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Loredana Protesescu, Sergii Yakunin, Sudhir Kumar, Janine Bär, Federica Bertolotti, Norberto Masciocchi, Antonietta Guagliardi, Matthias Grotevent, Ivan Shorubalko, Maryna I Bodnarchuk, Chih-Jen Shih, Maksym V Kovalenko
Colloidal nanocrystals (NCs) of APbX3-type lead halide perovskites [A=Cs+, CH3NH3+ (methylammonium or MA+) or CH(NH2)2+ (formamidinium or FA+); X=Cl-, Br-, I-] have recently emerged as highly versatile photonic sources for applications ranging from simple photoluminescence down-conversion (e.g., for display backlighting) to light emitting diodes. From the perspective of spectral coverage, a formidable challenge facing the use of these materials is how to obtain stable emissions in the red and infrared spectral regions covered by the iodide-based compositions...
February 23, 2017: ACS Nano
Lichao Sun, Qingfeng Zhang, Guangfang Grace Li, Esteban Villarreal, Xiaoqi Fu, Hui Wang
Kinetically controlled, seed-mediated coreduction provides a robust and versatile synthetic approach to multimetallic nanoparticles with precisely controlled geometries and compositions. Here we demonstrate that single-crystalline cylindrical Au nanorods selectively transform into a series of structurally distinct Au@Au-Pd alloy core-shell bimetallic nanorods with exotic multifaceted geometries enclosed by specific types of facets upon seed-mediated Au-Pd coreduction under diffusion controlled conditions. By adjusting several key synthetic parameters, such as the Pd/Au precursor ratio, the reducing agent concentration, the capping surfactant concentration, and foreign metal ion additives, we have been able to simultaneously fine-tailor the atomic-level surface structures and fine-tune the compositional stoichiometries of the multifaceted Au-Pd bimetallic nanorods...
February 23, 2017: ACS Nano
Tobias Bollhorst, Kurosch Rezwan, Michael Maas
Utilizing colloidal particles for the assembly of the shell of nano- and microcapsules holds great promise for the tailor-made design of new functional materials. Increasing research efforts are devoted to the synthesis of such colloidal capsules, by which the integration of modular building blocks with distinct physical, chemical, or morphological characteristics in a capsule's shell can result in novel properties, not present in previous encapsulation structures. This review will provide a comprehensive overview of the synthesis strategies and the progress made so far of bringing nano- and microcapsules with shells of densely packed colloidal particles closer to application in fields such as chemical engineering, materials science, or pharmaceutical and life science...
February 23, 2017: Chemical Society Reviews
Hironori Nagai, Austen Poteet, Xu A Zhang, Chih-Hao Chang
Light interactions with colloidal particles can generate a variety of complex three-dimensional (3D) intensity patterns, which can be utilized for nanolithography. The study of particle-light interactions can add more types of intensity patterns by manipulating key factors. Here we investigate a novel 3D nanolithography technique using colloidal particles under two-beam coherent illuminations. The fabricated 3D nanostructures are hollow, nested within periodic structures, and possess multiple chamber geometry...
February 23, 2017: Nanotechnology
Jing Li, Laihao Luo, Hongwen Huang, Chao Ma, Zhizhen Ye, Jie Zeng, Haiping He
Fundamental to understanding and predicting the optoelectronic properties of semiconductors is the basic parameters of excitons such as oscillator strength and exciton binding energy. However, such knowledge of CsPbBr3 perovskite, a promising optoelectronic material, is still unexplored. Here we demonstrate that quasi-two-dimensional (quasi-2D) CsPbBr3 nanoplatelets (NPLs) with 2D exciton behaviors serve as an ideal system for the determination of these parameters. It is found that the oscillator strength of CsPbBr3 NPLs is up to 1...
February 23, 2017: Journal of Physical Chemistry Letters
Mark-Robert Kalus, Niko Bärsch, René Streubel, Emine Gökce, Stephan Barcikowski, Bilal Gökce
During laser synthesis of colloids, cavitation bubbles with lifetimes in the microsecond-scale form and shield the laser pulse leading to a decrease in nanoparticle output. A second type of productivity-limiting bubble that severely affects the productivity of the process is often neglected. With lifetimes from milliseconds to seconds, these persistent bubbles are systematically studied in this work by quantifying their composition, amount, size and dwell time in liquids with different viscosities and by relating the results to the nanoparticle productivities...
February 23, 2017: Physical Chemistry Chemical Physics: PCCP
Benjamin Trefz, Jonathan Tammo Siebert, Thomas Speck, Kurt Binder, Peter Virnau
We study numerically the critical behavior of a modified, active Asakura-Oosawa model for colloid-polymer mixtures. The colloids are modeled as self-propelled particles with Vicsek-like interactions. This system undergoes phase separation between a colloid-rich and a polymer-rich phase, whereby the phase diagram depends on the strength of the Vicsek-like interactions. Employing a subsystem-block-density distribution analysis, we determine the critical point and make an attempt to estimate the critical exponents...
