Journal of Nanomaterials The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Catalytic Hydrodechlorination of Trichlorobenzenes with Pd(Phen)Cl2 as Catalyst Precursor Thu, 27 Aug 2015 15:48:58 +0000 We reported the catalytic hydrodechlorination (HDC) of trichlorobenzenes by an organometallic compound Pd(Phen)Cl2 as a catalyst precursor. The catalyst precursor was prepared by chemical coordination reaction and characterized by FTIR and 1H NMR techniques. The HDC performance of Pd(Phen)Cl2 as catalyst precursor was evaluated on 1,2,3-, 1,2,4-, and 1,3,5-trichlorobenzenes (TCBs). All TCBs could be converted to dechlorination products with high conversion. Products distribution was closely related with the substrate structures and C-Cl bond energies. A reasonable reaction mechanism was also proposed. Guanlin Zhang, Hu Xu, Yuehui Fan, Yuhong Wang, Lirong Zhang, and Guanzhong Lu Copyright © 2015 Guanlin Zhang et al. All rights reserved. Evolution of InAs/GaAs QDs Size with the Growth Rate: A Numerical Investigation Thu, 27 Aug 2015 15:19:45 +0000 This paper investigates the impact of the deposition rate on the mean buried InAs/GaAs quantum dots’ (QDs) size by means of a coupled photoluminescence spectroscopy and numerical approach. The proposed method consists in tuning the theoretical transition energies by changing the QDs aspect ratio towards best fit of the photoluminescence emission energies arising from the state filling effect. The electron-hole confined states are obtained by solving the single particle one band effective mass Schrödinger equation in cylindrical coordinates for a lens shaped QD by finite element method taking into account the strain effects. The obtained evolution is in agreement with morphological data taken from similar uncapped QDs samples. Bouraoui Ilahi, Manel Souaf, Mourad Baira, Jawaher Alrashdi, Larbi Sfaxi, Abdulaziz Alhazaa, and Hassen Maaref Copyright © 2015 Bouraoui Ilahi et al. All rights reserved. Improvement in Tracing Quantum Dot-Conjugated Nanospheres for In Vivo Imaging by Eliminating Food Autofluorescence Thu, 27 Aug 2015 13:39:42 +0000 Fluorescence imaging using fluorescent probes has demonstrated long-term stability and brightness suitable for in vivo deep-tissue imaging, but it also allows intense background fluorescence associated with food in the near-infrared (IR) range. We investigated effects of changing rodent diet on food autofluorescence, in the presence of quantum dots-conjugated magnetic nanospheres (QD-MNSs). Replacement of a regular rodent diet with a purified diet has great improvement in removing autofluorescence in the near-infrared range ideal for in vivo fluorescence imaging. By feeding a purified diet for eliminating ingredients impairing desirable fluorescence signals in the near-IR range, food autofluorescence was clearly eliminated and fluorescence probes, QD-MNSs, introduced by i.v. injection were effectively traced in a mouse by a distinctive signal-to-noise ratio. Chul-Kyu Park and Hoonsung Cho Copyright © 2015 Chul-Kyu Park and Hoonsung Cho. All rights reserved. High Luminescence White LEDs Prepared with 2D Island-Pattern of Quantum Dots Dispersed Photopolymer Films Thu, 27 Aug 2015 12:26:38 +0000 Since the reabsorption loss among different size quantum dots (QDs) is a critical issue in the QD based white LEDs, we proposed and fabricated new film structure of 2D island-patterns consisting of separate green and red QDs dispersed photopolymer patterns in a zigzag form. A small air-gap such as 60 μm between QD islands helps to control the optical path at the interface to reduce the lateral reabsorption loss to enhance the optical efficiency of white LED. The 2D island-patterns of QD phosphor film were fabricated using a UV imprinting process and compared the optical efficiency with the other QD film structure prepared with same QD concentrations and thicknesses such as a mixed and separately layered QD structure. Experimental and simulation analysis were performed to confirm the better optical efficiency from the 2D island-patterns of QD films due to the reduced reabsorption loss. High luminescence white LED was finally realized with 2D island-patterns of QD film, resulting in a luminous efficiency of 62.2 lm/W and CRI of 83 with CCT of 4537 K at the operation current of 60 mA. Hyun-Guk Hong, Min-Ho Shin, Hyo-Jun Kim, Jinsoo Shin, and Young-Joo Kim Copyright © 2015 Hyun-Guk Hong et al. All rights reserved. Synthesis of High Crystalline Al-Doped ZnO Nanopowders from Al2O3 and ZnO by Radio-Frequency Thermal Plasma Thu, 27 Aug 2015 12:17:59 +0000 High crystalline Al-doped ZnO (AZO) nanopowders were prepared by in-flight treatment of ZnO and Al2O3 in Radio-Frequency (RF) thermal plasma. Micron-sized (~1 μm) ZnO and Al2O3 powders were mixed at Al/Zn ratios of 3.3 and 6.7 at.