Direct observation and analysis of york-shell materials using low-voltage high-resolution scanning electron microscopy: Nanometal-particles encapsulated in metal-oxide, carbon, and polymer

NASA Astrophysics Data System (ADS)

Asahina, Shunsuke; Suga, Mitsuo; Takahashi, Hideyuki; Young Jeong, Hu; Galeano, Carolina; Schüth, Ferdi; Terasaki, Osamu

2014-11-01

Nanometal particles show characteristic features in chemical and physical properties depending on their sizes and shapes. For keeping and further enhancing their features, the particles should be protected from coalescence or degradation. One approach is to encapsulate the nanometal particles inside pores with chemically inert or functional materials, such as carbon, polymer, and metal oxides, which contain mesopores to allow permeation of only chemicals not the nanometal particles. Recently developed low-voltage high-resolution scanning electron microscopy was applied to the study of structural, chemical, and electron state of both nanometal particles and encapsulating materials in yolk-shell materials of Au@C, Ru/Pt@C, Au@TiO2, and Pt@Polymer. Progresses in the following categories were shown for the yolk-shell materials: (i) resolution of topographic image contrast by secondary electrons, of atomic-number contrast by back-scattered electrons, and of elemental mapping by X-ray energy dispersive spectroscopy; (ii) sample preparation for observing internal structures; and (iii) X-ray spectroscopy such as soft X-ray emission spectroscopy. Transmission electron microscopy was also used for characterization of Au@C.

Computational evaluation of sub-nanometer cluster activity of singly exposed copper atom with various coordinative environment in catalytic CO2 transformation

NASA Astrophysics Data System (ADS)

Shanmugam, Ramasamy; Thamaraichelvan, Arunachalam; Ganesan, Tharumeya Kuppusamy; Viswanathan, Balasubramanian

2017-02-01

Metal cluster, at sub-nanometer level has a unique property in the activation of small molecules, in contrast to that of bulk surface. In the present work, singly exposed active site of copper metal cluster at sub-nanometer level was designed to arrive at the energy minimised configurations, binding energy, electrostatic potential map, frontier molecular orbitals and partial density of states. The ab initio molecular dynamics was carried out to probe the catalytic nature of the cluster. Further, the stability of the metal cluster and its catalytic activity in the electrochemical reduction of CO2 to CO were evaluated by means of computational hydrogen electrode via calculation of the free energy profile using DFT/B3LYP level of theory in vacuum. The activity of the cluster is ascertained from the fact that the copper atom, present in a two coordinative environment, performs a more selective conversion of CO2 to CO at an applied potential of -0.35 V which is comparatively lower than that of higher coordinative sites. The present study helps to design any sub-nano level metal catalyst for electrochemical reduction of CO2 to various value added chemicals.

Composition Analysis of III-Nitrides at the Nanometer Scale: Comparison of Energy Dispersive X-ray Spectroscopy and Atom Probe Tomography.

PubMed

Bonef, Bastien; Lopez-Haro, Miguel; Amichi, Lynda; Beeler, Mark; Grenier, Adeline; Robin, Eric; Jouneau, Pierre-Henri; Mollard, Nicolas; Mouton, Isabelle; Monroy, Eva; Bougerol, Catherine

2016-12-01

The enhancement of the performance of advanced nitride-based optoelectronic devices requires the fine tuning of their composition, which has to be determined with a high accuracy and at the nanometer scale. For that purpose, we have evaluated and compared energy dispersive X-ray spectroscopy (EDX) in a scanning transmission electron microscope (STEM) and atom probe tomography (APT) in terms of composition analysis of AlGaN/GaN multilayers. Both techniques give comparable results with a composition accuracy better than 0.6 % even for layers as thin as 3 nm. In case of EDX, we show the relevance of correcting the X-ray absorption by simultaneous determination of the mass thickness and chemical composition at each point of the analysis. Limitations of both techniques are discussed when applied to specimens with different geometries or compositions.

Complex biomembrane mimetics on the sub-nanometer scale

DOE PAGES

Heberle, Frederick A.; Pabst, Georg

2017-07-17

Biomimetic lipid vesicles are indispensable tools for gaining insight into the biophysics of cell physiology on the molecular level. The level of complexity of these model systems has steadily increased, and now spans from domain forming lipid mixtures to asymmetric lipid bilayers. We review recent progress in the development and application of elastic neutron and X-ray scattering techniques for studying these systems in situ and under physiologically relevant conditions on the nanometer to sub-nanometer length scales. Particularly we focus on: (i) structural details of coexisting liquid-ordered and liquid-disordered domains, including their thickness and lipid packing mismatch as a function ofmore » a size transition from nanoscopic to macroscopic domains; (ii) membrane-mediated protein partitioning into lipid domains; (iii) the role of the aqueous medium in tuning interactions between membranes and domains; and (iv) leaflet specific structure in asymmetric bilayers and passive lipid flip-flop.« less

Complex biomembrane mimetics on the sub-nanometer scale

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

Heberle, Frederick A.; Pabst, Georg

Biomimetic lipid vesicles are indispensable tools for gaining insight into the biophysics of cell physiology on the molecular level. The level of complexity of these model systems has steadily increased, and now spans from domain forming lipid mixtures to asymmetric lipid bilayers. We review recent progress in the development and application of elastic neutron and X-ray scattering techniques for studying these systems in situ and under physiologically relevant conditions on the nanometer to sub-nanometer length scales. Particularly we focus on: (i) structural details of coexisting liquid-ordered and liquid-disordered domains, including their thickness and lipid packing mismatch as a function ofmore » a size transition from nanoscopic to macroscopic domains; (ii) membrane-mediated protein partitioning into lipid domains; (iii) the role of the aqueous medium in tuning interactions between membranes and domains; and (iv) leaflet specific structure in asymmetric bilayers and passive lipid flip-flop.« less

Substrate comprising a nanometer-scale projection array

DOEpatents

Cui, Yi; Zhu, Jia; Hsu, Ching-Mei; Connor, Stephen T; Yu, Zongfu; Fan, Shanhui; Burkhard, George

2012-11-27

A method for forming a substrate comprising nanometer-scale pillars or cones that project from the surface of the substrate is disclosed. The method enables control over physical characteristics of the projections including diameter, sidewall angle, and tip shape. The method further enables control over the arrangement of the projections including characteristics such as center-to-center spacing and separation distance.

Performance of a Nanometer Resolution BPM System

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

Walston, S.; Chung, C.; Fitsos, P.

2007-04-24

International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. It is important to the ILC design effort to demonstrate that these tolerances can be achieved ideally using beam-based stability measurements. It has been estimated that RF cavity beam position monitors (BPMs) could provide position measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed in the extraction line of the KEK Acceleratormore » Test Facility (ATF) for testing with its ultra-low emittance beam. The three BPMs are rigidly mounted inside an alignment frame on variable-length struts which allow movement in position and angle. We have developed novel methods for extracting the position and tilt information from the BPM signals including a calibration algorithm which is immune to beam jitter. To date, we have been able to demonstrate a resolution of approximately 20 nm over a dynamic range of +/- 20 microns. We report on the progress of these ongoing tests.« less

Boron Nitride-supported Sub-nanometer Pd 6 Clusters for Formic Acid Decomposition: A DFT Study

DOE PAGES

Schimmenti, Roberto; Cortese, Remedios; Duca, Dario; ...

2017-04-25

A periodic, self-consistent planewave DFT study was carried out to explore the potential use of Pd 6 clusters supported on a boron nitride sheet as a catalyst for the selective decomposition of formic acid (HCOOH) to CO 2 and H 2. The competition between formate (HCOO) and carboxyl (COOH) paths on catalytic sites, with different proximities to the support, was studied. Based on energetics alone, the reaction may mainly follow the HCOO route. Slightly lower activation energies were found at the lateral sites of the cluster as compared to top face sites. This is particularly true for the bidentate tomore » monodentate HCOO conversion. Through comparison of results with similar studies on HCOOH decomposition on extended Pd surfaces, it was demonstrated that the existence of undercoordinated sites in the sub-nanometer cluster could play a key role in preferentially stabilizing HCOO over COOH, which is a common CO precursor in this reaction. A hydrogen spillover mechanism was also investigated; migration toward the boron nitride support is not favorable, at least in the early stages of the reaction. However, hydrogen diffusion on the cluster has low barriers compared to those involved in formic acid decomposition.« less

Boron Nitride-supported Sub-nanometer Pd 6 Clusters for Formic Acid Decomposition: A DFT Study

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

Schimmenti, Roberto; Cortese, Remedios; Duca, Dario

A periodic, self-consistent planewave DFT study was carried out to explore the potential use of Pd 6 clusters supported on a boron nitride sheet as a catalyst for the selective decomposition of formic acid (HCOOH) to CO 2 and H 2. The competition between formate (HCOO) and carboxyl (COOH) paths on catalytic sites, with different proximities to the support, was studied. Based on energetics alone, the reaction may mainly follow the HCOO route. Slightly lower activation energies were found at the lateral sites of the cluster as compared to top face sites. This is particularly true for the bidentate tomore » monodentate HCOO conversion. Through comparison of results with similar studies on HCOOH decomposition on extended Pd surfaces, it was demonstrated that the existence of undercoordinated sites in the sub-nanometer cluster could play a key role in preferentially stabilizing HCOO over COOH, which is a common CO precursor in this reaction. A hydrogen spillover mechanism was also investigated; migration toward the boron nitride support is not favorable, at least in the early stages of the reaction. However, hydrogen diffusion on the cluster has low barriers compared to those involved in formic acid decomposition.« less

Photosensitizing effects of nanometer TiO2 on chlorothalonil photodegradation in aqueous solution and on the surface of pepper.

PubMed

Tan, Yong Qiang; Xiong, Hai Xia; Shi, Tao Zhong; Hua, Ri Mao; Wu, Xiang Wei; Cao, Hai Qun; Li, Xue De; Tang, Jun

2013-05-29

The present study examined the effects of anatase nanometer TiO2 on photochemical degradation of chlorothalonil in aqueous solution and on the plant surface. Results showed that nanometer TiO2 exhibited a strong photosensitizing effect on the degradation of chlorothalonil both in aqueous solution and on the surface of green pepper. The photosensitization rate was the highest in the sunlight compared to illumination under high-pressure mercury and UV lamps. Use of distinct hydroxyl radical scavengers indicated that nanometer TiO2 acted by producing hydroxyl radicals with strong oxidizing capacity. Notably, nanometer TiO2 facilitated complete photodegradation of chlorothalonil with no detectable accumulation of the intermediate chlorothalonil-4-hydroxy. Nanometer TiO2 was also active on the surface of green pepper under natural sunlight both inside and outside of plastic greenhouse. These results together suggest that nanometer TiO2 can be used as a photosensitizer to accelerate degradation of the pesticides under greenhouse conditions.

Critical current densities of powder-in-tube MgB2 tapes fabricated with nanometer-size Mg powder

NASA Astrophysics Data System (ADS)

Yamada, H.; Hirakawa, M.; Kumakura, H.; Matsumoto, A.; Kitaguchi, H.

2004-03-01

We fabricated powder-in-tube MgB2/Fe tapes using a powder mixture of nanometer-size Mg and commercial amorphous B and investigated the transport properties. High-purity nanometer-size Mg powder was fabricated by applying the thermal plasma method. 5-10 mol % SiC powder doping was tried to enhance the Jc properties. We found that the use of nanometer-size Mg powder was effective to increase the Jc values. The transport Jc values of the nondoped and 10 mol % SiC-doped tapes prepared with nanometer-size Mg powder reached 90 and 250 A/mm2 at 4.2 K and 10 T, respectively. These values were about five times higher than those of the tapes prepared with commercial Mg powder.

High-density regular arrays of nanometer-scale rods formed on silicon surfaces via femtosecond laser irradiation in water.

PubMed

Shen, Mengyan; Carey, James E; Crouch, Catherine H; Kandyla, Maria; Stone, Howard A; Mazur, Eric

2008-07-01

We report on the formation of high-density regular arrays of nanometer-scale rods using femtosecond laser irradiation of a silicon surface immersed in water. The resulting surface exhibits both micrometer-scale and nanometer-scale structures. The micrometer-scale structure consists of spikes of 5-10 mum width, which are entirely covered by nanometer-scale rods that are roughly 50 nm wide and normal to the surface of the micrometer-scale spikes. The formation of the nanometer-scale rods involves several processes: refraction of laser light in highly excited silicon, interference of scattered and refracted light, rapid cooling in water, roughness-enhanced optical absorptance, and capillary instabilities.

Computational Nanotribology of Nanometer Confined Liquid Films

DTIC Science & Technology

2012-02-29

Nanotribology of Nanometer Confined Liquid Films 5b. GRANT NUMBER FA9550-08-1-0214 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT...NUMBER Yongsheng Leng & Peter T. Cummings 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES...NAME( S ) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM( S ) Joycelyn Harrison AFOSR/RSA 875 North Randolph Street 11. SPONSOR/MONITOR’S REPORT

Synthesis of nanometer-sized fayalite and magnesium-iron(II) mixture olivines

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

Qafoku, Odeta; Ilton, Eugene S.; Bowden, Mark E.

Olivines are divalent orthosilicates with important geologic, biological, and industrial significance and are typically comprised of mixtures of Mg2+ and Fe2+ ranging from forsterite (Mg2SiO4) to fayalite (Fe2SiO4). Investigating the role of Fe(II) in olivine reactivity requires the ability to synthesize olivines that are nanometer-sized, have different percentages of Mg2+ and Fe2+, and have good bulk and surface purity. This article demonstrates a new method for synthesizing nanosized fayalite and Mg-Fe mixture olivines. First, carbonaceous precursors are generated from sucrose, PVA, colloidal silica, Mg2+, and Fe3+. Second, these precursors are calcined in air to burn carbon and create mixtures ofmore » Fe(III)-oxides, forsterite, and SiO2. Finally, calcination in reducing CO-CO2 gas buffer leads to Fe(II)-rich olivines. XRD, Mössbauer, and IR analyses verify good bulk purity and composition. XPS indicates that surface iron is in its reduced Fe(II) form, and surface Si is consistent with olivine. SEM shows particle sizes predominately between 50 and 450 nm, and BET surface areas are 2.8-4.2 m2/g. STEM HAADF analysis demonstrates even distributions of Mg and Fe among the available M1 and M2 sites of the olivine crystals. These nanosized Fe(II)-rich olivines are suitable for laboratory studies with in situ probes that require mineral samples with high reactivity at short timescales.« less

3D nanometer images of biological fibers by directed motion of gold nanoparticles.

PubMed

Estrada, Laura C; Gratton, Enrico

2011-11-09

Using near-infrared femtosecond pulses, we move single gold nanoparticles (AuNPs) along biological fibers, such as collagen and actin filaments. While the AuNP is sliding on the fiber, its trajectory is measured in three dimensions (3D) with nanometer resolution providing a high-resolution image of the fiber. Here, we systematically moved a single AuNP along nanometer-size collagen fibers and actin filament inside chinese hamster ovary K1 living cells, mapping their 3D topography with high fidelity.

Qualitative and quantitative analysis of an additive element in metal oxide nanometer film using laser induced breakdown spectroscopy.

PubMed

Xiu, Junshan; Liu, Shiming; Sun, Meiling; Dong, Lili

2018-01-20

The photoelectric performance of metal ion-doped TiO 2 film will be improved with the changing of the compositions and concentrations of additive elements. In this work, the TiO 2 films doped with different Sn concentrations were obtained with the hydrothermal method. Qualitative and quantitative analysis of the Sn element in TiO 2 film was achieved with laser induced breakdown spectroscopy (LIBS) with the calibration curves plotted accordingly. The photoelectric characteristics of TiO 2 films doped with different Sn content were observed with UV visible absorption spectra and J-V curves. All results showed that Sn doping could improve the optical absorption to be red-shifted and advance the photoelectric properties of the TiO 2 films. We had obtained that when the concentration of Sn doping in TiO 2 films was 11.89  mmol/L, which was calculated by the LIBS calibration curves, the current density of the film was the largest, which indicated the best photoelectric performance. It indicated that LIBS was a potential and feasible measured method, which was applied to qualitative and quantitative analysis of the additive element in metal oxide nanometer film.

Application of maximum-likelihood estimation in optical coherence tomography for nanometer-class thickness estimation

NASA Astrophysics Data System (ADS)

Huang, Jinxin; Yuan, Qun; Tankam, Patrice; Clarkson, Eric; Kupinski, Matthew; Hindman, Holly B.; Aquavella, James V.; Rolland, Jannick P.

2015-03-01

In biophotonics imaging, one important and quantitative task is layer-thickness estimation. In this study, we investigate the approach of combining optical coherence tomography and a maximum-likelihood (ML) estimator for layer thickness estimation in the context of tear film imaging. The motivation of this study is to extend our understanding of tear film dynamics, which is the prerequisite to advance the management of Dry Eye Disease, through the simultaneous estimation of the thickness of the tear film lipid and aqueous layers. The estimator takes into account the different statistical processes associated with the imaging chain. We theoretically investigated the impact of key system parameters, such as the axial point spread functions (PSF) and various sources of noise on measurement uncertainty. Simulations show that an OCT system with a 1 μm axial PSF (FWHM) allows unbiased estimates down to nanometers with nanometer precision. In implementation, we built a customized Fourier domain OCT system that operates in the 600 to 1000 nm spectral window and achieves 0.93 micron axial PSF in corneal epithelium. We then validated the theoretical framework with physical phantoms made of custom optical coatings, with layer thicknesses from tens of nanometers to microns. Results demonstrate unbiased nanometer-class thickness estimates in three different physical phantoms.

Rapid Water Permeation Through Carbon Nanomembranes with Sub-Nanometer Channels.

PubMed

Yang, Yang; Dementyev, Petr; Biere, Niklas; Emmrich, Daniel; Stohmann, Patrick; Korzetz, Riko; Zhang, Xianghui; Beyer, André; Koch, Sascha; Anselmetti, Dario; Gölzhäuser, Armin

2018-05-22

The provision of clean water is a global challenge, and membrane filtration is a key technology to address it. Conventional filtration membranes are constrained by a trade-off between permeance and selectivity. Recently, some nanostructured membranes demonstrated the ability to overcome this limitation by utilizing well-defined carbon nanoconduits that allow a coordinated passage of water molecules. The fabrication of these materials is still very challenging, but their performance inspires research toward nanofabricated membranes. This study reports on molecularly thin membranes with sub-nanometer channels that combine high water selectivity with an exceptionally high permeance. Carbon nanomembranes (CNMs) of ∼1.2 nm thickness are fabricated from terphenylthiol (TPT) monolayers. Scanning probe microscopy and transport measurements reveal that TPT CNMs consist of a dense network of sub-nanometer channels that efficiently block the passage of most gases and liquids. However, water passes through with an extremely high permeance of ∼1.1 × 10 -4 mol·m -2 ·s -1 ·Pa -1 , as does helium, but with a ∼ 2500 times lower flux. Assuming all channels in a TPT CNM are active in mass transport, we find a single-channel permeation of ∼66 water molecules·s -1 ·Pa -1 . This suggests that water molecules translocate fast and cooperatively through the sub-nanometer channels, similar to carbon nanotubes and membrane proteins (aquaporins). CNMs are thus scalable two-dimensional sieves that can be utilized toward energy-efficient water purification.

Observing Optical Plasmons on a Single Nanometer Scale

PubMed Central

Cohen, Moshik; Shavit, Reuven; Zalevsky, Zeev

2014-01-01

The exceptional capability of plasmonic structures to confine light into deep subwavelength volumes has fashioned rapid expansion of interest from both fundamental and applicative perspectives. Surface plasmon nanophotonics enables to investigate light - matter interaction in deep nanoscale and harness electromagnetic and quantum properties of materials, thus opening pathways for tremendous potential applications. However, imaging optical plasmonic waves on a single nanometer scale is yet a substantial challenge mainly due to size and energy considerations. Here, for the first time, we use Kelvin Probe Force Microscopy (KPFM) under optical illumination to image and characterize plasmonic modes. We experimentally demonstrate unprecedented spatial resolution and measurement sensitivity both on the order of a single nanometer. By comparing experimentally obtained images with theoretical calculation results, we show that KPFM maps may provide valuable information on the phase of the optical near field. Additionally, we propose a theoretical model for the relation between surface plasmons and the material workfunction measured by KPFM. Our findings provide the path for using KPFM for high resolution measurements of optical plasmons, prompting the scientific frontier towards quantum plasmonic imaging on submolecular scales. PMID:24556874

Understanding batteries on the micro- and nanometer scale

ScienceCinema

None

2018-01-16

In order to understand performance limitations and failure mechanisms of batteries, one has to investigate processes on the micro- and nanometer scale. A typical failure mechanism in lithium metal batteries is dendritic growth. During discharge, lithium is stripped of the anode surface and migrates to the cathode. During charge, lithium is deposited back on the anode. Repeated cycling can result in stripping and re-deposition that roughens the surface. The roughening of the surface changes the electric field and draws more metal to spikes that are beginning to grow. These can grow with tremendous mechanical force, puncture the separator, and directly connect the anode with the cathode which can create an internal short circuit. This can lead to an uncontrolled discharge reaction, which heats the cell and causes additional exothermic reactions leading to what is called thermal runaway. ORNL has developed a new technology called liquid electron microscopy. In a specially designed sample holder micro-chamber with electron-transparent windows, researchers can hold a liquid and take images of structures and particles at nanometer size. It's the first microscope holder of its kind used to investigate the inside of a battery while cycled.

Nanometals for Solar-to-Chemical Energy Conversion: From Semiconductor-Based Photocatalysis to Plasmon-Mediated Photocatalysis and Photo-Thermocatalysis.

PubMed

Meng, Xianguang; Liu, Lequan; Ouyang, Shuxin; Xu, Hua; Wang, Defa; Zhao, Naiqin; Ye, Jinhua

2016-08-01

Nanometal materials play very important roles in solar-to-chemical energy conversion due to their unique catalytic and optical characteristics. They have found wide applications from semiconductor photocatalysis to rapidly growing surface plasmon-mediated heterogeneous catalysis. The recent research achievements of nanometals are reviewed here, with regard to applications in semiconductor photocatalysis, plasmonic photocatalysis, and plasmonic photo-thermocatalysis. As the first important topic discussed here, the latest progress in the design of nanometal cocatalysts and their applications in semiconductor photocatalysis are introduced. Then, plasmonic photocatalysis and plasmonic photo-thermocatalysis are discussed. A better understanding of electron-driven and temperature-driven catalytic behaviors over plasmonic nanometals is helpful to bridge the present gap between the communities of photocatalysis and conventional catalysis controlled by temperature. The objective here is to provide instructive information on how to take the advantages of the unique functions of nanometals in different types of catalytic processes to improve the efficiency of solar-energy utilization for more practical artificial photosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Performance of a Nanometer Resolution BPM System

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

Vogel, V; Hayano, H; Honda, Y

2005-10-14

International Linear Collider (ILC) interaction region beam sizes and component position stability requirements will be as small as a few nanometers. it is important to the ongoing ILC design effort to demonstrate that these tolerances can be achieved--ideally using beam-based stability measurements. It has been estimated that an RF cavity BPM with modern waveform processing could provide a position measurement resolution of less than one nanometer. Such a system could form the basis of the desired beam-based stability measurement, as well as be used for other specialized purposes. They have developed a high resolution RF cavity BPM and associated electronics.more » A triplet comprised of these BPMs has been installed in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam. The three BPMs are rigidly mounted inside an alignment frame on six variable-length struts which can be used to move the BPMs in position and angle. they have developed novel methods for extracting the position and tilt information from the BPM signals including a robust calibration algorithm which is immune to beam jitter. To date, they have been able to demonstrate a resolution of approximately 20 nm over a dynamic range of {+-} 20 {micro}m. They report on the progress of these ongoing tests.« less

Fractography of glass at the nanometer scale

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

Guilloteau, E.; Arribart, H.; Creuzet, F.

1996-12-01

The authors present a nanometer scale description of the fracture surface of soda-lime glass. This is achieved by the use of Atomic Force Microscopy. The mirror zone is shown to be built with elementary entities, the density of which increases continuously while the mist and hackle zones are approached. Moreover, the overall picture leads to some kind of self-similarity, in the sense that small regions of the hackle zone exhibit the full set of mirror, mist and hackle areas.

Low-Cost Sensors Deliver Nanometer-Accurate Measurements

NASA Technical Reports Server (NTRS)

2015-01-01

As part of a unique partnership program, Kennedy Space Center collaborated with a nearby business school to allow MBA students to examine and analyze the market potential for a selection of NASA-patented technologies. Following the semester, a group of students decided to form Winter Park, Florida-based Juntura Group Inc. to license and sell a technology they had worked with: a sensor capable of detecting position changes as small as 10 nanometers-approximately the thickness of a cell wall.

Highly crystallized nanometer-sized zeolite a with large Cs adsorption capability for the decontamination of water.

PubMed

Torad, Nagy L; Naito, Masanobu; Tatami, Junichi; Endo, Akira; Leo, Sin-Yen; Ishihara, Shinsuke; Wu, Kevin C-W; Wakihara, Toru; Yamauchi, Yusuke

2014-03-01

Nanometer-sized zeolite A with a large cesium (Cs) uptake capability is prepared through a simple post-milling recrystallization method. This method is suitable for producing nanometer-sized zeolite in large scale, as additional organic compounds are not needed to control zeolite nucleation and crystal growth. Herein, we perform a quartz crystal microbalance (QCM) study to evaluate the uptake ability of Cs ions by zeolite, to the best of our knowledge, for the first time. In comparison to micrometer-sized zeolite A, nanometer-sized zeolite A can rapidly accommodate a larger amount of Cs ions into the zeolite crystal structure, owing to its high external surface area. Nanometer-sized zeolite is a promising candidate for the removal of radioactive Cs ions from polluted water. Our QCM study on Cs adsorption uptake behavior provides the information of adsorption kinetics (e.g., adsorption amounts and rates). This technique is applicable to other zeolites, which will be highly valuable for further consideration of radioactive Cs removal in the future. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Imaging Action Potential in Single Mammalian Neurons by Tracking the Accompanying Sub-Nanometer Mechanical Motion.

PubMed

Yang, Yunze; Liu, Xian-Wei; Wang, Hui; Yu, Hui; Guan, Yan; Wang, Shaopeng; Tao, Nongjian

2018-03-28

Action potentials in neurons have been studied traditionally by intracellular electrophysiological recordings and more recently by the fluorescence detection methods. Here we describe a label-free optical imaging method that can measure mechanical motion in single cells with a sub-nanometer detection limit. Using the method, we have observed sub-nanometer mechanical motion accompanying the action potential in single mammalian neurons by averaging the repeated action potential spikes. The shape and width of the transient displacement are similar to those of the electrically recorded action potential, but the amplitude varies from neuron to neuron, and from one region of a neuron to another, ranging from 0.2-0.4 nm. The work indicates that action potentials may be studied noninvasively in single mammalian neurons by label-free imaging of the accompanying sub-nanometer mechanical motion.

Reverse-transformation austenite structure control with micro/nanometer size

NASA Astrophysics Data System (ADS)

Wu, Hui-bin; Niu, Gang; Wu, Feng-juan; Tang, Di

2017-05-01

To control the reverse-transformation austenite structure through manipulation of the micro/nanometer grain structure, the influences of cold deformation and annealing parameters on the microstructure evolution and mechanical properties of 316L austenitic stainless steel were investigated. The samples were first cold-rolled, and then samples deformed to different extents were annealed at different temperatures. The microstructure evolutions were analyzed by optical microscopy, scanning electron microscopy (SEM), magnetic measurements, and X-ray diffraction (XRD); the mechanical properties are also determined by tensile tests. The results showed that the fraction of stain-induced martensite was approximately 72% in the 90% cold-rolled steel. The micro/nanometric microstructure was obtained after reversion annealing at 820-870°C for 60 s. Nearly 100% reversed austenite was obtained in samples annealed at 850°C, where grains with a diameter ≤ 500 nm accounted for 30% and those with a diameter > 0.5 μm accounted for 70%. The micro/nanometer-grain steel exhibited not only a high strength level (approximately 959 MPa) but also a desirable elongation of approximately 45%.

[Clinical observation on nanometer acupoint mounting method for alleviation of myospasm complicated by spinal injury].

PubMed

Zhang, Su-Jie; Si, Tong; Li, Zhi

2008-11-01

To observe clinical effect of nanometer acupoint mounting method for alleviation of myospasm complicated by spinal injury. Sixty cases were randomly divided into an observation group and a control group, 30 cases in each group. The observation group were treated by nanometer mounting at 4 Jiaji (EX-B 2) points each on both sides of the affected spine and Shenshu (BL 23), Shangliao (BL 31), Ciliao (BL 32), Yang-lingquan (GB 34), Xuanzhong (GB 39); and the control group by mounting zinc oxide sticking tablets at the above acupoints. The mounting was replaced once each two days, 7 times constituting one course. One week and one month after the end of 3 courses, their results were recorded, respectively. Before treatment, there was no significant difference between the two groups in grades of the myospasm degree (P > 0.05). One week after the end of treatment, 15 cases were grade I of myospasm, 9 cases were grade II, 5 cases were grade III and 1 case was grade IV in the observation group, and 1 cases grade I, 7 cases grade II, 14 cases grade III, 8 cases grade IV in the control group. Ridit analysis on the data indicated that there were significant differences before and after treatment in the myospasm degree (P < 0.01) and between the two groups after treatment (P < 0.01). One month after the end of treatment, the results were similar to those one week after the end of treatment. Nanometer acupoint mounting method is a new one for alleviation of myospasm complicated by spinal injury, with convenience, safety and no side effect.

High Temperature Mechanical Behavior of Polycrystalline Alumina from Mixed Nanometer and Micrometer Powders

NASA Technical Reports Server (NTRS)

Goldsby, Jon C.

2001-01-01

Sintered aluminum oxide materials were formed using commercial methods from mechanically mixed powders of nano-and micrometer alumina. The powders were consolidated at 1500 and 1600 C with 3.2 and 7.2 ksi applied stress in argon. The conventional micrometer sized powders failed to consolidate. While 100 percent nanometer-sized alumina and its mixture with the micrometer powders achieved less than 99 percent density. Preliminary high temperature creep behavior indicates no super-plastic strains. However high strains (less than 0.65 percent) were generated in the nanometer powder, due to cracks and linked voids initiated by cavitation.

Subnanometer and nanometer catalysts, method for preparing size-selected catalysts

DOEpatents

Vajda, Stefan , Pellin, Michael J.; Elam, Jeffrey W [Elmhurst, IL; Marshall, Christopher L [Naperville, IL; Winans, Randall A [Downers Grove, IL; Meiwes-Broer, Karl-Heinz [Roggentin, GR

2012-04-03

Highly uniform cluster based nanocatalysts supported on technologically relevant supports were synthesized for reactions of top industrial relevance. The Pt-cluster based catalysts outperformed the very best reported ODHP catalyst in both activity (by up to two orders of magnitude higher turn-over frequencies) and in selectivity. The results clearly demonstrate that highly dispersed ultra-small Pt clusters precisely localized on high-surface area supports can lead to affordable new catalysts for highly efficient and economic propene production, including considerably simplified separation of the final product. The combined GISAXS-mass spectrometry provides an excellent tool to monitor the evolution of size and shape of nanocatalyst at action under realistic conditions. Also provided are sub-nanometer gold and sub-nanometer to few nm size-selected silver catalysts which possess size dependent tunable catalytic properties in the epoxidation of alkenes. Invented size-selected cluster deposition provides a unique tool to tune material properties by atom-by-atom fashion, which can be stabilized by protective overcoats.

Subnanometer and nanometer catalysts, method for preparing size-selected catalysts

DOEpatents

Vajda, Stefan [Lisle, IL; Pellin, Michael J [Naperville, IL; Elam, Jeffrey W [Elmhurst, IL; Marshall, Christopher L [Naperville, IL; Winans, Randall A [Downers Grove, IL; Meiwes-Broer, Karl-Heinz [Roggentin, GR

2012-03-27

Highly uniform cluster based nanocatalysts supported on technologically relevant supports were synthesized for reactions of top industrial relevance. The Pt-cluster based catalysts outperformed the very best reported ODHP catalyst in both activity (by up to two orders of magnitude higher turn-over frequencies) and in selectivity. The results clearly demonstrate that highly dispersed ultra-small Pt clusters precisely localized on high-surface area supports can lead to affordable new catalysts for highly efficient and economic propene production, including considerably simplified separation of the final product. The combined GISAXS-mass spectrometry provides an excellent tool to monitor the evolution of size and shape of nanocatalyst at action under realistic conditions. Also provided are sub-nanometer gold and sub-nanometer to few nm size-selected silver catalysts which possess size dependent tunable catalytic properties in the epoxidation of alkenes. Invented size-selected cluster deposition provides a unique tool to tune material properties by atom-by-atom fashion, which can be stabilized by protective overcoats.

Nanometer-Scale Pore Characteristics of Lacustrine Shale, Songliao Basin, NE China

PubMed Central

Wang, Min; Yang, Jinxiu; Wang, Zhiwei; Lu, Shuangfang

2015-01-01

In shale, liquid hydrocarbons are accumulated mainly in nanometer-scale pores or fractures, so the pore types and PSDs (pore size distributions) play a major role in the shale oil occurrence (free or absorbed state), amount of oil, and flow features. The pore types and PSDs of marine shale have been well studied; however, research on lacustrine shale is rare, especially for shale in the oil generation window, although lacustrine shale is deposited widely around the world. To investigate the relationship between nanometer-scale pores and oil occurrence in the lacustrine shale, 10 lacustrine shale core samples from Songliao Basin, NE China were analyzed. Analyses of these samples included geochemical measurements, SEM (scanning electron microscope) observations, low pressure CO2 and N2 adsorption, and high-pressure mercury injection experiments. Analysis results indicate that: (1) Pore types in the lacustrine shale include inter-matrix pores, intergranular pores, organic matter pores, and dissolution pores, and these pores are dominated by mesopores and micropores; (2) There is no apparent correlation between pore volumes and clay content, however, a weak negative correlation is present between total pore volume and carbonate content; (3) Pores in lacustrine shale are well developed when the organic matter maturity (Ro) is >1.0% and the pore volume is positively correlated with the TOC (total organic carbon) content. The statistical results suggest that oil in lacustrine shale mainly occurs in pores with diameters larger than 40 nm. However, more research is needed to determine whether this minimum pore diameter for oil occurrence in lacustrine shale is widely applicable. PMID:26285123

Nanometer-Scale Pore Characteristics of Lacustrine Shale, Songliao Basin, NE China.

PubMed

Wang, Min; Yang, Jinxiu; Wang, Zhiwei; Lu, Shuangfang

2015-01-01

In shale, liquid hydrocarbons are accumulated mainly in nanometer-scale pores or fractures, so the pore types and PSDs (pore size distributions) play a major role in the shale oil occurrence (free or absorbed state), amount of oil, and flow features. The pore types and PSDs of marine shale have been well studied; however, research on lacustrine shale is rare, especially for shale in the oil generation window, although lacustrine shale is deposited widely around the world. To investigate the relationship between nanometer-scale pores and oil occurrence in the lacustrine shale, 10 lacustrine shale core samples from Songliao Basin, NE China were analyzed. Analyses of these samples included geochemical measurements, SEM (scanning electron microscope) observations, low pressure CO2 and N2 adsorption, and high-pressure mercury injection experiments. Analysis results indicate that: (1) Pore types in the lacustrine shale include inter-matrix pores, intergranular pores, organic matter pores, and dissolution pores, and these pores are dominated by mesopores and micropores; (2) There is no apparent correlation between pore volumes and clay content, however, a weak negative correlation is present between total pore volume and carbonate content; (3) Pores in lacustrine shale are well developed when the organic matter maturity (Ro) is >1.0% and the pore volume is positively correlated with the TOC (total organic carbon) content. The statistical results suggest that oil in lacustrine shale mainly occurs in pores with diameters larger than 40 nm. However, more research is needed to determine whether this minimum pore diameter for oil occurrence in lacustrine shale is widely applicable.

Crossed Ga2O3/SnO2 multiwire architecture: a local structure study with nanometer resolution.

PubMed

Martínez-Criado, Gema; Segura-Ruiz, Jaime; Chu, Manh-Hung; Tucoulou, Remi; López, Iñaki; Nogales, Emilio; Mendez, Bianchi; Piqueras, Javier

2014-10-08

Crossed nanowire structures are the basis for high-density integration of a variety of nanodevices. Owing to the critical role of nanowires intersections in creating hybrid architectures, it has become a challenge to investigate the local structure in crossing points in metal oxide nanowires. Thus, if intentionally grown crossed nanowires are well-patterned, an ideal model to study the junction is formed. By combining electron and synchrotron beam nanoprobes, we show here experimental evidence of the role of impurities in the coupling formation, structural modifications, and atomic site configuration based on crossed Ga2O3/SnO2 nanowires. Our experiment opens new avenues for further local structure studies with both nanometer resolution and elemental sensitivity.

Cryogenic colocalization microscopy for nanometer-distance measurements.

PubMed

Weisenburger, Siegfried; Jing, Bo; Hänni, Dominik; Reymond, Luc; Schuler, Benjamin; Renn, Alois; Sandoghdar, Vahid

2014-03-17

The main limiting factor in spatial resolution of localization microscopy is the number of detected photons. Recently we showed that cryogenic measurements improve the photostability of fluorophores, giving access to Angstrom precision in localization of single molecules. Here, we extend this method to colocalize two fluorophores attached to well-defined positions of a double-stranded DNA. By measuring the separations of the fluorophore pairs prepared at different design positions, we verify the feasibility of cryogenic distance measurement with sub-nanometer accuracy. We discuss the important challenges of our method as well as its potential for further improvement and various applications.

Digital image processing of nanometer-size metal particles on amorphous substrates

NASA Technical Reports Server (NTRS)

Soria, F.; Artal, P.; Bescos, J.; Heinemann, K.

1989-01-01

The task of differentiating very small metal aggregates supported on amorphous films from the phase contrast image features inherently stemming from the support is extremely difficult in the nanometer particle size range. Digital image processing was employed to overcome some of the ambiguities in evaluating such micrographs. It was demonstrated that such processing allowed positive particle detection and a limited degree of statistical size analysis even for micrographs where by bare eye examination the distribution between particles and erroneous substrate features would seem highly ambiguous. The smallest size class detected for Pd/C samples peaks at 0.8 nm. This size class was found in various samples prepared under different evaporation conditions and it is concluded that these particles consist of 'a magic number' of 13 atoms and have cubooctahedral or icosahedral crystal structure.

Tracing temperature in a nanometer size region in a picosecond time period.

PubMed

Nakajima, Kaoru; Kitayama, Takumi; Hayashi, Hiroaki; Matsuda, Makoto; Sataka, Masao; Tsujimoto, Masahiko; Toulemonde, Marcel; Bouffard, Serge; Kimura, Kenji

2015-08-21

Irradiation of materials with either swift heavy ions or slow highly charged ions leads to ultrafast heating on a timescale of several picosecond in a region of several nanometer. This ultrafast local heating result in formation of nanostructures, which provide a number of potential applications in nanotechnologies. These nanostructures are believed to be formed when the local temperature rises beyond the melting or boiling point of the material. Conventional techniques, however, are not applicable to measure temperature in such a localized region in a short time period. Here, we propose a novel method for tracing temperature in a nanometer region in a picosecond time period by utilizing desorption of gold nanoparticles around the ion impact position. The feasibility is examined by comparing with the temperature evolution predicted by a theoretical model.

Optically tunable Quincke rotation of a nanometer-thin oblate spheroid

NASA Astrophysics Data System (ADS)

Gu, Yu; Zeng, Haibo

2017-08-01

Ever since the discovery of Quincke rotation (spontaneous rotation of a particle in fluid under a dc electric field) more than 100 years ago [G. Quincke, Ann. Phys. (Leipzig) 295, 417 (1896), 10.1002/andp.18962951102], the strength of the dc field has been the only external parameter to actively tune the rotation speed. In this paper we theoretically propose an optically tunable Quincke rotor exploiting the photoconductivity of a semiconducting nanometer-thin oblate spheroid. A full analysis of the instability of the Quincke rotation reveals that, unlike a prolate spheroid, no bistability is possible in such a dynamical system. In addition, the required material property and the strength of the dc electric field needed to realize the rotation are also elucidated. It is also predicted that light can be used to tune the spinning speed or simply turn on and off the Quincke rotation very effectively.

Preparation of high-strength nanometer scale twinned coating and foil

DOEpatents

Zhang, Xinghang [Los Alamos, NM; Misra, Amit [Los Alamos, NM; Nastasi, Michael A [Santa Fe, NM; Hoagland, Richard G [Santa Fe, NM

2006-07-18

Very high strength single phase stainless steel coating has been prepared by magnetron sputtering onto a substrate. The coating has a unique microstructure of nanometer spaced twins that are parallel to each other and to the substrate surface. For cases where the coating and substrate do not bind strongly, the coating can be peeled off to provide foil.

Porous Architecture of SPS Thick YSZ Coatings Structured at the Nanometer Scale (~50 nm)

NASA Astrophysics Data System (ADS)

Bacciochini, Antoine; Montavon, Ghislain; Ilavsky, Jan; Denoirjean, Alain; Fauchais, Pierre

2010-01-01

Suspension plasma spraying (SPS) is a fairly recent technology that is able to process sub-micrometer-sized or nanometer-sized feedstock particles and permits the deposition of coatings thinner (from 20 to 100 μm) than those resulting from conventional atmospheric plasma spraying (APS). SPS consists of mechanically injecting within the plasma flow a liquid suspension of particles of average diameter varying between 0.02 and 1 μm. Due to the large volume fraction of the internal interfaces and reduced size of stacking defects, thick nanometer- or sub-micrometer-sized coatings exhibit better properties than conventional micrometer-sized ones (e.g., higher coefficients of thermal expansion, lower thermal diffusivity, higher hardness and toughness, better wear resistance, among other coating characteristics and functional properties). They could hence offer pertinent solutions to numerous emerging applications, particularly for energy production, energy saving, etc. Coatings structured at the nanometer scale exhibit nanometer-sized voids. Depending upon the selection of operating parameters, among which plasma power parameters (operating mode, enthalpy, spray distance, etc.), suspension properties (particle size distribution, powder mass percentage, viscosity, etc.), and substrate characteristics (topology, temperature, etc.), different coating architectures can be manufactured, from dense to porous layers, from connected to non-connected network. Nevertheless, the discrimination of porosity in different classes of criteria such as size, shape, orientation, specific surface area, etc., is essential to describe the coating architecture. Moreover, the primary steps of the coating manufacturing process affect significantly the coating porous architecture. These steps need to be further understood. Different types of imaging experiments were performed to understand, describe and quantify the pore level of thick finely structured ceramics coatings.

Progress on glass ceramic ZERODUR enabling nanometer precision

NASA Astrophysics Data System (ADS)

Jedamzik, Ralf; Kunisch, Clemens; Nieder, Johannes; Weber, Peter; Westerhoff, Thomas

2016-03-01

The Semiconductor Industry is making continuous progress in shrinking feature size developing technologies and process to achieve < 10 nm feature size. The required Overlay specification for successful production is in the range one nanometer or even smaller. Consequently, materials designed into metrology systems of exposure or inspection tools need to fulfill ever tighter specification on the coefficient of thermal expansion (CTE). The glass ceramic ZERODUR® is a well-established material in critical components of microlithography wafer stepper and offered with an extremely low coefficient of thermal expansion, the tightest tolerance available on market. SCHOTT is continuously improving manufacturing processes and it's method to measure and characterize the CTE behavior of ZERODUR®. This paper is focusing on the "Advanced Dilatometer" for determination of the CTE developed at SCHOTT in the recent years and introduced into production in Q1 2015. The achievement for improving the absolute CTE measurement accuracy and the reproducibility are described in detail. Those achievements are compared to the CTE measurement accuracy reported by the Physikalische Technische Bundesanstalt (PTB), the National Metrology Institute of Germany. The CTE homogeneity is of highest importance to achieve nanometer precision on larger scales. Additionally, the paper presents data on the short scale CTE homogeneity and its improvement in the last two years. The data presented in this paper will explain the capability of ZERODUR® to enable the extreme precision required for future generation of lithography equipment and processes.

Concept analysis: wrong-site surgery.

PubMed

Watson, Donna S

2015-06-01

A concept analysis was conducted on the concept of wrong-site surgery (WSS) using the principle-based method by Penrod and Hupcey. It included analysis of WSS within the context of epistemological, pragmatic, linguistic, and logical principles. The analysis found that WSS is an important concept that is universally accepted, but the definition could be improved with inclusion of comprehensive labeling for types of WSS that may occur, such as wrong patient, wrong site, wrong level/part, wrong procedure, and wrong side. Wrong-site surgery falls into the domains of both nursing and medicine, and there is limited research on the topic specific to nursing interventions, perceptions, and contributions to prevent WSS. Copyright © 2015 AORN, Inc. Published by Elsevier Inc. All rights reserved.

Grinding model and material removal mechanism of medical nanometer zirconia ceramics.

PubMed

Zhang, Dongkun; Li, Changhe; Jia, Dongzhou; Wang, Sheng; Li, Runze; Qi, Xiaoxiao

2014-01-01

Many patents have been devoted to developing medical nanometer zirconia ceramic grinding techniques that can significantly improve both workpiece surface integrity and grinding quality. Among these patents is a process for preparing ceramic dental implants with a surface for improving osseo-integration by sand abrasive finishing under a jet pressure of 1.5 bar to 8.0 bar and with a grain size of 30 µm to 250 µm. Compared with other materials, nano-zirconia ceramics exhibit unmatched biomedical performance and excellent mechanical properties as medical bone tissue and dentures. The removal mechanism of nano-zirconia materials includes brittle fracture and plastic removal. Brittle fracture involves crack formation, extension, peeling, and chipping to completely remove debris. Plastic removal is similar to chip formation in metal grinding, including rubbing, ploughing, and the formation of grinding debris. The materials are removed in shearing and chipping. During brittle fracture, the grinding-led transverse and radial extension of cracks further generate local peeling of blocks of the material. In material peeling and removal, the mechanical strength and surface quality of the workpiece are also greatly reduced because of crack extension. When grinding occurs in the plastic region, plastic removal is performed, and surface grinding does not generate grinding fissures and surface fracture, producing clinically satisfactory grinding quality. With certain grinding conditions, medical nanometer zirconia ceramics can be removed through plastic flow in ductile regime. In this study, we analyzed the critical conditions for the transfer of brittle and plastic removal in nano-zirconia ceramic grinding as well as the high-quality surface grinding of medical nanometer zirconia ceramics by ELID grinding.

Sensitive SERS detection at the single-particle level based on nanometer-separated mushroom-shaped plasmonic dimers

NASA Astrophysics Data System (ADS)

Xiang, Quan; Li, Zhiqin; Zheng, Mengjie; Liu, Qing; Chen, Yiqin; Yang, Lan; Jiang, Tian; Duan, Huigao

2018-03-01

Elevated metallic nanostructures with nanogaps (<10 nm) possess advantages for surface enhanced Raman scattering (SERS) via the synergic effects of nanogaps and efficient decoupling from the substrate through an elevated three-dimensional (3D) design. In this work, we demonstrate a pattern-transfer-free process to reliably define elevated nanometer-separated mushroom-shaped dimers directly from 3D resist patterns based on the gap-narrowing effect during the metallic film deposition. By controlling the initial size of nanogaps in resist structures and the following deposited film thickness, metallic nanogaps could be tuned at the sub-10 nm scale with single-digit nanometer precision. Both experimental and simulated results revealed that gold dimer on mushroom-shaped pillars have the capability to achieve higher SERS enhancement factor comparing to those plasmonic dimers on cylindrical pillars or on a common SiO2/Si substrate, implying that the nanometer-gapped elevated dimer is an ideal platform to achieve the highest possible field enhancement for various plasmonic applications.

Biophysics: Breaking the Nanometer Barrier

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

Block, Steven

2006-03-20

A new field of scientific exploration – single molecule biophysics – is currently reshaping and redefining our understanding of the mechanochemistry of life. The development of laser-based optical traps, or ‘optical tweezers,’ has allowed for physiological assessments of such precision that bio-molecules can now be measured and studied one at a time. In this colloquium, Professor Block will present findings based on his group’s construction of optical trapping instrumentation that has broken the nanometer barrier, allowing researchers to study single-molecule displacements on the Angstrom level. Focusing on RNA polymerase, the motor enzyme responsible for transcribing the genetic code contained inmore » DNA, Block’s group has been able to measure, in real time, the motion of a single molecule of RNA polymerase as it moves from base to base along the DNA template. A remarkable opportunity to gain insight into one of the most fundamental biological processes of life, this colloquium can not be missed!« less

Size and Shape of Protein Molecules at the Nanometer Level Determined by Sedimentation, Gel Filtration, and Electron Microscopy

PubMed Central

2009-01-01

An important part of characterizing any protein molecule is to determine its size and shape. Sedimentation and gel filtration are hydrodynamic techniques that can be used for this medium resolution structural analysis. This review collects a number of simple calculations that are useful for thinking about protein structure at the nanometer level. Readers are reminded that the Perrin equation is generally not a valid approach to determine the shape of proteins. Instead, a simple guideline is presented, based on the measured sedimentation coefficient and a calculated maximum S, to estimate if a protein is globular or elongated. It is recalled that a gel filtration column fractionates proteins on the basis of their Stokes radius, not molecular weight. The molecular weight can be determined by combining gradient sedimentation and gel filtration, techniques available in most biochemistry laboratories, as originally proposed by Siegel and Monte. Finally, rotary shadowing and negative stain electron microscopy are powerful techniques for resolving the size and shape of single protein molecules and complexes at the nanometer level. A combination of hydrodynamics and electron microscopy is especially powerful. PMID:19495910

Real-Time Imaging of Plant Cell Wall Structure at Nanometer Scale, with Respect to Cellulase Accessibility and Degradation Kinetics (Presentation)

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

Ding, S. Y.

Presentation on real-time imaging of plant cell wall structure at nanometer scale. Objectives are to develop tools to measure biomass at the nanometer scale; elucidate the molecular bases of biomass deconstruction; and identify factors that affect the conversion efficiency of biomass-to-biofuels.

Surface effects on ionic Coulomb blockade in nanometer-size pores

NASA Astrophysics Data System (ADS)

Tanaka, Hiroya; Iizuka, Hideo; Pershin, Yuriy V.; Di Ventra, Massimiliano

2018-01-01

Ionic Coulomb blockade in nanopores is a phenomenon that shares some similarities but also differences with its electronic counterpart. Here, we investigate this phenomenon extensively using all-atom molecular dynamics of ionic transport through nanopores of about one nanometer in diameter and up to several nanometers in length. Our goal is to better understand the role of atomic roughness and structure of the pore walls in the ionic Coulomb blockade. Our numerical results reveal the following general trends. First, the nanopore selectivity changes with its diameter, and the nanopore position in the membrane influences the current strength. Second, the ionic transport through the nanopore takes place in a hopping-like fashion over a set of discretized states caused by local electric fields due to membrane atoms. In some cases, this creates a slow-varying ‘crystal-like’ structure of ions inside the nanopore. Third, while at a given voltage, the resistance of the nanopore depends on its length, the slope of this dependence appears to be independent of the molarity of ions. An effective kinetic model that captures the ionic Coulomb blockade behavior observed in MD simulations is formulated.

Surface effects on ionic Coulomb blockade in nanometer-size pores.

PubMed

Tanaka, Hiroya; Iizuka, Hideo; Pershin, Yuriy V; Ventra, Massimiliano Di

2018-01-12

Ionic Coulomb blockade in nanopores is a phenomenon that shares some similarities but also differences with its electronic counterpart. Here, we investigate this phenomenon extensively using all-atom molecular dynamics of ionic transport through nanopores of about one nanometer in diameter and up to several nanometers in length. Our goal is to better understand the role of atomic roughness and structure of the pore walls in the ionic Coulomb blockade. Our numerical results reveal the following general trends. First, the nanopore selectivity changes with its diameter, and the nanopore position in the membrane influences the current strength. Second, the ionic transport through the nanopore takes place in a hopping-like fashion over a set of discretized states caused by local electric fields due to membrane atoms. In some cases, this creates a slow-varying 'crystal-like' structure of ions inside the nanopore. Third, while at a given voltage, the resistance of the nanopore depends on its length, the slope of this dependence appears to be independent of the molarity of ions. An effective kinetic model that captures the ionic Coulomb blockade behavior observed in MD simulations is formulated.

All-optical lithography process for contacting nanometer precision donor devices

NASA Astrophysics Data System (ADS)

Ward, D. R.; Marshall, M. T.; Campbell, D. M.; Lu, T. M.; Koepke, J. C.; Scrymgeour, D. A.; Bussmann, E.; Misra, S.

2017-11-01

We describe an all-optical lithography process that can make electrical contact to nanometer-precision donor devices fabricated in silicon using scanning tunneling microscopy (STM). This is accomplished by implementing a cleaning procedure in the STM that allows the integration of metal alignment marks and ion-implanted contacts at the wafer level. Low-temperature transport measurements of a patterned device establish the viability of the process.

Nanometer resolution optical coherence tomography using broad bandwidth XUV and soft x-ray radiation

DOE PAGES

Fuchs, Silvio; Rödel, Christian; Blinne, Alexander; ...

2016-02-10

Optical coherence tomography (OCT) is a non-invasive technique for cross-sectional imaging. It is particularly advantageous for applications where conventional microscopy is not able to image deeper layers of samples in a reasonable time, e.g. in fast moving, deeper lying structures. However, at infrared and optical wavelengths, which are commonly used, the axial resolution of OCT is limited to about 1 μm, even if the bandwidth of the light covers a wide spectral range. Here, we present extreme ultraviolet coherence tomography (XCT) and thus introduce a new technique for non-invasive cross-sectional imaging of nanometer structures. XCT exploits the nanometerscale coherence lengthsmore » corresponding to the spectral transmission windows of, e.g., silicon samples. The axial resolution of coherence tomography is thus improved from micrometers to a few nanometers. Tomographic imaging with an axial resolution better than 18 nm is demonstrated for layer-type nanostructures buried in a silicon substrate. Using wavelengths in the water transmission window, nanometer-scale layers of platinum are retrieved with a resolution better than 8 nm. As a result, XCT as a nondestructive method for sub-surface tomographic imaging holds promise for several applications in semiconductor metrology and imaging in the water window.« less

A Micro-Resonant Gas Sensor with Nanometer Clearance between the Pole Plates

PubMed Central

Xu, Lizhong

2018-01-01

In micro-resonant gas sensors, the capacitive detection is widely used because of its simple structure. However, its shortcoming is a weak signal output caused by a small capacitance change. Here, we reduced the initial clearance between the pole plates to the nanometer level, and increased the capacitance between the pole plates and its change during resonator vibration. We propose a fabricating process of the micro-resonant gas sensor by which the initial clearance between the pole plates is reduced to the nanometer level and a micro-resonant gas sensor with 200 nm initial clearance is fabricated. With this sensor, the resonant frequency shifts were measured when they were exposed to several different vapors, and high detection accuracies were obtained. The detection accuracy with respect to ethanol vapor was 0.4 ppm per Hz shift, and the detection accuracy with respect to hydrogen and ammonias vapors was 3 ppm and 0.5 ppm per Hz shift, respectively. PMID:29373546

A Micro-Resonant Gas Sensor with Nanometer Clearance between the Pole Plates.

PubMed

Fu, Xiaorui; Xu, Lizhong

2018-01-26

In micro-resonant gas sensors, the capacitive detection is widely used because of its simple structure. However, its shortcoming is a weak signal output caused by a small capacitance change. Here, we reduced the initial clearance between the pole plates to the nanometer level, and increased the capacitance between the pole plates and its change during resonator vibration. We propose a fabricating process of the micro-resonant gas sensor by which the initial clearance between the pole plates is reduced to the nanometer level and a micro-resonant gas sensor with 200 nm initial clearance is fabricated. With this sensor, the resonant frequency shifts were measured when they were exposed to several different vapors, and high detection accuracies were obtained. The detection accuracy with respect to ethanol vapor was 0.4 ppm per Hz shift, and the detection accuracy with respect to hydrogen and ammonias vapors was 3 ppm and 0.5 ppm per Hz shift, respectively.

All-optical lithography process for contacting nanometer precision donor devices

DOE PAGES

Ward, Daniel Robert; Marshall, Michael Thomas; Campbell, DeAnna Marie; ...

2017-11-06

In this article, we describe an all-optical lithography process that can make electrical contact to nanometer-precision donor devices fabricated in silicon using scanning tunneling microscopy (STM). This is accomplished by implementing a cleaning procedure in the STM that allows the integration of metal alignment marks and ion-implanted contacts at the wafer level. Low-temperature transport measurements of a patterned device establish the viability of the process.

All-optical lithography process for contacting nanometer precision donor devices

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

Ward, Daniel Robert; Marshall, Michael Thomas; Campbell, DeAnna Marie

In this article, we describe an all-optical lithography process that can make electrical contact to nanometer-precision donor devices fabricated in silicon using scanning tunneling microscopy (STM). This is accomplished by implementing a cleaning procedure in the STM that allows the integration of metal alignment marks and ion-implanted contacts at the wafer level. Low-temperature transport measurements of a patterned device establish the viability of the process.

Micrometer- and nanometer-sized platinum group nuggets in micrometeorites from deep-sea sediments of the Indian Ocean

NASA Astrophysics Data System (ADS)

Rudraswami, N. G.; Parashar, K.; Shyam Prasad, M.

2011-03-01

We examined 378 micrometeorites collected from deep-sea sediments of the Indian Ocean of which 175, 180, and 23 are I-type, S-type, and G-type, respectively. Of the 175 I-type spherules, 13 contained platinum group element nuggets (PGNs). The nuggets occur in two distinct sizes and have distinctly different elemental compositions: micrometer (μm)-sized nuggets that are >3 μm contain dominantly Ir, Os, and Ru (iridium-platinum group element or IPGE) and sub-μm (or nanometer)-sized (<1 μm) nuggets, which contain dominantly Pt, Rh, and Pd (palladium—PGE or PPGE). The μm-sized nuggets are found only one per spherule in the cross section observed and are usually found at the edge of the spherule. By contrast, there are hundreds of nanometer-sized nuggets distributed dominantly in the magnetite phases of the spherules, and rarely in the wüstite phases. Both the nugget types are found as separate entities in the same spherule and apparently, nugget formation is a common phenomenon among I-type micrometeorites. However, the μm-sized nuggets are seen in fewer specimens (˜2.5% of the observed I-type spherules). In all, we analyzed four nuggets of μm size and 213 nanometer-sized nuggets from 13 I-type spherules for platinum group elements. Chemically, the μm-sized PGNs contain chondritic ratios of Os/Ir, but are depleted in the more volatile PGE (Pt, Rh, and Pd) relative to chondritic ratios. On the other hand, the nanometer-sized nuggets contain dominantly Pt and Rh. Importantly, the refractory PGEs are conspicuous by their absence in these nanometer nuggets. Palladium, the most volatile PGE is highly depleted (<1.1%) with respect to chondritic ratios in the μm-sized PGNs, and is observed in only 17 of 213 nanometer nuggets with concentrations that are just above the detection limit (≥0.2%). Distinct fractionation of the PGE into IPGE (Ir, Os, Ru) and PPGE seems to take place during the short span of atmospheric entry. These observations suggest several

Accounting for nanometer-thick adventitious carbon contamination in X-ray absorption spectra of carbon-based materials.

PubMed

Mangolini, Filippo; McClimon, J Brandon; Rose, Franck; Carpick, Robert W

2014-12-16

Near-edge X-ray absorption fine structure (NEXAFS) spectroscopy is a powerful technique for characterizing the composition and bonding state of nanoscale materials and the top few nanometers of bulk and thin film specimens. When coupled with imaging methods like photoemission electron microscopy, it enables chemical imaging of materials with nanometer-scale lateral spatial resolution. However, analysis of NEXAFS spectra is often performed under the assumption of structural and compositional homogeneity within the nanometer-scale depth probed by this technique. This assumption can introduce large errors when analyzing the vast majority of solid surfaces due to the presence of complex surface and near-surface structures such as oxides and contamination layers. An analytical methodology is presented for removing the contribution of these nanoscale overlayers from NEXAFS spectra of two-layered systems to provide a corrected photoabsorption spectrum of the substrate. This method relies on the subtraction of the NEXAFS spectrum of the overlayer adsorbed on a reference surface from the spectrum of the two-layer system under investigation, where the thickness of the overlayer is independently determined by X-ray photoelectron spectroscopy (XPS). This approach is applied to NEXAFS data acquired for one of the most challenging cases: air-exposed hard carbon-based materials with adventitious carbon contamination from ambient exposure. The contribution of the adventitious carbon was removed from the as-acquired spectra of ultrananocrystalline diamond (UNCD) and hydrogenated amorphous carbon (a-C:H) to determine the intrinsic photoabsorption NEXAFS spectra of these materials. The method alters the calculated fraction of sp(2)-hybridized carbon from 5 to 20% and reveals that the adventitious contamination can be described as a layer containing carbon and oxygen ([O]/[C] = 0.11 ± 0.02) with a thickness of 0.6 ± 0.2 nm and a fraction of sp(2)-bonded carbon of 0.19 ± 0.03. This

Carbon Nanotubules: Building Blocks for Nanometer-Scale Engineering

NASA Technical Reports Server (NTRS)

Sinnott, Susan B.

1999-01-01

The proposed work consisted of two projects: the investigation of fluid permeation and diffusion through ultrafiltration membranes composed of carbon nanotubules and the design and study of molecular transistors composed of nanotubules. The progress made on each project is summarized and also discussion about additional projects, one of which is a continuation of work supported by another grant, is included. The first project was Liquid Interactions within a Nanotubule Membrane. The second was the design of nanometer-scale hydrocarbon electronic devices. The third was the investigation of Mechanical properties of Nanotubules and Nanotubule bundles. The fourth project was to investigate the growth mechanisms of Carbon Nanotubules.

NANOMETER DIESEL EXHAUST PARTICLES ARE NEUROTOXIC TO DOPAMINERGIC NEURONS THROUGH MICROGLIAL ACTIVATION.

EPA Science Inventory

NANOMETER DIESEL EXHAUST PARTICLES ARE NEUROTOXIC TO DOPAMINERGIC NEURONS THROUGH MICROGLIAL ACTIVATION. M.L. Block1,2, X. Wu1, P. Zhong1, G. Li1, T. Wang1, J.S. Hong1 & B.Veronesi.2
1The Laboratory of Pharmacology and Chemistry, NIEHS, RTP, NC and 2 National Health and Envi...

Nanometer-scale modification and welding of silicon and metallic nanowires with a high-intensity electron beam.

PubMed

Xu, Shengyong; Tian, Mingliang; Wang, Jinguo; Xu, Jian; Redwing, Joan M; Chan, Moses H W

2005-12-01

We demonstrate that a high-intensity electron beam can be applied to create holes, gaps, and other patterns of atomic and nanometer dimensions on a single nanowire, to weld individual nanowires to form metal-metal or metal-semiconductor junctions, and to remove the oxide shell from a crystalline nanowire. In single-crystalline Si nanowires, the beam induces instant local vaporization and local amorphization. In metallic Au, Ag, Cu, and Sn nanowires, the beam induces rapid local surface melting and enhanced surface diffusion, in addition to local vaporization. These studies open up a novel approach for patterning and connecting nanomaterials in devices and circuits at the nanometer scale.

