INVESTIGATION ON MAMMOGRAPHIC IMAGE COMPRESSION AND MICROCALCIFICATION ANALYSIS USING MULTIWAVELETS AND NEURAL NETWORKS

In digital mammography, the resulting electronic image is very large in size, which poses a significant challenge to the transmission, storage, and manipulation of images. Microcalcification is one of the earliest signs of breast cancer, and it tends to appear in small-sized, low-contrast radiopacities in the high-frequency spectrum of a mammographic image. Scalar wavelets excel multiwavelets in terms of peak-signal-to-noise ratio (PSNR), but fail to capture high-frequency information. This study proposes mammographic image compression and microcalcification detection in original and compressed reconstructed images using multiwavelets and neural networks. It also details the classification results obtained through the multiwavelet-based scheme in comparison with the existing scalar wavelet-based scheme. For a testing sample of 30 images, the proposed classification scheme outperforms the scalar wavelet-based classification by a sensitivity of 2.23% and specificity of 3.4% for original (uncompressed) images. Also, it increases the sensitivity by 2.72% and specificity by 8.4% for compressed reconstructed images. This increase in sensitivity and specificity demonstrates a better performance of the proposed detection scheme.     

Biomechanical studies on aliphatic physically crosslinked poly(urethane urea) for blood contact applications

Hydrophobic and physically crosslinked (virtually crosslinked through hydrogen bonding) aliphatic poly(urethane urea)s were developed and characterized for its biomechanical properties. The aging under induced-stress (bend samples) condition reveals resistance of poly(urethane urea) to environmental stress corrosion cracking (ESC) in hydrolytic media, Ringer's solution and phosphate buffered saline at 50 degrees C. The strain-induced (20% tensile strain) and aged polymer in hydrolytic enzyme medium, papain and in buffer reveals increase of elastic modulus in papain enzyme and papain buffer. The increase of elastic modulus is attributed to unidirectional reorganisation of chains under continually strained conditions. The polymer exposed in boiling alcoholic potassium hydroxide solution (accelerated hydrolytic chemical degradation) reveals no degradation. A comparative evaluation of poly(ether urethane urea)s reveals inferior properties. Poly(ether urethane urea)s polymer undergo hydrolytic degradation in boiling alcoholic potassium hydroxide solution. The candidate poly(urethane urea) HFL 18-PUU is more promising elastomer for long-term biomechanically sensitive blood contact applications such as heart valve and blood pump diaphragm of left ventricular assist device.     

RETRACTED ARTICLE: Medical Data Security for Healthcare Applications Using Hybrid Lightweight Encryption and Swarm Optimization Algorithm

In medical field, securing every patient’s record is main concern, ascribed to many fraudulent cases occurring in the health sector. The data of every individual must be engraved and sent into end-user without any issues. Mainly in the healthcare industry, where thoughts are often focused on saving someone’s life and rightly so, but securing access to interfaces and computer systems that store private data like medical records is also an essential factor to consider. Data security is a corresponding action between controlling access to information while allowing free and easy access to those who need that information. Still few problems are focused by the physician in the health sector. Patient’s data should be kept securely in medical provider servers so that physicians can provide proper treatments. To ensure secure storage and access management, we propose a novel hybrid lightweight encryption using swarm optimization algorithm (HLE–SO).The proposed HLE–SO technique merge Paillier encryption and KATAN algorithm, which provides the lightweight features. Generally, the lightweight encryption algorithms are affected by the key space. We introduce the swarm optimization algorithm to optimize the key space by changing the number of iteration round. Our main goal is to encrypt the medical data (EEG signal) and send to end user by utilizing proposed HLE–SO method. Finally, the implementation is done with MATLAB tool with different EEG signal data set. The simulation results of proposed HLE–SO technique is compared with the existing state-of-art techniques in terms of different performance metrics are MSE, PSNR, SSIM, PRD, encryption time and decryption time.

     

Enrichment of piezoelectric properties in Nb5+doped (0.94) (Na0.5Bi0.5)TiO3–(0.06) BaTiO3 ceramics across morphotropic phase boundary region

