Micro- and Nano-Scale Fabrication of Fluorinated Polymers by Direct Etching Using Focused Ion Beam

NASA Astrophysics Data System (ADS)

Naoyuki Fukutake,; Nozomi Miyoshi,; Yuya Takasawa,; Tatsuya Urakawa,; Tomoko Gowa,; Kazumasa Okamoto,; Akihiro Oshima,; Seiichi Tagawa,; Masakazu Washio,

2010-06-01

Micro- and nano-scale fabrications of various fluorinated polymers were demonstrated by direct maskless etching using a focused ion beam (FIB). The etching rates of perfluorinated polymers, such as poly(tetrafluoroethylene) (PTFE), poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP), poly(tetrafluoroethylene-co-perfluoroalkoxyvinylether) (PFA), were about 500-1000 times higher than those of partially fluorinated polymers, such as poly(tetrafluoroethylene-co-ethylene) (ETFE) and poly(vinilydene-fluoride) (PVdF). Controlled high quality and high aspect-ratio nanostructures of spin-coated cross-linked PTFE were obtained without solid debris. The height and diameter of the fibers were about 1.5 μm and 90 nm, respectively. Their aspect ratio was about 17.

Structure and tribological behavior of Pb-Ti/MoS2 nanoscaled multilayer films deposited by magnetron sputtering method

NASA Astrophysics Data System (ADS)

Li, Hao; Xie, Mingling; Zhang, Guangan; Fan, Xiaoqiang; Li, Xia; Zhu, Minhao; Wang, Liping

2018-03-01

The Pb-Ti/MoS2 nanoscaled multilayer films with different bilayer period were deposited by unbalanced magnetron sputtering system. The morphology, microstructure, mechanical and tribological properties of the films were investigated. It was found that the film changed from multilayer structure to composite structure as the bilayer period decreased from 25 nm to 6 nm, due to the diffusion effect. The multilayer film showed a pronounced (002) diffraction peak, the growth of the MoS2 platelets below the interface were affected by Pb and Ti, and the c-axis of MoS2 platelets were inclined to the substrate at an angle of -30° to 30°. The hardness of the film ranged from 5.9 to 7.2 GPa depending on the bilayer period. The tribological behavior of the films was performed under vacuum, and the friction coefficient were typically below 0.25. Furthermore, the nanoscale multilayer film with a bilayer period of 20 nm exhibits much better mechanical and tribological properties than pure MoS2. The result indicates that the nanoscale multilayer is a design methodology for developing high basal plane oriented and vacuum solid lubricating MoS2 based materials.

Nano-electromechanical switch-CMOS hybrid technology and its applications.

PubMed

Lee, B H; Hwang, H J; Cho, C H; Lim, S K; Lee, S Y; Hwang, H

2011-01-01

Si-based CMOS technology is facing a serious challenge in terms of power consumption and variability. The increasing costs associated with physical scaling have motivated a search for alternative approaches. Hybridization of nano-electromechanical (NEM)-switch and Si-based CMOS devices has shown a theoretical feasibility for power management, but a huge technical gap must be bridged before a nanoscale NEM switch can be realized due to insufficient material development and the limited understanding of its reliability characteristics. These authors propose the use of a multilayer graphene as a nanoscale cantilever material for a nanoscale NEM switchwith dimensions comparable to those of the state-of-the-art Si-based CMOS devices. The optimal thickness for the multilayer graphene (about five layers) is suggested based on an analytical model. Multilayer graphene can provide the highest Young's modulus among the known electrode materials and a yielding strength that allows more than 15% bending. Further research on material screening and device integration is needed, however, to realize the promises of the hybridization of NEM-switch and Si-based CMOS devices.

Deformation mechanism of CrN/nitriding coated steel in wear and nano-scratch experiments under heavy loading conditions

NASA Astrophysics Data System (ADS)

Wang, Yongguang; Chen, Yao; Zhao, Dong; Lu, Xiaolong; Liu, Weiwei; Qi, Fei; Chen, Yang

2018-07-01

CrN coatings are widely used to protect metals from wear in industrial engineering. However, fundamental deformation mechanism of these coatings under heavy loading conditions remains elusive. In this paper, multilayered hard coatings with a CrN matrix and a supporting layer were developed by means of the hybrid deposition process combined with PVD and ionicnitriding. The tribological behavior of coatings with and without ionicnitriding were investigated by a pin-on-disk arrangement under heavy loading conditions. In addition, the deformation mechanism of the multilayered hard coatings was studied by nano-scratch experiment with ramp load model, which has not been discussed previously. It was found that the deformation process of coatings could be divided into three regimes based on the evolution of frictional coefficient. The insertion of nitriding films leads to the further increase in frictional resistance owing to the elastic-plastic deformation. The results and analysis reveal some insights into the coating design for multilayered hard coatings with the consideration of deformation mechanisms.

Nanoscale deformation mechanism of TiC/a-C nanocomposite thin films

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

Chen, C. Q.; Pei, Y. T.; Shaha, K. P.

2009-06-01

This paper concentrates on the deformation behavior of amorphous diamondlike carbon composite materials. Combined nanoindentation and ex situ cross-sectional transmission electron microscopy investigations are carried out on TiC/a-C nanocomposite films, with and without multilayered structures deposited by pulse dc magnetron sputtering. It is shown that by controlling the distribution of nanocrystallites forming nanoscale multilayers, the system can be used as a 'microstructural ruler' that is able to distinguish various deformation patterns, which can be hardly detected otherwise in a homogeneous structure. It is shown that rearrangement of nanocrystallites and displacement of a-C matrix occur at length scales from tens ofmore » nanometer down to 1 nm. At submicrometer scale homogeneous nucleation of multiple shear bands has been observed within the nanocomposites. The multilayered structure in the TiC/a-C nanocomposite film contributes to an enhanced toughness.« less

Enhanced Corrosion Resistance of PVD-CrN Coatings by ALD Sealing Layers

NASA Astrophysics Data System (ADS)

Wan; Zhang, Teng Fei; Ding, Ji Cheng; Kim, Chang-Min; Park, So-Won; Yang, Yang; Kim, Kwang-Ho; Kwon, Se-Hun

2017-04-01

Multilayered hard coatings with a CrN matrix and an Al2O3, TiO2, or nanolaminate-Al2O3/TiO2 sealing layer were designed by a hybrid deposition process combined with physical vapor deposition (PVD) and atomic layer deposition (ALD). The strategy was to utilize ALD thin films as pinhole-free barriers to seal the intrinsic defects to protect the CrN matrix. The influences of the different sealing layers added in the coatings on the microstructure, surface roughness, and corrosion behaviors were investigated. The results indicated that the sealing layer added by ALD significantly decreased the average grain size and improved the corrosion resistance of the CrN coatings. The insertion of the nanolaminate-Al2O3/TiO2 sealing layers resulted in a further increase in corrosion resistance, which was attributed to the synergistic effect of Al2O3 and TiO2, both acting as excellent passivation barriers to the diffusion of corrosive substances.

Identifying Deformation and Strain Hardening Behaviors of Nanoscale Metallic Multilayers Through Nano-wear Testing

DOE PAGES

Economy, David Ross; Mara, Nathan A.; Schoeppner, R.; ...

2016-01-13

In complex loading conditions (e.g. sliding contact), mechanical properties, such as strain hardening and initial hardness, will dictate the long-term performance of materials systems. With this in mind, the strain hardening behaviors of Cu/Nb nanoscale metallic multilayer systems were examined by performing nanoindentation tests within nanoscratch wear boxes and undeformed, as-deposited regions. Both the architecture and substrate influence were examined by utilizing three different individual layer thicknesses (2, 20, and 100 nm) and two total film thicknesses (1 and 10 μm). After nano-wear deformation, multilayer systems with thinner layers showed less volume loss as measured by laser scanning microscopy. Additionally,more » the hardness of the deformed regions significantly rose with respect to the as-deposited measurements, which further increased with greater wear loads. Strain hardening exponents for multilayers with thinner layers (2 and 20 nm, n ≈ 0.018 and n ≈ 0.022 respectively) were less than was determined for 100 nm systems (n ≈ 0.041). These results suggest that singledislocation based deformation mechanisms observed for the thinner systems limit the extent of achievable strain hardening. This conclusion indicates that impacts of both architecture strengthening and strain hardening must be considered to accurately predict multilayer performance during sliding contact across varying length scales.« less

A novel evaluation strategy for fatigue reliability of flexible nanoscale films

NASA Astrophysics Data System (ADS)

Zheng, Si-Xue; Luo, Xue-Mei; Wang, Dong; Zhang, Guang-Ping

2018-03-01

In order to evaluate fatigue reliability of nanoscale metal films on flexible substrates, here we proposed an effective evaluation way to obtain critical fatigue cracking strain based on the direct observation of fatigue damage sites through conventional dynamic bending testing technique. By this method, fatigue properties and damage behaviors of 930 nm-thick Au films and 600 nm-thick Mo-W multilayers with individual layer thickness 100 nm on flexible polyimide substrates were investigated. Coffin-Manson relationship between the fatigue life and the applied strain range was obtained for the Au films and Mo-W multilayers. The characterization of fatigue damage behaviors verifies the feasibility of this method, which seems easier and more effective comparing with the other testing methods.

Multilayered metal-insulator nanocavities: toward tunable multi-resonance nano-devices for integrated optics

NASA Astrophysics Data System (ADS)

Song, Junyeob; Zhou, Wei

2017-02-01

Plasmonic nanocavities can control light flows and enhance light-mater interactions at subwavelength scale, and thus can potentially be used as nanoscale components in integrated optics systems either for passive optical coupling, or for active optical modulation and emission. In this work, we investigated a new type of multilayered metal-insulator optical nanocavities that can support multiple localized plasmon resonances with ultra-small mode volumes. The total number of resonance peaks and their resonance wavelengths can be freely and accurately controlled by simple geometric design rules. Multi-resonance plasmonic nanocavities can serve as a nanoscale wavelength-multiplexed optical components in integrated optics systems, such as optical couplers, light emitters, nanolasers, optical sensors, and optical modulators.

Tunable self-organization of nanocomposite multilayers

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

Chen, C. Q.; Pei, Y. T.; Shaha, K. P.

In this letter we report the controlled growth and microstructural evolution of self-assembled nanocomposite multilayers that are induced by surface ion-impingement. The nanoscale structures together with chemical composition, especially at the growing front, have been investigated with high-resolution transmission electron microscopy. Concurrent ion impingement of growing films produces an amorphous capping layer 3 nm in thickness where spatially modulated phase separation is initiated. It is shown that the modulation of multilayers as controlled by the self-organization of nanocrystallites below the capping layer, can be tuned through the entire film.

Soft X-Ray Optics by Pulsed Laser Deposition

NASA Technical Reports Server (NTRS)

Fernandez, Felix E.

1996-01-01

Mo/Si and C/Co multilayers for soft x-ray optics were designed for spectral regions of interest in possible applications. Fabrication was effected by Pulsed Laser Deposition using Nd:YAG (355 nm) or excimer (248 nm) lasers in order to evaluate the suitability of this technique. Results for Mo/Si structures were not considered satisfactory due mainly to problems with particulate production and target surface modification during Si ablation. These problems may be alleviated by a two-wavelength approach, using separate lasers for each target. Results for C/Co multilayers are much more encouraging, since indication of good layering was observed for extremely thin layers. We expect to continue investigating this possibility. In order to compete with traditional PVD techniques, it is necessary to achieve film coverage uniformity over large enough areas. It was shown that this is feasible, and novel means of achieving it were devised.

Magnetic and electrical properties of FeSi/FeSi-ZrO 2 multilayers prepared by EB-PVD

NASA Astrophysics Data System (ADS)

Bi, Xiaofang; Lan, Weihua; Ou, Shengquan; Gong, Shengkai; Xu, Huibin

2003-04-01

FeSi/FeSi-ZrO 2 and FeSi/ZrO 2 multilayer materials were prepared by electron beam physical vapor deposition with the FeSi-ZrO 2 layer thickness about 0.6 μm, and their magnetic and electrical properties were studied as a function of FeSi layer thickness. With increasing FeSi layer thickness from 0.3 to 3 μm, the coercivity decreased from 0.92 to 0.31 kA/m and the saturation magnetization changed from 164 to 186 emu/g. The effect of the layer number on the magnetic properties was discussed in terms of interfacial mixing and oxidation. It was also discovered that the magnetic properties of the multilayer materials were affected by the spacer material, exhibiting higher saturation magnetization and lower coercivity for the FeSi/FeSi-ZrO 2 than those for the FeSi/ZrO 2 with the same individual layer thicknesses. This behavior could be explained by the weaker magnetic interaction between FeSi layers separated by the non-magnetic ZrO 2 layer. Furthermore, the electrical resistivity changed from 1850 to 1250 μΩ cm for the multilayer materials for the FeSi thickness increasing from 0.30 to 3 μm.

Nanoscale Surface Modification of Polycrystalline Tin Sulphide Films during Plasma Treatment

NASA Astrophysics Data System (ADS)

Zimin, S. P.; Gorlachev, E. S.; Dubov, G. A.; Amirov, I. I.; Naumov, V. V.; Gremenok, V. F.; Ivanov, V. A.; Seidi, H. G.

2013-05-01

In this paper, we present a comparative research of the nanoscale modification of the surface morphology of polycrystalline SnS films on glass substrates with two different preferred growth orientations processed in inductively coupled argon plasma. We report a new effect of polycrystalline SnS film surface smoothing during plasma treatment, which can be advantageous for the fabrication of multilayer solar cell devices with SnS absorption layers.

Oleophobic optical coating deposited by magnetron PVD

NASA Astrophysics Data System (ADS)

Bernt, D.; Ponomarenko, V.; Pisarev, A.

2016-09-01

Thin oxinitride films of Zn-Sn-O-N and Si-Al-O-N were deposited on glass by reactive magnetron sputtering at various nitrogen-to-oxygen ratios. Nitrogen added to oxygen led to decrease of the surface roughness and increase of oleophobic properties studied by the oil-drop test. The best oleophobity was obtained for Zn-Sn-O-N oxinitride at Zn:Sn=1:1 and N:O=1:2. Improved oleophobic properties were also demonstrated if the oxinitride film was deposited on top of the multilayer coating as the final step in the industrial cycle of production of energy efficient glass.

Methods to improve the PVD coatability of brass by using diffusion barriers

NASA Astrophysics Data System (ADS)

Langer, Bernd

Previous work involving PVD coatings on brass has used a combination of multilayers consisting of electroplated films like nickel or chromium and deposited decorative PVD coatings like TiN, TiAIN or ZrN systems. The disadvantages of these systems are the combination of wet electrochemistry and high tech vacuum processes. Furthermore the allergic reaction to nickel and the toxic nature of Cr(VI) must be considered.There is a need for intermediate layers to 'seal-off the brass in order to avoid the evaporation of zinc in vacuum using a diffusion barrier. Furthermore the intermediate layers are required to act as a corrosion barrier.This thesis reports on the development of PVD coatings on heat sensitive brass substrate materials utilising ABS technology with Al, CuAl8 and Nb targets as vapour sources.The brass pretreatment includes careful grinding, polishing and cleaning steps as well as steered arc metal ion etching using the above target materials. The coatings are produced at temperatures between 100 and 250°C in the unbalanced magnetron mode, including layers made from Al, Al-Nb, CuA18, CuAl8-Nb and Nb.Scratch adhesion and Rockwell indentation tests are found not to be directly applicable to the system of soft brass and ductile coating(s). Therefore a new classification for both scratch and indentation tests was defined. The best adhesion was shown by the CuA18 coatings on brass. Corrosion tests showed good results for the Al coatings and poor results for the pure Nb coatings directly applied on brass. The best corrosion result was obtained with a CuAl8-Nb layer system. This layer system also offers very good barrier behaviour concerning Zn diffusion.Other investigations like Glow Discharge Optical Emission Spectroscopy (GDOES), Scanning Electron Microscopy (SEM) imaging, Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD) were undertaken to characterise the new coating systems for brass.

Characterization of Mo/Si multilayer growth on stepped topographies

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

Boogaard, A. J. R. vcan den; Louis, E.; Zoethout, E.

2011-08-31

Mo/Si multilayer mirrors with nanoscale bilayer thicknesses have been deposited on stepped substrate topographies, using various deposition angles. The multilayer morphology at the stepedge region was studied by cross section transmission electron microscopy. A transition from a continuous- to columnar layer morphology is observed near the step-edge, as a function of the local angle of incidence of the deposition flux. Taking into account the corresponding kinetics and anisotropy in layer growth, a continuum model has been developed to give a detailed description of the height profiles of the individual continuous layers. Complementary optical characterization of the multilayer system using amore » microscope operating in the extreme ultraviolet wavelength range, revealed that the influence of the step-edge on the planar multilayer structure is restricted to a region within 300 nm from the step-edge.« less

Fabrication and characterization of one-dimensional multilayer gratings for nanoscale microscope calibration

NASA Astrophysics Data System (ADS)

Wang, Xingrui; Zhao, Yang; Liu, Jie; Chen, Jie; Li, Tongbao; Cheng, Xinbin

2016-09-01

One-dimensional multilayer gratings were prepared by four steps. A periodic Si/SiO2 multilayer was firstly deposited on Si substrate using a magnetron sputtering coating process. Then, the multilayer was been bonded and split into small pieces by diamond wire cutting. The side-wall of the cut sample was subsequently grinded and polished until the surface roughness was less than 1nm. Finally, the SiO2 layers were selective etched using hydrofluoric acid to form the grating structure. In the above steps, special attentions were given to optimize the etching processes to achieve a uniform and smooth grating pattern. Transmission electron microscope (TEM) was used to characterize the multilayer gratings. The pitch size of the grating was evaluated by an offline image analysis algorithm and optimized processes are discussed.

Multi-layer thin-film electrolytes for metal supported solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Haydn, Markus; Ortner, Kai; Franco, Thomas; Uhlenbruck, Sven; Menzler, Norbert H.; Stöver, Detlev; Bräuer, Günter; Venskutonis, Andreas; Sigl, Lorenz S.; Buchkremer, Hans-Peter; Vaßen, Robert

2014-06-01

A key to the development of metal-supported solid oxide fuel cells (MSCs) is the manufacturing of gas-tight thin-film electrolytes, which separate the cathode from the anode. This paper focuses the electrolyte manufacturing on the basis of 8YSZ (8 mol.-% Y2O3 stabilized ZrO2). The electrolyte layers are applied by a physical vapor deposition (PVD) gas flow sputtering (GFS) process. The gas-tightness of the electrolyte is significantly improved when sequential oxidic and metallic thin-film multi-layers are deposited, which interrupt the columnar grain structure of single-layer electrolytes. Such electrolytes with two or eight oxide/metal layers and a total thickness of about 4 μm obtain leakage rates of less than 3 × 10-4 hPa dm3 s-1 cm-2 (Δp: 100 hPa) at room temperature and therefore fulfill the gas tightness requirements. They are also highly tolerant with respect to surface flaws and particulate impurities which can be present on the graded anode underground. MSC cell tests with double-layer and multilayer electrolytes feature high power densities more than 1.4 W cm-2 at 850 °C and underline the high potential of MSC cells.

Hierarchical adaptive nanostructured PVD coatings for extreme tribological applications: the quest for nonequilibrium states and emergent behavior.

PubMed

Fox-Rabinovich, German S; Yamamoto, Kenji; Beake, Ben D; Gershman, Iosif S; Kovalev, Anatoly I; Veldhuis, Stephen C; Aguirre, Myriam H; Dosbaeva, Goulnara; Endrino, Jose L

2012-08-01

Adaptive wear-resistant coatings produced by physical vapor deposition (PVD) are a relatively new generation of coatings which are attracting attention in the development of nanostructured materials for extreme tribological applications. An excellent example of such extreme operating conditions is high performance machining of hard-to-cut materials. The adaptive characteristics of such coatings develop fully during interaction with the severe environment. Modern adaptive coatings could be regarded as hierarchical surface-engineered nanostructural materials. They exhibit dynamic hierarchy on two major structural scales: (a) nanoscale surface layers of protective tribofilms generated during friction and (b) an underlying nano/microscaled layer. The tribofilms are responsible for some critical nanoscale effects that strongly impact the wear resistance of adaptive coatings. A new direction in nanomaterial research is discussed: compositional and microstructural optimization of the dynamically regenerating nanoscaled tribofilms on the surface of the adaptive coatings during friction. In this review we demonstrate the correlation between the microstructure, physical, chemical and micromechanical properties of hard coatings in their dynamic interaction (adaptation) with environment and the involvement of complex natural processes associated with self-organization during friction. Major physical, chemical and mechanical characteristics of the adaptive coating, which play a significant role in its operating properties, such as enhanced mass transfer, and the ability of the layer to provide dissipation and accumulation of frictional energy during operation are presented as well. Strategies for adaptive nanostructural coating design that enhance beneficial natural processes are outlined. The coatings exhibit emergent behavior during operation when their improved features work as a whole. In this way, as higher-ordered systems, they achieve multifunctionality and high wear resistance under extreme tribological conditions.

Hierarchical adaptive nanostructured PVD coatings for extreme tribological applications: the quest for nonequilibrium states and emergent behavior

PubMed Central

Fox-Rabinovich, German S; Yamamoto, Kenji; Beake, Ben D; Gershman, Iosif S; Kovalev, Anatoly I; Veldhuis, Stephen C; Aguirre, Myriam H.; Dosbaeva, Goulnara; Endrino, Jose L

2012-01-01

Adaptive wear-resistant coatings produced by physical vapor deposition (PVD) are a relatively new generation of coatings which are attracting attention in the development of nanostructured materials for extreme tribological applications. An excellent example of such extreme operating conditions is high performance machining of hard-to-cut materials. The adaptive characteristics of such coatings develop fully during interaction with the severe environment. Modern adaptive coatings could be regarded as hierarchical surface-engineered nanostructural materials. They exhibit dynamic hierarchy on two major structural scales: (a) nanoscale surface layers of protective tribofilms generated during friction and (b) an underlying nano/microscaled layer. The tribofilms are responsible for some critical nanoscale effects that strongly impact the wear resistance of adaptive coatings. A new direction in nanomaterial research is discussed: compositional and microstructural optimization of the dynamically regenerating nanoscaled tribofilms on the surface of the adaptive coatings during friction. In this review we demonstrate the correlation between the microstructure, physical, chemical and micromechanical properties of hard coatings in their dynamic interaction (adaptation) with environment and the involvement of complex natural processes associated with self-organization during friction. Major physical, chemical and mechanical characteristics of the adaptive coating, which play a significant role in its operating properties, such as enhanced mass transfer, and the ability of the layer to provide dissipation and accumulation of frictional energy during operation are presented as well. Strategies for adaptive nanostructural coating design that enhance beneficial natural processes are outlined. The coatings exhibit emergent behavior during operation when their improved features work as a whole. In this way, as higher-ordered systems, they achieve multifunctionality and high wear resistance under extreme tribological conditions. PMID:27877499

Multi-layer micro/nanofluid devices with bio-nanovalves

DOEpatents

Li, Hao; Ocola, Leonidas E.; Auciello, Orlando H.; Firestone, Millicent A.

2013-01-01

A user-friendly multi-layer micro/nanofluidic flow device and micro/nano fabrication process are provided for numerous uses. The multi-layer micro/nanofluidic flow device can comprise: a substrate, such as indium tin oxide coated glass (ITO glass); a conductive layer of ferroelectric material, preferably comprising a PZT layer of lead zirconate titanate (PZT) positioned on the substrate; electrodes connected to the conductive layer; a nanofluidics layer positioned on the conductive layer and defining nanochannels; a microfluidics layer positioned upon the nanofluidics layer and defining microchannels; and biomolecular nanovalves providing bio-nanovalves which are moveable from a closed position to an open position to control fluid flow at a nanoscale.

Toughening mechanisms in bioinspired multilayered materials.

PubMed

Askarinejad, Sina; Rahbar, Nima

2015-01-06

Outstanding mechanical properties of biological multilayered materials are strongly influenced by nanoscale features in their structure. In this study, mechanical behaviour and toughening mechanisms of abalone nacre-inspired multilayered materials are explored. In nacre's structure, the organic matrix, pillars and the roughness of the aragonite platelets play important roles in its overall mechanical performance. A micromechanical model for multilayered biological materials is proposed to simulate their mechanical deformation and toughening mechanisms. The fundamental hypothesis of the model is the inclusion of nanoscale pillars with near theoretical strength (σth ~ E/30). It is also assumed that pillars and asperities confine the organic matrix to the proximity of the platelets, and, hence, increase their stiffness, since it has been previously shown that the organic matrix behaves more stiffly in the proximity of mineral platelets. The modelling results are in excellent agreement with the available experimental data for abalone nacre. The results demonstrate that the aragonite platelets, pillars and organic matrix synergistically affect the stiffness of nacre, and the pillars significantly contribute to the mechanical performance of nacre. It is also shown that the roughness induced interactions between the organic matrix and aragonite platelet, represented in the model by asperity elements, play a key role in strength and toughness of abalone nacre. The highly nonlinear behaviour of the proposed multilayered material is the result of distributed deformation in the nacre-like structure due to the existence of nano-asperities and nanopillars with near theoretical strength. Finally, tensile toughness is studied as a function of the components in the microstructure of nacre.

Toughening mechanisms in bioinspired multilayered materials

PubMed Central

Askarinejad, Sina; Rahbar, Nima

2015-01-01

Outstanding mechanical properties of biological multilayered materials are strongly influenced by nanoscale features in their structure. In this study, mechanical behaviour and toughening mechanisms of abalone nacre-inspired multilayered materials are explored. In nacre's structure, the organic matrix, pillars and the roughness of the aragonite platelets play important roles in its overall mechanical performance. A micromechanical model for multilayered biological materials is proposed to simulate their mechanical deformation and toughening mechanisms. The fundamental hypothesis of the model is the inclusion of nanoscale pillars with near theoretical strength (σth ~ E/30). It is also assumed that pillars and asperities confine the organic matrix to the proximity of the platelets, and, hence, increase their stiffness, since it has been previously shown that the organic matrix behaves more stiffly in the proximity of mineral platelets. The modelling results are in excellent agreement with the available experimental data for abalone nacre. The results demonstrate that the aragonite platelets, pillars and organic matrix synergistically affect the stiffness of nacre, and the pillars significantly contribute to the mechanical performance of nacre. It is also shown that the roughness induced interactions between the organic matrix and aragonite platelet, represented in the model by asperity elements, play a key role in strength and toughness of abalone nacre. The highly nonlinear behaviour of the proposed multilayered material is the result of distributed deformation in the nacre-like structure due to the existence of nano-asperities and nanopillars with near theoretical strength. Finally, tensile toughness is studied as a function of the components in the microstructure of nacre. PMID:25551150

The mechanical behavior of nanoscale metallic multilayers: A survey

NASA Astrophysics Data System (ADS)

Zhou, Q.; Xie, J. Y.; Wang, F.; Huang, P.; Xu, K. W.; Lu, T. J.

2015-06-01

The mechanical behavior of nanoscale metallic multilayers (NMMs) has attracted much attention from both scientific and practical views. Compared with their monolithic counterparts, the large number of interfaces existing in the NMMs dictates the unique behavior of this special class of structural composite materials. While there have been a number of reviews on the mechanical mechanism of microlaminates, the rapid development of nanotechnology brought a pressing need for an overview focusing exclusively on a property-based definition of the NMMs, especially their size-dependent microstructure and mechanical performance. This article attempts to provide a comprehensive and up-to-date review on the microstructure, mechanical property and plastic deformation physics of NMMs. We hope this review could accomplish two purposes: (1) introducing the basic concepts of scaling and dimensional analysis to scientists and engineers working on NMM systems, and (2) providing a better understanding of interface behavior and the exceptional qualities the interfaces in NMMs display at atomic scale.

Q-factor control of multilayer micromembrane using PZT composite material

NASA Astrophysics Data System (ADS)

Čekas, Elingas; Janušas, Giedrius; Palevicius, Arvydas; Janušas, Tomas; Ciganas, Justas

2018-02-01

Cantilever and membrane based sensors, which are capable of providing accurate detection of target analytes have been always an important research topic of medical diagnostics, food testing, and environmental monitoring fields. Here, the mechanical detection is achieved by micro- and nano-scale cantilevers for stress sensing and mass sensing, or micro- and nano-scale plates or membranes. High sensitivity is a major issue for the active element and it could be achieved via increased Q-factor. The ability to control the Q factor expands the range of application of the device and allows to achieve more accurate results. The aim of this paper is to investigate the mechanical and electrical properties, as well as, the ability to control the Q factor of the membrane with PZT nanocomposite. This multilayered membrane was formatted using the n-type <100> silicon substrate by implementing the Low Pressure Chemical Vapor Deposition (LPCVD), photolithography by using photomask with defined dimensions, deep etching, and e-beam evaporation techniques. Dynamic and electrical characteristics of the membrane were numerically investigated using COMSOL Multiphysics software. The use of the multilayered membrane can range from simple monitoring of particles concentration in a closed environment to inspecting glucose levels in human fluids (blood, tears, sweat, etc.).

The possibility of multi-layer nanofabrication via atomic force microscope-based pulse electrochemical nanopatterning

NASA Astrophysics Data System (ADS)

Kim, Uk Su; Morita, Noboru; Lee, Deug Woo; Jun, Martin; Park, Jeong Woo

2017-05-01

Pulse electrochemical nanopatterning, a non-contact scanning probe lithography process using ultrashort voltage pulses, is based primarily on an electrochemical machining process using localized electrochemical oxidation between a sharp tool tip and the sample surface. In this study, nanoscale oxide patterns were formed on silicon Si (100) wafer surfaces via electrochemical surface nanopatterning, by supplying external pulsed currents through non-contact atomic force microscopy. Nanoscale oxide width and height were controlled by modulating the applied pulse duration. Additionally, protruding nanoscale oxides were removed completely by simple chemical etching, showing a depressed pattern on the sample substrate surface. Nanoscale two-dimensional oxides, prepared by a localized electrochemical reaction, can be defined easily by controlling physical and electrical variables, before proceeding further to a layer-by-layer nanofabrication process.

Prediction of the properties of PVD/CVD coatings with the use of FEM analysis

NASA Astrophysics Data System (ADS)

Śliwa, Agata; Mikuła, Jarosław; Gołombek, Klaudiusz; Tański, Tomasz; Kwaśny, Waldemar; Bonek, Mirosław; Brytan, Zbigniew

2016-12-01

The aim of this paper is to present the results of the prediction of the properties of PVD/CVD coatings with the use of finite element method (FEM) analysis. The possibility of employing the FEM in the evaluation of stress distribution in multilayer Ti/Ti(C,N)/CrN, Ti/Ti(C,N)/(Ti,Al)N, Ti/(Ti,Si)N/(Ti,Si)N, and Ti/DLC/DLC coatings by taking into account their deposition conditions on magnesium alloys has been discussed in the paper. The difference in internal stresses in the zone between the coating and the substrate is caused by, first of all, the difference between the mechanical and thermal properties of the substrate and the coating, and also by the structural changes that occur in these materials during the fabrication process, especially during the cooling process following PVD and CVD treatment. The experimental values of stresses were determined based on X-ray diffraction patterns that correspond to the modelled values, which in turn can be used to confirm the correctness of the accepted mathematical model for testing the problem. An FEM model was established for the purpose of building a computer simulation of the internal stresses in the coatings. The accuracy of the FEM model was verified by comparing the results of the computer simulation of the stresses with experimental results. A computer simulation of the stresses was carried out in the ANSYS environment using the FEM method. Structure observations, chemical composition measurements, and mechanical property characterisations of the investigated materials has been carried out to give a background for the discussion of the results that were recorded during the modelling process.

Nanoscale multilayer Me-graphite coatings grown by combined steered cathodic arc/unbalanced magnetron sputtering

NASA Astrophysics Data System (ADS)

Kok, Yin Nan

Low friction, nanoscale multilayer carbon/chromium (C/Cr) coatings were successfully deposited by the combined steered cathodic arc/unbalanced magnetron sputtering technique (also known as Arc Bond Sputtering or ABS) using a Hauzer HTC 1000-4 PVD coater. The work described in this thesis has been directed towards understanding the effect of ion irradiation on the composition, microstructure, and functional properties of C/Cr coatings. This has been achieved by varying the bias voltage, U[B], over a wide range between -65 V and -550 V. C/Cr coatings were deposited in three major steps: (i) Cr+ ion etching using a steered cathodic arc discharge at a substrate bias voltage of -1200 V, (ii) deposition of a 0.25 mum thick CrN base layer by reactive unbalanced magnetron sputtering to enhance the adhesion, and (iii) deposition of C/Cr coatings by unbalanced magnetron sputtering from three graphite targets and one chromium target at 260°C. The coatings were deposited at different bias voltages (U[B]) from -65 V to -550 V in a non-reactive Ar atmosphere.C/Cr coatings exhibit excellent adhesion (critical load, L[C] > 70 N), with hardness ranging from 6.8 to 25.1 GPa depending on the bias voltage. The friction coefficient of C/Cr coatings was found to reduce from 0.22 to 0.16 when the bias voltage was increased from U[B] = -65 to -95 V. The relevance of C/Cr coatings for actual practical applications was demonstrated using dry high-speed milling trials on automotive aluminium alloy (Al-Si8Cu3Fe). The results showed that C/Cr coated cemented carbide ball-nose end mills prepared at U[B] = -95 V (70 at.% C, 30 at.% Cr) enhance the tool performance and the tool life compared to the uncoated tools by a factor of two, suggesting the potential for use in dry high-speed machining of "sticky" alloys such as aluminum. Different film morphologies were observed in the investigated bias voltage range between U[B] = -65 and -550 V using XTEM. With increasing bias voltage from U[B] = -65 to -95 V, the structure changed from columnar, with carbon accumulated at the column boundaries, to a dense structure which comprised randomly distributed onionlike carbon clusters. A novel nanostructure was observed within this bias voltage range, in which the basic nano-lamellae obtained as a result of substrate rotation in front of the C and Cr targets were modified by an ion-irradiation induced nanocolumnar structure. Further increases in the bias voltage to U[B] = -350 V and U[B] = -450 V led to segregation and self-organisation of the carbon atoms induced by the high energy ion bombardment and, finally, to the formation of a new type of self-organised multilayer structure. A coating growth model accounting for the influence of ion bombardment on the growing C/Cr film was introduced to explain the phase separation and formation of the selforganised layered nanostructure.A novel experimental set-up for the investigation of tribocorrosion was built based on a modification of the conventional Scanning Reference Electrode Technique (SRET). The device comprises a ball on rotating cylinder contact configuration combined with a SRET electrochemical device. This combination may contribute significantly to the understanding of wear-corrosion synergism.

Spectral tailoring of nanoscale EUV and soft x-ray multilayer optics

NASA Astrophysics Data System (ADS)

Huang, Qiushi; Medvedev, Viacheslav; van de Kruijs, Robbert; Yakshin, Andrey; Louis, Eric; Bijkerk, Fred

2017-03-01

Extreme ultraviolet and soft X-ray (XUV) multilayer optics have experienced significant development over the past few years, particularly on controlling the spectral characteristics of light for advanced applications like EUV photolithography, space observation, and accelerator- or lab-based XUV experiments. Both planar and three dimensional multilayer structures have been developed to tailor the spectral response in a wide wavelength range. For the planar multilayer optics, different layered schemes are explored. Stacks of periodic multilayers and capping layers are demonstrated to achieve multi-channel reflection or suppression of the reflective properties. Aperiodic multilayer structures enable broadband reflection both in angles and wavelengths, with the possibility of polarization control. The broad wavelength band multilayer is also used to shape attosecond pulses for the study of ultrafast phenomena. Narrowband multilayer monochromators are delivered to bridge the resolution gap between crystals and regular multilayers. High spectral purity multilayers with innovated anti-reflection structures are shown to select spectrally clean XUV radiation from broadband X-ray sources, especially the plasma sources for EUV lithography. Significant progress is also made in the three dimensional multilayer optics, i.e., combining micro- and nanostructures with multilayers, in order to provide new freedom to tune the spectral response. Several kinds of multilayer gratings, including multilayer coated gratings, sliced multilayer gratings, and lamellar multilayer gratings are being pursued for high resolution and high efficiency XUV spectrometers/monochromators, with their advantages and disadvantages, respectively. Multilayer diffraction optics are also developed for spectral purity enhancement. New structures like gratings, zone plates, and pyramids that obtain full suppression of the unwanted radiation and high XUV reflectance are reviewed. Based on the present achievement of the spectral tailoring multilayer optics, the remaining challenges and opportunities for future researches are discussed.

Nanoscale friction properties of graphene and graphene oxide

DOE PAGES

Berman, Diana; Erdemir, Ali; Zinovev, Alexander V.; ...

2015-04-03

Achieving superlow friction and wear at the micro/nano-scales through the uses of solid and liquid lubricants may allow superior performance and long-lasting operations in a range of micromechanical system including micro-electro mechanical systems (MEMS). Previous studies have indicated that conventional solid lubricants such as highly ordered pyrolitic graphite (HOPG) can only afford low friction in humid environments at micro/macro scales; but, HOPG is not suitable for practical micro-scale applications. Here, we explored the nano-scale frictional properties of multi-layered graphene films as a potential solid lubricant for such applications. Atomic force microscopy (AFM) measurements have revealed that for high-purity multilayered graphenemore » (7–9 layers), the friction force is significantly lower than what can be achieved by the use of HOPG, regardless of the counterpart AFM tip material. We have demonstrated that the quality and purity of multilayered graphene plays an important role in reducing lateral forces, while oxidation of graphene results in dramatically increased friction values. Furthermore, for the first time, we demonstrated the possibility of achieving ultralow friction for CVD grown single layer graphene on silicon dioxide. This confirms that the deposition process insures a stronger adhesion to substrate and hence enables superior tribological performance than the previously reported mechanical exfoliation processes.« less

Stray field signatures of Néel textured skyrmions in Ir/Fe/Co/Pt multilayer films

NASA Astrophysics Data System (ADS)

Yagil, A.; Almoalem, A.; Soumyanarayanan, Anjan; Tan, Anthony K. C.; Raju, M.; Panagopoulos, C.; Auslaender, O. M.

2018-05-01

Skyrmions are nanoscale spin configurations with topological properties that hold great promise for spintronic devices. Here, we establish their Néel texture, helicity, and size in Ir/Fe/Co/Pt multilayer films by constructing a multipole expansion to model their stray field signatures and applying it to magnetic force microscopy images. Furthermore, the demonstrated sensitivity to inhomogeneity in skyrmion properties, coupled with a unique capability to estimate the pinning force governing dynamics, portend broad applicability in the burgeoning field of topological spin textures.

Are primary and secondary provoked vestibulodynia two different entities? A comparison of pain, psychosocial, and sexual characteristics.

PubMed

Aerts, Leen; Bergeron, Sophie; Corsini-Munt, Serena; Steben, Marc; Pâquet, Myriam

2015-06-01

Provoked vestibulodynia (PVD) is suspected to be the most frequent cause of vulvodynia in premenopausal women. Based on the onset of PVD relative to the start of sexual experience, PVD can be divided into primary (PVD1) and secondary PVD (PVD2). Studies comparing these PVD subgroups are inconclusive as to whether differences exist in sexual and psychosocial functioning. The aim of this study was to compare the pain, sexual and psychosocial functioning of a large clinical and community-based sample of premenopausal women with PVD1 and PVD2. A total of 269 women (n = 94 PVD1; n = 175 PVD2) completed measures on sociodemographics, pain, sexual, and psychosocial functioning. Dependent variables were the 0-10 pain numerical rating scale, McGill-Melzack Pain Questionnaire, Female Sexual Function Index, Global Measure of Sexual Satisfaction, Beck Depression Inventory-II, Painful Intercourse Self-Efficacy Scale, Pain Catastrophizing Scale, State-Trait Anxiety Inventory Trait Subscale, Ambivalence over Emotional Expression Questionnaire, Hurlbert Index of Sexual Assertiveness, Experiences in Close Relationships Scale--Revised, and Dyadic Adjustment Scale-Revised. At first sexual relationship, women with PVD2 were significantly younger than women with PVD1 (P < 0.01). The average relationship duration was significantly longer in women with PVD2 compared with women with PVD1 (P < 0.01). Although women with PVD1 described a significantly longer duration of pain compared with women with PVD2 (P < 0.01), no significant subtype differences were found in pain intensity during intercourse. When controlling for the sociodemographics mentioned earlier, no significant differences were found in sexual, psychological, and relational functioning between the PVD subgroups. Nevertheless, on average, both groups were in the clinical range of sexual dysfunction and reported impaired psychological functioning. The findings show that there are no significant differences in the sexual and psychosocial profiles of women with PVD1 and PVD2. Results suggest that similar psychosocial and sex therapy interventions should be offered to both subgroups of PVD. © 2015 International Society for Sexual Medicine.

A comparison of LIDT behavior of metal-dielectric mirrors in ns and ps pulse regime at 1030 nm with regard to the coating technology

NASA Astrophysics Data System (ADS)

Škoda, Václav; Vanda, Jan; Uxa, Štěpán

2017-11-01

Several sets of mirror samples with multilayer system Ta2O5/SiO2 on silver metal layer were manufactured using either PVD or IAD coating technology. Both BK7 and fused silica substrates were used for preparation of samples. Laserinduced- damage-threshold (LIDT) of metal-dielectric mirrors was tested using a laser apparatus working at 1030 nm wavelength, in ns and ps pulse length domains in S-on-1 test mode. The measured damage threshold values at 45 deg angle of incidence and P-polarization were compared for different pulse length, substrate materials and coating technology.

Review: mechanical behavior of metal/ceramic interfaces in nanolayered composites—experiments and modeling

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

Li, Nan; Liu, Xiang-Yang

In this study, recent experimental and modeling studies in nanolayered metal/ceramic composites are reviewed, with focus on the mechanical behaviors of metal/nitrides interfaces. The experimental and modeling studies of the slip systems in bulk TiN are reviewed first. Then, the experimental studies of interfaces, including co-deformation mechanism by micropillar compression tests, in situ TEM straining tests for the dynamic process of the co-deformation, thickness-dependent fracture behavior, and interrelationship among the interfacial bonding, microstructure, and mechanical response, are reviewed for the specific material systems of Al/TiN and Cu/TiN multilayers at nanoscale. The modeling studies reviewed cover first-principles density functional theory-based modeling,more » atomistic molecular dynamics simulations, and mesoscale modeling of nanolayered composites using discrete dislocation dynamics. The phase transformation between zinc-blende and wurtzite AlN phases in Al/AlN multilayers at nanoscale is also reviewed. Finally, a summary and perspective of possible research directions and challenges are given.« less

Review: mechanical behavior of metal/ceramic interfaces in nanolayered composites—experiments and modeling

DOE PAGES

Li, Nan; Liu, Xiang-Yang

2017-11-03

In this study, recent experimental and modeling studies in nanolayered metal/ceramic composites are reviewed, with focus on the mechanical behaviors of metal/nitrides interfaces. The experimental and modeling studies of the slip systems in bulk TiN are reviewed first. Then, the experimental studies of interfaces, including co-deformation mechanism by micropillar compression tests, in situ TEM straining tests for the dynamic process of the co-deformation, thickness-dependent fracture behavior, and interrelationship among the interfacial bonding, microstructure, and mechanical response, are reviewed for the specific material systems of Al/TiN and Cu/TiN multilayers at nanoscale. The modeling studies reviewed cover first-principles density functional theory-based modeling,more » atomistic molecular dynamics simulations, and mesoscale modeling of nanolayered composites using discrete dislocation dynamics. The phase transformation between zinc-blende and wurtzite AlN phases in Al/AlN multilayers at nanoscale is also reviewed. Finally, a summary and perspective of possible research directions and challenges are given.« less

Sub-wavelength modulation of χ (2) optical nonlinearity in organic thin films

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

Yan, Yixin; Yuan, Yakun; Wang, Baomin

Modulating the second-order nonlinear optical susceptibility (χ (2)) of materials at the nanoscale represents an ongoing technological challenge for a variety of integrated frequency conversion and nonlinear nanophotonic applications. Here we exploit the large hyperpolarizability of intermolecular charge transfer states, naturally aligned at an organic semiconductor donor–acceptor (DA) interface, as a means to control the magnitude and sign of χ (2) at the nanoscale. Focusing initially on a single pentacene-C 60 DA interface, we confirm that the charge transfer transition is strongly aligned orthogonal to the heterojunction and find that it is responsible for a large interfacial nonlinearity probed viamore » second harmonic generation that is sufficient to achieve d 33 > 10pm V –1, when incorporated in a non-centrosymmetric DA multilayer stack. Lastly, using grating-shadowed oblique-angle deposition to laterally structure the DA interface distribution in such multilayers subsequently enables the demonstration of a χ (2) grating with 280 nm periodicity, which is the shortest reported to date.« less

Sub-wavelength modulation of χ(2) optical nonlinearity in organic thin films

NASA Astrophysics Data System (ADS)

Yan, Yixin; Yuan, Yakun; Wang, Baomin; Gopalan, Venkatraman; Giebink, Noel C.

2017-01-01

Modulating the second-order nonlinear optical susceptibility (χ(2)) of materials at the nanoscale represents an ongoing technological challenge for a variety of integrated frequency conversion and nonlinear nanophotonic applications. Here we exploit the large hyperpolarizability of intermolecular charge transfer states, naturally aligned at an organic semiconductor donor-acceptor (DA) interface, as a means to control the magnitude and sign of χ(2) at the nanoscale. Focusing initially on a single pentacene-C60 DA interface, we confirm that the charge transfer transition is strongly aligned orthogonal to the heterojunction and find that it is responsible for a large interfacial nonlinearity probed via second harmonic generation that is sufficient to achieve d33>10 pm V-1, when incorporated in a non-centrosymmetric DA multilayer stack. Using grating-shadowed oblique-angle deposition to laterally structure the DA interface distribution in such multilayers subsequently enables the demonstration of a χ(2) grating with 280 nm periodicity, which is the shortest reported to date.

Quantitative x-ray phase imaging at the nanoscale by multilayer Laue lenses

PubMed Central

Yan, Hanfei; Chu, Yong S.; Maser, Jörg; Nazaretski, Evgeny; Kim, Jungdae; Kang, Hyon Chol; Lombardo, Jeffrey J.; Chiu, Wilson K. S.

2013-01-01

For scanning x-ray microscopy, many attempts have been made to image the phase contrast based on a concept of the beam being deflected by a specimen, the so-called differential phase contrast imaging (DPC). Despite the successful demonstration in a number of representative cases at moderate spatial resolutions, these methods suffer from various limitations that preclude applications of DPC for ultra-high spatial resolution imaging, where the emerging wave field from the focusing optic tends to be significantly more complicated. In this work, we propose a highly robust and generic approach based on a Fourier-shift fitting process and demonstrate quantitative phase imaging of a solid oxide fuel cell (SOFC) anode by multilayer Laue lenses (MLLs). The high sensitivity of the phase to structural and compositional variations makes our technique extremely powerful in correlating the electrode performance with its buried nanoscale interfacial structures that may be invisible to the absorption and fluorescence contrasts. PMID:23419650

Sub-wavelength modulation of χ (2) optical nonlinearity in organic thin films

DOE PAGES

Yan, Yixin; Yuan, Yakun; Wang, Baomin; ...

2017-01-27

Modulating the second-order nonlinear optical susceptibility (χ (2)) of materials at the nanoscale represents an ongoing technological challenge for a variety of integrated frequency conversion and nonlinear nanophotonic applications. Here we exploit the large hyperpolarizability of intermolecular charge transfer states, naturally aligned at an organic semiconductor donor–acceptor (DA) interface, as a means to control the magnitude and sign of χ (2) at the nanoscale. Focusing initially on a single pentacene-C 60 DA interface, we confirm that the charge transfer transition is strongly aligned orthogonal to the heterojunction and find that it is responsible for a large interfacial nonlinearity probed viamore » second harmonic generation that is sufficient to achieve d 33 > 10pm V –1, when incorporated in a non-centrosymmetric DA multilayer stack. Lastly, using grating-shadowed oblique-angle deposition to laterally structure the DA interface distribution in such multilayers subsequently enables the demonstration of a χ (2) grating with 280 nm periodicity, which is the shortest reported to date.« less

Body image in women with primary and secondary provoked vestibulodynia: a controlled study.

PubMed

Maillé, Delphine L; Bergeron, Sophie; Lambert, Bernard

2015-02-01

Provoked vestibulodynia (PVD) is a women's genito-pelvic pain condition associated with psychosexual impairments, including depression. Body image (BI) has been found to be different in women with primary (PVD1) and secondary (PVD2) PVD. No controlled study has compared BI in women with PVD1 and PVD2 and investigated its associations with sexual satisfaction, sexual function, and pain. The aims of this study were to (i) compare BI in women with PVD1, PVD2, and asymptomatic controls and (ii) to examine associations between BI and sexual satisfaction, sexual function, and pain during intercourse in women with PVD. Fifty-seven women (20 with PVD1, 19 with PVD2, and 18 controls) completed measures of BI, sexual satisfaction, sexual function, pain during intercourse, and depression. The main outcome measures were (i) Global Measure of Sexual Satisfaction Scale, (ii) Female Sexual Function Index, and (iii) pain numerical rating scale. Controlling for depression, women with PVD1 reported more body exposure anxiety during sexual activities than women with PVD2 and controls F(2,51)=4.23, P=0.02. For women with PVD, more negative BI during sexual activities was associated with lower sexual satisfaction (β=-0.45, P=0.02) and function (β=-0.39, P=0.04) and higher pain during intercourse (β=0.59, P=0.004). More positive body esteem was associated with higher sexual function (β=0.34, P=0.05). Findings suggest that women with PVD1 present more body exposure anxiety during sexual activities than women with PVD2 and asymptomatic women. Body esteem and general attitudes toward women's genitalia were not significantly different between groups. Higher body exposure anxiety during sexual activities was associated with poorer sexual outcomes in women with PVD. Further studies assessing interventions targeting BI during sexual activities in this population are needed, as improving BI during sexual interactions may enhance sexual outcomes in women with PVD. © 2014 International Society for Sexual Medicine.

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

Zhang, Rubing, E-mail: zrb86411680@126.com; Zhang, Yaoyao; Liu, Qiang

TiAl/Nb and TiAl/NiCoCrAl laminate composite sheets with a thickness of 0.4–0.6 mm and dimensions of 150 mm × 100 mm were successfully fabricated by electron beam physical vapor deposition. The microstructures of the sheets were examined, and their mechanical properties were compared with those of TiAl monolithic sheet produced by electron beam physical vapor deposition. Tensile testing was performed at room temperature and 750 °C, and the fracture surfaces were examined by scanning electron microscopy. Among the three microlaminate sheets, the TiAl/NiCoCrAl micro-laminate sheet had the best comprehensive properties at room temperature, and the TiAl/Nb micro-laminate sheet showed the idealmore » high-temperature strength and plasticity at 750 °C. The result was discussed in terms of metal strengthening mechanism. - Highlights: • TiAl-based multilayer foils was fabricated successfully by using EB-PVD method; • The tensile properties and micro-fracture morphologies of the sheet were investigated; • The deformation behavior of the multilayer foils was discussed.« less

Multilayer (TiN, TiAlN) ceramic coatings for nuclear fuel cladding

NASA Astrophysics Data System (ADS)

Alat, Ece; Motta, Arthur T.; Comstock, Robert J.; Partezana, Jonna M.; Wolfe, Douglas E.

2016-09-01

In an attempt to develop an accident-tolerant fuel (ATF) that can delay the deleterious consequences of loss-of-coolant-accidents (LOCA), multilayer coatings were deposited onto ZIRLO® coupon substrates by cathodic arc physical vapor deposition (CA-PVD). Coatings were composed of alternating TiN (top) and Ti1-xAlxN (2-layer, 4-layer, 8-layer and 16-layer) layers. The minimum TiN top coating thickness and coating architecture were optimized for good corrosion and oxidation resistance. Corrosion tests were performed in static pure water at 360 °C and 18.7 MPa for up to 90 days. The optimized coatings showed no spallation/delamination and had a maximum of 6 mg/dm2 weight gain, which is 6 times smaller than that of a control sample of uncoated ZIRLO® which showed a weight gain of 40.2 mg/dm2. The optimized architecture features a ∼1 μm TiN top layer to prevent boehmite phase formation during corrosion and a TiN/TiAlN 8-layer architecture which provides the best corrosion performance.

Defect Clustering and Nano-phase Structure Characterization of Multicomponent Rare Earth-Oxide-Doped Zirconia-Yttria Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Chen, Yuan L.; Miller, Robert A.

2004-01-01

Advanced thermal barrier coatings (TBCs) have been developed by incorporating multicomponent rare earth oxide dopants into zirconia-based thermal barrier coatings to promote the creation of the thermodynamically stable, immobile oxide defect clusters and/or nanophases within the coating systems. In this paper, the defect clusters, induced by Nd, Gd, and Yb rare earth dopants in the zirconia-yttria thermal barrier coatings, were characterized by high-resolution transmission electron microscopy (TEM). The TEM lattice imaging, selected area diffraction (SAD), and electron energy-loss spectroscopy (EELS) analyses demonstrated that the extensive nanoscale rare earth dopant segregation exists in the plasma-sprayed and electron-physical-vapor-deposited (EB PVD) thermal barrier coatings. The nanoscale concentration heterogeneity and the resulting large lattice distortion promoted the formation of parallel and rotational defective lattice clusters in the coating systems. The presence of the 5-to 100-nm-sized defect clusters and nanophases is believed to be responsible for the significant reduction of thermal conductivity, improved sintering resistance, and long-term high temperature stability of the advanced thermal barrier coating systems.

PvdN Enzyme Catalyzes a Periplasmic Pyoverdine Modification*

PubMed Central

Ringel, Michael T.; Dräger, Gerald; Brüser, Thomas

2016-01-01

Pyoverdines are high affinity siderophores produced by a broad range of pseudomonads to enhance growth under iron deficiency. They are especially relevant for pathogenic and mutualistic strains that inhabit iron-limited environments. Pyoverdines are generated from non-ribosomally synthesized highly modified peptides. They all contain an aromatic chromophore that is formed in the periplasm by intramolecular cyclization steps. Although the cytoplasmic peptide synthesis and side-chain modifications are well characterized, the periplasmic maturation steps are far from understood. Out of five periplasmic enzymes, PvdM, PvdN, PvdO, PvdP, and PvdQ, functions have been attributed only to PvdP and PvdQ. The other three enzymes are also regarded as essential for siderophore biosynthesis. The structure of PvdN has been solved recently, but no function could be assigned. Here we present the first in-frame deletion of the PvdN-encoding gene. Unexpectedly, PvdN turned out to be required for a specific modification of pyoverdine, whereas the overall amount of fluorescent pyoverdines was not altered by the mutation. The mutant strain grew normally under iron-limiting conditions. Mass spectrometry identified the PvdN-dependent modification as a transformation of the N-terminal glutamic acid to a succinamide. We postulate a pathway for this transformation catalyzed by the enzyme PvdN, which is most likely functional in the case of all pyoverdines. PMID:27703013

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

Mayle, Scott; Gupta, Tanuj; Davis, Sam

Monitoring of the intrinsic temperature and the thermal management is discussed for the carbon nanotube nano-circuits. The experimental results concerning fabricating and testing of a thermometer able to monitor the intrinsic temperature on nanoscale are reported. We also suggest a model which describes a bi-metal multilayer system able to filter the heat flow, based on separating the electron and phonon components one from another. The bi-metal multilayer structure minimizes the phonon component of the heat flow, while retaining the electronic part. The method allows one to improve the overall performance of the electronic nano-circuits due to minimizing the energy dissipation.

Patterning of magnetic thin films and multilayers using nanostructured tantalum gettering templates.

PubMed

Qiu, Wenlan; Chang, Long; Lee, Dahye; Dannangoda, Chamath; Martirosyan, Karen; Litvinov, Dmitri

2015-03-25

This work demonstrates that a nonmagnetic thin film of cobalt oxide (CoO) sandwiched between Ta seed and capping layers can be effectively reduced to a magnetic cobalt thin film by annealing at 200 °C, whereas CoO does not exhibit ferromagnetic properties at room temperature and is stable at up to ∼400 °C. The CoO reduction is attributed to the thermodynamically driven gettering of oxygen by tantalum, similar to the exothermic reduction-oxidation reaction observed in thermite systems. Similarly, annealing at 200 °C of a nonmagnetic [CoO/Pd]N multilayer thin film sandwiched between Ta seed and Ta capping layers results in the conversion into a magnetic [Co/Pd]N multilayer, a material with perpendicular magnetic anisotropy that is of interest for magnetic data storage applications. A nanopatterning approach is introduced where [CoO/Pd]N multilayers is locally reduced into [Co/Pd]N multilayers to achieve perpendicular magnetic anisotropy nanostructured array. This technique can potentially be adapted to nanoscale patterning of other systems for which thermodynamically favorable combination of oxide and gettering layers can be identified.

Layer specific optical band gap measurement at nanoscale in MoS{sub 2} and ReS{sub 2} van der Waals compounds by high resolution electron energy loss spectroscopy

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

Dileep, K., E-mail: dileep@jncasr.ac.in, E-mail: ranjan@jncasr.ac.in; Sahu, R.; Datta, R., E-mail: dileep@jncasr.ac.in, E-mail: ranjan@jncasr.ac.in

2016-03-21

Layer specific direct measurement of optical band gaps of two important van der Waals compounds, MoS{sub 2} and ReS{sub 2}, is performed at nanoscale by high resolution electron energy loss spectroscopy. For monolayer MoS{sub 2}, the twin excitons (1.8 and 1.95 eV) originating at the K point of the Brillouin zone are observed. An indirect band gap of 1.27 eV is obtained from the multilayer regions. Indirect to direct band gap crossover is observed which is consistent with the previously reported strong photoluminescence from the monolayer MoS{sub 2}. For ReS{sub 2}, the band gap is direct, and a value of 1.52 andmore » 1.42 eV is obtained for the monolayer and multilayer, respectively. The energy loss function is dominated by features due to high density of states at both the valence and conduction band edges, and the difference in analyzing band gap with respect to ZnO is highlighted. Crystalline 1T ReS{sub 2} forms two dimensional chains like superstructure due to the clustering between four Re atoms. The results demonstrate the power of HREELS technique as a nanoscale optical absorption spectroscopy tool.« less

Inter-diffusion analysis of joint interface of tungsten-rhenium couple

NASA Astrophysics Data System (ADS)

Hua, Y. F.; Li, Z. X.; Zhang, X.; Du, J. H.; Huang, C. L.; Du, M. H.

2011-09-01

The tungsten-rhenium couple was prepared by using glow plasma physical vapor deposition (PVD) on the isotropic fine grained graphite (IG) substrates. Diffusion anneals of the tungsten-rhenium couple were conducted at the temperature from 1100 °C to 1400 °C to investigate the inter-diffusion behaviors. The results showed that the thickness of the inter-diffusion zone increased with increasing annealing temperature. The relationship between the inter-diffusion coefficient and the annealing temperature accorded with the Arrhenius manner. The value of inter-diffusion activation energies was 189 kJ/mole (1.96 eV). The service time of tungsten-rhenium multilayer diffusion barrier was limited by the inter-diffusion for rhenium and tungsten rather than the diffusion of carbon in rhenium.

Investigation of sacrificial layer and building block for layered nanofabrication (LNF)

NASA Astrophysics Data System (ADS)

Shih, Ting-Yu

Layered Nanoscale Fabrication (LNF) is a "bottom-up" procedure that uses multiple layers to build 3-dimensional nanoscale structures. Here, in this dissertation, several candidates for sacrificial layers were explored, The thermal stability of gold nanoparticles and simple patterns are also reported. In order to obtain information on layer thickness and film quality; the samples were characterized using atomic force microscopy (AFM) and ellipsometry. Octadecyltrichlorosilane (OTS) was first investigated for use as a sacrificial layer and we studied filth growth by targeted self-replication of silane multilayers with and without the presence of thiolated gold nanoparticles on silicon oxide substrates. The particles adhered to the substrate during layer grafting. The film grew selectively on the substrate, without covering the particles. AFM was used to investigate the growth mechanism and the process of embedding the nanoparticles. OTS multilayer films up to 9 layers were grown in a linear, bilayer-by bilayer mode, free of islands and defects. We also report on studies of monolayer and multilayer formation of Methyl-11-dimethylmonochlorosilyl-undecanoate films. Flat multilayers up to 3-layers thick were grown. AFM was used to measure the height of an observable "edge" of the multilayer film and this provides and independent determination of the MOSUD layer height of 1.5 nm: However, the particles detached from the surface when we attempted to grow multilayer. One strategy of linking the particles to form 2D arrays, thermal activation in ambient air, was investigated. The morphological properties of flaked nanoparticles and structures on silicon oxide substrates before and after heating were characterized by using AFM. For widely separated 5 nm gold nanoparticles height decreased over 50% at 600 °C. Further heating to 630 °C caused most particles to completely disappear, with small amount of particle residue left on the surface. Particles positioned near to other particles first formed a neck-like structure at 570 °C and then deformed into one wide particle with tail-shape residue at 650 °C. Clusters of Au nanoparticles rearranged and became one large collide with particles residues left on the surface at 630 °C.

Simultaneous topographic and elemental chemical and magnetic contrast in scanning tunneling microscopy

DOEpatents

Rose, Volker; Preissner, Curt A; Hla, Saw-Wai; Wang, Kangkang; Rosenmann, Daniel

2014-09-30

A method and system for performing simultaneous topographic and elemental chemical and magnetic contrast analysis in a scanning, tunneling microscope. The method and system also includes nanofabricated coaxial multilayer tips with a nanoscale conducting apex and a programmable in-situ nanomanipulator to fabricate these tips and also to rotate tips controllably.

Cognitive, psychophysical, and neural correlates of vulvar pain in primary and secondary provoked vestibulodynia: a pilot study.

PubMed

Sutton, Katherine; Pukall, Caroline; Wild, Conor; Johnsrude, Ingrid; Chamberlain, Susan

2015-05-01

Provoked vestibulodynia (PVD) is a common condition characterized by localized, provoked pain that can be present since first vaginal penetration attempt (primary) or can develop after a period of pain-free penetration (secondary). Research has demonstrated psychosocial and psychophysical differences between women with these subtypes of PVD, but the question of whether neural responses to pain also differ remains to be investigated. This study aims to examine whether cognitive, psychophysical, and neural responses to vulvar pressure pain differ between women with PVD1 and PVD2. Women with PVD1 and PVD2 were compared for group differences using multiple modalities, including questionnaires, psychophysical testing, and neuroimaging. Pain ratings were held constant across groups, rather than amount of pressure applied. Demographics, sexual functioning, four questionnaires examining anxiety and catastrophizing, quantitative sensory testing at the vulvar vestibule using a vulvalgesiometer, and functional and structural magnetic resonance imaging (MRI). Findings suggest that women with PVD1 are more anxious and that they catastrophize more about their vulvar and nonvulvar pain than women with PVD2. Overall, MRI results demonstrated structural and functional similarities to other chronic pain findings for both groups of women. Gray matter (GM) density also differed between groups: women with PVD1 showed significant decreases in GM throughout areas associated with pain processing. Functionally, between-groups differences were found during painful vulvar stimulation despite lower pressures applied to the vulva for women with PVD1 because of their heightened sensitivity; the determination of the level of vulvar pressure to elicit pain was based on subjective ratings. Findings are limited by sample size and liberal alpha values; however, future research is certainly warranted based on the preliminary findings of this study suggesting both similarities and differences between PVD1 and PVD2. Overall, women with PVD1 seem to fare worse on several pain-related and psychosocial variables compared with women with PVD2. © 2015 International Society for Sexual Medicine.

A comparison of demographic and psychosexual characteristics of women with primary versus secondary provoked vestibulodynia.

PubMed

Brotto, Lori A; Sadownik, Leslie A; Thomson, Sydney; Dayan, Marcy; Smith, Kelly B; Seal, Brooke N; Moses, Melissa; Zhang, Areiyu

2014-05-01

Provoked vestibulodynia (PVD) is a distressing genital pain condition affecting approximately 12% of premenopausal women. It has been speculated that primary (ie, lifelong) and secondary (ie, acquired) PVD may represent 2 distinct conditions with different etiologies. There is also evidence that primary and secondary PVD subtypes may respond differently to conventional treatments. The goal of this study was to compare the demographic, clinical, and psychosexual characteristics of a large sample of premenopausal women with primary and secondary PVD. A total of 132 premenopausal women (n=42 primary; n=90 secondary) with PVD who sought treatment in a Multidisciplinary Vulvodynia Program completed demographic questions and a battery of validated self-report measures before treatment. Women with primary PVD had a longer duration of PVD as well as more time before diagnosis. Women with secondary PVD reported significantly more clitoral hood pain, higher overall vestibular pain levels, more overall sexual dysfunction and sex-related distress, and proportionately more intercourse occasions that were painful. Women with primary pain stated they had significantly more dysmenorrhea and were more likely to report that their partners were unaware of their PVD symptoms. There were no significant subtype differences on any psychological measure but a trend towards higher magnification of symptoms in women with secondary PVD. Overall the findings suggest some important differences in the characteristics of women with primary versus secondary PVD which may have management-related implications.

Thermometry and thermal management of carbon nanotube circuits

NASA Astrophysics Data System (ADS)

Mayle, Scott; Gupta, Tanuj; Davis, Sam; Chandrasekhar, Venkat; Shafraniuk, Serhii

2015-05-01

Monitoring of the intrinsic temperature and the thermal management is discussed for the carbon nanotube nano-circuits. The experimental results concerning fabricating and testing of a thermometer able to monitor the intrinsic temperature on nanoscale are reported. We also suggest a model which describes a bi-metal multilayer system able to filter the heat flow, based on separating the electron and phonon components one from another. The bi-metal multilayer structure minimizes the phonon component of the heat flow, while retaining the electronic part. The method allows one to improve the overall performance of the electronic nano-circuits due to minimizing the energy dissipation.

Identification of Inhibitors of PvdQ, an Enzyme Involved in the Synthesis of the Siderophore Pyoverdine

PubMed Central

2015-01-01

Pseudomonas aeruginosa produces the peptide siderophore pyoverdine, which is used to acquire essential Fe3+ ions from the environment. PvdQ, an Ntn hydrolase, is required for the biosynthesis of pyoverdine. PvdQ knockout strains are not infectious in model systems, suggesting that disruption of siderophore production via PvdQ inhibition could be exploited as a target for novel antibacterial agents, by preventing cells from acquiring iron in the low iron environments of most biological settings. We have previously described a high-throughput screen to identify inhibitors of PvdQ that identified inhibitors with IC50 values of ∼100 μM. Here, we describe the discovery of ML318, a biaryl nitrile inhibitor of PvdQ acylase. ML318 inhibits PvdQ in vitro (IC50 = 20 nM) by binding in the acyl-binding site, as confirmed by the X-ray crystal structure of PvdQ bound to ML318. Additionally, the PvdQ inhibitor is active in a whole cell assay, preventing pyoverdine production and limiting the growth of P. aeruginosa under iron-limiting conditions. PMID:24824984

Nanoscale strengthening mechanisms in metallic thin film systems

NASA Astrophysics Data System (ADS)

Schoeppner, Rachel Lynn

Nano-scale strengthening mechanisms for thin films were investigated for systems governed by two different strengthening techniques: nano-laminate strengthening and oxide dispersion strengthening. Films were tested under elevated temperature conditions to investigate changes in deformation mechanisms at different operating temperatures, and the structural stability. Both systems exhibit remarkable stability after annealing and thus long-term reliability. Nano-scale metallic multilayers with smaller layer thicknesses show a greater relative resistance to decreasing strength at higher temperature testing conditions than those with larger layer thicknesses. This is seen in both Cu/Ni/Nb multilayers as well as a similar tri-component bi-layer system (Cu-Ni/Nb), which removed the coherent interface from the film. Both nanoindentation and micro-pillar compression tests investigated the strain-hardening ability of these two systems to determine what role the coherent interface plays in this mechanism. Tri-layer films showed a higher strain-hardening ability as the layer thickness decreased and a higher strain-hardening exponent than the bi-layer system: verifying the presence of a coherent interface increases the strain-hardening ability of these multilayer systems. Both systems exhibited hardening of the room temperature strength after annealing, suggesting a change in microstructure has occurred, unlike that seen in other multilayer systems. Oxide dispersion strengthened Au films showed a marked increase in hardness and wear resistance with the addition of ZnO particles. The threshold for stress-induced grain-refinement as opposed to grain growth is seen at concentrations of at least 0.5 vol%. These systems exhibited stable microstructures during thermal cycling in films containing at least 1.0%ZnO. Nanoindentation experiments show the drop in hardness following annealing is almost completely attributed to the resulting grain growth. Four-point probe resistivity measurements on annealed films showed a significant drop in resistivity for the higher concentration ZnO films, which is proposed to be the result of a change in the particle-matrix interface structure. A model connecting the hardness and resistivity as a function of ZnO concentration has been developed based on the assumption that the impact of nm-scale ZnO precipitates on the mechanical and electrical behavior of Au films is likely dominated by a transition from semi-coherent to incoherent interfaces.

Tuning compliance of nanoscale polyelectrolyte multilayers to modulate cell adhesion.

PubMed

Thompson, Michael T; Berg, Michael C; Tobias, Irene S; Rubner, Michael F; Van Vliet, Krystyn J

2005-12-01

It is well known that mechanical stimuli induce cellular responses ranging from morphological reorganization to mineral secretion, and that mechanical stimulation through modulation of the mechanical properties of cell substrata affects cell function in vitro and in vivo. However, there are few approaches by which the mechanical compliance of the substrata to which cells adhere and grow can be determined quantitatively and varied independent of substrata chemical composition. General methods by which mechanical state can be quantified and modulated at the cell population level are critical to understanding and engineering materials that promote and maintain cell phenotype for applications such as vascular tissue constructs. Here, we apply contact mechanics of nanoindentation to measure the mechanical compliance of weak polyelectrolyte multilayers (PEMs) of nanoscale thickness, and explore the effects of this tunable compliance for cell substrata applications. We show that the nominal elastic moduli E(s) of these substrata depend directly on the pH at which the PEMs are assembled, and can be varied over several orders of magnitude for given polycation/polyanion pairs. Further, we demonstrate that the attachment and proliferation of human microvascular endothelial cells (MVECs) can be regulated through independent changes in the compliance and terminal polyion layer of these PEM substrata. These data indicate that substrate mechanical compliance is a strong determinant of cell fate, and that PEMs of nanoscale thickness provide a valuable tool to vary the external mechanical environment of cells independently of chemical stimuli.

A hermetic and room-temperature wafer bonding technique based on integrated reactive multilayer systems

NASA Astrophysics Data System (ADS)

Braeuer, J.; Gessner, T.

2014-11-01

This paper focuses on direct deposition and patterning of reactive and nano-scale multilayer films at wafer level. These multilayer structures are called integrated reactive material systems (iRMS). In contrast to the typically used nickel (Ni)/ aluminum (Al) systems, in this work we needed to have our total multilayer film thicknesses smaller than 2.5 µm to reduce stress within the multilayer as well as deposition costs. Thus, we introduced new high energetic iRMS. These films were deposited by using alternating magnetron sputtering from high purity Al- and palladium (Pd)-targets to obtain films with a defined Al:Pd atomic ratio. In this paper, we present the result for reaction characteristics and reaction velocities which were up to 72.5 m s-1 for bond frames with lateral dimensions as low as 20 µm. Furthermore, the feasibility of silicon (Si)-Si, Si-glass as well as Si-ceramic hermetic and metallic wafer bonding at room temperature is presented. We show that by using this bond technology, strong (maximum shear strengths of 235 MPa) and hermetically sealed bond interfaces can be achieved without any additional solder material.

Optogenetic analysis of a nociceptor neuron and network reveals ion channels acting downstream of primary sensors.

PubMed

Husson, Steven J; Costa, Wagner Steuer; Wabnig, Sebastian; Stirman, Jeffrey N; Watson, Joseph D; Spencer, W Clay; Akerboom, Jasper; Looger, Loren L; Treinin, Millet; Miller, David M; Lu, Hang; Gottschalk, Alexander

2012-05-08

Nociception generally evokes rapid withdrawal behavior in order to protect the tissue from harmful insults. Most nociceptive neurons responding to mechanical insults display highly branched dendrites, an anatomy shared by Caenorhabditis elegans FLP and PVD neurons, which mediate harsh touch responses. Although several primary molecular nociceptive sensors have been characterized, less is known about modulation and amplification of noxious signals within nociceptor neurons. First, we analyzed the FLP/PVD network by optogenetics and studied integration of signals from these cells in downstream interneurons. Second, we investigated which genes modulate PVD function, based on prior single-neuron mRNA profiling of PVD. Selectively photoactivating PVD, FLP, and downstream interneurons via Channelrhodopsin-2 (ChR2) enabled the functional dissection of this nociceptive network, without interfering signals by other mechanoreceptors. Forward or reverse escape behaviors were determined by PVD and FLP, via integration by command interneurons. To identify mediators of PVD function, acting downstream of primary nocisensor molecules, we knocked down PVD-specific transcripts by RNAi and quantified light-evoked PVD-dependent behavior. Cell-specific disruption of synaptobrevin or voltage-gated Ca(2+) channels (VGCCs) showed that PVD signals chemically to command interneurons. Knocking down the DEG/ENaC channel ASIC-1 and the TRPM channel GTL-1 indicated that ASIC-1 may extend PVD's dynamic range and that GTL-1 may amplify its signals. These channels act cell autonomously in PVD, downstream of primary mechanosensory molecules. Our work implicates TRPM channels in modifying excitability of and DEG/ENaCs in potentiating signal output from a mechano-nociceptor neuron. ASIC-1 and GTL-1 homologs, if functionally conserved, may denote valid targets for novel analgesics. Copyright © 2012 Elsevier Ltd. All rights reserved.

Adhesive and tribocorrosive behavior of TiAlPtN/TiAlN/TiAl multilayers sputtered coatings over CoCrMo

NASA Astrophysics Data System (ADS)

Canto, C. E.; Andrade, E.; Rocha, M. F.; Alemón, B.; Flores, M.

2017-09-01

The tribocorrosion resistance and adherence of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by PVD reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt in order to enhance the tribocorrosion resistance of a biomedical alloy of CoCrMo. Tribocorrosion tests were performed using Simulated Body Fluid (SBF) at typical body temperature with a tribometer in a pin on disk test. The elemental composition and thickness of the coating which behave better at the tribocorrosion tests were evaluated by means of RBS (Rutherford Backscattering Spectroscopy) IBA (Ion Beam Analysis) technique, using an alpha particles beam of 1.8 MeV, before and after the reciprocating motion in the tribocorrosion test. In order to simulate the elemental profile of the samples, the SIMNRA simulation computer code was used. Measurements of the adhesion of the coatings to the substrate were carried on by means of a scratch test using a tribometer. By taking micrographs of the produced tracks, the critical loads at which the coatings are fully separated from the substrate were determined. From these tests it was observed that a coating with 10 min of TiAlPtN in a TiAlPtN/TiAl period of 30 min in multilayers of 10 periods and with an average thickness of 145 nm for the TiAlPtN nanolayers had the best tribocorrosion resistance behavior, compared to that of the CoCrMo alloy. The RBS experiments showed a reduction of the thickness of the films along with some loss of the multilayer structure after the reciprocating motion. The adhesion tests indicated that the multilayer with the average TiAlPtN thickness of 145 nm displayed the highest critical load. These results indicate a high correlation between the adherence and the tribocorrosion behavior.

Metallic multilayers at the nanoscale

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

Jankowski, A.F.

1994-11-01

The development of multilayer structures has been driven by a wide range of commercial applications requiring enhanced material behaviors. Innovations in physical vapor deposition technologies, in particular magnetron sputtering, have enabled the synthesis of metallic-based structures with nanoscaled layer dimensions as small as one-to-two monolayers. Parameters used in the deposition process are paramount to the Formation of these small layer dimensions and the stability of the structure. Therefore, optimization of the desired material properties must be related to assessment of the actual microstructure. Characterization techniques as x-ray diffraction and high resolution microscopy are useful to reveal the interface and layermore » structure-whether ordered or disordered crystalline, amorphous, compositionally abrupt or graded, and/or lattice strained Techniques for the synthesis of metallic multilayers with subnanometric layers will be reviewed with applications based on enhancing material behaviors as reflectivity and magnetic anisotropy but with emphasis on experimental studies of mechanical properties.« less

C. elegans multi-dendritic sensory neurons: morphology and function

PubMed Central

Albeg, Adi; Smith, Cody; Chatzigeorgiou, Marios; Feitelson, Dror G.; Hall, David H.; Schafer, William R.; Miller, David M.; Treinin, Millet

2010-01-01

PVD and FLP sensory neurons envelope the body of the C. elegans adult with a highly branched network of thin sensory processes. Both PVD and FLP neurons are mechanosensors. PVD is known to mediate the response to high threshold mechanical stimuli. Thus PVD and FLP neurons are similar in both morphology and function to mammalian nociceptors. To better understand the function of these neurons we generated strains lacking them. Behavioral analysis shows that PVD and FLP regulate movement under normal growth conditions, as animals lacking these neurons demonstrate higher dwelling behavior. In addition, PVD—whose thin branches project across the body-wall muscles—may have a role in proprioception, as ablation of PVD leads to defective posture. Moreover, movement-dependent calcium transients are seen in PVD, a response that requires MEC-10, a subunit of the mechanosensory DEG/ENaC channel that is also required for maintaining wild-type posture. Hence, PVD senses both noxious and innocuous signals to regulate C. elegans behavior, and thus combines the functions of multiple mammalian somatosensory neurons. Finally, strong mechanical stimulation leads to inhibition of egg-laying, and this response also depends on PVD and FLP neurons. Based on all these results we suggest that noxious signals perceived by PVD and FLP promote an escape behavior consisting of increased speed, reduced pauses and reversals, and inhibition of egg-laying. PMID:20971193

Self-Assembled Nanoporous Biofilms from Functionalized Nanofibrous M13 Bacteriophage.

PubMed

Devaraj, Vasanthan; Han, Jiye; Kim, Chuntae; Kang, Yong-Cheol; Oh, Jin-Woo

2018-06-12

Highly periodic and uniform nanostructures, based on a genetically engineered M13 bacteriophage, displayed unique properties at the nanoscale that have the potential for a variety of applications. In this work, we report a multilayer biofilm with self-assembled nanoporous surfaces involving a nanofiber-like genetically engineered 4E-type M13 bacteriophage, which was fabricated using a simple pulling method. The nanoporous surfaces were effectively formed by using the networking-like structural layers of the M13 bacteriophage during self-assembly. Therefore, an external template was not required. The actual M13 bacteriophage-based fabricated multilayered biofilm with porous nanostructures agreed well with experimental and simulation results. Pores formed in the final layer had a diameter of about 150⁻500 nm and a depth of about 15⁻30 nm. We outline a filter application for this multilayered biofilm that enables selected ions to be extracted from a sodium chloride solution. Here, we describe a simple, environmentally friendly, and inexpensive fabrication approach with large-scale production potential. The technique and the multi-layered biofilms produced may be applied to sensor, filter, plasmonics, and bio-mimetic fields.

Frequency dependence of electrical properties of polyvinylidene fluoride/graphite electrode waste/natural carbon black composite

NASA Astrophysics Data System (ADS)

Insiyanda, D. R.; Indayaningsih, N.; Prihandoko, B.; Subhan, A.; Khaerudini, D. S.; Widodo, H.; Destyorini, F.; Chaer, A.

