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Silicon nanoparticles

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https://www.readbyqxmd.com/read/29136418/nano-object-release-during-machining-of-polymer-based-nanocomposites-depends-on-process-factors-and-the-type-of-nanofiller
#1
Yaobo Ding, Wendel Wohlleben, Mael Boland, Klaus Vilsmeier, Michael Riediker
We tested the nanomaterial release from composites during two different mechanical treatment processes, automated drilling and manual sawing. Polyurethane (PU) polymer discs (1-cm thickness and 11-cm diameter) were created using different nanomaterial fillers: multiwall carbon nanotubes (MWCNT), carbon black (CB), silicon dioxide (SiO2), and an unfilled PU control. Drilling generated far more submicron range particles than sawing. In the drilling experiments, none of the tested nanofillers showed a significant influence on particle number concentrations or sizes, except for the PU/MWCNT samples, from which larger particles were released than from control samples...
November 10, 2017: Annals of Work Exposures and Health
https://www.readbyqxmd.com/read/29135463/new-method-for-mbe-growth-of-gaas-nanowires-on-silicon-using-colloidal-au-nanoparticles
#2
Alexei Bouravleuv, Igor Ilkiv, Rodion Reznik, Konstantin Kotlyar, Ilya Soshnikov, George Cirlin, Pavel Brunkov, Demid Kirilenko, Leonid V Bondarenko, Aleksandr Nepomnyaschiy, Dimitry V Gruznev, Andrey V Zotov, Alexander Saranin, Veer Dhaka, Harri Lipsanen
We present a new method for the deposition of colloidal Au nanoparticles on the surface of silicon substrates based on short-time Ar plasma treatment without the use of any polymeric layers. The elaborated method is compatible with molecular beam epitaxy, which allowed us to carry out the detailed study of GaAs nanowire synthesis on Si(111) substrates using colloidal Au nanoparticles as seeds for their growth. The results obtained elucidated the causes of the difference between the initial nanoparticle sizes and the diameters of the grown nanowires...
November 14, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29127333/a-light-activated-antimicrobial-surface-is-active-against-bacterial-viral-and-fungal-organisms
#3
Tim Walker, Melisa Canales, Sacha Noimark, Kristopher Page, Ivan Parkin, Jane Faull, Manni Bhatti, Lena Ciric
Evidence has shown that environmental surfaces play an important role in the transmission of nosocomial pathogens. Deploying antimicrobial surfaces in hospital wards could reduce the role environmental surfaces play as reservoirs for pathogens. Herein we show a significant reduction in viable counts of Staphylococcus epidermidis, Saccharomyces cerevisiae, and MS2 Bacteriophage after light treatment of a medical grade silicone incorporating crystal violet, methylene blue and 2 nm gold nanoparticles. Furthermore, a migration assay demonstrated that in the presence of light, growth of the fungus-like organism Pythium ultimum and the filamentous fungus Botrytis cinerea was inhibited...
November 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29120765/rapid-and-sensitive-detection-of-pyrimethanil-residues-on-pome-fruits-by-surface-enhanced-raman-scattering
#4
L Mandrile, A M Giovannozzi, F Durbiano, G Martra, A M Rossi
Surface Enhanced Raman Scattering (SERS) supported by gold nanoparticles (AuNPs) was applied to detect and quantify residues of pyrimethanil on pome fruits, a widely used fungicide in horticultural species. Spheroidal AuNPs with different size were fabricated and compared in this study. The analytical procedure was set up on a silicon dioxide flat substrate to standardize SERS methodology. A Raman mapping strategy was exploited to increase signal reproducibility and to minimize bias due to different local surface morphologies...
April 1, 2018: Food Chemistry
https://www.readbyqxmd.com/read/29120464/insight-on-the-silver-catalyst-distribution-during-silicon-nanowire-array-formation-an-x-ray-reflectivity-study
#5
Jesse W Kremenak, Christopher J Arendse, Franscious R Cummings, Yiyao Chen, Paul F Miceli
Although metal-catalysts are commonly used to create nanoscale materials at surfaces, little is quantitatively known or understood about the depth distribution profile of the catalyst during the growth process. Using X-ray reflectivity, we report the first quantitative investigation, with nanoscale resolution, of the Ag metal-catalyst depth distribution profile during metal-assisted chemical etch (MACE) growth of Si nanowire (SiNW) arrays on Si(100). Given the very low optical reflectivity of these nanowire arrays, specular reflection from these materials in the X-ray region is extremely challenging to measure because it probes interfaces on the nanoscale...