% and then injected into the RF thermal plasma torch along the centerline at a feeding rate of 6.6 g/min. The RF thermal plasma torch system was operated at the plate power level of ~140 kVA to evaporate the mixture oxides and the resultant vapor species were condensed into solid particles by the high flow rate of quenching gas (~7000 slpm). The FE-SEM images of the as-treated powders showed that the multipod shaped and the whisker type nanoparticles were mainly synthesized. In addition, these nanocrystalline structures were confirmed as the single phase AZO nanopowders with the hexagonal wurtzite ZnO structure by the XRD patterns and FE-TEM results with the SAED image. However, the composition changes of 0.3 and 1.0 at.% were checked for the as-synthesized AZO nanopowders at Al/Zn ratios of 3.3 and 6.7 at.%, respectively, by the XRF data, which can require the adjustment of Al/Zn in the mixture precursors for the applications of high Al doping concentrations. Min-Kyeong Song, Mi-Yeon Lee, Jun-Ho Seo, Min-Ho Kim, and Shi-Young Yang Copyright © 2015 Min-Kyeong Song et al. All rights reserved. Direct Determination of Spatial Localization of Carriers in CdSe-CdS Quantum Dots Thu, 27 Aug 2015 12:09:20 +0000 Colloidal quantum dots (QDs) have gained significant attention due to their tunable band gap, simple solution processability, ease of scale-up, and low cost. By carefully choosing the materials, core-shell heterostructure QDs (HQDs) can be further synthesized with a controlled spatial spread of wave functions of the excited electrons and holes for various applications. Many investigations have been done to understand the exciton dynamics by optical characterizations. However, these spectroscopic data demonstrate that the spatial separation of the excitons cannot distinguish the distribution of excited electrons and holes. In this work, we report a simple and direct method to determine the localized holes and delocalized electrons in HQDs. The quasi-type-II CdSe-CdS core-shell QDs were synthesized via a thermolysis method. Poly(3-hexylthiophene) (P3HT) nanofiber and ZnO nanorods were selected as hole and electron conductor materials, respectively, and were combined with HQDs to form two different nanocomposites. Photoelectrical properties were evaluated under different environments via a quick and facile characterization method, confirming that the electrons in the HQDs were freely accessible at the surface of the nanocrystal, while the holes were confined within the CdSe core. Yichen Zhao, Abhilash Sugunan, Qin Wang, Xuran Yang, David B. Rihtnesberg, and Muhammet S. Toprak Copyright © 2015 Yichen Zhao et al. All rights reserved. Core-Shell Structure of Gold Nanoparticles with Inositol Hexaphosphate Nanohybrids for Label-Free and Rapid Detection by SERS Nanotechnology Thu, 27 Aug 2015 11:49:50 +0000 Gold nanoparticles bound with inositol hexaphosphate (IP6) (AuNPs/IP6) were prepared by in situ reduction of various concentrations of IP6 (0~320 µM) through modified Frens method for surface-enhanced Raman scattering (SERS) detection. The resultant AuNPs/IP6 were subject to characterization including UV/Vis spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential, and X-ray photoelectron spectroscopy (XPS). The results showed that AuNPs with 65 µM of IP6 would result in a core AuNPs-shell (IP6 layer) structure, which exhibited the strongest SERS signal, due to the “hot spot effect” generated from the 1-2 nm interparticle gaps of AuNPs/IP6 nanohybrids (ionic interaction of IP6 and Au+). Furthermore, the reaction kinetics of Au and IP6 were also investigated in this work. Higher concentration of IP6 (190 and 260 µM) will make AuNPs become irregularly shaped, because IP6 is a basic salt and served as a pH mediator. The morphology and distribution of AuNPs were greatly improved by addition of 65 µM of IP6. This novel AuNPs/IP6 nanohybrid showed great stability and Raman enhancement. It is promising in the application of rapid and label-free biological detection of bacteria or tumor cells. Andreas H. H. Mevold, Jin-Yuan Liu, Li-Ying Huang, Hung-Liang Liao, Ming-Chien Yang, Tzu-Yi Chan, Kuan-Syun Wang, Juen-Kai Wang, Yuh-Lin Wang, and Ting-Yu Liu Copyright © 2015 