Journal of Nanomaterials The latest articles from Hindawi © 2017 , Hindawi Limited . All rights reserved. A Fabrication Process for Emerging Nanoelectronic Devices Based on Oxide Tunnel Junctions Thu, 23 Feb 2017 11:11:51 +0000 We present a versatile nanodamascene process for the realization of low-power nanoelectronic devices with different oxide junctions. With this process we have fabricated metal/insulator/metal junctions, metallic single electron transistors, silicon tunnel field effect transistors, and planar resistive memories. These devices do exploit one or two nanometric-scale tunnel oxide junctions based on TiO2, SiO2, HfO2, Al2O3, or a combination of those. Because the nanodamascene technology involves processing temperatures lower than 300°C, this technology is fully compatible with CMOS back-end-of-line and is used for monolithic 3D integration. Dominique Drouin, Gabriel Droulers, Marina Labalette, Bruno Lee Sang, Patrick Harvey-Collard, Abdelkader Souifi, Simon Jeannot, Stephane Monfray, Michel Pioro-Ladriere, and Serge Ecoffey Copyright © 2017 Dominique Drouin et al. All rights reserved. Preparation and Characterisation of Highly Stable Iron Oxide Nanoparticles for Magnetic Resonance Imaging Thu, 23 Feb 2017 09:56:45 +0000 Magnetic nanoparticles produced using aqueous coprecipitation usually exhibit wide particle size distribution. Synthesis of small and uniform magnetic nanoparticles has been the subject of extensive research over recent years. Sufficiently small superparamagnetic iron oxide nanoparticles easily permeate tissues and may enhance the contrast in magnetic resonance imaging. Furthermore, their unique small size also allows them to migrate into cells and other body compartments. To better control their synthesis, a chemical coprecipitation protocol was carefully optimised regarding the influence of the injection rate of base and incubation times. The citrate-stabilised particles were produced with a narrow average size range below 2 nm and excellent stability. The stability of nanoparticles was monitored by long-term measurement of zeta potentials and relaxivity. Biocompatibility was tested on the Caki-2 cells with good tolerance. The application of nanoparticles for magnetic resonance imaging (MRI) was then evaluated. The relaxivities and ratio calculated from MR images of prepared phantoms indicate the nanoparticles as a promising -contrast probe. David Kovář, Aneta Malá, Jitka Mlčochová, Michal Kalina, Zdenka Fohlerová, Antonín Hlaváček, Zdeněk Farka, Petr Skládal, Zenon Starčuk Jr., Radovan Jiřík, Ondřej Slabý, and Jaromír Hubálek Copyright © 2017 David Kovář et al. All rights reserved. Study of the Dynamic Uptake of Free Drug and Nanostructures for Drug Delivery Based on Bioluminescence Measurements Thu, 23 Feb 2017 00:00:00 +0000 The past two decades have witnessed the great growth of the development of novel drug carriers. However, the releasing dynamics of drug from drug carriers in vivo and the interactions between cells and drug carriers remain unclear. In this paper, liposomes were prepared to encapsulate D-luciferin, which was the substrate of luciferase and served as a model drug. Based on the theoretical calculation of active loading, methods of preparation for liposomes were optimized. Only when D-luciferin was released from liposomes or taken in by the cells could bioluminescence be produced under the catalysis of luciferase. Models of multicellular tumor spheroid (MCTS) were built with 4T1-luc cells that expressed luciferase stably. The kinetic processes of uptake and distribution of free drugs and liposomal drugs were determined with models of cell suspension, monolayer cells, MCTS, and tumor-bearing nude mice. The technology platform has been demonstrated to be effective for the study of the distribution and kinetic profiles of various liposomes as drug delivery systems. Zhongjian Fang, Houchao Xu, Xiangjun Ji, Congbiao Liu, Kai Wang, Xiaoqing Qian, and Wencong Zhou Copyright © 2017 Zhongjian Fang et al. All rights reserved. Optical Nonlinear Properties of Gold Nanoparticles Synthesized by Laser Ablation in Polymer Solution Wed, 22 Feb 2017 09:08:58 +0000 In the present study, gold nanoparticles were synthesized in various polymer solutions by means of employing laser ablation technique at the same ablation time. Specifically, gold nanoparticles were synthesized in polyethylene glycol and chitosan solutions, in order to compare the effects of the liquid media which served as stabilizers for particle size and volume fraction of nanoparticles. In addition, this experiment was repeated in distilled water for reference purposes. As the findings indicated, the particle size which was obtained in polyethylene glycol was about 7.49 nm, that is, smaller than those of chitosan solution and distilled water, respectively. In contrast, it was observed that the volume fraction of gold nanoparticles increased in polyethylene glycol in comparison with the other media