2018-03-01

Polyvinylidene fluoride (PVdF) is a semi-crystalline thermoplastic material with remarkably high piezoelectric coefficient and an attractive polymer matrix for micro-composite with superior mechanical and electrical properties. The conductive filler is obtained from Graphite Electrode Waste (GEW) and Natural Carbon Black (NCB). The variation of composite content (%) of PVdF/NCB/GEW were 100/0/0, 95/5/0, 95/0/5, 95/2.5/2.5. This experiment employed dry dispersion method for material mixing. The materials were then moulded using hot press machine with compression parameters of P = 5.5 MPa, T = 150 °C, t = 60 minutes, A = 5×5×(0.2 - 0.4) cm3. The electrical conductivity properties of pure PVdF, as well as PVdF/GEW, PVdF/NCB, and PVdF/NCB/GEW composites were investigated in a frequency range of 100 to 100000 Hz. The PVdF/GEW sample obtained the highest electrical conductivity. It is concluded that GEW and NCB can be incorporated into PVdF as a conductive filler to increase the conductivity of conductive material composite without solvent.

Psychological Treatments for Provoked Vestibulodynia: Integration of Mindfulness-Based and Cognitive Behavioral Therapies.

PubMed

Dunkley, Cara R; Brotto, Lori A

2016-07-01

Provoked vestibulodynia (PVD) is a chronic and distressing genital pain condition involving sharp pain to the vulvar vestibule with lifetime prevalence as high as 12%. PVD is the most prevalent cause of pain during sexual intercourse (dyspareunia) in premenopausal women, and gives rise to considerable sexual and relational concerns. As intercourse for women with PVD is either painful or impossible, PVD has pronounced negative effects on women's romantic relationship adjustment and sexual intimacy, as well as their emotional well-being and sense of sexual self-efficacy. Given the low efficacy and high side-effect profile of medications for the treatment of PVD, attention has shifted toward psychological interventions over the past decade. Psychological treatments for PVD have the advantage of targeting both the experience of pain and its many psychosexual consequences, such as reduced desire and arousal. Cognitive behavioral therapy (CBT) currently represents one of the most popular first-line psychological interventions for PVD. Mindfulness has been increasingly used alongside, or instead of CBT for a variety of health-related conditions, particularly with respect to chronic pain disorders and more recently in women with PVD. This review provides a detailed overview of CBT and mindfulness-based approaches in treating PVD. © 2016 Wiley Periodicals, Inc.

In situ nanoindentation study of plastic Co-deformation in Al-TiN nanocomposites

DOE PAGES

Li, N.; Wang, H.; Misra, A.; ...

2014-10-16

We performed in situ indentation in a transmission electron microscope on Al-TiN multilayers with individual layer thicknesses of 50 nm, 5 nm and 2.7 nm to explore the effect of length scales on the plastic co-deformability of a metal and a ceramic. At 50 nm, plasticity was confined to the Al layers with easy initiation of cracks in the TiN layers. At 5 nm and below, cracking in TiN was suppressed and post mortem measurements indicated a reduction in layer thickness in both layers. Our results demonstrate the profound size effect in enhancing plastic co-deformability in nanoscale metal-ceramic multilayers.

Multilayered membranes with tuned well arrays to be used as regenerative patches.

PubMed

Martins, Nádia I; Sousa, Maria P; Custódio, Catarina A; Pinto, Vânia C; Sousa, Paulo J; Minas, Graça; Cleymand, Franck; Mano, João F

2017-07-15

Membranes have been explored as patches in tissue repair and regeneration, most of them presenting a flat geometry or a patterned texture at the nano/micrometer scale. Herein, a new concept of a flexible membrane featuring well arrays forming pore-like environments to accommodate cell culture is proposed. The processing of such membranes using polysaccharides is based on the production of multilayers using the layer-by-layer methodology over a patterned PDMS substrate. The detached multilayered membrane exhibits a layer of open pores at one side and a total thickness of 38±2.2µm. The photolithography technology used to produce the molds allows obtaining wells on the final membranes with a tuned shape and micro-scale precision. The influence of post-processing procedures over chitosan/alginate films with 100 double layers, including crosslinking with genipin or fibronectin immobilization, on the adhesion and proliferation of human osteoblast-like cells is also investigated. The results suggest that the presence of patterned wells affects positively cell adhesion, morphology and proliferation. In particular, it is seen that cells colonized preferentially the well regions. The geometrical features with micro to sub-millimeter patterned wells, together with the nano-scale organization of the polymeric components along the thickness of the film will allow to engineer highly versatile multilayered membranes exhibiting a pore-like microstructure in just one of the sides, that could be adaptable in the regeneration of multiple tissues. Flexible multilayered membranes containing multiple micro-reservoirs are found as potential regenerative patches. Layer-by-layer (LbL) methodology over a featured PDMS substrate is used to produce patterned membranes, composed only by natural-based polymers, that can be easily detached from the PDMS substrate. The combination of nano-scale control of the polymeric organization along the thickness of the chitosan/alginate (CHT/ALG) membranes, provided by LbL, together with the geometrical micro-scale features of the patterned membranes offers a uniqueness system that allows cells to colonize 3-dimensionally. This study provides a promising strategy to control cellular spatial organization that can face the region of the tissue to regenerate. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Design and function of biomimetic multilayer water purification membranes

PubMed Central

Ling, Shengjie; Qin, Zhao; Huang, Wenwen; Cao, Sufeng; Kaplan, David L.; Buehler, Markus J.

2017-01-01

Multilayer architectures in water purification membranes enable increased water throughput, high filter efficiency, and high molecular loading capacity. However, the preparation of membranes with well-organized multilayer structures, starting from the nanoscale to maximize filtration efficiency, remains a challenge. We report a complete strategy to fully realize a novel biomaterial-based multilayer nanoporous membrane via the integration of computational simulation and experimental fabrication. Our comparative computational simulations, based on coarse-grained models of protein nanofibrils and mineral plates, reveal that the multilayer structure can only form with weak interactions between nanofibrils and mineral plates. We demonstrate experimentally that silk nanofibril (SNF) and hydroxyapatite (HAP) can be used to fabricate highly ordered multilayer membranes with nanoporous features by combining protein self-assembly and in situ biomineralization. The production is optimized to be a simple and highly repeatable process that does not require sophisticated equipment and is suitable for scaled production of low-cost water purification membranes. These membranes not only show ultrafast water penetration but also exhibit broad utility and high efficiency of removal and even reuse (in some cases) of contaminants, including heavy metal ions, dyes, proteins, and other nanoparticles in water. Our biomimetic design and synthesis of these functional SNF/HAP materials have established a paradigm that could lead to the large-scale, low-cost production of multilayer materials with broad spectrum and efficiency for water purification, with applications in wastewater treatment, biomedicine, food industry, and the life sciences. PMID:28435877

Design and function of biomimetic multilayer water purification membranes.

PubMed

Ling, Shengjie; Qin, Zhao; Huang, Wenwen; Cao, Sufeng; Kaplan, David L; Buehler, Markus J

2017-04-01

Multilayer architectures in water purification membranes enable increased water throughput, high filter efficiency, and high molecular loading capacity. However, the preparation of membranes with well-organized multilayer structures, starting from the nanoscale to maximize filtration efficiency, remains a challenge. We report a complete strategy to fully realize a novel biomaterial-based multilayer nanoporous membrane via the integration of computational simulation and experimental fabrication. Our comparative computational simulations, based on coarse-grained models of protein nanofibrils and mineral plates, reveal that the multilayer structure can only form with weak interactions between nanofibrils and mineral plates. We demonstrate experimentally that silk nanofibril (SNF) and hydroxyapatite (HAP) can be used to fabricate highly ordered multilayer membranes with nanoporous features by combining protein self-assembly and in situ biomineralization. The production is optimized to be a simple and highly repeatable process that does not require sophisticated equipment and is suitable for scaled production of low-cost water purification membranes. These membranes not only show ultrafast water penetration but also exhibit broad utility and high efficiency of removal and even reuse (in some cases) of contaminants, including heavy metal ions, dyes, proteins, and other nanoparticles in water. Our biomimetic design and synthesis of these functional SNF/HAP materials have established a paradigm that could lead to the large-scale, low-cost production of multilayer materials with broad spectrum and efficiency for water purification, with applications in wastewater treatment, biomedicine, food industry, and the life sciences.

Electrophoretic build-up of alternately multilayered films and micropatterns based on graphene sheets and nanoparticles and their applications in flexible supercapacitors.

PubMed

Niu, Zhiqiang; Du, Jianjun; Cao, Xuebo; Sun, Yinghui; Zhou, Weiya; Hng, Huey Hoon; Ma, Jan; Chen, Xiaodong; Xie, Sishen

2012-10-22

Graphene nanosheets and metal nanoparticles (NPs) have been used as nano-building-blocks for assembly into macroscale hybrid structures with promising performance in electrical devices. However, in most graphene and metal NP hybrid structures, the graphene sheets and metal NPs (e.g., AuNPs) do not enable control of the reaction process, orientation of building blocks, and organization at the nanoscale. Here, an electrophoretic layer-by-layer assembly for constructing multilayered reduced graphene oxide (RGO)/AuNP films and lateral micropatterns is presented. This assembly method allows easy control of the nano-architecture of building blocks along the normal direction of the film, including the number and thickness of RGO and AuNP layers, in addition to control of the lateral orientation of the resultant multilayered structures. Conductivity of multilayered RGO/AuNP hybrid nano-architecture shows great improvement caused by a bridging effect of the AuNPs along the out-of-plane direction between the upper and lower RGO layers. The results clearly show the potential of electrophoretic build-up in the fabrication of graphene-based alternately multilayered films and patterns. Finally, flexible supercapacitors based on multilayered RGO/AuNP hybrid films are fabricated, and excellent performance, such as high energy and power densities, are achieved. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The decline of soil due to the pile of highway project Medan-Kualanamu (STA 35 + 901) with the finite element method

NASA Astrophysics Data System (ADS)

Hastuty, I. P.; Roesyanto; Sihite, A. B.

2018-02-01

Consolidation is the process of discharge of water from the ground through the pore cavity. Consolidation occurs in soft soil or unstable soil that allows an improvement in order to make the soil more stable. The method of using Prefabricated Vertical Drain (PVD) is one way to improve unstable soils. PVD works like a sand column that can drain water vertically. This study aims to determine the decrease, pore water pressure and soil consolidation rate with Prefabricated Vertical Drain (PVD) and without PVD analytically and using finite element method that affect the duration of soil decline to reach 90% consolidation or in other words soil does not decline anymore. Based on the analytical calculation, the decrease obtained is equal to 0.47 m meanwhile the result of calculation using finite element method is 0.45 m. The consolidation rate obtained from analytical calculation is 19 days with PVD and 115 days without PVD. The consolidation rate obtained from finite element method is 63 days with PVD and 110 days without PVD. And the pore water pressure is 0.92 KN/m2.

Raman microscopic studies of PVD deposited hard ceramic coatings

NASA Astrophysics Data System (ADS)

Constable, Christopher Paul

PVD hard ceramic coatings grown via the combined cathodic arc/unbalance magnetron deposition process were studied using Raman microscopy. Characteristic spectra from binary, multicomponent, multilayered and superlattice coatings were acquired to gain knowledge of the solid-state physics associated with Raman scattering from polycrystalline PVD coatings and to compile a comprehensive spectral database. Defect-induced first order scattering mechanisms were observed which gave rise to two pronounced groups of bands related to the acoustical (150-300cm[-1]) and optical (400-750cm[-1]) parts of the phonon spectrum. Evidence was gathered to support the theory that the optic modes were mainly due to the vibrations of the lighter elements and the acoustic modes due to the vibrations of the heavier elements within the lattice.A study into the deformation and disordering on the Raman spectral bands of PVD coatings was performed. TiAIN and TiZrN coatings were intentionally damaged via scratching methods. These scratches were then analysed by Raman mapping, both across and along, and a detailed spectral interpretation performed. Band broadening occurred which was related to "phonon relaxation mechanisms" as a direct result of the breaking up of coating grains resulting in a larger proportion of grain boundaries per-unit-volume. A direct correlation of the amount of damage with band width was observed. Band shifts were also found to occur which were due to the stresses caused by the scratching process. These shifts were found to be the largest at the edges of scratches. The Raman mapping of "droplets", a defect inherent to PVD deposition processes, found that higher compressive stresses and large amounts of disorder occurred for coating growth onto droplets.Strategies designed to evaluate the ability of Raman microscopy to monitor the extent of real wear on cutting tools were evaluated. The removal of a coating layer and subsequent detection of a base layer proved successful. This was then expanded to real wear situations in which tools were monitored after 3,6,12,64,120 and 130 minutes-in-cut. A PCA chemometrics model able to distinguish between component layers and oxides was developed.Raman microscopy was found to provide structural and compositional information on oxide scales formed on the surfaces of heat-treated coatings. Wear debris, generated as a consequence of sliding wear tests on various coatings, was also found to be primarily oxide products. The comparison of the oxide types within the debris to those formed on the surface of the same coating statically oxidised, facilitated a contact temperature during sliding to be estimated.Raman microscopy, owing to the piezo-spectroscopic effect, is sensitive to stress levels. The application of Raman microscopy for the determination of residual compressive stresses within PVD coatings was evaluated. TiAlN/VN superlattice coatings with engineered stresses ranging -3 to -11.3 GPa were deposited onto SS and HSS substrates. Subsequent Raman measurements found a correlation coefficient of 0.996 between Raman band position and stress (determined via XRD methods). In addition, there was also a similar correlation coefficient observed between hardness and Raman shift (cm-1). The application of mechanical stresses on a TiAlCrN coating via a stress rig was investigated and tensile and compressive shifts were observed.

The indispensable role of the transversal spin fluctuations mechanism in laser-induced demagnetization of Co/Pt multilayers with nanoscale magnetic domains.

PubMed

Zhang, Wei; He, Wei; Peng, Li-Cong; Zhang, Ying; Cai, Jian-Wang; Evans, Richard F L; Zhang, Xiang-Qun; Cheng, Zhao-Hua

2018-07-06

The switching of magnetic domains induced by an ultrashort laser pulse has been demonstrated in nanostructured ferromagnetic films. This leads to the dawn of a new era in breaking the ultimate physical limit for the speed of magnetic switching and manipulation, which is relevant to current and future information storage. However, our understanding of the interactions between light and spins in magnetic heterostructures with nanoscale domain structures is still lacking. Here, both time-resolved magneto-optical Kerr effect experiments and atomistic simulations are carried out to investigate the dominant mechanism of laser-induced ultrafast demagnetization in [Co/Pt] 20 multilayers with nanoscale magnetic domains. It is found that the ultrafast demagnetization time remains constant with various magnetic configurations, indicating that the domain structures play a minor role in laser-induced ultrafast demagnetization. In addition, both in experiment and atomistic simulations, we find a dependence of ultrafast demagnetization time τ M on the laser fluence, which is in contrast to the observations of spin transport within magnetic domains. The remarkable agreement between experiment and atomistic simulations indicates that the local dissipation of spin angular momentum is the dominant demagnetization mechanism in this system. More interestingly, we made a comparison between the atomistic spin dynamic simulation and the longitudinal spin flip model, highlighting that the transversal spin fluctuations mechanism is responsible for the ultrafast demagnetization in the case of inhomogeneous magnetic structures. This is a significant advance in clarifying the microscopic mechanism underlying the process of ultrafast demagnetization in inhomogeneous magnetic structures.

Direct optical imaging of nanoscale internal organization of polymer films

NASA Astrophysics Data System (ADS)

Suran, Swathi; Varma, Manoj

2018-02-01

Owing to its sensitivity and precise control at the nanoscale, polyelectrolytes have been immensely used to modify surfaces. Polyelectrolyte multilayers are generally water made and are easy to fabricate on any surface by the layer-by-layer (LbL) self-assembly process due to electrostatic interactions. Polyelectrolyte multilayers or PEMs can be assembled to form ultrathin membranes which can have potential applications in water filtration and desalination [1-3]. Hydration in PEMs is a consequence of both the bulk and surface phenomenon [4-7]. Bulk behavior of polymer membranes are well understood. Several techniques including reflectivity and contact angle measurements were used to measure the hydration in the bulk of polymer membranes [4, 8]. On the other hand their internal organization at the molecular level which can have a profound contribution in the transport mechanism, are not understood well. Previously, we engineered a technique, which we refer to as Bright-field Nanoscopy, which allows nanoscale optical imaging using local heterogeneities in a water-soluble germanium (Ge) thin film ( 25 nm thick) deposited on gold [8]. We use this technique to study the water transport in PEMs. It is understood that the surface charge and outer layers of the PEMs play a significant role in water transport through polymers [9-11]. This well-known `odd-even' effect arising on having different surface termination of the PEMs was optically observed with a spatial resolution unlike any other reported previously [12]. In this communication, we report that on increasing the etchant's concentration, one can control the lateral etching of the Ge film. This allowed the visualization of the nanoscale internal organization in the PEMs. Knowledge of the internal structure would allow one to engineer polymer membranes specific to applications such as drug delivering capsules, ion transport membranes and barriers etc. We also demonstrate a mathematical model involving a surface permeability term which captures the experimentally observed odd-even effect.

Fabrication and Characterization of Diffusion Bonds for Silicon Carbide

NASA Technical Reports Server (NTRS)

Halbig, Michael; Singh, Mrityunjay; Martin, Richard E.; Cosgriff, Laura M.

2007-01-01

Diffusion bonds of silicon carbide (SiC) were fabricated using several different types of titanium (Ti) based interlayers between the SiC substrates. The interlayers were an alloyed Ti foil, a pure Ti foil, and a physically vapor deposited (PVD) Ti coating. Microscopy was conducted to evaluate the cross-sections of the resulting bonds. Microprobe analysis identified reaction formed phases in the diffusion bonded region. Uniform and well adhered bonds were formed between the SiC substrates. In the case where the alloyed Ti foil or a thick Ti coating (i.e. 20 micron) was used as the interlayer, microcracks and several phases were present in the diffusion bonds. When a thinner interlayer was used (i.e. 10 micron PVD Ti), no microcracks were observed and only two reaction formed phases were present. The two phases were preferred and fully reacted phases that did not introduce thermal stresses or microcracks during the cool-down stage after processing. Diffusion bonded samples were evaluated with the non-destructive evaluation (NDE) methods of pulsed thermography and immersion ultrasonic testing. Joined SiC substrates that were fully bonded and that had simulated bond flaws in the interlayer were also evaluated using immersion ultrasound. Pull testing was conducted on the bonds to determine the tensile strength. To demonstrate the joining approach for a complex multilayered component for a low NOx injector application, the diffusion bonding approach was used to join three 4" diameter SiC discs that contained complex fuel and air flow channels.

Study of two different thin film coating methods in transmission laser micro-joining of thin Ti-film coated glass and polyimide for biomedical applications.

PubMed

Sultana, T; Georgiev, G L; Baird, R J; Auner, G W; Newaz, G; Patwa, R; Herfurth, H J

2009-07-01

Biomedical devices and implants require precision joining for hermetic sealing which can be achieved with low power lasers. The effect of two different thin metal film coating methods was studied in transmission laser micro-joints of titanium-coated glass and polyimide. The coating methods were cathodic arc physical vapor deposition (CA-PVD) and electron beam evaporation (EB-PVD). Titanium-coated glass joined to polyimide film can have neural electrode application. The improvement of the joint quality will be essential for robust performance of the device. Low power fiber laser (wave length = 1100 nm) was used for transmission laser micro-joining of thin titanium (Ti) film (approximately 200 nm) coated Pyrex borosilicate 7740 glass wafer (0.5 mm thick) and polyimide (Imidex) film (0.2 mm thick). Ti film acts as the coupling agent in the joining process. The Ti film deposition rate in the CA-PVD was 5-10 A/s and in the EB-PVD 1.5 A/s. The laser joint strength was measured by a lap shear test, the Ti film surfaces were analyzed by atomic force microscopy (AFM) and the lap shear tested joints were analyzed by optical microscopy and scanning electron microscopy (SEM). The film properties and the failure modes of the joints were correlated to joint strength. The CA-PVD produced around 4 times stronger laser joints than EB-PVD. The adhesion of the Ti film on glass by CA-PVD is better than that of the EB-PVD method. This is likely to be due to a higher film deposition rate and consequently higher adhesion or sticking coefficient for the CA-PVD particles arriving on the substrate compared to that of the EB-PVD film. EB-PVD shows poor laser bonding properties due to the development of thermal hotspots which occurs from film decohesion.

Disease-Related Microstructural Differences in the Brain in Women With Provoked Vestibulodynia.

PubMed

Gupta, Arpana; Woodworth, Davis C; Ellingson, Benjamin M; Rapkin, Andrea J; Naliboff, Bruce; Kilpatrick, Lisa A; Stains, Jean; Masghati, Salome; Tillisch, Kirsten; Mayer, Emeran A; Labus, Jennifer S

2018-05-01

Provoked vestibulodynia (PVD) is a chronic pelvic pain disorder affecting 16% of the female population. Neuroimaging studies have highlighted central abnormalities in PVD, similar to other chronic pelvic pain disorders, including brain regions involved in sensory processing and modulation of pain. The aim of the study was to determine alterations in the subvoxel, microstructural organization within tissues in PVD compared with healthy control participants (HCs) and a disease control group (irritable bowel syndrome [IBS]). Diffusion tensor imaging magnetic resonance imaging was conducted in 87 age-matched premenopausal women (29 PVD, 29 HCs, 29 IBS). Statistical parameter mapping of fractional anisotropy (FA) and mean diffusivity (MD) maps were used to identify microstructural difference in the brain specific to PVD or shared with IBS. PVD alterations in microstructural organization of the brain were predominantly observed in fibers associated with sensorimotor integration and pain processing that relay information between the thalamus, basal ganglia, sensorimotor, and insular cortex. PVD, compared with HCs, showed extensive increases in the FA of somatosensory and basal ganglia regions. In contrast, PVD and IBS subjects did not show any FA-related group differences. PVD subjects showed greater MD in the basal ganglia compared with HCs (higher MD in the internal capsule and pallidum) and IBS (higher MD in the putamen and pallidum). Increases in MD were associated with increased vaginal muscle tenderness and vulvar pain. The current findings highlight possible shared mechanisms between 2 different pelvic pain disorders, but also highlight the widespread alterations observed specifically in PVD compared with HCs. Alterations in microstructure in PVD were observed in fibers associated with sensorimotor integration and pain processing, which were also associated with increased vaginal muscle tenderness and vulvar pain. These alterations may be contributing to increased pain sensitivity and tenderness, highlighting the need for new therapies targeting the central nervous system. Copyright © 2018 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Clinical trials in peripheral vascular disease: pipeline and trial designs: an evaluation of the ClinicalTrials.gov database.

PubMed

Subherwal, Sumeet; Patel, Manesh R; Chiswell, Karen; Tidemann-Miller, Beth A; Jones, W Schuyler; Conte, Michael S; White, Christopher J; Bhatt, Deepak L; Laird, John R; Hiatt, William R; Tasneem, Asba; Califf, Robert M

2014-11-11

Tremendous advances have occurred in therapies for peripheral vascular disease (PVD); until recently, however, it has not been possible to examine the entire clinical trial portfolio of studies for the treatment of PVD (both arterial and venous disease). We examined interventional trials registered in ClinicalTrials.gov from October 2007 through September 2010 (n=40,970) and identified 676 (1.7%) PVD trials (n=493 arterial only, n=170 venous only, n=13 both arterial and venous). Most arterial studies investigated lower-extremity peripheral artery disease and acute stroke (35% and 24%, respectively), whereas most venous studies examined deep vein thrombosis/pulmonary embolus prevention (42%) or venous ulceration (25%). A placebo-controlled trial design was used in 27% of the PVD trials, and 4% of the PVD trials excluded patients >65 years of age. Enrollment in at least 1 US site decreased from 51% of trials in 2007 to 41% in 2010. Compared with noncardiology disciplines, PVD trials were more likely to be double-blinded, to investigate the use of devices and procedures, and to have industry sponsorship and assumed funding source, and they were less likely to investigate drug and behavioral therapies. Geographic access to PVD clinical trials within the United States is limited to primarily large metropolitan areas. PVD studies represent a small group of trials registered in ClinicalTrials.gov, despite the high prevalence of vascular disease in the general population. This low number, compounded by the decreasing number of PVD trials in the United States, is concerning and may limit the ability to inform current clinical practice of patients with PVD. © 2014 American Heart Association, Inc.

Synthesis, iron(III) complexation properties, molecular dynamics simulations and P. aeruginosa siderophore-like activity of two pyoverdine analogs.

PubMed

Antonietti, Viviane; Boudesocque, Stéphanie; Dupont, Laurent; Farvacques, Natacha; Cézard, Christine; Da Nascimento, Sophie; Raimbert, Jean-François; Socrier, Larissa; Robin, Thierry-Johann; Morandat, Sandrine; El Kirat, Karim; Mullié, Catherine; Sonnet, Pascal

2017-09-08

P. aeruginosa ranks among the top five organisms causing nosocomial infections. Among the many novel strategies for developing new therapeutics against infection, targeting iron uptake mechanism seems promising as P. aeruginosa needs iron for its growth and survival. To scavenge iron, the bacterium produces siderophores possessing a very high affinity towards Fe(III) ions such as pyoverdines. In this work, we decided to study two pyoverdine analogs, aPvd2 and aPvd3, structurally close to the endogen pyoverdine. The pFe constants calculated with the values of formation showed a high affinity of aPvd3 towards Fe(III). Molecular dynamics calculations demonstrated that aPvd3-Fe forms with Fe(III) stable 1:1 complexes in water, whereas aPvd2 does not. Only aPvd3 is able to increase the bacterial growth and represents thus an alternative to pyoverdine for iron acquisition by the bacterium. The aPvd2-3 interaction studies with a lipid membrane indicated that they were unable to interact and to cross the plasma membrane of bacteria by passive diffusion. Consequently, the penetration of aPvd3 is ruled by a transport membrane protein. These results showed that aPvd3 may be used to inhibit pyoverdine uptake or to promote the accumulation and release of antibiotics into the cell following a Trojan horse strategy. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Thermal barrier coating life prediction model development, phase 2

NASA Technical Reports Server (NTRS)

Meier, Susan Manning; Sheffler, Keith D.; Nissley, David M.

1991-01-01

The objective of this program was to generate a life prediction model for electron-beam-physical vapor deposited (EB-PVD) zirconia thermal barrier coating (TBC) on gas turbine engine components. Specific activities involved in development of the EB-PVD life prediction model included measurement of EB-PVD ceramic physical and mechanical properties and adherence strength, measurement of the thermally grown oxide (TGO) growth kinetics, generation of quantitative cyclic thermal spallation life data, and development of a spallation life prediction model. Life data useful for model development was obtained by exposing instrumented, EB-PVD ceramic coated cylindrical specimens in a jet fueled burner rig. Monotonic compression and tensile mechanical tests and physical property tests were conducted to obtain the EB-PVD ceramic behavior required for burner rig specimen analysis. As part of that effort, a nonlinear constitutive model was developed for the EB-PVD ceramic. Spallation failure of the EB-PVD TBC system consistently occurred at the TGO-metal interface. Calculated out-of-plane stresses were a small fraction of that required to statically fail the TGO. Thus, EB-PVD spallation was attributed to the interfacial cracking caused by in-plane TGO strains. Since TGO mechanical properties were not measured in this program, calculation of the burner rig specimen TGO in-plane strains was performed by using alumina properties. A life model based on maximum in-plane TGO tensile mechanical strain and TGO thickness correlated the burner rig specimen EB-PVD ceramic spallation lives within a factor of about plus or minus 2X.

UKPDS 59: hyperglycemia and other potentially modifiable risk factors for peripheral vascular disease in type 2 diabetes.

PubMed

Adler, Amanda I; Stevens, Richard J; Neil, Andrew; Stratton, Irene M; Boulton, Andrew J M; Holman, Rury R

2002-05-01

To determine the role of hyperglycemia in prospective analyses of peripheral vascular disease (PVD) in type 2 diabetes, taking into account other potential risk factors. Potential risk factors for the development of PVD were examined in 3,834 of 5,102 individuals enrolled in the U.K. Prospective Diabetes Study (UKPDS) without PVD at diagnosis of diabetes, followed for 6 years, and for whom relevant data were available. PVD was defined as two of the following: ankle-arm blood pressure index < 0.8, absence of both dorsalis pedis and posterior tibial pulses to palpation in one or both legs, and intermittent claudication. Logistic regression was used to estimate the association between potential risk factors measured 3-4 months after diagnosis of diabetes and incident PVD. The prevalence of PVD at 3-year intervals to 18 years was determined. Hyperglycemia, assessed as HbA(1c), was associated with an increased risk for incident PVD, independent of other risk factors including age, increased systolic blood pressure, reduced HDL cholesterol, smoking, prior cardiovascular disease, peripheral sensory neuropathy, and retinopathy. Each 1% increase in HbA(1c) was associated with a 28% increased risk of PVD (95% CI 12-46), and each 10-mmHg increase in systolic blood pressure with a 25% increase in risk (95% CI 10-43). Hyperglycemia, as well as smoking, dyslipidemia, and blood pressure are potentially modifiable risk factors for the development of PVD.

Effect of pyoverdine supply on cadmium and nickel complexation and phytoavailability in hydroponics.

PubMed

Ferret, C; Cornu, J Y; Elhabiri, M; Sterckeman, T; Braud, A; Jezequel, K; Lollier, M; Lebeau, T; Schalk, I J; Geoffroy, V A

2015-02-01

Siderophores are chelators with a high selectivity for Fe(III) and a good affinity for divalent metals, including Cd(II) and Ni(II). Inoculation with siderophore-producing bacteria (SPB) has thus been proposed as an alternative to chelator supply in phytoremediation. Accurate assessments of the potential of this association require a dissection of the interaction of siderophores with metals at the soil-root interface. This study focuses on pyoverdine (Pvd), the main siderophore produced by Pseudomonas aeruginosa. We first assessed the ability of Pvd to coordinate Ni(II). The stability constant of Pvd-Ni(II) (log K (L'Ni) = 10.9) was found to be higher than that of Pvd-Cd(II) (log K (L'Cd) = 8.2). We then investigated the effect of a direct supply of Pvd on the mobilization, speciation, and phytoavailability of Cd and Ni in hydroponics. When supplied at a concentration of 50 μM, Pvd selectively promoted Ni mobilization from smectite. It decreased plant Ni and Cd contents and the free ionic fractions of these two metals, consistent with the free ion activity model. Pvd had a more pronounced effect for Ni than for Cd, as predicted from its coordination properties. Inoculation with P. aeruginosa had a similar effect on Ni phytoavailability to the direct supply of Pvd.

Improvement of laser molecular beam epitaxy grown SrTiO3 thin film properties by temperature gradient modulation growth

NASA Astrophysics Data System (ADS)

Li, Jin Long; Hao, J. H.; Li, Y. R.

2007-09-01

Oxygen diffusion at the SrTiO3/Si interface was analyzed. A method called temperature gradient modulation growth was introduced to control oxygen diffusion at the interface of SrTiO3/Si. Nanoscale multilayers were grown at different temperatures at the initial growing stage of films. Continuous growth of SrTiO3 films was followed to deposit on the grown sacrificial layers. The interface and crystallinity of SrTiO3/Si were investigated by in situ reflection high energy electron diffraction and x-ray diffraction measurements. It has been shown that the modulated multilayers may help suppress the interfacial diffusion, and therefore improve SrTiO3 thin film properties.

Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

DOE PAGES

Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth R.; ...

2016-02-05

Here, we developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray's superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioningmore » it.« less

Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

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

Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth R.

Here, we developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray's superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioningmore » it.« less

Gate-tunable diode-like current rectification and ambipolar transport in multilayer van der Waals ReSe2/WS2 p-n heterojunctions.

PubMed

Wang, Cong; Yang, Shengxue; Xiong, Wenqi; Xia, Congxin; Cai, Hui; Chen, Bin; Wang, Xiaoting; Zhang, Xinzheng; Wei, Zhongming; Tongay, Sefaattin; Li, Jingbo; Liu, Qian

2016-10-12

Vertically stacked van der Waals (vdW) heterojunctions of two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted a great deal of attention due to their fascinating properties. In this work, we report two important gate-tunable phenomena in new artificial vdW p-n heterojunctions created by vertically stacking p-type multilayer ReSe 2 and n-type multilayer WS 2 : (1) well-defined strong gate-tunable diode-like current rectification across the p-n interface is observed, and the tunability of the electronic processes is attributed to the tunneling-assisted interlayer recombination induced by majority carriers across the vdW interface; (2) the distinct ambipolar behavior under gate voltage modulation both at forward and reverse bias voltages is found in the vdW ReSe 2 /WS 2 heterojunction transistors and a corresponding transport model is proposed for the tunable polarity behaviors. The findings may provide some new opportunities for building nanoscale electronic and optoelectronic devices.

Epitaxy: Programmable Atom Equivalents Versus Atoms

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

Wang, Mary X.; Seo, Soyoung E.; Gabrys, Paul A.

The programmability of DNA makes it an attractive structure-directing ligand for the assembly of nanoparticle superlattices in a manner that mimics many aspects of atomic crystallization. However, the synthesis of multilayer single crystals of defined size remains a challenge. Though previous studies considered lattice mismatch as the major limiting factor for multilayer assembly, thin film growth depends on many interlinked variables. Here, a more comprehensive approach is taken to study fundamental elements, such as the growth temperature and the thermodynamics of interfacial energetics, to achieve epitaxial growth of nanoparticle thin films. Under optimized equilibrium conditions, single crystal, multilayer thin filmsmore » can be synthesized over 500 × 500 μm2 areas on lithographically patterned templates. Importantly, these superlattices follow the same patterns of crystal growth demonstrated in thin film atomic deposition, allowing for these processes to be understood in the context of well-studied atomic epitaxy, and potentially enabling a nanoscale model to study fundamental crystallization processes.« less

Design of radiation resistant metallic multilayers for advanced nuclear systems

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

Zhernenkov, Mikhail, E-mail: zherne@bnl.gov, E-mail: gills@bnl.gov; Gill, Simerjeet, E-mail: zherne@bnl.gov, E-mail: gills@bnl.gov; Stanic, Vesna

2014-06-16

Helium implantation from transmutation reactions is a major cause of embrittlement and dimensional instability of structural components in nuclear energy systems. Development of novel materials with improved radiation resistance, which is of the utmost importance for progress in nuclear energy, requires guidelines to arrive at favorable parameters more efficiently. Here, we present a methodology that can be used for the design of radiation tolerant materials. We used synchrotron X-ray reflectivity to nondestructively study radiation effects at buried interfaces and measure swelling induced by He implantation in Cu/Nb multilayers. The results, supported by transmission electron microscopy, show a direct correlation betweenmore » reduced swelling in nanoscale multilayers and increased interface area per unit volume, consistent with helium storage in Cu/Nb interfaces in forms that minimize dimensional changes. In addition, for Cu/Nb layers, a linear relationship is demonstrated between the measured depth-dependent swelling and implanted He density from simulations, making the reflectivity technique a powerful tool for heuristic material design.« less

Enhanced photocatalytic hydrogen production on three-dimensional gold butterfly wing scales/CdS nanoparticles

NASA Astrophysics Data System (ADS)

Fang, Jing; Song, Guofen; Liu, Qinglei; Zhang, Wang; Gu, Jiajun; Su, Yishi; Su, Huilan; Guo, Cuiping; Zhang, Di

2018-01-01

Photocatalytic water splitting via utilizing various semiconductors is recognized as a promising way for hydrogen production. Plasmonic metals with sub-micrometer textures can improve the photocatalytic performance of semiconductors via a localized surface plasmon resonance (LSPR) process. Moreover, arrays of multilayer metallic structures can help generate strong LSPR. However, artificial synthesis has difficulties in constructing novel multilayer metallic arrays down to nanoscales. Here, we use three dimensional (3D) scales from Morpho didius forewings (M) to prepare 3D Au-wings with intact hierarchical bio-structures. For comparison, we use Troides helena forewings (T) which are known for their antireflection quasi-honeycomb structures resulting in strong light absorbing ability. Results show that multilayer rib structures of Au-M can significantly amplify the LSPR of 3D Au and thus can efficiently help the photocatalytic process (9-fold increase). This amplification effect is obviously more superior to the straightforward enhancement of the absorption of incident light (Au-T, 5-fold increase). Thus, our study provides the possibility to prepare highly efficient plasmonic photocatalysts (possessing 3D multilayer rib structures) via an easy method. This work will also be revealing for plasmonic applications in other fields.

Capacity and Delay Spread in Multilayer Diffusion-Based Molecular Communication (DBMC) Channel.

PubMed

Md Mustam, Saizalmursidi; Syed-Yusof, Sharifah K; Zubair, Suleiman

2016-10-01

In nanoscale communication, diffusion-based molecular communication (DBMC) in which information is encoded into molecule patterns by a transmitter nanomachine, has emerged as a promising communication system, particularly for biomedical and healthcare applications. Although, numerous studies have been conducted to evaluate and analyze DBMC systems, investigation on DBMC system through a multilayer channel has received less attention. The aims of this paper are to formulate channel characteristics and to evaluate the performance of multilayer DBMC channel in terms of delay spread and capacity. In this paper, the propagation of molecules over an n- layer channel is assumed to follow the Brownian motion and subjected to Fick's law of diffusion. Fourier transform is used to convert time to frequency domain functions. Besides, the multilayer channel is considered as a linear and deterministic channel. For the performance evaluation, the air-water-blood plasma medium representing the simplified multilayer diffusion model in the respiratory system was chosen. It was found that a high channel capacity can be achieved with wide transmission bandwidth, short transmission distance, and high averaged transmitted power. In addition, the findings showed that channel delay spread increases as both the transmission distance, and the pulse duration increased. By setting the symbol duration greater than the pulse duration or delay spread, an inter-symbol interference problem due to previous molecules transmission can be mitigated. These findings can be used as a guide in the development and fabrication of future artificial nanocommunication and nanonetworks systems involving multilayer transmission medium.

Incidence, Progression, and Associated Risk Factors of Posterior Vitreous Detachment in Type 2 Diabetes Mellitus: Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetic Study (SN-DREAMS II, Report No. 7).

PubMed

Gella, Laxmi; Raman, Rajiv; Pal, Swakshyar Saumya; Ganesan, Suganeswari; Sharma, Tarun

2017-01-01

To report the incidence and progression of posterior vitreous detachment (PVD) and factors influencing the same in a cohort of patients with type 2 diabetes in a South Indian population. A subset of 615 subjects from Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetics Study II were included in this study. All of the subjects underwent detailed ophthalmic evaluation including stereo fundus photography. The status of PVD was assessed using B-scan ultrasonography. A p value of <0.05 was considered statistically significant. The incidence of either incomplete PVD (IPVD) or complete PVD (CPVD) from no PVD at baseline visit was 80.8%. Of them, 32.63% converted to CPVD from IPVD at baseline. High prevalence of emmetropia was observed in subjects with stable No PVD. Risk factors associated with the conversion of CPVD from no PVD and IPVD at baseline were age (OR: 1.04, p = 0.002), myopia (OR: 2.14, p = 0.009), and increase in axial length (OR: 1.35, p = 0.004). Subjects undergoing cataract surgery were at 2.32 times higher risk of converting to CPVD (p = 0.038). Independent risk factors for the progression of PVD were increase in age, myopia, increased axial length, and cataract surgery.

Pseudomonas protegens Pf-5 favours self-produced siderophore over free-loading in interspecies competition for iron.

PubMed

Sexton, D Joseph; Glover, Rochelle C; Loper, Joyce E; Schuster, Martin

2017-09-01

Many microorganisms compete for extracellular iron using strain-specific chelators known as siderophores. The ferric-siderophore complex limits local access to iron because import requires a suitable cognate receptor. Interestingly, many species carry receptors that enable 'cross-feeding' on heterologous siderophores made by neighboring organisms, although little is known about how this ubiquitous behaviour is regulated. Here, we investigated the soil bacterium Pseudomonas protegens Pf-5, a strain remarkable for its ability to use dozens of heterologous siderophores. We characterized the expression of six pyoverdine-type (PVD) siderophore receptors in response to their cognate PVD. In general, we found expression is tightly regulated to reflect availability of their cognate PVD. In contrast, Pf-5 continues to secrete its own primary siderophore, PVD Pf-5 , despite the capability and opportunity to cross-feed. We demonstrate that this strategy is beneficial in co-culture with a competing PVD PAO1 -producer, P. aeruginosa PAO1. Although Pf-5 can cross-feed on PVD PAO1 , production of PVD Pf-5 is required to maintain a competitive advantage. We attribute this to an antagonistic effect of PVD Pf-5 on the growth of PAO1, presumably through limiting access to iron. Our results demonstrate the benefits of excluding competitors out-weigh the incentives associated with a free-loader lifestyle for Pf-5. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Deformation Mechanism Map of Cu/Nb Nanoscale Metallic Multilayers as a Function of Temperature and Layer Thickness

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

Snel, J.; Monclús, M. A.; Castillo-Rodríguez, M.

The mechanical properties and deformation mechanisms of Cu/Nb nanoscale metallic multilayers (NMMs) manufactured by accumulative roll bonding are studied at 25°C and 400°C. Cu/Nb NMMs with individual layer thicknesses between 7 nm and 63 nm were tested by in situ micropillar compression inside a scanning electron microscope. Yield strength, strain-rate sensitivities and activation volumes were obtained from the pillar compression tests. The deformed micropillars were examined under scanning and transmission electron microscopy in order to examine the deformation mechanisms active for different layer thicknesses and temperatures. The paper suggests that room temperature deformation was determined by dislocation glide at largermore » layer thicknesses and interface-related mechanisms at the thinner layer thicknesses. The high-temperature compression tests, in contrast, revealed superior thermo-mechanical stability and strength retention for the NMMs with larger layer thicknesses with deformation controlled by dislocation glide. A remarkable transition in deformation mechanism occurred as the layer thickness decreased, to a deformation response controlled by diffusion processes along the interfaces, which resulted in temperature-induced softening. Finally, a deformation mechanism map, in terms of layer thickness and temperature, is proposed from the results obtained in this investigation.« less

Deformation Mechanism Map of Cu/Nb Nanoscale Metallic Multilayers as a Function of Temperature and Layer Thickness

DOE PAGES

Snel, J.; Monclús, M. A.; Castillo-Rodríguez, M.; ...

2017-08-29

The mechanical properties and deformation mechanisms of Cu/Nb nanoscale metallic multilayers (NMMs) manufactured by accumulative roll bonding are studied at 25°C and 400°C. Cu/Nb NMMs with individual layer thicknesses between 7 nm and 63 nm were tested by in situ micropillar compression inside a scanning electron microscope. Yield strength, strain-rate sensitivities and activation volumes were obtained from the pillar compression tests. The deformed micropillars were examined under scanning and transmission electron microscopy in order to examine the deformation mechanisms active for different layer thicknesses and temperatures. The paper suggests that room temperature deformation was determined by dislocation glide at largermore » layer thicknesses and interface-related mechanisms at the thinner layer thicknesses. The high-temperature compression tests, in contrast, revealed superior thermo-mechanical stability and strength retention for the NMMs with larger layer thicknesses with deformation controlled by dislocation glide. A remarkable transition in deformation mechanism occurred as the layer thickness decreased, to a deformation response controlled by diffusion processes along the interfaces, which resulted in temperature-induced softening. Finally, a deformation mechanism map, in terms of layer thickness and temperature, is proposed from the results obtained in this investigation.« less

Secondary provoked vestibulodynia in sexually active women with uncomplicated recurrent urinary tract infections.

PubMed

Salonia, Andrea; Clementi, Maria Chiara; Graziottin, Alessandra; Nappi, Rossella E; Castiglione, Fabio; Ferrari, Matteo; Capitanio, Umberto; Damiano, Rocco; Montorsi, Francesco

2013-09-01

Uncomplicated recurrent urinary tract infections (rUTIs) associated with uropathogenic Escherichia coli (UPEC) are common among healthy, reproductive-aged women. Provoked vestibulodynia (PVD) is a major reason of sexual pain in premenopausal women. The aim of this paper is to assess prevalence and predictors of secondary PVD in a cohort of Caucasian-European, heterosexual, sexually active, reproductive-aged women seeking medical help for rUTIs as their primary complaint. Clinical and psychometric variables for 60 consecutive patients with rUTIs were considered. Patients were assessed with a thorough medical and sexual history, a number of psychometric instruments, and a specific physical examination. Urinalysis and self-collected urine cultures from the previous 12 months were also examined. Descriptive statistics and logistic regression models were used to test the associations between secondary PVD and sociodemographic and clinical variables. Mean age was 34.2 years (median 33 years; range 21-42). Secondary PVD was found in 36 of 60 patients (60%). Women with PVD had a higher prevalence of urinary tract infections (UTIs) over the previous 12 months (χ(2) : 4.54; P = 0.03) and suffered more frequently from UPEC-related rUTIs (χ(2) : 5.92; P = 0.01) than those without PVD. Moreover, women with PVD showed significantly lower scores on Female Sexual Function Index domains (all P ≤ 0.01), as compared with PVD-negative women. UPEC-related rUTIs (odds ratio [OR]: 3.1; P = 0.01), six or more UTIs over the previous 12 months (OR: 2.8; P = 0.01), and treatment with three or more antibiotics throughout the same period (OR: 2.1; P = 0.04) emerged as independent predictors of PVD. Three of five Caucasian-European, heterosexual, sexually active women of reproductive age complaining of rUTIs as their primary disorder also suffer from secondary PVD. Uncomplicated UPEC-related rUTIs are more frequently associated with secondary PVD than are UTIs caused by different uropathogens. © 2013 International Society for Sexual Medicine.

Pain, psychological distress and motor pattern in women with provoked vestibulodynia (PVD) - symptom characteristics and therapy suggestions.

PubMed

Haugstad, Gro Killi; Wojniusz, Slawomir; Kirste, Unni Merete; Kirschner, Rolf Steinar; Lilleheie, Ingvild; Haugstad, Tor Sigbjørn

2018-04-25

Provoked vestibulodynia (PVD) represent a longstanding pain syndrome that affects large numbers of women worldwide. However, no standardized guidelines for PVD treatment exist. In a cross-sectional pilot study we examined 30 PVD patients on multidimensional parameters including pain, psychological distress and quality of movement, in order to obtain a broader understanding of the somatic and psychological symptoms in PVD, and for the future to develop better interventions. Additionally, we compare the findings to previously published results regarding the same parameters in women with chronic pelvic pain (CPP). Thirty women with PVD recruited from a tertiary care university clinic of gynecology were assessed for demographic data, pain intensity (VAS), psychological distress (GHQ-30 and Tampa scale of Kinesophobia) and quality of movement (standardized Mensendieck test, SMT). Average age of the PVD women was 24.7±3.60 years, 60% of them were in permanent relationships, all were nulliparous, none had been subjected to surgical procedures, 100% were working full or part time and 90% were educated to at least undergraduate level. Mean VAS score was 7.77±1.97 (mean±SD), kinesiophobia 24.4±3.95 and anxiety domain of GHQ-30 9.73±4.06. SMT scores were particularly low for the domains of respiration and gait (less than 50% of optimal scores). PVD women display reduced quality of movement, especially for gait and respiration patterns, increased level of anxiety and high average pain scores. These findings are similar to what we have previously reported in CPP patients. However, in contrast to CPP group, PVD women are on average younger, have higher work participation, higher education level and have not been subjected to surgical procedures. Since PVD women display similar, although somewhat less severe, symptom profile than CPP, we suggest that a multidimensional approach to treatment, such as "somatocognitive therapy" should be investigated in this group as it has previously been shown to be promising in treatment of CPP.

Nanoscale Origins of Ferroelastic Domain Wall Mobility in Ferroelectric Multilayers

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

Huang, Hsin-Hui; Hong, Zijian; Xin, Huolin L.

Here we investigate the nanoscale origins of ferroelastic domain wall motion in ferroelectric multilayer thin films that lead to giant electromechanical responses. We present direct evidence for complex underpinning factors that result in ferroelastic domain wall mobility using a combination of atomic-level aberration corrected scanning transmission electron microscopy and phase-field simulations in model epitaxial (001) tetragonal (T) PbZr xTi 1-xO 3 (PZT)/rhombohedral (R) PbZr xTi 1-xO 3 (PZT) bilayer heterostructures. The local electric dipole distribution is imaged on an atomic scale for a ferroelastic domain wall that nucleates in the R-layer and cuts through the composition breaking the T/R interface.more » Our studies reveal a highly complex polarization rotation domain structure that is nearly on the knife-edge at the vicinity of this wall. Induced phases, namely tetragonal-like and rhombohedral-like monoclinic were observed close to the interface, and exotic domain arrangements, such as a half-four-fold closure structure, are observed. Phase field simulations show this is due to the minimization of the excessive elastic and electrostatic energies driven by the enormous strain gradient present at the location of the ferroelastic domain walls. Thus, in response to an applied stimulus, such as an electric field, any polarization reorientation must minimize the elastic and electrostatic discontinuities due to this strain gradient, which would induce a dramatic rearrangement of the domain structure. This insight into the origins of ferroelastic domain wall motion will allow researchers to better “craft” such multilayered ferroelectric systems with precisely tailored domain wall functionality and enhanced sensitivity, which can be exploited for the next generation of integrated piezoelectric technologies.« less

Dielectrophoretic trapping of multilayer DNA origami nanostructures and DNA origami-induced local destruction of silicon dioxide.

PubMed

Shen, Boxuan; Linko, Veikko; Dietz, Hendrik; Toppari, J Jussi

2015-01-01

DNA origami is a widely used method for fabrication of custom-shaped nanostructures. However, to utilize such structures, one needs to controllably position them on nanoscale. Here we demonstrate how different types of 3D scaffolded multilayer origamis can be accurately anchored to lithographically fabricated nanoelectrodes on a silicon dioxide substrate by DEP. Straight brick-like origami structures, constructed both in square (SQL) and honeycomb lattices, as well as curved "C"-shaped and angular "L"-shaped origamis were trapped with nanoscale precision and single-structure accuracy. We show that the positioning and immobilization of all these structures can be realized with or without thiol-linkers. In general, structural deformations of the origami during the DEP trapping are highly dependent on the shape and the construction of the structure. The SQL brick turned out to be the most robust structure under the high DEP forces, and accordingly, its single-structure trapping yield was also highest. In addition, the electrical conductivity of single immobilized plain brick-like structures was characterized. The electrical measurements revealed that the conductivity is negligible (insulating behavior). However, we observed that the trapping process of the SQL brick equipped with thiol-linkers tended to induce an etched "nanocanyon" in the silicon dioxide substrate. The nanocanyon was formed exactly between the electrodes, that is, at the location of the DEP-trapped origami. The results show that the demonstrated DEP-trapping technique can be readily exploited in assembling and arranging complex multilayered origami geometries. In addition, DNA origamis could be utilized in DEP-assisted deformation of the substrates onto which they are attached. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoscale Origins of Ferroelastic Domain Wall Mobility in Ferroelectric Multilayers

DOE PAGES

Huang, Hsin-Hui; Hong, Zijian; Xin, Huolin L.; ...

2016-10-31

Here we investigate the nanoscale origins of ferroelastic domain wall motion in ferroelectric multilayer thin films that lead to giant electromechanical responses. We present direct evidence for complex underpinning factors that result in ferroelastic domain wall mobility using a combination of atomic-level aberration corrected scanning transmission electron microscopy and phase-field simulations in model epitaxial (001) tetragonal (T) PbZr xTi 1-xO 3 (PZT)/rhombohedral (R) PbZr xTi 1-xO 3 (PZT) bilayer heterostructures. The local electric dipole distribution is imaged on an atomic scale for a ferroelastic domain wall that nucleates in the R-layer and cuts through the composition breaking the T/R interface.more » Our studies reveal a highly complex polarization rotation domain structure that is nearly on the knife-edge at the vicinity of this wall. Induced phases, namely tetragonal-like and rhombohedral-like monoclinic were observed close to the interface, and exotic domain arrangements, such as a half-four-fold closure structure, are observed. Phase field simulations show this is due to the minimization of the excessive elastic and electrostatic energies driven by the enormous strain gradient present at the location of the ferroelastic domain walls. Thus, in response to an applied stimulus, such as an electric field, any polarization reorientation must minimize the elastic and electrostatic discontinuities due to this strain gradient, which would induce a dramatic rearrangement of the domain structure. This insight into the origins of ferroelastic domain wall motion will allow researchers to better “craft” such multilayered ferroelectric systems with precisely tailored domain wall functionality and enhanced sensitivity, which can be exploited for the next generation of integrated piezoelectric technologies.« less

Improved Thermal Cycling Durability of Thermal Barrier Coatings Manufactured by PS-PVD

NASA Astrophysics Data System (ADS)

Rezanka, S.; Mauer, G.; Vaßen, R.

2014-01-01

The plasma spray-physical vapor deposition (PS-PVD) process is a promising method to manufacture thermal barrier coatings (TBCs). It fills the gap between traditional thermal spray processes and electron beam physical vapor deposition (EB-PVD). The durability of PS-PVD manufactured columnar TBCs is strongly influenced by the compatibility of the metallic bondcoat (BC) and the ceramic TBC. Earlier investigations have shown that a smooth BC surface is beneficial for the durability during thermal cycling. Further improvements of the bonding between BC and TBC could be achieved by optimizing the formation of the thermally grown oxide (TGO) layer. In the present study, the parameters of pre-heating and deposition of the first coating layer were investigated in order to adjust the growth of the TGO. Finally, the durability of the PS-PVD coatings was improved while the main advantage of PS-PVD, i.e., much higher deposition rate in comparison to EB-PVD, could be maintained. For such coatings, improved thermal cycling lifetimes more than two times higher than conventionally sprayed TBCs, were measured in burner rigs at ~1250 °C/1050 °C surface/substrate exposure temperatures.

Assessment of a User Guide for One Semi-Automated Forces (OneSAF) Version 2.0

DTIC Science & Technology

2009-09-01

OneSAF uses a two-dimensional feature named a Plan View Display ( PVD ) as the primary graphical interface. The PVD replicates a map with a series...primary interface, the PVD is how the user watches the scenario unfold and requires the most interaction with the user. As seen in Table 3, all...participant indicated never using these seven map-related functions. Graphic control measures. Graphic control measures are applied to the PVD map to

Towards selecting the vagotomy and avoiding diarrhoea.

PubMed

Milewski, P J

1990-02-01

A retrospective review was carried out of 148 consecutive personal truncal vagotomies and anterior pylorectomies (TV + P), median follow-up 5.0 years. The recurrent ulcer rate was 6/148 (4.1%) for suspected (SRU) and 5/148 (3.4%) for proven ones (RU). This led to one death from RU. Thirty-six patients (24.3%) developed postvagotomy diarrhoea (PVD). Two of these were graded Visick IV because their occupations made PVD particularly inconvenient. These results are similar to those for TV and pyloroplasty, despite the slightly more destructive nature of pylorectomy. There were nine patients in whom evidence of associated bowel disease had been documented before or during operation. The occurrence of such evidence was significantly more frequent in the PVD group (6/36 vs. 3/112 patients, P = 0.014), suggesting either a summation of effects due to the bowel disease and the operation or that the diagnosis of PVD was sometimes incorrect. Of the six in the PVD group, two were in Visick Grade II because of their PVD, and four in Visick grade III or IV, but in one of these SRU was the main cause of the poor result, and in two the PVD was subsidiary to vomiting or dumping. One further patient in Visick III due to PVD had diverticular disease diagnosed after operation. Thus there were identifiable factors (occupation, associated bowel disorder) which could have been used to predict seven of the unsatisfactory results due partly or completely to PVD. TV + P is an effective operation for duodenal ulcer but, as with TV + pyloroplasty (though to no greater an extent), severe diarrhoea may occasionally mar the result.(ABSTRACT TRUNCATED AT 250 WORDS)

High heat flux properties of pure tungsten and plasma sprayed tungsten coatings

NASA Astrophysics Data System (ADS)

Liu, X.; Tamura, S.; Tokunaga, K.; Yoshida, N.; Noda, N.; Yang, L.; Xu, Z.

2004-08-01

High heat flux properties of pure tungsten and plasma sprayed tungsten coatings on carbon substrates have been studied by annealing and cyclic heat loading. The recrystallization temperature and an activation energy QR=126 kJ/mol for grain growth of tungsten coating by vacuum plasma spray (VPS) were estimated, and the microstructural changes of multi-layer tungsten and rhenium interface pre-deposited by physical vapor deposition (PVD) with anneal temperature were investigated. Cyclic load tests indicated that pure tungsten and VPS-tungsten coating could withstand 1000 cycles at 33-35 MW/m 2 heat flux and 3 s pulse duration, and inert gas plasma spray (IPS)-tungsten coating showed local cracks by 300 cycles but did not induce failure by further cycles. However, the failure of pure tungsten and VPS-tungsten coating by fatigue cracking was observed under higher heat load (55-60 MW/m 2) for 420 and 230 cycles, respectively.

Research and development of plasma sprayed tungsten coating on graphite and copper substrates

NASA Astrophysics Data System (ADS)

Liu, Xiang; Zhang, Fu; Tao, Shunyan; Cao, Yunzhen; Xu, Zengyu; Liu, Yong; Noda, N.

2007-06-01

Vacuum plasma sprayed tungsten coating on graphite and copper substrates has been prepared. VPS-W coated graphite has multilayered silicon and tungsten interface pre-deposited by physical vapor deposition (PVD) and VPS-W coated copper has graded transition interlayer. VPS-W coating was characterized, and then the high heat flux properties of the coating were examined. Experimental results indicated that both VPS-W coated graphite and VPS-W coated copper could endure 1000 cycles without visible failure under a heat flux of approximately 5 MW/m2 absorbed power density and 5 s pulse duration. A comparison between the present VPS-W coated graphite and VPS-W coated carbon fiber composite (CX-2002U) with Re interface made by Plansee Aktiengesllshaft was carried out. Results show that both Re and Si are suitable as intermediate layer for tungsten coating on carbon substrates.

Effects of intrauterine infusion of Escherichia coli lipopolysaccharide on uterine health, resolution of purulent vaginal discharge, and reproductive performance of lactating dairy cows.

PubMed

Moraes, João G N; Silva, Paula R B; Mendonça, Luís G D; Scanavez, Alexandre A; Silva, Joseane C C; Chebel, Ricardo C

2017-06-01

The objectives of the current experiment were to evaluate the effects of intrauterine infusion of Escherichia coli lipopolysaccharide (LPS) in cows diagnosed with purulent vaginal discharge (PVD) on intrauterine cell population, resolution of PVD, uterine health, and reproductive performance. Jersey cows (n = 3,084) were examined using the Metricheck device to diagnose PVD at 35 ± 6 d postpartum. Purulent vaginal discharge was defined as the presence of purulent (≥50% pus) discharge detectable in the vagina. Of the 310 cows positive for PVD, 267 cows were enrolled in the current experiment. To ensure proper timing of treatment and collection of samples, only 9 PVD-positive cows were treated per day. Selected cows were balanced at 35 ± 6 d postpartum for lactation number, body condition score, and milk yield and were randomly assigned to receive an intrauterine infusion of 20 mL of phosphate-buffered saline (PBS; control, n = 87), 20 mL of PBS with 150 µg LPS (LPS150, n = 91), or 20 mL of PBS with 300 µg of LPS (LPS300, n = 89). Uterine cytology was performed immediately before treatment and 1, 2, and 7 d after treatment to evaluate the effect of LPS treatment on intrauterine cell population. Cows were examined with the Metricheck device at 7 and 28 d after treatment to evaluate the effects of treatment on resolution of PVD. Reproductive status was recorded up to 200 d postpartum. Cows diagnosed with PVD had greater incidence of twinning, dystocia, retained placenta, and metritis after calving than cows without PVD. Count of polymorphonuclear leukocytes (PMNL) in uterine cytology 1, 2, and 7 d after intrauterine infusion was not statistically different among treatments. From d 0 to 1, however, PMNL count in uterine cytology of PBS cows increased by 5%, whereas the PMNL count in uterine cytology of LPS150 and LPS300 cows increased by 54 and 48%, respectively. Treatment did not affect the likelihood of cows being diagnosed with PVD 7 and 28 d after intrauterine infusion. Cows without PVD and LPS150 cows were more likely to be pregnant after the first postpartum AI than PBS cows. After the second postpartum AI, cows without PVD were more likely to be pregnant than PBS and LPS300 cows. Hazard of pregnancy up to 200 d postpartum was decreased for PBS and LPS300 cows compared with cows without PVD, and it tended to be decreased for LPS150 cows compared with cows without PVD. Intrauterine treatment with 150 µg of E. coli LPS of cows diagnosed with PVD improved likelihood of pregnancy after the first postpartum AI, but further research is needed to elucidate the mechanism by which LPS treatment improved fertility. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Fabrication of nanoscale heterostructures comprised of graphene-encapsulated gold nanoparticles and semiconducting quantum dots for photocatalysis.

PubMed

Li, Yuan; Chopra, Nitin

2015-05-21

Patterned growth of multilayer graphene shell encapsulated gold nanoparticles (GNPs) and their covalent linking with inorganic quantum dots are demonstrated. GNPs were grown using a xylene chemical vapor deposition process, where the surface oxidized gold nanoparticles catalyze the multilayer graphene shell growth in a single step process. The graphene shell encapsulating gold nanoparticles could be further functionalized with carboxylic groups, which were covalently linked to amine-terminated quantum dots resulting in GNP-quantum dot heterostructures. The compositions, morphologies, crystallinity, and surface functionalization of GNPs and their heterostructures with quantum dots were evaluated using microscopic, spectroscopic, and analytical methods. Furthermore, optical properties of the derived architectures were studied using both experimental methods and simulations. Finally, GNP-quantum dot heterostructures were studied for photocatalytic degradation of phenol.

Morphology evolution in strain-compensated multiple quantum well structures

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

Ledentsov, N. N., E-mail: nikolay.ledentsov@v-i-systems.com; Shchukin, V. A.; Rouvimov, S.

2014-01-20

Morphology evolution in (In,Ga)As-Ga(As,P) strain-compensated multilayer structures is studied. The effects of nanoscale interface corrugation and phase separation are evident after the third period of the multilayer structure and become more pronounced with each new stack until the sixth period. Then, the interface stabilizes pointing to the formation of strain-balanced equilibrium interface structure. The epitaxial structure remains defect-free up to the maximum number (twenty) of periods studied. In a structure with a high lattice mismatch between the neighboring layers, In{sub 0.40}Ga{sub 0.60}As/GaAs{sub 0.85}P{sub 0.15}, clusters of dislocations are revealed already in the third period. The observed phenomena are critical formore » proper engineering of optoelectronic devices.« less

Nanoscale strategies: treatment for peripheral vascular disease and critical limb ischemia.

PubMed

Tu, Chengyi; Das, Subhamoy; Baker, Aaron B; Zoldan, Janeta; Suggs, Laura J

2015-01-01

Peripheral vascular disease (PVD) is one of the most prevalent vascular diseases in the U.S. afflicting an estimated 8 million people. Obstruction of peripheral arteries leads to insufficient nutrients and oxygen supply to extremities, which, if not treated properly, can potentially give rise to a severe condition called critical limb ischemia (CLI). CLI is associated with extremely high morbidities and mortalities. Conventional treatments such as angioplasty, atherectomy, stent implantation and bypass surgery have achieved some success in treating localized macrovascular disease but are limited by their invasiveness. An emerging alternative is the use of growth factor (delivered as genes or proteins) and cell therapy for PVD treatment. By delivering growth factors or cells to the ischemic tissue, one can stimulate the regeneration of functional vasculature network locally, re-perfuse the ischemic tissue, and thus salvage the limb. Here we review recent advance in nanomaterials, and discuss how their application can improve and facilitate growth factor or cell therapies. Specifically, nanoparticles (NPs) can serve as drug carrier and target to ischemic tissues and achieve localized and sustained release of pro-angiogenic proteins. As nonviral vectors, NPs can greatly enhance the transfection of target cells with pro-angiogenic genes with relatively fewer safety concern. Further, NPs may also be used in combination with cell therapy to enhance cell retention, cell survival and secretion of angiogenic factors. Lastly, nano/micro fibrous vascular grafts can be engineered to better mimic the structure and composition of native vessels, and hopefully overcome many complications/limitations associated with conventional synthetic grafts.

Prevalence of posterior vitreous detachment in glaucoma patients and controls.

PubMed

Schwab, Christoph; Glatz, Wilfried; Schmidt, Bernd; Lindner, Ewald; Oettl, Karl; Riedl, Regina; Wedrich, Andreas; Ivastinovic, Domagoj; Velikay-Parel, Michaela; Mossboeck, Georg

2017-05-01

To evaluate the impact of oxidative stress - present in glaucoma - on the vitreous. We therefore compare the presence of early and late stages of posterior vitreous detachment (PVD) between patients with glaucoma and controls. The vitreous state was evaluated by the combination of optical coherence tomography and ultrasound. The main outcome was the vitreous state classified into 'no PVD', 'initial PVD' and 'advanced PVD'. We evaluated the vitreous state in 48 patients with glaucoma (age: mean 66.5 ± 11.9 years; visual field deviation: mean 10.4 ± 6.8 dB) and compared the results with 101 previously investigated controls (age: mean 73.6 ± 9.3 years). After one-to-one matching on age and sex, ordinal logistic regression revealed that patients with glaucoma were significantly more likely to exhibit advanced PVD stages compared to non-glaucoma patients (OR 2.60, 95% confidence interval: 1.06-6.36, p = 0.037). Our results suggest that the presence or absence of PVD might be a valuable hint for diagnosing glaucoma - however, further research is needed to determine whether PVD can be used to supplement current glaucoma screening guidelines. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Impact of educational seminars on women with provoked vestibulodynia.

PubMed

Brotto, Lori A; Sadownik, Leslie; Thomson, Sydney

2010-02-01

Provoked vestibulodynia (PVD) is a common genital pain condition characterized by severe pain upon vaginal penetration. The treatment of women with PVD suggests variable efficacy across modalities. The emotional toll of PVD, because of the intimate and interpersonal nature of this sexually-provoked pain, and the relationship between PVD and anxiety, depression, and a host of subclinical emotional symptoms that may interfere with treatment, has been well documented. The role of the gynaecologist in identifying and managing these psychological symptoms has never been addressed. The goal of this study was to examine the efficacy of a brief, gynaecologist-led educational seminar on measures of psychological symptoms and sexual health. Twenty-nine women with PVD participated in three one-hour educational seminars led by a gynaecologist with expertise in the management of PVD. Participants completed questionnaires before, immediately after, and six months after the third session. There were significant improvements in psychological symptoms of depression, anxiety, somatization, hostility, paranoid ideation, psychoticism, and the global severity index, both immediately post-seminar and at the six-month follow-up. Sexual arousal, orgasm, overall sexual function, and sexual distress also significantly improved in response to the seminars. Gynaecologist-led educational seminars delivered in a group format have a significant positive impact on psychological symptoms and sexual functioning in women who suffer from PVD.

Plasma Spray-PVD: A New Thermal Spray Process to Deposit Out of the Vapor Phase

NASA Astrophysics Data System (ADS)

von Niessen, Konstantin; Gindrat, Malko

2011-06-01

Plasma spray-physical vapor deposition (PS-PVD) is a low pressure plasma spray technology recently developed by Sulzer Metco AG (Switzerland). Even though it is a thermal spray process, it can deposit coatings out of the vapor phase. The basis of PS-PVD is the low pressure plasma spraying (LPPS) technology that has been well established in industry for several years. In comparison to conventional vacuum plasma spraying (VPS) or low pressure plasma spraying (LPPS), the new proposed process uses a high energy plasma gun operated at a reduced work pressure of 0.1 kPa (1 mbar). Owing to the high energy plasma and further reduced work pressure, PS-PVD is able to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats but also by vaporizing the injected material. Therefore, the PS-PVD process fills the gap between the conventional physical vapor deposition (PVD) technologies and standard thermal spray processes. The possibility to vaporize feedstock material and to produce layers out of the vapor phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and electron beam-physical vapor deposition (EB-PVD) coatings. In contrast to EB-PVD, PS-PVD incorporates the vaporized coating material into a supersonic plasma plume. Owing to the forced gas stream of the plasma jet, complex shaped parts such as multi-airfoil turbine vanes can be coated with columnar thermal barrier coatings using PS-PVD. Even shadowed areas and areas which are not in the line of sight of the coating source can be coated homogeneously. This article reports on the progress made by Sulzer Metco in developing a thermal spray process to produce coatings out of the vapor phase. Columnar thermal barrier coatings made of Yttria-stabilized Zircona (YSZ) are optimized to serve in a turbine engine. This process includes not only preferable coating properties such as strain tolerance and erosion resistance but also the simultaneous coverage of multiple air foils.

Can Fear, Pain, and Muscle Tension Discriminate Vaginismus from Dyspareunia/Provoked Vestibulodynia? Implications for the New DSM-5 Diagnosis of Genito-Pelvic Pain/Penetration Disorder.

PubMed

Lahaie, Marie-Andrée; Amsel, Rhonda; Khalifé, Samir; Boyer, Stephanie; Faaborg-Andersen, Marie; Binik, Yitzchak M

2015-08-01

Fear has been suggested as the crucial diagnostic variable that may distinguish vaginismus from dyspareunia. Unfortunately, this has not been systematically investigated. The primary purpose of this study, therefore, was to investigate whether fear as evaluated by subjective, behavioral, and psychophysiological measures could differentiate women with vaginismus from those with dyspareunia/provoked vestibulodynia (PVD) and controls. A second aim was to re-examine whether genital pain and pelvic floor muscle tension differed between vaginismus and dyspareunia/PVD sufferers. Fifty women with vaginismus, 50 women with dyspareunia/PVD, and 43 controls participated in an experimental session comprising a structured interview, pain sensitivity testing, a filmed gynecological examination, and several self-report measures. Results demonstrated that fear and vaginal muscle tension were significantly greater in the vaginismus group as compared to the dyspareunia/PVD and no-pain control groups. Moreover, behavioral measures of fear and vaginal muscle tension were found to discriminate the vaginismus group from the dyspareunia/PVD and no-pain control groups. Genital pain did not differ significantly between the vaginismus and dyspareunia/PVD groups; however, genital pain was found to discriminate both clinical groups from controls. Despite significant statistical differences on fear and vaginal muscle tension variables between women suffering from vaginismus and dyspareunia/PVD, a large overlap was observed between these conditions. These findings may explain the great difficulty health professionals experience in attempting to reliably differentiate vaginismus from dyspareunia/PVD. The implications of these data for the new DSM-5 diagnosis of Genito-Pelvic Pain/Penetration Disorder are discussed.

Galaxy and Mass Assembly (GAMA): small-scale anisotropic galaxy clustering and the pairwise velocity dispersion of galaxies

NASA Astrophysics Data System (ADS)

Loveday, J.; Christodoulou, L.; Norberg, P.; Peacock, J. A.; Baldry, I. K.; Bland-Hawthorn, J.; Brown, M. J. I.; Colless, M.; Driver, S. P.; Holwerda, B. W.; Hopkins, A. M.; Kafle, P. R.; Liske, J.; Lopez-Sanchez, A. R.; Taylor, E. N.

2018-03-01

The galaxy pairwise velocity dispersion (PVD) can provide important tests of non-standard gravity and galaxy formation models. We describe measurements of the PVD of galaxies in the Galaxy and Mass Assembly (GAMA) survey as a function of projected separation and galaxy luminosity. Due to the faint magnitude limit (r < 19.8) and highly complete spectroscopic sampling of the GAMA survey, we are able to reliably measure the PVD to smaller scales (r⊥ = 0.01 h - 1 Mpc) than previous work. The measured PVD at projected separations r⊥ ≲ 1 h - 1 Mpc increases near monotonically with increasing luminosity from σ12 ≈ 200 km s - 1 at Mr = -17 mag to σ12 ≈ 600 km s - 1 at Mr ≈ -22 mag. Analysis of the Gonzalez-Perez et al. (2014) GALFORM semi-analytic model yields no such trend of PVD with luminosity: the model overpredicts the PVD for faint galaxies. This is most likely a result of the model placing too many low-luminosity galaxies in massive haloes.

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

Economy, David Ross; Mara, Nathan A.; Schoeppner, R.

In complex loading conditions (e.g. sliding contact), mechanical properties, such as strain hardening and initial hardness, will dictate the long-term performance of materials systems. With this in mind, the strain hardening behaviors of Cu/Nb nanoscale metallic multilayer systems were examined by performing nanoindentation tests within nanoscratch wear boxes and undeformed, as-deposited regions. Both the architecture and substrate influence were examined by utilizing three different individual layer thicknesses (2, 20, and 100 nm) and two total film thicknesses (1 and 10 μm). After nano-wear deformation, multilayer systems with thinner layers showed less volume loss as measured by laser scanning microscopy. Additionally,more » the hardness of the deformed regions significantly rose with respect to the as-deposited measurements, which further increased with greater wear loads. Strain hardening exponents for multilayers with thinner layers (2 and 20 nm, n ≈ 0.018 and n ≈ 0.022 respectively) were less than was determined for 100 nm systems (n ≈ 0.041). These results suggest that singledislocation based deformation mechanisms observed for the thinner systems limit the extent of achievable strain hardening. This conclusion indicates that impacts of both architecture strengthening and strain hardening must be considered to accurately predict multilayer performance during sliding contact across varying length scales.« less

PvdQ Quorum Quenching Acylase Attenuates Pseudomonas aeruginosa Virulence in a Mouse Model of Pulmonary Infection

PubMed Central

Utari, Putri D.; Setroikromo, Rita; Melgert, Barbro N.; Quax, Wim J.

2018-01-01

Pseudomonas aeruginosa is the predominant pathogen in pulmonary infections associated with cystic fibrosis. Quorum sensing (QS) systems regulate the production of virulence factors and play an important role in the establishment of successful P. aeruginosa infections. Inhibition of the QS system (termed quorum quenching) renders the bacteria avirulent thus serving as an alternative approach in the development of novel antibiotics. Quorum quenching in Gram negative bacteria can be achieved by preventing the accumulation of N-acyl homoserine lactone (AHL) signaling molecule via enzymatic degradation. Previous work by us has shown that PvdQ acylase hydrolyzes AHL signaling molecules irreversibly, thereby inhibiting QS in P. aeruginosa in vitro and in a Caenorhabditis elegans model of P. aeruginosa infection. The aim of the present study is to assess the therapeutic efficacy of intranasally instilled PvdQ acylase in a mouse model of pulmonary P. aeruginosa infection. First, we evaluated the deposition pattern of intranasally administered fluorochrome-tagged PvdQ (PvdQ-VT) in mice at different stages of pulmonary infection by in vivo imaging studies. Following intranasal instillation, PvdQ-VT could be traced in all lung lobes with 42 ± 7.5% of the delivered dose being deposited at 0 h post-bacterial-infection, and 34 ± 5.2% at 72 h post bacterial-infection. We then treated mice with PvdQ during lethal P. aeruginosa pulmonary infection and that resulted in a 5-fold reduction of lung bacterial load and a prolonged survival of the infected animals with the median survival time of 57 hin comparison to 42 h for the PBS-treated group. In a sublethal P. aeruginosa pulmonary infection, PvdQ treatment resulted in less lung inflammation as well as decrease of CXCL2 and TNF-α levels at 24 h post-bacterial-infection by 15 and 20%, respectively. In conclusion, our study has shown therapeutic efficacy of PvdQ acylase as a quorum quenching agent during P. aeruginosa infection. PMID:29755959

Identification of type II and type III pyoverdine receptors from Pseudomonas aeruginosa.

PubMed

de Chial, Magaly; Ghysels, Bart; Beatson, Scott A; Geoffroy, Valérie; Meyer, Jean Marie; Pattery, Theresa; Baysse, Christine; Chablain, Patrice; Parsons, Yasmin N; Winstanley, Craig; Cordwell, Stuart J; Cornelis, Pierre

2003-04-01

Pseudomonas aeruginosa produces, under conditions of iron limitation, a high-affinity siderophore, pyoverdine (PVD), which is recognized at the level of the outer membrane by a specific TonB-dependent receptor, FpvA. So far, for P. aeruginosa, three different PVDs, differing in their peptide chain, have been described (types I-III), but only the FpvA receptor for type I is known. Two PVD-producing P. aeruginosa strains, one type II and one type III, were mutagenized by a mini-TnphoA3 transposon. In each case, one mutant unable to grow in the presence of the strong iron chelator ethylenediaminedihydroxyphenylacetic acid (EDDHA) and the cognate PVD was selected. The first mutant, which had an insertion in the pvdE gene, upstream of fpvA, was unable to take up type II PVD and showed resistance to pyocin S3, which is known to use type II FpvA as receptor. The second mutant was unable to take up type III PVD and had the transposon insertion in fpvA. Cosmid libraries of the respective type II and type III PVD wild-type strains were constructed and screened for clones restoring the capacity to grow in the presence of PVD. From the respective complementing genomic fragments, type II and type III fpvA sequences were determined. When in trans, type II and type III fpvA restored PVD production, uptake, growth in the presence of EDDHA and, in the case of type II fpvA, pyocin S3 sensitivity. Complementation of fpvA mutants obtained by allelic exchange was achieved by the presence of cognate fpvA in trans. All three receptors posses an N-terminal extension of about 70 amino acids, similar to FecA of Escherichia coli, but only FpvAI has a TAT export sequence at its N-terminal end.

Performance of Ti-multilayer coated tool during machining of MDN431 alloyed steel

NASA Astrophysics Data System (ADS)

Badiger, Pradeep V.; Desai, Vijay; Ramesh, M. R.

2018-04-01

Turbine forgings and other components are required to be high resistance to corrosion and oxidation because which they are highly alloyed with Ni and Cr. Midhani manufactures one of such material MDN431. It's a hard-to-machine steel with high hardness and strength. PVD coated insert provide an answer to problem with its state of art technique on the WC tool. Machinability studies is carried out on MDN431 steel using uncoated and Ti-multilayer coated WC tool insert using Taguchi optimisation technique. During the present investigation, speed (398-625rpm), feed (0.093-0.175mm/rev), and depth of cut (0.2-0.4mm) varied according to Taguchi L9 orthogonal array, subsequently cutting forces and surface roughness (Ra) were measured. Optimizations of the obtained results are done using Taguchi technique for cutting forces and surface roughness. Using Taguchi technique linear fit model regression analysis carried out for the combination of each input variable. Experimented results are compared and found the developed model is adequate which supported by proof trials. Speed, feed and depth of cut are linearly dependent on the cutting force and surface roughness for uncoated insert whereas Speed and depth of cut feed is inversely dependent in coated insert for both cutting force and surface roughness. Machined surface for coated and uncoated inserts during machining of MDN431 is studied using optical profilometer.

Characterization and cell behavior of titanium surfaces with PLL/DNA modification via a layer-by-layer technique.

PubMed

Gao, Wenli; Feng, Bo; Lu, Xiong; Wang, Jianxin; Qu, Shuxin; Weng, Jie

2012-08-01

This study describes the fabrication of two types of multilayered films onto titanium by layer-by-layer (LBL) self-assembly, using poly-L-lysine (PLL) as the cationic polyelectrolyte and deoxyribonucleic acid (DNA) as the anionic polyelectrolyte. The assembling process of each component was studied using atomic force microscopy (AFM) and quartz crystal balance (QCM). Zeta potential of the LBL-coated microparticles was measured by dynamic light scattering. Titanium substrates with or without multilayered films were used in osteoblast cell culture experiments to study cell proliferation, viability, differentiation, and morphology. Results of AFM and QCM indicated the progressive build-up of the multilayered coatings. The surface morphology of three types of multilayered films showed elevations in the nanoscale range. The data of zeta potential showed that the surface terminated with PLL displayed positive charge while the surface terminated with DNA displayed negative charge. The proliferation of osteoblasts on modified titanium films was found to be greater than that on control (p < 0.05) after 3 and 7 days culture, respectively. Alamar blue measurement showed that the PLL/DNA-modified films have higher cell viability (p < 0.05) than the control. Still, the alkaline phosphatase activity assay revealed a better differentiated phenotype on three types of multilayered surfaces compared to noncoated controls. Collectively our results suggest that PLL/DNA were successfully used to surface engineer titanium via LBL technique, and enhanced its cell biocompatibility. Copyright © 2012 Wiley Periodicals, Inc.

