Journal of Nanomaterials The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. Fast and Straightforward Synthesis of Luminescent Titanium(IV) Dioxide Quantum Dots Thu, 20 Jul 2017 07:21:59 +0000 The nucleus of titania was prepared by reaction of solution titanium oxosulphate with hydrazine hydrate. These titania nuclei were used for titania quantum dots synthesis by a simple and fast method. The prepared titanium(IV) dioxide quantum dots were characterized by measurement of X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), high-resolution electron microscopy (HRTEM), and selected area electron diffraction (SAED). The optical properties were determined by photoluminescence (PL) spectra. The prepared titanium(IV) dioxide quantum dots have the narrow range of UV excitation (365–400 nm) and also a close range of emission maxima (450–500 nm). Václav Štengl, Jiří Henych, Martin Šťastný, and Martin Kormunda Copyright © 2017 Václav Štengl et al. All rights reserved. The Influence of Spherical Nano-SiO2 Content on the Thermal Protection Performance of Thermal Insulation Ablation Resistant Coated Fabrics Thu, 20 Jul 2017 00:00:00 +0000 In the high temperatures experienced in fire, radiant heat accounts for 80% of the total heat flow; therefore, improving the radiation protection is the best way to enhance the thermal protective performance of thermal insulation ablation resistant coated fabrics. To achieve this goal, the coating process and the ingredients used were optimized, spherical nano-SiO2 and other particles were added, and thermal insulation ablation resistant coated fabrics with high radiant heat reflectivity were prepared. The influence of the spherical nano-SiO2 content on the thermal protection performance of the prepared coated fabrics was investigated. Research showed that (1) the radiant heat reflectivity of the prepared coated fabrics improves significantly with increasing content of spherical nano-SiO2; when the mass fraction of spherical nano-SiO2 is 15%, the reflectivity of coated fabrics is at its largest, and its average value was 74.30%. At present, the average size of grains in samples increased 1.9 times; (2) after adding the spherical nano-SiO2, the thermal stability of the thermal insulation ablation resistant coated fabrics is significantly improved; the residual mass is as high as 88.49% at 1200°C, which is 18.77% higher than the residual mass of the coated fabrics with no spherical nano-SiO2 added at the same temperature. Guoyi Liu, Yuanjun Liu, and Xiaoming Zhao Copyright © 2017 Guoyi Liu et al. All rights reserved. Writing Field Analysis for Shingled Bit-Patterned Magnetic Recording Thu, 20 Jul 2017 00:00:00 +0000 A novel method utilizing response surface methodology (RSM) is proposed for effective analysis of the combined influence of writing head geometry and media properties on writing field performance. The method comprises two main modules: () a parametric writing head model based on finite element electromagnetic field analysis and () an effective writing field gradient model based on RSM. Using the method proposed, the writing performance of an asymmetrically shielded writing head for shingled magnetic recording on bit-patterned media (SMR-BPM) is analyzed. The results show that the shielding trailing gap and medium coercivity primarily impact the effective writing field (EWF) gradient and that the shielding side gap has a secondary impact. More importantly, the analysis shows a strong interaction effect between the influences of writing head geometry and medium coercivity on the EWF gradient, which indicates the need for inclusive design. X. G. Li, Z. J. Liu, A. G. Kang, and X. Y. Xie Copyright © 2017 X. G. Li et al. All rights reserved. Evaluation of Mechanical Properties of Σ5(210)/[001] Tilt Grain Boundary with Self-Interstitial Atoms by Molecular Dynamics Simulation Thu, 20 Jul 2017 00:00:00 +0000 Grain boundary (GB) can serve as an efficient sink for radiation-induced defects, and therefore nanocrystalline materials containing a large fraction of grain boundaries have been shown to have improved radiation resistance compared with their polycrystalline counterparts. However, the mechanical properties of grain boundaries containing radiation-induced defects such as interstitials and vacancies are not well understood. In this study, we carried out molecular dynamics simulations with embedded-atom method (EAM) potential to investigate the interaction of Σ5(210)/[] symmetric tilt GB in Cu with various amounts of self-interstitial atoms. The mechanical properties of the grain boundary were evaluated using a bicrystal model by applying shear deformation and uniaxial tension. Simulation results showed that GB migration and GB sliding were observed under shear deformation depending on the number of interstitial atoms that segregated on the boundary plane. Under uniaxial tension, the grain boundary became a weak place after absorbing self-interstitial atoms where dislocations and cracks were prone to nucleate. Liang Zhang, Cheng Lu, Linqing Pei, Xing Zhao, Jie Zhang, and Kiet Tieu Copyright © 2017 Liang Zhang et al. All rights reserved. Nanoparticles Decorated on Resin Particles and Their Flame Retardancy Behavior for Polymer Composites Wed, 19 Jul 2017 06:13:02 +0000 New nanocomposites have been developed by