Probing Local Ionic Dynamics in Functional Oxides: From Nanometer to Atomic Scale

NASA Astrophysics Data System (ADS)

Kalinin, Sergei

2014-03-01

Vacancy-mediated electrochemical reactions in oxides underpin multiple applications ranging from electroresistive memories, to chemical sensors to energy conversion systems such as fuel cells. Understanding the functionality in these systems requires probing reversible (oxygen reduction/evolution reaction) and irreversible (cathode degradation and activation, formation of conductive filaments) electrochemical processes. In this talk, I summarize recent advances in probing and controlling these transformations locally on nanometer level using scanning probe microscopy. The localized tip concentrates the electric field in the nanometer scale volume of material, inducing local transition. Measured simultaneously electromechanical response (piezoresponse) or current (conductive AFM) provides the information on the bias-induced changes in material. Here, I illustrate how these methods can be extended to study local electrochemical transformations, including vacancy dynamics in oxides such as titanates, LaxSr1-xCoO3, BiFeO3, and YxZr1-xO2. The formation of electromechanical hysteresis loops and their bias-, temperature- and environment dependences provide insight into local electrochemical mechanisms. In materials such as lanthanum-strontium cobaltite, mapping both reversible vacancy motion and vacancy ordering and static deformation is possible, and can be corroborated by post mortem STEM/EELS studies. In ceria, a broad gamut of electrochemical behaviors is observed as a function of temperature and humidity. The possible strategies for elucidation ionic motion at the electroactive interfaces in oxides using high-resolution electron microscopy and combined ex-situ and in-situ STEM-SPM studies are discussed. In the second part of the talk, probing electrochemical phenomena on in-situ grown surfaces with atomic resolution is illustrated. I present an approach based on the multivariate statistical analysis of the coordination spheres of individual atoms to reveal

Melting behavior of nanometer sized gold isomers

NASA Astrophysics Data System (ADS)

Liu, H. B.; Ascencio, J. A.; Perez-Alvarez, M.; Yacaman, M. J.

2001-09-01

In the present work, the melting behavior of nanometer sized gold isomers was studied using a tight-binding potential with a second momentum approximation. The cases of cuboctahedra, icosahedra, Bagley decahedra, Marks decahedra and star-like decahedra were considered. We calculated the temperature dependence of the total energy and volume during melting and the melting point for different types and sizes of clusters. In addition, the structural evolutions of the nanosized clusters during the melting transition were monitored and revealed. It is found that the melting process has three characteristic time periods for the intermediate nanosized clusters. The whole process includes surface disordering and reordering, followed by surface melting and a final rapid overall melting. This is a new observation, which it is in contrast with previous reports where surface melting is the dominant step.

DSPI technique for nanometer vibration mode measurement

NASA Astrophysics Data System (ADS)

Yue, Kaiduan; Jia, Shuhai; Tan, Yushan

2000-05-01

A time-average DSPI method for nanometer vibration mode measurement is presented in this paper. The phase continuous scan technique is combined with the Bessel fringe-shifting technique to quantitatively analyze the vibration mode by time-average DSPI is used in measurement system. Through the phase continuous scan, the background and speckle items are completely eliminated, which improves the fringe quality and enhances the signal-to-noise ratio of interferogram. There is no need to calibrate the optical phase-shifter exactly in this method. The anti-disturbance capability of this method is higher than that of the phase-stepping technique, so it is robust and easy to be used. In the vibration measurement system, the speckle average technology is used, so the high quality measuring results are obtained.

Nanometer-scale displacement measurement with high resolution using dual cavity Fabry-Pérot interferometer for biomimetic robots.

PubMed

Lee, Jin-Hyuk; Kim, Dae-Hyun

2014-10-01

A sensor of a biomimetic robot has to measure very small environmental changes such as, nanometer scale strains or displacements. Fiber optic sensor can be also one of candidates for the biomimetic sensor because the sensor is like thread and the shape of the sensor is similar to muscle fiber. A fiber optic interferometer, which is an optical-based sensor, can measure displacement precisely, so such device has been widely studied for the measurement of displacement on a nanometer-scale. Especially, a Quadrature Phase-Shifted Fiber Fabry-Pérot interferometer (QPS-FFPI) uses phase-information for this measurement, allowing it to provide a precision result with high resolution. In theory, the QPS-FFPI generates two sinusoidal signals of which the phase difference should be 90 degrees for the exact measurement of the displacement. In order to guarantee the condition of the phase difference, the relative adjustment of the cavities of the optical fibers is required. However, with such precise adjustment it is very hard to fix the proper difference of the two cavities for quadrature-phase-shifting. In this paper, a dual-cavity FFPI is newly proposed to measure the displacement on a nanometer-scale with a specific type of signal processing. In the signal processing, a novel phase-compensation algorithm is applied to force the phase difference to be exactly 90 degrees without any physical adjustment. As a result, the paper shows that the phase-compensated dual-cavity FFPI can effectively measure nanometer-scale displacement with high resolution under dynamic conditions.

Mapping Thermal Expansion Coefficients in Freestanding 2D Materials at the Nanometer Scale

NASA Astrophysics Data System (ADS)

Hu, Xuan; Yasaei, Poya; Jokisaari, Jacob; Öǧüt, Serdar; Salehi-Khojin, Amin; Klie, Robert F.

2018-02-01

Two-dimensional materials, including graphene, transition metal dichalcogenides and their heterostructures, exhibit great potential for a variety of applications, such as transistors, spintronics, and photovoltaics. While the miniaturization offers remarkable improvements in electrical performance, heat dissipation and thermal mismatch can be a problem in designing electronic devices based on two-dimensional materials. Quantifying the thermal expansion coefficient of 2D materials requires temperature measurements at nanometer scale. Here, we introduce a novel nanometer-scale thermometry approach to measure temperature and quantify the thermal expansion coefficients in 2D materials based on scanning transmission electron microscopy combined with electron energy-loss spectroscopy to determine the energy shift of the plasmon resonance peak of 2D materials as a function of sample temperature. By combining these measurements with first-principles modeling, the thermal expansion coefficients (TECs) of single-layer and freestanding graphene and bulk, as well as monolayer MoS2 , MoSe2 , WS2 , or WSe2 , are directly determined and mapped.

Mapping Thermal Expansion Coefficients in Freestanding 2D Materials at the Nanometer Scale.

PubMed

Hu, Xuan; Yasaei, Poya; Jokisaari, Jacob; Öğüt, Serdar; Salehi-Khojin, Amin; Klie, Robert F

2018-02-02

Two-dimensional materials, including graphene, transition metal dichalcogenides and their heterostructures, exhibit great potential for a variety of applications, such as transistors, spintronics, and photovoltaics. While the miniaturization offers remarkable improvements in electrical performance, heat dissipation and thermal mismatch can be a problem in designing electronic devices based on two-dimensional materials. Quantifying the thermal expansion coefficient of 2D materials requires temperature measurements at nanometer scale. Here, we introduce a novel nanometer-scale thermometry approach to measure temperature and quantify the thermal expansion coefficients in 2D materials based on scanning transmission electron microscopy combined with electron energy-loss spectroscopy to determine the energy shift of the plasmon resonance peak of 2D materials as a function of sample temperature. By combining these measurements with first-principles modeling, the thermal expansion coefficients (TECs) of single-layer and freestanding graphene and bulk, as well as monolayer MoS_{2}, MoSe_{2}, WS_{2}, or WSe_{2}, are directly determined and mapped.

Mechanical Properties of Materials with Nanometer Scale Microstructures

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

William D. Nix

2004-10-31

We have been engaged in research on the mechanical properties of materials with nanometer-scale microstructural dimensions. Our attention has been focused on studying the mechanical properties of thin films and interfaces and very small volumes of material. Because the dimensions of thin film samples are small (typically 1 mm in thickness, or less), specialized mechanical testing techniques based on nanoindentation, microbeam bending and dynamic vibration of micromachined structures have been developed and used. Here we report briefly on some of the results we have obtained over the past three years. We also give a summary of all of the dissertations,more » talks and publications completed on this grant during the past 15 years.« less

Techniques for 3D tracking of single molecules with nanometer accuracy in living cells

NASA Astrophysics Data System (ADS)

Gardini, Lucia; Capitanio, Marco; Pavone, Francesco S.

2013-06-01

We describe a microscopy technique that, combining wide-field single molecule microscopy, bifocal imaging and Highly Inclined and Laminated Optical sheet (HILO) microscopy, allows a 3D tracking with nanometer accuracy of single fluorescent molecules in vitro and in living cells.

Rapid Polymer Transport in a Single Nanometer-Scale Pore

NASA Astrophysics Data System (ADS)

Kasianowicz, J. J.

1998-03-01

Protein ion channels are nanometer-scale pores that control the transport of ions and polymers across cell membranes. We compared the ability of charged and nonelectrolyte linear polymers to partition into a single channel reconstituted into a planar lipid bilayer membrane. The entry of each polymer (e.g. monodisperse length single-stranded homopolymeric RNA1 or poly(ethylene glycol)2,3) into the pore caused characteristic transient decreases in the channel's ionic conductance. The ionic current blockades yield detailed information about the physical properties of the polymers and the pore. The biological and technological significance of the results will be discussed.

A scanning tunneling microscope with a scanning range from hundreds of micrometers down to nanometer resolution.

PubMed

Kalkan, Fatih; Zaum, Christopher; Morgenstern, Karina

2012-10-01

A beetle type stage and a flexure scanning stage are combined to form a two stages scanning tunneling microscope (STM). It operates at room temperature in ultrahigh vacuum and is capable of scanning areas up to 300 μm × 450 μm down to resolution on the nanometer scale. This multi-scale STM has been designed and constructed in order to investigate prestructured metallic or semiconducting micro- and nano-structures in real space from atomic-sized structures up to the large-scale environment. The principle of the instrument is demonstrated on two different systems. Gallium nitride based micropillars demonstrate scan areas up to hundreds of micrometers; a Au(111) surface demonstrates nanometer resolution.

Toward in situ x-ray diffraction imaging at the nanometer scale

NASA Astrophysics Data System (ADS)

Zatsepin, Nadia A.; Dilanian, Ruben A.; Nikulin, Andrei Y.; Gable, Brian M.; Muddle, Barry C.; Sakata, Osami

2008-08-01

We present the results of preliminary investigations determining the sensitivity and applicability of a novel x-ray diffraction based nanoscale imaging technique, including simulations and experiments. The ultimate aim of this nascent technique is non-destructive, bulk-material characterization on the nanometer scale, involving three dimensional image reconstructions of embedded nanoparticles and in situ sample characterization. The approach is insensitive to x-ray coherence, making it applicable to synchrotron and laboratory hard x-ray sources, opening the possibility of unprecedented nanometer resolution with the latter. The technique is being developed with a focus on analyzing a technologically important light metal alloy, Al-xCu (where x is 2.0-5.0 %wt). The mono- and polycrystalline samples contain crystallographically oriented, weakly diffracting Al2Cu nanoprecipitates in a sparse, spatially random dispersion within the Al matrix. By employing a triple-axis diffractometer in the non-dispersive setup we collected two-dimensional reciprocal space maps of synchrotron x-rays diffracted from the Al2Cu nanoparticles. The intensity profiles of the diffraction peaks confirmed the sensitivity of the technique to the presence and orientation of the nanoparticles. This is a fundamental step towards in situ observation of such extremely sparse, weakly diffracting nanoprecipitates embedded in light metal alloys at early stages of their growth.

Superhydrophilic TiO2 thin film by nanometer scale surface roughness and dangling bonds

NASA Astrophysics Data System (ADS)

Bharti, Bandna; Kumar, Santosh; Kumar, Rajesh

2016-02-01

A remarkable enhancement in the hydrophilic nature of titanium dioxide (TiO2) films is obtained by surface modification in DC-glow discharge plasma. Thin transparent TiO2 films were coated on glass substrate by sol-gel dip coating method, and exposed in DC-glow discharge plasma. The plasma exposed TiO2 film exhibited a significant change in its wetting property contact angle, which is a representative of wetting property, has reduced to considerable limits 3.02° and 1.85° from its initial value 54.40° and 48.82° for deionized water and ethylene glycol, respectively. It is elucidated that the hydrophilic property of plasma exposed TiO2 films dependent mainly upon nanometer scale surface roughness. Variation, from 4.6 nm to 19.8 nm, in the film surface roughness with exposure time was observed by atomic force microscopy (AFM). Analysis of variation in the values of contact angle and surface roughness with increasing plasma exposure time reveal that the surface roughness is the main factor which makes the modified TiO2 film superhydrophilic. However, a contribution of change in the surface states, to the hydrophilic property, is also observed for small values of the plasma exposure time. Based upon nanometer scale surface roughness and dangling bonds, a variation in the surface energy of TiO2 film from 49.38 to 88.92 mJ/m2 is also observed. X-ray photoelectron spectroscopy (XPS) results show change in the surface states of titanium and oxygen. The observed antifogging properties are the direct results of the development of the superhydrophilic wetting characteristics to TiO2 films.

Fabrications of insulator-protected nanometer-sized electrode gaps

NASA Astrophysics Data System (ADS)

Arima, Akihide; Tsutsui, Makusu; Morikawa, Takanori; Yokota, Kazumichi; Taniguchi, Masateru

2014-03-01

We developed SiO2-coated mechanically controllable break junctions for accurate tunneling current measurements in an ionic solution. By breaking the junction, we created dielectric-protected Au nanoprobes with nanometer separation. We demonstrated that the insulator protection was capable to suppress the ionic contribution to the charge transport through the electrode gap, thereby enabled reliable characterizations of liquid-mediated exponential decay of the tunneling conductance in an electrolyte solution. From this, we found distinct roles of charge points such as molecular dipoles and ion species on the tunneling decay constant, which was attributed to local structures of molecules and ions in the confined space between the sensing electrodes. The device described here would provide improved biomolecular sensing capability of tunneling current sensors.

Electron-Beam Mapping of Vibrational Modes with Nanometer Spatial Resolution.

PubMed

Dwyer, C; Aoki, T; Rez, P; Chang, S L Y; Lovejoy, T C; Krivanek, O L

2016-12-16

We demonstrate that a focused beam of high-energy electrons can be used to map the vibrational modes of a material with a spatial resolution of the order of one nanometer. Our demonstration is performed on boron nitride, a polar dielectric which gives rise to both localized and delocalized electron-vibrational scattering, either of which can be selected in our off-axial experimental geometry. Our experimental results are well supported by our calculations, and should reconcile current controversy regarding the spatial resolution achievable in vibrational mapping with focused electron beams.

TEM Study of Intergranular Fluid Distributions in Rocks at a Nanometer Scale

NASA Astrophysics Data System (ADS)

Hiraga, T.; Anderson, I. M.; Kohlstedt, D. L.

2002-12-01

The distribution of intergranular fluids in rocks plays an essential role in fluid migration and rock rheology. Structural and chemical analyses with sub-nanometer resolution is possible with transmission and scanning-transmission electron microscopy; therefore, it is possible to perform the fine-scale structural analyses required to determine the presence or absence of very thin fluid films along grain boundaries. For aqueous fluids in crustal rocks, Hiraga et al. (2001) observed a fluid morphology controlled by the relative values of the solid-solid and solid-fluid interfacial energies, which resulted in well-defined dihedral angles. Their high-resolution transmission electron microscopy (TEM) observations demonstrate that grain boundaries are tight even at a nanometer scale, consistent with the absence of aqueous fluid films. For partially molten ultra-mafic rocks, two conflicting conclusions have been reached: nanometer-thick melt films wet grain boundaries (Drury and Fitz Gerald 1996; De Kloe et al. 2000) versus essentially all grain boundaries are melt-free (Vaughan et al. 1982; Kohlstedt 1990). To resolve this conflict, Hiraga et al. (2002) examined grain boundaries in quenched partially molten peridotites. Their observations demonstrate the following: (i) Although a small fraction of the grains are separated by relatively thick (~1 μm) layers of melt, lattice fringe images obtained with a high-resolution TEM reveal that most of the remaining boundaries do not contain a thin amorphous phase. (ii) In addition, the composition of olivine-olivine grain boundaries was analyzed with a nano-beam analytical scanning TEM with a probe size of <2 nm. Although the grain boundaries contained no melt film, the concentration of Ca, Al and Ti were enhanced near the boundaries. The segregation of these elements to the grain boundaries formed enriched regions <7 nm wide. A similar pattern of chemical segregation was detected in subsolidus systems. Creep experiments on the

Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

EPA Science Inventory

A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

Enhanced endothelial cell density on NiTi surfaces with sub-micron to nanometer roughness

PubMed Central

Samaroo, Harry D; Lu, Jing; Webster, Thomas J

2008-01-01

The shape memory effect and superelastic properties of NiTi (or Nitinol, a nickel-titanium alloy) have already attracted much attention for various biomedical applications (such as vascular stents, orthodontic wires, orthopedic implants, etc). However, for vascular stents, conventional approaches have required coating NiTi with anti-thrombogenic or anti-inflammatory drug-eluting polymers which as of late have proven problematic for healing atherosclerotic blood vessels. Instead of focusing on the use of drug-eluting anti-thrombogenic or anti-inflammatory proteins, this study focused on promoting the formation of a natural anti-thrombogenic and anti-inflammatory surface on metallic stents: the endothelium. In this study, we synthesized various NiTi substrates with different micron to nanometer surface roughness by using dissimilar dimensions of constituent NiTi powder. Endothelial cell adhesion on these compacts was compared with conventional commercially pure (cp) titanium (Ti) samples. The results after 5 hrs showed that endothelial cells adhered much better on fine grain (<60 μm) compared with coarse grain NiTi compacts (<100 μm). Coarse grain NiTi compacts and conventional Ti promoted similar levels of endothelial cell adhesion. In addition, cells proliferated more after 5 days on NiTi with greater sub-micron and nanoscale surface roughness compared with coarse grain NiTi. In this manner, this study emphasized the positive pole that NiTi with sub-micron to nanometer surface features can play in promoting a natural anti-thrombogenic and anti-inflammatory surface (the endothelium) on a vascular stent and, thus, suggests that more studies should be conducted on NiTi with sub-micron to nanometer surface features. PMID:18488418

Nanometer scale atomic structure of zirconium based bulk metallic glass

NASA Astrophysics Data System (ADS)

Hwang, Jinwoo

We have studied the nanometer scale structure of bulk metallic glass (BMG) using fluctuation electron microscopy (FEM). The nanometer scale medium range order (MRO) in BMG is of significant interest because of its possible relationship to the properties, but the experimental study of the MRO is difficult because conventional diffraction techniques are not sensitive to the MRO scale. FEM is a quantitative transmission electron microscopy technique which measures the nanoscale structural fluctuation associated with MRO in amorphous materials, and provides information about the size, distribution, and internal structure of MRO. In this work, we developed an improved method for FEM using energy-filtered STEM nanodiffraction with highly coherent probes with size up to 11nm in a state-of-the-art Cs- corrected STEM. We also developed an effective way to eliminate the effect of sample thickness variation to the FEM data by using Z-contrast images as references. To study the detailed structure of MRO, we developed a hybrid reverse Monte Carlo (H-RMC) simulation which combines an empirical atomic potential and the FEM data. H-RMC generated model structures that match the experimental data at short and medium range. In addition, the subtle rotational symmetries in the FEM nanodiffraction patterns were analyzed by angular correlation function to reveal more details of the internal structure of MRO. Our experiments and simulations show that Zr-based BMG contains pseudo-planar, crystal-like MRO as well as icosahedral clusters in its nanoscale structure. We found that some icosahedral clusters may be connected, and that structural relaxation by annealing increases the population of icosahedral clusters.

Metal substrates with nanometer scale surface roughness for flexible electronics

NASA Astrophysics Data System (ADS)

Lee, Jong-Lam; Kim, Kisoo

2012-09-01

In this work, we present a novel way in fabricating a metal substrate with nanometer scale in surface roughness (Ra < 1 nm) using a surface roughness transfer method without any polishing or planarization process. Ag film (8 inch, Ra = 0.57 nm) and an INVAR (Invariable alloy) one (20 cm × 20 cm, Ra = 1.40 nm) were demonstrated. The INVAR film was used as a substrate for fabricating organic light emitting diodes (OLED) and organic photovoltaic (OPV). The optical and electrical characteristics of OLEDs and OPVs using the INVAR were comparable to those using a conventional ITO glass substrate.

Nanopore Measurements of Filamentous Viruses Reveal a Sub-nanometer-Scale Stagnant Fluid Layer.

PubMed

McMullen, Angus J; Tang, Jay X; Stein, Derek

2017-11-28

We report measurements and analyses of nanopore translocations by fd and M13, two related strains of filamentous virus that are identical except for their charge densities. The standard continuum theory of electrokinetics greatly overestimates the translocation speed and the conductance associated with counterions for both viruses. Furthermore, fd and M13 behave differently from one another, even translocating in opposite directions under certain conditions. This cannot be explained by Manning-condensed counterions or a number of other proposed models. Instead, we argue that these anomalous findings are consequences of the breakdown of the validity of continuum hydrodynamics at the scale of a few molecular layers. Next to a polyelectrolyte, there exists an extra-viscous, sub-nanometer-thin boundary layer that has a giant influence on the transport characteristics. We show that a stagnant boundary layer captures the essential hydrodynamics and extends the validity of the electrokinetic theory beyond the continuum limit. A stagnant layer with a thickness of about half a nanometer consistently improves predictions of the ionic current change induced by virus translocations and of the translocation velocity for both fd and M13 over a wide range of nanopore dimensions and salt concentrations.

40 CFR 60.2050 - What is a siting analysis?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Analysis § 60.2050 What is a siting analysis? (a) The siting analysis must consider air pollution control... include the consideration of air pollution control alternatives specified in paragraph (a) of this section... Section 60.2050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

RAPID ON-SITE METHODS OF CHEMICAL ANALYSIS

EPA Science Inventory

The analysis of potentially hazardous air, water and soil samples collected and shipped to service laboratories off-site is time consuming and expensive. This Chapter addresses the practical alternative of performing the requisite analytical services on-site. The most significant...

40 CFR 60.1115 - What is a siting analysis?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Waste Combustion Units for Which Construction is Commenced After August 30, 1999 or for Which... § 60.1115 What is a siting analysis? The siting analysis addresses how your municipal waste combustion... environmental and social costs resulting from its location and construction. The analysis must also consider...

Carbon Nanotubules: Building Blocks for Nanometer-Scale Engineering

NASA Technical Reports Server (NTRS)

Sinnott, Susan B.

1997-01-01

Proximal probe technology has provided researchers with new ways to investigate and manipulate matter on the nanometer scale. We have studied, through molecular dynamics simulations, using a many-body empirical potential, the indentation of a hydrogen-terminated, diamond (111 ) surface, with a proximal probe tip that consists of an open, hydrogen-terminated, (10,10) carbon nanotubule. The simulations showed that upon indenting 1.8 A, the tubule deforms but returns to its original shape upon retraction. The Young's modulus of the tubule was determined using the predicted Euler buckling force and was found to be comparable to measured and calculated values. In a second series of simulations, an open (10, 10) nanotubule was heated to 4500 K and allowed to close. We find that at this temperature the resulting cap contains numerous imperfections, including some not mentioned previously in the literature.

Improved measurement performance of the Physikalisch-Technische Bundesanstalt nanometer comparator by integration of a new Zerodur sample carriage

NASA Astrophysics Data System (ADS)

Flügge, Jens; Köning, Rainer; Schötka, Eugen; Weichert, Christoph; Köchert, Paul; Bosse, Harald; Kunzmann, Horst

2014-12-01

The paper describes recent improvements of Physikalisch-Technische Bundesanstalt's (PTB) reference measuring instrument for length graduations, the so-called nanometer comparator, intended to achieve a measurement uncertainty in the domain of 1 nm for a length up to 300 mm. The improvements are based on the design and realization of a new sample carriage, integrated into the existing structure and the optimization of coupling this new device to the vacuum interferometer, by which the length measuring range of approximately 540 mm with sub-nm resolution is given. First, measuring results of the enhanced nanometer comparator are presented and discussed, which show the improvements of the measuring capabilities and verify the step toward the sub-nm accuracy level.

Formation of nanometer-size wires using infiltration into latent nuclear tracks

DOEpatents

Musket, Ronald G.; Felter, Thomas E.

2002-01-01

Nanometer-size wires having a cross-sectional dimension of less than 8 nm with controllable lengths and diameters are produced by infiltrating latent nuclear or ion tracks formed in trackable materials with atomic species. The trackable materials and atomic species are essentially insoluble in each other, thus the wires are formed by thermally driven, self-assembly of the atomic species during annealing, or re-crystallization, of the damage in the latent tracks. Unlike conventional ion track lithography, the inventive method does not require etching of the latent tracks.

Study of nanometer-level precise phase-shift system used in electronic speckle shearography and phase-shift pattern interferometry

NASA Astrophysics Data System (ADS)

Jing, Chao; Liu, Zhongling; Zhou, Ge; Zhang, Yimo

2011-11-01

The nanometer-level precise phase-shift system is designed to realize the phase-shift interferometry in electronic speckle shearography pattern interferometry. The PZT is used as driving component of phase-shift system and translation component of flexure hinge is developed to realize micro displacement of non-friction and non-clearance. Closed-loop control system is designed for high-precision micro displacement, in which embedded digital control system is developed for completing control algorithm and capacitive sensor is used as feedback part for measuring micro displacement in real time. Dynamic model and control model of the nanometer-level precise phase-shift system is analyzed, and high-precision micro displacement is realized with digital PID control algorithm on this basis. It is proved with experiments that the location precision of the precise phase-shift system to step signal of displacement is less than 2nm and the location precision to continuous signal of displacement is less than 5nm, which is satisfied with the request of the electronic speckle shearography and phase-shift pattern interferometry. The stripe images of four-step phase-shift interferometry and the final phase distributed image correlated with distortion of objects are listed in this paper to prove the validity of nanometer-level precise phase-shift system.

Sub-nanometer periodic nonlinearity error in absolute distance interferometers

NASA Astrophysics Data System (ADS)

Yang, Hongxing; Huang, Kaiqi; Hu, Pengcheng; Zhu, Pengfei; Tan, Jiubin; Fan, Zhigang

2015-05-01

Periodic nonlinearity which can result in error in nanometer scale has become a main problem limiting the absolute distance measurement accuracy. In order to eliminate this error, a new integrated interferometer with non-polarizing beam splitter is developed. This leads to disappearing of the frequency and/or polarization mixing. Furthermore, a strict requirement on the laser source polarization is highly reduced. By combining retro-reflector and angel prism, reference and measuring beams can be spatially separated, and therefore, their optical paths are not overlapped. So, the main cause of the periodic nonlinearity error, i.e., the frequency and/or polarization mixing and leakage of beam, is eliminated. Experimental results indicate that the periodic phase error is kept within 0.0018°.

Strengthening of metallic alloys with nanometer-size oxide dispersions

DOEpatents

Flinn, J.E.; Kelly, T.F.

1999-06-01

Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains. 20 figs.

Strengthening of metallic alloys with nanometer-size oxide dispersions

DOEpatents

Flinn, John E.; Kelly, Thomas F.

1999-01-01

Austenitic stainless steels and nickel-base alloys containing, by wt. %, 0.1 to 3.0% V, 0.01 to 0.08% C, 0.01 to 0.5% N, 0.05% max. each of Al and Ti, and 0.005 to 0.10% O, are strengthened and ductility retained by atomization of a metal melt under cover of an inert gas with added oxygen to form approximately 8 nanometer-size hollow oxides within the alloy grains and, when the alloy is aged, strengthened by precipitation of carbides and nitrides nucleated by the hollow oxides. Added strengthening is achieved by nitrogen solid solution strengthening and by the effect of solid oxides precipitated along and pinning grain boundaries to provide temperature-stabilization and refinement of the alloy grains.

Nanometer-Sized Diamond Particle as a Probe for Biolabeling

PubMed Central

Chao, Jui-I.; Perevedentseva, Elena; Chung, Pei-Hua; Liu, Kuang-Kai; Cheng, Chih-Yuan; Chang, Chia-Ching; Cheng, Chia-Liang

2007-01-01

A novel method is proposed using nanometer-sized diamond particles as detection probes for biolabeling. The advantages of nanodiamond's unique properties were demonstrated in its biocompatibility, nontoxicity, easily detected Raman signal, and intrinsic fluorescence from its natural defects without complicated pretreatments. Carboxylated nanodiamond's (cND's) penetration ability, noncytotoxicity, and visualization of cND-cell interactions are demonstrated on A549 human lung epithelial cells. Protein-targeted cell interaction visualization was demonstrated with cND-lysozyme complex interaction with bacteria Escherichia coli. It is shown that the developed biomolecule-cND complex preserves the original functions of the test protein. The easily detected natural fluorescent and Raman intrinsic signals, penetration ability, and low cytotoxicity of cNDs render them promising agents in multiple medical applications. PMID:17513352

Fabrication and characterization of a nanometer-sized optical fiber electrode based on selective chemical etching for scanning electrochemical/optical microscopy.

PubMed

Maruyama, Kenichi; Ohkawa, Hiroyuki; Ogawa, Sho; Ueda, Akio; Niwa, Osamu; Suzuki, Koji

2006-03-15

We have already reported a method for fabricating ultramicroelectrodes (Suzuki, K. JP Patent, 2004-45394, 2004). This method is based on the selective chemical etching of optical fibers. In this work, we undertake a detailed investigation involving a combination of etched optical fibers with various types of tapered tip (protruding-shape, double- (or pencil-) shape and triple-tapered electrode) and insulation with electrophoretic paint. Our goal is to establish a method for fabricating nanometer-sized optical fiber electrodes with high reproducibility. As a result, we realized pencil-shaped and triple-tapered electrodes that had radii in the nanometer range with high reproducibility. These nanometer-sized electrodes showed well-defined sigmoidal curves and stable diffusion-limited responses with cyclic voltammetry. The pencil-shaped optical fiber, which has a conical tip with a cone angle of 20 degrees , was effective for controlling the electrode radius. The pencil-shaped electrodes had higher reproducibility and smaller electrode radii (r(app) < 1.0 nm) than those of other etched optical fiber electrodes. By using a pencil-shaped electrode with a 105-nm radius as a probe, we obtained simultaneous electrochemical and optical images of an implantable interdigitated array electrode. We achieved nanometer-scale resolution with a combination of scanning electrochemical microscopy SECM and optical microscopy. The resolution of the electrochemical and optical images indicated sizes of 300 and 930 nm, respectively. The neurites of living PC12 cells were also successfully imaged on a 1.6-microm scale by using the negative feedback mode of an SECM.

Nanometal Skin of Plasmonic Heterostructures for Highly Efficient Near-Field Scattering Probes

NASA Astrophysics Data System (ADS)

Zito, Gianluigi; Rusciano, Giulia; Vecchione, Antonio; Pesce, Giuseppe; di Girolamo, Rocco; Malafronte, Anna; Sasso, Antonio

2016-08-01

In this work, atomic force microscopy probes are functionalized by virtue of self-assembling monolayers of block copolymer (BCP) micelles loaded either with clusters of silver nanoparticles or bimetallic heterostructures consisting of mixed species of silver and gold nanoparticles. The resulting self-organized patterns allow coating the tips with a sort of nanometal skin made of geometrically confined nanoislands. This approach favors the reproducible engineering and tuning of the plasmonic properties of the resulting structured tip by varying the nanometal loading of the micelles. The newly conceived tips are applied for experiments of tip-enhanced Raman scattering (TERS) spectroscopy and scattering-type scanning near-field optical microscopy (s-SNOM). TERS and s-SNOM probe characterizations on several standard Raman analytes and patterned nanostructures demonstrate excellent enhancement factor with the possibility of fast scanning and spatial resolution <12 nm. In fact, each metal nanoisland consists of a multiscale heterostructure that favors large scattering and near-field amplification. Then, we verify the tips to allow challenging nongap-TER spectroscopy on thick biosamples. Our approach introduces a synergistic chemical functionalization of the tips for versatile inclusion and delivery of plasmonic nanoparticles at the tip apex, which may promote the tuning of the plasmonic properties, a large enhancement, and the possibility of adding new degrees of freedom for tip functionalization.

A general approach to homogeneous sub-nanometer metallic particle/graphene composites by S-coordinator

NASA Astrophysics Data System (ADS)

Wang, Senhao; Wang, Wei; Gu, Shangzhi; Zhang, Guoxin; Song, Ningning

2018-05-01

In this study, sulphur-modified reduced graphene oxide (S-rGO) was employed as substrate to investigate the growth mechanism of metal and metallic nanoparticles (NPs). It is observed that the monodispersed Au, SnO2, FeO(OH) and Co3S4 NPs in sub-nanometer (sub-nm) with narrow size distribution were successfully anchored on S-rGO, respectively. The results indicate that the S contained radicals, viz. the Cdbnd S and Csbnd Ssbnd C functional groups play an important role in determining the homogeneous distribution of NPs on S-rGO by providing active sites for the NPs anchoring and nucleation. In additional, as anode materials for lithium ion batteries (LIBs), the as-synthesized sub-nm sized Co3S4/S-rGO and SnO2/S-rGO composites show excellent Li storage performance. It could be stabilized at ca. 600 mAh/g after formation cycle with the coulombic efficiency of 98%. It is expected that the strategy of growing sub-nm sized metallic component onto graphene by applying sulphur functionalities could be utilized as a general method to prepare monodispersed graphene-based NPs with other metals, especially with transition metals in sub-nm sizes.

Comparison Analysis among Large Amount of SNS Sites

NASA Astrophysics Data System (ADS)

Toriumi, Fujio; Yamamoto, Hitoshi; Suwa, Hirohiko; Okada, Isamu; Izumi, Kiyoshi; Hashimoto, Yasuhiro

In recent years, application of Social Networking Services (SNS) and Blogs are growing as new communication tools on the Internet. Several large-scale SNS sites are prospering; meanwhile, many sites with relatively small scale are offering services. Such small-scale SNSs realize small-group isolated type of communication while neither mixi nor MySpace can do that. However, the studies on SNS are almost about particular large-scale SNSs and cannot analyze whether their results apply for general features or for special characteristics on the SNSs. From the point of view of comparison analysis on SNS, comparison with just several types of those cannot reach a statistically significant level. We analyze many SNS sites with the aim of classifying them by using some approaches. Our paper classifies 50,000 sites for small-scale SNSs and gives their features from the points of network structure, patterns of communication, and growth rate of SNS. The result of analysis for network structure shows that many SNS sites have small-world attribute with short path lengths and high coefficients of their cluster. Distribution of degrees of the SNS sites is close to power law. This result indicates the small-scale SNS sites raise the percentage of users with many friends than mixi. According to the analysis of their coefficients of assortativity, those SNS sites have negative values of assortativity, and that means users with high degree tend to connect users with small degree. Next, we analyze the patterns of user communication. A friend network of SNS is explicit while users' communication behaviors are defined as an implicit network. What kind of relationships do these networks have? To address this question, we obtain some characteristics of users' communication structure and activation patterns of users on the SNS sites. By using new indexes, friend aggregation rate and friend coverage rate, we show that SNS sites with high value of friend coverage rate activate diary postings

Laser interferometer used for nanometer vibration measurements

NASA Astrophysics Data System (ADS)

Sun, Jiaxing; Yang, Jun; Liu, Zhihai; Yuan, Libo

2007-01-01

A novel laser interferometer which adopts alternating modulation phase tracking homodyne technique is proposed. The vibration of nanometer-accuracy is measured with the improved Michelson interferometer by adding cat's eye moving mirror and PZT phase modulation tracking structure. The working principle and the structure of the interferometer are analyzed and the demodulation scheme of alternating phase modulation and tracking is designed. The signal detection is changed from direct current detecting to alternating current detecting. The signal's frequency spectrum transform is achieved, the low-frequency noise jamming is abated, the Signal-to-Noise of the system is improved and the measured resolution is enhanced. Phase tracking technique effectively suppresses the low-frequency noise which is caused by outside environment factors such as temperature and vibration, and the stability of the system is enhanced. The experimental results indicate that for the signal with the frequency of 100Hz and the amplitude of 25nm, the output Signal-to-Noise is 30dB and the measured resolution is 1nm.

40 CFR 60.2895 - What is a siting analysis?

Code of Federal Regulations, 2014 CFR

2014-07-01

... What is a siting analysis? (a) The siting analysis must consider air pollution control alternatives... consideration of air pollution control alternatives specified in paragraph (a) of this section. (c) You must... Section 60.2895 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

40 CFR 60.2895 - What is a siting analysis?

Code of Federal Regulations, 2013 CFR

2013-07-01

... What is a siting analysis? (a) The siting analysis must consider air pollution control alternatives... consideration of air pollution control alternatives specified in paragraph (a) of this section. (c) You must... Section 60.2895 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

40 CFR 60.2895 - What is a siting analysis?

Code of Federal Regulations, 2012 CFR

2012-07-01

... What is a siting analysis? (a) The siting analysis must consider air pollution control alternatives... consideration of air pollution control alternatives specified in paragraph (a) of this section. (c) You must... Section 60.2895 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

A theoretical consideration of ion size effects on the electric double layer and voltammetry of nanometer-sized disk electrodes.

PubMed

Gao, Yu; Liu, Yuwen; Chen, Shengli

2016-12-12

Considering that an electric-double-layer (EDL) structure may significantly impact on the mass transport and charge transfer kinetics at the interfaces of nanometer-sized electrodes, while EDL structures could be altered by the finite sizes of electrolyte and redox ions, the possible effects of ion sizes on EDL structures and voltammetric responses of nanometer-sized disk (nanodisk) electrodes are investigated. Modified Boltzmann and Nernst-Planck (NP) equations, which include the influence of the finite ion volumes, are combined with the Poisson equation and modified Butler-Volmer equation to gain knowledge on how the finite sizes of ions and the nanometer sizes of electrodes may couple with each other to affect the structures and reactivities of a nanoscale electrochemical interface. Two typical ion radii, 0.38 nm and 0.68 nm, which could represent the sizes of the commonly used aqueous electrolyte ions (e.g., the solvated K + ) and the organic electrolyte ions (e.g., the solvated TEA + ) respectively, are considered. The finite size of ions can result in decreased screening of electrode charges, therefore magnifying EDL effects on the ion transport and the electron transfer at electrochemical interfaces. This finite size effect of ions becomes more pronounced for larger ions and at smaller electrodes as the electrode radii is larger than 10 nm. For electrodes with radii smaller than 10 nm, however, the ion size effect may be less pronounced with decreasing the electrode size. This can be explained in terms of the increased edge effect of disk electrodes at nanometer scales, which could relax the ion crowding at/near the outer Helmholtz plane. The conditions and situations under which the ion sizes may have a significant effect on the voltammetry of electrodes are discussed.

Analysis of laparoscopic port site complications: A descriptive study

PubMed Central

Karthik, Somu; Augustine, Alfred Joseph; Shibumon, Mundunadackal Madhavan; Pai, Manohar Varadaraya

2013-01-01

CONTEXT: The rate of port site complications following conventional laparoscopic surgery is about 21 per 100,000 cases. It has shown a proportional rise with increase in the size of the port site incision and trocar. Although rare, complications that occur at the port site include infection, bleeding, and port site hernia. AIMS: To determine the morbidity associated with ports at the site of their insertion in laparoscopic surgery and to identify risk factors for complications. SETTINGS AND DESIGN: Prospective descriptive study. MATERIALS AND METHODS: In the present descriptive study, a total of 570 patients who underwent laparoscopic surgeries for various ailments between August 2009 and July 2011 at our institute were observed for port site complications prospectively and the complications were reviewed. STATISTICAL ANALYSIS USED: Descriptive statistical analysis was carried out in the present study. The statistical software, namely, SPSS 15.0 was used for the analysis of the data. RESULTS: Of the 570 patients undergoing laparoscopic surgery, 17 (3%) had developed complications specifically related to the port site during a minimum follow-up of three months; port site infection (PSI) was the most frequent (n = 10, 1.8%), followed by port site bleeding (n = 4, 0.7%), omentum-related complications (n = 2; 0.35%), and port site metastasis (n = 1, 0.175%). CONCLUSIONS: Laparoscopic surgeries are associated with minimal port site complications. Complications are related to the increased number of ports. Umbilical port involvement is the commonest. Most complications are manageable with minimal morbidity, and can be further minimized with meticulous surgical technique during entry and exit. PMID:23741110

Biosafety of the application of biogenic nanometal powders in husbandry

NASA Astrophysics Data System (ADS)

Anatolievna Nazarova, Anna; Dmitrievna Polischuk, Svetlana; Anatolievna Stepanova, Irina; Ivanovich Churilov, Gennady; Chau Nguyen, Hoai; Buu Ngo, Quoc

2014-03-01

Effects of iron and copper nanopowders (particle size of 20-40 nm) were investigated on rabbits of 1 month age and heifers of 6 months. For introduction of nanometals into the animal's ration, the mixed fodder was treated with the nanometal powder suspension in such a way: 0.08 mg of nanoiron per kg of animal's body weight and 0.04 mg kg-1 for nanocopper. The weight gain of the heifers who received nanoiron and nanocopper after 8 months was 22.4 and 10.7% higher than that of the control, respectively. For the rabbits who received nano Fe and Cu after 3 months, the weight gain was 11.7 and 7.3% compared to the control, respectively. Under the action of metal nanopowders morphological indices of blood were changed in comparison with the control: after 8 months the quantity of erythrocytes increased by 19.6%, hemoglobin by 17.1% and leukocytes by 7.6%. There was a realignment in leukocytic formula: the quantity of lymphocytes increased by 9% compared to the control. Biogenic metals in superdispersive state were able to stimulate immune, enzymatic and humoral systems of the animal's organism, promoting metabolism. Adding Co and Cu metal nanopowders to the bull-calves’ fodder rations increased content of Ca by 31.8 and 0%, Fe by 38.8 and 37.5%, K by 19.2 and 15.3%, Mg by 17.6 and 23.5%, Mn by 9.8 and 45% and Na by 20.5 and 8.8%, respectively, compared to control. Metal nanopowders improved the quality indices and meat productivity of black-white bull-calves, expressed in intensive growth of muscle, tissue and more nutritious meat. The conducted veterinary-sanitary expertise showed that the supplements based on iron, cobalt and copper nanopowders can be used as safe bioactive supplements in animal husbandry.

Single-Enzyme Nanoparticles Armored by a Nanometer-Scale Organic/Inorganic Network

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

Kim, Jungbae; Grate, Jay W.

2003-09-01

We have developed armored single-enzyme nanoparticles (SENs), which dramatically stabilize a protease (a-chymotrypsin, CT) by surrounding each enzyme molecule with a porous composite organic/inorganic shell of less than a few nanometers thick. The armored enzymes show no decrease in CT activity at 30C for four days while free CT activity is rapidly reduced by orders of magnitude. The armored shell around CT is sufficiently thin and porous that it does not place any serious mass-transfer limitation on substrates. This unique approach will have a great impact in using enzymes in various fields.

Site characterization and analysis penetrometer system

NASA Astrophysics Data System (ADS)

Heath, Jeff

1995-04-01

The site characterization and analysis penetrometer system (SCAPS) with laser induced fluorescence (LIF) sensors is being demonstrated as a quick field screening technique to determine the physical and chemical characteristics of subsurface soil and contaminants at hazardous waste sites SCAPS is a collaborative development effort of the Navy, Army, and Air Force under the Tri-Service SCAPS Program. The current SCAPS configuration is designed to quickly and cost-effectively distinguish areas contaminated with petroleum products (hydrocarbons) from unaffected areas.

Direct observation of terahertz surface modes in nanometer-sized liquid water pools.

PubMed

Boyd, J E; Briskman, A; Colvin, V L; Mittleman, D M

2001-10-01

The far-infrared absorption spectrum of nanometer-sized water pools at the core of AOT micelles exhibits a pronounced resonance which is absent in bulk water. The amplitude and spectral position of this resonance are sensitive to the size of the confined water core. This resonance results from size-dependent modifications in the vibrational density of states, and thus has far-reaching implications for chemical processes which involve water sequestered within small cavities. These data represent the first study of the terahertz dielectric properties of confined liquids.

Nanometer-scale imaging and pore-scale fluid flow modeling inchalk

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

Tomutsa, Liviu; Silin, Dmitriy; Radmilovich, Velimir

2005-08-23

For many rocks of high economic interest such as chalk,diatomite, tight gas sands or coal, nanometer scale resolution is neededto resolve the 3D-pore structure, which controls the flow and trapping offluids in the rocks. Such resolutions cannot be achieved with existingtomographic technologies. A new 3D imaging method, based on serialsectioning and using the Focused Ion Beam (FIB) technology has beendeveloped. FIB allows for the milling of layers as thin as 10 nanometersby using accelerated Ga+ ions to sputter atoms from the sample surface.After each milling step, as a new surface is exposed, a 2D image of thissurface is generated. Next,more » the 2D images are stacked to reconstruct the3D pore or grain structure. Resolutions as high as 10 nm are achievableusing this technique. A new image processing method uses directmorphological analysis of the pore space to characterize thepetrophysical properties of diverse formations. In addition to estimationof the petrophysical properties (porosity, permeability, relativepermeability and capillary pressures), the method is used for simulationof fluid displacement processes, such as those encountered in variousimproved oil recovery (IOR) approaches. Computed with the new methodcapillary pressure curves are in good agreement with laboratory data. Themethod has also been applied for visualization of the fluid distributionat various saturations from the new FIB data.« less

A new capacitive long-range displacement nanometer sensor with differential sensing structure based on time-grating

NASA Astrophysics Data System (ADS)

Yu, Zhicheng; Peng, Kai; Liu, Xiaokang; Pu, Hongji; Chen, Ziran

2018-05-01

High-precision displacement sensors, which can measure large displacements with nanometer resolution, are key components in many ultra-precision fabrication machines. In this paper, a new capacitive nanometer displacement sensor with differential sensing structure is proposed for long-range linear displacement measurements based on an approach denoted time grating. Analytical models established using electric field coupling theory and an area integral method indicate that common-mode interference will result in a first-harmonic error in the measurement results. To reduce the common-mode interference, the proposed sensor design employs a differential sensing structure, which adopts a second group of induction electrodes spatially separated from the first group of induction electrodes by a half-pitch length. Experimental results based on a prototype sensor demonstrate that the measurement accuracy and the stability of the sensor are substantially improved after adopting the differential sensing structure. Finally, a prototype sensor achieves a measurement accuracy of  ±200 nm over the full 200 mm measurement range of the sensor.

Data-Driven Surface Traversability Analysis for Mars 2020 Landing Site Selection

NASA Technical Reports Server (NTRS)

Ono, Masahiro; Rothrock, Brandon; Almeida, Eduardo; Ansar, Adnan; Otero, Richard; Huertas, Andres; Heverly, Matthew

2015-01-01

The objective of this paper is three-fold: 1) to describe the engineering challenges in the surface mobility of the Mars 2020 Rover mission that are considered in the landing site selection processs, 2) to introduce new automated traversability analysis capabilities, and 3) to present the preliminary analysis results for top candidate landing sites. The analysis capabilities presented in this paper include automated terrain classification, automated rock detection, digital elevation model (DEM) generation, and multi-ROI (region of interest) route planning. These analysis capabilities enable to fully utilize the vast volume of high-resolution orbiter imagery, quantitatively evaluate surface mobility requirements for each candidate site, and reject subjectivity in the comparison between sites in terms of engineering considerations. The analysis results supported the discussion in the Second Landing Site Workshop held in August 2015, which resulted in selecting eight candidate sites that will be considered in the third workshop.

Putney Basketville Site Biomass CHP Analysis

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

Hunsberger, Randolph; Mosey, Gail

2013-10-01

The U.S. Environmental Protection Agency (EPA) Office of Solid Waste and Emergency Response Center for Program Analysis developed the RE-Powering America's Land initiative to reuse contaminated sites for renewable energy generation when aligned with the community's vision for the site. The Putney, Vermont, Basketville site, formerly the location of a basket-making facility and a paper mill andwoolen mill, was selected for a feasibility study under the program. Biomass was chosen as the renewable energy resource based on abundant woody-biomass resources available in the area. Biomass combined heat and power (CHP) was selected as the technology due to nearby loads, includingmore » Putney Paper and Landmark College.« less

Imaging high-speed friction at the nanometer scale

PubMed Central

Thorén, Per-Anders; de Wijn, Astrid S.; Borgani, Riccardo; Forchheimer, Daniel; Haviland, David B.

2016-01-01

Friction is a complicated phenomenon involving nonlinear dynamics at different length and time scales. Understanding its microscopic origin requires methods for measuring force on nanometer-scale asperities sliding at velocities reaching centimetres per second. Despite enormous advances in experimental technique, this combination of small length scale and high velocity remain elusive. We present a technique for rapidly measuring the frictional forces on a single asperity over a velocity range from zero to several centimetres per second. At each image pixel we obtain the velocity dependence of both conservative and dissipative forces, revealing the transition from stick-slip to smooth sliding friction. We explain measurements on graphite using a modified Prandtl–Tomlinson model, including the damped elastic deformation of the asperity. With its improved force sensitivity and small sliding amplitude, our method enables rapid and detailed surface mapping of the velocity dependence of frictional forces with less than 10 nm spatial resolution. PMID:27958267

Graphene nanoribbon field effect transistor for nanometer-size on-chip temperature sensor

NASA Astrophysics Data System (ADS)

Banadaki, Yaser M.; Srivastava, Ashok; Sharifi, Safura

2016-04-01

Graphene has been extensively investigated as a promising material for various types of high performance sensors due to its large surface-to-volume ratio, remarkably high carrier mobility, high carrier density, high thermal conductivity, extremely high mechanical strength and high signal-to-noise ratio. The power density and the corresponding die temperature can be tremendously high in scaled emerging technology designs, urging the on-chip sensing and controlling of the generated heat in nanometer dimensions. In this paper, we have explored the feasibility of a thin oxide graphene nanoribbon (GNR) as nanometer-size temperature sensor for detecting local on-chip temperature at scaled bias voltages of emerging technology. We have introduced an analytical model for GNR FET for 22nm technology node, which incorporates both thermionic emission of high-energy carriers and band-to-band-tunneling (BTBT) of carriers from drain to channel regions together with different scattering mechanisms due to intrinsic acoustic phonons and optical phonons and line-edge roughness in narrow GNRs. The temperature coefficient of resistivity (TCR) of GNR FET-based temperature sensor shows approximately an order of magnitude higher TCR than large-area graphene FET temperature sensor by accurately choosing of GNR width and bias condition for a temperature set point. At gate bias VGS = 0.55 V, TCR maximizes at room temperature to 2.1×10-2 /K, which is also independent of GNR width, allowing the design of width-free GNR FET for room temperature sensing applications.

Guidance for feasibility analysis of candidate sites : handbook.

DOT National Transportation Integrated Search

2009-09-30

The purpose of this handbook is to provide guidance in determining whether or not speed : harmonization and peak period shoulder is feasible for a given site or set of sites. The content of : this handbook is based on the analysis conducted for this ...

The nature of the Fe–graphene interface at the nanometer level

DOE PAGES

Cattelan, M.; Peng, G. W.; Cavaliere, E.; ...

2014-12-22

The emerging fields of graphene-based magnetic and spintronic devices require a deep understanding of the interface between graphene and ferromagnetic metals. This paper reports a detailed investigation at the nanometer level of the Fe–graphene interface carried out by angle-resolved photoemission, high-resolution photoemission from core levels, near edge X-ray absorption fine structure, scanning tunnelling microscopy and spin polarized density functional theory calculations. Quasi-free-standing graphene was grown on Pt(111), and the iron film was either deposited atop or intercalated beneath graphene. Here, calculations and experimental results show that iron strongly modifies the graphene band structure and lifts its π band spin degeneracy.

Chemical-state-selective mapping at nanometer scale using synchrotron radiation and photoelectron emission microscopy.

PubMed

Hirao, Norie; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Honda, Mitsunori

2010-01-01

For surface analyses of semiconductor devices and various functional materials, it has become indispensable to analyze valence states at nanometer scale due to the rapid developments of nanotechnology. Since a method for microscopic mapping dependent on the chemical bond states has not been established so far, we have developed a photoelectron emission microscopy (PEEM) system combined with synchrotron soft X-ray excitation. The samples investigated were Si/SiO(x) micro-patterns prepared by O(2)(+) ion implantation in Si(001) wafer using a mask. PEEM images excited by various photon energies around the Si K-edge were observed. The lateral spatial resolution of the system was about 41 nm. The brightness of each spot in PEEM images changed depending on the photon energy, due to the X-ray absorption intensity of the respective chemical state. Since the surface of this sample was topographically flat, it has been demonstrated that the present method can be applied to observations of the microscopic pattern, depending not on the morphology, but only on the valence states of silicon. We have also in-situ measured the changes of the PEEM images upon annealing, and elucidated the mechanism of the lateral diffusion of oxygen and valence states of silicon at the nanometer scale.

Urban Rain Gauge Siting Selection Based on Gis-Multicriteria Analysis

NASA Astrophysics Data System (ADS)

Fu, Yanli; Jing, Changfeng; Du, Mingyi

2016-06-01

With the increasingly rapid growth of urbanization and climate change, urban rainfall monitoring as well as urban waterlogging has widely been paid attention. In the light of conventional siting selection methods do not take into consideration of geographic surroundings and spatial-temporal scale for the urban rain gauge site selection, this paper primarily aims at finding the appropriate siting selection rules and methods for rain gauge in urban area. Additionally, for optimization gauge location, a spatial decision support system (DSS) aided by geographical information system (GIS) has been developed. In terms of a series of criteria, the rain gauge optimal site-search problem can be addressed by a multicriteria decision analysis (MCDA). A series of spatial analytical techniques are required for MCDA to identify the prospective sites. With the platform of GIS, using spatial kernel density analysis can reflect the population density; GIS buffer analysis is used to optimize the location with the rain gauge signal transmission character. Experiment results show that the rules and the proposed method are proper for the rain gauge site selection in urban areas, which is significant for the siting selection of urban hydrological facilities and infrastructure, such as water gauge.

On the validity of the Poisson assumption in sampling nanometer-sized aerosols

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

Damit, Brian E; Wu, Dr. Chang-Yu; Cheng, Mengdawn

2014-01-01

A Poisson process is traditionally believed to apply to the sampling of aerosols. For a constant aerosol concentration, it is assumed that a Poisson process describes the fluctuation in the measured concentration because aerosols are stochastically distributed in space. Recent studies, however, have shown that sampling of micrometer-sized aerosols has non-Poissonian behavior with positive correlations. The validity of the Poisson assumption for nanometer-sized aerosols has not been examined and thus was tested in this study. Its validity was tested for four particle sizes - 10 nm, 25 nm, 50 nm and 100 nm - by sampling from indoor air withmore » a DMA- CPC setup to obtain a time series of particle counts. Five metrics were calculated from the data: pair-correlation function (PCF), time-averaged PCF, coefficient of variation, probability of measuring a concentration at least 25% greater than average, and posterior distributions from Bayesian inference. To identify departures from Poissonian behavior, these metrics were also calculated for 1,000 computer-generated Poisson time series with the same mean as the experimental data. For nearly all comparisons, the experimental data fell within the range of 80% of the Poisson-simulation values. Essentially, the metrics for the experimental data were indistinguishable from a simulated Poisson process. The greater influence of Brownian motion for nanometer-sized aerosols may explain the Poissonian behavior observed for smaller aerosols. Although the Poisson assumption was found to be valid in this study, it must be carefully applied as the results here do not definitively prove applicability in all sampling situations.« less

Optical depth localization of nitrogen-vacancy centers in diamond with nanometer accuracy.

PubMed

Häußler, Andreas J; Heller, Pascal; McGuinness, Liam P; Naydenov, Boris; Jelezko, Fedor

2014-12-01

Precise positioning of nitrogen-vacancy (NV) centers is crucial for their application in sensing and quantum information. Here we present a new purely optical technique enabling determination of the NV position with nanometer resolution. We use a confocal microscope to determine the position of individual emitters along the optical axis. Using two separate detection channels, it is possible to simultaneously measure reflected light from the diamond surface and fluorescent light from the NV center and statistically evaluate both signals. An accuracy of 2.6 nm for shallow NV centers was achieved and is consistent with other techniques for depth determination.

Optical field enhancement of nanometer-sized gaps at near-infrared frequencies.

PubMed

Ahn, Jae Sung; Kang, Taehee; Singh, Dilip K; Bahk, Young-Mi; Lee, Hyunhwa; Choi, Soo Bong; Kim, Dai-Sik

2015-02-23

We report near-field and far-field measurements of transmission through nanometer-sized gaps at near-infrared frequencies with varying the gap size from 1 nm to 10 nm. In the far-field measurements, we excluded direct transmission on the metal film surface via interferometric method. Kirchhoff integral formalism was used to relate the far-field intensity to the electric field at the nanogaps. In near-field measurements, field enhancement factors of the nanogaps were quantified by measuring transmission of the nanogaps using near-field scanning optical microscopy. All the measurements produce similar field enhancements of about ten, which we put in the context of comparing with the giant field enhancements in the terahertz regime.

Influence of nanometer scale particulate fillers on some properties of microfilled composite resin.

PubMed

Garoushi, Sufyan; Lassila, Lippo V J; Vallittu, Pekka K

2011-07-01

The aim of this study was to evaluate the effect of different weight fractions of nanometer sized particulate filler on properties of microfilled composite resin. Composite resin was prepared by mixing 33 wt% of resin matrix to the 67 wt% of silane treated microfine silica particulate fillers with various fractions of nanometer sized fillers (0, 10, 15, 20, 30 wt%) using a high speed mixing machine. Test specimens made of the composites were tested with a three-point bending test with a speed of 1.0 mm/min until fracture. Surface microhardess (Vicker's microhardness) was also determined. The volumetric shrinkage in percent was calculated as a buoyancy change in distilled water by means of the Archimedes principle. The degree of monomer conversion (DC%) of the experimental composites containing different nanofiller fractions was measured using FTIR spectroscopy. Surface roughness (Ra) was determined using a surface profilometer. Nanowear measurements were carried out using a nanoindentation device. The water uptake of specimens was also measured. Parameters were statistically analysed by ANOVA (P < 0.05). The group without nanofillers showed the highest flexural strength and modulus, DC% and Ra value. The group with 30% nanofillers had the highest water uptake and volumetric shrinkage. No significant difference was found in Vicker's microhardness and the nanowear of the composites. The plain microfilled composite demonstrated superior properties compared to the composites loaded with nanofillers with the exception of surface roughness.

A Gibbs sampler for Bayesian analysis of site-occupancy data

USGS Publications Warehouse

Dorazio, Robert M.; Rodriguez, Daniel Taylor

2012-01-01

1. A Bayesian analysis of site-occupancy data containing covariates of species occurrence and species detection probabilities is usually completed using Markov chain Monte Carlo methods in conjunction with software programs that can implement those methods for any statistical model, not just site-occupancy models. Although these software programs are quite flexible, considerable experience is often required to specify a model and to initialize the Markov chain so that summaries of the posterior distribution can be estimated efficiently and accurately. 2. As an alternative to these programs, we develop a Gibbs sampler for Bayesian analysis of site-occupancy data that include covariates of species occurrence and species detection probabilities. This Gibbs sampler is based on a class of site-occupancy models in which probabilities of species occurrence and detection are specified as probit-regression functions of site- and survey-specific covariate measurements. 3. To illustrate the Gibbs sampler, we analyse site-occupancy data of the blue hawker, Aeshna cyanea (Odonata, Aeshnidae), a common dragonfly species in Switzerland. Our analysis includes a comparison of results based on Bayesian and classical (non-Bayesian) methods of inference. We also provide code (based on the R software program) for conducting Bayesian and classical analyses of site-occupancy data.

40 CFR 60.1120 - What steps must I complete for my siting analysis?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What steps must I complete for my... Requirements: Siting Analysis § 60.1120 What steps must I complete for my siting analysis? (a) For your siting analysis, you must complete five steps: (1) Prepare an analysis. (2) Make your analysis available to the...

Nanometer Scale Titanium Surface Texturing Are Detected by Signaling Pathways Involving Transient FAK and Src Activations

PubMed Central

Zambuzzi, Willian F.; Bonfante, Estevam A.; Jimbo, Ryo; Hayashi, Mariko; Andersson, Martin; Alves, Gutemberg; Takamori, Esther R.; Beltrão, Paulo J.; Coelho, Paulo G.; Granjeiro, José M.

2014-01-01

Background It is known that physico/chemical alterations on biomaterial surfaces have the capability to modulate cellular behavior, affecting early tissue repair. Such surface modifications are aimed to improve early healing response and, clinically, offer the possibility to shorten the time from implant placement to functional loading. Since FAK and Src are intracellular proteins able to predict the quality of osteoblast adhesion, this study evaluated the osteoblast behavior in response to nanometer scale titanium surface texturing by monitoring FAK and Src phosphorylations. Methodology Four engineered titanium surfaces were used for the study: machined (M), dual acid-etched (DAA), resorbable media microblasted and acid-etched (MBAA), and acid-etch microblasted (AAMB). Surfaces were characterized by scanning electron microscopy, interferometry, atomic force microscopy, x-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. Thereafter, those 4 samples were used to evaluate their cytotoxicity and interference on FAK and Src phosphorylations. Both Src and FAK were investigated by using specific antibody against specific phosphorylation sites. Principal Findings The results showed that both FAK and Src activations were differently modulated as a function of titanium surfaces physico/chemical configuration and protein adsorption. Conclusions It can be suggested that signaling pathways involving both FAK and Src could provide biomarkers to predict osteoblast adhesion onto different surfaces. PMID:24999733

Axial Colocalization of Single Molecules with Nanometer Accuracy Using Metal-Induced Energy Transfer.

PubMed

Isbaner, Sebastian; Karedla, Narain; Kaminska, Izabela; Ruhlandt, Daja; Raab, Mario; Bohlen, Johann; Chizhik, Alexey; Gregor, Ingo; Tinnefeld, Philip; Enderlein, Jörg; Tsukanov, Roman

2018-04-11

Single-molecule localization based super-resolution microscopy has revolutionized optical microscopy and routinely allows for resolving structural details down to a few nanometers. However, there exists a rather large discrepancy between lateral and axial localization accuracy, the latter typically three to five times worse than the former. Here, we use single-molecule metal-induced energy transfer (smMIET) to localize single molecules along the optical axis, and to measure their axial distance with an accuracy of 5 nm. smMIET relies only on fluorescence lifetime measurements and does not require additional complex optical setups.

Cleanability evaluation of ceramic glazes with nanometer far-infrared materials using contact angle measurement.

PubMed

Wang, Lijuan; Liang, Jinsheng; Di, Xingfu; Tang, Qingguo

2014-05-01

The cleanability of easy-to-clean ceramic glazes doped with nanometer far-infrared materials was compared with that of some high-quality household ceramic glazes from the market. The cleanability was evaluated by the contact angle measurement using a sessile drop method with a Dataphysics OCA-30 contact angle analyzer. The results showed that the difference of contact angles of water on the glazes before soiling and after cleaning could be used as a parameter for evaluating the cleanability of the glazes. The relationship between cleanability and surface properties, such as surface free energy and surface topography, was investigated. The surface free energy of the samples and their components were calculated using van Oss acid-base approach. By measuring advancing and receding contact angles, the contact angle hysteresis of the ceramic glazes due to the surface topography was investigated. It was shown that the cleanability of ceramic glazes containing nanometer far-infrared materials (NFIM) is better than that of household ceramic glazes from market, due to a higher ratio of electron-acceptor parameter to electron-donor parameter, which led to the effect of water hydration as well as better hydrophilic property and increased smoothness. The contact angle measurement not only accurately evaluates the cleanability of the ceramic glazes, but also has a contribution to the study of cleanability theory. Moreover, this method is simple, convenient and less sample-consumption.