which indicated an effect on the formation of NPs. On the other hand, Z-scan technique was employed to measure the nonlinear refractive index and nonlinear absorption coefficient of nanofluids containing gold nanoparticles. Consequently, the nonlinear properties of nanofluids pointed to a significant contribution with the number of nanoparticles observed in fluids and both optical nonlinear parameters were observed to increase by means of a prior increase in the volume fraction of Au-NPs in polyethylene glycol solution. M. Tajdidzadeh, A. B. Zakaria, Z. Abidin Talib, A. S. Gene, and S. Shirzadi Copyright © 2017 M. Tajdidzadeh et al. All rights reserved. New Class of Antimicrobial Agents: SBA-15 Silica Containing Anchored Copper Ions Wed, 22 Feb 2017 07:23:16 +0000 The paper is about a new class of antimicrobial functional nanomaterials. Proposed compounds are based on SBA-15 porous silica matrices and contain anchored copper ions. Thanks to the immobilization of functional groups the compounds are safer for environment than commonly used disinfectant agents. We prepared and examined silica based materials containing two concentrations of copper-containing groups: 10 and 5%. For the reference we prepared samples containing free-standing CuO molecules in the structure and checked their antimicrobial properties. Antibacterial effect of considered SBA-15-Cu material was tested on Escherichia coli bacteria. Antimicrobial tests were applied for the pure form of the material and as modifying agents for plastics. The obtained results showed that the sample with lower concentration of active copper-containing groups has stronger antimicrobial properties than the one with higher concentration of copper. Interestingly, silica containing free-standing CuO molecules has no antimicrobial properties. Considering the obtained results, we can conclude that the most probable antimicrobial mechanism in this case is an oxidation stress. When a plastic modifier is applied the material is enriched with bacterial inhibitory properties. It seems that SBA-15 silica containing low concentration of anchored copper ions is promising in terms of its antibacterial property and biomaterial potential for commercial use. Lukasz Laskowski, Magdalena Laskowska, Krzysztof Fijalkowski, Henryk Piech, Jerzy Jelonkiewicz, Marta Jaskulak, Adam Gnatowski, and Mateusz Dulski Copyright © 2017 Lukasz Laskowski et al. All rights reserved. Production and Properties of Carbon Nanotube/Cellulose Composite Paper Tue, 21 Feb 2017 07:16:09 +0000 Multiwalled carbon nanotube/cellulose composite papers have been prepared by mixing the cellulose with MWNT/gelatin solution and drying at room temperature. The CNTs form an interconnected network on the cellulose paper and as a result CNT paper sheet exhibits enhanced electrical properties and thermal stabilities. It is found that both sides of CNT paper sheet have the uniform electrical conductivities. The sheet exhibits strong microwave absorption in the microwave range of 10.5 GHz. The CNT/cellulose paper is as flexible and mechanically tough as the pure cellulose paper. This work provides a novel and simple pathway to make CNT/cellulose sheet as multifunctional biomaterials for electronic, magnetic, semiconducting, and biotechnological applications. Kazi Hanium Maria and Tetsu Mieno Copyright © 2017 Kazi Hanium Maria and Tetsu Mieno. All rights reserved. WO3 Nanowires on Graphene Sheets as Negative Electrode for Supercapacitors Mon, 20 Feb 2017 08:29:04 +0000 WO3 nanowires directly grown on graphene sheets have been fabricated by using a seed-mediated hydrothermal method. The morphologies and electrochemical performance of WO3 films prepared by different process were studied. The results show that the precoated nanoseeds and graphene sheets on graphite electrode provide more reactive centers for the nucleation and formation of uniform WO3 nanowires. The WO3 nanowires electrode exhibits a high area specific capacitance of 800 mF cm−2 over negative potential range from −1.0 V to 0 V versus SCE in 1 M Li2SO4 solution. A high performance electrochemical supercapacitor assembled with WO3 nanowires as negative electrode and PANI/MnO2 as positive electrodes over voltage range of 1.6 V displays a high volumetric capacitance of 2.5 F cm−3, which indicate great potential applications of WO3 nanowires on graphene sheets as negative electrode for energy storage devices. Bo Liu, Yan Wang, Hong-Wu Jiang, and Ben-Xue Zou Copyright © 2017 Bo Liu et al. All rights reserved. Preparation of N-Doped Composite Shell Encapsulated Iron Nanoparticles and Their Magnetic, Adsorptive, and Photocatalytic Properties Mon, 20 Feb 2017 00:00:00 +0000 The N-doped composite shell encapsulated iron nanoparticles (CSEINPs) were prepared by DC arc discharge under nitrogen at 800°C, using the anode with high Fe content and good homogeneity. The morphology, microstructure, composition, and some properties of the N-doped CSEINPs were characterized