Effectiveness of intrauterine treatment with cephapirin in dairy cows with purulent vaginal discharge.

PubMed

Tison, N; Bouchard, E; DesCôteaux, L; Lefebvre, R C

2017-02-01

The objective of this study was to assess the efficacy of cephapirin intrauterine treatment preceding a timed artificial insemination protocol in lactating dairy cows with purulent vaginal discharges (PVDs). Holstein dairy cows (n = 1247) from 18 herds were enrolled in a controlled randomized clinical trial. At 34 days in milk (DIM; ±7 days), cows had a genital examination (transrectal palpation, vaginoscopy, and uterine bacteriology). They were randomly assigned to either the control group (CONT, no treatment) or the treatment group (CEPH) consisting of 1 intrauterine infusion of 500-mg cephapirin benzathine (RCL) (Metricure, Merck Animal Health, Montreal, Canada) regardless of the uterine health status. All cows were systematically enrolled in a presynch-ovsynch protocol for the first insemination. A second genital examination was made 2 weeks later. Cows that received any systemic or local antibiotics 10 days prior sampling to the end of the synchronization protocol were excluded from the study. Reproductive data of cows were collected for at least 300 DIM, entered in a databank, and validated (health record management software, DSAHR). Pregnancy diagnosis was done by transrectal palpation at the routinely scheduled veterinarian visits. On the basis of the highest sum of sensibility and specificity for pregnancy status at 120 DIM, the optimal cutoff for vaginal discharge score was determined as the presence of cloudy discharge with or without purulent material (PVD+, score 2). With a prevalence of 21.6% at 34 DIM, PVD+ was detrimental to the first-service conception rate (FSCR; PVD+: 26 ± 5%; PVD-: 40 ± 3%; P = 0.02). The negative effect of PVD+ was indicated by a hazard ratio of 0.72 (chi-square = 8.58; P < 0.01; 95% confidence interval = 0.56-0.91). Treatment with cephapirin was associated with a significant improvement of the FSCR in PVD+ cows (PVD+ CEPH: 36 ± 5%, PVD+ CONT: 23 ± 5%; P < 0.05), although it did not produce a considerable clinical cure based on the second examination. Thus, a longer period of time following treatment may be needed to properly assess the efficacy of intrauterine treatment in PVD+ cows. In conclusion, cephapirin intrauterine treatment in PVD+ cows at 34 DIM considerably improves reproductive performance compared with untreated PVD+ cows. Copyright © 2016 Elsevier Inc. All rights reserved.

Prevalence of early and late stages of physiologic PVD in emmetropic elderly population.

PubMed

Schwab, Christoph; Ivastinovic, Domagoj; Borkenstein, Andreas; Lackner, Eva-Maria; Wedrich, Andreas; Velikay-Parel, Michaela

2012-05-01

To investigate the early and late stages of posterior vitreous detachment (PVD) in the foveal area in correlation with age and gender. Three hundred and thirty-five emmetropic eyes of 271 Caucasian patients (216 women/119 men) were examined by optical coherence tomography (OCT) and ultrasound (US). Eyes were classified into groups according to the patients age (up to 69.9; 70-74.9; 75-79.9; over 80 years) and to the clinical findings [Vitreous state: Detached in US; Detached in OCT; Foveal adhesion (FA); Attached vitreous]. The mean age was 76 ± 8 ranging from 44 to 89 years in female and 72 ± 10 ranging from 46 to 87 years in male subjects. The vitreous was attached in 32% of all eyes, 18.5% had FA, 18.5% were detached in OCT and 68% were detached in US. While prevalence of FA decreases with increasing age, OCT-diagnosed detachments did not change significantly with age. Between the ages of 70 and 75, an increase in PVD rates occurred. The prevalence of PVD was similar in both genders. Women were significantly older than men in the late-stage PVD in the eyes. The use of OCT and US enabled us to detect a partial or total PVD in 80% of the eyes. A sudden increase in late-stage PVD between the ages of 70 and 75 was observed, correlating with the reported age prevalence of various macular diseases. In contrast to myopics, both genders of elderly emmetropics have a similar prevalence of PVD. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

The Mendeleev-Meyer force project.

PubMed

Santos, Sergio; Lai, Chia-Yun; Amadei, Carlo A; Gadelrab, Karim R; Tang, Tzu-Chieh; Verdaguer, Albert; Barcons, Victor; Font, Josep; Colchero, Jaime; Chiesa, Matteo

2016-10-14

Here we present the Mendeleev-Meyer Force Project which aims at tabulating all materials and substances in a fashion similar to the periodic table. The goal is to group and tabulate substances using nanoscale force footprints rather than atomic number or electronic configuration as in the periodic table. The process is divided into: (1) acquiring nanoscale force data from materials, (2) parameterizing the raw data into standardized input features to generate a library, (3) feeding the standardized library into an algorithm to generate, enhance or exploit a model to identify a material or property. We propose producing databases mimicking the Materials Genome Initiative, the Medical Literature Analysis and Retrieval System Online (MEDLARS) or the PRoteomics IDEntifications database (PRIDE) and making these searchable online via search engines mimicking Pubmed or the PRIDE web interface. A prototype exploiting deep learning algorithms, i.e. multilayer neural networks, is presented.

Contrasting effects of pyoverdine on the phytoextraction of Cu and Cd in a calcareous soil.

PubMed

Cornu, J Y; Elhabiri, M; Ferret, C; Geoffroy, V A; Jezequel, K; Leva, Y; Lollier, M; Schalk, I J; Lebeau, T

2014-05-01

Enhanced metal phytoextraction by the use of siderophore-producing bacteria (SPB) has received a lot of attention in the past decade. Bacterial siderophores are able to bind a wide range of metals other than iron and thus should enhance their phytoavailability in contaminated matrices. However, the impact of bacterial siderophores in the soil-plant transfer of metals is not yet fully elucidated, as underlined by the opposing results reported in the literature regarding the efficiency of coupling phytoextraction with bioaugmentation by SPB. The present study focuses on one bacterial siderophore, the pyoverdine (Pvd), produced by Pseudomonas aeruginosa. The coordination properties of Pvd towards Cd(II) and Cu(II) were determined and the effect of Pvd supply was assessed on (i) the mobility (CaCl2 extractions), (ii) the phytoavailability (DGT measurements) and (iii) the phytoextraction of Cd and Cu, in a calcareous soil. The stability constant of Pvd-Cu (KL'Cu=10(20.1)) was found much higher than that of Pvd-Cd (KL'Cd=10(8.2)). The major finding was the agreement observed between Pvd coordination properties and Pvd impact on metals phytoextraction. Pyoverdine, supplied at 250 μmol kg(-1) soil, enhanced the mobility, the phytoavailability and the phytoextraction of Cu while the fate of Cd was not affected. All these results were compared to those reported for chelate-assisted phytoextraction. Their relevance in using SPB for phytoremediation is discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Properties of the carbon-palladium nanocomposites studied by Raman spectroscopy method

NASA Astrophysics Data System (ADS)

Belka, Radosław; Suchańska, Małgorzata

2013-10-01

In this paper, the results for thin carbon-palladium (C-Pd) nanocomposites obtained by PVD (Physical Vapour Deposition) and PVD/CVD (Chemical Vapour Deposition) method, carried out using Raman spectroscopy method are presented. Studies reveal the dominance of fullerene-like structure for PVD samples and graphite-like structures for CVD samples. The type of substrate and metal content have great impact on spectra shapes.

Report of Research at Technische Universitaet Darmstadt on Ultrahard Materials in the B-C-N-Si System

DTIC Science & Technology

2015-06-01

structure at the micro- and nanoscale. In other words, development of nanocomposites, multilayers, and superlattices via appropriate design and control of...C-B and C-N bonds as C-C and B-N bonds. Later, the same research group , based on first-principles total-energy, and dynamic phonon calculations...Vickers hardness values.7 Another research group employed an ab initio evolutionary algorithm42 to resolve the crystal structure of the observed

CHEMICAL SOLUTION DEPOSITION BASED OXIDE BUFFERS AND YBCO COATED CONDUCTORS

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

Paranthaman, Mariappan Parans

We have reviewed briefly the growth of buffer and high temperature superconducting oxide thin films using a chemical solution deposition (CSD) method. In the Rolling-Assisted Biaxially Textured Substrates (RABiTS) process, developed at Oak Ridge National Laboratory, utilizes the thermo mechanical processing to obtain the flexible, biaxially oriented copper, nickel or nickel-alloy substrates. Buffers and Rare Earth Barium Copper Oxide (REBCO) superconductors have been deposited epitaxially on the textured nickel alloy substrates. The starting substrate serves as a template for the REBCO layer, which has substantially fewer weak links. Buffer layers play a major role in fabricating the second generation REBCOmore » wire technology. The main purpose of the buffer layers is to provide a smooth, continuous and chemically inert surface for the growth of the REBCO film, while transferring the texture from the substrate to the superconductor layer. To achieve this, the buffer layers need to be epitaxial to the substrate, i.e. they have to nucleate and grow in the same bi-axial texture provided by the textured metal foil. The most commonly used RABiTS multi-layer architectures consist of a starting template of biaxially textured Ni-5 at.% W (Ni-W) substrate with a seed (first) layer of Yttrium Oxide (Y2O3), a barrier (second) layer of Yttria Stabilized Zirconia (YSZ), and a Cerium Oxide (CeO2) cap (third) layer. These three buffer layers are generally deposited using physical vapor deposition (PVD) techniques such as reactive sputtering. On top of the PVD template, REBCO film is then grown by a chemical solution deposition. This article reviews in detail about the list of oxide buffers and superconductor REBCO films grown epitaxially on single crystal and/or biaxially textured Ni-W substrates using a CSD method.« less

Analysis of influence of different pressure and different depth of pvd on soft foundation treatment

NASA Astrophysics Data System (ADS)

Li, Bin; Wang, XueKui

2018-02-01

According to the depth of plastic vertical drainage (pvd), the arrangement mode and the loading mode to analyze the influence of Vacuum preloading near the existing road. An arrangement mode of vacuum preloading to reduce the impact was put forward. The combination of different depth of pvd and loading modes are used to analyze the effect of vacuum preloading treatment and its influence range. The calculations show that the deformation and the influence distance are smaller by using the 40kPa vacuum loading and 41kPa surcharge load preloading. Reducing the depth of the pvd and vacuum combined surcharge preloading can weaken the influence to the existing highway.

Role of the vitreous in age-related macular degeneration.

PubMed

Ondeş, F; Yilmaz, G; Acar, M A; Unlü, N; Kocaoğlan, H; Arsan, A K

2000-01-01

To investigate the relationship between posterior vitreous detachment (PVD) and age-related macular degeneration (AMD). The condition of the vitreous was examined by slit-lamp funduscopy and ultrasonography in 93 eyes of 50 patients with AMD (exudative or dry) and 100 eyes of 50 controls. There was complete PVD in 31 of the 93 eyes (33.3%) of 50 patients with AMD and the posterior vitreous was attached in 62 of these eyes (66.6%). In the control group, in 50 eyes (50%) of 50 subjects there was posterior vitreous detachment. The prevalence of PVD in eyes with macular degeneration was significantly lower (P < .05). There was no statistically significant difference between the exudative and the nonexudative groups in respect to PVD. PVD may have a protective role against the development of AMD. Chronic vitreomacular traction and/or continuous exposure to free radicals and cytokines may possibly be one of the causes of AMD in eyes with attached vitreous.

Microstructural, mechanical and oxidation features of NiCoCrAlY coating produced by plasma activated EB-PVD

NASA Astrophysics Data System (ADS)

He, Jian; Guo, Hongbo; Peng, Hui; Gong, Shengkai

2013-06-01

NiCoCrAlY coatings produced by electron beam-physical vapor deposition (EB-PVD) have been extensively used as the oxidation resistance coatings or suitable bond coats in thermal barrier coating (TBC) system. However, the inherent imperfections caused by EB-PVD process degrade the oxidation resistance of the coatings. In the present work, NiCoCrAlY coatings were creatively produced by plasma activated electron beam-physical vapor deposition (PA EB-PVD). The novel coatings showed a terraced substructure on the surface of each grain due to the increased energy of metal ions and enhanced mobility of adatoms. Also a strong (1 1 1) crystallographic texture of γ/γ' grains was observed. The toughness of the coatings got remarkably improved compared with the coatings deposited by conventional EB-PVD and the oxidation behavior at 1373 K showed that the novel coatings had excellent oxidation resistance. The possible mechanism was finally discussed.

Elastase and matrix metalloproteinase activities are associated with pulmonary vascular disease in the nitrofen rat model of congenital diaphragmatic hernia.

PubMed

Wild, Benjamin; St-Pierre, Marie-Eve; Langlois, Stéphanie; Cowan, Kyle N

2017-05-01

Pulmonary vascular disease (PVD) is a leading cause of congenital diaphragmatic hernia (CDH) mortality. Progression of PVD involves extracellular matrix remodeling by elastases and matrix metalloproteinases (MMP), concomitant with proliferation of smooth muscle cells in a growth factor-enriched environment. Blockade of this pathway reversed primary pulmonary hypertension and improved survival. This study was designed to determine whether a similar pathway is induced in PVD secondary to CDH. Fetal rats exposed to nitrofen at gestational day 9 developed left-sided CDH and were compared at term to their non-CDH littermates by assessing histologic and biochemical features of PVD. Rats with CDH displayed right ventricle hypertrophy, increased pulmonary artery medial wall thickness and muscularization, and decreased lumen size. As revealed by in situ zymography and immunohistochemistry, this was associated with an induction of elastolytic and MMP activities as well as an elevation of epidermal growth factor and osteopontin levels in the diseased lung vasculature. CDH-associated PVD involves an induction of elastase and MMP activities and increased osteopontin deposition in an epidermal growth factor-rich environment. Inhibition of this pathway may thus represent a novel therapeutic approach for the treatment of CDH-associated PVD. Level I (Basic Science Study). Copyright © 2017 Elsevier Inc. All rights reserved.

Short- and long-latency auditory evoked potentials in individuals with vestibular dysfunction.

PubMed

Santos Filha, Valdete Alves Valentins Dos; Bruckmann, Mirtes; Garcia, Michele Vargas

2018-01-01

Purpose Evaluate the auditory pathway at the brainstem and cortical levels in individuals with peripheral vestibular dysfunction. Methods The study sample was composed 19 individuals aged 20-80 years that presented exam results suggestive of Peripheral Vestibular Disorder (PVD) or Vestibular Dysfunction (VD). Participants underwent evaluation of the auditory pathway through Brainstem Auditory Evoked Potentials (BAEP) (short latency) and P1, N1, P2, N2, and P300 cortical potentials (long latency). Results Nine individuals presented diagnosis of VD and 10 participants were diagnosed with PVD. The overall average of the long latency potentials of the participants was within the normal range, whereas an increased mean was observed in the short latency of waves III and V of the left ear, as well as in the I - III interpeak interval of both ears. Association of the auditory potentials with VD and PVD showed statistically significant correlation only in the III - V interpeak interval of the right ear for short latency. Comparison between the long and short latencies in the groups showed differences between VD and PVD, but without statistical significance. Conclusion No statistically significant correlation was observed between VD/PVD and the auditory evoked potentials; however, for the long latency potentials, individuals with VD presented higher latency in P1, N1, P2, and N2, where as participants with PVD showed higher latency in P300. In the short latency potentials, there was an increase in the absolute latencies in the VD group and in the interpeak intervals in the PVD group.

Carbon-based layer-by-layer nanostructures: from films to hollow capsules

NASA Astrophysics Data System (ADS)

Hong, Jinkee; Han, Jung Yeon; Yoon, Hyunsik; Joo, Piljae; Lee, Taemin; Seo, Eunyong; Char, Kookheon; Kim, Byeong-Su

2011-11-01

Over the past years, the layer-by-layer (LbL) assembly has been widely developed as one of the most powerful techniques to prepare multifunctional films with desired functions, structures and morphologies because of its versatility in the process steps in both material and substrate choices. Among various functional nanoscale objects, carbon-based nanomaterials, such as carbon nanotubes and graphene sheets, are promising candidates for emerging science and technology with their unique physical, chemical, and mechanical properties. In particular, carbon-based functional multilayer coatings based on the LbL assembly are currently being actively pursued as conducting electrodes, batteries, solar cells, supercapacitors, fuel cells and sensor applications. In this article, we give an overview on the use of carbon materials in nanostructured films and capsules prepared by the LbL assembly with the aim of unraveling the unique features and their applications of carbon multilayers prepared by the LbL assembly.

Transfer-free synthesis of multilayer graphene using a single-step process in an evaporator and formation confirmation by laser mode-locking.

PubMed

Kim, Won-Jun; Debnath, Pulak C; Lee, Junsu; Lee, Ju Han; Lim, Dae-Soon; Song, Yong-Won

2013-09-13

Multilayer graphene is synthesized by a simplified process employing an evaporator in which a target substrate is deposited with a Ni catalyst layer before being heated to grow graphene directly. Carbon atoms adsorbed onto the surface of the Ni source as impurities from the atmosphere are incorporated into the catalyst layer during the deposition, and diffuse toward the catalyst/substrate interface, where they crystallize as graphene with a thickness of less than 2 nm. The need for a transfer process and external carbon supply is eliminated. The graphene is characterized by conventional analysis approaches, including nano-scale visualization and Raman spectroscopy, and utilizing photonics, graphene-functionalized passive laser mode-locking is demonstrated to confirm the successful synthesis of the graphene layer, resulting in an operating center wavelength of 1569.4 nm, a pulse duration of 1.35 ps, and a repetition rate of 31.6 MHz.

Provoked Vestibulodynia: Does Pain Intensity Correlate With Sexual Dysfunction and Dissatisfaction?

PubMed

Aerts, Leen; Bergeron, Sophie; Pukall, Caroline F; Khalifé, Samir

2016-06-01

Provoked vestibulodynia (PVD) is suspected to be the most frequent cause of vulvodynia in premenopausal women. Previous research has been inconclusive as to whether higher vulvovaginal pain ratings are associated with lower sexual function and satisfaction in women with PVD. Whether pain intensity correlates with sexual impairment is an important question given its implications for treatment recommendations. To examine the associations among self-reported and objective pain measurements, sexual function, and sexual satisfaction in a large combined clinical and community sample of premenopausal women diagnosed with PVD. Ninety-eight women with PVD underwent a cotton-swab test, a vestibular friction pain measurement, and a vestibular pressure-pain threshold measurement. In addition to sociodemographics, participants completed measurements of pain, sexual function, and sexual satisfaction. Self-report measurements were the pain numerical rating scale (0-10), the McGill-Melzack Pain Questionnaire, the Female Sexual Function Index, and the Global Measure of Sexual Satisfaction. Objective measurements were pain during a cotton-swab test, pain during a vestibular friction procedure, and the vestibular pressure-pain threshold measurement. Age and relationship duration were significantly correlated with the Female Sexual Function Index total score (r = -0.31, P < .01; and r = -0.22, P < .05, respectively). When controlling for age, intercourse-related pain intensity, pain during the cotton-swab test, pain during vestibular friction, the vestibular pressure-pain threshold, and the McGill-Melzack Pain Questionnaire sensory and affective subscale scores were not significantly associated with sexual function and satisfaction in women with PVD. The findings show that in women with PVD, self-report and objective pain ratings are not associated with sexual function and satisfaction. The results support the biopsychosocial nature of PVD and underscore the importance of a patient-focused multidisciplinary treatment approach for PVD. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Comparison of vapor concentrations of volatile organic compounds with ground-water concentrations of selected contaminants in sediments beneath the Sudbury River, Ashland, Massachusetts, 2000

USGS Publications Warehouse

Campbell, J.P.; Lyford, F.P.; Willey, Richard E.

2002-01-01

A mixed plume of contaminants in ground water, including volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), and metals, near the former Nyanza property in Ashland, Massachusetts, discharges to the Sudbury River upstream and downstream of Mill Pond and a former mill raceway. Polyethylene-membrane vapor-diffusion (PVD) samplers were installed in river-bottom sediments to determine if PVD samplers provide an alternative to ground-water sampling from well points for identifying areas of detectable concentrations of contaminants in sediment pore water near the ground-water and surface-water interface. In August and September 2000, the PVD samplers were installed near well points at depths of 8 to 12 inches in both fine and coarse sediments, whereas the well points were installed at depths of 1 to 5 feet in coarse sediments only. Comparison between vapor and water samples at 29 locations upstream from Mill Pond show that VOC vapor concentrations from PVD samplers in coarse river-bottom sediments are more likely to correspond to ground-water concentrations from well points than PVD samplers installed in fine sediments. Significant correlations based on Kendall's Tau were shown between vapor and ground-water concentrations for trichloroethylene and chlorobenzene for PVD samplers installed in coarse sediments where the fine organic layer that separated the two sampling depths was 1 foot or less in thickness. VOC concentrations from vapor samples also were compared to VOC, SVOC, and metals concentrations from ground-water samples at 10 well points installed upstream and downstream from Mill Pond, and in the former mill raceway. Chlorobenzene vapor concentrations correlated significantly with ground-water concentrations for 5 VOCs, 2 SVOCs, and 10 metals. Trichloroethylene vapor concentrations did not correlate with any of the other ground-water constituents analyzed at the 10 well points. Chlorobenzene detected by use of PVD samplers appears to be a strong indicator of the presence of VOCs, SVOCs, and metals in ground water sampled from well points at this site. Results from PVD samplers indicate that contaminant concentrations in water from well points installed 1 to 5 ft below fine sediments may not reflect concentrations in pore water less than 1 foot below the river bottom. There is insufficient information available to determine if VOC concentrations detected in PVD samplers are useful for identifying detectable aqueous concentrations of SVOCs and metals in sediment pore water at this site. Samples of pore water from a similar depth as PVD samplers are needed for confirmation of this objective.

High Reflectance Nanoscale V/Sc Multilayer for Soft X-ray Water Window Region.

PubMed

Huang, Qiushi; Yi, Qiang; Cao, Zhaodong; Qi, Runze; Loch, Rolf A; Jonnard, Philippe; Wu, Meiyi; Giglia, Angelo; Li, Wenbin; Louis, Eric; Bijkerk, Fred; Zhang, Zhong; Wang, Zhanshan

2017-10-10

V/Sc multilayer is experimentally demonstrated for the first time as a high reflectance mirror for the soft X-ray water window region. It primarily works at above the Sc-L edge (λ = 3.11 nm) under near normal incidence while a second peak appears at above the V-L edge (λ = 2.42 nm) under grazing incidence. The V/Sc multilayer fabricated with a d-spacing of 1.59 nm and 30 bilayers has a smaller interface width (σ = 0.27 and 0.32 nm) than the conventional used Cr/Sc (σ = 0.28 and 0.47 nm). For V/Sc multilayer with 30 bilayers, the introduction of B 4 C barrier layers has little improvement on the interface structure. As the number of bilayers increasing to 400, the growth morphology and microstructure of the V/Sc layers evolves with slightly increased crystallization. Nevertheless, the surface roughness remains to be 0.25 nm. A maximum soft X-ray reflectance of 18.4% is measured at λ = 3.129 nm at 9° off-normal incidence using the 400-bilayers V/Sc multilayer. According to the fitted model, an s-polarization reflectance of 5.2% can also be expected at λ = 2.425 nm under 40° incidence. Based on the promising experimental results, further improvement of the reflectance can be achieved by using a more stable deposition system, exploring different interface engineering methods and so on.

Ta2O5/ Al2O3/ SiO2 - antireflective coating for non-planar optical surfaces by atomic layer deposition

NASA Astrophysics Data System (ADS)

Pfeiffer, K.; Schulz, U.; Tünnermann, A.; Szeghalmi, A.

2017-02-01

Antireflective coatings are essential to improve transmittance of optical elements. Most research and development of AR coatings has been reported on a wide variety of plane optical surfaces; however, antireflection is also necessary on nonplanar optical surfaces. Physical vapor deposition (PVD), a common method for optical coatings, often results in thickness gradients on strongly curved surfaces, leading to a failure of the desired optical function. In this work, optical thin films of tantalum pentoxide, aluminum oxide and silicon dioxide were prepared by atomic layer deposition (ALD), which is based on self-limiting surface reactions. The results demonstrate that ALD optical layers can be deposited on both vertical and horizontal substrate surfaces with uniform thicknesses and the same optical properties. A Ta2O5/Al2O3/ SiO2 multilayer AR coating (400-700 nm) was successfully applied to a curved aspheric glass lens with a diameter of 50 mm and a center thickness of 25 mm.

Self-assembly of dodecaphenyl POSS thin films

NASA Astrophysics Data System (ADS)

Handke, Bartosz; Klita, Łukasz; Niemiec, Wiktor

2017-12-01

The self-assembly abilities of Dodecaphenyl Polyhedral Oligomeric Silsesquioxane thin films on Si(1 0 0) surfaces were studied. Due to their thermal properties - relatively low sublimation temperature and preservation of molecular structure - cage type silsesquioxanes are ideal material for the preparation of a thin films by Physical Vapor Deposition. The Ultra-High Vacuum environment and the deposition precision of the PVD method enable the study of early stages of thin film growth and its molecular organization. X-ray Reflectivity and Atomic Force Microscopy measurements allow to pursuit size-effects in the structure of thin films with thickness ranges from less than a single molecular layer up to several tens of layers. Thermal treatment of the thin films triggered phase change: from a poorly ordered polycrystalline film into a well-ordered multilayer structure. Self-assembly of the layers is the effect of the π-stacking of phenyl rings, which force molecules to arrange in a superlattice, forming stacks of alternating organic-inorganic layers.

Addressing the challenges of phenotyping pediatric pulmonary vascular disease

PubMed Central

Goss, Kara N.; Everett, Allen D.; Mourani, Peter M.; Baker, Christopher D.; Abman, Steven H.

2017-01-01

Pediatric pulmonary vascular disease (PVD) and pulmonary hypertension (PH) represent phenotypically and pathophysiologically diverse disease categories, contributing substantial morbidity and mortality to a complex array of pediatric conditions. Here, we review the multifactorial nature of pediatric PVD, with an emphasis on improved recognition, phenotyping, and endotyping strategies for pediatric PH. Novel tailored approaches to diagnosis and treatment in pediatric PVD, as well as the implications for long-term outcomes, are highlighted. PMID:28680562

PVD-Beschichtungstechnologie

NASA Astrophysics Data System (ADS)

Lake, Markus K.

Die PVD-Technologie umfasst eine Reihe von Beschichtungsverfahren zur Abscheidung von Metallen, Legierungen oder chemischen Verbindungen durch Zufuhr von thermischer Energie oder durch Teilchenbeschuss im Hochvakuum. PVDVerfahren gestatten u. a. die Beschichtung bei niedrigen Prozesstemperaturen, so dass thermisch sensible Substrate, z. B. wärmebehandelte Stähle oder ausgewählte Kunststoffe, beschichtet werden können. Insbesondere mit dem Magnetron Sputter Ion Plating-Verfahren (MSIP-Verfahren) und mit dem Arc Ion Plating-Verfahren (AIP-Verfahren) ist es möglich, thermisch vorbehandelte Werkstoffe zu beschichten, ohne den eingestellten Wärmebehandlungszustand (Härte, Spannungszustand) zu verändern. Ferner können endbearbeitete Bauteile mit der PVD-Technologie beschichtet werden, da die eingesetzten PVD-Verfahren die Ausgangsoberfläche konturgetreu abbilden, ohne dass eine Nachbearbeitung erforderlich wird.

Substrate-induced interfacial plasmonics for photovoltaic conversion

PubMed Central

Li, Xinxi; Jia, Chuancheng; Ma, Bangjun; Wang, Wei; Fang, Zheyu; Zhang, Guoqing; Guo, Xuefeng

2015-01-01

Surface plasmon resonance (SPR) is widely used as light trapping schemes in solar cells, because it can concentrate light fields surrounding metal nanostructures and realize light management at the nanoscale. SPR in photovoltaics generally occurs at the metal/dielectric interfaces. A well-defined interface is therefore required to elucidate interfacial SPR processes. Here, we designed a photovoltaic device (PVD) with an atomically flat TiO2 dielectric/dye/graphene/metal nanoparticle (NP) interface for quantitatively studying the SPR enhancement of the photovoltaic conversion. Theoretical and experimental results indicated that the graphene monolayer was transparent to the electromagnetic field. This transparency led to significant substrate-induced plasmonic hybridization at the heterostructure interface. Combined with interparticle plasmonic coupling, the substrate-induced plasmonics concentrated light at the interface and enhanced the photo-excitation of dyes, thus improving the photoelectric conversion. Such a mechanistic understanding of interfacial plasmonic enhancement will further promote the development of efficient plasmon-enhanced solar cells and composite photocatalysts. PMID:26412576

Gramicidin ion channels in a lipid bilayer supported on polyelectrolyte multilayer films: an electrochemical impedance study.

PubMed

Diamanti, Eleftheria; Gutiérrez-Pineda, Eduart; Politakos, Nikolaos; Andreozzi, Patrizia; Rodriguez-Presa, María José; Knoll, Wolfgang; Azzaroni, Omar; Gervasi, Claudio A; Moya, Sergio E

2017-12-06

Supported membranes on polymer cushions are of fundamental interest as models for cell membranes. The use of polyelectrolyte multilayers (PEMs) assembled by the layer by layer (LbL) technique as supports for a bilayer allows for easy integration of the lipid bilayer on surfaces and devices and for nanoscale tunable spacing of the lipid bilayer. Controlling ionic permeability in lipid bilayers supported on PEMs triggers potential applications in sensing and as models for transport phenomena in cell membranes. Lipid bilayers displaying gramicidin channels are fabricated on top of polyallylamine hydrochloride (PAH) and polystyrene sulfonate (PSS) multilayer films, by the assembly of vesicles of phosphatidylcholine and phosphatidylserine, 50 : 50 M/M, carrying gramicidin (GA). Quartz crystal microbalance with dissipation shows that the vesicles with GA fuse into a bilayer. Atomic force microscopy reveals that the presence of GA alters the bilayer topography resulting in depressions in the bilayer of around 70 nm in diameter. Electrochemical impedance spectroscopy (EIS) studies show that supported bilayers carrying GA have smaller resistances than the bilayers without GA. Lipid layers carrying GA display a higher conductance for K + than for Na + and are blocked in the presence of Ca 2+ .

He+ ion irradiation response of Fe–TiO2 multilayers

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

Anderoglu, O.; Zhou, M. J.; Zhang, J.

2013-04-01

The accumulation of radiation-induced defect clusters and He bubble formation in He+ ion irradiated nanocrystalline TiO2 and Fe–TiO2 multilayer thin films were investigated using transmission electron microscopy (TEM). Prior to ion irradiation it was found that the crystallinity of TiO2 layers depends on the individual layer thickness: While all TiO2 layers are amorphous at 5 nm individual layer thickness, at 100 nm they are crystalline with a rutile polymorph. After He+ irradiation up to ~6 dpa at room temperature, amorphization of TiO2 layers was not observed in both nanocrystalline TiO2 single layers and Fe–TiO2 multilayers. The suppression of radiation-induced amorphizationmore » in TiO2 is interpreted in terms of a high density of defect sinks in these nano-composites in the form of Fe–TiO2 interphase boundaries and columnar grains within each layer with nano-scale intercolumnar porosity. In addition, a high concentration of He is believed to be trapped at these interfaces in the form of sub-nanometer-scale clusters retarding the formation of relatively larger He bubbles that can be resolved in TEM.« less

Dynamic study of Cr(VI) removal performance and mechanism from water using multilayer material coated nanoscale zerovalent iron.

PubMed

Wu, Bin; Peng, Dinghua; Hou, Siyu; Tang, Bicong; Wang, Can; Xu, Heng

2018-05-16

In this study, the dynamic Cr(VI) removal process from water by the synthesized multilayer material coated nanoscale zerovalent iron (SBC-nZVI) was systematically discussed at different treatment conditions. The results showed that initial pH, contact time, Cr(VI) concentration and the dosage of SBC-nZVI were important parameters that influenced the Cr(VI) removal efficiency. The major Cr(VI) removal occurred within 60 min and gradually tend to equilibrium with consistent treatment. The removal efficiency was highly depended on pH values and the adsorption kinetics agreed well with the pseduo-second-order model (PSO). When the initial Cr(VI) concentration was below 15 mg/L, the removal rate could reach to about 100%. Moreover, the removal efficiency increased with the increase of SBC-nZVI dosage, which related to the increase of reactive sites. To understand the removal mechanism, SBC-nZVI before and after reaction with Cr(VI) were characterized by fourier transform infrared spectra (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). These analysis showed that the interaction of SBC-nZVI with Cr(VI) was mainly controlled by reduction and electrostatic attraction. Therefore, these results explained the interaction between Cr(VI) and SBC-nZVI material in detail, and further proved that SBC-nZVI could be an effective material to remove Cr(VI) from water. Copyright © 2018. Published by Elsevier Ltd.

Interface structure in nanoscale multilayers near continuous-to-discontinuous regime

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

Pradhan, P. C.; Majhi, A.; Nayak, M., E-mail: mnayak@rrcat.gov.in

2016-07-28

Interfacial atomic diffusion, reaction, and formation of microstructure in nanoscale level are investigated in W/B{sub 4}C multilayer (ML) system as functions of thickness in ultrathin limit. Hard x-ray reflectivity (XRR) and x-ray diffuse scattering in conjunction with x-ray absorption near edge spectroscopy (XANES) in soft x-ray and hard x-ray regimes and depth profiling x-ray photoelectron spectroscopy (XPS) have been used to precisely evaluate detailed interfacial structure by systematically varying the individual layer thickness from continuous-to-discontinuous regime. It is observed that the interfacial morphology undergoes an unexpected significant modification as the layer thickness varies from continuous-to-discontinuous regime. The interfacial atomic diffusionmore » increases, the physical density of W layer decreases and that of B{sub 4}C layer increases, and further more interestingly the in-plane correlation length decreases substantially as the layer thickness varies from continuous-to-discontinuous regime. This is corroborated using combined XRR and x-ray diffused scattering analysis. XANES and XPS results show formation of more and more tungsten compounds at the interfaces as the layer thickness decreases below the percolation threshold due to increase in the contact area between the elements. The formation of compound enhances to minimize certain degree of disorder at the interfaces in the discontinuous region that enables to maintain the periodic structure in ML. The degree of interfacial atomic diffusion, interlayer interaction, and microstructure is correlated as a function of layer thickness during early stage of film growth.« less

Wear behaviour of wear-resistant adaptive nano-multilayered Ti-Al-Mo-N coatings

NASA Astrophysics Data System (ADS)

Sergevnin, V. S.; Blinkov, I. V.; Volkhonskii, A. O.; Belov, D. S.; Kuznetsov, D. V.; Gorshenkov, M. V.; Skryleva, E. A.

2016-12-01

Coating samples in the Ti-Al-Mo-N system were obtained by arc-PVD method at variable bias voltage Ub applied to the substrate, and the partial pressure of nitrogen P(N2) used as a reaction gas. The deposited coatings were characterized by a nanocrystalline structure with an average grain size of 30-40 nm and multilayered architecture with alternating layers of (Ti,Al)N nitride and Mo-containing phases with a thickness comparable to the grain size. Coatings of (Ti,Al)N-Mo-Mo2N and (Ti,Al)N-Mo2N compositions were obtained by changing deposition parameters. The obtained coatings had hardness of 40 GPa and the relative plastic deformation under microindentation up to 60%. (Ti,Al)N-Mo2N coatings demonstrated better physicomechanical characteristics, showing high resistance to crack formation and destruction through the plastic deformation mechanism without brittle fracturing, unlike (Ti,Al)N-Mo-Mo2N. The friction coefficient of the study coatings (against Al2O3 balls under dry condition using a pin-on-disc method) reached the values of 0.35 and 0.5 at 20 °C and 500 °C respectively, without noticeable wear within this temperature range. These tribological properties were achieved by forming MoO3 acting as a solid lubricant. At higher temperatures the deterioration in the tribological properties is due to the high rate of MoO3 sublimation from friction surfaces.

Purulent vaginal discharge in grazing dairy cows: Risk factors, reproductive performance, and prostaglandin F2α treatment.

PubMed

Giuliodori, M J; Magnasco, M; Magnasco, R P; Lacau-Mengido, I M; de la Sota, R L

2017-05-01

The objectives of this study were to assess the association of a 4-point scale of vaginal discharge score (VDS) with time to pregnancy to define criteria for a practical case of purulent vaginal discharge (PVD) in dairy cows, to test the risk factors for PVD, and, finally, the effect of a dose of PGF 2α on cure and reproductive performance. In experiment 1, grazing Holstein cows (n = 2,414) had their vaginal discharge scored at ∼32 d in milk (DIM) on a 4-point scale, the effect of VDS on the hazard of pregnancy by 300 DIM was then assessed to derive a case definition of PVD. Risk factors for PVD and self-cure were also assessed. In experiment 2, grazing Holstein cows (n = 6,326) from 5 herds were checked for PVD at ∼30 DIM. Cows with PVD were assigned to receive one dose of 500 μg of PGF 2α analog (Cloprostenol; Ciclase, Syntex SA, Buenos Aires, Argentina) per cow (odd ear tag number) or to remain untreated (even tag number). Cure was declared if cows presented clear normal vaginal discharge (VDS-0) at visit 2 (∼62 DIM). Data were analyzed with Cox's regression and mixed logistic models. In experiment 1, cows with VDS ≥1 had lower hazard of pregnancy and longer calving to pregnancy interval than cows with VDS-0. This finding was not affected by the time at which the diagnosis was performed. Therefore, a cow ≥21 DIM and having VDS ≥1 was used to define a case of PVD. The odds of PVD were greater in primiparous cows compared with multiparous, in cows with abnormal calving compared with those with normal calving, and in those losing BCS peripartum. In experiment 2, PGF 2α treatment tended to slightly increase the hazard of pregnancy (adjusted hazard ratio = 1.13). Conversely, PGF 2α had no effect on the odds of cure of PVD [adjusted odds ratio (AOR) = 1.19], pregnancy at first service (AOR = 1.03), or pregnancy by 100 DIM (AOR = 0.89) or 200 DIM (AOR = 1.27). In conclusion, cows with VDS ≥1 can be considered to have PVD because of their lower hazard of pregnancy and longer calving to pregnancy interval (up to 48 d). Important risk factors are parity, calving, and body condition score loss peripartum. Optimal time of diagnosis is ≥28 to 35 DIM because cows experience a high self-cure rate. Self-cure is also affected by parity, prepartum BCS, and VDS. Finally, as treatment with one dose of PGF 2α had a small effect on the hazard of pregnancy and no effect on clinical cure, its therapeutic use in grazing dairy cows with PVD is not recommended. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Anisotropic mechanoresponse of energetic crystallites: a quantum molecular dynamics study of nano-collision

NASA Astrophysics Data System (ADS)

Li, Ying; Kalia, Rajiv K.; Misawa, Masaaki; Nakano, Aiichiro; Nomura, Ken-Ichi; Shimamura, Kohei; Shimojo, Fuyuki; Vashishta, Priya

2016-05-01

At the nanoscale, chemistry can happen quite differently due to mechanical forces selectively breaking the chemical bonds of materials. The interaction between chemistry and mechanical forces can be classified as mechanochemistry. An example of archetypal mechanochemistry occurs at the nanoscale in anisotropic detonating of a broad class of layered energetic molecular crystals bonded by inter-layer van der Waals (vdW) interactions. Here, we introduce an ab initio study of the collision, in which quantum molecular dynamic simulations of binary collisions between energetic vdW crystallites, TATB molecules, reveal atomistic mechanisms of anisotropic shock sensitivity. The highly sensitive lateral collision was found to originate from the twisting and bending to breaking of nitro-groups mediated by strong intra-layer hydrogen bonds. This causes the closing of the electronic energy gap due to an inverse Jahn-Teller effect. On the other hand, the insensitive collisions normal to multilayers are accomplished by more delocalized molecular deformations mediated by inter-layer interactions. Our nano-collision studies provide a much needed atomistic understanding for the rational design of insensitive energetic nanomaterials and the detonation synthesis of novel nanomaterials.At the nanoscale, chemistry can happen quite differently due to mechanical forces selectively breaking the chemical bonds of materials. The interaction between chemistry and mechanical forces can be classified as mechanochemistry. An example of archetypal mechanochemistry occurs at the nanoscale in anisotropic detonating of a broad class of layered energetic molecular crystals bonded by inter-layer van der Waals (vdW) interactions. Here, we introduce an ab initio study of the collision, in which quantum molecular dynamic simulations of binary collisions between energetic vdW crystallites, TATB molecules, reveal atomistic mechanisms of anisotropic shock sensitivity. The highly sensitive lateral collision was found to originate from the twisting and bending to breaking of nitro-groups mediated by strong intra-layer hydrogen bonds. This causes the closing of the electronic energy gap due to an inverse Jahn-Teller effect. On the other hand, the insensitive collisions normal to multilayers are accomplished by more delocalized molecular deformations mediated by inter-layer interactions. Our nano-collision studies provide a much needed atomistic understanding for the rational design of insensitive energetic nanomaterials and the detonation synthesis of novel nanomaterials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08769d

Development of dye-sensitized solar cells composed of liquid crystal embedded, electrospun poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers as polymer gel electrolytes.

PubMed

Ahn, Sung Kwang; Ban, Taewon; Sakthivel, P; Lee, Jae Wook; Gal, Yeong-Soon; Lee, Jin-Kook; Kim, Mi-Ra; Jin, Sung-Ho

2012-04-01

In order to overcome the problems associated with the use of liquid electrolytes in dye-sensitized solar cells (DSSCs), a new system composed of liquid crystal embedded, polymer electrolytes has been developed. For this purpose, three types of DSSCs have been fabricated. The cells contain electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVdF-co-HFP) polymer gel electrolyte, with and without doping with the liquid crystal E7 and with a liquid electrolyte. The morphologies of the newly prepared DSSCs were explored using field emission scanning electron microscopy (FE-SEM). Analysis of the FE-SEM images indicate that the DSSC composed of E7 embedded on e-PVdF-co-HFP polymer gel electrolyte has a greatly regular morphology with an average diameter. The ionic conductivity of E7 embedded on e-PVdF-co-HFP polymer gel electrolyte was found to be 2.9 × 10(-3) S/cm at room temperature, a value that is 37% higher than that of e-PVdF-co-HFP polymer gel electrolyte. The DCCS containing the E7 embedded, e-PVdF-co-HFP polymer gel electrolyte was observed to possess a much higher power conversion efficiency (PCE = 6.82%) than that of an e-PVdF-co-HFP nanofiber (6.35%). In addition, DSSCs parameters of the E7 embedded, e-PVdF-co-HFP polymer gel electrolyte (V(oc) = 0.72 V, J(sc) = 14.62 mA/cm(2), FF = 64.8%, and PCE = 6.82% at 1 sun intensity) are comparable to those of a liquid electrolyte (V(oc) = 0.75 V, J(sc) = 14.71 mA/cm(2), FF = 64.9%, and PCE = 7.17%, both at a 1 sun intensity).

Assessment of risk of peripheral vascular disease and vascular care capacity in low- and middle-income countries.

PubMed

Gyedu, A; Stewart, B T; Nakua, E; Quansah, R; Donkor, P; Mock, C; Hardy, M; Yangni-Angate, K H

2016-01-01

This study aimed to describe national peripheral vascular disease (PVD) risk and health burden, and vascular care capacity in Ghana. The gap between PVD burden and vascular care capacity in low- and middle-income countries was defined, and capacity improvement priorities were identified. Data to estimate PVD risk factor burden were obtained from the World Health Organization Study on Global Ageing and Adult Health (SAGE), Ghana, and the Institute of Health Metrics and Evaluation Global Burden of Disease (IHME GBD) database. In addition, a novel nationwide assessment of vascular care capacity was performed, with 20 vascular care items assessed at 40 hospitals in Ghana. Factors contributing to specific item deficiency were described. From the SAGE database, there were 4305 respondents aged at least 50 years with data to estimate PVD risk. Of these, 57·4 per cent were at moderate to risk high of PVD with at least three risk factors; extrapolating nationally, the estimate was 1 654 557 people. Based on IHME GBD data, the estimated disability-adjusted life-years incurred from PVD increased fivefold from 1990 to 2010 (from 6·3 to 31·7 per 100 000 persons respectively). Vascular care capacity assessment demonstrated marked deficiencies in items for diagnosis, and in perioperative and vascular surgical care. Deficiencies were most often due to absence of equipment, lack of training and technology breakage. Risk factor reduction and management as well as optimization of current resources are paramount to avoid the large burden of PVD falling on healthcare systems in low- and middle-income countries. These countries are not well equipped to handle vascular surgical care, and rapid development of such capacity would be difficult and expensive. © 2015 BJS Society Ltd Published by John Wiley & Sons Ltd.

Vapor Phase Deposition Using Plasma Spray-PVD™

NASA Astrophysics Data System (ADS)

von Niessen, K.; Gindrat, M.; Refke, A.

2010-01-01

Plasma spray—physical vapor deposition (PS-PVD) is a low pressure plasma spray technology to deposit coatings out of the vapor phase. PS-PVD is a part of the family of new hybrid processes recently developed by Sulzer Metco AG (Switzerland) on the basis of the well-established low pressure plasma spraying (LPPS) technology. Included in this new process family are plasma spray—chemical vapor deposition (PS-CVD) and plasma spray—thin film (PS-TF) processes. In comparison to conventional vacuum plasma spraying and LPPS, these new processes use a high energy plasma gun operated at a work pressure below 2 mbar. This leads to unconventional plasma jet characteristics which can be used to obtain specific and unique coatings. An important new feature of PS-PVD is the possibility to deposit a coating not only by melting the feed stock material which builds up a layer from liquid splats, but also by vaporizing the injected material. Therefore, the PS-PVD process fills the gap between the conventional PVD technologies and standard thermal spray processes. The possibility to vaporize feedstock material and to produce layers out of the vapor phase results in new and unique coating microstructures. The properties of such coatings are superior to those of thermal spray and EB-PVD coatings. This paper reports on the progress made at Sulzer Metco to develop functional coatings build up from vapor phase of oxide ceramics and metals.

A review-application of physical vapor deposition (PVD) and related methods in the textile industry

NASA Astrophysics Data System (ADS)

Shahidi, Sheila; Moazzenchi, Bahareh; Ghoranneviss, Mahmood

2015-09-01

Physical vapor deposition (PVD) is a coating process in which thin films are deposited by the condensation of a vaporized form of the desired film material onto the substrate. The PVD process is carried out in a vacuum. PVD processes include different types, such as: cathode arc deposition, electron beam physical vapor deposition, evaporative deposition, sputtering, ion plating and enhanced sputtering. In the PVD method, the solid coating material is evaporated by heat or by bombardment with ions (sputtering). At the same time, a reactive gas is also introduced; it forms a compound with the metal vapor and is deposited on the substrate as a thin film with highly adherent coating. Such coatings are used in a wide range of applications such as aerospace, automotive, surgical, medical, dyes and molds for all manner of material processing, cutting tools, firearms, optics, thin films and textiles. The objective of this work is to give a comprehensive description and review of the science and technology related to physical vapor deposition with particular emphasis on their potential use in the textile industry. Physical vapor deposition has opened up new possibilities in the modification of textile materials and is an exciting prospect for usage in textile design and technical textiles. The basic principle of PVD is explained and the major applications, particularly sputter coatings in the modification and functionalization of textiles, are introduced in this research.

Transcutaneous electrical nerve stimulation as an additional treatment for women suffering from therapy-resistant provoked vestibulodynia: a feasibility study.

PubMed

Vallinga, Marleen S; Spoelstra, Symen K; Hemel, Inge L M; van de Wiel, Harry B M; Weijmar Schultz, Willibrord C M

2015-01-01

The current approach to women with provoked vestibulodynia (PVD) comprises a multidimensional, multidisciplinary therapeutic protocol. As PVD is considered to be a chronic pain disorder, transcutaneous electrical nerve stimulation (TENS) can be used as an additional therapy for women with otherwise therapy-resistant PVD. The aims of this study were to evaluate whether TENS has a beneficial effect on vulvar pain, sexual functioning, and sexually-related personal distress in women with therapy-resistant PVD and to assess the effect of TENS on the need for vestibulectomy. A longitudinal prospective follow-up study was performed on women with therapy-resistant PVD who received additional domiciliary TENS. Self-report questionnaires and visual analog scales (VASs) were completed at baseline (T1), post-TENS (T2), and follow-up (T3). Vulvar pain, sexual functioning, and sexually-related personal distress were the main outcome measures. Thirty-nine women with therapy-resistant PVD were included. Mean age was 27 ± 5.6 years (range: 19 to 41); mean duration between TENS and T3 follow-up was 10.1 ± 10.7 months (range: 2 to 32). Vulvar pain VAS scores directly post-TENS (median 3.4) and at follow-up (median 3.2) were significantly (P < 0.01) lower than at baseline (median 8.0). Post-TENS, sexual functioning scores on the Female Sexual Functioning Index questionnaire had improved significantly (P = 0.2); these scores remained stable at follow-up. Sexually-related personal distress scores had improved significantly post-TENS (P = 0.01). Only 4% of the women who received TENS needed to undergo vestibulectomy vs. 23% in our previous patient population. The addition of self-administered TENS to multidimensional treatment significantly reduced the level of vulvar pain and the need for vestibulectomy. The long-term effect was stable. These results not only support our hypothesis that TENS constitutes a feasible and beneficial addition to multidimensional treatment for therapy-resistant PVD, but also the notion that PVD can be considered as a chronic pain syndrome. © 2014 International Society for Sexual Medicine.

Physical vapor deposited thin films of lignins extracted from sugar cane bagasse: morphology, electrical properties, and sensing applications.

PubMed

Volpati, Diogo; Machado, Aislan D; Olivati, Clarissa A; Alves, Neri; Curvelo, Antonio A S; Pasquini, Daniel; Constantino, Carlos J L

2011-09-12

The concern related to the environmental degradation and to the exhaustion of natural resources has induced the research on biodegradable materials obtained from renewable sources, which involves fundamental properties and general application. In this context, we have fabricated thin films of lignins, which were extracted from sugar cane bagasse via modified organosolv process using ethanol as organic solvent. The films were made using the vacuum thermal evaporation technique (PVD, physical vapor deposition) grown up to 120 nm. The main objective was to explore basic properties such as electrical and surface morphology and the sensing performance of these lignins as transducers. The PVD film growth was monitored via ultraviolet-visible (UV-vis) absorption spectroscopy and quartz crystal microbalance, revealing a linear relationship between absorbance and film thickness. The 120 nm lignin PVD film morphology presented small aggregates spread all over the film surface on the nanometer scale (atomic force microscopy, AFM) and homogeneous on the micrometer scale (optical microscopy). The PVD films were deposited onto Au interdigitated electrode (IDE) for both electrical characterization and sensing experiments. In the case of electrical characterization, current versus voltage (I vs V) dc measurements were carried out for the Au IDE coated with 120 nm lignin PVD film, leading to a conductivity of 3.6 × 10(-10) S/m. Using impedance spectroscopy, also for the Au IDE coated with the 120 nm lignin PVD film, dielectric constant of 8.0, tan δ of 3.9 × 10(-3), and conductivity of 1.75 × 10(-9) S/m were calculated at 1 kHz. As a proof-of-principle, the application of these lignins as transducers in sensing devices was monitored by both impedance spectroscopy (capacitance vs frequency) and I versus time dc measurements toward aniline vapor (saturated atmosphere). The electrical responses showed that the sensing units are sensible to aniline vapor with the process being reversible. AFM images conducted directly onto the sensing units (Au IDE coated with 120 nm lignin PVD film) before and after the sensing experiments showed a decrease in the PVD film roughness from 5.8 to 3.2 nm after exposing to aniline.

Effects of exogenous pyoverdines on Fe availability and their impacts on Mn(II) oxidation by Pseudomonas putida GB-1

PubMed Central

Lee, Sung-Woo; Parker, Dorothy L.; Geszvain, Kati; Tebo, Bradley M.

2014-01-01

Pseudomonas putida GB-1 is a Mn(II)-oxidizing bacterium that produces pyoverdine-type siderophores (PVDs), which facilitate the uptake of Fe(III) but also influence MnO2 formation. Recently, a non-ribosomal peptide synthetase mutant that does not synthesize PVD was described. Here we identified a gene encoding the PVDGB-1 (PVD produced by strain GB-1) uptake receptor (PputGB1_4082) of strain GB-1 and confirmed its function by in-frame mutagenesis. Growth and other physiological responses of these two mutants and of wild type were compared during cultivation in the presence of three chemically distinct sets of PVDs (siderotypes n°1, n°2, and n°4) derived from various pseudomonads. Under iron-limiting conditions, Fe(III) complexes of various siderotype n°1 PVDs (including PVDGB-1) allowed growth of wild type and the synthetase mutant, but not the receptor mutant, confirming that iron uptake with any tested siderotype n°1 PVD depended on PputGB1_4082. Fe(III) complexes of a siderotype n°2 PVD were not utilized by any strain and strongly induced PVD synthesis. In contrast, Fe(III) complexes of siderotype n°4 PVDs promoted the growth of all three strains and did not induce PVD synthesis by the wild type, implying these complexes were utilized for iron uptake independent of PputGB1_4082. These differing properties of the three PVD types provided a way to differentiate between effects on MnO2 formation that resulted from iron limitation and others that required participation of the PVDGB-1 receptor. Specifically, MnO2 production was inhibited by siderotype n°1 but not n°4 PVDs indicating PVD synthesis or PputGB1_4082 involvement rather than iron-limitation caused the inhibition. In contrast, iron limitation was sufficient to explain the inhibition of Mn(II) oxidation by siderotype n°2 PVDs. Collectively, our results provide insight into how competition for iron via siderophores influences growth, iron nutrition and MnO2 formation in more complex environmental systems. PMID:25009534

Regional vascular density-visual field sensitivity relationship in glaucoma according to disease severity.

PubMed

Shin, Joong Won; Lee, Jiyun; Kwon, Junki; Choi, Jaewan; Kook, Michael S

2017-12-01

To study whether there are global and regional relationships between peripapillary vascular density (pVD) assessed by optical coherence tomography angiography (OCT-A) and visual field (VF) mean sensitivity at different glaucoma stages. Microvascular images and peripapillary retinal nerve fibre layer (pRNFL) thicknesses were obtained using a Cirrus OCT-A device in 91 glaucoma subjects. The pVD was measured at various spatial locations according to the Garway-Heath map, using a MATLAB software (The MathWorks, Natick, Massachusetts). VF mean sensitivity (VFMS) was recorded in the 1/L scale. Global and regional vasculature-function (pVD vs VFMS) relationships were assessed in separate patient groups at mild and moderate-to-advanced stages of glaucoma. The pVDs at superotemporal and inferotemporal regions were significantly associated with corresponding VFMS in mild glaucoma (p<0.05). In moderate-to-advanced glaucoma, there were significant associations between pVD and VFMS, regardless of location. The association between global pVD and VFMS was significantly stronger than that between global pRNFL thickness and VFMS in moderate-to-advanced stage glaucoma (p <0.05). Global and regional pVD measured by OCT-A was significantly associated with corresponding VFMS in moderate-to-advanced glaucoma. OCT-A may be useful in monitoring glaucoma at various stages. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Separate transcriptionally regulated pathways specify distinct classes of sister dendrites in a nociceptive neuron.

PubMed

O'Brien, Barbara M J; Palumbos, Sierra D; Novakovic, Michaela; Shang, Xueying; Sundararajan, Lakshmi; Miller, David M

2017-12-15

The dendritic processes of nociceptive neurons transduce external signals into neurochemical cues that alert the organism to potentially damaging stimuli. The receptive field for each sensory neuron is defined by its dendritic arbor, but the mechanisms that shape dendritic architecture are incompletely understood. Using the model nociceptor, the PVD neuron in C. elegans, we determined that two types of PVD lateral branches project along the dorsal/ventral axis to generate the PVD dendritic arbor: (1) Pioneer dendrites that adhere to the epidermis, and (2) Commissural dendrites that fasciculate with circumferential motor neuron processes. Previous reports have shown that the LIM homeodomain transcription factor MEC-3 is required for all higher order PVD branching and that one of its targets, the claudin-like membrane protein HPO-30, preferentially promotes outgrowth of pioneer branches. Here, we show that another MEC-3 target, the conserved TFIIA-like zinc finger transcription factor EGL-46, adopts the alternative role of specifying commissural dendrites. The known EGL-46 binding partner, the TEAD transcription factor EGL-44, is also required for PVD commissural branch outgrowth. Double mutants of hpo-30 and egl-44 show strong enhancement of the lateral branching defect with decreased numbers of both pioneer and commissural dendrites. Thus, HPO-30/Claudin and EGL-46/EGL-44 function downstream of MEC-3 and in parallel acting pathways to direct outgrowth of two distinct classes of PVD dendritic branches. Copyright © 2017 Elsevier Inc. All rights reserved.

Mismatch negativity as a potential neurobiological marker of early-stage Alzheimer disease and vascular dementia.

PubMed

Jiang, Shixiang; Yan, Chang; Qiao, Zhengxue; Yao, Haiqian; Jiang, Shiquan; Qiu, Xiaohui; Yang, Xiuxian; Fang, Deyu; Yang, Yanjie; Zhang, Limei; Wang, Lina; Zhang, Liming

2017-04-24

Alzheimer's disease (AD) and vascular dementia (VD) are serious, irreversible forms of cognitive impairment, which means that an early diagnosis is essential to slow down their progression. One potential neurophysiological biomarker of these diseases is the mismatch negativity (MMN) event-related potentials (ERP) component, which reflects an automatic detection mechanism at the pre-attentive stages of information processing. We evaluated the auditory MMN response in individuals from two patient groups: those in the prodromal stages of AD (P-AD) and those in the prodromal stages of VD (P-VD). Thirty patients (15 P-AD patients and 15 P-VD patients) and 30 age-matched controls were recruited to undergo electrophysiological recordings during the presentation of an auditory deviant-standard-reverse oddball paradigm that was used to elicit genuine MMN responses. We show that over the frontal-central area, the mean amplitude of the MMN was significantly reduced in both the P-AD (p=0.017) and P-VD groups (p=0.013) compared with controls. The MMN peak latency in P-VD patients was significantly shorter than in controls (p=0.027). No MMN response differences between the P-AD and P-VD were found in either the frontal-central or the temporal areas. These results indicate that P-AD and P-VD patients exhibit impaired pre-attentive information processing mechanisms as revealed by the frontal-central area MMN response, which is associated with sensory memory and cognitive deficits. Copyright © 2017 Elsevier B.V. All rights reserved.

Stability, frequency and multiplicity of transposon insertions in the pyoverdine region in the chromosomes of different fluorescent pseudomonads.

PubMed

Cornelis, P; Anjaiah, V; Koedam, N; Delfosse, P; Jacques, P; Thonart, P; Neirinckx, L

1992-07-01

Tn5 mutagenesis of different fluorescent pseudomonads was achieved by conjugational transfer of the suicide vector pSUP 10141. Pyoverdine negative (Pvd-) mutants were detected by the absence of fluorescence on King's B medium and by their inability to grow in the presence of the iron chelator EDDHA [ethylenediamine di(o-hydroxyphenylacetic acid)]. In P. fluorescens ATCC 17400 and three rhizosphere isolates (one P. putida and two P. fluorescens), the percentage of Pvd- mutants ranged between 0 and 0.54%. In a P. chlororaphis rhizosphere isolate, this percentage was higher (4%). In these mutants both of the Tn5 antibiotic resistances (Km and Tc) were stable and the transposon could be detected by hybridization. In Pvd- mutants of P. fluorescens ATCC 17400, the transposon was found to be inserted twice in the chromosome while single insertions were detected in the DNA of other, randomly tested mutants. In P. aeruginosa PAO1, where 13.1% of the mutants were Pvd-, both antibiotic resistances were rapidly lost and accordingly no transposon insertion could be detected by hybridization. However, the Pvd- phenotype was generally stable in these mutants. The plasmid pNK862 containing a mini-Tn10 transposon was introduced by electroporation into P. aeruginosa PAO1 and Kmr mutants were recovered, 89% of which were Pvd- and confirmed to be P. aeruginosa by PCR amplification of the P. aeruginosa lipoprotein gene. The mini-Tn10 insertions were also found to be unstable in PAO1.

Genetic and functional analysis of the bovine uterine microbiota. Part II: Purulent vaginal discharge versus healthy cows.

PubMed

Bicalho, M L S; Lima, S; Higgins, C H; Machado, V S; Lima, F S; Bicalho, R C

2017-05-01

The aim of this study was to characterize, using metagenomic shotgun DNA sequencing, the intrauterine microbial population and its predicted functional diversity within healthy cows and cows presenting purulent vaginal discharge (PVD). Twenty Holstein dairy cows from a single farm were enrolled in the study at 25 to 35 d postpartum. Purulent vaginal discharge was diagnosed by retrieving and scoring vaginal discharge using the Metricheck device (Simcro, Hamilton, New Zealand). Intrauterine samples for metagenomic analysis were collected by the cytobrush technique from 8 cows diagnosed with PVD and 12 healthy cows. Pair-end sequencing was performed using the Illumina MiSeq platform (Illumina Inc., San Diego, CA). Metagenomic sequences were analyzed using the MG-RAST server (metagenomic rapid annotations using subsystems technology; http://metagenomics.anl.gov/), and the STAMP software (http://kiwi.cs.dal.ca/Software/STAMP) was used to study statistically significant differential abundance of taxonomic and functional features between the 2 metagenomes. Additionally, the total number of bacterial 16S rDNA copies was estimated by real-time PCR. Taxonomic analysis revealed that Bacteroidetes was the most abundant phylum in the uterine microbiota from cows with PVD, and Fusobacteria was almost completely absent in the healthy uterine microbiota. Moreover, species belonging to the genus Trueperella were present only in the uterine microbiota of PVD cows. The increased abundance of Fusobacteria and the unique presence of Trueperella in the PVD cows highlight the important role of these bacteria in the pathogenesis of PVD. Genes encoding cytolethal distending toxin were exclusive to the microbiota of PVD cows. Similarly, genes associated with lipid A modification were present only in samples from PVD cows; such modification is associated with greater resistance to cationic antimicrobial peptides. Conversely, genes encoding bacteriocins and ribosomally antibacterial peptide were exclusively found in the healthy uterine microbiota and dominated by tolerance to colicin E2. No difference was observed in total bacterial load between the 2 microbiotas. This study provides deep insight into the uterine microbial community in health and disease. The observations that the healthy microbiota is tolerant to colicin E2, whereas the uterine microbiota of PVD cows produces cytolethal distending toxins and modifies its lipopolysaccharides suggest that species-intrinsic factors may be more relevant than bacterial abundance to the development of disease or maintenance of health in the dairy cow postpartum uterus. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

PVD TBC experience on GE aircraft engines

NASA Technical Reports Server (NTRS)

Maricocchi, Antonio; Bartz, Andi; Wortman, David

1995-01-01

The higher performance levels of modern gas turbine engines present significant challenges in the reliability of materials in the turbine. The increased engine temperatures required to achieve the higher performance levels reduce the strength of the materials used in the turbine sections of the engine. Various forms of thermal barrier coatings (TBC's) have been used for many years to increase the reliability of gas turbine engine components. Recent experience with the physical vapor deposition (PVD) process using ceramic material has demonstrated success in extending the service life of turbine blades and nozzles. Engine test results of turbine components with a 125 micron (0.005 in) PVD TBC have demonstrated component operating temperatures of 56-83 C (100-150 F) lower than non-PVD TBC components. Engine testing has also revealed the TBC is susceptible to high angle particle impact damage. Sand particles and other engine debris impact the TBC surface at the leading edge of airfoils and fracture the PVD columns. As the impacting continues, the TBC erodes away in local areas. Analysis of the eroded areas has shown a slight increase in temperature over a fully coated area, however a significant temperature reduction was realized over an airfoil without TBC.

Schottky Barrier Height Engineering for Electrical Contacts of Multilayered MoS2 Transistors with Reduction of Metal-Induced Gap States.

PubMed

Kim, Gwang-Sik; Kim, Seung-Hwan; Park, June; Han, Kyu Hyun; Kim, Jiyoung; Yu, Hyun-Yong

2018-06-06

The difficulty in Schottky barrier height (SBH) control arising from Fermi-level pinning (FLP) at electrical contacts is a bottleneck in designing high-performance nanoscale electronics and optoelectronics based on molybdenum disulfide (MoS 2 ). For electrical contacts of multilayered MoS 2 , the Fermi level on the metal side is strongly pinned near the conduction-band edge of MoS 2 , which makes most MoS 2 -channel field-effect transistors (MoS 2 FETs) exhibit n-type transfer characteristics regardless of their source/drain (S/D) contact metals. In this work, SBH engineering is conducted to control the SBH of electrical top contacts of multilayered MoS 2 by introducing a metal-interlayer-semiconductor (MIS) structure which induces the Fermi-level unpinning by a reduction of metal-induced gap states (MIGS). An ultrathin titanium dioxide (TiO 2 ) interlayer is inserted between the metal contact and the multilayered MoS 2 to alleviate FLP and tune the SBH at the S/D contacts of multilayered MoS 2 FETs. A significant alleviation of FLP is demonstrated as MIS structures with 1 nm thick TiO 2 interlayers are introduced into the S/D contacts. Consequently, the pinning factor ( S) increases from 0.02 for metal-semiconductor (MS) contacts to 0.24 for MIS contacts, and the controllable SBH range is widened from 37 meV (50-87 meV) to 344 meV (107-451 meV). Furthermore, the Fermi-level unpinning effect is reinforced as the interlayer becomes thicker. This work widens the scope for modifying electrical characteristics of contacts by providing a platform to control the SBH through a simple process as well as understanding of the FLP at the electrical top contacts of multilayered MoS 2 .

Influence of Hydrogen Bonding on the Kinetic Stability of Vapor Deposited Glasses of Triazine Derivatives

DOE Data Explorer

Laventure, Audrey [Departement de chimie, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7, Canada] (ORCID:0000000208670231); Gujral, Ankit [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States] (ORCID:0000000250652694); Lebel, Olivier [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario K7K 7B4] (ORCID:0000000217376843); Ediger, Mark [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States] (ORCID:0000000347158473); Pellerin, Christian [Departement de chimie, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7, Canada] (ORCID:0000000161441318)

2017-02-01

It has recently been established that physical vapor deposition (PVD) can produce organic glasses with enhanced kinetic stability, high density, and anisotropic packing, with the substrate temperature during deposition (Tsubstrate) as the key control parameter. The influence of hydrogen bonding on the formation of PVD glasses has not been fully explored. Herein, we use a high-throughput preparation method to vapor-deposit three triazine derivatives over a wide range of Tsubstrate, from 0.69 to 1.08Tg, where Tg is the glass transition temperature. These model systems are structural analogues containing a functional group with different H-bonding capability at the 2-position of a triazine ring: (1) 2-methylamino-4,6-bis(3,5-dimethyl-phenylamino)-1,3,5-triazine (NHMe) (H-bond donor), (2) 2-methoxy-4,6-bis(3,5-dimethyl-phenylamino)-1,3,5-triazine (OMe) (H-bond acceptor), and (3) 2-ethyl-4,6-bis(3,5-dimethyl-phenylamino)-1,3,5-triazine (Et) (none). Using spectroscopic ellipsometry, we find that the Et and OMe compounds form PVD glasses with relatively high kinetic stability, with the transformation time (scaled by the α-relaxation time) on the order of 103, comparable to other highly stable glasses formed by PVD. In contrast, PVD glasses of NHMe are only slightly more stable than the corresponding liquid-cooled glass. Using IR spectroscopy, we find that both the supercooled liquid and the PVD glasses of the NHMe derivative show a higher average number of bonded NH per molecule than that in the other two compounds. These results suggest that H-bonds hinder the formation of stable glasses, perhaps by limiting the surface mobility. Interestingly, despite this difference in kinetic stability, all three compounds show properties typically observed in highly stable glasses prepared by PVD, including a higher density and anisotropic molecular packing (as characterized by IR and wide-angle X-ray scattering).

Improved performance of GaN based light emitting diodes with ex-situ sputtered AlN nucleation layers

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

Chen, Shuo-Wei; Epistar Corporation, Hsinchu 300, Taiwan; Li, Heng

The crystal quality, electrical and optical properties of GaN based light emitting diodes (LEDs) with ex-situ sputtered physical vapor deposition (PVD) aluminum nitride (AlN) nucleation layers were investigated. It was found that the crystal quality in terms of defect density and x-ray diffraction linewidth was greatly improved in comparison to LEDs with in-situ low temperature GaN nucleation layer. The light output power was 3.7% increased and the reverse bias voltage of leakage current was twice on LEDs with ex-situ PVD AlN nucleation layers. However, larger compressive strain was discovered in LEDs with ex-situ PVD AlN nucleation layers. The study showsmore » the potential and constrain in applying ex-situ PVD AlN nucleation layers to fabricate high quality GaN crystals in various optoelectronics.« less

Identification of a new Apscaviroid from Japanese persimmon.

PubMed

Nakaune, Ryoji; Nakano, Masaaki

2008-01-01

Three viroid-like sequences were detected from Japanese persimmon (Diospyrus kaki Thunb.) by RT-PCR using primers specific for members of the genus Apscaviroid. Based on the sequences, we determined the complete genomic sequences. Two had 92.1-94.3% sequence identity with citrus viroid OS (CVd-OS) and 91.4-96.3% identity with apple fruit crinkle viroid (AFCVd), respectively. Another one, tentatively named persimmon viroid (PVd), had 396 nucleotides and less than 70% sequence identity with known viroids. The secondary structure of PVd is proposed to be rod-like with extensive base pairing and contains the terminal conserved region and the central conserved region characteristic of the genus Apscaviroid. Moreover, we confirmed that the viroids, including PVd, are graft transmissible from persimmon to persimmon and that persimmon is a natural host of these viroids. According to its molecular and biological properties, PVd should be considered a member of a new species in the genus Apscaviroid.

The role of energetic ions from plasma in the creation of nanostructured materials and stable polymer surface treatments

NASA Astrophysics Data System (ADS)

Bilek, M. M. M.; Newton-McGee, K.; McKenzie, D. R.; McCulloch, D. G.

2006-01-01

Plasma processes for the synthesis of new materials as thin films have enabled the production of a wide variety of new materials. These include meta-stable phases, which are not readily found in nature, and more recently, materials with structure on the nanoscale. Study of plasma synthesis processes at the fundamental level has revealed that ion energy, depositing flux and growth surface temperature are the critical parameters affecting the microstructure and the properties of the thin film materials formed. In this paper, we focus on the role of ion flux and impact energy in the creation of thin films with nanoscale structure in the form of multilayers. We describe three synthesis strategies, based on the extraction of ions from plasma sources and involving modulation of ion flux and ion energy. The microstructure, intrinsic stress and physical properties of the multilayered samples synthesized are studied and related back to the conditions at the growth surface during deposition. When energetic ions of a non-condensing species are used, it is possible to place active groups on the surfaces of materials such as polymers. These active groups can then be used as bonding sites in subsequent chemical attachment of proteins or other macromolecules. If the energy of the non-condensing ions is increased to a few keV then modified layers buried under the surface can be produced. Here we describe a method by which the aging effect, which is often observed in plasma surface modifications on polymers, can be reduced and even eliminated using high energy ion bombardment.

Provoked vestibulodynia: current perspectives

PubMed Central

Henzell, Helen; Berzins, Karen; Langford, Jennifer P

2017-01-01

Provoked vestibulodynia (PVD) refers to vulvar pain of at least 3 months duration, localized to the vestibule, provoked by touch and sexual activity and occurring in the absence of a clear identifiable cause. The clinical spectrum ranges from mild with distressing discomfort through to severe and disabling pain. Current understanding is that PVD is one of many chronic pain conditions characterized by sensitization of peripheral and central nociceptive pathways, with pain arising due to dysfunctional neuronal activity in the absence of painful stimuli. Pathophysiology is not well understood but is likely a complex interplay of environmental, genetic, psychological and immune factors. Care is multidisciplinary and follows general principles of chronic pain management with the addition of specific therapy tailored to address pelvic floor overactivity, and sexual and relationship difficulties. More recently, the therapeutic use of placebo is gaining traction in chronic pain research and is a very promising adjunctive therapy. The majority of women with PVD are managed outside of tertiary clinic settings, and care depends on availability and affordability of specialized services; however, much can be done by the primary health provider. PVD is common, and highly treatable, especially with early intervention, but unfortunately, many clinicians are unaware of this condition, and the biggest hurdle for women accessing treatment is obtaining a diagnosis. With treatment, most women can expect significant improvement, often with fairly simple interventions, although some women will benefit from referral to specialized centers. The aims of this article are twofold: firstly, to summarize current literature concerning PVD pathophysiology and management; secondly, to provide a framework for clinicians unfamiliar with vulvar medicine to understand and manage PVD. PMID:28979166

New pulmonary vein Doppler echocardiographic index predicts significant interatrial shunting in secundum atrial septal defect.

PubMed

Lam, Yat-Yin; Fang, Fang; Yip, Gabriel Wai-Kwok; Li, Zhi-An; Yang, Ya; Yu, Cheuk-Man

2012-09-20

The relation between pulmonary venous flow (PVF) pattern and degree of left-to-right interatrial shunting (IAS) in patients with secundum atrial septal defect (ASD) is unknown. Fifty consecutive ASD patients (14 males, 36 ± 17 years) received transthoracic echocardiography (TTE) before and 1 day after transcatheter closure and their results were compared to 40 controls. The ratio of pulmonary-to-systemic flows (Qp/Qs) was assessed by TTE and invasive oximetry. Pre-closure PV systolic (PVs), diastolic (PVd) velocities and velocity-time integral (PV-VTI) increased, time from onset of ECG Q-wave to the peak PV diastolic wave (Q-PVd) shortened and atrial reversal (PVar) velocity significantly decreased as compared to normals. These findings normalized after closure. Patients with large IAS (defined as invasive Qp/Qs ≥ 2) had higher PVs, PVd and PV-VTI, shorter Q-PVd but lower PVar (all p<0.01) than those with small IAS. Invasive Qp/Qs ratios correlated with PVs, PVd, PV-VTI, Q-PVd and TTE-derived Qp/Qs ratios, ASD sizes and RV end-diastolic dimensions (all p<0.05). PV-VTI (β=0.49) and ASD size (β=0.48) remained independent predictors of large IAS after multivariate analysis. The corresponding sensitivity, specificity and AUC were 89%, 82% and 0.90 respectively for a PV-VTI of 30 cm (p<0.001). ASD patients with significant IAS have distinguishable PVF features. Doppler evaluation of PV-VTI is a novel additional tool for assessing the magnitude of shunting in these patients non-invasively. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Biosynthesis of Novel Pyoverdines by Domain Substitution in a Nonribosomal Peptide Synthetase of Pseudomonas aeruginosa

PubMed Central

Calcott, Mark J.; Owen, Jeremy G.; Lamont, Iain L.

2014-01-01

Pyoverdine is a fluorescent nonribosomal peptide siderophore made by fluorescent pseudomonads. The Pseudomonas aeruginosa nonribosomal peptide synthetase (NRPS) PvdD contains two modules that each incorporate an l-threonine residue at the C-terminal end of pyoverdine. In an attempt to generate modified pyoverdine peptides, we substituted alternative-substrate-specifying adenylation (A) and peptide bond-catalyzing condensation (C) domains into the second module of PvdD. When just the A domain was substituted, the resulting strains produced only wild-type pyoverdine—at high levels if the introduced A domain specified threonine or at trace levels otherwise. The high levels of pyoverdine synthesis observed whenever the introduced A domain specified threonine indicated that these nonnative A domains were able to communicate effectively with the PvdD C domain. Moreover, the unexpected observation that non-threonine-specifying A domains nevertheless incorporated threonine into pyoverdine suggests that the native PvdD C domain exhibited stronger selectivity than these A domains for the incorporated amino acid substrate (i.e., misactivation of a threonine residue by the introduced A domains was more frequent than misincorporation of a nonthreonine residue by the PvdD C domain). In contrast, substitution of both the C and A domains of PvdD generated high yields of rationally modified pyoverdines in two instances, these pyoverdines having either a lysine or a serine residue in place of the terminal threonine. However, C-A domain substitution more commonly yielded a truncated peptide product, likely due to stalling of synthesis on a nonfunctional recombinant NRPS template. PMID:25015884

Direct writing of room temperature and zero field skyrmion lattices by a scanning local magnetic field

NASA Astrophysics Data System (ADS)

Zhang, Senfu; Zhang, Junwei; Zhang, Qiang; Barton, Craig; Neu, Volker; Zhao, Yuelei; Hou, Zhipeng; Wen, Yan; Gong, Chen; Kazakova, Olga; Wang, Wenhong; Peng, Yong; Garanin, Dmitry A.; Chudnovsky, Eugene M.; Zhang, Xixiang

2018-03-01

Magnetic skyrmions are topologically protected nanoscale spin textures exhibiting fascinating physical behaviors. Recent observations of room temperature skyrmions in sputtered multilayer films are an important step towards their use in ultra-low power devices. Such practical applications prefer skyrmions to be stable at zero magnetic fields and room temperature. Here, we report the creation of skyrmion lattices in Pt/Co/Ta multilayers by a scanning local field using magnetic force microscopy tips. We also show that those newly created skyrmion lattices are stable at both room temperature and zero fields. Lorentz transmission electron microscopy measurements reveal that the skyrmions in our films are of Néel-type. To gain a deeper understanding of the mechanism behind the creation of a skyrmion lattice by the scanning of local fields, we perform micromagnetic simulations and find the experimental results to be in agreement with our simulation data. This study opens another avenue for the creation of skyrmion lattices in thin films.

Quantifying quality in DNA self-assembly

PubMed Central

Wagenbauer, Klaus F.; Wachauf, Christian H.; Dietz, Hendrik

2014-01-01

Molecular self-assembly with DNA is an attractive route for building nanoscale devices. The development of sophisticated and precise objects with this technique requires detailed experimental feedback on the structure and composition of assembled objects. Here we report a sensitive assay for the quality of assembly. The method relies on measuring the content of unpaired DNA bases in self-assembled DNA objects using a fluorescent de-Bruijn probe for three-base ‘codons’, which enables a comparison with the designed content of unpaired DNA. We use the assay to measure the quality of assembly of several multilayer DNA origami objects and illustrate the use of the assay for the rational refinement of assembly protocols. Our data suggests that large and complex objects like multilayer DNA origami can be made with high strand integration quality up to 99%. Beyond DNA nanotechnology, we speculate that the ability to discriminate unpaired from paired nucleic acids in the same macromolecule may also be useful for analysing cellular nucleic acids. PMID:24751596

Freely suspended nanocomposite membranes as highly sensitive sensors

NASA Astrophysics Data System (ADS)

Jiang, Chaoyang; Markutsya, Sergiy; Pikus, Yuri; Tsukruk, Vladimir V.

