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Sample records for phosphorus-ion implanted synthetic

  1. Temperature-dependant study of phosphorus ion implantation in germanium

    NASA Astrophysics Data System (ADS)

    Razali, M. A.; Smith, A. J.; Jeynes, C.; Gwilliam, R. M.

    2012-11-01

    We present experimental results on shallow junction formation in germanium by phosphorus ion implantation and standard rapid thermal processing. An attempt is made to improve phosphorus activation by implanting phosphorus at high and low temperature. The focus is on studying the germanium damage and phosphorus activation as a function of implant temperature. Rutherford backscattering spectrometry with channelling and Hall Effect measurements are employed for characterisation of germanium damage and phosphorus activation, respectively. High and low temperature implants were found to be better compared to room temperature implant.

  2. Effect of phosphorus-ion implantation on the corrosion resistance and biocompatibility of titanium.

    PubMed

    Krupa, D; Baszkiewicz, J; Kozubowski, J A; Barcz, A; Sobczak, J W; Biliński, A; Lewandowska-Szumieł, M; Rajchel, B

    2002-08-01

    This work presents data on the structure and corrosion resistance of titanium after phosphorus-ion implantation with a dose of 10(17)P/cm2. The ion energy was 25keV. Transmission electron microscopy was used to investigate the microstructure of the implanted layer. The chemical composition of the surface layer was examined by X-ray photoelectron spectroscopy and secondary ion mass spectrometry. The corrosion resistance was examined by electrochemical methods in a simulated body fluid at a temperature of 37 C. Biocompatibility tests in vitro were performed in a culture of human derived bone cells in direct contact with the materials tested. Both, the viability of the cells determined by an XTT assay and activity of the cells evaluated by alkaline phosphatase activity measurements in contact with implanted and non-implanted titanium samples were detected. The morphology of the cells spread on the surface of the materials examined was also observed. The results confirmed the biocompatibility of both phosphorus-ion-implanted and non-implanted titanium under the conditions of the experiment. As shown by transmission electron microscope results, the surface layer formed during phosphorus-ion implantation was amorphous. The results of electrochemical examinations indicate that phosphorus-ion implantation increases the corrosion resistance after short-term as well as long-term exposures.

  3. Decrease in work function of transparent conducting ZnO tin films by phosphorus ion implantation.

    PubMed

    Heo, Gi-Seok; Hong, Sang-Jin; Park, Jong-Woon; Choi, Bum-Ho; Lee, Jong-Ho; Shin, Dong-Chan

    2008-09-01

    To confirm the possibility of engineering the work function of ZnO thin films, we have implanted phosphorus ions into ZnO thin films deposited by radio-frequency magnetron sputtering. The fabricated films show n-type characteristics. It is shown that the electrical and optical properties of those thin films vary depending sensitively on the ion dose and rapid thermal annealing time. Compared to as-deposited ZnO films, the work-function of phosphorus ion-implanted ZnO thin films is observed to be lower and decreases with increasing ion doses. It is likely that the zinc or oxygen vacancies are firstly filled with the implanted phosphorus ions. With further increased ions, free electrons are generated as Zn2+ sites are replaced by those ions or interstitial phosphorus ions increase at the lattice sites, the fermi level by which approaches the conduction band and thus the work function decreases. Those films exhibit the optical transmittance higher than 85% within the visible wavelength range (up to 800 nm).

  4. Effect of phosphorus ion implantation on back gate effect of partially depleted SOI NMOS under total dose radiation

    NASA Astrophysics Data System (ADS)

    Leilei, Li; Xinjie, Zhou; Zongguang, Yu; Qing, Feng

    2015-01-01

    The mechanism of improving the TID radiation hardened ability of partially depleted silicon-on-insulator (SOI) devices by using the back-gate phosphorus ion implantation technology is studied. The electron traps introduced in SiO2 near back SiO2/Si interface by phosphorus ions implantation can offset positive trapped charges near the back-gate interface. The implanted high concentration phosphorus ions can greatly reduce the back-gate effect of a partially depleted SOI NMOS device, and anti-total-dose radiation ability can reach the level of 1 Mrad(Si) for experimental devices.

  5. Effect of calcium and phosphorus ion implantation on the corrosion resistance and biocompatibility of titanium.

    PubMed

    Krupa, D; Baszkiewicz, J; Kozubowski, J A; Lewandowska-Szumieł, M; Barcz, A; Sobczak, J W; Biliński, A; Rajchel, A

    2004-01-01

    This paper is concerned with the corrosion resistance and biocompatibility of titanium after surface modification by the ion implantation of calcium or phosphorus or calcium + phosphorus. Calcium and phosphorus ions were implanted in a dose of 10(17) ions/cm(2). The ion beam energy was 25 keV. The microstructure of the implanted layers was examined by TEM. The chemical composition of the surface layers was determined by XPS and SIMS. The corrosion resistance was examined by electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 degrees C. The biocompatibility was evaluated in vitro. As shown by TEM results, the surface layers formed during calcium, phosphorus and calcium + phosphorus implantation were amorphous. The results of the electrochemical examinations (Stern's method) indicate that the calcium, phosphorus and calcium + phosphorus implantation into the surface of titanium increases its corrosion resistance in stationary conditions after short- and long-term exposures in SBF. Potentiodynamic tests show that the calcium-implanted samples undergo pitting corrosion during anodic polarisation. The breakdown potentials measured are high (2.5 to 3 V). The good biocompatibility of all the investigated materials was confirmed under the specific conditions of the applied examination, although, in the case of calcium implanted titanium it was not as good as that of non-implanted titanium.

  6. Understanding and engineering of NiGe/Ge junction formed by phosphorus ion implantation after germanidation

    SciTech Connect

    Oka, Hiroshi Minoura, Yuya; Hosoi, Takuji; Shimura, Takayoshi; Watanabe, Heiji

    2014-08-11

    Modulation of the effective electron Schottky barrier height (eSBH) of NiGe/Ge contacts induced by phosphorus ion implantation after germanide formation was investigated by considering local inhomogeneity in the eSBH. Systematic studies of NiGe/Ge contact devices having various germanide thicknesses and ion implantation areas indicated the threshold dopant concentration at the NiGe/Ge interface required for eSBH modulation and negligible dopant diffusion even at NiGe/Ge interface during drive-in annealing, leading to variation in the eSBH between the bottom and sidewall portions of the NiGe regions. Consequently, this method makes it possible to design source/drain contacts with low-resistivity Ohmic and ideal rectifying characteristics for future Ge-based transistors.

  7. Effect of laser annealing using high repetition rate pulsed laser on optical properties of phosphorus-ion-implanted ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Shimogaki, Tetsuya; Ofuji, Taihei; Tetsuyama, Norihiro; Okazaki, Kota; Higashihata, Mitsuhiro; Nakamura, Daisuke; Ikenoue, Hiroshi; Asano, Tanemasa; Okada, Tatsuo

    2013-03-01

    The effect of high repetition rate pulsed laser annealing with a KrF excimer laser on the optical properties of phosphorus-ion-implanted zinc oxide nanorods has been investigated. The recovery levels of phosphorus-ion-implanted zinc oxide nanorods have been measured by photoluminescence spectra and cathode luminescence images. Cathode luminescence disappeared over 300 nm below the surface due to the damage caused by ion implantation with an acceleration voltage of 25 kV. When the annealing was performed at a low repetition rate of the KrF excimer laser, cathode luminescence was recovered only in a shallow area below the surface. The depth of the annealed area was increased along with the repetition rate of the annealing laser. By optimizing the annealing conditions such as the repetition rate, the irradiation fluence and so on, we have succeeded in annealing the whole damaged area of over 300 nm in depth and in observing cathode luminescence. Thus, the effectiveness of high repetition rate pulsed laser annealing on phosphorus-ion-implanted zinc oxide nanorods was demonstrated.

  8. Effect of laser annealing using high repetition rate pulsed laser on optical properties of phosphorus-ion-implanted ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Shimogaki, Tetsuya; Ofuji, Taihei; Tetsuyama, Norihiro; Okazaki, Kota; Higashihata, Mitsuhiro; Nakamura, Daisuke; Ikenoue, Hiroshi; Asano, Tanemasa; Okada, Tatsuo

    2014-02-01

    The effect of high repetition rate pulsed laser annealing with a KrF excimer laser on the optical properties of phosphorus-ion-implanted zinc oxide nanorods has been investigated. The recovery levels of phosphorus-ion-implanted zinc oxide nanorods have been measured by photoluminescence spectra and cathode luminescence images. Cathode luminescence disappeared over 300 nm below the surface due to the damage caused by ion implantation with an acceleration voltage of 25 kV. When the annealing was performed at a low repetition rate of the KrF excimer laser, cathode luminescence was recovered only in a shallow area below the surface. The depth of the annealed area was increased along with the repetition rate of the annealing laser. By optimizing the annealing conditions such as the repetition rate, the irradiation fluence and so on, we have succeeded in annealing the whole damaged area of over 300 nm in depth and in observing cathode luminescence. Thus, the effectiveness of high repetition rate pulsed laser annealing on phosphorus-ion-implanted zinc oxide nanorods was demonstrated.

  9. Preparation of radiotherapy glass by phosphorus ion implantation at 100 keV.

    PubMed

    Kawashita, M; Miyaji, F; Kokubo, T; Takaoka, G H; Yamada, I; Suzuki, Y; Kajiyama, K

    1997-01-01

    A chemically durable glass containing a large amount of phosphorus is useful for in situ irradiation of cancers. It can be activated to be a beta emitter (half-life of 14.3 days) by neutron bombardment. Microspheres of the activated glass injected into the tumors can irradiate the tumors directly with beta rays without irradiating neighboring normal tissues. In the present study a P+ ion was implanted into a pure silica glass in a plate form at 100 keV in order to find the fundamental conditions for obtaining such a glass. Little phosphorus was present in the surface region, at least to a depth of 2.4 nm for doses of 5 x 10(16) and 1 x 10(17) cm-2, whereas an appreciable amount of it was distributed on the glass surface and a part of it was oxidized for doses above 5 x 10(17) cm-2. The glasses implanted with doses of 5 x 10(16) and 1 x 10(17) cm-2 hardly released the P and Si into water at 95 degrees C, even after 7 days, whereas the glasses implanted with doses above 5 x 10(17) cm-2 released appreciable amounts of these elements. Implantation energies of 20 and 50 keV (even at doses of 5 x 10(16) and 1 x 10(17) cm-2, respectively), formed oxidized phosphorus on the glass surfaces and gave appreciable release of the P and Si into the hot water. This indicates that a chemically durable glass containing a larger amount of phosphorus could be obtained if a P+ ion is implanted at higher energies to localize in a deeper region of the glass surface.

  10. Towards simultaneous achievement of carrier activation and crystallinity in Ge and GeSn with heated phosphorus ion implantation: An optical study

    NASA Astrophysics Data System (ADS)

    D'Costa, Vijay Richard; Wang, Lanxiang; Wang, Wei; Lim, Sin Leng; Chan, Taw Kuei; Chua, Lye Hing; Henry, Todd; Zou, Wei; Hatem, Christopher; Osipowicz, Thomas; Tok, Eng Soon; Yeo, Yee-Chia

    2014-09-01

    We have investigated the optical properties of Ge and GeSn alloys implanted with phosphorus ions at 400 °C by spectroscopic ellipsometry from far-infrared to ultraviolet. The dielectric response of heated GeSn implants displays structural and transport properties similar to those of heated Ge implants. The far-infrared dielectric function of as-implanted Ge and GeSn shows the typical free carrier response which can be described by a single Drude oscillator. Bulk Ge-like critical points E1, E1 + Δ1, E0', and E2 are observed in the visible-UV dielectric function of heated Ge and GeSn indicating single crystalline quality of the as-implanted layers. Although the implantation at 400 °C recovers crystallinity in both Ge and GeSn, an annealing step is necessary to enhance the carrier activation.

  11. Single Phosphorus Ion Implantation into Prefabricated Nanometre Cells of Silicon Devices for Quantum Bit Fabrication

    NASA Astrophysics Data System (ADS)

    Yang, Changyi; Jamieson, David N.; Pakes, Chris; Prawer, Steven; Dzurak, Andrew; Stanley, Fay; Spizziri, Paul; Macks, Linda; Gauja, Eric; Clark, Robert G.

    2003-06-01

    In the near future, devices that employ single atoms to store or manipulate information will be constructed. For example, a solid-state quantum computer has been proposed that encodes information in the nuclear spin of shallow arrays of single 31P atoms (quantum bits or qubits) in a matrix of pure silicon. Construction of these devices presents formidable challenges. One strategy is to use single ion implantation, with the energy range of 10 to 20 keV, to load the qubits into prefabricated cells of the device with a period of a few tens of nanometres. We have developed a method of single ion implantation that employs detector electrodes adjacent to the prefabricated qubit cells that can detect on-line single keV ion strikes appropriate for the fabrication of shallow arrays. Our method of the sub-20 keV single ion detection utilizes a pure silicon substrate with a very high resistivity, a thin (5 nm) SiO2 surface layer, biased electrodes applied to the surface and sensitive electronics that can detect the charge transient from single keV ion strikes. We show that our detectors have a near 100% efficiency for keV ions, extremely thin dead layer thickness (˜5 nm) and a wide sensitive region extending laterally from the electrodes (greater than 15 μm) where the nanometre cells can be constructed. We compare the method with the other methods, such as those of measuring the secondary electrons or phonons induced by single ion impacts.

  12. InGaAs/GaAs quantum-dot intermixing using arsenic and phosphorus ion implantation-induced disordering

    NASA Astrophysics Data System (ADS)

    Djie, H. S.; Ooi, B. S.; Aimez, V.

    2006-02-01

    The intermixing of InGaAs/GaAs quantum dot using isoelectric ion implantation followed by rapid thermal annealing is presented. The implantation was carried out at 200 °C with arsenic (As +) and phosphorus (P +) ions, at various doses, where the ions were accelerated at 360 keV with the ion angle tilted by 7°. Compared with impurity-free induced intermixing, the intermixing degree is significantly enhanced by temperature-assisted implantation followed by a rapid thermal annealing below 750 °C. The diffusion transient was observed at a longer annealing duration suggesting the complete intermixing of the implantation-induced damage. A blue shift as large as 126 meV has been observed from the P +-implanted sample, whilst only ˜14 meV has been measured from the Si xN y-capped sample after annealing at 750 °C. The result indicates that a highly selective and low-temperature spatial intermixing, which has a strong potential for photonic integration, could be developed.

  13. [Biodegradable synthetic implant materials : clinical applications and immunological aspects].

    PubMed

    Witte, F; Calliess, T; Windhagen, H

    2008-02-01

    In the last decade biodegradable synthetic implant materials have been established for various clinical applications. Ceramic materials such as calcium phosphate, bioglass and polymers are now routinely used as degradable implants in the clinical practice. Additionally these materials are now also used as coating materials or as microspheres for controlled drug release and belong to a series of examples for applications as scaffolds for tissue engineering. Because immense local concentrations of degradation products are produced during biodegradation, this review deals with the question whether allergic immune reactions, which have been reported for classical metallic and organic implant materials, also play a role in the clinical routine for synthetic biodegradable materials. Furthermore, possible explanatory theories will be developed to clarify the lack of clinical reports on allergy or sensitization to biodegradable synthetic materials.

  14. Molecular phosphorus ion source for semiconductor technologya)

    NASA Astrophysics Data System (ADS)

    Gushenets, V. I.; Bugaev, A. S.; Oks, E. M.; Hershcovitch, A.; Kulevoy, T. V.

    2012-02-01

    This paper presents results on the generation of molecular phosphorus ion beams in a hot filament ion source. Solid red phosphorous is evaporated mainly as tetra-atomic molecules up to a temperature of 800°C. Thus, one of the main conditions for producing maximum P4+ fraction in the beam is to keep the temperature of the phosphorous oven, the steam line and the discharge chamber walls no greater than 800°C. The prior version of our ion source was equipped with a discharge chamber cooling system. The modified source ensured a P4+ ion beam current greater than 30% of the total beam current.

  15. Molecular phosphorus ion source for semiconductor technology

    SciTech Connect

    Gushenets V. I.; Hershcovitch A.; Bugaev, A.S.; Oks, E.M.; Kulevoy, T.V.

    2012-02-15

    This paper presents results on the generation of molecular phosphorus ion beams in a hot filament ion source. Solid red phosphorous is evaporated mainly as tetra-atomic molecules up to a temperature of 800 C. Thus, one of the main conditions for producing maximum P{sub 4}{sup +} fraction in the beam is to keep the temperature of the phosphorous oven, the steam line and the discharge chamber walls no greater than 800 C. The prior version of our ion source was equipped with a discharge chamber cooling system. The modified source ensured a P{sub 4}{sup +} ion beam current greater than 30% of the total beam current.

  16. Molecular phosphorus ion source for semiconductor technology

    SciTech Connect

    Gushenets, V. I.; Bugaev, A. S.; Oks, E. M.; Hershcovitch, A.; Kulevoy, T. V.

    2012-02-15

    This paper presents results on the generation of molecular phosphorus ion beams in a hot filament ion source. Solid red phosphorous is evaporated mainly as tetra-atomic molecules up to a temperature of 800 deg. C. Thus, one of the main conditions for producing maximum P{sub 4}{sup +} fraction in the beam is to keep the temperature of the phosphorous oven, the steam line and the discharge chamber walls no greater than 800 deg. C. The prior version of our ion source was equipped with a discharge chamber cooling system. The modified source ensured a P{sub 4}{sup +} ion beam current greater than 30% of the total beam current.

  17. Predictable synthetic bone grafting procedures for implant reconstruction: part two.

    PubMed

    Ganz, Scott D; Valen, Maurice

    2002-01-01

    When teeth are missing, the surrounding bone and soft tissue is challenged as a result of the natural resorptive process or from traumatic destruction subsequent to extraction. The diminished structural foundation for prosthetic reconstruction with or without implants can therefore be compromised. Recent technological innovations in computer hardware and software have given clinicians the tools to determine 3-dimensional anatomy, quality, and density of bone, which can aid in the diagnosis and treatment planning for reparative or augmentative grafting procedures. Advanced synthetic bioactive resorbable bone graft (SBRG) materials and innovative surgical techniques have made it possible to predictably alter the defective site to create favorable osseous conditions for implant placement. The synthetically derived, resorbable, cluster-like, hydrophilic, particulate, bone-grafting material, having similar mechanical and chemical properties as the host bone, can provide the means to modify existing bone topography by aggressively overpacking the material for ridge preservation, ridge augmentation, or to enhance the bony site and subsequent prosthetic rehabilitation. Since bone does not bridge in empty spaces, the aggressive overfill, commonly referred to as force mineralization, controls excessive bleeding and eliminates voids. Part 1 of this 2-part series presented evidence of safety and effectiveness of the SBRG materials, crystal morphology, chemical properties, and characterization through animal and clinical studies. The osteoconductive cluster particulate assists in the bridging of lost bone anatomy by chemotactic response and resorption concurrent with regeneration of new bone formations. Part 2 demonstrates specific clinical handling characteristics and use of this material to facilitate implant placement and/or prosthetic reconstruction through clinical case applications. Additionally, in a unique clinical presentation, a composite graft mixture consisting of

  18. iNOS Activity Modulates Inflammation, Angiogenesis, and Tissue Fibrosis in Polyether-Polyurethane Synthetic Implants

    PubMed Central

    Cassini-Vieira, Puebla; Araújo, Fernanda Assis; da Costa Dias, Filipi Leles; Russo, Remo Castro; Andrade, Silvia Passos; Teixeira, Mauro Martins; Barcelos, Luciola Silva

    2015-01-01

    There is considerable interest in implantation techniques and scaffolds for tissue engineering and, for safety and biocompatibility reasons, inflammation, angiogenesis, and fibrosis need to be determined. The contribution of inducible nitric oxide synthase (iNOS) in the regulation of the foreign body reaction induced by subcutaneous implantation of a synthetic matrix was never investigated. Here, we examined the role of iNOS in angiogenesis, inflammation, and collagen deposition induced by polyether-polyurethane synthetic implants, using mice with targeted disruption of the iNOS gene (iNOS−/−) and wild-type (WT) mice. The hemoglobin content and number of vessels were decreased in the implants of iNOS−/− mice compared to WT mice 14 days after implantation. VEGF levels were also reduced in the implants of iNOS−/− mice. In contrast, the iNOS−/− implants exhibited an increased neutrophil and macrophage infiltration. However, no alterations were observed in levels of CXCL1 and CCL2, chemokines related to neutrophil and macrophage migration, respectively. Furthermore, the implants of iNOS−/− mice showed boosted collagen deposition. These data suggest that iNOS activity controls inflammation, angiogenesis, and fibrogenesis in polyether-polyurethane synthetic implants and that lack of iNOS expression increases foreign body reaction to implants in mice. PMID:26106257

  19. iNOS Activity Modulates Inflammation, Angiogenesis, and Tissue Fibrosis in Polyether-Polyurethane Synthetic Implants.

    PubMed

    Cassini-Vieira, Puebla; Araújo, Fernanda Assis; da Costa Dias, Filipi Leles; Russo, Remo Castro; Andrade, Silvia Passos; Teixeira, Mauro Martins; Barcelos, Luciola Silva

    2015-01-01

    There is considerable interest in implantation techniques and scaffolds for tissue engineering and, for safety and biocompatibility reasons, inflammation, angiogenesis, and fibrosis need to be determined. The contribution of inducible nitric oxide synthase (iNOS) in the regulation of the foreign body reaction induced by subcutaneous implantation of a synthetic matrix was never investigated. Here, we examined the role of iNOS in angiogenesis, inflammation, and collagen deposition induced by polyether-polyurethane synthetic implants, using mice with targeted disruption of the iNOS gene (iNOS(-/-)) and wild-type (WT) mice. The hemoglobin content and number of vessels were decreased in the implants of iNOS(-/-) mice compared to WT mice 14 days after implantation. VEGF levels were also reduced in the implants of iNOS(-/-) mice. In contrast, the iNOS(-/-) implants exhibited an increased neutrophil and macrophage infiltration. However, no alterations were observed in levels of CXCL1 and CCL2, chemokines related to neutrophil and macrophage migration, respectively. Furthermore, the implants of iNOS(-/-) mice showed boosted collagen deposition. These data suggest that iNOS activity controls inflammation, angiogenesis, and fibrogenesis in polyether-polyurethane synthetic implants and that lack of iNOS expression increases foreign body reaction to implants in mice.

  20. VAGINAL DEGENERATION FOLLOWING IMPLANTATION OF SYNTHETIC MESH WITH INCREASED STIFFNESS

    PubMed Central

    Liang, Rui; Abramowitch, Steven; Knight, Katrina; Palcsey, Stacy; Nolfi, Alexis; Feola, Andrew; Stein, Susan; Moalli, Pamela A.

    2012-01-01

    Objective To compare the impact of the prototype prolapse mesh Gynemesh PS to that of two new generation lower stiffness meshes, UltraPro and SmartMesh, on vaginal morphology and structural composition. Design A mechanistic study employing a non-human primate (NHP) model. Setting Magee-Womens Research Institute at the University of Pittsburgh. Population Parous rhesus macaques, with similar age, weight, parity and POP-Q scores. Methods Following IACUC approval, 50 rhesus macaques were implanted with Gynemesh PS (n=12), UltraPro with its blue line perpendicular to the longitudinal axis of vagina (n=10), UltraPro with its blue line parallel to the longitudinal axis of vagina (n=8) and SmartMesh (n=8) via sacrocolpopexy following hysterectomy. Sham operated animals (n=12) served as controls. Main Outcome Measures The mesh-vagina complex (MVC) was removed after 12 weeks and analyzed for histomorphology, in situ cell apoptosis, total collagen, elastin, glycosaminoglycan content and total collagenase activity. Appropriate statistics and correlation analyses were performed accordingly. Results Relative to sham and the two lower stiffness meshes, Gynemesh PS had the greatest negative impact on vaginal histomorphology and composition. Compared to sham, implantation with Gynemesh PS caused substantial thinning of the smooth muscle layer (1557 ± 499μm vs 866 ± 210 μm, P=0.02), increased apoptosis particularly in the area of the mesh fibers (P=0.01), decreased collagen and elastin content (20% (P=0.03) and 43% (P=0.02), respectively) and increased total collagenase activity (135% (P=0.01)). GAG (glycosaminoglycan), a marker of tissue injury, was the highest with Gynemesh PS compared to sham and other meshes (P=0.01). Conclusion Mesh implantation with the stiffer mesh Gynemesh PS induced a maladaptive remodeling response consistent with vaginal degeneration. PMID:23240802

  1. A synthetic bioactive resorbable graft for predictable implant reconstruction: part one.

    PubMed

    Valen, Maurice; Ganz, Scott D

    2002-01-01

    Animal studies were conducted to evaluate the cell response and chemical potentiality of a synthetic bioactive resorbable graft (SBRG) made of nonceramic cluster particulate of low-temperature HA material. The study evaluated bone-bridging of the SBRG particulates in 1-mm wide implant channels of 5 x 8 mm long roughened titanium interface in 6 dogs and compared results to the same implant channels left empty as controls at 6- and 12-week intervals. Resorption rate capacity and cell response were evaluated with an assessment of the chemical characterization of the synthetic nonceramic material next to the titanium implant interfaces. Results of the animal studies were compared with human histologic biopsies of the SBRG for bone quality, density, and bone growth into defect sites concurrent with resorption time of the graft. One human biopsy consisted of a graft mixture of the SBRG and dense bovine-derived HA, compared under the electron microscope, including histology by H and E staining. Part 1 of this paper presents evidence of the predictability and efficacy of the SBRG osteoconductive, particulate chemical potentiality to aid in the regeneration of lost bone anatomy next to titanium implant interfaces. Recent technological innovations in computer hardware and software have given clinicians the tools to determine 3-dimensional quality and density of bone, including anatomical discrepancies, which can aid in the diagnosis and treatment planning for grafting procedures. When teeth are extracted, the surrounding bone and soft tissue are challenged as a result of the natural resorptive process. The diminished structural foundation for prosthetic reconstruction, with or without implants, can be compromised. A synthetic bioactive resorbable graft material having osteoconductive biochemical and biomechanical qualities similar to the host bone provides the means to improve compromised bone topography for ridge preservation, ridge augmentation, or to enhance the bony site

  2. Influence of argon-implantation on conventional and phototransferred thermoluminescence of synthetic quartz

    NASA Astrophysics Data System (ADS)

    Nsengiyumva, S.; Chithambo, M. L.; Pichon, L.

    2016-03-01

    Conventional and phototransferred thermoluminescence of crystalline synthetic quartz implanted with 70 keV Ar ions at fluences in the range 1 × 1014-5 × 1015 ions/cm2 is reported. The glow curves, recorded at 5°C/s from beta-irradiated samples of similar mass, show a prominent peak between 100°C and 120°C. The thermoluminescence intensity of all implanted samples was greater than that of the unimplanted one. The increase in sensitivity is attributed to a corresponding increase in the concentration of point defects, as a result of the implantation, which act as electron traps or recombination centres. Kinetic analysis carried out using the peak shape, whole glow-peak and curve-fitting methods produced values of the activation energy, frequency factor and order of kinetics that are generally independent of implantation fluence. This result suggests that implantation did not necessarily affect the nature of the electron traps. With respect to phototransferred thermoluminescence, it was observed that it only appeared in the sample implanted at the highest fluence of 5 × 1015 ions/cm2. This may be so because the concentration of deep traps produced as a result of implantation at low fluence is too low to give rise to phototransferred thermoluminescence. The intensity of the phototransferred thermoluminescence goes through a peak with illumination time. We attribute this behaviour to the relative concentration of holes at recombination centres and phototransferred electrons at shallow traps.

  3. Implantable synthetic cytokine converter cells with AND-gate logic treat experimental psoriasis.

    PubMed

    Schukur, Lina; Geering, Barbara; Charpin-El Hamri, Ghislaine; Fussenegger, Martin

    2015-12-16

    Psoriasis is a chronic inflammatory skin disease characterized by a relapsing-remitting disease course and correlated with increased expression of proinflammatory cytokines, such as tumor necrosis factor (TNF) and interleukin 22 (IL22). Psoriasis is hard to treat because of the unpredictable and asymptomatic flare-up, which limits handling of skin lesions to symptomatic treatment. Synthetic biology-based gene circuits are uniquely suited for the treatment of diseases with complex dynamics, such as psoriasis, because they can autonomously couple the detection of disease biomarkers with the production of therapeutic proteins. We designed a mammalian cell synthetic cytokine converter that quantifies psoriasis-associated TNF and IL22 levels using serially linked receptor-based synthetic signaling cascades, processes the levels of these proinflammatory cytokines with AND-gate logic, and triggers the corresponding expression of therapeutic levels of the anti-inflammatory/psoriatic cytokines IL4 and IL10, which have been shown to be immunomodulatory in patients. Implants of microencapsulated cytokine converter transgenic designer cells were insensitive to simulated bacterial and viral infections as well as psoriatic-unrelated inflammation. The designer cells specifically prevented the onset of psoriatic flares, stopped acute psoriasis, improved psoriatic skin lesions and restored normal skin-tissue morphology in mice. The antipsoriatic designer cells were equally responsive to blood samples from psoriasis patients, suggesting that the synthetic cytokine converter captures the clinically relevant cytokine range. Implanted designer cells that dynamically interface with the patient's metabolism by detecting specific disease metabolites or biomarkers, processing their blood levels with synthetic circuits in real time, and coordinating immediate production and systemic delivery of protein therapeutics may advance personalized gene- and cell-based therapies.

  4. Implantable synthetic cytokine converter cells with AND-gate logic treat experimental psoriasis.

    PubMed

    Schukur, Lina; Geering, Barbara; Charpin-El Hamri, Ghislaine; Fussenegger, Martin

    2015-12-16

    Psoriasis is a chronic inflammatory skin disease characterized by a relapsing-remitting disease course and correlated with increased expression of proinflammatory cytokines, such as tumor necrosis factor (TNF) and interleukin 22 (IL22). Psoriasis is hard to treat because of the unpredictable and asymptomatic flare-up, which limits handling of skin lesions to symptomatic treatment. Synthetic biology-based gene circuits are uniquely suited for the treatment of diseases with complex dynamics, such as psoriasis, because they can autonomously couple the detection of disease biomarkers with the production of therapeutic proteins. We designed a mammalian cell synthetic cytokine converter that quantifies psoriasis-associated TNF and IL22 levels using serially linked receptor-based synthetic signaling cascades, processes the levels of these proinflammatory cytokines with AND-gate logic, and triggers the corresponding expression of therapeutic levels of the anti-inflammatory/psoriatic cytokines IL4 and IL10, which have been shown to be immunomodulatory in patients. Implants of microencapsulated cytokine converter transgenic designer cells were insensitive to simulated bacterial and viral infections as well as psoriatic-unrelated inflammation. The designer cells specifically prevented the onset of psoriatic flares, stopped acute psoriasis, improved psoriatic skin lesions and restored normal skin-tissue morphology in mice. The antipsoriatic designer cells were equally responsive to blood samples from psoriasis patients, suggesting that the synthetic cytokine converter captures the clinically relevant cytokine range. Implanted designer cells that dynamically interface with the patient's metabolism by detecting specific disease metabolites or biomarkers, processing their blood levels with synthetic circuits in real time, and coordinating immediate production and systemic delivery of protein therapeutics may advance personalized gene- and cell-based therapies. PMID:26676608

  5. Biological Matrices and Synthetic Meshes Used in Implant-based Breast Reconstruction – a Review of Products Available in Germany

    PubMed Central

    Dieterich, M.; Faridi, A.

    2013-01-01

    While autologous breast reconstruction was considered the procedure of choice for immediate breast reconstruction, there has been a shift towards implant-based breast reconstruction (IBBR) in recent years. The proven safety of silicone breast implants and the development of biological matrices and synthetic meshes have contributed to the growing popularity of this approach. Although these different products are widely used, only limited clinical data are available with regard to breast surgery. The aim of this review was to give an overview of available biological matrices and synthetic meshes and discuss their use in clinical practice. PMID:24771895

  6. Quantification of in vitro wear of a synthetic meniscus implant using gravimetric and micro-CT measurements.

    PubMed

    Elsner, Jonathan J; Shemesh, Maoz; Shefy-Peleg, Adaya; Gabet, Yankel; Zylberberg, Eyal; Linder-Ganz, Eran

    2015-09-01

    A synthetic meniscus implant was recently developed for the treatment of patients with mild to moderate osteoarthritis with knee pain associated with medial joint overload. The implant is distinctively different from most orthopedic implants in its pliable construction, and non-anchored design, which enables implantation through a mini-arthrotomy without disruption to the bone, cartilage, and ligaments. Due to these features, it is important to show that the material and design can withstand knee joint conditions. This study evaluated the long-term performance of this device by simulating loading for a total of 5 million gait cycles (Mc), corresponding to approximately five years of service in-vivo. All five implants remained in good condition and did not dislodge from the joint space during the simulation. Mild abrasion was detected by electron microscopy, but µ-CT scans of the implants confirmed that the damage was confined to the superficial surfaces. The average gravimetric wear rate was 14.5 mg/Mc, whereas volumetric changes in reconstructed µ-CT scans point to an average wear rate of 15.76 mm(3)/Mc (18.8 mg/Mc). Particles isolated from the lubricant had average diameter of 15 µm. The wear performance of this polycarbonate-urethane meniscus implant concept under ISO-14243 loading conditions is encouraging.

  7. Quantification of in vitro wear of a synthetic meniscus implant using gravimetric and micro-CT measurements.

    PubMed

    Elsner, Jonathan J; Shemesh, Maoz; Shefy-Peleg, Adaya; Gabet, Yankel; Zylberberg, Eyal; Linder-Ganz, Eran

    2015-09-01

    A synthetic meniscus implant was recently developed for the treatment of patients with mild to moderate osteoarthritis with knee pain associated with medial joint overload. The implant is distinctively different from most orthopedic implants in its pliable construction, and non-anchored design, which enables implantation through a mini-arthrotomy without disruption to the bone, cartilage, and ligaments. Due to these features, it is important to show that the material and design can withstand knee joint conditions. This study evaluated the long-term performance of this device by simulating loading for a total of 5 million gait cycles (Mc), corresponding to approximately five years of service in-vivo. All five implants remained in good condition and did not dislodge from the joint space during the simulation. Mild abrasion was detected by electron microscopy, but µ-CT scans of the implants confirmed that the damage was confined to the superficial surfaces. The average gravimetric wear rate was 14.5 mg/Mc, whereas volumetric changes in reconstructed µ-CT scans point to an average wear rate of 15.76 mm(3)/Mc (18.8 mg/Mc). Particles isolated from the lubricant had average diameter of 15 µm. The wear performance of this polycarbonate-urethane meniscus implant concept under ISO-14243 loading conditions is encouraging. PMID:26057364

  8. Acromioclavicular joint reconstruction using the LockDown synthetic implant: a study with cadavers.

    PubMed

    Taranu, R; Rushton, P R P; Serrano-Pedraza, I; Holder, L; Wallace, W A; Candal-Couto, J J

    2015-12-01

    Dislocation of the acromioclavicular joint is a relatively common injury and a number of surgical interventions have been described for its treatment. Recently, a synthetic ligament device has become available and been successfully used, however, like other non-native solutions, a compromise must be reached when choosing non-anatomical locations for their placement. This cadaveric study aimed to assess the effect of different clavicular anchorage points for the Lockdown device on the reduction of acromioclavicular joint dislocations, and suggest an optimal location. We also assessed whether further stability is provided using a coracoacromial ligament transfer (a modified Neviaser technique). The acromioclavicular joint was exposed on seven fresh-frozen cadaveric shoulders. The joint was reconstructed using the Lockdown implant using four different clavicular anchorage points and reduction was measured. The coracoacromial ligament was then transferred to the lateral end of the clavicle, and the joint re-assessed. If the Lockdown ligament was secured at the level of the conoid tubercle, the acromioclavicular joint could be reduced anatomically in all cases. If placed medial or 2 cm lateral, the joint was irreducible. If the Lockdown was placed 1 cm lateral to the conoid tubercle, the joint could be reduced with difficulty in four cases. Correct placement of the Lockdown device is crucial to allow anatomical joint reduction. Even when the Lockdown was placed over the conoid tubercle, anterior clavicle displacement remained but this could be controlled using a coracoacromial ligament transfer.

  9. Pretreatment of synthetic vascular grafts with heparin before implantation, a simple technique to reduce the risk of thrombosis.

    PubMed

    Gerrah, Rabin; Sunstrom Pa-C, Rachel E; Hohimer, Alan R

    2015-10-01

    Thrombosis of synthetic grafts commonly used in cardiovascular surgery is a major complication. We examined whether pretreatment of the graft with heparin reduces the risk of early thrombosis. A circuit was assembled to compare two pairs of shunts simultaneously in the same animal. The study shunts were pretreated with heparin. After 2 hours of circulation, clot formation was evaluated by image analysis techniques. The pretreated grafts had fewer blood clots adhered to the surface by direct visual inspection. The image analysis showed 5 vs. 39 clots, 0.01% vs. 1.8% clotted area, and 62 vs. 5630 clot pixel area between the treated and non-treated grafts respectively, p < 0.05. Pretreatment of the synthetic graft with heparin prior to implantation reduces the risk of early clot formation. This simple practice might be helpful to prevent initial thrombosis of the graft and later occlusion.

  10. Effect of Speaking Rate on Recognition of Synthetic and Natural Speech by Normal-Hearing and Cochlear Implant Listeners

    PubMed Central

    Ji, Caili; Galvin, John J.; Xu, Anting; Fu, Qian-Jie

    2012-01-01

    Objective Most studies have evaluated cochlear implant (CI) performance using “clear” speech materials, which are highly intelligible and well-articulated. CI users may encounter much greater variability in speech patterns in the “real-world,” including synthetic speech. In this study, we measured normal-hearing (NH) and CI listeners’ sentence recognition with multiple talkers and speaking rates, and with naturally produced and synthetic speech. Design NH and CI subjects were asked to recognize naturally produced or synthetic sentences, presented at a slow, normal, or fast speaking rate. Natural speech was produced by one male and one female talker; synthetic speech was generated to simulate a male and female talker. For natural speech, the speaking rate was time-scaled while preserving voice pitch and formant frequency information. For synthetic speech, the speaking rate was adjusted within the speech synthesis engine. NH subjects were tested while listening to unprocessed speech or to an 8-channel acoustic CI simulation. CI subjects were tested while listening with their clinical processors and the recommended microphone sensitivity and volume settings. Results The NH group performed significantly better than the CI simulation group, and the CI simulation group performed significantly better than the CI group. For all subject groups, sentence recognition was significantly better with natural than with synthetic speech. The performance deficit with synthetic speech was relatively small for NH subjects listening to unprocessed speech. However, the performance deficit with synthetic speech was much greater for CI subjects and for CI simulation subjects. There was significant effect of talker gender, with slightly better performance with the female talker for CI subjects and slightly better performance with the male talker for the CI simulations. For all subject groups, sentence recognition was significantly poorer only at the fast rate. CI performance was

  11. High protracted (99m)Tc-HDP uptake in synthetic bone implants - a potentially misleading incidental finding on bone scintigraphy.

    PubMed

    Tabouret-Viaud, Claire; Mainta, Ismini; Boudabbous, Sana; Amzalag, Gaël; Ratib, Osman; Rager, Olivier; Paycha, Frédéric

    2014-12-01

    We report the case of a 56-year-old male with bilateral total knee prostheses suffering from bilateral knee pain mainly on the right side and referred for bone scintigraphy. The medical history of the patient revealed an opening wedge high tibial osteotomy performed nine years earlier, with insertion of two blocks of ceramic made of hydroxyapatite and tricalcium phosphate in a wedge configuration as synthetic bone substitutes. The porous structure of these implants is analogous to the architecture of cancellous bone and permits fibrovascular and bone ingrowth, promoting the healing process. Planar scintigraphy and SPECT/CT showed an intense uptake within those implants in the early phase as well as in the late phase of the bone scan. It also showed bilateral patellofemoral arthritis. A (99m)Tc-labeled antigranulocyte antibody scintigraphy was negative for infection or inflammation. Bilateral patellar resurfacing led to complete symptom regression, confirmed at 10 months follow-up. To the best of our knowledge, this scintigraphic pattern with such a high tracer uptake reflecting bone substitute osteointegration has not yet been published. This should be considered in patients with such bone replacement materials that are increasingly used, in order to avoid false diagnosis of inflammation or infection.

  12. Effects of CO2, thulium, and erbium lasers on middle ear synthetic implants

    NASA Astrophysics Data System (ADS)

    Bottrill, Ian; Valtonen, Hannu J.; Poe, Dennis S.

    1995-05-01

    10.6 micrometers CO2, 2.01 micrometers Thulium:YAG (Tm:YAG) and 2.94 micrometers Erbium:YAG (Er:YAG) are currently being used or investigated for potential applications in otologic surgery. In addition to biologic tissue there are numerous synthetic materials (Gelfoam, Silastic, C-Flex, Silicone and Teflon), mineral components (Hydroxylapatite) and metals (stainless steel) that may be encountered during surgery. Their behavior in response to laser irradiation is, for the most part, unknown. We investigated the effects of these lasers, operated at clinically relevant parameters on these materials. We looked for signs of melting, perforation, charring, smoke formation and ignition. The results show that wet Gelfoam proved to be a partially effective barrier to all lasers. Silastic transmitted the energy of the Tm and Er:YAG with minimal damage, but charred, ignited or exploded with the CO2 depending on the energy applied. All lasers melted C-Flex at higher energies. On Silicon, CO2 produced flames, char and melting; the other lasers produced a tiny spark and less melting. Teflon charred and perforated when exposed to any laser, but only Tm:YAG produced a spark. All lasers at moderate and high energies shattered hydroxylapatite. Stainless steel was not affected by CO2, but was perforated by Tm:YAG and Er:YAG. The results suggest that none of the tested lasers are safe for all currently used prosthetic materials and therefore they should be used with caution.

  13. Development of an implantable synthetic membrane for the treatment of preterm premature rupture of fetal membranes.

    PubMed

    Roman, Sabiniano; Bullock, Anthony J; Anumba, Dilly O; MacNeil, Sheila

    2016-02-01

    Preterm premature rupture of fetal membranes is a very common condition leading to premature labour of a non viable fetus. Significant morbidities may occur when preterm premature rupture of fetal membranes management is attempted to prolong the pregnancy for fetal maturation. Reducing the rate of loss of amniotic fluid and providing a barrier to bacterial entry may allow the pregnancy to continue to term, avoiding complications. Our aim is to develop a synthetic biocompatible membrane to form a distensible barrier for cervical closure which acts to reduce fluid loss and provide a surface for epithelial ingrowth to help repair the damaged membranes. Therefore, a bilayer membrane was developed using an electrospinning technique of combining two FDA-approved polymers, poly-L-lactic acid (PLA) and polyurethane (Z3) polymer. This was compared to a plain electrospun Z3 membrane. The physical and mechanical properties were assessed using scanning electron microscope images and a BOSE tensiometer, respectively, and compared to native fetal membranes. The performance of the membranes in preventing fluid loss was assessed by measuring their ability to support a column of water. Finally the ability of the membranes to support cell ingrowth was assessed by culturing adipose-derived stem cells on the membranes for two weeks and assessing metabolic activity after 7 and 14 days. The physical properties of the bilayer were similar to that of the native fetal membranes and it was resistant to fluid penetration. This bilayer membrane presented mechanical properties close to those for fetal membranes and showed elastic distention, which may be crucial for progress of the pregnancy. The membrane was also able to retain surgical sutures. In addition, it also supported the attachment and growth of adipose-derived stem cells for two weeks. In conclusion, this membrane may prove a useful approach in the treatment of preterm premature rupture of fetal membranes and now merits further

  14. Regulation of Cellular Response Pattern to Phosphorus Ion is a New Target for the Design of Tissue-Engineered Blood Vessel.

    PubMed

    Chen, Wen; Wang, Fangjuan; Zeng, Wen; Sun, Jun; Li, Li; Yang, Mingcan; Sun, Jiansen; Wu, Yangxiao; Zhao, Xiaohui; Zhu, Chuhong

    2015-05-01

    Regulation of cellular response pattern to phosphorus ion (PI) is a new target for the design of tissue-engineered materials. Changing cellular response pattern to high PI can maintain monocyte/macrophage survival in TEBV and the signal of increasing PI can be converted by klotho to the adenosine signals through the regulation of energy metabolism in monocytes/macrophages. PMID:25694105

  15. Effect of Blood Component Coatings of Enosseal Implants on Proliferation and Synthetic Activity of Human Osteoblasts and Cytokine Production of Peripheral Blood Mononuclear Cells

    PubMed Central

    Hulejova, Hana; Bartova, Jirina; Riedel, Tomas; Pesakova, Vlasta

    2016-01-01

    The study monitored in vitro early response of connective tissue cells and immunocompetent cells to enosseal implant materials coated by different blood components (serum, activated plasma, and plasma/platelets) to evaluate human osteoblast proliferation and synthetic activity and inflammatory response presented as a cytokine profile of peripheral blood mononuclear cells (PBMCs) under conditions imitating the situation upon implantation. The cells were cultivated on coated Ti-plasma-sprayed (Ti-PS), Ti-etched (Ti-Etch), Ti-hydroxyapatite (Ti-HA), and ZrO2 surfaces. The plasma/platelets coating supported osteoblast proliferation only on osteoconductive Ti-HA and Ti-Etch whereas activated plasma enhanced proliferation on all surfaces. Differentiation (BAP) and IL-8 production remained unchanged or decreased irrespective of the coating and surface; only the serum and plasma/platelets-coated ZrO2 exhibited higher BAP and IL-8 expression. RANKL production increased on serum and activated plasma coatings. PBMCs produced especially cytokines playing role in inflammatory phase of wound healing, that is, IL-6, GRO-α, GRO, ENA-78, IL-8, GM-CSF, EGF, and MCP-1. Cytokine profiles were comparable for all tested surfaces; only ENA-78, IL-8, GM-CSF, and MCP-1 expression depended on materials and coatings. The activated plasma coating led to uniformed surfaces and represented a favorable treatment especially for bioinert Ti-PS and ZrO2 whereas all coatings had no distinctive effect on bioactive Ti-HA and Ti-Etch.

  16. Osseointegration of dental implants in 3D-printed synthetic onlay grafts customized according to bone metabolic activity in recipient site.

    PubMed

    Tamimi, Faleh; Torres, Jesus; Al-Abedalla, Khadijeh; Lopez-Cabarcos, Enrique; Alkhraisat, Mohammad H; Bassett, David C; Gbureck, Uwe; Barralet, Jake E

    2014-07-01

    Onlay grafts made of monolithic microporous monetite bioresorbable bioceramics have the capacity to conduct bone augmentation. However, there is heterogeneity in the graft behaviour in vivo that seems to correlate with the host anatomy. In this study, we sought to investigate the metabolic activity of the regenerated bone in monolithic monetite onlays by using positron emission tomography-computed tomography (PET-CT) in rats. This information was used to optimize the design of monetite onlays with different macroporous architecture that were then fabricated using a 3D-printing technique. In vivo, bone augmentation was attempted with these customized onlays in rabbits. PET-CT findings demonstrated that bone metabolism in the calvarial bone showed higher activity in the inferior and lateral areas of the onlays. Histological observations revealed higher bone volume (up to 47%), less heterogeneity and more implant osseointegration (up to 38%) in the augmented bone with the customized monetite onlays. Our results demonstrated for the first time that it is possible to achieve osseointegration of dental implants in bone augmented with 3D-printed synthetic onlays. It was also observed that designing the macropore geometry according to the bone metabolic activity was a key parameter in increasing the volume of bone augmented within monetite onlays.

  17. Estrogens and synthetic androgens in manure slurry from trenbolone acetate/estradiol implanted cattle and in waste-receiving lagoons used for irrigation.

    PubMed

    Khan, Bushra; Lee, Linda S

    2012-11-01

    The increasing size of concentrated animal feeding operations has led to a concomitant increase in the land-application of manure, which has spawned research on the concentrations and environmental risk assessment of natural and synthetic hormones in animal manures. 17β-Trenbolone acetate (TBA) is widely used in the United States for improving daily gains in beef cattle and is often administered in combination with 17β-estradiol (17β-E2). Trenbolone (TB) and E2 isomers and their metabolites were quantified in manure collection pits and lagoon effluent from beef cattle implanted with the commercial anabolic preparation Ravoler-S (containing 140 mg 17β-trenbolone acetate and 28 mg 17β-E2). Manure pit and lagoon effluent samples were collected weekly for 9 weeks post implanting and analyzed using reverse-phase liquid chromatography tandem mass spectrometry. 17α-TB was the most abundant androgen with the highest concentration observed 2 weeks post implant. 17β-TB and trendione peaked at the end of week 2 and 4, respectively. For the estrogens, the highest concentrations for estrone (E1), estriol (E3), and 17α-E2 were observed after week 4, 6, and 8, respectively. 17β-E2 concentrations were the lowest of the estrogens and erratic over time. In lagoon water, which is used for irrigation, 17α-TB and E1 had the highest detected hormone concentrations (1.53 and 1.72 μg L(-1), respectively). Assuming a 1-2 order dilution during transport to surface water, these hormone levels could lead to concentrations in receiving waters that exceed some of the lowest observable effect levels (LOELs) reported for hormones (e.g., 0.01-0.03 μg L(-1)).

  18. Estrogens and synthetic androgens in manure slurry from trenbolone acetate/estradiol implanted cattle and in waste-receiving lagoons used for irrigation.

    PubMed

    Khan, Bushra; Lee, Linda S

    2012-11-01

    The increasing size of concentrated animal feeding operations has led to a concomitant increase in the land-application of manure, which has spawned research on the concentrations and environmental risk assessment of natural and synthetic hormones in animal manures. 17β-Trenbolone acetate (TBA) is widely used in the United States for improving daily gains in beef cattle and is often administered in combination with 17β-estradiol (17β-E2). Trenbolone (TB) and E2 isomers and their metabolites were quantified in manure collection pits and lagoon effluent from beef cattle implanted with the commercial anabolic preparation Ravoler-S (containing 140 mg 17β-trenbolone acetate and 28 mg 17β-E2). Manure pit and lagoon effluent samples were collected weekly for 9 weeks post implanting and analyzed using reverse-phase liquid chromatography tandem mass spectrometry. 17α-TB was the most abundant androgen with the highest concentration observed 2 weeks post implant. 17β-TB and trendione peaked at the end of week 2 and 4, respectively. For the estrogens, the highest concentrations for estrone (E1), estriol (E3), and 17α-E2 were observed after week 4, 6, and 8, respectively. 17β-E2 concentrations were the lowest of the estrogens and erratic over time. In lagoon water, which is used for irrigation, 17α-TB and E1 had the highest detected hormone concentrations (1.53 and 1.72 μg L(-1), respectively). Assuming a 1-2 order dilution during transport to surface water, these hormone levels could lead to concentrations in receiving waters that exceed some of the lowest observable effect levels (LOELs) reported for hormones (e.g., 0.01-0.03 μg L(-1)). PMID:22795306

  19. Non-mass-analyzed ion implantation from a solid phosphorus source

    NASA Technical Reports Server (NTRS)

    Spitzer, M. B.; Bunker, S. N.

    1982-01-01

    A phosphorus ion beam, extracted from a Freeman ion source charged with elemental phosphorus, has been investigated for use in solar cell fabrication. Mass spectroscopy of the beam indicates the absence of both minority-carrier lifetime degrading impurities and hydrogen. The ion beam, without mass analysis, was used for ion implantation of solar cells, and performance for all cells was found to be equivalent to mass-analyzed controls.

  20. Effect of Blood Component Coatings of Enosseal Implants on Proliferation and Synthetic Activity of Human Osteoblasts and Cytokine Production of Peripheral Blood Mononuclear Cells.

    PubMed

    Himmlova, Lucie; Kubies, Dana; Hulejova, Hana; Bartova, Jirina; Riedel, Tomas; Stikarova, Jana; Suttnar, Jiri; Pesakova, Vlasta

    2016-01-01

    The study monitored in vitro early response of connective tissue cells and immunocompetent cells to enosseal implant materials coated by different blood components (serum, activated plasma, and plasma/platelets) to evaluate human osteoblast proliferation and synthetic activity and inflammatory response presented as a cytokine profile of peripheral blood mononuclear cells (PBMCs) under conditions imitating the situation upon implantation. The cells were cultivated on coated Ti-plasma-sprayed (Ti-PS), Ti-etched (Ti-Etch), Ti-hydroxyapatite (Ti-HA), and ZrO2 surfaces. The plasma/platelets coating supported osteoblast proliferation only on osteoconductive Ti-HA and Ti-Etch whereas activated plasma enhanced proliferation on all surfaces. Differentiation (BAP) and IL-8 production remained unchanged or decreased irrespective of the coating and surface; only the serum and plasma/platelets-coated ZrO2 exhibited higher BAP and IL-8 expression. RANKL production increased on serum and activated plasma coatings. PBMCs produced especially cytokines playing role in inflammatory phase of wound healing, that is, IL-6, GRO-α, GRO, ENA-78, IL-8, GM-CSF, EGF, and MCP-1. Cytokine profiles were comparable for all tested surfaces; only ENA-78, IL-8, GM-CSF, and MCP-1 expression depended on materials and coatings. The activated plasma coating led to uniformed surfaces and represented a favorable treatment especially for bioinert Ti-PS and ZrO2 whereas all coatings had no distinctive effect on bioactive Ti-HA and Ti-Etch. PMID:27651560

  1. Effect of Blood Component Coatings of Enosseal Implants on Proliferation and Synthetic Activity of Human Osteoblasts and Cytokine Production of Peripheral Blood Mononuclear Cells

    PubMed Central

    Hulejova, Hana; Bartova, Jirina; Riedel, Tomas; Pesakova, Vlasta

    2016-01-01

    The study monitored in vitro early response of connective tissue cells and immunocompetent cells to enosseal implant materials coated by different blood components (serum, activated plasma, and plasma/platelets) to evaluate human osteoblast proliferation and synthetic activity and inflammatory response presented as a cytokine profile of peripheral blood mononuclear cells (PBMCs) under conditions imitating the situation upon implantation. The cells were cultivated on coated Ti-plasma-sprayed (Ti-PS), Ti-etched (Ti-Etch), Ti-hydroxyapatite (Ti-HA), and ZrO2 surfaces. The plasma/platelets coating supported osteoblast proliferation only on osteoconductive Ti-HA and Ti-Etch whereas activated plasma enhanced proliferation on all surfaces. Differentiation (BAP) and IL-8 production remained unchanged or decreased irrespective of the coating and surface; only the serum and plasma/platelets-coated ZrO2 exhibited higher BAP and IL-8 expression. RANKL production increased on serum and activated plasma coatings. PBMCs produced especially cytokines playing role in inflammatory phase of wound healing, that is, IL-6, GRO-α, GRO, ENA-78, IL-8, GM-CSF, EGF, and MCP-1. Cytokine profiles were comparable for all tested surfaces; only ENA-78, IL-8, GM-CSF, and MCP-1 expression depended on materials and coatings. The activated plasma coating led to uniformed surfaces and represented a favorable treatment especially for bioinert Ti-PS and ZrO2 whereas all coatings had no distinctive effect on bioactive Ti-HA and Ti-Etch. PMID:27651560

  2. Nickel ohmic contacts of high-concentration P-implanted 4H-SiC

    NASA Astrophysics Data System (ADS)

    Chunjuan, Liu; Su, Liu; Jingjing, Feng; Rong, Wu

    2012-03-01

    Different-dose phosphorus ion implantation into 4H-SiC followed by high-temperature annealing was investigated. AlN/BN and graphite post-implantation annealing for ion-implanted SiC at 1650 °C for 30 min was conducted to electrically activate the implanted P+ ions. Ni contacts to the P+-implanted 4H-SiC layers were examined by transmission line model and Hall measurements fabricated on P-implanted (0001). The results indicated that a high-quality ohmic contact and specific contact resistivity of 1.30 × 10-6 Ω · cm2 was obtained for the P+-implanted 4H-SiC layers. The ρC values of the Ni-based implanted layers decreased with increasing P doping concentrations, and a weaker temperature dependence was observed for different samples in the 200-500 K temperature range.

  3. Evaluation of the healing process after implantation of synthetic material called Tegmentum consisting of polyester mesh covered with polyurethane in rat peritoneum.

    PubMed

    Fila, M; Banach, M; Zwoliński, R

    2000-01-01

    Polyester meshes are one of the synthetic prosthetic materials widely applied for the reconstruction of abdominal layers in child and neonatal surgery, cardiosurgery or vascular surgery. Because of the lack or insufficiency of the own, natural material multiple researches are performed in order to find the best material able to replace natural tissue. The most suitable prosthesis ought to be: sterile, non-toxic, soft, flexible, elastic, not very stretchy, durable, easy to operate (cutting, suturing); to create desired shape required while reconstracting, totally resistant to contagion, without any complication after being implanted. Since early seventies many scientists following above requirements have carried out researches to create the most similar prosthesis morphologically and functionally to human tissue but still there is no such an ideal material on the market. Polyester with its derivatives is one of the most commonly applied synthetic substances in surgery. The type of biomaterial highly depends on its purpose e.g.: for vascular prosthesis materials that are resorptive in organism and support tightness (gelatine, albumin, collagen); while for temporal replacement abdominal layers with prosthesis the most suitable is impervious to systemic fluids bacteria etc material, that prevents penetrating the surface of prosthesis by surrounding tissues, adhesions with intestinum or other organs. Tegmentum is a material that posses these features. This is a polyester mesh covered with polyurethane on one side produced by Tricomed S.A. (Łódź). Tegmentum has already been applied to neonates with congenital eventration in Child and Neonatal Ward in the "Szpital Pomnik Matki Polki" hospital in Łódź. PMID:11288603

  4. Investigation of the performance of articular cartilage and synthetic biomaterials in multi-directional sliding motion as in orthopedic implants

    NASA Astrophysics Data System (ADS)

    Schwartz, Christian John

    The performance of several synthetic biomaterials and bovine articular cartilage were investigated in terms of their suitability for use as articulating surfaces in artificial joints. The Dual-Axis Wear Simulator (DAWS), a wear testing machine that simulates conditions in a synovial joint, was designed and fabricated to enable investigators to measure the wear of such materials in multi-directional sliding while immersed in a bovine serum lubricant solution. This machine was used initially to determine the wear mechanisms and wear amounts of ultra-high molecular weight polyethylene (UHMWPE), polytetrafluoroethylene (PTFE), polyoxymethylene (POM), and the compliant elastomer Pellethane(TM) 2363-80A. It was found that the compliant material produced lower wear. Dynamic mechanical analysis was used to determine that bovine articular cartilage had a very significant amount of viscoelasticity to support static loads and damp impact loads. Furthermore, the use of a compliant counterface led to lower wear in the cartilage as compared to a rigid counterface. Pt-Zr quasicrystals were used as fillers in UHMWPE, and the wear, stiffness, and impact toughness of the filled polymer were shown to be comparable or better than those of UHMWPE that had been irradiation crosslinked. Crosslinked UHMWPE was investigated for its susceptibility to oxidative degradation and increased wear. It was found that thermal stabilization of the polymer could be eliminated if a mild amount crosslinking was used. Furthermore, there was no degradation in wear resistance of mildly crosslinked and non-stabilized UHMWPE even after accelerated aging. Based on the results of this work and lessons learned about compliance and wear resistance, blends were produced by using surface-activated UHMWPE particles as fillers in elastomeric PUR. The blends showed better wear resistance than UHMWPE, as well as increased stiffness and damping over PUR. The results of this work indicated that there is great potential

  5. Prospects of implant with locking plate in fixation of subtrochanteric fracture: experimental demonstration of its potential benefits on synthetic femur model with supportive hierarchical nonlinear hyperelastic finite element analysis

    PubMed Central

    2012-01-01

    Background Effective fixation of fracture requires careful selection of a suitable implant to provide stability and durability. Implant with a feature of locking plate (LP) has been used widely for treating distal fractures in femur because of its favourable clinical outcome, but its potential in fixing proximal fractures in the subtrochancteric region has yet to be explored. Therefore, this comparative study was undertaken to demonstrate the merits of the LP implant in treating the subtrochancteric fracture by comparing its performance limits against those obtained with the more traditional implants; angle blade plate (ABP) and dynamic condylar screw plate (DCSP). Materials and Methods Nine standard composite femurs were acquired, divided into three groups and fixed with LP (n = 3), ABP (n = 3) and DCSP (n = 3). The fracture was modeled by a 20 mm gap created at the subtrochanteric region to experimentally study the biomechanical response of each implant under both static and dynamic axial loading paradigms. To confirm the experimental findings and to understand the critical interactions at the boundaries, the synthetic femur/implant systems were numerically analyzed by constructing hierarchical finite element models with nonlinear hyperelastic properties. The predictions from the analyses were then compared against the experimental measurements to demonstrate the validity of each numeric model, and to characterize the internal load distribution in the femur and load bearing properties of each implant. Results The average measurements indicated that the constructs with ABP, DCPS and LP respectively had overall stiffness values of 70.9, 110.2 and 131.4 N/mm, and exhibited reversible deformations of 12.4, 4.9 and 4.1 mm when the applied dynamic load was 400 N and plastic deformations of 11.3, 2.4 and 1.4 mm when the load was 1000 N. The corresponding peak cyclic loads to failure were 1100, 1167 and 1600 N. The errors between the

  6. Raman scattering probe of ion-implanted and pulse laser annealed GaAs

    NASA Astrophysics Data System (ADS)

    Verma, Prabhat; Jain, K. P.; Abbi, S. C.