doping of amberlite IR120 resin with spherical TiO2 nanoparticles in the presence of maleate diphosphate. Polystyrene composites of resin, maleate diphosphate, and resin-maleate diphosphate were prepared individually. This is in addition to preparation of polymer nanocomposites of polystyrene-resin doped TiO2 nanoparticles-maleate diphosphate. The flame retardancy and thermal stability properties of these developed polymer composites were evaluated. The inclusion of resin and resin doped nanoparticles improved the fire retardant behavior of polystyrene composites and enhanced their thermal stability. Synergistic behavior between flame retardant, resin, and nanoparticles was detected. The rate of burning of the polymer nanocomposites was recorded as 10.7 mm/min achieving 77% reduction compared to pure polystyrene (46.5 mm/min). The peak heat release rate (PHRR) of the new polymer composites has reduced achieving 46% reduction compared to blank polymer. The morphology and dispersion of nanoparticles on resin and in polymer nanocomposites were characterized using transmission and scanning electron microscopy, respectively. The flame retardancy and thermal properties were evaluated using UL94 flame chamber, cone tests, and thermogravimetric analysis, respectively. Nour F. Attia and Mohamed Zayed Copyright © 2017 Nour F. Attia and Mohamed Zayed. All rights reserved. Plasma Treated Active Carbon for Capacitive Deionization of Saline Water Wed, 19 Jul 2017 00:00:00 +0000 The plasma treatment on commercial active carbon (AC) was carried out in a capacitively coupled plasma system using Ar + 10% O2 at pressure of 4.0 Torr. The RF plasma power ranged from 50 W to 100 W and the processing time was 10 min. The carbon film electrode was fabricated by electrophoretic deposition. Micro-Raman spectroscopy revealed the highly increased disorder of sp2 C lattice for the AC treated at 75 W. An electrosorption capacity of 6.15 mg/g was recorded for the carbon treated at 75 W in a 0.1 mM NaCl solution when 1.5 V was applied for 5 hours, while the capacity of the untreated AC was 1.01 mg/g. The plasma treatment led to 5.09 times increase in the absorption capacity. The jump of electrosorption capacity by plasma treatment was consistent with the Raman spectra and electrochemical double layer capacitance. This work demonstrated that plasma treatment was a potentially efficient approach to activating biochar to serve as electrode material for capacitive deionization (CDI). Aiping Zeng, Maheshwar Shrestha, Keliang Wang, Victor F. Neto, Bárbara Gabriel, and Qi Hua Fan Copyright © 2017 Aiping Zeng et al. All rights reserved. Correlation between Structures and Antioxidant Activities of Polyvinylpyrrolidone/Garcinia mangostana L. Extract Composite Nanofiber Mats Prepared Using Electrospinning Tue, 18 Jul 2017 08:19:18 +0000 Nanofiber mats of polyvinyl(pyrrolidone) (PVP) with Garcinia mangostana extract (GME) as the encapsulated drug have been developed using electrospinning. SEM images of all electrospun PVP/GME composite nanofiber mats showed that they had similar and smooth morphology, no beads, and spindle shape. Its average diameter decreased and its surface area therefore increased with the decrease of its PVP concentration. The benefit of high surface area is obvious in drug delivery systems for poorly water-soluble drugs. Their FTIR spectra indicated that PVP and GME interacted intermolecularly via hydrogen bonds in the composite nanofiber mats. A conformational change in the C-H chain of PVP occurred in the composite nanofiber mats due to the intermolecular interactions. Their XRD patterns confirmed that they were amorphous because of amorphization during electrospinning. The XRD analyses also strengthened the FTIR studies; namely, GME and PVP formed intermolecular interactions in the electrospun composite nanofiber mats. As a result, GME as the encapsulated drug was molecularly dispersed in the electrospun PVP nanofiber matrix that functioned as a drug delivery system. From the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the composite nanofiber mats exhibited very high antioxidant activities despite having been exposed to high voltage during electrospinning. Therefore, they are potential antioxidant products for food and pharmaceutics. Ida Sriyanti, Dhewa Edikresnha, Annisa Rahma, Muhammad Miftahul Munir, Heni Rachmawati, and Khairurrijal Khairurrijal Copyright © 2017 Ida Sriyanti et al. All rights reserved. Lignocellulosic Micro- and Nanomaterials as Copper Frames for the Evaluation of the Copper(I)-Catalyzed Azide-Alkyne Cycloaddition Tue, 18 Jul 2017 07:04:09 +0000 Copper was immobilized onto carboxymethyl cellulose, nanofibrillated cellulose, TEMPO-nanofibrillated cellulose, and lignin. The lignocellulosic frames were used with the aim of providing an effective support for catalyst copper and allowing its further reutilization. Each organic support was successful and effective in the coupling of copper with the exception of lignin. These complexes were used as heterogeneous catalysts to produce 1-benzyl-4-phenyl-1H-1,2,3-triazole from the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) between benzyl azide and phenylacetylene. Each reaction was carried out in water and acetonitrile. Those performed in water were completed in 15 minutes while those done