http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2013 , Hindawi Publishing Corporation . All rights reserved. Mon, 20 May 2013 15:02:07 +0000 http://www.hindawi.com/journals/jnt/2013/939531/ One-dimensional BiFeO3 (BFO) nanofibers fabricated by electrospinning of a solution of Nylon6/BFO followed by calcination were used for photocatalytic degradation of contaminants in water. The BFO fibers were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-Vis spectroscopy. The SEM images of the as-spun samples demonstrated the successful production of nanofibers and the SEM images of the samples after calcination confirmed the integrity of the continuous BFO nanofibers. XRD analysis indicated the dominant presence of BFO phase throughout the calcinated nanofibers. Photocatalytic activity of the nanofibers and their application in water purification were investigated against 4-chlorophenol (4CP) as a model water contaminant. The results of the UV-Vis spectroscopy show the degradation of the 4CP by means of the photocatalytic activity of the BFO nanofibers. The kinetics of the photodegradation of 4CP is believed to be governed by a pseudo-first-order kinetics model. Parmiss Mojir Shaibani, K. Prashanthi, Amirreza Sohrabi, and Thomas Thundat Copyright © 2013 Parmiss Mojir Shaibani et al. All rights reserved. Thu, 11 Apr 2013 16:55:18 +0000 http://www.hindawi.com/journals/jnt/2013/346581/ Nowadays, a very large proportion of new drug candidates emerging from drug discovery programmes are water insoluble and thus poorly bioavailable. To avoid this problem, nanotechnology for drug delivery has gained much interest as a way to improve the solubility problems. Nano refers to particles size range of 1–1000 nm. The reduction of drug particles into the submicron range leads to a significant increase in the dissolution rate and therefore enhances bioavailability. Nanosuspensions are part of nanotechnology. This interacts with the body at subcellular (i.e., molecular) scales with a high degree of specificity and can be potentially translated into targeted cellular and tissue-specific clinical applications designed to achieve maximal therapeutic efficacy with minimal side effects. Production of drugs as nanosuspensions can be developed for drug delivery systems as an oral formulation and nonoral administration. Here, this review describes the methods of pharmaceutical nanosuspension production including advantages and disadvantages, potential benefits, characterization tests, and pharmaceutical applications in drug delivery. Kumar Bishwajit Sutradhar, Sabera Khatun, and Irin Parven Luna Copyright © 2013 Kumar Bishwajit Sutradhar et al. All rights reserved. Thu, 28 Mar 2013 11:35:00 +0000 http://www.hindawi.com/journals/jnt/2013/978541/ Mallikarjuna N. Nadagouda, Dionysios (Dion) Demetriou Dionysiou, Darren A. Lytle, Thomas F. Speth, and Sharmila M. Mukhopadhyay Copyright © 2013 Mallikarjuna N. Nadagouda et al. All rights reserved. Thu, 07 Mar 2013 10:03:36 +0000 http://www.hindawi.com/journals/jnt/2013/140273/ Silver metal nanoparticles were immobilized in chitosan/carboxymethylcellulose/BMI.BF4(1-n-butyl-3-methylimidazolium tetrafluoroborate ionic liquid) (CS/CMC/IL) to form polymeric membrane with 20 μm thickness. The CS/CMC/IL polymeric membrane was prepared using a simple solution blending method. Irregularly shaped Ag(0) nanoparticles with monomodal size distributions of  nm Ag(0) were immobilized in the membrane. The presence of small Ag(0) nanoparticles induced an augmentation in the CS/CMC/IL film surface areas. The CS/CMC/IL membrane containing Ag(0) showed increase antimicrobial activity the Ag(0) concentration increased up to saturation at 10 mg. CS/CMC/IL membrane that contains Ag(0) nanoparticles has enhanced durability of the membrane and exhibited stronger antimicrobial activity against Escherichia coli and Staphylococcus aureus. Camila Quadros, Vinícius W. Faria, Manuela P. Klein, Plinho F. Hertz, and Carla W. Scheeren Copyright © 2013 Camila Quadros et al. All rights reserved. Tue, 15 Jan 2013 12:05:15 +0000 http://www.hindawi.com/journals/jnt/2013/736478/ We studied the photoluminescence (PL) of Si nanocrystals (Si-NCs) embedded in