    1996-04-01

    We report Raman scattering studies of phosphorus-ion-implanted and subsequently pulse laser annealed (PLA) GaAs. The threshold value of implantation fluence for the disappearance of one-phonon modes in the Raman spectrum of ion-implanted GaAs sample is found to be greater than that for the two-phonon modes by an order of magnitude. The phonon correlation length decreases with increasing disorder. The lattice reconstruction process during PLA creates microcrystallites for incomplete annealing, whose sizes can be given by the phonon correlation lengths, and are found to increase with the annealing power density. The intensity ratio of the Raman spectra corresponding to the allowed longitudinal-optical (LO)-phonon mode to the forbidden transverse-optical (TO)-phonon mode, ILO/ITO, is used as a quantitative measure of crystallinity in the implantation and PLA processes. The threshold annealing power density is estimated to be 20 MW/cm2 for 70 keV phosphorus-ion-implanted GaAs at a fluence of 5×1015 ions/cm2. The localized vibrational mode of phosphorus is observed in PLA samples for fluences above 1×1015 ions/cm2.

  7. Thin hydroxyapatite surface layers on titanium produced by ion implantation

    NASA Astrophysics Data System (ADS)

    Baumann, H.; Bethge, K.; Bilger, G.; Jones, D.; Symietz, I.

    2002-11-01

    In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (α,α) backscattering and the resonant nuclear reaction 1H( 15N,αγ) 12C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of marrow bone cells on the implanted sample surface with that of titanium.

  8. Effects of positive ion implantation into antireflection coating of silicon solar cells

    NASA Technical Reports Server (NTRS)

    Middleton, A. E.; Harpster, J. W.; Collis, W. J.; Kim, C. K.

    1971-01-01

    The state of technological development of Si solar cells for highest obtained efficiency and radiation resistance is summarized. The various theoretical analyses of Si solar cells are reviewed. It is shown that factors controlling blue response are carrier diffusion length, surface recombination, impurity concentration profile in surface region, high level of surface impurity concentration (degeneracy), reflection coefficient of oxide, and absorption coefficient of Si. The theory of ion implantation of charge into the oxide antireflection coating is developed and side effects are discussed. The experimental investigations were directed at determining whether the blue response of Si solar cells could be improved by phosphorus ion charges introduced into the oxide antireflection coating.

  9. Probing the carrier concentration profiles in phosphorus-implanted germanium using infrared spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    D'Costa, Vijay Richard; Yeo, Yee-Chia

    2015-02-01

    Spectroscopic ellipsometry with photon energy in the 0.045-0.65 eV range was used to investigate germanium samples implanted with 30 keV phosphorus ions and annealed at 700 °C. The infrared response of implanted layers is dominated by free carrier absorption which is modeled using a Drude oscillator. The carrier concentration profiles were modeled using an error function, and compared with those obtained by electrochemical capacitance-voltage profiling and secondary ion mass spectrometry. In the flat region of the carrier concentration profile, average carrier concentration and mobility of 1.40 × 1019 cm-3 and 336 cm2V-1s-1, respectively, were obtained. A phosphorus diffusivity of ˜1.2 × 10-13 cm2/s was obtained. The mobility versus carrier concentration relationships obtained for the implanted samples are close to the empirical relationship for bulk Ge.

  10. Positron annihilation studies of fluorine-vacancy complexes in phosphorus- and fluorine-implanted germanium

    NASA Astrophysics Data System (ADS)

    Edwardson, C. J.; Coleman, P. G.; El Mubarek, H. A. W.

    2014-03-01

    The formation of FnV2 complexes, with n = 5 ± 1, near the end-of-range damage region in germanium implanted with 30 keV phosphorus and 40 keV fluorine ions, after annealing to 400 °C, has been observed using variable-energy positron annihilation spectroscopy in conjunction with secondary ion mass spectrometry. Phosphorus ions were implanted at 6 × 1013 and 1015, F at 1015 cm-2. Complexes—at lower concentrations—have also been observed at shallower depths in samples implanted with P at 1015 cm-2. The complexes break up and their components diffuse away at 450 and 500 °C for the higher and lower P dose samples, respectively.

  11. n{sup +}/p diodes by ion implantation: Dopant, extended defects, and impurity concerns

    SciTech Connect

    Xu, M.; Venables, D.; Christensen, K.N.; Maher, D.M.

    1995-08-01

    The present study is concerned with the formation of defect structures resulting from phosphorus ion implantation into p-type, <100> silicon and with the rearrangement as well as removal of defect structures following high temperature annealing. The problematic interaction of background impurities with extended defects also is included in this study, as are the non-illuminated and illuminated electrical characteristics of n+/p diodes that are fabricated using ion implantation. Wafers and diodes that are fabricated using a phosphorus planar diffusion technique are run in parallel and serve as the controls. In this contribution, preliminary results for the cases of a 50 keV implant followed by an anneal at 900{degrees}C/30 min and a diffusion at 825{degrees}C/60 min are summarized.

  12. Nerve regeneration and elastin formation within poly(glycerol sebacate)-based synthetic arterial grafts one-year post-implantation in a rat model

    PubMed Central

    Allen, Robert A.; Wu, Wei; Yao, Mingyi; Dutta, Debaditya; Duan, Xinjie; Bachman, Timothy N.; Champion, Hunter C.; Stolz, Donna B.; Robertson, Anne M.; Kim, Kang; Isenberg, Jeffrey S.; Wang, Yadong

    2013-01-01

    The objective of this study was to evaluate the long term performance of cell-free vascular grafts made from a fast-degrading elastic polymer. We fabricated small arterial grafts from microporous tubes of poly(glycerol sebacate) (PGS) reinforced with polycaprolactone (PCL) nanofibers on the outer surface. Grafts were interpositioned in rat abdominal aortas and characterized at 1 year post-implant. Grafts remodeled into “neoarteries” (regenerated arteries) with similar gross appearance to native rat aortas. Neoarteries mimic arterial tissue architecture with a confluent endothelium and media and adventita-like layers. Patent vessels (80%) showed no significant stenosis, dilation, or calcification. Neoarteries contain nerves and have the same amount of mature elastin as native arteries. Despite some differences in matrix organization, regenerated arteries had similar dynamic mechanical compliance to native arteries in vivo. Neoarteries responded to vasomotor agents, albeit with different magnitude than native aortas. These data suggest that an elastic vascular graft that resorbs quickly has potential to improve the performance of vascular grafts used in small arteries. This design may also promote constructive remodeling in other soft tissues. PMID:24119457

  13. Biomechanical Comparison of Pedicle Screw Augmented with Different Volumes of Polymethylmethacrylate in Osteoporotic and Severely Osteoporotic Synthetic Bone Blocks in Primary Implantation: An Experimental Study

    PubMed Central

    Liu, Da; Zhang, Xiao-jun; Liao, Dong-fa; Zhou, Jiang-jun; Li, Zhi-qiang; Zhang, Bo; Wang, Cai-ru; Lei, Wei; Kang, Xia; Zheng, Wei

    2016-01-01

    This study was designed to compare screw stabilities augmented with different volumes of PMMA and analyze relationship between screw stability and volume of PMMA and optimum volume of PMMA in different bone condition. Osteoporotic and severely osteoporotic synthetic bone blocks were divided into groups A0-A5 and B0-B5, respectively. Different volumes of PMMA were injected in groups A0 to A5 and B0 to B5. Axial pullout tests were performed and Fmax was measured. Fmax in groups A1-A5 were all significantly higher than group A0. Except between groups A1 and A2, A3 and A4, and A4 and A5, there were significant differences on Fmax between any other two groups. Fmax in groups B1-B5 were all significantly higher than group B0. Except between groups B1 and B2, B2 and B3, and B4 and B5, there were significant differences on Fmax between any other two groups. There was significantly positive correlation between Fmax and volume of PMMA in osteoporotic and severely osteoporotic blocks. PMMA can significantly enhance pedicle screw stability in osteoporosis and severe osteoporosis. There were positive correlations between screw stability and volume of PMMA. In this study, injection of 3 mL and 4 mL PMMA was preferred in osteoporotic and severely osteoporotic blocks, respectively. PMID:26885525

  14. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  15. [Application of elemental microanalysis for estimation of osteoinduction and osteoconduction of hydroxyapatite bone implants].

    PubMed

    Dawidowicz, Aleksander; Pielka, Stanisław; Paluch, Danuta; Kuryszko, Jan; Staniszewska-Kuś, Jolanta; Solski, Leszek

    2005-01-01

    Hydroxyapatite (HAp) ceramics based on calcium phosphates, chemical compounds being natural constructive element of bones is now regarded to be one of better implantation materials in osseous surgery and stomatology. HAp is poorly soluble and slowly resorbing in tissues material. Easiness of connecting of hydroxyapatite ceramics with other materials creates possibilities to produce new composites of chemical compounds containing calcium and easier resorbing. An important and till now not fully known problem is influence of hydrodroxyapatite grafts on the processes leading to production of calcium and phosphorus ions responsive for mineralization of bone tissue around the graft. Proliferation of osteoblasts and rate of osseous trabeculas production depends, among others, concentration of calcium and phosphorus ions. The main target of this study was the comparative analysis of the bone mineralisation rate after implantation of hydroxyapatite (HAp) and composites hydroxyapatite + beta tricalcium phosphate (HAp + TCP) and hydroxyapatite + calcium hydrosulfate (HAp + gypsum), on the basis of elemental microanalysis. Implantation studies were carried out on 24 rabbits. Sections were carried out 5, 9, 11 and 14 weeks after implantation of the tested materials. The carried out punctual analysis of the occurring elements and their topographic location (mapping) in bones after implantation showed essential differences among the tested grafts. Those differences were most significant after 5 and 14 weeks and depended on the rate of the tested materials resorption. On the basis of conducted macroscopic evaluation and scanning microscope assessment we can stated that the composite of HAp+TCP showed the best osteocunductive properties, while the best osteoinductive influence was shown by the composite HAp + gypsum.

  16. High-Dose Phosphorus-Implanted 4H-SiC: Microwave and Conventional Post-Implantation Annealing at Temperatures ≥1700°C

    NASA Astrophysics Data System (ADS)

    Nipoti, R.; Nath, A.; Qadri, S. B.; Tian, Y.-L.; Albonetti, C.; Carnera, A.; Rao, Mulpuri V.

    2012-03-01

    Semi-insulating 4H-SiC ⟨0001⟩ wafers have been phosphorus ion implanted at 500°C to obtain phosphorus box depth profiles with dopant concentration from 5 × 1019 cm-3 to 8 × 1020 cm-3. These samples have been annealed by microwave and conventional inductively heated systems in the temperature range 1700°C to 2050°C. Resistivity, Hall electron density, and Hall mobility of the phosphorus-implanted and annealed 4H-SiC layers have been measured in the temperature range from room temperature to 450°C. The high-resolution x-ray diffraction and rocking curve of both virgin and processed 4H-SiC samples have been analyzed to obtain the sample crystal quality up to about 3 μm depth from the wafer surface. For both increasing implanted phosphorus concentration and increasing post-implantation annealing temperature the implanted material resistivity decreases to an asymptotic value of about 1.5 × 10-3 Ω cm. Increasing the implanted phosphorus concentration and post-implantation annealing temperature beyond 4 × 1020 cm-3 and 2000°C, respectively, does not bring any apparent benefit with respect to the minimum obtainable resistivity. Sheet resistance and sheet electron density increase with increasing measurement temperature. Electron density saturates at 1.5 × 1020 cm-3 for implanted phosphorus plateau values ≥4 × 1020 cm-3, irrespective of the post-implantation annealing method. Implantation produces an increase of the lattice parameter in the bulk 4H-SiC underneath the phosphorus-implanted layer. Microwave and conventional annealing produce a further increase of the lattice parameter in such a depth region and an equivalent recovered lattice in the phosphorus-implanted layers.

  17. Dental Implants

    MedlinePlus

    ... Procedures Dental Implants Dentures Direct Bonding Implants versus Bridges Orthodontics and Aligners Periodontal Plastic Surgery Porcelain Crowns Porcelain Fixed Bridges Porcelain Veneers Repairing Chipped Teeth Teeth Whitening Tooth- ...

  18. Ion implanted and laser processed solar cells made from EFG ribbon

    SciTech Connect

    Ladd, L. A.; Ravi, K. V.; Narayan, J.

    1980-01-01

    The use of ion implantation and laser processing has a number of conceptual advantages which could result in a low-cost process for manufacturing high performance solar cells from EFG ribbon. Samples were phosphorus ion implanted, laser processed using either a pulse large area ruby laser or a scanned YAG laser with a second harmonic generator, and then processed into solar cells. Many of the samples had high reverse leakage and it was determined that this was due to too high a laser processing power. This effect was determined to be more severe for the scanned YAG laser, and is thought to be due to point defects. Cells were made from EFG ribbon with a low laser energy density which had efficiencies of up to 10% at AMI demonstrating the feasibility of this approach. High efficiencies should be attainable by optimizing the laser processing parameters.

  19. Benefits and Risks of Cochlear Implants

    MedlinePlus

    ... in aircraft interact in unpredictable ways with other computer systems Will have to be careful of static electricity. Static electricity may temporarily or permanently damage a cochlear implant. It ... computer monitors, or synthetic fabric. For more details regarding ...

  20. Synthetic oils

    NASA Technical Reports Server (NTRS)

    Hatton, R. E.

    1973-01-01

    Synthetic lubricants are discussed by chemical class and their general strengths and weaknesses in terms of lubrication properties are analyzed. Comparative ratings are given for 14 chemical classes and are used as a guide for lubricant selection. The effects of chemical structure on the properties of the lubricant are described with special emphasis on thermal stability. The diversity of synthetic lubricants which is provided by the wide range of properties permits many applications, some of which are reported.

  1. Cochlear Implants

    MedlinePlus

    ... electrodes are inserted. The electronic device at the base of the electrode array is then placed under ... FDA approval for implants The Food and Drug Administration (FDA) regulates cochlear implant devices for both adults ...

  2. Dental Implants.

    PubMed

    Zohrabian, Vahe M; Sonick, Michael; Hwang, Debby; Abrahams, James J

    2015-10-01

    Dental implants restore function to near normal in partially or completely edentulous patients. A root-form implant is the most frequently used type of dental implant today. The basis for dental implants is osseointegration, in which osteoblasts grow and directly integrate with the surface of titanium posts surgically embedded into the jaw. Radiologic assessment is critical in the preoperative evaluation of the dental implant patient, as the exact height, width, and contour of the alveolar ridge must be determined. Moreover, the precise locations of the maxillary sinuses and mandibular canals, as well as their relationships to the site of implant surgery must be ascertained. As such, radiologists must be familiar with implant design and surgical placement, as well as augmentation procedures utilized in those patients with insufficient bone in the maxilla and mandible to support dental implants.

  3. Microwave annealing, a low-thermal-budget process for dopant activation in phosphorus-implanted MOSFET devices

    NASA Astrophysics Data System (ADS)

    Lim, Cheol-Min; Cho, Won-Ju

    2016-09-01

    In this work, we investigated a low-thermal-budget dopant activation process based on microwave annealing (MWA) of phosphorus ions implanted by plasma doping and compared the proposed technique with the conventional furnace annealing and the rapid thermal annealing processes. We fabricated p-n junction diodes and metal-oxide-semiconductor field-effect transistors (MOSFETs) on silicon and silicon-on-insulator substrates, respectively, in order to examine the dopant activation resulting from MWA. The investigated low-thermal-budget MWA technique proved effective for implanted dopant atom activation and diffusion suppression. In addition, a good interface property between the gate oxide and the silicon channel was achieved. Thus, low-thermal-budget MWA is a promising and effective method for the fabrication of highly-integrated semiconductor devices.

  4. Synthetic environments

    NASA Astrophysics Data System (ADS)

    Lukes, George E.; Cain, Joel M.

    1996-02-01

    The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.

  5. [Hearing implants].

    PubMed

    Stokroos, Robert J; George, Erwin L J

    2013-01-01

    In the Netherlands, more than 1.5 million people suffer from sensorineural hearing loss or deafness. However, fitting conventional hearing aids does not provide a solution for everyone. In recent decades, developments in medical technology have produced implantable and other devices that restore both sensorineural and conductive hearing losses. These hearing devices can be categorized into bone conductive devices, implantable middle ear prostheses, cochlear implants and auditory brainstem implants. Furthermore, new implants aimed at treating tinnitus and loss of vestibular function have recently been developed.

  6. Synthetic Jets

    NASA Technical Reports Server (NTRS)

    Milanovic, Ivana M.

    2003-01-01

    Current investigation of synthetic jets and synthetic jets in cross-flow examined the effects of orifice geometry and dimensions, momentum-flux ratio, cluster of orifices, pitch and yaw angles as well as streamwise development of the flow field. This comprehensive study provided much needed experimental information related to the various control strategies. The results of the current investigation on isolated and clustered synthetic jets with and without cross-flow will be further analyzed and documented in detail. Presentations at national conferences and publication of peer- reviewed journal articles are also expected. Projected publications will present both the mean and turbulent properties of the flow field, comparisons made with the data available in an open literature, as well as recommendations for the future work.

  7. Synthetic Astrobiology

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.

    2015-01-01

    Synthetic biology - the design and construction of new biological parts and systems and the redesign of existing ones for useful purposes - has the potential to transform fields from pharmaceuticals to fuels. Our lab has focused on the potential of synthetic biology to revolutionize all three major parts of astrobiology: Where do we come from? Where are we going? and Are we alone? For the first and third, synthetic biology is allowing us to answer whether the evolutionary narrative that has played out on planet earth is likely to have been unique or universal. For example, in our lab we are re-evolving the biosynthetic pathways of amino acids in order to understand potential capabilities of an early organism with a limited repertoire of amino acids and developing techniques for the recovery of metals from spent electronics on other planetary bodies. In the future synthetic biology will play an increasing role in human activities both on earth, in fields as diverse as human health and the industrial production of novel bio-composites. Beyond earth, we will rely increasingly on biologically-provided life support, as we have throughout our evolutionary history. In order to do this, the field will build on two of the great contributions of astrobiology: studies of the origin of life and life in extreme environments.

  8. Synthetic Astrobiology

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.

    2016-01-01

    Synthetic biology - the design and construction of new biological parts and systems and the redesign of existing ones for useful purposes - has the potential to transform fields from pharmaceuticals to fuels. Our lab has focused on the potential of synthetic biology to revolutionize all three major parts of astrobiology: Where do we come from? Where are we going? and Are we alone? For the first and third, synthetic biology is allowing us to answer whether the evolutionary narrative that has played out on planet earth is likely to have been unique or universal. For example, in our lab we are re-evolving the biosynthetic pathways of amino acids in order to understand potential capabilities of an early organism with a limited repertoire of amino acids and developing techniques for the recovery of metals from spent electronics on other planetary bodies. And what about the limits for life? Can we create organisms that expand the envelope for life? In the future synthetic biology will play an increasing role in human activities both on earth, in fields as diverse as human health and the industrial production of novel bio-composites. Beyond earth, we will rely increasingly on biologically-provided life support, as we have throughout our evolutionary history. In order to do this, the field will build on two of the great contributions of astrobiology: studies of the origin of life and life in extreme environments.

  9. Implantable Microimagers

    PubMed Central

    Ng, David C.; Tokuda, Takashi; Shiosaka, Sadao; Tano, Yasuo; Ohta, Jun

    2008-01-01

    Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications.

  10. Ion sources for energy extremes of ion implantation.

    PubMed

    Hershcovitch, A; Johnson, B M; Batalin, V A; Kropachev, G N; Kuibeda, R P; Kulevoy, T V; Kolomiets, A A; Pershin, V I; Petrenko, S V; Rudskoy, I; Seleznev, D N; Bugaev, A S; Gushenets, V I; Litovko, I V; Oks, E M; Yushkov, G Yu; Masunov, E S; Polozov, S M; Poole, H J; Storozhenko, P A; Svarovski, A Ya

    2008-02-01

    For the past four years a joint research and development effort designed to develop steady state, intense ion sources has been in progress with the ultimate goal to develop ion sources and techniques that meet the two energy extreme range needs of meV and hundreads of eV ion implanters. This endeavor has already resulted in record steady state output currents of high charge state of antimony and phosphorus ions: P(2+) [8.6 pmA (particle milliampere)], P(3+) (1.9 pmA), and P(4+) (0.12 pmA) and 16.2, 7.6, 3.3, and 2.2 pmA of Sb(3+)Sb(4+), Sb(5+), and Sb(6+) respectively. For low energy ion implantation, our efforts involve molecular ions and a novel plasmaless/gasless deceleration method. To date, 1 emA (electrical milliampere) of positive decaborane ions was extracted at 10 keV and smaller currents of negative decaborane ions were also extracted. Additionally, boron current fraction of over 70% was extracted from a Bernas-Calutron ion source, which represents a factor of 3.5 improvement over currently employed ion sources.

  11. Histrelin Implant

    MedlinePlus

    ... response to histrelin implant. Your blood sugar and glycosylated hemoglobin (HbA1c) should be checked regularly.Ask your pharmacist any questions you have about histrelin implant.It is important for you to keep a written list of all of the prescription and ...

  12. Synthetic Cathinones ("Bath Salts")

    MedlinePlus

    ... still unknown about how synthetic cathinones affect the human brain. Researchers do know that synthetic cathinones are chemically ... of the chemicals in synthetic cathinones affect the human brain. Synthetic cathinones can cause: nosebleeds paranoia increased sociability ...

  13. Synthetic Cannabinoids.

    PubMed

    Mills, Brooke; Yepes, Andres; Nugent, Kenneth

    2015-07-01

    Synthetic cannabinoids (SCBs), also known under the brand names of "Spice," "K2," "herbal incense," "Cloud 9," "Mojo" and many others, are becoming a large public health concern due not only to their increasing use but also to their unpredictable toxicity and abuse potential. There are many types of SCBs, each having a unique binding affinity for cannabinoid receptors. Although both Δ-tetrahydrocannabinol (THC) and SCBs stimulate the same receptors, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), studies have shown that SCBs are associated with higher rates of toxicity and hospital admissions than is natural cannabis. This is likely due to SCBs being direct agonists of the cannabinoid receptors, whereas THC is a partial agonist. Furthermore, the different chemical structures of SCBs found in Spice or K2 may interact in unpredictable ways to elicit previously unknown, and the commercial products may have unknown contaminants. The largest group of users is men in their 20s who participate in polydrug use. The most common reported toxicities with SCB use based on studies using Texas Poison Control records are tachycardia, agitation and irritability, drowsiness, hallucinations, delusions, hypertension, nausea, confusion, dizziness, vertigo and chest pain. Acute kidney injury has also been strongly associated with SCB use. Treatment mostly involves symptom management and supportive care. More research is needed to identify which contaminants are typically found in synthetic marijuana and to understand the interactions between different SBCs to better predict adverse health outcomes.

  14. Cochlear implant

    MedlinePlus

    ... implant. These specialists may include: Audiologists Speech therapists Ear, nose, and throat doctors (otolaryngologists) This is a very important part of the process. You will need to work closely with your team of specialists to get ...

  15. Cochlear Implants

    MedlinePlus

    ... additional visits are needed for activating, adjusting, and programming the various electrodes that have been implanted. Also, ... to the center for checkups once the final programming is made to the speech processor. Both children ...

  16. Synthetic Brainbows

    PubMed Central

    Wan, Y.; Otsuna, H.; Hansen, C.

    2014-01-01

    Brainbow is a genetic engineering technique that randomly colorizes cells. Biological samples processed with this technique and imaged with confocal microscopy have distinctive colors for individual cells. Complex cellular structures can then be easily visualized. However, the complexity of the Brainbow technique limits its applications. In practice, most confocal microscopy scans use different florescence staining with typically at most three distinct cellular structures. These structures are often packed and obscure each other in rendered images making analysis difficult. In this paper, we leverage a process known as GPU framebuffer feedback loops to synthesize Brainbow-like images. In addition, we incorporate ID shuffing and Monte-Carlo sampling into our technique, so that it can be applied to single-channel confocal microscopy data. The synthesized Brainbow images are presented to domain experts with positive feedback. A user survey demonstrates that our synthetic Brainbow technique improves visualizations of volume data with complex structures for biologists. PMID:25018576

  17. Contraceptive implants.

    PubMed

    McDonald-Mosley, Raegan; Burke, Anne E

    2010-03-01

    Implantable contraception has been extensively used worldwide. Implants are one of the most effective and reversible methods of contraception available. These devices may be particularly appropriate for certain populations of women, including women who cannot use estrogen-containing contraception. Implants are safe for use by women with many chronic medical problems. The newest implant, Implanon (Organon International, Oss, The Netherlands), is the only device currently available in the United States and was approved in 2006. It is registered for 3 years of pregnancy prevention. Contraceptive implants have failure rates similar to tubal ligation, and yet they are readily reversible with a return to fertility within days of removal. Moreover, these contraceptive devices can be safely placed in the immediate postpartum period, ensuring good contraceptive coverage for women who may be at risk for an unintended pregnancy. Irregular bleeding is a common side effect for all progestin-only contraceptive implants. Preinsertion counseling should address possible side effects, and treatment may be offered to women who experience prolonged or frequent bleeding.

  18. Treatment of Infected Facial Implants.

    PubMed

    Mohan, Kriti; Cox, Joshua A; Dickey, Ryan M; Gravina, Paula; Echo, Anthony; Izaddoost, Shayan A; Nguyen, Anh H

    2016-05-01

    Alloplastic facial implants have a wide range of uses to achieve the appropriate facial contour. A variety of materials such as metals, polymers, ceramics and synthetic injectable fillers are available to the reconstructive and aesthetic surgeon. Besides choosing the right surgical technique and the adequate material, the surgeon must be prepared to treat complications. Infection is an uncommon but serious complication that can cause displeasing consequences for the patient. There are few references in literature regarding treatment and management of facial implant-related infections. This study aims to discuss the role of biofilm in predisposing alloplastic materials to infection, to provide a review of literature, to describe our own institutional experience, and to define a patient care pathway for facial implant-associated infection. PMID:27152100

  19. Probing the carrier concentration profiles in phosphorus-implanted germanium using infrared spectroscopic ellipsometry

    SciTech Connect

    D'Costa, Vijay Richard Yeo, Yee-Chia

    2015-02-21

    Spectroscopic ellipsometry with photon energy in the 0.045–0.65 eV range was used to investigate germanium samples implanted with 30 keV phosphorus ions and annealed at 700 °C. The infrared response of implanted layers is dominated by free carrier absorption which is modeled using a Drude oscillator. The carrier concentration profiles were modeled using an error function, and compared with those obtained by electrochemical capacitance-voltage profiling and secondary ion mass spectrometry. In the flat region of the carrier concentration profile, average carrier concentration and mobility of 1.40 × 10{sup 19} cm{sup −3} and 336 cm{sup 2}V{sup −1}s{sup −1}, respectively, were obtained. A phosphorus diffusivity of ∼1.2 × 10{sup −13} cm{sup 2}/s was obtained. The mobility versus carrier concentration relationships obtained for the implanted samples are close to the empirical relationship for bulk Ge.

  20. Synthetic peptides.

    PubMed

    Francis, M J

    1996-01-01

    Efforts to produce more stable and defined vaccines have concentrated on studying, in detail, the immune response to many infectious diseases in order to identify the antigenic sites on the pathogens that are involved in stimulating protective immumty. Armed with this knowledge, it is possible to mimic such sites by producing short chains of amino acids (peptides) and to use these as the basis for novel vaccines. The earliest documented work on peptide immunization is actually for a plant virus, tobacco mosaic virus. In 1963, Anderer (1) demonstrated that rabbit antibodies to an isolated hexapeptide fragment from the virus-coat protein coupled to bovine serum albumm would neutralize the infectious vn-us in culture. Two years later, he used a synthetically produced copy of the same peptide to confirm this observation. This was pioneering work, and it was over 10 years before the next example of a peptide that elicited antivirus antibody appeared following work by Sela and his colleagues (2) on a virus, MS2 bacteriophage, which infects bacteria. The emergence of more accessible techniques for sequencing proteins in 1977, coupled with the ability to synthesize readily peptides already developed in 1963, heralded a decade of intensive research into experimental peptide vaccines. The first demonstration that peptides could elicit protective immunity in vivo, in addition to neutralizing activity in vitro, was obtained using a peptide from the VP1 coat protein of foot-and-mouth disease virus (FMDV) in 1982, with the guinea pig as a laboratory animal model (3, 4). PMID:21359696

  1. Cochlear Implants

    MedlinePlus

    ... outside of the body, behind the ear. A second part is surgically placed under 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

  2. Facial implants.

    PubMed

    Arcuri, M R; Rubenstein, J T

    1998-01-01

    The application of endosseous dental implants for the retention and stabilization of extraoral prostheses and hearing aids has been shown to be effective functionally and aesthetically. Implants have reduced the need for adhesive use, simplifying cleaning procedures and thus extending the life of the prosthesis. Implant-retained prostheses have provided patients the opportunity to participate in routine activities such as work, shopping, swimming, and jogging with less fear of losing their prosthesis. The implants' impact on patients has resulted in their ability to function in society with confidence that their defects will be less noticeable and their ability to respond to the environment enhanced. The culmination of these effects have without doubt improved the overall quality of life for patients. As with any new technology, its application will encounter unanticipated problems and some limitations in use. As the art and science of this technique evolve, however, it is anticipated that it will result in the ability to provide improved health care for patients.

  3. Impact of implanted phosphorus on the diffusivity of boron and its applicability to silicon solar cells

    SciTech Connect

    Schrof, Julian Müller, Ralph; Benick, Jan; Hermle, Martin; Reedy, Robert C.

    2015-07-28

    Boron diffusivity reduction in extrinsically doped silicon was investigated in the context of a process combination consisting of BBr{sub 3} furnace diffusion and preceding Phosphorus ion implantation. The implantation of Phosphorus leads to a substantial blocking of Boron during the subsequent Boron diffusion. First, the influences of ion implantation induced point defects as well as the initial P doping on B diffusivity were studied independently. Here, it was found that not the defects created during ion implantation but the P doping itself results in the observed B diffusion retardation. The influence of the initial P concentration was investigated in more detail by varying the P implantation dose. A secondary ion mass spectrometry (SIMS) analysis of the BSG layer after the B diffusion revealed that the B diffusion retardation is not due to potential P content in the BSG layer but rather caused by the n-type doping of the crystalline silicon itself. Based on the observations the B diffusion retardation was classified into three groups: (i) no reduction of B diffusivity, (ii) reduced B diffusivity, and (iii) blocking of the B diffusion. The retardation of B diffusion can well be explained by the phosphorus doping level resulting in a Fermi level shift and pairing of B and P ions, both reducing the B diffusivity. Besides these main influences, there are probably additional transient phenomena responsible for the blocking of boron. Those might be an interstitial transport mechanism caused by P diffusion that reduces interstitial concentration at the surface or the silicon/BSG interface shift due to oxidation during the BBr{sub 3} diffusion process. Lifetime measurements revealed that the residual (non-blocked) B leads to an increased dark saturation current density in the P doped region. Nevertheless, electrical quality is on a high level and was further increased by reducing the B dose as well as by removing the first few nanometers of the silicon surface after

  4. Impact of implanted phosphorus on the diffusivity of boron and its applicability to silicon solar cells

    NASA Astrophysics Data System (ADS)

    Schrof, Julian; Müller, Ralph; Reedy, Robert C.; Benick, Jan; Hermle, Martin

    2015-07-01

    Boron diffusivity reduction in extrinsically doped silicon was investigated in the context of a process combination consisting of BBr3 furnace diffusion and preceding Phosphorus ion implantation. The implantation of Phosphorus leads to a substantial blocking of Boron during the subsequent Boron diffusion. First, the influences of ion implantation induced point defects as well as the initial P doping on B diffusivity were studied independently. Here, it was found that not the defects created during ion implantation but the P doping itself results in the observed B diffusion retardation. The influence of the initial P concentration was investigated in more detail by varying the P implantation dose. A secondary ion mass spectrometry (SIMS) analysis of the BSG layer after the B diffusion revealed that the B diffusion retardation is not due to potential P content in the BSG layer but rather caused by the n-type doping of the crystalline silicon itself. Based on the observations the B diffusion retardation was classified into three groups: (i) no reduction of B diffusivity, (ii) reduced B diffusivity, and (iii) blocking of the B diffusion. The retardation of B diffusion can well be explained by the phosphorus doping level resulting in a Fermi level shift and pairing of B and P ions, both reducing the B diffusivity. Besides these main influences, there are probably additional transient phenomena responsible for the blocking of boron. Those might be an interstitial transport mechanism caused by P diffusion that reduces interstitial concentration at the surface or the silicon/BSG interface shift due to oxidation during the BBr3 diffusion process. Lifetime measurements revealed that the residual (non-blocked) B leads to an increased dark saturation current density in the P doped region. Nevertheless, electrical quality is on a high level and was further increased by reducing the B dose as well as by removing the first few nanometers of the silicon surface after the BBr3

  5. Cell microencapsulation with synthetic polymers

    PubMed Central

    Olabisi, Ronke M

    2015-01-01

    The encapsulation of cells into polymeric microspheres or microcapsules has permitted the transplantation of cells into human and animal subjects without the need for immunosuppressants. Cell-based therapies use donor cells to provide sustained release of a therapeutic product, such as insulin, and have shown promise in treating a variety of diseases. Immunoisolation of these cells via microencapsulation is a hotly investigated field, and the preferred material of choice has been alginate, a natural polymer derived from seaweed due to its gelling conditions. Although many natural polymers tend to gel in conditions favorable to mammalian cell encapsulation, there remain challenges such as batch to batch variability and residual components from the original source that can lead to an immune response when implanted into a recipient. Synthetic materials have the potential to avoid these issues; however, historically they have required harsh polymerization conditions that are not favorable to mammalian cells. As research into microencapsulation grows, more investigators are exploring methods to microencapsulate cells into synthetic polymers. This review describes a variety of synthetic polymers used to microencapsulate cells. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 846–859, 2015. PMID:24771675

  6. Short Implants: New Horizon in Implant Dentistry

    PubMed Central

    Gulati, Manisha; Garg, Meenu; Pathak, Chetan

    2016-01-01

    The choice of implant length is an essential factor in deciding the survival rates of these implants and the overall success of the prosthesis. Placing an implant in the posterior part of the maxilla and mandible has always been very critical due to poor bone quality and quantity. Long implants can be placed in association with complex surgical procedures such as sinus lift and bone augmentation. These techniques are associated with higher cost, increased treatment time and greater morbidity. Hence, there is need for a less invasive treatment option in areas of poor bone quantity and quality. Data related to survival rates of short implants, their design and prosthetic considerations has been compiled and structured in this manuscript with emphasis on the indications, advantages of short implants and critical biomechanical factors to be taken into consideration when choosing to place them. Studies have shown that comparable success rates can be achieved with short implants as those with long implants by decreasing the lateral forces to the prosthesis, eliminating cantilevers, increasing implant surface area and improving implant to abutment connection. Short implants can be considered as an effective treatment alternative in resorbed ridges. Short implants can be considered as a viable treatment option in atrophic ridge cases in order to avoid complex surgical procedures required to place long implants. With improvement in the implant surface geometry and surface texture, there is an increase in the bone implant contact area which provides a good primary stability during osseo-integration. PMID:27790598

  7. High Mobility SiGe/Si Transistor Structures on Sapphire Substrates Using Ion Implantation

    NASA Technical Reports Server (NTRS)

    Alterovitz, S. A.; Mueller, C. H.; Croke, E. T.

    2003-01-01

    High mobility n-type SiGe/Si transistor structures have been fabricated on sapphire substrates by ion implanting phosphorus ions into strained 100 Angstrom thick silicon channels for the first time. The strained Si channels were sandwiched between Si(sub 0.7)Ge(sub 0.3) layers, which, in turn, were deposited on Si(sub 0.7)Ge(sub 0.3) virtual substrates and graded SiGe buffer layers. After the molecular beam epitaxy (MBE) film growth process was completed, ion thick silicon channels implantation and post-annealing were used to introduce donors. The phosphorous ions were preferentially located in the Si channel at a peak concentration of approximately 1x10(exp 18)/cu cm. Room temperature electron mobilities exceeding 750 sq cm/V-sec at carrier densities of 1x10(exp 12)/sq cm were measured. Electron concentration appears to be the key factor that determines mobility, with the highest mobility observed for electron densities in the 1 - 2x10(exp 12)/sq cm range.

  8. In vivo biofilm on the surface of a surgical mesh implant.

    PubMed

    Reśliński, Adrian; Mikucka, Agnieszka; Szmytkowski, Jakub; Gospodarek, Eugenia; Dabrowiecki, Stanisław

    2009-01-01

    Mesh hernioplasty is among the most frequently performed surgical procedures. The introduction of mesh implants has decreased recurrence rates, but the use of synthetic materials carries the risk of infection and biofilm formation. This paper presents the course of the disease in the case of biofilm formation on the surface of an implanted surgical mesh. Antimicrobial therapy and partial removal of the implant were unsuccessful. Recurring surgical site infection could be managed only through total excision of the infected implant.

  9. Materials and technologies for soft implantable neuroprostheses

    NASA Astrophysics Data System (ADS)

    Lacour, Stéphanie P.; Courtine, Grégoire; Guck, Jochen

    2016-10-01

    Implantable neuroprostheses are engineered systems designed to restore or substitute function for individuals with neurological deficits or disabilities. These systems involve at least one uni- or bidirectional interface between a living neural tissue and a synthetic structure, through which information in the form of electrons, ions or photons flows. Despite a few notable exceptions, the clinical dissemination of implantable neuroprostheses remains limited, because many implants display inconsistent long-term stability and performance, and are ultimately rejected by the body. Intensive research is currently being conducted to untangle the complex interplay of failure mechanisms. In this Review, we emphasize the importance of minimizing the physical and mechanical mismatch between neural tissues and implantable interfaces. We explore possible materials solutions to design and manufacture neurointegrated prostheses, and outline their immense therapeutic potential.

  10. Bone formation on synthetic precursors of hydroxyapatite.

    PubMed

    Suzuki, O; Nakamura, M; Miyasaka, Y; Kagayama, M; Sakurai, M

    1991-05-01

    The aim of this study was to investigate the reaction of skeletal tissue to various synthetic calcium phosphate (Ca-P) compounds in vivo. Five synthetic Ca-P compounds were implanted into the subperiosteal area of the calvaria of 7-week-old BALB/c mice for one to 15 weeks. Synthetic compounds were dicalcium phosphate (DCP), octacalcium phosphate (OCP), amorphous calcium phosphate (ACP), Ca-deficient hydroxyapatite and hydroxyapatile (HA). Implanted DCP, OCP and ACP were found to be converted to apatitic phase by x-ray microdiffraction analysis using undecalcified specimens. Structure of bone was found out on all of Ca-P compounds eventually at late stage under the light microscope, but the rate of bone formation calculated from a number of experiments varied on respective synthetic Ca-P compound. It was high as 80% for DCP, OCP and ACP, but was low as 5.6% for Ca-deficient HA, and no reaction was found for HA at the stage of 3 weeks. Fine filaments and granular materials in the newly formed bone matrix were detected at 7 days around the remnants of OCP particles which already converted to apatitic phase by ultrastructural study of decalcified specimens. These structures were very similar to the components of bone nodules seen in intramembranous osteogenesis. It is postulated that the precursors of HA have an important role in intramembranous osteogenesis.

  11. Synthetic cannabinoids and potential reproductive consequences

    PubMed Central

    Sun, Xiaofei; Dey, Sudhansu K.

    2013-01-01

    Increases in emergency room visits due to abuse of designer drugs, popularly known by the street names “K2” and “Spice,” are a cause for social, judicial, and clinical concerns. The psychoactive components in these herbal drugs mainly consist of different synthetic cannabinoids, and users of these street drugs are primarily within the age group of 12 to 20 years old. The abusive use of synthetic cannabinoids results in anxiety, nausea, vomiting, tachycardia, elevated blood pressure, tremors, seizures, hallucinations, and paranoid behavior, but the effects of maternal use of synthetic cannabinoids during pregnancy are ambiguous due to limited studies in humans and a relative short history of the drugs. In this review, we discuss the known and potential adverse effects of synthetic cannabinoids on human pregnancy using knowledge gathered from studies in mice and limited studies in humans. In mice, multiple sites and stages of pregnancy are potential targets of synthetic cannabinoids, including preimplantation embryo development, oviductal embryo transport, implantation, placentation, and parturition. It is anticipated that maternal use of synthetic cannabinoids would result in severely compromised female fertility and pregnancy outcome. PMID:23827241

  12. Plant synthetic biology.

    PubMed

    Liu, Wusheng; Stewart, C Neal

    2015-05-01

    Plant synthetic biology is an emerging field that combines engineering principles with plant biology toward the design and production of new devices. This emerging field should play an important role in future agriculture for traditional crop improvement, but also in enabling novel bioproduction in plants. In this review we discuss the design cycles of synthetic biology as well as key engineering principles, genetic parts, and computational tools that can be utilized in plant synthetic biology. Some pioneering examples are offered as a demonstration of how synthetic biology can be used to modify plants for specific purposes. These include synthetic sensors, synthetic metabolic pathways, and synthetic genomes. We also speculate about the future of synthetic biology of plants.

  13. [SYNTHETIC PEPTIDE VACCINES].

    PubMed

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested.

  14. [From synthetic biology to synthetic humankind].

    PubMed

    Nouvel, Pascal

    2015-01-01

    In this paper, we propose an historical survey of the expression "synthetic biology" in order to identify its main philosophical components. The result of the analysis is then used to investigate the meaning of the notion of "synthetic man". It is shown that both notions share a common philosophical background that can be summed up by the short but meaningful assertion: "biology is technology". The analysis allows us to distinguish two notions that are often confused in transhumanist literature: the notion of synthetic man and the notion of renewed man. The consequences of this crucial distinction are discussed.

  15. Fibrillogenesis in Continuously Spun Synthetic Collagen Fiber

    PubMed Central

    Caves, Jeffrey M.; Kumar, Vivek A.; Wen, Jing; Cui, Wanxing; Martinez, Adam; Apkarian, Robert; Coats, Julie E.; Berland, Keith; Chaikof, Elliot L.

    2013-01-01

    The universal structural role of collagen fiber networks has motivated the development of collagen gels, films, coatings, injectables, and other formulations. However, reported synthetic collagen fiber fabrication schemes have either culminated in short, discontinuous fiber segments at unsuitably low production rates, or have incompletely replicated the internal fibrillar structure that dictates fiber mechanical and biological properties. We report a continuous extrusion system with an off-line phosphate buffer incubation step for the manufacture of synthetic collagen fiber. Fiber with a cross-section of 53±14 by 21±3 µm and an ultimate tensile strength of 94±19 MPa was continuously produced at 60 m/hr from an ultrafiltered monomeric collagen solution. The effect of collagen solution concentration, flow rate, and spinneret size on fiber size was investigated. The fiber was further characterized by microdifferential scanning calorimetry, transmission electron microscopy (TEM), second harmonic generation (SHG) analysis, and in a subcutaneous murine implant model. Calorimetry demonstrated stabilization of the collagen triple helical structure, while TEM and SHG revealed a dense, axially aligned D-periodic fibril structure throughout the fiber cross-section. Implantation of glutaraldehyde crosslinked and non-crosslinked fiber in the subcutaneous tissue of mice demonstrated limited inflammatory response and biodegradation after a 6-week implant period. PMID:20024969

  16. UK national survey of enucleation, evisceration and orbital implant trends

    PubMed Central

    Viswanathan, P; Sagoo, Mandeep S; Olver, Jane M

    2007-01-01

    Aim To evaluate current clinical practice in the UK in the management of the anophthalmic socket; choice of enucleation, evisceration, type of orbital implant, wrap, motility pegging and complications. Methods All consultant ophthalmologists in the UK were surveyed by postal questionnaire. Questions included their practice subspecialty and number of enucleations and eviscerations performed in 2003. Specific questions addressed choice of implant, wrap, motility pegging and complications. Results 456/896 (51%) consultants responded, of which 162 (35%) had a specific interest in oculoplastics, lacrimal, orbits or oncology. Only 243/456 (53%) did enucleations or eviscerations. 92% inserted an orbital implant after primary enucleation, 69% after non‐endophthalmitis evisceration, whereas only 43% did so after evisceration for endophthalmitis (50% as a delayed procedure). 55% used porous orbital implants (porous polyethylene, hydroxyapatite or alumina) as their first choice and 42% used acrylic. Most implants inserted were spherical, sized 18–20 mm in diameter. 57% wrapped the implant after enucleation, using salvaged autogenous sclera (20%), donor sclera (28%) and synthetic Vicryl or Mersilene mesh (42%). A minority (7%) placed motility pegs in selected cases, usually as a secondary procedure. 14% of respondents reported implant exposure for each type of procedure and extrusion was reported by 4% after enucleation and 3% after evisceration. Conclusions This survey highlights contemporary anophthalmic socket practice in the UK. Most surgeons use porous orbital implants with a synthetic wrap after enucleation and only few perform motility pegging. PMID:17151061

  17. Nanotechnology Approaches for Better Dental Implants

    PubMed Central

    Tomsia, Antoni P.; Launey, Maximilien E.; Lee, Janice S.; Mankani, Mahesh H.; Wegst, Ulrike G.K.; Saiz, Eduardo

    2011-01-01

    The combined requirements imposed by the enormous scale and overall complexity of designing new implants or complete organ regeneration are well beyond the reach of present technology in many dimensions, including nanoscale, as we do not yet have the basic knowledge required to achieve these goals. The need for a synthetic implant to address multiple physical and biological factors imposes tremendous constraints on the choice of suitable materials. There is a strong belief that nanoscale materials will produce a new generation of implant materials with high efficiency, low cost, and high volume. The nanoscale in materials processing is truly a new frontier. Metallic dental implants have been successfully used for decades but they have serious shortcomings related to their osseointegration and the fact that their mechanical properties do not match those of bone. This paper reviews recent advances in the fabrication of novel coatings and nanopatterning of dental implants. It also provides a general summary of the state of the art in dental implant science and describes possible advantages of nanotechnology for further improvements. The ultimate goal is to produce materials and therapies that will bring state-of-the-art technology to the bedside and improve quality of life and current standards of care. PMID:21464998

  18. Nanotechnology approaches to improve dental implants.

    PubMed

    Tomisa, Antoni P; Launey, Maximilien E; Lee, Janice S; Mankani, Mahesh H; Wegst, Ulrike G K; Saiz, Eduardo

    2011-01-01

    The requirements imposed by the enormous scale and overall complexity of designing new implants or complete organ regeneration are well beyond the reach of present technology in many dimensions, including nanoscale, as researchers do not yet have the basic knowledge required to achieve these goals. The need for a synthetic implant to address multiple physical and biologic factors imposes tremendous constraints on the choice of suitable materials. There is a strong belief that nanoscale materials will produce a new generation of implant materials with high efficiency, low cost, and high volume. The nanoscale in materials processing is truly a new frontier. Metallic dental implants have been used successfully for decades, but they have serious shortcomings related to their osseointegration and the fact that their mechanical properties do not match those of bone. This paper reviews recent advances in the fabrication of novel coatings and nanopatterning of dental implants. It also provides a general summary of the state of the art in dental implant science and describes possible advantages of nanotechnology for future improvements. The ultimate goal is to produce materials and therapies that will bring state-of-the-art technology to the bedside and improve quality of life and current standards of care.

  19. Evolvable synthetic neural system

    NASA Technical Reports Server (NTRS)

    Curtis, Steven A. (Inventor)

    2009-01-01

    An evolvable synthetic neural system includes an evolvable neural interface operably coupled to at least one neural basis function. Each neural basis function includes an evolvable neural interface operably coupled to a heuristic neural system to perform high-level functions and an autonomic neural system to perform low-level functions. In some embodiments, the evolvable synthetic neural system is operably coupled to one or more evolvable synthetic neural systems in a hierarchy.

  20. Synthetic cathinone abuse

    PubMed Central

    Capriola, Michael

    2013-01-01

    The abuse of synthetic cathinones, widely known as bath salts, has been increasing since the mid-2000s. These substances are derivatives of the naturally occurring compound cathinone, which is the primary psychoactive component of khat. The toxicity of synthetic cathinones includes significant sympathomimetic effects, as well as psychosis, agitation, aggression, and sometimes violent and bizarre behavior. Mephedrone and methylenedioxypyrovalerone are currently the predominantly abused synthetic cathinones. PMID:23869180

  1. [SYNTHETIC PEPTIDE VACCINES].

    PubMed

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested. PMID:27145593

  2. Implant success!!!.....simplified.

    PubMed

    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.

  3. [Biomaterials in cochlear implants].

    PubMed

    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.

  4. Variable Synthetic Capacitance

    NASA Technical Reports Server (NTRS)

    Kleinberg, L. L.

    1986-01-01

    Feedback amplifier circuit synthesizes electronically variable capacitance. Variable Synthetic Capacitor is amplifier circuit with follower/feedback configuration. Effective input capacitance depends on input set current. If synthetic capacitor is connected across resonant element of oscillator, oscillator frequency controlled via input set current. Circuit especially suitable for fine frequency adjustments of piezoelectric-crystal or inductor/capacitor resonant oscillators.

  5. Breast reconstruction - implants

    MedlinePlus

    ... visits, your surgeon injects a small amount of saline (salt water) through the valve into the expander. ... breast implants. Implants may be filled with either saline or a silicone gel. You may have another ...

  6. An in vivo assessment of the effects of using different implant abutment occluding materials on implant microleakage and the peri-implant microbiome

    NASA Astrophysics Data System (ADS)

    Rubino, Caroline

    Microleakage may be a factor in the progression of peri-implant pathology. Microleakage in implant dentistry refers to the passage of bacteria, fluids, molecules or ions between the abutment-implant interface to and from the surrounding periodontal tissues. This creates a zone of inflammation and reservoir of bacteria at the implant-abutment interface. Bone loss typically occurs within the first year of abutment connection and then stabilizes. It has not yet been definitively proven that the occurrence of microleakage cannot contribute to future bone loss or impede the treatment of peri-implant disease. Therefore, strategies to reduce or eliminate microleakage are sought out. Recent evidence demonstrates that the type of implant abutment channel occluding material can affect the amount of microleakage in an in vitro study environment. Thus, we hypothesize that different abutment screw channel occluding materials will affect the amount of observed microleakage, vis-a-vis the correlation between the microflora found on the abutment screw channel occluding material those found in the peri-implant sulcus. Additional objectives include confirming the presence of microleakage in vivo and assessing any impact that different abutment screw channel occluding materials may have on the peri-implant microbiome. Finally, the present study provides an opportunity to further characterize the peri-implant microbiome. Eight fully edentulous patients restored with at dental implants supporting screw-retained fixed hybrid prostheses were included in the study. At the initial appointment (T1), the prostheses were removed and the implants and prostheses were cleaned. The prostheses were then inserted with polytetrafluoroethylene tape (PTFE, TeflonRTM), cotton, polyvinyl siloxane (PVS), or synthetic foam as the implant abutment channel occluding material and sealed over with composite resin. About six months later (T2), the prostheses were removed and the materials collected. Paper

  7. [Pathology of implants].

    PubMed

    Mittermayer, C; Eblenkamp, M; Richter, H A; Zwadlo-Klarwasser, G; Bhardwaj, R S; Klosterhalfen, B

    2002-01-01

    Progress in the surgery of implants and biomaterials can be accomplished by: 1. Painstakingly analysing and registering of defaulting implants after explantation within a "National Registry of Implant Pathology". 2. Development of a DNA-microarray named "Implantat/Chronic Wound" in order to discover the differential transcriptional activities of cells brought into contact with different foreign surfaces. 3. Predictive cell-engineering combined with custom-made implant surfaces with the aim of optimal patient care.

  8. Integrative Performance Analysis of a Novel Bone Level Tapered Implant.

    PubMed

    Dard, M; Kuehne, S; Obrecht, M; Grandin, M; Helfenstein, J; Pippenger, B E

    2016-03-01

    Primary mechanical stability, as measured by maximum insertion torque and resonance frequency analysis, is generally considered to be positively associated with successful secondary stability and implant success. Primary implant stability can be affected by several factors, including the quality and quantity of available bone, the implant design, and the surgical procedure. The use of a tapered implant design, for instance, has been shown to result in good primary stability even in clinical scenarios where primary stability is otherwise difficult to achieve with traditional cylindrical implants-for example, in soft bone and for immediate placement in extraction sockets. In this study, bone-type specific drill procedures are presented for a novel Straumann bone level tapered implant that ensure maximum insertion torque values are kept within the range of 15 to 80 Ncm. The drill procedures are tested in vitro using polyurethane foam blocks of variable density, ex vivo on explanted porcine ribs (bone type 3), and finally in vivo on porcine mandibles (bone type 1). In each test site, adapted drill procedures are found to achieve a good primary stability. These results are further translated into a finite element analysis model capable of predicting primary stability of tapered implants. In conclusion, we have assessed the biomechanical behavior of a novel taper-walled implant in combination with a bone-type specific drill procedure in both synthetic and natural bone of various types, and we have developed an in silico model for predicting primary stability upon implantation. PMID:26927485

  9. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1984-01-01

    CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.

  10. Saga of synthetic rubber

    SciTech Connect

    Solo, R.A.

    1980-04-01

    The proposal to establish an Energy Mobilization Board and a synthetic fuels industry is reminiscent of World War II efforts to produce synthetic rubber. To avoid the mistakes made in the earlier effort, Mr. Solo suggests that the synthetic-fuel program should (1) use a more-successful technological development project as a model; (2) commit public funding and not rely on profit-oriented private enterprise; and (3) avoid entrusting social planning to single-purpose entities that have not been sensitive to social values. (DCK)

  11. Synthetic Base Fluids

    NASA Astrophysics Data System (ADS)

    Brown, M.; Fotheringham, J. D.; Hoyes, T. J.; Mortier, R. M.; Orszulik, S. T.; Randles, S. J.; Stroud, P. M.

    The chemical nature and technology of the main synthetic lubricant base fluids is described, covering polyalphaolefins, alkylated aromatics, gas-to-liquid (GTL) base fluids, polybutenes, aliphatic diesters, polyolesters, polyalkylene glycols or PAGs and phosphate esters.Other synthetic lubricant base oils such as the silicones, borate esters, perfluoroethers and polyphenylene ethers are considered to have restricted applications due to either high cost or performance limitations and are not considered here.Each of the main synthetic base fluids is described for their chemical and physical properties, manufacture and production, their chemistry, key properties, applications and their implications when used in the environment.

  12. Building synthetic memory

    PubMed Central

    Inniss, Mara C.; Silver, Pamela A.

    2013-01-01

    Synopsis Cellular memory – conversion of a transient signal into a sustained response – is a common feature of biological systems. Synthetic biologists aim to understand and reengineer such systems in a reliable and predictable manner. Synthetic memory circuits have been designed and built in vitro and in vivo based on diverse mechanisms such as oligonucleotide hybridization, recombination, transcription, phosphorylation, and RNA editing. Thus far, building these circuits has helped us explore the basic principles required for stable memory and ask novel biological questions. Here we discuss strategies for building synthetic memory circuits, their use as research tools, and future applications of these devices in medicine and industry. PMID:24028965

  13. Requiem for synthetic fuels

    SciTech Connect

    Myers, R.

    1982-01-27

    US plans to launch a synthetic fuels industry revive whenever a price or supply crisis occurs, but industrial hopes descend as soon as the short-term market begins improving in terms of real prices. The capital requirements of a synthetic fuels project combined with fears of a noncompetitive product have caused several major oil companies to scale down or cancel their plans. In the author's view, the Reagan administration's hands-off policy and false sense of security from the current oil supply glut have further discouraged industry. The Synthetic Fuels Corporation has been slow to organize, and appears to be favoring small-size plants. (DCK)

  14. Implantation in IVF.

    PubMed

    Busso, Cristiano E; Melo, Marco A B; Fernandez, Manuel; Pellicer, Antonio; Simon, Carlos

    2006-01-01

    The recent advances in assisted reproduction have made it possible to study and interfere in almost every step of the human reproductive process except for implantation. The most complex and important step remains in great part unknown. Implantation in human has proven to be less efficient compared with other species. However, in in vitro fertilization (IVF) patients, it has been evaluated to be even poorer. This paper highlights the factors related to infertile patients and IVF treatments that can affect implantation and implantation's clinical aspects related to these treatments: implantation failure and early pregnancy loss.

  15. What Are Synthetic Cannabinoids?

    MedlinePlus

    ... those produced by marijuana: elevated mood relaxation altered perception —awareness of surrounding objects and conditions symptoms of ... those produced by marijuana: elevated mood relaxation altered perception symptoms of psychosis Synthetic cannabinoids can also cause ...

