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Sample records for er implanted si

  1. Lattice sites and damage annealing of implanted Tm and Er in Si

    CERN Document Server

    Wahl, U; De Wachter, J H; Langouche, G; Marques, J G; Moons, R; Vantomme, A

    1997-01-01

    We have studied the lattice sites of Er in CZ Si single crystals by using conversion electron emission channeling from the isotope $^{167m}$Er (2.28 s) which is the decay product of radioactive $^{167}$Tm (9.25 d). Following 60 keV implantation of $^{167}$Tm at a dose of 4 $\\times 10^{13}$ cm$^{-2}$ and annealing at 600°C, more than 90% of $^{167m}$Er is found close to tetrahedral insterstitial (T) sites. The tetrahedral fraction of $^{167m}$Er decreases considerably after 10 min annealing at 800°C and above. We attribute this to the onset of diffusion of the parent $^{167}$Tm and its trapping at other defects, presumably oxygen atoms or clusters of Tm/Er.

  2. Direct evidence for stability of tetrahedral interstitial Er in Si up to 900$^{\\circ}$C

    CERN Document Server

    Wahl, U; Langouche, G; Marques, J G; Vantomme, A

    1997-01-01

    Conversion electron emission channeling from the isotope $^{167m}$Er (2.28 s), which is the decay product of radioactive $^{167}$Tm (9.25 d), offers a means of monitoring the lattice sites of Er in single crystals. We have used this method to determine the lattice location of $^{167m}$Er in Si directly following room temperature implantation of $^{167}$Tm, after subsequent annealing steps, and also in situ during annealing up to 900°C. Following the recovery of implantation damage around 600°C, about 90% of Er occupies near-tetrahedral interstitial sites in both FZ and CZ Si. While in FZ Si $^{167m}$Er was found to be stable on these sites even at 900°C, the tetrahedral Er fraction in CZ Si decreased considerably after annealing for 10 min at 800°C and above.

  3. Local structure and bonding of Er in GaN: A contrast with Er in Si

    Energy Technology Data Exchange (ETDEWEB)

    Citrin, P. H. [Bell Labs, Lucent Technologies, Murray Hill, New Jersey 07974 (United States); Northrup, P. A. [Bell Labs, Lucent Technologies, Murray Hill, New Jersey 07974 (United States); Birkhahn, R. [University of Cincinnati, Nanoelectronics Laboratory, Cincinnati, Ohio 45221 (United States); Steckl, A. J. [University of Cincinnati, Nanoelectronics Laboratory, Cincinnati, Ohio 45221 (United States)

    2000-05-15

    X-ray absorption measurements from relatively high concentrations of Er (>0.1 at. %) doped in GaN films show that Er occupies the Ga site with an unprecedentedly short Er-N bond length. Electroluminescence intensities from these GaN:Er films correlate with the concentration of Er atoms that replace Ga, not with the abundantly present O impurities in the host. Simple chemical concepts are used to explain each of these results and their striking difference from those obtained for Er-doped Si. (c) 2000 American Institute of Physics.

  4. On the role of heterolayer relaxation in luminescence response of Si/SiGe:Er structures

    Energy Technology Data Exchange (ETDEWEB)

    Krasilnikova, Ludmila; Stepikhova, Margarita; Drozdov, Yurij; Krasilnik, Zakharii [Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, 603950 Nizhny Novgorod (Russian Federation); Chalkov, Vadim; Shengurov, Vladimir [Physico-Technical Research Institute, Nizhny Novgorod State University, Gagarin Ave. 23, 603950 Nizhny Novgorod (Russian Federation)

    2011-03-15

    In this contribution we discuss the luminescence properties of Si/Si{sub 1-x}Ge{sub x}:Er/Si structures being of interest for a laser realization. The influence of the strain relaxation processes that take place in such kind of structures on their photoluminescence response at 1.54 {mu}m has been analyzed. The studies were performed for Si/Si{sub 1-x}Ge{sub x}:Er/Si structures with the different thickness of Si{sub 1-x}Ge{sub x}:Er layers, and consequently the degree of strain relaxation. It is shown that the structural defects arising in Si/Si{sub 1-x}Ge{sub x}:Er/Si structures due to the relaxation play only negligible role in their photoluminescence response. The contribution of the structural defects in the photoluminescence response at 1.54 {mu}m became apparent only in thin partially relaxed Si/Si{sub 1-x}Ge{sub x}:Er/Si structures, the photoluminescence spectra of which are represented by the broad ''defect related'' lines. Intense photoluminescence related with the optically active Er centers of different types was observed for the strained and completely relaxed Si/Si{sub 1-x}Ge{sub x}:Er/Si structures containing thick (d > 1 {mu}m) Si{sub 1-x}Ge{sub x}:Er layers. The external quantum efficiency of these structures reaches the value of 6.3 x 10{sup -5} at T =77 K. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. Simulations of Proton Implantation in Silicon Carbide (SiC)

    Science.gov (United States)

    2016-03-31

    philip.feng@case.edu Abstract: We report on exploratory research effort with preliminary results on investigating fundamental radiation effects in...of implanting protons (hydrogen ions, H+) into SiC thin layers on silicon (Si) substrate, and explore the ion implantation conditions that are...create SiC-on-insulator (SiC-on-SiO2) films and structures [4,5]. It is important to understand and control the implantation depth. Presented here

  6. Expression of ER-α and ER-β during peri-implantation period in uterus is essential for implantation and decidualization in golden hamster.

    Science.gov (United States)

    Kumar, Randhir; Yadav, Akhilesh; Pakrasi, P L

    2017-02-01

    The role of estrogen in embryo implantation in golden hamster (Mesocricetus auratus) is still ambiguous. In order to clarify it, we investigated the spatial distribution and expression of estrogen receptors, ER-α and ER-β in the uterus of pregnant hamster during peri-implantation period and identified the effect of estrogen receptor antagonist ICI-182,780 on the embryo implantation. We performed in vivo experiments on early pregnant hamsters involving treatment with ICI-182,780, an estrogen receptor antagonist. Immunohistochemistry, western blot analysis and quantitative PCR were employed to evaluate the spatio-temporal distribution and expression of ER-α and ER-β in the uterus of normal early pregnant and treated hamsters. Results showed that embryo implantation was completely absent in ICI-182,780 treated uterine horn while, normal implantation occurred in control and vehicle treated horns. Both the receptors were differentially expressed in the uterus of hamster from day 1 (D1) to day7 (D7). In contrast, treated horns without any implantation site showed no trace of any receptors. Protein and mRNA expression of both the receptors were high around the day of implantation while, ER-β expression was up-regulated on D7 of embryo implantation. P value˂0.05 is considered significant. Spatio-temporal expression of ERs in the uterus during peri-implantation period have crucial role for endometrium receptivity and implantation in hamster. Recurrent implantation failure is the devastating problem among the desirable couple and is mainly due to defect in endometrium receptivity. This study may provide a new insight to manage the problem of idiopathic infertility. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Formation of Si/SiC multilayers by low-energy ion implantation and thermal annealing

    NARCIS (Netherlands)

    Dobrovolskiy, S.; Yakshin, A.E.; Yakshin, Andrey; Tichelaar, F.D.; Verhoeven, J.; Louis, E.; Louis, Eric; Bijkerk, Frederik

    2010-01-01

    Si/SiC multilayer systems for XUV reflection optics with a periodicity of 10–20 nm were produced by sequential deposition of Si and implantation of 1 keV View the MathML source ions. Only about 3% of the implanted carbon was transferred into the SiC, with a thin, 0.5–1 nm, buried SiC layer being

  8. The new ternary silicide ErCo{sub 3}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Dzevenko, Mariya; Bigun, Inna [Ivan Franko National Univ., Lviv (Ukraine). Dept. of Analytical Chemistry

    2014-03-15

    The new ternary silicide ErCo{sub 3}Si{sub 2} adopts the ErRh{sub 3}Si{sub 2} structure type (space group Imma, Pearson code oI24, Z = 4, a = 6.950(1), b = 9.020(2), c = 5.230(1) A, R{sub 1} = 0.0565, wR{sub 2} = 0.0355, 253 F{sup 2} values, 23 variables). It is a deformation derivative of the CeCo{sub 3}B{sub 2} structure type. The coordination of the Er atom shows a normal 20-vertex polyhedron [Er(Si{sub 6}Co{sub 12}Er{sub 2})]. The two similar coordination polyhedra of Co are a distorted icosahedron [Co(Si{sub 4}Co{sub 4}Er{sub 4})], and a distorted icosahedron with one capped face [Co(Si{sub 4}Co{sub 5}Er{sub 4})]. The Si atom is surrounded by the polyhedron [Si(Co{sub 6}Si{sub 2}Er{sub 3})]. (orig.)

  9. Modelling of ion implantation in SiC crystals

    Energy Technology Data Exchange (ETDEWEB)

    Chakarov, Ivan [SILVACO International, 4701 Patrick Henry Drive, Building 2, Santa Clara, CA 95054 (United States)]. E-mail: ivan.chakarov@silvaco.com; Temkin, Misha [SILVACO International, 4701 Patrick Henry Drive, Building 2, Santa Clara, CA 95054 (United States)

    2006-01-15

    An advanced electronic stopping model for ion implantation in SiC has been implemented within the binary collision approximation. The model has been thoroughly tested and validated for Al implantation into 4H-, 6H-SiC under different initial implant conditions. A very good agreement between calculated and experimental profiles has been achieved. The model has been integrated in an industrial technology CAD process simulator.

  10. Improving Passivation Process of Si Nanocrystals Embedded in SiO2 Using Metal Ion Implantation

    Directory of Open Access Journals (Sweden)

    Jhovani Bornacelli

    2013-01-01

    Full Text Available We studied the photoluminescence (PL of Si nanocrystals (Si-NCs embedded in SiO2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm inside the SiO2 achieving a robust and better protected system. After metal ion implantation (Ag or Au, and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H2/N2 and Ar to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

  11. Effect of radiation damage on luminescence of erbium-implanted SiO sub 2 /Si studied by slow positron beam

    CERN Document Server

    Kawasuso, A; Hirata, K; Sekiguchi, T; Kobayashi, Y; Okada, S

    2000-01-01

    The effect of damage on 1.54 mu m luminescence for 30 keV-Er-implanted SiO sub 2 films has been studied by positron annihilation and cathodoluminescence. It was found that S-parameter in the films decreased after implantation, indicating the suppression of positronium formation. The luminescence appeared with the recovery of the S-parameter after 600 deg. C annealing. The intensity reached a maximum at 900 deg. C annealing whereas the S-parameter did not change significantly. It seems that most damages recover at 600 deg. C and thereafter Er ions transform to an optically active state at 900 deg. C.

  12. Formation of nanocrystalline CrSi 2 layers in Si by ion implantation and pulsed annealing

    Science.gov (United States)

    Batalov, R. I.; Bayazitov, R. M.; Valeev, V. F.; Galkin, N. G.; Goroshko, D. L.; Galkin, K. N.; Chusovitin, E. A.; Gaiduk, P. I.; Ivlev, G. D.; Gatskevich, E. I.

    In this work buried nanocrystalline CrSi2 layers were synthesized by ion implantation, pulsed annealing and MBE. The structural, optical and thermoelectrical properties of CrSi2 layers were studied by methods of SEM, TEM, RBS, PL and Seebeck coefficient measurements. The characteristic features of pulsed nanosecond annealing of Cr-implanted Si and epitaxial growth of triple Si/nc-CrSi2/Si heterostructures were established. It is shown that grown Si/nc-CrSi2/Si heterostructures, which preliminary implanted with the high-dose (ϕ = 6 × 1016cm-2) of Cr+ ions, have the noticeable low temperature (T = 10 - 100 K) photoluminescence signal at 1450-1600 nm and the large Seebeck coefficient (-(60-300) μV/K) in the temperature range of T = 340 - 415 K.

  13. Er sensitization by a thin Si layer: Interaction-distance dependence

    DEFF Research Database (Denmark)

    Julsgaard, Brian; Lu, Ying-Wei; Jensen, Rasmus Vincentz Skougaard

    2011-01-01

    From photoluminescence measurements on sensitized erbium in a-Si/SiO2:Er/SiO2 multilayers, we determine the characteristic interaction length of the sensitization process from the silicon-layer sensitizer to the erbium-ion receiver to be 0.22±0.02 nm. By using sufficiently low temperatures...

  14. Photoemission study of the initial stage of Er/Si(100) interface formation

    CERN Document Server

    Chen Gang; Li Zhe Shen; Wang Xun

    2002-01-01

    The initial stage of Er/Si(100) interface formation has been investigated by using synchrotron radiation photoelectron spectroscopy combined with low-energy electron diffraction. Both the valence band and the core level peaks of the Si photoemission spectra shift rigidly with increasing Er coverage in the submonolayer region. Upon depositing 0.6 monolayers of Er on the Si(100) surface at room temperature, the surface Fermi level is ultimately pinned at 0.29 eV above its initial value, which is equivalent to a Schottky barrier height of 0.67 eV. No evidence is found for the formation of Er silicides at the as-deposited surfaces. Annealing of the Er-covered Si(100) surfaces at 600 deg. C results in the appearance of a new peak located 1.2 eV below the Si 2p peak, indicating the presence of some sort of Er silicide. Meanwhile, the Er 4f spectrum measured for samples upon annealing exhibits a well-resolved fine structure, implying that only monospecies of Er silicide may exist on the surface.

  15. Implant Surface Temperature Changes during Er:YAG Laser Irradiation with Different Cooling Systems.

    Directory of Open Access Journals (Sweden)

    Abbas Monzavi

    2014-04-01

    Full Text Available Peri-implantitis is one of the most common reasons for implant failure. Decontamination of infected implant surfaces can be achieved effectively by laser irradiation; although the associated thermal rise may cause irreversible bone damage and lead to implant loss. Temperature increments of over 10ºC during laser application may suffice for irreversible bone damage.The purpose of this study was to evaluate the temperature increment of implant surface during Er:YAG laser irradiation with different cooling systems.Three implants were placed in a resected block of sheep mandible and irradiated with Er:YAG laser with 3 different cooling systems namely water and air spray, air spray alone and no water or air spray. Temperature changes of the implant surface were monitored during laser irradiation with a K-type thermocouple at the apical area of the fixture.In all 3 groups, the maximum temperature rise was lower than 10°C. Temperature changes were significantly different with different cooling systems used (P<0.001.Based on the results, no thermal damage was observed during implant surface decontamination by Er:YAG laser with and without refrigeration. Thus, Er:YAG laser irradiation can be a safe method for treatment of periimplantitis.

  16. Excitation mechanism of Er{sup 3+} in a-Si:H; Anregungsmechanismus von Er{sup 3+} in a-Si:H

    Energy Technology Data Exchange (ETDEWEB)

    Kuehne, H.

    2004-07-01

    The aim of this work is the examination of the optoelectronical material a-Si:H (Er). It is characterised in the good electronic properties of the a-Si:H and the emission wavelength of 1.5 micrometer of erbium which coincides with the absorbtion minimum of glasfibres. Photoluminescence measurements confirm the assumption that oxigen is necessary for the optical activation of Er{sup 3+} in addition to the symmetrical breaking of the crystal field. The flexible lattice of a-Si:H enables a high concentration of Erbium up to 5.10{sup 21}/cm{sup 3} with a quantum efficiency of the luminescence of 0.5-1.5.10{sup -4} at room temperature. Photoluminescence excitation and absorption measurements of a-Si:H (Er) show, that there is no direct excitation of the erbium ions because the absorption of the Er{sup 3+} ions is two orders of magnitude below the absorption of silicon. The excitation or the Er{sup 3+} ions takes place through the absorption in silicon with additional energy transfer to Erbium. Photoluminescence measurements are done in order to differentiate between the possible excitation channels, the intrinsic bond-bond channel and the excitation through defects. The different temperature dependence of the intensity of the intrinsic luminescence (77 K - 300 K >3 orders of magnitude) in comparison with the defect luminescence and the Erbium luminescence (both 1-1.5 orders of magnitude) shows that the energy transfer takes place over defects. Luminescence and absorption measurements with boron doped a-Si:H (Er) show no dependence of the Erbium luminescence in dependence of defect density or the electrical charge of the defects. The luminescence spectra show a break in the defect luminescence at 0.84 eV. This agrees with the first excited state of the Er{sup 3+} ion combined with a clearly smaller line width of the defect luminescence (0.18 eV in comparision with >0.3 eV in erbium free a-Si:H). This result shows the resonance of the energy transfer. The resonance is

  17. Fast dynamics of 1.5 μm photoluminescence in Er-doped SiO2 sensitized with Si nanocrystals

    NARCIS (Netherlands)

    Timmerman, D.; Saeed, S.; Gregorkiewicz, T.

    2011-01-01

    In order to investigate origin of fast photoluminescence at 1.5 μm reported to appear in Er-doped SiO2 sensitized with silicon nanocrystals, time-resolved photoluminescence measurements were compared between high temperature annealed Er-doped and Er-free samples. We confirm that this fast

  18. High-Density Er-Implanted GaN Optical Memory Devices

    Science.gov (United States)

    Lee, Boon K.; Chih-Jen Chi, Robert; Liang-Chiun Chao, David; Cheng, Ji; Yeong-Ning Chry, Irving; Beyette, Fred R., Jr.; Steckl, Andrew J.

    2001-07-01

    Upconversion emission has been obtained from Er-focused ion-beam (FIB) implanted GaN. Visible green emission at the 522- and 546-nm range were excited with infrared (IR) laser sources at either 840 or 1000 nm, or with both lasers simultaneously. By implanting closely spaced patterns with the FIB, we demonstrated the concept of storing data in Er-implanted GaN. Information stored as data bits consists of patterns of implanted locations as logic 1 and unimplanted locations as logic 0. The photon upconversion process in Er ions is utilized to read the stored information. This process makes use of the IR lasers to excite visible emission. The integrated upconversion emission power was measured to be ~40 pW when pumped by a 840-nm laser at 265 mW and by a 1000-nm laser at 208 mW. Patterns as small as 0.5 m were implanted and read. Three-dimensional optical memory based on rare-earth-doped semiconductors could in theory approach a storage capacity of 1012 bits /cm3 .

  19. Pseudopotential description of rare earths in oxides: The case of Er2Si2O7

    DEFF Research Database (Denmark)

    Lægsgaard, Jesper; Stokbro, Kurt

    2001-01-01

    The applicability of ultrasoft pseudopotentials to the problem of rare-earth incorporation in silicates is investigated using the compound Er2Si2O7 as a test case. It is found that density-functional theory within the generalized gradient approximation provides a good description of the structural...

  20. Electronic structure and optical properties of the HoCoSi and ErNiSi compounds

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, Yu. V.; Lukoyanov, A. V., E-mail: lukoyanov@imp.uran.ru; Kuz’min, Yu. I. [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Gupta, S.; Suresh, K. G. [Indian Institute of Technology, Department of Physics (India)

    2016-10-15

    The electronic structure and the optical properties of the HoCoSi and ErNiSi compounds are studied. Spin-polarized band calculations are performed in the local electron density approximation corrected for the strong electron–electron interactions in the 4f shell of a rare-earth ion (LSDA + U method [11]). The optical constants are measured by ellipsometry in a wide wavelength range, and the frequency dependences of a number of spectral parameters are determined. The calculated densities of states are used to interpret the structural features of the interband optical conductivities of the intermetallic compounds.

  1. Experimental characterization of monocrystalline Si targets implanted with Sb + ions

    Science.gov (United States)

    Labbani, R.; Serrar, H.; Baouni, L.

    2010-02-01

    Monocrystalline silicon targets were submitted to a beam of antimony ions. The Si(1 1 1) substrates were implanted at an energy of 120 keV, at room temperature, to a dose varying from 1×10 15 to 5×10 15 Sb + cm -2. To recover the radiation defects generated by Sb + ions, a thermal annealing was performed, at 900 °C for 30 min under very high vacuum. The study of antimony ion implantation in the monocrystalline silicon targets was performed by means of different experimental techniques: X-ray diffraction, optical and electrical measurements. The perturbations enhanced by Sb + ion implantation and the recovery of the damage were investigated with great interest. Although the selected techniques are not frequently applied to investigate such phenomena, they have provided important results. In as-implanted specimens, it was found that the radiation damage increased with the increase of antimony dose. After the annealing treatment, a good recovery of defects was obtained especially in the samples implanted with the low dose (i.e. 1×10 15 Sb + cm -2).

  2. Effect of the breakdown nature on Er-related electroluminescence intensity and excitation efficiency in Si:Er light emitting diodes grown with sublimation MBE technique

    Energy Technology Data Exchange (ETDEWEB)

    Shmagin, V.B.; Kuznetsov, V.P.; Remizov, D.Yu.; Krasil' nik, Z.F.; Krasil' nikova, L.V.; Kryzhkov, D.I

    2003-12-15

    The influence of the p-n junction breakdown mechanism on the Er{sup 3+} electroluminescence (EL) intensity and excitation efficiency (an intra 4f transition {sup 4}I{sub 13/2}{yields}{sup 4}I{sub 15/2} of Er{sup 3+} ion at the wavelength of 1.54 {mu}m) has been investigated in Si:Er light emitting diodes (LED) grown with sublimation molecular beam epitaxy (SMBE) method. It is shown that the avalanche LEDs are characterized by a greater Er{sup 3+} EL intensity and excitation efficiency compared with the tunnel LEDs. At the same time, an excessive advance into the avalanche breakdown parameter region leads to microplasma breakdown of the p-n junction, which causes a non-uniform distribution of the drive current density over p-n junction area and an appreciable decrease of the Er{sup 3+} EL intensity. Si:Er LEDs operating in mixed breakdown conditions seem to be more preferable for reaching maximal Er{sup 3+} EL intensity at room temperature, as they provide an optimum combination of high Er{sup 3+} EL excitation efficiency with the uniformity of the p-n junction breakdown.

  3. Nanocrystalline diamond in carbon implanted SiO{sub 2}.

    Energy Technology Data Exchange (ETDEWEB)

    Tsoi, K.A.; Prawer, S.; Nugent, K.W.; Walker, R. J.; Weiser, P.S. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1996-12-31

    Recently, it was reported that nanocrystalline diamond can be produced via laser annealing of a high dose C implanted fused quartz (SiO{sub 2}) substrate. The aim of this investigation is to reproduce this result on higher C{sup +} dose samples and the non-implanted silicon sample, as well as optimise the power range and annealing time for the production of these nanocrystals of diamond. In order to provide a wide range of laser powers the samples were annealed using an Ar ion Raman laser. The resulting annealed spots were analysed using scanning electron microscopy (SEM) and Raman analysis. These techniques are employed to determine the type of bonding produced after laser annealing has occurred. 4 refs., 5 figs.

  4. Advances in bone surgery: the Er:YAG laser in oral surgery and implant dentistry

    Directory of Open Access Journals (Sweden)

    Stefan Stübinger

    2010-06-01

    Full Text Available Stefan StübingerCompetence Center for Applied Biotechnology and Molecular Medicine, University of Zürich, Zürich, SwitzerlandAbstract: The erbium-doped yttrium aluminium garnet (Er:YAG laser has emerged as a possible alternative to conventional methods of bone ablation because of its wavelength of 2.94 μm, which coincides with the absorption peak of water. Over the last decades in several experimental and clinical studies, the widespread initial assumption that light amplification for stimulated emission of radiation (laser osteotomy inevitably provokes profound tissue damage and delayed wound healing has been refuted. In addition, the supposed disadvantage of prolonged osteotomy times could be overcome by modern short-pulsed Er:YAG laser systems. Currently, the limiting factors for a routine application of lasers for bone ablation are mainly technical drawbacks such as missing depth control and a difficult and safe guidance of the laser beam. This article gives a short overview of the development process and current possibilities of noncontact Er:YAG laser osteotomy in oral and implant surgery.Keywords: carbonization, laser osteotomy, ablation, dental implants

  5. Growth of DySi sub 2 layers on Si surface by high-current Dy-ion implantation

    CERN Document Server

    Cheng, X Q

    2003-01-01

    We report, in this paper, the synthesis of DySi sub 2 layers on Si surfaces by high-current Dy-ion implantation in Si wafers using a metal vapor vacuum arc ion source. It was found that the continuous DySi sub 2 layers could grow at a relatively low formation temperature of 190degC and that the surface morphology varied with the variation of the implantation parameters. The formation mechanism of the equilibrium DySi sub 2 phase as well as the continuous DySi sub 2 layer on Si surface is proposed in terms of ion beam heating and the effect of ion dose on the Dy-ion implantation process. (author)

  6. Implantation damage in heavy gas implanted 4H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Nicolaï, J., E-mail: julien.nicolai@univ-poitiers.fr [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Declémy, A. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France); Gilabert, E. [Centre d’Etude Nucléaire de Bordeaux-Gradignan, 33175 Gradignan Cedex (France); Beaufort, M.-F.; Barbot, J.-F. [Institut Pprime, CNRS, Université de Poitiers, ENSMA, UPR 3346, Département Physique et Mécanique des Matériaux, Bd Marie et Pierre Curie, BP 30179, 86962 Futuroscope Chasseneuil Cedex (France)

    2016-05-01

    Single crystals of SiC were implanted with heavy inert gases (Xe, Ar) at elevated temperatures (300–800 °C) and for a large range of fluence (1 × 10{sup 12}–1 × 10{sup 15} ions cm{sup −2}). Thermodesorption measurements suggest that gas is trapped by implantation-induced vacancy-type defects impeding any gas diffusion. The damage accumulation versus dose was studied through the tensile elastic strain determined by using X-ray diffraction. Results show that at low dose the strain is predictable via a thermally activated direct impact model. The low thermal activation energy at saturation suggests a dynamic recovery process dominated by the migration of interstitial-type defects as its relaxation during post thermal annealing. As compared with light-gas implantation the heavy-gas to defect ratio is low enhancing the formation of strongly perturbed zones rather than the formation of bubble precursors.

  7. A comparative study of 1.5 μm photoluminescence from (Er, Si) and (Er, Ge) co-sputtered with Al{sub 2}O{sub 3} on Si

    Energy Technology Data Exchange (ETDEWEB)

    Mayandi, J. [Department of Physics and Centre of Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048, Blindern, NO-0316 Oslo (Norway); Department of Materials Science, School of Chemistry, Madurai Kamaraj University, Madurai, Tamil Nadu 625 021 (India); Finstad, T.G., E-mail: terje.finstad@fys.uio.no [Department of Physics and Centre of Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048, Blindern, NO-0316 Oslo (Norway); Foss, S.; Galeckas, A. [Department of Physics and Centre of Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048, Blindern, NO-0316 Oslo (Norway); Stange, M. [SINTEF Materials and Chemistry, P.O. Box 124, Blindern, NO-0314 Oslo (Norway)

    2014-03-25

    Highlights: • An attempt to fabricate Si and Ge nanocrystals/nanoclusters in Al{sub 2}O{sub 3} matrix in Si substrates. • Co-doping of Er in Si and Ge sputtered with Al{sub 2}O{sub 3} matrix. • 1.5 μm intense luminescence is emitted from Er ion with presence of Si nanoclusters. • Quenching of luminescence due to the presence of Ge ions in the sputtered matrix. -- Abstract: We present a comparative study of the 1.54 μm photoluminescence (PL) from Al{sub 2}O{sub 3}:(Er, Si) and Al{sub 2}O{sub 3}:(Er, Ge) films co-sputtered on Si substrates using a composite target. The PL yield of Si- and Ge-doped films subjected to different thermal treatment in the range 500–1100 °C is referenced against that of a control Al{sub 2}O{sub 3}:(Er) structure. The Er-related emission reaches maximum upon annealing at 700 °C for the Al{sub 2}O{sub 3}:(Er, Si) and 500 °C for the Al{sub 2}O{sub 3}:(Er, Ge) films, in both cases decreasing at higher annealing temperatures. Ge co-doped films are found to be approximately 20 times less luminous than the reference Al{sub 2}O{sub 3}:(Er) structure, whereas Si co-doping leads to greatly enhanced emission at 1.54 μm. By adapting energy filtered transmission electron microscopy (EFTEM), the presence of ∼2 nm Si nanoclusters was revealed, whereas no indications of Ge clusters or crystals could be observed implying that mere presence of Ge in the Al{sub 2}O{sub 3} matrix can dramatically reduce the luminescence efficiency. We discuss the possible reasons for not forming the Ge nanoclusters in the Al{sub 2}O{sub 3} host and the apparent quenching of the Er-related emission.

  8. Influence of O and C co-implantation on the lattice site of Er in GaN

    CERN Document Server

    De Vries, Bart; Vantomme, A; Wahl, Ulrich; Rita, E M C; Alves, E; Lima-Lopes, Armandina Maria; Correia, J G

    2004-01-01

    The lattice location of low-dose implanted Er in GaN, GaN:O, and GaN:C was investigated using the emission channeling technique. The conversion electrons emitted by the probe isotope $^{167m}$Er give direct evidence that the majority (~90%) of Er atoms are located on substitutional Ga sites for all samples. Annealing up to 900 °C does not change these fractions, although it reduces the Er root-mean-square (rms) displacements. The only visible effect of oxygen or carbon doping is a small increase in the rms displacements with respect to the undoped sample.

  9. Optical performance of thin films produced by the pulsed laser deposition of SiAlON and Er targets

    Science.gov (United States)

    Camps, I.; Ramírez, J. M.; Mariscal, A.; Serna, R.; Garrido, B.; Perálvarez, M.; Carreras, J.; Barradas, N. P.; Alves, L. C.; Alves, E.

    2015-05-01

    We report the preparation and optical performance of thin films produced by pulsed laser deposition in vacuum at room temperature, by focusing an ArF excimer laser onto two separate targets: a commercial ceramic SiAlON and a metallic Er target. As a result of the alternate deposition Er:SiAlON films were formed. The as grown films exhibited an Er-related emission peaking at 1532 nm. The role of the PLD energy density during deposition on the final matrix film was investigated, in order to achieve an optimized matrix composition with enhanced optical properties, and its effect on the light emission performance.

  10. Gettering of Co in Si by high-energy B ion-implantation and by p/p+ epitaxial Si

    Science.gov (United States)

    Benton, J. L.; Boone, T.; Jacobson, D. C.; Rafferty, C. S.

    2000-12-01

    Detection and gettering of Co contamination in processed Si is an important issue in integrated circuit fabrication. In this work, Co was intentionally introduced into Si by ion implantation, and its diffusion monitored by secondary ion mass spectroscopy. The surface layer recombination lifetime in p/p+ epitaxial Si is unaffected by the Co at doses of 1×1011cm-2 or 1×1012cm-2. In the case of 2.5 MeV, 4×1014B/cm2 ion implanted bulk Si, two mechanisms for Co redistribution during high temperature furnace, 900 °C, 30 min, processing are evident. First, regions of high boron concentration provide gettering sites for Co contamination. Second, the final distribution of Co in Si reflects ion-implantation induced defect evolution during annealing. Both mechanisms will operate during device processing and will control the effect of the metal on the electrical properties of the Si.

  11. Swelling behaviour and TEM studies of SiC f/SiC composites after fusion relevant helium implantation

    Science.gov (United States)

    Scholz, H. W.; Frias Rebelo, A. J.; Rickerby, D. G.; Krogul, P.; Lee, W. E.; Evans, J. H.; Fenici, P.

    1998-10-01

    Helium implantation was carried out on SiC f/SiC (CVI) composites up to doses of 2500 appm, at temperatures of 1175 ± 50 K. In this paper the swelling behaviour of the implanted bending bars is reported. A significant differential swelling effect after the α-implantation was evidenced by the matrix jutting out with respect to the fibre ends, at the side surfaces of the implanted zone. A similar fibre shrinkage together with slight expansion of the matrix was already reported for neutron irradiated materials. However, after α-implantation this effect is enhanced by an increased swelling of the β-SiC matrix. These data are discussed in relation to microstructural observations by Transmission Electron Microscopy.

  12. RBS-study of GexSi1-x Compounds Formed by Variable Dose Ge Implantation into Si Wafers

    Directory of Open Access Journals (Sweden)

    Ramírez A.

    2002-01-01

    Full Text Available Amorphous and relaxed epitaxial GeSi films are prepared by Ge-implantation into Si(111 wafers of both 60 keV and 200 keV energetic Ge+-ions with appropriate dose, followed by post-implantation thermal annealing, comprising a single final annealing at a temperature of 900 °C. The implantation dose was varied between 10(14 and 10(17 atoms cm-2. Rutherford backscattering (RBS and channeling analysis was applied in order to explore the formation of a single crystalline Si-Ge compound layer, both prior and after the thermal treatment. The depth and the thickness of the implanted layer, as well as their molar composition and crystalline quality was determined, and it was found that a single crystalline Si-Ge alloy layer was created, with both depth and mole fraction depending on the ion energy and the ion dose.

  13. Investigation of various phases of Fe–Si structures formed in Si by low energy Fe ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Lakshantha, Wickramaarachchige J.; Dhoubhadel, Mangal S.; Reinert, Tilo; McDaniel, Floyd D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Rout, Bibhudutta, E-mail: bibhu@unt.edu [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Center for Advanced Research and Technology, University of North Texas, 3940 North Elm Street, Denton, TX 76207 (United States)

    2015-12-15

    The compositional phases of ion beam synthesized Fe–Si structures at two high fluences (0.50 × 10{sup 17} atoms/cm{sup 2} and 2.16 × 10{sup 17} atoms/cm{sup 2}) were analyzed using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The distribution of Fe implanted in Si was simulated using a dynamic simulation code (TRIDYN) incorporating target sputtering effects. The Fe depth profiles in the Si matrix were confirmed with Rutherford backscattering spectrometry (RBS) and XPS depth profiling using Ar-ion etching. Based on XPS binding energy shift and spectral asymmetry, the distribution of stable Fe–Si phases in the substrate was analyzed as a function of depth. Results indicate Fe implantation with a fluence of 0.50 × 10{sup 17} atoms/cm{sup 2} and subsequent thermal annealing produce mainly the β-FeSi{sub 2} phase in the whole thickness of the implanted region. But for the samples with a higher fluence Fe implantation, multiple phases are formed. Significant amount of Fe{sub 3}Si phase are found at depth intervals of 14 nm and 28 nm from the surface. Initially, as-implanted samples show amorphous Fe{sub 3}Si formation and further thermal annealing at 500 °C for 60 min formed crystalline Fe{sub 3}Si structures at the same depth intervals. In addition, thermal annealing at 800 °C for 60 min restructures the Fe{sub 3}Si clusters to form FeSi{sub 2} and FeSi phases.

  14. Optical Properties of Er in Er-Doped Zn2Si_0.5Ge_0.5O4 Waveguide Amplifiers

    Science.gov (United States)

    Banerjee, Siddhartha; Baker, Christopher C.; Steckl, Andrew J.; Klotzkin, David

    2005-03-01

    There is a growing need for compact, efficient integrated waveguide optical amplifiers for use in optoelectronic communication. Zn2Si_0.5Ge_0.5O4 (ZSG) doped with Er (ZSG-Er) is a promising new host material due to the high concentration of Er that can be incorporated and the high optical activity of the incorporated Er. In this paper, the absorption and emission cross sections of Er in ZSG-Er (to the authors' knowledge,for the first time) are measured both through photoluminescence spectra and direct gain and absorption measurements. Peak absorption and emission cross sections are about 3 x 10^-24 m? from a Landenburg-Fuchtbauer analysis of the photoluminescence spectra, comparable to measurements on other oxide-based glass amplifiers. The population statistics of the excited Er level, along with the excited-state lifetime, are determined through a novel frequency-domain method in which the spontaneous emission power at 1550 nm is measured as a function of frequency under a modulated 980-nm input. The determined lifetime of 2 ms is comparable to the 2.3 ms measured using a conventional pump-probe technique. The novel analysis technique yields the population statistics of the excited Er atoms and the lifetime of the excited Er state under given pumping conditions independent of the unknown and variable coupling in and out of the waveguide. This method predicts zero net gain at 70 mW, about what is observed. Comparison of calculated gain and absorption based on Er density and measured cross sections with measured gains suggest that only about 20%-30% of the Er in the material is optically active. A 4.7-cm-long sample demonstrated a signal enhancement of ~ 13 dB. Cavity characteristics were measured using an analysis of coherent reflection under no pumping. The facet reflectivity was determined to be 0.27, and the scattering/absorption loss was 1.05/cm, for a total distributed loss of 1.65/cm in a 4-cm cavity. These losses, compared with an estimated achievable gain

  15. Mechanism of quantum dot luminescence excitation within implanted SiO2:Si:C films.

    Science.gov (United States)

    Zatsepin, A F; Buntov, E A; Kortov, V S; Tetelbaum, D I; Mikhaylov, A N; Belov, A I

    2012-02-01

    Results of the investigation of photoluminescence (PL) mechanisms for silicon dioxide films implanted with ions of silicon (100 keV; 7 × 10(16) cm(-2)) and carbon (50 keV; 7 × 10(15)-1.5 × 10(17) cm(-2)) are presented. The spectral, kinetic and thermal activation properties of the quantum dots (Si, C and SiC) formed by a subsequent annealing were studied by means of time-resolved luminescence spectroscopy under selective synchrotron radiation excitation. Independent quantum dot PL excitation channels involving energy transfer from the SiO(2) matrix point defects and excitons were discovered. A resonant mechanism of the energy transfer from the matrix point defects (E' and ODC) is shown to provide the fastest PL decay of nanosecond order. The critical distances (6-9 nm) of energy transport between the bulk defects and nanoclusters were determined in terms of the Inokuti-Hirayama model. An exchange interaction mechanism is realized between the surface defects (E(s)'-centres) and the luminescent nanoparticles. The peculiarities of an anomalous PL temperature dependence are explained in terms of a nonradiative energy transfer from the matrix excitons. It is established that resonant transfer to the luminescence centre triplet state is realized in the case of self-trapped excitons. In contrast, the PL excitation via free excitons includes the stages of energy transfer to the singlet state, thermally activated singlet-triplet conversion and radiative recombination.

  16. Temperature-induced increase in erbium electroluminescence of epitaxially grown Si:Er diodes

    Energy Technology Data Exchange (ETDEWEB)

    Shmagin, V.B. [Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, 603950 Nizhny Novgorod (Russian Federation)], E-mail: shm@ipm.sci-nnov.ru; Lyutov, A.V.; Remizov, D.Yu.; Kudryavtsev, K.E.; Stepikhova, M.V.; Krasilnik, Z.F. [Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, 603950 Nizhny Novgorod (Russian Federation)

    2008-01-15

    Electroluminescence (EL) at 1.54 {mu}m of reverse biased Si:Er diodes grown by sublimation molecular-beam epitaxy has been investigated as a function of temperature in the range of 80-300 K. An erbium electroluminescence trend versus temperature is shown to be determined by the p-n junction breakdown mechanism: we observe the EL quenching in light emitting diodes (LEDs) exhibiting a tunnel p-n junction breakdown and EL increase with temperature in diodes exhibiting an avalanche one. LEDs exhibiting a mixed p-n junction breakdown show rather weak dependence of erbium EL on temperature. We connect the temperature-induced increase in erbium EL observed in the avalanche LEDs with increase in EL pumping efficiency due to improved p-n junction breakdown homogeneity at higher temperatures.

  17. UV-VIS-NIR luminescence properties of an intense 5d broadband sensitized Eu2SiS4:Er3+ suitable for solar spectral converter

    Science.gov (United States)

    Zhang, Gongguo; Cui, Qiuyu; Liu, Guodong

    2016-07-01

    A novel broadband sensitized near-infrared emitting phosphor, Eu2SiS4:Er3+, was developed as promising solar spectral converter for Si solar cells. Eu2SiS4:Er3+ has broadband absorptions ranging from 250 nm to 550 nm which can efficiently facilitate the UV-green part of the solar photon flux spectrum and exhibits intense NIR emission of Er3+, perfectly matching the maximum spectral response of Si solar cells. The NIR integrated emission intensity of Eu2SiS4:0.02Er3+ is 6.14 times as intense as that of a dual-mode solar spectral converter CaLaGa3S6O:0.01Ce3+, 0.06Pr3+. These results demonstrate that Eu2SiS4:Er3+ phosphor is a promising candidate used as solar spectral converter.

  18. Energy transfer between doubly doped Er3+, Tm3+and Ho3+ rare earth ions in SiO2 nanoparticles

    CSIR Research Space (South Africa)

    Dhlamini, MS

    2011-04-01

    Full Text Available ) colours were measured from both SiO2:Er3+,Tm3+ and SiO2:Ho3+,Tm3+ systems. The change in the intensities of the emission peaks in both the SiO2:Ho3+,Tm3+ and SiO2:Er3+,Tm3+ systems with the change in accelerating beam voltage is shown. Energy transfer from...

  19. Fabrication of high-quality strain relaxed SiGe(1 1 0) films by controlling defects via ion implantation

    Science.gov (United States)

    Kato, M.; Arimoto, K.; Yamanaka, J.; Nakagawa, K.; Sawano, K.

    2017-11-01

    We investigate effects of ion implantation on strain relaxation of SiGe(1 1 0) layers grown on Si(1 1 0) substrates. Ar+ or Si+ ion implantation is carried out before or after the SiGe growth. It is found that the strain relaxation of the SiGe(1 1 0) film is largely enhanced due to implantation-induced defects both for Ar and Si implantation. Particularly, the sample with Si implantation after the SiGe growth allows large strain relaxation and smaller surface roughness than Ar implantation. As a result, a 50-nm-thick Si0.79Ge0.21 or Si0.77Ge0.23(1 1 0) buffer layer with almost full relaxation and rms surface roughness below 0.5 nm was obtained. It is, therefore, expected that high-mobility strained Si/Ge(1 1 0) channels can be realized on the SiGe(1 1 0) relaxed buffer layers fabricated by Si implantation. It is also demonstrated that the local introduction of the implantation defects allows controlling of lateral strain states and dislocation generation, opening new concepts of engineering of both strain and surface orientation.

  20. Optical performance of thin films produced by the pulsed laser deposition of SiAlON and Er targets

    Energy Technology Data Exchange (ETDEWEB)

    Camps, I., E-mail: camps@io.cfmac.csic.es [Laser Processing Group, Instituto de Óptica, CSIC, C/Serrano 121, 28006 Madrid (Spain); Ramírez, J.M. [MIND-IN2UB, Departament d’Electrònica, Universitat de Barcelona, c/Martí i Franqués 1, 08028 Barcelona (Spain); Mariscal, A.; Serna, R. [Laser Processing Group, Instituto de Óptica, CSIC, C/Serrano 121, 28006 Madrid (Spain); Garrido, B. [MIND-IN2UB, Departament d’Electrònica, Universitat de Barcelona, c/Martí i Franqués 1, 08028 Barcelona (Spain); Perálvarez, M.; Carreras, J. [IREC, Fundació Privada Institut de Recerca en Energia de Catalunya (Spain); Barradas, N.P.; Alves, L.C. [C" 2TN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10, 2695-066 Bobadela (Portugal); Alves, E. [IPFN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10, 2695-066 Bobadela (Portugal)

    2015-05-01

    Highlights: • PLD production of Er-doped thin films from a low cost commercial SiAlON target. • The role of the ablation fluence on the composition, optical properties as well as on the light emission performance at 1.5 μm. • The optimized performance is obtained for the samples deposited at the higher used ablation energy density. Further improvement was achieved through annealing. - Abstract: We report the preparation and optical performance of thin films produced by pulsed laser deposition in vacuum at room temperature, by focusing an ArF excimer laser onto two separate targets: a commercial ceramic SiAlON and a metallic Er target. As a result of the alternate deposition Er:SiAlON films were formed. The as grown films exhibited an Er-related emission peaking at 1532 nm. The role of the PLD energy density during deposition on the final matrix film was investigated, in order to achieve an optimized matrix composition with enhanced optical properties, and its effect on the light emission performance.

  1. Decrease of Staphylococcal adhesion on surgical stainless steel after Si ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Braceras, Iñigo, E-mail: inigo.braceras@tecnalia.com [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Pacha-Olivenza, Miguel A. [CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Universidad de Extremadura, Departamento de Física Aplicada, Facultad de Ciencias, Av. Elvas s/n, 06006 Badajoz (Spain); Calzado-Martín, Alicia [Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Multigner, Marta [Centro Nacional de Investigaciones Metalúrgicas, CENIM-CSIC, Avda Gregorio del Amo 8, 28040 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Vera, Carolina [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Broncano, Luis Labajos-; Gallardo-Moreno, Amparo M. [Universidad de Extremadura, Departamento de Física Aplicada, Facultad de Ciencias, Av. Elvas s/n, 06006 Badajoz (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); González-Carrasco, José Luis [Centro Nacional de Investigaciones Metalúrgicas, CENIM-CSIC, Avda Gregorio del Amo 8, 28040 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Vilaboa, Nuria [Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); and others

    2014-08-15

    Highlights: • Si ion implantation of AISI 316LVM medical grade alloy might reduce bacterial adhesion and colonization. • Si ion implantation does not impair the attachment, viability and matrix maturation of human mesenchymal stem cells. • Nano-topography and surface chemistry changes account for the Si ion implantation induced effects. - Abstract: 316LVM austenitic stainless steel is often the material of choice on temporal musculoskeletal implants and surgical tools as it combines good mechanical properties and acceptable corrosion resistance to the physiologic media, being additionally relatively inexpensive. This study has aimed at improving the resistance to bacterial colonization of this surgical stainless steel, without compromising its biocompatibility and resistance. To achieve this aim, the effect of Si ion implantation on 316LVM has been studied. First, the effect of the ion implantation parameters (50 keV; fluence: 2.5–5 × 10{sup 16} ions/cm{sup 2}; angle of incidence: 45–90°) has been assessed in terms of depth profiling of chemical composition by XPS and nano-topography evaluation by AFM. The in vitro biocompatibility of the alloy has been evaluated with human mesenchymal stem cells. Finally, bacterial adhesion of Staphylococcus epidermidis and Staphylococcus aureus on these surfaces has been assessed. Reduction of bacterial adhesion on Si implanted 316LVM is dependent on the implantation conditions as well as the features of the bacterial strains, offering a promising implantable biomaterial in terms of biocompatibility, mechanical properties and resistance to bacterial colonization. The effects of surface composition and nano-topography on bacterial adhesion, directly related to ion implantation conditions, are also discussed.

  2. Transition metal swift heavy ion implantation on 4H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Ali, A. Ashraf; Kumar, J. [Crystal Growth Centre, Anna University, Chennai 600 025 (India); Ramakrishnan, V. [Indian Institute of Science Education and Research, Thiruvanthapuram (India); Asokan, K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

    2016-03-01

    This work reports on the realization of Quantum Ring (QR) and Quantum Dot (QD) like structures on 4H-SiC through SHI implantation and on their Raman studies. 4H-SiC is SHI implanted with Transition Metal (TM) Ni ion at different fluences. It is observed that a vibrational mode emerges as the result of Ni ion implantation. The E{sub 2} (TO) and the A{sub 1} (LO) are suppressed as the fluence increases. In this paper Raman and AFM studies have been performed at room temperature and the queer anomalies are addressed so new devices can be fabricated.

  3. Pulsed laser irradiation-induced microstructures in the Mn ion implanted Si

    Energy Technology Data Exchange (ETDEWEB)

    Naito, Muneyuki, E-mail: naito22@center.konan-u.ac.jp [Department of Chemistry, Konan University, Okamoto, Higashi-Nada, Kobe, Hyogo 658-8501 (Japan); CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Yamada, Ryo; Machida, Nobuya [Department of Chemistry, Konan University, Okamoto, Higashi-Nada, Kobe, Hyogo 658-8501 (Japan); Koshiba, Yusuke; Sugimura, Akira; Aoki, Tamao; Umezu, Ikurou [Department of Physics, Konan University, Okamoto, Higashi-Nada, Kobe, Hyogo 658-8501 (Japan)

    2015-12-15

    We have examined microstructures induced by pulsed-laser-melting for the Mn ion implanted Si using transmission electron microscopy. Single crystalline Si(0 0 1) wafers were irradiated with 65 keV and 120 keV Mn ions to a fluence of 1.0 × 10{sup 16}/cm{sup 2} at room temperature. The ion beam-induced amorphous layers in the as-implanted samples were melted and resolidified by pulsed YAG laser irradiation. After laser irradiation with appropriate laser fluence, the surface amorphous layers recrystallize into the single crystalline Si. The Mn concentration becomes higher in the near-surface region with increasing the number of laser shots. The migrated Mn atoms react with Si atoms and form the amorphous Mn–Si in the Si matrix.

  4. Swelling and stacking fault formation in helium implanted SiC

    Energy Technology Data Exchange (ETDEWEB)

    Barbot, J.F., E-mail: jean.francois.barbot@univ-poitiers.fr [Institut Pprime, UPR3346, CNRS-Universite de Poitiers-ENSMA, Department of Material Sciences, SP2MI, Bd. M. et P. Curie, Teleport 2, BP 30179, F-86962 Futuroscope - Chasseneuil (France); Beaufort, M.F. [Institut Pprime, UPR3346, CNRS-Universite de Poitiers-ENSMA, Department of Material Sciences, SP2MI, Bd. M. et P. Curie, Teleport 2, BP 30179, F-86962 Futuroscope - Chasseneuil (France); Texier, M. [IM2NP Faculte des Sciences et Techniques, Campus de Saint Jerome, av. Escadrille Normandie Niemen, F-13397 Marseille Cedex (France); Tromas, C. [Institut Pprime, UPR3346, CNRS-Universite de Poitiers-ENSMA, Department of Material Sciences, SP2MI, Bd. M. et P. Curie, Teleport 2, BP 30179, F-86962 Futuroscope - Chasseneuil (France)

    2011-06-30

    Effects of annealing on surface swelling in helium implanted 4H-SiC were studied for different implant conditions. The significant increase of surface swelling observed upon high temperature annealing of samples implanted under severe implant conditions (high temperature and fluence) is observed to be concomitant with the growth of cavities and the formation of other extended defects in the highly damaged zone. Frank loops resulting from the drift of interstitials only form in the highly damaged zone. These loops promote the formation of Shockley partial dislocations leading to stacking fault pile-up. For less severe conditions of implantation, low temperature and fluence, the formation of dislocations is avoided upon post-annealing, and the recovery of swelling progressively occurs. Under intermediate conditions of implantation, the compensation between elastic recovery of the implantation-induced strain and the limited formation of cavities and interstitial-type clusters result in a constant swelling.

  5. The structural changes and optical properties of LiNbO3 after Er implantation using high ion fluencies

    Science.gov (United States)

    Macková, A.; Malinský, P.; Pupíková, H.; Nekvindová, P.; Cajzl, J.; Sofer, Z.; Wilhelm, R. A.; Kolitsch, A.; Oswald, J.

    2014-08-01

    The structural and compositional changes of LiNbO3 implanted with 190 keV Er+ ions into various crystallographic cuts with fluencies of 1 × 1016 and 5 × 1016 cm-2 were studied. The effect of post-implantation annealing at 1000 °C in oxygen atmosphere was also examined. Concentration depth profiles of implanted erbium, determined by Rutherford Backscattering Spectrometry (RBS), are broader than those from the SRIM simulation. The maximum erbium concentration (of up to 8 at.%) is observed at the depth of about 50 nm, for all crystal cuts. The structure of the implanted layers were characterised by RBS-channelling method. The lower relative number of disordered atoms in the crystalline matrix was observed in the lithium niobate (LN) implanted at a fluence of 1 × 1016 cm-2, where also the preferential position of the erbium in substitutional sites was observed when compared to the randomly distributed erbium in interstitial positions at a fluence of 5 × 1016 cm-2 after the annealing. Surface-morphology changes at the highest implantation fluencies were studied using Atomic Force Microscopy (AFM). Since we were interested in the relation between the structural changes and optical properties, erbium luminescence properties were measured in the region of 1440-1650 nm. The positive effect of post-implantation annealing on the luminescence properties caused by structural recovery was proved.

  6. An intense reddish-orange emitting Eu2SiS4:Er3+ for light emitting diodes

    Science.gov (United States)

    Zhang, Gongguo; Lu, Xifeng; Hu, Ang

    2017-09-01

    An intense reddish-orange phosphor, Eu2SiS4:Er3+, was developed. The photoluminescence excitation and emission spectra, the lifetime, and the concentration effect are investigated. The results show that an efficient energy transfer occurs from Eu2+ to Er3+, and its efficiency is about 81.0%. The phosphors exhibit an efficient broad absorption band and give reddish-orange emitting light with higher color purity. These results demonstrate that Er3+ ion with low 4f - 4f absorption efficiency can play a role of activator in narrow reddish-orange emitting phosphor, potentially useful in n-UV/blue GaN-based LED through efficient energy feeding by a strong excitation band of Eu2+.

  7. Identification of Λ -like systems in Er3+:Y2SiO5 and observation of electromagnetically induced transparency

    Science.gov (United States)

    Baldit, E.; Bencheikh, K.; Monnier, P.; Briaudeau, S.; Levenson, J. A.; Crozatier, V.; Lorgeré, I.; Bretenaker, F.; Le Gouët, J. L.; Guillot-Noël, O.; Goldner, Ph.

    2010-04-01

    Electromagnetically induced transparency (EIT) is reported in a solid-state material doped with erbium ions. In this paper we introduce the spectroscopic investigations we have conducted in order to identify the adequate Λ -like three-level systems in Er3+:Y2SiO5 crystal, relevant for the demonstration of EIT. These results pave the way for nonlinear and quantum optics applications based on EIT at the telecom wavelength around 1.5μm .

  8. Microstructural and magnetic study of Fe-implanted 6H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Dupeyrat, C., E-mail: cyril.dupeyrat@etu.univ-poitiers.f [Laboratoire de Physique des materiaux (PhyMat), SP2MI, teleport 2, Bvd M. et P. Curie, 86962 Chasseneuil-Futuroscope (France); Declemy, A.; Drouet, M.; Eyidi, D. [Laboratoire de Physique des materiaux (PhyMat), SP2MI, teleport 2, Bvd M. et P. Curie, 86962 Chasseneuil-Futuroscope (France); Thome, L.; Debelle, A. [Centre de Spectrometrie Nucleaire et Spectrometrie de Masse (CSNSM), Universite Paris-Sud, Bat 104, 91405 Orsay (France); Viret, M. [Service de Physique de l' Etat Condense (CAPMAG/SPEC), Centre d' Etudes de Saclay, 91191 Gif sur Yvette (France); Ott, F. [Laboratoire Leon Brillouin (CAPMAG/LLB), Centre d' Etudes de Saclay, 91191 Gif sur Yvette (France)

    2009-12-15

    Single crystalline 6H-SiC near (0 0 0 1)-oriented p-type samples were co-implanted at 550 deg. C with Fe ions at different energies and fluences ranging from 30 to 160 keV and from 2x10{sup 15} to 8x10{sup 15} ions cm{sup -2} with the aim to get so-called diluted magnetic semiconductors (DMS). Different treatments for implantation-induced damage recovery and iron incorporation and activation in the SiC matrix have been studied: the effects of rapid thermal annealing (RTA) on microstructure and magnetic properties of Fe-implanted 6H-SiC are compared to those of laser processing in the solid phase.

  9. Clinical and histological healing pattern of peri-implantitis lesions following non-surgical treatment with an Er:YAG laser.

    NARCIS (Netherlands)

    Schwarz, F.; Bieling, K.; Nuesry, E.; Sculean, A.; Becker, J.M.

    2006-01-01

    BACKGROUND AND OBJECTIVES: The aim of the present study was to assess clinical and histo-pathological healing pattern of peri-implantitis lesions following non-surgical treatment with an Er:YAG laser (ERL). STUDY DESIGN/MATERIALS AND METHODS: Twelve patients suffering from peri-implantitis (n = 12

  10. Characteristics of BF2, Ga and In implanted Si after FLA and RTA annealing

    Science.gov (United States)

    Wo, Bo; Matsunaga, Yusuke; Aid, Siti Rahmah Binti; Matsumoto, Satoru; Borland, John; Tanjyo, Masayasu

    2012-11-01

    The dopant diffusion, electrical activation, diode I-V characteristics and damage recovery of BF2, Ga and In implanted Si after annealing have been investigated for samples with the peak concentration of 1.0×1019 cm×3 as p-type dopant atoms. Within this concentration, Ga implanted samples have the lowest sheet resistance and lowest leakage current in diode I-V with good crystalline recovery.

  11. Modification effects in ion-implanted SiO[sub 2] spin-on-glass

    Energy Technology Data Exchange (ETDEWEB)

    Moriya, N.; Kalish, R. (Israel Inst. of Technology, Haifa (Israel)); Shacham-Diamond, Y. (Cornell Univ., Ithaca, NY (United States))

    1993-05-01

    The effects of ion-implantation on both polysiloxane and silicate spin-on-glass thin films were studied and are reported here. The authors have shown, using various analysis techniques, that the damage induced by the implantation drastically modified the film properties. A pronounced volume shrinkage was observed in polysiloxane films after the implantation and a respective increase in the effective refractive index of the oxide layer was measured. An infrared transmission study of the samples suggests that the ion-implanted samples have fewer carbon-based components and less hydrogen than the unimplanted samples. Similar measurements using silicate-type spin-on-glass films have shown only a slight variation of the thickness, the refractive index, and the infrared transmission spectrum. Both material types change their etching characteristics in wet reagents after ion-implantation. The etch rate in HF solutions of the spin-on SiO[sub 2] materials was lowered after the implant, and occasionally an inhibition period before any etching could be observed. Metal-isolator-silicon (MIS) capacitors with spin-on oxide additionally were tested before and after the implantation and the results are reported and discussed here. Stress characterization indicates that a lower overall internal stress exists in the ion-implanted films compared to the as-deposited layers. Based on the results presented, the authors conclude that the ion-implantation densifies the spin-on SiO[sub 2] film and reduces the carbon content in the layer. They suggest that these material modifications are related to the radiation damage induced by the implantation and to a reordering state of the atomic structure during the implantation process.

  12. Pulsed laser annealing of high-dose Ag+-ion implanted Si layer

    Science.gov (United States)

    Batalov, R. I.; Nuzhdin, V. I.; Valeev, V. F.; Vorobev, V. V.; Osin, Yu N.; Ivlev, G. D.; Stepanov, A. L.

    2018-01-01

    The formation of a crystalline composite Ag:Si material with Ag nanoparticles by low-energy (E  =  30 keV) high-dose (D  =  1.5  ×  1017 ion cm‑2) Ag+ implantation into a monocrystalline c-Si substrate followed by nanosecond pulsed laser annealing (PLA) is demonstrated. Compared to traditional thermal annealing, PLA allows us to perform local heating of the sample both for its depth and area, and eliminate implantation-induced defects more efficiently, due to rapid liquid-phase recrystallization. Moreover, dopant diffusion during a nanosecond laser pulse is mainly limited by the molten region, where the dopant diffusion coefficient is several orders of magnitude higher than in the solid state. During PLA by a ruby laser (λ  =  0.694 µm), the optical probing of the irradiated zone at λ  =  1.064 µm with registration of time-dependent reflectivity R(t) was carried out. By scanning electron microscopy, it was established that Ag+ implantation leads to the creation of a thin amorphous Ag:Si layer of porous structure, containing Ag nanoparticles with sizes of 10–30 nm. PLA with energy density W  =  1.2–1.8 J cm‑2 results in the melting of the implanted layer (d ~ 60 nm) and the topmost layers of the c-Si substrate (d  x-ray (EDX) spectroscopy did not show a noticeable change of Ag atomic concentration in the implanted layer after PLA. Spectral dependence R(λ) of Ag:Si layers showed the partial recovery of c-Si bands with maxima at 275 and 365 nm with simultaneous weakening of plasmon band for Ag nanoparticles in Si at 835 nm.

  13. The annealing behavior of hydrogen implanted into Al-Si alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ogura, Masahiko; Yamaji, Norisuke; Imai, Makoto; Itoh, Akio; Imanishi, Nobutsugu [Kyoto Univ. (Japan). Faculty of Engineering

    1997-03-01

    We have studied effects of not only defects but also an added elements on trap-sites of hydrogen in metals. For the purpose, we observed depth profiles and thermal behaviors of hydrogen implanted into Al-1.5at.%Si alloy samples in an implantation-temperature range of liquid nitrogen temperature (LNT) to 373K at different doses. The results were compared with those for pure aluminum samples. It was found that hydrogen is trapped as molecules in grain boundaries of Al/Si. (author)

  14. Boron diffusion in Ge{sup +} premorphized and BF{sub 2} implanted Si(001)

    Energy Technology Data Exchange (ETDEWEB)

    Zou, L.F.; Acosta-Ortiz, S.E. [Centro de Investigaciones en Optica, A.C. Unidad Aguascalientes, Juan de Montoro No. 207, Zona Centro, 20000 Aguascalientes (Mexico); Zou, L.X. [Computer Science Department, Zhongnan University for Nationalities Wuhan, Hubei 430074 (China); Regalado, L.E. [Centro de Investigaciones en Optica, Loma del Bosque No. 115, Loma del Campestre, 37000 Leon, Gunajuato (Mexico); Sun, D.Z.; Wang, Z.G. [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, (China)

    1998-12-31

    The annealing behavior of Si implanted with Ge and then BF{sub 2} has been characterized by double crystal X-ray diffraction (DCXRD) and secondary ion mass spectroscopy (SIMS). The results show that annealing at 600 Centigrade for 60 minutes can only remove a little damage induced by implantation and nearly no redistribution of Ge and B atoms has occurred during the annealing. The initial crystallinity of Si is fully recovered after annealing at 950 Centigrade for 60 minutes and accompanied by Ge diffusion. Very shallow boron junction depth has been formed. When annealing temperature rises to 1050 Centigrade, B diffusion enhances, which leads to a deep diffusion and good distribution of B atoms into the Si substrate. The X-ray diffraction (004) rocking curves from the samples annealed at 1050 Centigrade for 60 minutes display two Si Ge peaks, which may be related to the B concentration profiles. (Author)

  15. RBS/Channeling study of Er doped GaN films grown by MBE on Si(1 1 1) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, K.; Vianden, R.; Birkhahn, R.; Steckl, A.J.; Silva, M.F. da; Soares, J.C.; Alves, E. E-mail: ealves@itn1.itn.pt

    2000-03-01

    The influence of the Ga cell temperature on the quality of GaN films grown by MBE on p-Si(1 1 1) substrates was studied for cell temperatures (T{sub Ga}) in the range from 865 deg. C to 922 deg. C using the RBS/Channeling technique. The films were in situ doped during growth with Er at a constant cell temperature. The films show a strong dependence of the crystalline quality on the Ga cell temperature with the best films grown at T{sub Ga}=915 deg C. For temperatures T{sub Ga} below 880 deg. C the films showed no channeling effect. The thickness increases linearly with the temperature suggesting that changes in the Ga flux influence the growth process. The decrease of the Ga flux allows the incorporation of higher Er concentrations in the films. The data showed that a maximum value of about 0.35 at% was reached under the chosen growth conditions. The Er ions occupy mainly the Ga sublattice in the films with single crystalline quality. A comparison of the angular scans through the <0 0 0 1> and the <1 0 1 =macron 1> axes with Monte Carlo simulations leads to the conclusion that a majority ({approx}90%) of the Er ions occupies Ga sites.

  16. Carbon nanotube growth from catalytic nano-clusters formed by hot-ion-implantation into the SiO{sub 2}/Si interface

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, Yasushi, E-mail: yhoshino@kanagawa-u.ac.jp [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); Arima, Hiroki; Yokoyama, Ai; Saito, Yasunao; Nakata, Jyoji [Department of Information Sciences, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan)

    2012-07-01

    We have studied growth of chirality-controlled carbon nanotubes (CNTs) from hot-implantation-formed catalytic nano-clusters in a thermally grown SiO{sub 2}/Si substrate. This procedure has the advantage of high controllability of the diameter and the number of clusters by optimizing the conditions of the ion implantation. In the present study, Co{sup +} ions with ion dose of 8 Multiplication-Sign 10{sup 16} cm{sup -2} are implanted in the vicinity of the SiO{sub 2}/Si interface at 300 Degree-Sign C temperature. The implanted Co atoms located in the SiO{sub 2} layer has an amorphous-like structure with a cluster diameter of several nm. In contrast, implanted Co atoms in the Si substrate are found to take a cobalt silicide structure, confirmed by the high-resolution image of transmission electron microscope. CNTs are grown by microwave-plasma-enhanced chemical vapor deposition. We have confirmed a large amount of vertically-aligned multi-walled CNTs from the Co nano-clusters formed by the hot-ion-implantation near the SiO{sub 2}/Si interface.

  17. Field-induced non-collinear magnetic structures in Er sub 2 Fe sub 14 B-based compounds. [Er sub 2 (Fe sub 1-x Ga sub x ) sub 14 B; Er sub 2 (Fe sub 1-x Si sub x ) sub 14 B; Er sub 2 (Fe sub 1-x Co sub x ) sub 14 B

    Energy Technology Data Exchange (ETDEWEB)

    Radwanski, R.J.; Boer, F.R. de (Van der Waals-Zeeman Lab., Univ. van Amsterdam (Netherlands)); Zhong, X.P. (Van der Waals-Zeeman Lab., Univ. van Amsterdam (Netherlands) Magnetism Lab., Inst. of Physics, Academia Sinica, Beijing (China)); Yang, F.M.; Li, J.Y. (Magnetism Lab., Inst. of Physics, Academia Sinica, Beijing (China)); Kohashi, T.; Ono, M.; Date, M. (Dept. of Physics, Osaka Univ. (Japan)); Yamagishi, A. (Research Center for Extreme Materials, Osaka Univ. (Japan))

    1992-02-01

    Magnetic isotherms have been measured at 4.2 K on magnetically aligned polycrystalline Er{sub 2}(Fe,X){sub 14}B compounds with X=Ga, Si or Co. A field-induced transition of the First-Order Moment-Reorientation (FOMR) type with the formation of a non-collinear magnetic structure of the 3d and 4f sublattices has been observed. The transition-field value, 42 T for Er{sub 2}Fe{sub 14}B, decreases significantly with increasing concentration of the substitutions. An exchange field of 219 T for Er{sub 2}Fe{sub 14}B has been derived. (orig.).

  18. Boron gettering on cavities induced by helium implantation in Si

    Science.gov (United States)

    Roqueta, F.; Alquier, D.; Ventura, L.; Dubois, Ch.; Jérisian, R.

    2001-10-01

    In this paper, we shed light on the strong interaction between the cavity layer induced by helium implantation and boron. First of all, we evidence the impact of He gettering step on a boron-diffused profile. In order to study the boron-cavity interaction, we had used uniformly boron-doped wafers implanted with helium at high dose and anneal using usual furnace annealing (FA) as well as rapid thermal annealing. Then, to avoid any precipitation phenomena, conditions were chosen to not exceed the boron solid solubility value. Our experimental results exhibit a large trapping of boron within the cavity layer. This trapping occurs since the early stage of the annealing. These results enable us to have better understanding of this He gettering step as well as its interaction with boron atoms, which are of great interest for device.

  19. Advances in bone surgery: the Er:YAG laser in oral surgery and implant dentistry

    National Research Council Canada - National Science Library

    Stübinger

    2010-01-01

    ...;rich, SwitzerlandAbstract: The erbium-doped yttrium aluminium garnet (Er:YAG) laser has emerged as a possible alternative to conventional methods of bone ablation because of its wavelength of 2.94 &mu...

  20. Photoluminescence behavior of silicon nanocrystals produced by hot implantation in SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sias, U.S. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 Porto Alegre-RS (Brazil) and Centro Federal de Educacao Tecnologica (CEFET-RS), 96015-360 Pelotas-RS (Brazil)]. E-mail: uilson@if.ufrgs.br; Amaral, L. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 Porto Alegre-RS (Brazil); Behar, M. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 Porto Alegre-RS (Brazil); Boudinov, H. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-970 Porto Alegre-RS (Brazil); Moreira, E.C. [Centro Universitario Franciscano (UNIFRA), 97010-032, Santa Maria-RS (Brazil)

    2006-01-15

    In this work we present a photoluminescence (PL) study on Si nanocrystals produced by ion implantation on SiO{sub 2} targets at temperatures ranging between 25 and 800 deg.C and subsequently annealed in N{sub 2} atmosphere. The PL measurements were performed at low excitation power (20 mW/cm{sup 2}) in order to avoid nonlinear effects. Broad PL spectra were obtained (from 650 up to 1050 nm), presenting a line shape structure that can be reproduced by two superimposed peaks at around 780 and 950 nm. We have observed that both PL intensity and line shape change by varying the annealing as well as the implantation temperatures. Implantations performed at 400 deg.C or higher produce a remarkable effect in the PL line shape, evidenced by a strong redshift, and a striking intensity increase of the peak located at the long wavelength side of the PL spectrum.

