WorldWideScience

Sample records for active laser media

  1. Nonlinear processes in laser heating of chemically active media

    Energy Technology Data Exchange (ETDEWEB)

    Bunkin, F V; Kirichenko, N A; Luk' yanchuk, B S

    1984-08-01

    After it had been discovered and in due measure physically comprehended that numerous nontrivial phenomena observed during laser heating of chemically active media are caused primarily by self-stress of laser radiation due to the chemical intertial nonlinearity of the medium, an approach was found for solving problems of laser thermochemistry that is most adequate from the mathematical (and physical) standpoint: the approach of the theory of nonlinear oscillations in point systems and distributed systems. This approach has provided a uniform viewpoint for examination of a variety of phenomena of spatiotemporal self-organization of chemically active media under the effect of laser radiation, qualitative, and in some cases quantitative description of such phenomena as the onset of thermochemical instability, self-oscillations, various spatial structures and the like. Evidently it can be rightly considered that at this juncture a definite stage has been completed in the development of laser thermochemistry marked by the creation of an ideology, method and overall approach to interpretation of the most diverse phenomena under conditions of actual physical experiments. References to the numerous studies that make up the content of this stage of development of laser thermochemistry are to be found in survey papers. 48 references, 10 figures.

  2. High power diode pumped solid state (DPSS) laser systems active media robust modeling and analysis

    Science.gov (United States)

    Kashef, Tamer M.; Mokhtar, Ayman M.; Ghoniemy, Samy A.

    2018-02-01

    Diode side-pumped solid-state lasers have the potential to yield high quality laser beams with high efficiency and reliability. This paper summarizes the results of simulation of the most predominant active media that are used in high power diode pumped solid-state (DPSS) laser systems. Nd:YAG, Nd:glass, and Nd:YLF rods laser systems were simulated using the special finite element analysis software program LASCAD. A performance trade off analysis for Nd:YAG, Nd:glass, and Nd:YLF rods was performed in order to predict the system optimized parameters and to investigate thermally induced thermal fracture that may occur due to heat load and mechanical stress. The simulation results showed that at the optimized values Nd:YAG rod achieved the highest output power of 175W with 43% efficiency and heat load of 1.873W/mm3. A negligible changes in laser output power, heat load, stress, and temperature distributions were observed when the Nd:YAG rod length was increased from 72 to 80mm. Simulation of Nd:glass at different rod diameters at the same pumping conditions showed better results for mechanical stress and thermal load than that of Nd:YAG and Nd:YLF which makes it very suitable for high power laser applications especially for large rod diameters. For large rod diameters Nd:YLF is mechanically weaker and softer crystal compared to Nd:YAG and Nd:glass due to its poor thermomechanical properties which limits its usage to only low to medium power systems.

  3. Status and trends of short pulse generation using mode-locked lasers based on advanced quantum-dot active media

    International Nuclear Information System (INIS)

    Shi, L W; Chen, Y H; Xu, B; Wang, Z C; Jiao, Y H; Wang, Z G

    2007-01-01

    In this review, the potential of mode-locked lasers based on advanced quantum-dot (QD) active media to generate short optical pulses is analysed. A comprehensive review of experimental and theoretical work on related aspects is provided, including monolithic-cavity mode-locked QD lasers and external-cavity mode-locked QD lasers, as well as mode-locked solid-state and fibre lasers based on QD semiconductor saturable absorber mirrors. Performance comparisons are made for state-of-the-art experiments. Various methods for improving important characteristics of mode-locked pulses such as pulse duration, repetition rate, pulse power, and timing jitter through optimization of device design parameters or mode-locking methods are addressed. In addition, gain switching and self-pulsation of QD lasers are also briefly reviewed, concluding with the summary and prospects. (topical review)

  4. Laser radiation in active amplifying media treated as a transport problem - Transfer equation derived and exactly solved

    Science.gov (United States)

    Gupta, S. R. D.; Gupta, Santanu D.

    1991-10-01

    The flow of laser radiation in a plane-parallel cylindrical slab of active amplifying medium with axial symmetry is treated as a problem in radiative transfer. The appropriate one-dimensional transfer equation describing the transfer of laser radiation has been derived by an appeal to Einstein's A, B coefficients (describing the processes of stimulated line absorption, spontaneous line emission, and stimulated line emission sustained by population inversion in the medium) and considering the 'rate equations' to completely establish the rational of the transfer equation obtained. The equation is then exactly solved and the angular distribution of the emergent laser beam intensity is obtained; its numerically computed values are given in tables and plotted in graphs showing the nature of peaks of the emerging laser beam intensity about the axis of the laser cylinder.

  5. Laser beam propagation in nonlinear optical media

    CERN Document Server

    Guha, Shekhar

    2013-01-01

    ""This is very unique and promises to be an extremely useful guide to a host of workers in the field. They have given a generalized presentation likely to cover most if not all situations to be encountered in the laboratory, yet also highlight several specific examples that clearly illustrate the methods. They have provided an admirable contribution to the community. If someone makes their living by designing lasers, optical parametric oscillators or other devices employing nonlinear crystals, or designing experiments incorporating laser beam propagation through linear or nonlinear media, then

  6. Laser treatment of otitis media in children

    Energy Technology Data Exchange (ETDEWEB)

    Podoynitsyna, L.F.

    1984-08-01

    Clinical trials were conducted with the helium-neon LG-75 laser (632.8 nm, 0.1 W/cm/sup 2/) in the management of 50 children with acute and chronic otitis media. The sessions consisted of 30 sec irradiation directed at the middle ear through the external meatus for a period of 5 days. Positive results were obtained in 45 of the patients with cessation of discharge on the 2nd or 3rd day, and return of hearing by the end of the week. The remission was not permanent in one patient with recurrent otitis media. These observations indicate that the anti-inflammatory effects of helium-neon irradiation constitute an effective treatment modality in children with otitis media. 6 references.

  7. Media Activism in XXIst Century

    Directory of Open Access Journals (Sweden)

    Tutu Pisleag

    2013-11-01

    Full Text Available The new instruments and means in social media practically reinvented the social activism and the “activists” are better defined through these means than by the causes they manifest for. The easy auto organization through social media opens the possibility that the one involved to manifest in real time, more efficiently, in national, regional or global sized spaces.

  8. Audience Activity and Media Use.

    Science.gov (United States)

    Rubin, Alan M.

    1993-01-01

    Explores a view of audience behavior that lies between the extremes of a passive audience expected to be influenced by communication messages and an active audience expected to make rational decisions about what media content to accept and reject. (RS)

  9. Laser activated superconducting switch

    International Nuclear Information System (INIS)

    Wolf, A.A.

    1976-01-01

    A superconducting switch or bistable device is described consisting of a superconductor in a cryogen maintaining a temperature just below the transition temperature, having a window of the proper optical frequency band for passing a laser beam which may impinge on the superconductor when desired. The frequency of the laser is equal to or greater than the optical absorption frequency of the superconducting material and is consistent with the ratio of the gap energy of the switch material to Planck's constant, to cause depairing of electrons, and thereby normalize the superconductor. Some embodiments comprise first and second superconducting metals. Other embodiments feature the two superconducting metals separated by a thin film insulator through which the superconducting electrons tunnel during superconductivity

  10. Laser Myringotomy Versus Ventilation Tubes In Otitis Media With Effusion.

    Science.gov (United States)

    Yousaf, Mohammad; Malik, Suhail Ahmad; Haroon, Tahir

    2016-01-01

    Otitis media with effusion (OME) is a leading cause of difficulty in hearing in paediatric population. Otitis media with effusion must be detected and managed early to prevent conductive hearing loss in children. It was aimed to compare results of laser myringotomy and ventilation tube insertion, in terms of hearing improvement and recurrence of Middle ear effusion (MEE). This randomized controlled trial was conducted from February 2012 to January 2015. Children of 4- 12 years of age with decreased hearing due to OME were included in the study. These children were investigated with pure tone audiometry (PTA) and tympanometry to confirm conductive hearing loss. Patients were put in 2 groups, group one comprised of patients treated with laser myringotomy and group 2, treated with ventilation tube insertion. The objective was to evaluate and compare results of the two procedures in terms of resolution of middle ear effusion (MEE) and improvement of hearing. The two procedures were also compared in terms of complications like otorrhea, persistence of perforation, hypertrophic scar and thinning of tympanic membrane (TM). Middle ear effusion cleared in 35 out of 68 ears with laser myringotomy (LM) as compared to 52 out of 62 ears with ventilation tubes (VT). The myringotomy was still patent in 21 ears treated with LM while tube was in site in 50 years with VT after 3 months. The hearing level improved with LM by 10-15 dB after first 3 months. The aim in Otitis media with effusion is ventilation of tympanic cavity. Laser myringotomy can be substitute to ventilation tube insertion (VT). But it remains patent for shorter time and less effective than VT. The ears with refractory or recurrent MEE should have VT insertion.

  11. Nuclear activated cw chemical laser

    International Nuclear Information System (INIS)

    Roberts, T.G.

    1982-01-01

    A cw chemical laser which uses processed radioactive waste to produce active atoms from a chemically inactive gas before being mixed with another molecule such as hydrogen or deuterium is disclosed. This laser uses no toxic or corrosive fuels and does not require any electrical or other type of auxiliary power supply. The energy released by the radioactive material is used to produce the active atoms such as fluorine. This is accomplished by using the radiation products from processed radioactive waste to dissociate the inert gas in the plenum of the laser. The radioactive material is held in the passageway walls of a device similar to a heat exchanger. The exchanger device may be located in the gas generator section of a chemical laser. The inactive gas is passed through the exchanger device and while passing through it the radiation from the radioactive material dissociates the gas, producing a concentration of free active atoms. This active atom generator then feeds the nozzle bank or mixing section of a laser to produce a lasing action

  12. Nuclear fission fragment excitation of electronic transition laser media

    International Nuclear Information System (INIS)

    Lorents, D.C.; McCusker, M.V.; Rhodes, C.K.

    1976-01-01

    The properties of high energy electronic transition lasers excited by fission fragments are expanded. Specific characteristics of the media including density, excitation rates, wavelength, kinetics, fissile material, scale size, and medium uniformity are assessed. The use of epithermal neutrons, homogeneously mixed fissile material, and special high cross section nuclear isotopes to optimize coupling of the energy to the medium are shown to be important considerations maximizing the scale size, energy deposition, and medium uniformity. A performance limit point of approximately 1000 J/l in approximately 100 μs pulses is established for a large class of systems operating in the near ultraviolet and visible spectral regions. It is demonstrated that e-beam excitation can be used to simulate nuclear pumping conditions to facilitate the search for candidate media. Experimental data for the kinetics of a XeF* laser operating in Ar/Xe/F 2 /UF 6 mixtures are given. These reactor-pumped systems are suitable for scaling to volumes on the order of (meters) 3

  13. Nonlinear propagation of ultrashort laser pulses in transparent media

    International Nuclear Information System (INIS)

    Vincotte, A.

    2006-10-01

    We present different aspects of the propagation of ultrashort laser pulses in transparent media. First, we derive the propagation equations starting from the Maxwell equations. We remind of the main physical phenomena undergone by ultrashort and powerful laser pulses. First self-focusing occurs, owing to the Kerr response of the medium. This self-focusing is stopped by plasma generation from the laser-induced ionization of the ambient atoms. The propagation of the wave generates a super-continuum through self-phase modulation. We recall the main results concerning the simple and multiple filamentation of an intense wave, induced by the beam inhomogeneities and which take place as soon as the beam power is above critical. In a second part, we investigate the influence of high-order nonlinearities on the propagation of the beam and especially on its filamentation pattern. To control the multi-filamentation process, we investigate in a third part the propagation of beams with special designs, namely; Gradient- and vortex-shaped beams. We justify the robustness of this latter kind of optical objects. Eventually, we investigate multi-filamentation patterns of femtosecond pulses in a fog tube and in cells of ethanol doped with coumarin, for different beam configurations. (author)

  14. High intensive short laser pulse interaction with submicron clusters media

    International Nuclear Information System (INIS)

    Faenov, A. Ya

    2008-01-01

    The interaction of short intense laser pulses with structured targets, such as clusters, exhibits unique features, stemming from the enhanced absorption of the incident laser light compared to solid targets. Due to the increased absorption, these targets are heated significantly, leading to enhanced emission of x rays in the keV range and generation of electrons and multiple charged ions with kinetic energies from tens of keV to tens of MeV. Possible applications of these targets can be an electron/ion source for a table top accelerator, a neutron source for a material damage study, or an x ray source for microscopy or lithography. The overview of recent results, obtained by the high intensive short laser pulse interaction with different submicron clusters media will be presented. High resolution K and L shell spectra of plasma generated by superintense laser irradiation of micron sized Ar, Kr and Xe clusters have been measured with intensity 10"17"-10"19"W/cm"2"and a pulse duration of 30-1000fs. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance toward the higher charge states, which enhances both the X ray line yield and the ion kinetic energy. Irradiation of clusters, produced from such gas mixture, by a fs Ti:Sa laser pulses allows to enhance the soft X ray radiation of Heβ(665.7eV)and Lyα(653.7eV)of Oxygen in 2-8 times compare with the case of using as targets pure CO"2"or N"2"O clusters and reach values 2.8x10"10"(∼3μJ)and 2.7x10"10"(∼2.9μJ)ph/(sr·pulse), respectively. Nanostructure conventional soft X ray images of 100nm thick Mo and Zr foils in a wide field of view (cm"2"scale)with high spatial resolution (700nm)are obtained using the LiF crystals as soft X ray imaging detectors. When the target used for the ion acceleration studies consists of solid density clusters embedded into the background gas, its irradiation by high intensity laser light makes the target

  15. Gain media edge treatment to suppress amplified spontaneous emission in a high power laser

    Science.gov (United States)

    Hackel, Lloyd A.; Soules, Thomas F.; Fochs, Scott N.; Rotter, Mark D.; Letts, Stephan A.

    2008-12-09

    A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges using a substantially high index bonding elastomer or epoxy to a predetermined electromagnetic absorbing arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

  16. Envelope evolution of a laser pulse in an active medium

    International Nuclear Information System (INIS)

    Fisher, D.L.; Tajima, T.; Downer, M.C.; Siders, C.W.

    1994-11-01

    The authors show that the envelope velocity, v env , of a short laser pulse can, via propagation in an active medium, be made less than, equal to, or even greater than c, the vacuum phase velocity of light. Simulation results, based on moving frame propagation equations coupling the laser pulse, active medium and plasma, are presented, as well as equations that determines the design value of super- and sub-luminous v env . In this simulation the laser pulse evolves in time in a moving frame as opposed to their earlier work where the profile was fixed. The elimination of phase slippage and pump depletion effects in the laser wakefield accelerator is discussed as a particular application. Finally they discuss media properties necessary for an experimental realization of this technique

  17. Turbid Media Extinction Coefficient for Near-Infrared Laser Radiation

    International Nuclear Information System (INIS)

    Dreischuh, T; Gurdev, L; Vankov, O; Stoyanov, D; Avramov, L

    2015-01-01

    In this work, extended investigations are performed of the extinction coefficient of Intralipid-20% dilutions in distilled water depending on the Intralipid concentration, for laser radiation wavelengths in the red and near-infrared regions covering the so-called tissue optical window. The extinction is measured by using an approach we have developed recently based on the features of the spatial intensity distribution of laser-radiation beams propagating through semi-infinite turbid media. The measurements are conducted using separately two dilution- containing plexiglass boxes of different sizes and volumes, in order to prove the appropriateness of the assumption of semi-infinite turbid medium. The experimental results for the extinction are in agreement with our previous results and with empiric formulae found by other authors concerning the wavelength dependence of the scattering coefficient of Intralipid – 10% and Intralipid – 20%. They are also in agreement with known data of the water absorptance. It is estimated as well that the wavelengths around 1320 nm would be advantageous for deep harmless sensing and diagnostics of tissues

  18. Media activism as movement?: collective identity formation in the World Forum of Free Media

    OpenAIRE

    Stephansen, Hilde C.

    2017-01-01

    More than simply tools used by social movements to reach other substantive aims, media are increasingly becoming subjects of activism. This article contributes to advancing understanding of such media-focused activism through a case study of the World Forum of Free Media, a thematic forum for media activists and media advocacy organisations linked to the World Social Forum. Based on qualitative research conducted between 2008 and 2016 -including participant observation, in-depth interviews an...

  19. Laser based analysis using a passively Q-switched laser employing analysis electronics and a means for detecting atomic optical emission of the laser media

    Science.gov (United States)

    Woodruff, Steven D.; Mcintyre, Dustin L.

    2016-03-29

    A device for Laser based Analysis using a Passively Q-Switched Laser comprising an optical pumping source optically connected to a laser media. The laser media and a Q-switch are positioned between and optically connected to a high reflectivity mirror (HR) and an output coupler (OC) along an optical axis. The output coupler (OC) is optically connected to the output lens along the optical axis. A means for detecting atomic optical emission comprises a filter and a light detector. The optical filter is optically connected to the laser media and the optical detector. A control system is connected to the optical detector and the analysis electronics. The analysis electronics are optically connected to the output lens. The detection of the large scale laser output production triggers the control system to initiate the precise timing and data collection from the detector and analysis.

  20. Self-transparency effects in heterogeneous nonlinear scattering media and their possible use in lasers

    International Nuclear Information System (INIS)

    Al'tshuler, G.B.; Ermolaev, V.S.; Krylov, K.I.; Manenkov, A.A.; Prokhorov, A.M.

    1986-01-01

    Transmission of intense laser beams through heterogeneous scattering media is considered. Effects of intensity limitation, self-recovery of the wave front of a transmitted beam, and bistable reflection associated with the laser-induced self-transparency (suppression of scattering) of such media are predicted because of the compensation of the linear refractive-index difference Δn/sub L/ of the heterocomponents of a medium by nonlinear change Δn/sub N//sub L/ for different mechanisms of nonlinearity. Applications of these effects in lasers for Q switching and mode locking are discussed. The observation of self-transparency effects in several heterogeneous media (glass particles in toluene and nitrobenzene, and lead molybdenite powder) for cw Ar- and pulsed Nd- and CO 2 -laser radiation is reported. Q switching and mode locking have also been demonstrated with a YAG:Nd laser using nonlinear scattering in a heterogeneous cell as a control element in a laser resonator

  1. Pulsed Laser Deposition: passive and active waveguides

    Czech Academy of Sciences Publication Activity Database

    Jelínek, Miroslav; Flory, F.; Escoubas, L.

    2009-01-01

    Roč. 34, č. 4 (2009), s. 438-449 ISSN 0268-1900 R&D Projects: GA ČR GA202/06/0216 Institutional research plan: CEZ:AV0Z10100522 Keywords : PLD * pulsed laser deposition * laser ablation * passive waveguides * active waveguides * waveguide laser * sensors * thin films * butane detection Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.384, year: 2009

  2. Electroweak processes in external active media

    CERN Document Server

    Kuznetsov, Alexander

    2013-01-01

    Expanding on the concept of the authors’ previous book “Electroweak Processes in External Electromagnetic Fields,” this new book systematically describes the investigation methods for the effects of external active media, both strong electromagnetic fields and hot dense plasma, in quantum processes. Solving the solar neutrino puzzle in a unique experiment conducted with the help of the heavy-water detector at the Sudbery Neutrino Observatory, along with another neutrino experiments, brings to the fore electroweak physics in an active external medium. It is effectively demonstrated that processes of neutrino interactions with active media of astrophysical objects may lead, under some physical conditions, to such interesting effects as neutrino-driven shockwave revival in a supernova explosion, a “cherry stone shooting” mechanism for pulsar natal kick, and a neutrino pulsar. It is also shown how poor estimates of particle dispersion in external active media sometimes lead to confusion. The book...

  3. The New Digital Media Value Network: Proposing an Interactive Model of Digital Media Value Activities

    Directory of Open Access Journals (Sweden)

    Sylvia Chan-Olmsted

    2016-07-01

    Full Text Available This study models the dynamic nature of today’s media markets using the framework of value-adding activities in the provision and consumption of media products. The proposed user-centric approach introduces the notion that the actions of external users, social media, and interfaces affect the internal value activities of media firms via a feedback loop, and therefore should themselves be considered value activities. The model also suggests a more comprehensive list of indicators for value assessment.

  4. Media Literacy Art Education: Logos, Culture Jamming, and Activism

    Science.gov (United States)

    Chung, Sheng Kuan; Kirby, Michael S.

    2009-01-01

    Critical media literacy art education teaches students to: (1) appreciate the aesthetic qualities of media; (2) critically negotiate meanings and analyze media culture as products of social struggle; and (3) use media technologies as instruments of creative expression and social activism. In concert with art education practices oriented toward…

  5. Field-Testing of an Active Laser Tracking System

    Science.gov (United States)

    Markov, V.; Khiznyak, A.; Woll, D.; Liu, S.

    Comprehensive space surveillance demands a more accurate technique in tracking multi-dimensional state vector (3D coordinate, velocity, vibration, etc.) of the space objects. RF radiometric techniques typically can not provide the needed accuracy, while passive optical (and laser) tracking systems can provide distance to the object and its angular position, but not a direct reading of velocity, the parameter of primary importance for space object tracking and characterization. Addressing this problem with active optical tracking techniques is challenging because of the great distances involved, the high velocity of the satellites, and the optical aberrations induced by the atmosphere. We have proposed a phase conjugation based laser tracking concept, and accomplished the first version of design and engineering of a prototype for an Active Laser Tracking System (ALTS). In its current state the ALTS is capable to demonstrate the very basics operational principles of the proposed active tracking technique. We then performed a number of experiments to prove operational capabilities of this prototype both at MetroLaser's lab environment and at Edwards AFB Test Range. In its current architecture the ALTS is comprised of two laser cavities, Master and Slave that are coupled through a Phase Conjugate Mirror (PCM) formed in a non-linear medium (NLM) set at Master laser cavity. By pumping NLM and forming PCM, Master laser establishes the cavities coupling mode and injects the photons in the slave cavity. It is essential that the specific features of the PCM not only serve to couple ALTS cavities, but also serves to compensate optical aberrations of the ALTS (gain media and optical elements of the laser resonator). Due to its ability to compensate optical aberrations, phase conjugate resonators are capable of sustaining oscillation with a remote target as an output coupler. The entire system comprises of several modules, including a laser, emitting/receiving telescope, gimbal

  6. BaY2F8 single crystals doped with rare-earth ions as promising up-conversion media for UV and VUV lasers

    International Nuclear Information System (INIS)

    Pushkar', A A; Uvarova, T V; Molchanov, V N

    2008-01-01

    BaY 2 F 8 crystals are studied as promising active media for UV and VUV lasers. The up-conversion pumping of rare-earth activators is proposed to solve problems related to the solarisation of the medium and the selection of pump sources. The technology of growing oriented BaY 2 F 8 single crystals is developed and the influence of the crystal orientation on the growth rate and quality of single crystals is determined. (active media)

  7. Laser Beam Propagation Through Inhomogeneous Media with Shock-Like Profiles: Modeling and Computing

    Science.gov (United States)

    Adamovsky, Grigory; Ida, Nathan

    1997-01-01

    Wave propagation in inhomogeneous media has been studied for such diverse applications as propagation of radiowaves in atmosphere, light propagation through thin films and in inhomogeneous waveguides, flow visualization, and others. In recent years an increased interest has been developed in wave propagation through shocks in supersonic flows. Results of experiments conducted in the past few years has shown such interesting phenomena as a laser beam splitting and spreading. The paper describes a model constructed to propagate a laser beam through shock-like inhomogeneous media. Numerical techniques are presented to compute the beam through such media. The results of computation are presented, discussed, and compared with experimental data.

  8. Effectiveness of Corporate Social Media Activities to Increase Relational Outcomes

    DEFF Research Database (Denmark)

    Risius, Marten; Beck, Roman

    2015-01-01

    This study applies social media analytics to investigate the impact of different corporate social media activities on user word of mouth and attitudinal loyalty. We conduct a multilevel analysis of approximately 5 million tweets regarding the main Twitter accounts of 28 large global companies. We...... empirically identify different social media activities in terms of social media management strategies (using social media management tools or the web-frontend client), account types (broadcasting or receiving information), and communicative approaches (conversational or disseminative). We find positive...... effects of social media management tools, broadcasting accounts, and conversational communication on public perception....

  9. Superluminous laser pulse in an active medium

    International Nuclear Information System (INIS)

    Fisher, D.L.; Tajima, T.

    1993-12-01

    Physical conditions are obtained to make the propagation velocity of a laser pulse and thus the phase velocity of the excited wake be at any desired value, including that equal to or greater than the speed of light. The provision of an active-plasma laser medium with an appropriately shaped pulse allows not only replenishment of laser energy loss to the wakefield but also acceleration of the group velocity of photons. A stationary solitary solution in the accelerated frame is obtained from the model equations and simulations thereof for the laser, plasma and atoms. This approach has applications in photonics and telecommunications as well as wakefield accelerators

  10. A laser activated ion source

    International Nuclear Information System (INIS)

    Hughes, J.; Luther-Davies, B.; Hora, H.; Kelly, J.

    1978-01-01

    Apparatus for generating energetic ions of a target material from a cold plasma of the material is described. A pulsed laser beam is directed onto the target to produce the cold plasma. Laser beam pulses are short in relation to the collision time in the plasma. Non-linear elctrodynamic forces within the plasma act to accelerate and eject ions from the plasma. The apparatus can be used to separate ions of isotopes of an element

  11. Social Media Activism and State Censorship

    NARCIS (Netherlands)

    Poell, T.; Trottier, D.; Fuchs, C.

    2015-01-01

    This chapter interrogates how activist social media communication in authoritarian contexts is shaped through the mutual articulation of social media user practices, business models, and technological architectures, as well as through the controlling efforts of states. It specifically focuses on

  12. Uranium Institute information activities and the media

    International Nuclear Information System (INIS)

    Maden, Claire

    1995-01-01

    The Uranium Institute is the international organisation for energy from nuclear fuel. Its membership is made up of companies from all over the world and all facets of the civil nuclear industry. The Ul Information Service is based very much on the Ul library in London. Enquiries can - and do - come from any interested party, from an 8-year old wanting information on the nuclear industry for a school project, to a request for technical data from a member company. We can provide all kinds of information on the nuclear energy and uranium industries, and on related topics ranging from energy and electricity supply to relevant environmental issues. The media forms a major Information Service user group, even though the Information Service is not a press office. Why does the press come to us? We think there are a number of reasons. Firstly, we are able to provide quick responses when necessary, but we can also give in depth responses and provide background information. Secondly, although we are perceived as a pro-nuclear organisation, we are also seen to have a certain distance from individual companies in the industry. Thirdly, the Ul Information Service works closely with Ul Research Officers and has access to the expertise of its members, making a worldwide information network. Their support and assistance provide informed comment and back up. Media contact through the Information Service is an effective way for a small operation like the Ul to achieve a positive impact on behalf of the nuclear industry. We may not actually be responsible for what gets printed in the papers or said on television, but we can at least do our best to ensure that those who are responsible are well informed, and give the nuclear industry fair coverage. We see our activities with the media as a long-term investment. As journalists become better informed on the nuclear industry, we hope that they will develop a healthy scepticism when faced with sensational nuclear horror stories, and base

  13. Active Social Media Management: The Case of Health Care

    OpenAIRE

    Miller, Amalia R.; Tucker, Catherine Elizabeth

    2012-01-01

    Given the demand for authentic personal interactions over social media, it is unclear how much firms should actively manage their social media presence. We study this question empirically in a health care setting. We show that active social media management drives more user-generated content. However, we find that this is due to an incremental increase in user postings from an organization's employees rather than from its clients. This result holds when we explore exogenous variation in socia...