  16. Analysis of Synthetic Polymers.

    ERIC Educational Resources Information Center

    Smith, Charles G.; And Others

    1989-01-01

    Reviews techniques for the characterization and analysis of synthetic polymers, copolymers, and blends. Includes techniques for structure determination, separation, and quantitation of additives and residual monomers; determination of molecular weight; and the study of thermal properties including degradation mechanisms. (MVL)

  17. Trends in Cochlear Implants

    PubMed Central

    Zeng, Fan-Gang

    2004-01-01

    More than 60,000 people worldwide use cochlear implants as a means to restore functional hearing. Although individual performance variability is still high, an average implant user can talk on the phone in a quiet environment. Cochlear-implant research has also matured as a field, as evidenced by the exponential growth in both the patient population and scientific publication. The present report examines current issues related to audiologic, clinical, engineering, anatomic, and physiologic aspects of cochlear implants, focusing on their psychophysical, speech, music, and cognitive performance. This report also forecasts clinical and research trends related to presurgical evaluation, fitting protocols, signal processing, and postsurgical rehabilitation in cochlear implants. Finally, a future landscape in amplification is presented that requires a unique, yet complementary, contribution from hearing aids, middle ear implants, and cochlear implants to achieve a total solution to the entire spectrum of hearing loss treatment and management. PMID:15247993

  18. Breast implants. A review.

    PubMed

    Van Zele, D; Heymans, O

    2004-04-01

    Breast implants have been used for about four decades for both reconstructive and aesthetic purposes. In 1963, the quality of the artificial implants was revolutionized by the introduction of the silicone gel-filled implant. Since, this modern prosthesis has gone through an evolution of change and improvement with several types of devices with many variations and styles within each class. Actually, for the last three decades, approximately one million women have received silicone breast implants in the USA. But, in 1992, the American FDA banned silicone from the market, leaving saline implants as the only product generally available as an alternative until now. Other filler materials were introduced, but have never progressed beyond the experimental stage in the USA (in contrast with Europe). The evolution of the different implants through time, with their advantages and disadvantages will be discussed, but also the controversy on silicone implants in the USA and their suspected association with systemic diseases. PMID:15154572

  19. Synthetic battery cycling techniques

    NASA Technical Reports Server (NTRS)

    Leibecki, H.; Thaller, L. H.

    1982-01-01

    The group of techniques that as a class are referred to as synthetic battery cycling are described with reference to spacecraft battery systems. Synthetic battery cycling makes use of the capability of computer graphics to illustrate some of the basic characteristics of operation of individual electrodes within an operating electrochemical cell. It can also simulate the operation of an entire string of cells that are used as the energy storage subsystem of a power system.

  20. Synthetic approaches to monofluoroalkenes.

    PubMed

    Landelle, Grégory; Bergeron, Maxime; Turcotte-Savard, Marc-Olivier; Paquin, Jean-François

    2011-05-01

    Monofluoroalkenes are an important fluorinated class of compounds with applications in medicinal chemistry, material sciences and organic chemistry. An overview of methods allowing synthetic access to these fluorinated building blocks is provided. In particular, this critical review, which covers publications up to October 2010, will be divided according to the substitution pattern of the monofluoroalkenes, i.e. di-, tri- or tetra-substituted. Within each group, the various synthetic approaches will be divided according to the reaction type (282 references).

  1. Active synthetic soil

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Henninger, Donald L. (Inventor); Allen, Earl R. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium and micronutrients dispersed in a calcium phosphate matrix, a zeolite cation exchange medium saturated with a charge of potassium and nitrogen cations, and an optional pH buffer. Moisture dissolves the apatite and mobilizes the nutrient elements from the apatite matrix and the zeolite charge sites.

  2. Active synthetic soil

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W. (Inventor); Henninger, Donald L. (Inventor); Allen, Earl R. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium, and micronutrients dispersed in a calcium phosphate matrix, a zeolite cation exchange medium saturated with a charge of potassium and nitrogen cations, and an optional pH buffer. Moisture dissolves the apatite and mobilizes the nutrient elements from the apatite matrix and the zeolite charge sites.

  3. Synthetic biology and biosecurity.

    PubMed

    Robienski, Jürgen; Simon, Jürgen

    2014-01-01

    This article discusses the conflict fields and legal questions of synthetic biology, esp. concerning biosecurity. A respective jurisprudential discussion has not taken place yet in Germany apart from few statements and recommendations. But in Germany, Europe and the USA, it is generally accepted that a broad discussion is necessary. This is esp. true for the question of biosecurity and the possible dangers arising from Synthetic Biology. PMID:25845204

  4. Synthetic Vision Systems

    NASA Technical Reports Server (NTRS)

    Prinzel, L.J.; Kramer, L.J.

    2009-01-01

    A synthetic vision system is an aircraft cockpit display technology that presents the visual environment external to the aircraft using computer-generated imagery in a manner analogous to how it would appear to the pilot if forward visibility were not restricted. The purpose of this chapter is to review the state of synthetic vision systems, and discuss selected human factors issues that should be considered when designing such displays.

  5. Communication Intervention for Children with Cochlear Implants: Two Case Studies.

    ERIC Educational Resources Information Center

    Ertmer, David J.; Leonard, Jeannette S.; Pachuilo, Michael L.

    2002-01-01

    This article describes the intervention programs attended and progress made by two children (ages 3 and 7) who exhibited considerable differences in benefit from their cochlear implants. Their intervention programs employed both analytical and synthetic auditory training and emphasized the development of speech production and language skills.…

  6. Safety considerations for synthetic sling surgery.

    PubMed

    Blaivas, Jerry G; Purohit, Rajveer S; Benedon, Matthew S; Mekel, Gabriel; Stern, Michael; Billah, Mubashir; Olugbade, Kola; Bendavid, Robert; Iakovlev, Vladimir

    2015-09-01

    Implantation of a synthetic midurethral sling (SMUS) is the most commonly performed anti-incontinence operation in women worldwide. The effectiveness of the SMUS is comparable to that of the historical gold standards--autologous fascial slings and the Burch colposuspension. Much controversy, however, has evolved regarding the safety of this type of sling. Overall, the quality of the studies with respect to assessing risks of SMUS-associated complications is currently poor. The most common risks in patients with SMUS include urethral obstruction requiring surgery (2.3% of patients with SMUS), vaginal, bladder and/or urethral erosion requiring surgery (1.8%) and refractory chronic pain (4.1%); these data likely represent the minimum risks. In addition, the failure rate of SMUS implantation surgery is probably at least 5% in patients with stress urinary incontinence (SUI). Furthermore, at least one-third of patients undergoing sling excision surgery develop recurrent SUI. Considering the additional risks of refractory overactive bladder, fistulas and bowel perforations, among others, the overall risk of a negative outcome after SMUS implantation surgery is ≥15%. PMID:26282209

  7. Nanotechnology and dental implants.

    PubMed

    Lavenus, Sandrine; Louarn, Guy; Layrolle, Pierre

    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 implants to bone rather than fibrous tissue encapsulation. Surfaces properties such as chemistry and roughness play a determinant role in these biological interactions. Physicochemical features in the nanometer range may ultimately control the adsorption of proteins as well as the adhesion and differentiation of cells. Nanotechnologies are increasingly used for surface modifications of dental implants. Another approach to enhance osseointegration is the application of thin calcium phosphate (CaP) coatings. Bioactive CaP nanocrystals deposited on titanium implants are resorbable and stimulate bone apposition and healing. Future nanometer-controlled surfaces may ultimately direct the nature of peri-implant tissues and improve their clinical success rate.

  8. Nanotechnology and Dental Implants

    PubMed Central

    Lavenus, Sandrine; Louarn, Guy; Layrolle, Pierre

    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 implants to bone rather than fibrous tissue encapsulation. Surfaces properties such as chemistry and roughness play a determinant role in these biological interactions. Physicochemical features in the nanometer range may ultimately control the adsorption of proteins as well as the adhesion and differentiation of cells. Nanotechnologies are increasingly used for surface modifications of dental implants. Another approach to enhance osseointegration is the application of thin calcium phosphate (CaP) coatings. Bioactive CaP nanocrystals deposited on titanium implants are resorbable and stimulate bone apposition and healing. Future nanometer-controlled surfaces may ultimately direct the nature of peri-implant tissues and improve their clinical success rate. PMID:21253543

  9. Differential Synthetic Aperture Ladar

    SciTech Connect

    Stappaerts, E A; Scharlemann, E

    2005-02-07

    We report a differential synthetic aperture ladar (DSAL) concept that relaxes platform and laser requirements compared to conventional SAL. Line-of-sight translation/vibration constraints are reduced by several orders of magnitude, while laser frequency stability is typically relaxed by an order of magnitude. The technique is most advantageous for shorter laser wavelengths, ultraviolet to mid-infrared. Analytical and modeling results, including the effect of speckle and atmospheric turbulence, are presented. Synthetic aperture ladars are of growing interest, and several theoretical and experimental papers have been published on the subject. Compared to RF synthetic aperture radar (SAR), platform/ladar motion and transmitter bandwidth constraints are especially demanding at optical wavelengths. For mid-IR and shorter wavelengths, deviations from a linear trajectory along the synthetic aperture length have to be submicron, or their magnitude must be measured to that precision for compensation. The laser coherence time has to be the synthetic aperture transit time, or transmitter phase has to be recorded and a correction applied on detection.

  10. Implants in adolescents

    PubMed Central

    Shah, Rohit A.; Mitra, Dipika K.; Rodrigues, Silvia V.; Pathare, Pragalbha N.; Podar, Rajesh S.; Vijayakar, Harshad N.

    2013-01-01

    Implants have gained tremendous popularity as a treatment modality for replacement of missing teeth in adults. There is extensive research present on the use of implants in adults, but there is a dearth of data available on the same in adolescents. The treatment planning and execution of implant placement in adolescents is still in its infancy. This review article is an attempt to bring together available literature. PMID:24174743

  11. Implantable cardioverter defibrillator - discharge

    MedlinePlus

    Baddour LM, Epstein AE, Erickson CC, et al. Update on cardiovascular implantable electronic device infections and their management: a scientific statement from the American Heart Association. Circulation . ...

  12. Synthetic battery cycling techniques

    NASA Technical Reports Server (NTRS)

    Leibecki, H. F.; Thaller, L. H.

    1982-01-01

    Synthetic battery cycling makes use of the fast growing capability of computer graphics to illustrate some of the basic characteristics of operation of individual electrodes within an operating electrochemical cell. It can also simulate the operation of an entire string of cells that are used as the energy storage subsystem of a power system. The group of techniques that as a class have been referred to as Synthetic Battery Cycling is developed in part to try to bridge the gap of understanding that exists between single cell characteristics and battery system behavior.

  13. Synthetic guide star generation

    DOEpatents

    Payne, Stephen A.; Page, Ralph H.; Ebbers, Christopher A.; Beach, Raymond J.

    2004-03-09

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  14. Synthetic guide star generation

    DOEpatents

    Payne, Stephen A [Castro Valley, CA; Page, Ralph H [Castro Valley, CA; Ebbers, Christopher A [Livermore, CA; Beach, Raymond J [Livermore, CA

    2008-06-10

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  15. Bio-packaged transponder MEMS implanted in rats.

    PubMed

    Rodriguez, R; Loske, A M; Estevez, M; Vargas, S; Salazar, R; Pacheco, F; Vazquez-Carpizo, J; Gamboa, J M

    2013-01-01

    A novel hydroxyapatite-based hybrid material with controlled porosity was designed as a bio-package to implant micro-electro-mechanical systems (MEMS) in living organisms. The biomaterial was prepared using synthetic stoichiometric hydroxyapatite powder reacted with a chemical-active, solvent-free, alkyd-based polyurethane. This porous material has interconnected pores with sizes between 100 and 350 μm and a pore volume fraction of 50%, fulfilling the requirements for implants. The biomaterial additionally has high wearing resistance and hydrolytic stability providing high endurance properties. The bio-package was characterized mechanically and morphologically using X-ray diffraction, scanning electron microscopy, densitometry, abrasion and mechanical tests. Twelve packaged micro-electro-mechanical systems were implanted subcutaneously into rats and tested for up to 9 months with good acceptance as revealed by the histological analysis performed on the soft tissue surrounding each implant.

  16. Synthetic Visibility System

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Test pilot Lee Person evaluates a Synthetic Visibility System - in essence, two helmet-mounted eyepieces connected to video cameras that swivel in response to head movements. Photograph published in Winds of Change, 75th Anniversary NASA publication (page 113), by James Schultz.

  17. Adaptive synthetic vision

    NASA Astrophysics Data System (ADS)

    Julier, Simon J.; Brown, Dennis; Livingston, Mark A.; Thomas, Justin

    2006-05-01

    Through their ability to safely collect video and imagery from remote and potentially dangerous locations, UAVs have already transformed the battlespace. The effectiveness of this information can be greatly enhanced through synthetic vision. Given knowledge of the extrinsic and intrinsic parameters of the camera, synthetic vision superimposes spatially-registered computer graphics over the video feed from the UAV. This technique can be used to show many types of data such as landmarks, air corridors, and the locations of friendly and enemy forces. However, the effectiveness of a synthetic vision system strongly depends on the accuracy of the registration - if the graphics are poorly aligned with the real world they can be confusing, annoying, and even misleading. In this paper, we describe an adaptive approach to synthetic vision that modifies the way in which information is displayed depending upon the registration error. We describe an integrated software architecture that has two main components. The first component automatically calculates registration error based on information about the uncertainty in the camera parameters. The second component uses this information to modify, aggregate, and label annotations to make their interpretation as clear as possible. We demonstrate the use of this approach on some sample datasets.

  18. Synthetic Aperture Radar Interferometry

    NASA Technical Reports Server (NTRS)

    Rosen, P. A.; Hensley, S.; Joughin, I. R.; Li, F.; Madsen, S. N.; Rodriguez, E.; Goldstein, R. M.

    1998-01-01

    Synthetic aperture radar interferometry is an imaging technique for measuring the topography of a surface, its changes over time, and other changes in the detailed characteristics of the surface. This paper reviews the techniques of interferometry, systems and limitations, and applications in a rapidly growing area of science and engineering.

  19. Towards a Synthetic Chloroplast

    PubMed Central

    Agapakis, Christina M.; Niederholtmeyer, Henrike; Noche, Ramil R.; Lieberman, Tami D.; Megason, Sean G.; Way, Jeffrey C.; Silver, Pamela A.

    2011-01-01

    Background The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner. Results We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages. Conclusion Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices. PMID:21533097

  20. Biodegradable synthetic bone composites

    DOEpatents

    Liu, Gao; Zhao, Dacheng; Saiz, Eduardo; Tomsia, Antoni P.

    2013-01-01

    The invention provides for a biodegradable synthetic bone composition comprising a biodegradable hydrogel polymer scaffold comprising a plurality of hydrolytically unstable linkages, and an inorganic component; such as a biodegradable poly(hydroxyethylmethacrylate)/hydroxyapatite (pHEMA/HA) hydrogel composite possessing mineral content approximately that of human bone.

  1. Synthetic Bursae for Robots

    NASA Technical Reports Server (NTRS)

    Lovchik, Christopher S.

    2005-01-01

    Synthetic bursae are under development for incorporation into robot joints that are actuated by motor-driven cables in a manner similar to that of arthropod joints actuated by muscle-driven tendons. Like natural bursae, the synthetic bursae would serve as cushions and friction reducers. A natural bursa is a thin bladder filled with synovial fluid, which serves to reduce friction and provide a cushion between a bone and a muscle or a tendon. A synthetic bursa would be similar in form and function: It would be, essentially, a compact, soft roller consisting of a bladder filled with a non-Newtonian fluid. The bladder would be constrained to approximately constant volume. The synthetic bursa would cushion an actuator cable against one of the members of a robot joint and would reduce the friction between the cable and the member. Under load, the pressure in the bladder would hold the opposite walls of the bladder apart, making it possible for them to move freely past each other without rubbing.

  2. Synthetic Confrontation Therapy.

    ERIC Educational Resources Information Center

    Gilliam, Larry

    After initially dispelling predictable fears that his paper might suggest that computers can be equated with man, the author states the problem: what part, if any, might computers play in counseling. Specifically, the possibilities for therapeutic synthetic (artificial) counseling encounters are discussed. Two propositions are significant: (1) the…

  3. Synthetic Vision Workshop 2

    NASA Technical Reports Server (NTRS)

    Kramer, Lynda J. (Compiler)

    1999-01-01

    The second NASA sponsored Workshop on Synthetic/Enhanced Vision (S/EV) Display Systems was conducted January 27-29, 1998 at the NASA Langley Research Center. The purpose of this workshop was to provide a forum for interested parties to discuss topics in the Synthetic Vision (SV) element of the NASA Aviation Safety Program and to encourage those interested parties to participate in the development, prototyping, and implementation of S/EV systems that enhance aviation safety. The SV element addresses the potential safety benefits of synthetic/enhanced vision display systems for low-end general aviation aircraft, high-end general aviation aircraft (business jets), and commercial transports. Attendance at this workshop consisted of about 112 persons including representatives from industry, the FAA, and other government organizations (NOAA, NIMA, etc.). The workshop provided opportunities for interested individuals to give presentations on the state of the art in potentially applicable systems, as well as to discuss areas of research that might be considered for inclusion within the Synthetic Vision Element program to contribute to the reduction of the fatal aircraft accident rate. Panel discussions on topical areas such as databases, displays, certification issues, and sensors were conducted, with time allowed for audience participation.

  4. Synthetic plant defense elicitors

    PubMed Central

    Bektas, Yasemin; Eulgem, Thomas

    2015-01-01

    To defend themselves against invading pathogens plants utilize a complex regulatory network that coordinates extensive transcriptional and metabolic reprogramming. Although many of the key players of this immunity-associated network are known, the details of its topology and dynamics are still poorly understood. As an alternative to forward and reverse genetic studies, chemical genetics-related approaches based on bioactive small molecules have gained substantial popularity in the analysis of biological pathways and networks. Use of such molecular probes can allow researchers to access biological space that was previously inaccessible to genetic analyses due to gene redundancy or lethality of mutations. Synthetic elicitors are small drug-like molecules that induce plant defense responses, but are distinct from known natural elicitors of plant immunity. While the discovery of some synthetic elicitors had already been reported in the 1970s, recent breakthroughs in combinatorial chemical synthesis now allow for inexpensive high-throughput screens for bioactive plant defense-inducing compounds. Along with powerful reverse genetics tools and resources available for model plants and crop systems, comprehensive collections of new synthetic elicitors will likely allow plant scientists to study the intricacies of plant defense signaling pathways and networks in an unparalleled fashion. As synthetic elicitors can protect crops from diseases, without the need to be directly toxic for pathogenic organisms, they may also serve as promising alternatives to conventional biocidal pesticides, which often are harmful for the environment, farmers and consumers. Here we are discussing various types of synthetic elicitors that have been used for studies on the plant immune system, their modes-of-action as well as their application in crop protection. PMID:25674095

  5. Synthetic River Valleys

    NASA Astrophysics Data System (ADS)

    Brown, R.; Pasternack, G. B.

    2011-12-01

    The description of fluvial form has evolved from anecdotal descriptions to artistic renderings to 2D plots of cross section or longitudinal profiles and more recently 3D digital models. Synthetic river valleys, artificial 3D topographic models of river topography, have a plethora of potential applications in fluvial geomorphology, and the earth sciences in general, as well as in computer science and ecology. Synthetic river channels have existed implicitly since approximately the 1970s and can be simulated from a variety of approaches spanning the artistic and numerical. An objective method of synthesizing 3D stream topography based on reach scale attributes would be valuable for sizing 3D flumes in the physical and numerical realms, as initial input topography for morphodynamic models, stream restoration design, historical reconstruction, and mechanistic testing of interactions of channel geometric elements. Quite simply - simulation of synthetic channel geometry of prescribed conditions can allow systematic evaluation of the dominant relationships between river flow and geometry. A new model, the control curve method, is presented that uses hierarchically scaled parametric curves in over-lapping 2D planes to create synthetic river valleys. The approach is able to simulate 3D stream geometry from paired 2D descriptions and can allow experimental insight into form-process relationships in addition to visualizing past measurements of channel form that are limited to two dimension descriptions. Results are presented that illustrate the models ability to simulate fluvial topography representative of real world rivers as well as how channel geometric elements can be adjusted. The testing of synthetic river valleys would open up a wealth of knowledge as to why some 3D attributes of river channels are more prevalent than others as well as bridging the gap between the 2D descriptions that have dominated fluvial geomorphology the past century and modern, more complete, 3D

  6. Batteryless implanted echosonometer

    NASA Technical Reports Server (NTRS)

    Kojima, G. K.

    1977-01-01

    Miniature ultrasonic echosonometer implanted within laboratory animals obtains energy from RF power oscillator that is electronically transduced via induction loop to power receiving loop located just under animal's skin. Method of powering device offers significant advantages over those in which battery is part of implanted package.

  7. Implantable, Ingestible Electronic Thermometer

    NASA Technical Reports Server (NTRS)

    Kleinberg, Leonard

    1987-01-01

    Small quartz-crystal-controlled oscillator swallowed or surgically implanted provides continuous monitoring of patient's internal temperature. Receiver placed near patient measures oscillator frequency, and temperature inferred from previously determined variation of frequency with temperature. Frequency of crystal-controlled oscillator varies with temperature. Circuit made very small and implanted or ingested to measure internal body temperature.

  8. Graphene for Biomedical Implants

    NASA Astrophysics Data System (ADS)

    Moore, Thomas; Podila, Ramakrishna; Alexis, Frank; Rao, Apparao; Clemson Bioengineering Team; Clemson Physics Team

    2013-03-01

    In this study, we used graphene, a one-atom thick sheet of carbon atoms, to modify the surfaces of existing implant materials to enhance both bio- and hemo-compatibility. This novel effort meets all functional criteria for a biomedical implant coating as it is chemically inert, atomically smooth and highly durable, with the potential for greatly enhancing the effectiveness of such implants. Specifically, graphene coatings on nitinol, a widely used implant and stent material, showed that graphene coated nitinol (Gr-NiTi) supports excellent smooth muscle and endothelial cell growth leading to better cell proliferation. We further determined that the serum albumin adsorption on Gr-NiTi is greater than that of fibrinogen, an important and well understood criterion for promoting a lower thrombosis rate. These hemo-and biocompatible properties and associated charge transfer mechanisms, along with high strength, chemical inertness and durability give graphene an edge over most antithrombogenic coatings for biomedical implants and devices.

  9. Mesh implants: An overview of crucial mesh parameters

    PubMed Central

    Zhu, Lei-Ming; Schuster, Philipp; Klinge, Uwe

    2015-01-01

    Hernia repair is one of the most frequently performed surgical interventions that use mesh implants. This article evaluates crucial mesh parameters to facilitate selection of the most appropriate mesh implant, considering raw materials, mesh composition, structure parameters and mechanical parameters. A literature review was performed using the PubMed database. The most important mesh parameters in the selection of a mesh implant are the raw material, structural parameters and mechanical parameters, which should match the physiological conditions. The structural parameters, especially the porosity, are the most important predictors of the biocompatibility performance of synthetic meshes. Meshes with large pores exhibit less inflammatory infiltrate, connective tissue and scar bridging, which allows increased soft tissue ingrowth. The raw material and combination of raw materials of the used mesh, including potential coatings and textile design, strongly impact the inflammatory reaction to the mesh. Synthetic meshes made from innovative polymers combined with surface coating have been demonstrated to exhibit advantageous behavior in specialized fields. Monofilament, large-pore synthetic meshes exhibit advantages. The value of mesh classification based on mesh weight seems to be overestimated. Mechanical properties of meshes, such as anisotropy/isotropy, elasticity and tensile strength, are crucial parameters for predicting mesh performance after implantation. PMID:26523210

  10. Nanoparticles as synthetic vaccines.

    PubMed

    Smith, Josiah D; Morton, Logan D; Ulery, Bret D

    2015-08-01

    As vaccines have transitioned from the use of whole pathogens to only the required antigenic epitopes, unwanted side effects have been decreased, but corresponding immune responses have been greatly diminished. To enhance immunogenicity, a variety of controlled release vehicles have been proposed as synthetic vaccines, but nanoparticles have emerged as particularly impressive systems due to many exciting publications. In specific, nanoparticles have been shown capable of not only desirable vaccine release, but can also be targeted to immune cells of interest, loaded with immunostimulatory substances termed adjuvants, or even induce desirable immune activating effects on their own. In the present review, recent advances in the utilization of inorganic, polymeric, and biomolecular nanoparticles as synthetic vaccines are discussed.

  11. Synthetic Foveal Imaging Technology

    NASA Technical Reports Server (NTRS)

    Monacos, Steve P. (Inventor); Hoenk, Michael E. (Inventor); Nikzad, Shouleh (Inventor)

    2013-01-01

    Apparatuses and methods are disclosed that create a synthetic fovea in order to identify and highlight interesting portions of an image for further processing and rapid response. Synthetic foveal imaging implements a parallel processing architecture that uses reprogrammable logic to implement embedded, distributed, real-time foveal image processing from different sensor types while simultaneously allowing for lossless storage and retrieval of raw image data. Real-time, distributed, adaptive processing of multi-tap image sensors with coordinated processing hardware used for each output tap is enabled. In mosaic focal planes, a parallel-processing network can be implemented that treats the mosaic focal plane as a single ensemble rather than a set of isolated sensors. Various applications are enabled for imaging and robotic vision where processing and responding to enormous amounts of data quickly and efficiently is important.

  12. Wholly Synthetic Molecular Machines.

    PubMed

    Cheng, Chuyang; Stoddart, J Fraser

    2016-06-17

    The past quarter of a century has witnessed an increasing engagement on the part of physicists and chemists in the design and synthesis of molecular machines de novo. This minireview traces the development of artificial molecular machines from their prototypes in the form of shuttles and switches to their emergence as motors and pumps where supplies of energy in the form of chemical fuel, electrochemical potential and light activation become a minimum requirement for them to function away from equilibrium. The challenge facing this rapidly growing community of scientists and engineers today is one of putting wholly synthetic molecules to work, both individually and as collections. Here, we highlight some of the recent conceptual and practical advances relating to the operation of wholly synthetic rotary and linear motors.

  13. Engineered Asymmetric Synthetic Vesicles

    NASA Astrophysics Data System (ADS)

    Lu, Li; Chiarot, Paul

    2013-11-01

    Synthetic vesicles are small, fluid-filled spheres that are enclosed by a bilayer of lipid molecules. They can be used as models for investigating membrane biology and as delivery vehicles for pharmaceuticals. In practice, it is difficult to simultaneously control membrane asymmetry, unilamellarity, vesicle size, vesicle-to-vesicle uniformity, and luminal content. Membrane asymmetry, where each leaflet of the bilayer is composed of different lipids, is of particular importance as it is a feature of most natural membranes. In this study, we leverage microfluidic technology to build asymmetric vesicles at high-throughput. We use the precise flow control offered by microfluidic devices to make highly uniform emulsions, with controlled internal content, that serve as templates to build the synthetic vesicles. Flow focusing, dielectrophoretic steering, and interfacial lipid self-assembly are critical procedures performed on-chip to produce the vesicles. Fluorescent and confocal microscopy are used to evaluate the vesicle characteristics.

  14. EXPEDITIOUS SYNTHETIC TRANSFORMATIONS USING MICROWAVES

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes will be described for the synthesis of a variety of industrially significant compounds and intermediates namely, enamines, nitroalkenes, enones, oxidized sulfur compounds and ionic liquids. This solvent-free synthetic methodolo...

  15. Dental Implant Systems

    PubMed Central

    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

  16. Chemical synthetic biology.

    PubMed

    Chiarabelli, Cristiano; Luisi, Pier Luigi

    2014-01-01

    Although both the most popular form of synthetic biology (SB) and chemical synthetic biology (CSB) share the biotechnologically useful aim of making new forms of life, SB does so by using genetic manipulation of extant microorganism, while CSB utilises classic chemical procedures in order to obtain biological structures which are non-existent in nature. The main query concerning CSB is the philosophical question: why did nature do this, and not that? The idea then is to synthesise alternative structures in order to understand why nature operated in such a particular way. We briefly present here some various examples of CSB, including those cases of nucleic acids synthesised with pyranose instead of ribose, and proteins with a reduced alphabet of amino acids; also we report the developing research on the "never born proteins" (NBP) and "never born RNA" (NBRNA), up to the minimal cell project, where the issue is the preparation of semi-synthetic cells that can perform the basic functions of biological cells.

  17. Optical synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Ilovitsh, Asaf; Zach, Shlomo; Zalevsky, Zeev

    2013-06-01

    A method is proposed for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving imaging system, such as an airborne platform or satellite. The resolution improvement is obtained via a two-step process. First, three low resolution differently defocused images are captured and the optical phase is retrieved using an improved iterative Gershberg-Saxton based algorithm. The phase retrieval allows numerical back propagation of the field to the aperture plane. Second, the imaging system is shifted and the first step is repeated. The obtained optical fields at the aperture plane are combined and a synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution. The method resembles a well-known approach from the microwave regime called the synthetic aperture radar in which the antenna size is synthetically increased along the platform propagation direction. The proposed method is demonstrated via Matlab simulation as well as through laboratory experiment.

  18. Synthetic surgical gloves.

    PubMed

    2002-06-01

    Surgical gloves are used by healthcare workers to protect them against bloodborne pathogens and other potential infectants and to prevent wound contamination in patients. In response to the increasing prevalence of allergies to natural rubber latex (NRL) among patients and medical staff, the trend toward purchasing gloves made of synthetic materials is on the rise. However, latex continues to dominate the market, and some people still perceive synthetic gloves as providing less protection and being less comfortable than NRL gloves. For this Update Evaluation, we present our findings for three newly evaluated glove models from three manufacturers and summarize our findings for the seven previously evaluated models that are still on the market. (Our earlier Evaluation was published in the February-March 2000 Health Devices.) As in the previous Evaluation, our ratings are based on the gloves' barrier effectiveness--that is, their resistance to viral penetration and their durability--and comfort. We also compared these characteristics of the synthetic gloves to those of NRL gloves. We found that all the evaluated gloves offer adequate barrier protection but that their level of comfort varies considerably. We rate three models Preferred, five models Acceptable, and two models Not Recommended. PMID:12116503

  19. Synthetic biology in plastids.

    PubMed

    Scharff, Lars B; Bock, Ralph

    2014-06-01

    Plastids (chloroplasts) harbor a small gene-dense genome that is amenable to genetic manipulation by transformation. During 1 billion years of evolution from the cyanobacterial endosymbiont to present-day chloroplasts, the plastid genome has undergone a dramatic size reduction, mainly as a result of gene losses and the large-scale transfer of genes to the nuclear genome. Thus the plastid genome can be regarded as a naturally evolved miniature genome, the gradual size reduction and compaction of which has provided a blueprint for the design of minimum genomes. Furthermore, because of the largely prokaryotic genome structure and gene expression machinery, the high transgene expression levels attainable in transgenic chloroplasts and the very low production costs in plant systems, the chloroplast lends itself to synthetic biology applications that are directed towards the efficient synthesis of green chemicals, biopharmaceuticals and other metabolites of commercial interest. This review describes recent progress with the engineering of plastid genomes with large constructs of foreign or synthetic DNA, and highlights the potential of the chloroplast as a model system in bottom-up and top-down synthetic biology approaches.

  20. Mobility implants: a review.

    PubMed

    Danz, W

    1990-01-01

    We present a brief review of mobility implants, their contribution, and the experiences derived after almost 40 years since the new concepts of full mobility implants were introduced. In early 1940, experiments with a new material for the making of plastic artificial eyes was also being considered for the making of orbital implants. Methyl-methacrylate (MMA) had proven inert and satisfactory for dental products. The Surgeon Generals office of the Armed Services encouraged further research and experimental work in the development of plastic eyes. The success of the new material sponsored the beginning of great expansion with new concepts for orbital implants. Through a period of more than a decade, the design and types of implants went through three stages. First, the buried implant was introduced, then the exposed integrated followed, and the buried integrated subsequently followed. The path of progress was not smooth. Theoretically correct designs and surgical procedures met unexpected practical difficulties for the ophthalmic surgeon, the patient, and the eye maker. Surgical and technical efforts were carefully reviewed to eliminate the problems encountered, only to have further unforeseen complications arise. Infections, extrusions, and migration of the implant were not uncommon. The exposed integrated implant was eventually abandoned. However, there were some extraordinary successes of mobility. A new era introduced fully buried mobility implants that were more successful. However, this procedure also produced some problems, causing infection (or allergy), extrusion, and migration. Tantalum mesh and gauze gave great promise with the inception of their use. Orbital tissue grew into the material in an astonishing way, making it possible to secure the extraocular muscles and tenons.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Nanotechnology for dental implants.

    PubMed

    Tomsia, Antoni P; Lee, Janice S; Wegst, Ulrike G K; Saiz, Eduardo

    2013-01-01

    With the advent of nanotechnology, an opportunity exists for the engineering of new dental implant materials. Metallic dental implants have been successfully used for decades, but they have shortcomings related to osseointegration and mechanical properties that do not match those of bone. Absent the development of an entirely new class of materials, faster osseointegration of currently available dental implants can be accomplished by various surface modifications. To date, there is no consensus regarding the preferred method(s) of implant surface modification, and further development will be required before the ideal implant surface can be created, let alone become available for clinical use. Current approaches can generally be categorized into three areas: ceramic coatings, surface functionalization, and patterning on the micro- to nanoscale. The distinctions among these are imprecise, as some or all of these approaches can be combined to improve in vivo implant performance. These surface improvements have resulted in durable implants with a high percentage of success and long-term function. Nanotechnology has provided another set of opportunities for the manipulation of implant surfaces in its capacity to mimic the surface topography formed by extracellular matrix components of natural tissue. The possibilities introduced by nanotechnology now permit the tailoring of implant chemistry and structure with an unprecedented degree of control. For the first time, tools are available that can be used to manipulate the physicochemical environment and monitor key cellular events at the molecular level. These new tools and capabilities will result in faster bone formation, reduced healing time, and rapid recovery to function.

  2. Reflections on Rodent Implantation.

    PubMed

    Cha, Jeeyeon M; Dey, Sudhansu K

    2015-01-01

    Embryo implantation is a complex process involving endocrine, paracrine, autocrine, and juxtacrine modulators that span cell-cell and cell-matrix interactions. The quality of implantation is predictive for pregnancy success. Earlier observational studies formed the basis for genetic and molecular approaches that ensued with emerging technological advances. However, the precise sequence and details of the molecular interactions involved have yet to be defined. This review reflects briefly on aspects of our current understanding of rodent implantation as a tribute to Roger Short's lifelong contributions to the field of reproductive physiology. PMID:26450495

  3. Spectroscopy of implants

    NASA Astrophysics Data System (ADS)

    Afanasyeva, Natalia I.

    1994-01-01

    The spectral criteria of selection of soft intraocular lens (IOL) implants of long service in an organism have been defined for ophthalmology. The analysis of Fourier Transform Infrared (FTIR) spectra provides the required and sufficient level of material polymerization for manufacturing non-toxic lenses for the eye. The spectral limits for determining the biocompatibility of samples can be related to the intensity ratio of two bands only in the FTIR spectra of siloxane. Siloxane-poly(urethane) block copolymers and other materials for implants have been studied. Passivated surfaces of implants have been obtained and registered by methods of Fourier Transform Spectroscopy.

  4. The evolution of embryo implantation.

    PubMed

    McGowen, Michael R; Erez, Offer; Romero, Roberto; Wildman, Derek E

    2014-01-01

    Embryo implantation varies widely in placental mammals. We review this variation in mammals with a special focus on two features: the depth of implantation and embryonic diapause. We discuss the two major types of implantation depth, superficial and interstitial, and map this character on a well-resolved molecular phylogenetic tree of placental mammals. We infer that relatively deep interstitial implantation has independently evolved at least eight times within placental mammals. Moreover, the superficial type of implantation represents the ancestral state for placental mammals. In addition, we review the genes involved in various phases of implantation, and suggest a future direction in investigating the molecular evolution of implantation-related genes. PMID:25023681

  5. Opportunities in plant synthetic biology.

    PubMed

    Cook, Charis; Martin, Lisa; Bastow, Ruth

    2014-05-01

    Synthetic biology is an emerging field uniting scientists from all disciplines with the aim of designing or re-designing biological processes. Initially, synthetic biology breakthroughs came from microbiology, chemistry, physics, computer science, materials science, mathematics, and engineering disciplines. A transition to multicellular systems is the next logical step for synthetic biologists and plants will provide an ideal platform for this new phase of research. This meeting report highlights some of the exciting plant synthetic biology projects, and tools and resources, presented and discussed at the 2013 GARNet workshop on plant synthetic biology.

  6. Opportunities in plant synthetic biology.

    PubMed

    Cook, Charis; Martin, Lisa; Bastow, Ruth

    2014-05-01

    Synthetic biology is an emerging field uniting scientists from all disciplines with the aim of designing or re-designing biological processes. Initially, synthetic biology breakthroughs came from microbiology, chemistry, physics, computer science, materials science, mathematics, and engineering disciplines. A transition to multicellular systems is the next logical step for synthetic biologists and plants will provide an ideal platform for this new phase of research. This meeting report highlights some of the exciting plant synthetic biology projects, and tools and resources, presented and discussed at the 2013 GARNet workshop on plant synthetic biology. PMID:24502956

  7. Peri-Implant Diseases

    MedlinePlus

    ... and flossing and regular check-ups from a dental professional. Other risks factors for developing peri-implant disease include previous periodontal disease diagnosis, poor plaque control, smoking , and diabetes . It is essential to routinely ...

  8. Superelastic Orthopedic Implant Coatings

    NASA Astrophysics Data System (ADS)

    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.

  9. Risks of Breast Implants

    MedlinePlus

    ... larger and longer than these conducted so far. Breastfeeding Some women who undergo breast augmentation can successfully ... breast implant silicone shell into breast milk during breastfeeding. Although there are currently no established methods for ...

  10. Ion implantation at elevated temperatures

    SciTech Connect

    Lam, N.Q.; Leaf, G.K.

    1985-11-01

    A kinetic model has been developed to investigate the synergistic effects of radiation-enhanced diffusion, radiation-induced segregation and preferential sputtering on the spatial redistribution of implanted solutes during implantation at elevated temperatures. Sample calculations were performed for Al and Si ions implanted into Ni. With the present model, the influence of various implantation parameters on the evolution of implant concentration profiles could be examined in detail.

  11. Implant treatment planning: endodontic considerations.

    PubMed

    Simonian, Krikor; Frydman, Alon; Verdugo, Fernando; Roges, Rafael; Kar, Kian

    2014-12-01

    Implants are a predictable and effective method for replacing missing teeth. Some clinicians have advocated extraction and replacement of compromised but treatable teeth on the assumption that implants will outperform endodontically and/or periodontally treated teeth. However, evidence shows that conventional therapy is as effective as implant treatment. With data on implants developing complications long term and a lack of predictable treatment for peri-implantitis, retaining and restoring the natural dentition should be the first choice when possible. PMID:25928961

  12. Medical Textiles as Vascular Implants and Their Success to Mimic Natural Arteries.

    PubMed

    Singh, Charanpreet; Wong, Cynthia S; Wang, Xungai

    2015-06-30

    Vascular implants belong to a specialised class of medical textiles. The basic purpose of a vascular implant (graft and stent) is to act as an artificial conduit or substitute for a diseased artery. However, the long-term healing function depends on its ability to mimic the mechanical and biological behaviour of the artery. This requires a thorough understanding of the structure and function of an artery, which can then be translated into a synthetic structure based on the capabilities of the manufacturing method utilised. Common textile manufacturing techniques, such as weaving, knitting, braiding, and electrospinning, are frequently used to design vascular implants for research and commercial purposes for the past decades. However, the ability to match attributes of a vascular substitute to those of a native artery still remains a challenge. The synthetic implants have been found to cause disturbance in biological, biomechanical, and hemodynamic parameters at the implant site, which has been widely attributed to their structural design. In this work, we reviewed the design aspect of textile vascular implants and compared them to the structure of a natural artery as a basis for assessing the level of success as an implant. The outcome of this work is expected to encourage future design strategies for developing improved long lasting vascular implants.

  13. Medical Textiles as Vascular Implants and Their Success to Mimic Natural Arteries

    PubMed Central

    Singh, Charanpreet; Wong, Cynthia S.; Wang, Xungai

    2015-01-01

    Vascular implants belong to a specialised class of medical textiles. The basic purpose of a vascular implant (graft and stent) is to act as an artificial conduit or substitute for a diseased artery. However, the long-term healing function depends on its ability to mimic the mechanical and biological behaviour of the artery. This requires a thorough understanding of the structure and function of an artery, which can then be translated into a synthetic structure based on the capabilities of the manufacturing method utilised. Common textile manufacturing techniques, such as weaving, knitting, braiding, and electrospinning, are frequently used to design vascular implants for research and commercial purposes for the past decades. However, the ability to match attributes of a vascular substitute to those of a native artery still remains a challenge. The synthetic implants have been found to cause disturbance in biological, biomechanical, and hemodynamic parameters at the implant site, which has been widely attributed to their structural design. In this work, we reviewed the design aspect of textile vascular implants and compared them to the structure of a natural artery as a basis for assessing the level of success as an implant. The outcome of this work is expected to encourage future design strategies for developing improved long lasting vascular implants. PMID:26133386

  14. Biomaterials in cochlear implants

    PubMed Central

    Stöver, Timo; Lenarz, Thomas

    2011-01-01

    The cochlear implant (CI) represents, for almost 25 years now, the gold standard in the treatment of children born deaf and for postlingually deafened adults. These devices thus constitute the greatest success story in the field of ‘neurobionic’ prostheses. Their (now routine) fitting in adults, and especially in young children and even babies, places exacting demands on these implants, particularly with regard to the biocompatibility of a CI’s surface components. Furthermore, certain parts of the implant face considerable mechanical challenges, such as the need for the electrode array to be flexible and resistant to breakage, and for the implant casing to be able to withstand external forces. As these implants are in the immediate vicinity of the middle-ear mucosa and of the junction to the perilymph of the cochlea, the risk exists – at least in principle – that bacteria may spread along the electrode array into the cochlea. The wide-ranging requirements made of the CI in terms of biocompatibility and the electrode mechanism mean that there is still further scope – despite the fact that CIs are already technically highly sophisticated – for ongoing improvements to the properties of these implants and their constituent materials, thus enhancing the effectiveness of these devices. This paper will therefore discuss fundamental material aspects of CIs as well as the potential for their future development. PMID:22073103

  15. Simple Implant Augmentation Rhinoplasty.

    PubMed

    Nguyen, Anh H; Bartlett, Erica L; Kania, Katarzyna; Bae, Sang Mo

    2015-11-01

    Augmentation rhinoplasty among Asian patients is often performed to improve the height of the nasal dorsum. As the use of autogenous tissues poses certain limitations, alloplastic materials are a viable alternative with a long history of use in Asia. The superiority of one implant prosthesis over another for augmentation rhinoplasty is a matter of debate, with each material representing varying strengths and weaknesses, indications for use, and precautions to consider in nasal implant placement. An implant prosthesis should be used on a case-by-case basis. Augmentation rhinoplasty requires the consideration of specific anatomical preoperative factors, including the external nose, nasal length, nasofrontal angle, humps, and facial proportions. It is equally important to consider several operative guidelines to appropriately shape implants to minimize the occurrence of adverse effects and postoperative complications. The most common postoperative complications include infection, nasal height change, movement of implant prosthesis, and silicone implant protrusion. In addition, the surgeon should consider the current standards of Asian beauty aesthetics to better understand the patient's desired outcome. PMID:26648804

  16. Dexamethasone: intravitreal implant.

    PubMed

    2011-01-01

    Macular oedema is one of the complications of retinal vein occlusion. About half of the patients recover spontaneously within 3 to 6 months. There is currently no drug that improves outcome. An intravitreal implant delivering 0.7 mg of dexamethasone has been authorised for the treatment of macular oedema in this setting. Clinical assessment is based on two double-blind randomised trials including a total of 1267 patients, comparing treatment with intravitreal implants delivering about 0.7 mg or 0.35 mg of dexamethasone, versus a sham procedure. Despite a more rapid initial improvement with dexamethasone, the number of patients whose reading ability improved at 6 months did not significantly differ between the groups. A retrospective subgroup analysis raised the possibility that dexamethasone implants may be beneficial in patients with central retinal vein occlusion. The adverse effects of dexamethasone intravitreal implants are the same as those of intraocular steroid injections, including elevated intraocular pressure (25% of patients), cataracts (27%), conjunctival haemorrhage (20%), and ocular pain. In practice, dexamethasone intravitreal implants do not have a positive harm-benefit balance in most patients with macular oedema following retinal vein occlusion. More rapid recovery after central vein occlusion remains to be confirmed. Pending such studies, it is better to avoid using dexamethasone implants. Patients should instead receive ophthalmologic monitoring to detect and manage possible complications, and any risk factors should be treated.

  17. Analog synthetic biology.

    PubMed

    Sarpeshkar, R

    2014-03-28

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog-digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA-protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  18. Analog synthetic biology

    PubMed Central

    Sarpeshkar, R.

    2014-01-01

    We analyse the pros and cons of analog versus digital computation in living cells. Our analysis is based on fundamental laws of noise in gene and protein expression, which set limits on the energy, time, space, molecular count and part-count resources needed to compute at a given level of precision. We conclude that analog computation is significantly more efficient in its use of resources than deterministic digital computation even at relatively high levels of precision in the cell. Based on this analysis, we conclude that synthetic biology must use analog, collective analog, probabilistic and hybrid analog–digital computational approaches; otherwise, even relatively simple synthetic computations in cells such as addition will exceed energy and molecular-count budgets. We present schematics for efficiently representing analog DNA–protein computation in cells. Analog electronic flow in subthreshold transistors and analog molecular flux in chemical reactions obey Boltzmann exponential laws of thermodynamics and are described by astoundingly similar logarithmic electrochemical potentials. Therefore, cytomorphic circuits can help to map circuit designs between electronic and biochemical domains. We review recent work that uses positive-feedback linearization circuits to architect wide-dynamic-range logarithmic analog computation in Escherichia coli using three transcription factors, nearly two orders of magnitude more efficient in parts than prior digital implementations. PMID:24567476

  19. Implant interactions with orthodontics.

    PubMed

    Celenza, Frank

    2012-09-01

    Many situations arise in which orthodontic therapy in conjunction with implant modalities is beneficial, relevant or necessary. These situations might entail orthodontic treatment preparatory to the placement of an implant, such as in the site preparation for implant placement. Traditionally, this has been somewhat well understood, but there are certain guidelines that must be adhered to as well as diagnostic steps that must be followed. Provision of adequate space for implant placement is of paramount importance, but there is also the consideration of tissue manipulation and remodeling which orthodontic therapy can achieve very predictably and orthodontists should be well versed in harnessing and employing this modality of site preparation. In this way, hopeless teeth that are slated for extraction can still be utilized by orthodontic extraction to augment tissues, both hard and soft, thereby facilitating site development. On the corollary, and representing a significant shift in treatment sequencing, there are many situations in which orthodontic mechanotherapy can be simplified, expedited, and facilitated by the placement of an implant and utilization as an integral part of the mechanotherapy. Implants have proven to provide excellent anchorage, and have resulted in a new class of anchorage known as "absolute anchorage". Implants can be harnessed as anchors both in a direct and indirect sense, depending upon the dictates of the case. Further, this has led to the development of orthodontic miniscrew systems and techniques, which can have added features such as flexibility in location and placement, as well as ease of use and removal. As orthodontic appliances evolve, the advent of aligner therapy has become mainstream and well accepted, and many of the aforementioned combined treatment modalities can and should be incorporated into this relatively new treatment modality as well. PMID:23040348

  20. Scuba diving with cochlear implants.

    PubMed

    Kompis, Martin; Vibert, Dominique; Senn, Pascal; Vischer, Mattheus W; Häusler, Rudolf

    2003-05-01

    We report on a patient with bilateral cochlear implants (a Med-El Combi40 and a Med-El Combi40+), as well as considerable experience in scuba diving with both of his implants. After having been exposed to 68 and 89 dives, respectively, in depths of up to 43 m, both cochlear implants are in working order and the patient continues to receive excellent speech recognition scores with both cochlear implant systems. The presented data show that scuba diving after cochlear implantation is possible over a considerable number of dives without any major negative impact on the implants.

  1. [Subretinal visual implants].

    PubMed

    Stingl, K; Greppmaier, U; Wilhelm, B; Zrenner, E

    2010-12-01

    Visual implants are medical technologies that replace parts of the visual neuronal pathway. The subretinal implant developed by our group is being used in a human trials since 2005 and replaces the function of degenerated photoreceptors by an electronic device in blind patients. The subretinal implant consists of a 70-µm thin microchip with 1500 microphotodiodes each with an amplifier and an electrode with area of 3 mm × 3 mm. The power supply is provided by a subdermal power supply cable. The microchip is implanted under the macula and transforms the light signal into an electrical one, which is referred directly to the bipolar cells. Requirements for a good function of the implant are a preserved function of the inner retina, as well as clear optic media and a good visual acuity in the earlier life. The current technology can mediate a visual field of 10 - 12° and a computed resolution of up to 0.25° visual angle (corresponding to a visual acuity of 63 / 1000 - 80 / 1000) in blind patients. The so far best results from our studies reached a visual acuity of 21 / 1000 in blind retinitis pigmentosa patients. This overview is intended to inform the ophthalmologist about the current state of the technology and help him/her to advise interested patients.

  2. Progress toward synthetic cells.

    PubMed

    Blain, J Craig; Szostak, Jack W

    2014-01-01

    The complexity of even the simplest known life forms makes efforts to synthesize living cells from inanimate components seem like a daunting task. However, recent progress toward the creation of synthetic cells, ranging from simple protocells to artificial cells approaching the complexity of bacteria, suggests that the synthesis of life is now a realistic goal. Protocell research, fueled by advances in the biophysics of primitive membranes and the chemistry of nucleic acid replication, is providing new insights into the origin of cellular life. Parallel efforts to construct more complex artificial cells, incorporating translational machinery and protein enzymes, are providing information about the requirements for protein-based life. We discuss recent advances and remaining challenges in the synthesis of artificial cells, the possibility of creating new forms of life distinct from existing biology, and the promise of this research for gaining a deeper understanding of the nature of living systems. PMID:24606140

  3. Synthetic antibiofilm peptides.

    PubMed

    de la Fuente-Núñez, César; Cardoso, Marlon Henrique; de Souza Cândido, Elizabete; Franco, Octavio Luiz; Hancock, Robert E W

    2016-05-01

    Bacteria predominantly exist as multicellular aggregates known as biofilms that are associated with at least two thirds of all infections and exhibit increased adaptive resistance to conventional antibiotic therapies. Therefore, biofilms are major contributors to the global health problem of antibiotic resistance, and novel approaches to counter them are urgently needed. Small molecules of the innate immune system called host defense peptides (HDPs) have emerged as promising templates for the design of potent, broad-spectrum antibiofilm agents. Here, we review recent developments in the new field of synthetic antibiofilm peptides, including mechanistic insights, synergistic interactions with available antibiotics, and their potential as novel antimicrobials against persistent infections caused by biofilms. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26724202

  4. Entraining synthetic genetic oscillators

    NASA Astrophysics Data System (ADS)

    Wagemakers, Alexandre; Buldú, Javier M.; Sanjuán, Miguel A. F.; de Luis, Oscar; Izquierdo, Adriana; Coloma, Antonio

    2009-09-01

    We propose a new approach for synchronizing a population of synthetic genetic oscillators, which consists in the entrainment of a colony of repressilators by external modulation. We present a model where the repressilator dynamics is affected by periodic changes in temperature. We introduce an additional plasmid in the bacteria in order to correlate the temperature variations with the enhancement of the transcription rate of a certain gene. This can be done by introducing a promoter that is related to the heat shock response. This way, the expression of that gene results in a protein that enhances the overall oscillations. Numerical results show coherent oscillations of the population for a certain range of the external frequency, which is in turn related to the natural oscillation frequency of the modified repressilator. Finally we study the transient times related with the loss of synchronization and we discuss possible applications in biotechnology of large-scale production coupled to synchronization events induced by heat shock.

  5. Immunological aspects of implantation and implantation failure.

    PubMed

    Johnson, P M; Christmas, S E; Vince, G S

    1999-12-01

    The human endometrium contains a significant proportion of leukocytes (8-35% of all cells), the absolute numbers and proportions varying during both the menstrual cycle and early in pregnancy. T cells, macrophages and a population of phenotypically unusual large granular lymphocytes (LGL) are commonly present, although B cells are absent. Relative T cell numbers decrease significantly in first trimester decidua, and hence are unlikely to play an important role in maintenance of human pregnancy, but T cells could be important in implantation where their relative numbers are greater. In addition to producing cytokines, local tissue macrophages may provide an immediate antigen non-specific host defence to infection. Most attention has, nevertheless, focused on a role for LGL in implantation and maintenance of pregnancy since, at the time of implantation, LGL comprise 70-80% of the total endometrial leukocyte population. Although endometrial LGL have been shown to express natural killer (NK) cell-type cytotoxicity against classical NK cell targets, such cytotoxicity against trophoblast is induced only after activation by interleukin (IL)-2. Selective expression of the unusual class I human leukocyte antigen (HLA) molecule, HLA-G, by extravillous cytotrophoblast may assist in protecting invasive cytotrophoblast from potential maternal NK cell attack, probably via interactions with killer inhibitory receptor molecules on LGL. Many cytokines have been demonstrated to be expressed at the maternal-fetal interface although, currently, in mice only two (IL-11 and leukaemia inhibitory factor) appear to be absolutely essential for successful pregnancy outcome. Immune effector cells and cytokines may also play a role in human pregnancy pathologies, such as recurrent early pregnancy loss.

  6. Dental Implant Complications.

    PubMed

    Liaw, Kevin; Delfini, Ronald H; Abrahams, James J

    2015-10-01

    Dental implants have increased in the last few decades thus increasing the number of complications. Since many of these complications are easily diagnosed on postsurgical images, it is important for radiologists to be familiar with them and to be able to recognize and diagnose them. Radiologists should also have a basic understanding of their treatment. In a pictorial fashion, this article will present the basic complications of dental implants which we have divided into three general categories: biomechanical overload, infection or inflammation, and other causes. Examples of implant fracture, loosening, infection, inflammation from subgingival cement, failure of bone and soft tissue preservation, injury to surround structures, and other complications will be discussed as well as their common imaging appearances and treatment. Lastly, we will review pertinent dental anatomy and important structures that are vital for radiologists to evaluate in postoperative oral cavity imaging.

  7. Synthetic Genomics and Synthetic Biology Applications Between Hopes and Concerns

    PubMed Central

    König, Harald; Frank, Daniel; Heil, Reinhard; Coenen, Christopher

    2013-01-01

    New organisms and biological systems designed to satisfy human needs are among the aims of synthetic genomics and synthetic biology. Synthetic biology seeks to model and construct biological components, functions and organisms that do not exist in nature or to redesign existing biological systems to perform new functions. Synthetic genomics, on the other hand, encompasses technologies for the generation of chemically-synthesized whole genomes or larger parts of genomes, allowing to simultaneously engineer a myriad of changes to the genetic material of organisms. Engineering complex functions or new organisms in synthetic biology are thus progressively becoming dependent on and converging with synthetic genomics. While applications from both areas have been predicted to offer great benefits by making possible new drugs, renewable chemicals or clean energy, they have also given rise to concerns about new safety, environmental and socio-economic risks – stirring an increasingly polarizing debate. Here we intend to provide an overview on recent progress in biomedical and biotechnological applications of synthetic genomics and synthetic biology as well as on arguments and evidence related to their possible benefits, risks and governance implications. PMID:23997647

  8. Implantable Heart Aid

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Medrad utilized NASA's Apollo technology to develop a new device called the AID implantable automatic pulse generator which monitors the heart continuously, recognizes the onset of ventricular fibrillation and delivers a corrective electrical shock. AID pulse generator is, in effect, a miniaturized version of the defibrillator used by emergency squads and hospitals to restore rhythmic heartbeat after fibrillation, but has the unique advantage of being permanently available to the patient at risk. Once implanted, it needs no specially trained personnel or additional equipment. AID system consists of a microcomputer, a power source and two electrodes which sense heart activity.

  9. Hydroxylapatite Otologic Implants

    SciTech Connect

    McMillan, A.D.; Lauf, R.J.; Beale, B.; Johnson, R.

    2000-01-01

    A Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Research Corporation (LMER) and Smith and Nephew Richards Inc. of Bartlett, TN, was initiated in March 1997. The original completion date for the Agreement was March 25, 1998. The purpose of this work is to develop and commercialize net shape forming methods for directly creating dense hydroxylapatite (HA) ceramic otologic implants. The project includes three tasks: (1) modification of existing gelcasting formulations to accommodate HA slurries; (2) demonstration of gelcasting to fabricate green HA ceramic components of a size and shape appropriate to otologic implants: and (3) sintering and evaluation of the HA components.

  10. Multichannel extracochlear implant.

    PubMed

    Pulec, J L; Smith, J C; Lewis, M L; Hortmann, G

    1989-03-01

    The transcutaneous eight-channel extracochlear implant has undergone continuous revision to simplify the surgical technique, to minimize patient morbidity, and to improve performance. The extracochlear electrode array has been miniaturized so that it can be inserted through the facial recess without disturbing the external auditory canal, tympanic membrane, or malleus. The use of the remote antenna placed around the external auditory canal has greatly increased battery life and patient comfort. With its simplified incisions, the surgical procedure can be performed as out-patient surgery. Preoperative cochlear nerve testing and use of evoked response cochlear nerve testing allow preadjustment of the speech processor. Current features and performance of the implant are discussed.

  11. Current trends in dental implants

    PubMed Central

    Gaviria, Laura; Salcido, John Paul; Guda, Teja

    2014-01-01

    Tooth loss is very a very common problem; therefore, the use of dental implants is also a common practice. Although research on dental implant designs, materials and techniques has increased in the past few years and is expected to expand in the future, there is still a lot of work involved in the use of better biomaterials, implant design, surface modification and functionalization of surfaces to improve the long-term outcomes of the treatment. This paper provides a brief history and evolution of dental implants. It also describes the types of implants that have been developed, and the parameters that are presently used in the design of dental implants. Finally, it describes the trends that are employed to improve dental implant surfaces, and current technologies used for the analysis and design of the implants. PMID:24868501

  12. Current trends in dental implants.

    PubMed

    Gaviria, Laura; Salcido, John Paul; Guda, Teja; Ong, Joo L

    2014-04-01

    Tooth loss is very a very common problem; therefore, the use of dental implants is also a common practice. Although research on dental implant designs, materials and techniques has increased in the past few years and is expected to expand in the future, there is still a lot of work involved in the use of better biomaterials, implant design, surface modification and functionalization of surfaces to improve the long-term outcomes of the treatment. This paper provides a brief history and evolution of dental implants. It also describes the types of implants that have been developed, and the parameters that are presently used in the design of dental implants. Finally, it describes the trends that are employed to improve dental implant surfaces, and current technologies used for the analysis and design of the implants.

  13. Ion implantation in silicate glasses

    SciTech Connect

    Arnold, G.W.

    1993-12-01

    This review examines the effects of ion implantation on the physical properties of silicate glasses, the compositional modifications that can be brought about, and the use of metal implants to form colloidal nanosize particles for increasing the nonlinear refractive index.

