New Frank-Starling based contractility and ventricular stiffness indices: clinically applicable alternative to Emax

2013 Summer.Includes bibliographical references.Heart disease is the #1 cause of death in the United States with congestive heart failure (CHF) being a leading component. Load induced CHF, i.e. CHF in response to chronic pressure or volume overload, may be classified either as systolic failure or diastolic failure, depending on the failure mode of the pumping chamber. To assess the severity of systolic failure, there exist clinical indices that quantify chamber contractility, namely: ejection fraction, (dP/dt), Emax (related to the rate of pressure rise in the pumping chamber), and Emax (related to the time-dependent elastance property of the ventricle). Unfortunately, these indices are plagued with limitations due to inherent load dependence or difficulty in clinical implementation. Indices to assess severity of diastolic failure are also limited due to load dependence. The goal of this research is to present (1) a new framework that defines a new contractility index, Tmax, and ventricular compliance 'a', based on Frank-Starling concepts that can be easily applied to human catheterization data, and (2) discusses preliminary findings in patients at various stages of valve disease. A lumped parameter model of the pumping ventricle was constructed utilizing the basic principles of the Frank-Startling law. The systemic circulation was modeled as a three element windkessel block for the arterial and venous elements. Based on the Frank-Starling curve, the new contractility index, Tmax and ventricular compliance 'a' were defined. Simulations were conducted to validate the load independence of Tmax and a computed from a novel technique based on measurements corresponding to the iso-volumetric contraction phase. Recovered Tmax and 'a' depicted load independence and deviated only a few % points from their true values. The new technique was implemented to establish the baseline Tmax and 'a' in normal human subjects from a retrospective meta-data analysis of published cardiac catheterization data. In addition, Tmax and 'a' was quantified in 12 patients with a prognosis of a mix of systolic and diastolic ventricular failure. Statistical analysis showed that Tmax was significantly different between the normal subjects group and systolic failure group (p<0.019) which implies that a decrease in Tmax indeed predicts impending systolic dysfunction. Analysis of human data also shows that the ventricular compliance index 'a' is significantly different between the normal subjects and concentric hypertrophy (p < 0.001). This research has presented a novel technique to recover load independent measures of contractility and ventricular compliance from standard cardiac catheterization data

Machine learning-based fusion studies of rainfall estimation from spaceborne and ground-based radars

2019 Spring.Includes bibliographical references.Precipitation measurement by satellite radar plays a significant role in researching the water circle and forecasting extreme weather event. Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) has capability of providing a high-resolution vertical profile of precipitation over the tropics regions. Its successor, Global Precipitation Measurement (GPM) Dual-frequency Precipitation Radar (DPR), can provide detailed information on the microphysical properties of precipitation particles, quantify particle size distribution and quantitatively measure light rain and falling snow. This thesis presents a novel Machine Learning system for ground-based and space borne radar rainfall estimation. The system first trains ground radar data for rainfall estimation using rainfall measurements from gauges and subsequently uses the ground radar based rainfall estimates to train spaceborne radar data in order to get space based rainfall product. Therein, data alignment between spaceborne and ground radar is conducted using the methodology proposed by Bolen and Chandrasekar (2013), which can minimize the effects of potential geometric distortion of spaceborne radar observations. For demonstration purposes, rainfall measurements from three rain gauge networks near Melbourne, Florida, are used for training and validation purposes. These three gauge networks, which are located in Kennedy Space Center (KSC), South Florida Water Management District (SFL), and St. Johns Water Management District (STJ), include 33, 46, and 99 rain gauge stations, respectively. Collocated ground radar observations from the National Weather Service (NWS) Weather Surveillance Radar – 1988 Doppler (WSR-88D) in Melbourne (i.e., KMLB radar) are trained with the gauge measurements. The trained model is then used to derive KMLB radar based rainfall product, which is used to train both TRMM PR and GPM DPR data collected from coincident overpasses events. The machine learning based rainfall product is compared against the standard satellite products, which shows great potential of the machine learning concept in satellite radar rainfall estimation. Also, the local rain maps generated by machine learning system at KMLB area are demonstrate the application potential

Enhanced photocatalytic oxidation of SO2 on TiO2 surface by Na2CO3 modification

The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.cej.2018.05.128 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/The effects of Na2CO3 on the photocatalytic oxidation (PCO) of SO2 with UV irradiated TiO2 (P25) were studied using a fixed bed reactor. Na2CO3 was loaded onto P25 using a wet coating method. The PCO efficiency for SO2 with P25 was enhanced by 1.6 and 10.6 times using 0.05 M and 0.2 M Na2CO3 modified P25, respectively. The enhancement of the photocatalytic activity of P25 by Na2CO3 was observed only with the presence of water vapor. Low temperature (113 K) electron spinning resonance (ESR) analysis showed that Na2CO3 promoted the photoinduced electron-hole separation by trapping valance band holes and forming carbonate radicals (CO3−). The ESR spin trapping analyses showed a remarkable increase in the intensity of [DMPO-OH] adducts with the addition of Na2CO3. This increase phenomena indicates that more reactive species were formed on the P25 surface. The deposited Na2CO3 inhibited the recombination of electron-hole pairs and promoted the generation of hydroxyl radicals (OH), most likely through the photo-reduction of O2 adsorbed by the conduction band electrons. The generated •OH radicals reacted with SO2 rapidly and improved the PCO effectiveness of P25.National Key Research and Development Program of China ["2017YFB0603903"