November 9, 2017: Nanoscale
https://www.readbyqxmd.com/read/29120163/tunable-synthesis-of-yolk-shell-porous-silicon-carbon-for-optimizing-si-c-based-anode-of-lithium-ion-batteries
#6
Sichang Guo, Xiang Hu, Yang Hou, Zhenhai Wen
Significant "breathing effect" calls for exploring efficient strategies to address the intrinsic issues of silicon anode of lithium ion batteries (LIBs). We here report a controllable synthetic route to fabricate the silicon-carbon hybrids, in which porous silicon nanoparticles (p-SiNPs) are loaded in void carbon spheres with forming the yolk-shell p-SiNPs@HC nanohybrids tunable. A set of controlled experiments accompanying with systematic characterizations demonstrate that the void space and mass loading of Si can be adjusted in an effective way, so that the nanostructure can be optimized with achieving improved electrochemical performance as anode of Lithium ion batteries (LIBs)...
November 9, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29117438/metallic-nano-composite-toxicity-evaluation-by-zebrafish-embryo-toxicity-test-with-identification-of-specific-exposure-biomarkers
#7
Roberta Pecoraro, Antonio Salvaggio, Fabio Marino, Gianfranco Di Caro, Fabiano Capparucci, Bianca Maria Lombardo, Giuseppina Messina, Elena Maria Scalisi, Maurizio Tummino, Francesco Loreto, Giusi D'Amante, Roberto Avola, Daniele Tibullo, Maria Violetta Brundo
Nanomaterials (NM) have different shapes and can be composed of different materials such as carbon, silicon, and some metals like gold, silver, and titanium. They are used as fillers, catalysts, semiconductors, cosmetics, drug carriers in medicine, energy storage systems, and antifriction coatings. NM are the parent compounds of nanoparticles (NPs), which may be divided into two groups: fullerenes and engineered nanoparticles (ENPs). After crossing the cell membrane, NPs may be stored in vesicles, mitochondria, and additional organelles within epithelial cells...
November 8, 2017: Current Protocols in Toxicology
https://www.readbyqxmd.com/read/29115613/preparation-of-chitosan%C3%A2-silicon-dioxide-bcsg1%C3%A2-sirna-nanoparticles-to-enhance-therapeutic-efficacy-in-breast-cancer-cells
#8
Lan Cui, Ruifeng Zheng, Wentao Liu, Peihong Shen, Youcai Tang, Junbo Luo, Wei Zhang, Guocong Jia, Yongfeng Wang, Shuaihua Zhao, Qiaoting Xie, Yanwei Li
Breast cancer is one of the most serious diseases, posing threats to women's physical and mental health. Gene therapy has been gradually regarded as an important part of tumor therapeutics. In the present study, the breast cancer‑specific gene 1‑small interference RNA (BCSG1‑siRNA) plasmid was designed, then encapsulated by chitosan‑silicon dioxide nanometer carriers. The results demonstrated a successful encapsulation of BCSG1‑siRNA in chitosan‑silicon dioxide nanoparticles (encapsulation efficiency exceeded 90%)...
October 26, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/29112913/multifunctional-nanocomplex-for-surface-enhanced-raman-scattering-imaging-and-near-infrared-photodynamic-antimicrobial-therapy-of-vancomycin-resistant-bacteria
#9
Zilong Zhou, Shanshan Peng, Minghao Sui, Shiguang Chen, Lishi Huang, Hui Xu, Tingting Jiang
Since vancomycin (Van)-resistant enterococci (VRE) strains first emerged as a serious threat to public health, extensive studies focused on optical imaging and antimicrobial therapy have been performed for monitoring and microbiological control. In this study, we developed silicon 2,3-naphthalocyanine dihydroxide (Nc) and Van functionalized silica-encapsulated, silver-coated gold nanoparticles (Au@AgNP@SiO2@Nc-Van) as a novel theranostic system for surface-enhanced Raman scattering (SERS) detection and antimicrobial photodynamic therapy (aPDT) of VRE strains...
November 2, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/29111678/bipolar-electrochemistry-on-a-nanopore-supported-platinum-nanoparticle-electrode
#10
Rui Hao, Yunshan Fan, Chu Han, Bo Zhang
In this Technical Note, we describe a method to fabricate nanopore-supported Pt nanoparticle electrodes and their use in bipolar electrochemistry. A Pt nanoparticle is deposited on the orifice of a solid-state nanopore inside a focused-ion beam (FIB) system. Complete blockage of the nanopore with Pt metal forms a closed bipolar nanoparticle electrode whose size and shape can be tunable in one simple step. Nanoparticle electrodes and their arrays can be prepared on different substrates such as the tip of a glass pipet, a double-barrel pipet, and a freestanding silicon nitride membrane...
