Ionic liquid and nanoparticle hybrid systems: Emerging applications.

PubMed

He, Zhiqi; Alexandridis, Paschalis

2017-06-01

Having novel electronic and optical properties that emanate from their nano-scale dimensions, nanoparticles are central to numerous applications. Ionic liquids can confer to nanoparticle chemical protection and physicochemical property enhancement through intermolecular interactions and can consequently improve the stability and reusability of nanoparticle for various operations. With an aim to combine the novel properties of nanoparticles and ionic liquids, different structures have been generated, based on a balance of several intermolecular interactions. Such ionic liquid and nanoparticle hybrids are showing great potential in diverse applications. In this review, we first introduce various types of ionic liquid and nanoparticle hybrids, including nanoparticle colloidal dispersions in ionic liquids, ionic liquid-grafted nanoparticles, and nanoparticle-stabilized ionic liquid-based emulsions. Such hybrid materials exhibit interesting synergisms. We then highlight representative applications of ionic liquid and nanoparticle hybrids in the catalysis, electrochemistry and separations fields. Such hybrids can attain better stability and higher efficiency under a broad range of conditions. Novel and enhanced performance can be achieved in these applications by combining desired properties of ionic liquids and of nanoparticles within an appropriate hybrid nanostructure. Copyright © 2016 Elsevier B.V. All rights reserved.

Interaction of colloidal nanoparticles with cells (Conference Presentation)

NASA Astrophysics Data System (ADS)

Parak, Wolfgang J.

2017-02-01

What happens to inorganic nanoparticles (NPs), such as plasmonic gold or silver, superparamagnetic iron oxide, or fluorescent quantum dot NPs, after they have been administrated to an animal or a human being? The review discusses the integrity, biodistribution, and fate of NPs after in vivo administration. First the hybrid nature of the NPs is described, by conceptually dividing them into the inorganic NP core, an engineered surface coating around the core which comprises the ligand shell and optionally also bioconjugation, and into the corona of adsorbed biological molecules. It is shown that in vivo all of these three compounds may degrade individually and that each of them can drastically modify the life-cycle and biodistribution of the whole hetero-structure. The NPs thus may be disintegrated into different parts, of which biodistribution and fate would need to be analyzed individually. Multiple labelling and quantification strategies for such purpose will be discussed. All reviewed data indicate that in vivo NPs no longer should be considered as homogeneous entity, but should be seen as inorganic/organic/biological nano-hybrids with complex and intricately linked degradation pathways. References: M. Chanana, P. Rivera Gil, M. A. Correa-Duarte, L. M. Liz-Marzán. W. J. Parak, "Physicochemical Properties of Protein-Coated Gold Nanoparticles in Biological Fluids and Cells before and after Proteolytic Digestion", Angewandte Chemie International Edition 52, 4179-4183 (2013). W. G. Kreyling, A. M. Abdelmonem, Z. Ali, F. Alves, M. Geiser, N. Haberl, R. Hartmann, S. Hirn, K. Kantner, D. Jimenez de Aberasturi, G. Khadem-Saba, J.-M. Montenegro, J. Rejman, T. Rojo, I. Ruiz de Larramendi, R. Ufartes, A. Wenk, W. J. Parak, "In vivo integrity of polymer-coated gold nanoparticles", Nature Nanotechnology 10, 619-623 (2015).J. Clerk Maxwell, A Treatise on Electricity and Magnetism, 3rd ed., vol. 2. Oxford: Clarendon, 1892, pp.68-73.

2016 International Conference on Charged Lepton Flavor Violation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dukes, Edmond Craig

Partial support for participation for students and postdocs who wished to attend to give poster presentations at the 2016 International Conference on Charged Lepton Flavor Violation (CLFV 2016) in Charlottesville, VA.

Photothermal gold nanoparticle mediated stimulation of cardiomyocyte beating (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kalies, Stefan; Gentemann, Lara; Coffee, Michelle; Zweigerdt, Robert; Heinemann, Dag; Heisterkamp, Alexander

2017-03-01

Photothermal manipulation of cells via heating of gold nanoparticles has proven to be an efficient tool for molecular delivery into cells via cell perforation with short laser pulses. We investigated a potential extension of this technique for cell stimulation of cardiomyocytes using a 532 nm and 850 ps laser system and a surface concentration of 0.5 μg/cm2 of 200 nm gold nanoparticles. The gold nanoparticles were unspecifically attached to the cardiomyocytes after an incubation period of three hours. The laser irradiation leads to a temperature rise directly at the particles of several hundred degrees K which evokes bubble formation and membrane perforation. We examined the effect of laser based photothermal manipulation at different laser powers, with different calcium concentrations, and for a cardiomyocyte-like cell line (HL1 cells), neonatal rat cardiomyocytes and human embryonic stem cell (hESC)-derived cardiomyocytes. Fast calcium oscillations in HL1 cells were observed in the presence and absence of extracellular calcium and most pronounced in the area next to the laser spot after irradiation. Within the laser spot, in particular high laser powers led to a single rise in calcium over a time period of several seconds. These results were confirmed in stem cell-derived cardiomyocytes. In the presence of normal and high calcium concentrations, the spontaneous contraction frequency increased after laser irradiation in neonatal rat cardiomyocytes. Consequently, gold nanoparticle mediated photothermal cell manipulation via pulsed lasers may serve as a potential pacemaker-technique in regenerative approaches, next to optogenetics.

Student Support for EIPBN 2012 Conference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farrow, Reginald C

2013-01-29

The 56th International Conference on Electron, Ion and Photon Beam Technology and Nanofabrication (EIPBN), 2012, was held at the Hilton Waikoloa Resort in Waikoloa, Hawaii, May 29 - June 2, 2012. The EIPBN Conference is recognized as the foremost international meeting dedicated to lithographic science and technology and its application to micro and nanofabrication techniques. The conference brought together 483 engineers and scientists from industries and universities from all over the world to discuss recent progress and future trends. Among the emerging technologies that are within the scope of EIPBN is Nanofabrication for Energy Sources along with nanofabrication for themore » realization of low power integrated circuits. Every year, EIPBN provides financial support for students to attend the conference. The students gave oral and poster presentations of their research and many published peer reviewed articles in a special conference issue of the Journal of Vacuum Science and Technology B. The Department of Energy Office of Basic Energy Sciences partially supported 41 students from US universities with a $5,000.« less

Controlled assembly of nanoparticle structures: spherical and toroidal superlattices and nanoparticle-coated polymeric beads.

PubMed

Isojima, Tatsushi; Suh, Su Kyung; Vander Sande, John B; Hatton, T Alan

2009-07-21

The emulsion droplet solvent evaporation method has been used to prepare nanoclusters of monodisperse magnetite nanoparticles of varying morphologies depending on the temperature and rate of solvent evaporation and on the composition (solvent, presence of polymer, nanoparticle concentration, etc.) of the emulsion droplets. In the absence of a polymer, and with increasing solvent evaporation temperatures, the nanoparticles formed single- or multidomain crystalline superlattices, amorphous spherical aggregates, or toroidal clusters, as determined by the energetics and dynamics of the solvent evaporation process. When polymers that are incompatible with the nanoparticle coatings were included in the emulsion formulation, monolayer- and multilayer-coated polymer beads and partially coated Janus beads were prepared; the nanoparticles were expelled by the polymer as its concentration increased on evaporation of the solvent and accumulated on the surfaces of the beads in a well-ordered structure. The precise number of nanoparticle layers depended on the polymer/magnetic nanoparticle ratio in the oil droplet phase parent emulsion. The magnetic nanoparticle superstructures responded to the application of a modest magnetic field by forming regular chains with alignment of nonuniform structures (e.g., toroids and Janus beads) that are in accord with theoretical predictions and with observations in other systems.

A partial structural and functional rescue of a retinitis pigmentosa model with compacted DNA nanoparticles.

PubMed

Cai, Xue; Nash, Zack; Conley, Shannon M; Fliesler, Steven J; Cooper, Mark J; Naash, Muna I

2009-01-01

Previously we have shown that compacted DNA nanoparticles can drive high levels of transgene expression after subretinal injection in the mouse eye. Here we delivered compacted DNA nanoparticles containing a therapeutic gene to the retinas of a mouse model of retinitis pigmentosa. Nanoparticles containing the wild-type retinal degeneration slow (Rds) gene were injected into the subretinal space of rds(+/-) mice on postnatal day 5. Gene expression was sustained for up to four months at levels up to four times higher than in controls injected with saline or naked DNA. The nanoparticles were taken up into virtually all photoreceptors and mediated significant structural and biochemical rescue of the disease without histological or functional evidence of toxicity. Electroretinogram recordings showed that nanoparticle-mediated gene transfer restored cone function to a near-normal level in contrast to transfer of naked plasmid DNA. Rod function was also improved. These findings demonstrate that compacted DNA nanoparticles represent a viable option for development of gene-based interventions for ocular diseases and obviate major barriers commonly encountered with non-viral based therapies.

Synthesis and characterization of nanoparticles conjugated tannase and using it for enhancement of antibacterial activity of tannase produced by Serratia marcescens.

PubMed

Nsayef Muslim, D Sahira; Abbas Dham, Ziyad; J Mohammed, D Nadheer

2017-09-01

Fourteen isolates of Serratia marcescens were collected from patients suffering from septicemia. All theseisolates revealed different levels in tannase production. Tannase was partially purified from Serratia marcescens b9 by precipitation method at 70% saturation of ammonium sulfate. Au, Pt, SnO 2 and SiO 2 nanoparticles were prepared by laser ablation and examined by transmission electron microscopy (TEM), X-ray diffraction pattern and UV-Visible absorption spectroscopy. Conjugation of SiO 2 nanoparticles to tannase by feeding and pulses methods were prepared and characterized by TEM, X-ray diffraction pattern and UV-Visible spectrum. SiO 2 nanoparticles conjugated partially purified tannase by feeding showed the higher effectiveness and higher significant level against all tested UTI causing in comparison with ciprofloxacin antibiotic, SiO 2 nanoparticles alone, partially purified tannase alone and partially purified tannase by pulses. So that we can conclude that feeding method was the best method for enhancement partially purified tannase activity to maximum level thus SiO 2 nanoparticles conjugated partially purified tannase may be a useful antibacterial agent for the treatment of urinary tract infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Metal nanoparticles in DBS card materials modification

NASA Astrophysics Data System (ADS)

Metelkin, A.; Frolov, G.; Kuznetsov, D.; Kolesnikov, E.; Chuprunov, K.; Kondakov, S.; Osipov, A.; Samsonova, J.

2015-11-01

In the recent years the method of collecting and storing Dried Blood Spots (DBS) on special cellulose membrane (paper) has gained wide popularity. But possible damage of biosamples caused by microorganisms in case of their incomplete drying is a disadvantage of the method. It can be overcome by treating sample-collection membranes with colloidal solutions of metal nanoparticles, having antibacterial effect. The team studied antibacterial properties of nonwoven material samples with various coatings (alcohol sols of copper, aluminium, iron, titanium, silver and vanadium nanoparticles). Colloidal solutions of nanoparticles were obtained by means of electroerosion method with further low-temperature plasma condensation. Antibacterial activity of fiberglass and cellulose membrane samples with nanoparticle coatings was studied using B. cereus and plaque bacteria cultures. It was revealed that nanostructured coatings can suppress bacterial activity; in addition they can diffuse from the membrane surface into medium which leads to widening the areas of inhibiting testing cultures’ growth. Thus, membrane materials treatment with alcohol-sols of metal nanoparticles can be seen as promising for conferring antibacterial properties to DBS carriers.

EXTRACTING LIGNOCELLULOSE AND SYNTHESIZING SILICA NANOPARTICLES FROM RICE HUSKS

EPA Science Inventory

At the end of this project, we will have the demonstration package including lignocellulose fibers and silica nanoparticles (with microscope images), and a chart illustrating the optimized process. We will also submit a conference abstract and a journal manuscript for national...

Electrochemiluminescence detection of NADH and ethanol based on partial sulfonation of sol-gel network with gold nanoparticles.

PubMed

Deng, Liu; Zhang, Lihua; Shang, Li; Guo, Shaojun; Wen, Dan; Wang, Fuan; Dong, Shaojun

2009-03-15

We developed a stable, sensitive electrochemiluminescence (ECL) biosensor based on the synthesis of a new sol-gel material with the ion-exchange capacity sol-gel to coimmobilize the Ru(bpy)(3)(2+) and enzyme. The partial sulfonated (3-mercaptopropyl)-trimethoxysilane sol-gel (PSSG) film acted as both an ion exchanger for the immobilization of Ru(bpy)(3)(2+) and a matrix to immobilize gold nanoparticles (AuNPs). The AuNPs/PSSG/Ru(bpy)(3)(2+) film modified electrode allowed sensitive the ECL detection of NADH as low as 1 nM. Such an ability of AuNPs/PSSG/Ru(bpy)(3)(2+) film to promote the electron transfer between Ru(bpy)(3)(2+) and the electrode suggested a new, promising biocompatible platform for the development of dehydrogenase-based ECL biosensors. With alcohol dehydrogenase (ADH) as a model, we then constructed an ethanol biosensor, which had a linear range of 5 microM to 5.2 mM with a detection limit of 12nM.

Thermoelectric power factor enhancement by ionized nanoparticle scattering

NASA Astrophysics Data System (ADS)

Bahk, Je-Hyeong; Bian, Zhixi; Zebarjadi, Mona; Santhanam, Parthiban; Ram, Rajeev; Shakouri, Ali

2011-08-01

We show theoretically that the thermoelectric power factor can be enhanced in degenerate semiconductors when embedded nanoparticles donate carriers to the matrix and replace conventional impurity dopants as scattering centers. Nanoparticle scattering rates calculated by the partial wave method indicate a mobility enhancement over materials with equivalent doping by isolated ionized impurities while the Seebeck coefficient remains nearly intact. We find that the thermoelectric power factor of In0.53Ga0.47As from 300 K to 800 K is enhanced by 15% - 30% by nanoparticles 3-4 nm in diameter.

An improved, non-functionalized route to plasmonic nanoparticle based cellular probing through osmolyte mediation (Conference Presentation)

NASA Astrophysics Data System (ADS)

Siddhanta, Soumik; Barman, Ishan

2017-02-01

Engineering nanostructured probes for ultra-sensitive detection of specific molecular species, our research seeks to capture the complex changes in cells and tissues that can predict disease progression in an individual. While such nanoparticle-based platforms are rapidly gaining a foothold in cancer diagnostics, one of the most concerning factors is the vulnerability of cells to the interaction with functional nanoparticles thereby raising the specter of systemic toxicity. The nanoparticles end up damaging the cells and disrupting cellular functions thereby impeding their imaging aim. Furthermore, PEGylation, and similar routes, force a tradeoff between desired nanoparticle properties (recognition, uptake, and reduced toxicity) and sensitivity of plasmon-enhanced spectroscopic sensing methods, such as surface-enhanced Raman spectroscopy (SERS) where the proximal presence of noble metal NP and the organic molecule of interest is key. In this work, we report a trehalose-mediated, non-surface functionalized route for cell-nanoparticle interactions that maintains cell viability while allowing selective interaction of the nanoparticle with the cell surface receptors and subsequent internalization. Through careful electron microscopy of nanoparticle-prostate cancer cells interactions, we elucidated that there exists a dynamic equilibrium between "free" cytosolic diffusion of the nanoparticles and endocytosis through vesicle formation - and trehalose tilts the scale in favor of the latter to mask the toxic effects of the nanoparticles. The precise molecular interpretation of this behavior was further probed through SERS, which directly points towards the protein stabilization properties of trehalose mediation during interaction of the nanoparticles with the plasma membrane components.

Blood test using surface-enhanced Raman spectroscopy with colloidal silver nanoparticle substrate to detect polyps and colorectal cancer (Conference Presentation)

NASA Astrophysics Data System (ADS)

Wang, Wenbo; Feng, Shangyuan; Tai, Isabella T.; Chen, Guannan; Chen, Rong; Zeng, Haishan

2016-03-01

Colorectal cancer (CRC) is the third most common type of cancer and forth leading cause of cancer-related death. Early diagnosis is the key to long-term patient survival. Programmatic screening for the general population has shown to be cost-effective in reducing the incidence and mortality from CRC. Current CRC screening strategy relies on a broad range of test techniques such as fecal based tests and endoscopic exams. Occult blood tests like fecal immunochemical test is a cost effective way to detect CRC but have limited diagnostic values in detecting adenomatous polyp, the most treatable precursor to CRC. In the present work, we proposed the use of surface enhanced Raman spectroscopy (SERS) with silver nanoparticles as substrate to analyze blood plasma for detecting both CRC and adenomatous polyps. Blood plasma samples collected from healthy subjects and patients diagnosed with adenomas and CRC were prepared with nanoparticles and measured using a real-time fiber optic probe based Raman system. The collected SERS spectra are analyzed with partial least squares-discriminant analysis. Classification of normal versus CRC plus adenomatous polyps achieved diagnostic sensitivity of 86.4% and specificity of 80%. This exploratory study suggests that blood plasma SERS analysis has potential to become a screening test for detecting both CRC and adenomas.

18th International Mouse Genome Conference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lossie, Amy C.; Meehan, Thomas P.; Castillo, Andrew

2005-07-01

The 18th International Mouse Genome Conference was held in Seattle, WA, US on October 18-22,2004. The meeting was partially supported by the Department of Energy, Grant No. DE-FG02-04ER63851. Abstracts can be seen at imgs.org and the summary of the meeting was published in Mammalian Genome, Vol 16, Number 7, Pages 471-475.

High-throughput nanoparticle sizing using lensfree holographic microscopy and liquid nanolenses (Conference Presentation)

NASA Astrophysics Data System (ADS)

McLeod, Euan

2016-03-01

The sizing of individual nanoparticles and the recovery of the distributions of sizes from populations of nanoparticles provide valuable information in virology, exosome analysis, air and water quality monitoring, and nanomaterials synthesis. Conventional approaches for nanoparticle sizing include those based on costly or low-throughput laboratory-scale equipment such as transmission electron microscopy or nanoparticle tracking analysis, as well as those approaches that only provide population-averaged quantities, such as dynamic light scattering. Some of these limitations can be overcome using a new family of alternative approaches based on quantitative phase imaging that combines lensfree holographic on-chip microscopy with self-assembled liquid nanolenses. In these approaches, the particles of interest are deposited onto a glass coverslip and the sample is coated with either pure liquid polyethylene glycol (PEG) or aqueous solutions of PEG. Due to surface tension, the PEG self-assembles into nano-scale lenses around the particles of interest. These nanolenses enhance the scattering signatures of the embedded particles such that individual nanoparticles as small as 40 nm are clearly visible in phase images reconstructed from captured holograms. The magnitude of the phase quantitatively corresponds to particle size with an accuracy of +/-11 nm. This family of approaches can individually size more than 10^5 particles in parallel, can handle a large dynamic range of particle sizes (40 nm - 100s of microns), and can accurately size multi-modal distributions of particles. Furthermore, the entire approach has been implemented in a compact and cost-effective device suitable for use in the field or in low-resource settings.

PREFACE: 8th International Conference on Fine Particle Magnetism (ICFPM2013)

NASA Astrophysics Data System (ADS)

2014-06-01

The 8th International Conference on Fine Particle Magnetism (ICFPM) was held in Perpignan from 24 to 27 June 2013, and was the continuation of the previous meetings held in Bangor (1996), Rome (1991), Barcelona (1999), Pittsburg (2002), London (2004), Rome (2007) and Uppsala (2010). The next meeting will be organized by Profs. Robert D. Shull, George Hadjipanayis and Cindi Dennis, in 2016 at NIST, Gaithersburg (USA). ICFPM is a small-sized conference focused on the magnetism of nanoparticles. It provides an international forum for discussing the state-of-the-art understanding of physics of these systems, of their properties and the underlying phenomena, as approached from a variety of directions: theory and modelling, experiments on well characterized or model systems (both fabricated and synthetised), as well as experiments on technologically-relevant non-ideal systems. This meeting brought together about 120 participants working on experimental, theoretical and applied topics of the multidisciplinary research areas covered by magnetic nanoparticles, with focused interest on either single-particle or collective phenomena. The technical program of the conference was based on keynote conferences, invited talks, oral contributions and poster sessions, covering the following aspects: . Fabrication, synthesis, characterization . Single particle, surface and finite-size effects on magnetic properties . Magnetization dynamics, micro-wave assisted switching, dynamical coupling . Assemblies, collective effects, self-assembling and nanostructuring . Applications : hyperthermia, drug delivery, magneto-caloric, magneto-resistance, magneto-plasmonics, magnetic particle imaging This ICFPM edition was organized by the group Nanoscale Spin Systems of the laboratory PROMES of the CNRS (UPR8521), and Université de Perpignan Via Domitia. The meeting took place at the Congress Center of the city of Perpignan providing high-quality facilities for the technical program as well for the

The biomolecular corona is retained during nanoparticle uptake and protects the cells from the damage induced by cationic nanoparticles until degraded in the lysosomes.

PubMed

Wang, Fengjuan; Yu, Lu; Monopoli, Marco P; Sandin, Peter; Mahon, Eugene; Salvati, Anna; Dawson, Kenneth A

2013-11-01

Nanoparticles have unique capacities of interacting with the cellular machinery and entering cells. To be able to exploit this potential, it is essential to understand what controls the interactions at the interface between nanoparticles and cells: it is now established that nanoparticles in biological media are covered by proteins and other biomolecules forming a "corona" on the nanoparticle surface, which confers a new identity to the nanoparticles. By labelling the proteins of the serum, using positively-charged polystyrene, we now show that this adsorbed layer is strong enough to be retained on the nanoparticles as they enter cells and is trafficked to the lysosomes on the nanoparticles. There, the corona is degraded and this is followed by lysosomal damage, leading to cytosolic release of lysosomal content, and ultimately apoptosis. Thus the corona protects the cells from the damage induced by the bare nanoparticle surface until enzymatically cleared in the lysosomes. This study investigates the effects of protein corona that normally forms on the surface of nanoparticles during in vivo use, describing the steps of intracellular processing of such particles, to enhance our understanding of how these particles interact with the cellular machinery. Copyright © 2013 Elsevier Inc. All rights reserved.

Probing the effect of charge transfer enhancement in off resonance mode SERS via conjugation of the probe dye between silver nanoparticles and metal substrates.

PubMed

Selvakannan, Pr; Ramanathan, Rajesh; Plowman, Blake J; Sabri, Ylias M; Daima, Hemant K; O'Mullane, Anthony P; Bansal, Vipul; Bhargava, Suresh K

2013-08-21

The charge transfer-mediated surface enhanced Raman scattering (SERS) of crystal violet (CV) molecules that were chemically conjugated between partially polarized silver nanoparticles and optically smooth gold and silver substrates has been studied under off-resonant conditions. Tyrosine molecules were used as a reducing agent to convert silver ions into silver nanoparticles where oxidised tyrosine caps the silver nanoparticle surface with its semiquinone group. This binding through the quinone group facilitates charge transfer and results in partially oxidised silver. This establishes a chemical link between the silver nanoparticles and the CV molecules, where the positively charged central carbon of CV molecules can bind to the terminal carboxylate anion of the oxidised tyrosine molecules. After drop casting Ag nanoparticles bound with CV molecules it was found that the free terminal amine groups tend to bind with the underlying substrates. Significantly, only those CV molecules that were chemically conjugated between the partially polarised silver nanoparticles and the underlying gold or silver substrates were found to show SERS under off-resonant conditions. The importance of partial charge transfer at the nanoparticle/capping agent interface and the resultant conjugation of CV molecules to off resonant SERS effects was confirmed by using gold nanoparticles prepared in a similar manner. In this case the capping agent binds to the nanoparticle through the amine group which does not facilitate charge transfer from the gold nanoparticle and under these conditions SERS enhancement in the sandwich configuration was not observed.

Interferometric detection of nanoparticles

NASA Astrophysics Data System (ADS)

Hayrapetyan, Karen

Interferometric surfaces enhance light scattering from nanoparticles through constructive interference of partial scattered waves. By placing the nanoparticles on interferometric surfaces tuned to a special surface phase interferometric condition, the particles are detectable in the dilute limit through interferometric image contrast in a heterodyne light scattering configuration, or through diffraction in a homodyne scattering configuration. The interferometric enhancement has applications for imaging and diffractive biosensors. We present a modified model based on Double Interaction (DI) to explore bead-based detection mechanisms using imaging, scanning and diffraction. The application goal of this work is to explore the trade-offs between the sensitivity and throughput among various detection methods. Experimentally we use thermal oxide on silicon to establish and control surface interferometric conditions. Surface-captured gold beads are detected using Molecular Interferometric Imaging (MI2) and Spinning-Disc Interferometry (SDI). Double-resonant enhancement of light scattering leads to high-contrast detection of 100 nm radius gold nanoparticles on an interferometric surface. The double-resonance condition is achieved when resonance (or anti-resonance) from an asymmetric Fabry-Perot substrate coincides with the Mie resonance of the gold nanoparticle. The double-resonance condition is observed experimentally using molecular interferometric imaging (MI2). An invisibility condition is identified for which the gold nanoparticles are optically cloaked by the interferometric surface.

Resveratrol-loaded glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles: Preparation, characterization, and targeting effect on liver tumors.

PubMed

Wu, Mingfang; Lian, Bolin; Deng, Yiping; Feng, Ziqi; Zhong, Chen; Wu, Weiwei; Huang, Yannian; Wang, Lingling; Zu, Chang; Zhao, Xiuhua

2017-08-01

In this study, glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles were prepared to establish a tumor targeting nano-sized drug delivery system. Glycyrrhizic acid was coupled to human serum albumin, and resveratrol was encapsulated in glycyrrhizic acid-conjugated human serum albumin by high-pressure homogenization emulsification. The average particle size of sample nanoparticles prepared under the optimal conditions was 108.1 ± 5.3 nm with a polydispersity index (PDI) of 0.001, and the amount of glycyrrhizic acid coupled with human serum albumin was 112.56 µg/mg. The drug encapsulation efficiency and drug loading efficiency were 83.6 and 11.5%, respectively. The glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles were characterized through laser light scattering, scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, thermogravimetric analyses, and gas chromatography. The characterization results showed that resveratrol in glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles existed in amorphous state and the residual amounts of chloroform and methanol in nanoparticles were separately less than the international conference on harmonization (ICH) limit. The in vitro drug-release study showed that the nanoparticles released the drug slowly and continuously. The inhibitory rate of glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide method. The IC50 values of glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles and resveratrol were 62.5 and 95.5 µg/ml, respectively. The target ability of glycyrrhizic acid-conjugated human serum albumin nanoparticles wrapping resveratrol nanoparticles

Direct visualization of nanoparticle dynamics at liquid interfaces

NASA Astrophysics Data System (ADS)

Gao, Yige; Kim, Paul; Hoagland, David; Russell, Tom

Ionic liquids, because of their negligible vapor pressures and moderate viscosities, are suitable media to investigate the dynamics of different types of dispersed nanoparticles by scanning electron microscopy. No liquid cell is necessary. Here, Brownian motions of nanoparticles partially wetted at the vacuum-liquid interface are visualized by low voltage SEM under conditions that allow single particle tracking for tens-of-minutes or longer. Conductive, nonconductive, semiconductive, and core-shell conductive-nonconductive nanoparticles have all been studied, and their interactions with each other in one- and two-component layers, as manifested in particle trajectories, differ significantly. For example, Au-coated silica nanoparticles aggregate above a threshold current, whereas aggregated silica-coated Au nanoparticles disaggregate at the same conditions. The impacts of surface concentration of nanoparticle dynamics were observed for one-component and two-component layers, with both global and localized motions visualized for single particles even in dense environments. As the surface concentration increases, the diffusion coefficient drops, and when the concentration reaches a critical threshold, the nanoparticles are essentially frozen. Financial support from NSF DMR-1619651 is acknowledged.

Biogenic nanoparticles bearing antibacterial activity and their synergistic effect with broad spectrum antibiotics: Emerging strategy to combat drug resistant pathogens.

PubMed

Baker, Syed; Pasha, Azmath; Satish, Sreedharamurthy

2017-01-01

The present study emphasizes on synthesis of bimetallic silver-gold nanoparticles from cell free supernatant of Pseudomonas veronii strain AS41G inhabiting Annona squamosa L. The synthesized nanoparticles were characterized using hyphenated techniques with UV-Visible spectra ascertained absorbance peak between 400 and 800 nm. Possible interaction of biomolecules in mediating and stabilization of nanoparticles was depicted with Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) displayed Bragg's peak conferring the 1 0 0, 1 1 1, 2 0 0, and 2 2 0 facets of the face centered cubic symmetry of nanoparticles suggesting that these nanoparticles were crystalline in nature. Size and shape of the nanoparticles were determined using Transmission electron microscopy (TEM) microgram with size ranging from 5 to 50 nm forming myriad shapes. Antibacterial activity of nanoparticles against significant human pathogens was conferred with well diffusion assay and its synergistic effect with standard antibiotics revealed 87.5% fold increased activity with antibiotic "bacitracin" against bacitracin resistant strains Bacillus subtilis , Escherichia coli and Klebsiella pneumoniae followed by kanamycin with 18.5%, gentamicin with 11.15%, streptomycin with 10%, erythromycin with 9.7% and chloramphenicol with 9.4%. Thus the study concludes with biogenic and ecofriendly route for synthesizing nanoparticles with antibacterial activity against drug resistant pathogens and attributes growing interest on endophytes as an emerging source for synthesis of nanoparticles.

Core-Shell Photonic Nanoparticles for Enhanced Solar-to-Fuel Photocatalytic Conversion

DTIC Science & Technology

2017-10-11

photocatalytic activity of semiconducting materials. They synthesized and functionalized titanium dioxide nanoparticles with a partial shell of gold...Their research also characterized the photocatalytic activity . The second area was the tuning the dielectric environment of the nanoparticles with think...successful investigation of bimetallic nanoshells that enhance the photocatalytic activity of semiconducting materials. Our earlier work focused on the

Enrichment of plasma membrane proteins using nanoparticle pellicles: comparison between silica and higher density nanoparticles

PubMed Central

Choksawangkarn, Waeowalee; Kim, Sung-Kyoung; Cannon, Joe R.; Edwards, Nathan J.; Lee, Sang Bok; Fenselau, Catherine

2013-01-01

Proteomic and other characterization of plasma membrane proteins is made difficult by their low abundance, hydrophobicity, frequent carboxylation and dynamic population. We and others have proposed that underrepresentation in LC-MS/MS analysis can be partially compensated by enriching the plasma membrane and its proteins using cationic nanoparticle pellicles. The nanoparticles increase the density of plasma membrane sheets and thus enhance separation by centrifugation from other lysed cellular components. Herein we test the hypothesis that the use of nanoparticles with increased densities can provide enhanced enrichment of plasma membrane proteins for proteomic analysis. Multiple myeloma cells were grown and coated in suspension with three different pellicles of three different densities and both pellicle coated and uncoated suspensions analyzed by high-throughput LC-MS/MS. Enrichment was evaluated by the total number and the spectral counts of identified plasma membrane proteins. PMID:23289353

Identification of BRCA1 missense substitutions that confer partial functional activity: potential moderate risk variants?

PubMed

Lovelock, Paul K; Spurdle, Amanda B; Mok, Myth T S; Farrugia, Daniel J; Lakhani, Sunil R; Healey, Sue; Arnold, Stephen; Buchanan, Daniel; Couch, Fergus J; Henderson, Beric R; Goldgar, David E; Tavtigian, Sean V; Chenevix-Trench, Georgia; Brown, Melissa A

2007-01-01

functional studies to be performed in order to identify variants with partially compromised function. The results also raise the possibility that A1708V and R1699Q may be associated with a low or moderate risk of cancer. While data pooling strategies may provide more information for multifactorial analysis to improve the interpretation of the clinical significance of these variants, it is likely that the development of current multifactorial likelihood approaches and the consideration of alternative statistical approaches will be needed to determine whether these individually rare variants do confer a low or moderate risk of breast cancer.

Identification of BRCA1 missense substitutions that confer partial functional activity: potential moderate risk variants?

PubMed Central

Lovelock, Paul K; Spurdle, Amanda B; Mok, Myth TS; Farrugia, Daniel J; Lakhani, Sunil R; Healey, Sue; Arnold, Stephen; Buchanan, Daniel; Investigators, kConFab; Couch, Fergus J; Henderson, Beric R; Goldgar, David E; Tavtigian, Sean V; Chenevix-Trench, Georgia; Brown, Melissa A

2007-01-01

These data highlight the need for a range of functional studies to be performed in order to identify variants with partially compromised function. The results also raise the possibility that A1708V and R1699Q may be associated with a low or moderate risk of cancer. While data pooling strategies may provide more information for multifactorial analysis to improve the interpretation of the clinical significance of these variants, it is likely that the development of current multifactorial likelihood approaches and the consideration of alternative statistical approaches will be needed to determine whether these individually rare variants do confer a low or moderate risk of breast cancer. PMID:18036263

PREFACE: 5th Baltic Conference on Silicate Materials

NASA Astrophysics Data System (ADS)

Mezinskis, G.; Bragina, L.; Colombo, P.; Frischat, G. H.; Grabis, J.; Greil, P.; Deja, J.; Kaminskas, R.; Kliava, J.; Medvids, A.; Nowak, I.; Siauciunas, R.; Valancius, Z.; Zalite, I.

2011-12-01

Logo This Volume of IOP Conference Series: Materials Science and Engineering presents a selection of the contributions to the 5th Baltic Conference on Silicate Materials (BaltSilica2011) held at Riga Technical University, Riga, Latvia from 23-25 May 2011. The conference was organized by Riga Technical University (Latvia) and Kaunas University of Technology (Lithuania). The series of Baltic conferences on silicate materials was started since 2004: the first conference was held in Riga, Latvia, 2004; the second conference was held in Kaunas, Lithuania 2005; the third was held again in Riga, Latvia, 2007, and the fourth was held in Kaunas, Lithuania 2009. BaltSilica 2011 was attended by around 50 participants from Latvia, Lithuania, Estonia, Germany, Poland, Italy, France, Ukraine and Russia. In comparison with previous silicate materials conferences, the broadening of participating countries is an indication of the interest of scientists, engineers and students to exchange research ideas, latest results, and to find new research topics for cooperation in the fields of silicate, high temperature materials, and inorganic nanomaterials. The scientific programme included 8 invited plenary lectures 23 oral presentations and 25 posters [1]. Scientific themes covered in the conference and in this special issue: Natural and Artificial Stone Materials; Traditional and New Ceramic and Glass-Like Materials; Nanoparticles and Nanomaterials. This volume consists of 23 selected proceeding papers. The Editor of this special issue is grateful to all the contributors to BaltSilica 2011. I am also very grateful to the scientific committee, the local organizing committee, the session chairs, the referees who refereed the submitted articles to this issue, and to students from the Department of Silicate, High Temperature and Inorganic Nanomaterials Technology of the Riga Technical University who ensured the smooth running of the conference. Particular thanks goes to eight plenary

Multimodal imaging of lymph nodes and tumors using glycol-chitosan-coated gold nanoparticles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sun, In-Cheol; Dumani, Diego S.; Emelianov, Stanislav Y.

2017-03-01

A key step in staging cancer is the diagnosis of metastasis that spreads through lymphatic system. For this reason, researchers develop various methods of sentinel lymph node mapping that often use a radioactive tracer. This study introduces a safe, cost-effective, high-resolution, high-sensitivity, and real-time method of visualizing the sentinel lymph node: ultrasound-guided photoacoustic (US/PA) imaging augmented by a contrast agent. In this work, we use clearable gold nanoparticles covered by a biocompatible polymer (glycol chitosan) to enhance cellular uptake by macrophages abundant in lymph nodes. We incubate macrophages with glycol-chitosan-coated gold nanoparticles (0.05 mg Au/ml), and then fix them with paraformaldehyde solution for an analysis of in vitro dark-field microscopy and cell phantom. The analysis shows enhanced cellular uptake of nanoparticles by macrophages and strong photoacoustic signal from labeled cells in tissue-mimicking cell phantoms consisting gelatin solution (6 %) with silica gel (25 μm, 0.3%) and fixed macrophages. The in-vivo US/PA imaging of cervical lymph nodes in healthy mice (nu/nu, female, 5 weeks) indicates a strong photoacoustic signal from a lymph node 10 minutes post-injection (2.5 mg Au/ml, 80 μl). The signal intensity and the nanoparticle-labeled volume of tissue within the lymph node continues to increase until 4 h post-injection. Histological analysis further confirms the accumulation of gold nanoparticles within the lymph nodes. This work suggests the feasibility of molecular/cellular US/PA imaging with biocompatible gold nanoparticles as a photoacoustic contrast agent in the diagnosis of lymph-node-related diseases.

Sonochemical Synthesis of Silver Nanoparticles Using Starch: A Comparison

PubMed Central

Smita, Kumari; Cumbal, Luis; Debut, Alexis; Pathak, Ravinandan Nath

2014-01-01

A novel approach was applied to synthesize silver nanoparticles using starch under sonication. Colloidal silver nanoparticles solution exhibited an increase of absorption from 420 to 440 nm with increase starch quantity. Transmission electron microscopy followed by selected area electron diffraction pattern analysis indicated the formation of spherical, polydispersed, amorphous, silver nanoparticles of diameter ranging from 23 to 97 nm with mean particle size of 45.6 nm. Selected area electron diffraction (SAED) confirmed partial crystalline and amorphous nature of silver nanoparticles. Silver nanoparticles synthesized in this manner can be used for synthesis of 2-aryl substituted benzimidazoles which have numerous biomedical applications. The optimized reaction conditions include 10 ml of 1 mM AgNO3, 25 mg starch, 11 pH range, and sonication for 20 min at room temperature. PMID:24587771

Spherically-clustered porous Au-Ag alloy nanoparticle prepared by partial inhibition of galvanic replacement and its application for efficient multimodal therapy.

PubMed

Jang, Hongje; Min, Dal-Hee

2015-03-24

The polyvinylpyrrolidone (PVP)-coated spherically clustered porous gold-silver alloy nanoparticle (PVP-SPAN) was prepared by low temperature mediated, partially inhibited galvanic replacement reaction followed by silver etching process. The prepared porous nanostructures exhibited excellent photothermal conversion efficiency under irradiation of near-infrared light (NIR) and allowed a high payload of both doxorubicin (Dox) and thiolated dye-labeled oligonucleotide, DNAzyme (FDz). Especially, PVP-SPAN provided 10 times higher loading capacity for oligonucleotide than conventional hollow nanoshells due to increased pore diameter and surface-to-volume ratio. We demonstrated highly efficient chemo-thermo-gene multitherapy based on codelivery of Dox and FDz with NIR-mediated photothermal therapeutic effect using a model system of hepatitis C virus infected human liver cells (Huh7 human hepatocarcinoma cell line containing hepatitis C virus NS3 gene replicon) compared to conventional hollow nanoshells.

Molecular Quantum Mechanics 2010: From Methylene to DNA and Beyond Conference Support

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

This grant was $12500 for partial support of an international conference, Molecular Quantum Mechanics 2010, which was held on the campus of the University of California, Berkeley, from 24 to 29 May 2010. The conference involved more than 250 participants. The conference schedule ran from as early as 8:00 AM to as late as 10:30 PM at night, in order to accommodate six historical lectures, 16 plenary lectures, 42 invited talks and two very strong poster sessions containing 143 contributed posters. Since 1989, the Molecular Quantum Mechanics (MQM) series of international conferences has show- cased the frontiers of research inmore » quantum chemistry with a strong focus on basic theory and algorithms, as well as highlights of topical applications. Both were strongly in evidence at MQM 2010. At the same time as embracing the future, the MQM conferences also honour the lifetime contributions of some of the most prominent scientists in the field of theoretical and computational quantum chemistry. MQM 2010 recognised the work of Prof. Henry F. ‘Fritz’ Schaefer of the Center for Computational Chemistry at the University of Georgia, who was previously on the faculty at Berkeley The travel of invited speakers was partially covered by sponsorships from Dell Computer, Hewlett-Packard, Journal of Chemical Theory and Computation, Virginia Tech College of Science, Molecular Physics, Q-Chem Inc and the American Institute of Physics. By contrast, the conference grant from the Department of Energy was used to provide fellowships and scholarships to enable graduate students and postdoctoral fellows to attend the meeting, and thereby broaden the participation of young scientists at a meeting where in the past most of the attendees have been more senior faculty researchers. We believe that we were very successful in this regard: 118 students and postdocs attended out of the total of 256 participants. In detail, the DOE sponsorship money was partially used for dormitory

Ordered CdSe nanoparticles within self-assembled block copolymer domains on surfaces.

PubMed

Zou, Shan; Hong, Rui; Emrick, Todd; Walker, Gilbert C

2007-02-13

Hierarchical, high-density, ordered patterns were fabricated on Si substrates by self-assembly of CdSe nanoparticles within approximately 20-nm-thick diblock copolymer films in a controlled manner. Surface-modified CdSe nanoparticles formed well-defined structures within microphase-separated polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) domains. Trioctylphosphine oxide (TOPO)-coated CdSe nanoparticles were incorporated into PS domains and polyethylene glycol-coated CdSe nanoparticles were located primarily in the P2VP domains. Nearly close-packed CdSe nanoparticles were clearly identified within the highly ordered patterns on Si substrates by scanning electron microscopy (SEM). Contact angle measurements together with SEM results indicate that TOPO-CdSe nanoparticles were partially placed at the air/copolymer interface.

To Moscow with love: partial reconstruction of Vygotsky's trip to London.

PubMed

van der Veer, René; Zavershneva, Ekaterina

2011-12-01

The Russian psychologist Lev Vygotsky (1896-1934) left the Soviet Union only once to attend a conference on the education of the deaf in London. So far almost nothing was known about this trip, which took place in a period when Vygotsky was still completely unknown as a psychologist, both inside his own country and abroad. Making use of a newly discovered notebook, it proved possible to partially reconstruct Vygotsky's journey and stay in London. Vygotsky's very personal remarks show him to have been a very sensitive and spirited man, who was prey to strong emotions during the conference and afterwards. Rather surprisingly, Vygotsky's own paper about the education of the deaf was never presented during the conference and the stay in London appears to have had a limited value for his own scientific development.

Support for the 38th International Conference on High Energy Physics, 3-10 August 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Young-Kee

The 38th International Conference on High Energy Physics (ICHEP) held in Chicago from August 3 to 10, 2016 was for physicists from around the world to gather to share the latest advancements in particle physics, astrophysics/cosmology, and accelerator science and to discuss plans for major future facilities. DOE funding provided partial support for space rental audio-visual services for scientific presentations at the conference.

Pulsed Laser Synthesized Magnetic Cobalt Oxide Nanoparticles for Biomedical Applications

NASA Astrophysics Data System (ADS)

Bhatta, Hari; Gupta, Ram; Ghosh, Kartik; Kahol, Pawan; Delong, Robert; Wanekawa, Adam

2011-03-01

Nanomaterials research has become a major attraction in the field of advanced materials research in the area of Physics, Chemistry, and Materials Science. Biocompatible and chemically stable magnetic metal oxide nanoparticles have biomedical applications that includes drug delivery, cell and DNA separation, gene cloning, magnetic resonance imaging (MRI). This research is aimed at the fabrication of magnetic cobalt oxide nanoparticles using a safe, cost effective, and easy to handle technique that is capable of producing nanoparticles free of any contamination. Cobalt oxide nanoparticles have been synthesized at room temperature using cobalt foil by pulsed laser ablation technique. These cobalt oxide nanoparticles were characterized using UV-Visible (UV-Vis) spectroscopy, transmission electron microscopy (TEM), and dynamic laser light scattering (DLLS). The magnetic cobalt oxides nanoparticles were stabilized in glucose solutions of various concentrations in deionized water. The presence of UV-Vis absorption peak at 270 nm validates the nature of cobalt oxide nanoparticles. The DLLS size distributions of nanoparticles are in the range of 110 to 300 nm, which further confirms the presence nanoparticles. This work is partially supported by National Science Foundation (DMR- 0907037).

Synthesis of surface bound silver nanoparticles on cellulose fibers using lignin as multi-functional agent.

PubMed

Hu, Sixiao; Hsieh, You-Lo

2015-10-20

Lignin has proven to be highly effective "green" multi-functional binding, complexing and reducing agents for silver cations as well as capping agents for the synthesis of silver nanoparticles on ultra-fine cellulose fibrous membranes. Silver nanoparticles could be synthesized in 10min to be densely distributed and stably bound on the cellulose fiber surfaces at up to 2.9% in mass. Silver nanoparticle increased in sizes from 5 to 100nm and became more polydispersed in size distribution on larger fibers and with longer synthesis time. These cellulose fiber bound silver nanoparticles did not agglomerate under elevated temperatures and showed improved thermal stability. The presence of alkali lignin conferred moderate UV absorbing ability in both UV-B and UV-C regions whereas the bound silver nanoparticles exhibited excellent antibacterial activities toward Escherichia coli. Copyright © 2015 Elsevier Ltd. All rights reserved.

Current understanding of interactions between nanoparticles and the immune system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dobrovolskaia, Marina A., E-mail: marina@mail.nih.

2016-05-15

The delivery of drugs, antigens, and imaging agents benefits from using nanotechnology-based carriers. The successful translation of nanoformulations to the clinic involves thorough assessment of their safety profiles, which, among other end-points, includes evaluation of immunotoxicity. The past decade of research focusing on nanoparticle interaction with the immune system has been fruitful in terms of understanding the basics of nanoparticle immunocompatibility, developing a bioanalytical infrastructure to screen for nanoparticle-mediated immune reactions, beginning to uncover the mechanisms of nanoparticle immunotoxicity, and utilizing current knowledge about the structure–activity relationship between nanoparticles' physicochemical properties and their effects on the immune system to guidemore » safe drug delivery. In the present review, we focus on the most prominent pieces of the nanoparticle–immune system puzzle and discuss the achievements, disappointments, and lessons learned over the past 15 years of research on the immunotoxicity of engineered nanomaterials. - Graphical abstract: API — active pharmaceutical ingredient; NP — nanoparticles; PCP — physicochemical properties, CARPA — complement activation-related pseudoallergy, ICH — International Conference on Harmonization. Display Omitted - Highlights: • Achievements, disappointments and lessons learned over past decade are reviewed. • Areas in focus include characterization, immunotoxicity and utility in drug delivery. • Future direction focusing on mechanistic immunotoxicity studies is proposed.« less

An interdisciplinary computational/experimental approach to evaluate drug-loaded gold nanoparticle tumor cytotoxicity

PubMed Central

Curtis, Louis T; England, Christopher G; Wu, Min; Lowengrub, John; Frieboes, Hermann B

2016-01-01

Aim: Clinical translation of cancer nanotherapy has largely failed due to the infeasibility of optimizing the complex interaction of nano/drug/tumor/patient parameters. We develop an interdisciplinary approach modeling diffusive transport of drug-loaded gold nanoparticles in heterogeneously-vascularized tumors. Materials & methods: Evaluated lung cancer cytotoxicity to paclitaxel/cisplatin using novel two-layer (hexadecanethiol/phosphatidylcholine) and three-layer (with high-density-lipoprotein) nanoparticles. Computer simulations calibrated to in-vitro data simulated nanotherapy of heterogeneously-vascularized tumors. Results: Evaluation of free-drug cytotoxicity between monolayer/spheroid cultures demonstrates a substantial differential, with increased resistance conferred by diffusive transport. Nanoparticles had significantly higher efficacy than free-drug. Simulations of nanotherapy demonstrate 9.5% (cisplatin) and 41.3% (paclitaxel) tumor radius decrease. Conclusion: Interdisciplinary approach evaluating gold nanoparticle cytotoxicity and diffusive transport may provide insight into cancer nanotherapy. PMID:26829163

TiO2 nanoparticles alleviate toxicity by reducing free Zn2+ ion in human primary epidermal keratinocytes exposed to ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Kathawala, Mustafa Hussain; Ng, Kee Woei; Loo, Say Chye Joachim

2015-06-01

Nanoparticles have been a subject of intense safety screenings due to their influx in various applications. Although recent studies have reported on the plausible cytotoxicity of nanoparticles, many of these focused only on single-material nanoparticles, while the cytotoxicity of dual-nanoparticle systems (e.g., ZnO with TiO2) has remained unexplored. For example, commercial products like sunscreens and cosmetics contain both nano-sized ZnO and TiO2, but cytotoxicity studies of such systems are meager. In this paper, the cytotoxicity of this dual-nanoparticle system comprising both ZnO and TiO2 was evaluated in vitro on skin-mimicking human primary epidermal keratinocytes (HPEKs). Inductively coupled plasma mass spectrometry, flow cytometry, and confocal microscopy were used to investigate the uptake of nanoparticles and free ions. Results revealed that ZnO nanoparticles were partially soluble (up to 20 μg ml-1 after 1 day) and could induce strong cytotoxicity as compared to the insoluble TiO2 nanoparticles which remained non-toxic until very high concentrations. It was found that TiO2 nanoparticles could play "vigilante" by protecting keratinocytes from acute toxicity of ZnO nanoparticles. This is in agreement with the observation that TiO2 nanoparticles caused an attenuation of free intracellular Zn2+ ions concentration, by adsorbing and immobilizing free Zn2+ ions. This study reveals a unique dual-nanoparticle observation in vitro on HPEKs, and highlights the importance of dual-nanoparticulate toxicity studies, especially in applications where more than one nanoparticle material-type is present.

Fabrication of luminescent CdS nanoparticles on short-peptide-based hydrogel nanofibers: tuning of optoelectronic properties.

PubMed

Palui, Goutam; Nanda, Jayanta; Ray, Sudipta; Banerjee, Arindam

2009-07-13

The pH-induced self-assembly of three synthetic tripeptides in water medium is used to immobilize luminescent CdS nanoparticles. These peptides form a nanofibrillar network structure upon gelation in aqueous medium at basic pH values (pH 11.0-13.0), and the fabrication of CdS nanoparticles on the gel nanofiber confers the luminescent property to these gels. Atomic force microscopy, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy clearly reveal the presence of CdS nanoparticles in a well-defined array on the gel nanofibers. This is a convenient way to make organic nanofiber-inorganic nanoparticle hybrid nanocomposite systems. The size of the CdS nanoparticles remains almost same before and after deposition on the gel nanofiber. Photoluminescence (PL) measurement of the CdS nanoparticles upon deposition on the gel nanofibers shows a significant blue shift in the emission spectrum of the nanoparticles, and there is a considerable change in the PL gap energy of the CdS nanoparticles after immobilization on different gel nanofibrils. This finding suggests that the optoelectronic properties of CdS nanoparticles can be tuned upon deposition on gel nanofibers without changing the size of the nanoparticles.

The effect of green synthesized gold nanoparticles on rice germination and roots

NASA Astrophysics Data System (ADS)

Tsi Ndeh, Nji; Maensiri, Santi; Maensiri, Duangkamol

2017-09-01

In this paper, gold nanoparticles were synthesized by means of a green approach with Tiliacora triandra leaf extracts under different conditions. No additional reducing or capping agents were employed. The gold nanoparticles were characterized using UV-visible spectrophotometry, transmission electron microscope, x-ray diffraction and Fourier transform infrared spectroscopy. Gold nanoparticles synthesized at temperature of 80 °C were further used to treat rice (Oryza sativa) grains at different concentrations (0, 10, 100, 500, 1000, 2000 mg l-1) for one week. While germination percentages were high (95-98.38%), a slight decrease in root and shoot lengths relative to the control was observed. Phytotoxicity results indicated that the plant synthesized gold nanoparticles were of minimal toxicity to rice seedlings. Increases in cell death, hydrogen peroxide formation and lipid peroxidation in roots and shoots were noted. However, these increases were not statistically significant. The overall results confirmed that Tiliacora triandra synthesized gold nanoparticles are biocompatible and can be potentially used as nanocarriers in agriculture. Contribution at 5th Thailand International Nanotechnology Conference (Nano Thailand-2016), 27-29 November 2016, Nakhon Ratchasima, Thailand.

Factors affecting drug encapsulation and stability of lipid-polymer hybrid nanoparticles.

PubMed

Cheow, Wean Sin; Hadinoto, Kunn

2011-07-01

Lipid-polymer hybrid nanoparticles are polymeric nanoparticles enveloped by lipid layers that combine the highly biocompatible nature of lipids with the structural integrity afforded by polymeric nanoparticles. Recognizing them as attractive drug delivery vehicles, antibiotics are encapsulated in the present work into hybrid nanoparticles intended for lung biofilm infection therapy. Modified emulsification-solvent-evaporation methods using lipid as surfactant are employed to prepare the hybrid nanoparticles. Biodegradable poly (lactic-co-glycolic acid) and phosphatidylcholine are used as the polymer and lipid models, respectively. Three fluoroquinolone antibiotics (i.e. levofloxacin, ciprofloxacin, and ofloxacin), which vary in their ionicity, lipophilicity, and aqueous solubility, are used. The hybrid nanoparticles are examined in terms of their drug encapsulation efficiency, drug loading, stability, and in vitro drug release profile. Compared to polymeric nanoparticles prepared using non-lipid surfactants, hybrid nanoparticles in general are larger and exhibit higher drug loading, except for the ciprofloxacin-encapsulated nanoparticles. Hybrid nanoparticles, however, are unstable in salt solutions, but the stability can be conferred by adding TPGS into the formulation. Drug-lipid ionic interactions and drug lipophilicity play important roles in the hybrid nanoparticle preparation. First, interactions between oppositely charged lipid and antibiotic (i.e. ciprofloxacin) during preparation cause failed nanoparticle formation. Charge reversal of the lipid facilitated by adding counterionic surfactants (e.g. stearylamine) must be performed before drug encapsulation can take place. Second, drug loading and the release profile are strongly influenced by drug lipophilicity, where more lipophilic drug (i.e. levofloxacin) exhibit a higher drug loading and a sustained release profile attributed to the interaction with the lipid coat. Copyright © 2011 Elsevier B.V. All

Bactericidal activity of partially oxidized nanodiamonds.

PubMed

Wehling, Julia; Dringen, Ralf; Zare, Richard N; Maas, Michael; Rezwan, Kurosch

2014-06-24

Nanodiamonds are a class of carbon-based nanoparticles that are rapidly gaining attention, particularly for biomedical applications, i.e., as drug carriers, for bioimaging, or as implant coatings. Nanodiamonds have generally been considered biocompatible with a broad variety of eukaryotic cells. We show that, depending on their surface composition, nanodiamonds kill Gram-positive and -negative bacteria rapidly and efficiently. We investigated six different types of nanodiamonds exhibiting diverse oxygen-containing surface groups that were created using standard pretreatment methods for forming nanodiamond dispersions. Our experiments suggest that the antibacterial activity of nanodiamond is linked to the presence of partially oxidized and negatively charged surfaces, specifically those containing acid anhydride groups. Furthermore, proteins were found to control the bactericidal properties of nanodiamonds by covering these surface groups, which explains the previously reported biocompatibility of nanodiamonds. Our findings describe the discovery of an exciting property of partially oxidized nanodiamonds as a potent antibacterial agent.

Understanding how social networking influences perceived satisfaction with conference experiences

USGS Publications Warehouse

van Riper, Carena J.; van Riper, Charles; Kyle, Gerard T.; Lee, Martha E.

2013-01-01

Social networking is a key benefit derived from participation in conferences that bind the ties of a professional community. Building social networks can lead to satisfactory experiences while furthering participants' long- and short-term career goals. Although investigations of social networking can lend insight into how to effectively engage individuals and groups within a professional cohort, this area has been largely overlooked in past research. The present study investigates the relationship between social networking and satisfaction with the 10th Biennial Conference of Research on the Colorado Plateau using structural equation modelling. Results partially support the hypothesis that three dimensions of social networking – interpersonal connections, social cohesion, and secondary associations – positively contribute to the performance of various conference attributes identified in two focus group sessions. The theoretical and applied contributions of this paper shed light on the social systems formed within professional communities and resource allocation among service providers.

Generic approach for synthesizing asymmetric nanoparticles and nanoassemblies

DOEpatents

Sun, Yugang; Hu, Yongxing

2015-05-26

A generic route for synthesis of asymmetric nanostructures. This approach utilizes submicron magnetic particles (Fe.sub.3O.sub.4--SiO.sub.2) as recyclable solid substrates for the assembly of asymmetric nanostructures and purification of the final product. Importantly, an additional SiO.sub.2 layer is employed as a mediation layer to allow for selective modification of target nanoparticles. The partially patched nanoparticles are used as building blocks for different kinds of complex asymmetric nanostructures that cannot be fabricated by conventional approaches. The potential applications such as ultra-sensitive substrates for surface enhanced Raman scattering (SERS) have been included.

Exploration of the Factors That Support Learning: Web-Based Activity and Testing Systems in Community College Algebra [Conference Long Paper

ERIC Educational Resources Information Center

Hauk, Shandy; Matlen, Bryan J.

2017-01-01

This is an extended conference proceedings report [Long Paper] based on a shorter contributed report at the same conference. A variety of computerized learning platforms exist. In mathematics, most include sets of problems to complete. Feedback to users ranges from a single word like "Correct!" to offers of hints and partially- to…

Induction of protective anti-CTL epitope responses against HER-2-positive breast cancer based on multivalent T7 phage nanoparticles.

PubMed

Pouyanfard, Somayeh; Bamdad, Taravat; Hashemi, Hamidreza; Bandehpour, Mojgan; Kazemi, Bahram

2012-01-01

We report here the development of multivalent T7 bacteriophage nanoparticles displaying an immunodominant H-2k(d)-restricted CTL epitope derived from the rat HER2/neu oncoprotein. The immunotherapeutic potential of the chimeric T7 nanoparticles as anti-cancer vaccine was investigated in BALB/c mice in an implantable breast tumor model. The results showed that T7 phage nanoparticles confer a high immunogenicity to the HER-2-derived minimal CTL epitope, as shown by inducing robust CTL responses. Furthermore, the chimeric nanoparticles protected mice against HER-2-positive tumor challenge in both prophylactic and therapeutic setting. In conclusion, these results suggest that CTL epitope-carrying T7 phage nanoparticles might be a promising approach for development of T cell epitope-based cancer vaccines.

Induction of Protective Anti-CTL Epitope Responses against HER-2-Positive Breast Cancer Based on Multivalent T7 Phage Nanoparticles

PubMed Central

Pouyanfard, Somayeh; Bamdad, Taravat; Hashemi, Hamidreza; Bandehpour, Mojgan; Kazemi, Bahram

2012-01-01

We report here the development of multivalent T7 bacteriophage nanoparticles displaying an immunodominant H-2kd-restricted CTL epitope derived from the rat HER2/neu oncoprotein. The immunotherapeutic potential of the chimeric T7 nanoparticles as anti-cancer vaccine was investigated in BALB/c mice in an implantable breast tumor model. The results showed that T7 phage nanoparticles confer a high immunogenicity to the HER-2-derived minimal CTL epitope, as shown by inducing robust CTL responses. Furthermore, the chimeric nanoparticles protected mice against HER-2-positive tumor challenge in both prophylactic and therapeutic setting. In conclusion, these results suggest that CTL epitope-carrying T7 phage nanoparticles might be a promising approach for development of T cell epitope-based cancer vaccines. PMID:23166703

Novel resveratrol nanodelivery systems based on lipid nanoparticles to enhance its oral bioavailability

PubMed Central

Neves, Ana Rute; Lúcio, Marlene; Martins, Susana; Lima, José Luís Costa; Reis, Salette

2013-01-01

Introduction Resveratrol is a polyphenol found in grapes and red wines. Interest in this polyphenol has increased due to its pharmacological cardio- and neuroprotective, chemopreventive, and antiaging effects, among others. Nevertheless, its pharmacokinetic properties are less favorable, since the compound has poor bioavailability, low water solubility, and is chemically unstable. To overcome these problems, we developed two novel resveratrol nanodelivery systems based on lipid nanoparticles to enhance resveratrol’s oral bioavailability for further use in medicines, supplements, and nutraceuticals. Methods and materials Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) loaded with resveratrol were successfully produced by a modified hot homogenization technique. These were completely characterized to evaluate the quality of the developed resveratrol-loaded nanoparticles. Results Cryo-scanning electron microscopy morphology studies showed spherical and uniform nanoparticles with a smooth surface. An average resveratrol entrapment efficiency of ~70% was obtained for both SLNs and NLCs. Dynamic light scattering measurements gave a Z-average of 150–250 nm, polydispersity index of ~0.2, and a highly negative zeta potential of around −30 mV with no statistically significant differences in the presence of resveratrol. These characteristics remained unchanged for at least 2 months, suggesting good stability. Differential scanning calorimetry studies confirmed the solid state of the SLNs and NLCs at both room and body temperatures. The NLCs had a less ordered crystalline structure conferred by the inclusion of the liquid lipid, since they had lower values for phase transition temperature, melting enthalpy, and the recrystallization index. The presence of resveratrol induced a disorder in the crystal structure of the nanoparticles, suggesting a favoring of its entrapment. The in vitro release studies on conditions of storage showed a negligible

Support for the 2001 Gordon Research Conference on the Origins of Solar Systems

NASA Technical Reports Server (NTRS)

Stevenson, David J.

2002-01-01

This grant provided partial support for participants at the Gordon Research Conference on Origins of Solar Systems, held at Connecticut College, June 17 through June 22, 2001. This conference was chaired by the PI (David Stevenson) and Pat Cassell (NASA Ames) was Vice-Chair. In addition to the money provided by this grant ($15,000), the Gordon Research Conference organization provided about $22,000 (in large part from registration fees) and BPI provided $10,000 (through Director David Black); the latter targeted primarily for students and postdocs. Accordingly the grant money from NASA was used to cover the costs of registration and travel for about one half of the invited speakers (22 in total) and discussion leaders (about 10 in total).

Support for the 2001 Gordon Research Conference on the Origins of Solar Systems

NASA Astrophysics Data System (ADS)

Stevenson, David J.