2004-10-01

Highly sensitive sensor arrays are in high demand for prospective applications in remote sensing and imaging. Measuring microscopic deflections of compliant micromembranes and cantilevers is developing into one of the most versatile approaches for thermal, acoustic and chemical sensing. Here, we report on an innovative fabrication of compliant nanocomposite membranes with nanoscale thickness showing extraordinary sensitivity and dynamic range, which makes them candidates for a new generation of membrane-based sensor arrays. These nanomembranes with a thickness of 25-70 nm, which can be freely suspended over large (hundred micrometres) openings are fabricated with molecular precision by time-efficient, spin-assisted layer-by-layer assembly. They are designed as multilayered molecular composites made of a combination of polymeric monolayers and a metal nanoparticle intralayer. We demonstrate that these nanocomposite membranes possess unparalleled sensitivity and a unique autorecovering ability. The membrane nanostructure that is responsible for these outstanding properties combines multilayered polymer/nanoparticle organization, high polymer-chain orientation, and a pre-stretched state.

Nanoscale calibration of n-type ZnO staircase structures by scanning capacitance microscopy

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

Wang, L., E-mail: lin.wang@insa-lyon.fr; Laurent, J.; Brémond, G.

2015-11-09

Cross-sectional scanning capacitance microscopy (SCM) was performed on n-type ZnO multi-layer structures homoepitaxially grown by molecular beam epitaxy method. Highly contrasted SCM signals were obtained between the ZnO layers with different Ga densities. Through comparison with dopant depth profiles from secondary ion mass spectroscopy measurement, it is demonstrated that SCM is able to distinguish carrier concentrations at all levels of the samples (from 2 × 10{sup 17 }cm{sup −3} to 3 × 10{sup 20 }cm{sup −3}). The good agreement of the results from the two techniques indicates that SCM can be a useful tool for two dimensional carrier profiling at nanoscale for ZnO nanostructure development. Asmore » an example, residual carrier concentration inside the non-intentionally doped buffer layer was estimated to be around 2 × 10{sup 16 }cm{sup −3} through calibration analysis.« less

Switchable friction enabled by nanoscale self-assembly on graphene

DOE PAGES

Gallagher, Patrick; Lee, Menyoung; Amet, Francois; ...

2016-02-23

Graphene monolayers are known to display domains of anisotropic friction with twofold symmetry and anisotropy exceeding 200%. This anisotropy has been thought to originate from periodic nanoscale ripples in the graphene sheet, which enhance puckering around a sliding asperity to a degree determined by the sliding direction. Here we demonstrate that these frictional domains derive not from structural features in the graphene but from self-assembly of environmental adsorbates into a highly regular superlattice of stripes with period 4–6 nm. The stripes and resulting frictional domains appear on monolayer and multilayer graphene on a variety of substrates, as well as onmore » exfoliated flakes of hexagonal boron nitride. We show that the stripe-superlattices can be reproducibly and reversibly manipulated with submicrometre precision using a scanning probe microscope, allowing us to create arbitrary arrangements of frictional domains within a single flake. In conclusion, our results suggest a revised understanding of the anisotropic friction observed on graphene and bulk graphite in terms of adsorbates.« less

Examination of Hybrid Metal Coatings for Mitigation of Fission Product Release and Corrosion Protection of LWR SiC/SiC

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

Ang, Caen K.; Burns, Joseph R.; Terrani, Kurt A.

2016-09-01

There is a need to increase the safety margins of current and future light water reactors (LWRs) due to the unfortunate events at Fukushima Daiichi Nuclear Plant. Safety is crucial to restore public confidence in nuclear energy, acknowledged as an economical, high-­density energy solution to climate change. The development of accident-­tolerant fuel (ATF) concepts is crucial to this endeavor. The objective of ATF is to delay the consequences of accident progression, being inset in high temperature steam and maintaining high thermomechanical strength for radionuclide retention. The use of advanced SiCf-­SiC composite as a substitute for zircaloy-­based cladding is being considered.more » However, at normal operations, SiC is vulnerable to the reactor coolant and may corrode at an unacceptable rate. As a ceramic-­matrix composite material, it is likely to undergo microcracking operation, which may compromise the ability to contain gaseous fission products. A proposed solution to both issues is the application of mitigation coatings for use in normal operations. At Oak Ridge National Laboratory (ORNL), three coating technologies have been investigated with industry collaborators and vendors. These are electrochemical deposition, cathodic arc physical vapor deposition (PVD hereafter) and vacuum plasma spray (VPS). The objective of this document is to summarize these processing technologies, the resultant as-­processed microstructures and properties of the coatings. In all processes, substrate constraint resulted in substantial tensile stresses within the coating layer. Each technology must mitigate this tensile stress. Electrochemical coatings use chromium as the coolant facing material, and are deposited on a nickel or carbon “bond coat”. This is economical but suffers microcracking in the chromium layer. PVD-­based coatings use chromium and titanium in both metallic form and nitrides, and can be deposited defense-­in-­depth as multilayers. This vapor method eliminated tensile stress during processing and coatings were up to ~30 μm thick without microcracking. VPS produced coatings based on Zircaloy-2, which has a proven reactor-­compatibility. The tensile stresses appearred to be partially mitigated by annealing. Analysis showed that VPS coatings required further optimizations to prevent adverse reactions with the substrate and need a minimum thickness of ~50 μm. In addition, development of coatings are constrained by neutronic depletion analysis, which clearly indicated enrichment as an issue if the coating is too thick. Based on the present work, the cathodic arc PVD technology was considered ready for the extensive testing and evaluation on cladding materials due to their ability to mitigate the excessive tensile stresses and the reasonable coating quality achieved. The VPS Zircaloy-­2 coating technology required additional development toward mitigation of issues related to the substrate reaction and porosity. In the future, PVD and VPS will have be scaled upon successful development and demonstration. Electrochemical coatings, which are proven scalability, currently require development to mitigate issues related to the tensile stress after deposition.« less

Reducing virulence of the human pathogen Burkholderia by altering the substrate specificity of the quorum-quenching acylase PvdQ

PubMed Central

Koch, Gudrun; Nadal-Jimenez, Pol; Reis, Carlos R.; Muntendam, Remco; Bokhove, Marcel; Melillo, Elena; Dijkstra, Bauke W.; Cool, Robbert H.; Quax, Wim J.

2014-01-01

The use of enzymes to interfere with quorum sensing represents an attractive strategy to fight bacterial infections. We used PvdQ, an effective quorum-quenching enzyme from Pseudomonas aeruginosa, as a template to generate an acylase able to effectively hydrolyze C8-HSL, the major communication molecule produced by the Burkholderia species. We discovered that the combination of two single mutations leading to variant PvdQLα146W,Fβ24Y conferred high activity toward C8-HSL. Exogenous addition of PvdQLα146W,Fβ24Y dramatically decreased the amount of C8-HSL present in Burkholderia cenocepacia cultures and inhibited a quorum sensing-associated phenotype. The efficacy of this PvdQ variant to combat infections in vivo was further confirmed by its ability to rescue Galleria mellonella larvae upon infection, demonstrating its potential as an effective agent toward Burkholderia infections. Kinetic analysis of the enzymatic activities toward 3-oxo-C12-L-HSL and C8-L-HSL corroborated a substrate switch. This work demonstrates the effectiveness of quorum-quenching acylases as potential novel antimicrobial drugs. In addition, we demonstrate that their substrate range can be easily switched, thereby paving the way to selectively target only specific bacterial species inside a complex microbial community. PMID:24474783

P-channel transparent thin-film transistor using physical-vapor-deposited NiO layer

NASA Astrophysics Data System (ADS)

Lin, Chiung-Wei; Chung, Wei-Chieh; Zhang, Zhao-De; Hsu, Ming-Chih

2018-01-01

The effect of oxygen (O) content on the electrical properties of physical-vapor-deposited nickel oxide (PVD-NiO) was studied. When the NiO target was sputtered, introducing O2 can lead to the formation of Ni3+ ions in the deposited film. These Ni3+ ions can act as acceptors. However, there were too many Ni3+ ions that were obtained following the introduction of O atoms. It resulted in intensive p-type conduction and made the O2-introduced PVD-NiO behave as a conductor. Thus, it was possible to reduce the O content of PVD-NiO to obtain a p-type semiconductor. In this study, a transparent PVD-NiO film with a carrier concentration of 1.62 × 1017 cm-3 and a resistivity of 3.74 Ω cm was sputter-deposited within pure argon plasma. The thin-film transistor (TFT) employing this proposed PVD-NiO can result in good current switching, and even operated at very low drain-source voltage. The ON/OFF current ratio, field-effect carrier mobility, and threshold voltage of the proposed NiO TFT were 3.61 × 104, 1.09 cm2 V-1 s-1 and -3.31 V, respectively.

Nano-scale observations of interface between lichen and basaltic rock: Pseudomorphic growth of amorphous silica on augite

NASA Astrophysics Data System (ADS)

Tamura, T.; Kyono, A.; Kebukawa, Y.; Takagi, S.

2017-12-01

Recently, lichens as the earliest colonizers of terrestrial habitats are recognized to accelerate the mineral degradation at the interface between lichens and surface rocks. Much interest has been therefore devoted in recent years to the weathering induced by the lichen colonization. Here, we report nano-scale observations of the interface between lichens and basaltic rock by TEM and STXM techniques. Some samples of basaltic rocks totally covered by lichens were collected from the 1986 lava flows on the northwest part of Izu-Oshima volcano, Japan. To prepare specimens for the nano-scale observation, we utilized the focused ion beam (FIB) system. The microstructure and local chemistry of the specimens were thoroughly investigated by TEM equipped with energy-dispersive X-ray spectroscopy (EDX). Chemical components and chemical heterogeneity at the interface were observed by scanning transmission X-ray microscopy (STXM) at Advanced Light Source branch line 5.3.2.2. The collected rocks were classified into the augite-pigeonite-bronzite basalt including 6 to 8% plagioclase phenocrysts. The lichens adhering to the rocks were mainly Stereocaulon vesuvianum, fruticose lichen, which are widespread over the study area. The metabolites of the Stereocaulon vesuvianum exhibited a mean pH of 4.5 and dominance by acids. The STEM-EDX observations revealed that the interface between augite and the lichen was completely covered with amorphous silica multilayer with a thickness of less than 1 µm. Ca L-edge XANES spectra of the augite showed that the energy profile of the absorption edge at 349 eV was varied with the depth from the surface, indicating that the M2 site coordination accommodating Ca2+ undergoes significant change in shape as a function of distance from the surface. This behavior results from the fact that the M2 site is more distorted and more flexible in the C2/c clinopyroxene phase. Taking into consideration that the S. vesuvianum can produce acidic organic compounds during metabolism, the amorphous silica multilayers observed at the interface were produced by mineral dissolution induced by the lichen, and formed as a pseudomorphic replacement of augite by amorphous silica.

Synthesis and Characterization of 2-D Materials

NASA Astrophysics Data System (ADS)

Pazos, S.; Sahoo, P.; Afaneh, T.; Rodriguez Gutierrez, H.

Atomically thin transition-metal dichacogenides (TMD), graphene, and boron nitride (BN) are two-dimensional materials where the charge carriers (electrons and holes) are confined to move in a plane. They exhibit distinctive optoelectronic properties compared to their bulk layered counterparts. When combined into heterostructures, these materials open more possibilities in terms of new properties and device functionality. In this work, WSe2 and graphene were grown using Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD) techniques. The quality and morphology of each material was checked using Raman, Photoluminescence Spectroscopy, and Scanning Electron Microscopy. Graphene had been successfully grown homogenously, characterized, and transferred from copper to silicon dioxide substrates; these films will be used in future studies to build 2-D devices. Different morphologies of WSe2 2-D islands were successfully grown on SiO2 substrates. Depending on the synthesis conditions, the material on each sample had single layer, double layer, and multi-layer areas. A variety of 2-D morphologies were also observed in the 2-D islands. This project is supported by the NSF REU Grant #1560090 and NSF Grant #DMR-1557434.

Effect of Pseudomonas fluorescens and pyoverdine on the phytoextraction of cesium by red clover in soil pots and hydroponics.

PubMed

Hazotte, Alice; Péron, Olivier; Gaudin, Pierre; Abdelouas, Abdesselam; Lebeau, Thierry

2018-05-12

With the aim of improving the phytoextraction rate of cesium (Cs), the effect of Pseudomonas fluorescens ATCC 17400 and its siderophore pyoverdine (PVD) on the uptake of Cs by red clover was studied in soil pots. This work also provides a mechanistic understanding of the Cs-bacteria (or PVD)-illite-plant interactions by using a simplified experimental design, i.e., hydroponics with either Cs in solution or Cs-spiked illite in suspension. For soil spiked with 11.2 mmol kg -1 (1480 mg kg -1 ) of Cs, 0.43% of total Cs was taken up by red clover in 12 days (119 μmol g -1 (16 mg g -1 ) of Cs dry matter in roots and 40 μmol g -1 (5 mg g -1 ) in shoots). In hydroponics with Cs in solution (0.1 mmol L -1 or 13 mg L -1 ), 75% of Cs was taken up vs. only 0.86% with Cs-spiked illite suspension. P. fluorescens and PVD did not increase Cs concentrations in aboveground parts and roots of red clover and even decreased them. The damaging effect of PVD on red clover growth was demonstrated with the biomass yielding 66% of the control in soil pots (and 100% mortality after 12 days of exposition) and only 56% in hydroponics (78% with illite in suspension). Nonetheless, PVD and, to a lesser extent, P. fluorescens increased the translocation factor up to a factor of 2.8. This study clearly showed a direct damaging effect of PVD and to a lower extent the retention of Cs by biofilm covering both the roots and illite, both resulting in the lower phytoextraction efficiency.

Type 2 pyoverdine from Pseudomonas aeruginosa strain BUP2 as turn-off biosensor for the rapid detection of iron and copper ions in contaminated water.

PubMed

Unni, Kizhakkepowathial Nair; Priji, Prakasan; Sajith, Sreedharan; Faisal, Panichikkal Abdul; Shainy, Karippayi Mattil; Joseph, Abraham; Babu, Moolath Girish; Benjamin, Sailas

2016-09-23

Employing fluorescent quenching mechanism, type 2 pyoverdine (PVD) purified from Pseudomonas aeruginosa strain BUP2 (new strain isolated from the rumen of Malabari goat) was used as a simple, convenient and inexpensive tool for the rapid detection of Fe and Cu ions in contaminated drinking water samples. The fluorescence emitted at λ 460 by PVD (in sterile water), mounted on a glass slide was efficiently quenched by the ions of heavy metals like Fe and Cu. The fluorescence quenching effect of PVD was monitored using UV trans-illuminator, and subsequently quantified and confirmed by spectrofluorimetry. Upon exposure for about 50 sec at 25 °C, this quenching efficiency could directly be assessed by naked eye with the aid of a UV trans-illuminator. The linear range of detection for Fe was 1 to 60 µM, while that of Cu was 1 to 20 µM. The limits of detection at µM concentration for Fe 3+ , Fe 2+ and Cu 2+ were 0.23, 0.24 and 0.38, respectively. The quenching of fluorescence was more pronounced in Fe-PVD system than Cu-PVD, and this observation was in corroboration with the Pearson acid base concept; being a hard acid, Fe 3+ effectively bound with the O-ligands and this ability was less in Cu 2+ , a border line acid. Briefly, this study proposed the use of type 2 PVD as a turn-off biosensor for the rapid screening of heavy metals like Fe and Cu in drinking water, at ppm levels only with the aid of UV trans-illuminator at 25 °C in 50 sec.

Pulse oximetry in the evaluation of peripheral vascular disease.

PubMed

Jawahar, D; Rachamalla, H R; Rafalowski, A; Ilkhani, R; Bharathan, T; Anandarao, N

1997-08-01

The role of pulse oximetry in the evaluation of peripheral vascular disease (PVD) was investigated. In addition, the value of elevating the limb to improve the sensitivity of detection of PVD by the pulse oximeter was also determined. Pulse oximetry reading in the toes were obtained in 40 young, healthy volunteers and in 40 randomly selected patients referred to the vascular investigation laboratory over a period of two months. All 40 healthy volunteers had normal pulse oximetry readings. Normal pulse oximetry reading in the toes was defined as > 95% O2 Sat and +/-2 of finger pulse oximetry reading. In all 40 patients, pulse oximetry readings were either normal or not detected at all. Since there was no gradation in decrease in the pulse oximetry reading with severity of disease or with elevation of the patient's lower extremity, an absent or no reading was considered as an abnormal result from the test. The frequency of abnormal pulse oximetry readings increased significantly in groups with abnormal ankle-brachial pressure index (ABPI) and also varied significantly with elevation of the patients' lower limbs. In patients with no PVD detected by Doppler (ABPI > 0.9), pulse oximetry readings were normal in all. However, in patients with moderate PVD (ABPI, 0.5-0.9), 84% of the patients' lower limbs had normal pulse oximetry readings and 16% had an abnormal reading at baseline level (flat). An additional 12% of the lower limbs in this group had an abnormal reading on elevation of the limb to 12 inches. In patients with severe PVD (ABPI < 0.5), 54% of the patients' lower limbs had an abnormal reading at baseline and an additional 23% had an abnormal reading at elevation of the limb to 12 inches. In conclusion, pulse oximetry was not a sensitive test for detecting early PVD.

Differences in Pelvic Morphology Between Women With and Without Provoked Vestibulodynia.

PubMed

McLean, Linda; Thibault-Gagnon, Stephanie; Brooks, Kaylee; Goldfinger, Corrie; Pukall, Caroline; Chamberlain, Susan

2016-06-01

Pelvic morphology has been suggested to reflect increased tone and reduced strength of the pelvic floor muscles (PFMs) in women with provoked vestibulodynia (PVD) compared to healthy controls. We aimed to determine whether there are differences in pelvic morphology in the resting state, on maximum voluntary contraction (MVC), or on maximum effort Valsalva maneuver (MVM) between women with and without PVD. While imaged using ultrasound, 38 women with PVD and 39 controls relaxed their PFMs, performed 3 MVCs and performed 3 MVMs. Levator plate length (LPL), levator plate angle (LPA), and anorectal angle (ARA) were determined at rest, at MVC and at MVM. The displacement of the bladder neck (BN) on MVC and on MVM was also determined. Two-way ANCOVAs were used to evaluate the main effects of group and task, the interaction between group and task, and the effect of resting morphology on LPL, LPA, and ARA. A 2-way repeated-measures ANOVA was used to determine whether the groups differed in terms of BN displacement during the tasks. Women with PVD had smaller LPLs and LPAs than controls across all tasks. The significant group differences in LPL and LPA at MVC and MVM were no longer significant once the resting values were included as covariates in the models. Bladder neck displacement differed between the groups at MVM but not at MVC. Women with PVD display shorter LPL sand smaller LPAs than controls but their behavior does not differ when MVC and MVMs are performed. Our results do not support the hypothesis that women with PVD demonstrate abnormalities in PFM contractility on MVC or compliance on MVM. Copyright © 2016. Published by Elsevier Inc.

Investigating the Mobility of Trilayer Graphene Nanoribbon in Nanoscale FETs

NASA Astrophysics Data System (ADS)

Rahmani, Meisam; Ghafoori Fard, Hassan; Ahmadi, Mohammad Taghi; Rahbarpour, Saeideh; Habibiyan, Hamidreza; Varmazyari, Vali; Rahmani, Komeil

2017-10-01

The aim of the present paper is to investigate the scaling behaviors of charge carrier mobility as one of the most remarkable characteristics for modeling of nanoscale field-effect transistors (FETs). Many research groups in academia and industry are contributing to the model development and experimental identification of multi-layer graphene FET-based devices. The approach in the present work is to provide an analytical model for carrier mobility of tri-layer graphene nanoribbon (TGN) FET. In order to do so, one starts by identifying the analytical modeling of TGN carrier velocity and ballistic conductance. At the end, a model of charge carrier mobility with numerical solution is analytically derived for TGN FET, in which the carrier concentration, temperature and channel length characteristics dependence are highlighted. Moreover, variation of band gap and gate voltage during the proposed device operation and its effect on carrier mobility is investigated. To evaluate the nanoscale FET performance, the carrier mobility model is also adopted to obtain the I-V characteristics of the device. In order to verify the accuracy of the proposed analytical model for TGN mobility, it is compared to the existing experimental data, and a satisfactory agreement is reported for analogous ambient conditions. Moreover, the proposed model is compared with the published data of single-layer graphene and bi-layer graphene, in which the obtained results demonstrate significant insights into the importance of charge carrier mobility impact in high-performance TGN FET. The work presented here is one step towards an applicable model for real-world nanoscale FETs.

Development of CVD-W coatings on CuCrZr and graphite substrates with a PVD intermediate layer

NASA Astrophysics Data System (ADS)

Song, Jiupeng; Lian, Youyun; Lv, Yanwei; Liu, Junyong; Yu, Yang; Liu, Xiang; Yan, Binyou; Chen, Zhigang; Zhuang, Zhigang; Zhao, Ximeng; Qi, Yang

2014-12-01

In order to apply tungsten (W) coatings by chemical vapor deposition (CVD) for repairing or updating the plasma facing components (PFCs) of the first wall and divertor in existing or future tokomaks, where CuCrZr or graphite is the substrate material, an intermediate layer by physical vapor deposition (PVD) has been used to accommodate the interface stress due to the mismatch of thermal expansion or act as a diffusion barrier between the CVD-W coating and the substrate. The prepared CuCrZr/PVD-Cu/CVD-W sample with active cooling has passed thermal fatigue tests by electron beam with an absorbed power of 2.2 MW/m2, 50 s on/50 s off, for 100 cycles. Another graphite/PVD-Si/CVD-W sample without active cooling underwent thermal fatigue testing with an absorbed power density of 4.62 MW/m2, 5 s on/25 s off, for 200 cycles, and no catastrophic failure was found.

Acute-onset floaters and flashes: is this patient at risk for retinal detachment?

PubMed

Hollands, Hussein; Johnson, Davin; Brox, Anya C; Almeida, David; Simel, David L; Sharma, Sanjay

2009-11-25

Acute onset of monocular floaters and/or flashes represents a common presentation to primary care physicians, and the most likely diagnosis is posterior vitreous detachment (PVD). A significant proportion of patients with acute PVD develop an associated retinal tear that can lead to retinal detachment and permanent vision loss if left untreated. To quantify the association between relevant clinical variables and risk of retinal tear in patients presenting with acute-onset floaters and/or flashes and PVD. Structured MEDLINE (January 1950-September 2009) and EMBASE (January 1980-September 2009) searches and a hand search of references and citations of retrieved articles yielded 17 relevant studies. Studies of high-level methods that related elements of the history or physical examination in patients presenting with floaters and/or flashes and PVD to the likelihood of retinal tear. For patients with acute onset of floaters and/or flashes who are self-referred or referred to an ophthalmologist, the prevalence of retinal tear is 14% (95% confidence interval [CI], 12%-16%). Subjective visual reduction is the most important symptom associated with retinal tear (likelihood ratio [LR], 5.0; 95% CI, 3.1-8.1). Vitreous hemorrhage on slitlamp biomicroscopy is the best-studied finding with the narrowest positive LR for retinal tear (summary LR, 10; 95% CI, 5.1-20). Absence of vitreous pigment during this examination is the best-studied finding with the narrowest negative LR (summary LR, 0.23; 95% CI, 0.12-0.43). Patients initially diagnosed as having uncomplicated PVD have a 3.4% chance of a retinal tear within 6 weeks. The risk increases with new onset of at least 10 floaters (summary LR, 8.1-36) or subjective visual reduction (summary LR, 2.3-17) during this period. Primary care physicians should evaluate patients with acute-onset floaters and/or flashes due to suspected PVD, or patients with known PVD and a change in symptoms, for high-risk features of retinal tear and detachment. Physicians should always assess these patients' visual acuity. Patients at increased risk should be triaged for urgent ophthalmologic assessment.

Prefabricated Vertical Drain (PVD) and Deep Cement Mixing (DCM)/Stiffened DCM (SDCM) techniques for soft ground improvement

NASA Astrophysics Data System (ADS)

Bergado, D. T.; Long, P. V.; Chaiyaput, S.; Balasubramaniam, A. S.

2018-04-01

Soft ground improvement techniques have become most practical and popular methods to increase soil strength, soil stiffness and reduce soil compressibility including the soft Bangkok clay. This paper focuses on comparative performances of prefabricated vertical drain (PVD) using surcharge, vacuum and heat preloading as well as the cement-admixed clay of Deep Cement Mixing (DCM) and Stiffened DCM (SDCM) methods. The Vacuum-PVD can increase the horizontal coefficient of consolidation, Ch, resulting in faster rate of settlement at the same magnitudes of settlement compared to Conventional PVD. Several field methods of applying vacuum preloading are also compared. Moreover, the Thermal PVD and Thermal Vacuum PVD can increase further the coefficient of horizontal consolidation, Ch, with the associated reduction of kh/ks values by reducing the drainage retardation effects in the smear zone around the PVD which resulted in faster rates of consolidation and higher magnitudes of settlements. Furthermore, the equivalent smear effect due to non-uniform consolidation is also discussed in addition to the smear due to the mechanical installation of PVDs. In addition, a new kind of reinforced deep mixing method, namely Stiffened Deep Cement Mixing (SDCM) pile is introduced to improve the flexural resistance, improve the field quality control, and prevent unexpected failures of the Deep Cement Mixing (DCM) pile. The SDCM pile consists of DCM pile reinforced with the insertion of precast reinforced concrete (RC) core. The full scale test embankment on soft clay improved by SDCM and DCM piles was also analysed. Numerical simulations using the 3D PLAXIS Foundation finite element software have been done to understand the behavior of SDCM and DCM piles. The simulation results indicated that the surface settlements decreased with increasing lengths of the RC cores, and, at lesser extent, increasing sectional areas of the RC cores in the SDCM piles. In addition, the lateral movements decreased by increasing the lengths (longer than 4 m) and, the sectional areas of the RC cores in the SDCM piles. The results of the numerical simulations closely agreed with the observed data and successfully verified the parameters affecting the performances and behavior of both SDCM and DCM piles.

Development of a dry, stable and inhalable acyl-homoserine-lactone-acylase powder formulation for the treatment of pulmonary Pseudomonas aeruginosa infections.

PubMed

Wahjudi, Mariana; Murugappan, Senthil; van Merkerk, Ronald; Eissens, Anko C; Visser, Marinella R; Hinrichs, Wouter L J; Quax, Wim J

2013-03-12

In the lungs of cystic fibrosis (CF) patients, Pseudomonas aeruginosa commonly causes chronic infections. It has been shown that the P. aeruginosa quorum sensing (QS) system controls the expression of virulence factors during invasion and infection to host cells. PvdQ is an acyl-homoserine lactone (AHL) acylase able to degrade the signal molecule of P. aeruginosa QS. The role of PvdQ in inhibiting the QS and its successive virulence determinants has been established in in vitro as well as in in vivo, the latter in a Caenorabdhitis elegans model. For the treatment of pulmonary P. aeruginosa infections, we propose that PvdQ can be best administered directly to the lungs of the patients as a dry powder because this is expected to give specific advantages in delivery as compared to nebulizing. Therefore in this study we investigated the production of a PvdQ powder by spray-freeze drying using mannitol, trehalose and inulin as excipient. The activity of PvdQ in the powder was determined immediately after production and after subsequent storage during 4 weeks at 20°C and 55°C. We found that the enzymatic activity of PvdQ is fully maintained during spray-freeze drying using mannitol, trehalose or inulin as excipient. However, mannitol was not able to stabilize the protein during storage, while PvdQ incorporated in trehalose or inulin was fully stabilized even during storage at 55°C for at least 4 weeks. The poor stabilizing capacities of mannitol during storage could be related to its crystalline nature while the excellent stabilizing capacities of trehalose and inulin during storage could be related to their amorphous nature. The trehalose and inulin-based particles consisted of porous spheres with a volume average aerodynamical diameter of ∼1.8 μm implying that they are suitable for pulmonary delivery. This is the first study in which an AHL-degrading enzyme is processed into spray-freeze-dried powder suitable for inhalation. Copyright © 2013 Elsevier B.V. All rights reserved.

Microplasmin-Induced Posterior Vitreous Detachment Affects Vitreous Oxygen Levels

PubMed Central

Quiram, Polly A.; Leverenz, Victor R.; Baker, Robert M.; Dang, Loan; Giblin, Frauk J.; Trese, Michael T.

2009-01-01

Purpose To determine if enzymatic induction of a posterior vitreous detachment (PVD) and/or vitreous liquefaction affects O2 concentration in the vitreous cavity in animals with vascularized and avascular retinal circulations. Methods Either microplasmin or hyaluronidase was injected intravitreally into guinea pigs (avascular retinal circulation), brown Norway rats (vascularized retinal circulation without fovea), or cats (vascularized retinal circulation with fovea) with the contralateral eye used as a control. One to 2 weeks post injection, vitreal oxygen concentration was measured using a highly sensitive, platinum-based fluorophore O2 sensor. In addition, control and microplasmin-injected rats, guinea pigs, and cats were exposed to 100% oxygen and vitreal O2 levels were measured over time. Scanning electron microscopy (SEM) was used to evaluate the vitreoretinal interface for the presence of a PVD. Results In animals with a vascularized retinal circulation (brown Norway rats and cats), intravitreal injection of microplasmin with induction of a PVD significantly increased baseline O2 concentration in the vitreous cavity compared to hyaluronidase injected eyes and controls in rats (35, 25, and 23 mm Hg, P < 0.001 and P < 0.001, respectively) and cats (26, 18, and 16 mm Hg, P < 0.01 and P < 0.001, respectively). Interestingly, intravitreal injection of hyaluronidase (vitreous liquefaction without induction of a PVD) did not significantly increase vitreal O2 levels in any of the animal species (P > 0.1). Upon exposure to 100% oxygen by facemask, microplasmin injected animals showed a rapid increase in vitreal oxygen levels compared to hyaluronidase injected animals and controls, indicating that the presence of a PVD allows rapid O2 exchange within the vitreous cavity. Similarly, once O2 was discontinued, the O2 concentration decreased in a similarly rapid rate. SEM showed smooth retinal surfaces in microplasmin-injected cat eyes, indicating the presence of a PVD which was not present in hyaluronidase injected or control eyes. Conclusion The results suggest that enzymatic-assisted PVD with microplasmin increases vitreal O2 levels and increases the rate of O2 exchange within the vitreous cavity. PMID:18040251

Novel Applications of Radionuclide Imaging in Peripheral Vascular Disease

PubMed Central

Stacy, Mitchel R.; Sinusas, Albert J.

2015-01-01

Peripheral vascular disease (PVD) is a progressive atherosclerotic disease that leads to stenosis or occlusion of blood vessels supplying the lower extremities. Current diagnostic imaging techniques commonly focus on evaluation of anatomy or blood flow at the macrovascular level and do not permit assessment of the underlying pathophysiology associated with disease progression or treatment response. Molecular imaging with radionuclide-based approaches, such as PET and SPECT, can offer novel insight into PVD by providing non-invasive assessment of biological processes such as angiogenesis and atherosclerosis. This review discusses emerging radionuclide-based imaging approaches that have potential clinical applications in the evaluation of PVD progression and treatment. PMID:26590787

Characterization of Beryllium Windows for Coherent X-ray Optics

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

Goto, Shunji; Yabashi, Makina; Tamasaku, Kenji

2007-01-19

Beryllium foils fabricated by several processes were characterized using spatially coherent x rays at 1-km beamline of SPring-8. By thickness dependence of bright x-ray spot density due to Fresnel diffraction from several-micron deficiencies, we found that speckles (bright x-ray spots) were due to voids with densities 103-104 mm-3 in powder foils and ingot foils. Compared with powder and ingot foils, a polished physical-vapor-deposited (PVD) beryllium foil gave highly uniform beams with no speckles. The PVD process eliminates the internal voids in principle and the PVD foil is the best for coherent x-ray applications.

Nanospecific Inhibition of Pyoverdine Siderophore Production in Pseudomonas Chlororaphis O6 by CuO Nanoparticles

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

Dimkpa, Christian O.; McLean, Joan E.; Britt, David W.

2012-03-01

As traditional antibiotics become less effective against a growing number of pathogens, engineered nanoparticles (NPs) are becoming more widely applied as biocides. NPs of Ag, ZnO, and CuO exhibit dose-dependent antimicrobial activity; however, information is scant on the impact of sublethal levels of NPs on bacteria. In this paper, we evaluated the effect of a sublethal concentration (200 mg/L) of commercial CuO NPs on the expression of genes involved in the production of the fluorescent siderophore, pyoverdine (PVD) in the plant-beneficial bacterium Pseudomonas chlororaphis O6. PVDs are important in microbe-microbe and microbe-plant interactions, and are a virulence factor in pathogenicmore » pseudomonads. Cells challenged with the NPs had reduced amounts of PVD in their periplasm and the external medium. The NPs impaired the expression of genes involved in transport of the PVD precursor through the plasmamembrane, PVD maturation in the periplasm, and export through the outer membrane. Also, expression from one of three predicted Fe-PVD receptors was reduced by the NPs. As these effects were not observed for cells challenged with copper ions, this is a nanoparticlespecific phenomenon mediating cellular reprogramming in bacteria, affecting secondary metabolism and thus associated critical microbial processes. The regulation of bacterial genes and secondary metabolites by sublethal doses of a common metal oxide NP has strong environmental and medical implications.« less

Recommendations for Self-Report Outcome Measures in Vulvodynia Clinical Trials.

PubMed

Pukall, Caroline F; Bergeron, Sophie; Brown, Candace; Bachmann, Gloria; Wesselmann, Ursula

2017-08-01

Vulvodynia (idiopathic chronic vulvar pain) is a prevalent condition associated with significant and negative impacts in many areas of function. Despite the increased research interest in vulvodynia in recent years, recommendations for outcome measures for use in clinical trials are missing. The purpose of this paper, therefore, was to provide recommendations for outcome measures for vulvodynia clinical trials so that consistent measures are used across trials to facilitate between-study comparisons and the conduct of large multicenter trials, and to improve measurement of the multiple dimensions of vulvodynia. Given that provoked vestibulodynia (PVD)-characterized by provoked pain localized to the vaginal opening-is the most common subtype of vulvodynia and the current main focus of clinical trials, this paper focused on recommended outcome measures in PVD clinical trials. The framework used to guide the selection of outcome measures was based on the one proposed by the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT). The IMMPACT framework provided a well-suited guideline for outcome measure recommendations in PVD clinical trials. However, given the provoked presentation of PVD and the significant impact it has on sexuality, modifications to some of the IMMPACT recommendations were made and specific additional measures were suggested. Measures that are specific to vulvovaginal pain are ideal for adoption in PVD clinical trials, and many such measures currently exist that allow the relevant IMMPACT domains to be captured.

Challenging metastatic breast cancer with the natural defensin PvD1.

PubMed

Figueira, Tiago N; Oliveira, Filipa D; Almeida, Inês; Mello, Érica O; Gomes, Valdirene M; Castanho, Miguel A R B; Gaspar, Diana

2017-11-09

Metastatic breast cancer is a very serious life threatening condition that poses many challenges for the pharmaceutical development of effective chemotherapeutics. As the therapeutics targeted to the localized masses in breast improve, metastatic lesions in the brain slowly increase in their incidence compromising successful treatment outcomes overall. The blood-brain-barrier (BBB) is one important obstacle for the management of breast cancer brain metastases. New therapeutic approaches are in demand for overcoming the BBB's breaching by breast tumor cells. In this work we demonstrate the potential dual role of a natural antimicrobial plant defensin, PvD 1 : it interferes with the formation of solid tumors in the breast and concomitantly controls adhesion of breast cancer cells to human brain endothelial cells. We have used a combination of techniques that probe PvD 1 's effect at the single cell level and reveal that this peptide can effectively damage breast tumor cells, leaving healthy breast and brain cells unaffected. Results suggest that PvD1 quickly internalizes in cancer cells but remains located in the membrane of normal cells with no significant damage to its structure and biomechanical properties. These interactions in turn modulate cell adhesiveness between tumor and BBB cells. PvD 1 is a potential template for the design of innovative pharmacological approaches for metastatic breast cancer treatment: the manipulation of the biomechanical properties of tumor cells that ultimately prevent their attachment to the BBB.

Highly efficient gel-state dye-sensitized solar cells prepared using propionitrile and poly(vinylidene fluoride-co-hexafluoropropylene)

NASA Astrophysics Data System (ADS)

Venkatesan, Shanmuganathan; Hidayati, Noor; Liu, I.-Ping; Lee, Yuh-Lang

2016-12-01

Propionitrile (PPN) solvent based iodide/triiodide liquid-electrolyte is utilized to prepare highly efficient poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) polymer gel electrolytes (PGEs) of dye-sensitized solar cells, aiming at improving the energy conversion efficiency as well as the stability of gel-state DSSCs. The concentrations effect of the PVdF-HFP on the properties of PGEs and the performance of the corresponding cells are studied. The results show that the in-situ gelation is performed for the PVdF-HFP concentration range of 8-18% at room temperature. However, increasing the concentration of polymer in the PGEs triggers a decrease in the diffusivity and conductivity of the PGEs, but an increase in the phase transition temperature of the PGEs. A high phase transition temperature is obtained for the PGEs with 18 wt% PVdF-HFP, which increase the long-term stability of the gel-state DSSC. By using the 18 wt% PVdF-HFP in the presence of 5 wt% TiO2 nanofillers (NFs), gel-state cells with an efficiency of 8.38% can be obtained, which is higher than that achieved by liquid-state cells (7.55%). After 1000 h test at room temperature (RT) and 50 °C, the cell can retain 96% and 82%, respectively, of its initial efficiency.

Nanolayered Features of Collagen-like Peptides

NASA Technical Reports Server (NTRS)

Valluzzi, Regina; Bini, Elisabetta; Haas, Terry; Cebe, Peggy; Kaplan, David L.

2003-01-01

We have been investigating collagen-like model oligopeptides as molecular bases for complex ordered biomimetic materials. The collagen-like molecules incorporate aspects of native collagen sequence and secondary structure. Designed modifications to native primary and secondary structure have been incorporated to control the nanostructure and microstructure of the collagen-like materials produced. We find that the collagen-like molecules form a number of lyotropic rod liquid crystalline phases, which because of their strong temperature dependence in the liquid state can also be viewed as solvent intercalated thermotropic liquid crystals. The liquid crystalline phases formed by the molecules can be captured in the solid state by drying off solvent, resulting in solid nanopatterned (chemically and physically) thermally stable (to greater than 100 C) materials. Designed sequences which stabilize smectic phases have allowed a variety of nanoscale multilayered biopolymeric materials to be developed. Preliminary investigations suggest that chemical patterns running perpendicular to the smectic layer plane can be functionalized and used to localize a variety of organic, inorganic, and organometallic moieties in very simple multilayered nanocomposites. The phase behavior of collagen-like oligopeptide materials is described, emphasizing the correlation between mesophase, molecular orientation, and chemical patterning at the microscale and nanoscale. In many cases, the textures observed for smectic and hexatic phase collagens are remarkably similar to the complex (and not fully understood) helicoids observed in biological collagen-based tissues. Comparisons between biological morphologies and collagen model liquid crystalline (and solidified materials) textures may help us understand the molecular features which impart order and function to the extracellular matrix and to collagen-based mineralized tissues. Initial studies have utilized synthetic collagen-like peptides while future work will also focus on similar sequences generated via genetic engineering methods.

The Impact of Dopant Segregation on the Maximum Carrier Density in Si:P Multilayers.

PubMed

Keizer, Joris G; McKibbin, Sarah R; Simmons, Michelle Y

2015-07-28

Abrupt dopant profiles and low resistivity are highly sought after qualities in the silicon microelectronics industry and, more recently, in the development of an all epitaxial Si:P based quantum computer. If we increase the active carrier density in silicon to the point where the material becomes superconducting, while maintaining a low thermal budget, it will be possible to fabricate nanoscale superconducting devices using the highly successful technique of depassivation lithography. In this work, we investigate the dopant profile and activation in multiple high density Si:P δ-layers fabricated by stacking individual layers with intervening silicon growth. We determine that dopant activation is ultimately limited by the formation of P-P dimers due to the segregation of dopants between multilayers. By increasing the encapsulation thickness between subsequent layers, thereby minimizing the formation of these deactivating defects, we are able to achieve an active carrier density of ns = 4.5 ×10(14) cm(-2) for a triple layer. The results of electrical characterization are combined with those of secondary ion mass spectroscopy to construct a model that accurately describes the impact of P segregation on the final active carrier density in Si:P multilayers. Our model predicts that a 3D active carrier density of 8.5 × 10(20) cm(-3) (1.7 atom %) can be achieved.

Improving Outcomes for Pulmonary Vascular Disease

PubMed Central

Robbins, Ivan M.; Blaisdell, Carol J.; Abman, Steven H.

2012-01-01

Recognizing the importance of improving lung health through lung disease research, the National Heart, Lung, and Blood Institute (NHLBI) convened a workshop of multidisciplinary experts for the following purpose: (1) to review the current scientific knowledge underlying the basis for treatment of adults and children with pulmonary vascular diseases (PVDs); (2) to identify gaps, barriers, and emerging scientific opportunities in translational PVD research and the means to capitalize on these opportunities; (3) to prioritize new research directions that would be expected to affect the clinical course of PVDs; and (4) to make recommendations to the NHLBI on how to fill identified gaps in adult and pediatric PVD clinical research. Workshop participants reviewed experiences from previous PVD clinical trials and ongoing clinical research networks with other lung disorders, including acute respiratory distress syndrome, chronic obstructive lung disease, and idiopathic pulmonary fibrosis, as well. Bioinformatics experts discussed strategies for applying cutting-edge health information technology to clinical studies. Participants in the workshop considered approaches in the following broad concept areas: (1) improved phenotyping to identify potential subjects for appropriate PVD clinical studies; (2) identification of potential new end points for assessing key outcomes and developing better-designed PVD clinical trials; and (3) the establishment of priorities for specific clinical research needed to advance care of patients with various subsets of PVDs from childhood through adulthood. This report provides a summary of the objectives and recommendations to the NHLBI concentrating on clinical research efforts that are needed to better diagnose and treat PVDs. PMID:22335936

Fluorine incorporation into SnO2 nanoparticles by co-milling with polyvinylidene fluoride

NASA Astrophysics Data System (ADS)

Senna, Mamoru; Turianicová, Erika; Šepelák, Vladimír; Bruns, Michael; Scholz, Gudrun; Lebedkin, Sergei; Kübel, Christian; Wang, Di; Kaňuchová, Mária; Kaus, Maximilian; Hahn, Horst

2014-04-01

Fluorine was incorporated into SnO2 nanoparticles from polyvinylidene fluoride (PVdF) by co-milling. The incorporation process was triggered by an oxidative partial decomposition of PVdF due to the abstraction of oxygen atoms, and began soon after milling with a simultaneous decrease in the crystallite size of SnO2 from 56 nm to 19 nm, and increase in the lattice strain by a factor 7. Appearance of D and G Raman peaks indicated that the decomposition of PVdF was accompanied by the formation of nanometric carbon species. Decomposing processes of PVdF were accompanied by the continuous change in the states of F, with a decrease of C-F in PVdF and increase in Sn-F. This indicates the gradual incorporation of F into SnO2, by replacing a part of oxygen in the oxide with fluorine. These serial mechanochemical reaction processes were discussed on the basis of X-ray diffractometry, FT-IR, Raman and UV-Vis diffuse reflectance spectroscopy, transmission electron microscopy, F1s, Sn3d and C1s X-ray photoelectron spectroscopy and Auger electron spectra, as well as magic angle spinning NMR spectroscopy of 19F and 119Sn. The present findings serve as an initial stage of incorporating fluorine into SnO2 via a solvent-free solid-state process, toward the rational fabrication of fluorine doped SnO2 powders.

Effect of Triflusal on Primary Vascular Dysregulation Compared with Aspirin: A Double-Blind, Randomized, Crossover Trial.

PubMed

Shin, Sanghoon; Kim, Kwang-Joon; Cho, In-Jeong; Hong, Geu-Ru; Jang, Yangsoo; Chung, Namsik; Rah, Young Min; Chang, Hyuk-Jae

2015-09-01

Primary vascular dysregulation (PVD) is a condition in which the response to cold temperature or external stimuli is abnormal. We investigated whether triflusal use results in amelioration of PVD symptoms and improvement of several related parameters compared with aspirin. Eighty-eight PVD patients (54% female, 56±8 years) were randomly selected to receive either triflusal (300 mg, b.i.d.) or aspirin (150 mg, b.i.d.) for a period of 6 weeks followed by crossover. PVD was defined as both red-blood-cell standstill in video-assisted microscopic capillaroscopy during cold stimulation using carbon dioxide gas and a score of more than 7 points in a validated questionnaire. Efficacy of treatment was assessed by 1) cold intolerance symptom severity (CISS) score, 2) finger Doppler indices, and 3) indocyanine green perfusion imaging. The use of triflusal resulted in a greater improvement in CISS score (44.5±18.4 vs. 51.9±16.2; p<0.001) and in mean radial peak systolic velocity (69.8±17.2 vs. 66.1±16.4; p=0.011) compared to aspirin. Furthermore, significant differences were also observed in perfusion rates on indocyanine green perfusion imaging between triflusal and aspirin (45.6±25.8 vs. 51.6±26.9; p=0.020). Triflusal was more effective and demonstrated a more consistent impact on the improvement of symptoms and blood flow in patients with PVD than aspirin.

Nematic-like stable glasses without equilibrium liquid crystal phases

DOE Data Explorer

Gomez, Jaritza [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; Gujral, Ankit [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; Huang, Chengbin [School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705-2222, USA; Bishop, Camille [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; Yu, Lian [School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705-2222, USA; Ediger, Mark [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA

2017-02-01

We report the thermal and structural properties of glasses of posaconazole, a rod-like molecule, prepared using physical vapor deposition (PVD). PVD glasses of posaconazole can show substantial molecular orientation depending upon the choice of substrate temperature, Tsubstrate, during deposition.Ellipsometry and IR measurements indicate that glasses prepared at Tsubstrate very near the glass transition temperature (Tg) are highly ordered. For these posaconazole glasses, the orientation order parameter is similar to that observed in macroscopically aligned nematic liquid crystals, indicating that the molecules are mostly parallel to one another and perpendicular to the interface. To our knowledge, these are the most anisotropic glasses ever prepared by PVD from a molecule that does not form equilibrium liquid crystal phases. These results are consistent with a previously proposed mechanism in which molecular orientation in PVD glasses is inherited from the orientation present at the free surface of the equilibrium liquid. This mechanism suggests that molecular orientation at the surface of the equilibrium liquid of posaconazole is nematic-like. Posaconazole glasses can show very high kinetic stability; the isothermal transformation of a 400 nm glass into the supercooled liquid occurs via a propagating front that originates at the free surface and requires ~105 times the structural relaxation time of the liquid (τα). We also studied the kinetic stability of PVD glasses of itraconazole, which is a structurally similar molecule with equilibrium liquid crystal phases. While itraconazole glasses can be even more anisotropic than posaconazole glasses, they exhibit lower kinetic stability.

Tunable magnetotransport in Fe/hBN/graphene/hBN/Pt(Fe) epitaxial multilayers

NASA Astrophysics Data System (ADS)

Magnus Ukpong, Aniekan

2018-03-01

Theoretical and computational analysis of the magnetotransport properties and spin-transfer torque field-induced switching of magnetization density in vertically-stacked multilayers is presented. Using epitaxially-capped free layers of Pt and Fe, atom-resolved magnetic moments and spin-transfer torques are computed at finite bias. The calculations are performed within linear response approximation to the spin-density reformulation of the van der Waals density functional theory. Dynamical spin excitations are computed as a function of a spin-transfer torque induced magnetic field along the magnetic easy axis, and the corresponding spin polarization perpendicular to the easy axis is obtained. Bias-dependent giant anisotropic magnetoresistance of up to 3200% is obtained in the nonmagnetic-metal-capped Fe/hBN/graphene/hBN/Pt multilayer architecture. Since this specific heterostructure is not yet fabricated and characterized, the predicted high performance has not been demonstrated experimentally. Nevertheless, similar calculations performed on the Fe/hBN/Co stack show that the tunneling magnetoresistance obtained at the Fermi-level is in excellent agreement with results of recent magnetotransport measurements on magnetic tunnel junctions that contain the monolayer hBN tunnel region. The magnitude of the spin-transfer torque is found to increase as the tunneling spin current increases, and this activates the magnetization switching process due to increased charge accumulation. This mechanism causes substantial spin backflow, which manifests as rapid undulations in the bias-dependent tunneling spin currents. The implication of these findings on the design of nanoscale spintronic devices with spin-transfer torque tunable magnetization density is discussed. Insights derived from this study are expected to enhance the prospects for developing and integrating artificially assembled van der Waals multilayer heterostructures as the preferred material platform for efficient engineering of spin switches for spintronic applications.

Reactions in Electrodeposited Cu/Sn and Cu/Ni/Sn Nanoscale Multilayers for Interconnects

PubMed Central

Chia, Pay Ying; Haseeb, A. S. M. A.; Mannan, Samjid Hassan

2016-01-01

Miniaturization of electronic devices has led to the development of 3D IC packages which require ultra-small-scale interconnections. Such small interconnects can be completely converted into Cu-Sn based intermetallic compounds (IMCs) after reflow. In an effort to improve IMC based interconnects, an attempt is made to add Ni to Cu-Sn-based IMCs. Multilayer interconnects consisting of stacks of Cu/Sn/Cu/Sn/Cu or Cu/Ni/Sn/Ni/Sn/Cu/Ni/Sn/Ni/Cu with Ni = 35 nm, 70 nm, and 150 nm were electrodeposited sequentially using copper pyrophosphate, tin methanesulfonic, and nickel Watts baths, respectively. These multilayer interconnects were investigated under room temperature aging conditions and for solid-liquid reactions, where the samples were subjected to 250 °C reflow for 60 s and also 300 °C for 3600 s. The progress of the reaction in the multilayers was monitored by using X-ray Diffraction, Scanning Electron Microscope, and Energy dispersive X-ray Spectroscopy. FIB-milled samples were also prepared for investigation under room temperature aging conditions. Results show that by inserting a 70 nanometres thick Ni layer between copper and tin, premature reaction between Cu and Sn at room temperature can be avoided. During short reflow, the addition of Ni suppresses formation of Cu3Sn IMC. With increasing Ni thickness, Cu consumption is decreased and Ni starts acting as a barrier layer. On the other hand, during long reflow, two types of IMC were found in the Cu/Ni/Sn samples which are the (Cu,Ni)6Sn5 and (Cu,Ni)3Sn, respectively. Details of the reaction sequence and mechanisms are discussed. PMID:28773552

To say or not to say: Dyadic ambivalence over emotional expression and its associations with pain, sexuality, and distress in couples coping with provoked vestibulodynia.

PubMed

Awada, Nayla; Bergeron, Sophie; Steben, Marc; Hainault, Victoria-Ann; McDuff, Pierre

2014-05-01

Provoked vestibulodynia (PVD) is a highly prevalent and taxing female genital pain condition. Despite the intimate nature of this pain and the fact that affective factors such as anxiety have been shown to modulate its manifestations, no study has yet explored the emotional regulation of couples in which the woman suffers from PVD. Ambivalence over emotional expression (AEE) is an emotional regulation variable that quantifies the extent to which a person is comfortable with the way she or he expresses emotions. We examined whether the dyadic AEE of couples in which the woman suffers from PVD was differentially associated with women's pain and couples' psychological, sexual, and relational functioning. Couples (N = 254), in which the woman suffered from PVD, completed the AEE questionnaire. A couple typology of dyadic AEE was created. Dependent measures for both members of the couple were the global measure of sexual satisfaction scale, the Beck depression inventory II, and the revised dyadic adjustment scale. The female sexual function index and the sexual history form were used to assess the sexual function of women and men, respectively. Women also completed the pain rating index of the McGill pain questionnaire. Couples, in which both partners were considered low on AEE, had the highest scores on sexual satisfaction (P = 0.02) and function (P < 0.01), the lowest depression scores (P < 0.01), and the best dyadic adjustment (P = 0.02). No difference in pain intensity was found between couples. Findings suggest that, for couples in which the woman suffers from PVD, an emotional regulation that is low in ambivalence in both partners is associated with better psychological, sexual, and relational outcomes. Results indicate that emotional regulation may be important to consider in the assessment and treatment of couples coping with PVD. © 2014 International Society for Sexual Medicine.

Sexual and relationship intimacy among women with provoked vestibulodynia and their partners: associations with sexual satisfaction, sexual function, and pain self-efficacy.

PubMed

Bois, Katy; Bergeron, Sophie; Rosen, Natalie O; McDuff, Pierre; Grégoire, Catherine

2013-08-01

Provoked vestibulodynia (PVD) is the most frequent subtype of vulvodynia. Women report negative consequences of PVD on their sexual and romantic relationships. Researchers have recently highlighted the importance of examining interpersonal factors such as intimacy, and of including both women and their partners in study designs. The aim of this study was to investigate sexual and relationship intimacy as defined by the Interpersonal Process Model of Intimacy and their associations with sexual satisfaction, sexual function, pain self-efficacy, and pain intensity among women with PVD and their partners. Ninety-one heterosexual women (M age = 27.38, SD = 6.04) diagnosed with PVD and their partners (M age = 29.37, SD = 7.79) completed measures of sexual and relationship intimacy, sexual satisfaction, sexual function, pain self-efficacy, and pain intensity. Dependent measures were the (i) Global Measure of Sexual Satisfaction Scale; (ii) Female Sexual Function Index; (iii) Painful Intercourse Self-Efficacy Scale; and (iv) visual analog scale of pain intensity during intercourse. After controlling for women's age, women's greater sexual intimacy (β = 0.49, P < 0.001) was associated with women's greater sexual satisfaction and higher pain self-efficacy (β = 0.39, P = 0.001), beyond the effects of partners' sexual intimacy. Also, women's greater sexual intimacy (β = 0.24, P = 0.05) and women's greater relationship intimacy (β = 0.54, P = 0.003) were associated with greater women's sexual function, beyond the effects of partners' sexual and relationship intimacy. Women's self-reported sexual and relationship intimacy in the couple relationship may promote higher sexual satisfaction, sexual function, and pain self-efficacy, as well as possibly foster greater sexual well-being among women with PVD. The authors discuss implications for the inclusion of emotional and interpersonal aspects of the couple's dynamic in clinical interventions and future research in PVD. © 2013 International Society for Sexual Medicine.

Women with provoked vestibulodynia experience clinically significant reductions in pain regardless of treatment: results from a 2-year follow-up study.

PubMed

Davis, Seth N P; Bergeron, Sophie; Binik, Yitzchak M; Lambert, Bernard

2013-12-01

Provoked vestibulodynia (PVD) is a prevalent genital pain syndrome that has been assumed to be chronic, with little spontaneous remission. Despite this assumption, there is a dearth of empirical evidence regarding the progression of PVD in a natural setting. Although many treatments are available, there is no single treatment that has demonstrated efficacy above others. The aims of this secondary analysis of a prospective study were to (i) assess changes over a 2-year period in pain, depressive symptoms, and sexual outcomes in women with PVD; and (ii) examine changes based on treatment(s) type. Participants completed questionnaire packages at Time 1 and a follow-up package 2 years later. Visual analog scale of genital pain, Global Measure of Sexual Satisfaction, Female Sexual Function Index, Beck Depression Inventory, Dyadic Adjustment Scale, and sexual intercourse attempts over the past month. Two hundred thirty-nine women with PVD completed both time one and two questionnaires. For the sample as a whole, there was significant improvement over 2 years on pain ratings, sexual satisfaction, sexual function, and depressive symptoms. The most commonly received treatments were physical therapy, sex/psychotherapy, and medical treatment, although 41.0% did not undergo any treatment. Women receiving no treatment also improved significantly on pain ratings. No single treatment type predicted better outcome for any variable except depressive symptoms, in which women who underwent surgery were more likely to improve. These results suggest that PVD may significantly reduce in severity over time. Participants demonstrated clinically significant pain improvement, even when they did not receive treatment. Furthermore, the only single treatment type predicting better outcomes was surgery, and only for depressive symptoms, accounting for only 2.3% of the variance. These data do not demonstrate the superiority of any one treatment and underscore the need to have control groups in PVD treatment trials, otherwise improvements may simply be the result of natural progression. © 2013 International Society for Sexual Medicine.

Woman and partner-perceived partner responses predict pain and sexual satisfaction in provoked vestibulodynia (PVD) couples.

PubMed

Rosen, Natalie O; Bergeron, Sophie; Leclerc, Bianca; Lambert, Bernard; Steben, Marc

2010-11-01

Provoked vestibulodynia (PVD) is a highly prevalent vulvovaginal pain condition that results in significant sexual dysfunction, psychological distress, and reduced quality of life. Although some intra-individual psychological factors have been associated with PVD, studies to date have neglected the interpersonal context of this condition. We examined whether partner responses to women's pain experience-from the perspective of both the woman and her partner-are associated with pain intensity, sexual function, and sexual satisfaction. One hundred ninety-one couples (M age for women=33.28, standard deviation [SD]=12.07, M age for men=35.79, SD=12.44) in which the woman suffered from PVD completed the spouse response scale of the Multidimensional Pain Inventory, assessing perceptions of partners' responses to the pain. Women with PVD also completed measures of pain, sexual function, sexual satisfaction, depression, and dyadic adjustment. Dependent measures were women's responses to: (i) a horizontal analog scale assessing the intensity of their pain during intercourse; (ii) the Female Sexual Function Index; and (iii) the Global Measure of Sexual Satisfaction Scale. Controlling for depression, higher solicitous partner responses were associated with higher levels of women's vulvovaginal pain intensity. This association was significant for partner-perceived responses (β=0.29, P<0.001) and for woman-perceived partner responses (β=0.16, P=0.04). After controlling for sexual function and dyadic adjustment, woman-perceived greater solicitous partner responses (β=0.16, P=0.02) predicted greater sexual satisfaction. Partner-perceived responses did not predict women's sexual satisfaction. Partner responses were not associated with women's sexual function. Findings support the integration of dyadic processes in the conceptualization and treatment of PVD by suggesting that partner responses to pain affect pain intensity and sexual satisfaction in affected women. © 2010 International Society for Sexual Medicine.

Associations Between Penetration Cognitions, Genital Pain, and Sexual Well-being in Women with Provoked Vestibulodynia.

PubMed

Anderson, Alexandra B; Rosen, Natalie O; Price, Lisa; Bergeron, Sophie

2016-03-01

Provoked vestibulodynia (PVD) is a common vulvovaginal pain condition that negatively impacts women's psychological and sexual well-being. Controlled studies have found that women with PVD report greater negative and less positive cognitions about penetration; however, associations between these types of cognitions and women's pain and sexual well-being remain unknown. Further, researchers have yet to examine how interpersonal variables such as sexual communication may impact the association between women's penetration cognitions and PVD outcomes. We examined associations between vaginal penetration cognitions and sexual satisfaction, sexual function, and pain in women with PVD, as well as the moderating role of sexual communication. Seventy-seven women (M age = 28.32, SD = 6.19) diagnosed with PVD completed the catastrophic and pain cognitions and positive cognitions subscales of the Vaginal Penetration Cognition Questionnaire, as well as the Dyadic Sexual Communication Scale. Participants also completed measures of sexual satisfaction, sexual function, and pain. Dependent measures were the (i) Global Measure of Sexual Satisfaction Scale; (ii) Female Sexual Function Index; and (iii) Present Pain Intensity scale of the McGill Pain Questionnaire, with reference to pain during vaginal intercourse. Women's lower catastrophic and pain cognitions, higher positive cognitions, and higher sexual communication were each uniquely associated with higher sexual satisfaction and sexual function. Lower catastrophic and pain cognitions also were associated with women's lower pain. For women who reported higher sexual communication, as positive cognitions increased, there was a significantly greater decrease in pain intensity during intercourse compared to women who reported lower levels of sexual communication. Findings may inform cognitive-behavioral interventions aimed at improving the pain and sexual well-being of women with PVD. Targeting the couple's sexual communication and women's penetration cognitions may improve women's sexual adjustment and reduce pain. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

The primary vascular dysregulation syndrome: implications for eye diseases

PubMed Central

2013-01-01

Vascular dysregulation refers to the regulation of blood flow that is not adapted to the needs of the respective tissue. We distinguish primary vascular dysregulation (PVD, formerly called vasospastic syndrome) and secondary vascular dysregulation (SVD). Subjects with PVD tend to have cold extremities, low blood pressure, reduced feeling of thirst, altered drug sensitivity, increased pain sensitivity, prolonged sleep onset time, altered gene expression in the lymphocytes, signs of oxidative stress, slightly increased endothelin-1 plasma level, low body mass index and often diffuse and fluctuating visual field defects. Coldness, emotional or mechanical stress and starving can provoke symptoms. Virtually all organs, particularly the eye, can be involved. In subjects with PVD, retinal vessels are stiffer and more irregular, and both neurovascular coupling and autoregulation capacity are reduced while retinal venous pressure is often increased. Subjects with PVD have increased risk for normal-tension glaucoma, optic nerve compartment syndrome, central serous choroidopathy, Susac syndrome, retinal artery and vein occlusions and anterior ischaemic neuropathy without atherosclerosis. Further characteristics are their weaker blood–brain and blood-retinal barriers and the higher prevalence of optic disc haemorrhages and activated astrocytes. Subjects with PVD tend to suffer more often from tinnitus, muscle cramps, migraine with aura and silent myocardial ischaemic and are at greater risk for altitude sickness. While the main cause of vascular dysregulation is vascular endotheliopathy, dysfunction of the autonomic nervous system is also involved. In contrast, SVD occurs in the context of other diseases such as multiple sclerosis, retrobulbar neuritis, rheumatoid arthritis, fibromyalgia and giant cell arteritis. Taking into consideration the high prevalence of PVD in the population and potentially linked pathologies, in the current article, the authors provide recommendations on how to effectively promote the field in order to create innovative diagnostic tools to predict the pathology and develop more efficient treatment approaches tailored to the person. PMID:23742177

Posterior hyaloid detachment and internal limiting membrane peeling assisted by anthocyanins from acai fruit (Euterpe oleracea) and 10 other natural vital dyes: experimental study in cadaveric eyes.

PubMed

Chen, Jane; Ferreira, Magno Antonio; Farah, Michel Eid; de Carvalho, André Maia; Alves Ferreira, Raquel Eustaquio; de Moraes Filho, Milton Nunes; Souza Lima-Filho, Acácio Alves; Lago, João Henrique G; Sartorelli, Patricia; Rodrigues, Eduardo Buchele; Ferreira, Eber; Peris, Cristiane; Maia, Maurício

2013-01-01

The purpose of this study was to determine whether natural dyes facilitate posterior hyaloid detachment (posterior vitreous detachment [PVD]) and retinal internal limiting membrane (ILM) peeling in human eyes. Open-sky vitrectomy with posterior hyaloid and ILM removal was performed in 86 human cadaveric eyes. After core vitrectomy, 11 different dyes were injected into the vitreous cavity to aid hyaloid detachment and ILM removal. The dyes were allowed to settle on the macula for 5 minutes after PVD and were removed by mechanical aspiration. Intraocular forceps were used for ILM peeling, which was confirmed by light microscopy of the peeled tissue. Acai fruit (Euterpe oleracea) extract and 10 additional dyes from plants or animal sources were tested: pomegranate (Punica granatum), logwood (Haematoxylum campechianum), chlorophyll extract from alfalfa (Medicago sativa), cochineal (Dactylopius coccus), hibiscus (Hibiscus rosa-sinensis), indigo (Indigofera tinctoria), paprika (Capiscum annuum), turmeric (Curcuma longa), old fustic (Maclura tinctoria), and grape (Vitis vinifera). The dyes facilitated PVD and ILM peeling. Acai fruit (E. oleracea) extract, logwood (H. campechianum), cochineal (D. coccus), and old fustic (M. tinctoria) facilitated PVD in all cases; dye-assisted PVD was compared with triamcinolone-assisted PVD performed previously in a comparative model. Acai fruit (E. oleracea) extract, cochineal (D. coccus), and chlorophyll extract from alfalfa (M. sativa) showed the best capability for ILM staining; dye-assisted ILM removal was compared with the ILM peeling guided by indocyanine green staining performed previously in a comparative model. Light microscopy confirmed the ILM removal in all cases. Anthocyanin dye of the acai fruit (E. oleracea) and the dyes from cochineal (D. coccus) and chlorophyll extract from alfalfa (M. sativa) resulted in the best capability for posterior hyaloid and ILM staining in human cadaveric eyes and may be a useful tool for vitreoretinal surgery.

Perceptual visual dysfunction, physical impairment and quality of life in Bangladeshi children with cerebral palsy.

PubMed

Mitry, D; Williams, C; Northstone, K; Akter, A; Jewel, J; Khan, N; Muhit, M; Gilbert, C E; Bowman, R

2016-09-01

Cerebral palsy (CP) is the most common cause of motor disability in children and is often accompanied by sensory and/or cognitive impairment. The aim of this study was to characterise visual acuity impairment, perceptual visual dysfunction (PVD) and physical disability in a community-based sample of Bangladeshi children with CP and to assess the impact of these factors on the quality of life of the children. A key informant study was used to recruit children with CP from Sirajganj district. Gross Motor Function Classification System (GMFCS) levels and visual impairment were assessed by a physiotherapist and an optometrist, respectively. Assessments of visual perception were performed and standardised questionnaires were administered to each child's main carer to elicit indicators of PVD and parent-reported health-related quality of life. A generalised linear regression analysis was conducted to assess the determinants of the quality of life scores. 180 children were recruited. The median age was 8 years (IQR: 6-11 years); 112 (62%) were male; 57 (32%) had visual acuity impairment and 95 (53%) had some parent-reported PVD. In analyses adjusted for age, sex, GMFCS and acuity impairment, visual attention (p<0.001) and recognition/navigation (p<0.001) were associated with total health-related quality of life, and there were similar trends for total PVD score (p=0.006) and visual search (p=0.020). PVD is an important contributor in reducing quality of life in children with CP, independent of motor disability and acuity impairment. Better characterisation of PVD is important to help design interventions for affected children, which may improve their quality of life. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Nanoscale Engineering of Efficient Oxygen Reduction Electrocatalysts by Tailoring the Local Chemical Environment of Pt Surface Sites

DOE PAGES

Cleve, Tim Van; Moniri, Saman; Belok, Gabrielle; ...

2016-11-16

The oxygen reduction reaction is the limiting half-reaction in hydrogen fuel cells. While Pt is the most active single component electrocatalyst for the reaction, it is hampered by high cost and low reaction rates. Most research to overcome these limitations has focused on Pt/3d alloys, which offer higher rates and lower cost. Here, we have synthesized, characterized, and tested alloy materials belonging to a multilayer family of electrocatalysts. The multilayer alloy materials contain an AuCu alloy core of precise composition, surrounded by Au layers and covered by a catalytically active Pt surface layer. Their performance relative to that of themore » commercial Pt standards reaches up to 4 times improved area-specific activity. Characterization studies support the hypothesis that the activity improvement originates from a combination of Au–Pt ligand effects and local strain effects manipulated through the AuCu alloy core. The approach we present to control the strain and ligand effects in the synthesis of Pt-based alloys for the ORR is very general and could lead to promising alloy materials.« less

All-optical tunable dual Fano resonance in nonlinear metamaterials in optical communication range

NASA Astrophysics Data System (ADS)

Zhou, Yi; Hu, Xiaoyong; Li, Chong; Yang, Hong; Gong, Qihuang

2018-01-01

Low-power, ultra-fast all-optical tunable dual Fano resonance was realized in a metamaterial coated with a non-linear nanocomposite layer composed of gold nanoparticle-doped polycrystalline barium strontium titanate and multilayer tungsten disulphide microsheets. A high non-linear refractive index of -2.148 × 10-11 m2/W was achieved in the nanocomposite material that originated in the non-linearity enhancement associated with the quantum confinement effect, the local-field enhancement effect, and reinforced interactions between photons and the multilayer tungsten disulphide microsheets. An ultra-low threshold pump intensity of 600 kW/cm2 was obtained. An ultra-fast response time of 25.4 ps was maintained because of the fast relaxation dynamics of the bound electrons in the nanoscale polycrystalline barium strontium titanate grains. The large third-order non-linear responses of the metamaterial were confirmed with a high third harmonic generation conversion efficiency of 5.4 × 10-5. This work may help to pave the way towards realization of ultra-high-speed information processing chips and multifunctional integrated photonic devices based on metamaterials.

Interacting dark resonances with plasmonic meta-molecules

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

Jha, Pankaj K.; Mrejen, Michael; Kim, Jeongmin

2014-09-15

Dark state physics has led to a variety of remarkable phenomena in atomic physics, quantum optics, and information theory. Here, we investigate interacting dark resonance type physics in multi-layered plasmonic meta-molecules. We theoretically demonstrate that these plasmonic meta-molecules exhibit sub-natural spectral response, analogous to conventional atomic four-level configuration, by manipulating the evanescent coupling between the bright and dark elements (plasmonic atoms). Using cascaded coupling, we show nearly 4-fold reduction in linewidth of the hybridized resonance compared to a resonantly excited single bright plasmonic atom with same absorbance. In addition, we engineered the geometry of the meta-molecules to realize efficient intramolecularmore » excitation transfer with nearly 80%, on resonant excitation, of the total absorption being localized at the second dark plasmonic atom. An analytical description of the spectral response of the structure is presented with full electrodynamics simulations to corroborate our results. Such multilayered meta-molecules can bring a new dimension to higher quality factor plasmonic resonance, efficient excitation transfer, wavelength demultiplexing, and enhanced non-linearity at nanoscale.« less

Observation of the Gap Distribution on Multi-layered Cuprate Superconductor Ba2Ca4Cu5O10(O1-x, Fx)2 by STM/STS

NASA Astrophysics Data System (ADS)

Sugimoto, Akira; Ekino, Toshikazu; Tanaka, Katsuhiro; Mineta, Kyohei; Tanabe, Kenji; Tokiwa, Kazuyasu

The nano-scale spatial gap distributions on apical-fluorine multi-layered cuprate superconductors Ba2Ca4Cu5O10(O1-x, Fx) (F0245, Tc = 70 K) are investigated by scanning tunneling microscopy/spectroscopy (STM/STS). The STM image shows randomly-distributed bright spot structures, which are assigned to the non-replaced apical oxygen. The dI/dV tunnel spectra show the coexistence of two kinds of the gap structures. The magnitudes of these gaps at 4.9 K are about ΔS ∼25 meV and ΔL ∼78 meV, respectively. The ΔL map shows the inhomogeneous distribution with the characteristic length of ∼1 nm. The smaller ΔL gap regions tend to locate at the bright-spot positions, indicating that the apical oxygen causes reduction of ΔL. These results are consistent with the well known relation between the carrier doping level and macroscopically observed gap size.

Nanoscale linear permittivity imaging based on scanning nonlinear dielectric microscopy

NASA Astrophysics Data System (ADS)

Hiranaga, Yoshiomi; Chinone, Norimichi; Cho, Yasuo

2018-05-01

A nanoscale linear permittivity imaging method based on scanning nonlinear dielectric microscopy (SNDM) was developed. The ∂C/∂z-mode SNDM (∂C/∂z-SNDM) technique described herein employs probe-height modulation to suppress disturbances originating from stray capacitance and to improve measurement stability. This method allows local permittivity distributions to be examined with extremely low noise levels (approximately 0.01 aF) by virtue of the highly sensitive probe. A cross-section of a multilayer oxide film was visualized using ∂C/∂z-SNDM as a demonstration, and numerical simulations of the response signals were conducted to gain additional insights. The experimental signal intensities were found to be in a good agreement with the theoretical values, with the exception of the background components, demonstrating that absolute sample permittivity values could be determined. The signal profiles near the boundaries between different dielectrics were calculated using various vibration amplitudes and the boundary transition widths were obtained. The beneficial aspects of higher-harmonic response imaging are discussed herein, taking into account assessments of spatial resolution and quantitation.

Nanoscale linear permittivity imaging based on scanning nonlinear dielectric microscopy.

PubMed

Hiranaga, Yoshiomi; Chinone, Norimichi; Cho, Yasuo

2018-05-18

A nanoscale linear permittivity imaging method based on scanning nonlinear dielectric microscopy (SNDM) was developed. The ∂C/∂z-mode SNDM (∂C/∂z-SNDM) technique described herein employs probe-height modulation to suppress disturbances originating from stray capacitance and to improve measurement stability. This method allows local permittivity distributions to be examined with extremely low noise levels (approximately 0.01 aF) by virtue of the highly sensitive probe. A cross-section of a multilayer oxide film was visualized using ∂C/∂z-SNDM as a demonstration, and numerical simulations of the response signals were conducted to gain additional insights. The experimental signal intensities were found to be in a good agreement with the theoretical values, with the exception of the background components, demonstrating that absolute sample permittivity values could be determined. The signal profiles near the boundaries between different dielectrics were calculated using various vibration amplitudes and the boundary transition widths were obtained. The beneficial aspects of higher-harmonic response imaging are discussed herein, taking into account assessments of spatial resolution and quantitation.

Effects of interface morphology and TGO thickness on residual stress of EB-PVD thermal barrier coatings

NASA Astrophysics Data System (ADS)

Chen, Jianwei; Zhao, Yang; Ma, Jian

2015-04-01

The residual stress of electron beam-physical vapor deposition (EB-PVD) thermal barrier coatings (TBC) is complex and difficult to be obtained. In this paper, the interface morphology of TBCs subjected to cyclic heating and cooling was observed by SEM. Based on the thermal elastic-plastic finite method, corresponding interface model of TBCs was established. The residual stress of EB-PVD TBCs with different interface morphologies and TGO thicknesses was calculated using the FE method without regard to the presence of cracks and defects. The result shows that the distribution of residual stress is significantly affected by the interface morphology, and the growth of TGO also has influence on the residual stress of TC and TGO.

Polyelectrolyte multilayer-assisted fabrication of non-periodic silicon nanocolumn substrates for cellular interface applications

NASA Astrophysics Data System (ADS)

Lee, Seyeong; Kim, Dongyoon; Kim, Seong-Min; Kim, Jeong-Ah; Kim, Taesoo; Kim, Dong-Yu; Yoon, Myung-Han

2015-08-01

Recent advances in nanostructure-based biotechnology have resulted in a growing demand for vertical nanostructure substrates with elaborate control over the nanoscale geometry and a high-throughput preparation. In this work, we report the fabrication of non-periodic vertical silicon nanocolumn substrates via polyelectrolyte multilayer-enabled randomized nanosphere lithography. Owing to layer-by-layer deposited polyelectrolyte adhesives, uniformly-separated polystyrene nanospheres were securely attached on large silicon substrates and utilized as masks for the subsequent metal-assisted silicon etching in solution. Consequently, non-periodic vertical silicon nanocolumn arrays were successfully fabricated on a wafer scale, while each nanocolumn geometric factor, such as the diameter, height, density, and spatial patterning, could be fully controlled in an independent manner. Finally, we demonstrate that our vertical silicon nanocolumn substrates support viable cell culture with minimal cell penetration and unhindered cell motility due to the blunt nanocolumn morphology. These results suggest that vertical silicon nanocolumn substrates may serve as a useful cellular interface platform for performing a statistically meaningful number of cellular experiments in the fields of biomolecular delivery, stem cell research, etc.Recent advances in nanostructure-based biotechnology have resulted in a growing demand for vertical nanostructure substrates with elaborate control over the nanoscale geometry and a high-throughput preparation. In this work, we report the fabrication of non-periodic vertical silicon nanocolumn substrates via polyelectrolyte multilayer-enabled randomized nanosphere lithography. Owing to layer-by-layer deposited polyelectrolyte adhesives, uniformly-separated polystyrene nanospheres were securely attached on large silicon substrates and utilized as masks for the subsequent metal-assisted silicon etching in solution. Consequently, non-periodic vertical silicon nanocolumn arrays were successfully fabricated on a wafer scale, while each nanocolumn geometric factor, such as the diameter, height, density, and spatial patterning, could be fully controlled in an independent manner. Finally, we demonstrate that our vertical silicon nanocolumn substrates support viable cell culture with minimal cell penetration and unhindered cell motility due to the blunt nanocolumn morphology. These results suggest that vertical silicon nanocolumn substrates may serve as a useful cellular interface platform for performing a statistically meaningful number of cellular experiments in the fields of biomolecular delivery, stem cell research, etc. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02384j

Approach and Avoidance Sexual Goals in Couples with Provoked Vestibulodynia: Associations with Sexual, Relational, and Psychological Well-Being.

PubMed

Rosen, Natalie O; Muise, Amy; Bergeron, Sophie; Impett, Emily A; Boudreau, Gillian K

2015-08-01

Provoked vestibulodynia (PVD) is a prevalent vulvovaginal pain condition that is triggered primarily during sexual intercourse. PVD adversely impacts women's and their partners' sexual relationship and psychological well-being. Over 80% of women with PVD continue to have intercourse, possibly because of sexual goals that include wanting to pursue desirable outcomes (i.e., approach goals; such as a desire to maintain intimacy) and avoid negative outcomes (i.e., avoidance goals; such as avoiding a partner's disappointment). The aim of this study was to investigate associations between approach and avoidance sexual goals and women's pain, as well as the sexual, relational, and psychological well-being of affected couples. Women with PVD (N = 107) and their partners completed measures of sexual goals, sexual satisfaction, relationship satisfaction, and depression. Women also completed measures of pain during intercourse and sexual functioning. (1) Global Measure of Sexual Satisfaction Scale, (2) Dyadic Adjustment Scale-Revised or the Couple Satisfaction Index, (3) Beck Depression Inventory-II, (4) numerical rating scale of pain during intercourse, and (5) Female Sexual Function Index. When women reported higher avoidance sexual goals, they reported lower sexual and relationship satisfaction, and higher levels of depressive symptoms. In addition, when partners of women reported higher avoidance sexual goals, they reported lower relationship satisfaction. When women reported higher approach sexual goals, they also reported higher sexual and relationship satisfaction. Targeting approach and avoidance sexual goals could enhance the quality and efficacy of psychological couple interventions for women with PVD and their partners. © 2015 International Society for Sexual Medicine.

Neonatal outcome of very preterm twins: policy of planned vaginal or cesarean delivery.

PubMed

Sentilhes, Loïc; Oppenheimer, Anne; Bouhours, Anne-Charlotte; Normand, Estelle; Haddad, Bassam; Descamps, Philippe; Marpeau, Loïc; Goffinet, François; Kayem, Gilles

2015-07-01

The objective of the study was to compare neonatal mortality and morbidity in very preterm twins with the first twin in cephalic presentation in hospitals with a policy of planned vaginal delivery (PVD) and those with a policy of planned cesarean delivery (PCD). Women with preterm cephalic first twins delivered after preterm labor and/or premature preterm rupture of membranes from 26(0/7) to 31(6/7) weeks of gestation were identified from the databases of 6 perinatal centers and classified as PVD or PCD according to the center's management policy from 1999 to 2010. Severe neonatal morbidity was defined as any of the following: intraventricular hemorrhage grades 3-4, periventricular leukomalacia, necrotizing enterocolitis, bronchopulmonary dysplasia, and hospital death. The independent effect of the planned mode of delivery, defined by the center's management policy, was tested and quantified with a 2-level multivariable logistic regression. The PVD group included 248 women, and the PCD group 63. Maternal characteristics did not differ between the 2 groups. The rate of vaginal delivery was 85.9% (213 of 248) vs 20.6% (13 of 63) (P < .001), and the rate of cesarean delivery for the second twin was 1.6% (4 of 248) vs 4.8% (3 of 63) (P = .13) for PVD and PCD. PVD had no independent effect on either newborn hospital mortality or severe neonatal composite morbidity. A policy of planned vaginal delivery of very preterm twins with the first twin in cephalic presentation does not increase either severe neonatal morbidity or mortality. Copyright © 2015 Elsevier Inc. All rights reserved.