in acetonitrile were allowed to react overnight, reaching completion in less than 20 hours. The yields for Cu-CMC resulted in over 90% for those reactions performed in acetonitrile. All catalysts were easy to recover except Cu-lignin which could not be filtered or extracted from the reaction effluent. Charles W. Owens, Gloria S. Oporto, Björn C. G. Söderberg, and Katherine E. Lambson Copyright © 2017 Charles W. Owens et al. All rights reserved. Growth of Ultralong Ag Nanowires by Electroless Deposition in Hot Ethylene Glycol for Flexible Transparent Conducting Electrodes Tue, 18 Jul 2017 00:00:00 +0000 High aspect ratio silver (Ag) nanowires with an average length of 25.4 μm and diameter of 102.8 nm were successfully prepared by electroless deposition in hot ethylene glycol (160°C) for 1 h in the presence of PVP. It was found that both PVP concentration and molecular weight significantly influence the morphology and yield of Ag nanowires in solution. Using PVP MW = 55,000, addition of lower amounts of PVP led to formation of large irregularly shaped Ag particles together with a few rod-like structures. Increasing PVP concentration generally resulted in longer and thinner Ag nanowires. On the other hand, low molecular weight PVP produced spherical Ag particles even at high PVP concentration. Ag nanowire flexible transparent conducting electrodes attained a sheet resistance of about 92.5 Ω/sq at an optical transmittance of about 79.6% without any heat treatment. In addition, no significant change in optical and electrical properties was observed after several cycles of bending and adhesion test. Nathaniel de Guzman and Mary Donnabelle L. Balela Copyright © 2017 Nathaniel de Guzman and Mary Donnabelle L. Balela. All rights reserved. Recent Progress in the Fabrication of Low Dimensional Nanostructures via Surface-Assisted Transforming and Coupling Mon, 17 Jul 2017 09:56:14 +0000 Polymerization of functional organics into covalently cross-linked nanostructures via bottom-up approach on solid surfaces has attracted tremendous interest recently, due to its appealing potentials in fabricating novel and artificial low dimensional nanomaterials. While there are various synthetic approaches being proposed and explored, this paper reviews the recent progress of on-surface coupling strategies towards the synthesis of low dimensional nanostructures ranging from 1D nanowire to 2D network and describes their advantages and drawbacks during on-surface process and phase transformations, for example, from molecular self-assembly to on-surface polymerization. Specifically, Ullmann reaction is discussed in detail and the mechanism governing nanostructures’ transforming effect by surface treatment is exploited. In the end, it is summarized that the hierarchical polymerization combined with Ullmann coupling makes it possible to realize the selection of different synthetic pathways and phase transformations and obtain novel organometallic nanowire with metalorganic bonding. Jinbang Hu, Zhaofeng Liang, Kongchao Shen, Haoliang Sun, Zheng Jiang, and Fei Song Copyright © 2017 Jinbang Hu et al. All rights reserved. Influence of MWCNTs on β-Phase PVDF and Triboelectric Properties Sun, 16 Jul 2017 07:17:28 +0000 The surface of multiwalled carbon nanotubes (MWCNTs) was chemically modified using 1-pyrenebutyric acid (PBA) to improve its compatibility with polyvinylidene fluoride (PVDF). The carboxylic acid groups of the MWCNTs-PBA (PCNTs) provide a β-phase nucleation site to the fluorine of PVDF along their surface. The content of the β-phase crystalline structure of PVDF was found to be the highest at a concentration of 1.0 wt.% of PCNTs, and these PVDF-PCNTs composites were utilized as active layers in triboelectric devices. The maximum output voltage achieved was 16 volts at a concentration of 1.0 wt.% of PCNTs in the PVDF composites. Sejung Kim, Youngjun Song, and Michael J. Heller Copyright © 2017 Sejung Kim et al. All rights reserved. Structural and Chemical Characterization of Silica Spheres before and after Modification by Silanization for Trypsin Immobilization Thu, 13 Jul 2017 00:00:00 +0000 In the last decades, silica particles of a variety of sizes and shapes have been characterized and chemically modified for several applications, from chromatographic separation to dental supplies. The present study proposes the use of aminopropyl triethoxysilane (APTS) silanized silica particles to immobilize the proteolytic enzyme trypsin for the development of a bioreactor. The major advantage of the process is that it enables the polypeptides hydrolysis interruption simply by removing the silica particles from the reaction bottle. Silanized silica surfaces showed significant morphological changes at micro- and nanoscale level. Chemical characterization showed changes in elemental composition, chemical environment, and thermal degradation. Their application as supports for trypsin immobilization showed high immobilization efficiency at reduced immobilization times, combined with more acidic conditions. Indirect immobilization quantification by reversed-phase ultrafast high performance liquid chromatography proved to be a suitable approach due to its high linearity and sensitivity. Immobilized trypsin activities on nonmodified and silanized silica showed promising features (e.g., selective