Journal of Nanomaterials The latest articles from Hindawi © 2019 , Hindawi Limited . All rights reserved. An NMR Metabolomics Approach and Detection of Ganoderma boninense-Infected Oil Palm Leaves Using MWCNT-Based Electrochemical Sensor Wed, 19 Jun 2019 09:05:24 +0000 Ganoderma boninense (G. boninense) has been identified as a major problem in oil palm industry which caused basal stem rot disease. Identification of metabolite variation of healthy and G. boninense-infected oil palm leaves at 14 days postinfection using NMR metabolomics approach followed by characterization of an electrochemical sensor based on a functionalized multiwalled carbon nanotube (MWCNT) layer-by-layer framework on modified screen-printed carbon electrode has been successfully determined. Significant differences from the 1H NMR data were observed between healthy and G. boninense-infected oil palm leaves, according to principal component analysis. Gold nanoparticle-functionalized MWCNT and chitosan-functionalized MWCNT were deposited on a screen-printed carbon electrode and were applied for the electrochemical detection of healthy and G. boninense-infected oil palm leaves. The electrocatalytic activities of a modified electrode towards oxidation of healthy and G. boninense-infected oil palm leaves at a concentration of 100 mg/L were evaluated using cyclic voltammetry and linear sweep voltammetry. The limits of detection of healthy and G. boninense-infected oil palm leaves were calculated to 0.0765 mg/L and 0.0414 mg/L, respectively. The modified electrode shows a good sensitivity and reproducibility due to the unique characteristics of gold nanoparticles, chitosan, MWCNTs, and synergistic interaction between them. Azizul Isha, Fowotade Sulayman Akanbi, Nor Azah Yusof, Rosiah Osman, Wong Mui-Yun, and Siti Nor Akmar Abdullah Copyright © 2019 Azizul Isha et al. All rights reserved. Nanogold for In Vitro Inhibition of Salmonella Strains Wed, 19 Jun 2019 09:05:22 +0000 The pathogenic strains of Salmonella typhi, paratyphi, and typhimurium are the major cause of typhoid and food poisoning in children and adults in developing countries. According to WHO estimation, 22 million cases of typhoid fever and 200,000 related deaths occur worldwide each year with an additional 6 million cases of paratyphoid fever estimated to occur annually with the highest incidence in children, resulting in a high death rate. The high use of antibiotics has also given rise to drug-resistant strains. Hence, it was of importance to assess the inhibition and quick detection of pathogenic strains of Salmonella. This study aims to investigate the chemically synthesized gold nanoparticles (GNPs) for its antibacterial activity against clinical isolates of S. typhi and S. paratyphi including food sample isolates. The GNPs were characterized using visible color change, UV-Vis spectrophotometry, FTIR, XRD, DLS, FESEM, TEM, and zeta potential. The plasmon peak at 525 nm and 535 nm confirmed the synthesis of gold nanoparticles. The size of the chemically synthesized gold nanoparticles (GNPs) were in the range of 40-60 nm, while FESEM and TEM images revealed that the GNPs were spherical in shape. For antimicrobial activities, five of the Salmonella strains were isolated from fish and egg samples, while the other seven were S. typhi and S. paratyphi from clinical samples. The inhibition factor for GNPs showed higher inhibition against S. paratyphi, while the inhibition factor for S. typhi were found to be higher than Ciprofloxacin-30. This is the first study of the antibacterial efficacy of GNPs against pathogenic strains of Salmonella. The obtained results suggest that nanobioconjugated gold may be of interest in the detection of typhoid and high potential use in areas in biomedicine as an alternative to antibiotics. Mercy Adusei Boatemaa, Ramachandra Ragunathan, and Jishnu Naskar Copyright © 2019 Mercy Adusei Boatemaa et al. All rights reserved. Far-Field Analysis on Reflecting Colors of Dielectric Nanosphere Metasurface Sun, 16 Jun 2019 00:05:41 +0000 Photonic resonances in nanostructures have been exploited in reflective or transmission color filters, which can provide vivid colors. Metallic nanostructures have been widely studied to demonstrate a variety of color filters based on strong light interaction due to plasmonic resonances. However, because of the severe absorption loss of metal in visible light, dielectric nanoparticles having Mie resonances are a popular study focus in recent years to achieve vivid colors. In contrast to the behaviors of point-like electric dipole in metallic nanoparticle, the interplay of the electric and magnetic Mie resonances in dielectric nanoparticle enables a large degree of freedom in manipulating the directivity of light scattering, reflecting/transmitting color, and spontaneous emission rates. Here, we propose a color reflector based on an array of silicon nanoparticles that shows reflectance greater than 70% and vivid colors over the entire visible spectrum range, which covers sRGB color area. Viewing angle dependencies of the color and brightness are also investigated by calculating color-resolved far-field patterns, while exhibiting maintenance of the color and high reflectance over a broad viewing angle. Seokhyeon Hong, Young Jin Lee, Kihwan Moon, Youngsoo Kim, Eunso Shin, and Soon-Hong Kwon Copyright © 2019 Seokhyeon Hong et al. All rights reserved. Molecular Simulations of Adsorption and Thermal Energy Storage of Mixed R1234ze/UIO-66 Nanoparticle Nanofluid Sun, 16 Jun 2019 00:05:39 +0000 In the process of adsorption and separation of fluid molecules on the solid surface of porous nanomaterials, the mutual transformation of thermal energy and surface