2002-01-01

This grant provided partial support for participants at the Gordon Research Conference on Origins of Solar Systems, held at Connecticut College, June 17 through June 22, 2001. This conference was chaired by the PI (David Stevenson) and Pat Cassell (NASA Ames) was Vice-Chair. In addition to the money provided by this grant (15,000), the Gordon Research Conference organization provided about 22,000 (in large part from registration fees) and BPI provided 10,000 (through Director David Black); the latter targeted primarily for students and postdocs. Accordingly the grant money from NASA was used to cover the costs of registration and travel for about one half of the invited speakers (22 in total) and discussion leaders (about 10 in total).

"Clickable", trifunctional magnetite nanoparticles and their chemoselective biofunctionalization.

PubMed

Das, Manasmita; Bandyopadhyay, Debarati; Mishra, Debasish; Datir, Satyajit; Dhak, Prasanta; Jain, Sanyog; Maiti, Tapas Kumar; Basak, Amit; Pramanik, Panchanan

2011-06-15

A multifunctional iron oxide based nanoformulation for combined cancer-targeted therapy and multimodal imaging has been meticulously designed and synthesized using a chemoselective ligation approach. Novel superparamagnetic magnetite nanoparticles simultaneously functionalized with amine, carboxyl, and azide groups were fabricated through a sequence of stoichiometrically controllable partial succinylation and Cu (II) catalyzed diazo transfer on the reactive amine termini of 2-aminoethylphosphonate grafted magnetite nanoparticles (MNPs). Functional moieties associated with MNP surface were chemoselectively conjugated with rhodamine B isothiocyanate (RITC), propargyl folate (FA), and paclitaxel (PTX) via tandem nucleophic addition of amine to isothithiocyanates, Cu (I) catalyzed azide--alkyne click chemistry and carbodiimide-promoted esterification. An extensive in vitro study established that the bioactives chemoselectively appended to the magnetite core bequeathed multifunctionality to the nanoparticles without any loss of activity of the functional molecules. Multifunctional nanoparticles, developed in the course of the study, could selectively target and induce apoptosis to folate-receptor (FR) overexpressing cancer cells with enhanced efficacy as compared to the free drug. In addition, the dual optical and magnetic properties of the synthesized nanoparticles aided in the real-time tracking of their intracellular pathways also as apoptotic events through dual fluorescence and MR-based imaging.

Effect of silver on the shape of palladium nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Dikshita, E-mail: dgmonugupta@gmail.com; Barman, P. B.; Hazra, S. K.

We report a facile route to prepare palladium-silver nanoparticles at considerably low temperature. First the controlled synthesis of palladium nanoparticles was performed via reduction of sodium tetrachloropalladate (II) in ethylene glycol in the presence of PVP(polyvinylpyrrolidone) as capping agent. The reaction was carried out at three different temperatures-80°C, 100°C and 120°C for one hour. Short reaction time and low synthesis temperature adds advantage to this method over others. Formed palladium nanoparticles were nearly spherical with the average particle size of 7.5±0.5 nm, 9.5±0.5 nm and 10.5±0.5 nm at 80°C, 100°C and 120°C respectively. Secondly, the palladium-silver nanoparticles were prepared bymore » the simultaneous reduction of palladium and silver from their respective precursors in ethylene glycol at 100°C (optimized temperature). The shape and size distribution was studied by TEM (Transmission Electron Microscopy). The role of silver in transforming the shape of palladium nanoparticles from spherical to triangular has been discussed. Spherical symmetry of palladium nanoparticles is disturbed by the interaction of silver ions on the crystal facets of palladium nanoparticles. From UV-vis spectra, the absorption maxima of palladium nanoparticles at 205 nm and absorption maxima of palladium-silver nanoparticles at 272 nm revealed the partial evidence of their formation.« less

Surface modified gold nanoparticles for SERS based detection of vulnerable plaque formations (Conference Presentation)

NASA Astrophysics Data System (ADS)

Matthäus, Christian; Dugandžić, Vera; Weber, Karina; Cialla-May, Dana; Popp, Jürgen

2017-02-01

Cardiovascular diseases are the leading cause of death worldwide. Atherosclerosis is closely related to the majority of these diseases, as a process of thickening and stiffening of the arterial walls through accumulation of lipids, which is a consequence of aging and life style. Atherosclerosis affects all people in some extent, but not all arterial plaques will necessarily lead to the complications, such as thrombosis, stroke and heart attack. One of the greatest challenges in the risk assessment of atherosclerotic depositions is the detection and recognition of plaques which are unstable and prone to rupture. These vulnerable plaques usually consist of a lipid core that attracts macrophages, a type of white blood cells that are responsible for the degradation of lipids. It has been hypothesized that the amount of macrophages relates to the overall plaque stability. As phagocytes, macrophages also act as recipients for nanoscale particles or structures. Administered gold nanoparticles are usually rabidly taken up by macrophages residing within arterial walls and can therefore be indirectly detected. A very sensitive strategy for probing gold nanoparticles is by utilizing surface enhanced Raman scattering (SERS). By modifying the surface of these particles with SERS active labels it is possible to generate highly specific signals that exhibit sensitivity comparable to fluorescence. SERS labeled gold nanoparticles have been synthesized and the uptake dynamics and efficiency on macrophages in cell cultures was investigated using Raman microscopic imaging. The results clearly show that nanoparticles are taken up by macrophages and support the potential of SERS spectroscopy for the detection of vulnerable plaques. Acknowledgements: Financial support from the Carl Zeiss Foundation is highly acknowledged. The project "Jenaer Biochip Initiative 2.0" (03IPT513Y) within the framework "InnoProfile Transfer - Unternehmen Region" is supported by the Federal Ministry of

Biomimetic synthesis of chiral erbium-doped silver/peptide/silica core-shell nanoparticles (ESPN)

NASA Astrophysics Data System (ADS)

Mantion, Alexandre; Graf, Philipp; Florea, Ileana; Haase, Andrea; Thünemann, Andreas F.; Mašić, Admir; Ersen, Ovidiu; Rabu, Pierre; Meier, Wolfgang; Luch, Andreas; Taubert, Andreas

2011-12-01

Peptide-modified silver nanoparticles have been coated with an erbium-doped silica layer using a method inspired by silica biomineralization. Electron microscopy and small-angle X-ray scattering confirm the presence of an Ag/peptide core and silica shell. The erbium is present as small Er2O3 particles in and on the silica shell. Raman, IR, UV-Vis, and circular dichroism spectroscopies show that the peptide is still present after shell formation and the nanoparticles conserve a chiral plasmon resonance. Magnetic measurements find a paramagnetic behavior. In vitro tests using a macrophage cell line model show that the resulting multicomponent nanoparticles have a low toxicity for macrophages, even on partial dissolution of the silica shell.Peptide-modified silver nanoparticles have been coated with an erbium-doped silica layer using a method inspired by silica biomineralization. Electron microscopy and small-angle X-ray scattering confirm the presence of an Ag/peptide core and silica shell. The erbium is present as small Er2O3 particles in and on the silica shell. Raman, IR, UV-Vis, and circular dichroism spectroscopies show that the peptide is still present after shell formation and the nanoparticles conserve a chiral plasmon resonance. Magnetic measurements find a paramagnetic behavior. In vitro tests using a macrophage cell line model show that the resulting multicomponent nanoparticles have a low toxicity for macrophages, even on partial dissolution of the silica shell. Electronic supplementary information (ESI) available: Figures S1 to S12, Tables S1 and S2. See DOI: 10.1039/c1nr10930h

Modeling ultrafast laser-induced nanocavitation around plasmonic nanoparticles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Meunier, Michel; Dagallier, Adrien; Lachaine, Rémi; Boutopoulos, Christos; Boulais, Étienne

2017-03-01

Vapor nanobubbles generated around plasmonic nanoparticles (NPs) by ultrafast laser irradiation are efficient for inducing localized damage to living cells. Killing targeted cancer cells or gene delivery can therefore be envisioned using this new technology [1,2]. The extent of the damage and its non-lethal character are linked to the size of the nanobubble. Precise understanding of the mechanisms leading to bubble formation around plasmonic nanostructures is necessary to optimize the technique. In this presentation, we present a complete model that successfully describes all interactions occurring during the irradiation of plasmonics nanostructures by an ultrafast laser of various pulse widths and fluences. Nanoavitation is caused by the interplay between heat conduction at the NP-medium interface and non-linear plasmon-enhanced photoionization of a nanoplasma in the near-field [3-5], the former being dominant for in-resonance and the latter for off-resonance irradiation. Modeling of the whole laser-nanoparticle interaction, together with the help of the shadowgraphic imaging and scattering techniques [3-5], give valuable insight on the mechanisms of cavitation at the nanoscale, leading to possible optimization of the nanostructure for bubble-based nanomedicine applications. 1- E. Boulais, R. Lachaine, A. Hatef, and M. Meunier, Journal of Photochemistry and Photobiology C: Photochemistry Reviews 17, 26-49 (2013). 2- E. Bergeron, S. Patskovsky, D. Rioux, and M. Meunier, Nanoscale 7,17836-17847 (2015). 3- E. Boulais, R. Lachaine, and M. Meunier, Nano Letters 12, 4763-4769 (2012). 4- R. Lachaine, E. Boulais, and M. Meunier, ACS Photonics 1, 331-336 (2014). 5- C. Boutopoulos, A. Hatef, M. Fortin-Deschênes, and M. Meunier Nanoscale 7,11758-11765 (2015).

The biomolecular corona of nanoparticles in circulating biological media

NASA Astrophysics Data System (ADS)

Pozzi, D.; Caracciolo, G.; Digiacomo, L.; Colapicchioni, V.; Palchetti, S.; Capriotti, A. L.; Cavaliere, C.; Zenezini Chiozzi, R.; Puglisi, A.; Laganà, A.

2015-08-01

When nanoparticles come into contact with biological media, they are covered by a biomolecular `corona', which confers a new identity to the particles. In all the studies reported so far nanoparticles are incubated with isolated plasma or serum that are used as a model for protein adsorption. Anyway, bodily fluids are dynamic in nature so the question arises on whether the incubation protocol, i.e. dynamic vs. static incubation, could affect the composition and structure of the biomolecular corona. Here we let multicomponent liposomes interact with fetal bovine serum (FBS) both statically and dynamically, i.e. in contact with circulating FBS (~40 cm s-1). The structure and composition of the liposome-protein corona, as determined by dynamic light scattering, electrophoretic light scattering and liquid chromatography tandem mass spectrometry, were found to be dependent on the incubation protocol. Specifically, following dynamic exposure to FBS, multicomponent liposomes were less enriched in complement proteins and appreciably more enriched in apolipoproteins and acute phase proteins (e.g. alpha-1-antitrypsin and inter-alpha-trypsin inhibitor heavy chain H3) that are involved in relevant interactions between nanoparticles and living systems. Supported by our results, we speculate that efficient predictive modeling of nanoparticle behavior in vivo will require accurate knowledge of nanoparticle-specific protein fingerprints in circulating biological media.When nanoparticles come into contact with biological media, they are covered by a biomolecular `corona', which confers a new identity to the particles. In all the studies reported so far nanoparticles are incubated with isolated plasma or serum that are used as a model for protein adsorption. Anyway, bodily fluids are dynamic in nature so the question arises on whether the incubation protocol, i.e. dynamic vs. static incubation, could affect the composition and structure of the biomolecular corona. Here we let

Frequency of alleles conferring resistance to a Bacillus thuringiensis toxin in a Philippine population of Scirpophaga incertulas (Lepidoptera: Pyralidae).

PubMed

Bentur, J S; Andow, D A; Cohen, M B; Romena, A M; Gould, F

2000-10-01

Using the F2 screen methodology, we estimated the frequency of alleles conferring resistance to the Cry1Ab toxin of Bacillus thuringiensis Berliner in a Philippine population of the stem borer Scirpophaga incertulas (Walker). Evaluation of >450 isofemale lines for survival of F2 larvae on cry1Ab plants did not detect the presence of an allele conferring a high level of resistance. The frequency of such an allele in the sampled population was conservatively estimated to be <3.6 x 10(-3) with 95% confidence and a detection probability of 94%. However, there was evidence of the presence of alleles conferring partial resistance to Cry1Ab. The frequency of alleles for partial resistance was estimated as 4.8 x 10(-3) with a 95% CI between 1.3 x 10(-3) and 1.04 x 10(-2) and a detection probability of 94%. Our results suggest that the frequency of alleles conferring resistance to Cry1Ab in the population of S. incertulas sampled is not too high to preclude successful implementation of the high dose/refuge resistance management strategy.

Tailoring of the partial magnonic gap in three-dimensional magnetoferritin-based magnonic crystals

NASA Astrophysics Data System (ADS)

Mamica, S.

2013-07-01

We investigate theoretically the use of magnetoferritin nanoparticles, self-assembled in the protein crystallization process, as the basis for the realization of 3D magnonic crystals in which the interparticle space is filled with a ferromagnetic material. Using the plane wave method we study the dependence of the width of the partial band gap and its central frequency on the total magnetic moment of the magnetoferritin core and the lattice constant of the magnetoferritin crystal. We show that by adjusting the combination of these two parameters the partial gap can be tailored in a wide frequency range and shifted to sub-terahertz frequencies. Moreover, the difference in the width of the partial gap for spin waves propagating in planes parallel and perpendicular to the external field allows for switching on and off the partial magnonic gap by changing the direction of the applied field.

International Conference: Milky Way Surveys: The Structure and Evolution of Our Galaxy

NASA Technical Reports Server (NTRS)

Clemens, Dan

2004-01-01

We were granted NASA support for partial sponsorship of an international conference on Galactic science, held June 15-17, 2003 and hosted by the Institute for Astrophysical Research at Boston University. This conference, entitled 'Milky Way Surveys: The Structure and Evolution of Our Galaxy' drew some 125 scientific experts, researchers, and graduate students to Boston to: (1) Present large area survey plans and findings; (2) Discuss important remaining questions and puzzles in Galactic science; and (3) To inform and excite students and researchers about the potential for using large area survey databases to address key Galactic science questions. An international Scientific Organizing Committee for this conference crafted a tightly packed two-day conference designed to highlight many recent and upcoming large area surveys (including 2MASS, SDSS, MSX, VLA-HI, GRS, and SIRTF/GLIMPSE) and current theoretical understandings and questions. By bringing together experts in the conduct of Galactic surveys and leading theorists, new ways of attacking long-standing scientific questions were encouraged. The titles of most of the talks and posters presented are attached to the end of this report.

Potential of using cerium oxide nanoparticles for protecting healthy tissue during accelerated partial breast irradiation (APBI)

PubMed Central

Ouyang, Zi; Mainali, Madan Kumar; Sinha, Neeharika; Strack, Guinevere; Altundal, Yucel; Hao, Yao; Winningham, Thomas Andrew; Sajo, Erno; Celli, Jonathan; Ngwa, Wilfred

2016-01-01

The purpose of this study is to investigate the feasibility of using cerium oxide nanoparticles (CONPs) as radical scavengers during accelerated partial breast irradiation (APBI) to protect normal tissue. We hypothesize that CONPs can be slowly released from the routinely used APBI balloon applicators—via a degradable coating—and protect the normal tissue on the border of the lumpectomy cavity over the duration of APBI. To assess the feasibility of this approach, we analytically calculated the initial concentration of CONPs required to protect normal breast tissue from reactive oxygen species (ROS) and the time required for the particles to diffuse to various distances from the lumpectomy wall. Given that cerium has a high atomic number, we took into account the possible inadvertent dose enhancement that could occur due to the photoelectric interactions with radiotherapy photons. To protect against a typical MammoSite treatment fraction of 3.4 Gy, 5 ng-g−1 of CONPs is required to scavenge hydroxyl radicals and hydrogen peroxide. Using 2 nm sized NPs, with an initial concentration of 1 mg-g−1, we found that 2–10 days of diffusion is required to obtain desired concentrations of CONPs in regions 1–2 cm away from the lumpectomy wall. The resultant dose enhancement factor (DEF) is less than 1.01 under such conditions. Our results predict that CONPs can be employed for radioprotection during APBI using a new design in which balloon applicators are coated with the NPs for sustained/controlled in-situ release from within the lumpectomy cavity. PMID:27053452

Chitosan nanoparticles from marine squid protect liver cells against N-diethylnitrosoamine-induced hepatocellular carcinoma.

PubMed

Subhapradha, Namasivayam; Shanmugam, Vairamani; Shanmugam, Annaian

2017-09-01

Rationale of this study was framed to investigate the protective effect and anti-cancer property of nanoparticles based on chitosan isolated from squid, Sepioteuthis lessoniana, on hepatic cells in N-Nitrosodiethylamine-induced hepatocellular carcinoma in rats. The results conferred that the chitosan nanoparticle supplementation had a protective effect on liver cells by reducing the levels of marker enzymes and bilirubin and thus increasing the albumin levels. The level of reduced glutathione, ascorbic acid and α-tocopherol significantly increased in both post- and pre-treatment with chitosan nanoparticles. The levels of antioxidant enzymes were enhanced and lipid peroxidation products were diminished while treating nitrosodiethylamine-induced hepatocellular carcinoma with chitosan nanoparticles. Supplementation of chitosan nanoparticles had potent anti-hyperlipidemic property that was evidenced by monitoring the serum lipid levels and its components. Animals pre-treated with chitosan nanoparticles along with nitrosodiethylamine showed a significant reduction in the total cholesterol and triglycerides levels with increase in the levels of phospholipids and free fatty acids. Chitosan nanoparticles treated rats showed significant increment in high-density lipoprotein cholesterol and reduction in low-density lipoprotein and very low-density lipoprotein cholesterol when compared with levels in nitrosodiethylamine-induced hepatocellular carcinoma. Nitrosodiethylamine-induced carcinoma changes on circulation and hepatic antioxidant defense mechanism were regulated by chitosan nanoparticles, concluding that the chitosan nanoparticles have a potent protective effect on liver cells which might be due to its robust antioxidant and anti-lipidemic property. Copyright © 2017 Elsevier Ltd. All rights reserved.

TiO2 nanoparticles aggregation and disaggregation in presence of alginate and Suwannee River humic acids. pH and concentration effects on nanoparticle stability.

PubMed

Loosli, Frédéric; Le Coustumer, Philippe; Stoll, Serge

2013-10-15

The behavior of manufactured TiO2 nanoparticles is studied in a systematic way in presence of alginate and Suwannee River humic acids at variable concentrations. TiO2 nanoparticles aggregation, disaggregation and stabilization are investigated using dynamic light scattering and electrophoretic experiments allowing the measurement of z-average hydrodynamic diameters and zeta potential values. Stability of the TiO2 nanoparticles is discussed by considering three pH-dependent electrostatic scenarios. In the first scenario, when pH is below the TiO2 nanoparticle point of zero charge, nanoparticles exhibit a positively charged surface whereas alginate and Suwannee River humic acids are negatively charged. Fast adsorption at the TiO2 nanoparticles occurs, promotes surface charge neutralization and aggregation. By increasing further alginate and Suwannee River humic acids concentrations charge inversion and stabilization of TiO2 nanoparticles are obtained. In the second electrostatic scenario, at the surface charge neutralization pH, TiO2 nanoparticles are rapidly forming aggregates. Adsorption of alginate and Suwannee River humic acids on aggregates leads to their partial fragmentation. In the third electrostatic scenario, when nanoparticles, alginate and Suwannee River humic acids are negatively charged, only a small amount of Suwannee River humic acids is adsorbed on TiO2 nanoparticles surface. It is found that the fate and behavior of individual and aggregated TiO2 nanoparticles in presence of environmental compounds are mainly driven by the complex interplay between electrostatic attractive and repulsive interactions, steric and van der Waals interactions, as well as concentration ratio. Results also suggest that environmental aquatic concentration ranges of humic acids and biopolymers largely modify the stability of aggregated or dispersed TiO2 nanoparticles. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ultrasound-guided photoacoustic imaging of lymph nodes with biocompatible gold nanoparticles as a novel contrast agent (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sun, In-Cheol; Dumani, Diego; Emelianov, Stanislav Y.

2017-02-01

A key step in staging cancer is the diagnosis of metastasis that spreads through lymphatic system. For this reason, researchers develop various methods of sentinel lymph node mapping that often use a radioactive tracer. This study introduces a safe, cost-effective, high-resolution, high-sensitivity, and real-time method of visualizing the sentinel lymph node: ultrasound-guided photoacoustic (US/PA) imaging augmented by a contrast agent. In this work, we use clearable gold nanoparticles covered by a biocompatible polymer (glycol chitosan) to enhance cellular uptake by macrophages abundant in lymph nodes. We incubate macrophages with glycol-chitosan-coated gold nanoparticles (0.05 mg Au/ml), and then fix them with paraformaldehyde solution for an analysis of in vitro dark-field microscopy and cell phantom. The analysis shows enhanced cellular uptake of nanoparticles by macrophages and strong photoacoustic signal from labeled cells in tissue-mimicking cell phantoms consisting gelatin solution (6 %) with silica gel (25 μm, 0.3%) and fixed macrophages (13 X 105 cells). The in-vivo US/PA imaging of cervical lymph nodes in healthy mice (nu/nu, female, 5 weeks) indicates a strong photoacoustic signal from a lymph node 10 minutes post-injection (2.5 mg Au/ml, 80 μl). The signal intensity and the nanoparticle-labeled volume of tissue within the lymph node continues to increase until 4 h post-injection. Histological analysis further confirms the accumulation of gold nanoparticles within the lymph nodes. This work suggests the feasibility of molecular/cellular US/PA imaging with biocompatible gold nanoparticles as a photoacoustic contrast agent in the diagnosis of lymph-node-related diseases.

Back scattering involving embedded silicon nitride (SiN) nanoparticles for c-Si solar cells

NASA Astrophysics Data System (ADS)

Ghosh, Hemanta; Mitra, Suchismita; Siddiqui, M. S.; Saxena, A. K.; Chaudhuri, Partha; Saha, Hiranmay; Banerjee, Chandan

2018-04-01

A novel material, structure and method of synthesis for dielectric light trapping have been presented in this paper. First, the light scattering behaviour of silicon nitride nanoparticles have been theoretically studied in order to find the optimized size for dielectric back scattering by FDTD simulations from Lumerical Inc. The optical results have been used in electrical analysis and thereby, estimate the effect of nanoparticles on efficiency of the solar cells depending on substrate thickness. Experimentally, silicon nitride (SiN) nanoparticles have been formed using hydrogen plasma treatment on SiN layer deposited by Plasma Enhanced Chemical Vapour Deposition (PECVD). The size and area coverage of the nanoparticles were controlled by varying the working pressure, power density and treatment duration. The nanoparticles were integrated with partial rear contact c-Si solar cells as dielectric back reflector structures for the light trapping in thin silicon solar cells. Experimental results revealed the increases of current density by 2.7% in presence of SiN nanoparticles.

Governing factors affecting the impacts of silver nanoparticles on wastewater treatment.

PubMed

Zhang, Chiqian; Hu, Zhiqiang; Li, Ping; Gajaraj, Shashikanth

2016-12-01

Silver nanoparticles (nanosilver or AgNPs) enter municipal wastewater from various sources, raising concerns about their potential adverse effects on wastewater treatment processes. We argue that the biological effects of silver nanoparticles at environmentally realistic concentrations (μgL -1 or lower) on the performance of a full-scale municipal water resource recovery facility (WRRF) are minimal. Reactor configuration is a critical factor that reduces or even mutes the toxicity of silver nanoparticles towards wastewater microbes in a full-scale WRRF. Municipal sewage collection networks transform silver nanoparticles into silver(I)-complexes/precipitates with low ecotoxicity, and preliminary/primary treatment processes in front of biological treatment utilities partially remove silver nanoparticles to sludge. Microbial functional redundancy and microbial adaptability to silver nanoparticles also greatly alleviate the adverse effects of silver nanoparticles on the performance of a full-scale WRRF. Silver nanoparticles in a lab-scale bioreactor without a sewage collection system and/or a preliminary/primary treatment process, in contrast to being in a full scale system, may deteriorate the reactor performance at relatively high concentrations (e.g., mgL -1 levels or higher). However, in many cases, silver nanoparticles have minimal impacts on lab-scale bioreactors, such as sequencing batch bioreactors (SBRs), especially when at relatively low concentrations (e.g., less than 1mgL -1 ). The susceptibility of wastewater microbes to silver nanoparticles is species-specific. In general, silver nanoparticles have higher toxicity towards nitrifying bacteria than heterotrophic bacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

Photoinduced Disaggregation of TiO2 Nanoparticles Enables Transdermal Penetration

PubMed Central

Bennett, Samuel W.; Zhou, Dongxu; Mielke, Randall; Keller, Arturo A.

2012-01-01

Under many aqueous conditions, metal oxide nanoparticles attract other nanoparticles and grow into fractal aggregates as the result of a balance between electrostatic and Van Der Waals interactions. Although particle coagulation has been studied for over a century, the effect of light on the state of aggregation is not well understood. Since nanoparticle mobility and toxicity have been shown to be a function of aggregate size, and generally increase as size decreases, photo-induced disaggregation may have significant effects. We show that ambient light and other light sources can partially disaggregate nanoparticles from the aggregates and increase the dermal transport of nanoparticles, such that small nanoparticle clusters can readily diffuse into and through the dermal profile, likely via the interstitial spaces. The discovery of photoinduced disaggregation presents a new phenomenon that has not been previously reported or considered in coagulation theory or transdermal toxicological paradigms. Our results show that after just a few minutes of light, the hydrodynamic diameter of TiO2 aggregates is reduced from ∼280 nm to ∼230 nm. We exposed pigskin to the nanoparticle suspension and found 200 mg kg−1 of TiO2 for skin that was exposed to nanoparticles in the presence of natural sunlight and only 75 mg kg−1 for skin exposed to dark conditions, indicating the influence of light on NP penetration. These results suggest that photoinduced disaggregation may have important health implications. PMID:23155401

Investigating Catalytic Properties of Composite Nanoparticle Assemblies

DTIC Science & Technology

2001-11-01

electrode surfaces, were found to be catalytically active towards electrooxidation of CO and MeOH upon activation. The activation involved partial removal...to proceed under stirring at room temperature for 4 hours. producing a dark-brown solution of DT-encapsulated nanoparticles that was then cleaned in... ethanol or used in the heating treatment. Processing. Highly-monodispersed Au particles (5.3 ±0.3 nm) were prepared by thermally activated treatment of

CompNanoTox2015: novel perspectives from a European conference on computational nanotoxicology on predictive nanotoxicology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bañares, Miguel A.; Haase, Andrea; Tran, Lang

A first European Conference on Computational Nanotoxicology, CompNanoTox, was held in November 2015 in Benahavís, Spain with the objectives to disseminate and integrate results from the European modeling and database projects (NanoPUZZLES, ModENPTox, PreNanoTox, MembraneNanoPart, MODERN, eNanoMapper and EU COST TD1204 MODENA) as well as to create synergies within the European NanoSafety Cluster. This conference was supported by the COST Action TD1204 MODENA on developing computational methods for toxicological risk assessment of engineered nanoparticles and provided a unique opportunity for crossfertilization among complementary disciplines. The efforts to develop and validate computational models crucially depend on high quality experimental data andmore » relevant assays which will be the basis to identify relevant descriptors. The ambitious overarching goal of this conference was to promote predictive nanotoxicology, which can only be achieved by a close collaboration between the computational scientists (e.g. database experts, modeling experts for structure, (eco) toxicological effects, performance and interaction of nanomaterials) and experimentalists from different areas (in particular toxicologists, biologists, chemists and material scientists, among others). The main outcome and new perspectives of this conference are summarized here.« less

CompNanoTox2015: novel perspectives from a European conference on computational nanotoxicology on predictive nanotoxicology.

PubMed

Bañares, Miguel A; Haase, Andrea; Tran, Lang; Lobaskin, Vladimir; Oberdörster, Günter; Rallo, Robert; Leszczynski, Jerzy; Hoet, Peter; Korenstein, Rafi; Hardy, Barry; Puzyn, Tomasz

2017-09-01

A first European Conference on Computational Nanotoxicology, CompNanoTox, was held in November 2015 in Benahavís, Spain with the objectives to disseminate and integrate results from the European modeling and database projects (NanoPUZZLES, ModENPTox, PreNanoTox, MembraneNanoPart, MODERN, eNanoMapper and EU COST TD1204 MODENA) as well as to create synergies within the European NanoSafety Cluster. This conference was supported by the COST Action TD1204 MODENA on developing computational methods for toxicological risk assessment of engineered nanoparticles and provided a unique opportunity for cross fertilization among complementary disciplines. The efforts to develop and validate computational models crucially depend on high quality experimental data and relevant assays which will be the basis to identify relevant descriptors. The ambitious overarching goal of this conference was to promote predictive nanotoxicology, which can only be achieved by a close collaboration between the computational scientists (e.g. database experts, modeling experts for structure, (eco) toxicological effects, performance and interaction of nanomaterials) and experimentalists from different areas (in particular toxicologists, biologists, chemists and material scientists, among others). The main outcome and new perspectives of this conference are summarized here.

Partial Ionic Character beyond the Pauling Paradigm: Metal Nanoparticles

DOE PAGES

Duanmu, Kaining; Truhlar, Donald G.

2014-11-12

A canonical perspective on the chemical bond is the Pauling paradigm: a bond in a molecule containing only identical atoms has no ionic character. However, we show that homonuclear silver clusters have very uneven charge distributions (for example, the C 2v structure of Ag 4 has a larger dipole moment than formaldehyde or acetone), and we show how to predict the charge distribution from coordination numbers and Hirshfeld charges. The new charge model is validated against Kohn–Sham calculations of dipole moments with four approximations for the exchange–correlation functional. We report Kohn–Sham studies of the binding energies of CO on silvermore » monomer and silver clusters containing 2–18 atoms. We also find that an accurate charge model is essential for understanding the site dependence of binding. In particular we find that atoms with more positive charges tend to have higher binding energies, which can be used for guidance in catalyst modeling and design. Furthermore, the nonuniform charge distribution of silver clusters predisposes the site preference of binding of carbon monoxide, and we conclude that nonuniform charge distributions are an important property for understanding binding of metal nanoparticles in general.« less

Highly Stable, Functional Hairy Nanoparticles and Biopolymers from Wood Fibers: Towards Sustainable Nanotechnology.

PubMed

Sheikhi, Amir; Yang, Han; Alam, Md Nur; van de Ven, Theo G M

2016-07-20

Nanoparticles, as one of the key materials in nanotechnology and nanomedicine, have gained significant importance during the past decade. While metal-based nanoparticles are associated with synthetic and environmental hassles, cellulose introduces a green, sustainable alternative for nanoparticle synthesis. Here, we present the chemical synthesis and separation procedures to produce new classes of hairy nanoparticles (bearing both amorphous and crystalline regions) and biopolymers based on wood fibers. Through periodate oxidation of soft wood pulp, the glucose ring of cellulose is opened at the C2-C3 bond to form 2,3-dialdehyde groups. Further heating of the partially oxidized fibers (e.g., T = 80 °C) results in three products, namely fibrous oxidized cellulose, sterically stabilized nanocrystalline cellulose (SNCC), and dissolved dialdehyde modified cellulose (DAMC), which are well separated by intermittent centrifugation and co-solvent addition. The partially oxidized fibers (without heating) were used as a highly reactive intermediate to react with chlorite for converting almost all aldehyde to carboxyl groups. Co-solvent precipitation and centrifugation resulted in electrosterically stabilized nanocrystalline cellulose (ENCC) and dicarboxylated cellulose (DCC). The aldehyde content of SNCC and consequently surface charge of ENCC (carboxyl content) were precisely controlled by controlling the periodate oxidation reaction time, resulting in highly stable nanoparticles bearing more than 7 mmol functional groups per gram of nanoparticles (e.g., as compared to conventional NCC bearing < 1 mmol functional group/g). Atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) attested to the rod-like morphology. Conductometric titration, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), electrokinetic-sonic-amplitude (ESA) and acoustic attenuation

Monitoring adsorption of gold nanoparticles on gold nanodisk array using dark-field hyperspectral microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Zhao, Fusheng; Zenasni, Oussama; Li, Jingting; Shih, Wei-Chuan

2017-02-01

Localized surface plasmon resonance (LSPR) arises from the interaction of light with noble metal nanoparticles, which induces a collective oscillation in the free electrons. The size and shape of the metallic nanostructure significantly impact LSPR frequency and strength. Nanoplasmonic sensor has become a recent research focus due to its significant signal enhancement and robust signal transduction measured by extinction spectroscopy, fluorescence, Raman scattering, and absorption spectroscopy. Dark-field microscopy, in contrast, reports the scattered photons after light-matter interactions. In this case, the nanoparticles can be understood as dipole radiators whose free electrons oscillate in concert. Coupled with spectroscopy, this platform allows the collection of plasmonically scattered spectra from gold nanoparticles. Plasmonic coupling between electron-beam lithography patterned gold nanodisks (AuND) and colloidal gold nanoparticles (AuNP) can change the plasmonic resonance of the original entities, and can be effectively studied by dark-field hyperspectral microscopy. Typically, a pronounced redshift can be observed when plasmonic coupling occurs. When these nano-entities are functionalized with interactive surface moieties, biochemistry and molecular processes can be studied. In this paper, we will present the capability of assessing the process of immobilizing streptavidin-functionalized AuNPs on an array of biotin-terminated AuNDs. By monitoring changes in the LSPR band of AuNDs, we are able to evaluate similar processes in other molecular systems. In addition, plasmon coupling induced scattering intensity variations can be measured by an electron-multiplied charge-coupled device camera for rapid in situ monitoring. This method can potentially be useful in studying dynamic biophysical and biochemical processes in situ.

Fabrication and electrical characterization of partially metallized vias fabricated by inkjet

NASA Astrophysics Data System (ADS)

Khorramdel, B.; Mäntysalo, M.

2016-04-01

Through silicon vias (TSVs), acting as vertical interconnections, play an important role in micro-electro-mechanical systems (MEMS) 3D wafer level packaging. Today, taking advantage of nanoparticle inks, inkjet technologies as local filling methods could be used to plate the inside the vias with a conductive material, rather than using a current method, such as chemical vapor deposition or electrolytic growth. This could decrease the processing time, cost and waste material produced. In this work, we have fabricated and demonstrated electrical characterization of TSVs with a top diameter of 85 μm, and partially metallized on their inside walls using silver nanoparticle ink and drop-on-demand inkjet printing. Electrical measurement showed that the resistance of a single via with a void free coverage from top to bottom could be less than 4 Ω, which is still acceptable for MEMS applications.

5th Bionanotox and Applications International Research Conference, Peabody, Little Rock, Arkansas, USA

NASA Astrophysics Data System (ADS)

Sabb, Taneicie; Chowdhury, Parimal

2011-06-01

"BioNanoTox and Toxicity: using Technology to Advance Discovery" was this year's theme at the 5th BioNanoTox and Applications International Research Conference held at the Peabody Hotel, Little Rock, Arkansas on November 4-5th, 2010. This year, the international participation in this conference increased to 25 countries spanning the globe. The conference began with opening remarks by Paul Howard, Associate Director of the National Center for Toxicological Research, Food and Drug Administration, Jefferson, Arkansas, United States. Two keynote speakers, Dr. Ananth V. Annapragada and Dr. Merle G. Paule presented lectures on "Toxicity of Novel Nanoparticles for CT imaging" and "The Biology of Neurotoxicity: using Technology to Advance Discovery", respectively. Teachers, students, faculty, and scientists presented oral and poster presentations on fundamental and translational research related to BioNanoTox and related fields of science. Six presentation sessions were held over the two-day conference. There were 31 presentations and 39 posters from disciplines ranging from biology to chemistry, toxicology, nanotechnology, computational sciences, mathematics, engineering, plant science, and biotechnology. Poster presentation awards were presented to three high school students, three high school teachers, and three college students. In addition to poster awards a memorial, travel, and BioNanoTox award were presented. This year's meeting paved the way for a more outstanding meeting for the future.

In situ synthesis of luminescent carbon nanoparticles toward target bioimaging

NASA Astrophysics Data System (ADS)

Sharker, Shazid Md.; Kim, Sung Min; Lee, Jung Eun; Jeong, Ji Hoon; in, Insik; Lee, Kang Dea; Lee, Haeshin; Park, Sung Young

2015-03-01

This paper describes the in situ synthesis of single fluorescence carbon nanoparticles (FCNs) for target bioimaging applications derived from biocompatible hyaluronic acid (HA) without using common conjugation processes. FCNs formed via the dehydration of hyaluronic acid, which were obtained by carbonizing HA, and partially carbonized HA fluorescence carbon nanoparticles (HA-FCNs), formed by a lower degree of carbonization, show good aqueous solubility, small particle size (<20 nm) and different fluorescence intensities with a red shift. After confirming the cytotoxicity of HA-FCNs and FCNs, we carried out in vitro and in vivo bioimaging studies where HA-FCNs themselves functioned as single particle triggers in target imaging. The converted nanocrystal carbon particles from HA provide outstanding features for in vitro and in vivo new targeted delivery and diagnostic tools.This paper describes the in situ synthesis of single fluorescence carbon nanoparticles (FCNs) for target bioimaging applications derived from biocompatible hyaluronic acid (HA) without using common conjugation processes. FCNs formed via the dehydration of hyaluronic acid, which were obtained by carbonizing HA, and partially carbonized HA fluorescence carbon nanoparticles (HA-FCNs), formed by a lower degree of carbonization, show good aqueous solubility, small particle size (<20 nm) and different fluorescence intensities with a red shift. After confirming the cytotoxicity of HA-FCNs and FCNs, we carried out in vitro and in vivo bioimaging studies where HA-FCNs themselves functioned as single particle triggers in target imaging. The converted nanocrystal carbon particles from HA provide outstanding features for in vitro and in vivo new targeted delivery and diagnostic tools. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr07422j

Partial least squares analysis and mixture design for the study of the influence of composition variables on lipidic nanoparticle characteristics.

PubMed

Malzert-Fréon, A; Hennequin, D; Rault, S

2010-11-01

Lipidic nanoparticles (NP), formulated from a phase inversion temperature process, have been studied with chemometric techniques to emphasize the influence of the four major components (Solutol®, Labrasol®, Labrafac®, water) on their average diameter and their distribution in size. Typically, these NP present a monodisperse size lower than 200 nm, as determined by dynamic light scattering measurements. From the application of the partial least squares (PLS) regression technique to the experimental data collected during definition of the feasibility zone, it was established that NP present a core-shell structure where Labrasol® is well encapsulated and contributes to the structuring of the NP. Even if this solubility enhancer is regarded as a pure surfactant in the literature, it appears that the oil moieties of this macrogolglyceride mixture significantly influence its properties. Furthermore, results have shown that PLS technique can be also used for predictions of sizes for given relative proportions of components and it was established that from a mixture design, the quantitative mixture composition to use in order to reach a targeted size and a targeted polydispersity index (PDI) can be easily predicted. Hence, statistical models can be a useful tool to control and optimize the characteristics in size of NP. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Quantum dot-doped silica nanoparticles as probes for targeting of T-lymphocytes.

PubMed

Bottini, Massimo; D'Annibale, Federica; Magrini, Andrea; Cerignoli, Fabio; Arimura, Yutaka; Dawson, Marcia I; Bergamaschi, Enrico; Rosato, Nicola; Bergamaschi, Antonio; Mustelin, Tomas

2007-01-01

To enhance diagnostic or therapeutic efficacy, novel nanomaterials must be engineered to function in biologically relevant environments, be visible by conventional fluorescent microscopy, and have multivalent loading capacity for easy detection or effective drug delivery. Here we report the fabrication of silica nanoparticles doped with quantum dots and superficially functionalized with amino and phosphonate groups. The amino groups were acylated with a water-soluble biotin-labeling reagent. The biotinylated nanoparticles were subsequently decorated with neutravidin by exploiting the strong affinity between neutravidin and biotin. The resultant neutravidin-decorated fluorescent silica nanoparticles stably dispersed under physiological conditions, were visible by conventional optical and confocal fluorescent microscopy, and could be further functionalized with macromolecules, nucleic acids, and polymers. We also coated the surface of the nanoparticles with biotinylated mouse anti-human CD3 (alphaCD3). The resultant fluorescent nanoassembly was taken up by Jurkat T cells through receptor-mediated endocytosis and was partially released to lysosomes. Thus, quantum dot-doped silica nanoparticles decorated with neutravidin represent a potentially excellent scaffold for constructing specific intracellular nanoprobes and transporters.

Modifying the visual appearance of metal nanoparticle composites by infrared laser annealing

NASA Astrophysics Data System (ADS)

Halabica, Andrej; Indrobo, J. C.; Magruder, R. H., III; Haglund, R. F., Jr.; Epp, J. M.; Rashkeev, S.; Boatner, L. A.; Pennycook, S. J.; Pantelides, S. T.

2007-03-01

It has long been known that noble-metal nanoparticles in insulators can alter their visual appearance. Many metal nanoparticle composites can be created by ion implantation and subsequent annealing to initiate phase separation, nucleation and growth of nanoparticles. The size and size distribution of the nanoparticles - and therefore the color of the composite - are determined by the chemistry and thermodynamics of the annealing process. In this paper we report that we can also alter the color of gold- and silver-implanted silica and alumina by tunable infrared laser irradiation. Essentially a variant of rapid thermal annealing, this laser treatment can shift the plasmon band of the nanoparticles by tens of nm, resulting in significantly altered visual appearance. The amount of energy delivered to the implanted layer, and the subsequent color variation, can be adjusted by changing the wavelength and fluence of the laser. This makes it possible, as we will show, to write or pattern the composite material with 200 μm linewidths. This work is partially supported by DOE (DE-AC05-00OR22725), NSF (DMR-0513048), and by Alcoa Inc.

Gold Nanoparticles Stabilized with MPEG-Grafted Poly(l-lysine): in Vitro and in Vivo Evaluation of a Potential Theranostic Agent

PubMed Central

2015-01-01

As the number of diagnostic and therapeutic applications utilizing gold nanoparticles (AuNPs) increases, so does the need for AuNPs that are stable in vivo, biocompatible, and suitable for bioconjugation. We investigated a strategy for AuNP stabilization that uses methoxypolyethylene glycol-graft-poly(l-lysine) copolymer (MPEG-gPLL) bearing free amino groups as a stabilizing molecule. MPEG-gPLL injected into water solutions of HAuCl4 with or without trisodium citrate resulted in spherical (Zav = 36 nm), monodisperse (PDI = 0.27), weakly positively charged nanoparticles (AuNP3) with electron-dense cores (diameter: 10.4 ± 2.5 nm) and surface amino groups that were amenable to covalent modification. The AuNP3 were stable against aggregation in the presence of phosphate and serum proteins and remained dispersed after their uptake into endosomes. MPEG-gPLL-stabilized AuNP3 exhibited high uptake and very low toxicity in human endothelial cells, but showed a high dose-dependent toxicity in epithelioid cancer cells. Highly stable radioactive labeling of AuNP3 with 99mTc allowed imaging of AuNP3 biodistribution and revealed dose-dependent long circulation in the blood. The minor fraction of AuGNP3 was found in major organs and at sites of experimentally induced inflammation. Gold analysis showed evidence of a partial degradation of the MPEG-gPLL layer in AuNP3 particles accumulated in major organs. Radiofrequency-mediated heating of AuNP3 solutions showed that AuNP3 exhibited heating behavior consistent with 10 nm core nanoparticles. We conclude that PEG-pPLL coating of AuNPs confers “stealth” properties that enable these particles to exist in vivo in a nonaggregating, biocompatible state making them suitable for potential use in biomedical applications such as noninvasive radiofrequency cancer therapy. PMID:25496453

Pulmonary Nanoparticle Exposure Disrupts Systemic Microvascular Nitric Oxide Signaling

PubMed Central

Nurkiewicz, Timothy R.; Porter, Dale W.; Hubbs, Ann F.; Stone, Samuel; Chen, Bean T.; Frazer, David G.; Boegehold, Matthew A.; Castranova, Vincent

2009-01-01

We have shown that pulmonary nanoparticle exposure impairs endothelium dependent dilation in systemic arterioles. However, the mechanism(s) through which this effect occurs is/are unclear. The purpose of this study was to identify alterations in the production of reactive species and endogenous nitric oxide (NO) after nanoparticle exposure, and determine the relative contribution of hemoproteins and oxidative enzymes in this process. Sprague-Dawley rats were exposed to fine TiO2 (primary particle diameter ∼1 μm) and TiO2 nanoparticles (primary particle diameter ∼21 nm) via aerosol inhalation at depositions of 4–90 μg per rat. As in previous intravital experiments in the spinotrapezius muscle, dose-dependent arteriolar dilations were produced by intraluminal infusions of the calcium ionophore A23187. Nanoparticle exposure robustly attenuated these endothelium-dependent responses. However, this attenuation was not due to altered microvascular smooth muscle NO sensitivity because nanoparticle exposure did not alter arteriolar dilations in response to local sodium nitroprusside iontophoresis. Nanoparticle exposure significantly increased microvascular oxidative stress by ∼60%, and also elevated nitrosative stress fourfold. These reactive stresses coincided with a decreased NO production in a particle deposition dose-dependent manner. Radical scavenging, or inhibition of either myeloperoxidase or nicotinamide adenine dinucleotide phosphate oxidase (reduced) oxidase partially restored NO production as well as normal microvascular function. These results indicate that in conjunction with microvascular dysfunction, nanoparticle exposure also decreases NO bioavailability through at least two functionally distinct mechanisms that may mutually increase local reactive species. PMID:19270016

Current controversies and challenges in robotic-assisted, laparoscopic, and open partial nephrectomies.

PubMed

Laviana, Aaron A; Hu, Jim C

2014-06-01

Recent studies demonstrate that partial versus radical nephrectomy confers a survival advantage while lowering the risk of severe chronic kidney disease. Open partial nephrectomy remains the gold standard, but the use of minimally invasive approaches is expanding. Using a MEDLINE literature search, we reviewed all relevant literature between 2000 and 2014. Fifty-one articles were left for review after filtering for inclusion of trends, learning curve, perioperative outcomes, warm ischemia time, and costs. Partial nephrectomy use has increased over the past decade accounting for 24.7 % of all surgeries performed for the treatment of organ-confined renal masses in 2008. The introduction of robotic technology has continued to alter the landscape accounting for 47 % of all partial nephrectomies at academic US centers in 2011, though a center bias and publication bias likely exist. A slower adoption rate has been seen at non-academic centers and those in low-income areas. The learning curve for robotic-assisted laparoscopic nephrectomy has been shorter than for laparoscopic partial nephrectomy, explaining, in part, why the rate of partial nephrectomy remained relatively stagnant before the robotic-assisted laparoscopic nephrectomy, despite an increase in the detection of small renal masses. Operative and warm ischemia time remain shortest for open partial nephrectomy, though it is associated with the highest blood loss and longest hospital stay. Finally, open partial nephrectomy remains the least costly modality. Each approach to partial nephrectomy has its advantages and disadvantages, and continued effort must be applied to comparative effectiveness research for nephron-sparing treatments for renal cell carcinoma.

Physicochemical interaction mechanism between nanoparticles and tetrasaccharides (stachyose) during freeze-drying.

PubMed

Kamiya, Seitaro; Nakashima, Kenichiro

2017-12-01

Nanoparticle suspensions are thermodynamically unstable and subject to aggregation. Freeze-drying on addition of saccharides is a useful method for preventing aggregation. In the present study, tetrasaccharides (stachyose) was employed as an additive. In addition, we hypothesize the interactive mechanism between stachyose and the nanoparticles during freeze-drying for the first time. The mean particle size of the rehydrated freeze-dried stachyose-containing nanoparticles (104.7 nm) was similar to the initial particle size before freeze-drying (76.8 nm), indicating that the particle size had been maintained. The mean particle size of the rehydrated normal-dried stachyose-containing nanoparticles was 222.2 nm. The powder X-ray diffraction of the freeze-dried stachyose-containing nanoparticles revealed a halo pattern. The powder X-ray diffraction of the normally dried stachyose-containing nanoparticles produced mainly a halo pattern and a partial peak. These results suggest an interaction between the nanoparticles and stachyose, and that this relationship depends on whether the mixture is freeze-dried or dried normally. In the case of normal drying, although most molecules cannot move rapidly thereby settling irregularly, some stachyose molecules can arrange regularly leading to some degree of crystallization and potentially some aggregation. In contrast, during freeze-drying, the moisture sublimed, while the stachyose molecules and nanoparticles were immobilized in the ice. After sublimation, stachyose remained in the space occupied by water and played the role of a buffer material, thus preventing aggregation.

A resident conference for systems-based practice and practice-based learning.

PubMed

Sultana, Carmen J; Baxter, Jason K

2011-02-01

Improving patient safety and quality of care is part of systems-based practice and practice-based learning for residents. We expanded our obstetrics and gynecology department's regularly scheduled morbidity and mortality conferences to teach quality assurance concepts based on patient care on obstetrics and gynecology fourth-year resident rotations. Obstetrics and gynecology fourth-year residents on one of the two rotations each presented and analyzed a systems-based problem they encountered during patient care. They used an online learning module and proposed solutions, many of which were effectively implemented. Over 5 years, case presentations from 33 conferences were available with problems identified in emergency preparedness, coordination of care, scheduling and supervision, communication, medical practice, documentation, and lack of equipment or facilities. Twenty-two of the suggested solutions were partially or totally implemented. Barriers to implementation were identified. In conclusion, a conference presentation by fourth-year residents can identify patient safety problems, aid in their resolution, and suggest changes to patient care while teaching the principles of systems-based practice and practice-based learning.

Transport of Gold Nanoparticles by Vascular Endothelium from Different Human Tissues

PubMed Central

Gromnicova, Radka; Kaya, Mehmet; Romero, Ignacio A.; Williams, Phil; Satchell, Simon; Sharrack, Basil; Male, David

2016-01-01

The selective entry of nanoparticles into target tissues is the key factor which determines their tissue distribution. Entry is primarily controlled by microvascular endothelial cells, which have tissue-specific properties. This study investigated the cellular properties involved in selective transport of gold nanoparticles (<5 nm) coated with PEG-amine/galactose in two different human vascular endothelia. Kidney endothelium (ciGENC) showed higher uptake of these nanoparticles than brain endothelium (hCMEC/D3), reflecting their biodistribution in vivo. Nanoparticle uptake and subcellular localisation was quantified by transmission electron microscopy. The rate of internalisation was approximately 4x higher in kidney endothelium than brain endothelium. Vesicular endocytosis was approximately 4x greater than cytosolic uptake in both cell types, and endocytosis was blocked by metabolic inhibition, whereas cytosolic uptake was energy-independent. The cellular basis for the different rates of internalisation was investigated. Morphologically, both endothelia had similar profiles of vesicles and cell volumes. However, the rate of endocytosis was higher in kidney endothelium. Moreover, the glycocalyces of the endothelia differed, as determined by lectin-binding, and partial removal of the glycocalyx reduced nanoparticle uptake by kidney endothelium, but not brain endothelium. This study identifies tissue-specific properties of vascular endothelium that affects their interaction with nanoparticles and rate of transport. PMID:27560685

76 FR 64083 - Reliability Technical Conference; Notice of Technical Conference

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-17

... Technical Conference; Notice of Technical Conference Take notice that the Federal Energy Regulatory Commission will hold a Technical Conference on Tuesday, November 29, 2011, from 1 p.m. to 5 p.m. and... System. The conference will explore the progress made on the priorities for addressing risks to...

Altering Iron Oxide Nanoparticle Surface Properties Induce Cortical Neuron Cytotoxicity

PubMed Central

Rivet, Christopher J.; Yuan, Yuan; Borca-Tasciuc, Diana-Andra; Gilbert, Ryan J.

2014-01-01

Superparamagnetic iron oxide nanoparticles, with diameters in the range of a few tens of nanometers, display the ability to cross the blood-brain barrier and are envisioned as diagnostic and therapeutic tools in neuro-medicine. However, despite the numerous applications being explored, insufficient information is available on their potential toxic effect on neurons. While iron oxide has been shown to pose a decreased risk of toxicity, surface functionalization, often employed for targeted delivery, can significantly alter the biological response. This aspect is addressed in the present study, which investigates the response of primary cortical neurons to iron oxide nanoparticles with coatings frequently used in biomedical applications: aminosilane, dextran, and polydimethylamine. Prior to administering the particles to neuronal cultures, each particle type was thoroughly characterized to assess the (1) size of individual nanoparticles, (2) concentration of the particles in solution and (3) agglomeration size and morphology. Culture results show that polydimethylamine functionalized nanoparticles induce cell death at all concentrations tested by swift and complete removal of the plasma membrane. Aminosilane coated particles affected metabolic activity only at higher concentrations while leaving the membrane intact and dextran-coated nanoparticles partially altered viability at higher concentrations. These findings suggest that nanoparticle characterization and primary cell-based cytotoxicity evaluation should be completed prior to applying nanomaterials to the nervous system. PMID:22111864

Interfacing superhydrophobic silica nanoparticle films with graphene and thermoplastic polyurethane for wear/abrasion resistance.

PubMed

Naderizadeh, Sara; Athanassiou, Athanassia; Bayer, Ilker S

2018-06-01

Nanoparticle films are one of the most suitable platforms for obtaining sub-micrometer and nanometer dual-scale surface texture required for liquid repellency. The assembly of superhydrophobic nanoparticles into conformal and strongly adherent films having abrasion-induced wear resistance still poses a significant challenge. Various techniques have been developed over the years to render nanoparticle films with good liquid repellent properties and transparency. However, forming abrasion resistant superhydrophobic nanoparticle films on hard surfaces is challenging. One possibility is to partially embed or weld nanoparticles in thin thermoplastic primers applied over metals. Hexamethyldisilazane-functionalized fumed silica nanoparticle films spray deposited on aluminum surfaces were rendered abrasion resistant by thermally welding them into thermoplastic polyurethane (TPU) primer applied a priori over aluminum. Different solvents, nanoparticle concentrations and annealing temperatures were studied to optimize nanoparticle film morphology and hydrophobicity. Thermal annealing at 150 °C enhanced stability and wear resistance of nanoparticle films. A thin thermal interface layer of graphene nanoplatelets (GnPs) between the primer and the nanoparticle film significantly improved superhydrophobic wear resistance after annealing. As such, superhydrophobic nanocomposite films with the GnPs thermal interface layer displayed superior abrasion-induced wear resistance under 20 kPa compared to films having no GnPs-based thermal interface. Copyright © 2018 Elsevier Inc. All rights reserved.

Measuring nanoparticle diffusion in an ABELtrap

NASA Astrophysics Data System (ADS)

Dienerowitz, M.; Dienerowitz, F.; Börsch, M.

2018-03-01

Monitoring the Brownian motion of individual nanoscopic objects is key to investigate their transport properties and interactions with their close environment. Most techniques rely on transient diffusion through a detection volume or immobilisation, which restrict observation times or motility. We measure the diffusion coefficient and surface charge of individual nanoparticles and DNA molecules in an anti-Brownian electrokinetic trap (ABELtrap). This instrument is an active feedback trap confining the Brownian motion of a nanoparticle to the detection site by applying an electric field based on the particle’s current position. We simulate the Brownian motion of nanospheres in our sample geometry, including wall effects, due to partial confinement in the third dimension. The theoretically predicted values are in excellent agreement with our diffusion measurements in the ABELtrap. We also demonstrate the ABELtrap’s ability to measure varying sizes of DNA origami structures during denaturation.

Biotinylated vanadium and chromium sulfide nanoparticles as probes for colocalization of membrane proteins.

PubMed

Loukanov, Alexandre; Emin, Saim

2016-09-01

We report the microemulsion synthesis of vanadium and chromium sulfide nanoparticles (NPs) and their biological application as nanoprobes for colocalization of membrane proteins. Spherical V2 S3 and Cr2 S3 NPs were prepared in reverse microemulsion droplets, as nanoreactors, obtained by the surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in nonpolar organic phase (heptane). Electron microscopic data indicated that the size distribution of the nanoparticles was uniform with an average diameter between 3 ÷ 5 nm. The prepared hydrophobic nanocrystals were transferred in aqueous phase by surface cap exchange of AOT with biotin-dihydrolipoic ligands. This substitution allows the nanoparticles solubility in aqueous solutions and confer their bioactivity. In addition, we report the conjugation procedure between α-Lipoic acid (LA) and biotin (abbreviated as biotin-LA). The biotin-LA structure was characterized by 1D and 2D NMR spectroscopy. The biotinylated vanadium and chromium sulfide nanoparticles were tested as probes for colocalization of glutamate receptors on sodium-dodecyl-sulfate-digested replica prepared from rat hippocampus. The method suggests their high labeling efficiency for study of membrane biological macromolecules. Microsc. Res. Tech. 79:799-805, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Fourth International Conference: Modern Vaccines/Adjuvants Formulation--Impact on Future Development: May 15-17 2013, CHUV, Lausanne, Switzerland.

PubMed

Tupin, Emmanuel

2013-09-01

On the 15-17th of May 2013, about 120 scientists, postdoctoral fellows and professors representing renowned academic institutes and senior scientists and executives from small biotechs, contract research organizations (CROs) and Big Pharma companies, gathered at the Centre Hospitalier Universitaire Vaudois (CHUV) in Lausanne, Switzerland for the 4th international conference on Modern Vaccines and Adjuvants Formulation. Despite this relative small number, the speakers and attendees covered together a very broad field of expertise. Indeed, experts in microbiology, immunology, biochemistry, formulation, virus and nanoparticle characterization, vaccine production, quality control as well as regulatory professionals attended the conference and were able to present their works and discuss new developments within the field of vaccine and adjuvant development, characterization and approval process. This broad diversity was a highpoint of the conference and allowed for a stimulating environment and underlined the complexity of the challenges that the field currently faces in order to develop better or completely new vaccines and adjuvants.

Influence of the nanoparticles agglomeration state in the quantum-confinement effects: Experimental evidences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lorite, I., E-mail: lorite@physik.uni-leipzig.de; Division of Superconductivity and Magnetism, Faculty of Physics and Earth Sciences, Linnestrasse 5, D-04103 Leipzig; Romero, J. J.

2015-03-15

The agglomeration state facilitates particle-particle interaction which produces important effects in the phonon confinement effects at the nanoscale. A partial phonon transmission between close nanoparticles yields a lower momentum conservation relaxation than in a single isolated nanoparticle. It means a larger red shift and broadening of the Raman modes than the expected ones for Raman quantum confinement effects. This particle-particle interaction can drive to error when Raman responses are used to estimate the size of the nanoscaled materials. In this work different corrections are suggested to overtake this source of error.

Incorporation of a recombinant Eimeria maxima IMP1 antigen into nanoparticles confers protective immunity against E. Maxima challenge infection.

PubMed

Jenkins, Mark C; Stevens, Laura; O'Brien, Celia; Parker, Carolyn; Miska, Katrzyna; Konjufca, Vjollca

2018-02-14

The purpose of this study was to determine if conjugating a recombinant Eimeria maxima protein, namely EmaxIMP1, into 20 nm polystyrene nanoparticles (NP) could improve the level of protective immunity against E. maxima challenge infection. Recombinant EmaxIMP1 was expressed in Escherichia coli as a poly-His fusion protein, purified by NiNTA chromatography, and conjugated to 20 nm polystyrene NP (NP-EmaxIMP1). NP-EMaxIMP1 or control non-recombinant (NP-NR) protein were delivered per os to newly-hatched broiler chicks with subsequent booster immunizations at 3 and 21 days of age. In battery cage studies (n = 4), chickens immunized with NP-EMaxIMP1 displayed complete protection as measured by weight gain (WG) against E. maxima challenge compared to chickens immunized with NP-NR. WG in the NP-EMaxIMP1-immunized groups was identical to WG in chickens that were not infected with E. maxima infected chickens. In floor pen studies (n = 2), chickens immunized with NP-EMaxIMP1 displayed partial protection as measured by WG against E. maxima challenge compared to chickens immunized with NP-NR. In order to understand the basis for immune stimulation, newly-hatched chicks were inoculated per os with NP-EMaxIMP1 or NP-NR protein, and the small intestine, bursa, and spleen, were examined for NP localization at 1 h and 6 h post-inoculation. Within 1 h, both NP-EMaxIMP1 and NP-NR were observed in all 3 tissues. An increase was observed in the level of NP-EmaxIMP1 and NP-NR in all tissues at 6 h post-inoculation. These data indicate that 20 nm NP-EmaxIMP1 or NP-NR reached deeper tissues within hours of oral inoculation and elicited complete to partial immunity against E. maxima challenge infection. Published by Elsevier Ltd.

10 CFR 501.32 - Conferences (other than prepetition conferences).

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 4 2012-01-01 2012-01-01 false Conferences (other than prepetition conferences). 501.32 Section 501.32 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS ADMINISTRATIVE PROCEDURES AND SANCTIONS Written Comments, Public Hearings and Conferences During Administrative Proceedings § 501.32...

A new full-field interferometry approach for counting and differentiating aquatic biotic nanoparticles (Conference Presentation)

NASA Astrophysics Data System (ADS)

Boccara, A. Claude; Fedala, Yasmina; Voronkoff, Justine; Paffoni, Nina; Boccara, Martine

2017-03-01

Due to the huge abundance and the major role that viruses and membrane vesicles play in the seas or rivers ecosystems it is necessary to develop simple, sensitive, compact and reliable methods for their detection and characterization. Our approach is based on the measurement of the weak light level scattered by the biotic nanoparticles. We describe a new full-field, incoherently illuminated, shot-noise limited, common-path interferometric detection method coupled with the analysis of Brownian motion to detect, quantify, and differentiate biotic nanoparticles. The last developments take advantage of a new fast (700 Hz) camera with 2 Me- full well capacity that improves the signal to noise ratio and increases the precision of the Brownian motion characterization. We validated the method with calibrated nanoparticles and homogeneous DNA or RNA.viruses. The smallest virus size that we characterized with a suitable signal-to-noise ratio was around 30 nm in diameter with a target towards the numerous 20 nm diameter viruses. We show for the first time anisotropic trajectories for myoviruses meaning that there is a memory of the initial direction of their Brownian motions. Significant improvements have been made in the handling of the sample as well as in the statistical analysis for differentiating the various families of vesicles and virus. We further applied the method for vesicles detection and for analysis of coastal and oligotrophic samples from Tara Oceans circumnavigation as well of various rivers.