hydrolysis) for applications in proteins/peptides primary structure elucidation for proteomics. Silanized silica system produced some preferential targeting peptides, probably due to the hydrophobicity of the nanoenvironment conditioned by silanization. Eduardo F. Barbosa and Luciano P. Silva Copyright © 2017 Eduardo F. Barbosa and Luciano P. Silva. All rights reserved. Study on the Effect of γ-Irradiation on Gadolinium Oxysulfide Nanophosphors (Gd2O2S-NPs) Wed, 12 Jul 2017 00:00:00 +0000 Gadolinium oxysulfide nanophosphors (Gd2O2S-NPs) have been successfully synthesized using γ-irradiation and hydrogenation treatment. The primary stage of Gd2O2S-NPs synthesis was carried out using various doses of γ-irradiation to form diverse sizes of Gd2(SO4)3 precursor, followed by hydrogenation treatment at 900°C for 2 hours to form Gd2O2S-NPs. Then, the nanophosphors were characterized for the structure, morphology, and luminescence properties through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and photoluminescence spectrometer (PL). Pure hexagonal phase of Gd2O2S-NPs was obtained with high crystallinity and without any impurities. The morphologies were observed from grain-like nanostructures transformed to spherical shape as the irradiation dose reached 40 kGy. Besides, Gd2O2S-NPs which were prepared at highest irradiation dose of 40 kGy show highest intensity of emission peak at 548 nm and corresponded to Stark level transition from the state of Gd3+ ion. It can be emphasized that the different doses of γ-irradiation influenced the nucleation event of Gd2(SO4)3 precursor thus affecting the morphology and size particles of Gd2O2S-NPs. Hence, from the results, it can be suggested that Gd2O2S-NPs can be a promising host for optical applications. Muhammad Hassyakirin Hasim, Irman Abdul Rahman, Sapizah Rahim, Muhammad Taqiyuddin Mawardi Ayob, Shamellia Sharin, and Shahidan Radiman Copyright © 2017 Muhammad Hassyakirin Hasim et al. All rights reserved. The Influence of Parameters of Ink-Jet Printing on Photoluminescence Properties of Nanophotonic Labels Based on Ag Nanoparticles for Smart Packaging Tue, 11 Jul 2017 00:00:00 +0000 Ag nanoparticles are perspective for the use in ink-jet printed smart packaging labels in order to protect a customer from counterfeit or inform them about the safety of consumption of a packaged product via changeable luminescence properties. It is determined that, to obtain printed images with the highest luminescence intensity, using the most technologically permissible concentration of fluorescent component in the ink composition and applying inks to papers with the lowest absorbance are recommended. The highest contrast of a tone fluorescent image can be obtained on papers with high degree of sizing. It is found that the use of papers with low optical brightness agent (OBA) content with a wide range of luminescence intensity allows obtaining the same visual legibility of a printed nanophotonic label. The increase in the relative area of raster elements of an image leads to nonlinear increase in luminescence intensity of printed images in long-wave area of visible spectrum, affecting the luminescence color of a printed label. For wide industrial production of printed nanophotonic labels for smart packaging, the created principles of reproduction of nanophotonic images applied onto paper materials by ink-jet printing technique using printing inks containing Ag nanoparticles should be taken into account. Olha Hrytsenko, Dmytro Hrytsenko, Vitaliy Shvalagin, Galyna Grodziuk, and Nataliia Andriushyna Copyright © 2017 Olha Hrytsenko et al. All rights reserved. Low Temperature Oxidation of Carbon Monoxide over Mesoporous Au-Fe2O3 Catalysts Mon, 10 Jul 2017 00:00:00 +0000 Low temperature active and stable mesoporous Au (0.1, 0.2, 0.5, and 1.0 wt.%) supported α-Fe2O3 catalysts were prepared via deposition-precipitation method. The H2-pretreated catalyst with 0.5 wt.% Au loading offered CO conversion of 100% at 323 K and showed continual activity for at least 120 h. X-ray diffraction and transmission electron microscopy analysis indicate that Au species were highly dispersed as nanoparticles (20–40 nm) on the surface of α-Fe2O3 support even after thermal treatment at 773 K. The N2-physisorption measurements show that the synthesized α-Fe2O3 support and Au-Fe2O3 nanocomposites possessed mesopores with high specific surface area of about 158 m2 g−1. X-ray photoelectron spectroscopy and H2-TPR results reveal that the Au species exist in metallic and partially oxidized state due to strong interaction with the support. Effective Au-Fe2O3 interaction resulted in a high activity for Au nanoparticles, locally generated by the thermal treatment at 773 K in air. Abdulmohsen Ali Alshehri and Katabathini Narasimharao Copyright © 2017 Abdulmohsen Ali Alshehri and Katabathini Narasimharao. All rights reserved. Improving the Efficiency of Dye-Sensitized Solar Cells by Growing Longer ZnO Nanorods on TiO2 Photoanodes Sun, 09 Jul 2017 09:21:42 +0000 By increasing the temperature of hydrothermal reactions from 70 to 100°C, vertically aligned ZnO nanorods were grown on the TiO2 thin film in the photoanode of dye-sensitized solar cells (DSSCs) as the blocking layer to reduce the electron back recombinations at the TiO2/electrolyte interfaces. The