energy can improve the heat absorption and energy utilization efficiency of circulating working medium. In this study, the adsorption, thermal energy storage, and mean square displacement of the minimum energy adsorption configuration of R1234ze in UIO-66 were studied by molecular simulations, including molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations. The results show that the thermal energy storage density of R1234ze/UIO-66 mixed working medium is significantly higher than that of pure working medium in the temperature range of 20 K-140 K. However, the increase rate of thermal energy storage density decreases significantly as temperature rises, and the mean square displacement and diffusion coefficient increase with increasing temperature. Qiang Wang, Shengli Tang, Sen Tian, Xiaojian Wei, and Tiefeng Peng Copyright © 2019 Qiang Wang et al. All rights reserved. Effect of Size on the Saturable Absorption and Reverse Saturable Absorption in Silver Nanoparticle and Ultrafast Dynamics at 400 nm Thu, 13 Jun 2019 09:05:26 +0000 Saturable absorption and reverse saturable absorption play an important role in the studies of the nonlinear optical properties of nanoparticles at resonant excitation. With this viewpoint, nonlinear absorption processes of chemically prepared silver nanoparticles in deionized water were studied using femtosecond laser pulses at 400 nm. Our nonlinear absorption study shows that there is competition between saturable absorption and two-photon absorption in prepared Ag NPs which depends on the size of the nanoparticles. We have also studied the ultrafast dynamics associated with nanoparticles which also results in the direct correlation between the ultrafast timescale and the size of the nanoparticle. The excitation of Ag NPs at 400 nm has shown the manifestation of damped oscillation which is attributed to the radial breathing mode oscillation due to acoustic vibration. Sandeep Kumar Maurya, Anuradha Rout, Rashid A. Ganeev, and Chunlei Guo Copyright © 2019 Sandeep Kumar Maurya et al. All rights reserved. Physical Absorption of Folic Acid and Chitosan on Dihydroartemisinin-Loaded Poly-Lactic-Co-Glycolic Acid Nanoparticles via Electrostatic Interaction for Their Enhanced Uptake and Anticancer Effect Thu, 13 Jun 2019 00:05:18 +0000 In this study, dihydroartemisinin (DAR), an anticancer agent with low toxicity, was loaded into poly-lactic-co-glycolic acid (PLGA) nanoparticles. The obtained PLGA cores were then coated with chitosan (CS) and/or folic acid (FA) by electrostatic interactions to enhance their anticancer and cellular uptake properties. DAR-loaded PLGA nanoparticles were prepared by the solvent evaporation method. CS and FA solutions at different ratios were dispersed concurrently into the PLGA suspension to facilitate electrostatic interactions and form nanosuspensions. The physiochemical properties of nanoparticles such as average particle size (), polydispersity index (PDI), zeta potential (ZP), TEM image, X-ray diffraction, and encapsulation efficiency were determined. We then determined the role of FA and CS coating on the nanoparticle surface in cytotoxicity, cellular uptake, and apoptosis. We show that the resultant nanoparticles were spherical and uniform, with a coating layer containing FA and CS covering PLGA cores with a of , PDI of , and ZP of . Both FA and CS improved the cytotoxicity of nanoparticles compared to free DAR and PLGA nanoparticles in HL-60 and KB cancer cell lines. Further, FA enhanced the cellular uptake of nanoparticles to a greater extent than CS. However, CS contributed more to apoptosis induction than FA. Chien Ngoc Nguyen, Bao Ngoc Tran, Hoa Nguyen Thi, Phong Pham Huu, and Huong Nguyen Thi Copyright © 2019 Chien Ngoc Nguyen et al. All rights reserved. Preparation and Adsorption Properties of Biochar/g-C3N4 Composites for Methylene Blue in Aqueous Solution Mon, 10 Jun 2019 13:05:23 +0000 Using straw and urea as raw materials, biochar (BC) and g-C3N4 were prepared by oxygen-free pyrolysis at 300°C and 550°C. BC/g-C3N4 was prepared by loading different amounts of g-C3N4 onto the surface of biochar and characterized by SEM and FT-IR. The adsorption effect on methylene blue (MB) was investigated from the aspects of dosage and pH. The studies of adsorption equilibrium isotherms and the kinetic and the thermodynamic parameters on the BC/g-C3N4 adsorbents are discussed. The results showed that BC/g-C3N4 0.16 g/L with a doping ratio of 1 : 3 was added to the MB solution with an initial concentration of 50 mg/L and . The adsorption rate and adsorption amount were 96.72% and 302.25 mg/g, respectively. The adsorption process included surface adsorption and intraparticle diffusion, which conformed to the pseudo-second-order kinetic model and Langmuir-Freundlich model. Thermodynamic parameters (,, and ) showed that the adsorption reaction is spontaneous, which positively correlated with temperature. Xiaodong Li Copyright © 2019 Xiaodong Li. All rights reserved. Continuous-Flow Synthesis of Thermochromic M-Phase VO2 Particles via Rapid One-Step Hydrothermal Reaction: Effect of Mixers Mon, 10 Jun 2019 10:05:27 +0000 VO2 particles are promising materials for thermochromic smart windows that reduce building energy loss. Continuous-flow hydrothermal processes showcase advantages for synthesizing VO2 particles compared with traditional batch reaction systems. Mixers play a crucial role in particle fabrication in continuous-flow systems. In this study, a Center T-Mixer and a Collision Cross-Mixer are developed and implemented in a hot water fluidized suspension reaction (HWFSR) system. The influence of the resident time on the particle phase and size was evaluated, and properties of