  14. The ruptured PIP breast implant.

    PubMed

    Helyar, V; Burke, C; McWilliams, S

    2013-08-01

    Public concern erupted about the safety of Poly Implant Prothèse (PIP) breast implants when it was revealed in 2011 that they contained an inferior, unlicensed industrial-grade silicone associated with a high rate of rupture. There followed national guidance for UK clinicians, which led to a considerable increase in referrals of asymptomatic women for breast implant assessment. In this review we discuss possible approaches to screening the PIP cohort and the salient characteristics of a ruptured implant. PMID:23622796

  15. Synthetic Foveal Imaging Technology

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael; Monacos, Steve; Nikzad, Shouleh

    2009-01-01

    Synthetic Foveal imaging Technology (SyFT) is an emerging discipline of image capture and image-data processing that offers the prospect of greatly increased capabilities for real-time processing of large, high-resolution images (including mosaic images) for such purposes as automated recognition and tracking of moving objects of interest. SyFT offers a solution to the image-data processing problem arising from the proposed development of gigapixel mosaic focal-plane image-detector assemblies for very wide field-of-view imaging with high resolution for detecting and tracking sparse objects or events within narrow subfields of view. In order to identify and track the objects or events without the means of dynamic adaptation to be afforded by SyFT, it would be necessary to post-process data from an image-data space consisting of terabytes of data. Such post-processing would be time-consuming and, as a consequence, could result in missing significant events that could not be observed at all due to the time evolution of such events or could not be observed at required levels of fidelity without such real-time adaptations as adjusting focal-plane operating conditions or aiming of the focal plane in different directions to track such events. The basic concept of foveal imaging is straightforward: In imitation of a natural eye, a foveal-vision image sensor is designed to offer higher resolution in a small region of interest (ROI) within its field of view. Foveal vision reduces the amount of unwanted information that must be transferred from the image sensor to external image-data-processing circuitry. The aforementioned basic concept is not new in itself: indeed, image sensors based on these concepts have been described in several previous NASA Tech Briefs articles. Active-pixel integrated-circuit image sensors that can be programmed in real time to effect foveal artificial vision on demand are one such example. What is new in SyFT is a synergistic combination of recent

  16. Recent advances in synthetic biosafety.

    PubMed

    Simon, Anna J; Ellington, Andrew D

    2016-01-01

    Synthetically engineered organisms hold promise for a broad range of medical, environmental, and industrial applications. Organisms can potentially be designed, for example, for the inexpensive and environmentally benign synthesis of pharmaceuticals and industrial chemicals, for the cleanup of environmental pollutants, and potentially even for biomedical applications such as the targeting of specific diseases or tissues. However, the use of synthetically engineered organisms comes with several reasonable safety concerns, one of which is that the organisms or their genes could escape their intended habitats and cause environmental disruption. Here we review key recent developments in this emerging field of synthetic biocontainment and discuss further developments that might be necessary for the widespread use of synthetic organisms. Specifically, we discuss the history and modern development of three strategies for the containment of synthetic microbes: addiction to an exogenously supplied ligand; self-killing outside of a designated environment; and self-destroying encoded DNA circuitry outside of a designated environment. PMID:27635235

  17. Synthetic cannabis and respiratory depression.

    PubMed

    Jinwala, Felecia N; Gupta, Mayank

    2012-12-01

    In recent years, synthetic cannabis use has been increasing in appeal among adolescents, and its use is now at a 30 year peak among high school seniors. The constituents of synthetic cannabis are difficult to monitor, given the drug's easy accessibility. Currently, 40 U.S. states have banned the distribution and use of some known synthetic cannabinoids, and have included these drugs in the Schedule I category. The depressive respiratory effect in humans caused by synthetic cannabis inhalation has not been thoroughly investigated in the medical literature. We are the first to report, to our knowledge, two cases of self-reported synthetic cannabis use leading to respiratory depression and necessary intubation. PMID:23234589

  18. Recent advances in synthetic biosafety

    PubMed Central

    Simon, Anna J.; Ellington, Andrew D.

    2016-01-01

    Synthetically engineered organisms hold promise for a broad range of medical, environmental, and industrial applications. Organisms can potentially be designed, for example, for the inexpensive and environmentally benign synthesis of pharmaceuticals and industrial chemicals, for the cleanup of environmental pollutants, and potentially even for biomedical applications such as the targeting of specific diseases or tissues. However, the use of synthetically engineered organisms comes with several reasonable safety concerns, one of which is that the organisms or their genes could escape their intended habitats and cause environmental disruption. Here we review key recent developments in this emerging field of synthetic biocontainment and discuss further developments that might be necessary for the widespread use of synthetic organisms. Specifically, we discuss the history and modern development of three strategies for the containment of synthetic microbes: addiction to an exogenously supplied ligand; self-killing outside of a designated environment; and self-destroying encoded DNA circuitry outside of a designated environment.

  19. Recent advances in synthetic biosafety

    PubMed Central

    Simon, Anna J.; Ellington, Andrew D.

    2016-01-01

    Synthetically engineered organisms hold promise for a broad range of medical, environmental, and industrial applications. Organisms can potentially be designed, for example, for the inexpensive and environmentally benign synthesis of pharmaceuticals and industrial chemicals, for the cleanup of environmental pollutants, and potentially even for biomedical applications such as the targeting of specific diseases or tissues. However, the use of synthetically engineered organisms comes with several reasonable safety concerns, one of which is that the organisms or their genes could escape their intended habitats and cause environmental disruption. Here we review key recent developments in this emerging field of synthetic biocontainment and discuss further developments that might be necessary for the widespread use of synthetic organisms. Specifically, we discuss the history and modern development of three strategies for the containment of synthetic microbes: addiction to an exogenously supplied ligand; self-killing outside of a designated environment; and self-destroying encoded DNA circuitry outside of a designated environment. PMID:27635235

  20. Semiconductor Ion Implanters

    NASA Astrophysics Data System (ADS)

    MacKinnon, Barry A.; Ruffell, John P.

    2011-06-01

    In 1953 the Raytheon CK722 transistor was priced at 7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at 6.2 billion! Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing `only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around 2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  1. Elementary Implantable Force Sensor

    PubMed Central

    Wachs, Rebecca A.; Ellstein, David; Drazan, John; Healey, Colleen P.; Uhl, Richard L.; Connor, Kenneth A.

    2014-01-01

    Implementing implantable sensors which are robust enough to maintain long term functionality inside the body remains a significant challenge. The ideal implantable sensing system is one which is simple and robust; free from batteries, telemetry, and complex electronics. We have developed an elementary implantable sensor for orthopaedic smart implants. The sensor requires no telemetry and no batteries to communicate wirelessly. It has no on-board signal conditioning electronics. The sensor itself has no electrical connections and thus does not require a hermetic package. The sensor is an elementary L-C resonator which can function as a simple force transducer by using a solid dielectric material of known stiffness between two parallel Archimedean coils. The operating characteristics of the sensors are predicted using a simplified, lumped circuit model. We have demonstrated sensor functionality both in air and in saline. Our preliminary data indicate that the sensor can be reasonably well modeled as a lumped circuit to predict its response to loading. PMID:24883335

  2. Semiconductor Ion Implanters

    SciTech Connect

    MacKinnon, Barry A.; Ruffell, John P.

    2011-06-01

    In 1953 the Raytheon CK722 transistor was priced at $7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at $6.2 billion. Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing 'only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around $2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  3. Remote actuated valve implant

    DOEpatents

    McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.; Ericson, Milton Nance; Baba, Justin S.; Wilgen, John B.; Evans, Boyd Mccutchen

    2016-05-10

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  4. Ion implantation in polymers

    NASA Astrophysics Data System (ADS)

    Wintersgill, M. C.

    1984-02-01

    An introductory overview will be given of the effects of ion implantation on polymers, and certain areas will be examined in more detail. Radiation effects in general and ion implantation in particular, in the field of polymers, present a number of contrasts with those in ionic crystals, the most obvious difference being that the chemical effects of both the implanted species and the energy transfer to the host may profoundly change the nature of the target material. Common effects include crosslinking and scission of polymer chains, gas evolution, double bond formation and the formation of additional free radicals. Research has spanned the chemical processes involved, including polymerization reactions achievable only with the use of radiation, to applied research dealing both with the effects of radiation on polymers already in commercial use and the tailoring of new materials to specific applications. Polymers are commonly divided into two groups, in describing their behavior under irradiation. Group I includes materials which form crosslinks between molecules, whereas Group II materials tend to degrade. In basic research, interest has centered on Group I materials and of these polyethylene has been studied most intensively. Applied materials research has investigated a variety of polymers, particularly those used in cable insulation, and those utilized in ion beam lithography of etch masks. Currently there is also great interest in enhancing the conducting properties of polymers, and these uses would tend to involve the doping capabilities of ion implantation, rather than the energy deposition.

  5. Peritoneal trophoblastic implant.

    PubMed

    Rachagan, S P; Kutty, K; Govindan, K S

    1997-09-01

    A case of persistent trophoblastic tissue on the pelvic peritoneum is presented. While most cases are secondary to conservative surgery for tubal ectopic pregnancy, primary implantation can also occur as highlighted by this case. A brief pathophysiology of the condition is presented. The importance of monitoring the serum for beta subunit human chorionic gonadotrophin (HCG) is emphasised.

  6. Implantable Drug Dispenser

    NASA Technical Reports Server (NTRS)

    Collins, E. R. J.

    1983-01-01

    Drugs such as insulin are injected as needed directly into bloodstream by compact implantable dispensing unit. Two vapor cavities produce opposing forces on drug-chamber diaphragm. Heaters in cavities allow control of direction and rate of motion of bellows. Dispensing capsule fitted with coil so batteries can be recharged by induction.

  7. Remote actuated valve implant

    DOEpatents

    McKnight, Timothy E; Johnson, Anthony; Moise, Jr., Kenneth J; Ericson, Milton Nance; Baba, Justin S; Wilgen, John B; Evans, III, Boyd McCutchen

    2014-02-25

    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  8. Implantable electrical device

    NASA Technical Reports Server (NTRS)

    Jhabvala, M. D. (Inventor)

    1982-01-01

    A fully implantable and self contained device is disclosed composed of a flexible electrode array for surrounding damaged nerves and a signal generator for driving the electrode array with periodic electrical impulses of nanoampere magnitude to induce regeneration of the damaged nerves.

  9. Implantable Impedance Plethysmography

    PubMed Central

    Theodor, Michael; Ruh, Dominic; Ocker, Martin; Spether, Dominik; Förster, Katharina; Heilmann, Claudia; Beyersdorf, Friedhelm; Manoli, Yiannos; Zappe, Hans; Seifert, Andreas

    2014-01-01

    We demonstrate by theory, as well as by ex vivo and in vivo measurements that impedance plethysmography, applied extravascularly directly on large arteries, is a viable method for monitoring various cardiovascular parameters, such as blood pressure, with high accuracy. The sensor is designed as an implant to monitor cardiac events and arteriosclerotic progression over the long term. PMID:25123467

  10. Effect of Allogeneic Platelet Lysate and Cyanoacrylate Tissue Glue on the Fibrovascularization of the Porous Polyethylene Implant.

    PubMed

    Ozturk, Sinan; Sahin, Cihan; Tas, Arzu Caputcu; Muftuoglu, Tuba; Karagoz, Huseyin

    2016-01-01

    Because of limited autogenous tissue sources, donor site morbidity, and difficulty of shaping the autologous tissue, surgeons often need to use alloplastic frameworks in reconstruction of 3-dimensional tissue defects. Synthetic porous polyethylene (PP) implant is widely used in plastic surgery for 3-dimensional reconstruction of the lost or highly deformed tissues. One of the main factors of PP implant exposure is delayed fibrovascular ingrowth. In the present study, the authors investigated the effect allogeneic plateletlysate (PL) and cyanoacrylate tissue glue (CTG) (2-octyl cyanoacrylate) on the fibrovascularization of the PP implant.Twenty adult female Wistar rats were divided into 4 groups equally, according to the different surgical techniques and implanted materials used. Only PP implant was implanted subcutaneously through a skin incision on the chest wall skin of the rats in the control group; however, CTG was applied with PP implant in the cyanoacrylate group, PL was applied with PP implant in the platelet group, CTG and platelet was applied together with PP implant in the combination group. All of the implants in each group were histologically assessed at postoperative second week. Determination of the collagen density in the tissues, inflammation, and necrosis and vascularization status was assessed semiquantitatively.A denser collagen structure, low inflammation, and necrosis were found in PL groups. There was, however, a significant decrease in vascular density with PL-treated groups. PL treatment may have a potential to reduce complications related to PP implants. PMID:26703066

  11. Ecotoxicology of synthetic pyrethroids.

    PubMed

    Maund, S J; Campbell, P J; Giddings, J M; Hamer, M J; Henry, K; Pilling, E D; Warinton, J S; Wheeler, J R

    2012-01-01

    In this chapter we review the ecotoxicology of the synthetic pyrethroids (SPs). SPs are potent, broad-spectrum insecticides. Their effects on a wide range of nontarget species have been broadly studied, and there is an extensive database available to evaluate their effects. SPs are highly toxic to fish and aquatic invertebrates in the laboratory, but effects in the field are mitigated by rapid dissipation and degradation. Due to their highly lipophilic nature, SPs partition extensively into sediments. Recent studies have shown that toxicity in sediment can be predicted on the basis of equilibrium partitioning, and whilst other factors can influence this, organic carbon content is a key determining variable. At present for SPs, there is no clear evidence for adverse population-relevant effects with an underlying endocrine mode of action. SPs have been studied intensively in aquatic field studies, and their effects under field conditions are mitigated from those measured in the laboratory by their rapid dissipation and degradation. Studies with a range of test systems have shown consistent aquatic field endpoints across a variety of geographies and trophic states. SPs are also highly toxic to bees and other nontarget arthropods in the laboratory. These effects are mitigated in the field through repellency and dissipation of residues, and recovery from any adverse effects tends to be rapid.

  12. Synthetic retinoids in dermatology

    PubMed Central

    Heller, Elizabeth H.; Shiffman, Norman J.

    1985-01-01

    The potential of vitamin A, or retinol, in the treatment of a variety of skin diseases has long been recognized, but because of serious toxic effects this substance generally could not be used. The recent development and marketing of two relatively nontoxic synthetic analogues, which are known as retinoids, has made it possible to treat some of the diseases that are resistant to standard forms of therapy. Isotretinoin is very effective in cystic and conglobate acne, while etretinate is especially useful in the more severe forms of psoriasis. Good results have also been obtained in other disorders of keratinization. Vitamin A and its derivatives apparently have an antineoplastic effect as well and may come to be used in both the prevention and the treatment of epithelial cancer. In many of these diseases the retinoids act by enhancing the normal differentiation and proliferation of epidermal tissues, but the exact mechanisms are not well understood. Their influence on the intracellular polyamines that control the synthesis of nucleic acids and proteins may be an important factor. Although the retinoids have few serious systemic effects, they are teratogenic, and because they persist in the body their use in women of childbearing potential is limited. ImagesFig. 3 PMID:3158386

  13. Synthetic molecular walkers.

    PubMed

    Leigh, David A; Lewandowska, Urszula; Lewandowski, Bartosz; Wilson, Miriam R

    2014-01-01

    In biological systems, molecular motors have been developed to harness Brownian motion and perform specific tasks. Among the cytoskeletal motor proteins, kinesins ensure directional transport of cargoes to the periphery of the cell by taking discrete steps along microtubular tracks. In the past decade there has been an increasing interest in the development of molecules that mimic aspects of the dynamics of biological systems and can became a starting point for the creation of artificial transport systems.To date, both DNA-based and small-molecule walkers have been developed, each taking advantage of the different chemistries available to them. DNA strollers exploit orthogonal base pairing and utilize strand-displacement reactions to control the relative association of the component parts. Small-molecule walkers take advantage of the reversibility of weak noncovalent interactions as well as the robustness of dynamic covalent bonds in order to transport molecular fragments along surfaces and molecular tracks using both diffusional processes and ratchet mechanisms. Here we review both types of synthetic systems, including their designs, dynamics, and how they are being used to perform functions by controlled mechanical motion at the molecular level.

  14. Computing with synthetic protocells.

    PubMed

    Courbet, Alexis; Molina, Franck; Amar, Patrick

    2015-09-01

    In this article we present a new kind of computing device that uses biochemical reactions networks as building blocks to implement logic gates. The architecture of a computing machine relies on these generic and composable building blocks, computation units, that can be used in multiple instances to perform complex boolean functions. Standard logical operations are implemented by biochemical networks, encapsulated and insulated within synthetic vesicles called protocells. These protocells are capable of exchanging energy and information with each other through transmembrane electron transfer. In the paradigm of computation we propose, protoputing, a machine can solve only one problem and therefore has to be built specifically. Thus, the programming phase in the standard computing paradigm is represented in our approach by the set of assembly instructions (specific attachments) that directs the wiring of the protocells that constitute the machine itself. To demonstrate the computing power of protocellular machines, we apply it to solve a NP-complete problem, known to be very demanding in computing power, the 3-SAT problem. We show how to program the assembly of a machine that can verify the satisfiability of a given boolean formula. Then we show how to use the massive parallelism of these machines to verify in less than 20 min all the valuations of the input variables and output a fluorescent signal when the formula is satisfiable or no signal at all otherwise.

  15. The reverse zygomatic implant: a new implant for maxillofacial reconstruction.

    PubMed

    Dawood, Andrew; Collier, Jonathan; Darwood, Alastair; Tanner, Susan

    2015-01-01

    This case report describes the rehabilitation of a patient who had been treated with a hemimaxillectomy, reconstruction with a latissimus dorsi vascularized free flap, and radiotherapy for carcinoma of the sinus some years previously. Limited jaw opening, difficult access through the flap to the bony site, and the very small amount of bone available in which to anchor the implant inspired the development and use of a new "reverse zygomatic" implant. For this treatment, site preparation and implant insertion were accomplished using an extraoral approach. The implant was used along with two other conventional zygomatic implants to provide support for a milled titanium bar and overdenture to rehabilitate the maxilla. Two years later, the patient continues to enjoy a healthy reconstruction. The reverse zygomatic implant appears to show promise as a useful addition to the implant armamentarium for the treatment of the patient undergoing maxillectomy. PMID:26574864

  16. Synthetic biology: lessons from the history of synthetic organic chemistry.

    PubMed

    Yeh, Brian J; Lim, Wendell A

    2007-09-01

    The mid-nineteenth century saw the development of a radical new direction in chemistry: instead of simply analyzing existing molecules, chemists began to synthesize them--including molecules that did not exist in nature. The combination of this new synthetic approach with more traditional analytical approaches revolutionized chemistry, leading to a deep understanding of the fundamental principles of chemical structure and reactivity and to the emergence of the modern pharmaceutical and chemical industries. The history of synthetic chemistry offers a possible roadmap for the development and impact of synthetic biology, a nascent field in which the goal is to build novel biological systems. PMID:17710092

  17. Synthetic biology: Understanding biological design from synthetic circuits

    PubMed Central

    Mukherji, Shankar; van Oudenaarden, Alexander

    2011-01-01

    An important aim of synthetic biology is to uncover the design principles of natural biological systems through the rational design of gene and protein circuits. Here we highlight how the process of engineering biological systems — from synthetic promoters to the control of cell–cell interactions — has contributed to our understanding of how endogenous systems are put together and function. Synthetic biological devices allow us to intuitively grasp the ranges of behavior generated by simple biological circuits, such as linear cascades and interlocking feedback loops, as well as to exert control over natural processes such as gene expression and population dynamics. PMID:19898500

  18. Bistatic synthetic aperture radar

    NASA Astrophysics Data System (ADS)

    Yates, Gillian

    Synthetic aperture radar (SAR) allows all-weather, day and night, surface surveillance and has the ability to detect, classify and geolocate objects at long stand-off ranges. Bistatic SAR, where the transmitter and the receiver are on separate platforms, is seen as a potential means of countering the vulnerability of conventional monostatic SAR to electronic countermeasures, particularly directional jamming, and avoiding physical attack of the imaging platform. As the receiving platform can be totally passive, it does not advertise its position by RF emissions. The transmitter is not susceptible to jamming and can, for example, operate at long stand-off ranges to reduce its vulnerability to physical attack. This thesis examines some of the complications involved in producing high-resolution bistatic SAR imagery. The effect of bistatic operation on resolution is examined from a theoretical viewpoint and analytical expressions for resolution are developed. These expressions are verified by simulation work using a simple 'point by point' processor. This work is extended to look at using modern practical processing engines for bistatic geometries. Adaptations of the polar format algorithm and range migration algorithm are considered. The principal achievement of this work is a fully airborne demonstration of bistatic SAR. The route taken in reaching this is given, along with some results. The bistatic SAR imagery is analysed and compared to the monostatic imagery collected at the same time. Demonstrating high-resolution bistatic SAR imagery using two airborne platforms represents what I believe to be a European first and is likely to be the first time that this has been achieved outside the US (the UK has very little insight into US work on this topic). Bistatic target characteristics are examined through the use of simulations. This also compares bistatic imagery with monostatic and gives further insight into the utility of bistatic SAR.

  19. Synthetic inhibitors of elastase.

    PubMed

    Edwards, P D; Bernstein, P R

    1994-03-01

    For more than two decades investigators around the world, in both academic and industrial institutions, have been developing inhibitors of human neutrophil elastase. A number of very elegant and insightful strategies have been reported. In the case of reversible peptidic inhibitors, this has resulted in the identification of some extremely potent compounds with dissociation constants in the 10(-11) M range. This is quite an accomplishment considering that these low molecular-weight inhibitors are only tri- and tetrapeptides. In the case of the heterocyclic-based inhibitors, the challenge of balancing the heterocycle's inherent reactivity and aqueous stability with the stability of the enzyme-inhibitor adduct has been meet by either using a latent, reactive functionality which is only activated within the enzyme, or by incorporating features which selectively obstruct deacylation but have little effect on the enzyme acylation step. The underlying goal of this research has been the identification of agents to treat diseases associated with HNE. Several animal models have been developed for evaluating the in vivo activity of elastase inhibitors, and compounds have been shown to be effective in all of these models by the intravenous, intratrachael or oral routes of administration. However, only a very small percentage of compounds have possessed all the necessary properties, including lack of toxicity, for progression into the clinic. The peptidyl TFMK ICI 200,880 (25-12) has many of the desired characteristics of a drug to treat the diseases associated with HNE: chemical stability, in vitro and in vivo activity, a long duration of action, and adequate metabolic stability. Currently ICI 200,880 is the only low molecular-weight HNE inhibitor known to be undergoing clinical trials, and may be the compound which finally demonstrates the clinical utility of a synthetic HNE inhibitor. PMID:8189835

  20. Spicing thing up: Synthetic cannabinoids

    PubMed Central

    Spaderna, Max; Addy, Peter H; D’Souza, Deepak Cyril

    2013-01-01

    Rationale Recently, products containing synthetic cannabinoids, collectively referred to as Spice, are increasingly being used recreationally. Objectives The availability, acute subjective effects—including self-reports posted on Erowid—laboratory detection, addictive potential, and regulatory challenges of the Spice phenomenon are reviewed. Results Spice is sold under the guise of potpourri or incense. Unlike THC, the synthetic cannabinoids present in Spice are high-potency, high-efficacy, cannabinoid-receptor full agonists. Since standard urine toxicology does not test for the synthetic cannabinoids in Spice, it is often used by those who want to avoid detection of drug use. These compounds have not yet been subjected to rigorous testing in humans. Acute psychoactive effects include changes in mood, anxiety, perception, thinking, memory, and attention. Adverse effects include anxiety, agitation, panic, dysphoria, psychosis, and bizarre behavior. Psychosis outcomes associated with Spice provide additional data linking cannabinoids and psychosis. Adverse events necessitating intervention by Poison Control Centers, law enforcement, emergency responders, and hospitals are increasing. Despite statutes prohibiting the manufacture, distribution, and sale of Spice products, manufacturers are replacing banned compounds with newer synthetic cannabinoids that are not banned. Conclusions There is an urgent need for better research on the effects of synthetic cannabinoids to help clinicians manage adverse events and to better understand cannabinoid pharmacology in humans. The reported psychosis outcomes associated with synthetic cannabinoids contribute to the ongoing debate on the association between cannabinoids and psychosis. Finally, drug-detection tests for synthetic cannabinoids need to become clinically available. PMID:23836028

  1. The Effect of Temporal Gap Identification on Speech Perception by Users of Cochlear Implants

    ERIC Educational Resources Information Center

    Sagi, Elad; Kaiser, Adam R.; Meyer, Ted A.; Svirsky, Mario A.

    2009-01-01

    Purpose: This study examined the ability of listeners using cochlear implants (CIs) and listeners with normal hearing (NH) to identify silent gaps of different duration and the relation of this ability to speech understanding in CI users. Method: Sixteen NH adults and 11 postlingually deafened adults with CIs identified synthetic vowel-like…

  2. Pediatric Cochlear Implantation: Why Do Children Receive Implants Late?

    PubMed Central

    Ham, Julia; Whittingham, JoAnne

    2015-01-01

    Objectives: Early cochlear implantation has been widely promoted for children who derive inadequate benefit from conventional acoustic amplification. Universal newborn hearing screening has led to earlier identification and intervention, including cochlear implantation in much of the world. The purpose of this study was to examine age and time to cochlear implantation and to understand the factors that affected late cochlear implantation in children who received cochlear implants. Design: In this population-based study, data were examined for all children who underwent cochlear implant surgery in one region of Canada from 2002 to 2013. Clinical characteristics were collected prospectively as part of a larger project examining outcomes from newborn hearing screening. For this study, audiologic details including age and severity of hearing loss at diagnosis, age at cochlear implant candidacy, and age at cochlear implantation were documented. Additional detailed medical chart information was extracted to identify the factors associated with late implantation for children who received cochlear implants more than 12 months after confirmation of hearing loss. Results: The median age of diagnosis of permanent hearing loss for 187 children was 12.6 (interquartile range: 5.5, 21.7) months, and the age of cochlear implantation over the 12-year period was highly variable with a median age of 36.2 (interquartile range: 21.4, 71.3) months. A total of 118 (63.1%) received their first implant more than 12 months after confirmation of hearing loss. Detailed analysis of clinical profiles for these 118 children revealed that late implantation could be accounted for primarily by progressive hearing loss (52.5%), complex medical conditions (16.9%), family indecision (9.3%), geographical location (5.9%), and other miscellaneous known (6.8%) and unknown factors (8.5%). Conclusions: This study confirms that despite the trend toward earlier implantation, a substantial number of children

  3. Piezosurgery in implant dentistry

    PubMed Central

    Stübinger, Stefan; Stricker, Andres; Berg, Britt-Isabelle

    2015-01-01

    Piezosurgery, or the use of piezoelectric devices, is being applied increasingly in oral and maxillofacial surgery. The main advantages of this technique are precise and selective cuttings, the avoidance of thermal damage, and the preservation of soft-tissue structures. Through the application of piezoelectric surgery, implant-site preparation, bone grafting, sinus-floor elevation, edentulous ridge splitting or the lateralization of the inferior alveolar nerve are very technically feasible. This clinical overview gives a short summary of the current literature and outlines the advantages and disadvantages of piezoelectric bone surgery in implant dentistry. Overall, piezoelectric surgery is superior to other methods that utilize mechanical instruments. Handling of delicate or compromised hard- and soft-tissue conditions can be performed with less risk for the patient. With respect to current and future innovative surgical concepts, piezoelectric surgery offers a wide range of new possibilities to perform customized and minimally invasive osteotomies. PMID:26635486

  4. Sterilisation of implantable devices.

    PubMed

    Matthews, I P; Gibson, C; Samuel, A H

    1994-01-01

    The pathogenesis and rates of infection associated with the use of a wide variety of implantable devices are described. The multi-factorial nature of post-operative periprosthetic infection is outlined and the role of sterilisation of devices is explained. The resistance of bacterial spores is highlighted as a problem and a full description is given of the processes of sterilisation by heat, steam, ethylene oxide, low temperature steam and formaldehyde, ionising radiation and liquid glutaraldehyde. Sterility assurance and validation are discussed in the context of biological indicators and physical/chemical indicators. Adverse effects upon the material composition of devices and problems of process control are listed. Finally, possible optimisations of the ethylene oxide process and their potential significance to the field of sterilisation of implants is explored. PMID:10172076

  5. Approaches to chemical synthetic biology.

    PubMed

    Chiarabelli, Cristiano; Stano, Pasquale; Anella, Fabrizio; Carrara, Paolo; Luisi, Pier Luigi

    2012-07-16

    Synthetic biology is first represented in terms of two complementary aspects, the bio-engineering one, based on the genetic manipulation of extant microbial forms in order to obtain forms of life which do not exist in nature; and the chemical synthetic biology, an approach mostly based on chemical manipulation for the laboratory synthesis of biological structures that do not exist in nature. The paper is mostly devoted to shortly review chemical synthetic biology projects currently carried out in our laboratory. In particular, we describe: the minimal cell project, then the "Never Born Proteins" and lastly the Never Born RNAs. We describe and critically analyze the main results, emphasizing the possible relevance of chemical synthetic biology for the progress in basic science and biotechnology.

  6. Is synthetic biology mechanical biology?

    PubMed

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  7. Synthetic Biology for Specialty Chemicals.

    PubMed

    Markham, Kelly A; Alper, Hal S

    2015-01-01

    In this review, we address recent advances in the field of synthetic biology and describe how those tools have been applied to produce a wide variety of chemicals in microorganisms. Here we classify the expansion of the synthetic biology toolbox into three different categories based on their primary function in strain engineering-for design, for construction, and for optimization. Next, focusing on recent years, we look at how chemicals have been produced using these new synthetic biology tools. Advances in producing fuels are briefly described, followed by a more thorough treatment of commodity chemicals, specialty chemicals, pharmaceuticals, and nutraceuticals. Throughout this review, an emphasis is placed on how synthetic biology tools are applied to strain engineering. Finally, we discuss organism and host strain diversity and provide a future outlook in the field.

  8. Synthetic Turf Multiplies Stadium Use.

    ERIC Educational Resources Information Center

    Leach, Richard

    1979-01-01

    The high school stadium in Flint, Michigan, once was used only for varsity football games. After the installation of synthetic turf, an average of 332 events have been staged there each year. (Author/MLF)

  9. Programming languages for synthetic biology.

    PubMed

    Umesh, P; Naveen, F; Rao, Chanchala Uma Maheswara; Nair, Achuthsankar S

    2010-12-01

    In the backdrop of accelerated efforts for creating synthetic organisms, the nature and scope of an ideal programming language for scripting synthetic organism in-silico has been receiving increasing attention. A few programming languages for synthetic biology capable of defining, constructing, networking, editing and delivering genome scale models of cellular processes have been recently attempted. All these represent important points in a spectrum of possibilities. This paper introduces Kera, a state of the art programming language for synthetic biology which is arguably ahead of similar languages or tools such as GEC, Antimony and GenoCAD. Kera is a full-fledged object oriented programming language which is tempered by biopart rule library named Samhita which captures the knowledge regarding the interaction of genome components and catalytic molecules. Prominent feature of the language are demonstrated through a toy example and the road map for the future development of Kera is also presented. PMID:22132053

  10. Programming languages for synthetic biology.

    PubMed

    Umesh, P; Naveen, F; Rao, Chanchala Uma Maheswara; Nair, Achuthsankar S

    2010-12-01

    In the backdrop of accelerated efforts for creating synthetic organisms, the nature and scope of an ideal programming language for scripting synthetic organism in-silico has been receiving increasing attention. A few programming languages for synthetic biology capable of defining, constructing, networking, editing and delivering genome scale models of cellular processes have been recently attempted. All these represent important points in a spectrum of possibilities. This paper introduces Kera, a state of the art programming language for synthetic biology which is arguably ahead of similar languages or tools such as GEC, Antimony and GenoCAD. Kera is a full-fledged object oriented programming language which is tempered by biopart rule library named Samhita which captures the knowledge regarding the interaction of genome components and catalytic molecules. Prominent feature of the language are demonstrated through a toy example and the road map for the future development of Kera is also presented.

  11. [Reaction of bone tissue elements on synthetic bioresorbable materials based on lactic and glycolic acids].

    PubMed

    Kulakov, A A; Grigor'ian, A S

    2014-01-01

    The aim of the study was to evaluate the adverse effects of synthetic polymeric bioresorbable materials based on lactic and glycolic acids on the bone tissue. The study was carried-out on 40 Wister-line rats. Four types of bioresorbable polymeric materials were implanted: PolyLactide Glycolide Acid (PLGA), Poly-L-Lactide Acid (PLLA); Poly-96L/4D-Lactide Acid (96/4 PLDLA); Poly-70L/30D-Lactide Acid (70/30 PLDLA). The results showed connective tissue formation (fibrointegration) bordering bone adjacent to implanted materials. This proved the materials to cause pathogenic influence on the bone which mechanisms are described in the article.

  12. Implants for cranioplasty.

    PubMed

    Gladstone, H B; McDermott, M W; Cooke, D D

    1995-04-01

    As long as there have been skull defects, there has been a recognized need to cover them in some way. Cranioplasty is the surgical correction of skull defects. The two major purposes of performing a cranioplasty are to protect the brain and to provide reasonable cosmesis. The two physical requirements of the implant are strength and malleability. Originally, foreign materials such as precious metals were used. Autogenous bone grafts have also achieved successful results. Over the past quarter-century, the popularization of acrylics and radiolucent metals has favored them over bone because of their ease of use, the absence of need to harvest donor bone, and, particularly, bone's tendency to resorb or scar. Yet foreign materials can cause excessive inflammation, producing a synovial membrane at the interface between the host bone and cranioplasty construct, increasing the risk of infection. Currently, hydroxyapatite-based ceramics, which may induce bone growth into the implant, are increasingly being used. Future applications will include antibiotic-impregnated implants and computer-generated models to improve the precision of cranioplasty fit and cosmesis.

  13. [Neurotology and cochlear implants].

    PubMed

    Merchán, Miguel A

    2015-05-01

    In this review we analyse cochlear implantation in terms of the fundamental aspects of the functioning of the auditory system. Concepts concerning neuronal plasticity applied to electrical stimulation in perinatal and adult deep hypoacusis are reviewed, and the latest scientific bases that justify early implantation following screening for congenital deafness are discussed. Finally, this review aims to serve as an example of the importance of fostering the sub-specialty of neurotology in our milieu, with the aim of bridging some of the gaps between specialties and thus improving both the knowledge in the field of research on auditory pathologies and in the screening of patients. The objectives of this review, targeted above all towards specialists in the field of otorhinolaryngology, are to analyse some significant neurological foundations in order to reach a better understanding of the clinical events that condition the indications and the rehabilitation of patients with cochlear implants, as well as to use this means to foster the growth of the sub-specialty of neurotology.

  14. SYNTHETIC SLING FAILURE - EVALUATIONS & RECOMMENDATIONS

    SciTech Connect

    MACKEY TC; HENDERSON CS

    2009-10-26

    The information and evaluations provided in this report were compiled to address the recurring problem of synthetic sling failure. As safety is the number one priority in all work aspects, a solution must be devised to prevent accidents from occurring. A total of thirteen cases regarding synthetic sling failure were evaluated in order to determine their causes, effects, and preventative measures. From the collected data, it was found that all cases in which the synthetic sling contacted the edge of its load resulted in sling failure. It is required that adequate synthetic sling protection devices be used to protect slings in any lift where the sling comes in direct contact with the edge or corner of its load. However, there are no consensus codes or standards stating the type, material, or purpose of the type of protective device used to protect the sling from being cut. Numerous industry standards and codes provide vague descriptions on how to protect synthetic slings. Without a clear, concise statement of how to protect synthetic slings, it is common for inadequate materials and sling protection devices to be used in an attempt to meet the intent of these requirements. The use of an inadequate sling protection device is the main cause of synthetic sling failure in all researched cases. Commercial sling protection devices come in many shapes and sizes, and have a variety of names, as well as advertised uses. 'Abrasion pads' and 'wear protectors' are two different names for products with the same intended purpose. There is no distinguishable way to determine the extent of sling protection which these devices will provide, or what specific scenarios they are made for. This creates room for error in a field where error is unacceptable. This report provides a recommended action for hoisting and rigging activities which require synthetic slings to contact a load, as well as recommended changes to industry standards which will benefit overall industry safety.

  15. Compounding in synthetic aperture imaging.

    PubMed

    Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-09-01

    A method for obtaining compound images using synthetic aperture data is investigated using a convex array transducer. The new approach allows spatial compounding to be performed for any number of angles without reducing the frame rate or temporal resolution. This important feature is an intrinsic property of how the compound images are constructed using synthetic aperture data and an improvement compared with how spatial compounding is obtained using conventional methods. The synthetic aperture compound images are created by exploiting the linearity of delay-and-sum beamformation for data collected from multiple spherical emissions to synthesize multiple transmit and receive apertures, corresponding to imaging the tissue from multiple directions. The many images are added incoherently, to produce a single compound image. Using a 192-element, 3.5-MHz, λ-pitch transducer, it is demonstrated from tissue-phantom measurements that the speckle is reduced and the contrast resolution improved when applying synthetic aperture compound imaging. At a depth of 4 cm, the size of the synthesized apertures is optimized for lesion detection based on the speckle information density. This is a performance measure for tissue contrast resolution which quantifies the tradeoff between resolution loss and speckle reduction. The speckle information density is improved by 25% when comparing synthetic aperture compounding to a similar setup for compounding using dynamic receive focusing. The cystic resolution and clutter levels are measured using a wire phantom setup and compared with conventional application of the array, as well as to synthetic aperture imaging without compounding. If the full aperture is used for synthetic aperture compounding, the cystic resolution is improved by 41% compared with conventional imaging, and is at least as good as what can be obtained using synthetic aperture imaging without compounding. PMID:23007781

  16. Superresolution and Synthetic Aperture Radar

    SciTech Connect

    DICKEY,FRED M.; ROMERO,LOUIS; DOERRY,ARMIN W.

    2001-05-01

    Superresolution concepts offer the potential of resolution beyond the classical limit. This great promise has not generally been realized. In this study we investigate the potential application of superresolution concepts to synthetic aperture radar. The analytical basis for superresolution theory is discussed. The application of the concept to synthetic aperture radar is investigated as an operator inversion problem. Generally, the operator inversion problem is ill posed. A criterion for judging superresolution processing of an image is presented.

  17. Modification of inflammatory response to implanted biomedical materials in vivo by surface bound superoxide dismutase mimics.

    PubMed

    Udipi, K; Ornberg, R L; Thurmond, K B; Settle, S L; Forster, D; Riley, D

    2000-09-15

    The healing response to implanted biomedical materials involves varying degrees and stages of inflammation and healing which in some cases leads to device failure. In this article, we describe synthetic methods and in vivo results of a novel surface treatment for biomedical materials involving covalent conjugation of a low molecular weight superoxide dismutase mimic (SODm), which imparts anti-inflammatory character to the material. SODm investigated in this study are a new class of anti-inflammatory drugs consisting of a Mn(II) complex of a macrocyclic polyamine ring that catalyze the dismutation of superoxide at rates equivalent to that of native enzyme. The SODms were covalently linked to small disks of ultra-high molecular weight polyethylene, poly(etherurethane urea), and tantalum metal at two concentrations and implanted in a subcutaneous rat implant model for 3, 7, 14, and 28 days. Histological examination of the implant tissue performed at 3 and 28 days revealed striking anti-inflammatory effects on both acute and chronic inflammatory responses. At 3 days, the formation of a neutrophil-rich acute inflammatory infiltrate seen in control implants was inhibited for all three materials treated with SODm. At 28 days, foreign body giant cell formation (number of FBGCs per field) and fibrous capsule formation (mean thickness of implant capsule) were also significantly inhibited over untreated control implants. A mechanism based on our current understanding of superoxide as an inflammatory mediator at implanted biomedical materials is proposed.

  18. Synthetic biology as red herring.

    PubMed

    Preston, Beth

    2013-12-01

    It has become commonplace to say that with the advent of technologies like synthetic biology the line between artifacts and living organisms, policed by metaphysicians since antiquity, is beginning to blur. But that line began to blur 10,000 years ago when plants and animals were first domesticated; and has been thoroughly blurred at least since agriculture became the dominant human subsistence pattern many millennia ago. Synthetic biology is ultimately only a late and unexceptional offshoot of this prehistoric development. From this perspective, then, synthetic biology is a red herring, distracting us from more thorough philosophical consideration of the most truly revolutionary human practice-agriculture. In the first section of this paper I will make this case with regard to ontology, arguing that synthetic biology crosses no ontological lines that were not crossed already in the Neolithic. In the second section I will construct a parallel case with regard to cognition, arguing that synthetic biology as biological engineering represents no cognitive advance over what was required for domestication and the new agricultural subsistence pattern it grounds. In the final section I will make the case with regard to human existence, arguing that synthetic biology, even if wildly successful, is not in a position to cause significant existential change in what it is to be human over and above the massive existential change caused by the transition to agriculture. I conclude that a longer historical perspective casts new light on some important issues in philosophy of technology and environmental philosophy.

  19. Sub-meninges implantation reduces immune response to neural implants.

    PubMed

    Markwardt, Neil T; Stokol, Jodi; Rennaker, Robert L

    2013-04-15

    Glial scar formation around neural interfaces inhibits their ability to acquire usable signals from the surrounding neurons. To improve neural recording performance, the inflammatory response and glial scarring must be minimized. Previous work has indicated that meningeally derived cells participate in the immune response, and it is possible that the meninges may grow down around the shank of a neural implant, contributing to the formation of the glial scar. This study examines whether the glial scar can be reduced by placing a neural probe completely below the meninges. Rats were implanted with sets of loose microwire implants placed either completely below the meninges or implanted conventionally with the upper end penetrating the meninges, but not attached to the skull. Histological analysis was performed 4 weeks following surgical implantation to evaluate the glial scar. Our results found that sub-meninges implants showed an average reduction in reactive astrocyte activity of 63% compared to trans-meninges implants. Microglial activity was also reduced for sub-meninges implants. These results suggest that techniques that isolate implants from the meninges offer the potential to reduce the encapsulation response which should improve chronic recording quality and stability.

  20. Sub-meninges Implantation Reduces Immune Response to Neural Implants

    PubMed Central

    Markwardt, Neil T.; Stokol, Jodi; Rennaker, Robert L.

    2013-01-01

    Glial scar formation around neural interfaces inhibits their ability to acquire usable signals from the surrounding neurons. To improve neural recording performance, the inflammatory response and glial scarring must be minimized. Previous work has indicated that meningeally derived cells participate in the immune response, and it is possible that the meninges may grow down around the shank of a neural implant, contributing to the formation of the glial scar. This study examines whether the glial scar can be reduced by placing a neural probe completely below the meninges. Rats were implanted with sets of loose microwire implants placed either completely below the meninges or implanted conventionally with the upper end penetrating the meninges, but not attached to the skull. Histological analysis was performed 4 weeks following surgical implantation to evaluate the glial scar. Our results found that sub-meninges implants showed an average reduction in reactive astrocyte activity of 63% compared to trans-meninges implants. Microglial activity was also reduced for sub-meninges implants. These results suggest that techniques that isolate implants from the meninges offer the potential to reduce the encapsulation response which should improve chronic recording quality and stability. PMID:23370311

  1. Synthetic Eelgrass Oil Barrier

    NASA Astrophysics Data System (ADS)

    Curtis, T. G.

    2013-05-01

    Although surviving in situ micro-organisms eventually consume spilled oil, extensive inundation of shore biota by oil requires cleanup to enable ecological recovery within normal time scales. Although effective in calm seas and quiet waters, oil is advected over and under conventional curtain oil booms by wave actions and currents when seas are running. Most sorbent booms are not reusable, and are usually disposed of in landfills, creating excessive waste. A new concept is proposed for a floating oil barrier, to be positioned off vulnerable coasts, to interdict, contain, and sequester spilled oil, which can then be recovered and the barrier reused. While conventional oil boom designs rely principally on the immiscibility of oil in water and its relative buoyancy, the new concept barrier avoids the pitfalls of the former by taking advantage of the synergistic benefits of numerous fluid and material properties, including: density, buoyancy, elasticity, polarity, and surface area to volume ratio. Modeled after Zostera marina, commonly called eelgrass, the new barrier, referred to as synthetic eelgrass (SE), behaves analogously. Eelgrass has very long narrow, ribbon-like, leaves which support periphyton, a complex matrix of algae and heterotrophic microbes, which position themselves there to extract nutrients from the seawater flowing past them. In an analogous fashion, oil on, or in, seawater, which comes in contact with SE, is adsorbed on the surface and sequestered there. Secured to the bottom, in shoal waters, SE rises to the surface, and, if the tide is low enough, floats on the sea surface down wind, or down current to snare floating oil. The leaves of SE, called filaments, consist of intrinsically buoyant strips of ethylene methyl acrylate, aka EMA. EMA, made of long chain, saturated, hydrocarbon molecules with nearly homogeneous electron charge distributions, is a non-polar material which is oleophilic and hydrophobic. Oil must be in close proximity to the

  2. [Professional occupation after cochlear implantation].

    PubMed

    Kós, Maria-Izabel; Degive, Colette; Boëx, Colette; Maire, Raphaël; Guyot, Jean-Philippe

    2006-10-01

    This study verifies whether cochlear implants helps deaf adults to maintain or develop their professional occupations. Sixty-seven patients received a questionnaire concerning their professional activities before and after implantation. At the time of implantation 34 were professionally active. After the implantation 29 remained active, 4 of them reporting positive developments in their careers. Five patients became inactive. The previously inactive patients remained inactive. There was no difference in auditory performances between professionally active or inactive patients. Cochlear implants enable most implanted adults to maintain and even progress in their professions. However, deafness still represents an obstacle to social integration as inactive patients who searched for a job were rejected after the job interviews. PMID:17076153

  3. Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project.

    PubMed

    Sliva, Anna; Yang, Huanming; Boeke, Jef D; Mathews, Debra J H

    2015-08-01

    First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) PROJECT is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 PROJECT: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms. PMID:26272997

  4. Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project.

    PubMed

    Sliva, Anna; Yang, Huanming; Boeke, Jef D; Mathews, Debra J H

    2015-08-01

    First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) PROJECT is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 PROJECT: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms.

  5. Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project

    PubMed Central

    Sliva, Anna; Yang, Huanming; Boeke, Jef D.; Mathews, Debra J. H.

    2015-01-01

    First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) Project is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 Project: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms. PMID:26272997

  6. The Evolution of Breast Implants.

    PubMed

    Gabriel, Allen; Maxwell, G Patrick

    2015-10-01

    Breast augmentation remains one of the most common procedures performed in the United States. However, shape, feel, safety, and longevity of the implants remain important areas of research. The data provided by manufacturers show the safety and efficacy of these medical devices. Clinicians should strive to provide ongoing data and sound science to continue to improve clinical outcomes in the future. This article explores the evolution of breast implants with special emphasis on the advancement of silicone implants.

  7. Implant biomaterials: A comprehensive review

    PubMed Central

    Saini, Monika; Singh, Yashpal; Arora, Pooja; Arora, Vipin; Jain, Krati

    2015-01-01

    Appropriate selection of the implant biomaterial is a key factor for long term success of implants. The biologic environment does not accept completely any material so to optimize biologic performance, implants should be selected to reduce the negative biologic response while maintaining adequate function. Every clinician should always gain a thorough knowledge about the different biomaterials used for the dental implants. This article makes an effort to summarize various dental bio-materials which were used in the past and as well as the latest material used now. PMID:25610850

  8. Professional occupation after cochlear implantation.

    PubMed

    Kos, M-I; Degive, C; Boex, C; Guyot, J-P

    2007-03-01

    The aims of this study were to verify whether cochlear implants helped profoundly deaf adults to maintain or even to develop their professional occupations, and to identify other elements that may contribute to or, on the contrary, impede such patients' professional success. All adult patients received a questionnaire concerning their professional activities before and after implantation. Demographic data, health information, hearing performance and degree of satisfaction with the implant were also considered. Sixty-seven adults had been implanted, with three different devices, since 1985. At the time of implantation, 34 had been professionally active. After implantation, 29 had remained professionally active, four of whom reported positive developments in their careers. Five patients had become professionally inactive. Those patients who had previously been professionally inactive remained so. There had been no difference in performance, either between different types of cochlear implants or between professionally active or inactive patients. The implanted patients had kept their jobs and many of them had developed their professional skills. In spite of this, cochlear implants may still be perceived as proving insufficiently satisfactory hearing to enable professionally inactive patients to reintegrate and to facilitate further learning or career developments. PMID:17052367

  9. Development, Characterizations and Biocompatibility Evaluations of Intravitreal Lipid Implants

    PubMed Central

    Tamaddon, Lana; Mostafavi, Abolfazl; Riazi-esfahani, Mohammad; Karkhane, Reza; Aghazadeh, Sara; Rafiee-Tehrani, Morteza; Abedin Dorkoosh, Farid; Asadi Amoli, Fahimeh

    2014-01-01

    Background: The treatment of posterior eye diseases is always challenging mainly due to inaccessibility of the region. Many drugs are currently delivered by repeated intraocular injections. Objectives: The purpose of this study was to investigate the potential applications of natural triglycerides as alternative carriers to synthetic polymers in terms of drug release profile and also biocompatibility for intraocular use. Materials and Methods: In vitro/in vivo evaluations of intravitreal implants fabricated from the physiological lipid, glyceride tripalmitate containing clindamycin phosphate as a model drug was performed. The micro-implants with average diameter of 0.4 mm were fabricated via a hot melt extrusion method. The extrudates were analyzed using scanning electron microscopy, differential scanning calorimetry, and in vitro drug dissolution studies. For biocompatibility, the implants were implanted into rabbit eyes. Clinical investigations including fundus observations, electroretinography as well as histological evaluations were performed. Results: In vitro tests guaranteed usefulness of the production method for preparing the homogenous mixture of the drug and lipid without affecting thermal and crystalinity characteristics of the components. In vitro releases indicated a bi-phasic pattern for lower lipid ratios, which were completed by the end of day three. With higher lipid ratios, more controlled release profiles were achieved until about ten days for a lipid ratio of 95%. Clinical observations did not show any abnormalities up to two months after implantation into the rabbit eye. Conclusions: These results suggest that although the implant could not adequately retard release of the present drug model yet, due to good physical characteristics and in vivo biocompatibility, it can represent a suitable device for loading wide ranges of therapeutics in treatment of many kinds of retinochoroidal disorders. PMID:24872944

  10. Control theory meets synthetic biology.

    PubMed

    Del Vecchio, Domitilla; Dy, Aaron J; Qian, Yili

    2016-07-01

    The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology. PMID:27440256

  11. Control theory meets synthetic biology.

    PubMed

    Del Vecchio, Domitilla; Dy, Aaron J; Qian, Yili

    2016-07-01

    The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology.

  12. Control theory meets synthetic biology

    PubMed Central

    2016-01-01

    The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology. PMID:27440256

  13. Content metamorphosis in synthetic holography

    NASA Astrophysics Data System (ADS)

    Desbiens, Jacques

    2013-02-01

    A synthetic hologram is an optical system made of hundreds of images amalgamated in a structure of holographic cells. Each of these images represents a point of view on a three-dimensional space which makes us consider synthetic holography as a multiple points of view perspective system. In the composition of a computer graphics scene for a synthetic hologram, the field of view of the holographic image can be divided into several viewing zones. We can attribute these divisions to any object or image feature independently and operate different transformations on image content. In computer generated holography, we tend to consider content variations as a continuous animation much like a short movie. However, by composing sequential variations of image features in relation with spatial divisions, we can build new narrative forms distinct from linear cinematographic narration. When observers move freely and change their viewing positions, they travel from one field of view division to another. In synthetic holography, metamorphoses of image content are within the observer's path. In all imaging Medias, the transformation of image features in synchronisation with the observer's position is a rare occurrence. However, this is a predominant characteristic of synthetic holography. This paper describes some of my experimental works in the development of metamorphic holographic images.

  14. Meeting Report: Synthetic Biology Jamboree for Undergraduates

    ERIC Educational Resources Information Center

    Campbell, A. Malcolm

    2005-01-01

    The field of synthetic biology (the name is derived from an analogy to synthetic chemistry) has recognized itself as a "field" only since about 2002. Synthetic biology has gotten some high-profile attention recently, but most people are not aware the field even exists. Synthetic biologists apply engineering principles to genomic circuits to…

  15. Implantable medical sensor system

    DOEpatents

    Darrow, Christopher B.; Satcher, Jr., Joe H.; Lane, Stephen M.; Lee, Abraham P.; Wang, Amy W.

    2001-01-01

    An implantable chemical sensor system for medical applications is described which permits selective recognition of an analyte using an expandable biocompatible sensor, such as a polymer, that undergoes a dimensional change in the presence of the analyte. The expandable polymer is incorporated into an electronic circuit component that changes its properties (e.g., frequency) when the polymer changes dimension. As the circuit changes its characteristics, an external interrogator transmits a signal transdermally to the transducer, and the concentration of the analyte is determined from the measured changes in the circuit. This invention may be used for minimally invasive monitoring of blood glucose levels in diabetic patients.

  16. Broad beam ion implanter

    DOEpatents

    Leung, K.N.

    1996-10-08

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes. 6 figs.

  17. Broad beam ion implanter

    DOEpatents

    Leung, Ka-Ngo

    1996-01-01

    An ion implantation device for creating a large diameter, homogeneous, ion beam is described, as well as a method for creating same, wherein the device is characterized by extraction of a diverging ion beam and its conversion by ion beam optics to an essentially parallel ion beam. The device comprises a plasma or ion source, an anode and exit aperture, an extraction electrode, a divergence-limiting electrode and an acceleration electrode, as well as the means for connecting a voltage supply to the electrodes.

  18. Computer implants and death.

    PubMed

    Gert, Bernard

    2009-01-01

    Although a patient whose whole brain has ceased to function may have his heart, lungs, and other organs continue to function if they are connected to the appropriate machines, the patient is still dead and the machines can be disconnected. In the future, nanotechnology, or other technology, may allow putting implants in the brainstem that can keep a patient's heart, lungs and other organs functioning, even though the whole natural brain has ceased to function. It would be useful to consider how this technology might affect the criterion of death before it is actually available.

  19. Bone cement implantation syndrome.

    PubMed

    Razuin, R; Effat, O; Shahidan, M N; Shama, D V; Miswan, M F M

    2013-06-01

    Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, cardiac arrhythmias, increased pulmonary vascular resistance and cardiac arrest. It is a known cause of morbidity and mortality in patients undergoing cemented orthopaedic surgeries. The rarity of the condition as well as absence of a proper definition has contributed to under-reporting of cases. We report a 59-year-old woman who sustained fracture of the neck of her left femur and underwent an elective hybrid total hip replacement surgery. She collapsed during surgery and was revived only to succumb to death twelve hours later. Post mortem findings showed multiorgan disseminated microembolization of bone marrow and amorphous cement material. PMID:23817399

  20. Transmission of acoustic emission in bones, implants and dental materials.

    PubMed

    Ossi, Zannar; Abdou, Wael; Reuben, Robert L; Ibbetson, Richard J

    2013-11-01

    There is considerable interest in using acoustic emission (AE) and ultrasound to assess the quality of implant-bone interfaces and to monitor for micro-damage leading to loosening. However, remarkably little work has been done on the transmission of ultrasonic waves though the physical and biological structures involved. The aim of this in vitro study is to assess any differences in transmission between various dental materials and bovine rib bones with various degrees of hydration. Two types of tests have been carried out using pencil lead breaks as a standard AE source. The first set of tests was configured to assess the surface propagation of AE on various synthetic materials compared with fresh bovine rib bone. The second is a set of transmission tests on fresh, dried and hydrated bones each fitted with dental implants with various degrees of fixity, which includes components due to bone and interface transmission. The results indicate that transmission through glass ionomer cement is closest to the bone. This would suggest that complete osseointegration could potentially be simulated using such cement. The transmission of AE energy through bone was found to be dependent on its degree of hydration. It was also found that perfusing samples of fresh bone with water led to an increase in transmitted energy, but this appeared to affect transmission across the interface more than transmission through the bone. These findings have implications not only for implant interface inspection but also for passive AE monitoring of implants.

  1. Designer Drugs: A Synthetic Catastrophe

    PubMed Central

    Fratantonio, James; Andrade, Lawrence; Febo, Marcelo

    2016-01-01

    Synthetic stimulants can cause hallucinations, aggressive behaviors, death and are sometimes legal. These substances are sold as plant food and bath salts that are “Not for Human Consumption”, therefore skirting the 1986 Federal Analogue Act and giving a false pretense of safety. Studies have proved that these substances are toxic, have a high abuse potential, and are becoming extremely prevalent in the United States. This creates a dilemma for law enforcement agents, hospitals, and substance use disorder treatment centers. Urine Drug Testing is utilized as a clinical diagnostic tool in substance use disorder treatment centers, and the furious pace at which new synthetic stimulants are introduced to the black market are making the detection via urine increasingly difficult. This article will discuss the prevalence, pharmacology and difficulty developing laboratory assays to detect synthetic stimulants. PMID:27617301

  2. Synthetic Peptides as Protein Mimics

    PubMed Central

    Groß, Andrea; Hashimoto, Chie; Sticht, Heinrich; Eichler, Jutta

    2016-01-01

    The design and generation of molecules capable of mimicking the binding and/or functional sites of proteins represents a promising strategy for the exploration and modulation of protein function through controlled interference with the underlying molecular interactions. Synthetic peptides have proven an excellent type of molecule for the mimicry of protein sites because such peptides can be generated as exact copies of protein fragments, as well as in diverse chemical modifications, which includes the incorporation of a large range of non-proteinogenic amino acids as well as the modification of the peptide backbone. Apart from extending the chemical and structural diversity presented by peptides, such modifications also increase the proteolytic stability of the molecules, enhancing their utility for biological applications. This article reviews recent advances by this and other laboratories in the use of synthetic protein mimics to modulate protein function, as well as to provide building blocks for synthetic biology. PMID:26835447

  3. Differential Optical Synthetic Aperture Radar

    DOEpatents

    Stappaerts, Eddy A.

    2005-04-12

    A new differential technique for forming optical images using a synthetic aperture is introduced. This differential technique utilizes a single aperture to obtain unique (N) phases that can be processed to produce a synthetic aperture image at points along a trajectory. This is accomplished by dividing the aperture into two equal "subapertures", each having a width that is less than the actual aperture, along the direction of flight. As the platform flies along a given trajectory, a source illuminates objects and the two subapertures are configured to collect return signals. The techniques of the invention is designed to cancel common-mode errors, trajectory deviations from a straight line, and laser phase noise to provide the set of resultant (N) phases that can produce an image having a spatial resolution corresponding to a synthetic aperture.

  4. Synthetic neurosteroids on brain protection

    PubMed Central

    Rey, Mariana; Coirini, Héctor

    2015-01-01

    Neurosteroids, like allopregnanolone and pregnanolone, are endogenous regulators of neuronal excitability. Inside the brain, they are highly selective and potent modulators of GABAA receptor activity. Their anticonvulsant, anesthetics and anxiolytic properties are useful for the treatments of several neurological and psychiatric disorders via reducing the risks of side effects obtained with the commercial drugs. The principal disadvantages of endogenous neurosteroids administration are their rapid metabolism and their low oral bioavailability. Synthetic steroids analogues with major stability or endogenous neurosteroids stimulation synthesis might constitute promising novel strategies for the treatment of several disorders. Numerous studies indicate that the 3α-hydroxyl configuration is the key for binding and activity, but modifications in the steroid nucleus may emphasize different pharmacophores. So far, several synthetic steroids have been developed with successful neurosteroid-like effects. In this work, we summarize the properties of various synthetic steroids probed in trials throughout the analysis of several neurosteroids-like actions. PMID:25788907

  5. US Competitiveness in Synthetic Biology.

    PubMed

    Gronvall, Gigi Kwik

    2015-01-01

    Synthetic biology is an emerging technical field that aims to make biology easier to engineer; the field has applications in strategically important sectors for the US economy. While the United States currently leads in synthetic biology R&D, other nations are heavily investing in order to boost their economies, which will inevitably diminish the US leadership position. This outcome is not entirely negative--additional investments will expand markets--but it is critical that the US government take steps to remain competitive: There are applications from which the US population and economy may benefit; there are specific applications with importance for national defense; and US technical leadership will ensure that US experts have a leading role in synthetic biology governance, regulation, and oversight. Measures to increase competitiveness in S&T generally are broadly applicable for synthetic biology and should be pursued. However, the US government will also need to take action on fundamental issues that will affect the field's development, such as countering anti-GMO (genetically modified organism) sentiments and anti-GMO legislation. The United States should maintain its regulatory approach so that it is the product that is regulated, not the method used to create a product. At the same time, the United States needs to ensure that the regulatory framework is updated so that synthetic biology products do not fall into regulatory gaps. Finally, the United States needs to pay close attention to how synthetic biology applications may be governed internationally, such as through the Nagoya Protocol of the Convention on Biological Diversity, so that beneficial applications may be realized. PMID:26690379

  6. US Competitiveness in Synthetic Biology.

    PubMed

    Gronvall, Gigi Kwik

    2015-01-01

    Synthetic biology is an emerging technical field that aims to make biology easier to engineer; the field has applications in strategically important sectors for the US economy. While the United States currently leads in synthetic biology R&D, other nations are heavily investing in order to boost their economies, which will inevitably diminish the US leadership position. This outcome is not entirely negative--additional investments will expand markets--but it is critical that the US government take steps to remain competitive: There are applications from which the US population and economy may benefit; there are specific applications with importance for national defense; and US technical leadership will ensure that US experts have a leading role in synthetic biology governance, regulation, and oversight. Measures to increase competitiveness in S&T generally are broadly applicable for synthetic biology and should be pursued. However, the US government will also need to take action on fundamental issues that will affect the field's development, such as countering anti-GMO (genetically modified organism) sentiments and anti-GMO legislation. The United States should maintain its regulatory approach so that it is the product that is regulated, not the method used to create a product. At the same time, the United States needs to ensure that the regulatory framework is updated so that synthetic biology products do not fall into regulatory gaps. Finally, the United States needs to pay close attention to how synthetic biology applications may be governed internationally, such as through the Nagoya Protocol of the Convention on Biological Diversity, so that beneficial applications may be realized.

