Journal of Nanoparticles The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Synthesis and Investigation of Antimicrobial Activity of Cu2O Nanoparticles/Zeolite Mon, 09 Jan 2017 10:57:58 +0000 Cuprous oxide (Cu2O) nanoparticles in zeolite A were synthesized by two steps: (i) ion-exchange of copper ions into the zeolite and (ii) reduction of copper ions in cages of the zeolite by hydrazine hydrate in base medium. The Cu2O nanoparticles/zeolite product was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The particle size of Cu2O nanoparticles was of 40 nm. The antibacterial activity of the as-synthesized Cu2O nanoparticles/zeolite against Escherichia coli was also investigated. Cu2O NPs/zeolite product can be favorably produced on large scale for water treatment and agricultural application as antimicrobial agent. Bui Duy Du, Dang Van Phu, Le Anh Quoc, and Nguyen Quoc Hien Copyright © 2017 Bui Duy Du et al. All rights reserved. Synthesis and Characterization of Cockle Shell-Based Calcium Carbonate Aragonite Polymorph Nanoparticles with Surface Functionalization Sun, 01 Jan 2017 09:26:00 +0000 The development of cockle shell-based calcium carbonate aragonite polymorph nanoparticle synthesis method using the technique of mechanical stirring in the presence of dodecyl dimethyl betaine (BS-12) incorporated with surface functionalization demonstrated high homogeneity of sample product with good nanoparticles dispersion. The cockle shell-based calcium carbonate aragonite nanoparticle with functionalized surface was characterized using transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), particle size distribution, pH measurement analysis, Fourier Transform Infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). Surface functionalization was proven to improve the overall size and shape of the nanoparticles and enhance their dispersion properties, preventing coarse agglomeration among nanoparticles in general. The improved method was verified to retain its aragonite crystalline nature. Additionally, surface functionalization did not increase the size of nanoparticles throughout the modification process. This facile preparation using naturally occurring cockle shells as the main source is environmentally friendly because it provides relatively low cost of raw material source as it is abundantly available in nature and has good mineral purity content. Hence, high quality production of surface functionalized cockle shell-based calcium carbonate aragonite polymorph nanoparticles can potentially be exploited and produced on a large scale for various industrial applications, especially for biomedical purposes in the near future. Syairah Liyana Mohd Abd Ghafar, Mohd Zobir Hussein, and Zuki Abu Bakar Zakaria Copyright © 2017 Syairah Liyana Mohd Abd Ghafar et al. All rights reserved. Dispersion of Titanium Oxide Nanoparticles in Aqueous Solution with Anionic Stabilizer via Ultrasonic Wave Thu, 24 Nov 2016 10:10:02 +0000 This paper aims to reveal the effects of odium hexametaphosphate (SHMP) and polyacrylic acid (PAA) on dispersion of TiO2 (P25) nanopowder in de-ionic water through ultrasonic horn. We characterized TiO2 suspension by transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), zeta potential, and surface contact angle instruments. As shown in the results, particularly, it were noticed that (1) the SHMP has better dispersion than PAA due to electronegativity effect, resulting in that the average particle size of the dispersed titanium dioxide in de-ionic water was roughly 92 nm, and (2) the zeta potential of TiO2 suspension with SHMP can be achieved by 54 mV at pH value of 7.7, causing stronger electrostatic repulsion in the suspension solution, compared with PAA. Wen-Bin Tsai, Jui-Yang Kao, Tzong-Ming Wu, and Wen-Tung Cheng Copyright © 2016 Wen-Bin Tsai et al. All rights reserved. Effect of Uniformly and Nonuniformly Coated Al2O3 Nanoparticles over Glass Tube Heater on Pool Boiling Tue, 15 Nov 2016 09:05:32 +0000 Effect of uniformly and nonuniformly coated Al2O3 nanoparticles over plain glass tube heater on pool boiling heat transfer was studied experimentally. A