Andreas H. H. Mevold et al. All rights reserved. The Core/Shell Structure of CdSe/ZnS Quantum Dots Characterized by X-Ray Absorption Fine Spectroscopy Thu, 27 Aug 2015 11:43:45 +0000 Understanding the chemical and physical properties of core/shell nanocrystal quantum dots (QDs) is key for their use in light-emission applications. In this paper, a single-step injection-free scalable synthetic method is applied to prepare high-quality core/shell QDs with emission wavelengths of 544 nm, 601 nm, and 634 nm. X-ray absorption fine structure spectra are used to determine the core/shell structure of CdSe/ZnS quantum dots. Moreover, theoretical XANES spectra calculated by FEFF.8.20 are used to determine the structure of Se and S compounds. The QD samples displayed nearly spherical shapes with diameters of approximately 3.4 ± 0.5 nm (634 nm), 4.5 ± 0.4 nm (601 nm), and 5.5 ± 0.5 nm (544 nm). With XANES results and MS calculations, it is indicated that sphalerite ZnS capped with organic sulfur ligands should be the shell structure. Wurtzite CdSe is the main core structure with a Cd-Se bond length of 2.3 Å without phase shift. This means that different emission wavelengths are only due to the crystal size with single-step injection-free synthesis. Therefore, single-step injection-free synthesis could generate a nearly ideal core/shell structure of CdSe/ZnS QDs capped with an organic sulfur ligand. Huijing Wei, Jing Zhou, Linjuan Zhang, Fang Wang, Jianqiang Wang, and Chan Jin Copyright © 2015 Huijing Wei et al. All rights reserved. Catalyst Nanomaterials Thu, 27 Aug 2015 08:27:33 +0000 Ping Xu, Bo Song, Hongmei Luo, Ling Fei, and Hsing-Lin Wang Copyright © 2015 Ping Xu et al. All rights reserved. Preparation of Mesoporous Silica-Supported Chiral Amino Alcohols for the Enantioselective Addition of Diethylzinc to Aldehyde and Asymmetric Transfer Hydrogenation to Ketones Wed, 26 Aug 2015 12:02:42 +0000 Optically active (−)-ephedrine, (−)-norephedrine, and (−)-prolinol were immobilized onto cubic mesoporous MCM-48 silica. The immobilized amino alcohols served as a heterogeneous chiral catalyst for the asymmetric addition of diethylzinc to aldehydes and transfer hydrogenation to ketones. The developed catalytic process yielded optically enriches secondary aromatic alcohols with 92–99% conversion and 70–82% enantioselectivity. Shaheen M. Sarkar, Md. Eaqub Ali, Md. Lutfor Rahman, and Mashitah Mohd Yusoff Copyright © 2015 Shaheen M. Sarkar et al. All rights reserved. Silver Nanoparticles Influence on Photocatalytic Activity of Hybrid Materials Based on TiO2 P25 Wed, 26 Aug 2015 11:45:26 +0000 The aim of the present study consists in the obtaining of a hybrid material film, obtained using TiO2 P25 and silver nanoparticles (AgNPs). The film manufacturing process involved realization of physical mixtures of TiO2 P25 and AgNPs dispersions. The size distribution of the AgNPs proved to be a key factor determining the photodegradation activity of the materials measured using methyl orange. The best result was 33% degradation of methyl orange (MO) after 150 min. The second approach was the generation of AgNPs on the surface of TiO2 P25. The obtained hybrid material presents photocatalytic activity of 45% MO degradation after 150 min. The developed materials were characterized by UV-VIS, SEM, and DLS analyses. Tomkouani Kodom, Edina Rusen, Ioan Călinescu, Alexandra Mocanu, Raluca Şomoghi, Adrian Dinescu, Aurel Diacon, and Cristian Boscornea Copyright © 2015 Tomkouani Kodom et al. All rights reserved. Direct Synthesis of Porous Multilayer Graphene Materials Using Thermal Plasma at Low Pressure Wed, 26 Aug 2015 07:02:40 +0000 Porous multilayer graphenes have been synthesized by decomposition of hydrocarbons in a thermal plasma jet. Products of synthesis were characterized by electron microscopy, thermogravimetry, Raman spectroscopy, and X-ray diffraction. Possibility of producing a wide range of graphene materials with different morphology and structure has been shown. Influence of the experimental conditions on mesopores structure of the synthesis products has been investigated using the method of “limited evaporation.” Ravil Amirov, Marina Shavelkina, Nariman Alihanov, Evgeny Shkolnikov, Alexander Tyuftyaev, and Natalya Vorob’eva Copyright © 2015 Ravil Amirov et al. All rights reserved. A Platinum Monolayer Core-Shell Catalyst with a Ternary Alloy Nanoparticle Core and Enhanced Stability for the Oxygen Reduction Reaction Tue, 25 Aug 2015 14:20:00 +0000 We synthesize a