Lead-free piezoelectric compounds (0.94)(Na_0.5Bi_0.5)TiO₃–(0.06) BaTiO₃ [NBBT (94/06)]?+?x wt.% Nb⁵⁺ (x?=?0%, 1%, 1.5%, 2%, and 2.5%) were synthesized by the solid-state reaction route and these powders were pelletized and sintered for dielectric and piezoelectric characterization. The phase coexistence Monoclinic (Cc)?+?Rhombohedral (R3c) was affirmed using X-ray Powder diffraction analysis. The structural properties like cell parameters and space group of the synthesized ceramics were investigated by the Rietveld refinement analysis. The surface morphology and grain size of the fractured ceramics were explored using SEM imaging technique. The dielectric properties for all the ratios of NBBT (94/06) ceramics were examined using LCR meter. The piezoelectric coefficients such as d₃₃ and g₃₃ of Nb-doped NBBT (94/06) ceramics were investigated. The saturation polarization (P_s) and remanent polarization (P_r) were exhibited from the P–E hysteresis loop analysis at room temperature. The appropriate addition of Nb⁵⁺ (x?=?1.5%) in NBBT (94/06) material demonstrates eminent dielectric constant and piezoelectric coefficient d₃₃ than other wt.% of Nb. The replacement of Ti⁴⁺ with higher radius cations Nb⁵⁺ in B-site of ABO₃ composes tilting of polar BO₆ octahedra resulting in rhombohedra distortion (RD) (90° ? α), in addition, the polarizability of ions and various valance states of B-site cations could be responsible for RD (90° ? α) ensuing relatively high dielectric constant and piezoelectricity.

     

Improved mechanical and thermal properties of spent coffee bean particulate reinforced poly(propylene carbonate) composites

Using biodegradable polypropylene carbonate (PPC) as the polymer matrix and 5 to 25?wt% content of spent coffee bean powder (SCBP) as filler, completely biodegradable composite films of PPC/SCBP were prepared. These composite films were characterized by polarized optical microscopy (POM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis, differential scanning calorimetry (DSC), and tensile tests. The POM images indicated the uniform distribution of the SCBP in the composites. The FTIR spectra indicated that the PPC structure was retained by the composite films. The XRD analysis found that the composite films had lower crystallinity than the PPC due to the presence of amorphous hemicellulose containing SCBP. A significant enhancement in thermal stability of the filler reinforced composite was noticed which was more than 30% of the PPC matrix due to the presence of polyphenols in SCBP. A maximum increase of 35% of tensile strength was observed with the addition of 20?wt% SCBP filled composite films. These biodegradable composite films with higher thermal stability and tensile strength can be considered for packaging applications.     

Effect of nano ribbons formed by the amide segment on the solvent resistivity of segmented block copolymers based on polystyrene

A segmented block copolymer is synthesized using dihydroxy terminated polystyrene (PSt) (M_W = 2,500 g/mol) and crystallizable amide segments. PSt length in the copolymer is varied from 2,500 to 10,000 g/mol using dimethylterephthalate (T). Amide segment is synthesized in situ using diamine‐diamide 6X6 (X = A or T) (synthesized by dimethylterepthalate [T], adipic acid [A], and hexamethylenediamine [6]) and T. This work is to modify the high T_g amorphous PSt to a semicrystalline copolymers (‐(PSt‐T)_y‐6X6‐T‐)‐_n). These copolymers have a very high inherent viscosity and depending on the amide concentration, the melting temperature of the polymers was ranged between 129°C and 248°C. The crystallinity of the amide segments is up to 75%. The AFM analysis showed the presence of crystalline ribbons with a high aspect ratio. All the polymers show single stage decomposition temperature centered around 420°C. The solvent resistivity of these materials is very high even at a low concentration of (5 wt%) amide content. POLYM. ENG. SCI., 58:361–368, 2018. © 2017 Society of Plastics Engineers     

Interference Avoidance through Pilot‐Based Spectrum Sensing Algorithm in Overlaid Femtocell Networks

Co‐channel interference between macro–femtocell networks is an unresolved problem, due to the frequency reuse phenomenon. To mitigate such interference, a secondary femtocell must acquire channel‐state knowledge about a co‐channel macrocell user and accordingly condition the maximum transmit power of femtocell user. This paper proposes a pilot‐based spectrum sensing (PSS) algorithm for overlaid femtocell networks to sense the presence of a macrocell user over a channel of interest. The PSS algorithm senses the pilot tones in the received signal through the power level and the correlation metric comparisons between the received signal and the local reference pilots. On ensuring the existence of a co‐channel macrocell user, the maximum transmit power of the corresponding femtocell user is optimized so as to avoid interference. Time and frequency offsets are carefully handled in our proposal. Simulation results show that the PSS algorithm outperforms existing sensing techniques, even at poor received signal quality. It requires less sensing time and provides better detection probability over existing techniques.     

Influence of PVP on Bi25FeO40 microcubes for Supercapacitors and Dye-Sensitized Solar Cells applications

Journal of Materials Science: Materials in Electronics - Polyvinylpyrrolidone (PVP)-assisted Bi25FeO40 microcubes have been synthesized through hydrothermal technique and the effect of morphology...