length effects of ZnO nanorods on the photovoltaic performances of TiO2 based DSSCs were investigated by means of scanning electron microscope, X-ray diffractometer, photoluminescence spectrophotometer, and the photocurrent-voltage measurement. Under the illumination of 100 mW/cm2, the power conversion efficiency of DSSC with ZnO nanorods decorated TiO2 thin film as its photoanode can be increased nearly fourfold from 0.27% to 1.30% as the length of ZnO nanorods increases from 300 to 1600 nm. The enhanced efficiency of DSSC with ZnO nanorods decorated TiO2 thin film as the photoanode can be attributed to the larger surface area and the lower defect density in longer ZnO nanorods, which are in favor of more dye adsorption and more efficient transport in the photoanode. Bao-gai Zhai, Long Yang, and Yuan Ming Huang Copyright © 2017 Bao-gai Zhai et al. All rights reserved. Synthesis of Fluorescent Carbon Dots by Gastrointestinal Fluid Treatment of Mongolia Har Gabur Sun, 09 Jul 2017 06:35:33 +0000 Har Gabur is the carbide obtained from pig manure by burning. The fluorescent carbon dots (CDs) of Har Gabur were successfully synthesized through simulating the digestion process of human gastrointestinal tract. Transmission Electron Microscope (TEM) analysis showed that the average size of the prepared Har Gabur CDs was 4 nm, with good solubility in water and strong fluorescence under UV irradiation. The X-ray and Raman results showed that the Har Gabur CDs were mainly composed of oxygen “O” and carbon “C” elements, in the forms of “C=O” and “C-O.” The bond energy results showed that the nitrogen “N” atom presented as “C-N” form, which indicated that Har Gabur CDs also contain “N.” In photobleaching assay, Har Gabur CDs showed excellent light stability compared with ordinary organic dye, fluorescein, and Rhodamine B. The fluorescence intensity of Har Gabur CDs was fairly stable within a wide pH range of 3–10. When L-lysine and L-cysteine were applied for the passivation stage, the relative quantum yields were improved by 1.53 and 3.68 times, respectively. Finally, the fluorescence properties of Har Gabur CDs were tested in cells and zebrafish, illustrating that Har Gabur CD has potential in the application of biological labeling and imaging. Tegexibaiyin Wang, Wen Zhang, Xiaofeng Zhang, Xilin Qiqige, Wuhan Qimuge, Aodeng Qimuge, Hairong Wang, Bulin Baila, Alateng Qimuge, Ming Yuan, and Jun Ai Copyright © 2017 Tegexibaiyin Wang et al. All rights reserved. Application of Nanomaterials in Stem Cell Regenerative Medicine of Orthopedic Surgery Thu, 06 Jul 2017 10:44:14 +0000 Regenerative medicine aims to achieve functional rehabilitation of tissue or cells injured through wound, disease, or aging. Recent findings suggest that nanotechnology provides advanced biomaterials with specified morphologies which can create a nanoscale extracellular environment capable of promoting the adhesion and proliferation of stem cells and accelerating stem cell differentiation in a controlled manner in tissue engineering. This review summarizes the biological effects of nanomaterials and their regenerative medicine applications in orthopedic surgery research, including bone, cartilage, tendons, and nerve tissue engineering. Su Pan, Hongmei Yu, Xiaoyu Yang, Xiaohong Yang, Yan Wang, Qinyi Liu, Liliang Jin, and Yudan Yang Copyright © 2017 Su Pan et al. All rights reserved. Comparative Study of One-Step Cross-Linked Electrospun Chitosan-Based Membranes Thu, 06 Jul 2017 09:15:11 +0000 Chitosan membranes are widely applied for tissue engineering; however, a major drawback is their low resistance in aqueous phases and therefore the structure collapses impeding their long-term use. Although there is extensive research, because of chitosan’s importance as a biomaterial, studies involving chitosan-based membranes are still needed. Herein, a detailed investigation of diverse chemical routes to cross-link fibers in situ by electrospinning process is described. In case of using genipin as cross-linker, a close relationship with the content and the mean diameter values is reported, suggesting a crucial effect over the design of nanostructures. Also, the physical resistance is enhanced for the combination of two types of methods, such as chemical and physical methods. Cross-linked fibers upon exposure to long wave ultraviolet A (UVA light) change their morphology, but not their chemical composition. When they are incubated in aqueous phase for 70 days, they show an extensive improvement of their macrostructural integrity which makes them attractive candidates for tissue engineering application. As a result, the thermal properties of these materials reveal less crystallinity and higher temperature of degradation. Yanet E. Aguirre-Chagala, Laura B. Pavón-Pérez, Víctor Altuzar, Jorge G. Domínguez-Chávez, Severino Muñoz-Aguirre, and C. Mendoza-Barrera Copyright © 2017 Yanet E. Aguirre-Chagala et al. All rights reserved. Effects of Ultrasound Irradiation on the Preparation of Ethyl Cellulose Nanocapsules Containing Spirooxazine Dye Thu, 06 Jul 2017 08:22:31 +0000 This article presents the influence of low frequency, high intensity ultrasonic irradiation on the characteristics (average size, polydispersity index) of ethyl cellulose nanocapsules encapsulating a photochromic dye. Photochromic nanocapsules