Designing of macroporous biocompatible cryogels of PVA–haemoglobin and their water sorption study

Macroporous polymeric materials are three-dimensional porous architectures having enormous utility in the areas of biomedical, biotechnological and separation sciences. Thus realizing the crucial role of macroporous polymeric materials in tissue engineering and allied fields the present paper discusses synthesis, characterization, and blood compatibility study of macroporous cryogels of PVA and haemoglobin. Biocompatible spongy and porous hydrogels of polyvinyl alcohol–haemoglobin have been synthesized by repeated freezing–thawing method and characterized by Infrared (FTIR), and ESEM techniques. The FTIR analysis of prepared cryogels indicated that haemoglobin was introduced into the cryogel possibly via hydrogen bonds formed amongst hydroxyl groups and amino groups present in PVA and haemoglobin, respectively. The ‘cryogels’ were evaluated for their water uptake potentials and influence of various factors such as chemical architecture of the spongy hydrogels, pH and temperature of the swelling bath were investigated on the degree of water sorption by the cryogels. The hydrogels were also swollen in salt solutions and various simulated biological fluids. The effect of drying temperature on its water sorption capacity was also studied. The biocompatibility of the prepared cryogels was judged by in vitro methods of blood-clot formation, percent haemolysis and protein (BSA) adsorption.     

Polyaniline–MWCNT nanocomposites for microwave absorption and EMI shielding

Highly conducting polyaniline (PANI)–multi-walled carbon nanotube (MWCNT) nanocomposites were prepared by in situ polymerization. The FTIR and XRD show systematic shifting of the characteristic bands and peaks of PANI, with the increase in MWCNT phase, suggesting significant interaction between the phases. The SEM and TEM pictures show thick and uniform coating of PANI over surface of individual MWCNT. Based on observed morphological features in SEM, the probable formation mechanism of these composites has been proposed. The electrical conductivity of PANI–MWCNT composite (19.7 S cm^?1) was even better than MWCNT (19.1 S cm^?1) or PANI (2.0 S cm^?1). This can be ascribed to the synergistic effect of two complementing phases (i.e. PANI and MWCNT). The absorption dominated total shielding effectiveness (SE) of ?27.5 to ?39.2 dB of these composites indicates the usefulness of these materials for microwave shielding in the Ku-band (12.4–18.0 GHz). These PANI coated MWCNTs with large aspect ratio are also proposed as hybrid conductive fillers in various thermoplastic matrices, for making structurally strong microwave shields.     

Synthesis,optimization and characterization of PVA-co-poly(methacrylic acid) green adsorbents and applications in environmental remediation

Polymer Bulletin - The present paper is focused on the synthesis and optimization of a green PVA-co-poly(MAA) adsorbent by free radical polymerization using N,N′-methylene-bis-acrylamide and...     

Complexity sorting and coupled chaotic map based on 2D ECG data compression-then-encryption and its OFDM transmission with impair sample correction

Multimedia Tools and Applications - The present paper proposes a complexity sorting and coupled chaotic map mutation mechanism for compression-then-encryption of the Electrocardiogram (ECG)...     

Correlation Processor Based Sidelobe Suppression for Polyphase Codes in Radar Systems

Wireless Personal Communications - Peak sidelobe level (PSL), integrated sidelobe level (ISL) and signal to noise ratio (SNR) are the main performance indices in pulse compression radar. Pulse...     

Anomalous Jahn-Teller distortions in La0.75Ca0.25MnO3 system: An X-ray absorption study

MnK-edge X-ray absorption near edge structure (XANES) measurements have been made to study the temperature-dependent lattice effects in the La_0.75Ca_0.25MnO₃ system. The high-resolution XANES spectra recorded with high signal-to-noise ratio have allowed us to study the temperature dependence of the Jahn-Teller splitting indicated directly by the dipole forbidden pre-peaks corresponding to transition in Mn 3d states. The results show splitting of thee _g state in its two orbitals (d x² -_y ² andd _3z ²-_r ². The energy splitting shows anomalous temperature dependence across the giant magnetoresistance transition temperature.     

Stacked Gate FinFET with Gate Extension for Improved Gate Control

Russian Microelectronics - Referring to the experimental data available, a modified pile gate bulk FinFET device with trapezoidal cross-section is analyzed through this paper. Two special features...