Angiotensin converting enzyme inhibition, AT1 receptor inhibition, and combination therapy with pacing induced heart failure: effects on left ventricular performance and regional blood flow patterns

BACKGROUND: AT1 receptor activation has been demonstrated to cause increased vascular resistance properties which may be of particular importance in the setting of congestive heart failure (CHF). The overall goal of this study was to examine the effects of ACE inhibition (ACEI) alone, AT1 receptor blockade alone and combined ACEI and AT1 receptor blockade on LV pump function, systemic hemodynamics and regional blood flow patterns in the normal state and with the development of pacing induced CHF, both at rest and with treadmill induced exercise. METHODS AND RESULTS: Pigs (25 kg) were instrumented in order to measure cardiac output (CO), systemic (SVR) and pulmonary vascular (PVR) resistance, neurohormonal system activity, and myocardial blood flow distribution in the conscious state and assigned to one of 4 groups: (1) rapid atrial pacing (240 bpm) for 3 weeks (n = 7); (2) ACEI (benazeprilat, 3.75 mg/day) and pacing (n = 7); (3) AT1 receptor blockade (valsartan, 60 mg/day) and rapid pacing (n = 7); and (4) ACEI and AT1 receptor blockade (benazeprilat/valsartan, 1/60 mg/day, respectively) and pacing (n = 7). Measurements were obtained at rest and with treadmill exercise (15 degrees, 3 miles/h; 10 min) in the normal control state and after the completion of the treatment protocols. With rapid pacing, CO was reduced at rest and with exercise compared to controls. ACEI or AT1 blockade normalized CO at rest, but remained lower than control values with exercise. Combination therapy normalized CO both at rest and with exercise. Resting SVR in the CHF group was higher than controls and SVR fell to a similar degree with exercise; all treatment groups reduced resting SVR. With exercise, SVR was reduced from rapid pacing values in the ACEI and combination therapy groups. PVR increased by over 4-fold in the rapid pacing group both at rest and with exercise, and was reduced in all treatment groups. In the combination therapy group, PVR was similar to control values with exercise. Plasma catecholamines and endothelin levels were increased by over 3-fold with chronic rapid pacing, and were reduced in all treatment groups. In the combination therapy group, the relative increase in catecholamines and endothelin with exercise were significantly blunted when compared to rapid pacing only values. LV myocardial blood flow at rest was reduced in the rapid pacing only and monotherapy groups, but was normalized with combination therapy. CONCLUSION: These findings suggest that with developing CHF, combined ACE inhibition and AT1 receptor blockade improved vascular resistive properties and regional blood flow distribution to a greater degree than that of either treatment alone. Thus, combined ACEI and AT1 receptor blockade may provide unique benefits in the setting of CHF.     

High Performance VLSI Architecture for Three-Step Search Algorithm

Motion estimation is the most computationally intensive part of any video coding standard. The three-step search algorithm is a popular fast search technique to reduce complexity in motion estimation. In this paper, we propose a novel architecture for the three-step search technique that simplifies memory addressing and reduces hardware complexity. The proposed architecture minimizes the area while maintaining the speed requirements for real-time video processing. Implemented in Verilog HDL on Virtex-5 technology and synthesized using Xilinx ISE Design Suite 14.1, the critical path in the hardware is 6.536 ns and the equivalent area is calculated to be 2.3 K gate equivalent.     

Improvement of the physico‐mechanical properties and stability of waste polypropylene in the presence of wood flour and (maleic anhydride)‐grafted polypropylene

This paper deals with (maleic anhydride)‐grafted polypropylene (MAH‐g‐PP) and wood flour reinforcement and their effects on the dynamic, mechanical, morphological, and rheological properties of waste polypropylene (PP) composites. MAH‐g‐PP was used as a compatibilizer to improve the physical interaction between the filler and matrix. The composites were prepared by using a twin‐screw extruder followed by injection molding. Thermal stability and mechanical properties of the compatibilized system increased as compared to their values for the uncompatibilized system. Also, nearly 60% and 30% loss was found for mechanical properties and weight loss, respectively, in a biodegradability study. J. VINYL ADDIT. TECHNOL., 20:24–30, 2014. © 2014 Society of Plastics Engineers     

The influence of TiO2 content on the properties of glass ceramics: Crystallization,microstructure and hardness

The effects of compositional variation, crystallization behavior, crystalline phases and microstructure formed in the SiO₂3Al₂O₃3CaO (SAC) glass system using various amounts of TiO₂ as nucleating agent were investigated by Differential Thermal Analysis (DTA), X-ray powder diffraction (XRD), Scanning Electron Microscope (SEM), Energy-dispersive X-ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR) techniques. The crystallization kinetics and mechanical properties of SAC glass ceramics were studied using crystallization peak temperature (T_p) of three different glasses as obtained from DTA, the activation energy (E) and Avrami exponent (n) were also determined. The crystallization peak temperature (T_p) and activation energy (E) were found to increase with the increase in TiO₂ content. The major crystalline phases were anorthite and wollastonite along with gehlenite and titanite as the minor crystalline phases present in the glass ceramic system. The studies showed that the three dimensional crystalline structure and the microhardness increased with the increase of TiO₂ content in the glass ceramics system.     