40 CFR 60.4805 - What is a siting analysis?

Code of Federal Regulations, 2012 CFR

2012-07-01

... siting analysis must consider air pollution control alternatives that minimize, on a site-specific basis, to the maximum extent practicable, potential risks to public health or the environment, including... Section 60.4805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

40 CFR 60.4805 - What is a siting analysis?

Code of Federal Regulations, 2014 CFR

2014-07-01

... siting analysis must consider air pollution control alternatives that minimize, on a site-specific basis, to the maximum extent practicable, potential risks to public health or the environment, including... Section 60.4805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

40 CFR 60.4805 - What is a siting analysis?

Code of Federal Regulations, 2013 CFR

2013-07-01

... siting analysis must consider air pollution control alternatives that minimize, on a site-specific basis, to the maximum extent practicable, potential risks to public health or the environment, including... Section 60.4805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

Understanding the effect of size and shape of gold nanomaterials on nanometal surface energy transfer.

PubMed

Rakshit, Soumyadipta; Moulik, Satya Priya; Bhattacharya, Subhash Chandra

2017-04-01

Gold Nanomaterials (GNMs) interact with fluorophores via electromagnetic coupling under excitation. In this particular work we carried out (to the best of our knowledge for the first time) a comprehensive study of systematic quenching of a blue emitter 2-Anthracene Sulfonate (2-AS) in the presence of gold nanoparticles of different size and shape. We synthesized gold nanomaterials of four different dimensions [nanoparticle (0D), nanorod (1D), nanotriangle (2D) and nanobipyramids (3D)] and realized the underlying effect on the emitting dipole in terms of steady and time resolved fluorescence. Nanometal Surface Energy Transfer (NSET) has already been proved to be the best long range spectroscopic ruler so far. Many attempts have been made to understand the interaction between a fluorescent molecule and gold nanomaterials. But not a single model can interpret alone the interaction phenomena. We have opted three different models to compare the experimental and theoretical data. Due to the presence of size dependent absorptivity and dielectric function, modified CPS-Kuhn model was proved to be the worthiest to comprehend variance of behavior of an emitting dipole in close proximity to nanometal surface by coupling with the image dipole of gold nanomaterials. Copyright © 2016 Elsevier Inc. All rights reserved.

Controlled sub-nanometer tuning of photonic crystal resonator by carbonaceous nano-dots.

PubMed

Seo, Min-Kyo; Park, Hong-Gyu; Yang, Jin-Kyu; Kim, Ju-Young; Kim, Se-Heon; Lee, Yong-Hee

2008-06-23

We propose and demonstrate a scheme that enables spectral tuning of a photonic crystal high-quality resonant mode, in steps finer than 0.2 nm, via electron beam induced deposition of carbonaceous nano-dots. The position and size of a nano-dot with a diameter of <100 nm are controlled to an accuracy on the order of nanometers. The possibility of selective modal tuning is also demonstrated by placing nano-dots at locations pre-determined by theoretical computation. The lasing threshold of a photonic crystal mode tends to increase when a nano-dot is grown at the point of strong electric field, showing the absorptive nature of the nano-dot.

DECISION ANALYSIS OF INCINERATION COSTS IN SUPERFUND SITE REMEDIATION

EPA Science Inventory

This study examines the decision-making process of the remedial design (RD) phase of on-site incineration projects conducted at Superfund sites. Decisions made during RD affect the cost and schedule of remedial action (RA). Decision analysis techniques are used to determine the...

40 CFR 60.2050 - What is a siting analysis?

Code of Federal Regulations, 2014 CFR

2014-07-01

...? (a) The siting analysis must consider air pollution control alternatives that minimize, on a site... air pollution control alternatives specified in paragraph (a) of this section. (c) You must complete... Section 60.2050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

40 CFR 60.2050 - What is a siting analysis?

Code of Federal Regulations, 2013 CFR

2013-07-01

...? (a) The siting analysis must consider air pollution control alternatives that minimize, on a site... air pollution control alternatives specified in paragraph (a) of this section. (c) You must complete... Section 60.2050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

Highly Sensitive, Uniform, and Reproducible Surface-Enhanced Raman Spectroscopy Substrate with Nanometer-Scale Quasi-periodic Nanostructures.

PubMed

Jin, Yuanhao; Wang, Yingcheng; Chen, Mo; Xiao, Xiaoyang; Zhang, Tianfu; Wang, Jiaping; Jiang, Kaili; Fan, Shoushan; Li, Qunqing

2017-09-20

We introduce a simple and cost-effective approach for fabrication of effective surface-enhanced Raman spectroscopy (SERS) substrates. It is shown that the as-fabricated substrates show excellent SERS effects in various probe molecules with high sensitivity, that is, picomolar level detection, and also good reliability. With a SERS enhancement factor beyond 10 8 and excellent reproducibility (deviation less than 5%) of signal intensity, the fabrication of the SERS substrate is realized on a four-inch wafer and proven to be effective in pesticide residue detection. The SERS substrate is realized first through the fabrication of quasi-periodic nanostructured silicon with dimension features in tens of nanometers using superaligned carbon nanotubes networks as an etching mask, after which a large amount of hot spots with nanometer gaps are formed through deposition of a gold film. With rigorous nanostructure design, the enhanced performance of electromagnetic field distribution for nanostructures is optimized. With the advantage of cost-effective large-area preparation, it is believed that the as-fabricated SERS substrate could be used in a wide variety of actual applications where detection of trace amounts is necessary.

Remote optical sensing on the nanometer scale with a bowtie aperture nano-antenna on a fiber tip of scanning near-field optical microscopy

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

Atie, Elie M.; Xie, Zhihua; El Eter, Ali

2015-04-13

Plasmonic nano-antennas have proven the outstanding ability of sensing chemical and physical processes down to the nanometer scale. Sensing is usually achieved within the highly confined optical fields generated resonantly by the nano-antennas, i.e., in contact to the nanostructures. In this paper, we demonstrate the sensing capability of nano-antennas to their larger scale environment, well beyond their plasmonic confinement volume, leading to the concept of “remote” (non contact) sensing on the nanometer scale. On the basis of a bowtie-aperture nano-antenna (BNA) integrated at the apex of a SNOM (Scanning Near-field Optical Microscopy) fiber tip, we introduce an ultra-compact, moveable, andmore » background-free optical nanosensor for the remote sensing of a silicon surface (up to distance of 300 nm). Sensitivity of the BNA to its large scale environment is high enough to expect the monitoring and control of the spacing between the nano-antenna and a silicon surface with sub-nanometer accuracy. This work paves the way towards an alternative class of nanopositioning techniques, based on the monitoring of diffraction-free plasmon resonance, that are alternative to nanomechanical and diffraction-limited optical interference-based devices.« less

Hospital web-site marketing: analysis, issues, and trends.

PubMed

Sanchez, P M; Maier-Donati, P

1999-01-01

As hospitals continue to incorporate web technology into their overall marketing and communications strategies, they face several issues which we explore in this paper. Hospitals' effectiveness in dealing with these issues will affect the benefits received from this technology. We provide an exploratory analysis of current hospital web sites and develop implications for future web site development. Likewise, recommendations based on our research are also provided.

Chirally directed formation of nanometer-scale proline clusters.

PubMed

Myung, Sunnie; Fioroni, Marco; Julian, Ryan R; Koeniger, Stormy L; Baik, Mu-Hyun; Clemmer, David E

2006-08-23

Ion mobility measurements, combined with molecular mechanics simulations, are used to study enantiopure and racemic proline clusters formed by electrospray ionization. Broad distributions of cluster sizes and charge states are observed, ranging from clusters containing only a few proline units to clusters that contain more than 100 proline units (i.e., protonated clusters of the form [xPro + nH](n+) with x = 1 to >100 and n = 1-7). As the sizes of clusters increase, there is direct evidence for nanometer scale, chirally induced organization into specific structures. For n = 4 and 5, enantiopure clusters of approximately 50 to 100 prolines assemble into structures that are more elongated than the most compact structure that is observed from the racemic proline clusters. A molecular analogue, cis-4-hydroxy-proline, displays significantly different behavior, indicating that in addition to the rigidity of the side chain ring, intermolecular interactions are important in the formation of chirally directed clusters. This is the first case in which assemblies of chirally selective elongated structures are observed in this size range of amino acid clusters. Relationships between enantiopurity, cluster shape, and overall energetics are discussed.

Stellar Interferometer Technology Experiment (SITE)

NASA Technical Reports Server (NTRS)

Crawley, Edward F.; Miller, David; Laskin, Robert; Shao, Michael

1995-01-01

The MIT Space Engineering Research Center and the Jet Propulsion Laboratory stand ready to advance science sensor technology for discrete-aperture astronomical instruments such as space-based optical interferometers. The objective of the Stellar Interferometer Technology Experiment (SITE) is to demonstrate system-level functionality of a space-based stellar interferometer through the use of enabling and enhancing Controlled-Structures Technologies (CST). SITE mounts to the Mission Peculiar Experiment Support System inside the Shuttle payload bay. Starlight, entering through two apertures, is steered to a combining plate where it is interferred. Interference requires 27 nanometer pathlength (phasing) and 0.29 archsecond wavefront-tilt (pointing) control. The resulting 15 milli-archsecond angular resolution exceeds that of current earth-orbiting telescopes while maintaining low cost by exploiting active optics and structural control technologies. With these technologies, unforeseen and time-varying disturbances can be rejected while relaxing reliance on ground alignment and calibration. SITE will reduce the risk and cost of advanced optical space systems by validating critical technologies in their operational environment. Moreover, these technologies are directly applicable to commercially driven applications such as precision matching, optical scanning, and vibration and noise control systems for the aerospace, medical, and automotive sectors. The SITE team consists of experienced university, government, and industry researchers, scientists, and engineers with extensive expertise in optical interferometry, nano-precision opto-mechanical control and spaceflight experimentation. The experience exists and the technology is mature. SITE will validate these technologies on a functioning interferometer science sensor in order to confirm definitely their readiness to be baselined for future science missions.

Quantum decrease of capacitance in a nanometer-sized tunnel junction

NASA Astrophysics Data System (ADS)

Untiedt, C.; Saenz, G.; Olivera, B.; Corso, M.; Sabater, C.; Pascual, J. I.

2013-03-01

We have studied the capacitance of the tunnel junction defined by the tip and sample of a Scanning Tunnelling Microscope through the measurement of the electrostatic forces and impedance of the junction. A decrease of the capacitance when a tunnel current is present has shown to be a more general phenomenon as previously reported in other systems. On another hand, an unexpected reduction of the capacitance is also observed when increasing the applied voltage above the work function energy of the electrodes to the Field Emission (FE) regime, and the decrease of capacitance due to a single FE-Resonance has been characterized. All these effects should be considered when doing measurements of the electronic characteristics of nanometer-sized electronic devices and have been neglected up to date. Spanish government (FIS2010-21883-C02-01, CONSOLIDER CSD2007-0010), Comunidad Valenciana (ACOMP/2012/127 and PROMETEO/2012/011)

Mapping and analysis of phosphorylation sites: a quick guide for cell biologists

PubMed Central

Dephoure, Noah; Gould, Kathleen L.; Gygi, Steven P.; Kellogg, Douglas R.

2013-01-01

A mechanistic understanding of signaling networks requires identification and analysis of phosphorylation sites. Mass spectrometry offers a rapid and highly sensitive approach to mapping phosphorylation sites. However, mass spectrometry has significant limitations that must be considered when planning to carry out phosphorylation-site mapping. Here we provide an overview of key information that should be taken into consideration before beginning phosphorylation-site analysis, as well as a step-by-step guide for carrying out successful experiments. PMID:23447708

Development of a site analysis tool for distributed wind projects

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

Shaw, Shawn

The Cadmus Group, Inc., in collaboration with the National Renewable Energy Laboratory (NREL) and Encraft, was awarded a grant from the Department of Energy (DOE) to develop a site analysis tool for distributed wind technologies. As the principal investigator for this project, Mr. Shawn Shaw was responsible for overall project management, direction, and technical approach. The product resulting from this project is the Distributed Wind Site Analysis Tool (DSAT), a software tool for analyzing proposed sites for distributed wind technology (DWT) systems. This user-friendly tool supports the long-term growth and stability of the DWT market by providing reliable, realistic estimatesmore » of site and system energy output and feasibility. DSAT-which is accessible online and requires no purchase or download of software-is available in two account types; Standard: This free account allows the user to analyze a limited number of sites and to produce a system performance report for each; and Professional: For a small annual fee users can analyze an unlimited number of sites, produce system performance reports, and generate other customizable reports containing key information such as visual influence and wind resources. The tool’s interactive maps allow users to create site models that incorporate the obstructions and terrain types present. Users can generate site reports immediately after entering the requisite site information. Ideally, this tool also educates users regarding good site selection and effective evaluation practices.« less

Detecting Intramolecular Conformational Dynamics of Single Molecules in Short Distance Range with Sub-Nanometer Sensitivity

PubMed Central

Zhou, Ruobo; Kunzelmann, Simone; Webb, Martin R.; Ha, Taekjip

2011-01-01

Single molecule detection is useful for characterizing nanoscale objects such as biological macromolecules, nano-particles and nano-devices with nano-meter spatial resolution. Fluorescence resonance energy transfer (FRET) is widely used as a single-molecule assay to monitor intramolecular dynamics in the distance range of 3–8 nm. Here we demonstrate that self-quenching of two rhodamine derivatives can be used to detect small conformational dynamics corresponding to sub-nanometer distance changes in a FRET-insensitive short range at the single molecule level. A ParM protein mutant labeled with two rhodamines works as a single molecule ADP sensor which has 20 times brighter fluorescence signal in the ADP bound state than the unbound state. Single molecule time trajectories show discrete transitions between fluorescence on and off states that can be directly ascribed to ADP binding and dissociation events. The conformational changes observed with 20:1 contrast are only 0.5 nm in magnitude and are between crystallographic distances of 1.6 nm and 2.1 nm, demonstrating exquisite sensitivity to short distance scale changes. The systems also allowed us to gain information on the photophysics of self-quenching induced by rhodamine stacking: (1) photobleaching of either of the two rhodamines eliminates quenching of the other rhodamine fluorophore and (2) photobleaching from the highly quenched, stacked state is only two-fold slower than from the unstacked state. PMID:22023515

Nanometer polymer surface features: the influence on surface energy, protein adsorption and endothelial cell adhesion

NASA Astrophysics Data System (ADS)

Carpenter, Joseph; Khang, Dongwoo; Webster, Thomas J.

2008-12-01

Current small diameter (<5 mm) synthetic vascular graft materials exhibit poor long-term patency due to thrombosis and intimal hyperplasia. Tissue engineered solutions have yielded functional vascular tissue, but some require an eight-week in vitro culture period prior to implantation—too long for immediate clinical bedside applications. Previous in vitro studies have shown that nanostructured poly(lactic-co-glycolic acid) (PLGA) surfaces elevated endothelial cell adhesion, proliferation, and extracellular matrix synthesis when compared to nanosmooth surfaces. Nonetheless, these studies failed to address the importance of lateral and vertical surface feature dimensionality coupled with surface free energy; nor did such studies elicit an optimum specific surface feature size for promoting endothelial cell adhesion. In this study, a series of highly ordered nanometer to submicron structured PLGA surfaces of identical chemistry were created using a technique employing polystyrene nanobeads and poly(dimethylsiloxane) (PDMS) molds. Results demonstrated increased endothelial cell adhesion on PLGA surfaces with vertical surface features of size less than 18.87 nm but greater than 0 nm due to increased surface energy and subsequently protein (fibronectin and collagen type IV) adsorption. Furthermore, this study provided evidence that the vertical dimension of nanometer surface features, rather than the lateral dimension, is largely responsible for these increases. In this manner, this study provides key design parameters that may promote vascular graft efficacy.

Mesoscale carbon sequestration site screening and CCS infrastructure analysis.

PubMed

Keating, Gordon N; Middleton, Richard S; Stauffer, Philip H; Viswanathan, Hari S; Letellier, Bruce C; Pasqualini, Donatella; Pawar, Rajesh J; Wolfsberg, Andrew V

2011-01-01

We explore carbon capture and sequestration (CCS) at the meso-scale, a level of study between regional carbon accounting and highly detailed reservoir models for individual sites. We develop an approach to CO(2) sequestration site screening for industries or energy development policies that involves identification of appropriate sequestration basin, analysis of geologic formations, definition of surface sites, design of infrastructure, and analysis of CO(2) transport and storage costs. Our case study involves carbon management for potential oil shale development in the Piceance-Uinta Basin, CO and UT. This study uses new capabilities of the CO(2)-PENS model for site screening, including reservoir capacity, injectivity, and cost calculations for simple reservoirs at multiple sites. We couple this with a model of optimized source-sink-network infrastructure (SimCCS) to design pipeline networks and minimize CCS cost for a given industry or region. The CLEAR(uff) dynamical assessment model calculates the CO(2) source term for various oil production levels. Nine sites in a 13,300 km(2) area have the capacity to store 6.5 GtCO(2), corresponding to shale-oil production of 1.3 Mbbl/day for 50 years (about 1/4 of U.S. crude oil production). Our results highlight the complex, nonlinear relationship between the spatial deployment of CCS infrastructure and the oil-shale production rate.

Traffic operational evaluation of traffic impact analysis (TIA) case sites.

DOT National Transportation Integrated Search

2010-09-22

This report summarizes traffic operational evaluation of six select traffic impact analysis (TIA) case sites and the effectiveness of forecasting methods used in TIA studies. Six TIA case sites comprising 15 signalized intersections and 2 unsignalize...

Carbon nanotube transistors scaled to a 40-nanometer footprint.

PubMed

Cao, Qing; Tersoff, Jerry; Farmer, Damon B; Zhu, Yu; Han, Shu-Jen

2017-06-30

The International Technology Roadmap for Semiconductors challenges the device research community to reduce the transistor footprint containing all components to 40 nanometers within the next decade. We report on a p-channel transistor scaled to such an extremely small dimension. Built on one semiconducting carbon nanotube, it occupies less than half the space of leading silicon technologies, while delivering a significantly higher pitch-normalized current density-above 0.9 milliampere per micrometer at a low supply voltage of 0.5 volts with a subthreshold swing of 85 millivolts per decade. Furthermore, we show transistors with the same small footprint built on actual high-density arrays of such nanotubes that deliver higher current than that of the best-competing silicon devices under the same overdrive, without any normalization. We achieve this using low-resistance end-bonded contacts, a high-purity semiconducting carbon nanotube source, and self-assembly to pack nanotubes into full surface-coverage aligned arrays. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Depositing nanometer-sized particles of metals onto carbon allotropes

NASA Technical Reports Server (NTRS)

Delozier, Donavon M. (Inventor); Fallbach, Michael J. (Inventor); Smith, Joseph G. (Inventor); Watson, Kent A. (Inventor); Ghose, Sayata (Inventor); Connell, John W. (Inventor)

2010-01-01

A process for depositing nanometer-sized metal particles onto a substrate in the absence of aqueous solvents, organic solvents, and reducing agents, and without any required pre-treatment of the substrate, includes preparing an admixture of a metal compound and a substrate by dry mixing a chosen amount of the metal compound with a chosen amount of the substrate; and supplying energy to the admixture in an amount sufficient to deposit zero valance metal particles onto the substrate. This process gives rise to a number of deposited metallic particle sizes which may be controlled. The compositions prepared by this process are used to produce polymer composites by combining them with readily available commodity and engineering plastics. The polymer composites are used as coatings, or they are used to fabricate articles, such as free-standing films, fibers, fabrics, foams, molded and laminated articles, tubes, adhesives, and fiber reinforced articles. These articles are well-suited for many applications requiring thermal conductivity, electrical conductivity, antibacterial activity, catalytic activity, and combinations thereof.

Analysis of Discussion Board Interaction in an Online Peer Mentoring Site

ERIC Educational Resources Information Center

Ruane, Regina; Lee, Vera J.

2016-01-01

This study uses Critical Discourse Analysis and Social Network Analysis to examine an online peer mentoring site created to unite first-year and third-year preservice teachers enrolled in an undergraduate teacher education program. The peer mentoring site was developed to provide both first-year preservice teachers and more experienced peers the…

Resistive switching in a few nanometers thick tantalum oxide film formed by a metal oxidation

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

Ohno, Takeo, E-mail: t-ohno@wpi-aimr.tohoku.ac.jp; Japan Science and Technology Agency; Samukawa, Seiji, E-mail: samukawa@ifs.tohoku.ac.jp

2015-04-27

Resistive switching in a Cu/Ta{sub 2}O{sub 5}/Pt structure that consisted of a few nanometer-thick Ta{sub 2}O{sub 5} film was demonstrated. The Ta{sub 2}O{sub 5} film with thicknesses of 2–5 nm was formed with a combination of Ta metal film deposition and neutral oxygen particle irradiation at room temperature. The device exhibited a bipolar resistive switching with a threshold voltage of 0.2 V and multilevel switching operation.

Helium Ion Microscope: A New Tool for Sub-nanometer Imaging of Soft Materials

NASA Astrophysics Data System (ADS)

Shutthanandan, V.; Arey, B.; Smallwood, C. R.; Evans, J. E.

2017-12-01

High-resolution inspection of surface details is needed in many biological and environmental researches to understand the Soil organic material (SOM)-mineral interactions along with identifying microbial communities and their interactions. SOM shares many imaging characteristics with biological samples and getting true surface details from these materials are challenging since they consist of low atomic number materials. FE-SEM imaging is the main imagining technique used to image these materials in the past. These SEM images often show loss of resolution and increase noise due to beam damage and charging issues. Newly developed Helium Ion Microscope (HIM), on the other hand can overcome these difficulties and give very fine details. HIM is very similar to scanning electron microscopy (SEM) but instead of using electrons as a probe beam, HIM uses helium ions with energy ranges from 5 to 40 keV. HIM offers a series of advantages compared to SEM such as nanometer and sub-nanometer image resolutions (about 0.35 nm), detailed surface topography, high surface sensitivity, low Z material imaging (especially for polymers and biological samples), high image contrast, and large depth of field. In addition, HIM also has the ability to image insulating materials without any conductive coatings so that surface details are not modified. In this presentation, several scientific applications across biology and geochemistry will be presented to highlight the effectiveness of this powerful microscope. Acknowledgements: Research was performed using the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at PNNL. Work was supported by DOE-BER Mesoscale to Molecules Bioimaging Project FWP# 66382.

Nanometer-sized ceria-coated silica-iron oxide for the reagentless microextraction/preconcentration of heavy metals in environmental and biological samples followed by slurry introduction to ICP-OES.

PubMed

Dados, A; Paparizou, E; Eleftheriou, P; Papastephanou, C; Stalikas, C D

2014-04-01

A slurry suspension sampling technique is developed and optimized for the rapid microextraction of heavy metals and analysis using nanometer-sized ceria-coated silica-iron oxide particles and inductively coupled plasma optical emission spectrometry (ICP-OES). Magnetic-silica material is synthesized by a co-precipitation and sol-gel method followed by ceria coating through a precipitation. The large particles are removed using a sedimentation-fractionation procedure and a magnetic homogeneous colloidal suspension of ceria-modified iron oxide-silica is produced for microextraction. The nanometer-sized particles are separated from the sample solution magnetically and analyzed with ICP-OES using a slurry suspension sampling approach. The ceria-modified iron oxide-silica does not contain any organic matter and this probably justifies the absence of matrix effect on plasma atomization capacity, when increased concentrations of slurries are aspirated. The As, Be, Mo, Cr, Cu, Pb, Hg, Sb, Se and V can be preconcentrated by the proposed method at pH 6.0 while Mn, Cd, Co and Ni require a pH ≥ 8.0. Satisfactory values are obtained for the relative standard deviations (2-6%), recoveries (88-102%), enrichment factors (14-19) and regression correlation coefficients as well as detectability, at sub-μg L(-1) levels. The applicability of magnetic ceria for the microextraction of metal ions in combination with the slurry introduction technique using ICP is substantiated by the analysis of environmental water and urine samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of pathology department Web sites and practical recommendations.

PubMed

Nero, Christopher; Dighe, Anand S

2008-09-01

There are numerous customers for pathology departmental Web sites, including pathology department staff, clinical staff, residency applicants, job seekers, and other individuals outside the department seeking department information. Despite the increasing importance of departmental Web sites as a means of distributing information, no analysis has been done to date of the content and usage of pathology department Web sites. In this study, we analyzed pathology department Web sites to examine the elements present on each site and to evaluate the use of search technology on these sites. Further, we examined the usage patterns of our own departmental Internet and internet Web sites to better understand the users of pathology Web sites. We reviewed selected departmental pathology Web sites and analyzed their content and functionality. Our institution's departmental pathology Web sites were modified to enable detailed information to be stored regarding users and usage patterns, and that information was analyzed. We demonstrate considerable heterogeneity in departmental Web sites with many sites lacking basic content and search features. In addition, we demonstrate that increasing the traffic of a department's informational Web sites may result in reduced phone inquiries to the laboratory. We propose recommendations for pathology department Web sites to maximize promotion of a department's mission. A departmental pathology Web site is an essential communication tool for all pathology departments, and attention to the users and content of the site can have operational impact.

Metal-assisted exfoliation (MAE): green process for transferring graphene to flexible substrates and templating of sub-nanometer plasmonic gaps (Presentation Recording)

NASA Astrophysics Data System (ADS)

Zaretski, Aliaksandr V.; Marin, Brandon C.; Moetazedi, Herad; Dill, Tyler J.; Jibril, Liban; Kong, Casey; Tao, Andrea R.; Lipomi, Darren J.

2015-09-01

This paper describes a new technique, termed "metal-assisted exfoliation," for the scalable transfer of graphene from catalytic copper foils to flexible polymeric supports. The process is amenable to roll-to-roll manufacturing, and the copper substrate can be recycled. We then demonstrate the use of single-layer graphene as a template for the formation of sub-nanometer plasmonic gaps using a scalable fabrication process called "nanoskiving." These gaps are formed between parallel gold nanowires in a process that first produces three-layer thin films with the architecture gold/single-layer graphene/gold, and then sections the composite films with an ultramicrotome. The structures produced can be treated as two gold nanowires separated along their entire lengths by an atomically thin graphene nanoribbon. Oxygen plasma etches the sandwiched graphene to a finite depth; this action produces a sub-nanometer gap near the top surface of the junction between the wires that is capable of supporting highly confined optical fields. The confinement of light is confirmed by surface-enhanced Raman spectroscopy measurements, which indicate that the enhancement of the electric field arises from the junction between the gold nanowires. These experiments demonstrate nanoskiving as a unique and easy-to-implement fabrication technique that is capable of forming sub-nanometer plasmonic gaps between parallel metallic nanostructures over long, macroscopic distances. These structures could be valuable for fundamental investigations as well as applications in plasmonics and molecular electronics.

Towards nanometer-spaced silicon contacts to proteins.

PubMed

Schukfeh, Muhammed I; Sepunaru, Lior; Behr, Pascal; Li, Wenjie; Pecht, Israel; Sheves, Mordechai; Cahen, David; Tornow, Marc

2016-03-18

A vertical nanogap device (VND) structure comprising all-silicon contacts as electrodes for the investigation of electronic transport processes in bioelectronic systems is reported. Devices were fabricated from silicon-on-insulator substrates whose buried oxide (SiO2) layer of a few nanometers in thickness is embedded within two highly doped single crystalline silicon layers. Individual VNDs were fabricated by standard photolithography and a combination of anisotropic and selective wet etching techniques, resulting in p(+) silicon contacts, vertically separated by 4 or 8 nm, depending on the chosen buried oxide thickness. The buried oxide was selectively recess-etched with buffered hydrofluoric acid, exposing a nanogap. For verification of the devices' electrical functionality, gold nanoparticles were successfully trapped onto the nanogap electrodes' edges using AC dielectrophoresis. Subsequently, the suitability of the VND structures for transport measurements on proteins was investigated by functionalizing the devices with cytochrome c protein from solution, thereby providing non-destructive, permanent semiconducting contacts to the proteins. Current-voltage measurements performed after protein deposition exhibited an increase in the junctions' conductance of up to several orders of magnitude relative to that measured prior to cytochrome c immobilization. This increase in conductance was lost upon heating the functionalized device to above the protein's denaturation temperature (80 °C). Thus, the VND junctions allow conductance measurements which reflect the averaged electronic transport through a large number of protein molecules, contacted in parallel with permanent contacts and, for the first time, in a symmetrical Si-protein-Si configuration.

Nanometer scale thermometry in a living cell

PubMed Central

Kucsko, G.; Maurer, P. C.; Yao, N. Y.; Kubo, M.; Noh, H. J.; Lo, P. K.; Park, H.; Lukin, M. D.

2014-01-01

Sensitive probing of temperature variations on nanometer scales represents an outstanding challenge in many areas of modern science and technology1. In particular, a thermometer capable of sub-degree temperature resolution over a large range of temperatures as well as integration within a living system could provide a powerful new tool for many areas of biological, physical and chemical research; possibilities range from the temperature-induced control of gene expression2–5 and tumor metabolism6 to the cell-selective treatment of disease7,8 and the study of heat dissipation in integrated circuits1. By combining local light-induced heat sources with sensitive nanoscale thermometry, it may also be possible to engineer biological processes at the sub-cellular level2–5. Here, we demonstrate a new approach to nanoscale thermometry that utilizes coherent manipulation of the electronic spin associated with nitrogen-vacancy (NV) color centers in diamond. We show the ability to detect temperature variations down to 1.8 mK (sensitivity of 9mK/Hz) in an ultra-pure bulk diamond sample. Using NV centers in diamond nanocrystals (nanodiamonds, NDs), we directly measure the local thermal environment at length scales down to 200 nm. Finally, by introducing both nanodiamonds and gold nanoparticles into a single human embryonic fibroblast, we demonstrate temperature-gradient control and mapping at the sub-cellular level, enabling unique potential applications in life sciences. PMID:23903748

Winding single-molecule double-stranded DNA on a nanometer-sized reel

PubMed Central

You, Huijuan; Iino, Ryota; Watanabe, Rikiya; Noji, Hiroyuki

2012-01-01

A molecular system of a nanometer-sized reel was developed from F1–ATPase, a rotary motor protein. By combination with magnetic tweezers and optical tweezers, single-molecule double-stranded DNA (dsDNA) was wound around the molecular reel. The bending stiffness of dsDNA was determined from the winding tension (0.9–6.0 pN) and the diameter of the wound loop (21.4–8.5 nm). Our results were in good agreement with the conventional worm-like chain model and a persistence length of 54 ± 9 nm was estimated. This molecular reel system offers a new platform for single-molecule study of micromechanics of sharply bent DNA molecules and is expected to be applicable to the elucidation of the molecular mechanism of DNA-associating proteins on sharply bent DNA strands. PMID:22772992

40 CFR 1400.8 - Access to off-site consequence analysis information by Federal government officials.

Code of Federal Regulations, 2011 CFR

2011-07-01

... analysis information by Federal government officials. 1400.8 Section 1400.8 Protection of Environment... INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.8 Access to off-site consequence analysis information by Federal...

40 CFR 1400.8 - Access to off-site consequence analysis information by Federal government officials.

Code of Federal Regulations, 2013 CFR

2013-07-01

... analysis information by Federal government officials. 1400.8 Section 1400.8 Protection of Environment... INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.8 Access to off-site consequence analysis information by Federal...

40 CFR 1400.8 - Access to off-site consequence analysis information by Federal government officials.

Code of Federal Regulations, 2012 CFR

2012-07-01

... analysis information by Federal government officials. 1400.8 Section 1400.8 Protection of Environment... INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.8 Access to off-site consequence analysis information by Federal...

40 CFR 1400.8 - Access to off-site consequence analysis information by Federal government officials.

Code of Federal Regulations, 2014 CFR

2014-07-01

... analysis information by Federal government officials. 1400.8 Section 1400.8 Protection of Environment... INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.8 Access to off-site consequence analysis information by Federal...

VISA--Vector Integration Site Analysis server: a web-based server to rapidly identify retroviral integration sites from next-generation sequencing.

PubMed

Hocum, Jonah D; Battrell, Logan R; Maynard, Ryan; Adair, Jennifer E; Beard, Brian C; Rawlings, David J; Kiem, Hans-Peter; Miller, Daniel G; Trobridge, Grant D

2015-07-07

Analyzing the integration profile of retroviral vectors is a vital step in determining their potential genotoxic effects and developing safer vectors for therapeutic use. Identifying retroviral vector integration sites is also important for retroviral mutagenesis screens. We developed VISA, a vector integration site analysis server, to analyze next-generation sequencing data for retroviral vector integration sites. Sequence reads that contain a provirus are mapped to the human genome, sequence reads that cannot be localized to a unique location in the genome are filtered out, and then unique retroviral vector integration sites are determined based on the alignment scores of the remaining sequence reads. VISA offers a simple web interface to upload sequence files and results are returned in a concise tabular format to allow rapid analysis of retroviral vector integration sites.

Electrolytes in a nanometer slab-confinement: Ion-specific structure and solvation forces

NASA Astrophysics Data System (ADS)

Kalcher, Immanuel; Schulz, Julius C. F.; Dzubiella, Joachim

2010-10-01

We study the liquid structure and solvation forces of dense monovalent electrolytes (LiCl, NaCl, CsCl, and NaI) in a nanometer slab-confinement by explicit-water molecular dynamics (MD) simulations, implicit-water Monte Carlo (MC) simulations, and modified Poisson-Boltzmann (PB) theories. In order to consistently coarse-grain and to account for specific hydration effects in the implicit methods, realistic ion-ion and ion-surface pair potentials have been derived from infinite-dilution MD simulations. The electrolyte structure calculated from MC simulations is in good agreement with the corresponding MD simulations, thereby validating the coarse-graining approach. The agreement improves if a realistic, MD-derived dielectric constant is employed, which partially corrects for (water-mediated) many-body effects. Further analysis of the ionic structure and solvation pressure demonstrates that nonlocal extensions to PB (NPB) perform well for a wide parameter range when compared to MC simulations, whereas all local extensions mostly fail. A Barker-Henderson mapping of the ions onto a charged, asymmetric, and nonadditive binary hard-sphere mixture shows that the strength of structural correlations is strongly related to the magnitude and sign of the salt-specific nonadditivity. Furthermore, a grand canonical NPB analysis shows that the Donnan effect is dominated by steric correlations, whereas solvation forces and overcharging effects are mainly governed by ion-surface interactions. However, steric corrections to solvation forces are strongly repulsive for high concentrations and low surface charges, while overcharging can also be triggered by steric interactions in strongly correlated systems. Generally, we find that ion-surface and ion-ion correlations are strongly coupled and that coarse-grained methods should include both, the latter nonlocally and nonadditive (as given by our specific ionic diameters), when studying electrolytes in highly inhomogeneous situations.

Analysis of biomolecular solvation sites by 3D-RISM theory.

PubMed

Sindhikara, Daniel J; Hirata, Fumio

2013-06-06

We derive, implement, and apply equilibrium solvation site analysis for biomolecules. Our method utilizes 3D-RISM calculations to quickly obtain equilibrium solvent distributions without either necessity of simulation or limits of solvent sampling. Our analysis of these distributions extracts highest likelihood poses of solvent as well as localized entropies, enthalpies, and solvation free energies. We demonstrate our method on a structure of HIV-1 protease where excellent structural and thermodynamic data are available for comparison. Our results, obtained within minutes, show systematic agreement with available experimental data. Further, our results are in good agreement with established simulation-based solvent analysis methods. This method can be used not only for visual analysis of active site solvation but also for virtual screening methods and experimental refinement.

A Nanometer Aerosol Size Analyzer (nASA) for Rapid Measurement of High-concentration Size Distributions

NASA Astrophysics Data System (ADS)

Han, Hee-Siew; Chen, Da-Ren; Pui, David Y. H.; Anderson, Bruce E.

2000-03-01

We have developed a fast-response nanometer aerosol size analyzer (nASA) that is capable of scanning 30 size channels between 3 and 100 nm in a total time of 3 s. The analyzer includes a bipolar charger (Po210), an extended-length nanometer differential mobility analyzer (Nano-DMA), and an electrometer (TSI 3068). This combination of components provides particle size spectra at a scan rate of 0.1 s per channel free of uncertainties caused by response-time-induced smearing. The nASA thus offers a fast response for aerosol size distribution measurements in high-concentration conditions and also eliminates the need for applying a de-smearing algorithm to resulting data. In addition, because of its thermodynamically stable means of particle detection, the nASA is useful for applications requiring measurements over a broad range of sample pressures and temperatures. Indeed, experimental transfer functions determined for the extended-length Nano-DMA using the tandem differential mobility analyzer (TDMA) technique indicate the nASA provides good size resolution at pressures as low as 200 Torr. Also, as was demonstrated in tests to characterize the soot emissions from the J85-GE engine of a T-38 aircraft, the broad dynamic concentration range of the nASA makes it particularly suitable for studies of combustion or particle formation processes. Further details of the nASA performance as well as results from calibrations, laboratory tests and field applications are presented below.

A Nanometer Aerosol Size Analyzer (nASA) for Rapid Measurement of High-Concentration Size Distributions

NASA Technical Reports Server (NTRS)

Han, Hee-Siew; Chen, Da-Ren; Pui, David Y. H.; Anderson, Bruce E.

2001-01-01

We have developed a fast-response Nanometer Aerosol Size Analyzer (nASA) that is capable of scanning 30 size channels between 3 and 100 nm in a total time of 3 seconds. The analyzer includes a bipolar charger (P0210), an extended-length Nanometer Differential Mobility Analyzer (Nano-DMA), and an electrometer (TSI 3068). This combination of components provides particle size spectra at a scan rate of 0.1 second per channel free of uncertainties caused by response-time-induced smearing. The nASA thus offers a fast response for aerosol size distribution measurements in high-concentration conditions and also eliminates the need for applying a de-smearing algorithm to resulting data. In addition, because of its thermodynamically stable means of particle detection, the nASA is useful for applications requiring measurements over a broad range of sample pressures and temperatures. Indeed, experimental transfer functions determined for the extended-length Nano-DMA using the Tandem Differential Mobility Analyzer (TDMA) technique indicate the nASA provides good size resolution at pressures as low as 200 Torr. Also, as was demonstrated in tests to characterize the soot emissions from the J85-GE engine of a T38 aircraft, the broad dynamic concentration range of the nASA makes it particularly suitable for studies of combustion or particle formation processes. Further details of the nASA performance as well as results from calibrations, laboratory tests and field applications are presented.

Surface Landing Site Weather Analysis for Constellation Program

NASA Technical Reports Server (NTRS)

Altino, Karen M.; Burns, K. Lee

2008-01-01

Weather information is an important asset for NASA's Constellation Program in developing the next generation space transportation system to fly to the International Space Station, the Moon and, eventually, to Mars. Weather conditions can affect vehicle safety and performance during multiple mission phases ranging from pre-launch ground processing to landing and recovery operations, including all potential abort scenarios. Meteorological analysis is an important contributor, not only to the development and verification of system design requirements but also to mission planning and active ground operations. Of particular interest are the surface atmospheric conditions at both nominal and abort landing sites for the manned Orion capsule. Weather parameters such as wind, rain, and fog all play critical roles in the safe landing of the vehicle and subsequent crew and vehicle recovery. The Marshall Space Flight Center Natural Environments Branch has been tasked by the Constellation Program with defining the natural environments at potential landing zones. Climatological time series of operational surface weather observations are used to calculate probabilities of occurrence of various sets of hypothetical vehicle constraint thresholds, Data are available for numerous geographical locations such that statistical analysis can be performed for single sites as well as multiple-site network configurations. Results provide statistical descriptions of how often certain weather conditions are observed at the site(s) and the percentage that specified criteria thresholds are matched or exceeded. Outputs are tabulated by month and hour of day to show both seasonal and diurnal variation. This paper will describe the methodology used for data collection and quality control, detail the types of analyses performed, and provide a sample of the results that can be obtained,

Young Adult Capacity Initiative Cross-Site Analysis

ERIC Educational Resources Information Center

Academy for Educational Development, 2012

2012-01-01

This cross-site analysis presents findings about the implementation, impact, and outcomes of the Young Adult Capacity Initiative (YACI), at 13 community-based organizations in New York City. These agencies received technical assistance and small incentive grants from the Fund for the City of New York Youth Development Institute (YDI) to build…

Portable Infrared Laser Spectroscopy for On-site Mycotoxin Analysis.

PubMed

Sieger, Markus; Kos, Gregor; Sulyok, Michael; Godejohann, Matthias; Krska, Rudolf; Mizaikoff, Boris

2017-03-09

Mycotoxins are toxic secondary metabolites of fungi that spoil food, and severely impact human health (e.g., causing cancer). Therefore, the rapid determination of mycotoxin contamination including deoxynivalenol and aflatoxin B 1 in food and feed samples is of prime interest for commodity importers and processors. While chromatography-based techniques are well established in laboratory environments, only very few (i.e., mostly immunochemical) techniques exist enabling direct on-site analysis for traders and manufacturers. In this study, we present MYCOSPEC - an innovative approach for spectroscopic mycotoxin contamination analysis at EU regulatory limits for the first time utilizing mid-infrared tunable quantum cascade laser (QCL) spectroscopy. This analysis technique facilitates on-site mycotoxin analysis by combining QCL technology with GaAs/AlGaAs thin-film waveguides. Multivariate data mining strategies (i.e., principal component analysis) enabled the classification of deoxynivalenol-contaminated maize and wheat samples, and of aflatoxin B 1 affected peanuts at EU regulatory limits of 1250 μg kg -1 and 8 μg kg -1 , respectively.

Portable Infrared Laser Spectroscopy for On-site Mycotoxin Analysis

PubMed Central

Sieger, Markus; Kos, Gregor; Sulyok, Michael; Godejohann, Matthias; Krska, Rudolf; Mizaikoff, Boris

2017-01-01

Mycotoxins are toxic secondary metabolites of fungi that spoil food, and severely impact human health (e.g., causing cancer). Therefore, the rapid determination of mycotoxin contamination including deoxynivalenol and aflatoxin B1 in food and feed samples is of prime interest for commodity importers and processors. While chromatography-based techniques are well established in laboratory environments, only very few (i.e., mostly immunochemical) techniques exist enabling direct on-site analysis for traders and manufacturers. In this study, we present MYCOSPEC - an innovative approach for spectroscopic mycotoxin contamination analysis at EU regulatory limits for the first time utilizing mid-infrared tunable quantum cascade laser (QCL) spectroscopy. This analysis technique facilitates on-site mycotoxin analysis by combining QCL technology with GaAs/AlGaAs thin-film waveguides. Multivariate data mining strategies (i.e., principal component analysis) enabled the classification of deoxynivalenol-contaminated maize and wheat samples, and of aflatoxin B1 affected peanuts at EU regulatory limits of 1250 μg kg−1 and 8 μg kg−1, respectively. PMID:28276454

Portable Infrared Laser Spectroscopy for On-site Mycotoxin Analysis

NASA Astrophysics Data System (ADS)

Sieger, Markus; Kos, Gregor; Sulyok, Michael; Godejohann, Matthias; Krska, Rudolf; Mizaikoff, Boris

2017-03-01

Mycotoxins are toxic secondary metabolites of fungi that spoil food, and severely impact human health (e.g., causing cancer). Therefore, the rapid determination of mycotoxin contamination including deoxynivalenol and aflatoxin B1 in food and feed samples is of prime interest for commodity importers and processors. While chromatography-based techniques are well established in laboratory environments, only very few (i.e., mostly immunochemical) techniques exist enabling direct on-site analysis for traders and manufacturers. In this study, we present MYCOSPEC - an innovative approach for spectroscopic mycotoxin contamination analysis at EU regulatory limits for the first time utilizing mid-infrared tunable quantum cascade laser (QCL) spectroscopy. This analysis technique facilitates on-site mycotoxin analysis by combining QCL technology with GaAs/AlGaAs thin-film waveguides. Multivariate data mining strategies (i.e., principal component analysis) enabled the classification of deoxynivalenol-contaminated maize and wheat samples, and of aflatoxin B1 affected peanuts at EU regulatory limits of 1250 μg kg-1 and 8 μg kg-1, respectively.

Solid-density plasma expansion in intense ultra-short laser irradiation measured on nanometer scale and in real time

NASA Astrophysics Data System (ADS)

Kluge, T.; Metzkes, J.; Pelka, A.; Laso Garcia, A.; Prencipe, I.; Bussmann, M.; Zeil, K.; Schoenherr, T.; Hartley, N.; Gutt, C.; Galtier, E.; Nam, I.; Lee, Hj; McBride, Ee; Glenzer, S.; Huebner, U.; Roedel, C.; Nakatsutsumi, M.; Roedel, M.; Rehwald, M.; Garten, M.; Zacharias, M.; Schramm, U.; Cowan, T. E.

2017-10-01

Small Angle X-ray Scattering (SAXS) is discussed to allow unprecedented direct measurements limited only by the probe X-ray wavelength and duration. Here we present the first direct in-situ measurement of intense short-pulse laser - solid interaction that allows nanometer and high temporal resolution at the same time. A 120 fs laser pulse with energy 1 J was focused on a silicon membrane. The density was probed with an X-ray beam of 49 fs duration by SAXS. Despite prepulses, we can exclude premature bulk expansion. The plasma expansion is triggered only shortly before the main pulse, when an expansion of 10 nm within less than 200 fs was measured. Analysis of scattering patterns allows the first direct verification of numerical simulations. Supported by DOE FWP 100182, SF00515; EC FP7 LASERLAB-EUROPE/CHARPAC (contract 284464); German Federal Ministry of Education and Research (BMBF) under Contract Number 03Z1O511; MG and MZ supported by the European Union's Horizon 2020 No 654220.

Nanometer-resolved chemical analyses of femtosecond laser-induced periodic surface structures on titanium

NASA Astrophysics Data System (ADS)

Kirner, Sabrina V.; Wirth, Thomas; Sturm, Heinz; Krüger, Jörg; Bonse, Jörn

2017-09-01

The chemical characteristics of two different types of laser-induced periodic surface structures (LIPSS), so-called high and low spatial frequency LIPSS (HSFL and LSFL), formed upon irradiation of titanium surfaces by multiple femtosecond laser pulses in air (30 fs, 790 nm, 1 kHz), are analyzed by various optical and electron beam based surface analytical techniques, including micro-Raman spectroscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The latter method was employed in a high-resolution mode being capable of spatially resolving even the smallest HSFL structures featuring spatial periods below 100 nm. In combination with an ion sputtering technique, depths-resolved chemical information of superficial oxidation processes was obtained, revealing characteristic differences between the two different types of LIPSS. Our results indicate that a few tens of nanometer shallow HSFL are formed on top of a ˜150 nm thick graded superficial oxide layer without sharp interfaces, consisting of amorphous TiO2 and partially crystallized Ti2O3. The larger LSFL structures with periods close to the irradiation wavelength originate from the laser-interaction with metallic titanium. They are covered by a ˜200 nm thick amorphous oxide layer, which consists mainly of TiO2 (at the surface) and other titanium oxide species of lower oxidation states underneath.

Controllable surface-plasmon resonance in engineered nanometer epitaxial silicide particles embedded in silicon

NASA Technical Reports Server (NTRS)

Fathauer, R. W.; Ksendzov, A.; Iannelli, J. M.; George, T.

1991-01-01

Epitaxial CoSi2 particles in a single-crystal silicon matrix are grown by molecular-beam epitaxy using a technique that allows nanometer control over particle size in three dimensions. These composite layers exhibit resonant absorption predicted by effective-medium theory. Selection of the height and diameter of disklike particles through a choice of growth conditions allows tailoring of the depolarization factor and hence of the surface-plasmon resonance energy. Resonant absorption from 0.49 to 1.04 eV (2.5 to 1.2 micron) is demonstrated and shown to agree well with values predicted by the Garnett (1904, 1906) theory using the bulk dielectric constants for CoSi2 and Si.

Site term from single-station sigma analysis of S-waves in western Turkey

NASA Astrophysics Data System (ADS)

Akyol, Nihal

2018-05-01

The main aim of this study is to obtain site terms from single-station sigma analysis and to compare them with the site functions resulting from different techniques. The dataset consists of 1764 records from 322 micro- and moderate-size local earthquakes recorded by 29 stations in western Turkey. Median models were derived from S-wave Fourier amplitude spectra for selected 22 frequencies, by utilizing the MLR procedure which performs the maximum likelihood (ML) estimation of mixed models where the fixed effects are treated as random (R) effects with infinite variance. At this stage, b (geometrical spreading coefficient) and Q (quality factor) values were decomposed, simultaneously. The residuals of the median models were examined by utilizing the single-station sigma analysis to obtain the site terms of 29 stations. Sigma for the median models is about 0.422 log10 units and decreases to about 0.308, when the site terms from the single-station sigma analysis were considered (27% reduction). The event-corrected within-event standard deviations for each frequency are rather stable, in the range 0.19-0.23 log10 units with an average value of 0.20 (± 0.01). The site terms from single-station sigma analysis were compared with the site function estimates from the horizontal-to-vertical-spectral-ratio (HVSR) and generalized inversion (INV) techniques by Akyol et al. (2013) and Kurtulmuş and Akyol (2015), respectively. Consistency was observed between the single-station sigma site terms and the INV site transfer functions. The results imply that the single-station sigma analysis could separate the site terms with respect to the median models.

A Versatile Methodology Using Sol-Gel, Supercritical Extraction, and Etching to Fabricate a Nitramine Explosive: Nanometer HNIW

NASA Astrophysics Data System (ADS)

Wang, Yi; Song, Xiaolan; Song, Dan; Jiang, Wei; Liu, Hongying; Li, Fengsheng

2013-01-01

A combinative method with three steps was developed to fabricate HNIW (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtziane) nanoexplosives with the gas anti-solvent (GAS) method improved by introducing a gel frame to limit the overgrowth of recrystallized particles and an acid-assistant to remove the used frame. Forming the mixed gel, by locking the explosive solution into a wet gel whose volume was divided by the networks, was the key for the fabrication. As demonstrated by scanning electron microscopy (SEM) analysis, a log-normal size distribution of nano-HNIW indicated that about 74.4% of the particles had sizes <120 nm and maximum particle size was ∼300 nm. Energy-dispersive X-ray spectroscopy (EDS) and infrared (IR) characterizations showed that the aerogel embedded with nanoexplosive particles was dissolved in hydrochloric acid solution, and the raw ɛ-HNIW was mostly transformed into the α phase (nano-HNIW) during recrystallization. Nano-HNIW exhibited impact and friction sensitivity almost equal to those of raw HNIW, within experimental error. Thermal analysis showed that the decomposition peak temperature decreased by more than 10°C and that the heat release increased by 42.5% when the particle size of HNIW was at the nanometer scale.

High precision and high yield fabrication of dense nanoparticle arrays onto DNA origami at statistically independent binding sites

NASA Astrophysics Data System (ADS)

Takabayashi, Sadao; Klein, William P.; Onodera, Craig; Rapp, Blake; Flores-Estrada, Juan; Lindau, Elias; Snowball, Lejmarc; Sam, Joseph T.; Padilla, Jennifer E.; Lee, Jeunghoon; Knowlton, William B.; Graugnard, Elton; Yurke, Bernard; Kuang, Wan; Hughes, William L.

2014-10-01

High precision, high yield, and high density self-assembly of nanoparticles into arrays is essential for nanophotonics. Spatial deviations as small as a few nanometers can alter the properties of near-field coupled optical nanostructures. Several studies have reported assemblies of few nanoparticle structures with controlled spacing using DNA nanostructures with variable yield. Here, we report multi-tether design strategies and attachment yields for homo- and hetero-nanoparticle arrays templated by DNA origami nanotubes. Nanoparticle attachment yield via DNA hybridization is comparable with streptavidin-biotin binding. Independent of the number of binding sites, >97% site-occupation was achieved with four tethers and 99.2% site-occupation is theoretically possible with five tethers. The interparticle distance was within 2 nm of all design specifications and the nanoparticle spatial deviations decreased with interparticle spacing. Modified geometric, binomial, and trinomial distributions indicate that site-bridging, steric hindrance, and electrostatic repulsion were not dominant barriers to self-assembly and both tethers and binding sites were statistically independent at high particle densities.High precision, high yield, and high density self-assembly of nanoparticles into arrays is essential for nanophotonics. Spatial deviations as small as a few nanometers can alter the properties of near-field coupled optical nanostructures. Several studies have reported assemblies of few nanoparticle structures with controlled spacing using DNA nanostructures with variable yield. Here, we report multi-tether design strategies and attachment yields for homo- and hetero-nanoparticle arrays templated by DNA origami nanotubes. Nanoparticle attachment yield via DNA hybridization is comparable with streptavidin-biotin binding. Independent of the number of binding sites, >97% site-occupation was achieved with four tethers and 99.2% site-occupation is theoretically possible with five

40 CFR 1400.3 - Public access to paper copies of off-site consequence analysis information.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-site consequence analysis information. 1400.3 Section 1400.3 Protection of Environment ENVIRONMENTAL... INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Public Access § 1400.3 Public access to paper copies of off-site consequence analysis information. (a) General. The Administrator and the...

40 CFR 1400.3 - Public access to paper copies of off-site consequence analysis information.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-site consequence analysis information. 1400.3 Section 1400.3 Protection of Environment ENVIRONMENTAL... INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Public Access § 1400.3 Public access to paper copies of off-site consequence analysis information. (a) General. The Administrator and the...

40 CFR 1400.3 - Public access to paper copies of off-site consequence analysis information.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-site consequence analysis information. 1400.3 Section 1400.3 Protection of Environment ENVIRONMENTAL... INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Public Access § 1400.3 Public access to paper copies of off-site consequence analysis information. (a) General. The Administrator and the...

40 CFR 1400.3 - Public access to paper copies of off-site consequence analysis information.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-site consequence analysis information. 1400.3 Section 1400.3 Protection of Environment ENVIRONMENTAL... INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Public Access § 1400.3 Public access to paper copies of off-site consequence analysis information. (a) General. The Administrator and the...

Site-specific O-Glycosylation Analysis of Human Blood Plasma Proteins*

PubMed Central

Hoffmann, Marcus; Marx, Kristina; Reichl, Udo; Wuhrer, Manfred; Rapp, Erdmann

2016-01-01

Site-specific glycosylation analysis is key to investigate structure-function relationships of glycoproteins, e.g. in the context of antigenicity and disease progression. The analysis, though, is quite challenging and time consuming, in particular for O-glycosylated proteins. In consequence, despite their clinical and biopharmaceutical importance, many human blood plasma glycoproteins have not been characterized comprehensively with respect to their O-glycosylation. Here, we report on the site-specific O-glycosylation analysis of human blood plasma glycoproteins. To this end pooled human blood plasma of healthy donors was proteolytically digested using a broad-specific enzyme (Proteinase K), followed by a precipitation step, as well as a glycopeptide enrichment and fractionation step via hydrophilic interaction liquid chromatography, the latter being optimized for intact O-glycopeptides carrying short mucin-type core-1 and -2 O-glycans, which represent the vast majority of O-glycans on human blood plasma proteins. Enriched O-glycopeptide fractions were subjected to mass spectrometric analysis using reversed-phase liquid chromatography coupled online to an ion trap mass spectrometer operated in positive-ion mode. Peptide identity and glycan composition were derived from low-energy collision-induced dissociation fragment spectra acquired in multistage mode. To pinpoint the O-glycosylation sites glycopeptides were fragmented using electron transfer dissociation. Spectra were annotated by database searches as well as manually. Overall, 31 O-glycosylation sites and regions belonging to 22 proteins were identified, the majority being acute-phase proteins. Strikingly, also 11 novel O-glycosylation sites and regions were identified. In total 23 O-glycosylation sites could be pinpointed. Interestingly, the use of Proteinase K proved to be particularly beneficial in this context. The identified O-glycan compositions most probably correspond to mono- and disialylated core-1

Beyond Electronic Brochures: An Analysis of Singapore Primary School Web Sites

ERIC Educational Resources Information Center

Hu, Chun; Soong, Andrew Kheng Fah

2007-01-01

This study aims to investigate how Singapore primary schools use their web sites, what kind of information is contained in the web sites, and how the information is presented. Based on an analysis of 176 primary school web sites, which represent all but one of the country's primary schools, findings indicate that most of Singapore's primary school…

Real-time detection of antibiotic activity by measuring nanometer-scale bacterial deformation

NASA Astrophysics Data System (ADS)

Iriya, Rafael; Syal, Karan; Jing, Wenwen; Mo, Manni; Yu, Hui; Haydel, Shelley E.; Wang, Shaopeng; Tao, Nongjian

2017-12-01

Diagnosing antibiotic-resistant bacteria currently requires sensitive detection of phenotypic changes associated with antibiotic action on bacteria. Here, we present an optical imaging-based approach to quantify bacterial membrane deformation as a phenotypic feature in real-time with a nanometer scale (˜9 nm) detection limit. Using this approach, we found two types of antibiotic-induced membrane deformations in different bacterial strains: polymyxin B induced relatively uniform spatial deformation of Escherichia coli O157:H7 cells leading to change in cellular volume and ampicillin-induced localized spatial deformation leading to the formation of bulges or protrusions on uropathogenic E. coli CFT073 cells. We anticipate that the approach will contribute to understanding of antibiotic phenotypic effects on bacteria with a potential for applications in rapid antibiotic susceptibility testing.

Glomerular anionic site distribution in nonproteinuric rats. A computer-assisted morphometric analysis.

PubMed

Pilia, P A; Swain, R P; Williams, A V; Loadholt, C B; Ainsworth, S K

1985-12-01

The cationic ultrastructural tracer polyethyleneimine (PEI: pI approximately equal to 11.0), binds electrophysically to uniformly spaced discrete electron-dense anionic sites present in the laminae rarae of the rat glomerular basement membrane (GBM), mesangial reflections of the GBM, Bowman's capsule, and tubular basement membranes when administered intravenously. Computer-assisted morphometric analysis of glomerular anionic sites reveals that the maximum concentration of stainable lamina rara externa (lre) sites (21/10,000 A GBM) occurs 60 minutes after PEI injection with a site-site interspacing of 460 A. Lamina rara interna (lri) sites similarly demonstrate a maximum concentration (20/10,000 A GBM) at 60 minutes with a periodicity of 497 A. The concentration and distribution of anionic sites within the lri was irregular in pattern and markedly decreased in number, while the lre possesses an electrical field that is highly regular at all time intervals analyzed (15, 30, 60, 120, 180, 240, and 300 minutes). Immersion and perfusion of renal tissue with PEI reveals additional heavy staining of the epithelial and endothelial cell sialoprotein coatings. PEI appears to bind to glomerular anionic sites reversibly: ie, between 60 and 180 minutes the concentration of stained sites decreases. At 300 minutes, the interspacing once again approaches the 60-minute concentration. This suggests a dynamic turnover or dissociation followed by a reassociation of glomerular negatively charged PEI binding sites. In contrast, morphometric analysis of anionic sites stained with lysozyme and protamine sulfate reveals interspacings of 642 A and 585 A, respectively; in addition, these tracers produce major glomerular ultrastructural alterations and induce transient proteinuria. PEI does not induce proteinuria in rats, nor does it produce glomerular morphologic alterations when ten times the tracer dosage is administered intravenously. These findings indicate that the choice of

Towards nanometer-spaced silicon contacts to proteins

NASA Astrophysics Data System (ADS)

Schukfeh, Muhammed I.; Sepunaru, Lior; Behr, Pascal; Li, Wenjie; Pecht, Israel; Sheves, Mordechai; Cahen, David; Tornow, Marc

2016-03-01

A vertical nanogap device (VND) structure comprising all-silicon contacts as electrodes for the investigation of electronic transport processes in bioelectronic systems is reported. Devices were fabricated from silicon-on-insulator substrates whose buried oxide (SiO2) layer of a few nanometers in thickness is embedded within two highly doped single crystalline silicon layers. Individual VNDs were fabricated by standard photolithography and a combination of anisotropic and selective wet etching techniques, resulting in p+ silicon contacts, vertically separated by 4 or 8 nm, depending on the chosen buried oxide thickness. The buried oxide was selectively recess-etched with buffered hydrofluoric acid, exposing a nanogap. For verification of the devices’ electrical functionality, gold nanoparticles were successfully trapped onto the nanogap electrodes’ edges using AC dielectrophoresis. Subsequently, the suitability of the VND structures for transport measurements on proteins was investigated by functionalizing the devices with cytochrome c protein from solution, thereby providing non-destructive, permanent semiconducting contacts to the proteins. Current-voltage measurements performed after protein deposition exhibited an increase in the junctions’ conductance of up to several orders of magnitude relative to that measured prior to cytochrome c immobilization. This increase in conductance was lost upon heating the functionalized device to above the protein’s denaturation temperature (80 °C). Thus, the VND junctions allow conductance measurements which reflect the averaged electronic transport through a large number of protein molecules, contacted in parallel with permanent contacts and, for the first time, in a symmetrical Si-protein-Si configuration.

Osteomyelitis Treatment with Nanometer-Sized Hydroxyapatite Particles as a Delivery Vehicle for a Ciprofloxacin- Bisphosphonate Conjugate; New Fluoroquinolone-Bisphosphonate Derivatives Show Similar Binding Affinity to Hydroxyapatite and Improved Antibacterial Activity Against Drug-Resistant Pathogens

DTIC Science & Technology

2008-12-01

1 OSTEOMYELITIS TREATMENT WITH NANOMETER-SIZED HYDROXYAPATITE PARTICLES AS A DELIVERY VEHICLE FOR A CIPROFLOXACIN- BISPHOSPHONATE CONJUGATE; NEW...FLUOROQUINOLONE-BISPHOSPHONATE DERIVATIVES SHOW SIMILAR BINDING AFFINITY TO HYDROXYAPATITE AND IMPROVED ANTIBACTERIAL ACTIVITY AGAINST DRUG-RESISTANT...vivo OM model. Current studies contrast two CP homeostatic bone-substitute particles, nanometer-sized hydroxyapatite NanOss™ (Nan), and µ-sized

GIS Toolsets for Planetary Geomorphology and Landing-Site Analysis

NASA Astrophysics Data System (ADS)

Nass, Andrea; van Gasselt, Stephan

2015-04-01

Modern Geographic Information Systems (GIS) allow expert and lay users alike to load and position geographic data and perform simple to highly complex surface analyses. For many applications dedicated and ready-to-use GIS tools are available in standard software systems while other applications require the modular combination of available basic tools to answer more specific questions. This also applies to analyses in modern planetary geomorphology where many of such (basic) tools can be used to build complex analysis tools, e.g. in image- and terrain model analysis. Apart from the simple application of sets of different tools, many complex tasks require a more sophisticated design for storing and accessing data using databases (e.g. ArcHydro for hydrological data analysis). In planetary sciences, complex database-driven models are often required to efficiently analyse potential landings sites or store rover data, but also geologic mapping data can be efficiently stored and accessed using database models rather than stand-alone shapefiles. For landings-site analyses, relief and surface roughness estimates are two common concepts that are of particular interest and for both, a number of different definitions co-exist. We here present an advanced toolset for the analysis of image and terrain-model data with an emphasis on extraction of landing site characteristics using established criteria. We provide working examples and particularly focus on the concepts of terrain roughness as it is interpreted in geomorphology and engineering studies.