by various characterization techniques. The results revealed that the shells of the N-doped CSEINPs were composed of homogeneously amorphous structure containing C, Fe, O, and N elements; the saturation magnetization (Ms) and coercivity (Hc) of them at room temperature were 130 emu/g and 194 Oe, respectively. Due to the surface structure and the electrostatic interaction, the N-doped CSEINPs are employed to remove methylene blue (MB) from the waste solution, and they exhibited high adsorption properties and photocatalytic activity under irradiation of visible light (IVL). The kinetics of adsorption of MB on the N-doped CSEINPs was investigated and the recycling test was carried out. The formation mechanism of the N-doped CSEINPs is discussed briefly. Caijing Shi, Lan Cui, Kui Lin, Qianjin Guo, Fan Zhang, Fengxiang Hu, Sayyar Ali Shah, Xitao Wang, Xiaoping Chen, and Shen Cui Copyright © 2017 Caijing Shi et al. All rights reserved. Skin Cancer and Its Treatment: Novel Treatment Approaches with Emphasis on Nanotechnology Sun, 19 Feb 2017 11:42:36 +0000 The life expectancy in the Western world is increasing for a long time, which is the courtesy of a higher life standard, a more thorough hygiene, and, of course, the progress of modern medicine. Nevertheless, one of the illnesses that still proves to be a great challenge regardless of the recent advancements in medicine is cancer. Skin cancer is, according to the World Health Organization, the most common malignancy for the white population. The beginning of the paper offers a brief overview of the latest available information concerning epidemiology, aetiology, diagnostics, and treatment options for skin cancer, whereas the rest of the article deals with modern approaches to skin cancer treatment, highlighting recent development of nanotechnology based treatment approaches. Among these, we focus especially on the newest nanotechnological approaches combined with chemotherapy, a field which specialises in target specificity, drug release control, and real time monitoring with the goal being to diminish unwanted side effects and their severity, achieving a cheaper treatment and a generally more efficient chemotherapy. The field of nanotechnology is a rapidly developing one, judging by already approved clinical studies or by new theranostic agents that combine both the therapeutic and diagnostic modalities. Kristjan Orthaber, Matevž Pristovnik, Kristijan Skok, Barbara Perić, and Uroš Maver Copyright © 2017 Kristjan Orthaber et al. All rights reserved. Dilute Alkali and Hydrogen Peroxide Treatment of Microwave Liquefied Rape Straw Residue for the Extraction of Cellulose Nanocrystals Sun, 19 Feb 2017 00:00:00 +0000 Microwave-assisted liquefaction of rape straw in methanol was conducted to collect the liquefied residues for the extraction of cellulose nanocrystals (CNCs). The liquefied residue with content of 23.44% from 180°C/7.5 min was used to fibrillate CNCs with dilute alkali (2% NaOH) and hydrogen peroxide (5% H2O2) treatments, followed by ultrasonication for 15 min. The FT-IR spectra and SEM images revealed that the liquefied residue from 180°C/7.5 min exhibited a relatively homogeneous texture and a huge surface with cellulose as core structure. The retained hemicelluloses and other impurities in the liquefied residue were eliminated by 2% NaOH treatment, and the surface and accessibility of the alkali treated sample were significantly increased by 5% H2O2 treatment. The TEM images confirmed the CNCs had an average diameter of 12.59 nm. The CNCs had good thermal stability with a maximum weight loss temperature of 376.5°C. Xingyan Huang, Cornelis F. De Hoop, Feng Li, Jiulong Xie, Chung-Yun Hse, Jinqiu Qi, Yongze Jiang, and Yuzhu Chen Copyright © 2017 Xingyan Huang et al. All rights reserved. Biocompatibility and Toxicity of Polylactic Acid/Ferrosoferric Oxide Nanomagnetic Microsphere Sun, 19 Feb 2017 00:00:00 +0000 Magnetic targeted drugs delivery system (MTDDS) is a new targeted drug system, which can greatly reduce the dosage and improve the therapeutic efficiency of medicine. Currently superparamagnetic ferric oxide plays important function as targeted drug in the treatment of tumors, but cytotoxicity was still regarded as side effect in the process of drug. In this paper, we take advantage of drug carrier (ferric oxide) toxicity controlling cancer cell growth in cancer treatment, increasing targeted drug efficiency. We applied the modified chemical precipitation method to prepare polylactic acid (PLA) coated high-purity superparamagnetic Fe3O4 nanoparticles for targeted drug, characterized PLA/Fe3O4 microspheres physical and chemical properties, and then investigated cytotoxicity influence of PLA/Fe3O4 nanomagnetic microspheres as carrier for normal liver cells (7701) and liver cancer cells (HePG2) in different concentration; results of MTT and hemolysis and micronucleus test showed that carrier restrained the growth of HePG2 in special