PET image reconstruction using ANN

The aim of this study is to improve the positron emission tomography (PET) image quality for medical diagnosis. The statistical reconstructions on the maximum a posteriori (MAP) algorithm often results in a blurring effect, which fails to determine the toughness class in the reconstructed image. The development of new reconstruction algorithms for PET is an active field of research. In this article, artificial neural network (ANN) is proposed for replicating the output image, which is generated from the acquired projection data with the corresponding angles using the PET images. This article proposes the advantage of arranging the neural network to stock up the information of the continuous capacity. This reduces the storage space and recuperates as much sequence of the continuous quantity as possible. The performance of image quality parameters using ANN is better when compared with MAP, FBP‐NN (filtered back projection with nearest neighbor interpolation). Thus ANN provides 63% better peak signal to noise ratio (PSNR) when compared with FBP‐NN and 47% better when compared to MAP. Thus, ANN is better than FBP and MAP algorithm, by providing better PSNR. © 2014 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 24, 249–255, 2014     

Growth,structural, optical,thermal and mechanical properties of morpholinium 3,5-Dinitrosalicylate single crystals for nonlinear optical applications

Journal of Materials Science: Materials in Electronics - A novel third-order nonlinear optical (NLO) active organic adduct, morpholinium 3,5-dinitrosalicylic acid M35DS was synthesized and single...     

A Versatile Toolbox for Multiplexed Protein Micropatterning by Laser Lithography

Photocleavable oligohistidine peptides (POHP) allow in situ spatial organization of multiple His‐tagged proteins onto surfaces functionalized with tris(nitrilotriacetic acid) (tris‐NTA). Here, a second generation of POHPs is presented with improved photoresponse and site‐specific covalent coupling is introduced for generating stable protein assemblies. POHPs with different numbers of histidine residues and a photocleavable linker based on the 4,5‐dimethoxy‐o‐nitrophenyl ethyl chromophore are prepared. These peptides show better photosensitivity than the previously used o‐nitrophenyl ethyl derivative. Efficient and stable caging of tris‐NTA‐functionalized surfaces by POHPs comprising 12 histidine residues is demonstrated by multiparameter solid‐phase detection techniques. Laser lithographic uncaging by photofragmentation of the POHPs is possible with substantially reduced photodamage as compared to previous approaches. Thus, in situ micropatterning of His‐tagged proteins under physiological conditions is demonstrated for the first time. In combination with a short peptide tag for a site‐specific enzymatic coupling reaction, covalent immobilization of multiple proteins into target micropatterns is possible under physiological conditions.     

Effect of Molecular Rotation on Vapor Phase Nucleation: Fullerenes C60 and C70

Abstract

The effect of rotational free energy of fullerenes C₆₀ and C₇₀ on homogeneous nucleation of crystals from vapor phase have been studied. Classical nucleation parameters have been estimated for the case of nucleation and crystal growth of C₆₀ and C₇₀ by Physical Vapor Transport (PVT) method under different supercooling in the range of 20–150 K, keeping the source temperatures constant. The result shows that the growth of large size single crystals is more feasible in the lower supercooling range. The effect of change in interfacial tension on the critical free energy of formation of the nuclei is also studied.     

Microstructural, mechanical and electrochemical corrosion properties of sputtered titanium-aluminum-nitride films for bio-implants

The effect of aluminum (Al) addition to titanium nitride (TiN) matrix on the structural, mechanical and corrosion resistance properties of titanium-aluminum-nitride was studied. Ti_1−xAl_xN where x = 0, 0.5 and 1 films were coated onto substrates like Si wafer, AISI 316L stainless steel and low carbon steel by a direct current magnetron sputtering process. The layers were sputtered in pure Argon with a substrate temperature maintained at 400 °C, power of 250 W and a sputtering time of 120 min. XRD, TEM-SAED pattern and XPS analyses were made to study the structural properties of these films. Laser Raman spectrum showed the characteristic peaks at 249 and 659 cm⁻¹ for the Ti_0.5Al_0.5N film. AFM analysis showed a relatively smooth surface for the ternary film. Corrosion performance analysis indicated that the Ti_0.5Al_0.5N coated specimen had superior corrosion resistance when compared to TiN and AlN coated substrates. Higher values of nanohardness and lower coefficient of friction were observed for the Ti _0.5Al_0.5N specimen. Blood platelet adhesion experiments were made to examine the interaction between human blood and the materials in vitro.     