  1. Novel Si ion implantation technique for improving the radiation hardness of SOI pseudo-MOS transistor

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanwei [Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan, Hunan 411105 (China); State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Huang, Huixiang; Bi, Dawei [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Tang, Minghua, E-mail: mhtang@xtu.edu.cn [Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan, Hunan 411105 (China); Zhang, Zhengxuan [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2014-01-15

    The pseudo-MOS transistor is a quick and effective technique for characterizing the electrical properties of silicon-on-insulator (SOI) wafer. We investigated the total ionizing dose (TID) response of pseudo-MOS transistors fabricated on SOI wafers hardened by single or multiple step Si ion implantation. It is demonstrated that the two Si ion implantation methods can both improve the radiation hardness of SOI wafers owing to the generation of deep electron traps in the buried oxide (BOX). However, the lattice damage of top silicon film caused by the single step implantation compared with the multiple degenerates the electrical properties of transistors, especially for the sub-threshold swing. The high resolution transmission electron microscopy (HRTEM) was used to observe the lattice quality.

  2. Suppression effect of silicon (Si on Er3+ 1.54μm excitation in ZnO thin films

    Directory of Open Access Journals (Sweden)

    Bo Xu

    2016-08-01

    Full Text Available We have investigated the photoluminescence (PL characteristics of ZnO:Er thin films on Si (100 single crystal and SiO2-on-silicon (SiO2 substrates, synthesized by radio frequency magnetron sputtering. Rutherford backscattering/channeling spectrometry (RBS, X-ray diffraction (XRD and atomic force microscope (AFM were used to analyze the properties of thin films. The diffusion depth profiles of Si were determined by second ion mass spectrometry (SIMS. Infrared spectra were obtained from the spectrometer and related instruments. Compared with the results at room temperature (RT, PL (1.54μm intensity increased when samples were annealed at 250°C and decreased when at 550°C. A new peak at 1.15μm from silicon (Si appeared in 550°C samples. The Si dopants in ZnO film, either through the diffusion of Si from the substrate or ambient, directly absorbed the energy of pumping light and resulted in the suppression of Er3+ 1.54μm excitation. Furthermore, the energy transmission efficiency between Si and Er3+ was very low when compared with silicon nanocrystal (Si-NC. Both made the PL (1.54μm intensity decrease. All the data in experiments proved the negative effects of Si dopants on PL at 1.54μm. And further research is going on.

  3. Anti-infective therapy with an Er:YAG laser: influence on peri-implant healing.

    NARCIS (Netherlands)

    Sculean, A.; Schwarz, F.; Becker, J.M.

    2005-01-01

    In addition to conventional treatment modalities (mechanical and chemical), the use of lasers has been increasingly proposed for the treatment of periodontal and peri-implant infections (i.e., cleaning and detoxification of implant surfaces). Preliminary results from basic studies have pointed to

  4. Electrical activation of nitrogen heavily implanted 3C-SiC(1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fan, E-mail: f.li.1@warwick.ac.uk [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Sharma, Yogesh; Shah, Vishal; Jennings, Mike [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Pérez-Tomás, Amador [ICN2 – Institut Catala de Nanociència i Nanotecnologia, Campus UAB, 08193 Bellaterra, Barcelona (Spain); Myronov, Maksym [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Fisher, Craig [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom); Leadley, David [Physics Department, University of Warwick, Coventry CV4 7AL (United Kingdom); Mawby, Phil [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2015-10-30

    Highlights: • Nitrogen is fully activated by 1175 °C annealing for 1.5 × 10{sup 19} cm{sup −3} doped 3C-SiC. • Free donor concentration is found to readily saturate in 3C-SiC at ∼7 × 10{sup 19} cm{sup −3}. • 3C-SiC is found to have complete donor thermal ionization above 150 K. • Donor in 1.5 × 10{sup 19} cm{sup −3} nitrogen implanted 3C-SiC has an energy level ∼15 meV. • The SiO{sub 2} cap is found to have a bigger influence on low and medium doped samples. - Abstract: A degenerated wide bandgap semiconductor is a rare system. In general, implant levels lie deeper in the band-gap and carrier freeze-out usually takes place at room temperature. Nevertheless, we have observed that heavily doped n-type degenerated 3C-SiC films are achieved by nitrogen implantation level of ∼6 × 10{sup 20} cm{sup −3} at 20 K. According to temperature dependent Hall measurements, nitrogen activation rates decrease with the doping level from almost 100% (1.5 × 10{sup 19} cm{sup −3}, donor level 15 meV) to ∼12% for 6 × 10{sup 20} cm{sup −3}. Free donors are found to saturate in 3C-SiC at ∼7 × 10{sup 19} cm{sup −3}. The implanted film electrical performances are characterized as a function of the dopant doses and post implantation annealing (PIA) conditions by fabricating Van der Pauw structures. A deposited SiO{sub 2} layer was used as the surface capping layer during the PIA process to study its effect on the resultant film properties. From the device design point of view, the lowest sheet resistivity (∼1.4 mΩ cm) has been observed for medium doped (4 × 10{sup 19} cm{sup −3}) sample with PIA 1375 °C 2 h without a SiO{sub 2} cap.

  5. Structural factors impacting carrier transport and electroluminescence from Si nanocluster-sensitized Er ions.

    Science.gov (United States)

    Cueff, Sébastien; Labbé, Christophe; Jambois, Olivier; Berencén, Yonder; Kenyon, Anthony J; Garrido, Blas; Rizk, Richard

    2012-09-24

    We present an analysis of factors influencing carrier transport and electroluminescence (EL) at 1.5 µm from erbium-doped silicon-rich silica (SiOx) layers. The effects of both the active layer thickness and the Si-excess content on the electrical excitation of erbium are studied. We demonstrate that when the thickness is decreased from a few hundred to tens of nanometers the conductivity is greatly enhanced. Carrier transport is well described in all cases by a Poole-Frenkel mechanism, while the thickness-dependent current density suggests an evolution of both density and distribution of trapping states induced by Si nanoinclusions. We ascribe this observation to stress-induced effects prevailing in thin films, which inhibit the agglomeration of Si atoms, resulting in a high density of sub-nm Si inclusions that induce traps much shallower than those generated by Si nanoclusters (Si-ncs) formed in thicker films. There is no direct correlation between high conductivity and optimized EL intensity at 1.5 µm. Our results suggest that the main excitation mechanism governing the EL signal is impact excitation, which gradually becomes more efficient as film thickness increases, thanks to the increased segregation of Si-ncs, which in turn allows more efficient injection of hot electrons into the oxide matrix. Optimization of the EL signal is thus found to be a compromise between conductivity and both number and degree of segregation of Si-ncs, all of which are governed by a combination of excess Si content and sample thickness. This material study has strong implications for many electrically-driven devices using Si-ncs or Si-excess mediated EL.

  6. Modeling of implantation and mixing damage during etching of SiO{sub 2} over Si in fluorocarbon plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Wang Mingmei; Kushner, Mark J. [Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50010 (United States); Department of Electrical Engineering and Computer Science, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States)

    2011-09-15

    Energetic ion bombardment during plasma etching of microelectronics devices is necessary to activate chemical process and define features through the ions' anisotropic trajectories. These energetic fluxes can also cause damage and mixing of the constituents of crystalline lattices. These properties are likely best modeled using molecular dynamics (MD) simulations. The computational expense of these techniques makes feature scale simulations difficult, and so motivates development of approximate methods that can be used to model full features. In this regard, an implantation and mixing model has been developed and implemented into a Monte Carlo feature profile model to simulate the mixing and damage to the underlying Si during high aspect ratio (HAR) etching of SiO{sub 2} trenches. Fluxes to the surface were provided by a reactor scale model. The feature scale model was validated by comparison to the mixing produced by Ar{sup +} bombardment of Si with and without F and CF fluxes as predicted by MD simulations. Scaling of mixing damage of underlying Si during HAR of SiO{sub 2} etching in Ar/C{sub 4}F{sub 8}/O{sub 2} plasmas for rf bias powers of 1-4 kW was investigated. The authors found that mixing damage at the bottom of HAR features, though increasing in magnitude with increasing ion energy, does not scale as dramatically as on flat surfaces. This is due to the reflection of ions off of sidewalls which moderate the ion energies.

  7. Chinese Herbal Formulas Si-Wu-Tang and Er-Miao-San Synergistically Ameliorated Hyperuricemia and Renal Impairment in Rats Induced by Adenine and Potassium Oxonate

    Directory of Open Access Journals (Sweden)

    Yongping Guo

    2015-10-01

    Full Text Available Background/Aims: Hyperuricemia is an independent risk factor for chronic kidney disease and cardiovascular disease. Here, we examined the combined protective effects of Chinese herbal formula Si-Wu-Tang and Er-Miao-San on hyperuricemia and renal impairment in rats. Methods: Rats were randomly divided into normal rats, hyperuricemic rats, and hyperuricemic rats orally administrated with benzbromarone (4.5 mg·kg-1·d-1, Si-Wu-Tang (3.78 g·kg-1·d-1 and Si-Wu-Tang plus Er-Miao-San (6.48 g·kg-1·d-1 for 4 weeks. Hyperuricemic rats were orally gavaged with adenine (0.1 g·kg-1·d-1 and potassium oxonate (1.5 g·kg-1·d-1 daily for 4 weeks. Serum uric acid, creatinine, total cholesterol (TCH, triglyceride and blood urea nitrogen (BUN concentrations, as well as urinary uric acid and microalbuminuria were measured weekly. Serum xanthine oxidase (XOD activity and renal histopathology were also evaluated. The renal expression of organic anion transporter 1 (OAT1 and organic anion transporter 3 (OAT3 was detected by western blot. Results: Si-Wu-Tang plus Er-Miao-San lowered serum uric acid, creatinine, triglyceride and BUN levels to a greater degree than did Si-Wu-Tang alone. Si-Wu-Tang plus Er-Miao-San ameliorated microalbuminuria and renal histopathology, as well as decreased serum TCH concentration and XOD activity in hyperuricemic rats. Combination of Si-Wu-Tang and Er-Miao-San also led to a greater increase in OAT1 and OAT3 expression than did Siwutang alone. Conclusion: Si-Wu-Tang and Er-Miao-San synergistically ameliorated hyperuricemia and renal impairment in rats through upregulation of OAT1 and OAT3.

  8. Tuning the Er{sup 3+} sensitization by Si nanoparticles in nanostructured as-grown Al{sub 2}O{sub 3} films.

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Sanchez, S.; Serna, R.; Garcia Lopez, J.; Petrord-Long, A. K.; Tanase, M.; Kabius, B.; Materials Science Division; Inst. de Optica; Centro Nacionale de Aceleradores

    2009-01-01

    Nanostructured films consisting of single Si nanoparticles (NPs) and Er{sup 3+} ions layers separated by nanometer-scale Al{sub 2}O{sub 3} layers of controlled thickness have been prepared in order to tune the energy transfer between Si NPs and Er{sup 3+} ions. The amorphous Si NPs with an effective diameter of {approx}4.5 nm are formed during growth and are able to sensitize the Er{sup 3+} ions efficiently with no postannealing treatments. The characteristic distance for energy transfer from Si NPs to Er{sup 3+} ions in Al{sub 2}O{sub 3} is found to be in the 1 nm range. It is shown that in the nanostructured films, it is possible to achieve an optimized configuration in which almost all the Er{sup 3+} ions have the potential to be excited by the Si NPs. This result stresses the importance of controlling the dopant distribution at the nanoscale to achieve improved device performance.

  9. Neutron scattering study on R{sub 2}PdSi{sub 3} (R=Ho,Er,Tm) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Fei

    2010-12-14

    Previous studies on the family of inter-metallic rare-earth compounds R{sub 2}PdSi{sub 3} revealed multifaceted magnetic properties, for instance, spin-glass like behavior. Experimental observations include: Signs of a crystallographic superstructure, complicated magnetic structures both in zero field and in applied magnetic fields as well as a generic phase in applied fields for compounds in the series with the heavy rare-earths R=Gd, Tb, Dy, Ho, Er and Tm. This thesis expands the studies on the magnetic properties of R{sub 2}PdSi{sub 3} employing mainly neutron scattering on single crystals with the focus on the compounds with R=Ho, Er and Tm. A detailed analysis of the crystallographic superstructure using modulation wave approach and group theory is presented. The resulting structure implies the existence of two different rare-earth sites with reduced symmetry and an arrangement of the different sites according to sequences as determined by the superstructure. It is shown that the reduced symmetry of the rare-earth sites is explicitly observed in the energy spectra of inelastic neutron scattering. The results on the magnetic structures and excitations are shown and discussed in the framework of the superstructure model. Specifically the generic phase in applied fields is interpreted as a direct consequence of the crystallographic superstructure. It is rather unusual that a crystallographic superstructure is playing such a decisive, and through the field dependence also tunable role in determining the magnetic properties as observed in R{sub 2}PdSi{sub 3}. The mediating interactions between the crystallographic part and the magnetic part of the system are discussed. (orig.)

  10. Si-nanocrystal-based LEDs fabricated by ion implantation and plasma-enhanced chemical vapour deposition

    Science.gov (United States)

    Perálvarez, M.; Barreto, J.; Carreras, Josep; Morales, A.; Navarro-Urrios, D.; Lebour, Y.; Domínguez, C.; Garrido, B.

    2009-10-01

    An in-depth study of the physical and electrical properties of Si-nanocrystal-based MOSLEDs is presented. The active layers were fabricated with different concentrations of Si by both ion implantation and plasma-enhanced chemical vapour deposition. Devices fabricated by ion implantation exhibit a combination of direct current and field-effect luminescence under a bipolar pulsed excitation. The onset of the emission decreases with the Si excess from 6 to 3 V. The direct current emission is attributed to impact ionization and is associated with the reasonably high current levels observed in current-voltage measurements. This behaviour is in good agreement with transmission electron microscopy images that revealed a continuous and uniform Si nanocrystal distribution. The emission power efficiency is relatively low, ~10-3%, and the emission intensity exhibits fast degradation rates, as revealed from accelerated ageing experiments. Devices fabricated by chemical deposition only exhibit field-effect luminescence, whose onset decreases with the Si excess from 20 to 6 V. The absence of the continuous emission is explained by the observation of a 5 nm region free of nanocrystals, which strongly reduces the direct current through the gate. The main benefit of having this nanocrystal-free region is that tunnelling current flow assisted by nanocrystals is blocked by the SiO2 stack so that power consumption is strongly reduced, which in return increases the device power efficiency up to 0.1%. In addition, the accelerated ageing studies reveal a 50% degradation rate reduction as compared to implanted structures.

  11. Si-nanocrystal-based LEDs fabricated by ion implantation and plasma-enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Peralvarez, M; Carreras, Josep; Navarro-Urrios, D; Lebour, Y; Garrido, B [MIND, IN2UB, Department of Electronics, University of Barcelona, C/Marti i Franques 1, PL2, E-08028 Barcelona (Spain); Barreto, J; DomInguez, C [IMB-CNM, CSIC, Bellaterra, E-08193 Barcelona (Spain); Morales, A, E-mail: mperalvarez@el.ub.e [INAOE, Electronics Department, Apartado 51, Puebla 72000 (Mexico)

    2009-10-07

    An in-depth study of the physical and electrical properties of Si-nanocrystal-based MOSLEDs is presented. The active layers were fabricated with different concentrations of Si by both ion implantation and plasma-enhanced chemical vapour deposition. Devices fabricated by ion implantation exhibit a combination of direct current and field-effect luminescence under a bipolar pulsed excitation. The onset of the emission decreases with the Si excess from 6 to 3 V. The direct current emission is attributed to impact ionization and is associated with the reasonably high current levels observed in current-voltage measurements. This behaviour is in good agreement with transmission electron microscopy images that revealed a continuous and uniform Si nanocrystal distribution. The emission power efficiency is relatively low, {approx}10{sup -3}%, and the emission intensity exhibits fast degradation rates, as revealed from accelerated ageing experiments. Devices fabricated by chemical deposition only exhibit field-effect luminescence, whose onset decreases with the Si excess from 20 to 6 V. The absence of the continuous emission is explained by the observation of a 5 nm region free of nanocrystals, which strongly reduces the direct current through the gate. The main benefit of having this nanocrystal-free region is that tunnelling current flow assisted by nanocrystals is blocked by the SiO{sub 2} stack so that power consumption is strongly reduced, which in return increases the device power efficiency up to 0.1%. In addition, the accelerated ageing studies reveal a 50% degradation rate reduction as compared to implanted structures.

  12. Fabrication of a novel nanocomposite Ag/graphene@SiO2-NaLuF4:Yb,Gd,Er for large enhancement upconversion luminescence.

    Science.gov (United States)

    Yin, Dongguang; Cao, Xianzhang; Zhang, Lu; Tang, Jingxiu; Huang, Wenfeng; Han, Yanlin; Wu, Minghong

    2015-06-28

    Upconversion nanocrystals have a lot of advantages over other fluorescent materials. However, their applications are still limited due to their comparatively low upconversion luminescence (UCL). In the present study, a novel nanocomposite of Ag/graphene@SiO2-NaLuF4:Yb,Gd,Er for enhancing UCL was fabricated successfully, and its morphology, crystalline phase, composition, and fluorescent property were investigated. It is interesting to find that the Ag/graphene@SiO2-NaLuF4:Yb,Gd,Er and Ag@SiO2-NaLuF4:Yb,Gd,Er nanocomposites showed high UCL enhancements of 52- and 10-fold compared to the control of Ag-free nanocomposite SiO2-NaLuF4:Yb,Gd,Er, respectively. The enhancement of 52-fold is greater than those reported in our previous studies and some papers. Moreover, the measured life times of the Ag-presented nanocrystals were longer than that of Ag-absent counterparts. These enhancements of UCL can be ascribed to the effect of metal-enhanced fluorescence, which is caused by the enhancement of the local electric field. The UCL intensity of Ag/graphene@SiO2-NaLuF4:Yb,Gd,Er was 5.2-fold higher than that of Ag@SiO2-NaLuF4:Yb,Gd,Er, indicating that graphene presented in the fabricated nanocomposite structure favors metal-enhanced UCL. The small-sized Ag nanoparticles anchored on the graphene sheet mutually enhanced each other's polarizability and surface plasmon resonance, resulting in a big metal-enhanced UCL. This study provides a new strategy for effectively enhancing the UCL of upconversion nanocrystals. The enhancement potentially increases the overall upconversion nanocrystal detectability for highly sensitive biological, medical, and optical detections.

  13. Si+ ion implantation reduces the bacterial accumulation on the Ti6Al4V surface

    Science.gov (United States)

    Gallardo-Moreno, A. M.; Pacha-Olivenza, M. A.; Perera-Núñez, J.; González-Carrasco, J. L.; González-Martín, M. L.

    2010-11-01

    Ti6Al4V is one of the most commonly used biomaterials in orthopedic applications due to its interesting mechanical properties and reasonable biocompatibility. Nevertheless, after the implantation, microbial adhesion to its surface can provoke severe health problems associated to the development of biofilms and subsequent infectious processes. This work shows a modification of the Ti6Al4V surface by Si+ ion implantation which reduces the bacterial accumulation under shear forces. Results have shown that the number of bacteria remaining on the surface at the end of the adhesion experiments decreased for silicon-treated surface. In general, the new surface also behaved as less adhesive under in vitro flow conditions. Since no changes are observed in the electrical characteristics between the control and implanted samples, differences are likely related to small changes observed in hydrophobicity.

  14. Electronic band gap reduction and intense luminescence in Co and Mn ion-implanted SiO2

    Science.gov (United States)

    Green, R. J.; Zatsepin, D. A.; St. Onge, D. J.; Kurmaev, E. Z.; Gavrilov, N. V.; Zatsepin, A. F.; Moewes, A.

    2014-03-01

    Cobalt and manganese ions are implanted into SiO2 over a wide range of concentrations. For low concentrations, the Co atoms occupy interstitial locations, coordinated with oxygen, while metallic Co clusters form at higher implantation concentrations. For all concentrations studied here, Mn ions remain in interstitial locations and do not cluster. Using resonant x-ray emission spectroscopy and Anderson impurity model calculations, we determine the strength of the covalent interaction between the interstitial ions and the SiO2 valence band, finding it comparable to Mn and Co monoxides. Further, we find an increasing reduction in the SiO2 electronic band gap for increasing implantation concentration, due primarily to the introduction of Mn- and Co-derived conduction band states. We also observe a strong increase in a band of x-ray stimulated luminescence at 2.75 eV after implantation, attributed to oxygen deficient centers formed during implantation.

  15. Spatially Controlled Delivery of siRNAs to Stem Cells in Implants Generated by Multi-Component Additive Manufacturing

    DEFF Research Database (Denmark)

    Andersen, Morten Østergaard; Le, Dang Quang Svend; Chen, Muwan

    2013-01-01

    Additive manufacturing is a promising technique in tissue engineering, as it enables truly individualized implants to be made to fit a particular defect. As previously shown, a feasible strategy to produce complex multicellular tissues is to deposit different small interfering RNA (siRNA) in porous...... implants that are subsequently sutured together. In this study, an additive manufacturing strategy to deposit carbohydrate hydrogels containing different siRNAs is applied into an implant, in a spatially controlled manner. When the obtained structures are seeded with mesenchymal stem (stromal) cells......, the selected siRNAs are delivered to the cells and induces specific and localized gene silencing. Here, it is demonstrated how to replicate part of a patient's spinal cord from a computed tomography scan, using an additive manufacturing technique to produce an implant with compartmentalized siRNAs...

  16. Hyperfine interaction of Er3+ ions in Y2SiO5 : An electron paramagnetic resonance spectroscopy study

    Science.gov (United States)

    Guillot-Noël, O.; Goldner, Ph.; Du, Y. Le; Baldit, E.; Monnier, P.; Bencheikh, K.

    2006-12-01

    Electron paramagnetic resonance (EPR) spectroscopy of rare earth ions in crystals is a powerful tool to analyze the hyperfine structure of the rare earth ground state. This can be useful for coherent spectroscopy and quantum information applications where the hyperfine structure of the electronic levels is used. In this work, we give a detailed analysis of the hyperfine structure of the ground state [I15/24(0)] of Er3+ ions in Y2SiO5 . The electronic Zeeman, hyperfine, and quadrupole matrices are obtained from angular variations of the magnetic field in three orthogonal crystal planes. An excellent agreement is obtained between experimental and simulated magnetic field positions and relative intensities of EPR lines.

  17. Lattice location of implanted transition metals in 3C–SiC

    CERN Document Server

    AUTHOR|(CDS)2085259; Wahl, Ulrich; Martins Correia, Joao; David Bosne, Eric; Amorim, Lígia; Silva, Daniel; Castro Ribeiro Da Silva, Manuel; Bharuth-Ram, Krishanlal; Da Costa Pereira, Lino Miguel

    2017-01-01

    We have investigated the lattice location of implanted transition metal (TM) 56Mn, 59Fe and 65Ni ions in undoped single-crystalline cubic 3C–SiC by means of the emission channeling technique using radioactive isotopes produced at the CERN-ISOLDE facility. We find that in the room temperature as-implanted state, most Mn, Fe and Ni atoms occupy carbon-coordinated tetrahedral interstitial sites (TC). Smaller TM fractions were also found on Si substitutional (SSi) sites. The TM atoms partially disappear from ideal-TC positions during annealing at temperatures between 500 °C and 700 °C, which is accompanied by an increase in the TM fraction occupying both SSi sites and random sites. An explanation is given according to what is known about the annealing mechanisms of silicon vacancies in silicon carbide. The origin of the observed lattice sites and their changes with thermal annealing are discussed and compared to the case of Si, highlighting the feature that the interstitial migration of TMs in SiC is much slo...

  18. Implantation-Free 4H-SiC Bipolar Junction Transistors with Double Base Epi-layers

    Science.gov (United States)

    2007-05-14

    junction transistor ( BJT ) which is completely free of ion implantation and hence is free of the implantation- induced crystal damages and high-temperature...Index Terms—Silicon carbide, bipolar junction transistors ( BJTs ), power transistors ...Std Z39-18 I. INTRODUCTION 4H-SiC bipolar junction transistor ( BJT ) is an important switching device for high power and high temperature

  19. Phthalocyanine-Conjugated Upconversion NaYF4:Yb3+/Er3+@SiO2Nanospheres for NIR-Triggered Photodynamic Therapy in a Tumor Mouse Model.

    Science.gov (United States)

    Kostiv, Uliana; Patsula, Vitalii; Noculak, Agnieszka; Podhorodecki, Artur; Větvička, David; Poučková, Pavla; Sedláková, Zdenka; Horák, Daniel

    2017-12-19

    Photodynamic therapy (PDT) has garnered immense attention as a minimally invasive clinical treatment modality for malignant cancers. However, its low penetration depth and photodamage of living tissues by UV and visible light, which activate a photosensitizer, limit the application of PDT. In this study, monodisperse NaYF 4 :Yb 3+ /Er 3+ nanospheres 20 nm in diameter, that serve as near-infrared (NIR)-to-visible light converters and activators of a photosensitizer, were synthesized by high-temperature co-precipitation of lanthanide chlorides in a high-boiling organic solvent (octadec-1-ene). The nanoparticles were coated with a thin shell (≈3 nm) of homogenous silica via the hydrolysis and condensation of tetramethyl orthosilicate. The NaYF 4 :Yb 3+ /Er 3+ @SiO 2 particles were further functionalized by methacrylate-terminated groups via 3-(trimethoxysilyl)propyl methacrylate. To introduce a large number of reactive amino groups on the particle surface, methacrylate-terminated NaYF 4 :Yb 3+ /Er 3+ @SiO 2 nanospheres were modified with a branched polyethyleneimine (PEI) via Michael addition. Aluminum carboxyphthalocyanine (Al Pc-COOH) was then conjugated to NaYF 4 :Yb 3+ /Er 3+ @SiO 2 -PEI nanospheres via carbodiimide chemistry. The resulting NaYF 4 :Yb 3+ /Er 3+ @SiO 2 -PEI-Pc particles were finally modified with succinimidyl ester of poly(ethylene glycol) (PEG) in order to alleviate their future uptake by the reticuloendothelial system. Upon 980 nm irradiation, the intensive red emission of NaYF 4 :Yb 3+ /Er 3+ @SiO 2 -PEI-Pc-PEG nanoparticles completely vanished, indicating efficient energy transfer from the nanoparticles to Al Pc-COOH, which generates singlet oxygen ( 1 O 2 ). Last but not least, NaYF 4 :Yb 3+ /Er 3+ @SiO 2 -PEI-Pc-PEG nanospheres were intratumorally administered into mammary carcinoma MDA-MB-231 growing subcutaneously in athymic nude mice. Extensive necrosis developed at the tumor site of all mice 24-48 h after irradiation by laser at

  20. The role of nitrogen in luminescent Si nanoprecipitate formation during annealing of Si ion-implanted SiO sub 2 layers

    CERN Document Server

    Kachurin, G A; Zhuravlev, K S; Ruault, M O

    2001-01-01

    SiO sub 2 layers were implanted with 25 keV Si sup + and 13 keV N sup + ions with the doses of (1-4) x 10 sup 1 sup 6 cm sup - sup 2 and (0.2-2) x 10 sup 1 sup 6 cm sup - sup 2 , respectively. Then the samples were annealed at 900-1100 deg C to form luminescent silicon nanoprecipitates. The nitrogen effect on the process is controlled by photoluminescence spectra. It is found out that the photoluminescence intensity increases considerably at the appropriate ratio between silicon and nitrogen. It has been concluded that the interaction of nitrogen with excessive silicon results in increasing the number of precipitation centers. This raises the nanocrystals number and reduces their mean size

  1. Oxidation study of Sb + implanted Si(1 0 0) and Si(1 1 1) targets. Use of high-resolution RBS technique

    Science.gov (United States)

    Labbani, R.; Halimi, R.

    2004-03-01

    High-resolution Rutherford backscattering spectroscopy (RBS) was used to study the oxidation phenomenon of antimony-implanted silicon targets. The study was carried out with respect to antimony dose and silicon target orientation. The behavior of antimony ions before and after silicon oxidation was also investigated. Prior to the oxidation process, the Si(1 0 0) and Si(1 1 1) targets were implanted to 5×10 14 or 5×10 15 Sb +cm -2 dose, at 60 keV energy. The dry oxidation of the silicon specimens, was performed under oxygen atmosphere at 900°C for 30 min. The analysis was carried out by means of RBS technique in both random and channeling modes. A beam of H + particles was used for an energy of 0.3 MeV, with a detection resolution of 2 keV. It was shown that the oxidation phenomenon was more important on Si(1 1 1) targets than on Si(1 0 0). The SiO 2 oxide layer increased with the rise in antimony ions dose. Besides, after annealing under oxygen atmosphere, a good surface damage recovery was obtained for all implanted samples. An important quantity of antimony was found to be shadowed for the case of Si(1 0 0) targets which were implanted with 5×10 14 Sb +cm -2 dose. However, for the case of 5×10 15 Sb + cm -2 dose, no shadowing of antimony ions was observed.

  2. Preparation of Si sub 1 sub - sub x sub - sub y Ge sub x C sub y semiconductor films on Si by ion implantation and solid phase epitaxy

    CERN Document Server

    Liu Xue Qin; Zhen Cong Mian; Zhang Jing; Yang Yi; Guo Yong

    2002-01-01

    Si sub 1 sub - sub x sub - sub y Ge sub x C sub y ternary alloy semiconductor films were prepared on Si(100) substrates by C ion implanting SiGe films and subsequent solid phase epitaxy (SPE). Two-step annealing technique was employed in the SPE processing. The properties of the alloy films were determined using Rutherford backscattering spectroscopy (RBS), Fourier transform infrared spectroscopy (FTIR) and High-resolution x-ray diffraction (HRXRD) measurements. It is shown that C atoms are located at substitutional sites and the incorporation of C relieves the compressive strain in the SiGe layer

  3. Fe-implanted SiC as a potential DMS: X-ray diffraction and rutherford backscattering and channelling study

    Energy Technology Data Exchange (ETDEWEB)

    Dupeyrat, C., E-mail: cyril.dupeyrat@etu.univ-poitiers.f [Laboratoire de Physique des Materiaux (PhyMat), SP2MI, teleport 2, Bvd M. et P. Curie, 86962 Chasseneuil-Futuroscope (France); Declemy, A.; Drouet, M. [Laboratoire de Physique des Materiaux (PhyMat), SP2MI, teleport 2, Bvd M. et P. Curie, 86962 Chasseneuil-Futuroscope (France); Debelle, A.; Thome, L. [Centre de Spectrometrie Nucleaire et Spectrometrie de Masse (CSNSM), Universite Paris-Sud 11, Bat 104, 91405 Orsay (France)

    2010-10-01

    Single crystalline (0 0 0 1)-oriented 6H-SiC samples were implanted at 380 {sup o}C with low-energy Fe ions (in the 100 keV range) with the aim of synthesizing so-called diluted magnetic semiconductors. X-ray diffraction and Rutherford backscattering spectrometry and channeling are used to study the microstructural changes in these Fe-implanted SiC crystals submitted to furnace annealing and laser processing, both treatments being performed in order to eliminate the implantation-induced defects.

  4. Electronic structure of triple intermetallic compounds of RAl/sub 2/Si/sub 2/ type. [(R=Pr,Gd,Tb,Dy,Ho,Er,Tm,Yb,Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Nemoshkalenko, V.V.; Nagornyj, V.Ya.; Mamko, B.P.; Nikolyuk, P.K.; Gel, P.V.; Lutsiv, R.V.; Koterlin, M.D. (AN Ukrainskoj SSR, Kiev. Inst. Metallofiziki; L' vovskij Gosudarstvennyj Univ. (Ukrainian SSR))

    1981-11-01

    The electron structure of triple intermetallic compounds of RAl/sub 2/Si/sub 2/ type (R=Pr, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) is studied by X-ray spectral analysis. The study permits an assumption that the studied phases possess covalent bends besides metallic ones.

  5. Distribution of D1 dislocation luminescence centers in Si+-implanted silicon and the photoluminescence model

    Directory of Open Access Journals (Sweden)

    Sergeyi N. Nagornykh

    2015-06-01

    Full Text Available Using step-by-step removal of silicon layers, in which dislocation-related photoluminescence is observed after Si+ (100 keV, 1·1015 cm−2 ion implantation followed by high-temperature annealing in a chlorine containing atmosphere, it has been found that a majority of dislocation-related centers of luminescence at ~1.5 μm (D1 line is localized at the depths of Si+ ion ranges. Cross-sectional electron microscopy shows that the dislocations introduced by the implantation treatment (implantation plus annealing penetrate to depths of ~1 μm. A phenomenological model of the D1-line dislocation-related luminescence is developed based on the assumption that the K-centers and modified A-centers located in the atmospheres of dislocations are responsible for this luminescence line. The temperature dependence of luminescence intensity calculated on the basis of the model fits well the experimental data for the D1 line.

  6. Influence of n$^{+}$ and p$^{+}$ doping on the lattice sites of implanted Fe in Si

    CERN Document Server

    Silva, Daniel José; Correia, João Guilherme; Araújo, João Pedro

    2013-01-01

    We report on the lattice location of implanted $^{59}$Fe in n$^{+}$ and p$^{+}$ type Si by means of emission channeling. We found clear evidence that the preferred lattice location of Fe changes with the doping of the material. While in n$^{+}$ type Si Fe prefers displaced bond-centered (BC) sites for annealing temperatures up to 600°C, changing to ideal substitutional sites above 700°C, in p$^{+}$ type Si, Fe prefers to be in displaced tetrahedral interstitial positions after all annealing steps. The dominant lattice sites of Fe in n$^{+}$ type Si therefore seem to be well characterized for all annealing temperatures by the incorporation of Fe into vacancy-related complexes, either into single vacancies which leads to Fe on ideal substitutional sites, or multiple vacancies, which leads to its incorporation near BC sites. In contrast, in p$^{+}$ type Si, the major fraction of Fe is clearly interstitial (near-T or ideal T) for all annealing temperatures. The formation and possible lattice sites of Fe in FeB...

  7. Layer morphology and Al implant profiles after annealing of supersaturated, single-crystalline, amorphous, and nanocrystalline SiC

    Science.gov (United States)

    Heera, V.; Mücklich, A.; Dubois, C.; Voelskow, M.; Skorupa, W.

    2004-09-01

    Al supersaturated SiC layers (5×1020Alcm-3) were produced by multienergy, high-dose ion implantation into 6H- and 4H-SiC. Several implantation schemes with varying implantation sequence and temperature were investigated. In dependence on the implantation conditions damaged single-crystalline, amorphous, or nanocrystalline layers were formed. The layer morphology and Al distribution in the as-implanted state as well as structural changes and related Al redistribution after high-temperature annealing (1500-1700°C) were characterized by cross-sectional transmission electron microscopy, Rutherford backscattering spectrometry in combination with ion channeling, atomic force microscopy, and secondary-ion mass spectrometry. Remarkable Al redistribution effects have been found after annealing of Al supersaturated SiC. During high-temperature annealing Al atoms in excess to the solid solubility (2×1020Alcm-3) tend to precipitate in single-crystalline SiC whereas they diffuse out in amorphous or nanocrystalline SiC. Redistribution of Al with concentration below the solid solubility is governed by transient enhanced diffusion which can be controlled by the annealing scheme. Amorphization of SiC is advantageous in the case of Al doping to levels higher than the solid solubility because it prevents Al precipitation during annealing and helps to form boxlike Al profiles with smooth plateau and abrupt edge.

  8. Damage formation and recovery in Fe implanted 6H–SiC

    CERN Document Server

    Miranda, Pedro; Catarino, Norberto; Lorenz, Katharina; Correia, João Guilherme; Alves, Eduardo

    2012-01-01

    Silicon carbide doped with magnetic ions such as Fe, Mn, Ni or Co could make this wide band gap semiconductor part of the diluted magnetic semiconductor family. In this study, we report the implantation of 6H-SiC single crystals with magnetic $^{56}$Fe$^{+}$ ions with an energy of 150 keV. The samples were implanted with 5E14 Fe$^+$/cm$^{2}$ and 1E16 Fe$^+$/cm$^{2}$ at different temperatures to study the damage formation and lattice site location. The samples were subsequently annealed up to 1500°C in vacuum in order to remove the implantation damage. The effect of the annealing was followed by Rutherford Backscattering/Channeling (RBS/C) measurements. The results show that samples implanted above the critical amorphization temperature reveal a high fraction of Fe incorporated into regular sites along the [0001] axis. After the annealing at 1000°C, a maximum fraction of 75%, corresponding to a total of 3.8E14 Fe$^{+}$/cm$^{2}$, was measured in regular sites along the [0001] axis. A comparison is made betwee...

  9. Ferromagnetism in Mn-Implanted Epitaxially Grown Ge on Si(100)

    Energy Technology Data Exchange (ETDEWEB)

    Guchhait, S.; Jamil, M.; Ohldag, H.; Mehta, A.; Arenholz, E.; Lian, G.; Li Fatou, A.; Ferrer, D. A.; Markert, J. T.; Colombo, L.; Banerjee, S. K.

    2011-01-05

    We have studied ferromagnetism of Mn-implanted epitaxial Ge films on silicon. The Ge films were grown by ultrahigh vacuum chemical vapor deposition using a mixture of germane (GeH{sub 4}) and methylgermane (CH{sub 3}GeH{sub 3}) gases with a carbon concentration of less than 1 at. %, and observed surface rms roughness of 0.5 nm, as measured by atomic force microscopy. Manganese ions were implanted in epitaxial Ge films grown on Si (100) wafers to an effective concentration of 16, 12, 6, and 2 at. %. Superconducting quantum interference device measurements showed that only the three highest Mn concentration samples are ferromagnetic, while the fourth sample, with [Mn] = 2 at. %, is paramagnetic. X-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements indicate that localized Mn moments are ferromagnetically coupled below the Curie temperature. Isothermal annealing of Mn-implanted Ge films with [Mn] = 16 at. % at 300 C for up to 1200 s decreases the magnetization but does not change the Curie temperature, suggesting that the amount of the magnetic phase slowly decreases with time at this anneal temperature. Furthermore, transmission electron microscopy and synchrotron grazing incidence x-ray diffraction experiments show that the Mn-implanted region is amorphous, and we believe that it is this phase that is responsible for the ferromagnetism. This is supported by our observation that high-temperature annealing leads to recrystallization and transformation of the material into a paramagnetic phase.

  10. Hyperfine electric parameters calculation in Si samples implanted with {sup 57}Mn→{sup 57}Fe

    Energy Technology Data Exchange (ETDEWEB)

    Abreu, Y., E-mail: yabreu@ceaden.edu.cu [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Cruz, C.M.; Piñera, I.; Leyva, A.; Cabal, A.E. [Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Calle 30 No. 502 e/5ta y 7ma Ave., 11300 Miramar, Playa, La Habana (Cuba); Van Espen, P. [Departement Chemie, Universiteit Antwerpen, Middelheimcampus, G.V.130, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Van Remortel, N. [Departement Fysica, Universiteit Antwerpen, Middelheimcampus, G.U.236, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

    2014-07-15

    Nowadays the electronic structure calculations allow the study of complex systems determining the hyperfine parameters measured at a probe atom, including the presence of crystalline defects. The hyperfine electric parameters have been measured by Mössbauer spectroscopy in silicon materials implanted with {sup 57}Mn→{sup 57}Fe ions, observing four main contributions to the spectra. Nevertheless, some ambiguities still remain in the {sup 57}Fe Mössbauer spectra interpretation in this case, regarding the damage configurations and its evolution with annealing. In the present work several implantation environments are evaluated and the {sup 57}Fe hyperfine parameters are calculated. The observed correlation among the studied local environments and the experimental observations is presented, and a tentative microscopic description of the behavior and thermal evolution of the characteristic defects local environments of the probe atoms concerning the location of vacancies and interstitial Si in the neighborhood of {sup 57}Fe ions in substitutional and interstitial sites is proposed.

  11. COUP-TFII mediates progesterone regulation of uterine implantation by controlling ER activity.

    Directory of Open Access Journals (Sweden)

    Isao Kurihara

    2007-06-01

    Full Text Available Progesterone and estrogen are critical regulators of uterine receptivity. To facilitate uterine remodeling for embryo attachment, estrogen activity in the uterine epithelia is attenuated by progesterone; however, the molecular mechanism by which this occurs is poorly defined. COUP-TFII (chicken ovalbumin upstream promoter transcription factor II; also known as NR2F2, a member of the nuclear receptor superfamily, is highly expressed in the uterine stroma and its expression is regulated by the progesterone-Indian hedgehog-Patched signaling axis that emanates from the epithelium. To further assess COUP-TFII uterine function, a conditional COUP-TFII knockout mouse was generated. This mutant mouse is infertile due to implantation failure, in which both embryo attachment and uterine decidualization are impaired. Using this animal model, we have identified a novel genetic pathway in which BMP2 lies downstream of COUP-TFII. Epithelial progesterone-induced Indian hedgehog regulates stromal COUP-TFII, which in turn controls BMP2 to allow decidualization to manifest in vivo. Interestingly, enhanced epithelial estrogen activity, which impedes maturation of the receptive uterus, was clearly observed in the absence of stromal-derived COUP-TFII. This finding is consistent with the notion that progesterone exerts its control of implantation through uterine epithelial-stromal cross-talk and reveals that stromal-derived COUP-TFII is an essential mediator of this complex cross-communication pathway. This finding also provides a new signaling paradigm for steroid hormone regulation in female reproductive biology, with attendant implications for furthering our understanding of the molecular mechanisms that underlie dysregulation of hormonal signaling in such human reproductive disorders as endometriosis and endometrial cancer.

  12. Impurity/defect interactions during MeV Si{sup +} ion implantation annealing

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, A.; Koveshnikov, S.; Christensen, K. [North Carolina State Univ., Raleigh, NC (United States)] [and others

    1995-08-01

    Ion implantation of dopant atoms at MeV energies is currently being explored in several integrated circuit device manufacturing processes. MeV implantation offers immediate advantages such as vertical well modulation, latch-up protection, device structure isolation, and reduced temperature processing. Simultaneously, it presents an opportunity to achieve {open_quotes}proximity{close_quotes} gettering of impurities from the active device region by placing high impurity solubility and/or secondary defect gettering sites within microns of the surface. If the MeV implanted species is a dopant ion, all three gettering mechanisms, i.e, segregation, relaxation and injection, can be involved in the gettering process, complicating the analysis and optimization of the process. However, investigation of gettering using non-dopant Si{sup +} ion damage allows the relaxation component of the gettering process to be isolated and examined separately. In general, gettering is verified by a reduction in impurity concentration in the region of interest, usually the device region, and/or a build-up of concentration/precipitation in a non-device sink region. An alternate and more meaningful approach is to use simple devices as materials characterization probes via changes in the electrical activity of the gettering sites. Device space charge probes also allow the evolution of the defect sites upon contamination to be tracked. We report here results of the electrical, structural, and chemical characterization of MeV implanted Si{sup +} damage using Deep Level Transient Spectroscopy (DLTS), Transmission Electron Microscopy (TEM), and Secondary Ion Mass Spectroscopy (SIMS). The damage has been characterized both as a function of annealing from 600 to 1100{degrees}C for 1 hr, and after contamination with Fe followed by low temperature gettering annealing.

  13. Plasmonic properties of implanted Ag nanoparticles in SiO2 thin layer by spectroscopic ellipsometry

    Science.gov (United States)

    Battie, Yann; En Naciri, Aotmane; Chaoui, Nouari; Le Gall, Yann; Muller, Dominique; Carrada, Marzia; Mathiot, Daniel

    2017-08-01

    We report an uncommon study of the insertion of distributions of both volume fraction and depolarization factors in the modeling of the plasmonic properties of implanted Ag nanoparticles (Ag-NPs) in a SiO2 layer when using spectroscopic ellipsometry (SE) characterization. The Ag-NPs were embedded in the SiO2 matrix by Ag+ ion implantation at various doses of 0.5 × 1016, 1 × 1016, 2 × 1016, and 5 × 1016 ions cm-2. The formation of the Ag-NPs in a host matrix of SiO2 was controlled by transmission electron microscopy (TEM). The Ag-NPs are self-organized in the layer, and their mean radius ranges between 2 and 20 nm. The optical properties of layers were extracted by modeling the SE parameters by taking into account the depth profile concentration of Ag-NPs. The mixture of SiO2 and Ag-NP inclusions was modeled as an effective medium according to the shape distributed effective medium theory (SDEMT). In addition to the optical responses, it is shown that this model enables the explanation of the impact of NP shape distribution on the plasmon band and provides precious information about the NP shape characteristics. A good agreement was obtained between ellipsometry and TEM results. The distribution of the volume fraction in the film was found to lead to a gradient of effective dielectric function which was determined by the SDEMT model. The effective dielectric function reveals distinct Ag plasmon resonance varying as the Ag+ ions dose is varied. The real part of the dielectric function shows a significant variation around the plasmon resonance in accordance with the Kramers-Kronig equations. All determined optical parameters by SDEMT are provided and discussed. We highlight that SE combined with SDEMT calculations can be considered as a reliable tool for the determination of the NP shape and volume fraction distributions without the need of TEM.

  14. A pulse synthesis of beta-FeSi sub 2 layers on silicon implanted with Fe sup + ions

    CERN Document Server

    Batalov, R I; Terukov, E I; Kudoyarova, V K; Weiser, G; Kuehne, H

    2001-01-01

    The synthesis of thin beta-FeSi sub 2 films was performed by means of the Fe sup + ion implantation into Si (100) and the following nanosecond pulsed ion treatment of implanted layer. Using the beta-FeSi sub 2 beta-FeSi sub 2 e X-ray diffraction it is shown that the pulsed ion treatment results in the generation of the mixture of two phases: FeSi and beta-FeSi sub 2 with stressed crystal lattices. The following short-time annealing leads to the total transformation of the FeSi phase into the beta-FeSi sub 2 one. The Raman scattering data prove the generation of the beta-FeSi sub 2 at the high degree of the silicon crystallinity. The experimental results of the optical absorption testify to the formation of beta-FeSi sub 2 layers and precipitates with the straight-band structure. The photoluminescence signal at lambda approx = 1.56 mu m observes up to 210 K

  15. New Technique to Determine Gettering Efficiency of Heavy Metals and Its Application to Carbon-Ion-Implanted Si Epitaxial Wafers

    Science.gov (United States)

    Itoga, Toshihiko; Hozawa, Kazuyuki; Takeda, Kazuo; Isomae, Seiichi; Ohkura, Makoto

    2001-04-01

    Using a newly developed method to evaluate the gettering efficiency of Si wafers, we found that C-ion implantation prior to epitaxial growth greatly improves the gettering efficiency of heavy metals in epitaxial Si wafers. The gettering efficiency was evaluated through direct observation by total X-ray reflection fluorescence (TXRF) by counting the number of heavy metal atoms that diffused from the back to the front surface of wafers. Heavy metals were deposited on the backside surface of Si wafers from metal-dissolved aqua solution. Two-step annealing was carried out after the deposition. The first step caused metal diffusion and the second produced precipitation from the front surface of the wafers. The effectiveness of the method was confirmed by comparing the results obtained from as-received and intrinsic (or internal) gettering (IG)-processed Czochralski-grown Si wafers. The method was applied to C-ion-implanted epitaxial Si wafers to confirm the improvement in gettering efficiency in accordance with the implanted C dose. The effectiveness of the C-ion implantation was also confirmed by evaluating the electrical characteristics of the oxide grown on the Si wafers.

  16. High Power Self-Aligned, Trench-Implanted 4H-SiC JFETs

    Directory of Open Access Journals (Sweden)

    Vamvoukakis K.

    2017-01-01

    Full Text Available The process technology for the fabrication of 4H-SiC trenched-implanted-gate 4H–SiC vertical-channel JFET (TI-VJFET has been developed. The optimized TIVJFETs have been fabricated with self-aligned nickel silicide source and gate contacts using a process sequence that greatly reduces process complexity as it includes only four lithography steps. A source-pillars sidewall oxidation and subsequent removal of the metallization from the top of the sidewall oxide ensured isolation between gate and source. Optimum planarization of the source pillars top has been performed by cyclotene spin coating and etch back. The effect of the channel geometry on the electrical characteristics has been studied by varying its length (0.3 and 1.2μm and its width (1.5-5μm. The voltage blocking exhibits a triode shape, which is typical for a static-induction transistor (SIT operation. The transistors exhibited high ON current handling capabilities (Direct Current density >1kA/cm2 and values of RON ranging from 6 - 12 mΩ•cm2 depending on the channel length. Maximum voltage blocking was 800V limited by the edge termination. The maximum voltage gain was 51. Most transistors were normally-on. Normally-off operation has been observed for transistors lower than 2μm channel width (mask level and deep implantation.

  17. Martensitic Transformations and Mechanical and Corrosion Properties of Fe-Mn-Si Alloys for Biodegradable Medical Implants

    Science.gov (United States)

    Drevet, Richard; Zhukova, Yulia; Malikova, Polina; Dubinskiy, Sergey; Korotitskiy, Andrey; Pustov, Yury; Prokoshkin, Sergey

    2018-01-01

    The Fe-Mn-Si alloys are promising materials for biodegradable metallic implants for temporary healing process in the human body. In this study, three different compositions are considered (Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si, all in wt pct). The phase composition analysis by XRD reveals ɛ-martensite, α-martensite, and γ-austenite in various proportions depending on the manganese amount. The DSC study shows that the starting temperature of the martensitic transformation (M s) of the alloys decreases when the manganese content increases (416 K, 401 K, and 323 K (143 °C, 128 °C, and 50 °C) for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively). Moreover, mechanical compression tests indicate that these alloys have a much lower Young's modulus (E) than pure iron (220 GPa), i.e., 145, 133, and 118 GPa for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively. The corrosion behavior of the alloys is studied in Hank's solution at 310 K (37 °C) using electrochemical experiments and weight loss measurements. The corrosion kinetics of the Fe-Mn-Si increases with the manganese content (0.48, 0.59, and 0.80 mm/year for the Fe23Mn5Si, Fe26Mn5Si, and Fe30Mn5Si alloys, respectively). The alloy with the highest manganese content shows the most promising properties for biomedical applications as a biodegradable and biomechanically compatible implant material.

  18. Influence of P and As implantation of the formation of MoSi2

    Science.gov (United States)

    van Ommen, A. H.; Wolters, R. A. M.

    1985-12-01

    Molybdenum disilicide films have been formed by a reaction of Mo with polycrystalline silicon. Implantation of phosphorus or arsenic prior to reaction has been shown to have a large effect on the silicidation process. The object of implantation was to enhance the silicide reaction by creating damage at the metal-silicon interface. This, then, results in silicide films with less surface roughness (and a lower electrical resistivity). Molecular P+2 ions were found to be more effective in creating damage than single P+ ions, due to the fact that for P+2 ions two simultaneous collision cascades occur which overlap. Apart from the beneficial effect of implantation damage, the introduction of phosphorus has a deleterious effect on the properties of the silicide films. This phenomenon is explained by the presence of a thin and nonuniform native oxide layer which hinders the silicide reaction. Without addition of phosphorus, new nuclei for the silicide reaction can be formed due to stress introduced by the formation of the silicide, which will act upon the oxide and cause it to break up at some weak spot. The effect of phosphorus is proposed to be that it renders the oxide more viscous which prevents this process from taking place. The x-ray diffraction spectra revealed that the orientation of the grains in the polycrystalline MoSi2 films is influenced by the method of preparation.

  19. High-Temperature Annealing Induced He Bubble Evolution in Low Energy He Ion Implanted 6H-SiC

    Science.gov (United States)

    Liu, Yu-Zhu; Li, Bing-Sheng; Zhang, Li

    2017-05-01

    Bubble evolution in low energy and high dose He-implanted 6H-SiC upon thermal annealing is studied. The -oriented 6H-SiC wafers are implanted with 15 keV helium ions at a dose of 1 × 10 17 cm -2 at room temperature. The samples with post-implantation are annealed at temperatures of 1073, 1173, 1273, and 1473 K for 30 min. He bubbles in the wafers are examined via cross-sectional transmission electron microscopy (XTEM) analysis. The results present that nanoscale bubbles are almost homogeneously distributed in the damaged layer of the as-implanted sample, and no significant change is observed in the He-implanted sample after 1073 K annealing. Upon 1193 K annealing, almost full recrystallization of He-implantation-induced amorphization in 6H-SiC is observed. In addition, the diameters of He bubbles increase obviously. With continually increasing temperatures to 1273 K and 1473 K, the diameters of He bubbles increase and the number density of lattice defects decreases. The growth of He bubbles after high temperature annealing abides by the Ostwald ripening mechanism. The mean diameter of He bubbles located at depths of 120-135 nm as a function of annealing temperature is fitted in terms of a thermal activated process which yields an activation energy of 1.914+0.236 eV. Supported by the National Natural Science Foundation of China under Grant No 11475229.

  20. Improvement of Current Gain in Triple Ion Implanted 4H-SiC Bipolar Junction Transistor with Etched Extrinsic Base Regions

    Science.gov (United States)

    Tajima, Taku; Nakamura, Tadashi; Satoh, Masataka; Nakamura, Tohru

    We demonstrate triple ion implanted 4H-SiC bipolar junction transistor (BJT). By etching the extrinsic base regions using inductively coupled plasma dry etching, the characteristics of triple ion implanted 4H-SiC BJT were significantly improved. Maximum common emitter current gain was improved from 1.7 to 7.5.

  1. Enhancement-mode Ga2O3 MOSFETs with Si-ion-implanted source and drain

    Science.gov (United States)

    Wong, Man Hoi; Nakata, Yoshiaki; Kuramata, Akito; Yamakoshi, Shigenobu; Higashiwaki, Masataka

    2017-04-01

    Enhancement-mode β-Ga2O3 metal-oxide-semiconductor field-effect transistors with low series resistance were achieved by Si-ion implantation doping of the source/drain contacts and access regions. An unintentionally doped Ga2O3 channel with low background carrier concentration that was fully depleted at a gate bias of 0 V gave rise to a positive threshold voltage without additional constraints on the channel dimensions or device architecture. Transistors with a channel length of 4 µm delivered a maximum drain current density (I DS) of 1.4 mA/mm and an I DS on/off ratio near 106. Nonidealities associated with the Al2O3 gate dielectric as well as their impact on enhancement-mode device performance are discussed.

  2. Magnetic and structural properties of Fe, Ni, and Mn-implanted SiC

    CERN Document Server

    Theodoropoulou, N; Chu, S N G; Overberg, M E; Abernathy, C R; Pearton, S J; Wilson, R G; Zavada, J M; Park, Y D

    2002-01-01

    Direct implantation of Fe, Ni or Mn at doses of 3-5x10 sup 1 sup 6 cm sup - sup 2 into p-type 6H-SiC substrates was carried out at a sample temperature of approx 350 deg. C. Subsequent annealing was performed at 700-1000 deg. C for 5 mins. Residual damage in the form of end-of-range defects and dislocation loops in the region from the surface to a depth of approx 0.20 mu m were examined by transmission electron microscopy. To the sensitivity of both x-ray diffraction and selected area diffraction pattern analysis, no secondary phases could be detected. Signatures of ferromagnetism were observed in all the highest dose samples, with apparent Curie temperatures of 50 K (Ni), 250 K (Mn), and 270 K (Fe).

  3. High-voltage 4H-SiC PiN diodes with the etched implant junction termination extension

    Science.gov (United States)

    Li, Juntao; Xiao, Chengquan; Xu, Xingliang; Dai, Gang; Zhang, Lin; Zhou, Yang; Xiang, An; Yang, Yingkun; Zhang, Jian

    2017-02-01

    This paper presents the design and fabrication of an etched implant junction termination extension (JTE) for high-voltage 4H-SiC PiN diodes. Unlike the conventional JTE structure, the proposed structure utilizes multiple etching steps to achieve the optimum JTE concentration range. The simulation results show that the etched implant JTE method can improve the blocking voltage of SiC PiN diodes and also provides broad process latitude for parameter variations, such as implantation dose and activation annealing condition. The fabricated SiC PiN diodes with the etched implant JTE exhibit a highest blocking voltage of 4.5 kV and the forward on-state voltage of 4.6 V at room temperature. These results are of interest for understanding the etched implant method in the fabrication of high-voltage power devices. Project supported by the Science and Technology Development Foundation of China Academy of Engineering Physics (No. 2014A05011) and the Special Foundation of President of China Academy of Engineering Physics (No. 2014-1-100).

  4. Inspecting the surface of implanted Si(111) during annealing by reflective second harmonic generation: The influence of chamber pressure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chung-Wei; Chang, Shoou-Jinn [Institute of Microelectronics and Department of Electrical Engineering and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China); Liu, Chun-Chu [Department of Electrophysics, National Chia Yi University, Chia Yi 600, Taiwan (China); Lo, Kuang-Yao, E-mail: kuanglo@mail.ncyu.edu.tw [Department of Electrophysics, National Chia Yi University, Chia Yi 600, Taiwan (China); Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China)

    2013-02-01

    The present study used the reflective second harmonic generation (RSHG) method to analyze the quality of the surface layer of implanted Si(111) and to discuss the influence of chamber pressure during rapid thermal annealing. Under a lower chamber pressure, the recrystallization is better, and the defects are eliminated for a higher implanted dose because dopant phosphorus (P) atoms on the surface region more easily out-diffuse at lower chamber pressures. Thus, the occurrence of less out-diffusion makes more P atoms remain on the surface layer and causes larger defects, especially for higher implanted doses. Defects on the surface region are influenced by chamber pressure. In the current work, the RSHG results showed more detailed information by linking secondary ion mass spectrometry and sheet resistance measurement. - Highlights: ► Rapid thermal annealing (RTA) with different chamber pressures was performed. ► The quality of implanted Si was analyzed by reflective second harmonic generation. ► High-dose implanted Si is obviously influenced by the pressure in the RTA chamber. ► Pressure in the RTA chamber affects the generation of defects. ► Defect suppression is obvious at relatively low chamber pressure.

  5. Negative differential resistance effect induced by metal ion implantation in SiO2 film for multilevel RRAM application

    Science.gov (United States)

    Wu, Facai; Si, Shuyao; Shi, Tuo; Zhao, Xiaolong; Liu, Qi; Liao, Lei; Lv, Hangbing; Long, Shibing; Liu, Ming

    2018-02-01

    Pt/SiO2:metal nanoparticles/Pt sandwich structure is fabricated with the method of metal ion (Ag) implantation. The device exhibits multilevel storage with appropriate R off/R on ratio, good endurance and retention properties. Based on transmission electron microscopy and energy dispersive spectrometer analysis, we confirm that Pt nanoparticles are spurted into SiO2 film from Pt bottom electrode by Ag implantation; during electroforming, the local electric field can be enhanced by these Pt nanoparticles, meanwhile the Ag nanoparticles constantly migrate toward the Pt nanoparticles. The implantation induced nanoparticles act as trap sites in the resistive switching layer and play critical roles in the multilevel storage, which is evidenced by the negative differential resistance effect in the current–voltage (I–V) measurements.

  6. Formation of magnetic nanoparticles by low energy dual implantation of Ni and Fe into SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Tushara, E-mail: tusharap@gmail.com [The MacDiarmid Institute for Advanced Materials and Nanotechnology, SCPS, Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand); National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5010 (New Zealand); Williams, Grant V.M. [The MacDiarmid Institute for Advanced Materials and Nanotechnology, SCPS, Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand); Kennedy, John [The MacDiarmid Institute for Advanced Materials and Nanotechnology, SCPS, Victoria University of Wellington, PO Box 600, Wellington 6140 (New Zealand); National Isotope Centre, GNS Science, PO Box 31312, Lower Hutt 5010 (New Zealand); Rubanov, Sergey [Bio21 Institute, University of Melbourne, Victoria 3010 (Australia)

    2016-05-15

    Magnetic nanoparticles have been made by Ni and Fe implantation into a SiO{sub 2} film with a Ni:Fe ratio of 82:18 both before and after electron beam annealing (EBA). Superparamagnetic nanoparticles with diameters ∼4 nm were observed after implantation. The moment per implanted ion at high magnetic fields was significantly lower than that reported for bulk Ni{sub 1−x}Fe{sub x} with a similar x, which may be due to some implanted ions not magnetically ordering and the appearance of antiferromagnetic phases. The high field moment did not follow Bloch's T{sup 3/2} law where T is the temperature. This behaviour is likely to be due to spin-waves propagating in the nanoparticle/Ni{sub y}Fe{sub 1−y}Si{sub z}O{sub n} matrix as well as the effect of disordered spins on the surfaces of the nanoparticles. After EBA, a bimodal size distribution was observed with large isolated particles closer to the surface and smaller nanoparticles further into the film. Such a distribution has not been previously reported for similar Fe or Ni implantation. All of the Ni and Fe moments have magnetically ordered and the high field moment can be modelled using Bloch's law and a small contribution from disordered moments in the shell with an average thickness of ∼0.3 nm. - Highlights: • First study of dual Ni and Fe low-energy ion implantation into SiO{sub 2}. • Small superparamagnetic nanoparticles are observed after implantation. • These nanoparticles do not follow Bloch T{sup 3/2} law. • Electron beam annealing leads to a bimodal size distribution and magnetic ordering. • A spin-glass from uncompensated moments at the nanoparticle surface was observed.

  7. Cadaveric feasibility study of da Vinci Si-assisted cochlear implant with augmented visual navigation for otologic surgery.

    Science.gov (United States)

    Liu, Wen P; Azizian, Mahdi; Sorger, Jonathan; Taylor, Russell H; Reilly, Brian K; Cleary, Kevin; Preciado, Diego

    2014-03-01

    To our knowledge, this is the first reported cadaveric feasibility study of a master-slave-assisted cochlear implant procedure in the otolaryngology-head and neck surgery field using the da Vinci Si system (da Vinci Surgical System; Intuitive Surgical, Inc). We describe the surgical workflow adaptations using a minimally invasive system and image guidance integrating intraoperative cone beam computed tomography through augmented reality. To test the feasibility of da Vinci Si-assisted cochlear implant surgery with augmented reality, with visualization of critical structures and facilitation with precise cochleostomy for electrode insertion. Cadaveric case study of bilateral cochlear implant approaches conducted at Intuitive Surgical Inc, Sunnyvale, California. Bilateral cadaveric mastoidectomies, posterior tympanostomies, and cochleostomies were performed using the da Vinci Si system on a single adult human donor cadaveric specimen. Radiographic confirmation of successful cochleostomies, placement of a phantom cochlear implant wire, and visual confirmation of critical anatomic structures (facial nerve, cochlea, and round window) in augmented stereoendoscopy. With a surgical mean time of 160 minutes per side, complete bilateral cochlear implant procedures were successfully performed with no violation of critical structures, notably the facial nerve, chorda tympani, sigmoid sinus, dura, or ossicles. Augmented reality image overlay of the facial nerve, round window position, and basal turn of the cochlea was precise. Postoperative cone beam computed tomography scans confirmed successful placement of the phantom implant electrode array into the basal turn of the cochlea. To our knowledge, this is the first study in the otolaryngology-head and neck surgery literature examining the use of master-slave-assisted cochleostomy with augmented reality for cochlear implants using the da Vinci Si system. The described system for cochleostomy has the potential to improve the

  8. Ion-implanted Si-nanostructures buried in a SiO{sub 2} substrate studied with soft-x-ray spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R.; Rubensson, J.E.; Eisebitt, S. [Forschungszentrum Juelich (Germany)] [and others

    1997-04-01

    In recent years silicon nanostructures have gained great interest because of their optical luminescence, which immediately suggests several applications, e.g., in optoelectronic devices. Nanostructures are also investigated because of the fundamental physics involved in the underlying luminescence mechanism, especially attention has been drawn to the influence of the reduced dimensions on the electronic structure. The forming of stable and well-defined nanostructured materials is one goal of cluster physics. For silicon nanostructures this goal has so far not been reached, but various indirect methods have been established, all having the problem of producing less well defined and/or unstable nanostructures. Ion implantation and subsequent annealing is a promising new technique to overcome some of these difficulties. In this experiment the authors investigate the electronic structure of ion-implanted silicon nanoparticles buried in a stabilizing SiO{sub 2} substrate. Soft X-ray emission (SXE) spectroscopy features the appropriate information depth to investigate such buried structures. SXE spectra to a good approximation map the local partial density of occupied states (LPDOS) in broad band materials like Si. The use of monochromatized synchrotron radiation (MSR) allows for selective excitation of silicon atoms in different chemical environments. Thus, the emission from Si atom sites in the buried structure can be separated from contributions from the SiO{sub 2} substrate. In this preliminary study strong size dependent effects are found, and the electronic structure of the ion-implanted nanoparticles is shown to be qualitatively different from porous silicon. The results can be interpreted in terms of quantum confinement and chemical shifts due to neighboring oxygen atoms at the interface to SiO{sub 2}.

  9. Efficient 1535 nm light emission from an all-Si-based optical micro-cavity containing Er³⁺ and Yb³⁺ ions.

    Science.gov (United States)

    Gallo, I B; Braud, A; Zanatta, A R

    2013-11-18

    This work reports on the construction and spectroscopic analyses of optical micro-cavities (OMCs) that efficiently emit at ~1535 nm. The emission wavelength matches the third transmission window of commercial optical fibers and the OMCs were entirely based on silicon. The sputtering deposition method was adopted in the preparation of the OMCs, which comprised two Bragg reflectors and one spacer layer made of either Er- or ErYb-doped amorphous silicon nitride. The luminescence signal extracted from the OMCs originated from the 4I(13/2)→ions) and its intensity showed to be highly dependent on the presence of Yb3+ ions. According to the results, the Er3+-related light emission was improved by a factor of 48 when combined with Yb3+ ions and inserted in the spacer layer of the OMC. The results also showed the effectiveness of the present experimental approach in producing Si-based light-emitting structures in which the main characteristics are: (a) compatibility with the actual micro-electronics industry, (b) the deposition of optical quality layers with accurate composition control, and (c) no need of uncommon elements-compounds nor extensive thermal treatments. Along with the fundamental characteristics of the OMCs, this work also discusses the impact of the Er3+-Yb3+ ion interaction on the emission intensity as well as the potential of the present findings.

  10. In vitro and in vivo evaluation of zinc-modified ca-si-based ceramic coating for bone implants.

    Directory of Open Access Journals (Sweden)

    Jiangming Yu

    Full Text Available The host response to calcium silicate ceramic coatings is not always favorable because of their high dissolution rates, leading to high pH within the surrounding physiological environment. Recently, a zinc-incorporated calcium silicate-based ceramic Ca2ZnSi2O7 coating, developed on a Ti-6Al-4V substrate using plasma-spray technology, was found to exhibit improved chemical stability and biocompatibility. This study aimed to investigate and compare the in vitro response of osteoblastic MC3T3-E1 cells cultured on Ca2ZnSi2O7 coating, CaSiO3 coating, and uncoated Ti-6Al-4V titanium control at cellular and molecular level. Our results showed Ca2ZnSi2O7 coating enhanced MC3T3-E1 cell attachment, proliferation, and differentiation compared to CaSiO3 coating and control. In addition, Ca2ZnSi2O7 coating increased mRNA levels of osteoblast-related genes (alkaline phosphatase, procollagen α1(I, osteocalcin, insulin-like growth factor-I (IGF-I, and transforming growth factor-β1 (TGF-β1. The in vivo osteoconductive properties of Ca2ZnSi2O7 coating, compared to CaSiO3 coating and control, was investigated using a rabbit femur defect model. Histological and histomorphometrical analysis demonstrated new bone formation in direct contact with the Ca2ZnSi2O7 coating surface in absence of fibrous tissue and higher bone-implant contact rate (BIC in the Ca2ZnSi2O7 coating group, indicating better biocompatibility and faster osseointegration than CaSiO3 coated and control implants. These results indicate Ca2ZnSi2O7 coated implants have applications in bone tissue regeneration, since they are biocompatible and able to osseointegrate with host bone.

  11. An unconventional ion implantation method for producing Au and Si nanostructures using intense laser-generated plasmas

    Science.gov (United States)

    Torrisi, L.; Cutroneo, M.; Mackova, A.; Lavrentiev, V.; Pfeifer, M.; Krousky, E.