  14. Effects of laser fluence and liquid media on preparation of small Ag nanoparticles by laser ablation in liquid

    Science.gov (United States)

    Moura, Caroline Gomes; Pereira, Rafael Santiago Floriani; Andritschky, Martin; Lopes, Augusto Luís Barros; Grilo, João Paulo de Freitas; Nascimento, Rubens Maribondo do; Silva, Filipe Samuel

    2017-12-01

    This study aims to assess a method for preparation of small and highly stable Ag nanoparticles by nanosecond laser ablation in liquid. Effect of liquid medium and laser fluence on the size, morphology and structure of produced nanoparticles has been studied experimentally. Pulses of a Nd:YAG laser of 1064 nm wavelength at 35 ns pulse width at different fluences were employed to irradiate the silver target in different environments (water, ethanol and acetone). The UV-Visible absorption spectra of nanoparticles exhibit surface plasmon resonance absorption peak in the UV region. STEM and TEM micrographs were used to evaluate the size and shape of nanoparticles. The stability of silver colloids in terms of oxidation at different liquid media was analyzed by SAED patterns. The results showed that characteristics of Ag nanoparticles and their production rate were strongly influenced by varying laser fluence and liquid medium. Particles from 2 to 80 nm of diameter were produced using different conditions and no oxidation was found in ethanol and acetone media. This work puts in evidence a promising approach to produce small nanoparticles by using high laser fluence energy.

  15. Self-reconstruction of diffraction-free and accelerating laser beams in scattering media

    International Nuclear Information System (INIS)

    Ersoy, T.; Yalizay, B.; Akturk, S.

    2012-01-01

    We experimentally investigate propagation of laser beams with different intensity profiles in highly scattering media. We generate transverse laser amplitude profiles with Gaussian, Bessel and Airy function envelopes. We then propagate these beams through optical phantoms formed with variable density intralipid solutions. At the sample exit, we compare change in maximum intensities, as well as beam profile reconstruction. We show that self-reconstruction properties of Bessel and Airy beams bring about slower decrease in maximum intensity with increasing scatterer density. On the other hand, the beam profiles deteriorate faster, as compared to reference Gaussian beams. Slower decrease in the intensity can be attributed to the wavevector spectra providing a continuous flow of energy to the beam center, while beam deterioration is linked to total beam volume in the scattering medium. These results show that beam shaping methods can significantly enhance delivery of intense light deeper into turbid media, but this enhancement is compromised by stronger speckling of beam profiles. -- Highlights: ► We experimentally investigate propagation of shaped laser beams in turbid media. ► Peak intensity of Bessel and Airy beams decrease slower with increasing scatterer. ► Shaped beam profiles deteriorate faster, as compared to reference Gaussian beams. ► Shaped beam profiles can enhance applications of lasers inscattering media.

  16. Laser beam propagation in non-linearly absorbing media

    CSIR Research Space (South Africa)

    Forbes, A

    2006-08-01

    Full Text Available Many analytical techniques exist to explore the propagation of certain laser beams in free space, or in a linearly absorbing medium. When the medium is nonlinearly absorbing the propagation must be described by an iterative process using the well...

  17. Transparent media characterization using sub-pico second dye laser

    International Nuclear Information System (INIS)

    Lamy, F.; Fontaine, J.J.

    1982-01-01

    A new passively mode locked laser source developed at the Center for Laser Studies yielded pulses shorter than 0.14 ps, at a rate of 250 MHz or 0.3 ps pulses at a rate of 500 MHz. The laser and its modes of operation are described. With this source and a second order cross correlation technique similar to the autocorrelation used to determine the pulse duration, time domain reflectometry measurements can be made with a resolution of 40 μm. Three dimensional images can be made by time resolving the backscattered radiation of a beam scanned through a medium. The depth resolution of 0.1 μm can be carried over to the other two dimensions by computer reconstruction. The new technique should have important applications in medicine and biology. Because of the short duration of the laser pulses, high peak intensities can be used without damage to the tissues. Therefore, light measurements can be conducted through a larger depth than with continuous radiation. (orig.)

  18. Connecting Corporate and Consumer Social Responsibility Through Social Media Activism

    DEFF Research Database (Denmark)

    Kampf, Constance Elizabeth

    2018-01-01

    To highlight aspects of activism obscured by a focus on legitimacy and ideology, this paper argues that shifting focus from legitimacy and ideology to identity, problem-solving & dialogue is needed to understand emerging forms of Social Media Native Activism that connect Consumer Social Responsib......To highlight aspects of activism obscured by a focus on legitimacy and ideology, this paper argues that shifting focus from legitimacy and ideology to identity, problem-solving & dialogue is needed to understand emerging forms of Social Media Native Activism that connect Consumer Social...... Responsibility (CnSR) and Corporate Social Responsibility (CSR). Taking this view as a basis for social activism offers a valuable perspective for understanding some emergent forms of social media activism towards business. Two cases of social media ‘native’ social activist organizations working to create...

  19. Activation volume and interaction of metal particulate media

    Energy Technology Data Exchange (ETDEWEB)

    Tetsukawa, Hiroki [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)]. E-mail: tetsukaw@arc.sony.co.jp; Kondo, Hirofumi [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)

    2005-09-15

    We have investigated the activation volume (V{sub ac}) and magnetostatic interaction of metal particulate (MP) media. The activation volume of MP media decreases with the decrease of physical volume (V{sub phy}) of metal particles. The activation volume and the ratio of V{sub phy}/V{sub ac} of advanced metal particles are 6x10{sup -24}m{sup 3} and 1.5, respectively. It can be predicted that the physical volume of metal particle is about 3x10{sup -24}m{sup 3} when the physical volume is equal to the activation volume. This value is agreement with the practical lower limit of physical volume of metal particle predicted by Sharrock. The negative interaction (demagnetization effect) in MP media decreases with low saturation magnetization of the metal particles, a thin magnetic layer, a high orientation of MP media, and a low packing fraction of metal particles in the MP media. The activation volume of the MP media decreased as the negative interactions decreased. In advanced MP media with low M{sub r}.t (M{sub r}=remanent magnetization and t=thickness), the influence of interaction on the activation volume is reduced.

  20. Activation volume and interaction of metal particulate media

    International Nuclear Information System (INIS)

    Tetsukawa, Hiroki; Kondo, Hirofumi

    2005-01-01

    We have investigated the activation volume (V ac ) and magnetostatic interaction of metal particulate (MP) media. The activation volume of MP media decreases with the decrease of physical volume (V phy ) of metal particles. The activation volume and the ratio of V phy /V ac of advanced metal particles are 6x10 -24 m 3 and 1.5, respectively. It can be predicted that the physical volume of metal particle is about 3x10 -24 m 3 when the physical volume is equal to the activation volume. This value is agreement with the practical lower limit of physical volume of metal particle predicted by Sharrock. The negative interaction (demagnetization effect) in MP media decreases with low saturation magnetization of the metal particles, a thin magnetic layer, a high orientation of MP media, and a low packing fraction of metal particles in the MP media. The activation volume of the MP media decreased as the negative interactions decreased. In advanced MP media with low M r .t (M r =remanent magnetization and t=thickness), the influence of interaction on the activation volume is reduced

  1. Connecting Corporate and Consumer Social Responsibility Through Social Media Activism

    DEFF Research Database (Denmark)

    Kampf, Constance Elizabeth

    2018-01-01

    To highlight aspects of activism obscured by a focus on legitimacy and ideology, this paper argues that shifting focus from legitimacy and ideology to identity, problem-solving & dialogue is needed to understand emerging forms of Social Media Native Activism that connect Consumer Social...... Responsibility (CnSR) and Corporate Social Responsibility (CSR). Taking this view as a basis for social activism offers a valuable perspective for understanding some emergent forms of social media activism towards business. Two cases of social media ‘native’ social activist organizations working to create...... movements are examined from this problem solving & dialogue-based perspective—Carrotmob, and the Good Guide. These cases represent examples of a post-dialectic frame for understanding how social media can affect approaches to activism....

  2. Transmission media appropriate laser-microwave solar power satellite system

    Science.gov (United States)

    Schäfer, C. A.; Gray, D.

    2012-10-01

    As a solution to the most critical problems with Solar power Satellite (SPS) development, a system is proposed which uses laser power transmission in space to a receiver high in the atmosphere that relays the power to Earth by either cable or microwave power transmission. It has been shown in the past that such hybrid systems have the advantages of a reduction in the mass of equipment required in geostationary orbit and avoidance of radio frequency interference with other satellites and terrestrial communications systems. The advantage over a purely laser power beam SPS is that atmospheric absorption is avoided and outages due to clouds and precipitation will not occur, allowing for deployment in the equatorial zone and guaranteeing year round operation. This proposal is supported by brief literature surveys and theoretical calculations to estimate crucial parameters in this paper. In relation to this concept, we build on a recently proposed method to collect solar energy by a tethered balloon at high altitude because it enables a low-cost start for bringing the first Watt of power to Earth giving some quick return on investment, which is desperately missing in the traditional SPS concept. To tackle the significant problem of GW-class SPSs of high launch cost per kg mass brought to space, this paper introduces a concept which aims to achieve a superior power over mass ratio compared to traditional satellite designs by the use of thin-film solar cells combined with optical fibres for power delivery. To minimise the aperture sizes and cost of the transmitting and receiving components of the satellite and high altitude receiver, closed-loop laser beam pointing and target tracking is crucial for pointing a laser beam onto a target area that is of similar size to the beam's diameter. A recently developed technique based on optical phase conjugation is introduced and its applicability for maintaining power transmission between the satellite and high altitude receiver is

  3. Verification of a characterization method of the laser-induced selective activation based on industrial lasers

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; Tang, Peter T.

    2013-01-01

    In this article, laser-induced selective activation (LISA) for subsequent autocatalytic copper plating is performed by several types of industrial scale lasers, including a Nd:YAG laser, a UV laser, a fiber laser, a green laser, and a short pulsed laser. Based on analysis of all the laser......-machined surfaces, normalized bearing area curves and parameters are used to characterize the surface quantitatively. The range of normalized bearing area curve parameters for plate-able surface is suggested. PBT/PET with 40 % glass fiber was used as the substrate material. For all of the studied lasers......, the parameters were varied in a relatively large range, and matrixes of the laser-machined surface were obtained. The topography of those laser-machined surfaces was examined by scanning electronic microscope (SEM). For each sample examined by SEM, there was an identical workpiece plated by for 90 min...

  4. Analysis of Information Leakages on Laser Printers in the Media of Electromagnetic Radiation and Line Conductions

    OpenAIRE

    Ulaş, Cihan

    2016-01-01

    In this paper, the emissions of a laser printer, which may process classified information, are investigated in the media of electromagnetic radiation (ER), Power Line Conductors (PLC), and Signal Line Conductors (SLC). First, the candidate frequency points of CE are examined in the frequency domain. Second, the emitted signal is AM-demodulated with the proper bandwidth, and then sampled by a high storage oscilloscope in these frequency points. Third, the collected data is converted to 2D imag...

  5. Thermal wave propagation in the pulsed laser irradiation of media with thermal memory

    International Nuclear Information System (INIS)

    Galovic, S.; Kostoski, D.; Stamboliev, G.; Suljovrujic, E.

    2002-01-01

    Complete text of publication follows. If a sample is exposed to the influence of laser radiation part of its energy is absorbed and converted in heat. The heat generated in this way is transferred through the sample as heat waves, resulting in various effects (so called photothermal effects). A large number of nondestructive diagnostic methods are based on recording of these effects. It is necessary to create a good model in order to understand and correctly describe the measured results of heat transfer in different media. In a certain number of materials and structures, such as complex biological materials, polymers, metals excited by very short laser pulses etc., the property of thermal memory has been experimentally observed. Starting with the hyperbolic equation that describes heat transfer processes of such media, in this paper has been developed a model of laser-excited heat waves propagation in order to enable application of photothermal techniques in characterization of these media. The cases of optically opaque and transparent samples are considered. The influence of various backings on photothermal waves has also been analyzed. The results are compared to the previous models

  6. The effect of laser treatment on the wear resistance of steel in corrosive media

    International Nuclear Information System (INIS)

    Plyatsko, G.V.; Porter, A.I.; Prejs, G.A.; Mojsa, M.I.

    1975-01-01

    The corrosion mechanical wearing properties of steel 45 treated with a laser beam (H 100 =7800 Mn/sq.m) under friction with nitrated steel 40KhNMA (HV=7000 Mn/sq.m), chrome cast iron Kh15M (hardened and low-temperature tempered, modified), perlite cast iron and bronze are studied. The aqueous buffers with pH=6 and 11 are used as a corrosion active media. In a weakly acid medium the most intensive wearing of steel 40KhNMA is observed at P=8 Mn/sq.m. Its wearing reduces due to increase of pressure to 12 Mn/sq.m. Extent of steel 45 wearing increases with pressure increase from 8 to 12 Mn/sg.m. Friction coefficient of this pair changes by jumps at an increase of normal pressure and its variation range is smaller than that observed in an alkaline medium. The maximum value of friction coefficient is shifted to the higher pressure. The wearing of cast iron Kh15M-steel 45 pair has an alternative pattern. In an alkaline medium the cast iron wearing intensity shows a linear increase with the normal contact pressure but that of the steel changes jumpwise attaining extreme at 8 and 12 Mn/sq.m. In a weak acid medium the intensity of grasping and graphitization at the friction surface of cast iron Kh15M-steel 45 pair is higher than that in the alkaline medium. Experiments demonstrate an effectiveness of the laser beam treatment of steel 45 for its friction in the alkaline medium with nitrated steel 40KhNMA and with hardened low-temperature tempered cast iron 45 under friction contact pressure as high as 8 Mn/sq.m, and in acid medium at 12 and 8 Mn/sq.m respectively. The laser treatment provides high corrosion-mechanical stability of steel 45 and the counterbodies described, as well as the low friction coefficient of these pairs

  7. Mechanism of laser ablation for aqueous media irradiated under confined-stress conditions

    International Nuclear Information System (INIS)

    Oraevsky, A.A.; Jacques, S.L.; Tittel, F.K.

    1995-01-01

    Pulsed laser ablation of aqueous medium irradiated under conditions of temporal confinement of thermal stress is described. Time-resolved measurements of laser-induced transient stress waves with simultaneous imaging of ablation process by laser-flash photography were performed. Stress transients induced in aqueous solution of K 2 CrO 4 by ablative nanosecond laser pulses at 355 nm were studied by a broad-band lithium niobate acoustic transducer. Recoil momentum upon material ejection was measured from the temporal profiles of the acoustic transducer signal as a function of incident laser fluence. Cavitation bubbles produced in the irradiated volume during the tensile phase of thermoelastic stress were shown to drive material ejection at temperatures substantially below 100 degree C. Experimental data are evident that nanosecond-pulse laser ablation of aqueous media (when temporal stress-confinement conditions are satisfied) include the following two main stages of material ejection: (1) ejection of water microdroplets due to expansion and rupture of subsurface cavitation bubbles; (2) ejection of liquid streams with substantial volume upon collapse of initial crater and large cavitation bubbles in the depth of irradiated volume (after coalescence of smaller bubbles). copyright 1995 American Institute of Physics

  8. LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Modification of biological objects in water media by CO2-laser radiation

    Science.gov (United States)

    Baranov, G. A.; Belyaev, A. A.; Onikienko, S. B.; Smirnov, S. A.; Khukharev, V. V.

    2005-09-01

    The modification of biological objects (polysaccharides and cells) by CO2-laser radiation in water added drop by drop into the interaction region is studied theoretically and experimentally. Calculations are performed by using the models describing gas-dynamic and heterogeneous processes caused by absorption of laser radiation by water drops. It is found experimentally that the laser modification of polysaccharides leads to the formation of low-molecular derivatives with immunostimulating properties. A dose of the product of laser activation of the yeast culture Saccharamyces cerevisiae prevented the development of a toxic emphysema in mice and protected them against lethal grippe and also prevented a decrease of survival rate, increased the average life, and prevented the development of metabolic and immune disorders in mice exposed to sublethal gamma-radiation doses.

  9. They Are What You Hear in Media Reports: The Racial Stereotypes toward Uyghurs Activated by Media

    Science.gov (United States)

    Jin, Jia; Pei, Guanxiong; Ma, Qingguo

    2017-01-01

    Stereotypes from the major nationality toward minorities constitute a widely concerning problem in many countries. As reported by previous studies, stereotypes can be activated by media information that portrays the negative aspects of the target group. The current study focused on the neural basis of the modulation of negative media information on Han Chinese stereotypes toward Uyghurs by using event-related potentials. We employed the lexical decision task, in which participants were asked to categorize the presented word as positive or negative. Behavioral result showed that participants had a shorter reaction time to positive adjectives than to negative adjectives. The data of brain activity showed that compared with the Han condition, the Uyghurs condition elicited smaller N400 differences in the media priming group, whereas there was no significant N400 deflection difference between Han Chinese and Uyghurs in the control group. The current results suggested that the negative media information might influence their judgments toward other groups reflected in the deflection of N400 amplitude. Therefore, in order to mitigate or even eliminate stereotypes about national minorities, the effort of the media is important. PMID:29270104

  10. They Are What You Hear in Media Reports: The Racial Stereotypes toward Uyghurs Activated by Media.

    Science.gov (United States)

    Jin, Jia; Pei, Guanxiong; Ma, Qingguo

    2017-01-01

    Stereotypes from the major nationality toward minorities constitute a widely concerning problem in many countries. As reported by previous studies, stereotypes can be activated by media information that portrays the negative aspects of the target group. The current study focused on the neural basis of the modulation of negative media information on Han Chinese stereotypes toward Uyghurs by using event-related potentials. We employed the lexical decision task, in which participants were asked to categorize the presented word as positive or negative. Behavioral result showed that participants had a shorter reaction time to positive adjectives than to negative adjectives. The data of brain activity showed that compared with the Han condition, the Uyghurs condition elicited smaller N400 differences in the media priming group, whereas there was no significant N400 deflection difference between Han Chinese and Uyghurs in the control group. The current results suggested that the negative media information might influence their judgments toward other groups reflected in the deflection of N400 amplitude. Therefore, in order to mitigate or even eliminate stereotypes about national minorities, the effort of the media is important.

  11. They Are What You Hear in Media Reports: The Racial Stereotypes toward Uyghurs Activated by Media

    Directory of Open Access Journals (Sweden)

    Jia Jin

    2017-12-01

    Full Text Available Stereotypes from the major nationality toward minorities constitute a widely concerning problem in many countries. As reported by previous studies, stereotypes can be activated by media information that portrays the negative aspects of the target group. The current study focused on the neural basis of the modulation of negative media information on Han Chinese stereotypes toward Uyghurs by using event-related potentials. We employed the lexical decision task, in which participants were asked to categorize the presented word as positive or negative. Behavioral result showed that participants had a shorter reaction time to positive adjectives than to negative adjectives. The data of brain activity showed that compared with the Han condition, the Uyghurs condition elicited smaller N400 differences in the media priming group, whereas there was no significant N400 deflection difference between Han Chinese and Uyghurs in the control group. The current results suggested that the negative media information might influence their judgments toward other groups reflected in the deflection of N400 amplitude. Therefore, in order to mitigate or even eliminate stereotypes about national minorities, the effort of the media is important.

  12. Activism or "Slacktivism?": Digital Media and Organizing for Social Change

    Science.gov (United States)

    Glenn, Cerise L.

    2015-01-01

    The influence of social media and technological developments has changed how groups and organizations advocating for social change generate awareness and participation in their causes. In this single class activity students will (a) analyze notions of activism and "slacktivism" from scholarly and popular sources to apply these concepts…

  13. Physical Activity in the Mass Media: An Audience Perspective

    Science.gov (United States)

    Smith, Ben J.; Bonfiglioli, Catriona M. F.

    2015-01-01

    Physical activity's role in promoting health is highlighted in public health campaigns, news and current affairs, reality television and other programs. An investigation of audience exposure, beliefs and reactions to media portrayals of physical activity offers insights into the salience and influence of this communication. An audience reception…

  14. Media Framing of Third Sector Activities in Europe

    DEFF Research Database (Denmark)

    Lund, Anker Brink; Lilleør, Anton Sylvest

    innovation framed by European news media? The analysis is one part of the deliverable D2.3 ‘Images of the Third Sector’ of the ITSSOIN project. D2.3 has been conceptualised to evaluate perceptions of media and citizens attitudes towards the third sector. Both perspectives are published as distinct...... and independent papers. Readers also interested in the citizen perception find more insights in the publication ‘Empirical analyses of citizen perceptions of the third sector in Europe’. The introduction (section 1) demonstrates that little relevant media research has been published specifically on third sector...... of this kind. The media content analysis (section 2) summarizes the major trends in mediated discourse on third sector activities in the Czech Republic, Denmark, France, Germany, Italy, the Netherlands, Spain, Sweden and the United Kingdom 2003-2013. These tendencies are related to social innovation policy...

  15. Transport of biologically active material in laser cutting.

    Science.gov (United States)

    Frenz, M; Mathezloic, F; Stoffel, M H; Zweig, A D; Romano, V; Weber, H P

    1988-01-01

    The transport of biologically active material during laser cutting with CO2 and Er lasers is demonstrated. This transport mechanism removes particles from the surface of gelatin, agar, and liver samples into the depth of the laser-formed craters. The transport phenomenon is explained by a contraction and condensation of enclosed hot water vapor. We show by cultivating transported bacteria in agar that biological particles can survive the shock of the transport. Determination of the numbers of active cells evidences a more pronounced activity of the cultivated bacteria after impact with an Er laser than with a CO2 laser.

  16. Stability of iodinated contrast media in UV-laser irradiation and toxicity of photoproducts

    International Nuclear Information System (INIS)

    Groenewaeller, E.F.; Kehlbach, R.; Claussen, C.D.; Duda, S.H.; Wahl, H.G.; Rodemann, H.P.

    1998-01-01

    Purpose: In XeCl-Excimer laser angioplasty, unintended and possibly harmful interaction of the UV-laser light and the contrast media may occur due to the high concentration of contrast medium proximal to the occlusion or subtotal stenosis. Methods: One ml of three nonionic monomeric contrast agents (iopromide, iomeprol, iopamidol), one nonionic dimetric (jotrolane), and one ionic monomeric (amidotrizoate) X-ray contrast agent were irradiated with a XeCl excimer laser (λ=308 nm, pulse duration 120 ns, 50 Hz) using a 9 French multifiber catheter (12 sectors). Up to 20 000 pulses (106 J) were applied. Using high performance liquid chromatography the amount of liberated iodide as well as the fraction of unchanged contrast media were measured. Cytotoxicity of the photoproducts was tested in a colony formation assay of human skin fibroblasts. The contrast agents were irradiated with 2000 pulses/ml (5.3 mJ/pulse; 10.6 J) and then added to the cell cultures for a period of three hours in a concentration of 10%. Results: Excimer laser irradiation induced iodide liberation of up to 3.3 mg iodide/ml. Up to 19% of the contrast agents changed their original molecular structure. Incubation of irradiated contrast agents resulted in a significantly decreased potential for colony formation (p values ranging from 0.0044 to 0.0102) with significantly higher toxicity of amidotrizoate and iomeprol in comparison to iopromide, iotrolan, and iopamidol. Discussion: Due to the cytotoxic photoproducts and the high level of liberated iodide, it is recommended to flush the artery with physiological saline solution before applying a pulsed excimer laser in human arterial obstructions in order to reduce the contrast agent concentration at the site of irradiation. (orig.) [de

  17. Color centers inside crystallic active media

    Science.gov (United States)

    Mierczyk, Zygmunt; Kaczmarek, Slawomir M.; Kopczynski, Krzysztof

    1995-03-01

    This paper presents research results on color centers induced by radiation of a xenon lamp in non doped crystals of yttrium aluminum garnet Y3Al5O12 (YAG), strontium- lanthanum aluminate SrLaAlO4 (SLAO), strontium-lanthanum gallate SrLaGa3O7 (SLGO), and in doped crystals: Nd:YAG, Cr, Tm, Ho:YAG (CTH:YAG), Nd:SLAO and Nd:SLGO. In all these investigated crystals under the influence of intensive exposure by xenon lamp radiation additional bands connected with centers O-2, O2 and centers F came up near the short-wave absorption edge. In the case of doped crystals the observed processes are much more complicated. In crystals CTH:YAG the greatest perturbations in relation to basic state are present at the short-wave absorption edge, as well as on areas of absorption bands of ions Cr+3 and Tm+3 conditioning the sensibilization process of ions Ho+3. These spectral structure disturbances essentially influence the efficiency of this process, as proven during generating investigations. In the case of SrLaGa3O7:Nd+3 under the influence of exposure substantial changes of absorption spectrum occurred on spectral areas 346 divided by 368 nm, 429 divided by 441 nm and 450 divided by 490 nm. Those changes have an irreversible character. They disappear not before the plate is being held at oxidizing atmosphere. Investigations of laser rods Nd:SLGO, CTH:YAG, and Nd:YAG in a free generation demonstrated that the color centers of these crystals are induced by pomp radiation from the spectral area up to 450 nm.

  18. Anticipating Activity in Social Media Spikes

    OpenAIRE

    Higham, Desmond J.; Grindrod, Peter; Mantzaris, Alexander V.; Otley, Amanda; Laflin, Peter

    2014-01-01

    We propose a novel mathematical model for the activity of microbloggers during an external, event-driven spike. The model leads to a testable prediction of who would become most active if a spike were to take place. This type of information is of great interest to commercial organisations, governments and charities, as it identifies key players who can be targeted with information in real time when the network is most receptive. The model takes account of the fact that dynamic interactions ev...

  19. Nonlinear interaction of charged particles with strong laser pulses in a gaseous media

    Directory of Open Access Journals (Sweden)

    H. K. Avetissian

    2007-07-01

    Full Text Available The charged particles nonlinear dynamics in the field of a strong electromagnetic wave pulse of finite duration and certain form of the envelope, in the refractive medium with a constant and variable refraction indexes, is investigated by means of numerical integration of the classical relativistic equations of motion. The particle energy dependence on the pulse intensity manifests the nonlinear threshold phenomenon of a particle reflection and capture by actual laser pulses in dielectric-gaseous media that takes place for a plane electromagnetic wave in the induced Cherenkov process. Laser acceleration of the particles in the result of the reflection from the pulse envelope and in the capture regime with the variable refraction index along the pulse propagation direction is investigated.

  20. Scanning laser techniques for dynamic thermo-magnetic recording onto stationary media

    Energy Technology Data Exchange (ETDEWEB)

    Clegg, Warwick; Jenkins, David; Helian, Na; Windmill, James; Windmill, Robert; Atkinson, Ron; Hendren, Bill; Wright, C. David

    2002-09-01

    Scanning laser microscopes (SLMs) have been used to characterise the magnetic properties of materials for some time (J. Magn. Magn. Mater. 95(1) (1991); IEEE Trans. Magn. 31(6 Pt. 1) (1995)). An SLM has been designed to facilitate a number of operating modes: both for writing and reading magneto-optical data. The current SLM is capable of thermo-magnetically recording bits onto magneto-optical thin films. Unlike previous SLMs, the current instrument has been designed to write bits both statically and dynamically onto stationary media. It will be used to write to magneto-optic (MO) disk material thermo-magnetically prior to imaging. Images may be derived from the longitudinal and polar magneto-optic Kerr effects, which are wavelength dependent, using the appropriate laser wavelength. In this paper the two configurations for dynamic recording are described.