Processing,structure and flexural strength of CNT and carbon fibre reinforced,epoxy-matrix hybrid composite

Advanced materials such as continuous fibre-reinforced polymer matrix composites offer significant enhancements in variety of properties, as compared to their bulk, monolithic counterparts. These properties include primarily the tensile stress, flexural stress and fracture parameters. However, till date, there are hardly any scientific studies reported on carbon fibre (C_f) and carbon nanotube (CNT) reinforced hybrid epoxy matrix composites (unidirectional). The present work is an attempt to bring out the flexural strength properties along with a detailed investigation in the synthesis of reinforced hybrid composite. In this present study, the importance of alignment of fibre is comprehensively evaluated and reported. The results obtained are discussed in terms of material characteristics, microstructure and mode of failure under flexural (3-point bend) loading. The study reveals the material exhibiting exceptionally high strength values and declaring itself as a material with high strength to weight ratio when compared to other competing polymer matrix composites (PMCs); as a novel structural material for aeronautical and aerospace applications.     

Effect of reinforced fiber length on the joint performance of thermoplastic leaf spring

Joint strength plays a significant role in the performance of leaf spring suspension system. Current work reported the influence of reinforced fiber length on the performance of injection molded thermoplastic leaf spring joint. Leaf springs were molded using 20% short, long glass fiber reinforced polypropylene as well as unreinforced polypropylene and evaluated for the joint strength. Servo hydraulic test facility with suitable fixture is utilized to evaluate the leaf spring joint performance under static and dynamic conditions. Test joints were subjected to completely reversed fatigue loads, wherein long fiber reinforced leaf spring joint exhibited superior performance at high cycle fatigue conditions than that of short fiber reinforced and unreinforced polypropylene leaf spring joints. However, at low cycle fatigue loading conditions, unreinforced and short glass fiber reinforced leaf spring exhibited superior performance than that of long glass fiber reinforced leaf spring joint. High notch sensitivity characteristics of the long glass fiber reinforced polypropylene material contributed to this inferior performance. Load–deflection hysteresis plot of the long glass fiber reinforced leaf spring joint under fatigue loading conditions exhibited a lesser amount of hole elongation compared to that of short glass fiber and unreinforced leaf spring joint. Failure morphology of tested joint under fatigue condition exhibited net-tension and shear-out failures besides bearing damages.     

Scalable vertical diaphragm pressure sensors: device and process Design, Design for packaging

We present a design, process How, and packaging scheme for a novel three-dimensional capacitive microelectromechanical systems pressure sensor [1], [10]. These sensors present a paradigm shift in pressure sensor technology. They contain an array of vertical diaphragms perpendicular to the wafer plane where each pair of diaphragms requires orders of magnitude lower footprint than traditional in-plane sensors. The sensor can be arrayed or scaled up for increased sensitivity and can be absolute, gauge or differential. Fabrication requires 2-4 masks, depending on process How and has been greatly simplified, without reduction in performance, for high yield and low cost. Multiple geometries have been modeled with sensitivities reaching several fF/kPa and temperature coefficient of sensitivity better than conventional devices. Pressure and electrical ports are individually interchangeable between front and back sides. This allows for a simple design that has only Si facing the sensing environment and the electrical connections on the backside, thus enabling simple packaging for both pressure and electrical ports.     

Adsorption of trace elements from poultry litter by montmorillonite clay

Poultry litter (PL) is used as fertilizer on agricultural lands because of its high nutrient content. However, the litter also contains trace elements such as As, Cd, Cu, Pb, and Zn. On land application of PL, these trace elements may be absorbed by crops, leach into groundwater, or enter the aquatic system as run-off. The objective of this research was to study the effect of the addition of montmorillonite clay-mineral (CM) in reducing the release of trace elements from PL. Cd, Cu, and Zn showed significant decreases of 29, 34, and 22%, respectively, in PL aqueous leachate (compared with the control-PL without CM) on mixing with 0.05 g CM but no change in As, Co, and Cr concentrations was observed. Lead showed a significant increase in PL aqueous leachate on mixing with 0.2 g CM but Pb concentration was two orders of magnitude less than in CM aqueous leachate alone. On washing, the settled precipitate (PL+CM) in the centrifuge tubes with water (desorption study) most of the adsorbed metals (Cd 85%, Cu 61%, and Zn 100%) were released. The results of this study show that the addition of CM resulted in significant adsorption of Cd and Cu from PL.     

A single exposure reflection moiré interferometric technique for complete curvature analysis of bent plates

Most known moiré methods need to be repeated three times for getting curvature information in three different in plane directions, for the complete analysis. To overcome this difficulty, a new single exposure moiré interferometric technique is proposed that maps completely partial curvature contours in three different directions of laterally loaded specularly reflecting plate models. Converging HeNe laser light is diffracted by a lens plane cross grating. The 00, + 10 and the +01 diffraction orders are permitted through the Fourier transform (FT) plane and collimated to illuminate the plate model. The reflected light from the loaded model records the model with the inherent deformed interferometric cross grating superimposed on it. A posteriori Fourier filtering of the developed recording (moirégram) gives partial curvature contours pertaining to three different in plane directions from which the principal curvatures and the principal directions are obtained. Also, this technique, being a single exposure technique, has the potential for complete bending analysis of plates subjected to lateral impact loading and destructive loading applications, where the repeatability of the event may not be possible.