Pairing Superfluid–Insulator Transition Induced by Atom–Molecule Conversion in Bosonic Mixtures in Optical Lattice

Motivated by the recent experiment on bosonic mixtures of atoms and molecules, we investigate pairing superfluid–insulator (SI) transition for bosonic mixtures of atoms and molecules in a one-dimensional optical lattice, which is described by an extended Bose–Hubbard model with atom–molecule conservation (AMC). It is found that AMC can induce an extra pair–superfluid phase though the system does not demonstrate pair-hopping. In particular, the system may undergo several pairing SI or insulator–superfluid transitions as the detuning from the Feshbach resonance is varied from negative to positive, and the larger positive detuning can bifurcate the pair–superfluid phases into mixed superfluid phases consisting of single-atomic and pair-atomic superfluid. The calculation of the second-order Rényi entropy reveals that the discontinuity in its first-order derivative corresponds to the phase boundary of the pairing SI transition. This means that the residual entanglement in our mean-field treatment can be used to efficiently capture the signature of the pairing SI transition induced by AMC

Application of urea precipitation method in preparation of advanced ceramic powders

Urea precipitation method has been developed as an important approach for the preparation of inorganic particles with defined morphology and composition. In present work, we provide survey of the technological developments and achievements mainly on the application of the urea precipitation method in preparation of advanced ceramics powders. Stable pH obtained during the thermal decomposition of urea in aqueous solution make it quite promising for the precise composition control of ultrafine powders. The decomposition mechanism of urea in aqueous solution is discussed before a systematic description of its application in the preparation of monodispersed particles with unary/binary composition. Clear decomposition mechanism of urea provides researchers a possibility to analyze the evolution process of ultrafine particles from its initial forming period. Finally, the application potential and future prospects of this method, such as preparation of core shell particle with designed composition and precipitation kinetics study, are outlined. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Accelerated recrystallization and improved goss texture of Fe–3Si silicon steel strip via electropulsing treatment

Recrystallization behaviour and texture evolution of Fe–3Si alloy strip by electropulsing treatment (EPT) were investigated through EBSD and X-ray diffraction techniques. It was found that EPT remarkably reduced recrystallization temperature of Fe–3Si alloy, induced full recrystallization at 550 °C in a short time (10 s), fine and uniform recrystallization grains accompanied with a small amount of Goss orientated grains were obtained. Compared with the conventional isothermal annealing, EPT effectively promoted the nucleation of Goss orientated recrystallization grains and suppressed swallowing of Goss orientated grains by other oriented grains due to both short treatment time and fast cooling rate of EPT, which was the main reason for EPT induced Goss orientated grains. EPT can work as a new heat treatment process for silicon steel to simultaneously obtain Goss orientated as well as fine and uniform grains, indicating the advantages of high efficiency, low energy consumption and low cost

Solution and double aging treatments of cold sprayed inconel 718 coatings

In this study, Inconel 718 coatings were deposited by the high-pressure cold spray technique, and post-process solution and double aging treatments were conducted. The microstructures of the as-deposited and heat-treated IN718 were analyzed, and their mechanical properties were tested. It was found that the micro-dendritic structures in the original powder were severely elongated in the as-deposited IN718 coating due to plastic deformation during the cold spray process. After solution heat treatment, Nb, Mo, and Ti-rich segregations could be dissolved, transforming to MC carbide and a needle-like δ phase. It was found that the needle-like δ phase at the grain boundary had a pinning effect to slow down the grain growth. In addition, strengthening phases could be formed by aging treatments. The mechanical properties of the cold sprayed Inconel 718 could be improved by proper solution and aging heat treatments.</p

Solid-state NMR spectroscopy at ultrahigh resolution for structural and dynamical studies of MOFs

To characterize the structure and dynamics of metal–-organic frameworks (MOFs) in-depth at the molecular level, it is necessary to pursue high-resolution solid-state magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. Spectral resolution is usually affected by the quality of materials and various experimental conditions, of which magic angle (MA) accuracy is a crucial determinant. The current industrial criteria for MA calibration based on the common standard of KBr were found insufficient in guaranteeing optimal resolution MAS NMR for highly ordered MOFs. To drive towards higher-resolution MAS NMR spectroscopy, we propose a calibration protocol for more accurate MA with a higher-precision criterion based on 79Br MAS NMR of KBr, where the linewidth ratio of the fifth-order spinning sideband to the central band of KBr should be less than 1.00. As a result, ultrahigh-resolution 13C cross-polarization (CP) MAS NMR of MOF-5 is achieved with minimal linewidths as low as 4 Hz, and therefore MOF-5 can be used as a new standard convenient for verifying MA accuracy and also optimizing 13C CP conditions. Maintaining high-precision MA under variable temperature (VT) was found challenging on certain commercial MAS NMR probes, as was systematically investigated by VT NMR using KBr and MOF-5. Nevertheless, ultrahigh-resolution MAS NMR spectroscopy with stable MA under VT is employed to reveal fine structures and linker dynamics of a series of Zn-based MOFs with highly regulated structures. The ultrahigh-resolution NMR methodcan be generally applied to study a broad range of MOFs and other materials