  1. Scanning laser techniques for dynamic thermo-magnetic recording onto stationary media

    International Nuclear Information System (INIS)

    Clegg, Warwick; Jenkins, David; Helian, Na; Windmill, James; Windmill, Robert; Atkinson, Ron; Hendren, Bill; Wright, C. David

    2002-01-01

    Scanning laser microscopes (SLMs) have been used to characterise the magnetic properties of materials for some time (J. Magn. Magn. Mater. 95(1) (1991); IEEE Trans. Magn. 31(6 Pt. 1) (1995)). An SLM has been designed to facilitate a number of operating modes: both for writing and reading magneto-optical data. The current SLM is capable of thermo-magnetically recording bits onto magneto-optical thin films. Unlike previous SLMs, the current instrument has been designed to write bits both statically and dynamically onto stationary media. It will be used to write to magneto-optic (MO) disk material thermo-magnetically prior to imaging. Images may be derived from the longitudinal and polar magneto-optic Kerr effects, which are wavelength dependent, using the appropriate laser wavelength. In this paper the two configurations for dynamic recording are described

  2. Modelling of the energy density deposition profiles of ultrashort laser pulses focused in optical media

    International Nuclear Information System (INIS)

    Vidal, F; Lavertu, P-L; Bigaouette, N; Moore, F; Brunette, I; Giguere, D; Kieffer, J-C; Olivie, G; Ozaki, T

    2007-01-01

    The propagation of ultrashort laser pulses in dense optical media is investigated theoretically by solving numerically the nonlinear Schroedinger equation. It is shown that the maximum energy density deposition as a function of the pulse energy presents a well-defined threshold that increases with the pulse duration. As a consequence of plasma defocusing, the maximum energy density deposition is generally smaller and the size of the energy deposition zone is generally larger for shorter pulses. Nevertheless, significant values of the energy density deposition can be obtained near threshold, i.e., at lower energy than for longer pulses

  3. Laser-assisted molecular orientation in gaseous media: new possibilities and applications

    International Nuclear Information System (INIS)

    Zhdanov, Dmitry V; Zadkov, Victor N

    2009-01-01

    It was shown recently by us that an isotropic distribution of molecules in gaseous media can be drastically effected via their orientation-dependent selective excitation by a strong femtosecond multicomponent laser pulse. In the present paper, we analyze the specific effects accompanying the dynamical orientation of molecules driven this way. It is demonstrated that the peculiarities of the post-pulse transient angular distribution of molecules allow original proposals for the generation of pulsed terahertz radiation and also for the determination of the molecular rotational constants.

  4. Laser cutting of silicon with the liquid jet guided laser using a chlorine-containing jet media

    Energy Technology Data Exchange (ETDEWEB)

    Hopman, Sybille; Mayer, Kuno; Fell, Andreas; Mesec, Matthias; Granek, Filip [Fraunhofer Institute for Solar Energy Systems ISE, Freiburg (Germany)

    2011-03-15

    In this paper results for liquid media are presented, which are used the first time as liquid jet for cutting of silicon with laser chemical processing (LCP). The liquids contain a perfluoro-carbon compound as solvent and elemental chlorine as etching agent for silicon. Experiments were performed to investigate its influence on groove form and maximum achieved groove depth. It is shown that with the addition of low-concentration chlorine, the groove depth can already be significantly increased. The groove shape could be changed from a V-profile to a U-profile. Furthermore, an about four times greater groove depth was achieved by applying a saturated chlorine solution compared to groove depths without using chlorine. Finally, a theory is given and discussed to describe the phenomena observed. (orig.)

  5. Public Perception of Media Coverage of the Activities of the ...

    African Journals Online (AJOL)

    This study set out to investigate the awareness level, attention and attitude of the public towards media coverage of the activities of the Independent Corrupt Practices and other related offences Commission (ICPC). It also considered the appraisal of how the public select, organize and interpret stimuli about the commission.

  6. Rad Hard Active Media For Calorimeters

    CERN Document Server

    Norbeck, E; Möller, A; Onel, Y

    2006-01-01

    Zero-degree calorimeters have limited space and extreme levels of radiation. A simple, low cost, radiation hard design uses tungstenmetal as the absorber and a suitable liquid as the ˇCerenkov radiator. In other applications a PPAC (Parallel Plate Avalanche Counter) operatingwith a suitable atmosphericpressure gas is an attractive active material for a calorimeter. It can be made radiation hard and has sufficient gain in the gas that no electronic components are needed near the detector. It works well even with the highest concentration of shower particles. For this pressure range, R134A (used in auto air conditioners) has many desirable features.

  7. Optical storage media based on fluorite activated crystals

    International Nuclear Information System (INIS)

    Mokienko, I.Yu.; Poletimov, A.E.; Shcheulin, A.S.

    1991-01-01

    Earlier studied mechanisms of photo- and thermotransformations of defects in pure and activated additively coloured crystals with fluorite structure are considered to suggest several methods of reversible optical recording of images, characterized by high resistance to high-power laser radiation and mechanical deformation

  8. Consumer Health-Related Activities on Social Media: Exploratory Study.

    Science.gov (United States)

    Benetoli, Arcelio; Chen, Timothy F; Aslani, Parisa

    2017-10-13

    Although a number of studies have investigated how consumers use social media for health-related purposes, there is a paucity of studies in the Australian context. This study aimed to explore how Australian consumers used social media for health-related purposes, specifically how they identified social media platforms, which were used, and which health-related activities commonly took place. A total of 5 focus groups (n=36 participants), each lasting 60 to 90 minutes, were conducted in the Sydney metropolitan area. The group discussions were audiorecorded and transcribed verbatim. The transcripts were coded line-by-line and thematically analyzed. Participants used general search engines to locate health-related social media platforms. They accessed a wide range of social media on a daily basis, using several electronic devices (in particular, mobile phones). Although privacy was a concern, it did not prevent consumers from fully engaging in social media for health-related purposes. Blogs were used to learn from other people's experiences with the same condition. Facebook allowed consumers to follow health-related pages and to participate in disease-specific group discussions. Wikipedia was used for factual information about diseases and treatments. YouTube was accessed to learn about medical procedures such as surgery. No participant reported editing or contributing to Wikipedia or posting YouTube videos related to health topics. Twitter was rarely used for health-related purposes. Social media allowed consumers to obtain and provide disease and treatment-related information and social and emotional support for those living with the same condition. Most considered their participation as observational, but some also contributed (eg, responded to people's questions). Participants used a wide range of social media for health-related purposes. Medical information exchange (eg, disease and treatment) and social and emotional support were the cornerstones of their online

  9. Active-passively mode-locked dye laser for diagnosis of laser-produced plasmas

    International Nuclear Information System (INIS)

    Teng, Y.L.; Fedosejevs, R.; Sigel, R.

    1981-03-01

    In this report an active-passively mode-locked, flashlamp-pumped dye laser for diagnosis of laser-produced plasmas is described. This dye laser system used as a pulsed light source for high-speed photography of laser-target experiments was synchronized to the ASTERIX III iodine laser pulse with better than 100 ps accuracy. The single pulse energy was 10 μJ, pulse duration less than 10 ps. In 111 shots clear shadowgrams were obtained during a total of 151 target shots, i.e. the system worked well in 74% of the shots. (orig.)

  10. Rapid assessment of disaster damage using social media activity.

    Science.gov (United States)

    Kryvasheyeu, Yury; Chen, Haohui; Obradovich, Nick; Moro, Esteban; Van Hentenryck, Pascal; Fowler, James; Cebrian, Manuel

    2016-03-01

    Could social media data aid in disaster response and damage assessment? Countries face both an increasing frequency and an increasing intensity of natural disasters resulting from climate change. During such events, citizens turn to social media platforms for disaster-related communication and information. Social media improves situational awareness, facilitates dissemination of emergency information, enables early warning systems, and helps coordinate relief efforts. In addition, the spatiotemporal distribution of disaster-related messages helps with the real-time monitoring and assessment of the disaster itself. We present a multiscale analysis of Twitter activity before, during, and after Hurricane Sandy. We examine the online response of 50 metropolitan areas of the United States and find a strong relationship between proximity to Sandy's path and hurricane-related social media activity. We show that real and perceived threats, together with physical disaster effects, are directly observable through the intensity and composition of Twitter's message stream. We demonstrate that per-capita Twitter activity strongly correlates with the per-capita economic damage inflicted by the hurricane. We verify our findings for a wide range of disasters and suggest that massive online social networks can be used for rapid assessment of damage caused by a large-scale disaster.

  11. An in vitro antifungal efficacy of silver nanoparticles activated by diode laser to Candida albicans

    Science.gov (United States)

    Astuti, S. D.; Kharisma, D. H.; Kholimatussa'diah, S.; Zaidan, A. H.

    2017-09-01

    Microbial infectious diseases and increased resistance to antibiotics become urgent problems requiring immediate solutions. One promising alternative is the using of silver nanoparticles. The combination of the microbial inhibition characteristic of silver nanotechnology enhances the activity of antimicrobial effect. This study aims to determine effectiveness of antifungal silver nanoparticles with the activation of the diode laser on Candida albicans. The samples were culture of Candida albicans. Candida albicans cultures were incubated with silver nanoparticles (concentration 10-4 M) and treated with various exposure time of diode laser (15, 30, 45, 60, 75, 90)s. The suspension was planted on Sabouraud Dextrone Agar sterile media and incubated for 24 hours at temperature of 37oC. The number of colony-forming units per milliliter (CFU/ml) was determined after incubation. The results were log-transformed and analyzed by analysis of variance (ANOVA). In this analysis, P value ≤0.05 was considered to indicate a statistically significant difference. The result of this study showed the quantum yield of silver nanoparticles with diode laser 450 nm was 63,61%. Irradiating with diode laser 450 nm for 75 s resulted in the highest decreasing percentage of Candida albicans viability 65,03%. Irradiating with diode laser 450 nm 75 s with silver nanoparticles resulted in the higest decreasing percentage of Candida albicans viability 84,63%. Therefore, silver nanoparticles activated with diode laser irradiation of 450 nm resulted antifungal effect to Candida albicans viability.

  12. Redox-active media for permeable reactive barriers

    International Nuclear Information System (INIS)

    Sivavec, T.M.; Mackenzie, P.D.; Horney, D.P.; Baghel, S.S.

    1997-01-01

    In this paper, three classes of redox-active media are described and evaluated in terms of their long-term effectiveness in treating TCE-contaminated groundwater in permeable reactive zones. Zero-valent iron, in the form of recycled cast iron filings, the first class, has received considerable attention as a reactive media and has been used in about a dozen pilot- and full-scale subsurface wall installations. Criteria used in selecting commercial sources of granular iron, will be discussed. Two other classes of redox-active media that have not yet seen wide use in pilot- or full-scale installations will also be described: Fe(II) minerals and bimetallic systems. Fe(II) minerals, including magnetite (Fe 3 O 4 ), and ferrous sulfide (troilite, FeS), are redox-active and afford TCE reduction rates and product distributions that suggest that they react via a reductive mechanism similar to that which operates in the FeO system. Fe(II) species within the passive oxide layer coating the iron metal may act as electron transfer mediators, with FeO serving as the bulk reductant. Bimetallic systems, the third class of redox-active media, are commonly prepared by plating a second metal onto zero-valent iron (e.g., Ni/Fe and Pd/Fe) and have been shown to accelerate solvent degradation rates relative to untreated iron metal. The long-term effectiveness of this approach, however, has not yet been determined in groundwater treatability tests. The results of a Ni-plated iron column study using site groundwater indicate that a change in reduction mechanism (to catalytic dehydrohalogenation/hydrogenation) accounts for the observed rate enhancement. A significant loss in media reactivity was observed over time, attributable to Ni catalyst deactivation or poisoning. Zero-valent iron systems have not shown similar losses in reactivity in long-term laboratory, pilot or field investigations

  13. Feasibility of High Energy Lasers for Interdiction Activities

    Science.gov (United States)

    2017-12-01

    NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS FEASIBILITY OF HIGH ENERGY LASERS FOR INTERDICTION ACTIVITIES by Carlos Abel Javier Romero... ENERGY LASERS FOR INTERDICTION ACTIVITIES 5. FUNDING NUMBERS 6. AUTHOR(S) Carlos Abel Javier Romero Chero 7. PERFORMING ORGANIZATION NAME(S) AND...the people or cargo. High Energy Laser (HEL) weapons are an effective way to deliver energy precisely from a relative long range. This thesis studies

  14. Optodynamic Phenomena During Laser-Activated Irrigation Within Root Canals

    Science.gov (United States)

    Lukač, Nejc; Gregorčič, Peter; Jezeršek, Matija

    2016-07-01

    Laser-activated irrigation is a powerful endodontic treatment for smear layer, bacteria, and debris removal from the root canal. In this study, we use shadow photography and the laser-beam-transmission probe to examine the dynamics of laser-induced vapor bubbles inside a root canal model and compare ultrasonic needle irrigation to the laser method. Results confirm important phenomenological differences in the two endodontic methods with the laser method resulting in much deeper irrigation. Observations of simulated debris particles show liquid vorticity effects which in our opinion represents the major cleaning mechanism.

  15. Muscle activity characterization by laser Doppler Myography

    Science.gov (United States)

    Scalise, Lorenzo; Casaccia, Sara; Marchionni, Paolo; Ercoli, Ilaria; Primo Tomasini, Enrico

    2013-09-01

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin.

  16. Muscle activity characterization by laser Doppler Myography

    International Nuclear Information System (INIS)

    Scalise, Lorenzo; Casaccia, Sara; Marchionni, Paolo; Ercoli, Ilaria; Tomasini, Enrico Primo

    2013-01-01

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin

  17. Digital Media Use and Social Engagement: How Social Media and Smartphone Use Influence Social Activities of College Students.

    Science.gov (United States)

    Kim, Yonghwan; Wang, Yuan; Oh, Jeyoung

    2016-04-01

    Social media and mobile phones have emerged as important platforms for college students' communication activities. This study examined how college students' psychological need to belong is associated with their use of social media and smartphones. In addition, it further investigated the effects of college students' digital media use on their social engagement. Findings revealed that students' need to belong was positively related with their use of social media and smartphones, which could further facilitate their social engagement. Moreover, the relationship between the need to belong and social engagement was mediated by college students' digital media use. This study offers empirical evidence of the positive effects of digital media on social behaviors and contributed to further understanding about the mechanisms by which need to belong leads to social engagement through digital media use.

  18. High-power laser radiation in atmospheric aerosols: Nonlinear optics of aerodispersed media

    Science.gov (United States)

    Zuev, V. E.; Zemlianov, A. A.; Kopytin, Iu. D.; Kuzikovskii, A. V.

    The bulk of this book contains the results of investigations carried out at the Institute of Atmospheric Optics, Siberian Branch, USSR Academy of Science with the participation of the authors. The microphysical and optical characteristics of atmospheric aerosols are considered, taking into account light scattering by a single aerosol particle, light scattering by a system of particles, the scattering phase matrix, light scattering by clouds and fogs, light scattering by hazes, and scattering phase functions of polydispersed aerosols. Other topics studies are related to low-energy (subexplosive) effects of radiation on individual particles, the formation of clear zones in clouds and fogs due to the vaporization of droplets under regular regimes, self-action of a wave beam in a water aerosol under conditions of regular droplet vaporization, laser beam propagation through an explosively evaporating water-droplet aerosol, the propagation of high-power laser radiation through hazes, the ionization and optical breakdown in aerosol media, and laser monitoring of a turbid atmosphere using nonlinear effects.

  19. Polarization ray tracing in anisotropic optically active media. I. Algorithms

    International Nuclear Information System (INIS)

    McClain, S.C.; Hillman, L.W.; Chipman, R.A.

    1993-01-01

    Procedures for performing polarization ray tracing through birefringent media are presented in a form compatible with the standard methods of geometrical ray tracing. The birefringent materials treated include the following: anisotropic optically active materials such as quartz, non-optically active uniaxial materials such as calcite, and isotropic optically active materials such as mercury sulfide and organic liquids. Refraction and reflection algorithms are presented that compute both ray directions and wave directions. Methods for computing polarization modes, refractive indices, optical path lengths, and Fresnel transmission and reflection coefficients are also specified. A numerical example of these algorithms is given for analyzing the field of view of a quartz rotator. 37 refs., 3 figs

  20. Social TV: How Social Media Activity Interacts With TV Advertising

    OpenAIRE

    Fossen Beth L.; Schweidel David A.

    2017-01-01

    Social TV is the simultaneous consumption of television alongside social media chatter about the programming. This topic is highly relevant for marketers. Usually it is considered as a bad thing for TV advertisers. While there can be distraction from the ads, marketers can also benefit from positive effects. Consumers’ multiscreen activities can be used to attract more viewers, to leverage TV campaigns and to increase sales. This chatter creates free exposure for the brand online, extends the...

  1. Laser Induced Selective Activation For Subsequent Autocatalytic Electroless Plating

    DEFF Research Database (Denmark)

    Zhang, Yang

    . The third hypothesis is that the activation and rinsing process can be described by diffusion. This hypothesis is proved using Fick’s diffusion laws combined with the short-time-plating experiment. The influence of laser parameters on the surface structure is investigated for Nd:YAG, UV, and fiber lasers......The subject of this PhD thesis is “Laser induced selective activation for subsequent autocatalytic electroless plating.” The objective of the project is to investigate the process chains for micro structuring of polymer surfaces for selective micro metallization. Laser induced selective activation...... (LISA) is introduced and studied as a new technique for producing 3D moulded interconnect devices (3D-MIDs). This technique enables the metallization of polymer surface modified by laser and subsequently activated by a PdCl2/SnCl2 system. Various technologies exist on an industrial level...

  2. Advances in nonlinear polymers and inorganic crystals, liquid crystals, and laser media

    International Nuclear Information System (INIS)

    Musikant, S.

    1987-01-01

    These proceedings collect papers on laser materials. Topics include: solid state lasers, fracture mechanics in laser materials, optical second harmonic generation, nonlinear optics, molecular crystals, crystal-phase transformation, and materials for laser fusion reactors

  3. Creating a movement for active living via a media campaign.

    Science.gov (United States)

    Huberty, Jennifer; Dodge, Tammie; Peterson, Kerri R; Balluff, Mary

    2012-11-01

    Activate Omaha (AO), a community-wide health initiative, was awarded a grant by Active Living by Design in 2003. To establish credibility of the partners in AO and increase awareness of active living in the community by emphasizing promotions (branding, logo recognition). Media, including billboards, TV and radio ads, high-profile spokespersons, grassroots efforts, and worksite "toolkits" featuring tips and creative messaging on physical activity were combined to incentivize people to be physically active. Campaign surveys were conducted by the Market Survey Research Group each year from 2005 to 2008. Survey data based on the first campaign indicated that 86% of Omahans wanted to be part of an active community and to be active with younger generations. The second campaign focused on getting families physically active together, and this survey data showed that citizens wanted to be a part of an active community. A third campaign added practical examples of citizens being active within the community and efforts expanded to worksites with consistent messaging for employees. The final survey indicated that 78% of respondents found Omaha to be an active community compared to 63% who had that response 3 years earlier. Activate Omaha was successful in gaining credibility and leveraging additional funding to implement complementary programming and physical projects, and as a result, changing community perceptions and influencing policy decisions. Copyright © 2012 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

  4. Laser Texturing of Magnetic Recording Media Final Report CRADA No. TSV-1298-96

    Energy Technology Data Exchange (ETDEWEB)

    Hackel, L. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marshall, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-10-16

    The Commercial Laser Systems Group at LLNL developed a concept for patterning of computer magnetic recording discs. Magnetic recording media require texturing over areas designated for contact in order to minimize friction with data transducing heads. In fabricating a hard disk, an aluminum nickel-phosphorous substrate was polished to a specular finish then a mechanical means was used to roughen an annular area intended to be the head contact band. In a previous patent (US Patent 5,062,021) it was proposed that the focused output of a low power laser with short pulse length could be used to generate the textured pattern. However, the patterned area typically required 75,000 textured spots that needed to be rapidly (less than 10 seconds) printed with good uniformity. A means to achieve the accurate placement and uniform profile, as well as a meaningfully rapid process time, was not discussed in the referenced patent. The LLNL team devised a system that could rapidly and inexpensively accomplish the texturing.

  5. Media Portrayals of Hashtag Activism: A Framing Analysis of Canada’s #Idlenomore Movement

    OpenAIRE

    Derek Moscato

    2016-01-01

    The confluence of activism and social media - legitimized by efforts such as the Arab Spring and Occupy Movements - represents a growing area of mainstream media focus. Using Canada’s #IdleNoMore movement as a case, this study uses framing theory to better understand how traditional media are representing activism borne of social media such as Twitter, and how such activism can ultimately have an impact in political and public policy debates. A qualitative framing analysis is used to ident...

  6. Activism or Slacktivism? The Potential and Pitfalls of Social Media in Contemporary Student Activism

    Science.gov (United States)

    Cabrera, Nolan L.; Matias, Cheryl E.; Montoya, Roberto

    2017-01-01

    The emergence of social media has greatly influenced 21st-century student activism. It has also given rise to the birth of "slacktivism," an online form of self-aggrandizing, politically ineffective activism. This theoretical article delves into the conceptualizations of what constitutes student activism versus slacktivism in a digital…

  7. Laser stimulation can activate autophagy in HeLa cells

    International Nuclear Information System (INIS)

    Wang, Yisen; Hu, Minglie; Wang, Chingyue; Lan, Bei; Cao, Youjia; He, Hao

    2014-01-01

    For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca 2+ dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

  8. Laser stimulation can activate autophagy in HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yisen; Hu, Minglie; Wang, Chingyue [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China); Lan, Bei; Cao, Youjia [Key Laboratory of Microbial Functional Genomics of Ministry of Education, College of Life Sciences, Nankai University, Tianjin (China); He, Hao, E-mail: haohe@tju.edu.cn [Ultrafast Laser Laboratory, Key Laboratory of Optoelectronic Information Technology (Ministry of Education), College of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin (China); Med-X Research Institute, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai (China)

    2014-10-27

    For decades, lasers have been a daily tool in most biological research for fluorescent excitation by confocal or multiphoton microscopy. More than 20 years ago, cell photodamage caused by intense laser stimulation was noticed by generating reactive oxygen species, which was then thought as the main damage effect by photons. In this study, we show that laser stimulation can induce autophagy, an important cell lysosomal pathway responding to immune stimulation and starvation, without any biochemical treatment. Two different types of laser stimulations are found to be capable of activating autophagy: continuous scanning by continuous-wave visible lasers and a short-time flash of femtosecond laser irradiation. The autophagy generation is independent from wavelength, power, and scanning duration of the visible lasers. In contrast, the power of femtosecond laser is very critical to autophagy because the multiphoton excited Ca{sup 2+} dominates autophagy signaling. In general, we show here the different mechanisms of autophagy generation by such laser stimulation, which correspond to confocal microscopy and cell surgery, respectively. Those results can help further understanding of photodamage and autophagy signaling.

  9. Media Activism and the Academy, Three Cases: Media Democracy Day, Open Media, and NewsWatch Canada

    Directory of Open Access Journals (Sweden)

    David Skinner

    2015-12-01

    Full Text Available In Canada, there is a relatively strong tradition of activist scholarship in media and communication studies. However, very little research has been undertaken on how working in the university may contextualize the ways in which academic workers participate in activist media projects. Focusing on three such projects – Media Democracy Day, Open Media, and NewsWatch Canada – this article draws upon elements of political economy and Bourdieu’s field theory to consider how the different characters of the academic and activist fields work to enable and constrain the abilities of faculty to engage with them.

  10. Trying To Reduce Your Technostress?: Helpful Activities for Teachers and Library Media Specialists.

    Science.gov (United States)

    McKenzie, Barbara K.; And Others

    1997-01-01

    As pressure increases to integrate technology into instruction, many teachers and library media specialists are having difficulty coping with "technostress." Presents suggestions and activities for teachers and library media specialists designed to reduce "technostress." (PEN)

  11. Laser propulsion activity in South Africa

    CSIR Research Space (South Africa)

    Michaelis, MM

    2006-07-01

    Full Text Available hemisphere are becoming excited at the prospect of a considerable reduction in the cost of launch to low Earth orbit (LEO) by means of laser propulsion (LP) (see ref. 1). We argue here that developing nations also should assess the potential of a cheaper... of the grandiose scheme of ‘Space Port Kilimanjaro’ (Fig. 5), envis- aged by various authors becoming a reality, South African scien- tists, engineers and financiers would benefit. Kilimanjaro is regarded by some13 as the prime location for laser propulsion...

  12. LASERS, ACTIVE MEDIA: The aqueous-polyelectrolyte dye solution as an active laser medium

    Science.gov (United States)

    Akimov, A. I.; Saletskii, A. M.

    2000-11-01

    The spectral, luminescent, and lasing properties of aqueous solutions of a cationic dye rhodamine 6G with additions of anion polyelectrolytes — polyacrylic and polymethacrylic acids — are studied. It is found that the energy and spectral properties of lasing of these solutions depend on the ratio of concentrations of polyelectrolyte and molecules. It is also found that the lasing parameters of aqueous-polyelectrolyte dye solutions can be controlled by changing the structure of the molecular system. The variation in the structure of aqueous-polyelectrolyte dye solutions of rhodamine 6G resulted in an almost five-fold increase in the lasing efficiency compared to that in aqueous dye solutions.

  13. Physical activity promotion through the mass media: inception, production, transmission and consumption.

    Science.gov (United States)

    Finlay, Sara-Jane; Faulkner, Guy

    2005-02-01

    Evaluations of physical activity and health media campaigns have been limited and ignore the complex process of communication and the socially constructed nature of news messages. A systematic search strategy was conducted of the literature which was then assessed from two perspectives. First, studies since 1998 were reviewed for their success in impacting message recall and behavior change. Second, employing a critical media studies perspective the papers were assessed for the presence of a more sophisticated understanding of the media processes of inception, transmission and reception. Overall, recent studies support mass media interventions in influencing short-term physical activity message recall and to a lesser extent associated changes in physical activity knowledge. However, the majority of the papers were found to follow a social marketing or media advocacy theory of media promotion with little in-depth consideration of the comprehensive media processes involved in creating media messages and meaning. Simplistic understandings of media transmission dominate in assessing physical activity and health media campaigns. Fuller understandings of the success of media campaigns, the recall of media messages or associated behaviour change can only truly be understood through the application of a more sophisticated form of media analysis.

  14. Interaction of media, sexual activity and academic achievement in adolescents.

    Science.gov (United States)

    Shashi Kumar, R; Das, R C; Prabhu, H R A; Bhat, P S; Prakash, Jyoti; Seema, P; Basannar, D R

    2013-04-01

    Adolescence is a period when the individual is vulnerable and exposure to sexually implicit/explicit programs on television and internet can influence their sexual behaviour and make them more permissive towards premarital sex, which is known to influence their academic performance. This can be modified by parental discussion on these matters with their children. There have been only few studies from India that have explored such issues therefore this study aimed to explore the impact of television, internet and parental discussion on sexual activity and academic performance. This study was conducted in two co-education schools using a self reporting questionnaire administered to students of class IX-XII. This study evaluated the relation of academic performance, exposure to media such as television & internet to sexual activity & academic performance of the students and the role of parental discussion on these. The study sample size was 586. There is no significant association between the number of hours of watching television per day and academic performance as measured by marks in examinations. Significant positive association was found among boys between sexual contact and average score in academics & unsupervised use of internet. In both genders a significant positive association was found between those watching English serials, movies and increased chances of indulging in sexual activity while a negative relation with those watching Cartoons. There is no significant difference in occurrence of sexual contact in those who discussed sexual matters with parents and those who did not. This being first of it's kind of study from India and a cross sectional study, further prospective and detailed studies are warranted to delineate the interaction of media, parental discussion, academic performance and sexual activity.

  15. Tunable diode laser absorption spectroscopy as method of choice for non-invasive and automated detection of microbial growth in media fills.

