Table of Contents - Volume 15 Number 3

TiO₂ and Cu-doped TiO₂ nanoparticles (NPs) with totally extraordinary substance of Cu by exploitation hydrothermal method. The part immaculateness, morphology, molecule estimate, optical properties, and elemental composition of as-incorporated Cu-doped TiO₂ NPs were investigated by numerous systematic methods. The XRD designs unveiled Cu-doped TiO₂ NPs inside the part unadulterated anatase phase. The plane of (101) XRD and XPS results show the lucky doping of Cu²⁺ inside the TiO₂ lattice. The optical edges of Cu-doped TiO₂ demonstrated a transparent light absorption in visible region that assumes an essential part inside the photocatalytic action underneath characteristic daylight. Certain Cu²⁺ content shows least PL intensity that backings the decrease in recombination rate of charge species. In addition, to get a handle on photocatalytic action, we have tried Cu-doped TiO₂ for the degradation of Malachite Green (MG) under visible light. A large portion of 85% degradation was found for Cu-doped TiO₂ (1.71 wt.%) underneath daylight minimum of  180 min, severally, that is past that of TiO₂ (53%). Also, the degradation of the MG was affirmed by measurement of the chemical oxygen demand of the photodegraded solution. These outcomes demonstrates that the Cu-doped TiO₂ NPs are extremely productive for the photodegration of the MG.

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A new insight was watched the connection between’s the conductivity and Fourier Transform Infrared (FT-IR) spectra of the emeraldine type of polyaniline (PANI) structures. The conductivity of polyaniline emeraldine salt (PANI-ES) can be varied from 10¹ to 10^-12  S cm^-1. FT-IR spectrum is a tool to determine the conductivity level and also conductivity measuring methods of PANI system, i.e., either two probe or four probe techniques. This information is very useful for the researcher and industrialists working on emeraldine form of PANI systems to identify the conductivity level and method of measurements from FT-IR spectra. This data was seen from the infrared spectra of different PANI salts obtained by the oxidation of aniline in water/solvent medium by ammonium persulfate (APS) without utilizing any acids.  PANI-ES samples having reasonably good conductivity (> 0.3 S cm^-1) showed mostly nanowires or nanorods morphology, whereas, lower conductivity (< 0.3 S cm^-1) samples showed mostlyagglomerated spheres or particles morphology. In these investigations, however, no report was made of the use of infrared technic to determine the conductivity of PANI system.

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Spray deposited Mo-doped zinc oxide (MZO) films were grown on glass substrates at different substrate temperatures (T_s)that varied in the range of 300°C-450 °C at aconstant Mo-doping concentration of 2 at. %.XRD spectra revealed better crystallinity of films prepared atT_s400 °C. FTIR spectra showed the vibrational modes related toZn–O bonding.Photoluminescence spectra of MZO films showed a peakrelated toviolet emissionsbetween 400 nm and 420 nm. Electrical analysis showed n type semiconducting nature of the films and the films grown at T_s= 400 °C hadlow resistivity and high mobility.Adetailed analysis on theeffect of substrate temperatureon photoluminescence and electrical propertiesof MZO films wasdiscussed and reported.

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Electrospinning technique has excellent advantages such as tunable functionality, thin fibers with large surface areas, ease of processing and good physical properties. Electrospinning provides wide usage area with these advantages in biomedical applications. Polylactic acid (PLA) is a biodegradable and biocompatible polymer, so it can be used in various biomedical applications. PLA can be easily electrospun from solution by using different kinds of conventional solvents. Electrospun PLA based nanofibers are used in many biomedical applications such as drug delivery, scaffold for tissue engineering, dressings for wound healing, dental applications etc. This review focuses on electrospun PLA based nanofibers used in biomedical applications in recent years. Future perspectives of electrospun PLA based fibers are also discussed in the last part.

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The synthesis of fructose stabilize silver nanoparticles (AgNPs) was attempted in the proposed work. It was found that developed AgNPs played an important role as colorimetric nanoprobes for the estimation of metal ions. The prepared AgNPs were characterized by UV-Vis, IR, XRD, SEM techniques. XRD-pattern of AgNPs, concluded that particles are well dispersed and present in a fcc system and average size was found to be 16.6 nm. AgNPs displayed specific and sensitive recognition to Hg²⁺ by colorimetric analysis, as in the presence of Hg²⁺ ions yellow color of AgNPs solution changes to colorless. Synthesized AgNPs also play vital role in antimicrobials. Microbiological test shows that AgNPs are highly active against E.Coli and provide a safer alternative to conventional antibacterial agents. The optical florescence’s microscopy images of AgNPs shows good florescent results, which showed AgNPs with fructose capping agents, might be used as fluorescent sensing materials to sense biological materials.

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WLEDs were the potential materials for significantly improving lighting efficiency, resulting in reduction of the excitation energy and also reduction in pollution from fossil fuel power plants. To enhance the quality of white-light, the researches on single-component phosphor are very much essential. Green light emitting phosphors are widely used in solid state lighting technology. Tb³⁺ ions are doped into different hosts and they are excited by UV or NUV light to emit green light. This review presents, different hosts like silicates, oxides, phosphates and titanates based Tb³⁺ ions doped phosphor. Attempts were made to analyse preparation technique and photoluminescence characteristics of phosphors. Finally potential material among selected materials is identified for light emitting display device applications.