borosilicate glass tube coated with Al2O3 nanoparticle was used as test heater. The boiling behaviour was studied by using high speed camera. Result obtained for pool boiling shows enhancement in heat transfer for nanoparticle coated surface heater and compared with plain glass tube heater. Also heat transfer coefficient for nonuniformly coated nanoparticles was studied and compared with uniformly coated and plain glass tube. Coating effect of nanoparticles over glass tube increases its surface roughness and thereby creates more nucleation sites. Nitin Doifode, Sameer Gajghate, Abdul Najim, Anil Acharya, and Ashok Pise Copyright © 2016 Nitin Doifode et al. All rights reserved. Vitis vinifera Assisted Silver Nanoparticles with Antibacterial and Antiproliferative Activity against Ehrlich Ascites Carcinoma Cells Wed, 17 Aug 2016 16:50:09 +0000 Vitis vinifera extract assisted silver nanoparticles (AgNPs) were biosynthesized that was confirmed primarily by color change and a sharp plasmon absorption band was found at 449 nm. Biosynthesized AgNPs shape was spherical and the particle size of 17 nm in average was confirmed by transmission electron microscopy (TEM) images. Functional groups of AgNPs were identified by Fourier transform infrared spectroscopy (FTIR). Streptococcus aureus was the most sensitive bacteria towards the assisted V. vinifera AgNPs as their growth was 90% inhibited at 100 μg/mL concentration. That was also confirmed by the zone of inhibition study. Up to 96 h, no biofilm was observed for K. pneumoniae at 40 μg/mL of AgNPs. Although AgNPs showed a mild toxicity against brine shrimp nauplii, it showed a remarkable level of antiproliferative activity against Ehrlich ascites carcinoma (EAC) cells. A. K. M. Asaduzzaman, Byung-Soo Chun, and Syed Rashel Kabir Copyright © 2016 A. K. M. Asaduzzaman et al. All rights reserved. A Thermofluid Analysis of the Magnetic Nanoparticles Enhanced Heating Effects in Tissues Embedded with Large Blood Vessel during Magnetic Fluid Hyperthermia Mon, 18 Apr 2016 11:58:17 +0000 The thermal effect developed due to the heating of magnetic nanoparticles (MNPs) in presence of external magnetic field can be precisely controlled by the proper selection of magnetic absorption properties of the MNPs. The present paper deals with the numerical simulation of temperature field developed within or outside the tumor, in the presence of an external alternating magnetic field, using a thermofluidic model developed using ANSYS FLUENT®. A three-layer nonuniform tissue structure with one or two blood vessels surrounding the tumor is considered for the present simulation. The results obtained clearly suggest that the volumetric distribution pattern of MNPs within the tumor has a strong influence on the temperature field developed. The linear pattern of volumetric distribution has a strong effect over the two other types of distribution considered herein. Various other important factors like external magnetic field intensity, frequency, vascular congestion, types of MNP material, and so forth are considered to find the influence on the temperature within the tumor. Results show that proper selection of these parameters has a strong influence on the desired therapeutic temperature range and thus it is of utmost importance from the efficacy point of view of magnetic fluid hyperthermia (MFH). Koustov Adhikary and Moloy Banerjee Copyright © 2016 Koustov Adhikary and Moloy Banerjee. All rights reserved. Improved Synthesis of Nanosized Silica in Water-in-Oil Microemulsions Wed, 09 Mar 2016 13:23:38 +0000 Present contribution describes modified Stöber synthesis of silica nanoparticles in oil-in-water microemulsion, formulated using heptane, 2-ethylhexanol, Tween® 85 nonionic surfactant, and tetraethyl orthosilicate (TEOS). After some specified incubation time, ammonium hydroxide was added and the reaction mixture was stirred for 24 hours at room temperature. Prior to synthesis, pseudoternary diagram was created for oil-rich area and Winsor IV region was identified. These microemulsions were used for synthesis of silica particles. Resulting particles were characterized