Nanometer-Scale Dissection of Chromosomes by Atomic Force Microscopy Combined with Heat-Denaturing Treatment

NASA Astrophysics Data System (ADS)

Tsukamoto, Kazumi; Kuwazaki, Seigo; Yamamoto, Kimiko; Shichiri, Motoharu; Yoshino, Tomoyuki; Ohtani, Toshio; Sugiyama, Shigeru

2006-03-01

We have developed a method for dissecting chromosome fragments with a size of a few hundred nanometers by atomic force microscopy (AFM). By using this method, we demonstrated reproducible dissections of silkworm chromosomes in the pachytene phase. The dissected fragments were successfully recovered on the cantilever tips, as confirmed by fluorescent microscopy using fluorescent stained chromosomes. To recover dissected chromosome fragments from a larger chromosome, such as the human metaphase chromosome of a somatic cell, heat denaturation was found to be effective. Further improvements in this method may lead to a novel tool for isolating valuable genes and/or investigating local genome structures in the near future.

Fabrication of a nanometer thick nitrogen delta doped layer at the sub-surface region of (100) diamond

NASA Astrophysics Data System (ADS)

Chandran, Maneesh; Michaelson, Shaul; Saguy, Cecile; Hoffman, Alon

2016-11-01

In this letter, we report on the proof of a concept of an innovative delta doping technique to fabricate an ensemble of nitrogen vacancy centers at shallow depths in (100) diamond. A nitrogen delta doped layer with a concentration of ˜1.8 × 1020 cm-3 and a thickness of a few nanometers was produced using this method. Nitrogen delta doping was realized by producing a stable nitrogen terminated (N-terminated) diamond surface using the RF nitridation process and subsequently depositing a thin layer of diamond on the N-terminated diamond surface. The concentration of nitrogen on the N-terminated diamond surface and its stability upon exposure to chemical vapor deposition conditions are determined by x-ray photoelectron spectroscopy analysis. The SIMS profile exhibits a positive concentration gradient of 1.9 nm/decade and a negative gradient of 4.2 nm/decade. The proposed method offers a finer control on the thickness of the delta doped layer than the currently used ion implantation and delta doping techniques.

Towards sub-nanometer real-space observation of spin and orbital magnetism at the Fe/MgO interface

PubMed Central

Thersleff, Thomas; Muto, Shunsuke; Werwiński, Mirosław; Spiegelberg, Jakob; Kvashnin, Yaroslav; Hjӧrvarsson, Björgvin; Eriksson, Olle; Rusz, Ján; Leifer, Klaus

2017-01-01

While the performance of magnetic tunnel junctions based on metal/oxide interfaces is determined by hybridization, charge transfer, and magnetic properties at the interface, there are currently only limited experimental techniques with sufficient spatial resolution to directly observe these effects simultaneously in real-space. In this letter, we demonstrate an experimental method based on Electron Magnetic Circular Dichroism (EMCD) that will allow researchers to simultaneously map magnetic transitions and valency in real-space over interfacial cross-sections with sub-nanometer spatial resolution. We apply this method to an Fe/MgO bilayer system, observing a significant enhancement in the orbital to spin moment ratio that is strongly localized to the interfacial region. Through the use of first-principles calculations, multivariate statistical analysis, and Electron Energy-Loss Spectroscopy (EELS), we explore the extent to which this enhancement can be attributed to emergent magnetism due to structural confinement at the interface. We conclude that this method has the potential to directly visualize spin and orbital moments at buried interfaces in magnetic systems with unprecedented spatial resolution. PMID:28338011

Towards sub-nanometer real-space observation of spin and orbital magnetism at the Fe/MgO interface

NASA Astrophysics Data System (ADS)

Thersleff, Thomas; Muto, Shunsuke; Werwiński, Mirosław; Spiegelberg, Jakob; Kvashnin, Yaroslav; Hjӧrvarsson, Björgvin; Eriksson, Olle; Rusz, Ján; Leifer, Klaus

2017-03-01

While the performance of magnetic tunnel junctions based on metal/oxide interfaces is determined by hybridization, charge transfer, and magnetic properties at the interface, there are currently only limited experimental techniques with sufficient spatial resolution to directly observe these effects simultaneously in real-space. In this letter, we demonstrate an experimental method based on Electron Magnetic Circular Dichroism (EMCD) that will allow researchers to simultaneously map magnetic transitions and valency in real-space over interfacial cross-sections with sub-nanometer spatial resolution. We apply this method to an Fe/MgO bilayer system, observing a significant enhancement in the orbital to spin moment ratio that is strongly localized to the interfacial region. Through the use of first-principles calculations, multivariate statistical analysis, and Electron Energy-Loss Spectroscopy (EELS), we explore the extent to which this enhancement can be attributed to emergent magnetism due to structural confinement at the interface. We conclude that this method has the potential to directly visualize spin and orbital moments at buried interfaces in magnetic systems with unprecedented spatial resolution.

Ultralow Damping in Nanometer-Thick Epitaxial Spinel Ferrite Thin Films.

PubMed

Emori, Satoru; Yi, Di; Crossley, Sam; Wisser, Jacob J; Balakrishnan, Purnima P; Khodadadi, Behrouz; Shafer, Padraic; Klewe, Christoph; N'Diaye, Alpha T; Urwin, Brittany T; Mahalingam, Krishnamurthy; Howe, Brandon M; Hwang, Harold Y; Arenholz, Elke; Suzuki, Yuri

2018-06-08

Pure spin currents, unaccompanied by dissipative charge flow, are essential for realizing energy-efficient nanomagnetic information and communications devices. Thin-film magnetic insulators have been identified as promising materials for spin-current technology because they are thought to exhibit lower damping compared with their metallic counterparts. However, insulating behavior is not a sufficient requirement for low damping, as evidenced by the very limited options for low-damping insulators. Here, we demonstrate a new class of nanometer-thick ultralow-damping insulating thin films based on design criteria that minimize orbital angular momentum and structural disorder. Specifically, we show ultralow damping in <20 nm thick spinel-structure magnesium aluminum ferrite (MAFO), in which magnetization arises from Fe 3+ ions with zero orbital angular momentum. These epitaxial MAFO thin films exhibit a Gilbert damping parameter of ∼0.0015 and negligible inhomogeneous linewidth broadening, resulting in narrow half width at half-maximum linewidths of ∼0.6 mT around 10 GHz. Our findings offer an attractive thin-film platform for enabling integrated insulating spintronics.

Flow and evaporation in single micrometer and nanometer scale pipes

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

Velasco, A. E.; Yang, C.; Siwy, Z. S.

2014-07-21

We report measurements of pressure driven flow of fluids entering vacuum through a single pipe of micrometer or nanometer scale diameter. Nanopores were fabricated by etching a single ion track in polymer or mica foils. A calibrated mass spectrometer was used to measure the flow rates of nitrogen and helium through pipes with diameter ranging from 10 μm to 31 nm. The flow of gaseous and liquid nitrogen was studied near 77 K, while the flow of helium was studied from the lambda point (2.18 K) to above the critical point (5.2 K). Flow rates were controlled by changing the pressure drop across the pipemore » in the range 0–31 atm. When the pressure in the pipe reached the saturated vapor pressure, an abrupt flow transition was observed. A simple viscous flow model is used to determine the position of the liquid/vapor interface in the pipe. The observed mass flow rates are consistent with no slip boundary conditions.« less

Mission analysis for cross-site transfer

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

Riesenweber, S.D.; Fritz, R.L.; Shipley, L.E.

1995-11-01

The Mission Analysis Report describes the requirements and constraints associated with the Transfer Waste Function as necessary to support the Manage Tank Waste, Retrieve Waste, and Process Tank Waste Functions described in WHC-SD-WM-FRD-020, Tank Waste Remediation System (TWRS) Functions and Requirements Document and DOE/RL-92-60, Revision 1, TWRS Functions and Requirements Document, March 1994. It further assesses the ability of the ``initial state`` (or current cross-site transfer system) to meet the requirements and constraints.

[The therapeutic effect of nanometer silver impregnated dressing on gunshot wounds after being immersed in brine and tapwater in rabbits].

PubMed

Chen, Bi; Ding, Guo-bin; Tang, Chao-wu

2004-03-22

To investigate the therapeutic effect of nanometer silver impregnated dressing on gunshot wounds after being immersed in brine and tapwater in rabbits. Rabbits were randomly divided into two groups after receiving gunshot wounds in both lower limbs. In group 1, the wounded limbs on the experimental side were immersed in brine for 5 h; in group 2, the wounded limbs on experimental side were immersed in tapwater for 5 h. All the wounds were treated with nanometer silver impregnated dressing on the experimental sides, while those of the control sides were treated with vaseline dressing. Biopsy was done after 30 min and 1, 2, 3, 4, 5 h, respectively. In group 1, the onset of inflammation around the wounds of the experimental sides was delayed, the inflammatory response was less serious, and the wounds were dry with less exudation compared to the controls. The mean healing time of the entry wounds on experimental and control sides was (29.4 +/- 6.6) d and (36.3 +/- 6.0) d (P < 0.01), respectively, and that of the exit wounds on experimental and control sides was (20.1 +/- 6.0) d and (27.3 +/- 5.7) d (P < 0.01), respectively. In group 2, only one of the experimental wounds showed mild inflammation, while all of the control wounds showed serious inflammation with much exudation. The mean healing time of the entry wounds on experimentsides was (13.0 +/- 1.52) d, while that on control sides was (16.0 +/- 3.10) d (P < 0.01). The mean healing time of exit wounds on experimental sides was (11.0 +/- 2.75) d, and those of the control sides was (15.6 +/- 2.85) d (P < 0.01). The nanometer silver impregnated dressing can control infection and accelerate healing in gunshot wounds in rabbits.

Missing Data and Influential Sites: Choice of Sites for Phylogenetic Analysis Can Be As Important As Taxon Sampling and Model Choice

PubMed Central

Shavit Grievink, Liat; Penny, David; Holland, Barbara R.

2013-01-01

Phylogenetic studies based on molecular sequence alignments are expected to become more accurate as the number of sites in the alignments increases. With the advent of genomic-scale data, where alignments have very large numbers of sites, bootstrap values close to 100% and posterior probabilities close to 1 are the norm, suggesting that the number of sites is now seldom a limiting factor on phylogenetic accuracy. This provokes the question, should we be fussy about the sites we choose to include in a genomic-scale phylogenetic analysis? If some sites contain missing data, ambiguous character states, or gaps, then why not just throw them away before conducting the phylogenetic analysis? Indeed, this is exactly the approach taken in many phylogenetic studies. Here, we present an example where the decision on how to treat sites with missing data is of equal importance to decisions on taxon sampling and model choice, and we introduce a graphical method for illustrating this. PMID:23471508

SEMICONDUCTOR TECHNOLOGY: Reduction of proximity effect in fabricating nanometer-spaced nanopillars by two-step exposure

NASA Astrophysics Data System (ADS)

Yang, Zhang; Renping, Zhang; Weihua, Han; Jian, Liu; Xiang, Yang; Ying, Wang; Chian Chiu, Li; Fuhua, Yang

2009-11-01

A two-step exposure method to effectively reduce the proximity effect in fabricating nanometer-spaced nanopillars is presented. In this method, nanopillar patterns on poly-methylmethacrylate (PMMA) were partly cross-linked in the first-step exposure. After development, PMMA between nanopillar patterns was removed, and hence the proximity effect would not take place there in the subsequent exposure. In the second-step exposure, PMMA masks were completely cross-linked to achieve good resistance in inductively coupled plasma etching. Accurate pattern transfer of rows of nanopillars with spacing down to 40 nm was realized on a silicon-on-insulator substrate.

Real-time detection of antibiotic activity by measuring nanometer-scale bacterial deformation.

PubMed

Iriya, Rafael; Syal, Karan; Jing, Wenwen; Mo, Manni; Yu, Hui; Haydel, Shelley E; Wang, Shaopeng; Tao, Nongjian

2017-12-01

Diagnosing antibiotic-resistant bacteria currently requires sensitive detection of phenotypic changes associated with antibiotic action on bacteria. Here, we present an optical imaging-based approach to quantify bacterial membrane deformation as a phenotypic feature in real-time with a nanometer scale (∼9  nm) detection limit. Using this approach, we found two types of antibiotic-induced membrane deformations in different bacterial strains: polymyxin B induced relatively uniform spatial deformation of Escherichia coli O157:H7 cells leading to change in cellular volume and ampicillin-induced localized spatial deformation leading to the formation of bulges or protrusions on uropathogenic E. coli CFT073 cells. We anticipate that the approach will contribute to understanding of antibiotic phenotypic effects on bacteria with a potential for applications in rapid antibiotic susceptibility testing. (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Nanometal particle reagents for sensitive, MEMS based fiber-optic, multi-analyte, immuno-biosensing

NASA Astrophysics Data System (ADS)

Hong, Bin

Integration of nanotechnology to medical diagnostics has brought a new era to public health practice. An excellent example is the utilization of unique optoelectronic properties of nanoparticles to develop highly sensitive biosensing devices for point-of-care (POC) disease diagnosis/prognosis. Fluorophore mediated, immuno-biosensors are important disease detection tools. The property of intra-molecular fluorescence quenching of most fluorophores, however, limits the sensitivity of this type of sensors. A plasmon-rich nanometal particle (NMP) can transfer the lone pair electrons of a fluorophore, which normally participate in the fluorescence self-quenching, to its surface plasmon field, resulting in artificial fluorescence enhancement. The enhancement was found to depend on the metal type, the particle size, the distance between a particle and a fluorophore, and the quantum yield of a fluorophore. Some biocompatible solvents were also found to increase the fluorescence emission efficiency via effective dipole coupling between the fluorophore and the solvent molecule. The application of solvents in inmuno-sensing could additionally improve the fluorescence light retrieval by the conformational change of the protein complexes in solvent. The mixture of the NMP and the solvent, which we defined as nanometal particle reagent (NMPR), provided even higher enhancements. Cardiovascular diseases (CVDs) kill 1 person in every 6 seconds. Among the CVDs, acute myocardial infarction (AMI; commonly known as heart attack) is the most dangerous and time-sensitive killer. A rapid and accurate AMI diagnosis is crucial for saving many lives. For this purpose, a fluorophore mediated, immuno-reaction based, multi-cardiac-marker sensing device was developed, to quantify four myocardium-specific proteins simultaneously, accurately, rapidly, and user-friendly. The four cardiac markers of our choice were myoglobin (MG), C-reactive protein (CRP), cardiac troponin I (cTnI), and B

40 CFR 1400.5 - Internet access to certain off-site consequence analysis data elements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... UNDER THE CLEAN AIR ACT SECTION 112(r)(7); DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Public Access § 1400.5 Internet access to certain off... consequence analysis data elements. 1400.5 Section 1400.5 Protection of Environment ENVIRONMENTAL PROTECTION...

40 CFR 1400.5 - Internet access to certain off-site consequence analysis data elements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... UNDER THE CLEAN AIR ACT SECTION 112(r)(7); DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Public Access § 1400.5 Internet access to certain off... consequence analysis data elements. 1400.5 Section 1400.5 Protection of Environment ENVIRONMENTAL PROTECTION...

40 CFR 1400.5 - Internet access to certain off-site consequence analysis data elements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... UNDER THE CLEAN AIR ACT SECTION 112(r)(7); DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Public Access § 1400.5 Internet access to certain off... consequence analysis data elements. 1400.5 Section 1400.5 Protection of Environment ENVIRONMENTAL PROTECTION...

Sub-Optical Lithography With Nanometer Definition Masks

NASA Technical Reports Server (NTRS)

Hartley, Frank T.; Malek, Chantal Khan; Neogi, Jayant

2000-01-01

Nanometer feature size lithography represents a major paradigm shift for the electronics and micro-electro-mechanical industries. In this paper, we discuss the capacity of dynamic focused reactive ion beam (FIB) etching systems to undertake direct and highly anisotropic erosion of thick evaporated gold coatings on boron-doped silicon X-ray mask membranes. FIB offers a new level of flexibility in micro fabrication, allowing for fast fabrication of X-ray masks, where pattern definition and surface alteration are combined in the same step which eliminates the whole lithographic process, in particular resist, resist development, electro-deposition and resist removal. Focused ion beam diameters as small as 7 nm can be obtained enabling fabrication well into the sub-20 nm regime. In preliminary demonstrations of this X-ray mask fabrication technique 22 nm width lines were milled directly through 0.9 microns of gold and a miniature mass spectrometer pattern was milled through over 0.5 microns of gold. Also presented are the results of the shadow printing, using the large depth of field of synchrotron high energy parallel X-ray beam, of these and other sub-optical defined patterns in photoresist conformally coated over surfaces of extreme topographical variation. Assuming that electronic circuits and/or micro devices scale proportionally, the surface area of devices processed with X-ray lithography and 20 nm critical dimension X-ray masks would be 0.5% that of contemporary devices (350 nm CD). The 20 CD mask fabrication represents an initial effort - a further factor of three reduction is anticipated which represents a further order-of-magnitude reduction in die area.

40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2014 CFR

2014-07-01

... analysis information by State and local government officials. 1400.9 Section 1400.9 Protection of... CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.9 Access to off-site consequence analysis...

40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2011 CFR

2011-07-01

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40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2010 CFR

2010-07-01

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40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2013 CFR

2013-07-01

... analysis information by State and local government officials. 1400.9 Section 1400.9 Protection of... CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.9 Access to off-site consequence analysis...

40 CFR 1400.9 - Access to off-site consequence analysis information by State and local government officials.

Code of Federal Regulations, 2012 CFR

2012-07-01

... analysis information by State and local government officials. 1400.9 Section 1400.9 Protection of... CONSEQUENCE ANALYSIS INFORMATION DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Access to Off-Site Consequence Analysis Information by Government Officials. § 1400.9 Access to off-site consequence analysis...

Drift-insensitive distributed calibration of probe microscope scanner in nanometer range: Virtual mode

NASA Astrophysics Data System (ADS)

Lapshin, Rostislav V.

2016-08-01

A method of distributed calibration of a probe microscope scanner is suggested. The main idea consists in a search for a net of local calibration coefficients (LCCs) in the process of automatic measurement of a standard surface, whereby each point of the movement space of the scanner can be characterized by a unique set of scale factors. Feature-oriented scanning (FOS) methodology is used as a basis for implementation of the distributed calibration permitting to exclude in situ the negative influence of thermal drift, creep and hysteresis on the obtained results. Possessing the calibration database enables correcting in one procedure all the spatial systematic distortions caused by nonlinearity, nonorthogonality and spurious crosstalk couplings of the microscope scanner piezomanipulators. To provide high precision of spatial measurements in nanometer range, the calibration is carried out using natural standards - constants of crystal lattice. One of the useful modes of the developed calibration method is a virtual mode. In the virtual mode, instead of measurement of a real surface of the standard, the calibration program makes a surface image ;measurement; of the standard, which was obtained earlier using conventional raster scanning. The application of the virtual mode permits simulation of the calibration process and detail analysis of raster distortions occurring in both conventional and counter surface scanning. Moreover, the mode allows to estimate the thermal drift and the creep velocities acting while surface scanning. Virtual calibration makes possible automatic characterization of a surface by the method of scanning probe microscopy (SPM).

Figuring large optics at the sub-nanometer level: compensation for coating and gravity distortions.

PubMed

Gensemer, Stephen; Gross, Mark

2015-11-30

Large, precision optics can now be manufactured with surface figures specified at the sub-nanometer level. However, coatings and gravity deform large optics, and there are limits to what can be corrected by clever compensation. Instead, deformations caused by stress from optical mounts and deposited coatings must be incorporated into the optical design. We demonstrate compensation of coating stress on a 370mm substrate to λ/200 by a process of coating and annealing. We also model the same process and identify the leading effects that must be anticipated in fabrication of optics for future gravitational wave detectors and other applications of large, precisely figured optics, and identify the limitations inherent in using coatings to compensate for these deformations.

Sub-nanometer glass surface dynamics induced by illumination

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

Nguyen, Duc; Nienhaus, Lea; Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801

2015-06-21

Illumination is known to induce stress and morphology changes in opaque glasses. Amorphous silicon carbide (a-SiC) has a smaller bandgap than the crystal. Thus, we were able to excite with 532 nm light a 1 μm amorphous surface layer on a SiC crystal while recording time-lapse movies of glass surface dynamics by scanning tunneling microscopy (STM). Photoexcitation of the a-SiC surface layer through the transparent crystal avoids heating the STM tip. Up to 6 × 10{sup 4} s, long movies of surface dynamics with 40 s time resolution and sub-nanometer spatial resolution were obtained. Clusters of ca. 3-5 glass formingmore » units diameter are seen to cooperatively hop between two states at the surface. Photoexcitation with green laser light recruits immobile clusters to hop, rather than increasing the rate at which already mobile clusters hop. No significant laser heating was observed. Thus, we favor an athermal mechanism whereby electronic excitation of a-SiC directly controls glassy surface dynamics. This mechanism is supported by an exciton migration-relaxation-thermal diffusion model. Individual clusters take ∼1 h to populate states differently after the light intensity has changed. We believe the surrounding matrix rearranges slowly when it is stressed by a change in laser intensity, and clusters serve as a diagnostic. Such cluster hopping and matrix rearrangement could underlie the microscopic mechanism of photoinduced aging of opaque glasses.« less

Analysis of ILRS Site Ties

NASA Astrophysics Data System (ADS)

Husson, V. S.; Long, J. L.; Pearlman, M.

2001-12-01

By the end of 2000, 94% of ILRS stations had completed station and site information forms (i.e. site logs). These forms contain six types of information. These six categories include site identifiers, contact information, approximate coordinates, system configuration history, system ranging capabilities, and local survey ties. The ILRS Central Bureau, in conjunction with the ILRS Networks and Engineering Working Group, has developed procedures to quality control site log contents. Part of this verification entails data integrity checks of local site ties and is the primary focus of this paper. Local survey ties are critical to the combination of space geodetic network coordinate solutions (i.e. GPS, SLR, VLBI, DORIS) of the International Terrestrial Reference Frame (ITRF). Approximately 90% of active SLR sites are collocated with at least one other space geodetic technique. The process used to verify these SLR ties, at collocated sites, is identical to the approach used in ITRF2000. Local vectors (X, Y, Z) from each ILRS site log are differenced from its corresponding ITRF2000 position vectors (i.e. no transformations). These X, Y, and Z deltas are converted into North, East, and Up. Any deltas, in any component, larger than 5 millimeter is flagged for investigation. In the absence of ITRF2000 SLR positions, CSR positions were used. To further enhance this comparison and to fill gaps in information, local ties contained in site logs from the other space geodetic services (i.e. IGS, IVS, IDS) were used in addition to ITRF2000 ties. Case studies of two collocated sites (McDonald/Ft. Davis and Hartebeeshtoek) will be explored in-depth. Recommendations on how local site surveys should be conducted and how this information should be managed will also be presented.

Analysis of the geomorphology surrounding the Chang'e-3 landing site

NASA Astrophysics Data System (ADS)

Li, Chun-Lai; Mu, Ling-Li; Zou, Xiao-Duan; Liu, Jian-Jun; Ren, Xin; Zeng, Xing-Guo; Yang, Yi-Man; Zhang, Zhou-Bin; Liu, Yu-Xuan; Zuo, Wei; Li, Han

2014-12-01

Chang'e-3 (CE-3) landed on the Mare Imbrium basin in the east part of Sinus Iridum (19.51°W, 44.12°N), which was China's first soft landing on the Moon and it started collecting data on the lunar surface environment. To better understand the environment of this region, this paper utilizes the available high-resolution topography data, image data and geological data to carry out a detailed analysis and research on the area surrounding the landing site (Sinus Iridum and 45 km×70 km of the landing area) as well as on the topography, landform, geology and lunar dust of the area surrounding the landing site. A general topographic analysis of the surrounding area is based on a digital elevation model and digital elevation model data acquired by Chang'e-2 that have high resolution; the geology analysis is based on lunar geological data published by USGS; the study on topographic factors and distribution of craters and rocks in the surrounding area covering 4 km×4 km or even smaller is based on images from the CE-3 landing camera and images from the topographic camera; an analysis is done of the effect of the CE-3 engine plume on the lunar surface by comparing images before and after the landing using data from the landing camera. A comprehensive analysis of the results shows that the landing site and its surrounding area are identified as typical lunar mare with flat topography. They are suitable for maneuvers by the rover, and are rich in geological phenomena and scientific targets, making it an ideal site for exploration.

Impact of Nanometer Graphite Addition on the Anti-deliquescence and Tribological Properties of Ni/MoS2 Lubricating Coating

NASA Astrophysics Data System (ADS)

Zhang, S.; Li, G. L.; Wang, H. D.; Xu, B. S.; Ma, G. Z.

In order to improve the long-standing problem of MoS2 coating that lubrication performance drop dramatic after storage in humid air, using nano-composite electro brush plating technology and Ni/MoS2-C combination coating with thinness of 100 μm was succeed deposited on GCr15 substrate. Microstructure, surface morphology and elements of this composite coating were analyzed using SEM, XPS and TEM while phase structure was tested by XRD. The tribological properties of this composite coating were tested by MSTS-1; Test the preceding tribological properties of Ni/MoS2-C composite coatings to the pure Ni/MoS2 after different period storage at room temperature and 100% relative humidity atmosphere of 12 h, 24 h, and 48 h as well as the element of the chemical changes. Research shows that there is a small amount of MoS2 in pure MoS2 coatings behind a 12 hours storage in humid air became MoO3 and the tribological performance decreased significantly followed, in the same conditions composite coating with nanometer graphite addition get a preferably tribological properties while the hardness of this coating was improved by the nanometer graphite addition and combination plating showed a well duration tribological properties as a result.

Sentiment Analysis of Web Sites Related to Vaginal Mesh Use in Pelvic Reconstructive Surgery.

PubMed

Hobson, Deslyn T G; Meriwether, Kate V; Francis, Sean L; Kinman, Casey L; Stewart, J Ryan

2018-05-02

The purpose of this study was to utilize sentiment analysis to describe online opinions toward vaginal mesh. We hypothesized that sentiment in legal Web sites would be more negative than that in medical and reference Web sites. We generated a list of relevant key words related to vaginal mesh and searched Web sites using the Google search engine. Each unique uniform resource locator (URL) was sorted into 1 of 6 categories: "medical", "legal", "news/media", "patient generated", "reference", or "unrelated". Sentiment of relevant Web sites, the primary outcome, was scored on a scale of -1 to +1, and mean sentiment was compared across all categories using 1-way analysis of variance. Tukey test evaluated differences between category pairs. Google searches of 464 unique key words resulted in 11,405 URLs. Sentiment analysis was performed on 8029 relevant URLs (3472 legal, 1625 "medical", 1774 "reference", 666 "news media", 492 "patient generated"). The mean sentiment for all relevant Web sites was +0.01 ± 0.16; analysis of variance revealed significant differences between categories (P < 0.001). Web sites categorized as "legal" and "news/media" had a slightly negative mean sentiment, whereas those categorized as "medical," "reference," and "patient generated" had slightly positive mean sentiments. Tukey test showed differences between all category pairs except the "medical" versus "reference" in comparison with the largest mean difference (-0.13) seen in the "legal" versus "reference" comparison. Web sites related to vaginal mesh have an overall mean neutral sentiment, and Web sites categorized as "medical," "reference," and "patient generated" have significantly higher sentiment scores than related Web sites in "legal" and "news/media" categories.

SUN: A fully automated interferometric test bench aimed at measuring photolithographic grade lenses with a sub nanometer accuracy

NASA Astrophysics Data System (ADS)

Bourgois, R.; Hamy, A. L.; Pourcelot, P.

2017-10-01

SUN is a test bench developed by Safran Reosc to measure spherical or aspherical surface errors of litho-grade lenses with sub-nanometer accuracy. SUN provides full aperture high resolution interferometric measurements. Measurements are performed at the center of curvature using high precision transmission sphere (TS), and Computer Generated Holograms (CGH) for aspheres, in order to light the surface at normal incidence. SUN can measure lenses with diameter up to 350mm and a radius of curvature varying from 60 to 3000 mm.

Split Bull's eye shaped aluminum antenna for plasmon-enhanced nanometer scale germanium photodetector.

PubMed

Ren, Fang-Fang; Ang, Kah-Wee; Ye, Jiandong; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

2011-03-09

Bull's eye antennas are capable of efficiently collecting and concentrating optical signals into an ultrasmall area, offering an excellent solution to break the bottleneck between speed and photoresponse in subwavelength photodetectors. Here, we exploit the idea of split bull's eye antenna for a nanometer germanium photodetector operating at a standard communication wavelength of 1310 nm. The nontraditional plasmonic metal aluminum has been implemented in the resonant antenna structure fabricated by standard complementary metal-oxide-semiconductor (CMOS) processing. A significant enhancement in photoresponse could be achieved over the conventional bull's eye scheme due to an increased optical near-field in the active region. Moreover, with this novel antenna design the effective grating area could be significantly reduced without sacrificing device performance. This work paves the way for the future development of low-cost, high-density, and high-speed CMOS-compatible germanium-based optoelectronic devices.

40 CFR 60.1115 - What is a siting analysis?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What is a siting analysis? 60.1115 Section 60.1115 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... unit affects ambient air quality, visibility, soils, vegetation, and other relevant factors. The...

A content analysis of Web sites promoting smoking culture and lifestyle.

PubMed

Ribisl, Kurt M; Lee, Rebecca E; Henriksen, Lisa; Haladjian, Harry H

2003-02-01

The present study examined smoking culture and lifestyle Web sites listed on Yahoo!, a popular Internet search catalog, to determine whether the sites were easily accessible to youth, featured age or health warnings, and mentioned specific tobacco brands. A content analysis of photographs on these sites assessed the demographics of individuals depicted and the amount of smoking and nudity in the photographs. The sample included 30 Web sites, all of which were accessible to youth and did not require age verification services to enter them. Cigarette brand names were mentioned in writing on 35% of the sites, and brand images were present on 24% of the sites. Nearly all of the photographs (95%) depicted smoking, 92% featured women, and 7% contained partial or full nudity. These results underscore the need for greater research and monitoring of smoking-related Internet content by health educators and tobacco control advocates.

In vivo detection of nanometer-scale structural changes of the human tympanic membrane in otitis media.

PubMed

Dsouza, Roshan; Won, Jungeun; Monroy, Guillermo L; Hill, Malcolm C; Porter, Ryan G; Novak, Michael A; Boppart, Stephen A

2018-06-08

Otitis media (OM) is a common ear infection and a leading cause of conductive hearing loss in the pediatric population. Current technologies such as otoscopy, pneumatic otoscopy, tympanometry, and acoustic reflectometry are used to diagnose OM, which can reasonably diagnose the infection with a sensitivity and specificity of 50-90% and 60-90%, respectively. However, these techniques provide limited information about the physical architecture of the tympanic membrane (TM), or what may lie behind it. Here, we report the detection of nanometer-scale structural changes of the TM using nano-sensitive optical coherence tomography (nsOCT). In total, an image dataset from 65 pediatric subjects from three different groups (normal, acute OM, and chronic OM) and with longitudinal image-based analysis of ear infections were included in this study. The nsOCT data were correlated with physician diagnosis and with OCT thickness measurements and were found to be in good agreement with these results. We report that nsOCT detects in vivo structural deformations of the TM earlier than OCT alone, and enhances the detection sensitivity of OCT measurements. This unique technique for early detection of nano-scale structural modifications in the TM has the potential to aid in our understanding of microbiological effects, and possibly for early diagnosis and more effective treatment of OM.

Instantaneous polarization analysis of ambient noise recordings in site response investigations

NASA Astrophysics Data System (ADS)

Del Gaudio, Vincenzo

2017-07-01

A new procedure is proposed for analyses of ambient noise aimed at investigating complex cases of site response to seismic shaking. Information on site response characterized by several resonance frequencies and by amplifications varying with direction can be obtained by analysing instantaneous polarization properties of ambient noise recordings. Through this kind of analysis, it is possible to identify Rayleigh wave packets emerging from incoherent background noise for very short intervals. Analysing noise recordings passed through narrow-band filters with different central frequencies, variations of Rayleigh wave properties depending on frequencies can be estimated. In particular, one can calculate: (i) the instantaneous ratios H/V between the amplitudes of horizontal and vertical components of the elliptical particle motion and (ii) the azimuthal direction of the vertical plane containing such a motion. These can be determined on a large number of recording samples, providing the basis for statistical estimates. A preferential concentration of H/V peak values at site-specific frequencies and directions can reveal directional resonance phenomena. Furthermore, peak amplitudes can be related to site amplification factors and provide constraints for subsurface velocity modelling. Some tests, carried out on data acquired at sites with known response properties, gave indications on how to select the parameters of the analysis that optimize its implementation. In particular, preliminary trials, conducted on a limited number of frequencies, allow the selection of the parameters that, while providing a large number of instantaneous H/V estimates for Rayleigh waves, minimize their scattering. The analysis can then be refined and an H/V curve as function of frequency can be obtained with a higher spectral resolution. First tests showed that cases of directional resonance can be more effectively recognized with this technique and more details can be revealed on its

Designing artificial 2D crystals with site and size controlled quantum dots.

PubMed

Xie, Xuejun; Kang, Jiahao; Cao, Wei; Chu, Jae Hwan; Gong, Yongji; Ajayan, Pulickel M; Banerjee, Kaustav

2017-08-30

Ordered arrays of quantum dots in two-dimensional (2D) materials would make promising optical materials, but their assembly could prove challenging. Here we demonstrate a scalable, site and size controlled fabrication of quantum dots in monolayer molybdenum disulfide (MoS 2 ), and quantum dot arrays with nanometer-scale spatial density by focused electron beam irradiation induced local 2H to 1T phase change in MoS 2 . By designing the quantum dots in a 2D superlattice, we show that new energy bands form where the new band gap can be controlled by the size and pitch of the quantum dots in the superlattice. The band gap can be tuned from 1.81 eV to 1.42 eV without loss of its photoluminescence performance, which provides new directions for fabricating lasers with designed wavelengths. Our work constitutes a photoresist-free, top-down method to create large-area quantum dot arrays with nanometer-scale spatial density that allow the quantum dots to interfere with each other and create artificial crystals. This technique opens up new pathways for fabricating light emitting devices with 2D materials at desired wavelengths. This demonstration can also enable the assembly of large scale quantum information systems and open up new avenues for the design of artificial 2D materials.

Three hundred and eight nanometer excimer light therapy for alopecia universalis that is resistant to other treatments: A clinical study of 11 patients.

PubMed

Arakawa, Yukiyasu; Nomiyama, Tomoko; Katoh, Norito

2016-12-01

Three hundred and eight nanometer excimer light therapy has recently been reported to be effective against patchy alopecia areata (AA) in several clinical studies. However, these studies only included a few patients with severe forms of AA, and all of them exhibited poor outcomes. We further investigated the use of excimer light as a therapeutic option for cases of alopecia universalis (AU) that are resistant to other treatments. Eleven treatment-resistant AU patients were treated with a 308-nm excimer light at 2-week intervals for more than 16 sessions. Four patients achieved good responses and two patients exhibited poor responses. Three patients had Japanese skin type 1 and all of them achieved good responses. The radiation dose was increased until the patients exhibited marked erythema. The patients with Japanese skin type 3 who achieved good responses exhibited strong pigmentation at the irradiated sites. In conclusion, 308-nm excimer light therapy has significant effects on some AU patients who are resistant to other treatments and may be an alternative therapeutic option for AU. During the treatment of AU, high doses of radiation should be administrated until a strong inflammatory skin reaction is seen. © 2016 Japanese Dermatological Association.

Environmental analysis of the operation of Oak Ridge National Laboratory (X-10 site)

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

Boyle, J.W.; Blumberg, R.; Cotter, S.J.

1982-11-01

An environmental analysis of the operation of the Oak Ridge National Laboratory (ORNL) facilities in Bethel Valley and Melton Valley was conducted to present to the public information concerning the extent to which recognizable effects, or potential effects, on the environment may occur. The analysis addresses current operations of the ORNL X-10 site and completed operations that may continue to have residual effects. Solid wastes from ORNL operations at the Y-12 site which are transported to the X-10 site for burial (e.g., Biology Division animal wastes) are included as part of X-10 site operation. Socioeconomic effects are associated primarily withmore » the communities where employees live and with the Knoxville Bureau of Economic Analysis economic area as a whole. Therefore, ORNL employees at both Y-12 and X-10 sites are included in the ORNL socioeconomic impact analysis. An extensive base of environmental data was accumulated for this report. Over 80 reports related to ORNL facilities and/or operations are cited as well as many open-literature citations. Environmental effects of the operation of ORNL result from operational discharges from the onsite facilities; construction and/or modification of facilities, transportation to and from the site of persons, goods and services; socioeconomic impacts to the local, regional, and general population; and accidental discharges if they should occur. Operational discharges to the environnment are constrained by federal, state, and local regulations and by criteria established by the US Department of Energy to minimize adverse impacts. It is the purpose of this document to evaluate the operation of the ORNL insofar as impacts beyond the site boundary may occur or have the potential for occurrence.« less

First On-Site Data Analysis System for Subaru/Suprime-Cam

NASA Astrophysics Data System (ADS)

Furusawa, Hisanori; Okura, Yuki; Mineo, Sogo; Takata, Tadafumi; Nakata, Fumiaki; Tanaka, Manobu; Katayama, Nobuhiko; Itoh, Ryosuke; Yasuda, Naoki; Miyazaki, Satoshi; Komiyama, Yutaka; Utsumi, Yousuke; Uchida, Tomohisa; Aihara, Hiroaki

2011-03-01

We developed an automated on-site quick analysis system for mosaic CCD data of Suprime-Cam, which is a wide-field camera mounted at the prime focus of the Subaru Telescope, Mauna Kea, Hawaii. The first version of the data-analysis system was constructed, and started to operate in general observations. This system is a new function of observing support at the Subaru Telescope to provide the Subaru user community with an automated on-site data evaluation, aiming at improvements of observers' productivity, especially in large imaging surveys. The new system assists the data evaluation tasks in observations by the continuous monitoring of the characteristics of every data frame during observations. The evaluation results and data frames processed by this system are also useful for reducing the data-processing time in a full analysis after an observation. The primary analysis functions implemented in the data-analysis system are composed of automated realtime analysis for data evaluation and on-demand analysis, which is executed upon request, including mosaicing analysis and flat making analysis. In data evaluation, which is controlled by the organizing software, the database keeps track of the analysis histories, as well as the evaluated values of data frames, including seeing and sky background levels; it also helps in the selection of frames for mosaicing and flat making analysis. We examined the system performance and confirmed an improvement in the data-processing time by a factor of 9 with the aid of distributed parallel data processing and on-memory data processing, which makes the automated data evaluation effective.

Combining stakeholder analysis and spatial multicriteria evaluation to select and rank inert landfill sites.

PubMed

Geneletti, Davide

2010-02-01

This paper presents a method based on the combination of stakeholder analysis and spatial multicriteria evaluation (SMCE) to first design possible sites for an inert landfill, and then rank them according to their suitability. The method was tested for the siting of an inert landfill in the Sarca's Plain, located in south-western Trentino, an alpine region in northern Italy. Firstly, stakeholder analysis was conducted to identify a set of criteria to be satisfied by new inert landfill sites. SMCE techniques were then applied to combine the criteria, and obtain a suitability map of the study region. Subsequently, the most suitable sites were extracted by taking into account also thresholds based on size and shape. These sites were then compared and ranked according to their visibility, accessibility and dust pollution. All these criteria were assessed through GIS modelling. Sensitivity analyses were performed on the results to assess the stability of the ranking with respect to variations in the input (criterion scores and weights). The study concluded that the three top-ranking sites are located close to each other, in the northernmost sector of the study area. A more general finding was that the use of different criteria in the different stages of the analysis allowed to better differentiate the suitability of the potential landfill sites.

Preparation and properties of nanometer silk fibroin peptide/polyvinyl alcohol blend films for cell growth.

PubMed

Luo, Qin; Chen, Zhongmin; Hao, Xuefei; Zhu, Qiangsong; Zhou, Yucheng

2013-10-01

Nanometer silk fibroin peptide (Nano-SFP) was prepared from silkworm cocoons through the process of dissolution, dialysis and enzymolysis. For comparison, silk fibroin was decomposed with α-chymotrypsin, trypsin and neutrase, respectively. From the SEM and particle size analysis results, the Nano-SFP prepared by neutrase was found to be the most desirable at about 50-200 nm. Nano-SFP/polyvinyl alcohol films (Nano-SFP/PVA) were prepared by blending Nano-SFP and PVA in water with different weight ratios of 10/90, 20/80, 30/70, and 40/60. The films were characterized by IR, SEM, TG, DSC and tensile strength test for investigating their structure, surface morphology, thermostability, and mechanical property. The results showed that Nano-SFP inserted in the PVA films with small linear particles, and Nano-SFP/PVA films exhibited smooth surface, good thermostability and tensile strength. The growth of Chinese hamster ovary (CHO) cells on films with and without Nano-SFP was investigated with MTT colorimetric assay to assess the films' ability to promote cell growth. It was observed that the Nano-SFP improved cell adhesion on the film surface, and the ability of promoting cell growth increased with the increasing content of Nano-SFP in the blend films. Nano-SFP/PVA film with the ratio of 30/70 was concluded to have the best properties. Copyright © 2013 Elsevier B.V. All rights reserved.

40 CFR 60.4805 - What is a siting analysis?

Code of Federal Regulations, 2011 CFR

2011-07-01

... impacts that are prepared to comply with state, local, or other Federal regulatory requirements may be... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What is a siting analysis? 60.4805 Section 60.4805 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

Case-control analysis in highway safety: Accounting for sites with multiple crashes.

PubMed

Gross, Frank

2013-12-01

There is an increased interest in the use of epidemiological methods in highway safety analysis. The case-control and cohort methods are commonly used in the epidemiological field to identify risk factors and quantify the risk or odds of disease given certain characteristics and factors related to an individual. This same concept can be applied to highway safety where the entity of interest is a roadway segment or intersection (rather than a person) and the risk factors of interest are the operational and geometric characteristics of a given roadway. One criticism of the use of these methods in highway safety is that they have not accounted for the difference between sites with single and multiple crashes. In the medical field, a disease either occurs or it does not; multiple occurrences are generally not an issue. In the highway safety field, it is necessary to evaluate the safety of a given site while accounting for multiple crashes. Otherwise, the analysis may underestimate the safety effects of a given factor. This paper explores the use of the case-control method in highway safety and two variations to account for sites with multiple crashes. Specifically, the paper presents two alternative methods for defining cases in a case-control study and compares the results in a case study. The first alternative defines a separate case for each crash in a given study period, thereby increasing the weight of the associated roadway characteristics in the analysis. The second alternative defines entire crash categories as cases (sites with one crash, sites with two crashes, etc.) and analyzes each group separately in comparison to sites with no crashes. The results are also compared to a "typical" case-control application, where the cases are simply defined as any entity that experiences at least one crash and controls are those entities without a crash in a given period. In a "typical" case-control design, the attributes associated with single-crash segments are weighted

The Global Oscillation Network Group site survey. 1: Data collection and analysis methods

NASA Technical Reports Server (NTRS)

Hill, Frank; Fischer, George; Grier, Jennifer; Leibacher, John W.; Jones, Harrison B.; Jones, Patricia P.; Kupke, Renate; Stebbins, Robin T.

1994-01-01

The Global Oscillation Network Group (GONG) Project is planning to place a set of instruments around the world to observe solar oscillations as continuously as possible for at least three years. The Project has now chosen the sites that will comprise the network. This paper describes the methods of data collection and analysis that were used to make this decision. Solar irradiance data were collected with a one-minute cadence at fifteen sites around the world and analyzed to produce statistics of cloud cover, atmospheric extinction, and transparency power spectra at the individual sites. Nearly 200 reasonable six-site networks were assembled from the individual stations, and a set of statistical measures of the performance of the networks was analyzed using a principal component analysis. An accompanying paper presents the results of the survey.

Three-dimensional nanometer scale analyses of precipitate structures and local compositions in titanium aluminide engineering alloys

NASA Astrophysics Data System (ADS)

Gerstl, Stephan S. A.

Titanium aluminide (TiAl) alloys are among the fastest developing class of materials for use in high temperature structural applications. Their low density and high strength make them excellent candidates for both engine and airframe applications. Creep properties of TiAl alloys, however, have been a limiting factor in applying the material to a larger commercial market. In this research, nanometer scale compositional and structural analyses of several TiAl alloys, ranging from model Ti-Al-C ternary alloys to putative commercial alloys with 10 components are investigated utilizing three dimensional atom probe (3DAP) and transmission electron microscopies. Nanometer sized borides, silicides, and carbide precipitates are involved in strengthening TiAl alloys, however, chemical partitioning measurements reveal oxygen concentrations up to 14 at. % within the precipitate phases, resulting in the realization of oxycarbide formation contributing to the precipitation strengthening of TiAl alloys. The local compositions of lamellar microstructures and a variety of precipitates in the TiAl system, including boride, silicide, binary carbides, and intermetallic carbides are investigated. Chemical partitioning of the microalloying elements between the alpha2/gamma lamellar phases, and the precipitate/gamma-matrix phases are determined. Both W and Hf have been shown to exhibit a near interfacial excess of 0.26 and 0.35 atoms nm-2 respectively within ca. 7 nm of lamellar interfaces in a complex TiAl alloy. In the case of needle-shaped perovskite Ti3AlC carbide precipitates, periodic domain boundaries are observed 5.3+/-0.8 nm apart along their growth axis parallel to the TiAl[001] crystallographic direction with concomitant composition variations after 24 hrs. at 800°C.

Inadvertent Intruder Analysis For The Portsmouth On-Site Waste Disposal Facility (OSWDF)

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

Smith, Frank G.; Phifer, Mark A.

2014-01-22

The inadvertent intruder analysis considers the radiological impacts to hypothetical persons who are assumed to inadvertently intrude on the Portsmouth OSWDF site after institutional control ceases 100 years after site closure. For the purposes of this analysis, we assume that the waste disposal in the OSWDF occurs at time zero, the site is under institutional control for the next 100 years, and inadvertent intrusion can occur over the following 1,000 year time period. Disposal of low-level radioactive waste in the OSWDF must meet a requirement to assess impacts on such individuals, and demonstrate that the effective dose equivalent to anmore » intruder would not likely exceed 100 mrem per year for scenarios involving continuous exposure (i.e. chronic) or 500 mrem for scenarios involving a single acute exposure. The focus in development of exposure scenarios for inadvertent intruders was on selecting reasonable events that may occur, giving consideration to regional customs and construction practices. An important assumption in all scenarios is that an intruder has no prior knowledge of the existence of a waste disposal facility at the site. Results of the analysis show that a hypothetical inadvertent intruder at the OSWDF who, in the worst case scenario, resides on the site and consumes vegetables from a garden established on the site using contaminated soil (chronic agriculture scenario) would receive a maximum chronic dose of approximately 7.0 mrem/yr during the 1000 year period of assessment. This dose falls well below the DOE chronic dose limit of 100 mrem/yr. Results of the analysis also showed that a hypothetical inadvertent intruder at the OSWDF who, in the worst case scenario, excavates a basement in the soil that reaches the waste (acute basement construction scenario) would receive a maximum acute dose of approximately 0.25 mrem/yr during the 1000 year period of assessment. This dose falls well below the DOE acute dose limit of 500 mrem/yr. Disposal

40 CFR 60.2050 - What is a siting analysis?

Code of Federal Regulations, 2010 CFR

2010-07-01

... alternatives. (b) Analyses of your CISWI unit's impacts that are prepared to comply with State, local, or other... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What is a siting analysis? 60.2050 Section 60.2050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

40 CFR 60.2050 - What is a siting analysis?

Code of Federal Regulations, 2011 CFR

2011-07-01

... alternatives. (b) Analyses of your CISWI unit's impacts that are prepared to comply with State, local, or other... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What is a siting analysis? 60.2050 Section 60.2050 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

Protein pharmacophore selection using hydration-site analysis

PubMed Central

Hu, Bingjie; Lill, Markus A.

2012-01-01

Virtual screening using pharmacophore models is an efficient method to identify potential lead compounds for target proteins. Pharmacophore models based on protein structures are advantageous because a priori knowledge of active ligands is not required and the models are not biased by the chemical space of previously identified actives. However, in order to capture most potential interactions between all potentially binding ligands and the protein, the size of the pharmacophore model, i.e. number of pharmacophore elements, is typically quite large and therefore reduces the efficiency of pharmacophore based screening. We have developed a new method to select important pharmacophore elements using hydration-site information. The basic premise is that ligand functional groups that replace water molecules in the apo protein contribute strongly to the overall binding affinity of the ligand, due to the additional free energy gained from releasing the water molecule into the bulk solvent. We computed the free energy of water released from the binding site for each hydration site using thermodynamic analysis of molecular dynamics (MD) simulations. Pharmacophores which are co-localized with hydration sites with estimated favorable contributions to the free energy of binding are selected to generate a reduced pharmacophore model. We constructed reduced pharmacophore models for three protein systems and demonstrated good enrichment quality combined with high efficiency. The reduction in pharmacophore model size reduces the required screening time by a factor of 200–500 compared to using all protein pharmacophore elements. We also describe a training process using a small set of known actives to reliably select the optimal set of criteria for pharmacophore selection for each protein system. PMID:22397751

Anatomic Site Based Ploidy Analysis of Oral Premalignant Lesions

PubMed Central

Islam, M. N.; Kornberg, L.; Veenker, E.; Cohen, D. M.

2009-01-01

The location of oral leukoplakia correlates strongly with the probability of finding dysplastic or malignant alterations at biopsy. It is well established that early detection can dramatically improve the 5-year survival rates for oral squamous cell carcinomas. Since aneuploidy is predictive of future conversion to malignancy, we hypothesized that dysplastic lesions from high-risk sites (floor of mouth, tongue and lips) would exhibit greater aneuploidy than low-risk sites (palate, gingiva and buccal mucosa). Epithelial sections from 60 archival samples diagnosed as mild dysplasia (36 females, 20 males) from various high/low risk locations were stained with Blue Feulgen Stain for DNA Ploidy Analysis (Clarient, Aliso Viejo, CA) and ploidy was analyzed using a ChromaVision ACIS II (Clarient, ALiso Viejo, CA) Image cytometry system. A DNA histogram was generated using an image analyzing software that evaluated the amount of Feulgen stain which is proportional to the amount of nuclear DNA. An ANOVA analysis followed by the Student’s‘t’ test revealed significant differences between means (P ≤ 0.05). Lesions originating from lateral/ventral tongue (85%), floor of mouth (50%) and soft palate (44%) exhibited a higher frequency of aneuploidy than lesions from gingiva (22%) and lower lip (25%). This pilot study demonstrates that dysplastic lesions from high-risk sites such as the floor of the mouth and lateral/ventral tongue have higher frequency of aneuploidy. PMID:20237983

40 CFR 60.2895 - What is a siting analysis?

Code of Federal Regulations, 2010 CFR

2010-07-01

... health or the environment. In considering such alternatives, you may consider costs, energy impacts...) Analyses of your OSWI unit's impacts that are prepared to comply with State, local, or other Federal... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What is a siting analysis? 60.2895...

40 CFR 60.2895 - What is a siting analysis?

Code of Federal Regulations, 2011 CFR

2011-07-01

... health or the environment. In considering such alternatives, you may consider costs, energy impacts...) Analyses of your OSWI unit's impacts that are prepared to comply with State, local, or other Federal... 40 Protection of Environment 6 2011-07-01 2011-07-01 false What is a siting analysis? 60.2895...

Evaluation of site effects on ground motions based on equivalent linear site response analysis and liquefaction potential in Chennai, south India

NASA Astrophysics Data System (ADS)

Nampally, Subhadra; Padhy, Simanchal; Trupti, S.; Prabhakar Prasad, P.; Seshunarayana, T.

2018-05-01

We study local site effects with detailed geotechnical and geophysical site characterization to evaluate the site-specific seismic hazard for the seismic microzonation of the Chennai city in South India. A Maximum Credible Earthquake (MCE) of magnitude 6.0 is considered based on the available seismotectonic and geological information of the study area. We synthesized strong ground motion records for this target event using stochastic finite-fault technique, based on a dynamic corner frequency approach, at different sites in the city, with the model parameters for the source, site, and path (attenuation) most appropriately selected for this region. We tested the influence of several model parameters on the characteristics of ground motion through simulations and found that stress drop largely influences both the amplitude and frequency of ground motion. To minimize its influence, we estimated stress drop after finite bandwidth correction, as expected from an M6 earthquake in Indian peninsula shield for accurately predicting the level of ground motion. Estimates of shear wave velocity averaged over the top 30 m of soil (V S30) are obtained from multichannel analysis of surface wave (MASW) at 210 sites at depths of 30 to 60 m below the ground surface. Using these V S30 values, along with the available geotechnical information and synthetic ground motion database obtained, equivalent linear one-dimensional site response analysis that approximates the nonlinear soil behavior within the linear analysis framework was performed using the computer program SHAKE2000. Fundamental natural frequency, Peak Ground Acceleration (PGA) at surface and rock levels, response spectrum at surface level for different damping coefficients, and amplification factors are presented at different sites of the city. Liquefaction study was done based on the V S30 and PGA values obtained. The major findings suggest show that the northeast part of the city is characterized by (i) low V S30 values

A compact, all-optical, THz wave generator based on self-modulation in a slab photonic crystal waveguide with a single sub-nanometer graphene layer.

PubMed

Asadi, R; Ouyang, Z; Mohammd, M M

2015-07-14

We design a compact, all-optical THz wave generator based on self-modulation in a 1-D slab photonic crystal (PhC) waveguide with a single sub-nanometer graphene layer by using enhanced nonlinearity of graphene. It has been shown that at the bandgap edge of higher bands of a 1-D slab PhC, through only one sub-nanometer graphene layer we can obtain a compact, high modulation factor (about 0.98 percent), self-intensity modulator at a high frequency (about 0.6 THz) and low threshold intensity (about 15 MW per square centimeter), and further a compact, all-optical THz wave generator by integrating the self-modulator with a THz photodiode or photonic mixer. Such a THz source is expected to have a relatively high efficiency compared with conventional sources based on optical methods. The proposed THz source can find wide applications in THz science and technology, e.g., in THz imaging, THz sensors and detectors, THz communication systems, and THz optical integrated logic circuits.

Rainfall frequency analysis for ungauged sites using satellite precipitation products

NASA Astrophysics Data System (ADS)

Gado, Tamer A.; Hsu, Kuolin; Sorooshian, Soroosh

2017-11-01

The occurrence of extreme rainfall events and their impacts on hydrologic systems and society are critical considerations in the design and management of a large number of water resources projects. As precipitation records are often limited or unavailable at many sites, it is essential to develop better methods for regional estimation of extreme rainfall at these partially-gauged or ungauged sites. In this study, an innovative method for regional rainfall frequency analysis for ungauged sites is presented. The new method (hereafter, this is called the RRFA-S) is based on corrected annual maximum series obtained from a satellite precipitation product (e.g., PERSIANN-CDR). The probability matching method (PMM) is used here for bias correction to match the CDF of satellite-based precipitation data with the gauged data. The RRFA-S method was assessed through a comparative study with the traditional index flood method using the available annual maximum series of daily rainfall in two different regions in USA (11 sites in Colorado and 18 sites in California). The leave-one-out cross-validation technique was used to represent the ungauged site condition. Results of this numerical application have found that the quantile estimates obtained from the new approach are more accurate and more robust than those given by the traditional index flood method.

Improving Sampling, Analysis, and Data Management for Site Investigation and Cleanup

EPA Pesticide Factsheets

The United States Environmental Protection Agency (EPA) supports the adoption of streamlined approaches to sampling, analysis, and data management activities conducted during site assessment, characterization, and cleanup.

Aberration-Corrected Electron Beam Lithography at the One Nanometer Length Scale

DOE PAGES

Manfrinato, Vitor R.; Stein, Aaron; Zhang, Lihua; ...

2017-04-18

Patterning materials efficiently at the smallest length scales has been a longstanding challenge in nanotechnology. Electron-beam lithography (EBL) is the primary method for patterning arbitrary features, but EBL has not reliably provided sub-4 nm patterns. The few competing techniques that have achieved this resolution are orders of magnitude slower than EBL. In this work, we employed an aberration-corrected scanning transmission electron microscope for lithography to achieve unprecedented resolution. Here we show aberration-corrected EBL at the one nanometer length scale using poly(methyl methacrylate) (PMMA) and have produced both the smallest isolated feature in any conventional resist (1.7 ± 0.5 nm) andmore » the highest density patterns in PMMA (10.7 nm pitch for negative-tone and 17.5 nm pitch for positive-tone PMMA). We also demonstrate pattern transfer from the resist to semiconductor and metallic materials at the sub-5 nm scale. These results indicate that polymer-based nanofabrication can achieve feature sizes comparable to the Kuhn length of PMMA and ten times smaller than its radius of gyration. Use of aberration-corrected EBL will increase the resolution, speed, and complexity in nanomaterial fabrication.« less

Recent Design Development in Molecular Imaging for Breast Cancer Detection Using Nanometer CMOS Based Sensors.

PubMed

Nguyen, Dung C; Ma, Dongsheng Brian; Roveda, Janet M W

2012-01-01

As one of the key clinical imaging methods, the computed X-ray tomography can be further improved using new nanometer CMOS sensors. This will enhance the current technique's ability in terms of cancer detection size, position, and detection accuracy on the anatomical structures. The current paper reviewed designs of SOI-based CMOS sensors and their architectural design in mammography systems. Based on the existing experimental results, using the SOI technology can provide a low-noise (SNR around 87.8 db) and high-gain (30 v/v) CMOS imager. It is also expected that, together with the fast data acquisition designs, the new type of imagers may play important roles in the near-future high-dimensional images in additional to today's 2D imagers.

On-Site Renewable Energy and Green Buildings: A System-Level Analysis.

PubMed

Al-Ghamdi, Sami G; Bilec, Melissa M

2016-05-03

Adopting a green building rating system (GBRSs) that strongly considers use of renewable energy can have important environmental consequences, particularly in developing countries. In this paper, we studied on-site renewable energy and GBRSs at the system level to explore potential benefits and challenges. While we have focused on GBRSs, the findings can offer additional insight for renewable incentives across sectors. An energy model was built for 25 sites to compute the potential solar and wind power production on-site and available within the building footprint and regional climate. A life-cycle approach and cost analysis were then completed to analyze the environmental and economic impacts. Environmental impacts of renewable energy varied dramatically between sites, in some cases, the environmental benefits were limited despite the significant economic burden of those renewable systems on-site and vice versa. Our recommendation for GBRSs, and broader policies and regulations, is to require buildings with higher environmental impacts to achieve higher levels of energy performance and on-site renewable energy utilization, instead of fixed percentages.

A web server for analysis, comparison and prediction of protein ligand binding sites.

PubMed

Singh, Harinder; Srivastava, Hemant Kumar; Raghava, Gajendra P S

2016-03-25

One of the major challenges in the field of system biology is to understand the interaction between a wide range of proteins and ligands. In the past, methods have been developed for predicting binding sites in a protein for a limited number of ligands. In order to address this problem, we developed a web server named 'LPIcom' to facilitate users in understanding protein-ligand interaction. Analysis, comparison and prediction modules are available in the "LPIcom' server to predict protein-ligand interacting residues for 824 ligands. Each ligand must have at least 30 protein binding sites in PDB. Analysis module of the server can identify residues preferred in interaction and binding motif for a given ligand; for example residues glycine, lysine and arginine are preferred in ATP binding sites. Comparison module of the server allows comparing protein-binding sites of multiple ligands to understand the similarity between ligands based on their binding site. This module indicates that ATP, ADP and GTP ligands are in the same cluster and thus their binding sites or interacting residues exhibit a high level of similarity. Propensity-based prediction module has been developed for predicting ligand-interacting residues in a protein for more than 800 ligands. In addition, a number of web-based tools have been integrated to facilitate users in creating web logo and two-sample between ligand interacting and non-interacting residues. In summary, this manuscript presents a web-server for analysis of ligand interacting residue. This server is available for public use from URL http://crdd.osdd.net/raghava/lpicom .

Positive feedback can lead to dynamic nanometer-scale clustering on cell membranes

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

Wehrens, Martijn; Rein ten Wolde, Pieter; Mugler, Andrew, E-mail: amugler@purdue.edu

2014-11-28

Clustering of molecules on biological membranes is a widely observed phenomenon. A key example is the clustering of the oncoprotein Ras, which is known to be important for signal transduction in mammalian cells. Yet, the mechanism by which Ras clusters form and are maintained remains unclear. Recently, it has been discovered that activated Ras promotes further Ras activation. Here we show using particle-based simulation that this positive feedback is sufficient to produce persistent clusters of active Ras molecules at the nanometer scale via a dynamic nucleation mechanism. Furthermore, we find that our cluster statistics are consistent with experimental observations ofmore » the Ras system. Interestingly, we show that our model does not support a Turing regime of macroscopic reaction-diffusion patterning, and therefore that the clustering we observe is a purely stochastic effect, arising from the coupling of positive feedback with the discrete nature of individual molecules. These results underscore the importance of stochastic and dynamic properties of reaction diffusion systems for biological behavior.« less

Analysis of Factors Influencing Hydration Site Prediction Based on Molecular Dynamics Simulations

PubMed Central

2015-01-01

Water contributes significantly to the binding of small molecules to proteins in biochemical systems. Molecular dynamics (MD) simulation based programs such as WaterMap and WATsite have been used to probe the locations and thermodynamic properties of hydration sites at the surface or in the binding site of proteins generating important information for structure-based drug design. However, questions associated with the influence of the simulation protocol on hydration site analysis remain. In this study, we use WATsite to investigate the influence of factors such as simulation length and variations in initial protein conformations on hydration site prediction. We find that 4 ns MD simulation is appropriate to obtain a reliable prediction of the locations and thermodynamic properties of hydration sites. In addition, hydration site prediction can be largely affected by the initial protein conformations used for MD simulations. Here, we provide a first quantification of this effect and further indicate that similar conformations of binding site residues (RMSD < 0.5 Å) are required to obtain consistent hydration site predictions. PMID:25252619

Analysis of factors influencing hydration site prediction based on molecular dynamics simulations.

PubMed

Yang, Ying; Hu, Bingjie; Lill, Markus A

2014-10-27

Water contributes significantly to the binding of small molecules to proteins in biochemical systems. Molecular dynamics (MD) simulation based programs such as WaterMap and WATsite have been used to probe the locations and thermodynamic properties of hydration sites at the surface or in the binding site of proteins generating important information for structure-based drug design. However, questions associated with the influence of the simulation protocol on hydration site analysis remain. In this study, we use WATsite to investigate the influence of factors such as simulation length and variations in initial protein conformations on hydration site prediction. We find that 4 ns MD simulation is appropriate to obtain a reliable prediction of the locations and thermodynamic properties of hydration sites. In addition, hydration site prediction can be largely affected by the initial protein conformations used for MD simulations. Here, we provide a first quantification of this effect and further indicate that similar conformations of binding site residues (RMSD < 0.5 Å) are required to obtain consistent hydration site predictions.

Analysis of governmental Web sites on food safety issues: a global perspective.

PubMed

Namkung, Young; Almanza, Barbara A

2006-10-01

Despite a growing concern over food safety issues, as well as a growing dependence on the Internet as a source of information, little research has been done to examine the presence and relevance of food safety-related information on Web sites. The study reported here conducted Web site analysis in order to examine the current operational status of governmental Web sites on food safety issues. The study also evaluated Web site usability, especially information dimensionalities such as utility, currency, and relevance of content, from the perspective of the English-speaking consumer. Results showed that out of 192 World Health Organization members, 111 countries operated governmental Web sites that provide information about food safety issues. Among 171 searchable Web sites from the 111 countries, 123 Web sites (71.9 percent) were accessible, and 81 of those 123 (65.9 percent) were available in English. The majority of Web sites offered search engine tools and related links for more information, but their availability and utility was limited. In terms of content, 69.9 percent of Web sites offered information on foodborne-disease outbreaks, compared with 31.5 percent that had travel- and health-related information.