platinum monolayer core-shell catalyst with a ternary alloy nanoparticle core of Pd, Ir, and Ni. A Pt monolayer is deposited on carbon-supported PdIrNi nanoparticles using an underpotential deposition method, in which a copper monolayer is applied to the ternary nanoparticles; this is followed by the galvanic displacement of Cu with Pt to generate a Pt monolayer on the surface of the core. The core-shell Pd1Ir1Ni2@Pt/C catalyst exhibits excellent oxygen reduction reaction activity, yielding a mass activity significantly higher than that of Pt monolayer catalysts containing PdIr or PdNi nanoparticles as cores and four times higher than that of a commercial Pt/C electrocatalyst. In 0.1 M HClO4, the half-wave potential reaches 0.91 V, about 30 mV higher than that of Pt/C. We verify the structure and composition of the carbon-supported PdIrNi nanoparticles using X-ray powder diffraction, X-ray photoelectron spectroscopy, thermogravimetry, transmission electron microscopy, and energy dispersive X-ray spectrometry, and we perform a stability test that confirms the excellent stability of our core-shell catalyst. We suggest that the porous structure resulting from the dissolution of Ni in the alloy nanoparticles may be the main reason for the catalyst’s enhanced performance. Haoxiong Nan, Xinlong Tian, Lijun Yang, Ting Shu, Huiyu Song, and Shijun Liao Copyright © 2015 Haoxiong Nan et al. All rights reserved. Synthesis of Hydrocarbons from H2-Deficient Syngas in Fischer-Tropsch Synthesis over Co-Based Catalyst Coupled with Fe-Based Catalyst as Water-Gas Shift Reaction Tue, 25 Aug 2015 14:17:52 +0000 The effects of metal species in an Fe-based catalyst on structural properties were investigated through the synthesis of Fe-based catalysts containing various metal species such, as Mn, Zr, and Ce. The addition of the metal species to the Fe-based catalyst resulted in high dispersions of the Fe species and high surface areas due to the formation of mesoporous voids about 2–4 nm surrounded by the catalyst particles. The metal-added Fe-based catalysts were employed together with Co-loaded beta zeolite for the synthesis of hydrocarbons from syngas with a lower H2/CO ratio of 1 than the stoichiometric H2/CO ratio of 2 for the Fischer-Tropsch synthesis (FTS). Among the catalysts, the Mn-added Fe-based catalyst exhibited a high activity for the water-gas shift (WGS) reaction with a comparative durability, leading to the enhancement of the CO hydrogenation in the FTS in comparison with Co-loaded beta zeolite alone. Furthermore, the loading of Pd on the Mn-added Fe-based catalyst enhanced the catalytic durability due to the hydrogenation of carbonaceous species by the hydrogen activated over Pd. Ting Ma, Hiroyuki Imai, Tomohiro Shige, Taisuke Sugio, and Xiaohong Li Copyright © 2015 Ting Ma et al. All rights reserved. Fe3+-Exchanged Titanate Nanotubes: A New Kind of Highly Active Heterogeneous Catalyst for Friedel-Crafts Type Benzylation Tue, 25 Aug 2015 13:26:40 +0000 Heterogeneous catalysis for Friedel-Crafts type benzylation has received much attention in recent years due to its characteristic of environmental benefits. In this paper, titanate nanotubes (TNTs) were employed as heterogeneous catalyst support, and a new kind of Fe3+-exchanged titanate nanotubes (Fe-TNTs) catalyst with highly dispersed ferric sites was constructed by an ion exchange technique. The obtained catalyst was systematically characterized by XRD, TEM, N2 adsorption, XPS, and UV-vis spectra. As expected, Fe-TNTs showed excellent catalytic activities in the benzylation of benzene and benzene derivatives. The recycling tests for Fe-TNTs were also carried out, where the reason for the gradually decreased activity was carefully investigated. Superior to some reported catalysts, the catalytic ability of used Fe-TNTs could be easily recovered by ion exchange again, indicating that Fe-TNTs herein were a highly active and durable heterogeneous catalyst for Friedel-Crafts type benzylation. These results might be helpful for the design and preparation of novel heterogeneous catalysts by combining the structural advantages of titanate nanotubes and active metal ions. Yunchen Du, Di Guo, Meiling Xiong, Yanwu Qi, Chenkui Cui, Jun Ma, Xijiang Han, and Ping Xu Copyright © 2015 Yunchen Du et al. All rights reserved. Comment on “Improving Light Outcoupling Efficiency for OLEDs with Microlens Array Fabricated on Transparent Substrate” Sun, 23 Aug 2015 10:45:34 +0000 Joondong Kim Copyright © 2015 Joondong Kim. All