SiO2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm) inside the SiO2 achieving a robust and better protected system. After metal ion implantation (Ag or Au), and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs) could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H2/N2 and Ar) to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation. Jhovani Bornacelli, Jorge Alejandro Reyes Esqueda, Luis Rodríguez Fernández, and Alicia Oliver Copyright © 2013 Jhovani Bornacelli et al. All rights reserved. Thu, 10 Jan 2013 15:01:38 +0000 http://www.hindawi.com/journals/jnt/2013/768724/ We report a method of synthesis and optimization of amino-functionalized silica nanoparticles (SiNPs) and their in vitro evaluation as targeted delivery vehicles for the potential treatment of pancreatic cancer. SiNPs can efficiently encapsulate doxorubicin and can be attached to a targeting moiety such as anti-Claudin-4 (CLN4). The preferential uptake in pancreatic cancer cells, where CLN4 is overexpressed, of SiNPs when conjugated to CLN4 antibody (compared to nonconjugated SiNPs) was confirmed by confocal microscopy. SiNPs encapsulating doxorubicin had greater efficacy in MTT assays than free doxorubicin, and when conjugated to CLN4, the efficacy was dramatically increased (at 1 μM). No apparent carrier toxicity was observed when void SiNPs were used. SiNPs carrying a chemotherapeutic drug have the potential to be used as a targeted therapy for lethal cancers, such as pancreatic cancer. Also, incorporation of fluorescent probes in these SiNPs creates the possibility of their use as an imaging probe for diagnostic purposes. Abbey Y. Kardys, Dhruba J. Bharali, and Shaker A. Mousa Copyright © 2013 Abbey Y. Kardys et al. All rights reserved. Sun, 30 Dec 2012 13:34:10 +0000 http://www.hindawi.com/journals/jnt/2012/936041/ Materials in the nanometer size range may possess unique and beneficial properties, which are very useful for different medical applications including stomatology, pharmacy, and implantology tissue engineering. The application of nanotechnology to medicine, known as nanomedicine, concerns the use of precisely engineered materials at this length scale to develop novel therapeutic and diagnostic modalities. Nanomaterials have unique physicochemical properties, such as small size, large surface area to mass ratio, and high reactivity, which are different from bulk materials of the same composition. Polymeric and ceramic nanoparticles have been extensively studied as particulate carriers in the pharmaceutical and medical fields, because they show promise as drug delivery systems as a result of their controlled- and sustained-release properties, subcellular size, and biocompatibility with tissue and cells. These properties can be used to overcome some of the limitations found in traditional therapeutic and diagnostic agents. Nanotechnology is showing promising developments in many areas and may benefit our health and welfare. However, a wide range of ethical issues has been raised by this innovative science. Many authorities believe that these advancements could lead to irreversible disasters if not limited by ethical guidelines. Aura-Ileana Moreno-Vega, Teresa Gómez-Quintero, Rosa-Elvira Nuñez-Anita, Laura-Susana Acosta-Torres, and Víctor Castaño Copyright © 2012 Aura-Ileana Moreno-Vega et al. All rights reserved. Thu, 27 Dec 2012 15:16:10 +0000 http://www.hindawi.com/journals/jnt/2012/478381/ This paper demonstrates the effectiveness of a new type of hybrid nanocatalyst material that combines the high surface area of nanoparticles and nanotubes with the structural robustness and ease of handling larger supports. The hybrid material is made by fabricating palladium nanoparticles on two types of carbon supports: as-received microcellular foam (Foam) and foam with carbon nanotubes anchored on the pore walls (CNT/Foam). Catalytic reductive dechlorination of carbon tetrachloride with these materials has been investigated using gas chromatography. It is seen that while both palladium-functionalized carbon supports are highly effective in the degradation of carbon tetrachloride, the rate of degradation is significantly increased with palladium on CNT/Foam. However, there