  7. The design of synthetic genes.

    PubMed Central

    Presnell, S R; Benner, S A

    1988-01-01

    Computer programs are described that aid in the design of synthetic genes coding for proteins that are targets of a research program in site directed mutagenesis. These programs "reverse-translate" protein sequences into general nucleic acid sequences (those where codons have not yet been selected), map restriction sites into general DNA sequences, identify points in the synthetic gene where unique restriction sites can be introduced, and assist in the design of genes coding for hybrids and evolutionary intermediates between homologous proteins. Application of these programs therefore facilitates the use of modular mutagenesis to create variants of proteins, and the implementation of evolutionary guidance as a strategy for selecting mutants. PMID:2451218

  8. The Case for Synthetic Injectables.

    PubMed

    Joseph, John H

    2015-11-01

    There are several different classes of synthetic dermal fillers and volume enhancers including semipermanent and permanent products available in the United States. Based on clinical and scientific evidence, this article reviews the chemical and polymeric properties, clinical data, patient selection, indications for use, injection technique, and adverse event profiles of permanent synthetic injectables currently used in clinical practice in the United States: medical-grade liquid injectable silicone and polymethyl methacrylate. Understanding the unique characteristics of these two products reinforces the advantages and disadvantages of each, including under what circumstances they should be used and why they perform the way they do. PMID:26505540

  9. Synthetic biology in cellular immunotherapy

    PubMed Central

    Chakravarti, Deboki; Wong, Wilson W.

    2015-01-01

    The adoptive transfer of genetically engineered T cells with cancer-targeting receptors has shown tremendous promise for eradicating tumors in clinical trials. This form of cellular immunotherapy presents a unique opportunity to incorporate advanced systems and synthetic biology approaches to create cancer therapeutics with novel functions. Here, we first review the development of synthetic receptors, switches, and circuits to control the location, duration, and strength of T cell activity against tumors. In addition, we discuss the cellular engineering and genome editing of host cells (or the chassis) to improve the efficacy of cell-based cancer therapeutics, and to reduce the time and cost of manufacturing. PMID:26088008

  10. The Case for Synthetic Injectables.

    PubMed

    Joseph, John H

    2015-11-01

    There are several different classes of synthetic dermal fillers and volume enhancers including semipermanent and permanent products available in the United States. Based on clinical and scientific evidence, this article reviews the chemical and polymeric properties, clinical data, patient selection, indications for use, injection technique, and adverse event profiles of permanent synthetic injectables currently used in clinical practice in the United States: medical-grade liquid injectable silicone and polymethyl methacrylate. Understanding the unique characteristics of these two products reinforces the advantages and disadvantages of each, including under what circumstances they should be used and why they perform the way they do.

  11. Synthetic Phage for Tissue Regeneration

    PubMed Central

    Merzlyak, Anna; Lee, Seung-Wuk

    2014-01-01

    Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy. PMID:24991085

  12. The Implantable Cardiac Pacemaker

    PubMed Central

    Trimble, A. S.; Heimbecker, R. O.; Bigelow, W. G.

    1964-01-01

    The transistorized implanted pacemaker is proving to be an effective and reliable method for long-term pacing of the heart. All patients suffering from Stokes-Adams seizures were first given a trial period of conservative therapy, including isoproterenol (Isuprel), ephedrine, atropine and steroids. Twenty-four pacemaker implants were performed on 23 patients over a 21-month period. The preoperative insertion of a pacemaker cardiac catheter was a very valuable safety precaution. In this way the heart could be safely and reliably paced during the period of preoperative assessment and during the critical periods of anesthetic induction and thoracotomy. Infection did not occur, probably because of careful gas sterilization of the units. Various models of pacemakers are compared, and the reasons for two pacemaker failures are presented. There were two early deaths and one late death in the series. The relationship of progressive coronary disease to recent infarction is stressed. Patients having intermittent heart block frequently showed the picture of “competing pacemakers” postoperatively, but without deleterious effect. Twenty patients, between 54 and 88 years of age, are alive and well at the time of reporting, with excellent pacemaker response and no further Stokes-Adams attacks. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6 PMID:14118681

  13. Transcatheter aortic valve implantation.

    PubMed

    Kapadia, Samir R; Tuzcu, E Murat

    2009-12-01

    Aortic stenosis is the most important valvular heart disease affecting the elderly population. Surgical aortic valve replacement is the mainstay of treatment, although a substantial number of patients are considered high risk for surgery. Many of these patients do not undergo surgery and have poor outcomes from medically treated symptomatic, severe aortic stenosis. Transcatheter aortic valve implantation (TAVI) provides a promising treatment option for some of these patients. Several devices are under investigation. The Edwards Sapien valve (Edwards Lifesciences, Irvine, CA) and the CoreValve (Medtronic, Minneapolis, MN) have the largest human experience to date. Initial data suggest that these devices have an acceptable safety profile and provide excellent hemodynamic relief of aortic stenosis. The Edwards Sapien valve is currently under investigation in the United States in the PARTNER (Placement of Aortic Transcatheter Valve) trial in high-risk surgical or inoperable patients; TAVI is available for clinical use in both Canada and Europe. TAVI is not used in low- or intermediate-risk surgical patients; however, future studies may prove its applicability in these subsets. The major complications of TAVI include access site-related problems and device malpositioning/migration. There are several new-generation prosthetic valves and delivery systems designed to be low profile and repositionable. Technical advances and refinement of the implantation methods may make TAVI even safer and ultimately a better treatment option, not only for patients with high surgical risk but also for those with moderate or low risk.

  14. Porous metal for orthopedics implants

    PubMed Central

    Matassi, Fabrizio; Botti, Alessandra; Sirleo, Luigi; Carulli, Christian; Innocenti, Massimo

    2013-01-01

    Summary Porous metal has been introduced to obtain biological fixation and improve longevity of orthopedic implants. The new generation of porous metal has intriguing characteristics that allows bone healing and high osteointegration of the metallic implants. This article gives an overview about biomaterials properties of the contemporary class of highly porous metals and about the clinical use in orthopaedic surgery. PMID:24133527

  15. Implant Maintenance: A Clinical Update

    PubMed Central

    Gulati, Minkle; Govila, Vivek; Anand, Vishal; Anand, Bhargavi

    2014-01-01

    Introduction. The differences in the supporting structure of the implant make them more susceptible to inflammation and bone loss when plaque accumulates as compared to the teeth. Therefore, a comprehensive maintenance protocol should be followed to ensure the longevity of the implant. Material and Method. A research to provide scientific evidence supporting the feasibility of various implant care methods was carried out using various online resources to retrieve relevant studies published since 1985. Results. The electronic search yielded 708 titles, out of which a total of 42 articles were considered appropriate and finally included for the preparation of this review article. Discussion. A typical maintenance visit for patients with dental implants should last 1 hour and should be scheduled every 3 months to evaluate any changes in their oral and general history. It is essential to have a proper instrument selection to prevent damage to the implant surface and trauma to the peri-implant tissues. Conclusion. As the number of patients opting for dental implants is increasing, it becomes increasingly essential to know the differences between natural teeth and implant care and accept the challenges of maintaining these restorations. PMID:27437506

  16. Awake transapical aortic valve implantation.

    PubMed

    Petridis, Francesco Dimitri; Savini, Carlo; Castelli, Andrea; Di Bartolomeo, Roberto

    2012-05-01

    Transapical aortic valve implantation is being employed as a less invasive alternative to open heart surgery in high-risk patients with severe aortic stenosis. Here we report the case of an awake transapical aortic valve implantation in a patient with severe chronic obstructive pulmonary disease.

  17. Photonic technologies for visual implants

    NASA Astrophysics Data System (ADS)

    Buss, Ruediger; Praemassing, F.; Puettjer, D.; Stawski, N.; Jaeger, Dieter

    2003-02-01

    In this paper two applications of photonic technologies for visual implants in the field of medicine are presented. Both are technical systems working as vision aid for people suffering from blindness due to damages in their visual system. The first system is a retinal implant (RI), the second an intraocular vision aid (IoVA) for people with opaque cornea.

  18. Regenerative Surgical Treatment of Peri-implantitis

    ClinicalTrials.gov

    2016-08-31

    Failure of Dental Implant Due to Infection; Infection; Inflammation; Peri-implantitis; Bacterial Infections; Bleeding of Subgingival Space; Molecular Sequence Variation; Periodontal Diseases; Mouth Diseases

  19. Evaluation of Hi-Tec Implant Restoration in Mandibular First Molar Region- A Prospective Clinical Study

    PubMed Central

    Sreeram, Roopa Rani. S.; Prasad, L Krishna; Chakravarthi, P Srinivas; Devi, Naga Neelima; Sreeram, Sanjay Krishna

    2015-01-01

    Background and Aims Missing teeth lead to loss of structural balance, inefficient function, poor aesthetics and psychological effects on human beings, which needs restoration for normal contour, function and aesthetics. Several natural or synthetic substitutes are being used for replacement of missing tooth since centuries. Implants are the latest modality of replacement. So, the study was aimed to assess clinical success rate of Hi-Tec implant; which is economical and new in market. Results of the study will help clinician for appropriate implant selection. Materials and Methods The study included 10 patients from 19 to 31 years and needed restoration of missing mandibular first molar. Restoration had done using Hi Tec Single-tooth implants with metal-ceramic single crown prosthesis after three months of osseointegration. The implants were evaluated clinically (bleeding on probing, probing depth, implant mobility- periotest) and radiographically (marginal bone loss and peri-implant radiolucency) for six years. The observers were blinded for the duration of the study to prevent bias. Results All the patients had uneventful post-surgical healing. No bleeding on probing, Implant mobility, peri-implant radiolucency with minimal marginal bone loss and constant probing depths were observed well within the normal range during follow-up periods. Conclusion Two stage single-tooth Hi Tec implant restoration can be used as a successful treatment modality for replacing mandibular first molar in an economic way. However, these results were obtained after 6 years of follow up with a smaller sample size, so long term multi center studies with a larger sample size is recommended for the predictability of success rate conclusively. PMID:26436053

  20. [Dental implants in tooth grinders].

    PubMed

    Lobbezoo, F; Brouwers, J E; Cune, M S; Naeije, M

    2004-03-01

    Bruxism (tooth grinding and clenching) is generally considered a contraindication for dental implants, although the evidence is usually based on clinical experience only. So far, studies to the possible cause-and-effect relationship between bruxism and implant failure do not yield consistent and specific outcomes. This is partly due to the large variation in the technical and the biological aspects of the investigations. Although there is still no proof that bruxism causes overload of dental implants and their suprastructures, a careful approach is recommended. Practical advices as to minimize the chance of implant failure are given. Besides the recommendation to reduce or eliminate bruxism itself, these advices concern the number and dimensions of the implants, the design of the occlusion and articulation patterns, and the use of a hard nightguard. PMID:15058243

  1. Nanomaterials and synergistic low intensity direct current (LIDC) stimulation technology for orthopaedic implantable medical devices

    PubMed Central

    Samberg, Meghan E.; Cohen, Paul H.; Wysk, Richard A.; Monteiro-Riviere, Nancy A.

    2012-01-01

    Nanomaterials play a significant role in biomedical research and applications due to their unique biological, mechanical, and electrical properties. In recent years, they have been utilised to improve the functionality and reliability of a wide range of implantable medical devices ranging from well-established orthopaedic residual hardware devices (e.g. hip implants) that can repair defects in skeletal systems to emerging tissue engineering scaffolds that can repair or replace organ functions. This review summarizes the applications and efficacies of these nanomaterials that include synthetic or naturally occurring metals, polymers, ceramics, and composites in orthopaedic implants, the largest market segment of implantable medical devices. The importance of synergistic engineering techniques that can augment or enhance the performance of nanomaterial applications in orthopaedic implants is also discussed,, the focus being on a low intensity direct electric current (LIDC) stimulation technology to promote the long-term antibacterial efficacy of oligodynamic metal-based surfaces by ionization, while potentially accelerating tissue growth and osseointegration. While many nanomaterials have clearly demonstrated their ability to provide more effective implantable medical surfaces, further decisive investigations are necessary before they can translate into medically safe and commercially viable clinical applications. The paper concludes with a discussion about some of the critical impending issues with the application of nanomaterials-based technologies in implantable medical devices, and potential directions to address these. PMID:23335493

  2. Comparison of Lyophilized Glutaraldehyde-Preserved Bovine Pericardium with Different Vascular Prostheses for Use as Vocal Cords Implants: Experimental Study

    PubMed Central

    Olmos-Zuñiga, J. Raúl; Jasso-Victoria, Rogelio; Gaxiola-Gaxiola, Miguel; Sotres-Vega, Avelina; Hernández-Jiménez, Claudia; Baltazares-Lipp, Matilde; Arredondo del Bosque, Fernando; Santillan-Doherty, Patricio

    2015-01-01

    This study compared the use of lyophilized glutaraldehyde-preserved bovine pericardium (LGPBP), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and Teflon felt (TF) as implants for vocal cords (VC) medialization and aimed to assess the endoscopic, macroscopic, and microscopic VC changes after medialization in a canine model. In 18 mongrel dogs, the right VC were medialized with LGPBP and the left were implanted as follows: Group I (n = 6): LGPBP and PTFE; Group II (n = 6): LGPBP and PET; Group III (n = 6): LGPBP and TF. Surgical handling of the implants was compared. Three months after surgery, macroscopic and microscopic changes of VC and implants were evaluated. LGPBP offered the best surgical handling (p = 0.005, Kruskal-Wallis). TF implants showed extrusion (p = 0.005, Kruskal-Wallis) and severe inflammation. All VC formed fibrous capsules around the implants; the ones developed by LGPBP implants were thinner (p = 0.001, ANOVA, Tukey). VC implanted with synthetic materials showed eosinophilic infiltration (p = 0.01, Kruskal-Wallis). We concluded that the LGPBP could be used as an implant for VC medialization because it is biocompatible, easy to handle and remove during surgical procedures, and nonabsorbable or extrudable and produces an inflammatory reaction similar to PTFE and PET. PMID:26075232

  3. Comparison of lyophilized glutaraldehyde-preserved bovine pericardium with different vascular prostheses for use as vocal cords implants: experimental study.

    PubMed

    Olmos-Zuñiga, J Raúl; Jasso-Victoria, Rogelio; Gaxiola-Gaxiola, Miguel; Sotres-Vega, Avelina; Hernández-Jiménez, Claudia; Baltazares-Lipp, Matilde; Arredondo del Bosque, Fernando; Santillan-Doherty, Patricio

    2015-01-01

    This study compared the use of lyophilized glutaraldehyde-preserved bovine pericardium (LGPBP), polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and Teflon felt (TF) as implants for vocal cords (VC) medialization and aimed to assess the endoscopic, macroscopic, and microscopic VC changes after medialization in a canine model. In 18 mongrel dogs, the right VC were medialized with LGPBP and the left were implanted as follows: Group I (n = 6): LGPBP and PTFE; Group II (n = 6): LGPBP and PET; Group III (n = 6): LGPBP and TF. Surgical handling of the implants was compared. Three months after surgery, macroscopic and microscopic changes of VC and implants were evaluated. LGPBP offered the best surgical handling (p = 0.005, Kruskal-Wallis). TF implants showed extrusion (p = 0.005, Kruskal-Wallis) and severe inflammation. All VC formed fibrous capsules around the implants; the ones developed by LGPBP implants were thinner (p = 0.001, ANOVA, Tukey). VC implanted with synthetic materials showed eosinophilic infiltration (p = 0.01, Kruskal-Wallis). We concluded that the LGPBP could be used as an implant for VC medialization because it is biocompatible, easy to handle and remove during surgical procedures, and nonabsorbable or extrudable and produces an inflammatory reaction similar to PTFE and PET. PMID:26075232

  4. Speech Production Intelligibility of Early Implanted Pediatric Cochlear Implant Users

    PubMed Central

    Habib, Mirette G.; Waltzman, Susan B.; Tajudeen, Bobby; Svirsky, Mario A.

    2010-01-01

    Objectives To investigate the influence of age, and age at implantation, on speech production intelligibility in prelingually deaf pediatric cochlear implant recipients. Methods Forty prelingually, profoundly deaf children who received cochlear implants between 8 and 40 months of age. Their age at testing ranged between 2.5 – 18 years. Children were recorded repeating the ten sentences in the Beginner’s Intelligibility Test. These recordings were played back to normal-hearing listeners who were unfamiliar with deaf speech and who were instructed to write down what they heard. They also rated each subject for the intelligibility of their speech production on a 5-point rating scale. The main outcome measures were the percentage of target words correctly transcribed, and the intelligibility ratings, in both cases averaged across three normal-hearing listeners. Results The data showed a strong effect of age at testing, with older children being more intelligible. This effect was particularly pronounced for children implanted in the first 24 months of life, all of whom had speech production intelligibility scores of 80% or higher when they were tested at age 5.5 years or older. This was true for only five out of nine children implanted at age 25 to 36 months. Conclusions Profoundly deaf children who receive cochlear implants in the first two years of life produce highly intelligible speech before age 6. This is also true for most, but not all children implanted in their third year. PMID:20472308

  5. Methods for preparing synthetic freshwaters.

    PubMed

    Smith, E J; Davison, W; Hamilton-Taylor, J

    2002-03-01

    Synthetic solutions that emulate the major ion compositions of natural waters are useful in experiments aimed at understanding biogeochemical processes. Standard recipes exist for preparing synthetic analogues of seawater, with its relatively constant composition, but, due to the diversity of freshwaters, a range of compositions and recipes is required. Generic protocols are developed for preparing synthetic freshwaters of any desired composition. The major problems encountered in preparing hard and soft waters include dissolving sparingly soluble calcium carbonate, ensuring that the ionic components of each concentrated stock solution cannot form an insoluble salt and dealing with the supersaturation of calcium carbonate in many hard waters. For acidic waters the poor solubility of aluminium salts requires attention. These problems are overcome by preparing concentrated stock solutions according to carefully designed reaction paths that were tested using a combination of experiment and equilibrium modeling. These stock solutions must then be added in a prescribed order to prepare a final solution that is brought into equilibrium with the atmosphere. The example calculations for preparing hard, soft and acidic freshwater surrogates with major ion compositions the same as published analyses, are presented in a generalized fashion that should allow preparation of any synthetic freshwater according to its known analysis. PMID:11902783

  6. Where Synthetic Biology Meets ET

    NASA Technical Reports Server (NTRS)

    Rothschild, Lynn J.

    2016-01-01

    Synthetic biology - the design and construction of new biological parts and systems and the redesign of existing ones for useful purposes - has the potential to transform fields from pharmaceuticals to fuels. Our lab has focused on the potential of synthetic biology to revolutionize all three major parts of astrobiology: Where do we come from? Where are we going? and Are we alone? For the first and third, synthetic biology is allowing us to answer whether the evolutionary narrative that has played out on planet earth is likely to have been unique or universal. For example, in our lab we are re-evolving the biosynthetic pathways of amino acids in order to understand potential capabilities of an early organism with a limited repertoire of amino acids and developing techniques for the recovery of metals from spent electronics on other planetary bodies. And what about the limits for life? Can we create organisms that expand the envelope for life? In the future synthetic biology will play an increasing role in human activities both on earth, in fields as diverse as human health and the industrial production of novel bio-composites. Beyond earth, we will rely increasingly on biologically-provided life support, as we have throughout our evolutionary history. In order to do this, the field will build on two of the great contributions of astrobiology: studies of the origin of life and life in extreme environments.

  7. Digital 'faces' of synthetic biology.

    PubMed

    Friedrich, Kathrin

    2013-06-01

    In silicio design plays a fundamental role in the endeavour to synthesise biological systems. In particular, computer-aided design software enables users to manage the complexity of biological entities that is connected to their construction and reconfiguration. The software's graphical user interface bridges the gap between the machine-readable data on the algorithmic subface of the computer and its human-amenable surface represented by standardised diagrammatic elements. Notations like the Systems Biology Graphical Notation (SBGN), together with interactive operations such as drag & drop, allow the user to visually design and simulate synthetic systems as 'bio-algorithmic signs'. Finally, the digital programming process should be extended to the wet lab to manufacture the designed synthetic biological systems. By exploring the different 'faces' of synthetic biology, I argue that in particular computer-aided design (CAD) is pushing the idea to automatically produce de novo objects. Multifaceted software processes serve mutually aesthetic, epistemic and performative purposes by simultaneously black-boxing and bridging different data sources, experimental operations and community-wide standards. So far, synthetic biology is mainly a product of digital media technologies that structurally mimic the epistemological challenge to take both qualitative as well as quantitative aspects of biological systems into account in order to understand and produce new and functional entities.

  8. Synthetic Division and Matrix Factorization

    ERIC Educational Resources Information Center

    Barabe, Samuel; Dubeau, Franc

    2007-01-01

    Synthetic division is viewed as a change of basis for polynomials written under the Newton form. Then, the transition matrices obtained from a sequence of changes of basis are used to factorize the inverse of a bidiagonal matrix or a block bidiagonal matrix.

  9. Synthetic biology meets tissue engineering.

    PubMed

    Davies, Jamie A; Cachat, Elise

    2016-06-15

    Classical tissue engineering is aimed mainly at producing anatomically and physiologically realistic replacements for normal human tissues. It is done either by encouraging cellular colonization of manufactured matrices or cellular recolonization of decellularized natural extracellular matrices from donor organs, or by allowing cells to self-organize into organs as they do during fetal life. For repair of normal bodies, this will be adequate but there are reasons for making unusual, non-evolved tissues (repair of unusual bodies, interface to electromechanical prostheses, incorporating living cells into life-support machines). Synthetic biology is aimed mainly at engineering cells so that they can perform custom functions: applying synthetic biological approaches to tissue engineering may be one way of engineering custom structures. In this article, we outline the 'embryological cycle' of patterning, differentiation and morphogenesis and review progress that has been made in constructing synthetic biological systems to reproduce these processes in new ways. The state-of-the-art remains a long way from making truly synthetic tissues, but there are now at least foundations for future work. PMID:27284030

  10. SEASAT Synthetic Aperture Radar Data

    NASA Technical Reports Server (NTRS)

    Henderson, F. M.

    1981-01-01

    The potential of radar imagery from space altitudes is discussed and the advantages of radar over passive sensor systems are outlined. Specific reference is made to the SEASAT synthetic aperture radar. Possible applications include oil spill monitoring, snow and ice reconnaissance, mineral exploration, and monitoring phenomena in the urban environment.

  11. Synthetic substrates for enzyme analysis

    DOEpatents

    Bissell, E.R.; Mitchell, A.R.; Pearson, K.W.; Smith, R.E.

    1983-06-14

    Synthetic substrates are provided which may be represented as A-D. The A moiety includes an amino acid, polypeptide, or derivative. The D moiety includes 7-amino coumarin derivatives having an electron withdrawing substituent group at the 3 position carbon or fused between the 3 and 4 position carbons. No Drawings

  12. Synthetic substrates for enzyme analysis

    DOEpatents

    Bissell, Eugene R.; Mitchell, Alexander R.; Pearson, Karen W.; Smith, Robert E.

    1983-01-01

    Synthetic substrates are provided which may be represented as A-D. The A moiety thereof includes an amino acid, polypeptide, or derivative thereof. The D moiety thereof includes 7-amino coumarin derivatives having an electron withdrawing substituent group at the 3 position carbon or fused between the 3 and 4 position carbons.

  13. The synthetic biology open language.

    PubMed

    Myers, Chris; Clancy, Kevin; Misirli, Goksel; Oberortner, Ernst; Pocock, Matthew; Quinn, Jacqueline; Roehner, Nicholas; Sauro, Herbert M

    2015-01-01

    The design and construction of engineered organisms is an emerging new discipline called synthetic biology and holds considerable promise as a new technological platform. The design of biologically engineered systems is however nontrivial, requiring contributions from a wide array of disciplines. One particular issue that confronts synthetic biologists is the ability to unambiguously describe novel designs such that they can be reengineered by a third-party. For this reason, the synthetic biology open language (SBOL) was developed as a community wide standard for formally representing biological designs. A design created by one engineering team can be transmitted electronically to another who can then use this design to reproduce the experimental results. The development and the community of the SBOL standard started in 2008 and has since grown in use with now over 80 participants, including international, academic, and industrial interests. SBOL has stimulated the development of repositories and software tools to help synthetic biologists in their design efforts. This chapter summarizes the latest developments and future of the SBOL standard and its supporting infrastructure.

  14. Transcatheter aortic valve implantation.

    PubMed

    Nielsen, Hans Henrik Møller

    2012-12-01

    Transcatheter aortic valve implantation (TAVI) was introduced experimentally in 1989, based on a newly developed heart valve prosthesis - the stentvalve. The valve was invented by a Danish cardiologist named Henning Rud Andersen. The new valve was revolutionary. It was foldable and could be inserted via a catheter through an artery in the groin, without the need for heart lung machine. This allowed for a new valve implantation technique, much less invasive than conventional surgical aortic valve replacement (SAVR). Surgical aortic valve replacement is safe and improves symptoms along with survival. However, up to 1/3 of patients with aortic valve stenosis cannot complete the procedure due to frailty. The catheter technique was hoped to provide a new treatment option for these patients. The first human case was in 2002, but more widespread clinical use did not begin until 2006-2010. Today, in 2011, more than 40,000 valves have been implanted worldwide. Initially, because of the experimental character of the procedure, TAVI was reserved for patients who could not undergo SAVR due to high risk. The results in this group of patients were promising. The procedural safety was acceptable, and the patients experienced significant improvements in their symptoms. Three of the papers in this PhD-thesis are based on the outcome of TAVI at Skejby Hospital, in this high-risk population [I, II and IV]. Along with other international publications, they support TAVI as being superior to standard medical treatment, despite a high risk of prosthetic regurgitation. These results only apply to high-risk patients, who cannot undergo SAVR. The main purpose of this PhD study has been to investigate the quality of TAVI compared to SAVR, in order to define the indications for this new procedure. The article attached [V] describes a prospective clinical randomised controlled trial, between TAVI to SAVR in surgically amenable patients over 75 years of age with isolated aortic valve stenosis

  15. Chemical aspects of synthetic biology.

    PubMed

    Luisi, Pier Luigi

    2007-04-01

    Synthetic biology as a broad and novel field has also a chemical branch: whereas synthetic biology generally has to do with bioengineering of new forms of life (generally bacteria) which do not exist in nature, 'chemical synthetic biology' is concerned with the synthesis of chemical structures such as proteins, nucleic acids, vesicular forms, and other which do not exist in nature. Three examples of this 'chemical synthetic biology' approach are given in this article. The first example deals with the synthesis of proteins that do not exist in nature, and dubbed as 'the never born proteins' (NBPs). This research is related to the question why and how the protein structures existing in our world have been selected out, with the underlying question whether they have something very particular from the structural or thermodynamic point of view (for example, the folding). The NBPs are produced in the laboratory by the modern molecular biology technique, the phage display, so as to produce a very large library of proteins having no homology with known proteins. The second example of chemical synthetic biology has also to do with the laboratory synthesis of proteins, but, this time, adopting a prebiotic synthetic procedure, the fragment condensation of short peptides, where short means that they have a length that can be obtained by prebiotic methods; for example, from the condensation of N-carboxy anhydrides. The scheme is illustrated and discussed, being based on the fragment condensation catalyzed by peptides endowed with proteolitic activity. Selection during chain growth is determined by solubility under the contingent environmental conditions, i.e., the peptides which result insoluble are eliminated from further growth. The scheme is tested preliminarily with a synthetic chemical fragment-condensation method and brings to the synthesis of a 44-residues-long protein, which has no homology with known proteins, and which has a stable tertiary folding. Finally, the third

  16. Li diffusion and substitution in chemically diverse synthetic zircon

    NASA Astrophysics Data System (ADS)

    Trail, D.

    2015-12-01

    Li concentrations and 7Li/6Li ratios in zircon may potentially trace crustal recycling because continental and mantle-derived zircons yield distinct values (Ushikubo et al. 2008; Bouvier et al. 2012). To some extent, the usefulness of these differences may depend upon the retentively of Li in zircon. Cherniak and Watson (2010) measured relatively high diffusivities for Li; here we sought to discover the scenarios under which Li mobility might be inhibited by charge compensating cations. We conducted "in" diffusion experiments in synthetic Lu-doped (~5000 ppm), P-doped (~250 ppm), and nearly pure zircon following the procedure in Cherniak and Watson (2010). In separate experiments, Li was ion implanted at depth within polished Mud Tank zircon slabs to form a Gaussian Li concentration profile; the relaxed concentration profile was measured after heating the zircon slabs. In all experiments, which ranged from 920 to 650 oC, calculated diffusivities were in agreement with a previously established Arrhenius relationship calibrated on trace element poor Mud Tank zircon (Cherniak and Watson, 2010). We also conducted complementary LA-ICP-MS mapping on the surfaces of P- and Lu-doped synthetic zircon crystals after the Li diffusion results were obtained. This revealed heterogeneous though patterned correlation between Li+Lu in the near surface of the crystal (no strong patterns emerged for P+Li). And finally, we observed that synthetic sector-zoned zircon exhibits near step function Li concentration profiles - correlating with changes in the rare earth element concentrations across these sectors - which allowed us to examine Li diffusion in yet another manner. Re-heating these grains followed by LA-ICP-MS analysis revealed significant Li migration, with no detectable migration of the rare earth elements. While our experiments cannot be considered exhaustive, we have yet to find a scenario where Li mobility in synthetic zircon depends on charge compensating cations.

  17. Percutaneous Pulmonary Valve Implantation

    PubMed Central

    Lee, Hyoung-Doo

    2012-01-01

    Pulmonary regurgitation (PR) is a frequent sequelae after repair of tetralogy of Fallot, pulmonary atresia, truncus arteriosus, Rastelli and Ross operation. Due to patient growth and conduit degeneration, these conduits have to be changed frequently due to regurgitation or stenosis. However, morbidity is significant in these repeated operations. To prolong conduit longevity, bare-metal stenting in the right ventricular outflow tract (RVOT) obstruction has been performed. Stenting the RVOT can reduce the right ventricular pressure and symptomatic improvement, but it causes PR with detrimental effects on the right ventricle function and risks of arrhythmia. Percutaneous pulmonary valve implantation has been shown to be a safe and effective treatment for patients with pulmonary valve insufficiency, or stenotic RVOTs. PMID:23170091

  18. Transcatheter Aortic Valve Implantation.

    PubMed

    Malaisrie, S Chris; Iddriss, Adam; Flaherty, James D; Churyla, Andrei

    2016-05-01

    Severe aortic stenosis (AS) is a life-threatening condition when left untreated. Aortic valve replacement (AVR) is the gold standard treatment for the majority of patients; however, transcatheter aortic valve implantation/replacement (TAVI/TAVR) has emerged as the preferred treatment for high-risk or inoperable patients. The concept of transcatheter heart valves originated in the 1960s and has evolved into the current Edwards Sapien and Medtronic CoreValve platforms available for clinical use. Complications following TAVI, including cerebrovascular events, perivalvular regurgitation, vascular injury, and heart block have decreased with experience and evolving technology, such that ongoing trials studying TAVI in lower risk patients have become tenable. The multidisciplinary team involving the cardiac surgeon and cardiologist plays an essential role in patient selection, procedural conduct, and perioperative care.

  19. Implantable, multifunctional, bioresorbable optics

    PubMed Central

    Tao, Hu; Kainerstorfer, Jana M.; Siebert, Sean M.; Pritchard, Eleanor M.; Sassaroli, Angelo; Panilaitis, Bruce J. B.; Brenckle, Mark A.; Amsden, Jason J.; Levitt, Jonathan; Fantini, Sergio; Kaplan, David L.; Omenetto, Fiorenzo G.

    2012-01-01

    Advances in personalized medicine are symbiotic with the development of novel technologies for biomedical devices. We present an approach that combines enhanced imaging of malignancies, therapeutics, and feedback about therapeutics in a single implantable, biocompatible, and resorbable device. This confluence of form and function is accomplished by capitalizing on the unique properties of silk proteins as a mechanically robust, biocompatible, optically clear biomaterial matrix that can house, stabilize, and retain the function of therapeutic components. By developing a form of high-quality microstructured optical elements, improved imaging of malignancies and of treatment monitoring can be achieved. The results demonstrate a unique family of devices for in vitro and in vivo use that provide functional biomaterials with built-in optical signal and contrast enhancement, demonstrated here with simultaneous drug delivery and feedback about drug delivery with no adverse biological effects, all while slowly degrading to regenerate native tissue. PMID:23150544

  20. Implantable, multifunctional, bioresorbable optics.

    PubMed

    Tao, Hu; Kainerstorfer, Jana M; Siebert, Sean M; Pritchard, Eleanor M; Sassaroli, Angelo; Panilaitis, Bruce J B; Brenckle, Mark A; Amsden, Jason J; Levitt, Jonathan; Fantini, Sergio; Kaplan, David L; Omenetto, Fiorenzo G

    2012-11-27

    Advances in personalized medicine are symbiotic with the development of novel technologies for biomedical devices. We present an approach that combines enhanced imaging of malignancies, therapeutics, and feedback about therapeutics in a single implantable, biocompatible, and resorbable device. This confluence of form and function is accomplished by capitalizing on the unique properties of silk proteins as a mechanically robust, biocompatible, optically clear biomaterial matrix that can house, stabilize, and retain the function of therapeutic components. By developing a form of high-quality microstructured optical elements, improved imaging of malignancies and of treatment monitoring can be achieved. The results demonstrate a unique family of devices for in vitro and in vivo use that provide functional biomaterials with built-in optical signal and contrast enhancement, demonstrated here with simultaneous drug delivery and feedback about drug delivery with no adverse biological effects, all while slowly degrading to regenerate native tissue. PMID:23150544

  1. Reward-based hypertension control by a synthetic brain–dopamine interface

    PubMed Central

    Rössger, Katrin; Charpin-El Hamri, Ghislaine; Fussenegger, Martin

    2013-01-01

    Synthetic biology has significantly advanced the design of synthetic trigger-controlled devices that can reprogram mammalian cells to interface with complex metabolic activities. In the brain, the neurotransmitter dopamine coordinates communication with target neurons via a set of dopamine receptors that control behavior associated with reward-driven learning. This dopamine transmission has recently been suggested to increase central sympathetic outflow, resulting in plasma dopamine levels that correlate with corresponding brain activities. By functionally rewiring the human dopamine receptor D1 (DRD1) via the second messenger cyclic adenosine monophosphate (cAMP) to synthetic promoters containing cAMP response element-binding protein 1(CREB1)-specific cAMP-responsive operator modules, we have designed a synthetic dopamine-sensitive transcription controller that reversibly fine-tunes specific target gene expression at physiologically relevant brain-derived plasma dopamine levels. Following implantation of circuit-transgenic human cell lines insulated by semipermeable immunoprotective microcontainers into mice, the designer device interfaced with dopamine-specific brain activities and produced a systemic expression response when the animal’s reward system was stimulated by food, sexual arousal, or addictive drugs. Reward-triggered brain activities were able to remotely program peripheral therapeutic implants to produce sufficient amounts of the atrial natriuretic peptide, which reduced the blood pressure of hypertensive mice to the normal physiologic range. Seamless control of therapeutic transgenes by subconscious behavior may provide opportunities for treatment strategies of the future. PMID:24127594

  2. Microsystems Technology for Retinal Implants

    NASA Astrophysics Data System (ADS)

    Weiland, James

    2005-03-01

    The retinal prosthesis is targeted to treat age-related macular degeneration, retinitis pigmentosa, and other outer retinal degenerations. Simulations of artificial vision have predicted that 600-1000 individual pixels will be needed if a retinal prosthesis is to restore function such as reading large print and face recognition. An implantable device with this many electrode contacts will require microsystems technology as part of its design. An implantable retinal prosthesis will consist of several subsystems including an electrode array and hermetic packaging. Microsystems and microtechnology approaches are being investigated as possible solutions for these design problems. Flexible polydimethylsiloxane (PDMS) substrate electrode arrays and silicon micromachined electrode arrays are under development. Inactive PDMS electrodes have been implanted in 3 dogs to assess mechanical biocompatibility. 3 dogs were followed for 6 months. The implanted was securely fastened to the retina with a single retinal tack. No post-operative complications were evident. The array remained within 100 microns of the retinal surface. Histological evaluation showed a well preserved retina underneath the electrode array. A silicon device with electrodes suspended on micromachined springs has been implanted in 4 dogs (2 acute implants, 2 chronic implants). The device, though large, could be inserted into the eye and positioned on the retina. Histological analysis of the retina from the spring electrode implants showed that spring mounted posts penetrated the retina, thus the device will be redesigned to reduce the strength of the springs. These initial implants will provide information for the designers to make the next generation silicon device. We conclude that microsystems technology has the potential to make possible a retinal prosthesis with 1000 individual contacts in close proximity to the retina.

  3. Hardness of ion implanted ceramics

    SciTech Connect

    Oliver, W.C.; McHargue, C.J.; Farlow, G.C.; White, C.W.

    1985-01-01

    It has been established that the wear behavior of ceramic materials can be modified through ion implantation. Studies have been done to characterize the effect of implantation on the structure and composition of ceramic surfaces. To understand how these changes affect the wear properties of the ceramic, other mechanical properties must be measured. To accomplish this, a commercially available ultra low load hardness tester has been used to characterize Al/sub 2/O/sub 3/ with different implanted species and doses. The hardness of the base material is compared with the highly damaged crystalline state as well as the amorphous material.

  4. A synthetic mammalian electro-genetic transcription circuit.

    PubMed

    Weber, Wilfried; Luzi, Stefan; Karlsson, Maria; Sanchez-Bustamante, Carlota Diaz; Frey, Urs; Hierlemann, Andreas; Fussenegger, Martin

    2009-03-01

    Electric signal processing has evolved to manage rapid information transfer in neuronal networks and muscular contraction in multicellular organisms and controls the most sophisticated man-built devices. Using a synthetic biology approach to assemble electronic parts with genetic control units engineered into mammalian cells, we designed an electric power-adjustable transcription control circuit able to integrate the intensity of a direct current over time, to translate the amplitude or frequency of an alternating current into an adjustable genetic readout or to modulate the beating frequency of primary heart cells. Successful miniaturization of the electro-genetic devices may pave the way for the design of novel hybrid electro-genetic implants assembled from electronic and genetic parts.

  5. Engineering synthetic hydrogel microenvironments to instruct stem cells

    PubMed Central

    Guvendiren, Murat; Burdick, Jason A

    2013-01-01

    Advances in our understanding and ability to manipulate stem cell behavior are helping to move stem cell-based therapies toward the clinic. However, much of our knowledge has been gained from standard 2-dimensional culture systems, which often misrepresent many of the signals that stem cells receive in their native 3-dimensional environments. Fortunately, the field of synthetic hydrogels is developing to better recapitulate many of these signals to guide stem cell behavior, both as in vitro models and as delivery vehicles for in vivo implantation. These include a multitude of structural and biochemical cues that can be presented on the cellular scale, such as degradation, adhesion, mechanical signals, topography, and the presentation of growth factors, often with precise spatiotemporal control. PMID:23545441

  6. Synthetic Metal-Containing Polymers

    NASA Astrophysics Data System (ADS)

    Manners, Ian

    2004-04-01

    The development of the field of synthetic metal-containing polymers - where metal atoms form an integral part of the main chain or side group structure of a polymer - aims to create new materials which combine the processability of organic polymers with the physical or chemical characteristics associated with the metallic element or complex. This book covers the major developments in the synthesis, properties, and applications of synthetic metal-containing macromolecules, and includes chapters on the preparation and characterization of metal-containing polymers, metallocene-based polymers, rigid-rod organometallic polymers, coordination polymers, polymers containing main group metals, and also covers dendritic and supramolecular systems. The book describes both polymeric materials with metals in the main chain or side group structure and covers the literature up to the end of 2002.

  7. Synthetic cannabinoids: analysis and metabolites.

    PubMed

    Elsohly, Mahmoud A; Gul, Waseem; Wanas, Amira S; Radwan, Mohamed M

    2014-02-27

    Cannabimimetics (commonly referred to as synthetic cannabinoids), a group of compounds encompassing a wide range of chemical structures, have been developed by scientists with the hope of achieving selectivity toward one or the other of the cannabinoid receptors CB1 and CB2. The goal was to have compounds that could possess high therapeutic activity without many side effects. However, underground laboratories have used the information generated by the scientific community to develop these compounds for illicit use as marijuana substitutes. This chapter reviews the different classes of these "synthetic cannabinoids" with particular emphasis on the methods used for their identification in the herbal products with which they are mixed and identification of their metabolites in biological specimens.

  8. DNA recognition by synthetic constructs.

    PubMed

    Pazos, Elena; Mosquera, Jesús; Vázquez, M Eugenio; Mascareñas, José L

    2011-09-01

    The interaction of transcription factors with specific DNA sites is key for the regulation of gene expression. Despite the availability of a large body of structural data on protein-DNA complexes, we are still far from fully understanding the molecular and biophysical bases underlying such interactions. Therefore, the development of non-natural agents that can reproduce the DNA-recognition properties of natural transcription factors remains a major and challenging goal in chemical biology. In this review we summarize the basics of double-stranded DNA recognition by transcription factors, and describe recent developments in the design and preparation of synthetic DNA binders. We mainly focus on synthetic peptides that have been designed by following the DNA interaction of natural proteins, and we discuss how the tools of organic synthesis can be used to make artificial constructs equipped with functionalities that introduce additional properties to the recognition process, such as sensing and controllability.

  9. Synthetic microbial ecosystems for biotechnology.

    PubMed

    Pandhal, Jagroop; Noirel, Josselin

    2014-06-01

    Most highly controlled and specific applications of microorganisms in biotechnology involve pure cultures. Maintaining single strain cultures is important for industry as contaminants can reduce productivity and lead to longer "down-times" during sterilisation. However, microbes working together provide distinct advantages over pure cultures. They can undertake more metabolically complex tasks, improve efficiency and even expand applications to open systems. By combining rapidly advancing technologies with ecological theory, the use of microbial ecosystems in biotechnology will inevitably increase. This review provides insight into the use of synthetic microbial communities in biotechnology by applying the engineering paradigm of measure, model, manipulate and manufacture, and illustrate the emerging wider potential of the synthetic ecology field. Systems to improve biofuel production using microalgae are also discussed.

  10. [Imaging in silicone breast implantation].

    PubMed

    Gielens, Maaike P M; Koolen, Pieter G L; Hermens, Roland A E C; Rutten, Matthieu J C M

    2013-01-01

    Recently, there have been concerns regarding the use of breast implants from Poly Implant Prothèse (PIP, Seyne sur Mer, France) for breast augmentation due to their tendency to rupture and the possibility of having toxic contents. MRI using a specific silicone-sensitive sequence has proven to be the most sensitive and specific technique in the detection of intra- and extracapsular implant rupture. However, given its high costs, it is important that this technique is used sparingly. In this clinical lesson, we compare the sensitivity and specificity of mammography, ultrasound, CT and MRI for the detection of breast implant rupture. Based on two cases, a diagnostic approach is given in order to reduce health care costs. PMID:24252405

  11. Implants for draining neovascular glaucoma.

    PubMed Central

    Molteno, A C; Van Rooyen, M M; Bartholomew, R S

    1977-01-01

    The implant design, surgical technique, and pharmacological methods of controlling bleb fibrosis, used to treat neovascular glaucoma, are described, together with the results of 14 operations performed on 12 eyes. Images PMID:843508

  12. Hydrogen speciation in synthetic quartz

    USGS Publications Warehouse

    Aines, R.D.; Kirby, S.H.; Rossman, G.R.

    1984-01-01

    The dominant hydrogen impurity in synthetic quartz is molecular H2O. H-OH groups also occur, but there is no direct evidence for the hydrolysis of Si-O-Si bonds to yield Si-OH HO-Si groups. Molecular H2O concentrations in the synthetic quartz crystals studied range from less than 10 to 3,300 ppm (H/Si), and decrease smoothly by up to an order of magnitude with distance away from the seed. OH- concentrations range from 96 to 715 ppm, and rise smoothly with distance away from the seed by up to a factor of three. The observed OH- is probably all associated with cationic impurities, as in natural quartz. Molecular H2O is the dominant initial hydrogen impurity in weak quartz. The hydrolytic weakening of quartz may be caused by the transformation H2O + Si-O-Si ??? 2SiOH, but this may be a transitory change with the SiOH groups recombining to form H2O, and the average SiOH concentration remaining very low. Synthetic quartz is strengthened when the H2O is accumulated into fluid inclusions and cannot react with the quartz framework. ?? 1984 Springer-Verlag.

  13. Nano-enabled synthetic biology

    PubMed Central

    Doktycz, Mitchel J; Simpson, Michael L

    2007-01-01

    Biological systems display a functional diversity, density and efficiency that make them a paradigm for synthetic systems. In natural systems, the cell is the elemental unit and efforts to emulate cells, their components, and organization have relied primarily on the use of bioorganic materials. Impressive advances have been made towards assembling simple genetic systems within cellular scale containers. These biological system assembly efforts are particularly instructive, as we gain command over the directed synthesis and assembly of synthetic nanoscale structures. Advances in nanoscale fabrication, assembly, and characterization are providing the tools and materials for characterizing and emulating the smallest scale features of biology. Further, they are revealing unique physical properties that emerge at the nanoscale. Realizing these properties in useful ways will require attention to the assembly of these nanoscale components. Attention to systems biology principles can lead to the practical development of nanoscale technologies with possible realization of synthetic systems with cell-like complexity. In turn, useful tools for interpreting biological complexity and for interfacing to biological processes will result. PMID:17625513

  14. Synthetic metabolons for metabolic engineering.

    PubMed

    Singleton, Chloe; Howard, Thomas P; Smirnoff, Nicholas

    2014-05-01

    It has been proposed that enzymes can associate into complexes (metabolons) that increase the efficiency of metabolic pathways by channelling substrates between enzymes. Metabolons may increase flux by increasing the local concentration of intermediates, decreasing the concentration of enzymes needed to maintain a given flux, directing the products of a pathway to a specific subcellular location or minimizing the escape of reactive intermediates. Metabolons can be formed by relatively loose non-covalent protein-protein interaction, anchorage to membranes, and (in bacteria) by encapsulation of enzymes in protein-coated microcompartments. Evidence that non-coated metabolons are effective at channelling substrates is scarce and difficult to obtain. In plants there is strong evidence that small proportions of glycolytic enzymes are associated with the outside of mitochondria and are effective in substrate channelling. More recently, synthetic metabolons, in which enzymes are scaffolded to synthetic proteins or nucleic acids, have been expressed in microorganisms and these provide evidence that scaffolded enzymes are more effective than free enzymes for metabolic engineering. This provides experimental evidence that metabolons may have a general advantage and opens the way to improving the outcome of metabolic engineering in plants by including synthetic metabolons in the toolbox.

  15. Synthetic biology with RNA motifs.

    PubMed

    Saito, Hirohide; Inoue, Tan

    2009-02-01

    Structural motifs in naturally occurring RNAs and RNPs can be employed as new molecular parts for synthetic biology to facilitate the development of novel devices and systems that modulate cellular functions. In this review, we focus on the following: (i) experimental evolution techniques of RNA molecules in vitro and (ii) their applications for regulating gene expression systems in vivo. For experimental evolution, new artificial RNA aptamers and RNA enzymes (ribozymes) have been selected in vitro. These functional RNA molecules are likely to be applicable in the reprogramming of existing gene regulatory systems. Furthermore, they may be used for designing hypothetical RNA-based living systems in the so-called RNA world. For the regulation of gene expressions in living cells, the development of new riboswitches allows us to modulate the target gene expression in a tailor-made manner. Moreover, recently RNA-based synthetic genetic circuits have been reported by employing functional RNA molecules, expanding the repertory of synthetic biology with RNA motifs. PMID:18775792

  16. Synthetic LDL as targeted drug delivery vehicle

    DOEpatents

    Forte, Trudy M.; Nikanjam, Mina

    2012-08-28

    The present invention provides a synthetic LDL nanoparticle comprising a lipid moiety and a synthetic chimeric peptide so as to be capable of binding the LDL receptor. The synthetic LDL nanoparticle of the present invention is capable of incorporating and targeting therapeutics to cells expressing the LDL receptor for diseases associated with the expression of the LDL receptor such as central nervous system diseases. The invention further provides methods of using such synthetic LDL nanoparticles.

  17. Dental-Implantate und ihre Werkstoffe

    NASA Astrophysics Data System (ADS)

    Newesely, Heinrich

    1983-07-01

    Some new trends in materials for dental implants, which also effect in the operative techniques and implant design, are described. Advantages and shortcomings of the different material types are exemplified and correlated with their bioinert resp. bioactive functions. The practical interest in metallic implants focussed in titanium resp. oxide ceramics in the ceramic field, whereas the special goal of implant research follows from the improvement of the bioactive principle with loaded calcium phosphate implants.

  18. Cochlear implants in young children.

    PubMed

    Niparko, John K; Blankenhorn, Rebecca

    2003-01-01

    The cochlear implant is best characterized as a device that provides access to the sound environment. The device enables the hearing pathway to respond to environmental and speech sounds, providing informational cues from the surroundings and from others that may escape visual detection. As the developmental effects of a profound hearing loss are multiple, cochlear implants have been applied to ever younger children in an attempt to promote a more normal level of developmental learning through audition. In deafness, transducer elements of the inner ear fail to trigger auditory nerve afferent nerves in the presence of sound input. However, large reserves of afferent fibers exist even in the auditory nerve of a profoundly deaf patient. Furthermore, these nerve fibers retain the ability to respond to prosthetic activation. Through developmental learning in the early, formative years, auditory centers of the brain appear capable of processing information from the implant to provide speech comprehension and oral language development. Multichannel implants have replaced original single channel designs. multichannel devices enable larger percentages of recipients to recognize the spoken word without visual cues because they provide spectral information in addition to temporal and intensity cues. Testing under conditions of auditory (implant)-only input reveals significant open-set speech understanding capabilities in more than 75% of children after three years of device use. The benefit provided by implants may vary with a number of conditions including: hearing history, age of deafness onset, age at implantation, etiology of deafness, linguistic abilities, and the presence of a motivated system of support of oral language development. Patient variables should be given individual consideration in judging candidacy for a cochlear implant and in planning rehabilitative and education services after surgery and activation of the device.

  19. 21 CFR 175.250 - Paraffin (synthetic).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Paraffin (synthetic). 175.250 Section 175.250 Food....250 Paraffin (synthetic). Synthetic paraffin may be safely used as an impregnant in, coating on, or... catalytically converted to a mixture of paraffin hydrocarbons. Lower molecular-weight fractions are removed...

  20. 21 CFR 175.250 - Paraffin (synthetic).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Paraffin (synthetic). 175.250 Section 175.250 Food... for Use as Components of Coatings § 175.250 Paraffin (synthetic). Synthetic paraffin may be safely... process from carbon monoxide and hydrogen, which are catalytically converted to a mixture of...

  1. 21 CFR 175.250 - Paraffin (synthetic).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Paraffin (synthetic). 175.250 Section 175.250 Food... for Use as Components of Coatings § 175.250 Paraffin (synthetic). Synthetic paraffin may be safely... process from carbon monoxide and hydrogen, which are catalytically converted to a mixture of...

  2. 21 CFR 175.250 - Paraffin (synthetic).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Paraffin (synthetic). 175.250 Section 175.250 Food... for Use as Components of Coatings § 175.250 Paraffin (synthetic). Synthetic paraffin may be safely... process from carbon monoxide and hydrogen, which are catalytically converted to a mixture of...

  3. Different lattice geometries with a synthetic dimension

    NASA Astrophysics Data System (ADS)

    Suszalski, Dominik; Zakrzewski, Jakub

    2016-09-01

    The possibility of creating different geometries with the help of an extra synthetic dimension in optical lattices is studied. The additional linear potential together with Raman-assisted tunnelings are used to engineer well-controlled tunnelings between available states. The great flexibility of the system allows us to obtain different geometries of synthetic lattices with the possibility for adding synthetic gauge fields.

  4. Synthetic thermoelectric materials comprising phononic crystals

    DOEpatents

    El-Kady, Ihab F; Olsson, Roy H; Hopkins, Patrick; Reinke, Charles; Kim, Bongsang

    2013-08-13

    Synthetic thermoelectric materials comprising phononic crystals can simultaneously have a large Seebeck coefficient, high electrical conductivity, and low thermal conductivity. Such synthetic thermoelectric materials can enable improved thermoelectric devices, such as thermoelectric generators and coolers, with improved performance. Such synthetic thermoelectric materials and devices can be fabricated using techniques that are compatible with standard microelectronics.

  5. Ion implanted dielectric elastomer circuits

    NASA Astrophysics Data System (ADS)

    O'Brien, Benjamin M.; Rosset, Samuel; Anderson, Iain A.; Shea, Herbert R.

    2013-06-01

    Starfish and octopuses control their infinite degree-of-freedom arms with panache—capabilities typical of nature where the distribution of reflex-like intelligence throughout soft muscular networks greatly outperforms anything hard, heavy, and man-made. Dielectric elastomer actuators show great promise for soft artificial muscle networks. One way to make them smart is with piezo-resistive Dielectric Elastomer Switches (DES) that can be combined with artificial muscles to create arbitrary digital logic circuits. Unfortunately there are currently no reliable materials or fabrication process. Thus devices typically fail within a few thousand cycles. As a first step in the search for better materials we present a preliminary exploration of piezo-resistors made with filtered cathodic vacuum arc metal ion implantation. DES were formed on polydimethylsiloxane silicone membranes out of ion implanted gold nano-clusters. We propose that there are four distinct regimes (high dose, above percolation, on percolation, low dose) in which gold ion implanted piezo-resistors can operate and present experimental results on implanted piezo-resistors switching high voltages as well as a simple artificial muscle inverter. While gold ion implanted DES are limited by high hysteresis and low sensitivity, they already show promise for a range of applications including hysteretic oscillators and soft generators. With improvements to implanter process control the promise of artificial muscle circuitry for soft smart actuator networks could become a reality.

  6. Orbital implants: potential new directions.

    PubMed

    Hicks, Celia R; Morrison, David; Lou, Xia; Crawford, Geoffrey J; Gadjatsy, Adam; Constable, Ian J

    2006-11-01

    This article reviews orbital implants used to replace an eye after enucleation or evisceration. Advantages of implant placement are described, with discussion of implant and wrap material, and design features that affect clinical outcomes. Implants may be porous or nonporous, pegged for linkage with a cosmetic shell or unpegged, and may be wrapped with a covering material or tissue or unwrapped. Device shape, volume and material qualities affect tissue tolerance and the risk of exposure or extrusion. Limitations of currently available devices are discussed, with factors affecting surgeon and patient choice. Ideally, a device should be easy to insert, avoid the need for wrapping or adjunctive tissues, be light, biointegratable, comfortable after implantation and provide satisfactory orbital volume replacement, movement and cosmesis without requiring further surgery or pegging. This review briefly discusses developments in implant design and aspects of design that affect function, but is not a detailed clinical review; rather, it aims to stimulate thought on optimal design and discusses recent developments. Novel technology in the form of a prototype device with a soft, biointegratable anterior surface is described as an example of newer approaches.

  7. Nanostructured Surfaces of Dental Implants

    PubMed Central

    Bressan, Eriberto; Sbricoli, Luca; Guazzo, Riccardo; Tocco, Ilaria; Roman, Marco; Vindigni, Vincenzo; Stellini, Edoardo; Gardin, Chiara; Ferroni, Letizia; Sivolella, Stefano; Zavan, Barbara

    2013-01-01

    The structural and functional fusion of the surface of the dental implant with the surrounding bone (osseointegration) is crucial for the short and long term outcome of the device. In recent years, the enhancement of bone formation at the bone-implant interface has been achieved through the modulation of osteoblasts adhesion and spreading, induced by structural modifications of the implant surface, particularly at the nanoscale level. In this context, traditional chemical and physical processes find new applications to achieve the best dental implant technology. This review provides an overview of the most common manufacture techniques and the related cells-surface interactions and modulation. A Medline and a hand search were conducted to identify studies concerning nanostructuration of implant surface and their related biological interaction. In this paper, we stressed the importance of the modifications on dental implant surfaces at the nanometric level. Nowadays, there is still little evidence of the long-term benefits of nanofeatures, as the promising results achieved in vitro and in animals have still to be confirmed in humans. However, the increasing interest in nanotechnology is undoubted and more research is going to be published in the coming years. PMID:23344062

  8. Biomechanics of Corneal Ring Implants

    PubMed Central

    2015-01-01

    Purpose: To evaluate the biomechanics of corneal ring implants by providing a related mathematical theory and biomechanical model for the treatment of myopia and keratoconus. Methods: The spherical dome model considers the inhomogeneity of the tunica of the eye, dimensions of the cornea, lamellar structure of the corneal stroma, and asphericity of the cornea. It is used in this study for calculating a strengthening factor sf for the characterization of different ring-shaped corneal implant designs. The strengthening factor is a measure of the amount of strengthening of the cornea induced by the implant. Results: For ring segments and incomplete rings, sf = 1.0, which indicates that these implants are not able to strengthen the cornea. The intracorneal continuous complete ring (MyoRing) has a strengthening factor of up to sf = 3.2. The MyoRing is, therefore, able to strengthen the cornea significantly. Conclusions: The result of the presented biomechanical analysis of different ring-shaped corneal implant designs can explain the different postoperative clinical results of different implant types in myopia and keratoconus. PMID:26312619

  9. [Implant-associated infections - Diagnostics].

    PubMed

    Renz, N; Müller, M; Perka, C; Trampuz, A

    2016-10-01

    The diagnosis of implant-associated infections is challenging as chronic low-grade infections often only manifest as subtle clinical symptoms. Clinical evaluation, patient history, imaging, histopathological and microbiological examinations build the cornerstones of the diagnostics for implant-associated infections. New onset of pain at rest, local symptoms at the surgical site and early loosening of the prosthesis or pseudarthrosis should raise suspicion for an infection and prompt further evaluation. Percutaneous sinus tracts, purulent wound secretions and skin erosions with exposure of the implant are certain signs of implant-associated infections. Elevated C‑reactive protein levels in blood support the diagnosis of infection but are neither sufficient sensitive nor specific to confirm or exclude infection. Preoperative antibiotic therapy interferes with the diagnostic evaluation and should be avoided. In periprosthetic joint infections, joint aspiration with determination of the leukocyte count and microbiological examination is a crucial first diagnostic step. Through microbiological and histopathological examinations of intraoperative tissue samples, as well as sonication of explanted implants, the causative pathogen can be identified in most cases. In osteosynthesis-associated infections imaging plays a key role to detect non-union, infection callus, sequester, peri-implant osteolysis and extraosseous and intramedullary pathologies. In prosthetic joint infections imaging provides information about the position and stability of the prosthesis. In case of hematogenic infection seeding from a distant focus, blood cultures should be sampled, followed by a meticulous investigation of potential primary focus of infection, depending on the causative agent.

