Robert Schober, Yingbo Hua

Hani Mehrpouyan

The allocation of a large amount of bandwidth by regulating bodies in the 70/80 GHz band, that is, the E-band, has opened up new potentials and challenges for providing affordable and reliable gigabit-per-second wireless point-to-point links. This article first reviews the available bandwidth and licensing regulations in the E-band. Subsequently, different propagation models (e.g., the ITU-R and Cane models) are compared against measurement results, and it is concluded that to meet specific availability requirements, E-band wireless systems may need to be designed with larger fade margins compared to microwave systems. A similar comparison is carried out between measurements …

Impact Of Mains Connected Three-Phase Induction Motor Loading Levels On Network Voltage Unbalance Attenuation, Upuli Jayatunga, Sarath Perera, Philip Ciufo

Dr Philip Ciufo

Voltage unbalance (VU) in power systems should be managed in a systematic manner in order to minimise its adverse effects on both customer equipment and supply utilities. It is a well known fact that three-phase induction motor performance can be significantly affected in the presence of supply voltage unbalance. It is also known that three-phase induction motors can help to reduce pre-existing network voltage unbalance levels. Recently undertaken research aligned with IEC/TR 61000-3-13:2008 Technical Report on voltage unbalance management (emission allocation and emission assessment) have quantified the contribution made by induction motors to the net voltage unbalance at a point …

Impact Of Local Attenuation Approximations When Estimating Correlation Length From Backscattered Ultrasound Echoes, Timothy A. Bigelow, William D. O'Brien

Timothy A. Bigelow

Estimating the characteristic correlation length of tissue microstructure from the backscattered power spectrum could improve the diagnostic capability of medical ultrasound. Previously, size estimates were obtained after compensating for source focusing, the frequency-dependent attenuation along the propagation path (total attenuation), and the frequency-dependent attenuation in the scattering region (local attenuation). In this study, the impact of approximations of the local attenuation on the scatterer size estimate was determined using computer simulations and theoretical analysis. The simulations used Gaussian impedance distributions with an effective radius of 25 μm randomly positioned in a homogeneous half-space sonified by a spherically focused source (f/1 …

Signal Processing Strategies That Improve Performance And Understanding Of The Quantitative Ultrasound Spectral Fit Algorithm, Timothy A. Bigelow, William D. O'Brien

Timothy A. Bigelow

Quantifying the size of the tissue microstructure using the backscattered power spectrum has had limited success due to frequency-dependent attenuation along the propagation path, thus masking the frequency dependence of the scatterer size. Previously, the SPECTRAL FIT algorithm was developed to solve for total attenuation and scatterer size simultaneously [Bigelow et al., J. Acoust. Soc. Am. 117, 1431-1439 (2005)]. Herein, the outcomes from signal processing strategies on the SPECTRAL FIT algorithm are investigated. The signal processing methods can be grouped into two categories, viz., methods that improve the performance of the algorithm and methods that provide insight. The methods that …

A Model For Estimating Ultrasound Attenuation Along The Propagation Path To The Fetus From Backscattered Waveforms, Timothy A. Bigelow, William D. O'Brien

Timothy A. Bigelow

Accurate estimates of the ultrasound pressure and/or intensity incident on the developing fetus on a patient-specific basis could improve the diagnostic potential of medical ultrasound by allowing the clinician to increase the transmit power while still avoiding the potential for harmful bioeffects. Neglecting nonlinear effects, the pressure/intensity can be estimated if an accurate estimate of the attenuation along the propagation path (i.e., total attenuation) can be obtained. Herein, a method for determining the total attenuation from the backscattered power spectrum from the developing fetus is proposed. The boundaries between amnion and either the fetus' skull or soft tissue are each …

Estimation Of Total Attenuation And Scatterer Size From Backscattered Ultrasound Waveforms, Timothy A. Bigelow, Michael L. Oelze, William D. O'Brien

Timothy A. Bigelow

Quantitative ultrasound techniques using backscattered echoes have had limited success in vivo due to the frequency-dependent attenuation along the entire propagation path masking the frequency dependence of the backscatter. Herein, total attenuation and scatterer size are estimated simultaneously by an analysis of the in vivo backscattered power spectrum using two approaches. The simulations used to evaluate the two approaches used frequencies between 4 and 11 MHz with an effective scatterer radius of 25 μm. The first approach was based on approximations of the in vivo backscattered power spectrum (i.e., assumed Gaussian function), wherein attenuation and size were estimated by assuming …

Scatterer Size Estimation In Pulse-Echo Ultrasound Using Focused Sources: Calibration Measurements And Phantom Experiments, Timothy A. Bigelow, William D. O'Brien

Timothy A. Bigelow

In a companion paper [T. A. Bigelow and W. D. O'Brien Jr., J. Acoust. Soc. Am. 116, 578 (2004)], theory, supported by simulations, showed that accurate scatterer size estimates could be obtained using highly focused sources provided that the derived generalized attenuation-compensation function was used and the velocity potential field near the focus could be approximated as a three-dimensional Gaussian. Herein, the theory is further evaluated via experimental studies. A calibration technique is developed to find the necessary equivalent Gaussian dimensions for a focused source using reflections obtained from a rigid plane scanned through the focus. Then, the theoretical analysis …

Scatterer Size Estimation In Pulse-Echo Ultrasound Using Focused Sources: Theoretical Approximations And Simulation Analysis, Timothy A. Bigelow, William D. O'Brien

Timothy A. Bigelow

The speckle in ultrasound images has long been thought to contain information related to the tissue microstructure. Many different investigators have analyzed the frequency characteristics of the backscattered signals to estimate the scatterer acoustic concentration and size. Previous work has been mostly restricted to unfocused or weakly focused ultrasound sources, thus limiting its implementation with diagnostically relevant fields. Herein, we derive equations capable of estimating the size of a-scatterer for any reasonably focused source provided that the velocity potential field in the focal region can be approximated as a three-dimensional Gaussian beam, scatterers are a sufficient distance from the source, …

Simple Scheme For Variable High Power Laser Beam Attenuation, Stephen E. Bialkowski

Stephen E. Bialkowski

A venetian style infrared attenuator placed prior to a pinhole spatial filter results in variable high‐power laser attenuation. This attenuation scheme has a wide dynamic range, results in high‐quality Gaussian beams, does not introduce beam walk‐off error, and is independent of polarization.