    Science.gov (United States)

    Brueckner, David; Roesti, David; Zuber, Ulrich; Sacher, Meik; Duncan, Derek; Krähenbühl, Stephan; Braissant, Olivier

    2017-05-15

    Tunable diode laser absorption spectroscopy (TDLAS) was evaluated on its potential to detect bacterial growth of contaminated media fill vials. The target was a replacement/ automation of the traditional visual media fill inspection. TDLAS was used to determine non-invasively O 2 and/or CO 2 changes in headspaces of such vials being induced by metabolically active microorganisms. Four different vial formats, 34 microorganisms (inoculation volume<10 cells) and two different media (TSB/FTM) were tested. Applying parallel CO 2 and O 2 headspace measurements all format-organism combinations were detected within <11 days reliably with reproducible results. False negatives were exclusively observed for samples that were intentionally breached with syringes of 0.3mm in diameter. Overall it was shown that TDLAS functionality for a replacement of the visual media fill inspection is given and that investing in further validation and implementation studies is valuable. Nevertheless, some small but vincible challenges remain to have this technology in practical use. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Social TV: How Social Media Activity Interacts With TV Advertising

    Directory of Open Access Journals (Sweden)

    Fossen Beth L.

    2017-11-01

    Full Text Available Social TV is the simultaneous consumption of television alongside social media chatter about the programming. This topic is highly relevant for marketers. Usually it is considered as a bad thing for TV advertisers. While there can be distraction from the ads, marketers can also benefit from positive effects. Consumers’ multiscreen activities can be used to attract more viewers, to leverage TV campaigns and to increase sales. This chatter creates free exposure for the brand online, extends the reach of television ad campaigns to the online space, and offers real-time feedback to advertisers on how their ads are being received. To take advantage of social TV, marketers need to develop a social media and ad design strategy for TV shows. Not every “social show” is good for them. Many programs receive a high volume of program-related chatter at the expense of advertiser-related word-of-mouth, but some programs generate high levels of online conversations that can also benefit their advertisers. Marketers are well served to identify those programs that are conducive to advertiser-related chatter. Also, specific ad designs can further encourage buzz.

  17. Laser-Doppler acoustic probing of granular media with in-depth property gradient and varying pore pressures

    International Nuclear Information System (INIS)

    Bodet, L.; Dhemaied, A.; Mourgues, R.; Tournat, V.; Rejiba, F.

    2012-01-01

    Non-contacting ultrasonic techniques recently proved to be efficient in the physical modeling of seismic-wave propagation at various application scales, as for instance in the context of geological analogue and seismic modeling. An innovative experimental set-up is proposed here to perform laser-Doppler acoustic probing of unconsolidated granular media with varying pore pressures. The preliminary experiments presented here provide reproducible results and exploitable data, thus validating both the proposed medium preparation and pressure gradient generation procedure.

  18. Photon activation therapy: a Monte Carlo study on dose enhancement by various sources and activation media

    International Nuclear Information System (INIS)

    Bakhshabadi, Mahdi; Ghorbani, Mahdi; Meigooni, Ali Soleimani

    2013-01-01

    In the present study, a number of brachytherapy sources and activation media were simulated using MCNPX code and the results were analyzed based on the dose enhancement factor values. Furthermore, two new brachytherapy sources ( 131 Cs and a hypothetical 170 Tm) were evaluated for their application in photon activation therapy (PAT). 125 I, 103 Pd, 131 Cs and hypothetical 170 Tm brachytherapy sources were simulated in water and their dose rate constant and the radial dose functions were compared with previously published data. The sources were then simulated in a soft tissue phantom which was composed of Ag, I, Pt or Au as activation media uniformly distributed in the tumour volume. These simulations were performed using the MCNPX code, and dose enhancement factor (DEF) was obtained for 7, 18 and 30 mg/ml concentrations of the activation media. Each source, activation medium and concentration was evaluated separately in a separate simulation. The calculated dose rate constant and radial dose functions were in agreement with the published data for the aforementioned sources. The maximum DEF was found to be 5.58 for a combination of the 170 Tm source with 30 mg/ml concentration of I. The DEFs for 131 Cs and 170 Tm sources for all the four activation media were higher than those for other sources and activation media. From this point of view, these two sources can be more useful in photon activation therapy with photon emitter sources. Furthermore, 131 Cs and 170 Tm brachytherapy sources can be proposed as new options for use in the field of PAT.

  19. Three-dimensional imaging of porous media using confocal laser scanning microscopy.

    Science.gov (United States)

    Shah, S M; Crawshaw, J P; Boek, E S

    2017-02-01

    In the last decade, imaging techniques capable of reconstructing three-dimensional (3-D) pore-scale model have played a pivotal role in the study of fluid flow through complex porous media. In this study, we present advances in the application of confocal laser scanning microscopy (CLSM) to image, reconstruct and characterize complex porous geological materials with hydrocarbon reservoir and CO 2 storage potential. CLSM has a unique capability of producing 3-D thin optical sections of a material, with a wide field of view and submicron resolution in the lateral and axial planes. However, CLSM is limited in the depth (z-dimension) that can be imaged in porous materials. In this study, we introduce a 'grind and slice' technique to overcome this limitation. We discuss the practical and technical aspects of the confocal imaging technique with application to complex rock samples including Mt. Gambier and Ketton carbonates. We then describe the complete workflow of image processing to filtering and segmenting the raw 3-D confocal volumetric data into pores and grains. Finally, we use the resulting 3-D pore-scale binarized confocal data obtained to quantitatively determine petrophysical pore-scale properties such as total porosity, macro- and microporosity and single-phase permeability using lattice Boltzmann (LB) simulations, validated by experiments. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

  20. Laser-induced spectrometric techniques to investigate the speciation of Eu in organic media

    International Nuclear Information System (INIS)

    Couston, L.; Roudil, D.; Charbonnel, M.Ch.; Delage, J.; Flandin, J.L.; Mesmin, C.; Rivasseau, C.

    2000-01-01

    Laser-induced spectrometric techniques provide both selectivity and sensitivity. The extremely low detection limits are ideal for assessing the extraction mechanisms involved in enhanced reprocessing applications through detailed speciation studies. Although time-resolved laser-induced fluorescence spectroscopy (TRLIF) is one of the most sensitive spectroscopy techniques, with the optical spectrum and its lifetime constituting two sources of data, it is limited to a few fluorescing actinides and lanthanides. This drawback warrants the development of an additional, complementary spectroscopic system with greater sensitivity than UV-Visible-near IR absorptiometry, based on measuring the pressure wave caused by the deexcitation of non-fluorescing species. Laser-induced photoacoustic spectroscopy (LIPAS) is based on measuring the characteristics of the pressure wave emitted during non-radiative relaxation of the absorbed energy. This speciation technique should allow investigation of compounds that absorb in the UV-visible range and are present at low concentrations in solution. It provides data on the nature and concentration of the species, including its oxidation, complexation and even colloidal states. The two techniques with a common laser source OPO were recently installed at Marcoule. TRLIF speciation studies are generally based on analyzing modifications in the fluorescence spectrum following a short laser pulse. They are related to the characteristic spectral pattern and relaxation rate of each species in solution. In the particular case of fluorescent decay of trivalent Am, Cm, Sm, Eu, Tb and Dy ions, the metallic cation deexcitation constant is closely related to the number of water molecules in the primary coordination sphere. This property helps to obtain more information on the structure around the metal ion. The first study was an investigation of the complexation of Eu(III) by TEMA (N, N'-tetra-ethyl-malonamide (C 2 H 5 ) 2 NCO-CH 2 CON(C 2 H 5 ) 2 ) in

  1. Ball-milled nano-colloids of rare-earth compounds as liquid gain media for capillary optical amplifiers and lasers

    Science.gov (United States)

    Patel, Darayas; Blockmon, Avery; Ochieng, Vanesa; Lewis, Ashley; Wright, Donald M.; Lewis, Danielle; Valentine, Rueben; Valentine, Maucus; Wesley, Dennis; Sarkisov, Sergey S.; Darwish, Abdalla M.; Sarkisov, Avedik S.

    2017-02-01

    Nano-colloids and nano-crystals doped with ions of rare-earth elements have recently attracted a lot of attention in the scientific community due to their potential applications as biomarkers, fluorescent inks, gain media for lasers and optical amplifiers. Many rare-earth doped materials of different compositions, shapes and size distribution have been prepared by different synthetic methods, such as chemical vapor deposition, sol-gel process, micro-emulsion techniques, gas phase condensation methods, hydrothermal methods and laser ablation. In this paper micro-crystalline powder of the rare-earthdoped compound NaYF4:Yb3+, Er3+ was synthesized using a simple wet process followed by baking in open air. Under 980 nm diode laser excitation strong fluorescence in the 100 nm band around 1531-nm peak was observed from the synthesized micro-powder. The micro-powder was pulverized using a ball mill and prepared in the form of nano-colloids in different liquids. The particle size of the obtained nano-colloids was measured using an atomic force microscope and a dynamic light scatterometer. The size of the nano-particles was close to 100-nm. The nano-colloids were utilized as a filling media in capillary optical amplifiers and lasers. The gain of a 7-cm-long capillary optical amplifier (150-micron inner diameter) was as high as 6 dB at 200 mW pump power. The synthesized nano-colloids and the active optical components using them can be potentially used in optical communication, signal processing, optical computing, and other applications.

  2. Measuring social media activities of Dutch museums. : Developing a social media monitor.

    NARCIS (Netherlands)

    Rogier Brussee; Drs Erik Hekman; Thijs Waardenburg

    2014-01-01

    In this paper we discuss the general approach and choices we made in developing a prototype of a social media monitor. The main goal of the museum monitor is to offer museum professionals and researchers better insight in the effects of their own social media usage and compare this with other actors

  3. Stigma's Effect on Social Interaction and Social Media Activity.

    Science.gov (United States)

    Boudewyns, Vanessa; Himelboim, Itai; Hansen, Derek L; Southwell, Brian G

    2015-01-01

    Stigmatized topics, such as HIV/STD, likely constrain related information sharing in ways that should be apparent in social interactions both on and off the Internet. Specifically, the authors predicted that the more people perceive an issue as stigmatized, the less likely they are to talk about the issue both privately (with sexual partners and peers) and publicly (on Twitter). Study 1 tested the effect of stigma on conversations at the individual level: The authors asked a group of participants (N = 138) about perceived STD-testing stigma, interactions with a sexual partner, and conversations with peers about STD testing. Study 2 assessed whether health conditions, in the aggregate, were less likely to generate social media activity as a function of current stigmatization. Using 259,758 archived Twitter posts mentioning 13 medical conditions, the authors tested whether level of stigma predicted the volume of relevant social media conversation, controlling for each condition's amount of advocacy and Google search popularity from a user's perspective. Findings supported our hypotheses. Individuals who reported perceiving a given health conditions in more stigmatic ways also reported interacting less with others about that topic; Twitter results showed a similar pattern. Results also suggest a more complex story of influence, as funding from the National Institutes of Health (i.e., each conditions amount of advocacy) associated with the examined health conditions also predicted Twitter activity. Overall, these results indicated that stigma had a similar, dampening effect on face-to-face and Twitter interactions. Findings hold theoretical and practical implications, which are discussed.

  4. Disability activism in the new media ecology: campaigning strategies in the digital era

    OpenAIRE

    Pearson, Charlotte; Trevisan, Filippo

    2015-01-01

    This article examines the changing nature of disability activism through the influence of social media. As disabled people in the UK have been subjected to acute austerity, this has coincided with a new era of disability activism channelled through increased social media participation. Drawing on the analysis of one group's online activities and a qualitative content analysis of disability protest coverage in traditional news media during the 2012 Paralympic Games, this article positions this...

  5. Lasers. Technology Learning Activity. Teacher Edition. Technology Education Series.

    Science.gov (United States)

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This document contains the materials required for presenting an 8-day competency-based technology learning activity (TLA) designed to introduce students in grades 6-10 to advances and career opportunities in the field of laser technology. The guide uses a series of hands-on exploratory experiences into which activities to help students develop…

  6. Laser ablation studies of Deposited Silver Colloids Active in SERS

    International Nuclear Information System (INIS)

    La Porte, R.T.; Moreno, D.S.; Striano, M.C.; Munnoz, M.M.; Garcia-Ramos, J.V.; Cortes, S.S.; Koudoumas, E.

    2002-01-01

    Laser ablation of deposited silver colloids, active in SERS, is carried out at three different laser wavelengths (KrF, XeCl and Nd:YAG at λ = 248, 308 and 532 nm respectively). Emission form excited neutral Ag and Na atoms, present in the ablation plume, is detected with spectral and temporal resolution. The expansion velocity of Ag in the plume is estimated in ∼1x104m s-1, Low-fluence laser ablation of the colloids yields ionized species that are analyzed by time-of-flight mass spectroscopy. Na+ and Agn+(n≤3) are observed. Composition of the mass spectra and widths of the mass peaks are found to be dependent on laser wavelength, suggesting that the dominant ablation mechanisms are different at the different wavelenghts.

  7. Activity of respiratory system during laser irradiation of brain structures

    Science.gov (United States)

    Merkulova, N. A.; Sergeyeva, L. I.

    1984-06-01

    The performance of one of the principal links of the respiratory system, the respiratory center, was studied as a function of the exposure of the medulla oblongata and the sensomotor zone of the cerebral hemisphere cortex to low level laser irradiation in the red wavelength of the spectrum. Experiments were done on white rats under barbital anesthesia. Under such conditions a substantial effect was observed on the activity of the respiratory center. Laser light may display activating or inhibitory influences, in some cases the bilateral symmetry of the activity of the respiratory center is affected indicating deep changes in the integrative mechanism of the functioning of the right and left sides of the hemispheres. The laser beam effect depends on many factors: specific light properties, duration of the exposure, repetition of exposures, initial functional state of the CNS, etc.

  8. Effects of Near-Infrared Laser on Neural Cell Activity

    International Nuclear Information System (INIS)

    Mochizuki-Oda, Noriko; Kataoka, Yosky; Yamada, Hisao; Awazu, Kunio

    2004-01-01

    Near-infrared laser has been used to relieve patients from various kinds of pain caused by postherpetic neuralgesia, myofascial dysfunction, surgical and traumatic wound, cancer, and rheumatoid arthritis. Clinically, He-Ne (λ=632.8 nm, 780 nm) and Ga-Al-As (805 ± 25 nm) lasers are used to irradiate trigger points or nerve ganglion. However the precise mechanisms of such biological actions of the laser have not yet been resolved. Since laser therapy is often effective to suppress the pain caused by hyperactive excitation of sensory neurons, interactions with laser light and neural cells are suggested. As neural excitation requires large amount of energy liberated from adenosine triphosphate (ATP), we examined the effect of 830-nm laser irradiation on the energy metabolism of the rat central nervous system and isolated mitochondria from brain. The diode laser was applied for 15 min with irradiance of 4.8 W/cm2 on a 2 mm-diameter spot at the brain surface. Tissue ATP content of the irradiated area in the cerebral cortex was 19% higher than that of the non-treated area (opposite side of the cortex), whereas the ADP content showed no significant difference. Irradiation at another wavelength (652 nm) had no effect on either ATP or ADP contents. The temperature of the brain tissue was increased 4.5-5.0 deg. C during the irradiation of both 830-nm and 652-nm laser light. Direct irradiation of the mitochondrial suspension did not show any wavelength-dependent acceleration of respiration rate nor ATP synthesis. These results suggest that the increase in tissue ATP content did not result from the thermal effect, but from specific effect of the laser operated at 830 nm. Electrophysiological studies showed the hyperpolarization of membrane potential of isolated neurons and decrease in membrane resistance with irradiation of the laser, suggesting an activation of potassium channels. Intracellular ATP is reported to regulate some kinds of potassium channels. Possible mechanisms

  9. Profiling, assessing and matching personalities active in social media

    OpenAIRE

    Hennessy, Ciarán; Smeaton, Alan F.

    2016-01-01

    The world of social media influencers, bloggers and online “clothes horses” is a relatively new one. New-media personalities, a.k.a. “clothes horses”, are now endorsing brands, products and companies in a more subtle way than through traditional advertising. They carefully cultivate and position their personal brands with a view to persuading businesses to use them for relatively inexpensive, often local, online marketing campaigns. In the world of traditional media, companies wishing to adve...

  10. Chemical bond activation observed with an x-ray laser

    International Nuclear Information System (INIS)

    Beye, Martin; Öberg, Henrik; Xin, Hongliang

    2016-01-01

    The concept of bonding and anti-bonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Lastly, we apply time-resolved soft X-ray spectroscopy at a free-electron laser to directly observe the decreased bonding–anti-bonding splitting following bond-activation using an ultra short optical laser pulse.

  11. Development of a compact vertical-cavity surface-emitting laser end-pumped actively Q-switched laser for laser-induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuo; Chen, Rongzhang; Nelsen, Bryan; Chen, Kevin, E-mail: pec9@pitt.edu [Department of Electrical and Computer Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Liu, Lei; Huang, Xi; Lu, Yongfeng [Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)

    2016-03-15

    This paper reports the development of a compact and portable actively Q-switched Nd:YAG laser and its applications in laser-induced breakdown spectroscopy (LIBS). The laser was end-pumped by a vertical-cavity surface-emitting laser (VCSEL). The cavity lases at a wavelength of 1064 nm and produced pulses of 16 ns with a maximum pulse energy of 12.9 mJ. The laser exhibits a reliable performance in terms of pulse-to-pulse stability and timing jitter. The LIBS experiments were carried out using this laser on NIST standard alloy samples. Shot-to-shot LIBS signal stability, crater profile, time evolution of emission spectra, plasma electron density and temperature, and limits of detection were studied and reported in this paper. The test results demonstrate that the VCSEL-pumped solid-state laser is an effective and compact laser tool for laser remote sensing applications.

  12. THE EFFECT OF SOCIAL MEDIA MARKETING ACTIVITIES ON BRAND AWARENESS, BRAND IMAGE AND BRAND LOYALTY

    OpenAIRE

    Yusuf BİLGİN

    2018-01-01

    The aim of this research is to examine the effect of social media marketing activities on brand awareness, brand image and brand loyalty. In addition, it has been aimed to analyze the effect of brand awareness and brand image on brand loyalty in this research. The population of the research consists of the consumers who actively follow five brands with the highest social score according to the Marketing Turkey social media brand performance data on social media communication channels such as ...

  13. Gamma-neutron activation experiments using laser wakefield accelerators

    International Nuclear Information System (INIS)

    Leemans, W.P.; Rodgers, D.; Catravas, P.E.; Geddes, C.G.R.; Fubiani, G.; Esarey, E.; Shadwick, B.A.; Donahue, R.; Smith, A.

    2001-01-01

    Gamma-neutron activation experiments have been performed with relativistic electron beams produced by a laser wakefield accelerator. The electron beams were produced by tightly focusing (spot diameter ≅6 μm) a high power (up to 10 TW), ultra-short (≥50 fs) laser beam from a high repetition rate (10 Hz) Ti:sapphire (0.8 μm) laser system, onto a high density (>10 19 cm -3 ) pulsed gasjet of length ≅1.5 mm. Nuclear activation measurements in lead and copper targets indicate the production of electrons with energy in excess of 25 MeV. This result was confirmed by electron distribution measurements using a bending magnet spectrometer. Measured γ-ray and neutron yields are also found to be in reasonable agreement with simulations using a Monte Carlo transport code

  14. Determining Effect of Digital And Media Activities On Media And Science Literacy Of Middle-School Students And Parents

    Directory of Open Access Journals (Sweden)

    Bilge CAN

    2018-01-01

    Full Text Available This research aims determining effect of digital and media activities on media and science literacy of middle-school students and parents and identifying the relationship between them. Quasi- experimental model has been used by which pretest-posttest studies have been held on one group by using quantitative data during research. The sample of the research consists of 60 students and 119 parents who attend a school in the province of Bursa in the academic year of 2013-2014. According to data analysis obtained in the research, there is a significant relation between pretests and posttests about scientific literacy of middle-school students and parents relating to Digital and Media Activities. There is a relation between media and scientific literacy of students and mothers as parents. There is a difference between the applied PISA and TIMSS exams and the students' science literacy. In the light of these results, some suggestion has been offered with regard to focusing on the importance of 21st century skills and literacy, developing scientific and media literacy level and obtaining more comprehensive results.

  15. Assisted Interpretation of Laser-Induced Fluorescence Spectra of Egg-Based Binding Media Using Total Emission Fluorescence Spectroscopy

    International Nuclear Information System (INIS)

    Anglos, D.; Nevin, A.

    2006-01-01

    Laser-induced fluorescence (LIF) spectroscopy can provide nondestructive, qualitative analysis of protein-based binding media found in artworks. Fluorescence emissions from proteins in egg yolk and egg white are due to auto fluorescent aromatic amino acids as well as other native and age-related fluorophores, but the potential of fluorescence spectroscopy for the differentiation between binding media is dependent on the choice of a suitable excitation wavelength and limited by problems in interpretation. However, a better understanding of emission spectra associated with LIF can be achieved following comparisons with total emission fluorescence spectra where a series of consecutive emission spectra are recorded over a specific range. Results using nanosecond UV laser sources for LIF of egg-based binding media are presented which are rationalised following comparisons with total emission spectra. Specifically, fluorescence is assigned to tryptophan and oxidation products of amino acids; in the case of egg yolk, fatty-acid polymerisation and age-related degradation products account for the formation of fluorophores.

  16. Electroless Plating on Plastic Induced by Selective Laser Activation

    DEFF Research Database (Denmark)

    Zhang, Yang; Tang, Peter Torben; Hansen, Hans Nørgaard

    2009-01-01

    This paper presents a new method for selective micro metallization of polymers. A Nd:YAG laser is employed to draw patterns on polymer surfaces that are submerged in a liquid (usually water). After subsequent activation with palladium chloride and followed by auto-catalytic electroless plating, c...

  17. An actively mode-locked Ho: YAG solid laser pumped by a Tm: YLF laser

    International Nuclear Information System (INIS)

    Yao, B Q; Cui, Z; Wang, J; Duan, X M; Dai, T Y; Du, Y Q; Yuan, J H; Liu, W

    2015-01-01

    A continuous wave mode-locked (CWML) Ho: YAG laser based on an acousto-optic modulator (AOM) pumped by a 1.9 μm Tm: YLF laser is demonstrated. This is the first time a report on an active CWML Ho: YAG laser has been published. A maximum output power of 1.04 W at 2097.25 nm in the CWML regime is obtained at a pump power of 13.2 W, corresponding to a slope efficiency of 13.3%. The mode-locked pulse repetition frequency is 82.76 MHz and the single pulse energy is 12.57 nJ. The mode-locked pulse width is 102 ps measured through a no-background second harmonic autocorrelation with KTP as the nonlinear crystal. Furthermore, the M 2 factor is calculated to be 1.146. (letter)

  18. The laser thermonuclear fusion

    International Nuclear Information System (INIS)

    Coutant, J.; Dautray, R.; Decroisette, M.; Watteau, J.P.

    1987-01-01

    Principle of the thermonuclear fusion by inertial confinement: required characteristics of the deuterium-tritium plasma and of the high power lasers to be used Development of high power lasers: active media used; amplifiers; frequency conversion; beam quality; pulse conditioning; existing large systems. The laser-matter interaction: collision and collective interaction of the laser radiation with matter; transport of the absorbed energy; heating and compression of deuterium-tritium; diagnoses and their comparison with the numerical simulation of the experiment; performances. Conclusions: difficulties to overcome; megajoule lasers; other energy source: particles beams [fr

  19. Social media activism and Egyptians' use of social media to combat sexual violence: an HiAP case study.

    Science.gov (United States)

    Peuchaud, Sheila

    2014-06-01

    This paper represents a case study of how social media activists have harnessed the power of Facebook, Twitter and mobile phone networks to address sexual harassment in Egypt. HarassMap plots reports of sexual harassment on a Google Map and informs victims of support services. Tahrir Bodyguard and Operation Anti-Sexual Harassment (OpAntiSH) protect female protestors who have been vulnerable to sexual aggression at the hands of unruly mobs and by agents of the state. Activists have access to an Android app called 'I'm Getting Arrested' or 'Byt2ebed 3alia' in Egyptian Arabic. The app sends the time and GPS coordinates of an arrest to family, fellow activists, legal counsel and social media outlets. The hope is the initiatives described in this paper could inspire public health ministries and activist NGOs to incorporate crowdsourcing social media applications in the spirit of health in all policies (HiAP). To that end, this paper will begin by defining social media activism from the perspective of the communications discipline. This paper will then demonstrate the significance of sexual harassment as a public health issue, and describe several social media efforts to document incidents and protect victims. The paper will conclude with discussion regarding how these innovations could be integrated into the HiAP approach. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  20. Laser metrology and optic active control system for GAIA

    Science.gov (United States)

    D'Angelo, F.; Bonino, L.; Cesare, S.; Castorina, G.; Mottini, S.; Bertinetto, F.; Bisi, M.; Canuto, E.; Musso, F.

    2017-11-01

    The Laser Metrology and Optic Active Control (LM&OAC) program has been carried out under ESA contract with the purpose to design and validate a laser metrology system and an actuation mechanism to monitor and control at microarcsec level the stability of the Basic Angle (angle between the lines of sight of the two telescopes) of GAIA satellite. As part of the program, a breadboard (including some EQM elements) of the laser metrology and control system has been built and submitted to functional, performance and environmental tests. In the followings we describe the mission requirements, the system architecture, the breadboard design, and finally the performed validation tests. Conclusion and appraisals from this experience are also reported.

  1. Laser active thermography for non-destructive testing

    International Nuclear Information System (INIS)

    Semerok, A.; Grisolia, C.; Fomichev, S.V.; Thro, P.Y.

    2013-01-01

    Thermography methods have found their applications in different fields of human activity. The non-destructive feature of these methods along with the additional advantage by automated remote control and tests of nuclear installations without personnel attendance in the contaminated zone are of particular interest. Laser active pyrometry and laser lock-in thermography for in situ non-destructive characterization of micrometric layers on graphite substrates from European tokamaks were under extensive experimental and theoretical studies in CEA (France). The studies were aimed to obtain layer characterization with cross-checking the layer thermal contact coefficients determined by active laser pyrometry and lock-in thermography. The experimental installation comprised a Nd-YAG pulsed repetition rate laser (1 Hz - 10 kHz repetition rate frequency, homogeneous spot) and a home-made pyrometer system based on two pyrometers for the temperature measurements in 500 - 2600 K range. For both methods, the layer characterization was provided by the best fit of the experimental results and simulations. The layer thermal contact coefficients determined by both methods were quite comparable. Though there was no gain in the measurements accuracy, lock-in measurements have proved their advantage as being much more rapid. The obtained experimental and theoretical results are presented. Some practical applications and possible improvements of the methods are discussed. (authors)

  2. Laser active thermography for non-destructive testing

    Science.gov (United States)

    Semerok, A.; Grisolia, C.; Fomichev, S. V.; Thro, P.-Y.

    2013-11-01

    Thermography methods have found their applications in different fields of human activity. The non-destructive feature of these methods along with the additional advantage by automated remote control and tests of nuclear installations without personnel attendance in the contaminated zone are of particular interest. Laser active pyrometry and laser lock-in thermography for in situ non-destructive characterization of micrometric layers on graphite substrates from European tokamaks were under extensive experimental and theoretical studies in CEA (France). The studies were aimed to obtain layer characterization with cross-checking the layer thermal contact coefficients determined by active laser pyrometry and lock-in thermography. The experimental installation comprised a Nd-YAG pulsed repetition rate laser (1 Hz - 10 kHz repetition rate frequency, homogeneous spot) and a home-made pyrometer system based on two pyrometers for the temperature measurements in 500 - 2600 K range. For both methods, the layer characterization was provided by the best fit of the experimental results and simulations. The layer thermal contact coefficients determined by both methods were quite comparable. Though there was no gain in the measurements accuracy, lock-in measurements have proved their advantage as being much more rapid. The obtained experimental and theoretical results are presented. Some practical applications and possible improvements of the methods are discussed.