February 21, 2017: Journal of Chemical Physics
Tonnishtha Dasgupta, John R Edison, Marjolein Dijkstra
Using event-driven Brownian dynamics simulations, we investigate the epitaxial growth of hard-sphere crystals with a face-centered-cubic (fcc) structure on the three densest cross-sectional planes of the fcc: (i) fcc (100), (ii) fcc (111), and (iii) fcc (110). We observe that for high settling velocities, large fcc crystals with very few extended defects grow on the fcc (100) template. Our results show good agreement with the experiments of Jensen et al. [Soft Matter 9, 320 (2013)], who observed such large fcc crystals upon centrifugation on an fcc (100) template...
February 21, 2017: Journal of Chemical Physics
D M Nozdrenko, D O Zavodovskyi, T Yu Matvienko, S Yu Zay, K I Bogutska, Yu I Prylutskyy, U Ritter, P Scharff
The therapeutic effect of pristine C60 fullerene aqueous colloid solution (C60FAS) on the functioning of the rat soleus muscle at ischemic injury depending on the time of the general pathogenesis of muscular system and method of administration C60FAS in vivo was investigated. It was found that intravenous administration of C60FAS is the optimal for correction of speed macroparameters of contraction for ischemic muscle damage. At the same time, intramuscular administration of C60FAS shows pronounced protective effect in movements associated with the generation of maximum force responses or prolonged contractions, which increase the muscle fatigue level...
December 2017: Nanoscale Research Letters
Andrew J Hargreaves, Peter Vale, Jonathan Whelan, Carlos Constantino, Gabriela Dotro, Pablo Campo, Elise Cartmell
The distribution of Cu, Pb, Ni and Zn between particulate, colloidal and truly dissolved size fractions in wastewater from a trickling filter treatment plant was investigated. Samples of influent, primary effluent, humus effluent, final effluent and sludge holding tank returns were collected and separated into particulate (i.e. > 0.45 μm), colloidal (i.e. 1 kDa to 0.45 μm), and truly dissolved (i.e. < 1 kDa) fractions using membrane filters. In the influent, substantial proportions of Cu (60%), Pb (67%), and Zn (32%) were present in the particulate fraction which was removed in conjunction with suspended particles at the works in subsequent treatment stages...
February 7, 2017: Chemosphere
Auke de Vries, Yuly Lopez Gomez, Bas Jansen, Erik van der Linden, Elke Scholten
Proteins are known to be effective building blocks when it comes to structure formation in aqueous environments. Recently, we have shown that submicron colloidal protein particles can also be used to provide structure to liquid oil and form so-called oleogels.1 Preventing extensive agglomeration of these submicron building blocks is a prerequisite to allow for efficient structure formation. This was achieved by applying a solvent exchange procedure to transfer the building blocks from water to oil. The aim of the current paper was to elucidate on the enhanced stability against agglomeration of heat-set whey protein isolate (WPI) aggregates in oil after applying such a solvent exchange procedure...
February 22, 2017: ACS Applied Materials & Interfaces
Lamees Nayef, Rafael Castiello, Maryam Tabrizian
Aggregation is frequently encountered during coating nanoparticles, especially when the core is not solid and the coating polyelectrolytes are weak. Here, the coating of a nanoliposome with two weak polyelectrolytes, alginate and chitosan, is investigated. First, quartz crystal microbalance with dissipation, atomic force microscopy, scanning electron microscopy, and energy dispersive spectroscopy analyses confirm the feasibility of firm adsorption of up to 16 layers of weak polyelectrolytes to the liposomal surface...
February 22, 2017: Macromolecular Bioscience
Gracia Mendoza, Anna Regiel-Futyra, Vanesa Andreu, Victor Sebastian, Agnieszka Kyzioł, Grazyna Stochel, Manuel Arruebo
Pathogenic bacteria are able to develop resistance mechanisms to avoid the antimicrobial potential of antibiotics becoming an increasing problem for the healthcare systems. The search for more effective and selective antimicrobial materials, though not harmful to mammalian cells, seems imperative. Herein we propose the use of gold-chitosan nanocomposites as effective bactericidal materials avoiding the damage to human cells. Nanocomposites were obtained taking advantage of the reductive and stabilizing action of chitosan solutions on two different gold precursor concentrations...