by dynamic light scattering, electrokinetic measurements, specific surface area measurements, and powder diffraction. Particles’ diameter was ranging between ca. 130 and 500 nm; usually monodisperse distribution was obtained. The specific surface area of nanoparticles was ranging between 250 and 300 m2/g. Notably, productivity per unit volume of solution was 3 to 5 times higher than for previously reported procedures. Our method can be extended, because polymeric materials can be added to dispersed aqueous phase. In our studies, β-cyclodextrin and hydroxyethylcellulose have been used, giving particles between 170 and 422 nm, with the surface area larger than 300 m2/g. Tomasz Koźlecki, Izabela Polowczyk, Anna Bastrzyk, and Wojciech Sawiński Copyright © 2016 Tomasz Koźlecki et al. All rights reserved. Screening Antimicrobial Activity of Nickel Nanoparticles Synthesized Using Ocimum sanctum Leaf Extract Thu, 03 Mar 2016 12:42:37 +0000 Antimicrobial efficacy of nickel nanoparticles synthesized using leaf extract of Ocimum sanctum (NiGs) was investigated against pathogenic Gram-negative (E. coli, K. pneumoniae, and S. typhi), Gram-positive (B. subtilis, S. epidermidis) bacteria and fungi (C. albicans, C. tropicalis, A. fumigatus, A. clavatus, and A. niger). 100 µg/mL NiGs showed maximum antimicrobial activity against tested pathogens compared to leaf extract and antibiotics. E. coli (25 mm) and C. albicans (23 mm) exhibited higher zone of inhibition at 100 µg/mL NiGs. MIC, MBC, and MFC values of NiGs against all tested pathogens ranged between 25 and 50 µg/mL. Growth of bacterial and fungal cells (105 cfu/mL) was completely inhibited at 50 µg/mL NiGs. E. coli and C. albicans have showed strong antimicrobial activity with 81% and 50% reactive oxygen species (ROS) production, 30 and 16 µg/mL protein leakage, and 95 and 82 U/L LDH leakages, respectively. Gram-negative bacteria and Candida species showed more sensitivity to NiGs at all concentrations tested (25–100 µg/mL) than Gram-positive bacteria and Aspergillus species, respectively. Microbial growth in the presence of NiGs and ascorbic acid confirmed the involvement of ROS in antimicrobial activity. Hence, NiGs induced ROS generation was attributed to the protein and LDH leakage from microbial membranes. Chitra Jeyaraj Pandian, Rameshthangam Palanivel, and Solairaj Dhanasekaran Copyright © 2016 Chitra Jeyaraj Pandian et al. All rights reserved. Synthesis, Characterization, and Photocatalytic Performance of Mesoporous α-Mn2O3 Microspheres Prepared via a Precipitation Route Sun, 21 Feb 2016 07:24:32 +0000 α-Mn2O3 microspheres with high phase purity, crystallinity, and surface area were synthesized by the thermal decomposition of precipitated MnCO3 microspheres without the use of any structure directing agents and tedious reaction conditions. The prepared Mn2O3 microspheres were characterized by Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) and photoluminescence (PL) studies. The complete thermal transformation of MnCO3 to Mn2O3 was clearly shown by the FTIR and XRD analysis. The electron microscopic images clearly confirmed the microsphere-like morphology of the products with some structural deformation for the calcined Mn2O3 sample. The mesoporous texture generated from the interaggregation of subnanoparticles in the microstructures is visibly evident from the TEM and BET studies. Moreover, the Mn2O3 microstructures showed a moderate photocatalytic activity for the degradation of methylene blue dye pollutant under UV light irradiation, using air as the potential oxidizing agent. Manoj Pudukudy and Zahira Yaakob Copyright © 2016 Manoj Pudukudy and Zahira Yaakob. All rights reserved. Structural, Electrical, Dielectric, and Magnetic Properties of Cd2+ Substituted Nickel Ferrite Nanoparticles Wed, 10 Feb 2016 13:52:03 +0000 In the present investigation structural, electric, magnetic, and frequency dependent dielectric properties of ferrite nanoparticles (NPs) (where , , , and 0.8) prepared by sol-gel autocombustion method were studied. The crystallite size () (46.89~58.40 nm) was estimated from X-ray diffraction data with