is scope to increase this rate further if the wettability of these structures can be enhanced in the future. Microstructural and spectroscopic analyses of the fresh and used catalysts have been compared which indicates that there is no change in density or surface chemical states of the catalyst after prolonged use in dechlorination test. This implies that these materials can be used repeatedly and hence provide a simple, powerful, and cost-effective approach for dechlorination of water. Hema Vijwani, Abinash Agrawal, and Sharmila M. Mukhopadhyay Copyright © 2012 Hema Vijwani et al. All rights reserved. Tue, 25 Dec 2012 15:14:54 +0000 http://www.hindawi.com/journals/jnt/2012/696310/ Vaishali R. Shinde, Won Bae Kim, Shrikrishna D. Sartale, and Tanaji P. Gujar Copyright © 2012 Vaishali R. Shinde et al. All rights reserved. Thu, 20 Dec 2012 08:15:42 +0000 http://www.hindawi.com/journals/jnt/2012/354809/ ZnO films constituted of porous sheet-like structures, formed by calcination of precursor, were examined using scanning electron microscopy and simultaneous small-angle scattering and diffraction of the synchrotron-sourced X-rays, under the grazing-incidence conditions. The presented analysis enabled insight into the complexity of the film morphology, which revealed substrate sensitivity on the microscopic and nanoscopic length scales. The average size and spatial arrangement of nanoparticles, single-crystal domains, and the average size and features of nanopores in sheet-like structures were determined for films deposited on glass, polycrystalline ZnO layer, and silicon. M. Lučić Lavčević, S. Bernstorff, P. Dubček, D. Jozić, I. Jerković, and Z. Marijanović Copyright © 2012 M. Lučić Lavčević et al. All rights reserved. Sun, 16 Dec 2012 15:42:27 +0000 http://www.hindawi.com/journals/jnt/2012/267135/ Guifu Zou, Hongmei Luo, Baoquan Sun, Menka Jain, and Huisheng Peng Copyright © 2012 Guifu Zou et al. All rights reserved. Tue, 30 Oct 2012 15:21:55 +0000 http://www.hindawi.com/journals/jnt/2012/708626/ In this work carbon aerogels were synthesized by catalytic chemical vapor deposition method (CCVD). Ferrocene were employed as a source both of catalytic material (Fe) and of carbon. Gaseous hydrogen and argon were used as reductant and carrier gas, respectively. The products of reaction were collected over alumina. The morphology and textural properties of the soot produced in the reaction chamber were investigated using Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, X-ray photoelectron spectroscopy, and N2 physisorption (BET and BHJ methods). After the evaluation of the porous structure of the synthesized products, 780 ± 20 m2/g of and 0.55 ± 0.02 cm3/g of were found. The presence of iron carbide and the partial oxidation of carbon nanostructures were revealed by XPS. Armando Peña, Julio Puerta, Aimé Guerrero, Edgar Cañizales, and Joaquín L. Brito Copyright © 2012 Armando Peña et al. All rights reserved. Tue, 09 Oct 2012 08:10:42 +0000 http://www.hindawi.com/journals/jnt/2012/690304/ Growth of single-walled carbon nanotubes (SWNTs) was carried out on SiO2/Si substrates with Pt catalysts at 400, 450, and 700°C under various ethanol pressures using an alcohol gas source method in a high vacuum, and the grown SWNTs were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. Irrespective of the growth temperature, both G band and RBM peaks were observed in the Raman spectra under the optimal ethanol pressure ( Pa), indicating that SWNTs grew below 450°C from Pt. At 400°C, both average diameter and diameter distribution were drastically reduced, and those were fairly smaller and narrower, compared to those for SWNTs grown with Co. Hiroki Kondo, Naoya Fukuoka, and Takahiro Maruyama Copyright © 2012 Hiroki Kondo et al. All rights reserved. Sat, 29 Sep 2012 12:40:06 +0000 http://www.hindawi.com/journals/jnt/2012/212486/ Silver nanoparticles (AgNano) as carrier of available oxygen (O2) and with high surface reactivity may increase O2 consumption, enhance fat uptake (FU), and stimulate growth and development. The objective was to investigate the effects of in ovo injection of AgNano on the metabolic rate (O2 consumption, CO2 production, and heat production, HP), fat