    2016-02-01

    The present paper describes measurements of ion implantation by high-intensity lasers in an innovative configuration. The ion acceleration and implantation were performed using the target normal sheath acceleration regime. Highly ionized charged ions were generated and accelerated by the self-consistent electrostatic accelerating field at the rear side of a directly illuminated foil surface. A sub-nanosecond pulsed laser operating at an intensity of about 1016 W cm-2 was employed to irradiate thin foils containing Au atoms. Multi-energy and multi-species ions with energies of the order of 1 MeV per charge state were implanted on exposed substrates of monocrystalline silicon up to a concentration of about 1% Au atoms in the first superficial layers. The target, laser parameters and irradiation conditions play a decisive role in the dynamic control of the characteristics of the ion beams to be implanted. The ion penetration depth, the depth profile, the integral amount of implanted ions and the concentration-depth profiles were determined by Rutherford back-scattering analysis. Ion implantation produces Si nanocrystals and Au nanoparticles and induces physical and chemical modifications of the implanted surfaces.

  12. Distance Dependence of Gold-Enhanced Upconversion luminescence in Au/SiO2/Y2O3:Yb3+, Er3+ Nanoparticles

    Science.gov (United States)

    Ge, W.; Zhang, X. R.; Liu, M.; Lei, Z. W.; Knize, R. J.; Lu, Yalin

    2013-01-01

    We report a localized surface plasmon enhanced upconversion luminescence in Au/SiO2/Y2O3:Yb3+,Er3+ nanoparticles when excited at 980 nm. By adjusting the silica spacer's thickness, a maximum 9.59-fold enhancement of the green emission was obtained. Effect of the spacer distance on the Au-Y2O3:Yb3+, Er3+ green upconversion mechanism was numerically simulated and experimentally demonstrated. In theory for radiative decay and excitation rates, they can be largely enhanced at the spacer thicknesses of less than 70 and 75 nm, respectively, and the quenching can be caused by the non-radiative energy transferring at the distance of less than 55 nm. PMID:23606915

  13. Upconversion induced enhancement of dye sensitized solar cells based on core-shell structured β-NaYF4:Er3+, Yb3+@SiO2 nanoparticles.

    Science.gov (United States)

    Zhou, Ziyao; Wang, Jiahong; Nan, Fan; Bu, Chenghao; Yu, Zhenhua; Liu, Wei; Guo, Shishang; Hu, Hao; Zhao, Xing-Zhong

    2014-02-21

    Upconversion materials have been employed as energy relay materials in dye sensitized solar cells (DSCs) to broaden the range of light absorption. However, the origin of the enhancements can be induced by both upconversion and size-dependent light scattering effects. To clarify the role of the upconversion material in the photoelectrode of DSCs, an upconversion induced device was realized here, which has the size-dependent light scattering effect eliminated via the application of NaYF4:Er(3+), Yb(3+)@SiO2 upconversion nanoparticles (β-NYEY@SiO2 UCNPs). An enhancement of 6% in efficiency was observed for the device. This demonstration provided an insight into the possible further employment of upconversion in DSCs.

  14. The post-annealing temperature dependences of electrical properties and surface morphologies for arsenic ion-implanted 4H-SiC at high temperature

    Science.gov (United States)

    Senzaki, J.; Fukuda, K.; Imai, S.; Tanaka, Y.; Kobayashi, N.; Tanoue, H.; Okushi, H.; Arai, K.

    2000-06-01

    High-temperature ion implantation of arsenic (As +) into the 4H-silicon carbide (SiC) substrates with high dose of 7×10 15 cm -2 has been investigated as an effective doping method of n-type dopant for SiC power electron devices fabrication. Regardless of the ion implantation temperature, the sheet resistances ( Rs) decrease below 1600°C post-annealing and increase above 1700°C as the post-annealing temperature increases. The low Rs value (213 Ω/□) is achieved in the sample implanted at 500°C and annealed at 1600°C, an order of magnitude smaller than that implanted at room temperature (RT). Atomic force microscopy (AFM) images reveal that the surface roughness of ion-implanted SiC increases with the increase of post-annealing temperature. Secondary ion mass spectroscopy (SIMS) results show that As + dopant depth profiles of the sample implanted at 500°C do not change before and after the post-annealing. On the other hand, for the sample implanted at RT, the As + concentration in the ion-implanted layer decreases due to the outer-diffusion. These results indicate that high-temperature ion implantation is an effective method to prevent the outer-diffusion of As + dopants during high-temperature post-annealing. It is considered that these post-annealing temperature dependences are caused by the evaporation of SiC surface layer.

  15. Threshold switching in SiGeAsTeN chalcogenide glass prepared by As ion implantation into sputtered SiGeTeN film

    Science.gov (United States)

    Liu, Guangyu; Wu, Liangcai; Song, Zhitang; Liu, Yan; Li, Tao; Zhang, Sifan; Song, Sannian; Feng, Songlin

    2017-12-01

    A memory cell composed of a selector device and a storage device is the basic unit of phase change memory. The threshold switching effect, main principle of selectors, is a universal phenomenon in chalcogenide glasses. In this work, we put forward a safe and controllable method to prepare a SiGeAsTeN chalcogenide film by implanting As ions into sputtered SiGeTeN films. For the SiGeAsTeN material, the phase structure maintains the amorphous state, even at high temperature, indicating that no phase transition occurs for this chalcogenide-based material. The electrical test results show that the SiGeAsTeN-based devices exhibit good threshold switching characteristics and the switching voltage decreases with the increasing As content. The decrease in valence alternation pairs, reducing trap state density, may be the physical mechanism for lower switch-on voltage, which makes the SiGeAsTeN material more applicable in selector devices through component optimization.

  16. Photoluminescence and structural studies of Tb and Eu implanted at high temperatures into SiO{sub 2} films

    Energy Technology Data Exchange (ETDEWEB)

    Bregolin, F.L. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970, Porto Alegre-RS (Brazil); Sias, U.S., E-mail: uilson.sias@gmail.com [Instituto Federal Sul-rio-grandense, Campus Pelotas, Praca 20 de Setembro 455, 96015-360, Pelotas-RS (Brazil); Behar, M. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970, Porto Alegre-RS (Brazil)

    2013-03-15

    The present work deals with the photoluminescence (PL) emitted from Eu and Tb ions implanted at room temperature (RT) up to 350 Degree-Sign C in a SiO{sub 2} matrix, followed by a further anneal process. The ions were implanted with energy of 100 keV and a fluence of 3 Multiplication-Sign 10{sup 15} ions/cm Superscript-Two . Further anneals were performed in atmospheres of N{sub 2} or O{sub 2} with temperatures ranging from 500 up to 800 Degree-Sign C. PL measurements were performed at RT and structural measurements were done via transmission electron microscopy (TEM). In addition, the Rutherford backscattering technique (RBS) was used to investigate the corresponding ion depth profiles. For Tb, the optimal implantation temperature was 200 Degree-Sign C, and the anneal one was of 500 Degree-Sign C. Under these conditions, the PL yield of the sharp band centered at 550 nm was significatively higher than the one obtained with RT implants. The PL spectra corresponding to the Eu ions show two bands, one narrow centered around 650 nm and a second broad one in the blue-green region. The implantation temperature plays a small influence on the PL shape and yield. However, the annealing atmosphere has a strong influence on it. Samples annealed in N{sub 2} present a broad PL band, ranging from 370 up to 840 nm. On the other hand, the O{sub 2} anneal conserves the original as-implanted spectrum, that is: a broad PL band in the blue-green region together with sharp PL band in the red one. For both ions, Tb and Eu, the TEM analyses indicate the formation of nanoclusters in the hot as-implanted samples. - Highlights: Black-Right-Pointing-Pointer Eu and Tb nanoparticles were obtained by hot ion implantation into SiO{sub 2} matrix. Black-Right-Pointing-Pointer TEM results indicate the formation of nanoclusters in the hot as-implanted samples. Black-Right-Pointing-Pointer Samples annealed in N{sub 2} presented a broad PL band (from 370 up to 840 nm). Black-Right-Pointing-Pointer O

  17. Order-of-magnitude differences in retention of low-energy Ar implanted in Si and SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Wittmaack, Klaus, E-mail: wittmaack@helmholtz-muenchen.de [Helmholtz Zentrum München, Institute of Radiation Protection, D-85758 Neuherberg (Germany); Giordani, Andrew; Umbel, Rachel [Nanoscale Characterization and Fabrication Laboratory, Virginia Polytechnic Institute and State University, 1991 Kraft Dr., Blacksburg, Virginia 24060 and Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, 445 Old Turner St., Blacksburg, Virginia 24060 (United States); Hunter, Jerry L. [Nanoscale Characterization and Fabrication Laboratory, Virginia Polytechnic Institute and State University, 1991 Kraft Dr., Blacksburg, Virginia 24060 (United States); Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, 445 Old Turner St., Blacksburg, Virginia 24060 (United States); and Materials Science Center, University of Wisconsin-Madison, 1509 University Avenue, Madison, Wisconsin 53706 (United States)

    2016-09-15

    The retention of 1 and 5 keV Ar implanted at 45° in Si and 4.3 nm SiO{sub 2} on Si was studied at fluences between 3 × 10{sup 14} and 1.5 × 10{sup 16} cm{sup −2}. X-ray photoelectron spectroscopy (XPS) served to monitor the accumulation of Ar as well as the removal of SiO{sub 2}. Bombardment induced changes in oxygen chemistry caused the O 1s peak position to move toward lower binding energies by as much as 2.2 eV. Plotted versus depth of erosion, the fluence dependent changes in oxygen content, and peak position were similar at 1 and 5 keV. The Ar content of Si increased with increasing exposure, saturating at fluences of ∼2 × 10{sup 15} cm{sup −2} (1 keV) and ∼6 × 10{sup 15} cm{sup −2} (5 keV). Much less Ar was retained in the SiO{sub 2}/Si sample, notably at 1 keV, in which case the low-fluence Ar signal amounted to only 8% of the Si reference. The results imply that essentially no Ar was trapped in undamaged SiO{sub 2}, i.e., the Ar atoms initially observed by XPS were located underneath the oxide. At the lowest fluence of 5 keV Ar, the retention ratio was much higher (43%) because the oxide was already highly damaged, with an associated loss of oxygen. The interpretation was assisted by TRIM(SRIM) calculations of damage production. Partial maloperation of the ion beam raster unit, identified only at a late stage of this work, enforced a study on the uniformity of bombardment. The desired information could be obtained by determining x,y line scan profiles of O 1s across partially eroded SiO{sub 2}/Si samples. Fluence dependent Ar retention in Si was described using an extended version of the rapid relocation model which takes into account that insoluble implanted rare-gas atoms tend to migrate to the surface readily under ongoing bombardment. The range parameters required for the modeling were determined using TRIM(SRIM); sputtering yields were derived from the literature. The other three parameters

  18. Nanoscale electro-structural characterisation of ohmic contacts formed on p-type implanted 4H-SiC

    Directory of Open Access Journals (Sweden)

    Saggio Mario

    2011-01-01

    Full Text Available Abstract This work reports a nanoscale electro-structural characterisation of Ti/Al ohmic contacts formed on p-type Al-implanted silicon carbide (4H-SiC. The morphological and the electrical properties of the Al-implanted layer, annealed at 1700°C with or without a protective capping layer, and of the ohmic contacts were studied using atomic force microscopy [AFM], transmission line model measurements and local current measurements performed with conductive AFM. The characteristics of the contacts were significantly affected by the roughness of the underlying SiC. In particular, the surface roughness of the Al-implanted SiC regions annealed at 1700°C could be strongly reduced using a protective carbon capping layer during annealing. This latter resulted in an improved surface morphology and specific contact resistance of the Ti/Al ohmic contacts formed on these regions. The microstructure of the contacts was monitored by X-ray diffraction analysis and a cross-sectional transmission electron microscopy, and correlated with the electrical results.

  19. Distinct itinerant spin-density waves and local-moment antiferromagnetism in an intermetallic ErPd2Si2 single crystal.

    Science.gov (United States)

    Li, Hai-Feng; Cao, Chongde; Wildes, Andrew; Schmidt, Wolfgang; Schmalzl, Karin; Hou, Binyang; Regnault, Louis-Pierre; Zhang, Cong; Meuffels, Paul; Löser, Wolfgang; Roth, Georg

    2015-01-22

    Identifying the nature of magnetism, itinerant or localized, remains a major challenge in condensed-matter science. Purely localized moments appear only in magnetic insulators, whereas itinerant moments more or less co-exist with localized moments in metallic compounds such as the doped-cuprate or the iron-based superconductors, hampering a thorough understanding of the role of magnetism in phenomena like superconductivity or magnetoresistance. Here we distinguish two antiferromagnetic modulations with respective propagation wave vectors at Q± = (H ± 0.557(1), 0, L ± 0.150(1)) and QC = (H ± 0.564(1), 0, L), where (H, L) are allowed Miller indices, in an ErPd2Si2 single crystal by neutron scattering and establish their respective temperature- and field-dependent phase diagrams. The modulations can co-exist but also compete depending on temperature or applied field strength. They couple differently with the underlying lattice albeit with associated moments in a common direction. The Q± modulation may be attributed to localized 4f moments while the QC correlates well with itinerant conduction bands, supported by our transport studies. Hence, ErPd2Si2 represents a new model compound that displays clearly-separated itinerant and localized moments, substantiating early theoretical predictions and providing a unique platform allowing the study of itinerant electron behavior in a localized antiferromagnetic matrix.

  20. Mn fraction substitutional site and defects induced magnetism in Mn-implanted 6H-SiC

    Energy Technology Data Exchange (ETDEWEB)

    Bouziane, K., E-mail: Khalid.bouziane@uir.ac.ma [Pôle Energies Renouvelables et Etudes Pétrolières, Université Internationale de Rabat, 11000 – Salé el Jadida, Technopolis (Morocco); Al Azri, M.; Elzain, M. [Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Al-Khodh 123 (Oman); Chérif, S.M. [LSPM (CNRS-UPR 3407), Université Paris, 13-Nord, 99, Avenue Jean Baptiste Clément, 93430 Villetaneuse (France); Mamor, M. [Equipe MSISM, Faculté Poly-Disciplinaire, B.P. 4162 Safi, Université Cadi Ayyad, Marrakech (Morocco); Declémy, A. [Institut P’, CNRS – Université de Poitiers – ENSMA, UPR 3346, SP2MI – Téléport 2, 11 boulevard Marie et Pierre Curie, BP 30179, F-86962 Futuroscope Chasseneuil Cedex (France); Thomé, L. [CSNSM-Orsay, Bât. 108, Université d’Orsay, F-91405 Orsay (France)

    2015-05-25

    Highlights: • Shallow Mn-implanted 6H-SiC crystal. • Correlation between Mn-substitutional site concentration and magnetism. • Correlation between defects nature surrounding Mn site and magnetism. • Correlation of magnetism in Mn-doped SiC to Mn at Si sites and vacancy-related defect. - Abstract: n-type 6H-SiC (0 0 0 1) single crystal substrates were implanted with three fluences of manganese (Mn{sup +}) ions: 5 × 10{sup 15}, 1 × 10{sup 16} and 5 × 10{sup 16} cm{sup −2} with implantation energy of 80 keV at 365 °C to stimulate dynamic annealing. The samples were characterized using Rutherford backscattering channeling spectroscopy (RBS/C), high-resolution X-ray diffraction technique (HRXRD), and Superconducting Quantum Interference Device (SQUID) techniques. Two main defect regions have been identified using RBS/C spectra fitted with the McChasy code combined to SRIM simulations. Intermediate defects depth region is associated with vacancies (D{sub V}) and deeper defect (D{sub N}) essentially related to the Si and C interstitial defects. The defect concentration and the maximum perpendicular strain exhibit similar increasing trend with the Mn{sup +} fluence. Furthermore, the amount of Mn atoms at Si substitutional sites and the corresponding magnetic moment per Mn atom were found to increase with increasing Mn fluence from 0.7 μ{sub B} to 1.7 μ{sub B} and then collapsing to 0.2 μ{sub B}. Moreover, a strong correlation has been found between the magnetic moment and the combination of both large D{sub V}/D{sub N} ratio and high Mn at Si sites. These results are corroborated by our ab initio calculations considering the most stable configurations showing that besides the amount of Mn substituting Si sites, local vacancy-rich environment is playing a crucial role in enhancing the magnetism.

  1. Effect of ion implantation energy for the synthesis of Ge nanocrystals in SiN films with HfO2/SiO2 stack tunnel dielectrics for memory application

    Directory of Open Access Journals (Sweden)

    Gloux Florence

    2011-01-01

    Full Text Available Abstract Ge nanocrystals (Ge-NCs embedded in SiN dielectrics with HfO2/SiO2 stack tunnel dielectrics were synthesized by utilizing low-energy (≤5 keV ion implantation method followed by conventional thermal annealing at 800°C, the key variable being Ge+ ion implantation energy. Two different energies (3 and 5 keV have been chosen for the evolution of Ge-NCs, which have been found to possess significant changes in structural and chemical properties of the Ge+-implanted dielectric films, and well reflected in the charge storage properties of the Al/SiN/Ge-NC + SiN/HfO2/SiO2/Si metal-insulator-semiconductor (MIS memory structures. No Ge-NC was detected with a lower implantation energy of 3 keV at a dose of 1.5 × 1016 cm-2, whereas a well-defined 2D-array of nearly spherical and well-separated Ge-NCs within the SiN matrix was observed for the higher-energy-implanted (5 keV sample for the same implanted dose. The MIS memory structures implanted with 5 keV exhibits better charge storage and retention characteristics compared to the low-energy-implanted sample, indicating that the charge storage is predominantly in Ge-NCs in the memory capacitor. A significant memory window of 3.95 V has been observed under the low operating voltage of ± 6 V with good retention properties, indicating the feasibility of these stack structures for low operating voltage, non-volatile memory devices.

  2. Observation of Sb sub 2 O sub 3 nanocrystals in SiO sub 2 after Sb ion implantation

    CERN Document Server

    Ignatova, V A; Gijbels, R; Adams, F; Lebedev, O I; Landuyt, J V; Waetjen, U

    2002-01-01

    Antimony nanocrystals were formed in thin SiO sub 2 films using low-energy ion implantation of Sb followed by annealing. Using Fourier transform laser microprobe mass spectrometry (FT LMMS), we observed for the first time the presence of antimony oxide in the intermediate phase (as-implanted layer of Sb) by means of signals referring to the intact Sb sub 2 O sub 3 molecules. Only SbO sup + fragments, but no adduct ions of Sb sub 2 O sub 3 could be detected in annealed samples. The size and the distribution of the nanocrystals formed around the initial depth of implantation were studied in the as-implanted samples by high-resolution electron microscopy (HREM). The crystalline structure of these nanocrystals was also studied and the presence of antimony trioxide Sb sub 2 O sub 3 in the form of valentinite was proven. After the annealing step, the implanted material had spread into a wider band. The method introduced here, based on combining TEM (transmission electron microscopy) and FT LMMS results, offers the ...

  3. Ion-implantation and analysis for doped silicon slot waveguides

    Directory of Open Access Journals (Sweden)

    McCallum J. C.

    2012-10-01

    Full Text Available We have utilised ion implantation to fabricate silicon nanocrystal sensitised erbium-doped slot waveguide structures in a Si/SiO2/Si layered configuration and photoluminescence (PL and Rutherford backscattering spectrometry (RBS to analyse these structures. Slot waveguide structures in which light is confined to a nanometre-scale low-index region between two high-index regions potentially offer significant advantages for realisation of electrically-pumped Si devices with optical gain and possibly quantum optical devices. We are currently investigating an alternative pathway in which high quality thermal oxides are grown on silicon and ion implantation is used to introduce the Er and Si-ncs into the SiO2 layer. This approach provides considerable control over the Er and Si-nc concentrations and depth profiles which is important for exploring the available parameter space and developing optimised structures. RBS is well-suited to compositional analysis of these layered structures. To improve the depth sensitivity we have used a 1 MeV α beam and results indicate that a layered silicon-Er:SiO2/silicon structure has been fabricated as desired. In this paper structural results will be compared to Er photoluminescence profiles for samples processed under a range of conditions.

  4. Depth dependent modification of optical constants arising from H+ implantation in n-type 4H-SiC measured using coherent acoustic phonons

    Directory of Open Access Journals (Sweden)

    Andrey Baydin

    2016-06-01

    Full Text Available Silicon carbide (SiC is a promising material for new generation electronics including high power/high temperature devices and advanced optical applications such as room temperature spintronics and quantum computing. Both types of applications require the control of defects particularly those created by ion bombardment. In this work, modification of optical constants of 4H-SiC due to hydrogen implantation at 180 keV and at fluences ranging from 1014 to 1016 cm−2 is reported. The depth dependence of the modified optical constants was extracted from coherent acoustic phonon spectra. Implanted spectra show a strong dependence of the 4H-SiC complex refractive index depth profile on H+ fluence. These studies provide basic insight into the dependence of optical properties of 4H silicon carbide on defect densities created by ion implantation, which is of relevance to the fabrication of SiC-based photonic and optoelectronic devices.

  5. Zn-vapor diffused Er:Yb:LiNbO 3 channel waveguides fabricated by means of SiO 2 electron cyclotron resonance plasma deposition

    Science.gov (United States)

    Pernas, P. L.; Hernández, M. J.; Ruíz, E.; Cantelar, E.; Nevado, R.; Morant, C.; Lifante, G.; Cussó, F.

    2000-07-01

    We report here the fabrication method and operation of Zinc-vapor diffused channel waveguides on Erbium/Ytterbium (Er/Yb)-doped Lithium Niobate (LiNbO 3). electron cyclotron resonance (ECR) plasma deposition technique, UV photolithography and Reactive Ion Etching (RIE) are used to define an SiO 2 mask for pattern transfer. The whole process is performed at low temperatures eliminating typical LiO 2 out-diffusion problems and achieving low surface damage. The flexibility of the fabrication technology has been shown to be potentially applicable to integrated optics. EDAX measurements reveal good confinement and homogeneity of the diffused regions. Atomic Force Microscopy (AFM) surface characterization shows the swelling of the diffused areas, consistent with the topoepitaxial growth of a Zn xLi yNb zO w layer.

  6. Broadband mid-IR frequency comb with CdSiP2 and AgGaS2 from an Er,Tm:Ho fiber laser.

    Science.gov (United States)

    Sánchez, D; Hemmer, M; Baudisch, M; Zawilski, K; Schunemann, P; Hoogland, H; Holzwarth, R; Biegert, J

    2014-12-15

    We report on the generation of a 2500 nm bandwidth frequency comb at 6.5 μm central wavelength based on critically phase-matched parametric down-conversion in the nonlinear crystal CdSiP(2) (CSP), driven by a compact Er,Tm:Ho fiber laser. The generated ultra-broadband pulses show a transform-limited duration of 2.3 optical cycles and carry up to 150 pJ of energy at a 100 MHz pulse repetition rate. For comparison, the spectrum generated in AgGaS(2) (AGS) spans from 6.2 to 7.4 μm at full-width at half-maximum (FWHM) with a pulse energy of 3 pJ. A full 3D nonlinear wave propagation code is used for optimization of the noncollinear angle, propagation direction, and crystal thickness.

  7. Implantation of plasmonic nanoparticles in SiO{sub 2} by pulsed laser irradiation of gold films on SiO{sub x}-coated fused silica and subsequent thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Stolzenburg, H. [Laser-Laboratorium Göttingen, Hans-Adolf-Krebs-Weg 1, 37077 Göttingen (Germany); Peretzki, P.; Wang, N.; Seibt, M. [IV. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Ihlemann, J., E-mail: juergen.ihlemann@llg-ev.de [Laser-Laboratorium Göttingen, Hans-Adolf-Krebs-Weg 1, 37077 Göttingen (Germany)

    2016-06-30

    Highlights: • Gold nanoparticles are implanted in glass by pulsed UV-laser irradiation. • Implantation of gold into SiO{sub x} and annealing leads to Au-particles in quartz glass. • TEM investigations reveal particles with 10–60 nm diameter in a depth of 40 nm. • Implanted particles show plasmon resonance at 540 nm. - Abstract: The pulsed UV-laser irradiation of thin noble metal films deposited on glass substrates leads to the incorporation of metal particles in the glass, if a sufficiently high laser fluence is applied. This process is called laser implantation. For the implantation of gold into pure fused silica, high laser fluences (∼1 J/cm{sup 2} at 193 nm laser wavelength) are required. Using a SiO{sub x} (x ≈ 1) coated SiO{sub 2}-substrate, the implantation of gold into this coating can be accomplished at significantly lower fluences starting from 0.2 J/cm{sup 2} (comparable to those used for standard glass). Particles with diameters in the range of 10–60 nm are implanted to a depth of about 40 nm as identified by transmission electron microscopy. An additional high temperature annealing step in air leads to the oxidation of SiO{sub x} to SiO{sub 2}, without influencing the depth distribution of particles significantly. Only superficial, weakly bound particles are released and can be wiped away. Absorption spectra show a characteristic plasmon resonance peak at 540 nm. Thus, pure silica glass (SiO{sub 2}) with near surface incorporated plasmonic particles can be fabricated with this method. Such material systems may be useful for example as robust substrates for surface enhanced Raman spectroscopy (SERS).

  8. Analytical threshold voltage modeling of ion-implanted strained-Si double-material double-gate (DMDG) MOSFETs

    Science.gov (United States)

    Goel, Ekta; Singh, Balraj; Kumar, Sanjay; Singh, Kunal; Jit, Satyabrata

    2017-04-01

    Two dimensional threshold voltage model of ion-implanted strained-Si double-material double-gate MOSFETs has been done based on the solution of two dimensional Poisson's equation in the channel region using the parabolic approximation method. Novelty of the proposed device structure lies in the amalgamation of the advantages of both the strained-Si channel and double-material double-gate structure with a vertical Gaussian-like doping profile. The effects of different device parameters (such as device channel length, gate length ratios, germanium mole fraction) and doping parameters (such as projected range, straggle parameter) on threshold voltage of the proposed structure have been investigated. It is observed that the subthreshold performance of the device can be improved by simply controlling the doping parameters while maintaining other device parameters constant. The modeling results show a good agreement with the numerical simulation data obtained by using ATLAS™, a 2D device simulator from SILVACO.

  9. Characterization of interface traps in stable and efficient Tb-implanted SiO{sub 2} light-emitting devices

    Energy Technology Data Exchange (ETDEWEB)

    Seeger, Michael; Rebohle, Lars; Lehmann, Jan; Skorupa, Wolfgang; Helm, Manfred; Schmidt, Heidemarie [Forschungszentrum Dresden-Rossendorf e.V., Dresden (Germany)

    2010-07-01

    The strong green electroluminescence from the Tb{sup 3+} ions in SiO{sub 2} is excited by hot electrons from the conduction band of the SiO{sub 2} matrix in metal oxide semiconductor light emitting devices (MOSLED). Charge trapping in the oxide layers and at the oxide layer-semiconductor interface cause a short lifetime of the MOSLED. This has been investigated by means of frequency dependent admittance-voltage measurements to determine if the MOSLED will perform satisfactorily for different annealing times. Our results on unimplanted MOSLEDs reveal the largest interface trap density of 10{sup 13} eV{sup -1} cm{sup -2} for 60 s rapid thermal annealing at 1000 C. Also the effect of Tb{sup +} implantation on interface trap properties in MOSLEDs containing double-stacked dielectric layers has been investigated. Quasistatic charge-voltage (QV) measurements have been used to probe the interface trap occupancy versus voltage.

  10. Energy levels, oscillator strengths, line strengths, and transition probabilities in Si-like ions of La XLIII, Er LIV, Tm LV, and Yb LVI

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhan-Bin, E-mail: chenzb008@qq.com [College of Science, National University of Defense Technology, Changsha, Hunan 410073 (China); Ma, Kun [School of Information Engineering, Huangshan University, Huangshan 245041 (China); Wang, Hong-Jian [Chongqing Key Laboratory for Design and Control of Manufacturing Equipment, Chongqing Technology and Business University, Chongqing 40067 (China); Wang, Kai, E-mail: wangkai@hbu.edu.cn [Hebei Key Lab of Optic-electronic Information and Materials, The College of Physics Science and Technology, Hebei University, Baoding 071002 (China); Liu, Xiao-Bin [Department of Physics, Tianshui Normal University, Tianshui 741001 (China); Zeng, Jiao-Long [College of Science, National University of Defense Technology, Changsha, Hunan 410073 (China)

    2017-01-15

    Detailed calculations using the multi-configuration Dirac–Fock (MCDF) method are carried out for the lowest 64 fine-structure levels of the 3s{sup 2}3p{sup 2}, 3s{sup 2}3p3d, 3s3p{sup 3}, 3s3p{sup 2}3d, 3s{sup 2}3d{sup 2}, and 3p{sup 4} configurations in Si-like ions of La XLIII, Er LIV, Tm LV, and Yb LVI. Energies, oscillator strengths, wavelengths, line strengths, and radiative electric dipole transition rates are given for all ions. A parallel calculation using the many-body perturbation theory (MBPT) method is also carried out to assess the present energy levels accuracy. Comparisons are performed between these two sets of energy levels, as well as with other available results, showing that they are in good agreement with each other within 0.5%. These high accuracy results can be used to the modeling and the interpretation of astrophysical objects and fusion plasmas. - Highlights: • Energy levels and E1 transition rates of Si-like ions are presented. • Breit interaction and Quantum Electrodynamics effects are discussed. • Present results should be useful in the astrophysical application and plasma modeling.

  11. Multifunctional NaYF4:Yb, Er@mSiO2@Fe3O4-PEG nanoparticles for UCL/MR bioimaging and magnetically targeted drug delivery.

    Science.gov (United States)

    Liu, Bei; Li, Chunxia; Ma, Ping'an; Chen, Yinyin; Zhang, Yuanxin; Hou, Zhiyao; Huang, Shanshan; Lin, Jun

    2015-02-07

    A low toxic multifunctional nanoplatform, integrating both mutimodal diagnosis methods and antitumor therapy, is highly desirable to assure its antitumor efficiency. In this work, we show a convenient and adjustable synthesis of multifunctional nanoparticles NaYF4:Yb, Er@mSiO2@Fe3O4-PEG (MFNPs) based on different sizes of up-conversion nanoparticles (UCNPs). With strong up-conversion fluorescence offered by UCNPs, superparamagnetism properties attributed to Fe3O4 nanoparticles and porous structure coming from the mesoporous SiO2 shell, the as-obtained MFNPs can be utilized not only as a contrast agent for dual modal up-conversion luminescence (UCL)/magnetic resonance (MR) bio-imaging, but can also achieve an effective magnetically targeted antitumor chemotherapy both in vitro and in vivo. Furthermore, the UCL intensity of UCNPs and the magnetic properties of Fe3O4 in the MFNPs were carefully balanced. Silica coating and further PEG modifying can improve the hydrophilicity and biocompatibility of the as-synthesized MFNPs, which was confirmed by the in vitro/in vivo biocompatibility and in vivo long-time bio-distributions tests. Those results revealed that the UCNPs based magnetically targeted drug carrier system we synthesized has great promise in the future for multimodal bio-imaging and targeted cancer therapy.

  12. Enhanced germanium precipitation and nanocrystal growth in the Ge+ ion-implanted SiO2 films during high-pressure annealing

    Science.gov (United States)

    Tyschenko, Ida E.; Volodin, Vladimir A.; Cherkov, Alexander G.

    2016-12-01

    The effect of pressure employed during subsequent annealing of the Ge+-ion implanted SiO2 layers on the Ge nanocrystal formation was studied. Ge+ ions implanted in the thin SiO2 layers formed Gauss-like profiles with a Ge peak concentration varied from 1 to 12 at%. Subsequent annealing was carried out at temperature 600-1130 °C under pressures 1-1.2×104 bar. Strong effect of the pressure on the Ge atom distribution was obtained. High-temperature annealing under pressure within the range of 1-103 bar resulted in the out-diffusion of germanium from the SiO2 layer to the Si substrate. As the pressure reached 1.2×104 bar, Ge migration to the Si/SiO2 interface was prevented. At that, the Ge nanocrystal growth within the ion-implanted region of the SiO2 film took place. The nanocrystal size was investigated as a function both of the Ge atom concentration and the annealing temperature. The obtained results show a diffusion-controlled nanocrystal growth mechanism. The high-pressure (1.2×104 bar) diffusion coefficient of germanium in silicon dioxide was estimated as a function of the temperature and expressed by D=1.1×10-10 exp(-1.43 eV/kT) cm2/s.

  13. Evidence of Silicon Band-Edge Emission Enhancement When Interfaced with SiO2:Er Films

    Science.gov (United States)

    Abedrabbo, S.; Fiory, A. T.; Ravindra, N. M.

    2017-02-01

    Nearly two-orders of magnitude increase in room-temperature band-to-band (1.067 eV) infrared emission from crystalline silicon, coated with erbium-doped sol-gel films, have been achieved. Phonon-assisted band-to-band emission from coated and annealed p-Si is strongest for the sample annealed at 700°C. In this paper, evidence of the origin of the emission band from the band edge recombination activities is established. Enhancement of radiative recombination of free carriers is reasoned by stresses at the interface due to the annealed sol-gel-deposited silica. Comparative studies with other strained silicon samples are presented.

  14. Growth of rutile TiO2 nanorods in Ti and Cu ion sequentially implanted SiO2 and the involved mechanisms

    Science.gov (United States)

    Mu, Xiaoyu; Liu, Xiaoyu; Wang, Xiaohu; Dai, Haitao; Liu, Changlong

    2018-01-01

    TiO2 in nanoscale exhibits unique physicochemical and optoelectronic properties and has attracted much more interest of the researchers. In this work, TiO2 nanostructures are synthesized in amorphous SiO2 slices by implanting Ti ions, or sequentially implanting Ti and Cu ions combined with annealing at high temperature. The morphology, structure, spatial distribution and optical properties of the formed nanostructures have been investigated in detail. Our results clearly show that the thermal growth of TiO2 nanostructures in SiO2 substrate is significantly enhanced by presence of post Cu ion implantation, which depends strongly on the applied Cu ion fluence, as well as the annealing atmosphere. Due to the formation of Cu2O in the substrate, rutile TiO2 nanorods of large size have been well fabricated in the Ti and Cu sequentially implanted SiO2 after annealing in N2 atmosphere, in which Cu2O plays a role as a catalyst. Moreover, the sample with well-fabricated TiO2 nanorods exhibits a narrowed band gap, an enhanced optical absorption in visible region, and catalase-/peroxidase-like catalytic characteristics. Our findings provide an effective route to fabricate functional TiO2 nanorods in SiO2 via ion implantation.

  15. High-Efficiency Si Solar Cell Fabricated by Ion Implantation and Inline Backside Rounding Process

    Directory of Open Access Journals (Sweden)

    Chien-Ming Lee

    2012-01-01

    Full Text Available We introduce a novel, high-throughput processing method to produce high-efficiency solar cells via a backside rounding process and ion implantation. Ion implantation combined with a backside rounding process is investigated. The ion implantation process substituted for thermal POCl3 diffusion performs better uniformity (<3%. The U-4100 spectrophotometer shows that wafers with backside rounding process perform higher reflectivity at long wavelengths. Industrial screen printed (SP Al-BSF on different etching depth groups was analyzed. SEMs show that increasing etch depth improves back surface field (BSF. The - measurement revealed that etching depths of 6 μm ± 0.1 μm due to having the highest and , it has the best performance. SEMs also show that higher etching depths also produce uniform Al melting and better BSF. This is in agreement with IQE response data at long wavelengths.

  16. Mechanism of leakage of ion-implantation isolated AlGaN/GaN MIS-high electron mobility transistors on Si substrate

    Science.gov (United States)

    Zhang, Zhili; Song, Liang; Li, Weiyi; Fu, Kai; Yu, Guohao; Zhang, Xiaodong; Fan, Yaming; Deng, Xuguang; Li, Shuiming; Sun, Shichuang; Li, Xiajun; Yuan, Jie; Sun, Qian; Dong, Zhihua; Cai, Yong; Zhang, Baoshun

    2017-08-01

    In this paper, we systematically investigated the leakage mechanism of the ion-implantation isolated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) on Si substrate. By means of combined DC tests at different temperatures and electric field dependence, we demonstrated the following original results: (1) It is proved that gate leakage is the main contribution to OFF-state leakage of ion-implantation isolated AlGaN/GaN MIS-HEMTs, and the gate leakage path is a series connection of the gate dielectric Si3N4 and Si3N4-GaN interface. (2) The dominant mechanisms of the leakage current through LPCVD-Si3N4 gate dielectric and Si3N4-GaN interface are identified to be Frenkel-Poole emission and two-dimensional variable range hopping (2D-VRH), respectively. (3) A certain temperature annealing could reduce the density of the interface state that produced by ion implantation, and consequently suppress the interface leakage transport, which results in a decrease in OFF-state leakage current of ion-implantation isolated AlGaN/GaN MIS-HEMTs.

  17. Semiconductor Plasmon Induced Up-Conversion Enhancement in mCu2-xS@SiO2@Y2O3:Yb3+/Er3+ Core-Shell Nanocomposites.

    Science.gov (United States)

    Zhou, Donglei; Li, Dongyu; Zhou, Xiangyu; Xu, Wen; Chen, Xu; Liu, Dali; Zhu, Yongsheng; Song, Hongwei

    2017-10-11

    The ability to modulate the intensity of electromagnetic field by semiconductor plasmon nanoparticles is becoming attractive due to its unique doping-induced local surface plasmon resonance (LSPR) effect that is different from metals. Herein, we synthesized mCu2-xS@SiO2@Y2O3:Yb3+/Er3+ core-shell composites and experimentally and theoretically studied the semiconductor plasmon induced up-conversion enhancement and obtained 30-fold up-conversion enhancement compared with that of SiO2@Y2O3:Yb3+/Er3+ composites. The up-conversion enhancement was induced by the synthetic effect: the amplification of the excitation field and the increase of resonance energy transfer (ET) rate from Yb3+ ions to Er3+ ions. The experimental results were analyzed in the light of finite-difference time-domain (FDTD) calculations, confirming the effect of the amplification of the excitation field. In addition, up-conversion luminescence (UCL) spectra, up-conversion enhancement, and dynamics dependent on concentration (Yb3+ and Er3+ ions) were investigated, and it was found that the resonance ET rate from Yb3+ ions to Er3+ ions increased ∼25% in the effect of LSPR waves. Finally, the power dependence of fingerprint identification was successfully performed based on the mCu2-xS@SiO2@Y2O3:Yb3+/Er3+ core-shell composites, the color of which can change from green to orange with excitation power increasing. Our work opens up a new concept to design and fabricate the up-conversion core-shell structure based on semiconductor plasmon nanoparticles (NPs) and provides applications for up-conversion nanocrystals (UCNPs) and semiconductor plasmon NPs in photonics.

  18. Co-delivery of siRNA and doxorubicin to cancer cells from additively manufactured implants

    DEFF Research Database (Denmark)

    Chen, Muwan; Andersen, Morten Østergaard; Dillschneider, Philipp

    2015-01-01

    Tumors in load bearing bone tissue are a major clinical problem, in part because surgical resection invokes a dilemma whether to resect aggressively, risking mechanical failure, or to resect conservatively, risking cancer recurrence due to residual malignant cells. A chemo-functionalized implant,...

  19. Magnetic properties and magnetocaloric effect in the RCu{sub 2}Si{sub 2} and RCu{sub 2}Ge{sub 2} (R = Ho, Er) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Zhao-Jun [School of Material Science and Engineering, Hebei University of Technology, Tianjin (China); Key laboratory of cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China); Shen, Jun, E-mail: jshen@mail.ipc.ac.cn, E-mail: tangcc@hebut.edu.cn; Wu, Jian-Feng [Key laboratory of cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China); Yan, Li-Qin; Wang, Li-Chen; Sun, Ji-rong; Shen, Bao-Gen [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter, Physics and Institute of Physics, Chinese Academy of Sciences, Beijing (China); Gao, Xin-Qiang; Tang, Cheng-Chun, E-mail: jshen@mail.ipc.ac.cn, E-mail: tangcc@hebut.edu.cn [School of Material Science and Engineering, Hebei University of Technology, Tianjin (China)

    2014-02-21

    The magnetic properties and magnetocaloric effect (MCE) in RCu{sub 2}Si{sub 2} and RCu{sub 2}Ge{sub 2} (R = Ho, Er) compounds have been investigated. All these compounds possess an antiferromagnetic (AFM)-paramagnetic (PM) transition around their respective Neel temperatures. The RCu{sub 2}Si{sub 2} compounds undergo spin-glassy behavior above Neel temperature. Furthermore, a field-induced metamagnetic transition from AFM to ferromagnetic (FM) states is observed in these compounds. The calculated magnetic entropy changes show that all RCu{sub 2}Si{sub 2} and RCu{sub 2}Ge{sub 2} (R = Ho, Er) compounds, especially, ErCu{sub 2}Si{sub 2} exhibits large MCEs with no thermal hysteresis and magnetic hysteresis loss. The value of −ΔS{sub M}{sup max} reaches 22.8 J/Kg K for magnetic field changes from 0 to 5 T. In particular, for field changes of 1 and 2 T, the giant reversible magnetic entropy changes −ΔS{sub M}{sup max} are 8.3 and 15.8 J/kg K at 2.5 K, which is lower than the boiling point of helium. The low-field giant magnetic entropy change, together with ignorable thermal hysteresis and field hysteresis loss of ErCu{sub 2}Si{sub 2} compound is expected to have effective applications in low temperature magnetic refrigeration.

  20. Fabrication and characterization of Er+3 doped SiO2/SnO2 glass-ceramic thin films for planar waveguide applications

    Science.gov (United States)

    Guddala, S.; Chiappini, A.; Armellini, C.; Turell, S.; Righini, G. C.; Ferrari, M.; Narayana Rao, D.

    2015-02-01

    Glass-ceramics are a kind of two-phase materials constituted by nanocrystals embedded in a glass matrix and the respective volume fractions of crystalline and amorphous phase determine the properties of the glass-ceramics. Among these properties transparency is crucial in particular when confined structures, such as, dielectric optical waveguides, are considered. Moreover, the segregation of dopant rare-earth ions, like erbium, in low phonon energy crystalline medium makes these structures more promising in the development of waveguide amplifiers. Here we are proposing a new class of low phonon energy tin oxide semiconductor medium doped silicate based planar waveguides. Er3+ doped (100-x) SiO2-xSnO2 (x= 10, 20, 25 and 30mol%), glass-ceramic planar waveguide thin films were fabricated by a simple sol-gel processing and dip coating technique. XRD and HRTEM studies indicates the glass-ceramic phase of the film and the dispersion of ~4nm diameter of tin oxide nanocrystals in the amorphous phase of silica. The spectroscopic assessment indicates the distribution of the dopant erbium ions in the crystalline medium of tin oxide. The observed low losses, 0.5±0.2 dB/cm, at 1.54 μm communication wavelength makes them a quite promising material for the development of high gain integrated optical amplifiers.

  1. Depth profile investigation of β-FeSi{sub 2} formed in Si(1 0 0) by high fluence implantation of 50 keV Fe ion and post-thermal vacuum annealing

    Energy Technology Data Exchange (ETDEWEB)

    Lakshantha, Wickramaarachchige J.; Kummari, Venkata C.; Reinert, Tilo; McDaniel, Floyd D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Rout, Bibhudutta, E-mail: bibhu@unt.edu [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Center for Advanced Research and Technology, University of North Texas, 3940 North Elm Street, Denton, TX 76207 (United States)

    2014-08-01

    A single phase polycrystalline β-FeSi{sub 2} layer has been synthesized at the near surface region by implantation in Si(1 0 0) of a high fluence (∼10{sup 17} atoms/cm{sup 2}) of 50 keV Fe ions and subsequent thermal annealing in vacuum at 800 °C. The depth profile of the implanted Fe atoms in Si(1 0 0) were simulated by the widely used transportation of ions in matter (TRIM) computer code as well as by the dynamic transportation of ions in matter code (T-DYN). The simulated depth profile predictions for this heavy ion implantation process were experimentally verified using Rutherford Backscattering Spectrometry (RBS) and X-ray Photoelectron Spectroscopy (XPS) in combination with Ar-ion etching. The formation of the β-FeSi{sub 2} phase was monitored by X-ray diffraction measurements. The T-DYN simulations show better agreement with the experimental Fe depth profile results than the static TRIM simulations. The experimental and T-DYN simulated results show an asymmetric distribution of Fe concentrated more toward the surface region of the Si substrate.

  2. Study of the changes in the infrared transmission of SiO sub 2 spin-on-glass due to ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Shacham-Diamand, Y. (School of Electrical Engineering and the National Nanofabrication Facility, Cornell University, Ithaca, New York (USA)); Finkman, E.; Pinkas, Y. (Electrical Engineering Department, Technion, Haifa 32000 (Israel)); Moriya, N. (Solid State Institute and Physics Department, Technion, Haifa 32000 (Israel))

    1991-12-02

    The ion implantation of phosphorus into spin-on-glass (SOG) SiO{sub 2} thin-film films modified the infrared transmission spectrum of the films. Two SOG types, polysiloxane and silicate, were ion implanted with doses in the 1{times}10{sup 14}--1{times}10{sup 15} cm{sup {minus}2} range and an energy of 40 keV. The Fourier-transform infrared spectrum of such films on silicon substrates was measured and the results are presented as a function of the implanted dose. The effect of the ion implantation on the silicate SOG was minute while significant changes were observed in the polysiloxane SOG. The major absorption peaks in the transmission spectrum were numerically analyzed and fitted to a set of Lorentzian functions. The peak heights, width, and area were measured. The ion implantation reduces the number of CH{sub 3} groups while the location of the Si-O absorption peak is shifted towards a shorter wavelength, i.e., a denser material. A physical interpretation of the absorption peak dependence on the ion-implanted dose is presented.

  3. Promising Ta-Ti-Zr-Si metallic glass coating without cytotoxic elements for bio-implant applications

    Science.gov (United States)

    Lai, J. J.; Lin, Y. S.; Chang, C. H.; Wei, T. Y.; Huang, J. C.; Liao, Z. X.; Lin, C. H.; Chen, C. H.

    2018-01-01

    Tantalum (Ta) is considered as one of the most promising metal due to its high corrosion resistance, excellent biocompatibility and cell adhesion/in-growth capabilities. Although there are some researches exploring the biomedical aspects of Ta and Ta based alloys, systematic characterizations of newly developed Ta-based metallic glasses in bio-implant applications is still lacking. This study employs sputtering approach to produced thin-film Ti-based metallic glasses due to the high melting temperature of Ta (3020 °C). Two fully amorphous Ta-based metallic glasses composed of Ta57Ti17Zr15Si11 and Ta75Ti10Zr8Si7 are produced and experimentally characterized in terms of their mechanical properties, bio-corrosion properties, surface hydrophilic characteristics, and in-vitro cell viability and cells attachment tests. Compare to conventional pure Ti and Ta metals, the developed Ta-based metallic glasses exhibit higher hardness and lower modulus which are better match to the mechanical properties of bone. MTS assay results show that Ta-based metallic glasses show comparable cell viability and cell attachment rate compared to that of pure Ti and Ta surface in a 72 h in-vitro test.

  4. Leaky mode suppression in planar optical waveguides written in Er:TeO{sub 2}–WO{sub 3} glass and CaF{sub 2} crystal via double energy implantation with MeV N{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Bányász, I., E-mail: banyasz@sunserv.kfki.hu [Department of Crystal Physics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O.B. 49, H-1525 Budapest (Hungary); Zolnai, Z.; Fried, M. [Research Institute for Technical Physics and Materials Science, Research Centre for Natural Sciences, Hungarian Academy of Sciences, P.O.B. 49, Budapest H-1525 (Hungary); Berneschi, S. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); “Enrico Fermi” Center for Study and Research, Piazza del Viminale 2, 00184 Roma (Italy); Pelli, S.; Nunzi-Conti, G. [MDF-Lab, “Nello Carrara” Institute of Applied Physics, IFAC-CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2014-05-01

    Ion implantation proved to be an universal technique for producing waveguides in most optical materials. Tellurite glasses are good hosts of rare-earth elements for the development of fibre and integrated optical amplifiers and lasers covering all the main telecommunication bands. Er{sup 3+}-doped tellurite glasses are good candidates for the fabrication of broadband amplifiers in wavelength division multiplexing around 1.55 μm, as they exhibit large stimulated cross sections and broad emission bandwidth. Calcium fluoride is an excellent optical material, due to its perfect optical characteristics from UV wavelengths up to near IR. It has become a promising laser host material (doped with rare earth elements). Ion implantation was also applied to optical waveguide fabrication in CaF{sub 2} and other halide crystals. In the present work first single-energy implantations at 3.5 MeV at various fluences were applied. Waveguide operation up to 1.5 μm was observed in Er:Te glass, and up to 980 nm in CaF{sub 2}. Then double-energy implantations at a fixed upper energy of 3.5 MeV and lower energies between 2.5 and 3.2 MeV were performed to suppress leaky modes by increasing barrier width.

  5. Origin of the lattice sites occupied by implanted Co in Si

    CERN Document Server

    Silva, Daniel; Wahl, Ulrich; Martins Correia, Joao; Da Costa Pereira, Lino Miguel; Amorim, Lígia; Castro Ribeiro Da Silva, Manuel; Esteves De Araujo, Araujo Joao Pedro

    2014-01-01

    We have investigated the lattice location of implanted 61Co in silicon. By means of emission channeling, three different lattice sites have been identified: ideal substitutional sites, displaced bond-centered sites and displaced tetrahedral interstitial sites. To assess the origin of the observed lattice sites we have compared our results to emission channeling studies on 59Fe and 65Ni and to Mössbauer spectroscopy experiments on 57Co, present in literature. The possible interpretation of several 57Co Mössbauer lines is discussed in the light of our new results on the 61Co lattice location. The conclusions are relevant for the microscopic understanding of some gettering techniques.

  6. Room-temperature vacancy migration in crystalline Si from an ion-implanted surface layer

    DEFF Research Database (Denmark)

    Larsen, Arne Nylandsted; Christensen, Carsten; Petersen, Jon Wulff

    1999-01-01

    Migration of vacancies in crystalline, n-type silicon at room temperature from Ge+-implanted (150 keV, 5×109–1×1011 cm–2) surface layers was studied by tracing the presence of P–V pairs (E centers) in the underlying layer using deep level transient spectroscopy (DLTS). Under the conditions we have...... examined, the vacancies migrate to a maximum depth of about 1 µm and at least one vacancy per implanted Ge ion migrates into the silicon crystal. The annealing of the E centers is accompanied, in an almost one-to-one fashion, by the appearance of a new DLTS line corresponding to a level at EC......–Et[approximate]0.15 eV that has donor character. It is argued that the center associated with this line is most probably the P2–V complex; it anneals at about 550 K. A lower limit of the RT-diffusion coefficient of the doubly charged, negative vacancy is estimated to be 4×10–11 cm2/s. ©1999 American Institute...

  7. Change in equilibrium position of misfit dislocations at the GaN/sapphire interface by Si-ion implantation into sapphire—I. Microstructural characterization

    Directory of Open Access Journals (Sweden)

    Sung Bo Lee

    2015-07-01

    Full Text Available Much research has been done to reduce dislocation densities for the growth of GaN on sapphire, but has paid little attention to the elastic behavior at the GaN/sapphire interface. In this study, we have examined effects of the addition of Si to a sapphire substrate on its elastic property and on the growth of GaN deposit. Si atoms are added to a c-plane sapphire substrate by ion implantation. The ion implantation results in scratches on the surface, and concomitantly, inhomogeneous distribution of Si. The scratch regions contain a higher concentration of Si than other regions of the sapphire substrate surface, high-temperature GaN being poorly grown there. However, high-temperature GaN is normally grown in the other regions. The GaN overlayer in the normally-grown regions is observed to have a lower TD density than the deposit on the bare sapphire substrate (with no Si accommodated. As compared with the film on an untreated, bare sapphire, the cathodoluminescence defect density decreases by 60 % for the GaN layer normally deposited on the Si-ion implanted sapphire. As confirmed by a strain mapping technique by transmission electron microscopy (geometric phase analysis, the addition of Si in the normally deposited regions forms a surface layer in the sapphire elastically more compliant than the GaN overlayer. The results suggest that the layer can largely absorb the misfit strain at the interface, which produces the overlayer with a lower defect density. Our results highlight a direct correlation between threading-dislocation density in GaN deposits and the elastic behavior at the GaN/sapphire interface, opening up a new pathway to reduce threading-dislocation density in GaN deposits.

  8. Structural properties of the formation of zinc-containing nanoparticles obtained by ion implantation in Si (001 and subsequent thermal annealing

    Directory of Open Access Journals (Sweden)

    Ksenia B. Eidelman

    2017-09-01

    We show that a damaged layer with a large concentration of radiation induced defects forms near the surface as a result of the implantation of Zn+ ions with an energy of 50 keV. In the as-implanted state, nanoparticles of metallic Zn with a size of about 25 nm form at a depth of 40 nm inside the damaged silicon layer. Subsequent annealing at 800 °C in a dry oxygen atmosphere leads to structural changes in the defect layer and the formation of Zn2SiO4 nanoparticles at a depth of 25 nm with an average size of 3 nm, as well as oxidation of the existing Zn particles to the Zn2SiO4 phase. The oxidation of the metallic Zn nanoparticles starts from the surface of the particles and leads to the formation of particles with a “core-shell” structure. Analysis of the phase composition of the silicon layer after two-stage implantation with O+ and Zn+ ions showed that Zn and Zn2SiO4 particles form in the as-implanted state. Subsequent annealing at 800 °C in a dry oxygen atmosphere leads to an increase in the particle size but does not change the phase composition of the near-surface layer. ZnO nanoparticles were not observed under these experimental conditions of ion beam synthesis.

  9. Fe-implanted 6H-SiC: Direct evidence of Fe{sub 3}Si nanoparticles observed by atom probe tomography and {sup 57}Fe Mössbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Diallo, M. L.; Fnidiki, A., E-mail: abdeslem.fnidiki@univ-rouen.fr; Lardé, R.; Cuvilly, F.; Blum, I. [Groupe de Physique des Matériaux, Université et INSA de Rouen - UMR CNRS 6634 - Normandie Université. F-76801 Saint Etienne du Rouvray (France); Lechevallier, L. [Groupe de Physique des Matériaux, Université et INSA de Rouen - UMR CNRS 6634 - Normandie Université. F-76801 Saint Etienne du Rouvray (France); Département de GEII, Université de Cergy-Pontoise, rue d' Eragny, Neuville sur Oise, 95031 Cergy-Pontoise (France); Debelle, A.; Thomé, L. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), CNRS-IN2P3-Univ. Paris-Sud 11, Bât. 108, 91405 Orsay (France); Viret, M. [Service de Physique de l' Etat Condensé (DSM/IRAMIS/SPEC), UMR 3680 CNRS, Bât. 772, Orme des Merisiers, CEA Saclay 91191 Gif sur Yvette (France); Marteau, M.; Eyidi, D.; Declémy, A. [Institut PPRIME, UPR 3346 CNRS, Université de Poitiers, ENSMA, SP2MI, téléport 2, 11 Bvd M. et P. Curie 86962 Futuroscope, Chasseneuil (France)

    2015-05-14

    In order to understand ferromagnetic ordering in SiC-based diluted magnetic semiconductors, Fe-implanted 6H-SiC subsequently annealed was studied by Atom Probe Tomography, {sup 57}Fe Mössbauer spectroscopy and SQUID magnetometry. Thanks to its 3D imaging capabilities at the atomic scale, Atom Probe Tomography appears as the most suitable technique to investigate the Fe distribution in the 6H-SiC host semiconductor and to evidence secondary phases. This study definitely evidences the formation of Fe{sub 3}Si nano-sized clusters after annealing. These clusters are unambiguously responsible for the main part of the magnetic properties observed in the annealed samples.

  10. NIR luminescent Er{sup 3+}/Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} nanostructured planar and channel waveguides: Optical and structural properties

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Cesar dos Santos [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Ferrari, Jefferson Luis [Grupo de Pesquisa em Quimica de Materiais - (GPQM), Departamento de Ciencias Naturais, Universidade Federal de Sao Joao Del Rei, Campus Dom Bosco, Praca Dom Helvecio, 74, 36301-160, Sao Joao Del Rei, MG (Brazil); Oliveira, Drielly Cristina de [Departamento de Quimica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirao Preto/SP (Brazil); Maia, Lauro June Queiroz [Grupo Fisica de Materiais, Instituto de Fisica, UFG, Campus Samambaia, Caixa Postal 131, 74001-970, Goiania/GO (Brazil); Gomes, Anderson Stevens Leonidas [Departamento de Fisica, Universidade Federal de Pernambuco, Cidade Universitaria, Recife/PE, 50670-901 (Brazil); Ribeiro, Sidney Jose Lima [Laboratorio de Materiais Fotonicos, Instituto de Quimica, UNESP, Caixa Postal 355, 14801-970, Araraquara/SP (Brazil); and others

    2012-09-14

    Optical and structural properties of planar and channel waveguides based on sol-gel Er{sup 3+} and Yb{sup 3+} co-doped SiO{sub 2}-ZrO{sub 2} are reported. Microstructured channels with high homogeneous surface profile were written onto the surface of multilayered densified films deposited on SiO{sub 2}/Si substrates by a femtosecond laser etching technique. The densification of the planar waveguides was evaluated from changes in the refractive index and thickness, with full densification being achieved at 900 Degree-Sign C after annealing from 23 up to 500 min, depending on the ZrO{sub 2} content. Crystal nucleation and growth took place together with densification, thereby producing transparent glass ceramic planar waveguides containing rare earth-doped ZrO{sub 2} nanocrystals dispersed in a silica-based glassy host. Low roughness and crack-free surface as well as high confinement coefficient were achieved for all the compositions. Enhanced NIR luminescence of the Er{sup 3+} ions was observed for the Yb{sup 3+}-codoped planar waveguides, denoting an efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Highlights: Black-Right-Pointing-Pointer Sol-gel high NIR luminescent nanostructured planar and channel waveguides. Black-Right-Pointing-Pointer Microstructured channels written by a femtosecond laser etching technique. Black-Right-Pointing-Pointer Transparent glass ceramic with rare earth-doped ZrO{sub 2} nanocrystals in a silica host. Black-Right-Pointing-Pointer Enhanced NIR luminescence, efficient energy transfer from the Yb{sup 3+} to the Er{sup 3+} ion. Black-Right-Pointing-Pointer New planar channel waveguides to be applied as EDWA in the C telecommunication band.

  11. Change in equilibrium position of misfit dislocations at the GaN/sapphire interface by Si-ion implantation into sapphire. II. Electron energy loss spectroscopic study

    Directory of Open Access Journals (Sweden)

    Sung Bo Lee

    2015-07-01

    Full Text Available In Part I, we have shown that the addition of Si into sapphire by ion implantationmakes the sapphire substrate elastically softer than for the undoped sapphire. The more compliant layer of the Si-implanted sapphire substrate can absorb the misfit stress at the GaN/sapphire interface, which produces a lower threading-dislocation density in the GaN overlayer. Here in Part II, based on experimental results by electron energy loss spectroscopy and a first-principle molecular orbital calculation in the literature, we suggest that the softening effect of Si results from a reduction of ionic bonding strength in sapphire (α-Al2O3 with the substitution of Si for Al.

  12. Growth of WSi2 in phosphorous-implanted W/«Si» couples

    Science.gov (United States)

    Ma, E.; Lim, B. S.; Nicolet, M.-A.; Alvi, N. S.; Hamdi, A. H.

    1988-05-01

    The thermal reaction of rf-sputter-deposited tungsten films with a (100) silicon substrate is investigated by vacuum furnace annealing and rapid thermal annealing. An irradiation of the W/Si interface by a phosphorous ion beam at room temperature prior to annealing promotes a uniform interfacial growth of WSi2. The growth of WSi2 follows diffusion-controlled kinetics during both furnace annealing and rapid thermal processing. A growth law of x2 = kt is obtained for furnace annealing between 690 and 740° C, where x is the thickness of the compound, t is the annealing duration after an initial incubation period and k = 62 (cm2/s) exp (--3.0 eV/kT). The surface smoothness of the suicide films improves with increasing ion dose.

  13. Synthesis of nano-patterned and Nickel Silicide embedded amorphous Si thin layer by ion implantation for higher efficiency solar devices

    Science.gov (United States)

    Bhowmik, D.; Bhattacharjee, S.; Lavanyakumar, D.; Naik, V.; Satpati, B.; Karmakar, P.

    2017-11-01

    We report the ion beam based single step synthesis process of surface-patterned amorphous Silicon (a-Si) with a buried plasmon active nickel silicide layer for the realization of cost-effective, higher efficiency Silicon (Si) photovoltaic devices. Simultaneous amorphization, surface pattern formation and buried layer development are achieved by normal incidence 10 keV Ni1+ ion bombardment on Si(100) surface at a fluence of 1 × 1017. Atomic Force Microscopy study shows rim-surrounded crater like periodic nanostructure on the surface whereas cross-sectional Transmission Electron Microscopy detects the amorphization and implant buried layer just below the surface. The distribution of implanted Ni ions and Si vacancies, obtained by the Monte Carlo simulation (SRIM) is consistent with the experimental results. Spatially resolved Electron Energy Loss Spectroscopy measurement detects that the buried layer is nickel silicide. The potential application of such nano-patterned and plasmon active system for future low-cost a-Si based higher efficient Photovoltaic devices is discussed.

  14. In vivo study of nanostructured diopside (CaMgSi{sub 2}O{sub 6}) coating on magnesium alloy as biodegradable orthopedic implants

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, Mehdi, E-mail: mrzavi2659@gmail.com [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Savabi, Omid [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Razavi, Seyed Mohammad [School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Heidari, Fariba; Manshaei, Maziar [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Vashaee, Daryoosh [School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Tayebi, Lobat, E-mail: lobat.tayebi@okstate.edu [School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078 (United States)

    2014-09-15

    Highlights: • In vitro biocompatibility of biodegradable Mg alloy was improved by diopside coating. • In vivo biocompatibility of biodegradable Mg alloy was improved by diopside coating. • Degradation behavior of biodegradable Mg alloy was improved by diopside coating. - Abstract: In order to improve the corrosion resistance and bioactivity of a biodegradable magnesium alloy, we have recently prepared a nanostructured diopside (CaMgSi{sub 2}O{sub 6}) coating on AZ91 magnesium alloy through a combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) method (reported elsewhere). In this work, we performed a detailed biocompatibility analysis of the implants made by this material and compared their performance with those of the uncoated and micro arc oxidized magnesium implants. The biocompatibility evaluation of samples was performed by culturing L-929 cells and in vivo animal study, including implantation of samples in greater trochanter of rabbits, radiography and histological examinations. The results from both the in vitro and in vivo studies indicated that the diopside/MAO coated magnesium implant significantly enhanced cell viability, biodegradation resistance and new bone formation compared with both the uncoated and the micro-arc oxidized magnesium implants. Our data provides an example of how the proper surface treatment of magnesium implants can overcome their drawbacks in terms of high degradation rate and gas bubble formation under physiological conditions.

  15. Fabrication of 4H-SiC lateral double implanted MOSFET on an on-axis semi-insulating substrate without using epi-layer

    Science.gov (United States)

    Kim, Hyoung Woo; Seok, Ogyun; Moon, Jeong Hyun; Bahng, Wook; Jo, Jungyol

    2017-12-01

    4H-SiC lateral double implanted metal–oxide–semiconductor field effect transistors (LDIMOSFET) were fabricated on on-axis semi-insulating SiC substrates without using an epi-layer. The LDIMOSFET adopted a current path layer (CPL), which was formed by ion-implantation. The CPL works as a drift region between gate and drain. By using on-axis semi-insulating substrate and optimized CPL parameters, breakdown voltage (BV) of 1093 V and specific on-resistance (R on,sp) of 89.8 mΩ·cm2 were obtained in devices with 20 µm long CPL. Experimentally extracted field-effect channel mobility was 21.7 cm2·V‑1·s‑1 and the figure-of-merit (BV2/R on,sp) was 13.3 MW/cm2.

  16. Coating of biodegradable magnesium alloy bone implants using nanostructured diopside (CaMgSi{sub 2}O{sub 6})

    Energy Technology Data Exchange (ETDEWEB)

    Razavi, Mehdi, E-mail: mehdi.razavi@okstate.edu [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Department of Anatomical Sciences and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); School of Materials Science and Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); Fathi, Mohammadhossein [Biomaterials Research Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Dental Materials Research Center, Isfahan University of Medical Sciences, Isfahan (Iran, Islamic Republic of); Savabi, Omid [Torabinejad Dental Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Beni, Batoul Hashemi [Department of Anatomical Sciences and Molecular Biology, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Razavi, Seyed Mohammad [School of Dentistry, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Vashaee, Daryoosh [School of Electrical and Computer Engineering, Helmerich Advanced Technology Research Center, Oklahoma State University, Tulsa, OK 74106 (United States); and others

    2014-01-01

    Magnesium alloys with their biodegradable characteristic can be a very good candidate to be used in orthopedic implants. However, magnesium alloys may corrode and degrade too fast for applications in the bone healing procedure. In order to enhance the corrosion resistance and the in vitro bioactivity of a magnesium alloy, a nanostructured diopside (CaMgSi{sub 2}O{sub 6}) film was coated on AZ91 magnesium alloy through combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) methods. The crystalline structures, morphologies and compositions of the coated and uncoated substrates were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy. Polarization, electrochemical impedance spectroscopy, and immersion test in simulated body fluid (SBF) were employed to evaluate the corrosion resistance and the in vitro bioactivity of the samples. The results of our investigation showed that the nanostructured diopside coating deposited on the MAO layer increases the corrosion resistance and improves the in vitro bioactivity of the biodegradable magnesium alloy.

  17. TEM investigation of the surface layer structure [111]{sub B2} of the single NiTi crystal modified by the Si-ion beam implantation

    Energy Technology Data Exchange (ETDEWEB)

    Girsova, S. L., E-mail: girs@ispms.tsc.ru; Poletika, T. M., E-mail: poletm@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); Meisner, S. N., E-mail: msn@ispms.tsc.ru; Meisner, L. L., E-mail: llm@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation); National Research Tomsk State University, Tomsk, 634050 (Russian Federation)

    2015-10-27

    The study was carried on for the single NiTi crystals subjected to the Si-ion beam implantation. Using the transmission electron microscopy technique (TEM), the surface layer structure [111]{sub B2} was examined for the treated material. The modified near-surface sublayers were found to have different composition. Thus the uppermost sublayer contained mostly oxides; the lower-lying modified sublayer material was in an amorphous state and the thin underlying sublayer had a defect structure.

  18. Moessbauer-spectroscopic study of structure and magnetism of the exchange-coupled layer systems Fe/FeSn{sub 2}, and Fe/FeSi/Si and the ion-implanted diluted magnetic semiconductor SiC(Fe); Moessbauerspektroskopische Untersuchung von Struktur und Magnetismus der austauschgekoppelten Schichtsysteme Fe/FeSn{sub 2} und Fe/FeSi/Si und des ionenimplantierten verduennten magnetischen Halbleiters SiC(Fe)

    Energy Technology Data Exchange (ETDEWEB)

    Stromberg, Frank

    2009-07-07

    In line with this work the structural and magnetic properties of the exchange coupled layered systems Fe/FeSn{sub 2} and Fe/FeSi/Si and of the Fe ion implanted diluted magnetic semiconductor (DMS) SiC(Fe) were investigated. The main measuring method was the isotope selective {sup 57}Fe conversion electron Moessbauer spectroscopy (CEMS), mostly in connection with the {sup 57}Fe tracer layer technique, in a temperature range from 4.2 K to 340 K. Further measurement techniques were X-ray diffraction (XRD), electron diffraction (LEED, RHEED), SQUID magnetometry and FMR (Ferromagnetic Resonance). In the first part of this work the properties of thin AF FeSn{sub 2}(001) films and of the exchange-bias system Fe/FeSn{sub 2}(001) on InSb(001) were investigated. With the application of {sup 57}Fe-tracer layers and CEMS both the Fe-spin structure and the temperature dependence of the magnetic hyperfine field (B{sub hf}) of FeSn{sub 2} could be examined. The evaporation of Fe films on the FeSn{sub 2} films produced in the latter ones a high perpendicular spin component at the Fe/FeSn{sub 2} interface. In some distance from the interface the Fe spins rotate back into the sample plane. Furthermore {sup 57}Fe-CEMS provided a correlation between the absolute value of the exchange field vertical stroke He vertical stroke and the amount of magnetic defects within the FeSn{sub 2}. Temperature dependent CEMS-measurements yielded informations about the spin dynamics within the AF. The transition temperatures T{sub B}{sup *}, which were interpreted as superparamagnetic blocking temperatures, obtain higher values compared to the temperatures T{sub B} of the exchange-bias effect, obtained with magnetometry measurements. The second part of this work deals with the indirect exchange coupling within Fe/FeSi/Si/FeSi/Fe multilayers and FeSi diffusion barriers. The goal was to achieve Fe free Si interlayers. The CEMS results show that starting from a thickness of t{sub FeSi}=10-12 A of the

  19. Characterization of Defects in N-type 4H-SiC After High-Energy N Ion Implantation by RBS-Channeling and Raman Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kummari, Venkata C.; Reinert, Tilo; Jiang, Weilin; McDaniel, Floyd D.; Rout, Bibhudutta

    2014-08-01

    Implantation with 1 MeV N ions was performed at room temperature in n-type 4H-SiC(0001) to four implantation fluences (or doses in dpa (displacements per atom) at the damage peak) of 1.5×1013(0.0034), 7.8×1013(0.018), 1.5×1014(0.034), and 7.8×1014(0.18) ions/cm2, respectively. The evolution of disorder was studied using Rutherford backscattering spectrometry in channeling mode (RBS-C) and Raman spectroscopy. The disorder in the Si sub-lattice was found to be less than 10% for the dpa of 0.0034 and 0.0178 and increased to 40% and 60% for the dpa of 0.034 and 0.178 respectively. Raman Spectroscopy was performed using a green laser of wavelength 532 nm as excitation source. The normalized Raman Intensity, In shows disorder of 41%, 69%, 77% and 100% for the dpa of 0.0034, 0.017, 0.034 and 0.178 respectively. In this paper, the characterizations of the defects produced due to the Nitrogen implantation in 4H-SiC are presented and the results are discussed.