particles derived from systems equipped with differing mixers were compared. The resulting particles were characterized using techniques of X-ray powder diffraction (XRD) analysis, scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). When compared with the Center T-Mixer, results indicate that the Collision Cross-Mixer has better control regarding the morphology and size distribution of resulting particles while improving the transition temperatures of the as-synthesized materials. HWFSR systems containing novel mixer designs are capable of producing pure M-phase VO2 particles in a single step contrary to the current reactor design that use a second postheat treatment step, and they are capable of synthesizing many other nanoparticle species, especially those requiring high temperature and pressure reaction conditions. Xiaojie Yan, William Trevillyan, Ioannina Castano, Yugang Sun, Ralph Muehleisen, and Jie Li Copyright © 2019 Xiaojie Yan et al. All rights reserved. Increased Plant Growth with Hematite Nanoparticle Fertilizer Drop and Determining Nanoparticle Uptake in Plants Using Multimodal Approach Sun, 09 Jun 2019 00:00:00 +0000 There is an emerging scientific interest in the use of nanoparticle fertilizers for enhanced agricultural and bioenergy crop production to meet the growing food and energy demands of the world. The objective of designing the nanoparticle fertilizers is to effectively deliver the required nutrients for the plants without adding large quantities of fertilizer to the environment. However, most reports on nanoparticle fertilizers so far, involved the addition of nanoparticles to the hydroponic system or the soil. In this study, we report a new modified seed presoak strategy using a drop of Fe-enriching hematite nanoparticle dispersion to enhance plant growth and production in four different legume species, i.e., chickpea, green gram, black bean, and red bean. The hematite nanoparticle fertilizer drop promoted a 230-830% increase in plant growth with green gram showing the highest increase, based on our prolonged and statistically reliable growth studies. In general, we observed an increase in the survival span of plants, a twofold increase in fruit production per plant, nearly two times faster fruit production, and healthy second-generation plants with the nanoparticle treatment; however, there were slight species-specific variations. We used a novel multimodal material characterization approach combining three techniques, hyperspectral imaging, Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma optical emission spectroscopy (ICP-OES), to evaluate the internalization and transport of the nanoparticle fertilizer within the plants. Our results indicated that the hematite nanoparticles were transported through the roots and stems and were localized in the leaves after 10 days of growth in pots of soil. Therefore, the modified seed presoaking method using a drop of hematite nanoparticle will be highly attractive in enhancing plant growth and health, while minimizing environmental impacts. Armel Boutchuen, Dell Zimmerman, Nirupam Aich, Arvid Mohammad Masud, Abdollah Arabshahi, and Soubantika Palchoudhury Copyright © 2019 Armel Boutchuen et al. All rights reserved. Graphene Quantum Dots-Modified Ternary ZnCdS Semiconductor for Enhancing Photoelectric Properties Sun, 09 Jun 2019 00:00:00 +0000 A series of graphene quantum dots-modified ZnCdS (ZnCdS/G) composites with different contents of graphene quantum dots (GQDs) were prepared by a solvothermal route and characterized via various measurements. GQDs have a type graphene height of 2 nm and exhibit an excitation-dependent PL behavior. GQDs-modified ZnCdS composites present good lattice fingers that can be assigned to the (110) plane of GQDs and (112) plane of ZnCdS. The effect of different GQDs contents on the photoelectric property of ZnCdS was investigated. The results show that the photocurrent density of ZnCdS/G first increases and achieves a maximum of 11.4 μA/cm2 with the addition of 0.06 wt% and then decreases as the GQDs content changes from 0.06 wt% to 0.12 wt%. Photocurrent counts as a function of time present a decrease of 10% and remains stable after 1600 s. Zicong Jiang, Yun Lei, Mingzhen Zhang, Zheng Zhang, and Zhong Ouyang Copyright © 2019 Zicong Jiang et al. All rights reserved. Templated Fabrication of Graphitic Carbon Nitride with Ordered Mesoporous Nanostructures for High-Efficient Photocatalytic Bacterial Inactivation under Visible Light Irradiation Mon, 03 Jun 2019 11:05:13 +0000 Biohazards are widely present in water, and a variety of waterborne diseases can be aroused by contaminated water. Therefore, the effective removal of biological hazards from water is necessary for the protection of human health. In this study, graphitic carbon nitride (g-C3N4) with ordered mesoporous nanostructures was successfully synthesized by a template method using SBA-15 as a hard template. The morphology, crystal structure, specific surface area, molecular structure, and light absorption properties of the as-prepared sample were characterized by TEM, XRD, BET, FT-IR, and UV-Vis DRS, respectively. The photocatalytic performance of the ordered mesoporous g-C3N4 was evaluated by the inactivation of Escherichia coli K-12 in water under visible light irradiation. Results showed that the bacterial inactivation efficiency can reach as high as 99% within 2 h of VL irradiation, which is 4 times higher than that of bulk g-C3N4. Moreover, the photocatalytic bacterial inactivation mechanism was revealed by a scavenging study, and the main active species in the photocatalytic inactivation process was found to be a photogenerated hole. This work will provide