Psychological Distress in Patients with Symptomatic Vitreous Floaters

PubMed Central

Yim, Kyung Mi; Seong, Su Jeong

2017-01-01

Purpose To evaluate the degree of psychological distress in symptomatic vitreous floater patients and to evaluate whether these psychological factors are associated with the severity of discomfort associated with vitreous floaters. Methods We recruited 61 patients with symptomatic vitreous floaters and 34 controls. The degree of posterior vitreous detachment (PVD) was evaluated using optical coherence tomography. We measured the level of depression, perceived stress, state, and trait anxiety and the degree of floater-associated discomfort with self-administered questionnaire. We compared psychological parameters between floater patients and control. We also compared clinical and psychological characteristics among different floater-associated discomfort severity groups. Results Symptomatic vitreous floater patients showed higher rate of complete PVD and higher psychological distress compared to the control. On multiple logistic regression analysis, complete PVD (p = 0.001), depression (p = 0.001), and younger age (p = 0.037) were significantly associated with symptomatic floaters. There were no significant differences in complete PVD rate among different discomfort groups, while severe discomfort group showed higher depression, perceived stress, and state and trait anxiety compared to the other two milder symptom groups. Conclusions Symptomatic vitreous floater patients showed substantial level of psychological distress, and the severity of floater symptoms was significantly associated with psychological distress. PMID:29375909

Psychological Distress in Patients with Symptomatic Vitreous Floaters.

PubMed

Kim, Yong-Kyu; Moon, Su Young; Yim, Kyung Mi; Seong, Su Jeong; Hwang, Jae Yeon; Park, Sung Pyo

2017-01-01

To evaluate the degree of psychological distress in symptomatic vitreous floater patients and to evaluate whether these psychological factors are associated with the severity of discomfort associated with vitreous floaters. We recruited 61 patients with symptomatic vitreous floaters and 34 controls. The degree of posterior vitreous detachment (PVD) was evaluated using optical coherence tomography. We measured the level of depression, perceived stress, state, and trait anxiety and the degree of floater-associated discomfort with self-administered questionnaire. We compared psychological parameters between floater patients and control. We also compared clinical and psychological characteristics among different floater-associated discomfort severity groups. Symptomatic vitreous floater patients showed higher rate of complete PVD and higher psychological distress compared to the control. On multiple logistic regression analysis, complete PVD ( p = 0.001), depression ( p = 0.001), and younger age ( p = 0.037) were significantly associated with symptomatic floaters. There were no significant differences in complete PVD rate among different discomfort groups, while severe discomfort group showed higher depression, perceived stress, and state and trait anxiety compared to the other two milder symptom groups. Symptomatic vitreous floater patients showed substantial level of psychological distress, and the severity of floater symptoms was significantly associated with psychological distress.

Are there still roles for exocrine bladder drainage and portal venous drainage for pancreatic allografts?

PubMed

Young, Carlton J

2009-02-01

Controversy remains regarding the best methodology of handling exocrine pancreatic fluid and pancreatic venous effluent. Bladder drainage has given way to enteric drainage. However, is there an instance in which bladder drainage is preferable? Also, hyperinsulinemia, as a result of systemic venous drainage (SVD), is claimed to be proatherosclerotic, whereas portal venous drainage (PVD) is more physiologic and less atherosclerotic. Bladder drainage remains a viable method of exocrine pancreas drainage, but evidence is sparse that measuring urinary amylase has a substantial benefit in the early detection of acute rejection in all types of pancreas transplants. Currently, there is no incontrovertible evidence that systemic hyperinsulinemia is proatherosclerotic, whereas recent metabolic studies on SVD and PVD showed that there was no benefit to PVD. Given the advent of newer immunosuppressive agents and overall lower acute rejection rates, the perceived benefit of bladder drainage as a means to measure urinary amylase as an early marker of rejection has not been substantiated. However, there may be a selective role for bladder drainage in 'high risk' pancreases. Also, without a clear-cut metabolic benefit to PVD over SVD, it remains the surgeon's choice as to which method to use.

Neurodevelopmental outcome of twins at two years of age according to the planned mode of delivery.

PubMed

Dekeunink, Ghislaine M M; Goossens, Simone M T A; Matthijs, van der Garde; Senden, Rachel H J; Beckers, Cynthia M J; Roumen, Frans J M E

2016-01-01

To determine neurodevelopment at two years in twins. At two years of age, all twins ≥32 weeks, delivered in our center and not randomized in the Twin Birth Study, underwent a neurodevelopment screen using the Ages and Stages Questionnaire (ASQ). Children with ≥1 abnormal ASQ domain score were evaluated by a pediatrician. Results were documented according to a planned cesarean section (PCS) or a planned vaginal delivery (PVD). An ASQ was obtained from 185 children (67%). No significant differences in percentages of abnormal scores were found between the PCS group and the PVD group or between twins A and B. Pediatric assessment revealed three children with a neurodevelopmental delay. Five other children were already under pediatric or general practitioner care for other reasons. One child with a congenital anomaly was born by a PCS, two twins A and five twins B were born in the PVD group. ASQ screening revealed no significant differences in abnormal neurodevelopment in twins at two years of age according to the mode of delivery. Pediatric assessment suggested an increased incidence for abnormal neurodevelopment in twins B born by PVD.

PVD TBC experience on GE aircraft engines

NASA Technical Reports Server (NTRS)

Bartz, A.; Mariocchi, A.; Wortman, D. J.

1995-01-01

The higher performance levels of modern gas turbine engines present significant challenges in the reliability of materials in the turbine. The increased engine temperatures required to achieve the higher performance levels reduce the strength of the materials used in the turbine sections of the engine. Various forms of Thermal Barrier Coatings (TBC's) have been used for many years to increase the reliability of gas turbine engine components. Recent experience with the Physical Vapor Deposition (PVD) process using ceramic material has demonstrated success in extending the service life of turbine blades and nozzles. Engine test results of turbine components with a 125 micrometer (0.005 in) PVD TBC have demonstrated component operating temperatures of 56-83 C (100-150 F) lower than uncoated components. Engine testing has also revealed the TBC is susceptible to high angle particle impact damage. Sand particles and other engine debris impact the TBC surface at the leading edge of airfoils and fracture the PVD columns. As the impacting continues the TBC erodes away in local areas. Analysis of the eroded areas has shown a slight increase in temperature over a fully coated area, however, a significant temperature reduction was realized over an airfoil without any TBC.

PVD TBC experience on GE aircraft engines

NASA Astrophysics Data System (ADS)

Maricocchi, A.; Bartz, A.; Wortman, D.

1997-06-01

The higher performance levels of modern gas turbine engines present significant challenges in the reli-ability of materials in the turbine. The increased engine temperatures required to achieve the higher per-formance levels reduce the strength of the materials used in the turbine sections of the engine. Various forms of thermal barrier coatings have been used for many years to increase the reliability of gas turbine engine components. Recent experience with the physical vapor deposition process using ceramic material has demonstrated success in extending the service life of turbine blades and nozzles. Engine test results of turbine components with a 125 μm (0.005 in.) PVD TBC have demonstrated component operating tem-peratures of 56 to 83 °C (100 to 150 °F) lower than non-PVD TBC components. Engine testing has also revealed that TBCs are susceptible to high angle particle impact damage. Sand particles and other engine debris impact the TBC surface at the leading edge of airfoils and fracture the PVD columns. As the impacting continues, the TBC erodes in local areas. Analysis of the eroded areas has shown a slight increase in temperature over a fully coated area ; however, a significant temperature reduc-tion was realized over an airfoil without TBC.

An RGB colour image steganography scheme using overlapping block-based pixel-value differencing

PubMed Central

Pal, Arup Kumar

2017-01-01

This paper presents a steganographic scheme based on the RGB colour cover image. The secret message bits are embedded into each colour pixel sequentially by the pixel-value differencing (PVD) technique. PVD basically works on two consecutive non-overlapping components; as a result, the straightforward conventional PVD technique is not applicable to embed the secret message bits into a colour pixel, since a colour pixel consists of three colour components, i.e. red, green and blue. Hence, in the proposed scheme, initially the three colour components are represented into two overlapping blocks like the combination of red and green colour components, while another one is the combination of green and blue colour components, respectively. Later, the PVD technique is employed on each block independently to embed the secret data. The two overlapping blocks are readjusted to attain the modified three colour components. The notion of overlapping blocks has improved the embedding capacity of the cover image. The scheme has been tested on a set of colour images and satisfactory results have been achieved in terms of embedding capacity and upholding the acceptable visual quality of the stego-image. PMID:28484623

Expanding the molecular-ruler process through vapor deposition of hexadecanethiol

PubMed Central

Patron, Alexandra M; Hooker, Timothy S; Santavicca, Daniel F

2017-01-01

The development of methods to produce nanoscale features with tailored chemical functionalities is fundamental for applications such as nanoelectronics and sensor fabrication. The molecular-ruler process shows great utility for this purpose as it combines top-down lithography for the creation of complex architectures over large areas in conjunction with molecular self-assembly, which enables precise control over the physical and chemical properties of small local features. The molecular-ruler process, which most commonly uses mercaptoalkanoic acids and metal ions to generate metal-ligated multilayers, can be employed to produce registered nanogaps between metal features. Expansion of this methodology to include molecules with other chemical functionalities could greatly expand the overall versatility, and thus the utility, of this process. Herein, we explore the use of alkanethiol molecules as the terminating layer of metal-ligated multilayers. During this study, it was discovered that the solution deposition of alkanethiol molecules resulted in low overall surface coverage with features that varied in height. Because features with varied heights are not conducive to the production of uniform nanogaps via the molecular-ruler process, the vapor-phase deposition of alkanethiol molecules was explored. Unlike the solution-phase deposition, alkanethiol islands produced by vapor-phase deposition exhibited markedly higher surface coverages of uniform heights. To illustrate the applicability of this method, metal-ligated multilayers, both with and without an alkanethiol capping layer, were utilized to create nanogaps between Au features using the molecular-ruler process. PMID:29181290

Ultra-fast three terminal perpendicular spin-orbit torque MRAM (Presentation Recording)

NASA Astrophysics Data System (ADS)

Boulle, Olivier; Cubukcu, Murat; Hamelin, Claire; Lamard, Nathalie; Buda-Prejbeanu, Liliana; Mikuszeit, Nikolai; Garello, Kevin; Gambardella, Pietro; Langer, Juergen; Ocker, Berthold; Miron, Mihai; Gaudin, Gilles

2015-09-01

The discovery that a current flowing in a heavy metal can exert a torque on a neighboring ferromagnet has opened a new way to manipulate the magnetization at the nanoscale. This "spin orbit torque" (SOT) has been demonstrated in ultrathin magnetic multilayers with structural inversion asymmetry (SIA) and high spin orbit coupling, such as Pt/Co/AlOx multilayers. We have shown that this torque can lead to the magnetization switching of a perpendicularly magnetized nanomagnet by an in-plane current injection. The manipulation of magnetization by SOT has led to a novel concept of magnetic RAM memory, the SOT-MRAM, which combines non volatility, high speed, reliability and large endurance. These features make the SOT-MRAM a good candidate to replace SRAM for non-volatile cache memory application. We will present the proof of concept of a perpendicular SOT-MRAM cell composed of a Ta/FeCoB/MgO/FeCoB magnetic tunnel junction and demonstrate ultra-fast (down to 300 ps) deterministic bipolar magnetization switching. Macrospin and micromagnetic simulations including SOT cannot reproduce the experimental results, which suggests that additional physical mechanisms are at stacks. Our results show that SOT-MRAM is fast, reliable and low power, which is promising for non-volatile cache memory application. We will also discuss recent experiments of magnetization reversal in ultrathin multilayers Pt/Co/AlOx by very short (<200 ps) current pulses. We will show that in this material, the Dzyaloshinskii-Moryia interaction plays a key role in the reversal process.

New PVD Technologies for New Ordnance Coatings

DTIC Science & Technology

2012-04-01

characteristics using a Tantalum and a Chrome target; 4) Deposition of Ta coatings and reactive deposition of CrN; 5) Deposition parameters affecting film...Vapor Deposition (PVD); High Power Impulse Magnetron Sputtering (HIPIMS); Modulated Pulsed Power (MPP); Tantalum; Chrome ; Ta coatings; CrN; coating...The pre-production chemicals and acids are hazardous and hexavalent Cr is a known carcinogen. Significant annual expenditures are necessary to

It Takes Two: Sexual Communication Patterns and the Sexual and Relational Adjustment of Couples Coping With Provoked Vestibulodynia.

PubMed

Rancourt, Kate M; Flynn, Michelle; Bergeron, Sophie; Rosen, Natalie O

2017-03-01

Provoked vestibulodynia (PVD) is a prevalent vulvovaginal pain condition that is associated with sexual and relational consequences for women and their partners. Greater perceived quality of sexual communication has been associated with women's lower pain during intercourse and with couples' better sexual and relational well-being. Whether couples' collaborative (eg, expressing feelings or problem solving) and negative (eg, withdrawing or criticizing) sexual communication patterns (SCPs) are differentially associated with couples' adjustment to PVD is unknown. To examine associations between collaborative and negative SCPs and women's pain and the sexual and relationship adjustment of women with PVD and their partners. Women diagnosed with PVD (N = 87) and their partners completed the Sexual Communication Patterns Questionnaire and measurements of pain (women only), sexual functioning, sexual satisfaction, sexual distress, and relationship satisfaction. (i) Numerical rating scale of pain during intercourse, (ii) Female Sexual Function Index and International Index of Erectile Function, (iii) Global Measure of Sexual Satisfaction, (iv) Female Sexual Distress Scale-Revised, and (v) Couple Satisfaction Index. When women reported greater collaborative SCP, they also reported higher sexual and relationship satisfaction. When women reported greater negative SCP, they reported less relationship satisfaction and had partners who reported greater sexual distress. When partners reported greater collaborative SCP, they also reported higher relationship satisfaction and had female partners who were less sexually distressed. When partners reported higher negative SCP, they also reported less relationship satisfaction. There were no associations between SCP and women's or partners' sexual functioning or women's pain. Collaborative SCP may benefit couples' sexual and relational well-being, whereas negative SCP may impede sexual and relational adjustment to PVD. Findings provide preliminary support for the need to assess and target collaborative and negative SCPs in psychological interventions for couples affected by PVD. Rancourt KM, Flynn M, Bergeron S, Rosen NO. It Takes Two: Sexual Communication Patterns and the Sexual and Relational Adjustment of Couples Coping With Provoked Vestibulodynia. J Sex Med 2017;14:434-443. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Differences in the Biometry of the Levator Hiatus at Rest, During Contraction, and During Valsalva Maneuver Between Women With and Without Provoked Vestibulodynia Assessed by Transperineal Ultrasound Imaging.

PubMed

Thibault-Gagnon, Stéphanie; McLean, Linda; Goldfinger, Corrie; Pukall, Caroline; Chamberlain, Susan

2016-02-01

Pelvic floor muscle (PFM) involvement is suspected in the pathophysiology of provoked vestibulodynia (PVD); however, the underlying mechanisms are unclear. PFM morphology can be inferred from the biometry of the levator hiatus determined through dynamic ultrasound imaging. The aim of this study was to determine the nature of PFM involvement in women with PVD via an evaluation of the biometry of the levator hiatus at rest, upon maximal voluntary contraction (MVC) of the PFMs, and upon maximal Valsalva maneuver (MVM). Thirty-eight women with PVD and 39 asymptomatic controls were imaged using 3D transperineal ultrasound. Levator hiatal dimensions (area; left-right [LR] and anteroposterior [AP] diameters) were measured at rest, on MVC, and on MVM. Differences in hiatal dimensions and in relative changes in dimensions from rest to MVC and from rest to MVM were compared between groups using separate 1-way analyses of variance for each measure and task. Analysis of covariance models were used to investigate the impact of levator hiatal dimensions at rest on the relative changes in the levator hiatal dimensions during MVC and MVM. Levator hiatal area, LR, and AP diameters, at rest, on MVC, and on MVM were the main outcome measures. Relative changes in hiatal dimensions were assessed as the percent change in hiatal area, LR diameter, and AP diameter. In comparison with controls, women with PVD had smaller hiatal areas at rest, on MVC, and on MVM, concurrent with smaller LR diameters on MVM. Women with PVD had a significantly smaller change in hiatal area on MVM than controls, but no differences were evident on MVC. In both groups, smaller levator hiatal dimensions at rest were associated with smaller relative decreases in dimensions on MVC and larger relative increases in dimensions on MVM. In comparison to controls, women with PVD appear to have narrower levator hiatus' and less capacity to distend their hiatus on Valsalva. The state of the PFMs at rest appears to significantly influence biometric changes in the PFMs during contraction and Valsalva. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Calculation of Reflection Spectrum with Actual Layer Thickness Profile in Nacre of Akoya Pearl Oyster

NASA Astrophysics Data System (ADS)

Ozaki, R.; Yoshimoto, A.; Watanabe, G.; Kadowaki, K.; Odawara, K.

2017-11-01

Pearls have beautiful color and luster which are caused by the interference of light within a multilayer in nacre. The nacre is composed of submicron aragonite layers and nanoscale organic sheets of chitin. The value of a pearl is determined by its size, color, and luster. To improve the quality of cultured pearls, we investigate reflection properties and layer thickness profiles in pieces of nacre of Akoya pearl oyster. SEM images show us how large the thickness variation of the nacre of Akoya oyster is. We discuss the reflection properties of the pieces of nacre to connect the relation between the reflection spectra and the thickness profiles obtained by SEM observation.

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

Ioakeimidis, Apostolos; Christodoulou, Christos; Lux-Steiner, Martha

In this work we fabricate all-vacuum processed methyl ammonium lead halide perovskite by a sequence of physical vapour deposition of PbI{sub 2} and chemical vapour deposition (CVD) of CH{sub 3}NH{sub 3}I under a static atmosphere. We demonstrate that for higher deposition rate the (001) planes of PbI{sub 2} film show a higher degree of alignment parallel to the sample's surface. From X-ray diffraction data of the resulted perovskite film we derive that the intercalation rate of CH{sub 3}NH{sub 3}I is fostered for PbI{sub 2} films with higher degree of (001) planes alignment. The stoichiometry of the produced perovskite film ismore » also studied by Hard X-ray photoelectron spectroscopy measurements. Complete all-vacuum perovskite solar cells were fabricated on glass/ITO substrates coated by an ultra-thin (5 nm) Zn-phthalocyanine film as hole selective layer. A dependence of residual PbI{sub 2} on the solar cells performance is displayed, while photovoltaic devices with efficiency up to η=11.6% were achieved. - Graphical abstract: A two-step PVD/CVD processed perovskite film with the CVD intercalation rate of CH{sub 3}NCH{sub 3} molecules been fostered by increasing the PVD rate of PbI{sub 2} and prolonging the CVD time. - Highlights: • A simple PVD/CVD process for perovskite film production. • Increased PVD rate yields better alignment of the PbI{sub 2} (001) crystallite planes. • CH{sub 3}NH{sub 3}I intercalation process fostered by increased PbI{sub 2} PVD rate. • Stoichiometric CH{sub 3}NH{sub 3}PbI{sub 3} suitable as absorber in photovoltaic applications • Reduced PbI{sub 2} residue at the bottom of CH{sub 3}NH{sub 3}PbI{sub 3} improves device performance.« less

C-Ni-Pd and CNT-Ni-Pd film's molecular and crystalline structure investigations by FTIR spectroscopy and XRD diffraction

NASA Astrophysics Data System (ADS)

Stepińska, Izabela; Czerwosz, ElŻbieta; Diduszko, Ryszard; Kozłowski, Mirosław; Wronka, Halina

2017-08-01

In this work molecular and crystalline structure of new type of nanocomposite films were investigated. These films compose of CNT decorated with palladium nanograins. They were prepared on a base of C-Ni films modified in CVD process. C-Ni nanocomposite films were obtained by PVD process and their modification by CVD leads to a growth of CNT film. CNTs-Ni or C-Ni films were treated with additional PVD process with palladium. Nickel and palladium acetate and fulleren C60 are precursors of films in PVD process. FTIR spectroscopy was used to studied the molecular structure of film in every stage of preparation . The crystalline structure of these films was studied by X-ray diffraction. SEM (scanning electron microscopy) was applied to investigate film's surface topography.

The Impact of a Woman's Dyspareunia and Its Treatment on Her Intimate Partner: A Qualitative Analysis.

PubMed

Sadownik, Leslie A; Smith, Kelly B; Hui, Amber; Brotto, Lori A

2017-08-18

This study explored the experiences of male partners of women with dyspareunia, secondary to provoked vestibulodynia (PVD), who participated in the Multidisciplinary Vulvodynia Program (MVP). Participants were 16 men between 22 and 45 years of age. Data were collected with semi-structured interviews and analyzed for themes. Men were interviewed about (a) the impact of the woman's PVD on themselves; and (b) the impact of the MVP on themselves. Participants experienced negative psychological effects (e.g., guilt) in addition to activating emotions (e.g., frustration). They reported diminished quantity and quality of sex. In the relationship, PVD caused strain, communication challenges, and possibilities for growth. The benefits, perceived by the partner, of the women participating in the treatment program included improvements in knowledge, communication, and psychological and sexual health.

PVD Silicon Carbide as a Thin Film Packaging Technology for Antennas on LCP Substrates for Harsh Environments

NASA Technical Reports Server (NTRS)

Scardelletti, Maximilian C.; Stanton, John W.; Ponchak, George E.; Jordan, Jennifer L.; Zorman, Christian A.

2010-01-01

This paper describes an effort to develop a thin film packaging technology for microfabricated planar antennas on polymeric substrates based on silicon carbide (SiC) films deposited by physical vapor deposition (PVD). The antennas are coplanar waveguide fed dual frequency folded slot antennas fabricated on liquid crystal polymer (LCP) substrates. The PVD SiC thin films were deposited directly onto the antennas by RF sputtering at room temperature at a chamber pressure of 30 mTorr and a power level of 300 W. The SiC film thickness is 450 nm. The return loss and radiation patterns were measured before and after the SiC-coated antennas were submerged into perchloric acid for 1 hour. No degradation in RF performance or physical integrity of the antenna was observed.

Layer-by-layer self-assembly in the development of electrochemical energy conversion and storage devices from fuel cells to supercapacitors.

PubMed

Xiang, Yan; Lu, Shanfu; Jiang, San Ping

2012-11-07

As one of the most effective synthesis tools, layer-by-layer (LbL) self-assembly technology can provide a strong non-covalent integration and accurate assembly between homo- or hetero-phase compounds or oppositely charged polyelectrolytes, resulting in highly-ordered nanoscale structures or patterns with excellent functionalities and activities. It has been widely used in the developments of novel materials and nanostructures or patterns from nanotechnologies to medical fields. However, the application of LbL self-assembly in the development of highly efficient electrocatalysts, specific functionalized membranes for proton exchange membrane fuel cells (PEMFCs) and electrode materials for supercapacitors is a relatively new phenomenon. In this review, the application of LbL self-assembly in the development and synthesis of key materials of PEMFCs including polyelectrolyte multilayered proton-exchange membranes, methanol-blocking Nafion membranes, highly uniform and efficient Pt-based electrocatalysts, self-assembled polyelectrolyte functionalized carbon nanotubes (CNTs) and graphenes will be reviewed. The application of LbL self-assembly for the development of multilayer nanostructured materials for use in electrochemical supercapacitors will also be reviewed and discussed (250 references).

Modelling of particle-laden flow inside nanomaterials.

PubMed

Chan, Yue; Wylie, Jonathan J; Xia, Liang; Ren, Yong; Chen, Yung-Tsang

2016-08-01

In this paper, we demonstrate the usage of the Nernst-Planck equation in conjunction with mean-field theory to investigate particle-laden flow inside nanomaterials. Most theoretical studies in molecular encapsulation at the nanoscale do not take into account any macroscopic flow fields that are crucial in squeezing molecules into nanostructures. Here, a multi-scale idea is used to address this issue. The macroscopic transport of gas is described by the Nernst-Planck equation, whereas molecular interactions between gases and between the gas and the host material are described using a combination of molecular dynamics simulation and mean-field theory. In particular, we investigate flow-driven hydrogen storage inside doubly layered graphene sheets and graphene-oxide frameworks (GOFs). At room temperature and with slow velocity fields, we find that a single molecular layer is formed almost instantaneously on the inner surface of the graphene sheets, while molecular ligands between GOFs induce multi-layers. For higher velocities, multi-layers are also formed between graphene. For even larger velocities, the cavity of graphene is filled entirely with hydrogen, whereas for GOFs there exist two voids inside each periodic unit. The flow-driven hydrogen storage inside GOFs with various ligand densities is also investigated.

Modelling of particle-laden flow inside nanomaterials

NASA Astrophysics Data System (ADS)

Chan, Yue; Wylie, Jonathan J.; Xia, Liang; Ren, Yong; Chen, Yung-Tsang

2016-08-01

In this paper, we demonstrate the usage of the Nernst-Planck equation in conjunction with mean-field theory to investigate particle-laden flow inside nanomaterials. Most theoretical studies in molecular encapsulation at the nanoscale do not take into account any macroscopic flow fields that are crucial in squeezing molecules into nanostructures. Here, a multi-scale idea is used to address this issue. The macroscopic transport of gas is described by the Nernst-Planck equation, whereas molecular interactions between gases and between the gas and the host material are described using a combination of molecular dynamics simulation and mean-field theory. In particular, we investigate flow-driven hydrogen storage inside doubly layered graphene sheets and graphene-oxide frameworks (GOFs). At room temperature and with slow velocity fields, we find that a single molecular layer is formed almost instantaneously on the inner surface of the graphene sheets, while molecular ligands between GOFs induce multi-layers. For higher velocities, multi-layers are also formed between graphene. For even larger velocities, the cavity of graphene is filled entirely with hydrogen, whereas for GOFs there exist two voids inside each periodic unit. The flow-driven hydrogen storage inside GOFs with various ligand densities is also investigated.

Surface self-organization in multilayer film coatings

NASA Astrophysics Data System (ADS)

Shuvalov, Gleb M.; Kostyrko, Sergey A.

2017-12-01

It is a recognized fact that during film deposition and subsequent thermal processing the film surface evolves into an undulating profile. Surface roughness affects many important aspects in the engineering application of thin film materials such as wetting, heat transfer, mechanical, electromagnetic and optical properties. To accurately control the morphological surface modifications at the micro- and nanoscale and improve manufacturing techniques, we design a mathematical model of the surface self-organization process in multilayer film materials. In this paper, we consider a solid film coating with an arbitrary number of layers under plane strain conditions. The film surface has a small initial perturbation described by a periodic function. It is assumed that the evolution of the surface relief is governed by surface and volume diffusion. Based on Gibbs thermodynamics and linear theory of elasticity, we present a procedure for constructing a governing equation that gives the amplitude change of the surface perturbation with time. A parametric study of the evolution equation leads to the definition of a critical undulation wavelength that stabilizes the surface. As a numerical result, the influence of geometrical and physical parameters on the morphological stability of an isotropic two-layered film coating is analyzed.

Unpolarized resonance grating reflectors with 44% fractional bandwidth.

PubMed

Niraula, Manoj; Magnusson, Robert

2016-06-01

There is immense scientific interest in the properties of resonant thin films embroidered with periodic nanoscale features. This device class possesses considerable innovation potential. Accordingly, we report unpolarized broadband reflectors enabled by a serial arrangement of a pair of polarized subwavelength gratings. Optimized with numerical methods, our elemental gratings consist of a partially etched crystalline-silicon film on a quartz substrate. The resulting reflectors exhibit extremely wide spectral reflection bands in one polarization. By arranging two such reflectors sequentially with orthogonal periodicities, there results an unpolarized spectral band that exceeds those of the individual polarized bands. In the experiments reported herein, we achieve zero-order reflectance exceeding 97% under unpolarized light incidence over a 500 nm wide wavelength band. This wideband represents a ∼44% fractional band in the near infrared. Moreover, the resonant unpolarized broadband accommodates an ultra-high reflection band spanning ∼85  nm and exceeding 99.9% in efficiency. The elemental polarization-sensitive reflectors based on one-dimensional (1D) resonant gratings have a simple design and robust performance, and are straightforward to fabricate. Hence, this technology is a promising alternative to traditional multilayer thin-film reflectors, especially at longer wavelengths of light where multilayer deposition may be infeasible or impractical.

Nanostructured multilayer thin films of multiwalled carbon nanotubes/gold nanoparticles/glutathione for the electrochemical detection of dopamine

NASA Astrophysics Data System (ADS)

Detsri, Ekarat; Rujipornsakul, Sirilak; Treetasayoot, Tanapong; Siriwattanamethanon, Pawarit

2016-10-01

In the present study, multiwalled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs), and glutathione (GSH) were used to fabricate multilayer nanoscale thin films. The composite thin films were fabricated by layer-by-layer technique as the films were constructed by the alternate deposition of cationic and anionic polyelectrolytes. The MWCNTs were modified via a noncovalent surface modification method using poly(diallydimethylammonium chloride) to form a cationic polyelectrolyte. An anionic polyelectrolyte was prepared by the chemical reduction of HAuCl4 using sodium citrate as both the stabilizing and reducing agent to form anionic AuNPs. GSH was used as an electrocatalyst toward the electro-oxidation of dopamine. The constructed composite electrode exhibits excellent electrocatalytic activity toward dopamine with a short response time and a wide linear range from 1 to 100 μmol/L. The limits of detection and quantitation of dopamine are (0.316 ± 0.081) μmol/L and (1.054 ± 0.081) μmol/L, respectively. The method is satisfactorily applied for the determination of dopamine in plasma and urine samples to obtain the recovery in the range from 97.90% to 105.00%.

Many-body Effect, Carrier Mobility, and Device Performance of Hexagonal Arsenene and Antimonene

NASA Astrophysics Data System (ADS)

Wang, Yangyang; Ye, Meng; Quhe, Ruge; Huang, Pu; Lu, Jing

Monolayer (ML) arsenene and antimonene, as new members of group V-enes, have attracted great interest. Experimentally, multilayer arsenene/antimonene nanoribbons have been fabricated on an InAs/InSb substrate. ML and multilayer antimonene have been isolated by mechanical exfoliation and liquid-phase exfoliation. More importantly, they are highly stable under ambient condition. Together with their wide band gaps predicted by the HSE theory, arsenene and antimonene are very attractive for nanoscale optoelectronic and electronic devices. We investigate the many-body effect and device performance of ML hexagonal arsenene and antimonene using ab initio GW, GW plus Bethe-Salpeter equation and nonequilibrium Green's function approach. The quasi-particle and optical band gaps are calculated in ML arsenene and antimonene for the first time. Low (21/66 cm2/V .s for electron/hole) and moderate carrier mobilities (150/510 cm2/V .s for electron/hole) are obtained, for arsenene and antimonene, respectively. Quantum transport simulation reveals that the performance limits of sub-10 nm ML arsenene and antimonene FETs can satisfy both low power and high performance requirements of the ITRS target in the next decade. National Natural Science Foundation of China (No. 11274016/11474012/11674005/11274233).

Solution Coating of Pharmaceutical Nanothin Films and Multilayer Nanocomposites with Controlled Morphology and Polymorphism.

PubMed

Horstman, Elizabeth M; Kafle, Prapti; Zhang, Fengjiao; Zhang, Yifu; Kenis, Paul J A; Diao, Ying

2018-03-28

Nanosizing is rapidly emerging as an alternative approach to enhance solubility and thus the bioavailability of poorly aqueous soluble active pharmaceutical ingredients (APIs). Although numerous techniques have been developed to perform nanosizing of API crystals, precise control and modulation of their size in an energy and material efficient manner remains challenging. In this study, we present meniscus-guided solution coating as a new technique to produce pharmaceutical thin films of nanoscale thickness with controlled morphology. We demonstrate control of aspirin film thickness over more than 2 orders of magnitude, from 30 nm to 1.5 μm. By varying simple process parameters such as the coating speed and the solution concentration, the aspirin film morphology can also be modulated by accessing different coating regimes, namely the evaporation regime and the Landau-Levich regime. Using ellipticine-a poorly water-soluble anticancer drug-as another model compound, we discovered a new polymorph kinetically trapped during solution coating. Furthermore, the polymorphic outcome can be controlled by varying coating conditions. We further performed layer-by-layer coating of multilayer nanocomposites, with alternating thin films of ellipticine and a biocompatible polymer, which demonstrate the potential of additive manufacturing of multidrug-personalized dosage forms using this approach.

Nonlinear geometric scaling of coercivity in a three-dimensional nanoscale analog of spin ice

NASA Astrophysics Data System (ADS)

Shishkin, I. S.; Mistonov, A. A.; Dubitskiy, I. S.; Grigoryeva, N. A.; Menzel, D.; Grigoriev, S. V.

2016-08-01

Magnetization hysteresis loops of a three-dimensional nanoscale analog of spin ice based on the nickel inverse opal-like structure (IOLS) have been studied at room temperature. The samples are produced by filling nickel into the voids of artificial opal-like films. The spin ice behavior is induced by tetrahedral elements within the IOLS, which have the same arrangement of magnetic moments as a spin ice. The thickness of the films vary from a two-dimensional, i.e., single-layered, antidot array to a three-dimensional, i.e., multilayered, structure. The coercive force, the saturation, and the irreversibility field have been measured in dependence of the thickness of the IOLS for in-plane and out-of-plane applied fields. The irreversibility and saturation fields change abruptly from the antidot array to the three-dimensional IOLS and remain constant upon further increase of the number of layers n . The coercive force Hc seems to increase logarithmically with increasing n as Hc=Hc 0+α ln(n +1 ) . The logarithmic law implies the avalanchelike remagnetization of anisotropic structural elements connecting tetrahedral and cubic nodes in the IOLS. We conclude that the "ice rule" is the base of mechanism regulating this process.

Extreme Mechanical Behavior of Nacre-Mimetic Graphene-Oxide and Silk Nanocomposites.

PubMed

Xie, Wanting; Tadepalli, Sirimuvva; Park, Sang Hyun; Kazemi-Moridani, Amir; Jiang, Qisheng; Singamaneni, Srikanth; Lee, Jae-Hwang

2018-02-14

Biological materials have the ability to withstand extreme mechanical forces due to their unique multilevel hierarchical structure. Here, we fabricated a nacre-mimetic nanocomposite comprised of silk fibroin and graphene oxide that exhibits hybridized dynamic responses arising from alternating high-contrast mechanical properties of the components at the nanoscale. Dynamic mechanical behavior of these nanocomposites is assessed through a microscale ballistic characterization using a 7.6 μm diameter silica sphere moving at a speed of approximately 400 m/s. The volume fraction of graphene oxide in these composites is systematically varied from 0 to 32 vol % to quantify the dynamic effects correlating with the structural morphologies of the graphene oxide flakes. Specific penetration energy of the films rapidly increases as the distribution of graphene oxide flakes evolves from noninteracting, isolated sheets to a partially overlapping continuous sheet. The specific penetration energy of the nanocomposite at the highest graphene oxide content tested here is found to be significantly higher than that of Kevlar fabrics and close to that of pure multilayer graphene. This study evidently demonstrates that the morphologies of nanoscale constituents and their interactions are critical to realize scalable high-performance nanocomposites using typical nanomaterial constituents having finite dimensions.

Integrating SIMNET into Heavy Task Force Tactical Training

DTIC Science & Technology

1994-10-01

the overlays will allow the battlemaster time to input them for display on the Plan View Display ( PVD ) for use in AARs. The time schedule must also...reconnaissance for both friendly and enemy forces to occupy. The stealth station, in conjunction with the Plan View Display ( PVD ), can be used to...was moved to another assembly area for armor crewman and Nuclear, Biological, and Chemical (NBC) skills testing. The battalion observer tested 25% to

Defense Small Business Innovation Research Program (SBIR). Volume 1. Army Abstracts of Phase 1 Awards 1987.

DTIC Science & Technology

1988-04-01

TECHNOLOGY TO PROTECT LAMINATED FIBERGLASS REIN- FORCES STRUCTURES FROM CHEMICAL AGENTS AND DECONTAMINANTS . FLAME0 RETARDENCY, ADHESION, ABRASION RESISTANCE...OFFICE: BRDC- PVD ALTHOUGH THERE ARE NO INTRINSIC CONFLICTS FOR THE SAME MATERIAL SYSTEMS TO ACHIEVE BOTH THE RADAR ABSORPTION AND THERMAL SUPPRESSION...VEHICLE TOPIC# 135 OFFICE: BRDC- PVD THE OBJECTIVE OF THE PHASE I RESEARCH AND DEVELOPMENT PROPOSED HEREIN IS TO DETERMINE WHICH MAJOR COMPONENTS OF THE

Quantitative near-infrared spectroscopy on patients with peripheral vascular disease

NASA Astrophysics Data System (ADS)

Franceschini, Maria-Angela; Fantini, Sergio; Palumbo, Renato; Pasqualini, Leonella; Vaudo, Gaetano; Franceschini, Edoardo; Gratton, Enrico; Palumbo, Barbara; Innocente, Salvatore; Mannarino, Elmo

1998-01-01

We have used near-infrared spectroscopy to measure the hemoglobin saturation at rest and during exercise on patients affected by peripheral vascular disease (PVD). The instrument used in our study is a frequency-domain tissue oximeter which employs intensity modulated (110 MHz) laser diodes. We examined 9 subjects, 3 of which were controls and 6 were patients affected by stage II PVD. The optical probe was located on the calf muscle of the subjects. The measurement protocol consisted of: (1) baseline (approximately 5 min); (2) stationary bicycle exercise (approximately 5 min); (3) recovery (approximately 15 min). The change in hemoglobin saturation during exercise ((Delta) Y) and the recovery time after exercise (trec) were significantly greater in the PVD patients ((Delta) Y equals -21 +/- 3%, trec equals 5.9 +/- 3.8 min) than in the control subjects ((Delta) Y equals 2 +/- 3%, trec equals 0.6 +/- 0.1 min).

Pitting corrosion resistance of nickel-titanium rotary instruments with different surface treatments in seventeen percent ethylenediaminetetraacetic Acid and sodium chloride solutions.

PubMed

Bonaccorso, Antonio; Tripi, Teresa Roberta; Rondelli, Gianni; Condorelli, Guglielmo Guido; Cantatore, Giuseppe; Schäfer, Edgar

2008-02-01

This study evaluated the pitting corrosion resistance of nickel-titanium (NiTi) rotary instruments with different surface treatments in 17% ethylenediaminetetraacetic acid (EDTA) and NaCl solutions. Electropolished RaCe instruments were allocated to group A, non-electropolished RaCe instruments to group B, and physical vapor deposition (PVD)-coated Alpha files to group C (10 instruments per group). Electrochemical measurements were carried out by using a potentiostat for galvanic current measurements. On the basis of electrochemical tests, no localized corrosion problems are to be expected in EDTA. In NaCl, pitting potential occurred at higher values for the electropolished and PVD instruments, indicating an increased corrosion resistance. There appears to be a risk of corrosion for NiTi instruments without surface treatments in contact with NaCl. NiTi files with PVD and electropolishing surface treatments showed an increase corrosion resistance.

Separator for lithium-sulfur battery based on polymer blend membrane

NASA Astrophysics Data System (ADS)

Freitag, Anne; Stamm, Manfred; Ionov, Leonid

2017-09-01

In this work we report a novel way of reducing the polysulfide shuttle in lithium-sulfur batteries by a new separator material. Polyvinylsulfate potassium salt (PVSK) as polymeric additive is introduced into a polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) matrix membrane to improve the battery performance. PVSK is expected to lower the polysulfide mobility due to interaction with the sulfonic group. PVdF-HFP/PVSK blend membranes are prepared and an UV/Vis polysulfide diffusion test clearly demonstrates the positive effect of PVSK. Electrochemical testing reveals a significant improvement of cycling stability up to more than 200 cycles. In addition, the effect of separator porosity to the polysulfide shuttle is investigated with PVdF-HFP membranes of different porosity. A simple polysulfide diffusion test and potentiostatic charge/discharge cycling clearly demonstrate that low separator porosity is favorable in a lithium-sulfur cell.

Passivation effect on optical and electrical properties of molecular beam epitaxy-grown HgCdTe/CdTe/Si layers

NASA Astrophysics Data System (ADS)

Kiran, Rajni; Mallick, Shubhrangshu; Hahn, Suk-Ryong; Lee, T. S.; Sivananthan, Sivalingam; Ghosh, Siddhartha; Wijewarnasuriya, P. S.

2006-06-01

The effects of passivation with two different passivants, ZnS and CdTe, and two different passivation techniques, physical vapor deposition (PVD) and molecular beam epitaxy (MBE), were quantified in terms of the minority carrier lifetime and extracted surface recombination velocity on both MBE-grown medium-wavelength ir (MWIR) and long-wavelength ir HgCdTe samples. A gradual increment of the minority carrier lifetime was reported as the passivation technique was changed from PVD ZnS to PVD CdTe, and finally to MBE CdTe, especially at low temperatures. A corresponding reduction in the extracted surface recombination velocity in the same order was also reported for the first time. Initial data on the 1/ f noise values of as-grown MWIR samples showed a reduction of two orders of noise power after 1200-Å ZnS deposition.

Pd-Ni-MWCNT nanocomposite thin films: preparation and structure

NASA Astrophysics Data System (ADS)

Kozłowski, Mirosław; Czerwosz, ElŻbieta; Sobczak, Kamil

2017-08-01

The properties of nanocomposite palladium-nickel-multi-walled (Pd-Ni-MWCNT) films deposited on aluminum oxide (Al2O3) substrate have been prepared and investigated. These films were obtained by 3 step process consisted of PVD/CVD/PVD methods. The morphology and structure of the obtained films were characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques at various stages of the film formation. EDX spectrometer was used to measurements of elements segregation in the obtained film. TEM and STEM (Scanning Transmission Electron Microscopy) observations showed MWCNTs decorated with palladium nanoparticles in the film obtained in the last step of film formation (final PVD process). The average size of the palladium nanoparticles observed both on MWCNTs and carbonaceous matrix does not exceed 5 nm. The research was conducted on the use of the obtained films as potential sensors of gases (e.g. H2, NH3, CO2) and bio-sensors or optical sensors.

Interaction of Ester-Functionalized Ionic Liquids with Atomically-Defined Cobalt Oxides Surfaces: Adsorption, Reaction and Thermal Stability.

PubMed

Xu, Tao; Waehler, Tobias; Vecchietti, Julia; Bonivardi, Adrian; Bauer, Tanja; Schwegler, Johannes; Schulz, Peter S; Wasserscheid, Peter; Libuda, Joerg

2017-12-06

Hybrid materials consisting of ionic liquid (ILs) films on supported oxides hold a great potential for applications in electronic and energy materials. In this work, we have performed surface science model studies scrutinizing the interaction of ester-functionalized ILs with atomically defined Co 3 O 4 (111) and CoO(100) surfaces. Both supports are prepared under ultra-high vacuum (UHV) conditions in form of thin films on Ir(100) single crystals. Subsequently, thin films of three ILs, 3-butyl-1-methyl imidazolium bis(trifluoromethyl-sulfonyl) imide ([BMIM][NTf 2 ]), 3-(4-methoxyl-4-oxobutyl)-1-methylimidazolium bis(trifluoromethyl-sulfonyl) imide ([MBMIM][NTf 2 ]), and 3-(4-isopropoxy-4-oxobutyl)-1-methylimidazolium bis(trifluoromethyl-sulfonyl) imide ([IPBMIM][NTf 2 ]), were deposited on these surfaces by physical vapor deposition (PVD). Time-resolved and temperature-programmed infrared reflection absorption spectroscopy (TR-IRAS, TP-IRAS) were applied to monitor in situ the adsorption, film growth, and thermally induced desorption. By TP-IRAS, we determined the multilayer desorption temperature of [BMIM][NTf 2 ] (360±5 K), [MBMIM][NTf 2 ] (380 K) and [IPBMIM][NTf 2 ] (380 K). Upon deposition below the multilayer desorption temperature, all three ILs physisorb on both cobalt oxide surfaces. However, strong orientation effects are observed in the first monolayer, where the [NTf 2 ] - ion interacts with the surface through the SO 2 groups and the CF 3 groups point towards the vacuum. For the two functionalized ILs, the [MBMIM] + and [IPBMIM] + interact with the surface Co 2+ ions of both surfaces via the CO group of their ester function. A very different behavior is found, if the ILs are deposited above the multilayer desorption temperature (400 K). While for [BMIM][NTf 2 ] and [MBMIM][NTf 2 ] a molecularly adsorbed monolayer film is formed, [IPBMIM][NTf 2 ] undergoes a chemical transformation on the CoO(100) surface. Here, the ester group is cleaved and the cation is chemically linked to the surface by formation of a surface carboxylate. The IL-derived species in the monolayer desorb at temperatures around 500 to 550 K. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Differential protein partitioning within the herpesvirus tegument and envelope underlies a complex and variable virion architecture

PubMed Central

Bohannon, Kevin Patrick; Jun, Yonggun; Gross, Steven P.; Smith, Gregory Allan

2013-01-01

The herpesvirus virion is a multilayered structure consisting of a DNA-filled capsid, tegument, and envelope. Detailed reconstructions of the capsid are possible based on its icosahedral symmetry, but the surrounding tegument and envelope layers lack regular architecture. To circumvent limitations of symmetry-based ultrastructural reconstruction methods, a fluorescence approach was developed using single-particle imaging combined with displacement measurements at nanoscale resolution. An analysis of 11 tegument and envelope proteins defined the composition and plasticity of symmetric and asymmetric elements of the virion architecture. The resulting virion protein map ascribes molecular composition to density profiles previously acquired by traditional ultrastructural methods, and provides a way forward to examine the dynamics of the virion architecture during infection. PMID:23569236

Surface modification of Ti alloy by electro-explosive alloying and electron-beam treatment

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

Gromov, Victor, E-mail: gromov@physics.sibsiu.ru; Kobzareva, Tatiana, E-mail: kobzarevatanya@mail.ru; Budovskikh, Evgeniy, E-mail: budovskih-ea@physics.sibsiu.ru

2016-01-15

By methods of modern physical metallurgy the analysis of structure phase states of titanium alloy VT6 is carried out after electric explosion alloying with boron carbide and subsequent irradiation by pulsed electron beam. The formation of an electro-explosive alloying zone of a thickness up to 50 µm, having a gradient structure, characterized by decrease in the concentration of carbon and boron with increasing distance to the treatable surface has been revealed. Subsequent electron-beam treatment of alloying zone leads to smoothing of the alloying area surface and is accompanied by the multilayer structure formation at the depth of 30 µm withmore » alternating layers with different alloying degrees having the structure of submicro - and nanoscale level.« less

Shape-Morphing Nanocomposite Origami

PubMed Central

2015-01-01

Nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations. This property is essential, for example, for new energy-saving technologies, efficient collection of solar radiation, and thermal management. Here we report a similar shape-morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an LBL carbon nanotube (CNT) composite. The out-of-plane deflection can be precisely controlled, as predicted by theoretical analysis. We also demonstrate a controlled and stimuli-responsive twisting motion on a spiral-shaped LBL nanocomposite. By mimicking the motions achieved in nature, this method offers new opportunities for the design and fabrication of functional stimuli-responsive shape-morphing nanoscale and microscale structures for a variety of applications. PMID:24689908

The image-forming mirror in the eye of the scallop

NASA Astrophysics Data System (ADS)

Palmer, Benjamin A.; Taylor, Gavin J.; Brumfeld, Vlad; Gur, Dvir; Shemesh, Michal; Elad, Nadav; Osherov, Aya; Oron, Dan; Weiner, Steve; Addadi, Lia

2017-12-01

Scallops possess a visual system comprising up to 200 eyes, each containing a concave mirror rather than a lens to focus light. The hierarchical organization of the multilayered mirror is controlled for image formation, from the component guanine crystals at the nanoscale to the complex three-dimensional morphology at the millimeter level. The layered structure of the mirror is tuned to reflect the wavelengths of light penetrating the scallop’s habitat and is tiled with a mosaic of square guanine crystals, which reduces optical aberrations. The mirror forms images on a double-layered retina used for separately imaging the peripheral and central fields of view. The tiled, off-axis mirror of the scallop eye bears a striking resemblance to the segmented mirrors of reflecting telescopes.

Differential protein partitioning within the herpesvirus tegument and envelope underlies a complex and variable virion architecture.

PubMed

Bohannon, Kevin Patrick; Jun, Yonggun; Gross, Steven P; Smith, Gregory Allan

2013-04-23

The herpesvirus virion is a multilayered structure consisting of a DNA-filled capsid, tegument, and envelope. Detailed reconstructions of the capsid are possible based on its icosahedral symmetry, but the surrounding tegument and envelope layers lack regular architecture. To circumvent limitations of symmetry-based ultrastructural reconstruction methods, a fluorescence approach was developed using single-particle imaging combined with displacement measurements at nanoscale resolution. An analysis of 11 tegument and envelope proteins defined the composition and plasticity of symmetric and asymmetric elements of the virion architecture. The resulting virion protein map ascribes molecular composition to density profiles previously acquired by traditional ultrastructural methods, and provides a way forward to examine the dynamics of the virion architecture during infection.

Microstructural Effects and Properties of Non-line-of-Sight Coating Processing via Plasma Spray-Physical Vapor Deposition

NASA Astrophysics Data System (ADS)

Harder, Bryan J.; Zhu, Dongming; Schmitt, Michael P.; Wolfe, Douglas E.

2017-08-01

Plasma spray-physical vapor deposition (PS-PVD) is a unique processing method that bridges the gap between conventional thermal spray and vapor phase methods, and enables highly tailorable coatings composed of a variety of materials in thin, dense layers or columnar microstructures with modification of the processing conditions. The strengths of this processing technique are material and microstructural flexibility, deposition speed, and potential for non-line-of-sight (NLOS) capability by vaporization of the feedstock material. The NLOS capability of PS-PVD is investigated here using yttria-stabilized zirconia and gadolinium zirconate, which are materials of interest for turbine engine applications. PS-PVD coatings were applied to static cylindrical substrates approximately 6-19 mm in diameter to study the coating morphology as a function of angle. In addition, coatings were deposited on flat substrates under various impingement configurations. Impingement angle had significant effects on the deposition mode, and microscopy of coatings indicated that there was a shift in the deposition mode at approximately 90° from incidence on the cylindrical samples, which may indicate the onset of more turbulent flow and PVD-like growth. Coatings deposited at non-perpendicular angles exhibited a higher density and nearly a 2× improvement in erosion performance when compared to coatings deposited with the torch normal to the surface.

Processing of sputter targets using current activated pressure assisted densification

NASA Astrophysics Data System (ADS)

Chaney, Neil Russell

Thin Film deposition is a process that has been around since the beginning of the twentieth century and has become an integral part of the microfabrication and nanofabrication industries. Sputter deposition is a method of physical vapor deposition (PVD) in which a target is bombarded with ions and atoms are ejected and deposited as a thin film on a substrate. Despite extensive research on the direct process of sputtering thin films from targets to substrates, not much work has been done on studying the effect of processing on the microstructure of a target. In the first part of this work, the development of a PVD chamber is explored along with a few modifications and improvements developed along the way. A multiple process PVD chamber was equipped with three different types of PVD processes: sputtering, evaporation, and electron-beam deposition. In the second part of this work, the effect of processing of sputter targets on deposited films is explored. Multiple targets of Copper and yttria stabilized zirconia were produced using CAPAD. The effect of the processing on the microstructure of the targets was determined. The targets were then sputtered into films to study the effects of the target grain size on their properties. The effect of power and pressure were also measured. Increased power led to increased deposition rates while higher vacuum caused deposition rates to decrease.

Enhancing the oxidation resistance of graphite by applying an SiC coat with crack healing at an elevated temperature

NASA Astrophysics Data System (ADS)

Park, Jae-Won; Kim, Eung-Seon; Kim, Jae-Un; Kim, Yootaek; Windes, William E.

2016-08-01

The potential of reducing the oxidation of the supporting graphite components during normal and/or accident conditions in the Very High Temperature Reactor (VHTR) design has been studied. In this work efforts have been made to slow the oxidation process of the graphite with a thin SiC coating (∼ 10 μm). Upon heating at ≥ 1173 K in air, the spallations and cracks were formed in the dense columnar structured SiC coating layer grown on the graphite with a functionally gradient electron beam physical vapor deposition (EB-PVD. In accordance with the formations of these defects, the sample was vigorously oxidized, leaving only the SiC coating layer. Then, efforts were made to heal the surface defects using additional EB-PVD with ion beam bombardment and chemical vapor deposition (CVD). The EB-PVD did not effectively heal the cracks. But, the CVD was more appropriate for crack healing, likely due to its excellent crack line filling capability with a high density and high aspect ratio. It took ∼ 34 min for the 20% weight loss of the CVD crack healed sample in the oxidation test with annealing at 1173 K, while it took ∼ 8 min for the EB-PVD coated sample, which means it took ∼4 times longer at 1173 K for the same weight reduction in this experimental set-up.

Influence of the Vitreoretinal Interface on the Treatment with Anti-VEGF for Exudative Age-Related Macular Degeneration.

PubMed

Gil, Pedro; Gil, João; Oliveira, Nuno; Laíns, Inês; Camilo, Eduardo Nery Rossi; Fonseca, Cristina; Raimundo, Miguel; Cachulo, Maria da Luz; Silva, Rufino

2018-05-07

To investigate the influence of the vitreoretinal interface on the outcomes of different ranibizumab regimens for exudative age-related macular degeneration. We conducted a retrospective subanalysis of 2 prospective clinical trials. Patients were treated with ranibizumab for 12 months according to 3 different regimens: pro-re-nata (PRN), treat and extend (T&E), and monthly. Vitreoretinal interface was assessed for absence (group ON) or presence (group OFF) of posterior vitreous detachment (PVD). We included 64 eyes from 64 patients. Visual improvement was poorer for group ON (0.3 ± 10.7 letters) than for group OFF (9.2 ± 13.3; p = 0.007). A significant difference in letters of improvement between groups was observed in the PRN cohort (ON: -5.0 ± 12.9; OFF: 11.4 ± 11.9; p = 0.003), but not in the cohorts with monthly (ON: 5.7 ± 7.8; OFF: 7.9 ± 15.2; p = 0.735) or T&E (ON: 4.3 ± 4.3; OFF: 7.8 ± 11.1; p = 0.424) treatment. The negative impact of absence of PVD is regimen dependent, with monthly dosing providing similar outcomes to PVD patients. In the absence of PVD (group ON), PRN should be avoided, and T&E might be an alternative. © 2018 S. Karger AG, Basel.

Graphite//LiNi0.5 Mn1.5 O4 Cells Based on Environmentally Friendly Made-in-Water Electrodes.

PubMed

De Giorgio, Francesca; Laszczynski, Nina; von Zamory, Jan; Mastragostino, Marina; Arbizzani, Catia; Passerini, Stefano

2017-01-20

The performance of graphite//LiNi 0.5 Mn 1.5 O 4 (LNMO) cells, both electrodes of which are made using water-soluble sodium carboxymethyl cellulose (CMC) binder, is reported for the first time. The full cell performed outstandingly over 400 cycles in the conventional electrolyte ethylene carbonate/dimethyl carbonate-1 m LiPF 6 , and the delivered specific energy at the 100th, 200th, 300th, and 400th cycle corresponded to 82, 78, 73, and 66 %, respectively, of the initial energy value of 259 Wh kg -1 (referring to the sum of the two electrode-composite weights). The good stability of high-voltage, LNMO-CMC-based electrodes upon long-term cycling is discussed and the results are compared to those of LNMO-composite electrodes with polyvinylidene fluoride (PVdF). LNMO-CMC electrodes outperformed those with PVdF binder, displaying a capacity retention of 83 % compared to 62 % for the PVdF-based electrodes after 400 cycles at 1 C. CMC promotes a more compact and stable electrode surface than PVdF; undesired interfacial reactions at high operating voltages are mitigated, and the thickness of the passivation layer on the LNMO surface is reduced, thereby enhancing its cycling stability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Acceptance of vulvovaginal pain in women with provoked vestibulodynia and their partners: associations with pain, psychological, and sexual adjustment.

PubMed

Boerner, Katelynn E; Rosen, Natalie O

2015-06-01

Provoked vestibulodynia (PVD) is a common vulvovaginal pain condition associated with negative psychological and sexual consequences for affected women and their sexual partners. Greater pain acceptance has been found to be associated with better functional and psychological outcomes in individuals with chronic pain, and acceptance-based strategies are being increasingly incorporated into treatment protocols. The present study is a novel investigation of pain acceptance in PVD couples. The aim was to examine the associations between acceptance of vulvovaginal pain and women's pain during intercourse, as well as the psychological and sexual adjustment of both women with PVD and their partners. Sixty-one couples (M(age) for women = 27.95 years, SD = 5.87; M(age) for men = 30.48 years, SD = 6.70) in which the woman was diagnosed with PVD completed the Chronic Pain Acceptance Questionnaire, in reference to women's vulvovaginal pain. Women also rated their pain during intercourse, and couples completed measures of anxiety, depression, sexual function, and sexual satisfaction. Dependent measures were (i) women's self-reported pain during intercourse on a numerical rating scale; (ii) State-Trait Anxiety Inventory trait subscale; (iii) Beck Depression Inventory-II; (iv) Derogatis Interview for Sexual Functioning; and (v) Global Measure of Sexual Satisfaction Scale. Women's greater pain acceptance was associated with their lower self-reported pain during intercourse, controlling for partner's pain acceptance. Greater pain acceptance among women was associated with their own lower anxiety and depression, greater sexual functioning, as well as their own and their partner's greater sexual satisfaction, controlling for the partner's pain acceptance. Additionally, greater pain acceptance among male partners was associated with their own lower depression. Findings suggest that psychological interventions for PVD should target increasing couples' vulvovaginal pain acceptance in order to improve women's pain and the sexual and psychological functioning of both members of the couple. © 2015 International Society for Sexual Medicine.

Why Us? Perceived Injustice is Associated With More Sexual and Psychological Distress in Couples Coping With Genito-Pelvic Pain.

PubMed

Pâquet, Myriam; Bois, Katy; Rosen, Natalie O; Mayrand, Marie-Hélène; Charbonneau-Lefebvre, Véronique; Bergeron, Sophie

2016-01-01

Provoked vestibulodynia (PVD) is the most frequent cause of genito-pelvic pain/penetration disorder (GPPPD) and is associated with negative psychological and sexual consequences for affected women and their partners. PVD is often misdiagnosed or ignored and many couples may experience a sense of injustice, due to the loss of their ability to have a normal sexual life. Perceiving injustice has been documented to have important consequences in individuals with chronic pain. However, no quantitative research has investigated the experience of injustice in this population. The aim of this study was to investigate the associations between perceived injustice and pain, sexual satisfaction, sexual distress, and depression among women with PVD and their partners. Women diagnosed with PVD (N = 50) and their partners completed questionnaires of perceived injustice, pain, sexual satisfaction, sexual distress, and depression. (1) Global Measure of Sexual Satisfaction Scale; (2) Female Sexual Distress Scale; (3) Beck Depression Inventory-II; and (4) McGill-Melzack Pain Questionnaire. After controlling for partners' age, women's higher level of perceived injustice was associated with their own greater sexual distress, and the same pattern was found for partners. Women's higher level of perceived injustice was associated with their own greater depression, and the same pattern was found for partners. Women's higher perceived injustice was not associated with their own lower sexual satisfaction but partners' higher perceived injustice was associated with their own lower sexual satisfaction. Perceived injustice was not associated with women's pain intensity. Results suggest that perceiving injustice may have negative consequences for the couple's sexual and psychological outcomes. However, the effects of perceived injustice appear to be intra-individual. Targeting perceived injustice could enhance the efficacy of psychological interventions for women with PVD and their partners. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Effect of Suspension Plasma-Sprayed YSZ Columnar Microstructure and Bond Coat Surface Preparation on Thermal Barrier Coating Properties

NASA Astrophysics Data System (ADS)

Bernard, Benjamin; Quet, Aurélie; Bianchi, Luc; Schick, Vincent; Joulia, Aurélien; Malié, André; Rémy, Benjamin

2017-08-01

Suspension plasma spraying (SPS) is identified as promising for the enhancement of thermal barrier coating (TBC) systems used in gas turbines. Particularly, the emerging columnar microstructure enabled by the SPS process is likely to bring about an interesting TBC lifetime. At the same time, the SPS process opens the way to a decrease in thermal conductivity, one of the main issues for the next generation of gas turbines, compared to the state-of-the-art deposition technique, so-called electron beam physical vapor deposition (EB-PVD). In this paper, yttria-stabilized zirconia (YSZ) coatings presenting columnar structures, performed using both SPS and EB-PVD processes, were studied. Depending on the columnar microstructure readily adaptable in the SPS process, low thermal conductivities can be obtained. At 1100 °C, a decrease from 1.3 W m-1 K-1 for EB-PVD YSZ coatings to about 0.7 W m-1 K-1 for SPS coatings was shown. The higher content of porosity in the case of SPS coatings increases the thermal resistance through the thickness and decreases thermal conductivity. The lifetime of SPS YSZ coatings was studied by isothermal cyclic tests, showing equivalent or even higher performances compared to EB-PVD ones. Tests were performed using classical bond coats used for EB-PVD TBC coatings. Thermal cyclic fatigue performance of the best SPS coating reached 1000 cycles to failure on AM1 substrates with a β-(Ni,Pt)Al bond coat. Tests were also performed on AM1 substrates with a Pt-diffused γ-Ni/γ'-Ni3Al bond coat for which more than 2000 cycles to failure were observed for columnar SPS YSZ coatings. The high thermal compliance offered by both the columnar structure and the porosity allowed the reaching of a high lifetime, promising for a TBC application.

Impact of antiseptics on radical metabolism, antioxidant status and genotoxic stress in blood cells: povidone-iodine versus octenidine dihydrochloride.

PubMed

Wagner, Karl-Heinz; Jürss, Alice; Zarembach, Beate; Elmadfa, Ibrahim

2004-08-01

No sufficient data are available of the of antiseptics' influence on human blood cells. Effects of two antiseptics, povidone-iodine (PVD-I) versus octenidine dihydrochloride (OD), were tested on antioxidant status, radical formation, antioxidant defence enzymes and genotoxic stress in blood cells, in vitro. Human blood was taken by venipuncture, enriched with PVD-I or OD (0.0001-20% final concentration) and incubated at 37 degrees C between 30 and 120 min. alpha-Tocopherol was assessed in erythrocytes and granulocytes. Superoxide-dismutase (SOD) and glutathione (GSH) were determined in erythrocytes, the total anti-oxidative capacity (TAC) and malondialdehyde (MDA) in their ghosts. In granulocytes status of hydrogen peroxide (H(2)O(2)), superoxide anions and MDA was observed. Genotoxic stress was determined by counting sister chromatide exchanges (SCE) in lymphocytes after enrichment within 0.05-0.4% of antiseptics. Based on all biomarker tested, concentrations up to 0.05% incubated for 30 min did not affect cell metabolism. 1% and 10% PVD-I reduced the activity of SOD (-40%), GSH (-62%) and the content of alpha-tocopherol more than OD (p<0.05). No significant differences between the antiseptics were observed for TAC and MDA. H(2)O(2) and superoxide anions were significantly reduced after the 10% addition for both substances independent on the exposure. Without having changes in lipid oxidation, the reduction of antioxidative defence mechanisms must be due to the oxidation caused by the antiseptics, mainly PVD-I. An increased SCE rate was neither observed with PVD-I nor with OD within an enrichment with 0.05-0.4%. Higher concentrations (1% and more) could not be tested on SCE formation because they caused cell bursts. The results presented indicate that concentrations up to 0.05% incubated for 30 min are safe for exposing blood cells of healthy subjects.

Metal Organic Chemical Vapor Deposition of Oxide Films for Advanced Applications

DTIC Science & Technology

2000-06-01

coatings , photovoltaics, touch sensitive controls, electromagnetic shielding (as found on microwave ovens and stealth fighters), static dissipaters, and so...depositing high quality films. The methods are physical vapor deposition ( PVD ), spin/mist deposition, (CVD), and alternating layer (AL) CVD. PVD ...PZT & SBT, YBa2Cu3O, CeO, InO, TCOs, Varistors Ta2O5 , ZrO, MnO, HfO, CeO, MnO, MgO SAW/microwave Silicon/: Si, SiGe, SiGeC, �. Opto-electronics

Statistical characterization of surface features from tungsten-coated divertor inserts in the DIII-D Metal Rings Campaign

NASA Astrophysics Data System (ADS)

Adams, Jacob; Unterberg, Ezekial; Chrobak, Christopher; Stahl, Brian; Abrams, Tyler

2017-10-01

Continuing analysis of tungsten-coated inserts from the recent DIII-D Metal Rings Campaign utilizes a statistical approach to study carbon migration and deposition on W surfaces and to characterize the pre- versus post-exposure surface morphology. A TZM base was coated with W using both CVD and PVD and allowed for comparison between the two coating methods. The W inserts were positioned in the lower DIII-D divertor in both the upper (shelf) region and lower (floor) region and subjected to multiple plasma shots, primarily in H-mode. Currently, the post-exposure W inserts are being characterized using SEM/EDX to qualify the surface morphology and to quantify the surface chemical composition. In addition, profilometry is being used to measure the surface roughness of the inserts both before and after plasma exposure. Preliminary results suggest a correlation between the pre-exposure surface roughness and the level of carbon deposited on the surface. Furthermore, ongoing in-depth analysis may reveal insights into the formation mechanism of nanoscale bumps found in the carbon-rich regions of the W surfaces that have not yet been explained. Work supported in part by US DoE under the Science Undergraduate Laboratory Internship (SULI) program and under DE-FC02-04ER54698.

Sensory Neuron Fates Are Distinguished by a Transcriptional Switch that Regulates Dendrite Branch Stabilization

PubMed Central

Smith, Cody J.; O’Brien, Timothy; Chatzigeorgiou, Marios; Spencer, W. Clay; Feingold-Link, Elana; Husson, Steven J.; Hori, Sayaka; Mitani, Shohei; Gottschalk, Alexander; Schafer, William R.; Miller, David M.

2013-01-01

SUMMARY Sensory neurons adopt distinct morphologies and functional modalities to mediate responses to specific stimuli. Transcription factors and their downstream effectors orchestrate this outcome but are incompletely defined. Here, we show that different classes of mechanosensory neurons in C. elegans are distinguished by the combined action of the transcription factors MEC-3, AHR-1, and ZAG-1. Low levels of MEC-3 specify the elaborate branching pattern of PVD nociceptors, whereas high MEC-3 is correlated with the simple morphology of AVM and PVM touch neurons. AHR-1 specifies AVM touch neuron fate by elevating MEC-3 while simultaneously blocking expression of nociceptive genes such as the MEC-3 target, the claudin-like membrane protein HPO-30, that promotes the complex dendritic branching pattern of PVD. ZAG-1 exercises a parallel role to prevent PVM from adopting the PVD fate. The conserved dendritic branching function of the Drosophila AHR-1 homolog, Spineless, argues for similar pathways in mammals. PMID:23889932

Talking About Sex When Sex Is Painful: Dyadic Sexual Communication Is Associated With Women's Pain, and Couples' Sexual and Psychological Outcomes in Provoked Vestibulodynia.

PubMed

Rancourt, Kate M; Rosen, Natalie O; Bergeron, Sophie; Nealis, Logan J

2016-11-01

Provoked vestibulodynia (PVD) is a recurrent vulvovaginal pain condition associated with psychological and sexual consequences for affected women and their partners, including lower quality of dyadic sexual communication compared to pain-free couples. Although greater sexual communication is associated with positive sexual and relational outcomes for both pain-free couples and couples experiencing painful sex, little is known about its role in women's pain and psychological outcomes, especially in a relational context. The present study examined associations between dyadic sexual communication and pain, sexual satisfaction, sexual functioning, and depressive symptoms in a sample of 107 couples in which the woman was diagnosed with PVD via a standardized gynecological assessment. Women completed a measure of pain intensity, and both members of the couple completed measures of their dyadic sexual communication, sexual satisfaction, sexual functioning, and depressive symptoms. Analyses were guided by the actor-partner interdependence model. Women and partners' own perceptions of greater dyadic sexual communication were associated with their own greater sexual satisfaction and sexual functioning, and lower depressive symptoms. Partners' perceptions of greater dyadic sexual communication were also associated with women's lower pain and greater sexual satisfaction. Results point to the importance of dyadic coping conceptualizations for both individual and interpersonal outcomes in PVD. Dyadic sexual communication may be a key treatment target for interventions aimed at improving the pain and psychological and sexual impairments of women with PVD and their partners.

In Situ Ramp Anneal X-ray Diffraction Study of Atomic Layer Deposited Ultrathin TaN and Ta 1-x Al x N y Films for Cu Diffusion Barrier Applications

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

Consiglio, S.; Dey, S.; Yu, K.

2016-01-01

Ultrathin TaN and Ta 1-xAl xN y films with x = 0.21 to 0.88 were deposited by atomic layer deposition (ALD) and evaluated for Cu diffusion barrier effectiveness compared to physical vapor deposition (PVD) grown TaN. Cu diffusion barrier effectiveness was investigated using in-situ ramp anneal synchrotron X-ray diffraction (XRD) on Cu/1.8 nm barrier/Si stacks. A Kissinger-like analysis was used to assess the kinetics of Cu 3Si formation and determine the effective activation energy (E a) for Cu silicidation. Compared to the stack with a PVD TaN barrier, the stacks with the ALD films exhibited a higher crystallization temperature (Tmore » c) for Cu silicidation. The Ea values of Cu 3Si formation for stacks with the ALD films were close to the reported value for grain boundary diffusion of Cu whereas the Ea of Cu 3Si formation for the stack with PVD TaN is closer to the reported value for lattice diffusion. For 3 nm films, grazing incidence in-plane XRD showed evidence of nanocrystallites in an amorphous matrix with broad peaks corresponding to high density cubic phase for the ALD grown films and lower density hexagonal phase for the PVD grown film further elucidating the difference in initial failure mechanisms due to differences in barrier crystallinity and associated phase.« less

Morphological characteristics associated with rupture risk of multiple intracranial aneurysms.

PubMed

Wang, Guang-Xian; Liu, Lan-Lan; Wen, Li; Cao, Yun-Xing; Pei, Yu-Chun; Zhang, Dong

2017-10-01

To identify the morphological parameters that are related to intracranial aneurysms (IAs) rupture using a case-control model. A total of 107 patients with multiple IAs and aneurysmal subarachnoid hemorrhage between August 2011 and February 2017 were enrolled in this study. Characteristics of IAs location, shape, neck width, perpendicular height, depth, maximum size, flow angle, parent vessel diameter (PVD), aspect ratio (AR) and size ratio (SR) were evaluated using CT angiography. Multiple logistic regression analysis was used to identify the independent risk factors associated with IAs rupture. Receiver operating characteristic curve analysis was performed on the final model, and the optimal thresholds were obtained. IAs located in the internal carotid artery (ICA) was associated with a negative risk of rupture, whereas AR, SR1 (height/PVD) and SR2 (depth/PVD) were associated with increased risk of rupture. When SR was calculated differently, the odds ratio values of these factors were also different. The receiver operating characteristic curve showed that AR, SR1 and SR2 had cut-off values of 1.01, 1.48 and 1.40, respectively. SR3 (maximum size/PVD) was not associated with IAs rupture. IAs located in the ICA are associated with a negative risk of rupture, while high AR (>1.01), SR1 (>1.48) or SR2 (>1.40) are risk factors for multiple IAs rupture. Copyright © 2017 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.

Posterior vitreous detachment induced by nattokinase (subtilisin NAT): a novel enzyme for pharmacologic vitreolysis.

PubMed

Takano, Akiomi; Hirata, Akira; Ogasawara, Kazuya; Sagara, Nina; Inomata, Yasuya; Kawaji, Takahiro; Tanihara, Hidenobu

2006-05-01

To investigate the effects of intravitreal injection of nattokinase (subtilisin NAT), a serine protease that is produced by Bacillus subtilis (natto), for induction of posterior vitreous detachment (PVD). Different doses of nattokinase (1, 0.1, or 0.01 fibrin-degradation units [FU]) or physiologic saline as a control were injected into the vitreous cavity of rabbit eyes. Scanning electron microscopy was used to observe the retinal surfaces of four rabbit eyes per concentration. Histologic alterations were assessed by light microscopy, using four eyes from each group. Electroretinography (ERG) was performed to observe retinal function, ranging from 1 hour to 1 week after the nattokinase (1 or 0.1 FU) or saline solution administration, using four eyes from each group at each time point. Also, findings in all rabbits were monitored by slit lamp examination and by indirect ophthalmoscopy with a 20-D lens. Scanning electron microscopy showed smooth retinal surfaces, indicating the occurrence of PVD at 30 minutes after intervention in all the experimental eyes injected with 0.1 or 1.0 FU nattokinase, but none of the control eyes. Light microscopy and ERG analysis showed no critical change even after the use of 0.1 FU nattokinase, an amount sufficient to induce PVD. However, toxicity in the forms of preretinal hemorrhage and ERG changes was noted with the higher dose (1 FU) of nattokinase. The results suggested that nattokinase is a useful enzyme for pharmacologic vitreolysis because of its efficacy in inducing PVD.

Attachment, Sexual Assertiveness, and Sexual Outcomes in Women with Provoked Vestibulodynia and Their Partners: A Mediation Model.

PubMed

Leclerc, Bianca; Bergeron, Sophie; Brassard, Audrey; Bélanger, Claude; Steben, Marc; Lambert, Bernard

2015-08-01

Provoked vestibulodynia (PVD) is a prevalent women's sexual pain disorder, which is associated with sexual function difficulties. Attachment theory has been used to understand adult sexual outcomes, providing a useful framework for examining sexual adaptation in couples confronted with PVD. Research to date indicates that anxious and avoidant attachment dimensions correlate with worse sexual outcomes in community and clinical samples. The present study examined the association between attachment, pain, sexual function, and sexual satisfaction in a sample of 101 couples in which the women presented with PVD. The actor-partner interdependence model was used in order to investigate both actor and partner effects. This study also examined the role of sexual assertiveness as a mediator of these associations via structural equation modeling. Women completed measures of pain intensity and both members of the couple completed measures of romantic attachment, sexual assertiveness, sexual function, and satisfaction. Results indicated that attachment dimensions did not predict pain intensity. Both anxious and avoidant attachment were associated with lower sexual satisfaction. Only attachment avoidance predicted lower sexual function in women. Partner effects indicated that higher sexual assertiveness in women predicted higher sexual satisfaction in men. Finally, women's sexual assertiveness was found to be a significant mediator of the relationship between their attachment dimensions, sexual function, and satisfaction. Findings highlight the importance of examining how anxious and avoidant attachment may lead to difficulties in sexual assertiveness and to less satisfying sexual interactions in couples where women suffer from PVD.

Inkjet Deposition of Layer by Layer Assembled Films

PubMed Central

Andres, Christine M.; Kotov, Nicholas A.

2010-01-01

Layer-by-layer assembly (LBL) can create advanced composites with exceptional properties unavailable by other means, but the laborious deposition process and multiple dipping cycles hamper their utilization in microtechnologies and electronics. Multiple rinse steps provide both structural control and thermodynamic stability to LBL multilayers but they significantly limit their practical applications and contribute significantly to the processing time and waste. Here we demonstrate that by employing inkjet technology one can deliver the necessary quantities of LBL components required for film build-up without excess, eliminating the need for repetitive rinsing steps. This feature differentiates this approach from all other recognized LBL modalities. Using a model system of negatively charged gold nanoparticles and positively charged poly(diallyldimethylammonium) chloride, the material stability, nanoscale control over thickness and particle coverage offered by the inkjet LBL technique are shown to be equal or better than the multilayers made with traditional dipping cycles. The opportunity for fast deposition of complex metallic patterns using a simple inkjet printer was also shown. The additive nature of LBL deposition based on the formation of insoluble nanoparticle-polyelectrolyte complexes of various compositions provides an excellent opportunity for versatile, multi-component, and non-contact patterning for the simple production of stratified patterns that are much needed in advanced devices. PMID:20863114

Modeling of the interaction between osteoblasts and biocompatible substrates as a function of adhesion strength.

PubMed

Portan, D V; Deligianni, D D; Deligianni, K; Kroustalli, A A; Tyllianakis, M; Papanicolaou, G C

2018-03-01

A goal of current implantology research is to design devices that induce controlled, guided, and rapid healing. Nanoscale structured substrates [e.g., titania nanotubes (TNTs) or carbon nanotubes (CNTs)] dramatically improve the functions of conventional biomaterials. The present investigation evaluated the behavior of osteoblasts cells cultured on smooth and nanostructured substrates, by measuring osteoblasts specific biomarkers [alkaline phosphatase (AP) and total protein] and cells adhesion strength to substrates, followed by semi-empirical modeling to predict the experimental results. Findings were in total agreement with the current state of the art. The proliferation, as well as the AP and total protein levels were higher on the nanostructure phases (TNTs, CNTs) comparing to the smooth ones (plastic and pure titanium). Cells adhesion strength measured was found higher on the nanostructured materials. This coincided with a higher value of proteins which are directly implicated in the process of adherence. Results were accurately predicted through the Viscoelastic Hybrid Interphase Model. A gradual adherence of bone cells to implants using multilayered biomaterials that involve biodegradable polymeric films and a nanoscale modification of titanium surface is suggested to improve performance through an interphase-mediated osteointegration of orthopedic implants. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 621-628, 2018. © 2017 Wiley Periodicals, Inc.

Design and construction of a DNA origami drug delivery system based on MPT64 antibody aptamer for tuberculosis treatment.

PubMed

Ranjbar, Reza; Hafezi-Moghadam, Mohammad Sadegh

2016-02-01

With all of the developments on infectious diseases, tuberculosis (TB) remains a cause of death among people. One of the most promising assembly techniques in nano-technology is "scaffolded DNA origami" to design and construct a nano-scale drug delivery system. Because of the global health problems of tuberculosis, the development of potent new anti-tuberculosis drug delivery system without cross-resistance with known anti-mycobacterial agents is urgently needed. The aim of this study was to design a nano-scale drug delivery system for TB treatment using the DNA origami method. In this study, we presented an experimental research on a DNA drug delivery system for treating Tuberculosis. TEM images were visualized with an FEI Tecnai T12 BioTWIN at 120 kV. The model was designed by caDNAno software and computational prediction of the 3D solution shape and its flexibility was calculated with a CanDo server. Synthesizing the product was imaged using transmission electron microscopy after negative-staining by uranyl formate. We constructed a multilayer 3D DNA nanostructure system by designing square lattice geometry with the scaffolded-DNA-origami method. With changes in the lock and key sequences, we recommend that this system be used for other infectious diseases to target the pathogenic bacteria.

Direct-current triboelectricity generation by a sliding Schottky nanocontact on MoS2 multilayers

NASA Astrophysics Data System (ADS)

Liu, Jun; Goswami, Ankur; Jiang, Keren; Khan, Faheem; Kim, Seokbeom; McGee, Ryan; Li, Zhi; Hu, Zhiyu; Lee, Jungchul; Thundat, Thomas

2018-02-01

The direct conversion of mechanical energy into electricity by nanomaterial-based devices offers potential for green energy harvesting1-3. A conventional triboelectric nanogenerator converts frictional energy into electricity by producing alternating current (a.c.) triboelectricity. However, this approach is limited by low current density and the need for rectification2. Here, we show that continuous direct-current (d.c.) with a maximum density of 106 A m-2 can be directly generated by a sliding Schottky nanocontact without the application of an external voltage. We demonstrate this by sliding a conductive-atomic force microscope tip on a thin film of molybdenum disulfide (MoS2). Finite element simulation reveals that the anomalously high current density can be attributed to the non-equilibrium carrier transport phenomenon enhanced by the strong local electrical field (105-106 V m-2) at the conductive nanoscale tip4. We hypothesize that the charge transport may be induced by electronic excitation under friction, and the nanoscale current-voltage spectra analysis indicates that the rectifying Schottky barrier at the tip-sample interface plays a critical role in efficient d.c. energy harvesting. This concept is scalable when combined with microfabricated or contact surface modified electrodes, which makes it promising for efficient d.c. triboelectricity generation.