rights reserved. Structural, Thermal, Optical, Electrical, and Adhesive Characteristics of FePdB Thin Films Sun, 23 Aug 2015 08:09:51 +0000 To study the structural, thermal, electrical, optical, and adhesive properties of magnetic FePdB thin films, 25–200-Å-thick Fe40Pd40B20 and Fe60Pd20B20 films were deposited on a glass substrate by direct current (DC) magnetron sputtering at room temperature (RT). X-ray diffraction (XRD) patterns indicated that the 25–75-Å-thick Fe40Pd40B20 and Fe60Pd20B20 films were amorphous, whereas the 100–200-Å-thick Fe40Pd40B20 and Fe60Pd20B20 films were crystalline, with a face-centered cubic (FCC) FePd (111) textured structure. The activation energy of the Fe40Pd40B20 and Fe60Pd20B20 thin films decreased as thickness was increased. The 25-Å-thick Fe40Pd40B20 film exhibited the highest resistivity, whereas the 200-Å-thick Fe60Pd20B20 film exhibited the lowest resistivity. Increasing the thickness and crystallization reduced transmission. The Fe40Pd40B20 thin films exhibited higher surface energy and stronger adhesion than did Fe60Pd20B20 thin films. Yuan-Tsung Chen Copyright © 2015 Yuan-Tsung Chen. All rights reserved. Effects of Adding Multiwall Carbon Nanotubes on Performance of Polyvinyl Acetate and Urea-Formaldehyde Adhesives in Tropical Timber Species Thu, 20 Aug 2015 09:34:34 +0000 Multiwall carbon nanotubes (MWCNTs) functionalized with hydroxyl groups (MWCNTs-OH) have been incorporated into polyvinyl acetate (PVAc) and urea-formaldehyde (UF) adhesives utilized in tropical wood gluing. The Raman spectroscopy, the atomic force microscopy (AFM), and transmission electron microscopy (TEM) were used to describe the MWCNTs-OH. The adhesives were evaluated in three concentrations of MWCNTs-OH: 0% (control), 0.05%, and 0.1%. The evaluation included color, the distribution of MWCNTs-OH by TEM and AFM, thermal stability and viscosity of the adhesives, and shear strength (SS) of the glue line for nine tropical woods. AFM and TEM confirmed interaction of MWCNTs-OH with adhesives. The viscosity of the PVAc adhesive increases with added MWCNTs-OH. The incorporation of MWCNTs-OH in PVAc and UF resin produces wood adhesives with less brightness, less yellowness, and increased redness. The nanotubes in the adhesive improved the thermal stability of the composites and increased the entropy factor and energy of activation in the kinetic decomposition of the resin. In relation to SS, MWCNTs-OH in any of the two concentrations had no significant effect on SS in dry condition in half of the species studied glued with PVAc adhesive, whereas, for UF-adhesive, the SS and percentage of wood failure improved in most of the 9 species studied. Róger Moya, Ana Rodríguez-Zúñiga, and José Vega-Baudrit Copyright © 2015 Róger Moya et al. All rights reserved. Iterative Cellular Screening System for Nanoparticle Safety Testing Wed, 19 Aug 2015 06:19:21 +0000 Nanoparticles have the potential to exhibit risks to human beings and to the environment; due to the wide applications of nanoproducts, extensive risk management must not be neglected. Therefore, we have constructed a cell-based, iterative screening system to examine a variety of nanoproducts concerning their toxicity during development. The sensitivity and application of various cell-based methods were discussed and proven by applying the screening to two different nanoparticles: zinc oxide and titanium dioxide nanoparticles. They were used as benchmarks to set up our methods and to examine their effects on mammalian cell lines. Different biological processes such as cell viability, gene expression of interleukin-8 and heat shock protein 70, as well as morphology changes were investigated. Within our screening system, both nanoparticle suspensions and coatings can be tested. Electric cell impedance measurements revealed to be a good method for online monitoring of cellular behavior. The implementation of three-dimensional cell culture is essential to better mimic in vivo conditions. In conclusion, our screening system is highly efficient, cost minimizing, and reduces the need for animal studies. Franziska Sambale, Frank Stahl, Ferdinand Rüdinger, Dror Seliktar, Cornelia Kasper, Detlef Bahnemann, and Thomas Scheper Copyright © 2015 Franziska Sambale et al. All rights reserved. Preparation and Characterization of Natural Zeolite Modified with Iron Nanoparticles Tue, 18 Aug 2015 16:12:20 +0000 This study is aimed at investigating the structural and morphological characterization of natural and