were prepared by the emulsion-solvent evaporation method. The acoustic densities entering the system were systematically studied with respect to their abilities to modify and reduce the average sizes and polydispersity indexes of the nanocapsules. Scanning electron microscope, confocal laser microscope, and dynamic light scattering were utilised to characterise the structure, shape, size, and polydispersity of ethyl cellulose photochromic nanocapsules. We were able to tailor the size of the photochromic nanocapsules simply by varying the acoustic densities entering the system. At an acoustic density of 1.5 W/mL and 60 s of continuous irradiation, we were able to prepare an almost monodispersed population of the nanocapsules with an average size of 193 nm. Julija Volmajer Valh, Simona Vajnhandl, Lidija Škodič, Aleksandra Lobnik, Matejka Turel, and Bojana Vončina Copyright © 2017 Julija Volmajer Valh et al. All rights reserved. Investigation of the Influence of Ni Doping on the Structure and Hardness of Ti-Ni-C Coatings Thu, 06 Jul 2017 00:00:00 +0000 Nanocomposite nc-TiC/a-C:H thin films exhibit unique combination of mechanical properties, high hardness, low friction, and wear. Selective doping by weak-carbide forming element can be used in order to specifically design the physical and chemical properties of nc-TiC/a-C:H coatings. In this paper we report on an effect of nickel addition on structure and hardness of the nc-TiC/a-C:H coatings. The effect of Ni alloying on the coating structure under conditions of DCMS and HiPIMS depositions was studied. The coating structure was correlated with the coating hardness. The grain size, the grain carbon vacancy concentration, and the mean grain separation were found to be the key parameters determining the coating hardness. Ni doping proved to have a significant effect on the coating microstructure which resulted in changes of the hardness of the deposited coatings. J. Daniel, P. Souček, K. Bernátová, L. Zábranský, M. Stupavská, V. Buršíková, and P. Vašina Copyright © 2017 J. Daniel et al. All rights reserved. Effects of Milling pH and Hydrothermal Treatment on Formation of Nanostructured Boehmite Binder for Alumina Extrusion Wed, 05 Jul 2017 07:21:03 +0000 The in situ formation of nanostructured aluminum hydroxides on the surface of alumina particles, which can work as inorganic binder, was reported in this paper. The effect of the suspension pH during milling of alumina powder and subsequent hydrothermal treatment for the hydroxide formation and microstructure was depicted. Under acidic pH condition, the formation of hydroxides was not observed. When the pH of suspension changed from acidic to basic during milling, bayerite [Al(OH)3] nanoparticles were formed, but only a fraction of this hydroxide was converted to boehmite (AlOOH) during subsequent hydrothermal treatment. The aluminum hydroxide and oxyhydroxide formed in this condition improved the smoothness of extruded rods and the strength of presintered segments. For the powder milled under basic pH condition, the mechanochemically formed bayerite was completely converted into boehmite nanoparticles during the hydrothermal treatment. The presence of boehmite nanoparticles contributed to improving plasticity during extrusion, which allowed the reduction of organic binder and increased the strength of presintered alumina rods. Maurício Batista de Lima, Marcela Bergamaschi Tercini, Sydney Ferreira Santos, Fernando dos Santos Ortega, and Humberto Naoyuki Yoshimura Copyright © 2017 Maurício Batista de Lima et al. All rights reserved. Enhanced Radiosensitization Effect of Curcumin Delivered by PVP-PCL Nanoparticle in Lung Cancer Wed, 05 Jul 2017 00:00:00 +0000 Curcumin, the principal polyphenolic curcuminoid, has been reported in numerous studies for its antitumor effect in a series of cancers. It is also reported that curcumin possesses radiosensitization effect in some cancers. However, the poor solubility and unsatisfied bioavailability of curcumin significantly undermine its potential application. Here we prepared curcumin loaded nanoparticles by employing PVP-PCL as drug carrier. Characterization studies indicated the satisfied drug loading efficiency and a sustained in vitro release pattern. Quantification uptake study showed that the uptake efficiency of Cum-NPs by lung cancer cells was time- and dose-dependent. In vitro anticancer study demonstrated the superior cytotoxic effect of Cum-NPs with stronger apoptotic induction over free Cum. Most importantly, there is almost no report on the radiosensitization effect of curcumin loaded nanoparticles. Here, Cum-NPs led to more inhibition of the colony forming ability of A549 cells as compared to the equivalent concentration of free Cum as shown in clonogenic assay. Furthermore, Cum-NPs are much more effective in enhancing the tumor growth inhibitory effect of radiation therapy in a A549 xenograft model. Therefore, results from the current study seem to be the first report on the radiosensitization effect of Cum-NPs and paved the way for a curcumin nanodrug delivery system as a potential radiation adjuvant. Cuixia Wen, Yun Zhou, Chong Zhou, Yifan Zhang, Xiang Hu, Jun Li, and Haitao Yin Copyright © 2017 Cuixia Wen et al. All rights reserved. Ab Initio Study of Electronic Transport in Cubic-HfO2 Grain