Electric field-assisted deposition of nanowires on carbon nanotubes for nanoelectronics and sensor applications.

PubMed

Sivakumar, Kousik; Panchapakesan, Balaji

2005-02-01

Manipulation and control of matter at the nanoscale and atomic scale levels are crucial for the success of nanoscale sensors and actuators. The ability to control and synthesize multilayer structures using carbon nanotubes that will enable the building of electronic devices within a nanotube is still in its infancy. In this paper, we present results on selective electric field-assisted deposition of metals on carbon nanotubes realizing metallic nanowire structures. Silver and platinum nanowires have been fabricated using this approach for their applications in chemical sensing as catalytic materials to sniff toxic agents and in the area of biomedical nanotechnology for construction of artificial muscles. Electric field-assisted deposition allows the deposition of metals with a high degree of selectivity on carbon nanotubes by manipulating the charges on the surface of the nanotubes and forming electrostatic double-layer supercapacitors. Deposition of metals primarily occurred due to electrochemical reduction, electrophoresis, and electro-osmosis inside the walls of the nanotube. SEM and TEM investigations revealed silver and platinum nanowires between 10 nm and 100 nm in diameter. The present technique is versatile and enables the fabrication of a host of different types of metallic and semiconducting nanowires using carbon nanotube templates for nanoelectronics and a myriad of sensor applications.

Ability and efficiency of an automatic analysis software to measure microvascular parameters.

PubMed

Carsetti, Andrea; Aya, Hollmann D; Pierantozzi, Silvia; Bazurro, Simone; Donati, Abele; Rhodes, Andrew; Cecconi, Maurizio

2017-08-01

Analysis of the microcirculation is currently performed offline, is time consuming and operator dependent. The aim of this study was to assess the ability and efficiency of the automatic analysis software CytoCamTools 1.7.12 (CC) to measure microvascular parameters in comparison with Automated Vascular Analysis (AVA) software 3.2. 22 patients admitted to the cardiothoracic intensive care unit following cardiac surgery were prospectively enrolled. Sublingual microcirculatory videos were analysed using AVA and CC software. The total vessel density (TVD) for small vessels, perfused vessel density (PVD) and proportion of perfused vessels (PPV) were calculated. Blood flow was assessed using the microvascular flow index (MFI) for AVA software and the averaged perfused speed indicator (APSI) for the CC software. The duration of the analysis was also recorded. Eighty-four videos from 22 patients were analysed. The bias between TVD-CC and TVD-AVA was 2.20 mm/mm 2 (95 % CI 1.37-3.03) with limits of agreement (LOA) of -4.39 (95 % CI -5.66 to -3.16) and 8.79 (95 % CI 7.50-10.01) mm/mm 2 . The percentage error (PE) for TVD was ±32.2 %. TVD was positively correlated between CC and AVA (r = 0.74, p < 0.001). The bias between PVD-CC and PVD-AVA was 6.54 mm/mm 2 (95 % CI 5.60-7.48) with LOA of -4.25 (95 % CI -8.48 to -0.02) and 17.34 (95 % CI 13.11-21.57) mm/mm 2 . The PE for PVD was ±61.2 %. PVD was positively correlated between CC and AVA (r = 0.66, p < 0.001). The median PPV-AVA was significantly higher than the median PPV-CC [97.39 % (95.25, 100 %) vs. 81.65 % (61.97, 88.99), p < 0.0001]. MFI categories cannot estimate or predict APSI values (p = 0.45). The time required for the analysis was shorter with CC than with AVA system [2'42″ (2'12″, 3'31″) vs. 16'12″ (13'38″, 17'57″), p < 0.001]. TVD is comparable between the two softwares, although faster with CC software. The values for PVD and PPV are not interchangeable given the different approach to assess microcirculatory flow.

Posterior Vitreous Detachment With Microplasmin Alters the Retinal Penetration of Intravitreal Bevacizumab (Avastin) in Rabbit Eyes

PubMed Central

Goldenberg, David T.; Giblin, Frank J.; Cheng, Mei; Chintala, Shravan K.; Trese, Michael T.; Drenser, Kimberly A.; Ruby, Alan J.

2010-01-01

Purpose Intravitreal bevacizumab (Avastin) is frequently used for the treatment of age-related macular degeneration. Previous studies have demonstrated full thickness retinal penetration. Intravitreal recombinant microplasmin (MP) has been shown to successfully induce a posterior vitreous detachment (PVD) and vitreous liquefaction in animals. It has been suggested that a PVD may alter the retinal penetration of molecules in the vitreous cavity. The aim of this study was to compare bevacizumab (BV) retinal penetration in rabbit eyes with and without a MP-induced PVD. Methods Twelve adult rabbits were injected with 0.1 ml (0.4 mg) of MP into the vitreous cavity of one eye. One week later, the rabbits were injected with 0.05 ml (1.25 mg) of BV into both eyes. Both eyes of three rabbits each were harvested at 6, 12, 24, and 72 hours after the BV injection. Frozen retinal cross sections were prepared, and BV retinal penetration was evaluated with immunohistochemistry using a fluorescence-labeled antibody against BV. Two eyes from one rabbit were not injected with either agent and used as controls to compare the background autofluorescence. Peripapillary retinal sections were recorded with a digital camera, and intra-retinal BV fluorescence-labeled antibody was measured by qualitative photographic interpretation. Two additional rabbits received an intravitreal injection of 0.1 ml of MP in one eye. One week later, both eyes from each rabbit were enucleated and frozen retinal sections were prepared and analyzed with light microscopy to evaluate for histologic damage. Results Full thickness BV retinal penetration was observed throughout the retina in both eyes of each rabbit. All of the MP-injected eyes exhibited increased antibody labeling in retinas evaluated 6, 12, and 24 hours after BV injection when compared with the contralateral non-MP-injected eyes. By three days after BV injection, all eyes demonstrated decreased antibody labeling compared to earlier time periods. At three days, one rabbit showed increased antibody labeling in the retina of the non-MP-injected eye compared with the contralateral MP-injected eye, and two rabbits exhibited similar antibody labeling in both eyes. When compared with control eyes, light microscopy demonstrated normal retinal histologic findings in eyes injected only with microplasmin. Conclusions Increased BV retinal penetration is observed initially in eyes with a MP-induced PVD, and the mechanism is likely multifactorial. By three days, retinal penetration is similar in eyes with and without a PVD. Although it is difficult to directly extrapolate to humans, our study suggests a PVD may alter the retinal penetration of BV. PMID:21099453

Layer-by-layer assembly of nanostructured composites: Mechanics and applications

NASA Astrophysics Data System (ADS)

Podsiadlo, Paul

The development of efficient methods for preparation of nanometer-sized materials and our evolving ability to manipulate the nanoscale objects have brought about a scientific and technological revolution called: nanotechnology. This revolution has been especially driven by discovery of unique nanoscale properties of the nanomaterials which are governed by their inherent size. Today, the total societal impact of nanotechnology is expected to be greater than the combined influences that the silicon integrated circuit, medical imaging, computer-aided engineering, and man-made polymers have had in the last century. Many nanomaterials were also found to possess exceptional mechanical properties. This led to tremendous interest into developing composite materials by exploiting the mechanical properties of these building blocks. In spite of a tremendous volume of work done in the field, preparation of such nanocomposites (NCs) has proven to be elusive due to inability of traditional "top-down" fabrication approaches to effectively harness properties of the nano-scale building blocks. This thesis focuses on preparation of organic/inorganic and solely organic NCs via a bottom-up nano-manufacturing approach called the layer-by-layer (LBL) assembly. Two natural and inexpensive nanoscale building blocks are explored: nanosheets of Na+-montmorillonite clay (MTM) and rod-shaped nanocrystals of cellulose (CNRs). In the first part of the thesis, we present results from systematic study of mechanics of MTM-based NCs. Different compositions are explored with a goal of understanding the nanoscale mechanics. Ultimately, development of a transparent composite with record-high strength and stiffness is presented. In the second part, we present results from LBL assembly of the CNRs. We demonstrate feasibility of assembly and mechanical properties of the resulting films. We also demonstrate preparation of LBL films with anti- reflective properties from tunicate (a sea animal) CNRs. In the final part, we show preparation of high toughness and hierarchically organized NCs using two concepts: "exponential" LBL (e-LBL) assembly and charged polyurethanes. We show preparation of novel e-LBL structures and highly flexible LBL multilayers. We also demonstrate preparation of macro-scale composites from hierarchical, post-assembly consolidation of LBL sheets. This last result represents a potential paradigm change in the practice of LBL assembly by enabling transformation of the thin-films into macro-scale structures.

A new diffusion-inhibited oxidation-resistant coating for superalloys

NASA Technical Reports Server (NTRS)

Gedwill, M. A.; Glasgow, T. K.; Levine, S. R.

1981-01-01

A concept for enhanced protection of superalloys consists of adding an oxidation- and diffusion-resistant cermet layer between the superalloy and the outer oxidation-resistant metallic alloy coating. Such a duplex coating was compared with a physical-vapor-deposited (PVD) NiCrAlY coating in cyclic oxidation at 1150 C. The substrate alloy was MA 754 - an oxide-dispersion-strengthened superalloy that is difficult to coat. The duplex coating, applied by plasma spraying, outperformed the PVD coating on the basis of weight change and both macroscopic and metallographic observations.

Harmful or helpful: perceived solicitous and facilitative partner responses are differentially associated with pain and sexual satisfaction in women with provoked vestibulodynia.

PubMed

Rosen, Natalie O; Bergeron, Sophie; Glowacka, Maria; Delisle, Isabelle; Baxter, Mary Lou

2012-09-01

Provoked vestibulodynia (PVD) is a highly prevalent vulvovaginal pain condition that negatively affects women's emotional, sexual, and relationship well-being. Recent studies have investigated the role of interpersonal variables, including partner responses. We examined whether solicitous and facilitative partner responses were differentially associated with vulvovaginal pain and sexual satisfaction in women with PVD by examining each predictor while controlling for the other. One hundred twenty-one women (M age = 30.60, SD = 10.53) with PVD or self-reported symptoms of PVD completed the solicitous subscale of the spouse response scale of the Multidimensional Pain Inventory, and the facilitative subscale of the Spouse Response Inventory. Participants also completed measures of pain, sexual function, sexual satisfaction, trait anxiety, and avoidance of pain and sexual behaviors (referred to as "avoidance"). Dependent measures were the (i) Pain Rating Index of the McGill Pain Questionnaire with reference to pain during vaginal intercourse and (ii) Global Measure of Sexual Satisfaction Scale. Controlling for trait anxiety and avoidance, higher solicitous partner responses were associated with higher vulvovaginal pain intensity (β = 0.20, P = 0.03), and higher facilitative partner responses were associated with lower pain intensity (β = -0.20, P = 0.04). Controlling for sexual function, trait anxiety, and avoidance, higher facilitative partner responses were associated with higher sexual satisfaction (β = 0.15, P = 0.05). Findings suggest that facilitative partner responses may aid in alleviating vulvovaginal pain and improving sexual satisfaction, whereas solicitous partner responses may contribute to greater pain. © 2012 International Society for Sexual Medicine.

A common pronociceptive pain modulation profile typifying subgroups of chronic pelvic pain syndromes is interrelated with enhanced clinical pain.

PubMed

Grinberg, Keren; Granot, Michal; Lowenstein, Lior; Abramov, Liora; Weissman-Fogel, Irit

2017-06-01

Provoked vestibulodynia (PVD) and painful bladder syndrome (PBS), subgroups of chronic pelvic pain syndromes (CPPS), are considered to share common biophysiological peripheral mechanisms. In addition, indications of a pronociceptive pain profile coexisting with psychological vulnerability suggest common dysfunctional pain processing and pain modulation in these 2 subgroups of CPPS. We therefore aimed at comparing the pain profile and psychological traits of patients with PVD and PBS to see whether the pain profile contributes to intersubject variability of clinical pain symptoms. Patients with PVD (n = 18) and PBS (n = 21) were compared with healthy controls (n = 20) in their responses to (1) pain psychophysical tests applied to both referred (suprapubis) and remote (hand) body areas and (2) pain-related psychological factors (pain catastrophizing, depression, anxiety, and somatization). We found a similar pronociceptive pain profile in the 2 subgroups of CPPS-enhanced facilitation (ie, hyperalgesia in the referred body area [P < 0.001]) and inefficient inhibition (ie, reduced conditioned pain modulation [P < 0.001] that were associated with both enhanced pain ratings evoked during trigger point examination [P < 0.037]) and higher Brief Pain Inventory ratings (P = 0.002). The latter was also correlated with pain catastrophizing (r = 0.504, P = 0.001) and depression symptoms (r = 0.361, P = 0.024). The findings suggest common mechanisms underlying a dysfunctional nociceptive system in both PVD and PBS. The intersubject variability in the level of dysfunction and its association with disease severity recommends a personalized pain treatment that may alleviate daily pain and dysfunction in patients with CPPS.

Nanoscale investigation of platinum nanoparticles on strontium titanium oxide grown via physical vapor deposition and atomic layer deposition

NASA Astrophysics Data System (ADS)

Christensen, Steven Thomas

This dissertation examines growth of platinum nanoparticles from vapor deposition on SrTiO3 using a characterization approach that combines imaging techniques and X-ray methods. The primary suite of characterization probes includes atomic force microscopy (AFM), grazing-incidence small-angle X-ray scattering (GISAXS), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and X-ray absorption spectroscopy (XAS). The vapor deposition techniques include physical vapor deposition (PVD) by evaporation and atomic layer deposition (ALD). For the PVD platinum study, AFM/XRF showed ˜10 nm nanoparticles separated by an average of 100 nm. The combination of AFM, GISAXS, and XRF indicated that the nanoparticles observed with AFM were actually comprised of closely spaced, smaller nanoparticles. These conclusions were supported by high-resolution SEM. The unusual behavior of platinum nanoparticles to aggregate without coalescence or sintering was observed previously by other researchers using transmissision electron microscopy (TEM). Platinum nanoparticle growth was also investigated on SrTiO3 (001) single crystals using ALD to nucleate nanoparticles that subsequently grew and coalesced into granular films as the ALD progresses. The expected growth rate for the early stages of ALD showed a two-fold increase which was attributed to the platinum deposition occurring faster on the bare substrate. Once the nanoparticles had coalesced into a film, steady state ALD growth proceeded. The formation of nanoparticles was attributed to the atomic diffusion of platinum atoms on the surface in addition to direct growth from the ALD precursor gases. The platinum ALD nanoparticles were also studied on SrTiO3 nanocube powders. The SrTiO3 nanocubes average 60 nm on a side and the cube faces have a {001} orientation. The ALD proceeded in a similar fashion as on the single crystal substrates where the deposition rate was twice as fast as the steady state growth rate. The Pt nanoparticle size increased linearly starting at ˜0.7 nm for 1 ALD cycle to ˜3 nm for 5 ALD cycles. The platinum chemical state was also investigated using X-ray absorption spectroscopy. Platinum nanoparticles ˜1 nm or smaller tended to be oxidized. For larger nanoparticles, the platinum state systematically approached that of bulk platinum metal as the size (number of ALD cycles) increased. The platinum loading was exceptionally low, ˜10 -3 mg cm-2.

Engineering and characterizing nanoscale multilayered structures for magnetic tunnel junctions

NASA Astrophysics Data System (ADS)

Yang, J. Joshua

Magnetic tunnel junction (MTJ) has generated considerable attention due to its potential applications in improved magnetic sensors, read heads in HDDs and nonvolatile RAM. The materials issues play a crucial role in the performance of MTJs. In the work described in this thesis, we have engineered some interesting nanoscale multilayered structures mainly via thermodynamics considerations for MTJs. The insulator is usually an ultra-thin (<2nm) oxide, formed by oxidizing a pre-deposited metal, such as Al etc. We have developed novel fabrication approaches for obtaining clean and smooth interfaces between the insulator and the ferromagnets. These approaches include selectively oxidizing the pre-deposited tunnel barrier precursor metal, amorphizing the tunnel barrier precursor metal by alloying it with other elements, and in-situ annealing the bottom ferromagnetic layer. About 72% tunneling magnetoresistance (TMR) has been achieved at room temperature with AlOx and CoFe based MTJs. We have made a systemic study of the TMR vs. the Co1-xFe x electrode composition for AlOx based MTJs. A significant variation of TMR with Fe concentration has been observed. It is well known that the crystal structure of Co1-xFex changes from fcc to bcc with increasing Fe concentration. The concomitant composition change cast doubts on the role played by the crystal structure of the Co1-x Fex electrode on the TMR. By introducing different strains to an epitaxial Co1-xFex layer, we were able to fix its composition but alter its crystalline structure from fcc to bcc and found that the bcc structure resulted in much higher TMR values than found for the fcc structure. This is one of the few direct experimental confirmatory results showing the role of the FM electronic structure on the MTJ properties. Using Ag as a template, different 3d ferromagnets have been epitaxially grown on the Si substrate with hcp, fcc and bcc crystalline structures, respectively. By combining the selective oxidation method with the epitaxial growth technique, we have successfully created a single-crystal-like layer on top of an amorphous layer, which may have broad applications in thin film devices including MTJs.

Instantaneous formation of SiOx nanocomposite for high capacity lithium ion batteries by enhanced disproportionation reaction during plasma spray physical vapor deposition.

PubMed

Tashiro, Tohru; Dougakiuchi, Masashi; Kambara, Makoto

2016-01-01

Nanocomposite SiO x particles have been produced by a single step plasma spray physical vapor deposition (PS-PVD) through rapid condensation of SiO vapors and the subsequent disproportionation reaction. Core-shell nanoparticles, in which 15 nm crystalline Si is embedded within the amorphous SiO x matrix, form under typical PS-PVD conditions, while 10 nm amorphous particles are formed when processed with an increased degree of non-equilibrium effect. Addition of CH 4 promotes reduction in the oxygen content x of SiO x , and thereby increases the Si volume in a nanocomposite particle. As a result, core-shell nanoparticles with x  = 0.46 as anode exhibit increased initial efficiency and the capacity of lithium ion batteries while maintaining cyclability. Furthermore, it is revealed that the disproportionation reaction of SiO is promoted in nanosized particles attaining increased Si diffusivity by two orders of magnitude compared to that in bulk, which facilitates instantaneous composite nanoparticle formation during PS-PVD.

Solid-State Lithium Conductors for Lithium Metal Batteries Based on Electrospun Nanofiber/Plastic Crystal Composites.

PubMed

Zhou, Yundong; Wang, Xiaoen; Zhu, Haijin; Yoshizawa-Fujita, Masahiro; Miyachi, Yukari; Armand, Michel; Forsyth, Maria; Greene, George W; Pringle, Jennifer M; Howlett, Patrick C

2017-08-10

Organic ionic plastic crystals (OIPCs) are a class of solid-state electrolytes with good thermal stability, non-flammability, non-volatility, and good electrochemical stability. When prepared in a composite with electrospun polyvinylidene fluoride (PVdF) nanofibers, a 1:1 mixture of the OIPC N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([C 2 mpyr][FSI]) and lithium bis(fluorosulfonyl)imide (LiFSI) produced a free-standing, robust solid-state electrolyte. These high-concentration Li-containing electrolyte membranes had a transference number of 0.37(±0.02) and supported stable lithium symmetric-cell cycling at a current density of 0.13 mA cm -2 . The effect of incorporating PVdF in the Li-containing plastic crystal was investigated for different ratios of PVdF and [Li][FSI]/[C 2 mpyr][FSI]. In addition, Li|LiNi 1/3 Co 1/3 Mn 1/3 O 2 cells were prepared and cycled at ambient temperature and displayed a good rate performance and stability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Instantaneous formation of SiOx nanocomposite for high capacity lithium ion batteries by enhanced disproportionation reaction during plasma spray physical vapor deposition

PubMed Central

Tashiro, Tohru; Dougakiuchi, Masashi; Kambara, Makoto

2016-01-01

Abstract Nanocomposite SiOx particles have been produced by a single step plasma spray physical vapor deposition (PS-PVD) through rapid condensation of SiO vapors and the subsequent disproportionation reaction. Core-shell nanoparticles, in which 15 nm crystalline Si is embedded within the amorphous SiOx matrix, form under typical PS-PVD conditions, while 10 nm amorphous particles are formed when processed with an increased degree of non-equilibrium effect. Addition of CH4 promotes reduction in the oxygen content x of SiOx, and thereby increases the Si volume in a nanocomposite particle. As a result, core-shell nanoparticles with x = 0.46 as anode exhibit increased initial efficiency and the capacity of lithium ion batteries while maintaining cyclability. Furthermore, it is revealed that the disproportionation reaction of SiO is promoted in nanosized particles attaining increased Si diffusivity by two orders of magnitude compared to that in bulk, which facilitates instantaneous composite nanoparticle formation during PS-PVD. PMID:27933114

Max Phase Materials And Coatings For High Temperature Heat Transfer Applications

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

Martinez-Rodriguez, M.; Garcia-Diaz, B.; Olson, L.

2015-10-19

Molten salts have been used as heat transfer fluids in a variety of applications within proposed Gen IV nuclear designs and in advanced power system such as Concentrating Solar Power (CSP). However, operating at elevated temperatures can cause corrosion in many materials. This work developed coating technologies for MAX phase materials on Haynes-230 and characterized the corrosion of the coatings in the presence of commercial MgCl 2-KCl molten salt. Cold spraying of Ti 2AlC and physical vapor deposition (PVD) of Ti 2AlC or Zr 2AlC were tested to determine the most effective form of coating MAX phases on structural substrates.more » Corrosion testing at 850°C for 100 hrs showed that 3.9 μm Ti2AlC by PVD was slightly protective while 117 μm Ti 2AlC by cold spray and 3.6 μm Zr 2AlC by PVD were completely protective. None of the tests showed decomposition of the coating (Ti or Zr) into the salt« less

Friction and fretting wear characteristics of different diamond-like carbon coatings against alumina in water-lubricated fretting conditions.

PubMed

Watabe, Tsukasa; Amanov, Auezhan; Tsuboi, Ryo; Sasaki, Shinya

2013-12-01

Diamond-like carbon (DLC) coatings typically show low friction and high wear resistance. In this study, the friction and fretting wear characteristics of PVD, CVD and CVD-Si DLC coatings were investigated against an alumina (Al2O3) ball under water-lubricated fretting conditions. The objective of this study is to investigate and compare the friction and fretting wear characteristics of those DLC coatings at various fretting frequencies. The test results showed that the PVD DLC coating led to a lower friction coefficient and a higher resistance to fretting wear compared to those of the CVD and CVD-Si DLC coatings. However, the CVD DLC coating showed that the fretting wear resistance decreases with increasing frequency, while no significant difference in fretting wear resistances of the PVD and CVD-Si DLC coatings was observed. Quantitative surface analyses of the specimens were performed using an energy dispersive spectroscopy (EDS), a laser scanning microscope (LSM), a scanning electron microscope (SEM), an atomic force microscope (AFM) and the Raman spectroscopy.

Morphology and inhibition performance of Ag thin film as antimicrobial coating deposited by RF-PVD on 316 L stainless steel

NASA Astrophysics Data System (ADS)

Purniawan, A.; Khrisna, Y. S. A.; Rasyida, A.; Atmono, T. M.

2018-04-01

Foreign body related infection (FBRIs) is caused by forming biofilm of bacterial colony of medical equipment surfaces. In many cases, the FBRIs is still happened on the surface after medical sterilization process has been performed. In order to avoid the case, surface modification by antimicrobial coating was used. In this work, we present silver (Ag) thin film on 316 L stainless steel substrate surface was deposited using Radio Frequency Sputtering PVD (RF-PVD). The morphology of Ag thin film were characterized using SEM-EDX. Surface roughness of the thin film was measured by AFM. In addition, Kirby Bauer Test in Escherichia coli (E. coli) was conducted in order to evaluate the inhibition performance of the Ag thin film antimicrobial coating. Based on SEM and AFM results show that the particle size is increased from 523 nm to 708 nm and surface roughness from 9 to 20 nm for deposition time 10 minutes to 20 minutes, respectively. In addition, the inhibition layer of the coating is about 29 mm.

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

Ma, Ying; Li, Hong; Bridges, Denzel

We report that the continuing miniaturization of microelectronics is pushing advanced manufacturing into nanomanufacturing. Nanojoining is a bottom-up assembly technique that enables functional nanodevice fabrication with dissimilar nanoscopic building blocks and/or molecular components. Various conventional joining techniques have been modified and re-invented for joining nanomaterials. Our review surveys recent progress in nanojoining methods, as compared to conventional joining processes. Examples of nanojoining are given and classified by the dimensionality of the joining materials. At each classification, nanojoining is reviewed and discussed according to materials specialties, low dimensional processing features, energy input mechanisms and potential applications. The preparation of new intermetallicmore » materials by reactive nanoscale multilayer foils based on self-propagating high-temperature synthesis is highlighted. This review will provide insight into nanojoining fundamentals and innovative applications in power electronics packaging, plasmonic devices, nanosoldering for printable electronics, 3D printing and space manufacturing.« less

Mimicking the colourful wing scale structure of the Papilio blumei butterfly.

PubMed

Kolle, Mathias; Salgard-Cunha, Pedro M; Scherer, Maik R J; Huang, Fumin; Vukusic, Pete; Mahajan, Sumeet; Baumberg, Jeremy J; Steiner, Ullrich

2010-07-01

The brightest and most vivid colours in nature arise from the interaction of light with surfaces that exhibit periodic structure on the micro- and nanoscale. In the wings of butterflies, for example, a combination of multilayer interference, optical gratings, photonic crystals and other optical structures gives rise to complex colour mixing. Although the physics of structural colours is well understood, it remains a challenge to create artificial replicas of natural photonic structures. Here we use a combination of layer deposition techniques, including colloidal self-assembly, sputtering and atomic layer deposition, to fabricate photonic structures that mimic the colour mixing effect found on the wings of the Indonesian butterfly Papilio blumei. We also show that a conceptual variation to the natural structure leads to enhanced optical properties. Our approach offers improved efficiency, versatility and scalability compared with previous approaches.

Experimental correlation between nonlinear optical and magnetotransport properties observed in Au-Co thin films

DOE PAGES

Yang, Kaida; Kryutyanskiy, Victor; Kolmychek, Irina; ...

2016-01-01

Magnetic materials where at least one dimension is in the nanometer scale typically exhibit different magnetic, magnetotransport, and magnetooptical properties compared to bulk materials. Composite magnetic thin films where the matrix composition, magnetic cluster size, and overall composite film thickness can be experimentally tailored via adequate processing or growth parameters offer a viable nanoscale platform to investigate possible correlations between nonlinear magnetooptical and magnetotransport properties, since both types of properties are sensitive to the local magnetization landscape. As a result, it has been shown that the local magnetization contrast affects the nonlinear magnetooptical properties as well as the magnetotransport propertiesmore » in magnetic-metal/nonmagnetic metal multilayers; thus, nanocomposite films showcase another path to investigate possible correlations between these distinct properties which may prove useful for sensing applications.« less

A crossover in anisotropic nanomechanochemistry of van der Waals crystals

NASA Astrophysics Data System (ADS)

Shimamura, Kohei; Misawa, Masaaki; Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Shimojo, Fuyuki; Vashishta, Priya

2015-12-01

In nanoscale mechanochemistry, mechanical forces selectively break covalent bonds to essentially control chemical reactions. An archetype is anisotropic detonation of layered energetic molecular crystals bonded by van der Waals (vdW) interactions. Here, quantum molecular dynamics simulations reveal a crossover of anisotropic nanomechanochemistry of vdW crystal. Within 10-13 s from the passage of shock front, lateral collision produces NO2 via twisting and bending of nitro-groups and the resulting inverse Jahn-Teller effect, which is mediated by strong intra-layer hydrogen bonds. Subsequently, as we transition from heterogeneous to homogeneous mechanochemical regimes around 10-12 s, shock normal to multilayers becomes more reactive, producing H2O assisted by inter-layer N-N bond formation. These time-resolved results provide much needed atomistic understanding of nanomechanochemistry that underlies a wider range of technologies.

Quantitative first-principles theory of interface absorption in multilayer heterostructures

DOE PAGES

Hachtel, Jordan A.; Sachan, Ritesh; Mishra, Rohan; ...

2015-09-03

The unique chemical bonds and electronic states of interfaces result in optical properties that are different from those of the constituting bulk materials. In the nanoscale regime, the interface effects can be dominant and impact the optical response of devices. Using density functional theory (DFT), the interface effects can be calculated, but DFT is computationally limited to small systems. In this paper, we describe a method to combine DFT with macroscopic methodologies to extract the interface effect on absorption in a consistent and quantifiable manner. The extracted interface effects are an independent parameter and can be applied to more complicatedmore » systems. Finally, we demonstrate, using NiSi 2/Si heterostructures, that by varying the relative volume fractions of interface and bulk, we can tune the spectral range of the heterostructure absorption.« less

Daily associations between partner responses and sexual and relationship satisfaction in couples coping with provoked vestibulodynia.

PubMed

Rosen, Natalie O; Muise, Amy; Bergeron, Sophie; Delisle, Isabelle; Baxter, Mary Lou

2015-04-01

Women with provoked vestibulodynia (PVD) experience a recurrent vulvo-vaginal pain triggered primarily during sexual intercourse. Although affected couples report adverse effects on their sexual and global romantic relationships, few studies have examined interpersonal factors that may influence their sexual and relationship satisfaction. Cross-sectional studies have shown that greater partner solicitous and negative responses and lower facilitative responses are associated with poorer sexual and relationship satisfaction in women with PVD. The aim of this study was to investigate the within-person associations between partner responses to painful intercourse and the sexual and relationship satisfaction of affected couples. In a dyadic daily experience study, 69 women (M(age) = 28.46, SD = 6.66) diagnosed with PVD and their cohabitating male partners (M(age) = 30.29, SD = 8.13) reported on male partner responses, as well as sexual and relationship satisfaction on sexual intercourse days (M = 6.81; SD = 5.40) over 8 weeks. Dependent measures were the (i) Kansas Marital Satisfaction Scale and (ii) Global Measure of Sexual Satisfaction Scale. On sexual intercourse days when women perceived more facilitative partner responses than usual and on days when they perceived lower negative partner responses than usual, they reported higher sexual and relationship satisfaction. On sexual intercourse days when men reported more solicitous responses than usual, both they and their female partners reported lower sexual satisfaction. Interventions aimed at improving the day-to-day sexual and relationship satisfaction of couples with PVD should target increasing facilitative and decreasing negative and solicitous partner responses. © 2015 International Society for Sexual Medicine.

Preoperative care of Polypoid exposed mucosal template in bladder exstrophy: the role of high-barrier plastic wraps in reducing inflammation and polyp size.

PubMed

Sabetkish, Nastaran; Sabetkish, Shabnam; Kajbafzadeh, Abdol-Mohammad

2018-01-26

To assess the role of high-barrier plastic wrap in reducing the number and size of polyps, as well as decreasing the inflammation and allergic reactions in exstrophy cases, and to compare the results with the application of low-barrier wrap. Eight patients with bladder exstrophy-epispadias complex (BEEC) that had used a low density polyethylene (LDPE) wrap for coverage of the exposed polypoid bladder in preoperative care management were referred. The main complaint of their parents was increase in size and number of polyps. After a period of 2 months using the same wrap and observing the increasing pattern in size of polyps, these patients were recommended to use a high-barrier wrap which is made of polyvinylidene chloride (PVdC), until closure. Patients were monitored for the number and size of polyps before and after the change of barriers. The incidence of para-exstrophy skin infection/inflammation and skin allergy were assessed. Biopsies were taken from the polyps to identify histopathological characteristics of the exposed polyps. The high barrier wrap was applied for a mean ± SD duration of 12±2.1 months. Polyps' size and number decreased after 12 months. No allergic reaction was detected in patients after the usage of PVdC; three patients suffered from low-grade skin allergy when LDPE was applied. Also, pre-malignant changes were observed in none of the patients in histopathological examination after the application of PVdC. Polyps' size and number and skin allergy may significantly decrease with the use of a high-barrier wrap. Certain PVdC wraps with more integrity and less evaporative permeability may be more "exstrophy-friendly". Copyright® by the International Brazilian Journal of Urology.

Development of Low Density Titanium Alloys for Structural Applications

NASA Technical Reports Server (NTRS)

Froes, F. H.; Suryanarayana, C.; Powell, C.; Ward-Close, C. Malcolm; Wilkes, D. M. J.

1996-01-01

In this report the results of a program designed to reduce the density of titanium by adding magnesium are presented. Because these two elements are immiscible under conventional ingot metallurgy techniques, two specialized powder metallurgy methods namely, mechanical alloying (MA) and physical vapor deposition (PVD) were implemented. The mechanical alloying experiments were done both at the University of Idaho and at the Defense Research Agency in UK. Since titanium is reactive with interstitial elements, a secondary goal of this research was to correlate solubility extensions with interstitial contamination content, especially oxygen and nitrogen. MA was carried out in SPEX 8000 shaker mils and different milling containers were utilized to control the level of contamination. Results showed that solubilities of Mg in Ti were obtained up to 28 at.% (16.4 wt. %) Mg in Ti for Ti-39.6 at. % (25 wt. %) Mg alloys, which greatly exceed those obtained under equilibrium conditions. This reflects a density reduction of approximately 26 %. Contamination of oxygen and nitrogen seemed to increase the solubility of magnesium in titanium in some cases; however, we were not able to make a clear correlation between contamination levels with solubilities. Work at the DRA has emphasized optimization of present PVD equipment, specifically composition and temperature control. Preliminary PVD data has shown Ti-Mg deposits have successfully been made up to 2 mm thick and that solubility extensions were achieved. The potential for density reduction of titanium by alloying with magnesium has been demonstrated; however, this work has only scratched the surface of the development of such low density alloys. Much research is needed before such alloys could be implemented into industry. Further funding is required in order to optimize the MA/PVD processes including contamination control, determination of optimal alloy compositions, microstructure development, and mechanical property determination.

The inter-arm blood pressure difference and peripheral vascular disease: cross-sectional study.

PubMed

Clark, Christopher E; Campbell, John L; Powell, Roy J; Thompson, John F

2007-10-01

A blood pressure (BP) difference between the upper limbs is often encountered in primary care. Knowledge of its prevalence and importance in the accurate measurement of BP is poor, representing a source of error. Current hypertension guidelines do not emphasize this. To establish the prevalence of an inter-arm blood pressure difference (IAD) and explore its association with other indicators of peripheral vascular disease (PVD) in a hypertensive primary care population. This was a cross-sectional study. Primary care, one rural general practice, was the setting of the study. The methods were controlled simultaneous measurement of brachial BPs, ankle-brachial pressure index (ABPI) and tiptoe stress testing in 94 subjects. In all, 18 of 94 [19%, 95% confidence interval (CI) 11-27%] subjects had mean systolic inter-arm difference (sIAD) > or =10 mmHg and seven of 94 (7%, 95% CI 2-12%) had mean diastolic inter-arm difference (dIAD) > or =10 mmHg. Nineteen of 91 (20%, 95% CI 12-28%) had a reduced ABPI <0.9. There was negative correlation between systolic (Pearson's correlation coefficient - 0.378; P = 0.01) and diastolic (Pearson's correlation coefficient - 0.225; P = 0.05) magnitudes of IAD with ABPI. On tiptoe testing, 9/90 subjects (10%, 95% CI 4-16%) had a pressure drop > or =20%. An IAD and asymptomatic PVD are common in a primary care hypertensive population. Magnitude of the IAD is inversely correlated with ABPI, supporting the hypotheses that IADs are causally linked to PVD, and that IAD is a useful marker for the presence of PVD. Consequently, detection of an IAD should prompt the clinician to screen subjects for other signs of vascular disease and target them for aggressive cardiovascular risk factor modification.

Cost-Utility of Evaluation for Posterior Vitreous Detachment and Prophylaxis of Retinal Detachment.

PubMed

Yannuzzi, Nicolas A; Chang, Jonathan S; Brown, Gary C; Smiddy, William E

2018-01-01

To evaluate the costs and cost-utility of examination for posterior vitreous detachment (PVD) and treatment of associated pathology, and of managing various other peripheral retinal disorders to prevent retinal detachment (RD). A decision analysis model of cost-utility. There were no participants. Published retrospective data on the natural course of PVD, retinal tears, and lattice degeneration were used to quantitate the visual benefits of examination and treatment. Center for Medicare and Medicaid Services data were used to calculate associated modeled costs in a hospital/facility-based and nonfacility/ambulatory surgical center (ASC)-based setting. Published standards of utility for a given level of visual acuity were used to derive costs and quality-adjusted life years (QALYs). Cost of evaluation and treatment, utility of defined health states, QALY, and cost per QALY. The modeled cost of evaluation of a patient with PVD and treatment of associated pathology in the facility/hospital (nonfacility/ASC)-based setting was $65 to $190 ($25-$71) depending on whether a single or 2-examination protocol was used. The cost per QALY saved was $255 to $638/QALY ($100-$239/QALY). Treatment of a symptomatic horseshoe tear resulted in a net cost savings of $1749 ($1314) and improved utility, whereas treatment of an asymptomatic horseshoe tear resulted in $2981/QALY ($1436/QALY). Treatment of asymptomatic lattice degeneration in an eye in which the fellow eye had a history of RD resulted in $4414/QALY ($2187/QALY). Evaluation and management of incident acute PVD (and symptomatic horseshoe tears) offer a low cost and a favorable cost-utility (low $/QALY) as a result of the minimization of the cost and morbidity associated with the development of RD, thus justifying current practice standards. Copyright © 2017 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Variable Expressivity of a Founder Mutation in the EIF2AK4 Gene in Hereditary Pulmonary Veno-occlusive Disease and Its Impact on Survival.

PubMed

Navas Tejedor, Paula; Palomino Doza, Julián; Tenorio Castaño, Jair Antonio; Enguita Valls, Ana Belén; Rodríguez Reguero, José Julián; Martínez Meñaca, Amaya; Hernández González, Ignacio; Bueno Zamora, Héctor; Lapunzina Badía, Pablo Daniel; Escribano Subías, Pilar

2018-02-01

Hereditary pulmonary veno-occlusive disease (PVOD) has been associated with biallelic mutations in EIF2AK4 with the recent discovery of a founder mutation in Iberian Romani patients with familial PVOD. The aims of this study were phenotypical characterization and survival analysis of Iberian Romani patients with familial PVOD carrying the founder p.Pro1115Leu mutation in EIF2AK4, according to their tolerance to pulmonary vasodilators (PVD). Familial genetic screening was conducted, as well as assessment of sociocultural determinants with a potential influence on disease course. Observational study of Romani patients with familial PVOD included in the Spanish Registry of Pulmonary Arterial Hypertension. Genetic screening of EIF2AK4 was performed in index cases and relatives between November 2011 and July 2016 and histological pulmonary examination was carried out in patients who received a lung transplant or died. The patients were divided into 2 groups depending on their tolerance to PVD, with comparison of baseline characteristics and survival free of death or lung transplant. Eighteen Romani patients were included: 9 index cases and 9 relatives. The biallelic founder mutation in EIF2AK4 was found in all affected cases and 2 unaffected relatives. Family screening showed 34.2% of healthy heterozygotes, high consanguinity, young age at childbirth, and frequent multiparity. Prognosis was bleak, with significant differences depending on tolerance to PVD. We describe 2 phenotypes of hereditary PVOD depending on tolerance to PVD, with prognostic impact and familial distribution. Consanguinity may have a negative impact on the transmission of PVOD, with familial genetic screening showing high effectiveness. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Relation of Thermal Conductivity with Process Induced Anisotropic Void Systems in EB-PVD PYSZ Thermal Barrier Coatings

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

Renteria, A. Flores; Saruhan-Brings, B.; Ilavsky, J.

2008-03-03

Thermal barrier coatings (TBCs) deposited by Electron-beam physical deposition (EB-PVD) protect the turbine blades situated at the high pressure sector of the aircraft and stationary turbines. It is an important task to uphold low thermal conductivity in TBCs during long-term service at elevated temperatures. One of the most promising methods to fulfil this task is to optimize the properties of PYSZ-based TBC by tailoring its microstructure. Thermal conductivity of the EB-PVD produced PYSZ TBCs is influenced mainly by the size, shape, orientation and volume of the various types of porosity present in the coatings. These pores can be classified asmore » open (inter-columnar and between feather arms gaps) and closed (intra-columnar pores). Since such pores are located within the three-dimensionally deposited columns and enclose large differences in their sizes, shapes, distribution and anisotropy, the accessibility for their characterization is very complex and requires the use of sophisticated methods. In this work, three different EB-PVD TBC microstructures were manufactured by varying the process parameters, yielding various characteristics of their pores. The corresponding thermal conductivities in as-coated state and after ageing at 11000C/1h and 100h were measured via Laser Flash Analysis Method (LFA). The pore characteristics and their individual effect on the thermal conductivity are analysed by USAXS which is supported by subsequent modelling and LFA methods, respectively. Evident differences in the thermal conductivity values of each microstructure were found in as-coated and aged conditions. In summary, broader columns introduce higher values in thermal conductivity. In general, thermal conductivity increases after ageing for all three investigated microstructures, although those with initial smaller pore surface area show smaller changes.« less

Relation of thermal conductivity with process induced anisotropic void system in EB-PVD PYSZ thermal barrier coatings.

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

Renteria, A. F.; Saruhan, B.; Ilavsky, J.

2007-01-01

Thermal barrier coatings (TBCs) deposited by Electron-beam physical deposition (EB-PVD) protect the turbine blades situated at the high pressure sector of the aircraft and stationary turbines. It is an important task to uphold low thermal conductivity in TBCs during long-term service at elevated temperatures. One of the most promising methods to fulfil this task is to optimize the properties of PYSZ-based ,TBC by tailoring its microstructure. Thermal conductivity of the EB-PVD produced PYSZ TBCs is influenced mainly by the size, shape, orientation and volume of the various types of porosity present in the coatings. These pores can be classified asmore » open (inter-columnar and between feather arms gaps) and closed (intra-columnar pores). Since such pores are located within the three-dimensionally deposited columns and enclose large differences in their sizes, shapes, distribution and anisotropy, the accessibility for their characterization is very complex and requires the use of sophisticated methods. In this work, three different EB-PVD TBC microstructures were manufactured by varying the process parameters, yielding various characteristics of their pores. The corresponding thermal conductivities in as-coated state and after ageing at 1100C/1h and 100h were measured via Laser Flash Analysis Method (LFA). The pore characteristics and their individual effect on the thermal conductivity are analysed by USAXS which is supported by subsequent modelling and LFA methods, respectively. Evident differences in the thermal conductivity values of each microstructure were found in as-coated and aged conditions. In summary, broader columns introduce higher values in thermal conductivity. In general, thermal conductivity increases after ageing for all three investigated microstructures, although those with initial smaller pore surface area show smaller changes.« less

Enhancing Insights into Pulmonary Vascular Disease through a Precision Medicine Approach. A Joint NHLBI-Cardiovascular Medical Research and Education Fund Workshop Report.

PubMed

Newman, John H; Rich, Stuart; Abman, Steven H; Alexander, John H; Barnard, John; Beck, Gerald J; Benza, Raymond L; Bull, Todd M; Chan, Stephen Y; Chun, Hyung J; Doogan, Declan; Dupuis, Jocelyn; Erzurum, Serpil C; Frantz, Robert P; Geraci, Mark; Gillies, Hunter; Gladwin, Mark; Gray, Michael P; Hemnes, Anna R; Herbst, Roy S; Hernandez, Adrian F; Hill, Nicholas S; Horn, Evelyn M; Hunter, Kendall; Jing, Zhi-Cheng; Johns, Roger; Kaul, Sanjay; Kawut, Steven M; Lahm, Tim; Leopold, Jane A; Lewis, Greg D; Mathai, Stephen C; McLaughlin, Vallerie V; Michelakis, Evangelos D; Nathan, Steven D; Nichols, William; Page, Grier; Rabinovitch, Marlene; Rich, Jonathan; Rischard, Franz; Rounds, Sharon; Shah, Sanjiv J; Tapson, Victor F; Lowy, Naomi; Stockbridge, Norman; Weinmann, Gail; Xiao, Lei

2017-06-15

The Division of Lung Diseases of the NHLBI and the Cardiovascular Medical Education and Research Fund held a workshop to discuss how to leverage the anticipated scientific output from the recently launched "Redefining Pulmonary Hypertension through Pulmonary Vascular Disease Phenomics" (PVDOMICS) program to develop newer approaches to pulmonary vascular disease. PVDOMICS is a collaborative, protocol-driven network to analyze all patient populations with pulmonary hypertension to define novel pulmonary vascular disease (PVD) phenotypes. Stakeholders, including basic, translational, and clinical investigators; clinicians; patient advocacy organizations; regulatory agencies; and pharmaceutical industry experts, joined to discuss the application of precision medicine to PVD clinical trials. Recommendations were generated for discussion of research priorities in line with NHLBI Strategic Vision Goals that include: (1) A national effort, involving all the stakeholders, should seek to coordinate biosamples and biodata from all funded programs to a web-based repository so that information can be shared and correlated with other research projects. Example programs sponsored by NHLBI include PVDOMICS, Pulmonary Hypertension Breakthrough Initiative, the National Biological Sample and Data Repository for PAH, and the National Precision Medicine Initiative. (2) A task force to develop a master clinical trials protocol for PVD to apply precision medicine principles to future clinical trials. Specific features include: (a) adoption of smaller clinical trials that incorporate biomarker-guided enrichment strategies, using adaptive and innovative statistical designs; and (b) development of newer endpoints that reflect well-defined and clinically meaningful changes. (3) Development of updated and systematic variables in imaging, hemodynamic, cellular, genomic, and metabolic tests that will help precisely identify individual and shared features of PVD and serve as the basis of novel phenotypes for therapeutic interventions.

Role of Iron Uptake Systems in Pseudomonas aeruginosa Virulence and Airway Infection

PubMed Central

Minandri, Fabrizia; Imperi, Francesco; Frangipani, Emanuela; Bonchi, Carlo; Visaggio, Daniela; Facchini, Marcella; Pasquali, Paolo; Bragonzi, Alessandra

2016-01-01

Pseudomonas aeruginosa is a leading cause of hospital-acquired pneumonia and chronic lung infections in cystic fibrosis patients. Iron is essential for bacterial growth, and P. aeruginosa expresses multiple iron uptake systems, whose role in lung infection deserves further investigation. P. aeruginosa Fe3+ uptake systems include the pyoverdine and pyochelin siderophores and two systems for heme uptake, all of which are dependent on the TonB energy transducer. P. aeruginosa also has the FeoB transporter for Fe2+ acquisition. To assess the roles of individual iron uptake systems in P. aeruginosa lung infection, single and double deletion mutants were generated in P. aeruginosa PAO1 and characterized in vitro, using iron-poor media and human serum, and in vivo, using a mouse model of lung infection. The iron uptake-null mutant (tonB1 feoB) and the Fe3+ transport mutant (tonB1) did not grow aerobically under low-iron conditions and were avirulent in the mouse model. Conversely, the wild type and the feoB, hasR phuR (heme uptake), and pchD (pyochelin) mutants grew in vitro and caused 60 to 90% mortality in mice. The pyoverdine mutant (pvdA) and the siderophore-null mutant (pvdA pchD) grew aerobically in iron-poor media but not in human serum, and they caused low mortality in mice (10 to 20%). To differentiate the roles of pyoverdine in iron uptake and virulence regulation, a pvdA fpvR double mutant defective in pyoverdine production but expressing wild-type levels of pyoverdine-regulated virulence factors was generated. Deletion of fpvR in the pvdA background partially restored the lethal phenotype, indicating that pyoverdine contributes to the pathogenesis of P. aeruginosa lung infection by combining iron transport and virulence-inducing capabilities. PMID:27271740

Growth, structure and stability of sputter-deposited MoS2 thin films.

PubMed

Kaindl, Reinhard; Bayer, Bernhard C; Resel, Roland; Müller, Thomas; Skakalova, Viera; Habler, Gerlinde; Abart, Rainer; Cherevan, Alexey S; Eder, Dominik; Blatter, Maxime; Fischer, Fabian; Meyer, Jannik C; Polyushkin, Dmitry K; Waldhauser, Wolfgang

2017-01-01

Molybdenum disulphide (MoS 2 ) thin films have received increasing interest as device-active layers in low-dimensional electronics and also as novel catalysts in electrochemical processes such as the hydrogen evolution reaction (HER) in electrochemical water splitting. For both types of applications, industrially scalable fabrication methods with good control over the MoS 2 film properties are crucial. Here, we investigate scalable physical vapour deposition (PVD) of MoS 2 films by magnetron sputtering. MoS 2 films with thicknesses from ≈10 to ≈1000 nm were deposited on SiO 2 /Si and reticulated vitreous carbon (RVC) substrates. Samples deposited at room temperature (RT) and at 400 °C were compared. The deposited MoS 2 was characterized by macro- and microscopic X-ray, electron beam and light scattering, scanning and spectroscopic methods as well as electrical device characterization. We find that room-temperature-deposited MoS 2 films are amorphous, of smooth surface morphology and easily degraded upon moderate laser-induced annealing in ambient conditions. In contrast, films deposited at 400 °C are nano-crystalline, show a nano-grained surface morphology and are comparatively stable against laser-induced degradation. Interestingly, results from electrical transport measurements indicate an unexpected metallic-like conduction character of the studied PVD MoS 2 films, independent of deposition temperature. Possible reasons for these unusual electrical properties of our PVD MoS 2 thin films are discussed. A potential application for such conductive nanostructured MoS 2 films could be as catalytically active electrodes in (photo-)electrocatalysis and initial electrochemical measurements suggest directions for future work on our PVD MoS 2 films.

Growth, structure and stability of sputter-deposited MoS2 thin films

PubMed Central

Bayer, Bernhard C; Resel, Roland; Müller, Thomas; Skakalova, Viera; Habler, Gerlinde; Abart, Rainer; Cherevan, Alexey S; Eder, Dominik; Blatter, Maxime; Fischer, Fabian; Meyer, Jannik C; Polyushkin, Dmitry K; Waldhauser, Wolfgang

2017-01-01

Molybdenum disulphide (MoS2) thin films have received increasing interest as device-active layers in low-dimensional electronics and also as novel catalysts in electrochemical processes such as the hydrogen evolution reaction (HER) in electrochemical water splitting. For both types of applications, industrially scalable fabrication methods with good control over the MoS2 film properties are crucial. Here, we investigate scalable physical vapour deposition (PVD) of MoS2 films by magnetron sputtering. MoS2 films with thicknesses from ≈10 to ≈1000 nm were deposited on SiO2/Si and reticulated vitreous carbon (RVC) substrates. Samples deposited at room temperature (RT) and at 400 °C were compared. The deposited MoS2 was characterized by macro- and microscopic X-ray, electron beam and light scattering, scanning and spectroscopic methods as well as electrical device characterization. We find that room-temperature-deposited MoS2 films are amorphous, of smooth surface morphology and easily degraded upon moderate laser-induced annealing in ambient conditions. In contrast, films deposited at 400 °C are nano-crystalline, show a nano-grained surface morphology and are comparatively stable against laser-induced degradation. Interestingly, results from electrical transport measurements indicate an unexpected metallic-like conduction character of the studied PVD MoS2 films, independent of deposition temperature. Possible reasons for these unusual electrical properties of our PVD MoS2 thin films are discussed. A potential application for such conductive nanostructured MoS2 films could be as catalytically active electrodes in (photo-)electrocatalysis and initial electrochemical measurements suggest directions for future work on our PVD MoS2 films. PMID:28685112

Calcium Binding-Mediated Sustained Release of Minocycline from Hydrophilic Multilayer Coatings Targeting Infection and Inflammation

PubMed Central

Zhang, Zhiling; Nix, Camilla A.; Ercan, Utku K.; Gerstenhaber, Jonathan A.; Joshi, Suresh G.; Zhong, Yinghui

2014-01-01

Infection and inflammation are common complications that seriously affect the functionality and longevity of implanted medical implants. Systemic administration of antibiotics and anti-inflammatory drugs often cannot achieve sufficient local concentration to be effective, and elicits serious side effects. Local delivery of therapeutics from drug-eluting coatings presents a promising solution. However, hydrophobic and thick coatings are commonly used to ensure sufficient drug loading and sustained release, which may limit tissue integration and tissue device communications. A calcium-mediated drug delivery mechanism was developed and characterized in this study. This novel mechanism allows controlled, sustained release of minocycline, an effective antibiotic and anti-inflammatory drug, from nanoscale thin hydrophilic polyelectrolyte multilayers for over 35 days at physiologically relevant concentrations. pH-responsive minocycline release was observed as the chelation between minocycline and Ca2+ is less stable at acidic pH, enabling ‘smart’ drug delivery in response to infection and/or inflammation-induced tissue acidosis. The release kinetics of minocycline can be controlled by varying initial loading, Ca2+ concentration, and Ca2+ incorporation into different layers, enabling facile development of implant coatings with versatile release kinetics. This drug delivery platform can potentially be used for releasing any drug that has high Ca2+ binding affinity, enabling its use in a variety of biomedical applications. PMID:24409292

Fabrication and characterization of microstructures created in thermally deposited arsenic trisulfide by multiphoton lithography

NASA Astrophysics Data System (ADS)

Schwarz, Casey M.; Grabill, Chris N.; Richardson, Gerald D.; Labh, Shreya; Lewis, Anna M.; Vyas, Aadit; Gleason, Benn; Rivero-Baleine, Clara; Richardson, Kathleen A.; Pogrebnyakov, Alexej; Mayer, Theresa S.; Kuebler, Stephen M.

2017-04-01

A detailed study of multiphoton lithography (MPL) in arsenic trisulfide (As2S3) films and the effects on nanoscale morphology, chemical networking, and the appearance of the resulting features by the chemical composition, deposition rate, etch processing, and inclusion of an antireflection (AR) layer of As2Se3 between the substrate and the As2S3 layer is reported. MPL was used to photo-pattern nanostructured arrays in single- and multilayer films. The variation in chemical composition for laser-exposed, UV-exposed, and unexposed films is correlated with the etch response, nanostructure formation, and deposition conditions. Reflection of the focused beam at the substrate back into the film produces standing wave interference that modulates the exposure with distance from the substrate and produces nanobead structures. The interference and the modulation can be controlled by the addition of an AR layer of As2Se3 deposited between the substrate and the As2S3 film. Relative to structures produced in a single-layer As2S3 film having no AR layer, photo-patterning in the multilayer As2S3-on-As2Se3 film yields pillar-shaped structures that are closer to the targeted shape and are narrower (120 versus 320 nm), more uniform, and better adhering to the substrate. Processing methods are demonstrated for fabricating large-area arrays with diffractive optical function.

Time-resolved atomic force microscopy imaging studies of asymmetric PS-b-PMMA ultrathin films: Dislocation and disclination transformations, defect mobility, and evolution of nanoscale morphology

NASA Astrophysics Data System (ADS)

Hahm, J.; Sibener, S. J.

2001-03-01

Time-sequenced atomic force microscopy (AFM) studies of ultrathin films of cylinder-forming polystyrene-block-polymethylmethacrylate (PS-b-PMMA) copolymer are presented which delineate thin film mobility kinetics and the morphological changes which occur in microphase-separated films as a function of annealing temperature. Of particular interest are defect mobilities in the single layer (L thick) region, as well as the interfacial morphological changes which occur between L thick and adjacent 3L/2 thick layers, i.e., structural changes which occur during multilayer evolution. These measurements have revealed the dominant pathways by which disclinations and dislocations transform, annihilate, and topologically evolve during thermal annealing of such films. Mathematical combining equations are given to better explain such defect transformations and show the topological outcomes which result from defect-defect encounters. We also report a collective, Arrhenius-type flow of defects in localized L thick regions of the film; these are characterized by an activation energy of 377 kJ/mol. These measurements represent the first direct investigation of time-lapse interfacial morphological changes including associated defect evolution pathways for polymeric ultrathin films. Such observations will facilitate a more thorough and predictive understanding of diblock copolymer thin film dynamics, which in turn will further enable the utilization of these nanoscale phase-separated materials in a range of physical and chemical applications.

Effect of nano-scale characteristics of graphene on electrochemical performance of activated carbon supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Jasni, M. R. M.; Deraman, M.; Suleman, M.; Hamdan, E.; Sazali, N. E. S.; Nor, N. S. M.; Shamsudin, S. A.

2016-02-01

Graphene with its typical nano-scale characteristic properties has been widely used as an additive in activated carbon electrodes in order to enhance the performance of the electrodes for their use in high performance supercapacitors. Activated carbon monoliths (ACMs) electrodes have been prepared by carbonization and activation of green monoliths (GMs) of pre-carbonized fibers of oil palm empty fruit bunches or self-adhesive carbon grains (SACGs) and SACGs added with 6 wt% of KOH-treated multi-layer graphene. ACMs electrodes have been assembled in symmetrical supercapacitor cells that employed aqueous KOH electrolyte (6 M). The cells have been tested with cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge discharge methods to investigate the effect of graphene addition on the specific capacitance (Csp), specific energy (E), specific power (P), equivalent series resistance (ESR) and response time (τo) of the supercapacitor cells. The results show that the addition of graphene in the GMs change the values of Csp, Emax, Pmax, ESR and τo from (61-96) F/g, 2 Wh/kg, 104 W/kg, 2.6 Ω and 38 s, to the respective values of (110-124) F/g, 3 Wh/kg, 156 W/kg, 3.4 Ω and 63 s. This study demonstrates that the graphene addition in the GMs has a significant effect on the electrochemical behavior of the electrodes.

Flexible free-standing TiO2/graphene/PVdF films as anode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Ren, H. M.; Ding, Y. H.; Chang, F. H.; He, X.; Feng, J. Q.; Wang, C. F.; Jiang, Y.; Zhang, P.

2012-12-01

Graphene composites were prepared by hydrothermal method using titanium dioxide (TiO2) adsorbed graphene oxide (GO) sheets as precursors. Free-standing hybrid films for lithium-ion batteries were prepared by adding TiO2/graphene composites to the polyvinylidene fluoride (PVdF)/N-methyl-2-pyrrolidone (NMP) solution, followed by a solvent evaporation technique. These films were characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and various electrochemical techniques. Flexible films show an excellent cycling performance, which was attributed to the interconnected graphene conducting network, which depressed the increasing of electric resistance during the cycling.

Conductivity of gel polymer electrolytes doped with solutions of phosphonic acid or protic ionic liquids

NASA Astrophysics Data System (ADS)

Shmukler, Liudmila E.; Fadeeva, Yuliya A.; Glushenkova, Ekaterina V.; Nguyen, Van Thuc; Safonova, Liubov P.

2018-04-01

The proton-conducting gel electrolytes (PCGEs) based on PMMA, PVdF or PVdF-HFP doped with solutions of phosphonic acid or ammonium based protic ionic liquids (PILs) in DMF have been synthesized. Rather high values of the conductivity (10-4-10-3 S cm-1) have been reached at low dopant concentrations (up to 1 mol l-1). The influence of the nature of both polymeric matrix and dopant as well as dopant concentration on the conductivity values was discussed. It was established that the dependence of conductivity on the nature of dopant, but not the polymeric matrix, was more pronounced.

PVD thermal barrier coating applications and process development for aircraft engines

NASA Astrophysics Data System (ADS)

Rigney, D. V.; Viguie, R.; Wortman, D. J.; Skelly, D. W.

1997-06-01

Thermal barrier coatings (TBCs) have been developed for application to aircraft engine components to improve service life in an increasingly hostile thermal environment. The choice of TBC type is related to the component, intended use, and economics. Selection of electron beam physical vapor deposition proc-essing for turbine blade is due in part to part size, surface finish requirements, thickness control needs, and hole closure issues. Process development of PVD TBCs has been carried out at several different sites, including GE Aircraft Engines (GEAE). The influence of processing variables on microstructure is dis-cussed, along with the GEAE development coater and initial experiences of pilot line operation.

High throughput production of nanocomposite SiO x powders by plasma spray physical vapor deposition for negative electrode of lithium ion batteries.

PubMed

Homma, Keiichiro; Kambara, Makoto; Yoshida, Toyonobu

2014-04-01

Nanocomposite Si/SiO x powders were produced by plasma spray physical vapor deposition (PS-PVD) at a material throughput of 480 g h -1 . The powders are fundamentally an aggregate of primary ∼20 nm particles, which are composed of a crystalline Si core and SiO x shell structure. This is made possible by complete evaporation of raw SiO powders and subsequent rapid condensation of high temperature SiO x vapors, followed by disproportionation reaction of nucleated SiO x nanoparticles. When CH 4 was additionally introduced to the PS-PVD, the volume of the core Si increases while reducing potentially the SiO x shell thickness as a result of the enhanced SiO reduction, although an unfavorable SiC phase emerges when the C/Si molar ratio is greater than 1. As a result of the increased amount of Si active material and reduced source for irreversible capacity, half-cell batteries made of PS-PVD powders with C/Si = 0.25 have exhibited improved initial efficiency and maintenance of capacity as high as 1000 mAh g -1 after 100 cycles at the same time.

Experimental study of three-dimensional fin-channel charge trapping flash memories with titanium nitride and polycrystalline silicon gates

NASA Astrophysics Data System (ADS)

Liu, Yongxun; Matsukawa, Takashi; Endo, Kazuhiko; O'uchi, Shinichi; Tsukada, Junichi; Yamauchi, Hiromi; Ishikawa, Yuki; Mizubayashi, Wataru; Morita, Yukinori; Migita, Shinji; Ota, Hiroyuki; Masahara, Meishoku

2014-01-01

Three-dimensional (3D) fin-channel charge trapping (CT) flash memories with different gate materials of physical-vapor-deposited (PVD) titanium nitride (TiN) and n+-polycrystalline silicon (poly-Si) have successfully been fabricated by using (100)-oriented silicon-on-insulator (SOI) wafers and orientation-dependent wet etching. Electrical characteristics of the fabricated flash memories including statistical threshold voltage (Vt) variability, endurance, and data retention have been comparatively investigated. It was experimentally found that a larger memory window and a deeper erase are obtained in PVD-TiN-gated metal-oxide-nitride-oxide-silicon (MONOS)-type flash memories than in poly-Si-gated poly-Si-oxide-nitride-oxide-silicon (SONOS)-type memories. The larger memory window and deeper erase of MONOS-type flash memories are contributed by the higher work function of the PVD-TiN metal gate than of the n+-poly-Si gate, which is effective for suppressing electron back tunneling during erase operation. It was also found that the initial Vt roll-off due to the short-channel effect (SCE) is directly related to the memory window roll-off when the gate length (Lg) is scaled down to 46 nm or less.

Manifestation of Crystal Lattice Distortions in the IR Reflection Spectra of Abrasion-Treated ZnSe Ceramics

NASA Astrophysics Data System (ADS)

Sitnikova, V. E.; Dunaev, A. A.; Mamalimov, R. I.; Pakhomov, P. M.; Khizhnyak, S. D.; Chmel, A. E.

2017-07-01

The Fourier IR reflection spectra of ZnSe ceramics prepared by hot pressing (HP), physical vapor deposition (PVD), and PVD combined with hot isostatic pressing (HIP) are presented. The optical constants of polished and dry-ground specimens were used for comparison. The grinding treatment simulated the erosion of the outer surface of optical elements made of zinc selenide under the influence of solid dust particles and deposits. In the polished specimens residual stresses showed up in the IR reflection spectra of the ZnSePVD and ZnSeHIP ceramics, which had well-defined orientation of grains, but were not present in the spectra of the ZnSeHIP ceramics as a result of mutual compensation of the stresses in the randomly oriented grains of the material. The stresses, which appeared as a shift of the absorption bands calculated by the Kramers-Kronig method, increased significantly after abrasive treatment of the specimens. For all the treated ceramics the intensity of the absorption bands resulting from the anharmonicity of the vibrations in the distorted crystal lattice increased by several times. The last effect also depends on the production prehistory of the ceramics.

Pulmonary Hypertension and Vascular Abnormalities in Bronchopulmonary Dysplasia

PubMed Central

Mourani, Peter M.; Abman, Steven H.

2015-01-01

Advances in the care of preterm infants have improved survival of infants born at earlier gestational ages. Yet, these infants remain at risk for the chronic lung disease of infancy, bronchopulmonary dysplasia (BPD), which results in prolonged need for supplemental oxygen, recurrent respiratory exacerbations, and exercise intolerance. Recent investigations have highlighted the important contribution of the developing pulmonary circulation to lung development, demonstrating that these infants are also at risk for pulmonary vascular disease (PVD), including pulmonary hypertension (PH) and pulmonary vascular abnormalities, which contributes significantly to morbidity and mortality. In the past few years, several epidemiological studies have delineated the incidence of PH in preterm infants and the impact on outcomes. However, these studies have also highlighted gaps in our understanding of PVD in BPD, including universally accepted definitions, approaches to diagnosis and treatment, and patient outcomes. Associated pulmonary vascular and cardiac abnormalities are increasingly recognized complications contributing to PH in these infants, but incidence of these lesions and degree of contribution to disease remains unknown. Therapeutic strategies for PVD in BPD are largely untested, but recent evidence presents the rationale for the approach to diagnosis and treatment of BPD infants with PH that can be evaluated in future studies. PMID:26593082

Importance of calcium and magnesium in water - water hardening

NASA Astrophysics Data System (ADS)

Barloková, D.; Ilavský, J.; Kapusta, O.; Šimko, V.

2017-10-01

Basic information about importance of calcium and magnesium in water, about their properties, effect to human health, problems what can cause under the lower (< 1 mmol/L) and higher (> 5 mmol/L) concentrations in water supply distribution systems, the most commonly used methods of water hardening are presented. The article contains the water hardening results carried out during the pilot plant experiments in WTP Hriňová and WTP Turček. For water hardening, treated water at the end of the process line, i.e., after coagulation, sedimentation and filtration, saturated with CO2 and filtrated through half-burnt dolomite material (PVD) was used. The results show that the filtration rate is 17.1 m/h in the case of WTP Hriňová and 15.2 m/h in the case of WTP Turček to achieve the recommended concentration of Ca and Mg in the treated water after the addition of CO2 and filtration through PVD. The longer the water contact time with PVD (depending on the CO2 content), the more water is enriched with magnesium, but the calcium concentration has not so much increased.

Sexual Assertiveness Mediates the Associations Between Partner Facilitative Responses and Sexual Outcomes in Women With Provoked Vestibulodynia.

PubMed

McNicoll, Gabrielle; Corsini-Munt, Serena; O Rosen, Natalie; McDuff, Pierre; Bergeron, Sophie

2017-10-03

Provoked vestibulodynia (PVD) is a recurrent idiopathic vulvo-vaginal pain associated with negative sexual and psychological consequences. Facilitative partner responses to pain are currently receiving empirical attention because they are positively associated with women's sexual outcomes. However, the mechanisms through which facilitative responses to pain are associated with these outcomes have not been examined. One potential mechanism is sexual assertiveness, which has been found to be associated with better sexual function and satisfaction in women with PVD. The present study examined whether women's sexual assertiveness mediated the association between women's perception of facilitative partner responses and women's sexual function and satisfaction. Women (N = 140) with PVD symptomatology completed self-reported questionnaires evaluating their perception of their partners' facilitative responses, and their own sexual assertiveness, sexual function, and sexual satisfaction. Dependent measures were sexual function measured by the Female Sexual Function Index and sexual satisfaction assessed by the Global Measure of Sexual Satisfaction Scale. Results indicated that women's higher sexual assertiveness mediated the association between their greater perceived facilitative partner responses and their improved sexual function and satisfaction. Findings suggest a potential mechanism through which partner responses may be associated with women's sexual outcomes.

Plasmonic colour generation

NASA Astrophysics Data System (ADS)

Kristensen, Anders; Yang, Joel K. W.; Bozhevolnyi, Sergey I.; Link, Stephan; Nordlander, Peter; Halas, Naomi J.; Mortensen, N. Asger

2017-01-01

Plasmonic colours are structural colours that emerge from resonant interactions between light and metallic nanostructures. The engineering of plasmonic colours is a promising, rapidly emerging research field that could have a large technological impact. We highlight basic properties of plasmonic colours and recent nanofabrication developments, comparing technology-performance indicators for traditional and nanophotonic colour technologies. The structures of interest include diffraction gratings, nanoaperture arrays, thin films, and multilayers and structures that support Mie resonances and whispering-gallery modes. We discuss plasmonic colour nanotechnology based on localized surface plasmon resonances, such as gap plasmons and hybridized disk-hole plasmons, which allow for colour printing with sub-diffraction resolution. We also address a range of fabrication approaches that enable large-area printing and nanoscale lithography compatible with complementary metal-oxide semiconductor technologies, including nanoimprint lithography and self-assembly. Finally, we review recent developments in dynamically reconfigurable plasmonic colours and in the laser-induced post-processing of plasmonic colour surfaces.

Luminescent hyperbolic metasurfaces

NASA Astrophysics Data System (ADS)

Smalley, J. S. T.; Vallini, F.; Montoya, S. A.; Ferrari, L.; Shahin, S.; Riley, C. T.; Kanté, B.; Fullerton, E. E.; Liu, Z.; Fainman, Y.

2017-01-01

When engineered on scales much smaller than the operating wavelength, metal-semiconductor nanostructures exhibit properties unobtainable in nature. Namely, a uniaxial optical metamaterial described by a hyperbolic dispersion relation can simultaneously behave as a reflective metal and an absorptive or emissive semiconductor for electromagnetic waves with orthogonal linear polarization states. Using an unconventional multilayer architecture, we demonstrate luminescent hyperbolic metasurfaces, wherein distributed semiconducting quantum wells display extreme absorption and emission polarization anisotropy. Through normally incident micro-photoluminescence measurements, we observe absorption anisotropies greater than a factor of 10 and degree-of-linear polarization of emission >0.9. We observe the modification of emission spectra and, by incorporating wavelength-scale gratings, show a controlled reduction of polarization anisotropy. We verify hyperbolic dispersion with numerical simulations that model the metasurface as a composite nanoscale structure and according to the effective medium approximation. Finally, we experimentally demonstrate >350% emission intensity enhancement relative to the bare semiconducting quantum wells.

Atomic force microscopy of adsorbed proteoglycan mimetic nanoparticles: Toward new glycocalyx-mimetic model surfaces.

PubMed

Hedayati, Mohammadhasan; Kipper, Matt J

2018-06-15

Blood vessels present a dense, non-uniform, polysaccharide-rich layer, called the endothelial glycocalyx. The polysaccharides in the glycocalyx include polyanionic glycosaminoglycans (GAGs). This polysaccharide-rich surface has excellent and unique blood compatibility. We report new methods for preparing and characterizing dense GAG surfaces that can serve as models of the vascular endothelial glycocalyx. The GAG-rich surfaces are prepared by adsorbing heparin or chondroitin sulfate-containing polyelectrolyte complex nanoparticles (PCNs) to chitosan-hyaluronan polyelectrolyte multilayers (PEMs). The surfaces are characterized by PeakForce tapping atomic force microscopy, both in air and in aqueous pH 7.4 buffer, and by PeakForce quantitative nanomechanics (PF-QNM) mode with high spatial resolution. These new surfaces provide access to heparin-rich or chondroitin sulfate-rich coatings that mimic both composition and nanoscale structural features of the vascular endothelial glycocalyx. Copyright © 2018. Published by Elsevier Ltd.

Colloids in food: ingredients, structure, and stability.

PubMed

Dickinson, Eric

2015-01-01

This article reviews progress in the field of food colloids with particular emphasis on advances in novel functional ingredients and nanoscale structuring. Specific aspects of ingredient development described here are the stabilization of bubbles and foams by the protein hydrophobin, the emulsifying characteristics of Maillard-type protein-polysaccharide conjugates, the structural and functional properties of protein fibrils, and the Pickering stabilization of dispersed droplets by food-grade nanoparticles and microparticles. Building on advances in the nanoscience of biological materials, the application of structural design principles to the fabrication of edible colloids is leading to progress in the fabrication of functional dispersed systems-multilayer interfaces, multiple emulsions, and gel-like emulsions. The associated physicochemical insight is contributing to our mechanistic understanding of oral processing and textural perception of food systems and to the development of colloid-based strategies to control delivery of nutrients during food digestion within the human gastrointestinal tract.

Attempting nanolocalization of all-optical switching through nano-holes in an Al-mask

NASA Astrophysics Data System (ADS)

Savoini, M.; Reid, A. H.; Wang, T.; Graves, C. E.; Hoffmann, M. C.; Liu, T.-M.; Tsukamoto, A.; Stöhr, J.; Dürr, H. A.; Kirilyuk, A.; Kimel, A. V.; Rasing, T.

2014-08-01

We investigate the light-induced magnetization reversal in samples of rare-earth transition metal alloys, where we aim to spatially confine the switched region at the nanoscale, with the help of nano-holes in an Al-mask covering the sample. First of all, an optimum multilayer structure is designed for the optimum absorption of the incident light. Next, using finite difference time domain simulations we investigate light penetration through nano-holes of different diameter. We find that the holes of 200 nm diameter combine an optimum transmittance with a localization better than λ/4. Further, we have manufactured samples with the help of focused ion beam milling of Al-capped TbCoFe layers. Finally, employing magnetization-sensitive X-ray holography techniques, we have investigated the magnetization reversal with extremely high resolution. The results show severe processing effects on the switching characteristics of the magnetic layers.

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

DOE PAGES

Tian, Cheng; Cordeiro, Marco Aurelio L.; Lhermitte, Julien; ...

2017-05-25

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. We report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization.more » Furthermore, by controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.« less

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

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

Tian, Cheng; Cordeiro, Marco Aurelio L.; Lhermitte, Julien

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. We report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization.more » Furthermore, by controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.« less

Supra-Nanoparticle Functional Assemblies through Programmable Stacking.

PubMed

Tian, Cheng; Cordeiro, Marco Aurelio L; Lhermitte, Julien; Xin, Huolin L; Shani, Lior; Liu, Mingzhao; Ma, Chunli; Yeshurun, Yosef; DiMarzio, Donald; Gang, Oleg

2017-07-25

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. Here, we report a general method of assembling nanoparticles in a linear "pillar" morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization. By controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.

Zero-dimensional to three-dimensional nanojoining: current status and potential applications

DOE PAGES

Ma, Ying; Li, Hong; Bridges, Denzel; ...

2016-08-01

We report that the continuing miniaturization of microelectronics is pushing advanced manufacturing into nanomanufacturing. Nanojoining is a bottom-up assembly technique that enables functional nanodevice fabrication with dissimilar nanoscopic building blocks and/or molecular components. Various conventional joining techniques have been modified and re-invented for joining nanomaterials. Our review surveys recent progress in nanojoining methods, as compared to conventional joining processes. Examples of nanojoining are given and classified by the dimensionality of the joining materials. At each classification, nanojoining is reviewed and discussed according to materials specialties, low dimensional processing features, energy input mechanisms and potential applications. The preparation of new intermetallicmore » materials by reactive nanoscale multilayer foils based on self-propagating high-temperature synthesis is highlighted. This review will provide insight into nanojoining fundamentals and innovative applications in power electronics packaging, plasmonic devices, nanosoldering for printable electronics, 3D printing and space manufacturing.« less

Recent Applications of Coaxial and Emulsion Electrospinning Methods in the Field of Tissue Engineering

PubMed Central

McClellan, Phillip; Landis, William J.

2016-01-01

Abstract Electrospinning has emerged as an effective method of producing nanoscale fibers for use in multiple fields of study. One area of significant interest is nanofiber utilization for tissue engineering because the nanofibrous mats can mimic the native extracellular matrix of biological tissues. A logical next step is the inclusion of certain molecules and compounds to accelerate or increase the efficacy of tissue regeneration. Two methods are under scrutiny for their capability to encapsulate therapeutic compounds within electrospun nanofibers: emulsion and coaxial electrospinning. Both have advantages and disadvantages, which need to be taken into careful consideration when deciding to use them in a specific application. Several examples are provided here to highlight the vast potential of multilayered nanofibers as well as the emergence of new techniques to produce three-dimensional scaffolds of nanofibers for use in the field of tissue engineering. PMID:27610268

Theoretical study on electronic properties of MoS{sub 2} antidot lattices

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

Shao, Li; Chen, Guangde; Ye, Honggang, E-mail: hgye@mail.xjtu.edu.cn

2014-09-21

Motivated by the state of the art method for etching hexagonal array holes in molybdenum disulfide (MoS{sub 2}), the electronic properties of MoS{sub 2} antidot lattices (MoS{sub 2}ALs) with zigzag edge were studied with first-principles calculations. Monolayer MoS{sub 2}ALs are semiconducting and the band gaps converge to constant values as the supercell area increases, which can be attributed to the edge effect. Multilayer MoS{sub 2}ALs and chemical adsorbed MoS{sub 2}ALs by F atoms show metallic behavior, while the structure adsorbed with H atoms remains to be semiconducting with a tiny bandgap. Our results show that forming periodically repeating structures inmore » MoS{sub 2} can develop a promising technique for engineering nano materials and offer new opportunities for designing MoS{sub 2}-based nanoscale electronic devices and chemical sensors.« less

Protection mechanisms of the iron-plated armor of a deep-sea hydrothermal vent gastropod

PubMed Central

Yao, Haimin; Dao, Ming; Imholt, Timothy; Huang, Jamie; Wheeler, Kevin; Bonilla, Alejandro; Suresh, Subra; Ortiz, Christine

2010-01-01

Biological exoskeletons, in particular those with unusually robust and multifunctional properties, hold enormous potential for the development of improved load-bearing and protective engineering materials. Here, we report new materials and mechanical design principles of the iron-plated multilayered structure of the natural armor of Crysomallon squamiferum, a recently discovered gastropod mollusc from the Kairei Indian hydrothermal vent field, which is unlike any other known natural or synthetic engineered armor. We have determined through nanoscale experiments and computational simulations of a predatory attack that the specific combination of different materials, microstructures, interfacial geometries, gradation, and layering are advantageous for penetration resistance, energy dissipation, mitigation of fracture and crack arrest, reduction of back deflections, and resistance to bending and tensile loads. The structure-property-performance relationships described are expected to be of technological interest for a variety of civilian and defense applications. PMID:20133823

Nanoscale control of oxide interface conduction in graphene-complex-oxide heterostructures

NASA Astrophysics Data System (ADS)

Huang, Mengchen; Ryu, Sangwoo; Ghahari, Fereshte; Jnawali, Giriraj; Ravichandran, Jayakanth; Irvin, Patrick; Kim, Philip; Eom, Chang-Beom; Levy, Jeremy

2014-03-01

Graphene is a promising material for high-speed optoelectronic devices such as THz modulators and detectors. Recently, broadband THz emission and detection can be achieved with nanostructures at the LaAlO3/SrTiO3 interface [2]. We have mechanically exfoliated single layer and multilayer graphene on top of 3.4 unit cell LaAlO3/SrTiO3 and successfully sketched nanowires in the 2DEG underneath graphene using conductive AFM lithgraphy [3]. Raman and AFM investigations confirm that the graphene quality and surface morphology remain unaltered by the writing process. These first experimental demonstrations of integrating graphene and LaAlO3/SrTiO3 are promising for future DC-THz photonic applications. We gratefully acknowledge support for this work from ONR (N00014-13-1-0806), NSF(DMR-1124131, DMR-1104191), and AFOSR (FA9550-12-1-0342).