the postconfirmation of single phase spinel structure. Spherical shaped, fused grain nature with intergranular diffusion in NPs was observed in scanning electron micrographs. The value of loss tangent () decreases exponentially with an increasing frequency indicating normal Maxwell-Wagner type dielectric dispersion due to interfacial polarization. Decreasing values of Curie temperature () from 860°C to 566°C with increasing Cd2+ content in NPs were determined from AC-Susceptibility. Activation energy ranges within 0.03~0.15 eV. Decreasing magnetic saturation , coercivity , and magneton number values show the effect on nonmagnetic Cd2+ ions over magnetic Ni2+ and Fe ions. B. H. Devmunde, A. V. Raut, S. D. Birajdar, S. J. Shukla, D. R. Shengule, and K. M. Jadhav Copyright © 2016 B. H. Devmunde et al. All rights reserved. Hydrophobic Coatings Composed by Cubic-Shaped CdO Nanoparticles Grown by a Novel and Simple Microwave Method Wed, 27 Jan 2016 12:40:19 +0000 Cube-shaped cadmium oxide (CdO) nanoparticles were deposited by a novel low cost microwave evaporation technique. High purity cadmium (Cd) flakes were placed in a microwave susceptor inside a commercial microwave oven. Metallic Cd was evaporated in less than 2 minutes and it was oxidized due to ambient oxygen. The CdO nanoparticles were deposited on a glass substrate placed few centimeters above the susceptor. The surfaces with nanoparticles were treated with a solution containing ethanol and phenyltriethoxysilane (PTES), and the hydrophobic properties of the as-synthesized and post-PTES-treated surfaces were studied. Morphological and structural information of the as-synthesized nanoparticles were investigated via SEM and XRD analysis. Contact angles () for the as-synthesized CdO surfaces were about 112°, whereas, for ethanol/PTES-treated CdO nanoparticles surfaces, contact angles were improved to about 158°. Thus, ethanol/PTES-treated CdO nanoparticles obtained by this simple procedure showed superhydrophobicity properties of potential use in micro fluidic devices and some other applications in the future. Mehrdad Rashidzadeh, Guillermo Carbajal-Franco, and Arturo Tiburcio-Silver Copyright © 2016 Mehrdad Rashidzadeh et al. All rights reserved. Retracted: Green Chemistry Approach for Efficient Synthesis of Schiff Bases of Isatin Derivatives and Evaluation of Their Antibacterial Activities Thu, 17 Dec 2015 09:31:17 +0000 Journal of Nanoparticles Copyright © 2015 Journal of Nanoparticles. All rights reserved. Retracted: Role of Surfactant in the Formation of Gold Nanoparticles in Aqueous Medium Thu, 17 Dec 2015 09:22:37 +0000 Journal of Nanoparticles Copyright © 2015 Journal of Nanoparticles. All rights reserved. Retracted: Plasmonic and Thermooptical Properties of Spherical Metallic Nanoparticles for Their Thermoplasmonic and Photonic Applications Thu, 17 Dec 2015 09:21:23 +0000 Journal of Nanoparticles Copyright © 2015 Journal of Nanoparticles. All rights reserved. Ammonia Sensing by PANI-DBSA Based Gas Sensor Exploiting Kelvin Probe Technique Tue, 17 Nov 2015 07:25:28 +0000 Dodecyl benzene sulfonic acid (DBSA) doped polyaniline (PANI-DBSA) has been synthesized by chemical oxidative polymerization of aniline monomer in the presence of DBSA. The UV-visible spectroscopy and X-ray diffraction measurements confirm the formation of PANI and its doping by DBSA. SEM images show the formation of submicron size rod shaped PANI particles. A vibrating capacitor based ammonia gas sensor was prepared by spin coating PANI-DBSA film over copper (Cu) substrate. The sensor exploited Kelvin probe technique to monitor contact potential difference between PANI and Cu as a function of time and ammonia concentration. Upon exposure to 30 ppm ammonia, the sensor displays response time of 329 s, recovery time of 3600 s, and sensitivity value of 1.54 along with good repeatability. Anju Yadav, Ajay Agarwal, Pankaj B. Agarwal, and Parveen Saini Copyright © 2015 Anju Yadav et al. All rights reserved. Effect of Microbes on the Adsorption of Naphthalene by Graphene Oxide Mon, 28 Sep 2015 11:49:03 +0000 The adsorption of naphthalene on graphene oxide (GO) nanosheets in presence of Paecilomyces cateniannulatus (P. cateniannulatus) was conducted by the batch techniques. The morphology and nanostructure of GO were characterized by SEM, TEM, FTIR, XPS, and Raman. The adsorption kinetics indicated that the adsorption of naphthalene on GO and GO + P. catenlannulatus can be satisfactorily fitted pseudo-first-order and pseudo-second-order kinetic model, respectively. P. catenlannulatus inhibited the adsorption of naphthalene on GO at , whereas the increased adsorption was observed at . The adsorption of naphthalene on GO and GO + P. catenlannulatus can be better fitted by Langmuir and Freundlich model, respectively. The change in the conformation of GO was responsible to the increased adsorption of naphthalene by SEM and TEM images. According to FTIR analysis, naphthalene was absorbed by the oxygen-containing functional groups of GO, especially for –COOH. The finding in the study provides the implication for the preconcentration and removal of polycyclic aromatic hydrocarbons from environment cleanup applications. Xiaoyu Li, Fengbo Li, and Lejin Fang Copyright © 2015 Xiaoyu Li et al. All rights reserved. Novel Electrochemical Synthesis of Polypyrrole/Ag Nanocomposite and Its Electrocatalytic Performance towards Hydrogen Peroxide Reduction Mon, 21 Sep 2015 12:10:54 +0000 A simple electrochemical method of synthesis of polypyrrole/silver (PPy/Ag) nanocomposite is presented. The method is based on potentiodynamic polymerization of pyrrole followed by electrodeposition of silver employing a single potentiostatic pulse. The synthesized PPy film has embedded Ag nanocubes. The morphology and structure of the resulting nanocomposite were characterized by field emission scanning electron microscopy and X-ray diffraction. Electron paramagnetic resonance studies showed that silver nanoparticle deposition on polypyrrole leads to an increase in carrier density, indicative of enhanced conductivity of the resulting composite. Electrocatalytic performance of the prepared composite was examined for reduction of hydrogen peroxide and was compared with corresponding PPy film and bare glassy carbon electrode. Ruma Gupta, Kavitha Jayachandran, J. S. Gamare, B. Rajeshwari, Santosh K. Gupta, and J. V. Kamat Copyright © 2015 Ruma Gupta et al. All rights reserved. Generation Control of ZnO Nanoparticles Using a Coaxial Gas-Flow Pulse Plasma Ar/O2 Plasma Mon, 07 Sep 2015 11:58:40 +0000 Generation of ZnO nanoparticles was investigated using a coaxial gas-flow pulse plasma. We studied how zinc atoms, sputtered from a zinc target, reacted with oxygen in a plasma and/or on a substrate to form ZnO nanoparticles when the discharge parameters, such as applied pulse voltage and gas flow rate, were controlled in an O2/Ar plasma. The formation processes were estimated by SEM, TEM, and EDX. We observed many ZnO nanoparticles deposited on Si substrate. The particle yield and size were found to be controlled by changing the experimental parameters. The diameter of the particles was typically 50–200 nm. Hiroki Shirahata and Satoru Iizuka Copyright © 2015 Hiroki Shirahata and Satoru Iizuka. All rights reserved. Synthesis and Characterization of Nanocrystalline Ni50Al50−xMox (x = 0–5) Intermetallic Compound during Mechanical Alloying Process Thu, 03 Sep 2015 08:32:16 +0000 Nanocrystalline (, 0.5, 1, 2.5, 5) intermetallic compound was produced through mechanical alloying of nickel, aluminum, and molybdenum powders. Powders produced from milling were analyzed using scanning electron microscopy (SEM) and X-ray diffractometry (XRD). Results showed that, with increasing the atomic percent of molybdenum, average grain size decreased from 3 to 0.5 μm. Parameter lattice and lattice strain increased with increasing the atomic percent of molybdenum, while the crystal structure became finer up to 10 nm. Also, maximum microhardness was obtained for NiAl49Mo1 alloy. A. Khajesarvi and G. H. Akbari Copyright © 2015 A. Khajesarvi and G. H. Akbari. All rights reserved. Nano/Microstructured Materials 2014 Sun, 28 Jun 2015 08:00:20 +0000 Amir Kajbafvala, Hamed Bahmanpour, Ali Moballegh, Mohammad