useful information for the development of new efficient g-C3N4-based materials for enhanced water disinfection applications by introducing ordered mesoporous nanostructures in a photocatalyst design and fabrication. Jianqin Chen, Wenting Lin, Liyan Xie, Jianhui Huang, and Wanjun Wang Copyright © 2019 Jianqin Chen et al. All rights reserved. Exploring the Internal Radiative Efficiency of Selective Area Nanowires Sun, 02 Jun 2019 00:00:00 +0000 Nanowires are ideal building blocks for next-generation solar cell applications. Nanowires grown with the selective area (SA) approach, in particular, have demonstrated very high material quality, thanks to high growth temperature, defect-free crystalline structure, and absence of external catalysts, especially in the InP material system. A comprehensive study on the influence of growth conditions and device processing on optical emission is still necessary though. This article presents an investigation of the nanowire optical properties, performed in order to optimize the internal radiative efficiency. In an initial preamble, the motivation for this study is discussed, as well as the morphology and crystallinity of the nanowires. The effect on the nanowire photoluminescence of several intrinsic and extrinsic parameters and factors are then presented in three sections: first, the influence of basic growth conditions such as the temperature and the precursor ratio is studied. Subsequently, the effects of varying dopant molar flows are explored, keeping in mind the intended solar cell application. Third, the manner in which the processing and the passivation affect the nanowire optical emission is discussed. Precise control of the growth conditions allows maximizing the nanowire internal radiative efficiency and thus their performance in solar cells and other optoelectronic devices. A. Cavalli, J. E. M. Haverkort, and E. P. A. M. Bakkers Copyright © 2019 A. Cavalli et al. All rights reserved. Laser Irradiation-Hindered Growth of Small-Diameter Single-Walled Carbon Nanotubes by Chemical Vapor Deposition Mon, 27 May 2019 10:05:25 +0000 SWNTs are synthesized on a Co/MgO catalyst using “laser-disturbed” CVD with CO as the carbon source. Compared with SWNTs grown by thermal CVD without laser irradiation (normal CVD), SWNTs synthesized under laser irradiation demonstrate the suppression of small-diameter SWNT growth, as indicated by Raman spectroscopy. Such a phenomenon is also observed for other supported catalysts, such as Co/SiO2 and Fe/MgO. Controlled experiments were carried out to clarify the effects of lasers. On the one hand, laser irradiation increases the reaction temperature locally, favoring the growth of SWNTs at a set temperature as low as 350°C. On the other hand, laser irradiation inhibits the nucleation of small SWNT caps, leading to the growth of large-diameter SWNT species. This work opens a new avenue for growing SWNTs with controlled diameters. Yunlei Fu, Xiuyun Zhang, Chunfeng Lao, Danhong Shang, and Maoshuai He Copyright © 2019 Yunlei Fu et al. All rights reserved. Flame-Retardant and Smoke Suppression Properties of Nano MgAl-LDH Coating on Bamboo Prepared by an In Situ Reaction Wed, 22 May 2019 14:15:11 +0000 In recent years, bamboo has been widely used for building materials and household goods. However, bamboo is flammable, so a flame-retardant treatment for bamboo is urgently needed. In this work, nano MgAl-layered double hydroxide (MgAl-LDH) coated on bamboo, which was called MgAl-LB, was synthesized by an in situ one-step method. To determine the optimal in situ time, the effects of different reaction times on LDH growth on the bamboo surface and the flame retardancy of the MgAl-LBs were investigated. The SEM observations show that LDH growth on the surface of bamboo was basically saturated when the in situ reaction time was 24 h. Abrasion experiments show that MgAl-LDH coating has good abrasion resistance. The fire performance of the MgAl-LBs was evaluated by cone calorimeter tests, which indicated that the THR and TSP of the MgAl-LBs were significantly lower than those of untreated bamboo. Taking into account the energy consumption problem, determining the reaction time of 24 h is the optimal reaction time. Compared with untreated bamboo, the THR and TSP of MgAl-LB prepared at 24 h decreased by 33.3% and 88.9%, respectively. Xiaoling Yao, Chungui Du, Yating Hua, Jingjing Zhang, Rui Peng, Qiuli Huang, and Hongzhi Liu Copyright © 2019 Xiaoling Yao et al. All rights reserved. Double-Layered Zirconia Films for Carbon-Based Mesoscopic Perovskite Solar Cells and Photodetectors Wed, 22 May 2019 09:05:21 +0000 Carbon-based mesoscopic perovskite solar cells (PSCs) and photodetectors were fabricated with the application of double-layered ZrO2 films, consisting of zirconia nanoparticles and microparticles for the first and the second layer, respectively. This assembly exploits the ability of the zirconia microparticles to scatter and hence diffuse the incident light, causing a more efficient illumination of the perovskite layer. As a result, the photocurrent densities produced by a photodetector and a carbon-based PSC were increased by nearly 35% and 28%, respectively, compared to devices assembled using a conventional single zirconia film. Following the increase in the photocurrent, the responsivity of the photodetector and the power conversion efficiency of the PSC were increased analogously, due to the improved light harvesting efficiency of the perovskite layer. Parameters, such as the total thickness, the roughness, and the crystallinity of the films, were examined. Differences in the grain size and in the crystal planes of the perovskite were observed and evaluated. These results