concentration, meanwhile the proliferation rate of liver cells was not affected. The study demonstrates that compared with liver cell, liver cancer cells (HepG2) are easy to be disturbed by PLA/Fe3O4 nanomagnetic microsphere, which have higher sensitivity and absorption ability. We hope to take advantage of the susceptible property of cancer cells for carriers to improve targeted drug function. Hongzhao Xiang, Yuanhua Mu, Chengbo Hu, and Xiaobing Luo Copyright © 2017 Hongzhao Xiang et al. All rights reserved. Electromagnetic, Morphological, and Electrical Characterization of POMA/Carbon Nanotubes-Based Composites Thu, 16 Feb 2017 12:35:20 +0000 This study involves the preparation of conducting composites based on poly(o-methoxyaniline) (POMA) and carbon nanotubes (CNT) and the evaluation of them as radar absorbing materials (RAM), in the frequency range of 8.2–12.4 GHz (X-band). The composites were obtained by synthesis in situ of POMA in the presence of CNT (0.1 and 0.5 wt% in relation to the o-methoxyaniline monomer). The resulting samples—POMA/CNT-0.1 wt% and POMA/CNT-0.5 wt%—were incorporated in an epoxy resin matrix in the proportion of 1 and 10 wt%. FT-IR analyses show that the POMA was successfully synthesized on the CNT surface. SEM analyses show that the synthesized POMA recovered all CNT surface. Electrical conductivity measurements show that the CNT contributed to increase the conductivity of POMA/CNT composites (1.5–6.7 S·cm−1) in relation to the neat POMA (5.4 × 10−1 S·cm−1). The electromagnetic characterization involved the measurements of complex parameters of electrical permittivity () and magnetic permeability (), using a waveguide in the X-band. From these experimental data reflection loss (RL) simulations were performed for specimens with different thicknesses. The complex parameters show that the CNT in the composites increased and . These results are attributed to the CNT network formation into the composites. Simulated RL curves of neat POMA and POMA/CNT in epoxy resin show the preponderant influence of POMA on all RL curves. This behavior is attributed to the efficient CNT recovering by POMA. RL results show that the composite based on 10 wt% of POMA/CNT-0.5 wt% in epoxy resin (9 mm thickness) presents the best RL results (87% of attenuation at 12.4 GHz). Simone de Souza Pinto and Mirabel Cerqueira Rezende Copyright © 2017 Simone de Souza Pinto and Mirabel Cerqueira Rezende. All rights reserved. One-Electron Conical Nanotube in External Electric and Magnetic Fields Wed, 15 Feb 2017 00:00:00 +0000 The effects of variation of the aperture angle on spectral and magnetic properties of one-electron nanotube of the axially symmetrical conical shape in the presence of the electric and magnetic fields have been investigated based on a numerical solution of the Schrödinger equation in the effective mass approximation. We show that the energy spectrum and the magnetic dipole moment of the structure are changed dramatically with increase of the cone’s aperture angle due to the interplay between the diamagnetic and centrifugal forces, which push the electron at opposite directions. Particularly, the energy levels close to the ground state become quasi-degenerate, owing to a change of the hidden symmetry, induced by the magnetic field in this structure, when its morphology is converted from the cylindrical type to the conical one and the Aharonov-Bohm oscillations of the ground state energy and of the magnetic dipole moment are quenched. We found additionally that any weak electric field breaks this hidden symmetry, splits quasi-degenerate state, and restores the Aharonov-Bohm oscillations. L. F. Garcia, W. Gutiérrez, and I. D. Mikhailov Copyright © 2017 L. F. Garcia et al. All rights reserved. Enhancement of Thermal Stability and Cycling Performance of Lithium-Ion Battery at High Temperature by Nano-ppy/OMMT-Coated Separator Wed, 15 Feb 2017 00:00:00 +0000 Nanopolypyrrole/organic montmorillonite- (nano-ppy/OMMT-) coated separator is prepared by coating nano-ppy/OMMT on the surface of polyethylene (PE). Nano-ppy/OMMT-coated separator with three-dimensional and multilayered network structure is beneficial to absorb more organic electrolyte, enhancing the ionic conductivity (reach 4.31 ). Meanwhile, the composite separator exhibits excellent thermal stability and mechanical properties. The strong covalent bonds (Si-F) are formed by the nucleophilic substitution reaction between F− from the thermal decomposition and hydrolysis of LiPF6 and the covalent bonds (Si-O) of nano-ppy/OMMT. The Si-F can effectively prevent the formation of HF, POF3, and LiF, resulting in the inhibition of the disproportionation of Mn3+ in LiNi1/3Co1/3Mn1/3O2 material as well as reducing the internal resistance of the cell. Therefore, the nano-ppy/OMMT-coated separator exhibits outstanding capacity retention and cycling performance at 80°C. Shuo Yang, Huiya Qin, Xuan Li, Huijun Li, and Pei Yao Copyright © 2017 Shuo Yang et