  3. Development of activated charcoal impregnated air sampling filter media : their characteristics and use

    International Nuclear Information System (INIS)

    Khan, A.A.; Ramarathinam, K.; Gupta, S.K.; Deshingkar, D.S.; Kishore, A.G.

    1975-01-01

    Because of its low maximum permissible concentration in air, air-borne radioiodine must be accurately monitored in contaminated air streams, in the working environment and handling facilities, before release to the environment from the nuclear facilities. Activated charcoal impregnated air sampling filter media are found to be most suitable for monitoring airborne iodine-131. Because of its simplicity and reproducible nature in assessment of air-borne radioactive iodine, the work on the development of such media was undertaken in order to find a suitable substitute for imported activated charcoal impregnated air sampling filter media. Eight different media of such type were developed, evaluated and compared with two imported media. Best suitable medium is recommended for its use in air-borne iodine sampling which was found to be even better suited than imported media of such type. (author)

  4. Utilizing Social Media to Further the Nationwide Suspicious Activity Reporting Initiative

    Science.gov (United States)

    2012-09-01

    Initiative NYPD New York Police Department OSINT Open Source Intelligence P2P Peer to Patent SAR Suspicious Activity Report SMS Short Message (or...Media as an Open-Source Intelligence Tool Several government documents outline the use of social media as an Open Source intelligence tool ( OSINT ...social media to be an OSINT tool that federal, state, and local law enforcement agencies should use to develop timely, relevant, and actionable

  5. Brain activation upon ideal-body media exposure and peer feedback in late adolescent girls

    OpenAIRE

    van der Meulen, Mara; Veldhuis, Jolanda; Braams, Barbara R.; Peters, Sabine; Konijn, Elly A.; Crone, Eveline A.

    2017-01-01

    Media?s prevailing thin-body ideal plays a vital role in adolescent girls? body image development, but the co-occurring impact of peer feedback is understudied. The present study used functional magnetic resonance imaging (fMRI) to test media imagery and peer feedback combinations on neural activity related to thin-body ideals. Twenty-four healthy female late adolescents rated precategorized body sizes of bikini models (too thin or normal), directly followed by ostensible peer feedback (too t...

  6. Self-reflection and self-transmission of pulsed radiation by laser-evaporated media

    Science.gov (United States)

    Furzikov, Nickolay P.

    1991-05-01

    Analysis of the known laser-induced evaporation (thermodestruction) model predicts the quasiperiodic oscillation of the effective absorption depth between its normal value and some minute quantity consisting of a part of the incident wavelength. This prediction explains the experimental data on the polymer laser ablation depth as well as the reflection transient drop of the laserdestructed aluminum.

  7. Social Media and the Idle No More Movement: Citizenship, Activism and Dissent in Canada

    Science.gov (United States)

    Tupper, Jennifer

    2014-01-01

    This paper, informed by a critique of traditional understandings of citizenship and civic education, explores the use of social media as a means of fostering activism and dissent. Specifically, the paper explores the ways in which the Idle No More Movement, which began in Canada in 2012 marshalled social media to educate about and protest Bill…

  8. Utilising the Mass Media for the Promotion of Religious Activities in ...

    African Journals Online (AJOL)

    Utilising the Mass Media for the Promotion of Religious Activities in Nigeria. ... The media have the ability to communicate religious messages that will enable ... to promote moral attitudes in our people, which will in turn, lead to development in ...

  9. Microwave-assisted synthesis of bio-active heterocycles in aqueous media

    KAUST Repository

    Polshettiwar, Vivek

    2010-01-01

    Synthesis of bio-active heterocycles and fine chemicals in aqueous media are one of the best solutions for the development of green and sustainable protocols. To illustrate the advantages of aqueous MW chemistry in heterocycle synthesis, in this chapter, various synthetic pathways developed in recent years in aqueous reaction media using microwave irradiation are described.

  10. Effect of liquid active media on grinding and scratching of solids

    International Nuclear Information System (INIS)

    Pertsov, N.V.; Danilova, F.B.; Babat, I.G.

    1975-01-01

    In the present paper the influence of various liquid active media on grinding of tungsten carbide, hard alloy T 15 K 6, oxide of aluminium A995 and other materials with diamond grinding wheels is investigated. A grinding device is described. The results of the investigations show that materials with metallic type of bonds are most effectively treated in the medium of liquid metals; for material with an ionic structure the active media are water and aqueous solutions of electrolytes. It is pointed out that liquid active media will diminish the specific work of dispergation by as much as one order of magnitude

  11. Recycling of pneumatic scrap tyre into nano-crumb rubber by pulsed laser ablation in different pH media

    Science.gov (United States)

    Ezaan Khamsan, Nur; Bidin, Noriah; Islam, Shumaila; Daud, Suzairi; Krishnan, Ganesan; Bakar, Mohamad Aizat A.; Naqiuddin Razali, Muhamad; Khamis, Jamil

    2018-05-01

    Nano crumb rubber from scrap tyre is synthesized via 1064 nm pulsed Nd:YAG laser ablation in three different pH media i.e. DI-water (pH∼6.45), D-limonene (pH∼3.47) and NaOH solution (pH∼13.41). Field Emission Scanning Electron Microscope (FESEM) results show spherical morphology of crumb rubber with high degree of aggregation in DI-water and in D-limonene. However, dispersion of crumb rubbers is observed in NaOH solution. The smallest particles size is obtained in NaOH solution within the range of 10.9 nm – 74.3 nm. Energy-dispersive X-ray spectroscopy (EDX) and FTIR analysis confirmed the elements distribution and chemical bonding of rubber with DI-water, D-limonene and NaOH solution. The experimental findings shows that pulsed Nd:YAG laser ablation has potential for fabricating nano-crumb rubber in liquid media.

  12. Research on range-gated laser active imaging seeker

    Science.gov (United States)

    You, Mu; Wang, PengHui; Tan, DongJie

    2013-09-01

    Compared with other imaging methods such as millimeter wave imaging, infrared imaging and visible light imaging, laser imaging provides both a 2-D array of reflected intensity data as well as 2-D array of range data, which is the most important data for use in autonomous target acquisition .In terms of application, it can be widely used in military fields such as radar, guidance and fuse. In this paper, we present a laser active imaging seeker system based on range-gated laser transmitter and sensor technology .The seeker system presented here consist of two important part, one is laser image system, which uses a negative lens to diverge the light from a pulse laser to flood illuminate a target, return light is collected by a camera lens, each laser pulse triggers the camera delay and shutter. The other is stabilization gimbals, which is designed to be a rotatable structure both in azimuth and elevation angles. The laser image system consists of transmitter and receiver. The transmitter is based on diode pumped solid-state lasers that are passively Q-switched at 532nm wavelength. A visible wavelength was chosen because the receiver uses a Gen III image intensifier tube with a spectral sensitivity limited to wavelengths less than 900nm.The receiver is image intensifier tube's micro channel plate coupled into high sensitivity charge coupled device camera. The image has been taken at range over one kilometer and can be taken at much longer range in better weather. Image frame frequency can be changed according to requirement of guidance with modifiable range gate, The instantaneous field of views of the system was found to be 2×2 deg. Since completion of system integration, the seeker system has gone through a series of tests both in the lab and in the outdoor field. Two different kinds of buildings have been chosen as target, which is located at range from 200m up to 1000m.To simulate dynamic process of range change between missile and target, the seeker system has

  13. Value added cleaning and disinfection of the root canal: laser-activated irrigation and laser-induced photoporation

    Science.gov (United States)

    De Moor, Roeland J. G.; Meire, Maarten A.

    2016-03-01

    Among present-day marketed systems ultrasonic activation appears to be the best way to activate and potentiate endodontic irrigants. An alternative for ultrasonic activation of irrigants is laser activated irrigation (LAI) or photoninitiated acoustic streaming. Based on present-day research it appears that LAI (especially with Erbium lasers) can be more efficient for debris removal out of root canals and interaction with the endodontic biofilms thanks to the induction of specific cavitation phenomena and acoustic streaming. Other wavelengths are now explored to be used for LAI. Another way to interact with biofilms is to rely on laser-induced photoporation in combination with gold nanoparticles ( AuNPs). The latter is an alternative physical method for delivering macromolecules in cells. Nanosized membrane pores can be created upon pulsed laser illumination. Depending on the laser energy, pores are created through either direct heating of the AuNPs or by vapour nanobubbles that can emerge around the AuNPs.

  14. Physical Activity Mass Media Campaigns and Their Evaluation: A Systematic Review of the Literature 2003-2010

    Science.gov (United States)

    Leavy, Justine E.; Bull, Fiona C.; Rosenberg, Michael; Bauman, Adrian

    2011-01-01

    Internationally, mass media campaigns to promote regular moderate-intensity physical activity have increased recently. Evidence of mass media campaign effectiveness exists in other health areas, however the evidence for physical activity is limited. The purpose was to systematically review the literature on physical activity mass media campaigns,…

  15. Complex-envelope alternating-direction-implicit FDTD method for simulating active photonic devices with semiconductor/solid-state media.

    Science.gov (United States)

    Singh, Gurpreet; Ravi, Koustuban; Wang, Qian; Ho, Seng-Tiong

    2012-06-15

    A complex-envelope (CE) alternating-direction-implicit (ADI) finite-difference time-domain (FDTD) approach to treat light-matter interaction self-consistently with electromagnetic field evolution for efficient simulations of active photonic devices is presented for the first time (to our best knowledge). The active medium (AM) is modeled using an efficient multilevel system of carrier rate equations to yield the correct carrier distributions, suitable for modeling semiconductor/solid-state media accurately. To include the AM in the CE-ADI-FDTD method, a first-order differential system involving CE fields in the AM is first set up. The system matrix that includes AM parameters is then split into two time-dependent submatrices that are then used in an efficient ADI splitting formula. The proposed CE-ADI-FDTD approach with AM takes 22% of the time as the approach of the corresponding explicit FDTD, as validated by semiconductor microdisk laser simulations.

  16. Effects of various polishing media and techniques on the surface finish and behavior of laser glasses

    International Nuclear Information System (INIS)

    Landingham, R.L.; Casey, A.W.; Lindahl, R.O.

    1978-01-01

    The advance of high-power laser technology is dependent on the rate of advancement in laser glass forming and surface preparation. The threshold damage of glass surfaces continues to be a weak link in the overall advancement of laser technology. Methods were developed and used in the evaluation of existing glass surface preparation techniques. Modified procedures were evaluated to reduce surface contamination and subsurface defects. Polishing rates were monitored under controlled polishing conditions (purity, pH, particle size distribution, particle concentration, etc.). Future work at LLL for this ongoing investigation is described

  17. Dielectrophoretic focusing integrated pulsed laser activated cell sorting

    Science.gov (United States)

    Zhu, Xiongfeng; Kung, Yu-Chun; Wu, Ting-Hsiang; Teitell, Michael A.; Chiou, Pei-Yu

    2017-08-01

    We present a pulsed laser activated cell sorter (PLACS) integrated with novel sheathless size-independent dielectrophoretic (DEP) focusing. Microfluidic fluorescence activated cell sorting (μFACS) systems aim to provide a fully enclosed environment for sterile cell sorting and integration with upstream and downstream microfluidic modules. Among them, PLACS has shown a great potential in achieving comparable performance to commercial aerosol-based FACS (>90% purity at 25,000 cells sec-1). However conventional sheath flow focusing method suffers a severe sample dilution issue. Here we demonstrate a novel dielectrophoresis-integrated pulsed laser activated cell sorter (DEP-PLACS). It consists of a microfluidic channel with 3D electrodes laid out to provide a tunnel-shaped electric field profile along a 4cmlong channel for sheathlessly focusing microparticles/cells into a single stream in high-speed microfluidic flows. All focused particles pass through the fluorescence detection zone along the same streamline regardless of their sizes and types. Upon detection of target fluorescent particles, a nanosecond laser pulse is triggered and focused in a neighboring channel to generate a rapidly expanding cavitation bubble for precise sorting. DEP-PLACS has achieved a sorting purity of 91% for polystyrene beads at a throughput of 1,500 particle/sec.

  18. A Desire for Social Media Is Associated With a Desire for Solitary but Not Social Activities.

    Science.gov (United States)

    Hill, Lauren; Zheng, Zane

    2017-01-01

    While social media is an aspect of life for many, it brings to light the lack of interpersonal connection when browsing activity occurs. The displacement theory suggests that the quality of one's offline interactions is affected by how much time an individual allots to those exchanges. Depending on the amount of time spent online, interpersonal connections may suffer and lead to negative psychological consequences. Our study aimed to explore the relationship between the desirability of social media and socialization preferences through a cue-based perceptual judgment task where participants ( N = 136) rated 40 gray-scale images in terms of their desirability. The image categories included social media icons, singular scenes depicting an isolated activity, social scenes representing an interactive activity, and traffic signs as the control. We also included questionnaires to assess depressiveness and aspects of social media usage. Our findings suggest that the immediate desire for social media is potentially linked to one's desire for social isolation as represented by the singular scene category, the intensity of participant's reported daily usage, and the extent to which social media is perceived to impact real social life. To our knowledge, this is the first report on the initial desirability judgment of social media and its association with other factors. Further research is needed to distinguish the variability in users' aim of using social media and if that is related to one's perceived feelings of social connectedness and solitude.

  19. Influence of Culture Media on Detection of Carbapenem Hydrolysis by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.

    Science.gov (United States)

    Ramos, Ana Carolina; Carvalhaes, Cecília Godoy; Cordeiro-Moura, Jhonatha Rodrigo; Rockstroh, Anna Carolina; Machado, Antonia Maria Oliveira; Gales, Ana Cristina

    2016-07-01

    In this study, we evaluated the influence of distinct bacterial growth media on detection of carbapenemase hydrolysis by matrix-assisted laser desorption ionization-time of flight mass spectrometry. False-negative results were observed for OXA-25-, OXA-26-, and OXA-72-producing Acinetobacter baumannii isolates grown on MacConkey agar medium. The other culture media showed 100% sensitivity and 100% specificity for detecting carbapenemase. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Peculiarities of the statistics of spectrally selected fluorescence radiation in laser-pumped dye-doped random media

    Science.gov (United States)

    Yuvchenko, S. A.; Ushakova, E. V.; Pavlova, M. V.; Alonova, M. V.; Zimnyakov, D. A.

    2018-04-01

    We consider the practical realization of a new optical probe method of the random media which is defined as the reference-free path length interferometry with the intensity moments analysis. A peculiarity in the statistics of the spectrally selected fluorescence radiation in laser-pumped dye-doped random medium is discussed. Previously established correlations between the second- and the third-order moments of the intensity fluctuations in the random interference patterns, the coherence function of the probe radiation, and the path difference probability density for the interfering partial waves in the medium are confirmed. The correlations were verified using the statistical analysis of the spectrally selected fluorescence radiation emitted by a laser-pumped dye-doped random medium. Water solution of Rhodamine 6G was applied as the doping fluorescent agent for the ensembles of the densely packed silica grains, which were pumped by the 532 nm radiation of a solid state laser. The spectrum of the mean path length for a random medium was reconstructed.

  1. High intensity vacuum ultraviolet and extreme ultraviolet production by noncollinear mixing in laser vaporized media

    Energy Technology Data Exchange (ETDEWEB)

    Todt, Michael A.; Albert, Daniel R.; Davis, H. Floyd, E-mail: hfd1@cornell.edu [Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301 (United States)

    2016-06-15

    A method is described for generating intense pulsed vacuum ultraviolet (VUV) and extreme ultraviolet (XUV) laser radiation by resonance enhanced four-wave mixing of commercial pulsed nanosecond lasers in laser vaporized mercury under windowless conditions. By employing noncollinear mixing of the input beams, the need of dispersive elements such as gratings for separating the VUV/XUV from the residual UV and visible beams is eliminated. A number of schemes are described, facilitating access to the 9.9–14.6 eV range. A simple and convenient scheme for generating wavelengths of 125 nm, 112 nm, and 104 nm (10 eV, 11 eV, and 12 eV) using two dye lasers without the need for dye changes is described.

  2. Framing CSR fit: How corporate social responsibility activities are covered by news media

    NARCIS (Netherlands)

    Lunenberg, Katharina; Gosselt, Jordi Franciscus; de Jong, Menno D.T.

    2016-01-01

    This research provides a basis for understanding how the contents of media coverage about CSR activities relates to the fit between these CSR activities and the organizations’ core activities. In two steps, 513 news articles about organizations’ CSR activities were analyzed. First, an expert review

  3. Interferometric laser detection of nanomechanical perturbations in biological media under ablation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Bonilla, S; Torres-Torres, C; Urriolagoitia-Sosa, G; Hernandez-Gomez, L H; Urriolagoitia-Calderon, G, E-mail: crstorres@yahoo.com.mx [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion Escuela Superior de Ingenieria Mecanica y Electrica Unidad Profesional Adolfo Lopez Mateos ' Zacatenco' Col. Lindavista, CP 07738, Mexico, D. F. (Mexico)

    2011-07-19

    This article has to do with the development of a reliable and sensitive non-invasive laser technique for assessing damage of structures and systems involved in laser ablation processes. The optical response of a Michelson Interferometer in combination with a Measuring Reflectance System has been analyzed in order to identify the stability of the mechanical properties of the sample, the physical perturbations associated with the systems and the environment where the target is contained. This test includes the use of a cyan laser system with 10 mW at 488 nm wavelength as optical source. We found out that with the inclusion of an optical feedback in a sensing system it is possible to determine the modification of the physical properties exhibited by a biological medium under sharp ablation conditions with a high accuracy degree. The results reported in this research have potential applications related to the amount of light intensity that can be tolerated by human tissue. A wide array of disciplines, such as medicine, mechanical industry and optical instrumentation can benefit from this ultrafast optical feedback for controlling high intensity laser signals. Collateral damage of tissue around the laser irradiated zones can be reduced by using intelligent lasers systems with ultra-short temporal response.

  4. Interferometric laser detection of nanomechanical perturbations in biological media under ablation conditions

    International Nuclear Information System (INIS)

    Morales-Bonilla, S; Torres-Torres, C; Urriolagoitia-Sosa, G; Hernandez-Gomez, L H; Urriolagoitia-Calderon, G

    2011-01-01

    This article has to do with the development of a reliable and sensitive non-invasive laser technique for assessing damage of structures and systems involved in laser ablation processes. The optical response of a Michelson Interferometer in combination with a Measuring Reflectance System has been analyzed in order to identify the stability of the mechanical properties of the sample, the physical perturbations associated with the systems and the environment where the target is contained. This test includes the use of a cyan laser system with 10 mW at 488 nm wavelength as optical source. We found out that with the inclusion of an optical feedback in a sensing system it is possible to determine the modification of the physical properties exhibited by a biological medium under sharp ablation conditions with a high accuracy degree. The results reported in this research have potential applications related to the amount of light intensity that can be tolerated by human tissue. A wide array of disciplines, such as medicine, mechanical industry and optical instrumentation can benefit from this ultrafast optical feedback for controlling high intensity laser signals. Collateral damage of tissue around the laser irradiated zones can be reduced by using intelligent lasers systems with ultra-short temporal response.

  5. Interferometric laser detection of nanomechanical perturbations in biological media under ablation conditions

    Science.gov (United States)

    Morales-Bonilla, S.; Torres-Torres, C.; Urriolagoitia-Sosa, G.; Hernández-Gómez, L. H.; Urriolagoitia-Calderón, G.

    2011-07-01

    This article has to do with the development of a reliable and sensitive non-invasive laser technique for assessing damage of structures and systems involved in laser ablation processes. The optical response of a Michelson Interferometer in combination with a Measuring Reflectance System has been analyzed in order to identify the stability of the mechanical properties of the sample, the physical perturbations associated with the systems and the environment where the target is contained. This test includes the use of a cyan laser system with 10 mW at 488 nm wavelength as optical source. We found out that with the inclusion of an optical feedback in a sensing system it is possible to determine the modification of the physical properties exhibited by a biological medium under sharp ablation conditions with a high accuracy degree. The results reported in this research have potential applications related to the amount of light intensity that can be tolerated by human tissue. A wide array of disciplines, such as medicine, mechanical industry and optical instrumentation can benefit from this ultrafast optical feedback for controlling high intensity laser signals. Collateral damage of tissue around the laser irradiated zones can be reduced by using intelligent lasers systems with ultra-short temporal response.

  6. Making inferences about patterns in wildlife tourism activities in Scotland using social media

    OpenAIRE

    Mancini, Francesca

    2016-01-01

    The Power Point file contains the slides of my talk for the BES 2016 annual meeting. The title of the talk is: "Making inferences about patterns in wildlife tourism activities in Scotland using social media".

  7. Microwave-assisted synthesis of bio-active heterocycles in aqueous media

    KAUST Repository

    Polshettiwar, Vivek; Varma, Rajender S.

    2010-01-01

    Synthesis of bio-active heterocycles and fine chemicals in aqueous media are one of the best solutions for the development of green and sustainable protocols. To illustrate the advantages of aqueous MW chemistry in heterocycle synthesis

  8. Social media as a tool for positioning of youth non-governmental organizations activity

    Directory of Open Access Journals (Sweden)

    M. A. Shvab

    2014-09-01

    Full Text Available The article is devoted to the social media analysis, as an important tool of the mass media in the youth non-governmental organizations activity. The article is about special popularity of social media among youth because of the rapid information technologies development. The author emphasizes that social media is a main online channel of communication among young generation, that should be taken into the consideration during the external communication creation. Youth organizations often use social media for target audience involvement, information dissimilation and exchange, service promotion and online dialogue. The author analyses different social media tools, such as: blogs, microblogs (Twitter, social networking sites (Facebook, VKontakte, video-sharing websites (YouTube and others. All these tools are easy in use, do not need any special skills and resources, they are low-cost as well. The author considers that it would be useful to include the organization’s Internet addresses on all social media websites and in traditional media publications, to make it as easy as possible for customers to find the youth non-governmental organizations they are looking for among the broad range of social media communities and services.

  9. A firm's activity in social media and its relationship with corporate reputation, firm size and firm performance

    OpenAIRE

    Mäkinen, Hanna

    2015-01-01

    The significance of social media has increased greatly in the past few years, leading companies to increase their social media activity and also increase their interest in knowing whether it is genuinely worth being active on social media, including knowing the potential advantages. This study aims to examine the relationship between social media activity and three variables: reputation, firm size and firm performance. The study analyzes the relationships between the constru...

  10. Use of mass-media and active involvement in a national dental health campaign in Scotland

    DEFF Research Database (Denmark)

    Schou, L

    1987-01-01

    This paper describes the evaluation of a Dental Health Mass-Media Campaign directed at 5-7-yr-old children and their mothers. It aimed at increasing knowledge and awareness of dental health by making use of three different components: inserts in women's magazines; television commercial; material...... that future national health education campaigns combine the mass-media approach to increase health awareness with active involvement activities to stimulate behavioural changes....

  11. Engaging luxury consumers in social media : Does active consumer engagement influence brand image?

    OpenAIRE

    Åvall, Martina

    2017-01-01

    This study aimed to investigate the effects of active consumer engagement within social media based brand communities on the brand image and luxury consumers’ desire to pur-chase luxury goods. The purpose of this study was to prove that by actively engaging con-sumers on social media luxury brands can positively influence the way consumers perceive the brand and through it increase consumers’ intention to purchase their products and services. Secondary research was carried out through col...

  12. Simple fabrication of active electrodes using direct laser transference

    International Nuclear Information System (INIS)

    Cavallo, P.; Coneo Rodriguez, R.; Broglia, M.; Acevedo, D.F.; Barbero, C.A.

    2014-01-01

    Highlights: •Electroactive materials can be transferred using a single pulse of laser light. •The transfer is made in air using a 6 ns pulse of Nd-YAG laser (532 or 1064 nm). •Conducting polymers films can be transferred maintaining the electroactivity. •Conducting polymer multilayers can be deposited using successive pulses. •Metallic (Au, Pt) transferred micro/nanoparticles are electrocatalytic. -- Abstract: Direct laser transference (DLT) method is applied to obtain electrodes modified with thin films of conducting polymers (CPs) or catalytic metals. A short (6–10 ns) pulse of laser light (second harmonic of Nd-YAG Laser, λ = 532 nm) is shined on the backside of a thin (<200 nm) film of the material to be transferred, which is deposited on a transparent substrate. The illuminated region heats up and the material (conducting polymer or metal) is thermally transferred to a solid target placed at short distance in air. In that ways, CPs are transferred onto polypropylene, glass, indium doped tin oxide (ITO), glassy carbon and gold films. In the same manner, electrocatalytic metals (platinum or gold) are transferred onto conductive substrates (glassy carbon or ITO films on glass). The films have been characterized by scanning electron microscopy, cyclic voltammetry, atomic force microscopy, UV-visible and Fourier Transform Infrared spectroscopies. The chemical, electrical and redox properties of the polymeric materials transferred remain unaltered after the transfer. Moreover, CP multilayers can be built applying DLT several times onto the same substrate. Besides polyaniline, it is shown that it is also possible to transfer functionalized polyanilines. The electrode modified with transferred Pt shows electrocatalytic activity toward methanol oxidation while ferricyanide shows a quasireversible behavior on electrodes modified with transferred Au. The method is simple and fast, works in air without complex environmental conditions and can produce active

  13. Social Activity, School-Related Activity, and Anti-Substance Use Media Messages on Adolescent Tobacco and Alcohol Use

    OpenAIRE

    Moon, Sung Seek; Rao, Uma

    2011-01-01

    In this article, we present the effects of three hypothesized protective factors: social activities, school-related activities, and anti-substance use media messages on adolescent tobacco and alcohol use. Data were drawn from the “Monitoring the Future” (MTF) research project, which was conducted by the Institute for Social Research at the University of Michigan. The sample included 2,551 twelfth-grade students. The results of the structural equation model showed that exposure to media anti-d...

  14. Enhancement of fluorescence, photo-physical parameters and laser performance of pyrromethene (PM597) laser dye by Ag nanoparticles in different media

    Energy Technology Data Exchange (ETDEWEB)

    Alhijry, Ibraheem A. [National Institute of Laser Enhanced Sciences, Cairo University, 12613 Giza (Egypt); Physics Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Faculty of Education, Department of Physics, Hajjah University, Hajjah (Yemen); Gadallah, A.-S. [National Institute of Laser Enhanced Sciences, Cairo University, 12613 Giza (Egypt); Abdelkader, H.I. [Physics Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Abou Kana, Maram T.H., E-mail: mabou202@niles.edu.eg [National Institute of Laser Enhanced Sciences, Cairo University, 12613 Giza (Egypt)

    2016-03-15

    The effect of surface plasmon resonance (SPR) of silver nanoparticles (Ag NPs), exposure to radiation, on the optical and photo-physical properties of pyrromethene (PM597) laser dye in liquid and solid media was assessed. 2-hydroxyethyl methacrylate was used as homo-monomer and homo-polymer, while 2-hydroxyethyl methacrylate / methyl methacrylate were used as co-monomer and co-polymer hosts. Ag NPs was prepared and confirmed its size by high resolution transmission electron microscope (HRTEM), UV/vis absorption spectroscopy and also, theoretically by using Mie theory. The molar concentration of prepared NPs was C=3.39×10{sup −9} mol/L. 40% C (1.356×10{sup −9} mol/L) Ag NPs was found to have the optimum distance with (1×10{sup −4} mol/L PM597 in liquid medium and 1×10{sup −3} mol/L PM597 in solid medium) dye molecules according to Metal Enhancement Fluorescence (MEF) model. [40% C Ag NPs: 1×10{sup −3} mol/L PM597] complex samples had 3.12 cm{sup −1} and 3.89 cm{sup −1} gain values in homo-and co-polymer media, while parent PM597 dye had 2.5 cm{sup −1} and 3.45 cm{sup −1} gain values. Also, amplified spontaneous emission (ASE) value of complex samples was 0.455% and 0.538% in case of homo- and co-polymer respectively. While it was 0.4% and 0.457% in case of parent PM597 dye in the same sequent media. Finally, photo-stabilities of complex samples had higher values in co-monomer and co-polymer hosts compared with respect to their stabilities in homo-monomer and homo-polymer hosts.