modified zeolite obtained from the state of Oaxaca (Mexico). Iron nanoparticles were used for the zeolite modification. The iron nanoparticles were loaded on the zeolite surface by homogeneous nucleation. Adsorption kinetic models of pseudo first and second order were surveyed. The characterization of pristine and modified zeolite was performed by Fourier transform infrared (FTIR), transmission electron microscopy (TEM), and X-ray diffraction (XRD). From the results, three main phases were identified: clinoptilolite, mordenite, and feldspar. We could also determine the adsorption capacity of the zeolites by means of adsorption kinetic models. Alvaro Ruíz-Baltazar, Rodrigo Esparza, Maykel Gonzalez, Gerardo Rosas, and Ramiro Pérez Copyright © 2015 Alvaro Ruíz-Baltazar et al. All rights reserved. Fabrication and Characterization of CNT-Based Smart Tips for Synchrotron Assisted STM Tue, 18 Aug 2015 12:56:08 +0000 Determination of chemical composition along with imaging at the atomic level provides critical information towards fundamental understanding of the surface of materials and, hence, yields the capability to design new materials by tailoring their ultimate functionalities. Synchrotron X-ray assisted scanning tunneling microscopy (SX-STM) is a promising new technique to achieve real space chemically specific atomic mapping. Chemical sensitivity of SX-STM relies on excitation of core electrons by incident X-rays when their energy is tuned to an absorption edge of a particular element. However, along with core-level electrons, photoelectrons are also excited, which yield additional current and interfere with the tunneling current. To reduce the background photoelectron current and to improve ultimate resolution of SX-STM, we have developed and fabricated multiwalled carbon nanotubes (MWCNT) based “smart tips” using plasma enhanced chemical vapor deposition and focused ion beam milling. The newly developed CNT-based smart tips, characterized step by step by scanning electron microscopy (SEM) during the fabrication process, demonstrate good performance and provide opportunity for realizing atomic chemical mapping. Hui Yan, Marvin Cummings, Fernando Camino, Weihe Xu, Ming Lu, Xiao Tong, Nozomi Shirato, Daniel Rosenmann, Volker Rose, and Evgeny Nazaretski Copyright © 2015 Hui Yan et al. All rights reserved. Computation of Topological Indices of Graphene Tue, 18 Aug 2015 08:52:54 +0000 We compute ABC index, ABC4 index, Randic connectivity index, Sum connectivity index, GA index, and GA5 index of Graphene. G. Sridhara, M. R. Rajesh Kanna, and R. S. Indumathi Copyright © 2015 G. Sridhara et al. All rights reserved. Spacer Thickness-Dependent Electron Transport Performance of Titanium Dioxide Thick Film for Dye-Sensitized Solar Cells Tue, 18 Aug 2015 08:20:15 +0000 A titanium dioxide (P25) film was deposited by cast coating as conductive photoelectrode and subsequently immersed in dye solution (N719) to fabricate the photoanode of dye-sensitized solar cells (DSSCs). A plastic spacer was used as a separation and sealant layer between the photoanode and the counter electrode. The effect of the thickness of this spacer on the transfer of electrons in the liquid electrolyte of the DSSCs was studied by means of both IV curves and electrochemical impedance. Using a spacer thickness range of 20 μm to 50 μm, efficiency ranges from 3.73% to 7.22%. The highest efficiency of 7.22% was obtained with an optimal spacer thickness of 40 μm. Reda E. El-Shater, Mohamed M. Abdel-Galeil, Go Kawamura, and Atsunori Matsuda Copyright © 2015 Reda E. El-Shater et al. All rights reserved. Cyclic Strain Enhances Cellular Uptake of Nanoparticles Mon, 17 Aug 2015 11:55:00 +0000 Nanoparticles (NPs) have gained increasing interest in recent years due to their potential use as drug carrier, imaging, and diagnostic agents in pharmaceutical and biomedical applications. While many cells in vivo experience mechanical forces, little is known about the correlation of the mechanical stimulation and the internalization of NPs into cells. This paper investigates the effects of applied cyclic strain on NP uptake by cells. Bovine aortic endothelial cells (BAECs) were cultured on collagen-coated culture plates and placed under cyclic equal-axial strains. NPs of sizes ranging from 50 to 200 nm were loaded at a concentration of 0.02 mg/mL and cyclic strains from 5 to 15% were applied to the cells for one hour. The cyclic strain results in a significant enhancement in NP uptake, which increases almost