demonstrate that a double-layered ZrO2 film can enhance the efficiency of solar cells and photodetectors, enhancing the prospects for their potential commercialization. George Syrrokostas, George Leftheriotis, and Spyros N. Yannopoulos Copyright © 2019 George Syrrokostas et al. All rights reserved. Enhanced Biocompatibility and Antibacterial Activity of Selective Laser Melting Titanium with Zinc-Doped Micro-Nano Topography Tue, 21 May 2019 09:05:20 +0000 Selective laser melting (SLM) titanium is a suitable material for use in customized implants. However, long-term implant survival requires both successful osseointegration and promising antibacterial characteristics. Native SLM titanium thus requires proper modifications to improve its bioactivity and antibacterial efficacy. Micro-arc oxidation (MAO) was conducted on sandblasted SLM substrate to form a microporous TiO2 coating. Subsequently, hydrothermal treatment was applied to fabricate micro-nano zinc-incorporated coatings with different Zn content (1 mM-Zn and 100 μM-Zn). Surface characterization was performed using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, a three-dimensional profilometer, and a contact angle measuring device. The osteoblast-like cell line MC3T3-E1, Subclone 14, was used in cell viability assays to evaluate adhesion, proliferation, and ALP activity. An antibacterial assay was conducted using Streptococcus sanguinis and Fusobacterium nucleatum. Zn-incorporated samples exhibited higher adhesion, proliferation, and differentiation than did SLM and MAO samples. 100 μM Zn samples exhibited the highest proliferation, and 1 mM-Zn samples manifested the highest ALP activity. In addition, Zn-incorporated samples exerted inhibitory effects on both Streptococcus sanguinis and Fusobacterium nucleatum. Combining micro-arc oxidation and hydrothermal treatment, we successfully fabricated a novel Zn-incorporated coating on a microporous SLM surface which possesses both outstanding bioactivity and antibacterial efficacy. Fan Wu, Ruogu Xu, Xiaolin Yu, Jiamin Yang, Yun Liu, Jianglin Ouyang, Chunyu Zhang, and Feilong Deng Copyright © 2019 Fan Wu et al. All rights reserved. LED-Based Light Source Combined with Quantum Dot for Spectral Imaging Mon, 20 May 2019 14:05:10 +0000 Quantum dot (QD) is a kind of semiconductor nanoparticle and shows photoluminescence, in which the light with narrow spectral band is emitted from the QD after the absorption of the excitation light. In this study, it is demonstrated that the LED-based light source combined with a QD film can be applied to spectral imaging. The polymer film with QD was prepared by photopolymerization. Through measurement of the emission spectrum, it was confirmed that the optical intensity at the peak wavelength of the spectral bands of 410 and 540 nm could be controlled by changing the thickness of the film. In the study using a home-made phantom mimicking blood vessels, the patterns’ contrast in the phantom images could be enhanced by using LED combined with QD as compared with the white light image. The LED light combined with the QD film provides a useful solution for illumination for spectral imaging. Young Min Bae, Dong-Goo Kang, Ki Young Shin, Wonju Lee, and Dong-Wook Yoo Copyright © 2019 Young Min Bae et al. All rights reserved. Facile Synthesis of Yb3+- and Er3+-Codoped LiGdF4 Colloidal Nanocrystals with High-Quality Upconversion Luminescence Thu, 16 May 2019 14:05:07 +0000 Herein, we synthesized high-quality colloidal nanocrystals of Yb3+/Er3+-codoped LiGdF4 with intense green emission by using a facile route and turning the associated reaction parameters. Moreover, we probed the effects of reaction conditions on nanocrystal properties (crystal structure, morphology, and luminescence) and gained valuable mechanistic insights into nucleation and growth processes. Sample purity was found to depend on LiOH·H2O concentration, reaction temperature, and time, which allowed us to manipulate sample purity and thus obtain species ranging from mixtures of LiGdF4:Yb3+/Er3+ with GdF3 to pure tetragonal-phase LiGdF4:Yb3+/Er3+. Investigation of upconversion luminescence properties and the luminescence lifetime of as-prepared samples revealed that LiGdF4 is a promising host material for realizing the desired upconversion luminescence. Lu Zi, Dan Zhang, and Gejihu De Copyright © 2019 Lu Zi et al. All rights reserved. Polymeric Nanogels as Versatile Nanoplatforms for Biomedical Applications Thu, 16 May 2019 11:05:34 +0000 Nanomaterials have found extensive biomedical applications in the past few years because of their small size, low molecular weight, larger surface area, enhanced biological, and chemical reactivity. Among these nanomaterials, nanogels (NGs) are promising drug delivery systems and are composed of cross-linked polymeric nanoparticles ranging from 100 to 200 nm. NGs represent an innovative zone of research with speedy developments taking place on a daily basis. An incredible amount of focus is placed on the fabrication of NGs with novel polymers to achieve better control over the drug release. This review article covers a number of aspects of NGs including their types, associated pros and cons, and methods of preparation along with technical and economical superiority and therapeutic efficacy over each other. The last part of review summarizes the applications of NGs in the drug delivery and treatment of various diseases including brain disease, cardiovascular diseases, oxidative stress, diabetes, cancer therapy, tissue engineering, gene therapy, inflammatory disorders, pain management, ophthalmic and autoimmune diseases, and their future challenges. NGs appear to be an outstanding nominee for drug