  20. Characterization of defects in n-type 4H-SiC after high-energy N ion implantation by RBS-channeling and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kummari, Venkata C.; Reinert, Tilo [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Jiang, Weilin [Pacific Northwest National Laboratory, Richland, WA 99352 (United States); McDaniel, Floyd D. [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Rout, Bibhudutta, E-mail: bibhu@unt.edu [Ion Beam Modification and Analysis Laboratory, Department of Physics, University of North Texas, 1155 Union Circle #311427, Denton, TX 76203 (United States); Center for Advanced Research and Technology, University of North Texas, 3940 North Elm Street, Denton, TX 76207 (United States)

    2014-08-01

    Implantation with 1 MeV N ions was performed at room temperature in n-type 4H-SiC (0 0 0 1) at four implantation fluences (or doses in dpa (displacements per atom) at the damage peak) of 1.5 × 10{sup 13} (0.0034), 7.8 × 10{sup 13} (0.018), 1.5 × 10{sup 14} (0.034), and 7.8 × 10{sup 14} (0.178) ions/cm{sup 2}, respectively. The evolution of disorder was studied using Rutherford backscattering spectrometry in channeling mode (RBS-C), Raman spectroscopy, and optical transmission. The disorder in the Si sub-lattice was found to be less than 10% for the dpa of 0.0034 and 0.0178 and increased to 40% and 60% for the dpa of 0.034 and 0.178 respectively. The normalized Raman intensity I{sub n}, shows disorder of 41%, 69%, 77% and 100% for the dpa of 0.0034, 0.0178, 0.034 and 0.178, respectively. In this paper, the characterization of the defects produced due to the nitrogen implantation in 4H-SiC are presented and the results are discussed.

  1. Trap Depth Engineering of SrSi2O2N2:Ln2+,Ln3+(Ln2+= Yb, Eu; Ln3+= Dy, Ho, Er) Persistent Luminescence Materials for Information Storage Applications.

    Science.gov (United States)

    Zhuang, Yixi; Lv, Ying; Wang, Le; Chen, Wenwei; Zhou, Tian-Liang; Takeda, Takashi; Hirosaki, Naoto; Xie, Rong-Jun

    2018-01-17

    Deep-trap persistent luminescence materials exhibit unique properties of energy storage and controllable photon release under additional stimulation, allowing for both wavelength and intensity multiplexing to realize high-capacity storage in the next-generation information storage system. However, the lack of suitable persistent luminescence materials with deep traps is the bottleneck of such storage technologies. In this study, we successfully developed a series of novel deep-trap persistent luminescence materials in the Ln 2+ /Ln 3+ -doped SrSi 2 O 2 N 2 system (Ln 2+ = Yb, Eu; Ln 3+ = Dy, Ho, Er) by applying the strategy of trap depth engineering. Interestingly, the trap depth can be tailored by selecting different codopants, and it monotonically increases from 0.90 to 1.18 eV in the order of Er, Ho, and Dy. This is well explained by the energy levels indicated in the host-referred binding energy scheme. The orange-red-emitting SrSi 2 O 2 N 2 :Yb,Dy and green-emitting SrSi 2 O 2 N 2 :Eu,Dy phosphors are demonstrated to be good candidates of information storage materials, which are attributed to their deep traps, narrow thermoluminescence glow bands, high emission efficiency, and excellent chemical stability. This work not only validates the suitability of deep-trap persistent luminescence materials in the information storage applications, but also broadens the avenue to explore such kinds of new materials for applications in anticounterfeiting and advanced displays.

  2. Targeted siRNA Screens Identify ER-to-Mitochondrial Calcium Exchange in Autophagy and Mitophagy Responses in RPE1 Cells

    Directory of Open Access Journals (Sweden)

    Thomas D. B. MacVicar

    2015-06-01

    Full Text Available Autophagy is an important stress response pathway responsible for the removal and recycling of damaged or redundant cytosolic constituents. Mitochondrial damage triggers selective mitochondrial autophagy (mitophagy, mediated by a variety of response factors including the Pink1/Parkin system. Using human retinal pigment epithelial cells stably expressing autophagy and mitophagy reporters, we have conducted parallel screens of regulators of endoplasmic reticulum (ER and mitochondrial morphology and function contributing to starvation-induced autophagy and damage-induced mitophagy. These screens identified the ER chaperone and Ca2+ flux modulator, sigma non-opioid intracellular receptor 1 (SIGMAR1, as a regulator of autophagosome expansion during starvation. Screens also identified phosphatidyl ethanolamine methyl transferase (PEMT and the IP3-receptors (IP3Rs as mediators of Parkin-induced mitophagy. Further experiments suggested that IP3R-mediated transfer of Ca2+ from the ER lumen to the mitochondrial matrix via the mitochondrial Ca2+ uniporter (MCU primes mitochondria for mitophagy. Importantly, recruitment of Parkin to damaged mitochondria did not require IP3R-mediated ER-to-mitochondrial Ca2+ transfer, but mitochondrial clustering downstream of Parkin recruitment was impaired, suggesting involvement of regulators of mitochondrial dynamics and/or transport. Our data suggest that Ca2+ flux between ER and mitochondria at presumed ER/mitochondrial contact sites is needed both for starvation-induced autophagy and for Parkin-mediated mitophagy, further highlighting the importance of inter-organellar communication for effective cellular homeostasis.

  3. Targeted siRNA Screens Identify ER-to-Mitochondrial Calcium Exchange in Autophagy and Mitophagy Responses in RPE1 Cells.

    Science.gov (United States)

    MacVicar, Thomas D B; Mannack, Lilith V J C; Lees, Robert M; Lane, Jon D

    2015-06-11

    Autophagy is an important stress response pathway responsible for the removal and recycling of damaged or redundant cytosolic constituents. Mitochondrial damage triggers selective mitochondrial autophagy (mitophagy), mediated by a variety of response factors including the Pink1/Parkin system. Using human retinal pigment epithelial cells stably expressing autophagy and mitophagy reporters, we have conducted parallel screens of regulators of endoplasmic reticulum (ER) and mitochondrial morphology and function contributing to starvation-induced autophagy and damage-induced mitophagy. These screens identified the ER chaperone and Ca2+ flux modulator, sigma non-opioid intracellular receptor 1 (SIGMAR1), as a regulator of autophagosome expansion during starvation. Screens also identified phosphatidyl ethanolamine methyl transferase (PEMT) and the IP3-receptors (IP3Rs) as mediators of Parkin-induced mitophagy. Further experiments suggested that IP3R-mediated transfer of Ca2+ from the ER lumen to the mitochondrial matrix via the mitochondrial Ca2+ uniporter (MCU) primes mitochondria for mitophagy. Importantly, recruitment of Parkin to damaged mitochondria did not require IP3R-mediated ER-to-mitochondrial Ca2+ transfer, but mitochondrial clustering downstream of Parkin recruitment was impaired, suggesting involvement of regulators of mitochondrial dynamics and/or transport. Our data suggest that Ca2+ flux between ER and mitochondria at presumed ER/mitochondrial contact sites is needed both for starvation-induced autophagy and for Parkin-mediated mitophagy, further highlighting the importance of inter-organellar communication for effective cellular homeostasis.

  4. Spectroscopy features of Pr{sup 3+} and Er{sup 3+} ions in Li{sub 2}O-ZrO{sub 2}-SiO{sub 2} glass matrices mixed with some sesquioxides

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasa Rao, Ch. [Department of Physics, Acharya Nagarjuna University - Nuzvid Campus, Nuzvid-521201, A.P. (India); Kityk, I.V., E-mail: iwank74@gmail.com [Electrical Engineering Department, Technical University of Czestochowa, Aleja Armii, Krajowej 17/19, PL-42-201 Czestochowa (Poland); Srikumar, T.; Naga Raju, G.; Ravi Kumar, V.; Gandhi, Y.; Veeraiah, N. [Department of Physics, Acharya Nagarjuna University - Nuzvid Campus, Nuzvid-521201, A.P. (India)

    2011-09-15

    Highlights: > Optical spectra of Pr{sup 3+} and Er{sup 3+} ions in Li{sub 2}O-ZrO{sub 2}-SiO{sub 2}: Pr{sub 2}O{sub 3}/Er{sub 2}O{sub 3} with sesquioxides (viz., Al{sub 2}O{sub 3}, Sc{sub 2}O{sub 3}, Y{sub 2}O{sub 3}) studied. > The highest branching ratios {beta}{sub r} and quantum efficiencies of {sup 3}P{sub 0} {yields} {sup 3}H{sub 4} (Pr{sup 3+}) and {sup 4}S{sub 3/2} {yields} {sup 4}I{sub 15/2} (Er{sup 3+}) emissions have shown principal role of Y{sub 2}O{sub 3}. > Principal role of disorder around rare earth is established. - Abstract: The glasses of the composition Li{sub 2}O-ZrO{sub 2}-SiO{sub 2}: Pr{sub 2}O{sub 3}/Er{sub 2}O{sub 3} mixed with three interesting sesquioxides (viz., Al{sub 2}O{sub 3}, Sc{sub 2}O{sub 3}, Y{sub 2}O{sub 3}) were synthesized. Optical absorption and fluorescence spectra (in the spectral range 350-2100 nm were studied at ambient temperature. The Judd-Ofelt theory was applied to characterize the absorption and luminescence spectra of Pr{sup 3+} and Er{sup 3+} ions in these glasses. Following the luminescence spectra, various radiative properties like transition probability A, branching ratio {beta} and the radiative life time {tau} for different emission levels of two rare earth ions have been evaluated. The radiative life times for the upper levels {sup 3}P{sub 0} (Pr{sup 3+}) and {sup 4}S{sub 3/2} (Er{sup 3+}) have also been measured and quantum efficiencies were estimated. The variations observed in these parameters were discussed in the light of changing environment of rare earth ions due to mixing of different sesquioxides in the glass network.

  5. Y2O3:Yb,Er@mSiO2-CuxS double-shelled hollow spheres for enhanced chemo-/photothermal anti-cancer therapy and dual-modal imaging

    Science.gov (United States)

    Yang, Dan; Yang, Guixin; Wang, Xingmei; Lv, Ruichan; Gai, Shili; He, Fei; Gulzar, Arif; Yang, Piaoping

    2015-07-01

    Multifunctional composites have gained significant interest due to their unique properties which show potential in biological imaging and therapeutics. However, the design of an efficient combination of multiple diagnostic and therapeutic modes is still a challenge. In this contribution, Y2O3:Yb,Er@mSiO2 double-shelled hollow spheres (DSHSs) with up-conversion fluorescence have been successfully prepared through a facile integrated sacrifice template method, followed by a calcination process. It is found that the double-shelled structure with large specific surface area and uniform shape is composed of an inner shell of luminescent Y2O3:Yb,Er and an outer mesoporous silica shell. Ultra small CuxS nanoparticles (about 2.5 nm) served as photothermal agents, and a chemotherapeutic agent (doxorubicin, DOX) was then attached onto the surface of mesoporous silica, forming a DOX-DSHS-CuxS composite. The composite exhibits high anti-cancer efficacy due to the synergistic photothermal therapy (PTT) induced by the attached CuxS nanoparticles and the enhanced chemotherapy promoted by the heat from the CuxS-based PTT when irradiated by 980 nm near-infrared (NIR) light. Moreover, the composite shows excellent in vitro and in vivo X-ray computed tomography (CT) and up-conversion fluorescence (UCL) imaging properties owing to the doped rare earth ions, thus making it possible to achieve the target of imaging-guided synergistic therapy.Multifunctional composites have gained significant interest due to their unique properties which show potential in biological imaging and therapeutics. However, the design of an efficient combination of multiple diagnostic and therapeutic modes is still a challenge. In this contribution, Y2O3:Yb,Er@mSiO2 double-shelled hollow spheres (DSHSs) with up-conversion fluorescence have been successfully prepared through a facile integrated sacrifice template method, followed by a calcination process. It is found that the double-shelled structure with large

  6. 1.54  μm photoluminescence from Er:Ox centers at extremely low concentration in silicon at 300 K.

    Science.gov (United States)

    Celebrano, Michele; Ghirardini, Lavinia; Finazzi, Marco; Shimizu, Yasuo; Tu, Yuan; Inoue, Koji; Nagai, Yasuyoshi; Shinada, Takahiro; Chiba, Yuki; Abdelghafar, Ayman; Yano, Maasa; Tanii, Takashi; Prati, Enrico

    2017-09-01

    The demand for single photon emitters at λ=1.54  μm, which follows from the consistent development of quantum networks based on optical fiber technologies, makes Er:Ox centers in Si a viable resource, thanks to the I13/24→I415/2 optical transition of Er(3+). While its implementation in high-power applications is hindered by the extremely low emission rate, the study of such systems in the low concentration regime remains relevant for quantum technologies. In this Letter, we explore the room-temperature photoluminescence at the telecomm wavelength from very low implantation doses of Er:Ox in Si. The lower-bound number of optically active Er atoms detected is of the order of 10(2), corresponding to a higher-bound value for the emission rate per individual ion of about 10(4)  s(-1).

  7. Elimination of carbon vacancies in 4H-SiC epi-layers by near-surface ion implantation: Influence of the ion species

    Energy Technology Data Exchange (ETDEWEB)

    Ayedh, H. M.; Svensson, B. G. [University of Oslo, Department of Physics/Center for Materials Science and Nanotechnology, P.O. Box 1048 Blindern, N-0316 Oslo (Norway); Hallén, A. [School of Information and Communication Technology (ICT), Royal Institute of Technology, SE-164 40 Kista-Stockholm (Sweden)

    2015-11-07

    The carbon vacancy (V{sub C}) is a prevailing point defect in high-purity 4H-SiC epitaxial layers, and it plays a decisive role in controlling the charge carrier lifetime. One concept of reducing the V{sub C}-concentration is based on carbon self-ion implantation in a near surface layer followed by thermal annealing. This leads to injection of carbon interstitials (C{sub i}'s) and annihilation of V{sub C}'s in the epi-layer “bulk”. Here, we show that the excess of C atoms introduced by the self-ion implantation plays a negligible role in the V{sub C} annihilation. Actually, employing normalized implantation conditions with respect to displaced C atoms, other heavier ions like Al and Si are found to be more efficient in annihilating V{sub C}'s. Concentrations of V{sub C} below ∼2 × 10{sup 11} cm{sup −3} can be reached already after annealing at 1400 °C, as monitored by deep-level transient spectroscopy. This corresponds to a reduction in the V{sub C}-concentration by about a factor of 40 relative to the as-grown state of the epi-layers studied. The negligible role of the implanted species itself can be understood from simulation results showing that the concentration of displaced C atoms exceeds the concentration of implanted species by two to three orders of magnitude. The higher efficiency for Al and Si ions is attributed to the generation of collision cascades with a sufficiently high energy density to promote C{sub i}-clustering and reduce dynamic defect annealing. These C{sub i}-related clusters will subsequently dissolve during the post-implant annealing giving rise to enhanced C{sub i} injection. However, at annealing temperatures above 1500 °C, thermodynamic equilibrium conditions start to apply for the V{sub C}-concentration, which limit the net effect of the C{sub i} injection, and a competition between the two processes occurs.

  8. Comparative study of as-implanted and pre-damaged ion-beam-synthesized ZnS nanocrystallites in SiO sub 2

    CERN Document Server

    Gao, K Y; Grosshans, I; Hipp, W; Stritzker, B

    2002-01-01

    The semiconducting ZnS nanocrystallites were synthesized by sequential high dose ion implantation of Zn and S in thermally grown SiO sub 2 on Si(1 0 0) and subsequent rapid thermal annealing (RTA). Some samples were pre-implanted with Ar ions in order to investigate the influence of radiation induced damage on the formation of ZnS nanocrystallites. The crystal structure of the ZnS crystallites, their size distribution and the concentration depth profile were analyzed by X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS) and cross-sectional transmission-electron-microscopy (XTEM). The XRD results indicate, that the phase transition from cubic zinc blende to hexagonal wurtzite structure of ZnS nanocrystallites begins at temperatures below 1000 degree sign C. The RBS results show a clear redistribution of Zn and S after RTA annealing. The concentration of Zn is seriously reduced due to strong diffusion towards deeper regions and the surface, while Ar pre-implantation partially suppressed the c...

  9. New, fast corroding high ductility Mg-Bi-Ca and Mg-Bi-Si alloys, with no clinically observable gas formation in bone implants

    Energy Technology Data Exchange (ETDEWEB)

    Remennik, S., E-mail: saggym@gmail.com [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); Bartsch, I.; Willbold, E.; Witte, F. [Laboratory for Biomechanics and Biomaterials, Orthopaedic Clinic, Hannover Medical School, Anna-von-Borries-Str. 1-7, 30625 Hannover (Germany); Shechtman, D. [Department of Materials Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel); MSE, Iowa State University, Ames, Iowa 50011 (United States)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Biodegradable, biocompatible and highly ductile Mg alloys based on the Mg-Bi system have been produced by rapid solidification and extrusion processes. Black-Right-Pointing-Pointer The implants corroded fast within the first 4 weeks after implantation in rabbit bone, but no gas formation has been clinically observed. Black-Right-Pointing-Pointer The corrosion rate could be significantly reduced in vitro and in vivo by using high purity magnesium for the alloy production. - Abstract: Current approaches to initial corrosion rate reduction of biodegradable magnesium alloys include alloying with rare earth elements, mechanical processing, coatings and the use of metallic glasses. The latter has limited ductility needed for implant adaptively to various surgery procedures. Furthermore, slow corroding magnesium alloys, coatings or metallic glasses have not proved to be fully dissolvable in vivo. With this in mind, we have developed a new class of biocompatible, biodegradable ductile magnesium alloys with 40% elongation at room temperature. The alloys are based on the Mg-Bi system and undergo a series of production routes, which include rapid solidification (RS) and various extrusion processes. The Mg-Bi-Si (B-BS) system exhibited a high corrosion rates in vitro and was excluded from in vivo screening. In preliminary experiments of Mg-Bi-Ca (B-BX) in rabbit femur bones, the alloy corroded rapidly without any clinically visible gas formation. Only 30% of the B-BX implant remained uncorroded after 4 weeks of implantation. After using low iron Mg for implant preparation the corrosion rate of HP-B-BX was reduced in bone leaving 70% of the implant uncorroded after 4 weeks, while the corrosion in intramuscular and subcutaneous sites were still high leaving only 40% and 10% uncorroded after 4 weeks. The foreign body reaction was very mild and enhanced bone formation could be observed in the vicinity of the corroding implant. Thus, these

  10. 2-D analytical modeling of subthreshold current and subthreshold swing for ion-implanted strained-Si double-material double-gate (DMDG) MOSFETs

    Science.gov (United States)

    Goel, Ekta; Singh, Kunal; Singh, Balraj; Kumar, Sanjay; Jit, Satyabrata

    2017-09-01

    In this paper, the subthreshold behavior of ion-implanted strained-Si double-material double-gate (DMDG) MOSFETs has been analyzed by means of subthreshold current and subthreshold swing. The surface potential based formulation of subthreshold current and subthreshold swing is done by solving the 2-D Poisson's equations in the channel region using parabolic approximation method. The dependence of subthreshold characteristics on various device parameters such as gate length ratio, Ge mole fraction, peak doping concentration, projected range, straggle parameter etc. has been studied. The modeling results are found to be well matched with the simulation data obtained by a 2-D device simulator, ATLAS™, from SILVACO.

  11. Structural and optical properties of Er{sup 3+} doped SiO{sub 2}–Al{sub 2}O{sub 3}–GeO{sub 2} compounds prepared by a simple route

    Energy Technology Data Exchange (ETDEWEB)

    Filho, Fausto M. Faria [Instituto de Física, Universidade Federal de Goiás-UFG, Campus II, Caixa Postal 131, CEP 74001-970 Goiânia, GO (Brazil); Gonçalves, Rogéria R. [Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo-USP, Av. Bandeirantes, 3900, CEP 14040-901 Ribeirão Preto, SP (Brazil); Ribeiro, Sidney J.L. [Institute of Chemistry, São Paulo State University-UNESP, Rua Professor Francisco Degni, 55, CEP 14801-970 Araraquara, SP (Brazil); Maia, Lauro J.Q., E-mail: lauro@ufg.br [Instituto de Física, Universidade Federal de Goiás-UFG, Campus II, Caixa Postal 131, CEP 74001-970 Goiânia, GO (Brazil)

    2015-04-15

    Highlights: • We developed a simple route to obtain gels and powders using GeO{sub 2}, TEOS and TMAH solution. • Al{sub 6}Ge{sub 2}O{sub 13} crystalline nanoparticles embedded in amorphous matrix were obtained. • The Al{sub 2}O{sub 3} enhance Er{sup 3+} dispersion in GeO{sub 2}–SiO{sub 2} increasing its emission and the full width at half maximum from 41 to 56 nm. • The {sup 4}I{sub 13/2} Er{sup 3+} level lifetime varies between 4.8 and 5.6 ms (1533 nm emission). - Abstract: Samples of (1 − x)[0.70SiO{sub 2} + 0.30Al{sub 2}O{sub 3}] + xGeO{sub 2} compositions, containing x = 0.05, 0.10, 0.20, 0.30, 0.40 and 0.50, and doped with 1 mol% of Er{sup 3+}, were prepared by a mixed route (sol–gel process and Pechini method). Transparent gels were synthesized and homogeneous powders were obtained by heat treatments from 800 °C to 1050 °C. The final powders were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and high-resolution transmission electron microscopy. The optical properties were studied by photoluminescence measurements in the infrared region, and the average lifetime of the metastable state {sup 4}I{sub 13/2} of Er{sup 3+} ions and the full-width at half maximum (FWHM) were determined. A silica-rich amorphous phase and nanocrystallites with orthorhombic structure of Al{sub 6}Ge{sub 2}O{sub 13} phase were obtained. The samples present a broad emission centered at around 1532 nm under excitation at 977 nm, with a FWHM of 53 nm and a lifetime of 5.6 ms. The synthesized compounds by an easy chemical procedure are potentially applicable in integrated optical systems.

  12. Electrical activation of ion implanted Si in amorphous and crystalline In{sub 0.53}Ga{sub 0.47}As

    Energy Technology Data Exchange (ETDEWEB)

    Lind, A.G., E-mail: aglind@ufl.edu [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Gill, M.A. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States); Hatem, C. [Applied Materials, Gloucester, MA 01930 (United States); Jones, K.S. [Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2014-10-15

    The effect of pre-amorphization on the electrical activation of Si implants into In{sub 0.53}Ga{sub 0.47}As is investigated. Electrical measurements show that Si implants into pre-amorphized and crystalline In{sub 0.53}Ga{sub 0.47}As yield similar levels of activation (1.0 × 10{sup 19} cm{sup −3} in the pre-amorphized case and 9.0 × 10{sup 18}cm{sup −3} in the crystalline case) upon rapid thermal annealing for 5 s at 750 °C despite having very different types of resulting damage in the electrically active layers. The subsequent microstructural characterization by TEM indicates that the highly defective regrown layers in the pre-amorphized substrate leads to poor mobility in the active layers, which result in lower sheet resistances. The results suggest that solid phase epitaxy (SPE) in compound semiconductors can lead to some improved activation at lower temperatures and does not prevent substitutional activation of amphoteric dopants upon post SPE annealing.

  13. Indium flux synthesis of RE4Ni2InGe4 (RE = Dy, Ho, Er, and Tm): an ordered quaternary variation on the binary phase Mg5Si6.

    Science.gov (United States)

    Salvador, James R; Kanatzidis, Mercouri G

    2006-09-04

    The quaternary compounds RE4Ni2InGe4 (RE = Dy, Ho, Er, and Tm) were obtained as large single crystals in high yields from reactions run in liquid In. The title compounds crystallize in the monoclinic C2/m space group with the Mg(5)Si(6) structure type with lattice parameters a = 15.420(2) A, b = 4.2224(7) A, c = 7.0191(11) A, and beta = 108.589(2) degrees for Dy4Ni2InGe4, a = 15.373(4) A, b = 4.2101(9) A, c = 6.9935(15) A, and beta = 108.600(3) degrees for Ho4Ni2InGe4, a = 15.334(7) A, b = 4.1937(19) A, c = 6.975(3) A, and beta =108.472(7) degrees for Er4Ni2InGe4, and a = 15.253(2) A, b = 4.1747(6) A, c = 6.9460(9) A, and beta = 108.535(2) degrees for Tm4Ni2InGe4. RE4Ni2InGe4 formed in liquid In from a melt that was rich in the rare-earth component. These compounds are polar intermetallic phases with a cationic rare-earth substructure embedded in a transition metal and main group matrix. The rare-earth atoms form a highly condensed network, leading to interatomic distances that are similar to those found in the elemental lanthanides themselves. The Dy and Ho analogues display two maxima in the susceptibility, suggesting antiferromagnetic ordering behavior and an accompanying spin reorientation. The Er analogue shows only one maximum in the susceptibility, and no magnetic ordering was observed for the Tm compound down to 2 K.

  14. Y2O3:Yb,Er@mSiO2-Cu(x)S double-shelled hollow spheres for enhanced chemo-/photothermal anti-cancer therapy and dual-modal imaging.

    Science.gov (United States)

    Yang, Dan; Yang, Guixin; Wang, Xingmei; Lv, Ruichan; Gai, Shili; He, Fei; Gulzar, Arif; Yang, Piaoping

    2015-07-28

    Multifunctional composites have gained significant interest due to their unique properties which show potential in biological imaging and therapeutics. However, the design of an efficient combination of multiple diagnostic and therapeutic modes is still a challenge. In this contribution, Y2O3:Yb,Er@mSiO2 double-shelled hollow spheres (DSHSs) with up-conversion fluorescence have been successfully prepared through a facile integrated sacrifice template method, followed by a calcination process. It is found that the double-shelled structure with large specific surface area and uniform shape is composed of an inner shell of luminescent Y2O3:Yb,Er and an outer mesoporous silica shell. Ultra small Cu(x)S nanoparticles (about 2.5 nm) served as photothermal agents, and a chemotherapeutic agent (doxorubicin, DOX) was then attached onto the surface of mesoporous silica, forming a DOX-DSHS-Cu(x)S composite. The composite exhibits high anti-cancer efficacy due to the synergistic photothermal therapy (PTT) induced by the attached Cu(x)S nanoparticles and the enhanced chemotherapy promoted by the heat from the Cu(x)S-based PTT when irradiated by 980 nm near-infrared (NIR) light. Moreover, the composite shows excellent in vitro and in vivo X-ray computed tomography (CT) and up-conversion fluorescence (UCL) imaging properties owing to the doped rare earth ions, thus making it possible to achieve the target of imaging-guided synergistic therapy.

  15. Micro-CT and histological analysis of Ti6Al7Nb custom made implants with hydroxyapatite and SiO2-TiO2 coatings in a rabbit model.

    Science.gov (United States)

    Armencea, Gabriel; Berce, Cristian; Rotaru, Horatiu; Bran, Simion; Leordean, Dan; Coada, Camelia; Todea, Milica; Jula, Camelia Augusta; Gheban, Dan; Baciut, Grigore; Baciut, Mihaela; Campian, Radu Septimiu

    2015-01-01

    Bone defect reconstruction in the maxillofacial area comes as a necessity after traumatic, oncological or congenital pathology. Custom made implant manufacturing, such as selective laser melting (SLM), is very helpful when bone reconstruction is needed. In the present study we assessed the osseointegration of custom made implants made of Ti6Al7Nb with two different coatings: SiO2-TiO2 and hydroxyapatite, by comparing the bone mineral density (BMD) measured on micro-CT and the histological mineralized bone surrounding the implants. Custom made - cylindrical type - implants were produced by selective laser melting, coated with SiO2-TiO2 and hydroxyapatite and implanted in the rabbit femur. The animals (divided into 3 groups) were sacrificed at 1, 3 and 6 months and the implants were removed together with the surrounding bone. Bone mineral density and histological examination of the bone-implant surface was performed for each group. BMD and histological examination of the samples determined the quantity of mineralized bone at the implant site, showing a good percentage of mineralized bone for the coated implants at 1, 3 and 6 months. The measurements for the implants without coating showed a significant lower quantity of mineralized bone at 3 months compared with the implants with coating, and a good quantity of mineralized bone at 6 months, showing a process of demineralization followed by remineralization in the last month. The measurements of BMD showed similar results with the histological examination. The use of micro-CT and the measurement of BMD are a reliable, minimally invasive and a quick method of osseointegration assessment.

  16. Lysine adsorption on the silanized SiO{sub 2}-surface for immobilization of the estrogen receptor hER{sub {alpha}}

    Energy Technology Data Exchange (ETDEWEB)

    Cherkouk, C., E-mail: c.cherkouk@fzd.de [Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden Rossendorf, POB 510119, D-01314 (Germany); Rebohle, L.; Skorupa, W. [Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden Rossendorf, POB 510119, D-01314 (Germany)

    2011-03-15

    We investigated the adsorption of the L-lysine (200 mmol) molecule to a silanized SiO{sub 2} surface as a function of the pH value. The SSC (Spraying Spin Coating) method [Cherkouk et al., J. Colloid Interf. Sci. 337 (2009) 375-380] was applied to functionalize the SiO{sub 2} surface by using the (3-aminopropyl)trimethoxysilane (APMS) as coupling agent with a NH{sub 2} functional group. We adsorbed lysine molecules to the silane film for pH-values of 2.5, 7.5, 8.7, 9.5 and 13, which correspond to the di-cationic, cationic, zwitterinonic (pH 8.7 and 9.5) and the anionic charge state of lysine, respectively. The infrared spectroscopy is not suitable to investigate the system because the NH{sup 3+} signal at 1600 cm{sup -1} originating from the silane film overlaps with the infrared signal of the deprotonated carboxyl group of the lysine molecule. X-ray photoelectron spectroscopy (XPS) was used to measure the binding energies C 1s and N 1s as function of the pH value. This pH change affects the charge state which was fitted in the XPS spectra to obtain the optimal adsorption conditions at pH 7.5 of the lysine to the functionalized SiO{sub 2} surface.

  17. Formation technology of flat surface with epitaxial growth on ion-implanted (100)-oriented Si surface of thin silicon-on-insulator

    Science.gov (United States)

    Furukawa, Kiichi; Teramoto, Akinobu; Kuroda, Rihito; Suwa, Tomoyuki; Hashimoto, Keiichi; Sugawa, Shigetoshi; Suzuki, Daisuke; Chiba, Yoichiro; Ishii, Katsutoshi; Shimizu, Akira; Hasebe, Kazuhide

    2017-10-01

    For the development of three-dimensional devices, selective epitaxial growth (SEG) technology has attracted much attention. SEG has been applied to fabricate many devices and it is expected to be used in future manufacturing processes. Therefore, its characteristics must be examined in detail to extend its application. For the fabrication of a three-dimensional device structure, the selectivity of epitaxial growth must be accurately controlled not only on Si and SiO2, but also on different impurity-type silicon surfaces. In this work, we investigated some characteristics of the SEG process, especially focusing on the surface roughness after SEG. Both vapor phase epitaxy (VPE) and solid phase epitaxy (SPE) were performed on ion-implanted silicon-on-insulator (SOI) thin wafers. It was often reported that epitaxial growth is very sensitive to the crystal condition of the substrate on which the films are deposited. However, we first revealed that the impurity type (p- or n-type) and its concentration at the substrate surface markedly changed the roughness and incubation times of the deposition. From our results, SPE with the oxide cap layer formation is effective for maintaining almost the same flatness as the original wafer surface. It is also effective to employ the low-temperature H2/Xe plasma treatment after the SEG to reduce roughness.

  18. Mononuclear lanthanide single molecule magnets based on the polyoxometalates [Ln(W5O18)2]9- and [Ln(beta2-SiW11O39)2]13- (Ln(III) = Tb, Dy, Ho, Er, Tm, and Yb).

    Science.gov (United States)

    AlDamen, Murad A; Cardona-Serra, Salvador; Clemente-Juan, Juan M; Coronado, Eugenio; Gaita-Ariño, Alejandro; Martí-Gastaldo, Carlos; Luis, Fernando; Montero, Oscar

    2009-04-20

    The first two families of polyoxometalate-based single-molecule magnets (SMMs) are reported here. Compounds of the general formula [Ln(W(5)O(18))(2)](9-) (Ln(III) = Tb, Dy, Ho, and Er) and [Ln(SiW(11)O(39))(2)](13-) (Ln(III) = Tb, Dy, Ho, Er, Tm, and Yb) have been magnetically characterized with static and dynamic measurements. Slow relaxation of the magnetization, typically associated with SMM-like behavior, was observed for [Ln(W(5)O(18))(2)](9-) (Ln(III) = Ho and Er) and [Ln(SiW(11)O(39))(2)](13-) (Ln(III) = Dy, Ho, Er, and Yb). Among them, only the [Er(W(5)O(18))(2)](9-) derivative exhibited such a behavior above 2 K with an energy barrier for the reversal of the magnetization of 55 K. For a deep understanding of the appearance of slow relaxation of the magnetization in these types of mononuclear complexes, the ligand-field parameters and the splitting of the J ground-state multiplet of the lanthanide ions have been also estimated.

  19. Synthesis, mechanical properties and corrosion behavior of powder metallurgy processed Fe/Mg2Si composites for biodegradable implant applications.

    Science.gov (United States)

    Sikora-Jasinska, M; Paternoster, C; Mostaed, E; Tolouei, R; Casati, R; Vedani, M; Mantovani, D

    2017-12-01

    Recently, Fe and Fe-based alloys have shown their potential as degradable materials for biomedical applications. Nevertheless, the slow corrosion rate limits their performance in certain situations. The shift to iron matrix composites represents a possible approach, not only to improve the mechanical properties, but also to accelerate and tune the corrosion rate in a physiological environment. In this work, Fe-based composites reinforced by Mg 2 Si particles were proposed. The initial powders were prepared by different combinations of mixing and milling processes, and finally consolidated by hot rolling. The influence of the microstructure on mechanical properties and corrosion behavior of Fe/Mg 2 Si was investigated. Scanning electron microscopy and X-ray diffraction were used for the assessment of the composite structure. Tensile and hardness tests were performed to characterize the mechanical properties. Potentiodynamic and static corrosion tests were carried out to investigate the corrosion behavior in a pseudo-physiological environment. Samples with smaller Mg 2 Si particles showed a more homogenous distribution of the reinforcement. Yield and ultimate tensile strength increased when compared to those of pure Fe (from 400MPa and 416MPa to 523MPa and 630MPa, respectively). Electrochemical measurements and immersion tests indicated that the addition of Mg 2 Si could increase the corrosion rate of Fe even twice (from 0.14 to 0.28mm·year -1 ). It was found that the preparation method of the initial composite powders played a major role in the corrosion process as well as in the corrosion mechanism of the final composite. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Crystal chemistry and the role of ionic radius in rare earth tetrasilicates: Ba2RE2Si4O12F2 (RE = Er(3+)-Lu(3+)) and Ba2RE2Si4O13 (RE = La(3+)-Ho(3+)).

    Science.gov (United States)

    Fulle, Kyle; Sanjeewa, Liurukara D; McMillen, Colin D; Kolis, Joseph W

    2017-10-01

    Structural variations across a series of barium rare earth (RE) tetrasilicates are studied. Two different formulas are observed, namely those of a new cyclo-silicate fluoride, BaRE2Si4O12F2 (RE = Er(3+)-Lu(3+)) and new compounds in the Ba2RE2Si4O13 (RE = La(3+)-Ho(3+)) family, covering the whole range of ionic radii for the rare earth ions. The Ba2RE2Si4O13 series is further subdivided into two polymorphs, also showing a dependence on rare earth ionic radius (space group P{\\overline 1} for La(3+)-Nd(3+), and space group C2/c for Sm(3+)-Ho(3+)). Two of the structure types identified are based on dinuclear rare earth units that differ in their crystal chemistries, particularly with respect to the role of fluorine as a structural director. The broad study of rare earth ions provides greater insight into understanding structural variations within silicate frameworks and the nature of f-block incorporation in oxyanion frameworks. The single crystals are grown from high-temperature (ca 953 K) hydrothermal fluids, demonstrating the versatility of the technique to access new phases containing recalcitrant rare earth oxides, enabling the study of structural trends.

  1. Facile synthesis of an up-conversion luminescent and mesoporous Gd2O3 : Er3+@nSiO2@mSiO2 nanocomposite as a drug carrier.

    Science.gov (United States)

    Xu, Zhenhe; Li, Chunxia; Ma, Ping'an; Hou, Zhiyao; Yang, Dongmei; Kang, Xiaojiao; Lin, Jun

    2011-02-01

    In this paper, we report the facile synthesis of a bifunctional inorganic nanocomposite which is composed of core-shell structured mesoporous silica coated with up-conversion Gd2O3 : Er3+ particles. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, and photoluminescence (PL) spectra were used to characterize the samples. The results indicate that the nanocomposite with general 50 nm shell thickness and 300 nm core size shows typical ordered mesoporous characteristics (2.3 nm) and has spherical morphology with smooth surface and narrow size distribution. The bifunctional system shows unique green up-conversion emission under 980 nm NIR laser excitation even after loading with drug molecules. In addition, biocompatibility tests on L929 fibroblast cells using an MTT assay reveals low cytotoxicity of the system. Drug release tests suggest that the nanocomposite has a controlled drug release property with ibuprofen (IBU) as the model drug. Interestingly, the up-conversion emission intensity of the bifunctional carrier increases with the released amount of model drug, thus allowing the release process to be monitored and tracked by the change of up-conversion luminescence intensity. This composite can potentially act as a functional drug carrier system.

  2. Experiment for a measurement of the charge radius of the proton at the S-DALINAC and investigation of the fine structure of giant resonances in {sup 28}Si, {sup 48}Ca and {sup 166}Er with the help of the wavelet analysis; Experiment zur Messung des Ladungsradius des Protons am S-DALINAC und Untersuchung der Feinstruktur von Riesenresonanzen in {sup 28}Si, {sup 48}Ca und {sup 166}Er mit Hilfe der Waveletanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Pysmenetska, Inna

    2009-07-22

    The present thesis consists of two parts. In the first part a novel experimental method for the measurement of the proton root-mean-square radius at the S-DALINAC is presented. A setup based on semiconductor detectors is realized. In contrast to previous experiments it allows a simultaneous measurement of the momentum transfer dependence of the elastic electron scattering cross section. A possible suppression of the significant electron and bremsstrahlung background observed in a test experiment was investigated with the help of different methods, such as {delta}E-E telescopes, the time of flight method with a pulsed beam and pulse shape discrimination. The combination of these methods allows a reduction of the background at all scattering angles, which should allow a successful measurement. The response of the detector system was studied with the help of Monte-Carlo simulations with an emphasis on the dependence of the expected accuracy of different parameters. The second part of this work describes an investigation of the fine structure of giant resonances in {sup 28}Si, {sup 48}Ca and {sup 166}Er with the help of a wavelet analysis. The discrete wavelet transform was used for a background determination in spectra of the iso vector E1 and the M2 giant resonances in {sup 48}Ca. This allows the extraction of 1{sup -} und 2{sup -} level densities in the excitation energy region of the respective resonances with the help of a fluctuation analysis. A fluctuation analysis of the fine structure of the isoscalar E2 resonance in {sup 166}Er allows the extraction of the coherent widths of the 2{sup +} states. In the excitation energy region E{sub x}=10-16 MeV widths between 30 and 80 eV are found. The fine structure of the giant resonances is furthermore specified by characteristic scales. In this thesis scales in {sup 28}Si and {sup 48}Ca are extracted with the help of the above mentioned wavelet transform. In {sup 28}Si the isovector E1 and isoscalar E2 resonances were

  3. Micro-CT and histological analysis of Ti6Al7Nb custom made implants with hydroxyapatite and SiO2-TiO2 coatings in a rabbit model

    OpenAIRE

    ARMENCEA, GABRIEL; BERCE, CRISTIAN; ROTARU, HORATIU; BRAN, SIMION; LEORDEAN, DAN; COADA, CAMELIA; TODEA, MILICA; JULA, CAMELIA AUGUSTA; GHEBAN, DAN; BACIUT, GRIGORE; BACIUT, MIHAELA; CAMPIAN, RADU SEPTIMIU

    2015-01-01

    Background and aim Bone defect reconstruction in the maxillofacial area comes as a necessity after traumatic, oncological or congenital pathology. Custom made implant manufacturing, such as selective laser melting (SLM), is very helpful when bone reconstruction is needed. In the present study we assessed the osseointegration of custom made implants made of Ti6Al7Nb with two different coatings: SiO2-TiO2 and hydroxyapatite, by comparing the bone mineral density (BMD) measured on micro-CT and t...

  4. Cochlear Implants

    Science.gov (United States)

    ... implant procedure Welcome to the Food and Drug Administration (FDA) website on cochlear implants. Cochlear implants are electronic hearing devices. Doctors implant cochlear implants into people ...

  5. Porous SiO{sub 2} nanofiber grafted novel bioactive glass–ceramic coating: A structural scaffold for uniform apatite precipitation and oriented cell proliferation on inert implant

    Energy Technology Data Exchange (ETDEWEB)

    Das, Indranee [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); De, Goutam, E-mail: gde@cgcri.res.in [Nano-Structured Materials Division, CSIR-Central Glass and Ceramic Research Institute, Kolkata 700032 (India); Hupa, Leena [Johan Gadolin Process Chemistry Centre, Åbo Akademi University, FI-20500 Åbo (Finland); Vallittu, Pekka K. [Turku Clinical Biomaterials Centre—TCBC, University of Turku, FI-20520 Turku (Finland); Institute of Dentistry, University of Turku, Department of Biomaterials Science and City of Turku, Welfare Division, Turku (Finland)

    2016-05-01

    A composite bioactive glass–ceramic coating grafted with porous silica nanofibers was fabricated on inert glass to provide a structural scaffold favoring uniform apatite precipitation and oriented cell proliferation. The coating surfaces were investigated thoroughly before and after immersion in simulated body fluid. In addition, the proliferation behavior of fibroblast cells on the surface was observed for several culture times. The nanofibrous exterior of this composite bioactive coating facilitated homogeneous growth of flake-like carbonated hydroxyapatite layer within a short period of immersion. Moreover, the embedded porous silica nanofibers enhanced hydrophilicity which is required for proper cell adhesion on the surface. The cells proliferated well following a particular orientation on the entire coating by the assistance of nanofibrous scaffold-like structural matrix. This newly engineered composite coating was effective in creating a biological structural matrix favorable for homogeneous precipitation of calcium phosphate, and organized cell growth on the inert glass surface. - Highlights: • Fabricated porous SiO{sub 2} nanofibers grafted composite bioactive glass–ceramic coating on inert glass. • The newly engineered coating facilitates uniformly dense apatite precipitation. • Embedded porous silica nanofibers enhance hydrophilicity of the coated surface. • Cells proliferate well on the entire coating following a particular orientation by the assistance of nanofibers. • The coatings have potential to be used as biological scaffold on the surface of implants.

  6. Thermal evolution of surface blistering and exfoliation due to ion-implanted hydrogen monomers into Si Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket

    Energy Technology Data Exchange (ETDEWEB)

    Liang, J.H., E-mail: jhliang@ess.nthu.edu.tw [Institute of Nuclear Engineering and Science, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Hu, C.H.; Bai, C.Y. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Chao, D.S. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 300, Taiwan (China); Lin, C.M. [Department of Applied Science, National Hsinchu University of Education, Hsinchu 300, Taiwan (China)

    2012-08-01

    This study investigated the dependence of surface blistering and exfoliation phenomena on post-annealing time in H{sup +}-implanted Si Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket . Czochralski-grown n-type Si Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket wafers were room-temperature ion-implanted with 40 keV hydrogen monomers to a fluence of 5 Multiplication-Sign 10{sup 16} cm{sup -2}, and followed by furnace annealing treatments at 400 and 500 Degree-Sign C for various durations ranging from 0.25 to 3 h. The corresponding analysis results for Si Left-Pointing-Angle-Bracket 1 0 0 Right-Pointing-Angle-Bracket (Liang et al., 2008); (Bai, 2007) were adopted in order to make comparisons. The evolution of blister formation and growth for Si Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket at 400 Degree-Sign C has a shorter characteristic time compared to Si Left-Pointing-Angle-Bracket 1 0 0 Right-Pointing-Angle-Bracket . However, there is a longer characteristic time when annealing takes place at 500 Degree-Sign C. In addition, no craters were observed for Si Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket annealed at 400 Degree-Sign C while the opposite is true for Si Left-Pointing-Angle-Bracket 1 0 0 Right-Pointing-Angle-Bracket . The evolution of crater development for Si Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket annealed at 500 Degree-Sign C has a longer characteristic time compared to Si Left-Pointing-Angle-Bracket 1 0 0 Right-Pointing-Angle-Bracket . These results are attributed to the fact that compared to Si Left-Pointing-Angle-Bracket 1 0 0 Right-Pointing-Angle-Bracket , Si Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket has a smaller surface binding energy of silicon atoms and a larger areal number density of silicon atoms on the plane perpendicular to the incident-ion axis. Furthermore, Si Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket has a

  7. Hvem er vi? Hvem er de?

    DEFF Research Database (Denmark)

    Kryger, Niels

    2016-01-01

    Kommentaren tager afsæt i initiativer i de pædagogiske faglige foreninger i Europa EERA) og i Norden (NERA) og argumenterer for at det er forpligtelse for os som nordiske og europæiske pædagogiske forskere at gå op imod de stadigt mere ekskluderende vi-konstruktioner, som er blevet formuleret i for...

  8. Cochlear implant

    Science.gov (United States)

    Hearing loss - cochlear implant; Sensorineural - cochlear; Deaf - cochlear; Deafness - cochlear ... of the cochlear implant. WHO USES A COCHLEAR IMPLANT? Cochlear implants allow deaf people to receive and process ...

  9. Puf er plat

    DEFF Research Database (Denmark)

    Hansen, Pelle Guldborg; Zeller, Clara

    2015-01-01

    Der er stort set ingen, der har fattet, hvad nudging egentlig er. Et nudge er nemlig hverken ”et lille blidt skub”, eller ”en helt ny videnskabelig metode [der] kan ændre vores adfærd, uden vi opdager det - og uden det koster os noget”, ligesom det heller ikke er ”en måde at friste kunder til at ...

  10. Paediatric cochlear implantation

    African Journals Online (AJOL)

    Chantel

    The internal portion consists of a multi- channel electrode array that is implanted in the cochlea and is attached to a receiv- er/stimulator, an antenna and a .... ties, cerebral palsy, sensory integra- tion problems, blindness and autism can be considered as CI candidates. The literature shows that CIs benefit children with hear-.

  11. Demokratiets krise er lovende

    DEFF Research Database (Denmark)

    Thomassen, Bjørn; Harrebye, Silas Fehmerling

    2016-01-01

    Demokratiet er i krise. Men den er langtfra bundløs. For når eksisterende partier, traditionelle virksomheder, den velkendte fagforening og de gamle medier udfordres, opstår muligheden for et sceneskift. Meget peger på, at det er på vej...

  12. Efter cochlear implant

    DEFF Research Database (Denmark)

    Højen, Anders

    2007-01-01

      Dit barn har netop fået et cochlear implant. Hvad nu? Skal barnet fokusere udelukkende på at lære talt sprog, eller skal det også lære/fortsætte med tegnsprog eller støttetegn? Det er et vanskeligt spørgsmål, og før valget foretages, er det vigtigt at vurdere hvilke konsekvenser valget har, dels...... for den sproglige udvikling isoleret set, og dels for barnets udvikling ud fra en helhedsbetragtning. Dette indlæg fokuserer på, hvilke forventninger man kan have til cochlear implant-brugeres sproglige udvikling med talt sprog alene, hhv. med to sprog (tale og tegn). Disse forventninger er baseret på...

  13. Efter cochlear implant

    DEFF Research Database (Denmark)

    Højen, Anders

    Dit barn har netop fået et cochlear implant. Hvad nu? Skal barnet fokusere udelukkende på at lære talt sprog, eller skal det også lære/fortsætte med tegnsprog eller støttetegn? Det er et vanskeligt spørgsmål, og før valget foretages, er det vigtigt at vurdere hvilke konsekvenser valget har, dels...... for den sproglige udvikling isoleret set, og dels for barnets udvikling ud fra en helhedsbetragtning. Dette indlæg fokuserer på, hvilke forventninger man kan have til cochlear implant-brugeres sproglige udvikling med talt sprog alene, hhv. med to sprog (tale og tegn). Disse forventninger er baseret på...

  14. Characterization of high-dose and high-energy implanted gate and source diode and analysis of lateral spreading of p gate profile in high voltage SiC static induction transistors

    Science.gov (United States)

    Onose, Hidekatsu; Kobayashi, Yutaka; Onuki, Jin

    2017-03-01

    The effect of the p gate dose on the characteristics of the gate-source diode in SiC static induction transistors (SIT) was investigated. It was found that a dose of 1.5 × 1014 cm-2 yields a pn junction breakdown voltage higher than 60 V and good forward characteristics. A normally on SiC SIT was fabricated and demonstrated. A blocking voltage higher than 2.0 kV at a gate-source voltage of -50 V and on-resistance of 70 mΩ cm2 were obtained. Device simulations were performed to investigate the effect of the lateral spreading. By comparing the measured I-V curves with simulation results, the lateral spreading factor was estimated to be about 0.5. The lateral spreading detrimentally affected the electrical properties of the SIT made using implantations at energies higher than 1 MeV.

  15. Vreden er over os

    DEFF Research Database (Denmark)

    Mehlsen, Camilla

    2006-01-01

    Urolige elever, cyklister - der giver fuck-finger, aggressive demonstranter. Samtiden er på vej ind i en æra domineret af vrede, siger rektor Lars-Henrik Schmidt, der er aktuel med bogen 'Om vreden'. Udgivelsesdato: Juni...

  16. Hvor anvendelig er PKI?

    OpenAIRE

    Nielsen, Jon Magne

    2006-01-01

    Denne oppgaven ser på bruken av elektronisk ID i statlige etater i Norge i dag. Det ses spesielt på om bruken av tekologien PKI er en god løsning på etatenes behov på dette området. Som utgangspunkt for analysen er det sett spesielt på to statlige etater. Disse etatenes behov og bruk av elektronisk ID generelt og PKI spesielt blir undersøkt. Det er videre gjort rede for hvilke lover, forskrifter og andre førende dokumenter som danner de formelle rammebetingelsene for etaters bruk av PKI. ...

  17. Improvement of biodegradability, bioactivity, mechanical integrity and cytocompatibility behavior of biodegradable mg based orthopedic implants using nanostructured Bredigite (Ca7MgSi 4O 16) bioceramic coated via ASD/EPD technique.

    Science.gov (United States)

    Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Vashaee, Daryoosh; Tayebi, Lobat

    2014-12-01

    This research explored the influence of surface modification of AZ91 Mg alloy on the biodegradation, bioactivity, mechanical integrity and cytocompatibility of the alloy. For this purpose, a nanostructured bredigite (Ca7MgSi4O16) ceramic coating was prepared on biodegradable AZ91 Mg alloy through anodic spark deposition and electrophoretic deposition method. The phase composition and surface morphology of the coated alloy were characterized by X-ray diffraction, scanning electron microscope and transmission electron microscope. The properties of samples were investigated by electrochemical measurements, immersion test, compression examination and cell culturing. The results showed that the degradation resistance, bioactivity, mechanical integrity and cytocompatibility of biodegradable Mg alloy were improved by the anodic spark deposition and electrophorretic deposition of the nanostructured bredigite coating. Therefore, the nanostructured bredigite ceramic coating is identified as a good coating for AZ91 Mg alloy for the purpose of making biodegradable metallic orthopedic implants.

  18. Sol-gel synthesis and characterization of SiO{sub 2}/PEG hybrid materials containing quercetin as implants with antioxidant properties

    Energy Technology Data Exchange (ETDEWEB)

    Catauro, Michelina; Bollino, Flavia [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 21, 81031 Aversa (Italy); Gloria, Antonio [Institute of Polymers, Composites and Biomaterials - National Research Council of Italy, V.le J. F. Kennedy 54 - Mostra d’Oltremare Pad. 20, 80125 Naples (Italy)

    2016-05-18

    In the present work, Silica/Polyethylene glycol (PEG) hybrid nanocomposites containing an antioxidant agent, the quercetin, were synthesized via sol-gel to be used as implants with antioxidant properties. Fourier transform infrared (FT-IR) analysis proved that a modification of both polymer and quercetin occurs due to synthesis process. Scanning electron microscope (SEM) showed that the proposed materials were hybrid nanocomposites. The bioactivity was ascertained by soaking the samples in a simulated body fluid (SBF).

  19. Metabolomics er fremtiden

    DEFF Research Database (Denmark)

    Pedersern, Birger

    2010-01-01

    Forskningen i fødevarer har fået et potent redskab i hånden. Metabolomics er vejen frem, mener professor Søren Balling Engelsen fra Københavns Universitet......Forskningen i fødevarer har fået et potent redskab i hånden. Metabolomics er vejen frem, mener professor Søren Balling Engelsen fra Københavns Universitet...

  20. Analysis of the Forward I- V Characteristics of Al-Implanted 4H-SiC p-i- n Diodes with Modeling of Recombination and Trapping Effects Due to Intrinsic and Doping-Induced Defect States

    Science.gov (United States)

    Megherbi, M. L.; Pezzimenti, F.; Dehimi, L.; Saadoune, A.; Della Corte, F. G.

    2018-02-01

    In this paper, the impact of silicon carbide intrinsic defect states, such as Z1/2 and EH6/7 centers, on the forward current-voltage curves of aluminum (Al)-implanted 4H-SiC p-i- n diodes is investigated by means of a physics-based device simulator. During the simulations, an explicit carrier trap effect due to an electrically active defect concentration produced by the Al+ ion implantation process in the anode region was also taken into account. The obtained current-voltage characteristics are compared with those measured experimentally for several samples at different current levels. It is found that intrinsic defect densities as high as the epilayer doping may lead to undesirable device properties and instability of the forward bias behavior. The diode ideality factor and the series resistance increase with the increase of defects and could be controlled by using high-purity epi-wafers. Furthermore, due to their location in the bandgap and capture cross-sections, the impact of Z1/2 centers on the device electrical characteristics is more severe than that of EH6/7 centers.

  1. High-efficiency near-infrared emission from Bismuth-doped SiO0.73 thin films fabricated by ion implantation technology.

    Science.gov (United States)

    Lin, Shaobing; Zhang, Xiaowei; Zhang, Pei; Tan, Dameng; Xu, Jun; Li, Wei; Chen, Kunji

    2016-02-01

    Over the past decade, the possibility of near-infrared light generation and amplification on chip has attracted great interest for future monolithic integrated optical components. In this Letter, we demonstrated a CMOS-compatible method to fabricate amorphous SiO0.73 thin films doped with Bi ions. It exhibited highly improved σ(em)×τ of up to 4.2×10(-23) cm2 s and greatly enhanced near-infrared characteristic emission originated from Bi ions by nearly 60 times via Si nanocrystal size control. We anticipated that this Bi-doped near-infrared light emitter would be a new starting point for future research in the field of optoelectronic integration.

  2. Porosity as a function of stoichiometry and implantation temperature in Ge/Si{sub 1−x}Ge{sub x} alloys

    Energy Technology Data Exchange (ETDEWEB)

    Alkhaldi, H. S. [Department of Electronic Materials Engineering, Australian National University, Canberra ACT 2601 (Australia); Department of Physics in Jubail Education college, Dammam University, Dammam 1982 (Saudi Arabia); Kremer, F. [Centre for Advanced Microscopy, Australian National University, Canberra ACT 2601 (Australia); Bierschenk, T.; Williams, J. S.; Ridgway, M. C. [Department of Electronic Materials Engineering, Australian National University, Canberra ACT 2601 (Australia); Hansen, J. L.; Nylandsted-Larsen, A. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

    2016-03-07

    The development of porosity in single-crystal germanium and silicon-germanium alloys (c-Si{sub 1−x} Ge{sub x}) of (100) orientation was studied under bombardment with 140 keV Ge{sup −} ions over a wide range of temperatures (−180 to 400 °C) and ion fluences up to 1 × 10{sup 18} ions/cm{sup 2}. The surface swelling and morphology were investigated using multi-characterization techniques including optical profilometry, transmission electron microscopy, and scanning electron microscopy. The initiation of porosity and the evolution of the near-surface microstructure strongly depend on the ion fluence, the irradiation temperature, and the stoichiometry of the substrate. Significant results and new findings include: (i) the fact that, over the entire temperature and stoichiometry range, porosity is only developed once the substrate is rendered amorphous; (ii) with increasing Si content in the alloy, the onset of porosity is pushed to higher fluences; (iii) porosity is observed for Si contents in the alloy up to 23% but not higher under the irradiation conditions used; and (iv) in all cases the initiation of porosity was observed to occur at the surface of the amorphous alloy above a threshold fluence. This last result strongly suggests that the mechanism for initiation of porosity is via preferential vacancy segregation and clustering at the surface of the amorphous alloy. Particularly at elevated temperatures, preferential sputtering of the Si-Ge atomic species in the alloy also plays an important role in developing the surface topography and porosity in alloys. Such effects are discussed along with the implications of our results for mechanisms of porosity in Ge and its alloys.

  3. Jeg Er blevet FRANKofil

    DEFF Research Database (Denmark)

    Andersson, Lasse

    2014-01-01

    afhængig af Frank Underwood fra serien House of Cards på den fremadstormende TV-streamingstjenesten Netflix. Jeg har opdaget et nyt internetbaseret datingforhold. Et surrealt, fedt miks af det kyniske og joviale personificeret i karakteren Frank Underwood, som er helt igennem ubehagelig, men fantastisk...... spillet af Kevin Spacey. Og tak til Spacey der for en tid har forladt teateret ’The Old Vic’ i London for at begejstre mig. Der er generelt to årsager til mine FRANKofile tilbøjeligheder. For det første er Netflix’s remake af den tyve år gamle BBC serie House of Cards efter min menig et stykke tv...... anden grund, til at jeg er blevet Frankofil, er, at jeg ikke skal sidde og vente på næste søndag efter søndag efter søndag for at få lov at se næste afsnit. Netflix lagde alle tretten timer af sæson 2 ud på nettet. Jeg afgør selv, hvornår jeg skal have mere Frank! Men på trods af mit narkomanlignende...

  4. Innovation er brugerdreven!

    DEFF Research Database (Denmark)

    Helms, Niels Henrik

    2008-01-01

    Brugerdreven innovation er blevet svaret på mange af de udfordringer, som vores moderne samfund står overfor.Det er skrevet ind i såvel regeringsgrundlaget som i de forskellige tiltag, som skal ruste Danmark i forhold til globaliseringen. Vi har ifølge argumentationen her enrække særlige forudsæt......Brugerdreven innovation er blevet svaret på mange af de udfordringer, som vores moderne samfund står overfor.Det er skrevet ind i såvel regeringsgrundlaget som i de forskellige tiltag, som skal ruste Danmark i forhold til globaliseringen. Vi har ifølge argumentationen her enrække særlige...... forudsætninger: samspillet mellem virksomhederne, samspillet mellem forskning, virksomheder og fx erhvervspolitiske tiltag, den særlige danske designtradition. Samtidig er det netop innovationen og især den brugerdrevne innovation, som giver og isærdeleshed skal give Danmark en rolle i en globaliseret økonomi...

  5. Production of Rare Earth Isotope Beams for Radiotracer-DLTS on SiC

    CERN Multimedia

    2002-01-01

    Electrical properties of semiconductors are extremely sensitive to minor traces of impurities and defects. This fact allows to intentionally modify material properties and is thus the very basis of semiconductor electronics and optoelectronics. In the present project, electronic properties and doping effects of rare-earth elements in the technologically important semiconductor SiC are to be investigated using optical and electrical characterization techniques like Photoluminescence, Deep Level Transient Spectroscopy and Thermal Admittance Spectroscopy. By using the elemental transmutation of radioactive isotopes as a tracer, it will be guaranteed that the impurity-related band gap states can definitively be distinguished from intrinsic or process-induced defects. For SiC up to now only detailed investigation of Er- related deep levels have been reported, preliminary data exist for Sm- and Gd- impurities. In this project we propose the implantation of Pr and Eu isotopes for detailed level studies.

  6. Tale er guld

    DEFF Research Database (Denmark)

    Juel Henrichsen, Peter

    2014-01-01

    Mange danske kommuner er parate til at indfase automatisk talegenkendelse, men er samtidig nervøse efter en lang række dårlige businesscases i den nærmere fortid. Der klages over høje licenspriser og lavt serviceniveau, den typiske virkning af et de facto monopol på leverandørsiden. Denne artikel...... området - som vi håber at se i 2014 - en begivenhed som præcis kunne løsne den nuværende deadlock og åbne et milliardstort marked for taleteknologi i det offentliges tjeneste....

  7. Bioenergi er blevet moderne

    DEFF Research Database (Denmark)

    Sønderberg Petersen, L.

    2003-01-01

    Risø har udgivet en rapport om moderne bioenergi. Den slår fast, at biomasse er en ligeså værdifuld ressource som vind, og at Danmark vil kunne spille en væsentlig rolle i udviklingen af den teknologi, der skal til for at udnytte hele dens potentiale.......Risø har udgivet en rapport om moderne bioenergi. Den slår fast, at biomasse er en ligeså værdifuld ressource som vind, og at Danmark vil kunne spille en væsentlig rolle i udviklingen af den teknologi, der skal til for at udnytte hele dens potentiale....

  8. Effect of Si, Mn, Sn on Tensile and Corrosion Properties of Mg-4Zn-0.5Ca Alloys for Biodegradable Implant Materials

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Dae Hyun; Nam, Ji Hoon; Lee, Byeong Woo; Park, Ji Yong; Shin, Hyun Jung; Park, Ik Min [Pusan National University, Busan (Korea, Republic of)

    2015-03-15

    Effect of elements Si, Mn, Sn on tensile and corrosion properties of Mg-4Zn-0.5Ca alloys were investigated. The results of tensile properties show that the yield strength, ultimate tensile strength and elongation of Mg-4Zn-0.5Ca alloy increased significantly with the addition of 0.6 wt% Mn. This is considered the grain refinement effect due to addition of Mn. However addition of 0.6 wt% Si decreased yield strength, ultimate tensile strength and elongation. The bio-corrosion behavior of Mg-4Zn-0.5Ca-X alloys were investigated using immersion tests and potentiodynamic polarization test in Hank's solution. Immersion test showed that corrosion rate of Mg-4Zn-0.5Ca-0.6Mn alloy was the lowest rate and addition of 1.0 wt% Sn accelerated corrosion rate due to micro-galvanic effect in α-Mg/CaMgSn phases interface. And corrosion potential (E{sub c}orr) of Mg-4Zn-0.5Ca-0.6Mn alloy was the most noble among Mg-4Zn-0.5Ca-X alloys.

  9. Ondskaben er fortryllende

    DEFF Research Database (Denmark)

    Schubart, Rikke

    2013-01-01

    Indlæg om tv-serien Once Upon a Time (2011-), der hører til genren fairytale fantasy, der blander eventyr og fantasy. Her bliver alle eventyr brugt i en fortælling om alle beboere i en lille by, der ikke ved, at de i virkeligheden er eventyr-karakterer....

  10. Riget - alt er tilladt

    DEFF Research Database (Denmark)

    Agger, Gunhild

    2017-01-01

    Riget indtager en nøglestilling, når overgangen mellem faser i Triers produktion skal karakteriseres. Riget danner bro mellem den billedfascination og de radikale stileksperimenter, der præger Triers tidlige produktion, og den genre- og plotbevidsthed, der er typisk for film som Breaking the Wave...... (1996) og Dancer in the Dark (2000). Artiklen analyserer hvordan....

  11. It er godt - basta!

    DEFF Research Database (Denmark)

    Bundsgaard, Jeppe

    2012-01-01

    Der er offentlig konsensus om at it i undervisningen fører til øget faglighed. Men it kan lige så godt resultere i ringere undervisning som i bedre - og ofte anvendes it helt traditionelt og fantasiløst....

  12. Hvad er tidligt sprog

    DEFF Research Database (Denmark)

    Skriver Jensen, Anders

    2009-01-01

    Forfatteren argumenterer for at "early literacy" kan oversættes til "tidligt sprog"; særligt når der er tale om en helhedsorienteret tilgang med vægt på sprog som et alsidigt medie for kommunikation- og betydningsskabelse. Med inspiration fra Jerome Bruners kulturpsykologi diskuteres mulige...

  13. Litteratur er nyttig

    DEFF Research Database (Denmark)

    Kaspersen, Peter

    2012-01-01

    Den anmeldte bog er en forskningsbaseret debatbog om hvilken nytteværdi litteratur har. Bogen placeres i sammenhæng med en række bøger på nordiske sprog og engelsk om litteraturens, litteraturundervisningens og -forskningens legitimitet. Argumentatioen i bogen bygger på Bakhtins litteratursyn, og...

  14. Ideologi er noget bras

    DEFF Research Database (Denmark)

    Hansen, Brian Benjamin; Jøker Bjerre, Henrik

    fra den slovenske filosof Slavoj Zizek stilles imidlertid det spørgsmål i bogen, om ideologien idag ikke blot har taget en anden form. Vi lever i dag ikke i post-ideologiske tider. Snarere er braset selv – X Factor, forbrugsobjekter, underholdning, følelser og balloner – blevet den næsten usynlige...

  15. er 1999

    DEFF Research Database (Denmark)

    Jensen, J. P.; Søndergaard, M.; Jeppesen, E.

    land bidrager med flest næringsstoffer til søerne Stoftilførslen af såvel fosfor som kvælstof til søerne har i 1999 som tidligere år været domineret af tilførslen fra det åbne land, der gen-nemsnitligt har bidraget med ca. 73 % af fosfortilførslen og ca. 78 % af kvælstoftilførslen (Fig. 0...... for de mest belastede søer. Således er både fosfor- og kvælstof-bidraget fra byspildevand og industrispildevand fra 1989 til 1999 reduceret meget markant fra ca. 22 % til ca. 3 %. Figur 0.1 Kildefordeling for fosfor- og kvælsstoftilførslen til søerne i 1999. Grå: Åbent land (landbrug + baggrund). Sort...... af overvågningssøerne, efter at søer-ne er blevet klarvandede som følge af ændringer i fiskebestanden. I halvdelen af søerne var kvælstof-tilbageholdelsen i 1999 højere end 26 %. Medianen og gennemsnittet for den absolutte kvælstoftilbagehol-delse var 93 og 111 mg N m-2 dag-1 svarende til 340 og 405...