Boundaries Wed, 05 Jul 2017 00:00:00 +0000 In polycrystalline materials the grain boundaries (GBs) are particularly important as they can act as a sink for atom defects and impurities, which may drive structural transformation of the materials and consequently modify their properties. Characterising the structure and properties of GBs is critical for understanding and controlling material property. Here, we investigated how GBs can modify the structural, electronic, and transport properties of the polycrystalline material . In general, grain boundaries are considered to be detrimental to the physical stability and electronic transport in . Anyway, studying by first principles the two most stable and common types of GBs, the tilt and the twist, we found substantial differences on the impact they have on the material properties. In fact, while tilt defects create channels of different sizes and shapes in hafnia along which the electronic transport is stronger in relation to leakage current through GBs, twist defects create a sort of amorphous structure that tends to resemble the bulk and which is independent of the number of rotated planes/atoms. Elena Degoli, Eleonora Luppi, and Nathalie Capron Copyright © 2017 Elena Degoli et al. All rights reserved. Synthesis, Characterization, and Catalytic Performance of Sb2Se3 Nanorods Tue, 04 Jul 2017 08:10:12 +0000 Antimony selenide has many potential applications in thermoelectric, photovoltaic, and phase-change memory devices. A novel method is described for the rapid and scalable preparation of antimony selenide (Sb2Se3) nanorods in the presence of hydrazine hydrate and/or permanganate at 40°C. Crystalline nanorods are obtained by the addition of hydrazine hydrate in a reaction mixture of antimony acetate and/or chloride and sodium selenite in neutral and basic media, while amorphous nanoparticles are formed by the addition of KMnO4 in a reaction mixture of antimony acetate/chloride and sodium selenite. The powder X-ray diffraction pattern confirms orthorhombic phase crystalline Sb2Se3 for the first and second reactions with lattice parameters  nm,  nm, and  nm and amorphous Sb2Se3 for the third reaction. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM) images show the diameter of nanorods for the first and second reactions to be in the order of 100 nm to 150 nm and about 20 nm particles for the third reaction. EDX and XPS suggest that the nanorods are pure Sb2Se3. The UV-vis analysis indicates a band gap of 4.14 and 4.97 eV for the crystalline and amorphous Sb2Se3, respectively, corresponding to a blue shift. The photocatalytic study shows that the decolorization of Rhodamine in solution by nanoparticles is slightly greater than nanorods. Ning Hu, Marcos A. Cheney, Younes Hanifehpour, Sang Woo Joo, and Bong-Ki Min Copyright © 2017 Ning Hu et al. All rights reserved. Polypropylene Carbon Nanotubes Nanocomposites: Combined Influence of Block Copolymer Compatibilizer and Melt Annealing on Electrical Properties Tue, 04 Jul 2017 07:40:21 +0000 We study the influence of melt annealing and the presence of a block copolymer compatibilizer on the electrical properties of polypropylene carbon nanotubes (CNT) nanocomposites from the DC limit to microwave frequencies and link it to the morphological details. We show that the compatibilizer concentration controls three types of morphologies: separate CNT agglomerates, a network of well dispersed but interconnected CNT, and individualized but separate nanotubes. This explains why conductivity reaches an optimum over the whole frequency range at a low compatibilizer concentration. We model the corresponding structures by a semiquantitative schematic equivalent electrical circuit. A key outcome of the work is the understanding and control of dispersion mechanisms in order to optimize the electrical performances for efficient EMI shielding depending on the targeted frequency range. Aline Emplit, Fang Fang Tao, Pascale Lipnik, Guido Heunen, Christian Bailly, and Isabelle Huynen Copyright © 2017 Aline Emplit et al. All rights reserved. Ecobiophysical Aspects on Nanosilver Biogenerated from Citrus reticulata Peels, as Potential Biopesticide for Controlling Pathogens and Wetland Plants in Aquatic Media Thu, 29 Jun 2017 00:00:00 +0000 In recent years, a considerable interest was paid to ecological strategies in management of plant diseases and plant growth. Metallic nanoparticles (MNPs) gained considerable interest as alternative to pesticides due to their interesting properties. Green synthesis of MNPs using plant extracts is very advantageous taking into account the fact that plants are easily available and eco-friendly and possess many phytocompounds that help in bioreduction of metal ions. In this research work, we phytosynthesized AgNPs from aqueous extract of Citrus reticulata peels, with high antioxidant, antibacterial, and antifungal potential. These “green” AgNPs were characterized by modern biophysical methods (absorption and FTIR spectroscopy, AFM, and zeta potential measurements). The nanobioimpact of Citrus-based AgNPs on four invasive wetland plants, Cattail (Typha latifolia), Flowering-rush (Butomus umbellatus), Duckweed (Lemna minor), and Water-pepper (Polygonum hydropiper), was studied by absorption spectroscopy, by monitoring the spectral signature of