Fourth Bionanotox and Applications Research Conference, 2009

NASA Astrophysics Data System (ADS)

Camp, Judy

2010-04-01

"Anticipating the future" seemed the common challenge for scientists attending the 4th BioNanoTox and Applications Research Conference in Little Rock, AR, October 21-22, 2009. Over 50 participants in multi-disciplines such as biology, chemistry, physics, medicine, medical diagnostics, computer science and informatics, nanotechnology, toxicology, and pharmaceutical science gathered to share their research data. From topics on water and food resources to space exploration to conservation to understanding biological activities and using instruments and computers that process enormous data, participants shared research approaches from different fields to find common themes in this integrated field. Presentations aimed at preventing the harmful effects of scientific discoveries to animals, humans, plants, and environment; at controlling infections; and at optimizing health care. The conference included addresses from Thomas Flammang, PhD, of the Food and Drug Administration, National Center for Toxicological Research in Jefferson, AR; Little Rock City Mayor Mark Stodola; and two keynote speakers. Keynote lectures by Danuta Leszczynska, PhD, from the Department of Civil and Environmental Engineering, Interdisciplinary Nanotoxicity Center, in Jackson, MS, and by Keith Cowan, PhD, from the Institute for Environmental Biotechnology in Grahamstown, South Africa, highlighted current trends and future challenges of nanoparticle research and of bioprocess technologies. Additionally, 25 graduate and undergraduate students presented research posters, resulting in valuable discussion among the varied participants; three student projects were selected for awards.

Optical Properties and Microstructure of Silver-Copper Nanoparticles Synthesized by Pulsed Laser Deposition

NASA Astrophysics Data System (ADS)

Hirai, Makoto; Kumar, Ashok

2007-12-01

Utilizing a pulsed laser deposition (PLD) method, silver-copper (Ag-Cu) nanoparticles have been synthesized by changing the surface area ratio of the target ( S R = S Cu/( S Ag + S Cu)) from 0 to 30%. The peak absorption attributed to surface plasmon resonance (SPR) increased when increasing S R up to 15%, above which it decreased. The peak shifts seem to be induced by the changes in the conductivity and morphology of the Ag-Cu nanoparticles. Additionally, the interplanar spacings of the Ag-Cu nanoparticles prepared at S R = 15% corresponded to the Ag {111}, {200}, {220}, and Cu {111} planes. However, since the interplanar spacings attributed to the Cu {200} and {220} planes were not detected, the Ag-Cu nanoparticles were believed to possess a lattice constant ( a) close not to the Cu phase ( a = 3.615 Å) but to the Ag phase ( a = 4.086 Å). Moreover, confirming the presence of Cu atoms in the nanoparticles using energy dispersive X-ray (EDX) spectra, Ag-Cu nanoparticles may be a solid solution in which Cu atoms partially replace Ag atoms in the fcc structure.

Satellite Conferences

Science.gov Websites

NOAA- NESDIS Banner Satellite Conferences Collage images of earth, POES and GOES satellites in space HOME Call for Poster Abstracts DOC Logo NOAA Logo Satellite Conferences Welcome to the website for National Oceanic and Atmospheric Administration (NOAA) Satellite Conferences; past, present and future

Synthesis of Multifunctional Nanoparticles for Cancer Diagnostics and Therapeutics

NASA Astrophysics Data System (ADS)

Fang, Chen

2011-12-01

Magnetic nanoparticles (MNPs) have attracted enormous research attention due to their unique magnetic properties that enable the detection by the non-invasive medical imaging modality---magnetic resonance imaging (MRI). By incorporating advanced features, such as specific targeting, multimodality, therapeutic delivery, the detectability and applicability of MNPs have been dramatically expanded. Smart and rational design on structure, composition and surface chemistry is essential to achieving desired properties in MNP systems, such as high sensitivity and colloidal stability, target specificity and/or multimodality. The goal of this research is to develop MNP-based platforms for the detection, diagnosis and treatment of cancer. MNPs with high contrast enhancement were coated with poly(ethylene glycol) (PEG)-based polymers to render aqueous stability and confer therapeutic-loading capability. Tumor-specific MNPs were developed by functionalization of nanoparticles with chlorotoxin (CTX) or arginine-glycine-aspartic acid (RGD) that targets, respectively, MMP-2 receptor or alphavbeta3 integrin overexpressed on a variety of cancer cells. The effects of ligands' molecular targets on the temporal and spatial distribution of MNPs within tumors were also investigated both in vitro and in vivo. All MNPs exhibited excellent long-term stability in cell culture media. CTX-labeled MNP exhibited sustained accumulation, penetration and distribution in the tumor mass. These findings revealed the influence of the targeting ligands on the intratumoral distribution of the ligand-enabled nanoprobes. To demonstrate the ability of nanoparticles as drug carrier, anthracyline chemotherapeutic drugs doxorubicin and mitoxantrone were attached to iron oxide nanoparticles. The theragnostic nanoparticles showed sufficient contrast enhancement and comparable anti-neoplastic efficacy in vitro. With flexible surface chemistry, our nanoparticle platform can be used in a modular fashion to

Antibodies generated by immunization with the NS1 protein of West Nile virus confer partial protection against lethal Japanese encephalitis virus challenge.

PubMed

Sun, EnCheng; Zhao, Jing; TaoYang; Xu, QingYuan; Qin, YongLi; Wang, WenShi; Wei, Peng; Wu, DongLai

2013-09-27

Japanese encephalitis virus (JEV) and West Nile virus (WNV) are two medically important flaviviruses that can cause severe hemorrhagic and encephalitic diseases in humans. Immune responses directed against the NS1 protein of flaviviruses can confer protection against lethal viral challenge. Previous studies have shown that the WNV NS1 protein harbors epitopes that elicit antibodies that cross react with JEV. Here we demonstrate that the WNV NS1 protein not only contains cross-reactive epitopes, but that the antibodies elicited by these cross-reactive epitopes provide partial protection against lethal JEV challenge in a mouse model. Mice immunized with WNV NS1 protein showed reduced morbidity and mortality following both intracerebral and intraperitoneal JEV challenge. WNV NS1 immunization attenuated the extent of lung pathology generated following JEV challenge, and delayed the appearance of other pathological findings including vascular cuffing. By screening and identifying the specific WNV NS1 protein-derived peptides recognized by serum antibodies elicited by immunization with WNV NS1 protein and by JEV challenge, we found after JEV challenge will induce several new epitopes, but which epitope primarily contribute to antibody-mediated cross protection need further evaluation. The knowledge and reagents generated in this study have potential applications in vaccine and subunit vaccine development for WNV and JEV. Copyright © 2013 Elsevier B.V. All rights reserved.

Nanoparticles for Radiation Therapy Enhancement: the Key Parameters

PubMed Central

Retif, Paul; Pinel, Sophie; Toussaint, Magali; Frochot, Céline; Chouikrat, Rima; Bastogne, Thierry; Barberi-Heyob, Muriel

2015-01-01

This review focuses on the radiosensitization strategies that use high-Z nanoparticles. It does not establish an exhaustive list of the works in this field but rather propose constructive criticisms pointing out critical factors that could improve the nano-radiation therapy. Whereas most reviews show the chemists and/or biologists points of view, the present analysis is also seen through the prism of the medical physicist. In particular, we described and evaluated the influence of X-rays energy spectra using a numerical analysis. We observed a lack of standardization in preclinical studies that could partially explain the low number of translation to clinical applications for this innovative therapeutic strategy. Pointing out the critical parameters of high-Z nanoparticles radiosensitization, this review is expected to contribute to a larger preclinical and clinical development. PMID:26155318

Nanoparticles for Radiation Therapy Enhancement: the Key Parameters.

PubMed

Retif, Paul; Pinel, Sophie; Toussaint, Magali; Frochot, Céline; Chouikrat, Rima; Bastogne, Thierry; Barberi-Heyob, Muriel

2015-01-01

This review focuses on the radiosensitization strategies that use high-Z nanoparticles. It does not establish an exhaustive list of the works in this field but rather propose constructive criticisms pointing out critical factors that could improve the nano-radiation therapy. Whereas most reviews show the chemists and/or biologists points of view, the present analysis is also seen through the prism of the medical physicist. In particular, we described and evaluated the influence of X-rays energy spectra using a numerical analysis. We observed a lack of standardization in preclinical studies that could partially explain the low number of translation to clinical applications for this innovative therapeutic strategy. Pointing out the critical parameters of high-Z nanoparticles radiosensitization, this review is expected to contribute to a larger preclinical and clinical development.

Electrokinetic motion of a rectangular nanoparticle in a nanochannel

NASA Astrophysics Data System (ADS)

Movahed, Saeid; Li, Dongqing

2012-08-01

This article presents a theoretical study of electrokinetic motion of a negatively charged cubic nanoparticle in a three-dimensional nanochannel with a circular cross-section. Effects of the electrophoretic and the hydrodynamic forces on the nanoparticle motion are examined. Because of the large applied electric field over the nanochannel, the impact of the Brownian force is negligible in comparison with the electrophoretic and the hydrodynamic forces. The conventional theories of electrokinetics such as the Poisson-Boltzmann equation and the Helmholtz-Smoluchowski slip velocity approach are no longer applicable in the small nanochannels. In this study, and at each time step, first, a set of highly coupled partial differential equations including the Poisson-Nernst-Plank equation, the Navier-Stokes equations, and the continuity equation was solved to find the electric potential, ionic concentration field, and the flow field around the nanoparticle. Then, the electrophoretic and hydrodynamic forces acting on the negatively charged nanoparticle were determined. Following that, the Newton second law was utilized to find the velocity of the nanoparticle. Using this model, effects of surface electric charge of the nanochannel, bulk ionic concentration, the size of the nanoparticle, and the radius of the nanochannel on the nanoparticle motion were investigated. Increasing the bulk ionic concentration or the surface charge of the nanochannel will increase the electroosmotic flow, and hence affect the particle's motion. It was also shown that, unlike microchannels with thin EDL, the change in nanochannel size will change the EDL field and the ionic concentration field in the nanochannel, affecting the particle's motion. If the nanochannel size is fixed, a larger particle will move faster than a smaller particle under the same conditions.

Size Control of Porous Silicon-Based Nanoparticles via Pore-Wall Thinning.

PubMed

Secret, Emilie; Leonard, Camille; Kelly, Stefan J; Uhl, Amanda; Cozzan, Clayton; Andrew, Jennifer S

2016-02-02

Photoluminescent silicon nanocrystals are very attractive for biomedical and electronic applications. Here a new process is presented to synthesize photoluminescent silicon nanocrystals with diameters smaller than 6 nm from a porous silicon template. These nanoparticles are formed using a pore-wall thinning approach, where the as-etched porous silicon layer is partially oxidized to silica, which is dissolved by a hydrofluoric acid solution, decreasing the pore-wall thickness. This decrease in pore-wall thickness leads to a corresponding decrease in the size of the nanocrystals that make up the pore walls, resulting in the formation of smaller nanoparticles during sonication of the porous silicon. Particle diameters were measured using dynamic light scattering, and these values were compared with the nanocrystallite size within the pore wall as determined from X-ray diffraction. Additionally, an increase in the quantum confinement effect is observed for these particles through an increase in the photoluminescence intensity of the nanoparticles compared with the as-etched nanoparticles, without the need for a further activation step by oxidation after synthesis.

Freezing polystyrene-b-poly(2-vinylpyridine) micelle nanoparticles with different nanostructures and sizes.

PubMed

Fan, Hailong; Jin, Zhaoxia

2014-04-28

Herein we report how to control the nanostructures and sizes of polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) nanoparticles via manipulating freezing in solvent-exchange. By characterizing and analyzing the distinct structural features of the obtained nanoparticles, we recognized that micelle self-assembly happens in the precipitation of PS-b-P2VP when water is added into the block copolymer (BCP) solution. Solvent properties significantly influence micelle types that are vesicles in acetone/H2O and spherical micelles in tetrahydrofuran/H2O, respectively, thus further inducing different frozen nanostructures of the obtained nanoparticles, onion-like in acetone/H2O and large compound micelles in tetrahydrofuran/H2O. By changing the concentration of the block copolymers and the Vsolvent/VH2O ratio to modify the freezing stage at which block copolymer micelles are frozen, we can further control the size of the nanoparticles. Moreover, small molecules (phosphotungstic acid, pyrene, 1-pyrenebutyric acid) can be trapped into the block copolymer nanoparticles via the freezing process. Their distribution in the nanoparticles relies not only on the solvent property, but also on their interactions with block copolymers. The hybrid nanoparticles with ordered distribution of small molecules can be further changed to partially-void nanoparticles. Our study demonstrated that manipulating the freezing of block copolymers in the solvent exchange process is a simple and controllable fabrication method to generate BCP nanoparticles with different architectures.

Interfacial functionalization and engineering of nanoparticles

NASA Astrophysics Data System (ADS)

Song, Yang

nanoparticles in the formation of functional nanocomposites. Part of the dissertation research was also devoted to graphene quantum dots (GQDs)-supported platinum (Pt/G) nanoparticles and their electrocatalytic activity in oxygen reduction reaction. These Pt/G nanocomposites were prepared by a hydrothermal procedure at controlled temperatures. Spectroscopic measurements based on FTIR, Raman and XPS confirmed the formation of various oxygenated structural defects on GQDs and the variation of their concentrations with the hydrothermal conditions. Interestingly, electrocatalytic activity of GQD/Pt composites exhibited a volcano-shaped variation with the GQD structural defects, with the best identified as the samples prepared at 160 °C for 6 h where the mass activity was found to meet the DOE target for 2015. This remarkable performance was accounted for by the deliberate manipulation of the adsorption of oxygen and reaction intermediates on platinum by the GQD structural defects through partial charge transfer. The strategy presented herein may offer a new paradigm in the design and engineering of nanoparticle catalysts for fuel cell electrochemistry. In addition, studies were also carried out to study intervalence charge transfer between ferrocenyl moieties bonded on carbon nanoparticle surfaces by diazonium reaction. Electrochemical studies exhibited two pairs of voltammetric waves with a difference of their formal potentials at about 78 mV, suggesting nanoparticle-mediated intraparticle charge delocalization at mixed valence as a result of the strong core-ligand covalent bonds and the conductive sp 2 carbon matrix of the graphitic cores. Consistent behaviors were observed in near-infrared measurements, indicating that the particles behaved analogously to a Class I/II mixed-valence compound.

Emission quenching of magnetic dipole transitions near an absorbing nanoparticle (Conference Presentation)

NASA Astrophysics Data System (ADS)

Chigrin, Dmitry N.; Kumar, Deepu; von Plessen, Gero

2016-09-01

Emission quenching is analysed at nanometer distances from the surface of an absorbing nanoparticle. It is demonstrated that emission quenching at small distances to the surface is much weaker for magnetic-dipole (MD) than for electric-dipole (ED) transitions. This difference is explained by the fact that the electric field induced by a magnetic dipole has a weaker distance dependence than the electric field of an electric dipole. It is also demonstrated that in the extreme near-field regime the non-locality of the optical response of the metal results in additional emission quenching for both ED and MD transitions.

PREFACE: Wake Conference 2015

NASA Astrophysics Data System (ADS)

Barney, Andrew; Nørkær Sørensen, Jens; Ivanell, Stefan

2015-06-01

The 44 papers in this volume constitute the proceedings of the 2015 Wake Conference, held in Visby on the island of Gotland in Sweden. It is the fourth time this conference has been held. The Wake Conference series started in Visby, where it was held in 2009 and 2011. In 2013 it took place in Copenhagen where it was combined with the International Conference on Offshore Wind Energy and Ocean Energy. In 2015 it is back where it started in Visby, where it takes place at Uppsala University Campus Gotland, June 9th-11th. The global yearly production of electrical energy by wind turbines has grown tremendously in the past decade and it now comprises more than 3% of the global electrical power consumption. Today the wind power industry has a global annual turnover of more than 50 billion USD and an annual average growth rate of more than 20%. State-of-the-art wind turbines have rotor diameters of up to 150 m and 8 MW installed capacity. These turbines are often placed in large wind farms that have a total production capacity corresponding to that of a nuclear power plant. In order to make a substantial impact on one of the most significant challenges of our time, global warming, the industry's growth has to continue for a decade or two yet. This in turn requires research into the physics of wind turbine wakes and wind farms. Modern wind turbines are today clustered in wind farms in which the turbines are fully or partially influenced by the wake of upstream turbines. As a consequence, the wake behind the wind turbines has a lower mean wind speed and an increased turbulence level, as compared to the undisturbed flow outside the farm. Hence, wake interaction results in decreased total production of power, caused by lower kinetic energy in the wind, and an increase in the turbulence intensity. Therefore, understanding the physical nature of the vortices and their dynamics in the wake of a turbine is important for the optimal design of a wind farm. This conference is aimed

3D Bragg coherent diffractive imaging of five-fold multiply twinned gold nanoparticle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jong Woo; Ulvestad, Andrew; Manna, Sohini

The formation mechanism of five-fold multiply twinned nanoparticles has been a long-term topic because of their geometrical incompatibility. So, various models have been proposed to explain how the internal structure of the multiply twinned nanoparticles accommodates the constraints of the solid-angle deficiency. Here, we investigate the internal structure, strain field and strain energy density of 600 nm sized five-fold multiply twinned gold nanoparticles quantitatively using Bragg coherent diffractive imaging, which is suitable for the study of buried defects and three-dimensional strain distribution with great precision. Our study reveals that the strain energy density in five-fold multiply twinned gold nanoparticles ismore » an order of magnitude higher than that of the single nanocrystals such as an octahedron and triangular plate synthesized under the same conditions. This result indicates that the strain developed while accommodating an angular misfit, although partially released through the introduction of structural defects, is still large throughout the crystal.« less

3D Bragg coherent diffractive imaging of five-fold multiply twinned gold nanoparticle

DOE PAGES

Kim, Jong Woo; Ulvestad, Andrew; Manna, Sohini; ...

2017-08-11

The formation mechanism of five-fold multiply twinned nanoparticles has been a long-term topic because of their geometrical incompatibility. So, various models have been proposed to explain how the internal structure of the multiply twinned nanoparticles accommodates the constraints of the solid-angle deficiency. Here, we investigate the internal structure, strain field and strain energy density of 600 nm sized five-fold multiply twinned gold nanoparticles quantitatively using Bragg coherent diffractive imaging, which is suitable for the study of buried defects and three-dimensional strain distribution with great precision. Our study reveals that the strain energy density in five-fold multiply twinned gold nanoparticles ismore » an order of magnitude higher than that of the single nanocrystals such as an octahedron and triangular plate synthesized under the same conditions. This result indicates that the strain developed while accommodating an angular misfit, although partially released through the introduction of structural defects, is still large throughout the crystal.« less

Thrombin-inhibiting perfluorocarbon nanoparticles provide a novel strategy for treatment and magnetic resonance imaging of acute thrombosis

PubMed Central

Myerson, J.; He, L.; Lanza, G.; Tollefsen, D.; Wickline, S.

2013-01-01

Background As a regulator of the penultimate step in the coagulation cascade, thrombin represents a principal target of direct and specific anticoagulants. Objective A potent thrombin inhibitor complexed with a colloidal nanoparticle was devised as a first-in-class anticoagulant with prolonged and highly localized therapeutic impact conferred by its multivalent thrombin-absorbing particle surface. Methods PPACK (Phe(D)-Pro-Arg-Chloromethylketone) was secured covalently to the surface of perfluorocarbon-core nanoparticle structures. PPACK and PPACK nanoparticle inhibition of thrombin were assessed in vitro via thrombin activity against a chromogenic substrate. In vivo antithrombotic activity of PPACK, heparin, non-functionalized nanoparticles, and PPACK nanoparticles was assessed through IV administration prior to acute photochemical injury of the common carotid artery. Perfluorocarbon particle retention in extracted carotid arteries from injured mice was assessed via 19F magnetic resonance spectroscopy (MRS) and imaging (MRI) at 11.7 T. APTT measurements determined the systemic effects of the PPACK nanoparticles at various times after injection. Results Optical assay verified that PPACK nanoparticles exceeded PPACK’s intrinsic activity against thrombin. Application of the an in vivo acute arterial thrombosis model demonstrated that PPACK nanoparticles outperformed both heparin (p=.001) and uncomplexed PPACK (p=.0006) in inhibiting thrombosis. 19F MRS confirmed that PPACK nanoparticles specifically bound to sites of acute thrombotic injury. APTT normalized within twenty minutes of PPACK nanoparticles injection. Conclusions PPACK nanoparticles present thrombin-inhibiting surfaces at sites of acutely forming thrombi that continue to manifest local clot inhibition even as systemic effects rapidly diminish and thus represent a new platform for localized control of acute thrombosis. PMID:21605330

Imposed Environmental Stresses Facilitate Cell-Free Nanoparticle Formation by Deinococcus radiodurans

PubMed Central

2017-01-01

ABSTRACT The biological synthesis of metal nanoparticles has been examined in a wide range of organisms, due to increased interest in green synthesis and environmental remediation applications involving heavy metal ion contamination. Deinococcus radiodurans is particularly attractive for environmental remediation involving metal reduction, due to its high levels of resistance to radiation and other environmental stresses. However, few studies have thoroughly examined the relationships between environmental stresses and the resulting effects on nanoparticle biosynthesis. In this work, we demonstrate cell-free nanoparticle production and study the effects of metal stressor concentrations and identity, temperature, pH, and oxygenation on the production of extracellular silver nanoparticles by D. radiodurans R1. We also report the synthesis of bimetallic silver and gold nanoparticles following the addition of a metal stressor (silver or gold), highlighting how production of these particles is enabled through the application of environmental stresses. Additionally, we found that both the morphology and size of monometallic and bimetallic nanoparticles were dependent on the environmental stresses imposed on the cells. The nanoparticles produced by D. radiodurans exhibited antimicrobial activity comparable to that of pure silver nanoparticles and displayed catalytic activity comparable to that of pure gold nanoparticles. Overall, we demonstrate that biosynthesized nanoparticle properties can be partially controlled through the tuning of applied environmental stresses, and we provide insight into how their application may affect nanoparticle production in D. radiodurans during bioremediation. IMPORTANCE Biosynthetic production of nanoparticles has recently gained prominence as a solution to rising concerns regarding increased bacterial resistance to antibiotics and a desire for environmentally friendly methods of bioremediation and chemical synthesis. To date, a range of

Imposed Environmental Stresses Facilitate Cell-Free Nanoparticle Formation by Deinococcus radiodurans.

PubMed

Chen, Angela; Contreras, Lydia M; Keitz, Benjamin K

2017-09-15

The biological synthesis of metal nanoparticles has been examined in a wide range of organisms, due to increased interest in green synthesis and environmental remediation applications involving heavy metal ion contamination. Deinococcus radiodurans is particularly attractive for environmental remediation involving metal reduction, due to its high levels of resistance to radiation and other environmental stresses. However, few studies have thoroughly examined the relationships between environmental stresses and the resulting effects on nanoparticle biosynthesis. In this work, we demonstrate cell-free nanoparticle production and study the effects of metal stressor concentrations and identity, temperature, pH, and oxygenation on the production of extracellular silver nanoparticles by D. radiodurans R1. We also report the synthesis of bimetallic silver and gold nanoparticles following the addition of a metal stressor (silver or gold), highlighting how production of these particles is enabled through the application of environmental stresses. Additionally, we found that both the morphology and size of monometallic and bimetallic nanoparticles were dependent on the environmental stresses imposed on the cells. The nanoparticles produced by D. radiodurans exhibited antimicrobial activity comparable to that of pure silver nanoparticles and displayed catalytic activity comparable to that of pure gold nanoparticles. Overall, we demonstrate that biosynthesized nanoparticle properties can be partially controlled through the tuning of applied environmental stresses, and we provide insight into how their application may affect nanoparticle production in D. radiodurans during bioremediation. IMPORTANCE Biosynthetic production of nanoparticles has recently gained prominence as a solution to rising concerns regarding increased bacterial resistance to antibiotics and a desire for environmentally friendly methods of bioremediation and chemical synthesis. To date, a range of organisms

Biogenic selenium nanoparticles: current status and future prospects.

PubMed

Wadhwani, Sweety A; Shedbalkar, Utkarsha U; Singh, Richa; Chopade, Balu A

2016-03-01

Selenium nanoparticles (SeNPs) are gaining importance in the field of medicine owing to their antibacterial and anticancer properties. SeNPs are biocompatible and non-toxic compared to the counterparts, selenite (SeO3 (-2)) and selenate (SeO4 (-2)). They can be synthesized by physical, chemical, and biological methods and have distinct bright orange-red color. Biogenic SeNPs are stable and do not aggregate owing to natural coating of the biomolecules. Various hypotheses have been proposed to describe the mechanism of microbial synthesis of SeNPs. It is primarily a two-step reduction process from SeO4 (-2) to SeO3 (-2) to insoluble elemental selenium (Se(0)) catalyzed by selenate and selenite reductases. Phenazine-1-carboxylic acid and glutathione are involved in selenite reduction. Se factor A (SefA) and metalloid reductase Rar A present on the surface of SeNPs confer stability to the nanoparticles. SeNPs act as potent chemopreventive and chemotherapeutic agents. Conjugation with antibiotics enhances their anticancer efficacy. These also have applications in nanobiosensors and environmental remediation.

Microwave-assisted synthesis of iron oxide nanoparticles in biocompatible organic environment

NASA Astrophysics Data System (ADS)

Aivazoglou, E.; Metaxa, E.; Hristoforou, E.

2018-04-01

The development of magnetite and maghemite particles in uniform nanometer size has triggered the interest of the research community due to their many interesting properties leading to a wide range of applications, such as catalysis, nanomedicine-nanobiology and other engineering applications. In this study, a simple, time-saving and low energy-consuming, microwave-assisted synthesis of iron oxide nanoparticles, is presented. The nanoparticles were prepared by microwave-assisted synthesis using polyethylene glycol (PEG) or PEG and β-cyclodextrin (β-CD)/water solutions of chloride salts of iron in the presence of ammonia solution. The prepared nano-powders were characterized using X-Ray Diffraction (XRD), Transition Electron Microscopy (TEM), Fourier-transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Vibrating Sample Magnetometer (VSM), X-Ray Photoelectron Spectroscopy (XPS) and Thermal analysis (TG/DSC). The produced nanoparticles are crystallized mostly in the magnetite and maghemite lattice exhibiting very similar shape and size, with indications of partial PEG coating. Heating time, microwave power and presence of PEG, are the key factors shaping the size properties of nanoparticles. The average size of particles ranges from 10.3 to 19.2 nm. The nanoparticles exhibit a faceted morphology, with zero contamination levels. The magnetic measurements indicate that the powders are soft magnetic materials with negligible coercivity and remanence, illustrating super-paramagnetic behavior.

Electron magnetic resonance and magnetooptical studies of nanoparticle-containing borate glasses

NASA Astrophysics Data System (ADS)

Kliava, Janis; Edelman, Irina; Ivanova, Oxana; Ivantsov, Ruslan; Petrakovskaja, Eleonora; Hennet, Louis; Thiaudière, Dominique; Saboungi, Marie-Louise

2011-03-01

We report electron magnetic resonance (EMR) and magnetooptical studies of borate glasses of molar composition 22.5K 2O-22.5Al 2O 3-55B 2O 3 co-doped with low concentrations of Fe 2O 3 and MnO. In as-prepared samples the paramagnetic ions, as a rule, are in diluted state. However, in the case where the ratio of the iron and manganese oxides in the charge is 3/2, magnetic nanoparticles with characteristics close to those of manganese ferrite are formed already at the first stage of the glass preparation, as evidenced by both magnetic circular dichroism (MCD) and EMR. After thermal treatment all glasses show characteristic MCD and EMR spectra, attesting to the presence of magnetic nanoparticles, predominantly including iron ions. Preliminary EXAFS measurements at the Fe K-absorption edge show an emergence of nanoparticles with a structure close to MnFe 2O 4 after annealing the glasses at 560 °C. By computer simulating the EMR spectra at variable temperatures, a superparamagnetic nature of relatively broad size and shape distribution with the average diameter of ca. 3-4 nm. The characteristic temperature-dependent shift of the apparent resonance field is explained by a strong temperature dependence of the magnetic anisotropy in the nanoparticles. The formation of magnetic nanoparticles confers to the potassium-alumina-borate glasses magnetic and magneto-optical properties typical of magnetically ordered substances. At the same time, they remain transparent in a part of the visible and near infrared spectral range and display a high Faraday rotation value.

Porous metals from sintering of nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cappillino, Patrick J.; Robinson, David B.

A method including encapsulating or capping metallic nanoparticles by a dendrimer or a polymer with binding sites for metal particless or metal ions dispersed in a fluid; modifying the fluid to disrupt the interaction of the dendrimer or polymer with the particles; and subsequently or concomitantly sintering or partially consolidating the zero valent metal. A method including introducing a first metal salt and a second metal salt into a dendrimer or a polymer with binding sites for metals or metal ions; reducing a metal ion of the first metal salt to a zero valent first metal and a metal ionmore » of the second metal salt to a zero valend second metal; disrupting an interaction between the dendrimer or the polymer and the first metal and the second metal; and sintering or partially consolidating the first metal and the second metal.« less

From well-defined Pt(II) surface species to the controlled growth of silica supported Pt nanoparticles.

PubMed

Laurent, Pierre; Veyre, Laurent; Thieuleux, Chloé; Donet, Sébastien; Copéret, Christophe

2013-01-07

Silica-supported Pt nanoparticles were prepared from well-defined surface platinum(II) surface species, obtained by grafting of well-defined Pt(II) molecular precursors with specific ligands (Cl, Me, N(SiMe(3))(2), OSi(OtBu)(3)) onto silica partially dehydroxylated at 200 and 700 °C yielding well-defined platinum(II) surface species. This approach allowed for testing the effect of Pt density and ligands on nanoparticle size. Higher grafting densities are achieved on silica partially dehydroxylated at 200 °C due to its initially higher surface silanol density. Surface species have been synthesized from symmetrical and dissymmetrical complexes, namely (COD)Pt(Me)(2), (COD)Pt(OSi(OtBu)(3))(2), (COD)Pt(Me)(OSi(OtBu)(3)), (COD)Pt(Me)(N(SiMe(3))(2)), (COD)Pt(Cl)(N(SiMe(3))(2)) and (COD)Pt(N(SiMe(3))(2))(OSi(OtBu)(3)) yielding mono-grafted complexes of general formula (COD)Pt(R)(OSi≡) according to elemental analyses, diffuse reflectance infrared fourier transform (DRIFT) and carbon-13 solid-state nuclear magnetic resonance (NMR) spectroscopies. While the dimethyl-complex shows low reactivity towards grafting, bis-siloxy and dissymmetric complexes demonstrate better reactivity yielding platinum loadings up to 7.4 wt%. Upon grafting amido complexes, the surface passivation yielding Me(3)SiOSi≡ surface species is demonstrated. Nanoparticles have been synthesized from these well-defined surface species by reduction under H(2) at 300 °C, under static or flow conditions. This process yields nanoparticles with sizes ranging from 2 to 3.3 nm and narrow size dispersion from 0.5 to 1.2 nm. Interestingly, the chloride complex yields large nanoparticles from 5 to 40 nm demonstrating the strong influence of chloride over the nanoparticles growth.

Antimicrobial Effect of Biocompatible Silicon Nanoparticles Activated Using Therapeutic Ultrasound.

PubMed

Shevchenko, Svetlana N; Burkhardt, Markus; Sheval, Eugene V; Natashina, Ulyana A; Grosse, Christina; Nikolaev, Alexander L; Gopin, Alexander V; Neugebauer, Ute; Kudryavtsev, Andrew A; Sivakov, Vladimir; Osminkina, Liubov A

2017-03-14

In this study, we report a method for the suppression of Escherichia coli (E. coli) vitality by means of therapeutic ultrasound irradiation (USI) using biocompatible silicon nanoparticles as cavitation sensitizers. Silicon nanoparticles without (SiNPs) and with polysaccharide (dextran) coating (DSiNPs) were used. Both types of nanoparticles were nontoxic to Hep 2 cells up to a concentration of 2 mg/mL. The treatment of bacteria with nanoparticles and application of 1 W/cm 2 USI resulted in the reduction of their viabilities up to 35 and 72% for SiNPs and DSiNPs, respectively. The higher bacterial viability reduction for DSiNPs as compared with SiNPs can be explained by the fact that the biopolymer shell of the polysaccharide provides a stronger adhesion of nanoparticles to the bacterial surface. Transmission electron microscopy (TEM) studies showed that the bacterial lipid shell was partially perforated after the combined treatment of DSiNPs and USI, which can be explained by the lysis of bacterial membrane due to the cavitation sensitized by the SiNPs. Furthermore, we have shown that 100% inhibition of E. coli bacterial colony growth is possible by coupling the treatments of DSiNPs and USI with an increased intensity of up to 3 W/cm 2 . The observed results reveal the application of SiNPs as promising antimicrobial agents.

Modulating interactions between ligand-coated nanoparticles and phase-separated lipid bilayers by varying the ligand density and the surface charge.

PubMed

Chen, Xiaojie; Tieleman, D Peter; Liang, Qing

2018-02-01

The interactions between nanoparticles and lipid bilayers are critical in applications of nanoparticles in nanomedicine, cell imaging, toxicology, and elsewhere. Here, we investigate the interactions between nanoparticles coated with neutral and/or charged ligands and phase-separated lipid bilayers using coarse-grained molecular dynamics simulation. Both penetration and adsorption processes as well as the final distribution of the nanoparticles can be readily modulated by varying the ligand density and the surface charge of the nanoparticles. Completely hydrophobic (neutral) nanoparticles with larger size initially preferentially penetrate into the liquid-disordered region of the lipid bilayer and finally transfer into the liquid-ordered region; partially hydrophilic nanoparticles with low or moderate surface charge tend to either distribute in the liquid-disordered region or be adsorbed on the surface of the lipid bilayer, while strongly hydrophilic nanoparticles with high surface charge always reside on the surface of the lipid bilayer. Interactions of the nanoparticles with the lipid bilayers are affected by the surface charge of nanoparticles, hydrophobic mismatch, bending of the ligands, and the packing state of the lipids. Insight in these factors can be used to improve the efficiency of designing nanoparticles for specific applications.

Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Honghu; Nayak, Srikanth; Wang, Wenjie

Here, we report on pH- and salt-responsive assembly of nanoparticles capped with polyelectrolytes at vapor–liquid interfaces. Two types of alkylthiol-terminated poly(acrylic acid) (PAAs, varying in length) are synthesized and used to functionalize gold nanoparticles (AuNPs) to mimic similar assembly effects of single-stranded DNA-capped AuNPs using synthetic polyelectrolytes. Using surface-sensitive X-ray scattering techniques, including grazing incidence small-angle X-ray scattering (GISAXS) and X-ray reflectivity (XRR), we demonstrate that PAA-AuNPs spontaneously migrate to the vapor–liquid interfaces and form Gibbs monolayers by decreasing the pH of the suspension. The Gibbs monoalyers show chainlike structures of monoparticle thickness. The pH-induced self-assembly is attributed to themore » protonation of carboxyl groups and to hydrogen bonding between the neighboring PAA-AuNPs. In addition, we show that adding MgCl 2 to PAA-AuNP suspensions also induces adsorption at the interface and that the high affinity between magnesium ions and carboxyl groups leads to two- and three-dimensional clusters that yield partial surface coverage and poorer ordering of NPs at the interface. We also examine the assembly of PAA-AuNPs in the presence of a positively charged Langmuir monolayer that promotes the attraction of the negatively charged capped NPs by electrostatic forces. Our results show that synthetic polyelectrolyte-functionalized nanoparticles exhibit interfacial self-assembly behavior similar to that of DNA-functionalized nanoparticles, providing a pathway for nanoparticle assembly in general.« less

Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles

DOE PAGES

Zhang, Honghu; Nayak, Srikanth; Wang, Wenjie; ...

2017-10-06

Here, we report on pH- and salt-responsive assembly of nanoparticles capped with polyelectrolytes at vapor–liquid interfaces. Two types of alkylthiol-terminated poly(acrylic acid) (PAAs, varying in length) are synthesized and used to functionalize gold nanoparticles (AuNPs) to mimic similar assembly effects of single-stranded DNA-capped AuNPs using synthetic polyelectrolytes. Using surface-sensitive X-ray scattering techniques, including grazing incidence small-angle X-ray scattering (GISAXS) and X-ray reflectivity (XRR), we demonstrate that PAA-AuNPs spontaneously migrate to the vapor–liquid interfaces and form Gibbs monolayers by decreasing the pH of the suspension. The Gibbs monoalyers show chainlike structures of monoparticle thickness. The pH-induced self-assembly is attributed to themore » protonation of carboxyl groups and to hydrogen bonding between the neighboring PAA-AuNPs. In addition, we show that adding MgCl 2 to PAA-AuNP suspensions also induces adsorption at the interface and that the high affinity between magnesium ions and carboxyl groups leads to two- and three-dimensional clusters that yield partial surface coverage and poorer ordering of NPs at the interface. We also examine the assembly of PAA-AuNPs in the presence of a positively charged Langmuir monolayer that promotes the attraction of the negatively charged capped NPs by electrostatic forces. Our results show that synthetic polyelectrolyte-functionalized nanoparticles exhibit interfacial self-assembly behavior similar to that of DNA-functionalized nanoparticles, providing a pathway for nanoparticle assembly in general.« less

Acid-Responsive Therapeutic Polymer for Prolonging Nanoparticle Circulation Lifetime and Destroying Drug-Resistant Tumors.

PubMed

Piao, Ji-Gang; Gao, Feng; Yang, Lihua

2016-01-13

How to destroy drug-resistant tumor cells remains an ongoing challenge for cancer treatment. We herein report on a therapeutic nanoparticle, aHLP-PDA, which has an acid-activated hemolytic polymer (aHLP) grafted onto photothermal polydopamine (PDA) nanosphere via boronate ester bond, in efforts to ablate drug-resistant tumors. Upon exposure to oxidative stress and/or near-infrared laser irradiation, aHLP-PDA nanoparticle responsively releases aHLP, likely via responsive cleavage of boronate ester bond, and thus responsively exhibits acid-facilitated mammalian-membrane-disruptive activity. In vitro cell studies with drug-resistant and/or thermo-tolerant cancer cells show that the aHLP-PDA nanoparticle demonstrates preferential cytotoxicity at acidic pH over physiological pH. When administered intravenously, the aHLP-PDA nanoparticle exhibits significantly prolonged blood circulation lifetime and enhanced tumor uptake compared to bare PDA nanosphere, likely owing to aHLP's stealth effects conferred by its zwitterionic nature at blood pH. As a result, the aHLP-PDA nanoparticle effectively ablates drug-resistant tumors, leading to 100% mouse survival even on the 32nd day after suspension of photothermal treatment, as demonstrated with the mouse model. This work suggests that a combination of nanotechnology with lessons learned in bacterial antibiotic resistance may offer a feasible and effective strategy for treating drug-resistant cancers often found in relapsing patients.

Exchange bias effect in Au-Fe 3O 4 dumbbell nanoparticles induced by the charge transfer from gold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feygenson, Mikhail; Bauer, John C; Gai, Zheng

2015-08-10

We have studied the origin of the exchange bias effect in the Au-Fe 3O 4 dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe 3O 4 nanoparticles (9.8 nm). The magnetization, small-angle neutron scattering, synchrotron x-ray diffraction and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wüstite phase within Fe 3O 4 nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe 3O 4 is giving rise to the exchange bias effect. The strength of the exchange bias fieldsmore » depends on the interfacial area and lattice mismatch between both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe 3O 4 into FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed across the interface to accommodate an excess of oxygen released during the reduction of magnetite.« less

Exchange bias effect in Au-Fe3O4 dumbbell nanoparticles induced by the charge transfer from gold

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feygenson, Mikhail; Bauer, John C.; Gai, Zheng

2015-08-10

We have studied the origin of the exchange bias effect in the Au-Fe3O4 dumbbell nanoparticles in two samples with different sizes of the Au seed nanoparticles (4.1 and 2.7 nm) and same size of Fe3O4 nanoparticles (9.8 nm). The magnetization, small-angle neutron-scattering, synchrotron x-ray diffraction, and scanning transmission electron microscope measurements determined the antiferromagnetic FeO wustite phase within Fe3O4 nanoparticles, originating at the interface with the Au nanoparticles. The interface between antiferromagnetic FeO and ferrimagnetic Fe3O4 is giving rise to the exchange bias effect. The strength of the exchange bias fields depends on the interfacial area and lattice mismatch betweenmore » both phases. We propose that the charge transfer from the Au nanoparticles is responsible for a partial reduction of the Fe3O4 into the FeO phase at the interface with Au nanoparticles. The Au-O bonds are formed, presumably across the interface to accommodate an excess of oxygen released during the reduction of magnetite« less

PREFACE: International Conference "Trends in Spintronics and Nanomagnetism" (TSN-2010)

NASA Astrophysics Data System (ADS)

Maruccio, Giuseppe; Sanvito, Stefano; Hoffmann, Germar; Wiesendanger, Roland; Rowan, Alan

2011-03-01

Conference banner The International Conference "Trends in Spintronics and Nanomagnetism" (TSN-2010), was organized by partners of the EU-project SpiDME and held in the historical city of Lecce, Italy from 23-27 May 2010, at the Ecotekne Campus, University of Salento. The conference provided an international forum to discuss recent progress and future trends in the field. In particular, the aim was to bring together the community of more conventional spin-transport, with that of molecular and nano-magnetism. The main topics of TSN-2010 were: MATERIALSSPIN-PHYSICS AND THEORY - Molecular Magnets- Spin injection - Magnetic nanoparticles and nanowires- Domain walls, spin torque and vortex dynamics - Magnetic semiconductors- Numerical modeling of organic nanomagnetism - Multiferroics and transition metal oxides APPLICATIONSADVANCES IN CHARACTERIZATION - Magnetic Multilayers- Magneto-optical characterization and spin manipulation - Spin-photonics- Intrinsic spin transport mechanism in organics - Molecular and nano-spintronics- Organometallic molecules on surfaces - Spin-based quantum computation- Single molecular magnets on surfaces - Magnetism for sensing and nanomedicine- Nanoscale characterization and spin-sensitive SPM The scientific programme started on Monday 24 May and ended on Thursday 27 May. The Nobel Laureate A Fert attended the conference giving a plenary talk and the programme also featured invited presentations by (in alphabetical order): M Aeschlimann, M Affronte, N Atodiresei, P A Bobbert, A Dediu, N Kioussis, L W Molenkamp, J Moodera, V Prigodin, M Ruben, R Sessoli, R Tan, and H Wende. TSN2010 had 150 attendees who came from around the globe to present their latest research in 100 oral presentations. Contributed talks were selected by the program committee, composed of Giuseppe Maruccio, Ross Rinaldi, Valentina Arima, Fabio Della Sala, Maurizio Martino (Universitá del Salento, NNL Institute Nanoscience-CNR, Lecce, Italy), Stefano Sanvito (Trinity College

Tissue distribution and excretion kinetics of orally administered silica nanoparticles in rats

PubMed Central

Lee, Jeong-A; Kim, Mi-Kyung; Paek, Hee-Jeong; Kim, Yu-Ri; Kim, Meyoung-Kon; Lee, Jong-Kwon; Jeong, Jayoung; Choi, Soo-Jin

2014-01-01

Purpose The effects of particle size on the tissue distribution and excretion kinetics of silica nanoparticles and their biological fates were investigated following a single oral administration to male and female rats. Methods Silica nanoparticles of two different sizes (20 nm and 100 nm) were orally administered to male and female rats, respectively. Tissue distribution kinetics, excretion profiles, and fates in tissues were analyzed using elemental analysis and transmission electron microscopy. Results The differently sized silica nanoparticles mainly distributed to kidneys and liver for 3 days post-administration and, to some extent, to lungs and spleen for 2 days post-administration, regardless of particle size or sex. Transmission electron microscopy and energy dispersive spectroscopy studies in tissues demonstrated almost intact particles in liver, but partially decomposed particles with an irregular morphology were found in kidneys, especially in rats that had been administered 20 nm nanoparticles. Size-dependent excretion kinetics were apparent and the smaller 20 nm particles were found to be more rapidly eliminated than the larger 100 nm particles. Elimination profiles showed 7%–8% of silica nanoparticles were excreted via urine, but most nanoparticles were excreted via feces, regardless of particle size or sex. Conclusion The kidneys, liver, lungs, and spleen were found to be the target organs of orally-administered silica nanoparticles in rats, and this organ distribution was not affected by particle size or animal sex. In vivo, silica nanoparticles were found to retain their particulate form, although more decomposition was observed in kidneys, especially for 20 nm particles. Urinary and fecal excretion pathways were determined to play roles in the elimination of silica nanoparticles, but 20 nm particles were secreted more rapidly, presumably because they are more easily decomposed. These findings will be of interest to those seeking to predict

Physicochemical properties of surface charge-modified ZnO nanoparticles with different particle sizes

PubMed Central

Kim, Kyoung-Min; Choi, Mun-Hyoung; Lee, Jong-Kwon; Jeong, Jayoung; Kim, Yu-Ri; Kim, Meyoung-Kon; Paek, Seung-Min; Oh, Jae-Min

2014-01-01

In this study, four types of standardized ZnO nanoparticles were prepared for assessment of their potential biological risk. Powder-phased ZnO nanoparticles with different particle sizes (20 nm and 100 nm) were coated with citrate or L-serine to induce a negative or positive surface charge, respectively. The four types of coated ZnO nanoparticles were subjected to physicochemical evaluation according to the guidelines published by the Organisation for Economic Cooperation and Development. All four samples had a well crystallized Wurtzite phase, with particle sizes of ∼30 nm and ∼70 nm after coating with organic molecules. The coating agents were determined to have attached to the ZnO surfaces through either electrostatic interaction or partial coordination bonding. Electrokinetic measurements showed that the surface charges of the ZnO nanoparticles were successfully modified to be negative (about −40 mV) or positive (about +25 mV). Although all the four types of ZnO nanoparticles showed some agglomeration when suspended in water according to dynamic light scattering analysis, they had clearly distinguishable particle size and surface charge parameters and well defined physicochemical properties. PMID:25565825

Transformation-Dissolution Reactions Partially Explain Adverse Effects of Metallic Silver Nanoparticles to Soil Nitrification in Different Soils.

PubMed

Bollyn, Jessica; Willaert, Bernd; Kerré, Bart; Moens, Claudia; Arijs, Katrien; Mertens, Jelle; Leverett, Dean; Oorts, Koen; Smolders, Erik

2018-04-25

Risk assessment of metallic nanoparticles (NP) is critically affected by the concern that toxicity goes beyond that of the metallic ion. This study addressed this concern for soils with silver (Ag)-NP using the Ag-sensitive nitrification assay. Three agricultural soils (A,B,C) were spiked with equivalent Ag doses of either Ag-NP (d = 13 nm) or AgNO 3 . Soil solution was isolated and monitored over 97 days with due attention to accurate Ag fractionation at low (∼10 µg L -1 ) Ag concentrations. Truly dissolved (<1 kDa) Ag in the AgNO 3 -amended soils decreased with reaction half-lives of 4 to 22 days depending on the soil, denoting important Ag-ageing reactions. In contrast, truly dissolved Ag in Ag-NP-amended soils first increased by dissolution and subsequently decreased by ageing; the concentration never exceeding that in the AgNO 3 -amended soils. The half-lives of Ag-NP transformation-dissolution were about 4 days (soils A&B) and 36 days (soil C). The Ag toxic thresholds (EC10, mg Ag kg -1 soil) of nitrification, either evaluated at 21 or 35 days after spiking, were similar between the two Ag forms (soils A&B) but were factors 3 to 8 lower for AgNO 3 than for Ag-NP (soil C), largely corroborating with dissolution differences. This fate and bio-assay showed that Ag-NPs are not more toxic than AgNO 3 at equivalent total soil Ag concentrations and that differences in Ag-dissolution at least partially explain toxicity differences between the forms and among soils. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Carbon nanoparticle doped micro-patternable nano-composites for wearable sensing applications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Khosla, Ajit

2017-04-01

This talk focuses on preparation, characterization and micropatterning of electrically conducting KETJENBLACK carbon black nanoparticle (80 nm-diameter) doped Polydimethylsiloxane (PDMS) by employing extrusion mixing. Previously, we had reported fabrication of various micropatternable nanocomposites for wearable sensing applications vis solvent assisted ultrasonic mixing technique[1-16] . Extrusion mixing has an advantage as no organic solvents are used and homogenous dispersion of carbon nanoparticles is observed, which is confirmed by SEM analysis. The developed nanocomposite can be micropatterened using standard microfabrication techniques. It is also observed that percolation threshold occurs at 0.51 wt% of carbon nanoparticles in polymer matrix. Examples of developed nano-composites for wearable sensing applications for precision medicine will also be discussed. References: 1.http://summit.sfu.ca/item/12017 A. Khosla. Micropatternable multifunctional nanocomposite polymers for flexible soft MEMS applications. Diss. Applied Science: School of Engineering Science, 2011. 2. A. Khosla ; B. L. Gray; Fabrication of multiwalled carbon nanotube polydimethylsiloxne nanocomposite polymer flexible microelectrodes for microfluidics and MEMS. Proc. SPIE 7642, Electroactive Polymer Actuators and Devices (EAPAD) 2010, 76421V (April 09, 2010); doi:10.1117/12.847292. 3. Ang Li ; Ajit Khosla ; Connie Drewbrook ; Bonnie L. Gray; Fabrication and testing of thermally responsive hydrogel-based actuators using polymer heater elements for flexible microvalves. Proc. SPIE 7929, Microfluidics, BioMEMS, and Medical Microsystems IX, 79290G (February 14, 2011); doi:10.1117/12.873197. 4. Khosla, A. and Gray, B. L. (2010), Preparation, Micro-Patterning and Electrical Characterization of Functionalized Carbon-Nanotube Polydimethylsiloxane Nanocomposite Polymer. Macromol. Symp., 297: 210-218. doi:10.1002/masy.200900165 5. A. Khosla ; D. Hilbich ; C. Drewbrook ; D. Chung ; B. L. Gray; Large

Emerging applications of nanoparticles for lung cancer diagnosis and therapy

NASA Astrophysics Data System (ADS)

Sukumar, Uday Kumar; Bhushan, Bharat; Dubey, Poornima; Matai, Ishita; Sachdev, Abhay; Packirisamy, Gopinath

2013-07-01

Lung cancer is by far the leading cause of cancer-related mortality worldwide, most of them being active tobacco smokers. Non small cell lung cancer accounts for around 85% to 90% of deaths, whereas the rest is contributed by small cell lung cancer. The extreme lethality of lung cancer arises due to lack of suitable diagnostic procedures for early detection of lung cancer and ineffective conventional therapeutic strategies. In course with desperate attempts to address these issues independently, a multifunctional nanotherapeutic or diagnostic system is being sought as a favorable solution. The manifestation of physiochemical properties of such nanoscale systems is tuned favorably to come up with a versatile cancer cell targeted diagnostic and therapeutic system. Apart from this, the aspect of being at nanoscale by itself confers the system with an advantage of passive accumulation at the site of tumor. This review provides a broad perspective of three major subclasses of such nanoscale therapeutic and diagnostic systems which include polymeric nanoparticles-based approaches, metal nanoparticles-based approaches, and bio-nanoparticles-based approaches. This review work also serves the purpose of gaining an insight into the pros and cons of each of these approaches with a prospective improvement in lung cancer therapeutics and diagnostics.

Nanospace-Mediated Self-Organization of Nanoparticles in Flexible Porous Polymer Templates.

PubMed

Kuroda, Yoshiyuki; Muto, Itaru; Shimojima, Atsushi; Wada, Hiroaki; Kuroda, Kazuyuki

2017-09-12

Self-organization is a fundamental process for the construction of complex hierarchically ordered nanostructures, which are widespread in biological systems. However, precise control of size, shape, and surface properties is required for self-organization of nanoparticles. Here, we demonstrate a novel self-organization phenomenon mediated by flexible nanospaces in templates. Inorganic nanoparticles (e.g., silica, zirconia, and titania) are deposited in porous polymer thin films with randomly distributed pores on the surface, leaving a partially filled nanospace in each pore. Heating at temperatures beyond the glass transition temperature of the template leads to self-organization of the inorganic nanoparticles into one-dimensional chainlike networks. The self-organization is mediated by the deformation and fusion of the residual nanospaces, and it can be rationally controlled by sequential heat treatments. These results show that a nanospace, defined by the nonexistence of matter, interacts indirectly with matter and can be used as a component of self-organization systems.

Determination of anisotropy constants of protein encapsulated iron oxide nanoparticles by electron magnetic resonance

NASA Astrophysics Data System (ADS)

Li, Hongyan; Klem, Michael T.; Sebby, Karl B.; Singel, David J.; Young, Mark; Douglas, Trevor; Idzerda, Yves U.

2009-02-01

Angle-dependent electron magnetic resonance was performed on 4.9, 8.0, and 19 nm iron oxide nanoparticles encapsulated within protein capsids and suspended in water. Measurements were taken at liquid nitrogen temperature after cooling in a 1 T field to partially align the particles. The angle dependence of the shifts in the resonance field for the iron oxide nanoparticles (synthesized within Listeria-Dps, horse spleen ferritin, and cowpea chlorotic mottle virus) all show evidence of a uniaxial anisotropy. Using a Boltzmann distribution for the particles' easy-axis direction, we are able to use the resonance field shifts to extract a value for the anisotropy energy, showing that the anisotropy energy density increases with decreasing particle size. This suggests that surface anisotropy plays a significant role in magnetic nanoparticles of this size.

EGFR-targeted gelatin nanoparticles for systemic administration of gemcitabine in an orthotopic pancreatic cancer model.

PubMed

Singh, Amit; Xu, Jing; Mattheolabakis, George; Amiji, Mansoor

2016-04-01

In this study, we have formulated redox-responsive epidermal growth factor receptor (EGFR)-targeted type B gelatin nanoparticles as a targeted vector for systemic delivery of gemcitabine therapy in pancreatic cancer. The gelatin nanoparticles were formed by ethanol-induced desolvation process to encapsulate the bound drug. The surface of the nanoparticles was decorated either with poly(ethylene glycol) (PEG) chains to impart enhanced circulation time or with EGFR targeting peptide to confer target specificity. Our in vitro studies in Panc-1 human pancreatic ductal adenocarcinoma cells confirm that gemcitabine encapsulated in EGFR-targeted gelatin nanoparticles, released through disulfide bond cleavage, had a significantly improved cytotoxic profile. Further, the in vivo anticancer activity was evaluated in an orthotopic pancreatic adenocarcinoma tumor bearing SCID beige mice, which confirmed that EGFR-targeted gelatin nanoparticles could efficiently deliver gemcitabine to the tumor leading to higher therapeutic benefit as compared to the drug in solution. The treatment of pancreatic cancer remains unsatisfactory, with an average 5-year survival of less than 5%. New treatment modalities are thus urgently needed. In this study, the authors presented their formulation of redox-responsive epidermal growth factor receptor (EGFR)-targeted type B gelatin nanoparticles as a carrier for gemcitabine. In-vitro and in-vivo experiments showed encouraging results. It is hoped that the findings would provide a novel and alternative drug delivery platform for the future. Copyright © 2015 Elsevier Inc. All rights reserved.

Measurement of nanoparticle size, suspension polydispersity, and stability using near-field optical trapping and light scattering (Conference Presentation)

NASA Astrophysics Data System (ADS)

Schein, Perry; O'Dell, Dakota; Erickson, David

2017-02-01

Nanoparticles are becoming ubiquitous in applications including diagnostic assays, drug delivery and therapeutics. However, there remain challenges in the quality control of these products. Here we present methods for the orthogonal measurement of these parameters by tracking the motion of the nanoparticle in all three special dimensions as it interacts with an optical waveguide. These simultaneous measurements from a single particle basis address some of the gaps left by current measurement technologies such as nanoparticle tracking analysis, ζ-potential measurements, and absorption spectroscopy. As nanoparticles suspended in a microfluidic channel interact with the evanescent field of an optical waveguide, they experience forces and resulting motion in three dimensions: along the propagation axis of the waveguide (x-direction) they are propelled by the optical forces, parallel to the plane of the waveguide and perpendicular to the optical propagation axis (y-direction) they experience an optical gradient force generated from the waveguide mode profile which confines them in a harmonic potential well, and normal to the surface of the waveguide they experience an exponential downward optical force balanced by the surface interactions that confines the particle in an asymmetric well. Building on our Nanophotonic Force Microscopy technique, in this talk we will explain how to simultaneously use the motion in the y-direction to estimate the size of the particle, the comparative velocity in the x-direction to measure the polydispersity of a particle population, and the motion in the z-direction to measure the potential energy landscape of the interaction, providing insight into the colloidal stability.

Targeting to carcinoma cells with chitosan- and starch-coated magnetic nanoparticles for magnetic hyperthermia.

PubMed

Kim, Dong-Hyun; Kim, Kyoung-Nam; Kim, Kwang-Mahn; Lee, Yong-Keun

2009-01-01

The delivery of hyperthermic thermoseeds to a specific target site with minimal side effects is an important challenge in targeted hyperthermia, which employs magnetic method and functional polymers. An external magnetic field is used to control the site-specific targeting of the magnetic nanoparticles. Polymer-coated magnetic nanoparticles can confer a higher affinity to the biological cell membranes. In this study, uncoated, chitosan-coated, and starch-coated magnetic nanoparticles were synthesized for use as a hyperthermic thermoseed. Each sample was examined with respect to their applications to hyperthermia using XRD, VSM, and FTIR. In addition, the temperature changes under an alternating magnetic field were observed. As in vitro tests, the magnetic responsiveness of chitosan- and starch-coated magnetite was determined by a simple blood vessel model under various intensities of magnetic field. L929 normal cells and KB carcinoma cells were used to examine the cytotoxicity and affinity of each sample using the MTT method. The chitosan-coated magnetic nanoparticles generated a higher DeltaT of 23 degrees C under an AC magnetic field than the starch-coated magnetite, and the capturing rate of the particles was 96% under an external magnetic field of 0.4 T. The highest viability of L929 cells was 93.7%. Comparing the rate of KB cells capture with the rate of L929 cells capture, the rate of KB cells capture relatively increased with 10.8% in chitosan-coated magnetic nanoparticles. Hence, chitosan-coated magnetic nanoparticles are biocompatible and have a selective affinity to KB cells. The targeting of magnetic nanoparticles in hyperthermia was improved using a controlled magnetic field and a chitosan-coating. Therefore, chitosan-coated magnetic nanoparticles are expected to be promising materials for use in magnetic targeted hyperthermia. 2008 Wiley Periodicals, Inc.

Preparation and characterization of 6-mercaptopurine-coated magnetite nanoparticles as a drug delivery system.

PubMed

Dorniani, Dena; Hussein, Mohd Zobir Bin; Kura, Aminu Umar; Fakurazi, Sharida; Shaari, Abdul Halim; Ahmad, Zalinah

2013-01-01

Iron oxide nanoparticles are of considerable interest because of their use in magnetic recording tape, ferrofluid, magnetic resonance imaging, drug delivery, and treatment of cancer. The specific morphology of nanoparticles confers an ability to load, carry, and release different types of drugs. We synthesized superparamagnetic nanoparticles containing pure iron oxide with a cubic inverse spinal structure. Fourier transform infrared spectra confirmed that these Fe3O4 nanoparticles could be successfully coated with active drug, and thermogravimetric and differential thermogravimetric analyses showed that the thermal stability of iron oxide nanoparticles coated with chitosan and 6-mercaptopurine (FCMP) was markedly enhanced. The synthesized Fe3O4 nanoparticles and the FCMP nanocomposite were generally spherical, with an average diameter of 9 nm and 19 nm, respectively. The release of 6-mercaptopurine from the FCMP nanocomposite was found to be sustained and governed by pseudo-second order kinetics. In order to improve drug loading and release behavior, we prepared a novel nanocomposite (FCMP-D), ie, Fe3O4 nanoparticles containing the same amounts of chitosan and 6-mercaptopurine but using a different solvent for the drug. The results for FCMP-D did not demonstrate "burst release" and the maximum percentage release of 6-mercaptopurine from the FCMP-D nanocomposite reached about 97.7% and 55.4% within approximately 2,500 and 6,300 minutes when exposed to pH 4.8 and pH 7.4 solutions, respectively. By MTT assay, the FCMP nanocomposite was shown not to be toxic to a normal mouse fibroblast cell line. Iron oxide coated with chitosan containing 6-mercaptopurine prepared using a coprecipitation method has the potential to be used as a controlled-release formulation. These nanoparticles may serve as an alternative drug delivery system for the treatment of cancer, with the added advantage of sparing healthy surrounding cells and tissue.