  15. Enhancement of fluorescence, photo-physical parameters and laser performance of pyrromethene (PM597) laser dye by Ag nanoparticles in different media

    International Nuclear Information System (INIS)

    Alhijry, Ibraheem A.; Gadallah, A.-S.; Abdelkader, H.I.; Abou Kana, Maram T.H.

    2016-01-01

    The effect of surface plasmon resonance (SPR) of silver nanoparticles (Ag NPs), exposure to radiation, on the optical and photo-physical properties of pyrromethene (PM597) laser dye in liquid and solid media was assessed. 2-hydroxyethyl methacrylate was used as homo-monomer and homo-polymer, while 2-hydroxyethyl methacrylate / methyl methacrylate were used as co-monomer and co-polymer hosts. Ag NPs was prepared and confirmed its size by high resolution transmission electron microscope (HRTEM), UV/vis absorption spectroscopy and also, theoretically by using Mie theory. The molar concentration of prepared NPs was C=3.39×10 −9 mol/L. 40% C (1.356×10 −9 mol/L) Ag NPs was found to have the optimum distance with (1×10 −4 mol/L PM597 in liquid medium and 1×10 −3 mol/L PM597 in solid medium) dye molecules according to Metal Enhancement Fluorescence (MEF) model. [40% C Ag NPs: 1×10 −3 mol/L PM597] complex samples had 3.12 cm −1 and 3.89 cm −1 gain values in homo-and co-polymer media, while parent PM597 dye had 2.5 cm −1 and 3.45 cm −1 gain values. Also, amplified spontaneous emission (ASE) value of complex samples was 0.455% and 0.538% in case of homo- and co-polymer respectively. While it was 0.4% and 0.457% in case of parent PM597 dye in the same sequent media. Finally, photo-stabilities of complex samples had higher values in co-monomer and co-polymer hosts compared with respect to their stabilities in homo-monomer and homo-polymer hosts.

  16. Practical and ethical considerations for using social media in community consultation and public disclosure activities.

    Science.gov (United States)

    Galbraith, Kyle L

    2014-10-01

    Social media are becoming increasingly integrated into both the clinical and the research dimensions of emergency medicine. They can provide methods for sharing crucial information to targeted individuals or groups in a rapid fashion. As a result, investigators conducting emergency research under the exception from prospective informed consent requirements are beginning to turn to social media platforms as they engage in required community consultation and public disclosure activities before their research begins. At present, there are limited data regarding how effectively social media have been used for performing those consultation and disclosure activities. This article offers investigators four specific areas to consider before using social media in consultation and outreach efforts. First, understand the forms of outreach social media platforms can provide. Second, recognize how those outreach methods relate to the specific goals of community consultation and public disclosure. Third, consider whether or not the intended audiences of community consultation and public disclosure will be available via social media. Finally, think about how social media outreach efforts will be measured and assessed before consultation and disclosure activities are under way. © 2014 by the Society for Academic Emergency Medicine.

  17. Laser Technology.

    Science.gov (United States)

    Gauger, Robert

    1993-01-01

    Describes lasers and indicates that learning about laser technology and creating laser technology activities are among the teacher enhancement processes needed to strengthen technology education. (JOW)

  18. Theoretical Analysis of The Use of Social Media in The Enterprise Activity

    Directory of Open Access Journals (Sweden)

    Monika Donculaitė

    2017-06-01

    Full Text Available The purpose of the article is to present the results of analysis of scientific literature on the social media concept and social media classification and provide insights on how the use of the social media can be expanded in business to get the maximum benefits and minimize potential risks. The structure of the article fits for purpose – presents the analysis of the scientific literature, synthesis, comparison, systematization of information and its graphical visualization. The performed analysis allowed to determine possibilities for application of the social media in the enterprise activities and to identify gained benefits. Social media allows enterprises to communicate more flexible and faster both in the outside and inside environment, facilitates customer accessibility, provides opportunity to quickly respond to customer feedback or inform existing and potential customers about new ideas and proposals.

  19. A survey of social media data analysis for physical activity surveillance.

    Science.gov (United States)

    Liu, Sam; Young, Sean D

    2018-07-01

    Social media data can provide valuable information regarding people's behaviors and health outcomes. Previous studies have shown that social media data can be extracted to monitor and predict infectious disease outbreaks. These same approaches can be applied to other fields including physical activity research and forensic science. Social media data have the potential to provide real-time monitoring and prediction of physical activity level in a given region. This tool can be valuable to public health organizations as it can overcome the time lag in the reporting of physical activity epidemiology data faced by traditional research methods (e.g. surveys, observational studies). As a result, this tool could help public health organizations better mobilize and target physical activity interventions. The first part of this paper aims to describe current approaches (e.g. topic modeling, sentiment analysis and social network analysis) that could be used to analyze social media data to provide real-time monitoring of physical activity level. The second aim of this paper was to discuss ways to apply social media analysis to other fields such as forensic sciences and provide recommendations to further social media research. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  20. Laser assisted anticancer activity of benzimidazole based metal organic nanoparticles.

    Science.gov (United States)

    Praveen, P A; Ramesh Babu, R; Balaji, P; Murugadas, A; Akbarsha, M A

    2018-03-01

    Recent studies showed that the photothermal therapy can be effectively used for the targeted cancerous cells destruction. Hence, in the present study, benzimidazole based metal organic complex nanoparticles, dichloro cobalt(II) bis-benzimidazole (Co-BMZ) and dichloro copper(II) bis-benzimidazole (Cu-BMZ), were synthesized by reprecipitation method and their anti-cancer activity by means of photothermal effect has been studied. Transmission electron microscopy analysis shows that the particle size of Cu-BMZ is ∼100 nm and Co-BMZ is in the range between 100 and 400 nm. Zeta potential analysis ensures the stability of the synthesized nanoparticles. It is found that the nonlinear absorption of the nanoparticles increases with increase in laser power intensity. Phototoxicity of human lung cancer (A549) and the normal mouse embryonic fibroblast (NIH-3T3) cells was studied using a 650 nm laser. Even though both the cell lines were affected by laser irradiation, A549 cells show higher cell destruction and lower IC 50 values than the normal cells. Docking studies were used to analyse the interaction site and the results showed that the Cu-BMZ molecules have higher dock score than the Co-BMZ molecules. The obtained results indicate that Cu-BMZ samples have lesser particle size, higher nonlinear absorption and higher interaction energy than the Co-BMZ samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Effect of H-wave polarization on laser radar detection of partially convex targets in random media.

    Science.gov (United States)

    El-Ocla, Hosam

    2010-07-01

    A study on the performance of laser radar cross section (LRCS) of conducting targets with large sizes is investigated numerically in free space and random media. The LRCS is calculated using a boundary value method with beam wave incidence and H-wave polarization. Considered are those elements that contribute to the LRCS problem including random medium strength, target configuration, and beam width. The effect of the creeping waves, stimulated by H-polarization, on the LRCS behavior is manifested. Targets taking large sizes of up to five wavelengths are sufficiently larger than the beam width and are sufficient for considering fairly complex targets. Scatterers are assumed to have analytical partially convex contours with inflection points.

  2. Media use, sports activities, and motor fitness in childhood and adolescence.

    Science.gov (United States)

    Kaiser-Jovy, Sebastian; Scheu, Anja; Greier, Klaus

    2017-07-01

    Physical activity is one of the key determinants of physical, mental, and social health of children and adolescents. Therefore, the early development of health-relevant behavior patterns is of high relevance. To examine the impact of selected socioeconomic factors as well as media consumption, on sports activities and the motor skills of 10- to 14-year-old secondary school students. Body height and body weight were measured. The motor skills were determined with the Deutschen Motorik Test (DMT 6‑18; German Motor Test). Information about media use, media equipment, recreational sports activities, migration status, and the parents' profession was collected by means of a standardized questionnaire. A total of 391 adolescents have been tested (male 235; female 156). Body mass index (BMI) types are evenly distributed on gender. On a weekday, the pupils spend 10.3 h using media (SD ± 9.1 h). On weekends, media use increases up to 12 h per day on average (SD ± 9.7 h). The number of available media is independent from the age of the respondents and the social status of their families. According to bivariate correlations, heavy media use, a high BMI as well as migration status correlate negatively with both sports activities and motor skills. BMI seems to have the strongest influence on athletic performance (b = 0.41). Media use is an important determinant of juvenile sports activity and motor performance, being part of a complex juvenile leisure behavior.

  3. Developing Social Media Practices in SMEs - The Role of Distributed and Centralized Leadership Activities

    DEFF Research Database (Denmark)

    Simmelsgaard, Sonni Hansen; Lutz, Salla; Brink, Tove

    Social media practices are implemented in a growing number of B2B-companies. However, it seems that SMEs adoption of these practices is lagging behind compared with larger firms. In this context the support from the leadership is essential in order to enhance a firm’s use of social media...... for business purposes. This study aims to contribute to the scarce existing literature on leadership activities in relation to a company’s social media practices by conducting a qualitative analysis that is based on three theoretical propositions. Managerially the paper wishes to emphasize the importance...

  4. Mechanism of dark decomposition of iodine donor in the active medium of a pulsed chemical oxygen - iodine laser

    International Nuclear Information System (INIS)

    Andreeva, Tamara L; Kuznetsova, S V; Maslov, A I; Sorokin, Vadim N

    2002-01-01

    A scheme is proposed that describes the dark decomposition of iodide - the donor of iodine - and the relaxation of singlet oxygen in the chlorine-containing active medium of a pulsed chemical oxygen - iodine laser (COIL). For typical compositions of the active media of pulsed COILs utilising CH 3 I molecules as iodine donors, a branching chain reaction of the CH 3 I decomposition accompanied by the efficient dissipation of singlet oxygen is shown to develop even at the stage of filling the active volume. In the active media with CF 3 I as the donor, a similar chain reaction is retarded due to the decay of CF 3 radicals upon recombination with oxygen. The validity of this mechanism is confirmed by a rather good agreement between the results of calculations and the available experimental data. The chain decomposition of alkyliodides accompanied by an avalanche production of iodine atoms represents a new way of efficient chemical production of iodine for a COIL. (active media)

  5. High repetition rate, high energy, actively Q-switched all-in-fiber laser

    Science.gov (United States)

    Lecourt, J. B.; Bertrand, A.; Guillemet, S.; Hernandez, Y.; Giannone, D.

    2010-05-01

    We report an actively Q-switched Ytterbium-doped all-in-fibre laser delivering 10ns pulses with high repetition rate (from 100kHz to 1MHz). The laser operation has been validated at three different wavelengths (1040, 1050 and 1064nm). The laser can deliver up to 20Watts average power with an high beam quality (M2 = 1).

  6. Real-World Usage of Educational Media Does Not Promote Parent-Child Cognitive Stimulation Activities.

    Science.gov (United States)

    Choi, Jason H; Mendelsohn, Alan L; Weisleder, Adriana; Cates, Carolyn Brockmeyer; Canfield, Caitlin; Seery, Anne; Dreyer, Benard P; Tomopoulos, Suzy

    2018-03-01

    To determine whether educational media as actually used by low-income families promote parent-child cognitive stimulation activities. We performed secondary analysis of the control group of a longitudinal cohort of mother-infant dyads enrolled postpartum in an urban public hospital. Educational media exposure (via a 24-hour recall diary) and parent-child activities that may promote cognitive stimulation in the home (using StimQ) were assessed at 6, 14, 24, and 36 months. Data from 149 mother-child dyads, 93.3% Latino, were analyzed. Mean (standard deviation) educational media exposure at 6, 14, 24, and 36 months was, respectively, 25 (40), 42 (58), 39 (49), and 39 (50) minutes per day. In multilevel model analyses, prior educational media exposure had small positive relationship with subsequent total StimQ scores (β = 0.11, P = .03) but was nonsignificant (β = 0.08, P = .09) after adjusting for confounders (child: age, gender, birth order, noneducational media exposure, language; mother: age, ethnicity, marital status, country of origin, language, depressive symptoms). Educational media did predict small increases in verbal interactions and toy provision (adjusted models, respectively: β = 0.13, P = .02; β = 0.11; P = .03). In contrast, more consistent relationships were seen for models of the relationship between prior StimQ (total, verbal interactions and teaching; adjusted models, respectively: β = 0.20, P = .002; β = 0.15, P = .006; β = 0.20, P = .001) and predicted subsequent educational media. Educational media as used by this sample of low-income families does not promote cognitive stimulation activities important for early child development or activities such as reading and teaching. Copyright © 2017 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  7. LASER INDUCED SELECTIVE ACTIVATION UTILIZING AUTO-CATALYTIC ELECTROLESS PLATING ON POLYMER SURFACE

    DEFF Research Database (Denmark)

    Zhang, Yang; Nielsen, Jakob Skov; Tang, Peter Torben

    2009-01-01

    . Characterization of the deposited copper layer was used to select and improve laser parameters. Several types of polymers with different melting points were used as substrate. Using the above mentioned laser treatment, standard grades of thermoplastic materials such as ABS, SAN, PE, PC and others have been......This paper presents a new method for selective micro metallization of polymers induced by laser. An Nd: YAG laser was employed to draw patterns on polymer surfaces using a special set-up. After subsequent activation and auto-catalytic electroless plating, copper only deposited on the laser tracks....... Induced by the laser, porous and rough structures are formed on the surface, which favours the palladium attachment during the activation step prior to the metallization. Laser focus detection, scanning electron microscopy (SEM) and other instruments were used to analyze the topography of the laser track...

  8. Investigation of different liquid media and ablation times on pulsed laser ablation synthesis of aluminum nanoparticles

    International Nuclear Information System (INIS)

    Baladi, Arash; Sarraf Mamoory, Rasoul

    2010-01-01

    Aluminum nanoparticles were synthesized by pulsed laser ablation of Al targets in ethanol, acetone, and ethylene glycol. Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) images, Particle size distribution diagram from Laser Particle Size Analyzer (LPSA), UV-visible absorption spectra, and weight changes of targets were used for the characterization and comparison of products. The experiments demonstrated that ablation efficiency in ethylene glycol is too low, in ethanol is higher, and in acetone is highest. Comparison between ethanol and acetone clarified that acetone medium leads to finer nanoparticles (mean diameter of 30 nm) with narrower size distribution (from 10 to 100 nm). However, thin carbon layer coats some of them, which was not observed in ethanol medium. It was also revealed that higher ablation time resulted in higher ablated mass, but lower ablation rate. Finer nanoparticles, moreover, were synthesized in higher ablation times.

  9. Investigation of different liquid media and ablation times on pulsed laser ablation synthesis of aluminum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Baladi, Arash [Materials Engineering Department, Tarbiat Modares University, Jalal Al Ahmad, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Sarraf Mamoory, Rasoul, E-mail: rsarrafm@modares.ac.ir [Materials Engineering Department, Tarbiat Modares University, Jalal Al Ahmad, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of)

    2010-10-01

    Aluminum nanoparticles were synthesized by pulsed laser ablation of Al targets in ethanol, acetone, and ethylene glycol. Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) images, Particle size distribution diagram from Laser Particle Size Analyzer (LPSA), UV-visible absorption spectra, and weight changes of targets were used for the characterization and comparison of products. The experiments demonstrated that ablation efficiency in ethylene glycol is too low, in ethanol is higher, and in acetone is highest. Comparison between ethanol and acetone clarified that acetone medium leads to finer nanoparticles (mean diameter of 30 nm) with narrower size distribution (from 10 to 100 nm). However, thin carbon layer coats some of them, which was not observed in ethanol medium. It was also revealed that higher ablation time resulted in higher ablated mass, but lower ablation rate. Finer nanoparticles, moreover, were synthesized in higher ablation times.

  10. Social Activity, School-Related Activity, and Anti-Substance Use Media Messages on Adolescent Tobacco and Alcohol Use.

    Science.gov (United States)

    Moon, Sung Seek; Rao, Uma

    2011-01-01

    In this article, we present the effects of three hypothesized protective factors: social activities, school-related activities, and anti-substance use media messages on adolescent tobacco and alcohol use. Data were drawn from the "Monitoring the Future" (MTF) research project, which was conducted by the Institute for Social Research at the University of Michigan. The sample included 2,551 twelfth-grade students. The results of the structural equation model showed that exposure to media anti-drug messages had an indirect negative effect on tobacco and alcohol use through school-related activity and social activity. The results suggest that comprehensive ecological interventions encompassing media, family, and school can increase on the preventive effects of adolescent's substance use.

  11. Avalanche dynamics for active matter in heterogeneous media

    Science.gov (United States)

    Reichhardt, C. J. O.; Reichhardt, C.

    2018-02-01

    Using numerical simulations, we examine the dynamics of run-and-tumble disks moving in a disordered array of fixed obstacles. As a function of increasing active disk density and activity, we find a transition from a completely clogged state to a continuous flowing phase, and in the large activity limit, we observe an intermittent state where the motion occurs in avalanches that are power law distributed in size with an exponent of β =1.46. In contrast, in the thermal or low activity limit we find bursts of motion that are not broadly distributed in size. We argue that in the highly active regime, the system reaches a self-jamming state due to the activity-induced self-clustering, and that the intermittent dynamics is similar to that found in the yielding of amorphous solids. Our results show that activity is another route by which particulate systems can be tuned to a nonequilibrium critical state.

  12. From Margins to Mainstream: Social Media as a Tool for Campus Sexual Violence Activism

    Science.gov (United States)

    Linder, Chris; Myers, Jess S.; Riggle, Colleen; Lacy, Marvette

    2016-01-01

    Using Internet-related ethnography (Postill & Pink, 2012), we examined the role of social media in campus sexual violence activism. Based on observations of online activist communities and interviews with 23 activists, we highlight raising awareness, community building, and interrupting power dynamics as activism strategies enhanced by social…

  13. Modeling and analysis of laser active interference optical path

    Science.gov (United States)

    Shan, Cong-miao; Sun, Hua-yan; Zhao, Yan-zhong; Chen, Jian-biao; Ren, Jian-ying

    2017-10-01

    By using the geometrical optics and physical optics method, the models of wedge plate interference optical path, Michelson interferometer and Mach Zehnder interferometer thus three different active interference pattern are built. The optical path difference (OPD) launched by different interference patterns, fringe spacing and contrast expression have been derived. The results show that far field interference peak intensity of the wedge plate interference is small, so the detection distance is limited, Michelson interferometer with low contrast affects the performance of detection system, Mach Zehnder interferometer has greater advantages in peak intensity, the variable range of interference fringe spacing and contrast ratio. The results of this study are useful for the theoretical research and practical application of laser active interference detection.

  14. Protest, Performance and Politics: The Use of "Nano-Media" in Social Movement Activism in South Africa

    Science.gov (United States)

    Dawson, Marcelle C.

    2012-01-01

    Considering the lack of coverage in the mass media of certain kinds of social movement activity, many movements make use of smaller scale, independent media to publicise their struggles. From the vantage point of social movements in South Africa, this paper addresses what Mojca Pajnik and John Downing call "nano-media". Based on…

  15. Validity and reliability of a home environment inventory for physical activity and media equipment

    Directory of Open Access Journals (Sweden)

    Pereira Mark A

    2008-04-01

    Full Text Available Abstract Background Little is known about how the home environmental supports physical activity and screen media usage. The purpose of this study was to develop and test the reliability and validity of a self-report instrument to comprehensively reflect the availability and accessibility of physical activity and screen media equipment in the home environment. Methods Ten families participated in the initial field testing to provide feedback for instrument development. Thirty one adult participants, each of whom had at least one child 10–17 years old, completed two Physical Activity and Media Inventory (PAMI instruments. The first PAMI was completed simultaneously, but independently, with a research assistant to assess validity. A second PAMI was completed by the participant one week later to assess reliability. Results The adult participants were mostly mothers/female guardians, mean age 38 ± 7.2 years, mostly Caucasian (52%, college educated (65%, living in single family homes (74%. Test-retest reliability was acceptable to strong for all summary variables (physical activity equipment, ICC = 0.76 to 0.99; media equipment, ICC = 0.72 to 0.96. For validation, reports from participants and research assistants were strongly correlated (physical activity, 0.67 – 0.98; media, 0.79 – 0.96. Compared to participants, research assistants reported a greater percentage of physical activity equipment as "in plain view and easy to get to" and a smaller percentage of items as "put away and difficult to get to". Conclusion Our results indicate strong evidence for the reliability and validity of the variables calculated from the PAMI. This self report inventory may be useful in assessing the availability of physical activity and screen media equipment in the home environment and could be used in conjunction with other home assessment tools (food availability, parenting styles and feeding practices to identify obesogenic home environments.

  16. The Case for the Use of Active Social Media in Nonproliferation and Nuclear Security

    Energy Technology Data Exchange (ETDEWEB)

    Schanfein, Mark J.

    2015-10-05

    A great amount of attention and consideration is being directed at possible applications of social media in many challenging areas. The use of social media has already shown its importance in the area of disaster response, where, each citizen is essentially acting as a sensor in reporting local conditions. In the aggregate, valuable information is obtained to enable a more effective response as well as provide timely information to those in the disaster area. No one needs to be trained to understand what constitutes a disaster, so a social media data stream from the public is literally always active and ready to engage. A similar but more focused approach is the use of crowdsourcing for science, where specific challenges in areas such as mathematics, astronomy, and biology are posted to social media and solved by the crowd.

  17. Media Portrayals of Hashtag Activism: A Framing Analysis of Canada’s #Idlenomore Movement

    Directory of Open Access Journals (Sweden)

    Derek Moscato

    2016-04-01

    Full Text Available The confluence of activism and social media—legitimized by efforts such as the Arab Spring and Occupy Movements—represents a growing area of mainstream media focus. Using Canada’s #IdleNoMore movement as a case, this study uses framing theory to better understand how traditional media are representing activism borne of social media such as Twitter, and how such activism can ultimately have an impact in political and public policy debates. A qualitative framing analysis is used to identify frames present in media reporting of #IdleNoMore during its first two months by two prominent Canadian publications. Emergent frames show that hashtag activism as a catalyst for a social movement was embraced as a theme by one of the publications, therefore helping to legitimize the role of social media tools such as Twitter. In other frames, both positive and negative depictions of the social movement helped to identify for mainstream audiences both historical grievances and future challenges and opportunities for Canada’s First Nations communities.

  18. Management Approaches to Radical Social Media Activism: the responses of BP, HSBC and Nestlé to Greenpeace

    OpenAIRE

    Grant, Bettina

    2010-01-01

    Corporate directed radical activism has been reframed by the internet and social media, which provide radical activists with new tools to mount innovative attack forms against corporations. These attack forms (herein termed by author as radical social media activism) happen in the digital sphere and augment radical attack forms in the physical world. Corporations are challenged with a new age of radical activism and, thus far, have displayed low competence at using social media to manage this...

  19. Bacterial isolates from the bryozoan Membranipora membranacea: influence of culture media on isolation and antimicrobial activity.

    Science.gov (United States)

    Heindl, Herwig; Thiel, Vera; Wiese, Jutta; Imhoff, Johannes F

    2012-03-01

    From specimens of the bryozoan Membranipora membranacea collected in the Baltic Sea, bacteria were isolated on four different media, which significantly increased the diversity of the isolated groups. All isolates were classified according to 16S rRNA gene sequence analysis and tested for antimicrobial properties using a panel of five indicator strains and six different media. Each medium featured a unique set of isolated phylotypes, and a phylogenetically diverse collection of isolates was obtained. A total of 96 isolates were assigned to 49 phylotypes and 29 genera. Only one-third of the members of these genera had been isolated previously from comparable sources. The isolates were affiliated with Alpha- and Gammaproteobacteria, Bacilli, and Actinobacteria. A comparable large portion of up to 22 isolates, i.e., 15 phylotypes, probably represent new species. Likewise, 47 isolates (approximately 50%) displayed antibiotic activities, mostly against grampositive indicator strains. Of the active strains, 63.8 % had antibiotic traits only on one or two of the growth media, whereas only 12.7 % inhibited growth on five or all six media. The application of six different media for antimicrobial testing resulted in twice the number of positive hits as obtained with only a single medium. The use of different media for the isolation of bacteria as well as the variation of media considered suitable for the production of antibiotic substances significantly enhanced both the number of isolates obtained and the proportion of antibiotic active cultures. Thus the approach described herein offers an improved strategy in the search for new antibiotic compounds.

  20. Media multitasking is associated with distractibility and increased prefrontal activity in adolescents and young adults.

    Science.gov (United States)

    Moisala, M; Salmela, V; Hietajärvi, L; Salo, E; Carlson, S; Salonen, O; Lonka, K; Hakkarainen, K; Salmela-Aro, K; Alho, K

    2016-07-01

    The current generation of young people indulges in more media multitasking behavior (e.g., instant messaging while watching videos) in their everyday lives than older generations. Concerns have been raised about how this might affect their attentional functioning, as previous studies have indicated that extensive media multitasking in everyday life may be associated with decreased attentional control. In the current study, 149 adolescents and young adults (aged 13-24years) performed speech-listening and reading tasks that required maintaining attention in the presence of distractor stimuli in the other modality or dividing attention between two concurrent tasks. Brain activity during task performance was measured using functional magnetic resonance imaging (fMRI). We studied the relationship between self-reported daily media multitasking (MMT), task performance and brain activity during task performance. The results showed that in the presence of distractor stimuli, a higher MMT score was associated with worse performance and increased brain activity in right prefrontal regions. The level of performance during divided attention did not depend on MMT. This suggests that daily media multitasking is associated with behavioral distractibility and increased recruitment of brain areas involved in attentional and inhibitory control, and that media multitasking in everyday life does not translate to performance benefits in multitasking in laboratory settings. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. THE EFFECT OF SOCIAL MEDIA MARKETING ACTIVITIES ON BRAND AWARENESS, BRAND IMAGE AND BRAND LOYALTY

    Directory of Open Access Journals (Sweden)

    Yusuf BİLGİN

    2018-04-01

    Full Text Available The aim of this research is to examine the effect of social media marketing activities on brand awareness, brand image and brand loyalty. In addition, it has been aimed to analyze the effect of brand awareness and brand image on brand loyalty in this research. The population of the research consists of the consumers who actively follow five brands with the highest social score according to the Marketing Turkey social media brand performance data on social media communication channels such as Facebook, Twitter and Instagram. In this research, quantitative method has been used and research data has been obtained via online questionnaires shared on social media from 547 brand followers with applying convenience sampling method. The obtained data have been analyzed by structural equation modeling (SEM. As a result of the analysis, social media marketing activities have been found as effective factors on brand image and brand loyalty, besides it has been determined that the most obvious effect seen on brand awareness. In addition, it has been found out that brand awareness and brand image have a significant effect on brand loyalty. Furthermore, in the research, it has been achieved that the brand awareness has a limited effect on the brand image.