Use of ECT in the presence of acute bilateral posterior vitreous detachmanet.

PubMed

Taye, Tesema; Dobranici, Letitia; Fisher, Mark; Cullum, Sarah

2018-04-01

We describe a case of acute bilateral posterior vitreous detachment (PVD) in a 71-year-old female, which developed during a course of electroconvulsive therapy (ECT) for treatment-resistant depression. The risks and benefits of continuing ECT were assessed and the patient completed the full course of 16 ECT treatments without further ophthalmic complications. As the incidence of PVD increases with age, and ECT is used more frequently in elderly people with depression, we recommend paying attention to ophthalmic symptoms as part of the routine clinical monitoring of ECT side effects. If ophthalmic symptoms occur, the risks and benefits of ECT need to be weighed up including consultation with an ophthalmologist.

Development of nanostructured PVD coatings for total knee replacement joints using HIPIMS

NASA Astrophysics Data System (ADS)

Sugumaran, Arunprabhu A.

The aim of this study was to develop thin film coatings for total knee replacement joints using high power impulse magnetron sputtering (HIPIMS). An industrial size four cathode magnetron sputtering system equipped with direct current (DC) and HIPIMS power supplies was used for this purpose. Initially, Plasma diagnostics were carried out using optical emission spectroscopy (OES) while sputtering Ti target in Ar + N2 atmosphere by utilizing various HIP IMS/conventional DCMS (henceforth UBM) source combinations by varying the process parameters such as coil current and N2 flow. Then, single layer titanium nitride (TiN) coating was deposited by varying the degree of HIPIMS utilisation and the process parameters such as bias voltage and coil current to thoroughly understand the effect of degree of HIPIMS utilisation on the microstructure, residual stress, texture, mechanical, tribological and corrosion properties of such coatings. The degree of HIPIMS utilisation was altered by increasing the number of HIPIMS targets used for the deposition. Four different source combinations were used for this purpose, as follows: 4 cathodes in conventional DCMS mode to deposit pure UBM coating, 1 HIPIMS + 3UBM and 2HIPIMS + 2UBM cathodes to deposit combined HIPIMS/UBM coatings and 2HIPIMS cathodes to deposit pure HIPIMS coatings. TiN/NbN, TiCN/NbCN and CrN/NbN multilayer coatings were deposited on CoCr alloy test buttons along with other (HSS, SS and Si) substrates since our intended application is on total knee replacement joints made of CoCr alloy. The knowledge gained by investigating the TiN (Ar + N[2]) plasma and the properties of TiN was used to determine the process parameters for depositing the multilayer coatings. X- ray diffraction (XRD) technique was used for calculating the texture, residual stress and bilayer thickness of the coatings. Nanoindentation method was used to determine the nano hardness of the coatings. The adhesion strength of the coatings was estimated by scratch and Rockwell indentation tests. Pin on disc method was used for the tribological studies such as coefficient of friction and coefficient of wear. Surface roughness measurements were carried out using a surface profiler. Microstructural characterisation of the coatings was carried out using scanning electron microscope (SEM) and transmission electron microscope (TEM). Potentiodynamic polarisation method was utilised to study the corrosion performance of the coatings. Raman spectroscopy was used to study the constituents of the corrosion products and evaluate the corrosion damage. OES measurements revealed that the degree of metal ions (Ti[1+]) increased with increasing degree of HIPIMS utilisation. The hardness, tribological and corrosion properties of TiN coatings improved with increasing degree of HIPIMS utilisation. TiN and multilayer coatings deposited by HIPIMS exhibited a smooth columnar microstructure without any voided region along the column boundaries. TiN/NbN, TiCN/NbCN and CrN/NbN multilayer coatings deposited on CoCr alloy, HSS and SS test buttons exhibited superior mechanical, tribological and corrosion properties as compared to the underlying substrate.

Synthesis and electrochemical properties of Ti-doped DLC films by a hybrid PVD/PECVD process

NASA Astrophysics Data System (ADS)

Jo, Yeong Ju; Zhang, Teng Fei; Son, Myoung Jun; Kim, Kwang Ho

2018-03-01

Low electrical conductivity and poor adhesion to metallic substrates are the main drawbacks of diamond-like carbon (DLC) films when used in electrode applications. In this study, Ti-doped DLC films with various Ti contents were synthesized on metal Ti substrates by a hybrid PVD/PECVD process, where PECVD was used for deposition of DLC films and PVD was used for Ti doping. The effects of the Ti doping ratio on the microstructure, adhesion strength, and electrical and electrochemical properties of the DLC films were systematically investigated. An increase in the Ti content led to increased surface roughness and a higher sp2/sp3 ratio of the Ti-DLC films. Ti atoms existed as amorphous-phase Ti carbide when the Ti doping ratio was less than 2.8 at.%, while the nanocrystalline TiC phase was formed in DLC films when the Ti doping ratio was exceeded 4.0 at.%. The adhesion strength, electrical resistivity, electrochemical activity and reversibility of the DLC films were greatly improved by Ti doping. The influence of Ti doping ratio on the electrical and electrochemical properties of the DLC films were also investigated and the best performance was obtained at a Ti content of 2.8 at.%.

Assessment of Cyclic Lifetime of NiCoCrAlY/ZrO2-Based EB-PVD TBC Systems via Reactive Element Enrichment in the Mixed Zone of the TGO Scale

NASA Astrophysics Data System (ADS)

Fritscher, Klaus; Braue, Wolfgang; Schulz, Uwe

2013-05-01

The chemical composition of the alumina-zirconia mixed zone (MZ) of an electron beam physical vapor deposited thermal barrier coating (EB-PVD TBC) system is affected by service conditions and by the interdiffusion of elements from the substrate alloy below and the zirconia top coat. Three NiCoCrAlY bond-coated Ni-base substrates with YPSZ or CeSZ EB-PVD TBCs were subjected to a cyclic furnace oxidation test (FCT) at 1373 K (1100 °C) in order to provide experimental evidence of a link between chemistry of the MZ, the substrate alloy, the ceramic top coat, and the time in the FCT. Energy dispersive spectroscopy of the MZ revealed preferred accumulation of Cr, Zr, Y, and Ce. The concentration of the reactive elements (RE = Ce + Y + Zr) was related to the respective average lifetimes of the TBC systems at 1373 K (1100 °C). The RE content in the MZ turned out to be a life-limiting parameter for YPSZ and CeSZ TBC systems which can be utilized to predict their relative lifetimes on the individual substrates. Conversely, the TBC failure mechanisms of YPSZ and CeSZ TBC systems are dissimilar.

Free vibration of an embedded single-walled carbon nanotube with various boundary conditions using the RMVT-based nonlocal Timoshenko beam theory and DQ method

NASA Astrophysics Data System (ADS)

Wu, Chih-Ping; Lai, Wei-Wen

2015-04-01

The nonlocal Timoshenko beam theories (TBTs), based on the Reissner mixed variation theory (RMVT) and principle of virtual displacement (PVD), are derived for the free vibration analysis of a single-walled carbon nanotube (SWCNT) embedded in an elastic medium and with various boundary conditions. The strong formulations of the nonlocal TBTs are derived using Hamilton's principle, in which Eringen's nonlocal constitutive relations are used to account for the small-scale effect. The interaction between the SWCNT and its surrounding elastic medium is simulated using the Winkler and Pasternak foundation models. The frequency parameters of the embedded SWCNT are obtained using the differential quadrature (DQ) method. In the cases of the SWCNT without foundations, the results of RMVT- and PVD-based nonlocal TBTs converge rapidly, and their convergent solutions closely agree with the exact ones available in the literature. Because the highest order with regard to the derivatives of the field variables used in the RMVT-based nonlocal TBT is lower than that used in its PVD-based counterpart, the former is more efficient than the latter with regard to the execution time. The former is thus both faster and obtains more accurate solutions than the latter for the numerical analysis of the embedded SWCNT.

Quasi-solid state electrolyte for semi-transparent bifacial dye-sensitized solar cell with over 10% power conversion efficiency

NASA Astrophysics Data System (ADS)

Hwang, Dae-Kue; Nam, Jung Eun; Jo, Hyo Jeong; Sung, Shi-Joon

2017-09-01

In traditional dye-sensitized solar cells (DSSCs), the liquid electrolyte (LE) presents a problem for long-term stability. Herein, we demonstrate a bifacial DSSC by combining a new metal-free organic dye and a quasi-solid state electrolyte (QSSE) that contains poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP)-based polymer gel. The incident light irradiates the front side of the DSSC, and the transmitted light is reused after reflection on the back side. Owing to the semi-transparent DSSC electrode, the reflected light can penetrate and be absorbed by the dye molecules in the DSSC, thereby enhancing the short-circuit current density and thus the overall power conversion efficiency (PCE). The PCE for the DSSC device with QSSE from bifacial irradiation is 10.37%, a value that is comparable to that obtained with LE-based DSSC (9.89%). The stability of the device is enhanced when the polymer gel containing PVdF-HFP is mixed with the LE, and the effectiveness of PVdF-HFP as a gelator is attributed to its interaction with the Li+ ions. Based on our preliminary results, this architecture can lead to more stable bifacial QSSE-based DSSCs without sacrificing the photovoltaic performance.

Adhesive force between graphene nanoscale flakes and living biological cells.

PubMed

Al Faouri, Radwan; Henry, Ralph; Biris, Alexandru S; Sleezer, Rob; Salamo, Gregory J

2017-11-01

We report on a measurement technique that quantifies the adhesive force between multi-layers of graphene flakes and the cell wall of live Escherichia coli cells using atomic force microscopy (AFM) in-fluid Peak Force- Quantitative Nanomechanical Mapping mode. To measure the adhesive force, we made use of the negative charge of E. coli cells to allow them to stick to positively charged surfaces, such as glass or silicon, that were covered by poly-L-Lysine. With this approach, cells were held in place for AFM characterization. Both pristine graphene (PG) flakes and functionalized graphene (FG) flakes were put on the E. coli cells and measurements of lateral size, flake thickness, and adhesion were made. Using this approach, the measured values of the adhesive force between multi-layers of graphene flakes (total thickness of 50 nm) and E. coli was determined to be equal or greater than 431 ± 65pN for (PG) and 694 ± 98pN for the (FG). More interestingly, the adhesive force of a graphene flake (thickness 1.3 nm) with the cell is determined to be equal or greater than 38.2 ± 16.4pN for the (PG) and 34.8 ± 15.3pN for the (FG). These interaction values can play an important role in determining and understanding the possible toxicity of graphene flakes. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Isolation, characterization and cloning of a cDNA encoding a new antifungal defensin from Phaseolus vulgaris L. seeds.

PubMed

Games, Patrícia D; Dos Santos, Izabela S; Mello, Erica O; Diz, Mariângela S S; Carvalho, André O; de Souza-Filho, Gonçalo A; Da Cunha, Maura; Vasconcelos, Ilka M; Ferreira, Beatriz Dos S; Gomes, Valdirene M

2008-12-01

The PvD1 defensin was purified from Phaseolus vulgaris (cv. Pérola) seeds, basically as described by Terras et al. [Terras FRG, Schoofs HME, De Bolle MFC, Van Leuven F, Ress SB, Vanderleyden J, Cammue BPA, Broekaer TWF. Analysis of two novel classes of plant antifungal proteins from radish (Raphanus sativus L.) seeds. J Biol Chem 1992;267(22):15301-9], with some modifications. A DEAE-Sepharose, equilibrated with 20mM Tris-HCl, pH 8.0, was initially utilized for the separation of peptides after ammonium sulfate fractionation. The basic fraction (the non-retained peak) obtained showed the presence of one unique band in SDS-Tricine gel electrophoresis with a molecular mass of approximately 6kDa. The purification of this peptide was confirmed after a reverse-phase chromatography in a C2/C18 column by HPLC, where once again only one peak was observed and denominated H1. H1 was submitted to N-terminal sequencing and the comparative analysis in databanks revealed high similarity with sequences of different defensins isolated from other plants species. The N-terminal sequence of the mature defensin isolated was used to produce a degenerated primer. This primer allowed the amplification of the defensin cDNA by RT-PCR from mRNA of P. vulgaris seeds. The sequence analysis of the cloned cDNA, named PVD1, demonstrated 314bp encoding a polypeptide of 47 amino acids. The deduced peptide presented high similarity with plant defensins of Vigna unguiculata (93%), Cicer arietinum (95%) and Pachyrhizus erosus (87%). PvD1 inhibited the growth of the yeasts, Candida albicans, Candida parapsilosis, Candida tropicalis, Candida guilliermondii, Kluyveromyces marxiannus and Saccharomyces cerevisiae. PvD1 also presented an inhibitory activity against the growth of phytopathogenic fungi including Fusarium oxysporum, Fusarium solani, Fusarium lateritium and Rizoctonia solani.

Advanced process control and novel test methods for PVD silicon and elastomeric silicone coatings utilized on ion implant disks, heatsinks and selected platens

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

Springer, J.; Allen, B.; Wriggins, W.

Coatings play multiple key roles in the proper functioning of mature and current ion implanters. Batch and serial implanters require strategic control of elemental and particulate contamination which often includes scrutiny of the silicon surface coatings encountering direct beam contact. Elastomeric Silicone Coatings must accommodate wafer loading and unloading as well as direct backside contact during implant plus must maintain rigid elemental and particulate specifications. The semiconductor industry has had a significant and continuous effort to obtain ultra-pure silicon coatings with sustained process performance and long life. Low particles and reduced elemental levels for silicon coatings are a major requirementmore » for process engineers, OEM manufacturers, and second source suppliers. Relevant data will be presented. Some emphasis and detail will be placed on the structure and characteristics of a relatively new PVD Silicon Coating process that is very dense and homogeneous. Wear rate under typical ion beam test conditions will be discussed. The PVD Silicon Coating that will be presented here is used on disk shields, wafer handling fingers/fences, exclusion zones of heat sinks, beam dumps and other beamline components. Older, legacy implanters can now provide extended process capability using this new generation PVD silicon - even on implanter systems that were shipped long before the advent of silicon coating for contamination control. Low particles and reduced elemental levels are critical performance criteria for the silicone elastomers used on disk heatsinks and serial implanter platens. Novel evaluation techniques and custom engineered tools are used to investigate the surface interaction characteristics of multiple Elastomeric Silicone Coatings currently in use by the industry - specifically, friction and perpendicular stiction. These parameters are presented as methods to investigate the critical wafer load and unload function. Unique tools and test methods have been developed that deliver accurate and repeatable data, which will be described.« less

Advanced process control and novel test methods for PVD silicon and elastomeric silicone coatings utilized on ion implant disks, heatsinks and selected platens

NASA Astrophysics Data System (ADS)

Springer, J.; Allen, B.; Wriggins, W.; Kuzbyt, R.; Sinclair, R.

2012-11-01

Coatings play multiple key roles in the proper functioning of mature and current ion implanters. Batch and serial implanters require strategic control of elemental and particulate contamination which often includes scrutiny of the silicon surface coatings encountering direct beam contact. Elastomeric Silicone Coatings must accommodate wafer loading and unloading as well as direct backside contact during implant plus must maintain rigid elemental and particulate specifications. The semiconductor industry has had a significant and continuous effort to obtain ultra-pure silicon coatings with sustained process performance and long life. Low particles and reduced elemental levels for silicon coatings are a major requirement for process engineers, OEM manufacturers, and second source suppliers. Relevant data will be presented. Some emphasis and detail will be placed on the structure and characteristics of a relatively new PVD Silicon Coating process that is very dense and homogeneous. Wear rate under typical ion beam test conditions will be discussed. The PVD Silicon Coating that will be presented here is used on disk shields, wafer handling fingers/fences, exclusion zones of heat sinks, beam dumps and other beamline components. Older, legacy implanters can now provide extended process capability using this new generation PVD silicon - even on implanter systems that were shipped long before the advent of silicon coating for contamination control. Low particles and reduced elemental levels are critical performance criteria for the silicone elastomers used on disk heatsinks and serial implanter platens. Novel evaluation techniques and custom engineered tools are used to investigate the surface interaction characteristics of multiple Elastomeric Silicone Coatings currently in use by the industry - specifically, friction and perpendicular stiction. These parameters are presented as methods to investigate the critical wafer load and unload function. Unique tools and test methods have been developed that deliver accurate and repeatable data, which will be described.

Functional mechanism of lung mosaic CT attenuation: assessment with deep-inspiration breath-hold perfusion SPECT-CT fusion imaging and non-breath-hold Technegas SPECT.

PubMed

Suga, K; Yasuhiko, K; Iwanaga, H; Tokuda, O; Matsunaga, N

2009-01-01

The functional mechanism of lung mosaic computed tomography attenuation (MCA) in pulmonary vascular disease (PVD) and obstructive airway disease (OAD) has not yet been fully clarified. To clarify the mechanism of MCA in these diseases by assessing the relationship between regional lung function and CT attenuation change at MCA sites with the use of automated deep-inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images and non-breath-hold Technegas SPECT. Subjects were 42 PVD patients (31 pulmonary thromboembolism, four primary/two secondary pulmonary hypertension, and five Takayasu arteritis), 12 OAD patients (five acute asthma, four obliterative bronchiolitis, and three bronchiectasis), and 12 normal controls, all of whom had MCA on DIBrH CT. The relationship between regional lung function and CT attenuation change at the lung slices with MCA was assessed using DIBrH perfusion SPECT-CT fusion images and non-breath-hold Technegas SPECT. The severity of perfusion defects with or without MCA was quantified by regions-of-interest analysis. On DIBrH CT and perfusion SPECT, in contrast to no noticeable CT attenuation abnormality and fairly uniform perfusion in controls, 60 MCA and 274 perfusion defects in PVD patients, and 18 MCA and 61 defects in OAD patients were identified, with a total of 77 ventilation defects on Technegas SPECT in all patients. SPECT-CT correlation showed that, throughout the 78 MCA sites of all patients, lung perfusion was persistently decreased at low CT attenuation and preserved at intervening high CT attenuation, while lung ventilation was poorly correlated with CT attenuation change. The radioactivity ratios of reduced perfusion and the intervening preserved perfusion at the 78 perfusion defects with MCA were significantly lower than those at the remaining 257 defects without MCA (P<0.0001). Although further validation is required, our results indicate that heterogeneous pulmonary arterial perfusion may be a dominant mechanism of MCA in PVD and OAD.

The ACTIV study: acupuncture treatment in provoked vestibulodynia.

PubMed

Curran, Stephanie; Brotto, Lori A; Fisher, Harris; Knudson, Gail; Cohen, Trevor

2010-02-01

Provoked vestibulodynia (PVD) is a distressing genital pain condition affecting 12% of women. Treatment modalities vary and although vestibulectomy has the highest efficacy rates, it is usually not a first-line option. Acupuncture has a long history in the traditional Chinese medicine (TCM) system and operates on the premise that pain results from the blockage or imbalance of important channels. The main principle of treatment is to move Qi and blood to cease genital pain. To explore effect sizes and feasibility in a pilot study of acupuncture for women with PVD. Eight women with PVD (mean age 30 years) underwent 10 1-hour acupuncture sessions. Specific placement of the needles depended on the woman's individual TCM diagnosis. TCM practitioners made qualitative notes on participants' feedback after each session. Main Outcome Measures. Self-reported pain (investigator-developed), pain-associated cognitions (Pain Catastrophizing Scale [PCS], Pain Vigilance and Awareness Questionnaire), and sexual response (Female Sexual Function Index) were measured before and after treatment sessions 5 and 10. Qualitative analyses of TCM practitioner notes were performed along with one in-depth case report on the experience of a participant. A repeated measures analysis of variance revealed significant decreases in pain with manual genital stimulation and helplessness on the PCS. An examination of effect sizes also revealed strong (though nonsignificant) effects for improved ability to have intercourse and sexual desire. Qualitative analyses were overall more positive and revealed an improvement in perceived sexual health, reduced pain, and improved mental well-being in the majority of participants. Effect sizes and qualitative analyses of practitioner-initiated interviews showed overall positive effects of acupuncture, but there were statistically significant improvements only in pain with manual genital stimulation and helplessness. These findings require replication in a larger, controlled trial before any definitive conclusions on the efficacy of acupuncture for PVD can be made.

Systematic Review of the Effectiveness of Physical Therapy Modalities in Women With Provoked Vestibulodynia.

PubMed

Morin, Mélanie; Carroll, Marie-Soleil; Bergeron, Sophie

2017-07-01

Pelvic floor muscle physical therapy is recommended in clinical guidelines for women with provoked vestibulodynia (PVD). Including isolated or combined treatment modalities, physical therapy is viewed as an effective first-line intervention, yet no systematic review concerning the effectiveness of physical therapy has been conducted. To systematically appraise the current literature on the effectiveness of physical therapy modalities for decreasing pain during intercourse and improving sexual function in women with PVD. A systematic literature search using PubMed, Scopus, CINHAL, and PEDro was conducted until October 2016. Moreover, a manual search from reference lists of included articles was performed. Ongoing trials also were reviewed using clinicaltrial.gov and ISRCTNregistry. Randomized controlled trials, prospective and retrospective cohorts, and case reports evaluating the effect of isolated or combined physical therapy modalities in women with PVD were included in the review. Main outcome measures were pain during intercourse, sexual function, and patient's perceived improvement. The literature search resulted in 43 eligible studies including 7 randomized controlled trials, 20 prospective studies, 5 retrospective studies, 6 case reports, and 6 study protocols. Most studies had a high risk of bias mainly associated with the lack of a comparison group. Another common bias was related to insufficient sample size, non-validated outcomes, non-standardized intervention, and use of other ongoing treatment. The vast majority of studies showed that physical therapy modalities such as biofeedback, dilators, electrical stimulation, education, multimodal physical therapy, and multidisciplinary approaches were effective for decreasing pain during intercourse and improving sexual function. The positive findings for the effectiveness of physical therapy modalities in women with PVD should be investigated further in robust and well-designed randomized controlled trials. Morin M, Carroll M-S, Bergeron S. Systematic Review of the Effectiveness of Physical Therapy Modalities in Women With Provoked Vestibulodynia. Sex Med Rev 2017;5:295-322. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Low intrinsic c-axis thermal conductivity in PVD grown epitaxial Sb2Te3 films

NASA Astrophysics Data System (ADS)

Rieger, F.; Kaiser, K.; Bendt, G.; Roddatis, V.; Thiessen, P.; Schulz, S.; Jooss, C.

2018-05-01

Accurate determination and comprehensive understanding of the intrinsic c-axis thermal conductivity κc of thermoelectric layered Sb2Te3 is of high importance for the development of strategies to optimize the figure of merit in thin film devices via heterostructures and defect engineering. We present here high precision measurements of κc of epitaxial Sb2Te3 thin films on Al2O3 substrates grown by physical vapor deposition in the temperature range of 100 K to 300 K. The Kapitza resistances of the involved interfaces have been determined and subtracted from the film data, allowing access to the intrinsic thermal conductivity of single crystalline Sb2Te3. At room temperature, we obtain κc = 1.9 W/m K, being much smaller than the in-plane thermal conductivity of κa b = 5 W/m K and even lower than the thermal conductivity of nano crystalline films of κnc ≈ 2.0-2.6 W/m K published by Park et al. [Nanoscale Res. Lett. 9, 96 (2014)]. High crystallinity and very low defect concentration of the films were confirmed by x-ray diffraction and high resolution transmission electron microscopy. Our data reveal that the phonon mean free path lm f p(" separators="|T ) is not limited by defect scattering and is of intrinsic nature, i.e., due to phonon-phonon scattering similar to other soft van der Waals type bonded layered systems.

Electrical and dielectric properties of PVdF-HFP - PMMA - (PC + DEC)- LiClO4 based gel polymer electrolyte

NASA Astrophysics Data System (ADS)

Gohel, Khushbu; Kanchan, D. K.; Maheshwaran, C.

2018-04-01

In the present paper, AC impedance studies have been measured to evaluate ion conduction behavior of (PVdF-HFP - PMMA) + (PC-DEC) + LiClO4 gel polymer electrolyte system prepared by solution casting method. Structural characterization and morphology has been carried out using XRD and SEM respectively. The AC conductivity and dielectric permittivity, electric modulus and relaxation mechanism have been studied. The variation of ac conductivity with frequency obeys Jonscher power law. Maximum value of dielectric constant ɛ' in the lower frequency region has been observed for the gel polymer electrolyte containing 7.5 wt% LiClO4. The highest conducting sample shows the shortest relaxation time.

TiO2 as conductivity enhancer in PVdF-HFP polymer electrolyte system

NASA Astrophysics Data System (ADS)

Bhattacharya, Shreya; Manojkumar Ubarhande, Radha; Usha Rani, M.; Shanker Babu, Ravi; Arunkumar, R.

2017-11-01

Composite polymer electrolytes were prepared by incorporating inorganic filler TiO2 into PVdF-HFP-PMMA-EC-LiClO4 system. The electrolyte films were prepared by solvent casting technique. The effect of inorganic filler on the conductivity of the blended polymer electrolyte was studied and it is found that there is a considerable increase in ionic conductivity 1.296 × 10-3 S/cm-1 on the addition of TiO2. X-ray diffraction (XRD) study elucidate the increase in amorphous nature of the polymer electrolyte. This tendency of the polymer electrolyte could be the reason behind the increase in ionic conductivity. Fourier transform infrared spectroscopy (FTIR) spectra show the occurrence of complexation and interaction among the components.

Metallic biomaterials TiN-coated: corrosion analysis and biocompatibility.

PubMed

Paschoal, André Luís; Vanâncio, Everaldo Carlos; Canale, Lauralice de Campos Franceschini; da Silva, Orivaldo Lopes; Huerta-Vilca, Domingos; Motheo, Artur de Jesus

2003-05-01

Corrosion processes due to contact with the physiological environment should be avoided or minimized in orthopedic implants. Four metallic substrates frequently used as biomaterials: pure Ti, Ti-6Al-4V alloy, ASTM F138 stainless steel, and Co-Cr-Mo alloy, were coated with TiN using the physical vapor deposition (PVD) technique. These coatings have been screened by polarization curves in physiological solutions. TiN prepared by PVD is efficient as coating for stainless steel. On titanium and alloy there are no benefits concerning the corrosion resistance compared to the bare Ti-materials. TiN coatings have been screened according to ISO 10993 standard tests for biocompatibility and exhibited no cytotoxicity, dermal irritation, or acute systemic toxicity response.

Vapor Deposition Rig

NASA Image and Video Library

2015-01-27

The Plasma Spray-Physical Vapor Deposition (PS-PVD) Rig at NASA Glenn Research Center. The rig helps develop coatings for next-generation aircraft turbine components and create more efficient engines.

Small-Gauge Pars Plana Vitrectomy for the Management of Symptomatic Posterior Vitreous Detachment after Phacoemulsification and Multifocal Intraocular Lens Implantation: A Pilot Study from the Pan-American Collaborative Retina Study Group

PubMed Central

Navarro, Rodrigo M.; Machado, Leonardo M.; Maia, Ossires; Wu, Lihteh; Farah, Michel E.; Magalhaes, Octaviano; Arevalo, J. Fernando; Maia, Mauricio

2015-01-01

Purpose. To determine the efficacy of 23-gauge pars plana vitrectomy (PPV) for symptomatic posterior vitreous detachment (PVD) on visual acuity (VA) and quality after multifocal intraocular lenses (IOLs). Methods. In this prospective case series, patients who developed symptomatic PVD and were not satisfied with visual quality due to floaters and halos after multifocal IOL implantation underwent PPV. Examinations included LogMAR uncorrected visual acuity (UCVA), intraocular pressure, biomicroscopy, and indirect ophthalmoscopy at baseline and 1, 7, 30, and 180 days postoperatively. Ultrasonography and aberrometry were performed. The Visual Functioning Questionnaire 25 (VFQ-25) was administered preoperatively and at 30 days postoperatively. Both the postoperative UCVA and questionnaire results were compared to preoperative findings using the Wilcoxon test. Results. Sixteen eyes of 8 patients were included. VA significantly improved from 0.17 to 0.09 postoperatively (P = 0.017). All patients reported improvement of halos, glare, and floaters. VFQ-25 scores significantly improved in general vision (P = 0.023), near activities (P = 0.043), distance activities (P = 0.041), mental health (P = 0.011), role difficulties (P = 0.042), and driving (P = 0.016). Conclusion. PPV may increase UCVA and quality of vision in patients with bilateral multifocal IOLs and symptomatic PVD. Larger studies are advised. PMID:26504590

Quantitative contrast enhanced magnetic resonance imaging for the evaluation of peripheral arterial disease: a comparative study versus standard digital angiography.

PubMed

Pavlovic, Chris; Futamatsu, Hideki; Angiolillo, Dominick J; Guzman, Luis A; Wilke, Norbert; Siragusa, Daniel; Wludyka, Peter; Percy, Robert; Northrup, Martin; Bass, Theodore A; Costa, Marco A

2007-04-01

The purpose of this study is to evaluate the accuracy of semiautomated analysis of contrast enhanced magnetic resonance angiography (MRA) in patients who have undergone standard angiographic evaluation for peripheral vascular disease (PVD). Magnetic resonance angiography is an important tool for evaluating PVD. Although this technique is both safe and noninvasive, the accuracy and reproducibility of quantitative measurements of disease severity using MRA in the clinical setting have not been fully investigated. 43 lesions in 13 patients who underwent both MRA and digital subtraction angiography (DSA) of iliac and common femoral arteries within 6 months were analyzed using quantitative magnetic resonance angiography (QMRA) and quantitative vascular analysis (QVA). Analysis was repeated by a second operator and by the same operator in approximately 1 month time. QMRA underestimated percent diameter stenosis (%DS) compared to measurements made with QVA by 2.47%. Limits of agreement between the two methods were +/- 9.14%. Interobserver variability in measurements of %DS were +/- 12.58% for QMRA and +/- 10.04% for QVA. Intraobserver variability of %DS for QMRA was +/- 4.6% and for QVA was +/- 8.46%. QMRA displays a high level of agreement to QVA when used to determine stenosis severity in iliac and common femoral arteries. Similar levels of interobserver and intraobserver variability are present with each method. Overall, QMRA represents a useful method to quantify severity of PVD.

Chronic subjective dizziness: Analysis of underlying personality factors.

PubMed

Chiarella, G; Petrolo, C; Riccelli, R; Giofrè, L; Olivadese, G; Gioacchini, F M; Scarpa, A; Cassandro, E; Passamonti, L

2016-11-03

Chronic subjective dizziness (CSD) is characterized by persistent dizziness, unsteadiness, and hypersensitivity to one's own motion or exposure to complex visual stimuli. CSD may be triggered, in predisposed individuals with specific personality traits, by acute vestibular diseases. CSD is also thought to arise from failure to re-establish normal balance strategies after resolution of acute vestibular events which may be modulated by diathesis to develop anxiety and depression. To confirm the role of personality traits linked to anxiety and depression (i.e., neuroticism, introversion, low openness) as predisposing factors for CSD and to evaluate how individual differences in these personality traits are associated with CSD severity. We compared 19 CSD patients with 24 individuals who had suffered from periferal vestibular disorders (PVD) (i.e., Benign Paroxysmal Postural Vertigo or Vestibular Neuritis) but had not developed CSD as well as with 25 healthy controls (HC) in terms of personality traits, assessed via the NEO-PI-R questionnaire. CSD patients, relative to PVD patients and HCs, scored higher on the anxiety facet of neuroticism. Total neuroticism scores were also significantly associated with dizziness severity in CSD patients but not PVD patients. Pre-existing anxiety-related personality traits may promote and sustain the initial etiophatogenetic mechanisms linked with the development of CSD. Targeting anxiety-related mechanisms in CSD may be therefore a promising way to reduce the disability associated with CSD.

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

Jayaraman, R.; Vickraman, P., E-mail: vrsvickraman@yahoo.com; Subramanian, N. M. V.

Impedance, XRD, DSC and FTIR studies had been carried out for PVdF-co-HFP/LIBETI based system for three plasticizer (EC/DMC) – filler (PbTiO3) weight ratios. The enhanced conductivity 4.18 × 10{sup −5} Scm{sup −1} was noted for 57.5 wt% −7.5 wt% plasticizer – filler. while blending PEMA to PVdF-co-HFP respectively 7.5: 22.5 wt % (3/7), 15 wt%: 15 wt % (5/5) and 22.5wt %: 7.5 wt % (7/3), the improved conductivity was noted for 3/7 ratio 1.22 × 10{sup −5} S cm{sup −1} and its temperature dependence abide Arrhenius behavior. The intensity of peaks in XRD diffractogram registered dominance of lead titanate,more » from 2θ = 10° to 80° and absence of VdF crystallites (α+β phase) was noted. In DSC studies, the presence of the exotherm events, filler effect was distinctively seen exhibiting recrystallization of VdF crystallites. In blending PEMA, however, no trace of exotherms was found suggestive of PEMA better inhibiting recrystallization. FTIR study confirmed molecular interactions of various constituents in the vibrational band 500 – 1000 cm{sup −1} both in pristine PVdF-co-HFP and PEMA blended composites with reference to C-F stretching, C-H stretching and C=O carbonyl bands.« less

Experimental and numerical investigations on the temperature distribution in PVD AlTiN coated and uncoated Al2O3/TiCN mixed ceramic cutting tools in hard turning of AISI 52100 steel

NASA Astrophysics Data System (ADS)

Sateesh Kumar, Ch; Patel, Saroj Kumar; Das, Anshuman

2018-03-01

Temperature generation in cutting tools is one of the major causes of tool failure especially during hard machining where machining forces are quite high resulting in elevated temperatures. Thus, the present work investigates the temperature generation during hard machining of AISI 52100 steel (62 HRC hardness) with uncoated and PVD AlTiN coated Al2O3/TiCN mixed ceramic cutting tools. The experiments were performed on a heavy duty lathe machine with both coated and uncoated cutting tools under dry cutting environment. The temperature of the cutting zone was measured using an infrared thermometer and a finite element model has been adopted to predict the temperature distribution in cutting tools during machining for comparative assessment with the measured temperature. The experimental and numerical results revealed a significant reduction of cutting zone temperature during machining with PVD AlTiN coated cutting tools when compared to uncoated cutting tools during each experimental run. The main reason for decrease in temperature for AlTiN coated tools is the lower coefficient of friction offered by the coating material which allows the free flow of the chips on the rake surface when compared with uncoated cutting tools. Further, the superior wear behaviour of AlTiN coating resulted in reduction of cutting temperature.

Gallium incorporation into phosphate based glasses: Bulk and thin film properties.

PubMed

Stuart, Bryan W; Grant, Colin A; Stan, George E; Popa, Adrian C; Titman, Jeremy J; Grant, David M

2018-06-01

The osteogenic ions Ca 2+ , P 5+ , Mg 2+ , and antimicrobial ion Ga 3+ were homogenously dispersed into a 1.45 µm thick phosphate glass coating by plasma assisted sputtering onto commercially pure grade titanium. The objective was to deliver therapeutic ions in orthopaedic/dental implants such as cementeless endoprostheses or dental screws. The hardness 4.7 GPa and elastic modulus 69.7 GPa, of the coating were comparable to plasma sprayed hydroxyapatite/dental enamel, whilst superseding femoral cortical bone. To investigate the manufacturing challenge of translation from a target to vapour condensed coating, structural/compositional properties of the target (P51MQ) were compared to the coating (P40PVD) and a melt-quenched equivalent (P40MQ). Following condensation from P51MQ to P40PVD, P 2 O 5 content reduced from 48.9 to 40.5 mol%. This depolymerisation and reduction in the P-O-P bridging oxygen content as determined by 31 P NMR, FTIR and Raman spectroscopy techniques was attributed to a decrease in the P 2 O 5 network former and increases in alkali/alkali-earth cations. P40PVD appeared denser (3.47 vs. 2.70 g cm -3 ) and more polymerised than it's compositionally equivalent P40MQ, showing that structure/ mechanical properties were affected by manufacturing route. Copyright © 2018. Published by Elsevier Ltd.

Psychosocial risk factors which may differentiate between women with Functional Voice Disorder, Organic Voice Disorder and a Control group.

PubMed

Baker, Janet; Ben-Tovim, David; Butcher, Andrew; Esterman, Adrian; McLaughlin, Kristin

2013-12-01

This study aimed to explore psychosocial factors contributing to the development of functional voice disorders (FVD) and those differentiating between organic voice disorders (OVD) and a non-voice-disordered control group. A case-control study was undertaken of 194 women aged 18-80 years diagnosed with FVD (n = 73), OVD (n = 55), and controls (n = 66). FVD women were allocated into psychogenic voice disorder (PVD) (n = 37) and muscle tension voice disorder (MTVD) (n = 36) for sub-group analysis. Dependent variables included biographical and voice assessment data, the number and severity of life events and difficulties and conflict over speaking out (COSO) situations derived from the Life Events and Difficulties Schedule (LEDS), and psychological traits including emotional expressiveness scales. Four psychosocial components differentiated between the FVD and control group accounting for 84.9% of the variance: severe events, moderate events, severe COSO, and mild COSO difficulties. Severe events, severe and mild COSO difficulties differentiated between FVD and OVD groups, accounting for 80.5% of the variance. Moderate events differentiated between PVD and MTVD sub-groups, accounting for 58.9% of the variance. Psychological traits did not differentiate between groups. Stressful life events and COSO situations best differentiated FVD from OVD and control groups. More refined aetiological studies are needed to differentiate between PVD and MTVD.

Physical vapor deposition of one-dimensional nanoparticle arrays on graphite: seeding the electrodeposition of gold nanowires.

PubMed

Cross, C E; Hemminger, J C; Penner, R M

2007-09-25

One-dimensional (1D) ensembles of 2-15 nm diameter gold nanoparticles were prepared using physical vapor deposition (PVD) on highly oriented pyrolytic graphite (HOPG) basal plane surfaces. These 1D Au nanoparticle ensembles (NPEs) were prepared by depositing gold (0.2-0.6 nm/s) at an equivalent thickness of 3-4 nm onto HOPG surfaces at 670-690 K. Under these conditions, vapor-deposited gold nucleated selectively at the linear step edge defects present on these HOPG surfaces with virtually no nucleation of gold particles on terraces. The number density of 2-15 nm diameter gold particles at step edges was 30-40 microm-1. These 1D NPEs were up to a millimeter in length and organized into parallel arrays on the HOPG surface, following the organization of step edges. Surprisingly, the deposition of more gold by PVD did not lead to the formation of continuous gold nanowires at step edges under the range of sample temperature or deposition flux we have investigated. Instead, these 1D Au NPEs were used as nucleation templates for the preparation by electrodeposition of gold nanowires. The electrodeposition of gold occurred selectively on PVD gold nanoparticles over the potential range from 700-640 mV vs SCE, and after optimization of the electrodeposition parameters continuous gold nanowires as small as 80-90 nm in diameter and several micrometers in length were obtained.

Gender Linked Metric Analysis of Portal Vein: A Sonographic Appraisal.

PubMed

Singh, Shikha; Pankaj, Arvind Kumar; Rani, Anita; Sharma, Pradeep Kumar; Chauhan, Puja

2017-03-01

Portal hypertension is one of the most mystifying and disconcerting abdominal ailment. Ultrasonography (USG) is an effective diagnostic tool for its prompt management. Knowledge of normal calibre of portal vein in a local setting is essential as literature reports contrasting values in different regions. It helps in early diagnosis of portal hypertension even before it is clinically manifested thereby assisting clinicians and interventional radiologists in pertinent management. Study was aimed to evaluate the Portal Vein Diameter (PVD) and find its correlation with gender by using USG in North Indian population. A total of 300 healthy adults were included in the study. Portal vein diameter was measured in supine position and normal respiration by grey scale USG. The portal vein diameter was correlated with age and gender statistically using independent Student's t-test and ANOVA. Mean PVD of (9.49±1.03 mm) was observed in the present cross-sectional study. Male showed a significantly higher mean PVD (9.70±1.02 mm) as compared to females (9.10±0.94 mm). Scarcity of information concerning ultrasonographically measured standard portal vein diameter and inconstant values reported in literature necessitates the need for establishing local standard value. In the given subset of population the portal vein diameter was influenced by the gender. The information will be helpful in prompt diagnosis and management of portal hypertension.

Observation of neovascularization of the disc associated with proliferative diabetic retinopathy using OCT angiography.

PubMed

Akiyama, Hideo; Li, Danjie; Shimoda, Yukitoshi; Matsumoto, Hidetaka; Kishi, Shoji

2018-05-01

To describe the relationship between the vitreous and the neovascularization of the disc (NVD) using swept source optical coherence tomography (SS-OCT) and OCT angiography (OCTA). Retrospective. We examined 17 eyes of 11 consecutive patients diagnosed as NVD associated with proliferative diabetic retinopathy (PDR). The location of the NVD feeder or collector vessels were examined by using RTVue XR Avanti. To determine the condition of the posterior vitreous detachment (PVD) and the proliferative tissue of the NVD, we performed 12 mm horizontal and vertical scans through the disc using SS-OCT. OCT images of all 17 cases indicated there was no PVD on the optic disc. OCTA showed that the locations of the newly formed vessels from the optic disc were overwhelmingly outside the physiological cupping (95%). No cases exhibited formation of neovascularization inside the physiological cupping. OCT images revealed all 17 eyes had proliferative tissues located under the posterior wall of the vitreous, with 12 out of 17 eyes exhibiting additional invasion of the proliferative tissue into the vitreous through the posterior wall. Epiretinal membrane or a thickened posterior wall of the vitreous was present in 10 out of the 17 eyes. NVD associated with PDR arises from outside the physiological cupping and grows along the posterior wall of the vitreous. The absence of PVD on the optic disc is essential to the growth of NVD.

Studies on the effect of dispersoid(ZrO2) in PVdF-co-HFP based gel polymer electrolytes

NASA Astrophysics Data System (ADS)

Sivakumar, M.; Subadevi, R.; Muthupradeepa, R.

2013-06-01

Gel polymer electrolytes containing poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) / Lithium bis(trifluoromethane sulfon)imide (LiTFSI) / mixture of ethylene carbonate and propylene carbonate (EC+PC) with different concendration of ZrO2 has been prepared using the solution casting technique. The conductivity of the prepared electrolyte sample has been determined by AC impedance technique in the range 303-353K. The temperature dependent ionic conductivity plot seems to obey VTF relation. The maximum ionic conductivity value of 4.46 × 10-3S/cm has been obtained for PVdF-co-HFP(32%) - LiTFSI(8%) - EC+PC (60%) + ZrO2(6wt%) based polymer electrolyte. The surface morphology of the prepared electrolyte sample has been studied using SEM.

Fabricating and strengthening the carbon nanotube/copper composite fibers with high strength and high electrical conductivity

NASA Astrophysics Data System (ADS)

Han, Baoshuai; Guo, Enyu; Xue, Xiang; Zhao, Zhiyong; Li, Tiejun; Xu, Yanjin; Luo, Liangshun; Hou, Hongliang

2018-05-01

Combining the excellent properties of carbon nanotube (CNT) and copper, CNT/Cu composite fibers were fabricated by physical vapor deposition (PVD) and rolling treatment. Dense and continuous copper film (∼2 μm) was coated on the surface of the CNT fibers by PVD, and rolling treatment was adopt to strengthen the CNT/Cu composite fibers. After the rolling treatment, the defects between the Cu grains and the CNT bundles were eliminated, and the structure of both the copper film and the core CNT fibers were optimized. The rolled CNT/Cu composite fibers possess high tensile effective strength (1.01 ± 0.13 GPa) and high electrical conductivity ((2.6 ± 0.3) × 107 S/m), and thus, this material may become a promising wire material.

Design of multifunctional nanoparticles for combined in-vivo imaging and advanced drug delivery

NASA Astrophysics Data System (ADS)

Leary, James F.

2018-02-01

Design of multifunctional nanoparticles for multimodal in-vivo imaging and advanced targeting to diseased single cells for massive parallel processing nanomedicine approaches requires careful overall design and a multilayered approach. Initial core materials can include non-toxic metals which not only serve as an x-ray contrast agent for CAT scan imaging, but can contain T1 or T2 contrast agents for MRI imaging. One choice is superparamagnetic iron oxide NPs which also allow for convenient magnetic manipulation during manufacturing but also for re-positioning inside the body and for single cell hyperthermia therapies. To permit real-time fluorescence-guided surgery, fluorescence molecules can be included. Advanced targeting can be achieved by attaching antibodies, peptides, aptamers, or other targeting molecules to the nanoparticle in a multilayered approach producing "programmable nanoparticles" whereby the "programming" means controlling a sequence of multi-step targeting methods. Addition of membrane permeating peptides can facilitate uptake by the cell. Addition of "stealth" molecules (e.g. PEG or chitosan) to the outer surfaces of the nanoparticles can permit greatly enhanced circulation times in-vivo which in turn lead to lower amounts of drug exposure to the patient which can reduce undesirable side effects. Nanoparticles with incomplete layers can be removed by affinity purification methods to minimize mistargeting events in-vivo. Nanoscale imaging of these manufactured, multifunctional nanoparticles can be achieved either directly through superresolution microscopy or indirectly through single nanoparticle zeta-sizing or x-ray correlation microscopy. Since these multifunctional nanoparticles are best analyzed by technologies permitting analysis in aqueous environments, superresolution microscopy is, in most cases, the preferred method.

Nanoscale reduction of graphene oxide thin films and its characterization

NASA Astrophysics Data System (ADS)

Lorenzoni, M.; Giugni, A.; Di Fabrizio, E.; Pérez-Murano, Francesc; Mescola, A.; Torre, B.

2015-07-01

In this paper, we report on a method to reduce thin films of graphene oxide (GO) to a spatial resolution better than 100 nm over several tens of micrometers by means of an electrochemical scanning probe based lithography. In situ tip-current measurements show that an edged drop in electrical resistance characterizes the reduced areas, and that the reduction process is, to a good approximation, proportional to the applied bias between the onset voltage and the saturation thresholds. An atomic force microscope (AFM) quantifies the drop of the surface height for the reduced profile due to the loss of oxygen. Complementarily, lateral force microscopy reveals a homogeneous friction coefficient of the reduced regions that is remarkably lower than that of native graphene oxide, confirming a chemical change in the patterned region. Micro Raman spectroscopy, which provides access to insights into the chemical process, allows one to quantify the restoration and de-oxidation of the graphitic network driven by the electrochemical reduction and to determine characteristic length scales. It also confirms the homogeneity of the process over wide areas. The results shown were obtained from accurate analysis of the shift, intensity and width of Raman peaks for the main vibrational bands of GO and reduced graphene oxide (rGO) mapped over large areas. Concerning multilayered GO thin films obtained by drop-casting we have demonstrated an unprecedented lateral resolution in ambient conditions as well as an improved control, characterization and understanding of the reduction process occurring in GO randomly folded multilayers, useful for large-scale processing of graphene-based material.

Integration of silver nanoparticle-impregnated polyelectrolyte multilayers into murine splinted cutaneous wound beds

PubMed Central

Guthrie, Kathleen M.; Agarwal, Ankit; Teixeira, Leandro B. C.; Dubielzig, Richard R.; Abbott, Nicholas L.; Murphy, Christopher J.; Singh, Harpreet; McAnulty, Jonathan F.; Schurr, Michael J.

2013-01-01

Silver is a commonly used topical antimicrobial. However, technologies to immobilize silver at the wound surface are lacking, while currently available silver-containing wound dressings release excess silver that can be cytotoxic and impair wound healing. We have shown that precise concentrations of silver at lower levels can be immobilized into a wound bed using a polyelectrolyte multilayer (PEM) attachment technology. These silver nanoparticle-impregnated PEMs are non-cytotoxic yet bactericidal in vitro, but their effect on wound healing in vivo was previously unknown. Objective The purpose of this study was to determine the effect on wound healing of integrating silver nanoparticle/PEMs into the wound bed. Methods A full-thickness, splinted, excisional murine wound healing model was employed in both phenotypically normal mice and spontaneously diabetic mice (healing impaired model). Results Gross image measurements showed an initial small lag in healing in the silver-treated wounds in diabetic mice, but no difference in time to complete wound closure in either normal or diabetic mice. Histological analysis showed modest differences between silver-treated and control groups on day 9, but no difference between groups at the time of wound closure. Conclusions We conclude that silver nanoparticle/PEMs can be safely integrated into the wound beds of both normal and diabetic mice without delaying wound closure, and with transient histological effects. The results of this study suggest the feasibility of this technology for use as a platform to effect nanoscale wound engineering approaches to microbial prophylaxis or to augment wound healing. PMID:23511285

Nanoscale structure, dynamics and power conversion efficiency correlations in small molecule and oligomer-based photovoltaic devices

PubMed Central

Szarko, Jodi M.; Guo, Jianchang; Rolczynski, Brian S.; Chen, Lin X.

2011-01-01

Photovoltaic functions in organic materials are intimately connected to interfacial morphologies of molecular packing in films on the nanometer scale and molecular levels. This review will focus on current studies on correlations of nanoscale morphologies in organic photovoltaic (OPV) materials with fundamental processes relevant to photovoltaic functions, such as light harvesting, exciton splitting, exciton diffusion, and charge separation (CS) and diffusion. Small molecule photovoltaic materials will be discussed here. The donor and acceptor materials in small molecule OPV devices can be fabricated in vacuum-deposited, multilayer, crystalline thin films, or spin-coated together to form blended bulk heterojunction (BHJ) films. These two methods result in very different morphologies of the solar cell active layers. There is still a formidable debate regarding which morphology is favored for OPV optimization. The morphology of the conducting films has been systematically altered; using variations of the techniques above, the whole spectrum of film qualities can be fabricated. It is possible to form a highly crystalline material, one which is completely amorphous, or an intermediate morphology. In this review, we will summarize the past key findings that have driven organic solar cell research and the current state-of-the-art of small molecule and conducting oligomer materials. We will also discuss the merits and drawbacks of these devices. Finally, we will highlight some works that directly compare the spectra and morphology of systematically elongated oligothiophene derivatives and compare these oligomers to their polymer counterparts. We hope this review will shed some new light on the morphology differences of these two systems. PMID:22110870

Confinement of surface state electrons in self-organized Co islands on Au(111)

NASA Astrophysics Data System (ADS)

Schouteden, Koen; Lijnen, Erwin; Janssens, Ewald; Ceulemans, Arnout; Chibotaru, Liviu F.; Lievens, Peter; Van Haesendonck, Chris

2008-04-01

We report on detailed low temperature scanning tunneling spectroscopy measurements performed on nanoscale Co islands on Au(111) films. At low coverages, Co islands self-organize in arrays of mono- and bilayer nanoscale structures that often have an hexagonal shape. The process of self-organization is induced by the Au(111) 'herringbone' reconstruction. By means of mapping of the local density of states with lock-in detection, electron standing wave patterns are resolved on top of the atomically flat Co islands. The surface state electrons are observed to be strongly confined laterally inside the Co nanosized islands, with their wavefunctions reflecting the symmetry of the islands. To complement the experimental work, particle-in-a-box calculations were performed. The calculations are based on a newly developed variational method that can be applied to '2D boxes' of arbitrary polygonal shape. The experimental patterns are found to fit nicely to the calculated wavefunctions for a box having a symmetry corresponding to the experimental island symmetry. The small size of the Co islands under study (down to 7.7 nm2) is observed to induce a strong discretization of the energy levels, with very large energy separations between the eigenstates up to several 100 meV. The observed standing wave patterns are identified either as individual eigenstates or as a 'mixture' of two or more energetically close-lying eigenstates of the cobalt island. Additionally, the Co surface state appears not to be limited to mono- and bilayer islands, but this state remains observable for multilayered islands up to five monolayers of Co.

Bioreplicated visual features of nanofabricated buprestid beetle decoys evoke stereotypical male mating flights

PubMed Central

Domingue, Michael J.; Lakhtakia, Akhlesh; Pulsifer, Drew P.; Hall, Loyal P.; Badding, John V.; Bischof, Jesse L.; Martín-Palma, Raúl J.; Imrei, Zoltán; Janik, Gergely; Mastro, Victor C.; Hazen, Missy; Baker, Thomas C.

2014-01-01

Recent advances in nanoscale bioreplication processes present the potential for novel basic and applied research into organismal behavioral processes. Insect behavior potentially could be affected by physical features existing at the nanoscale level. We used nano-bioreplicated visual decoys of female emerald ash borer beetles (Agrilus planipennis) to evoke stereotypical mate-finding behavior, whereby males fly to and alight on the decoys as they would on real females. Using an industrially scalable nanomolding process, we replicated and evaluated the importance of two features of the outer cuticular surface of the beetle’s wings: structural interference coloration of the elytra by multilayering of the epicuticle and fine-scale surface features consisting of spicules and spines that scatter light into intense strands. Two types of decoys that lacked one or both of these elements were fabricated, one type nano-bioreplicated and the other 3D-printed with no bioreplicated surface nanostructural elements. Both types were colored with green paint. The light-scattering properties of the nano-bioreplicated surfaces were verified by shining a white laser on the decoys in a dark room and projecting the scattering pattern onto a white surface. Regardless of the coloration mechanism, the nano-bioreplicated decoys evoked the complete attraction and landing sequence of Agrilus males. In contrast, males made brief flying approaches toward the decoys without nanostructured features, but diverted away before alighting on them. The nano-bioreplicated decoys were also electroconductive, a feature used on traps such that beetles alighting onto them were stunned, killed, and collected. PMID:25225359

Physical vapor deposition as a route to glasses with liquid crystalline order

NASA Astrophysics Data System (ADS)

Gomez, Jaritza

Physical vapor deposition (PVD) is an effective route to prepare glasses with a unique combination of properties. Substrate temperatures near the glass transition (Tg) and slow deposition rates can access enhanced mobility at the surface of the glass allowing molecules at the surface additional time to sample different molecular configurations. The temperature of the substrate can be used to control molecular mobility during deposition and properties in the resulting glasses such as higher density, kinetic stability and preferential molecular orientation. PVD was used to prepare glasses of itraconazole, a smectic A liquid crystal. We characterized molecular orientation using infrared and ellipsometry. Molecular orientation can be controlled by choice of Tsubstrate in a range of temperatures near Tg. Glasses deposited at Tsubstrate = Tg show nearly vertical molecular orientation relative to the substrate; at lower Tsubstrate, molecules are nearly parallel to the substrate. The molecular orientation depends on the temperature of the substrate during preparation and not on the molecular orientation of the underlying layer. This allows preparing samples of layers with differing orientations. We find these glasses are homogeneous solids without evidence of domain boundaries and are molecularly flat. We interpret the combination of properties obtained for vapor-deposited glasses of itraconazole to result from a process where molecular orientation is determined by the structure and dynamics at the free surface of the glass during deposition. We report the thermal and structural properties of glasses prepared using PVD of a rod-like molecule, posaconazole, which does not show equilibrium liquid crystal phases. These glasses show substantial molecular orientation that can be controlled by choice of Tsubstrate during deposition. Ellipsometry and IR indicate that glasses prepared at Tg - 3 K are highly ordered. At these Tsubstrate, molecules show preferential vertical orientation and orientation is similar to that measured in aligned nematic liquid crystal. Our results are consistent with a recently proposed mechanism where molecular orientation in equilibrium liquids can be trapped in PVD glasses and suggest that the orientation at the free surface of posaconazole is nematic-like. In addition, we show posaconazole glasses show high kinetic stability controlled by Tsubstrate.

Treatment of Provoked Vulvodynia in a Swedish cohort using desensitization exercises and cognitive behavioral therapy.

PubMed

Lindström, Suzanne; Kvist, Linda J

2015-11-25

Problems related to pain during vaginal penetration are complex and the etiology is multi-factorial. It was the aim of the present study to measure whether treatment using desensitization exercises and cognitive behavioral therapy (CBT) for women with provoked vulvodynia (PVD) could increase sexual interest, sexual satisfaction and response whilst decreasing experiences of sexual pain. Sixty women suffering from PVD were treated during a 10-week period with a combination of mucosal desensitization and pelvic floor exercises and CBT. The McCoy Female Sexuality Questionnaire (MFSQ) was used to measure efficacy of the treatment. The Hospital Anxiety and Depression Scale (HADS) was used to measure psychological distress. The primary outcome measurements were changes in scores for the MFSQ and changes in individual items on the MFSQ directly after treatment completion. Secondary outcome measurements were changes in the MFSQ items 6 months after treatment and changes in HADS sub-scales 6 months after treatment. Statistical comparisons of answers to the MFSQ were carried out using the Wilcoxon signed rank test (paired). Validity of the MFSQ in this study was measured by testing one global question about sexuality and total scores on MFSQ using Spearman's correlation test. Study participants reported a statistically significant increase in sexual fantasies, increased sexual pleasure, excitement and vaginal lubrication after treatment was completed. PVD occurred less often which resulted in significantly less avoidance of sexual intercourse, increased frequency of masturbation and intercourse. All improvements were sustained at 6 months after treatment ended. Two questions showed no significant changes, these pertained to the individual's contentment with her partner as a lover and a friend. The anxiety sub-scale of the HADS showed a significantly decreased level of anxiety at 6 months follow-up but no change in the scores on the depression sub-scale. Treatment for PVD using desensitization exercises and cognitive behavioral therapy significantly improved sexual interest, response and activity and decreased the experience of pain. Larger studies and RCTs are required in order to draw conclusions about treatment and long term effects should be studied. Partners should be encouraged to participate in treatment regimes. The study is registered with ISRCTN registry, ID ISRCTN40416405.

The Incorporation of Lithium Alloying Metals into Carbon Matrices for Lithium Ion Battery Anodes

NASA Astrophysics Data System (ADS)

Hays, Kevin A.

An increased interest in renewable energies and alternative fuels has led to recognition of the necessity of wide scale adoption of the electric vehicle. Automotive manufacturers have striven to produce an electric vehicle that can match the range of their petroleum-fueled counterparts. However, the state-of-the-art lithium ion batteries used to power the current offerings still do not come close to the necessary energy density. The energy and power densities of the lithium ion batteries must be increased significantly if they are going to make electric vehicles a viable option. The chemistry of the lithium ion battery, based on lithium cobalt oxide cathodes and graphite anodes, is limited by the amount of lithium the cathode can provide and the anode will accept. While these materials have proven themselves in portable electronics over the past two decades, plausible higher energy alternatives do exist. The focus is of this study is on anode materials that could achieve a capacity of more than 3 times greater than that of graphite anodes. The lithium alloying anode materials investigated and reported herein include tin, arsenic, and gallium arsenide. These metals were synthesized with nanoscale dimensions, improving their electrochemical and mechanical properties. Each exhibits their own benefits and challenges, but all display opportunities for incorporation in lithium ion batteries. Tin is incorporated in multilayer graphene nanoshells by introducing small amounts of metal in the core and, separately, on the outside of these spheres. Electrolyte decomposition on the anode limits cycle life of the tin cores, however, tin vii oxides introduced outside of the multilayer graphene nanoshells have greatly improved long term battery performance. Arsenic is a lithium alloying metal that has largely been ignored by the research community to date. One of the first long term battery performance tests of arsenic is reported in this thesis. Anodes were made from nanoscale arsenic particles that were synthesized on melt away carbon nanotubes by akalide reduction. The performance of these anodes proved sensitive to electrolyte composition, which was significantly improved by using fluorinated ethylene carbonate. Additionally, further gains in capacity retention can be made by limiting the loading voltage to 0.75 V vs lithium metal. The arsenic and melt away carbon nanotube composite was found to have excellent cycle life and capacity at high mass loading (80% arsenic) when the nanoparticles were directly synthesized on the melt away carbon nanotubes. Gallium arsenide is well known for its semiconducting properties, but its performance as in Li-ion battery anodes is first reported here. Gallium is a metal with a low melting point that has been touted as a possible self-healing material for lithium ion anodes. Alone, gallium proves to be unstable as a lithium ion battery anode, but when synthesized as gallium arsenide nanoparticles and mixed with melt away carbon nanotubes it can charge and discharge in a battery 100 times with approximately twice the capacity of graphite anodes. This first study of gallium arsenide shows dramatic cycle life improvements by using nanoscale rather that micron size gallium arsenide.

The environmental applications and implications of nanotechnology in membrane-based separations for water treatment

NASA Astrophysics Data System (ADS)

Shan, Wenqian

This dissertation presents results of three related projects focused on the applications of membrane separation technology to water treatment: 1) Experimental design and evaluation of polyelectrolyte multilayer films as regenerable membrane coatings with controllable surface properties; 2) Modeling of the interactions of nanoscale TiO2 and NOM molecules in aqueous solutions of environmentally relevant compositions; 3) Experimental design and preliminary testing of a membrane-based crossflow filtration hydrocyclone process for the separation of oil-in-water dispersions. Chapter 2 describes the design of polyelectrolyte multilayers as nanoscale membrane coatings and their application in nanofiltration of feed waters that contain suspended colloids and dissolved species. Layer-by-layer deposition of anionic and cationic polyelectrolytes was employed to prepare membrane coatings allowing for a fine control over their surface properties. This approach to membrane design also affords a possibility of regenerating coatings after they are fouled by colloids. This project demonstrated, for first time, the possibility of designing nanofiltration membranes with regenerable skin. Chapter 3 describes a study on the mechanisms of natural organic matter (NOM) adsorption onto the surface of titania nanoparticles. Titainia (TiO 2) is often used in the fabrication of ceramic membranes and understanding how NOM interacts with TiO2 can help to better predict ceramic membrane fouling by NOM-containing waters. The combined effect of pH and calcium on the interactions of nonozonated and ozonated NOM with nanoscale TiO 2 was investigated by applying extended Derjaguin --- Landau --- Verwey - Overbeek (XDLVO) modeling. XDLVO surface energy analysis predicted NOM adsorption onto TiO2 in the ozone-controlled regime but not in the calcium-controlled regime. In both regimes, short range NOM-NOM and NOM-TiO2 interactions were governed by acid-base and van der Waals forces, whereas the role of electrostatic forces was found to be relatively insignificant. Ozonation increased the surface energy of NOM, contributing to the hydrophilic repulsion component of the NOM-NOM and NOM-TiO2 interactions. In the calcium-controlled regime, non-XDLVO interactions such as intermolecular bridging by calcium were hypothesized to be responsible for the observed adsorption behavior. Chapter 4 describes research on the crossflow filtration hydrocyclone separation of oil-in-water dispersions wherein a ceramic tubular membrane was used as the permeable wall of the hydrocyclone. Air sparging was applied to mitigate oil fouling. A dual membrane system consisting of an outer hydrophilic ceramic membrane and an inner hydrophobic polymeric membrane was evaluated to test the possibility of separating the dispersion into two streams: 1) oil with zero or very low concentration of water and 2) water with zero or very low concentration of oil. The performance of the dual membrane system indicated the possibility of using membranes with different chemical affinities to cost-effectively separate the oil-water dispersion into two separate phases. The incorporation of air sparging to membrane filtration was found to be effective in mitigating oil fouling with improved permeate flux.

Surface Evolution of Nano-Textured 4H-SiC Homoepitaxial Layers after High Temperature Treatments: Morphology Characterization and Graphene Growth.

PubMed

Liu, Xingfang; Chen, Yu; Sun, Changzheng; Guan, Min; Zhang, Yang; Zhang, Feng; Sun, Guosheng; Zeng, Yiping

2015-09-18

Nano-textured 4H-SiC homoepitaxial layers (NSiCLs) were grown on 4H-SiC(0001) substrates using a low pressure chemical vapor deposition technique (LPCVD), and subsequently were subjected to high temperature treatments (HTTs) for investigation of their surface morphology evolution and graphene growth. It was found that continuously distributed nano-scale patterns formed on NSiCLs which were about submicrons in-plane and about 100 nanometers out-of-plane in size. After HTTs under vacuum, pattern sizes reduced, and the sizes of the remains were inversely proportional to the treatment time. Referring to Raman spectra, the establishment of multi-layer graphene (MLG) on NSiCL surfaces was observed. MLG with sp ² disorders was obtained from NSiCLs after a high temperature treatment under vacuum at 1700 K for two hours, while MLG without sp ² disorders was obtained under Ar atmosphere at 1900 K.

Spin-Transfer Studies in Magnetic Multilayer Nanostructures

NASA Astrophysics Data System (ADS)

Emley, N. C.; Albert, F. J.; Ryan, E. M.; Krivorotov, I. N.; Ralph, D. C.; Buhrman, R. A.

2003-03-01

Numerous experiments have demonstrated current-induced magnetization reversal in ferromagnet/paramagnet/ferromagnet nanostructures with the current in the CPP geometry. The primary mechanism for this reversal is the transfer of angular momentum from the spin-polarized conduction electrons to the nanomagnet moment the spin transfer effect. This phenomenon has potential application in nanoscale, current-controlled non-volatile memory elements, but several challenges must be overcome for realistic device implementation. Typical Co/Cu/Co nanopillar devices, although effective for fundamental studies, are not advantageous for technological applications because of their large switching currents Ic ( 3-10 mA) and small R·A (< 1 mΩ·µm^2). Here we report initial results testing some possible approaches for enhancing spin-transfer device performance which involve the addition of more layers, and hence, more complexity, to the simple Co/Cu/Co trilayer structure. These additions include synthetic antiferromagnet layers (SAF), exchange biased layers, nano-oxide layers (NOL), and additional magnetic layers. Research supported by NSF and DARPA

3D Printed PEG-Based Hybrid Nanocomposites Obtained by Sol-Gel Technique.

PubMed

Chiappone, Annalisa; Fantino, Erika; Roppolo, Ignazio; Lorusso, Massimo; Manfredi, Diego; Fino, Paolo; Pirri, Candido Fabrizio; Calignano, Flaviana

2016-03-02

In this work, three-dimensional (3D) structured hybrid materials were fabricated combining 3D printing technology with in situ generation of inorganic nanoparticles by sol-gel technique. Those materials, consisting of silica nanodomains covalently interconnected with organic polymers, were 3D printed in complex multilayered architectures, incorporating liquid silica precursors into a photocurable oligomer in the presence of suitable photoinitiators and exposing them to a digital light system. A post sol-gel treatment in acidic vapors allowed the in situ generation of the inorganic phase in a dedicated step. This method allows to build hybrid structures operating with a full liquid formulation without meeting the drawbacks of incorporating inorganic powders into 3D printable formulations. The influence of the generated silica nanoparticle on the printed objects was deeply investigated at macro- and nanoscale; the resulting light hybrid structures show improved mechanical properties and, thus, have a huge potential for applications in a variety of advanced technologies.

Fibronectin-based multilayer thin films.

PubMed

Gand, Adeline; Tabuteau, Maud; Chat, Coline; Ladam, Guy; Atmani, Hassan; Van Tassel, Paul R; Pauthe, Emmanuel

2017-08-01

Thin films mimicking the structure and composition of the extra-cellular matrix (ECM) are potentially attractive as biomaterials for cell contacting applications. Layer-by-layer (LbL) assembly of a biological polycation, poly(l-lysine) (PLL), and a common ECM protein, fibronectin (Fn), was employed here to construct nanoscale, ECM mimicking films. Incremental film thickness and interfacial charge magnitude are observed to diminish with layer number, resulting in sub-linear film growth scaling and saturation after about 10 layers. Infrared spectroscopy and electron microscopy together reveal the formation of Fn containing aggregates, whose presence correlates with diminished charge reversal and suppressed LbL assembly. PLL-Fn films induce a significantly greater murine MC3T3-E1 pre-osteoblastic cell proliferation, while maintaining a much higher proportion of Fn in the molecular (as opposed to fibrillar) state, compared to a Fn monolayer, suggesting the enhanced Fn content of these ECM-mimicking films to significantly, and positively, affect cell behavior. Copyright © 2017 Elsevier B.V. All rights reserved.

X-ray fluorescence at nanoscale resolution for multicomponent layered structures: A solar cell case study

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

West, Bradley M.; Stuckelberger, Michael; Jeffries, April

The study of a multilayered and multicomponent system by spatially resolved X-ray fluorescence microscopy poses unique challenges in achieving accurate quantification of elemental distributions. This is particularly true for the quantification of materials with high X-ray attenuation coefficients, depth-dependent composition variations and thickness variations. A widely applicable procedure for use after spectrum fitting and quantification is described. This procedure corrects the elemental distribution from the measured fluorescence signal, taking into account attenuation of the incident beam and generated fluorescence from multiple layers, and accounts for sample thickness variations. Deriving from Beer–Lambert's law, formulae are presented in a general integral formmore » and numerically applicable framework. Here, the procedure is applied using experimental data from a solar cell with a Cu(In,Ga)Se 2 absorber layer, measured at two separate synchrotron beamlines with varied measurement geometries. This example shows the importance of these corrections in real material systems, which can change the interpretation of the measured distributions dramatically.« less

X-ray fluorescence at nanoscale resolution for multicomponent layered structures: A solar cell case study

DOE PAGES

West, Bradley M.; Stuckelberger, Michael; Jeffries, April; ...

2017-01-01

The study of a multilayered and multicomponent system by spatially resolved X-ray fluorescence microscopy poses unique challenges in achieving accurate quantification of elemental distributions. This is particularly true for the quantification of materials with high X-ray attenuation coefficients, depth-dependent composition variations and thickness variations. A widely applicable procedure for use after spectrum fitting and quantification is described. This procedure corrects the elemental distribution from the measured fluorescence signal, taking into account attenuation of the incident beam and generated fluorescence from multiple layers, and accounts for sample thickness variations. Deriving from Beer–Lambert's law, formulae are presented in a general integral formmore » and numerically applicable framework. Here, the procedure is applied using experimental data from a solar cell with a Cu(In,Ga)Se 2 absorber layer, measured at two separate synchrotron beamlines with varied measurement geometries. This example shows the importance of these corrections in real material systems, which can change the interpretation of the measured distributions dramatically.« less

Dimensional Effects on the Charge Density Waves in Ultrathin Films of TiSe 2

DOE PAGES

Chen, P.; Chan, Y. -H.; Wong, M. -H.; ...

2016-09-20

Charge density wave (CDW) formation in solids is a critical phenomenon involving the collective reorganization of the electrons and atoms in the system into a wave structure, and it is expected to be sensitive to the geometric constraint of the system at the nanoscale. Here, we study the CDW transition in TiSe 2, a quasi-two-dimensional layered material, to determine the effects of quantum confinement and changing dimensions in films ranging from a single layer to multilayers. Of key interest is the characteristic length scale for the transformation from a two-dimensional case to the three-dimensional limit. Angle-resolved photoemission (ARPES) measurements ofmore » films with thicknesses up to six layers reveal substantial variations in the energy structure of discrete quantum well states; however, the temperature-dependent band-gap renormalization converges at just three layers. The results indicate a layer-dependent mixture of two transition temperatures and a very-short-range CDW interaction within a three-dimensional framework.« less

Three-Dimensional CdS/Au Butterfly Wing Scales with Hierarchical Rib Structures for Plasmon-Enhanced Photocatalytic Hydrogen Production.

PubMed

Fang, Jing; Gu, Jiajun; Liu, Qinglei; Zhang, Wang; Su, Huilan; Zhang, Di

2018-06-13

Localized surface plasmon resonance (LSPR) of plasmonic metals (e.g., Au) can help semiconductors improve their photocatalytic hydrogen (H 2 ) production performance. However, an artificial synthesis of hierarchical plasmonic structures down to nanoscales is usually difficult. Here, we adopt the butterfly wing scales from Morpho didius to fabricate three-dimensional (3D) CdS/Au butterfly wing scales for plasmonic photocatalysis. The as-prepared materials well-inherit the pristine hierarchical biostructures. The 3D CdS/Au butterfly wing scales exhibit a high H 2 production rate (221.8 μmol·h -1 within 420-780 nm), showing a 241-fold increase over the CdS butterfly wing scales. This is attributed to the effective potentiation effect of LSPR introduced by multilayer metallic rib structures and a good interface bonding state between Au and CdS nanoparticles. Thus, our study provides a relatively simple method to learn from nature and inspiration for preparing highly efficient plasmonic photocatalysts.

Transparent superwetting nanofilms with enhanced durability at model physiological condition

PubMed Central

Hwangbo, Sunghee; Heo, Jiwoong; Lin, Xiangde; Choi, Moonhyun; Hong, Jinkee

2016-01-01

There have been many studies on superwetting surfaces owing to the variety of their potential applications. There are some drawbacks to developing these films for biomedical applications, such as the fragility of the microscopic roughness feature that is vital to ensure superwettability. But, there are still only a few studies that have shown an enhanced durability of nanoscale superwetting films at certain extreme environment. In this study, we fabricated intrinsically stable superwetting films using the organosilicate based layer-by-layer (LbL) self-assembly method in order to control nano-sized roughness of the multilayer structures. In order to develop mechanically and chemically robust surfaces, we successfully introduced polymeric silsesquioxane as a building block for LbL assembly with desired fashion. Even in the case that the superhydrophobic outer layers were damaged, the films maintained their superhydrophobicity because of the hydrophobic nature of their inner layers. As a result, we successfully fabricated superwetting nano-films and evaluated their robustness and stability. PMID:26764164

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

Chen, P.; Pai, Woei Wu; Chan, Y. -H.

Two-dimensional materials constitute a promising platform for developing nanoscale devices and systems. Their physical properties can be very different from those of the corresponding three-dimensional materials because of extreme quantum confinement and dimensional reduction. Here in this paper we report a study of TiTe 2 from the single-layer to the bulk limit. Using angle-resolved photoemission spectroscopy and scanning tunneling microscopy and spectroscopy, we observed the emergence of a (2 × 2) charge density wave order in single-layer TiTe 2 with a transition temperature of 92 ± 3 K. Also observed was a pseudogap of about 28 meV at the Fermimore » level at 4.2 K. Surprisingly, no charge density wave transitions were observed in two-layer and multi-layer TiTe 2 , despite the quasi-two-dimensional nature of the material in the bulk. The unique charge density wave phenomenon in the single layer raises intriguing questions that challenge the prevailing thinking about the mechanisms of charge density wave formation.« less

Polymer multilayers loaded with antifungal β-peptides kill planktonic Candida albicans and reduce formation of fungal biofilms on the surfaces of flexible catheter tubes.

PubMed

Raman, Namrata; Lee, Myung-Ryul; Palecek, Sean P; Lynn, David M

2014-10-10

Candida albicans is the most common fungal pathogen responsible for hospital-acquired infections. Most C. albicans infections are associated with the implantation of medical devices that act as points of entry for the pathogen and as substrates for the growth of fungal biofilms that are notoriously difficult to eliminate by systemic administration of conventional antifungal agents. In this study, we report a fill-and-purge approach to the layer-by-layer fabrication of biocompatible, nanoscale 'polyelectrolyte multilayers' (PEMs) on the luminal surfaces of flexible catheters, and an investigation of this platform for the localized, intraluminal release of a cationic β-peptide-based antifungal agent. We demonstrate that polyethylene catheter tubes with luminal surfaces coated with multilayers ~700nm thick fabricated from poly-l-glutamic acid (PGA) and poly-l-lysine (PLL) can be loaded, post-fabrication, by infusion with β-peptide, and that this approach promotes extended intraluminal release of this agent (over ~4months) when incubated in physiological media. The β-peptide remained potent against intraluminal inoculation of the catheters with C. albicans and substantially reduced the formation of C. albicans biofilms on the inner surfaces of film-coated catheters. Finally, we report that these β-peptide-loaded coatings exhibit antifungal activity under conditions that simulate intermittent catheter use and microbial challenge for at least three weeks. We conclude that β-peptide-loaded PEMs offer a novel and promising approach to kill C. albicans and prevent fungal biofilm formation on surfaces, with the potential to substantially reduce the incidence of device-associated infections in indwelling catheters. β-Peptides comprise a promising new class of antifungal agents that could help address problems associated with the use of conventional antifungal agents. The versatility of the layer-by-layer approach used here thus suggests additional opportunities to exploit these new agents in other biomedical and personal care applications in which fungal infections are endemic. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantitative SIMS depth profiling of diffusion barrier gate-oxynitride structures in TFT-LCDs.

PubMed

Dreer, Sabine; Wilhartitz, Peter; Piplits, Kurt; Mayerhofer, Karl; Foisner, Johann; Hutter, Herbert

2004-06-01

Gate oxynitride structures of TFT-LCDs were investigated by SIMS, and successful solutions are demonstrated to overcome difficulties arising due to the charging effects of the multilayer systems, the matrix effect of the method, and the small pattern sizes of the samples. Because of the excellent reproducibility achieved by applying exponential relative sensitivity functions for quantitative analysis, minor differences in the barrier gate-oxynitride composition deposited on molybdenum capped aluminium-neodymium metallisation electrodes were determined between the centre and the edge of the TFT-LCD substrates. No differences were found for molybdenum-tungsten metallisations. Furthermore, at the edge of the glass substrates, aluminium, neodymium, and molybdenum SIMS depth profiles show an exponential trend. With TEM micrographs an inhomogeneous thickness of the molybdenum capping is revealed as the source of this effect, which influences the electrical behaviour of the device. The production process was improved after these results and the aging behaviour of TFT-LCDs was investigated in order to explain the change in control voltage occurring during the lifetime of the displays. SIMS and TEM show an enrichment of neodymium at the interface to the molybdenum layer, confirming good diffusion protection of the molybdenum barrier during accelerated aging. The reason for the shift of the control voltage was finally located by semi-quantitative depth profiling of the sodium diffusion originating from the glass substrate. Molybdenum-tungsten was a much better buffer for the highly-mobile charge carriers than aluminium-neodymium. Best results were achieved with PVD silicon oxynitride as diffusion barrier and gate insulator deposited on aluminium-neodymium metallisation layers.

A Constructed Wetland: From Monitoring To Action.

ERIC Educational Resources Information Center

Kowal, Dan

1998-01-01

Presents a water-quality monitoring project in a Denver school that has evolved into an experiment using a constructed wetland system to treat the acid-mine drainage from an abandoned gold mine. (PVD)

Regularly arranged indium islands on glass/molybdenum substrates upon femtosecond laser and physical vapor deposition processing

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

Ringleb, F.; Eylers, K.; Teubner, Th.

2016-03-14

A bottom-up approach is presented for the production of arrays of indium islands on a molybdenum layer on glass, which can serve as micro-sized precursors for indium compounds such as copper-indium-gallium-diselenide used in photovoltaics. Femtosecond laser ablation of glass and a subsequent deposition of a molybdenum film or direct laser processing of the molybdenum film both allow the preferential nucleation and growth of indium islands at the predefined locations in a following indium-based physical vapor deposition (PVD) process. A proper choice of laser and deposition parameters ensures the controlled growth of indium islands exclusively at the laser ablated spots. Basedmore » on a statistical analysis, these results are compared to the non-structured molybdenum surface, leading to randomly grown indium islands after PVD.« less

Crack prediction in EB-PVD thermal barrier coatings based on the simulation of residual stresses

NASA Astrophysics Data System (ADS)

Chen, J. W.; Zhao, Y.; Liu, S.; Zhang, Z. Z.; Ma, J.

2016-07-01

Thermal barrier coatings systems (TBCs) are widely used in the field of aerospace. The durability and insulating ability of TBCs are highly dependent on the residual stresses of top coatings, thus the investigation of the residual stresses is helpful to understand the failure mechanisms of TBCs. The simulation of residual stresses evolution in electron beam physical vapor deposition (EB-PVD) TBCs is described in this work. The interface morphology of TBCs subjected to cyclic heating and cooling is observed using scanning electron microscope (SEM). An interface model of TBCs is established based on thermal elastic-plastic finite method. Residual stress distributions in TBCs are obtained to reflect the influence of interfacial roughness. Both experimental and simulation results show that it is feasible to predict the crack location by stress analysis, which is crucial to failure prediction.