Effects of Particle Hydrophobicity, Surface Charge, Media pH Value and Complexation with Human Serum Albumin on Drug Release Behavior of Mitoxantrone-Loaded Pullulan Nanoparticles

PubMed Central

Tao, Xiaojun; Jin, Shu; Wu, Dehong; Ling, Kai; Yuan, Liming; Lin, Pingfa; Xie, Yongchao; Yang, Xiaoping

2015-01-01

We prepared two types of cholesterol hydrophobically modified pullulan nanoparticles (CHP) and carboxyethyl hydrophobically modified pullulan nanoparticles (CHCP) substituted with various degrees of cholesterol, including 3.11, 6.03, 6.91 and 3.46 per polymer, and named CHP−3.11, CHP−6.03, CHP−6.91 and CHCP−3.46. Dynamic laser light scattering (DLS) showed that the pullulan nanoparticles were 80–120 nm depending on the degree of cholesterol substitution. The mean size of CHCP nanoparticles was about 160 nm, with zeta potential −19.9 mV, larger than CHP because of the carboxyethyl group. A greater degree of cholesterol substitution conferred greater nanoparticle hydrophobicity. Drug-loading efficiency depended on nanoparticle hydrophobicity, that is, nanoparticles with the greatest degree of cholesterol substitution (6.91) showed the most drug encapsulation efficiency (90.2%). The amount of drug loading increased and that of drug release decreased with enhanced nanoparticle hydrophobicity. Nanoparticle surface-negative charge disturbed the amount of drug loading and drug release, for an opposite effect relative to nanoparticle hydrophobicity. The drug release in pullulan nanoparticles was higher pH 4.0 than pH 6.8 media. However, the changed drug release amount was not larger for negative-surface nanoparticles than CHP nanoparticles in the acid release media. Drug release of pullulan nanoparticles was further slowed with human serum albumin complexation and was little affected by nanoparticle hydrophobicity and surface negative charge. PMID:28344259

Immunological correlates for protection against intranasal challenge of Bacillus anthracis spores conferred by a protective antigen-based vaccine in rabbits.

PubMed

Weiss, Shay; Kobiler, David; Levy, Haim; Marcus, Hadar; Pass, Avi; Rothschild, Nili; Altboum, Zeev

2006-01-01

Correlates between immunological parameters and protection against Bacillus anthracis infection in animals vaccinated with protective antigen (PA)-based vaccines could provide surrogate markers to evaluate the putative protective efficiency of immunization in humans. In previous studies we demonstrated that neutralizing antibody levels serve as correlates for protection in guinea pigs (S. Reuveny et al., Infect. Immun. 69:2888-2893, 2001; H. Marcus et al., Infect. Immun. 72:3471-3477, 2004). In this study we evaluated similar correlates for protection by active and passive immunization of New Zealand White rabbits. Full immunization and partial immunization were achieved by single and multiple injections of standard and diluted doses of a PA-based vaccine. Passive immunization was carried out by injection of immune sera from rabbits vaccinated with PA-based vaccine prior to challenge with B. anthracis spores. Immunized rabbits were challenged by intranasal spore instillation with one of two virulent strains (strains Vollum and ATCC 6605). The immune competence was estimated by measuring the level of total anti-PA antibodies, the neutralizing antibody titers, and the conferred protective immunity. The results indicate that total anti-PA antibody titers greater than 1 x 10(5) conferred protection, whereas lower titers (between 10(4) and 10(5)) provided partial protection but failed to predict protection. Neutralizing antibody titers between 500 and 800 provided partial protection, while titers higher than 1,000 conferred protection. In conclusion, this study emphasizes that regardless of the immunization regimen or the time of challenge, neutralizing antibody titers are better predictors of protection than total anti-PA titers.

Nanomaterials and nanoparticles: sources and toxicity.

PubMed

Buzea, Cristina; Pacheco, Ivan I; Robbie, Kevin

2007-12-01

understanding the toxicity of nanoparticles is that their minute size, smaller than cells and cellular organelles, allows them to penetrate these basic biological structures, disrupting their normal function.Examples of toxic effects include tissue inflammation, and altered cellular redox balance toward oxidation, causing abnormal function or cell death. The manipulation of matter at the scale of atoms,"nanotechnology," is creating many new materials with characteristics not always easily predicted from current knowledge. Within the nearly limitless diversity of these materials, some happen to be toxic to biological systems, others are relatively benign, while others confer health benefits. Some of these materials have desirable characteristics for industrial applications, as nanostructured materials often exhibit beneficial properties, from UV absorbance in sunscreen to oil-less lubrication of motors.A rational science-based approach is needed to minimize harm caused by these materials, while supporting continued study and appropriate industrial development. As current knowledge of the toxicology of "bulk" materials may not suffice in reliably predicting toxic forms of nanoparticles,ongoing and expanded study of "nanotoxicity" will be necessary. For nanotechnologies with clearly associated health risks, intelligent design of materials and devices is needed to derive the benefits of these new technologies while limiting adverse health impacts. Human exposure to toxic nanoparticles can be reduced through identifying creation-exposure pathways of toxins, a study that may someday soon unravel the mysteries of diseases such as Parkinson's and Alzheimer's. Reduction in fossil fuel combustion would have a large impact on global human exposure to nanoparticles, as would limiting deforestation and desertification.While nanotoxicity is a relatively new concept to science, this review reveals the result of life's long history of evolution in the presence of nanoparticles, and how the

Conference Model: Guidelines...for Science Supervisors on How to Conduct a Successful Leadership Conference.

ERIC Educational Resources Information Center

DeBlasi, Robert V.

Guidelines of a four-phase model for conducting leadership conferences are outlined. Phase I focuses on initial conference planning, including (1) identifying need and purpose for the conference; (2) selecting a conference chairperson; (3) forming the conference planning committee, listing suggested committees and their responsibilities (program,…

Conference Support, 23rd Western Photosynthesis Conference 2014, Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wachter, Rebekka

The Western Photosynthesis Conference is a regional conference that is held on an annual basis to bring together researchers primarily from the Western United States to share their newest research advances on photosynthetic processes. The 23rd conference was focused on both fundamental and more applied research on the biological conversion of solar energy to various energy storage forms. Several particular areas of solar energy conversion were emphasized in this conference (see below). Some of these topics, such as carbon limitations on photosynthesis, biomimicry and phenotyping, have traditionally not been incorporated extensively in the Western Photosynthesis Conference. We found that thesemore » topics have substantially broadened of the scope of this meeting.« less

Convection-Enhanced Delivery of Carboplatin PLGA Nanoparticles for the Treatment of Glioblastoma.

PubMed

Arshad, Azeem; Yang, Bin; Bienemann, Alison S; Barua, Neil U; Wyatt, Marcella J; Woolley, Max; Johnson, Dave E; Edler, Karen J; Gill, Steven S

2015-01-01

We currently use Convection-Enhanced Delivery (CED) of the platinum-based drug, carboplatin as a novel treatment strategy for high grade glioblastoma in adults and children. Although initial results show promise, carboplatin is not specifically toxic to tumour cells and has been associated with neurotoxicity at high infused concentrations in pre-clinical studies. Our treatment strategy requires intermittent infusions due to rapid clearance of carboplatin from the brain. In this study, carboplatin was encapsulated in lactic acid-glycolic acid copolymer (PLGA) to develop a novel drug delivery system. Neuronal and tumour cytotoxicity were assessed in primary neuronal and glioblastoma cell cultures. Distribution, tissue clearance and toxicity of carboplatin nanoparticles following CED was assessed in rat and porcine models. Carboplatin nanoparticles conferred greater tumour cytotoxicity, reduced neuronal toxicity and prolonged tissue half-life. In conclusion, this drug delivery system has the potential to improve the prognosis for patients with glioblastomas.

Convection-Enhanced Delivery of Carboplatin PLGA Nanoparticles for the Treatment of Glioblastoma

PubMed Central

Arshad, Azeem; Yang, Bin; Bienemann, Alison S.; Barua, Neil U.; Wyatt, Marcella J.; Woolley, Max; Johnson, Dave E.; Edler, Karen J.; Gill, Steven S.

2015-01-01

We currently use Convection-Enhanced Delivery (CED) of the platinum-based drug, carboplatin as a novel treatment strategy for high grade glioblastoma in adults and children. Although initial results show promise, carboplatin is not specifically toxic to tumour cells and has been associated with neurotoxicity at high infused concentrations in pre-clinical studies. Our treatment strategy requires intermittent infusions due to rapid clearance of carboplatin from the brain. In this study, carboplatin was encapsulated in lactic acid-glycolic acid copolymer (PLGA) to develop a novel drug delivery system. Neuronal and tumour cytotoxicity were assessed in primary neuronal and glioblastoma cell cultures. Distribution, tissue clearance and toxicity of carboplatin nanoparticles following CED was assessed in rat and porcine models. Carboplatin nanoparticles conferred greater tumour cytotoxicity, reduced neuronal toxicity and prolonged tissue half-life. In conclusion, this drug delivery system has the potential to improve the prognosis for patients with glioblastomas. PMID:26186224

Transport of silver nanoparticles in single fractured sandstone

NASA Astrophysics Data System (ADS)

Neukum, Christoph

2018-02-01

Silver nanoparticles (Ag-NP) are used in various consumer products and are one of the most prevalent metallic nanoparticle in commodities and are released into the environment. Transport behavior of Ag-NP in groundwater is one important aspect for the assessment of environmental impact and protection of drinking water resources in particular. Ag-NP transport processes in saturated single-fractured sandstones using triaxial flow cell experiments with different kind of sandstones is investigated. Ag-NP concentration and size are analyzed using flow field-flow fractionation and coupled SEM-EDX analysis. Results indicate that Ag-NP are more mobile and show generally lower attachment on rock surface compared to experiments in undisturbed sandstone matrix and partially fractured sandstones. Ag-NP transport is controlled by the characteristics of matrix porosity, time depending blocking of attachment sites and solute chemistry. Where Ag-NP attachment occur, it is heterogeneously distributed on the fracture surface.

Study of iron oxide nanoparticles in soil for remediation of arsenic

NASA Astrophysics Data System (ADS)

Shipley, Heather J.; Engates, Karen E.; Guettner, Allison M.

2011-06-01

There is a growing interest in the use of nanoparticles for environmental applications due to their unique physical and chemical properties. One possible application is the removal of contaminants from water. In this study, the use of iron oxide nanoparticles (19.3 nm magnetite and 37.0 nm hematite) were examined to remove arsenate and arsenite through column studies. The columns contained 1.5 or 15 wt% iron oxide nanoparticles and soil. Arsenic experiments were conducted with 1.5 wt% iron oxides at 1.5 and 6 mL/h with initial arsenate and arsenite concentrations of 100 μg/L. Arsenic release occurred after 400 PV, and 100% release was reached. A long-term study was conducted with 15 wt% magnetite nanoparticles in soil at 0.3 mL/h with an initial arsenate concentration of 100 μg/L. A negligible arsenate concentration occurred for 3559.6 pore volumes (PVs) (132.1 d). Eventually, the arsenate concentration reached about 20% after 9884.1 PV (207.9 d). A retardation factor of about 6742 was calculated indicating strong adsorption of arsenic to the magnetite nanoparticles in the column. Also, increased adsorption was observed after flow interruption. Other experiments showed that arsenic and 12 other metals (V, Cr, Co, Mn, Se, Mo, Cd, Pb, Sb, Tl, Th, U) could be simultaneously removed by the iron oxide nanoparticles in soil. Effluent concentrations were less than 10% for six out of the 12 metals. Desorption experiment showed partial irreversible sorption of arsenic to the iron oxide nanoparticle surface. Strong adsorption, large retardation factor, and resistant desorption suggest that magnetite and hematite nanoparticles have the potential to be used to remove arsenic in sandy soil possibly through in situ techniques.

Gold-Copper Nanoparticles: Nanostructural Evolution and Bifunctional Catalytic Sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Jun; Shan, Shiyao; Yang, Lefu

2012-12-12

Understanding of the atomic-scale structure is essential for exploiting the unique catalytic properties of any nanoalloy catalyst. This report describes novel findings of an investigation of the nanoscale alloying of gold-copper (AuCu) nanoparticles and its impact on the surface catalytic functions. Two pathways have been explored for the formation of AuCu nanoparticles of different compositons, including wet chemical synthesis from mixed Au- and Cu-precursor molecules, and nanoscale alloying via an evolution of mixed Au- and Cu-precursor nanoparticles near the nanoscale melting temperatures. For the evolution of mixed precursor nanoparticles, synchrotron x-ray based in-situ real time XRD was used to monitormore » the structural changes, revealing nanoscale alloying and reshaping towards an fcc-type nanoalloy (particle or cube) via a partial melting–resolidification mechanism. The nanoalloys supported on carbon or silica were characterized by in-situ high-energy XRD/PDFs, revealing an intriguing lattice "expanding-shrinking" phenomenon depending on whether the catalyst is thermochemically processed under oxidative or reductive atmosphere. This type of controllable structural changes is found to play an important role in determining the catalytic activity of the catalysts for carbon monoxide oxidation reaction. The tunable catalytic activities of the nanoalloys under thermochemically oxidative and reductive atmospheres are also discussed in terms of the bifunctional sites and the surface oxygenated metal species for carbon monoxide and oxygen activation.« less

In situ synthesis of luminescent carbon nanoparticles toward target bioimaging.

PubMed

Sharker, Shazid Md; Kim, Sung Min; Lee, Jung Eun; Jeong, Ji Hoon; In, Insik; Lee, Kang Dea; Lee, Haeshin; Park, Sung Young

2015-03-12

This paper describes the in situ synthesis of single fluorescence carbon nanoparticles (FCNs) for target bioimaging applications derived from biocompatible hyaluronic acid (HA) without using common conjugation processes. FCNs formed via the dehydration of hyaluronic acid, which were obtained by carbonizing HA, and partially carbonized HA fluorescence carbon nanoparticles (HA-FCNs), formed by a lower degree of carbonization, show good aqueous solubility, small particle size (<20 nm) and different fluorescence intensities with a red shift. After confirming the cytotoxicity of HA-FCNs and FCNs, we carried out in vitro and in vivo bioimaging studies where HA-FCNs themselves functioned as single particle triggers in target imaging. The converted nanocrystal carbon particles from HA provide outstanding features for in vitro and in vivo new targeted delivery and diagnostic tools.

National Conference[s] on Career Education: Final Report.

ERIC Educational Resources Information Center

Clark, Joseph F.; And Others

The report describes a series of conferences whose objective was to orient selected educational leaders to the implications of preparing educational personnel with a career education perspective. The first 32 pages of the report discuss project objectives and procedures, and detail participant profiles, pre- and post-conference career education…

PREFACE: Selected papers from the Fourth Topical Conference on Nanoscale Science and Engineering of the American Institute of Chemical Engineers

NASA Astrophysics Data System (ADS)

Wong, Michael S.; Lee, Gil U.

2005-07-01

This special issue of Nanotechnology contains research papers contributed by the participants of the Fourth Topical Conference on Nanoscale Science and Engineering at the Annual Meeting of the American Institute of Chemical Engineers (AIChE), which was held in Austin, Texas, USA, 7-12 November, 2004. This conference saw 284 oral presentations from institutions around the world, which is the highest number for this topical conference series to date. These presentations were organized into 64 sessions, covering the range of nanotechnology subject areas in which chemical engineers are currently engaged. These sessions included the following areas. • Fundamentals: thermodynamics at the nanoscale; applications of nanostructured fluids; transport properties in nanophase and nanoscale systems; molecular modelling methods; self and directed assembly at the nanoscale; nanofabrication and nanoscale processing; manipulation of nanophases by external fields; nanoscale systems; adsorption and transport in carbon nanotubes; nanotribology; making the transition from materials and phenomena to new technologies; operation of micro-and nano-systems. • Materials: nanoparticle synthesis and stabilization; nanoscale structure in polymers; nanotemplating of polymers; synthesis of carbon nanotubes and nanotube-based materials; nanowires; nanoparticle assemblies and superlattices; nanoelectronic materials; self-assembly of templated inorganic materials; nanostructured hybrid organic/inorganic materials; gas phase synthesis of nanoparticles; multicomponent structured particles; nano energetic materials; liquid-phase synthesis of nanoparticles. • Energy: synthesis and characterization of nanostructured catalytic materials; nanomaterials and devices for energy applications. • Biotechnology: nanobiotechnology; nanotechnology for the biotechnology and pharmaceuticals industries; nanotechnology and nanobiotechnology for sensors; advances in biomaterials, bionanotechnology, biomimetic

CONFERENCE NOTE: Conference on Precision Electromagnetic Measurements

NASA Astrophysics Data System (ADS)

1991-01-01

The next Conference on Precision Electromagnetic Measurements (CPEM), will be held from 9 to 12 June 1992 at the Centre des Nouvelles Industries et Technologies (CNIT), La Défense, Paris, France. This conference, which is held every two years and whose importance and high level, confirmed by thirty years' experience, are recognized throughout the world, can be considered as a forum in which scientists, metrologists and professionals will have the opportunity to present and compare their research results on fundamental constants, standards and new techniques of precision measurement in the electromagnetic domain. Topics The following topics are regarded as the most appropriate for this conference: realization of units and fundamental constants d.c. a.c. and high voltage time and frequency radio-frequency and microwaves dielectrics, antennas, fields lasers, fibre optics advanced instrumentation, cryoelectronics. There will also be a session on international cooperation. Conference Language The conference language will be English. No translation will be provided. Organizers Société des Electriciens et des Electroniciens (SEE). Bureau National de Métrologie (BNM) Sponsors Institute of Electrical and Electronics Engineers (IEEE) Instrumentation & Measurement Society Union Radio Scientifique Internationale United States National Institute of Standards and Technology Centre National d'Etudes des Télécommunications Mouvement Français pour la Qualité, Section Métrologie Comité National Français de Radioélectricité Scientifique Contact Jean Zara, CPEM 92 publicity, Bureau National de Métrologie, 22, rue Monge, 75005 Paris Tel.: (33) 1 46 34 48 16, Fax: (33) 1 46 34 48 63

Impact of Gender and Conference Size on Conference Preferences--Employing Natural Language Processing

ERIC Educational Resources Information Center

Eckhaus, Eyal; Davidovitch, Nitza

2018-01-01

This pilot study focuses on the impact of academic conferences from a gender-based perspective. What motivates faculty members to attend conferences? Which conferences do they choose? Can differences be found between men and women in their attitude to the effect of the conference and its contribution to their academic work, in light of many…

Ligand structure and mechanical properties of single-nanoparticle-thick membranes.

PubMed

Salerno, K Michael; Bolintineanu, Dan S; Lane, J Matthew D; Grest, Gary S

2015-06-01

The high mechanical stiffness of single-nanoparticle-thick membranes is believed to result from the local structure of ligand coatings that mediate interactions between nanoparticles. These ligand structures are not directly observable experimentally. We use molecular dynamics simulations to observe variations in ligand structure and simultaneously measure variations in membrane mechanical properties. We have shown previously that ligand end group has a large impact on ligand structure and membrane mechanical properties. Here we introduce and apply quantitative molecular structure measures to these membranes and extend analysis to multiple nanoparticle core sizes and ligand lengths. Simulations of nanoparticle membranes with a nanoparticle core diameter of 4 or 6 nm, a ligand length of 11 or 17 methylenes, and either carboxyl (COOH) or methyl (CH(3)) ligand end groups are presented. In carboxyl-terminated ligand systems, structure and interactions are dominated by an end-to-end orientation of ligands. In methyl-terminated ligand systems large ordered ligand structures form, but nanoparticle interactions are dominated by disordered, partially interdigitated ligands. Core size and ligand length also affect both ligand arrangement within the membrane and the membrane's macroscopic mechanical response, but are secondary to the role of the ligand end group. Moreover, the particular end group (COOH or CH(3)) alters the nature of how ligand length, in turn, affects the membrane properties. The effect of core size does not depend on the ligand end group, with larger cores always leading to stiffer membranes. Asymmetry in the stress and ligand density is observed in membranes during preparation at a water-vapor interface, with the stress asymmetry persisting in all membranes after drying.

Ligand structure and mechanical properties of single-nanoparticle thick membranes

DOE PAGES

Salerno, Kenneth Michael; Bolintineanu, Dan S.; Lane, J. Matthew D.; ...

2015-06-16

We believe that the high mechanical stiffness of single-nanoparticle-thick membranes is the result of the local structure of ligand coatings that mediate interactions between nanoparticles. These ligand structures are not directly observable experimentally. We use molecular dynamics simulations to observe variations in ligand structure and simultaneously measure variations in membrane mechanical properties. We have shown previously that ligand end group has a large impact on ligand structure and membrane mechanical properties. Here we introduce and apply quantitative molecular structure measures to these membranes and extend analysis to multiple nanoparticle core sizes and ligand lengths. Simulations of nanoparticle membranes with amore » nanoparticle core diameter of 4 or 6 nm, a ligand length of 11 or 17 methylenes, and either carboxyl (COOH) or methyl (CH 3) ligand end groups are presented. In carboxyl-terminated ligand systems, structure and interactions are dominated by an end-to-end orientation of ligands. In methyl-terminated ligand systems large ordered ligand structures form, but nanoparticle interactions are dominated by disordered, partially interdigitated ligands. Core size and ligand length also affect both ligand arrangement within the membrane and the membrane's macroscopic mechanical response, but are secondary to the role of the ligand end group. Additionally, the particular end group (COOH or CH 3) alters the nature of how ligand length, in turn, affects the membrane properties. The effect of core size does not depend on the ligand end group, with larger cores always leading to stiffer membranes. Asymmetry in the stress and ligand density is observed in membranes during preparation at a water-vapor interface, with the stress asymmetry persisting in all membranes after drying.« less

A low cost mobile phone dark-field microscope for nanoparticle-based quantitative studies.

PubMed

Sun, Dali; Hu, Tony Y

2018-01-15

Dark-field microscope (DFM) analysis of nanoparticle binding signal is highly useful for a variety of research and biomedical applications, but current applications for nanoparticle quantification rely on expensive DFM systems. The cost, size, limited robustness of these DFMs limits their utility for non-laboratory settings. Most nanoparticle analyses use high-magnification DFM images, which are labor intensive to acquire and subject to operator bias. Low-magnification DFM image capture is faster, but is subject to background from surface artifacts and debris, although image processing can partially compensate for background signal. We thus mated an LED light source, a dark-field condenser and a 20× objective lens with a mobile phone camera to create an inexpensive, portable and robust DFM system suitable for use in non-laboratory conditions. This proof-of-concept mobile DFM device weighs less than 400g and costs less than $2000, but analysis of images captured with this device reveal similar nanoparticle quantitation results to those acquired with a much larger and more expensive desktop DFMM system. Our results suggest that similar devices may be useful for quantification of stable, nanoparticle-based activity and quantitation assays in resource-limited areas where conventional assay approaches are not practical. Copyright © 2017 Elsevier B.V. All rights reserved.

Crisis or Conference! Master List for Conference Planners.

ERIC Educational Resources Information Center

Carey, Tony

This conference organizer's guide contains 42 lists of ideas, reminders, things to check, and questions to ask when a person is planning an event such as a conference, workshop, or training session. Written from a British point of view, the guide is organized into four parts in chronological order: preplanning, planning, onsite, and…

Unsteady mixed convection flow of Casson fluid past an inclined stretching sheet in the presence of nanoparticles

NASA Astrophysics Data System (ADS)

Rawi, N. A.; Ilias, M. R.; Lim, Y. J.; Isa, Z. M.; Shafie, S.

2017-09-01

The influence of nanoparticles on the unsteady mixed convection flow of Casson fluid past an inclined stretching sheet is investigated in this paper. The effect of gravity modulation on the flow is also considered. Carboxymethyl cellulose solution (CMC) is chosen as the base fluid and copper as nanoparticles. The basic governing nonlinear partial differential equations are transformed using appropriate similarity transformation and solved numerically using an implicit finite difference scheme by means of the Keller-box method. The effect of nanoparticles volume fraction together with the effect of inclination angle and Casson parameter on the enhancement of heat transfer of Casson nanofluid is discussed in details. The velocity and temperature profiles as well as the skin friction coefficient and the Nusselt number are presented and analyzed.

Ni doped Fe3O4 magnetic nanoparticles.

PubMed

Larumbe, S; Gómez-Polo, C; Pérez-Landazábal, J I; García-Prieto, A; Alonso, J; Fdez-Gubieda, M L; Cordero, D; Gómez, J

2012-03-01

In this work, the effect of nickel doping on the structural and magnetic properties of Fe3O4 nanoparticles is analysed. Ni(x)Fe(3-x)O4 nanoparticles (x = 0, 0.04, 0.06 and 0.11) were obtained by chemical co-precipitation method, starting from a mixture of FeCl2 x 4H2O and Ni(AcO)2 x 4H2O salts. The analysis of the structure and composition of the synthesized nanoparticles confirms their nanometer size (main sizes around 10 nm) and the inclusion of the Ni atoms in the characteristic spinel structure of the magnetite Fe3O4 phase. In order to characterize in detail the structure of the samples, X-ray absorption (XANES) measurements were performed on the Ni and Fe K-edges. The results indicate the oxidation of the Ni atoms to the 2+ state and the location of the Ni2+ cations in the Fe2+ octahedral sites. With respect to the magnetic properties, the samples display the characteristic superparamagnetic behaviour, with anhysteretic magnetic response at room temperature. The estimated magnetic moment confirms the partial substitution of the Fe2+ cations by Ni2+ atoms in the octahedral sites of the spinel structure.

A facile single-step synthesis of ternary multicore magneto-plasmonic nanoparticles.

PubMed

Benelmekki, Maria; Bohra, Murtaza; Kim, Jeong-Hwan; Diaz, Rosa E; Vernieres, Jerome; Grammatikopoulos, Panagiotis; Sowwan, Mukhles

2014-04-07

We report a facile single-step synthesis of ternary hybrid nanoparticles (NPs) composed of multiple dumbbell-like iron-silver (FeAg) cores encapsulated by a silicon (Si) shell using a versatile co-sputter gas-condensation technique. In comparison to previously reported binary magneto-plasmonic NPs, the advantage conferred by a Si shell is to bind the multiple magneto-plasmonic (FeAg) cores together and prevent them from aggregation at the same time. Further, we demonstrate that the size of the NPs and number of cores in each NP can be modulated over a wide range by tuning the experimental parameters.

ICCK Conference Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, William H.

2013-05-28

The 7th International Conference on Chemical Kinetics (ICCK) was held July 10-14, 2011, at Massachusetts Institute of Technology (MIT), in Cambridge, MA, hosted by Prof. William H. Green of MIT's Chemical Engineering department. This cross-disciplinary meeting highlighted the importance of fundamental understanding of elementary reactions to the full range of chemical investigations. The specific conference focus was on elementary-step kinetics in both the gas phase and in condensed phase. The meeting provided a unique opportunity to discuss how the same reactive species and reaction motifs manifest under very different reaction conditions (e.g. atmospheric, aqueous, combustion, plasma, in nonaqueous solvents, onmore » surfaces.). The conference featured special sessions on new/improved experimental techniques, improved models and data analysis for interpreting complicated kinetics, computational kinetics (especially rate estimates for large kinetic models), and a panel discussion on how the community should document/archive kinetic data. In the past, this conference had been limited to homogeneous gas-phase and liquid-phase systems. This conference included studies of heterogeneous kinetics which provide rate constants for, or insight into, elementary reaction steps. This Grant from DOE BES covered about half of the subsidies we provided to students and postdocs who attended the conference, by charging them reduced-rate registration fees. The complete list of subsidies provided are listed in Table 1 below. This DOE funding was essential to making the conference affordable to graduate students, and indeed the attendance at this conference was higher than at previous conferences in this series. Donations made by companies provided additional subsidies, leveraging the DOE funding. The conference was very effective in educating graduate students and important in fostering scientific interactions, particularly between scientists studying gas phase and liquid phase

Pair interactions in polyelectrolyte-nanoparticle systems: Influence of dielectric inhomogeneities and the partial dissociation of polymers and nanoparticles.

PubMed

Pryamitsyn, Victor; Ganesan, Venkat

2015-10-28

We study the effective pair interactions between two charged spherical particles in polyelectrolyte solutions using polymer self-consistent field theory. In a recent study [V. Pryamitsyn and V. Ganesan, Macromolecules 47, 6095 (2015)], we considered a model in which the particles possess fixed charge density, the polymers contain a prespecified amount of dissociated charges and, the dielectric constant of the solution was assumed to be homogeneous in space and independent of the polymer concentration. In this article, we present results extending our earlier model to study situations in which either or both the particle and the polymers possess partially dissociable groups. Additionally, we also consider the case when the dielectric constant of the solution depends on the local concentration of the polymers and when the particle's dielectric constant is lower than that of the solvent. For each case, we quantify the polymer-mediated interactions between the particles as a function of the polymer concentrations and the degree of dissociation of the polymer and particles. Consistent with the results of our previous study, we observe that the polymer-mediated interparticle interactions consist of a short-range attraction and a long-range repulsion. The partial dissociablity of the polymer and particles was seen to have a strong influence on the strength of the repulsive portion of the interactions. Rendering the dielectric permittivity to be inhomogeneous has an even stronger effect on the repulsive interactions and results in changes to the qualitative nature of interactions in some parametric ranges.

Hypoxia Responsive, Tumor Penetrating Lipid Nanoparticles for Delivery of Chemotherapeutics to Pancreatic Cancer Cell Spheroids.

PubMed

Kulkarni, Prajakta; Haldar, Manas K; Katti, Preeya; Dawes, Courtney; You, Seungyong; Choi, Yongki; Mallik, Sanku

2016-08-17

Solid tumors are often poorly irrigated due to structurally compromised microcirculation. Uncontrolled multiplication of cancer cells, insufficient blood flow, and the lack of enough oxygen and nutrients lead to the development of hypoxic regions in the tumor tissues. As the partial pressure of oxygen drops below the necessary level (10 psi), the cancer cells modulate their genetic makeup to survive. Hypoxia triggers tumor progression by enhancing angiogenesis, cancer stem cell production, remodeling of the extracellular matrix, and epigenetic changes in the cancer cells. However, the hypoxic regions are usually located deep in the tumors and are usually inaccessible to the intravenously injected drug carrier or the drug. Considering the designs of the reported nanoparticles, it is likely that the drug is delivered to the peripheral tumor tissues, close to the blood vessels. In this study, we prepared lipid nanoparticles (LNs) comprising the synthesized hypoxia-responsive lipid and a peptide-lipid conjugate. We observed that the resultant LNs penetrated to the hypoxic regions of the tumors. Under low oxygen partial pressure, the hypoxia-responsive lipid undergoes reduction, destabilizing the lipid membrane, and releasing encapsulated drugs from the nanoparticles. We demonstrated the results employing spheroidal cultures of the pancreatic cancer cells BxPC-3. We observed that the peptide-decorated, drug encapsulated LNs reduced the viability of pancreatic cancer cells of the spheroids to 35% under hypoxic conditions.

Gold nanoparticles as physiological markers of urine internalization into urothelial cells in vivo

PubMed Central

Hudoklin, Samo; Zupančič, Daša; Makovec, Darko; Kreft, Mateja Erdani; Romih, Rok

2013-01-01

Background Urothelial bladder is the reservoir of urine and the urothelium minimizes the exchange of urine constituents with this tissue. Our aim was to test 1.9 nm biocompatible gold nanoparticles as a novel marker of internalization into the urothelial cells under physiological conditions in vivo. Methods We compared normal and neoplastic mice urothelium. Neoplastic lesions were induced by 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in drinking water for 10 weeks. Nanoparticles, intravenously injected into normal and BBN-treated mice, were filtered through the kidneys and became constituents of the urine within 90 minutes after injection. Results Gold nanoparticles were densely accumulated in the urine, while their internalization into urothelial cells depended on the cell differentiation stage. In the terminally differentiated superficial urothelial cells of normal animals, nanoparticles were occasionally found in the endosomes, but not in the fusiform vesicles. Regions of exfoliated cells were occasionally found in the normal urothelium. Superficial urothelial cells located next to exfoliated regions contained gold nanoparticles in the endosomes and in the cytosol beneath the apical plasma membrane. The urothelium of BBN-treated animals developed fat hyperplasia with moderate dysplasia. The superficial cells of BBN-treated animals were partially differentiated as demonstrated by the lack of fusiform vesicles. These cells contained the gold nanoparticles distributed in the endosomes and throughout their cytosol. Conclusion Gold nanoparticles are a valuable marker to study urine internalization into urothelial cells in vivo. Moreover, they can be used as a sensitive marker of differentiation and functionality of urothelial cells. PMID:24143099

CONFERENCE LEADERSHIP.

ERIC Educational Resources Information Center

Louisiana State Vocational Curriculum Development and Research Center, Natchitoches.

THIS INSTRUCTIONAL MATERIAL IS FOR USE BY PERSONS WHO CONDUCT CONFERENCE LEADER TRAINING PROGRAMS. SPECIFICALLY, ITS PURPOSE IS TO TRAIN VOCATIONAL TRADE AND INDUSTRIAL EDUCATION PEOPLE TO CONDUCT TRAINING CONFERENCES FOR INDUSTRY. IT IS INTENDED FOR USE IN AREA VOCATIONAL SCHOOLS IN THE PROMOTION AND DEVELOPMENT OF SUPERVISORY PERSONNEL…

76 FR 78641 - Southwestern Gas Storage Technical Conference; Notice of Public Conference

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-19

... Storage Technical Conference; Notice of Public Conference Take notice that on February 16, 2012 at 9 a.m... technical conference with interested parties to discuss issues related to natural gas storage development in... Cold Weather Event of February 1-5, 2011: Causes and Recommendations, ``[a]dditional gas storage...

Architecture of conference control functions

NASA Astrophysics Data System (ADS)

Kausar, Nadia; Crowcroft, Jon

1999-11-01

Conference control is an integral part in many-to-many communications that is used to manage and co-ordinate multiple users in conferences. There are different types of conferences which require different types of control. Some of the features of conference control may be user invoked while others are for internal management of a conference. In recent years, ITU (International Telecommunication Union) and IETF (Internet Engineering Task Force) have standardized two main models of conferencing, each system providing a set of conference control functionalities that are not easily provided in the other one. This paper analyzes the main activities appropriate for different types of conferences and presents an architecture for conference control called GCCP (Generic Conference Control Protocol). GCCP interworks different types of conferencing and provides a set of conference control functions that can be invoked by users directly. As an example of interworking, interoperation of IETF's SIP and ITU's H.323 call control functions have been examined here. This paper shows that a careful analysis of a conferencing architecture can provide a set of control functions essential for any group communication model that can be extensible if needed.

Partial migration: growth varies between resident and migratory fish.

PubMed

Gillanders, Bronwyn M; Izzo, Christopher; Doubleday, Zoë A; Ye, Qifeng

2015-03-01

Partial migration occurs in many taxa and ecosystems and may confer survival benefits. Here, we use otolith chemistry data to determine whether fish from a large estuarine system were resident or migratory, and then examine whether contingents display differences in modelled growth based on changes in width of otolith growth increments. Sixty-three per cent of fish were resident based on Ba : Ca of otoliths, with the remainder categorized as migratory, with both contingents distributed across most age/size classes and both sexes, suggesting population-level bet hedging. Migrant fish were in slightly better condition than resident fish based on Fulton's K condition index. Migration type (resident versus migratory) was 56 times more likely to explain variation in growth than a model just incorporating year- and age-related growth trends. While average growth only varied slightly between resident and migratory fish, year-to-year variation was significant. Such dynamism in growth rates likely drives persistence of both life-history types. The complex relationships in growth between contingents suggest that management of species exhibiting partial migration is challenging, especially in a world subject to a changing climate. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Poly(organo phosphazene) nanoparticles surface modified with poly(ethylene oxide).

PubMed

Vandorpe, J; Schacht, E; Stolnik, S; Garnett, M C; Davies, M C; Illum, L; Davis, S S

1996-10-05

The use of biodegradable derivatives of poly(organo phosphazenes) for the preparation of nanoparticles and their surface modification with the novel poly(ethylene oxide) derivative of poly(organo phosphazene) has been assessed using a range of in vitro characterization methods. The nanoparticles were produced by the precipitation solvent evaporation method from the derivative co-substituted with phenylalanine and glycine ethyl ester side groups. A reduction in particle size to less than 200 nm was achieved by an increase in pH of the preparation medium. The formation (and colloidal stability) of these nanoparticles seems to be controlled by two opposite effects: attractive hydrophobic interactions between phenylalanine ester groups and electrostatic repulsions arising from the carboxyl groups formed due to (partial) hydrolysis of the ester bond(s) at the high pH of the preparation medium. The poly[(glycine ethyl ester)phosphazene] derivative containing 5000-Da poly(ethylene oxide) as 5% of the side groups was used for the surface modification of nanoparticles. Adsorbed onto the particles, the polymer produced a thick coating layer of approximately 35 nm. The coated nanoparticles exhibited reduced surface negative potential and improved colloidal stability toward electrolyte-induced flocculation, relative to the uncoated system. However, the steric stabilization provided was less effective than that of a Poloxamine 908 coating. This difference in effectiveness of the steric stabilization might indicate that, although both the stabilizing polymers possess a 5000-Da poly(ethylene oxide) moiety, there is a difference in the arrangements of these poly(ethylene oxide) chains at the particle surface. (c) 1996 John Wiley & Sons, Inc.

Fe3O4 nanoparticles and nanocomposites with potential application in biomedicine and in communication technologies: Nanoparticle aggregation, interaction, and effective magnetic anisotropy

NASA Astrophysics Data System (ADS)

Allia, P.; Barrera, G.; Tiberto, P.; Nardi, T.; Leterrier, Y.; Sangermano, M.

2014-09-01

Magnetite nanoparticles with a size of 5-6 nm with potential impact on biomedicine and information/communication technologies were synthesized by thermal decomposition of Fe(acac)3 and subsequently coated with a silica shell exploiting a water-in-oil synthetic procedure. The as-produced powders (comprised of either Fe3O4 or Fe3O4@silica nanoparticles) were mixed with a photocurable resin obtaining two magnetic nanocomposites with the same nominal amount of magnetic material. The static magnetic properties of the two nanopowders and the corresponding nanocomposites were measured in the 10 K-300 K temperature range. Magnetic measurements are shown here to be able to give unambiguous information on single-particle properties such as particle size and magnetic anisotropy as well as on nanoparticle aggregation and interparticle interaction. A comparison between the size distribution functions obtained from magnetic measurements and from TEM images shows that figures estimated from properly analyzed magnetic measurements are very close to the actual values. In addition, the present analysis allows us to determine the value of the effective magnetic anisotropy and to estimate the anisotropy contribution from the surface. The Field-cooled/zero field cooled curves reveal a high degree of particle aggregation in the Fe3O4 nanopowder, which is partially reduced by silica coating and strongly decreased by dissolution in the host polymer. In all considered materials, the nanoparticles are magnetically interacting, the interaction strength being a function of nanoparticle environment and being the lowest in the nanocomposite containing bare, well-separate Fe3O4 particles. All samples behave as interacting superparamagnetic materials instead of ideal superparamagnets and follow the corresponding scaling law.

Preparation and characterization of 6-mercaptopurine-coated magnetite nanoparticles as a drug delivery system

PubMed Central

Dorniani, Dena; Hussein, Mohd Zobir bin; Kura, Aminu Umar; Fakurazi, Sharida; Shaari, Abdul Halim; Ahmad, Zalinah

2013-01-01

Background Iron oxide nanoparticles are of considerable interest because of their use in magnetic recording tape, ferrofluid, magnetic resonance imaging, drug delivery, and treatment of cancer. The specific morphology of nanoparticles confers an ability to load, carry, and release different types of drugs. Methods and results We synthesized superparamagnetic nanoparticles containing pure iron oxide with a cubic inverse spinal structure. Fourier transform infrared spectra confirmed that these Fe3O4 nanoparticles could be successfully coated with active drug, and thermogravimetric and differential thermogravimetric analyses showed that the thermal stability of iron oxide nanoparticles coated with chitosan and 6-mercaptopurine (FCMP) was markedly enhanced. The synthesized Fe3O4 nanoparticles and the FCMP nanocomposite were generally spherical, with an average diameter of 9 nm and 19 nm, respectively. The release of 6-mercaptopurine from the FCMP nanocomposite was found to be sustained and governed by pseudo-second order kinetics. In order to improve drug loading and release behavior, we prepared a novel nanocomposite (FCMP-D), ie, Fe3O4 nanoparticles containing the same amounts of chitosan and 6-mercaptopurine but using a different solvent for the drug. The results for FCMP-D did not demonstrate “burst release” and the maximum percentage release of 6-mercaptopurine from the FCMP-D nanocomposite reached about 97.7% and 55.4% within approximately 2,500 and 6,300 minutes when exposed to pH 4.8 and pH 7.4 solutions, respectively. By MTT assay, the FCMP nanocomposite was shown not to be toxic to a normal mouse fibroblast cell line. Conclusion Iron oxide coated with chitosan containing 6-mercaptopurine prepared using a coprecipitation method has the potential to be used as a controlled-release formulation. These nanoparticles may serve as an alternative drug delivery system for the treatment of cancer, with the added advantage of sparing healthy surrounding cells and

Selective self-assembly of adenine-silver nanoparticles forms rings resembling the size of cells

NASA Astrophysics Data System (ADS)

Choi, Sungmoon; Park, Soonyoung; Yang, Seon-Ah; Jeong, Yujin; Yu, Junhua

2015-12-01

Self-assembly has played critical roles in the construction of functional nanomaterials. However, the structure of the macroscale multicomponent materials built by the self-assembly of nanoscale building blocks is hard to predict due to multiple intermolecular interactions of great complexity. Evaporation of solvents is usually an important approach to induce kinetically stable assemblies of building blocks with a large-scale specific arrangement. During such a deweting process, we tried to monitor the possible interactions between silver nanoparticles and nucleobases at a larger scale by epifluorescence microscopy, thanks to the doping of silver nanoparticles with luminescent silver nanodots. ssDNA oligomer-stabilized silver nanoparticles and adenine self-assemble to form ring-like compartments similar to the size of modern cells. However, the silver ions only dismantle the self-assembly of adenine. The rings are thermodynamically stable as the drying process only enrich the nanoparticles-nucleobase mixture to a concentration that activates the self-assembly. The permeable membrane-like edge of the ring is composed of adenine filaments glued together by silver nanoparticles. Interestingly, chemicals are partially confined and accumulated inside the ring, suggesting that this might be used as a microreactor to speed up chemical reactions during a dewetting process.

Selective self-assembly of adenine-silver nanoparticles forms rings resembling the size of cells

PubMed Central

Choi, Sungmoon; Park, Soonyoung; Yang, Seon-Ah; Jeong, Yujin; Yu, Junhua

2015-01-01

Self-assembly has played critical roles in the construction of functional nanomaterials. However, the structure of the macroscale multicomponent materials built by the self-assembly of nanoscale building blocks is hard to predict due to multiple intermolecular interactions of great complexity. Evaporation of solvents is usually an important approach to induce kinetically stable assemblies of building blocks with a large-scale specific arrangement. During such a deweting process, we tried to monitor the possible interactions between silver nanoparticles and nucleobases at a larger scale by epifluorescence microscopy, thanks to the doping of silver nanoparticles with luminescent silver nanodots. ssDNA oligomer-stabilized silver nanoparticles and adenine self-assemble to form ring-like compartments similar to the size of modern cells. However, the silver ions only dismantle the self-assembly of adenine. The rings are thermodynamically stable as the drying process only enrich the nanoparticles-nucleobase mixture to a concentration that activates the self-assembly. The permeable membrane-like edge of the ring is composed of adenine filaments glued together by silver nanoparticles. Interestingly, chemicals are partially confined and accumulated inside the ring, suggesting that this might be used as a microreactor to speed up chemical reactions during a dewetting process. PMID:26643504

Probing Novel Roles of the Mitochondrial Uniporter in Ovarian Cancer Cells Using Nanoparticles*♦

PubMed Central

Arvizo, Rochelle R.; Moyano, Daniel F.; Saha, Sounik; Thompson, Michael A.; Bhattacharya, Resham; Rotello, Vincent M.; Prakash, Y. S.; Mukherjee, Priyabrata

2013-01-01

Nanoparticles provide a potent tool for targeting and understanding disease mechanisms. In this regard, cancer cells are surprisingly resistant to the expected toxic effects of positively charged gold nanoparticles (+AuNPs). Our investigations led to the identification of MICU1, regulator of mitochondrial calcium uniporter, as a key molecule conferring cancer cells with resistance to +AuNPs. The increase in cytosolic [Ca2+]cyto in malignant cells induced by +AuNPs is counteracted by MICU1, preventing cell death. Pharmacological or siRNA-mediated inhibition of mitochondrial Ca+2 entry leads to endoplasmic reticulum stress and sensitizes cancer cells to +AuNP-induced cytotoxicity. Silencing MICU1 decreases Bcl-2 expression and increases caspase-3 activity and cytosolic cytochrome c levels, thus initiating the mitochondrial pathway for apoptosis: effects further enhanced by +AuNPs. This study highlights the potential of nanomaterials as a tool to broaden our understanding of cellular processes, establishes MICU1 as a novel regulator of the machinery in cancer cells that prevents apoptosis, and emphasizes the need to synergize nanoparticle design with understanding of mitochondrial machinery for enhancing targeted cellular toxicity. PMID:23615904

4th integrated transportation management systems (ITMS) conference : conference proceedings

DOT National Transportation Integrated Search

2001-08-01

This report documents the proceedings from the 4th Integrated Transportation Management Systems (ITMS) Conference, ITMS: A Key Strategy to Optimize Surface Transportation System Performance, held in Newark, New Jersey on July 15-18, 2001. The Confere...

Development of polymeric-cationic peptide composite nanoparticles, a nanoparticle-in-nanoparticle system for controlled gene delivery.

PubMed

Jain, Arvind K; Massey, Ashley; Yusuf, Helmy; McDonald, Denise M; McCarthy, Helen O; Kett, Vicky L

2015-01-01

We report the formulation of novel composite nanoparticles that combine the high transfection efficiency of cationic peptide-DNA nanoparticles with the biocompatibility and prolonged delivery of polylactic acid-polyethylene glycol (PLA-PEG). The cationic cell-penetrating peptide RALA was used to condense DNA into nanoparticles that were encapsulated within a range of PLA-PEG copolymers. The composite nanoparticles produced exhibited excellent physicochemical properties including size <200 nm and encapsulation efficiency >80%. Images of the composite nanoparticles obtained with a new transmission electron microscopy staining method revealed the peptide-DNA nanoparticles within the PLA-PEG matrix. Varying the copolymers modulated the DNA release rate >6 weeks in vitro. The best formulation was selected and was able to transfect cells while maintaining viability. The effect of transferrin-appended composite nanoparticles was also studied. Thus, we have demonstrated the manufacture of composite nanoparticles for the controlled delivery of DNA.

Development of polymeric–cationic peptide composite nanoparticles, a nanoparticle-in-nanoparticle system for controlled gene delivery

PubMed Central

Jain, Arvind K; Massey, Ashley; Yusuf, Helmy; McDonald, Denise M; McCarthy, Helen O; Kett, Vicky L

2015-01-01

We report the formulation of novel composite nanoparticles that combine the high transfection efficiency of cationic peptide-DNA nanoparticles with the biocompatibility and prolonged delivery of polylactic acid–polyethylene glycol (PLA-PEG). The cationic cell-penetrating peptide RALA was used to condense DNA into nanoparticles that were encapsulated within a range of PLA-PEG copolymers. The composite nanoparticles produced exhibited excellent physicochemical properties including size <200 nm and encapsulation efficiency >80%. Images of the composite nanoparticles obtained with a new transmission electron microscopy staining method revealed the peptide-DNA nanoparticles within the PLA-PEG matrix. Varying the copolymers modulated the DNA release rate >6 weeks in vitro. The best formulation was selected and was able to transfect cells while maintaining viability. The effect of transferrin-appended composite nanoparticles was also studied. Thus, we have demonstrated the manufacture of composite nanoparticles for the controlled delivery of DNA. PMID:26648722

Cytotoxicity and intracellular fate of PLGA and chitosan-coated PLGA nanoparticles in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells.

PubMed

Trif, Mihaela; Florian, Paula E; Roseanu, Anca; Moisei, Magdalena; Craciunescu, Oana; Astete, Carlos E; Sabliov, Cristina M

2015-11-01

Polymeric nanoparticles (NPs) are known to facilitate intracellular uptake of drugs to improve their efficacy, with minimum bioreactivity. The goal of this study was to assess cellular uptake and trafficking of PLGA NPs and chitosan (Chi)-covered PLGA NPs in Madin-Darby bovine kidney (MDBK) and human colorectal adenocarcinoma (Colo 205) cells. Both PLGA and Chi-PLGA NPs were not cytotoxic to the studied cells at concentrations up to 2500 μg/mL. The positive charge conferred by the chitosan deposition on the PLGA NPs improved NPs uptake by MDBK cells. In this cell line, Chi-PLGA NPs colocalized partially with early endosomes compartment and showed a more consistent perinuclear localization than PLGA NPs. Kinetic uptake of PLGA NPs by Colo 205 was slower than that by MDBK cells, detected only at 24 h, exceeding that of Chi-PLGA NPs. This study offers new insights on NP interaction with target cells supporting the use of NPs as novel nutraceuticals/drug delivery systems in metabolic disorders or cancer therapy. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3599-3611, 2015. © 2015 Wiley Periodicals, Inc.

RFLP Mapping of Genes Conferring Complete and Partial Resistance to Blast in a Durably Resistant Rice Cultivar

PubMed Central

Wang, G. L.; Mackill, D. J.; Bonman, J. M.; McCouch, S. R.; Champoux, M. C.; Nelson, R. J.

1994-01-01

Moroberekan, a japonica rice cultivar with durable resistance to blast disease in Asia, was crossed to the highly susceptible indica cultivar, CO39, and 281 F(7) recombinant inbred (RI) lines were produced by single seed descent. The population was evaluated for blast resistance in the greenhouse and the field, and was analyzed with 127 restriction fragment length polymorphism (RFLP) markers. Two dominant loci associated with qualitative resistance to five isolates of the fungus were tentatively named Pi-5(t) and Pi-7(t). They were mapped on chromosomes 4 and 11, respectively. To identify quantitative trait loci (QTLs) affecting partial resistance, RI lines were inoculated with isolate PO6-6 of Pyricularia oryzae in polycyclic tests. Ten chromosomal segments were found to be associated with effects on lesion number (P < 0.0001 and LOD > 6.0). Three of the markers associated with QTLs for partial resistance had been reported to be linked to complete blast resistance in previous studies. QTLs identified in greenhouse tests were good predictors of blast resistance at two field sites. This study illustrates the usefulness of RI lines for mapping a complex trait such as blast resistance and suggests that durable resistance in the traditional variety, Moroberekan, involves a complex of genes associated with both partial and complete resistance. PMID:7912216

Programmed Nanoparticle-Loaded Nanoparticles for Deep-Penetrating 3D Cancer Therapy.

PubMed

Kim, Jinhwan; Jo, Changshin; Lim, Won-Gwang; Jung, Sungjin; Lee, Yeong Mi; Lim, Jun; Lee, Haeshin; Lee, Jinwoo; Kim, Won Jong

2018-05-18

Tumors are 3D, composed of cellular agglomerations and blood vessels. Therapies involving nanoparticles utilize specific accumulations due to the leaky vascular structures. However, systemically injected nanoparticles are mostly uptaken by cells located on the surfaces of cancer tissues, lacking deep penetration into the core cancer regions. Herein, an unprecedented strategy, described as injecting "nanoparticle-loaded nanoparticles" to address the long-lasting problem is reported for effective surface-to-core drug delivery in entire 3D tumors. The "nanoparticle-loaded nanoparticle" is a silica nanoparticle (≈150 nm) with well-developed, interconnected channels (diameter of ≈30 nm), in which small gold nanoparticles (AuNPs) (≈15 nm) with programmable DNA are located. The nanoparticle (AuNPs)-loaded nanoparticles (silica): (1) can accumulate in tumors through leaky vascular structures by protecting the inner therapeutic AuNPs during blood circulation, and then (2) allow diffusion of the AuNPs for penetration into the entire surface-to-core tumor tissues, and finally (3) release a drug triggered by cancer-characteristic pH gradients. The hierarchical "nanoparticle-loaded nanoparticle" can be a rational design for cancer therapies because the outer large nanoparticles are effective in blood circulation and in protection of the therapeutic nanoparticles inside, allowing the loaded small nanoparticles to penetrate deeply into 3D tumors with anticancer drugs. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Understanding nanoparticle-mediated nucleation pathways of anisotropic nanoparticles

NASA Astrophysics Data System (ADS)

Laramy, Christine R.; Fong, Lam-Kiu; Jones, Matthew R.; O'Brien, Matthew N.; Schatz, George C.; Mirkin, Chad A.

2017-09-01

Several seed-mediated syntheses of low symmetry anisotropic nanoparticles yield broad product distributions with multiple defect structures. This observation challenges the role of the nanoparticle precursor as a seed for certain syntheses and suggests the possibility of alternate nucleation pathways. Herein, we report a method to probe the role of the nanoparticle precursor in anisotropic nanoparticle nucleation with compositional and structural 'labels' to track their fate. We use the synthesis of gold triangular nanoprisms (Au TPs) as a model system. We propose a mechanism in which, rather than acting as a template, the nanoparticle precursor catalyzes homogenous nucleation of Au TPs.

The 2009 National Environmental Public Health Conference: one model for planning green and healthy conferences.

PubMed

Ruckart, Perri Zeitz; Moore, Cory; Burgin, Deborah; Byrne, Maggie Kelly

2011-01-01

The Centers for Disease Control and Prevention's National Center for Environmental Health and the Agency for Toxic Substances and Disease Registry committed to making their 2009 National Environmental Public Health Conference a model for green and healthy conferences. The conference included increased opportunities for physical activity, both as part of conference events and for transportation to the conference. In addition, conference meals were healthy and sustainably sourced. The conference also implemented intuitive, accessible recycling; online scheduling and evaluation to minimize hard-copy materials; and the purchase of carbon offsets to reduce the unwanted environmental impact of the conference. Public health professionals have an opportunity and obligation to support healthy behaviors at their events and to serve as leaders in this area. Facilitating healthy and sustainable choices is in alignment with goals for both public health and broader social issues-such as environmental quality-that have a direct bearing on public health.

Robot-assisted partial nephrectomy: Superiority over laparoscopic partial nephrectomy.

PubMed

Shiroki, Ryoichi; Fukami, Naohiko; Fukaya, Kosuke; Kusaka, Mamoru; Natsume, Takahiro; Ichihara, Takashi; Toyama, Hiroshi

2016-02-01

Nephron-sparing surgery has been proven to positively impact the postoperative quality of life for the treatment of small renal tumors, possibly leading to functional improvements. Laparoscopic partial nephrectomy is still one of the most demanding procedures in urological surgery. Laparoscopic partial nephrectomy sometimes results in extended warm ischemic time and severe complications, such as open conversion, postoperative hemorrhage and urine leakage. Robot-assisted partial nephrectomy exploits the advantages offered by the da Vinci Surgical System to laparoscopic partial nephrectomy, equipped with 3-D vision and a better degree in the freedom of surgical instruments. The introduction of the da Vinci Surgical System made nephron-sparing surgery, specifically robot-assisted partial nephrectomy, safe with promising results, leading to the shortening of warm ischemic time and a reduction in perioperative complications. Even for complex and challenging tumors, robotic assistance is expected to provide the benefit of minimally-invasive surgery with safe and satisfactory renal function. Warm ischemic time is the modifiable factor during robot-assisted partial nephrectomy to affect postoperative kidney function. We analyzed the predictive factors for extended warm ischemic time from our robot-assisted partial nephrectomy series. The surface area of the tumor attached to the kidney parenchyma was shown to significantly affect the extended warm ischemic time during robot-assisted partial nephrectomy. In cases with tumor-attached surface area more than 15 cm(2) , we should consider switching robot-assisted partial nephrectomy to open partial nephrectomy under cold ischemia if it is imperative. In Japan, a nationwide prospective study has been carried out to show the superiority of robot-assisted partial nephrectomy to laparoscopic partial nephrectomy in improving warm ischemic time and complications. By facilitating robotic technology, robot-assisted partial nephrectomy

Conference Resolution

NASA Astrophysics Data System (ADS)

2009-04-01

Since the first IUPAP International Conference on Women in Physics (Paris, March 2002) and the Second Conference (Rio de Janeiro, May 2005), progress has continued in most countries and world regions to attract girls to physics and advance women into leadership roles, and many working groups have formed. The Third Conference (Seoul, October 2008), with 283 attendees from 57 countries, was dedicated to celebrating the physics achievements of women throughout the world, networking toward new international collaborations, building each participant's capacity for career success, and aiding the formation of active regional working groups to advance women in physics. Despite the progress, women remain a small minority of the physics community in most countries.

Cellular transfer of magnetic nanoparticles via cell microvesicles: impact on cell tracking by magnetic resonance imaging.

PubMed

Silva, Amanda K Andriola; Wilhelm, Claire; Kolosnjaj-Tabi, Jelena; Luciani, Nathalie; Gazeau, Florence

2012-05-01

Cell labeling with magnetic nanoparticles can be used to monitor the fate of transplanted cells in vivo by magnetic resonance imaging. However, nanoparticles initially internalized in administered cells might end up in other cells of the host organism. We investigated a mechanism of intercellular cross-transfer of magnetic nanoparticles to different types of recipient cells via cell microvesicles released under cellular stress. Three cell types (mesenchymal stem cells, endothelial cells and macrophages) were labeled with 8-nm iron oxide nanoparticles. Then cells underwent starvation stress, during which they produced microvesicles that were subsequently transferred to unlabeled recipient cells. The analysis of the magnetophoretic mobility of donor cells indicated that magnetic load was partially lost under cell stress. Microvesicles shed by stressed cells participated in the release of magnetic label. Moreover, such microvesicles were uptaken by naïve cells, resulting in cellular redistribution of nanoparticles. Iron load of recipient cells allowed their detection by MRI. Cell microvesicles released under stress may be disseminated throughout the organism, where they can be uptaken by host cells. The transferred cargo may be sufficient to allow MRI detection of these secondarily labeled cells, leading to misinterpretations of the effectiveness of transplanted cells.

Eighteen Years of the Great Lakes Regional Counseling Psychology Conference: Revisiting the Need for Regional Conferences

ERIC Educational Resources Information Center

Delgado-Romero, Edward A.; Bowman, Sharon L.; Gerstein, Lawrence H.

2006-01-01

The Great Lakes Regional Conference on Counseling Psychology is the only conference to continuously fulfill the 1987 mandate issued by Division 17 for regional counseling conferences. The rationale for regional conferences is reviewed, and the 18-year history of the Great Lakes Regional Conference is examined. The authors conclude by noting the…

Laser-induced particle size tuning and structural transformations in germanium nanoparticles prepared by stain etching and colloidal synthesis route

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karatutlu, Ali, E-mail: a.karatutlu@qmul.ac.uk, E-mail: ali.karatutlu@bou.edu.tr; Electrical and Electronics Engineering, Bursa Orhangazi University, 16310 Yıldırım/Bursa; Little, William

In this study, with the aid of Raman measurements, we have observed transformations in small (∼3 nm and ∼10 nm) free-standing Ge nanoparticles under laser light exposure. The nanoparticles were obtained by the chemical stain etching of a monocrystalline Ge wafer and of Ge powder and by colloidal synthesis route. We found that the transformation path depends on laser power and exposure time. At relatively low values of the laser power (2 mW) over a period of 100 min, the Raman signal indicates transformation of the sample from a nanocrystaline to bulk-like state, followed by partial oxidation and finally a conversion of themore » entire sample into alpha-quartz type GeO{sub 2}. However, when the laser power is set at 60 mW, we observed a heat release during an explosive crystallization of the nanocrystalline material into bulk Ge without noticeable signs of oxidation. Together with the transmission electron microscopy measurements, these results suggest that the chemical stain etching method for the preparation of porous Ge may not be a top-down process as has been widely considered, but a bottom up one. Systematic studies of the laser exposure on Ge nanoparticles prepared by colloidal synthesis results in the fact that the explosive crystallisation is common for H-terminated and partially disordered Ge nanoparticles regardless of its particle size. We suggest possible bio-medical applications for the observed phenomena.« less

Parent Conferences. Beginnings Workshop.

ERIC Educational Resources Information Center

Duffy, Roslyn; And Others

1997-01-01

Presents six workshop sessions on parent conferences: (1) "Parents' Perspectives on Conferencing" (R. Duffy); (2) "Three Way Conferences" (G. Zeller); (3) "Conferencing with Parents of Infants" (K. Albrecht); (4) "Conferencing with Parents of School-Agers" (L. G. Miller); (5) "Cross Cultural Conferences" (J. Gonzalez-Mena); and (6) "Working with…

Clad-pumped Er-nanoparticle-doped fiber laser (Conference Presentation)

NASA Astrophysics Data System (ADS)

Baker, Colin C.; Friebele, E. Joseph; Rhonehouse, Daniel L.; Marcheschi, Barbara A.; Peele, John R.; Kim, Woohong; Sanghera, Jasbinder S.; Zhang, Jun; Chen, Youming; Pattnaik, Radha K.; Dubinskii, Mark

2017-03-01

Erbium-doped fiber lasers are attractive for directed energy weapons applications because they operate in a wavelength region that is both eye-safer and a window of high atmospheric transmission. For these applications a clad-pumped design is desirable, but the Er absorption must be high because of the areal dilution of the doped core vs. the pump cladding. High Er concentrations typically lead to Er ion clustering, resulting in quenching and upconversion. Nanoparticle (NP) doping of the core overcomes these problems by physically surrounding the Er ions with a cage of Al and O in the NP, which keeps them separated to minimize excited state energy transfer. A significant issue is obtaining high Er concentrations without the NP agglomeration that degrades the optical properties of the fiber core. We have developed the process for synthesizing stable Er-NP suspension which have been used to fabricate EDFs with Er concentrations >90 dB/m at 1532 nm. Matched clad fibers have been evaluated in a core-pumped MOPA with pump and signal wavelengths of 1475 and 1560 nm, respectively, and efficiencies of 72% with respect to absorbed pump have been obtained. We have fabricated both NP- and solution-doped double clad fibers, which have been measured in a clad-pumped laser testbed using a 1532 nm pump. The 1595 nm laser efficiency of the NP-doped fiber was 47.7%, which is high enough for what is believed to be the first laser experiment with the cladding pumped, NP-doped fiber. Further improvements are likely with a shaped cladding and new low-index polymer coatings with lower absorption in the 1500 - 1600 nm range.