  16. Hvad er alternativet?

    DEFF Research Database (Denmark)

    Jensen, Niels Rosendal

    2015-01-01

    Anmeldelsen af Mårtenssons "Konkurrencestatens pædagogik" præsenterer dels forfatterens kritik af og alternativ til den igangværende reform af folkeskolen, dels advarer den mod at forfalde til konspirationsteori. Endelig peger den på, at Mårtenssons såkaldte alternativ er gammel vin på nye flaske...

  17. Patienten - hvor er patienten?

    DEFF Research Database (Denmark)

    Nielsen, Gitte; Dau, Susanne

    2011-01-01

    på, hvad der historisk og nutidigt karakteriserer teori og praksis, samt forholdet herimellem. I den empiriske del er der, med udgangspunkt i Gadamers hermeneutiske tilgang, foretaget tre kvalitative forkusgruppeinterview. Ét af sygeplejestuderende, ét af kliniske vejledere og ét af undervisere...

  18. Er danskerne racister?

    DEFF Research Database (Denmark)

    Necef, Mehmet Ümit; Bech, Henning

    Igennem de seneste årtier er det blevet almindeligt at tale om, at der er en udbredt racisme i Danmark. Påstande om danskernes racisme, fremmedhad og diskrimination optræder dagligt i offentligheden og i medierne, og der henvises ofte til, hvad ’forskerne’ og de ’videnskabelige undersøgelser’ siger...... om emnet. Der kan da næppe heller være tvivl om, at der forekommer racistiske holdninger hos nogle danskere. Men er problemet så stort, som det gøres til i den offentlige debat? Bogen ønsker at afklare, hvorvidt der er videnskabelig dokumentation for påstandene om danskernes racisme. Den går i dybden...... med en række forskeres og eksperters udtalelser på området og præsenterer en grundig analyse af deres fremstilling af dansk racisme i forhold til emner som kultur, seksualitet, kriminalitet og arbejdsmarked....

  19. Nordslesvigeren er nr. 1

    DEFF Research Database (Denmark)

    Christensen, Steffen Lind

    2015-01-01

    Historien om de nordslesvigske krigsdeltagere under 1. Verdenskrig er traditionelt blevet behandlet i et nationalt perspektiv. Her benævnes soldaterne oftest som ’danske’. Denne artikel undersøger, hvordan nordslesvigske soldater på Østfronten selv udtrykte deres identitet i krigssituationen...

  20. Sol-gel synthesis and characterization of SiO2/PCL hybrid materials containing quercetin as new materials for antioxidant implants.

    Science.gov (United States)

    Catauro, Michelina; Bollino, Flavia; Papale, Ferdinando; Piccolella, Simona; Pacifico, Severina

    2016-01-01

    The development of biomaterials with intrinsic antioxidant properties could represent a valuable strategy for preventing peri-implant disease onset. In this context quercetin, a naturally occurring flavonoid, has been entrapped, at different weight percentages in a silica/poly(ε-caprolactone)-based hybrid material by a sol-gel route. FT-IR and UV spectroscopic techniques were employed in order to characterize the hybrids. FT-IR analysis indicated changes in stretching frequencies of the quercetin dienonic moiety, suggesting that a flavonol oxidized derivative was formed during the sol-gel process. The establishment of hydrogen-bonded interactions between quercetin and silica and polymer matrices,was strongly affected by the amount of polymer. Poly(ε-caprolactone) did not interact with quercetin when it was loaded at high doses (50 wt.%). The morphology of the synthesized materials was observed by using SEM. The obtained images proved that the materials are hybrid nanocomposites. Their bioactivity was shown by the formation of a hydroxyapatite layer on samples' surface soaked in a fluid simulating the composition of the human plasma. The antiradical properties of the investigated systems were evaluated by DPPH and ABTS methods and their cytotoxicity by the MTT assay. Data obtained revealed that the synthesized materials are biocompatible and that the hybrid system,with 6 wt.% of PCL and 15 wt.% of quercetin, produced the strongest antiradical efficacy.

  1. Er HR ude i tovene?

    DEFF Research Database (Denmark)

    Poulfelt, Flemming

    2015-01-01

    HR: Er der behov for nytænkning i HR-land? Artikler i Harvard Business Review - bakket op af en dansk undersøgelse - konkluderer, at HR stadig mangler gennemslagskraft i virksomhederne. Er HR ude i tovene? ... For i undersøgelsen "Ny Dansk Ledelse" (maj 2015), som er baseret på danske lederes...

  2. Facebook er internettet nu

    DEFF Research Database (Denmark)

    Tække, Jesper

    2014-01-01

    Den store vision for world wide web var, at alle kunne få ubegrænset adgang til alverdens information. www var mangfoldigt og anarkistisk. I dag er der rigtig mange, der kun bruger nettet til at være på Facebook. Hvad bruger Facebook det til? Og hvad gør det ved vores udsyn?......Den store vision for world wide web var, at alle kunne få ubegrænset adgang til alverdens information. www var mangfoldigt og anarkistisk. I dag er der rigtig mange, der kun bruger nettet til at være på Facebook. Hvad bruger Facebook det til? Og hvad gør det ved vores udsyn?...

  3. Hvad er en by?

    DEFF Research Database (Denmark)

    Parby, Jakob; Thelle, Mikkel

    2011-01-01

    Nytænkning. Med de moderne megabyer er det slut med at forestille sig byen som noget, man planlægger og giver form. Vi skal lære at se dem som vildtvoksende urbane landskaber. Artikel om megabyer, byudvikling og forestillingen om byen gennem tiderne. Skrevet delvist i anledning af åbningen af...... udstillingen Citambulos på Københavns Museum, der handlede om Mexico City....

  4. Hvis er Himmeriget?

    DEFF Research Database (Denmark)

    Holst, Søren

    2007-01-01

    Udtrykket "de fattige i ånden", som kendes fra Bjergprædikenen i Matthæusevangeliet, forekommer også i to af Dødehavsrullerne. Artiklen undersøger disse tekster og argumenterer for, at udtrykket ikke betegner en særligt "åndelig" fattigdom, men derimod de konkret økonomisk fattige, som er "af ånd...

  5. er 2000

    DEFF Research Database (Denmark)

    Jensen, J. P.; Søndergaard, M.; Jeppesen, E.

    ændringer i be-lastningen af vand-miljøet med nærings-salte. Med NOVA er programmet udvidet til at omfatte både vand-miljøets tilstand i bredeste forstand og miljøfremmede stoffer og tungmetaller. Danmarks Miljøundersø-gelser har som sektor-forskningsinstitu-tion i Miljøministeriet til opgave at forbedre og...

  6. Han er her endnu

    DEFF Research Database (Denmark)

    Bonde, Lisbeth

    2012-01-01

    Interview med den kinesiske aktivist og billedkunstner Ai Weiwei, der sad fængslet i 81 dage i 2011. Hans pas er stadig (i februar 2014) inddraget af myndighederne, så han kan ikke forlade landet, selv om han har betalt en bøde på 13 mio. kr. for ”skatteunddragelse”. Både i sin kunst og i sine ma...

  7. Evidence For Hmgn2 Involvement in Mouse Embryo Implantation and Decidualization

    Directory of Open Access Journals (Sweden)

    Dang-Dang Li

    2017-12-01

    Full Text Available Background/Aims: Hmgn2 is involved in regulating embryonic development, but its physiological function during embryo implantation and decidualization remains unknown. Methods: In situ hybridization, real-time PCR, RNA interference, gene overexpression and MTS assay were used to examine the expression of Hmgn2 in mouse uterus during the pre-implantation period and explore its function and regulatory mechanisms in epithelial adhesion junction and stromal cell proliferation and differentiation. Results: Hmgn2 was primarily accumulated in uterine luminal epithelia on day 4 of pregnancy and subluminal stromal cells around the implanting blastocyst at implantation sites on day 5. Similar results were observed during delayed implantation and activation. Meanwhile, Hmgn2 expression was visualized in the decidua. In uterine epithelial cells, silencing of Hmgn2 by specific siRNA reduced the expression of adhesion molecules Cdh1, Cdh2 and Ctnnb1 and enhanced the expression of Muc1, whereas constitutive activation of Hmgn2 exhibited the opposite effects, suggesting a role for Hmgn2 in attachment reaction during embryo implantation. Estrogen stimulated the expression of Hmgn2 in uterine epithelia, but the stimulation was abrogated by ER antagonist ICI 182,780. Further analysis evidenced that attenuation of Hmgn2 might eliminate the regulation of estrogen on the expression of Cdh1, Cdh2 and Ctnnb1. In uterine stromal cells, progesterone induced the accumulation of Hmgn2 which advanced the expression of Prl8a2 and Prl3c1, two well-known differentiation markers for decidualization, but did not affect the proliferation of stromal cells. Knockdown of Hmgn2 blocked the progesterone-induced differentiation of uterine stromal cells. Moreover, Hmgn2 might serve as an intermediate to mediate the regulation of progesterone on Hand2. Conclusion: Hmgn2 may play an important role during embryo implantation and decidualization.

  8. Biocompatibility property of 100% strontium-substituted SiO2 -Al2 O3 -P2 O5 -CaO-CaF2 glass ceramics over 26 weeks implantation in rabbit model: Histology and micro-Computed Tomography analysis.

    Science.gov (United States)

    Basu, Bikramjit; Sabareeswaran, A; Shenoy, S J

    2015-08-01

    One of the desired properties for any new biomaterial composition is its long-term stability in a suitable animal model and such property cannot be appropriately assessed by performing short-term implantation studies. While hydroxyapatite (HA) or bioglass coated metallic biomaterials are being investigated for in vivo biocompatibility properties, such study is not extensively being pursued for bulk glass ceramics. In view of their inherent brittle nature, the implant stability as well as impact of long-term release of metallic ions on bone regeneration have been a major concern. In this perspective, the present article reports the results of the in vivo implantation experiments carried out using 100% strontium (Sr)-substituted glass ceramics with the nominal composition of 4.5 SiO2 -3Al2 O3 -1.5P2 O5 -3SrO-2SrF2 for 26 weeks in cylindrical bone defects in rabbit model. The combination of histological and micro-computed tomography analysis provided a qualitative and quantitative understanding of the bone regeneration around the glass ceramic implants in comparison to the highly bioactive HA bioglass implants (control). The sequential polychrome labeling of bone during in vivo osseointegration using three fluorochromes followed by fluorescence microscopy observation confirmed homogeneous bone formation around the test implants. The results of the present study unequivocally confirm the long-term implant stability as well as osteoconductive property of 100% Sr-substituted glass ceramics, which is comparable to that of a known bioactive implant, that is, HA-based bioglass. © 2014 Wiley Periodicals, Inc.

  9. Naltrexone ER/Bupropion ER: A Review in Obesity Management.

    Science.gov (United States)

    Greig, Sarah L; Keating, Gillian M

    2015-07-01

    Oral naltrexone extended-release/bupropion extended-release (naltrexone ER/bupropion ER; Contrave(®), Mysimba(™)) is available as an adjunct to a reduced-calorie diet and increased physical activity in adults with an initial body mass index (BMI) of ≥ 30 kg/m(2) (i.e. obese) or a BMI of ≥ 27 kg/m(2) (i.e. overweight) in the presence of at least one bodyweight-related comorbidity, such as type 2 diabetes mellitus, hypertension or dyslipidaemia. In 56-week phase III trials in these patient populations, oral naltrexone ER/bupropion ER 32/360 mg/day was significantly more effective than placebo with regard to percentage bodyweight reductions from baseline and the proportion of patients who achieved bodyweight reductions of ≥ 5 and ≥ 10%. Significantly greater improvements in several cardiometabolic risk factors were also observed with naltrexone ER/bupropion ER versus placebo, as well as greater improvements in glycated haemoglobin levels in obese or overweight adults with type 2 diabetes. Naltrexone ER/bupropion ER was generally well tolerated in phase III trials, with nausea being the most common adverse event. Thus, naltrexone ER/bupropion ER 32/360 mg/day as an adjunct to a reduced-calorie diet and increased physical activity, is an effective and well tolerated option for chronic bodyweight management in obese adults or overweight adults with at least one bodyweight-related comorbidity.

  10. Hvem er gal?

    DEFF Research Database (Denmark)

    Løvstad, Charlotte Vange

    2017-01-01

    Fem medarbejdere har gennem de sidste fire år mistet livet, mens de har passet deres arbejde på et socialpsykiatrisk botilbud. Artiklen behandler tematikken sikkerhed og pædagogik og hvordan man kan understøtte borgerens bæredygtige udvikling samtidigt med at der også tages vare på personalets si...

  11. Rouw mag er zijn

    Directory of Open Access Journals (Sweden)

    Marlieke Moors

    2015-12-01

    Full Text Available ABSTRACTGrieving is allowedGrief is a human experience. Every form of loss shapes you into the human being you are today. Contrary to what earlier, unproven grief models postulate, grief does not have an end point. That is, bereavement does not have to be completely processed, but it should be integrated into someone’s life. The outdated grief models were often interpreted and used in a normative way, which led to a normative standard model. This portraits the belief that every mourner would experience similar symptoms and would go through a fixed pattern of phases. However, the updated vision emphasizes the individual and unique process of coping with loss: norms concerning grief should be banned. By means of literature research, interviews with professionals and personal experiences, it became clear that finding an equilibrium between restoration-orientated and loss-orientated coping styles is most beneficial. An important aspect in finding this balance is meaningfulness. Furthermore, the ability to bear a loss and to adapt accordingly are important components. Lastly, attaching significance to a loss is a constructive way of integrating the loss into one’s life. The death of a loved one should therefore not be forgotten or tucked away. After all, grief is the price we pay for love. SAMENVATTINGRouw mag er zijnRouw is een menselijke ervaring en elk verlies vormt je als mens. Rouw heeft, in tegenstelling tot wat de verouderde, niet bewezen rouwmodellen beweren, geen eindpunt. Verlies hoeft namelijk niet verwerkt te worden, maar moet juist geïntegreerd worden in iemands leven. De verouderde rouwmodellen zijn vaak normatief opgevat en toegepast, waaruit een normatief standaardmodel is ontstaan. Daarbij werd gedacht dat elke rouwende dezelfde symptomen zou vertonen en het rouwproces volgens vaste fasen zou verlopen. Binnen de vernieuwde visie wordt er juist van uitgegaan dat elk individu een unieke manier van reageren op rouw heeft. Er zou

  12. Implantable contraception.

    Science.gov (United States)

    Meckstroth, K R; Darney, P D

    2000-12-01

    Although levonorgestrel contraceptive implants have been available for over 15 years, innovations have only recently led to a wider choice. These new implants offer easier insertion and removal and other advantages depending on the type of progestin. Implants prevent pregnancy by several mechanisms, including inhibition of ovulation and luteal function and alteration of cervical mucus and the endometrium. The high efficacy and ease of maintenance make implants an ideal contraceptive for many women, including adolescents, a population that uses implants infrequently but reports high satisfaction. Implants are appropriate for women who are breastfeeding, who have contraindications to estrogen, or who have diseases such as diabetes, hypertension, sickle cell anemia, or an HIV infection because implants have few metabolic or hematologic effects. Long-term use has not been associated with a decrease in BMD and generally leads to increased blood levels and iron stores. Women who wish to space their pregnancies appreciate the nearly immediate onset of action with insertion and the rapid termination of all effects with removal. All types of implants lead to menstrual changes and other side effects in some women. Adverse effects that occur in implant users more than the general population include headaches and acne. Women must be thoroughly counseled regarding the potential for menstrual alteration, side effects, and sexually transmitted infections if they do not use condoms. Despite their initial high cost, implants are a cost-effective method over several years, even when discontinued before the life of the implant.

  13. Alt er ændret. Intet er afklaret

    DEFF Research Database (Denmark)

    Helmersen, Ole

    2017-01-01

    Brexit kan redefinere landets internationale rolle lige så meget som Suezkrisen. Men 15 måneder efter afstemningen er der stadig ingen svar.......Brexit kan redefinere landets internationale rolle lige så meget som Suezkrisen. Men 15 måneder efter afstemningen er der stadig ingen svar....

  14. Dental Implant Surgery

    Science.gov (United States)

    ... to find out more. Dental Implant Surgery Dental Implant Surgery Dental implant surgery is, of course, surgery, and is ... to find out more. Dental Implant Surgery Dental Implant Surgery Dental implant surgery is, of course, surgery, and is ...

  15. Er talesprog en medieteknologi?

    DEFF Research Database (Denmark)

    Tække, Jesper

    2013-01-01

    for den menneskelige udfoldelse. Til at løse denne opgave vil jeg trække på den tyske sociolog og systemteoretiker Niklas Luhmann der også udmærker sig som medieteoretiker (Tække 2006a). Luhmann har ikke selv direkte redegjort for sprog som teknologi, men da han både har udviklet et brugbart...... motiver og viden, må give mening til hvad, der meddeles og selektere en forståelse (Luhmann 2000a). Formålet med og berettigelsen for medieteori er ud fra Marshall McLuhans (1967) devise, om at the medium is the message, at sammenligne, hvad det betyder for menneske og samfund, at der kommunikeres i ét...

  16. Den rige personlighed er livsduelig

    DEFF Research Database (Denmark)

    Holm, Claus

    2015-01-01

    For omtrent 160 år siden formulerede Karl Marx forestillingen om en rig individualitet som det kommunistiske samfunds individideal. I dag får forestillingen relevans. Lyder det lidt besynderligt, er det ikke mærkeligt. For de fleste af os går næppe rundt og tror, at vi er lige på trapperne til...

  17. Kollegaerne er den nye chef

    DEFF Research Database (Denmark)

    Fugl, Marie

    2008-01-01

    Den tid, hvor chefen var den, der delte skideballer ud, er slut. Rollen som 'bad cop' er overtaget af kollegateamet, der med hård hånd sørger for, at den enkelte yder sin del. Udgivelsesdato: November...

  18. RNA er jo bare matematik!

    DEFF Research Database (Denmark)

    Blaavand, Jakob Lindblad

    2011-01-01

    Hvordan kan man kurere sygdomme med matematiske geometriske strukturer? Det kan man i princippet, hvis de geometriske figurer er RNA-molekyler, og sygdommen skyldes syge gener.......Hvordan kan man kurere sygdomme med matematiske geometriske strukturer? Det kan man i princippet, hvis de geometriske figurer er RNA-molekyler, og sygdommen skyldes syge gener....

  19. Fraflytning er ikke en naturlov

    DEFF Research Database (Denmark)

    Nørgaard, Helle

    2015-01-01

    DEBAT: Der er brug for en erkendelse af, at det ikke er en naturlov, at folk vil flytte til byerne. Forskning viser, at børnefamilier finder tryghed og ideelle rammer for familielivet på landet. Det skriver Helle Nørgaard, seniorforsker, ph.d., Statens Byggeforskningsinstitut, Aalborg Universitet....

  20. Er danske virksomheder mindre innovative?

    DEFF Research Database (Denmark)

    Madsen, Erik Strøjer; Smith, Valdemar; Nielsen, Anders Østergaard

    2000-01-01

    Med jævne mellemrum er det blevet fremhævet i de skrevne medier, at danske virksomheder er mindre patentaktive, og at de teknologisk taber terræn i forhold til deres udenlandske konkurrenter. Nærværende artikel belyser udviklingen i såvel patentaktiviteten som de anvendte ressourcer til forskning...

  1. Humor er en alvorlig sag

    DEFF Research Database (Denmark)

    Søltoft, Pia

    2016-01-01

    I modsætning til ironi er humor for Kierkegaard fællesskabsgivende – ironikeren hævder sig selv, men humoristen har sympati med den, man ler med. Humor er hos Kierkegaard udtryk for, at humoristen forliger sig med tilværelsen og dens luner, og dermed grænser humoren hos Kierkegaard op til det...

  2. Propagation of misfit dislocations from buffer/Si interface into Si

    Science.gov (United States)

    Liliental-Weber, Zuzanna [El Sobrante, CA; Maltez, Rogerio Luis [Porto Alegre, BR; Morkoc, Hadis [Richmond, VA; Xie, Jinqiao [Raleigh, VA

    2011-08-30

    Misfit dislocations are redirected from the buffer/Si interface and propagated to the Si substrate due to the formation of bubbles in the substrate. The buffer layer growth process is generally a thermal process that also accomplishes annealing of the Si substrate so that bubbles of the implanted ion species are formed in the Si at an appropriate distance from the buffer/Si interface so that the bubbles will not migrate to the Si surface during annealing, but are close enough to the interface so that a strain field around the bubbles will be sensed by dislocations at the buffer/Si interface and dislocations are attracted by the strain field caused by the bubbles and move into the Si substrate instead of into the buffer epi-layer. Fabrication of improved integrated devices based on GaN and Si, such as continuous wave (CW) lasers and light emitting diodes, at reduced cost is thereby enabled.

  3. Renovering er en vigtig arkitektonisk opgave

    DEFF Research Database (Denmark)

    Bech-Danielsen, Claus

    2008-01-01

    Renovering af almene boliger er et stort og voksende arbejdsfelt. Der er tale om en vigtig arkitektonisk opgave, der er både spændende og fagligt udfordrende. Udgivelsesdato: juni......Renovering af almene boliger er et stort og voksende arbejdsfelt. Der er tale om en vigtig arkitektonisk opgave, der er både spændende og fagligt udfordrende. Udgivelsesdato: juni...

  4. Implant contraception.

    Science.gov (United States)

    Meckstroth, K R; Darney, P D

    2001-12-01

    The experience of 6 million Norplant users has led to several more advanced implants. Implanon is a single-rod implant system containing a low androgenic progestin and requires 1 to 2 minutes for insertion and removal. Like other implants, Implanon prevents pregnancy by changing the character of the cervical mucus and interfering with luteal function. Unlike Norplant, though, Implanon is designed to prevent ovulation for the full duration of use. Implant contraception has several advantages over other types of contraception including high efficacy, minimal required maintenance, absence of estrogen, and rapid return of fertility after discontinuation. Implants can be a good choice for adolescents; women with hypertension, diabetes, anemia, endometriosis, or other medical problems; and women who are breast-feeding. Irregular bleeding is the most common adverse effect of implants and can be treated with several medication regimens. Preinsertion counseling, however, is the most important factor in ensuring satisfaction with implants. Unfortunately, no implant system is currently available in the United States since August 2000, but Implanon is expected to reach the U.S. market within the next 2 years.

  5. Min mentor er min voksenven

    DEFF Research Database (Denmark)

    Kaiser, Birte

    2009-01-01

    En artikel i bogen: 6 belysninger af vejledning, brydninger, forståelser & praksis. Artiklen er et sammendrag af en diskursanalyse fra 2008 fra projetrapporten: Ind under huden, www.vejledning.net...

  6. About Implantable Contraception

    Science.gov (United States)

    ... Helping Your Child Deal With Death About Implantable Contraception KidsHealth > For Parents > About Implantable Contraception Print A ... How Much Does It Cost? What Is Implantable Contraception? Implantable contraception (often called the birth control implant) ...

  7. Photoluminescence enhancement through silicon implantation on SRO-LPCVD films

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Sanchez, A., E-mail: amorales@inaoep.mx [INAOE, Electronics Department, Apartado 51, Puebla 72000 (Mexico); Leyva, K.M.; Aceves, M. [INAOE, Electronics Department, Apartado 51, Puebla 72000 (Mexico); Barreto, J.; Dominguez, C. [Instituto de Microelectronica de Barcelona, IMB-CNM (CSIC), Barcelona (Spain); Luna-Lopez, J.A.; Carrillo, J. [CIDS-BUAP, Apdo. 1651, Puebla 72000 (Mexico); Pedraza, J. [INAOE, Electronics Department, Apartado 51, Puebla 72000 (Mexico)

    2010-10-25

    Photoluminescence (PL) properties of thin and thick silicon-rich oxide (SRO) and silicon implanted SRO (SI-SRO) films with different silicon excess fabricated by low pressure chemical vapor deposition (LPCVD) were studied. The effects of the annealing temperature and silicon implantation on the PL were also studied. Maximum luminescence intensity was observed with an annealing temperature of 1150 and 1100 deg. C for thin and thick SRO films, respectively. The PL intensity is strongly enhanced when SRO films are implanted with silicon, especially for thin SRO films. Thin SI-SRO films emit up to six times more than non-implanted films, meanwhile the PL in thick SI-SRO films is only improved less than two times. Therefore, thin SI-SRO films are an interesting alternative for applications such as the fabrication of efficient Si-nps based LEDs.

  8. Forenklingens fire F'er

    DEFF Research Database (Denmark)

    Bentzen, Tina Øllgaard

    2017-01-01

    At fjerne styring er det, man ofte forbinder med afbureaukratisering, men det er ikke tilstrækkeligt, når man vil gå fra flotte ambitioner til en styring, som reelt opleves enklere. For at forenkle må man også forandre, forankre og fastholde styring, og det må ske i et samspil mellem de aktører, ...

  9. Structure, optical properties and thermal stability of HfErO films deposited by simultaneous RF and VHF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.Y. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Nanjing University of Posts and Telecommunications, School of Tongda, Nanjing (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); He, H.J.; Zhang, Z.; Jin, C.G.; Yang, Y.; Wang, Y.Y.; Ye, C. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Zhuge, L.J. [Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Soochow University, Analysis and Testing Center, Suzhou (China); Wu, X.M. [Soochow University, College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Suzhou (China); Soochow University, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Suzhou (China); Chinese Academy of Sciences, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Shanghai (China)

    2015-01-23

    HfErO films are deposited on Si substrates by simultaneous radio frequency (RF) and very high frequency (VHF) magnetron sputtering technique. The content of the doped ingredient of Er and the body composition of HfO{sub x} are, respectively, controlled through the VHF and RF powers. Low content of Er doping in the HfErO films can be achieved, because the VHF source of 27.12 MHz has higher ion energy and lower ion flux than the RF source resulting in low sputtering rate in the magnetron sputtering system. The structure, optical properties and thermal stability of the HfErO films are investigated in this work. Results show that the doped content of Er is independently controlled by the VHF power. The oxygen vacancies are created by the Er incorporation. The hafnium in the HfErO films forms mixed valence of Hf{sup 2+} and Hf{sup 4+}. The HfErO films are composed with the structures of HfO{sub 2}, HfO and ErO{sub x}, which can be optimized through the VHF power. At high VHF power, the Hf-Er-O bonds are formed, which demonstrates that the Er atoms are doped into the lattice of HfO{sub 2} in the HfErO films. The HfErO films have bad thermal stability as the crystallization temperature decreases from 900 to 800 C. After thermal annealing, cubic phase of HfO{sub 2} are stabilized, which is ascribed to the oxygen vacancies creation by the Er incorporation. The optical properties such as the refractive index and the optical band gap of the HfErO films are optimized by the VHF power. (orig.)

  10. Effects of antimony (Sb) on electron trapping near SiO{sub 2}/4H-SiC interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mooney, P. M.; Jiang, Zenan; Basile, A. F. [Physics Department, Simon Fraser University, Burnaby, British Columbia V5A 1S6 (Canada); Zheng, Yongju; Dhar, Sarit [Physics Department, Auburn University, Auburn, Alabama 36849 (United States)

    2016-07-21

    To investigate the mechanism by which Sb at the SiO{sub 2}/SiC interface improves the channel mobility of 4H-SiC MOSFETs, 1 MHz capacitance measurements and constant capacitance deep level transient spectroscopy (CCDLTS) measurements were performed on Sb-implanted 4H-SiC MOS capacitors. The measurements reveal a significant concentration of Sb donors near the SiO{sub 2}/SiC interface. Two Sb donor related CCDLTS peaks corresponding to shallow energy levels in SiC were observed close to the SiO{sub 2}/SiC interface. Furthermore, CCDLTS measurements show that the same type of near-interface traps found in conventional dry oxide or NO-annealed capacitors are present in the Sb implanted samples. These are O1 traps, suggested to be carbon dimers substituted for O dimers in SiO{sub 2}, and O2 traps, suggested to be interstitial Si in SiO{sub 2}. However, electron trapping is reduced by a factor of ∼2 in Sb-implanted samples compared with samples with no Sb, primarily at energy levels within 0.2 eV of the SiC conduction band edge. This trap passivation effect is relatively small compared with the Sb-induced counter-doping effect on the MOSFET channel surface, which results in improved channel transport.

  11. Reversing the temperature dependence of the sensitized Er3+ luminescence intensity

    Science.gov (United States)

    Lenz, F.; Hryciw, A.; DeCorby, R.; Meldrum, A.

    2009-08-01

    The temperature-induced quenching of the Er3+ luminescence is a significant problem in silicon-based materials systems ultimately designed for room-temperature applications. Here, we show that amorphous silicon-rich oxide, moderately annealed in order to avoid growth of Si nanocrystals, exhibits a reversed temperature dependence in which the integrated Er3+ luminescence increases in intensity upon heating from 77 up to 300 K. This behavior is attributed to a unique spectrum of interacting defects that efficiently sensitize the Er3+ levels, even in the absence of nanocrystals. The effect could have ramifications in fiber-optic emitters or amplifiers to be operated at noncryogenic temperatures.

  12. Mitofusin-2 knockdown increases ER-mitochondria contact and decreases amyloid β-peptide production.

    Science.gov (United States)

    Leal, Nuno Santos; Schreiner, Bernadette; Pinho, Catarina Moreira; Filadi, Riccardo; Wiehager, Birgitta; Karlström, Helena; Pizzo, Paola; Ankarcrona, Maria

    2016-09-01

    Mitochondria are physically and biochemically in contact with other organelles including the endoplasmic reticulum (ER). Such contacts are formed between mitochondria-associated ER membranes (MAM), specialized subregions of ER, and the outer mitochondrial membrane (OMM). We have previously shown increased expression of MAM-associated proteins and enhanced ER to mitochondria Ca(2+) transfer from ER to mitochondria in Alzheimer's disease (AD) and amyloid β-peptide (Aβ)-related neuronal models. Here, we report that siRNA knockdown of mitofusin-2 (Mfn2), a protein that is involved in the tethering of ER and mitochondria, leads to increased contact between the two organelles. Cells depleted in Mfn2 showed increased Ca(2+) transfer from ER to mitchondria and longer stretches of ER forming contacts with OMM. Interestingly, increased contact resulted in decreased concentrations of intra- and extracellular Aβ40 and Aβ42 . Analysis of γ-secretase protein expression, maturation and activity revealed that the low Aβ concentrations were a result of impaired γ-secretase complex function. Amyloid-β precursor protein (APP), β-site APP-cleaving enzyme 1 and neprilysin expression as well as neprilysin activity were not affected by Mfn2 siRNA treatment. In summary, our data shows that modulation of ER-mitochondria contact affects γ-secretase activity and Aβ generation. Increased ER-mitochondria contact results in lower γ-secretase activity suggesting a new mechanism by which Aβ generation can be controlled. © 2016 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  13. Penile Implants

    Science.gov (United States)

    ... men with erectile dysfunction (ED) to get an erection. Penile implants are typically recommended after other treatments for ... the scrotum, and two inflatable cylinders inside the penis. To achieve an erection, you pump the fluid from the reservoir into ...

  14. Cochlear Implants

    Science.gov (United States)

    ... the skin. An implant does not restore normal hearing. It can help a person understand speech. Children and adults can benefit from them. National Institute on Deafness and Other Communication Disorders

  15. Screening af kulturmiljøer

    DEFF Research Database (Denmark)

    2017-01-01

    Arkitektskolen Aarhus sætter fokus på kulturmiljøer i Danmarks yderområder. Screening af Kulturmiljøer (SAK) er et redskab til at vurdere kulturmiljøer ud fra aflæselige parametre, så kulturarvens værdier, egenskaber og udviklingspotentialer bliver synlige. Formålet er at skabe nye muligheder og...

  16. Cochlear implant by adult

    OpenAIRE

    Kratochvílová, Tereza

    2011-01-01

    Bachelor thesis "The cochlear implant in an adult deaf" deals primarily with the cochlear implant. The most extensive part of the thesis talks about this topic, which also talks about the development and design of cochlear implants, explains the difference between cochlear implantation and tribal implantation and describes operation of implant and the subsequent setting of the implant. This section is also dedicated to binaural cochlear implantation, myths of cochlear implants and problems wh...

  17. A novel variant of ER-alpha, ER-alpha36 mediates testosterone-stimulated ERK and Akt activation in endometrial cancer Hec1A cells

    Directory of Open Access Journals (Sweden)

    Wang Zhao-Yi

    2009-09-01

    Full Text Available Abstract Background Endometrial cancer is one of the most common gynecologic malignancies and its incidence has recently increased. Experimental and epidemiological data support that testosterone plays an important role in the pathogenesis of endometrial cancer, but the underlying mechanism has not been fully understood. Recently, we identified and cloned a variant of estrogen receptor (ER alpha, ER-alpha36. The aim of the present study was to investigate the role of ER-alpha36 in testosterone carcinogenesis. Methods The cellular localization of ER-alpha36 was determined by immunofluorescence. Hec1A endometrial cancer cells (Hec1A/V and Hec1A cells with siRNA knockdown of ER-alpha36 (Hec1A/RNAi were treated with testosterone, ERK and Akt phosphorylation was assessed by Western blot analysis. Furthermore, the kinase inhibitors U0126 and LY294002 and the aromatase inhibitor letrozole were used to elucidate the pathway underlying testosterone-induced activities. Results Immunofluorescence shows that ER-alpha36 was localized on the plasma membrane of the both ER-alpha- and androgen receptor-negative endometrial cancer Hec1A cells. Testosterone induced ERK and Akt phosphorylation, which could be abrogated by ER-alpha 36 shRNA knockdown or the kinase inhibitors, U0126 and LY294002, and the aromatase inhibitor letrozole. Conclusion Testosterone induces ERK and Akt phosphorylation via the membrane-initiated signaling pathways mediated by ER-alpha36, suggesting a possible involvement of ER-alpha 36 in testosterone carcinogenesis.

  18. Current concepts in the use of lasers in periodontal and implant dentistry

    OpenAIRE

    Romanos, Georgios

    2015-01-01

    Lasers have various periodontal applications including calculus removal (Er: YAG, Er, Cr: YSGG lasers); soft tissue excision, incision and ablation; decontamination of root and implant surfaces; biostimulation; bacteria reduction; and osseous surgery. This paper reviews some of the major opportunities for using lasers in periodontal and implant specialty practices. The literature relating to the use of lasers for removal of the pocket epithelium, root conditioning, bacterial reduction and dec...

  19. Borgeren er tilskuer og bruger

    DEFF Research Database (Denmark)

    Thyssen, Ole

    2013-01-01

    Siden den politiske elite blev afhængig af borgernes stemmer, har det været en fast bestanddel i enhver valgkamp, at politikere giver løfter om et bedre liv - bedre arbejde og mere velfærd. Resultatet er en kravsinflation, hvor den ene part lover, og den anden part kræver mere velfærd. Nøk for nø...... og uden en samlet plan er velfærden og staten blevet slået af elefantiasis....

  20. Foregribende sorg er ikke forebyggende

    DEFF Research Database (Denmark)

    Nielsen, Mette Kjærgaard; Thomsen, Kia Toft; Jensen, Anders Bonde

    2017-01-01

    Baggrund: Betydningen af pårørendes sorgsymptomer før tid, tidligere kaldet foregribende sorg, er uklar. Materiale og metode: En landsdækkende spørgeskemaundersøgelse af 3635 pårørende til patienter med terminaltilskud i 2012. Resultater: Mange symptomer på sorg før død havde sammenhæng med kompl...... kompliceret sorgreaktion efter dødsfaldet samt faktorer i det palliative forløb. Fortolkning: Sorg før dødsfaldet har sammenhæng med forværret sorgreaktion; foregribende sorg er misvisende....

  1. Kemalismen er truet i Tyrkiet

    DEFF Research Database (Denmark)

    Østergaard, Uffe

    2016-01-01

    Historisk set. Arven efter det sekulære Tyrkiets landsfader, Mustafa Kemal Atatürk, er truet i det kulturopgør, som præsident Erdogan har iværksat efter det nylige kupforsøg.......Historisk set. Arven efter det sekulære Tyrkiets landsfader, Mustafa Kemal Atatürk, er truet i det kulturopgør, som præsident Erdogan har iværksat efter det nylige kupforsøg....

  2. The role of ER stress response on ionizing radiation-induced apoptosis in intestinal epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Sang; Kim, Kwang Seok; Woo, Sang Keun; Lee, Yong Jin; Jeong, Jae Hoon; Lee, Yoon Jin; Kang, Seong Man; Lim, Young Bin [Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2014-04-15

    Apoptosis in the intestinal epithelium is the primary pathologic factor that initiates radiation-induced intestinal injury. However, mechanism involved in ionizing radiation (IR)-induced apoptosis in the intestinal epithelium is not clearly understood. The endoplasmic reticulum (ER) stress is triggered by perturbation of the ER functions, leading to the activation of the unfolded protein response (UPR), an adaptive signaling cascade aimed at restoring ER homeostasis by facilitating the degradation of misfolded proteins and expanding the protein folding capacity of the cell. Recently, IR has also been shown to induce ER stress, thereby activating the UPR signaling pathway in intestinal epithelial cells. In this study, we report the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhance IR-induced caspase3 activation. Knockdown of xbp1 or atf6 with siRNA leads to inhibition of IR-induced caspase3 activation. Taken together, our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Our findings could contribute to the development of new strategies based on modulating ER stress responses to prevent IR-induced intestinal injury.

  3. Optical amplification and electroluminescence at 1.54 μm in Er-doped zinc silicate germanate on silicon

    Science.gov (United States)

    Baker, C. C.; Heikenfeld, J.; Yu, Z.; Steckl, A. J.

    2004-03-01

    Optical amplification and electroluminescence at 1.5 μm is reported in Er-doped Zn2Si0.5Ge0.5O4 (ZSG:Er) on silicon. ZSG:Er films were deposited by rf sputtering from a composite target in Ar/O2 mixtures. Channel waveguides were fabricated by plasma etching with Cl/Ar. The refractive index of ZSG:Er was found to be 1.75 at 1.54 μm. Signal enhancement greater than 13 dB and an internal gain of ˜2 dB have been achieved by optically pumping a 4.7 cm ZSG:Er amplifier. Electroluminescence at 1.5 μm was achieved using an ac device structure with a ZSG:Er central layer and upper and lower dielectric layers.

  4. Ro på: Solen er stille

    DEFF Research Database (Denmark)

    Pedersen, Jens Olaf Pepke

    2008-01-01

    Efter at Solen har øget sin aktivitet gennem 100 år, er der nu tydelige tegn på, at den er ved at falde til ro. Er den ved at gå i dvale? Og vil det i så fald udløse en global kuldeperiode?......Efter at Solen har øget sin aktivitet gennem 100 år, er der nu tydelige tegn på, at den er ved at falde til ro. Er den ved at gå i dvale? Og vil det i så fald udløse en global kuldeperiode?...

  5. Den sproglige leg er super fly

    DEFF Research Database (Denmark)

    Just, Sine Nørholm

    2013-01-01

    Man kan rappe om alt. I hvert fald hvis man er Marvelous Mosell. I spændingsfeltet mellem fiktion og virkelighed skaber Mosell sin persona i et forjættende 80' er-univers der på en og samme tid er vildt overdrevet og helt autentisk.......Man kan rappe om alt. I hvert fald hvis man er Marvelous Mosell. I spændingsfeltet mellem fiktion og virkelighed skaber Mosell sin persona i et forjættende 80' er-univers der på en og samme tid er vildt overdrevet og helt autentisk....

  6. Vidensamfundet - det er sund fornuft

    DEFF Research Database (Denmark)

    Pedersen, Esther Oluffa

    2008-01-01

    meget kort tid har opnået at blive udmøntet som dansk lov. Sigtet med artiklen er (1) at give en kritisk kommentar til den definition af viden, som ligger til grund for sloganet 'fra tanke til faktura'. Rapporterne analyseres for at belyse den ideologiske baggrund, der ligger bag de strategisk...

  7. N-ov-emb-er

    Indian Academy of Sciences (India)

    " to. Andrew Z Fire - Stanford University School of Medicine Stanford, CA, USA. Craig C Mello - University of Massachusetts Medical School Worcester, MA, USA. -96----------------------------~~--------R-ES-O-N-A-N-C-E--1 -N-ov-e-m-b-er--2-oo-6.

  8. Different strain relaxation mechanisms in strained Si/Si sub 1 sub - sub x Ge sub x /Si heterostructures by high dose B sup + and BF sub 2 sup + doping

    CERN Document Server

    Chen, C C; Zhang, S L; Zhu, D Z; Vantomme, A

    2002-01-01

    Strained Si/Si sub 0 sub . sub 8 Ge sub 0 sub . sub 2 /Si heterostructures are implanted at room temperature with 7.5 keV B sup + and 33 keV BF sub 2 sup + ions to a high dose of 2x10 sup 1 sup 5 ions/cm sup 2 , respectively. The samples are subsequently subjected to three-step anneals (spacer anneal, oxidation anneal and rapid thermal anneal), which are used to simulate a real fabrication process of SiGe-based MOSFET devices. The damage induced by implantation and its recovery are characterized by 2 MeV sup 4 He sup + RBS/channeling spectrometry. A damage layer on the surface is induced by B sup + implantation, but BF sup + sub 2 ion implantation amorphizes the surface of Si/Si sub 0 sub . sub 8 Ge sub 0 sub . sub 2 /Si heterostructure. Channeling angular scans along the axial direction demonstrate that the strain stored in the SiGe layer could be nearly completely retained for the B sup + implanted and subsequently annealed sample. However, the strain in the BF sub 2 sup + implanted/annealed SiGe layer has...

  9. Shallow boron-doped layer formation by boron diffusion from poly-Si through thin SiO2

    Science.gov (United States)

    Miyake, Masayasu

    1994-06-01

    This paper discusses boron doping using metal oxide semiconductor structure (poly-Si/SiO2/Si). The thin SiO2 layer acts as a stopper to poly-Si removal after doping. When boron implantation is used for poly-Si doping, shallow boron-doped layers suitable for base application can be formed by wet O2-ambient drive-in. When BF2 implantation is used, shallow boron-doped layers can be formed even by N2-ambient drive-in. The surface boron concentration of boron-doped layers increases with dose and saturates, since boron concentration in poly-Si in the region near the interface with SiO2 also increases with dose and saturates. An estimate of the boron diffusion coefficient in SiO2, D(sub ox), shows that it increases by about one order of magnitude both for boron implantation with subsequent wet O2-ambient drive-in and for BF2 implantation with subsequent N2-ambient drive-in.

  10. Bacterial adhesion on ion-implanted stainless steel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Q. [Department of Mechanical Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom)]. E-mail: q.zhao@dundee.ac.uk; Liu, Y. [Department of Mechanical Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom); Wang, C. [Department of Mechanical Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom); Wang, S. [Department of Mechanical Engineering, University of Dundee, Dundee DD1 4HN (United Kingdom); Peng, N. [Surrey Ion Beam Centre, University of Surrey, Surrey GU2 7XH (United Kingdom); Jeynes, C. [Surrey Ion Beam Centre, University of Surrey, Surrey GU2 7XH (United Kingdom)

    2007-08-31

    Stainless steel disks were implanted with N{sup +}, O{sup +} and SiF{sub 3} {sup +}, respectively at the Surrey Ion Beam Centre. The surface properties of the implanted surfaces were analyzed, including surface chemical composition, surface topography, surface roughness and surface free energy. Bacterial adhesion of Pseudomonas aeruginosa, Staphylococcus epidermidis and Staphylococcus aureus, which frequently cause medical device-associated infections was evaluated under static condition and laminar flow condition. The effect of contact time, growth media and surface properties of the ion-implanted steels on bacterial adhesion was investigated. The experimental results showed that SiF{sub 3} {sup +}-implanted stainless steel performed much better than N{sup +}-implanted steel, O{sup +}-implanted steel and untreated stainless steel control on reducing bacterial attachment under identical experimental conditions.

  11. Antimicrobial effects of three different treatment modalities on dental implant surfaces.

    Science.gov (United States)

    Larsen, Olav Inge; Enersen, Morten; Kristoffersen, Anne Karin; Wennerberg, Ann; Bunæs, Dagmar F; Lie, Stein Atle; Leknes, Knut N

    2017-10-03

    Resolution of peri-implant inflammation and re-osseointegration of peri-implantitis affected dental implants seem to be dependent on bacterial decontamination. The aims of the this study were to evaluate the antimicrobial effects of three different instrumentations on a micro-textured dental implant surface contaminated with an avirulent or a virulent Porphyromonas gingivalis strain and to determine alterations to the implant surface following instrumentation. Forty-five dental implants (Straumann SLA) were allocated to three treatment groups: Er:YAG laser, chitosan brush, and titanium curette (10 implants each), a positive (10 implants) and a negative (five implants) control. Each treatment group and the positive control were split into subgroups of five implants subsequently contaminated with either the avirulent or virulent P. gingivalis strain. The antimicrobial effect of instrumentation was evaluated using checkerboard DNA-DNA hybridization. Implant surface alterations were determined using a light interferometer. Instrumentation significantly reduced the number of attached P. gingivalis (pimplant surface micro-texture. Neither the Er:YAG laser nor the chitosan brush significantly altered the implant surface. The three instrumentations appear to have a similar potential to remove P. gingivalis. The titanium curette significantly altered the microstructure of the implant surface.

  12. Regular and platform switching: bone stress analysis varying implant type.

    Science.gov (United States)

    Gurgel-Juarez, Nália Cecília; de Almeida, Erika Oliveira; Rocha, Eduardo Passos; Freitas, Amílcar Chagas; Anchieta, Rodolfo Bruniera; de Vargas, Luis Carlos Merçon; Kina, Sidney; França, Fabiana Mantovani Gomes

    2012-04-01

    This study aimed to evaluate stress distribution on peri-implant bone simulating the influence of platform switching in external and internal hexagon implants using three-dimensional finite element analysis. Four mathematical models of a central incisor supported by an implant were created: External Regular model (ER) with 5.0 mm × 11.5 mm external hexagon implant and 5.0 mm abutment (0% abutment shifting), Internal Regular model (IR) with 4.5 mm × 11.5 mm internal hexagon implant and 4.5 mm abutment (0% abutment shifting), External Switching model (ES) with 5.0 mm × 11.5 mm external hexagon implant and 4.1 mm abutment (18% abutment shifting), and Internal Switching model (IS) with 4.5 mm × 11.5 mm internal hexagon implant and 3.8 mm abutment (15% abutment shifting). The models were created by SolidWorks software. The numerical analysis was performed using ANSYS Workbench. Oblique forces (100 N) were applied to the palatal surface of the central incisor. The maximum (σ(max)) and minimum (σ(min)) principal stress, equivalent von Mises stress (σ(vM)), and maximum principal elastic strain (ε(max)) values were evaluated for the cortical and trabecular bone. For cortical bone, the highest stress values (σ(max) and σ(vm) ) (MPa) were observed in IR (87.4 and 82.3), followed by IS (83.3 and 72.4), ER (82 and 65.1), and ES (56.7 and 51.6). For ε(max), IR showed the highest stress (5.46e-003), followed by IS (5.23e-003), ER (5.22e-003), and ES (3.67e-003). For the trabecular bone, the highest stress values (σ(max)) (MPa) were observed in ER (12.5), followed by IS (12), ES (11.9), and IR (4.95). For σ(vM), the highest stress values (MPa) were observed in IS (9.65), followed by ER (9.3), ES (8.61), and IR (5.62). For ε(max) , ER showed the highest stress (5.5e-003), followed by ES (5.43e-003), IS (3.75e-003), and IR (3.15e-003). The influence of platform switching was more evident for cortical bone than for trabecular bone, mainly for the external hexagon

  13. Evaluation of electronic states of implanted materials by molecular orbital calculation

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Jun-ichi; Kano, Shigeki [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1997-07-01

    In order to understand the effect of implanted atom in ceramics and metals on the sodium corrosion, the electronic structures of un-implanted and implanted materials were calculated using DV-X{alpha} cluster method which was one of molecular orbital calculations. The calculated materials were {beta}-Si{sub 3}N{sub 4}, {alpha}-SiC and {beta}-SiC as ceramics, and f.c.c. Fe, b.c.c. Fe and b.c.c. Nb as metals. An Fe, Mo and Hf atom for ceramics, and N atom for metals were selected as implanted atoms. Consequently, it is expected that the corrosion resistance of {beta}-Si{sub 3}N{sub 4} is improved, because the ionic bonding reduced by the implantation. When the implanted atom is occupied at interstitial site in {alpha}-SiC and {beta}-SiC, the ionic bonding reduced. Hence, there is a possibility to improve the corrosion resistance of {alpha}-SiC and {beta}-SiC. It is clear that Hf is most effective element among implanted atoms in this study. As the covalent bond between N atom and surrounding Fe atoms increased largely in f.c.c. Fe by N implantation, it was expected that the corrosion resistance of f.c.c. Fe improved in liquid sodium. (J.P.N.)

  14. The influence of cation additives on the NIR luminescence intensity of Er3+-doped borate glasses

    Science.gov (United States)

    Zhou, Yong-Liang; Zhang, Xiao-Song; Xu, Jian-Ping; Zhang, Zhong-Peng; Zhang, Gao-Feng; Wei, Feng-Wei; Li, Lan

    2012-06-01

    Er3+-doped 25BaO-(25-x)SiO2-xAl2O3-25B2O3 transparent glasses are prepared with x = 0, 12.5 and 25 by a solid-state reaction. The Er-related NIR luminescence intensity, which corresponds to the transition of 4I15/2-4I13/2, is obviously altered with different silicon/aluminum ratios. The Judd-Ofelt parameters of the Er3+ ions are adopted to explain the intensity change in the NIR fluorescence, and the Raman scattering intensity versus the amount of Al and/or Si components are discussed. The spectra of the three samples are quite similar in the peak positions, but different in intensity. The maximal phonon density of state for the samples is calculated from the Raman spectra and is correlated to the NIR luminescence efficiency.

  15. ER stress and hepatic lipid metabolism

    Directory of Open Access Journals (Sweden)

    Huiping eZhou

    2014-05-01

    Full Text Available The endoplasmic reticulum (ER is an important player in regulating protein synthesis and lipid metabolism. Perturbation of ER homeostasis, referred as ER stress, has been linked to numerous pathological conditions, such as inflammation, cardiovascular diseases and metabolic disorders. The liver plays a central role in regulating nutrient and lipid metabolism. Accumulating evidence implicates that ER stress disrupts lipid metabolism and induces hepatic lipotoxicity. Here, we review the major ER stress signaling pathways, how ER stress contributes to the dysregulation of hepatic lipid metabolism, and the potential causative mechanisms of ER stress in hepatic lipotoxicity. Understanding the role of ER stress in hepatic metabolism may lead to the identification of new therapeutic targets for metabolic diseases.

  16. Endoplasmic Reticulum (ER) Stress and Endocrine Disorders.

    Science.gov (United States)

    Ariyasu, Daisuke; Yoshida, Hiderou; Hasegawa, Yukihiro

    2017-02-11

    The endoplasmic reticulum (ER) is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the "unfolded protein response" (UPR), which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI), Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2) are discussed in this article.

  17. Endoplasmic Reticulum (ER Stress and Endocrine Disorders

    Directory of Open Access Journals (Sweden)

    Daisuke Ariyasu

    2017-02-01

    Full Text Available The endoplasmic reticulum (ER is the organelle where secretory and membrane proteins are synthesized and folded. Unfolded proteins that are retained within the ER can cause ER stress. Eukaryotic cells have a defense system called the “unfolded protein response” (UPR, which protects cells from ER stress. Cells undergo apoptosis when ER stress exceeds the capacity of the UPR, which has been revealed to cause human diseases. Although neurodegenerative diseases are well-known ER stress-related diseases, it has been discovered that endocrine diseases are also related to ER stress. In this review, we focus on ER stress-related human endocrine disorders. In addition to diabetes mellitus, which is well characterized, several relatively rare genetic disorders such as familial neurohypophyseal diabetes insipidus (FNDI, Wolfram syndrome, and isolated growth hormone deficiency type II (IGHD2 are discussed in this article.

  18. PODAAC-ERS13-IMWF0

    Data.gov (United States)

    National Aeronautics and Space Administration — The European Remote Sensing Satellite generation 2 (ERS-2) Level 3 Mean Wind Fields dataset is derived from the ERS-2 scatterometer data and is produced and...

  19. Review: implants.

    Science.gov (United States)

    Ashton, P; Blandford, D L; Pearson, P A; Jaffe, G J; Martin, D F; Nussenblatt, R B

    1994-01-01

    An implantable sustained release device has been developed to treat chronic disorders of the eye. The device, consisting of a central core of drug encased in layers of permeable and impermeable polymers, can be implanted subconjunctivally or intravitreally. This technique was used to develop a ganciclovir device which, when implanted into the vitreous, maintains therapeutic vitreous levels of drug for 8 months. Initial studies in patients with cytomegalovirus (CMV) retinitis indicate that this treatment may offer better control of the disease and fewer side effects than existing therapies. Cyclosporine A devices were prepared for the treatment of uveitis. Early data suggests that these devices maintain therapeutic levels in the vitreous for approximately 3 years. Work on efficacy and toxicity is continuing. Although clinical applications of these devices are likely to be restricted to diseases requiring chronic drug therapy, they can be used to investigate optimal delivery rates. Subconjunctivally implanted devices releasing 5-FU for 12 days maintained filters in cynomolgus monkeys for 3 months. Similar devices maintained low intraocular pressure in 75% of high risk filter patients.

  20. Er det naturlige altid godt og rigtigt?

    DEFF Research Database (Denmark)

    Gjerris, Mickey

    2017-01-01

    Beder man mennesker lukke øjnene og se ’naturen’ for sig, ender de fleste med at se bjerge, dale, vand, planter, dyr og himmel. Det, der som oftest ikke er til stede, er dem selv – mennesket.......Beder man mennesker lukke øjnene og se ’naturen’ for sig, ender de fleste med at se bjerge, dale, vand, planter, dyr og himmel. Det, der som oftest ikke er til stede, er dem selv – mennesket....

  1. Effective dopant activation by susceptor-assisted microwave annealing of low energy boron implanted and phosphorus implanted silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Vemuri, Rajitha N. P.; Alford, T. L., E-mail: TA@asu.edu [School of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); David Theodore, N. [CHD-Fab, Freescale Semiconductor Inc., 1300 N. Alma School Rd., Chandler, Arizona 85224 (United States); Lu, Wei; Lau, S. S. [Department of Electrical Engineering, University of California, San Diego, California 92093 (United States); Lanz, A. [Department of Mathematics, Norfolk State University, Norfolk, Virginia 23504 (United States)

    2013-12-28

    Rapid processing and reduced end-of-range diffusion result from susceptor-assisted microwave (MW) annealing, making this technique an efficient processing alternative for electrically activating dopants within ion-implanted semiconductors. Sheet resistance and Hall measurements provide evidence of electrical activation. Susceptor-assisted MW annealing, of ion-implanted Si, enables more effective dopant activation and at lower temperatures than required for rapid thermal annealing (RTA). Raman spectroscopy and ion channeling analyses are used to monitor the extent of ion implantation damage and recrystallization. The presence and behavior of extended defects are monitored by cross-section transmission electron microscopy. Phosphorus implanted Si samples experience effective electrical activation upon MW annealing. On the other hand, when boron implanted Si is MW annealed, the growth of extended defects results in reduced crystalline quality that hinders the electrical activation process. Further comparison of dopant diffusion resulting from MW annealing and rapid thermal annealing is performed using secondary ion mass spectroscopy. MW annealed ion implanted samples show less end-of-range diffusion when compared to RTA samples. In particular, MW annealed P{sup +} implanted samples achieve no visible diffusion and equivalent electrical activation at a lower temperature and with a shorter time-duration of annealing compared to RTA. In this study, the peak temperature attained during annealing does not depend on the dopant species or dose, for susceptor-assisted MW annealing of ion-implanted Si.

  2. [Preparation, characterization and upconversion fluorescence of NaYF4 : Yb, Er /graphene oxide nanocomposites].

    Science.gov (United States)

    Ji, Tian-Hao; Qie, Nan; Wang, Ji-Mei; Hua, Yong-Yong; Ji, Zhi-Jiang

    2013-03-01

    NaYF4 : Yb, Er/rGO and SiO2-coated NaYF4 : Yb, Er/rGO nanocomposites can be prepared through "one-pot" and directly mixing preparation routes. Various measurement results show that the NaYF4 : Yb, Er in the nanocomposites exhibits a cubic a-type structure and nanoparticle-like morphology with a diameter range of 30-70 nm; the rGO layers are well-dispersed in the nanocomposites, and whereas the rGO obtained from "one-pot" preparation renders relatively better dispersion. Raman spectra demonstrate that there exists a surface coupling action between the two kinds of nanomaterials, and with the increase in the relative rGO content, such action becomes stronger. UC fluorescence measurement results reveal that the rGO has significantly quenching effect and optical-limiting performance on the UC fluorescence, particularly on the red-emission of the NaYFa : Yb, Er or SiO2-coated NaYF4 : Yb, Er nanoparticles. The red-emission intensity gradually decreases with an increase in the rGO content, but the green-emission shows less change. It should be stressed that, in comparison with NaYF4 : Yb, Er/rGO, with a similar rGO content, the red-emission intensity of SiO2-coated NaYF4 : Yb, Er/rGO decreases much obviously due to a stronger light-absorption caused by part rGO aggregation.

  3. Kronik: Diskussion om timetal er oldnordisk

    DEFF Research Database (Denmark)

    Koefoed Hansen, Lone

    2012-01-01

    Det er ikke antallet af timer med mig, underviseren, der afgør, hvor meget en studerende lærer. Det afgørende er derimod, hvad jeg formår at anspore de studerende til at lære, mens de ikke er i samme lokale som mig, skriver kronikøren....

  4. Hvorfor er sygeplejersker usynlige i offentlige medier?

    DEFF Research Database (Denmark)

    Joensen, Annemi Lund; Hall, Elisabeth

    2015-01-01

    Når der er sygeplejerelevante emner til debat i de offentlige medier på Færøerne, bærer debatten præg af sygeplejerskers manglende deltagelse. Sygeplejerskerne er usynlige. Et eksempel på dette er en debat om besparelser inden for ældreomsorgen. Til trods for at besparelsen fik omfattende konsekv...

  5. Peroxisomes: offshoots of the ER.

    Science.gov (United States)

    van der Zand, Adabella; Tabak, Henk F

    2013-08-01

    Peroxisomes are part of the ubiquitous set of eukaryotic organelles. They are small, single membrane bounded vesicles, specialized in the degradation of very-long-chain fatty acids and in synthesis of myelin lipids. Once considered inconspicuous, recent new insights in the formation and function of peroxisomes have revealed a much more subtle interplay between organelles that warrant a re-evaluation of the historical assignment of peroxisomes as being either autonomous or ER-derived. Peroxisomes acquire their lipids and membrane proteins from the ER, whereas they import their matrix proteins directly from the cytosol. Remarkably, many of its metabolic enzymes and factors controlling peroxisome abundance (fission and inheritance) too are shared with other organelles, stressing interdependence among cellular compartments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Highly Efficient Near-IR Photoluminescence of Er3+ Immobilized in Mesoporous SBA-15

    Directory of Open Access Journals (Sweden)

    Wu P

    2010-01-01

    Full Text Available Abstract SiO2 mesoporous molecular sieve SBA-15 with the incorporation of erbium ions is studied as a novel type of nanoscopic composite photoluminescent material in this paper. To enhance the photoluminescence efficiency, two schemes have been used for the incorporation of Er3+ where (1 Er3+ is ligated with bis-(perfluoromethylsulfonyl-aminate (PMS forming Er(PMSx-SBA-15 and (2 Yb3+ is codoped with Er3+ forming Yb-Er-SBA-15. As high as 11.17 × 10−21cm2 of fluorescent cross section at 1534 nm and 88 nm of “effective bandwidth” have been gained. It is a 29.3% boost in fluorescent cross section compared to what has been obtained in conventional silica. The upconversion coefficient in Yb-Er-SBA-15 is relatively small compared to that in other ordinary glass hosts. The increased fluorescent cross section and lowered upconversion coefficient could benefit for the high-gain optical amplifier. Finally, the Judd–Ofelt theory has also been used for the analyses of the optical spectra of Er(PMSx-SBA-15.

  7. Minimising Immunohistochemical False Negative ER Classification Using a Complementary 23 Gene Expression Signature of ER Status

    DEFF Research Database (Denmark)

    Li, Qiyuan; Eklund, Aron Charles; Birkbak, Nicolai Juul

    2010-01-01

    BACKGROUND: Expression of the oestrogen receptor (ER) in breast cancer predicts benefit from endocrine therapy. Minimising the frequency of false negative ER status classification is essential to identify all patients with ER positive breast cancers who should be offered endocrine therapies...... subtypes as compared to IHC-based determination has not been systematically evaluated. Here we attempt to reduce the frequency of false negative ER status classification using two gene expression approaches and compare these methods to IHC based ER status in terms of predictive and prognostic concordance....../SIGNIFICANCE: Expression-based ER status classification may complement IHC to minimise false negative ER status classification and optimise patient stratification for endocrine therapies....

  8. Selective emission and luminescence of Er2O3 under intense laser excitation

    Science.gov (United States)

    Marchenko, V. M.; Iskhakova, L. D.; Studenikin, M. I.

    2013-09-01

    The microstructure of Er2O3 polycrystals synthesised by laser heating is studied. The synthesis of erbium silicate (Er2SiO5) layers was observed upon interaction of Er2O3 and SiO2 melts. The dependences of the selective emission (SE) and luminescence spectra of Er2O3 polycrystals in the range 200 - 1700 nm on the intensity of laser-thermal (at the wavelength λ = 10.6 μm) and resonant laser (λ ≈ 975 nm) excitation are investigated. The emission of heated Er2O3 polycrystals arises as a result of multiphonon relaxation of absorbed energy and is a superposition of the SE at the electronic-vibrational transitions of Er3+ ions and the thermal radiation of the crystal lattice. The shape of the SE spectra of Er2O3 polycrystals in the range 400 - 1700 nm almost does not change upon laser-thermal heating from 300 to 1500 K and subsequent cooling and corresponds to the absorption spectra of Er3+ ions. With increasing temperature, the thermal radiation intensity increases faster than the SE intensity, and the shape of the Er2O3 spectrum becomes closer to the calculated spectrum of a blackbody. The anti-Stokes luminescence spectra of Er3+ ions formed under intense laser excitation of the 4I11/2 level are explained by additional SE caused by heating of the crystal matrix due to the Stokes losses. A difference between the SE and luminescence spectra is observed at low intensities of resonant laser excitation and low temperatures, when only the Stokes luminescence occurs. The temperature dependences of the SE and luminescence spectra of Er2O3 upon laser excitation testify to the fundamental role played by the interaction of the electronic f-shell of Er3+ ions with crystal lattice vibrations in the processes of multiphonon radiative and nonradiative relaxation. The laser-thermal synthesis is promising for inprocess variation of the chemical composition of rare-earth samples.

  9. Tank 241-ER-311, grab samples, ER311-98-1, ER311-98-2, ER311-98-3 analytical results for the final report

    Energy Technology Data Exchange (ETDEWEB)

    FULLER, R.K.

    1999-02-24

    This document is the final report for catch tank 241-ER-311 grab samples. Three grab samples ER311-98-1, ER311-98-2 and ER311-98-3 were taken from East riser of tank 241-ER-311 on August 4, 1998 and received by the 222-S Laboratory on August 4, 1998. Analyses were performed in accordance with the Compatibility Grab Sampling and Analysis Plan (TSAP) (Sasaki, 1998)and the Data Quality Objectives for Tank Farms Waste Compatibility Program (DQO) (Mulkey and Miller, 1997). The analytical results are presented in the data summary report (Table 1). No notification limits were exceeded.

  10. Association of FGFR1 with ERα Maintains Ligand-Independent ER Transcription and Mediates Resistance to Estrogen Deprivation in ER+ Breast Cancer.

    Science.gov (United States)

    Formisano, Luigi; Stauffer, Kimberly M; Young, Christian D; Bhola, Neil E; Guerrero-Zotano, Angel L; Jansen, Valerie M; Estrada, Mónica M; Hutchinson, Katherine E; Giltnane, Jennifer M; Schwarz, Luis J; Lu, Yao; Balko, Justin M; Deas, Olivier; Cairo, Stefano; Judde, Jean-Gabriel; Mayer, Ingrid A; Sanders, Melinda; Dugger, Teresa C; Bianco, Roberto; Stricker, Thomas; Arteaga, Carlos L

    2017-10-15

    Purpose:FGFR1 amplification occurs in approximately 15% of estrogen receptor-positive (ER+) human breast cancers. We investigated mechanisms by which FGFR1 amplification confers antiestrogen resistance to ER+ breast cancer.Experimental Design: ER+ tumors from patients treated with letrozole before surgery were subjected to Ki67 IHC, FGFR1 FISH, and RNA sequencing (RNA-seq). ER+/FGFR1-amplified breast cancer cells, and patient-derived xenografts (PDX) were treated with FGFR1 siRNA or the FGFR tyrosine kinase inhibitor lucitanib. Endpoints were cell/xenograft growth, FGFR1/ERα association by coimmunoprecipitation and proximity ligation, ER genomic activity by ChIP sequencing, and gene expression by RT-PCR.Results: ER+/FGFR1-amplified tumors in patients treated with letrozole maintained cell proliferation (Ki67). Estrogen deprivation increased total and nuclear FGFR1 and FGF ligands expression in ER+/FGFR1-amplified primary tumors and breast cancer cells. In estrogen-free conditions, FGFR1 associated with ERα in tumor cell nuclei and regulated the transcription of ER-dependent genes. This association was inhibited by a kinase-dead FGFR1 mutant and by treatment with lucitanib. ChIP-seq analysis of estrogen-deprived ER+/FGFR1-amplified cells showed binding of FGFR1 and ERα to DNA. Treatment with fulvestrant and/or lucitanib reduced FGFR1 and ERα binding to DNA. RNA-seq data from FGFR1-amplified patients' tumors treated with letrozole showed enrichment of estrogen response and E2F target genes. Finally, growth of ER+/FGFR1-amplified cells and PDXs was more potently inhibited by fulvestrant and lucitanib combined than each drug alone.Conclusions: These data suggest the ERα pathway remains active in estrogen-deprived ER+/FGFR1-amplified breast cancers. Therefore, these tumors are endocrine resistant and should be candidates for treatment with combinations of ER and FGFR antagonists. Clin Cancer Res; 23(20); 6138-50. ©2017 AACR. ©2017 American Association for Cancer

  11. Current concepts in the use of lasers in periodontal and implant dentistry

    Science.gov (United States)

    Romanos, Georgios

    2015-01-01

    Lasers have various periodontal applications including calculus removal (Er: YAG, Er, Cr: YSGG lasers); soft tissue excision, incision and ablation; decontamination of root and implant surfaces; biostimulation; bacteria reduction; and osseous surgery. This paper reviews some of the major opportunities for using lasers in periodontal and implant specialty practices. The literature relating to the use of lasers for removal of the pocket epithelium, root conditioning, bacterial reduction and decontamination of infected implant surfaces is discussed, and a summary of the advantages and disadvantages of using lasers for periodontal treatment is provided. PMID:26644712

  12. Current concepts in the use of lasers in periodontal and implant dentistry.

    Science.gov (United States)

    Romanos, Georgios

    2015-01-01

    Lasers have various periodontal applications including calculus removal (Er: YAG, Er, Cr: YSGG lasers); soft tissue excision, incision and ablation; decontamination of root and implant surfaces; biostimulation; bacteria reduction; and osseous surgery. This paper reviews some of the major opportunities for using lasers in periodontal and implant specialty practices. The literature relating to the use of lasers for removal of the pocket epithelium, root conditioning, bacterial reduction and decontamination of infected implant surfaces is discussed, and a summary of the advantages and disadvantages of using lasers for periodontal treatment is provided.