chlorophyll. The invasive plants exhibited different behavior under AgNP stress. Deep insights were obtained from experiments conducted on biomimetic membranes marked with chlorophyll a. Our results pointed out the potential use of Citrus-based AgNPs as alternative in controlling pathogens in aqueous media and in management of aquatic weeds growth. Marcela Elisabeta Barbinta-Patrascu, Nicoleta Badea, Camelia Ungureanu, Stefan Marian Iordache, Marioara Constantin, Violeta Purcar, Ileana Rau, and Cristian Pirvu Copyright © 2017 Marcela Elisabeta Barbinta-Patrascu et al. All rights reserved. Photoregulation of Gold Nanoparticles Stabilized in a Diacetylenic Nanocapsule Wed, 28 Jun 2017 00:00:00 +0000 The results of releasing a drug in a burst are unpredictable and one of the inherent drawbacks of using nanocarriers. Here, photoresponsive cationic gold nanoparticles to stabilize diacetylenic nanocapsules enabling photoregulated release of payloads are reported. The fabrication of these nanocapsules relied on an electrostatic interaction of a negatively charged diacetylenic core and a positively charged gold nanoparticle shell. Gold nanoparticles with photoresponsive ligands on their surfaces act as both hydrophobic core stabilizers and gatekeepers of the nanocapsules, while their polydiacetylene cores serve as hydrophobic drug carriers that can be tuned using UV irradiation. The morphology of nanocapsules was analyzed using TEM and dynamic light scattering. The resultant nanocapsules had a spherical shape with an average diameter of 152.9 ± 6.7 nm. Upon UV irradiation, the nanocapsules lost their integrity and an encapsulated model compound was released through diffusion. The release of a hydrophobic molecule was irradiation time dependent and thereby controllable. This light-triggered release provides an alternative strategy for controlled drug delivery. Saowalak Somjid, Apiwat Chompoosor, Somdej Kanokmedhakul, and Saowapak Teerasong Copyright © 2017 Saowalak Somjid et al. All rights reserved. Effect of Varying the Semiconducting/Metallic Tube Ratio on the Performance of Mixed Single-Walled Carbon Nanotube Network Gas Sensors Wed, 28 Jun 2017 00:00:00 +0000 The sensing properties of mixed networks consisting of semiconducting and metallic single-walled carbon nanotubes (SWCNTs) have been found to largely vary depending on the ratio of semiconducting to metallic tubes. Solution-deposited 99% semiconductor-enriched nanotube networks exhibited a sensitivity of 1.908%/ppm, whereas the unenriched 66% and 90% enriched samples exhibited a sensitivity of 0.027%/ppm and 0.113%/ppm, respectively. These results suggest that it is extremely important to minimize the metallic pathways to achieve high sensitivity. After an oxygen plasma treatment, the unenriched 66% sample exhibited a 526% increase in sensitivity (0.142%/ppm) compared to the untreated one, whereas the 90% device demonstrated a sensitivity of 1.521%/ppm, which corresponds to an improvement in the sensitivity of 13.5 times the pristine 90% sample. In addition, the plasma-treated sensors exhibited a much faster response time than the untreated one. The significant improvement in the performance of the highly enriched network sensors was explained by the large increase in the anchoring sites for ammonia molecules on the surface of the semiconducting single-walled CNTs and the faster charge transfer from absorbed molecules. Sung Joon Min, Jin Woong Kim, Joon Hyub Kim, Joon Hyock Choi, Chan Won Park, and Nam Ki Min Copyright © 2017 Sung Joon Min et al. All rights reserved. Sodium Hypochlorite as Fluorotic Dentin Pretreatment of Two-Step Self-Etch Adhesive with Silver Nanoparticle: Atomic Force Microscope and Adhesive Microtensile Bond Strength Evaluation Tue, 27 Jun 2017 09:04:57 +0000 The objective of this work was to evaluate the effect of pretreatment with commercial sodium hypochlorite, 5.25%, with a self-etch adhesive (Optibond Versa) in its original formula and with the incorporation of silver nanoparticles (NaAg) on fluorotic dentin. 240 human molars were classified according to fluorosis severity with Thylstrup-Fejerskov Index (TFI) and subdivided into three study subgroups according to the adhesive technique: () self-etch (SE) control subgroup; () NaOCl/SE subgroup; () NaOCl/SE + NaAg subgroup. The nanostructural characteristics were observed by AFM, μTBS was tested, and hybrid layer formation was observed by SEM. One-way analyses of variance (ANOVA) and Tukey-Kramer post hoc tests were used. No statistically significant differences were found in roughness values in any of the subgroups and subgroups studied. Remnants of smear layer were detected in areas devoid of resin tags in SEM images of samples bonded with subgroup 2, in contrast to subgroup 3. No statistically significant difference between any of the results was found in μTBS and a greater number of adhesive failures were observed. The results show that the pretreatment technique of 5.25% NaOCl and the incorporation of NaAg to the self-adhesive system do not produce a surface more adequate for a better adhesion. Ana-Josefina Monjarás-Ávila, Norma-Verónica Zavala-Alonso, Gabriel Alejandro Martínez-Castañón, Nuria Patiño-Marín, Daniel Silva-Herzog Flores, and Facundo Ruíz Copyright © 2017 Ana-Josefina Monjarás-Ávila et al. All rights reserved.