Tunable Luminescent Carbon Nanospheres with Well‐Defined Nanoscale Chemistry for Synchronized Imaging and Therapy

In this work, we demonstrate the significance of defined surface chemistry in synthesizing luminescent carbon nanomaterials (LCN) with the capability to perform dual functions (i.e., diagnostic imaging and therapy). The surface chemistry of LCN has been tailored to achieve two different varieties: one that has a thermoresponsive polymer and aids in the controlled delivery of drugs, and the other that has fluorescence emission both in the visible and near‐infrared (NIR) region and can be explored for advanced diagnostic modes. Although these particles are synthesized using simple, yet scalable hydrothermal methods, they exhibit remarkable stability, photoluminescence and biocompatibility. The photoluminescence properties of these materials are tunable through careful choice of surface‐passivating agents and can be exploited for both visible and NIR imaging. Here the synthetic strategy demonstrates the possibility to incorporate a potent antimetastatic agent for inhibiting melanomas in vitro. Since both particles are Raman active, their dispersion on skin surface is reported with Raman imaging and utilizing photoluminescence, their depth penetration is analysed using fluorescence 3D imaging. Our results indicate a new generation of tunable carbon‐based probes for diagnosis, therapy or both.     

Development of catalytic activity protocol for electrochemical reduction of carbon dioxide to value added products

Utilization of carbon dioxide for the production of value added products is a challenging task. Electrochemical reduction of carbon dioxide is one of the most promising techniques to convert the carbon dioxide into value added products. However, the development and selection of a suitable electrocatalyst is not so straightforward. The main problems are non-selectivity of the electrocatalyst toward CO₂ reduction, simultaneous hydrogen evolution reaction, and low efficiency of the process. To overcome these problems, many electrocatalysts have been studied and reported in the literature. However, there is no effective guideline to screen the electrocatalysts in a quick and simple way. Moreover, it is found that the method used for the screening of electrocatalyst is not accurate and has anomalies. Therefore, in this paper, a simple and quick protocol based on half-cell tests is proposed. The method provides a first-hand prediction about the electrochemical activity of an electrocatalyst toward electrochemical reduction of carbon dioxide. The protocol was validated and compared along with confirming the results by product analysis of the electrochemical reduction of CO₂ using full electrochemical reactor. The method was found satisfactory for the preliminary screening of electrocatalyst to reduce carbon dioxide electrochemically.     

Compatibility Issues of Yttria‐Stabilized Zirconia Solid Oxide Membrane in the Direct Electro‐Deoxidation of Metal Oxides

Direct electro‐deoxidation of metal oxides has become quite popular in the production of metals and alloys. In this process, metal oxide cathode is directly reduced to a metal in a molten CaCl₂ salt bath. The anode material used is graphite. Over the years, graphite is reported to cause numerous process difficulties. Recently, based on the solid oxide membrane technology, yttria‐stabilized zirconia (YSZ) has been tested as oxygen ion conducting membrane for the anode. The success of using a membrane implies its long‐term stability in the bath. In this paper, it is seen that YSZ chemically degrades in a static melt of CaCl₂ or CaCl₂–CaO. The degradation occurs by leaching of yttria into solution leading to the formation of monoclinic zirconia which, being porous, reacts with the molten electrolyte to form calcium zirconate. However, on application of voltage, YSZ degrades via a different mechanism. The metallic calcium produced during electrolysis increases the electronic conductivity of the salt, apparently leading to the electrochemical reduction of zirconia to ZrO_2?x. As a result, localized pores are formed which allow the infiltration of salts. Addition of yttria to the salt is seen to prevent both the chemical and electrochemical degradation of the membrane.     

Hierarchically Ordered Nano‐Heterostructured PZT Thin Films with Enhanced Ferroelectric Properties

Realization of ferroelectric (FE) devices based on the polarization effects of Pb(Zr_0.52Ti_0.48)O₃ (PZT) has reinforced the investigation of this material in multiple dimensions and length scales. Multi‐level hierarchical nanostructure engineering in PZT thin films offer dual advantages of variable length‐scale and dimensionality. Here, the growth of hierarchically ordered PZT nano‐hetero­structures (Nhs) from PZT seed‐layer deposited on SrTiO₃:Nb (100) substrates, using a physical/chemical combined methodology involving pulsed laser deposition (PLD) and hydrothermal processes, is reported. Systematic SEM, TEM, and Raman spectroscopy studies reveal mixed hetero‐ and homo‐epitaxial growth mechanism. In the final stage, 3D Nh units cross‐link and form a dense network‐like Nh PZT thin‐film. FE polarizations are measured without using any polymer fill‐layer which otherwise introduces huge dielectric losses and lowers the polarization values for a FE device. In benefit, well saturated and symmetric FE hysteresis loops are observed with high degree of squareness and a high remnant polarization (54 μC cm^‐2 at a coercive field of 237 kV cm^‐1). This work provides a pathway towards preparing hierarchical PZT Nhs offering coherent design of high‐performance FE capacitors for data storage technologies in future.