  10. Retinal implants: a systematic review.

    PubMed

    Chuang, Alice T; Margo, Curtis E; Greenberg, Paul B

    2014-07-01

    Retinal implants present an innovative way of restoring sight in degenerative retinal diseases. Previous reviews of research progress were written by groups developing their own devices. This systematic review objectively compares selected models by examining publications describing five representative retinal prostheses: Argus II, Boston Retinal Implant Project, Epi-Ret 3, Intelligent Medical Implants (IMI) and Alpha-IMS (Retina Implant AG). Publications were analysed using three criteria for interim success: clinical availability, vision restoration potential and long-term biocompatibility. Clinical availability: Argus II is the only device with FDA approval. Argus II and Alpha-IMS have both received the European CE Marking. All others are in clinical trials, except the Boston Retinal Implant, which is in animal studies. Vision restoration: resolution theoretically correlates with electrode number. Among devices with external cameras, the Boston Retinal Implant leads with 100 electrodes, followed by Argus II with 60 electrodes and visual acuity of 20/1262. Instead of an external camera, Alpha-IMS uses a photodiode system dependent on natural eye movements and can deliver visual acuity up to 20/546. Long-term compatibility: IMI offers iterative learning; Epi-Ret 3 is a fully intraocular device; Alpha-IMS uses intraocular photosensitive elements. Merging the results of these three criteria, Alpha-IMS is the most likely to achieve long-term success decades later, beyond current clinical availability. PMID:24403565

  11. [Implantable hemodynamic monitoring devices].

    PubMed

    Seifert, M; Butter, C

    2015-11-01

    Heart failure is one of the most frequent diagnoses in hospital admissions in Germany. In the majority of these admissions acute decompensation of an already existing chronic heart failure is responsible. New mostly wireless and remote strategies for monitoring, titration, adaptation and optimization are the focus for improvement of the treatment of heart failure patients and the poor prognosis. The implantation of hemodynamic monitoring devices follows the hypothesis that significant changes in hemodynamic parameters occur before the occurrence of acute decompensation requiring readmission. Three different hemodynamic monitoring devices have so far been investigated in clinical trials employing right ventricular pressure, left atrial pressure and pulmonary artery pressure monitoring. Only one of these systems, the CardioMENS™ HF monitoring system, demonstrated a significant reduction of hospitalization due to heart failure over 6 months in the CHAMPION trial. The systematic adaptation of medication in the CHAMPION trial significantly differed from the usual care of the control arm over 6 months. This direct day to day management of diuretics is currently under intensive investigation; however, further studies demonstrating a positive effect on mortality are needed before translation of this approach into guidelines. Without this evidence a further implementation of pressure monitoring into currently used devices and justification of the substantial technical and personnel demands are not warranted.

  12. Imaging of common breast implants and implant-related complications: A pictorial essay

    PubMed Central

    Shah, Amisha T; Jankharia, Bijal B

    2016-01-01

    The number of women undergoing breast implant procedures is increasing exponentially. It is, therefore, imperative for a radiologist to be familiar with the normal and abnormal imaging appearances of common breast implants. Diagnostic imaging studies such as mammography, ultrasonography, and magnetic resonance imaging are used to evaluate implant integrity, detect abnormalities of the implant and its surrounding capsule, and detect breast conditions unrelated to implants. Magnetic resonance imaging of silicone breast implants, with its high sensitivity and specificity for detecting implant rupture, is the most reliable modality to asses implant integrity. Whichever imaging modality is used, the overall aim of imaging breast implants is to provide the pertinent information about implant integrity, detect implant failures, and to detect breast conditions unrelated to the implants, such as cancer. PMID:27413269

  13. Why are mini-implants lost: The value of the implantation technique!

    PubMed Central

    Romano, Fabio Lourenço; Consolaro, Alberto

    2015-01-01

    The use of mini-implants have made a major contribution to orthodontic treatment. Demand has aroused scientific curiosity about implant placement procedures and techniques. However, the reasons for instability have not yet been made totally clear. The aim of this article is to establish a relationship between implant placement technique and mini-implant success rates by means of examining the following hypotheses: 1) Sites of poor alveolar bone and little space between roots lead to inadequate implant placement; 2) Different sites require mini-implants of different sizes! Implant size should respect alveolar bone diameter; 3) Properly determining mini-implant placement site provides ease for implant placement and contributes to stability; 4) The more precise the lancing procedures, the better the implant placement technique; 5) Self-drilling does not mean higher pressures; 6) Knowing where implant placement should end decreases the risk of complications and mini-implant loss. PMID:25741821

  14. Cochlear implantation: a biomechanical prosthesis for hearing loss.

    PubMed

    Yawn, Robert; Hunter, Jacob B; Sweeney, Alex D; Bennett, Marc L

    2015-01-01

    Cochlear implants are a medical prosthesis used to treat sensorineural deafness, and one of the greatest advances in modern medicine. The following article is an overview of cochlear implant technology. The history of cochlear implantation and the development of modern implant technology will be discussed, as well as current surgical techniques. Research regarding expansion of candidacy, hearing preservation cochlear implantation, and implantation for unilateral deafness are described. Lastly, innovative technology is discussed, including the hybrid cochlear implant and the totally implantable cochlear implant.

  15. Voxel-based registration of simulated and real patient CBCT data for accurate dental implant pose estimation

    NASA Astrophysics Data System (ADS)

    Moreira, António H. J.; Queirós, Sandro; Morais, Pedro; Rodrigues, Nuno F.; Correia, André Ricardo; Fernandes, Valter; Pinho, A. C. M.; Fonseca, Jaime C.; Vilaça, João. L.

    2015-03-01

    The success of dental implant-supported prosthesis is directly linked to the accuracy obtained during implant's pose estimation (position and orientation). Although traditional impression techniques and recent digital acquisition methods are acceptably accurate, a simultaneously fast, accurate and operator-independent methodology is still lacking. Hereto, an image-based framework is proposed to estimate the patient-specific implant's pose using cone-beam computed tomography (CBCT) and prior knowledge of implanted model. The pose estimation is accomplished in a threestep approach: (1) a region-of-interest is extracted from the CBCT data using 2 operator-defined points at the implant's main axis; (2) a simulated CBCT volume of the known implanted model is generated through Feldkamp-Davis-Kress reconstruction and coarsely aligned to the defined axis; and (3) a voxel-based rigid registration is performed to optimally align both patient and simulated CBCT data, extracting the implant's pose from the optimal transformation. Three experiments were performed to evaluate the framework: (1) an in silico study using 48 implants distributed through 12 tridimensional synthetic mandibular models; (2) an in vitro study using an artificial mandible with 2 dental implants acquired with an i-CAT system; and (3) two clinical case studies. The results shown positional errors of 67+/-34μm and 108μm, and angular misfits of 0.15+/-0.08° and 1.4°, for experiment 1 and 2, respectively. Moreover, in experiment 3, visual assessment of clinical data results shown a coherent alignment of the reference implant. Overall, a novel image-based framework for implants' pose estimation from CBCT data was proposed, showing accurate results in agreement with dental prosthesis modelling requirements.

  16. Cadaveric aorta implantation for aortic graft infection.

    PubMed

    Ali, Asad; Bahia, Sandeep S S; Ali, Tahir

    2016-01-01

    This case report describes a 73-year-old gentleman who underwent explantation of an infected prosthetic aorto-iliac graft and replacement with a cryopreserved thoracic and aorto-iliac allograft. The patient has been followed up a for more than a year after surgery and remains well. After elective tube graft repair of his abdominal aortic aneurysm (AAA) in 2003, he presented to our unit in 2012 in cardiac arrest as a result of a rupture of the distal graft suture line due to infection. After resuscitation he underwent aorto-bifemoral grafting using a cuff of the original aortic graft proximally. Distally the new graft was anastomosed to his common femoral arteries, with gentamicin beads left in situ. Post discharge the patient was kept under close surveillance with serial investigations including nuclear scanning, however it became apparent that his new graft was infected and that he would require aortic graft replacement, an operation with a mortality of at least 50%. The patient underwent the operation and findings confirmed a synthetic graft infection. This tube graft was explanted and a cryopreserved aorta was used to the refashion the abdominal aorta and its bifurcation. The operation required a return to theatre day one post operatively for a bleeding side branch, which was repaired. The patient went on to make a full recovery stepping down from the intensive therapy unit day 6 post operatively and went on to be discharged 32 days after his cryopreserved aorta implantation. PMID:27351624

  17. Synthetic Fuels Corporation's progress in aiding synthetic fuels development

    SciTech Connect

    Not Available

    1984-07-11

    It has been difficult for the Corporation to make progress toward the goals of the Energy Security Act of June 1980 because of the changing economic and energy conditions. Relative to the 1987 production goal of 500,000 barrels of crude oil equivalent per day, the Corporation had awarded contracts for two projects expected to have a total production equivalent of 9500 barrels of crude oil per day. Including these two projects, the Corporation has said that it plans to award by early 1985 up to $14.8 billion in financial assistance for about 12 projects representing a diverse range of technologies, which would have a combined total production of about 132,000 barrels of crude oil equivalent per day. These plans may be affected by a recent administration proposal to rescind $9 billion of the Corporation's remaining unobligated funds. Private industry officials said that synthetic fuels projects have been abandoned or postponed primarily because of an unfavorable economic climate, a world oil glut that has caused declines in crude oil prices, the uncertainty of future crude oil prices, and the large capital investment needed for project construction. These officials also said that 1982 tax legislation, by reducing the after-tax return on investment, has also caused industry to abandon or delay going forward with synthetic fuels projects.

  18. Biomechanical load analysis of cantilevered implant systems.

    PubMed

    Osier, J F

    1991-01-01

    Historically, dental implants have been placed in areas where quality bone exists. The maxillary sinus areas and mandibular canal proximities have been avoided. From these placements, various cantilevered prosthetic applications have emerged. This analysis uses static engineering principles to define the loads (i.e., forces) placed upon the implants. These principles make use of Newton's first and third laws of mechanics by summing the forces and moments to zero. These summations then generate mathematical equations and their algebraic solutions. Three implant systems are analyzed. The first is a two-implant system. The second is a three-implant cross-arch stabilized system usually found in mandibular replacements of lower full dentures. The third is a five-implant system which is identical to the three-implant cantilevered system but which uses implants in the first molar area, thereby negating the cantilevered load magnification of the three-implant design. These analyses demonstrate that, in a cantilevered application, the implant closest to the point of load application (usually the most posterior implant) takes the largest compressive load. Implants opposite the load application (generally the anterior implant) are in tension. These loads on the implants are normally magnified over the biting force and can easily reach 2 1/2 to five times the biting load.

  19. Materials for endosseous dental implants.

    PubMed

    Wataha, J C

    1996-02-01

    The goal of placement of endosseous dental implants is to achieve osseointegration or biointegration of the bone with the implant. A wide variety of materials has been used for these implants, but only a few promote osseointegration and biointegration. Titanium and titanium alloy (Ti6A14V) have been the most widely used of these materials. The surface oxide of titanium appears to be central to the ability of this material to osseointegrate. The oxide limits dissolution of elements and promotes the deposition of biological molecules which allow bone to exist as close as 30 A to the surface of the implant. The details of the ultrastructure of the gap between the implant and bone remain undefined, and the consequences of elements which are released on the interface over time are not known. These areas of investigation are particularly important in defining the differences between commercially pure titanium implants and those made of titanium, aluminium and vanadium. The epithelial interface between the gingiva and titanium appears to contain many of the structural characteristics of the native tooth-gingiva interface, but details are still vague. The connective tissue interface with the titanium appears to be one of tightly fitting tissues rather than adhesion. Ceramic coatings appear to improve the ingrowth of bone and promote chemical integration of the implant with the bone. The characteristics of these coatings are complex and affect the bony response, but the mechanisms remain obscure. The degradation of the coatings is an issue of particular controversy. Progress in dental implantology is likely to continue as the interface between the material and bone is more clearly understood, and biological molecules and artificial tissues are developed.

  20. Drug-eluting medical implants.

    PubMed

    Zilberman, Meital; Kraitzer, Amir; Grinberg, Orly; Elsner, Jonathan J

    2010-01-01

    Drug-eluting medical implants are actually active implants that induce healing effects, in addition to their regular task of support. This effect is achieved by controlled release of active pharmaceutical ingredients (API) into the surrounding tissue. In this chapter we focus on three types of drug-eluting devices: drug-eluting vascular stents, drug-eluting wound dressings and protein-eluting scaffolds for tissue regeneration, thus describing both internal and external implants. Each of these drug-eluting devices also presents an approach for solving the drug release issue. Most drug-eluting vascular stents are loaded with water-insoluble antiproliferative agents, and their diffusion from the device to the surrounding tissue is relatively slow. In contrast, most drug-eluting wound dressings are loaded with highly water-soluble antibacterial agents and the issue of fast release must therefore be addressed. Growth factor release from scaffolds for tissue regeneration offers a new approach of incorporating high-molecular-weight bioactive agents which are very sensitive to process conditions and preserve their activity during the preparation stage. The drug-eluting medical implants are described here in terms of matrix formats and polymers, incorporated drugs and their release profiles from the implants, and implant functioning. Basic elements, such as new composite core/shell fibers and structured films, can be used to build new antibiotic-eluting devices. As presented in this chapter, the effect of the processing parameters on the microstructure and the resulting drug release profiles, mechanical and physical properties, and other relevant properties, must be elucidated in order to achieve the desired properties. Newly developed implants and novel modifications of previously developed approaches have enhanced the tools available for creating clinically important biomedical applications.

  1. Multicomponent Implant Releasing Dexamethasone

    NASA Astrophysics Data System (ADS)

    Nikkola, L.; Vapalahti, K.; Ashammakhi, N.

    2008-02-01

    Several inflammatory conditions are usually treated with corticosteroids. There are various problems like side effects with traditional applications of steroids, e.g. topical, or systemic routes. Local drug delivery systems have been studied and developed to gain more efficient administration with fewer side effects. Earlier, we reported on developing Dexamethasone (DX) releasing biodegradable fibers. However, their drug release properties were not satisfactory in terms of onset of drug release. Thus, we assessed the development of multicomponent (MC) implant to enhance earlier drug release from such biodegradable fibers. Poly (lactide-co-glycolide) (PLGA) and 2 wt-% and 8 wt-% DX were compounded and extruded with twin-screw extruder to form of fibers. Some of the fibers were sterilized to obtain a change in drug release properties. Four different fiber classes were studied: 2 wt-%, 8 wt-%, sterilized 2 wt-%, and sterilized 8 wt-%. 3×4 different DX-releasing fibers were then heat-pressed to form one multicomponent rod. Half of the rods where sterilized. Drug release was measured from initial fibers and multicomponent rods using a UV/VIS spectrometer. Shear strength and changes in viscosity were also measured. Drug release studies showed that drug release commenced earlier from multicomponent rods than from component fibers. Drug release from multicomponent rods lasted from day 30 to day 70. The release period of sterilized rods extended from day 23 to day 57. When compared to the original component fibers, the drug release from MC rods commenced earlier. The initial shear strength of MC rods was 135 MPa and decreased to 105 MPa during four weeks of immersion in phosphate buffer solution. Accordingly, heat pressing has a positive effect on drug release. After four weeks in hydrolysis, no disintegration was observed.

  2. Interferometry with synthetic gauge fields

    SciTech Connect

    Anderson, Brandon M.; Taylor, Jacob M.; Galitski, Victor M.

    2011-03-15

    We propose a compact atom interferometry scheme for measuring weak, time-dependent accelerations. Our proposal uses an ensemble of dilute trapped bosons with two internal states that couple to a synthetic gauge field with opposite charges. The trapped gauge field couples spin to momentum to allow time-dependent accelerations to be continuously imparted on the internal states. We generalize this system to reduce noise and estimate the sensitivity of such a system to be S{approx}10{sup -7}(m/s{sup 2}/{radical}(Hz)).

  3. Synthetic Biology Guides Biofuel Production

    PubMed Central

    Connor, Michael R.; Atsumi, Shota

    2010-01-01

    The advancement of microbial processes for the production of renewable liquid fuels has increased with concerns about the current fuel economy. The development of advanced biofuels in particular has risen to address some of the shortcomings of ethanol. These advanced fuels have chemical properties similar to petroleum-based liquid fuels, thus removing the need for engine modification or infrastructure redesign. While the productivity and titers of each of these processes remains to be improved, progress in synthetic biology has provided tools to guide the engineering of these processes through present and future challenges. PMID:20827393

  4. Synthetic magnetism for photon fluids

    NASA Astrophysics Data System (ADS)

    Westerberg, N.; Maitland, C.; Faccio, D.; Wilson, K.; Öhberg, P.; Wright, E. M.

    2016-08-01

    We develop a theory of artificial gauge fields in photon fluids for the cases of both second-order and third-order optical nonlinearities. This applies to weak excitations in the presence of pump fields carrying orbital angular momentum and is thus a type of Bogoliubov theory. The resulting artificial gauge fields experienced by the weak excitations are an interesting generalization of previous cases and reflect the PT-symmetry properties of the underlying non-Hermitian Hamiltonian. We illustrate the observable consequences of the resulting synthetic magnetic fields for examples involving both second-order and third-order nonlinearities.

  5. Synthetic Studies in Phytochrome Chemistry

    PubMed Central

    Jacobi, Peter A.; Adel Odeh, Imad M.; Buddhu, Subhas C.; Cai, Guolin; Rajeswari, Sundaramoorthi; Fry, Douglas; Zheng, Wanjun; DeSimone, Robert W.; Guo, Jiasheng; Coutts, Lisa D.; Hauck, Sheila I.; Leung, Sam H.; Ghosh, Indranath; Pippin., Douglas

    2008-01-01

    An account is given of the author’s several approaches to the synthesis of the parent chromophore of phytochrome (1), a protein-bound linear tetrapyrrole derivative that controls photomorphogenesis in higher plants. These studies culminated in enantioselective syntheses of both 2R- and 2S-phytochromobilin (4), as well as several 13C-labeled derivatives designed to probe the site of Z,E-isomerization during photoexcitation. When reacted in vitro, synthetic 2R-4 and recombinant-derived phytochrome apoprotein N-C produced a protein-bound chromophore with identical difference spectra to naturally occurring 1. PMID:18633455

  6. Synthetic carbonaceous fuels and feedstocks

    DOEpatents

    Steinberg, Meyer

    1980-01-01

    This invention relates to the use of a three compartment electrolytic cell in the production of synthetic carbonaceous fuels and chemical feedstocks such as gasoline, methane and methanol by electrolyzing an aqueous sodium carbonate/bicarbonate solution, obtained from scrubbing atmospheric carbon dioxide with an aqueous sodium hydroxide solution, whereby the hydrogen generated at the cathode and the carbon dioxide liberated in the center compartment are combined thermocatalytically into methanol and gasoline blends. The oxygen generated at the anode is preferably vented into the atmosphere, and the regenerated sodium hydroxide produced at the cathode is reused for scrubbing the CO.sub.2 from the atmosphere.

  7. Medical implants and methods of making medical implants

    SciTech Connect

    Shaw, Wendy J; Yonker, Clement R; Fulton, John L; Tarasevich, Barbara J; McClain, James B; Taylor, Doug

    2014-09-16

    A medical implant device having a substrate with an oxidized surface and a silane derivative coating covalently bonded to the oxidized surface. A bioactive agent is covalently bonded to the silane derivative coating. An implantable stent device including a stent core having an oxidized surface with a layer of silane derivative covalently bonded thereto. A spacer layer comprising polyethylene glycol (PEG) is covalently bonded to the layer of silane derivative and a protein is covalently bonded to the PEG. A method of making a medical implant device including providing a substrate having a surface, oxidizing the surface and reacting with derivitized silane to form a silane coating covalently bonded to the surface. A bioactive agent is then covalently bonded to the silane coating. In particular instances, an additional coating of bio-absorbable polymer and/or pharmaceutical agent is deposited over the bioactive agent.

  8. Implantable biomedical devices on bioresorbable substrates

    DOEpatents

    Rogers, John A; Kim, Dae-Hyeong; Omenetto, Fiorenzo; Kaplan, David L; Litt, Brian; Viventi, Jonathan; Huang, Yonggang; Amsden, Jason

    2014-03-04

    Provided herein are implantable biomedical devices, methods of administering implantable biomedical devices, methods of making implantable biomedical devices, and methods of using implantable biomedical devices to actuate a target tissue or sense a parameter associated with the target tissue in a biological environment. Each implantable biomedical device comprises a bioresorbable substrate, an electronic device having a plurality of inorganic semiconductor components supported by the bioresorbable substrate, and a barrier layer encapsulating at least a portion of the inorganic semiconductor components. Upon contact with a biological environment the bioresorbable substrate is at least partially resorbed, thereby establishing conformal contact between the implantable biomedical device and the target tissue in the biological environment.

  9. Cochlear Implantation in Older Adults

    PubMed Central

    Lin, Frank R.; Chien, Wade W.; Li, Lingsheng; Niparko, John K.; Francis, Howard W.

    2012-01-01

    Cochlear implants allow individuals with severe-to-profound hearing loss access to sound and spoken language. The number of older adults in the United States who are potential candidates for cochlear implantation is approximately 150,000 and will continue to increase with the aging of the population. Should cochlear implantation (CI) be routinely recommended for these older adults, and do these individuals benefit from CI? We reviewed our 12 year experience with cochlear implantation in adults ≥60 years (n = 445) at Johns Hopkins to investigate the impact of CI on speech understanding and to identify factors associated with speech performance. Complete data on speech outcomes at baseline and 1 year post-CI were available for 83 individuals. Our results demonstrate that cochlear implantation in adults ≥60 years consistently improved speech understanding scores with a mean increase of 60. 0% (S. D. 24. 1) on HINT sentences in quiet . The magnitude of the gain in speech scores was negatively associated with age at implantation such that for every increasing year of age at CI the gain in speech scores was 1. 3 percentage points less (95% CI: 0. 6 – 1. 9) after adjusting for age at hearing loss onset. Conversely, individuals with higher pre-CI speech scores (HINT scores between 40–60%) had significantly greater post-CI speech scores by a mean of 10. 0 percentage points (95% CI: 0. 4 – 19. 6) than those with lower pre-CI speech scores (HINT <40%) after adjusting for age at CI and age at hearing loss onset. These results suggest that older adult CI candidates who are younger at implantation and with higher preoperative speech scores obtain the highest speech understanding scores after cochlear implantation with possible implications for current Medicare policy. Finally, we provide an extended discussion of the epidemiology and impact of hearing loss in older adults. Future research of CI in older adults should expand beyond simple speech outcomes to take into

  10. Human-derived and new synthetic injectable materials for soft-tissue augmentation: current status and role in cosmetic surgery.

    PubMed

    Alster, T S; West, T B

    2000-06-01

    The recent development of human-derived and new synthetic filling agents heralds a new era in soft-tissue augmentation. Many of the disadvantages of xenogenic and prior exogenous materials have been overcome with the advent of these autologous, allogeneic, and inert synthetic alternatives. Early reports using human-derived and inert exogenous filling agents have demonstrated good results and prolonged correction. It is too early, however, to assess the long-term efficacy of these agents. Future investigations should include histologic examination after facial implantation to document long-term safety and efficacy.

  11. Immunomodulation by mesenchymal stem cells combats the foreign body response to cell-laden synthetic hydrogels.

    PubMed

    Swartzlander, Mark D; Blakney, Anna K; Amer, Luke D; Hankenson, Kurt D; Kyriakides, Themis R; Bryant, Stephanie J

    2015-02-01

    The implantation of non-biological materials, including scaffolds for tissue engineering, ubiquitously leads to a foreign body response (FBR). We recently reported that this response negatively impacts fibroblasts encapsulated within a synthetic hydrogel and in turn leads to a more severe FBR, suggesting a cross-talk between encapsulated cells and inflammatory cells. Given the promise of mesenchymal stem cells (MSCs) in tissue engineering and recent evidence of their immunomodulatory properties, we hypothesized that MSCs encapsulated within poly(ethylene glycol) (PEG) hydrogels will attenuate the FBR. In vitro, murine MSCs encapsulated within PEG hydrogels attenuated classically activated primary murine macrophages by reducing gene expression and protein secretion of pro-inflammatory cytokines, most notably tumor necrosis factor-α. Using a COX2 inhibitor, prostaglandin E2 (PGE2) was identified as a mediator of MSC immunomodulation of macrophages. In vivo, hydrogels laden with MSCs, osteogenically differentiating MSCs, or no cells were implanted subcutaneously into C57BL/6 mice for 28 days to assess the impact of MSCs on the fibrotic response of the FBR. The presence of encapsulated MSCs reduced fibrous capsule thickness compared to acellular hydrogels, but this effect diminished with osteogenic differentiation. The use of MSCs prior to differentiation in tissue engineering may therefore serve as a dynamic approach, through continuous cross-talk between MSCs and the inflammatory cells, to modulate macrophage activation and attenuate the FBR to implanted synthetic scaffolds thus improving the long-term tissue engineering outcome.

  12. Capacitive Feedthroughs for Medical Implants.

    PubMed

    Grob, Sven; Tass, Peter A; Hauptmann, Christian

    2016-01-01

    Important technological advances in the last decades paved the road to a great success story for electrically stimulating medical implants, including cochlear implants or implants for deep brain stimulation. However, there are still many challenges in reducing side effects and improving functionality and comfort for the patient. Two of the main challenges are the wish for smaller implants on one hand, and the demand for more stimulation channels on the other hand. But these two aims lead to a conflict of interests. This paper presents a novel design for an electrical feedthrough, the so called capacitive feedthrough, which allows both reducing the size, and increasing the number of included channels. Capacitive feedthroughs combine the functionality of a coupling capacitor and an electrical feedthrough within one and the same structure. The paper also discusses the progress and the challenges of the first produced demonstrators. The concept bears a high potential in improving current feedthrough technology, and could be applied on all kinds of electrical medical implants, even if its implementation might be challenging.

  13. SURFACE CHEMISTRY INFLUENCE IMPLANT BIOCOMPATIBILITY

    PubMed Central

    Thevenot, Paul; Hu, Wenjing; Tang, Liping

    2011-01-01

    Implantable medical devices are increasingly important in the practice of modern medicine. Unfortunately, almost all medical devices suffer to a different extent from adverse reactions, including inflammation, fibrosis, thrombosis and infection. To improve the safety and function of many types of medical implants, a major need exists for development of materials that evoked desired tissue responses. Because implant-associated protein adsorption and conformational changes thereafter have been shown to promote immune reactions, rigorous research efforts have been emphasized on the engineering of surface property (physical and chemical characteristics) to reduce protein adsorption and cell interactions and subsequently improve implant biocompatibility. This brief review is aimed to summarize the past efforts and our recent knowledge about the influence of surface functionality on protein:cell:biomaterial interactions. It is our belief that detailed understandings of bioactivity of surface functionality provide an easy, economic, and specific approach for the future rational design of implantable medical devices with desired tissue reactivity and, hopefully, wound healing capability. PMID:18393890

  14. Capacitive Feedthroughs for Medical Implants.

    PubMed

    Grob, Sven; Tass, Peter A; Hauptmann, Christian

    2016-01-01

    Important technological advances in the last decades paved the road to a great success story for electrically stimulating medical implants, including cochlear implants or implants for deep brain stimulation. However, there are still many challenges in reducing side effects and improving functionality and comfort for the patient. Two of the main challenges are the wish for smaller implants on one hand, and the demand for more stimulation channels on the other hand. But these two aims lead to a conflict of interests. This paper presents a novel design for an electrical feedthrough, the so called capacitive feedthrough, which allows both reducing the size, and increasing the number of included channels. Capacitive feedthroughs combine the functionality of a coupling capacitor and an electrical feedthrough within one and the same structure. The paper also discusses the progress and the challenges of the first produced demonstrators. The concept bears a high potential in improving current feedthrough technology, and could be applied on all kinds of electrical medical implants, even if its implementation might be challenging. PMID:27660602

  15. Capacitive Feedthroughs for Medical Implants

    PubMed Central

    Grob, Sven; Tass, Peter A.; Hauptmann, Christian

    2016-01-01

    Important technological advances in the last decades paved the road to a great success story for electrically stimulating medical implants, including cochlear implants or implants for deep brain stimulation. However, there are still many challenges in reducing side effects and improving functionality and comfort for the patient. Two of the main challenges are the wish for smaller implants on one hand, and the demand for more stimulation channels on the other hand. But these two aims lead to a conflict of interests. This paper presents a novel design for an electrical feedthrough, the so called capacitive feedthrough, which allows both reducing the size, and increasing the number of included channels. Capacitive feedthroughs combine the functionality of a coupling capacitor and an electrical feedthrough within one and the same structure. The paper also discusses the progress and the challenges of the first produced demonstrators. The concept bears a high potential in improving current feedthrough technology, and could be applied on all kinds of electrical medical implants, even if its implementation might be challenging. PMID:27660602

  16. Capacitive Feedthroughs for Medical Implants

    PubMed Central

    Grob, Sven; Tass, Peter A.; Hauptmann, Christian

    2016-01-01

    Important technological advances in the last decades paved the road to a great success story for electrically stimulating medical implants, including cochlear implants or implants for deep brain stimulation. However, there are still many challenges in reducing side effects and improving functionality and comfort for the patient. Two of the main challenges are the wish for smaller implants on one hand, and the demand for more stimulation channels on the other hand. But these two aims lead to a conflict of interests. This paper presents a novel design for an electrical feedthrough, the so called capacitive feedthrough, which allows both reducing the size, and increasing the number of included channels. Capacitive feedthroughs combine the functionality of a coupling capacitor and an electrical feedthrough within one and the same structure. The paper also discusses the progress and the challenges of the first produced demonstrators. The concept bears a high potential in improving current feedthrough technology, and could be applied on all kinds of electrical medical implants, even if its implementation might be challenging.

  17. PROPERTIES OF DEFECTS AND IMPLANTS IN Mg+ IMPLANTED SILICON CARBIDE

    SciTech Connect

    Jiang, Weilin; Zhu, Zihua; Varga, Tamas; Bowden, Mark E.; Manandhar, Sandeep; Roosendaal, Timothy J.; Hu, Shenyang Y.; Henager, Charles H.; Kurtz, Richard J.; Wang, Yongqiang

    2013-09-25

    As a candidate material for fusion reactor designs, silicon carbide (SiC) under high-energy neutron irradiation undergoes atomic displacement damage and transmutation reactions that create magnesium as one of the major metallic products. The presence of Mg and lattice disorder in SiC is expected to affect structural stability and degrade thermo-mechanical properties that could limit SiC lifetime for service. We have initiated a combined experimental and computational study that uses Mg+ ion implantation and multiscale modeling to investigate the structural and chemical effects in Mg implanted SiC and explore possible property degradation mechanisms.

  18. Catalysts from synthetic genetic polymers.

    PubMed

    Taylor, Alexander I; Pinheiro, Vitor B; Smola, Matthew J; Morgunov, Alexey S; Peak-Chew, Sew; Cozens, Christopher; Weeks, Kevin M; Herdewijn, Piet; Holliger, Philipp

    2015-02-19

    The emergence of catalysis in early genetic polymers such as RNA is considered a key transition in the origin of life, pre-dating the appearance of protein enzymes. DNA also demonstrates the capacity to fold into three-dimensional structures and form catalysts in vitro. However, to what degree these natural biopolymers comprise functionally privileged chemical scaffolds for folding or the evolution of catalysis is not known. The ability of synthetic genetic polymers (XNAs) with alternative backbone chemistries not found in nature to fold into defined structures and bind ligands raises the possibility that these too might be capable of forming catalysts (XNAzymes). Here we report the discovery of such XNAzymes, elaborated in four different chemistries (arabino nucleic acids, ANA; 2'-fluoroarabino nucleic acids, FANA; hexitol nucleic acids, HNA; and cyclohexene nucleic acids, CeNA) directly from random XNA oligomer pools, exhibiting in trans RNA endonuclease and ligase activities. We also describe an XNA-XNA ligase metalloenzyme in the FANA framework, establishing catalysis in an entirely synthetic system and enabling the synthesis of FANA oligomers and an active RNA endonuclease FANAzyme from its constituent parts. These results extend catalysis beyond biopolymers and establish technologies for the discovery of catalysts in a wide range of polymer scaffolds not found in nature. Evolution of catalysis independent of any natural polymer has implications for the definition of chemical boundary conditions for the emergence of life on Earth and elsewhere in the Universe.

  19. Towards developing algal synthetic biology.

    PubMed

    Scaife, Mark Aden; Smith, Alison Gail

    2016-06-15

    The genetic, physiological and metabolic diversity of microalgae has driven fundamental research into photosynthesis, flagella structure and function, and eukaryotic evolution. Within the last 10 years these organisms have also been investigated as potential biotechnology platforms, for example to produce high value compounds such as long chain polyunsaturated fatty acids, pigments and antioxidants, and for biodiesel precursors, in particular triacylglycerols (TAGs). Transformation protocols, molecular tools and genome sequences are available for a number of model species including the green alga Chlamydomonas reinhardtii and the diatom Phaeodactylum tricornutum, although for both species there are bottlenecks to be overcome to allow rapid and predictable genetic manipulation. One approach to do this would be to apply the principles of synthetic biology to microalgae, namely the cycle of Design-Build-Test, which requires more robust, predictable and high throughput methods. In this mini-review we highlight recent progress in the areas of improving transgene expression, genome editing, identification and design of standard genetic elements (parts), and the use of microfluidics to increase throughput. We suggest that combining these approaches will provide the means to establish algal synthetic biology, and that application of standard parts and workflows will avoid parallel development and capitalize on lessons learned from other systems. PMID:27284033

  20. A Synthetic Multicellular Memory Device.

    PubMed

    Urrios, Arturo; Macia, Javier; Manzoni, Romilde; Conde, Núria; Bonforti, Adriano; de Nadal, Eulàlia; Posas, Francesc; Solé, Ricard

    2016-08-19

    Changing environments pose a challenge to living organisms. Cells need to gather and process incoming information, adapting to changes in predictable ways. This requires in particular the presence of memory, which allows different internal states to be stored. Biological memory can be stored by switches that retain information on past and present events. Synthetic biologists have implemented a number of memory devices for biological applications, mostly in single cells. It has been shown that the use of multicellular consortia provides interesting advantages to implement biological circuits. Here we show how to build a synthetic biological memory switch using an eukaryotic consortium. We engineered yeast cells that can communicate and retain memory of changes in the extracellular environment. These cells were able to produce and secrete a pheromone and sense a different pheromone following NOT logic. When the two strains were cocultured, they behaved as a double-negative-feedback motif with memory. In addition, we showed that memory can be effectively changed by the use of external inputs. Further optimization of these modules and addition of other cells could lead to new multicellular circuits that exhibit memory over a broad range of biological inputs. PMID:27439436

  1. The major synthetic evolutionary transitions.

    PubMed

    Solé, Ricard

    2016-08-19

    Evolution is marked by well-defined events involving profound innovations that are known as 'major evolutionary transitions'. They involve the integration of autonomous elements into a new, higher-level organization whereby the former isolated units interact in novel ways, losing their original autonomy. All major transitions, which include the origin of life, cells, multicellular systems, societies or language (among other examples), took place millions of years ago. Are these transitions unique, rare events? Have they instead universal traits that make them almost inevitable when the right pieces are in place? Are there general laws of evolutionary innovation? In order to approach this problem under a novel perspective, we argue that a parallel class of evolutionary transitions can be explored involving the use of artificial evolutionary experiments where alternative paths to innovation can be explored. These 'synthetic' transitions include, for example, the artificial evolution of multicellular systems or the emergence of language in evolved communicating robots. These alternative scenarios could help us to understand the underlying laws that predate the rise of major innovations and the possibility for general laws of evolved complexity. Several key examples and theoretical approaches are summarized and future challenges are outlined.This article is part of the themed issue 'The major synthetic evolutionary transitions'. PMID:27431528

  2. Catalysts from synthetic genetic polymers

    PubMed Central

    Taylor, Alexander I.; Pinheiro, Vitor B.; Smola, Matthew J.; Morgunov, Alexey S.; Peak-Chew, Sew; Cozens, Christopher; Weeks, Kevin M.; Herdewijn, Piet; Holliger, Philipp

    2014-01-01

    The emergence of catalysis in early genetic polymers like RNA is considered a key transition in the origin of life1, predating the appearance of protein enzymes. DNA also demonstrates the capacity to fold into three-dimensional structures and form catalysts in vitro2. However, to what degree these natural biopolymers comprise functionally privileged chemical scaffolds3 for folding or the evolution of catalysis is not known. The ability of synthetic genetic polymers (XNAs) with alternative backbone chemistries not found in nature to fold into defined structures and bind ligands4 raises the possibility that these too might be capable of forming catalysts (XNAzymes). Here we report the discovery of such XNAzymes, elaborated in four different chemistries (ANA (arabino nucleic acids)5, FANA (2′-fluoroarabino nucleic acids)6, HNA (hexitol nucleic acids) and CeNA (cyclohexene nucleic acids)7 directly from random XNA oligomer pools, exhibiting in trans RNA endonuclease and ligase activities. We also describe an XNA-XNA ligase metalloenzyme in the FANA framework, establishing catalysis in an entirely synthetic system and enabling the synthesis of FANA oligomers and an active RNA endonuclease FANAzyme from its constituent parts. These results extend catalysis beyond biopolymers and establish technologies for the discovery of catalysts in a wide range of polymer scaffolds not found in nature8. Evolution of catalysis independent of any natural polymer has implications for the definition of chemical boundary conditions for the emergence of life on earth and elsewhere in the universe9. PMID:25470036

  3. The major synthetic evolutionary transitions.

    PubMed

    Solé, Ricard

    2016-08-19

    Evolution is marked by well-defined events involving profound innovations that are known as 'major evolutionary transitions'. They involve the integration of autonomous elements into a new, higher-level organization whereby the former isolated units interact in novel ways, losing their original autonomy. All major transitions, which include the origin of life, cells, multicellular systems, societies or language (among other examples), took place millions of years ago. Are these transitions unique, rare events? Have they instead universal traits that make them almost inevitable when the right pieces are in place? Are there general laws of evolutionary innovation? In order to approach this problem under a novel perspective, we argue that a parallel class of evolutionary transitions can be explored involving the use of artificial evolutionary experiments where alternative paths to innovation can be explored. These 'synthetic' transitions include, for example, the artificial evolution of multicellular systems or the emergence of language in evolved communicating robots. These alternative scenarios could help us to understand the underlying laws that predate the rise of major innovations and the possibility for general laws of evolved complexity. Several key examples and theoretical approaches are summarized and future challenges are outlined.This article is part of the themed issue 'The major synthetic evolutionary transitions'.

  4. Vectoring of parallel synthetic jets

    NASA Astrophysics Data System (ADS)

    Berk, Tim; Ganapathisubramani, Bharathram; Gomit, Guillaume

    2015-11-01

    A pair of parallel synthetic jets can be vectored by applying a phase difference between the two driving signals. The resulting jet can be merged or bifurcated and either vectored towards the actuator leading in phase or the actuator lagging in phase. In the present study, the influence of phase difference and Strouhal number on the vectoring behaviour is examined experimentally. Phase-locked vorticity fields, measured using Particle Image Velocimetry (PIV), are used to track vortex pairs. The physical mechanisms that explain the diversity in vectoring behaviour are observed based on the vortex trajectories. For a fixed phase difference, the vectoring behaviour is shown to be primarily influenced by pinch-off time of vortex rings generated by the synthetic jets. Beyond a certain formation number, the pinch-off timescale becomes invariant. In this region, the vectoring behaviour is determined by the distance between subsequent vortex rings. We acknowledge the financial support from the European Research Council (ERC grant agreement no. 277472).

  5. Enzymatic biotransformation of synthetic dyes.

    PubMed

    Rodríguez-Couto, S

    2009-11-01

    Environmental pollution by discharge of dye-containing effluents represents a serious ecological concern in many countries. Public demands for colour-free discharges to receiving waters have made decolouration of a variety of industrial wastewater a top priority. The current existing techniques for dye removal have several drawbacks such as high cost, low efficiency, use of large amounts of chemicals and formation of toxic sub-products. This has impelled the search for alternative methods such as those based on oxidative enzymes. This approach is believed to be a promising technology since it is cost-effective, environmentally friendly and does not produce sludge. Enzymatic transformation of synthetic dyes can be described as the conversion of dye molecules by enzymes into simpler and generally colourless molecules. Detailed characterisation of the metabolites produced during enzymatic transformation of synthetic dyes as well as ecotoxicity studies is of great importance to assess the effectiveness of the biodegradation process. However, most reports on the biotreatment of dyes mainly deal with decolouration and there are few reports on the reduction in toxicity or on the identification of the biodegradation products. This implies a limitation to assess their true technical potential.

  6. Synthetic population system user guide

    SciTech Connect

    Roberts, D.J.

    1998-03-01

    The Los Alamos National Laboratory (LANL) TRansportation Analysis SIMulatiuon System (TRANSIMS) synthetic population system (SYN) is designed to produce populations (family households, non-family households, and group quarters) that are statistically equivalent to actual populations when compared at the level of block group or higher. The methodology used by this system is described in a report entitled Creating Synthetic Baseline Populations. The inputs to the system are US Census Bureau data (STF3A and PUMS) and MABLE/GEOCORR data. Census Bureau STF3A and PUMS data formats are commonly used and are available on CD-ROM from the Census Bureau. These data inputs will not be described in any detail in this guide. The primary function of MABLE/GEOCORR data is to cross-reference STF3 block group data to PUMS areas. The outputs of the system are files that contain family household, non-family household, and group quarters data in the form of household and person records. SYN will run on a variety of Unix platforms.

  7. Synthetic vision display evaluation studies

    NASA Technical Reports Server (NTRS)

    Regal, David M.; Whittington, David H.

    1994-01-01

    The goal of this research was to help us understand the display requirements for a synthetic vision system for the High Speed Civil Transport (HSCT). Four experiments were conducted to examine the effects of different levels of perceptual cue complexity in displays used by pilots in a flare and landing task. Increased levels of texture mapping of terrain and runway produced mixed results, including harder but shorter landings and a lower flare initiation altitude. Under higher workload conditions, increased texture resulted in an improvement in performance. An increase in familiar size cues did not result in improved performance. Only a small difference was found between displays using two patterns of high resolution texture mapping. The effects of increased perceptual cue complexity on performance was not as strong as would be predicted from the pilot's subjective reports or from related literature. A description of the role of a synthetic vision system in the High Speed Civil Transport is provide along with a literature review covering applied research related to perceptual cue usage in aircraft displays.

  8. CFIT prevention using synthetic vision

    NASA Astrophysics Data System (ADS)

    Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Kramer, Lynda J.; Bailey, Randall E.; Parrish, Russell V.

    2003-09-01

    In commercial aviation, over 30 percent of all fatal accidents worldwide are categorized as Controlled Flight Into Terrain (CFIT) accidents where a fully functioning airplane is inadvertently flown into the ground, water, or an obstacle. An experiment was conducted at NASA Langley Research Center investigating the presentation of a synthetic terrain database scene to the pilot on a Primary Flight Display (PFD). The major hypothesis for the experiment is that a synthetic vision system (SVS) will improve the pilot's ability to detect and avoid a potential CFIT compared to conventional flight instrumentation. All display conditions, including the baseline, contained a Terrain Awareness and Warning System (TAWS) and Vertical Situation Display (VSD) enhanced Navigation Display (ND). Sixteen pilots each flew 22 approach / departure maneuvers in Instrument Meteorological Conditions (IMC) to the terrain challenged Eagle County Regional Airport (EGE) in Colorado. For the final run, the flight guidance cues were altered such that the departure path went into the terrain. All pilots with a SVS enhanced PFD (12 of 16 pilots) noticed and avoided the potential CFIT situation. All of the pilots who flew the anomaly with the baseline display configuration (which included a TAWS and VSD enhanced ND) had a CFIT event.

  9. CFIT Prevention Using Synthetic Vision

    NASA Technical Reports Server (NTRS)

    Arthur, Jarvis J., III; Prinzel, Lawrence J., III; Kramer, Lynda J.; Bailey, Randall E.; Parrish, Russell V.

    2003-01-01

    In commercial aviation, over 30-percent of all fatal accidents worldwide are categorized as Controlled Flight Into Terrain (CFIT) accidents where a fully functioning airplane is inadvertently flown into the ground, water, or an obstacle. An experiment was conducted at NASA Langley Research Center investigating the presentation of a synthetic terrain database scene to the pilot on a Primary Flight Display (PFD). The major hypothesis for the experiment is that a synthetic vision system (SVS) will improve the pilot s ability to detect and avoid a potential CFIT compared to conventional flight instrumentation. All display conditions, including the baseline, contained a Terrain Awareness and Warning System (TAWS) and Vertical Situation Display (VSD) enhanced Navigation Display (ND). Sixteen pilots each flew 22 approach - departure maneuvers in Instrument Meteorological Conditions (IMC) to the terrain challenged Eagle County Regional Airport (EGE) in Colorado. For the final run, the flight guidance cues were altered such that the departure path went into the terrain. All pilots with a SVS enhanced PFD (12 of 16 pilots) noticed and avoided the potential CFIT situation. All of the pilots who flew the anomaly with the baseline display configuration (which included a TAWS and VSD enhanced ND) had a CFIT event.

  10. Towards developing algal synthetic biology.

    PubMed

    Scaife, Mark Aden; Smith, Alison Gail

    2016-06-15

    The genetic, physiological and metabolic diversity of microalgae has driven fundamental research into photosynthesis, flagella structure and function, and eukaryotic evolution. Within the last 10 years these organisms have also been investigated as potential biotechnology platforms, for example to produce high value compounds such as long chain polyunsaturated fatty acids, pigments and antioxidants, and for biodiesel precursors, in particular triacylglycerols (TAGs). Transformation protocols, molecular tools and genome sequences are available for a number of model species including the green alga Chlamydomonas reinhardtii and the diatom Phaeodactylum tricornutum, although for both species there are bottlenecks to be overcome to allow rapid and predictable genetic manipulation. One approach to do this would be to apply the principles of synthetic biology to microalgae, namely the cycle of Design-Build-Test, which requires more robust, predictable and high throughput methods. In this mini-review we highlight recent progress in the areas of improving transgene expression, genome editing, identification and design of standard genetic elements (parts), and the use of microfluidics to increase throughput. We suggest that combining these approaches will provide the means to establish algal synthetic biology, and that application of standard parts and workflows will avoid parallel development and capitalize on lessons learned from other systems.

  11. Synthetic biology in Streptomyces bacteria.

    PubMed

    Medema, Marnix H; Breitling, Rainer; Takano, Eriko

    2011-01-01

    Actinomycete bacteria of the genus Streptomyces are major producers of bioactive compounds for the biotechnology industry. They are the source of most clinically used antibiotics, as well as of several widely used drugs against common diseases, including cancer . Genome sequencing has revealed that the potential of Streptomyces species for the production of valuable secondary metabolites is even larger than previously realized. Accessing this rich genomic resource to discover new compounds by activating "cryptic" pathways is an interesting challenge for synthetic biology. This approach is facilitated by the inherent natural modularity of secondary metabolite biosynthetic pathways, at the level of individual enzymes (such as modular polyketide synthases), but also of gene cassettes/operons and entire biosynthetic gene clusters. It also benefits from a long tradition of molecular biology in Streptomyces, which provides a number of specific tools, ranging from cloning vectors to inducible promoters and translational control elements. In this chapter, we first provide an overview of the synthetic biology challenges in Streptomyces and then present the existing toolbox of molecular methods that can be employed in this organism. PMID:21601100

  12. Enzymatic biotransformation of synthetic dyes.

    PubMed

    Rodríguez-Couto, S

    2009-11-01

    Environmental pollution by discharge of dye-containing effluents represents a serious ecological concern in many countries. Public demands for colour-free discharges to receiving waters have made decolouration of a variety of industrial wastewater a top priority. The current existing techniques for dye removal have several drawbacks such as high cost, low efficiency, use of large amounts of chemicals and formation of toxic sub-products. This has impelled the search for alternative methods such as those based on oxidative enzymes. This approach is believed to be a promising technology since it is cost-effective, environmentally friendly and does not produce sludge. Enzymatic transformation of synthetic dyes can be described as the conversion of dye molecules by enzymes into simpler and generally colourless molecules. Detailed characterisation of the metabolites produced during enzymatic transformation of synthetic dyes as well as ecotoxicity studies is of great importance to assess the effectiveness of the biodegradation process. However, most reports on the biotreatment of dyes mainly deal with decolouration and there are few reports on the reduction in toxicity or on the identification of the biodegradation products. This implies a limitation to assess their true technical potential. PMID:20214593

  13. Implant rehabilitation in bruxism patient.

    PubMed

    Goiato, Marcelo Coelho; Sonego, Mariana Vilela; dos Santos, Daniela Micheline; da Silva, Emily Vivianne Freitas

    2014-06-06

    A white female patient presented to the university clinic to obtain implant retained prostheses. She had an edentulous maxillary jaw and presented three teeth with poor prognosis (33, 34 and 43). The alveolar bone and the surrounding tissues were healthy. The patient did not report any relevant medical history contraindicating routine dental treatment or implant surgery, but self-reported a dental history of asymptomatic nocturnal bruxism. The treatment plan was set and two Branemark protocols supported by six implants in each arch were installed after a 6-month healing period. A soft occlusal splint was made due to the patient's history of bruxism, and the lack of its use by the patient resulted in an acrylic fracture. The prosthesis was repaired and the importance of using the occlusal splint was restated. In the 4-year follow-up no fractures were reported.

  14. Implant rehabilitation in bruxism patient.

    PubMed

    Goiato, Marcelo Coelho; Sonego, Mariana Vilela; dos Santos, Daniela Micheline; da Silva, Emily Vivianne Freitas

    2014-01-01

    A white female patient presented to the university clinic to obtain implant retained prostheses. She had an edentulous maxillary jaw and presented three teeth with poor prognosis (33, 34 and 43). The alveolar bone and the surrounding tissues were healthy. The patient did not report any relevant medical history contraindicating routine dental treatment or implant surgery, but self-reported a dental history of asymptomatic nocturnal bruxism. The treatment plan was set and two Branemark protocols supported by six implants in each arch were installed after a 6-month healing period. A soft occlusal splint was made due to the patient's history of bruxism, and the lack of its use by the patient resulted in an acrylic fracture. The prosthesis was repaired and the importance of using the occlusal splint was restated. In the 4-year follow-up no fractures were reported. PMID:24907215

  15. Implant rehabilitation in bruxism patient

    PubMed Central

    Goiato, Marcelo Coelho; Sonego, Mariana Vilela; dos Santos, Daniela Micheline; da Silva, Emily Vivianne Freitas

    2014-01-01

    A white female patient presented to the university clinic to obtain implant retained prostheses. She had an edentulous maxillary jaw and presented three teeth with poor prognosis (33, 34 and 43). The alveolar bone and the surrounding tissues were healthy. The patient did not report any relevant medical history contraindicating routine dental treatment or implant surgery, but self-reported a dental history of asymptomatic nocturnal bruxism. The treatment plan was set and two Branemark protocols supported by six implants in each arch were installed after a 6-month healing period. A soft occlusal splint was made due to the patient's history of bruxism, and the lack of its use by the patient resulted in an acrylic fracture. The prosthesis was repaired and the importance of using the occlusal splint was restated. In the 4-year follow-up no fractures were reported. PMID:24907215

  16. [Signal processing in contour implants].

    PubMed

    Ormezzano, Y; Deleurme, C; Vormès, E; Frachet, B

    1990-01-01

    Signal processing by cochlear implants is aimed at transmitting all the acoustic information carried by the human voice, whether in its semantic, esthetic or affective aspects, as an electrical signal. The "translating" approach, which encodes the signal according to the characteristics of the sounds, can only be ideally used in multiple-canal implants. On the contrary, our experience with various single-canal prostheses shows that our patients choose one of these according to the comfort of the signal and to its reliability rather than to the complexity of signal processing: all prostheses produce approximately the same results, whatever the method implemented. The contour implant allows an easy, effective and well-tolerated fitting at low costs.

  17. MRI artefacts after Bonebridge implantation.

    PubMed

    Steinmetz, C; Mader, I; Arndt, S; Aschendorff, A; Laszig, R; Hassepass, F

    2014-07-01

    The new transcutaneous bone conduction implant (BCI) Bonebridge (BB, MED-EL) allows the skin to remain intact and therefore overcomes some issues related to percutaneous systems, such as skin reaction around the external screw and cosmetic complaints. According to manufacturer, BB is MRI conditional up to 1,5 Tesla (T). The artefact of the neurocranium after BB implantation is extensive as shown in the present report. This has to be taken into account when patients suffering conductive, mixed or single-sided hearing loss with candidacy for a BCI are counselled. In patients with comorbid intracranial tumour or other diseases of the brain that require imaging control scans with MRI percutaneous, BCI should be the implant of choice considering the very small artefact of the percutaneous screw in MRI.

  18. Oral Implant Imaging: A Review

    PubMed Central

    GUPTA, Sarika; PATIL, Neelkant; SOLANKI, Jitender; SINGH, Ravinder; LALLER, Sanjeev

    2015-01-01

    Selecting an appropriate implant imaging technique has become a challenging task since the advent of advanced imaging modalities, and many of these are used for implant imaging. On imaging, the modality should not only consider the anatomy but should also provide dimensional accuracy. Many dentists use the conventional method, mostly orthopantograph (OPG), in their routine practice of implant placement. However, because of the drawbacks associated with OPG, higher technologies, such as computed tomography (CT) and cone beam computed tomography (CBCT), are better accepted. These help improve image sharpness and reduce distortion. These techniques are not used widely due to the cost effect. Therefore, to decide on the type of imaging technique, all associated advantages and disadvantages should be considered, which will be broadly discussed in this review. PMID:26715891

  19. Carbon Fiber Biocompatibility for Implants

    PubMed Central

    Petersen, Richard

    2016-01-01

    Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA) to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8) and 0.8 mm at 41.6% vs. 19.5% (p < 10−4), respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration. PMID:26966555

  20. [Needle implantations--clinical report].

    PubMed

    Esswein, W

    1977-04-01

    In the last four years 27 patients with edentulous lower jaw were treated with implantation of rows of tantalum needles; 25 of them were followed up clinically and radiologically. After an average of two years and seven months where the success rate was found to be 72%. Reasons for failure were thought to be mistakes in operative technique, insufficient oral hygiene of the patients and less than optimal aftercare. These needle implants have proved their value also in cases with marked atrophy of the lower jaw where other prosthetic-surgical methods aimed at improving the prosthesis site have failed.

  1. A Percutaneously Implantable Fetal Pacemaker

    PubMed Central

    Zhou, Li; Vest, Adriana N.; Chmait, Ramen H.; Bar-Cohen, Yaniv; Pruetz, Jay; Silka, Michael; Zheng, Kaihui; Peck, Ray; Loeb, Gerald E.

    2015-01-01

    A miniaturized, self-contained pacemaker that could be implanted with a minimally invasive technique would dramatically improve the survival rate for fetuses that develop hydrops fetalis as a result of congenital heart block. We are currently validating a device that we developed to address this bradyarrhythmia. Preclinical studies in a fetal sheep model are underway to demonstrate that the device can be implanted via a minimally invasive approach, can mechanically withstand the harsh bodily environment, can induce effective contractions of the heart muscle with an adequate safety factor, and can successfully operate for the required device lifetime of three months using the previously-developed closed loop transcutaneous recharging system. PMID:25570982

  2. A synthetic zero air standard

    NASA Astrophysics Data System (ADS)

    Pearce, Ruth

    2016-04-01

    A Synthetic Zero Air Standard R. E. Hill-Pearce, K. V. Resner, D. R. Worton, P. J. Brewer The National Physical Laboratory Teddington, Middlesex TW11 0LW UK We present work towards providing traceability for measurements of high impact greenhouse gases identified by the World Meteorological Organisation (WMO) as critical for global monitoring. Standards for these components are required with challengingly low uncertainties to improve the quality assurance and control processes used for the global networks to better assess climate trends. Currently the WMO compatibility goals require reference standards with uncertainties of < 100 nmolmol-1 for CO2 (northern hemisphere) and < 2 nmolmol-1 for CH4 and CO. High purity zero gas is required for both the balance gas in the preparation of reference standards and for baseline calibrations of instrumentation. Quantification of the amount fraction of the target components in the zero gas is a significant contributor to the uncertainty and is challenging due to limited availability of reference standard at the amount fraction of the measurand and limited analytical techniques with sufficient detection limits. A novel dilutor was used to blend NPL Primary Reference Gas Mixtures containing CO2, CH4 and CO at atmospheric amount fractions with a zero gas under test. Several mixtures were generated with nominal dilution ratios ranging from 2000:1 to 350:1. The baseline of two cavity ring down spectrometers was calibrated using the zero gas under test after purification by oxidative removal of CO and hydrocarbons to < 1 nmolmol-1 (SAES PS15-GC50) followed by the removal of CO2 and water vapour to < 100 pmolmol-1 (SAES MC190). Using the standard addition method.[1] we have quantified the amount fraction of CO, CO2, and CH4 in scrubbed whole air (Scott Marrin) and NPL synthetic zero air. This is the first synthetic zero air standard with a matrix of N2, O2 and Ar closely matching ambient composition with gravimetrically assigned

  3. Growth promoting in vitro effect of synthetic cyclic RGD-peptides on human osteoblast-like cells attached to cancellous bone.

    PubMed

    Magdolen, Ursula; Auernheimer, Jörg; Dahmen, Claudia; Schauwecker, Johannes; Gollwitzer, Hans; Tübel, Jutta; Gradinger, Reiner; Kessler, Horst; Schmitt, Manfred; Diehl, Peter

    2006-06-01

    In tissue engineering, the application of biofunctional compounds on biomaterials such as integrin binding RGD-peptides has gained growing interest. Anchorage-dependent cells like osteoblasts bind to these peptides thus ameliorating the integration of a synthetic implant. In case sterilized bone grafts are used as substitutes for reconstruction of bone defects, the ingrowth of the implanted bone is often disturbed because of severe pretreatment such as irradiation or autoclaving, impairing the biological and mechanical properties of the bone. We report for the first time on the in vitro coating of the surface of freshly resected, cleaned bone discs with synthetic, cyclic RGD-peptides. For this approach, two different RGD-peptides were used, one containing two phosphonate anchors, the other peptide four of these binding moieties to allow efficient association of these reactive RGD-peptides to the inorganic bone matrix. Human osteoblast-like cells were cultured on RGD-coated bone discs and the adherence and growth of the cells were analyzed. Coating of bone discs with RGD-peptides did not improve the adhesion rate of osteoblast-like cells to the discs but significantly (up to 40%) accelerated growth of these cells within 8 days after attachment. This effect points to pretreatment of bone implants, especially at the critical interface area between the implanted bone and the non-resected residual bone structure, before re-implantation in order to stimulate and enhance osteointegration of a bone implant. PMID:16685410

  4. FDA Approves Eye Implant for Aging Boomers

    MedlinePlus

    ... fullstory_159648.html FDA Approves Eye Implant for Aging Boomers Tiny lens reshapes cornea to improve focus ... 2016 (HealthDay News) -- An implant that helps the aging eye focus on small print and nearby objects ...