Threats, protests greet conference.

PubMed

Struck, D

1994-09-04

In preparation for the 1994 International Conference on Population and Development, Egypt has deployed 14,000 police to protect participants from threatened violence. The Vatican has joined forces with Muslim fundamentalists to condemn the conference as a vehicle for imposing Western ideals, particularly abortion, on Third world countries. In addition, the opposition is raising the specter of a descent of homosexuals onto Cairo and Muslim fundamentalists have threatened to murder Western representatives. A suit filed by Islamic lawyers, aimed at stopping the conference, failed. Sudan and Saudi Arabia plan to boycott the conference, and it remains uncertain whether Libya will be represented. Conference organizers have not been deterred by the threats and note that the controversy has drawn public attention to the central issues under debate.

Uniform and Janus-like nanoparticles in contact with vesicles: energy landscapes and curvature-induced forces.

PubMed

Agudo-Canalejo, Jaime; Lipowsky, Reinhard

2017-03-15

Biological membranes and lipid vesicles often display complex shapes with non-uniform membrane curvature. When adhesive nanoparticles with chemically uniform surfaces come into contact with such membranes, they exhibit four different engulfment regimes as recently shown by a systematic stability analysis. Depending on the local curvature of the membrane, the particles either remain free, become partially or completely engulfed by the membrane, or display bistability between free and completely engulfed states. Here, we go beyond stability analysis and develop an analytical theory to leading order in the ratio of particle-to-vesicle size. This theory allows us to determine the local and global energy landscapes of uniform nanoparticles that are attracted towards membranes and vesicles. While the local energy landscape depends only on the local curvature of the vesicle membrane and not on the overall membrane shape, the global energy landscape describes the variation of the equilibrium state of the particle as it probes different points along the membrane surface. In particular, we find that the binding energy of a partially engulfed particle depends on the 'unperturbed' local curvature of the membrane in the absence of the particle. This curvature dependence leads to local forces that pull the partially engulfed particles towards membrane segments with lower and higher mean curvature if the particles originate from the exterior and interior solution, respectively, corresponding to endo- and exocytosis. Thus, for partial engulfment, endocytic particles undergo biased diffusion towards the membrane segments with the lowest membrane curvature, whereas exocytic particles move towards segments with the highest curvature. The curvature-induced forces are also effective for Janus particles with one adhesive and one non-adhesive surface domain. In fact, Janus particles with a strongly adhesive surface domain are always partially engulfed which implies that they provide

Cerium oxide nanoparticles, combining antioxidant and UV shielding properties, prevent UV-induced cell damage and mutagenesis

NASA Astrophysics Data System (ADS)

Caputo, Fanny; de Nicola, Milena; Sienkiewicz, Andrzej; Giovanetti, Anna; Bejarano, Ignacio; Licoccia, Silvia; Traversa, Enrico; Ghibelli, Lina

2015-09-01

Efficient inorganic UV shields, mostly based on refracting TiO2 particles, have dramatically changed the sun exposure habits. Unfortunately, health concerns have emerged from the pro-oxidant photocatalytic effect of UV-irradiated TiO2, which mediates toxic effects on cells. Therefore, improvements in cosmetic solar shield technology are a strong priority. CeO2 nanoparticles are not only UV refractors but also potent biological antioxidants due to the surface 3+/4+ valency switch, which confers anti-inflammatory, anti-ageing and therapeutic properties. Herein, UV irradiation protocols were set up, allowing selective study of the extra-shielding effects of CeO2vs. TiO2 nanoparticles on reporter cells. TiO2 irradiated with UV (especially UVA) exerted strong photocatalytic effects, superimposing their pro-oxidant, cell-damaging and mutagenic action when induced by UV, thereby worsening the UV toxicity. On the contrary, irradiated CeO2 nanoparticles, via their Ce3+/Ce4+ redox couple, exerted impressive protection on UV-treated cells, by buffering oxidation, preserving viability and proliferation, reducing DNA damage and accelerating repair; strikingly, they almost eliminated mutagenesis, thus acting as an important tool to prevent skin cancer. Interestingly, CeO2 nanoparticles also protect cells from the damage induced by irradiated TiO2, suggesting that these two particles may also complement their effects in solar lotions. CeO2 nanoparticles, which intrinsically couple UV shielding with biological and genetic protection, appear to be ideal candidates for next-generation sun shields.

Multifunctional rare-Earth vanadate nanoparticles: luminescent labels, oxidant sensors, and MRI contrast agents.

PubMed

Abdesselem, Mouna; Schoeffel, Markus; Maurin, Isabelle; Ramodiharilafy, Rivo; Autret, Gwennhael; Clément, Olivier; Tharaux, Pierre-Louis; Boilot, Jean-Pierre; Gacoin, Thierry; Bouzigues, Cedric; Alexandrou, Antigoni

2014-11-25

Collecting information on multiple pathophysiological parameters is essential for understanding complex pathologies, especially given the large interindividual variability. We report here multifunctional nanoparticles which are luminescent probes, oxidant sensors, and contrast agents in magnetic resonance imaging (MRI). Eu(3+) ions in an yttrium vanadate matrix have been demonstrated to emit strong, nonblinking, and stable luminescence. Time- and space-resolved optical oxidant detection is feasible after reversible photoreduction of Eu(3+) to Eu(2+) and reoxidation by oxidants, such as H2O2, leading to a modulation of the luminescence emission. The incorporation of paramagnetic Gd(3+) confers in addition proton relaxation enhancing properties to the system. We synthesized and characterized nanoparticles of either 5 or 30 nm diameter with compositions of GdVO4 and Gd0.6Eu0.4VO4. These particles retain the luminescence and oxidant detection properties of YVO4:Eu. Moreover, the proton relaxivity of GdVO4 and Gd0.6Eu0.4VO4 nanoparticles of 5 nm diameter is higher than that of the commercial Gd(3+) chelate compound Dotarem at 20 MHz. Nuclear magnetic resonance dispersion spectroscopy showed a relaxivity increase above 10 MHz. Complexometric titration indicated that rare-earth leaching is negligible. The 5 nm nanoparticles injected in mice were observed with MRI to concentrate in the liver and the bladder after 30 min. Thus, these multifunctional rare-earth vanadate nanoparticles pave the way for simultaneous optical and magnetic resonance detection, in particular, for in vivo localization evolution and reactive oxygen species detection in a broad range of physiological and pathophysiological conditions.

The General Conference Mennonites.

ERIC Educational Resources Information Center

Ediger, Marlow

General Conference Mennonites and Old Order Amish are compared and contrasted in the areas of physical appearance, religious beliefs, formal education, methods of farming, and home settings. General Conference Mennonites and Amish differ in physical appearance and especially in dress. The General Conference Mennonite men and women dress the same…

Impact of thermal oxidation on chemical composition and magnetic properties of iron nanoparticles

NASA Astrophysics Data System (ADS)

Krajewski, Marcin; Brzozka, Katarzyna; Tokarczyk, Mateusz; Kowalski, Grzegorz; Lewinska, Sabina; Slawska-Waniewska, Anna; Lin, Wei Syuan; Lin, Hong Ming

2018-07-01

The main objective of this work is to study the influence of thermal oxidation on the chemical composition and magnetic properties of iron nanoparticles which were manufactured in a simple chemical reduction of Fe3+ ions coming from iron salt with sodium borohydride. The annealing processing was performed in an argon atmosphere containing the traces of oxygen to avoid spontaneous oxidation of iron at temperatures ranging from 200 °C to 800 °C. The chemical composition and magnetic properties of as-prepared and thermally-treated nanoparticles were determined by means of X-ray diffractometry, Raman spectroscopy, Mössbauer spectroscopy and vibrating sample magnetometry. Due to the magnetic interactions, the investigated iron nanoparticles tended to create the dense aggregates which were difficult to split even at low temperatures. This caused that there was no empty space between them, which led to their partial sintering at elevated temperatures. These features hindered their precise morphological observations using the electron microscopy techniques. The obtained results show that the annealing process up to 800 °C resulted in a progressive change in the chemical composition of as-prepared iron nanoparticles which was associated with their oxidation. As a consequence, their magnetic properties also depended on the annealing temperature. For instance, considering the values of saturation magnetization, its highest value was recorded for the as-prepared nanoparticles at 1 T and it equals 149 emu/g, while the saturation point for nanoparticles treated at 600 °C and higher temperatures was not reached even at the magnetic field of about 5 T. Moreover, a significant enhancement of coercivity was observed for the iron nanoparticles annealed over 600 °C.

Waterside Security 2010 (WSS 2010) Conference: Post Conference Report

DTIC Science & Technology

2011-02-01

Memorandum Report NURC-MR-2011-002 Waterside Security 2010 (WSS2010) Conference: post conference report Ronald Kessel and...in NATO, NURC conducts maritime research in support of NATO’s operational and transformation requirements. Reporting to the Supreme Allied Commander...independent business process certification. Copyright © NURC 2011. NATO member nations have unlimited rights to use, modify, reproduce, release

Single step, phase controlled, large scale synthesis of ferrimagnetic iron oxide polymorph nanoparticles by thermal plasma route and their rheological properties

NASA Astrophysics Data System (ADS)

Raut, Suyog A.; Mutadak, Pallavi R.; Kumar, Shiv; Kanhe, Nilesh S.; Huprikar, Sameer; Pol, Harshawardhan V.; Phase, Deodatta M.; Bhoraskar, Sudha V.; Mathe, Vikas L.

2018-03-01

In this paper we report single step large scale synthesis of highly crystalline iron oxide nanoparticles viz. magnetite (Fe3O4) and maghemite (γ-Fe2O3) via gas phase condensation process, where micron sized iron metal powder was used as a precursor. Selective phases of iron oxide were obtained by variation of gas flow rate of oxygen and hence partial pressure of oxygen inside the plasma reactor. Most of the particles were found to possesses average crystallite size of about 20-30 nm. The DC magnetization curves recorded indicate almost super-paramagnetic nature of the iron oxide magnetic nanoparticles. Further, iron oxide nanoparticles were analyzed using Raman spectroscopy, X-ray photoelectron spectroscopy and Mossbauer spectroscopy. In order to explore the feasibility of these nanoparticles for magnetic damper application, rheological studies have been carried out and compared with commercially available Carbonyl Iron (CI) particles. The nanoparticles obtained by thermal plasma route show improved dispersion which is useful for rheological applications.

CERN automatic audio-conference service

NASA Astrophysics Data System (ADS)

Sierra Moral, Rodrigo

2010-04-01

Scientists from all over the world need to collaborate with CERN on a daily basis. They must be able to communicate effectively on their joint projects at any time; as a result telephone conferences have become indispensable and widely used. Managed by 6 operators, CERN already has more than 20000 hours and 5700 audio-conferences per year. However, the traditional telephone based audio-conference system needed to be modernized in three ways. Firstly, to provide the participants with more autonomy in the organization of their conferences; secondly, to eliminate the constraints of manual intervention by operators; and thirdly, to integrate the audio-conferences into a collaborative working framework. The large number, and hence cost, of the conferences prohibited externalization and so the CERN telecommunications team drew up a specification to implement a new system. It was decided to use a new commercial collaborative audio-conference solution based on the SIP protocol. The system was tested as the first European pilot and several improvements (such as billing, security, redundancy...) were implemented based on CERN's recommendations. The new automatic conference system has been operational since the second half of 2006. It is very popular for the users and has doubled the number of conferences in the past two years.

76 FR 67725 - Technical Conference on Penalty Guidelines; Second Notice of Technical Conference on Penalty...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-02

... Conference on Penalty Guidelines; Second Notice of Technical Conference on Penalty Guidelines On September 21... Conference on Penalty Guidelines to be held on November 17, 2011. The conference will be held from 1 p.m. to... impact of the Penalty Guidelines, which the Commission issued on September 17, 2010,\\1\\ on compliance and...

Conference Comments by the Editors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Archer, Daniel E

2009-01-01

The Symposium on Radiation Measurements and Applications (SORMA) met for the first time on the West Coast June 2-5, 2008, in Berkeley, CA. With radiation detectors increasing in number, variety, and societal importance, we plan to alternate between SORMA East (in Ann Arbor, MI) and SORMA West so that the forum will be available every two years. The topic areas for SORMA West 2008 were much the same as those of recent Ann Arbor programs, and were meant to encompass the full breadth of ionizing radiation measurement applications and technologies, with both oral and poster presentations. The technical program ofmore » SORMA 2008 included 342 scientific presentations, 116 oral presentations plus eight invited keynote lectures in plenary sessions, as well as 218 presentations in poster sessions. The SORMA 2008 meetings were attended by 439 registered participants from 25 different countries. Topics of interest at the meeting ranged from room temperature semiconductor detectors, cryogenic detectors, photodetectors, neutron detectors, novel scintillators, nonproportionality and characterization of scintillators, simulation and analysis of radiation interactions, novel radiation sources, imaging technologies and homeland security and medical applications. This was the first conference of the SORMA series to be technically cosponsored by the Institute of Electrical and Electronic Engineers (IEEE), specifically by the Nuclear and Plasma Sciences Society (NPSS) of IEEE. The co-sponsorship has been important for visibility of SORMA and for attracting a record number of new participants. This special issue of IEEE TRANSACTIONS ON NUCLEAR SCIENCE comprises the refereed proceedings of SORMA 2008, containing 128 papers on the research presentations. The Chairs of the SORMA 2008 conference would like to acknowledge partial financial support from the NNSA, DNDO, and DTRA, and organizational support from Lawrence Berkeley National Laboratory and Lawrence Livermore National

Hiding the interior region of core-shell nanoparticles with quantum invisible cloaks

NASA Astrophysics Data System (ADS)

Lee, Jeng Yi; Lee, Ray-Kuang

2014-04-01

Based on the scattering cancellation, we provide a method not only making a nanoparticle nearly invisible, but also hiding its interior region from the outside probing matter wave. By applying the interplay among the nodal points of partial waves along with the concept of streamline in fluid dynamics for probability flux, a quantum invisible cloak to the electron transport in a host semiconductor is demonstrated by simultaneously guiding the probability flux outside a hidden region and keeping the total scattering cross section negligible. As the probability flux vanishes in the interior region, one can embed any materials inside a multiple core-shell nanoparticle without affecting physical observables from the outside. Our results reveal the possibility to design a protection shield layer for fragile interior parts from the impact of transport electrons.

Pseudolatex preparation using a novel emulsion-diffusion process involving direct displacement of partially water-miscible solvents by distillation.

PubMed

Quintanar-Guerrero, D; Allémann, E; Fessi, H; Doelker, E

1999-10-25

Pseudolatexes were obtained by a new process based on an emulsification-diffusion technique involving partially water-miscible solvents. The preparation method consisted of emulsifying an organic solution of polymer (saturated with water) in an aqueous solution of a stabilizing agent (saturated with solvent) using conventional stirrers, followed by direct solvent distillation. The technique relies on the rapid displacement of the solvent from the internal into the external phase which thereby provokes polymer aggregation. Nanoparticle formation is believed to occur because rapid solvent diffusion produces regions of local supersaturation near the interface, and nanoparticles are formed due to the ensuing interfacial phase transformations and polymer aggregation that occur in these interfacial domains. Using this method, it was possible to prepare pseudolatexes of biodegradable and non-biodegradable polymers such as poly(D,L-lactic acid) and poly(epsilon-caprolactone), Eudragit E, cellulose acetate phthalate, cellulose acetate trimellitate using ethyl acetate or 2-butanone as partially water-miscible solvents and poly(vinyl alcohol) or poloxamer 407 as stabilizing agent. A transition from nano- to microparticles was observed at high polymer concentrations. At concentrations above 30% w/v of Eudragit E in ethyl acetate or cellulose acetate phthalate in 2-butanone only microparticles were obtained. This behaviour was attributed to decreased transport of polymer molecules into the aqueous phase.

78 FR 27963 - Reliability Technical Conference; Notice of Technical Conference

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-13

... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. AD13-6-000] Reliability Technical Conference; Notice of Technical Conference Take notice that the Federal Energy Regulatory... related to the reliability of the Bulk-Power System. A more formal agenda will be issued at a later date...

Encapsulation of Au Nanoparticles on a Silicon Wafer During Thermal Oxidation

PubMed Central

2013-01-01

We report the behavior of Au nanoparticles anchored onto a Si(111) substrate and the evolution of the combined structure with annealing and oxidation. Au nanoparticles, formed by annealing a Au film, appear to “float” upon a growing layer of SiO2 during oxidation at high temperature, yet they also tend to become partially encapsulated by the growing silica layers. It is proposed that this occurs largely because of the differential growth rates of the silica layer on the silicon substrate between the particles and below the particles due to limited access of oxygen to the latter. This in turn is due to a combination of blockage of oxygen adsorption by the Au and limited oxygen diffusion under the gold. We think that such behavior is likely to be seen for other metal–semiconductor systems. PMID:24163715

Enhancing magnetic nanoparticle-based DNA transfection: Intracellular-active cassette features

NASA Astrophysics Data System (ADS)

Vernon, Matthew Martin

Efficient plasmid DNA transfection of embryonic stem cells, mesenchymal stem cells, neural cell lines and the majority of primary cell lines is a current challenge in gene therapy research. Magnetic nanoparticle-based DNA transfection is a gene vectoring technique that is promising because it is capable of outperforming most other non-viral transfection methods in terms of both transfection efficiency and cell viability. The nature of the DNA vector implemented depends on the target cell phenotype, where the particle surface chemistry and DNA binding/unbinding kinetics of the DNA carrier molecule play a critical role in the many steps required for successful gene transfection. Accordingly, Neuromag, an iron oxide/polymer nanoparticle optimized for transfection of neural phenotypes, outperforms many other nanoparticles and lipidbased DNA carriers. Up to now, improvements to nanomagnetic transfection techniques have focused mostly on particle functionalization and transfection parameter optimization (cell confluence, growth media, serum starvation, magnet oscillation parameters, etc.). None of these parameters are capable of assisting the nuclear translocation of delivered plasmid DNA once the particle-DNA complex is released from the endosome and dissociates in the cell's cytoplasm. In this study, incorporation of a DNA targeting sequence (DTS) feature in the transfecting plasmid DNA confers improved nuclear translocation, demonstrating significant improvement in nanomagnetic transfection efficiency in differentiated SH-SY5Y neuroblastoma cells. Other parameters, such as days in vitro, are also found to play a role and represent potential targets for further optimization.

Partial trisomy of chromosome 22 resulting from a supernumerary marker chromosome 22 in a child with features of cat eye syndrome.

PubMed

Bélien, Valérie; Gérard-Blanluet, Marion; Serero, Stéphane; Le Dû, Nathalie; Baumann, Clarisse; Jacquemont, Marie-Line; Dupont, Céline; Krabchi, Kada; Drunat, Séverine; Elbez, Annie; Janaud, Jean-Claude; Benzacken, Brigitte; Verloes, Alain; Tabet, Anne-Claude; Aboura, Azzedine

2008-07-15

Small supernumerary marker chromosomes are present in about 0.05% of the human population. In approximately 28% of persons with these markers (excluding the approximately 60% derived from one of the acrocentric chromosomes), an abnormal phenotype is observed. We report on a 3-month-old girl with intrauterine growth retardation, craniofacial features, hypotonia, partial coloboma of iris and total anomalous pulmonary venous return. Cytogenetic analysis showed the presence of a supernumerary marker chromosome, identified by fluorescence in situ hybridization as part of chromosome 22, and conferring a proximal partial trisomy 22q22.21, not encompassing the DiGeorge critical region (RP11-154H4 + , TBX1-). This observation adds new information relevant to cat eye syndrome and partial trisomy of 22q. 2008 Wiley-Liss, Inc.

Biomedical applications of stereoregular poly(vinyl alcohol) micro- and nanoparticles

NASA Astrophysics Data System (ADS)

Lyoo, Won Seok; Kim, Joon Ho; Kim, Sam Soo; Ghim, Han Do

2002-11-01

Syndiotactic poly(vinyl alcohol) (PVA)/poly(vinyl pivalate/vinyl acetate) (P(VPi/VAc)) and atactic PVA/PVAc micro- and nanoparticles with skin/core structure have been prepared by heterogeneous saponification of P(VPi/VAc) and PVAc micro- and nanoparticles. Especially, to prepare P(VPi/VAc) and PVAc microparticles having various particle sizes and uniform particle size distribution, vinyl pivalate (VPi)/vinyl acetate (VAc) and VAc were suspension-polymerized using a low-temperature initiator, 2,2"-azobis(2,4-dimethylvaleronitrile). P(VPi/VAc) particles are promising precursor of stereoregular PVA embolic materials which can be introduced through catheters in the management of gastrointestinal bleeders, arteriovenous malformations, hemangiomas, and traumatic rupture of blood vessels. Monodisperse and/or nearly monodisperse P(VPi/VAc) and PVAc microparticles with various particle diameters were obtained by controlling suspension polymerization conditions. Monodisperse P(VPi/VAc) and PVAc microparticles having various particle sizes were partially saponified in the heterogeneous system. PVA/P(VPi/VAc) and PVA/PVAc microparticles having various tacticity and degree of saponification were produced by controlling various polymerization and saponification conditions. The coating of stereoregular PVA micro- and nanoparticles for drug release experiments was conducted with the strepo-avidin-alkaline phosphatase conjugate in variable conditions of pH value, coating buffer, and reaction temperature. Protein-coated syndiotactic PVA micro- and nanoparticles, which does not crosslinking, were more superior to controllability of drug release, durability, and dimensional stability to water and blood than atactic one.

Effect of Nanoparticle Surface on the HPLC Elution Profile of Liposomal Nanoparticles.

PubMed

Itoh, Naoki; Yamamoto, Eiichi; Santa, Tomofumi; Funatsu, Takashi; Kato, Masaru

2016-06-01

Nanoparticles have been used in diverse areas, and even broader applications are expected in the future. Since surface modification can influence the configuration and toxicity of nanoparticles, a rapid screening method is important to ensure nanoparticle quality. We examined the effect of the nanoparticle surface morphology on the HPLC elution profile using two types of 100-nm liposomal nanoparticles (AmBisome(Ⓡ) and DOXIL(Ⓡ)). These 100-nm-sized nanoparticles eluted before the holdup time (about 4 min), even when a column packed with particles with a relatively large pore size (30 nm) was used. The elution time of the nanoparticles increased with pegylation of the nanoparticles and protein adsorption to the nanoparticles; however, the nanoparticles still eluted before the holdup time. The results of this study indicate that HPLC is a suitable tool for rapid evaluation of the surface of liposomal nanoparticles.

Conference of University Administrators Conference Proceedings (12th, Surrey, England, March 21-23, 1985).

ERIC Educational Resources Information Center

Conference of Univ. Administrators.

Conference proceedings for the Conference of University Administrators include summaries of conference sessions, along with Austin Pearce's paper, "The Needs of Industry: What Are They?" Sessions focused on: forming a university company, financial diversification, financial modeling, stock exchange investment and universities, funding of…

10th international conference on high-occupancy vehicle systems : conference proceedings

DOT National Transportation Integrated Search

2001-08-01

This report documents the proceedings from the 10th International High-Occupancy Vehicle (HOV) Systems Conference held in Dallas, Texas on August 27-30, 2000. The Conference was sponsored by the Transportation Research Board (TRB), in cooperation wit...

Twitter use in physics conferences.

PubMed

Webb, Stephen

An analysis of Twitter use in 116 conferences suggests that the service is used more extensively at PACS10 conferences (those devoted to the physics of elementary particles and fields) and PACS90 conferences (those devoted to geophysics, astronomy, and astrophysics) than at conferences in other fields of physics. Furthermore, Twitter is used in a qualitatively different manner. A possible reason for these differences is discussed.

Stroke care conference.

PubMed

Watkins, Caroline

2016-10-28

The 11th UK Stroke Forum Conference, hosted by the Stroke Association, is the largest stroke conference in the UK. It aims to provide nurses and other healthcare professionals with opportunities to share learning and best practice in stroke care and rehabilitation.

Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying

NASA Astrophysics Data System (ADS)

Semaltianos, N. G.; Chassagnon, R.; Moutarlier, V.; Blondeau-Patissier, V.; Assoul, M.; Monteil, G.

2017-04-01

Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying.

PubMed

Semaltianos, N G; Chassagnon, R; Moutarlier, V; Blondeau-Patissier, V; Assoul, M; Monteil, G

2017-04-18

Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

38 CFR 59.123 - Conference.

Code of Federal Regulations, 2010 CFR

2010-07-01

... TO STATES FOR CONSTRUCTION OR ACQUISITION OF STATE HOMES § 59.123 Conference. At any time, VA may recommend that a conference (such as a design development conference) be held in VA Central Office in...

Terbium content affects the luminescence properties of ZrO2:Tb nanoparticles for mammary cancer imaging in mice

NASA Astrophysics Data System (ADS)

Kaszewski, Jarosław; Borgstrom, Emanuel; Witkowski, Bartłomiej S.; Wachnicki, Łukasz; Kiełbik, Paula; Slonska, Anna; Domino, Malgorzata A.; Narkiewicz, Urszula; Gajewski, Zdzislaw; Hochepied, Jean-François; Godlewski, Michał M.; Godlewski, Marek

2017-12-01

The use of nanoparticles in medicine is a rapidly growing research field with numerous potential applications, especially in the field of cancer diagnosis and therapy. Nanoparticles can be intrinsically diagnostic of therapeutic, or they can be conjugated with diagnostic or therapeutic compounds. Nanoparticles may also passively or actively target tumor cells specifically using the enhanced permeation and retention (EPR) effect, or the addition of targeting ligands to their surface. This may provide a diagnostic or/and therapeutic tools to target primary as well as metastatic tumors. The transport, distribution and toxicity of nanoparticles depends greatly on their size and composition, thus every new formulation needs to be extensively researched. This work was focused on the development of Tb-doped ZrO2 nanoparticles (NPs) for application in cancer imaging. Obtained nanoparticles were below 10 nm with very low influence of Tb concentration on size. Terbium stabilization of ZrO2 had influence on the luminescence properties of obtained material. Partially stabilized zirconium dioxide exhibited broad host related emission peaking at 500 nm, disappearing with the terbium content. We confirmed alimentary absorption and wide distribution of luminescent ZrO2:Tb nanoparticles in mice with their gradual accumulation in the experimentally induced mammary cancers. Furthermore, a high concentration of NPs was found within the lung metastases as opposed to healthy lung tissue, where no NPs-related signal was observed.

Conference call.

PubMed

2002-03-01

The RCN A&E Nursing Association, Black Country A&E professional development group and University of Wolverhampton school of health are holding the Emergency Nursing Research 2002 conference on March 6 in Wolverhampton. For more information, contact Alastair Gray by phone on 01902 307999 ext 2055 or by email at a.d.gray@wlv.ac.uk. Details available at www.man.ac.uk/rcn/conference/enrc2002.doc.

Effects of partial slip boundary condition and radiation on the heat and mass transfer of MHD-nanofluid flow

NASA Astrophysics Data System (ADS)

Abd Elazem, Nader Y.; Ebaid, Abdelhalim

2017-12-01

In this paper, the effect of partial slip boundary condition on the heat and mass transfer of the Cu-water and Ag-water nanofluids over a stretching sheet in the presence of magnetic field and radiation. Such partial slip boundary condition has attracted much attention due to its wide applications in industry and chemical engineering. The flow is basically governing by a system of partial differential equations which are reduced to a system of ordinary differential equations. This system has been exactly solved, where exact analytical expression has been obtained for the fluid velocity in terms of exponential function, while the temperature distribution, and the nanoparticles concentration are expressed in terms of the generalized incomplete gamma function. In addition, explicit formulae are also derived from the rates of heat transfer and mass transfer. The effects of the permanent parameters on the skin friction, heat transfer coefficient, rate of mass transfer, velocity, the temperature profile, and concentration profile have been discussed through tables and graphs.

Dual-excitation upconverting nanoparticle and quantum dot aptasensor for multiplexed food pathogen detection.

PubMed

Kurt, Hasan; Yüce, Meral; Hussain, Babar; Budak, Hikmet

2016-07-15

In this report, a dual-excitation sensing method was developed using aptamer-functionalized quantum dots and upconverting nanoparticles, exhibiting Stokes and anti-Stokes type excitation profiles, respectively. Conjugation of the aptamer-functionalized luminescent nanoparticles with the magnetic beads, comprising short DNA sequences that were partially complementary to the aptamer sequences, enabled facile separation of the analyte-free conjugates for fluorescent measurement. UV-Visible spectroscopy, Circular Dichroism spectroscopy, Dynamic Light Scattering and Polyacrylamide Gel Electrophoresis techniques were used to characterize the aptamer probes developed. The target-specific luminescent conjugates were applied for multiplex detection of model food pathogens, Salmonella typhimurium, and Staphylococcus aureus, in which the fluorescent emission spectra were obtained under UV excitation at 325nm for quantum dots and NIR excitation at 980nm for upconverting nanoparticles, respectively. The dual-excitation strategy was aimed to minimize cross-talk between the luminescent signals for multiplexed detection, and yielded limit of detection values of 16 and 28cfumL(-1) for Staphylococcus aureus, and Salmonella typhimurium, respectively. By employing a greater number of quantum dots and upconverting nanoparticles with non-overlapping fluorescent emissions, the proposed methodology might be exploited further to detect several analytes, simultaneously. Copyright © 2016 Elsevier B.V. All rights reserved.

Physico-chemical changes of ZnO nanoparticles with different size and surface chemistry under physiological pH conditions.

PubMed

Gwak, Gyeong-Hyeon; Lee, Won-Jae; Paek, Seung-Min; Oh, Jae-Min

2015-03-01

We studied the physico-chemical properties of ZnO nanoparticles under physiological pH conditions (gastric, intestinal and plasma) as functions of their size (20 and 70 nm) and surface chemistry (pristine, L-serine, or citrate coating). ZnO nanoparticles were dispersed in phosphate buffered saline under physiological pH conditions and aliquots were collected at specific time points (0.5, 1, 4, 10 and 24 h) for further characterization. The pH values of the aqueous ZnO colloids at each condition were in the neutral to slightly basic range and showed different patterns depending on the original size and surface chemistry of the ZnO nanoparticles. The gastric pH condition was found to significantly dissolve ZnO nanoparticles up to 18-30 wt%, while the intestinal or plasma pH conditions resulted in much lower dissolution amounts than expected. Based on the X-ray diffraction patterns and X-ray absorption spectra, we identified partial phase transition of the ZnO nanoparticles from wurtzite to Zn(OH)2 under the intestinal and plasma pH conditions. Using scanning electron microscopy, we verified that the overall particle size and morphology of all ZnO nanoparticles were maintained regardless of the pH. Copyright © 2015 Elsevier B.V. All rights reserved.

Cancer theranostics: Multifunctional gold nanoparticles for diagnostics and therapy

NASA Astrophysics Data System (ADS)

Conde, Joao Diogo Osorio de Castro

The use of gold nanoparticles (AuNPs) has been gaining momentum in molecular diagnostics due to their unique physico-chemical properties these systems present huge advantages, such as increased sensitivity, reduced cost and potential for single-molecule characterisation. Because of their versatility and easy of functionalisation, multifunctional AuNPs have also been proposed as optimal delivery systems for therapy (nanovectors). Being able to produce such systems would mean the dawn of a new age in theranostics (diagnostics and therapy)driven by nanotechnology vehicles. Nanotechnology can be exploit for cancer theranostics via the development of diagnostics systems such as colorimetric and imunoassays, and in therapy approaches through gene therapy, drug delivery and tumour targeting systems. The unique characteristics of nanoparticles in the nanometre range, such as high surface-tovolume ratio or shape/size-dependent optical properties, are drastically different from those of their bulk materials and hold pledge in the clinical field for disease therapeutics. This PhD project intends to optimise a gold-nanoparticle based technique for the detection of oncogenes' transcripts (c-Myc and BCR-ABL) that can be used for the evaluation of the expression profile in cancer cells, while simultaneously developing an innovative platform of multifunctional gold nanoparticles (tumour markers, cell penetrating peptides, fluorescent dyes) loaded with siRNA capable of silencing the selected proto-oncogenes, which can be used to evaluate the level of expression and determine the efficiency of silencing. In order to achieve this goal we developed effective conjugation strategies to combine, in a highly controlled way, biomolecules to the surface of AuNPs with specific functions such as: ssDNA oligos to detect specific sequences and for mRNA quantification; Biofunctional spacers: Poly(ethylene glycol) (PEG) spacers used to increase solubility and biocompatibility and confer chemical

Conference scene: DGVS spring conference 2009.

PubMed

Kolligs, Frank Thomas

2009-10-01

The 3rd annual DGVS Spring Conference of the German Society for Gastroenterology (Deutsche Gesellschaft für Verdauungs- und Stoffwechselkrankheiten) was held at the Seminaris Campus Hotel in Berlin, Germany, on 8-9 May, 2009. The conference was organized by Roland Schmid and Matthias Ebert from the Technical University of Munich, Germany. The central theme of the meeting was 'translational gastrointestinal oncology: towards personalized medicine and individualized therapy'. The conference covered talks on markers for diagnosis, screening and surveillance of colorectal cancer, targets for molecular therapy, response prediction in clinical oncology, development and integration of molecular imaging in gastrointestinal oncology and translational research in clinical trial design. Owing to the broad array of topics and limitations of space, this article will focus on biomarkers, response prediction and the integration of biomarkers into clinical trials. Presentations mentioned in this summary were given by Matthias Ebert (Technical University of Munich, Germany), Esmeralda Heiden (Epigenomics, Berlin, Germany), Frank Kolligs (University of Munich, Germany), Florian Lordick (University of Heidelberg, Germany), Hans Jorgen Nielsen (University of Copenhagen, Denmark), Anke Reinacher-Schick (University of Bochum, Germany), Christoph Röcken (University of Berlin, Germany), Wolff Schmiegel (University of Bochum, Germany) and Thomas Seufferlein (University of Halle, Germany).

New Approach for Gas Phase Synthesis and Growth Mechanism of MoS2 Fullerene-like Nanoparticles

NASA Astrophysics Data System (ADS)

Zak, Alla; Feldman, Yishay; Alperovich, Vladimir; Rosentsveig, Rita; Tenne, Reshef

2002-10-01

Inorganic fullerene-like (hollow onion-like) nanoparticles (IF) and nanotubes are of significant interest over the past few years due to their unusual crystallographic morphology and their interesting physical properties. The synthesis of inorganic fullerene-like spherical MoS2 nanoparticles (IF-MoS2) of 5-300nm in diameter was studied in the present work. This process is based on the previous formation of suboxide (MoO3-x) 5-300nm nanoparticles and their subsequent sulfidization. During the sulfidization process the overall geometrical parameters of the suboxide nanoparticles are preserved. The oxide nanoparticles were obtained in-situ by the condensation of the evaporated MoO3 powder precursor. The condensation was provoked not by cooling (conventional method for nano-size particle formation), but by a chemical reaction (partial reduction of the MoO3 vapor by hydrogen). In this case the vapor pressure of the product (MoO2) was much lower than that of the precursor (MoO3). Based on the comprehensive understanding of the IF-MoS2 growth mechanism from MoO3 powder, a gas phase reactor, which allowed reproducible preparation of a pure IF-MoS2 phase (up to 100mg/batch) with controllable sizes, is demonstrated. Further scale-up of this production is underway.

Ni3Si(Al)/a-SiOx core shell nanoparticles: characterization, shell formation, and stability

NASA Astrophysics Data System (ADS)

Pigozzi, G.; Mukherji, D.; Gilles, R.; Barbier, B.; Kostorz, G.

2006-08-01

We have used an electrochemical selective phase dissolution method to extract nanoprecipitates of the Ni3Si-type intermetallic phase from two-phase Ni-Si and Ni-Si-Al alloys by dissolving the matrix phase. The extracted nanoparticles are characterized by transmission electron microscopy, energy-dispersive x-ray spectrometry, x-ray powder diffraction, and electron powder diffraction. It is found that the Ni3Si-type nanoparticles have a core-shell structure. The core maintains the size, the shape, and the crystal structure of the precipitates that existed in the bulk alloys, while the shell is an amorphous phase, containing only Si and O (SiOx). The shell forms around the precipitates during the extraction process. After annealing the nanoparticles in nitrogen at 700 °C, the tridymite phase recrystallizes within the shell, which remains partially amorphous. In contrast, on annealing in air at 1000 °C, no changes in the composition or the structure of the nanoparticles occur. It is suggested that the shell forms after dealloying of the matrix phase, where Si atoms, the main constituents of the shell, migrate to the surface of the precipitates.

First Virtual Live Conference in Healthcare.

PubMed

Parthasarathi, Ramakrishnan; Gomes, Rachel M; Palanivelu, Praveen Raj; Senthilnathan, Palanisamy; Rajapandian, Subbiah; Venkatachalam, Ramasamy; Palanivelu, Chinnusamy

2017-07-01

Conferences and meetings bring together thousands of doctors from diverse locations. However, the traveling, accommodation, and arrangement of venues for conferences and meetings are expensive and a lot of time needs to be devoted to these logistics. The purpose of this article was to present our own virtual live conference experience using web conferencing and to briefly outline the basics and advantages of this technology in organization of healthcare conferences. Web conferencing technology was used to organize an international bariatric surgery conference, allowing a large number of attendees to participate and interact from wherever they were, using merely an Internet connection with a video player on their personal computers, laptops, or smartphones. A virtual live conference saves a lot of time and cost and simplifies the logistics needed to organize a learning conference with worldwide participation. As far as we know, this is the first report of a virtual live conference in healthcare. We see it as the future of organizing experts as well as medical teaching conferences.

7 CFR 1.167 - Conference.

Code of Federal Regulations, 2013 CFR

2013-01-01

... that conducting the conference by audio-visual telecommunication: (i) Is necessary to prevent prejudice.... If the Judge determines that a conference conducted by audio-visual telecommunication would... correspondence, the conference shall be conducted by audio-visual telecommunication unless the Judge determines...

7 CFR 1.167 - Conference.

Code of Federal Regulations, 2011 CFR

2011-01-01

... that conducting the conference by audio-visual telecommunication: (i) Is necessary to prevent prejudice.... If the Judge determines that a conference conducted by audio-visual telecommunication would... correspondence, the conference shall be conducted by audio-visual telecommunication unless the Judge determines...

7 CFR 1.167 - Conference.

Code of Federal Regulations, 2012 CFR

2012-01-01

... that conducting the conference by audio-visual telecommunication: (i) Is necessary to prevent prejudice.... If the Judge determines that a conference conducted by audio-visual telecommunication would... correspondence, the conference shall be conducted by audio-visual telecommunication unless the Judge determines...

7 CFR 1.167 - Conference.

Code of Federal Regulations, 2014 CFR

2014-01-01

... that conducting the conference by audio-visual telecommunication: (i) Is necessary to prevent prejudice.... If the Judge determines that a conference conducted by audio-visual telecommunication would... correspondence, the conference shall be conducted by audio-visual telecommunication unless the Judge determines...

7 CFR 1.167 - Conference.

Code of Federal Regulations, 2010 CFR

2010-01-01

... that conducting the conference by audio-visual telecommunication: (i) Is necessary to prevent prejudice.... If the Judge determines that a conference conducted by audio-visual telecommunication would... correspondence, the conference shall be conducted by audio-visual telecommunication unless the Judge determines...

Declining Enrollment. An NSBA Conference (Colorado Springs, Colorado, August 4-6, 1976). Conference Report.

ERIC Educational Resources Information Center

Florio, David H.

This report results from a National School Boards Association (NSBA) conference on declining enrollment and from a survey of state school boards associations conducted in advance of the conference. The conference drew school board leaders and school administrators together with population experts to achieve several purposes that are reflected in…

10th Conference on Bayesian Nonparametrics

DTIC Science & Technology

2016-05-08

RETURN YOUR FORM TO THE ABOVE ADDRESS. North Carolina State University 2701 Sullivan Drive Admin Srvcs III, Box 7514 Raleigh, NC 27695 -7514 ABSTRACT...the conference. The findings from the conference is widely disseminated. The conference web site displays slides of the talks presented in the...being published by the Electronic Journal of Statistics consisting of about 20 papers read at the conference. The conference web site displays

The Learning Conference

ERIC Educational Resources Information Center

Ravn, Ib

2007-01-01

Purpose: The purpose of this paper is to call attention to the fact that conferences for professionals rely on massive one-way communication and hence produce little learning for delegates--and to introduce an alternative, the "learning conference", that involves delegates in fun and productive learning processes.…

Synthesis of Zinc Oxide Nanoparticles and Their Effect on the Compressive Strength and Setting Time of Self-Compacted Concrete Paste as Cementitious Composites

PubMed Central

Arefi, Mohammad Reza; Rezaei-Zarchi, Saeed

2012-01-01

In the present study, the mechanical properties of self-compacting concrete were investigated after the addition of different amounts of ZnO nanoparticles. The zinc oxide nanoparticles, with an average particle size of about 30 nm, were synthesized and their properties studied with the help of a scanning electron microscope (SEM) and X-ray diffraction. The prepared nanoparticles were partially added to self-compacting concrete at different concentrations (0.05, 0.1, 0.2, 0.5 and 1.0%), and the mechanical (flexural and split tensile) strength of the specimens measured after 7, 14, 21 and 28 days, respectively. The present results have shown that the ZnO nanoparticles were able to improve the flexural strength of self-compacting concrete. The increased ZnO content of more than 0.2% could increase the flexural strength, and the maximum flexural and split tensile strength was observed after the addition of 0.5% nanoparticles. Finally, ZnO nanoparticles could improve the pore structure of the self-compacted concrete and shift the distributed pores to harmless and less-harmful pores, while increasing mechanical strength. PMID:22605981

Synthesis of zinc oxide nanoparticles and their effect on the compressive strength and setting time of self-compacted concrete paste as cementitious composites.

PubMed

Arefi, Mohammad Reza; Rezaei-Zarchi, Saeed

2012-01-01

In the present study, the mechanical properties of self-compacting concrete were investigated after the addition of different amounts of ZnO nanoparticles. The zinc oxide nanoparticles, with an average particle size of about 30 nm, were synthesized and their properties studied with the help of a scanning electron microscope (SEM) and X-ray diffraction. The prepared nanoparticles were partially added to self-compacting concrete at different concentrations (0.05, 0.1, 0.2, 0.5 and 1.0%), and the mechanical (flexural and split tensile) strength of the specimens measured after 7, 14, 21 and 28 days, respectively. The present results have shown that the ZnO nanoparticles were able to improve the flexural strength of self-compacting concrete. The increased ZnO content of more than 0.2% could increase the flexural strength, and the maximum flexural and split tensile strength was observed after the addition of 0.5% nanoparticles. Finally, ZnO nanoparticles could improve the pore structure of the self-compacted concrete and shift the distributed pores to harmless and less-harmful pores, while increasing mechanical strength.

Large Uptake of Titania and Iron Oxide Nanoparticles in the Nucleus of Lung Epithelial Cells as Measured by Raman Imaging and Multivariate Classification

PubMed Central

Ahlinder, Linnea; Ekstrand-Hammarström, Barbro; Geladi, Paul; Österlund, Lars

2013-01-01

It is a challenging task to characterize the biodistribution of nanoparticles in cells and tissue on a subcellular level. Conventional methods to study the interaction of nanoparticles with living cells rely on labeling techniques that either selectively stain the particles or selectively tag them with tracer molecules. In this work, Raman imaging, a label-free technique that requires no extensive sample preparation, was combined with multivariate classification to quantify the spatial distribution of oxide nanoparticles inside living lung epithelial cells (A549). Cells were exposed to TiO2 (titania) and/or α-FeO(OH) (goethite) nanoparticles at various incubation times (4 or 48 h). Using multivariate classification of hyperspectral Raman data with partial least-squares discriminant analysis, we show that a surprisingly large fraction of spectra, classified as belonging to the cell nucleus, show Raman bands associated with nanoparticles. Up to 40% of spectra from the cell nucleus show Raman bands associated with nanoparticles. Complementary transmission electron microscopy data for thin cell sections qualitatively support the conclusions. PMID:23870252

Selected papers from the Fourth Annual q-bio Conference on Cellular Information Processing.

PubMed

Nemenman, Ilya; Faeder, James R; Hlavacek, William S; Jiang, Yi; Wall, Michael E; Zilman, Anton

2011-10-01

This special issue consists of 11 original papers that elaborate on work presented at the Fourth Annual q-bio Conference on Cellular Information Processing, which was held on the campus of St John's College in Santa Fe, New Mexico, USA, 11-14 August 2010. Now in its fourth year, the q-bio conference has changed considerably over time. It is now well established and a major event in systems biology. The 2010 conference saw attendees from all continents (except Antarctica!) sharing novel results and participating in lively discussions at both the oral and poster sessions. The conference was oversubscribed and grew to 27 contributed talks, 16 poster spotlights and 137 contributed posters. We deliberately decreased the number of invited speakers to 21 to leave more space for contributed presentations, and the attendee feedback confirmed that the choice was a success. Although the q-bio conference has grown and matured, it has remained true to the original goal of being an intimate and dynamic event that brings together modeling, theory and quantitative experimentation for the study of cell regulation and information processing. Funded in part by a grant from NIGMS and by DOE funds through the Los Alamos National Laboratory Directed Research and Development program, the conference has continued to exhibit youth and vigor by attracting (and partially supporting) over 100 undergraduate, graduate and postdoctoral researchers. The associated q-bio summer school, which precedes the conference each year, further emphasizes the development of junior scientists and makes q-bio a singular event in its impact on the future of quantitative biology. In addition to an increased international presence, the conference has notably diversified its demographic representation within the USA, including increased participation from the southeastern corner of the country. One big change in the conference this year is our new publication partner, Physical Biology. Although we are very

Synthesis and Catalytic Activity of Pluronic Stabilized Silver-Gold Bimetallic Nanoparticles.

PubMed

Holden, Megan S; Nick, Kevin E; Hall, Mia; Milligan, Jamie R; Chen, Qiao; Perry, Christopher C

2014-01-01

In this report, we demonstrate a rapid, simple, and green method for synthesizing silver-gold (Ag-Au) bimetallic nanoparticles (BNPs). We used a novel modification to the galvanic replacement reaction by suspending maltose coated silver nanoparticles (NPs) in ≈ 2% aqueous solution of EO 100 PO 65 EO 100 (Pluronic F127) prior to HAuCl 4 addition. The Pluronic F127 stabilizes the BNPs, imparts biocompatibility, and mitigates the toxicity issues associated with other surfactant stabilizers. BNPs with higher Au:Ag ratios and, subsequently, different morphologies were successfully synthesized by increasing the concentration of gold salt added to the Ag NP seeds. These BNPs have enhanced catalytic activities than typically reported for monometallic Au or Ag NPs (∼ 2-10 fold) of comparable sizes in the sodium borohydride reduction of 4-nitrophenol. The 4-nitrophenol reduction rates were highest for partially hollow BNP morphologies.

PREFACE: International Conference on Dynamics of Systems on the Nanoscale (DySoN 2012)

NASA Astrophysics Data System (ADS)

Solov'yov, Andrey V.

2013-06-01

Conference logo The Second International Conference 'Dynamics of Systems on the Nanoscale' (DySoN 2012) took place in Saint Petersburg, Russia between 30 September and 4 October 2012. The venue was the Courtyard by Marriott St Petersburg Vasilievsky Hotel, 2nd line of Vasilievsky Island 61/30A, 199178. The conference was organized by the Frankfurt Institute for Advanced Studies - Goethe University, A F Ioffe Physical-Technical Institute and Saint Petersburg State Polytechnic University. This DySoN conference has been built upon a series of International Symposia 'Atomic Cluster Collisions: structure and dynamics from the nuclear to the biological scale' (ISACC 2003, ISACC 2007, ISACC 2008, ISACC 2009 and ISACC 2011). During these meetings it has become clear that there is a need for an interdisciplinary conference covering a broader range of topics than just atomic cluster collisions, related to the Dynamics of Systems on a Nanoscale. Therefore, in 2010 it was decided to launch a new conference series under the title 'Dynamics of Systems on the Nanoscale'. The first DySoN conference took place at the National Research Council, Rome, Italy in 2010. The DySoN 2012 is the second conference in this series. The DySoN 2012 Conference promoted the growth and exchange of interdisciplinary scientific information on the structure, formation and dynamics of animate and inanimate matter on the nanometer scale. There are many examples of complex many-body systems of micro- and nanometer scale size exhibiting unique features, properties and functions. These systems may have very different nature and origin, e.g. atomic and molecular clusters, nanoobjects, ensembles of nanoparticles, nanostructures, biomolecules, biomolecular and mesoscopic systems. A detailed understanding of the structure and dynamics of these systems on the nanometer scale is an important fundamental task, the solution of which is necessary in numerous applications of nano- and biotechnology, material science

Iron oxide nanoparticles surface coating and cell uptake affect biocompatibility and inflammatory responses of endothelial cells and macrophages

NASA Astrophysics Data System (ADS)

Orlando, Antonina; Colombo, Miriam; Prosperi, Davide; Gregori, Maria; Panariti, Alice; Rivolta, Ilaria; Masserini, Massimo; Cazzaniga, Emanuela

2015-09-01

Engineered iron oxide nanoparticles (IONP) offer the possibility of a wide range of medical uses, from clinical imaging to magnetically based hyperthermia for tumor treatment. These applications require their systemic administration in vivo. An important property of nanoparticles is their stability in biological media. For this purpose, a multicomponent nanoconstruct combining high colloidal stability and improved physical properties was synthesized and characterized. IONP were coated with an amphiphilic polymer (PMA), which confers colloidal stability, and were pegylated in order to obtain the nanoconstruct PEG-IONP-PMA. The aim of this study was to utilize cultured human endothelial cells (HUVEC) and murine macrophages, taken as model of cells exposed to NP after systemic administration, to assess the biocompatibility of PEG-IONP-PMA (23.1 ± 1.4 nm) or IONP-PMA (15.6 ± 3.4 nm). PEG-IONP-PMA, tested at different concentrations as high as 20 μg mL-1, exhibited no cytotoxicity or inflammatory responses. By contrast, IONP-PMA showed a concentration-dependent increase of cytotoxicity and of TNF-α production by macrophages and NO production by HUVECs. Cell uptake analysis suggested that after PEGylation, IONP were less internalized either by macrophages or by HUVEC. These results suggest that the choice of the polymer and the chemistry of surface functionalization are a crucial feature to confer to IONP biocompatibility.

Interior engineering of a viral nanoparticle and its tumor homing properties

PubMed Central

Wen, Amy M.; Shukla, Sourabh; Saxena, Pooja; Aljabali, Alaa A.A.; Yildiz, Ibrahim; Dey, Sourav; Mealy, Joshua E.; Yang, Alice C.; Evans, David J.; Lomonossoff, George P.; Steinmetz, Nicole F.

2012-01-01

The development of multifunctional nanoparticles for medical applications is of growing technological interest. A single formulation containing imaging and/or drug moieties that is also capable of preferential uptake in specific cells would greatly enhance diagnostics and treatments. There is growing interest in plant-derived viral nanoparticles (VNPs) and establishing new platform technologies based on these nanoparticles inspired by nature. Cowpea mosaic virus (CPMV) serves as the standard model for VNPs. Although exterior surface modification is well known and has been comprehensively studied, little is known of interior modification. Additional functionality conferred by the capability for interior engineering would be of great benefit toward the ultimate goal of targeted drug delivery. Here, we examined the capacity of empty CPMV (eCPMV) particles devoid of RNA to encapsulate a wide variety of molecules. We systematically investigated the conjugation of fluorophores, biotin affinity tags, large molecular weight polymers such as polyethylene glycol (PEG), and various peptides through targeting reactive cysteines displayed selectively on the interior surface. Several methods are described that mutually confirm specific functionalization of the interior. Finally, CPMV and eCPMV were labeled with near-infrared fluorophores and studied side-by-side in vitro and in vivo. Passive tumor targeting via the enhanced permeability and retention effect and optical imaging were confirmed using a preclinical mouse model of colon cancer. The results of our studies lay the foundation for the development of the eCPMV platform in a range of biomedical applications. PMID:23121655

Active Silver Nanoparticles for Wound Healing

PubMed Central

Rigo, Chiara; Ferroni, Letizia; Tocco, Ilaria; Roman, Marco; Munivrana, Ivan; Gardin, Chiara; Cairns, Warren R. L.; Vindigni, Vincenzo; Azzena, Bruno; Barbante, Carlo; Zavan, Barbara

2013-01-01

In this preliminary study, the silver nanoparticle (Ag NP)-based dressing, Acticoat™ Flex 3, has been applied to a 3D fibroblast cell culture in vitro and to a real partial thickness burn patient. The in vitro results show that Ag NPs greatly reduce mitochondrial activity, while cellular staining techniques show that nuclear integrity is maintained, with no signs of cell death. For the first time, transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS) analyses were carried out on skin biopsies taken from a single patient during treatment. The results show that Ag NPs are released as aggregates and are localized in the cytoplasm of fibroblasts. No signs of cell death were observed, and the nanoparticles had different distributions within the cells of the upper and lower dermis. Depth profiles of the Ag concentrations were determined along the skin biopsies. In the healed sample, most of the silver remained in the surface layers, whereas in the unhealed sample, the silver penetrated more deeply. The Ag concentrations in the cell cultures were also determined. Clinical observations and experimental data collected here are consistent with previously published articles and support the safety of Ag NP-based dressing in wound treatment. PMID:23455461

Intermetallic nanoparticles

DOEpatents

Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules

2015-07-14

A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

Intermetallic nanoparticles

DOEpatents

Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules L.

2015-11-20

A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

Intermetallic nanoparticles

DOEpatents

Singh, Dileep; Yusufoglu, Yusuf; Timofeeva, Elena; Routbort, Jules L.

2017-01-03

A process for preparing intermetallic nanoparticles of two or more metals is provided. In particular, the process includes the steps: a) dispersing nanoparticles of a first metal in a solvent to prepare a first metal solution, b) forming a reaction mixture with the first metal solution and a reducing agent, c) heating the reaction mixture to a reaction temperature; and d) adding a second metal solution containing a salt of a second metal to the reaction mixture. During this process, intermetallic nanoparticles, which contain a compound with the first and second metals are formed. The intermetallic nanoparticles with uniform size and a narrow size distribution is also provided. An electrochemical device such as a battery with the intermetallic nanoparticles is also provided.

Next generation radiotherapy biomaterials loaded with high-Z nanoparticles

NASA Astrophysics Data System (ADS)

Cifter, Gizem

This research investigates the dosimetric feasibility of using high-Z nanoparticles as localized radiosensitizers to boost the dose to the residual tumor cells during accelerated partial breast irradiation while minimizing the dose to surrounding healthy tissue. Analytical microdosimetry calculations were carried out to calculate dose enhancement (DEF) in the presence of high-Z nanoparticles. It has been proposed that routinely used inert radiotherapy (RT) biomaterials (e.g. fiducials, spacers) can be upgraded to smarter ones by coating/loading them with radiosensitizing gold nanoparticles (GNPs), for sustained in-situ release after implantation to enhance RT. Prototype smart biomaterials were produced by incorporating the GNPs in poly (D,L-lactide-co-glycolide) (PLGA) polymer millirods during the gel phase of production. In vitro release of GNPs was monitored over time by optical/spectroscopy methods as a function of various design parameters. The prototype smart biomaterials displayed sustained customizable release of NPs in-vitro, reaching a burst release profile approximately after 25 days. The results also show that customizable release profiles can be achievable by varying GNP concentrations that are embedded within smart biomaterials, as well as other design parameters. This would potentially allow customizable local dose boost resulting in diverse treatment planning opportunities for individual cases. Considered together, the results provide preliminary data for development of next generation of RT biomaterials, which can be employed at no additional inconvenience to RT patients.

Major Biomass Conference

Science.gov Websites

Top Scientists, Industry and Government Leaders to Gather for Major Biomass Conference America, South America and Europe will focus on building a sustainable, profitable biomass business at the Third Biomass Conference of the Americas in Montreal. Scheduled presentations will cover all biomass

Joint conference.

PubMed

1999-10-01

The Irish Emergency Nurses Association and RCN A&E Nursing Association are holding a conference in Newry, Co Down on November 25. Topics include an update on the Faculty of Emergency Nursing, the management of chest trauma, obstetric emergencies, management of pre-tibial lacerations, and what's hip on the drug scene. Cost: £50 RCN members; £70 for nonmembers (includes dinner and disco). Conference only £35. Contact, Claire Morrissy, RCN, 17 Windsor Avenue, Belfast. Tel 01232-668236.

pH-responsive thiolated chitosan nanoparticles for oral low-molecular weight heparin delivery: in vitro and in vivo evaluation.

PubMed

Fan, Bo; Xing, Yang; Zheng, Ying; Sun, Chuan; Liang, Guixian

2016-01-01

The aim of present study was to investigate a pH-responsive and mucoadhesive nanoparticle system for oral bioavailability enhancement of low-molecular weight heparin (LMWH). The thioglycolic acid (TGA) was first covalently attached to chitosan (CS) with 396.97 ± 54.54 μmol thiol groups per gram of polymer and then the nanoparticles were prepared with thiolated chitosan (TCS) and pH-sensitive polymer hydroxypropyl methylcellulose phthalate (HPMCP) by ionic cross-linking method. The obtained nanoparticles were characterized for the shape, particle size, zeta potential, drug entrapment efficiency and loading capacity. In vitro results revealed the acid stability of pH-responsive nanoparticles, which had a significant control over LMWH release and could effectively protect entrapped drugs in simulated gastric conditions. By the attachment of the thiol ligand, an improvement of permeation-enhancing effect on freshly excised carp intestine (1.86-fold improvement) could be found. The mucoadhesive properties were evaluated using fluorescently labeled TCS or CS nanoparticles. As compared with the controls, a significant improvement of mucoadhesion on rat intestinal mucosa was observed in TCS/HPMCP nanoparticles via confocal laser scanning microscopy. The activated partial thromboplastin time (APTT) was significantly prolonged and an increase in the oral bioavailability of LMWH was turned out to be pronounced after oral delivered LMWH-loaded TCS/HPMCP nanoparticles in rats, which suggested enhanced anticoagulant effects and improved absorption of LMWH. In conclusion, pH-responsive TCS/HPMCP nanoparticles hold promise for oral delivery of LMWH.

Physicochemical properties and in vitro cytotoxicity of iron oxide-based nanoparticles modified with antiangiogenic and antitumor peptide A7R

NASA Astrophysics Data System (ADS)

Niescioruk, Anna; Nieciecka, Dorota; Puszko, Anna K.; Królikowska, Agata; Kosson, Piotr; Perret, Gerard Y.; Krysinski, Pawel; Misicka, Aleksandra

2017-05-01

Superparamagnetic iron oxide-based nanoparticles (SPIONs) are promising carriers as targeted drug delivery vehicles, because they can be guided to their target with the help of an external magnetic field. Functionalization of nanoparticles' surface with molecules, which bind with high affinity to receptors on target tissue significantly facilitates delivery of coated nanoparticles to their targeted site. Here, we demonstrate conjugation of an antiangiogenic and antitumor peptide ATWLPPR (A7R) to SPIONs modified with sebacic acid (SPIONs-SA). Successful conjugation was confirmed by various analytical techniques (FTIR, SERS, SEM-EDS, TEM, TGA). Cell cytotoxicity studies, against two cell lines (HUVEC and MDA-MB-231) indicated that SPIONs modified with A7R reduced HUVEC cell viability at concentrations higher than 0.01 mg Fe/mL, in comparison to cells that were exposed to either the nanoparticles modified with sebacic acid or A7R peptide solely, what might be partially caused by a process of internalization.

Dress Codes and the Academic Conference: McCulloch's Iron Laws of Conferences

ERIC Educational Resources Information Center

McCulloch, Alistair

2018-01-01

Despite being a staple of academic life (or perhaps because it is so taken-for-granted), the academic conference has been generally under-utilised as a site for academic research. Using participant observation as its methodology, this article draws on a long career of conference attendance to present two iron laws of conferences which address the…

PREFACE: Quark Matter 2006 Conference

NASA Astrophysics Data System (ADS)

Ma, Yu-Gang; Wang, En-Ke; Cai, Xu; Huang, Huan-Zhong; Wang, Xin-Nian; Zhu, Zhi-Yuan

2007-07-01

The Quark Matter 2006 conference was held on 14 20 November 2006 at the Shanghai Science Hall of the Shanghai Association of Sciences and Technology in Shanghai, China. It was the 19th International Conference on Ultra-Relativistic Nucleus Nucleus Collisions. The conference was organized jointly by SINAP (Shanghai Institute of Applied Physics, Chinese Academy of Sciences (CAS)) and CCNU (Central China Normal University, Wuhan). Over 600 scientists from 32 countries in five continents attended the conference. This is the first time that China has hosted such a premier conference in the field of relativistic heavy-ion collisions, an important event for the Chinese high energy nuclear physics community. About one half of the conference participants are junior scientists—a clear indication of the vigor and momentum for this field, in search of the fundamental nature of the nuclear matter at extreme conditions. Professor T D Lee, honorary chair of the conference and one of the founders of the quark matter research, delivered an opening address with his profound and philosophical remarks on the recent discovery of the nature of strongly-interacting quark-gluon-plasma (sQGP). Professor Hongjie Xu, director of SINAP, gave a welcome address to all participants on behalf of the two hosting institutions. Dr Peiwen Ji, deputy director of the Mathematics and Physics Division of the Natural Science Foundation of China (NSFC), also addressed the conference participants and congratulated them on the opening of the conference. Professor Mianheng Jiang, vice president of the Chinese Academy of Sciences (CAS), gave a concise introduction about the CAS as the premier research institution in China. He highlighted continued efforts at CAS to foster international collaborations between China and other nations. The Quark Matter 2006 conference is an example of such a successful collaboration between high energy nuclear physicists in China and other nations all over the world. The

Silver Nanoparticles

NASA Astrophysics Data System (ADS)

Khaydarov, R. R.; Khaydarov, R. A.; Estrin, Y.; Evgrafova, S.; Scheper, T.; Endres, C.; Cho, S. Y.