Desert Test Site Uniformity Analysis

NASA Technical Reports Server (NTRS)

Kerola, Dana X.; Bruegge, Carol J.

2009-01-01

Desert test sites such as Railroad Valley (RRV) Nevada, Egypt-1, and Libya-4 are commonly targeted to assess the on-orbit radiometric performance of sensors. Railroad Valley is used for vicarious calibration experiments, where a field-team makes ground measurements to produce accurate estimates of top-of-atmosphere (TOA) radiances. The Sahara desert test sites are not instrumented, but provide a stable target that can be used for sensor cross-comparisons, or for stability monitoring of a single sensor. These sites are of interest to NASA's Atmospheric Carbon Observation from Space (ACOS) and JAXA's Greenhouse Gas Observation SATellite (GOSAT) programs. This study assesses the utility of these three test sites to the ACOS and GOSAT calibration teams. To simulate errors in sensor-measured radiance with pointing errors, simulated data have been created using MODIS Aqua data. MODIS data are further utilized to validate the campaign data acquired from June 22 through July 5, 2009. The first GOSAT vicarious calibration experiment was conducted during this timeframe.

Nondestructive characterization of textured a-Si:H/c-Si heterojunction solar cell structures with nanometer-scale a-Si:H and In2O3:Sn layers by spectroscopic ellipsometry

NASA Astrophysics Data System (ADS)

Matsuki, Nobuyuki; Fujiwara, Hiroyuki

2013-07-01

Nanometer-scale hydrogenated amorphous silicon (a-Si:H) layers formed on crystalline silicon (c-Si) with pyramid-shaped textures have been characterized by spectroscopic ellipsometry (SE) using a tilt angle measurement configuration, in an attempt to establish a nondestructive method for the structural characterization of the a-Si:H/c-Si heterojunction solar cells. By applying an a-Si:H dielectric function model developed recently, the thickness and SiH2 content of the a-Si:H layer have been determined even on the textured substrates. Furthermore, from the SE analysis incorporating the Drude model, the carrier properties of the In2O3:Sn layers in the textured solar-cell structure have been characterized.

Uncertainty Analysis Framework - Hanford Site-Wide Groundwater Flow and Transport Model

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

Cole, Charles R.; Bergeron, Marcel P.; Murray, Christopher J.

2001-11-09

Pacific Northwest National Laboratory (PNNL) embarked on a new initiative to strengthen the technical defensibility of the predictions being made with a site-wide groundwater flow and transport model at the U.S. Department of Energy Hanford Site in southeastern Washington State. In FY 2000, the focus of the initiative was on the characterization of major uncertainties in the current conceptual model that would affect model predictions. The long-term goals of the initiative are the development and implementation of an uncertainty estimation methodology in future assessments and analyses using the site-wide model. This report focuses on the development and implementation of anmore » uncertainty analysis framework.« less

40 CFR 60.1150 - How do I submit my siting analysis?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Waste Combustion Units for Which Construction is Commenced After August 30, 1999 or for Which... items as part of the notice of construction: (a) Your siting analysis. (b) Your notice of the public...

Selective Enrichment and Direct Analysis of Protein S-Palmitoylation Sites.

PubMed

Thinon, Emmanuelle; Fernandez, Joseph P; Molina, Henrik; Hang, Howard C

2018-05-04

S-Fatty-acylation is the covalent attachment of long chain fatty acids, predominately palmitate (C16:0, S-palmitoylation), to cysteine (Cys) residues via a thioester linkage on proteins. This post-translational and reversible lipid modification regulates protein function and localization in eukaryotes and is important in mammalian physiology and human diseases. While chemical labeling methods have improved the detection and enrichment of S-fatty-acylated proteins, mapping sites of modification and characterizing the endogenously attached fatty acids are still challenging. Here, we describe the integration and optimization of fatty acid chemical reporter labeling with hydroxylamine-mediated enrichment of S-fatty-acylated proteins and direct tagging of modified Cys residues to selectively map lipid modification sites. This afforded improved enrichment and direct identification of many protein S-fatty-acylation sites compared to previously described methods. Notably, we directly identified the S-fatty-acylation sites of IFITM3, an important interferon-stimulated inhibitor of virus entry, and we further demonstrated that the highly conserved Cys residues are primarily modified by palmitic acid. The methods described here should facilitate the direct analysis of protein S-fatty-acylation sites and their endogenously attached fatty acids in diverse cell types and activation states important for mammalian physiology and diseases.

Large-scale freestanding nanometer-thick graphite pellicles for mass production of nanodevices beyond 10 nm.

PubMed

Kim, Seul-Gi; Shin, Dong-Wook; Kim, Taesung; Kim, Sooyoung; Lee, Jung Hun; Lee, Chang Gu; Yang, Cheol-Woong; Lee, Sungjoo; Cho, Sang Jin; Jeon, Hwan Chul; Kim, Mun Ja; Kim, Byung-Gook; Yoo, Ji-Beom

2015-09-21

Extreme ultraviolet lithography (EUVL) has received much attention in the semiconductor industry as a promising candidate to extend dimensional scaling beyond 10 nm. We present a new pellicle material, nanometer-thick graphite film (NGF), which shows an extreme ultraviolet (EUV) transmission of 92% at a thickness of 18 nm. The maximum temperature induced by laser irradiation (λ = 800 nm) of 9.9 W cm(-2) was 267 °C, due to the high thermal conductivity of the NGF. The freestanding NGF was found to be chemically stable during annealing at 500 °C in a hydrogen environment. A 50 × 50 mm large area freestanding NGF was fabricated using the wet and dry transfer (WaDT) method. The NGF can be used as an EUVL pellicle for the mass production of nanodevices beyond 10 nm.

Antimicrobial Susceptibility Test with Plasmonic Imaging and Tracking of Single Bacterial Motions on Nanometer Scale.

PubMed

Syal, Karan; Iriya, Rafael; Yang, Yunze; Yu, Hui; Wang, Shaopeng; Haydel, Shelley E; Chen, Hong-Yuan; Tao, Nongjian

2016-01-26

Antimicrobial susceptibility tests (ASTs) are important for confirming susceptibility to empirical antibiotics and detecting resistance in bacterial isolates. Currently, most ASTs performed in clinical microbiology laboratories are based on bacterial culturing, which take days to complete for slowly growing microorganisms. A faster AST will reduce morbidity and mortality rates and help healthcare providers administer narrow spectrum antibiotics at the earliest possible treatment stage. We report the development of a nonculture-based AST using a plasmonic imaging and tracking (PIT) technology. We track the motion of individual bacterial cells tethered to a surface with nanometer (nm) precision and correlate the phenotypic motion with bacterial metabolism and antibiotic action. We show that antibiotic action significantly slows down bacterial motion, which can be quantified for development of a rapid phenotypic-based AST.

A method for the automated detection phishing websites through both site characteristics and image analysis

NASA Astrophysics Data System (ADS)

White, Joshua S.; Matthews, Jeanna N.; Stacy, John L.

2012-06-01

Phishing website analysis is largely still a time-consuming manual process of discovering potential phishing sites, verifying if suspicious sites truly are malicious spoofs and if so, distributing their URLs to the appropriate blacklisting services. Attackers increasingly use sophisticated systems for bringing phishing sites up and down rapidly at new locations, making automated response essential. In this paper, we present a method for rapid, automated detection and analysis of phishing websites. Our method relies on near real-time gathering and analysis of URLs posted on social media sites. We fetch the pages pointed to by each URL and characterize each page with a set of easily computed values such as number of images and links. We also capture a screen-shot of the rendered page image, compute a hash of the image and use the Hamming distance between these image hashes as a form of visual comparison. We provide initial results demonstrate the feasibility of our techniques by comparing legitimate sites to known fraudulent versions from Phishtank.com, by actively introducing a series of minor changes to a phishing toolkit captured in a local honeypot and by performing some initial analysis on a set of over 2.8 million URLs posted to Twitter over a 4 days in August 2011. We discuss the issues encountered during our testing such as resolvability and legitimacy of URL's posted on Twitter, the data sets used, the characteristics of the phishing sites we discovered, and our plans for future work.

OLEM Center for Program Analysis Site Analysis Data

EPA Pesticide Factsheets

This asset includes environmental justice-related analyses of population located within a mile of Superfund and RCRA Corrective Action sites. It characterizes demographics and socio-economic characteristics of near-site communities as compared to the average U.S. population. It also examined children of up to 17 years of age living within 1 mile of SF and RCRA CA sites where human health protective measures may not have been in place. It compared data on the health status of these children to the status of all children in the U.S. Information from this study contributed to the America's Children and the Environment (ACE) report for 2013.

Bimetallic Ag-Pt Sub-nanometer Supported Clusters as Highly Efficient and Robust Oxidation Catalysts

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

Negreiros, Fabio R.; Halder, Avik; Yin, Chunrong

A combined experimental and theoretical investigation of Ag-Pt sub-nanometer clusters as heterogeneous catalysts in the CO -> CO2 reaction (COox) is presented. Ag9Pt2 and Ag9Pt3 clusters are size-selected in the gas phase, deposited on an ultrathin amorphous alumina support, and tested as catalysts experimentally under realistic conditions and by first-principles simulations at realistic coverage. Insitu GISAXS/TPRx demonstrates that the clusters do not sinter or deactivate even after prolonged exposure to reactants at high temperature, and present comparable, extremely high COox catalytic efficiency. Such high activity and stability are ascribed to a synergic role of Ag and Pt in ultranano-aggregates, inmore » which Pt anchors the clusters to the support and binds and activates two CO molecules, while Ag binds and activates O-2, and Ag/Pt surface proximity disfavors poisoning by CO or oxidized species.« less

Helium Ion Microscopy (HIM) for the imaging of biological samples at sub-nanometer resolution

NASA Astrophysics Data System (ADS)

Joens, Matthew S.; Huynh, Chuong; Kasuboski, James M.; Ferranti, David; Sigal, Yury J.; Zeitvogel, Fabian; Obst, Martin; Burkhardt, Claus J.; Curran, Kevin P.; Chalasani, Sreekanth H.; Stern, Lewis A.; Goetze, Bernhard; Fitzpatrick, James A. J.

2013-12-01

Scanning Electron Microscopy (SEM) has long been the standard in imaging the sub-micrometer surface ultrastructure of both hard and soft materials. In the case of biological samples, it has provided great insights into their physical architecture. However, three of the fundamental challenges in the SEM imaging of soft materials are that of limited imaging resolution at high magnification, charging caused by the insulating properties of most biological samples and the loss of subtle surface features by heavy metal coating. These challenges have recently been overcome with the development of the Helium Ion Microscope (HIM), which boasts advances in charge reduction, minimized sample damage, high surface contrast without the need for metal coating, increased depth of field, and 5 angstrom imaging resolution. We demonstrate the advantages of HIM for imaging biological surfaces as well as compare and contrast the effects of sample preparation techniques and their consequences on sub-nanometer ultrastructure.

Helium Ion Microscopy (HIM) for the imaging of biological samples at sub-nanometer resolution.

PubMed

Joens, Matthew S; Huynh, Chuong; Kasuboski, James M; Ferranti, David; Sigal, Yury J; Zeitvogel, Fabian; Obst, Martin; Burkhardt, Claus J; Curran, Kevin P; Chalasani, Sreekanth H; Stern, Lewis A; Goetze, Bernhard; Fitzpatrick, James A J

2013-12-17

Scanning Electron Microscopy (SEM) has long been the standard in imaging the sub-micrometer surface ultrastructure of both hard and soft materials. In the case of biological samples, it has provided great insights into their physical architecture. However, three of the fundamental challenges in the SEM imaging of soft materials are that of limited imaging resolution at high magnification, charging caused by the insulating properties of most biological samples and the loss of subtle surface features by heavy metal coating. These challenges have recently been overcome with the development of the Helium Ion Microscope (HIM), which boasts advances in charge reduction, minimized sample damage, high surface contrast without the need for metal coating, increased depth of field, and 5 angstrom imaging resolution. We demonstrate the advantages of HIM for imaging biological surfaces as well as compare and contrast the effects of sample preparation techniques and their consequences on sub-nanometer ultrastructure.

Analysis of Elementary School Web Sites

ERIC Educational Resources Information Center

Hartshorne, Richard; Friedman, Adam; Algozzine, Bob; Kaur, Daljit

2008-01-01

While researchers have studied the use and value of educational software for many years, study of school Web sites and/or their effectiveness is limited. In this investigation, we identified goals and functions of school Web sites and used the foundations of effective Web site design to develop an evaluation checklist. We then applied these…

Summary and Comparison of Multiphase Streambed Scour Analysis at Selected Bridge Sites in Alaska

USGS Publications Warehouse

Conaway, Jeffrey S.

2004-01-01

The U.S. Geological Survey and the Alaska Department of Transportation and Public Facilities undertook a cooperative multiphase study of streambed scour at selected bridges in Alaska beginning in 1994. Of the 325 bridges analyzed for susceptibility to scour in the preliminary phase, 54 bridges were selected for a more intensive analysis that included site investigations. Cross-section geometry and hydraulic properties for each site in this study were determined from field surveys and bridge plans. Water-surface profiles were calculated for the 100- and 500-year floods using the Hydrologic Engineering Center?s River Analysis System and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths for the 100- and 500-year recurrence-interval discharges exceeded 5 feet at six bridges, and pier-scour depths exceeded 10 feet at 24 bridges. Complex pier-scour computations were made at 10 locations where the computed contraction-scour depths would expose pier footings. Pressure scour was evaluated at three bridges where the modeled flood water-surface elevations intersected the bridge structure. Site investigation at the 54 scour-critical bridges was used to evaluate the effectiveness of the preliminary scour analysis. Values for channel-flow angle of attack and approach-channel width were estimated from bridge survey plans for the preliminary study and were measured during a site investigation for this study. These two variables account for changes in scour depths between the preliminary analysis and subsequent reanalysis for most sites. Site investigation is needed for best estimates of scour at bridges with survey plans that indicate a channel-flow angle of attack and for locations where survey plans did not include sufficient channel geometry upstream of the bridge.

Construction of nanometer cisplatin core-ferritin (NCC-F) and proteomic analysis of gastric cancer cell apoptosis induced with cisplatin released from the NCC-F.

PubMed

Ji, Xue-Tao; Huang, Lin; Huang, He-Qing

2012-06-18

Both transmission electron microscopy (TEM) and fluorescence spectrometry were used to reveal the characteristics of both subunit disassociation and recombination in apo-pig pancreas ferritin (apoPPF) in an alkaline medium ranging reversibly from pH 7.0 to 13.0. The experimental results indicated that apoPPF could be completely disassociated into 24 free subunits at pH 13.0, and then these subunits could be quickly reassembled into the original apoPPF once the pH of the reactive medium was returned to pH7.0. This novel and simple method could be used to effectively construct a novel nanometer cisplatin core-PPF (NCC-PPF). The major characteristics of NCC-PPF were investigated using various analytical methods such as ultraviolet-spectrometry, circular dichroism spectrometry and TEM, which indicated that its molecular structure was still similar to that of the original apoPPF. Results from the inductively coupled plasma mass spectrometer (ICP-MS) method showed that 11.26 cisplatin (CDDP) molecules were successfully packaged within the NCC-PPF shell, indicating that each molecule of apoPPF had the ability to enwrap 11.26 CDDP molecules for constructing the NCC-PPF. Flow cytometry showed that NCC-PPF also had the ability to release CDDP for inducing the apoptosis of gastric cancer cells BGC823 (GCC), but this phenomenon could scarcely be observed using apoPPF. A differential proteomic technique using two-dimensional electrophoresis (2-DE) gels selected and identified the differential proteins from cell apoptosis in order to reveal the molecular pathway of GCC apoptosis by both NCC-PPF and free CDDP, giving 13 differential expression proteins. These differential proteins could be further classified into six groups, which were described as being involved in the regulation of apoptosis, RNA transcription, oxidative stress response, signal transduction, cell metabolism, and cytoskeleton changes. In addition, a real-time PCR method was used to prove the expression level of

Prognostic value of site-specific extra-hepatic disease in hepatocellular carcinoma: a SEER database analysis.

PubMed

Oweira, Hani; Petrausch, Ulf; Helbling, Daniel; Schmidt, Jan; Mehrabi, Arianeb; Schöb, Othmar; Giryes, Anwar; Abdel-Rahman, Omar

2017-07-01

We the prognostic value of site-specific extra-hepatic disease in hepatocellular carcinoma (HCC) patients registered within the surveillance, epidemiology and end results (SEER) database. SEER database (2010-2013) has been queried through SEER*Stat program to determine the prognosis of advanced HCC patients according to the site of extra-hepatic disease. Survival analysis has been conducted through Kaplan Meier analysis. A total of 4396 patients with stage IV HCC were identified in the period from 2010-2013 and they were included into this analysis. Patients with isolated regional lymph node involvement have better outcomes compared to patients with any other site of extra-hepatic disease (P < 0.0001 for both endpoints). Among patients with distant metastases, patients with bone metastases have better outcomes compared to patients with lung metastases (P < 0.0001 for both endpoints). Multivariate analysis revealed that younger age, normal alpha fetoprotein, single site of extra-hepatic disease, local treatment to the primary tumor and surgery to the metastatic disease were associated with better overall survival and liver cancer-specific survival. Within the limits of the current SEER analysis, HCC patients with isolated lung metastases seem to have worse outcomes compared to patients with isolated bone or regional nodal metastases.​.

SAMPLING AND ANALYSIS OF MONITORING WELLS AT EPA RESEARCH SITES

EPA Science Inventory

I have been asked to speak to the Environmental Science class at ECU on 04-26-04 on the subject of sample collection and analysis of monitoring wells at EPA research sites that I have been involved with. I plan on demonstrating the techniques of well water collection and meter a...

2002 Hyperspectral Analysis of Hazardous Waste Sites on the Savannah River Site

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

Gladden, J.B.

2003-08-28

Hazardous waste site inspection is a labor intensive, time consuming job, performed primarily on the ground using visual inspection and instrumentation. It is an expensive process to continually monitor hazardous waste and/or landfill sites to determine if they are maintaining their integrity. In certain instances, it may be possible to monitor aspects of the hazardous waste sites and landfills remotely. The utilization of multispectral data was suggested for the mapping of clays and iron oxides associated with contaminated groundwater, vegetation stress, and methane gas emissions (which require longer wavelength detectors). The Savannah River Site (SRS) near Aiken, S.C. is amore » United States Department of Energy facility operated by the Westinghouse Savannah River Company. For decades the SRS was responsible for developing weapons grade plutonium and other materials for the nation's nuclear defense. Hazardous waste was generated during this process. Waste storage site inspection is a particularly important issue at the SRS because there are over 100 hazardous waste sites scattered throughout the 300 mile complex making it difficult to continually monitor all of the facilities. The goal is to use remote sensing technology to identify surface anomalies on the hazardous waste sites as early as possible so that remedial work can take place rapidly to maintain the integrity of the storage sites. The anomalous areas are then targeted for intensive in situ human examination and measurement. During the 1990s, many of the hazardous waste sites were capped with protective layers of polyethelene sheeting and soil, and planted with bahia grass and/or centipede grass. This research investigated hyperspectral remote sensing technology to determine if it can be used to measure accurately and monitor possible indicators of change on vegetated hazardous waste sites. Specifically, it evaluated the usefulness of hyperspectral remote sensing to assess the condition of vegetation

Examination of a Social-Networking Site Activities Scale (SNSAS) Using Rasch Analysis

ERIC Educational Resources Information Center

Alhaythami, Hassan; Karpinski, Aryn; Kirschner, Paul; Bolden, Edward

2017-01-01

This study examined the psychometric properties of a social-networking site (SNS) activities scale (SNSAS) using Rasch Analysis. Items were also examined with Rasch Principal Components Analysis (PCA) and Differential Item Functioning (DIF) across groups of university students (i.e., males and females from the United States [US] and Europe; N =…

Probing dynamics and pinning of single vortices in superconductors at nanometer scales.

PubMed

Embon, L; Anahory, Y; Suhov, A; Halbertal, D; Cuppens, J; Yakovenko, A; Uri, A; Myasoedov, Y; Rappaport, M L; Huber, M E; Gurevich, A; Zeldov, E

2015-01-07

The dynamics of quantized magnetic vortices and their pinning by materials defects determine electromagnetic properties of superconductors, particularly their ability to carry non-dissipative currents. Despite recent advances in the understanding of the complex physics of vortex matter, the behavior of vortices driven by current through a multi-scale potential of the actual materials defects is still not well understood, mostly due to the scarcity of appropriate experimental tools capable of tracing vortex trajectories on nanometer scales. Using a novel scanning superconducting quantum interference microscope we report here an investigation of controlled dynamics of vortices in lead films with sub-Angstrom spatial resolution and unprecedented sensitivity. We measured, for the first time, the fundamental dependence of the elementary pinning force of multiple defects on the vortex displacement, revealing a far more complex behavior than has previously been recognized, including striking spring softening and broken-spring depinning, as well as spontaneous hysteretic switching between cellular vortex trajectories. Our results indicate the importance of thermal fluctuations even at 4.2 K and of the vital role of ripples in the pinning potential, giving new insights into the mechanisms of magnetic relaxation and electromagnetic response of superconductors.

Probing dynamics and pinning of single vortices in superconductors at nanometer scales

NASA Astrophysics Data System (ADS)

Embon, L.; Anahory, Y.; Suhov, A.; Halbertal, D.; Cuppens, J.; Yakovenko, A.; Uri, A.; Myasoedov, Y.; Rappaport, M. L.; Huber, M. E.; Gurevich, A.; Zeldov, E.

2015-01-01

The dynamics of quantized magnetic vortices and their pinning by materials defects determine electromagnetic properties of superconductors, particularly their ability to carry non-dissipative currents. Despite recent advances in the understanding of the complex physics of vortex matter, the behavior of vortices driven by current through a multi-scale potential of the actual materials defects is still not well understood, mostly due to the scarcity of appropriate experimental tools capable of tracing vortex trajectories on nanometer scales. Using a novel scanning superconducting quantum interference microscope we report here an investigation of controlled dynamics of vortices in lead films with sub-Angstrom spatial resolution and unprecedented sensitivity. We measured, for the first time, the fundamental dependence of the elementary pinning force of multiple defects on the vortex displacement, revealing a far more complex behavior than has previously been recognized, including striking spring softening and broken-spring depinning, as well as spontaneous hysteretic switching between cellular vortex trajectories. Our results indicate the importance of thermal fluctuations even at 4.2 K and of the vital role of ripples in the pinning potential, giving new insights into the mechanisms of magnetic relaxation and electromagnetic response of superconductors.

The Earliest Chinese Proto-Porcelain Excavated from Kiln Sites: An Elemental Analysis

PubMed Central

Li, Yu; Zhang, Bin; Cheng, Huansheng; Zheng, Jianming

2015-01-01

In June 2012, the Piaoshan kiln site was excavated in Huzhou, Zhejiang Province, which hitherto proved to be the earliest known Chinese proto-porcelain kiln. Judging from the decorative patterns of unearthed impressed stoneware and proto-porcelain sherds, the site was determined to date to the late Xia (c. 2070–c. 1600 BC), the first dynasty of China. Here, we report on proton-induced X-ray emission analyses of 118 proto-porcelain and 35 impressed stoneware sherds from Piaoshan and five subsequent kiln sites in the vicinity. Using principal components analysis on the major chemical compositions, we reveal the relationships between impressed stoneware and proto-porcelain samples from the six kiln sites. The sherds from different sites have distinctive chemical profiles. The results indicate that the raw materials were procured locally. We find a developmental tendency for early glazes towards mature calcium-based glaze. It is most likely that woody plant ashes with increased calcia-potash ratios were applied to the formula. PMID:26535583

The Earliest Chinese Proto-Porcelain Excavated from Kiln Sites: An Elemental Analysis.

PubMed

Li, Yu; Zhang, Bin; Cheng, Huansheng; Zheng, Jianming

2015-01-01

In June 2012, the Piaoshan kiln site was excavated in Huzhou, Zhejiang Province, which hitherto proved to be the earliest known Chinese proto-porcelain kiln. Judging from the decorative patterns of unearthed impressed stoneware and proto-porcelain sherds, the site was determined to date to the late Xia (c. 2070-c. 1600 BC), the first dynasty of China. Here, we report on proton-induced X-ray emission analyses of 118 proto-porcelain and 35 impressed stoneware sherds from Piaoshan and five subsequent kiln sites in the vicinity. Using principal components analysis on the major chemical compositions, we reveal the relationships between impressed stoneware and proto-porcelain samples from the six kiln sites. The sherds from different sites have distinctive chemical profiles. The results indicate that the raw materials were procured locally. We find a developmental tendency for early glazes towards mature calcium-based glaze. It is most likely that woody plant ashes with increased calcia-potash ratios were applied to the formula.

Effect of Electric Field Gradient on Sub-nanometer Spatial Resolution of Tip-enhanced Raman Spectroscopy

PubMed Central

Meng, Lingyan; Yang, Zhilin; Chen, Jianing; Sun, Mengtao

2015-01-01

Tip-enhanced Raman spectroscopy (TERS) with sub-nanometer spatial resolution has been recently demonstrated experimentally. However, the physical mechanism underlying is still under discussion. Here we theoretically investigate the electric field gradient of a coupled tip-substrate system. Our calculations suggest that the ultra-high spatial resolution of TERS can be partially attributed to the electric field gradient effect owning to its tighter spatial confinement and sensitivity to the infrared (IR)-active of molecules. Particularly, in the case of TERS of flat-lying H2TBPP molecules,we find the electric field gradient enhancement is the dominating factor for the high spatial resolution, which qualitatively coincides with previous experimental report. Our theoretical study offers a new paradigm for understanding the mechanisms of the ultra-high spatial resolution demonstrated in tip-enhanced spectroscopy which is of importance but neglected. PMID:25784161

JGIXA - A software package for the calculation and fitting of grazing incidence X-ray fluorescence and X-ray reflectivity data for the characterization of nanometer-layers and ultra-shallow-implants

NASA Astrophysics Data System (ADS)

Ingerle, D.; Pepponi, G.; Meirer, F.; Wobrauschek, P.; Streli, C.

2016-04-01

Grazing incidence XRF (GIXRF) is a very surface sensitive, nondestructive analytical tool making use of the phenomenon of total external reflection of X-rays on smooth polished surfaces. In recent years the method experienced a revival, being a powerful tool for process analysis and control in the fabrication of semiconductor based devices. Due to the downscaling of the process size for semiconductor devices, junction depths as well as layer thicknesses are reduced to a few nanometers, i.e. the length scale where GIXRF is highly sensitive. GIXRF measures the X-ray fluorescence induced by an X-ray beam incident under varying grazing angles and results in angle dependent intensity curves. These curves are correlated to the layer thickness, depth distribution and mass density of the elements in the sample. But the evaluation of these measurements is ambiguous with regard to the exact distribution function for the implants as well as for the thickness and density of nanometer-thin layers. In order to overcome this ambiguity, GIXRF can be combined with X-ray reflectometry (XRR). This is straightforward, as both techniques use similar measurement procedures and the same fundamental physical principles can be used for a combined data evaluation strategy. Such a combined analysis removes ambiguities in the determined physical properties of the studied sample and, being a correlative spectroscopic method, also significantly reduces experimental uncertainties of the individual techniques. In this paper we report our approach to a correlative data analysis, based on a concurrent calculation and fitting of simultaneously recorded GIXRF and XRR data. Based on this approach we developed JGIXA (Java Grazing Incidence X-ray Analysis), a multi-platform software package equipped with a user-friendly graphic user interface (GUI) and offering various optimization algorithms. Software and data evaluation approach were benchmarked by characterizing metal and metal oxide layers on

Ultra-High Density Single Nanometer-Scale Anodic Alumina Nanofibers Fabricated by Pyrophosphoric Acid Anodizing

NASA Astrophysics Data System (ADS)

Kikuchi, Tatsuya; Nishinaga, Osamu; Nakajima, Daiki; Kawashima, Jun; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

2014-12-01

Anodic oxide fabricated by anodizing has been widely used for nanostructural engineering, but the nanomorphology is limited to only two oxides: anodic barrier and porous oxides. Therefore, the discovery of an additional anodic oxide with a unique nanofeature would expand the applicability of anodizing. Here we demonstrate the fabrication of a third-generation anodic oxide, specifically, anodic alumina nanofibers, by anodizing in a new electrolyte, pyrophosphoric acid. Ultra-high density single nanometer-scale anodic alumina nanofibers (1010 nanofibers/cm2) consisting of an amorphous, pure aluminum oxide were successfully fabricated via pyrophosphoric acid anodizing. The nanomorphologies of the anodic nanofibers can be controlled by the electrochemical conditions. Anodic tungsten oxide nanofibers can also be fabricated by pyrophosphoric acid anodizing. The aluminum surface covered by the anodic alumina nanofibers exhibited ultra-fast superhydrophilic behavior, with a contact angle of less than 1°, within 1 second. Such ultra-narrow nanofibers can be used for various nanoapplications including catalysts, wettability control, and electronic devices.

Nanometer-Scale Chemistry of a Calcite Biomineralization Template: Implications for Skeletal Composition and Nucleation

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

Branson, Oscar; Bonnin, Elisa A.; Perea, Daniel E.

Biomineralizing organisms exhibit exquisite control over skeletal morphology and composition. The promise of understanding and harnessing this feat of natural engineering has motivated an intense search for the mechanisms that direct in vivo mineral self-assembly. We used atom probe tomography, a sub-nanometer 3D chemical mapping technique, to examine the chemistry of a buried organic-mineral interface in biomineral calcite from a marine foraminifer. The chemical patterns at this interface capture the processes of early biomineralization, when the shape, mineralogy, and orientation of skeletal growth are initially established. Sodium is enriched by a factor of nine on the organic side of themore » interface. Based on this pattern, we suggest that sodium plays an integral role in early biomineralization, potentially altering interfacial energy to promote crystal nucleation, and that interactions between organic surfaces and electrolytes other than calcium or carbonate could be a crucial aspect of CaCO3 biomineralization.« less

Ultra-High Density Single Nanometer-Scale Anodic Alumina Nanofibers Fabricated by Pyrophosphoric Acid Anodizing

PubMed Central

Kikuchi, Tatsuya; Nishinaga, Osamu; Nakajima, Daiki; Kawashima, Jun; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.

2014-01-01

Anodic oxide fabricated by anodizing has been widely used for nanostructural engineering, but the nanomorphology is limited to only two oxides: anodic barrier and porous oxides. Therefore, the discovery of an additional anodic oxide with a unique nanofeature would expand the applicability of anodizing. Here we demonstrate the fabrication of a third-generation anodic oxide, specifically, anodic alumina nanofibers, by anodizing in a new electrolyte, pyrophosphoric acid. Ultra-high density single nanometer-scale anodic alumina nanofibers (1010 nanofibers/cm2) consisting of an amorphous, pure aluminum oxide were successfully fabricated via pyrophosphoric acid anodizing. The nanomorphologies of the anodic nanofibers can be controlled by the electrochemical conditions. Anodic tungsten oxide nanofibers can also be fabricated by pyrophosphoric acid anodizing. The aluminum surface covered by the anodic alumina nanofibers exhibited ultra-fast superhydrophilic behavior, with a contact angle of less than 1°, within 1 second. Such ultra-narrow nanofibers can be used for various nanoapplications including catalysts, wettability control, and electronic devices. PMID:25491282

Virtual rough samples to test 3D nanometer-scale scanning electron microscopy stereo photogrammetry.

PubMed

Villarrubia, J S; Tondare, V N; Vladár, A E

2016-01-01

The combination of scanning electron microscopy for high spatial resolution, images from multiple angles to provide 3D information, and commercially available stereo photogrammetry software for 3D reconstruction offers promise for nanometer-scale dimensional metrology in 3D. A method is described to test 3D photogrammetry software by the use of virtual samples-mathematical samples from which simulated images are made for use as inputs to the software under test. The virtual sample is constructed by wrapping a rough skin with any desired power spectral density around a smooth near-trapezoidal line with rounded top corners. Reconstruction is performed with images simulated from different angular viewpoints. The software's reconstructed 3D model is then compared to the known geometry of the virtual sample. Three commercial photogrammetry software packages were tested. Two of them produced results for line height and width that were within close to 1 nm of the correct values. All of the packages exhibited some difficulty in reconstructing details of the surface roughness.

Nanometer-Scale Chemistry of a Calcite Biomineralization Template: Implications for Skeletal Composition and Nucleation

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

Branson, Oscar; Bonnin, Elisa A.; Perea, Daniel E.

2016-10-28

Biomineralizing organisms exhibit exquisite control over skeletal morphology and composition. The promise of understanding and harnessing this feat of natural engineering has motivated an intense search for the mechanisms that direct in vivo mineral self-assembly. We used atom probe tomography, a sub-nanometer 3D chemical mapping technique, to examine the chemistry of a buried organic-mineral interface in biomineral calcite from a marine foraminifer. The chemical patterns at this interface capture the processes of early biomineralization, when the shape, mineralogy, and orientation of skeletal growth are initially established. Sodium is enriched by a factor of nine on the organic side of themore » interface. Based on this pattern, we suggest that sodium plays an integral role in early biomineralization, potentially altering interfacial energy to promote crystal nucleation, and that interactions between organic surfaces and electrolytes other than calcium or carbonate could be a crucial aspect of CaCO3 biomineralization.« less

Nanometer-Scale Chemistry of a Calcite Biomineralization Template: Implications for Skeletal Composition and Nucleation

DOE PAGES

Branson, Oscar; Bonnin, Elisa A.; Perea, Daniel E.; ...

2016-10-28

Biomineralizing organisms exhibit exquisite control over skeletal morphology and composition. The promise of understanding and harnessing this feat of natural engineering has motivated an intense search for the mechanisms that direct in vivo mineral self-assembly. We used atom probe tomography, a sub-nanometer 3D chemical mapping technique, to examine the chemistry of a buried organic-mineral interface in biomineral calcite from a marine foraminifer. Here, the chemical patterns at this interface capture the processes of early biomineralization, when the shape, mineralogy, and orientation of skeletal growth are initially established. Sodium is enriched by a factor of nine on the organic side ofmore » the interface. Based on this pattern, we suggest that sodium plays an integral role in early biomineralization, potentially altering interfacial energy to promote crystal nucleation, and that interactions between organic surfaces and electrolytes other than calcium or carbonate could be a crucial aspect of CaCO 3 biomineralization.« less

Engineering polyelectrolyte multilayer structure at the nanometer length scale by tuning polymer solution conformation.

NASA Astrophysics Data System (ADS)

Boddohi, Soheil; Killingsworth, Christopher; Kipper, Matt

2008-03-01

Chitosan (a weak polycation) and heparin (a strong polyanion) are used to make polyelectrolyte multilayers (PEM). PEM thickness and composition are determined as a function of solution pH (4.6 to 5.8) and ionic strength (0.1 to 0.5 M). Over this range, increasing pH increases the PEM thickness; however, the sensitivity to changes in pH is a strong function of ionic strength. The PEM thickness data are correlated to the polymer conformation in solution. Polyelectrolyte conformation in solution is characterized by gel permeation chromatography (GPC). The highest sensitivity of PEM structure to pH is obtained at intermediate ionic strength. Different interactions govern the conformation and adsorption phenomena at low and high ionic strength, leading to reduced sensitivity to solution pH at extreme ionic strengths. The correspondence between PEM thickness and polymer solution conformation offers opportunities to tune polymer thin film structure at the nanometer length scale by controlling simple, reproducible processing conditions.

Nanometer-scale water- and proton-diffusion heterogeneities across water channels in polymer electrolyte membranes.

PubMed

Song, Jinsuk; Han, Oc Hee; Han, Songi

2015-03-16

Nafion, the most widely used polymer for electrolyte membranes (PEMs) in fuel cells, consists of a fluorocarbon backbone and acidic groups that, upon hydration, swell to form percolated channels through which water and ions diffuse. Although the effects of the channel structures and the acidic groups on water/ion transport have been studied before, the surface chemistry or the spatially heterogeneous diffusivity across water channels has never been shown to directly influence water/ion transport. By the use of molecular spin probes that are selectively partitioned into heterogeneous regions of the PEM and Overhauser dynamic nuclear polarization relaxometry, this study reveals that both water and proton diffusivity are significantly faster near the fluorocarbon and the acidic groups lining the water channels than within the water channels. The concept that surface chemistry at the (sub)nanometer scale dictates water and proton diffusivity invokes a new design principle for PEMs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The electrostatic fluidic trap: a new approach to the spatial control and manipulation of matter at the nanometer scale (presentation video)

NASA Astrophysics Data System (ADS)

Krishnan, Madhavi

2014-09-01

I will describe a new technique to trap matter at the nanometer scale in fluids. Rather than apply external fields to the object of interest, our approach relies on spatial tailoring of the interaction between an object and its neighbouring surfaces in order to create spatial potential minima in three dimensions. We demonstrate how the strong and long-ranged electrostatic interaction can be modulated by tailoring substrate geometry to achieve stable spatial trapping of charged objects, as small as single proteins in solution.

Maintenance Plan for the Composite Analysis of the Hanford Site, Southeast Washington.

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

Lehman, L. L.; Nichols, W. E.

The U.S. Department of Energy (DOE) manuals for radioactive waste management, DOE M 435.1-1 Chg 21 and DOE-STD-5002-2017, require that the Hanford Site maintain site performance assessments and composite analyses (CAs). This document describes the plan for maintaining the CA that supports waste disposal and remedial actions for the Hanford Site. An initial CA of the site was issued in 1998, conditionally approved in 1999, received further analysis to satisfy conditions in an addendum in 2001, and was approved in 2002. This document meets the maintenance plan requirements described in DOE M 435.1-1 Chg 2 and DOE-STD-5002-2017 and implements themore » requirements of the disposal authorization related to the CA for the U.S. Department of Energy, Richland Operations Office, the responsible field office, and its contractors.« less

TEMPORAL EVOLUTION OF SUB-NANOMETER COMPOSITIONAL PROFILES ACROSS THE GAMMA/GAMMA' INTERFACE IN A MODEL Ni-Al-Cr SUPERALLOY

NASA Technical Reports Server (NTRS)

Sudbrack, Chantal K.; Noebe, Ronald D.; Seidman, David N.

2005-01-01

Early-stage phase separation in a Ni-5.2 Al-14.2 Cr at.% superalloy, isothermally decomposing at 873 K, is investigated with atom-probe tomography. Sub-nanometer scale compositional profiles across the gamma/gamma'(L12) interfaces demonstrate that both the gamma-matrix and the gamma'-precipitate compositions evolve with time. Observed chemical gradients of Al depletion and Cr enrichment adjacent to the gamma'-precipitates are transient, consistent with well-established model predictions for diffusion-limited growth, and mark the first detailed observation of this phenomenon. Furthermore, it is shown that Cr atoms are kinetically trapped in the growing precipitates.

Baseline Ecological Risk Assessment for the Upland at the LCP Chemical Site, Brunswick, Georgia - Site Investigation/Analysis and Risk Characterization (Final)

EPA Pesticide Factsheets

Site Investigation/Analysis and Risk Characterization (Final) Prepared for Honeywell International Inc. Prepared by CDR Environmental Specialists, Inc. August 2010 Region ID: 04 DocID: 10746263, DocDate: 08-01-2010

Accredited hand surgery fellowship Web sites: analysis of content and accessibility.

PubMed

Trehan, Samir K; Morrell, Nathan T; Akelman, Edward

2015-04-01

To assess the accessibility and content of accredited hand surgery fellowship Web sites. A list of all accredited hand surgery fellowships was obtained from the online database of the American Society for Surgery of the Hand (ASSH). Fellowship program information on the ASSH Web site was recorded. All fellowship program Web sites were located via Google search. Fellowship program Web sites were analyzed for accessibility and content in 3 domains: program overview, application information/recruitment, and education. At the time of this study, there were 81 accredited hand surgery fellowships with 169 available positions. Thirty of 81 programs (37%) had a functional link on the ASSH online hand surgery fellowship directory; however, Google search identified 78 Web sites. Three programs did not have a Web site. Analysis of content revealed that most Web sites contained contact information, whereas information regarding the anticipated clinical, research, and educational experiences during fellowship was less often present. Furthermore, information regarding past and present fellows, salary, application process/requirements, call responsibilities, and case volume was frequently lacking. Overall, 52 of 81 programs (64%) had the minimal online information required for residents to independently complete the fellowship application process. Hand fellowship program Web sites could be accessed either via the ASSH online directory or Google search, except for 3 programs that did not have Web sites. Although most fellowship program Web sites contained contact information, other content such as application information/recruitment and education, was less frequently present. This study provides comparative data regarding the clinical and educational experiences outlined on hand fellowship program Web sites that are of relevance to residents, fellows, and academic hand surgeons. This study also draws attention to various ways in which the hand surgery fellowship application

GIS-based Landing-Site Analysis and Passive Decision Support

NASA Astrophysics Data System (ADS)

van Gasselt, Stephan; Nass, Andrea

2016-04-01

The increase of surface coverage and the availability and accessibility of planetary data allow researchers and engineers to remotely perform detailed studies on surface processes and properties, in particular on objects such as Mars and the Moon for which Terabytes of multi-temporal data at multiple spatial resolution levels have become available during the last 15 years. Orbiters, rovers and landers have been returning information and insights into the surface evolution of the terrestrial planets in unprecedented detail. While rover- and lander-based analyses are one major research aim to obtain ground truth, resource exploration or even potential establishment of bases using autonomous platforms are others and they require detailed investigation of settings in order to identify spots on the surface that are suitable for spacecraft to land and operate safely and over a long period of time. What has been done using hardcopy material in the past is today being carried by using either in-house developments or off-the-shelf spatial information system technology which allows to manage, integrate and analyse data as well as visualize and create user-defined reports for performing assessments. Usually, such analyses can be broken down (manually) by considering scientific wishes, engineering boundary conditions, potential hazards and various tertiary constraints. We here (1) review standard tasks of landing site analyses, (2) discuss issues inherently related to the analysis using integrated spatial analysis systems and (3) demonstrate a modular analysis framework for integration of data and for the evaluation of results from individual tasks in order to support decisions for landing-site selection.

Off-site training of laparoscopic skills, a scoping review using a thematic analysis.

PubMed

Thinggaard, Ebbe; Kleif, Jakob; Bjerrum, Flemming; Strandbygaard, Jeanett; Gögenur, Ismail; Matthew Ritter, E; Konge, Lars

2016-11-01

The focus of research in simulation-based laparoscopic training has changed from examining whether simulation training works to examining how best to implement it. In laparoscopic skills training, portable and affordable box trainers allow for off-site training. Training outside simulation centers and hospitals can increase access to training, but also poses new challenges to implementation. This review aims to guide implementation of off-site training of laparoscopic skills by critically reviewing the existing literature. An iterative systematic search was carried out in MEDLINE, EMBASE, ERIC, Scopus, and PsychINFO, following a scoping review methodology. The included literature was analyzed iteratively using a thematic analysis approach. The study was reported in accordance with the STructured apprOach to the Reporting In healthcare education of Evidence Synthesis statement. From the search, 22 records were identified and included for analysis. A thematic analysis revealed the themes: access to training, protected training time, distribution of training, goal setting and testing, task design, and unsupervised training. The identified themes were based on learning theories including proficiency-based learning, deliberate practice, and self-regulated learning. Methods of instructional design vary widely in off-site training of laparoscopic skills. Implementation can be facilitated by organizing courses and training curricula following sound education theories such as proficiency-based learning and deliberate practice. Directed self-regulated learning has the potential to improve off-site laparoscopic skills training; however, further studies are needed to demonstrate the effect of this type of instructional design.

Prediction of Protein Modification Sites of Pyrrolidone Carboxylic Acid Using mRMR Feature Selection and Analysis

PubMed Central

Zheng, Lu-Lu; Niu, Shen; Hao, Pei; Feng, KaiYan; Cai, Yu-Dong; Li, Yixue

2011-01-01

Pyrrolidone carboxylic acid (PCA) is formed during a common post-translational modification (PTM) of extracellular and multi-pass membrane proteins. In this study, we developed a new predictor to predict the modification sites of PCA based on maximum relevance minimum redundancy (mRMR) and incremental feature selection (IFS). We incorporated 727 features that belonged to 7 kinds of protein properties to predict the modification sites, including sequence conservation, residual disorder, amino acid factor, secondary structure and solvent accessibility, gain/loss of amino acid during evolution, propensity of amino acid to be conserved at protein-protein interface and protein surface, and deviation of side chain carbon atom number. Among these 727 features, 244 features were selected by mRMR and IFS as the optimized features for the prediction, with which the prediction model achieved a maximum of MCC of 0.7812. Feature analysis showed that all feature types contributed to the modification process. Further site-specific feature analysis showed that the features derived from PCA's surrounding sites contributed more to the determination of PCA sites than other sites. The detailed feature analysis in this paper might provide important clues for understanding the mechanism of the PCA formation and guide relevant experimental validations. PMID:22174779

Time Spent on Social Network Sites and Psychological Well-Being: A Meta-Analysis.

PubMed

Huang, Chiungjung

2017-06-01

This meta-analysis examines the relationship between time spent on social networking sites and psychological well-being factors, namely self-esteem, life satisfaction, loneliness, and depression. Sixty-one studies consisting of 67 independent samples involving 19,652 participants were identified. The mean correlation between time spent on social networking sites and psychological well-being was low at r = -0.07. The correlations between time spent on social networking sites and positive indicators (self-esteem and life satisfaction) were close to 0, whereas those between time spent on social networking sites and negative indicators (depression and loneliness) were weak. The effects of publication outlet, site on which users spent time, scale of time spent, and participant age and gender were not significant. As most included studies used student samples, future research should be conducted to examine this relationship for adults.

40 CFR 1400.5 - Internet access to certain off-site consequence analysis data elements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Internet access to certain off-site... DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS INFORMATION Public Access § 1400.5 Internet access to certain off... elements in the risk management plan database available on the Internet: (a) The concentration of the...

e-Ana and e-Mia: A Content Analysis of Pro–Eating Disorder Web Sites

PubMed Central

Schenk, Summer; Wilson, Jenny L.; Peebles, Rebecka

2010-01-01

Objectives. The Internet offers Web sites that describe, endorse, and support eating disorders. We examined the features of pro–eating disorder Web sites and the messages to which users may be exposed. Methods. We conducted a systematic content analysis of 180 active Web sites, noting site logistics, site accessories, “thinspiration” material (images and prose intended to inspire weight loss), tips and tricks, recovery, themes, and perceived harm. Results. Practically all (91%) of the Web sites were open to the public, and most (79%) had interactive features. A large majority (84%) offered pro-anorexia content, and 64% provided pro-bulimia content. Few sites focused on eating disorders as a lifestyle choice. Thinspiration material appeared on 85% of the sites, and 83% provided overt suggestions on how to engage in eating-disordered behaviors. Thirty-eight percent of the sites included recovery-oriented information or links. Common themes were success, control, perfection, and solidarity. Conclusions. Pro–eating disorder Web sites present graphic material to encourage, support, and motivate site users to continue their efforts with anorexia and bulimia. Continued monitoring will offer a valuable foundation to build a better understanding of the effects of these sites on their users. PMID:20558807

Application of the MIDAS approach for analysis of lysine acetylation sites.

PubMed

Evans, Caroline A; Griffiths, John R; Unwin, Richard D; Whetton, Anthony D; Corfe, Bernard M

2013-01-01

Multiple Reaction Monitoring Initiated Detection and Sequencing (MIDAS™) is a mass spectrometry-based technique for the detection and characterization of specific post-translational modifications (Unwin et al. 4:1134-1144, 2005), for example acetylated lysine residues (Griffiths et al. 18:1423-1428, 2007). The MIDAS™ technique has application for discovery and analysis of acetylation sites. It is a hypothesis-driven approach that requires a priori knowledge of the primary sequence of the target protein and a proteolytic digest of this protein. MIDAS essentially performs a targeted search for the presence of modified, for example acetylated, peptides. The detection is based on the combination of the predicted molecular weight (measured as mass-charge ratio) of the acetylated proteolytic peptide and a diagnostic fragment (product ion of m/z 126.1), which is generated by specific fragmentation of acetylated peptides during collision induced dissociation performed in tandem mass spectrometry (MS) analysis. Sequence information is subsequently obtained which enables acetylation site assignment. The technique of MIDAS was later trademarked by ABSciex for targeted protein analysis where an MRM scan is combined with full MS/MS product ion scan to enable sequence confirmation.

Effigy mound sites as cultural landscapes: A geophysical spatial analysis of two Late Woodland sites in southeastern Wisconsin

NASA Astrophysics Data System (ADS)

Kaufmann, Kira E.

This dissertation is a spatial analysis of a class of sacred sites known as Effigy Mounds during the Late Woodland period in southeast Wisconsin, circa A.D. 700--1100. Effigy Mounds are earthworks in the shape of animals, conical, linear, or geometric shapes. The research is focused on the upper Rock River Drainage in southern Wisconsin, a region where Effigy Mounds are very common. Although there are many theories concerning the meanings of Effigy Mounds, there is no cohesive description of Effigy Mounds as landscape elements and their function in the use of space by Late Woodland people. This research connects cultural and cognitive aspects of Native American cosmology with physical manifestations on the landscape. Effigy Mounds are examined from ideological and physical perspectives that are not mutually exclusive. Effigy Mounds are viewed as signifiers with multiple levels of function and meaning including sacred space, territorial markers, and mechanisms of social control and cohesion. Investigation at two Late Woodland Effigy Mound sites, Indian Mounds County Park in Jefferson County and Nitschke Mounds County Park in Dodge County, shows that landscape utilization varied significantly within and among Effigy Mound sites. An alternative model to understand Late Woodland Effigy Mound sites as ritual landscapes explores these features, their distribution across space, and the connection to internal site structures by synthesizing multidisciplinary data from historical ethnographic accounts, previous archaeological surveys, and new geophysical data. This multidisciplinary approach provides an example applicable to other landscape studies.

Combined Atomic Force Microscope-Based Topographical Imaging and Nanometer Scale Resolved Proximal Probe Thermal Desorption/Electrospray Ionization-Mass Spectrometry

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

Ovchinnikova, Olga S; Nikiforov, Maxim; Bradshaw, James A

2011-01-01

Nanometer scale proximal probe thermal desorption/electrospray ionization mass spectrometry (TD/ESI-MS) was demonstrated for molecular surface sampling of caffeine from a thin film using a 30 nm diameter nano-thermal analysis (nano-TA) probe tip in an atomic force microscope (AFM) coupled via a vapor transfer line and ESI interface to a MS detection platform. Using a probe temperature of 350 C and a spot sampling time of 30 s, conical desorption craters 250 nm in diameter and 100 nm deep were created as shown through subsequent topographical imaging of the surface within the same system. Automated sampling of a 5 x 2more » array of spots, with 2 m spacing between spots, and real time selective detection of the desorbed caffeine using tandem mass spectrometry was also demonstrated. Estimated from the crater volume (~2x106 nm3), only about 10 amol (2 fg) of caffeine was liberated from each thermal desorption crater in the thin film. These results illustrate a relatively simple experimental setup and means to acquire in automated fashion sub-micrometer scale spatial sampling resolution and mass spectral detection of materials amenable to TD. The ability to achieve MS-based chemical imaging with 250 nm scale spatial resolution with this system is anticipated.« less

Nanometer scale composition study of MBE grown BGaN performed by atom probe tomography

NASA Astrophysics Data System (ADS)

Bonef, Bastien; Cramer, Richard; Speck, James S.

2017-06-01

Laser assisted atom probe tomography is used to characterize the alloy distribution in BGaN. The effect of the evaporation conditions applied on the atom probe specimens on the mass spectrum and the quantification of the III site atoms is first evaluated. The evolution of the Ga++/Ga+ charge state ratio is used to monitor the strength of the applied field. Experiments revealed that applying high electric fields on the specimen results in the loss of gallium atoms, leading to the over-estimation of boron concentration. Moreover, spatial analysis of the surface field revealed a significant loss of atoms at the center of the specimen where high fields are applied. A good agreement between X-ray diffraction and atom probe tomography concentration measurements is obtained when low fields are applied on the tip. A random distribution of boron in the BGaN layer grown by molecular beam epitaxy is obtained by performing accurate and site specific statistical distribution analysis.

230Th/U ages Supporting Hanford Site-Wide Probabilistic Seismic Hazard Analysis

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

Paces, James B.

This product represents a USGS Administrative Report that discusses samples and methods used to conduct uranium-series isotope analyses and resulting ages and initial 234U/238U activity ratios of pedogenic cements developed in several different surfaces in the Hanford area middle to late Pleistocene. Samples were collected and dated to provide calibration of soil development in surface deposits that are being used in the Hanford Site-Wide probabilistic seismic hazard analysis conducted by AMEC. The report includes description of sample locations and physical characteristics, sample preparation, chemical processing and mass spectrometry, analytical results, and calculated ages for individual sites. Ages of innermost rindsmore » on a number of samples from five sites in eastern Washington are consistent with a range of minimum depositional ages from 17 ka for cataclysmic flood deposits to greater than 500 ka for alluvium at several sites.« less

The LivePhoto Physics videos and video analysis site

NASA Astrophysics Data System (ADS)

Abbott, David

2009-09-01

The LivePhoto site is similar to an archive of short films for video analysis. Some videos have Flash tools for analyzing the video embedded in the movie. Most of the videos address mechanics topics with titles like Rolling Pencil (check this one out for pedagogy and content knowledge—nicely done!), Juggler, Yo-yo, Puck and Bar (this one is an inelastic collision with rotation), but there are a few titles in other areas (E&M, waves, thermo, etc.).

Achieving diffraction-limited nanometer-scale X-ray point focus with two crossed multilayer Laue lenses: alignment challenges

DOE PAGES

Yan, Hanfei; Huang, Xiaojing; Bouet, Nathalie; ...

2017-10-16

In this article, we discuss misalignment-induced aberrations in a pair of crossed multilayer Laue lenses used for achieving a nanometer-scale x-ray point focus. We thoroughly investigate the impacts of two most important contributions, the orthogonality and the separation distance between two lenses. We find that misalignment in the orthogonality results in astigmatism at 45º and other inclination angles when coupled with a separation distance error. Theoretical explanation and experimental verification are provided. We show that to achieve a diffraction-limited point focus, accurate alignment of the azimuthal angle is required to ensure orthogonality between two lenses, and the required accuracy ismore » scaled with the ratio of the focus size to the aperture size.« less

APPLICATIONS ANALYSIS REPORT: SITE PROGRAM DEMONSTRATION TEST SOLIDITECH, INC. SOLIDIFICATION/ STABILIZATION PROCESS

EPA Science Inventory

This Applications Analysis Report evaluates the Soliditech, Inc., solidification/ stabilization process for the on-site treatment of waste materials. The Soliditech process mixes and chemically treats waste material with Urrichem (a proprietary reagent), additives, pozzolanic mat...

Critical radionuclide/critical pathway analysis for the U.S. Department of Energy's Savannah River Site.

PubMed

Jannik, G T

1999-06-01

Many different radionuclides have been released to the environment from the Savannah River Site (SRS) during the facility's operational history. However, as shown by this analysis, only a small number of the released radionuclides have been significant contributors to potential doses and risks to off-site people. This article documents the radiological critical contaminant/critical pathway analysis performed for SRS. If site missions and operations remain constant over the next 30 years, only tritium oxide releases are projected to exceed a maximally exposed individual (MEI) risk of 1.0E-06 for either the airborne or liquid pathways. The critical exposure pathways associated with site airborne releases are inhalation and vegetation consumption, whereas the critical exposure pathways associated with liquid releases are drinking water and fish consumption. For the SRS-specific, nontypical exposure pathways (i.e., recreational fishing and deer and hog hunting), cesium-137 is the critical radionuclide.

Applying fault tree analysis to the prevention of wrong-site surgery.

PubMed

Abecassis, Zachary A; McElroy, Lisa M; Patel, Ronak M; Khorzad, Rebeca; Carroll, Charles; Mehrotra, Sanjay

2015-01-01

Wrong-site surgery (WSS) is a rare event that occurs to hundreds of patients each year. Despite national implementation of the Universal Protocol over the past decade, development of effective interventions remains a challenge. We performed a systematic review of the literature reporting root causes of WSS and used the results to perform a fault tree analysis to assess the reliability of the system in preventing WSS and identifying high-priority targets for interventions aimed at reducing WSS. Process components where a single error could result in WSS were labeled with OR gates; process aspects reinforced by verification were labeled with AND gates. The overall redundancy of the system was evaluated based on prevalence of AND gates and OR gates. In total, 37 studies described risk factors for WSS. The fault tree contains 35 faults, most of which fall into five main categories. Despite the Universal Protocol mandating patient verification, surgical site signing, and a brief time-out, a large proportion of the process relies on human transcription and verification. Fault tree analysis provides a standardized perspective of errors or faults within the system of surgical scheduling and site confirmation. It can be adapted by institutions or specialties to lead to more targeted interventions to increase redundancy and reliability within the preoperative process. Copyright © 2015 Elsevier Inc. All rights reserved.

Characterization of nanometer-thick polycrystalline silicon with phonon-boundary scattering enhanced thermoelectric properties and its application in infrared sensors.

PubMed

Zhou, Huchuan; Kropelnicki, Piotr; Lee, Chengkuo

2015-01-14

Although significantly reducing the thermal conductivity of silicon nanowires has been reported, it remains a challenge to integrate silicon nanowires with structure materials and electrodes in the complementary metal-oxide-semiconductor (CMOS) process. In this paper, we investigated the thermal conductivity of nanometer-thick polycrystalline silicon (poly-Si) theoretically and experimentally. By leveraging the phonon-boundary scattering, the thermal conductivity of 52 nm thick poly-Si was measured as low as around 12 W mK(-1) which is only about 10% of the value of bulk single crystalline silicon. The ZT of n-doped and p-doped 52 nm thick poly-Si was measured as 0.067 and 0.024, respectively, while most previously reported data had values of about 0.02 and 0.01 for a poly-Si layer with a thickness of 0.5 μm and above. Thermopile infrared sensors comprising 128 pairs of thermocouples made of either n-doped or p-doped nanometer-thick poly-Si strips in a series connected by an aluminium (Al) metal interconnect layer are fabricated using microelectromechanical system (MEMS) technology. The measured vacuum specific detectivity (D*) of the n-doped and p-doped thermopile infrared (IR) sensors are 3.00 × 10(8) and 1.83 × 10(8) cm Hz(1/2) W(-1) for sensors of 52 nm thick poly-Si, and 5.75 × 10(7) and 3.95 × 10(7) cm Hz(1/2) W(-1) for sensors of 300 nm thick poly-Si, respectively. The outstanding thermoelectric properties indicate our approach is promising for diverse applications using ultrathin poly-Si technology.

Silicifying Biofilm Exopolymers on a Hot-Spring Microstromatolite: Templating Nanometer-Thick Laminae

NASA Astrophysics Data System (ADS)

Handley, Kim M.; Turner, Sue J.; Campbell, Kathleen A.; Mountain, Bruce W.

2008-08-01

Exopolymeric substances (EPS) are an integral component of microbial biofilms; however, few studies have addressed their silicification and preservation in hot-spring deposits. Through comparative analyses with the use of a range of microscopy techniques, we identified abundant EPS significant to the textural development of spicular, microstromatolitic, siliceous sinter at Champagne Pool, Waiotapu, New Zealand. Examination of biofilms coating sinter surfaces by confocal laser scanning microscopy (CLSM), environmental scanning electron microscopy (ESEM), cryo-scanning electron microscopy (cryo-SEM), and transmission electron microscopy (TEM) revealed contraction of the gelatinous EPS matrix into films (approximately 10 nm thick) or fibrillar structures, which is common in conventional SEM analyses and analogous to products of naturally occurring desiccation. Silicification of fibrillar EPS contributed to the formation of filamentous sinter. Matrix surfaces or dehydrated films templated sinter laminae (nanometers to microns thick) that, in places, preserved fenestral voids beneath. Laminae of similar thickness are, in general, common to spicular geyserites. This is the first report to demonstrate EPS templation of siliceous stromatolite laminae. Considering the ubiquity of biofilms on surfaces in hot-spring environments, EPS silicification studies are likely to be important to a better understanding of the origins of laminae in other modern and ancient stromatolitic sinters, and EPS potentially may serve as biosignatures in extraterrestrial rocks.

Droplet-counting Microtitration System for Precise On-site Analysis.

PubMed

Kawakubo, Susumu; Omori, Taichi; Suzuki, Yasutada; Ueta, Ikuo

2018-01-01

A new microtitration system based on the counting of titrant droplets has been developed for precise on-site analysis. The dropping rate was controlled by inserting a capillary tube as a flow resistance in a laboratory-made micropipette. The error of titration was 3% in a simulated titration with 20 droplets. The pre-addition of a titrant was proposed for precise titration within an error of 0.5%. The analytical performances were evaluated for chelate titration, redox titration and acid-base titration.

Food and beverage brands that market to children and adolescents on the internet: a content analysis of branded web sites.

PubMed

Henry, Anna E; Story, Mary

2009-01-01

To identify food and beverage brand Web sites featuring designated children's areas, assess marketing techniques present on those industry Web sites, and determine nutritional quality of branded food items marketed to children. Systematic content analysis of food and beverage brand Web sites and nutrient analysis of food and beverages advertised on these Web sites. The World Wide Web. One-hundred thirty Internet Web sites of food and beverage brands with top media expenditures based on the America's Top 2000 Brands section of Brandweek magazine's annual "Superbrands" report. A standardized content analysis rating form to determine marketing techniques used on the food and beverage brand Web sites. Nutritional analysis of food brands was conducted. Of 130 Web sites analyzed, 48% featured designated children's areas. These Web sites featured a variety of Internet marketing techniques, including advergaming on 85% of the Web sites and interactive programs on 92% of the Web sites. Branded spokescharacters and tie-ins to other products were featured on the majority of the Web sites, as well. Few food brands (13%) with Web sites that market to children met the nutrition criteria set by the National Alliance for Nutrition and Activity. Nearly half of branded Web sites analyzed used designated children's areas to market food and beverages to children, 87% of which were of low nutritional quality. Nutrition professionals should advocate the use of advertising techniques to encourage healthful food choices for children.

Selection of remedial alternatives for mine sites: a multicriteria decision analysis approach.

PubMed

Betrie, Getnet D; Sadiq, Rehan; Morin, Kevin A; Tesfamariam, Solomon

2013-04-15

The selection of remedial alternatives for mine sites is a complex task because it involves multiple criteria and often with conflicting objectives. However, an existing framework used to select remedial alternatives lacks multicriteria decision analysis (MCDA) aids and does not consider uncertainty in the selection of alternatives. The objective of this paper is to improve the existing framework by introducing deterministic and probabilistic MCDA methods. The Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) methods have been implemented in this study. The MCDA analysis involves processing inputs to the PROMETHEE methods that are identifying the alternatives, defining the criteria, defining the criteria weights using analytical hierarchical process (AHP), defining the probability distribution of criteria weights, and conducting Monte Carlo Simulation (MCS); running the PROMETHEE methods using these inputs; and conducting a sensitivity analysis. A case study was presented to demonstrate the improved framework at a mine site. The results showed that the improved framework provides a reliable way of selecting remedial alternatives as well as quantifying the impact of different criteria on selecting alternatives. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Nanometer-Sized Eutectic Structure of Si/CrSi2 Thermoelectric Materials Fabricated by Rapid Solidification

NASA Astrophysics Data System (ADS)

Norizan, Mohd Natashah; Miyazaki, Yoshinobu; Ohishi, Yuji; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

2018-04-01

Nanostructuring is known to be an effective method to improve thermoelectric performance but, generally, it requires complex procedures and much labor. In the present study, self-assembled nanometer-sized composite structures of silicon (Si) and chromium disilicide (CrSi2) were easily fabricated by the rapid solidification of a melt with a eutectic composition. Ribbon-like samples were obtained with a dominant nanostructure of fine aligned lamellae with a spacing range of 20-35 nm. The thermoelectric power factor of the ribbon was observed to be 1.2 mW/mK2 at room temperature and reached 3.0 mW/mK2 at 773 K. The thermal conductivity was 65% lower than that of a bulk eutectic sample. The results suggest that this method is promising for fabricating an effective nanostructure for thermoelectric performance.