linearly with strain level. The enhanced uptake also depends on size of the NPs with the highest uptake observed on 100 nm NP. The effect of enhanced NP uptake lasts around 13 hours after cyclic stretch. Such in vitro cell stretch systems mimic physiological conditions of the endothelial cells in vivo and could potentially serve as a biomimetic platform for drug therapeutic evaluation. Jia Hu and Yaling Liu Copyright © 2015 Jia Hu and Yaling Liu. All rights reserved. Formation of - Eutectic EBC Film on Silicon Carbide Substrate Mon, 17 Aug 2015 11:34:21 +0000 The formation mechanism of - eutectic structure, the preparation method, and the formation mechanism of the eutectic EBC layer on the silicon carbide substrate are summarized. - eutectic EBC film is prepared by optical zone melting method on the silicon carbide substrate. At high temperature, a small amount of silicon carbide decomposed into silicon and carbon. The components of and in molten phase also react with the free carbon. The phase reacts with free carbon and vapor species of AlO phase is formed. The composition of the molten phase becomes rich from the eutectic composition. phase also reacts with the free carbon and HfC phase is formed on the silicon carbide substrate; then a high density intermediate layer is formed. The adhesion between the intermediate layer and the substrate is excellent by an anchor effect. When the solidification process finished before all of phase is reduced to HfC phase, HfC- functionally graded layer is formed on the silicon carbide substrate and the - eutectic structure grows from the top of the intermediate layer. Kyosuke Seya, Shunkichi Ueno, and Byung-Koog Jang Copyright © 2015 Kyosuke Seya et al. All rights reserved. Preparation of Nanostructured Microporous Metal Foams through Flow Induced Electroless Deposition Mon, 17 Aug 2015 08:45:24 +0000 Monolithic nanostructured metallic porous structures with a hierarchy of pore size ranging from ca. 10 μm to 1 nm are processed for use as microreactors. The technique is based on flow induced electroless deposition of metals on a porous template known as PolyHIPE Polymer. The process is conducted in a purpose built flow reactor using a processing protocol to allow uniform and efficient metal deposition under flow. Nickel chloride and sodium hypophosphite were used as the metal and reducing agent, respectively. Electroless deposition occurs in the form of grains with a composition of in which the grain size range was ca. 20–0.2 μm depending on the composition of the metal deposition solution. Structure formation in the monoliths starts with heat treatment above 600°C resulting in the formation of a 3-dimensional network of capillary-like porous structures which form the walls of large arterial pores. These monoliths have a dense but porous surface providing mechanical strength for the monolith. The porous capillary-like arterial pore walls provide a large surface area for any catalytic activity. The mechanisms of metal deposition and nanostructure formation are evaluated using scanning electron microscopy, energy dispersive X-ray analysis, XRD, BET-surface area, and mercury intrusion porosimetry. Galip Akay and Burak Calkan Copyright © 2015 Galip Akay and Burak Calkan. All rights reserved. Cisplatin Loaded Hyaluronic Acid Modified TiO2 Nanoparticles for Neoadjuvant Chemotherapy of Ovarian Cancer Mon, 17 Aug 2015 08:26:32 +0000 Novel tumor-targeting titanium dioxide () nanoparticles modified with hyaluronic acid (HA) were developed to explore the feasibility of exploiting the pH-responsive drug release property of and the tumor-targeting ability of HA to construct a tumor-targeting cisplatin (CDDP) delivery system (HA-) for potential neoadjuvant chemotherapy of ovarian cancer. The experimental results indicated that CDDP release from the HA- nanoparticles was significantly accelerated by decreasing pH from 7.4 to 5.0, which is of particular benefit to cancer therapy. CDDP-loaded HA- nanoparticles increased the accumulation of CDDP in A2780 ovarian cancer cells via HA-mediated endocytosis and exhibited superior anticancer activity in vitro. In vivo real-time imaging assay revealed that HA- nanoparticles possessed preferable tumor-targeting ability which might potentially minimize the toxic side effects of CDDP in clinical application. Enling Liu, Yuxiu Zhou, Zheng Liu, Jun Li, Donghong Zhang, Junchen Chen, and Zhaohui Cai Copyright © 2015 Enling Liu et al. All rights reserved. Comparison of Three Molecular