H. Maneshian, and Hamid Reza Zargar Copyright © 2015 Amir Kajbafvala et al. All rights reserved. Modulatory Effect of Citrate Reduced Gold and Biosynthesized Silver Nanoparticles on α-Amylase Activity Tue, 23 Jun 2015 12:24:00 +0000 Amylase is one of the important digestive enzymes involved in hydrolysis of starch. In this paper, we describe a novel approach to study the interaction of amylase enzyme with gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) and checked its catalytic function. AuNPs are synthesized using citrate reduction method and AgNPs were synthesized using biological route employing Ficus benghalensis and Ficus religiosa leaf extract as a reducing and stabilizing agent to reduce silver nitrate to silver atoms. A modulatory effect of nanoparticles on amylase activity was observed. Gold nanoparticles are excellent biocompatible surfaces for the immobilization of enzymes. Immobilized amylase showed 1- to 2-fold increase of activity compared to free enzyme. The biocatalytic activity of amylase in the bioconjugate was marginally enhanced relative to the free enzyme in solution. The bioconjugate material also showed significantly enhanced pH and temperature stability. The results indicate that the present study paves way for the modulator degradation of starch by the enzyme with AuNPs and biogenic AgNPs, which is a promising application in the medical and food industry. Kantrao Saware, Ravindra Mahadappa Aurade, P. D. Kamala Jayanthi, and Venkataraman Abbaraju Copyright © 2015 Kantrao Saware et al. All rights reserved. Structured Pd/γ-Al2O3 Prepared by Washcoated Deposition on a Ceramic Honeycomb for Compressed Natural Gas Applications Tue, 23 Jun 2015 09:49:40 +0000 The preparation of a coating procedure was studied, from the washcoating with γ-alumina to the deposition of palladium by excess solvent or incipient wetness impregnation. The powder and the washcoat layers were studied by different characterisation techniques such as SEM, BET surface area, and XRD. Vibration-resistance and heat-resistance were also evaluated. It was shown that the alumina layer is quite well deposited on the channel walls (SEM images). However, a detachment of the washcoat layer was observed after ultrasound treatment. It was proved that the monolith Pd impregnation method by incipient wetness impregnation is more efficient. The presence of palladium was confirmed using HRTEM, the palladium was present under the Pd (II) oxidation state, and the size of PdO particles varies between 2.5 and 3.1 nm. The catalytic properties of the monolith catalyst were carried out using temperature programmed surface reaction (TPSR). The efficiency of the procedure of the monolith catalyst preparation was confirmed by comparing the activity of the prepared catalyst with the one of a model catalyst. Małgorzata Adamowska and Patrick Da Costa Copyright © 2015 Małgorzata Adamowska and Patrick Da Costa. All rights reserved. Aqueous Synthesis of Ru Doped Hematite Nanostructures: A Morphological, Structural, Optical, and Magnetic Study Wed, 17 Jun 2015 11:07:09 +0000 Hematite nanorods doped with ruthenium were successfully deposited on fluorine doped tin oxide (FTO) glass substrates using aqueous chemical growth. Using complementary surface/interface investigation techniques, the Ru incorporation in the Ru-α-Fe2O3 nanorods was evidenced. The optical band gap was found to be Ru doping concentration dependent: varying from 2.32 (2) to 2.47 (2) eV. These band gap values are well suited for the targeted water splitting process without application of an external bias. Ceboliyozakha Leonard Ndlangamandla, Krish Bharuth-Ram, Osman Muzi Ndwandwe, Balla Diop Ngom, and Malik Maaza Copyright © 2015 Ceboliyozakha Leonard Ndlangamandla et al. All rights reserved. Issues Affecting the Synthetic Scalability of Ternary Metal Ferrite Nanoparticles Tue, 09 Jun 2015 11:16:44 +0000 Ternary Mn-Zn ferrite (MnxZn1-xFe2O4) nanoparticles (NPs) have been prepared by the thermal decomposition of an oleate complex, sodium dodecylbenzenesulfonate (SDBS) mediated hydrazine decomposition of the chloride salts, and triethylene glycol (TREG) mediated thermal decomposition of the metal acetylacetonates. Only the first method was found to facilitate the synthesis of uniform, isolable NPs with the correct Mn : Zn ratio (0.7 : 0.3) as characterized by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and inductively coupled plasma-optical emission spectroscopy (ICP-OES). Scaling allowed for retention of the composition and size; however, attempts to prepare Zn-rich ferrites did not result in NP formation. Thermogravimetric analysis (TGA) indicated that the incomplete decomposition of the metal-oleate complexes prior to NP nucleation for Zn-rich compositions is the cause. Lauren Morrow and Andrew R. Barron Copyright © 2015 Lauren Morrow and Andrew R. Barron. All rights reserved. Width of Nucleation Region of Si Nanocrystal Grains Prepared by Pulsed Laser Ablation with Different Laser Fluence Mon, 23 Mar 2015 11:21:36 +0000 Si nanocrystal grains were prepared by pulsed laser ablation with different laser fluence in Ar gas of 10 Pa at room temperature. The as-formed grains in the space deposited on the substrates and distributed in a certain range apart from target. According to the depositing position and radius of grains, the nucleation locations of grains in the space were roughly calculated. The results indicated that the width of nucleation region broadened with increasing of ion densities diagnosed by Langmuir probe, which increased with laser fluence from 2 J/cm2 to 6 J/cm2; that is, width of nucleation region broadened with addition of laser fluence. At the same time, the width broadened with the terminal formation position moving backward and the initial formation position of grains moving toward ablated spot. The experimental results were explained reasonably by nucleation thermokinetic theory. Zechao Deng, Xuexia Pang, Xuecheng Ding, Lizhi Chu, and Yinglong Wang Copyright © 2015 Zechao Deng et al. All rights reserved. Carbon Dot Based Sensing of Dopamine and Ascorbic Acid Mon, 29 Dec 2014 09:07:27 +0000 We demonstrate carbon dot based sensor of catecholamine, namely, dopamine and ascorbic acid. Carbon dots (CDs) were prepared from a green source: commercially available Assam tea. The carbon dots prepared from tea had particle sizes of ∼0.8 nm and are fluorescent. Fluorescence of the carbon dots was found to be quenched in the presence of dopamine and ascorbic acid with greater sensitivity for dopamine. The minimum detectable limits were determined to be 33 μM and 98 μM for dopamine and ascorbic acid, respectively. The quenching constants determined from Stern-Volmer plot were determined to be 5 × 10−4 and 1 × 10−4 for dopamine and ascorbic acid, respectively. A probable mechanism of quenching has been discussed in the paper. Upama Baruah, Neelam Gogoi, Achyut Konwar, Manash Jyoti Deka, Devasish Chowdhury, and Gitanjali Majumdar Copyright © 2014 Upama Baruah et al. All rights reserved. Synthesis of Platinum Nanoparticles from K2PtCl4 Solution Using Bacterial Cellulose Matrix Sun, 14 Dec 2014 07:15:31 +0000 Platinum (Pt) nanoparticles have been synthesized from a precursor solution of potassium tetrachloroplatinate (K2PtCl4) using a matrix of bacterial cellulose (BC). The formation of Pt nanoparticles occurs at the surface and the inside of the BC membrane by reducing the precursor solution with a hydrogen gas reductant. The Pt nanoparticles obtained from the variations of precursor concentration, between 3 mM and 30 mM, and the formation of Pt nanoparticles have been studied using X-ray diffraction (XRD), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), and thermogravimetry analysis (TGA). Based on X-ray diffraction patterns, Pt particles have sizes between 6.3 nm and 9.3 nm, and the Pt particle size increases with an increase in precursor concentration. The morphology of the Pt nanoparticles was observed by SEM-EDS and the content of Pt particles inside the membrane is higher than that on the surface of BC membranes. This analysis corresponds to the TGA analysis, but the TGA analysis is more representative in how it describes the content of Pt particles in the BC membrane. H. F. Aritonang, D. Onggo, C. Ciptati, and