  5. Elderly Benefit from Using Implantable Defibrillators

    MedlinePlus

    ... org Learn More Elderly benefit from using implantable defibrillators June 17, 2013 Categories: Heart News Study Highlights: Older people may benefit from implantable cardioverter defibrillators (ICDs) as much as younger people. Overall health, ...

  6. Beyond cochlear implants: awakening the deafened brain.

    PubMed

    Moore, David R; Shannon, Robert V

    2009-06-01

    Cochlear implants have provided hearing to more than 120,000 deaf people. Recent surgical developments include direct electrical stimulation of the brain, bilateral implants and implantation in children less than 1 year old. However, research is beginning to refocus on the role of the brain in providing benefits to implant users. The auditory system is able to use the highly impoverished input provided by implants to interpret speech, but this only works well in those who have developed language before their deafness or in those who receive their implant at a very young age. We discuss recent evidence suggesting that developing the ability of the brain to learn how to use an implant may be as important as further improvements of the implant technology. PMID:19471266

  7. How Does an Implantable Cardioverter Defibrillator Work?

    MedlinePlus

    ... on Twitter. How Does an Implantable Cardioverter Defibrillator Work? An implantable cardioverter defibrillator (ICD) has wires with ... tune the programming of your ICD so it works better to correct irregular heartbeats. The type of ...

  8. Physiological and molecular determinants of embryo implantation

    PubMed Central

    Zhang, Shuang; Lin, Haiyan; Kong, Shuangbo; Wang, Shumin; Wang, Hongmei; Wang, Haibin; Armant, D. Randall

    2014-01-01

    Embryo implantation involves the intimate interaction between an implantation-competent blastocyst and a receptive uterus, which occurs in a limited time period known as the window of implantation. Emerging evidence shows that defects originating during embryo implantation induce ripple effects with adverse consequences on later gestation events, highlighting the significance of this event for pregnancy success. Although a multitude of cellular events and molecular pathways involved in embryo-uterine crosstalk during implantation have been identified through gene expression studies and genetically engineered mouse models, a comprehensive understanding of the nature of embryo implantation is still missing. This review focuses on recent progress with particular attention to physiological and molecular determinants of blastocyst activation, uterine receptivity, blastocyst attachment and uterine decidualization. A better understanding of underlying mechanisms governing embryo implantation should generate new strategies to rectify implantation failure and improve pregnancy rates in women. PMID:23290997

  9. Word selection affects perceptions of synthetic biology.

    PubMed

    Pearson, Brianna; Snell, Sam; Bye-Nagel, Kyri; Tonidandel, Scott; Heyer, Laurie J; Campbell, A Malcolm

    2011-01-01

    Members of the synthetic biology community have discussed the significance of word selection when describing synthetic biology to the general public. In particular, many leaders proposed the word "create" was laden with negative connotations. We found that word choice and framing does affect public perception of synthetic biology. In a controlled experiment, participants perceived synthetic biology more negatively when "create" was used to describe the field compared to "construct" (p = 0.008). Contrary to popular opinion among synthetic biologists, however, low religiosity individuals were more influenced negatively by the framing manipulation than high religiosity people. Our results suggest that synthetic biologists directly influence public perception of their field through avoidance of the word "create". PMID:21777466

  10. Nature's chemicals and synthetic chemicals: Comparative toxicology

    SciTech Connect

    Ames, B.N.; Profet, M.; Gold, L.S. )

    1990-10-01

    The toxicology of synthetic chemicals is compared to that of natural chemicals, which represent the vast bulk of the chemicals to which humans are exposed. It is argued that animals have a broad array of inducible general defenses to combat the changing array of toxic chemicals in plant food (nature's pesticides) and that these defenses are effective against both natural and synthetic toxins. Synthetic toxins such as dioxin are compared to natural chemicals, such as indole carbinol (in broccoli) and ethanol. Trade-offs between synthetic and natural pesticides are discussed. The finding that in high-dose tests, a high proportion of both natural and synthetic chemicals are carcinogens, mutagens, teratogens, and clastogens (30-50{percent} for each group) undermines current regulatory efforts to protect public health from synthetic chemicals based on these tests.

  11. Synthetic cannabinoids as drugs of abuse.

    PubMed

    Ashton, John C

    2012-06-01

    In the last decade a number of products have appeared in various countries that contain synthetic cannabinoids. This article reviews the history of the sale of these drugs, and the evidence that they contain synthetic cannabinoids. The biochemistry of the synthetic cannabinoids identified thus far is discussed, including a discussion of chemical structures and biochemical targets. The cannabinoid receptor targets for these drugs are discussed, as well as other possible targets such as serotonin receptors. Evidence for the abuse potential of these drugs is reviewed. The toxicity of synthetic cannabinoids and cannabinoid products is reviewed and compared to that of the phytocannabinoid Δ9- tetrahydrocannabinol (THC). As cannabinoids are a structurally diverse class of drugs, it is concluded that synthetic cannabinoids should be classified by biological activity rather than by structure, and that if this isn't done, novel synthetic cannabinoids will continue to emerge that fall outside of current regulatory classification models.

  12. Nature's chemicals and synthetic chemicals: comparative toxicology.

    PubMed Central

    Ames, B N; Profet, M; Gold, L S

    1990-01-01

    The toxicology of synthetic chemicals is compared to that of natural chemicals, which represent the vast bulk of the chemicals to which humans are exposed. It is argued that animals have a broad array of inducible general defenses to combat the changing array of toxic chemicals in plant food (nature's pesticides) and that these defenses are effective against both natural and synthetic toxins. Synthetic toxins such as dioxin are compared to natural chemicals, such as indole carbinol (in broccoli) and ethanol. Trade-offs between synthetic and natural pesticides are discussed. The finding that in high-dose tests, a high proportion of both natural and synthetic chemicals are carcinogens, mutagens, teratogens, and clastogens (30-50% for each group) undermines current regulatory efforts to protect public health from synthetic chemicals based on these tests. PMID:2217211

  13. Implants and Ethnocide: Learning from the Cochlear Implant Controversy

    ERIC Educational Resources Information Center

    Sparrow, Robert

    2010-01-01

    This paper uses the fictional case of the "Babel fish" to explore and illustrate the issues involved in the controversy about the use of cochlear implants in prelinguistically deaf children. Analysis of this controversy suggests that the development of genetic tests for deafness poses a serious threat to the continued flourishing of Deaf culture.…

  14. Mind-controlled transgene expression by a wireless-powered optogenetic designer cell implant

    PubMed Central

    Folcher, Marc; Oesterle, Sabine; Zwicky, Katharina; Thekkottil, Thushara; Heymoz, Julie; Hohmann, Muriel; Christen, Matthias; Daoud El-Baba, Marie; Buchmann, Peter; Fussenegger, Martin

    2014-01-01

    Synthetic devices for traceless remote control of gene expression may provide new treatment opportunities in future gene- and cell-based therapies. Here we report the design of a synthetic mind-controlled gene switch that enables human brain activities and mental states to wirelessly programme the transgene expression in human cells. An electroencephalography (EEG)-based brain–computer interface (BCI) processing mental state-specific brain waves programs an inductively linked wireless-powered optogenetic implant containing designer cells engineered for near-infrared (NIR) light-adjustable expression of the human glycoprotein SEAP (secreted alkaline phosphatase). The synthetic optogenetic signalling pathway interfacing the BCI with target gene expression consists of an engineered NIR light-activated bacterial diguanylate cyclase (DGCL) producing the orthogonal second messenger cyclic diguanosine monophosphate (c-di-GMP), which triggers the stimulator of interferon genes (STING)-dependent induction of synthetic interferon-β promoters. Humans generating different mental states (biofeedback control, concentration, meditation) can differentially control SEAP production of the designer cells in culture and of subcutaneous wireless-powered optogenetic implants in mice. PMID:25386727

  15. Environmental standards for intraocular lens implantation.

    PubMed

    Crawford, B A; Kaufman, D V

    1984-02-01

    Successful implantation of prosthetic devices depends upon their freedom from postoperative inflammation and infection. Techniques and lessons learned in orthopaedic and other implant surgery should be applied to intraocular lens implantation. The avoidance of contamination by particles and micro-organisms is one essential principle of the surgical procedure. Practical steps are described to reduce both types of contamination. These measures taken together are recommended for adoption as a standard of environmental safety for lens implantation.

  16. Detailed spectral analysis of decellularized skin implants

    NASA Astrophysics Data System (ADS)

    Timchenko, E. V.; Timchenko, P. E.; Volova, L. T.; Dolgushkin, D. A.; Shalkovsky, P. Y.; Pershutkina, S. V.

    2016-08-01

    The resutls of detailed analysis of donor skin implants using Raman spectroscopy method are presented. Fourier-deconvolution method was used to separate overlapping spectrum lines and to improve its informativeness. Based on the processed spectra were introduced coefficients that represent changes in relative concentration of implant components, which determines the quality of implants. It was established that Raman spectroscopy method can be used in assessment of skin implants.

  17. Augmentation mammaplasty using implants: a review.

    PubMed

    Takayanagi, Susumu

    2012-09-01

    One of the techniques for augmentation mammaplasty is the procedure using implants. Even though this technique has been used for many years, there are still several controversial issues to be discussed and overcome for patient safety. In this review article, capsular contracture, leak or rupture of the implants, possible systemic disease, relation with breast cancer, and recent problems with Poly Implant Prothese implants are described and discussed. PMID:23094237

  18. Augmentation Mammaplasty Using Implants: A Review

    PubMed Central

    2012-01-01

    One of the techniques for augmentation mammaplasty is the procedure using implants. Even though this technique has been used for many years, there are still several controversial issues to be discussed and overcome for patient safety. In this review article, capsular contracture, leak or rupture of the implants, possible systemic disease, relation with breast cancer, and recent problems with Poly Implant Prothese implants are described and discussed. PMID:23094237

  19. Dental implants in the older adult.

    PubMed

    Jones, John D; Partida, M Norma; Turkyilmaz, Ilser

    2012-01-01

    A need for dental implant treatment in the older population is recognized considering the prevalence of partial and complete edentulism and the positive predictability of implant therapy. Even with a number of barriers to overcome for the older adult seeking implant care, dental implants provide stabilizing support for removable dental appliances and have been shown to be successful in that population. In this paper, we describe quality of life, systemic, surgical, and prosthodontic considerations of this prosthetic treatment along with maintenance challenges.

  20. Synthetic aperture radar target simulator

    NASA Technical Reports Server (NTRS)

    Zebker, H. A.; Held, D. N.; Goldstein, R. M.; Bickler, T. C.

    1984-01-01

    A simulator for simulating the radar return, or echo, from a target seen by a SAR antenna mounted on a platform moving with respect to the target is described. It includes a first-in first-out memory which has digital information clocked in at a rate related to the frequency of a transmitted radar signal and digital information clocked out with a fixed delay defining range between the SAR and the simulated target, and at a rate related to the frequency of the return signal. An RF input signal having a frequency similar to that utilized by a synthetic aperture array radar is mixed with a local oscillator signal to provide a first baseband signal having a frequency considerably lower than that of the RF input signal.

  1. [Mephedrone: a new synthetic drug].

    PubMed

    Petit, Aymeric; Karila, Laurent; Sananes, Michel; Lejoyeux, Michel

    2013-10-01

    Mephedrone is a synthetic psychostimulant derived from cathinone belonging to the family of phenylethylamines. Sold on the Internet, it has recently emerged in France in recreational settings, and is mostly consumed by young people from the gay community and festive environment. Identified in 2008 by the European Monitoring Centre for Drugs and Drug Addiction as a new drug on the market, the use of mephedrone has attracted media attention following the suspicious deaths of two young adults in Sweden and in England. Its legal aspect, ease of getting it on the Internet and cheap price coupled and an alternative-seeking to other psychostimulants make mephedrone a prime target for these populations and a source of abuse, with psychiatric and somatic complications. There is no curative pharmacological treatment approved by health authorities.

  2. Synthetic aperture interferometry: error analysis

    SciTech Connect

    Biswas, Amiya; Coupland, Jeremy

    2010-07-10

    Synthetic aperture interferometry (SAI) is a novel way of testing aspherics and has a potential for in-process measurement of aspherics [Appl. Opt.42, 701 (2003)].APOPAI0003-693510.1364/AO.42.000701 A method to measure steep aspherics using the SAI technique has been previously reported [Appl. Opt.47, 1705 (2008)].APOPAI0003-693510.1364/AO.47.001705 Here we investigate the computation of surface form using the SAI technique in different configurations and discuss the computational errors. A two-pass measurement strategy is proposed to reduce the computational errors, and a detailed investigation is carried out to determine the effect of alignment errors on the measurement process.

  3. Synthetic biology of antimicrobial discovery.

    PubMed

    Zakeri, Bijan; Lu, Timothy K

    2013-07-19

    Antibiotic discovery has a storied history. From the discovery of penicillin by Sir Alexander Fleming to the relentless quest for antibiotics by Selman Waksman, the stories have become like folklore used to inspire future generations of scientists. However, recent discovery pipelines have run dry at a time when multidrug-resistant pathogens are on the rise. Nature has proven to be a valuable reservoir of antimicrobial agents, which are primarily produced by modularized biochemical pathways. Such modularization is well suited to remodeling by an interdisciplinary approach that spans science and engineering. Herein, we discuss the biological engineering of small molecules, peptides, and non-traditional antimicrobials and provide an overview of the growing applicability of synthetic biology to antimicrobials discovery.

  4. Synthetic biology: a utilitarian perspective.

    PubMed

    Smith, Kevin

    2013-10-01

    I examine the positive and negative features of synthetic biology ('SynBio') from a utilitarian ethical perspective. The potential beneficial outcomes from SynBio in the context of medicine are substantial; however it is not presently possible to predict precise outcomes due to the nascent state of the field. Potential negative outcomes from SynBio also exist, including iatrogenesis and bioterrorism; however it is not yet possible to quantify these risks. I argue that the application of a 'precautionary' approach to SynBio is ethically fraught, as is the notion that SynBio-associated knowledge ought to be restricted. I conclude that utilitarians ought to support a broadly laissez-faire stance in respect of SynBio.

  5. Synthetic Jets in Quiescent Air

    NASA Technical Reports Server (NTRS)

    Yao, C. S.; Chen, F. J.; Neuhart, D.; Harris, J.

    2007-01-01

    An oscillatory jet with zero net mass flow is generated by a cavity-pumping actuator. Among the three test cases selected for the Langley CFD validation workshop to assess the current CFD capabilities to predict unsteady flow fields, this basic oscillating jet flow field is the least complex and is selected as the first test case. Increasing in complexity, two more cases studied include jet in cross flow boundary layer and unsteady flow induced by suction and oscillatory blowing with separation control geometries. In this experiment, velocity measurements from three different techniques, hot-wire anemometry, Laser Doppler Velocimetry (LDV) and Particle Image Velocimetry (PIV), documented the synthetic jet flow field. To provide boundary conditions for computations, the experiment also monitored the actuator operating parameters including diaphragm displacement, internal cavity pressure, and internal cavity temperature.

  6. Engineering life through Synthetic Biology.

    PubMed

    Chopra, Paras; Kamma, Akhil

    2006-01-01

    Synthetic Biology is a field involving synthesis of novel biological systems which are not generally found in nature. It has brought a new paradigm in science as it has enabled scientists to create life from the scratch, hence helping better understand the principles of biology. The viability of living organisms that use unnatural molecules is also being explored. Unconventional projects such as DNA playing tic-tac-toe, bacterial photographic film, etc. are taking biology to its extremes. The field holds a promise for mass production of cheap drugs and programming bacteria to seek-and-destroy tumors in the body. However, the complexity of biological systems make the field a challenging one. In addition to this, there are other major technical and ethical challenges which need to be addressed before the field realizes its true potential.

  7. Synthetically Simple, Highly Resilient Hydrogels

    PubMed Central

    Cui, Jun; Lackey, Melissa A.; Madkour, Ahmad E.; Saffer, Erika M.; Griffin, David M.; Bhatia, Surita R.; Crosby, Alfred J.; Tew, Gregory N.

    2014-01-01

    Highly resilient synthetic hydrogels were synthesized by using the efficient thiol-norbornene chemistry to cross-link hydrophilic poly(ethylene glycol) (PEG) and hydrophobic polydimethylsiloxane (PDMS) polymer chains. The swelling and mechanical properties of the hydrogels were well-controlled by the relative amounts of PEG and PDMS. In addition, the mechanical energy storage efficiency (resilience) was more than 97% at strains up to 300%. This is comparable with one of the most resilient materials known: natural resilin, an elastic protein found in many insects, such as in the tendons of fleas and the wings of dragonflies. The high resilience of these hydrogels can be attributed to the well-defined network structure provided by the versatile chemistry, low cross-link density, and lack of secondary structure in the polymer chains. PMID:22372639

  8. Synthetic biology of antimicrobial discovery

    PubMed Central

    Zakeri, Bijan; Lu, Timothy K.

    2012-01-01

    Antibiotic discovery has a storied history. From the discovery of penicillin by Sir Alexander Fleming to the relentless quest for antibiotics by Selman Waksman, the stories have become like folklore, used to inspire future generations of scientists. However, recent discovery pipelines have run dry at a time when multidrug resistant pathogens are on the rise. Nature has proven to be a valuable reservoir of antimicrobial agents, which are primarily produced by modularized biochemical pathways. Such modularization is well suited to remodeling by an interdisciplinary approach that spans science and engineering. Herein, we discuss the biological engineering of small molecules, peptides, and non-traditional antimicrobials and provide an overview of the growing applicability of synthetic biology to antimicrobials discovery. PMID:23654251

  9. Synthetic biology: a utilitarian perspective.

    PubMed

    Smith, Kevin

    2013-10-01

    I examine the positive and negative features of synthetic biology ('SynBio') from a utilitarian ethical perspective. The potential beneficial outcomes from SynBio in the context of medicine are substantial; however it is not presently possible to predict precise outcomes due to the nascent state of the field. Potential negative outcomes from SynBio also exist, including iatrogenesis and bioterrorism; however it is not yet possible to quantify these risks. I argue that the application of a 'precautionary' approach to SynBio is ethically fraught, as is the notion that SynBio-associated knowledge ought to be restricted. I conclude that utilitarians ought to support a broadly laissez-faire stance in respect of SynBio. PMID:24010857

  10. Synthetic chemistry with nitrous oxide.

    PubMed

    Severin, Kay

    2015-10-01

    This review article summarizes efforts to use nitrous oxide (N2O, 'laughing gas') as a reagent in synthetic chemistry. The focus will be on reactions which are carried out in homogeneous solution under (relatively) mild conditions. First, the utilization of N2O as an oxidant is discussed. Due to the low intrinsic reactivity of N2O, selective oxidation reactions of highly reactive compounds are possible. Furthermore, it is shown that transition metal complexes can be used to catalyze oxidation reactions, in some cases with high turnover numbers. In the final part of this overview, the utilization of N2O as a building block for more complex molecules is discussed. It is shown that N2O can be used as an N-atom donor for the synthesis of interesting organic molecules such as triazenes and azo dyes. PMID:26104268

  11. Microorganism Utilization for Synthetic Milk

    NASA Technical Reports Server (NTRS)

    Morford, Megan A.; Khodadad, Christina L.; Caro, Janicce I.; Spencer, LaShelle E.; Richards, Jeffery T.; Strayer, Richard F.; Birmele, Michele N.; Wheeler, Raymond M.

    2014-01-01

    A desired architecture for long duration spaceflight, like aboard the International Space Station or for future missions to Mars, is to provide a supply of fresh food crops for the astronauts. However, some crops can create a high proportion of inedible plant waste. The main goal of the Synthetic Biology project, Cow in a Column, was to produce the components of milk (sugar, lipid, protein) from inedible plant waste by utilizing microorganisms (fungi, yeast, bacteria). Of particular interest was utilizing the valuable polysaccharide, cellulose, found in plant waste, to naturally fuel-through microorganism cellular metabolism- the creation of sugar (glucose), lipid (milk fat), and protein (casein) in order to produce a synthetic edible food product. Environmental conditions such as pH, temperature, carbon source, aeration, and choice microorganisms were optimized in the laboratory and the desired end-products, sugars and lipids, were analyzed. Trichoderma reesei, a known cellulolytic fungus, was utilized to drive the production of glucose, with the intent that the produced glucose would serve as the carbon source for milk fat production and be a substitute for the milk sugar lactose. Lipid production would be carried out by Rhodosporidium toruloides, yeast known to accumulate those lipids that are typically found in milk fat. Results showed that glucose and total lipid content were below what was expected during this phase of experimentation. In addition, individual analysis of six fatty acids revealed that the percentage of each fatty acid was lower than naturally produced bovine milk. Overall, this research indicates that microorganisms could be utilized to breakdown inedible solid waste to produce useable products. For future work, the production of the casein protein for milk would require the development of a genetically modified organism, which was beyond the scope of the original project. Additional trials would be needed to further refine the required

  12. Combined Subpectoral Implantation of Implantable Cardioverter-Defibrillator and Augmentation Mammoplasty in a Young Female Patient

    PubMed Central

    Kim, Dong-Jun; Park, Je Wook; Youn, Jong-Chan; Lee, Dong Won; Koo, Bon-Nyeo; Lee, Moon-Hyoung

    2016-01-01

    Subcutaneous implantation of a cardiac implantable electronic device is the standard method. Occasionally, subpectoral cardiac implantable electronic device (CIED) implantation via axillary incisions is performed in young female patients for cosmetic purposes. Because subpectoral CIED implantation and augmentation mammoplasty involve the same layer, it is feasible to perform both procedures simultaneously. We report a case of combined subpectoral implantation of an implantable cardioverter-defibrillator and augmentation mammoplasty via the axillary approach in a young female patient with dilated cardiomyopathy and small breasts. PMID:27721868

  13. Myths about Cochlear Implants: A Family Perspective.

    ERIC Educational Resources Information Center

    Luetke-Stahlman, B.

    1994-01-01

    A parent of two young children who received cochlear implant surgery addresses common myths about this procedure including "deaf people don't support the use of cochlear implants,""if you choose cochlear implant surgery, you are choosing the hearing world,""hearing parents are not qualified to decide," and "the deaf child him/herself should…

  14. An Uncommon Presentation of Breast Implant Rupture

    PubMed Central

    Watson, David I.; Dean, Nicola R.

    2016-01-01

    Summary: Late periprosthetic seroma has lately been concerning for breast implant-associated anaplastic large cell lymphoma. The authors present an uncommon presentation of breast implant rupture with a seroma and skin rash forming 2 years after insertion of the implant. PMID:27579243

  15. The hydroxyapatite orbital implant: a prospective study.

    PubMed

    Ashworth, J L; Rhatigan, M; Sampath, R; Brammar, R; Sunderland, S; Leatherbarrow, B

    1996-01-01

    The hydroxyapatite orbital implant was first released for use as an orbital implant in humans in August 1989. It has been shown to be well tolerated, providing good motility of the artificial eye with a low complication rate when used as a primary implant. This prospective study evaluated the hydroxyapatite orbital implant used as both a primary and a secondary implant. Sixty patients were implanted between October 1992 and November 1994, 28 being implanted as a primary procedure at the time of enucleation or evisceration, and 32 as a secondary procedure. Seven patients underwent second-stage drilling and pegging of the implant. The mean follow-up time was 13 months (range 2-26 months). A standardised operative and post-operative protocol was followed. The patients were evaluated post-operatively for the amount of enophthalmos, degree of upper lid sulcus deformity, motility of the prosthesis, location of the implant in the socket, socket status and the presence or absence of discharge, position of the drill hole and coverage of the implant. Complications and their management were documented. Both patient and surgeon made a subjective assessment of cosmesis and the patient's satisfaction with the overall result was noted. The results of this study show the hydroxyapatite orbital implant to provide excellent motility of the artificial eye and good cosmesis with a low rate of complications when used both as a primary and as a secondary implant.

  16. Design optimization of functionally graded dental implant.

    PubMed

    Hedia, H S; Mahmoud, Nemat-Alla

    2004-01-01

    The continuous increase of man's life span, and the growing confidence in using artificial materials inside the human body necessities introducing more effective prosthesis and implant materials. However, no artificial implant has biomechanical properties equivalent to the original tissue. Recently, titanium and bioceramic materials, such as hydroxyapatite are extensively used as fabrication materials for dental implant due to their high compatibility with hard tissue and living bone. Titanium has reasonable stiffness and strength while hydroxyapatite has low stiffness, low strength and high ability to reach full integration with living bone. In order to obtain good dental implantation of the biomaterial; full integration of the implant with living bone should be satisfied. Minimum stresses in the implant and the bone must be achieved to increase the life of the implant and prevent bone resorption. Therefore, the aim of the current investigation is to design an implant made from functionally graded material (FGM) to achieve the above advantages. The finite element method and optimization technique are used to reach the required implant design. The optimal materials of the FGM dental implant are found to be hydroxyapatite/titanium. The investigations have shown that the maximum stress in the bone for the hydroxyapatite/titanium FGM implant has been reduced by about 22% and 28% compared to currently used titanium and stainless steel dental implants, respectively.

  17. Using Aerospace Technology To Design Orthopedic Implants

    NASA Technical Reports Server (NTRS)

    Saravanos, D. A.; Mraz, P. J.; Davy, D. T.

    1996-01-01

    Technology originally developed to optimize designs of composite-material aerospace structural components used to develop method for optimizing designs of orthopedic implants. Development effort focused on designing knee implants, long-term goal to develop method for optimizing designs of orthopedic implants in general.

  18. Rescuing failed oral implants via Wnt activation

    PubMed Central

    Yin, Xing; Li, Jingtao; Chen, Tao; Mouraret, Sylvain; Dhamdhere, Girija; Brunski, John B.; Zou, Shujuan; Helms, Jill A.

    2016-01-01

    Aim Implant osseointegration is not always guaranteed and once fibrous encapsulation occurs clinicians have few options other than implant removal. Our goal was to test whether a WNT protein therapeutic could rescue such failed implants. Material and Methods Titanium implants were placed in over-sized murine oral osteotomies. A lack of primary stability was verified by mechanical testing. Interfacial strains were estimated by finite element modelling and histology coupled with histomorphometry confirmed the lack of peri-implant bone. After fibrous encapsulation was established peri-implant injections of a liposomal formulation of WNT3A protein (L-WNT3A) or liposomal PBS (L-PBS) were then initiated. Quantitative assays were employed to analyse the effects of L-WNT3A treatment. Results Implants in gap-type interfaces exhibited high interfacial strains and no primary stability. After verification of implant failure, L-WNT3A or L-PBS injections were initiated. L-WNT3A induced a rapid, significant increase in Wnt responsiveness in the peri-implant environment, cell proliferation and osteogenic protein expression. The amount of peri-implant bone and bone in contact with the implant were significantly higher in L-WNT3A cases. Conclusions These data demonstrate L-WNT3A can induce peri-implant bone formation even in cases where fibrous encapsulation predominates. PMID:26718012

  19. An Uncommon Presentation of Breast Implant Rupture.

    PubMed

    Koh, Eugene; Watson, David I; Dean, Nicola R

    2016-05-01

    Late periprosthetic seroma has lately been concerning for breast implant-associated anaplastic large cell lymphoma. The authors present an uncommon presentation of breast implant rupture with a seroma and skin rash forming 2 years after insertion of the implant. PMID:27579243

  20. Electrospun synthetic human elastin:collagen composite scaffolds for dermal tissue engineering.

    PubMed

    Rnjak-Kovacina, Jelena; Wise, Steven G; Li, Zhe; Maitz, Peter K M; Young, Cara J; Wang, Yiwei; Weiss, Anthony S

    2012-10-01

    We present an electrospun synthetic human elastin:collagen composite scaffold aimed at dermal tissue engineering. The panel of electrospun human tropoelastin and ovine type I collagen blends comprised 80% tropoelastin+20% collagen, 60% tropoelastin+40% collagen and 50% tropoelastin+50% collagen. Electrospinning efficiency decreased with increasing collagen content under the conditions used. Physical and mechanical characterization encompassed fiber morphology, porosity, pore size and modulus, which were prioritized to identify the optimal candidate for dermal tissue regeneration. Scaffolds containing 80% tropoelastin and 20% collagen (80T20C) were selected on this basis for further cell interaction and animal implantation studies. 80T20C enhanced proliferation and migration rates of dermal fibroblasts in vitro and were well tolerated in a mouse subcutaneous implantation study where they persisted over 6 weeks. The 80T20C scaffolds supported fibroblast infiltration, de novo collagen deposition and new capillary formation.

  1. Surface chemistry and effects on bone regeneration of a novel biomimetic synthetic bone filler.

    PubMed

    Morra, Marco; Giavaresi, Gianluca; Sartori, Maria; Ferrari, Andrea; Parrilli, Annapaola; Bollati, Daniele; Baena, Ruggero Rodriguez Y; Cassinelli, Clara; Fini, Milena

    2015-04-01

    The paper presents results of physico-chemical and biological investigations of a surface-engineered synthetic bone filler. Surface analysis confirms that the ceramic phosphate granules present a collagen nanolayer to the surrounding environment. Cell cultures tests show that, in agreement with literature reports, surface-immobilized collagen molecular cues can stimulate progression along the osteogenic pathway of undifferentiated human mesenchymal cells. Finally, in vivo test in a rabbit model of critical bone defects shows statistically significant increase of bone volume and mineral apposition rate between the biomimetic bone filler and collagen-free control. All together, obtained data confirm that biomolecular surface engineering can upgrade the properties of implant device, by promoting more specific and targeted implant-host cells interactions.

  2. Cortical Plasticity after Cochlear Implantation

    PubMed Central

    Petersen, B.; Gjedde, A.; Wallentin, M.; Vuust, P.

    2013-01-01

    The most dramatic progress in the restoration of hearing takes place in the first months after cochlear implantation. To map the brain activity underlying this process, we used positron emission tomography at three time points: within 14 days, three months, and six months after switch-on. Fifteen recently implanted adult implant recipients listened to running speech or speech-like noise in four sequential PET sessions at each milestone. CI listeners with postlingual hearing loss showed differential activation of left superior temporal gyrus during speech and speech-like stimuli, unlike CI listeners with prelingual hearing loss. Furthermore, Broca's area was activated as an effect of time, but only in CI listeners with postlingual hearing loss. The study demonstrates that adaptation to the cochlear implant is highly related to the history of hearing loss. Speech processing in patients whose hearing loss occurred after the acquisition of language involves brain areas associated with speech comprehension, which is not the case for patients whose hearing loss occurred before the acquisition of language. Finally, the findings confirm the key role of Broca's area in restoration of speech perception, but only in individuals in whom Broca's area has been active prior to the loss of hearing. PMID:24377050

  3. Cochlear implant optimized noise reduction.

    PubMed

    Mauger, Stefan J; Arora, Komal; Dawson, Pam W

    2012-12-01

    Noise-reduction methods have provided significant improvements in speech perception for cochlear implant recipients, where only quality improvements have been found in hearing aid recipients. Recent psychoacoustic studies have suggested changes to noise-reduction techniques specifically for cochlear implants, due to differences between hearing aid recipient and cochlear implant recipient hearing. An optimized noise-reduction method was developed with significantly increased temporal smoothing of the signal-to-noise ratio estimate and a more aggressive gain function compared to current noise-reduction methods. This optimized noise-reduction algorithm was tested with 12 cochlear implant recipients over four test sessions. Speech perception was assessed through speech in noise tests with three noise types; speech-weighted noise, 20-talker babble and 4-talker babble. A significant speech perception improvement using optimized noise reduction over standard processing was found in babble noise and speech-weighted noise and over a current noise-reduction method in speech-weighted noise. Speech perception in quiet was not degraded. Listening quality testing for noise annoyance and overall preference found significant improvements over the standard processing and over a current noise-reduction method in speech-weighted and babble noise types. This optimized method has shown significant speech perception and quality improvements compared to the standard processing and a current noise-reduction method.

  4. Advancing Binaural Cochlear Implant Technology.

    PubMed

    Dietz, Mathias; McAlpine, David

    2015-12-30

    This special issue contains a collection of 13 papers highlighting the collaborative research and engineering project entitled Advancing Binaural Cochlear Implant Technology-ABCIT-as well as research spin-offs from the project. In this introductory editorial, a brief history of the project is provided, alongside an overview of the studies.

  5. Advancing Binaural Cochlear Implant Technology

    PubMed Central

    McAlpine, David

    2015-01-01

    This special issue contains a collection of 13 papers highlighting the collaborative research and engineering project entitled Advancing Binaural Cochlear Implant Technology—ABCIT—as well as research spin-offs from the project. In this introductory editorial, a brief history of the project is provided, alongside an overview of the studies. PMID:26721929

  6. [Biomechanics of single dental implants].

    PubMed

    Zagorskiĭ, V A; Zagorskiĭ, V V

    2013-01-01

    Bone tissues of human skull, jawbones and hard dental tissues were formed formed by the influence of chewing loads which are functional irritants used for maintaining their physical qualities. Knowledge of tensions and deformations in bony structures allows to increase their joint work with dental implants installed.

  7. Cortical plasticity after cochlear implantation.

    PubMed

    Petersen, B; Gjedde, A; Wallentin, M; Vuust, P

    2013-01-01

    The most dramatic progress in the restoration of hearing takes place in the first months after cochlear implantation. To map the brain activity underlying this process, we used positron emission tomography at three time points: within 14 days, three months, and six months after switch-on. Fifteen recently implanted adult implant recipients listened to running speech or speech-like noise in four sequential PET sessions at each milestone. CI listeners with postlingual hearing loss showed differential activation of left superior temporal gyrus during speech and speech-like stimuli, unlike CI listeners with prelingual hearing loss. Furthermore, Broca's area was activated as an effect of time, but only in CI listeners with postlingual hearing loss. The study demonstrates that adaptation to the cochlear implant is highly related to the history of hearing loss. Speech processing in patients whose hearing loss occurred after the acquisition of language involves brain areas associated with speech comprehension, which is not the case for patients whose hearing loss occurred before the acquisition of language. Finally, the findings confirm the key role of Broca's area in restoration of speech perception, but only in individuals in whom Broca's area has been active prior to the loss of hearing. PMID:24377050

  8. Contamination Control in Ion Implantation

    SciTech Connect

    Eddy, R.; Doi, D.; Santos, I.; Wriggins, W.

    2011-01-07

    The investigation and elimination or control of metallic contamination in ion implanters has been a leading, continuous effort at implanter OEMs and in fabs/IDMs alike. Much of the efforts have been in the area of control of sputtering through material and geometry changes in apertures, beamline and target chamber components. In this paper, we will focus on an area that has not, heretofore, been fully investigated or controlled. This is the area of lubricants and internal and external support material such as selected cleaning media. Some of these materials are designated for internal use (beamline/vacuum) only while others are for internal and/or external use. Many applications for selected greases, for example, are designated for or are used for platens, implant disks/wheels and for wafer handling components. We will present data from popular lubricants (to be unnamed) used worldwide in ion implanters. This paper will review elements of concern in many lubricants that should be tracked and monitored by all fabs.Proper understanding of the characteristics, risks and the control of these potential contaminants can provide for rapid return to full process capability following major PMs or parts changes. Using VPD-ICPMS, Glow Discharge Mass Spectrometry and Ion Chromatography (IC) data, we will review the typical cleaning results and correlation to ''on wafer'' contamination by elements of concern--and by some elements that are otherwise barred from the fab.

  9. Immediate loading of dental implants.

    PubMed

    Henry, P J; Liddelow, G J

    2008-06-01

    The purpose of this review is to explore the concept of immediate loading as it pertains to dental implants and the indications for clinical practice. The definition of immediate loading will be considered together with a review of the relevant literature in an attempt to provide evidence-based guidelines for successful implementation into practice. A search of electronic databases including Medline, PubMed and the Cochrane Database of Systematic Reviews was undertaken using the terms "immediate loading'', "dental implants'', "immediate function'', "early loading'', "oral implants'', "immediate restoration'' and "systematic review''. This was supplemented by handsearching in peer-reviewed journals and cross-referenced with the articles accessed. Emphasis was given to systematic reviews and controlled clinical trials. A definition of immediate loading was suggested pertinent to the realities of logistics in clinical practice with respect to application and time frame. The literature was evaluated and shown to be limited with significant shortcomings. Guidelines and recommendations for clinical protocols were suggested and illustrated by examples of case types with a minimum of 1-3 years follow-up. A list of additional references for further reading was provided. Within the limitations of this review, there is evidence to suggest that immediate loading protocols have demonstrated high implant survival rates and may be cautiously recommended for certain clinical situations. However, more high level evidence studies, preferably randomized controlled trials (RCTs), over a long time frame are required to show a clear benefit over more conventional loading protocols.

  10. Sterility of packaged implant components.

    PubMed

    Worthington, Philip

    2005-01-01

    Several implant components in their original glass vial and peel-back packages were subjected to sterility testing to determine whether the contents remained sterile after the expiration date marked on the package had passed. The results from a university microbiology laboratory showed that the contents remained sterile for 6 to 11 years after the expiration dates. PMID:15973959

  11. Cortical plasticity after cochlear implantation.

    PubMed

    Petersen, B; Gjedde, A; Wallentin, M; Vuust, P

    2013-01-01

    The most dramatic progress in the restoration of hearing takes place in the first months after cochlear implantation. To map the brain activity underlying this process, we used positron emission tomography at three time points: within 14 days, three months, and six months after switch-on. Fifteen recently implanted adult implant recipients listened to running speech or speech-like noise in four sequential PET sessions at each milestone. CI listeners with postlingual hearing loss showed differential activation of left superior temporal gyrus during speech and speech-like stimuli, unlike CI listeners with prelingual hearing loss. Furthermore, Broca's area was activated as an effect of time, but only in CI listeners with postlingual hearing loss. The study demonstrates that adaptation to the cochlear implant is highly related to the history of hearing loss. Speech processing in patients whose hearing loss occurred after the acquisition of language involves brain areas associated with speech comprehension, which is not the case for patients whose hearing loss occurred before the acquisition of language. Finally, the findings confirm the key role of Broca's area in restoration of speech perception, but only in individuals in whom Broca's area has been active prior to the loss of hearing.

  12. Welded-woven fabrics for use as synthetic, minimally invasive orthopaedic implants

    NASA Astrophysics Data System (ADS)

    Rodts, Timothy W.

    The treatment of osteoarthritis in healthcare today focuses on minimizing pain and retaining mobility. Osteoarthritis of the knee is a common disease and known to be associated with traumatic injuries, among other factors. An identified trend is that patients are younger and have expectations of life with the preservation of an active lifestyle. As a result, great strain is placed on the available offerings of healthcare professionals and device manufacturers alike. This results in numerous design challenges for managing pain and disease over an extended period of time. The available treatments are being extended into younger populations, which increasingly suffer traumatic knee injuries. However, these patients are not good candidates for total joint replacement. A common problem for young patients is localized cartilage damage. This can heal, but often results in a painful condition that requires intervention. A welded-woven three-dimensional polymer fabric was developed to mimic the properties of articular cartilage. A process for the laser welding reinforcement of the surface layers of three-dimensional fabrics was investigated. Confined compression creep and pin-on-disc wear studies were conducted to characterize the contribution of the surface welding reinforcement. All materials used in the studies have previously been used in orthopaedic devices or meet the requirements for United States Pharmacopeial Convention (USP) Class VI biocompatibility approval. The compressive behavior of three-dimensional fabrics was tailored by the inclusion of surface welds. The compressive properties of the welded-woven fabrics were shown to better approximate articular cartilage compressive properties than conventional woven materials. The wear performance was benchmarked against identical fabrics without welding reinforcement. The wear rates were significantly reduced and the lifespan of the fabrics was markedly improved due to surface welding. Welding reinforcement offers a strengthening mechanism as well as a damage-resistant and damage-tolerant treatment for three-dimensional fabrics. Additionally, the concept of reinforcing three-dimensional fabrics in general has been proven and is transferrable to many industries and applications. The manufacturing approaches are scalable and robust.

  13. The development of a composite bone model for training on placement of dental implants

    PubMed Central

    Alkhodary, Mohamed Ahmed; Abdelraheim, Abdelraheim Emad Eldin; Elsantawy, Abd Elaleem Hassan; Al Dahman, Yousef Hamad; Al-Mershed, Mohammed

    2015-01-01

    Objectives It takes a lot of training on patients for both undergraduate to develop clinical sense as regards to the placement of dental implants in the jaw bones, also, the models provided by the dental implant companies for training are usually made of strengthened synthetic foams, which are far from the composition, and tactile sense provided by natural bone during drilling for clinical placement of dental implants. Methodology This is an in-vitro experimental study which utilized bovine femur bone, where the shaft of the femur provided the surface compact layer, and the head provided the cancellous bone layer, to provide a training model similar to jaw bones macroscopic anatomy. Both the compact and cancellous bone samples were characterized using mechanical compressive testing. Results The elastic moduli of the cancellous and cortical femur bone were comparable to those of the human mandible, and the prepared training model provided a more lifelike condition during the drilling and placement of dental implants. Conclusion The composite bone model developed simulated the macroscopic anatomy of the jaw bones having a surface layer of compact bone, and a core of cancellous bone, and provided a better and a more natural hands-on experience for placement of dental implants as compared to plastic models made of polyurethane. PMID:26309434

  14. Biomechanical, Topological and Chemical Features That Influence the Implant Success of an Urogynecological Mesh: A Review

    PubMed Central

    De Maria, Carmelo; Santoro, Vito

    2016-01-01

    Synthetic meshes are normally used to treat several diseases in the field of urogynecological surgery. Not-optimal selection of mesh and/or its not-correct implant may increase patient's pain and discomfort. The knowledge of mechanical behaviour and topological and chemical properties of a mesh plays a fundamental role to minimize patient's suffering and maximize the implant success. We analysed several papers reporting the meshes application for urogynecological pathologies, to extrapolate the principal parameters that normally are used to characterise the biomechanical, topological, and chemical properties, and to verify their influence on implant success. In this way we want demonstrate that, knowing these features, it is possible to foresee the success of a mesh implant. This review shows that the application of a mesh strictly depends on elastic modulus, failure load, porosity and pore size, filament diameter, polymer weight, and crystallinity. To increase the success of the implant and to help choice of optimal mesh for a clinical need, two indexes have been proposed for comparing, in an easier way, the mechanical performance of different commercially available meshes. PMID:27239469

  15. Effectiveness of Implant Therapy Analyzed in a Swedish Population: Prevalence of Peri-implantitis.

    PubMed

    Derks, J; Schaller, D; Håkansson, J; Wennström, J L; Tomasi, C; Berglundh, T

    2016-01-01

    Peri-implantitis is an inflammatory disease affecting soft and hard tissues surrounding dental implants. As the global number of individuals that undergo restorative therapy through dental implants increases, peri-implantitis is considered as a major and growing problem in dentistry. A randomly selected sample of 588 patients who all had received implant-supported therapy 9 y earlier was clinically and radiographically examined. Prevalence of peri-implantitis was assessed and risk indicators were identified by multilevel regression analysis. Forty-five percent of all patients presented with peri-implantitis (bleeding on probing/suppuration and bone loss >0.5 mm). Moderate/severe peri-implantitis (bleeding on probing/suppuration and bone loss >2 mm) was diagnosed in 14.5%. Patients with periodontitis and with ≥4 implants, as well as implants of certain brands and prosthetic therapy delivered by general practitioners, exhibited higher odds ratios for moderate/severe peri-implantitis. Similarly, higher odds ratios were identified for implants installed in the mandible and with crown restoration margins positioned ≤1.5 mm from the crestal bone at baseline. It is suggested that peri-implantitis is a common condition and that several patient- and implant-related factors influence the risk for moderate/severe peri-implantitis (ClinicalTrials.gov NCT01825772). PMID:26701919

  16. Analysis of implant-failure predictors in the posterior maxilla: a retrospective study of 1395 implants.

    PubMed

    Pabst, Andreas Max; Walter, Christian; Ehbauer, Sebastian; Zwiener, Isabella; Ziebart, Thomas; Al-Nawas, Bilal; Klein, Marcus Oliver

    2015-04-01

    The aim of this study was to analyze predictors for dental implant failure in the posterior maxilla. A database was created to include patients being treated with dental implants posterior to the maxillary cuspids. Independent variables thought to be predictive of potential implant failure included (1) sinus elevation, (2) implant length, (3) implant diameter, (4) indication, (5) implant region, (6) timepoint of implant placement, (7) one-vs. two-stage augmentation, and (8) healing mode. Cox regression analysis was used to evaluate the influence of predictors 1-3 on implant failure as dependent variable. The predictors 4-9 were analyzed strictly descriptively. The final database included 592 patients with 1395 implants. The overall 1- and 5-year implant survival rates were 94.8% and 88.6%, respectively. The survival rates for sinus elevation vs. placement into native bone were 94.4% and 95.4%, respectively (p = 0.33). The survival rates for the short (<10 mm), the middle (10-13 mm) and the long implants (>13 mm) were 100%, 89% and 76.8%, respectively (middle-vs. long implants p = 0.62). The implant survival rates for the small- (<3.6 mm), the middle- (3.6-4.5 mm) and the wide diameter implants (>4.5 mm) were 92.5%, 87.9% and 89.6%, respectively (p = 0.0425). None of the parameters evaluated were identified as predictor of implant failure in the posterior maxilla.

  17. IMPORTANCE OF COCHLEAR HEALTH FOR IMPLANT FUNCTION

    PubMed Central

    Pfingst, Bryan E.; Zhou, Ning; Colesa, Deborah J.; Watts, Melissa M.; Strahl, Stefan B.; Garadat, Soha N.; Schvartz-Leyzac, Kara C.; Budenz, Cameron L.; Raphael, Yehoash; Zwolan, Teresa A.

    2014-01-01

    Amazing progress has been made in providing useful hearing to hearing-impaired individuals using cochlear implants, but challenges remain. One such challenge is understanding the effects of partial degeneration of the auditory nerve, the target of cochlear implant stimulation. Here we review studies from our human and animal laboratories aimed at characterizing the health of the implanted cochlea and the auditory nerve. We use the data on cochlear and neural health to guide rehabilitation strategies. The data also motivate the development of tissue-engineering procedures to preserve or build a healthy cochlea and improve performance obtained by cochlear implant recipients or eventually replace the need for a cochlear implant. PMID:25261772

  18. Skeletal implants in aesthetic facial surgery.

    PubMed

    Cox, A J; Wang, T D

    1999-01-01

    The features of the nose, mentum, and malar complex define a person's profile and give the essence of character to the visage. Whether profile deficiencies are due to congenital, traumatic, or aging factors, facial plastic surgeons are able to meet patients' and their own exacting demands more thoroughly with skeletal implants. Although the search for the perfect implant continues, today's armamentarium of implant materials is vast and, with appropriate selection and attention to technique, facial skeletal implants can be successful in creating change impossible to obtain with soft tissue techniques alone. This article reviews both the biomaterials used in mandibular and malar complex implants and the techniques.

  19. Surface biotechnology for refining cochlear implants.

    PubMed

    Tan, Fei; Walshe, Peter; Viani, Laura; Al-Rubeai, Mohamed

    2013-12-01

    The advent of the cochlear implant is phenomenal because it is the first surgical prosthesis that is capable of restoring one of the senses. The subsequent rapid evolution of cochlear implants through increasing complexity and functionality has been synchronized with the recent advancements in biotechnology. Surface biotechnology has refined cochlear implants by directly influencing the implant–tissue interface. Emerging surface biotechnology strategies are exemplified by nanofibrous polymeric materials, topographical surface modification, conducting polymer coatings, and neurotrophin-eluting implants. Although these novel developments have received individual attention in the recent literature, the time has come to investigate their collective applications to cochlear implants to restore lost hearing. PMID:24404581

  20. Choice of a dental implant system.

    PubMed

    Hunt, Peter R; Gartner, Judith L; Norkin, Frederic J

    2005-04-01

    Many dentists are bewildered by the intricacies and complexities of dental implants. They are constantly besieged by product advertisements and can find it difficult to choose which systems to work with. Some dentists are so intimidated by the subject that they choose to avoid getting involved with implants and instead stick to traditional tooth replacement systems. By breaking implants down into 4 main components, the body, collar, connection, and restorative post, it is easier to understand the structure and function of dental implants. Each portion should be designed to achieve certain objectives. Once these structural components are understood, it is easier to compare and contrast differing implant systems.

  1. Surface biotechnology for refining cochlear implants.

    PubMed

    Tan, Fei; Walshe, Peter; Viani, Laura; Al-Rubeai, Mohamed

    2013-12-01

    The advent of the cochlear implant is phenomenal because it is the first surgical prosthesis that is capable of restoring one of the senses. The subsequent rapid evolution of cochlear implants through increasing complexity and functionality has been synchronized with the recent advancements in biotechnology. Surface biotechnology has refined cochlear implants by directly influencing the implant–tissue interface. Emerging surface biotechnology strategies are exemplified by nanofibrous polymeric materials, topographical surface modification, conducting polymer coatings, and neurotrophin-eluting implants. Although these novel developments have received individual attention in the recent literature, the time has come to investigate their collective applications to cochlear implants to restore lost hearing.

  2. Autogenous dermis-fat "baseball" orbital implant.

    PubMed

    Bullock, J D

    1987-01-01

    A new procedure has been devised for the construction of an autogenous dermis-fat orbital implant, in which two figure-eight-shaped dermis-fat grafts are sutured together into a baseball shape. Correct implant size can be determined by preplacement of different-sized Mule spheres and testing for accurate fit. The "baseball" implant eliminates deep orbital fat which is distant from a vascular supply, and because it is covered with dermis, it maximizes graft vascularization, thus promoting survival of the implanted tissues. In eight patients, followed postoperatively for as long as 28 months, baseball implants have produced highly satisfactory results.

  3. Synthetic and biogenic magnetite nanoparticles for tracking of stem cells and dendritic cells

    NASA Astrophysics Data System (ADS)

    Schwarz, Sebastian; Fernandes, Fabiana; Sanroman, Laura; Hodenius, Michael; Lang, Claus; Himmelreich, Uwe; Schmitz-Rode, Thomas; Schueler, Dirk; Hoehn, Mathias; Zenke, Martin; Hieronymus, Thomas

    2009-05-01

    Accurate delivery of cells to target organs is critical for success of cell-based therapies with stem cells or immune cells such as antigen-presenting dendritic cells (DC). Labeling with contrast agents before implantation provides a powerful means for monitoring cellular migration using magnetic resonance imaging (MRI). In this study, we investigated the uptake of fully synthesized or bacterial magnetic nanoparticles (MNPs) into hematopoietic Flt3 + stem cells and DC from mouse bone marrow. We show that (i) uptake of both synthetic and biogenic nanoparticles into cells endow magnetic activity and (ii) low numbers of MNP-loaded cells are readily detected by MRI.

  4. The change of rotational freedom following different insertion torques in three implant systems with implant driver

    PubMed Central

    Kwon, Joo-Hyun; Han, Chong-Hyun; Chang, Jae-Seung

    2009-01-01

    STATEMENT OF PROBLEM Implant drivers are getting popular in clinical dentistry. Unlike to implant systems with external hex connection, implant drivers directly engage the implant/abutment interface. The deformation of the implant/abutment interface can be introduced while placing an implant with its implant driver in clinical situations. PURPOSE This study evaluated the change of rotational freedom between an implant and its abutment after application of different insertion torques. MATERIAL AND METHODS Three kinds of internal connection implants were utilized for the current study (4.5 × 12 mm Xive, 4.3 × 11.5 mm Inplant Magicgrip, 4.3 × 12 mm Implantium MF). An EstheticBase, a 2-piece top, a Dual abutment was used for its corresponding implant system. The rotational freedom between an implant and its abutment were measured before and after applying 45, 100 Ncm insertion torque. Repeated measures ANOVA was used for statistical analysis. RESULTS Under 45 Ncm insertion torque, the rotational freedom between an implant and its abutment was significantly increased in Xive (P = .003). However, no significant change was noted in Inplant Magicgrip and Implantium MF. Under 100 Ncm torque, both in Xive (P = .0005) and Implatium MF (P = .03) resulted in significantly increased rotational freedom between the implant and its abutment. DISCUSSION The design of the implant/implant driver interface effectively prevented the deformation of implant/abutment interface. Little change was noted in the rotational freedom between an implant and its abutment, even though the insertion torque was far beyond clinical application. CONCLUSIONS The implant/abutment joint of internally connecting implants were quite stable under insertion torque in clinical situation. PMID:21165253

  5. Predicting Peri-implant Stresses Around Titanium and Zirconium Dental Implants-A Finite Element Analysis.

    PubMed

    Gujjarlapudi, Manmohan Choudary; Nunna, Narayana Venkata; Manne, Sanjay Dutt; Sarikonda, Varalakshmi Reddy; Madineni, Praveen Kumar; Meruva, Reddi Narasimha Rao

    2013-09-01

    Due to anatomical and surgical constrains the implant placement may not be parallel to each other always. Non-parallel implants are subjected to detrimental stresses at implant bone interface. Also depending on type of implant material i.e. titanium or zirconium, stresses tend to vary due to change in physical and mechanical properties. Hence stress analysis at implant bone interface between different parallel and non-parallel implants becomes significant. Evaluation and comparison of stress distribution in the bone around two parallel and non-parallel titanium and zirconium dental implants on axial and non-axial loading supporting three unit fixed prosthesis. Three dimensional finite element models (M1, M2, M3) were made of three differently angulated implants in ANSYS (11.0 Version) software and P4 processor with a speed of 3 GHz and 3 Gb RAM hardware, common for titanium and zirconium implants. Stress around the implants was analyzed on an axial load of 200 N and a non-axial load of 50 N. In both titanium and zirconium implants on axial loading in cortical bone, higher stresses were observed in M3 followed by M2 and M1. On non-axial loading higher stresses were observed in M2, followed by M3 and M1. In both titanium and zirconium implants on axial and non-axial loading in cancellous bone stresses were higher in M3 followed by M2 and M1. Zirconium implants showed lower stresses in cortical bone and higher stresses in cancellous bone compared to titanium implants. Over all Stresses in the bone were more due to titanium implants than zirconium implants. Zirconium implants led to lower peri-implant stresses than titanium implants.

  6. Opportunities for microfluidic technologies in synthetic biology

    PubMed Central

    Gulati, Shelly; Rouilly, Vincent; Niu, Xize; Chappell, James; Kitney, Richard I.; Edel, Joshua B.; Freemont, Paul S.; deMello, Andrew J.

    2009-01-01

    We introduce microfluidics technologies as a key foundational technology for synthetic biology experimentation. Recent advances in the field of microfluidics are reviewed and the potential of such a technological platform to support the rapid development of synthetic biology solutions is discussed. PMID:19474079

  7. 78 FR 22209 - Additional Synthetic Drug Testing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-15

    ... COMMISSION 10 CFR Part 26 Additional Synthetic Drug Testing AGENCY: Nuclear Regulatory Commission. ACTION... NRC amend its Fitness for Duty program regulations to amend drug testing requirements to test for additional synthetic drugs currently not included in the regulations. The NRC determined that the...

  8. The 'baseball' orbital implant: a prospective study.

    PubMed

    Leatherbarrow, B; Kwartz, J; Sunderland, S; Brammar, R; Nichol, E

    1994-01-01

    The 'baseball' orbital implant was described by Frueh and Felker in 1976. Although this implant was originally described for use as a secondary implant, it has also been widely used as a primary implant at the time of enucleation. This prospective study evaluated the effectiveness of this implant used both primarily and secondarily. Forty-four patients were implanted between April 1990 and May 1991, 19 of the implants being primary and 25 secondary. A standardised operative and post-operative protocol was followed. The mean follow-up time was 31 months (range 24-36 months). The patients were evaluated for the degree of volume replacement, implant and associated prosthesis motility, secondary eyelid and socket problems, patient satisfaction, the need for further surgery and post-operative complications. The overall results achieved by primary implantation were superior to those of secondary implantation. Our results suggest that this implant provides a satisfactory functional and cosmetic rehabilitation of the anophthalmic patient with few complications.

  9. Implant fractures: Rare but not exceptional.

    PubMed

    Sanivarapu, Sahitya; Moogla, Srinivas; Kuntcham, Rupa Sruthi; Kolaparthy, Lakshmi Kanth

    2016-01-01

    Fabrication of dentures aided with implants has become a preferred treatment option for rehabilitation of completely and partially edentulous patients when durability is concerned. Simulation to natural teeth in terms of esthetics and to a greater extent in function can be considered as key elements in the raise of implant dentistry worldwide. Despite its high success rate, therapy with osseointegrated dental implants is not free of complications. Implant failure can occur for other reasons, with implant fracture being one of the major reasons for late failure. Although the incidence of implant fractures may be low, it invariably effects the patient and also clinician. Thus, sound evidence based knowledge of cause of fracture is mandatory for that careful treatment that can reduce the incidence of fracture helping in a better treatment plan. The aim of this review is to enlighten the various causes of implant fracture. PMID:27041830

  10. Implant fractures: Rare but not exceptional

    PubMed Central

    Sanivarapu, Sahitya; Moogla, Srinivas; Kuntcham, Rupa Sruthi; Kolaparthy, Lakshmi Kanth

    2016-01-01

    Fabrication of dentures aided with implants has become a preferred treatment option for rehabilitation of completely and partially edentulous patients when durability is concerned. Simulation to natural teeth in terms of esthetics and to a greater extent in function can be considered as key elements in the raise of implant dentistry worldwide. Despite its high success rate, therapy with osseointegrated dental implants is not free of complications. Implant failure can occur for other reasons, with implant fracture being one of the major reasons for late failure. Although the incidence of implant fractures may be low, it invariably effects the patient and also clinician. Thus, sound evidence based knowledge of cause of fracture is mandatory for that careful treatment that can reduce the incidence of fracture helping in a better treatment plan. The aim of this review is to enlighten the various causes of implant fracture. PMID:27041830

  11. Hydroxyapatite motility implants in ocular prosthetics.

    PubMed

    Cowper, T R

    1995-03-01

    For the past 5 years, an increasing number of ophthalmologists have been using hydroxyapatite (HA) motility implants after uncomplicated enucleation or evisceration of the eye. Unlike previous implant materials, HA promotes fibrovascular ingrowth and seemingly true integration of the motility implant to the residual ocular structures. As a result, a more stable defect and greater movement of the overlying prosthesis is produced. In addition, the problems of long-term orbital implant migration and the vexing postenucleation socket syndrome are thought to be minimized. This article briefly reviews the history and development of orbital implants and HA implant surgical and prosthetic procedures. It is concluded that HA implant rehabilitation is indicated after most uncomplicated enucleations or eviscerations where there is small likelihood of complication.

  12. Synthetic diagnostics platform for fusion plasmas (invited)

    NASA Astrophysics Data System (ADS)

    Shi, L.; Valeo, E. J.; Tobias, B. J.; Kramer, G. J.; Hausammann, L.; Tang, W. M.; Chen, M.

    2016-11-01

    A Synthetic Diagnostics Platform (SDP) for fusion plasmas has been developed which provides state of the art synthetic reflectometry, beam emission spectroscopy, and Electron Cyclotron Emission (ECE) diagnostics. Interfaces to the plasma simulation codes GTC, XGC-1, GTS, and M3D-C1 are provided, enabling detailed validation of these codes. In this paper, we give an overview of SDP's capabilities, and introduce the synthetic diagnostic modules. A recently developed synthetic ECE Imaging module which self-consistently includes refraction, diffraction, emission, and absorption effects is discussed in detail. Its capabilities are demonstrated on two model plasmas. The importance of synthetic diagnostics in validation is shown by applying the SDP to M3D-C1 output and comparing it with measurements from an edge harmonic oscillation mode on DIII-D.