al. All rights reserved. Atomic Force Microscopy for Collagen-Based Nanobiomaterials Wed, 15 Feb 2017 00:00:00 +0000 Novel nanobiomaterials are increasingly gaining ground in bioengineering research. Among the numerous biomaterials, collagen-nanobiomaterials, such as collagen thin films, are of great interest since they present a wide range of applications in the fields of biomaterials, tissue engineering, and biomedicine. Collagen type I is the most abundant protein within extracellular matrix and, due to its unique characteristics, is widely used as biomaterial. A thorough characterization of the structure and properties of nanomaterials can be achieved by Atomic Force Microscopy (AFM). AFM is a very powerful tool which can be used to obtain qualitative or quantitative information without destroying the collagen fibrillar structure. This mini review covers issues related to the use of AFM for studying the structure and mechanical properties of collagen-based nanobiomaterials, collagen-substrate interactions during the formation of collagen thin films, collagen-cells interactions, and the collagen-optical radiation interactions. Andreas Stylianou Copyright © 2017 Andreas Stylianou. All rights reserved. Bulk Heterojunction Solar Cell Devices Prepared with Composites of Conjugated Polymer and Zinc Oxide Nanorods Mon, 13 Feb 2017 00:00:00 +0000 ZnO nanorods (Nrods) with ~20–50 nm lengths were synthesized using an aqueous solution of zinc acetate and glacial acetic acid. Bulk heterojunction solar cells were fabricated with the structure of indium tin oxide (ITO)/polyethylenedioxythiophene doped with polystyrene-sulfonic acid (PEDOT:PSS)/ZnO-Nrods + polymer/electron transport layer (ETL)/Al. Current density-voltage characterization of the resulting cells showed that, by adding an ETL and using polymers with a low band gap energy, the photoactive layer surface morphology and the device performance can be dramatically improved. Nguyen Tam Nguyen Truong, Hoa Nguyen, Phuc Huu Tran Le, Chinho Park, and Jae Hak Jung Copyright © 2017 Nguyen Tam Nguyen Truong et al. All rights reserved. Theoretical Research on Ellipsoidal Structure Methane Gas Detection Based on Near Infrared Light Sources of PbSe Quantum Dots Sun, 12 Feb 2017 00:00:00 +0000 To improve the precision and sensitivity of the detection in near infrared gas detection system, the selection of light source and design of gas chamber structure are two key links. In this paper, the near infrared (NIR) light sources fabricated with PbSe quantum dots (QDs) and a new gas cell structure using an ellipsoid reflector were designed to test the concentration of methane (CH4). The double wavelengths differential detection method was used in the paper. The signal wavelength is 1.665 μm from the NIR QD-based light source with 5.1 nm PbSe QDs. The reference wavelength is 1.943 μm from the NIR QD-based light source with 6.1 nm PbSe QDs. The experimental results show that the differential gain signal could be enhanced 80 times when the major axis, the focus, and the open length of the ellipsoid reflector are 4.18 cm, 3.98 cm, and 0.36 cm, respectively. The structure will be convenient for the signal amplifying, AD converting, and other process in the latter circuits, and therefore both the detection sensitivity and precision can be improved. Xiaoxue Xing, Yanmin Lei, Weiwei Shang, Limin Du, and Pan Guo Copyright © 2017 Xiaoxue Xing et al. All rights reserved. Fabrication of Amino Functionalized Magnetic Expanded Graphite Nanohybrids for Application in Removal of Ag(I) from Aqueous Solution Thu, 09 Feb 2017 09:42:45 +0000 Ethylenediamine functionalized magnetic expanded graphite decorated with Fe3O4 nanoparticles (MEG-NH2) was fabricated by one-pot solvothermal method. The as-prepared MEG-NH2 nanohybrids were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Zeta potential analyzer. The effects of Fe3O4 content in MEG-NH2 nanohybrids, pH, initial concentration, contact time, and dosage on adsorption properties of the MEG-NH2 nanohybrids for Ag(I) from aqueous solution were investigated by batch experiments. The pseudo-first-order and the pseudo-second-order kinetic models were utilized to study adsorption kinetics. The experimental data was also analyzed with Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models. The results show that Ag(I) was reduced to silver in the process of the adsorption by MEG-NH2 nanohybrids; the experimental data was better fitted to pseudo-second-order model and Langmuir isotherm model which revealed that the adsorption process was a chemical adsorption by the formation of silver on the surface of MEG-NH2 nanohybrids. Ying-Xia Ma, Yong-Xin Ruan, Dan Xing, Xue-Yan Du, and Pei-Qing La Copyright © 2017 Ying-Xia Ma et al. All rights reserved. Hybrid Perovskite, CH3NH3PbI3, for Solar Applications: An Experimental and Theoretical Analysis of Substitution in A and B Sites Thu, 09 Feb 2017 08:44:27 +0000 The effect of the incorporation of into the CH3 sites of the tetragonal perovskite CH3NH3PbI3 is analysed. Also, how it affects the introduction of Cd2+ cations into Pb2+ sites for a perovskite with 25 at.