February 22, 2017: ACS Applied Materials & Interfaces
Xiaofeng Liu, Qiangbing Guo, Jianrong Qiu
Low-dimensional (LD) materials demonstrate intriguing optical properties, which lead to applications in diverse fields, such as photonics, biomedicine and energy. Due to modulation of electronic structure by the reduced structural dimensionality, LD versions of metal, semiconductor and topological insulators (TIs) at the same time bear distinct nonlinear optical (NLO) properties as compared with their bulk counterparts. Their interaction with short pulse laser excitation exhibits a strong nonlinear character manifested by NLO absorption, giving rise to optical limiting or saturated absorption associated with excited state absorption and Pauli blocking in different materials...
February 22, 2017: Advanced Materials
John M McBride, Carlos Avendaño
We investigate the phase behaviour and self-assembly of convex spherical caps using Monte Carlo simulations. This model is used to represent the main features observed in experimental colloidal particles with mushroom-cap shape [Riley et al., Langmuir, 2010, 26, 1648]. The geometry of this non-centrosymmetric convex model is fully characterized by the aspect ratio χ* defined as the spherical cap height to diameter ratio. We use NPT Monte Carlo simulations combined with free energy calculations to determine the most stable crystal structures and the phase behaviour of convex spherical caps with different aspect ratios...
February 22, 2017: Soft Matter
Ryuji Ohashi, Yukihiro Murase, Miyuki Matsubara, Yasuhiko Watarai, Takehito Igarashi, Iwao Sugitani, Zenya Naito
BACKGROUND: Solid variant of papillary thyroid carcinoma is a rare subtype of papillary thyroid carcinoma (PTC) containing a solid component (SC), and thus its cytological and clinicopathological features remain elusive. We examined fine needle aspiration (FNA) cytological features of PTC with variable degrees of SC (20-80% of the tumor)(PTCSC) in comparison to well-differentiated PTC (WPTC). METHODS: Twenty-six cases of PTCSC were histologically stratified into major-SC (SC >50% of the tumor) and minor-SC (<49%) groups...
February 22, 2017: Diagnostic Cytopathology
Karim Benhabib, Marie-Odile Simonnot, Pierre Faure, Michel Sardin
Brownfield soils may contain high levels of organic pollutants particularly polycyclic aromatic hydrocarbons (PAHs). It is essential to predict their migration and fate and to evaluate the risk of transfer to sensitive targets, such as water resources, ecosystems and human health. In this study, soil samples have been taken from an experimental contaminated site of former steel activities located at Homecourt (Lorraine, France). These samples have been lixiviated in laboratory column in water-saturated condition at room temperature...
February 21, 2017: Environmental Science and Pollution Research International
Si-Jing Ding, Da-Jie Yang, Jin-Ling Li, Gui-Ming Pan, Liang Ma, Yong-Jie Lin, Jia-Hong Wang, Li Zhou, Min Feng, Hongxing Xu, Shiwu Gao, Qu-Quan Wang
The surface plasmon resonance (SPR) of metal nanoparticles exhibits quantum behaviors as the size decreases owing to the transitions of quantized conduction electrons, but most studies are limited to the monotonous SPR blue-shift caused by off-resonant transitions. Here, we demonstrate the nonmonotonous SPR red-shift caused by resonant electron transitions and photocatalytic activity enhanced by the quantum plasmon resonance of colloidal gold nanoparticles. A maximal SPR wavelength and the largest photocatalytic activity are observed in the quantum regime for the first time for the gold nanoparticles with a diameter of 3...
February 21, 2017: Nanoscale
Ming Yang, Henry Chan, Gongpu Zhao, Joong Hwan Bahng, Peijun Zhang, Petr Král, Nicholas A Kotov
Nanoscale compartments are one of the foundational elements of living systems. Capsids, carboxysomes, exosomes, vacuoles and other nanoshells easily self-assemble from biomolecules such as lipids or proteins, but not from inorganic nanomaterials because of difficulties with the replication of spherical tiling. Here we show that stabilizer-free polydispersed inorganic nanoparticles (NPs) can spontaneously organize into porous nanoshells. The association of water-soluble CdS NPs into self-limited spherical capsules is the result of scale-modified electrostatic, dispersion and other colloidal forces...
March 2017: Nature Chemistry
Chenglin Wang, Shiying Ma, Yi Hu, Rong Wang
We investigated the self-assembly of surfactant-like amphiphile consisting of a hydrophilic head and a hydrophobic tail using dissipative particle dynamics method. By controlling the interaction parameter between the hydrophilic head and the solvent, the length of hydrophobic tail, the size of hydrophilic head, and the polymer concentration, we found seven self-assembled morphologies, including sphere-like micelle, pomegranate-like micelle, hierarchical colloidal polymeric structure, pomegranate-like columnar structure, branched hybrid structure, disk-like micelle, and vesicle...
February 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
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