C. L. Radiman Copyright © 2014 H. F. Aritonang et al. All rights reserved. Aqueous Colloidal Stability of Graphene Oxide and Chemically Converted Graphene Thu, 13 Nov 2014 00:00:00 +0000 Graphene oxide (GO) was prepared by modified Hummer’s method, and chemically converted graphene (CCG) was prepared by further reduction of the aqueous GO colloid. The effect of pH on particle size, particle charge, and light absorption of the aqueous colloids of GO and CCG was studied with titration against HCl or NaOH, to find the ideal characteristics for a stable dispersion. The GO colloid was stable in the pH range of 4–11, whereas the CCG colloid gained stability at a relatively narrower pH range of 7–10. Poor stability of the colloids was observed for both GO and CCG colloids at both extremes of the pH scale. Both of the colloids exhibited average size of ~1 micron in the low pH range, whereas for higher pH the size ranged between 300 and 500 nm. The UV-Vis spectra showed absorption peak at 230 nm for GO colloids that shifted to 260 nm for the CCG colloid. Such shift can be ascribed to restoring of electronic conjugation of the C=C bonds in CCG. Swarnima Kashyap, Shashank Mishra, and Shantanu K. Behera Copyright © 2014 Swarnima Kashyap et al. All rights reserved. Spectropolarimetric Properties of a Gallium Nanoparticle Layer on a Sapphire Substrate Sun, 02 Nov 2014 13:47:49 +0000 Gallium nanoparticles (Ga NPs) are currently the subject of vigorous research as possible substrates in surface-enhanced Raman scattering (SERS) experiments in the ultraviolet spectral domain. Verification of any comprehensive model of the interaction of electromagnetic radiation with Ga NPs requires that complete polarimetric measurements be made. These spectropolarimetric properties can be obtained using a Mueller matrix spectropolarimeter (MMSP). The position of localized surface plasmon resonances (LSPRs) and spectral depolarization data of Ga NPs in the 300 to 1100 nm spectral region are presented. Spectral depolarization data may be of value in creating a better understanding of how light couples to individual nanoparticles, as well as the role played by interparticle coupling and the connection to phenomena such as SERS. Prashant Raman, Kirk Fuller, and Don A. Gregory Copyright © 2014 Prashant Raman et al. All rights reserved. Plasmonic and Thermooptical Properties of Spherical Metallic Nanoparticles for Their Thermoplasmonic and Photonic Applications Tue, 14 Oct 2014 00:00:00 +0000 Investigations and use of nanoparticles (NPs) as photothermal (PT) agents in laser and optical nanotechnology are fast growing areas of research and applications. The potential benefits of NPs applications include possibility for thermal imaging and treatment of materials containing of NPs, applications of NPs for light-to-thermal energy conversion, in catalysis, laser nanomedicine, and chemistry. Efficiency of applications of metallic NPs for laser and optical nanotechnology depends on plasmonic and thermophysical properties of NPs, characteristics of radiation, and surrounding medium. Here we present the results of comparative analysis of NP properties (plasmonic, thermooptical, and others) allowing selecting their parameters for thermoplasmonic and photonic applications. Plasmonic and thermooptical properties of several metallic (aurum, silver, platinum, cobalt, zinc, nickel, titanium, cuprum, aluminum, molybdenum, vanadium, and palladium) NPs are theoretically investigated and analysis of them is carried out. Investigation of the influence of NPs parameters (type of metal, radii, optical indexes, density, and heat capacity of NP material), characteristics of radiation (wavelength and pulse duration), and ambient parameters on plasmonic and thermophysical properties of NPs has been carried out. It was established that maximum value of thermooptical parameter (maximum NP temperature) can be achieved with the use of absorption efficiency factor of NP smaller than its maximum value. Victor K. Pustovalov, Liudmila G. Astafyeva, and Wolfgang Fritzsche Copyright © 2014 Victor K. Pustovalov et al. All rights reserved.