% of is addressed. The incorporation of into perovskite leads to a dramatic loss of crystallinity and to the presence of other phases. Moreover, the NH4PbI3 was not found. The less formation of perovskite when is incorporated is due to geometrical factors and not changes in the chemical state bonding of the ions. Also, the samples where perovskite is formed show similar band gap values. A slight increase is observed for samples with and 0.75. For the sample with , a drastic increase of the band gap is obtained. Periodic-DFT calculations agree with the experimental structural tendency when is incorporated and the density of states analysis confirmed the experimental band gap. The perovskite with 25 at.% of was selected for studying the effect of the concentration of Cd on the structural and electronic properties. The theoretical band gap values decreased with the Cd concentration where the narrowing of Cd s-states in the conduction band plays an important role. Antonio Sánchez-Coronilla, Javier Navas, Juan Jesús Gallardo, Elisa I. Martín, Desireé De los Santos, Norge C. Hernández, Rodrigo Alcántara, José Hidalgo Toledo, and Concha Fernández-Lorenzo Copyright © 2017 Antonio Sánchez-Coronilla et al. All rights reserved. Target Transportation of Auxin on Mesoporous Au/SiO2 Nanoparticles as a Method for Somaclonal Variation Increasing in Flax (L. usitatissimum L.) Thu, 09 Feb 2017 00:00:00 +0000 Development of methods for direct delivery of different bioactive substances into the cell is a promising and intensively approached area of research. It has become a subject of serious research for multidisciplinary team of scientists working in such areas as physics, biology, and biotechnology. Plant calluses were grown on medium supplemented with different nanoparticles to be used as a model for biotechnological research. Gold nanoparticles with mesoporous silica coating were used as hormone carriers, since they possess many of critical properties required for cellular transportation instrument. Some of those properties are great biocompatibility and controlled release of carried molecules. Significant changes in hormones common impact were detected. The great increase in ploidy numbers, embryogenesis, induction, and methylation level was observed when compared to the “conventional” methods of targeted hormones delivery that embrace usage of Au nanoparticles as a main hormone carrier. The authors suppose the research under consideration can provide a new pathway to the design of a novel targeted plant hormone and bioactive substances carrier. Inese Kokina, Inese Jahundoviča, Ilona Mickeviča, Marija Jermaļonoka, Jānis Strautiņš, Sergejs Popovs, Andrejs Ogurcovs, Eriks Sledevskis, Boriss Polyakov, and Vjačeslavs Gerbreders Copyright © 2017 Inese Kokina et al. All rights reserved. Reinforcement of Natural Rubber with Bacterial Cellulose via a Latex Aqueous Microdispersion Process Thu, 09 Feb 2017 00:00:00 +0000 Natural rubber (NR) composites were reinforced with bacterial cellulose (BC) to improve mechanical and physical properties. The natural rubber bacterial cellulose (NRBC) composite films were prepared via a latex aqueous microdispersion process by a thorough mixing of BC slurry with natural rubber latex (NRL). The structural morphology and chemical and physical properties of NRBC composites were investigated. The hydrophilicity, opacity, and crystallinity of the NRBC composites were significantly enhanced because of the added BC. By loading BC at 80 wt.%, the mechanical properties, such as Young’s modulus and tensile strength, were 4,128.4 MPa and 75.1 MPa, respectively, which were approximately 2,580 times and 94 times those of pure NR films, respectively, whereas the elongation at break of was decreased to 0.04 of that of the NR film. Because of its high mechanical strength and thermal stability, the NRBC composites have potential uses as high mechanical strength rubber-based products and bioelastic packaging in many applications. Sirilak Phomrak and Muenduen Phisalaphong Copyright © 2017 Sirilak Phomrak and Muenduen Phisalaphong. All rights reserved. Structural Derivative and Electronic Property of Armchair Carbon Nanotubes from Carbon Clusters Wed, 08 Feb 2017 00:00:00 +0000 The structural derivative and electronic property of carbon nanotubes from carbon clusters were investigated by density functional theory (DFT), including armchair single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs). Results show that the carbon nanotubes (CNTs) can be obtained through layer-by-layer growth from the initial structure. The structural derivative processes are quantitatively described by monitoring changes in local configuration. Electronic properties show the energy gaps of finite SWCNTs and double-walled CNTs (DWCNTs) depending on their