  13. Mitochondria-Associated Membranes and ER Stress.

    Science.gov (United States)

    van Vliet, Alexander R; Agostinis, Patrizia

    2017-03-28

    The endoplasmic reticulum (ER) is a crucial organelle for coordinating cellular Ca(2+) signaling and protein synthesis and folding. Moreover, the dynamic and complex membranous structures constituting the ER allow the formation of contact sites with other organelles and structures, including among others the mitochondria and the plasma membrane (PM). The contact sites that the ER form with mitochondria is a hot topic in research, and the nature of the so-called mitochondria-associated membranes (MAMs) is continuously evolving. The MAMs consist of a proteinaceous tether that physically connects the ER with mitochondria. The MAMs harness the main functions of both organelles to form a specialized subcompartment at the interface of the ER and mitochondria. Under homeostatic conditions, MAMs are crucial for the efficient transfer of Ca(2+) from the ER to mitochondria, and for proper mitochondria bioenergetics and lipid synthesis. MAMs are also believed to be the master regulators of mitochondrial shape and motility, and to form a crucial site for autophagosome assembly. Not surprisingly, MAMs have been shown to be a hot spot for the transfer of stress signals from the ER to mitochondria, most notably under the conditions of loss of ER proteostasis, by engaging the unfolded protein response (UPR). In this chapter after an introduction on ER biology and ER stress, we will review the emerging and key signaling roles of the MAMs, which have a root in cellular processes and signaling cascades coordinated by the ER.

  14. A two-short-implant-supported molar restoration in atrophic posterior maxilla: A finite element analysis

    Science.gov (United States)

    2016-01-01

    PURPOSE The aim of this study was to investigate the stress distribution of 2-short implants (2SIs) installed in a severely atrophic maxillary molar site. MATERIALS AND METHODS Three different diameters of internal connection implants were modeled: narrow platform (NP), regular platform (RP), and wide platform (WP). The maxillary first molars were restored with one implant or two short implants. Three 2SI models (NP-oblique, NP-vertical, and NP-horizontal) and four single implant models (RP and WP in a centered or cantilevered position) were used. Axial and oblique loadings were applied on the occlusal surface of the crown. The von Mises stress values were measured at the bone-implant, peri-implant bone, and implant/abutment complex. RESULTS The highest stress distribution at the bone-implant interface and the peri-implant bone was noticed in the RP group, and the lowest stress distribution was observed in the 2SI groups. Cantilevered position showed unfavorable stress distribution with axial loading. 2SI types did not affect the stress distribution in oblique loading. The number and installation positions of the implant, rather than the bone level, influenced the stress distribution of 2SIs. The implant/abutment complex of WP presented the highest stress concentration while that of 2SIs showed the lowest stress concentration. CONCLUSION 2SIs may be useful for achieving stable stress distribution on the surrounding bone and implant-abutment complex in the atrophic posterior maxilla. PMID:27555900

  15. ARTEMIN promotes de novo angiogenesis in ER negative mammary carcinoma through activation of TWIST1-VEGF-A signalling.

    Directory of Open Access Journals (Sweden)

    Arindam Banerjee

    Full Text Available The neurotrophic factor ARTEMIN (ARTN has been reported to possess a role in mammary carcinoma progression and metastasis. Herein, we report that ARTN modulates endothelial cell behaviour and promotes angiogenesis in ER-mammary carcinoma (ER-MC. Human microvascular endothelial cells (HMEC-1 do not express ARTN but respond to exogenously added, and paracrine ARTN secreted by ER-MC cells. ARTN promoted endothelial cell proliferation, migration, invasion and 3D matrigel tube formation. Angiogenic behaviour promoted by ARTN secreted by ER-MC cells was mediated by AKT with resultant increased TWIST1 and subsequently VEGF-A expression. In a patient cohort of ER-MC, ARTN positively correlated with VEGF-A expression as measured by Spearman's rank correlation analysis. In xenograft experiments, ER-MC cells with forced expression of ARTN produced tumors with increased VEGF-A expression and increased microvessel density (CD31 and CD34 compared to tumors formed by control cells. Functional inhibition of ARTN by siRNA decreased the angiogenic effects of ER-MC cells. Bevacizumab (a humanized monoclonal anti-VEGF-A antibody partially inhibited the ARTN mediated angiogenic effects of ER-MC cells and combined inhibition of ARTN and VEGF-A by the same resulted in further significant decrease in the angiogenic effects of ER-MC cells. Thus, ARTN stimulates de novo tumor angiogenesis mediated in part by VEGF-A. ARTN therefore co-ordinately regulates multiple aspects of tumor growth and metastasis.

  16. A novel method for effective sodium ion implantation into silicon

    Science.gov (United States)

    Lu, Qiu Yuan; Chu, Paul K.

    2012-07-01

    Although sodium ion implantation is useful to the surface modification of biomaterials and nano-electronic materials, it is a challenging to conduct effective sodium implantation by traditional implantation methods due to its high chemical reactivity. In this paper, we present a novel method by coupling a Na dispenser with plasma immersion ion implantation and radio frequency discharge. X-ray photoelectron spectroscopy (XPS) depth profiling reveals that sodium is effectively implanted into a silicon wafer using this apparatus. The Na 1s XPS spectra disclose Na2O-SiO2 bonds and the implantation effects are confirmed by tapping mode atomic force microscopy. Our setup provides a feasible way to conduct sodium ion implantation effectively.

  17. A novel method for effective sodium ion implantation into silicon

    Energy Technology Data Exchange (ETDEWEB)

    Lu Qiuyuan; Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

    2012-07-15

    Although sodium ion implantation is useful to the surface modification of biomaterials and nano-electronic materials, it is a challenging to conduct effective sodium implantation by traditional implantation methods due to its high chemical reactivity. In this paper, we present a novel method by coupling a Na dispenser with plasma immersion ion implantation and radio frequency discharge. X-ray photoelectron spectroscopy (XPS) depth profiling reveals that sodium is effectively implanted into a silicon wafer using this apparatus. The Na 1s XPS spectra disclose Na{sub 2}O-SiO{sub 2} bonds and the implantation effects are confirmed by tapping mode atomic force microscopy. Our setup provides a feasible way to conduct sodium ion implantation effectively.

  18. Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Mehrnaz Karimi

    1993-03-01

    Full Text Available People with profound hearing loss are not able to use some kinds of conventional amplifiers due to the nature of their loss. In these people, hearing sense is stimulated only when the auditory nerve is activated via electrical stimulation. This stimulation is possible through cochlear implant. In fact, for the deaf people who have good mental health and can not use surgical and medical treatment and also can not benefit from air and bone conduction hearing aids, this device is used if they have normal central auditory system. The basic parts of the device included: Microphone, speech processor, transmitter, stimulator and receiver, and electrode array.

  19. Cochlear Implant

    Directory of Open Access Journals (Sweden)

    Mehrnaz Karimi

    1992-04-01

    Full Text Available People with profound hearing loss are not able to use some kinds of conventional amplifiers due to the nature of their loss . In these people, hearing sense is stimulated only when the auditory nerve is activated via electrical stimulation. This stimulation is possible through cochlear implant. In fact, for the deaf people who have good mental health and can not use surgical and medical treatment and also can not benefit from air and bone conduction hearing aids, this device is used if they have normal central auditory system. The basic parts of the device included: Microphone, speech processor, transmitter, stimulator and receiver, and electrode array.

  20. Breast reconstruction - implants

    Science.gov (United States)

    Breast implants surgery; Mastectomy - breast reconstruction with implants; Breast cancer - breast reconstruction with implants ... to make reconstruction easier. If you will have breast reconstruction later, your surgeon will remove enough skin ...

  1. Degradation of implant materials

    CERN Document Server

    Eliaz, Noam

    2012-01-01

    This book surveys the degradation of implant materials, reviewing in detail such failure mechanisms as corrosion, fatigue and wear, along with monitoring techniques. Surveys common implant biomaterials, as well as procedures for implant retrieval and analysis.

  2. Hernia Surgical Mesh Implants

    Science.gov (United States)

    ... Procedures Implants and Prosthetics Hernia Surgical Mesh Implants Hernia Surgical Mesh Implants Share Tweet Linkedin Pin it ... between patients and their surgeons. What is a Hernia? A hernia occurs when an organ, intestine or ...

  3. Surface and bulk vibrations in ion-implanted amorphous silica

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, G. W.

    1980-01-01

    Infrared reflection spectroscopy (IRS) has been used to identify the Si-O vibrational mode and confirm previous assignments of Si-OH, and Si-OD vibrational modes in porous amorphous silica implanted with heavy ions and with H/sup +/ and D/sup +/ ions. The Si-O stretching mode (approx. 1015 cm/sup -1/) is produced by the damage cascade and is seen in all implanted bulk silicas as well as in porous silica. Implantation of porous silica with H/sup +/ and D/sup +/ ions produces bands at approx. 985 cm/sup -1/ and approx. 960 cm-/sup 1/, respectively. The position of all three bands is consistent with O, OH, and OD mass considerations. Implantation of D/sup +/ ions into porous silica containing molecular water and OH/sup -/ groups results in D-H exchange. The Si-OH and Si-OD vibrations are also seen in the bulk fused silica at low H/D fluences. These results suggest that intrinsic E'-type defects in bulk silica and dangling Si bonds at internal surface sites.

  4. Nanotechnology and Dental Implants

    OpenAIRE

    Sandrine Lavenus; Guy Louarn; Pierre Layrolle

    2010-01-01

    The long-term clinical success of dental implants is related to their early osseointegration. This paper reviews the different steps of the interactions between biological fluids, cells, tissues, and surfaces of implants. Immediately following implantation, implants are in contact with proteins and platelets from blood. The differentiation of mesenchymal stem cells will then condition the peri-implant tissue healing. Direct bone-to-implant contact is desired for a biomechanical anchoring of i...

  5. ER Stress and Lipid Metabolism in Adipocytes

    Directory of Open Access Journals (Sweden)

    Beth S. Zha

    2012-01-01

    Full Text Available The role of endoplasmic reticulum (ER stress is a rapidly emerging field of interest in the pathogenesis of metabolic diseases. Recent studies have shown that chronic activation of ER stress is closely linked to dysregulation of lipid metabolism in several metabolically important cells including hepatocytes, macrophages, β-cells, and adipocytes. Adipocytes are one of the major cell types involved in the pathogenesis of the metabolic syndrome. Recent advances in dissecting the cellular and molecular mechanisms involved in the regulation of adipogenesis and lipid metabolism indicate that activation of ER stress plays a central role in regulating adipocyte function. In this paper, we discuss the current understanding of the potential role of ER stress in lipid metabolism in adipocytes. In addition, we touch upon the interaction of ER stress and autophagy as well as inflammation. Inhibition of ER stress has the potential of decreasing the pathology in adipose tissue that is seen with energy overbalance.

  6. Endoplasmic reticulum: ER stress regulates mitochondrial bioenergetics

    Science.gov (United States)

    Bravo, Roberto; Gutierrez, Tomás; Paredes, Felipe; Gatica, Damián; Rodriguez, Andrea E.; Pedrozo, Zully; Chiong, Mario; Parra, Valentina; Quest, Andrew F.G.; Rothermel, Beverly A.; Lavandero, Sergio

    2014-01-01

    Endoplasmic reticulum (ER) stress activates an adaptive unfolded protein response (UPR) that facilitates cellular repair, however, under prolonged ER stress, the UPR can ultimately trigger apoptosis thereby terminating damaged cells. The molecular mechanisms responsible for execution of the cell death program are relatively well characterized, but the metabolic events taking place during the adaptive phase of ER stress remain largely undefined. Here we discuss emerging evidence regarding the metabolic changes that occur during the onset of ER stress and how ER influences mitochondrial function through mechanisms involving calcium transfer, thereby facilitating cellular adaptation. Finally, we highlight how dysregulation of ER–mitochondrial calcium homeostasis during prolonged ER stress is emerging as a novel mechanism implicated in the onset of metabolic disorders. PMID:22064245

  7. Dyskalkuli - er det et overset problem?

    DEFF Research Database (Denmark)

    Johansen, Lene Østergaard

    2006-01-01

    norm) til at klare sig i nutidens og fremtidens samfund. I de senere år er vi i Danmark begyndt at søge viden om elevers vanskeligheder med at lære matematik; et arbejde, der er stærkt støttet af en række nordiske kollegaer. Vanskeligheder med at lære matematik er et meget komplekst og mangesidigt...

  8. Fanggitter beskytter svage køer

    DEFF Research Database (Denmark)

    Thomsen, Peter

    2006-01-01

    KvægInfo nr.: 1574  Dato: 13-02-2006  Forfatter: Peter Thomsen   Fanggitter beskytter svage køer Ny forskning dokumenterer, at foderbord med fanggitter giver færre aggressioner og beskytter de svage køer. Selvom køernes samlede ædetid er den samme i staldsystemer med henholdsvis fanggitter og...

  9. Complications after cardiac implantable electronic device implantations

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard

    2013-01-01

    Complications after cardiac implantable electronic device (CIED) treatment, including permanent pacemakers (PMs), cardiac resynchronization therapy devices with defibrillators (CRT-Ds) or without (CRT-Ps), and implantable cardioverter defibrillators (ICDs), are associated with increased patient...

  10. Emission properties of Er-doped GaN as a function of Ga Flux

    Science.gov (United States)

    Nyein, Ei Ei; Hommerich, Uwe; Lee, D. S.; Steckl, Andrew; Zavada, John

    2002-03-01

    We are currently investigating the photoluminescence (PL) properties of Er-doped GaN for possible applications in thin-film electroluminescence (TFEL) devices. In this paper we report results on the green (537,558nm) and infrared (1.54μm) PL of Er-doped GaN as a function of Ga Flux. The investigated samples were prepared by solid-source molecular beam epitaxy on Si (111) substrates. The Ga Flux varied from 1x10-7torr (N-rich growth) to 9x10-7torr (Ga-rich growth). It was noted that the Ga Flux is a critical growth parameter strongly influencing the Er^3+ PL Intensity. The strongest Er^3+ PL was observed under slightly N-rich conditions (Ga Flux: 4.5x10-7torr) close to stoichiometric growth for both carrier-mediated excitation and direct intra-4f excitation. Under Ga-rich growth conditions, a rapid decrease of the Er^3+ PL was observed. On the contrary, the GaN band-edge PL reached its maximum intensity in the Ga-rich growth regime. More detailed investigations of the Ga flux optimization of Er-doped GaN including temperature dependent PL spectra and lifetime studies will be presented at the conference.

  11. DEM generation using ERS-ENVISAT interferometry

    Science.gov (United States)

    Wegmüller, Urs; Santoro, Maurizio; Werner, Charles; Strozzi, Tazio; Wiesmann, Andreas; Lengert, Wolfgang

    2009-09-01

    Space-borne SAR interferometry is one possible method for the generation of digital elevation models (DEMs). The sensitivity of this technique depends strongly on system parameters as the time interval between the observations used and the spatial baseline. Longer time intervals are less suited because of temporal decorrelation of the signal. Longer spatial baselines result in an increased height sensitivity. ERS-2 and ENVISAT ASAR operate in identical orbits at slightly different sensor frequencies with ASAR preceding ERS-2 by 28 min. This configuration offers a unique opportunity to study and apply ERS-ENVISAT interferometry. ERS-2-ENVISAT ASAR IS2 VV-polarization interferograms are characterized by a short 28 min repeat-pass interval and a long 1.5-2.5 km baseline. Given the long baseline and short time interval ERS-ENVISAT interferometry has a good potential for the generation of precise DEMs in relatively flat areas. The idea to use ERS-ENVISAT interferometry for DEM generation is not new, nevertheless, very few adequate data sets were identified and analyzed in the past. Now, thanks to a recent dedicated ERS-2-ENVISAT Tandem mission of ESA many well suited data sets became available. In this paper the ERS-ENVISAT interferometry methodology is described, its feasibility is demonstrated by presenting ERS-ENVISAT interferometry DEMs over several sites, and its potential is assessed.

  12. Er virksomheder deres sociale ansvar voksent?

    DEFF Research Database (Denmark)

    Øhrgaard, Per

    2018-01-01

    Eftertanken. Virksomheder er i dag ramt af en CSR-bølge. Men hvis definitionen af, hvad et samfundsmæssigt ansvar er, glider over på virksomhedernes hænder, glider det væk fra alle os andre.......Eftertanken. Virksomheder er i dag ramt af en CSR-bølge. Men hvis definitionen af, hvad et samfundsmæssigt ansvar er, glider over på virksomhedernes hænder, glider det væk fra alle os andre....

  13. Physical studies of strained Si/SiGe heterostructures. From virtual substrates to nanodevices

    Energy Technology Data Exchange (ETDEWEB)

    Minamisawa, Renato Amaral

    2011-10-21

    During the past two decades, the decrease in intrinsic delay of MOSFETs has been driven by the scaling of the device dimensions. The performance improvement has relied mostly in the increase of source velocity with gate scaling, while the transport properties of the channel have remained constant, i.e., those of conventional Si. Starting at the 90 nm node, uniaxial strain has been introduced in the transistor channel in order to further increase the source velocity. Beyond the 32 nm node, novel channel materials, with superior carrier velocities, and novel device architectures are required in order to continue the performance enhancement of MOSFETs while preserving the electrostatic control. In this Thesis, different physical aspects of strained Si and SiGe materials are investigated as a mean to increase carrier velocity in MOSFET channels. Novel approaches for the fabrication of strained Si based on ion implantation and anneal induced relaxation of virtual substrates are developed. The strain relaxation of SiGe layers is improved using a buried thin Si:C layer in the Si(100) substrate. Further, a Si{sup +} ion implantation and annealing method is investigated for relaxing virtual substrates using lower implantation dose. Finally, the uniaxial relaxation of {l_brace}110{r_brace} surface oriented substrates is demonstrated using a He ion implantation and anneal technique. Apart of channel material studies, the fundamental and technological challenges involved in the integration of strained Si and SiGe into MOSFETs are assessed. The impact of source and drain formation on the elastic strain and electrical properties of strained Si layers and nanowires is examined. Also, the formation of ultra-shallow junction in strained Si/strained Si{sub 0.5}Ge{sub 0.5}/SSOI heterostructures is investigated using different types of ion implanted specie and annealing. The results show that BF{sup +}{sub 2} implantation and low temperature annealing are suitable approaches for

  14. Electron Spectroscopy Study of SiC,

    Science.gov (United States)

    1983-09-01

    Liquid nitrogen cooling is supplied to the central copper block of the sample holder by flexible spiral stainless steel capillary. This cooling facility...sapphire disks from thinner copper blocks at both sides. The outer copper blocks hold 1.5 mm diameter W rods to which are welded a pair of 0.375 mm...sputtering was sufficient to implant F+ and Ar+ ions deep enough in the SiC surface layer, so that the implanted F and Ar could not be removed-by thermal

  15. Relationship between 4H-SiC/SiO2 transition layer thickness and mobility

    Science.gov (United States)

    Biggerstaff, T. L.; Reynolds, C. L.; Zheleva, T.; Lelis, A.; Habersat, D.; Haney, S.; Ryu, S.-H.; Agarwal, A.; Duscher, G.

    2009-07-01

    The interfacial region between silicon carbide (SiC) and its native oxide contains a high density of interfacial traps, which is considered a major problem leading to a lower mobility that has hindered SiC metal oxide semiconductor field effect transistors from reaching their theoretical expectations. We investigate the microstructure and chemistry of the 4H-SiC/SiO2 interface due to variations in nitric oxide annealing and aluminum implantation using Z-contrast imaging and electron energy loss spectroscopy. A transition layer with a carbon to silicon ratio greater than 1 is consistently observed on the SiC side of the interface in each of these samples, and the width of this transition layer is found to be inversely related to the effective channel mobility measured on fabricated devices.

  16. Ungdomslitteratur former(er) sig

    DEFF Research Database (Denmark)

    Henkel, Ayoe Qvist

    2016-01-01

    Igennem en 'mediesensitiv' analyse af romanen "Akavet" af Ronnie Andersen (2014) og perspektivering til andre aktuelle romaner for og med unge undersøger artiklen, hvordan ungdomslitteratur udvikler sig i dialog med digitale og mediebaserede impulser, og hvilke konsekvenser for udsigelserne om...... ungdomsliv og ungdomslitteraturens æstetik og mulige egenart, denne udvikling har. Artiklen baserer sig på en materialitetstilgang særligt inspireret af N. Katherine Hayles, som ikke tidligere har fået opmærksomhed i læsninger af ungdomslitteratur eller i diskussioner af ungdomslitteraturens mulige egenart......, at ungdomslitteratur drejer sig om unges udviklingsproces fra barndom og til voksenhed og dermed skildrer en overgang præget af linearitet, modning og vækst. Artiklen konkluderer, at der er ungdomslitteratur, der realiseres på andre præmisser, og Akavet kan ses som eksponent for en bevægelse fra ungdomslitteratur som...

  17. Study of radiation damage restoration and antimony ions redistribution in Si(1 0 0) and Si(1 1 1) crystals

    Science.gov (United States)

    Labbani, R.; Halimi, R.; Chafi, Z.

    2002-03-01

    In this work, we study the radiation damage restoration and antimony ions redistribution into and oriented silicon substrates. The samples are implanted with antimony to a dose of 5×10 14 Sb + cm -2 at 60 keV energy, then annealed under oxygen atmosphere at 900°C, 30 min. The thin layer of SiO 2 (which is formed on Si surface by dry oxidation and expected to prevent any loss of Sb + dopant during Si recovery) is removed by a 10% HF solution. The specimens are analyzed by H + Rutherford Backscattering Spectrometry (RBS) operating at 0.3 MeV energy in both random and channelling modes. The values of the projected range, Rp, the standard deviation, Δ Rp, and the dose of antimony ions, which are estimated with a simple program, are in agreement with tabulated ones. It is also shown that the surface damage restoration is better for Si(1 0 0) samples than for Si(1 1 1) ones, in other words, the radiation damage is more significant in Si(1 1 1) substrates. Moreover, for both Si(1 0 0) and Si(1 1 1), it has been noticed that an important quantity of implanted antimony is localized in substitutional silicon sites. This fact is more pronounced in Si(1 0 0). On the other hand, it has been found, for Si(1 0 0) substrates only, that antimony ions are redistributed into the silicon lattice following a Gaussian law.

  18. In Vitro Laser Treatment Platform Construction with Dental Implant Thread Surface on Bacterial Adhesion for Peri-Implantitis

    Science.gov (United States)

    Mei, Hsiang-I; Liu, Tse-Ying; Lo, Lun-Jou

    2017-01-01

    This study constructs a standard in vitro laser treatment platform with dental implant thread surface on bacterial adhesion for peri-implantitis at different tooth positions. The standard clinical adult tooth jaw model was scanned to construct the digital model with 6 mm bone loss depth on behalf of serious peri-implantitis at the incisor, first premolar, and first molar. A cylindrical suite connected to the implant and each tooth root in the jaw model was designed as one experimental unit set to allow the suite to be replaced for individual bacterial adhesion. The digital peri-implantitis and suite models were exported to fulfill the physical model using ABS material in a 3D printer. A 3 mm diameter specimen implant on bacterial adhesion against Escherichia coli was performed for gram-negative bacteria. An Er:YAG laser, working with a chisel type glass tip, was moved from the buccal across the implant thread to the lingual for about 30 seconds per sample to verify the in vitro laser treatment platform. The result showed that the sterilization rate can reach 99.3% and the jaw model was not damaged after laser irradiation testing. This study concluded that using integrated image processing, reverse engineering, CAD system, and a 3D printer to construct a peri-implantitis model replacing the implant on bacterial adhesion and acceptable sterilization rate proved the feasibility of the proposed laser treatment platform. PMID:28791302

  19. In Vitro Laser Treatment Platform Construction with Dental Implant Thread Surface on Bacterial Adhesion for Peri-Implantitis

    Directory of Open Access Journals (Sweden)

    Hsien-Nan Kuo

    2017-01-01

    Full Text Available This study constructs a standard in vitro laser treatment platform with dental implant thread surface on bacterial adhesion for peri-implantitis at different tooth positions. The standard clinical adult tooth jaw model was scanned to construct the digital model with 6 mm bone loss depth on behalf of serious peri-implantitis at the incisor, first premolar, and first molar. A cylindrical suite connected to the implant and each tooth root in the jaw model was designed as one experimental unit set to allow the suite to be replaced for individual bacterial adhesion. The digital peri-implantitis and suite models were exported to fulfill the physical model using ABS material in a 3D printer. A 3 mm diameter specimen implant on bacterial adhesion against Escherichia coli was performed for gram-negative bacteria. An Er:YAG laser, working with a chisel type glass tip, was moved from the buccal across the implant thread to the lingual for about 30 seconds per sample to verify the in vitro laser treatment platform. The result showed that the sterilization rate can reach 99.3% and the jaw model was not damaged after laser irradiation testing. This study concluded that using integrated image processing, reverse engineering, CAD system, and a 3D printer to construct a peri-implantitis model replacing the implant on bacterial adhesion and acceptable sterilization rate proved the feasibility of the proposed laser treatment platform.

  20. Enhancement of Ag nanoparticles concentration by prior ion implantation

    Science.gov (United States)

    Mu, Xiaoyu; Wang, Jun; Liu, Changlong

    2017-09-01

    Thermally grown SiO2 layer on Si substrates were singly or sequentially implanted with Zn or Cu and Ag ions at the same fluence of 2 × 1016/cm2. The profiles of implanted species, structure, and spatial distribution of the formed nanoparticles (NPs) have been characterized by the cross-sectional transmission electron microscope (XTEM) and Rutherford backscattering spectrometry (RBS). It is found that pre-implantation of Zn or Cu ions could suppress the self sputtering of Ag atoms during post Ag ion implantation, which gives rise to fabrication of Ag NPs with a high density. Moreover, it has also been demonstrated that the suppressing effect strongly depends on the applied energy and mobility of pre-implanted ions. The possible mechanism for the enhanced Ag NPs concentration has been discussed in combination with SRIM simulations. Both vacancy-like defects acting as the increased nucleation sites for Ag NPs and a high diffusivity of prior implanted ions in SiO2 play key roles in enhancing the deposition of Ag implants.

  1. Er der en underviser til stede?

    DEFF Research Database (Denmark)

    Christiansen, René Boyer; Nortvig, Anne-Mette; Rosenlund, Lea Tilde

    2015-01-01

    I de senere år er MOOC (Massive Open Online Courses) blevet en faktor på uddannelsesområdet. MOOC-forskning er et forholdsvist nyt felt, men har inden for de seneste 2-3 år udviklet sig med hastige skridt (Liyanagunawardena et al. 2013, Bayne & Ross 2014). En stor del af denne forskning har haft...

  2. Hvorfor er Ernæringsdiagnosen vigtig?

    DEFF Research Database (Denmark)

    Winther, Eva

    2013-01-01

    Nutrition Care Process er en cirkulær firetrinsmodel for individuel eller gruppevis diætbehandling eller kostvejledning. Efter indsamling af oplysninger om klientens spisevaner bliver oplysningerne grupperet og analyseret, og der formuleres en syntese/ernæringsdiagnose. Ernæringsdiagnosen er en...

  3. "Det man siger er man selv..."

    DEFF Research Database (Denmark)

    Næsby, Torben; Nørgaard, Britta; Uddholm, Mats

    forhold, der er hermeneutisk, strukturelt og relationelt bestemt. Praksisviden kan ikke være objektiv i gængs forstand, men det behøver ikke at diskvalificere denne viden. Forståelse er altid knyttet til den sag og bundet til den situation man står overfor og i som professionel og som menneske....

  4. Der er kun én verden

    DEFF Research Database (Denmark)

    Hansen, Nils Gunder

    2013-01-01

    Klummeskriveren er langt væk hjemmefra, og globaliseringen går endelig op for ham, da han ser Golden Gate Bridge i San Francisco......Klummeskriveren er langt væk hjemmefra, og globaliseringen går endelig op for ham, da han ser Golden Gate Bridge i San Francisco...

  5. Coronavirus infection, ER stress and Apoptosis

    Directory of Open Access Journals (Sweden)

    TO SING eFUNG

    2014-06-01

    Full Text Available The replication of coronavirus, a family of important animal and human pathogens, is closely associated with the cellular membrane compartments, especially the endoplasmic reticulum (ER. Coronavirus infection of cultured cells was previously shown to cause ER stress and induce the unfolded protein response (UPR, a process that aims to restore the ER homeostasis by global translation shutdown and increasing the ER folding capacity. However under prolonged ER stress, UPR can also induce apoptotic cell death. Accumulating evidence from recent studies has shown that induction of ER stress and UPR may constitute a major aspect of coronavirus-host interaction. Activation of the three branches of UPR modulates a wide variety of signaling pathways, such as mitogen-activated protein (MAP kinases activation, autophagy, apoptosis and innate immune response. ER stress and UPR activation may therefore contribute significantly to the viral replication and pathogenesis during coronavirus infection. In this review, we summarize current knowledge on coronavirus-induced ER stress and UPR activation, with emphasis on their cross-talking to apoptotic signaling.

  6. Multikulturalisme er en ny slags Apartheid

    DEFF Research Database (Denmark)

    Dyrberg, Torben Bech

    2016-01-01

    I en ny antologi retter forfatterne et kritisk lys mod forsvarerne af multikulturalisme. Og det er der god grund til, mener en af bogens redaktører. For den store gruppe, der hylder multikulturen, glemmer i al dens godhed, at de samtidig er med til at undergrave demokratiet og styrke uheldige mag...

  7. Helium implantation induced metal gettering in silicon at half of the projected ion range

    Science.gov (United States)

    Peeva, A.; Fichtner, P. F. P.; Behar, M.; Koegler, R.; Skorupa, W.

    2001-04-01

    Damage has been found in 40 keV He + ion-implanted Si away from the projected ion range Rp, mainly around Rp/2. Cu gettering has been used for detecting implantation induced defects which are formed during rapid thermal annealing (RTA) of 800°C/10 min. Transmission electron microscopy (TEM) micrographs show no visible defects at Rp/2. The Cu gettering peak at Rp/2 is well known for MeV-ion-implanted and annealed Si ( Rp/2 effect). In this study, the corresponding effect is observed for low-energy implantation of a light ion-like He.

  8. Er:YAG delamination of immersed biological membranes using sealed flexible hollow waveguides

    Science.gov (United States)

    Sagi-Dolev, A. M.; Dror, Jacob; Inberg, Alexandra; Ferencz, J. R.; Croitoru, Nathan I.

    1996-04-01

    The radiation of Er-YAG laser ((lambda) equals 2.94 micrometer) gives selective interaction with tissues. The extinction in soft tissues is only a few micrometers and in hard tissues is of the order of hundreds of micrometers. This makes this type of laser very suitable for treatments in dentistry, orthopedy, or ophthalmology. Because the usual silica fibers are not transmitting the radiation at lambda equals 2.94 micrometer of this laser, many applications cannot be presently performed. Fused silica hollow fibers for Er-YAG radiation were developed in our laboratory and several possible applications in dentistry, orthopedy and ophthalmology were indicated. Hole opening and implantation preparation of teeth were experimented, using Er-YAG laser and hollow plastic waveguide delivery systems. Hole drilling in cow bones was demonstrated for applications in orthopedy. A new procedure of delivering Er-YAG radiation on fibrotic membranes of inner eggshell as a model of the membranes in eyes was developed employing silica hollow waveguides of 0.5 and 0.7 mm ID or a plastic waveguide of 1.0 mm ID. For this purpose waveguides with sealed distal tip were employed to enable us to approach the delivery system through liquid media near to the membrane. This experiment demonstrates the possibility of surgical applications in vitectomy in ophthalmology using Er-YAG laser and silica hollow waveguides.

  9. Retrograde peri-implantitis

    Directory of Open Access Journals (Sweden)

    Mohamed Jumshad

    2010-01-01

    Full Text Available Retrograde peri-implantitis constitutes an important cause for implant failure. Retrograde peri-implantitis may sometimes prove difficult to identify and hence institution of early treatment may not be possible. This paper presents a report of four cases of (the implant placed developing to retrograde peri-implantitis. Three of these implants were successfully restored to their fully functional state while one was lost due to extensive damage. The paper highlights the importance of recognizing the etiopathogenic mechanisms, preoperative assessment, and a strong postoperative maintenance protocol to avoid retrograde peri-implant inflammation.

  10. ESR and spectral studies of Er{sup 3+} ions in soda-lime silicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Kaewwiset, W., E-mail: opticslaser@yahoo.com [Department of Physics, Faculty of Science, King Mongkut' s University of Technology, Thonburi, Bangkok 10140 (Thailand); Thamaphat, K. [Department of Physics, Faculty of Science, King Mongkut' s University of Technology, Thonburi, Bangkok 10140 (Thailand); Kaewkhao, J. [Center of Excellence in Glass Technology and Materials Science (CEGM), Faculty of Science and Technology, Nakhon Pathom Rajabhat University, Nakhon Pathom 73000 (Thailand); Thailand Center of Excellence in Physics, CHE, Ministry of Education, Bangkok 10400 (Thailand); Limsuwan, P. [Department of Physics, Faculty of Science, King Mongkut' s University of Technology, Thonburi, Bangkok 10140 (Thailand); Thailand Center of Excellence in Physics, CHE, Ministry of Education, Bangkok 10400 (Thailand)

    2013-01-15

    Electron spin resonance (ESR), optical absorption spectra and photoluminescence spectra of Er{sup 3+} ions in soda-lime silicate glasses doped with different concentrations of Er{sub 2}O{sub 3} have been studied. The glasses of the composition (in mol%) (65-x)SiO{sub 2}:25Na{sub 2}O:10CaO:xEr{sub 2}O{sub 3} (where x=0.02, 0.05, 0.1, 0.3, 0.5, 1, 2, 3, 4 and 5) were prepared by the melt quenching method. ESR measurements were carried out at room temperature down to 1.62 K. Absorption spectra were investigated in the UV-VIS-NIR region from 300 to 1800 nm. Photoluminescence spectra were observed in the spectral range 500-800 nm under 514.5 nm argon-ion laser line excitation.

  11. Geometric calibration of ERS satellite SAR images

    DEFF Research Database (Denmark)

    Mohr, Johan Jacob; Madsen, Søren Nørvang

    2001-01-01

    Geometric calibration of the European Remote Sensing (ERS) Satellite synthetic aperture radar (SAR) slant range images is important in relation to mapping areas without ground reference points and also in relation to automated processing. The relevant SAR system parameters are discussed and calib......Geometric calibration of the European Remote Sensing (ERS) Satellite synthetic aperture radar (SAR) slant range images is important in relation to mapping areas without ground reference points and also in relation to automated processing. The relevant SAR system parameters are discussed...... on a seven-year ERS-1 and a four-year ERS-2 time series, the long term stability is found to be sufficient to allow a single calibration covering the entire mission period. A descending and an ascending orbit tandem pair of the ESA calibration site on Flevoland, suitable for calibration of ERS SAR processors...

  12. Ligature-induced peri-implant infection in crestal and subcrestal implants: a clinical and radiographic study in dogs

    Directory of Open Access Journals (Sweden)

    Baoxin Huang

    2015-07-01

    Full Text Available Objective. The aim of this study was to assess the influence of implant–abutment interface (IAI placement depths on peri-implant tissues in the presence of ligature-induced peri-implant inflammation.Materials and Methods. Two implants with screwed-in IAIs (SI and two implants with tapped-in IAIs (TI were inserted in one side of the mandible in six dogs eight weeks after tooth extraction. Four experimental groups were constituted: SI placed crestally, SI placed 1.5 mm subcrestally, TI placed crestally and TI placed 1.5 mm subcrestally. After 12 weeks, the healing abutments were connected. Four weeks later, cotton floss ligatures were placed around the abutments to promote plaque accumulation. Clinical and radiographic examinations were performed at 0, 6 and 12 weeks after ligature placement. The effects of the IAI placement depths on clinical and radiographic parameters were assessed.Results. The alterations of peri-implant probing depths, clinical attachment levels, distances from the IAI to the first bone-implant contact (IAI-fBIC and depths of infrabony defect were significant larger in the subcrestal groups compared with the crestal groups during the plaque accumulation period. The alterations of clinical attachment levels, IAI-fBIC, depth of the infrabony defect and horizontal bone loss were not significantly different between the SI and TI groups after ligature placement.Conclusion. Tissue destruction in subcrestal implants may be more serious than that in crestal implants in the presence of inflamed peri-implant mucosa.

  13. The sarin-like organophosphorus agent bis(isopropyl methyl)phosphonate induces ER stress in human astrocytoma cells.

    Science.gov (United States)

    Arima, Yosuke; Shiraishi, Hiroaki; Saito, Atsushi; Yoshimoto, Kanji; Namera, Akira; Makita, Ryosuke; Murata, Kazuhiro; Imaizumi, Kazunori; Nagao, Masataka

    2016-01-01

    Organophosphorus (OP) compounds such as sarin are toxic agents that irreversibly inhibit the enzyme acetylcholinesterase. A recent study showed that OP compounds also have multiple toxicity mechanisms, and another suggested that endoplasmic reticulum (ER) dysfunction contributes to OP toxicity. However, the signaling pathway and mechanisms involved are poorly understood. We examined whether the sarin-like OP agent bis(isopropyl methyl)phosphonate (BIMP), which exhibits toxicity similar to that of sarin, induced ER stress in human astrocytoma CCF-STTG1 cells. Our results demonstrate that BIMP exposure reduced cell viability. Moreover, it induced changes in mitochondrial membrane potential and increased cleavage of caspase 3. Treatment with BIMP increased the mRNA levels of the ER stress marker genes binding immunoglobulin protein (BiP) and the transcription factor C/EBP homologous protein (CHOP). Furthermore, BIMP increased the protein expressions and phosphorylation of BiP, CHOP, and protein kinase RNA-like ER kinase and the phosphorylation of eukaryotic translation initiation factor 2. Compared to BIMP treatment alone, pretreatment with the CHOP siRNA, siCHOP, decreased BIMP-dependent CHOP expression and improved CCF-STTG1 cell viability. Our findings suggest that BIMP induced mitochondrial dysfunction and apoptotic cell death event mediated by ER stress in CCF-STTG1 cells and that treatment targeted at managing ER stress has the potential to attenuate the toxicity of OP nerve agents.

  14. Growth-temperature dependence of Er-doped GaN luminescent thin films

    Science.gov (United States)

    Lee, D. S.; Heikenfeld, J.; Steckl, A. J.

    2002-01-01

    Visible photoluminescence (PL) and electroluminescence (EL) emission has been observed from Er-doped GaN thin films grown on (111) Si at various temperatures from 100 to 750 °C in a radio-frequency plasma molecular beam epitaxy system. PL and EL intensities of green emission at 537 nm from GaN:Er films exhibited strong dependence on the growth temperature, with a maximum at 600 °C. Scanning electron and atomic force microscopy showed smooth surfaces at 600 °C and rough surfaces at 100 and 750 °C. X-ray diffraction indicated that the GaN:Er film structure was oriented with the c axis perpendicular to the substrate for all growth temperatures. The crystalline quality initially improves with an increase in growth temperature, and saturates at ˜500 °C. Considering both the luminescence and structural properties of the film, ˜600 °C seems to be the optimal temperature for growth of Er-doped GaN luminescent films on Si substrates.

  15. Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H. [pnnl; Alvine, Kyle J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Roosendaal, Timothy J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Shin, Yongsoon [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nguyen, Ba Nghiep; Borlaug, Brennan A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jiang, Weilin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arreguin, Shelly A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-01-15

    A new dual-phase nanocomposite of Ti₃SiC₂/SiC is being synthesized using preceramic polymers, ceramic powders, and carbon nanotubes (CNTs) designed to be suitable for advanced nuclear reactors and perhaps as fuel cladding. The material is being designed to have superior fracture toughness compared to SiC, adequate thermal conductivity, and higher density than SiC/SiC composites. This annual report summarizes the progress towards this goal and reports progress in understanding certain aspects of the material behavior but some shortcomings in achieving full density or in achieving adequate incorporation of CNTs. The measured thermal conductivity is adequate and falls into an expected range based on SiC and Ti₃SiC₂. Part of this study makes an initial assessment for Ti₃SiC₂ as a barrier to fission product transport. Ion implantation was used to introduce fission product surrogates (Ag and Cs) and a noble metal (Au) in Ti₃SiC₂, SiC, and a synthesized at PNNL. The experimental results indicate that the implanted Ag in SiC is immobile up to the highest temperature (1273 K) applied in this study; in contrast, significant out-diffusion of both Ag and Au in MAX phase Ti₃SiC₂ occurs during ion implantation at 873 K. Cs in Ti₃SiC₂ is found to diffuse during post-irradiation annealing at 973 K, and noticeable Cs release from the sample is observed. This study may suggest caution in using Ti₃SiC₂ as a fuel cladding material for advanced nuclear reactors operating at very high temperatures. Progress is reported in thermal conductivity modeling of SiC-based materials that is relevant to this research, as is progress in modeling the effects of CNTs on fracture strength of SiC-based materials.

  16. Single crystalline PtSi nanowires, PtSi/Si/PtSi nanowire heterostructures, and nanodevices.

    Science.gov (United States)

    Lin, Yung-Chen; Lu, Kuo-Chang; Wu, Wen-Wei; Bai, Jingwei; Chen, Lih J; Tu, K N; Huang, Yu

    2008-03-01

    We report the formation of PtSi nanowires, PtSi/Si/PtSi nanowire heterostructures, and nanodevices from such heterostructures. Scanning electron microscopy studies show that silicon nanowires can be converted into PtSi nanowires through controlled reactions between lithographically defined platinum pads and silicon nanowires. High-resolution transmission electron microscopy studies show that PtSi/Si/PtSi heterostructure has an atomically sharp interface with epitaxial relationships of Si[110]//PtSi[010] and Si(111)//PtSi(101). Electrical measurements show that the pure PtSi nanowires have low resistivities approximately 28.6 microOmega.cm and high breakdown current densities>1x10(8) A/cm2. Furthermore, using single crystal PtSi/Si/PtSi nanowire heterostructures with atomically sharp interfaces, we have fabricated high-performance nanoscale field-effect transistors from intrinsic silicon nanowires, in which the source and drain contacts are defined by the metallic PtSi nanowire regions, and the gate length is defined by the Si nanowire region. Electrical measurements show nearly perfect p-channel enhancement mode transistor behavior with a normalized transconductance of 0.3 mS/microm, field-effect hole mobility of 168 cm2/V.s, and on/off ratio>10(7), demonstrating the best performing device from intrinsic silicon nanowires.

  17. In vivo ultrasonic detection of polyurea crosslinked silica aerogel implants.

    Science.gov (United States)

    Sabri, Firouzeh; Sebelik, Merry E; Meacham, Ryan; Boughter, John D; Challis, Mitchell J; Leventis, Nicholas

    2013-01-01

    Polyurea crosslinked silica aerogels are highly porous, lightweight, and mechanically strong materials with great potential for in vivo applications. Recent in vivo and in vitro studies have demonstrated the biocompatibility of this type of aerogel. The highly porous nature of aerogels allows for exceptional thermal, electric, and acoustic insulating capabilities that can be taken advantage of for non-invasive external imaging techniques. Sound-based detection of implants is a low cost, non-invasive, portable, and rapid technique that is routinely used and readily available in major clinics and hospitals. In this study the first in vivo ultrasound response of polyurea crosslinked silica aerogel implants was investigated by means of a GE Medical Systems LogiQe diagnostic ultrasound machine with a linear array probe. Aerogel samples were inserted subcutaneously and sub-muscularly in a) fresh animal model and b) cadaveric human model for analysis. For comparison, samples of polydimethylsiloxane (PDMS) were also imaged under similar conditions as the aerogel samples. Polyurea crosslinked silica aerogel (X-Si aerogel) implants were easily identified when inserted in either of the regions in both fresh animal model and cadaveric model. The implant dimensions inferred from the images matched the actual size of the implants and no apparent damage was sustained by the X-Si aerogel implants as a result of the ultrasonic imaging process. The aerogel implants demonstrated hyperechoic behavior and significant posterior shadowing. Results obtained were compared with images acquired from the PDMS implants inserted at the same location.

  18. Doping porous silicon with erbium: pores filling as a method to limit the Er-clustering effects and increasing its light emission

    KAUST Repository

    Mula, Guido

    2017-07-14

    Er clustering plays a major role in hindering sufficient optical gain in Er-doped Si materials. For porous Si, the long-standing failure to govern the clustering has been attributed to insufficient knowledge of the several, concomitant and complex processes occurring during the electrochemical Er-doping. We propose here an alternative road to solve the issue: instead of looking for an equilibrium between Er content and light emission using 1-2% Er, we propose to significantly increase the electrochemical doping level to reach the filling the porous silicon pores with luminescent Er-rich material. To better understand the intricate and superposing phenomena of this process, we exploit an original approach based on needle electron tomography, EXAFS and photoluminescence. Needle electron tomography surprisingly shows a heterogeneous distribution of Er content in the silicon thin pores that until now couldn\\'t be revealed by the sole use of scanning electron microscopy compositional mapping. Besides, while showing that pore filling leads to enhanced photoluminescence emission, we demonstrate that the latter is originated from both erbium oxide and silicate. These results give a much deeper understanding of the photoluminescence origin down to nanoscale and could lead to novel approaches focused on noteworthy enhancement of Er-related photoluminescence in porous silicon.

  19. Der er ingen stemmer i kulturpolitik

    DEFF Research Database (Denmark)

    Rasmussen, Casper Hvenegaard

    og forbedret adgang til dannelseskulturen. For det andet har begreber som habitus, kulturel kapital og distinktion været kvalitative forklaringer på de problemer, som demokratiseringen af dannelseskulturen er stødt på. For det tredje sætter Bourdieus sene og mere normative forfatterskab fokus på......Der er flere grunde til at Pierre Bourdieu er bruges flittigt i den kulturpolitiske forskning. For det første er Bourdieus studier af feltbegrebet, og særligt udviklingen af den kunstneriske felt, en hjørnesten i forståelsen af en moderne vestlig kulturpolitik, der bygger på offentlig kunststøtte......, hvordan markedstanken udfordrer kulturfeltets autonomi. Det er særligt kulturfeltets vigende autonomi i en dansk kulturpolitisk kontekst og forandringer i den kulturelle kapital, der er omdrejningspunktet for dette paper. Det er en Bourdieu-inspireret analyse af det offentligt støttede dansk kulturliv...

  20. In-situ ER-doped GaN optical storage devices using high-resolution focused ion beam milling

    Science.gov (United States)

    Lee, Boon K.; Chi, Chih-Jen; Chyr, Irving; Lee, Dong-Seon; Beyette, Fred R.; Steckl, Andrew J.

    2002-04-01

    High-density GaN:Er optical storage devices were fabricated with focused ion beam (FIB) milling techniques. In-situ Er-doped GaN films (1 - 1.5 micrometers thick) were grown on Si substrates. To `write' a bit, the GaN:Er film was selectively milled with a 30-keV Ga+ FIB. Data retrieval is accomplished by upconversion emission at 535/556 nm upon 1-micrometers IR laser stimulation. Regions where the Er-doped GaN layer is completely removed (and do not emit) are defined as logic `0,' while regions that are not milled (and do emit) are defined as logic `1.' Data patterns with submicron bit size (or 100 Mb/cm2 density) have been fabricated by FIB milling. Data written by this approach has a theoretical storage capacity approaching 10 Gbits/cm2.

  1. Bioactive glass coatings for orthopedic metallic implants

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Esteban, Sonia; Saiz, Eduardo; Fujino, Sigheru; Oku, Takeo; Suganuma, Katsuaki; Tomsia, Antoni P.

    2003-06-30

    The objective of this work is to develop bioactive glass coatings for metallic orthopedic implants. A new family of glasses in the SiO2-Na2O-K2O-CaO-MgO-P2O5 system has been synthesized and characterized. The glass properties (thermal expansion, softening and transformation temperatures, density and hardness) are in line with the predictions of established empirical models. The optimized firing conditions to fabricate coatings on Ti-based and Co-Cr alloys have been determined and related to the glass properties and the interfacial reactions. Excellent adhesion to alloys has been achieved through the formation of 100-200 nm thick interfacial layers (Ti5Si3 on Ti-based alloys and CrOx on Co-Cr). Finally, glass coatings, approximately 100 mu m thick, have been fabricated onto commercial Ti alloy-based dental implants.

  2. FEA model analysis of the effects of the stress distribution of saddle-type implants on the alveolar bone and the structural/physical stability of implants.

    Science.gov (United States)

    Kong, Yoon Soo; Park, Jun Woo; Choi, Dong Ju

    2016-12-01

    As dental implants receive masticatory stress, the distribution of stress is very important to peri-implant bone homeostasis and implant survival. In this report, we created a saddle-type implant and analyzed its stability and ability to distribute stress to the surrounding bone. The implants were designed as a saddle-type implant (SI) that wrapped around the alveolar bone, and the sizes of the saddles were 2.5, 3.5, 4.5, and 5.5 mm. The X and Y displacement were compared to clarify the effects of the saddle structures. The control group consisted of dental implants without the saddle design (CI). Using finite element modeling (FEM), the stress distribution around the dental implants was analyzed. With saddle-type implants, saddles longer than 4.5 mm were more effective for stress distribution than CI. Regarding lateral displacement, a SI of 2.5 mm was effective for stress distribution compared to lateral displacement. ASI that was 5.6 mm in length was more effective for stress distribution than a CI that was 10 mm in length. The saddle-type implant could have a bone-gaining effect. Because it has stress-distributing effects, it might protect the newly formed bone under the implant.

  3. The effect of noise on the perception of prosody in cochlear implant listening

    DEFF Research Database (Denmark)

    Morris, David Jackson

    2011-01-01

    ’Du må ikke. Hold op.’ og ’Du må ikke holde op’ består af det samme ord, men semantisk set er de direkte modsætninger. I mundtlig kommunikation er det prosodi som tegner forskellen mellem de to. Cochlear Implant lyttere har det svært ved at opfatte prosodi især i støjende omgivelserne. Mit...

  4. Supervision og de tre k´er

    DEFF Research Database (Denmark)

    Schilling, Benedicte; Jacobsen, Claus Haugaard; Nielsen, Jan

    2010-01-01

    Kontrol, kontrakt og kontekst er supervisionens tre k'er. Men hvad er supervision i det hele taget for en størrelse, der spillerså central en rolle for den psykologfaglige profession?......Kontrol, kontrakt og kontekst er supervisionens tre k'er. Men hvad er supervision i det hele taget for en størrelse, der spillerså central en rolle for den psykologfaglige profession?...

  5. Hvordan er det å leve med CRPS?

    OpenAIRE

    Hovind, Thomas

    2014-01-01

    Hensikten med denne studien er å se på hvordan pasienter med komplekst regionalt smertesyndrom (CRPS) opplever å leve med tilstanden og hvordan disse pasientene har opplevd å bli møtt i helsevesenet. CRPS er en langvarig tilstand med sterke smerter som kan medføre økt smerterespons, redusert funksjon og nedsatt livskvalitet hos pasientene. Studien er en kvalitativ undersøkelse basert på dybdeintervju av fire pasienter med CRPS. Pasientene ble rekruttert fra en smerteavdeling i Nord-Norge og u...

  6. Ytringsfriheden er ikke nødvendig

    DEFF Research Database (Denmark)

    Lauritzen, Pia

    2008-01-01

    nemlig godt konstatere, at ytringsfriheden ikke er nødvendig uden dermed at give afkald på frihed og demokrati.Vi kan oven i købet mene, at ytringsfriheden ophører med at være frihed, når vi betragter den som nødvendig. Og det er lige nøjagtig det, jeg efterlyser: at vi bruger filosoffer som Immanuel...... Kant og Luigi Pareyson til at forstå, at friheden er betydelig mere kompleks, end vi gør den til i øjeblikket....

  7. En hat er vel en hat ... eller?

    DEFF Research Database (Denmark)

    Bøilerehauge, Dorrit

    2007-01-01

    Mens vi kører i høj fart på "the information highway" - i den helt store bus midt på vejen - glemmer vi ofte noget meget vigtigt i vores glæde over, at verden tilsyneladende åbner sig for os, og vi kan kommunikere med hele verden med ét klik. Vi glemmer, at selvom trafikskilte som oftest er ens -...... - så er selve trafikken og forventningerne blandt medtrafikanterne helt forskellige fra det, vi er vant til. Udgivelsesdato: Februar...

  8. The chlamydial organism Simkania negevensis forms ER vacuole contact sites and inhibits ER-stress.

    Science.gov (United States)

    Mehlitz, Adrian; Karunakaran, Karthika; Herweg, Jo-Ana; Krohne, Georg; van de Linde, Sebastian; Rieck, Elke; Sauer, Markus; Rudel, Thomas

    2014-08-01

    Most intracellular bacterial pathogens reside within membrane-surrounded host-derived vacuoles. Few of these bacteria exploit membranes from the host's endoplasmic reticulum (ER) to form a replicative vacuole. Here, we describe the formation of ER-vacuole contact sites as part of the replicative niche of the chlamydial organism Simkania negevensis. Formation of ER-vacuole contact sites is evolutionary conserved in the distantly related protozoan host Acanthamoeba castellanii. Simkania growth is accompanied by mitochondria associating with the Simkania-containing vacuole (SCV). Super-resolution microscopy as well as 3D reconstruction from electron micrographs of serial ultra-thin sections revealed a single vacuolar system forming extensive ER-SCV contact sites on the Simkania vacuolar surface. Simkania infection induced an ER-stress response, which was later downregulated. Induction of ER-stress with Thapsigargin or Tunicamycin was strongly inhibited in cells infected with Simkania. Inhibition of ER-stress was required for inclusion formation and efficient growth, demonstrating a role of ER-stress in the control of Simkania infection. Thus, Simkania forms extensive ER-SCV contact sites in host species evolutionary as diverse as human and amoeba. Moreover, Simkania is the first bacterial pathogen described to interfere with ER-stress induced signalling to promote infection. © 2014 John Wiley & Sons Ltd.

  9. Ga flux dependence of Er-doped GaN luminescent thin films

    Science.gov (United States)

    Lee, D. S.; Steckl, A. J.

    2002-02-01

    Er-doped GaN thin films have been grown on (111) Si substrates with various Ga fluxes in a radio frequency plasma molecular beam epitaxy system. Visible photoluminescence (PL) and electroluminescence (EL) emission at 537/558 nm and infrared (IR) PL emission at 1.5 μm from GaN:Er films exhibited strong dependence on the Ga flux. Both visible and IR PL and visible EL increase with the Ga flux up to the stoichiometric growth condition, as determined by growth rate saturation. Beyond this condition, all luminescence levels abruptly dropped to the detection limit with increasing Ga flux. The Er concentration, measured by secondary ion mass spectroscopy and Rutherford backscattering, decreases with increasing Ga flux under N-rich growth conditions and remains constant above the stoichiometric growth condition. X-ray diffraction indicated that the crystalline quality of the GaN:Er film was improved with increasing Ga flux up to stoichiometric growth condition and then saturated. Er ions in the films grown under N-rich conditions appear much more optically active than those in the films grown under Ga-rich conditions.

  10. [Microstructure and spectral property of Er3+ doped transparent oxyfluoride glass ceramics with high fluorine contents].

    Science.gov (United States)

    Lin, Le-Jing; Ren, Guo-Zhong; Chen, Min-Peng; Liu, Yang

    2009-12-01

    The microstructure and spectral properties of Er3+ doped transparent oxyfluoride glass ceramics with high fluorine content were reported. Two samples with the same initial contents (50SiO2-45PbF2-5PbO-1ErF3) were prepared under the different preparation parameters. The final fluorine contents were detected by a fluoride ion selective electrode. The results shows that the final fluorine contents increase by covering crucibles with corundum lid during melt. The samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), absorption spectra and upconversion luminescence spectra. The results show that PbF2 crystals were precipitated in the sample with high fluorine content before heat treatment. And the PbF2 crystals precipitated inside the glass matrix are spherical with diameters of approximately 10-15 nm in size from the high resolution TEM micrograph. The absorption spectra, J-O parameters and the upconversion spectra show that the Er3+ ions were located in crystalline and vitreous mixed states. It is different from the sample with low fluorine content which is completely amorphous. After heat treatment, Er3+ ions that remain in the glassy phase entered into fluoride nanocrystals in the sample with high fluorine content. The fluorine environment decreases non-radiative transfer which eases the upconversion processes. Hence, the upconversion luminescence intensity of Er3+ ions in the high fluorine content sample after heat treatment is much stronger than that in the precursor sample.

  11. The bioceramic implant: evaluation of implant exposures in 419 implants.

    Science.gov (United States)

    Jordan, David R; Klapper, Stephen R; Gilberg, Steven M; Dutton, Jonathan J; Wong, Amy; Mawn, Louise

    2010-01-01

    To compare the rate of exposure in the immediate 3-month postoperative follow-up period with the rate of exposure after the immediate postoperative period in 419 anophthalmic patients with a bioceramic (aluminum oxide) orbital implant. This is a retrospective, clinical case series of 419 patients who received a bioceramic orbital implant. All patients who presented to five oculofacial surgeons (D.J., S.G., J.D., S.K., L.M.) from January 1, 2000, to June 1, 2007, who received a bioceramic orbital implant and had a minimum of 3 months of follow-up were included in this study. The authors analyzed age, gender, type of surgery, implant size, peg system, follow-up duration, time of pegging, and problems encountered. The data from the patients with greater than 3 months of follow-up with exposure of the bioceramic implant are detailed in this report. There were 353 patients followed for 3 to 96 months with an average of 30 months of follow-up (median 23 months). Implant exposure occurred in 32/353 bioceramic implants (9.1%). Six of the 32 (19%) exposures occurred during the 90-day postoperative period (average 2.1 months). Twenty-six (81%) exposures occurred outside of the 90-day postoperative period (average 27.5 months, range 4-82 months). Implant exposures can occur anytime postimplant placement. This review discovered an implant exposure rate of 9.1%, with the majority of the exposures occurring after the postoperative follow-up period. Patients with porous orbital implants should be followed on a long-term basis to detect this complication.

  12. Gas source molecular beam epitaxy and thermal stability of Si{sub 1-x} Ge{sub x}/Si superlattice materials

    Energy Technology Data Exchange (ETDEWEB)

    Zou, L.F.; Acosta-Ortiz, S.E. [Centro de Investigaciones en Optica A.C. Unidad Aguascalientes. Juan de Montoro No. 207. Zona Centro, 20000 Aguascalientes (Mexico); Zou, L.X. [Computer Science Department, Zhongnan University for Nationalities Wuhan, Hubei 430074 (China); Regalado, L.E. [Centro de Investigaciones en Optica, Loma del Bosque No. 115, Loma del Campestre C.P. 37000, Leon, Guanajuato (Mexico); Sun, D.Z.; Wang, Z.G. [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

    1998-12-31

    Gas source molecular beam epitaxy has been used to grow Si{sub 1-x} Ge{sub x} alloys and Si{sub 1-x} Ge{sub x}/Si multi-quantum wells (MQWs) on (100) Si substrates with Si{sub 2}H{sub 6} and GeH{sub 4} as sources. Heterostructures and MQWs with mirror-like surface morphology, good crystalline quality, and abrupt interfaces have been studied by a variety of in situ and ex situ techniques. The structural stability and strain relaxation in Si{sub 1-x} Ge{sub x}/ Si heterostructures have been investigated, and compared to that in the As ion-implanted Si{sub 1-x} Ge{sub x} epilayers. The results show that the strain relaxation mechanism of the non-implanted Si{sub 1-x} Ge{sub x} epilayers is different form that of the As ion-implanted Si{sub 1-x} Ge{sub x} epilayers. (Author)

  13. Facilitative plasma membrane transporters function during ER transit.

    Science.gov (United States)

    Takanaga, Hitomi; Frommer, Wolf B

    2010-08-01

    Although biochemical studies suggested a high permeability of the endoplasmic reticulum (ER) membrane for small molecules, proteomics identified few specialized ER transporters. To test functionality of transporters during ER passage, we tested whether glucose transporters (GLUTs, SGLTs) destined for the plasma membrane are active during ER transit. HepG2 cells were characterized by low-affinity ER transport activity, suggesting that ER uptake is protein mediated. The much-reduced capacity of HEK293T cells to take up glucose across the plasma membrane correlated with low ER transport. Ectopic expression of GLUT1, -2, -4, or -9 induced GLUT isoform-specific ER transport activity in HEK293T cells. In contrast, the Na(+)-glucose cotransporter SGLT1 mediated efficient plasma membrane glucose transport but no detectable ER uptake, probably because of lack of a sufficient sodium gradient across the ER membrane. In conclusion, we demonstrate that GLUTs are sufficient for mediating ER glucose transport en route to the plasma membrane. Because of the low volume of the ER, trace amounts of these uniporters contribute to ER solute import during ER transit, while uniporters and cation-coupled transporters carry out export from the ER, together potentially explaining the low selectivity of ER transport. Expression levels and residence time of transporters in the ER, as well as their coupling mechanisms, could be key determinants of ER permeability.

  14. Kinome wide functional screen identifies role of Polo-like kinase 1 (PLK1) in hormone-independent, ER-positive breast cancer

    Science.gov (United States)

    Bhola, Neil; Jansen, Valerie M.; Bafna, Sangeeta; Giltnane, Jennifer M.; Balko, Justin M.; Estrada, Mónica V.; Meszoely, Ingrid; Mayer, Ingrid; Abramson, Vandana; Ye, Fei; Sanders, Melinda; Dugger, Teresa C.; Van Allen, Eliezer; Arteaga, Carlos L.

    2014-01-01

    Estrogen receptor α (ER)-positive breast cancers initially respond to antiestrogens but eventually become estrogen-independent and recur. ER+ breast cancer cells resistant to long-term estrogen deprivation (LTED) exhibit hormone-independent ER transcriptional activity and growth. A kinome-wide siRNA screen using a library targeting 720 kinases identified Polo-like kinase 1 (PLK1) as one of the top genes whose downregulation resulted in inhibition of estrogen-independent ER transcriptional activity and growth of LTED cells. High PLK1 mRNA and protein correlated with a high Ki67 score in primary ER+ breast cancers after treatment with the aromatase inhibitor letrozole. RNAi-mediated knockdown of PLK1 inhibited ER expression, estrogen-independent growth and ER transcription in MCF7 and HCC1428 LTED cells. Pharmacological inhibition of PLK1 with volasertib, a small molecule ATP-competitive PLK1 inhibitor, decreased LTED cell growth, ER transcriptional activity and ER expression. Volasertib in combination with the ER antagonist, fulvestrant, decreased MCF7 xenograft growth in ovariectomized mice more potently than each drug alone. JUNB, a component of the AP-1 complex, was expressed 16-fold higher in MCF7/LTED compared to parental MCF7 cells. Further, JUNB and BCL2L1 (which encodes anti-apoptotic BCL-xL) mRNA levels were markedly reduced upon volasertib treatment in MCF7/LTED cells while they were increased in parental MCF7 cells. Finally, JUNB knockdown decreased ER expression and transcriptional activity in MCF7/LTED cells, suggesting that PLK1 drives ER expression and estrogen-independent growth via JUNB. These data support a critical role of PLK1 in acquired hormone-independent growth of ER+ human breast cancer and is therefore a promising target in tumors that have escaped estrogen deprivation therapy. PMID:25480943

  15. Implant success!!!.....simplified

    Directory of Open Access Journals (Sweden)

    Luthra Kaushal

    2009-01-01

    Full Text Available The endeavor towards life-like restoration has helped nurture new vistas in the art and science of implant dentistry. The protocol of "restoration-driven implant placement" ensures that the implant is an apical extension of the ideal future restoration and not the opposite. Meticulous pre-implant evaluation of soft and hard tissues, diagnostic cast and use of aesthetic wax-up and radiographic template combined with surgical template can simplify the intricate roadmap for appropriate implant treatment. By applying the harmony of artistic skill, scientific knowledge and clinical expertise, we can simply master the outstanding implant success in requisites of aesthetics, phonetics and function.

  16. Implant success!!!.....simplified.

    Science.gov (United States)

    Luthra, Kaushal K

    2009-01-01

    The endeavor towards life-like restoration has helped nurture new vistas in the art and science of implant dentistry. The protocol of "restoration-driven implant placement" ensures that the implant is an apical extension of the ideal future restoration and not the opposite. Meticulous pre-implant evaluation of soft and hard tissues, diagnostic cast and use of aesthetic wax-up and radiographic template combined with surgical template can simplify the intricate roadmap for appropriate implant treatment.By applying the harmony of artistic skill, scientific knowledge and clinical expertise, we can simply master the outstanding implant success in requisites of aesthetics, phonetics and function.

  17. Study on the Microstructure and Wettability of an Al-Cu-Si Braze Containing Small Amounts of Rare Earth Erbium

    Science.gov (United States)

    Shi, Yaowu; Yu, Yang; Li, Yapeng; Xia, Zhidong; Lei, Yongping; Li, Xiaoyan; Guo, Fu

    2009-04-01

    The effect of adding small amounts of rare earth Er on the microstructure of an Al-Cu-Si braze alloy has been investigated. Several Al-20Cu-7Si braze alloys containing various contents of Er were prepared, and their melting temperature, microstructure, hardness, and wettability in contact with 3003 aluminum alloy substrates were determined. The results indicate that the constituents of the microstructure of Al-20Cu-7Si-Er braze alloys are similar to those in the Al-20Cu-7Si alloy, and comprise of solid solutions of aluminum, silicon, and the intermetallic compound CuAl2. When the Er content increases, the size of the Al phase decreases, and the needle-like Si phase is thickened, and transformed to a blocky shape. Moreover, small amounts of Er can improve the wettability and hardness of the Al-20Cu-7Si braze alloy; however, the melting temperature of the Al-20Cu-7Si alloy does not change.

  18. [Biomaterials in cochlear implants].

    Science.gov (United States)

    Stöver, T; Lenarz, T

    2009-05-01

    Cochlear implants (CI) represent the "gold standard" for the treatment of congenitally deaf children and postlingually deafened adults. Thus, cochlear implantation is a success story of new bionic prosthesis development. Owing to routine application of cochlear implants in adults but also in very young children (below the age of one), high demands are placed on the implants. This is especially true for biocompatibility aspects of surface materials of implant parts which are in contact with the human body. In addition, there are various mechanical requirements which certain components of the implants must fulfil, such as flexibility of the electrode array and mechanical resistance of the implant housing. Due to the close contact of the implant to the middle ear mucosa and because the electrode array is positioned in the perilymphatic space via cochleostomy, there is a potential risk of bacterial transferral along the electrode array into the cochlea. Various requirements that have to be fulfilled by cochlear implants, such as biocompatibility, electrode micromechanics, and although a very high level of technical standards has been carried out there is still demand for the improvement of implants as well as of the materials used for manufacturing, ultimately leading to increased implant performance. General considerations of material aspects related to cochlear implants as well as potential future perspectives of implant development will be discussed.

  19. Ordet er dit DR P1

    DEFF Research Database (Denmark)

    2014-01-01

    Har du brug for en lokal bank? Vestjysk Bank kæmper for livet. Mandag afleverede banken en genopretningsplan til Finanstilsynet, som nu skal beslutte, om man tror, den Lemvig-baserede bank er i stand til at overleve...

  20. ER Consolidated Quarterly Report October 2014

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, John R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-10-01

    This Environmental Restoration Operations (ER) Consolidated Quarterly Report (ER Quarterly Report) provides the status of ongoing corrective actions and related Long- Term Stewardship (LTS) activities being implemented by Sandia National Laboratories, New Mexico (SNL/NM) ER for the April, May, and June 2014 quarterly reporting period. Section 2.0 provides the status of ER Operations activities including closure activities for the Mixed Waste Landfill (MWL), project management and site closure, and hydrogeologic characterizations. Section 3.0 provides the status of LTS activities that relate to the Chemical Waste Landfill (CWL) and the associated Corrective Action Management Unit (CAMU). Section 4.0 provides the references noted in Section I of this report.

  1. Synthesis of nonepitaxial multilayer silicene assisted by ion implantation

    Science.gov (United States)

    Tsai, Hsu-Sheng; Hsiao, Ching-Hung; Chen, Chia-Wei; Ouyang, Hao; Liang, Jenq-Horng

    2016-05-01

    Nonepitaxial multilayer silicene with a lonsdaleite structure was synthesized from a 4H-SiC substrate using an implantation-assisted process. An sp3-like bonding signal was fitted in a lonsdaleite Si XPS spectrum. The multilayer silicene was directly observed and the derived interplanar distances were found to be nearly consistent with the theoretical values.Nonepitaxial multilayer silicene with a lonsdaleite structure was synthesized from a 4H-SiC substrate using an implantation-assisted process. An sp3-like bonding signal was fitted in a lonsdaleite Si XPS spectrum. The multilayer silicene was directly observed and the derived interplanar distances were found to be nearly consistent with the theoretical values. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02274j

  2. Ordering at Si(111)/o-Si and Si(111)/SiO2 Interfaces

    DEFF Research Database (Denmark)

    Robinson, I. K.; Waskiewicz, W. K.; Tung, R. T.