uptake, and the development of broiler and layer hatchlings. AgNano concentrations (50, 75, and 100 mg/kg) were injected in ovo at day 1 of incubation to different breeds of broiler and layer chicken embryos. Oxygen consumption and subsequently FU did not increase linearly following AgNano treatment. FU was lower in hatchlings treated with 50 and 100 mg AgNano/kg, but surprisingly not in hatchlings treated with 75 mg AgNano/kg. Interestingly, the difference in FU between treatments was not reflected in hatchling development. The results indicated that AgNano affected metabolic rate and FU; however, it did not influence the development of hatchlings. This suggests that in ovo injection of AgNano reduces the need to use yolk fat as an energy source during embryonic development and consequently the remaining fat in the residual yolk sac may provide a potent source of nutritional reserves for chicks of few days after hatching. Lane Pineda, André Chwalibog, Ewa Sawosz, Anna Hotowy, Jan Elnif, and Filip Sawosz Copyright © 2012 Lane Pineda et al. All rights reserved. Tue, 25 Sep 2012 16:17:58 +0000 http://www.hindawi.com/journals/jnt/2012/619062/ Well controlled in length and highly aligned ZnO nanorods were grown on the gold-coated glass substrate by hydrothermal growth method. ZnO nanorods were functionalised with selective thallium (I) ion ionophore dibenzyldiaza-18-crown-6 (DBzDA18C6). The thallium ion sensor showed wide linear potentiometric response to thallium (I) ion concentrations ( M to  M) with high sensitivity of 36.87 ± 1.49 mV/decade. Moreover, thallium (I) ion demonstrated fast response time of less than 5 s, high selectivity, reproducibility, storage stability, and negligible response to common interferents. The proposed thallium (I) ion-sensor electrode was also used as an indicator electrode in the potentiometric titration, and it has shown good stoichiometric response for the determination of thallium (I) ion. Z. H. Ibupoto, Syed M. Usman Ali, K. Khun, and Magnus Willander Copyright © 2012 Z. H. Ibupoto et al. All rights reserved. Tue, 25 Sep 2012 15:05:10 +0000 http://www.hindawi.com/journals/jnt/2012/453953/ DNA self-assembly is a nanotechnology that folds DNA into desired shapes. Self-assembled DNA nanostructures, also known as origami, are increasingly valuable in nanomaterial and biosensing applications. Two ways to use DNA nanostructures in medicine are to form nanoarrays, and to work as vehicles in drug delivery. The DNA nanostructures perform well as a biomaterial in these areas because they have spatially addressable and size controllable properties. However, manually designing complementary DNA sequences for self-assembly is a technically demanding and time consuming task, which makes it advantageous for computers to do this job instead. We have developed a web server, FOLDNA, which can automatically design 2D self-assembled DNA nanostructures according to custom pictures and scaffold sequences provided by the users. It is the first web server to provide an entirely automatic design of self-assembled DNA nanostructure, and it takes merely a second to generate comprehensive information for molecular experiments including: scaffold DNA pathways, staple DNA directions, and staple DNA sequences. This program could save as much as several hours in the designing step for each DNA nanostructure. We randomly selected some shapes and corresponding outputs from our server and validated its performance in molecular experiments. Chensheng Zhou, Heng Luo, Xiaolu Feng, Xingwang Li, Jie Zhu, Lin He, and Can Li Copyright © 2012 Chensheng Zhou et al. All rights reserved. Mon, 17 Sep 2012 17:42:33 +0000 http://www.hindawi.com/journals/jnt/2012/237284/ This paper investigated toxicity of three engineered nanoparticles (ENP), namely, Al2O3, SiO2, and TiO2 to the unicellular green algae, exemplified by Pseudokirchneriella subcapitata with an emphasis on particle size. The changes in pH, cell counts, chlorophyll a, and lipid peroxidation were used to measure the responses of the algal species to ENP. The most toxic particle size was TiO2 at 42 nm with an EC20 of 5.2 mg/L and Al2O3 at 14–18 nm with an EC20 of 5.1 mg/L. SiO2 was the least toxic with