lengths. However, the band structures of MWCNTs differ from those of SWCNTs; the band structures of DWCNTs (4, 4)@(8, 8), (5, 5)@(10, 10), and TWCNTs show metallicity, whereas those of (3, 3)@(6, 6) DWCNTs show a strong semiconductor characteristic. Analysis of the partial density of states shows that the diameters and walls of CNTs have no obvious effects on the distribution of total density of states near the Fermi level of SWCNTs and MWCNTs. Yuchao Tang, Junzhe Lu, Denghui Liu, Xuejun Yan, Chengpeng Yao, and Hengjiang Zhu Copyright © 2017 Yuchao Tang et al. All rights reserved. Comparative Evaluation of Mechanical Properties of Dental Nanomaterials Tue, 07 Feb 2017 08:40:11 +0000 This study examines the properties of nanobased dental restorative materials with nanoindentation method in a precise, repeatable, and comparable way. Microhybrid and nanohybrid composites, conventional glass ionomer materials, and light cured nanoionomer materials were utilised for the study. Specimen discs ( mm, 2 mm) were prepared to test the hardness, modulus of elasticity, yield strength, and fracture toughness values for each sample in a nanoindentation device with an atomic force microscopy add-on (). Comparative analyses were performed by one-way ANOVA and post hoc Tukey tests. The hardness and modulus of elasticity values of nanocomposite were higher (2.58 GPa and 32.86 GPa, resp.) than those of other dental materials. Although glass ionomer exhibited a hardness that was similar to a nanoionomer (0.81 versus 0.87 GPa), glass ionomer had the lowest fracture toughness value ( MPa/mm0.5). The mechanical properties of resin composites improve with additional nanoscale fillers, unlike the glass ionomer material. Cem Peskersoy and Osman Culha Copyright © 2017 Cem Peskersoy and Osman Culha. All rights reserved. Experimental Evaluation of Oxide Nanoparticles as Friction and Wear Improvement Additives in Motor Oil Mon, 30 Jan 2017 08:07:27 +0000 The effect of two nanoparticle oxides on friction and wear was studied under laboratory test conditions using a reciprocating test machine and two test configurations. The addition of these nanoparticles in base stock oil under certain conditions reduced the coefficient of friction and improved wear, but that depended on the test configuration. Examination of the rubbed surfaces showed the pronounced formation of a tribofilm in some cases, while polishing on the surface was also observed in other cases. Contact configuration is important when oxide nanoparticles are being evaluated and the conclusions about their efficacy can be vastly different. Nicholaos G. Demas, Robert A. Erck, Cinta Lorenzo-Martin, Oyelayo O. Ajayi, and George R. Fenske Copyright © 2017 Nicholaos G. Demas et al. All rights reserved. Natural Substances for the Synthesis of Silver Nanoparticles against Escherichia coli: The Case of Megaphrynium macrostachyum (Marantaceae), Corchorus olitorus (Tiliaceae), Ricinodendron heudelotii (Euphorbiaceae), Gnetum bucholzianum (Gnetaceae), and Ipomoea batatas (Convolvulaceae) Mon, 30 Jan 2017 00:00:00 +0000 The development of drug-resistant strains is rising and the search for new and novel ways of fighting new or reemerging microbes goes on. A hope of treating such multidrug-resistant infections came from plants mediated nanoparticles since nature is a generous source which provides a variety of chemical compounds that can be used for new drug discovery. Silver nanoparticles are reported to possess antiviral, antibacterial, antifungal, antiparasitic, larvicidal activity and anticancer properties. We reported green synthesis of silver nanoparticles mediated food plants Megaphrynium macrostachyum, Corchorus olitorus, Ricinodendron heudelotii, Gnetum bucholzianum, and Ipomoea batatas and their antibacterial efficacy against the Enterobacteriaceae Escherichia coli. The nature and size of the obtained nanoparticles are discussed as well as their Minimum Inhibitory Concentration (MIC) and the Minimum Bactericide Concentration (MBC) values considering their application in medical industry. Francois Eya’ane Meva, Cecile Okalla Ebongue, Simone Véronique Fannang, Marcelle Loretta Segnou, Agnes Antoinette Ntoumba, Philippe Belle Ebanda Kedi, Rudy-Evrard Njike Loudang, Andre Yonga Wanlao, Emmanuel Roland Mang, and Emmanuel Albert Mpondo Mpondo Copyright © 2017 Francois Eya’ane Meva et al. All rights reserved. Electrical Impedance Measurements of PZT Nanofiber Sensors Sun, 29 Jan 2017 08:23:18 +0000 Electrical impedance measurements of PZT nanofiber sensors were performed using a variety of methods over a frequency spectrum ranging from DC to 1.8 GHz. The nanofibers formed by electrospinning with diameters ranging from 10 to 150 nm were collected and integrated into sensors using microfabrication techniques. Special matching circuits with ultrahigh input impedance were fabricated to produce low noise, measurable sensor outputs. Material properties including resistivity and dielectric constant