    1986-01-01

    X-ray diffraction has been used to measure the intensity profile of the two-dimensional rods of scattering from a single interface buried inside a bulk material. In both Si(111)/a-Si and Si(111)/SiO2 examples there are features in the perpendicular-momentum-transfer dependence which are not expec......X-ray diffraction has been used to measure the intensity profile of the two-dimensional rods of scattering from a single interface buried inside a bulk material. In both Si(111)/a-Si and Si(111)/SiO2 examples there are features in the perpendicular-momentum-transfer dependence which...... are not expected from an ideal sharp interface. The diffraction profiles are explained by models with partially ordered layers extending into the amorphous region. In the Si(111)/a-Si case there is clear evidence of stacking faults which are attributed to residual 7×7 reconstruction....

  3. $^{31}$Si Self-Diffusion in Si-Ge Alloys and Si-(B-)C-N Ceramics and Diffusion Studies for Al and Si Beam Developments

    CERN Multimedia

    Nylandsted larsen, A; Voss, T L; Strohm, A

    2002-01-01

    An invaluable method for studying diffusion in solids is the radiotracer technique. However, its applicability had been restricted to radiotracer atoms with half-lives $t_{1/2}$ of about 1~d or longer. Within the framework of IS372 a facility was developed in which short-lived radiotracer atoms ( 5min $\\scriptstyle{\\lesssim}$ $t_{1/2}\\scriptstyle{\\lesssim}$1 d ) can be used. For the implantation of the short-lived tracers the facility is flanged to the ISOLDE beamline, and all post-implantation steps required in the radiotracer technique are done in situ.\\\\ After successful application of this novel technique in diffusion studies of $^{11}$C ($t_{1/2}$ = 20.3 min), this experiment aims at performing self-diffusion studies of $^{31}$Si ($t_{1/2}$ = 2.6~h) in Si--Ge alloys and in amorphous Si--(B--)C--N ceramics.\\\\ Our motivation for measuring diffusion in Si--Ge alloys is their recent technological renaissance as well as the purpose to test the prediction that in these alloys the self-diffusion mechanism chang...

  4. Hvilke Dødehavstekster er "sekteriske"?

    DEFF Research Database (Denmark)

    Holst, Søren

    2003-01-01

    Skønt Dødehavsrullerne antageligt tilhørte en gruppering, der boede i Qumran, tyder alt på, at mange af teksterne er forfattet andre steder. Artiklen undersøger den særlige sprogbrug, som antageligt er typisk for Qumran-samfundet, og som præger forbavsende få af tekserne. En meget stor del af tek...

  5. Er dansk kornkvalitet rent til rotterne?

    DEFF Research Database (Denmark)

    Dubgaard, Alex

    2016-01-01

    Målinger viser, at der har været et vist fald i kornets indhold af protein, men de påståede negative konsekvenser er stærkt overdrevne. Påstanden om at dansk korn er så ringe, at byggerier og brødproducenter må hente deres varer i udlandet, holder ikke stik....

  6. Trump er godt nyt for verdensfreden

    DEFF Research Database (Denmark)

    Jakobsen, Peter Viggo

    2017-01-01

    Trumps uberegnelighed øger ikke risikoen for krig. Den mindsker den ved at få de allierede til at gøre mere og modstanderne til at forhandle. Det er godt for verdensfreden......Trumps uberegnelighed øger ikke risikoen for krig. Den mindsker den ved at få de allierede til at gøre mere og modstanderne til at forhandle. Det er godt for verdensfreden...

  7. Håndbold er en praksis!

    DEFF Research Database (Denmark)

    Olsen, Poul Bitsch

    2008-01-01

    Dansk håndbold er en kæmpemæssig succeshistorie. Ser man snævert på den udvikling, elitedelen af sporten har gennemlevet de seneste 15 år, viser stort set alle tænkelige parametre fremgang. De internationale resultater for lands og klubhold er med få udfald blevet stadigt bedre, omsætningen i klu...

  8. Arctigenin alleviates ER stress via activating AMPK

    Science.gov (United States)

    Gu, Yuan; Sun, Xiao-xiao; Ye, Ji-ming; He, Li; Yan, Shou-sheng; Zhang, Hao-hao; Hu, Li-hong; Yuan, Jun-ying; Yu, Qiang

    2012-01-01

    Aim: To investigate the protective effects of arctigenin (ATG), a phenylpropanoid dibenzylbutyrolactone lignan from Arctium lappa L (Compositae), against ER stress in vitro and the underlying mechanisms. Methods: A cell-based screening assay for ER stress regulators was established. Cell viability was measured using MTT assay. PCR and Western blotting were used to analyze gene and protein expression. Silencing of the CaMKKβ, LKB1, and AMPKα1 genes was achieved by RNA interference (RNAi). An ATP bioluminescent assay kit was employed to measure the intracellular ATP levels. Results: ATG (2.5, 5 and 10 μmol/L) inhibited cell death and unfolded protein response (UPR) in a concentration-dependent manner in cells treated with the ER stress inducer brefeldin A (100 nmol/L). ATG (1, 5 and 10 μmol/L) significantly attenuated protein synthesis in cells through inhibiting mTOR-p70S6K signaling and eEF2 activity, which were partially reversed by silencing AMPKα1 with RNAi. ATG (1-50 μmol/L) reduced intracellular ATP level and activated AMPK through inhibiting complex I-mediated respiration. Pretreatment of cells with the AMPK inhibitor compound C (25 μmol/L) rescued the inhibitory effects of ATG on ER stress. Furthermore, ATG (2.5 and 5 μmol/L) efficiently activated AMPK and reduced the ER stress and cell death induced by palmitate (2 mmol/L) in INS-1 β cells. Conclusion: ATG is an effective ER stress alleviator, which protects cells against ER stress through activating AMPK, thus attenuating protein translation and reducing ER load. PMID:22705729

  9. Hvad litteraturen kan, er ofte det rigtige ..

    DEFF Research Database (Denmark)

    Bundsgaard, Jeppe; Kühn, Lisbet

    2010-01-01

    Læsning i dansk handler i første omgang om at blive god til at læse, men på mellemtrinnet er det ved at være tiden til også at bruge skønlitteraturen til det, den er god til, nemlig til at få indsigt i menneskelivets kompleksitet. I dette kapitel anbefales det at gøre noget med litteraturen, fx f...

  10. Snip snap snude - dobbelthagerne er ude

    DEFF Research Database (Denmark)

    Larsen, Malene Charlotte; Kofoed, Jette

    2015-01-01

    Det handler om at være grim. Det står i skarp kontrast til det pæne og polerede på Instagram. Det er flygtigt, useriøst og ligegyldigt. Og så forsvinder det heldigvis igen, så man behøver kun at forholde sig til det i de få sekunder, det foregår. Snapchat vokser i popularitet og er nu det...

  11. High conductivity, shallow doping in silicon by ion implantation and furnace annealing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, S.; Hodel, M.W.; Samadpour, F. (Motorola, Inc., Phoenix, AZ (USA). Solar Energy Research and Development Dept.; Motorola, Inc., Phoenix, AZ (USA). Semiconductor Group)

    1985-01-01

    High dose, shallow implants (proportional 0.2 ..mu..m) were furnace annealed. As expected, As/sup +/ and P/sup +/ implants showed the same annealing characteristics. Both can be activated to their maximum levels at 550/sup 0/C; but P/sup +/ implant gave higher conductivity than As/sup +/ implant. BF/sup +//sub 2/ implant gave better activation than B/sup +/ implant at anneal temperatures below 900/sup 0/C; but both require additional moderate dose Si/sup +/ implant with proper energy and implant sequence to achieve maximum activation at these low temperatures. Maximum activation with minimum diffusion and acceptable junction leakage for VLSIC applications can be achieved by conventional furnace annealing technology.

  12. Characterization of the ER-Targeted Low Affinity Ca2+ Probe D4ER

    Directory of Open Access Journals (Sweden)

    Elisa Greotti

    2016-09-01

    Full Text Available Calcium ion (Ca2+ is a ubiquitous intracellular messenger and changes in its concentration impact on nearly every aspect of cell life. Endoplasmic reticulum (ER represents the major intracellular Ca2+ store and the free Ca2+ concentration ([Ca2+] within its lumen ([Ca2+]ER can reach levels higher than 1 mM. Several genetically-encoded ER-targeted Ca2+ sensors have been developed over the last years. However, most of them are non-ratiometric and, thus, their signal is difficult to calibrate in live cells and is affected by shifts in the focal plane and artifactual movements of the sample. On the other hand, existing ratiometric Ca2+ probes are plagued by different drawbacks, such as a double dissociation constant (Kd for Ca2+, low dynamic range, and an affinity for the cation that is too high for the levels of [Ca2+] in the ER lumen. Here, we report the characterization of a recently generated ER-targeted, Förster resonance energy transfer (FRET-based, Cameleon probe, named D4ER, characterized by suitable Ca2+ affinity and dynamic range for monitoring [Ca2+] variations within the ER. As an example, resting [Ca2+]ER have been evaluated in a known paradigm of altered ER Ca2+ homeostasis, i.e., in cells expressing a mutated form of the familial Alzheimer’s Disease-linked protein Presenilin 2 (PS2. The lower Ca2+ affinity of the D4ER probe, compared to that of the previously generated D1ER, allowed the detection of a conspicuous, more clear-cut, reduction in ER Ca2+ content in cells expressing mutated PS2, compared to controls.

  13. Recubrimientos antibacterianos basados en silicio para implantes dentales

    OpenAIRE

    Pallá Rubio, Beatriz

    2016-01-01

    232 p. El uso de implantes dentales en odontología está tan extendido hoy en día, que ya nadie discute su relevancia. Su tasa de éxitos es elevada (debido al criterio de selección de pacientes), si bien un porcentaje cercano al 10% de los implantes debe ser eliminado, por problemas de osteointegración, o por la aparición de infecciones, considerándose esto último hoy en día, la principal causa del fallo de los implantes dentales. Sin embargo, una gran parte de la investigación destinada a ...

  14. Implantable Medical Devices

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Implantable Medical Devices Updated:Sep 16,2016 For Rhythm Control ... a Heart Attack Introduction Medications Surgical Procedures Implantable Medical Devices • Life After a Heart Attack • Heart Attack ...

  15. Possibility of Mg- and Ca-based intermetallic compounds as new biodegradable implant materials.

    Science.gov (United States)

    Hagihara, Koji; Fujii, Kenta; Matsugaki, Aira; Nakano, Takayoshi

    2013-10-01

    Mg- or Ca-based intermetallic compounds of Mg2Ca, Mg2Si, Ca2Si and CaMgSi are investigated as possible new candidates for biodegradable implant materials, attempting to improve the degradation behavior compared to Mg and Ca alloys. The reactivity of Ca can be indeed reduced by the formation of compounds with Mg and Si, but its reactivity is still high for applications as an implant material. In contrast, Mg2Si shows a higher corrosion resistance than conventional Mg alloys while retaining biodegradability. In cytotoxicity tests under the severe condition conducted in this study, both pure Mg and Mg2Si showed relatively high cytotoxicity on preosteoblast MC3T3-E1. However, the cell viability cultured in the Mg2Si extract medium was confirmed to be better than that in a pure Mg extract medium in all the conditions investigated with the exception of the 10% extract medium, because of the lower corrosion rate of Mg2Si. The cytotoxicity derived from the Si ion was not significantly detected in the Mg2Si extract medium in the concentration level of ~70 mg/l measured in the present study. For aiming the practical application of Mg2Si as an implant material, however, its brittle nature must be improved. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Implantable electronic medical devices

    CERN Document Server

    Fitzpatrick, Dennis

    2014-01-01

    Implantable Electronic Medical Devices provides a thorough review of the application of implantable devices, illustrating the techniques currently being used together with overviews of the latest commercially available medical devices. This book provides an overview of the design of medical devices and is a reference on existing medical devices. The book groups devices with similar functionality into distinct chapters, looking at the latest design ideas and techniques in each area, including retinal implants, glucose biosensors, cochlear implants, pacemakers, electrical stimulation t

  17. Electrochemical doping of mesoporous silicon with Er: the effect of the current intensity

    Energy Technology Data Exchange (ETDEWEB)

    Mula, Guido, E-mail: guido.mula@unica.it [Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, S.P. 8 km 0.700, 09042 Cagliari (Italy); Pinna, Elisa [Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, S.P. 8 km 0.700, 09042 Cagliari (Italy); Falqui, Andrea [Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, S.P. 8 km 0.700, 09042 Cagliari (Italy); Ruffilli, Roberta [Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, S.P. 8 km 0.700, 09042 Cagliari (Italy); Palmas, Simonetta; Mascia, Michele [Dipartimento di Ingegneria Meccanica Chimica e dei Materiali, Università degli Studi di Cagliari, Piazza d’Armi, 09126 Cagliari (Italy)

    2014-08-30

    Graphical abstract: - Highlights: • A multidisciplinary approach on porous Si electrochemical Er doping is proposed. • The phenomena taking place at the large developed surface of porous silicon are studied. • Electrochemical, optical and structural characterizations are used. • The early stages of doping are studied by electrochemical impedance spectroscopy. • The dependence of the final amount of Er deposited on the current intensity and not only on the transferred charge is shown. - Abstract: There is an ongoing intense research for cost-effective Er-doped Si-based light-emitting devices at the 1.5 μm wavelength. The efficient electrochemical Er-doping of porous silicon for this purpose requires a good understanding of the phenomena involved, since those taking place at the pores inner surface control the doping process. However, almost no attention has been given, to date, to the relevant effects of the current intensity onto the doping results. In this work, the effect of the current intensity on the doping process is explored by means of electrochemical impedance spectroscopy, optical reflectivity and energy dispersive spectrometry via scanning electron microscopy. The combined analysis of all results strongly suggests that the formation of a gel-like Er ethanolate, unaffected by changes in the sample thickness, occurs from the very first stages of the doping process. Moreover, while for constant current doping processes we show that, under any given doping condition, the doping level is proportional to the transferred charge, we demonstrate that performing the doping process using different current intensities may lead to dramatically different results.

  18. Enhanced Physicochemical and Biological Properties of Ion-Implanted Titanium Using Electron Cyclotron Resonance Ion Sources

    Directory of Open Access Journals (Sweden)

    Csaba Hegedűs

    2016-01-01

    Full Text Available The surface properties of metallic implants play an important role in their clinical success. Improving upon the inherent shortcomings of Ti implants, such as poor bioactivity, is imperative for achieving clinical use. In this study, we have developed a Ti implant modified with Ca or dual Ca + Si ions on the surface using an electron cyclotron resonance ion source (ECRIS. The physicochemical and biological properties of ion-implanted Ti surfaces were analyzed using various analytical techniques, such as surface analyses, potentiodynamic polarization and cell culture. Experimental results indicated that a rough morphology was observed on the Ti substrate surface modified by ECRIS plasma ions. The in vitro electrochemical measurement results also indicated that the Ca + Si ion-implanted surface had a more beneficial and desired behavior than the pristine Ti substrate. Compared to the pristine Ti substrate, all ion-implanted samples had a lower hemolysis ratio. MG63 cells cultured on the high Ca and dual Ca + Si ion-implanted surfaces revealed significantly greater cell viability in comparison to the pristine Ti substrate. In conclusion, surface modification by electron cyclotron resonance Ca and Si ion sources could be an effective method for Ti implants.

  19. Upconversion and tribological properties of β-NaYF{sub 4}:Yb,Er film synthesized on silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chuanying [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Cheng, Xianhua, E-mail: xhcheng@sjtu.edu.cn [School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2016-05-15

    Highlights: • β-NaYF{sub 4}:Yb,Er upconversion (UC) film was synthesized on silicon substrate. • Tribological test was used to qualitatively evaluate the adhesion of the UC film. • The UC film was combined with Si substrate by covalent chemical bonds. • The method used in this work can be applicable for other UC films. - Abstract: In this work, β-NaYF{sub 4}:Yb,Er upconversion (UC) film was successfully prepared on silicon (Si) substrate via self-assemble method for the first time. The chemical composition and surface morphology of the UC film were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), X-ray power diffraction (XRD), and scanning electron microscopy (SEM) measurements. To investigate the effects of KH-560 primer film and chemical reactions on the UC luminescence properties of β-NaYF{sub 4}:Yb,Er UC film, decay profiles of the 540 nm and 655 nm radiations were measured. Furthermore, tribological test was applied to qualitatively evaluate the adhesion of the UC film. The results indicate that the UC film has been successfully prepared on Si substrate by covalent chemical bonds. This work provides a facile way to synthesize β-NaYF{sub 4}:Yb,Er UC film with robust adhesion to the substrate, which can be applicable for other UC films.

  20. Efterlønnernes helbred er nu ok

    DEFF Research Database (Denmark)

    Jørgensen, Michael; Høgelund, Jan; Brink Thomsen, Lars

    2011-01-01

    føler, at man har et decideret dårligt helbred eller er nedslidt". Ja, men det er jo ikke ensbetydende med, at man ikke er i stand til at arbejde. Faktisk er der mange med helbredsproblemer, som arbejder: I 2010 var knap halvdelen af de ca. 560.000 personer, som oplyser, at de har et handicap eller...

  1. Complication Rates Observed in Silicone and Polyurethane Catheters of Totally Implanted Central Venous Access Devices Implanted in the Upper Arm.

    Science.gov (United States)

    Busch, Jasmin D; Vens, Maren; Mahler, Catherine; Herrmann, Jochen; Adam, Gerhard; Ittrich, Harald

    2017-08-01

    To present frequency and types of complications related to silicone (SI) versus polyurethane (PUR) catheters of totally implanted venous access devices (TIVADs) placed in the upper arm. A cohort of 2,491 consecutive patients with TIVADs implanted between 2006 and 2015 was retrospectively analyzed. Complications were classified according to SIR guidelines. Pearson χ 2 test was used for categorical variables, and Student t test was used for continuous variables. Nominal P values were reported, and 2-sided P values catheter, and 1,732 had a PUR catheter. Total dwell time was 584,853 catheter days. Mean total complication rate was 12.25% (SI, 14.87%; PUR, 11.43%; P = .040). Subanalysis revealed significant differences for material failures (eg, catheter fracture [SI, 3.35%; PUR, 0.06%; P catheter occlusion/venous thromboses [SI, 2.79%/0.74%; PUR, 1.33%/3.17%; P catheter-related sepsis [SI, 4.64%; PUR, 4.68%; P = 1]) or other nonthrombotic dysfunctions (eg, catheter detachment, line migration, wound dehiscence [SI, 3.35%; PUR, 2.19%; P = .179]). The reported data suggest different risk profiles in SI catheters compared with PUR catheters, with more material failures and thrombotic catheter occlusions in SI catheters and more venous thromboses in PUR catheters. Copyright © 2017 SIR. Published by Elsevier Inc. All rights reserved.

  2. Rehabilitación sobre implantes oseointegrados A case with rehabilitation on boneintegrated implants

    Directory of Open Access Journals (Sweden)

    Leticia María Lemus Cruz

    2009-03-01

    Full Text Available Se presenta un caso de un paciente rehabilitado en la consulta de Implantología de la Facultad de Estomatología de Ciudad de La Habana. La historia de la implantología moderna se remonta a principios de los años 60, cuando Per-Ingvar Branemark sienta las bases de la osteointegración y describe los primeros implantes de titanio con forma de tornillo. Aunque antigua, es la prótesis más moderna. Si la meticulosidad es obligada en la elaboración de todo tipo de prótesis, en los trabajos de implantes no se admite el más mínimo fallo, desde la planificación del caso hasta la implantación de la prótesis en boca. Para obtener buenos resultados, las técnicas y los procesos han de observarse escrupulosamente. En nuestra Facultad se ha creado el Grupo de Implantología, que es el encargado de la colocación de implantes y la rehabilitación prótesica de estos. Para ello han sido utilizado diferentes tipos de implantes comercializados y patentizados al nivel mundial. Se reafirma que la rehabilitación sobre implantes mejora la calidad estética y funcional de los pacientes.A case of rehabilitation patient is presented seen in Implantation Science consulting room of Stomatology Faculty of Havana City. History of implantation science dates back to at the beginning of 60s, when Per-Ingvar Branemark creates the bases of bone-integration and to describe the firsts titanium implants in a screw form. Although ancient, it is the more modern prosthesis. If meticulousness if mandatory in elaboration of all type of prosthesis, in implants works it inadmissible the minimum of failure, from the case planning until prosthesis implantation in mouth. To achieve good results, techniques and processes has to be scrupulously observed. In our Faculty it has been created a group of Implantation Science, which is in charge of implants placement, and of the prosthetic rehabilitation of these. Thus, we used different types of marketed and showed at world level. It

  3. Optical waveguides in Er:LiNbO3 fabricated by different techniques - A comparison

    Science.gov (United States)

    Cajzl, Jakub; Nekvindová, Pavla; Macková, Anna; Malinský, Petr; Oswald, Jiří; Staněk, Stanislav; Vytykáčová, Soňa; Špirková, Jarmila

    2016-03-01

    We report on the comparison of three techniques used for the fabrication of optical waveguides in erbium doped lithium niobate crystal substrates (Er:LiNbO3). The techniques include ion in-diffusion from a titanium metal layer, annealed proton exchange (APE), and He+ ion implantation. The main focus of the work was placed on the investigation of the influence of the used optical waveguides fabrication techniques on the structural and luminescence properties of Er:LiNbO3 substrates. The results have shown that none of the used optical-waveguide-fabrication techniques significantly affect the position of erbium in the host crystal structure. It turned out, however, that the fabrication process affected luminescence intensities of the characteristic luminescence bands of erbium ions - the most significant decrease in the luminescence intensity was observed in the Ti-indiffused waveguides.

  4. Diagnostic Imaging for Implants

    Directory of Open Access Journals (Sweden)

    Sanjay M Mallya

    2004-01-01

    Full Text Available Dental implants are a popular modality for permanent tooth replacement. The key to successful implant placement, its subsequent osseointegration and the final prosthetic rehabilitation is proper preoperative assessment. Diagnostic imaging plays an important role in the pre- and post-surgical evaluation process. Imaging is used to evaluate suitability of implant sites, aid in selection of appropriate implants, and finally evaluate implant placement and osseointegration. This article reviews the role of diagnostic imaging in the various phases and the advantages and limitations of the numerous imaging modalities.

  5. Ultrafast Generation of Unconventional {001 } Loops in Si

    Science.gov (United States)

    Marqués, Luis A.; Aboy, María; Santos, Iván; López, Pedro; Cristiano, Fuccio; La Magna, Antonino; Huet, Karim; Tabata, Toshiyuki; Pelaz, Lourdes

    2017-11-01

    Ultrafast laser annealing of ion implanted Si has led to thermodynamically unexpected large {001 } self-interstitial loops, and the failure of Ostwald ripening models for describing self-interstitial cluster growth. We have carried out molecular dynamics simulations in combination with focused experiments in order to demonstrate that at temperatures close to the melting point, self-interstitial rich Si is driven into dense liquidlike droplets that are highly mobile within the solid crystalline Si matrix. These liquid droplets grow by a coalescence mechanism and eventually transform into {001 } loops through a liquid-to-solid phase transition in the nanosecond time scale.

  6. TYPES OF WOMAN IN ER TABILDI EPIC / ER TABILDI DESTANINDA KADIN TİPLER

    Directory of Open Access Journals (Sweden)

    Ahmet SAÇKESEN (M.A.H.

    2007-08-01

    Full Text Available Importance and function of Turkish woman will be analyzed during historical process in this article named as “Types of Woman in Er Tabıldı Epic” Types of woman in Er Tabıldı Legend will be explained as ideal wife and mother types ideal lover and assistant types.

  7. Det er ikke længere samfundet skyld

    DEFF Research Database (Denmark)

    Nielsen, Jens Christian; Sørensen, Niels Ulrik

    2011-01-01

    'Det er mig, den er gal med. Jeg må tage mig sammen'. Sådan reagerer unge, når de møder modgang. Offermentaliteten er væk. Troen på det individuelle ansvar råder. For de skrøbeligste er resultatet destruktiv selvbebrejdelse. Det viser forskningsprojetet Når det er svært at være i ung i DK....

  8. Direct Reprogramming of Human Dermal Fibroblasts Into Endothelial Cells Using ER71/ETV2.

    Science.gov (United States)

    Lee, Sangho; Park, Changwon; Han, Ji Woong; Kim, Ju Young; Cho, Kyuwon; Kim, Eun Jae; Kim, Sangsung; Lee, Shin-Jeong; Oh, Se Yeong; Tanaka, Yoshiaki; Park, In-Hyun; An, Hyo Jae; Shin, Claire Min; Sharma, Shraya; Yoon, Young-Sup

    2017-03-03

    Direct conversion or reprogramming of human postnatal cells into endothelial cells (ECs), bypassing stem or progenitor cell status, is crucial for regenerative medicine, cell therapy, and pathophysiological investigation but has remained largely unexplored. We sought to directly reprogram human postnatal dermal fibroblasts to ECs with vasculogenic and endothelial transcription factors and determine their vascularizing and therapeutic potential. We utilized various combinations of 7 EC transcription factors to transduce human postnatal dermal fibroblasts and found that ER71/ETV2 (ETS variant 2) alone best induced endothelial features. KDR+ (kinase insert domain receptor) cells sorted at day 7 from ER71/ETV2-transduced human postnatal dermal fibroblasts showed less mature but enriched endothelial characteristics and thus were referred to as early reprogrammed ECs (rECs), and did not undergo maturation by further culture. After a period of several weeks' transgene-free culture followed by transient reinduction of ER71/ETV2, early rECs matured during 3 months of culture and showed reduced ETV2 expression, reaching a mature phenotype similar to postnatal human ECs. These were termed late rECs. While early rECs exhibited an immature phenotype, their implantation into ischemic hindlimbs induced enhanced recovery from ischemia. These 2 rECs showed clear capacity for contributing to new vessel formation through direct vascular incorporation in vivo. Paracrine or proangiogenic effects of implanted early rECs played a significant role in repairing hindlimb ischemia. This study for the first time demonstrates that ER71/ETV2 alone can directly reprogram human postnatal cells to functional, mature ECs after an intervening transgene-free period. These rECs could be valuable for cell therapy, personalized disease investigation, and exploration of the reprogramming process. © 2016 American Heart Association, Inc.

  9. Enhancing Hydrogen Diffusion in Silica Matrix by Using Metal Ion Implantation to Improve the Emission Properties of Silicon Nanocrystals

    Directory of Open Access Journals (Sweden)

    J. Bornacelli

    2014-01-01

    Full Text Available Efficient silicon-based light emitters continue to be a challenge. A great effort has been made in photonics to modify silicon in order to enhance its light emission properties. In this aspect silicon nanocrystals (Si-NCs have become the main building block of silicon photonic (modulators, waveguide, source, and detectors. In this work, we present an approach based on implantation of Ag (or Au ions and a proper thermal annealing in order to improve the photoluminescence (PL emission of Si-NCs embedded in SiO2. The Si-NCs are obtained by ion implantation at MeV energy and nucleated at high depth into the silica matrix (1-2 μm under surface. Once Si-NCs are formed inside the SiO2 we implant metal ions at energies that do not damage the Si-NCs. We have observed by, PL and time-resolved PL, that ion metal implantation and a subsequent thermal annealing in a hydrogen-containing atmosphere could significantly increase the emission properties of Si-NCs. Elastic Recoil Detection measurements show that the samples with an enhanced luminescence emission present a higher hydrogen concentration. This suggests that ion metal implantation enhances the hydrogen diffusion into silica matrix allowing a better passivation of surface defects on Si NCs.

  10. Hydrocodone Bitartrate ER (Hysingla® ER): A Review in Chronic Pain.

    Science.gov (United States)

    Dhillon, Sohita

    2016-11-01

    Hydrocodone bitartrate extended-release (Hysingla® ER; referred to hereafter as hydrocodone ER) was the first single-entity hydrocodone formulation recognized by the US FDA as having abuse-deterrent properties. It is indicated for the management of pain severe enough to require daily, around-the-clock, long-term opioid treatment and for which alternative treatment options are inadequate. Once-daily oral hydrocodone ER provides consistent plasma hydrocodone concentrations and sustained analgesia over the 24-h dosing interval. Its physicochemical properties render hydrocodone ER harder to manipulate physically, which is expected to deter intranasal, intravenous and oral abuse. For instance, oral hydrocodone ER (intact or chewed) significantly reduced drug liking relative to hydrocodone solution in a clinical study. In two large phase III studies in patients with chronic pain, hydrocodone ER reduced pain intensity, with its effects seen early (during dose titration) and maintained during ≤76 weeks' treatment. During maintenance therapy, the majority of patients continued hydrocodone ER at the dosage achieved at the end of dose titration and without requiring increased doses of supplemental pain medication, suggesting adequate pain management. Hydrocodone ER was generally well tolerated, with a safety profile consistent with that seen with other μ-opioid analgesics. However, like other opioids, it is associated with risks of addiction, abuse/misuse and serious adverse events (AEs), including respiratory depression, withdrawal, physical dependence and overdose. Although large postmarketing studies are needed to determine whether the abuse-deterrent properties of hydrocodone ER result in meaningful reductions in abuse, misuse and related adverse clinical outcomes, current evidence indicates that hydrocodone ER is a useful treatment option for patients with chronic pain.

  11. Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

    Energy Technology Data Exchange (ETDEWEB)

    Ozcan, Ahmet S., E-mail: asozcan@us.ibm.com [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Lavoie, Christian; Jordan-Sweet, Jean [IBM T. J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598 (United States); Alptekin, Emre; Zhu, Frank [IBM Semiconductor Research and Development Center, 2070 Route 52, Hopewell Junction, New York 12533 (United States); Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M. [TEL Epion Inc., 900 Middlesex Turnpike, Bldg. 6, Billerica, Massachusetts 01821 (United States)

    2016-04-21

    We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

  12. Hydrogen- and helium-implanted silicon: Low-temperature positron-lifetime studies

    DEFF Research Database (Denmark)

    Mäkinen, S.; Rajainmäki, H.; Linderoth, Søren

    1991-01-01

    High-purity single-crystal samples of float-zoned Si have been implanted with 6.95-MeV protons and with 25-MeV 3He2 ions at 15 K, and the positron-lifetime technique has been used to identify the defects created in the samples, and to study the effects of H and He on the annealing of point defects...... in Si. The results have been compared with those of proton-irradiated Si. A 100–300-K annealing stage was clearly observed in hydrogen (H+) -implanted Si, and this stage was almost identical to that in the p-irradiated Si. The final annealing state of the H+-implanted Si started at about 400 K......, and it is connected to annealing out of negatively charged divacancy-oxygen pairs. This stage was clearly longer than that for the p-irradiated Si, probably due to the breakup of Si-H bonds at about 550 K. The 100-K annealing stage was not seen with the He-implanted samples. This has been explained by assuming...

  13. Sport er hverken sundt eller social

    DEFF Research Database (Denmark)

    Andersen, Tem Frank

    2013-01-01

    Jeg deler ikke Lasch og Kayser Nielsens konklusioner, selvom jeg er meget enig i, at sport er dirty business. Min analyse peger i den retning, at sporten i sin organiserede form ikke er eller kan fungere som leverandør af nogen ”pakkeløsning”. Men sport kan sagtens bidrage med brudstykker til noget...... meningsfuldt, for det enkelte menneske, eller det enkelte lokalsamfund. Sporten kan ikke længere, hvis den skal fremstå som noget ideal, levere en hel pakke, en fuldstændig myte med tilhørende ritualer. Sport kan imidlertid som projekt fortsat godt levere stof til den meningsskabende fortælling om identitet...

  14. Encapsulation and Implantation Studies of InP.

    Science.gov (United States)

    1982-07-01

    ENCAPSULATION AND IMPLANTATION STUDIES OF InP Technical Report 6. PERFORMING OnRG PR NMC R-958; UILU-ENG 82-2224 7. AUTNOR(s) 6. CONTRACT OR GRANT NUMSER(a...as is a weak reaction of Si with InP. The lack of adequate entropy data - prevented them from taking into account the temperature dependent entropy

  15. ARM CLASIC ER2 CRS/EDOP

    Energy Technology Data Exchange (ETDEWEB)

    Gerald Heymsfield

    2010-12-20

    Data was taken with the NASA ER-2 aircraft with the Cloud Radar System and other instruments in conjunction with the DOE ARM CLASIC field campaign. The flights were near the SGP site in north Central Oklahoma and targeted small developing convection. The CRS is a 94 GHz nadir pointing Doppler radar. Also on board the ER-2 was the Cloud Physics Lidar (CPL). Seven science flights were conducted but the weather conditions did not cooperate in that there was neither developing convection, or there was heavy rain.

  16. Green luminescence and excited state thermalization in Er-doped gallium nitride

    Energy Technology Data Exchange (ETDEWEB)

    Seo, J. T.; Hoemmerich, U. H. [Hampton University, Hampton, VA (United States); Steckl, A. J.; Birkhahn, B. R. [University of Cincinnati, Cincinnatii, OH (United States); Zavada, J. M. [US Army European Research Office, London (United Kingdom)

    2006-09-15

    The optical properties in the {sup 2}H{sub 11/2} and {sup 4}S{sub 3/2} to {sup 4}I{sub 15/2} channels of Er-doped GaN have been investigated. The GaN:Er was grown on Si substrates by solid-source molecular beam epitaxy. The resulting Er concentration was {approx}2 x 10{sup 20} cm{sup -3}, and the unintentional oxygen impurity was observed to be {approx}10{sup 20} cm{sup -3}. Optical spectroscopy revealed that the lifetime decay at the {sup 4}S{sub 3/2} state was mainly due to a strong thermalization between the {sup 2}H{sub 11/2} and the {sup 4}S{sub 3/2} states. The green luminescence ({sup 4}S{sub 3/2} and {sup 2}H{sub 11/2} {yields} {sup 4}I{sub 15/2}) efficiency at 300 K was much higher than 56 %. Photoluminescence and lifetime measurements with different excitation channels suggest the existence of multiple Er-sites in GaN.

  17. Alternating current thin-film electroluminescence of GaN:Er

    Science.gov (United States)

    Heikenfeld, J.; Steckl, A. J.

    2000-11-01

    Thin-film electroluminescence has been obtained from GaN:Er deposited directly on amorphous dielectric layers. Electroluminescent device (ELD) structures consisting of metal/dielectric/GaN:Er/dielectric were fabricated on p+-Si substrates. In contrast to previous GaN:Er ELDs which used epitaxial growth conditions on crystalline substrates and were operated under direct current bias, these ELDs were operated under alternating current bias. Under bias conditions of 170 peak voltage (Vp) and frequencies of 10 and 100 kHz, the ELDs exhibit a luminance of 50 and 300 cd/m2, respectively. The emission spectra, which originate from Er3+ 4f-4f transitions, consist of dominant green emission at ˜537/558 nm accompanied by violet (415 nm) and infrared (1.5 μm) peaks. The violet emission peak indicates that hot carriers can gain up to ˜3 eV energy for a Vp corresponding to 1.5 MV/cm applied field. The emitted intensity initially increases linearly with frequency, followed by a trend towards saturation. The frequency for 3 dB reduction from the linear relation is at ˜65 kHz for the visible emission and ˜8 kHz for the infrared emission.

  18. Caries inhibition potential of Er:YAG and Er:YSGG laser radiation

    Science.gov (United States)

    Fried, Daniel; Featherstone, John D. B.; Visuri, Steven R.; Seka, Wolf D.; Walsh, Joseph T., Jr.

    1996-04-01

    Dental hard tissues can be ablated efficiency by (lambda) equals 3 micrometers laser irradiation with minimal subsurface thermal damage. However, the potential of lasers operating in the region of the infrared for caries preventive treatments has not been investigated. In this study, the caries inhibition potential of Er:YAG ((lambda) equals 2.94 micrometers ) and Er:YSGG ((lambda) equals 2.79 micrometers ) laser radiation on dental enamel was evaluated at various irradiation intensities. Pulsed IR radiometry and scanning electron microscopy (SEM) were used to measure the time-resolved surface temperatures during laser irradiation and to detect changes in the surface morphology. The magnitude and temporal evolution of the surface temperature during multiple pulse irradiation of the tissue was dependent on the wavelength, irradiation intensity, and the number of laser pulses. Radiometry and SEM micrographs indicated that ablation was initiated at temperatures of approximately 300 degree(s)C for Er:YAG and 800 degree(s)C for Er:YSGG laser irradiation, well below the melting and vaporization temperatures of the carbonated hydroxyapatite mineral component (m.p. equals 1200 degree(s)C). Nevertheless, there was marked caries inhibition for irradiation intensities below those temperature thresholds, notably 60% and 40% inhibition was achieved after Er:YSGG and Er:YAG laser irradiation, respectively. These results indicate that the Er:YSGG laser can be used effectively for both preventive dental treatments and for hard tissue removal.

  19. Effects of cesium ion-implantation on mechanical and electrical properties of organosilicate low-k films

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.; Pei, D.; Guo, X.; Cheng, M. K.; Lee, S.; Shohet, J. L. [Plasma Processing and Technology Laboratory, Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Lin, Q. [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States); King, S. W. [Intel Corporation, Hillsboro, Oregon 97124 (United States)

    2016-05-16

    The effects of cesium (Cs) ion-implantation on uncured plasma-enhanced chemical-vapor-deposited organosilicate low dielectric constant (low-k) (SiCOH) films have been investigated and compared with an ultraviolet (UV) cured film. The mechanical properties, including the elastic modulus and hardness, of the SiCOH low-k films are improved by up to 30% with Cs implantation, and further up to 52% after annealing at 400 °C in a N{sub 2} ambient for 1 h. These improvements are either comparable to or better than the effects of UV-curing. They are attributed to an enhancement of the Si-O-Si network structure. The k-value of the SiCOH films increased slightly after Cs implantation, and increased further after annealing. These increases are attributed to two carbon-loss mechanisms, i.e., the carbon loss due to Si-CH{sub 3} bond breakage from implanted Cs ions, and the carbon loss due to oxidation during the annealing. The time-zero dielectric breakdown strength was improved after the Cs implantation and the annealing, and was better than the UV-cured sample. These results indicate that Cs ion implantation could be a supplement to or a substitution for the currently used UV curing method for processing SiCOH low-k films.

  20. Functional characterization of the ER stress induced X-box-binding protein-1 (Xbp-1 in the porcine system

    Directory of Open Access Journals (Sweden)

    Jin Dong-Il

    2011-05-01

    Full Text Available Abstract Background The unfolded protein response (UPR is an evolutionary conserved adaptive reaction for increasing cell survival under endoplasmic reticulum (ER stress conditions. X-box-binding protein-1 (Xbp1 is a key transcription factor of UPR that activates genes involved in protein folding, secretion, and degradation to restore ER function. The UPR induced by ER stress was extensively studied in diseases linked to protein misfolding and aggregations. However, in the porcine system, genes in the UPR pathway were not investigated. In this study, we isolated and characterized the porcine Xbp1 (pXbp1 gene in ER stress using porcine embryonic fibroblast (PEF cells and porcine organs. ER stress was induced by the treatment of tunicamycin and cell viability was investigated by the MTT assay. For cloning and analyzing the expression pattern of pXbp1, RT-PCR analysis and Western blot were used. Knock-down of pXbp1 was performed by the siRNA-mediated gene silencing. Results We found that the pXbp1 mRNA was the subject of the IRE1α-mediated unconventional splicing by ER stress. Knock-down of pXbp1 enhanced ER stress-mediated cell death in PEF cells. In adult organs, pXbp1 mRNA and protein were expressed and the spliced forms were detected. Conclusions It was first found that the UPR mechanisms and the function of pXbp1 in the porcine system. These results indicate that pXbp1 plays an important role during the ER stress response like other animal systems and open a new opportunity for examining the UPR pathway in the porcine model system.

  1. A new Fe–Mn–Si alloplastic biomaterial as bone grafting material: In vivo study

    Energy Technology Data Exchange (ETDEWEB)

    Fântânariu, Mircea, E-mail: mfantanariu@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, Str. Aleea M. Sadoveanu, no. 8, 700489, Iasi (Romania); Trincă, Lucia Carmen, E-mail: lctrinca@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, Str. Aleea M. Sadoveanu, no. 3, 700490, Iasi (Romania); Solcan, Carmen, E-mail: csolcan@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, Str. Aleea M. Sadoveanu, no. 8, 700489, Iasi (Romania); Trofin, Alina, E-mail: aetrofin@yahoo.com [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Horticulture, Str. Aleea M. Sadoveanu, no. 3, 700490, Iasi (Romania); Strungaru, Ştefan, E-mail: strungaru_stefan@yahoo.com [“Alexandru Ioan Cuza” University, Faculty of Biology, Bulevardul Carol I, Nr.11, 700506, Iasi (Romania); Şindilar, Eusebiu Viorel, E-mail: esindilar@uaiasi.ro [“Ion Ionescu de la Brad” University of Agricultural Sciences and Veterinary Medicine, Faculty of Veterinary Medicine, Str. Aleea M. Sadoveanu, no. 8, 700489, Iasi (Romania); Plăvan, Gabriel, E-mail: gabriel.plavan@uaic.ro [“Alexandru Ioan Cuza” University, Faculty of Biology, Bulevardul Carol I, Nr.11, 700506, Iasi (Romania); and others

    2015-10-15

    Highlights: • A Fe–Mn–Si alloy was obtained as alloplastic graft material for bone implants. • Fe–Mn–Si alloy degradation rate was preliminary evaluate with SEM and EDAX techniques. • Biochemical, histological, RX and CT investigations were done in rats with subcutaneous and tibiae implants. • Fe–Mn–Si alloy assured an ideal compromise between degradation and mechanical integrity during bone regeneration. - Abstract: Designing substrates having suitable mechanical properties and targeted degradation behavior is the key's development of bio-materials for medical application. In orthopedics, graft material may be used to fill bony defects or to promote bone formation in osseous defects created by trauma or surgical intervention. Incorporation of Si may increase the bioactivity of implant locally, both by enhancing interactions at the graft–host interface and by having a potential endocrine like effect on osteoblasts. A Fe–Mn–Si alloy was obtained as alloplastic graft materials for bone implants that need long recovery time period. The surface morphology of the resulted specimens was investigated using scanning electrons microscopy (VegaTescan LMH II, SE detector, 30 kV), X-ray diffractions (X’Pert equipment) or X-ray dispersive energy analyze (Bruker EDS equipment). This study objective was to evaluate in vivo the mechanisms of degradation and the effects of its implantation over the main metabolic organs. Biochemical, histological, plain X radiography and computed tomography investigations showed good compatibility of the subcutaneous implants in the rat organism. The implantation of the Fe–Mn–Si alloy, in critical size bone (tibiae) defect rat model, did not induced adverse biological reactions and provided temporary mechanical support to the affected bone area. The biodegradation products were hydroxides layers which adhered to the substrate surface. Fe–Mn–Si alloy assured the mechanical integrity in rat tibiae defects

  2. Amorphization of SiC under ion and neutron irradiation

    Science.gov (United States)

    Snead, L. L.; Zinkle, S. J.; Hay, J. C.; Osborne, M. C.

    1998-05-01

    This paper presents results on the microstructure and physical properties of SiC amorphized by both ion and neutron irradiation. Specifically, 0.56 MeV Si ions have been implanted in single crystal 6H-SiC from ambient through >200°C and the critical threshold for amorphization was measured as a function of the irradiation temperature. From a high resolution transmission electron microscopy (HRTEM) study of the crystalline to amorphous transition region in these materials, elongated pockets of amorphous material oriented parallel to the free surface are observed. Single crystal 6H-SiC and hot pressed and sintered 6H and 3C SiC were neutron irradiated at approximately 70°C to a dose of ˜2.56 dpa causing complete amorphization. Property changes resulting from the crystal to amorphous transition in SiC include a density decrease of 10.8%, a hardness decrease from 38.7 to 21.0 GPa, and a decrease in elastic modulus from 528 to 292 GPa. Recrystallization of the amorphized, single crystal 6H-SiC appears to occur in two stages. In the temperature range of ˜800-1000°C, crystallites nucleate and slowly grow. In the temperature range of 1125-1150°C spontaneous nucleation and rapid growth of crystallites occur. It is further noted that amorphized 6H (alpha) SiC recrystallizes to highly faulted fcc (beta) SiC.

  3. Separation and implantation of the rare isotope {sup 163}Ho

    Energy Technology Data Exchange (ETDEWEB)

    Kieck, Tom; Chrysalidis, Katerina; Dorrer, Holger; Kormannshaus, Stefan; Schmidt, Sebastian; Schneider, Fabian; Wendt, Klaus [JGU Mainz (Germany); Duellmann, Christoph [JGU Mainz (Germany); GSI Darmstadt (Germany); Gamer, Lisa; Gastaldo, Loredana [Universitaet Heidelberg (Germany); Collaboration: ECHo-Collaboration

    2016-07-01

    The ECHo collaboration aims at measuring the electron neutrino mass by recording the spectrum following electron capture of {sup 163}Ho. To reach a sub-eV sensitivity, a large number of individual microcalorimeters is needed, into which the isotope must be implanted in a well-controlled manner. The necessary amount of {sup 163}Ho is produced by neutron irradiation of enriched {sup 162}Er in the ILL high flux reactor. This introduces significant contaminations of other radioisotopes, which have to be quantitatively removed both, by chemical and mass spectrometric separation. The application of resonance ionization at the RISIKO mass separator guarantees the required isotope selectivity for purification and suitable energy for ion implantation. The efficiency and stability of the laser ion source was improved by Finite-Element Analysis of the thermal processes. For optimum implantation into the detector pixels (170 x 170 μm{sup 2}) with minimum losses a small ion beam spot at the implantation site is needed. For this purpose, post focusing ion optics were installed. Simulations were performed in order to optimize the homogeneous distribution of the implanted ions. The necessity to alternate implantation phases with deposition of a thin metallic layer for {sup 163}Ho activities larger than 10 Bq is being discussed.

  4. Failures in implants

    Directory of Open Access Journals (Sweden)

    E Prashanti

    2011-01-01

    Full Text Available The burning problem that all the implantologists are confronted today is the complications and failures occurring with the treatment of osseointegrated implants. To further optimize the treatment outcome, etiologies and factors associated with implant failures should be elucidated. Conceivably such knowledge is needed for developing adequate treatment and prevention strategies. Hence, this paper is intended to provide an insight regarding various aspects of failures that affect dental implants.

  5. Er computerspil andet end spild af tid?

    DEFF Research Database (Denmark)

    Andersen, Christian Ulrik

    2006-01-01

    Som andre fiktionsmedier gennem tiden kan også computerspillet reflektere og kommentere den virkelighed, og ikke mindst medie-virkelighed, det selv er en del af. Dette belyses gennem verdens første computerspil, Spacewar fra 1962. Udgivelsesdato: Februar...

  6. Protesen er også mig

    DEFF Research Database (Denmark)

    Østergaard, Elisabeth Bomholt

    den enkelte en oplevelse af at føle sig set, som den person vedkommende er. Den sundhedsprofessionelles kropssprog er vigtigt, og det er fx særlig vigtigt, at den sundhedsprofessionelle helt konkret ’sætter sig ned’. Det rituelle perspektiv er anvendeligt i forbindelse med kriser, sygdom og handicap...... og kroppen som subjekt. Konklusion: Alle informanterne følte sig hele. De følte sig hele som personer, hvilket ikke afhang af, om de havde protesen på eller ej. Og de følte, at de var blevet sig selv igen – i en ny tilstand. Protesen blev for de flestes vedkommende inkorporeret, så den føltes som en...... del af dem som person og som en del af kroppen, der forlængede deres følelsesradius. De fleste af informanterne oplevede, at de nu kunne glemme kroppen og have fokus andre steder, efter at kroppen i en periode havde gjort krav på fokus. De fleste af informanterne følte, at de igen var blevet en del af...

  7. Magi er forbudt i Det Gamle Testamente

    DEFF Research Database (Denmark)

    Jensen, Hans Jørgen Lundager

    2012-01-01

    Populær redegørelse for holdning til magi og religion if. klassisk religionsvidenskab og for holdninger til magi i GT. På den ene side forbydes magi og trolddom skarpt. På den anden side er der fortællinger og ritualer, vi vil klassificere som magiske, og religion generelt har en uudrydelig 'magi...

  8. Hej, jeg er i bussen nu

    DEFF Research Database (Denmark)

    2010-01-01

    Artiklen tager udgangspunkt i, hvad passagererne taler om i bussen via deres mobiltelefon og sammenholder det med kommunikationssituationen. Derudover er der foretaget interview med de øvrige passagerer for at finde ud af, om de føler sig generet af mobilbrug i bussen. Artiklen baserer sig sålede...

  9. Er iPad digital udeskole?

    DEFF Research Database (Denmark)

    Schilhab, Theresa

    2014-01-01

    Hvor ’konkret’ skal en oplevelse være, for at intuitionen om, at det selvoplevede styrker læringen, holder? Er brug af tablets (e.g. iPads) et ligebyrdigt alternativ til den konkrete oplevelse?...

  10. Developing ER Stress Inhibitors for Treating ALS

    Science.gov (United States)

    2015-11-01

    in response to thapsigargin, an inhibitor of the sarco/endoplasmic reticulum Ca2+ ATPase ( SERCA ) channels which initiates ER stress by preventing...O’Regan, J. P., Deng, H. X., and et al. (1993) Mutations in Cu/Zn superoxide dismutase gene are associated with familial amyotrophic lateral

  11. Socialrådgiveruddannelsen er igen truet

    DEFF Research Database (Denmark)

    Arnfjord, Steven; Abelsen, Sara; Poppel, Marie Katrine

    2017-01-01

    Kronikken diskuterer betydningen af at fastholde socialrådgiveruddannelsen i Grønland som et fag ved universitetet i Nuuk, således at der sikrer et akademisk refleksions-niveau - hvilket er betydningsfuldt i en tid, hvor en række sociale problemer i Grønland stadig findes især blandt de grupper, ...

  12. Hvad nu hvis sommerfuglen er ekshibitionist?

    DEFF Research Database (Denmark)

    Rösing, Lilian Munk

    2008-01-01

    Groft sagt vil denne artikel, ved at aflæse hvad hhv. Inger Christensen, Sigmund Freud og Jacques Lacan har at sige om sommerfugle, argumentere for at der er et afgørende skel mellem naturvidenskab og litteraturvidenskab; mellem naturen, dyret, sommerfuglen på den ene side og bevidstheden...

  13. Hvad er PET og fMRI?

    DEFF Research Database (Denmark)

    B. Paulson, Olaf; Balslev, Daniela; Gerlach, Christian

    2007-01-01

    Hvilken rolle spiller følelserne for vores tankeliv, og hvorfor har vi overhovedet følelser? I kraft af avancerede hjerneskanningsteknikker er den moderne hjernevidenskab blevet i stand til at besvare disse spørgsmål. Gennem artiklerne i denne antologi, skrevet af ledende danske forskere, bliver ...

  14. Creating Smart-er Cities: An Overview

    Science.gov (United States)

    Allwinkle, Sam; Cruickshank, Peter

    2011-01-01

    The following offers an overview of what it means for cities to be "smart." It draws the supporting definitions and critical insights into smart cities from a series of papers presented at the 2009 Trans-national Conference on Creating Smart(er) Cities. What the papers all have in common is their desire to overcome the all too often…

  15. Hvad er hjemkundskabslæreren?

    DEFF Research Database (Denmark)

    Benn, Jette

    2009-01-01

        En appetizer: De praktisk-musiske fag på dagsordenen Temaet for denne artikel er hjemkundskabsfaget, -professionen og dens praktisering belyst gennem et interviewstudie fra 2008 af lærerstuderende og deres lærere. Dette studie relateres til forfatterens tidligere studie af fag og profession i...

  16. Svinehunden er løs

    DEFF Research Database (Denmark)

    Post, Bettina

    2007-01-01

    Det er blevet tilladt at kalde socialt udsatte for "tabere" samtidig med, at troen på virkningen af de økonomiske incitamenter i kontanthjælpssystemet hærger ufortrødent hen over al den dokumentation, der viser, at de ikke virker....

  17. A review: Cochlear implants

    OpenAIRE

    Batman, Ç.; Üneri, C.; Şehitoijlu, M.A.

    1991-01-01

    Electrical stimulation of the auditory system in deaf individuals has been first explained in 1935 by Andreev et al. and in 1940 by Jones et al, resulting in sensation of hearing (1,2). These attempts are facilitated by Djourno et al who first implanted electrical devices in two subjects in 1957 (3). But this type of stimulation has been a controversy until 1974, when cochlear implant was successfully implanted by W.F. House. Since that time over 5000 individuals have been implanted with a va...

  18. Ion implantation technology

    CERN Document Server

    Downey, DF; Jones, KS; Ryding, G

    1993-01-01

    Ion implantation technology has made a major contribution to the dramatic advances in integrated circuit technology since the early 1970's. The ever-present need for accurate models in ion implanted species will become absolutely vital in the future due to shrinking feature sizes. Successful wide application of ion implantation, as well as exploitation of newly identified opportunities, will require the development of comprehensive implant models. The 141 papers (including 24 invited papers) in this volume address the most recent developments in this field. New structures and possible approach

  19. Gallium-Doped Poly-Si:Ga/SiO2 Passivated Emitters to n-Cz Wafers With iV oc >730 mV

    Energy Technology Data Exchange (ETDEWEB)

    Young, David L.; Lee, Benjamin G.; Fogel, Derek; Nemeth, William; LaSalvia, Vincenzo; Theingi, San; Page, Matthew; Young, Matthew; Perkins, Craig; Stradins, Paul

    2017-11-01

    We form gallium-doped poly-Si:Ga/SiO2 passivated contacts on n-type Czochralski (n-Cz) wafers using ion implantation of Ga and Ga-containing spin-on dopants. After annealing and passivation with Al2O3 , the contacts exhibit iVoc values of >730 mV with corresponding Joe values of <5 fA/cm2 . These are among the best-reported values for p-type poly-Si/SiO2 contacts. Secondary ion mass spectroscopic depth profile data show that, in contrast to B, Ga does not pileup at the SiO2 interface in agreement with its known high diffusivity in SiO2. This lack of Ga pileup may imply fewer dopant-related defects in the SiO2, compared with B dopants, and account for the excellent passivation.

  20. Neural Implants, Packaging for Biocompatible Implants, and Improving Fabricated Capacitors

    Science.gov (United States)

    Agger, Elizabeth Rose

    We have completed the circuit design and packaging procedure for an NIH-funded neural implant, called a MOTE (Microscale Optoelectronically Transduced Electrode). Neural recording implants for mice have greatly advanced neuroscience, but they are often damaging and limited in their recording location. This project will result in free-floating implants that cause less damage, provide rapid electronic recording, and increase range of recording across the cortex. A low-power silicon IC containing amplification and digitization sub-circuits is powered by a dual-function gallium arsenide photovoltaic and LED. Through thin film deposition, photolithography, and chemical and physical etching, the Molnar Group and the McEuen Group (Applied and Engineering Physics department) will package the IC and LED into a biocompatible implant approximately 100microm3. The IC and LED are complete and we have begun refining this packaging procedure in the Cornell NanoScale Science & Technology Facility. ICs with 3D time-resolved imaging capabilities can image microorganisms and other biological samples given proper packaging. A portable, flat, easily manufactured package would enable scientists to place biological samples on slides directly above the Molnar group's imaging chip. We have developed a packaging procedure using laser cutting, photolithography, epoxies, and metal deposition. Using a flip-chip method, we verified the process by aligning and adhering a sample chip to a holder wafer. In the CNF, we have worked on a long-term metal-insulator-metal (MIM) capacitor characterization project. Former Fellow and continuing CNF user Kwame Amponsah developed the original procedure for the capacitor fabrication, and another former fellow, Jonilyn Longenecker, revised the procedure and began the arduous process of characterization. MIM caps are useful to clean room users as testing devices to verify electronic characteristics of their active circuitry. This project's objective is to

  1. Nanoporous Ge thin film production combining Ge sputtering and dopant implantation

    Directory of Open Access Journals (Sweden)

    Jacques Perrin Toinin

    2015-01-01

    Full Text Available In this work a novel process allowing for the production of nanoporous Ge thin films is presented. This process uses the combination of two techniques: Ge sputtering on SiO2 and dopant ion implantation. The process entails four successive steps: (i Ge sputtering on SiO2, (ii implantation preannealing, (iii high-dose dopant implantation, and (iv implantation postannealing. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of the Ge film at different process steps under different postannealing conditions. For the same postannealing conditions, the Ge film topology was shown to be similar for different implantation doses and different dopants. However, the film topology can be controlled by adjusting the postannealing conditions.

  2. Comprehensive study on effect of sintering temperature on the physical, structural and optical properties of Er3+ doped ZnO-GSLS glasses

    Science.gov (United States)

    Rashid, Siti Syuhaida Abdul; Aziz, Sidek Hj. Ab; Matori, Khamirul Amin; Zaid, Mohd Hafiz Mohd; Mohamed, Nurzilla

    The Er3+ doped zinc soda lime silica (ZnO-GSLS) glass system was prepared by the conventional melt-quenching technique using waste green soda lime silica (GSLS) glass, zinc oxide (ZnO) and erbium oxide (Er2O3) powder as starting materials. Er3+ doped willemite based glass-ceramics (Zn2SiO4:Er3+) were derived from this precursor glass by a controlled sintering process. The effect of sintering temperature on the density and linear shrinkage of the sample was investigated. XRD analysis revealed the presence of thermodynamically stable zinc orthosilicate (α-Zn2SiO4) phase at sintering temperatures above 700 °C. FESEM image shows the presence of densely packed grains as the sintering temperature increase. FTIR spectroscopy was used to observe the structural of SiO4 and ZnO4 groups in the formation of willemite phase evolution. The UV-Vis absorption spectra reveals four peaks centered at excitation of electron from ground state 4I15/2 to 4G11/2 (∼363 nm),4F7/2 (∼488 nm), 2H11/2 (∼523 nm), and 4F9/2 (∼652 nm). PL spectroscopy measurements were performed at room temperature using 385 nm excitation wavelengths. Enhancement of the Er3+ luminescence was observed with the progression of sintering temperature.

  3. Gene expression alterations associated with outcome in aromatase inhibitor-treated ER+ early-stage breast cancer patients

    DEFF Research Database (Denmark)

    Thomsen, Karina G; Lyng, Maria B; Elias, Daniel

    2015-01-01

    Aromatase inhibitors (AI), either alone or together with chemotherapy, have become the standard adjuvant treatment for postmenopausal, estrogen receptor-positive (ER+) breast cancer. Although AIs improve overall survival, resistance is still a major clinical problem, thus additional biomarkers...... predictive of outcome of ER+ breast cancer patients treated with AIs are needed. Global gene expression analysis was performed on ER+ primary breast cancers from patients treated with adjuvant AI monotherapy; half experienced recurrence (median follow-up 6.7 years). Gene expression alterations were validated...... by qRT-PCR, and functional studies evaluating the effect of siRNA-mediated gene knockdown on cell growth were performed. Twenty-six genes, including TFF3, DACH1, RGS5, and GHR, were shown to exhibit altered expression in tumors from patients with recurrence versus non-recurrent (fold change ≥1.5, p

  4. Tunnel oxide passivated contacts formed by ion implantation for applications in silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Reichel, Christian, E-mail: christian.reichel@ise.fraunhofer.de [Fraunhofer Institute for Solar Energy Systems (ISE), Heidenhofstrasse 2, 79110 Freiburg (Germany); National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway, Golden, Colorado 80401 (United States); Feldmann, Frank; Müller, Ralph; Hermle, Martin; Glunz, Stefan W. [Fraunhofer Institute for Solar Energy Systems (ISE), Heidenhofstrasse 2, 79110 Freiburg (Germany); Reedy, Robert C.; Lee, Benjamin G.; Young, David L.; Stradins, Paul [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway, Golden, Colorado 80401 (United States)

    2015-11-28

    Passivated contacts (poly-Si/SiO{sub x}/c-Si) doped by shallow ion implantation are an appealing technology for high efficiency silicon solar cells, especially for interdigitated back contact (IBC) solar cells where a masked ion implantation facilitates their fabrication. This paper presents a study on tunnel oxide passivated contacts formed by low-energy ion implantation into amorphous silicon (a-Si) layers and examines the influence of the ion species (P, B, or BF{sub 2}), the ion implantation dose (5 × 10{sup 14 }cm{sup −2} to 1 × 10{sup 16 }cm{sup −2}), and the subsequent high-temperature anneal (800 °C or 900 °C) on the passivation quality and junction characteristics using double-sided contacted silicon solar cells. Excellent passivation quality is achieved for n-type passivated contacts by P implantations into either intrinsic (undoped) or in-situ B-doped a-Si layers with implied open-circuit voltages (iV{sub oc}) of 725 and 720 mV, respectively. For p-type passivated contacts, BF{sub 2} implantations into intrinsic a-Si yield well passivated contacts and allow for iV{sub oc} of 690 mV, whereas implanted B gives poor passivation with iV{sub oc} of only 640 mV. While solar cells featuring in-situ B-doped selective hole contacts and selective electron contacts with P implanted into intrinsic a-Si layers achieved V{sub oc} of 690 mV and fill factor (FF) of 79.1%, selective hole contacts realized by BF{sub 2} implantation into intrinsic a-Si suffer from drastically reduced FF which is caused by a non-Ohmic Schottky contact. Finally, implanting P into in-situ B-doped a-Si layers for the purpose of overcompensation (counterdoping) allowed for solar cells with V{sub oc} of 680 mV and FF of 80.4%, providing a simplified and promising fabrication process for IBC solar cells featuring passivated contacts.

  5. Optical switching and photoluminescence in erbium-implanted vanadium dioxide thin films

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Herianto, E-mail: mail@heriantolim.com; Stavrias, Nikolas; Johnson, Brett C.; McCallum, Jeffrey C. [School of Physics, University of Melbourne, Parkville, Victoria 3010 (Australia); Marvel, Robert E.; Haglund, Richard F. [Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37240 (United States)

    2014-03-07

    Vanadium dioxide (VO{sub 2}) is under intensive consideration for optical switching due to its reversible phase transition, which features a drastic and rapid shift in infrared reflectivity. Classified as an insulator–to–metal transition, the phase transition in VO{sub 2} can be induced thermally, electrically, and optically. When induced optically, the transition can occur on sub-picosecond time scales. It is interesting to dope VO{sub 2} with erbium ions (Er{sup 3+}) and observe their combined properties. The first excited-state luminescence of Er{sup 3+} lies within the wavelength window of minimal transmission-loss in silicon and has been widely utilized for signal amplification and generation in silicon photonics. The incorporation of Er{sup 3+} into VO{sub 2} could therefore result in a novel photonic material capable of simultaneous optical switching and amplification. In this work, we investigate the optical switching and photoluminescence in Er-implanted VO{sub 2} thin films. Thermally driven optical switching is demonstrated in the Er-implanted VO{sub 2} by infrared reflectometry. Photoluminescence is observed in the thin films annealed at ∼800 °C or above. In addition, Raman spectroscopy and a statistical analysis of switching hysteresis are carried out to assess the effects of the ion implantation on the VO{sub 2} thin films. We conclude that Er-implanted VO{sub 2} can function as an optical switch and amplifier, but with reduced switching quality compared to pure VO{sub 2}.

  6. Energy transfer from the host to Er{sup 3+} dopants in semiconductor SnO{sub 2} nanocrystals segregated in sol-gel silica glasses

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, Javier del [Universidad de La Laguna, Departamento Fisica Basica (Spain)], E-mail: fjvargas@ull.es; Rodriguez, V. D. [Universidad de La Laguna, Departamento Fisica Fundamental y Experimental, Electronica y Sistemas (Spain)], E-mail: vrguez@ull.es; Yanes, A. C. [Universidad de La Laguna, Departamento Fisica Basica (Spain); Mendez-Ramos, J. [Universidad de La Laguna, Departamento Fisica Fundamental y Experimental, Electronica y Sistemas (Spain)

    2008-03-15

    Undoped and Er{sup 3+}-doped glass-ceramics of composition (100-x)SiO{sub 2}-xSnO{sub 2}, with x = 5 or 10 and with 0.4 or 0.8 mol% of Er{sup 3+} ions, were synthesised by thermal treatment of precursor sol-gel glasses. Structural studies were developed by X-Ray Diffraction. Wide band gap SnO{sub 2} semiconductor quantum-dots embedded in the insulator SiO{sub 2} glass are obtained. The mean radius of the SnO{sub 2} nanocrystals, ranging from 2 to 3.2 nm, is comparable to the exciton Bohr radius. The luminescence properties have been analysed as a function of sample composition and thermal treatment. The results show that Er{sup 3+} ions are partially partitioned into the nanocrystalline phase. An efficient UV excitation of the Er{sup 3+} ions by energy transfer from the SnO{sub 2} nanocrystal host is observed. The Er{sup 3+} ions located in the SnO{sub 2} nanocrystals are selectively excited by this energy transfer mechanism. On the other hand, emission from the Er{sup 3+} ions remaining in the silica glassy phase is obtained by direct excitation of these ions.

  7. The effect of different cleaning methods on the surface and temperature of failed titanium implants: an in vitro study.

    Science.gov (United States)

    Hakki, Sema S; Tatar, Gulsah; Dundar, Niyazi; Demiralp, Burak

    2017-04-01

    The aims of this in vitro study are to compare the efficacy of different cleaning methods in removing debris of failed implants and to detect thermal changes of the implants treated by various scaling instruments. Twenty-seven failed implants and two unused implants as control were included to this study-group 1: plastic curette (P), group 2: titanium curette (T), group 3: carbon curette (C), group 4: titanium brush (TB), group 5: Er:YAG laser (laser 1 (L1) 100 mJ/pulse at 10 Hz), group 6: Er:YAG laser (laser 2 (L2) 150 mJ/pulse at 10 Hz), group 7: Er:YAG laser (laser 3 (L3) 200 mJ/pulse at 10 Hz), group 8: ultrasonic scaler appropriate for titanium (US), group 9: air abrasive method (AA) + citric acid, and group 10: implantoplasty (I). The changes on the treated/untreated titanium surfaces and remnant debris were observed by scanning electron microscopy (SEM). Temperature of the implants before and after treatment was detected using a thermocouple. The use of air abrasive and citric acid combination and Er:YAG laser groups was found as the best methods for the decontamination of titanium surfaces of failed implant. When the hand instruments were compared, titanium curette was found better than both the plastic and the carbon curettes which leave plastics and carbon remnants on the titanium surface. The temperature was higher after hand instrumentation when compared to other experimental groups (p < 0.05). Within the limitations of the present in vitro model, it can be concluded that the best method for decontamination of the implant surface is the use of air abrasives and Er:YAG laser.

  8. Materials design considerations involved in the fabrication of implantable bionics by metallization of ceramic substrates.

    Science.gov (United States)

    Patel, Sunil; Guenther, Thomas; Dodds, Christopher W D; Kolke, Sergej; Privat, Karen L; Matteucci, Paul B; Suaning, Gregg J

    2013-01-01

    The Pt metallization of co-fired Al2O3/SiO2 substrates containing Pt feedthroughs was shown to be a suitable means to construct implantable bionics. The use of forge welding to join an electrode to such a metallized feedthrough was demonstrated and subsequently evaluated through the use of metallography and electron microscopy. Metallurgical phenomena involved in forge welding relevant to the fabrication of all types of biomedical implants are discussed within this paper. The affect of thermal profiles used in brazing or welding to build implantable devices from metal components is analysed and the case for considered selection of alloys in implant design is put forward.

  9. Contribution of geometric design parameters to knee implant performance: Conflicting impact of conformity on kinematics and contact mechanics.

    Science.gov (United States)

    Ardestani, Marzieh M; Moazen, Mehran; Jin, Zhongmin

    2015-06-01

    Articular geometry of knee implant has a competing impact on kinematics and contact mechanics of total knee arthroplasty (TKA) such that geometry with lower contact pressure will impose more constraints on knee kinematics. The geometric parameters that may cause this competing effect have not been well understood. This study aimed to quantify the underlying relationships between implant geometry as input and its performance metrics as output. Parametric dimensions of a fixed-bearing cruciate retaining implant were randomized to generate a number of perturbed implant geometries. Performance metrics (i.e., maximum contact pressure, anterior-posterior range of motion [A-P ROM] and internal-external range of motion [I-E ROM]) of each randomized design were calculated using finite element analysis. The relative contributions of individual geometric variables to the performance metrics were then determined in terms of sensitivity indices (SI). The femoral and tibial distal or posterior radii and femoral frontal radius are the key parameters. In the sagittal plane, distal curvature of the femoral and tibial influenced both contact pressure, i.e., SI=0.57; SI=0.65, and A-P ROM, i.e., SI=0.58; SI=0.6, respectively. However, posterior curvature of the femoral and tibial implants had a smaller impact on the contact pressure, i.e., SI=0.31; SI=0.23 and a higher impact on the I-E ROM, i.e., SI=0.72; SI=0.58. It is noteworthy that in the frontal plane, frontal radius of the femoral implant impacted both contact pressure (SI=0.38) and I-E ROM (SI=0.35). Findings of this study highlighted how changes in the conformity of the femoral and tibial can impact the performance metrics. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. MGS MARS/MOONS MAG/ER MAPPING ER ANGULAR FLUX V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set consists of calibrated, time-ordered, angle-resolved electron flux data from the Electron Reflectometer (ER) instrument on the Mars Global Surveyor...