delivery systems, and further study is required to explore their interactions at the cellular and molecular levels. Fakhara Sabir, Muhammad Imran Asad, Maimoona Qindeel, Iqra Afzal, Muhammad Junaid Dar, Kifayat Ullah Shah, Alam Zeb, Gul Majid Khan, Naveed Ahmed, and Fakhar-ud Din Copyright © 2019 Fakhara Sabir et al. All rights reserved. Gap Prediction in Hybrid Graphene-Hexagonal Boron Nitride Nanoflakes Using Artificial Neural Networks Thu, 16 May 2019 11:05:31 +0000 The electronic properties of graphene nanoflakes (GNFs) with embedded hexagonal boron nitride (hBN) domains are investigated by combined ab initio density functional theory calculations and machine-learning techniques. The energy gaps of the quasi-0D graphene-based systems, defined as the differences between LUMO and HOMO energies, depend not only on the sizes of the hBN domains relative to the size of the pristine graphene nanoflake but also on the position of the hBN domain. The range of the energy gaps for different configurations increases as the hBN domains get larger. We develop two artificial neural network (ANN) models able to reproduce the gap energies with high accuracies and investigate the tunability of the energy gap, by considering a set of GNFs with embedded rectangular hBN domains. In one ANN model, the input is in one-to-one correspondence with the atoms in the GNF, while in the second model the inputs account for basic structures in the GNF, allowing potential use in upscaled systems. We perform a statistical analysis over different configurations of ANNs to optimize the network structure. The trained ANNs provide a correlation between the atomic system configuration and the magnitude of the energy gaps, which may be regarded as an efficient tool for optimizing the design of nanostructured graphene-based materials for specific electronic properties. G. A. Nemnes, T. L. Mitran, and A. Manolescu Copyright © 2019 G. A. Nemnes et al. All rights reserved. Interaction of Mitoxantrone-Loaded Cholesterol Modified Pullulan Nanoparticles with Human Serum Albumin and Effect on Drug Release Thu, 16 May 2019 10:05:24 +0000 To clarify nanoparticle-protein interaction and their action characteristics, the interactions between MTO-CHP NPs and human serum albumin (HSA) were studied by isothermal titration calorimetry (ITC), fluorescence spectroscopy, dynamic light scattering (DLS), and circular dichroism spectroscopy (CD). Hydrophobically modified pullulan (CHP) nanoparticles (NPs) loaded with mitoxantrone (MTO) were prepared (MTO-CHP NPs) with size 166.9 nm. The spherical shape was verified by transmission electron microscopy (TEM). The ITC results demonstrated an interaction between MTO-CHP NPs mainly by hydrophobic interaction force, electrostatic force, and hydrogen bonding. The mean binding constant was and mean HSA coverage . MTO-CHP NPs could quench the fluorescence intensity of HSA, which gradually decreased to be balanced in 9 h and indicated the completion of the complexation. The size and zeta potential changes of the combined particle were dynamically detected with DLS at 0, 3, 6, 9, 12, 15, and 18 h. When the reaction was completed at 9 h, the particle size and potential remained stable, accompanied by a size change from 89.91 to about 145 nm and potential change from -15 to -3 mV, respectively. The results of CD measurement showed that the change in ellipticity of HSA at 208 nm was similar to the fluorescence spectra and DLS measurements with MTO-CHP NPs combined with HSA. At the beginning of the reaction, the proportion of α-helix was 52.3% to 43.7%, which decreased by 39.1% at compound stabilization. The release of MTO from MTO-CHP NPs at was significantly accelerated, whereas that of MTO from HSA-MTO-CHP NPs was significantly reduced, and the drug release was significantly slowed down even under acidic conditions, which indicates the beneficial effect of HSA on the persistence and stability of the HSA-MTO-CHP NP compound. Liming Yuan, Bu Guo, Wu Zhong, Yu Nie, Xiaoyan Yao, Xiaofeng Peng, Rong Wang, Hongyuan Yu, Shanyi Yang, Chunlian He, Xiaojun Tao, and Qiufang Zhang Copyright © 2019 Liming Yuan et al. All rights reserved. Optimization of Tb3+/Gd3+ Molar Ratio for Rapid Detection of Naja Atra Cobra Venom by Immunoglobulin G-Conjugated GdPO4·nH2O : Tb3+ Nanorods Thu, 16 May 2019 10:05:22 +0000 In this report, GdPO4·nH2O and Tb3+-doped GdPO4·nH2O nanorods@silica-NH2 conjugated with IgG antibody were synthesized by applying hydrothermal, sol-gel, and coprecipitation methods successively. The effects of Tb3+/Gd3+ molar ratios of reactants on the size, morphology, and luminescence of the synthesized samples were also investigated. For the optimized GdPO4·nH2O : Tb3+ sample, uniform nanorods sizing from 10 to 30 nm in diameter and from 200 to 300 nm in length were obtained with the strongest luminescence in green color with narrow bands under the UV excitation (325 nm). The results revealed that, after being coated with silica-NH2 and conjugated with IgG antibody, all luminescence characteristic peaks of GdPO4·nH2O : Tb3+ corresponding to the process of energy transfer from Gd3+ to Tb3+ and then the emission from 5D4 → 7FJ () of Tb3+ were still clearly observed. The initial results of using the optimized Tb3+-doped GdPO4·nH2O nanorods@silica-NH2 conjugated with IgG antibody for rapid selective detection of Naja atra cobra venom were also reported. Pham Thi Lien, Nguyen Thanh Huong, Tran Thu Huong, Hoang Thi Khuyen, Nguyen Thi Ngoc Anh, Nguyen Duc Van, Nguyen Ngoc Tuan, Vu Xuan Nghia, and Le Quoc Minh Copyright © 2019 Pham Thi Lien et al. All rights reserved. Effect of Ge Nanoparticles in the Core of Photonic Crystal Fiber on Supercontinuum Generation Thu, 