  2. Do mass media campaigns improve physical activity? a systematic review and meta-analysis.

    Science.gov (United States)

    Abioye, Ajibola I; Hajifathalian, Kaveh; Danaei, Goodarz

    2013-08-02

    Mass media campaigns are frequently used to influence the health behaviors of various populations. There are currently no quantitative meta-analyses of the effect of mass media campaigns on physical activity in adults. We searched six electronic databases from their inception to August 2012 and selected prospective studies that evaluated the effect of mass media campaigns on physical activity in adults. We excluded studies that did not have a proper control group or did not report the uncertainties of the effect estimates. Two reviewers independently screened the title/abstracts and full articles. We used random-effects models to pool effect estimates across studies for 3 selected outcomes. Nine prospective cohorts and before-after studies that followed-up 27,601 people over 8 weeks to 3 years met the inclusion criteria. Based on the pooled results from these studies, mass media campaigns had a significant effect on promoting moderate intensity walking (pooled relative risk (RR) from 3 studies=1.53, 95% Confidence Interval: 1.25 to 1.87), but did not help participants achieve sufficient levels of physical activity [4 studies pooled RR=1.02, 95% CI: 0.91 to 1.14)]. The apparent effect of media campaigns on reducing sedentary behavior (pooled RR=1.15, 95% CI: 1.03 to 1.30) was lost when a relatively low-quality study with large effects was excluded in a sensitivity analysis. In subgroup analyses, campaigns that promoted physical activity as a 'social norm' seemed to be more effective in reducing sedentary behavior. Mass media campaigns may promote walking but may not reduce sedentary behavior or lead to achieving recommended levels of overall physical activity. Further research is warranted on different campaign types and in low- and middle- income countries.

  3. Tunable radio-frequency photonic filter based on an actively mode-locked fiber laser.

    Science.gov (United States)

    Ortigosa-Blanch, A; Mora, J; Capmany, J; Ortega, B; Pastor, D

    2006-03-15

    We propose the use of an actively mode-locked fiber laser as a multitap optical source for a microwave photonic filter. The fiber laser provides multiple optical taps with an optical frequency separation equal to the external driving radio-frequency signal of the laser that governs its repetition rate. All the optical taps show equal polarization and an overall Gaussian apodization, which reduces the sidelobes. We demonstrate continuous tunability of the filter by changing the external driving radio-frequency signal of the laser, which shows good fine tunability in the operating range of the laser from 5 to 10 GHz.

  4. The study of selective emission lines from plasma, obtained by evaporating as sample by laser radiation in air and argon media

    International Nuclear Information System (INIS)

    Sufian, A.; Dimitrov, G.

    1993-01-01

    Ultra violet visible emission spectroscopic analysis of a plasma produced through laser interaction with a solid probe in different gaseous atmospheres is conducted. Reported are the effects of air and argon, as enveloping media, on the spectral intensities of some lines. The temperature gradient of the plasma, in different atmosphere, is also plotted. In order to improve the detection limits of individual elements, suggested are the possible areas of illuminating the slit of the spectroscopic from the plasma, in respect of the height, above the sample, when working in different gaseous media. (author)

  5. Actively Q-switched laser with novel Nd:YAG/YAG polygonal active-mirror

    Science.gov (United States)

    Lang, Ye; Chen, Yanzhong; Ge, Wenqi; He, Jianguo; Zhang, Hongbo; Liao, Lifen; Xin, Jianguo; Zhang, Jian; Fan, Zhongwei

    2018-03-01

    In this work, we demonstrate an efficient actively Q-switched laser based on a novel crystal Nd:YAG/YAG polygonal active mirror. A passively cooled crystal Nd:YAG/YAG polygonal active mirror with an end pump scheme was used as the gain medium. For the overlap between the TEM00 laser mode and large gain profile, a cavity was carefully designed with a large fundamental mode volume. With a maximum absorbed power of 3.1 W, a 685 mW average output power with a pulse repetition of 5 kHz was attained, and the corresponding optical-optical and slope efficiency were 22.1% and 27.7%, respectively. The pulse width was 133.9 ns. The beam quality (M 2) was 1.561 in the horizontal direction and 1.261 in the vertical direction.

  6. Laser Polarimeter for Measurement of Optical Activity of Biological Objects

    Science.gov (United States)

    Protasov, E. A.; Protasov, D. E.; Ryzhkova, A. V.

    In this paper has been described the polarimetric device for measurement of optical activity of biological tissues, where the source of radiation is an infrared laser with a wave λ=0.808 micron. The polarizers used are polarizing prisms of Glan - Taylor. To obtain required angular resolution (0.180/cm) has been developed a device that converts the angle of rotation of the analyzer into electrical signal, which is fed to the appropriate scan digital oscilloscope. The passage of the polarized light through the fingers of the hand was established and the angles of rotation of the polarization vector of the transmitted radiation were measured, the values of which may be determined by the content of hemoglobin in the blood.

  7. E-Media Use and Preferences for Physical Activity and Public Health Information: Results of a Web-Based Survey.

    Science.gov (United States)

    Jake-Schoffman, Danielle E; Wilcox, Sara; Kaczynski, Andrew T; Turner-McGrievy, Gabrielle; Friedman, Daniela B; West, Delia S

    As social media (eg, Twitter) continues to gain widespread popularity, health research and practice organizations may consider combining it with other electronic media (e-media) channels (eg, Web sites, e-newsletters) within their communication plans. However, little is known about added benefits of using social media when trying to reach public health audiences about physical activity. Learn about current use and preference for e-media communication channels among physical activity researchers and practitioners. A Web-based survey was used, open for responses from August 20, 2015, through January 5, 2016. Survey participation was voluntary and anonymous. The survey was advertised through multiple channels targeting physical activity researchers and practitioners, including announcements on professional listservs and in e-newsletters, Twitter, and posts on Facebook pages of public health organizations. A total of 284 survey respondents had complete data. Typical use of e-media to receive, seek out, and share information about physical activity and health and what appeals to researchers and practitioners for professional use. Most respondents preferred non-social media channels to social media and these preferences did not differ widely when examining subgroups such as researchers versus practitioners or social media users versus nonusers. There were few differences by respondent demographics, though younger respondents reported using social media more than older respondents. However, limiting analyses to respondents who identified as social media users, only about 1% of respondents ranked social media sources as their preferred channels for information; thus, most people would continue to be reached if communication remained largely via non-social media e-media channels. The present study supports growing evidence that careful surveying of a target audience should be undertaken when considering new communication channels, as preference and use may not support the

  8. Active solution of homography for pavement crack recovery with four laser lines.

    Science.gov (United States)

    Xu, Guan; Chen, Fang; Wu, Guangwei; Li, Xiaotao

    2018-05-08

    An active solution method of the homography, which is derived from four laser lines, is proposed to recover the pavement cracks captured by the camera to the real-dimension cracks in the pavement plane. The measurement system, including a camera and four laser projectors, captures the projection laser points on the 2D reference in different positions. The projection laser points are reconstructed in the camera coordinate system. Then, the laser lines are initialized and optimized by the projection laser points. Moreover, the plane-indicated Plücker matrices of the optimized laser lines are employed to model the laser projection points of the laser lines on the pavement. The image-pavement homography is actively determined by the solutions of the perpendicular feet of the projection laser points. The pavement cracks are recovered by the active solution of homography in the experiments. The recovery accuracy of the active solution method is verified by the 2D dimension-known reference. The test case with the measurement distance of 700 mm and the relative angle of 8° achieves the smallest recovery error of 0.78 mm in the experimental investigations, which indicates the application potentials in the vision-based pavement inspection.

  9. YouTube, Critical Pedagogy, and Media Activism

    Science.gov (United States)

    Kellner, Douglas; Kim, Gooyong

    2010-01-01

    Critical pedagogy believes education to be a form of cultural politics that is fundamental to social transformation aiming to cultivate human agency and transformative activity. The explosion of information and communication technologies (ICTs) has provided ordinary people with unprecedented opportunities to take on the ruling educational power…

  10. Adherence to active play and electronic media guidelines in preschool children: gender and parental education considerations.

    Science.gov (United States)

    Loprinzi, Paul D; Schary, David P; Cardinal, Bradley J

    2013-01-01

    The primary purpose of the present study was to examine adherence to current active play and electronic media use guidelines in a sample of US preschool-aged children and to examine whether differences occurred across gender and parental education. 164 parents completed an on-line survey to estimate preschool children's active play and sedentary behaviors. For weekdays, 50% of the sample met the active play guideline with this increasing to 65% during the weekend. With respect to electronic media use, 90% of the sample met guidelines during the week, with the percentage meeting guidelines dropping to 78% during the weekend. A greater percentage of preschool children from high parental education families (83.4 ± 3.3) met electronic media use guidelines on the weekends, compared to preschool children from low parental education families (59.4 ± 8.1) (p = 0.002). Our findings indicate that a substantial portion of preschool children are not meeting active play guidelines and that adherence to active play and electronic media use guidelines may be influenced by parental education.

  11. The influence of wanting to look like media figures on adolescent physical activity.

    Science.gov (United States)

    Taveras, Elsie M; Rifas-Shiman, Sheryl L; Field, Alison E; Frazier, A Lindsay; Colditz, Graham A; Gillman, Matthew W

    2004-07-01

    To examine the association of adolescents' wanting to look like figures in the media with physical activity levels. Cross-sectional mailed survey of 11,606 boys and girls, between the ages of 9 and 16 years, participating in the Growing Up Today Study in 1997. Participants reported detailed information on physical activities over the previous year, and the degree to which they were trying to look like same-sex images in television, movies, and magazines. We performed linear regression modeling to assess the independent effects of wanting to look like figures in the media on physical activity levels. Mean total weekly physical activity levels were 12.4 hours in girls and 15.2 hours in boys. 3019 (46%) girls and 1360 (27%) boys reported making at least some effort to look like figures in the media. Adjusted for age, body mass index, sexual maturity rating, and race/ethnicity, total physical activity levels were higher by 0.7 (95% CI 0.5-0.9) and 1.2 (95% CI 0.9-1.6) hours per week in girls and boys, respectively, for every 1 (out of 5) category increase in wanting to look like figures in the media. Adjustment for intrapersonal and social confounders modestly attenuated the associations. Wanting to look like figures in the media was associated with higher physical activity levels among older children and adolescents, independent of other personal and social influences. These data suggest that television, movie, and magazine industries should be encouraged to cultivate and reinforce realistic and healthy norms of physical activity and body image.

  12. Microbiological profile from middle ear and nasopharynx in patients suffering from chronic active mucosal otitis media

    International Nuclear Information System (INIS)

    Khattak, S.F.; Sheikh, N.A.; Aleem, A.; Farooq, M.; Nadeem, K.

    2017-01-01

    Chronic otitis media is described as a tympanic membrane perforation and ear discharge for more than six weeks duration. Ascending infection from the nasopharynx into the middle ear cleft has been attributed to prevent resolution of chronic otitis media. This research aims to determine the association between the microbiological flora of the nasopharynx with that of the middle ear in patients suffering from chronic (active) mucosal otitis media. Methods: Our study is a hospital-based cross-sectional survey. It was conducted from December 2015 to February 2017 at the Department of ENT, Combined Military Hospital, Abbottabad. Ear and nasopharyngeal swabs were obtained from 65 patients of chronic active mucosal otitis media and sent for microbiological analysis. Microbiological culture and sensitivity test was performed to identify the microbial spectrum of each specimen. Performa bearing the result of otoscopy, aspirate and swabs were completed for middle ear and the nasopharyngeal culture with reference to each patient. Descriptive statistics and Pearson's chi square analysis were performed using SPSS-22. Results: Staphylococcus aureus and Pseudomonas aeruginosa are foremost micro-organisms found in otorrhea culture isolated from patients of chronic active mucosal otitis media. Majority of the cultures from nasopharynx of these patients did not reveal any growth after incubation for 48 hours. Conclusion: A statistically insignificant association exists between the microbiological spectrum of the middle ear and the nasopharynx of patients suffering from chronic active mucosal otitis media. Micro organisms' exposure from a perforated tympanic membrane remains leading cause of persistent otorrhea, rather than ascending infection through the Eustachian tube. (author)

  13. Kinetics of Thermally Activated Physical Processes in Disordered Media

    Directory of Open Access Journals (Sweden)

    Bertrand Poumellec

    2015-07-01

    Full Text Available We describe a framework for modeling the writing and erasure of thermally-distributed activated processes that we can specifically apply to UV-induced refractive index change, particularly in fibers. From experimental measurements (isochrons and/or isotherms, this framework allows to find the distribution function of the activation energy by providing only a constant, which can be determined by a simple variable change when a few assumptions are fulfilled. From this modeling, it is possible to know the complete evolution in time of the system. It is also possible to determine the annealing conditions for extending a lifetime. This approach can also be used for other physical quantities, such as photodarkening, stress relaxation, and luminescence decay, provided that it can be described by a distribution function.

  14. Polarization ray tracing in anisotropic optically active media. II. Theory and physics

    International Nuclear Information System (INIS)

    McClain, S.C.; Hillman, L.W.; Chipman, R.A.

    1993-01-01

    Refraction, reflection, and amplitude relations are derived that apply to polarization ray tracing in anisotropic, optically active media such as quartz. The constitutive relations for quartz are discussed. The refractive indices and polarization states associated with the two modes of propagation are derived as a function of wave direction. A procedure for refracting at any uniaxial or optically active interface is derived that computes both the ray direction and the wave direction. A method for computing the optical path length is given, and Fresnel transmission and ref lection equations are derived from boundary conditions on the electromagnetic fields. These ray-tracing formulas apply to uniaxial, optically active media and therefore encompass uniaxial, non-optically active materials and isotropic, optically active materials

  15. Methanogenic activity tests by Infrared Tunable Diode Laser Absorption Spectroscopy.

    Science.gov (United States)

    Martinez-Cruz, Karla; Sepulveda-Jauregui, Armando; Escobar-Orozco, Nayeli; Thalasso, Frederic

    2012-10-01

    Methanogenic activity (MA) tests are commonly carried out to estimate the capability of anaerobic biomass to treat effluents, to evaluate anaerobic activity in bioreactors or natural ecosystems, or to quantify inhibitory effects on methanogenic activity. These activity tests are usually based on the measurement of the volume of biogas produced by volumetric, pressure increase or gas chromatography (GC) methods. In this study, we present an alternative method for non-invasive measurement of methane produced during activity tests in closed vials, based on Infrared Tunable Diode Laser Absorption Spectroscopy (MA-TDLAS). This new method was tested during model acetoclastic and hydrogenotrophic methanogenic activity tests and was compared to a more traditional method based on gas chromatography. From the results obtained, the CH(4) detection limit of the method was estimated to 60 ppm and the minimum measurable methane production rate was estimated to 1.09(.)10(-3) mg l(-1) h(-1), which is below CH(4) production rate usually reported in both anaerobic reactors and natural ecosystems. Additionally to sensitivity, the method has several potential interests compared to more traditional methods among which short measurements time allowing the measurement of a large number of MA test vials, non-invasive measurements avoiding leakage or external interferences and similar cost to GC based methods. It is concluded that MA-TDLAS is a promising method that could be of interest not only in the field of anaerobic digestion but also, in the field of environmental ecology where CH(4) production rates are usually very low. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Activation of platelets by low-osmolar contrast media: differential effects of ionic and nonionic agents

    NARCIS (Netherlands)

    Hardeman, M. R.; Konijnenberg, A.; Sturk, A.; Reekers, J. A.

    1994-01-01

    To determine the effects of an ionic low-osmolar contrast medium (ioxaglate) and two nonionic low-osmolar contrast media (iohexol and iopamidol) on human platelet activation in vitro. Flow cytometry analysis subsequent to reaction with fluorescence-labeled monoclonal antibodies was used to detect

  17. Thai Youths and Global Warming: Media Information, Awareness, and Lifestyle Activities

    Science.gov (United States)

    Chokriensukchai, Kanchana; Tamang, Ritendra

    2010-01-01

    This study examines the exposure of Thai youths to media information on global warming, the relationship between exposure to global warming information and awareness of global warming, and the relationship between that awareness and lifestyle activities that contribute to global warming. A focus group of eight Thai youths provided information that…

  18. Organic liquids as ''activ media'' in a holographic ionizing radiation dosimeter

    International Nuclear Information System (INIS)

    Nicolau-Rebigan, S.

    1979-01-01

    Some types of organic liquids for using as activ media in a holographic ionizing radiation dosimeter are presented. One outlined the advantages of the holographic dosimeter comparatively with those of common used dosimeters. One presented the advantages of utilization of the organic liquids comparatively with another chemical systems used in a holographic ionizing radiation dosimeter. (author)

  19. Brain activation upon ideal-body media exposure and peer feedback in adolescent girls

    NARCIS (Netherlands)

    Veldhuis, J.; van der Meulen, Mara; Braams, Barbara; Peters, Sabine; Konijn, E.A.; Crone, Eveline A.

    2017-01-01

    Media’s prevailing thin-body ideal plays a vital role in adolescent girls’ body image development, but the co-occurring impact of peer feedback is understudied. The present study used functional Magnetic Resonance Imaging (fMRI) to test media imagery and peer feedback combinations on neural activity

  20. Pair Interaction of Catalytical Sphere Dimers in Chemically Active Media

    Directory of Open Access Journals (Sweden)

    Jing-Min Shi

    2018-01-01

    Full Text Available We study the pair dynamics of two self-propelled sphere dimers in the chemically active medium in which a cubic autocatalytic chemical reaction takes place. Concentration gradient around the dimer, created by reactions occurring on the catalytic sphere surface and responsible for the self-propulsion, is greatly influenced by the chemical activities of the environment. Consequently, the pair dynamics of two dimers mediated by the concentration field are affected. In the particle-based mesoscopic simulation, we combine molecular dynamics (MD for potential interactions and reactive multiparticle collision dynamics (RMPC for solvent flow and bulk reactions. Our results indicate three different configurations between a pair of dimers after the collision, i.e., two possible scenarios of bound dimer pairs and one unbound dimer pair. A phase diagram is sketched as a function of the rate coefficients of the environment reactions. Since the pair interactions are the basic elements of larger scale systems, we believe the results may shed light on the understanding of the collective dynamics.

  1. Novel design of low-jitter 10 GHz all-active monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Christiansen, Lotte Jin

    2004-01-01

    Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared.......Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared....

  2. Active stabilization of a rapidly chirped laser by an optoelectronic digital servo-loop control.

    Science.gov (United States)

    Gorju, G; Jucha, A; Jain, A; Crozatier, V; Lorgeré, I; Le Gouët, J-L; Bretenaker, F; Colice, M

    2007-03-01

    We propose and demonstrate a novel active stabilization scheme for wide and fast frequency chirps. The system measures the laser instantaneous frequency deviation from a perfectly linear chirp, thanks to a digital phase detection process, and provides an error signal that is used to servo-loop control the chirped laser. This way, the frequency errors affecting a laser scan over 10 GHz on the millisecond timescale are drastically reduced below 100 kHz. This active optoelectronic digital servo-loop control opens new and interesting perspectives in fields where rapidly chirped lasers are crucial.

  3. Adolescents' physical activity: competition between perceived neighborhood sport facilities and home media resources.

    Science.gov (United States)

    Wong, Bonny Yee-Man; Cerin, Ester; Ho, Sai-Yin; Mak, Kwok-Kei; Lo, Wing-Sze; Lam, Tai-Hing

    2010-04-01

    To examine the independent, competing, and interactive effects of perceived availability of specific types of media in the home and neighborhood sport facilities on adolescents' leisure-time physical activity (PA). Survey data from 34 369 students in 42 Hong Kong secondary schools were collected (2006-07). Respondents reported moderate-to-vigorous leisure-time PA, presence of sport facilities in the neighborhood and of media equipment in the home. Being sufficiently physically active was defined as engaging in at least 30 minutes of non-school leisure-time PA on a daily basis. Logistic regression and post-estimation linear combinations of regression coefficients were used to examine the independent and competing effects of sport facilities and media equipment on leisure-time PA. Perceived availability of sport facilities was positively (OR(boys) = 1.17; OR(girls) = 1.26), and that of computer/Internet negatively (OR(boys) = 0.48; OR(girls) = 0.41), associated with being sufficiently active. A significant positive association between video game console and being sufficiently active was found in girls (OR(girls) = 1.19) but not in boys. Compared with adolescents without sport facilities and media equipment, those who reported sport facilities only were more likely to be physically active (OR(boys) = 1.26; OR(girls) = 1.34), while those who additionally reported computer/Internet were less likely to be physically active (OR(boys) = 0.60; OR(girls) = 0.54). Perceived availability of sport facilities in the neighborhood may positively impact on adolescents' level of physical activity. However, having computer/Internet may cancel out the effects of active opportunities in the neighborhood. This suggests that physical activity programs for adolescents need to consider limiting the access to computer-mediated communication as an important intervention component.

  4. Fibrinolytic activity is associated with presence of cystic media degeneration in aneurysms of the ascending aorta

    OpenAIRE

    Borges , Luciano F; Gomez , Delphine; Quintana , Mercedes; Leclercq , Anne; Touat , Ziad; Jondeau , Guillaume; Meilhac , Olivier; Jandrot-Perrus , Martine; Gutierrez , Paulo Sampaio; Freymuller , Edna; Vranckx , Roger; Michel , Jean-Baptiste

    2010-01-01

    Abstract Aims Thoracic Ascending Aortic Aneurysms (TAA) are characterized by elastic fibre breakdown and cystic medial degeneration within the aortic media, associated with progressive SMC rarefaction. The TGF-?/Smad2 signaling pathway is involved in this process. Since pericellular fibrinolytic system activation is able to degrade adhesive proteins, activate MMPs, induce SMC disappearance and increase the bio-availability of TGF-?, we explored the plasminergic system in TAA. ...

  5. Aspects on Media Self Regulation Reflected in the Activity of Romanian Journalists

    Directory of Open Access Journals (Sweden)

    Daniela Aurelia Popa

    2011-05-01

    Full Text Available The media organizations in Romania, reticent to the idea to constraint the press freedom, manage to understand the importance of implementing a system of media responsibility. Therefore, the present study is a research in incipient stage that begins with the identification of the initiatives of media self regulation as an alternative to the efforts of enacting press in Romania. The identification of the self regulating system in Romania will be accomplished through the description of the context of development of the media responsibility system in the Romanian journalistic culture and by underlining the self regulation initiatives. For the delineation and establishment of such important self regulation initiatives, the activity of an ethical instance is necessary, for the defense and solving cases of norms contained by the new deontological code. The establishment of such an instance in Romania will represent a viable solution for the development of a more ethical professional environment that confirms the assumption of media responsibility for the adhesion to quality journalistic standards.

  6. Lasers

    CERN Document Server

    Milonni, Peter W

    1988-01-01

    A comprehensive introduction to the operating principles and applications of lasers. Explains basic principles, including the necessary elements of classical and quantum physics. Provides concise discussions of various laser types including gas, solid state, semiconductor, and free electron lasers, as well as of laser resonators, diffraction, optical coherence, and many applications including holography, phase conjugation, wave mixing, and nonlinear optics. Incorporates many intuitive explanations and practical examples. Discussions are self-contained in a consistent notation and in a style that should appeal to physicists, chemists, optical scientists and engineers.

  7. Modulation doping of quantum dot laser active area and its impact on lasing performance

    Science.gov (United States)

    Konoplev, S. S.; Savelyev, A. V.; Korenev, V. V.; Maximov, M. V.; Zhukov, A. E.

    2015-11-01

    We present a theoretical study of modulation doping of active region in the quantum dot (QD) laser and corresponding issues of QD charge neutrality violation, a band diagram of the laser and charge carriers distribution in the structure. Modulation doping is discussed as a possible technique to control laser output characteristics. It was shown that modulation doping leads to an increase of threshold current of lasing through excited QD optical transition together with power emission from QD ground state.

  8. Modulation doping of quantum dot laser active area and its impact on lasing performance

    International Nuclear Information System (INIS)

    Konoplev, S S; Savelyev, A V; Korenev, V V; Maximov, M V; Zhukov, A E

    2015-01-01

    We present a theoretical study of modulation doping of active region in the quantum dot (QD) laser and corresponding issues of QD charge neutrality violation, a band diagram of the laser and charge carriers distribution in the structure. Modulation doping is discussed as a possible technique to control laser output characteristics. It was shown that modulation doping leads to an increase of threshold current of lasing through excited QD optical transition together with power emission from QD ground state. (paper)

  9. Metal halides vapor lasers with inner reactor and small active volume.

    Science.gov (United States)

    Shiyanov, D. V.; Sukhanov, V. B.; Evtushenko, G. S.

    2018-04-01

    Investigation of the energy characteristics of copper, manganese, lead halide vapor lasers with inner reactor and small active volume 90 cm3 was made. The optimal operating pulse repetition rates, temperatures, and buffer gas pressure for gas discharge tubes with internal and external electrodes are determined. Under identical pump conditions, such systems are not inferior in their characteristics to standard metal halide vapor lasers. It is shown that the use of a zeolite halogen generator provides lifetime laser operation.

  10. Laser-activated protein solder for peripheral nerve repair

    Science.gov (United States)

    Trickett, Rodney I.; Lauto, Antonio; Dawes, Judith M.; Owen, Earl R.

    1995-05-01

    A 100 micrometers core optical fiber-coupled 75 mW diode laser operating at a wavelength of 800 nm has been used in conjunction with a protein solder to stripe weld severed rat tibial nerves, reducing the long operating time required for microsurgical nerve repair. Welding is produced by selective laser denaturation of the albumin based solder which contains the dye indocyanine green. Operating time for laser soldering was 10 +/- 5 min. (n equals 20) compared to 23 +/- 9 min. (n equals 10) for microsuturing. The laser solder technique resulted in patent welds with a tensile strength of 15 +/- 5 g, while microsutured nerves had a tensile strength of 40 +/- 10 g. Histopathology of the laser soldered nerves, conducted immediately after surgery, displayed solder adhesion to the outer membrane with minimal damage to the inner axons of the nerves. An in vivo study is under way comparing laser solder repaired tibial nerves to conventional microsuture repair. At the time of submission 15 laser soldered nerves and 7 sutured nerves were characterized at 3 months and showed successful regeneration with compound muscle action potentials of 27 +/- 8 mV and 29 +/- 8 mW respectively. A faster, less damaging and long lasting laser based anastomotic technique is presented.

  11. Active stabilization of a diode laser injection lock.

    Science.gov (United States)

    Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep

    2016-06-01

    We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.

  12. Active manipulation of the selective alignment by two laser pulses

    International Nuclear Information System (INIS)

    Zeng-Qiang, Yang; Zhi-Rong, Guo; Gui-Xian, Ge

    2010-01-01

    This paper solves numerically the full time-dependent Schrödinger equation based on the rigid rotor model, and proposes a novel strategy to determine the optimal time delay of the two laser pulses to manipulate the molecular selective alignment. The results illustrate that the molecular alignment generated by the first pulse can be suppressed or enhanced selectively, the relative populations of even and odd rotational states in the final rotational wave packet can be manipulated selectively by precisely inserting the peak of the second laser pulse at the time when the slope for the alignment parameter by the first laser locates a local maximum for the even rotational states and a local minimum for the odds, and vice versa. The selective alignment can be further optimised by selecting the intensity ratio of the two laser pulses on the condition that the total laser intensity and pulse duration are kept constant. (atomic and molecular physics)

  13. HF laser

    International Nuclear Information System (INIS)

    Suzuki, Kazuya; Iwasaki, Matae

    1977-01-01

    A review is made of the research and development of HF chemical laser and its related work. Many gaseous compounds are used as laser media successfully; reaction kinetics and technological problems are described. The hybrid chemical laser of HF-CO 2 system and the topics related to the isotope separation are also included. (auth.)