Multivariate analysis of mixed contaminants (PAHs and heavy metals) at manufactured gas plant site soils.

PubMed

Thavamani, Palanisami; Megharaj, Mallavarapu; Naidu, Ravi

2012-06-01

Principal component analysis (PCA) was used to provide an overview of the distribution pattern of polycyclic aromatic hydrocarbons (PAHs) and heavy metals in former manufactured gas plant (MGP) site soils. PCA is the powerful multivariate method to identify the patterns in data and expressing their similarities and differences. Ten PAHs (naphthalene, acenapthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo[a]pyrene) and four toxic heavy metals - lead (Pb), cadmium (Cd), chromium (Cr) and zinc (Zn) - were detected in the site soils. PAH contamination was contributed equally by both low and high molecular weight PAHs. PCA was performed using the varimax rotation method in SPSS, 17.0. Two principal components accounting for 91.7% of the total variance was retained using scree test. Principle component 1 (PC1) substantially explained the dominance of PAH contamination in the MGP site soils. All PAHs, except anthracene, were positively correlated in PC1. There was a common thread in high molecular weight PAHs loadings, where the loadings were inversely proportional to the hydrophobicity and molecular weight of individual PAHs. Anthracene, which was less correlated with other individual PAHs, deviated well from the origin which can be ascribed to its lower toxicity and different origin than its isomer phenanthrene. Among the four major heavy metals studied in MGP sites, Pb, Cd and Cr were negatively correlated in PC1 but showed strong positive correlation in principle component 2 (PC2). Although metals may not have originated directly from gaswork processes, the correlation between PAHs and metals suggests that the materials used in these sites may have contributed to high concentrations of Pb, Cd, Cr and Zn. Thus, multivariate analysis helped to identify the sources of PAHs, heavy metals and their association in MGP site, and thereby better characterise the site risk, which would not be possible if one uses chemical analysis

Functional nanometer-scale structures

NASA Astrophysics Data System (ADS)

Chan, Tsz On Mario

Nanometer-scale structures have properties that are fundamentally different from their bulk counterparts. Much research effort has been devoted in the past decades to explore new fabrication techniques, model the physical properties of these structures, and construct functional devices. The ability to manipulate and control the structure of matter at the nanoscale has made many new classes of materials available for the study of fundamental physical processes and potential applications. The interplay between fabrication techniques and physical understanding of the nanostructures and processes has revolutionized the physical and material sciences, providing far superior properties in materials for novel applications that benefit society. This thesis consists of two major aspects of my graduate research in nano-scale materials. In the first part (Chapters 3--6), a comprehensive study on the nanostructures based on electrospinning and thermal treatment is presented. Electrospinning is a well-established method for producing high-aspect-ratio fibrous structures, with fiber diameter ranging from 1 nm--1 microm. A polymeric solution is typically used as a precursor in electrospinning. In our study, the functionality of the nanostructure relies on both the nanostructure and material constituents. Metallic ions containing precursors were added to the polymeric precursor following a sol-gel process to prepare the solution suitable for electrospinning. A typical electrospinning process produces as-spun fibers containing both polymer and metallic salt precursors. Subsequent thermal treatments of the as-spun fibers were carried out in various conditions to produce desired structures. In most cases, polymer in the solution and the as-spun fibers acted as a backbone for the structure formation during the subsequent heat treatment, and were thermally removed in the final stage. Polymers were also designed to react with the metallic ion precursors during heat treatment in some

Computer analysis of protein functional sites projection on exon structure of genes in Metazoa

PubMed Central

2015-01-01

Background Study of the relationship between the structural and functional organization of proteins and their coding genes is necessary for an understanding of the evolution of molecular systems and can provide new knowledge for many applications for designing proteins with improved medical and biological properties. It is well known that the functional properties of proteins are determined by their functional sites. Functional sites are usually represented by a small number of amino acid residues that are distantly located from each other in the amino acid sequence. They are highly conserved within their functional group and vary significantly in structure between such groups. According to this facts analysis of the general properties of the structural organization of the functional sites at the protein level and, at the level of exon-intron structure of the coding gene is still an actual problem. Results One approach to this analysis is the projection of amino acid residue positions of the functional sites along with the exon boundaries to the gene structure. In this paper, we examined the discontinuity of the functional sites in the exon-intron structure of genes and the distribution of lengths and phases of the functional site encoding exons in vertebrate genes. We have shown that the DNA fragments coding the functional sites were in the same exons, or in close exons. The observed tendency to cluster the exons that code functional sites which could be considered as the unit of protein evolution. We studied the characteristics of the structure of the exon boundaries that code, and do not code, functional sites in 11 Metazoa species. This is accompanied by a reduced frequency of intercodon gaps (phase 0) in exons encoding the amino acid residue functional site, which may be evidence of the existence of evolutionary limitations to the exon shuffling. Conclusions These results characterize the features of the coding exon-intron structure that affect the

Computer analysis of protein functional sites projection on exon structure of genes in Metazoa.

PubMed

Medvedeva, Irina V; Demenkov, Pavel S; Ivanisenko, Vladimir A

2015-01-01

Study of the relationship between the structural and functional organization of proteins and their coding genes is necessary for an understanding of the evolution of molecular systems and can provide new knowledge for many applications for designing proteins with improved medical and biological properties. It is well known that the functional properties of proteins are determined by their functional sites. Functional sites are usually represented by a small number of amino acid residues that are distantly located from each other in the amino acid sequence. They are highly conserved within their functional group and vary significantly in structure between such groups. According to this facts analysis of the general properties of the structural organization of the functional sites at the protein level and, at the level of exon-intron structure of the coding gene is still an actual problem. One approach to this analysis is the projection of amino acid residue positions of the functional sites along with the exon boundaries to the gene structure. In this paper, we examined the discontinuity of the functional sites in the exon-intron structure of genes and the distribution of lengths and phases of the functional site encoding exons in vertebrate genes. We have shown that the DNA fragments coding the functional sites were in the same exons, or in close exons. The observed tendency to cluster the exons that code functional sites which could be considered as the unit of protein evolution. We studied the characteristics of the structure of the exon boundaries that code, and do not code, functional sites in 11 Metazoa species. This is accompanied by a reduced frequency of intercodon gaps (phase 0) in exons encoding the amino acid residue functional site, which may be evidence of the existence of evolutionary limitations to the exon shuffling. These results characterize the features of the coding exon-intron structure that affect the functionality of the encoded protein and

Multivariate analysis of early and late nest sites of Abert's Towhees

Treesearch

Deborah M. Finch

1985-01-01

Seasonal variation in nest site selection by the Abert's towhee (Pipilo aberti) was studied in honey mesquite (Prosopis glandulosa) habitat along the lower Colorado River from March to July, 1981. Stepwise discriminant function analysis identified nest vegetation type, nest direction, and nest height as the three most important variables that characterized the...

Binding Sites Analyser (BiSA): Software for Genomic Binding Sites Archiving and Overlap Analysis

PubMed Central

Khushi, Matloob; Liddle, Christopher; Clarke, Christine L.; Graham, J. Dinny

2014-01-01

Genome-wide mapping of transcription factor binding and histone modification reveals complex patterns of interactions. Identifying overlaps in binding patterns by different factors is a major objective of genomic studies, but existing methods to archive large numbers of datasets in a personalised database lack sophistication and utility. Therefore we have developed transcription factor DNA binding site analyser software (BiSA), for archiving of binding regions and easy identification of overlap with or proximity to other regions of interest. Analysis results can be restricted by chromosome or base pair overlap between regions or maximum distance between binding peaks. BiSA is capable of reporting overlapping regions that share common base pairs; regions that are nearby; regions that are not overlapping; and average region sizes. BiSA can identify genes located near binding regions of interest, genomic features near a gene or locus of interest and statistical significance of overlapping regions can also be reported. Overlapping results can be visualized as Venn diagrams. A major strength of BiSA is that it is supported by a comprehensive database of publicly available transcription factor binding sites and histone modifications, which can be directly compared to user data. The documentation and source code are available on http://bisa.sourceforge.net PMID:24533055

Three-dimensional integrated circuits for lab-on-chip dielectrophoresis of nanometer scale particles

NASA Astrophysics Data System (ADS)

Dickerson, Samuel J.; Noyola, Arnaldo J.; Levitan, Steven P.; Chiarulli, Donald M.

2007-01-01

In this paper, we present a mixed-technology micro-system for electronically manipulating and optically detecting virusscale particles in fluids that is designed using 3D integrated circuit technology. During the 3D fabrication process, the top-most chip tier is assembled upside down and the substrate material is removed. This places the polysilicon layer, which is used to create geometries with the process' minimum feature size, in close proximity to a fluid channel etched into the top of the stack. By taking advantage of these processing features inherent to "3D chip-stacking" technology, we create electrode arrays that have a gap spacing of 270 nm. Using 3D CMOS technology also provides the ability to densely integrate analog and digital control circuitry for the electrodes by using the additional levels of the chip stack. We show simulations of the system with a physical model of a Kaposi's sarcoma-associated herpes virus, which has a radius of approximately 125 nm, being dielectrophoretically arranged into striped patterns. We also discuss how these striped patterns of trapped nanometer scale particles create an effective diffraction grating which can then be sensed with macro-scale optical techniques.

Research and design on orthogonal diffraction grating-based 3D nanometer displacement sensor

NASA Astrophysics Data System (ADS)

Liu, Baoshuai; Yuan, Yibao; Yin, Zhehao

2017-10-01

This study concerns an orthogonal diffraction grating-based nanometer displacement sensor. In this study, we performed calculation of displacements in the XYZ directions. In the optical measured path part, we used a two-dimensional orthogonal motion grating and a two-dimensional orthogonal reference grating with the pitch of 0.5um to measure the displacement of XYZ in three directions by detecting ±1st diffraction fringes. The self-collimated structure of the grating greatly extended the Z-axis range. We also simulated the optical path of the sensor with ZEMAX software and verified the feasibility of the scheme. For signal subdivision and processing, we combined large number counting (completed grating line) with small number counting (digital subdivision), realizing high multiples of subdivision of grating interference signals. We used PC to process the interference fringes and greatly improved the processing speed. In the scheme, the theoretical multiples of subdivision could reach 1024 with 10-bit AD conversion, but the actual multiples of subdivision was limited by the quality of the grating interference signals. So we introduced an orthogonal compensation circuit and a filter circuit to improve the signal quality.

Hanford Site Composite Analysis Technical Approach Description: Groundwater Pathway Dose Calculation.

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

Morgans, D. L.; Lindberg, S. L.

The purpose of this technical approach document (TAD) is to document the assumptions, equations, and methods used to perform the groundwater pathway radiological dose calculations for the revised Hanford Site Composite Analysis (CA). DOE M 435.1-1, states, “The composite analysis results shall be used for planning, radiation protection activities, and future use commitments to minimize the likelihood that current low-level waste disposal activities will result in the need for future corrective or remedial actions to adequately protect the public and the environment.”

Comparative Bioinformatic Analysis of Active Site Structures in Evolutionarily Remote Homologues of α,β-Hydrolase Superfamily Enzymes.

PubMed

Suplatov, D A; Arzhanik, V K; Svedas, V K

2011-01-01

Comparative bioinformatic analysis is the cornerstone of the study of enzymes' structure-function relationship. However, numerous enzymes that derive from a common ancestor and have undergone substantial functional alterations during natural selection appear not to have a sequence similarity acceptable for a statistically reliable comparative analysis. At the same time, their active site structures, in general, can be conserved, while other parts may largely differ. Therefore, it sounds both plausible and appealing to implement a comparative analysis of the most functionally important structural elements - the active site structures; that is, the amino acid residues involved in substrate binding and the catalytic mechanism. A computer algorithm has been developed to create a library of enzyme active site structures based on the use of the PDB database, together with programs of structural analysis and identification of functionally important amino acid residues and cavities in the enzyme structure. The proposed methodology has been used to compare some α,β-hydrolase superfamily enzymes. The insight has revealed a high structural similarity of catalytic site areas, including the conservative organization of a catalytic triad and oxyanion hole residues, despite the wide functional diversity among the remote homologues compared. The methodology can be used to compare the structural organization of the catalytic and substrate binding sites of various classes of enzymes, as well as study enzymes' evolution and to create of a databank of enzyme active site structures.

Marine environmental protection: An application of the nanometer photo catalyst method on decomposition of benzene.

PubMed

Lin, Mu-Chien; Kao, Jui-Chung

2016-04-15

Bioremediation is currently extensively employed in the elimination of coastal oil pollution, but it is not very effective as the process takes several months to degrade oil. Among the components of oil, benzene degradation is difficult due to its stable characteristics. This paper describes an experimental study on the decomposition of benzene by titanium dioxide (TiO2) nanometer photocatalysis. The photocatalyst is illuminated with 360-nm ultraviolet light for generation of peroxide ions. This results in complete decomposition of benzene, thus yielding CO2 and H2O. In this study, a nonwoven fabric is coated with the photocatalyst and benzene. Using the Double-Shot Py-GC system on the residual component, complete decomposition of the benzene was verified by 4h of exposure to ultraviolet light. The method proposed in this study can be directly applied to elimination of marine oil pollution. Further studies will be conducted on coastal oil pollution in situ. Copyright © 2016 Elsevier Ltd. All rights reserved.

Triangulating the source of tunneling resonances in a point contact with nanometer scale sensitivity

NASA Astrophysics Data System (ADS)

Bishop, N. C.; Boras Pinilla, C.; Stalford, H. L.; Young, R. W.; Ten Eyck, G. A.; Wendt, J. R.; Eng, K.; Lilly, M. P.; Carroll, M. S.

2011-03-01

We observe resonant tunneling in split gate point contacts defined in a double gate enhancement mode Si-MOS device structure. We determine the capacitances from the resonant feature to each of the conducting gates and the source/drain two dimensional electron gas regions. In our device, these capacitances provide information about the resonance location in three dimensions. Semi-classical electrostatic simulations of capacitance, already used to map quantum dot size and position [Stalford et al., IEEE Nanotechnology], identify a combination of location and confinement potential size that satisfy our experimental observations. The sensitivity of simulation to position and size allow us to triangulate possible locations of the resonant level with nanometer resolution. We discuss our results and how they may apply to resonant tunneling through a single donor. This work was supported by the Laboratory Directed Research and Development program at Sandia National Laboratories. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Interdiffusion in nanometer-scale multilayers investigated by in situ low-angle x-ray diffraction

NASA Astrophysics Data System (ADS)

Wang, Wei-Hua; Bai, Hai Yang; Zhang, Ming; Zhao, J. H.; Zhang, X. Y.; Wang, W. K.

1999-04-01

An in situ low-angle x-ray diffraction technique is used to investigate interdiffusion phenomena in various metal-metal and metal-amorphous Si nanometer-scale compositionally modulated multilayers (ML's). The temperature-dependent interdiffusivities are obtained by accurately monitoring the decay of the first-order modulation peak as a function of annealing time. Activation enthalpies and preexponential factors for the interdiffusion in the Fe-Ti, Ag-Bi, Fe-Mo, Mo-Si, Ni-Si, Nb-Si, and Ag-Si ML's are determined. Activation enthalpies and preexponential factors for the interdiffusion in the ML's are very small compared with that in amorphous alloys and crystalline solids. The relation between the atomic-size difference and interdiffusion in the ML's are investigated. The observed interdiffusion characteristics are compared with that in amorphous alloys and crystalline α-Zr, α-Ti, and Si. The experimental results suggest that a collective atomic-jumping mechanism govern the interdiffusion in the ML's, the collective proposal involving 8-15 atoms moving between extended nonequilibrium defects by thermal activation. The role of the interdiffusion in the solid-state reaction in the ML's is also discussed.

Control of the interaction strength of photonic molecules by nanometer precise 3D fabrication.

PubMed

Rawlings, Colin D; Zientek, Michal; Spieser, Martin; Urbonas, Darius; Stöferle, Thilo; Mahrt, Rainer F; Lisunova, Yuliya; Brugger, Juergen; Duerig, Urs; Knoll, Armin W

2017-11-28

Applications for high resolution 3D profiles, so-called grayscale lithography, exist in diverse fields such as optics, nanofluidics and tribology. All of them require the fabrication of patterns with reliable absolute patterning depth independent of the substrate location and target materials. Here we present a complete patterning and pattern-transfer solution based on thermal scanning probe lithography (t-SPL) and dry etching. We demonstrate the fabrication of 3D profiles in silicon and silicon oxide with nanometer scale accuracy of absolute depth levels. An accuracy of less than 1nm standard deviation in t-SPL is achieved by providing an accurate physical model of the writing process to a model-based implementation of a closed-loop lithography process. For transfering the pattern to a target substrate we optimized the etch process and demonstrate linear amplification of grayscale patterns into silicon and silicon oxide with amplification ratios of ∼6 and ∼1, respectively. The performance of the entire process is demonstrated by manufacturing photonic molecules of desired interaction strength. Excellent agreement of fabricated and simulated structures has been achieved.

Synthesis of Highly Active Sub-Nanometer Pt@Rh Core-Shell Nanocatalyst via a Photochemical Route: Porous Titania Nanoplates as a Superior Photoactive Support.

PubMed

Zhan, Wen-Wen; Zhu, Qi-Long; Dang, Song; Liu, Zheng; Kitta, Mitsunori; Suenaga, Kazutomo; Zheng, Lan-Sun; Xu, Qiang

2017-04-01

Sub-nanometer Pt@Rh nanoparticles highly dispersed on MIL-125-derived porous TiO 2 nanoplates are successfully prepared for the first time by a photochemical route, where the porous TiO 2 nanoplates with a relatively high specific surface area play a dual role as both effective photoreductant and catalyst support. The resulting Pt@Rh/p-TiO 2 can be utilized as a highly active catalyst. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cluster analysis of S. Cerevisiae nucleosome binding sites

NASA Astrophysics Data System (ADS)

Suvorova, Y.; Korotkov, E.

2017-12-01

It is well known that major part of a eukaryotic genome is wrapped around histone proteins forming nucleosomes. It was also demonstrated that the DNA sequence itself is playing an important role in the nucleosome positioning process. In this work, a cluster analysis of 67 517 nucleosome binding sites from the S. Cerevisiae genome was carried out. The classification method is based on the self-adjusting dinucleotides position weight matrix. As a result, 135 significant clusters were discovered that contain 43225 sequences (which constitutes 64% of the initial set). The meaning of the found classes is discussed, as well as the possibility of the further usage.

Analysis of Vlbi, Slr and GPS Site Position Time Series

NASA Astrophysics Data System (ADS)

Angermann, D.; Krügel, M.; Meisel, B.; Müller, H.; Tesmer, V.

Conventionally the IERS terrestrial reference frame (ITRF) is realized by the adoption of a set of epoch coordinates and linear velocities for a set of global tracking stations. Due to the remarkable progress of the space geodetic observation techniques (e.g. VLBI, SLR, GPS) the accuracy and consistency of the ITRF increased continuously. The accuracy achieved today is mainly limited by technique-related systematic errors, which are often poorly characterized or quantified. Therefore it is essential to analyze the individual techniques' solutions with respect to systematic differences, models, parameters, datum definition, etc. Main subject of this presentation is the analysis of GPS, SLR and VLBI time series of site positions. The investigations are based on SLR and VLBI solutions computed at DGFI with the software systems DOGS (SLR) and OCCAM (VLBI). The GPS time series are based on weekly IGS station coordinates solutions. We analyze the time series with respect to the issues mentioned above. In particular we characterize the noise in the time series, identify periodic signals, and investigate non-linear effects that complicate the assignment of linear velocities for global tracking sites. One important aspect is the comparison of results obtained by different techniques at colocation sites.

Bidirectional Retroviral Integration Site PCR Methodology and Quantitative Data Analysis Workflow.

PubMed

Suryawanshi, Gajendra W; Xu, Song; Xie, Yiming; Chou, Tom; Kim, Namshin; Chen, Irvin S Y; Kim, Sanggu

2017-06-14

Integration Site (IS) assays are a critical component of the study of retroviral integration sites and their biological significance. In recent retroviral gene therapy studies, IS assays, in combination with next-generation sequencing, have been used as a cell-tracking tool to characterize clonal stem cell populations sharing the same IS. For the accurate comparison of repopulating stem cell clones within and across different samples, the detection sensitivity, data reproducibility, and high-throughput capacity of the assay are among the most important assay qualities. This work provides a detailed protocol and data analysis workflow for bidirectional IS analysis. The bidirectional assay can simultaneously sequence both upstream and downstream vector-host junctions. Compared to conventional unidirectional IS sequencing approaches, the bidirectional approach significantly improves IS detection rates and the characterization of integration events at both ends of the target DNA. The data analysis pipeline described here accurately identifies and enumerates identical IS sequences through multiple steps of comparison that map IS sequences onto the reference genome and determine sequencing errors. Using an optimized assay procedure, we have recently published the detailed repopulation patterns of thousands of Hematopoietic Stem Cell (HSC) clones following transplant in rhesus macaques, demonstrating for the first time the precise time point of HSC repopulation and the functional heterogeneity of HSCs in the primate system. The following protocol describes the step-by-step experimental procedure and data analysis workflow that accurately identifies and quantifies identical IS sequences.

Kinetic analysis of bypass of abasic site by the catalytic core of yeast DNA polymerase eta.

PubMed

Yang, Juntang; Wang, Rong; Liu, Binyan; Xue, Qizhen; Zhong, Mengyu; Zeng, Hao; Zhang, Huidong

2015-09-01

Abasic sites (Apurinic/apyrimidinic (AP) sites), produced ∼ 50,000 times/cell/day, are very blocking and miscoding. To better understand miscoding mechanisms of abasic site for yeast DNA polymerase η, pre-steady-state nucleotide incorporation and LC-MS/MS sequence analysis of extension product were studied using pol η(core) (catalytic core, residues 1-513), which can completely eliminate the potential effects of the C-terminal C2H2 motif of pol η on dNTP incorporation. The extension beyond the abasic site was very inefficient. Compared with incorporation of dCTP opposite G, the incorporation efficiencies opposite abasic site were greatly reduced according to the order of dGTP > dATP > dCTP and dTTP. Pol η(core) showed no fast burst phase for any incorporation opposite G or abasic site, suggesting that the catalytic step is not faster than the dissociation of polymerase from DNA. LC-MS/MS sequence analysis of extension products showed that 53% products were dGTP misincorporation, 33% were dATP and 14% were -1 frameshift, indicating that Pol η(core) bypasses abasic site by a combined G-rule, A-rule and -1 frameshift deletions. Compared with full-length pol η, pol η(core) relatively reduced the efficiency of incorporation of dCTP opposite G, increased the efficiencies of dNTP incorporation opposite abasic site and the exclusive incorporation of dGTP opposite abasic site, but inhibited the extension beyond abasic site, and increased the priority in extension of A: abasic site relative to G: abasic site. This study provides further understanding in the mutation mechanism of abasic sites for yeast DNA polymerase η. Copyright © 2015 Elsevier B.V. All rights reserved.

Food and Beverage Brands that Market to Children and Adolescents on the Internet: A Content Analysis of Branded Web Sites

ERIC Educational Resources Information Center

Henry, Anna E.; Story, Mary

2009-01-01

Objective: To identify food and beverage brand Web sites featuring designated children's areas, assess marketing techniques present on those industry Web sites, and determine nutritional quality of branded food items marketed to children. Design: Systematic content analysis of food and beverage brand Web sites and nutrient analysis of food and…

Analysis of Recent European Surface Ozone Trends Considering Site Representativeness and Mete-orology

NASA Astrophysics Data System (ADS)

Henne, S.; Fleming, Z.; Brunner, D.; Klausen, J.; Buchmann, B.

2009-04-01

Recent trends of surface ozone (O3) within Europe vary substantially depending on the location and surroundings of a measurement site. The influence of long-range transport from North America and Asia, changes in stratosphere-troposphere exchange, increase in lower stratospheric O3 and changes in advection patterns are possible drivers for the observed O3 trends. O3 concentrations greatly depend on meteorology (temperature and radiation) and local to regional emissions of precursor gases and therefore on the representativeness of a site (e.g. background vs. urban site) and regional emission trends. We investigated the representativeness of 1264 "rural" and "suburban" background sites (as available through the European Environment Agency (EEA )Airbase database) by analysing population density, land cover and topography in the surrounding of the sites. A hierarchical clustering method was applied to derive an independent site categorization. The two area types as specified by EEA are split into 7 categories: elevated, lowered, remote, rural, rural/coastal, rural/polluted, suburban. Furthermore, we analysed the trend of surface O3 and Ox (O3+NO2) for the mentioned sites based on the above site categorization, local meteorology and precursor emission trends. Of the 1264 sites 161 possess sufficiently long and complete O3 data series suitable for robust trend estimation, while for 100 sites both O3 and NO2 data are available. We present a strategy for further data exclusion based on available data quality information and a break detection algorithm. First results of the trend analysis applying different statistical approaches are discussed.

Methylated site display (MSD)-AFLP, a sensitive and affordable method for analysis of CpG methylation profiles.

PubMed

Aiba, Toshiki; Saito, Toshiyuki; Hayashi, Akiko; Sato, Shinji; Yunokawa, Harunobu; Maruyama, Toru; Fujibuchi, Wataru; Kurita, Hisaka; Tohyama, Chiharu; Ohsako, Seiichiroh

2017-03-09

It has been pointed out that environmental factors or chemicals can cause diseases that are developmental in origin. To detect abnormal epigenetic alterations in DNA methylation, convenient and cost-effective methods are required for such research, in which multiple samples are processed simultaneously. We here present methylated site display (MSD), a unique technique for the preparation of DNA libraries. By combining it with amplified fragment length polymorphism (AFLP) analysis, we developed a new method, MSD-AFLP. Methylated site display libraries consist of only DNAs derived from DNA fragments that are CpG methylated at the 5' end in the original genomic DNA sample. To test the effectiveness of this method, CpG methylation levels in liver, kidney, and hippocampal tissues of mice were compared to examine if MSD-AFLP can detect subtle differences in the levels of tissue-specific differentially methylated CpGs. As a result, many CpG sites suspected to be tissue-specific differentially methylated were detected. Nucleotide sequences adjacent to these methyl-CpG sites were identified and we determined the methylation level by methylation-sensitive restriction endonuclease (MSRE)-PCR analysis to confirm the accuracy of AFLP analysis. The differences of the methylation level among tissues were almost identical among these methods. By MSD-AFLP analysis, we detected many CpGs showing less than 5% statistically significant tissue-specific difference and less than 10% degree of variability. Additionally, MSD-AFLP analysis could be used to identify CpG methylation sites in other organisms including humans. MSD-AFLP analysis can potentially be used to measure slight changes in CpG methylation level. Regarding the remarkable precision, sensitivity, and throughput of MSD-AFLP analysis studies, this method will be advantageous in a variety of epigenetics-based research.

Geological and Geochemical Analysis of Seabed Stability at the Norfolk Ocean Disposal Site. Part 1: Geological Analysis.

DTIC Science & Technology

1983-05-31

ANALYSIS OF SEABED STABILITY AT THE NORFOLK OCEAN DISPOSAL SITE PART 1: GEOLOGICAL ANALYSIS U LU D George F. Oertel, Principal Investigator i- Final Report...eC.it ,ie _. _ r. .. .... All e d !t-o i’~$ ~- - - • ° . .. • : " . o . . . , . . ... - . • , .. . . . . . kkN 4. 18. parameters, diver reconnaissance of...For the period ending September 30, 1982 Prepared for the Department of the Army Norfolk District, Corps of Engineers 803 Front Street D I *Norfolk

Differential optical shadow sensor for sub-nanometer displacement measurement and its application to drag-free satellites.

PubMed

Zoellner, Andreas; Tan, Si; Saraf, Shailendhar; Alfauwaz, Abdul; DeBra, Dan; Buchman, Sasha; Lipa, John A

2017-10-16

We present a method for 3D sub-nanometer displacement measurement using a set of differential optical shadow sensors. It is based on using pairs of collimated beams on opposite sides of an object that are partially blocked by it. Applied to a sphere, our 3-axis sensor module consists of 8 parallel beam-detector sets for redundancy. The sphere blocks half of each beam's power in the nominal centered position, and any displacement can be measured by the differential optical power changes amongst the pairs of detectors. We have experimentally demonstrated a displacement sensitivity of 0.87nm/Hz at 1 Hz and 0.39nm/Hz at 10 Hz. We describe the application of the module to the inertial sensor of a drag-free satellite, which can potentially be used for navigation, geodesy and fundamental science experiments as well as ground based applications.

Analysis of zinc binding sites in protein crystal structures.

PubMed

Alberts, I L; Nadassy, K; Wodak, S J

1998-08-01

The geometrical properties of zinc binding sites in a dataset of high quality protein crystal structures deposited in the Protein Data Bank have been examined to identify important differences between zinc sites that are directly involved in catalysis and those that play a structural role. Coordination angles in the zinc primary coordination sphere are compared with ideal values for each coordination geometry, and zinc coordination distances are compared with those in small zinc complexes from the Cambridge Structural Database as a guide of expected trends. We find that distances and angles in the primary coordination sphere are in general close to the expected (or ideal) values. Deviations occur primarily for oxygen coordinating atoms and are found to be mainly due to H-bonding of the oxygen coordinating ligand to protein residues, bidentate binding arrangements, and multi-zinc sites. We find that H-bonding of oxygen containing residues (or water) to zinc bound histidines is almost universal in our dataset and defines the elec-His-Zn motif. Analysis of the stereochemistry shows that carboxyl elec-His-Zn motifs are geometrically rigid, while water elec-His-Zn motifs show the most geometrical variation. As catalytic motifs have a higher proportion of carboxyl elec atoms than structural motifs, they provide a more rigid framework for zinc binding. This is understood biologically, as a small distortion in the zinc position in an enzyme can have serious consequences on the enzymatic reaction. We also analyze the sequence pattern of the zinc ligands and residues that provide elecs, and identify conserved hydrophobic residues in the endopeptidases that also appear to contribute to stabilizing the catalytic zinc site. A zinc binding template in protein crystal structures is derived from these observations.

Analysis of Material Handling Safety in Construction Sites and Countermeasures for Effective Enhancement

PubMed Central

Anil Kumar, C. N.; Sakthivel, M.; Elangovan, R. K.; Arularasu, M.

2015-01-01

One of many hazardous workplaces includes the construction sites as they involve several dangerous tasks. Many studies have revealed that material handling equipment is a major cause of accidents at these sites. Though safety measures are being followed and monitored continuously, accident rates are still high as either workers are unaware of hazards or the safety regulations are not being strictly followed. This paper analyses the safety management systems at construction sites through means of questionnaire surveys with employees, specifically referring to safety of material handling equipment. Based on results of the questionnaire surveys, two construction sites were selected for a safety education program targeting worker safety related to material handling equipment. Knowledge levels of the workers were gathered before and after the program and results obtained were subjected to a t-test analysis to mark significance level of the conducted safety education program. PMID:26446572

Sub-nanometer surface chemistry and orbital hybridization in lanthanum-doped ceria nano-catalysts revealed by 3D electron microscopy.

PubMed

Collins, Sean M; Fernandez-Garcia, Susana; Calvino, José J; Midgley, Paul A

2017-07-14

Surface chemical composition, electronic structure, and bonding characteristics determine catalytic activity but are not resolved for individual catalyst particles by conventional spectroscopy. In particular, the nano-scale three-dimensional distribution of aliovalent lanthanide dopants in ceria catalysts and their effect on the surface electronic structure remains unclear. Here, we reveal the surface segregation of dopant cations and oxygen vacancies and observe bonding changes in lanthanum-doped ceria catalyst particle aggregates with sub-nanometer precision using a new model-based spectroscopic tomography approach. These findings refine our understanding of the spatially varying electronic structure and bonding in ceria-based nanoparticle aggregates with aliovalent cation concentrations and identify new strategies for advancing high efficiency doped ceria nano-catalysts.

Egypt's Red Sea coast: phylogenetic analysis of cultured microbial consortia in industrialized sites.

PubMed

Mustafa, Ghada A; Abd-Elgawad, Amr; Abdel-Haleem, Alyaa M; Siam, Rania

2014-01-01

The Red Sea possesses a unique geography, and its shores are rich in mangrove, macro-algal and coral reef ecosystems. Various sources of pollution affect Red Sea biota, including microbial life. We assessed the effects of industrialization on microbes along the Egyptian Red Sea coast at eight coastal sites and two lakes. The bacterial communities of sediment samples were analyzed using bacterial 16S rDNA pyrosequencing of V6-V4 hypervariable regions. The taxonomic assignment of 131,402 significant reads to major bacterial taxa revealed five main bacterial phyla dominating the sampled sites: Proteobacteria (68%), Firmicutes (13%), Fusobacteria (12%), Bacteriodetes (6%), and Spirochetes (0.03%). Further analysis revealed distinct bacterial consortia that primarily included (1) marine Vibrio spp.-suggesting a "marine Vibrio phenomenon"; (2) potential human pathogens; and (3) oil-degrading bacteria. We discuss two divergent microbial consortia that were sampled from Solar Lake West near Taba/Eilat and Saline Lake in Ras Muhammad; these consortia contained the highest abundance of human pathogens and no pathogens, respectively. Our results draw attention to the effects of industrialization on the Red Sea and suggest the need for further analysis to overcome the hazardous effects observed at the impacted sites.

Selection of Atmospheric Environmental Monitoring Sites based on Geographic Parameters Extraction of GIS and Fuzzy Matter-Element Analysis.

PubMed

Wu, Jianfa; Peng, Dahao; Ma, Jianhao; Zhao, Li; Sun, Ce; Ling, Huanzhang

2015-01-01

To effectively monitor the atmospheric quality of small-scale areas, it is necessary to optimize the locations of the monitoring sites. This study combined geographic parameters extraction by GIS with fuzzy matter-element analysis. Geographic coordinates were extracted by GIS and transformed into rectangular coordinates. These coordinates were input into the Gaussian plume model to calculate the pollutant concentration at each site. Fuzzy matter-element analysis, which is used to solve incompatible problems, was used to select the locations of sites. The matter element matrices were established according to the concentration parameters. The comprehensive correlation functions KA (xj) and KB (xj), which reflect the degree of correlation among monitoring indices, were solved for each site, and a scatter diagram of the sites was drawn to determine the final positions of the sites based on the functions. The sites could be classified and ultimately selected by the scatter diagram. An actual case was tested, and the results showed that 5 positions can be used for monitoring, and the locations conformed to the technical standard. In the results of this paper, the hierarchical clustering method was used to improve the methods. The sites were classified into 5 types, and 7 locations were selected. Five of the 7 locations were completely identical to the sites determined by fuzzy matter-element analysis. The selections according to these two methods are similar, and these methods can be used in combination. In contrast to traditional methods, this study monitors the isolated point pollutant source within a small range, which can reduce the cost of monitoring.

Probabilistic seismic hazard analysis for a nuclear power plant site in southeast Brazil

NASA Astrophysics Data System (ADS)

de Almeida, Andréia Abreu Diniz; Assumpção, Marcelo; Bommer, Julian J.; Drouet, Stéphane; Riccomini, Claudio; Prates, Carlos L. M.

2018-05-01

A site-specific probabilistic seismic hazard analysis (PSHA) has been performed for the only nuclear power plant site in Brazil, located 130 km southwest of Rio de Janeiro at Angra dos Reis. Logic trees were developed for both the seismic source characterisation and ground-motion characterisation models, in both cases seeking to capture the appreciable ranges of epistemic uncertainty with relatively few branches. This logic-tree structure allowed the hazard calculations to be performed efficiently while obtaining results that reflect the inevitable uncertainty in long-term seismic hazard assessment in this tectonically stable region. An innovative feature of the study is an additional seismic source zone added to capture the potential contributions of characteristics earthquake associated with geological faults in the region surrounding the coastal site.

The Synergistic Effect of Leukocyte Platelet-Rich Fibrin and Micrometer/Nanometer Surface Texturing on Bone Healing around Immediately Placed Implants: An Experimental Study in Dogs

PubMed Central

Neiva, Rodrigo F.; Gil, Luiz Fernando; Tovar, Nick; Janal, Malvin N.; Marao, Heloisa Fonseca; Pinto, Nelson; Coelho, Paulo G.

2016-01-01

Aims. This study evaluated the effects of L-PRF presence and implant surface texture on bone healing around immediately placed implants. Methods. The first mandibular molars of 8 beagle dogs were bilaterally extracted, and implants (Blossom™, Intra-Lock International, Boca Raton, FL) were placed in the mesial or distal extraction sockets in an interpolated fashion per animal. Two implant surfaces were distributed per sockets: (1) dual acid-etched (DAE, micrometer scale textured) and (2) micrometer/nanometer scale textured (Ossean™ surface). L-PRF (Intraspin system, Intra-Lock International) was placed in a split-mouth design to fill the macrogap between implant and socket walls on one side of the mandible. The contralateral side received implants without L-PRF. A mixed-model ANOVA (at α = 0.05) evaluated the effect of implant surface, presence of L-PRF, and socket position (mesial or distal), individually or in combination on bone area fraction occupancy (BAFO). Results. BAFO values were significantly higher for the Ossean relative to the DAE surface on the larger mesial socket. The presence of L-PRF resulted in higher BAFO. The Ossean surface and L-PRF presence resulted in significantly higher BAFO. Conclusion. L-PRF and the micro-/nanometer scale textured surface resulted in increased bone formation around immediately placed implants. PMID:28042577

Probabilistic Risk Analysis of Groundwater Related Problems in Subterranean Excavation Sites

NASA Astrophysics Data System (ADS)

Sanchez-Vila, X.; Jurado, A.; de Gaspari, F.; Vilarrasa, V.; Bolster, D.; Fernandez-Garcia, D.; Tartakovsky, D. M.

2009-12-01

Construction of subterranean excavations in densely populated areas is inherently hazardous. The number of construction sites (e.g., subway lines, railways and highway tunnels) has increased in recent years. These sites can pose risks to workers at the site as well as cause damage to surrounding buildings. The presence of groundwater makes the excavation even more complicated. We develop a probabilistic risk assessment (PRA) model o estimate the likelihood of occurrence of certain risks during a subway station construction. While PRA is widely used in many engineering fields, its applications to the underground constructions in general and to an underground station construction in particular are scarce if not nonexistent. This method enables us not only to evaluate the probability of failure, but also to quantify the uncertainty of the different events considered. The risk analysis was carried out using a fault tree analysis that made it possible to study a complex system in a structured and straightforward manner. As an example we consider an underground station for the new subway line in the Barcelona metropolitan area (Línia 9) through the town of Prat de Llobregat in the Llobregat River Delta, which is currently under development. A typical station on the L9 line lies partially between the shallow and the main aquifer. Specifically, it is located in the middle layer which is made up of silts and clays. By presenting this example we aim to illustrate PRA as an effective methodology for estimating and minimising risks and to demonstrate its utility as a potential tool for decision making.

Analysis and prediction of Multiple-Site Damage (MSD) fatigue crack growth

NASA Technical Reports Server (NTRS)

Dawicke, D. S.; Newman, J. C., Jr.

1992-01-01

A technique was developed to calculate the stress intensity factor for multiple interacting cracks. The analysis was verified through comparison with accepted methods of calculating stress intensity factors. The technique was incorporated into a fatigue crack growth prediction model and used to predict the fatigue crack growth life for multiple-site damage (MSD). The analysis was verified through comparison with experiments conducted on uniaxially loaded flat panels with multiple cracks. Configuration with nearly equal and unequal crack distribution were examined. The fatigue crack growth predictions agreed within 20 percent of the experimental lives for all crack configurations considered.

Low-cost, high-precision micro-lensed optical fiber providing deep-micrometer to deep-nanometer-level light focusing.

PubMed

Wen, Sy-Bor; Sundaram, Vijay M; McBride, Daniel; Yang, Yu

2016-04-15

A new type of micro-lensed optical fiber through stacking appropriate high-refractive microspheres at designed locations with respect to the cleaved end of an optical fiber is numerically and experimentally demonstrated. This new type of micro-lensed optical fiber can be precisely constructed with low cost and high speed. Deep micrometer-scale and submicrometer-scale far-field light spots can be achieved when the optical fibers are multimode and single mode, respectively. By placing an appropriate teardrop dielectric nanoscale scatterer at the far-field spot of this new type of micro-lensed optical fiber, a deep-nanometer near-field spot can also be generated with high intensity and minimum joule heating, which is valuable in high-speed, high-resolution, and high-power nanoscale detection compared with traditional near-field optical fibers containing a significant portion of metallic material.

A needs analysis method for land-use planning of illegal dumping sites: a case study in Aomori-Iwate, Japan.

PubMed

Ishii, Kazuei; Furuichi, Toru; Nagao, Yukari

2013-02-01

Land use at contaminated sites, following remediation, is often needed for regional redevelopment. However, there exist few methods of developing economically and socially feasible land-use plans based on regional needs because of the wide variety of land-use requirements. This study proposes a new needs analysis method for the conceptual land-use planning of contaminated sites and illustrates this method with a case study of an illegal dumping site for hazardous waste. In this method, planning factors consisting of the land-use attributes and related facilities are extracted from the potential needs of the residents through a preliminary questionnaire. Using the extracted attributes of land use and the related facilities, land-use cases are designed for selection-based conjoint analysis. A second questionnaire for respondents to the first one who indicated an interest in participating in the second questionnaire is conducted for the conjoint analysis to determine the utility function and marginal cost of each attribute in order to prioritize the planning factors to develop a quantitative and economically and socially feasible land-use plan. Based on the results, site-specific land-use alternatives are developed and evaluated by the utility function obtained from the conjoint analysis. In this case study of an illegal dumping site for hazardous waste, the uses preferred as part of a conceptual land-use plan following remediation of the site were (1) agricultural land and a biogas plant designed to recover energy from biomass or (2) a park with a welfare facility and an athletic field. Our needs analysis method with conjoint analysis is applicable to the development of conceptual land-use planning for similar sites following remediation, particularly when added value is considered. Copyright © 2012 Elsevier Ltd. All rights reserved.

'Fram' in Color

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site] Click on the image for 'Fram' in Color (QTVR)

This view in approximately true color reveals details in an impact crater informally named 'Fram' in the Meridian Planum region of Mars. The picture is a mosaic of frames taken by the panoramic camera on NASA's Mars Exploration Rover Opportunity during the rover's 88th martian day on Mars, on April 23, 2004. The crater spans about 8 meters (26 feet) in diameter. Opportunity paused beside it while traveling from the rover's landing site toward a larger crater farther east. This view combines images taken using three of the camera's filters for different wavelengths of light: 750 nanometers, 530 nanometers and 430 nanometers.

GIS Based Multi-Criteria Decision Analysis For Cement Plant Site Selection For Cuddalore District

NASA Astrophysics Data System (ADS)

Chhabra, A.

2015-12-01

India's cement industry is a vital part of its economy, providing employment to more than a million people. On the back of growing demands, due to increased construction and infrastructural activities cement market in India is expected to grow at a compound annual growth rate (CAGR) of 8.96 percent during the period 2014-2019. In this study, GIS-based spatial Multi Criteria Decision Analysis (MCDA) is used to determine the optimum and alternative sites to setup a cement plant. This technique contains a set of evaluation criteria which are quantifiable indicators of the extent to which decision objectives are realized. In intersection with available GIS (Geographical Information System) and local ancillary data, the outputs of image analysis serves as input for the multi-criteria decision making system. Moreover, the following steps were performed so as to represent the criteria in GIS layers, which underwent the GIS analysis in order to get several potential sites. Satellite imagery from LANDSAT 8 and ASTER DEM were used for the analysis. Cuddalore District in Tamil Nadu was selected as the study site as limestone mining is already being carried out in that region which meets the criteria of raw material for cement production. Several other criteria considered were land use land cover (LULC) classification (built-up area, river, forest cover, wet land, barren land, harvest land and agriculture land), slope, proximity to road, railway and drainage networks.

Application of Microtremor Horizontal-to-Vertical Spectral Ratio (MHVSR) Analysis for Site Characterization: State of the Art

NASA Astrophysics Data System (ADS)

Molnar, S.; Cassidy, J. F.; Castellaro, S.; Cornou, C.; Crow, H.; Hunter, J. A.; Matsushima, S.; Sánchez-Sesma, F. J.; Yong, A.

2018-03-01

Nakamura (Q Rep Railway Tech Res Inst 30:25-33, 1989) popularized the application of the horizontal-to-vertical spectral ratio (HVSR) analysis of microtremor (seismic noise or ambient vibration) recordings to estimate the predominant frequency and amplification factor of earthquake shaking. During the following quarter century, popularity in the microtremor HVSR (MHVSR) method grew; studies have verified the stability of a site's MHVSR response over time and validated the MHVSR response with that of earthquake HVSR response. Today, MHVSR analysis is a popular reconnaissance tool used worldwide for seismic microzonation and earthquake site characterization in numerous regions, specifically, in the mapping of site period or fundamental frequency and inverted for shear-wave velocity depth profiles, respectively. However, the ubiquity of MHVSR analysis is predominantly a consequence of its ease in application rather than our full understanding of its theory. We present the state of the art in MHVSR analyses in terms of the development of its theoretical basis, current state of practice, and we comment on its future for applications in earthquake site characterization.

Application of Microtremor Horizontal-to-Vertical Spectral Ratio (MHVSR) Analysis for Site Characterization: State of the Art

NASA Astrophysics Data System (ADS)

Molnar, S.; Cassidy, J. F.; Castellaro, S.; Cornou, C.; Crow, H.; Hunter, J. A.; Matsushima, S.; Sánchez-Sesma, F. J.; Yong, A.

2018-07-01

Nakamura (Q Rep Railway Tech Res Inst 30:25-33, 1989) popularized the application of the horizontal-to-vertical spectral ratio (HVSR) analysis of microtremor (seismic noise or ambient vibration) recordings to estimate the predominant frequency and amplification factor of earthquake shaking. During the following quarter century, popularity in the microtremor HVSR (MHVSR) method grew; studies have verified the stability of a site's MHVSR response over time and validated the MHVSR response with that of earthquake HVSR response. Today, MHVSR analysis is a popular reconnaissance tool used worldwide for seismic microzonation and earthquake site characterization in numerous regions, specifically, in the mapping of site period or fundamental frequency and inverted for shear-wave velocity depth profiles, respectively. However, the ubiquity of MHVSR analysis is predominantly a consequence of its ease in application rather than our full understanding of its theory. We present the state of the art in MHVSR analyses in terms of the development of its theoretical basis, current state of practice, and we comment on its future for applications in earthquake site characterization.

Analysis of Site Position Time Series Derived From Space Geodetic Solutions

NASA Astrophysics Data System (ADS)

Angermann, D.; Meisel, B.; Kruegel, M.; Tesmer, V.; Miller, R.; Drewes, H.

2003-12-01

This presentation deals with the analysis of station coordinate time series obtained from VLBI, SLR, GPS and DORIS solutions. We also present time series for the origin and scale derived from these solutions and discuss their contribution to the realization of the terrestrial reference frame. For these investigations we used SLR and VLBI solutions computed at DGFI with the software systems DOGS (SLR) and OCCAM (VLBI). The GPS and DORIS time series were obtained from weekly station coordinates solutions provided by the IGS, and from the joint DORIS analysis center (IGN-JPL). We analysed the time series with respect to various aspects, such as non-linear motions, periodic signals and systematic differences (biases). A major focus is on a comparison of the results at co-location sites in order to identify technique- and/or solution related problems. This may also help to separate and quantify possible effects, and to understand the origin of still existing discrepancies. Technique-related systematic effects (biases) should be reduced to the highest possible extent, before using the space geodetic solutions for a geophysical interpretation of seasonal signals in site position time series.

Significant enhancement of magnetoresistance with the reduction of particle size in nanometer scale

PubMed Central

Das, Kalipada; Dasgupta, P.; Poddar, A.; Das, I.

2016-01-01

The Physics of materials with large magnetoresistance (MR), defined as the percentage change of electrical resistance with the application of external magnetic field, has been an active field of research for quite some times. In addition to the fundamental interest, large MR has widespread application that includes the field of magnetic field sensor technology. New materials with large MR is interesting. However it is more appealing to vast scientific community if a method describe to achieve many fold enhancement of MR of already known materials. Our study on several manganite samples [La1−xCaxMnO3 (x = 0.52, 0.54, 0.55)] illustrates the method of significant enhancement of MR with the reduction of the particle size in nanometer scale. Our experimentally observed results are explained by considering model consisted of a charge ordered antiferromagnetic core and a shell having short range ferromagnetic correlation between the uncompensated surface spins in nanoscale regime. The ferromagnetic fractions obtained theoretically in the nanoparticles has been shown to be in the good agreement with the experimental results. The method of several orders of magnitude improvement of the magnetoresistive property will have enormous potential for magnetic field sensor technology. PMID:26837285

Size-dependent elastic/inelastic behavior of enamel over millimeter and nanometer length scales.

PubMed

Ang, Siang Fung; Bortel, Emely L; Swain, Michael V; Klocke, Arndt; Schneider, Gerold A

2010-03-01

The microstructure of enamel like most biological tissues has a hierarchical structure which determines their mechanical behavior. However, current studies of the mechanical behavior of enamel lack a systematic investigation of these hierarchical length scales. In this study, we performed macroscopic uni-axial compression tests and the spherical indentation with different indenter radii to probe enamel's elastic/inelastic transition over four hierarchical length scales, namely: 'bulk enamel' (mm), 'multiple-rod' (10's microm), 'intra-rod' (100's nm with multiple crystallites) and finally 'single-crystallite' (10's nm with an area of approximately one hydroxyapatite crystallite). The enamel's elastic/inelastic transitions were observed at 0.4-17 GPa depending on the length scale and were compared with the values of synthetic hydroxyapatite crystallites. The elastic limit of a material is important as it provides insights into the deformability of the material before fracture. At the smallest investigated length scale (contact radius approximately 20 nm), elastic limit is followed by plastic deformation. At the largest investigated length scale (contact size approximately 2 mm), only elastic then micro-crack induced response was observed. A map of elastic/inelastic regions of enamel from millimeter to nanometer length scale is presented. Possible underlying mechanisms are also discussed. (c) 2009 Elsevier Ltd. All rights reserved.

Thermal and ultrasonic influence in the formation of nanometer scale hydroxyapatite bio-ceramic

PubMed Central

Poinern, GJE; Brundavanam, R; Le, X Thi; Djordjevic, S; Prokic, M; Fawcett, D

2011-01-01

Hydroxyapatite (HAP) is a widely used biocompatible ceramic in many biomedical applications and devices. Currently nanometer-scale forms of HAP are being intensely investigated due to their close similarity to the inorganic mineral component of the natural bone matrix. In this study nano-HAP was prepared via a wet precipitation method using Ca(NO3)2 and KH2PO4 as the main reactants and NH4OH as the precipitator under ultrasonic irradiation. The Ca/P ratio was set at 1.67 and the pH was maintained at 9 during the synthesis process. The influence of the thermal treatment was investigated by using two thermal treatment processes to produce ultrafine nano-HAP powders. In the first heat treatment, a conventional radiant tube furnace was used to produce nano-particles with an average size of approximately 30 nm in diameter, while the second thermal treatment used a microwave-based technique to produce particles with an average diameter of 36 nm. The crystalline structure and morphology of all nanoparticle powders produced were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). Both thermal techniques effectively produced ultrafine powders with similar crystalline structure, morphology and particle sizes. PMID:22114473

Full path compensation laser feedback interferometry for remote sensing with recovered nanometer resolutions

NASA Astrophysics Data System (ADS)

Xu, Ling; Tan, Yidong; Zhang, Shulian

2018-03-01

The accuracy of the existing laser feedback interferometry for measuring the remote target is limited to several microns due to environmental disturbances. A novel approach is presented in this paper based on the double-beam frequency-shift feedback of the laser, which can completely eliminate the dead path errors and measure the displacement or vibration with accuracy at nanometer scale even at a far measurement distance. The two beams emitted from one Nd:YVO4 crystal are incident on the measurement target and its adjacent reference surface, respectively. The reference surface could be taken from the nearby stationary object, without the need to put a reference mirror. The feedback paths and shift frequencies of the two beams are the same, so the air disturbances and the thermal effects in the way could be fully compensated. Under common room conditions, the displacement of a steel block at a distance of 10 m is measured, which proved that the system's stability is ±12 nm in 100 s and ±50 nm in 1000 s, the short-term resolution is better than 3 nm, and the linearity within the 300 mm range is 5 × 10-6 and within the 100 μm range is 1 × 10-4.

Revealing the cell-material interface with nanometer resolution by FIB-SEM

PubMed Central

Santoro, Francesca; Zhao, Wenting; Joubert, Lydia-Marie; Duan, Liting; Schnitker, Jan; van de Burgt, Yoeri; Lou, Hsin-Ya; Liu, Bofei; Salleo, Alberto; Cui, Lifeng; Cui, Yi; Cui, Bianxiao

2018-01-01

The interface between cells and non-biological surfaces regulates cell attachment, chronic tissue responses, and ultimately the success of medical implants or biosensors. Clinical and laboratory studies show that topological features of the surface profoundly influences cellular responses, e.g. titanium surfaces with nano- and microtopographical structures enhance osteoblast attachment and host-implant integration as compare to smooth surface. To understand how cells and tissues respond to different topographical features, it is of critical importance to directly visualize the cell-materials interface at the relevant nanometer length scale. Here, we present a new method for in situ examination of the cell-to-material interface at any desired location, based on focused-ion beam milling and scanning electron microscopy imaging (FIB-SEM) to resolve the cell membrane-to-material interface with 10 nm resolution. By examining how cell membranes interact with topographical features such as nanoscale protrusions or invaginations, we discovered that the cell membrane readily deforms inward and wraps around protruding structures, but hardly deforms outward to contour invaginating structures. This asymmetric membrane response (inward vs. outward deformation) causes the cleft width between the cell membrane and the nanostructure surface to vary for more than an order of magnitude. Our results suggest that surface topology is a crucial consideration for the development of medical implants or biosensors whose performances are strongly influenced by the cell-to-material interface. We anticipate that the method can be used to explore the direct interaction of cells/tissue with medical devices such as metal implants in the future. PMID:28682058

ProMateus—an open research approach to protein-binding sites analysis

PubMed Central

Neuvirth, Hani; Heinemann, Uri; Birnbaum, David; Tishby, Naftali; Schreiber, Gideon

2007-01-01

The development of bioinformatic tools by individual labs results in the abundance of parallel programs for the same task. For example, identification of binding site regions between interacting proteins is done using: ProMate, WHISCY, PPI-Pred, PINUP and others. All servers first identify unique properties of binding sites and then incorporate them into a predictor. Obviously, the resulting prediction would improve if the most suitable parameters from each of those predictors would be incorporated into one server. However, because of the variation in methods and databases, this is currently not feasible. Here, the protein-binding site prediction server is extended into a general protein-binding sites research tool, ProMateus. This web tool, based on ProMate's infrastructure enables the easy exploration and incorporation of new features and databases by the user, providing an evaluation of the benefit of individual features and their combination within a set framework. This transforms the individual research into a community exercise, bringing out the best from all users for optimized predictions. The analysis is demonstrated on a database of protein protein and protein-DNA interactions. This approach is basically different from that used in generating meta-servers. The implications of the open-research approach are discussed. ProMateus is available at http://bip.weizmann.ac.il/promate. PMID:17488838

An analysis of the potential for Glen Canyon Dam releases to inundate archaeological sites in the Grand Canyon, Arizona

USGS Publications Warehouse

Sondossi, Hoda A.; Fairley, Helen C.

2014-01-01

The development of a one-dimensional flow-routing model for the Colorado River between Lees Ferry and Diamond Creek, Arizona in 2008 provided a potentially useful tool for assessing the degree to which varying discharges from Glen Canyon Dam may inundate terrestrial environments and potentially affect resources located within the zone of inundation. Using outputs from the model, a geographic information system analysis was completed to evaluate the degree to which flows from Glen Canyon Dam might inundate archaeological sites located along the Colorado River in the Grand Canyon. The analysis indicates that between 4 and 19 sites could be partially inundated by flows released from Glen Canyon Dam under current (2014) operating guidelines, and as many as 82 archaeological sites may have been inundated to varying degrees by uncontrolled high flows released in June 1983. Additionally, the analysis indicates that more of the sites currently (2014) proposed for active management by the National Park Service are located at low elevations and, therefore, tend to be more susceptible to potential inundation effects than sites not currently (2014) targeted for management actions, although the potential for inundation occurs in both groups of sites. Because of several potential sources of error and uncertainty associated with the model and with limitations of the archaeological data used in this analysis, the results are not unequivocal. These caveats, along with the fact that dam-related impacts can involve more than surface-inundation effects, suggest that the results of this analysis should be used with caution to infer potential effects of Glen Canyon Dam on archaeological sites in the Grand Canyon.

Single-molecule electrocatalysis by single-walled carbon nanotubes.

PubMed

Xu, Weilin; Shen, Hao; Kim, Yoon Ji; Zhou, Xiaochun; Liu, Guokun; Park, Jiwoong; Chen, Peng

2009-12-01

We report a single-molecule fluorescence study of electrocatalysis by single-walled carbon nanotubes (SWNTs) at single-reaction resolution. Applying super-resolution optical imaging, we find that the electrocatalysis occurs at discrete, nanometer-dimension sites on SWNTs. Single-molecule kinetic analysis leads to an electrocatalytic mechanism, allowing quantification of the reactivity and heterogeneity of individual reactive sites. Combined with conductivity measurements, this approach will be powerful to interrogate how the electronic structure of SWNTs affects the electrocatalytic interfacial charge transfer, a process fundamental to photoelectrochemical cells.

In silico analysis of Pycnoporus cinnabarinus laccase active site with toxic industrial dyes.

PubMed

Prasad, Nirmal K; Vindal, Vaibhav; Narayana, Siva Lakshmi; Ramakrishna, V; Kunal, Swaraj Priyaranjan; Srinivas, M

2012-05-01

Laccases belong to multicopper oxidases, a widespread class of enzymes implicated in many oxidative functions in various industrial oxidative processes like production of fine chemicals to bioremediation of contaminated soil and water. In order to understand the mechanisms of substrate binding and interaction between substrates and Pycnoporus cinnabarinus laccase, a homology model was generated. The resulted model was further validated and used for docking studies with toxic industrial dyes- acid blue 74, reactive black 5 and reactive blue 19. Interactions of chemical mediators with the laccase was also examined. The docking analysis showed that the active site always cannot accommodate the dye molecules, due to constricted nature of the active site pocket and steric hindrance of the residues whereas mediators are relatively small and can easily be accommodated into the active site pocket, which, thereafter leads to the productive binding. The binding properties of these compounds along with identification of critical active site residues can be used for further site-directed mutagenesis experiments in order to identify their role in activity and substrate specificity, ultimately leading to improved mutants for degradation of these toxic compounds.

Single-molecule height measurements on microsomal cytochrome P450 in nanometer-scale phospholipid bilayer disks

NASA Astrophysics Data System (ADS)

Bayburt, Timothy H.; Sligar, Stephen G.

2002-05-01

The architecture of membrane proteins in their native environment of the phospholipid bilayer is critical for understanding physiological function, but has been difficult to realize experimentally. In this communication we describe the incorporation of a membrane-anchored protein into a supported phospholipid bilayer. Cytochrome P450 2B4 solubilized and purified from the hepatic endoplasmic reticulum was incorporated into phospholipid bilayer nanostructures and oriented on a surface for visualization by atomic force microscopy. Individual P450 molecules were observed protruding from the bilayer surface. Problems associated with deformation of the protein by the atomic force microscopy probe were avoided by analyzing force-dependent height measurements to quantitate the height of the protein above the bilayer surface. Measurements of the atomic force microscopy cantilever deflection as a function of probe-sample separation reveal that the top of the P450 opposite the N-terminal membrane anchor region sits 3.5 nanometers above the phospholipid-water boundary. Models of the orientation of the enzyme are presented and discussed in relation to membrane interactions and interaction with cytochrome P450 reductase.

Shear-wave velocity and site-amplification factors for 50 Australian sites determined by the spectral analysis of surface waves method

USGS Publications Warehouse

Kayen, Robert E.; Carkin, Bradley A.; Allen, Trevor; Collins, Clive; McPherson, Andrew; Minasian, Diane L.

2015-01-01

One-dimensional shear-wave velocity (VS ) profiles are presented at 50 strong motion sites in New South Wales and Victoria, Australia. The VS profiles are estimated with the spectral analysis of surface waves (SASW) method. The SASW method is a noninvasive method that indirectly estimates the VS at depth from variations in the Rayleigh wave phase velocity at the surface.

Multi-site recording and spectral analysis of spontaneous photon emission from human body.

PubMed

Wijk, Eduard P A Van; Wijk, Roeland Van

2005-04-01

In the past years, research on ultraweak photon emission (UPE) from human body has increased for isolated cells and tissues. However, there are only limited data on UPE from the whole body, in particular from the hands. To describe a protocol for the management of subjects that (1) avoids interference with light-induced longterm delayed luminescence, and (2) includes the time slots for recording photon emission. The protocol was utilised for multi-site recording of 4 subjects at different times of the day and different seasons, and for one subject to complete spectral analysis of emission from different body locations. An especially selected low-noise end-window photomultiplier was utilised for the detection of ultraviolet / visible light (200-650 nm) photon emission. For multi-site recording it was manipulated in three directions in a darkroom with a very low count rate. A series of cut-off filters was used for spectral analysis of UPE. 29 body sites were selected such that the distribution in UPE could be studied as right-left symmetry, dorsal-ventral symmetry, and the ratio between the central body part and extremities. Generally, the fluctuation in photon counts over the body was lower in the morning than in the afternoon. The thorax-abdomen region emitted lowest and most constantly. The upper extremities and the head region emitted most and increasingly over the day. Spectral analysis of low, intermediate and high emission from the superior frontal part of the right leg, the forehead and the palms in the sensitivity range of the photomultiplier showed the major spontaneous emission at 470-570 nm. The central palm area of hand emission showed a larger contribution of the 420-470 nm range in the spectrum of spontaneous emission from the hand in autumn/winter. The spectrum of delayed luminescence from the hand showed major emission in the same range as spontaneous emission. Examples of multi-site UPE recordings and spectral analysis revealed individual patterns

Egypt's Red Sea coast: phylogenetic analysis of cultured microbial consortia in industrialized sites

PubMed Central

Mustafa, Ghada A.; Abd-Elgawad, Amr; Abdel-Haleem, Alyaa M.; Siam, Rania

2014-01-01

The Red Sea possesses a unique geography, and its shores are rich in mangrove, macro-algal and coral reef ecosystems. Various sources of pollution affect Red Sea biota, including microbial life. We assessed the effects of industrialization on microbes along the Egyptian Red Sea coast at eight coastal sites and two lakes. The bacterial communities of sediment samples were analyzed using bacterial 16S rDNA pyrosequencing of V6-V4 hypervariable regions. The taxonomic assignment of 131,402 significant reads to major bacterial taxa revealed five main bacterial phyla dominating the sampled sites: Proteobacteria (68%), Firmicutes (13%), Fusobacteria (12%), Bacteriodetes (6%), and Spirochetes (0.03%). Further analysis revealed distinct bacterial consortia that primarily included (1) marine Vibrio spp.—suggesting a “marine Vibrio phenomenon”; (2) potential human pathogens; and (3) oil-degrading bacteria. We discuss two divergent microbial consortia that were sampled from Solar Lake West near Taba/Eilat and Saline Lake in Ras Muhammad; these consortia contained the highest abundance of human pathogens and no pathogens, respectively. Our results draw attention to the effects of industrialization on the Red Sea and suggest the need for further analysis to overcome the hazardous effects observed at the impacted sites. PMID:25157243

Low pressure hand made PVD system for high crystalline metal thin film preparation in micro-nanometer scale

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

Rosikhin, Ahmad, E-mail: a.rosikhin86@yahoo.co.id; Hidayat, Aulia Fikri; Marimpul, Rinaldo

High crystalline metal thin film preparation in application both for catalyst substrate or electrode in any electronic devices always to be considered in material functional material research and development. As a substrate catalyst, this metal take a role as guidance for material growth in order to resulted in proper surface structure although at the end it will be removed via etching process. Meanwhile as electrodes, it will dragging charges to be collected inside. This brief discussion will elaborate general fundamental principle of physical vapor deposition (PVD) system for metal thin film preparation in micro-nanometer scale. The influence of thermodynamic parametersmore » and metal characteristic such as melting point and particle size will be elucidated. Physical description of deposition process in the chamber can be simplified by schematic evaporation phenomena which is supported by experimental measurement such as SEM and XRD.« less

Using fuzzy logic analysis for siting decisions of infiltration trenches for highway runoff control.