an EC20 of 318 mg/L. Toxicity was positively related to the surface charge of both ENP and algae. The chlorophyll content of the algal cells was influenced by the presence of ENP, which resulted in limited light and availability of nutrients due to increase in turbidity and nutrient adsorption onto the ENP surface, separately. Lipid peroxidation was attributed to reactive oxygen species (ROS). Fast reaction between algal cells and ROS due to direct contact between TiO2 and algal cells is an important factor for lipid peroxidation. D. M. Metzler, A. Erdem, Y. H. Tseng, and C. P. Huang Copyright © 2012 D. M. Metzler et al. All rights reserved. Mon, 17 Sep 2012 13:17:19 +0000 http://www.hindawi.com/journals/jnt/2012/480813/ Nanowires with magnetic doping centers are an exciting candidate for the study of spin physics and proof-of-principle spintronics devices. The required heavy doping can be expected to have a significant impact on the nanowires' electron transport properties. Here, we use thermopower and conductance measurements for transport characterization of Ga0.95Mn0.05As nanowires over a broad temperature range. We determine the carrier type (holes) and concentration and find a sharp increase of the thermopower below temperatures of 120 K that can be qualitatively described by a hopping conduction model. However, the unusually large thermopower suggests that additional mechanisms must be considered as well. Phillip M. Wu, Waldomiro Paschoal Jr., Sandeep Kumar, Christian Borschel, Carsten Ronning, Carlo M. Canali, Lars Samuelson, Håkan Pettersson, and Heiner Linke Copyright © 2012 Phillip M. Wu et al. All rights reserved. Wed, 12 Sep 2012 13:13:10 +0000 http://www.hindawi.com/journals/jnt/2012/429021/ Poly(vinyl pyrrolidone)(PVP)/(strontium/barium acetate)/titanium isopropoxide composite fibers were prepared by electrospinning technique via sol-gel process. Diameters of fibers prepared by calcinations of PVP composite fibers were 80–140 nm (solid) and 1.2-2.2 μm (hollow fibers prepared by core-shell method). These fibers were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM) analytical techniques. XRD results showed better crystalline nature of the materials when calcined at higher temperatures. SEM and TEM results clearly showed the formation of hollow submicrometer tubes. The surface area of the samples determined by BET analysis indicated that hollow fibers have ~20% higher surface area than solid fibers. The UV studies indicate better detoxification properties of the hollow fibers compared to solid fibers. Satya R. Agarwal, Subramanian Sundarrajan, Arunachalam Venkatesan, and Seeram Ramakrishna Copyright © 2012 Satya R. Agarwal et al. All rights reserved. Mon, 10 Sep 2012 09:54:06 +0000 http://www.hindawi.com/journals/jnt/2012/875815/ The preparation of polytetrafluoroethylene-poly(methyl methacrylate) (PTFE-PMMA) core-shell particles was described, featuring controlled size and narrow size distribution over a wide compositional range, through a seeded emulsion polymerization starting from a PTFE seed of 26 nanometers. Over the entire MMA/PTFE range, the particle size increases as the MMA/PTFE ratio increases. A very precise control over the particle size can be exerted by properly adjusting the ratio between the monomer and the PTFE seed. Particles in the 80–240 nm range can be prepared with uniformity indexes suited to build 2D and 3D colloidal crystals. These core-shell particles were employed to prepare nanocomposites with different compositions, through an annealing procedure at a temperature higher than the glass transition temperature of the shell forming polymer. A perfect dispersion of the PTFE particles within the PMMA matrix was obtained and optically transparent nanocomposites were prepared containing a very high PTFE amount. Diego Antonioli, Michele Laus, Giampaolo Zuccheri, Valerj Kapeliouchko, Maria Cristina Righetti, Luca Boarino, and Katia Sparnacci Copyright © 2012 Diego Antonioli et al. All rights reserved. Wed, 05 Sep 2012 15:02:34 +0000 http://www.hindawi.com/journals/jnt/2012/324380/ Aerosol-based direct-write refers to the additive process of printing CAD/CAM features from an apparatus which creates a liquid or