The bactericidal effect of silver nanoparticles obtained by a novel electrochemical method on Escherichia coli, Staphylococcus aureus, Aspergillus niger and Penicillium phoeniceum cultures has been studied. The tests conducted have demonstrated that synthesized silver nanoparticles — when added to water paints or cotton fabrics — show a pronounced antibacterial/antifungal effect. It was shown that smaller silver nanoparticles have a greater antibacterial/antifungal efficacy. The paper also provides a review of scientific literature with regard to recent developments in the field of toxicity of silver nanoparticles and its effect on environment and human health.

PREFACE: Annual Conference on Functional Materials and Nanotechnologies - FM&NT 2011

NASA Astrophysics Data System (ADS)

Sternberg, Andris; Muzikante, Inta; Zicans, Janis

2011-06-01

The International Conference Functional Materials and Nanotechnologies (FM&NT-2011) was held in Riga, 5-8 April 2011 in the Institute of Solid State Physics, University of Latvia (ISSP LU). The conference was organized in co-operation with projects ERANET 'MATERA' and National Research programme in Materials Science and Information Technologies. The purpose of the conference was to bring together scientists, engineers and students from universities, research institutes and related industrial companies active in the field of advanced material science and materials technologies trends and future activities. Scientific themes covered in the conference are: theoretical research and modelling of processes and materials; materials for energetics, renewable energy technologies and phtovoltaics; multifunctional inorganic, organic and hybrid materials for photonic, micro and nanoelectronic applications and innovative methods for research of nanostructures; advanced technologies for synthesis and research of nanostructured materials, nanoparticles, thin films and coatings; application of innovative materials in science and economics. The number of registered participants from 17 countries was nearly 300. During three days of the conference 22 invited, 69 oral reports and 163 posters were presented. 40 papers, based on these reports, are included in this volume of IOP Conference Series: Materials Science and Engineering. Additional information about FM&NT-2011 is available in its homepage http://www.fmnt.lu.lv. The Organizing Committee would like to thank all speakers, contributors, session chairs, referees and meeting staff for their efforts in making the FM&NT-2011 successful. The Organizing Committee sincerely hopes that that the conference gave all participants new insights into the widespread development of functional materials and nanotechnologies and would enhance the circulation of information released at the meeting. Andris Sternberg Inta Muzikante Janis Zicans

GE STEM Teacher's Conference

NASA Image and Video Library

2017-07-13

Teachers participate in the Rocketry Engineering Design Challenge during the 2017 GE Foundation High School STEM Integration Conference at the Center for Space Education at NASA's Kennedy Space Center. High school teachers from across the country took part in the week-long conference, which is designed to explore effective ways for teachers, schools and districts from across the country to integrate STEM throughout the curriculum. The conference is a partnership between GE Foundation and the National Science Teachers Association.

Interaction of nanoparticles with proteins: relation to bio-reactivity of the nanoparticle.

PubMed

Saptarshi, Shruti R; Duschl, Albert; Lopata, Andreas L

2013-07-19

Interaction of nanoparticles with proteins is the basis of nanoparticle bio-reactivity. This interaction gives rise to the formation of a dynamic nanoparticle-protein corona. The protein corona may influence cellular uptake, inflammation, accumulation, degradation and clearance of the nanoparticles. Furthermore, the nanoparticle surface can induce conformational changes in adsorbed protein molecules which may affect the overall bio-reactivity of the nanoparticle. In depth understanding of such interactions can be directed towards generating bio-compatible nanomaterials with controlled surface characteristics in a biological environment. The main aim of this review is to summarise current knowledge on factors that influence nanoparticle-protein interactions and their implications on cellular uptake.

Recent Advances in Inorganic Nanoparticle-Based NIR Luminescence Imaging: Semiconductor Nanoparticles and Lanthanide Nanoparticles.

PubMed

Kim, Dokyoon; Lee, Nohyun; Park, Yong Il; Hyeon, Taeghwan

2017-01-18

Several types of nanoparticle-based imaging probes have been developed to replace conventional luminescent probes. For luminescence imaging, near-infrared (NIR) probes are useful in that they allow deep tissue penetration and high spatial resolution as a result of reduced light absorption/scattering and negligible autofluorescence in biological media. They rely on either an anti-Stokes or a Stokes shift process to generate luminescence. For example, transition metal-doped semiconductor nanoparticles and lanthanide-doped inorganic nanoparticles have been demonstrated as anti-Stokes shift-based agents that absorb NIR light through two- or three-photon absorption process and upconversion process, respectively. On the other hand, quantum dots (QDs) and lanthanide-doped nanoparticles that emit in NIR-II range (∼1000 to ∼1350 nm) were suggested as promising Stokes shift-based imaging agents. In this topical review, we summarize and discuss the recent progress in the development of inorganic nanoparticle-based luminescence imaging probes working in NIR range.

Controlling energy transfer between multiple dopants within a single nanoparticle

PubMed Central

DiMaio, Jeffrey R.; Sabatier, Clément; Kokuoz, Baris; Ballato, John

2008-01-01

Complex core-shell architectures are implemented within LaF3 nanoparticles to allow for a tailored degree of energy transfer (ET) between different rare earth dopants. By constraining specific dopants to individual shells, their relative distance to one another can be carefully controlled. Core-shell LaF3 nanoparticles doped with Tb3+ and Eu3+ and consisting of up to four layers were synthesized with an outer diameter of ≈10 nm. It is found that by varying the thicknesses of an undoped layer between a Tb3+-doped layer and a Eu3+-doped layer, the degree of ET can be engineered to allow for zero, partial, or total ET from a donor ion to an acceptor ion. More specifically, the ratio of the intensities of the 541-nm Tb3+ and 590 nm Eu3+ peaks was tailored from <0.2 to ≈2.4 without changing the overall composition of the particles but only by changing the internal structure. Further, the emission spectrum of a blend of singly doped nanoparticles is shown to be equivalent to the spectra of co-doped particles when a core-shell configuration that restricts ET is used. Beyond simply controlling ET, which can be limiting when designing materials for optical applications, this approach can be used to obtain truly engineered spectral features from nanoparticles and composites made from them. Further, it allows for a single excitation source to yield multiple discrete emissions from numerous lanthanide dopants that heretofore would have been quenched in a more conventional active optical material. PMID:18250307

Glutathione S-transferases as antioxidant defence agents confer pyrethroid resistance in Nilaparvata lugens.

PubMed Central

Vontas, J G; Small, G J; Hemingway, J

2001-01-01

Selection of a laboratory colony of the brown planthopper Nilaparvata lugens with the pyrethroids permethrin and lambda-cyhalothrin increased its resistance to both insecticides. Biochemical analysis and synergistic studies with metabolic inhibitors indicated that elevated glutathione S-transferases (GSTs) with a predominant peroxidase activity conferred resistance to both pyrethroids, whereas esterases conferred part of the resistance to permethrin. Purified esterases hydrolysed permethrin at a slow rate, but incubation of either pyrethroid or their primary metabolites with partially purified GSTs had no effect on the metabolic profile. Although GSTs were sensitive to inhibition by both pyrethroids, they did not serve as binding proteins, as previously hypothesized [Grant and Matsumura (1988) Insect Biochem. 18, 615-622]. We demonstrate that pyrethroids, in addition to their neurotoxic effect, induce oxidative stress and lipid peroxidation in insects. Pyrethroid exposure induced lipid peroxides, protein oxidation and depleted reduced glutathione. Elevated GSTs in the resistant strains attenuated the pyrethroid-induced lipid peroxidation and reduced mortality, whereas their in vivo inhibition eliminated their protective role. We therefore hypothesize that the main role of elevated GSTs in conferring resistance in N. lugens is through protecting tissues from oxidative damage. Our study extends the GSTs' range of efficacy to pyrethroid insecticides and possibly explains the role of elevated GSTs in other pyrethroid-resistant insects. PMID:11415437

76 FR 60017 - Technical Conference on Penalty Guidelines; Notice of Technical Conference on Penalty Guidelines

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-28

... Conference on Penalty Guidelines; Notice of Technical Conference on Penalty Guidelines The staff of the... the Penalty Guidelines, which the Commission issued on September 17, 2010.\\1\\ The conference will be... impact of the Penalty Guidelines on compliance and enforcement matters. More information on the topics to...

Conference Abstracts: AEDS '82.

ERIC Educational Resources Information Center

Journal of Computers in Mathematics and Science Teaching, 1982

1982-01-01

Abstracts from nine selected papers presented at the 1982 Association for Educational Data Systems (AEDS) conference are provided. Copies of conference proceedings may be obtained for fifteen dollars from the Association. (MP)

PRACTICAL GUIDE TO CONFERENCE LEADERSHIP.

ERIC Educational Resources Information Center

MORGAN, JOHN S.

THIS GUIDE TO CONFERENCE LEADERSHIP BEGINS WITH A CHAPTER ON LEADERSHIP PSYCHOLOGY AND GOES ON TO PRESENT OUTLINES FOR RUNNING CONFERENCES. THE LEADER PREPARES FOR THE MEETING BY COLLECTING FACTS ON THE SUBJECT, PREPARING AN OUTLINE, KNOWING THE PARTICIPANTS, MAKING PHYSICAL ARRANGEMENTS, AND WRITING THE TENTATIVE SUMMARY. IN THE CONFERENCE HE…

Conducting survey research at nursing conferences.

PubMed

Sleutel, M R

2001-01-01

Conferences can provide large numbers of potential subjects in one location, yet there is little published guidance on how to collect data at a conference site. A computer search revealed no citations on this topic. This article outlines a systematic strategy to plan and perform research at conferences. This article provides a step-by-step process to guide researchers in planning and conducting survey research at conferences. Initial components in planning data collection at a conference include making a timeline and getting permission. Detailed advanced planning involves specific strategies for attracting participants, and for distributing and collecting the questionnaires. Travel provisions and on-site logistical approaches are explained, followed by suggestions for post-conference activities.

Multimodality Imaging with Silica-Based Targeted Nanoparticle Platforms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jason S. Lewis

2012-04-09

Objectives: To synthesize and characterize a C-Dot silica-based nanoparticle containing 'clickable' groups for the subsequent attachment of targeting moieties (e.g., peptides) and multiple contrast agents (e.g., radionuclides with high specific activity) [1,2]. These new constructs will be tested in suitable tumor models in vitro and in vivo to ensure maintenance of target-specificity and high specific activity. Methods: Cy5 dye molecules are cross-linked to a silica precursor which is reacted to form a dye-rich core particle. This core is then encapsulated in a layer of pure silica to create the core-shell C-Dot (Figure 1) [2]. A 'click' chemistry approach has beenmore » used to functionalize the silica shell with radionuclides conferring high contrast and specific activity (e.g. 64Cu and 89Zr) and peptides for tumor targeting (e.g. cRGD and octreotate) [3]. Based on the selective Diels-Alder reaction between tetrazine and norbornene, the reaction is bioorthogonal, highyielding, rapid, and water-compatible. This radiolabeling approach has already been employed successfully with both short peptides (e.g. octreotate) and antibodies (e.g. trastuzumab) as model systems for the ultimate labeling of the nanoparticles [1]. Results: PEGylated C-Dots with a Cy5 core and labeled with tetrazine have been synthesized (d = 55 nm, zeta potential = -3 mV) reliably and reproducibly and have been shown to be stable under physiological conditions for up to 1 month. Characterization of the nanoparticles revealed that the immobilized Cy5 dye within the C-Dots exhibited fluorescence intensities over twice that of the fluorophore alone. The nanoparticles were successfully radiolabeled with Cu-64. Efforts toward the conjugation of targeting peptides (e.g. cRGD) are underway. In vitro stability, specificity, and uptake studies as well as in vivo imaging and biodistribution investigations will be presented. Conclusions: C-Dot silica-based nanoparticles offer a robust, versatile, and

Ni(3)Si(Al)/a-SiO(x) core-shell nanoparticles: characterization, shell formation, and stability.

PubMed

Pigozzi, G; Mukherji, D; Gilles, R; Barbier, B; Kostorz, G

2006-08-28

We have used an electrochemical selective phase dissolution method to extract nanoprecipitates of the Ni(3)Si-type intermetallic phase from two-phase Ni-Si and Ni-Si-Al alloys by dissolving the matrix phase. The extracted nanoparticles are characterized by transmission electron microscopy, energy-dispersive x-ray spectrometry, x-ray powder diffraction, and electron powder diffraction. It is found that the Ni(3)Si-type nanoparticles have a core-shell structure. The core maintains the size, the shape, and the crystal structure of the precipitates that existed in the bulk alloys, while the shell is an amorphous phase, containing only Si and O (SiO(x)). The shell forms around the precipitates during the extraction process. After annealing the nanoparticles in nitrogen at 700 °C, the tridymite phase recrystallizes within the shell, which remains partially amorphous. In contrast, on annealing in air at 1000 °C, no changes in the composition or the structure of the nanoparticles occur. It is suggested that the shell forms after dealloying of the matrix phase, where Si atoms, the main constituents of the shell, migrate to the surface of the precipitates.

An adenovirus-vectored nasal vaccine confers rapid and sustained protection against anthrax in a single-dose regimen.

PubMed

Zhang, Jianfeng; Jex, Edward; Feng, Tsungwei; Sivko, Gloria S; Baillie, Leslie W; Goldman, Stanley; Van Kampen, Kent R; Tang, De-chu C

2013-01-01

Bacillus anthracis is the causative agent of anthrax, and its spores have been developed into lethal bioweapons. To mitigate an onslaught from airborne anthrax spores that are maliciously disseminated, it is of paramount importance to develop a rapid-response anthrax vaccine that can be mass administered by nonmedical personnel during a crisis. We report here that intranasal instillation of a nonreplicating adenovirus vector encoding B. anthracis protective antigen could confer rapid and sustained protection against inhalation anthrax in mice in a single-dose regimen in the presence of preexisting adenovirus immunity. The potency of the vaccine was greatly enhanced when codons of the antigen gene were optimized to match the tRNA pool found in human cells. In addition, an adenovirus vector encoding lethal factor can confer partial protection against inhalation anthrax and might be coadministered with a protective antigen-based vaccine.

NASA Microgravity Materials Science Conference

NASA Technical Reports Server (NTRS)

Gillies, D. C. (Compiler); McCauley, D. E. (Compiler)

1999-01-01

The Microgravity Materials Science Conference was held July 14-16, 1998 at the Von Braun Center in Huntsville, AL. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Research Division at NASA Headquarters, and hosted by the NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications. It was the third NASA conference of this type in the microgravity materials science discipline. The microgravity science program sponsored approximately 125 investigations and 100 principal investigators in FY98, almost all of whom made oral or poster presentations at this conference. The conference's purpose was to inform the materials science community of research opportunities in reduced gravity in preparation for a NASA Research Announcement scheduled for release in late 1998 by the Microgravity Research Division at NASA Headquarters. The conference was aimed at materials science researchers from academia, industry, and government. A tour of the Marshall Space Flight Center microgravity research facilities was held on July 16, 1998. This volume is comprised of the research reports submitted by the principal investigators after the conference.

6th international conference on Mars polar science and exploration: Conference summary and five top questions

NASA Astrophysics Data System (ADS)

Smith, Isaac B.; Diniega, Serina; Beaty, David W.; Thorsteinsson, Thorsteinn; Becerra, Patricio; Bramson, Ali M.; Clifford, Stephen M.; Hvidberg, Christine S.; Portyankina, Ganna; Piqueux, Sylvain; Spiga, Aymeric; Titus, Timothy N.

2018-07-01

We provide a historical context of the International Conference on Mars Polar Science and Exploration and summarize the proceedings from the 6th iteration of this meeting. In particular, we identify five key Mars polar science questions based primarily on presentations and discussions at the conference and discuss the overlap between some of those questions. We briefly describe the seven scientific field trips that were offered at the conference, which greatly supplemented conference discussion of Mars polar processes and landforms. We end with suggestions for measurements, modeling, and laboratory and field work that were highlighted during conference discussion as necessary steps to address key knowledge gaps.

6th international conference on Mars polar science and exploration: Conference summary and five top questions

USGS Publications Warehouse

Smith, Isaac B.; Diniega, Serina; Beaty, David W.; Thorsteinsson, Thorsteinn; Becerra, Patricio; Bramson, Ali; Clifford, Stephen M.; Hvidberg, Christine S.; Portyankina, Ganna; Piqueux, Sylvain; Spiga, Aymeric; Titus, Timothy N.

2018-01-01

We provide a historical context of the International Conference on Mars Polar Science and Exploration and summarize the proceedings from the 6th iteration of this meeting. In particular, we identify five key Mars polar science questions based primarily on presentations and discussions at the conference and discuss the overlap between some of those questions. We briefly describe the seven scientific field trips that were offered at the conference, which greatly supplemented conference discussion of Mars polar processes and landforms. We end with suggestions for measurements, modeling, and laboratory and field work that were highlighted during conference discussion as necessary steps to address key knowledge gaps.

Conference Proceedings: (1) Research Conference on Racial Desegregation and Integration in Public Education; (2) Invitational Conference on Social Change and the Role of Behavioral Scientists.

ERIC Educational Resources Information Center

Gordon, Edmund W.; Green, Robert L.

This volume contains the proceedings of two conferences. One conference was concerned primarily with research on racial desegregation and integration in public education, and was highlighted by a paper by Irwin Katz, "Problems and Directions for Research in Public School Desegregation." The second conference focused on social change and the role…

Nanoparticle mediated micromotor motion

NASA Astrophysics Data System (ADS)

Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y.

2015-03-01

In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ~200 μm s-1. By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ~10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems.In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric

De-alloyed platinum nanoparticles

DOEpatents

Strasser, Peter [Houston, TX; Koh, Shirlaine [Houston, TX; Mani, Prasanna [Houston, TX; Ratndeep, Srivastava [Houston, TX

2011-08-09

A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

GE STEM Teacher's Conference

NASA Image and Video Library

2017-07-13

Teachers prepare to demonstrate the projects they built for the Rocketry Engineering Design Challenge during the 2017 GE Foundation High School STEM Integration Conference at the Center for Space Education at NASA's Kennedy Space Center. High school teachers from across the country took part in the week-long conference, which is designed to explore effective ways for teachers, schools and districts from across the country to integrate STEM throughout the curriculum. The conference is a partnership between GE Foundation and the National Science Teachers Association.

Synthetic lipid nanoparticles targeting steroid organs.

PubMed

Mérian, Juliette; Boisgard, Raphaël; Decleves, Xavier; Thezé, Benoît; Texier, Isabelle; Tavitian, Bertrand

2013-11-01

Lipidots are original nanoparticulate lipid delivery vectors for drugs and contrast agents made from materials generally regarded as safe. Here, we characterized the in vivo stability, biodistribution, and pharmacokinetics of lipidots. Lipidots 55 nm in diameter and coated with a phospholipid/poly(ethyleneglycol) surfactant shell were triply labeled with (3)H-cholesteryl-hexadecyl-ether, cholesteryl-(14)C-oleate, and the 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine infrared fluorescent dye and injected intravenously into immunocompetent Friend virus B-type mice. The pharmacokinetics and biodistribution of lipidots were analyzed quantitatively in serial samples of blood and tissue and with in vivo optical imaging and were refined by microscopic examination of selected target tissues. The plasmatic half-life of lipidots was approximately 30 min. Radioactive and fluorescent tracers displayed a similar nanoparticle-driven biodistribution, indicative of the lipidots' integrity during the first hours after injection. Lipidots distributed in the liver and, surprisingly, in the steroid-rich organs adrenals and ovaries, but not in the spleen. This tropism was confirmed at the microscopic level by histologic detection of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine. Nanoparticle loading with cholesterol derivatives increased accumulation in ovaries in a dose-dependent manner. This previously unreported distribution pattern is specific to lipidots and attributed to their nanometric size and composition, conferring on them a lipoproteinlike behavior. The affinity of lipidots for steroid hormone-rich areas is of interest to address drugs and contrast agents to lipoprotein-receptor-overexpressing cancer cells found in hormone-dependent tumors.

Conference for Undergraduate Women in Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bonnie Fleming

2009-04-01

The Yale Conference for Undergraduate Women in Physics was held on January 18th and 19th, 2008. The conference, targeted toward undergraduates in the Northeast, was a huge success. It was well attended by both a slate of impressive speakers including Janet Conrad, Mildred Dresselhaus, Elsa Garmire, Howard Georgi, Liz Rhodes, Meg Urry and Wendy Zhang, and many interested attendees. Talks were on current research, about issues for women in physics, and on the application process for graduate school. There was also a career panel, student talks, and a student poster session. The conference ran concurrently with the third annual conferencemore » at USC, as well as a first annual conference at the University of Michigan. Our purpose in creating this conference was to provide a supportive atmosphere for young physicists to connect with peers and with successful women in the field. We hope that from this conference, attendees have become confident and knowledgeable about applying to graduate school and be further inspired to pursue a career in physics. The following describes the conference program, participation and impact, logistics of running the conference and plans for the future.« less

2011 Superconductivity Centennial Conference - EUCAS-ISEC-ICMC

NASA Astrophysics Data System (ADS)

Rogalla, Horst

2012-11-01

In 2011 a Centennial Conference was organized in the "World Forum" Conference Center in Den Haag, the Netherlands, celebrating the discovery of Superconductivity by Heike Kamerlingh Onnes and his group 100 years ago in Leiden in the Netherlands. They found superconductivity in pure mercury after successfully liquefying helium for which Kamerlingh Onnes received a Nobel Prize in 1913. Since then superconductivity has been in the vivid focus of fundamental solid state physics, applied sciences and engineering in a very active community which already in 2005 came forward with the request to organize a Centennial Conference. Horst Rogalla and Dick Veldhuis from the University of Twente and Peter Kes from the University of Leiden took over the task to organize this conference in cooperation with three international conferences, the European Conference on Applied Superconductivity (EUCAS), the International Superconducting Electronics Conference (ISEC) and the International Cryogenic Materials Conference (ICMC). All three are biannual conferences with quite a long history in superconductivity, its applications and its materials.

Versatile Methodology to Encapsulate Gold Nanoparticles in PLGA Nanoparticles Obtained by Nano-Emulsion Templating.

PubMed

Fornaguera, Cristina; Feiner-Gracia, Natàlia; Dols-Perez, Aurora; García-Celma, Maria José; Solans, Conxita

2017-05-01

Gold nanoparticles have been proved useful for many biomedical applications, specifically, for their use as advanced imaging systems. However, they usually present problems related with stability and toxicity. In the present work, gold-nanoparticles have been encapsulated in polymeric nanoparticles using a novel methodology based on nano-emulsion templating. Firstly, gold nanoparticles have been transferred from water to ethyl acetate, a solvent classified as class III by the NIH guidelines (low toxic potential). Next, the formation of nano-emulsions loaded with gold nanoparticles has been performed using a low-energy, the phase inversion composition (PIC) emulsification method, followed by solvent evaporation giving rise to polymeric nanoparticles. Using this methodology, high concentrations of gold nanoparticles (>100 pM) have been encapsulated. Increasing gold nanoparticle concentration, nano-emulsion and nanoparticle sizes increase, resulting in a decrease on the stability. It is noteworthy that the designed nanoparticles did not produce cytotoxicity neither hemolysis at the required concentration. Therefore, it can be concluded that a novel and very versatile methodology has been developed for the production of polymeric nanoparticles loaded with gold nanoparticles. Graphical Abstract Schematic representation of AuNP-loaded polymeric nanoparticles preparation from nano-emulsion templating.

Improvement of the Trivalent Inactivated Flu Vaccine Using PapMV Nanoparticles

PubMed Central

Savard, Christian; Guérin, Annie; Drouin, Karine; Bolduc, Marilène; Laliberté-Gagné, Marie-Eve; Dumas, Marie-Christine; Majeau, Nathalie; Leclerc, Denis

2011-01-01

Commercial seasonal flu vaccines induce production of antibodies directed mostly towards hemaglutinin (HA). Because HA changes rapidly in the circulating virus, the protection remains partial. Several conserved viral proteins, e.g., nucleocapsid (NP) and matrix proteins (M1), are present in the vaccine, but are not immunogenic. To improve the protection provided by these vaccines, we used nanoparticles made of the coat protein of a plant virus (papaya mosaic virus; PapMV) as an adjuvant. Immunization of mice and ferrets with the adjuvanted formulation increased the magnitude and breadth of the humoral response to NP and to highly conserved regions of HA. They also triggered a cellular mediated immune response to NP and M1, and long-lasting protection in animals challenged with a heterosubtypic influenza strain (WSN/33). Thus, seasonal flu vaccine adjuvanted with PapMV nanoparticles can induce universal protection to influenza, which is a major advancement when facing a pandemic. PMID:21747909

Conference report: formulating better medicines for children: 4th European Paediatric Formulation Initiative conference.

PubMed

Walsh, Jennifer; Mills, Simon

2013-01-01

The fourth annual European Paediatric Formulation Initiative (EuPFI) conference on Formulating Better Medicines for Children was held on 19-20 September 2012 at the Institute of Molecular Genetics Congress Centre, Prague, Czech Republic. The 2-day conference concentrated on the latest advances, challenges and opportunities for developing medicinal products and administration devices for pediatric use, both from European and US perspectives. It was aimed specifically at providing exposure to emerging practical applications, and for illustrating remedies utilized by pediatric drug-development teams to overcome hurdles faced in developing medicines for pediatric patients. The conference format included plenary talks, focus sessions on each of the EuPFI work streams (extemporaneous preparations, excipients, pediatric administration devices, taste masking and taste assessment, age-appropriate formulations), case studies, soapbox sessions and a parallel poster display. This conference report summarizes the keynote lectures and also gives a flavor of other presentations and posters from the conference.

Experimental and theoretical investigation of intratumoral nanoparticle distribution to enhance magnetic nanoparticle hyperthermia

NASA Astrophysics Data System (ADS)

Attaluri, Anilchandra

Magnetic nanoparticles have gained prominence in recent years for use in clinical applications such as imaging, drug delivery, and hyperthermia. Magnetic nanoparticle hyperthermia is a minimally invasive and effective approach for confined heating in tumors with little collateral damage. One of the major problems in the field of magnetic nanoparticle hyperthermia is irregular heat distribution in tumors which caused repeatable heat distribution quite impossible. This causes under dosage in tumor area and overheating in normal tissue. In this study, we develop a unified approach to understand magnetic nanoparticle distribution and temperature elevations in gel and tumors. A microCT imaging system is first used to visualize and quantify nanoparticle distribution in both tumors and tissue equivalent phantom gels. The microCT based nanoparticle concentration is related to specific absorption rate (SAR) of the nanoparticles and is confirmed by heat distribution experiments in tissue equivalent phantom gels. An optimal infusion protocol is identified to generate controllable and repeatable nanoparticle distribution in tumors. In vivo animal experiments are performed to measure intratumoral temperature elevations in PC3 xenograft tumors implanted in mice during magnetic nanoparticle hyperthermia. The effect of nanofluid injection parameters on the resulted temperature distribution is studied. It shows that the tumor temperatures can be elevated above 50°C using very small amounts of ferrofluid with a relatively low magnetic field. Slower ferrofluid infusion rates result in smaller nanoparticle distribution volumes in the tumors, however, it gives the much required controllability and repeatability when compared to the higher infusion rates. More nanoparticles occupy a smaller volume in the vicinity of the injection site with slower infusion rates, causing higher temperature elevations in the tumors. Based on the microCT imaging analyses of nanoparticles in tumors, a mass

Cellular Binding of Anionic Nanoparticles is Inhibited by Serum Proteins Independent of Nanoparticle Composition.

PubMed

Fleischer, Candace C; Kumar, Umesh; Payne, Christine K

2013-09-01

Nanoparticles used in biological applications encounter a complex mixture of extracellular proteins. Adsorption of these proteins on the nanoparticle surface results in the formation of a "protein corona," which can dominate the interaction of the nanoparticle with the cellular environment. The goal of this research was to determine how nanoparticle composition and surface modification affect the cellular binding of protein-nanoparticle complexes. We examined the cellular binding of a collection of commonly used anionic nanoparticles: quantum dots, colloidal gold nanoparticles, and low-density lipoprotein particles, in the presence and absence of extracellular proteins. These experiments have the advantage of comparing different nanoparticles under identical conditions. Using a combination of fluorescence and dark field microscopy, flow cytometry, and spectroscopy, we find that cellular binding of these anionic nanoparticles is inhibited by serum proteins independent of nanoparticle composition or surface modification. We expect these results will aid in the design of nanoparticles for in vivo applications.

Polymer film-nanoparticle composites as new multimodality, non-migrating breast biopsy markers.

PubMed

Kaplan, Jonah A; Grinstaff, Mark W; Bloch, B Nicolas

2016-03-01

To develop a breast biopsy marker that resists fast and slow migration and has permanent visibility under commonly used imaging modalities. A polymer-nanoparticle composite film was prepared by embedding superparamagnetic iron oxide nanoparticles and a superelastic Nitinol wire within a flexible polyethylene matrix. MRI, mammography, and ultrasound were used to visualize the marker in agar, ex vivo chicken breast, bovine liver, brisket, and biopsy training phantoms. Fast migration caused by the "accordion effect" was quantified after simulated stereotactic, vacuum-assisted core biopsy/marker placement, and centrifugation was used to simulate accelerated long-term (i.e., slow) migration in ex vivo bovine tissue phantoms. Clear marker visualization under MRI, mammography, and ultrasound was observed. After deployment, the marker partially unfolds to give a geometrically constrained structure preventing fast and slow migration. The marker can be deployed through an 11G introducer without fast migration occurring, and shows substantially less slow migration than conventional markers. The polymer-nanoparticle composite biopsy marker is clearly visible on all clinical imaging modalities and does not show substantial migration, which ensures multimodal assessment of the correct spatial information of the biopsy site, allowing for more accurate diagnosis and treatment planning and improved breast cancer patient care. Polymer-nanoparticle composite biopsy markers are visualized using ultrasound, MRI, and mammography. Embedded iron oxide nanoparticles provide tuneable contrast for MRI visualization. Permanent ultrasound visibility is achieved with a non-biodegradable polymer having a distinct ultrasound signal. Flexible polymer-based biopsy markers undergo shape change upon deployment to minimize migration. Non-migrating multimodal markers will help improve accuracy of pre/post-treatment planning studies.

PREFACE: XXI Fluid Mechanics Conference

NASA Astrophysics Data System (ADS)

Szmyd, Janusz S.; Fornalik-Wajs, Elzbieta; Jaszczur, Marek

2014-08-01

This Conference Volume contains the papers presented at the 21st Fluid Mechanics Conference (XXI FMC) held at AGH - University of Science and Technology in Krakow, Poland, 15-18 June 2014, and accepted for Proceedings published in the Journal of Physics: Conference Series. The Fluid Mechanics Conferences have been taking place every two years since 1974, a total of forty years. The 21st Fluid Mechanics Conference (XXI FMC) is being organized under the auspices of the Polish Academy of Sciences, Committee of Mechanics. The goal of this conference is to provide a forum for the exposure and exchange of ideas, methods and results in fluid mechanics. Conference topics include, but are not limited to Aerodynamics, Atmospheric Science, Bio-Fluids, Combustion and Reacting Flows, Computational Fluid Dynamics, Experimental Fluid Mechanics, Flow Machinery, General Fluid Dynamics, Hydromechanics, Heat and Fluid Flow, Measurement Techniques, Micro- and Nano- Flow, Multi-Phase Flow, Non-Newtonian Fluids, Rotating and Stratified Flows, Turbulence. Within the general subjects of this conference, the Professor Janusz W. Elsner Competition for the best fluid mechanics paper presented during the Conference is organized. Authors holding a M.Sc. or a Ph.D. degree and who are not older than 35 years of age may enter the Competition. Authors with a Ph.D. degree must present individual papers; authors with a M.Sc. degree may present papers with their supervisor as coauthor, including original results of experimental, numerical or analytic research. Six state-of-the-art keynote papers were delivered by world leading experts. All contributed papers were peer reviewed. Recommendations were received from the International Scientific Committee, reviewers and the advisory board. Accordingly, of the 163 eligible extended abstracts submitted, after a review process by the International Scientific Committee, 137 papers were selected for presentation at the 21st Fluid Mechanics Conference, 68

77 FR 46374 - National Poultry Improvement Plan; General Conference Committee Meeting and 41st Biennial Conference

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-03

...] National Poultry Improvement Plan; General Conference Committee Meeting and 41st Biennial Conference AGENCY... notice of a meeting of the General Conference Committee of the National Poultry Improvement Plan (NPIP... CONTACT: Dr. C. Stephen Roney, Senior Coordinator, National Poultry Improvement Plan, VS, APHIS, 1506...

The Conference Facilitator Model: Improving the Value of Conference Attendance for Attendees and the Organization.

PubMed

Nebrig, Dawn; Munafo, Jennifer; Goddard, Julie; Tierney, Carol

2015-09-01

Healthcare leaders face a multitude of priorities demanding their attention and resources, from patient, employee safety and hospital-acquired conditions to predicting future revenue in the context of healthcare reform. Assessing value requires balancing outcomes and experience with cost. How does allocating funds for professional nursing conferences measure up? What is a valid return on investment when we send staff nurses to professional conferences, specifically the annual Magnet® conference? The following article describes how Cincinnati Children's Hospital Medical Center answered these questions and redefined the expectations for conference attendees while enhancing the experience and the reportable outcomes for practice and the organization.

Hydrophobic drug-triggered self-assembly of nanoparticles from silk-elastin-like protein polymers for drug delivery.

PubMed

Xia, Xiao-Xia; Wang, Ming; Lin, Yinan; Xu, Qiaobing; Kaplan, David L

2014-03-10

Silk-elastin-like protein polymers (SELPs) combine the mechanical and biological properties of silk and elastin. These properties have led to the development of various SELP-based materials for drug delivery. However, SELPs have rarely been developed into nanoparticles, partially due to the complicated fabrication procedures, nor assessed for potential as an anticancer drug delivery system. We have recently constructed a series of SELPs (SE8Y, S2E8Y, and S4E8Y) with various ratios of silk to elastin blocks and described their capacity to form micellar-like nanoparticles upon thermal triggering. In this study, we demonstrate that doxorubicin, a hydrophobic antitumor drug, can efficiently trigger the self-assembly of SE8Y (SELPs with silk to elastin ratio of 1:8) into uniform micellar-like nanoparticles. The drug can be loaded in the SE8Y nanoparticles with an efficiency around 6.5% (65 ng doxorubicin/μg SE8Y), S2E8Y with 6%, and S4E8Y with 4%, respectively. In vitro studies with HeLa cell lines demonstrate that the protein polymers are not cytotoxic (IC50 > 200 μg/mL), while the doxorubicin-loaded SE8Y nanoparticles showed a 1.8-fold higher cytotoxicity than the free drug. Confocal laser scanning microscopy (CLSM) and flow cytometry indicate significant uptake of the SE8Y nanoparticles by the cells and suggest internalization of the nanoparticles through endocytosis. This study provides an all-aqueous, facile method to prepare nanoscale, drug-loaded SELPs packages with potential for tumor cell treatments.

Synthesis and Characterization of BSA Conjugated Silver Nanoparticles (Ag/BSA Nanoparticles) and Evaluation of Biological Properties of Ag/BSA Nanoparticles and Ag/BSA Nanoparticles Loaded Poly(hydroxy butyrate valerate) PHBV Films

NASA Astrophysics Data System (ADS)

Ambaye, Almaz

Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa are the etiological agents of several infectious diseases. Antibiotic resistance by these three microbes has emerged as a prevalent problem due in part to the misuse of existing antibiotics and the lack of novel antibiotics. Nanoparticles have emerged as an alternative antibacterial agents to conventional antibiotics owing to their high surface area to volume ratio and their unique chemical and physical properties. Among the nanoparticles, silver nanoparticles have gained increasing attention because silver nanoparticles exhibit antibacterial activity against a range of gram positive and gram negative bacteria. Nanoparticles of well-defined chemistry and morphology can be used in broad biomedical applications, especially in bone tissue engineering applications, where bone infection by bacteria can be acute and lethal. It is commonly noted in the literature that the activity of nanoparticles against microorganisms is dependent upon the size and concentration of the nanoparticles as well as the chemistry of stabilizing agent. To the best of our knowledge, a comprehensive study that evaluates the antibacterial activity of well characterized silver nanoparticles in particular Bovine Serum Albumin (BSA) stabilized against S. aureus and E. coli and cytotoxicity level of BSA stabilized silver nanoparticles towards osteoblast cells (MC3T3-E1) is currently lacking. Therefore, the primary objective of this study was to characterize protein conjugated silver nanoparticles prepared by chemical reduction of AgNO3 and BSA mixture. The formation of Ag/BSA nanoparticles was studied by UV-Vis spectroscopy. The molar ratio of silver to BSA in the Ag/BSA nanoparticles was established to be 27+/- 3: 1, based on Thermogravimetric Analysis and Atomic Absorption Spectroscopy. Based on atomic force microscopy, dynamic light scattering,and transmission electron microscopy(TEM) measurements, the particle size (diameter) of

76 FR 57746 - Conference on the International Conference on Harmonisation Q10 Pharmaceutical Quality System: A...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-16

... ``Pharmaceutical Quality System (ICH Q10) Conference: A Practical Approach to Effective Life- Cycle Implementation... Pharmaceutical Quality System across the product life cycle according to the ICH Q10 model. These companies are...] Conference on the International Conference on Harmonisation Q10 Pharmaceutical Quality System: A Practical...

NASA Microgravity Materials Science Conference

NASA Technical Reports Server (NTRS)

Szofran, Frank R. (Compiler); McCauley, D. (Compiler); Walker, C. (Compiler)

1996-01-01

The Microgravity Materials Science Conference was held June 10-11, 1996 at the Von Braun Civic Center in Huntsville, AL. It was organized by the Microgravity Materials Science Discipline Working Group, sponsored by the Microgravity Science and Applications Division at NASA Headquarters, and hosted by the NASA Marshall Space Flight Center and the Alliance for Microgravity Materials Science and Applications (AMMSA). It was the second NASA conference of this type in the microgravity materials science discipline. The microgravity science program sponsored approximately 80 investigations and 69 principal investigators in FY96, all of whom made oral or poster presentations at this conference. The conference's purpose was to inform the materials science community of research opportunities in reduced gravity in preparation for a NASA Research Announcement (NRA) scheduled for release in late 1996 by the Microgravity Science and Applications Division at NASA Headquarters. The conference was aimed at materials science researchers from academia, industry, and government. A tour of the MSFC microgravity research facilities was held on June 12, 1996. This volume is comprised of the research reports submitted by the principal investigators after the conference and presentations made by various NASA microgravity science managers.

Aviation Safety/Automation Program Conference

NASA Technical Reports Server (NTRS)

Morello, Samuel A. (Compiler)

1990-01-01

The Aviation Safety/Automation Program Conference - 1989 was sponsored by the NASA Langley Research Center on 11 to 12 October 1989. The conference, held at the Sheraton Beach Inn and Conference Center, Virginia Beach, Virginia, was chaired by Samuel A. Morello. The primary objective of the conference was to ensure effective communication and technology transfer by providing a forum for technical interchange of current operational problems and program results to date. The Aviation Safety/Automation Program has as its primary goal to improve the safety of the national airspace system through the development and integration of human-centered automation technologies for aircraft crews and air traffic controllers.

Rare Earth Oxide Fluoride Nanoparticles And Hydrothermal Method For Forming Nanoparticles

DOEpatents

Fulton, John L.; Hoffmann, Markus M.

2003-12-23

A hydrothermal method for forming nanoparticles of a rare earth element, oxygen and fluorine has been discovered. Nanoparticles comprising a rare earth element, oxygen and fluorine are also described. These nanoparticles can exhibit excellent refractory properties as well as remarkable stability in hydrothermal conditions. The nanoparticles can exhibit excellent properties for numerous applications including fiber reinforcement of ceramic composites, catalyst supports, and corrosion resistant coatings for high-temperature aqueous solutions.

Rare earth oxide fluoride nanoparticles and hydrothermal method for forming nanoparticles

DOEpatents

Fulton, John L [Richland, WA; Hoffmann, Markus M [Richland, WA

2001-11-13

A hydrothermal method for forming nanoparticles of a rare earth element, oxygen and fluorine has been discovered. Nanoparticles comprising a rare earth element, oxygen and fluorine are also described. These nanoparticles can exhibit excellent refractory properties as well as remarkable stability in hydrothermal conditions. The nanoparticles can exhibit excellent properties for numerous applications including fiber reinforcement of ceramic composites, catalyst supports, and corrosion resistant coatings for high-temperature aqueous solutions.

Experts' understanding of partial derivatives using the partial derivative machine

NASA Astrophysics Data System (ADS)

Roundy, David; Weber, Eric; Dray, Tevian; Bajracharya, Rabindra R.; Dorko, Allison; Smith, Emily M.; Manogue, Corinne A.

2015-12-01

[This paper is part of the Focused Collection on Upper Division Physics Courses.] Partial derivatives are used in a variety of different ways within physics. Thermodynamics, in particular, uses partial derivatives in ways that students often find especially confusing. We are at the beginning of a study of the teaching of partial derivatives, with a goal of better aligning the teaching of multivariable calculus with the needs of students in STEM disciplines. In this paper, we report on an initial study of expert understanding of partial derivatives across three disciplines: physics, engineering, and mathematics. We report on the central research question of how disciplinary experts understand partial derivatives, and how their concept images of partial derivatives differ, with a focus on experimentally measured quantities. Using the partial derivative machine (PDM), we probed expert understanding of partial derivatives in an experimental context without a known functional form. In particular, we investigated which representations were cued by the experts' interactions with the PDM. Whereas the physicists and engineers were quick to use measurements to find a numeric approximation for a derivative, the mathematicians repeatedly returned to speculation as to the functional form; although they were comfortable drawing qualitative conclusions about the system from measurements, they were reluctant to approximate the derivative through measurement. On a theoretical front, we found ways in which existing frameworks for the concept of derivative could be expanded to include numerical approximation.

Size and shape effects on diffusion and absorption of colloidal particles near a partially absorbing sphere: implications for uptake of nanoparticles in animal cells.

PubMed

Shi, Wendong; Wang, Jizeng; Fan, Xiaojun; Gao, Huajian

2008-12-01

A mechanics model describing how a cell membrane with diffusive mobile receptors wraps around a ligand-coated cylindrical or spherical particle has been recently developed to model the role of particle size in receptor-mediated endocytosis. The results show that particles in the size range of tens to hundreds of nanometers can enter cells even in the absence of clathrin or caveolin coats. Here we report further progress on modeling the effects of size and shape in diffusion, interaction, and absorption of finite-sized colloidal particles near a partially absorbing sphere. Our analysis indicates that, from the diffusion and interaction point of view, there exists an optimal hydrodynamic size of particles, typically in the nanometer regime, for the maximum rate of particle absorption. Such optimal size arises as a result of balance between the diffusion constant of the particles and the interaction energy between the particles and the absorbing sphere relative to the thermal energy. Particles with a smaller hydrodynamic radius have larger diffusion constant but weaker interaction with the sphere while larger particles have smaller diffusion constant but stronger interaction with the sphere. Since the hydrodynamic radius is also determined by the particle shape, an optimal hydrodynamic radius implies an optimal size as well as an optimal aspect ratio for a nonspherical particle. These results show broad agreement with experimental observations and may have general implications on interaction between nanoparticles and animal cells.

Size and shape effects on diffusion and absorption of colloidal particles near a partially absorbing sphere: Implications for uptake of nanoparticles in animal cells

NASA Astrophysics Data System (ADS)

Shi, Wendong; Wang, Jizeng; Fan, Xiaojun; Gao, Huajian

2008-12-01

A mechanics model describing how a cell membrane with diffusive mobile receptors wraps around a ligand-coated cylindrical or spherical particle has been recently developed to model the role of particle size in receptor-mediated endocytosis. The results show that particles in the size range of tens to hundreds of nanometers can enter cells even in the absence of clathrin or caveolin coats. Here we report further progress on modeling the effects of size and shape in diffusion, interaction, and absorption of finite-sized colloidal particles near a partially absorbing sphere. Our analysis indicates that, from the diffusion and interaction point of view, there exists an optimal hydrodynamic size of particles, typically in the nanometer regime, for the maximum rate of particle absorption. Such optimal size arises as a result of balance between the diffusion constant of the particles and the interaction energy between the particles and the absorbing sphere relative to the thermal energy. Particles with a smaller hydrodynamic radius have larger diffusion constant but weaker interaction with the sphere while larger particles have smaller diffusion constant but stronger interaction with the sphere. Since the hydrodynamic radius is also determined by the particle shape, an optimal hydrodynamic radius implies an optimal size as well as an optimal aspect ratio for a nonspherical particle. These results show broad agreement with experimental observations and may have general implications on interaction between nanoparticles and animal cells.

Effect of silica nanoparticles on polyurethane foaming process and foam properties

NASA Astrophysics Data System (ADS)

Francés, A. B.; Navarro Bañón, M. V.

2014-08-01

Flexible polyurethane foams (FPUF) are commonly used as cushioning material in upholstered products made on several industrial sectors: furniture, automotive seating, bedding, etc. Polyurethane is a high molecular weight polymer based on the reaction between a hydroxyl group (polyol) and isocyanate. The density, flowability, compressive, tensile or shearing strength, the thermal and dimensional stability, combustibility, and other properties can be adjusted by the addition of several additives. Nanomaterials offer a wide range of possibilities to obtain nanocomposites with specific properties. The combination of FPUF with silica nanoparticles could develop nanocomposite materials with unique properties: improved mechanical and thermal properties, gas permeability, and fire retardancy. However, as silica particles are at least partially surface-terminated with Si-OH groups, it was suspected that the silica could interfere in the reaction of poyurethane formation.The objective of this study was to investigate the enhancement of thermal and mechanical properties of FPUF by the incorporation of different types of silica and determining the influence thereof during the foaming process. Flexible polyurethane foams with different loading mass fraction of silica nanoparticles (0-1% wt) and different types of silica (non treated and modified silica) were synthesized. PU/SiO2 nanocomposites were characterized by FTIR spectroscopy, TGA, and measurements of apparent density, resilience and determination of compression set. Addition of silica nanoparticles influences negatively in the density and compression set of the foams. However, resilience and thermal stability of the foams are improved. Silica nanoparticles do not affect to the chemical structure of the foams although they interfere in the blowing reaction.

Modulating Excitonic Recombination Effects through One-Step Synthesis of Perovskite Nanoparticles for Light-Emitting Diodes.

PubMed

Kulkarni, Sneha A; Muduli, Subas; Xing, Guichuan; Yantara, Natalia; Li, Mingjie; Chen, Shi; Sum, Tze Chien; Mathews, Nripan; White, Tim J; Mhaisalkar, Subodh G

2017-10-09

The primary advantages of halide perovskites for light-emitting diodes (LEDs) are solution processability, direct band gap, good charge-carrier diffusion lengths, low trap density, and reasonable carrier mobility. The luminescence in 3 D halide perovskite thin films originates from free electron-hole bimolecular recombination. However, the slow bimolecular recombination rate is a fundamental performance limitation. Perovskite nanoparticles could result in improved performance but processability and cumbersome synthetic procedures remain challenges. Herein, these constraints are overcome by tailoring the 3 D perovskite as a near monodisperse nanoparticle film prepared through a one-step in situ deposition method. Replacing methyl ammonium bromide (CH 3 NH 3 Br, MABr) partially by octyl ammonium bromide [CH 3 (CH 2 ) 7 NH 3 Br, OABr] in defined mole ratios in the perovskite precursor proved crucial for the nanoparticle formation. Films consisting of the in situ formed nanoparticles displayed signatures associated with excitonic recombination, rather than that of bimolecular recombination associated with 3 D perovskites. This transition was accompanied by enhanced photoluminescence quantum yield (PLQY≈20.5 % vs. 3.40 %). Perovskite LEDs fabricated from the nanoparticle films exhibit a one order of magnitude improvement in current efficiency and doubling in luminance efficiency. The material processing systematics derived from this study provides the means to control perovskite morphologies through the selection and mixing of appropriate additives. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoparticle mediated micromotor motion.

PubMed

Liu, Mei; Liu, Limei; Gao, Wenlong; Su, Miaoda; Ge, Ya; Shi, Lili; Zhang, Hui; Dong, Bin; Li, Christopher Y

2015-03-21

In this paper, we report the utilization of nanoparticles to mediate the motion of a polymer single crystal catalytic micromotor. Micromotors have been fabricated by directly self-assembling functional nanoparticles (platinum and iron oxide nanoparticles) onto one or both sides of two-dimensional polymer single crystals. We show that the moving velocity of these micromotors in fluids can be readily tuned by controlling the nanoparticles' surface wettability and catalytic activity. A 3 times velocity increase has been achieved for a hydrophobic micromotor as opposed to the hydrophilic ones. Furthermore, we demonstrate that the catalytic activity of platinum nanoparticles inside the micromotor can be enhanced by their synergetic interactions with iron oxide nanoparticles and an electric field. Both strategies lead to dramatically increased moving velocities, with the highest value reaching ∼200 μm s(-1). By decreasing the nanoparticles' surface wettability and increasing their catalytic activity, a maximum of a ∼10-fold increase in the moving speed of the nanoparticle based micromotor can be achieved. Our results demonstrate the advantages of using nanoparticles in micromotor systems.

PREFACE: The Irago Conference 2012

NASA Astrophysics Data System (ADS)

Sandhu, Adarsh; Okada, Hiroshi

2013-04-01

The Irago Conference 2012 - 360 degree outlook on critical scientific and technological challenges for a sustainable society Organized by the Electronics-Inspired Interdisciplinary Research Institute (EIIRIS) at Toyohashi University of Technology, the Irago Conference, held recently (15-16 November) in Aichi, Japan, aimed to enhance mutual understanding between scientists, engineers and policymakers. Over 180 participants tackled topics ranging from energy and natural resources to public health and disaster prevention. The 360-degree outlook of the conference impressed speakers and guests. ''This conference has been extremely informative,'' noted Robert Gellar from the University of Tokyo. ''A unique conference with experts from a range of backgrounds,'' agreed Uracha Ruktanonchai from the National Nanotechnology Center (NANOTEC) in Thailand. Similarly, G P Li, professor of electrical engineering and computer science at the University of California Irvine commented that he had been ''able to think the unthinkable'' as a range of topics came together. The conference was streamed live on Ustream to ensure that researchers from across the world could benefit from thought-provoking presentations examining global issues such as energy, disaster mitigation and nanotechnology. ''This was wonderful,'' said Oussama Khatib from Stanford University, ''A good recipe of speakers from such a range of backgrounds.'' Manuscripts submitted to the organizers were peer-reviewed, and the papers in this proceedings were accepted for Journal of Physics: Conference Series. In addition to the formal speaker programme, graduate-student sessions provided a platform for graduate students to describe their latest findings as oral presentations. A series of excursions to relevant locations, such as the Tahara megasolar region under construction and a local car-manufacturing factory, gave participants the opportunity to further consider practical applications of their research in industry

7 CFR 47.14 - Prehearing conferences.

Code of Federal Regulations, 2012 CFR

2012-01-01

... determines that conducting the conference by audio-visual telecommunication: (i) Is necessary to prevent.... If the examiner determines that a conference conducted by audio-visual telecommunication would... correspondence, the conference shall be conducted by audio-visual telecommunication unless the examiner...

Thermodynamic changes in mechanochemically synthesized magnesium hydride nanoparticles.

PubMed

Paskevicius, Mark; Sheppard, Drew A; Buckley, Craig E

2010-04-14

The thermodynamic properties of magnesium hydride nanoparticles have been investigated by hydrogen decomposition pressure measurements using the Sieverts technique. A mechanochemical method was used to synthesize MgH(2) nanoparticles (down to approximately 7 nm in size) embedded in a LiCl salt matrix. In comparison to bulk MgH(2), the mechanochemically produced MgH(2) with the smallest particle size showed a small but measurable decrease in the decomposition reaction enthalpy (DeltaH decrease of 2.84 kJ/mol H(2) from DeltaH(bulk) = 74.06 +/- 0.42 kJ/mol H(2) to DeltaH(nano) = 71.22 +/- 0.49 kJ/mol H(2)). The reduction in DeltaH matches theoretical predictions and was also coupled with a similar reduction in reaction entropy (DeltaS decrease of 3.8 J/mol H(2)/K from DeltaS(bulk) = 133.4 +/- 0.7 J/mol H(2)/K to DeltaS(nano) = 129.6 +/- 0.8 J/mol H(2)/K). The thermodynamic changes in the MgH(2) nanoparticle system correspond to a drop in the 1 bar hydrogen equilibrium temperature (T(1 bar)) by approximately 6 degrees C to 276.2 +/- 2.4 degrees C in contrast to the bulk MgH(2) system at 281.8 +/- 2.2 degrees C. The reduction in the desorption temperature is less than that expected from theoretical studies due to the decrease in DeltaS that acts to partially counteract the effect from the change in DeltaH.

Nanoparticles for Biomedical Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nune, Satish K.; Gunda, Padmaja; Thallapally, Praveen K.

2009-11-01

Background: Synthetic nanoparticles are emerging as versatile tools in biomedical applications, particularly in the area of biomedical imaging. Nanoparticles 1 to 100 nm in diameter possess dimensions comparable to biological functional units. Diverse surface chemistries, unique magnetic properties, tunable absorption and emission properties, and recent advances in the synthesis and engineering of various nanoparticles suggest their potential as probes for early detection of diseases such as cancer. Surface functionalization has further expanded the potential of nanoparticles as probes for molecular imaging. Objective: To summarize emerging research of nanoparticles for biomedical imaging with increased selectivity and reduced non-specific uptake with increasedmore » spatial resolution containing stabilizers conjugated with targeting ligands. Methods: This review summarizes recent technological advances in the synthesis of various nanoparticle probes, and surveys methods to improve the targeting of nanoparticles for their applications in biomedical imaging. Conclusion: Structural design of nanomaterials for biomedical imaging continues to expand and diversify. Synthetic methods have aimed to control the size and surface characteristics of nanoparticles to control distribution, half-life and elimination. Although molecular imaging applications using nanoparticles are advancing into clinical applications, challenges such as storage stability and long-term toxicology should continue to be addressed. Keywords: nanoparticle synthesis, surface modification, targeting, molecular imaging, and biomedical imaging.« less

Experts' Understanding of Partial Derivatives Using the Partial Derivative Machine

ERIC Educational Resources Information Center

Roundy, David; Weber, Eric; Dray, Tevian; Bajracharya, Rabindra R.; Dorko, Allison; Smith, Emily M.; Manogue, Corinne A.

2015-01-01

Partial derivatives are used in a variety of different ways within physics. Thermodynamics, in particular, uses partial derivatives in ways that students often find especially confusing. We are at the beginning of a study of the teaching of partial derivatives, with a goal of better aligning the teaching of multivariable calculus with the needs of…

2017 Gordon Conference on Superconductivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chubukov, Andrey

The DOE award was for a 2017 Gordon Research conference on Superconductivity (GRC). The objective of GRC is to interchange the information about the latest theoretical and experimental developments in the area of superconductivity and to select most perspective directions for future research in this area.The goal of the Gordon Conference on Superconductivity is to present and discuss the latest results in the field of modern superconductivity, discuss new ideas and new directions of research in the area. It is a long-standing tradition of the Gordon conference on Superconductivity that the vast majority of participants are junior scientists. Funding formore » the conference would primarily be used to support junior researchers, particularly from under-represented groups. We had more 10 female speakers, some of them junior researchers, and some funding was used to support these speakers. The conference was held together with Gordon Research Seminar on Superconductivity, where almost all speakers and participants were junior scientists.« less

Hybrid metal-organic conductive network with plasmonic nanoparticles and fluorene (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fontana, Laura; Fratoddi, Ilaria; Matassa, Roberto; Familiari, Giuseppe; Venditti, Iole; Batocchio, Chiara; Magnano, Elena; Nappini, Silvia; Leahu, Grigore; Belardini, Alessandro; Li Voti, Roberto; Sibilia, Concita

2017-05-01

For the development of new generation portable electronic devices, the realization of thin and flexible electrodes have a crucial role. Conductive organic systems can address this issue in different ways. Indeed, conductance in organic molecules were studied in different papers starting from seminal papers in last 70's [1] up to recent ones [2]. Among organic species, conduction and electronic characteristics of Fluorene derivatives were studied in different configurations [3,4]. Unfortunately, the conductance of organic materials is limited by charge transport mechanism [5]. Hybrid system with organic conductive compounds covalently linked with metal centres can lead to enhanced conductivity [6]. Here we synthesized gold and silver nanoparticles (AuNPs and AgNPs) stabilized with a fluorene thiolate derivative, namely 9,9-Didodecyl-2,7-bis(acetylthio)fluorene (FL). In the synthesis process the metal nanoparticles (MNPs) size results to be around 5 nm in diameter [7]. When deposited on a planar substrate, the hybrid compound form a regular network of MNPs separated each other by fluorene spacers covalently linked by thiol groups [8]. We deposited the network on substrate with two interdigitated electrodes in order to measure conductive properties (I-V characteristics). In I-V measurements it results to be that AgNPs based network is 200 times more conductive than AuNPs one. Selective oxidation of AgNPs network close to positive electrodes gives rise to a Schottky diode behavior in the I-V characteristic that could find potential applications in nano-electronics devices. The fluorescence and extinction spectra of FL-AgNPs and FL-AuNPs where characterised. References [1] C. K. Chiang, C. R. Fincher, Jr., Y. W. Park, A. J. Heeger, H. Shirakawa, E. J. Louis, S. C. Gau, and Alan G. MacDiarmid, Phys. Rev. Lett. 39, 1098 (1977). [2] Hylke B. Akkerman, Paul W. M. Blom, Dago M. de Leeuw and Bert de Boer, Nature 441, 69 (2006). [3] Rajendra Prasad Kalakodimi, Aletha M. Nowak

Final report. (This is a conference support, no publications were delivered)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, F.; Hill, R.; Zohar, Y.

2004-05-01

Fifth International Symposium on the Biology of Actinomyces, December, 2003, Australia; (2) Ocean Research Conference Hawaii, February 16-20, 2004; (3) World Aquaculture Conference Hawaii, March 1-5, 2004; and (4) The 10th International Symposium of Microbial Ecology, Cancun, Mexico, August, 2004. The remaining funds will be used to assist partial traveling cost for the graduate students who participate and present in the meetings mentioned above. The amount of support and number of awardees will be decided by PIs Drs. Feng Chen, Russell Hill, and Yonathan Zohar. The original grant (DE-FG02-03ER63563) ended by December 31, 2003, Dr. Palmisano suggested to us to contact DOE operations at Chicago for a no cost extension. Please let us know if more information is needed.« less

Counterion effects in protein nanoparticle electrostatic binding: a theoretical study.

PubMed

Ghosh, Goutam

2015-04-01

Effects of counterions on the folding conformation of proteins, bound electrostatically on the surface of charge-ligand functionalized nanoparticles, have been investigated based on the protein folding energy calculation. The folding energy of a protein has been taken as a sum of the short range interaction energies, like, the van der Waals attraction and the hydrogen bond energies, and the long range coulomb interaction energy. On electrostatic binding, counterions associated with surface ligands of nanoparticles diffuse into bound proteins through the medium of dispersion. As a result, bound proteins partially unfold, as observed in circular dichroism experiments, which has been realized using the "charge-dipole" and the "charge-induced dipole" interactions of counterions with polar and non-polar residues, respectively. The effect of counterions solvation in the dispersing medium, e.g., water, which causes water molecules to polarize around the counterions, has also been considered. The folding energy of bound proteins has been seen to decrease proportionally with the increasing number of diffusion of counterions and their polarizability. Copyright © 2015 Elsevier B.V. All rights reserved.

Catalytic performance of M@Ni (M = Fe, Ru, Ir) core-shell nanoparticles towards ammonia decomposition for CO x -free hydrogen production

NASA Astrophysics Data System (ADS)

Chen, Xin; Zhou, Junwei; Chen, Shuangjing; Zhang, Hui

2018-06-01

To reduce the use of precious metals and maintain the catalytic activity for NH3 decomposition reaction, it is an effective way to construct bimetallic nanoparticles with special structures. In this paper, by using density functional theory methods, we investigated NH3 decomposition reaction on three types of core-shell nanoparticles M@Ni (M = Fe, Ru, Ir) with 13 core M atoms and 42 shell Ni atoms. The size of these three particles is about 1 nm. Benefit from alloying with Ru in this nanocluster, Ru@Ni core-shell nanoparticles exhibit catalytic activity comparable to that of single metal Ru, based on the analysis of the adsorption energy and potential energy diagram of NH3 decomposition, as well as N2 desorption processes. However, as for Fe@Ni and Ir@Ni core-shell nanoparticles, their catalytic activities are still unsatisfactory compared to the active metal Ru. In addition, in order to further explain the synergistic effect of bimetallic core-shell nanoparticles, the partial density of states were also calculated. The results show that d-band electrons provided by the core metal are the main factors affecting the entire catalytic process.

An Adenovirus-Vectored Nasal Vaccine Confers Rapid and Sustained Protection against Anthrax in a Single-Dose Regimen

PubMed Central

Jex, Edward; Feng, Tsungwei; Sivko, Gloria S.; Baillie, Leslie W.; Goldman, Stanley; Van Kampen, Kent R.; Tang, De-chu C.