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Membrane gas separation technique is a promising technique for separation of gases. Nanoparticles (NPs) of hollow spherical silica were synthesized by the hydrolysis and condensation of tetramethylorthosilicate (TMOS). The nanocomposite membranes were prepared by dispersing hollow silica in hydroxyethylcellulose (HEC) polymeric solution and were cast as membranes by solution casting-solvent evaporation procedure. The % loading of NP’s in membrane varied from 0.5 to 2 Wt. %. The effects of experimental parameters such as gas permeability and selectivity at constant pressure were measured for gas transport properties for the prepared membranes. Under constant operating conditions of feed pressure (4.0 MPa) and membrane thickness (50 μm), the CO₂ permeability was determined to be in the range 1790-3620 Barrer for nanocomposite membrane from 0.5 to 2 Wt. %, while selectivity declined from 3.7 to 3.1 due to plasticization. This made us to come to the conclusion that the membrane has a double mode of sorption effect. The membranes were characterized with FTIR to confirm the formation of compound and with SEM to study the distribution of nanoparticles in the membrane matrix.

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Gold nanoparticles have attracted considerable attention due to their unique properties and potential applications as optical probes.  When proteins that are adsorbed on gold nanoparticles subsequently get cross-linked by any interaction specific to that protein, the size of the aggregates increases and this enhancement of size have been used for sensitive, convenient and powerful tool to monitor the presence of the specific cross-linkers. Dynamic light scattering (DLS) is a technique that is routinely used for detecting aggregation in macromolecular solutions. In this work, we first applied DLS to identify specific glycoprotein–lectin interactions exclusively present in the serum of hepatocellular carcinoma patients compared to healthy controls that showed the altered fucosylation of a serum protein, Serum α-1-Acid glycoprotein. Further, based on the DLS data a simple, rapid, serological assay was developed based on antibody coated gold nanoparticle and fucose binding lectin (Aleuria aurantia lectin) as linker to asses the level of fucosylation of α-1-acid glycoprotein. As a consequence of the triggered aggregation of the GNP probes in presence of lectin, plasmon band was shifted from red to blue, which colorimetrically reported the enhanced fucosylation of α-1-acid glycoprotein and formed the basis of a rapid visual assay for hepatocellular carcinoma.

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Well crystallinenanostructured TiO₂ powder was synthesised by Co-precipitation method using Titanium (IV) isopropoxide and CTAB are precursor materialsto maintain in 1:1 ratio concentration. The synthesised power was structurally, morphologically and optically analysed to using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and UV-Vis absorption spectra. The betalain pigment of polluted water was prepared from Beta vulgaris extract at room temperature (RT). The 89% of betalain pigment was degraded at 40 min from Beta vulgaris extract polluted water using as-prepared TiO₂ powder as a photocatalystmaterial under visible light.

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Green routes of synthesis are simple, safe, nontoxic and eco-friendly methods to synthesize nanoparticles of various metals and their oxides by the application of bioactive compounds of plants, algae, fungi, yeast, etc. Green engineered copper and copper oxide nanoparticles (Cu and CuO NPs) synthesis has been reported to be more economical and best alternative method among available methods. Cu and CuO NPs have been applied as dietary additives, lubricant supplements, chemical sensors, coating materials in addition to large number of biotechnological and pharmaceuticals applications. The present review aims to bring awareness about various aspects of biogenic synthesis of Cu and its oxide NPs for multifunctional applications and discusses their characterization techniques and applications in antimicrobial activity evaluation, photocatalysis, organic dye degradation, biomedical, pharmaceutical, cosmetic, energy and catalysis.

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Hydroxyapatite (HAp) is a widely explored biomaterial for bone and tooth replacements. Most of the research studies are being carried out in terms of novel routes of synthesis and fabrication in the nano scale to suit its applications. The present research study is unique in two aspects one being the use of seawaste namely Crassostreao virginica (Oyster) seashells as the source of calcium carbonate along with phosphoric acid and  in the alkaline pH to synthesize nano sized HAp and secondly to check the enhanced activity of HAp if any, upon the addition of  Azadirachta  indica Extract (neem leaf and neem stem) by wet precipitation method. The structural activity relationship of assynthesised HAp sample was compared with that of the modified HAp using Azadirachta indica extract as medium. The presence of Hexagonal phase (JCPDS no-09-0432) was identified in all HAp samples. The crystallite size of 38nm was observed in the HAP prepared from the seashell in comparison with the crystallite of 49 nm (neem leaf) and 52mm (neem stem) modified HAp. The presence of spherical morphology and elemental composition of Ca,P in HAp and modified HAps were identified from Scanning Electron Microscopic images. The toxicity studies of assynthesised HAp and modified HAp with Azadirachta indica against Candida albicans and Streptococcus mutans were compared and the results were encouraging. This study ultimately provided a simple, cost effective green method of converting seawaste into high value biomedical product of nanoscale hydroxyapatite with enhanced antimicrobial activity.

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