16 May 2019 09:05:23 +0000 The effect of Ge nanoparticle (Ge NP) incorporation in the germanosilicate glass core of the photonic crystal fiber (PCF) on supercontinuum generation (SCG) was investigated. The Ge NP-doped germanosilicate glass core PCF was fabricated by using the modified chemical vapor deposition (MCVD) and the stack-and-draw processes. The average diameter of Ge NPs embedded in the core of the PCF was 4.2 nm. The absorption peaks at 480 nm and 515 nm and the band from 600 to 800 nm were attributed to the Ge NPs in the core of the PCF. SCG of the 490 nm bandwidth (598 nm~1088 nm) with a conversion efficiency of 31% was obtained by pumping at 800 nm with the Ti:sapphire femtosecond laser of 160 mW with 35 fs pulse at 1 kHz repetition rate, resulting from the enhanced optical nonlinearity from Ge NPs as well as the PCF structure of the fiber. Seongmin Ju, Yuseung Lee, Seongmook Jeong, Youngwoong Kim, In-Sik Kim, Do-Kyeong Ko, and Won-Taek Han Copyright © 2019 Seongmin Ju et al. All rights reserved. Fabrication of Nanoparticle-Stacked 1,1-Diamino-2,2-Dinitroethylene (FOX-7) Microspheres with Increased Thermal Stability Tue, 14 May 2019 10:05:16 +0000 Nanoparticle-stacked 1,1-diamino-2,2-dinitroethylene (FOX-7) microspheres were successfully prepared by spray-drying, and rod-shaped FOX-7 was obtained by the solvent/nonsolvent method for comparison. The microstructure features of samples were characterized using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD), and the thermal properties were also investigated by differential scanning calorimetry (DSC). From the SEM analysis, the particle size of the rod-shaped FOX-7 is about 10 μm, whereas FOX-7 microspheres having a particle size ranging from 1 to 5 μm are formed by stacking nanoparticles with size of 100-250 nm. The crystal form of the samples prepared by the two methods did not change. The thermal performance test results showed that the rd-shaped FOX-7 had no significant change compared with the raw FOX-7, while the nanoparticle-stacked FOX-7 microspheres had higher thermal stability. Yuanping Zhang, Conghua Hou, Xinlei Jia, Jinyu Wang, and Yingxin Tan Copyright © 2019 Yuanping Zhang et al. All rights reserved. Metal-Organic Framework MIL-101: Synthesis and Photocatalytic Degradation of Remazol Black B Dye Tue, 14 May 2019 10:05:14 +0000 In the present paper, the synthesis of metal-organic framework MIL-101 and its application in the photocatalytic degradation of Remazol Black B (RBB) dye have been demonstrated. The obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption isotherms at 77 K. It was found that MIL-101 synthesized under optimal conditions exhibited high crystallinity and specific surface area (3360 m2·g-1). The obtained MIL-101 possessed high stability in water for 14 days and several solvents (benzene, ethanol, and water at boiling temperature). Its catalytic activities were evaluated by measuring the degradation of RBB in an aqueous solution under UV radiation. The findings show that MIL-101 was a heterogeneous photocatalyst in the degradation reaction of RBB. The mechanism of photocatalysis was considered to be achieved by the electron transfer from photoexcited organic ligands to metallic clusters in MIL-101. The kinetics of photocatalytic degradation reaction were analyzed by using the initial rate method and Langmuir-Hinshelwood model. The MIL-101 photocatalyst exhibited excellent catalytic recyclability and stability and can be a potential catalyst for the treatment of organic pollutants in aqueous solutions. Pham Dinh Du, Huynh Thi Minh Thanh, Thuy Chau To, Ho Sy Thang, Mai Xuan Tinh, Tran Ngoc Tuyen, Tran Thai Hoa, and Dinh Quang Khieu Copyright © 2019 Pham Dinh Du et al. All rights reserved. Biomass Derivative Valorization Using Nano Core-Shell Magnetic Materials Based on Keggin-Heteropolyacids: Levulinic Acid Esterification Kinetic Study with N-Butanol Sun, 12 May 2019 00:00:00 +0000 Magnetic materials based on Keggin heteropolyacids immobilized on mesoporous silica-coated magnetite particles with a core-shell structure were synthesized. The activity of the catalyst was studied in the esterification reaction of levulinic acid with n-butanol, and its kinetics was studied by the systematic variation of several reaction parameters, such as stirring speed, catalyst loading, molar ratio of reactants, and temperature. It was also seen that the reaction was free from any external mass transfer as well as intraparticle diffusion limitations and was intrinsically kinetically controlled. A second-order kinetic equation was found to be consistent with the experimental data. Also, an experimental activation energy of 17 kcal/mol was found. A solvent-free condition for this reaction has also added the green chemistry perception to the reaction. In addition, the resulting catalyst can be used repeatedly without significant decrease in activity. Angélica M. Escobar, Mirta N. Blanco, José J. Martínez, Jairo A. Cubillos, Gustavo P. Romanelli, and Luis R. Pizzio Copyright © 2019 Angélica M. Escobar et al. All rights reserved. Biocompatibility of Developing 3D-Printed Tubular Scaffold Coated with Nanofibers for Bone Applications Thu, 09 May 2019 15:05:02 +0000 3D printing with controlled microarchitectures has gained traction in a wide variety of fields, including bone tissue engineering, because it represents an exciting alternative for the synthesis of new scaffolds due to its rapid manufacturing process, high precision, cost-effectiveness, and ease of use. Thus, this study is aimed at evaluating the biocompatibility response of a 3D-printed tubular scaffold coated by a layer of 7% PLA nanofibers. The morphology, structure, and chemical composition