November 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29111665/operando-raman-spectroscopy-and-synchrotron-x-ray-diffraction-of-lithiation-delithiation-in-silicon-nanoparticle-anodes
#11
Samuel Tardif, Ekaterina Pavlenko, Lucille Quazuguel, Maxime Boniface, Manuel Maréchal, Jean-Sébastien Micha, Laurent Gonon, Vincent Mareau, Gérard Gebel, Pascale Bayle-Guillemaud, François Rieutord, Sandrine Lyonnard
Operando Raman spectroscopy and synchrotron X-ray diffraction were combined to probe the evolution of strain in Li-ion battery anodes made of crystalline silicon nanoparticles. The internal structure of the nanoparticles during two discharge/charge cycles was evaluated by analyzing the intensity and position of Si diffraction peaks and Raman TO-LO phonons. Lithiation/delithiation of the silicon under limited capacity conditions triggers the formation of "crystalline core-amorphous shell" particles, which we evidenced as a stepwise decrease in core size, as well as sequences of compressive/tensile strain due to the stress applied by the shell...
November 9, 2017: ACS Nano
https://www.readbyqxmd.com/read/29109828/enhancement-of-dye-sensitized-solar-cells-efficiency-using-mixed-phase-tio2-nanoparticles-as-photoanode
#12
Yi-Hua Fan, Ching-Yuan Ho, Yaw-Jen Chang
Dye-sensitized solar cell (DSSC) is a potential candidate to replace conventional silicon-based solar cells because of high efficiency, cheap cost, and lower energy consumption in comparison with silicon chip manufacture. In this report, mixed-phase (anatase and rutile nanoparticles) TiO2 photoanode was synthesized to investigate material characteristics, carriers transport, and photovoltaic performance for future DSSC application. Field-emission scanning electron microscope (SEM), X-ray diffraction (XRD), photoluminescence (PL), and UV-visible spectroscopy were used to characterize mixed TiO2 particles...
2017: Scanning
https://www.readbyqxmd.com/read/29099996/size-and-surface-chemistry-tuning-of-silicon-carbide-nanoparticles
#13
Sergei Alekseev, Elena Shamatulskaya, Mykola Volvach, Svitlana Gryn, Dmytro Korytko, Igor Bezverkhyy, Viacheslav Iablokov, Vladimir Lysenko
Chemical transformations on the surface of commercially available 3C-SiC nanoparticles were studied by means of FTIR, XPS and temperature-programmed desorption mass spectrometry methods. Thermal oxidation of SiC NPs resulted in the formation of a hydroxylated SiO2 surface layer with C3Si-H and CHx groups over the SiO2/SiC interface. Controllable oxidation followed by oxide dissolution in HF or KOH solution allowed the SiC NPs size tuning from 17 to 9 nm. Oxide-free SiC surfaces, terminated by hydroxyls and C3Si-H groups, can be efficiently functionalized by alkenes under thermal or photochemical initiation...
November 3, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29099723/nano-fabrication-of-depth-varying-amorphous-silicon-crescent-shell-array-for-light-trapping
#14
Huan Yang, Ben Q Li, Xinbing Jiang, Wei Yu, Hongzhong Liu
We report a new structure of depth controllable amorphous silicon (a-Si) crescent shells array, fabricated by the SiO2 monolayer array assisted deposition of a-Si by plasma enhanced chemical vapor deposition (PECVD) and nanosphere lithography, for high-efficiency light trapping applications. The depth of the crescent shell cavity was tailored by selective etching of a-Si layer of the SiO2/a-Si core/shell nanoparticle array with a varied etching time. The morphological changes of the crescent shells were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM)...
November 3, 2017: Nanotechnology
https://www.readbyqxmd.com/read/29096368/electrochemiluminescent-competitive-immunosensor-based-on-polyethyleneimine-capped-sio2-nanomaterials-as-labels-to-release-ru-bpy-3-2-fixed-in-3d-cu-ni-oxalate-for-the-detection-of-aflatoxin-b1
#15
Yaoguang Wang, Guanhui Zhao, Xiaojian Li, Li Liu, Wei Cao, Qin Wei
In this work, a highly-efficient competitive method-based electrochemiluminescence (ECL) immunosensor was proposed based on {[Ru(bpy)3][Cu2xNi2(1-x)(ox)3]}n (Cu/Ni/Ru) as luminophor to efficiently detect aflatoxins B1 (AFB1). Cu/Ni/Ru exhibited excellent ECL behavior. While polyethyleneimine capped silicon dioxide (PEI@SiO2) could decrease the ECL performance of Cu/Ni/Ru due that PEI could destroy the structure of Cu/Ni/Ru via producing the complex between PEI and metal ions (Cu(II)/Ni(II)), inducing the release of Ru(bpy)3(2+)...