solid aerosol beam. Direct-write technologies are poised to become useful tools in the microelectronics industry for rapid prototyping of components such as interconnects, sensors, and thin film transistors (TFTs), with new applications for aerosol direct-write being rapidly conceived. This paper aims to review direct-write technologies, with an emphasis on aerosol-based systems. The different currently available state-of-the-art systems such as Aerosol Jet CAB-DW, MCS, and aerodynamic lenses are described. A review and analysis of the physics behind the fluid-particle interactions including Stokes and Saffman force, experimental observations, and how a full understanding of theory and experiments can lead to new technology are presented. Finally, the applications of aerosol direct-write for microelectronics are discussed. Justin M. Hoey, Artur Lutfurakhmanov, Douglas L. Schulz, and Iskander S. Akhatov Copyright © 2012 Justin M. Hoey et al. All rights reserved. Wed, 05 Sep 2012 14:47:51 +0000 http://www.hindawi.com/journals/jnt/2012/195761/ Nanoparticle suspensions represent a promising route toward low cost, large area solution deposition of functional thin films for applications in energy conversion, flexible electronics, and sensors. However, parameters such size, stoichiometry, and electronic properties must be controlled to achieve best results for the target application. In this report, we demonstrate that such control can be achieved via in situ chemical oxidation of MoO𝑥 nanoparticles in suspensions. Starting from a microwave-synthesized suspension of ultrasmall (𝑑∼2 nm) MoO𝑥 nanoparticles in n-butanol, we added H2O2 at room temperature to chemically oxidize the nanoparticles. We systematically varied H2O2 concentration and reaction time and found that they significantly affected oxidation state and work function of MoO𝑥 nanoparticle films. In particular, we achieved a continuous tuning of MoO𝑥 work function from 4.4 to 5.0 eV, corresponding to oxidation of as-synthesized MoO𝑥 nanoparticle (20% Mo6+) to essentially pure MoO3. This was achieved without significantly modifying nanoparticle size or stability. Such precise control of MoO𝑥 stoichiometry and work function is critical for the optimization of MoO𝑥 nanoparticles for applications in organic optoelectronics. Moreover, the simplicity of the chemical oxidation procedure should be applicable for the development of other transition oxide nanomaterials with tunable composition and properties. Yun-Ju Lee, Diego Barrera, Kaiyuan Luo, and Julia W. P. Hsu Copyright © 2012 Yun-Ju Lee et al. All rights reserved. Wed, 05 Sep 2012 07:35:14 +0000 http://www.hindawi.com/journals/jnt/2012/610408/ Junfeng Geng, Kun'ichi Miyazawa, Zheng Hu, Ilia A. Solov'yov, and Angel Berenguer-Murcia Copyright © 2012 Junfeng Geng et al. All rights reserved. Thu, 30 Aug 2012 14:21:53 +0000 http://www.hindawi.com/journals/jnt/2012/910761/ The experimental data of studies of layered organic-inorganic nanocomposites ((𝛽)-Zn(OH)2+DS) and (Cu2(OH)3+DS) which were produced in the result ablation of zinc and copper in aqueous solutions of surfactants—dodecyl sodium sulfate (SDS) and sodium bis-ethylhexyl succinate (AOT)—are presented. Dependence of the formation dynamics of these composites on an exposure time of radiation and on an aging time of colloids was studied by the absorption spectroscopy, by X-ray diffraction, by scanning electron (SEM), and atomic force microscopy (AFM). Composite (Cu2(OH)3+DS) with bilayered structure was produced by method of laser ablation of the copper metal target in liquid for the first time. V. T. Karpukhin, M. M. Malikov, T. I. Borodina, G. E. Val'yano, and O. A. Gololobova Copyright © 2012 V. T. Karpukhin et al. All rights reserved. Tue, 28 Aug 2012 12:08:54 +0000 http://www.hindawi.com/journals/jnt/2012/323145/ We report the investigation of temperature-dependent magnetic properties and photocatalytic activity of CoFe2O4-Fe3O4 magnetic nanocomposites (MNCs) synthesized by hydrothermal process. Room-temperature magnetic hysteresis (M-H) loops result enhanced saturation magnetization of 90 emu/g and coercivity (𝐻𝐶) of 530 Oe for CoFe2O4-Fe3O4 MNCs. With decreasing temperature to 20 K, 𝐻𝐶 