  13. Synthetic therapeutic gene circuits in mammalian cells.

    PubMed

    Ye, Haifeng; Fussenegger, Martin

    2014-08-01

    In the emerging field of synthetic biology, scientists are focusing on designing and creating functional devices, systems, and organisms with novel functions by engineering and assembling standardised biological building blocks. The progress of synthetic biology has significantly advanced the design of functional gene networks that can reprogram metabolic activities in mammalian cells and provide new therapeutic opportunities for future gene- and cell-based therapies. In this review, we describe the most recent advances in synthetic mammalian gene networks designed for biomedical applications, including how these synthetic therapeutic gene circuits can be assembled to control signalling networks and applied to treat metabolic disorders, cancer, and immune diseases. We conclude by discussing the various challenges and future prospects of using synthetic mammalian gene networks for disease therapy.

  14. Mammalian synthetic biology: emerging medical applications

    PubMed Central

    Kis, Zoltán; Pereira, Hugo Sant'Ana; Homma, Takayuki; Pedrigi, Ryan M.; Krams, Rob

    2015-01-01

    In this review, we discuss new emerging medical applications of the rapidly evolving field of mammalian synthetic biology. We start with simple mammalian synthetic biological components and move towards more complex and therapy-oriented gene circuits. A comprehensive list of ON–OFF switches, categorized into transcriptional, post-transcriptional, translational and post-translational, is presented in the first sections. Subsequently, Boolean logic gates, synthetic mammalian oscillators and toggle switches will be described. Several synthetic gene networks are further reviewed in the medical applications section, including cancer therapy gene circuits, immuno-regulatory networks, among others. The final sections focus on the applicability of synthetic gene networks to drug discovery, drug delivery, receptor-activating gene circuits and mammalian biomanufacturing processes. PMID:25808341

  15. Development of synthetic lethality anticancer therapeutics.

    PubMed

    Fang, Bingliang

    2014-10-01

    The concept of synthetic lethality (the creation of a lethal phenotype from the combined effects of mutations in two or more genes) has recently been exploited in various efforts to develop new genotype-selective anticancer therapeutics. These efforts include screening for novel anticancer agents, identifying novel therapeutic targets, characterizing mechanisms of resistance to targeted therapy, and improving efficacies through the rational design of combination therapy. This review discusses recent developments in synthetic lethality anticancer therapeutics, including poly ADP-ribose polymerase inhibitors for BRCA1- and BRCA2-mutant cancers, checkpoint inhibitors for p53 mutant cancers, and small molecule agents targeting RAS gene mutant cancers. Because cancers are caused by mutations in multiple genes and abnormalities in multiple signaling pathways, synthetic lethality for a specific tumor suppressor gene or oncogene is likely cell context-dependent. Delineation of the mechanisms underlying synthetic lethality and identification of treatment response biomarkers will be critical for the success of synthetic lethality anticancer therapy.

  16. Mammalian synthetic biology: emerging medical applications.

    PubMed

    Kis, Zoltán; Pereira, Hugo Sant'Ana; Homma, Takayuki; Pedrigi, Ryan M; Krams, Rob

    2015-05-01

    In this review, we discuss new emerging medical applications of the rapidly evolving field of mammalian synthetic biology. We start with simple mammalian synthetic biological components and move towards more complex and therapy-oriented gene circuits. A comprehensive list of ON-OFF switches, categorized into transcriptional, post-transcriptional, translational and post-translational, is presented in the first sections. Subsequently, Boolean logic gates, synthetic mammalian oscillators and toggle switches will be described. Several synthetic gene networks are further reviewed in the medical applications section, including cancer therapy gene circuits, immuno-regulatory networks, among others. The final sections focus on the applicability of synthetic gene networks to drug discovery, drug delivery, receptor-activating gene circuits and mammalian biomanufacturing processes.

  17. Synthetic biology: an emerging engineering discipline.

    PubMed

    Cheng, Allen A; Lu, Timothy K

    2012-01-01

    Over the past decade, synthetic biology has emerged as an engineering discipline for biological systems. Compared with other substrates, biology poses a unique set of engineering challenges resulting from an incomplete understanding of natural biological systems and tools for manipulating them. To address these challenges, synthetic biology is advancing from developing proof-of-concept designs to focusing on core platforms for rational and high-throughput biological engineering. These platforms span the entire biological design cycle, including DNA construction, parts libraries, computational design tools, and interfaces for manipulating and probing synthetic circuits. The development of these enabling technologies requires an engineering mindset to be applied to biology, with an emphasis on generalizable techniques in addition to application-specific designs. This review aims to discuss the progress and challenges in synthetic biology and to illustrate areas where synthetic biology may impact biomedical engineering and human health.

  18. Synthetic mammalian gene circuits for biomedical applications.

    PubMed

    Ye, Haifeng; Aubel, Dominique; Fussenegger, Martin

    2013-12-01

    Synthetic biology is the science of reassembling cataloged and standardized biological items in a systematic and rational manner to create and engineer functional biological designer devices, systems and organisms with novel and useful, preferably therapeutic functions. Synthetic biology has significantly advanced the design of complex genetic networks that can reprogram metabolic activities in mammalian cells and provide novel therapeutic strategies for future gene-based and cell-based therapies. Synthetic biology-inspired therapeutic strategies provide new opportunities for improving human health in the 21st century. This review covers the most recent synthetic mammalian circuits designed for therapy of diseases such as metabolic disorders, cancer, and immune disorders. We conclude by discussing current challenges and future perspectives for biomedical applications of synthetic mammalian gene networks.

  19. Implantation of nitrogen: Effects of hydrogen and implantation energy

    NASA Technical Reports Server (NTRS)

    Sugiura, Naoji; Futagami, Tsuneji; Nagai, Siro

    1993-01-01

    To solve the question on solar nitrogen in lunar soils, i.e. variation in isotopic composition and apparently high retentivity compared with rare gases, nitrogen implantation experiments were conducted. At the Meteoritical Society Meeting in Copenhagen, the results of stepped combustion of implanted nitrogen in ilmenite and olivine were presented. The degassing behavior of nitrogen (and also Ar) was quite different from that observed in the case of lunar soils. Extraction temperatures are higher (greater than 1100 C for ilmenite and 1500 C for olivine) than that for lunar soils. Both nitrogen and Ar seem to be retained at the same efficiency. Therefore, additional experiments were conducted to make degassing behavior of nitrogen more close to that observed in the case of lunar soils.

  20. [Evaluation of asymetric implants in breast cancer].

    PubMed

    Fitoussi, A; Couturaud, B; Laki, F; Alran, S; Salmon, R J

    2005-10-01

    Since more than twenty years, methods of breast reconstruction using implants have continued to evolve in order to improve their aesthetic results. Shapes and materials of these implants have also evolved to obtain contours similar to that of the natural opposite breast. Therefore it can be considered that the use of asymmetric implants is the last step in implant technology before using made to measure implants. Asymmetric implants allow obtaining different contours in harmony to the different breast shapes according to the side, left or right, of the reconstructed breast which maximise the naturalness of the result. Such implants have an axis directed towards the exterior and lower part of the chest wall, are wider than high with a thinner part on their inner edge and a concave rear side moulding the curves of the chest wall. In our own experience, we placed more than 500 asymmetric implants. When analysing retrospectively the medical records of 156 patients, no distinctive features were observed when compared to symmetric classic implants in easiness in the surgical procedure or in complications except a slightly higher rate of seroma formation. When compared to usual implants the main benefits of asymmetric implants are: to offer a wider breadth, to slope down gently on their upper and inner sides according to their concave rear side, and therefore to better match subtle curves of a normal breast. Moreover such contours allow a distribution of the volume which fit better to the usual natural breast configuration of patients who underwent surgery for breast carcinoma. At last, such implants are easy to place and a very low rate of secondary rotation has been observed. In summary, for all these reasons, asymmetric implants, can be considered to be the class one in the choice of implants for breast reconstruction after breast surgery. PMID:16198040

  1. Synthetic Landau levels for photons.

    PubMed

    Schine, Nathan; Ryou, Albert; Gromov, Andrey; Sommer, Ariel; Simon, Jonathan

    2016-06-30

    Synthetic photonic materials are an emerging platform for exploring the interface between microscopic quantum dynamics and macroscopic material properties. Photons experiencing a Lorentz force develop handedness, providing opportunities to study quantum Hall physics and topological quantum science. Here we present an experimental realization of a magnetic field for continuum photons. We trap optical photons in a multimode ring resonator to make a two-dimensional gas of massive bosons, and then employ a non-planar geometry to induce an image rotation on each round-trip. This results in photonic Coriolis/Lorentz and centrifugal forces and so realizes the Fock–Darwin Hamiltonian for photons in a magnetic field and harmonic trap. Using spatial- and energy-resolved spectroscopy, we track the resulting photonic eigenstates as radial trapping is reduced, finally observing a photonic Landau level at degeneracy. To circumvent the challenge of trap instability at the centrifugal limit, we constrain the photons to move on a cone. Spectroscopic probes demonstrate flat space (zero curvature) away from the cone tip. At the cone tip, we observe that spatial curvature increases the local density of states, and we measure fractional state number excess consistent with the Wen–Zee theory, providing an experimental test of this theory of electrons in both a magnetic field and curved space. This work opens the door to exploration of the interplay of geometry and topology, and in conjunction with Rydberg electromagnetically induced transparency, enables studies of photonic fractional quantum Hall fluids and direct detection of anyons.

  2. Nanostructures from Synthetic Genetic Polymers

    PubMed Central

    Beuron, Fabienne; Peak‐Chew, Sew‐Yeu; Morris, Edward P.; Herdewijn, Piet

    2016-01-01

    Abstract Nanoscale objects of increasing complexity can be constructed from DNA or RNA. However, the scope of potential applications could be enhanced by expanding beyond the moderate chemical diversity of natural nucleic acids. Here, we explore the construction of nano‐objects made entirely from alternative building blocks: synthetic genetic polymers not found in nature, also called xeno nucleic acids (XNAs). Specifically, we describe assembly of 70 kDa tetrahedra elaborated in four different XNA chemistries (2′‐fluro‐2′‐deoxy‐ribofuranose nucleic acid (2′F‐RNA), 2′‐fluoroarabino nucleic acids (FANA), hexitol nucleic acids (HNA), and cyclohexene nucleic acids (CeNA)), as well as mixed designs, and a ∼600 kDa all‐FANA octahedron, visualised by electron microscopy. Our results extend the chemical scope for programmable nanostructure assembly, with implications for the design of nano‐objects and materials with an expanded range of structural and physicochemical properties, including enhanced biostability. PMID:26992063

  3. Synthetic Landau levels for photons

    NASA Astrophysics Data System (ADS)

    Schine, Nathan; Ryou, Albert; Gromov, Andrey; Sommer, Ariel; Simon, Jonathan

    2016-06-01

    Synthetic photonic materials are an emerging platform for exploring the interface between microscopic quantum dynamics and macroscopic material properties. Photons experiencing a Lorentz force develop handedness, providing opportunities to study quantum Hall physics and topological quantum science. Here we present an experimental realization of a magnetic field for continuum photons. We trap optical photons in a multimode ring resonator to make a two-dimensional gas of massive bosons, and then employ a non-planar geometry to induce an image rotation on each round-trip. This results in photonic Coriolis/Lorentz and centrifugal forces and so realizes the Fock–Darwin Hamiltonian for photons in a magnetic field and harmonic trap. Using spatial- and energy-resolved spectroscopy, we track the resulting photonic eigenstates as radial trapping is reduced, finally observing a photonic Landau level at degeneracy. To circumvent the challenge of trap instability at the centrifugal limit, we constrain the photons to move on a cone. Spectroscopic probes demonstrate flat space (zero curvature) away from the cone tip. At the cone tip, we observe that spatial curvature increases the local density of states, and we measure fractional state number excess consistent with the Wen–Zee theory, providing an experimental test of this theory of electrons in both a magnetic field and curved space. This work opens the door to exploration of the interplay of geometry and topology, and in conjunction with Rydberg electromagnetically induced transparency, enables studies of photonic fractional quantum Hall fluids and direct detection of anyons.

  4. Electrospun Synthetic Polypeptide Nanofibrous Biomaterials

    NASA Astrophysics Data System (ADS)

    Khadka, Dhan; Haynie, Donald

    2011-03-01

    Water-insoluble nanofiber mats of synthetic polypeptides of defined composition have been prepared from fibers electrospun from aqueous solution in the absence of organic co-solvents. 20-50 kDa poly(L-glutamate, L-tyrosine) 4:1 (PLGY) but not 15-50 kDa or 50-100 kDa poly(L-glutamate) was spinnable at 20-55% (w/v) polymer in water. Applied voltage and needle-collector distance were crucial for spinnability. Attractive fibers were obtained at 50% polymer. Fiber diameter and mat morphology have been characterized by electron microscopy. Exposure of spun fiber mats to 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), which reacts with carboxylate, decreased fiber solubility. Fluorescein-conjugated poly(L-lysine) (FITC-PLL) but not the fluorophore alone was able bind PLGY fiber mats electrostatically, judging by fluorescence microscopy. Key advances of this work are the avoidance of an animal source of peptides and of an inorganic co-solvent to achieve polypeptide spinnability. Polypeptide fiber mats are a promising type of nano-structured biomaterial for applications in biomedicine and biotechnology.

  5. Disease, dysfunction, and synthetic biology.

    PubMed

    Holm, Sune

    2014-08-01

    Theorists analyzing the concept of disease on the basis of the notion of dysfunction consider disease to be dysfunction requiring. More specifically, dysfunction-requiring theories of disease claim that for an individual to be diseased certain biological facts about it must be the case. Disease is not wholly a matter of evaluative attitudes. In this paper, I consider the dysfunction-requiring component of Wakefield's hybrid account of disease in light of the artifactual organisms envisioned by current research in synthetic biology. In particular, I argue that the possibility of artifactual organisms and the case of oncomice and other bred or genetically modified strains of organism constitute a significant objection to Wakefield's etiological account of the dysfunction requirement. I then develop a new alternative understanding of the dysfunction requirement that builds on the organizational theory of function. I conclude that my suggestion is superior to Wakefield's theory because it (a) can accommodate both artifactual and naturally evolved organisms, (b) avoids the possibility of there being a conflict between what an organismic part is supposed to do and the health of the organism, and (c) provides a nonarbitrary and practical way of determining whether dysfunction occurs.

  6. Synthetic polymers for solar harvesting.

    PubMed

    Ghiggino, Kenneth P; Bell, Toby D M; Hooley, Emma N

    2012-01-01

    Synthetic polymers incorporating appropriate chromophores can act as light harvesting antennae for artificial photosynthetic systems. The photophysical processes occurring in a polymer based on phenylene vinylene have been investigated at the single chain level and in bulk solution to study energy transfer processes. Most single chains of an alternating copolymer of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene and 1,4-phenylene vinylene (alt-co-MEH-PPV) dispersed in a transparent polymer matrix act as single chromophore emitters demonstrating that energy transfer is an efficient process in these polymers. However for individual polymer chains there are fluctuations in emission intensity ('blinking') and shifts in emission spectra, decay lifetimes and emission dipole orientation occurring on a time-scale of tens of seconds. Fluorescence blinking also occurs on a sub-millisecond time-scale and follows exponential kinetics, whereas the longer blinking is better described by a power law. These observations can be interpreted as arising from environmental relaxation processes and/or changes in the emitter and demonstrate the wide distribution of photophysical behaviours that can be observed among the individual molecules of a polymer sample. The relevance of these studies to the application of polymer materials for solar harvesting is highlighted.

  7. Synthetic Landau levels for photons

    NASA Astrophysics Data System (ADS)

    Schine, Nathan; Ryou, Albert; Gromov, Andrey; Sommer, Ariel; Simon, Jonathan

    2016-06-01

    Synthetic photonic materials are an emerging platform for exploring the interface between microscopic quantum dynamics and macroscopic material properties. Photons experiencing a Lorentz force develop handedness, providing opportunities to study quantum Hall physics and topological quantum science. Here we present an experimental realization of a magnetic field for continuum photons. We trap optical photons in a multimode ring resonator to make a two-dimensional gas of massive bosons, and then employ a non-planar geometry to induce an image rotation on each round-trip. This results in photonic Coriolis/Lorentz and centrifugal forces and so realizes the Fock-Darwin Hamiltonian for photons in a magnetic field and harmonic trap. Using spatial- and energy-resolved spectroscopy, we track the resulting photonic eigenstates as radial trapping is reduced, finally observing a photonic Landau level at degeneracy. To circumvent the challenge of trap instability at the centrifugal limit, we constrain the photons to move on a cone. Spectroscopic probes demonstrate flat space (zero curvature) away from the cone tip. At the cone tip, we observe that spatial curvature increases the local density of states, and we measure fractional state number excess consistent with the Wen-Zee theory, providing an experimental test of this theory of electrons in both a magnetic field and curved space. This work opens the door to exploration of the interplay of geometry and topology, and in conjunction with Rydberg electromagnetically induced transparency, enables studies of photonic fractional quantum Hall fluids and direct detection of anyons.

  8. The major synthetic evolutionary transitions

    PubMed Central

    Solé, Ricard

    2016-01-01

    Evolution is marked by well-defined events involving profound innovations that are known as ‘major evolutionary transitions'. They involve the integration of autonomous elements into a new, higher-level organization whereby the former isolated units interact in novel ways, losing their original autonomy. All major transitions, which include the origin of life, cells, multicellular systems, societies or language (among other examples), took place millions of years ago. Are these transitions unique, rare events? Have they instead universal traits that make them almost inevitable when the right pieces are in place? Are there general laws of evolutionary innovation? In order to approach this problem under a novel perspective, we argue that a parallel class of evolutionary transitions can be explored involving the use of artificial evolutionary experiments where alternative paths to innovation can be explored. These ‘synthetic’ transitions include, for example, the artificial evolution of multicellular systems or the emergence of language in evolved communicating robots. These alternative scenarios could help us to understand the underlying laws that predate the rise of major innovations and the possibility for general laws of evolved complexity. Several key examples and theoretical approaches are summarized and future challenges are outlined. This article is part of the themed issue ‘The major synthetic evolutionary transitions’. PMID:27431528

  9. Synthetic Landau levels for photons.

    PubMed

    Schine, Nathan; Ryou, Albert; Gromov, Andrey; Sommer, Ariel; Simon, Jonathan

    2016-06-30

    Synthetic photonic materials are an emerging platform for exploring the interface between microscopic quantum dynamics and macroscopic material properties. Photons experiencing a Lorentz force develop handedness, providing opportunities to study quantum Hall physics and topological quantum science. Here we present an experimental realization of a magnetic field for continuum photons. We trap optical photons in a multimode ring resonator to make a two-dimensional gas of massive bosons, and then employ a non-planar geometry to induce an image rotation on each round-trip. This results in photonic Coriolis/Lorentz and centrifugal forces and so realizes the Fock–Darwin Hamiltonian for photons in a magnetic field and harmonic trap. Using spatial- and energy-resolved spectroscopy, we track the resulting photonic eigenstates as radial trapping is reduced, finally observing a photonic Landau level at degeneracy. To circumvent the challenge of trap instability at the centrifugal limit, we constrain the photons to move on a cone. Spectroscopic probes demonstrate flat space (zero curvature) away from the cone tip. At the cone tip, we observe that spatial curvature increases the local density of states, and we measure fractional state number excess consistent with the Wen–Zee theory, providing an experimental test of this theory of electrons in both a magnetic field and curved space. This work opens the door to exploration of the interplay of geometry and topology, and in conjunction with Rydberg electromagnetically induced transparency, enables studies of photonic fractional quantum Hall fluids and direct detection of anyons. PMID:27281214

  10. Mini vs. Standard Implants for Mandibular Overdentures: A Randomized Trial.

    PubMed

    de Souza, R F; Ribeiro, A B; Della Vecchia, M P; Costa, L; Cunha, T R; Reis, A C; Albuquerque, R F

    2015-10-01

    A mandibular implant-retained overdenture is considered a first-choice treatment for edentulism. However, some aspects limit the use of standard implants-for example, the width of edentulous ridges, chronic diseases, fear, or costs. This randomized trial compared mandibular overdentures retained by 2 or 4 mini-implants with standard implants, considering oral health-related quality of life (OHRQoL), patient satisfaction, and complications such as lost implant. In sum, 120 edentulous men and women (mean age, 59.5 ± 8.5 y) randomly received 4 mini-implants, 2 mini-implants, or 2 standard implants. Participants provided data regarding OHRQoL and satisfaction until 12 mo. Clinical parameters, including implant survival rate, were also recorded. Both 2 and 4 mini-implants led to better OHRQoL, compared with 2 standard implants. Treatment with 4 mini-implants was more satisfying than 2 standard implants, with 2 mini-implants presenting intermediate results. Implant survival rate was 89%, 82%, and 99% for 4 mini-implants, 2 mini-implants, or 2 standard implants, respectively. Overdentures retained by 4 or 2 mini-implants can achieve OHRQoL and satisfaction at least comparable with that of 2 standard implants. However, the survival rate of mini implants is not as high as that of standard implants (ClinicalTrials.gov NCT01411683).

  11. Hydroxyapatite ocular implant and non-integrated implants in eviscerated patients

    PubMed Central

    Gradinaru, S; Popescu, V; Leasu, C; Pricopie, S; Yasin, S; Ciuluvica, R; Ungureanu, E

    2015-01-01

    Introduction: This study compares the outcomes and complications of hydroxyapatite ocular implant and non-integrated ocular implants following evisceration. Materials and Methods: This is a retrospective study of 90 patients who underwent evisceration for different ocular affections, in the Ophthalmology Department of the University Emergency Hospital Bucharest, between January 2009 and December 2013. The outcomes measured were conjunctival dehiscence, socket infection, implant exposure and extrusion rate. Results: Forty-three patients had the hydroxyapatite implant (coralline–Integrated Ocular Implants, USA or synthetic–FCI, France) and forty-seven received non-integrated ocular implants (24 acrylic and 23 silicone). Five cases of socket infection, thirteen cases of extrusion and two cases of conjunctival dehiscence were encountered. Conclusions: There was a higher rate of conjunctival dehiscence with hydroxyapatite ocular implant, but implant extrusion and socket infection were found in non-integrated ocular implants. PMID:25914747

  12. Decontamination of dental implant surface in peri-implantitis treatment: A literature review

    PubMed Central

    Buitrago-Vera, Pedro; Solá-Ruiz, María F.; Ferrer-García, Juan C.

    2013-01-01

    Etiological treatment of peri-implantitis aims to reduce the bacterial load within the peri-implant pocket and decontaminate the implant surface in order to promote osseointegration. The aim of this literature review was to evaluate the efficacy of different methods of implant surface decontamination. A search was conducted using the PubMed (Medline) database, which identified 36 articles including in vivo and in vitro studies, and reviews of different decontamination systems (chemical, mechanical, laser and photodynamic therapies). There is sufficient consensus that, for the treatment of peri-implant infections, the mechanical removal of biofilm from the implant surface should be supplemented by chemical decontamination with surgical access. However, more long-term research is needed to confirm this and to establish treatment protocols responding to different implant characterics. Key words:Peri-implantitis, treatment, decontamination, implant surface, laser. PMID:23986023

  13. Effect of Platelet-Rich-Plasma (PRP) and Implant Surface Topography on Implant Stability and Bone

    PubMed Central

    Kundu, Renu

    2014-01-01

    Purpose: To evaluate the effect of Platelet-Rich-Plasma (PRP) and different implant surface topography on implant stability and bone levels around immediately loaded dental implants. Materials and Methods: Dental implants were placed in subjects divided into two groups and four subgroups on basis of implant treatment with PRP and implant surface topography used. A total of 30 implants were placed, 15 in each group. For PRP group, implants were placed after surface treatment with PRP. Temporization was done within two weeks and final prosthesis was given after three months. Implant stability was measured with Periotest at baseline, one month and three months. Bone height was measured on mesial & distal side on standardized IOPA x-rays. Results: A statistically significant difference was noticed in implant stability with PRP at baseline. The effect of PRP on bone height changes was not statistically significant. A synergistic effect of PRP and square thread-form was observed on improved implant stability and bone levels; however, no such effect is seen with PRP and reverse buttress thread-form. Conclusion: Within the limitation of this study, enhancement on implant stability and bone healing was observed with PRP treated implant surfaces, and with use of implant with square thread-form. PMID:25121060

  14. Does the number of implants have any relation with peri-implant disease?

    PubMed Central

    PASSONI, Bernardo Born; DALAGO, Haline Renata; SCHULDT FILHO, Guenther; OLIVEIRA DE SOUZA, João Gustavo; BENFATTI, César Augusto Magalhães; MAGINI, Ricardo de Souza; BIANCHINI, Marco Aurélio

    2014-01-01

    Objective The aim of this study was to evaluate the relationship between the number of pillar implants of implant-supported fixed prostheses and the prevalence of periimplant disease. Material and Methods Clinical and radiographic data were obtained for the evaluation. The sample consisted of 32 patients with implant-supported fixed prostheses in function for at least one year. A total of 161 implants were evaluated. Two groups were formed according to the number of implants: G1) ≤5 implants and G2) >5 implants. Data collection included modified plaque index (MPi), bleeding on probing (BOP), probing depth (PD), width of keratinized mucosa (KM) and radiographic bone loss (BL). Clinical and radiographic data were grouped for each implant in order to conduct the diagnosis of mucositis or peri-implantitis. Results Clinical parameters were compared between groups using Student's t test for numeric variables (KM, PD and BL) and Mann-Whitney test for categorical variables (MPi and BOP). KM and BL showed statistically significant differences between both groups (p<0.001). Implants from G1 – 19 (20.43%) – compared with G2 – 26 (38.24%) – showed statistically significant differences regarding the prevalence of peri-implantitis (p=0.0210). Conclusion It seems that more than 5 implants in total fixed rehabilitations increase bone loss and consequently the prevalence of implants with periimplantitis. Notwithstanding, the number of implants does not have any influence on the prevalence of mucositis. PMID:25466474

  15. Dental implants with versus without peri-implant bone defects treated with guided bone regeneration

    PubMed Central

    Peñarrocha-Oltra, David; Peñarrocha-Diago, Maria; Peñarrocha-Diago, Miguel

    2015-01-01

    Background The guided bone regeneration (GBR) technique is highly successful for the treatment of peri-implant bone defects. The aim was to determine whether or not implants associated with GBR due to peri-implant defects show the same survival and success rates as implants placed in native bone without defects. Material and Methods Patients with a minimum of two submerged dental implants: one suffering a dehiscence or fenestration defect during placement and undergoing simultaneous guided bone regeneration (test group), versus the other entirely surrounded by bone (control group) were treated and monitored annually for three years. Complications with the healing procedure, implant survival, implant success and peri-implant marginal bone loss were assessed. Statistical analysis was performed with non-parametric tests setting an alpha value of 0.05. Results Seventy-two patients and 326 implants were included (142 test, 184 control). One hundred and twenty-five dehiscences (average height 1.92±1.11) and 18 fenestrations (average height 3.34±2.16) were treated. At 3 years post-loading, implant survival rates were 95.7% (test) and 97.3% (control) and implant success rates were 93.6% and 96.2%, respectively. Mean marginal bone loss was 0.54 (SD 0.26 mm) for the test group and 0.43 (SD 0.22 mm) for the control group. No statistically significant differences between both groups were found. Conclusions Within the limits of this study, implants with peri-implant defects treated with guided bone regeneration exhibited similar survival and success rates and peri-implant marginal bone loss to implants without those defects. Large-scale randomized controlled studies with longer follow-ups involving the assessment of esthetic parameters and hard and soft peri-implant tissue stability are needed. Key words:Guided bone regeneration, peri-implant defects, dental implants, marginal bone level, success rate, survival rate. PMID:26330931

  16. Selective laser sintering of calcium phosphate materials for orthopedic implants

    NASA Astrophysics Data System (ADS)

    Lee, Goonhee

    Two technologies, Solid Freeform Fabrication (SFF) and bioceramics are combined in this work to prepare bone replacement implants with complex geometry. SFF has emerged as a crucial technique for rapid prototyping in the last decade. Selective Laser Sintering (SLS) is one of the established SFF manufacturing processes that can build three-dimensional objects directly from computer models without part-specific tooling or human intervention. Meanwhile, there have been great efforts to develop implantable materials that can assist in regeneration of bone defects and injuries. However, little attention has been focused in shaping bones from these materials. The main thrust of this research was to develop a process that can combine those two separate efforts. The specific objective of this research is to develop a process that can construct bone replacement material of complex geometry from synthetic calcium phosphate materials by using the SLS process. The achievement of this goal can have a significant impact on the quality of health care in the sense that complete custom-fit bone and tooth structures suitable for implantation can be prepared within 24--48 hours of receipt of geometric information obtained either from patient Computed Tomographic (CT) data, from Computer Aided Design (CAD) software or from other imaging systems such as Magnetic Resonance Imaging (MRI) and Holographic Laser Range Imaging (HLRI). In this research, two different processes have been developed. First is the SLS fabrication of porous bone implants. In this effort, systematic procedures have been established and calcium phosphate implants were successfully fabricated from various sources of geometric information. These efforts include material selection and preparation, SLS process parameter optimization, and development of post-processing techniques within the 48-hour time frame. Post-processing allows accurate control of geometry and of the chemistry of calcium phosphate, as well as

  17. [Implantation of the artificial retina].

    PubMed

    Yagi, T; Hayashida, Y

    1999-05-01

    In some degenerative retinal diseases, e.g., retinitis pigmentosa and age-related macular degeneration, the photoreceptors are destroyed to cause serious visual defects. Recent studies on blind human subjects revealed that a large number of ganglion cells remains intact and is capable of transmitting signals to the brain to evoke partial visual perception. This provided hope to compensate for the visual defects with retinal prostheses. The recent progress of microfabrication technique made it possible to implement the Vary Large Scale Integrated circuit, the artificial retina, which emulates a part of retinal function. The idea of implanting the artificial retina to the patients was proposed recently and experiments using animals have been put into practice. This article surveys the front line of the artificial retina implantation.

  18. Microsystem technologies for ophtalmological implants

    NASA Astrophysics Data System (ADS)

    Mokwa, Wilfried

    2003-01-01

    Due to the low power consumption CMOS electronics is ideal for the use in implanted systems. This paper presents two projects working on ophthalmological implants. Both systems are powered by an external RF-field. One system has been developed to measure the intraocular pressure continuously which is important for the therapy of glaucoma patients. The system consists of a micro coil and an integrated pressure transponder chip built into an artificial soft lens. A second example is a very complex system for epiretinal stimulation of the nerve cells of the retina. With such a system it might be possible to give blind people that are suffering from retinitis pigmentosa some visual contact to their surrounding.

  19. Functional fusion of living systems with synthetic electrode interfaces.

    PubMed

    Staufer, Oskar; Weber, Sebastian; Bengtson, C Peter; Bading, Hilmar; Spatz, Joachim P; Rustom, Amin

    2016-01-01

    The functional fusion of "living" biomaterial (such as cells) with synthetic systems has developed into a principal ambition for various scientific disciplines. In particular, emerging fields such as bionics and nanomedicine integrate advanced nanomaterials with biomolecules, cells and organisms in order to develop novel strategies for applications, including energy production or real-time diagnostics utilizing biomolecular machineries "perfected" during billion years of evolution. To date, hardware-wetware interfaces that sample or modulate bioelectric potentials, such as neuroprostheses or implantable energy harvesters, are mostly based on microelectrodes brought into the closest possible contact with the targeted cells. Recently, the possibility of using electrochemical gradients of the inner ear for technical applications was demonstrated using implanted electrodes, where 1.12 nW of electrical power was harvested from the guinea pig endocochlear potential for up to 5 h (Mercier, P.; Lysaght, A.; Bandyopadhyay, S.; Chandrakasan, A.; Stankovic, K. Nat. Biotech. 2012, 30, 1240-1243). More recent approaches employ nanowires (NWs) able to penetrate the cellular membrane and to record extra- and intracellular electrical signals, in some cases with subcellular resolution (Spira, M.; Hai, A. Nat. Nano. 2013, 8, 83-94). Such techniques include nanoelectric scaffolds containing free-standing silicon NWs (Robinson, J. T.; Jorgolli, M.; Shalek, A. K.; Yoon, M. H.; Gertner, R. S.; Park, H. Nat Nanotechnol. 2012, 10, 180-184) or NW field-effect transistors (Qing, Q.; Jiang, Z.; Xu, L.; Gao, R.; Mai, L.; Lieber, C. Nat. Nano. 2013, 9, 142-147), vertically aligned gallium phosphide NWs (Hällström, W.; Mårtensson, T.; Prinz, C.; Gustavsson, P.; Montelius, L.; Samuelson, L.; Kanje, M. Nano Lett. 2007, 7, 2960-2965) or individually contacted, electrically active carbon nanofibers. The latter of these approaches is capable of recording electrical responses from oxidative events

  20. Functional fusion of living systems with synthetic electrode interfaces.

    PubMed

    Staufer, Oskar; Weber, Sebastian; Bengtson, C Peter; Bading, Hilmar; Spatz, Joachim P; Rustom, Amin

    2016-01-01

    The functional fusion of "living" biomaterial (such as cells) with synthetic systems has developed into a principal ambition for various scientific disciplines. In particular, emerging fields such as bionics and nanomedicine integrate advanced nanomaterials with biomolecules, cells and organisms in order to develop novel strategies for applications, including energy production or real-time diagnostics utilizing biomolecular machineries "perfected" during billion years of evolution. To date, hardware-wetware interfaces that sample or modulate bioelectric potentials, such as neuroprostheses or implantable energy harvesters, are mostly based on microelectrodes brought into the closest possible contact with the targeted cells. Recently, the possibility of using electrochemical gradients of the inner ear for technical applications was demonstrated using implanted electrodes, where 1.12 nW of electrical power was harvested from the guinea pig endocochlear potential for up to 5 h (Mercier, P.; Lysaght, A.; Bandyopadhyay, S.; Chandrakasan, A.; Stankovic, K. Nat. Biotech. 2012, 30, 1240-1243). More recent approaches employ nanowires (NWs) able to penetrate the cellular membrane and to record extra- and intracellular electrical signals, in some cases with subcellular resolution (Spira, M.; Hai, A. Nat. Nano. 2013, 8, 83-94). Such techniques include nanoelectric scaffolds containing free-standing silicon NWs (Robinson, J. T.; Jorgolli, M.; Shalek, A. K.; Yoon, M. H.; Gertner, R. S.; Park, H. Nat Nanotechnol. 2012, 10, 180-184) or NW field-effect transistors (Qing, Q.; Jiang, Z.; Xu, L.; Gao, R.; Mai, L.; Lieber, C. Nat. Nano. 2013, 9, 142-147), vertically aligned gallium phosphide NWs (Hällström, W.; Mårtensson, T.; Prinz, C.; Gustavsson, P.; Montelius, L.; Samuelson, L.; Kanje, M. Nano Lett. 2007, 7, 2960-2965) or individually contacted, electrically active carbon nanofibers. The latter of these approaches is capable of recording electrical responses from oxidative events

  1. Silicone Breast Implant and Automatic Implantable Cardioverter Defibrillator: Can They Coexist? A Case Report.

    PubMed

    Or, Friedman; Arik, Zaretski

    2016-08-01

    We present a case of a silicone breast implant rupture after insertion of an automatic implantable cardioverter defibrillator (AICD). A 51-year-old woman presented to our plastic surgery clinic to exchange her silicone breast implants. The patient underwent cosmetic mastopexy and breast augmentation in 2008. Because of recurrent myocardial infarctions and chronic heart failure, she underwent an insertion of an AICD in 2014 in which the left breast implant was hit. In this report, we discuss the first case of an AICD insertion, disrupting a breast implant. This case report illustrates the rare but real possibility of breast implant rupture after even minor surgical manipulation of the breast area. PMID:27622117

  2. Implantable telemetry for small animals

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A series of totally implantable telemetry devices for use in measuring deep body parameters in small animals were developed. Under a collaborative agreement with NASA, several of these systems; the continuous wave Doppler ultrasonic flowmeter, the multichannel telemetry system, and the inductively-powered dual channel cardiac pacer were evaluated in a series of ten mongrel dogs (15 to 20 kg.). These systems were used to measure ascending aortic and coronary blood flow, aortic pressure, and subcutaneous EKG.

  3. Implantable telemetry for small animals

    NASA Astrophysics Data System (ADS)

    1982-03-01

    A series of totally implantable telemetry devices for use in measuring deep body parameters in small animals were developed. Under a collaborative agreement with NASA, several of these systems; the continuous wave Doppler ultrasonic flowmeter, the multichannel telemetry system, and the inductively-powered dual channel cardiac pacer were evaluated in a series of ten mongrel dogs (15 to 20 kg.). These systems were used to measure ascending aortic and coronary blood flow, aortic pressure, and subcutaneous EKG.

  4. Low-Noise Implantable Electrode

    NASA Technical Reports Server (NTRS)

    Lund, G. F.

    1982-01-01

    New implantable electrocardiogram electrode much less sensitive than previous designs to spurious biological potentials. Designed in novel "pocket" configuration, new electrode is intended as sensor for radiotelemetry of biological parameters in experiments on unrestrained subjects. Electrode is esentially squashed cylinder that admits body fluid into interior. Cylinder and electrical lead are made of stainless steel. Spot welding and crimping are used for assembly, rather than soldering.

  5. He reemission implanted in metals

    NASA Astrophysics Data System (ADS)

    Tanabe, T.

    2014-10-01

    Helium (He) reemission of Al, Ni and Mo under energetic He implantation (10-30 keV) in wide temperature range is studied to understand behavior of implanted He in correlation with structure changes. The reemission behavior is categorized into 4 different temperature ranges with the normalized temperature (Tm) to the melting point of each metal. At elevated temperatures (well above ∼0.6 Tm), interstitial He atoms and/or He-vacancy (ies) clusters can migrate remaining no structure change and showing smooth reemission without any burst. Between ∼0.25 and 0.6 Tm, He reemission always accompanies significant structure modification. For ∼04-0.6 Tm, implanted He coalesce to make bubbles and the bubbles can move to the surface. Bubble migration accompanies materials flow to the surface resulting in fuzz surface or columnar structure, depending on implantation flux. Slower bubble motion at ∼0.25-0.4 prohibits the material migration. Instead the bubbles coalesce to grow large and multi-layered blistering appears as periodic reemission behavior. Below ∼0.25 Tm, He migration is too slow for bubbles to grow large, but bubble density increases up to a certain fluence, where neighboring bubbles start to coalesce. Accordingly, He release is mostly caused by mechanical failure or blister rapture. With increasing fluence, all defects (bubbles and dislocation loops) tangle or inter connected with neighboring defects and accordingly He migration to the surface along the tangled or connected defects is enhanced, resulting 100% reemission easily without making multilayered blistering.

  6. Laser bioengineering of glass-titanium implants surface

    NASA Astrophysics Data System (ADS)

    Lusquiños, F.; Arias-González, F.; Penide, J.; del Val, J.; Comesaña, R.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pascual, M. J.; Durán, A.; Pou, J.

    2013-11-01

    Osseointegration is the mean challenge when surgical treatments fight against load-bearing bone diseases. Absolute bone replacement by a synthetic implant has to be completed not only from the mechanics point of view, but also from a biological approach. Suitable strength, resilience and stress distribution of titanium alloy implants are spoiled by the lack of optimal biological characteristics. The inert quality of extra low interstitial titanium alloy, which make it the most attractive metallic alloy for biomedical applications, oppose to an ideal surface with bone cell affinity, and capable to stimulate bone attachment bone growth. Diverse laser treatments have been proven as effective tools to modify surface properties, such as wettability in contact to physiological fluids, or osteoblast guided and slightly enhanced attachment. The laser surface cladding can go beyond by providing titanium alloy surfaces with osteoconduction and osteoinduction properties. In this research work, the laser radiation is used to produce bioactive glass coatings on Ti6Al4V alloy substrates. Specific silicate bioactive glass compositions has been investigated to achieve suitable surface tension and viscosity temperature behavior during processing, and to provide with the required release of bone growth gene up regulation agents in the course of resorption mediated by physiological fluids. The produced coatings and interfaces, the surface osteoconduction properties, and the chemical species release in simulated physiological fluid were characterized by scanning electron microscopy (SEM), hot stage microscopy (HSM), X-ray diffraction (XRD), X ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR).

  7. Effects of the Synthetic Neurosteroid

    PubMed Central

    Parésys, Lucie; Hoffmann, Kerstin; Bianchi, Massimiliano; Villey, Isabelle; Baulieu, Etienne-Emile; Fuchs, Eberhard

    2016-01-01

    Background: Most currently available active antidepressant drugs are selective serotonin/noradrenaline reuptake inhibitors. However, as their clinical efficacy is not immediate, long-term administration is often accompanied by substantial side effects, and numerous patients remain non- or partial responders. We have recently found that the synthetic neurosteroid derivative 3β-methoxypregnenolone, which binds to the microtubule-associated protein-2, can provide a novel therapeutic approach in experimental model of depressive disorders in rats. To further validate the antidepressant-like efficacy of 3β-methoxypregnenolone, we investigated effects of a longer treatment (4-week oral administration; 50mg/kg/d) in a nonrodent species, the tree shrew, exposed to psychosocial stress that elicits close-to-human alterations observed in patients with depressive disorders. Methods: During the experimental period, physiological parameters were registered, including core body temperature and electroencephalogram, while animals were videotaped to analyze their avoidance behavior. Morning urine samples were collected for measurements of cortisol and noradrenaline levels. Results: We found that treatment with 3β-methoxypregnenolone abolished stress-triggered avoidance behavior and prevented hormone hypersecretion, hypothermia, and sleep disturbances, further suggesting its antidepressant-like efficacy. Comparative treatment with fluoxetine also prevented some of the physiological alterations, while the hypersecretion of cortisol and sleep disturbances were not or partially restored by fluoxetine, suggesting a better efficacy of 3β-methoxypregnenolone. Alpha-tubulin isoforms were measured in hippocampi: we found that 3β-methoxypregnenolone reversed the specific decrease in acetylation of α-tubulin induced by psychosocial stress, while it did not modify the psychosocial stress-elicited reduction of tyrosinated α-tubulin. Conclusions: Taken together, these data strongly suggest

  8. New synthetic drugs in addictovigilance.

    PubMed

    Chavant, François; Boucher, Alexandra; Le Boisselier, Reynald; Deheul, Sylvie; Debruyne, Danièle

    2015-01-01

    New substances, also known as "designer drugs" or "legal highs" are increasingly available to drug users. Two hundred and fifteen hitherto unlisted substances have been notified by European Union member states since 2005. These synthetic drugs, which have been developed to side-step the legislation on drugs, are analogues or derivatives of existing drugs and medications. The availability of these "legal highs", sold on Internet under various denominations such as bath salt, plant fertilizer, chemical not intended for human use, or spice, is unlimited. The effects felt by users vary, and the substances may be stimulant, entactogenic, hallucinogenic, psychedelic or dissociative. The pharmacological targets also vary, and may be either the increase of extracellular levels of neurotransmitters via different mechanisms (reuptake inhibition, stimulation of intracellular release) or else fixation on specific receptors. Several chemical classes, themselves divided into sub-classes, are involved: phenethylamines, tryptamines, piperazines, cathinones, cannabinoids etc. The toxicity of the main members of these categories is increasingly well known, the most deleterious being behavioural effects, physical manifestations, and cardiovascular consequences. However, small variations in their chemical structure can generate effects that are quantitatively different, thus enhancing their toxicity or addictive potential, and much remains to be achieved in terms of knowledge about these new drugs. These substances are indeed present on the French territory, as shown by data provided by the Observatoire Français des Drogues et Toxicomanies, and notifications by the French Addictovigilance network. Screening in clinical toxicology laboratories is not widespread, since these molecules are not detected by the standard screening tests, so that there is probably an under-estimation of the use of these new drugs. The legislation on these substances changes regularly, with more and more

  9. Bacterial Adhesion at Synthetic Surfaces

    PubMed Central

    Cunliffe, D.; Smart, C. A.; Alexander, C.; Vulfson, E. N.

    1999-01-01

    A systematic investigation into the effect of surface chemistry on bacterial adhesion was carried out. In particular, a number of physicochemical factors important in defining the surface at the molecular level were assessed for their effect on the adhesion of Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, and Escherichia coli. The primary experiments involved the grafting of groups varying in hydrophilicity, hydrophobicity, chain length, and chemical functionality onto glass substrates such that the surfaces were homogeneous and densely packed with functional groups. All of the surfaces were found to be chemically well defined, and their measured surface energies varied from 15 to 41 mJ · m−2. Protein adsorption experiments were performed with 3H-labelled bovine serum albumin and cytochrome c prior to bacterial attachment studies. Hydrophilic uncharged surfaces showed the greatest resistance to protein adsorption; however, our studies also showed that the effectiveness of poly(ethyleneoxide) (PEO) polymers was not simply a result of its hydrophilicity and molecular weight alone. The adsorption of the two proteins approximately correlated with short-term cell adhesion, and bacterial attachment for L. monocytogenes and E. coli also correlated with the chemistry of the underlying substrate. However, for S. aureus and S. typhimurium a different pattern of attachment occurred, suggesting a dissimilar mechanism of cell attachment, although high-molecular-weight PEO was still the least-cell-adsorbing surface. The implications of this for in vivo attachment of cells suggest that hydrophilic passivating groups may be the best method for preventing cell adsorption to synthetic substrates provided they can be grafted uniformly and in sufficient density at the surface. PMID:10543814

  10. Synthetic biology: mapping the scientific landscape.

    PubMed

    Oldham, Paul; Hall, Stephen; Burton, Geoff

    2012-01-01

    This article uses data from Thomson Reuters Web of Science to map and analyse the scientific landscape for synthetic biology. The article draws on recent advances in data visualisation and analytics with the aim of informing upcoming international policy debates on the governance of synthetic biology by the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) of the United Nations Convention on Biological Diversity. We use mapping techniques to identify how synthetic biology can best be understood and the range of institutions, researchers and funding agencies involved. Debates under the Convention are likely to focus on a possible moratorium on the field release of synthetic organisms, cells or genomes. Based on the empirical evidence we propose that guidance could be provided to funding agencies to respect the letter and spirit of the Convention on Biological Diversity in making research investments. Building on the recommendations of the United States Presidential Commission for the Study of Bioethical Issues we demonstrate that it is possible to promote independent and transparent monitoring of developments in synthetic biology using modern information tools. In particular, public and policy understanding and engagement with synthetic biology can be enhanced through the use of online interactive tools. As a step forward in this process we make existing data on the scientific literature on synthetic biology available in an online interactive workbook so that researchers, policy makers and civil society can explore the data and draw conclusions for themselves.

  11. Synthetic Biology: Mapping the Scientific Landscape

    PubMed Central

    Oldham, Paul; Hall, Stephen; Burton, Geoff

    2012-01-01

    This article uses data from Thomson Reuters Web of Science to map and analyse the scientific landscape for synthetic biology. The article draws on recent advances in data visualisation and analytics with the aim of informing upcoming international policy debates on the governance of synthetic biology by the Subsidiary Body on Scientific, Technical and Technological Advice (SBSTTA) of the United Nations Convention on Biological Diversity. We use mapping techniques to identify how synthetic biology can best be understood and the range of institutions, researchers and funding agencies involved. Debates under the Convention are likely to focus on a possible moratorium on the field release of synthetic organisms, cells or genomes. Based on the empirical evidence we propose that guidance could be provided to funding agencies to respect the letter and spirit of the Convention on Biological Diversity in making research investments. Building on the recommendations of the United States Presidential Commission for the Study of Bioethical Issues we demonstrate that it is possible to promote independent and transparent monitoring of developments in synthetic biology using modern information tools. In particular, public and policy understanding and engagement with synthetic biology can be enhanced through the use of online interactive tools. As a step forward in this process we make existing data on the scientific literature on synthetic biology available in an online interactive workbook so that researchers, policy makers and civil society can explore the data and draw conclusions for themselves. PMID:22539946

  12. Dental Implants Installed in Irradiated Jaws

    PubMed Central

    Chambrone, L.; Mandia, J.; Shibli, J.A.; Romito, G.A.; Abrahao, M.

    2013-01-01

    The aim of this study was to assess the survival rate of titanium implants placed in irradiated jaws. MEDLINE, EMBASE, and CENTRAL were searched for studies assessing implants that had been placed in nongrafted sites of irradiated patients. Random effects meta-analyses assessed implant loss in irradiated versus nonirradiated patients and in irradiated patients treated with hyperbaric oxygen (HBO) therapy. Of 1,051 potentially eligible publications, 15 were included. A total of 10,150 implants were assessed in the included studies, and of these, 1,689 (14.3%) had been placed in irradiated jaws. The mean survival rate in the studies ranged from 46.3% to 98.0%. The pooled estimates indicated a significant increase in the risk of implant failure in irradiated patients (risk ratio: 2.74; 95% confidence interval: 1.86, 4.05; p < .00001) and in maxillary sites (risk ratio: 5.96; 95% confidence interval: 2.71, 13.12; p < .00001). Conversely, HBO therapy did not reduce the risk of implant failure (risk ratio: 1.28; 95% confidence interval: 0.19, 8.82; p = .80). Radiotherapy was linked to higher implant failure in the maxilla, and HBO therapy did not improve implant survival. Most included publications reported data on machined implants, and only 3 studies on HBO therapy were included. Overall, implant therapy appears to be a viable treatment option for reestablishing adequate occlusion and masticatory conditions in irradiated patients. PMID:24158336

  13. Miniscrew implant applications in contemporary orthodontics.

    PubMed

    Chang, Hong-Po; Tseng, Yu-Chuan

    2014-03-01

    The need for orthodontic treatment modalities that provide maximal anchorage control but with minimal patient compliance requirements has led to the development of implant-assisted orthodontics and dentofacial orthopedics. Skeletal anchorage with miniscrew implants has no patient compliance requirements and has been widely incorporated in orthodontic practice. Miniscrew implants are now routinely used as anchorage devices in orthodontic treatment. This review summarizes recent data regarding the interpretation of bone data (i.e., bone quantity and quality) obtained by preoperative diagnostic computed tomography (CT) or by cone-beam computed tomography (CBCT) prior to miniscrew implant placement. Such data are essential when selecting appropriate sites for miniscrew implant placement. Bone characteristics that are indications and contraindications for treatment with miniscrew implants are discussed. Additionally, bicortical orthodontic skeletal anchorage, risks associated with miniscrew implant failure, and miniscrew implants for nonsurgical correction of occlusal cant or vertical excess are reviewed. Finally, implant stability is compared between titanium alloy and stainless steel miniscrew implants. PMID:24581210

  14. Computerized implant-dentistry: Advances toward automation.

    PubMed

    Gulati, Minkle; Anand, Vishal; Salaria, Sanjeev Kumar; Jain, Nikil; Gupta, Shilpi

    2015-01-01

    Advancements in the field of implantology such as three-dimensional imaging, implant-planning software, computer-aided-design/computer-aided-manufacturing (CAD/CAM) technology, computer-guided, and navigated implant surgery have led to the computerization of implant-dentistry. This three-dimensional computer-generated implant-planning and surgery has not only enabled accurate preoperative evaluation of the anatomic limitations but has also facilitated preoperative planning of implant positions along with virtual implant placement and subsequently transferring the virtual treatment plans onto the surgical phase via static (guided) or dynamic (navigated) systems aided by CAD/CAM technology. Computerized-implant-dentistry being highly predictable and minimally invasive in nature has also allowed implant placement in patients with medical comorbidities (e.g. radiation therapy, blood dyscrasias), in patients with complex problems following a significant alteration of the bony anatomy as a result of benign or malignant pathology of the jaws or trauma and in patients with other physical and emotional problems. With significant achievements accomplished in the field of computerized implant-dentistry, attempts are now been made toward complete automation of implant-dentistry. PMID:25810585

  15. Cochlear Implantation in Unique Pediatric Populations

    PubMed Central

    Hang, Anna X.; Kim, Grace G.; Zdanski, Carlton J.

    2012-01-01

    Purpose of review Over the last decade, the selection criteria for cochlear implantation have expanded to include children with special auditory, otologic, and medical problems. Included within this expanded group of candidates are those children with auditory neuropathy spectrum disorder, cochleovestibular malformations, cochlear nerve deficiency, associated syndromes, as well as multiple medical and developmental disorders. Definitive indications for cochlear implantation in these unique pediatric populations are in evolution. This review will provide an overview of managing and habilitating hearing loss within these populations with specific focus on cochlear implantation as a treatment option. Recent findings Cochlear implants have been successfully implanted in children within unique populations with variable results. Evaluation for cochlear implant candidacy includes the core components of a full medical, audiologic, and speech and language evaluations. When considering candidacy in these children, additional aspects to consider include disorder specific surgical considerations and child/care-giver counseling regarding reasonable post-implantation outcome expectations. Summary Cochlear implantations are accepted as the standard of care for improving hearing and speech development in children with severe to profound hearing loss. However, children with sensorineural hearing loss who meet established audiologic criteria for cochlear implantation may have unique audiologic, medical, and anatomic characteristics that necessitate special consideration regarding cochlear implantation candidacy and outcome. Individualized pre-operative candidacy and counseling, surgical evaluation, and reasonable post-operative outcome expectations should be taken into account in the management of these children. PMID:23128686

  16. Exposed Dental Implant? Local Autograft A Saviour!

    PubMed Central

    Rai, Raj; Punde, Prashant A; Suryavanshi, Harshal; Shree, Swetha

    2015-01-01

    Implant exposure due to faulty placement, posses as the most common reason for implant failure. The implant placed too close to buccal or lingual cortex have lead to such failure on numerous occasions. Also, anatomic variations like the thin buccolingual width of alveolar ridge predispose exposure of the implant. 25-year-old female patient had undergone surgical placement of implants in mandibular anterior region 2 months back in the private dental clinic. The clinician noted Grade I mobility in one of the implants placed. The case was referred to the author. Thin overlying gingiva depicted an entire buccal aspect of the implant, which suggested more than 90 % loss of buccal cortex. According to literature and review of similar case reports, the only way suggested was to surgically remove the implant and wait for 12-24 months for the bone to heal for subsequent placement. Rather than the removal of implants as suggested, the author followed a naval approach of reinforcing buccal cortex using an autogenous cortical block from mandibular symphysis. The reinforcement surgery had certainly saved patients time, money and most importantly limits a crucial period of edentulism, which may be enforced on a patient in case the implant was removed. PMID:26668490

  17. Computerized implant-dentistry: Advances toward automation

    PubMed Central

    Gulati, Minkle; Anand, Vishal; Salaria, Sanjeev Kumar; Jain, Nikil; Gupta, Shilpi

    2015-01-01

    Advancements in the field of implantology such as three-dimensional imaging, implant-planning software, computer-aided-design/computer-aided-manufacturing (CAD/CAM) technology, computer-guided, and navigated implant surgery have led to the computerization of implant-dentistry. This three-dimensional computer-generated implant-planning and surgery has not only enabled accurate preoperative evaluation of the anatomic limitations but has also facilitated preoperative planning of implant positions along with virtual implant placement and subsequently transferring the virtual treatment plans onto the surgical phase via static (guided) or dynamic (navigated) systems aided by CAD/CAM technology. Computerized-implant-dentistry being highly predictable and minimally invasive in nature has also allowed implant placement in patients with medical comorbidities (e.g. radiation therapy, blood dyscrasias), in patients with complex problems following a significant alteration of the bony anatomy as a result of benign or malignant pathology of the jaws or trauma and in patients with other physical and emotional problems. With significant achievements accomplished in the field of computerized implant-dentistry, attempts are now been made toward complete automation of implant-dentistry. PMID:25810585

  18. Subgingival microbiome in patients with healthy and ailing dental implants

    PubMed Central

    Zheng, Hui; Xu, Lixin; Wang, Zicheng; Li, Lianshuo; Zhang, Jieni; Zhang, Qian; Chen, Ting; Lin, Jiuxiang; Chen, Feng

    2015-01-01

    Dental implants are commonly used to replace missing teeth. However, the dysbiotic polymicrobial communities of peri-implant sites are responsible for peri-implant diseases, such as peri-implant mucositis and peri-implantitis. In this study, we analyzed the microbial characteristics of oral plaque from peri-implant pockets or sulci of healthy implants (n = 10), peri-implant mucositis (n = 8) and peri-implantitis (n = 6) sites using pyrosequencing of the 16S rRNA gene. An increase in microbial diversity was observed in subgingival sites of ailing implants, compared with healthy implants. Microbial co-occurrence analysis revealed that periodontal pathogens, such as Porphyromonas gingivalis, Tannerella forsythia, and Prevotella intermedia, were clustered into modules in the peri-implant mucositis network. Putative pathogens associated with peri-implantitis were present at a moderate relative abundance in peri-implant mucositis, suggesting that peri-implant mucositis an important early transitional phase during the development of peri-implantitis. Furthermore, the relative abundance of Eubacterium was increased at peri-implantitis locations, and co-occurrence analysis revealed that Eubacterium minutum was correlated with Prevotella intermedia in peri-implantitis sites, which suggests the association of Eubacterium with peri-implantitis. This study indicates that periodontal pathogens may play important roles in the shifting of healthy implant status to peri-implant disease. PMID:26077225

  19. Miniaturized neural interfaces and implants

    NASA Astrophysics Data System (ADS)

    Stieglitz, Thomas; Boretius, Tim; Ordonez, Juan; Hassler, Christina; Henle, Christian; Meier, Wolfgang; Plachta, Dennis T. T.; Schuettler, Martin

    2012-03-01

    Neural prostheses are technical systems that interface nerves to treat the symptoms of neurological diseases and to restore sensory of motor functions of the body. Success stories have been written with the cochlear implant to restore hearing, with spinal cord stimulators to treat chronic pain as well as urge incontinence, and with deep brain stimulators in patients suffering from Parkinson's disease. Highly complex neural implants for novel medical applications can be miniaturized either by means of precision mechanics technologies using known and established materials for electrodes, cables, and hermetic packages or by applying microsystems technologies. Examples for both approaches will be introduced and discussed. Electrode arrays for recording of electrocorticograms during presurgical epilepsy diagnosis have been manufactured using approved materials and a marking laser to achieve an integration density that is adequate in the context of brain machine interfaces, e.g. on the motor cortex. Microtechnologies have to be used for further miniaturization to develop polymer-based flexible and light weighted electrode arrays to interface the peripheral and central nervous system. Polyimide as substrate and insulation material will be discussed as well as several application examples for nerve interfaces like cuffs, filament like electrodes and large arrays for subdural implantation.

  20. Tissue response to peritoneal implants

    NASA Technical Reports Server (NTRS)

    Picha, G. J.

    1980-01-01

    Peritoneal implants were fabricated from poly 2-OH, ethyl methacrylate (HEMA), polyetherurethane (polytetramethylene glycol 1000 MW, 1,4 methylene disocynate, and ethyl diamine), and untreated and sputter treated polytetrafluoroethylene (PTFE). The sputter treated PTFE implants were produced by an 8 cm diameter argon ion source. The treated samples consisted of ion beam sputter polished samples, sputter etched samples (to produce a microscopic surface cone texture) and surface pitted samples (produced by ion beam sputtering to result in 50 microns wide by 100 microns deep square pits). These materials were implanted in rats for periods ranging from 30 minutes to 14 days. The results were evaluated with regard to cell type and attachment kinetics onto the different materials. Scanning electron microscopy and histological sections were also evaluated. In general the smooth hydrophobic surfaces attracted less cells than the ion etched PTFE or the HEMA samples. The ion etching was observed to enhance cell attachment, multinucleated giant cell (MNGC) formation, cell to cell contact, and fibrous capsule formation. The cell responsed in the case of ion etched PTFE to an altered surface morphology. However, equally interesting was the similar attachment kinetics of HEMA verses the ion etched PTFE. However, HEMA resulted in a markedly different response with no MNGC's formation, minimal to no capsule formation, and sample coverage by a uniform cell layer.