Mercuric iodide medical imagers for low-exposure radiography and fluoroscopy

NASA Astrophysics Data System (ADS)

Zentai, George; Partain, Larry; Pavlyuchkova, Raisa; Proano, Cesar; Breen, Barry N.; Taieb, A.; Dagan, Ofer; Schieber, Michael; Gilboa, Haim; Thomas, Jerry

2004-05-01

Photoconductive polycrystalline mercuric iodide deposited on flat panel thin film transistor (TFT) arrays is being developed for direct digital X-ray detectors that can perform both radiographic and fluoroscopic medical imaging. The mercuric iodide is either vacuum deposited by Physical Vapor Deposition (PVD) or coated onto the array by a wet Particle-In-Binder (PIB) process. The PVD deposition technology has been scaled up to the 20 cm x 25 cm size required in common medical imaging applications. A TFT array with a pixel pitch of 127 microns is used for these imagers. Arrays of 10 cm x 10 cm size have been used to evaluate performance of mercuric iodide imagers. Radiographic and fluoroscopic images of diagnostic quality at up to 15 pulses per second were demonstrated. As we previously reported, the resolution is limited to the TFT array Nyquist frequency of ~3.9 lp/mm (127 micron pixel pitch). Detective Quantum Efficiency (DQE) has been measured as a function of spatial frequency for these imagers. The DQE is lower than the theoretically calculated value due to some additional noise sources of the electronics and the array. We will retest the DQE after eliminating these noise sources. Reliability and stress testing was also began for polycrystalline mercuric iodide PVD and PIB detectors. These are simplified detectors based upon a stripe electrode or circular electrode structure. The detectors were stressed under various voltage bias, temperature and time conditions. The effects of the stress tests on the detector dark current and sensitivity were determined.

Comorbid anxiety disorders alter the association between cardiovascular diseases and depression: the German National Health Interview and Examination Survey.

PubMed

Tully, Phillip J; Baune, Bernhard T

2014-05-01

This study aims to examine whether specific anxiety disorder comorbidity alters the purported association between depression and specific cardiovascular diseases (CVDs). In 4,181 representative German participants of the general population, 12-month prevalence of psychiatric disorders was assessed through the Composite International Diagnostic Interview and CVDs by physician verified diagnosis. Adjusting for conventional risk factors logistic regression analyzed the association between CVDs (peripheral vascular disease (PVD), hypertension, cerebrovascular disease and heart disease) and combinations of comorbidity between depression and anxiety disorder types (panic disorder, specific phobia, social phobia and generalized anxiety). There were 770 cases of hypertension (18.4 %), 763 cases of cerebrovascular disease (18.2 %), 748 cases of PVD (17.9 %), and 1,087 cases of CVD (26.0 %). In adjusted analyses phobia comorbid with depression was associated with cerebrovascular disease (odds ratio (OR) 1.61; 95 % confidence interval (CI) 1.04-2.50) as was panic disorder (OR 2.89; 95 % CI 1.47-5.69). PVD was significantly associated with panic disorder (adjusted OR 2.97; 95 % CI 1.55-5.69). Panic disorder was associated with CVDs (adjusted OR 2.28; 95 % CI 1.09-4.77) as was phobia (adjusted OR 1.35; 95 % CI 1.04-1.78). Classification of anxiety and depression according to comorbidity groups showed discrete effects for panic disorder and specific phobia with CVDs, independent from covariates and depression.

Postvibration depression of the H-reflex as a result of a dual mechanism: an experimental study in humans.

PubMed

Abbruzzese, M; Minatel, C; Reni, L; Favale, E

2001-09-01

Changes in amplitude of the soleus H (S(H))-reflex and its neurographic correlates (P(1) and P(2) waves) after vibration of the soleus muscle have been evaluated as a function of mechanical stimulation frequency, duration of the conditioning train, and test stimulus intensity. Additional experiments aimed at assessing the nervous system mechanisms underlying the postvibration depression (PVD) have been performed. In particular, homonymous (S(HMR) or S(H)) versus heteronymous (S(HTR)) soleus response, evoked respectively by tibial nerve and femoral nerve electrical stimulation, the effectiveness of sub-H threshold tibial nerve conditioning volleys on the S(HTR), and the respective effects of a brief passive stretching of the quadriceps and soleus muscles on the recovery of both the S(HMR) and S(HTR) after vibration of the homologous muscle were investigated under suitable experimental conditions. It was found that PVD occurs in the absence of changes in amplitude of the P(1) wave and the S(HTR), is paralleled by a reduced effectiveness of tibial nerve-conditioning volleys on the S(HTR) and is shortened consistently by brief passive stretching of the homologous muscle. It follows that PVD may be the result of a long-lasting reduction of the transmitter release from Ia presynaptic terminals depending, at least in part, on a protracted postvibration Ia afferent discharge caused by spindles thixotropy. These findings may provide a better understanding of the pathophysiologic mechanisms underlying spasticity in humans.

Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator.

PubMed

Park, Sejoon; Son, Chung Woo; Lee, Sungho; Kim, Dong Young; Park, Cheolmin; Eom, Kwang Sup; Fuller, Thomas F; Joh, Han-Ik; Jo, Seong Mu

2016-11-11

Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO 2 ) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB.

Multicore-shell nanofiber architecture of polyimide/polyvinylidene fluoride blend for thermal and long-term stability of lithium ion battery separator

PubMed Central

Park, Sejoon; Son, Chung Woo; Lee, Sungho; Kim, Dong Young; Park, Cheolmin; Eom, Kwang Sup; Fuller, Thomas F.; Joh, Han-Ik; Jo, Seong Mu

2016-01-01

Li-ion battery, separator, multicoreshell structure, thermal stability, long-term stability. A nanofibrous membrane with multiple cores of polyimide (PI) in the shell of polyvinylidene fluoride (PVdF) was prepared using a facile one-pot electrospinning technique with a single nozzle. Unique multicore-shell (MCS) structure of the electrospun composite fibers was obtained, which resulted from electrospinning a phase-separated polymer composite solution. Multiple PI core fibrils with high molecular orientation were well-embedded across the cross-section and contributed remarkable thermal stabilities to the MCS membrane. Thus, no outbreaks were found in its dimension and ionic resistance up to 200 and 250 °C, respectively. Moreover, the MCS membrane (at ~200 °C), as a lithium ion battery (LIB) separator, showed superior thermal and electrochemical stabilities compared with a widely used commercial separator (~120 °C). The average capacity decay rate of LIB for 500 cycles was calculated to be approximately 0.030 mAh/g/cycle. This value demonstrated exceptional long-term stability compared with commercial LIBs and with two other types (single core-shell and co-electrospun separators incorporating with functionalized TiO2) of PI/PVdF composite separators. The proper architecture and synergy effects of multiple PI nanofibrils as a thermally stable polymer in the PVdF shell as electrolyte compatible polymers are responsible for the superior thermal performance and long-term stability of the LIB. PMID:27833132

Birthdays and the Binary System: A Magical Mixture.

ERIC Educational Resources Information Center

Karp, Karen S.; Ronau, Robert N.

1997-01-01

Presents an activity involving the use of students' birth dates. Activity includes a classic binary representation of numerical values. In the Green Machine, Sorting Cards, and Window Cards, students observe, describe, and analyze patterns. (PVD)

Lemon Cells Revisited--The Lemon-Powered Calculator.

ERIC Educational Resources Information Center

Swartling, Daniel J.; Morgan, Charlotte

1998-01-01

Describes a demonstration of the principles of a voltaic cell using lemon cells to power a calculator and other items. A lemon fortified with a penny and a galvanized nail produces a potential of one volt. (PVD)

A Mechanical Analogue for Chemical Potential, Extent of Reaction, and the Gibbs Energy.

ERIC Educational Resources Information Center

Glass, Samuel V.; DeKock, Roger L.

1998-01-01

Presents an analogy that relates the one-dimensional mechanical equilibrium of a rigid block between two Hooke's law springs and the chemical equilibrium of two perfect gases using ordinary materials. (PVD)

Investigation of failure mechanism of thermal barrier coatings (TBCs) deposited by EB-PVD technique

NASA Astrophysics Data System (ADS)

Shahid, M. R.; Abbas, Musharaf

2013-06-01

Failure mechanism of thermal barrier coatings (TBCs) prepared by electron beam physical vapor deposition (EB-PVD) technique owing to formation of micro cracks was investigated. The TBCs were deposited on the Ni-based super alloy IN-100 and the micro cracks were observed within the top ceramic coat of thermally cycled TBCs at 1050°C. It was observed that these cracks propagate in the ceramic coat in the direction normal to interface while no cracks were observed in the bond coat. SEM/EDS studies revealed that some non-uniform oxides were formed on the interface between ceramic top and metallic bond coat just below the cracks. Study proposed that the cracks were initiated due to stress owing to big difference in Pilling-Bed worth ratio of non-uniform oxides as well as thermal stress, which caused the formation of cracks in top ceramic coat leading to failure of TBCs

Composite polymer electrolyte based on PEO/Pvdf-HFP with MWCNT for lithium battery applications

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

Pradeepa, P.; Edwinraj, S.; Sowmya, G.

In the present study PEO and PVdF-HFP blend based composite polymer electrolytes (CPEs) has been prepared by using Multi Walled Carbon Nanotube (MWCNT), in order to examine the filler addition effect on the electrochemical properties. The complexed nanocomposite polymer electrolytes were obtained in the form of dimensionally stable and free standing films by using solution casting technique. The electrochemical properties of CPEs were measured by the AC impedance method. From the ionic conductivity results, the CPE containing MWCNT 2wt% showed the highest ionic conductivity with an excellent thermal stability at room temperature. The dielectric loss curve s for the samplemore » 6.25wt% PEO: 18.75 wt% PVdF-HFP: 2wt% MWCNT reveal the low frequency β relaxation peak pronounced at high temperature, and it may caused by side group dipoles.« less

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

Some Non-FDA Approved Uses for Neuromodulation: A Review of the Evidence.

PubMed

Lee, Samuel; Abd-Elsayed, Alaa

2016-09-01

Neuromodulation, including spinal cord stimulation and peripheral nerve field stimulation, has been used with success in treating several painful conditions. The FDA approved the use of neuromodulation for a few indications. We review evidence for neuromodulation in treating some important painful conditions that are not currently FDA approved. This review included an online web search for only clinical trials testing the efficacy of neuromodulation in treating coronary artery disease, peripheral vascular disease (PVD), headache, and peripheral field stimulation. Our systematic literature search found 10, 6, and 3 controlled studies relating to coronary artery disease, PVD, and headache, respectively. Our review also included 5 noncontrolled studies relating to peripheral field stimulation, as no controlled studies had been completed. This review article shows compelling evidence based on clinical trials that neuromodulation can be of benefit for patients with serious painful conditions that are not currently approved by the FDA. © 2015 World Institute of Pain.

Nonflammable gel electrolyte containing alkyl phosphate for rechargeable lithium batteries

NASA Astrophysics Data System (ADS)

Yoshimoto, Nobuko; Niida, Yoshihiro; Egashira, Minato; Morita, Masayuki

A nonflammable polymeric gel electrolyte has been developed for rechargeable lithium battery systems. The gel film consists of poly(vinylidenefluoride- co-hexafluoropropylene) (PVdF-HFP) swollen with lithium hexafluorophosphate (LiPF 6) solution in ternary solvent containing trimethyl phosphate (TMP). High ionic conductivity of 6.2 mS cm -1 at 20 °C was obtained for the gel electrolyte consisting of 0.8 M LiPF 6/EC + DEC + TMP (55:25:20) with PVdF-HFP, which is comparable to that of the liquid electrolyte containing the same electrolytic salt. Addition of a small amount of vinylene carbonate (VC) in the gel electrolyte improved the rechargeability of a graphite electrode. The rechargeable capacity of the graphite in the gel containing VC was ca. 300 mAh g -1, which is almost the same as that in a conventional liquid electrolyte system.

Low Contrast Dose Catheter-Directed CT Angiography (CCTA)

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

Formosa, Amanda, E-mail: amandaformosa@yahoo.ca; Santos, Denise May, E-mail: contact@denisemaysantos.com; Marcuzzi, Daniel

2016-04-15

PurposeCatheter-directed computed tomography angiography (CCTA) has been shown to reduce the contrast volumes required in conventional CTA, thus minimizing the risk of contrast-induced nephropathy (CIN).Materials and MethodsA retrospective analysis was performed on cases where CCTA was used to assess access vessels prior to transfemoral aortic valve implantation (TAVI, n = 53), abdominal aortic aneurysm assessment for endovascular aneurysm repair (EVAR, n = 11), and peripheral vascular disease (PVD, n = 24).ResultsWe show that CCTA can image vasculature with adequate diagnostic detail to allow assessment of lower extremity disease, anatomic suitability for EVAR, as well as potential contraindications to TAVI. Average contrast volumes for pre-TAVI, pre-EVAR, andmore » PVD cases were 7, 11, and 28 mL, respectively.ConclusionThis study validates the use of CCTA in obtaining diagnostic images of the abdominal and pelvic vessels and in imaging lower extremity vasculature.« less

New deposition technique for metal films containing inorganic fullerene-like (IF) nanoparticles.

PubMed

Goldbart, Ohad; Yoffe, Alexander; Cohen, Sidney R; Rosentsveig, Rita; Feldman, Yishay; Rapoport, Lev; Tenne, Reshef

2013-07-22

This study describes a new method for fabrication of thin composite films using physical vapor deposition (PVD). Titanium (Ti) and hybrid films of titanium containing tungsten disulphide nanoparticles with inorganic fullerene-like structure (Ti/IF-WS2) were fabricated with a modified PVD machine. The evaporation process includes the pulsed deposition of IF-WS2 by a sprayer head. This process results in IF-WS2 nanoparticles embedded in a Ti matrix. The layers were characterized by various techniques, which confirm the composition and structure of the hybrid film. The Ti/IF-WS2 shows better wear resistance and a lower friction coefficient when compared to the Ti layer or Ti substrate. The Ti/IF films show very good antireflective properties in the visible and near-IR region. Such films may find numerous applications, for example, in the aerospace and medical technology. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of Surface Finishing on the Oxidation Behaviour of VPS MCrAlY Coatings

NASA Astrophysics Data System (ADS)

Fossati, Alessio; di Ferdinando, Martina; Bardi, Ugo; Scrivani, Andrea; Giolli, Carlo

2012-03-01

CoNiCrAlY coatings were produced by means of the vacuum plasma spraying (VPS) process onto CMSX-4 single crystal nickel superalloy disk substrates. As-sprayed samples were annealed at high temperatures in low vacuum. Three kinds of finishing processes were carried out, producing three types of samples: as-sprayed, mechanically smoothed by grinding, ground and PVD coated by using aluminum targets in an oxygen atmosphere. Samples were tested under isothermal conditions, in air, at 1000 °C, and up to 5000 h. Morphological, microstructural and compositional analyses were performed on the coated samples in order to assess the high temperature oxidation behavior provided by the three different surface finishing processes. Several differences were observed: grinding operations decrease the oxidation resistance, whereas the PVD process can increase the performances over longer time with respect of the as-sprayed samples.

Micro- and Macrocirculatory Changes During Sepsis and Septic Shock in a Rat Model.

PubMed

Hua, Tianfeng; Wu, Xiaobo; Wang, Wei; Li, Hao; Bradley, Jennifer; Peberdy, Mary A; Ornato, Joseph P; Tang, Wanchun

2018-05-01

Microcirculation is the motor of sepsis. In the present study, we investigated whether microcirculatory alterations occur before changes of systemic hemodynamics in a rat model of cecum ligation and puncture (CLP)-induced sepsis. We further investigated renal microcirculatory changes during sepsis and compared those with buccal microcirculation. Twelve male Sprague-Dawley rats were randomized into a sham control group (n = 6) and a CLP group (n = 6). Perfused microvessel density (PVD) and microvascular flow index (MFI) were evaluated using sidestream dark field (SDF) video microscopy at baseline-60, 120, 180, 240, 300, and 360 min following CLP. A semiquantitative score was calculated for vessels of less than 20 μm, primarily representing the capillaries. Hemodynamic measurements such as cardiac output (CO), aortic pressure (AP), heart rate (HR), end-tidal CO2 (ETCO2), blood pH, and lactate were measured simultaneously. The serum cytokine interleukin 6 (IL-6) was measured at baseline-120, 240, and 360 min. In the CLP group, buccal PVD and MFI were reduced at 180 min (P < 0.05 vs. baseline); renal PVD and MFI were reduced at 180 min (P < 0.05 vs. baseline), but MAP and CO did not change until 300 min after CLP. In the rat model of peritonitis-induced sepsis, microcirculatory alterations of both peripheral mucosa and kidney occurred earlier than global hemodynamics. Monitoring the microcirculation may provide a means of early detection of circulatory failure during sepsis. The changes of renal microcirculation correlate with that of buccal during sepsis and septic shock.

Electrodynamic pressure modulation of protein stability in cosolvents.

PubMed

Damodaran, Srinivasan

2013-11-19

Cosolvents affect structural stability of proteins in aqueous solutions. A clear understanding of the mechanism by which cosolvents impact protein stability is critical to understanding protein folding in a biological milieu. In this study, we investigated the Lifshitz-van der Waals dispersion interaction of seven different solutes with nine globular proteins and report that in an aqueous medium the structure-stabilizing solutes exert a positive electrodynamic pressure, whereas the structure-destabilizing solutes exert a negative electrodynamic pressure on the proteins. The net increase in the thermal denaturation temperature (ΔTd) of a protein in 1 M solution of various solutes was linearly related to the electrodynamic pressure (PvdW) between the solutes and the protein. The slope of the PvdW versus ΔTd plots was protein-dependent. However, we find a positive linear relationship (r(2) = 0.79) between the slope (i.e., d(ΔTd)/dPvdW) and the adiabatic compressibility (βs) of the proteins. Together, these results clearly indicate that the Lifshitz's dispersion forces are inextricably involved in solute-induced stabilization/destabilization of globular proteins. The positive and/or negative electrodynamic pressure generated by the solute-protein interaction across the water medium seems to be the fundamental mechanism by which solutes affect protein stability. This is at variance with the existing preferential hydration concept. The implication of these results is significant in the sense that, in addition to the hydrophobic effect that drives protein folding, the electrodynamic forces between the proteins and solutes in the biological milieu also might play a role in the folding process as well as in the stability of the folded state.

Black hole mass measurement using molecular gas kinematics: what ALMA can do

NASA Astrophysics Data System (ADS)

Yoon, Ilsang

2017-04-01

We study the limits of the spatial and velocity resolution of radio interferometry to infer the mass of supermassive black holes (SMBHs) in galactic centres using the kinematics of circum-nuclear molecular gas, by considering the shapes of the galaxy surface brightness profile, signal-to-noise ratios (S/Ns) of the position-velocity diagram (PVD) and systematic errors due to the spatial and velocity structure of the molecular gas. We argue that for fixed galaxy stellar mass and SMBH mass, the spatial and velocity scales that need to be resolved increase and decrease, respectively, with decreasing Sérsic index of the galaxy surface brightness profile. We validate our arguments using simulated PVDs for varying beam size and velocity channel width. Furthermore, we consider the systematic effects on the inference of the SMBH mass by simulating PVDs including the spatial and velocity structure of the molecular gas, which demonstrates that their impacts are not significant for a PVD with good S/N unless the spatial and velocity scale associated with the systematic effects are comparable to or larger than the angular resolution and velocity channel width of the PVD from pure circular motion. Also, we caution that a bias in a galaxy surface brightness profile owing to the poor resolution of a galaxy photometric image can largely bias the SMBH mass by an order of magnitude. This study shows the promise and the limits of ALMA observations for measuring SMBH mass using molecular gas kinematics and provides a useful technical justification for an ALMA proposal with the science goal of measuring SMBH mass.

Surgical management in patients with coexistent coronary and cerebrovascular disease. Long-term results.

PubMed

Kaul, T K; Fields, B L; Wyatt, D A; Jones, C R; Kahn, D R

1994-11-01

Between January 1980 and December 1992, 3% (210/6,862) of our patients undergoing myocardial revascularization (CABG) had high grade (> 80%) internal carotid stenosis (CS). One hundred seventy-five of these patients with complete follow up for a minimum of 18 months were studied. Bilateral internal CS was present in 60%, and 75% had other vascular lesions, mainly as peripheral vascular disease (PVD) of the lower limb (50.8%). All patients underwent CAE (carotid endarterectomy) followed by CABG under the same anesthesia. Peripheral vascular lesions, contralateral internal CS and recurrent (n = 43) and progressive vascular lesions (n = 50), were subsequently treated as staged procedures. Hospital mortality was 3.42%. By univariate analysis significant predictors of late mortality were congestive heart failure, COPD, PVD, postoperative myocardial infarction, postoperative stroke, and ischemic cardiomyopathy. Only the latter two were also significant by multivariate analysis. At 12 years, actuarial survival in the presence of these risk factors were 46%, 49%, 22%, 37%, 53%, and 27% respectively. All are significantly lower as compared with the corresponding subsets of patients with the risk factor absent. At 12 years, actuarial survival for the entire series was 65%. Cumulative incidence of postoperative strokes was higher in patients with bilateral internal CS than in patients with unilateral internal CS (p < 0.07) and in patients with neurologic symptoms than asymptomatic patients. At 12 years, actuarial freedom from all cardiac related events, postoperative stroke, and symptomatic PVD were 49%, 82%, and 76% respectively. After successful revascularization these patients should be carefully followed for recurrent and progressive vascular lesions.

Nanotechnology finding its way into flame retardancy

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

Schartel, Bernhard, E-mail: bernhard.schartel@bam.de

2014-05-15

Nanotechnology is one of the key technologies of the 21{sup st} century. The exploitation of 'new' effects that arise from materials structured on the nano-scale has also been proposed successfully for flame retardancy of polymers since the end of the 90s. Of all of the approaches these include, at this time the use of nanocomposites offers the best potential for industrial application, also some other ideas are sketched, such as using electrospun nanofibers mats or layer-by-layer deposits as protection coatings, as well as sub-micrometer multilayer coatings as effective IR-mirrors. The general phenomena, inducing a flow limit in the pyrolysing meltmore » and changing the fire residue, are identified in nanocomposites. Key experiments are performed such as quasi online investigation of the protection layer formation to understand what is going on in detail. The flame retardancy mechanisms are discussed and their impact on fire behaviour quantified. With the latter, the presentation pushes forward the state of the art. For instance, the heat shielding is experimentally quantified for a layered silicate epoxy resin nanocomposite proving that it is the only import mechanism controlling the reduction in peak heat release rate in the investigated system for different irradiations. The flame retardancy performance is assessed comprehensively illuminating not only the strengths but also the weak points of the concepts. Guidelines for materials development are deduced and discussed. Apart from inorganic fillers (layered silicate, boehmite, etc.) not only carbon nanoobjects such as multiwall carbon nanotubes, multilayer graphene and graphene are investigated, but also nanoparticles that are more reactive and harbor the potential for more beneficial interactions with the polymer matrix.« less

Self-organization during growth of ZrN/SiN{sub x} multilayers by epitaxial lateral overgrowth

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

Fallqvist, A.; Fager, H.; Hultman, L.

ZrN/SiN{sub x} nanoscale multilayers were deposited on ZrN seed layers grown on top of MgO(001) substrates by dc magnetron sputtering with a constant ZrN thickness of 40 Å and with an intended SiN{sub x} thickness of 2, 4, 6, 8, and 15 Å at a substrate temperature of 800 °C and 6 Å at 500 °C. The films were investigated by X-ray diffraction, high-resolution scanning transmission electron microscopy, and energy dispersive X-ray spectroscopy. The investigations show that the SiN{sub x} is amorphous and that the ZrN layers are crystalline. Growth of epitaxial cubic SiN{sub x}—known to take place on TiN(001)—onmore » ZrN(001) is excluded to the monolayer resolution of this study. During the course of SiN{sub x} deposition, the material segregates to form surface precipitates in discontinuous layers for SiN{sub x} thicknesses ≤6 Å that coalesce into continuous layers for 8 and 15 Å thickness at 800 °C, and for 6 Å at 500 °C. The SiN{sub x} precipitates are aligned vertically. The ZrN layers in turn grow by epitaxial lateral overgrowth on the discontinuous SiN{sub x} in samples deposited at 800 °C with up to 6 Å thick SiN{sub x} layers. Effectively a self-organized nanostructure can be grown consisting of strings of 1–3 nm large SiN{sub x} precipitates along apparent column boundaries in the epitaxial ZrN.« less

Evaluation of wick drain performance in Virginia soils.

DOT National Transportation Integrated Search

2003-01-01

Prefabricated vertical drains (PVD), also known as wick drains, are commonly used to accelerate the consolidation of fine-grained soils in order to reduce future settlements and increase shear strength. Various drain designs are currently on the mark...

Eat Your Weedies!

ERIC Educational Resources Information Center

Duke, James

2001-01-01

Explains the value of harvesting garden weeds and eating them. Discusses antioxidant and other nutritional qualities of weeds, weeds that are especially useful as raw or cooked vegetables, the importance of weed identification, and the dangers of weed-killing herbicides. Highlights purslane. (PVD)

Determining Iron Content in Foods by Spectrophotometry.

ERIC Educational Resources Information Center

Adams, Paul E.

1995-01-01

Describes a laboratory experiment for secondary school chemistry students utilizing the classic reaction between the iron(III) ion and the thiocyanate ion. The experiment also works very well in other chemistry courses as an experience in spectrophotometric analysis. (PVD)

Technology and Environmental Education: Friend or Foe?

ERIC Educational Resources Information Center

Athman, Julie; Bates, Tim

1998-01-01

Discusses the pros and cons often mentioned concerning technology in education. Describes measures of effectiveness of technology-enhanced educational programs, ranging from active learning and multidisciplinary tasks to performance-based assessments. Argues that technology should enhance rather than replace direct experiences. (PVD)

Modeling Antibody Diversity.

ERIC Educational Resources Information Center

Baker, William P.; Moore, Cathy Ronstadt

1998-01-01

Understanding antibody structure and function is difficult for many students. The rearrangement of constant and variable regions during antibody differentiation can be effectively simulated using a paper model. Describes a hands-on laboratory exercise which allows students to model antibody diversity using readily available resources. (PVD)

Applying Chromatography.

ERIC Educational Resources Information Center

Klein, Jessie W.; Patev, Paul

1998-01-01

Presents three experiments to introduce students to different kinds of chromatography: (1) paper chromatography; (2) gel filtration chromatography; and (3) reverse-phase liquid chromatography. Written in the form of a laboratory manual, explanations of each of the techniques, materials needed, procedures, and a glossary are included. (PVD)

Multimodal hard x-ray imaging with resolution approaching 10 nm for studies in material science

NASA Astrophysics Data System (ADS)

Yan, Hanfei; Bouet, Nathalie; Zhou, Juan; Huang, Xiaojing; Nazaretski, Evgeny; Xu, Weihe; Cocco, Alex P.; Chiu, Wilson K. S.; Brinkman, Kyle S.; Chu, Yong S.

2018-03-01

We report multimodal scanning hard x-ray imaging with spatial resolution approaching 10 nm and its application to contemporary studies in the field of material science. The high spatial resolution is achieved by focusing hard x-rays with two crossed multilayer Laue lenses and raster-scanning a sample with respect to the nanofocusing optics. Various techniques are used to characterize and verify the achieved focus size and imaging resolution. The multimodal imaging is realized by utilizing simultaneously absorption-, phase-, and fluorescence-contrast mechanisms. The combination of high spatial resolution and multimodal imaging enables a comprehensive study of a sample on a very fine length scale. In this work, the unique multimodal imaging capability was used to investigate a mixed ionic-electronic conducting ceramic-based membrane material employed in solid oxide fuel cells and membrane separations (compound of Ce0.8Gd0.2O2‑x and CoFe2O4) which revealed the existence of an emergent material phase and quantified the chemical complexity at the nanoscale.

A method to restrain the charging effect on an insulating substrate in high energy electron beam lithography

NASA Astrophysics Data System (ADS)

Mingyan, Yu; Shirui, Zhao; Yupeng, Jing; Yunbo, Shi; Baoqin, Chen

2014-12-01

Pattern distortions caused by the charging effect should be reduced while using the electron beam lithography process on an insulating substrate. We have developed a novel process by using the SX AR-PC 5000/90.1 solution as a spin-coated conductive layer, to help to fabricate nanoscale patterns of poly-methyl-methacrylate polymer resist on glass for phased array device application. This method can restrain the influence of the charging effect on the insulating substrate effectively. Experimental results show that the novel process can solve the problems of the distortion of resist patterns and electron beam main field stitching error, thus ensuring the accuracy of the stitching and overlay of the electron beam lithography system. The main characteristic of the novel process is that it is compatible to the multi-layer semiconductor process inside a clean room, and is a green process, quite simple, fast, and low cost. It can also provide a broad scope in the device development on insulating the substrate, such as high density biochips, flexible electronics and liquid crystal display screens.

Strong field localization in subwavelength metal-dielectric optical waveguides

NASA Astrophysics Data System (ADS)

Kozina, O. N.; Mel'Nikov, L. A.; Nefedov, I. S.

2011-08-01

Detailed calculations of eigenmodes of waveguiding structures made of silver and glass and containing coaxial cables with a nanoscale cross section of different configurations are conducted. In particular, the study focuses on optical coaxial waveguides with the core made in the form of a thin metallic cylinder filled with a dielectric. We show that these waveguides support relatively low-loss propagation of radiation that is strongly localized in the central region, has phase velocity approaching the speed of light and predominant electric-field orientation (dipole type). Optical characteristics of such waveguides are compared with those of coaxial-type waveguides containing a continuous central filament made of metal and with a multilayer structure. Using numeric modeling, we established that the proposed type of the waveguide enables the transmission of an optical image with relatively low losses with a submicron resolution over a distance considerably longer than its cross section. A typical propagation length in the waveguides based on silver and glass with the refractive index of about 1.5 at a wavelength of 500 nm is about 1700 nm.

Self-transducing silicon nanowire electromechanical systems at room temperature.

PubMed

He, Rongrui; Feng, X L; Roukes, M L; Yang, Peidong

2008-06-01

Electronic readout of the motions of genuinely nanoscale mechanical devices at room temperature imposes an important challenge for the integration and application of nanoelectromechanical systems (NEMS). Here, we report the first experiments on piezoresistively transduced very high frequency Si nanowire (SiNW) resonators with on-chip electronic actuation at room temperature. We have demonstrated that, for very thin (~90 nm down to ~30 nm) SiNWs, their time-varying strain can be exploited for self-transducing the devices' resonant motions at frequencies as high as approximately 100 MHz. The strain of wire elongation, which is only second-order in doubly clamped structures, enables efficient displacement transducer because of the enhanced piezoresistance effect in these SiNWs. This intrinsically integrated transducer is uniquely suited for a class of very thin wires and beams where metallization and multilayer complex patterning on devices become impractical. The 30 nm thin SiNW NEMS offer exceptional mass sensitivities in the subzeptogram range. This demonstration makes it promising to advance toward NEMS sensors based on ultrathin and even molecular-scale SiNWs, and their monolithic integration with microelectronics on the same chip.

Atomic-scale friction modulated by potential corrugation in multi-layered graphene materials

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

Zhuang, Chunqiang, E-mail: chunqiang.zhuang@bjut.edu.cn; Liu, Lei

2015-03-21

Friction is an important issue that has to be carefully treated for the fabrication of graphene-based nano-scale devices. So far, the friction mechanism of graphene materials on the atomic scale has not yet been clearly presented. Here, first-principles calculations were employed to unveil the friction behaviors and their atomic-scale mechanism. We found that potential corrugations on sliding surfaces dominate the friction force and the friction anisotropy of graphene materials. Higher friction forces correspond to larger corrugations of potential energy, which are tuned by the number of graphene layers. The friction anisotropy is determined by the regular distributions of potential energy.more » The sliding along a fold-line path (hollow-atop-hollow) has a relatively small potential energy barrier. Thus, the linear sliding observed in macroscopic friction experiments may probably be attributed to the fold-line sliding mode on the atomic scale. These findings can also be extended to other layer-structure materials, such as molybdenum disulfide (MoS{sub 2}) and graphene-like BN sheets.« less

Synthesis of millimeter-scale transition metal dichalcogenides single crystals

DOE PAGES

Gong, Yongji; Ye, Gonglan; Lei, Sidong; ...

2016-02-10

The emergence of semiconducting transition metal dichalcogenide (TMD) atomic layers has opened up unprecedented opportunities in atomically thin electronics. Yet the scalable growth of TMD layers with large grain sizes and uniformity has remained very challenging. Here is reported a simple, scalable chemical vapor deposition approach for the growth of MoSe2 layers is reported, in which the nucleation density can be reduced from 105 to 25 nuclei cm -2, leading to millimeter-scale MoSe 2 single crystals as well as continuous macrocrystalline films with millimeter size grains. The selective growth of monolayers and multilayered MoSe2 films with well-defined stacking orientation canmore » also be controlled via tuning the growth temperature. In addition, periodic defects, such as nanoscale triangular holes, can be engineered into these layers by controlling the growth conditions. The low density of grain boundaries in the films results in high average mobilities, around ≈42 cm 2 V -1 s -1, for back-gated MoSe 2 transistors. This generic synthesis approach is also demonstrated for other TMD layers such as millimeter-scale WSe 2 single crystals.« less

Emergence of charge density waves and a pseudogap in single-layer TiTe 2

DOE PAGES

Chen, P.; Pai, Woei Wu; Chan, Y. -H.; ...

2017-09-11

Two-dimensional materials constitute a promising platform for developing nanoscale devices and systems. Their physical properties can be very different from those of the corresponding three-dimensional materials because of extreme quantum confinement and dimensional reduction. Here in this paper we report a study of TiTe 2 from the single-layer to the bulk limit. Using angle-resolved photoemission spectroscopy and scanning tunneling microscopy and spectroscopy, we observed the emergence of a (2 × 2) charge density wave order in single-layer TiTe 2 with a transition temperature of 92 ± 3 K. Also observed was a pseudogap of about 28 meV at the Fermimore » level at 4.2 K. Surprisingly, no charge density wave transitions were observed in two-layer and multi-layer TiTe 2 , despite the quasi-two-dimensional nature of the material in the bulk. The unique charge density wave phenomenon in the single layer raises intriguing questions that challenge the prevailing thinking about the mechanisms of charge density wave formation.« less

Highly conductive ribbons prepared by stick-slip assembly of organosoluble gold nanoparticles.

PubMed

Lawrence, Jimmy; Pham, Jonathan T; Lee, Dong Yun; Liu, Yujie; Crosby, Alfred J; Emrick, Todd

2014-02-25

Precisely positioning and assembling nanoparticles (NPs) into hierarchical nanostructures is opening opportunities in a wide variety of applications. Many techniques employed to produce hierarchical micrometer and nanoscale structures are limited by complex fabrication of templates and difficulties with scalability. Here we describe the fabrication and characterization of conductive nanoparticle ribbons prepared from surfactant-free organosoluble gold nanoparticles (Au NPs). We used a flow-coating technique in a controlled, stick-slip assembly to regulate the deposition of Au NPs into densely packed, multilayered structures. This affords centimeter-scale long, high-resolution Au NP ribbons with precise periodic spacing in a rapid manner, up to 2 orders-of-magnitude finer and faster than previously reported methods. These Au NP ribbons exhibit linear ohmic response, with conductivity that varies by changing the binding headgroup of the ligands. Controlling NP percolation during sintering (e.g., by adding polymer to retard rapid NP coalescence) enables the formation of highly conductive ribbons, similar to thermally sintered conductive adhesives. Hierarchical, conductive Au NP ribbons represent a promising platform to enable opportunities in sensing, optoelectronics, and electromechanical devices.

Linking Electricity for Peace: A Compelling Global Strategy.

ERIC Educational Resources Information Center

Meisen, Peter

1997-01-01

Comparative trend analysis shows striking improvements in all major societal indicators as electricity becomes available to developing nations. Discusses the linking of electrical grids between countries and across continents and the ramifications for standards of living, sustainable development, and world peace. (PVD)

Demonstrating Phase Changes.

ERIC Educational Resources Information Center

Rohr, Walter

1995-01-01

Presents two experiments that demonstrate phase changes. The first experiment explores phase changes of carbon dioxide using powdered dry ice sealed in a piece of clear plastic tubing. The second experiment demonstrates an equilibrium process in which a crystal grows in equilibrium with its saturated solution. (PVD)

Photovoltaic device and method

DOEpatents

Cleereman, Robert J; Lesniak, Michael J; Keenihan, James R; Langmaid, Joe A; Gaston, Ryan; Eurich, Gerald K; Boven, Michelle L

2015-01-27

The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.

Photovoltaic device and method

DOEpatents

Cleereman, Robert; Lesniak, Michael J.; Keenihan, James R.; Langmaid, Joe A.; Gaston, Ryan; Eurich, Gerald K.; Boven, Michelle L.

2015-11-24

The present invention is premised upon an improved photovoltaic device ("PVD") and method of use, more particularly to an improved photovoltaic device with an integral locator and electrical terminal mechanism for transferring current to or from the improved photovoltaic device and the use as a system.

Economic burden of cardiovascular events and fractures among patients with end-stage renal disease.

PubMed

Doan, Quan V; Gleeson, Michelle; Kim, John; Borker, Rohit; Griffiths, Robert; Dubois, Robert W

2007-07-01

To quantify direct medical costs of fractures and cardiovascular diseases among end-stage renal disease (ESRD) patients. Medicare claims data from year 2001 of the United States Renal Data System were used to quantify direct medical costs of acute episodic events (acute myocardial infarction (MI), stroke, heart valve repair, heart valve replacement, fractures) and chronic conditions (arrhythmia, peripheral vascular disease (PVD), heart valve disease (HVD), congestive heart failure (CHF), coronary heart disease, and non-acute stroke). Costs of hospitalized episodes of arrhythmia, PVD, CHF, and angina were also quantified. For acute events, costs were quantified using an episode-of-care approach. For chronic conditions, annualized costs were reported. Only costs specific to the events or conditions of interest were included and reported, in 2006 US dollars. Drug and dialysis-related costs were excluded. Diagnosis and procedure codes were used to identify these events and conditions. Among acute events analyzed as clinical episodes, PVD ($358 million) was associated with the greatest economic burden, followed by CHF, arrhythmia, angina, acute MI, heart valve replacement, hip fracture, acute stroke, heart valve repair, vertebral fracture, and pelvic fracture ($8.6 million). The cost per episode ranged from approximately $12,000 to 104,000. Among chronic conditions, CHF ($681 million) contributed the greatest economic burden; HVD ($100 million) contributed the least. The costs per patient-year ranged from $23,000 to 45,000 among chronic conditions. The costing methodology utilized could contribute to an underestimate of the economic impact of each condition; therefore these results are considered conservative. The economic burden of these selected conditions was substantial to health services payers who finance ESRD patient care. Episodic costs were high for most acute events.

Injection moulding of optical functional micro structures using laser structured, PVD-coated mould inserts

NASA Astrophysics Data System (ADS)

Hopmann, Ch.; Weber, M.; Schöngart, M.; Schäfer, C.; Bobzin, K.; Bagcivan, N.; Brögelmann, T.; Theiß, S.; Münstermann, T.; Steger, M.

2015-05-01

Micro structured optical plastics components are intensively used i. e. in consumer electronics, for optical sensors in metrology, innovative LED-lighting or laser technology. Injection moulding has proven to be successful for the large-scale production of those parts. However, the production of those parts still causes difficulties due to challenges in the moulding and demoulding of plastics parts created with laser structured mould inserts. A complete moulding of the structures often leads to increased demoulding forces, which then cause a breaking of the structures and a clogging of the mould. An innovative approach is to combine PVD-coated (physical vapour deposition), laser structured inserts and a variothermal moulding process to create functional mic8iüro structures in a one-step process. Therefore, a PVD-coating is applied after the laser structuring process in order to improve the wear resistance and the anti-adhesive properties against the plastics melt. In a series of moulding trials with polycarbonate (PC) and polymethylmethacrylate (PMMA) using different coated moulds, the mould temperature during injection was varied in the range of the glass transition and the melt temperature of the polymers. Subsequently, the surface topography of the moulded parts is evaluated by digital 3D laser-scanning microscopy. The influence of the moulding parameters and the coating of the mould insert on the moulding accuracy and the demoulding behaviour are being analysed. It is shown that micro structures created by ultra-short pulse laser ablation can be successfully replicated in a variothermal moulding process. Due to the mould coating, significant improvements could be achieved in producing micro structured optical plastics components.

Clinical Features of Psychogenic Voice Disorder and the Efficiency of Voice Therapy and Psychological Evaluation.

PubMed

Tezcaner, Zahide Çiler; Gökmen, Muhammed Fatih; Yıldırım, Sibel; Dursun, Gürsel

2017-11-06

The aim of this study was to define the clinical features of psychogenic voice disorder (PVD) and explore the treatment efficiency of voice therapy and psychological evaluation. Fifty-eight patients who received treatment following the PVD diagnosis and had no organic or other functional voice disorders were assessed retrospectively based on laryngoscopic examinations and subjective and objective assessments. Epidemiological characteristics, accompanying organic and psychological disorders, preferred methods of treatment, and previous treatment outcomes were examined for each patient. A comparison was made based on voice disorders and responses to treatment between patients who received psychotherapy and patients who did not. Participants in this study comprised 58 patients, 10 male and 48 female. Voice therapy was applied in all patients, 54 (93.1%) of whom had improvement in their voice. Although all patients were advised to undergo psychological assessment, only 60.3% (35/58) of them underwent psychological assessment. No statistically significant difference was found between patients who did receive psychological support concerning their treatment responses and patients who did not. Relapse occurred in 14.7% (5/34) of the patients who applied for psychological assessment and in 50% (10/20) of those who did not. There was a statistically significant difference in relapse rates, which was higher among patients who did not receive psychological support (P < 0.005). Voice therapy is an efficient treatment method for PVD. However, in the long-term follow-up, relapse of the disease is observed to be higher among patients who failed to follow up on the recommendation for psychological assessment. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

Magnitude of dyslipedemia and its association with micro and macro vascular complications in type 2 diabetes: a hospital based study from Bikaner (Northwest India).

PubMed

Agrawal, R P; Sharma, Poornima; Pal, Mahender; Kochar, A; Kochar, D K

2006-08-01

Type 2 diabetes is not only associated with hyperglycemia but also with disorders of lipid metabolism. The aim of this study was to investigate the association of dyslipedemia with micro and macro vascular complications of diabetes. Population based cross sectional study included 4067 diabetic patients who visited hospital during January 2000 to December 2002. Lipid profile was estimated by semi autoanalyser, Retinopathy was assessed by fundoscopy, Nephropathy by microalbuminurea, coronary artery disease (CAD) by electro cardiogram (ECG) changes, peripheral vascular disease (PVD) by doppler study and neuropathy by clinical examinations. The association of dyslipedemia with micro and macro vascular complications was assessed by regression analysis. The prevalence of dyslipedemia is high in diabetic population with high serum cholesterol >240mg/dl was seen in 15%, serum triglycerides >160mg/dl was seen in 42.41%, raised LDL >130mg/dl in 45.26%, VLDL >40mg/dl in 24.09% and low levels of HDL-C <40mg/dl were seen in 52.27%. On regression analysis, CAD had strong correlation with high levels of VLDL (0.76), triglycerides (0.82), LDL (0.23) and low HDL (-0.81). Similar association was seen with PVD. Diabetic retinopathy and nephropathy were found to have significant correlation with low HDL (-0.43) and raised LDL (0.37), respectively. Neuropathy was not found to have any significant correlation with lipid profile abnormalities. Lipid profile abnormalities are very common in type 2 diabetes and it has great influence on CAD and PVD. Hence, appropriate preventive and treatment strategies should be considered timely.

Changes in co-morbidity pattern in patients starting renal replacement therapy in Europe-data from the ERA-EDTA Registry.

PubMed

Ceretta, Maria L; Noordzij, Marlies; Luxardo, Rosario; De Meester, Johan; Abad Diez, Jose M; Finne, Patrik; Heaf, James G; Couchoud, Cécile; Kramar, Reinhard; Collart, Frederic; Cases, Aleix; Palsson, Runolfur; Reisæter, Anna V; Rydell, Helena; Massy, Ziad A; Jager, Kitty J; Kramer, Anneke

2018-01-18

Patients starting renal replacement therapy (RRT) for end-stage renal disease often present with one or more co-morbidities. This study explored the prevalence of co-morbidities in patients who started RRT in Europe during the period from 2005 to 2014. Using data from patients aged 20 years or older from all 11 national or regional registries providing co-morbidity data to the European Renal Association - European Dialysis and Transplant Association Registry, we examined the prevalence of the following co-morbidities: diabetes mellitus (DM) (primary renal disease and/or co-morbidity), ischaemic heart disease (IHD), congestive heart failure (CHF), peripheral vascular disease (PVD), cerebrovascular disease (CVD) and malignancy. Overall, 70% of 7578 patients who initiated RRT in 2014 presented with at least one co-morbidity: 39.0% presented with DM, 25.0% with IHD, 22.3% with CHF, 17.7% with PVD, 16.4% with malignancy and 15.5% with CVD. These percentages differed substantially between countries. Co-morbidities were more common in men than in women, in older patients than in younger patients, and in patients on haemodialysis at Day 91 when compared with patients on peritoneal dialysis. Between 2005 and 2014 the prevalence of DM and malignancy increased over time, whereas the prevalence of IHD and PVD declined. More than two-thirds of patients initiating RRT in Europe have at least one co-morbidity. With the rising age at the start of RRT over the last decade, there have been changes in the co-morbidity pattern: the prevalence of cardiovascular co-morbidities decreased, while the prevalence of DM and malignancy increased. © The Author(s) 2018. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Evaluation of p53 Polymorphism in Patients with Pannus-Derived Prosthetic Dysfunction.

PubMed

Gursoy, Mustafa Ozan; Karakoyun, Suleyman; Kalcik, Macit; Yesin, Mahmut; Gunduz, Sabahattin; Astarcioğlu, Mehmet Ali; Oğuz, Ali Emrah; Ozkan, Mehmet

2015-09-01

Prosthetic valve dysfunction (PVD) due to pannus formation is considered to occur due to a bioreaction to prosthetic material. The p53 gene plays a critical role in apoptosis and cell proliferation. p53 Arg72Pro polymorphism has been found to be associated with coronary stent restenosis, but has not yet been studied in prosthetic heart valve dysfunction. The study aim was to evaluate the association between pannus-derived PVD and p53 G72C(Arg72Pro) polymorphism. This single-center, prospective study included 25 patients (20 females, five males; mean age 45.6 +/- 12.5 years; group 1) who underwent redo valve surgery due to PVD, and 49 age- and gender-matched control patients (44 females, five males; mean age 47.3 +/- 12.2 years; group 2) with normofunctional prostheses. The prostheses were examined using transthoracic and transesophageal echocardiography. Analyses of p53 G72C(Arg72Pro) polymorphism were performed using Roche LightCyler 2.0 Real-time polymerase chain reaction. The most common location of replaced valves was the mitral position in both groups (88% and 89.8%, respectively). In group 1, normal alleles (GG) were observed in 12 patients (48%), while one patient (4%) showed a homozygous mutation (GC) and 12 patients (48%) showed a heterozygous mutation (CC). In group 2, 21 patients (42.9%) had normal alleles (GG), while four (8.2%) had a homozygous mutation (CC) and 24 (48.9%) had a heterozygous mutation (GC). No significant difference was observed between the groups with regards to p53 Arg72Pro polymorphism (p = 0.769). In patients with prosthetic valves, the underlying mechanism behind pannus formation is unrelated to p53 Arg72Pro polymorphism.

Tribological and Wear Performance of Nanocomposite PVD Hard Coatings Deposited on Aluminum Die Casting Tool.

PubMed

Paiva, Jose Mario; Fox-Rabinovich, German; Locks Junior, Edinei; Stolf, Pietro; Seid Ahmed, Yassmin; Matos Martins, Marcelo; Bork, Carlos; Veldhuis, Stephen

2018-02-28

In the aluminum die casting process, erosion, corrosion, soldering, and die sticking have a significant influence on tool life and product quality. A number of coatings such as TiN, CrN, and (Cr,Al)N deposited by physical vapor deposition (PVD) have been employed to act as protective coatings due to their high hardness and chemical stability. In this study, the wear performance of two nanocomposite AlTiN and AlCrN coatings with different structures were evaluated. These coatings were deposited on aluminum die casting mold tool substrates (AISI H13 hot work steel) by PVD using pulsed cathodic arc evaporation, equipped with three lateral arc-rotating cathodes (LARC) and one central rotating cathode (CERC). The research was performed in two stages: in the first stage, the outlined coatings were characterized regarding their chemical composition, morphology, and structure using glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM), and X-ray diffraction (XRD), respectively. Surface morphology and mechanical properties were evaluated by atomic force microscopy (AFM) and nanoindentation. The coating adhesion was studied using Mersedes test and scratch testing. During the second stage, industrial tests were carried out for coated die casting molds. In parallel, tribological tests were also performed in order to determine if a correlation between laboratory and industrial tests can be drawn. All of the results were compared with a benchmark monolayer AlCrN coating. The data obtained show that the best performance was achieved for the AlCrN/Si₃N₄ nanocomposite coating that displays an optimum combination of hardness, adhesion, soldering behavior, oxidation resistance, and stress state. These characteristics are essential for improving the die mold service life. Therefore, this coating emerges as a novelty to be used to protect aluminum die casting molds.

Diffusion bonding of CMSX-4 to UDIMET 720 using PVD-coated interfaces and HIP

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

Larker, R.; Ockborn, J.; Selling, B.

There is an increasing interest in development of manufacturing methods for Dual Property BLISKs (BLaded dISKs), consisting of creep resistant airfoils and fatigue resistant disks bonded together by a durable joint. Optimum heat treatments are, however, very different for creep resistant single crystal CMSX-4 and fatigue resistant polycrystalline Udimet 720 selected in this study, but fortunately the first aging treatment for CMSX-4 (1140 C, 2-6h, AC) is similar to the partial solution treatment of U 720 HS2 (1115 C, 4h, OQ). Based on this, diffusion bonding was performed by HIP at 1120 C and 200 MPa argon pressure for 4more » h, followed by cooling to 400 C. Subsequently, a shortened Udimet 720 HS2 two-step aging treatment was adopted by heating to 650 C for 6 h followed by cooling to 400 C, heating to 760 C for 2 h, and finally cooling to R.T. under remaining HIP pressure. Plasma etching followed by thin (80 nm) PVD coating with either nickel or titanium were used to clean and protect the polished surfaces before joining. The selection of coatings was governed by the possibility to reduce oxidized nickel by flushing with hydrogen at 330 C during evacuation of the HIP capsules, and by the large solubility of oxygen in titanium. Hot tensile testing was performed at 750 C on both joined and reference materials subjected to the modified heat treatment. Initially solution treated Udimet 720 and CMSX-4 comprised the reference materials. The testing showed that joints with Ni-PV coatings were almost as strong as Udimet 720 (although with very limited elongation), while the joints with Ti-PVD coatings were weaker.« less

Low-energy electron-induced reactions in condensed matter

NASA Astrophysics Data System (ADS)

Arumainayagam, Christopher R.; Lee, Hsiao-Lu; Nelson, Rachel B.; Haines, David R.; Gunawardane, Richard P.

2010-01-01

The goal of this review is to discuss post-irradiation analysis of low-energy (≤50 eV) electron-induced processes in nanoscale thin films. Because electron-induced surface reactions in monolayer adsorbates have been extensively reviewed, we will instead focus on low-energy electron-induced reactions in multilayer adsorbates. The latter studies, involving nanoscale thin films, serve to elucidate the pivotal role that the low-energy electron-induced reactions play in high-energy radiation-induced chemical reactions in condensed matter. Although electron-stimulated desorption (ESD) experiments conducted during irradiation have yielded vital information relevant to primary or initial electron-induced processes, we wish to demonstrate in this review that analyzing the products following low-energy electron irradiation can provide new insights into radiation chemistry. This review presents studies of electron-induced reactions in nanoscale films of molecular species such as oxygen, nitrogen trifluoride, water, alkanes, alcohols, aldehydes, ketones, carboxylic acids, nitriles, halocarbons, alkane and phenyl thiols, thiophenes, ferrocene, amino acids, nucleotides, and DNA using post-irradiation techniques such as temperature-programmed desorption (TPD), reflection-absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HREELS), gel electrophoresis, and microarray fluorescence. Post-irradiation temperature-programmed desorption, in particular, has been shown to be useful in identifying labile radiolysis products as demonstrated by the first identification of methoxymethanol as a reaction product of methanol radiolysis. Results of post-irradiation studies have been used not only to identify radiolysis products, but also to determine the dynamics of electron-induced reactions. For example, studies of the radiolysis yield as a function of incident electron energy have shown that dissociative electron attachment plays an important role in the electron-induced single strand breaks in DNA leading to mutagenic damage. Studies such as these not only provide insight into the fundamentals of electron-molecule interactions in the condensed phase but also may provide information valuable to (a) furthering cost-efficient destruction of hazardous chemicals, (b) understanding the electron-induced decomposition of feed gases used in the plasma processing of semiconductor devices, (c) clarifying the role, if any, of low-energy electrons, produced by cosmic rays, contributing to the formation of the ozone hole by interacting with halocarbons and producing Cl atoms, (d) illuminating the dynamics of electron-induced oligomerization and/or polymerization, and (e) explicating the astrochemistry of icy grains.

Digging Deeper with Trees.

ERIC Educational Resources Information Center

Growing Ideas, 2001

2001-01-01

Describes hands-on science areas that focus on trees. A project on leaf pigmentation involves putting crushed leaves in a test tube with solvent acetone to dissolve pigment. In another project, students learn taxonomy by sorting and classifying leaves based on observable characteristics. Includes a language arts connection. (PVD)

The Seat of Insect Learning.

ERIC Educational Resources Information Center

Dyer, Fred C.

1997-01-01

Describes the role of mushroom bodies--cup-shaped structures perched atop the brain of an insect--in learning. Mushroom bodies may help fruit flies in learning meaningful odors, cockroaches in spatial learning, and honeybees both in locating pollen and nectar and in navigating back to the colony. (PVD)

Global Climate Change Interaction Web.

ERIC Educational Resources Information Center

Fortner, Rosanne W.

1998-01-01

Students investigate the effects of global climate change on life in the Great Lakes region in this activity. Teams working together construct as many links as possible for such factors as rainfall, lake water, evaporation, skiing, zebra mussels, wetlands, shipping, walleye, toxic chemicals, coastal homes, and population. (PVD)

Development of biosensors for non-invasive measurements of heart failure biomarkers in saliva

NASA Astrophysics Data System (ADS)

Alcacer, Albert; Streklas, Angelos; Baraket, Abdoullatif; Zine, Nadia; Errachid, Abdelhamid; Bausells, Joan

2017-06-01

Biomedical engineering research today is focused on non-invasive techniques for detection of biomarkers related to specific health issues 1. Three metal layer microelectrode (μE) sensors have been implemented to detect specific biomarkers which can be found in human saliva related with heart failure problems 2 such as interleukin and Tumore Necrosis Factor-α (TNF-α), and used as highly sensitive saliva sensors. We designed specialized μEs combining different technologies for multiple measurements aiming to a lab-on-a-chip future integration. Measurements are based to basic principles of Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). Thus, certain planar technology was used involving three metal layers of gold, platinum and silver deposited over an oxidized silicon substrate following standard cleanroom procedures of lithography for the definition of μEs, sputtering physical vapor deposition (PVD) for gold, evaporation PVD for silver and platinum, and plasma enhanced chemical vapor deposition (PECVD) for passivation layer of silicon nitride.

Derivation of WECC Distributed PV System Model Parameters from Quasi-Static Time-Series Distribution System Simulations

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

Mather, Barry A; Boemer, Jens C.; Vittal, Eknath

The response of low voltage networks with high penetration of PV systems to transmission network faults will, in the future, determine the overall power system performance during certain hours of the year. The WECC distributed PV system model (PVD1) is designed to represent small-scale distribution-connected systems. Although default values are provided by WECC for the model parameters, tuning of those parameters seems to become important in order to accurately estimate the partial loss of distributed PV systems for bulk system studies. The objective of this paper is to describe a new methodology to determine the WECC distributed PV system (PVD1)more » model parameters and to derive parameter sets obtained for six distribution circuits of a Californian investor-owned utility with large amounts of distributed PV systems. The results indicate that the parameters for the partial loss of distributed PV systems may differ significantly from the default values provided by WECC.« less

Ultras-stable Physical Vapor Deposited Amorphous Teflon Films with Extreme Fictive Temperature Reduction

NASA Astrophysics Data System (ADS)

McKenna, Gregory; Yoon, Heedong; Koh, Yung; Simon, Sindee

In the present work, we have produced highly stable amorphous fluoropolymer (Teflon AF® 1600) films to study the calorimetric and relaxation behavior in the deep in the glassy regime. Physical vapor deposition (PVD) was used to produce 110 to 700 nm PVD films with substrate temperature ranging from 0.70 Tg to 0.90 Tg. Fictive temperature (Tf) was measured using Flash DSC with 600 K/s heating and cooling rates. Consistent with prior observations for small molecular weight glasses, large enthalpy overshoots were observed in the stable amorphous Teflon films. The Tf reduction for the stable Teflon films deposited in the vicinity of 0.85 Tg was approximately 70 K compared to the Tgof the rejuvenated system. The relaxation behavior of stable Teflon films was measured using the TTU bubble inflation technique and following Struik's protocol in the temperature range from Tf to Tg. The results show that the relaxation time decreases with increasing aging time implying that devitrification is occurring in this regime.

Controllable fabrication of copper phthalocyanine nanostructure crystals.

PubMed

Liu, Fangmei; Sun, Jia; Xiao, Si; Huang, Wenglong; Tao, Shaohua; Zhang, Yi; Gao, Yongli; Yang, Junliang

2015-06-05

Copper phthalocyanine (CuPc) nanostructure crystals, including nanoflower, nanoribbon, and nanowire, were controllably fabricated by temperature gradient physical vapor deposition (TG-PVD) through controlling the growth parameters. In a controllable growth system with carrier gas N2, nanoflower, nanoribbon, and nanowire crystals were formed in a high-temperature zone, medium-temperature zone, and low-temperature zone, respectively. They were proved to be β-phase, coexist of α-phase and β-phase, and α-phase respectively based on x-ray diffraction results. Furthermore, ultralong CuPc nanowires up to several millimeters could be fabricated by TG-PVD without carrier gas, and they were well-aligned to form large-area CuPc nanowire crystal arrays by the Langmuir-Blodgett method. The nanostructure crystals showed unusual optical absorption spectra from the ultraviolet-visible to near-infrared range, which was explained by the diffraction and scattering caused by the wavelength-sized nanostructures. These CuPc nanostructure crystals show potential applications in organic electronic and optoelectronic devices.

Preparation of Cobalt-Based Electrodes by Physical Vapor Deposition on Various Nonconductive Substrates for Electrocatalytic Water Oxidation.

PubMed

Wu, Yizhen; Wang, Le; Chen, Mingxing; Jin, Zhaoxia; Zhang, Wei; Cao, Rui

2017-12-08

Artificial photosynthesis requires efficient anodic electrode materials for water oxidation. Cobalt metal thin films are prepared through facile physical vapor deposition (PVD) on various nonconductive substrates, including regular and quartz glass, mica sheet, polyimide, and polyethylene terephthalate (PET). Subsequent surface electrochemical modification by cyclic voltammetry (CV) renders these films active for electrocatalytic water oxidation, reaching a current density of 10 mA cm -2 at a low overpotential of 330 mV in 1.0 m KOH solution. These electrodes are robust with unchanged activity throughout prolonged chronopotentiometry measurements. This work is thus significant to show that the combination of PVD and CV is very valuable and convenient to fabricate active electrodes on various nonconductive substrates, particularly with flexible polyimide and PET substrates. This efficient, safe and convenient method can potentially be expanded to many other electrochemical applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

FpvA receptor involvement in pyoverdine biosynthesis in Pseudomonas aeruginosa.

PubMed

Shen, Jiangsheng; Meldrum, Allison; Poole, Keith

2002-06-01

Alignment of the Pseudomonas aeruginosa ferric pyoverdine receptor, FpvA, with similar ferric-siderophore receptors revealed that the mature protein carries an extension of ca. 70 amino acids at its N terminus, an extension shared by the ferric pseudobactin receptors of P. putida. Deletion of fpvA from the chromosome of P. aeruginosa reduced pyoverdine production in this organism, as a result of a decline in expression of genes (e.g., pvdD) associated with the biosynthesis of the pyoverdine peptide moiety. Wild-type fpvA restored pvd expression in the mutant, thereby complementing its pyoverdine deficiency, although a deletion derivative of fpvA encoding a receptor lacking the N terminus of the mature protein did not. The truncated receptor was, however, functional in pyoverdine-mediated iron uptake, as evidenced by its ability to promote pyoverdine-dependent growth in an iron-restricted medium. These data are consistent with the idea that the N-terminal extension plays a role in FpvA-mediated pyoverdine biosynthesis in P. aeruginosa.

Electrospun nanocomposite fibrous polymer electrolyte for secondary lithium battery applications

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

Padmaraj, O.; Rao, B. Nageswara; Jena, Paramananda

2014-04-24

Hybrid nanocomposite [poly(vinylidene fluoride -co- hexafluoropropylene) (PVdF-co-HFP)/magnesium aluminate (MgAl{sub 2}O{sub 4})] fibrous polymer membranes were prepared by electrospinning method. The prepared pure and nanocomposite fibrous polymer electrolyte membranes were soaked into the liquid electrolyte 1M LiPF{sub 6} in EC: DEC (1:1,v/v). XRD and SEM are used to study the structural and morphological studies of nanocomposite electrospun fibrous polymer membranes. The nanocomposite fibrous polymer electrolyte membrane with 5 wt.% of MgAl{sub 2}O{sub 4} exhibits high ionic conductivity of 2.80 × 10{sup −3} S/cm at room temperature. The charge-discharge capacity of Li/LiCoO{sub 2} coin cells composed of the newly prepared nanocomposite [(16more » wt.%) PVdF-co-HFP+(5 wt.%) MgAl{sub 2}O{sub 4}] fibrous polymer electrolyte membrane was also studied and compared with commercial Celgard separator.« less

Pre and post-amputation mobility of trans-tibial amputees: correlation to medical problems, age and mortality.

PubMed

Johnson, V J; Kondziela, S; Gottschalk, F

1995-12-01

This retrospective study compares pre and post-amputation mobility and the influence of age and associated medical problems. Data from the charts of 120 male patients who underwent unilateral trans-tibial (below-knee) amputation at the Dallas Veteran's Administration Hospital between June, 1983 and October, 1991, were collected and analyzed. Mobility was assessed with a six level scale developed by Volpicelli et al. (1983). The presence of cardiac disease, pulmonary disease (COPD), peripheral vascular disease (PVD), diabetes mellitus, degenerative joint disease, blindness, cerebral vascular accident (CVA), and age are correlated with changes in mobility after amputation. Older patients had more medical problems and lower post-amputation scores Individual medical problems did not influence mobility scores, but the presence of COPD and PVD lowered pre-amputation mobility scores. Cardiac disease and diabetes mellitus influenced post-amputation mobility scores by lowering them, either together or individually. Regardless of age, however, patients with more medical problems were poor ambulators. The cause of amputation per se did not influence mobility scores.

The Anatomy of Memory.

ERIC Educational Resources Information Center

Cave, Sitara; Schwartzenberg, Susan

1998-01-01

Fleeting electrochemical connections made between brain cells help people remember the thoughts, skills, experiences, and knowledge that make them unique. Presents the dissection of the brain of a sheep, an animal in which brain structure and function are similar to that in humans, to demonstrate where these processes take place. (PVD)

Using Technology To Enhance Problem Solving and Critical Thinking Skills.

ERIC Educational Resources Information Center

Mingus, Tabitha; Grassl, Richard

1997-01-01

Secondary mathematics teachers participated in a problem-solving course in which technology became a means to develop as teachers and as problem solvers. Findings indicate a delineation between technical competence and metatechnology--thinking about how and when to apply technology to particular problems. (PVD)

Subclinical ketosis in post-partum dairy cows fed a predominantly pasture-based diet: defining cut-points for diagnosis using concentrations of beta-hydroxybutyrate in blood and determining prevalence.

PubMed

Compton, C W R; Young, L; McDougall, S

2015-09-01

Firstly, to define, in dairy cows in the first 5 weeks post-calving fed a predominantly pasture-based diet, cut-points of concentrations of beta-hydroxybutyrate (BHBA) in blood, above which there were associations with purulent vaginal discharge (PVD), reduced pregnancy rates (PR) and decreased milk production, in order to better define subclinical ketosis (SCK) in such cattle; and secondly, to determine the prevalence, incidence and risk factors for SCK. An observational field study was conducted in 565 cows from 15 spring-calving and predominantly pasture-fed dairy herds in two regions of New Zealand during the 2010- 2011 dairy season. Within each herd, a cohort of randomly selected cows (approximately 40 per herd) was blood sampled to determine concentrations of BHBA on six occasions at weekly intervals starting within 5 days of calving. The key outcome variables were the presence/absence of PVD at 5 weeks post-calving, PR after 6 weeks (6-week PR) and after the completion of the breeding season (final PR), and mean daily milk solids production. Two cut-points for defining SCK were identified: firstly concentration of BHBA in blood≥1.2 mmol/L within 5 days post-calving, which was associated with an increased diagnosis of PVD (24 vs. 8%); and secondly concentration of BHBA in blood≥1.2 mmol/L at any stage within 5 weeks post-calving, which was associated with decreased 6-week PR (78 vs. 85%). The mean herd-level incidence of SCK within 5 weeks post-calving was 68 (min 12; max 100)% and large variations existed between herds in peak prevalence of SCK and the interval post-calving at which such peaks occurred. Cows>8 years of age and cows losing body condition were at increased risk of SCK within 5 weeks of calving. Cows with concentration of BHBA in blood≥1.2 mmol/L in early lactation had a higher risk of PVD and lower 6-week PR. Cow and herd-level prevalence of SCK varied widely in early lactation. Subclinical ketosis is common and is significantly associated with reproductive performance in mainly pasture-fed New Zealand dairy cattle. Controlling SCK may therefore result in improvements in herd reproductive performance. However considerable variation exists among herds in the incidence of SCK and in the timing of peak prevalence which means that herd-specific monitoring programmes are required to define herd SCK status accurately.

Materials Coating Techniques

DTIC Science & Technology

1980-03-01

applications from decorative to utilitarian over significant segments of the engineering, chemical, nuclear , microelectronics, and related Industries. PVD...Thermal-control coating. Boron 2430 Cermet component, nuclear shielding and controlrod material; Carbide wear- and temperature-resistant. Calcium...Zirconium Oxide (Hafnia-Pree � Thermal-barrier coatings for nuclear applications. Lime Stabi!Aed) Zirconium 2563 Resistant to high-temperature

The Winter Olympics--On Ice.

ERIC Educational Resources Information Center

Hoover, Barbara G.

1998-01-01

Describes several science activities designed around the upcoming Winter Olympics ice skating events which demonstrate the scientific principles behind the sport. Students learn that increasing the pressure on ice will lead to the ice melting, the principle involved in the spinning swing, and the technology of skates and skating outfits. (PVD)

Young in Mind.

ERIC Educational Resources Information Center

Miller, Mary K.

1998-01-01

According to experts, relatively minor memory lapses such as searching for misplaced car keys are perfectly normal but there are things that people can do to keep their minds agile and their memories alive. Discusses lifestyles and techniques used by seniors dedicated to exercising their minds. Also explores the science of memory and aging. (PVD)

Making an Ice Core.

ERIC Educational Resources Information Center

Kopaska-Merkel, David C.

1995-01-01

Explains an activity in which students construct a simulated ice core. Materials required include only a freezer, food coloring, a bottle, and water. This hands-on exercise demonstrates how a glacier is formed, how ice cores are studied, and the nature of precision and accuracy in measurement. Suitable for grades three through eight. (Author/PVD)

Developing a Global Environmental Perspective in the School Curriculum in India: An Exploratory Study.

ERIC Educational Resources Information Center

Sharma, Anjali

1997-01-01

Argues that atmospheric pollution, ozone depletion, and marine pollution are more prominent in the developed world than in developing countries. Emphasizes the need to reorient the Indian school curriculum from a national perspective to promote global environmental perspectives in diverse subject areas. (PVD)

Summing Certain p-Series.

ERIC Educational Resources Information Center

Fay, Temple H.

1997-01-01

Presents an exercise suitable for beginning calculus students that may give insight into series representations and allow students to see some elementary application of these representations. The Fourier series is used to approximate by taking sums of trigonometric functions of the form sin(ns) and cos(nx) for n is greater than or = zero. (PVD)

PHYSICAL VAPOR DEPOSITION OF TANTALUM ON GUN BARREL STEEL (SYSTEMS ANLAYSIS BRANCH, SUSTAINABLE TECHNOLOGY DIVISION, NRMRL)

EPA Science Inventory

This project entails the development of an alternative technology for plating gun barrel steel to replace the process electroplating of chrome (Cr-electroplate) with physical vapor deposition of tantalum (Ta-PVD). Developed by Benet Laboratory at Watervliet Arsenal, this project'...

Finding Your Way in the Legislation Maze: How To Pass Legislation in Your State.

ERIC Educational Resources Information Center

Gross, Steve

1997-01-01

Offers tips for developing and passing legislation that would protect animals. Recommends being an authority on the issue, researching current laws, recognizing support groups and lobbyists, and knowing key legislative players. Contains a description of laws passed in the state of Illinois. (PVD)

Teaching the Rock Cycle with Ease.

ERIC Educational Resources Information Center

Bereki, Debra

2000-01-01

Describes a hands-on lesson for teaching high school students the concept of the rock cycle using sedimentary, metamorphic, and igneous rocks. Students use a rock cycle diagram to identify pairs of rocks. From the rock cycle, students explain on paper how their first rock became the second rock and vice versa. (PVD)

Janice VanCleave's World: Trapper.

ERIC Educational Resources Information Center

VanCleave, Janice

2000-01-01

Introduces young children to the safe study of insects and promotes respect for the study specimen. Children craft insects out of marshmallows, toothpicks, and cardboard and practice using a clear plastic cup to collect and observe insects through a magnifying lens. With their new skills, they can move on to studying real insects. (PVD)

Zone compensated multilayer laue lens and apparatus and method of fabricating the same

DOEpatents

Conley, Raymond P.; Liu, Chian Qian; Macrander, Albert T.; Yan, Hanfei; Maser, Jorg; Kang, Hyon Chol; Stephenson, Gregory Brian

2015-07-14

A multilayer Laue Lens includes a compensation layer formed in between a first multilayer section and a second multilayer section. Each of the first and second multilayer sections includes a plurality of alternating layers made of a pair of different materials. Also, the thickness of layers of the first multilayer section is monotonically increased so that a layer adjacent the substrate has a minimum thickness, and the thickness of layers of the second multilayer section is monotonically decreased so that a layer adjacent the compensation layer has a maximum thickness. In particular, the compensation layer of the multilayer Laue lens has an in-plane thickness gradient laterally offset by 90.degree. as compared to other layers in the first and second multilayer sections, thereby eliminating the strict requirement of the placement error.

Micromechanical Properties of Nanostructured Clay-Oxide Multilayers Synthesized by Layer-by-Layer Self-Assembly.

PubMed

Hou, Dongwei; Zhang, Guoping; Pant, Rohit Raj; Wei, Zhongxin; Shen, Shuilong

2016-11-08

Clay-based nanostructured multilayers, such as clay-polymer multilayers and clay-oxide multilayers, have attracted growing attention owing to their remarkable mechanical properties and promising application in various fields. In this paper, synthesis of a new kind of nanostructured clay-oxide multilayers by layer-by-layer self-assembly was explored. Nano-mechanical characterization of 18 clay-based multilayer samples, prepared under as-deposited (i.e., air-dried) and annealing conditions at 400 °C/600 °C with different precursor cations and multilayer structure, were carried out using nanoindentation testing, atomic force microscopy (AFM), and X-ray diffraction (XRD). The influencing factors, including as-deposited and annealing conditions and clay concentrations on the mechanical properties were analyzed. Results show that all of the multilayers exhibit high bonding strength between interlayers. Higher modulus and hardness of clay-based multilayers were obtained with lower clay concentrations than that with higher clay concentrations. Different relationships between the modulus and hardness and the annealing temperature exist for a specific type of clay-oxide multilayer. This work offers the basic and essential knowledge on design of clay-based nanostructured multilayers by layer-by-layer self-assembly.

Method to adjust multilayer film stress induced deformation of optics

DOEpatents

Spiller, Eberhard A.; Mirkarimi, Paul B.; Montcalm, Claude; Bajt, Sasa; Folta, James A.

2000-01-01

Stress compensating systems that reduces/compensates stress in a multilayer without loss in reflectivity, while reducing total film thickness compared to the earlier buffer-layer approach. The stress free multilayer systems contain multilayer systems with two different material combinations of opposite stress, where both systems give good reflectivity at the design wavelengths. The main advantage of the multilayer system design is that stress reduction does not require the deposition of any additional layers, as in the buffer layer approach. If the optical performance of the two systems at the design wavelength differ, the system with the poorer performance is deposited first, and then the system with better performance last, thus forming the top of the multilayer system. The components for the stress reducing layer are chosen among materials that have opposite stress to that of the preferred multilayer reflecting stack and simultaneously have optical constants that allow one to get good reflectivity at the design wavelength. For a wavelength of 13.4 nm, the wavelength presently used for extreme ultraviolet (EUV) lithography, Si and Be have practically the same optical constants, but the Mo/Si multilayer has opposite stress than the Mo/Be multilayer. Multilayer systems of these materials have practically identical reflectivity curves. For example, stress free multilayers can be formed on a substrate using Mo/Be multilayers in the bottom of the stack and Mo/Si multilayers at the top of the stack, with the switch-over point selected to obtain zero stress. In this multilayer system, the switch-over point is at about the half point of the total thickness of the stack, and for the Mo/Be--Mo/Si system, there may be 25 deposition periods Mo/Be to 20 deposition periods Mo/Si.

Magnetic multilayer structure

DOEpatents

Herget, Philipp; O'Sullivan, Eugene J.; Romankiw, Lubomyr T.; Wang, Naigang; Webb, Bucknell C.

2016-07-05

A mechanism is provided for an integrated laminated magnetic device. A substrate and a multilayer stack structure form the device. The multilayer stack structure includes alternating magnetic layers and diode structures formed on the substrate. Each magnetic layer in the multilayer stack structure is separated from another magnetic layer in the multilayer stack structure by a diode structure.

Magnetic multilayer structure

DOEpatents

Herget, Philipp; O'Sullivan, Eugene J.; Romankiw, Lubomyr T.; Wang, Naigang; Webb, Bucknell C.

2017-03-21

A mechanism is provided for an integrated laminated magnetic device. A substrate and a multilayer stack structure form the device. The multilayer stack structure includes alternating magnetic layers and diode structures formed on the substrate. Each magnetic layer in the multilayer stack structure is separated from another magnetic layer in the multilayer stack structure by a diode structure.

Numerical simulation and experiment on multilayer stagger-split die.

PubMed

Liu, Zhiwei; Li, Mingzhe; Han, Qigang; Yang, Yunfei; Wang, Bolong; Sui, Zhou

2013-05-01

A novel ultra-high pressure device, multilayer stagger-split die, has been constructed based on the principle of "dividing dies before cracking." Multilayer stagger-split die includes an encircling ring and multilayer assemblages, and the mating surfaces of the multilayer assemblages are mutually staggered between adjacent layers. In this paper, we investigated the stressing features of this structure through finite element techniques, and the results were compared with those of the belt type die and single split die. The contrast experiments were also carried out to test the bearing pressure performance of multilayer stagger-split die. It is concluded that the stress distributions are reasonable and the materials are utilized effectively for multilayer stagger-split die. And experiments indicate that the multilayer stagger-split die can bear the greatest pressure.

MoRu/Be multilayers for extreme ultraviolet applications

DOEpatents

Bajt, Sasa C.; Wall, Mark A.

2001-01-01

High reflectance, low intrinsic roughness and low stress multilayer systems for extreme ultraviolet (EUV) lithography comprise amorphous layers MoRu and crystalline Be layers. Reflectance greater than 70% has been demonstrated for MoRu/Be multilayers with 50 bilayer pairs. Optical throughput of MoRu/Be multilayers can be 30-40% higher than that of Mo/Be multilayer coatings. The throughput can be improved using a diffusion barrier to make sharper interfaces. A capping layer on the top surface of the multilayer improves the long-term reflectance and EUV radiation stability of the multilayer by forming a very thin native oxide that is water resistant.

Prevalence of purulent vaginal discharge in dairy herds depends on timing but not method of detection

USDA-ARS?s Scientific Manuscript database

A review of existing literature was conducted to determine the prevalence of purulent vaginal discharge (PVD) in dairy herds around the world and detection methodologies that influence prevalence estimates. Four databases (PubMed, Google Scholar, Web of Science, and Scopus) were queried with the sea...

Gold Rush!

ERIC Educational Resources Information Center

Brahier, Daniel J.

1997-01-01

Describes a mathematical investigation of gold--how it is weighed, stored, used, and valued. For grades 3-4, children estimate the value of treasure chests filled with gold coins and explore the size and weight of gold bars. Children in grades 5-6 explore how gold is mined and used, and how the value of gold changes over time. (PVD)

Using Apple Peel Sections To Study Plant Cells and Water Relations.

ERIC Educational Resources Information Center

Silvius, John E.; Eckart, Christopher P.

1997-01-01

Suggests the cells of an apple peel as a plant species that can further enhance the plant cell laboratory. Describes the structure of apple peel cells and the benefits of including them in studies of plant cells. Suggests questions to stimulate further investigations for open-ended laboratories or independent studies. (PVD)

A Simple Formula for Quantiles on the TI-82/83 Calculator.

ERIC Educational Resources Information Center

Eisner, Milton P.

1997-01-01

The concept of percentile is a fundamental part of every course in basic statistics. Many such courses are now taught to students and require them to have TI-82 or TI-83 calculators. The functions defined in these calculators enable students to easily find the percentiles of a discrete data set. (PVD)

Nutrition in the prevention of Coronary Heart Disease and the management of lipoprotein disorders

USDA-ARS?s Scientific Manuscript database

Cardiovascular disease (CVD) is comprised of coronary heart disease (CHD), stroke, and peripheral vascular disease (PVD). CVD is caused by progressive narrowing and blockage of arteries supplying the heart, brain, and other tissues and organs. CVD is the leading cause of death and disability in our ...

iMAST FY2007 Annual Report

DTIC Science & Technology

2007-01-01

laser cladding techniques. Customer: COMSUBPAC NAVSEASYSCOM Pearl Harbor Naval Shipyard...motion device to laser clad and re-dimension the affected tube to original specifications. Benefits: ° Reduce life cycle costs of tube...coatings via cold gas dynamic spraying and EB–PVD ° Spray-formed HT aluminum alloys ° Localized laser HT and cladding for wear

Charles H. Winston and Confederate Sulfuric Acid.

ERIC Educational Resources Information Center

Riethmiller, Steven

1995-01-01

Describes the invention and use of a sulfuric acid chamber by Charles Henry Winston during the Civil War. This invention helped supply munitions for the South. Winston, who was President of the Richmond Female Institute in Virginia, constructed the chamber at his farm and was granted a patent by the Confederate Patent Office in 1863. (PVD)