are derived from the impedance measurements. The resulting material properties are also compared with those of individual nanofibers being tested using conductive AFM and Scanning Conductive Microscopy. Richard Galos, Yong Shi, Zhongjing Ren, Liang Zhou, Hao Sun, Xiaoyu Su, and Jianping Yuan Copyright © 2017 Richard Galos et al. All rights reserved. Innovative Nanomaterials for Thermal Applications Sun, 29 Jan 2017 00:00:00 +0000 Yan Wang, Hua Bao, Yalin Dong, Rajib Paul, and Hua Deng Copyright © 2017 Yan Wang et al. All rights reserved. Nano-CL-20/HMX Cocrystal Explosive for Significantly Reduced Mechanical Sensitivity Sun, 29 Jan 2017 00:00:00 +0000 Spray drying method was used to prepare cocrystals of hexanitrohexaazaisowurtzitane (CL-20) and cyclotetramethylene tetranitramine (HMX). Raw materials and cocrystals were characterized using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, Raman spectroscopy, and Fourier transform infrared spectroscopy. Impact and friction sensitivity of cocrystals were tested and analyzed. Results show that, after preparation by spray drying method, microparticles were spherical in shape and 0.5–5 µm in size. Particles formed aggregates of numerous tiny plate-like cocrystals, whereas CL-20/HMX cocrystals had thicknesses of below 100 nm. Cocrystals were formed by C–HO bonding between –NO2 (CL-20) and –CH2– (HMX). Nanococrystal explosives exhibited drop height of 47.3 cm, and friction demonstrated explosion probability of 64%. Compared with raw HMX, cocrystals displayed significantly reduced mechanical sensitivity. Chongwei An, Hequn Li, Baoyun Ye, and Jingyu Wang Copyright © 2017 Chongwei An et al. All rights reserved. Properties of Polystyrene Clay Nanocomposites Prepared Using Two New Imidazolium Surfactants Thu, 26 Jan 2017 08:12:53 +0000 Montmorillonite/polystyrene nanocomposites were prepared by in situ photopolymerization of styrene in the presence of 2% by weight of clay organomodified by two new imidazolium surfactants having in their structure an alkyl chain with 20 or 22 carbon atoms, respectively. Thermogravimetry showed that the new surfactants are more thermally stable than conventional alkylammonium surfactants. The properties of the obtained nanocomposites were compared with those of pristine polystyrene, with those of a microcomposite obtained by in situ polymerization of styrene in the presence of unmodified clay, and with those of a nanocomposite obtained starting from an organomodified clay with a short alkyl chain (12 carbon atoms) imidazolium surfactant. XRD, TEM, and rheological analysis showed that the clay/PS nanocomposites have a mixture of intercalated and partially exfoliated structure layers, where the higher the surfactant alkyl chain length, the higher the exfoliation degree. Kinetics curve of accelerated UV aging, obtained by following through infrared spectroscopy the increase of carbonyl functions during aging, showed that the rate of photooxidation of clay containing samples is higher than neat polystyrene. The rate is higher as a function of the degree of dispersion of the filler in the polymer matrix. Giovanna Di Pasquale and Antonino Pollicino Copyright © 2017 Giovanna Di Pasquale and Antonino Pollicino. All rights reserved. Heat Dissipation of Resonant Absorption in Metal Nanoparticle-Polymer Films Described at Particle Separation Near Resonant Wavelength Thu, 26 Jan 2017 00:00:00 +0000 Polymer films containing plasmonic nanostructures are of increasing interest for development of responsive energy, sensing, and therapeutic systems. The present work evaluates heat dissipated from power absorbed by resonant gold (Au) nanoparticles (NP) with negligible Rayleigh scattering cross sections randomly dispersed in polydimethylsiloxane (PDMS) films. Finite element analysis (FEA) of heat transport was coordinated with characterization of resonant absorption by Mie theory and coupled dipole approximation (CDA). At AuNP particle separation greater than resonant wavelength, correspondence was observed between measured and CDA-predicted optical absorption and FEA-derived power dissipation. At AuNP particle separation less than resonant wavelength, measured extinction increased relative to predicted values, while FEA-derived power dissipation remained comparable to CDA-predicted power absorption before lagging observed extinguished power at higher AuNP content and resulting particle separation. Effects of isolated particles, for example, scattering, and particle-particle interactions, for example, multiple scattering, aggregation on observed optothermal activity were evaluated. These complementary approaches to distinguish contributions to resonant heat dissipation from isolated particle absorption and interparticle interactions support design and adaptive control of thermoplasmonic materials for a variety of implementations. Jeremy R. Dunklin and D. Keith Roper Copyright © 2017 Jeremy R. Dunklin and D. Keith Roper. All rights reserved.