2013-01-01

Bacillus anthracis is the causative agent of anthrax, and its spores have been developed into lethal bioweapons. To mitigate an onslaught from airborne anthrax spores that are maliciously disseminated, it is of paramount importance to develop a rapid-response anthrax vaccine that can be mass administered by nonmedical personnel during a crisis. We report here that intranasal instillation of a nonreplicating adenovirus vector encoding B. anthracis protective antigen could confer rapid and sustained protection against inhalation anthrax in mice in a single-dose regimen in the presence of preexisting adenovirus immunity. The potency of the vaccine was greatly enhanced when codons of the antigen gene were optimized to match the tRNA pool found in human cells. In addition, an adenovirus vector encoding lethal factor can confer partial protection against inhalation anthrax and might be coadministered with a protective antigen-based vaccine. PMID:23100479

19 CFR 210.35 - Prehearing conferences.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 3 2010-04-01 2010-04-01 false Prehearing conferences. 210.35 Section 210.35 Customs Duties UNITED STATES INTERNATIONAL TRADE COMMISSION INVESTIGATIONS OF UNFAIR PRACTICES IN IMPORT TRADE ADJUDICATION AND ENFORCEMENT Prehearing Conferences and Hearings § 210.35 Prehearing conferences...

Supramolecular Nanoparticles for Molecular Diagnostics and Therapeutics

NASA Astrophysics Data System (ADS)

Chen, Kuan-Ju

Over the past decades, significant efforts have been devoted to explore the use of various nanoparticle-based systems in the field of nanomedicine, including molecular imaging and therapy. Supramolecular synthetic approaches have attracted lots of attention due to their flexibility, convenience, and modularity for producing nanoparticles. In this dissertation, the developmental story of our size-controllable supramolecular nanoparticles (SNPs) will be discussed, as well as their use in specific biomedical applications. To achieve the self-assembly of SNPs, the well-characterized molecular recognition system (i.e., cyclodextrin/adamantane recognition) was employed. The resulting SNPs, which were assembled from three molecular building blocks, possess incredible stability in various physiological conditions, reversible size-controllability and dynamic disassembly that were exploited for various in vitro and in vivo applications. An advantage of using the supramolecular approach is that it enables the convenient incorporation of functional ligands onto SNP surface that confers functionality ( e.g., targeting, cell penetration) to SNPs. We utilized SNPs for molecular imaging such as magnetic resonance imaging (MRI) and positron emission tomography (PET) by introducing reporter systems (i.e., radio-isotopes, MR contrast agents, and fluorophores) into SNPs. On the other hand, the incorporation of various payloads, including drugs, genes and proteins, into SNPs showed improved delivery performance and enhanced therapeutic efficacy for these therapeutic agents. Leveraging the powers of (i) a combinatorial synthetic approach based on supramolecular assembly and (ii) a digital microreactor, a rapid developmental pathway was developed that is capable of screening SNP candidates for the ideal structural and functional properties that deliver optimal performance. Moreover, SNP-based theranostic delivery systems that combine reporter systems and therapeutic payloads into a

Catalog of Courses and Conferences, 1972-1973.

ERIC Educational Resources Information Center

Defense Civil Preparedness Agency (DOD), Battle Creek, MI.

The types of courses, conferences, and workshops sponsored by the Defense Civil Preparedness Agency tuition-free are listed and described in this pamphlet. The training programs are not representative of all civil defense training available. The 21 courses and conferences listed are: Conferences for Public Officials; Conferences for Business and…

Effect of pH and chloroauric acid concentration on the geometry of gold nanoparticles obtained by photochemical synthesis

NASA Astrophysics Data System (ADS)

Conde Rodríguez, G. R.; Gauthier, G. H.; Ladeira, L. O.; Sanabria Cala, J. A.; Laverde Cataño, D.

2017-12-01

Due to their excellent surface properties, gold nanoparticles have been used in a wide range of applications from optics and catalysis to biology and cancer treatment by thermal therapy. Gold nanoparticles can absorb a large amount of radiation according to their geometry, such as nanospheres and nanorods. The importance of gold nanoparticles geometry is based on the electromagnetic spectrum wavelength where exists a greater absorption of radiation, which belongs to the visible region for nanospheres and ranges between visible and near infrared regions for nanorods, conferring greater biomedical applicability to the latter. When using photochemical synthesis method, which consists of reducing gold atoms to their metallic state with UV radiation, the geometry of gold nanoparticles depends on different variables such as: 1) pH, 2) concentration of chloroauric acid, 3) the surfactant, 4) concentration of silver nitrate, 5) temperature and 6) irradiation time. Therefore, in this study the geometry of the gold nanoparticles obtained by photochemical synthesis was determined as a function of solution pH and chloroauric acid concentration, using Spectrophotometry in the Ultraviolet Visible region (UV-vis) as characterization technique. From the analysis of the UV-vis spectra, it was determined that at an acidic pH the particles have two absorption bands corresponding to nanorods geometry, while at a basic pH only nanospheres are found and at a neutral pH the lower relative intensity of the second band indicates the simultaneous existence of the two geometries. The increase in the concentration of chloroauric acid produces a decrease in the amount of synthesized nanorods, seen as a decrease of the relative intensity of the second absorption band. Therefore, obtaining gold nanoparticles with nanorods geometry favours fields such as biomedicine, because they are capable of absorbing infrared radiation and can be used as photosensitive agents in localized thermal therapy

Nuclear Rocket Technology Conference

NASA Technical Reports Server (NTRS)

1966-01-01

The Lewis Research Center has a strong interest in nuclear rocket propulsion and provides active support of the graphite reactor program in such nonnuclear areas as cryogenics, two-phase flow, propellant heating, fluid systems, heat transfer, nozzle cooling, nozzle design, pumps, turbines, and startup and control problems. A parallel effort has also been expended to evaluate the engineering feasibility of a nuclear rocket reactor using tungsten-matrix fuel elements and water as the moderator. Both of these efforts have resulted in significant contributions to nuclear rocket technology. Many successful static firings of nuclear rockets have been made with graphite-core reactors. Sufficient information has also been accumulated to permit a reasonable Judgment as to the feasibility of the tungsten water-moderated reactor concept. We therefore consider that this technoIogy conference on the nuclear rocket work that has been sponsored by the Lewis Research Center is timely. The conference has been prepared by NASA personnel, but the information presented includes substantial contributions from both NASA and AEC contractors. The conference excludes from consideration the many possible mission requirements for nuclear rockets. Also excluded is the direct comparison of nuclear rocket types with each other or with other modes of propulsion. The graphite reactor support work presented on the first day of the conference was partly inspired through a close cooperative effort between the Cleveland extension of the Space Nuclear Propulsion Office (headed by Robert W. Schroeder) and the Lewis Research Center. Much of this effort was supervised by Mr. John C. Sanders, chairman for the first day of the conference, and by Mr. Hugh M. Henneberry. The tungsten water-moderated reactor concept was initiated at Lewis by Mr. Frank E. Rom and his coworkers. The supervision of the recent engineering studies has been shared by Mr. Samuel J. Kaufman, chairman for the second day of the

Conference Summary: First International Conference on Global Warming and the Next Ice Age

NASA Technical Reports Server (NTRS)

Wetzel, Peter J.; Chylek, Petr; Lesins, Glen; Starr, David OC. (Technical Monitor)

2002-01-01

The First International Conference on Global Warming and the Next Ice Age was convened in Halifax, Nova Scotia, August 19-24, 2001. The conference program began each day with a 30 minute live classical music performances of truly international quality before the beginning business. Ample time for panel discussions was also scheduled. The general public was invited to attend and participate in a special evening panel session on the last day of the conference. The unusual and somewhat provocative title of the conference was designed to attract diverse views on global climate change. This summary attempts to accurately reflect the tone and flavor of the lively discussions which resulted. Presentations ranged from factors forcing current climate to those in effect across the span of time from the Proterozoic "snowball Earth" epoch to 50,000 years in the future. Although, as should be expected, attendees at the conference arrived with opinions on some of the controversial issues regarding climate change, and no-one openly admitted to a 'conversion' from their initial point of view, the interdisciplinary nature of the formal presentations, poster discussions, panels, and abundant informal discourse helped to place the attendees' personal perspectives into a broader, more diversified context.

Probing nanoparticles and nanoparticle-conjugated biomolecules using time-of-flight secondary ion mass spectrometry.

PubMed

Kim, Young-Pil; Shon, Hyun Kyong; Shin, Seung Koo; Lee, Tae Geol

2015-01-01

Bio-conjugated nanoparticles have emerged as novel molecular probes in nano-biotechnology and nanomedicine and chemical analyses of their surfaces have become challenges. The time-of-flight (TOF) secondary ion mass spectrometry (SIMS) has been one of the most powerful surface characterization techniques for both nanoparticles and biomolecules. When combined with various nanoparticle-based signal enhancing strategies, TOF-SIMS can probe the functionalization of nanoparticles as well as their locations and interactions in biological systems. Especially, nanoparticle-based SIMS is an attractive approach for label-free drug screening because signal-enhancing nanoparticles can be designed to directly measure the enzyme activity. The chemical-specific imaging analysis using SIMS is also well suited to screen nanoparticles and nanoparticle-biomolecule conjugates in complex environments. This review presents some recent applications of nanoparticle-based TOF-SIMS to the chemical analysis of complex biological systems. © 2014 Wiley Periodicals, Inc.

US objectives generally achieved at broadcasting satellite international conference. Improvements can help in future conferences

NASA Astrophysics Data System (ADS)

1984-08-01

The implementation of broadcasting satellite service for the Western Hemisphere was planned. Broadcasting satellites transmit television programs and other information services from Earth orbit to home or office antennas. At the request of the Senate Appropriations Subcommittee on Commerce, Justice, State and the Judiciary, GAO reviewed conference results as compared to established conference objectives and examined the interagency coordination of U.S. participation in this international conference. The United States basically achieved its two most important conference objectives: adopting a technically and procedurally flexible plan for broadcasting satellite service and obtaining a sufficient allocation of satellite orbit slots and frequencies to meet domestic needs. The U.S. was unable, however, to obtain agreement on adopting a maximum signal power level for satellites. The Department of State could improve its preparation, internal coordination, and administrative support for future international conferences and recommends actions to the Secretary of State to improve its international telecommunications activities.

Ligand Size and Conformation Affect the Behavior of Nanoparticles Coated with in Vitro and in Vivo Protein Corona.

PubMed

Zhang, Huajin; Wu, Tianmu; Yu, Wenqi; Ruan, Shaobo; He, Qin; Gao, Huile

2018-03-14

Protein corona is immediately established on the surface of nanoparticles upon their introduction into biological milieu. Several studies have shown that the targeting efficiency of ligand-modified nanoparticles is attenuated or abolished owing to the protein adsorption. Here, transferrin receptor-targeting ligands, including LT7 (CHAIYPRH), DT7 (hrpyiahc, all d-form amino acids), and transferrin, were used to identify the influence of the ligand size and conformation on protein corona formation. The results showed that the targeting capacity of ligand-modified nanoparticles was lost after incubation with plasma in vitro, whereas it was partially retained after in vivo corona formation. Results from sodium dodecyl sulfate polyacrylamide gel electrophoresis and liquid chromatography-mass spectrometry revealed the difference in the composition of in vitro and in vivo corona, wherein the ligand size and conformation played a critical role. Differences were observed in cellular internalization and exocytosis profiles on the basis of the ligand and corona source.

37 CFR 351.7 - Settlement conference.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Settlement conference. 351.7... ROYALTY JUDGES RULES AND PROCEDURES PROCEEDINGS § 351.7 Settlement conference. A post-discovery settlement... with the Copyright Royalty Judges a written Joint Settlement Conference Report indicating the extent to...

6 CFR 13.19 - Prehearing conferences.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 6 Domestic Security 1 2010-01-01 2010-01-01 false Prehearing conferences. 13.19 Section 13.19 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY PROGRAM FRAUD CIVIL REMEDIES § 13.19 Prehearing conferences. (a) The ALJ may schedule prehearing conferences as appropriate. (b...

Incorporation of a recombinant Eimeria maxima IMP1 antigen into nanoparticles confers protective immunity against E. maxima challenge infection

USDA-ARS?s Scientific Manuscript database

The purpose of this study was to determine if incorporating a recombinant Eimeria maxima protein, namely rEmaxIMP1, into gold nanoparticles (NP) could improve the level of protective immunity against E. maxima challenge infection. Recombinant EmaxIMP1 was expressed in Escherchia coli as a poly-His f...

Visions for a sustainable world: A conference on science, technology and social responsibility. Conference report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This report summarizes the organization, activities, and outcomes of Student Pugwash USA`s 1992 International Conference, Visions for a Sustainable World: A Conference on Science, Technology and Social Responsibility. The conference was held June 14--20, 1992 at Emory University, and brought together 94 students and over 65 experts from industry, academe, and government. The conference addressed issues ranging from global environmental cooperation to the social impacts of the Human Genome Project to minority concerns in the sciences. It provided a valuable forum for talented students and professionals to engage in critical dialogue on many interdisciplinary issues at the juncture of science,more » technology and society. The conference challenged students -- the world`s future scientists, engineers, and political leaders -- to think broadly about global problems and to devise policy options that are viable and innovative. The success of the conference in stimulating interest, understanding, and enthusiasm about interdisciplinary global issues is clearly evident from both the participants` feedback and their continued involvement in Student Pugwash USA programs. Six working groups met each morning. The working group themes included: environmental challenges for developing countries; energy options: their social and environmental impact; health care in developing countries; changing dynamics of peace and global security; educating for the socially responsible use of technology; ethics and the use of genetic information. The conference was specifically designed to include mechanisms for ensuring its long-term impact. Participants were encouraged to focus on their individual role in helping resolve global issues. This was achieved through each participant`s development of a Personal Plan of Action, a plan which mapped out activities the student could undertake after the conference to continue the dialogue and work towards the resolution of global and local problems.« less

2 CFR 801.1112 - Conference.

Code of Federal Regulations, 2010 CFR

2010-01-01

... NONPROCUREMENT DEBARMENT AND SUSPENSION Limited Denial of Participation (Department of Veterans Affairs Optional... conference, the official imposing the sanction shall arrange such a conference with the participant or...

Antibacterial activity and cytotoxicity of multi-walled carbon nanotubes decorated with silver nanoparticles

PubMed Central

Seo, Youngmin; Hwang, Jangsun; Kim, Jieun; Jeong, Yoon; Hwang, Mintai P; Choi, Jonghoon

2014-01-01

Recently, various nanoscale materials, including silver (Ag) nanoparticles, have been actively studied for their capacity to effectively prevent bacterial growth. A critical challenge is to enhance the antibacterial properties of nanomaterials while maintaining their biocompatibility. The conjugation of multiple nanomaterials with different dimensions, such as spherical nanoparticles and high-aspect-ratio nanotubes, may increase the target-specific antibacterial capacity of the consequent nanostructure while retaining an optimal biocompatibility. In this study, multi-walled carbon nanotubes (MWCNTs) were treated with a mixture of acids and decorated with Ag nanoparticles via a chemical reduction of Ag cations by ethanol solution. The synthesized Ag-MWCNT complexes were characterized by transmission electron microscopy, X-ray diffractometry, and energy-dispersive X-ray spectroscopy. The antibacterial function of Ag-MWCNTs was evaluated against Methylobacterium spp. and Sphingomonas spp. In addition, the biocompatibility of Ag-MWCNTs was evaluated using both mouse liver hepatocytes (AML 12) and human peripheral blood mononuclear cells. Finally, we determined the minimum amount of Ag-MWCNTs required for a biocompatible yet effective antibacterial treatment modality. We report that 30 μg/mL of Ag-MWCNTs confers antibacterial functionality while maintaining minimal cytotoxicity toward both human and animal cells. The results reported herein would be beneficial for researchers interested in the efficient preparation of hybrid nanostructures and in determining the minimum amount of Ag-MWCNTs necessary to effectively hinder the growth of bacteria. PMID:25336943

Teaching of Psychology Conference: Ideas & Innovations. Proceedings from the Annual Conference (24th, Tarrytown, NY, March 19-20, 2010)

ERIC Educational Resources Information Center

Howell-Carter, Marya, Ed.; Gonder, Jennifer, Ed.

2010-01-01

Conference proceedings of the 24th Annual Conference on the Teaching of Psychology: Ideas and Innovations, sponsored by the Psychology Department of the State University of New York at Farmingdale. The conference theme for 2010 was Fostering, Assessing, and Sustaining Student Engagement. The conference featured two keynote addresses from prominent…

Real-Time Monitoring of Singlet Oxygen and Oxygen Partial Pressure During the Deep Photodynamic Therapy In Vitro.

PubMed

Li, Weitao; Huang, Dong; Zhang, Yan; Liu, Yangyang; Gu, Yueqing; Qian, Zhiyu

2016-09-01

Photodynamic therapy (PDT) is an effective noninvasive method for the tumor treatment. The major challenge in current PDT research is how to quantitatively evaluate therapy effects. To our best knowledge, this is the first time to combine multi-parameter detection methods in PDT. More specifically, we have developed a set of system, including the high-sensitivity measurement of singlet oxygen, oxygen partial pressure and fluorescence image. In this paper, the detection ability of the system was validated by the different concentrations of carbon quantum dots. Moreover, the correlation between singlet oxygen and oxygen partial pressure with laser irradiation was observed. Then, the system could detect the signal up to 0.5 cm tissue depth with 660 nm irradiation and 1 cm tissue depth with 980 nm irradiation by using up-conversion nanoparticles during PDT in vitro. Furthermore, we obtained the relationship among concentration of singlet oxygen, oxygen partial pressure and tumor cell viability under certain conditions. The results indicate that the multi-parameter detection system is a promising asset to evaluate the deep tumor therapy during PDT. Moreover, the system might be potentially used for the further study in biology and molecular imaging.

45 CFR 79.19 - Prehearing conferences.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 1 2010-10-01 2010-10-01 false Prehearing conferences. 79.19 Section 79.19 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION PROGRAM FRAUD CIVIL REMEDIES § 79.19 Prehearing conferences. (a) The ALJ may schedule prehearing conferences as appropriate. (b) Upon...

Making Conferences Human Places of Learning

ERIC Educational Resources Information Center

Kenny, Michael

2014-01-01

Open Space Technology is a cumbersome name for a participative conference model that enables dynamic inclusive engagement and challenges traditional, highly structured hierarchical conference formats. Based on self-organising systems, (Wenger, 1998) Open Space Technology conferences have an open process, start with no agenda and empower the most…

Molecular species forming at the α-Fe2O3 nanoparticle-aqueous solution interface.

PubMed

Ali, Hebatallah; Seidel, Robert; Pohl, Marvin N; Winter, Bernd

2018-05-21

We report on electronic structure measurements of the interface between hematite nanoparticles (6 nm diameter) and aqueous solutions. Using soft X-ray photoelectron spectroscopy from a liquid microjet we detect valence and core-level photoelectrons as well as Auger electrons from liquid water, from the nanoparticle-water interface, and from the interior of the aqueous-phase nanoparticles. Most noteworthy, the method is shown to be sufficiently sensitive for the detection of adsorbed hydroxyl species, resulting from H 2 O dissociation at the nanoparticle surface in aqueous solution. We obtain signal from surface OH from resonant, non-resonant, and from so-called partial-electron-yield X-ray absorption (PEY-XA) spectra. In addition, we report resonant photoelectron measurements at the iron 2p excitation. The respective Fe iron 2p 3/2 edge (L 3 -edge) PEY-XA spectra exhibit two main absorption peaks with their energies being sensitive to the chemical environment of the Fe 3+ ions at the nanoparticle-solution interface. This manifests in the 10 D q value which is a measure of the ligand-field strength. Furthermore, an observed intensity variation of the pre-peak, when comparing the PEY-XA spectra for different iron Auger-decay channels, can be assigned to different extents of electron delocalization. From the experimental fraction of local versus non-local autoionization signals we then find a very fast, approximately 1 fs, charge transfer time from interfacial Fe 3+ into the environment. The present study, which is complementary to ambient-pressure photoemission studies on solid-electrolyte systems, also highlights the multiple aspects of photoemission that need to be explored for a full characterization of the transition-metal-oxide nanoparticle surface in aqueous phase.

GE STEM Teacher's Conference

NASA Image and Video Library

2017-07-13

Education Specialists Lynn Dotson, left, of the NASA Public Engagement Center, and Lester Morales, right, of Texas State University's NASA STEM Educator Professional Development Collaborative, explain the Rocketry Engineering Design Challenge to teachers participating in the 2017 GE Foundation High School STEM Integration Conference at the Center for Space Education at NASA's Kennedy Space Center. High school teachers from across the country took part in the week-long conference, which is designed to explore effective ways for teachers, schools and districts from across the country to integrate STEM throughout the curriculum. The conference is a partnership between GE Foundation and the National Science Teachers Association.

Partial tooth gear bearings

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

2010-01-01

A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

Antimicrobial activity of biogenic silver nanoparticles, and silver chloride nanoparticles: an overview and comments.

PubMed

Durán, Nelson; Nakazato, Gerson; Seabra, Amedea B

2016-08-01

The antimicrobial impact of biogenic-synthesized silver-based nanoparticles has been the focus of increasing interest. As the antimicrobial activity of nanoparticles is highly dependent on their size and surface, the complete and adequate characterization of the nanoparticle is important. This review discusses the characterization and antimicrobial activity of biogenic synthesized silver nanoparticles and silver chloride nanoparticles. By revising the literature, there is confusion in the characterization of these two silver-based nanoparticles, which consequently affects the conclusion regarding to their antimicrobial activities. This review critically analyzes recent publications on the synthesis of biogenic silver nanoparticles and silver chloride nanoparticles by attempting to correlate the characterization of the nanoparticles with their antimicrobial activity. It was difficult to correlate the size of biogenic nanoparticles with their antimicrobial activity, since different techniques are employed for the characterization. Biogenic synthesized silver-based nanoparticles are not completely characterized, particularly the nature of capped proteins covering the nanomaterials. Moreover, the antimicrobial activity of theses nanoparticles is assayed by using different protocols and strains, which difficult the comparison among the published papers. It is important to select some bacteria as standards, by following international foundations (Pharmaceutical Microbiology Manual) and use the minimal inhibitory concentration by broth microdilution assays from Clinical and Laboratory Standards Institute, which is the most common assay used in antibiotic ones. Therefore, we conclude that to have relevant results on antimicrobial effects of biogenic silver-based nanoparticles, it is necessary to have a complete and adequate characterization of these nanostructures, followed by standard methodology in microbiology protocols.

Developing Mission-Focused Outcomes for a Professional Conference: The Case of the National Conference on Geography Education

ERIC Educational Resources Information Center

Waite, Jacqueline L.; Hume, Susan E.

2017-01-01

Conferences are principal mechanisms for professional organizations to advance their missions. Conference evaluations can measure mission-related outcomes in order to gauge an organization's impact on the professional growth and development of its community and other stakeholders. Using data from two recent conference evaluations, this article…

Molybdenum carbide supported nickel-molybdenum alloys for synthesis gas production via partial oxidation of surrogate biodiesel

NASA Astrophysics Data System (ADS)

Shah, Shreya; Marin-Flores, Oscar G.; Norton, M. Grant; Ha, Su

2015-10-01

In this study, NiMo alloys supported on Mo2C are synthesized by wet impregnation for partial oxidation of methyl oleate, a surrogate biodiesel, to produce syngas. When compared to single phase Mo2C, the H2 yield increases from 70% up to >95% at the carbon conversion of ∼100% for NiMo alloy nanoparticles that are dispersed over the Mo2C surface. Supported NiMo alloy samples are prepared at two different calcination temperatures in order to determine its effect on particle dispersion, crystalline phase and catalytic properties. The reforming test data indicate that catalyst prepared at lower calcination temperature shows better nanoparticle dispersion over the Mo2C surface, which leads to higher initial performance when compared to catalysts synthesized at higher calcination temperature. Activity tests using the supported NiMo alloy on Mo2C that are calcined at the lower temperature of 400 °C shows 100% carbon conversion with 90% H2 yield without deactivation due to coking over 24 h time-on-stream.

Durable antibacterial and UV protections of in situ synthesized zinc oxide nanoparticles onto cotton fabrics.

PubMed

Shaheen, Th I; El-Naggar, Mehrez E; Abdelgawad, Abdelrahman M; Hebeish, A

2016-02-01

Herein we represent a new discovery based on amine material called hexamethyltriethylene tetramine (HMTETA). We have observed that when an aqueous solution of Zn(NO3)·6H2O was added to aqueous solution of HMTETA followed by shaking for a time, the colorless solution was converted to milky color under the alkaline medium provided by HMTETA prior to formation of uniform zinc oxide nanoparticles (ZnO NPs). The latter are in situ formed within the cotton fabrics without the support of capping or other stabilizing agents. Obviously, then, the new made of formation of ZnO NPs speaks of a single-stage process where cotton fabric is immersed in a prepared solution of the new precursors through which binding of ZnO NPs into the textile fabrics takes place. Textile fabrics are, indeed, used as a template, which is capable of maintaining the size and surface distribution of the as-synthesized nanoparticles in a uniform domain. It is also likely that nanoparticles is confined inside the fibril and microfibrils of the cotton fibers. World-class facilities have been employed to follow up the synthesis of ZnO NPs, their characterization and their application to confer, in particular, high durable antibacterial and UV protective function on cotton fabrics. Copyright © 2015 Elsevier B.V. All rights reserved.

Unfolding and inactivation of proteins by counterions in protein-nanoparticles interaction.

PubMed

Ghosh, Goutam; Gaikwad, Pallavi S; Panicker, Lata; Nath, Bimalendu B; Mukhopadhyaya, Rita

2016-09-01

In this work, the structure and activity of proteins; such as, hen egg lysozyme (HEWL) and calf intestine alkaline phosphatase (CIAP); have been investigated after incubation with surface coated iron oxide nanoparticles (IONPs) in water. IONPs were coated with counterions bound charge-ligands and were named as the charge-ligand counterions iron oxide nanoparticles (CLC-IONPs). The coating was done with tri-lithium citrate (TLC) and tri-potassium citrate (TKC) to have negative surface charge of CLC-IONPs and Li(+) and K(+), respectively, as counterions. To have positive surface charge, IONPs were coated with cetylpyridinium chloride (CPC) and cetylpyridinium iodide (CPI) having Cl(-) and I(-), respectively, as counterions. The secondary structure of proteins was measured using far ultraviolet circular dichroism (CD) spectroscopy which showed that both proteins were irreversibly unfolded after incubation with CLC-IONPs. The unfolded proteins were seen to be functionally inactive, as confirmed through their activity assays, i.e., HEWL with Escherichia coli (E. coli) and CIAP with para-nitrophenyl phosphate (pNPP). Additionally, we have observed that monomeric hemoglobin (Hb) from radio-resistant insect Chironomus ramosus (ChHb) was also partially unfolded upon interaction with CLC-IONPs. This work clearly shows the role of counterions in protein inactivation via protein-nanoparticles interaction and, therefore, CLC-IONPs could be used for therapeutic purpose. Copyright © 2016 Elsevier B.V. All rights reserved.

Counter ion induced irreversible denaturation of hen egg white lysozyme upon electrostatic interaction with iron oxide nanoparticles: a predicted model.

PubMed

Ghosh, Goutam; Panicker, Lata; Ningthoujam, R S; Barick, K C; Tewari, R

2013-03-01

The effects of electrostatic interaction between the hen egg white lysozyme (HEWL) and the functionalized iron oxide nanoparticles (IONPs) have been investigated using several techniques, e.g., CD, DSC, ζ-potential, UV-visible spectroscopy, DLS, TEM. Nanoparticles (IONPs) were functionalized with three hydrophilic ligands, viz., poly(ethylene glycol) (PEG), trisodium citrate (TSC) and sodium triphosphate (STP); where both TSC and STP contain Na(+) counter ions. It has been observed that the secondary structure of HEWL was not affected by PEG functionalized IONPs, but was partially and almost completely perturbed by TSC and STP functionalized IONPs, respectively. The perturbation of the secondary structure was irreversible. We have predicted an interaction model to explain the origin of perturbation of HEWL structure. We have also investigated the stability of nanoparticles dispersions after interaction with HEWL and used the DLVO theory to explain results. Copyright © 2012 Elsevier B.V. All rights reserved.

Characterization of Lr75: a partial, broad-spectrum leaf rust resistance gene in wheat.

PubMed

Singla, Jyoti; Lüthi, Linda; Wicker, Thomas; Bansal, Urmil; Krattinger, Simon G; Keller, Beat

2017-01-01

Here, we describe a strategy to improve broad-spectrum leaf rust resistance by marker-assisted combination of two partial resistance genes. One of them represents a novel partial adult plant resistance gene, named Lr75. Leaf rust caused by the fungal pathogen Puccinia triticina is a damaging disease of wheat (Triticum aestivum L.). The combination of several, additively-acting partial disease resistance genes has been proposed as a suitable strategy to breed wheat cultivars with high levels of durable field resistance. The Swiss winter wheat cultivar 'Forno' continues to show near-immunity to leaf rust since its release in the 1980s. This resistance is conferred by the presence of at least six quantitative trait loci (QTL), one of which is associated with the morphological trait leaf tip necrosis. Here, we used a marker-informed strategy to introgress two 'Forno' QTLs into the leaf rust-susceptible Swiss winter wheat cultivar 'Arina'. The resulting backcross line 'ArinaLrFor' showed markedly increased leaf rust resistance in multiple locations over several years. One of the introgressed QTLs, QLr.sfr-1BS, is located on chromosome 1BS. We developed chromosome 1B-specific microsatellite markers by exploiting the Illumina survey sequences of wheat cv. 'Chinese Spring' and mapped QLr.sfr-1BS to a 4.3 cM interval flanked by the SSR markers gwm604 and swm271. QLr.sfr-1BS does not share a genetic location with any of the described leaf rust resistance genes present on chromosome 1B. Therefore, QLr.sfr-1BS is novel and was designated as Lr75. We conclude that marker-assisted combination of partial resistance genes is a feasible strategy to increase broad-spectrum leaf rust resistance. The identification of Lr75 adds a novel and highly useful gene to the small set of known partial, adult plant leaf rust resistance genes.

20 CFR 416.557 - Personal conference.

Code of Federal Regulations, 2010 CFR

2010-04-01

... notified in writing and given the dates, times and place of the file review and personal conference; the procedure for reviewing the claims file prior to the personal conference; the procedure for seeking a change... individual about the personal conference. The file review is always scheduled at least 5 days before the...

20 CFR 416.557 - Personal conference.

Code of Federal Regulations, 2011 CFR

2011-04-01

... notified in writing and given the dates, times and place of the file review and personal conference; the procedure for reviewing the claims file prior to the personal conference; the procedure for seeking a change... individual about the personal conference. The file review is always scheduled at least 5 days before the...

The Press Conferences of Eleanor Roosevelt.

ERIC Educational Resources Information Center

Beasley, Maurine H.

Newly discovered transcriptions of 87 of First Lady Eleanor Roosevelt's women-only press conferences held from 1933 to 1945 make possible an examination of the objectives, topics, and value of these conferences. By holding the conferences, Mrs. Roosevelt attributed to women an important function in the political communication process, and at the…

Stability and dewetting of metal nanoparticle filled thin polymer films: control of instability length scale and dynamics.

PubMed

Mukherjee, Rabibrata; Das, Soma; Das, Anindya; Sharma, Satinder K; Raychaudhuri, Arup K; Sharma, Ashutosh

2010-07-27

We investigate the influence of gold nanoparticle addition on the stability, dewetting, and pattern formation in ultrathin polymer-nanoparticle (NP) composite films by examining the length and time scales of instability, morphology, and dynamics of dewetting. For these 10-50 nm thick (h) polystyrene (PS) thin films containing uncapped gold nanoparticles (diameter approximately 3-4 nm), transitions from complete dewetting to arrested dewetting to absolute stability were observed depending on the concentration of the particles. Experiments show the existence of three distinct stability regimes: regime 1, complete dewetting leading to droplet formation for nanoparticle concentration of 2% (w/w) or below; regime 2, partial dewetting leading to formation of arrested holes for NP concentrations in the range of 3-6%; and regime 3, complete inhibition of dewetting for NP concentrations of 7% and above. Major results are (a) length scale of instability, where lambdaH approximately hn remains unchanged with NP concentration in regime 1 (n approximately 2) but increases in regime 2 with a change in the scaling relation (n approximately 3-3.5); (b) dynamics of instability and dewetting becomes progressively sluggish with an increase in the NP concentration; (c) there are distinct regimes of dewetting velocity at low NP concentrations; (d) force modulation AFM, as well as micro-Raman analysis, shows phase separation and aggregation of the gold nanoparticles within each dewetted polymer droplet leading to the formation of a metal core-polymer shell morphology. The polymer shell could be removed by washing in a selective solvent, thus exposing an array of bare gold nanoparticle aggregates.

Ordering nanoparticles with polymer brushes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a singlemore » layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. As a result, an interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.« less

Ordering nanoparticles with polymer brushes

NASA Astrophysics Data System (ADS)

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

2017-12-01

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a single layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. An interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.

Ordering nanoparticles with polymer brushes

DOE PAGES

Cheng, Shengfeng; Stevens, Mark J.; Grest, Gary S.

2017-12-08

Ordering nanoparticles into a desired super-structure is often crucial for their technological applications. We use molecular dynamics simulations to study the assembly of nanoparticles in a polymer brush randomly grafted to a planar surface as the solvent evaporates. Initially, the nanoparticles are dispersed in a solvent that wets the polymer brush. After the solvent evaporates, the nanoparticles are either inside the brush or adsorbed at the surface of the brush, depending on the strength of the nanoparticle-polymer interaction. For strong nanoparticle-polymer interactions, a 2-dimensional ordered array is only formed when the brush density is finely tuned to accommodate a singlemore » layer of nanoparticles. When the brush density is higher or lower than this optimal value, the distribution of nanoparticles shows large fluctuations in space and the packing order diminishes. For weak nanoparticle-polymer interactions, the nanoparticles order into a hexagonal array on top of the polymer brush as long as the grafting density is high enough to yield a dense brush. As a result, an interesting healing effect is observed for a low-grafting-density polymer brush that can become more uniform in the presence of weakly adsorbed nanoparticles.« less

Humid Heat Autoclaving of Hybrid Nanoparticles Achieved by Decreased Nanoparticle Concentration and Improved Nanoparticle Stability Using Medium Chain Triglycerides as a Modifier.

PubMed

Gou, Jingxin; Chao, Yanhui; Liang, Yuheng; Zhang, Ning; He, Haibing; Yin, Tian; Zhang, Yu; Xu, Hui; Tang, Xing

2016-09-01

Humid heat autoclaving is a facile technique widely used in the sterilization of injections, but the high temperature employed would destroy nanoparticles composed of biodegradable polymers. The aim of this study was to investigate whether incorporation of medium chain triglycerides (MCT) could stabilize nanoparticles composed of poly (ethylene glycol)-b-polycaprolactone (PEG-b-PCL) during autoclaving (121°C, 10 min). Polymeric nanoparticles with different MCT contents were prepared by dialysis. Block copolymer degradation was studied by GPC. The critical aggregation concentrations of nanoparticles at different temperatures were determined using pyrene fluorescence. The size, morphology and weight averaged molecular weight of pristine/autoclaved nanoparticles were studied using DLS, TEM and SLS, respectively. Drug loading content and release profile were determined using RP-HPLC. The protecting effect of MCT on nanoparticles was dependent on the amount of MCT incorporated. Nanoparticles with high MCT contents, which assumed an emulsion-like morphology, showed reduced block copolymer degradation and particle disassociation after incubation at 100°C for 24 h. Nanoparticles with high MCT content showed the lowest critical aggregation concentration (CAC) under either room temperature or 60°C and the lowest particle concentration among all samples. And the particle size, drug loading content, physical stability and release profile of nanoparticles with high MCT contents remained nearly unchanged after autoclaving. Incorporation of high amount of MCT changed the morphology of PEG-b-PCL based nanoparticles to an emulsion-like structure and the nanoparticles prepared could withstand autoclaving due to improved particle stability and decreased particle concentration caused by MCT incorporation.

Progress toward clonable inorganic nanoparticles

NASA Astrophysics Data System (ADS)

Ni, Thomas W.; Staicu, Lucian C.; Nemeth, Richard S.; Schwartz, Cindi L.; Crawford, David; Seligman, Jeffrey D.; Hunter, William J.; Pilon-Smits, Elizabeth A. H.; Ackerson, Christopher J.

2015-10-01

Pseudomonas moraviensis stanleyae was recently isolated from the roots of the selenium (Se) hyperaccumulator plant Stanleya pinnata. This bacterium tolerates normally lethal concentrations of SeO32- in liquid culture, where it also produces Se nanoparticles. Structure and cellular ultrastructure of the Se nanoparticles as determined by cellular electron tomography shows the nanoparticles as intracellular, of narrow dispersity, symmetrically irregular and without any observable membrane or structured protein shell. Protein mass spectrometry of a fractionated soluble cytosolic material with selenite reducing capability identified nitrite reductase and glutathione reductase homologues as NADPH dependent candidate enzymes for the reduction of selenite to zerovalent Se nanoparticles. In vitro experiments with commercially sourced glutathione reductase revealed that the enzyme can reduce SeO32- (selenite) to Se nanoparticles in an NADPH-dependent process. The disappearance of the enzyme as determined by protein assay during nanoparticle formation suggests that glutathione reductase is associated with or possibly entombed in the nanoparticles whose formation it catalyzes. Chemically dissolving the nanoparticles releases the enzyme. The size of the nanoparticles varies with SeO32- concentration, varying in size form 5 nm diameter when formed at 1.0 μM [SeO32-] to 50 nm maximum diameter when formed at 100 μM [SeO32-]. In aggregate, we suggest that glutathione reductase possesses the key attributes of a clonable nanoparticle system: ion reduction, nanoparticle retention and size control of the nanoparticle at the enzyme site.Pseudomonas moraviensis stanleyae was recently isolated from the roots of the selenium (Se) hyperaccumulator plant Stanleya pinnata. This bacterium tolerates normally lethal concentrations of SeO32- in liquid culture, where it also produces Se nanoparticles. Structure and cellular ultrastructure of the Se nanoparticles as determined by cellular

Non-amyloidogenic peptide tags for the regulatable self-assembling of protein-only nanoparticles.

PubMed

Unzueta, Ugutz; Ferrer-Miralles, Neus; Cedano, Juan; Zikung, Xu; Pesarrodona, Mireia; Saccardo, Paolo; García-Fruitós, Elena; Domingo-Espín, Joan; Kumar, Pradeep; Gupta, Kailash C; Mangues, Ramón; Villaverde, Antonio; Vazquez, Esther

2012-11-01

Controlling the self-assembling of building blocks as nanoscale entities is a requisite for the generation of bio-inspired vehicles for nanomedicines. A wide spectrum of functional peptides has been incorporated to different types of nanoparticles for the delivery of conventional drugs and nucleic acids, enabling receptor-specific cell binding and internalization, endosomal escape, cytosolic trafficking, nuclear targeting and DNA condensation. However, the development of architectonic tags to induce the self-assembling of functionalized monomers has been essentially neglected. We have examined here the nanoscale architectonic capabilities of arginine-rich cationic peptides, that when displayed on His-tagged proteins, promote their self-assembling as monodisperse, protein-only nanoparticles. The scrutiny of the cross-molecular interactivity cooperatively conferred by poly-arginines and poly-histidines has identified regulatable electrostatic interactions between building blocks that can also be engineered to encapsulate cargo DNA. The combined use of cationic peptides and poly-histidine tags offers an unusually versatile approach for the tailored design and biofabrication of protein-based nano-therapeutics, beyond the more limited spectrum of possibilities so far offered by self-assembling amyloidogenic peptides. Copyright © 2012 Elsevier Ltd. All rights reserved.

Protective efficacy of a Treponema pallidum Gpd DNA vaccine vectored by chitosan nanoparticles and fused with interleukin-2.

PubMed

Zhao, Feijun; Wang, Shiping; Zhang, Xiaohong; Gu, Weiming; Yu, Jian; Liu, Shuangquan; Zeng, Tiebing; Zhang, Yuejun; Wu, Yimou

2012-02-01

In the present study, immunomodulatory responses of a DNA vaccine constructed by fusing Treponema pallidum (Tp) glycerophosphodiester phosphodiesterase (Gpd) to interleukin-2 (IL-2) and using chitosan (CS) nanoparticles as vectors were investigated. New Zealand white rabbits were immunized by intramuscular inoculation of control DNAs, Tp Gpd DNA vaccine, or Gpd-IL-2 fusion DNA vaccine, which were vectored by CS nanoparticles. Levels of the anti-Gpd antibodies and levels of IL-2 and interferon-γ in rabbits were increased upon inoculation of Gpd-IL-2 fusion DNA vaccine, when compared with the inoculation with Gpd DNA vaccine, with CS vectoring increasing the effects. The Gpd-IL-2 fusion DNA vaccine efficiently enhanced the antigen-specific lymphocyte proliferative response. When the rabbits were challenged intradermally with 10(5) Tp (Nichols) spirochetes, the Gpd-IL-2 fusion DNA vaccine conferred better protection than the Gpd DNA vaccine (P < 0.05), as characterized by lower detectable amounts of dark field positive lesions (17.5%), lower ulcerative lesion scores (15%), and faster recovery. Individuals treated with the Tp Gpd-IL-2 fusion DNA vaccine vectored by CS nanoparticles had the lowest amounts of dark field positive lesions (10%) and ulcerations (5%) observed and the fastest recovery (42 days). These results indicate that the Gpd-IL-2 fusion DNA vaccine vectored by CS nanoparticles can efficiently induce Th1-dominant immune responses, improve protective efficacy against Tp spirochete infection, and effectively attenuate development of syphilitic lesions.

Annual Fuze Conference (44th)

DTIC Science & Technology

2000-04-11

Untitled Document 44th Fuze Conference.html[6/8/ 2017 10:33:34 AM] Files are in Adobe Acrobat 3.0 format. 44th Annual Fuze Conference 11-12 April...United Kingdom Wednesday, April 12, 2000 Untitled Document 44th Fuze Conference.html[6/8/ 2017 10:33:34 AM] Rockwell Collins’ Artillery GPS Engine...cooperation with U.S experts Mitch Stone Texarkana , Texas Day & Zimmermann, Inc. - Lone Star Division We do what we say! þ History and Evolution þ

Joint conference of iMEC 2015 (2nd International Manufacturing Engineering Conference & APCOMS 2015 (3rd Asia-Pacific Conference on Manufacturing Systems)

NASA Astrophysics Data System (ADS)

2016-02-01

The iMEC 2015 is the second International Manufacturing Engineering Conference organized by the Faculty of Manufacturing, Universiti Malaysia Pahang (UMP), held from 12-14th November 2015 in Kuala Lumpur, Malaysia, with a theme "Materials, Manufacturing and Systems for Tomorrow". For the first time, iMEC is organized together with 3rd Asia- Pacific Conference on Manufacturing System (APCOMS 2015) which owned by Fakulti Teknologi Industri, Institut Teknologi Bandung (ITB), Indonesia. This is an extended collaboration between UMP and ITB to intensify knowledge sharing and experiences between higher learning institutions. This conference (iMEC & APCOMS 2015) is a platform for knowledge exchange and the growth of ideas, particularly in manufacturing engineering. The conference aims to bring researchers, academics, scientists, students, engineers and practitioners from around the world together to present their latest findings, ideas, developments and applications related to manufacturing engineering and other related research areas. With rapid advancements in manufacturing engineering, iMEC is an appropriate medium for the associated community to keep pace with the changes. In 2015, the conference theme is “Materials, Manufacturing and Systems for Tomorrow” which reflects the acceleration of knowledge and technology in global manufacturing. The papers in these proceedings are examples of the work presented at the conference. They represent the tip of the iceberg, as the conference attracted over 200 abstracts from Malaysia, Indonesia, Japan, United Kingdom, Australia, India, Bangladesh, South Africa, Turkey and Morocco and 151 full papers were accepted in these proceedings. The conference was run in four parallel sessions with 160 presenters sharing their latest finding in the areas of manufacturing process, systems, advanced materials and automation. The first keynote presentation was given by Prof. B. S. Murthy (IIT, Madras) on "Nanomaterials with Exceptional

Glutathione reduces cytotoxicity of polyethyleneimine coated magnetic nanoparticles in CHO cells.

PubMed

Strojan, Klemen; Lojk, Jasna; Bregar, Vladimir B; Veranič, Peter; Pavlin, Mojca

2017-06-01

Polyethyleneimine (PEI) is a polycationic compound frequently used as a transfection agent. However, cytotoxicity of PEI and PEI-coated nanoparticles (PEI NPs) is still a major obstacle in its use. In this study we report a method for reducing cytotoxicity of PEI NPs by addition of glutathione in NPs synthesis. Glutathione reduced cytotoxic effects for at least 30% and decreased observed oxidative stress response compared to standard formulation. Results showed that the effect was partially due to reduced zeta potential and partially due to protective antioxidant properties of glutathione. Addition of glutathione to cell culture media with concurrent exposure to PEI NPs proved to be insufficient for cytotoxicity reduction. Additionally, we compared internalization pathways of both PEI NPs and GSH NPs. NPs were only found in endosomes and no NPs were found free in the cytosol, as would be expected according to so called proton sponge hypothesis. Copyright © 2017 Elsevier B.V. All rights reserved.

IFLA Council and General Conference: Conference Programme and Proceedings (65th, Bangkok, Thailand, August 20-28, 1999).

ERIC Educational Resources Information Center

International Federation of Library Associations and Institutions, The Hague (Netherlands).

This proceedings of the 1999 IFLA (International Federation of Library Associations and Institutions) annual conference contains: information on the current, future, and past conferences; a message from H.R.H. Princess Maha Chakri Sirindhorn, the patron of the Thai Library Association; a conference program; an alphabetical list of authors; and 112…

Nanoparticles in the clinic

PubMed Central

Anselmo, Aaron C.

2016-01-01

Abstract Nanoparticle/microparticle‐based drug delivery systems for systemic (i.e., intravenous) applications have significant advantages over their nonformulated and free drug counterparts. For example, nanoparticle systems are capable of delivering therapeutics and treating areas of the body that other delivery systems cannot reach. As such, nanoparticle drug delivery and imaging systems are one of the most investigated systems in preclinical and clinical settings. Here, we will highlight the diversity of nanoparticle types, the key advantages these systems have over their free drug counterparts, and discuss their overall potential in influencing clinical care. In particular, we will focus on current clinical trials for nanoparticle formulations that have yet to be clinically approved. Additional emphasis will be on clinically approved nanoparticle systems, both for their currently approved indications and their use in active clinical trials. Finally, we will discuss many of the often overlooked biological, technological, and study design challenges that impact the clinical success of nanoparticle delivery systems. PMID:29313004

Ready, Set, Conference! Mastering the Logistics

ERIC Educational Resources Information Center

McGuire, Margaret

2005-01-01

Planning to have a successful NAEYC Annual Conference experience is similar to preparing for a day of bargain shopping. In this article, the author describes how to get the most out of NAEYC's Annual Conference by analyzing their goals, preparing ahead, and being flexible. As a veteran conference attendee, the author learned from her mistakes and…

Nanoparticle Approaches against Bacterial Infections

PubMed Central

Gao, Weiwei; Thamphiwatana, Soracha; Angsantikul, Pavimol; Zhang, Liangfang

2014-01-01

Despite the wide success of antibiotics, the treatment of bacterial infection still faces significant challenges, particularly the emergence of antibiotic resistance. As a result, nanoparticle drug delivery platforms including liposomes, polymeric nanoparticles, dendrimers, and various inorganic nanoparticles have been increasingly exploited to enhance the therapeutic effectiveness of existing antibiotics. This review focuses on areas where nanoparticle approaches hold significant potential to advance the treatment of bacterial infection. These areas include targeted antibiotic delivery, environmentally responsive antibiotic delivery, combinatorial antibiotic delivery, nanoparticle-enabled antibacterial vaccination, and nanoparticle-based bacterial detection. In each area we highlight the innovative antimicrobial nanoparticle platforms and review their progress made against bacterial infections. PMID:25044325

ASE Annual Conference 2010

ERIC Educational Resources Information Center

McCune, Roger

2010-01-01

In this article, the author describes the ASE Annual Conference 2010 which was held at Nottingham after a gap of 22 years. As always, the main conference was preceded by International Day, an important event for science educators from across the world. There were two strands to the programme: (1) "What works for me?"--sharing new ideas…

Multilocation Video Conference By Optical Fiber

NASA Astrophysics Data System (ADS)

Gray, Donald J.

1982-10-01

An experimental system that permits interconnection of many offices in a single video conference is described. Video images transmitted to conference participants are selected by the conference chairman and switched by a microprocessor-controlled video switch. Speakers can, at their choice, transmit their own images or images of graphics they wish to display. Users are connected to the Switching Center by optical fiber subscriber loops that carry analog video, digitized telephone, data and signaling. The same system also provides user-selectable distribution of video program and video library material. Experience in the operation of the conference system is discussed.

Antimicrobial activity of silver nanoparticles encapsulated in poly-N-isopropylacrylamide-based polymeric nanoparticles.

PubMed

Qasim, Muhammad; Udomluck, Nopphadol; Chang, Jihyun; Park, Hansoo; Kim, Kyobum

2018-01-01

In this study, we analyzed the antimicrobial activities of poly- N -isopropylacrylamide (pNIPAM)-based polymeric nanoparticles encapsulating silver nanoparticles (AgNPs). Three sizes of AgNP-encapsulating pNIPAM- and pNIPAM-NH 2 -based polymeric nanoparticles were fabricated. Highly stable and uniformly distributed AgNPs were encapsulated within polymeric nanoparticles via in situ reduction of AgNO 3 using NaBH 4 as the reducing agent. The formation and distribution of AgNPs was confirmed by UV-visible spectroscopy, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry, respectively. Both polymeric nanoparticles showed significant bacteriostatic activities against Gram-negative ( Escherichia coli ) and Gram-positive ( Staphylococcus aureus ) bacteria depending on the nanoparticle size and amount of AgNO 3 used during fabrication.

Antimicrobial activity of silver nanoparticles encapsulated in poly-N-isopropylacrylamide-based polymeric nanoparticles

PubMed Central

Qasim, Muhammad; Udomluck, Nopphadol; Chang, Jihyun; Park, Hansoo; Kim, Kyobum

2018-01-01

In this study, we analyzed the antimicrobial activities of poly-N-isopropylacrylamide (pNIPAM)-based polymeric nanoparticles encapsulating silver nanoparticles (AgNPs). Three sizes of AgNP-encapsulating pNIPAM- and pNIPAM-NH2-based polymeric nanoparticles were fabricated. Highly stable and uniformly distributed AgNPs were encapsulated within polymeric nanoparticles via in situ reduction of AgNO3 using NaBH4 as the reducing agent. The formation and distribution of AgNPs was confirmed by UV-visible spectroscopy, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry, respectively. Both polymeric nanoparticles showed significant bacteriostatic activities against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria depending on the nanoparticle size and amount of AgNO3 used during fabrication. PMID:29379284

Computational analysis of non-Newtonian boundary layer flow of nanofluid past a semi-infinite vertical plate with partial slip

NASA Astrophysics Data System (ADS)

Amanulla, C. H.; Nagendra, N.; Suryanarayana Reddy, M.

2018-03-01

An analysis of this paper is examined, two-dimensional, laminar with heat and mass transfer of natural convective nanofluid flow past a semi-infinite vertical plate surface with velocity and thermal slip effects are studied theoretically. The coupled governing partial differential equations are transformed to ordinary differential equations by using non-similarity transformations. The obtained ordinary differential equations are solved numerically by a well-known method named as Keller Box Method (KBM). The influences of the emerging parameters i.e. Casson fluid parameter (β), Brownian motion parameter (Nb), thermophoresis parameter (Nt), Buoyancy ratio parameter (N), Lewis number (Le), Prandtl number (Pr), Velocity slip factor (Sf) and Thermal slip factor (ST) on velocity, temperature and nano-particle concentration distributions is illustrated graphically and interpreted at length. The major sources of nanoparticle migration in Nanofluids are Thermophoresis and Brownian motion. A suitable agreement with existing published literature is made and an excellent agreement is observed for the limiting case and also validation of solutions with a Nakamura tridiagonal method has been included. It is observed that nanoparticle concentrations on surface decreases with an increase in slip parameter. The study is relevant to enrobing processes for electric-conductive nano-materials, of potential use in aerospace and other industries.

The Conference Proceedings of the 2001 Air Transport Research Society (ATRS) of the WCTR Society. Volume 1

NASA Technical Reports Server (NTRS)

Lee, Yeong-Heok (Editor); Bowen, Brent D. (Editor); Tarry, Scott E. (Editor)

2001-01-01

The ATRS held its Annual conference at Jeju Island, Korea in July 2001. The conference was a success with nearly 140 participants including 70 presenters. This report contains presentations from Volume 1 on the following: Airline and Travel Agent Relationships in Asia;Benchmarking Aviation Safety in the Commercial Airline Industry;Impact of Frequent Flyer Program on the Demand for Air Travel; Application of Genetic Algorithm on Airline Schedule;The Effects of Dual Carrier Designation and Partial Liberalization: The Case of Canada;Defense of Air Carriers and Air Agencies in FAA Enforcement proceedin gs - Damage Control Before the Case Arises; Cost Incentives for Airline Mergers? - An examination on the cost impact of U.S. airline mergers and acquisitions;Airport Regulation, Airline Competition and Canada's Airport System; Airline Competition: The Case of Israel's Domestic Doupoly; Non-Financial Indicators of Airline Distress: A Conceptual Approach;and Airport Privatization: An Empirical Analysis of Financial and Operational Efficiency.

Characteristics of epoxy resin/SiO2 nanocomposite insulation: effects of plasma surface treatment on the nanoparticles.

PubMed

Yan, Wei; Phung, B T; Han, Zhao Jun; Ostrikov, Kostya

2013-05-01

The present study compares the effects of two different material processing techniques on modifying hydrophilic SiO2 nanoparticles. In one method, the nanoparticles undergo plasma treatment by using a custom-developed atmospheric-pressure non-equilibrium plasma reactor. With the other method, they undergo chemical treatment which grafts silane groups onto their surface and turns them into hydrophobic. The treated nanoparticles are then used to synthesize epoxy resin-based nanocomposites for electrical insulation applications. Their characteristics are investigated and compared with the pure epoxy resin and nanocomposite fabricated with unmodified nanofillers counterparts. The dispersion features of the nanoparticles in the epoxy resin matrix are examined through scanning electron microscopy (SEM) images. All samples show evidence that the agglomerations are smaller than 30 nm in their diameters. This indicates good dispersion uniformity. The Weibull plot of breakdown strength and the recorded partial discharge (PD) events of the epoxy resin/plasma-treated hydrophilic SiO2 nanocomposite (ER/PTI) suggest that the plasma-treated specimen yields higher breakdown strength and lower PD magnitude as compared to the untreated ones. In contrast, surprisingly, lower breakdown strength is found for the nanocomposite made by the chemically treated hydrophobic particles, whereas the PD magnitude and PD numbers remain at a similar level as the plasma-treated ones.

Tuning the structure of thermosensitive gold nanoparticle monolayers.

PubMed

Rezende, Camila A; Shan, Jun; Lee, Lay-Theng; Zalczer, Gilbert; Tenhu, Heikki

2009-07-23

Gold nanoparticles grafted with poly(N-isopropylacrylamide) (PNIPAM) are rendered amphiphilic and thermosensitive. When spread on the surface of water, they form stable Langmuir monolayers that exhibit surface plasmon resonance. Using Langmuir balance and contrast-matched neutron reflectivity, the detailed structural properties of these nanocomposite monolayers are revealed. At low surface coverage, the gold nanoparticles are anchored to the interface by an adsorbed PNIPAM layer that forms a thin and compact pancake structure. Upon isothermal compression (T=20 degrees C), the adsorbed layer thickens with partial desorption of polymer chains to form brush structures. Two distinct polymer conformations thus coexist: an adsorbed conformation that assures stability of the monolayer, and brush structures that dangle in the subphase. An increase in temperature to 30 degrees C results in contractions of both adsorbed and brush layers with a concomitant decrease in interparticle distance, indicating vertical as well as lateral contractions of the graft polymer layer. The reversibility of this thermal response is also shown by the contraction-expansion of the polymer layers in heating-cooling cycles. The structure of the monolayer can thus be tuned by compression and reversibly by temperature. These compression and thermally induced conformational changes are discussed in relation to optical properties.

Tailorable thiolated trimethyl chitosans for covalently stabilized nanoparticles.

PubMed

Verheul, Rolf J; van der Wal, Steffen; Hennink, Wim E

2010-08-09

A novel four-step method is presented to synthesize partially thiolated trimethylated chitosan (TMC) with a tailorable degree of quaternization and thiolation. First, chitosan was partially N-carboxylated with glyoxylic acid and sodium borohydride. Next, the remaining amines were quantitatively dimethylated with formaldehyde and sodium borohydride and then quaternized with iodomethane in NMP. Subsequently, these partially carboxylated TMCs dissolved in water were reacted with cystamine at pH 5.5 using EDC as coupling agent. After addition of DTT and dialysis, thiolated TMCs were obtained, varying in degree of quaternization (25-54%) and degree of thiolation (5-7%), as determined with (1)H NMR and Ellman's assay. Gel permeation chromatography with light scattering detection indicated limited intermolecular cross-linking. All thiolated TMCs showed rapid oxidation to yield disulfide cross-linked TMC at pH 7.4, while the thiolated polymers were rather stable at pH 4.0. When Calu-3 cells were used, XTT and LDH cell viability tests showed a slight reduction in cytotoxicity for thiolated TMCs as compared to the nonthiolated polymers with similar DQs. Positively charged nanoparticles loaded with fluorescently labeled ovalbumin were made from thiolated TMCs and thiolated hyaluronic acid. The stability of these particles was confirmed in 0.8 M NaCl, in contrast to particles made from nonthiolated polymers that dissociated under these conditions, demonstrating that the particles were held together by intermolecular disulfide bonds.

Metalloproteins and phytochelatin synthase may confer protection against zinc oxide nanoparticle induced toxicity in Caenorhabditis elegans.

PubMed

Polak, Natasa; Read, Daniel S; Jurkschat, Kerstin; Matzke, Marianne; Kelly, Frank J; Spurgeon, David J; Stürzenbaum, Stephen R

2014-03-01

Zinc oxide nanoparticles (ZnONPs) are used in large quantities by the cosmetic, food and textile industries. Here we exposed Caenorhabditis elegans wild-type and a metal sensitive triple knockout mutant (mtl-1;mtl-2;pcs-1) to ZnONPs (0-50mg/L) to study strain and exposure specific effects on transcription, reactive oxygen species generation, the biomolecular phenotype (measured by Raman microspectroscopy) and key endpoints of the nematode life cycle (growth, reproduction and lifespan). A significant dissolution effect was observed, where dissolved ZnO constituted over 50% of total Zn within a two day exposure to the test medium, suggesting that the nominal exposure to pure ZnONPs represents in vivo, at best, a mixture exposure of ionic zinc and nanoparticles. Nevertheless, the analyses provided evidence that the metallothioneins (mtl-1 and mtl-2), the phytochelatin synthase (pcs-1) and an apoptotic marker (cep-1) were transcriptionally activated. In addition, the DCFH-DA assay provided in vitro evidence of the oxidative potential of ZnONPs in the metal exposure sensitive triple mutant. Raman spectroscopy highlighted that the biomolecular phenotype changes significantly in the mtl-1;mtl-2;pcs-1 triple knockout worm upon ZnONP exposure, suggesting that these metalloproteins are instrumental in the protection against cytotoxic damage. Finally, ZnONP exposure was shown to decrease growth and development, reproductive capacity and lifespan, effects which were amplified in the triple knockout. By combining diverse toxicological strategies, we identified that individuals (genotypes) housing mutations in key metalloproteins and phytochelatin synthase are more susceptible to ZnONP exposure, which underlines their importance to minimize ZnONP induced toxicity. Copyright © 2013 Elsevier Inc. All rights reserved.

Inverse Scattering and Applications. Proceedings of Conference on Inverse Scattering on the Line, Held in Amherst, Massachusetts on June 7 - 13, 1990

DTIC Science & Technology

1990-01-01

J. Laurie Snell S. A. Amitsur, D. J. Saltman, and 2 Proceedings of the conference on G. B. Seligman , Editors integration, topology, and geometry in...Rational constructions of modules 17 Nonlinear partial differential equations. for simple Lie algebras, George B. Joel A. Smoller, Editor Seligman 18...number theory, Michael R. Stein and Linda Keen, Editor R. Keith Dennis, Editors 65 Logic and combinatorics, Stephen G. 84 Partition problems in

Cerium oxide nanoparticles protect rodent lungs from hypobaric hypoxia-induced oxidative stress and inflammation.