PubMed

Ki, Seo Jin; Ray, Chittaranjan

2014-09-15

Determining optimal locations for best management practices (BMPs), including their field considerations and limitations, plays an important role for effective stormwater management. However, these issues have been often overlooked in modeling studies that focused on downstream water quality benefits. This study illustrates the methodology of locating infiltration trenches at suitable locations from spatial overlay analyses which combine multiple layers that address different aspects of field application into a composite map. Using seven thematic layers for each analysis, fuzzy logic was employed to develop a site suitability map for infiltration trenches, whereas the DRASTIC method was used to produce a groundwater vulnerability map on the island of Oahu, Hawaii, USA. In addition, the analytic hierarchy process (AHP), one of the most popular overlay analyses, was used for comparison to fuzzy logic. The results showed that the AHP and fuzzy logic methods developed significantly different index maps in terms of best locations and suitability scores. Specifically, the AHP method provided a maximum level of site suitability due to its inherent aggregation approach of all input layers in a linear equation. The most eligible areas in locating infiltration trenches were determined from the superposition of the site suitability and groundwater vulnerability maps using the fuzzy AND operator. The resulting map successfully balanced qualification criteria for a low risk of groundwater contamination and the best BMP site selection. The results of the sensitivity analysis showed that the suitability scores were strongly affected by the algorithms embedded in fuzzy logic; therefore, caution is recommended with their use in overlay analysis. Accordingly, this study demonstrates that the fuzzy logic analysis can not only be used to improve spatial decision quality along with other overlay approaches, but also is combined with general water quality models for initial and refined

Climate-driven uncertainties in modeling terrestrial gross primary production: a site level to global-scale analysis.

PubMed

Barman, Rahul; Jain, Atul K; Liang, Miaoling

2014-05-01

We used a land surface model to quantify the causes and extents of biases in terrestrial gross primary production (GPP) due to the use of meteorological reanalysis datasets. We first calibrated the model using meteorology and eddy covariance data from 25 flux tower sites ranging from the tropics to the northern high latitudes and subsequently repeated the site simulations using two reanalysis datasets: NCEP/NCAR and CRUNCEP. The results show that at most sites, the reanalysis-driven GPP bias was significantly positive with respect to the observed meteorology-driven simulations. Notably, the absolute GPP bias was highest at the tropical evergreen tree sites, averaging up to ca. 0.45 kg C m(-2)  yr(-1) across sites (ca. 15% of site level GPP). At the northern mid-/high-latitude broadleaf deciduous and the needleleaf evergreen tree sites, the corresponding annual GPP biases were up to 20%. For the nontree sites, average annual biases of up to ca. 20-30% were simulated within savanna, grassland, and shrubland vegetation types. At the tree sites, the biases in short-wave radiation and humidity strongly influenced the GPP biases, while the nontree sites were more affected by biases in factors controlling water stress (precipitation, humidity, and air temperature). In this study, we also discuss the influence of seasonal patterns of meteorological biases on GPP. Finally, using model simulations for the global land surface, we discuss the potential impacts of site-level reanalysis-driven biases on the global estimates of GPP. In a broader context, our results can have important consequences on other terrestrial ecosystem fluxes (e.g., net primary production, net ecosystem production, energy/water fluxes) and reservoirs (e.g., soil carbon stocks). In a complementary study (Barman et al., ), we extend the present analysis for latent and sensible heat fluxes, thus consistently integrating the analysis of climate-driven uncertainties in carbon, energy, and water fluxes

Analysis Methodology for Optimal Selection of Ground Station Site in Space Missions

NASA Astrophysics Data System (ADS)

Nieves-Chinchilla, J.; Farjas, M.; Martínez, R.

2013-12-01

Optimization of ground station sites is especially important in complex missions that include several small satellites (clusters or constellations) such as the QB50 project, where one ground station would be able to track several spatial vehicles, even simultaneously. In this regard the design of the communication system has to carefully take into account the ground station site and relevant signal phenomena, depending on the frequency band. To propose the optimal location of the ground station, these aspects become even more relevant to establish a trusted communication link due to the ground segment site in urban areas and/or selection of low orbits for the space segment. In addition, updated cartography with high resolution data of the location and its surroundings help to develop recommendations in the design of its location for spatial vehicles tracking and hence to improve effectiveness. The objectives of this analysis methodology are: completion of cartographic information, modelling the obstacles that hinder communication between the ground and space segment and representation in the generated 3D scene of the degree of impairment in the signal/noise of the phenomena that interferes with communication. The integration of new technologies of geographic data capture, such as 3D Laser Scan, determine that increased optimization of the antenna elevation mask, in its AOS and LOS azimuths along the horizon visible, maximizes visibility time with spatial vehicles. Furthermore, from the three-dimensional cloud of points captured, specific information is selected and, using 3D modeling techniques, the 3D scene of the antenna location site and surroundings is generated. The resulting 3D model evidences nearby obstacles related to the cartographic conditions such as mountain formations and buildings, and any additional obstacles that interfere with the operational quality of the antenna (other antennas and electronic devices that emit or receive in the same bandwidth

Control of Pteridium aquilinum: Meta-analysis of a Multi-site Study in the UK

PubMed Central

Stewart, Gavin; Cox, Emma; Le Duc, Mike; Pakeman, Robin; Pullin, Andrew; Marrs, Rob

2008-01-01

Background and Aims A great deal of money is spent controlling invasive weeds as part of international and national policies. It is essential that the funded treatments work across the region in which the policies operate. We argue that experiments across multiple sites are required to validate these programs as results from single sites may be misleading. Here, the control of Pteridium aquilinum (bracken) is used as a test example to address the following four questions. (1) Does the effectiveness of P. aquilinum-control treatments vary across sites? (2) Is the best treatment identified in previous research (cutting twice per year) consistent at all sites, and if not why not? (3) Is treatment performance related to P. aquilinum rhizome mass, litter cover or litter depth at the various sites? (4) Does successful P. aquilinum control influence species richness? Methods Pteridium aquilinum‐control treatments were monitored for 10 years using six replicated experiments and analysed using meta-analysis. Meta-regressions were used to explore heterogeneity between sites. Key Results The effectiveness of treatments varied between sites depending on the measure used to assess P. aquilinum performance. In general, cutting twice per year was the most successful treatment but on some sites other, less expensive treatments were as good. The effectiveness of treatments at different sites was not related to rhizome mass, but the effectiveness of most applied treatments were inversely related to post-control litter. Effective treatment was also associated with high species richness. Conclusions It is concluded that successful development of national weed control programs requires multi-site experimental approaches. Here, meta-analyses demonstrate that variation in effectiveness between sites could be explained in part by pre-specified variables. Reliance on data from a single site for policy formulation is therefore clearly dangerous. PMID:18337356

Probabilistic and Scenario Seismic and Liquefaction Hazard Analysis of the Mississippi Embayment Incorporating Nonlinear Site Effects

NASA Astrophysics Data System (ADS)

Cramer, C. H.; Dhar, M. S.

2017-12-01

The influence of deep sediment deposits of the Mississippi Embayment (ME) on the propagation of seismic waves is poorly understood and remains a major source of uncertainty for site response analysis. Many researchers have studied the effects of these deposits on seismic hazard of the area using available information at the time. In this study, we have used updated and newly available resources for seismic and liquefaction hazard analyses of the ME. We have developed an improved 3D geological model. Additionally, we used surface geological maps from Cupples and Van Arsdale (2013) to prepare liquefaction hazard maps. Both equivalent linear and nonlinear site response codes were used to develop site amplification distributions for use in generating hazard maps. The site amplification distributions are created using the Monte Carlo approach of Cramer et al. (2004, 2006) on a 0.1-degree grid. The 2014 National Seismic Hazard model and attenuation relations (Petersen et al., 2014) are used to prepare seismic hazard maps. Then liquefaction hazard maps are generated using liquefaction probability curves from Holzer (2011) and Cramer et al. (2015). Equivalent linear response (w/ increased precision, restricted nonlinear behavior with depth) shows similar hazard for the ME compared to nonlinear analysis (w/o pore pressure) results. At short periods nonlinear deamplification dominates the hazard, but at long periods resonance amplification dominates. The liquefaction hazard tends to be high in Holocene and late Pleistocene lowland sediments, even with lowered ground water levels, and low in Pleistocene loess of the uplands. Considering pore pressure effects in nonlinear site response analysis at a test site on the lowlands shows amplification of ground motion at short periods. PGA estimates from ME liquefaction and MMI observations are in the 0.25 to 0.4 g range. Our estimated M7.5 PGA hazard within 10 km of the fault can exceed this. Ground motion observations from

Multi-site genetic analysis of diffusion images and voxelwise heritability analysis: A pilot project of the ENIGMA–DTI working group

PubMed Central

Jahanshad, Neda; Kochunov, Peter; Sprooten, Emma; Mandl, René C.; Nichols, Thomas E.; Almassy, Laura; Blangero, John; Brouwer, Rachel M.; Curran, Joanne E.; de Zubicaray, Greig I.; Duggirala, Ravi; Fox, Peter T.; Hong, L. Elliot; Landman, Bennett A.; Martin, Nicholas G.; McMahon, Katie L.; Medland, Sarah E.; Mitchell, Braxton D.; Olvera, Rene L.; Peterson, Charles P.; Starr, John M.; Sussmann, Jessika E.; Toga, Arthur W.; Wardlaw, Joanna M.; Wright, Margaret J.; Hulshoff Pol, Hilleke E.; Bastin, Mark E.; McIntosh, Andrew M.; Deary, Ian J.; Thompson, Paul M.; Glahn, David C.

2013-01-01

The ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Consortium was set up to analyze brain measures and genotypes from multiple sites across the world to improve the power to detect genetic variants that influence the brain. Diffusion tensor imaging (DTI) yields quantitative measures sensitive to brain development and degeneration, and some common genetic variants may be associated with white matter integrity or connectivity. DTI measures, such as the fractional anisotropy (FA) of water diffusion, may be useful for identifying genetic variants that influence brain microstructure. However, genome-wide association studies (GWAS) require large populations to obtain sufficient power to detect and replicate significant effects, motivating a multi-site consortium effort. As part of an ENIGMA–DTI working group, we analyzed high-resolution FA images from multiple imaging sites across North America, Australia, and Europe, to address the challenge of harmonizing imaging data collected at multiple sites. Four hundred images of healthy adults aged 18–85 from four sites were used to create a template and corresponding skeletonized FA image as a common reference space. Using twin and pedigree samples of different ethnicities, we used our common template to evaluate the heritability of tract-derived FA measures. We show that our template is reliable for integrating multiple datasets by combining results through meta-analysis and unifying the data through exploratory mega-analyses. Our results may help prioritize regions of the FA map that are consistently influenced by additive genetic factors for future genetic discovery studies. Protocols and templates are publicly available at (http://enigma.loni.ucla.edu/ongoing/dti-working-group/). PMID:23629049

Three-Dimensional Nanometer Features of Direct Current Electrical Trees in Low-Density Polyethylene.

PubMed

Pallon, Love K H; Nilsson, Fritjof; Yu, Shun; Liu, Dongming; Diaz, Ana; Holler, Mirko; Chen, Xiangrong R; Gubanski, Stanislaw; Hedenqvist, Mikael S; Olsson, Richard T; Gedde, Ulf W

2017-03-08

Electrical trees are one reason for the breakdown of insulating materials in electrical power systems. An understanding of the growth of electrical trees plays a crucial role in the development of reliable high voltage direct current (HVDC) power grid systems with transmission voltages up to 1 MV. A section that contained an electrical tree in low-density polyethylene (LDPE) has been visualized in three dimensions (3D) with a resolution of 92 nm by X-ray ptychographic tomography. The 3D imaging revealed prechannel-formations with a lower density with the width of a couple of hundred nanometers formed around the main branch of the electrical tree. The prechannel structures were partially connected with the main tree via paths through material with a lower density, proving that the tree had grown in a step-by-step manner via the prestep structures formed in front of the main channels. All the prechannel structures had a size well below the limit of the Paschen law and were thus not formed by partial discharges. Instead, it is suggested that the prechannel structures were formed by electro-mechanical stress and impact ionization, where the former was confirmed by simulations to be a potential explanation with electro-mechanical stress tensors being almost of the same order of magnitude as the short-term modulus of low-density polyethylene.

GIS least-cost analysis approach for siting gas pipeline ROWs

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

Sydelko, P.J.; Wilkey, P.L.

1994-09-01

Geographic-information-system applications for the siting and monitoring of gas pipeline rights-of-way (ROWS) were developed for areas near Rio Vista, California. The data layers developed for this project represent geographic features, such as landcover, elevation, aspect, slope, soils, hydrography, transportation corridors, endangered species habitats, wetlands, and public line surveys. A geographic information system was used to develop and store spatial data from several sources; to manipulate spatial data to evaluate environmental and engineering issues associated with the siting, permitting, construction, maintenance, and monitoring of gas-pipeline ROWS; and to graphically display analysis results. Examples of these applications include (1) determination of environmentallymore » sensitive areas, such as endangered species habitat, wetlands, and areas of highly erosive soils; (2) evaluation of engineering constraints, including shallow depth to bedrock, major hydrographic features, and shallow water table; (3) classification of satellite imagery for landuse/landcover that will affect ROWS; and (4) identification of alternative ROW corridors that avoid environmentally sensitive areas or areas with severe engineering constraints.« less

Coastal flooding as a parameter in multi-criteria analysis for industrial site selection

NASA Astrophysics Data System (ADS)

Christina, C.; Memos, C.; Diakoulaki, D.

2014-12-01

Natural hazards can trigger major industrial accidents, which apart from affecting industrial installations may cause a series of accidents with serious impacts on human health and the environment far beyond the site boundary. Such accidents, also called Na-Tech (natural - technical) accidents, deserve particular attention since they can cause release of hazardous substances possibly resulting in severe environmental pollution, explosions and/or fires. There are different kinds of natural events or, in general terms, of natural causes of industrial accidents, such as landslides, hurricanes, high winds, tsunamis, lightning, cold/hot temperature, floods, heavy rains etc that have caused accidents. The scope of this paper is to examine the coastal flooding as a parameter in causing an industrial accident, such as the nuclear disaster in Fukushima, Japan, and the critical role of this parameter in industrial site selection. Land use planning is a complex procedure that requires multi-criteria decision analysis involving economic, environmental and social parameters. In this context the parameter of a natural hazard occurrence, such as coastal flooding, for industrial site selection should be set by the decision makers. In this paper it is evaluated the influence that has in the outcome of a multi-criteria decision analysis for industrial spatial planning the parameter of an accident risk triggered by coastal flooding. The latter is analyzed in the context of both sea-and-inland induced flooding.

Radioactive dispersion analysis for hypothetical nuclear power plant (NPP) candidate site in Perak state, Malaysia

NASA Astrophysics Data System (ADS)

Shamsuddin, Shazmeen Daniar; Basri, Nor Afifah; Omar, Nurlyana; Koh, Meng-Hock; Ramli, Ahmad Termizi; Saridan Wan Hassan, Wan Muhamad

2017-10-01

Malaysia is planning to build a nuclear power plant (NPP) by 2030 to diversify the national electricity supply and resources. Selection of an NPP site must consider various factors, especially nuclear safety consideration to fulfil the nuclear safety objectives. Environmental Risk Assessment Analysis is a part of safety requirements by the International Atomic Energy Agency (IAEA) prior to the NPP commissioning process. Risk Assessments Analysis (RIA) is compulsory for the NPP site evaluation. One of RIA methods are Radioactive Dispersion Analysis using probabilistic risk analysis software. It is also important to perform studies to estimate the impact to the neighbouring population in the case of a nuclear accident at the power plant. In the present work, aimed to study the impact of a hypothetical nuclear accident by simulating the dispersion pattern of radionuclides originated from a candidate site at Manjung, Perak. The work has been performed using the HotSpot Health Physics codes. Two types of radionuclides have been considered namely 137Cs and 131I. In calculations, the initial concentration of radioactive materials of Fukushima Daiichi accident data are used which are 2.06 x 1016 Bq and 1.68 x 1017 Bq respectively for the two radionuclides. The result shows that the dispersion distance obtained from both software are not the same. It shows that 137Cs and 131I can be dispersed as far as 16 km and 80 km away from the site during radiological accident respectively, reaching major towns in Perak. Using HOTSPOT, the estimated total effective dose equivalent (TEDE) for 137Cs and 131I at major towns in Perak such as Lumut and Sitiawan are 1.2 mSv and 9.9 mSv. As for Taiping, Ipoh, Kampar, and Teluk Intan the estimated TEDE is around 0.2 mSv and 1.6 mSv respectively. In conclusion, the dispersion can reach as far as 80 km from the site. However, estimated annual effective dose is not more than 1 mSv limit, which is considered acceptable in the point of view of

40 CFR 1400.8 - Access to off-site consequence analysis information by Federal government officials.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENVIRONMENTAL PROTECTION AGENCY AND DEPARTMENT OF JUSTICE ACCIDENTAL RELEASE PREVENTION REQUIREMENTS; RISK MANAGEMENT PROGRAMS UNDER THE CLEAN AIR ACT SECTION 112(r)(7); DISTRIBUTION OF OFF-SITE CONSEQUENCE ANALYSIS...

Laser induced phosphorescence uranium analysis

DOEpatents

Bushaw, B.A.

1983-06-10

A method is described for measuring the uranium content of aqueous solutions wherein a uranyl phosphate complex is irradiated with a 5 nanosecond pulse of 425 nanometer laser light and resultant 520 nanometer emissions are observed for a period of 50 to 400 microseconds after the pulse. Plotting the natural logarithm of emission intensity as a function of time yields an intercept value which is proportional to uranium concentration.

Laser induced phosphorescence uranium analysis

DOEpatents

Bushaw, Bruce A.

1986-01-01

A method is described for measuring the uranium content of aqueous solutions wherein a uranyl phosphate complex is irradiated with a 5 nanosecond pulse of 425 nanometer laser light and resultant 520 nanometer emissions are observed for a period of 50 to 400 microseconds after the pulse. Plotting the natural logarithm of emission intensity as a function of time yields an intercept value which is proportional to uranium concentration.

Volumetric Stress-Strain Analysis of Optohydrodynamically Suspended Biological Cells

PubMed Central

Liang, Yu; Saha, Asit K.

2011-01-01

Ongoing investigations are exploring the biomechanical properties of isolated and suspended biological cells in pursuit of understanding single-cell mechanobiology. An optical tweezer with minimal applied laser power has positioned biologic cells at the geometric center of a microfluidic cross-junction, creating a novel optohydrodynamic trap. The resulting fluid flow environment facilitates unique multiaxial loading of single cells with site-specific normal and shear stresses resulting in a physical albeit extensional state. A recent two-dimensional analysis has explored the cytoskeletal strain response due to these fluid-induced stresses [Wilson and Kohles, 2010, “Two-Dimensional Modeling of Nanomechanical Stresses-Strains in Healthy and Diseased Single-Cells During Microfluidic Manipulation,” J Nanotechnol Eng Med, 1(2), p. 021005]. Results described a microfluidic environment having controlled nanometer and piconewton resolution. In this present study, computational fluid dynamics combined with multiphysics modeling has further characterized the applied fluid stress environment and the solid cellular strain response in three dimensions to accompany experimental cell stimulation. A volumetric stress-strain analysis was applied to representative living cell biomechanical data. The presented normal and shear stress surface maps will guide future microfluidic experiments as well as provide a framework for characterizing cytoskeletal structure influencing the stress to strain response. PMID:21186894

Crescent Evaluation : appendix A : on-site analysis of HELP technologies and operations evaluation report

DOT National Transportation Integrated Search

1994-02-01

This report describes the data collection procedures, the data analysis methods, and the results gained from the on-site evaluations. The content of the report is as follows: Chapter 2 - State Profiles. This chapter includes descriptions of the organ...

Ab initio calculation of the deprotonation constants of an atomistically defined nanometer-sized, aluminium hydroxide oligomer

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

Wander, Matthew C. F.; Shuford, Kevin L.; Rustad, James R.

Aluminium possesses significant and diverse chemistry. Numerous compounds have been defined, and the elucidation of their chemistry is of significant geochemical interest. In this paper, a brucite-like, eight-aluminium aqueous cluster is modelled with density functional theory to identify its primary site of deprotonation and the associated pK(a) constant using both explicit (a full first solvent shell) and implicit solvent. Two methods for calculating the pK(a) are compared. We found that a bond density approach is better than a direct energy calculation for ions with large charge and high symmetry. The terminal aluminium atoms have equatorial ligated waters that in solventmore » have one long O-H bond. This site is more reactive than any of the other protons on the particle. Insights into the experimental crystal structure and Bader's Atoms in Molecules density analysis are presented as routes to reduce the computational time required for the identification of protonation sites.« less

Improving safety on rural local and tribal roads site safety analysis - user guide #1.

DOT National Transportation Integrated Search

2014-08-01

This User Guide presents an example of how rural local and Tribal practitioners can study conditions at a preselected site. It demonstrates the step-by-step safety analysis process presented in Improving Safety on Rural Local and Tribal Roads Saf...

Analysis and interpretation of geophysical surveys in archaeological sites employing different integrated approach.

NASA Astrophysics Data System (ADS)

Piro, Salvatore; Papale, Enrico; Kucukdemirci, Melda; Zamuner, Daniela

2017-04-01

dating from the third century B.C. The second site is always in suburban area and is part of the ancient acropolis Etruscan town of Cerveteri (central Italy). The third site is part of Aizanoi archaeological park (Cavdarhisar, Kutahya, Turkey). To have a better understanding of the subsurface, we performed a different integrated approaches of these data, which consists in fusing the data from all the employed methods, to have a complete visualization of the investigated area. For the processing we have used the following techniques: graphical integration (overlay and RGB colour composite), discrete data analysis (binary data analysis and cluster analysis) and continuous data analysis (data sum, product, max, min and PCA). Ernenwein, E.G. 2009. Integration of multidimensional archaeogeophysical data using supervised and unsupervised classification. Near surface geophysics. Vol 7: 147-158. DOI:10.3997/1873-0604.2009004 Kucukdemirci,M., Piro.S.,Baydemir,N.,Ozer.,E. Zamuner.,D. 2015. Mathematical and Statistical Integration approach on archaeological prospection data,case studies from Aizanoi-Turkey. 43rd Computer Applications and Quantitative Methods in Archaeology, Siena. Kvamme,K.,2007. Integrating Multiple Geophysical Datasets, Remote Sensing in archaeology, Springer,Boston. Piro,S.,Mauriello.,P. and Cammarano.,F.2000. Quantitative Integration of Geophysical methods for Archaeological Prospection. Archaeological prospection 7(4): 203-213. Piro S., Papale E., Zamuner D., 2016. Different integrated geophysical approaches to investigate archaeological sites in urban and suburban area. Geophysical Research Abstracts Vol. 18, EGU2016.

Analysis of functional importance of binding sites in the Drosophila gap gene network model.

PubMed

Kozlov, Konstantin; Gursky, Vitaly V; Kulakovskiy, Ivan V; Dymova, Arina; Samsonova, Maria

2015-01-01

The statistical thermodynamics based approach provides a promising framework for construction of the genotype-phenotype map in many biological systems. Among important aspects of a good model connecting the DNA sequence information with that of a molecular phenotype (gene expression) is the selection of regulatory interactions and relevant transcription factor bindings sites. As the model may predict different levels of the functional importance of specific binding sites in different genomic and regulatory contexts, it is essential to formulate and study such models under different modeling assumptions. We elaborate a two-layer model for the Drosophila gap gene network and include in the model a combined set of transcription factor binding sites and concentration dependent regulatory interaction between gap genes hunchback and Kruppel. We show that the new variants of the model are more consistent in terms of gene expression predictions for various genetic constructs in comparison to previous work. We quantify the functional importance of binding sites by calculating their impact on gene expression in the model and calculate how these impacts correlate across all sites under different modeling assumptions. The assumption about the dual interaction between hb and Kr leads to the most consistent modeling results, but, on the other hand, may obscure existence of indirect interactions between binding sites in regulatory regions of distinct genes. The analysis confirms the previously formulated regulation concept of many weak binding sites working in concert. The model predicts a more or less uniform distribution of functionally important binding sites over the sets of experimentally characterized regulatory modules and other open chromatin domains.

Inherent size effects on XANES of nanometer metal clusters: Size-selected platinum clusters on silica

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

Dai, Yang; Gorey, Timothy J.; Anderson, Scott L.

2016-12-12

X-ray absorption near-edge structure (XANES) is commonly used to probe the oxidation state of metal-containing nanomaterials, however, as the particle size in the material drops below a few nanometers, it becomes important to consider inherent size effects on the electronic structure of the materials. In this paper, we analyze a series of size-selected Pt n/SiO 2 samples, using X-ray photoelectron spectroscopy (XPS), low energy ion scattering, grazing-incidence small angle X-ray scattering, and XANES. The oxidation state and morphology are characterized both as-deposited in UHV, and after air/O 2 exposure and annealing in H 2. Here, the clusters are found tomore » be stable during deposition and upon air exposure, but sinter if heated above ~150 °C. XANES shows shifts in the Pt L 3 edge, relative to bulk Pt, that increase with decreasing cluster size, and the cluster samples show high white line intensity. Reference to bulk standards would suggest that the clusters are oxidized, however, XPS shows that they are not. Instead, the XANES effects are attributable to development of a band gap and localization of empty state wavefunctions in small clusters.« less

Microstructural characterization and strengthening behavior of nanometer sized carbides in Ti–Mo microalloyed steels during continuous cooling process

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

Chen, Chih-Yuan, E-mail: chen6563@gmail.com; Department of Materials Science and Engineering, National Taiwan University, Taipei 10617, Taiwan; Yang, Jer-Ren, E-mail: jryang@ntu.edu.tw

Nanometer-sized carbides that precipitated in a Ti–Mo bearing steel after interrupted continuous cooling in a temperature range of 620–700 °C with or without hot deformation were investigated by field-emission-gun transmission electron microscopy. The nanometer-sized carbides were identified as randomly homogeneous precipitation carbides and interphase precipitation carbides coexisting in the ferrite matrix. It is found that this dual precipitation morphology of carbides in the steel leads to the non-uniform mechanical properties of individual ferrite grains. Vickers hardness data mainly revealed that, in the specimens cooled at a rate of 0.5 °C/s without hot deformation, the range of Vickers hardness distribution wasmore » 230–340 HV 0.1 when cooling was interrupted at 680 °C, and 220–360 HV 0.1 when cooling was interrupted at 650 °C. For the specimens cooled at a rate of 0.5 °C/s with hot deformation, the range of Vickers hardness distribution was 290–360 HV 0.1 when cooling was interrupted at 680 °C, and 280–340 HV 0.1 when cooling was interrupted at 650 °C. Therefore, a narrower range of hardness distribution occurred in the specimens that underwent hot deformation and were then cooled with a lower interrupted cooling temperature. The uniform precipitation status in each ferrite grain can lead to ferrite grains with a narrower Vickers hardness distribution. On the other hand, interrupted cooling produced a maximum Vickers hardness of 320–330 HV 0.1 for the hot deformed specimens and 290–310 HV 0.1 for the non-deformed specimens with cooling interrupted in the temperature range of 660–670 °C. The maximum Vickers hardness obtained in such a temperature range can be ascribed to the full precipitation of the microalloying elements in the supersaturated ferrite matrix with a tiny size (~ 4–7 nm). - Highlight: • The interrupted continuous cooling temperatures were 620 °C to 700 °C. • Precipitation carbides with dual dispersed

Chemical Analysis of the Moon at the Surveyor VII Landing Site: Preliminary Results.

PubMed

Turkevich, A L; Franzgrote, E J; Patterson, J H

1968-10-04

The alpha-scattering experiment aboard Surveyor VII has provided a chemical analysis of the moon in the area of the crater Tycho. The preliminary results indicate a chemical composition similar to that already found at two mare sites, but with a lower concentration of elements of the iron group (titanium through copper).

ON-SITE MERCURY ANALYSIS OF SOIL AT HAZARDOUS WASTE SITES BY IMMUNOASSAY AND ASV

EPA Science Inventory

Two field methods for Hg, immunoassay and anodic stripping voltammetry (ASV), that can provide onsite results for quick decisions at hazardous waste sites were evaluated. Each method was applied to samples from two Superfund sites that contain high levels of Hg; Sulphur Bank Me...

Study of first electronic transition and hydrogen bonding state of ultra-thin water layer of nanometer thickness on an α-alumina surface by far-ultraviolet spectroscopy

NASA Astrophysics Data System (ADS)

Goto, Takeyoshi; Kinugasa, Tomoya

2018-05-01

The first electronic transition (A˜ ← X˜) and the hydrogen bonding state of an ultra-thin water layer of nanometer thickness between two α-alumina surfaces (0.5-20 nm) were studied using far-ultraviolet (FUV) spectroscopy in the wavelength range 140-180 nm. The ultra-thin water layer of nanometer thickness was prepared by squeezing a water droplet ( 1 μL) between a highly polished α-alumina prism and an α-alumina plate using a high pressure clamp ( 4.7 MPa), and the FUV spectra of the water layer at different thicknesses were measured using the attenuated total reflection method. As the water layer became thinner, the A˜ ← X˜ bands were gradually shifted to higher or lower energy relative to that of bulk water; at thicknesses smaller than 4 nm, these shifts were substantial (0.1-0.2 eV) in either case. The FUV spectra of the water layer with thickness < 4 nm indicate the formation of structured ice-like hydrogen bond (H-bond) layers for the higher energy shifts or the formation of slightly weaker H-bond layers as compared to those in the bulk liquid state for lower energy shifts. In either case, the H-bond structure of bulk liquid water is nearly lost at thicknesses below 4 nm, because of steric hydration forces between the α-alumina surfaces.

Photocatalysis effect of nanometer TiO2 and TiO2-coated ceramic plate on Hepatitis B virus.

PubMed

Zan, Ling; Fa, Wenjun; Peng, Tianyou; Gong, Zhen-Kui

2007-02-01

The photocatalysis effect of nanometer TiO2 particles and TiO2-coated ceramic plate on Hepatitis B virus surface antigen (HBsAg) was investigated. The ELISA (enzyme-linked immunosorbent assay) standard method was used to assess the efficiency of TiO2 material to destroy the HBsAg. The research has shown that the suspension of TiO2 (0.5g/L) can destroy most of the HBsAg under the irradiation of mercury lamp, with the light intensity of 0.6mW/cm(2) at 365nm wavelength, or under the sunlight irradiation for a few hours. TiO2-coated ceramic plates can also destroy the HBsAg under the irradiation of mercury lamp, with the light intensity of 0.05mW/cm(2) at 365nm wavelength or under the room daylight for a few hours.

Quantum spill-out in few-nanometer metal gaps: Effect on gap plasmons and reflectance from ultrasharp groove arrays

NASA Astrophysics Data System (ADS)

Skjølstrup, Enok J. H.; Søndergaard, Thomas; Pedersen, Thomas G.

2018-03-01

Plasmons in ultranarrow metal gaps are highly sensitive to the electron density profile at the metal surfaces. Using a quantum mechanical approach and assuming local response, we study the effects of electron spill-out on gap plasmons and reflectance from ultrasharp metal grooves. We demonstrate that the mode index of ultranarrow gap plasmons converges to the bulk refractive index in the limit of vanishing gap and, thereby, rectify the unphysical divergence found in classical models. Surprisingly, spill-out also significantly increases the plasmonic absorption for few-nanometer gaps and lowers the reflectance from arrays of ultrasharp metal grooves. These findings are explained in terms of enhanced gap plasmon absorption taking place inside the gap 1-2 Å from the walls and delocalization near the groove bottom. Reflectance calculations taking spill-out into account are shown to be in much better agreement with measurements compared with classical models.

Mechanical design of multiple zone plates precision alignment apparatus for hard X-ray focusing in twenty-nanometer scale

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

Shu, Deming; Liu, Jie; Gleber, Sophie C.

An enhanced mechanical design of multiple zone plates precision alignment apparatus for hard x-ray focusing in a twenty-nanometer scale is provided. The precision alignment apparatus includes a zone plate alignment base frame; a plurality of zone plates; and a plurality of zone plate holders, each said zone plate holder for mounting and aligning a respective zone plate for hard x-ray focusing. At least one respective positioning stage drives and positions each respective zone plate holder. Each respective positioning stage is mounted on the zone plate alignment base frame. A respective linkage component connects each respective positioning stage and the respectivemore » zone plate holder. The zone plate alignment base frame, each zone plate holder and each linkage component is formed of a selected material for providing thermal expansion stability and positioning stability for the precision alignment apparatus.« less

Highly efficient phosphorescent organic light-emitting diode with a nanometer-thick Ni silicide/polycrystalline p-Si composite anode.

PubMed

Li, Y Z; Wang, Z L; Luo, H; Wang, Y Z; Xu, W J; Ran, G Z; Qin, G G; Zhao, W Q; Liu, H

2010-07-19

A phosphorescent organic light-emitting diode (PhOLED) with a nanometer-thick (approximately 10 nm) Ni silicide/ polycrystalline p-Si composite anode is reported. The structure of the PhOLED is Al mirror/ glass substrate / Si isolation layer / Ni silicide / polycrystalline p-Si/ V(2)O(5)/ NPB/ CBP: (ppy)(2)Ir(acac)/ Bphen/ Bphen: Cs(2)CO(3)/ Sm/ Au/ BCP. In the composite anode, the Ni-induced polycrystalline p-Si layer injects holes into the V(2)O(5)/ NPB, and the Ni silicide layer reduces the sheet resistance of the composite anode and thus the series resistance of the PhOLED. By adopting various measures for specially optimizing the thickness of the Ni layer, which induces Si crystallization and forms a Ni silicide layer of appropriate thickness, the highest external quantum efficiency and power conversion efficiency have been raised to 26% and 11%, respectively.

Urgent and Elective Robotic Single-Site Cholecystectomy: Analysis and Learning Curve of 150 Consecutive Cases.

PubMed

Kubat, Eric; Hansen, Nathan; Nguyen, Huy; Wren, Sherry M; Eisenberg, Dan

2016-03-01

The use of robotic single-site cholecystectomy has increased exponentially. There are few reports describing the safety, efficacy, and operative learning curve of robotic single-site cholecystectomy either in the community setting or with nonelective surgery. We performed a retrospective review of a prospective database of our initial experience with robotic single-site cholecystectomy. Demographics and perioperative outcomes were evaluated for both urgent and elective cholecystectomy. Cumulative sum analysis was performed to determine the surgeon's learning curve. One hundred fifty patients underwent robotic single-site cholecystectomy. Seventy-four (49.3%) patients underwent urgent robotic single-site cholecystectomy, and 76 (50.7%) underwent elective robotic single-site cholecystectomy. Mean total operative time for robotic single-site cholecystectomy was 83.3 ± 2.7 minutes. Mean operative time for the urgent cohort was significantly longer than for the elective cohort (95.0 ± 4.4 versus 71.9 ± 2.6 minutes; P < .001). There was one conversion in the urgent cohort and none in the elective cohort. There was one bile duct injury (0.7%) in the urgent cohort. Perioperative complications occurred in 8.7% of patients, and most consisted of superficial surgical-site infections. There were no incisional hernias detected. The surgeon's learning curve, inclusive of urgent and elective cases, was 48 operations. Robotic single-site cholecystectomy can be performed safely and effectively in both elective and urgent cholecystectomy with a reasonable learning curve and acceptable perioperative outcomes.

Master Plans for Park Sites.

ERIC Educational Resources Information Center

Van Meter, Jerry R.

This booklet is a general guide to park site planning. The four basic steps involved in developing a park site are a) determination of the uses of the site, b) analysis of the site potential for these uses, c) identification of the functional relationship among the uses, and d) coordination of the uses to the park sites. Uses of park sites are…

Application of microtremor horizontal-to-vertical spectral ratio (MHVSR) analysis for site characterization: State of the art

USGS Publications Warehouse

Molnar, S.; Cassidy, J. F.; Castellaro, S.; Cornou, C.; Crow, H.; Hunter, J. A.; Matsushima, S.; Sanchez-Sesma, F. J.; Yong, Alan

2018-01-01

Nakamura (Q Rep Railway Tech Res Inst 30:25–33, 1989) popularized the application of the horizontal-to-vertical spectral ratio (HVSR) analysis of microtremor (seismic noise or ambient vibration) recordings to estimate the predominant frequency and amplification factor of earthquake shaking. During the following quarter century, popularity in the microtremor HVSR (MHVSR) method grew; studies have verified the stability of a site’s MHVSR response over time and validated the MHVSR response with that of earthquake HVSR response. Today, MHVSR analysis is a popular reconnaissance tool used worldwide for seismic microzonation and earthquake site characterization in numerous regions, specifically, in the mapping of site period or fundamental frequency and inverted for shear-wave velocity depth profiles, respectively. However, the ubiquity of MHVSR analysis is predominantly a consequence of its ease in application rather than our full understanding of its theory. We present the state of the art in MHVSR analyses in terms of the development of its theoretical basis, current state of practice, and we comment on its future for applications in earthquake site characterization.

Site-specific seismic probabilistic tsunami hazard analysis: performances and potential applications

NASA Astrophysics Data System (ADS)

Tonini, Roberto; Volpe, Manuela; Lorito, Stefano; Selva, Jacopo; Orefice, Simone; Graziani, Laura; Brizuela, Beatriz; Smedile, Alessandra; Romano, Fabrizio; De Martini, Paolo Marco; Maramai, Alessandra; Piatanesi, Alessio; Pantosti, Daniela

2017-04-01

Seismic Probabilistic Tsunami Hazard Analysis (SPTHA) provides probabilities to exceed different thresholds of tsunami hazard intensity, at a specific site or region and in a given time span, for tsunamis caused by seismic sources. Results obtained by SPTHA (i.e., probabilistic hazard curves and inundation maps) represent a very important input to risk analyses and land use planning. However, the large variability of source parameters implies the definition of a huge number of potential tsunami scenarios, whose omission could lead to a biased analysis. Moreover, tsunami propagation from source to target requires the use of very expensive numerical simulations. At regional scale, the computational cost can be reduced using assumptions on the tsunami modeling (i.e., neglecting non-linear effects, using coarse topo-bathymetric meshes, empirically extrapolating maximum wave heights on the coast). On the other hand, moving to local scale, a much higher resolution is required and such assumptions drop out, since detailed inundation maps require significantly greater computational resources. In this work we apply a multi-step method to perform a site-specific SPTHA which can be summarized in the following steps: i) to perform a regional hazard assessment to account for both the aleatory and epistemic uncertainties of the seismic source, by combining the use of an event tree and an ensemble modeling technique; ii) to apply a filtering procedure which use a cluster analysis to define a significantly reduced number of representative scenarios contributing to the hazard of a specific target site; iii) to perform high resolution numerical simulations only for these representative scenarios and for a subset of near field sources placed in very shallow waters and/or whose coseismic displacements induce ground uplift or subsidence at the target. The method is applied to three target areas in the Mediterranean located around the cities of Milazzo (Italy), Thessaloniki (Greece) and

Site-wide seismic risk model for Savannah River Site nuclear facilities

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

Eide, S.A.; Shay, R.S.; Durant, W.S.

1993-09-01

The 200,000 acre Savannah River Site (SRS) has nearly 30 nuclear facilities spread throughout the site. The safety of each facility has been established in facility-specific safety analysis reports (SARs). Each SAR contains an analysis of risk from seismic events to both on-site workers and the off-site population. Both radiological and chemical releases are considered, and air and water pathways are modeled. Risks to the general public are generally characterized by evaluating exposure to the maximally exposed individual located at the SRS boundary and to the off-site population located within 50 miles. Although the SARs are appropriate methods for studyingmore » individual facility risks, there is a class of accident initiators that can simultaneously affect several of all of the facilities, Examples include seismic events, strong winds or tornados, floods, and loss of off-site electrical power. Overall risk to the off-site population from such initiators is not covered by the individual SARs. In such cases multiple facility radionuclide or chemical releases could occur, and off-site exposure would be greater than that indicated in a single facility SAR. As a step towards an overall site-wide risk model that adequately addresses multiple facility releases, a site-wide seismic model for determining off-site risk has been developed for nuclear facilities at the SRS. Risk from seismic events up to the design basis earthquake (DBE) of 0.2 g (frequency of 2.0E-4/yr) is covered by the model. Present plans include expanding the scope of the model to include other types of initiators that can simultaneously affect multiple facilities.« less

Site Suitability Analysis for Beekeeping via Analythical Hyrearchy Process, Konya Example

NASA Astrophysics Data System (ADS)

Sarı, F.; Ceylan, D. A.

2017-11-01

Over the past decade, the importance of the beekeeping activities has been emphasized in the field of biodiversity, ecosystems, agriculture and human health. Thus, efficient management and deciding correct beekeeping activities seems essential to maintain and improve productivity and efficiency. Due to this importance, considering the economic contributions to the rural area, the need for suitability analysis concept has been revealed. At this point, Multi Criteria Decision Analysis (MCDA) and Geographical Information Systems (GIS) integration provides efficient solutions to the complex structure of decision- making process for beekeeping activities. In this study, site suitability analysis via Analytical Hierarchy Process (AHP) was carried out for Konya city in Turkey. Slope, elevation, aspect, distance to water resources, roads and settlements, precipitation and flora criteria are included to determine suitability. The requirements, expectations and limitations of beekeeping activities are specified with the participation of experts and stakeholders. The final suitability map were validated with existing 117 beekeeping locations and Turkish Statistical Institute 2016 beekeeping statistics for Konya province.

Nanometer-sized extracellular matrix coating on polymer-based scaffold for tissue engineering applications.

PubMed

Uchida, Noriyuki; Sivaraman, Srikanth; Amoroso, Nicholas J; Wagner, William R; Nishiguchi, Akihiro; Matsusaki, Michiya; Akashi, Mitsuru; Nagatomi, Jiro

2016-01-01

Surface modification can play a crucial role in enhancing cell adhesion to synthetic polymer-based scaffolds in tissue engineering applications. Here, we report a novel approach for layer-by-layer (LbL) fabrication of nanometer-size fibronectin and gelatin (FN-G) layers on electrospun fibrous poly(carbonate urethane)urea (PCUU) scaffolds. Alternate immersions into the solutions of fibronectin and gelatin provided thickness-controlled FN-G nano-layers (PCUU(FN-G) ) which maintained the scaffold's 3D structure and width of fibrous bundle of PCUU as evidenced by scanning electron miscroscopy. The PCUU(FN-G) scaffold improved cell adhesion and proliferation of bladder smooth muscles (BSMCs) when compared to uncoated PCUU. The high affinity of PCUU(FN-G) for cells was further demonstrated by migration of adherent BSMCs from culture plates to the scaffold. Moreover, the culture of UROtsa cells, human urothelium-derived cell line, on PCUU(FN-G) resulted in an 11-15 μm thick multilayered cell structure with cell-to-cell contacts although many UROtsa cells died without forming cell connections on PCUU. Together these results indicate that this approach will aid in advancing the technology for engineering bladder tissues in vitro. Because FN-G nano-layers formation is based on nonspecific physical adsorption of fibronectin onto polymer and its subsequent interactions with gelatin, this technique may be applicable to other polymer-based scaffold systems for various tissue engineering/regenerative medicine applications. © 2015 Wiley Periodicals, Inc.

Toxicological effects of nanometer titanium dioxide (nano-TiO2) on Chlamydomonas reinhardtii.

PubMed

Chen, Lanzhou; Zhou, Lina; Liu, Yongding; Deng, Songqiang; Wu, Hao; Wang, Gaohong

2012-10-01

The toxicological effects of nanometer titanium dioxide (nano-TiO2) on a unicellular green alga Chlamydomonas reinhardtii were assessed by investigating the changes of the physiology and cyto-ultrastructure of this species under treatment. We found that nano-TiO2 inhibited photosynthetic efficiency and cell growth, but the content of chlorophyll a content in algae did not change, while carotenoid and chlorophyll b contents increased. Malondialdehyde (MDA) content reached maximum values after 8h exposure and then decreased to a moderately low level at 72 h. Electron microscopy images indicated that as concentrations of nano-TiO2 increased, a large number of C. reinhardtii cells were noted to be damaged: the number of chloroplasts declined, various other organelles were degraded, plasmolysis occurred, and TiO2 nanoparticles were found to be located inside cell wall and membrane. It was also noted that cell surface was surrounded by TiO2 particles, which could present an obstacle to the exchange of substances between the cell and its surrounding environment. To sum up, the effect of nano-TiO2 on C. reinhardtii included cell surface aggregation, photosynthesis inhibition, lipid peroxidation and new protein synthesis, while the response of C. reinhardtii to nano-TiO2 was a rapid process which occurs during 24 h after exposing and may relate to physiological stress system to mitigate damage. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

Colorimetric monitoring of nanometer distance changes in DNA-templated plasmon rulers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lermusiaux, Laurent; Bidault, Sebastien

2016-03-01

The nanometer-scale sensitivity of plasmon coupling allows the translation of minute morphological changes in nanostructures into macroscopic optical signals. In particular, single nanostructure scattering spectroscopy provides a direct estimation of interparticle distances in gold nanoparticle (AuNP) dimers linked by a short DNA double-strand [M. P. Busson et al, Nano Lett. 11, 5060 (2011)]. We demonstrate here that this spectroscopic information can be inferred from simple widefield measurements on a calibrated color camera [L. Lermusiaux et al, ACS Nano 9, 978 (2015)]. This allows us to analyze the influence of electrostatic and steric interparticle interactions on the morphology of DNA-templated AuNP groupings. Furthermore, polarization-resolved measurements on a color CCD provide a parallel imaging of AuNP dimer orientations. We apply this spectroscopic characterization to identify dimers featuring two different conformations of the same DNA template. In practice, the biomolecular scaffold contains a hairpin-loop that opens after hybridization to a specific DNA sequence and increases the interparticle distance [L. Lermusiaux et al, ACS Nano 6, 10992 (2012)]. These results open exciting perspectives for the parallel sensing of single specific DNA strands using plasmon rulers. We discuss the limits of this approach in terms of the physicochemical stability and reactivity of these nanostructures and demonstrate the importance of engineering the AuNP surface chemistry, in particular using amphiphilic ligands [L. Lermusiaux and S. Bidault, Small (2015), in press].

An analysis of deer and elk-vehicle collision sites along state highways in Washington State

DOT National Transportation Integrated Search

2008-05-20

Approximately 3,000 deer and 85 elk carcasses are removed by WSDOT personnel from Washington : state highways annually. The report provides an analysis of temporal and spatial relationships : associated with carcass removal sites. Models were develop...

Outcomes of nonemergent percutaneous coronary intervention with and without on-site surgical backup: a meta-analysis.

PubMed

Singh, Param Puneet; Singh, Mukesh; Bedi, Updesh Singh; Adigopula, Sasikanth; Singh, Sarabjeet; Kodumuri, Vamsi; Molnar, Janos; Ahmed, Aziz; Arora, Rohit; Khosla, Sandeep

2011-01-01

Despite major advances in percutaneous coronary intervention (PCI) techniques, the current guidelines recommend against elective PCI at hospitals without on-site cardiac surgery backup. Nonetheless, an increasing number of hospitals without on-site cardiac surgery in the United States have developed programs for elective PCI. Studies evaluating outcome in this setting have yielded mixed results, leaving the question unanswered. Hence, a meta-analysis comparing outcomes of nonemergent PCI in hospitals with and without on-site surgical backup was performed. A systematic review of literature identified four studies involving 6817 patients. Three clinical end points were extracted from each study and included in-hospital death, myocardial infarction, and the need for emergency coronary artery bypass grafting. The studies were homogenous for each outcome studied. Therefore, the combined relative risks (RRs) across all the studies and the 95% confidence intervals (CIs) were computed using the Mantel-Haenszel fixed-effect model. A two-sided alpha error less than 0.05 was considered to be statistically significant. Compared with facilities with on-site surgical backup, the risk of in-hospital death (RR, 2.7; CI, 0.6-12.9; P = 0.18), nonfatal myocardial infarction (RR, 1.3; CI, 0.7- 2.2; P = 0.29), and need of emergent coronary artery bypass grafting (RR, 0.46; CI, 0.06- 3.1; P = 0.43) was similar in those lacking on-site surgical backup. The present meta-analysis suggests that there is no difference in the outcome with regard to risk of nonfatal myocardial infarction, need for emergency coronary artery bypass grafting, and the risk of death in patients undergoing elective PCI in hospitals with and without on-site cardiac surgery backup.

Global site-specific analysis of glycoprotein N-glycan processing.

PubMed

Cao, Liwei; Diedrich, Jolene K; Ma, Yuanhui; Wang, Nianshuang; Pauthner, Matthias; Park, Sung-Kyu Robin; Delahunty, Claire M; McLellan, Jason S; Burton, Dennis R; Yates, John R; Paulson, James C

2018-06-01

N-glycans contribute to the folding, stability and functions of the proteins they decorate. They are produced by transfer of the glycan precursor to the sequon Asn-X-Thr/Ser, followed by enzymatic trimming to a high-mannose-type core and sequential addition of monosaccharides to generate complex-type and hybrid glycans. This process, mediated by the concerted action of multiple enzymes, produces a mixture of related glycoforms at each glycosite, making analysis of glycosylation difficult. To address this analytical challenge, we developed a robust semiquantitative mass spectrometry (MS)-based method that determines the degree of glycan occupancy at each glycosite and the proportion of N-glycans processed from high-mannose type to complex type. It is applicable to virtually any glycoprotein, and a complete analysis can be conducted with 30 μg of protein. Here, we provide a detailed description of the method that includes procedures for (i) proteolytic digestion of glycoprotein(s) with specific and nonspecific proteases; (ii) denaturation of proteases by heating; (iii) sequential treatment of the glycopeptide mixture with two endoglycosidases, Endo H and PNGase F, to create unique mass signatures for the three glycosylation states; (iv) LC-MS/MS analysis; and (v) data analysis for identification and quantitation of peptides for the three glycosylation states. Full coverage of site-specific glycosylation of glycoproteins is achieved, with up to thousands of high-confidence spectra hits for each glycosite. The protocol can be performed by an experienced technician or student/postdoc with basic skills for proteomics experiments and takes ∼7 d to complete.

Visibility Analysis of Domestic Satellites on Proposed Ground Sites for Optical Surveillance

NASA Astrophysics Data System (ADS)

Kim, Jae-Hyuk; Jo, Jung Hyun; Choi, Jin; Moon, Hong-Kyu; Choi, Young-Jun; Yim, Hong-Suh; Park, Jang-Hyun; Park, Eun-Seo; Park, Jong-Uk

2011-12-01

The objectives of this study are to analyze the satellite visibility at the randomly established ground sites, to determine the five optimal ground sites to perform the optical surveillance and tracking of domestic satellites, and to verify the acquisition of the optical observation time sufficient to maintain the precise ephemeris at optimal ground sites that have been already determined. In order to accomplish these objectives, we analyzed the visibility for sun-synchronous orbit satellites, low earth orbit satellites, middle earth orbit satellites and domestic satellites as well as the continuous visibility along with the fictitious satellite ground track, and calculate the effective visibility. For the analysis, we carried out a series of repetitive process using the satellite tool kit simulation software developed by Analytical Graphics Incorporated. The lighting states of the penumbra and direct sun were set as the key constraints of the optical observation. The minimum of the observation satellite elevation angle was set to be 20 degree, whereas the maximum of the sun elevation angle was set to be -10 degree which is within the range of the nautical twilight. To select the candidates for the optimal optical observation, the entire globe was divided into 84 sectors in a constant interval, the visibility characteristics of the individual sectors were analyzed, and 17 ground sites were arbitrarily selected and analyzed further. Finally, five optimal ground sites (Khurel Togoot Observatory, Assy-Turgen Observatory, Tubitak National Observatory, Bisdee Tier Optical Astronomy Observatory, and South Africa Astronomical Observatory) were determined. The total observation period was decided as one year. To examine the seasonal variation, the simulation was performed for the period of three days or less with respect to spring, summer, fall and winter. In conclusion, we decided the optimal ground sites to perform the optical surveillance and tracking of domestic

Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE-RBS

NASA Astrophysics Data System (ADS)

Zhou, Z.; Zhang, K.; Xia, C. D.; Liu, M. T.; Zhu, J. J.; An, Z.; Bai, B.

2015-03-01

A method combining proton-induced X-ray emission spectrometry (PIXE) and Rutherford backscattering spectrometry (RBS) was used to determine the composition of 61 porcelain shards from the Yuan Dynasty (1271-1368 A.D.) unearthed from the Waguantan kiln site at Tianzhu County in Guizhou Province, China. Based on our previous experimental setup, an electron gun device with a LaB6 crystal cathode was installed to solve the problem created when the incident proton beams generated electric charge accumulations on the surfaces of the insulating porcelain samples, which induced a large bremsstrahlung background. The use of the electron gun has largely eliminated the large bremsstrahlung background and has therefore improved the detection limits for elements, especially for trace elements, and made it possible to determine the origin of the porcelains based on the trace elements. Major and trace elemental compositions of the porcelain bodies and glazes measured by PIXE and RBS were analyzed by the factor analysis method. The factor analysis showed that a few pieces of porcelain with a style similar to the porcelain of the Longquan kiln among the unearthed porcelains from the Waguantan kiln site did not have obvious differences in elemental compositions from other remaining porcelains unearthed from the Waguantan kiln site, indicating that the pieces of unearthed porcelain with the Longquan kiln style did in fact belong to the product fired locally by imitating the model of the Longquan celadon with local raw materials. This result therefore indicated that the Longquan kiln technology that originated from the Five Dynasties (907-960 A.D.) had been propagated to the Waguantan kiln site of Guizhou Province in the Yuan Dynasty.

Library Web Sites in Pakistan: An Analysis of Content

ERIC Educational Resources Information Center

Qutab, Saima; Mahmood, Khalid

2009-01-01

Purpose: The purpose of this paper is to investigate library web sites in Pakistan, to analyse their content and navigational strengths and weaknesses and to give recommendations for developing better web sites and quality assessment studies. Design/methodology/approach: Survey of web sites of 52 academic, special, public and national libraries in…

Analysis of ORNL site temperature and humidity data

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

Willis, B.E.

1989-08-01

The Advanced Neutron Source (ANS) is planned as a new state-of-the-art facility for neutron research and is currently undergoing conceptual design at the Oak Ridge National Laboratory (ORNL). The current concept calls for a nuclear research reactor with an operating power near 350 MW and extensive experiment and user support facilities. Analyses have been undertaken to determine an acceptable design basis wet-bulb temperature range for the facility. Comparisons are drawn with the design wet-bulb temperature previously used for the High Flux Isotope Reactor (HFIR), which is located on an adjacent site a Oak Ridge. This report explains the importance ofmore » wet-bulb temperature to the reactor cooling system performance, and describes the analysis of available meteorological data, and presents the results and the recommendations for a wet-bulb temperature range for use as a part of the plant design basis conditions. 1 ref., 6 figs.« less

Fabrication, characterization, and potential application of carbon fiber cone nanometer-size electrodes.

PubMed

Zhang, X; Zhang, W; Zhou, X; Ogorevc, B

1996-10-01

A novel method has been developed for the fabrication of carbon fiber cone nanometer-size ultramicroelectrodes (nanoelectrodes) with overall tip dimensions as small as 50 nm in diameter. In this method, carbon fibers were initially etched by an argon ion beam thinner. Afterward, a single etched carbon fiber was inserted into a glass capillary, which was then sealed by heating the glass/fiber interface in a vacuum; thus, no epoxy resin is involved. The success rate of our fabrication route for the electrodes with overall tip diameters of up to 500 nm was about 80%; for those with tip diameters of up to 100 nm, it was about 50%. The fabricated carbon fiber cone nanoelectrodes (CFCNEs) were inspected by optical and scanning electron microscopy. Their electrochemical behavior was examined by cyclic and linear sweep voltammetric measurements of ferricyanide and ferrocene ions in aqueous and nonaqueous media. The potential analytical applicability of the CFCNEs was tested by differential pulse voltammetric measurements of two well-known neurotransmitters, dopamine (DA) and 5-hydroxytryptamine (5-HT), and the results achieved were highly satisfactory. The calibration plots obtained were linear over the ranges from 5.0 × 10(-7) to 1.0 × 10(-4) and from 2.0 × 10(-6) to 1.0 × 10(-4) mol/L, with limits of detection of 1.0 × 10(-7) and 5.0 × 10(-7) mol/L for DA and 5-HT, respectively. Some advantages and improvements of the proposed CFCNE fabrication method, especially with respect to smoothness of the fiber (electrode) surface, strength, and control over the fiber tip dimensions, are also discussed.

Hydration sites of unpaired RNA bases: a statistical analysis of the PDB structures

PubMed Central

2011-01-01

Background Hydration is crucial for RNA structure and function. X-ray crystallography is the most commonly used method to determine RNA structures and hydration and, therefore, statistical surveys are based on crystallographic results, the number of which is quickly increasing. Results A statistical analysis of the water molecule distribution in high-resolution X-ray structures of unpaired RNA nucleotides showed that: different bases have the same penchant to be surrounded by water molecules; clusters of water molecules indicate possible hydration sites, which, in some cases, match those of the major and minor grooves of RNA and DNA double helices; complex hydrogen bond networks characterize the solvation of the nucleotides, resulting in a significant rigidity of the base and its surrounding water molecules. Interestingly, the hydration sites around unpaired RNA bases do not match, in general, the positions that are occupied by the second nucleotide when the base-pair is formed. Conclusions The hydration sites around unpaired RNA bases were found. They do not replicate the atom positions of complementary bases in the Watson-Crick pairs. PMID:22011380

Hydration sites of unpaired RNA bases: a statistical analysis of the PDB structures.

PubMed

Kirillova, Svetlana; Carugo, Oliviero

2011-10-19

Hydration is crucial for RNA structure and function. X-ray crystallography is the most commonly used method to determine RNA structures and hydration and, therefore, statistical surveys are based on crystallographic results, the number of which is quickly increasing. A statistical analysis of the water molecule distribution in high-resolution X-ray structures of unpaired RNA nucleotides showed that: different bases have the same penchant to be surrounded by water molecules; clusters of water molecules indicate possible hydration sites, which, in some cases, match those of the major and minor grooves of RNA and DNA double helices; complex hydrogen bond networks characterize the solvation of the nucleotides, resulting in a significant rigidity of the base and its surrounding water molecules. Interestingly, the hydration sites around unpaired RNA bases do not match, in general, the positions that are occupied by the second nucleotide when the base-pair is formed. The hydration sites around unpaired RNA bases were found. They do not replicate the atom positions of complementary bases in the Watson-Crick pairs.

An analysis of the Illinois Retail Rate Law and the Cook County waste-to-energy siting battles, 1987--2001

NASA Astrophysics Data System (ADS)

Sendzik, Mark Edward

2002-01-01

The analysis explores the environmental justice impacts of the 1998 Illinois Retail Rate Law and Cook County waste-to-energy siting proposals on the Chicago metropolitan area. Particular attention is given to the dynamics of the grassroots environmental organizations which emerged to fight the siting proposals. The organizations are examined in the context of NIMBYism, the antitoxic movement, the environmental justice movement, and mainstream environmentalism. In addition, the underlying causes for the unintended consequences of the Retail Rate Law are analyzed against the backdrop of market and government failure. Face-to-face and telephone interviews were conducted with forty-one persons familiar with the battles over the Cook County siting proposals and the efforts to repeal the Retail Rate Law. The term "environmental justice" became controversial as siting opponents and supporters both appropriated the issue to support dueling positions on the proposed sitings. However, environmental justice did not play an instrumental role in repealing the Retail Rate Law or the siting proposals. Economic concerns led to the repeal of the legislation and demise of the original siting proposals. The circumstances of the siting battles and opposition groups raise questions about the future effectiveness of the environmental justice movement. A combination of market and government failure led to the unintended consequences from the retail Rate Law. Strategic maneuvering by state legislative leaders delayed the repeal of the legislation by several years. The resulting delay placed considerable cost on individuals, communities, corporations, and the State of Illinois. A bivariate analysis was conducted to examine whether the distribution patterns of ground level concentrations from the proposed facilities would have had a disproportionate distribution in lower-income and minority populations in the Chicago metropolitan area. The statistical analysis did discover evidence that

Metastatic site location influences the diagnostic accuracy of ctDNA EGFR- mutation testing in NSCLC patients: a pooled analysis.

PubMed

Passiglia, Francesco; Rizzo, Sergio; Rolfo, Christian; Galvano, Antonio; Bronte, Enrico; Incorvaia, Lorena; Listi, Angela; Barraco, Nadia; Castiglia, Marta; Calo, Valentina; Bazan, Viviana; Russo, Antonio

2018-03-08

Recent studies evaluated the diagnostic accuracy of circulating tumor DNA (ctDNA) in the detection of epidermal growth factor receptor (EGFR) mutations from plasma of NSCLC patients, overall showing a high concordance as compared to standard tissue genotyping. However it is less clear if the location of metastatic site may influence the ability to identify EGFR mutations in plasma. This pooled analysis aims to evaluate the association between the metastatic site location and the sensitivity of ctDNA analysis in detecting EGFR mutations in NSCLC patients. Data from all published studies, evaluating the sensitivity of plasma-based EGFR-mutation testing, stratified by metastatic site location (extrathoracic (M1b) vs intrathoracic (M1a)) were collected by searching in PubMed, Cochrane Library, American Society of Clinical Oncology, and World Conference of Lung Cancer, meeting proceedings. Pooled Odds ratio (OR) and 95% confidence intervals (95% CIs) were calculated for the ctDNA analysis sensitivity, according to metastatic site location. A total of ten studies, with 1425 patients, were eligible. Pooled analysis showed that the sensitivity of ctDNA-based EGFR-mutation testing is significantly higher in patients with M1b vs M1a disease (OR: 5.09; 95% CIs: 2.93 - 8.84). A significant association was observed for both EGFR-activating (OR: 4.30, 95% CI: 2.35-7.88) and resistant T790M mutations (OR: 11.89, 95% CI: 1.45-97.22), regardless of the use of digital-PCR (OR: 5.85, 95% CI: 3.56-9.60) or non-digital PCR technologies (OR: 2.96, 95% CI: 2.24-3.91). These data suggest that the location of metastatic sites significantly influences the diagnostic accuracy of ctDNA analysis in detecting EGFR mutations in NSCLC patients. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Fuel cell on-site integrated energy system parametric analysis of a residential complex

NASA Technical Reports Server (NTRS)

Simons, S. N.