October 18, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29083915/optical-gaps-in-pristine-and-heavily-doped-silicon-nanocrystals-dft-versus-quantum-monte-carlo-benchmarks
#16
R Derian, K Tokár, B Somogyi, Á Gali, I Štich
We present a time-dependent density functional theory (TDDFT) study of the optical gaps of light-emitting nanomaterials, namely, pristine and heavily B- and P-codoped silicon crystalline nanoparticles. Twenty DFT exchange-correlation functionals sampled from the best currently available inventory such as hybrids and range-separated hybrids are benchmarked against ultra-accurate quantum Monte Carlo results on small model Si nanocrystals. Overall, the range-separated hybrids are found to perform best. The quality of the DFT gaps is correlated with the deviation from Koopmans' theorem as a possible quality guide...
November 8, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/29079028/modulating-effect-of-mgo-sio2-nanoparticles-on-immunological-and-histopathological-alterations-induced-by-aflatoxicosis-in-rats
#17
Sara S Essa, Eiman M El-Saied, Osama S El-Tawil, Manal B Mahmoud, Sahar S Abd El-Rahman
INTRODUCTION: AflatoxinB1 (AFB1) is well-known as a feed borne-hepatotoxic and immunosuppressive mycotoxin. This study was conducted to evaluate the efficacy of nanocomposite magnesium oxide and silicon oxide (MgO-SiO2) in reducing the toxic effects of AFB1on the immunity and histological alterations in liver, spleen and intestine of adult male rats. EXPERIMENTAL DESIGN: Animals were divided into a control (Gp1) and three experimental groups (Gps); Gp2 received feed contained 200 ppb AFB1, Gp3 received feed contained 200 ppb AFB1 and 0...
October 25, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/29073517/quantitative-detection-of-exosomal-microrna-extracted-from-human-blood-based-on-surface-enhanced-raman-scattering
#18
Dandan Ma, Caixia Huang, Jing Zheng, Jianru Tang, Jishan Li, Jinfeng Yang, Ronghua Yang
Since the nature of the exosomal lipid bilayer can allow miRNAs to be protected from degradation by cellular RNAses in body fluids, exosomal microRNA (miRNA) has become an ideal source of non-invasive biomarkers for the early diagnosis and prognosis. In this paper, a new surface-enhanced Raman scattering (SERS) analysis strategy combining stable SERS reporter element and duplex-specific nuclease (DSN)-assisted signal amplification for quantitative detection of exosomal miRNA extracted from human blood is proposed...
October 11, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/29072897/characterizing-nanoparticles-in-biological-matrices-tipping-points-in-agglomeration-state-and-cellular-delivery-in-vitro
#19
John W Wills, Huw D Summers, Nicole Hondow, Aishwarya Sooresh, Kenith E Meissner, Paul A White, Paul Rees, Andy Brown, Shareen H Doak
Understanding the delivered cellular dose of nanoparticles is imperative in nanomedicine and nanosafety, yet is known to be extremely complex because of multiple interactions between nanoparticles, their environment, and the cells. Here, we use 3-D reconstruction of agglomerates preserved by cryogenic snapshot sampling and imaged by electron microscopy to quantify the "bioavailable dose" that is presented at the cell surface and formed by the process of individual nanoparticle sequestration into agglomerates in the exposure media...
November 1, 2017: ACS Nano
https://www.readbyqxmd.com/read/29069545/gold-nanoparticles-on-functionalized-silicon-substrate-under-coulomb-blockade-regime-an-experimental-and-theoretical-investigation
#20
Olivier Pluchery, Louis Caillard, Philippe Dollfus, Yves J Chabal
Single charge electronics offer a way for disruptive technology in nanoelectronics. Coulomb blockade is a realistic way for controlling the electric current through a device with the accuracy of one electron. In such devices the current exhibits a step-like increase upon bias which reflects the discrete nature of the fundamental charge. We have assembled a double tunnel junction on an oxide-free silicon substrate that exhibits Coulomb staircase characteristics using gold nanoparticles (AuNPs) as Coulomb islands...
November 7, 2017: Journal of Physical Chemistry. B
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