Simulation Approaches for Cyclodextrin-Ibuprofen Complexation Sun, 16 Aug 2015 07:05:02 +0000 Cyclodextrins are widely used for the solubilisation of poorly soluble drugs in the formulations. However, current cyclodextrin formulation development strongly depends on trial-and-error in the laboratory, which is time-consuming and high cost. The aim of this research was to compare three modeling approaches (Docking, molecular dynamics (MD), and quantum mechanics (QM)) for cyclodextrin/drug complexation. Ibuprofen was used as a model drug. Binding free energy from three simulation methods was calculated as an important parameter to compare with the experimental results. Docking results from AutoDock Vina program showed that the scoring of complexation capability between ibuprofen and cyclodextrins is alpha (α), gamma (γ), beta (β), and HP-beta-cyclodextrins, which indicated similar ranking with the results from phase, solubility diagram experiments. MD simulation indicated that ibuprofen could form the stable complexes with β-, γ-, and HP-β-cyclodextrins, but not for alpha cyclodextrin. Binding free energies from the MD simulation for β-, γ-, and HP-β-cyclodextrins were −3.67, −0.67, and −3.87 kcal/mol, individually. The enthalpies of QM simulation for β-, γ-, and HP-β-cyclodextrins were −17.22, −14.75, and −20.28 kcal/mol, respectively. Results from all three modeling approaches showed similar ranking between ibuprofen and four cyclodextrin molecules as the experimental data. However, MD simulation with entropy calculation had the closest value to experimental data for β and HP-beta-cyclodextrins. Thus, MD simulation with MM-PBSA method may be fit to in silico screen for cyclodextrin formulations. Runmiao Wang, Hui Zhou, Shirley W. I. Siu, Yong Gan, Yitao Wang, and Defang Ouyang Copyright © 2015 Runmiao Wang et al. All rights reserved. The Gelation Ability and Morphology Study of Organogel System Based on Calamitic Hydrazide Derivatives Thu, 13 Aug 2015 14:27:08 +0000 The gelation property of a series of LMOG bearing hydrazide and azobenzene groups, namely, N-4-(alkoxyphenyl)-N′-4-[(4-methoxyphenyl)azophenyl] benzohydrazide (BNBC-, ), has been systematically studied in this work. The obtained results demonstrate that the gelling ability in organic solvents is significantly influenced by the length of terminal alkoxy chain. In different organic solvents, it is hard to observe the organogel formation for BNBC-8 molecule. On the contrary, the organogelators BNBC-12 and BNBC-14 bearing longer terminal chains have shown great ability to gel organic solvents to form stable organogels. The critical gelation concentration for BNBC-12 reaches as low as 5.3 × 10−3 M, which can be considered as a supergelator. It has been manifested that the aggregation morphology of organogel strongly depends on the nature of the gelling solvents and the length of the terminal alkoxy chain. The gelation of BNBC- provides an easy method for the preparation of multidimensional structure and manipulation of morphology from ribbons, hollow tube fiber to 3D net-like structure in different solvents. The cooperation of hydrogen bonding, interaction, and Van der Waals force is suggested to be the main contribution to this self-assembled structure. Xia Ran, Lili Shi, Kun Zhang, Jie Lou, Bo Liu, and Lijun Guo Copyright © 2015 Xia Ran et al. All rights reserved. Preparation of Homogeneous Nanostructures in 5 Minutes for Cancer Cells Capture Thu, 13 Aug 2015 13:28:32 +0000 Grafting aptamers on nanostructured substrates has shown ultrasensitivity in isolation of circulating tumor cells (CTCs). Here, we report that over 80 cm2 of homogenous nanostructured surface on glass substrates can be prepared in 5 min after one-step dry etching. The surface area was doubled; the average diameter of nanostructures is approximately 374 nm, which is more close to the nanostructures of natural extracellular matrix. Antiepithelial cell adhesion molecule aptamers grafted nanostructured glass substrates captured over 76% of PC3 cells compared to 30% of planar substrates. Bispecific aptamers cofunctionalized nanostructured substrates, however, fail to capture cancer cells probably due to the formation of heterodimers. This limitation reveals that multispecific aptamers, when applied to cell isolation, must be analyzed to exclude any potential formation of heterodimers due to complementary sequence matching. Lixue Wang, Chuandong Zhu, Qin Zheng, and Xia He Copyright © 2015 Lixue Wang et al. All rights reserved.