of the 3D-printed tubular scaffold were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and surface property analysis by profilometry. The biocompatibility response of the scaffold was assessed by cell adhesion, proliferation, and cell-material interactions of human fetal osteoblasts. Our results showed that 3D printing allowed obtaining similar and reproducible structures and the biocompatibility assays showed that nanofiber coating of the surface of the 3D tubular scaffold promoted an improvement on cell attachment, proliferation, and the morphology of osteoblast cells when compared with a noncoated scaffold. In conclusion, the surface of the 3D-printed tubular scaffold could be improved by the deposition of a nanofiber layer to render a more mimetic and active topography with excellent cellular biocompatibility for bone tissue applications. Febe Carolina Vazquez-Vazquez, Osmar Alejandro Chanes-Cuevas, David Masuoka, Jesús Arenas Alatorre, Daniel Chavarria-Bolaños, José Roberto Vega-Baudrit, Janeth Serrano-Bello, and Marco Antonio Alvarez-Perez Copyright © 2019 Febe Carolina Vazquez-Vazquez et al. All rights reserved. Synthesis and Photocatalytic Properties of Co-Doped Zn1-xCoxMn2O Hollow Nanospheres Thu, 09 May 2019 09:05:30 +0000 A series of Co-doped Zn1-xCoxMn2O nanocrystals with a spinel structure were successfully prepared by hydrothermal method, and the influence of Co doping concentration on the microstructure, morphology, elemental composition, and optical and photocatalytic properties of the samples was characterized. The experimental results show that all samples exhibit a tetragonal structure, Co2+ ions are successfully substituted for the lattice site of Zn2+ to generate ZnMn2O4 nanocrystals, and the crystalline size decreases as Co-doped concentration increase. The morphologies are loose hollow microsphere structures. The band gap of samples is smaller than that of pure ZnMn2O4 and has been red shifted. The photocatalytic activity of doped samples is obviously higher than that of pure ZnMn2O4 samples for the photodegradation of MO under visible light irradiation. All these results demonstrate that Co-doped spinel ZnMn2O4 nanocrystals are a meaningful choice for photocatalytic degradation of the pollutants. Long Ma, Zhiqiang Wei, Xueliang Zhu, Jiahao Liang, and Xudong Zhang Copyright © 2019 Long Ma et al. All rights reserved. Structure and Biological Properties of Surface-Engineered Carbon Nanofibers Thu, 09 May 2019 09:05:27 +0000 The aim of this work was to manufacture, using the electrospinning technique, polyacrylonitrile- (PAN-) based carbon nanofibers in the form of mats for biomedical applications. Carbon nanofibers obtained by carbonization of the PAN nanofibers to 1000°C (electrospun carbon nanofibers (ECNF)) were additionally oxidized in air at 800°C under reduced pressure (electrospun carbon nanofibers oxidized under reduced pressure (ECNFV)). The oxidative treatment led to partial removal of a structurally less-ordered carbon phase from the near-surface region of the carbon nanofibers. Both types of carbon fibrous mats were studied using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (TEM), XRD, and Raman spectroscopy. The morphology, microstructure, and surface properties of both materials were analyzed. The oxidative treatment of carbon nanofibers significantly changed their surface morphology and physical properties (wettability, surface electrical resistance). Biological tests (genotoxicity, fibroblast, and human osteoblast-like MG63 cultures) were carried out in contact with both materials. Genotoxicity study conducted by means of comet assays revealed significant differences between both carbon nanofibers. Fibroblasts contacted with the as-received carbon nanofibers (ECNF) showed a significantly higher level of DNA damage compared to control and oxidized carbon nanofibers (ECNFV). The ECNFV nanofibers were not cytotoxic, whereas ECNF nanofibers contacted with both types of cells indicated a cytotoxic effect. The ECNFV introduced into cell culture did not affect the repair processes in the cells contacting them. Wojciech Smolka, Agnieszka Panek, Maciej Gubernat, Aneta Szczypta-Fraczek, Piotr Jelen, Czeslawa Paluszkiewicz, Jaroslaw Markowski, and Marta Blazewicz Copyright © 2019 Wojciech Smolka et al. All rights reserved. Quantitative Phase-Field Simulation of Composition Partition and Separation Kinetics of Nanoscale Phase in Fe-Cr-Al Alloy Wed, 08 May 2019 10:05:17 +0000 Phase separation of the Cr-enriched nanoscale α phase in the Fe-38 at.% Cr-10 at.% Al alloy is studied by utilizing phase-field simulation. The partition of elements in the α and α phases is clarified with the composition evolution through the α/α phase interface, and the separation kinetics is quantitatively investigated by the temporal evolution of the size and volume fraction of the α phase. Aluminum partitions into the Fe-enriched α phase and depletes in the α phase, and the partition coefficient decreases as the temperature changes from 720 K to 760 K for the steady-state coarsening stage. As the temperature increases, the initial change rate of the volume fraction of the α phase is faster, indicating an accelerated phase separation. At the coarsening stage, the average particle distance and coarsening rate constant of the α phase increase with increased temperature, and the ratio of the Ostwald ripening is dominating compared with coalescence coarsening. The element partition and kinetics evolution of the α phase with temperature are helpful for the morphology and property predication of nanoscale precipitates. Shi Chen, Yongsheng Li, Shujing Shi, and Shengshun Jin Copyright © 2019 Shi Chen et al. All rights reserved.