PubMed

Arya, Aditya; Sethy, Niroj Kumar; Singh, Sushil Kumar; Das, Mainak; Bhargava, Kalpana

2013-01-01

Cerium oxide nanoparticles (nanoceria) are effective at quenching reactive oxygen species (ROS) in cell culture and animal models. Although nanoceria reportedly deposit in lungs, their efficacy in conferring lung protection during oxidative stress remains unexplored. Thus, the study evaluated the protective efficacy of nanoceria in rat lung tissue during hypobaric hypoxia. A total of 48 animals were randomly divided into four equal groups (control [C], nanoceria treated [T], hypoxia [H], and nanoceria treated plus hypoxia [T+H]). Animals were injected intraperitoneally with either a dose of 0.5 μg/kg body weight/week of nanoceria (T and T+H groups) or vehicle (C and H groups) for 5 weeks. After the final dose, H and T+H animals were challenged with hypobaric hypoxia, while C and T animals were maintained at normoxia. Lungs were isolated and homogenate was obtained for analysis of ROS, lipid peroxidation, glutathione, protein carbonylation, and 4-hydroxynonenal-adduct formation. Plasma was used for estimating major inflammatory cytokines using enzyme-linked immunosorbent assay. Intact lung tissues were fixed and both transmission electron microscopy and histopathological examinations were carried out separately for detecting internalization of nanoparticles as well as altered lung morphology. Spherical nanoceria of 7-10 nm diameter were synthesized using a microemulsion method, and the lung protective efficacy of the nanoceria evaluated during hypobaric hypoxia. With repeated intraperitoneal injections of low micromole concentration, we successfully localized the nanoceria in rodent lung without any inflammatory response. The lung-deposited nanoceria limited ROS formation, lipid peroxidation, and glutathione oxidation, and prevented oxidative protein modifications like nitration and carbonyl formation during hypobaric hypoxia. We also observed reduced lung inflammation in the nanoceria-injected lungs, supporting the anti-inflammatory properties of nanoceria

The 2009 U.N. Durban Review Conference: Follow-Up to the 2001 U.N. World Conference Against Racism

DTIC Science & Technology

2008-11-20

Order Code RL34754 The 2009 U.N. Durban Review Conference: Follow-Up to the 2001 U.N. World Conference Against Racism November 20, 2008 Luisa...information if it does not display a currently valid OMB control number. 1. REPORT DATE 20 NOV 2008 2. REPORT TYPE 3. DATES COVERED 00-00-2008 to 00-00...2008 4. TITLE AND SUBTITLE The 2009 U.N. Durban Review Conference: Follow-Up to the 2001 U.N. World Conference Against Racism 5a. CONTRACT NUMBER

Can More Nanoparticles Induce Larger Viscosities of Nanoparticle-Enhanced Wormlike Micellar System (NEWMS)?

PubMed

Zhao, Mingwei; Zhang, Yue; Zou, Chenwei; Dai, Caili; Gao, Mingwei; Li, Yuyang; Lv, Wenjiao; Jiang, Jianfeng; Wu, Yining

2017-09-18

There have been many reports about the thickening ability of nanoparticles on the wormlike micelles in the recent years. Through the addition of nanoparticles, the viscosity of wormlike micelles can be increased. There still exists a doubt: can viscosity be increased further by adding more nanoparticles? To answer this issue, in this work, the effects of silica nanoparticles and temperature on the nanoparticles-enhanced wormlike micellar system (NEWMS) were studied. The typical wormlike micelles (wormlike micelles) are prepared by 50 mM cetyltrimethyl ammonium bromide (CTAB) and 60 mM sodium salicylate (NaSal). The rheological results show the increase of viscoelasticity in NEWMS by adding nanoparticles, with the increase of zero-shear viscosity and relaxation time. However, with the further increase of nanoparticles, an interesting phenomenon appears. The zero-shear viscosity and relaxation time reach the maximum and begin to decrease. The results show a slight increasing trend for the contour length of wormlike micelles by adding nanoparticles, while no obvious effect on the entanglement and mesh size. In addition, with the increase of temperature, remarkable reduction of contour length and relaxation time can be observed from the calculation. NEWMS constantly retain better viscoelasticity compared with conventional wormlike micelles without silica nanoparticles. According to the Arrhenius equation, the activation energy E a shows the same increase trend of NEWMS. Finally, a mechanism is proposed to explain this interesting phenomenon.

Preparation of gold nanoparticles by surfactant-promoted reductive reaction without extra reducing agent.

PubMed

Tang, Junqi; Huang, Jiamin; Man, Shi-Qing

2013-02-15

Cetyltrimethyl ammonium bromide (CTAB) has been extensively applied in the solution-phase synthesis of many types of colloidal nanoparticles. However, the uses of CTAB were mainly considered as template or capping agents to form controllable shape and protect the product from agglomeration. Here it was discovered that CATB could serve as a very mild reductant to reduce gold salt precursors preparing gold nanoparticles (GNPs) at base environment. CTAB acted as the reducing agent suffering a partial degradation and forming CTA macro radicals. FTIR proved the formation of CCl and/or CBr bond after CTAB degraded. The characterization of synthesized GNPs was examined by UV-Vis spectra, TEM and XRD. Several factors affecting the process of reaction, such as the amount of NaOH, the molar ratio of CTAB and HAuCl(4), the reaction temperature, the effect of light and oxygen, and stirring were discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Fabrication and analysis of Cr-doped ZnO nanoparticles from the gas phase.

PubMed

Schneider, L; Zaitsev, S V; Jin, W; Kompch, A; Winterer, M; Acet, M; Bacher, G

2009-04-01

High quality Cr-doped ZnO nanoparticles from the gas phase were prepared and investigated with respect to their structural, optical and magnetic properties. The extended x-ray absorption fine structure and the x-ray absorption near edge structure of the particles verify that after nanoparticle preparation Cr is incorporated as Cr3+ ) at least partially on sites with a 4-fold oxygen configuration, most likely on a Zn site, into the wurtzite lattice. Despite the fact that Cr is known to act as an efficient non-radiative loss centre for near band gap emission (NBE), a pronounced NBE is obtained up to room temperature even for a nominal Cr concentration of 10 at.%. Annealing at 1000 degrees C results in a significant improvement of the photoluminescence efficiency and a reduced PL linewidth down to 2.9 meV at low temperatures while the structural and magnetic data indicate the formation of ZnCr2O4 clusters.

ASM Conference on Prokaryotic Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaplan, H. B.

2005-07-13

Support was provided by DOE for the 2nd ASM Conference on Prokaryotic Development. The final conference program and abstracts book is attached. The conference presentations are organized around topics that are central to the current research areas in prokaryotic development. The program starts with topics that involve relatively simple models systems and ends with systems that are more complex. The topics are: i) the cell cycle, ii) the cytoskeleton, iii) morphogenesis, iv) developmental transcription, v) signaling, vi) multicellularity, and vii) developmental diversity and symbiosis. The best-studied prokaryotic development model systems will be highlighted at the conference through research presentations bymore » leaders in the field. Many of these systems are also model systems of relevance to the DOE mission including carbon sequestration (Bradyrizobium, Synechococcus), energy production (Anabaena, Rhodobacter) and bioremediation (Caulobacter, Mesorhizobium). In addition, many of the highlighted organisms have important practical applications; the actinomycetes and myxobacteria produce antimicrobials that are of commercial interest. It is certain that the cutting-edge science presented at the conference will be applicable to the large group of bacteria relevant to the DOE mission.« less

Drosophila Longevity Assurance Conferred by Reduced Insulin Receptor Substrate Chico Partially Requires d4eBP.

PubMed

Bai, Hua; Post, Stephanie; Kang, Ping; Tatar, Marc

2015-01-01

Mutations of the insulin/IGF signaling (IIS) pathway extend Drosophila lifespan. Based on genetic epistasis analyses, this longevity assurance is attributed to downstream effects of the FOXO transcription factor. However, as reported FOXO accounts for only a portion of the observed longevity benefit, suggesting there are additional outputs of IIS to mediate aging. One candidate is target of rapamycin complex 1 (TORC1). Reduced TORC1 activity is reported to slow aging, whereas reduced IIS is reported to repress TORC1 activity. The eukaryotic translation initiation factor 4E binding protein (4E-BP) is repressed by TORC1, and activated 4E-BP is reported to increase Drosophila lifespan. Here we use genetic epistasis analyses to test whether longevity assurance mutants of chico, the Drosophila insulin receptor substrate homolog, require Drosophila d4eBP to slow aging. In chico heterozygotes, which are robustly long-lived, d4eBP is required but not sufficient to slow aging. Remarkably, d4eBP is not required or sufficient for chico homozygotes to extend longevity. Likewise, chico heterozygote females partially require d4eBP to preserve age-dependent locomotion, and both chico genotypes require d4eBP to improve stress-resistance. Reproduction and most measures of growth affected by either chico genotype are always independent of d4eBP. In females, chico heterozygotes paradoxically produce more rather than less phosphorylated 4E-BP (p4E-BP). Altered IRS function within the IIS pathway of Drosophila appears to have partial, conditional capacity to regulate aging through an unconventional interaction with 4E-BP.

A nebulized gelatin nanoparticle-based CpG formulation is effective in immunotherapy of allergic horses.

PubMed

Klier, John; Fuchs, Sebastian; May, Anna; Schillinger, Ulrike; Plank, Christian; Winter, Gerhard; Coester, Conrad; Gehlen, Heidrun

2012-06-01

In the recent years, nanotechnology has boosted the development of potential drug delivery systems and material engineering on nanoscale basis in order to increase drug specificity and reduce side effects. A potential delivery system for immunostimulating agents such as cytosine-phosphate-guanine-oligodeoxynucleotides (CpG-ODN) needs to be developed to maximize the efficacy of immunotherapy against hypersensitivity. In this study, an aerosol formulation of biodegradable, biocompatible and nontoxic gelatin nanoparticle-bound CpG-ODN 2216 was used to treat equine recurrent airway obstruction in a clinical study. Bronchoalveolar lavage fluid was obtained from healthy and allergic horses to quantify Th1/Th2 cytokine levels before and after inhalation regimen. Full clinical examinations were performed to evaluate the therapeutic potential of this nebulized gelatin nanoparticle-based CpG formulation. Most remarkable was that regulatory anti-inflammatory and anti-allergic cytokine IL-10 expression was significantly triggered by five consecutive inhalations. Thorough assessment of clinical parameters following nanoparticle treatment indicated a partial remission of the allergic condition. Thus this study, for the first time, showed effectiveness of colloidal nanocarrier-mediated immunotherapy in food-producing animals with potential future applicability to other species including humans.

Conference Scene: Personalized Medicine comes to Harvard.

PubMed

Greenberg, Tarryn

2012-01-01

The Seventh Annual Harvard Personalized Medicine Conference was held at The Joseph B Martin Conference Center at the Harvard Medical School in Boston, MA, USA on the 9-10 November 2011. The 2-day conference program was designed to highlight the impact that personalized medicine is currently making clinically as it enters the healthcare delivery system. Going forward, policies, plans and actions of stakeholders including those from government, academia and the private sector need to be informed and guided by recent experience - all of which the conference program set out to explore. The conference attracted over 600 national and international thought leaders all involved in personalized healthcare.

Towards development of novel immunization strategies against leishmaniasis using PLGA nanoparticles loaded with kinetoplastid membrane protein-11.

PubMed

Santos, Diego M; Carneiro, Marcia W; de Moura, Tatiana R; Fukutani, Kiyoshi; Clarencio, Jorge; Soto, Manuel; Espuelas, Socorro; Brodskyn, Claudia; Barral, Aldina; Barral-Netto, Manoel; de Oliveira, Camila I

2012-01-01

Vaccine development has been a priority in the fight against leishmaniases, which are vector-borne diseases caused by Leishmania protozoa. Among the different immunization strategies employed to date is inoculation of plasmid DNA coding for parasite antigens, which has a demonstrated ability to induce humoral and cellular immune responses. In this sense, inoculation of plasmid DNA encoding Leishmania kinetoplasmid membrane protein-11 (KMP-11) was able to confer protection against visceral leishmaniasis. However, recently the use of antigen delivery systems such as poly(lactic-co-glycolic acid) (PLGA) nanoparticles has also proven effective for eliciting protective immune responses. In the present work, we tested two immunization strategies with the goal of obtaining protection, in terms of lesion development and parasite load, against cutaneous leishmaniasis caused by L. braziliensis. One strategy involved immunization with plasmid DNA encoding L. infantum chagasi KMP-11. Alternatively, mice were primed with PLGA nanoparticles loaded with the recombinant plasmid DNA and boosted using PLGA nanoparticles loaded with recombinant KMP-11. Both immunization strategies elicited detectable cellular immune responses with the presence of both proinflammatory and anti-inflammatory cytokines; mice receiving the recombinant PLGA nanoparticle formulations also demonstrated anti-KMP-11 IgG1 and IgG2a. Mice were then challenged with L. braziliensis, in the presence of sand fly saliva. Lesion development was not inhibited following either immunization strategy. However, immunization with PLGA nanoparticles resulted in a more prominent reduction in parasite load at the infection site when compared with immunization using plasmid DNA alone. This effect was associated with a local increase in interferon-gamma and in tumor necrosis factor-alpha. Both immunization strategies also resulted in a lower parasite load in the draining lymph nodes, albeit not significantly. Our results

Clinical conferences for physicians: Who sets the agenda?

PubMed

Abakumova, T R; Safina, A F; Ziganshina, L E

2015-01-01

Clinical conferences are generally defined as scheduled events at which practicing physicians themselves present to their colleagues interesting clinical cases, share their new experiences and learn about the latest achievements of medical science and practice. The value of a clinical conference is thought to be in direct communication between physicians, in analysis of topical issues in a given specialty with the aim to improve the quality of care. Speakers based on their own observations and studies reveal the most urgent problems, analyze results and offer potential decisions to their colleagues interested in the same questions. The event format may be different: workshops, highly specialized sections, round tables and seminars with participation of the leading specialists in a given field. These conferences are generally organised by the Ministries and Departments of Health, by leading research and/or educational institutions in the field, by recognised medical centres and other institutions. Recently pharmaceutical companies got actively involved in medical events, acting as sponsors of various scientific conferences and congresses, however threatening the mission of these events [1]. This brings up some uneasy questions: who are the medical conferences for? Who is in charge of setting the conference agenda? Do they contribute to evidence-based medicine; do they contribute to better health? Unfortunately, there is a trend to duplication or multiplication of conferences: various agencies and departments deliver the same conferences, presentations at which are often pre-arranged by pharmaceutical companies and do not have clear scientific novelty, while the conferences themselves have largely transformed into advertising of new pharmaceuticals or new technologies [2]. Pharmaceutical corporations sponsor invited speakers paying for their trips and paying honoraria, organising cocktail parties as part of medical activities. With the help of leading experts with

ARC Conference Showcases Telecommunications Services.

ERIC Educational Resources Information Center

Baldwin, Fred D.

1996-01-01

The Appalachian Regional Commission's 1996 Conference, "Building Blocks for Using Telecommunications and Information Technology," held in Binghamton, New York, focused on the role of telecommunications in Appalachia in education and training, telemedicine, business, and government. Highlights conference presentations on special…

Using ClinicalTrials.gov to supplement information in ophthalmology conference abstracts about trial outcomes: a comparison study.

PubMed

Scherer, Roberta W; Huynh, Lynn; Ervin, Ann-Margret; Dickersin, Kay

2015-01-01

Including results from unpublished randomized controlled trials (RCTs) in a systematic review may ameliorate the effect of publication bias in systematic review results. Unpublished RCTs are sometimes described in abstracts presented at conferences, included in trials registers, or both. Trial results may not be available in a trials register and abstracts describing RCT results often lack study design information. Complementary information from a trials register record may be sufficient to allow reliable inclusion of an unpublished RCT only available as an abstract in a systematic review. We identified 496 abstracts describing RCTs presented at the 2007 to 2009 Association for Research in Vision and Ophthalmology (ARVO) meetings; 154 RCTs were registered in ClinicalTrials.gov. Two persons extracted verbatim primary and non-primary outcomes reported in the abstract and ClinicalTrials.gov record. We compared each abstract outcome with all ClinicalTrials.gov outcomes and coded matches as complete, partial, or no match. We identified 800 outcomes in 152 abstracts (95 primary [51 abstracts] and 705 [141 abstracts] non-primary outcomes). No outcomes were reported in 2 abstracts. Of 95 primary outcomes, 17 (18%) agreed completely, 53 (56%) partially, and 25 (26%) had no match with a ClinicalTrials.gov primary or non-primary outcome. Among 705 non-primary outcomes, 56 (8%) agreed completely, 205 (29%) agreed partially, and 444 (63%) had no match with a ClinicalTrials.gov primary or non-primary outcome. Among the 258 outcomes partially agreeing, we found additional information on the time when the outcome was measured more often in ClinicalTrials.gov than in the abstract (141/258 (55%) versus 55/258 (21%)). We found no association between the presence of non-matching "new" outcomes and year of registration, time to registry update, industry sponsorship, or multi-center status. Conference abstracts may be a valuable source of information about results for outcomes of

Using ClinicalTrials.gov to Supplement Information in Ophthalmology Conference Abstracts about Trial Outcomes: A Comparison Study

PubMed Central

Scherer, Roberta W.; Huynh, Lynn; Ervin, Ann-Margret; Dickersin, Kay

2015-01-01

Background Including results from unpublished randomized controlled trials (RCTs) in a systematic review may ameliorate the effect of publication bias in systematic review results. Unpublished RCTs are sometimes described in abstracts presented at conferences, included in trials registers, or both. Trial results may not be available in a trials register and abstracts describing RCT results often lack study design information. Complementary information from a trials register record may be sufficient to allow reliable inclusion of an unpublished RCT only available as an abstract in a systematic review. Methods We identified 496 abstracts describing RCTs presented at the 2007 to 2009 Association for Research in Vision and Ophthalmology (ARVO) meetings; 154 RCTs were registered in ClinicalTrials.gov. Two persons extracted verbatim primary and non-primary outcomes reported in the abstract and ClinicalTrials.gov record. We compared each abstract outcome with all ClinicalTrials.gov outcomes and coded matches as complete, partial, or no match. Results We identified 800 outcomes in 152 abstracts (95 primary [51 abstracts] and 705 [141 abstracts] non-primary outcomes). No outcomes were reported in 2 abstracts. Of 95 primary outcomes, 17 (18%) agreed completely, 53 (56%) partially, and 25 (26%) had no match with a ClinicalTrials.gov primary or non-primary outcome. Among 705 non-primary outcomes, 56 (8%) agreed completely, 205 (29%) agreed partially, and 444 (63%) had no match with a ClinicalTrials.gov primary or non-primary outcome. Among the 258 outcomes partially agreeing, we found additional information on the time when the outcome was measured more often in ClinicalTrials.gov than in the abstract (141/258 (55%) versus 55/258 (21%)). We found no association between the presence of non-matching “new” outcomes and year of registration, time to registry update, industry sponsorship, or multi-center status. Conclusion Conference abstracts may be a valuable source of

Stimulus Responsive Nanoparticles

NASA Technical Reports Server (NTRS)

Sierros, Konstantinos A. (Inventor); Cairns, Darran Robert (Inventor); Huebsch, Wade W. (Inventor); Shafran, Matthew S. (Inventor)

2017-01-01

Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment including a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

Stimulus responsive nanoparticles

NASA Technical Reports Server (NTRS)

Cairns, Darren Robert (Inventor); Shafran, Matthew S. (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor)

2013-01-01

Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

Stimulus Responsive Nanoparticles

NASA Technical Reports Server (NTRS)

Cairns, Darran Robert (Inventor); Huebsch, Wade W. (Inventor); Sierros, Konstantinos A. (Inventor); Shafran, Matthew S. (Inventor)

2015-01-01

Disclosed are various embodiments of methods and systems related to stimulus responsive nanoparticles. In one embodiment includes a stimulus responsive nanoparticle system, the system includes a first electrode, a second electrode, and a plurality of elongated electro-responsive nanoparticles dispersed between the first and second electrodes, the plurality of electro-responsive nanorods configured to respond to an electric field established between the first and second electrodes.

Magnetic nanoparticles to recover cellular organelles and study the time resolved nanoparticle-cell interactome throughout uptake.

PubMed

Bertoli, Filippo; Davies, Gemma-Louise; Monopoli, Marco P; Moloney, Micheal; Gun'ko, Yurii K; Salvati, Anna; Dawson, Kenneth A

2014-08-27

Nanoparticles in contact with cells and living organisms generate quite novel interactions at the interface between the nanoparticle surface and the surrounding biological environment. However, a detailed time resolved molecular level description of the evolving interactions as nanoparticles are internalized and trafficked within the cellular environment is still missing and will certainly be required for the emerging arena of nanoparticle-cell interactions to mature. In this paper promising methodologies to map out the time resolved nanoparticle-cell interactome for nanoparticle uptake are discussed. Thus silica coated magnetite nanoparticles are presented to cells and their magnetic properties used to isolate, in a time resolved manner, the organelles containing the nanoparticles. Characterization of the recovered fractions shows that different cell compartments are isolated at different times, in agreement with imaging results on nanoparticle intracellular location. Subsequently the internalized nanoparticles can be further isolated from the recovered organelles, allowing the study of the most tightly nanoparticle-bound biomolecules, analogous to the 'hard corona' that so far has mostly been characterized in extracellular environments. Preliminary data on the recovered nanoparticles suggest that significant portion of the original corona (derived from the serum in which particles are presented to the cells) is preserved as nanoparticles are trafficked through the cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gold Nanoparticles Cytotoxicity

NASA Astrophysics Data System (ADS)

Mironava, Tatsiana

Over the last two decades gold nanoparticles (AuNPs) have been used for many scientific applications and have attracted attention due to the specific chemical, electronic and optical size dependent properties that make them very promising agents in many fields such as medicine, imagine techniques and electronics. More specifically, biocompatible gold nanoparticles have a huge potential for use as the contrast augmentation agent in X-ray Computed Tomography and Photo Acoustic Tomography for early tumor diagnostic as well these nanoparticles are extensively researched for enhancing the targeted cancer treatment effectiveness such as photo-thermal and radiotherapy. In most biomedical applications biocompatible gold nanoparticles are labeled with specific tumor or other pathology targeting antibodies and used for site specific drug delivery. However, even though gold nanoparticles poses very high level of anti cancer properties, the question of their cytotoxicity ones they are released in normal tissue has to be researched. Moreover, the huge amount of industrially produced gold nanoparticles raises the question of these particles being a health hazard, since the penetration is fairly easy for the "nano" size substances. This study focuses on the effect of AuNPs on a human skin tissue, since it is fall in both categories -- the side effects for biomedical applications and industrial workers and users' exposure during production and handling. Therefore, in the present project, gold nanoparticles stabilized with the biocompatible agent citric acid were generated and characterized by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The cytotoxic effect of AuNPs release to healthy skin tissue was modeled on 3 different cell types: human keratinocytes, human dermal fibroblasts, and human adipose derived stromal (ADS) cells. The AuNPs localization inside the cell was found to be cell type dependent. Overall cytotoxicity was found to be dependent

Deposition of conductive TiN shells on SiO2 nanoparticles with a fluidized bed ALD reactor

NASA Astrophysics Data System (ADS)

Didden, Arjen; Hillebrand, Philipp; Wollgarten, Markus; Dam, Bernard; van de Krol, Roel

2016-02-01

Conductive TiN shells have been deposited on SiO2 nanoparticles (10-20 nm primary particle size) with fluidized bed atomic layer deposition using TDMAT and NH3 as precursors. Analysis of the powders confirms that shell growth saturates at approximately 0.4 nm/cycle at TDMAT doses of >1.2 mmol/g of powder. TEM and XPS analysis showed that all particles were coated with homogeneous shells containing titanium. Due to the large specific surface area of the nanoparticles, the TiN shells rapidly oxidize upon exposure to air. Electrical measurements show that the partially oxidized shells are conducting, with apparent resistivity of approximately 11 kΩ cm. The resistivity of the powders is strongly influenced by the NH3 dose, with a smaller dose giving an order-of-magnitude higher resistivity.

Electronically cloaked nanoparticles

NASA Astrophysics Data System (ADS)

Shen, Wenqing

The concept of electronic cloaking is to design objects invisible to conduction electrons. The approach of electronic cloaking has been recently suggested to design invisible nanoparticle dopants with electronic scattering cross section smaller than 1% of the physical cross section (pi a2), and therefore to enhance the carrier mobility of bulk materials. The proposed nanoparticles have core-shell structures. The dopants are incorporated inside the core, while the shell layer serves both as a spacer to separate the charge carriers from their parent atoms and as a cloaking shell to minimize the scattering cross section of the electrons from the ionized nanoparticles. Thermoelectric materials are usually highly doped to have enough carrier density. Using invisible dopants could achieve larger thermoelectric power factors by enhancing the electronic mobility. Core-shell nanoparticles show an advantage over one-layer nanoparticles, which are proposed in three-dimensional modulation doping. However designing such nanoparticles is not easy as there are too many parameters to be considered. This thesis first shows an approach to design hollow nanoparticles by applying constrains on variables. In the second part, a simple mapping approach is introduced where one can identify possible core-shell particles by comparing the dimensionless parameters of chosen materials with provided maps. In both parts of this work, several designs with realistic materials were made and proven to achieve electronic cloaking. Improvement in the thermoelectric power factor compared to the traditional impurity doping method was demonstrated in several cases.

Shape tunable plasmonic nanoparticles

DOEpatents

El-Sayed, Mostafa A.; El-Sayed, Ivan Homer

2017-03-07

Noble metal nanoparticles and methods of their use are provided. Certain aspects provided solid noble metal nanoparticles tuned to the near infrared. The disclosed nanoparticles can be used in molecular imaging, diagnosis, and treatment. Methods for imaging cells are also provided.

Quantification of nanoparticle endocytosis based on double fluorescent pH-sensitive nanoparticles.

PubMed

Kurtz-Chalot, Andréa; Klein, Jean-Philippe; Pourchez, Jérémie; Boudard, Delphine; Bin, Valérie; Sabido, Odile; Marmuse, Laurence; Cottier, Michèle; Forest, Valérie

2015-04-01

Amorphous silica is a particularly interesting material because of its inertness and chemical stability. Silica nanoparticles have been recently developed for biomedical purposes but their innocuousness must be carefully investigated before clinical use. The relationship between nanoparticles physicochemical features, their uptake by cells and their biological activity represents a crucial issue, especially for the development of nanomedicine. This work aimed at adapting a method for the quantification of nanoparticle endocytosis based on pH-sensitive and double fluorescent particles. For that purpose, silica nanoparticles containing two fluorophores: FITC and pHrodo(TM) were developed, their respective fluorescence emission depends on the external pH. Indeed, FITC emits a green fluorescence at physiological pH and pHrodo(TM) emits a red fluorescence which intensity increased with acidification. Therefore, nanoparticles remained outside the cells could be clearly distinguished from nanoparticles uptaken by cells as these latter could be spotted inside cellular acidic compartments (such as phagolysosomes, micropinosomes…). Using this model, the endocytosis of 60 nm nanoparticles incubated with the RAW 264.7 macrophages was quantified using time-lapse microscopy and compared to that of 130 nm submicronic particles. The amount of internalized particles was also evaluated by fluorimetry. The biological impact of the particles was also investigated in terms of cytotoxicity, pro-inflammatory response and oxidative stress. Results clearly demonstrated that nanoparticles were more uptaken and more reactive than submicronic particles. Moreover, we validated a method of endocytosis quantification.

Durability improvements of two-dimensional metal nanoparticle sheets by molecular cross-linked structures between nanoparticles

NASA Astrophysics Data System (ADS)

Saito, Noboru; Ryuzaki, Sou; Wang, Pangpang; Park, Susie; Sakai, Nobuyuki; Tatsuma, Tetsu; Okamoto, Koichi; Tamada, Kaoru

2018-03-01

The durability of two-dimensional metal nanoparticle sheets is a crucial factor for realizing next-generation optoelectronic devices based on plasmonics such as organic light-emitting diodes. Here, we report improvements in the durability of Ag nanoparticle sheets by forming alkanedithiol (DT16) cross-linked structures between the nanoparticles. The cross-linked structures in a sheet were fabricated by the self-assembly of DT16-capped Ag nanoparticles with 10% coverage (AgDT16). The durabilities for thermal, organic solvent, and oxidation reactions of AgDT16 sheets were found to be improved owing to the cross-linked structures by comparing Ag nanoparticle sheets without the cross-linked structures. The absorbance spectra revealed that the Ag nanoparticle sheets without the structure are markedly damaged by each durability test, whereas the AgDT16 sheets remain. The molecular cross-linked structures between nanoparticles in two-dimansional metal nanoparticle sheets were found to have the potential to play a key role in the realization of plasmonic optoelectronic devices including metal nanoparticles.

Ethics in the computer age. Conference proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kizza, J.M.

1994-12-31

These proceedings contain the papers presented at the Ethics in the Computer Age conference held in Gatlinburg, Tennessee, November 11-13, 1994. The conference was sponsored by ACM SIGCAS (Computers and Society) to which I am very grateful. The Ethics in the Computer Age conference sequence started in 1991 with the first conference at the campus of the University of Tennessee at Chattanooga. The second was help at the same location a year later. These two conferences were limited to only invited speakers, but their success was overwhelming. This is the third in the sequence and the first truly international one.more » Plans are already under way for the fourth in 1996.« less

EPOXI Mission Press Conference

NASA Image and Video Library

2010-11-18

Dr. James Green, Director of Planetary Science, NASA Headquarters, at podium, speaks during a press conference, Thursday, Nov. 18, 2010, at NASA Headquarters in Washington. The press conference was held to discuss the Nov. 4 successful flyby of Comet Hartley 2 by NASA's EPOXI Mission Spacecraft. Images from the flyby provided scientists the most extensive observations of a comet in history. Photo Credit: (NASA/Paul E. Alers)

EPOXI Mission Press Conference

NASA Image and Video Library

2010-11-18

Pete Schultz, EPOXI scientist from Brown University, makes a point during a press conference, Thursday, Nov. 18, 2010, at NASA Headquarters in Washington. The press conference was held to discuss the Nov. 4 successful flyby of Comet Hartley 2 by NASA's EPOXI Mission Spacecraft. Images from the flyby provided scientists the most extensive observations of a comet in history. Photo Credit: (NASA/Paul E. Alers)

3rd Annual PIALA Conference Saipan--Collecting, Preserving & Sharing Information in Micronesia. Conference Proceedings. October 13-15, 1993.

ERIC Educational Resources Information Center

Edmundson, Margaret, Ed.

1993-01-01

This PIALA 1993 Proceedings contains many of the papers presented at the 3rd annual conference of the Pacific Islands Association of Libraries and Archives. This publication is the first time papers from this Micronesian regional library and archives conference have ever been published. The conference addressed various topics of interest to…

NDE Conference on Civil Engineering : a joint conference of the 7th Structural Materials Technology Conference (SMT) and the 6th International Symposium on Nondestructive Testing in Civil Engineering (NDT-CE)

DOT National Transportation Integrated Search

2007-01-01

The 2006 NDE conference on Civil Engineering was held in St. Louis, MO on August 14 18, 2006. The conference combined the 7th Structural Materials Technology Conference (SMT) along with the 6th International Symposium on Nondestructive Testing in...

Disturbances and Contradictions in an Online Conference

ERIC Educational Resources Information Center

Carr, Tony; Ludvigsen, Sten Runar

2017-01-01

This article analyses participant experiences and statements about perceived problems in two online conferences to identify tensions and disturbances relating to external factors, conference technology, online discussions and design choices and then considers the underlying contradictions within the conference systems which generate both positive…

Polymeric nanoparticles

PubMed Central

Bolhassani, Azam; Javanzad, Shabnam; Saleh, Tayebeh; Hashemi, Mehrdad; Aghasadeghi, Mohammad Reza; Sadat, Seyed Mehdi

2014-01-01

Nanocarriers with various compositions and biological properties have been extensively applied for in vitro/in vivo drug and gene delivery. The family of nanocarriers includes polymeric nanoparticles, lipid-based carriers (liposomes/micelles), dendrimers, carbon nanotubes, and gold nanoparticles (nanoshells/nanocages). Among different delivery systems, polymeric carriers have several properties such as: easy to synthesize, inexpensive, biocompatible, biodegradable, non-immunogenic, non-toxic, and water soluble. In addition, cationic polymers seem to produce more stable complexes led to a more protection during cellular trafficking than cationic lipids. Nanoparticles often show significant adjuvant effects in vaccine delivery since they may be easily taken up by antigen presenting cells (APCs). Natural polymers such as polysaccharides and synthetic polymers have demonstrated great potential to form vaccine nanoparticles. The development of new adjuvants or delivery systems for DNA and protein immunization is an expanding research field. This review describes polymeric carriers especially PLGA, chitosan, and PEI as vaccine delivery systems. PMID:24128651

PREFACE: Nuclear Cluster Conference; Cluster'07

NASA Astrophysics Data System (ADS)

Freer, Martin

2008-05-01

The Cluster Conference is a long-running conference series dating back to the 1960's, the first being initiated by Wildermuth in Bochum, Germany, in 1969. The most recent meeting was held in Nara, Japan, in 2003, and in 2007 the 9th Cluster Conference was held in Stratford-upon-Avon, UK. As the name suggests the town of Stratford lies upon the River Avon, and shortly before the conference, due to unprecedented rainfall in the area (approximately 10 cm within half a day), lay in the River Avon! Stratford is the birthplace of the `Bard of Avon' William Shakespeare, and this formed an intriguing conference backdrop. The meeting was attended by some 90 delegates and the programme contained 65 70 oral presentations, and was opened by a historical perspective presented by Professor Brink (Oxford) and closed by Professor Horiuchi (RCNP) with an overview of the conference and future perspectives. In between, the conference covered aspects of clustering in exotic nuclei (both neutron and proton-rich), molecular structures in which valence neutrons are exchanged between cluster cores, condensates in nuclei, neutron-clusters, superheavy nuclei, clusters in nuclear astrophysical processes and exotic cluster decays such as 2p and ternary cluster decay. The field of nuclear clustering has become strongly influenced by the physics of radioactive beam facilities (reflected in the programme), and by the excitement that clustering may have an important impact on the structure of nuclei at the neutron drip-line. It was clear that since Nara the field had progressed substantially and that new themes had emerged and others had crystallized. Two particular topics resonated strongly condensates and nuclear molecules. These topics are thus likely to be central in the next cluster conference which will be held in 2011 in the Hungarian city of Debrechen. Martin Freer Participants and Cluster'07

20 CFR 901.34 - Conferences.

Code of Federal Regulations, 2013 CFR

2013-04-01

...' Benefits JOINT BOARD FOR THE ENROLLMENT OF ACTUARIES REGULATIONS GOVERNING THE PERFORMANCE OF ACTUARIAL... § 901.34 Conferences. (a) In general. The Executive Director may confer with an enrolled actuary... of the actuary or the Executive Director. (b) Voluntary suspension or termination of enrollment. An...

20 CFR 901.34 - Conferences.

Code of Federal Regulations, 2014 CFR

2014-04-01

...' Benefits JOINT BOARD FOR THE ENROLLMENT OF ACTUARIES REGULATIONS GOVERNING THE PERFORMANCE OF ACTUARIAL... § 901.34 Conferences. (a) In general. The Executive Director may confer with an enrolled actuary... of the actuary or the Executive Director. (b) Voluntary suspension or termination of enrollment. An...

20 CFR 901.34 - Conferences.

Code of Federal Regulations, 2011 CFR

2011-04-01

...' Benefits JOINT BOARD FOR THE ENROLLMENT OF ACTUARIES REGULATIONS GOVERNING THE PERFORMANCE OF ACTUARIAL... § 901.34 Conferences. (a) In general. The Executive Director may confer with an enrolled actuary... of the actuary or the Executive Director. (b) Voluntary suspension or termination of enrollment. An...

20 CFR 901.34 - Conferences.

Code of Federal Regulations, 2012 CFR

2012-04-01

...' Benefits JOINT BOARD FOR THE ENROLLMENT OF ACTUARIES REGULATIONS GOVERNING THE PERFORMANCE OF ACTUARIAL... § 901.34 Conferences. (a) In general. The Executive Director may confer with an enrolled actuary... of the actuary or the Executive Director. (b) Voluntary suspension or termination of enrollment. An...

20 CFR 901.34 - Conferences.

Code of Federal Regulations, 2010 CFR

2010-04-01

...' Benefits JOINT BOARD FOR THE ENROLLMENT OF ACTUARIES REGULATIONS GOVERNING THE PERFORMANCE OF ACTUARIAL... § 901.34 Conferences. (a) In general. The Executive Director may confer with an enrolled actuary... of the actuary or the Executive Director. (b) Voluntary suspension or termination of enrollment. An...

DOE Workshop at Tapia Conference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Valerie

2015-02-19

The DE-SC0013568 DOE Grant, in the amount of $11,822.79, was used to support five doctoral students from underrepresented groups to attend the 2015 Richard Tapia Celebration of Diversity in Computing Conference, held February 18-21 in Boston, MA. Each scholarship was approximately $1200 to cover conference registration, travel, and lodging for the duration of the conference. The remaining $5,822.79 was used to support a DOE Breakfast Workshop during breakfast on Thursday, February 19. The Breakfast supported approximately 140 graduate students from underrepresented groups to learn about the different career opportunities at the different DOE National Laboratories.

The feasibility of using magnetic nanoparticles modified as gene vector.

PubMed

Chen, D; Tang, Q; Xue, W; Wang, X

2010-06-01

To evaluate the feasibility of using magnetic nanoparticles (MNPs) as gene vector and the effect of magnetic field on efficiency of transfection. Magnetic nanoparticles were prepared by controlling some chemical reaction parameters through a partially reduction precipitation method with ferric chloride aqueous solution as precursor material. The surface of particles was modified by polyethyleneimine (PEI) agents. The appearance, the size distribution, structure and phase constitute of MNPs were characterized by Transmission electron microscope (TEM), X-ray diffraction (XRD); the potential of absorbing DNA of MNPs was analysed by electrophoresis. Transfection was determined by delivering reporter gene, PGL2-control encoding luciferase, to different cell lines using MNPs-PLL as vector. The effect of magnetic field on the efficiency of transfection was determined using Nd-Fe-B permanent magnet. Foreign gene could be delivered to various cell lines by MNPs-PLL and expressed with high efficiency but the transfection efficiency and time course varied in the different cell lines studied. Magnetic field could enhance the efficiency of transfection by 5-10 fold. MNPs- PLL can be used as a novel non-viral gene vector in vitro, which offers a basis for gene delivery in vivo.

The effects of bacteria-nanoparticles interface on the antibacterial activity of green synthesized silver nanoparticles.

PubMed

Ahmad, Aftab; Wei, Yun; Syed, Fatima; Tahir, Kamran; Rehman, Aziz Ur; Khan, Arifullah; Ullah, Sadeeq; Yuan, Qipeng

2017-01-01

Neutralization of bacterial cell surface potential using nanoscale materials is an effective strategy to alter membrane permeability, cytoplasmic leakage, and ultimate cell death. In the present study, an attempt was made to prepare biogenic silver nanoparticles using biomolecules from the aqueous rhizome extract of Coptis Chinensis. The biosynthesized silver nanoparticles were surface modified with chitosan biopolymer. The prepared silver nanoparticles and chitosan modified silver nanoparticles were cubic crystalline structures (XRD) with an average particle size of 15 and 20 nm respectively (TEM, DLS). The biosynthesized silver nanoparticles were surface stabilized by polyphenolic compounds (FTIR). Coptis Chinensis mediated silver nanoparticles displayed significant activity against E. coli and Bacillus subtilus with a zone of inhibition 12 ± 1.2 (MIC = 25 μg/mL) and 18 ± 1.6 mm (MIC = 12.50 μg/mL) respectively. The bactericidal efficacy of these nanoparticles was considerably increased upon surface modification with chitosan biopolymer. The chitosan modified biogenic silver nanoparticles exhibited promising activity against E. coli (MIC = 6.25 μg/mL) and Bacillus subtilus (MIC = 12.50 μg/mL). Our results indicated that the chitosan modified silver nanoparticles were promising agents in damaging bacterial membrane potential and induction of high level of intracellular reactive oxygen species (ROS). In addition, these nanoparticles were observed to induce the release of the high level of cytoplasmic materials especially protein and nucleic acids into the media. All these findings suggest that the chitosan functionalized silver nanoparticles are efficient agents in disrupting bacterial membrane and induction of ROS leading to cytoplasmic leakage and cell death. These findings further conclude that the bacterial-nanoparticles surface potential modulation is an effective strategy in enhancing the antibacterial potency of silver nanoparticles

NIH Consensus Conference. Acupuncture.

PubMed

1998-11-04

To provide clinicians, patients, and the general public with a responsible assessment of the use and effectiveness of acupuncture to treat a variety of conditions. A nonfederal, nonadvocate, 12-member panel representing the fields of acupuncture, pain, psychology, psychiatry, physical medicine and rehabilitation, drug abuse, family practice, internal medicine, health policy, epidemiology, statistics, physiology, biophysics, and the representatives of the public. In addition, 25 experts from these same fields presented data to the panel and a conference audience of 1200. Presentations and discussions were divided into 3 phases over 2 1/2 days: (1) presentations by investigators working in areas relevant to the consensus questions during a 2-day public session; (2) questions and statements from conference attendees during open discussion periods that were part of the public session; and (3) closed deliberations by the panel during the remainder of the second day and morning of the third. The conference was organized and supported by the Office of Alternative Medicine and the Office of Medical Applications of Research, National Institutes of Health, Bethesda, Md. The literature, produced from January 1970 to October 1997, was searched through MEDLINE, Allied and Alternative Medicine, EMBASE, and MANTIS, as well as through a hand search of 9 journals that were not indexed by the National Library of Medicine. An extensive bibliography of 2302 references was provided to the panel and the conference audience. Expert speakers prepared abstracts of their own conference presentations with relevant citations from the literature. Scientific evidence was given precedence over clinical anecdotal experience. The panel, answering predefined questions, developed their conclusions based on the scientific evidence presented in the open forum and scientific literature. The panel composed a draft statement, which was read in its entirety and circulated to the experts and the audience

The effect of coating on heat generation properties of Iron oxide nanoparticles

NASA Astrophysics Data System (ADS)

Yuan, Yuan

on magnetic properties and heat generation rate of magnetic nanoparticles was investigated by comparing the experimental and predicted SAR. For this purpose, AC magnetic susceptibility of suspensions was measured and also calculated by Debye model. Both were used to predict SAR and then compare it to the measured SAR. Poor agreement was found when the predictions were based on the Debye model, which neglects dipolar interactions between nanoparticles within aggregations. For uncoated and amine-functionalized particles (with aggregations) experimental SAR was found to agree relatively well with predicted SAR using experimental susceptibility values, which is expected to capture magnetic losses. For biotin and protein A coated nanoparticles (both having large, asymmetric clusters), the experimental SAR of both samples was found to be higher than the SAR predicted with experimental susceptibility. This unexpected discrepancy was attributed in part to friction loss associated with the partial rotation of clusters. This hypothesis was confirmed by examining the temperature increasing rate of particles embeded in hydrogel with different stiffness. At last, the properties of magnetic nanoparticles dispersed in DI water, Neurobasal (NB), or astrocyte culture media were studied. The aminosilane coated nanoparticles that dispersed in astrocyte culture media presented highest susceptibility and SAR compared to that suspended in DI water or NB, which was attributed to its highest aggregation size and magnetization phase concentration. However, for starch coated nanoparticles, samples prepared in either media showed similar magnetic and heating properties. The cell studies started with investigation of the response of primary cortical neurons to magnetite nanoparticles with aminosilane, starch and polydimethylamine coatings. It was found that polydimethylamine functionalized nanoparticles induce cell death at all concentrations and complete removal of plasma membrane. Aminosilane

Effects of Partial and Acute Total Sleep Deprivation on Performance across Cognitive Domains, Individuals and Circadian Phase

PubMed Central

Lo, June C.; Groeger, John A.; Santhi, Nayantara; Arbon, Emma L.; Lazar, Alpar S.; Hasan, Sibah; von Schantz, Malcolm; Archer, Simon N.; Dijk, Derk-Jan

2012-01-01

Background Cognitive performance deteriorates during extended wakefulness and circadian phase misalignment, and some individuals are more affected than others. Whether performance is affected similarly across cognitive domains, or whether cognitive processes involving Executive Functions are more sensitive to sleep and circadian misalignment than Alertness and Sustained Attention, is a matter of debate. Methodology/Principal Findings We conducted a 2 × 12-day laboratory protocol to characterize the interaction of repeated partial and acute total sleep deprivation and circadian phase on performance across seven cognitive domains in 36 individuals (18 males; mean ± SD of age = 27.6±4.0 years). The sample was stratified for the rs57875989 polymorphism in PER3, which confers cognitive susceptibility to total sleep deprivation. We observed a deterioration of performance during both repeated partial and acute total sleep deprivation. Furthermore, prior partial sleep deprivation led to poorer cognitive performance in a subsequent total sleep deprivation period, but its effect was modulated by circadian phase such that it was virtually absent in the evening wake maintenance zone, and most prominent during early morning hours. A significant effect of PER3 genotype was observed for Subjective Alertness during partial sleep deprivation and on n-back tasks with a high executive load when assessed in the morning hours during total sleep deprivation after partial sleep loss. Overall, however, Subjective Alertness and Sustained Attention were more affected by both partial and total sleep deprivation than other cognitive domains and tasks including n-back tasks of Working Memory, even when implemented with a high executive load. Conclusions/Significance Sleep loss has a primary effect on Sleepiness and Sustained Attention with much smaller effects on challenging Working Memory tasks. These findings have implications for understanding how sleep debt and circadian rhythmicity

Selecting a Good Conference Location Based on Participants' Interests

ERIC Educational Resources Information Center

Miah, Muhammed

2011-01-01

Selecting a good conference location within budget constraints to attract paper authors and participants is a very difficult job for the conference organizers. A conference location is also very important along with other issues such as ranking of the conference. Selecting a bad conference location may reduce the number of paper submissions and…

Experiences Sustaining a Conference and Building a Network

ERIC Educational Resources Information Center

Grady, Marilyn L.

2016-01-01

The Women in Educational Leadership Conference (WELC) was founded at the University of Nebraska-Lincoln in 1987. The 28th conference was held in October 2014. A database related to the conference has been maintained throughout these years. Using these data, the following report includes the factors that have sustained the conference, the network…

Enhancement of algicidal properties of immobilized Bacillus methylotrophicus ZJU by coating with magnetic Fe₃O₄ nanoparticles and wheat bran.

PubMed

Sun, Pengfei; Hui, Cai; Wang, Sheng; Khan, Rashid Azim; Zhang, Qichun; Zhao, Yu-Hua

2016-01-15

Algicidal bacteria offer a promising option for killing cyanobacteria. In this study, a newly isolated strain of Bacillus methylotrophicus, ZJU, was used to control Microcystis aeruginosa. Analyses of relative reactive oxygen level, malondialdehyde content, superoxide dismutase activity, and fluorescence staining indicated that oxidative damage caused by the algicidal supernatant of strain ZJU mainly affected the cell membrane and consequently the membrane permeability and membrane potential of M. aeruginosa cells. Furthermore, an embedded immobilization technique was employed to improve the practical application of strain ZJU as an algicidal agent. On this basis, we proposed a novel concept of enhancing the algicidal properties of immobilized ZJU by adding Fe3O4 nanoparticles and wheat bran in the process of immobilization. Our studies showed that Fe3O4 nanoparticles conferred the immobilized bacteria with a magnetization of 30.87 emu/g, and this magnetization enabled efficient re-collection of the immobilized bacteria by magnetic means. Moreover, wheat bran endowed the immobilized bacteria with 10.34% higher algicidal activity than immobilized bacteria without wheat bran. The results indicate a novel concept of enhancing the algicidal property of bacteria against M. aeruginosa by adding Fe3O4 nanoparticles and wheat bran. Copyright © 2015 Elsevier B.V. All rights reserved.

Dirhenium decacarbonyl-loaded PLLA nanoparticles: influence of neutron irradiation and preliminary in vivo administration by the TMT technique.

PubMed

Hamoudeh, Misara; Fessi, Hatem; Mehier, Henri; Faraj, Achraf Al; Canet-Soulas, Emmanuelle

2008-02-04

In a previous study, we have described the elaboration of PLLA-based nanoparticles loaded with non radioactive dirhenium decacarbonyl [Re(2)(CO)(10)], a novel neutron-activatable radiopharmaceutical dosage form for intra-tumoral radiotherapy. These nanoparticles are designed for a neutron irradiation which can be carried out in a nuclear reactor facility. This new paper describes the neutron irradiation influence on these Re(2)(CO)(10)-loaded PLLA nanoparticles. The loaded nanoparticles with 23% (w/w) of metallic rhenium have shown to remain stable and separated and to keep out their sphericity at the lower neutron flux (1x10(11)n/cm(2)/s for 0.5h) which was used for rhenium content determination (neutron activation analysis, NAA). However, when loaded nanoparticles were irradiated at the higher neutron flux (1.45x10(13)n/cm(2)/s, 1h), they have shown to be partially coagglomerated and some pores appeared at their surface. Furthermore, DSC results showed a decrease in the PLLA melting point and melting enthalpy in both blank and loaded nanoparticles indicating a decrease in polymer crystallinity. In addition, the polymer molecular weights (M(n), M(w)) decreased after irradiation but without largely affecting the polymer polydispersity index (P.I.) which indicated that an irradiation-induced PLLA chain scission had occurred in a random way. The XRD patterns of irradiated PLLA provided another proof of polymer loss of crystallinity. FTIR spectra results have shown that irradiated nanoparticles retained the chemical identity of the used Re(2)(CO)(10) and PLLA despite the reduction in polymer crystallinity and molecular weight. Nanoparticles suspending after irradiation became also more difficult, but it was properly achievable by adding PVA (1%) and ethanol (10%) into the dispersing medium. Moreover, after 24h incubation of different irradiated nanoparticles in two different culture mediums, visual examination did not show bacterial growth indicating that applied

Minority University-Space Interdisciplinary Network Conference Proceedings of the Seventh Annual Users' Conference

NASA Technical Reports Server (NTRS)

Harrington, James L., Jr.; Brown, Robin L.; Shukla, Pooja

1998-01-01

Seventh annual conference proceedings of the Minority University-SPace Interdisciplinary Network (MU-SPIN) conference. MU-SPIN is cosponsored by NASA Goddard Space Flight Center and the National Science Foundation, and is a comprehensive educational initiative for Historically Black Colleges and Universities, and minority universities. MU-SPIN focuses on the transfer of advanced computer networking technologies to these institutions and their use for supporting multidisciplinary research.

The Solanum tuberosum KST1 partial promoter as a tool for guard cell expression in multiple plant species.

PubMed

Kelly, Gilor; Lugassi, Nitsan; Belausov, Eduard; Wolf, Dalia; Khamaisi, Belal; Brandsma, Danja; Kottapalli, Jayaram; Fidel, Lena; Ben-Zvi, Batsheva; Egbaria, Aiman; Acheampong, Atiako Kwame; Zheng, Chuanlin; Or, Etti; Distelfeld, Assaf; David-Schwartz, Rakefet; Carmi, Nir; Granot, David

2017-05-17

To date, guard cell promoters have been examined in only a few species, primarily annual dicots. A partial segment of the potato (Solanum tuberosum) KST1 promoter (KST1 partial promoter, KST1ppro) has previously been shown to confer guard cell expression in potato, tomato (Solanum lycopersicum), citrus [Troyer citrange (C. sinensis×Poncirus trifoliata)], and Arabidopsis (Arabidopsis thaliana). Here, we describe an extensive analysis of the expression pattern of KST1ppro in eight (previously reported, as well as new) species from five different angiosperm families, including the Solanaceae and the Cucurbitaceae, Arabidopsis, the monocot barley (Hordeum vulgare), and two perennial species: grapevine (Vitis vinifera) and citrus. Using confocal imaging and three-dimensional movies, we demonstrate that KST1ppro drives guard cell expression in all of these species, making it the first dicot-originated guard cell promoter shown to be active in a monocot and the first promoter reported to confer guard cell expression in barley and cucumber (Cucumis sativus). The results presented here indicate that KST1ppro can be used to drive constitutive guard cell expression in monocots and dicots and in both annual and perennial plants. In addition, we show that the KST1ppro is active in guard cells shortly after the symmetric division of the guard mother cell and generates stable expression in mature guard cells. This allows us to follow the spatial and temporal distribution of stomata in cotyledons and true leaves. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Conference Connections: Rewiring the Circuit

ERIC Educational Resources Information Center

Siemens, George; Tittenberger, Peter; Anderson, Terry

2008-01-01

Increased openness, two-way dialogue, and blurred distinctions between experts and amateurs have combined with numerous technology tools for dialogue, personal expression, networking, and community formation to "remake" conferences, influencing not only how attendees participate in but also how organizers host conferences today. (Contains 31…

Beating the Futures Conference Game.

ERIC Educational Resources Information Center

Simmonds, W. H. Clive

1983-01-01

Conference survival tips include: (1) noting the different kinds of speakers, their strengths and weaknesses; (2) discovering the reasons for often apparent cross-talk and misunderstanding; and (3) using the concept of futuring to gain ideas as to what can be done after the conference ends. (RM)

Teacher Centering: A National Institute. Conference Report.

ERIC Educational Resources Information Center

Tague, Linda Clark, Ed.; And Others

This report is organized around six chapters: (1) "How This Institute Came About"; (2) "Agenda"; (3) "Teacher Centering in 1976: The Real Experience"; (4) "Description of Teacher Centers"; (5) "Conference Reactions"; and (6) "Conference Directory of Participants." The first chapter discusses the sponsors, and organizers of the conference. Chapter…

Women's Participation in Academic Conferences in Israel

ERIC Educational Resources Information Center

Eden, Devorah

2016-01-01

This article examines the participation of women in academic conferences in Israel, a country in which women are under-represented in academia vertically and horizontally. Data were retrieved from announcements of academic conferences in Israel, for one academic year, covering 56 conferences that attracted 997 participants. Participation was…

Nanoparticles and direct immunosuppression

PubMed Central

Ngobili, Terrika A

2016-01-01

Targeting the immune system with nanomaterials is an intensely active area of research. Specifically, the capability to induce immunosuppression is a promising complement for drug delivery and regenerative medicine therapies. Many novel strategies for immunosuppression rely on nanoparticles as delivery vehicles for small-molecule immunosuppressive compounds. As a consequence, efforts in understanding the mechanisms in which nanoparticles directly interact with the immune system have been overshadowed. The immunological activity of nanoparticles is dependent on the physiochemical properties of the nanoparticles and its subsequent cellular internalization. As the underlying factors for these reactions are elucidated, more nanoparticles may be engineered and evaluated for inducing immunosuppression and complementing immunosuppressive drugs. This review will briefly summarize the state-of-the-art and developments in understanding how nanoparticles induce immunosuppressive responses, compare the inherent properties of nanomaterials which induce these immunological reactions, and comment on the potential for using nanomaterials to modulate and control the immune system. PMID:27229901

10. international mouse genome conference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meisler, M.H.

Ten years after hosting the First International Mammalian Genome Conference in Paris in 1986, Dr. Jean-Louis Guenet presided over the Tenth Conference at the Pasteur Institute, October 7--10, 1996. The 1986 conference was a satellite to the Human Gene Mapping Workshop and had approximately 50 attendees. The 1996 meeting was attended by 300 scientists from around the world. In the interim, the number of mapped loci in the mouse increased from 1,000 to over 20,000. This report contains a listing of the program and its participants, and two articles that review the meeting and the role of the laboratory mousemore » in the Human Genome project. More than 200 papers were presented at the conference covering the following topics: International mouse chromosome committee meetings; Mutant generation and identification; Physical and genetic maps; New technology and resources; Chromatin structure and gene regulation; Rate and hamster genetic maps; Informatics and databases; and Quantitative trait analysis.« less

Conferring in the CAFÉ: One-to-One Reading Conferences in Two First Grade Classrooms

ERIC Educational Resources Information Center

Pletcher, Bethanie; Christensen, Rosalynn

2017-01-01

The purpose of this qualitative descriptive case study was to explore the teacher/student reading conferences in two first grade teachers' classrooms in one primary school. Sixteen one-to-one reading conferences were recorded and transcribed over a two-month period and coded for content as related to the CAFÉ (Boushey & Moser, 2009) model of…

Engineered polymeric nanoparticles for soil remediation.

PubMed

Tungittiplakorn, Warapong; Lion, Leonard W; Cohen, Claude; Kim, Ju-Young

2004-03-01

Hydrophobic organic groundwater contaminants, such as polynuclear aromatic hydrocarbons (PAHs), sorb strongly to soils and are difficult to remove. We report here on the synthesis of amphiphilic polyurethane (APU) nanoparticles for use in remediation of soil contaminated with PAHs. The particles are made of polyurethane acrylate anionomer (UAA) or poly(ethylene glycol)-modified urethane acrylate (PMUA) precursor chains that can be emulsified and cross-linked in water. The resulting particles are of colloidal size (17-97 nm as measured by dynamic light scattering). APU particles have the ability to enhance PAH desorption and transport in a manner comparable to that of surfactant micelles, but unlike the surface-active components of micelles, the individual cross-linked precursor chains in APU particles are not free to sorb to the soil surface. Thus, the APU particles are stable independent of their concentration in the aqueous phase. In this paper we show that APU particles can be engineered to achieve desired properties. Our experimental results show that the APU particles can be designed to have hydrophobic interior regions that confer a high affinity for phenanthrene (PHEN) and hydrophilic surfaces that promote particle mobility in soil. The affinity of APU particles for contaminants such as PHEN can be controlled by changing the size of the hydrophobic segment used in the chain synthesis. The mobility of colloidal APU suspensions in soil is controlled by the charge density or the size of the pendent water-soluble chains that reside on the particle surface. Exemplary results are provided illustrating the influence of alternative APU particle formulations with respect to their efficacy for contaminant removal. The ability to control particle properties offers the potential to produce different nanoparticles optimized for varying contaminant types and soil conditions.

Bellagio conference and book. Symbiosis as Source of Evolutionary Innovation: Speciation and Morphogenesis. Conference--June 25-30, 1989, Bellagio Conference Center, Italy

NASA Technical Reports Server (NTRS)

Margulis, L.; Fester, R.

1991-01-01

This conference at the Bellagio Conference Center, Italy, from June 25-30, 1989, provided a unique opportunity for evolutionary theorists and symbiosis biologists to cross the boundaries of their respective disciplines and share ideas. A major task was to address the adequacy of the prevailing neodarwinian concept of evolution with respect to the relative importance of symbiosis in the origin of morphological and evolutionary novelty.

EPOXI Mission Press Conference

NASA Image and Video Library

2010-11-18

Tim Larson, EPOXI Project Manager from the Jet Propulsion Laboratory in Pasadena, Calif., speaks during a press conference, Thursday, Nov. 18, 2010, at NASA Headquarters in Washington. The press conference was held to discuss the Nov. 4 successful flyby of Comet Hartley 2 by NASA's EPOXI Mission Spacecraft. Images from the flyby provided scientists the most extensive observations of a comet in history. Photo Credit: (NASA/Paul E. Alers)

National Small Business Conference

DTIC Science & Technology

2005-06-02

Untitled Document 2005 National Small Business Conference.html[8/30/2016 1:07:10 PM] National Small Business Conference “Opening New Frontiers...Through Effective Partnering” Los Angeles, CA 31 May - 2 June 2005 AGENDA Wednesday, 23 March 2005 Small Business and the Defense Industrial Base, Mr...Frank Ramos, Director, Office of Small and Disadvantaged Business Utilization, DoD The Hill: How It Can Help Your Small Business , Mr. Ron Perlman

Partial (focal) seizure

MedlinePlus

... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff ... Practice . 7th ed. Philadelphia, PA: Elsevier; 2016:chap 101. ...

EDITORIAL: International MEMS Conference 2006

NASA Astrophysics Data System (ADS)

Tay, Francis E. H.; Jianmin, Miao; Iliescu, Ciprian

2006-04-01

The International MEMS conference (iMEMS2006) organized by the Institute of Bioengineering and Nanotechnology and Nanyang Technological University aims to provide a platform for academicians, professionals and industrialists in various related fields from all over the world to share and learn from each other. Of great interest is the incorporation of the theme of life sciences application using MEMS. It is the desire of this conference to initiate collaboration and form network of cooperation. This has continued to be the objective of iMEMS since its inception in 1997. The technological advance of MEMS over the past few decades has been truly exciting in terms of development and applications. In order to participate in this rapid development, a conference involving delegates from within the MEMS community and outside the community is very meaningful and timely. With the receipt of over 200 articles, delegates related to MEMS field from all over the world will share their perspectives on topics such as MEMS/MST Design, MEMS Teaching and Education, MEMS/MST Packaging, MEMS/MST Fabrication, Microsystems Applications, System Integration, Wearable Devices, MEMSWear and BioMEMS. Invited speakers and delegates from outside the field have also been involved to provide challenges, especially in the life sciences field, for the MEMS community to potentially address. The proceedings of the conference will be published as an issue in the online Journal of Physics: Conference Series and this can reach a wider audience and will facilitate the reference and citation of the work presented in the conference. We wish to express our deep gratitude to the International Scientific Committee members and the organizing committee members for contributing to the success of this conference. We would like to thank all the delegates, speakers and sponsors from all over the world for presenting and sharing their perspectives on topics related to MEMS and the challenges that MEMS can

Comparing highly ordered monolayers of nanoparticles fabricated using electrophoretic deposition: Cobalt ferrite nanoparticles versus iron oxide nanoparticles

DOE PAGES

Dickerson, James H.; Krejci, Alex J.; Garcia, Adriana -Mendoza; ...

2015-08-01

Ordered assemblies of nanoparticles remain challenging to fabricate, yet could open the door to many potential applications of nanomaterials. Here, we demonstrate that locally ordered arrays of nanoparticles, using electrophoretic deposition, can be extended to produce long-range order among the constituents. Voronoi tessellations along with multiple statistical analyses show dramatic increases in order compared with previously reported assemblies formed through electric field-assisted assembly. As a result, based on subsequent physical measurements of the nanoparticles and the deposition system, the underlying mechanisms that generate increased order are inferred.

Industrial applications of nanoparticles.

PubMed

Stark, W J; Stoessel, P R; Wohlleben, W; Hafner, A

2015-08-21

Research efforts in the past two decades have resulted in thousands of potential application areas for nanoparticles - which materials have become industrially relevant? Where are sustainable applications of nanoparticles replacing traditional processing and materials? This tutorial review starts with a brief analysis on what makes nanoparticles attractive to chemical product design. The article highlights established industrial applications of nanoparticles and then moves to rapidly emerging applications in the chemical industry and discusses future research directions. Contributions from large companies, academia and high-tech start-ups are used to elucidate where academic nanoparticle research has revolutionized industry practice. A nanomaterial-focused analysis discusses new trends, such as particles with an identity, and the influence of modern instrument advances in the development of novel industrial products.

10 CFR 590.311 - Conferences.