1977-01-01

A parametric energy-use analysis was performed for a large apartment complex served by a fuel cell on-site integrated energy system (OS/IES). The variables parameterized include operating characteristics for four phosphoric acid fuel cells, eight OS/IES energy recovery systems, and four climatic locations. The annual fuel consumption for selected parametric combinations are presented and a breakeven economic analysis is presented for one parametric combination. The results show fuel cell electrical efficiency and system component choice have the greatest effect on annual fuel consumption; fuel cell thermal efficiency and geographic location have less of an effect.

Food marketing on popular children's web sites: a content analysis.

PubMed

Alvy, Lisa M; Calvert, Sandra L

2008-04-01

In 2006 the Institute of Medicine (IOM) concluded that food marketing was a contributor to childhood obesity in the United States. One recommendation of the IOM committee was for research on newer marketing venues, such as Internet Web sites. The purpose of this cross-sectional study was to answer the IOM's call by examining food marketing on popular children's Web sites. Ten Web sites were selected based on market research conducted by KidSay, which identified favorite sites of children aged 8 to 11 years during February 2005. Using a standardized coding form, these sites were examined page by page for the existence, type, and features of food marketing. Web sites were compared using chi2 analyses. Although food marketing was not pervasive on the majority of the sites, seven of the 10 Web sites contained food marketing. The products marketed were primarily candy, cereal, quick serve restaurants, and snacks. Candystand.com, a food product site, contained a significantly greater amount of food marketing than the other popular children's Web sites. Because the foods marketed to children are not consistent with a healthful diet, nutrition professionals should consider joining advocacy groups to pressure industry to reduce online food marketing directed at youth.

Temporary disaster debris management site identification using binomial cluster analysis and GIS.

PubMed

Grzeda, Stanislaw; Mazzuchi, Thomas A; Sarkani, Shahram

2014-04-01

An essential component of disaster planning and preparation is the identification and selection of temporary disaster debris management sites (DMS). However, since DMS identification is a complex process involving numerous variable constraints, many regional, county and municipal jurisdictions initiate this process during the post-disaster response and recovery phases, typically a period of severely stressed resources. Hence, a pre-disaster approach in identifying the most likely sites based on the number of locational constraints would significantly contribute to disaster debris management planning. As disasters vary in their nature, location and extent, an effective approach must facilitate scalability, flexibility and adaptability to variable local requirements, while also being generalisable to other regions and geographical extents. This study demonstrates the use of binomial cluster analysis in potential DMS identification in a case study conducted in Hamilton County, Indiana. © 2014 The Author(s). Disasters © Overseas Development Institute, 2014.

Novel nanometer-level uniform amorphous carbon coating for boron powders by direct pyrolysis of coronene without solvent.

PubMed

Ye, ShuJun; Song, MingHui; Kumakura, Hiroaki

2015-01-30

A 3 nm coronene coating and a 4 nm amorphous carbon coating with a uniform shell-core encapsulation structure for nanosized boron (B) powders are formed by a simple process in which coronene is directly mixed with boron particles without a solvent and heated at 520 °C for 1 h or at 630 °C for 3 h in a vacuum-sealed silica tube. Coronene has a melting point lower than its decomposition temperature, which enables liquid coronene to cover B particles by liquid diffusion and penetration without the need for a solvent. The diffusion and penetration of coronene can extend to the boundaries of particles and to inside the agglomerated nanoparticles to form a complete shell-core encapsulated structure. As the temperature is increased, thermal decomposition of coronene on the B particles results in the formation of a uniform amorphous carbon coating layer. This novel and simple nanometer-level uniform amorphous carbon coating method can possibly be applied to many other powders; thus, it has potential applications in many fields at low cost.

Systematic Functional Analysis of Active-Site Residues in l-Threonine Dehydrogenase from Thermoplasma volcanium

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

Desjardins, Morgan; Mak, Wai Shun; O’Brien, Terrence E.

Enzymes have been through millions of years of evolution during which their active-site microenvironments are fine-tuned. Active-site residues are commonly conserved within protein families, indicating their importance for substrate recognition and catalysis. In this work, we systematically mutated active-site residues of l-threonine dehydrogenase from Thermoplasma volcanium and characterized the mutants against a panel of substrate analogs. Our results demonstrate that only a subset of these residues plays an essential role in substrate recognition and catalysis and that the native enzyme activity can be further enhanced roughly 4.6-fold by a single point mutation. Kinetic characterization of mutants on substrate analogs showsmore » that l-threonine dehydrogenase possesses promiscuous activities toward other chemically similar compounds not previously observed. Quantum chemical calculations on the hydride-donating ability of these substrates also reveal that this enzyme did not evolve to harness the intrinsic substrate reactivity for enzyme catalysis. Our analysis provides insights into connections between the details of enzyme active-site structure and specific function. Finally, these results are directly applicable to rational enzyme design and engineering.« less

Systematic Functional Analysis of Active-Site Residues in l-Threonine Dehydrogenase from Thermoplasma volcanium

DOE PAGES

Desjardins, Morgan; Mak, Wai Shun; O’Brien, Terrence E.; ...

2017-07-07

Enzymes have been through millions of years of evolution during which their active-site microenvironments are fine-tuned. Active-site residues are commonly conserved within protein families, indicating their importance for substrate recognition and catalysis. In this work, we systematically mutated active-site residues of l-threonine dehydrogenase from Thermoplasma volcanium and characterized the mutants against a panel of substrate analogs. Our results demonstrate that only a subset of these residues plays an essential role in substrate recognition and catalysis and that the native enzyme activity can be further enhanced roughly 4.6-fold by a single point mutation. Kinetic characterization of mutants on substrate analogs showsmore » that l-threonine dehydrogenase possesses promiscuous activities toward other chemically similar compounds not previously observed. Quantum chemical calculations on the hydride-donating ability of these substrates also reveal that this enzyme did not evolve to harness the intrinsic substrate reactivity for enzyme catalysis. Our analysis provides insights into connections between the details of enzyme active-site structure and specific function. Finally, these results are directly applicable to rational enzyme design and engineering.« less

Nanometer-scale characterization of laser-driven compression, shocks, and phase transitions, by x-ray scattering using free electron lasers

DOE PAGES

Kluge, T.; Rödel, C.; Rödel, M.; ...

2017-10-23

In this paper, we study the feasibility of using small angle X-ray scattering (SAXS) as a new experimental diagnostic for intense laser-solid interactions. By using X-ray pulses from a hard X-ray free electron laser, we can simultaneously achieve nanometer and femtosecond resolution of laser-driven samples. This is an important new capability for the Helmholtz international beamline for extreme fields at the high energy density endstation currently built at the European X-ray free electron laser. We review the relevant SAXS theory and its application to transient processes in solid density plasmas and report on first experimental results that confirm the feasibilitymore » of the method. Finally, we present results of two test experiments where the first experiment employs ultra-short laser pulses for studying relativistic laser plasma interactions, and the second one focuses on shock compression studies with a nanosecond laser system.« less

Particle size reduction to the nanometer range: a promising approach to improve buccal absorption of poorly water-soluble drugs

PubMed Central

Rao, Shasha; Song, Yunmei; Peddie, Frank; Evans, Allan M

2011-01-01

Poorly water-soluble drugs, such as phenylephrine, offer challenging problems for buccal drug delivery. In order to overcome these problems, particle size reduction (to the nanometer range) and cyclodextrin complexation were investigated for permeability enhancement. The apparent solubility in water and the buccal permeation of the original phenylephrine coarse powder, a phenylephrine–cyclodextrin complex and phenylephrine nanosuspensions were characterized. The particle size and particle surface properties of phenylephrine nanosuspensions were used to optimize the size reduction process. The optimized phenylephrine nanosuspension was then freeze dried and incorporated into a multi-layered buccal patch, consisting of a small tablet adhered to a mucoadhesive film, yielding a phenylephrine buccal product with good dosage accuracy and improved mucosal permeability. The design of the buccal patch allows for drug incorporation without the need to change the mucoadhesive component, and is potentially suited to a range of poorly water-soluble compounds. PMID:21753876

Particle size reduction to the nanometer range: a promising approach to improve buccal absorption of poorly water-soluble drugs.

PubMed

Rao, Shasha; Song, Yunmei; Peddie, Frank; Evans, Allan M

2011-01-01

Poorly water-soluble drugs, such as phenylephrine, offer challenging problems for buccal drug delivery. In order to overcome these problems, particle size reduction (to the nanometer range) and cyclodextrin complexation were investigated for permeability enhancement. The apparent solubility in water and the buccal permeation of the original phenylephrine coarse powder, a phenylephrine-cyclodextrin complex and phenylephrine nanosuspensions were characterized. The particle size and particle surface properties of phenylephrine nanosuspensions were used to optimize the size reduction process. The optimized phenylephrine nanosuspension was then freeze dried and incorporated into a multi-layered buccal patch, consisting of a small tablet adhered to a mucoadhesive film, yielding a phenylephrine buccal product with good dosage accuracy and improved mucosal permeability. The design of the buccal patch allows for drug incorporation without the need to change the mucoadhesive component, and is potentially suited to a range of poorly water-soluble compounds.

Nanometer-scale characterization of laser-driven compression, shocks, and phase transitions, by x-ray scattering using free electron lasers

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

Kluge, T.; Rödel, C.; Rödel, M.

In this paper, we study the feasibility of using small angle X-ray scattering (SAXS) as a new experimental diagnostic for intense laser-solid interactions. By using X-ray pulses from a hard X-ray free electron laser, we can simultaneously achieve nanometer and femtosecond resolution of laser-driven samples. This is an important new capability for the Helmholtz international beamline for extreme fields at the high energy density endstation currently built at the European X-ray free electron laser. We review the relevant SAXS theory and its application to transient processes in solid density plasmas and report on first experimental results that confirm the feasibilitymore » of the method. Finally, we present results of two test experiments where the first experiment employs ultra-short laser pulses for studying relativistic laser plasma interactions, and the second one focuses on shock compression studies with a nanosecond laser system.« less

Prioritizing conservation activities using reserve site selection methods and population viability analysis.

PubMed

Newbold, Stephen C; Siikamäki, Juha

2009-10-01

In recent years a large literature on reserve site selection (RSS) has developed at the interface between ecology, operations research, and environmental economics. Reserve site selection models use numerical optimization techniques to select sites for a network of nature reserves for protecting biodiversity. In this paper, we develop a population viability analysis (PVA) model for salmon and incorporate it into an RSS framework for prioritizing conservation activities in upstream watersheds. We use spawner return data for three closely related salmon stocks in the upper Columbia River basin and estimates of the economic costs of watershed protection from NOAA to illustrate the framework. We compare the relative cost-effectiveness of five alternative watershed prioritization methods, based on various combinations of biological and economic information. Prioritization based on biological benefit-economic cost comparisons and accounting for spatial interdependencies among watersheds substantially outperforms other more heuristic methods. When using this best-performing prioritization method, spending 10% of the cost of protecting all upstream watersheds yields 79% of the biological benefits (increase in stock persistence) from protecting all watersheds, compared to between 20% and 64% for the alternative methods. We also find that prioritization based on either costs or benefits alone can lead to severe reductions in cost-effectiveness.

Just one click: a content analysis of advertisements on teen web sites.

PubMed

Slater, Amy; Tiggemann, Marika; Hawkins, Kimberley; Werchon, Douglas

2012-04-01

The current study provides a comprehensive analysis of the content of advertisements on Web sites targeted at adolescents, with a particular focus on the female beauty ideal. Advertisements (N = 631) from 14 Web sites popular with adolescents were analyzed with respect to product advertised, characteristics of people presented, and emphasis on appearance and the thin beauty ideal. Although a wide variety of products were featured, advertisements for cosmetics and beauty products were the most frequent. Further, many of the products advertised (e.g., dating services, weight loss products, gambling games) might be considered inappropriate for the intended audience (i.e., teenagers) of the Web site. People who were a part of advertisements were generally female, young, thin, and attractive. Advertisements for games, weight loss products, and cosmetic and beauty products strongly focused on appearance and laid emphasis on the thin ideal. Like advertisements in mainstream media, advertising on the Internet perpetuates the stereotypical ideal of feminine beauty. Adolescents using the Internet are likely to be exposed to numerous advertisements that reinforce the importance of beauty and thinness, which could have a detrimental impact on how they feel about their bodies. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Content analysis of male participation in pro-eating disorder web sites.

PubMed

Wooldridge, Tom; Mok, Caroline; Chiu, Sabrina

2014-01-01

The pro-anorexia community has emerged as a powerful cultural movement that takes an at least partially positive attitude toward anorexia nervosa and other eating disorders. A systematic review of the literature on pro-ana forums focused specifically on females with eating disorders. However, epidemiological data suggest that as much as 25% of the eating disorders population is male. In our review of pro-anorexia web sites, we found a substantial number of participants were male. We conducted a qualitative content analysis of male participation in pro-ana forums in an effort to learn more about male participation in these forums. In this article, we present the results of this analysis, highlighting themes of social support, community appreciation, and ambivalence, as well as themes that appear to be particular to the male experience of eating disorders, such as alienation and teasing.

Social Capital, Self-Esteem, and Use of Online Social Network Sites: A Longitudinal Analysis

ERIC Educational Resources Information Center

Steinfield, Charles; Ellison, Nicole B.; Lampe, Cliff

2008-01-01

A longitudinal analysis of panel data from users of a popular online social network site, Facebook, investigated the relationship between intensity of Facebook use, measures of psychological well-being, and bridging social capital. Two surveys conducted a year apart at a large U.S. university, complemented with in-depth interviews with 18 Facebook…

Systematic analysis of transcription start sites in avian development.

PubMed

Lizio, Marina; Deviatiiarov, Ruslan; Nagai, Hiroki; Galan, Laura; Arner, Erik; Itoh, Masayoshi; Lassmann, Timo; Kasukawa, Takeya; Hasegawa, Akira; Ros, Marian A; Hayashizaki, Yoshihide; Carninci, Piero; Forrest, Alistair R R; Kawaji, Hideya; Gusev, Oleg; Sheng, Guojun

2017-09-01

Cap Analysis of Gene Expression (CAGE) in combination with single-molecule sequencing technology allows precision mapping of transcription start sites (TSSs) and genome-wide capture of promoter activities in differentiated and steady state cell populations. Much less is known about whether TSS profiling can characterize diverse and non-steady state cell populations, such as the approximately 400 transitory and heterogeneous cell types that arise during ontogeny of vertebrate animals. To gain such insight, we used the chick model and performed CAGE-based TSS analysis on embryonic samples covering the full 3-week developmental period. In total, 31,863 robust TSS peaks (>1 tag per million [TPM]) were mapped to the latest chicken genome assembly, of which 34% to 46% were active in any given developmental stage. ZENBU, a web-based, open-source platform, was used for interactive data exploration. TSSs of genes critical for lineage differentiation could be precisely mapped and their activities tracked throughout development, suggesting that non-steady state and heterogeneous cell populations are amenable to CAGE-based transcriptional analysis. Our study also uncovered a large set of extremely stable housekeeping TSSs and many novel stage-specific ones. We furthermore demonstrated that TSS mapping could expedite motif-based promoter analysis for regulatory modules associated with stage-specific and housekeeping genes. Finally, using Brachyury as an example, we provide evidence that precise TSS mapping in combination with Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-on technology enables us, for the first time, to efficiently target endogenous avian genes for transcriptional activation. Taken together, our results represent the first report of genome-wide TSS mapping in birds and the first systematic developmental TSS analysis in any amniote species (birds and mammals). By facilitating promoter-based molecular analysis and genetic manipulation, our work

Environmental siting suitability analysis for commercial scale ocean renewable energy: A southeast Florida case study

NASA Astrophysics Data System (ADS)

Mulcan, Amanda

This thesis aims to facilitate the siting and implementation of Florida Atlantic University Southeast National Marine Renewable Energy Center (FAU SNMREC) ocean current energy (OCE) projects offshore southeastern Florida through the analysis of benthic anchoring conditions. Specifically, a suitability analysis considering all presently available biologic and geologic datasets within the legal framework of OCE policy and regulation was done. OCE related literature sources were consulted to assign suitability levels to each dataset, ArcGIS interpolations generated seafloor substrate maps, and existing submarine cable pathways were considered for OCE power cables. The finalized suitability map highlights the eastern study area as most suitable for OCE siting due to its abundance of sand/sediment substrate, existing underwater cable route access, and minimal biologic presence. Higher resolution datasets are necessary to locate specific OCE development locales, better understand their benthic conditions, and minimize potentially negative OCE environmental impacts.

Quantification of source impact to PM using three-dimensional weighted factor model analysis on multi-site data

NASA Astrophysics Data System (ADS)

Shi, Guoliang; Peng, Xing; Huangfu, Yanqi; Wang, Wei; Xu, Jiao; Tian, Yingze; Feng, Yinchang; Ivey, Cesunica E.; Russell, Armistead G.

2017-07-01

Source apportionment technologies are used to understand the impacts of important sources of particulate matter (PM) air quality, and are widely used for both scientific studies and air quality management. Generally, receptor models apportion speciated PM data from a single sampling site. With the development of large scale monitoring networks, PM speciation are observed at multiple sites in an urban area. For these situations, the models should account for three factors, or dimensions, of the PM, including the chemical species concentrations, sampling periods and sampling site information, suggesting the potential power of a three-dimensional source apportionment approach. However, the principle of three-dimensional Parallel Factor Analysis (Ordinary PARAFAC) model does not always work well in real environmental situations for multi-site receptor datasets. In this work, a new three-way receptor model, called "multi-site three way factor analysis" model is proposed to deal with the multi-site receptor datasets. Synthetic datasets were developed and introduced into the new model to test its performance. Average absolute error (AAE, between estimated and true contributions) for extracted sources were all less than 50%. Additionally, three-dimensional ambient datasets from a Chinese mega-city, Chengdu, were analyzed using this new model to assess the application. Four factors are extracted by the multi-site WFA3 model: secondary source have the highest contributions (64.73 and 56.24 μg/m3), followed by vehicular exhaust (30.13 and 33.60 μg/m3), crustal dust (26.12 and 29.99 μg/m3) and coal combustion (10.73 and 14.83 μg/m3). The model was also compared to PMF, with general agreement, though PMF suggested a lower crustal contribution.

Histological and histomorphometric evaluation of implant with nanometer scale and oxidized surface. in vitro and in vivo study.

PubMed

Corvino, V; Iezzi, G; Trubiani, O; Traini, T; Piattelli, M

2012-01-01

The biological fixation of an implant to bone is influenced by numerous factors, including surface chemistry and surface topography. Various methods have been developed to create rough implant surfaces in order to improve the clinical performance of implants and to guarantee a stable mechanical bone-implant interface. Anodic oxidation is a dental implant surface modification technique that results in oxide layer growth up to a thickness of 1–10 micron. The purpose of this study was to evaluate the performance of the surface through the osteoblasts cells growth and the influence of oxidixed surface on BIC percent, in the human posterior maxilla after 2 months of unloaded healing. In vitro commercially available primary human osteoblasts (NHOst) from both femur and tibia of different donor systems (Lonza Walkersville Inc, Walkersville, MD, USA) were grown in Osteoblast Growth Media (OBM) (Lonza). Osteogenic differentiation was induced for a period of 4 weeks by the OGM medium (OBM basal medium supplemented with 200nM of hydrocortisone-21-hemisuccinate and 7.5 mM of glycerophosphate). The viability of NHOst cells seeded test A and B was measured by the quantitative colorimetric MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2Htetrazoliumbromide test) (Promega, Milan, Italy). One custom-made 2 x 10-mm site evaluation implant (SEI) with nanometer scale and oxidized surface (test) ( Evo Plan 1 Health s.r.l. - Amaro, UD, Italy), and one SEI with hydroxyapatite sandblasted surface (control) (Osseogrip Plan 1 Health s.r.l. – Amaro, UD, Italy), were placed in the posterior maxilla of 15 patients. Patients received one of each type of SEI placed on controlateral side. The proliferation rate studied by the MTT assay showed that during the incubation time, starting at 24 h, an increased proliferation rate was evident in Test B respect to Test A. After 2 months of unloaded healing BIC percent was significantly higher in oxidized implants. BIC percent mean values for the

Tomographic phase analysis to detect the site of accessory conduction pathway in Wolff-Parkinson-White syndrome

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

Nakajima, K.; Bunko, H.; Tada, A.

1984-01-01

Phase analysis has been applied to Wolff-Parkinson-White syndrome (WPW) to detect the site of accessory conduction pathway (ACP); however, there was a limitation to estimate the precise location of ACP by planar phase analysis. In this study, the authors applied phase analysis to gated blood pool tomography. Twelve patients with WPW who underwent epicardial mapping and surgical division of ACP were studied by both of gated emission computed tomography (GECT) and routine gated blood pool study (GBPS). The GBPS was performed with Tc-99m red blood cells in multiple projections; modified left anterior oblique, right anterior oblique and/or left lateral views.more » In GECT, short axial, horizontal and vertical long axial blood pool images were reconstructed. Phase analysis was performed using fundamental frequency of the Fourier transform in both GECT and GBPS images, and abnormal initial contractions on both the planar and tomographic phase analysis were compared with the location of surgically confirmed ACPs. In planar phase analysis, abnormal initial phase was identified in 7 out of 12 (58%) patients, while in tomographic phase analysis, the localization of ACP was predicted in 11 out of 12 (92%) patients. Tomographic phase analysis is superior to planar phase images in 8 out of 12 patients to estimate the location of ACP. Phase analysis by GECT can avoid overlap of blood pool in cardiac chambers and has advantage to identify the propagation of phase three-dimensionally. Tomographic phase analysis is a good adjunctive method for patients with WPW to estimate the site of ACP.« less

Analysis of the site-specific integration system of the Streptomyces aureofaciens phage μ1/6.

PubMed

Farkašovská, Jarmila; Godány, Andrej

2012-03-01

The bacteriophage μ1/6 integrates its DNA into the chromosome of tetracycline producing strains of Streptomyces aureofaciens by a site-specific recombination process. A bioinformatic analysis of the μ1/6 genome revealed that orf5 encodes a putative integrase, a basic protein of 416 amino acids. The μ1/6 integrase was found to belong to the integrase family of site-specific tyrosine recombinases. The phage attachment site (attP) was localized downstream of the int gene. The attachment junctions (attL and attR) were determined, allowing identification of the bacterial attachment site (attB). All attachment sites shared a 46-bp common core sequence within which a site-specific recombination occurs. This core sequence comprises the 3' end of a putative tRNA(Thr) gene (anticodon TGT) which is completely restored in attL after integration of the phage into the host genome. An integration vector containing μ1/6 int-attP region was inserted stably into the S. aureofaciens B96, S. lividans TK24, and S. coelicolor A3. The μ1/6 integrase was shown to be functional in vivo in heterologous Escherichia coli without any other factors encoded by Streptomyces. In vitro recombination assay using purified μ1/6 integrase demonstrated its ability to catalyze integrative recombination in the presence of a crude extract of E. coli cells.

In situ trapping of As, Sb and Se hydrides on nanometer-sized ceria-coated iron oxide-silica and slurry suspension introduction to ICP-OES.

PubMed

Dados, A; Kartsiouli, E; Chatzimitakos, Th; Papastephanou, C; Stalikas, C D

2014-12-01

A procedure is developed for the analysis of sub-μg L(-1) levels of arsenic, antimony and selenium after preconcentration of their hydrides. The study highlights the capability of an aqueous suspension of a nanometer-sized magnetic ceria, in the presence of iodide, to function as a sorbent for the in situ trapping and preconcentration of the hydrides of certain metalloids. After extraction, the material is magnetically separated from the trapping solution and analyzed. A slurry suspension sampling approach with inductively coupled plasma-optical emission spectrometry (ICP-OES) is employed for measurements, as the quantitative elution of the adsorbed metalloids is not feasible. The whole analytical procedure consists of five steps: (i) pre-reduction of As, Sb and Se, (ii) generation of the hydrides AsH3, SbH3 and SeH2, (iii) in situ collection in the trapping suspension of magnetic ceria, (iv) isolation of the particles by applying a magnetic field, and (v) measurement of As, Sb and Se concentrations using ICP-OES. Under the established experimental conditions, the efficiency of trapping accounted for 94 ± 2%, 89 ± 2% and 98 ± 3% for As, Sb and Se, respectively, signifying the effective implementation of the overall procedure. The applicability of the procedure has been demonstrated by analyzing tap and lake water and a reference material (soft drinking water). The obtained analytical figures of merit were satisfactory for the analysis of the above metalloids in natural waters by ICP-OES. Copyright © 2014 Elsevier B.V. All rights reserved.

Site Classification using Multichannel Channel Analysis of Surface Wave (MASW) method on Soft and Hard Ground

NASA Astrophysics Data System (ADS)

Ashraf, M. A. M.; Kumar, N. S.; Yusoh, R.; Hazreek, Z. A. M.; Aziman, M.

2018-04-01

Site classification utilizing average shear wave velocity (Vs(30) up to 30 meters depth is a typical parameter. Numerous geophysical methods have been proposed for estimation of shear wave velocity by utilizing assortment of testing configuration, processing method, and inversion algorithm. Multichannel Analysis of Surface Wave (MASW) method is been rehearsed by numerous specialist and professional to geotechnical engineering for local site characterization and classification. This study aims to determine the site classification on soft and hard ground using MASW method. The subsurface classification was made utilizing National Earthquake Hazards Reduction Program (NERHP) and international Building Code (IBC) classification. Two sites are chosen to acquire the shear wave velocity which is in the state of Pulau Pinang for soft soil and Perlis for hard rock. Results recommend that MASW technique can be utilized to spatially calculate the distribution of shear wave velocity (Vs(30)) in soil and rock to characterize areas.

Effectiveness of an on-site health clinic at a self-insured university: a cost-benefit analysis.

PubMed

McCaskill, Sherrie P; Schwartz, Lisa A; Derouin, Anne L; Pegram, Angela H

2014-04-01

This study assessed the impact and cost-effectiveness of an on-site health clinic at a self-insured university. Health care costs and number of claims filed to primary care providers were trended before and after the clinic was established to determine savings. A retrospective chart review of all full-time, insured employees treated for upper respiratory tract infections (URIs) during a 1-year study period was conducted. On-site clinic costs for the treatment of URIs were compared to costs at outside community providers for similar care. Community cost norms for the treatment of URIs were provided by Primary Physicians Care, the administrator of insurance claims for the University. A cost-benefit analysis compared the cost of services on-site versus similar services at an outside community provider. Based on the results of this study, the University's on-site health care services were determined to be more cost-effective than similar off-site health care services for the treatment of URIs. [Workplace Health Saf 2014;62(4):162-169.]. Copyright 2014, SLACK Incorporated.

40 CFR 1400.3 - Public access to paper copies of off-site consequence analysis information.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Public access to paper copies of off-site consequence analysis information. 1400.3 Section 1400.3 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY AND DEPARTMENT OF JUSTICE ACCIDENTAL RELEASE PREVENTION REQUIREMENTS; RISK MANAGEMENT...

The Role of Spatial Analysis in Detecting the Consequence of the Factory Sites : Case Study of Assalaya Factory-Sudan

NASA Astrophysics Data System (ADS)

Khair, Amar Sharaf Eldin; Purwanto; RyaSunoko, Henna; Abdullah, Omer Adam

2018-02-01

Spatial analysis is considered as one of the most important science for identifying the most appropriate site for industrialization and also to alleviate the environmental ramifications caused by factories. This study aims at analyzing the Assalaya sugarcane factory site by the use of spatial analysis to determine whether it has ramification on the White Nile River. The methodology employed for this study is Global Position System (GPS) to identify the coordinate system of the study phenomena and other relative factors. The study will also make use Geographical Information System (GIS) to implement the spatial analysis. Satellite data (LandsatDem-Digital Elevation Model) will be considered for the study area and factory in identifying the consequences by analyzing the location of the factory through several features such as hydrological, contour line and geological analysis. Data analysis reveals that the factory site is inappropriate and according to observation on the ground it has consequences on the White Nile River. Based on the finding, the study recommended some suggestions to avoid the aftermath of any factory in general. We have to take advantage of this new technological method to aid in selecting most apt locations for industries that will create an ambient environment.

Tool for Statistical Analysis and Display of Landing Sites

NASA Technical Reports Server (NTRS)

Wawrzyniak, Geoffrey; Kennedy, Brian; Knocke, Philip; Michel, John

2006-01-01

MarsLS is a software tool for analyzing statistical dispersion of spacecraft-landing sites and displaying the results of its analyses. Originally intended for the Mars Explorer Rover (MER) mission, MarsLS is also applicable to landing sites on Earth and non-MER sites on Mars. MarsLS is a collection of interdependent MATLAB scripts that utilize the MATLAB graphical-user-interface software environment to display landing-site data (see figure) on calibrated image-maps of the Martian or other terrain. The landing-site data comprise latitude/longitude pairs generated by Monte Carlo runs of other computer programs that simulate entry, descent, and landing. Using these data, MarsLS can compute a landing-site ellipse a standard means of depicting the area within which the spacecraft can be expected to land with a given probability. MarsLS incorporates several features for the user s convenience, including capabilities for drawing lines and ellipses, overlaying kilometer or latitude/longitude grids, drawing and/or specifying lines and/or points, entering notes, defining and/or displaying polygons to indicate hazards or areas of interest, and evaluating hazardous and/or scientifically interesting areas. As part of such an evaluation, MarsLS can compute the probability of landing in a specified polygonal area.

Multi-criteria analysis for the detection of the most critical European UNESCO Heritage sites

NASA Astrophysics Data System (ADS)

Valagussa, Andrea; Frattini, Paolo; Berta, Nadia; Spizzichino, Daniele; Leoni, Gabriele; Margottini, Claudio; Battista Crosta, Giovanni

2017-04-01

A GIS-based multi-criteria analysis has been implemented to identify and to rank the most critical UNESCO Heritage sites at the European scale in the context of PROTHEGO JPI-Project. Two multi-criteria methods have been tested and applied to more than 300 European UNESCO Sites. First, the Analytic Hierarchy Procedure (AHP) was applied to the data of the UNESCO Periodic Report, in relation to 13 natural hazards that have affected or can potentially affect the Heritage sites. According to these reports, 22% of sites are without any documented hazard and 70% of the sites have at least one hazard affecting the site. The most important hazards on the European country are: fire (wildfire), storm, flooding, earthquake and erosion. For each UNESCO site, the potential risk was calculated as a weighed sum of the hazards that affect the site. The weighs of the 13 hazards were obtained by AHP procedure, which is a technique for multi-attribute decision making that enables the decomposition of a problem into hierarchy, based on the opinion of different experts about the dominance of risks. The weights are obtained by rescaling between 0 and 1 the eigenvectors relative to the maximum eigenvalue for the matrix of the coefficients. The internal coherence of the expert's attributions is defined through the calculation of the consistency ratio (Saaty, 1990). The result of the AHP method consists in a map of the UNESCO sites ranked according to the potential risk, where the site most at risk results to be the Geirangerfjord and Nærøyfjord in Norway. However, the quality of these results lies in the reliability of the Period Reports, which are produced by different experts with unknown level of scientific background. To test the reliability of these results, a comparison of the information of the periodic reports with available high-quality datasets (earthquake, volcano and landslide) at the Italian scale has been performed. Sites properly classified by the Period Reports range from

Molecular Analysis of Dehalococcoides 16S Ribosomal DNA from Chloroethene-Contaminated Sites throughout North America and Europe

PubMed Central

Hendrickson, Edwin R.; Payne, Jo Ann; Young, Roslyn M.; Starr, Mark G.; Perry, Michael P.; Fahnestock, Stephen; Ellis, David E.; Ebersole, Richard C.

2002-01-01

The environmental distribution of Dehalococcoides group organisms and their association with chloroethene-contaminated sites were examined. Samples from 24 chloroethene-dechlorinating sites scattered throughout North America and Europe were tested for the presence of members of the Dehalococcoides group by using a PCR assay developed to detect Dehalococcoides 16S rRNA gene (rDNA) sequences. Sequences identified by sequence analysis as sequences of members of the Dehalococcoides group were detected at 21 sites. Full dechlorination of chloroethenes to ethene occurred at these sites. Dehalococcoides sequences were not detected in samples from three sites at which partial dechlorination of chloroethenes occurred, where dechlorination appeared to stop at 1,2-cis-dichloroethene. Phylogenetic analysis of the 16S rDNA amplicons confirmed that Dehalococcoides sequences formed a unique 16S rDNA group. These 16S rDNA sequences were divided into three subgroups based on specific base substitution patterns in variable regions 2 and 6 of the Dehalococcoides 16S rDNA sequence. Analyses also demonstrated that specific base substitution patterns were signature patterns. The specific base substitutions distinguished the three sequence subgroups phylogenetically. These results demonstrated that members of the Dehalococcoides group are widely distributed in nature and can be found in a variety of geological formations and in different climatic zones. Furthermore, the association of these organisms with full dechlorination of chloroethenes suggests that they are promising candidates for engineered bioremediation and may be important contributors to natural attenuation of chloroethenes. PMID:11823182

Water-quality trends and constituent-transport analysis for selected sampling sites in the Milltown Reservoir/Clark Fork River Superfund Site in the upper Clark Fork Basin, Montana, water years 1996–2015

USGS Publications Warehouse

Sando, Steven K.; Vecchia, Aldo V.

2016-07-20

During the extended history of mining in the upper Clark Fork Basin in Montana, large amounts of waste materials enriched with metallic contaminants (cadmium, copper, lead, and zinc) and the metalloid trace element arsenic were generated from mining operations near Butte and milling and smelting operations near Anaconda. Extensive deposition of mining wastes in the Silver Bow Creek and Clark Fork channels and flood plains had substantial effects on water quality. Federal Superfund remediation activities in the upper Clark Fork Basin began in 1983 and have included substantial remediation near Butte and removal of the former Milltown Dam near Missoula. To aid in evaluating the effects of remediation activities on water quality, the U.S. Geological Survey began collecting streamflow and water-quality data in the upper Clark Fork Basin in the 1980s.Trend analysis was done on specific conductance, selected trace elements (arsenic, copper, and zinc), and suspended sediment for seven sampling sites in the Milltown Reservoir/Clark Fork River Superfund Site for water years 1996–2015. The most upstream site included in trend analysis is Silver Bow Creek at Warm Springs, Montana (sampling site 8), and the most downstream site is Clark Fork above Missoula, Montana (sampling site 22), which is just downstream from the former Milltown Dam. Water year is the 12-month period from October 1 through September 30 and is designated by the year in which it ends. Trend analysis was done by using a joint time-series model for concentration and streamflow. To provide temporal resolution of changes in water quality, trend analysis was conducted for four sequential 5-year periods: period 1 (water years 1996–2000), period 2 (water years 2001–5), period 3 (water years 2006–10), and period 4 (water years 2011–15). Because of the substantial effect of the intentional breach of Milltown Dam on March 28, 2008, period 3 was subdivided into period 3A (October 1, 2005–March 27, 2008

Conserved nucleation sites reinforce the significance of Phi value analysis in protein-folding studies.

PubMed

Gianni, Stefano; Jemth, Per

2014-07-01

The only experimental strategy to address the structure of folding transition states, the so-called Φ value analysis, relies on the synergy between site directed mutagenesis and the measurement of reaction kinetics. Despite its importance, the Φ value analysis has been often criticized and its power to pinpoint structural information has been questioned. In this hypothesis, we demonstrate that comparing the Φ values between proteins not only allows highlighting the robustness of folding pathways but also provides per se a strong validation of the method. © 2014 International Union of Biochemistry and Molecular Biology.

A Multi-criteria Decision Analysis System for Prioritizing Sites and Types of Low Impact Development Practices

NASA Astrophysics Data System (ADS)

Song, Jae Yeol; Chung, Eun-Sung

2017-04-01

This study developed a multi-criteria decision analysis framework to prioritize sites and types of low impact development (LID) practices. This framework was systemized as a web-based system coupled with the Storm Water Management Model (SWMM) from the Environmental Protection Agency (EPA). Using the technique for order of preference by similarity to ideal solution (TOPSIS), which is a type of multi-criteria decision-making (MCDM) method, multiple types and sites of designated LID practices are prioritized. This system is named the Water Management Prioritization Module (WMPM) and is an improved version of the Water Management Analysis Module (WMAM) that automatically generates and simulates multiple scenarios of LID design and planning parameters for a single LID type. WMPM can simultaneously determine the priority of multiple LID types and sites. In this study, an infiltration trench and permeable pavement were considered for multiple sub-catchments in South Korea to demonstrate the WMPM procedures. The TOPSIS method was manually incorporated to select the vulnerable target sub-catchments and to prioritize the LID planning scenarios for multiple types and sites considering socio-economic, hydrologic and physical-geometric factors. In this application, the Delphi method and entropy theory were used to determine the subjective and objective weights, respectively. Comparing the ranks derived by this system, two sub-catchments, S16 and S4, out of 18 were considered to be the most suitable places for installing an infiltration trench and porous pavement to reduce the peak and total flow, respectively, considering both socio-economic factors and hydrological effectiveness. WMPM can help policy-makers to objectively develop urban water plans for sustainable development. Keywords: Low Impact Development, Multi-Criteria Decision Analysis, SWMM, TOPSIS, Water Management Prioritization Module (WMPM)

Imaging Nanometer Phase Coexistence at Defects During the Insulator-Metal Phase Transformation in VO2 Thin Films by Resonant Soft X-ray Holography.

PubMed

Vidas, Luciana; Günther, Christian M; Miller, Timothy A; Pfau, Bastian; Perez-Salinas, Daniel; Martínez, Elías; Schneider, Michael; Gührs, Erik; Gargiani, Pierluigi; Valvidares, Manuel; Marvel, Robert E; Hallman, Kent A; Haglund, Richard F; Eisebitt, Stefan; Wall, Simon

2018-05-18

We use resonant soft X-ray holography to image the insulator-metal phase transition in vanadium dioxide with element and polarization specificity and nanometer spatial resolution. We observe that nanoscale inhomogeneity in the film results in spatial-dependent transition pathways between the insulating and metallic states. Additional nanoscale phases form in the vicinity of defects which are not apparent in the initial or final states of the system, which would be missed in area-integrated X-ray absorption measurements. These intermediate phases are vital to understand the phase transition in VO 2 , and our results demonstrate how resonant imaging can be used to understand the electronic properties of phase-separated correlated materials obtained by X-ray absorption.

Bias and Bias Correction in Multi-Site Instrumental Variables Analysis of Heterogeneous Mediator Effects

ERIC Educational Resources Information Center

Reardon, Sean F.; Unlu, Faith; Zhu, Pei; Bloom, Howard

2013-01-01

We explore the use of instrumental variables (IV) analysis with a multi-site randomized trial to estimate the effect of a mediating variable on an outcome in cases where it can be assumed that the observed mediator is the only mechanism linking treatment assignment to outcomes, as assumption known in the instrumental variables literature as the…

Interatomic Coulombic Decay Effects in Theoretical DNA Recombination Systems Involving Protein Interaction Sites

NASA Astrophysics Data System (ADS)

Vargas, E. L.; Rivas, D. A.; Duot, A. C.; Hovey, R. T.; Andrianarijaona, V. M.

2015-03-01

DNA replication is the basis for all biological reproduction. A strand of DNA will ``unzip'' and bind with a complimentary strand, creating two identical strands. In this study, we are considering how this process is affected by Interatomic Coulombic Decay (ICD), specifically how ICD affects the individual coding proteins' ability to hold together. ICD mainly deals with how the electron returns to its original state after excitation and how this affects its immediate atomic environment, sometimes affecting the connectivity between interaction sites on proteins involved in the DNA coding process. Biological heredity is fundamentally controlled by DNA and its replication therefore it affects every living thing. The small nature of the proteins (within the range of nanometers) makes it a good candidate for research of this scale. Understanding how ICD affects DNA molecules can give us invaluable insight into the human genetic code and the processes behind cell mutations that can lead to cancer. Authors wish to give special thanks to Pacific Union College Student Senate in Angwin, California, for their financial support.

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

Vissers, Daniel R.; Isheim, Dieter; Zhan, Chun

Lithium-ion batteries utilizing 5 V spinel material, LixMn1.5Ni0.5O4 have received considerable interest in recent years for their ability to deliver high energy and power densities. In this paper, we report an atomic scale analysis of the surface layer of a core–shell 5 V spinel structure where a small amount of the manganese lattice sites have been substituted with cobalt in the shell to reach a stoichiometry of LixMn1.18Ni0.55Co0.27O4. Our analyses include electrochemical analysis, atom probe tomography (APT) analysis, kinetic analysis of the interfacial reactions, and high resolution scanning transmission electron microscopy (HR-TEM) analysis. The APT analysis is performed on themore » material before and after long-term cycling at room temperature to provide insights into the atomic scale phenomena within the surface layer of the electrode material. Our APT data reveals a 25–30 nano-meter (nm) region which forms after cycling. From our analyses, we believe that the outer few nanometers of this region stabilizes the 5 V spinel within the chemical environment of the lithium-ion cell such that its structure is not compromised and thereby enables this material to cycle without significant capacity fading.« less

Identification and Analysis of RNA Editing Sites in the Chloroplast Transcripts of Aegilops tauschii L.

PubMed Central

Wang, Mengxing; Liu, Hui; Ge, Lingqiao; Xing, Guangwei; Wang, Meng; Weining, Song; Nie, Xiaojun

2016-01-01

RNA editing is an important way to convert cytidine (C) to uridine (U) at specific sites within RNA molecules at a post-transcriptional level in the chloroplasts of higher plants. Although it has been systematically studied in many plants, little is known about RNA editing in the wheat D genome donor Aegilops tauschii L. Here, we investigated the chloroplast RNA editing of Ae. tauschii and compared it with other wheat relatives to trace the evolution of wheat. Through bioinformatics prediction, a total of 34 C-to-U editing sites were identified, 17 of which were validated using RT-PCR product sequencing. Furthermore, 60 sites were found by the RNA-Seq read mapping approach, 24 of which agreed with the prediction and six were validated experimentally. The editing sites were biased toward tCn or nCa trinucleotides and 5′-pyrimidines, which were consistent with the flanking bases of editing sites of other seed plants. Furthermore, the editing events could result in the alteration of the secondary structures and topologies of the corresponding proteins, suggesting that RNA editing might impact the function of target genes. Finally, comparative analysis found some evolutionarily conserved editing sites in wheat and two species-specific sites were also obtained. This study is the first to report on RNA editing in Aegilops tauschii L, which not only sheds light on the evolution of wheat from the point of view of RNA editing, but also lays a foundation for further studies to identify the mechanisms of C-to-U alterations. PMID:28042823

An interpretative phenomenological analysis of participation in a pro-anorexia internet site and its relationship with disordered eating.

PubMed

Mulveen, Ruaidhri; Hepworth, Julie

2006-03-01

Pro-anorexia Internet sites aim to promote, support and discuss anorexia nervosa. Media coverage has raised concerns that sites may increase the level of eating disorders. This research examines the meaning of participation in a pro-anorexia Internet site and its relationship with disordered eating by using an interpretative phenomenological analysis of fifteen separate message 'threads' followed over a six-week period. Four themes were identified: (1) tips and techniques; (2) 'ana' v. anorexia nervosa; (3) social support; and (4) need for anorexia. Findings suggest participation was multi-purpose, providing a coping function in relation to weight loss, and the contribution of sites to increased levels of eating disorders is not inevitable.

Glossary of Common Site Terms

MedlinePlus

... Maps Downloading Content for Analysis About Site What's New ClinicalTrials.gov Background About the Results Database History, Policies, and Laws Media/Press Resources Linking to This Site Terms and ...

Importance of Viral Sequence Length and Number of Variable and Informative Sites in Analysis of HIV Clustering.

PubMed

Novitsky, Vlad; Moyo, Sikhulile; Lei, Quanhong; DeGruttola, Victor; Essex, M

2015-05-01

To improve the methodology of HIV cluster analysis, we addressed how analysis of HIV clustering is associated with parameters that can affect the outcome of viral clustering. The extent of HIV clustering and tree certainty was compared between 401 HIV-1C near full-length genome sequences and subgenomic regions retrieved from the LANL HIV Database. Sliding window analysis was based on 99 windows of 1,000 bp and 45 windows of 2,000 bp. Potential associations between the extent of HIV clustering and sequence length and the number of variable and informative sites were evaluated. The near full-length genome HIV sequences showed the highest extent of HIV clustering and the highest tree certainty. At the bootstrap threshold of 0.80 in maximum likelihood (ML) analysis, 58.9% of near full-length HIV-1C sequences but only 15.5% of partial pol sequences (ViroSeq) were found in clusters. Among HIV-1 structural genes, pol showed the highest extent of clustering (38.9% at a bootstrap threshold of 0.80), although it was significantly lower than in the near full-length genome sequences. The extent of HIV clustering was significantly higher for sliding windows of 2,000 bp than 1,000 bp. We found a strong association between the sequence length and proportion of HIV sequences in clusters, and a moderate association between the number of variable and informative sites and the proportion of HIV sequences in clusters. In HIV cluster analysis, the extent of detectable HIV clustering is directly associated with the length of viral sequences used, as well as the number of variable and informative sites. Near full-length genome sequences could provide the most informative HIV cluster analysis. Selected subgenomic regions with a high extent of HIV clustering and high tree certainty could also be considered as a second choice.

Very Tiny Rocks: Site-Specific, Size-Dependent Reaction Kinetics at Nanoparticle-Water Interfaces

NASA Astrophysics Data System (ADS)

Rustad, J. R.

2008-12-01

One of the most fundamental challenges in geochemistry is to be able to understand the rates and mechanisms of elementary reactions that describe chemical processes occurring at mineral-water interfaces. One of the reasons for the primitive conceptual state of reaction kinetics in solid earth geochemistry is that it is very difficult to identify defensible elementary reactions where theoretical predictions can be made and the results can tested experimentally at the same length and time scale of the prediction. For example, the most fundamental predictor of complexation kinetics in aqueous solution is the characteristic water exchange rate, which are well known for the aquo ions and vary by 20 orders of magnitude even for simple trivalent ions. In contrast, for interfacial reactions, it was not even known whether water exchange rates were faster or slower than equivalent metal sites in solution, prohibiting any quantitive understanding of mineral reaction kinetics at the molecular level. Recent advances in synthesis and characterization of materials at nanometer length scales has been able to bridge the gap in scale, and nanometer-sized minerals have given us our first quantitative understanding of elementary reaction rates for fundamental processes involving water and hydroxide exchange reactions. I describe the results of molecular dynamics calculation and experimental measurement of the rates of water, hydroxide, and proton exchange reactions on nanoparticle surfaces. The calculations already show that transition state theory is completely inadequate to understand the rates of even the simplest elementary reactions. Furthermore, the mechanistic implications of rate parameters such as activation volume and activation enthalpy may be different in moving from aquo ions to interfaces. Is a molecular understanding of geochemical processes really needed? One might have asked a biologist at the turn of the century whether studying the structure of proteins would ever

Nanometer-scale oxide thin film transistor with potential for high-density image sensor applications.

PubMed

Jeon, Sanghun; Park, Sungho; Song, Ihun; Hur, Ji-Hyun; Park, Jaechul; Kim, Hojung; Kim, Sunil; Kim, Sangwook; Yin, Huaxiang; Chung, U-In; Lee, Eunha; Kim, Changjung

2011-01-01

The integration of electronically active oxide components onto silicon circuits represents an innovative approach to improving the functionality of novel devices. Like most semiconductor devices, complementary-metal-oxide-semiconductor image sensors (CISs) have physical limitations when progressively scaled down to extremely small dimensions. In this paper, we propose a novel hybrid CIS architecture that is based on the combination of nanometer-scale amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) and a conventional Si photo diode (PD). With this approach, we aim to overcome the loss of quantum efficiency and image quality due to the continuous miniaturization of PDs. Specifically, the a-IGZO TFT with 180 nm gate length is probed to exhibit remarkable performance including low 1/f noise and high output gain, despite fabrication temperatures as low as 200 °C. In particular, excellent device performance is achieved using a double-layer gate dielectric (Al₂O₃/SiO₂) combined with a trapezoidal active region formed by a tailored etching process. A self-aligned top gate structure is adopted to ensure low parasitic capacitance. Lastly, three-dimensional (3D) process simulation tools are employed to optimize the four-pixel CIS structure. The results demonstrate how our stacked hybrid device could be the starting point for new device strategies in image sensor architectures. Furthermore, we expect the proposed approach to be applicable to a wide range of micro- and nanoelectronic devices and systems.

Antitumoral, antihypertensive, antimicrobial, and antioxidant effects of an octanuclear copper(II)-telmisartan complex with an hydrophobic nanometer hole.

PubMed

Islas, María S; Martínez Medina, Juan J; López Tévez, Libertad L; Rojo, Teófilo; Lezama, Luis; Griera Merino, Mercedes; Calleros, Laura; Cortes, María A; Rodriguez Puyol, Manuel; Echeverría, Gustavo A; Piro, Oscar E; Ferrer, Evelina G; Williams, Patricia A M

2014-06-02

A new Cu(II) complex with the antihypertensive drug telmisartan, [Cu8Tlm16]·24H2O (CuTlm), was synthesized and characterized by elemental analysis and electronic, FTIR, Raman and electron paramagnetic resonance spectroscopy. The crystal structure (at 120 K) was solved by X-ray diffraction methods. The octanuclear complex is a hydrate of but otherwise isostructural to the previously reported [Cu8Tlm16] complex. [Cu8Tlm16]·24H2O crystallizes in the tetragonal P4/ncc space group with a = b = 47.335(1), c = 30.894(3) Å, Z = 4 molecules per unit cell giving a macrocyclic ring with a double helical structure. The Cu(II) ions are in a distorted bipyramidal environment with a somewhat twisted square basis, cis-coordinated at their core N2O2 basis to two carboxylate oxygen and two terminal benzimidazole nitrogen atoms. Cu8Tlm16 has a toroidal-like shape with a hydrophobic nanometer hole, and their crystal packing defines nanochannels that extend along the crystal c-axis. Several biological activities of the complex and the parent ligand were examined in vitro. The antioxidant measurements indicate that the complex behaves as a superoxide dismutase mimic with improved superoxide scavenger power as compared with native sartan. The capacity of telmisartan and its copper complex to expand human mesangial cells (previously contracted by angiotensin II treatment) is similar to each other. The antihypertensive effect of the compounds is attributed to the strongest binding affinity to angiotensin II type 1 receptor and not to the antioxidant effects. The cytotoxic activity of the complex and that of its components was determined against lung cancer cell line A549 and three prostate cancer cell lines (LNCaP, PC-3, and DU 145). The complex displays some inhibitory effect on the A549 line and a high viability decrease on the LNCaP (androgen-sensitive) line. From flow cytometric analysis, an apoptotic mechanism was established for the latter cell line. Telmisartan and CuTlm show

Photogrammetric analysis of horizon panoramas: The Pathfinder landing site in Viking orbiter images

USGS Publications Warehouse

Oberst, J.; Jaumann, R.; Zeitler, W.; Hauber, E.; Kuschel, M.; Parker, T.; Golombek, M.; Malin, M.; Soderblom, L.

1999-01-01

Tiepoint measurements, block adjustment techniques, and sunrise/sunset pictures were used to obtain precise pointing data with respect to north for a set of 33 IMP horizon images. Azimuth angles for five prominent topographic features seen at the horizon were measured and correlated with locations of these features in Viking orbiter images. Based on this analysis, the Pathfinder line/sample coordinates in two raw Viking images were determined with approximate errors of 1 pixel, or 40 m. Identification of the Pathfinder location in orbit imagery yields geological context for surface studies of the landing site. Furthermore, the precise determination of coordinates in images together with the known planet-fixed coordinates of the lander make the Pathfinder landing site the most important anchor point in current control point networks of Mars. Copyright 1999 by the American Geophysical Union.

Fabrication of aligned magnetic nanoparticles using tobamoviruses.

PubMed

Kobayashi, Mime; Seki, Munetoshi; Tabata, Hitoshi; Watanabe, Yuichiro; Yamashita, Ichiro

2010-03-10

We used genetically modified tube-shaped tobamoviruses to produce 3 nm aligned magnetic nanoparticles. Amino acid residues facing the central channel of the virus were modified to increase the number of nucleation sites. Energy dispersive X-ray spectroscopy and superconducting quantum interference device analysis suggest that the particles consisted of Co-Pt alloy. The use of tobamovirus mutants is a promising approach to making a variety of components that can be applied to fabricate nanometer-scaled electronic devices.

An analysis of benefits and risk information on pharmaceutical web sites for the treatment of menopause.

PubMed

Charbonneau, Deborah H

2013-09-01

As the Internet is a source of information for many health consumers, there is a need to evaluate the information about prescription drugs provided on pharmaceutical manufacturers' web sites. Using a sample of pharmaceutical manufacturers' web sites for the treatment of menopause, the main objective of this study was to evaluate consumer-oriented information about benefits and risks of prescription drugs for the treatment of menopause provided on pharmaceutical web sites. Pharmaceutical manufacturers' web sites for analysis were identified using a list of U.S. FDA-approved hormone therapies for the treatment of menopause. This study revealed substantial gaps in how benefits and risk information were presented on the web sites. Specifically, information about the benefits was prominent while risk information was incomplete and challenging to find. Further, references to the scientific literature to support claims advertised about prescription drug benefits were not provided. Given the lack of scientific evidence to support claims of benefits and limited disclosure about risks, more information is needed for consumers to be able to weigh the benefits and risks of these treatments for menopause. Overall, these findings provide guidance for evaluating drug information provided on pharmaceutical web sites. © 2013 The author. Health Information and Libraries Journal © 2013 Health Libraries Group.

Computational active site analysis of molecular pathways to improve functional classification of enzymes.

PubMed

Ozyurt, A Sinem; Selby, Thomas L

2008-07-01

This study describes a method to computationally assess the function of homologous enzymes through small molecule binding interaction energy. Three experimentally determined X-ray structures and four enzyme models from ornithine cyclo-deaminase, alanine dehydrogenase, and mu-crystallin were used in combination with nine small molecules to derive a function score (FS) for each enzyme-model combination. While energy values varied for a single molecule-enzyme combination due to differences in the active sites, we observe that the binding energies for the entire pathway were proportional for each set of small molecules investigated. This proportionality of energies for a reaction pathway appears to be dependent on the amino acids in the active site and their direct interactions with the small molecules, which allows a function score (FS) to be calculated to assess the specificity of each enzyme. Potential of mean force (PMF) calculations were used to obtain the energies, and the resulting FS values demonstrate that a measurement of function may be obtained using differences between these PMF values. Additionally, limitations of this method are discussed based on: (a) larger substrates with significant conformational flexibility; (b) low homology enzymes; and (c) open active sites. This method should be useful in accurately predicting specificity for single enzymes that have multiple steps in their reactions and in high throughput computational methods to accurately annotate uncharacterized proteins based on active site interaction analysis. 2008 Wiley-Liss, Inc.

Quantitative determination of occupation sites of trace Co substituted for multiple Fe sites in M-type hexagonal ferrite using statistical beam-rocking TEM-EDXS analysis.

PubMed

Ohtsuka, Masahiro; Muto, Shunsuke; Tatsumi, Kazuyoshi; Kobayashi, Yoshinori; Kawata, Tsunehiro

2016-04-01

The occupation sites and the occupancies of trace dopants in La/Co co-doped Sr-M-type ferrite, SrFe12O19, were quantitatively and precisely determined by beam-rocking energy-dispersive X-ray spectroscopy (EDXS) on the basis of electron-channeling effects. Because the Co atoms, in particular, should be partially substituted for the five crystallographically inequivalent sites, which could be key parameters in improving the magneto-crystalline anisotropy, it is difficult yet intriguing to discover their occupation sites and occupancies without using the methods of large-scale facilities, such as neutron diffraction and synchrotron radiation. In the present study, we tackled this problem by applying an extended statistical atom location by channeling enhanced microanalysis method, using conventional transmission electron microscopy, EDXS and dynamical electron elastic/inelastic scattering theories. The results show that the key occupation sites of Co were the 2a, 4f1 and 12k sites. The quantified occupancies of Co were consistent with those of the previous study, which involved a combination of neutron diffraction and extended X-ray absorption fine structure analysis, as well as energetics considerations based on by first-principles calculations. © The Author 2015. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Selecting landing sites for lunar lander missions using spatial analysis

NASA Astrophysics Data System (ADS)

Djachkova, Maia; Lazarev, Evgeniy

Russian Federal Space Agency (Roscosmos) is planning to launch two spacecrafts to the Moon with lander missions in 2015 and 2017. [1] Here, we present an approach to create a method of landing sites selection. We researched the physical features of the Moon using spatial analysis techniques presented in ArcGIS Desktop Software in accordance with its suitability for automatic landing. Hence we analyzed Russian lunar program and received the technical characteristics of the spacecrafts and scientific goals that they should meet [1]. Thus we identified the criteria of surface suitability for landing. We divided them into two groups: scientific criteria (the hydrogen content of the regolith [2] and day and night sur-face temperature [3]) and safety criteria (surface slopes and roughness, sky view factor, the Earth altitude, presence of polar permanently shadowed regions). In conformity with some investigations it is believed that the south polar region of the Moon is the most promising territory where water ice can be found (finding water ice is the main goal for Russian lunar missions [1]). According to the selected criteria and selected area of research we used remote sensing data from LRO (Lunar Reconnaissance Orbiter) [4] as basic data, because it is the most actual and easily available. The data was processed and analyzed using spatial analysis techniques of ArcGIS Desktop Software, so we created a number of maps depicting the criteria and then combined and overlaid them. As a result of overlay process we received five territories where the landing will be safe and the scientific goals will have being met. It should be noted that our analysis is only the first order assessment and the results cannot be used as actual landing sites for the lunar missions in 2015 and 2017, since a number of factors, which can only be analyzed in a very large scale, was not taken into account. However, an area of researching is narrowed to five territories, what can make the future

Assessment of possible airborne impact from nuclear risk sites - Part II: probabilistic analysis of atmospheric transport patterns in Euro-Arctic region

NASA Astrophysics Data System (ADS)

Mahura, A. G.; Baklanov, A. A.

2003-10-01

The probabilistic analysis of atmospheric transport patterns from most important nuclear risk sites in the Euro-Arctic region is performed employing the methodology developed within the "Arctic Risk" Project of the NARP Programme (Baklanov and Mahura, 2003). The risk sites are the nuclear power plants in the Northwest Russia, Finland, Sweden, Lithuania, United Kingdom, and Germany as well as the Novaya Zemlya test site of Russia. The geographical regions of interest are the Northern and Central European countries and Northwest Russia. In this study, the employed research tools are the trajectory model to calculate a multiyear dataset of forward trajectories that originated over the risk site locations, and a set of statistical methods (including exploratory, cluster, and probability fields analyses) for analysis of trajectory modelling results. The probabilistic analyses of trajectory modelling results for eleven sites are presented as a set of various indicators of the risk sites possible impact on geographical regions and countries of interest. The nuclear risk site possible impact (on a particular geographical region, territory, country, site, etc.) due to atmospheric transport from the site after hypothetical accidental release of radioactivity can be properly estimated based on a combined interpretation of the indicators (simple characteristics, atmospheric transport pathways, airflow and fast transport probability fields, maximum reaching distance and maximum possible impact zone, typical transport time and precipitation factor fields) for different time periods (annual, seasonal, and monthly) for any selected site (both separately for each site or grouped for several sites) in the Euro-Arctic region. Such estimation could be the useful input information for the decision-making process, risk assessment, and planning of emergency response systems for sites of nuclear, chemical, and biological danger.

ANALYSIS OF SURGICAL SITE INFECTIONS IN PEDIATRIC PATIENTS AFTER ORTHOPEDIC SURGERY: A CASE-CONTROL STUDY

PubMed Central

Chagas, Mariana de Queiroz Leite; Costa, Ana Maria Magalhães; Mendes, Pedro Henrique Barros; Gomes, Saint Clair

2017-01-01

ABSTRACT Objectives: To describe the rate of surgical site infections in children undergoing orthopedic surgery in centers of excellence and analyze the patients’ profiles. Methods: Medical records of pediatric patients undergoing orthopedic surgery in the Jamil Haddad National Institute of Traumatology and Orthopedics from January 2012 to December 2013 were analyzed and monitored for one year. Patients diagnosed with surgical site infection were matched with patients without infection by age, date of admission, field of orthopedic surgery and type of surgical procedure. Patient, surgical and follow-up variables were examined. Descriptive, bivariate and correspondence analyses were performed to evaluate the patients’ profiles. Results: 347 surgeries and 10 surgical site infections (2.88%) were identified. There was association of infections with age - odds ratio (OR) 11.5 (confidence interval - 95%CI 1.41-94.9) -, implant - OR 7.3 (95%CI 1.46-36.3) -, preoperative period - OR 9.8 (95%CI 1.83-53.0), and length of hospitalization - OR 20.6 (95%CI 3.7-114.2). The correspondence analysis correlated the infection and preoperative period, weight, weight Z-score, age, implant, type of surgical procedure, and length of hospitalization. Average time to diagnosis of infection occurred 26.5±111.46 days after surgery. Conclusions: The rate of surgical site infection was 2.88%, while higher in children over 24 months of age who underwent surgical implant procedures and had longer preoperative periods and lengths of hospitalization. This study identified variables for the epidemiological surveillance of these events in children. Available databases and appropriate analysis methods are essential to monitor and improve the quality of care offered to the pediatric population. PMID:28977312

Directional analysis of CO2 persistence at a rural site.

PubMed

Pérez, Isidro A; Sánchez, M Luisa; García, M Ángeles; Paredes, Vanessa

2011-09-01

Conditional probability was used to establish persistence of CO(2) concentrations at a rural site. Measurements extended over three years and were performed with a CO(2) continuous monitor and a sodar. Concentrations in the usual range at this site were proposed as the truncation level to calculate conditional probability, allowing us to determine the extent of CO(2) sequences. Extension of episodes may be inferred from these values. Persistence of wind directions revealed two groups of sectors, one with a persistence of about 16 h and another of about 9 h. Cumulative distribution of CO(2) was calculated in each wind sector and three groups, associated with different concentration origins, were established. One group was linked to transport and local sources, another to the rural environment, and a third to transport of clean air masses. Daily evolution of concentrations revealed major differences during the night and monthly analysis allowed us to associate group 1 with the vegetation cycle and group 3 with wind speed from December to April. Persistence of concentrations was obtained, and group 3 values were lower for concentrations above the truncation level, whereas persistence of groups 1 and 2 was similar. However, group 3 persistence was, in general, between group 1 and 2 persistence for concentrations below the truncation level. Copyright © 2011 Elsevier B.V. All rights reserved.

Privacy and health in the information age: a content analysis of health web site privacy policy statements.

PubMed

Rains, Stephen A; Bosch, Leslie A

2009-07-01