increases from 500 Oe to 6800 Oe, and the M-H loops exhibit exchange coupling feature between CoFe2O4 and Fe3O4. Low- and high-temperature-dependent magnetization measurements confirm that the blocking temperature lies above 300 K and the presence of two magnetic phase transitions corresponding to CoFe2O4 and Fe3O4, respectively. The photocatalytic activity of the MNCs has been examined on the reduction of methyl orange (MO), a colored compound used in dyeing and printing textiles. The observed results suggest that the CoFe2O4-Fe3O4 MNCs act as an excellent photocatalyst on the degradation of organic contaminants and degrade 93% of MO in 5 hours of UV irradiation. The photocatalytic activity of MNCs is attributed to remarkably high band gap energy and small particle size. Also, the MNCs with a reproducible photocatalytic activity are well separable from water media by applying external magnetic field and acts as a promising catalyst for the remediation of textile wastewater. Debabrata Mishra, Kula Kamal Senapati, Chandan Borgohain, and A. Perumal Copyright © 2012 Debabrata Mishra et al. All rights reserved. Tue, 28 Aug 2012 11:12:09 +0000 http://www.hindawi.com/journals/jnt/2012/728326/ Magnetite (Fe3O4) nanoparticles prepared by microwave-assisted hydrothermal synthesis have been characterized in terms of morphological and structural features. Electron micrographs collected in both scanning (SEM) and transmission (TEM) modes and evaluations of X-ray powder diffraction (XRD) patterns have indicated the achievement of a monodispersed crystallite structure with particles having an average size around 15–20 nm. Structural investigations by Micro-Raman spectroscopy highlighted the obtainment of magnetite nanocrystals with a partial surface oxidation to maghemite (γ-Fe3O4). Preliminary attention has been also paid to the use of these magnetite nanoparticles as filler for a commercial polymethylmethacrylate resin. Hybrid formulations containing up to 3 wt% of nanoparticles were prepared by melt blending and characterized by calorimetric and thermogravimetric tests. For sake of comparison, same formulations containing commercial Fe3O4 nanoparticles are also reported. Calorimetric characterization indicates an increase of both glass transition temperature and thermal stability of the nanocomposite systems when loaded with the synthesized magnetite nanoparticles rather then loaded with the same amount of commercial Fe3O4. This first observation represents just one aspect of the promising potentiality offered by the novel magnetic nanoparticles when mixed with PMMA. Pietro Russo, Domenico Acierno, Mariano Palomba, Gianfranco Carotenuto, Roberto Rosa, Antonino Rizzuti, and Cristina Leonelli Copyright © 2012 Pietro Russo et al. All rights reserved. Thu, 23 Aug 2012 10:52:09 +0000 http://www.hindawi.com/journals/jnt/2012/103439/ Step-and-repeat UV nanoimprinting for large-scale nanostructure fabrication under atmospheric pressure was realized using high-viscosity photocurable resin and a simple nanoimprinting system. In step-and-repeat UV nanoimprinting under atmospheric pressure using low-viscosity resin, large-scale nanostructure fabrication is very difficult, due to bubble defects and nonuniformity of the residual layer. To minimize bubble defects and nonuniformity of the residual layer, we focused on the damping effects of photocurable resin viscosity. Fabrication of 165 dies was successfully demonstrated in a 130×130 mm2 area on an 8 in silicon substrate by step-and-repeat UV nanoimprinting under atmospheric pressure using high-viscosity photocurable resin. Nanostructures with widths and spacing patterns from 80 nm to 3 μm and 200 nm depth were formed using a quartz mold. Bubble defects were not observed, and residual layer uniformity was within 30 nm ±10%. This study reports on simple step-and-repeat UV nanoimprinting under atmospheric pressure using high-viscosity photocurable resin, as a very widely available method for large-scale mass production of nanostructures. Kentaro Ishibashi, Hiroshi Goto, Jun Mizuno, and Shuichi Shoji Copyright © 2012 Kentaro Ishibashi et al. All rights reserved. Wed, 22 Aug 2012 13:50:25 +0000 http://www.hindawi.com/journals/jnt/2012/216050/ Anionic tris (biimidazolate) nickelate (II) ([Ni(Hbim)3]−), which is a hydrogen-bonding (H-bonding) molecular building block, undergoes self-organization into honeycomb-sheet superstructures connected by complementary intermolecular H-bonds. The crystal obtained from the stacking of these sheets is assembled into channel frameworks, approximately 2 nm wide, that clathrate two cationic K+-crown ether derivatives organised into one-dimensional (1D) double-columnar arrays. In this study, we have shown that all five cationic guest-included crystals form nanochannel structures that clathrate the 1-D double-columnar arrays of one of the four types of K+-crown ether derivatives, one of which induces a polymorph. This is accomplished by adaptably fitting two types of anionic [Ni(Hbim)3]− host arrays. One is a ΔΛ−ΔΛ−ΔΛ⋯ network with H-bonded linkages alternating between the two different optical isomers of the Δ and Λ types with flexible H-bonded [Ni(Hbim)3]−. The other is a ΔΔΔ−ΛΛΛ⋯ network of a racemate with 1-D H-bonded arrays of the same optical isomer for each type. Thus, [Ni(Hbim)3]− can assemble large cations such as K+ crown-ether derivatives into double-columnar arrays by highly recognizing flexible H-bonding arrangements with two host networks of ΔΛ−ΔΛ−ΔΛ⋯ and ΔΔΔ−ΛΛΛ⋯. Makoto Tadokoro, Kyosuke Isoda, Yasuko Tanaka, Yuko Kaneko, Syoko Yamamoto, Tomoaki Sugaya, and Kazuhiro Nakasuji Copyright © 2012 Makoto Tadokoro et al. All rights reserved. Wed, 22 Aug 2012 11:05:12 +0000 http://www.hindawi.com/journals/jnt/2012/387586/ We report a novel light management approach based on solution-processed nanowire (NW) coating for enhancing organic solar cell efficiency. A titanium dioxide (TiO2) NW dispersion was produced by electrospinning. The coatings with various coverage fractions were fabricated by a simple solution casting of a TiO2 NW dispersion. Reduced reflectivity was observed for the NW-coated glass slide. The bulk-heterojunction organic solar cells with the NW coating showed improved power conversion efficiencies (PCEs) due to their antireflection and light trapping effects in the active layer. In addition, the PCE of the cell with the NW coating was improved compared with that without the NW coating for incident angles above 70° (increased by a maximum of 51.6% at an incident angle of 85°). These results indicate that solution-processed NW coating is a promising light management approach easily scalable and applicable to a wide range of devices, including solar cells. K. Tsuboi, T. Fukawa, Y. Konosu, H. Matsumoto, and A. Tanioka Copyright © 2012 K. Tsuboi et al. All rights reserved. Wed, 15 Aug 2012 14:17:42 +0000 http://www.hindawi.com/journals/jnt/2012/819281/ A functional carbon-nanotube (CNT)-composite paper is described in which the CNTs are aligned. This “aligned-CNT composite paper” is a flexible composite material that has CNT functionality (e.g., electrical conductivity) despite being a paper. An advanced fabrication method was developed to overcome the problem of previous CNT-composite papers, that is, reduced conductivity due to random CNT alignment. Aligning the CNTs by using an alternating current (AC) field was hypothesized to increase the electrical conductivity and give the paper an anisotropic characteristic. Experimental results showed that a nonionic surfactant was not suitable as a CNT dispersant for fabricating aligned-CNT composite paper and that catechin with its six-membered rings and hydrophilic groups was suitable. Observation by scanning electron microscopy of samples prepared using catechin showed that the CNTs were aligned in the direction of the AC field on the paper fibers. Measurement of the electric conductivity showed that the surface resistance was different between the direction of the aligned CNTs (high conductivity) and that of verticality (low). The conductivity of the aligned-CNT-composite paper samples was higher than that of nonaligned samples. This unique and functional paper, which has high and anisotropic conductivity, is applicable to a conductive material to control the direction of current. Yuki Fujitsuka and Takahide Oya Copyright © 2012 Yuki Fujitsuka and Takahide Oya. All rights reserved.