  11. Effects of MgO and SiO2 on Plasma-Sprayed Hydroxyapatite Coating: An in Vivo Study in Rat Distal Femoral Defects.

    Science.gov (United States)

    Ke, Dongxu; Robertson, Samuel F; Dernell, William S; Bandyopadhyay, Amit; Bose, Susmita

    2017-08-09

    Plasma-sprayed hydroxyapatite (HA)-coated titanium implants have been widely used in orthopedic applications due to their inheritance of an excellent mechanical property from titanium and great osteoconductivity from HA. However, the lack of osteoinductivity limits their further applications. In this study, 1 wt % MgO and 0.5 wt % SiO2 were mixed with HA for making plasma-sprayed coatings on titanium implants. Plasma-sprayed HA- and MgO/SiO2-HA-coated titanium implants showed adhesive bond strengths of 25.73 ± 1.92 and 23.44 ± 2.89 MPa, respectively. The presence of MgO and SiO2 significantly increased the osteogenesis, osseointegration, and bone mineralization of HA-coated titanium implants by the evaluation of their histomorphology after 6, 10, and 14 weeks of implantation in rat distal femoral defects. Implant pushout tests also showed a shear modulus of 149.83 ± 3.69 MPa for MgO/SiO2-HA-coated implants after 14 weeks of implantation, compared to 52.68 ± 10.41 MPa for uncoated implants and 83.92 ± 3.68 MPa for pure HA-coated implants; These are differences in the shear modulus of 96% and 56.4%, respectively. This study assesses for the first time the quality of the bone-implant interface of induction plasma-sprayed MgO and SiO2 binary-doped HA coatings on load-bearing implants compared to bare titanium and pure HA coatings in a quantitative manner. Relating the osseointegration and interface shear modulus to the quality of implant fixation is critical to the advancement and implementation of HA-coated orthopedic implants.

  12. ER-mitochondria contacts: Actin dynamics at the ER control mitochondrial fission via calcium release.

    Science.gov (United States)

    Steffen, Janos; Koehler, Carla M

    2018-01-02

    The formin-like protein INF2 is an important player in the polymerization of actin filaments. In this issue, Chakrabarti et al. (2018. J. Cell Biol. https://doi.org/10.1083/jcb.201709111) demonstrate that INF2 mediates actin polymerization at the endoplasmic reticulum (ER), resulting in increased ER-mitochondria contacts, calcium uptake by mitochondria, and mitochondrial division. © 2018 Steffen and Koehler.

  13. Au-Ag nanoalloy molecule-like clusters for enhanced quantum efficiency emission of Er³⁺ ions in silica.

    Science.gov (United States)

    Cesca, Tiziana; Kalinic, Boris; Michieli, Niccolò; Maurizio, Chiara; Trapananti, Angela; Scian, Carlo; Battaglin, Giancarlo; Mazzoldi, Paolo; Mattei, Giovanni

    2015-11-14

    The occurrence of a very efficient non-resonant energy transfer process forming ultrasmall Au-Ag nanoalloy clusters and Er(3+) ions is investigated in silica. The enhancement of the room temperature Er(3+) emission efficiency by an order of magnitude is achieved by coupling rare-earth ions to molecule-like (Au(x)Ag(1-x))N alloy nanoclusters with N = 10-15 atoms and x = 0.6 obtained by optimized sequential ion implantation on Er-implanted silica. For comparison, AuN nanoclusters obtained by the same approach and with the same size and numerical density showed an enhancement by only a factor of 2 with respect to pure Er emission, demonstrating the beneficial effect of using nanoalloyed clusters. The temperature evolution of the energy transfer process is investigated by photoluminescence and exhibits a maximum efficiency at about 600 °C, where the clusters reach the optimal size and the silica matrix completely recovers the implantation damage. The nanoalloy cluster composition and size have been studied by EXAFS analysis, which indicated a stronger Ag-O interaction with respect to the Au-O one and a preferential location of the Ag atoms at the nanoalloy cluster surface.

  14. Doping of silicon carbide by ion implantation; Dopage du carbure de silicium par implantation ionique

    Energy Technology Data Exchange (ETDEWEB)

    Gimbert, J

    1999-03-04

    It appeared that in some fields, as the hostile environments (high temperature or irradiation), the silicon compounds showed limitations resulting from the electrical and mechanical properties. Doping of 4H and 6H silicon carbide by ion implantation is studied from a physicochemical and electrical point of view. It is necessary to obtain n-type and p-type material to realize high power and/or high frequency devices, such as MESFETs and Schottky diodes. First, physical and electrical properties of silicon carbide are presented and the interest of developing a process technology on this material is emphasised. Then, physical characteristics of ion implantation and particularly classical dopant implantation, such as nitrogen, for n-type doping, and aluminium and boron, for p-type doping are described. Results with these dopants are presented and analysed. Optimal conditions are extracted from these experiences so as to obtain a good crystal quality and a surface state allowing device fabrication. Electrical conduction is then described in the 4H and 6H-SiC polytypes. Freezing of free carriers and scattering processes are described. Electrical measurements are carried out using Hall effect on Van der Panw test patterns, and 4 point probe method are used to draw the type of the material, free carrier concentrations, resistivity and mobility of the implanted doped layers. These results are commented and compared to the theoretical analysis. The influence of the technological process on electrical conduction is studied in view of fabricating implanted silicon carbide devices. (author)

  15. Annealing behaviour of MeV erbium implanted lithium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Gortmaker, P.; McCallum, J.C. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Lithium niobate (LiNbO{sub 3}) is a crystalline ceramic commonly used in the fabrication of optoelectronic devices. Recently, rare earth doping of LiNbO{sub 3} has become a topic of particular interest. The electronic configuration of rare earth elements such as Erbium (Er) and Neodymium (Nd) allows them to lase in nearly any host matrix making fabrication of a whole range of new optoelectronic devices possible. At present, the doping technique, for LiNbO{sub 3} are centred upon diffusion technology, but the diffusion profiles for the rare earths are not generally well-matched to the optical modes of the device. The aim of this research is to develop MeV implantation and annealing conditions of rare earth doped LiNbO{sub 3} that would be compatible with optoelectronic device fabrication. To determine the characteristics of the rare earth elements in the LiNbO{sub 3} host material over the depth range of interest in optoelectronic device applications, high energy Rutherford backscattering spectrometry and ion channeling (RBS-C) must be used. Presented here are the Er depth profile and lattice damage results obtained from 5 MeV RBS-C measurements on samples of LiNbO{sub 3} implanted with various doses of MeV Erbium and subsequently thermally annealed at a temperature of 1000 deg C. It was found that there is a peak implant concentration (2 x 10{sup 16} Er/cm{sup 2}) for which erbium no longer goes substitutional in the lattice, and the implantation damage is not fully removed by annealing. 8 refs., 3 figs.

  16. I. Heteroepitaxy on Silicon. I. Ion Implantation in Silicon and Heterostructures

    Science.gov (United States)

    Bai, Gang

    The themes of this thesis, heteroepitaxy and ion implantation, are two areas that have been very actively researched in the last two decades. Heterostructures made of III-V compound semiconductors by MBE and OMVPE have been used extensively in the fabrication of optoelectronics devices such as high-speed transistors and semiconductor lasers. Heterostructures on Si, which is the focus of part I of this thesis, have the advantage of compatibility with Si-based VLSI and promise to have impact on the microelectronics industry. Studies on the structural, elastic, thermal, and electrical properties of heteroepitaxial CoSi_2, ReSi _2, and GeSi films grown on Si constitute the backbone of this thesis. Some new characteristics of heterostructures were discovered as a result of this investigation. Among them are the observation and modeling of misorientation effects on an epitaxial film grown on a vicinal substrate; the misorientation induced by interfacial misfit dislocation arrays; the experimental measurements and phenomenological analysis of thermal strain, dislocation generation, and strain relaxation; and illustrative measurements of elastic, thermal, and structural properties of epitaxial films. Ion implantation is an important process in the fabrication of integrated circuits. The second part of this thesis deals with the production and annealing of damage produced by ion implantation in semiconductors. The defect production, stability, microstructure, and the induced strain in implanted bulk Si crystals were quantitatively investigated as a function of ion species, dose, and implantation temperature. Many new features, such as the rapid rise of damage near the amorphization threshold, the correlation between the strain and defect concentration, and the scaling behavior of the damage with ion species and implantation temperature, are revealed. The last chapter concerns the effects of ion implantation in CoSi_2, ReSi_2 , and GeSi/Si heterostructures, which is a

  17. TCSP ER-2 MICROWAVE TEMPERATURE PROFILER (MTP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The TCSP ER-2 Microwave Temperature Profiler (MTP) dataset was collected by the ER-2 Microwave Temperature Profiler (MTP), which is a passive microwave radiometer...

  18. Hvornår er agil projektledelse rigtig?

    DEFF Research Database (Denmark)

    Pries-Heje, Jan

    2011-01-01

    Styrken ved agil projektledelse er hurtigheden og muligheden for at absorbere ændringer hurtigt gennem hele projektets løbetid, men der er naturligvis også nogle svagheder. Nogle af dem nævner jeg i artiklen, men derudover egner agil-formen sig ikke specielt godt til komplicerede projekter, hvor...... liv eller mange penge er på spil. Agil-formen er heller ikke velegnet til umotiverede medarbejdere, fordi de ikke har noget at bidrage med. For en projektleder synes jeg, at det er væsentligt at have et dybdegående kendskab til positive og negative sider ved både agil og plandreven projektledelse....... Verden er kompleks, og vores projekter derfor er tilsvarende komplekse. Som projektleder bør man således kunne analysere sig frem til den rigtige form for projektledelse, uanset om det er agil projektledelse eller ej....

  19. CAMEX-4 ER-2 LIGHTNING INSTRUMENT PACKAGE (LIP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The CAMEX-4 ER-2 Lightning Instrument Package (LIP) dataset was collected by the ER-2 LIP, which allows the vector components of the electric field (i.e, Ex, Ey, Ez...

  20. ER Consolidated Qtrly Rpt_April-June 2016_October 2016

    Energy Technology Data Exchange (ETDEWEB)

    Cochran, John R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    This Environmental Restoration Operations (ER) Consolidated Quarterly Report (ER Quarterly Report) provides the status of ongoing corrective action activities being implemented by Sandia National Laboratories, New Mexico (SNL/NM) for the April, May, and June 2016 quarterly reporting period.

  1. GPM Ground Validation Navigation Data ER-2 OLYMPEX V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPM Ground Validation NASA ER-2 Navigation Data OLYMPEX dataset supplies navigation data collected by the NASA ER-2 aircraft for flights that occurred during...

  2. Senior Sport er læring i virkeligheden

    DEFF Research Database (Denmark)

    Meyer, Erna Rosenlund

    2014-01-01

    Samarbejde mellem fysioterapeutudddannelsen på UCN og Aalborg senior Sport er givende for alle parter, inklusiv studerende.......Samarbejde mellem fysioterapeutudddannelsen på UCN og Aalborg senior Sport er givende for alle parter, inklusiv studerende....

  3. PODAAC-ERS2X-IMWF0

    Data.gov (United States)

    National Aeronautics and Space Administration — The European Remote Sensing Satellite generation 2 (ERS-2) Level 3 Mean Wind Fields dataset is derived from the ERS-2 scatterometer data and is produced and...

  4. In vivo ultrasonic detection of polyurea crosslinked silica aerogel implants.

    Directory of Open Access Journals (Sweden)

    Firouzeh Sabri

    Full Text Available BACKGROUND: Polyurea crosslinked silica aerogels are highly porous, lightweight, and mechanically strong materials with great potential for in vivo applications. Recent in vivo and in vitro studies have demonstrated the biocompatibility of this type of aerogel. The highly porous nature of aerogels allows for exceptional thermal, electric, and acoustic insulating capabilities that can be taken advantage of for non-invasive external imaging techniques. Sound-based detection of implants is a low cost, non-invasive, portable, and rapid technique that is routinely used and readily available in major clinics and hospitals. METHODOLOGY: In this study the first in vivo ultrasound response of polyurea crosslinked silica aerogel implants was investigated by means of a GE Medical Systems LogiQe diagnostic ultrasound machine with a linear array probe. Aerogel samples were inserted subcutaneously and sub-muscularly in a fresh animal model and b cadaveric human model for analysis. For comparison, samples of polydimethylsiloxane (PDMS were also imaged under similar conditions as the aerogel samples. CONCLUSION/SIGNIFICANCE: Polyurea crosslinked silica aerogel (X-Si aerogel implants were easily identified when inserted in either of the regions in both fresh animal model and cadaveric model. The implant dimensions inferred from the images matched the actual size of the implants and no apparent damage was sustained by the X-Si aerogel implants as a result of the ultrasonic imaging process. The aerogel implants demonstrated hyperechoic behavior and significant posterior shadowing. Results obtained were compared with images acquired from the PDMS implants inserted at the same location.

  5. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne

    2012-01-01

    We evaluated the association between radiation therapy and severe capsular contracture or reoperation after 717 delayed breast implant reconstruction procedures (288 1- and 429 2-stage procedures) identified in the prospective database of the Danish Registry for Plastic Surgery of the Breast during...... reconstruction approaches other than implants should be seriously considered among women who have received radiation therapy....

  6. HA-Coated Implant

    DEFF Research Database (Denmark)

    Daugaard, Henrik; Søballe, Kjeld; Bechtold, Joan E

    2014-01-01

    The goal of osseointegration of orthopedic and dental implants is the rapid achievement of a mechanically stable and long lasting fixation between living bone and the implant surface. In total joint replacements of cementless designs, coatings of calcium phosphates were introduced as a means...

  7. Implantable CMOS Biomedical Devices

    Directory of Open Access Journals (Sweden)

    Toshihiko Noda

    2009-11-01

    Full Text Available The results of recent research on our implantable CMOS biomedical devices are reviewed. Topics include retinal prosthesis devices and deep-brain implantation devices for small animals. Fundamental device structures and characteristics as well as in vivo experiments are presented.

  8. Penta-EF-Hand Protein Peflin Is a Negative Regulator of ER-To-Golgi Transport.

    Directory of Open Access Journals (Sweden)

    Mariah Rayl

    Full Text Available Luminal calcium regulates vesicle transport early in the secretory pathway. In ER-to-Golgi transport, depletion of luminal calcium leads to significantly reduced transport and a buildup of budding and newly budded COPII vesicles and vesicle proteins. Effects of luminal calcium on transport may be mediated by cytoplasmic calcium sensors near ER exits sites (ERES. The penta-EF-hand (PEF protein apoptosis-linked gene 2 (ALG-2 stabilizes sec31A at ER exit sites (ERES and promotes the assembly of inner and outer shell COPII components. However, in vitro and intact cell approaches have not determined whether ALG-2 is a negative or positive regulator, or a regulator at all, under basal physiological conditions. ALG-2 interacts with another PEF protein, peflin, to form cytosolic heterodimers that dissociate in response to calcium. However, a biological function for peflin has not been demonstrated and whether peflin and the ALG-2/peflin interaction modulates transport has not been investigated. Using an intact, single cell, morphological assay for ER-to-Golgi transport in normal rat kidney (NRK cells, we found that depletion of peflin using siRNA resulted in significantly faster transport of the membrane cargo VSV-G. Double depletion of peflin and ALG-2 blocked the increased transport resulting from peflin depletion, demonstrating a role for ALG-2 in the increased transport. Furthermore, peflin depletion caused increased targeting of ALG-2 to ERES and increased ALG-2/sec31A interactions, suggesting that peflin may normally inhibit transport by preventing ALG-2/sec31A interactions. This work identifies for the first time a clear steady state role for a PEF protein in ER-to-Golgi transport-peflin is a negative regulator of transport.

  9. Hvad skal danske hospitaler med ungecaféer?

    DEFF Research Database (Denmark)

    Kvisgaard Knudsen, Kristina; Bregnballe, Vibeke

    at forbedre unges oplevelse af at være indlagt, er der i Danmark etableret ungecaféer. Formål: At undersøge ungecaféers betydning for indlagte unge. Metode: Fire semistrukturerede interviews er foretaget med kronisk eller alvorligt syge unge i alderen 11-19 år. De unge har besøgt Café Nexus på Aarhus...

  10. Interaction between magnetic moments and itinerant carriers in d0 ferromagnetic SiC

    Science.gov (United States)

    Liu, Yu; Yuan, Ye; Liu, Fang; Böttger, Roman; Anwand, Wolfgang; Wang, Yutian; Semisalova, Anna; Ponomaryov, Alexey N.; Lu, Xia; N'Diaye, Alpha T.; Arenholz, Elke; Heera, Viton; Skorupa, Wolfgang; Helm, Manfred; Zhou, Shengqiang

    2017-05-01

    Elucidating the interaction between magnetic moments and itinerant carriers is an important step to spintronic applications. Here, we investigate magnetic and transport properties in d0 ferromagnetic SiC single crystals prepared by postimplantation pulsed laser annealing. Magnetic moments are contributed by the p states of carbon atoms, but their magnetic circular dichroism is different from that in semi-insulating SiC samples. The anomalous Hall effect and negative magnetoresistance indicate the influence of d0 spin order on free carriers. The ferromagnetism is relatively weak in N-implanted SiC compared with that in Al-implanted SiC after annealing. The results suggest that d0 magnetic moments and itinerant carriers can interact with each other, which will facilitate the development of SiC spintronic devices with d0 ferromagnetism.

  11. SI - Small Scale Advantages

    OpenAIRE

    Nordström, Marie; Kallin Westin, Lena

    2006-01-01

    Not being part of a larger SI-organisation has both advantages and disadvantages. In this paper we try to illustrate the advantages of doing SI small scale. In a large scale SI-organisation the supervisors are often not teachers themselves and/or not familiar with the practices of a specific course. To have teaching staff supervising a SIproject completely focused on one course is favourable in many ways. The decision to introduce SI was taken by the department of Computing Science to support...

  12. An ER-directed fusion protein comprising a bacterial subtilisin ...

    African Journals Online (AJOL)

    nausch

    cytokine interleukin 6 is efficiently cleaved in planta ... extraction, suggesting that the fusion protein is cleaved in planta by endogenous proteases. ..... harvested 10 days post infiltration with A. tumefaciens strain ICF320 carrying the vectors pICH29912-IL6ER, pICH29912-Subi-IL6ER and plCH29912-Subi-s-IL6ER. Cultivar.

  13. Fjernvarmen er en del af vejen til 100 % vedvarende energi

    DEFF Research Database (Denmark)

    Mathiesen, Brian Vad

    2009-01-01

    Udgivelsesdato: Oktober Det sidste punktum er sat i beregningerne bag IDA’s Klimaplan 2050. Planen er Ingeniørforeningens bud på, hvordan vi kan nedbringe udledningen af drivhusgasser med 90 % i 2050, blive uafhængige af fossile brændsler og lave en omstilling til en økonomi, der er baseret på ve...

  14. Synthesis, characterization, and photoluminescence of Er2O3-Er2SO2 nanoparticles on reduced graphene oxide

    Science.gov (United States)

    Kalugin, Nikolai G.; Roy, Aaron J.; Artyushkova, Kateryna; Serov, Alexey

    2017-05-01

    Thermal reduction of erbium nitrate and S-doped reduced graphene oxide (rGO) mixture resulted in the formation of small (˜3-18 nm sized) Er2O3-Er2SO2 nanoparticles with a high degree of surface coverage on the reduced GO support. The morphology, structure, and the chemical composition of the synthesized nanoparticles have been studied by scanning and transmission electron microscopy, x-ray photoelectron spectroscopy, x-ray diffraction, and by optical spectroscopies. The rGO-supported Er2O3-Er2SO2 nanoparticles (Er2O3-Er2SO2/rGO) demonstrate sufficiently strong light emission (luminescence and upconversion) in the visible and near-infrared range via intra-4f Er3+ optical transitions. The reported synthetic approach demonstrates a novel method for synthesizing Er-containing nanoparticles for sensor applications.

  15. Hybrid systems with Ag nanocrystals and Si nanostructures synthesized by ultra-low-energy ion beam synthesis

    Science.gov (United States)

    Carrada, M.; Haj Salem, A.; Pecassou, B.; Carles, R.; Ben Assayag, G.

    2017-09-01

    Hybrid systems based on silicon and silver nanocrystals (Si-NCs and Ag-NCs) are of considerable interest in photon conversion solar cells. Due to their plasmonic properties, Ag-NCs strongly increase the photoluminescence emission intensity of Si-NCs located in their vicinity, allowing, in principle, to solve the problem of their low emission yield. In this work, we have elaborated 2D networks of Ag-NCs and amorphous Si nanoparticles in a controlled way by using Ultra-Low-Energy Ion-Beam-Synthesis. In the proposed synthesis scheme, a 2D layer of Si-NCs is first obtained by implanting Si+ ions at ultra low energy (from 1 to 3 keV) in a SiO2 layer with subsequent high temperature thermal annealing. Then, Ag+ ions are implanted in the same matrix at energies between 3 and 10 keV and crystalline Ag-NCs are formed during the implantation step. Several configurations with either 2D arrays or a large band of Ag-NCs have been obtained following the Ag+ implantation energy. Enhancement of the PL emission from Si nanostructures, which is related to the presence of Ag-NCs, has been observed under specific arrangement of the two embedded subsystems. In this type of synthesis, a combination of physical phenomena including ion mixing, implantation damage, point defect, and thermal diffusion has been taken into account in order to explain and thus control the structural and the optical characteristics of the system.

  16. A 1-year randomised controlled trial comparing zirconia versus metal-ceramic implant supported single-tooth restorations

    DEFF Research Database (Denmark)

    Hosseini, Mandana; Worsaae, Nils; Schiødt, Morten

    2011-01-01

    PURPOSE: To compare the biological, technical and aesthetic outcomes of single implant-supported all-ceramic versus metal-ceramic crowns. MATERIALS AND METHODS: Thirty-six patients with premolar agenesis were randomly treated with 38 all-ceramic (AC) and 37 metal-ceramic (MC) implant-supported si...

  17. Ion beam synthesis of SiGe alloy layers

    Energy Technology Data Exchange (ETDEWEB)

    Im, Seongil [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    Procedures required for minimizing structural defects generated during ion beam synthesis of SiGe alloy layers were studied. Synthesis of 200 mm SiGe alloy layers by implantation of 120-keV Ge ions into <100> oriented Si wafers yielded various Ge peak concentrations after the following doses, 2 x 1016cm-2, 3 x 1016cm-2 (mid), and 5 x 1016cm-2 (high). Following implantation, solid phase epitaxial (SPE) annealing in ambient N2 at 800C for 1 hr. resulted in only slight redistribution of the Ge. Two kinds of extended defects were observed in alloy layers over 3 x l016cm-2cm dose at room temperature (RT): end-of-range (EOR) dislocation loops and strain-induced stacking faults. Density of EOR dislocation loops was much lower in alloys produced by 77K implantation than by RT implantation. Decreasing the dose to obtain 5 at% peak Ge concentration prevents strain relaxation, while those SPE layers with more than 7 at% Ge peak show high densities of misfit- induced stacking faults. Sequential implantation of C following high dose Ge implantation (12 at% Ge peak concentration in layer) brought about a remarkable decrease in density of misfit-induced stacking faults. For peak implanted C > 0.55 at%, stacking fault generation in the epitaxial layer was suppressed, owing to strain compensation by C atoms in the SiGe lattice. A SiGe alloy layer with 0.9 at% C peak concentration under a 12 at% Ge peak exhibited the best microstructure. Results indicate that optimum Ge/C ratio for strain compensation is between 11 and 22. The interface between amorphous and regrown phases (a/c interface) had a dramatic morphology change during its migration to the surface. Initial <100> planar interface decomposes into a <111> faceted interface, changing the growth kinetics; this is associated with strain relaxation by stacking fault formation on (111) planes in the a/c interface.

  18. Ion Implantation in Ge: Structural and electrical investigation of the induced lattice damage & Study of the lattice location of implanted impurities

    CERN Document Server

    Decoster, Stefan; Wahl, Ulrich

    The past two decades, germanium has drawn international attention as one of the most promising materials to replace silicon in semiconductor applications. Due to important advantages with respect to Si, such as the increased electron and hole mobility, Ge is well on its way to become an important material in future high-speed integrated circuits. Although the interest in this elemental group IV semiconductor is increasing rapidly nowadays, the number of publications about this material is still relatively scarce, especially when compared to Si. The most widely used technique to dope semiconductors is ion implantation, due to its good control of the dopant concentration and profile, and the isotopic purity of the implanted species. However, there is a major lack of knowledge of the fundamental properties of ion implantation in Ge, which has triggered the research presented in this thesis. One of the most important and generally unwanted properties of ion implantation is the creation of damage to the crystal la...

  19. Ellers er det jo bare en stol

    DEFF Research Database (Denmark)

    Hansen, Per H.

    2013-01-01

    Brands. Kan man sælge Georg Jensen-smykker fra Bahrain? Eller Arne Jacobsens myrestole fra Polen? Der er masser af brands, der har fået halen på komedie ved at overse, hvorfor de selv har opnået så stærk en position i første omgang.......Brands. Kan man sælge Georg Jensen-smykker fra Bahrain? Eller Arne Jacobsens myrestole fra Polen? Der er masser af brands, der har fået halen på komedie ved at overse, hvorfor de selv har opnået så stærk en position i første omgang....

  20. Sund livsstil er mere end fysik

    DEFF Research Database (Denmark)

    Nybo, Lars; Thing, Lone Friis; Astrup, Arne

    2015-01-01

    I de seneste dage har man blandt andet i Information kunnet følge Morten Ebbe Juul Nielsens bredside mod, hvad han opfatter som nutidens sundhedsregime. Problemet med Nielsens kritik er, at den tager udgangspunkt i et forældet syn på sundhed, hvor fysisk sundhed sker på bekostning af mental sundhed...... behandling af inaktivitetsrelaterede lidelser bør dog ikke være det vigtigste argument for at oplyse om og opfordre til en sund livsstil. Livskvalitetsaspektet skal være i højsædet, og det er for så vidt en legitim bekymring, at der kommer et overdrevet fokus på samfundsøkonomi og forebyggelse af somatisk...

  1. Tv nyheder: Journalistiske Idealer er under Pres

    DEFF Research Database (Denmark)

    Thomsen, Line Hassall

    2013-01-01

    flittigt. For når der bliver lavet en nyhed som seerne taler om, så vil den også få flere seere – få et ’like’ på Facebook og blive delt på Twitter. Journalisten der har lavet en nyhed der får mange likes bliver måske nævnt i en skulderklappende fællesmail fra nyhedsredaktøren, måske vinder han en flaske...... det helt naturligt at tv-cheferne tænker økonomi. Men at organisere hele nyhedsproduktionen omkring forbrug, priser, clicks, likes og markedslogik kan godt gå hen og være det værste der er sket for public service tv nyhederne. For lige netop journalisternes idealer om God Journalistik er måske det...

  2. Ide. *ger- „kelti“

    Directory of Open Access Journals (Sweden)

    Vytautas Mažiulis

    2011-12-01

    Full Text Available IDG. *ger- „HEBEN, HOCHZIEHEN“ZusammenfassungEinen solchen Archetyp (nämlich mit einer solchen oder ähnlichen Bedeutung gibt es bisher in etymologischen Wörterbüchern der indogermanischen Sprachen noch nicht. Eine solche Rekonst­ruktion ermöglichen aber bestimmte etymologische Gegebenheiten vor allem der baltischen und slawischen Sprachen — dieser besonders archaischen indogermanischen Dialekte. Entschei­dend bei dieser Rekonstruktion ist die im Aufsatz behandelte Etymologie (bisher von niemand er­klärt! der verwandten baltischen und slawischen Wörtern: a preuß. garian „Baum“ (Neutr. < westbalt. *garan (Neutr., b lit. girià (= lett. dziŗa „(Forstenwald“ (Fem. < ostbalt. *girā́ (Fem. und c aksl. (u. a. gora „Berg“ (Fem. < slaw. *garā (Fem.. Es werden Argumente ange­führt, die davon zeugen, daß alle diese baltischen und slawischen Wörter im Altertum „Erhöhung, Erhebung“ bedeuteten, d. h. sie waren Adjektivabstrakta (natürlich singulariatantum! — subs­tantivierte neutr. (westbalt. bzw. fem. (ostbalt. und slaw. Formen der Adjektive mit der Bedeutung „erhöht, herausragend“. Weiter wird gezeigt, daß diese balt.-slaw. Adjektive für Ableitungen zu halten sind [mit den Endungen balt.-slaw. *-as (masc, *-a (neutr., *-ā (fem.] von den For­men (mit dem Ablaut des Wurzervokalismus des Wurzelsubstantivs (der konsonantischen Dekli­nation und generis neutr. < idg. generis imanimati, eines nomen actionis (singulare tantum! mit der Bedeutung „das Emporheben, das Hervor-, Herausragen“, d. h.: a von der Form des Wur­zelnomens balt.-slaw. *gar < idg. *guor bzw. b von der Form des Wurzelnomens + *-i balt.-slaw. *gari / *giri < idg. *gori / *g0ri; von dieser Form idg. Wurzelnomen + *-i stammten i-stäm­mige av. gairiš „Berg, Anhöhe“ / altind. giríṣ „dass.“ u. a. Dieses ncmen actionis (generis inanimati idg. *gor bzw. *gori / *g ori „das Emporheben, das Hervor

  3. Her er din motion i 2012

    DEFF Research Database (Denmark)

    Suhr, Lasse Kristian

    2014-01-01

    Motion i naturen, en indendørs fitnessform inspireret af junglens lianer og høj intensitet med crossfit. Det er ifølge en ekspert nogle af de træningstyper, der vil være mest populære i 2012. Året hvor fleksibilitet og frihed vil blive endnu vigtigere, for den måde vi holder os i form på....

  4. Hvor langt er PISA fra Danmark?

    DEFF Research Database (Denmark)

    Dolin, Jens; Krogh, Lars Brian

    2008-01-01

    I Danmark, såvel som i andre lavtplacerede lande, har PISA haft omfattende mediedækning, og de politiske konsekvenser har været betydelige. Væsentligst i denne sammenhæng er formentlig indførelsen af nationale tests i dansk/læsning, matematik og samtlige naturfag – og med stort fokus på samme ald...

  5. Hamlet er manden i mit liv

    DEFF Research Database (Denmark)

    Rösing, Lilian Munk

    2009-01-01

    Hamlet er manden i mit liv. Min elskede. Jeg har en drøm om at frelse ham. At redde ham ud af sin mors soveværelse og ind i mit. Væk fra det ødipale Helvede han befinder sig i, fastlåst mellem et svin af en faderskikkelse (Claudius) og en alt for idealiseret far (gamle Hamlet), vågende over sin m...

  6. Electrorheological (ER) Fluids: A Research Needs Assessment

    Science.gov (United States)

    1993-05-01

    arising from charges on the particles and modified by the presence and distribution of free ions. Magnetorheological (MR) fluids undergo strong...separate control of cab and trailer motions is probably the way to go. Other automotive uses that may come in the near future include vibration dampers ...this work used very simple fluids offering less than optimum performance, but provided some useful guidelines to damper and clutch design using ER fluids

  7. ER-12-1 completion report

    Energy Technology Data Exchange (ETDEWEB)

    Russell, C.E.; Gillespie, D.; Cole, J.C.; Drellack, S.L. [and others

    1996-12-01

    The objective of drillhole ER-12-1 was to determine the hydrogeology of paleozoic carbonate rocks and of the Eleana Formation, a regional aquitard, in an area potentially downgradient from underground nuclear testing conducted in nearby Rainier Mesa. This objective was addressed through the drilling of well ER-12-1 at N886,640.26 E640,538.85 Nevada Central Coordinates. Drilling of the 1094 m (3588 ft) well began on July 19, 1991 and was completed on October 17, 1991. Drilling problems included hole deviation and hole instability that prevented the timely completion of this borehole. Drilling methods used include rotary tri-cone and rotary hammer drilling with conventional and reverse circulation using air/water, air/foam (Davis mix), and bentonite mud. Geologic cuttings and geophysical logs were obtained from the well. The rocks penetrated by the ER-12-1 drillhole are a complex assemblage of Silurian, Devonian, and Mississippian sedimentary rocks that are bounded by numerous faults that show substantial stratigraphic offset. The final 7.3 m (24 ft) of this hole penetrated an unusual intrusive rock of Cretaceous age. The geology of this borehole was substantially different from that expected, with the Tongue Wash Fault encountered at a much shallower depth, paleozoic rocks shuffled out of stratigraphic sequence, and the presence of an altered biotite-rich microporphyritic igneous rock at the bottom of the borehole. Conodont CAI analyses and rock pyrolysis analyses indicate that the carbonate rocks in ER-12-1, as well as the intervening sheets of Eleana siltstone, have been thermally overprinted following movement on the faults that separate them. The probable source of heat for this thermal disturbance is the microporphyritic intrusion encountered at the bottom of the hole, and its age establishes that the major fault activity must have occurred prior to 102.3+0.5 Ma (middle Cretaceous).

  8. Er energieffektivisering forgæves?

    DEFF Research Database (Denmark)

    Taudal Poulsen, René

    2016-01-01

    Olieprisens bølgegang giver rederierhvervet store muligheder og udfordringer. For to år siden lå prisen på en tønde olie over 100 dollars, og dengang var det vanskeligt at forestille sig et væsentligt fald inden for overskuelig fremtid. I løbet af det sidste halvandet år er vi imidlertid blevet...

  9. Der er en tupilak i rummet

    DEFF Research Database (Denmark)

    Thisted, Kirsten

    2017-01-01

    Tupilakken er et skadesdyr, som man skabte af at gemme på dårlige tanker og energier, der voksede og forvrængede én, så man blev ét med sit eget had. Dette synes stadig at være på spil i forholdet mellem danskere og grønlændere i den 18-årige grønlandske rapper Josef Tarrak Petrussens video Tupilak...

  10. Selskaberne er en del af staten

    DEFF Research Database (Denmark)

    Hein Jessen, Mathias

    2016-01-01

    Lækket af Panama Papers fremhæver endnu engang den paradoksale rolle, ikke mindst multinationale selskaber spiller i politik og økonomi: De er både skabt af staten, og fremstår stadig som uden for og i opposition til staten. Hvis vi vil gøre noget ved problemet, må vi forstå, hvordan stat og...

  11. Virtual Reality er dit nye Skype

    DEFF Research Database (Denmark)

    Bødker, Mads

    2016-01-01

    VR er mediet, der kan gøre den flade skærm og det begrænsede blik i for eksempel Skype til et lidt gammeldags digitalt samarbejde. Ved at sætte folk i stand til at kommunikere, dele virtuelle genstande og give dem en øget oplevelse af at være i et rum sammen, kan man mediere nye aspekter af samar...

  12. Friluftsinstallationer i træer

    DEFF Research Database (Denmark)

    Skov, Simon; Thomsen, Iben Margrete

    2015-01-01

    Abebaner, treetop walking, high rope adventure, slackline, træhuse og parkour-baner er alle installationer, som bruger træerne som støtte, enten midlertidigt eller permanent. Den nye sport, turistattraktionen eller team building-redskabet sætter i alle tilfælde træerne på prøve. Der følger positiv...

  13. Hvem er befrieren? Idealisme og realisme

    DEFF Research Database (Denmark)

    Rabjerg, Bjørn

    2017-01-01

    Artiklen fokuserer på K.E. Løgstrups (1905-81) begreb om forståelse ved at sætte det i perspektiv til (1) Platons Hulelignelse og (2) Martin Heideggers (1889-1976) udlægning af denne. Anliggendet er at pege på den tidlige og formative indvirkning, som Løgstrups møde med Heidegger, nazisme og idea...

  14. Sirt3-Mediated Autophagy Contributes to Resveratrol-Induced Protection against ER Stress in HT22 Cells

    Directory of Open Access Journals (Sweden)

    Wen-Jun Yan

    2018-02-01

    Full Text Available Endoplasmic reticulum (ER stress occurring in stringent conditions is critically involved in neuronal survival and death. Resveratrol is a non-flavonoid polyphenol that has neuroprotective effects against many neurological disorders. Here, we investigated the potential protective effects of resveratrol in an in vitro ER stress model mimicked by tunicamycin (TM treatment in neuronal HT22 cells. We found that TM dose-dependently decreased cell viability and increased apoptosis, which were both significantly attenuated by resveratrol treatment. Resveratrol markedly reduced the expression or activation of ER stress-associated factors, including GRP78, CHOP, and caspase-12. The results of immunocytochemistry and western blot showed that resveratrol promoted autophagy in TM-treated cells, as evidenced by increased LC3II puncta number, bcelin1 expression and LC3II/LC3I ratio. Pretreatment with the autophagy inhibitor chloroquine could reduce the protective effects of resveratrol. In addition, the expression of Sirt3 protein and its downstream enzyme activities were significantly increased in resveratrol-treated HT22 cells. To confirm the involvement of Sirt3-mediated mechanisms, siRNA transfection was used to knockdown Sirt3 expression in vitro. The results showed that downregulation of Sirt3 could partially prevented the autophagy and protection induced by resveratrol after TM treatment. Our study demonstrates a pivotal role of Sirt3-mediated autophagy in mediating resveratrol-induced protection against ER stress in vitro, and suggests the therapeutic values of resveratrol in ER stress-associated neuronal injury conditions.

  15. SYP73 Anchors the ER to the Actin Cytoskeleton for Maintenance of ER Integrity and Streaming in Arabidopsis.

    Science.gov (United States)

    Cao, Pengfei; Renna, Luciana; Stefano, Giovanni; Brandizzi, Federica

    2016-12-05

    The endoplasmic reticulum (ER) is an essential organelle that spreads throughout the cytoplasm as one interconnected network of narrow tubules and dilated cisternae that enclose a single lumen. The ER network undergoes extensive remodeling, which critically depends on membrane-cytoskeleton interactions [1]. In plants, the ER is also highly mobile, and its streaming contributes significantly to the movement of other organelles [2, 3]. The remodeling and motility of the plant ER rely mainly on actin [4] and to a minor extent on microtubules [5]. Although a three-way interaction between the ER, cytosolic myosin-XI, and F-actin mediates the plant ER streaming [6], the mechanisms underlying stable interaction of the ER membrane with actin are unknown. Early electron microscopy studies suggested a direct attachment of the plant ER with actin filaments [7, 8], but it is plausible that yet-unknown proteins facilitate anchoring of the ER membrane with the cytoskeleton. We demonstrate here that SYP73, a member of the plant Syp7 subgroup of SNARE proteins [9] containing actin-binding domains, is a novel ER membrane-associated actin-binding protein. We show that overexpression of SYP73 causes a striking rearrangement of the ER over actin and that, similar to mutations of myosin-XI [4, 10, 11], loss of SYP73 reduces ER streaming and affects overall ER network morphology and plant growth. We propose a model for plant ER remodeling whereby the dynamic rearrangement and streaming of the ER network depend on the propelling action of myosin-XI over actin coupled with a SYP73-mediated bridging, which dynamically anchors the ER membrane with actin filaments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Distinct genes related to drug response identified in ER positive and ER negative breast cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Kui Shen

    Full Text Available Breast cancer patients have different responses to chemotherapeutic treatments. Genes associated with drug response can provide insight to understand the mechanisms of drug resistance, identify promising therapeutic opportunities, and facilitate personalized treatment. Estrogen receptor (ER positive and ER negative breast cancer have distinct clinical behavior and molecular properties. However, to date, few studies have rigorously assessed drug response genes in them. In this study, our goal was to systematically identify genes associated with multidrug response in ER positive and ER negative breast cancer cell lines. We tested 27 human breast cell lines for response to seven chemotherapeutic agents (cyclophosphamide, docetaxel, doxorubicin, epirubicin, fluorouracil, gemcitabine, and paclitaxel. We integrated publicly available gene expression profiles of these cell lines with their in vitro drug response patterns, then applied meta-analysis to identify genes related to multidrug response in ER positive and ER negative cells separately. One hundred eighty-eight genes were identified as related to multidrug response in ER positive and 32 genes in ER negative breast cell lines. Of these, only three genes (DBI, TOP2A, and PMVK were common to both cell types. TOP2A was positively associated with drug response, and DBI was negatively associated with drug response. Interestingly, PMVK was positively associated with drug response in ER positive cells and negatively in ER negative cells. Functional analysis showed that while cell cycle affects drug response in both ER positive and negative cells, most biological processes that are involved in drug response are distinct. A number of signaling pathways that are uniquely enriched in ER positive cells have complex cross talk with ER signaling, while in ER negative cells, enriched pathways are related to metabolic functions. Taken together, our analysis indicates that distinct mechanisms are involved in

  17. In vivo immuno-reactivity analysis of the porous three-dimensional chitosan/SiO2 and chitosan/SiO2 /hydroxyapatite hybrids.

    Science.gov (United States)

    Guo, Mengxia; Dong, Yifan; Xiao, Jiangwei; Gu, Ruicai; Ding, Maochao; Huang, Tao; Li, Junhua; Zhao, Naru; Liao, Hua

    2018-01-03

    Inorganic/organic hybrid silica-chitosan (CS) scaffolds have promising potential for bone defect repair, due to the controllable mechanical properties, degradation behavior, and scaffold morphology. However, the precise in vivo immuno-reactivity of silica-CS hybrids with various compositions is still poorly defined. In this study, we fabricated the three-dimensional (3D) interconnected porous chitosan-silica (CS/SiO2 ) and chitosan-silica-hydroxyapatite (CS/SiO2 /HA) hybrids, through sol-gel process and 3D plotting skill, followed by the naturally or freeze drying separately. Scanning electron microscopy demonstrated the hybrids possessed the uniform geometric structure, while, transmission electron microscopy displayed nanoscale silica, or HA nanoparticles dispersed homogeneously in the CS matrix, or CS/silica hybrids. After intramuscular implantation, CS/SiO2 and CS/SiO2 /HA hybrids triggered a local and limited monocyte/macrophage infiltration and myofiber degeneration. Naturally dried CS/SiO2 hybrid provoked a more severe inflammation than the freeze-dried ones. Dendritic cells were attracted to invade into the implants embedded-muscle, but not be activated to prime the adaptive immunity, because the absence of cytotoxic T cells and B cells in muscle received the implants. Fluorescence-activated cell sorting (FACS) analysis indicated the implanted hybrids were incapable to initiate splenocytes activation. Plasma complement C3 enzyme linked immunosorbent assay (ELISA) assay showed the hybrids induced C3 levels increase in early implanting phase, and the subsequent striking decrease. Thus, the present results suggest that, in vivo, 3D plotted porous CS/SiO2 and CS/SiO2 /HA hybrids are relatively biocompatible in vivo, which initiate a localized inflammatory procedure, instead of a systematic immune response. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2018. © 2018 Wiley Periodicals, Inc.

  18. ER stress, autophagy, and RNA viruses

    Directory of Open Access Journals (Sweden)

    Jia-Rong eJheng

    2014-08-01

    Full Text Available Endoplasmic reticulum (ER stress is a general term for representing the pathway by which various stimuli affect ER functions. ER stress induces the evolutionarily conserved signaling pathways, called the unfolded protein response (UPR, which compromises the stimulus and then determines whether the cell survives or dies. In recent years, ongoing research has suggested that these pathways may be linked to the autophagic response, which plays a key role in the cell’s response to various stressors. Autophagy performs a self-digestion function, and its activation protects cells against certain pathogens. However, the link between the UPR and autophagy may be more complicated. These two systems may act dependently, or the induction of one system may interfere with the other. Experimental studies have found that different viruses modulate these mechanisms to allow them to escape the host immune response or, worse, to exploit the host’s defense to their advantage; thus, this topic is a critical area in antiviral research. In this review, we summarize the current knowledge about how RNA viruses, including influenza virus, poliovirus, coxsackievirus, enterovirus 71, Japanese encephalitis virus, hepatitis C virus, and dengue virus, regulate these processes. We also discuss recent discoveries and how these will produce novel strategies for antiviral treatment.

  19. Effects of LeY glycan expression on embryo implantation.

    Science.gov (United States)

    Gu, J; Sui, L-L; Cui, D; Ma, Y-N; Zhu, C-Y; Kong, Y

    2016-08-01

    To investigate the correlation between LeY glycan expression and embryo implantation. Uterine epithelial cells before implantation were transfected with FUT1siRNA to inhibit FUT1 (the gene encoding the key enzyme of LeY synthesis) expression and treated with 10 ng/ml leukemia inhibitory factor (LIF). Murine embryo implantation model in vitro was prepared by late blastocysts with identical morphology and treated uterine epithelial cells co-culture. Using RT-PCR, dot blot and observation of embryo attachment to analyze FUT1 gene expression and LeY synthesis of uterine epithelial cells and studied further the correlation of LeY expression level and embryo implantation. FUT1 gene expression and LeY synthesis declined after cells were transfected with FUT1siRNA, and LIF promoted FUT1 expression and LeY synthesis. After expression of FUT1 gene was inhibited, attachment rate of embryos lowered, but LIF up-regulated FUT1 expression and increased the attachment rate of embryos. These results indicated regulating FUT1 expression affected LeY synthesis, and then LeY regulated the recognition and attachment of uterus-embryo and participates in embryo implantation further.

  20. Dental Implant Systems

    Science.gov (United States)

    Oshida, Yoshiki; Tuna, Elif B.; Aktören, Oya; Gençay, Koray

    2010-01-01

    Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities. PMID:20480036

  1. Implants in the hand; Implantate der Hand

    Energy Technology Data Exchange (ETDEWEB)

    Wanivenhaus, A. [Medizinische Universitaet, Universitaetsklinik fuer Orthopaedie, Wien (Austria)

    2006-09-15

    Increasingly, implants in the region of hand joints and the wrist represent an alternative for the treatment of post-traumatic, inflamed, or degenerative joint damage. The diversity of hand functions also results in varied solutions, which are effective in their stability, mobility, and distraction. Different materials are necessary for this, and they require subtile radiological control. The native X-ray represents the substantial method to observe migration of the implants. Each interface between titanium, ceramic, zirconium, pyrocarbon, and silicon to the bone has to be assessed differently in order to obtain a relevant statement. The finger joints and to a limited extent the wrist represent the artificial joints with limited alternative therapy. Other implants in the hand should only be applied after strict indication and patient compliance, as arthrodesis and resection arthroplasty have shown very good long-term results. (orig.) [German] Implantate im Bereich der Gelenke der Hand und des Handgelenks stellen zunehmend Alternativen bei der Versorgung posttraumatischer, entzuendlicher oder degenerativer Gelenkschaeden dar. Die Vielfalt der Handfunktionen fuehrt auch zu unterschiedlichen Loesungen, die durch Stabilitaet, Mobilitaet und Distraktion wirksam werden. Dafuer sind unterschiedliche Materialien erforderlich, die eine subtile radiologische Kontrolle erfordern. Das Nativroentgen stellt das wesentlichste Verfahren zur Verlaufsbeobachtung von Implantaten dar. Das Interface zwischen Titan, Keramik, Zirkonium, Pyrokarbon und Silikon zum Knochen muss unterschiedlich bewertet werden, um relevante Aussagen treffen zu koennen. Die Fingergelenke und in begrenztem Ausmass auch das Handgelenk stellen Kunstgelenke mit geringen Alternativtherapiemoeglichkeiten dar. Die uebrigen Implantate der Hand sollten nur bei strenger Indikationsstellung und hoher Patientencompliance Anwendung finden, da Arthrodese oder Resektionsarthroplastik gute Langzeitresultate aufweisen. (orig.)

  2. MicroRNAs meet calcium: joint venture in ER proteostasis.

    Science.gov (United States)

    Finger, Fabian; Hoppe, Thorsten

    2014-11-04

    The endoplasmic reticulum (ER) is a cellular compartment that has a key function in protein translation and folding. Maintaining its integrity is of fundamental importance for organism's physiology and viability. The dynamic regulation of intraluminal ER Ca(2+) concentration directly influences the activity of ER-resident chaperones and stress response pathways that balance protein load and folding capacity. We review the emerging evidence that microRNAs play important roles in adjusting these processes to frequently changing intracellular and environmental conditions to modify ER Ca(2+) handling and storage and maintain ER homeostasis. Copyright © 2014, American Association for the Advancement of Science.

  3. Nanocrystalline SiC and Ti3SiC2 Alloys for Reactor Materials: Diffusion of Fission Product Surrogates

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Jiang, Weilin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-11-01

    MAX phases, such as titanium silicon carbide (Ti3SiC2), have a unique combination of both metallic and ceramic properties, which make them attractive for potential nuclear applications. Ti3SiC2 has been suggested in the literature as a possible fuel cladding material. Prior to the application, it is necessary to investigate diffusivities of fission products in the ternary compound at elevated temperatures. This study attempts to obtain relevant data and make an initial assessment for Ti3SiC2. Ion implantation was used to introduce fission product surrogates (Ag and Cs) and a noble metal (Au) in Ti3SiC2, SiC, and a dual-phase nanocomposite of Ti3SiC2/SiC synthesized at PNNL. Thermal annealing and in-situ Rutherford backscattering spectrometry (RBS) were employed to study the diffusivity of the various implanted species in the materials. In-situ RBS study of Ti3SiC2 implanted with Au ions at various temperatures was also performed. The experimental results indicate that the implanted Ag in SiC is immobile up to the highest temperature (1273 K) applied in this study; in contrast, significant out-diffusion of both Ag and Au in MAX phase Ti3SiC2 occurs during ion implantation at 873 K. Cs in Ti3SiC2 is found to diffuse during post-irradiation annealing at 973 K, and noticeable Cs release from the sample is observed. This study may suggest caution in using Ti3SiC2 as a fuel cladding material for advanced nuclear reactors operating at very high temperatures. Further studies of the related materials are recommended.

  4. Laser Treatment of Peri-Implantitis: A Literature Review

    Science.gov (United States)

    Ashnagar, Sajjad; Nowzari, Hessam; Nokhbatolfoghahaei, Hanieh; Yaghoub Zadeh, Behnoush; Chiniforush, Nasim; Choukhachi Zadeh, Nastaran

    2014-01-01

    Peri-implantitis is a state defined as an inflammatory reaction around osseointegrated implants, leading to progressive loss of supporting bone. Various treatment methods are suggested in the treatment of peri-implantitis and clinicians have to choose a method over a large number of treatment protocols. Lasers have shown promising therapeutic effect in treatment of peri-implantitis. However, some controversies have been found in clinical outcomes after using lasers. Therefore, we aimed to review the current literature over the past ten years for the use of lasers in treatment of peri-implantitis, via the Pubmed electronic database of the US National Library of Medicine. Fifteen human studies were reviewed. Er:YAG (Erbium-Doped Yttrium Aluminum Garnet), CO2(Carbon Dioxide Laser) and Diode lasers were used. Despite inconsistencies and disharmonies among studies in terms of study design, positive treatment outcomes were obvious among the majority of them. However, short period of follow-ups and poor control of plaque index, as a critical confounding factor, were the major problems which these studies suffered from. It seems that one session laser therapy is not adequate for achieving optimal clinical outcome. Further studies with longer periods of follow-ups, intense control of plaque index, and various sessions of laser treatments are needed to clearly illustrate the clinical privilege of laser therapy. PMID:25653815

  5. Development of a new comprehensive and reliable endometrial receptivity map (ER Map/ER Grade) based on RT-qPCR gene expression analysis.

    Science.gov (United States)

    Enciso, M; Carrascosa, J P; Sarasa, J; Martínez-Ortiz, P A; Munné, S; Horcajadas, J A; Aizpurua, J

    2018-02-01

    Is it possible to determine the receptivity status of an endometrium by combined quantitative reverse transcription PCR (RT-qPCR) expression analysis of genes involved in endometrial proliferation and immunity? The new ER Map®/ER Grade® test can predict endometrial receptivity status by RT-qPCR using a new panel of genes involved in endometrial proliferation and the maternal immune response associated to embryonic implantation. The human endometrium reaches a receptive status adequate for embryonic implantation around Days 19-21 of the menstrual cycle. During this period, known as the window of implantation (WOI), the endometrium shows a specific gene expression profile suitable for endometrial function evaluation. The number of molecular diagnostic tools currently available to characterize this process is very limited. In this study, a new system for human endometrial receptivity evaluation was optimized and presented for the first time. ER Map®/ER Grade® validation was achieved on 312 endometrial samples including fertile women and patients undergoing fertility treatment between July 2014 and March 2016. Expression analyses of 184 genes involved in endometrial receptivity and immune response were performed. Samples were additionally tested with an independent endometrial receptivity test. A total of 96 fertile women and 120 assisted reproduction treatment (ART) patients participated in the study. Endometrial biopsy samples were obtained at LH + 2 and LH + 7 days in fertile subjects in a natural cycle and at the window of implantation (WOI) in patients in a hormone-replacement therapy (HRT) cycle. Total RNA was purified, quality-checked and reverse-transcribed. Gene expression was quantified by high-throughput RT-qPCR and statistically analyzed. Informative genes were selected and used to classify samples into four different groups of endometrial receptivity status. Significantly different gene expression levels were found in 85 out of 184 selected genes when

  6. Smoking and dental implants

    OpenAIRE

    Kasat, V.; Ladda, R

    2012-01-01

    Smoking is a prevalent behaviour in the population. The aim of this review is to bring to light the effects of smoking on dental implants. These facts will assist dental professionals when implants are planned in tobacco users. A search of “PubMed” was made with the key words “dental implant,” “nicotine,” “smoking,” “tobacco,” and “osseointegration.” Also, publications on tobacco control by the Government of India were considered. For review, only those articles published from 1988 onward in ...

  7. Optimization of dental implantation

    Science.gov (United States)

    Dol, Aleksandr V.; Ivanov, Dmitriy V.

    2017-02-01

    Modern dentistry can not exist without dental implantation. This work is devoted to study of the "bone-implant" system and to optimization of dental prostheses installation. Modern non-invasive methods such as MRI an 3D-scanning as well as numerical calculations and 3D-prototyping allow to optimize all of stages of dental prosthetics. An integrated approach to the planning of implant surgery can significantly reduce the risk of complications in the first few days after treatment, and throughout the period of operation of the prosthesis.

  8. Æstetik er tilbage som nøgle til at forstå samtiden

    DEFF Research Database (Denmark)

    Sharma, Devika

    2013-01-01

    Casper Christensen er gakket, Hello Kitty er nuttet og konceptkunsten er interessant. Her er tre nye kategorier at forstå senkapitalismen med. I anledning af Sianne Ngais bog "Our aesthetic categories: zany, cute, interesting" .......Casper Christensen er gakket, Hello Kitty er nuttet og konceptkunsten er interessant. Her er tre nye kategorier at forstå senkapitalismen med. I anledning af Sianne Ngais bog "Our aesthetic categories: zany, cute, interesting" ....

  9. DEALING WITH DENTAL IMPLANT FAILURES

    Science.gov (United States)

    Levin, Liran

    2008-01-01

    An implant-supported restoration offers a predictable treatment for tooth replacement. Reported success rates for dental implants are high. Nevertheless, failures that mandate immediate implant removal do occur. The consequences of implant removal jeopardize the clinician's efforts to accomplish satisfactory function and esthetics. For the patient, this usually involves further cost and additional procedures. The aim of this paper is to describe different methods and treatment modalities to deal with dental implant failure. The main topics for discussion include identifying the failing implant, implants replacing failed implants at the exact site, and the use of other restorative options. When an implant fails, a tailor made treatment plan should be provided to each patient according to all relevant variables. Patients should be informed regarding all possible treatment modalities following implant failure and give their consent to the most appropriate treatment option for them. PMID:19089213

  10. Dealing with dental implant failures

    Directory of Open Access Journals (Sweden)

    Liran Levin

    2008-06-01

    Full Text Available An implant-supported restoration offers a predictable treatment for tooth replacement. Reported success rates for dental implants are high. Nevertheless, failures that mandate immediate implant removal do occur. The consequences of implant removal jeopardize the clinician's efforts to accomplish satisfactory function and esthetics. For the patient, this usually involves further cost and additional procedures. The aim of this paper is to describe different methods and treatment modalities to deal with dental implant failure. The main topics for discussion include identifying the failing implant, implants replacing failed implants at the exact site, and the use of other restorative options.When an implant fails, a tailor made treatment plan should be provided to each patient according to all relevant variables. Patients should be informed regarding all possible treatment modalities following implant failure and give their consent to the most appropriate treatment option for them.

  11. Influence of surface coating on structural, morphological and optical properties of upconversion-luminescent LaF3:Yb/Er nanoparticles

    Science.gov (United States)

    Ansari, Anees A.; Yadav, Ranvijay; Rai, S. B.

    2016-07-01

    LaF3:Yb/Er (core), LaF3:Yb/Er@LaF3 (core/shell) and LaF3:Yb/Er@LaF3@SiO2 (core/shell/SiO2) nanoparticles were synthesized using citric-acid-based complexation process. X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray analysis, optical absorption, band-gap energy ( E g), Fourier transform infrared and upconversion emission spectroscopy were employed to investigate the structural, morphological and optical properties of the synthesized core and core/shell/SiO2 nanoparticles. These core/shell/SiO2 nanoparticles can be well dispersed in aqueous solvents to form clear colloidal solution. The optical band-gap energy was decreased after shell formation due to increase in the crystalline size. The growth of an inactive and porous silica layers simultaneously on the surface of luminescent core-nanoparticles resulting an increase in average crystalline size of the nanoparticles. As-prepared inert shell-coated core/shell nanoparticles show intensive upconversion-luminescence as compared to the seed-core and silica-surface-modified core/shell/SiO2 nanoparticles because luminescent ions (Yb3+ and Er3+) ions located at the particle surface were protected from the non-radiative decay arising from surface dangling bonds and capping agent. However, our study revealed that there was only a slight reduction in upconversion efficiency for the silica-modified core/shell nanoparticles, indicating that upconversion properties of the upconversion nanoparticles are largely preserved in the core/shell/SiO2 nanoparticles. Absorption and upconversion-luminescence properties were examined for future application in the development of optical devices as well as optical bioprobes.

  12. Risks of Breast Implants

    Science.gov (United States)

    ... Tissue Disease The FDA has not detected any association between silicone gel-filled breast implants and connective tissue disease, breast cancer, or reproductive problems. In order to rule out ...

  13. Superelastic Orthopedic Implant Coatings

    Science.gov (United States)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  14. Implantable Cardioverter Defibrillator

    Science.gov (United States)

    ... for example, iPods) Household appliances, such as microwave ovens High-tension wires Metal detectors Industrial welders Electrical ... of Having an Implantable Cardioverter Defibrillator? An ICD works well at detecting and stopping certain life-threatening ...

  15. Ion Implantation of Polymers

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2012-01-01

    The current paper presents a state-of-the-art review in the field of ion implantation of polymers. Numerous published studies of polymers modified by ion beams are analysed. General aspects of ion stopping, latent track formation and changes of structure and composition of organic materials...... are discussed. Related to that, the effects of radiothermolysis, degassing and carbonisation are considered. Specificity of depth distributions of implanted into polymers impurities is analysed and the case of high-fluence implantation is emphasised. Within rather broad topic of ion bombardment, the focus...... is put on the low-energy implantation of metal ions causing the nucleation and growth of nanoparticles in the shallow polymer layers. Electrical, optical and magnetic properties of metal/polymer composites are under the discussion and the approaches towards practical applications are overviewed....

  16. Protectin DX suppresses hepatic gluconeogenesis through AMPK-HO-1-mediated inhibition of ER stress.

    Science.gov (United States)

    Jung, Tae Woo; Kim, Hyung-Chun; Abd El-Aty, A M; Jeong, Ji Hoon

    2017-06-01

    Several studies have shown that protectins, which are ω-3 fatty acid-derived proresolution mediators, may improve insulin resistance. Recently, protectin DX (PDX) was documented to attenuate insulin resistance by stimulating IL-6 expression in skeletal muscle, thereby regulating hepatic gluconeogenesis. These findings made us investigate the direct effects of PDX on hepatic glucose metabolism in the context of diabetes. In the current study, we show that PDX regulates hepatic gluconeogenesis in a manner distinct from its indirect glucoregulatory activity via IL-6. We found that PDX stimulated AMP-activated protein kinase (AMPK) phosphorylation, thereby inducing heme oxygenase 1 (HO-1) expression. This induction blocked hepatic gluconeogenesis by suppressing endoplasmic reticulum (ER) stress in hepatocytes under hyperlipidemic conditions. These effects were significantly dampened by silencing AMPK or HO-1 expression with small interfering RNA (siRNA). We also demonstrated that administration of PDX to high fat diet (HFD)-fed mice resulted in increased hepatic AMPK phosphorylation and HO-1 expression, whereas hepatic ER stress was substantially attenuated. Furthermore, PDX treatment suppressed the expression of gluconeogenic genes, thereby decreasing blood glucose levels in HFD-fed mice. In conclusion, our findings suggest that PDX inhibits hepatic gluconeogenesis via AMPK-HO-1-dependent suppression of ER stress. Thus, PDX may be an effective therapeutic target for the treatment of insulin resistance and type 2 diabetes through the regulation of hepatic gluconeogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Relationship between RUNX1 and AXIN1 in ER-negative versus ER-positive Breast Cancer.

    Science.gov (United States)

    Chimge, Nyam-Osor; Ahmed-Alnassar, Sara; Frenkel, Baruch

    2017-02-16

    RUNX1 plays opposing roles in breast cancer: a tumor suppressor in estrogen receptor-positive (ER+) disease and an oncogenic role in ER-negative (ER-) tumors. Potentially mediating the former, we have recently reported that RUNX1 prevents estrogen-driven suppression of the mRNA encoding the tumor suppressor AXIN1. Accordingly, AXIN1 protein expression was diminished upon RUNX1 silencing in ER+ breast cancer cells and was positively correlated with AXIN1 protein expression across tumors with high levels of ER. Here we report the surprising observation that RUNX1 and AXIN1 proteins are strongly correlated in ER- tumors as well. However, this correlation is not attributable to regulation of AXIN1 by RUNX1 or vice versa. The unexpected correlation between RUNX1, playing an oncogenic role in ER- breast cancer, and AXIN1, a well-established tumor suppressor hub, may be related to a high ratio between the expression of variant 2 and variant 1 (v2/v1) of AXIN1 in ER- compared with ER+ breast cancer. Although both isoforms are similarly regulated by RUNX1 in estrogen-stimulated ER+ breast cancer cells, the higher v2/v1 ratio in ER- disease is expected to weaken the tumor suppressor activity of AXIN1 in these tumors.

  18. [Osteoradionecrosis and dental implants].

    Science.gov (United States)

    Ben Slama, L; Hasni, W; De Labrouhe, C; Bado, F; Bertrand, J-C

    2008-12-01

    Osteoradionecrosis (ORN) is a severe complication of radiation therapy (RT). A triggering factor is frequently present. It is often a dental, periodental, or surgical traumatism. We report the case of a bilateral ORN: the first lesion appeared 3months after the end of RT around the osteosynthesis plate and was treated by mandibular resection. The second lesion appeared 40months after RT on the opposite side, due to peri-implantitis. Dental implants had been inserted 10years before cancer therapy. No case of ORN in post-implantation RT had been previously reported. A 75-year-old woman was admitted for a squamous cell carcinoma of the right cheek extending to the intermaxillary commissure, the maxillary tuberosity, the soft palate, the lingual junction, and the vestibule up to the second premolar area. There was no suspicious lymph node. She had undergone dental implant procedure 15 and 10 years before, respectively, one in the second premolar position of the right maxilla and four in the premolar and molar left mandible area. All of them were osseo-integrated and charged. A trans-mandibular buccopharyngectomy with modified radical neck dissection was performed, completed by RT. The total dose of irradiation was 65Gy in the oral cavity and 45Gy on cervical and supraclavicular areas. Delayed mucosal healing was observed on the right mandible and ORN appeared in this area 3months after the end of irradiation. Mandibular resection was necessary. Later, the right maxillary implant was lost, and multiple dental extractions were required. Forty months after RT, peri-implantitis was observed on the left side of the mandible, complicated by ORN and pathological fracture. No surgical reconstruction could be performed because of the patient's age and state. The patient was carrying a complete removable maxillary prosthesis on latest follow-up. This was the first case of ORN on dental implants placed before RT. RT is a risk factor of implant failure, a relatively rare and

  19. The role of angiogenesis, inflammation and estrogen receptors in breast implant capsules development and remodeling.

    Science.gov (United States)

    Segreto, Francesco; Carotti, Simone; Marangi, Giovanni Francesco; Tosi, Daniele; Zingariello, Maria; Pendolino, Alfonso Luca; Sancillo, Laura; Morini, Sergio; Persichetti, Paolo

    2017-12-13

    Capsular contracture is the most common complication following breast implant placement. The multiple factors unbalancing the physiological response to the foreign body have not been fully elucidated. The aim of this study was to investigate the role of neo-angiogenesis, inflammation and estrogen receptors in peri-prosthetic tissue development and remodeling. The study enrolled 31 women who underwent expander substitution with definitive implant. Specimens were stained with hematoxylin/eosin, Masson trichrome, immunohistochemistry and immunofluorescence for alpha-smooth muscle actin, estrogen receptor-α (ER-α), estrogen receptor-β (ER-β), Collagen type I and III, CD31 (as a marker of neo-angiogenesis) and vascular endothelial growth factor (VEGF). Inflammatory infiltration was quantified and analyzed. Transmission electron microscopy was performed for ultrastructural evaluation. Myofibroblasts, mainly localized in the middle layer of capsular tissue, expressed VEGF, ER-α and ER-β. ER-β expression positively correlated with Collagen type I deposition (p= 0.025). Neo-angiogenesis was predominant in the middle layer. CD31 expression positively correlated with Collagen type I expression (p=0.009) and inflammatory infiltration grade (p= 0.004). The degree of inflammatory infiltration negatively correlated with the time from implantation (p = 0.022). The middle layer is key in the development and remodeling of capsular tissue. Myofibroblasts produce VEGF, that induces neo-angiogenesis. New vessels formation is also correlated to the inflammatory response. Collagen deposition is associated with ER-β expression and neo-angiogenesis. These findings may prelude to targeted pharmacologic therapies able to control such interactions, thus hampering the self-sustaining loop promoting the progression of physiologic fibrosis toward pathologic contracture. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier

  20. Overview of the HIT-SI3 spheromak experiment

    Science.gov (United States)

    Hossack, A. C.; Jarboe, T. R.; Chandra, R. N.; Morgan, K. D.; Sutherland, D. A.; Everson, C. J.; Penna, J. M.; Nelson, B. A.

    2017-10-01

    The HIT-SI and HIT-SI3 spheromak experiments (a = 23 cm) study efficient, steady-state current drive for magnetic confinement plasmas using a novel method which is ideal for low aspect ratio, toroidal geometries. Sustained spheromaks show coherent, imposed plasma motion and low plasma-generated mode activity, indicating stability. Analysis of surface magnetic fields in HIT-SI indicates large n = 0 and 1 mode amplitudes and little energy in higher modes. Within measurement uncertainties all the n = 1 energy is imposed by the injectors, rather than being plasma-generated. The fluctuating field imposed by the injectors is sufficient to sustain the toroidal current through dynamo action whereas the plasma-generated field is not (Hossack et al., Phys. Plasmas, 2017). Ion Doppler spectroscopy shows coherent, imposed plasma motion inside r 10 cm in HIT-SI and a smaller volume of coherent motion in HIT-SI3. Coherent motion indicates the spheromak is stable and a lack of plasma-generated n = 1 energy indicates the maximum q is maintained below 1 for stability during sustainment. In HIT-SI3, the imposed mode structure is varied to test the plasma response (Hossack et al., Nucl. Fusion, 2017). Imposing n = 2, n = 3, or large, rotating n = 1 perturbations is correlated with transient plasma-generated activity. Work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, under Award Number DE-FG02-96ER54361.