  14. Brain activation upon ideal-body media exposure and peer feedback in late adolescent girls.

    Science.gov (United States)

    van der Meulen, Mara; Veldhuis, Jolanda; Braams, Barbara R; Peters, Sabine; Konijn, Elly A; Crone, Eveline A

    2017-08-01

    Media's prevailing thin-body ideal plays a vital role in adolescent girls' body image development, but the co-occurring impact of peer feedback is understudied. The present study used functional magnetic resonance imaging (fMRI) to test media imagery and peer feedback combinations on neural activity related to thin-body ideals. Twenty-four healthy female late adolescents rated precategorized body sizes of bikini models (too thin or normal), directly followed by ostensible peer feedback (too thin or normal). Consistent with prior studies on social feedback processing, results showed increased brain activity in the dorsal medial prefrontal cortex (dmPFC)/anterior cingulate cortex (ACC) and bilateral insula in incongruent situations: when participants rated media models' body size as normal while peer feedback indicated the models as too thin (or vice versa). This effect was stronger for girls with lower self-esteem. A subsequent behavioral study (N = 34 female late adolescents, separate sample) demonstrated that participants changed behavior in the direction of the peer feedback: precategorized normal sized models were rated as too thin more often after receiving too thin peer feedback. This suggests that the neural responses upon peer feedback may influence subsequent choice. Our results show that media-by-peer interactions have pronounced effects on girls' body ideals.

  15. Active Interrogation of Sensitive Nuclear Material Using Laser Driven Neutron Beams

    International Nuclear Information System (INIS)

    Favalli, Andrea; Roth, Markus

    2015-01-01

    An investigation of the viability of a laser-driven neutron source for active interrogation is reported. The need is for a fast, movable, operationally safe neutron source which is energy tunable and has high-intensity, directional neutron production. Reasons for the choice of neutrons and lasers are set forth. Results from the interrogation of an enriched U sample are shown.

  16. Laser-activated solid protein bands for peripheral nerve repair: an vivo study.

    Science.gov (United States)

    Lauto, A; Trickett, R; Malik, R; Dawes, J M; Owen, E R

    1997-01-01

    Severed tibial nerves in rats were repaired using a novel technique, utilizing a semiconductor diode-laser-activated protein solder applied longitudinally across the join. Welding was produced by selective laser denaturation of solid solder bands containing the dye indocyanine green. An in vivo study, using 48 adult male Wistar rats, compared conventional microsuture-repaired tibial nerves with laser solder-repaired nerves. Nerve repairs were characterised immediately after surgery and after 3 months. Successful regeneration with average compound muscle action potentials of 2.5 +/- 0.5 mV and 2.7 +/- 0.3 mV (mean and standard deviation) was demonstrated for the laser-soldered nerves and the sutured nerves, respectively. Histopathology confirmed comparable regeneration of axons in laser- and suture-operated nerves. The laser-based nerve repair technique was easier and faster than microsuture repair, minimising manipulation damage to the nerve.

  17. Active mode locking of quantum cascade lasers in an external ring cavity.

    Science.gov (United States)

    Revin, D G; Hemingway, M; Wang, Y; Cockburn, J W; Belyanin, A

    2016-05-05

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode-locked operation remains a challenge, despite dedicated effort. Here we report the demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents.

  18. Laser-activated protein bands for peripheral nerve repair

    Science.gov (United States)

    Lauto, Antonio; Trickett, Rodney I.; Malik, Richard; Dawes, Judith M.; Owen, Earl R.

    1996-01-01

    A 100 micrometer core optical fiber-coupled 75 mW diode laser operating at a wavelength of 800 nm has been used in conjunction with a protein solder to stripe weld severed rat tibial nerves, reducing the long operating time required for microsurgical nerve repair. Welding is produced by selective laser denaturation of the protein based solder which contains the dye indocyanine green. Operating time for laser soldering was 10 plus or minus 5 min. (n equals 24) compared to 23 plus or minus 9 min (n equals 13) for microsuturing. The laser solder technique resulted in patent welds with a tensile strength of 15 plus or minus 5 g, while microsutured nerves had a tensile strength of 40 plus or minus 10 g. Histopathology of the laser soldered nerves, conducted immediately after surgery, displayed solder adhesion to the outer membrane with minimal damage to the inner axons of the nerves. An in vivo study, with a total of fifty-seven adult male wistar rats, compared laser solder repaired tibial nerves to conventional microsuture repair. Twenty-four laser soldered nerves and thirteen sutured nerves were characterized at three months and showed successful regeneration with average compound muscle action potentials (CMAP) of 2.4 plus or minus 0.7 mV and 2.7 plus or minus 0.8 mV respectively. Histopathology of the in vivo study, confirmed the comparable regeneration of axons in laser and suture operated nerves. A faster, less damaging and long lasting laser based anastomotic technique is presented.

  19. Communicative Informatics: An Active and Creative Audience Framework of Social Media

    Directory of Open Access Journals (Sweden)

    Linda M. Gallant

    2011-09-01

    Full Text Available Communicative informatics reflects the interactive complexity of web-based communication and a paradigm shift away from mass communication. Three discursive spheres (database and information systems, human computer interaction, and active audiences work together to control online communication openness and its consequences for post-mass media society’s public common. This has implications for communication freedom, creativity, and constraints in an information-based society. Four propositions shed light on how online audience activity is encouraged by and imperative to corporate interests; how audience creativity can create, accept, or reject messages; how the online audience is monitored; and how online rhetoric can produce or inhibit public commons. Evidence shows that social media’s corporate interests can be at odds with online privacy and citizen communication. This tension is explored with a unique focus on rhetoric, argument, and the communication between audience members and Internet-based corporate media by way of digitized communication feedback loops.

  20. Recent Cooperative Research Activities of HDD and Flexible Media Transport Technologies in Japan

    Science.gov (United States)

    Ono, Kyosuke

    This paper presents the recent status of industry-university cooperative research activities in Japan on the mechatronics of information storage and input/output equipment. There are three research committees for promoting information exchange on technical problems and research topics of head-disk interface in hard disk drives (HDD), flexible media transport and image printing processes which are supported by the Japan Society of Mechanical Engineering (JSME), the Japanese Society of Tribologists (JAST) and the Japan Society of Precision Engineering (JSPE). For hard disk drive technology, the Storage Research Consortium (SRC) is supporting more than 40 research groups in various different universities to perform basic research for future HDD technology. The past and present statuses of these activities are introduced, particularly focusing on HDD and flexible media transport mechanisms.

  1. Active stabilization of a diode laser injection lock

    Energy Technology Data Exchange (ETDEWEB)

    Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep [Department of Physics, University of Washington, P.O. Box 351560, Seattle, Washington 98195-1560 (United States)

    2016-06-15

    We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser’s transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.

  2. Active stabilization of a diode laser injection lock

    International Nuclear Information System (INIS)

    Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep

    2016-01-01

    We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser’s transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudden failures such as temporary occlusion of the injection beam. We demonstrate the successful performance of our stabilization method in a diode laser setup at 399 nm used for laser cooling of Yb atoms. The device eases the requirements on passive stabilization and can benefit any diode laser injection lock application, particularly those where several such locks are employed.

  3. Determine small and medium enterprise social media activities: A community engagement project in the Tshwane community

    OpenAIRE

    Louise van Scheers; Jacques van Scheers

    2015-01-01

    The aim of this paper is to determine small and medium enterprise (SME) social media activities and promote CE scholarship engagement. It is a community engagement project conducted in the Tshwane community. Community engagement (CE) as a planned process with the specific purpose of working with identified groups of people in the community to address issues affecting their well-being. The CE project SME skills transfer workshops are aimed at expanding involvement with the community. The benef...

  4. Moral Disengagement in media and Moral Identity activation: their interactive effect on support of war

    OpenAIRE

    Liebnitzky, Jan

    2015-01-01

    People can disengage from their internalized moral standards and self-regulation in order to perform immoral behaviour by using different Moral Disengagement mechanisms. These mechanisms within media have a positive effect on immoral behaviour. However, Moral Identity activation is said to counter arguments of Moral Disengagement. In this study, both concepts are applied to the context of war. An additional assumption took into account in how far participants’ internalized moral standards con...

  5. On nature of spontaneous elongation of polymers preliminarily stretched in adsorption-active media under irradiation

    International Nuclear Information System (INIS)

    Sinevich, E.A.; Prazdnichnyj, A.M.; Tikhomirov, V.S.; Bakeev, N.F.

    1989-01-01

    The nature of the spontaneous elongation under irradiation with fast electrons of polymers preliminary stretched in adsorption-active media has been studied. This effect is related with radiation-induced heating of microporous polymer samples. Its manifestation in amorphous PETP requires the presence of crazes having well developed microfibrillar structure. The spontaneous elongation effect is shown to be a result of crystallization of partially oriented material in transitional regions relating the oriented material of microfibrils inside crazes with nonstrained polymer between them

  6. Phatic Culture and the Status Quo: Reconsidering the Purpose of Social Media Activism

    OpenAIRE

    Miller, Vincent

    2015-01-01

    Apart from the exchanging of information, an important role of conversation and communication is to promote social harmony through the maintenance of relationships. This is referred to as the ‘phatic’ function of communication. Indeed, digital communications technologies, and social media in particular, have been lauded for their potential to promote activism and social change through ‘raising awareness’ of injustices, their ability to motivate people into political action, and the facility t...

  7. Active Stabilization of a Diode Laser Injection Lock

    OpenAIRE

    Saxberg, Brendan; Plotkin-Swing, Benjamin; Gupta, Subhadeep

    2016-01-01

    We report on a device to electronically stabilize the optical injection lock of a semiconductor diode laser. Our technique uses as discriminator the peak height of the laser's transmission signal on a scanning Fabry-Perot cavity and feeds back to the diode current, thereby maintaining maximum optical power in the injected mode. A two-component feedback algorithm provides constant optimization of the injection lock, keeping it robust to slow thermal drifts and allowing fast recovery from sudde...

  8. Determine small and medium enterprise social media activities: A community engagement project in the Tshwane community

    Directory of Open Access Journals (Sweden)

    Louise van Scheers

    2015-09-01

    Full Text Available The aim of this paper is to determine small and medium enterprise (SME social media activities and promote CE scholarship engagement. It is a community engagement project conducted in the Tshwane community. Community engagement (CE as a planned process with the specific purpose of working with identified groups of people in the community to address issues affecting their well-being. The CE project SME skills transfer workshops are aimed at expanding involvement with the community. The benefits of social media seem to be ignored by most SMEs however; challenges prevent SME owners from using the tool effectively. A survey study method of research design has been selected for the research. The sample for the study comprised 200 SME owners who currently manage small businesses in the Tshwane area. The conducted research recommends that social media can be cost effective if the SMEs make use of their social networks and use best practises that enable them to get their adverts or posts shared across social networks. The conducted research also recommends that SMEs with limited resources start with social media and YouTube as a marketing tool, as the learning curve is low and cost involved is almost nil.

  9. Influence factors of photocatalytic activity of the filter media modified by TiO2

    Directory of Open Access Journals (Sweden)

    Shen Rongyan

    2014-01-01

    Full Text Available The gangue filter media was modified by the titanium dioxide (TiO2 through the liquid phase deposition method. Some influence factors of photocatalytic activity were investigated, including the mole ratio of initial solution, the water bath temperature, the deposition time, the calcination temperature, and the heat preservation time of calcination. The morphology of the film was examined by SEM, EDS, and crystallite structure by X-Ray Diffraction (XRD. The SEM, EDS, and XRD data showed that new TiO2 crystal was found in the modified filter media. And the specific surface area of the modified filter media greatly increased. By the orthogonal experiment, the optimum parameters of modification were (NH42TiF6:H3BO3=1:2, water bath temperature of 80ºC, deposition time of 5h, calcination temperature of 500ºC, and 1h heat preservation time of calcination. Under above conditions, the heavy nitrogen wastewater of 1589.94 mg/L COD and 18750 times chroma was treated by the modified filter media. After 1h catalytic reaction, the decolorization rate and COD removal rate reached 65.89% and 47.87%, respectively.

  10. Interactions between iodinated contrast media and tissue plasminogen activator: In vitro comparison study.

    Science.gov (United States)

    Vörös, Eszter; Deres, László; Halmosi, Róbert; Várady, Edit; Tóth, Kálmán; Battyáni, István

    2017-01-01

    Iodinated contrast media (Xenetix®, Ultravist®, Omnipaque®, Visipaque® and Iomeron®) used for computed tomography (CT) may decrease fibrinolysis by recombinant tissue plasminogen activator (rt-PA). We hypothesized that receiving iodinated contrast media before rt-PA may impair thrombolysis as measured by a new model system. Whole blood from Wistar Kyoto rats (n = 10) was obtained and allowed to form blood clots. Thrombolysis was performed by placing individually the prepared clots into 15 mL tubes and adding 5 mL saline buffer, 100μg rt-PA and a different contrast media; adjusting the quantity of iodine to either 30 mg or 60 mg. The thrombolytic efficacy was quantified by measuring the optical density (OD415) of the supernatant at different time points, namely at 0, 30, 60, and 90 min. There was a significant decrease in clot lysis efficiency observed in presence of iodine containing contrast media comparing to positive control group. Moreover, when the quantity of iodine was increased from 30 mg to 60 mg; the dissolution rate downturned with additional ∼50%. In conclusion, our study suggests that high dose of iodine potentially could negatively affect the efficiency of the thrombolytic therapy performed by rt-PA.

  11. Media Education Initiatives by Media Organizations: The Uses of Media Literacy in Hong Kong Media

    Science.gov (United States)

    Chu, Donna; Lee, Alice Y. L.

    2014-01-01

    As more media organizations have engaged in media education, this paper investigates the goals and practices of these activities. This article coins media education initiatives by media organizations with the term "media-organization media literac"y (MOML). Four MOML projects in Hong Kong were selected for examination. Built on critical…

  12. Becoming a Youth Activist in the Internet Age: A Case Study on Social Media Activism and Identity Development

    Science.gov (United States)

    Fullam, Jordan

    2017-01-01

    This paper draws on a case study of one youth activist, and explores connections between social media activism, identity development, and critical education. Justin Rodriguez, a 17-year-old high school student in Newark, New Jersey, leveraged social media and texting as organizing tools and garnered support for a school walkout to protest…

  13. Fetoscopic laser coagulation of intertwin anastomoses reduces discordant placental autophagic activities in discordant twin growth

    Directory of Open Access Journals (Sweden)

    Yao-Lung Chang

    2015-10-01

    Conclusion: The discordance of placenta autophagic activity in the monochorionic twin with sIUGR was reduced after laser coagulation of the intertwin anastomoses, which may result from the effect of correction of the discordant intertwin placenta perfusion.

  14. On the analysis of the activation mechanisms of sub-melt laser anneals

    DEFF Research Database (Denmark)

    Clarysse, T.; Bogdanowicz, J.; Goosens, J.

    2008-01-01

    electrically active concentration level as well as the concurrent mobility is dependent on the dopant concentration level. This implies that the activation of B through the laser anneal process in the explored temperature–time space is governed by kinetic processes (i.e. the dissolution of B–I pairs......In order to fabricate carrier profiles with a junction depth (15 nm) and sheet resistance value suited for sub-32 nm Si-CMOS technology, the usage of sub-melt laser anneal is a promising route to explore. As laser annealed junctions seem to outperform standard anneal approaches, a detailed......) and not by the (temperature related) solid solubility....

  15. Influence of Atmospheric Propagation on Performance of Laser Active Imaging System

    International Nuclear Information System (INIS)

    Li Yingchun; Sun Huayan; Guo Huichao; Zhao Yun

    2011-01-01

    Atmospheric propagation has serious influence on the performance of a good designed laser active imaging system. Atmospheric attenuation and turbulence are two main effects on laser atmospheric propagation. Imaging SNR (Signal-Noise-Ratio) and resolution are two key indexes to describe the performance of a laser active imaging system. Establishing the relation between system performance index and atmospheric propagation effect is significant. The paper analyzed the relation between imaging performance and atmospheric attenuation and turbulence through simulation. And also the experiments were done under different weather to validate the conclusion of simulation.

  16. The analytical approach to optimization of active region structure of quantum dot laser

    International Nuclear Information System (INIS)

    Korenev, V V; Savelyev, A V; Zhukov, A E; Omelchenko, A V; Maximov, M V

    2014-01-01

    Using the analytical approach introduced in our previous papers we analyse the possibilities of optimization of size and structure of active region of semiconductor quantum dot lasers emitting via ground-state optical transitions. It is shown that there are optimal length' dispersion and number of QD layers in laser active region which allow one to obtain lasing spectrum of a given width at minimum injection current. Laser efficiency corresponding to the injection current optimized by the cavity length is practically equal to its maximum value

  17. The analytical approach to optimization of active region structure of quantum dot laser

    Science.gov (United States)

    Korenev, V. V.; Savelyev, A. V.; Zhukov, A. E.; Omelchenko, A. V.; Maximov, M. V.

    2014-10-01

    Using the analytical approach introduced in our previous papers we analyse the possibilities of optimization of size and structure of active region of semiconductor quantum dot lasers emitting via ground-state optical transitions. It is shown that there are optimal length' dispersion and number of QD layers in laser active region which allow one to obtain lasing spectrum of a given width at minimum injection current. Laser efficiency corresponding to the injection current optimized by the cavity length is practically equal to its maximum value.

  18. Promoting Active Learning in Calculus and General Physics through Interactive and Media-Enhanced Lectures

    Directory of Open Access Journals (Sweden)

    Guoqing Tang

    2004-02-01

    Full Text Available In this paper we present an approach of incorporating interactive and media-enhanced lectures to promote active learning in Calculus and General Physics courses. The pedagogical practice of using interactive techniques in lectures to require "heads-on" and "hands-on" learning, and involve students more as active participants than passive receivers is a part of academic curricular reform efforts undertaken currently by the mathematics, physics and chemistry departments at North Carolina A&T State University under the NSF funded project "Talent-21: Gateway for Advancing Science and Mathematics Talents."

  19. Are associations between electronic media use and BMI different across levels of physical activity?

    DEFF Research Database (Denmark)

    Melkevik, Ole; Haug, Ellen; Rasmussen, Mette

    2015-01-01

    and girls who did not comply with physical activity guidelines. Among physically active adolescents, EM was found to be significantly associated with BMI or odds for overweight among girls, but not among boys. CONCLUSION: While the usage of EM appear to be inconsequential for BMI and the risk of overweight...... among physically active boys, we find evidence indicating that EM use is associated with BMI and risk for overweight among girls, including those who report complying with MVPA guidelines.......BACKGROUND: The use of electronic media has been found to be a risk factor for higher BMI and for being overweight. Physical activity has been found to be associated with lower BMI and lower risk for being overweight. Little is known about whether the associations between physical activity...

  20. Interactions between 9,10-anthraquinone and aromatic amines in homogeneous and micellar media: A laser flash photolysis and magnetic field effect study

    International Nuclear Information System (INIS)

    Chowdhury, Adity; Basu, Samita

    2006-01-01

    The interactions between 9,10-anthraquinone (AQ) and different aromatic amines, N,N-dimethylaniline and 4,4'-bis (dimethylamino) diphenylmethane (DMDPM), have been studied using absorption, steady-state fluorescence, and laser flash photolysis techniques in organic homogeneous and heterogeneous micellar media. In polar organic homogeneous medium, electron transfer (ET) occurs from amines to excited AQ. In micellar medium, similar intermolecular ET is observed. However, in latter medium, ET predominates over hydrogen abstraction from micelles by excited AQ itself. The occurrence of ET has been further supported by the application of an external magnetic field during laser flash photolysis experiments, which modulates the yield of radical ion pairs formed through ET. Another novel feature, which has also been discussed here, is the abnormal behavior of DMDPM in micellar medium pertaining to energy transfer

  1. Media device ownership and media use: Associations with sedentary time, physical activity and fitness in English youth

    Directory of Open Access Journals (Sweden)

    Gavin R.H. Sandercock

    2016-12-01

    Higher weekend sedentary time was associated with low fitness in girls (p = 0.005 and boys (p 10 h or ~85% of each waking day sedentary. Use of social media was associated with higher sedentary time in both sexes and with low fitness in girls. Reducing social media use in youth offers one potential target for intervention. Behaviours associated with sedentary time differed from predictors of low fitness. The complex and often sex-specific interactions identified between sedentary time, PA and fitness suggest the need for carefully targeted interventions to reduce sedentary time and improve fitness in English youth.

  2. Laser cooling of solids

    CERN Document Server

    Petrushkin, S V

    2009-01-01

    Laser cooling is an important emerging technology in such areas as the cooling of semiconductors. The book examines and suggests solutions for a range of problems in the development of miniature solid-state laser refrigerators, self-cooling solid-state lasers and optical echo-processors. It begins by looking at the basic theory of laser cooling before considering such topics as self-cooling of active elements of solid-state lasers, laser cooling of solid-state information media of optical echo-processors, and problems of cooling solid-state quantum processors. Laser Cooling of Solids is an important contribution to the development of compact laser-powered cryogenic refrigerators, both for the academic community and those in the microelectronics and other industries. Provides a timely review of this promising field of research and discusses the fundamentals and theory of laser cooling Particular attention is given to the physics of cooling processes and the mathematical description of these processes Reviews p...

  3. Active mode-locking of mid-infrared quantum cascade lasers with short gain recovery time.

    Science.gov (United States)

    Wang, Yongrui; Belyanin, Alexey

    2015-02-23

    We investigate the dynamics of actively modulated mid-infrared quantum cascade lasers (QCLs) using space- and time-domain simulations of coupled density matrix and Maxwell equations with resonant tunneling current taken into account. We show that it is possible to achieve active mode locking and stable generation of picosecond pulses in high performance QCLs with a vertical laser transition and a short gain recovery time by bias modulation of a short section of a monolithic Fabry-Perot cavity. In fact, active mode locking in QCLs with a short gain recovery time turns out to be more robust to the variation of parameters as compared to previously studied lasers with a long gain recovery time. We investigate the effects of spatial hole burning and phase locking on the laser output.

  4. Effect of green laser light on diabetes mellitus changed ATPase activity in erythrocytes

    International Nuclear Information System (INIS)

    Kassak, P.; Sikurova, L.

    2006-01-01

    Changes in the membrane bound enzyme activity may report about changes of processes and properties related to the cytoplasmic membrane of cells. Activity of the Na + /K + -ATPase has become objective of our investigation as o tool to evaluate changes of diabetic membranes in comparison to normal membranes of human erythrocytes after laser irradiation with Nd:YAG laser (532 nm) in fluence range 9.5-63.3 J · cm -2 . Energies of irradiation 3-20 joules and output power of the laser 30 mW classify this experiment as low-level laser therapy. Bio-stimulation of the enzyme, its activity as well as type-2 diabetes caused disorganisation and alternation of biological membrane and enzyme properties are discussed. (Authors)

  5. Ultra-short laser interactions with nanoparticles in different media: from electromagnetic to thermal and electrostatic effects

    Science.gov (United States)

    Itina, Tatiana E.

    2017-02-01

    Key issues of the controlled synthesis of nanoparticles and nanostructures, as well as laser-particle interactions are considered in the context of the latest applications appearing in many fields such as photonics, medicine, 3D printing, etc. The results of a multi-physics numerical study of laser interaction with nanoparticles will be presented in the presence of several environments. In particular, attention will be paid to the numerical study of laser interactions with heterogeneous materials (eg. colloidal liquids and/or nanoparticles in a dielectric medium) and the aggregation/sintering/fragmentation processes induced by ultra-short laser pulses.

  6. Higher media multi-tasking activity is associated with smaller gray-matter density in the anterior cingulate cortex.

    Directory of Open Access Journals (Sweden)

    Kep Kee Loh

    Full Text Available Media multitasking, or the concurrent consumption of multiple media forms, is increasingly prevalent in today's society and has been associated with negative psychosocial and cognitive impacts. Individuals who engage in heavier media-multitasking are found to perform worse on cognitive control tasks and exhibit more socio-emotional difficulties. However, the neural processes associated with media multi-tasking remain unexplored. The present study investigated relationships between media multitasking activity and brain structure. Research has demonstrated that brain structure can be altered upon prolonged exposure to novel environments and experience. Thus, we expected differential engagements in media multitasking to correlate with brain structure variability. This was confirmed via Voxel-Based Morphometry (VBM analyses: Individuals with higher Media Multitasking Index (MMI scores had smaller gray matter density in the anterior cingulate cortex (ACC. Functional connectivity between this ACC region and the precuneus was negatively associated with MMI. Our findings suggest a possible structural correlate for the observed decreased cognitive control performance and socio-emotional regulation in heavy media-multitaskers. While the cross-sectional nature of our study does not allow us to specify the direction of causality, our results brought to light novel associations between individual media multitasking behaviors and ACC structure differences.

  7. Synchrotron radiation and free electron laser activities in Novosibirsk

    International Nuclear Information System (INIS)

    Korchuganov, V.N.; Kulipanov, G.N.; Mezentsev, N.A.; Oreshkov, A.D.; Panchenko, V.E.; Pindyurin, V.F.; Skrinskij, A.N.; Sheromov, M.A.; Vinokurov, N.A.; Zolotarev, K.V.

    1994-01-01

    The results of studies realized in the Siberian synchrotron radiation centre within the frameworks of wide program of synchrotron radiation and free electron laser research are summarized. The technical information on the VEPP-2M, VEPP-3 and VEPP-4M storage rings used as synchrotron radiation sources is given. 10 refs.; 8 figs.; 12 tabs

  8. Cost-effectiveness analysis of a statewide media campaign to promote adolescent physical activity.

    Science.gov (United States)

    Peterson, Michael; Chandlee, Margaret; Abraham, Avron

    2008-10-01

    A cost-effectiveness analysis of a statewide social marketing campaign was performed using a statewide surveillance survey distributed to 6th through 12th graders, media production and placement costs, and 2000 census data. Exposure to all three advertisements had the highest impact on both intent and behavior with 65.6% of the respondents considering becoming more active and 58.3% reporting becoming more active. Average cost of the entire campaign was $4.01 per person to see an ad, $7.35 per person to consider being more active, and $8.87 per person to actually become more active, with billboards yielding the most positive cost-effectiveness. Findings highlight market research as an essential part of social marketing campaigns and the importance of using multiple marketing modalities to enhance cost-effectiveness and impact.

  9. Enhancing learning with the social media: student teachers’ perceptions on Twitter in a debate activity

    Directory of Open Access Journals (Sweden)

    Gemma Tur

    2015-01-01

    Full Text Available This paper presents research focused on the educational experience of students using the microblogging platform Twitter for debate activities in three groups in different teacher education programmes at the University of the Balearic Islands, Spain. The implementation of this technology-based task in a face-to-face class was introduced as an innovative experience as a way of enhancing student learning and fostering participation in the context of formal learning. The educational objectives of these activities, besides working on the topics of the debate, were to empower student teachers’ Personal Learning Environments, engage student participation and enhance their use of social media and mobile devices for learning. Student perceptions were assessed by means of a questionnaire completed by them at the end of the courses. Tweets related to the debate were also collected in order to obtain some statistical data on student participation. Data collected allowed the researchers to observe student teacher engagement with the use of Twitter for the debate activity and its impact on their learning and understanding of the debate topic. Results also showed positive perceptions towards the use of social media in education and students’ willingness for future use, learning opportunities from Twitter and the use of mobile technology were also envisioned. Finally, conclusions argue the implications for practice of the current study and highlight some issues for further research, such as the exploration of new and innovative uses for teachers’ professional development and the empowerment of new activities and habits in learning on the move.

  10. Control of Natural Zeolite Properties by Mechanical Activation in Stirred Media Mill

    Directory of Open Access Journals (Sweden)

    Bohács K.

    2017-06-01

    Full Text Available Due to the special characteristics of zeolites, they can be applied in a very wide range of industries, i.e. agricultural, environmental or water treatment purposes. Generally, high added value zeolite products are manufactured by micro- or nanogrinding. However, these processes require high energy input and cause significant wearing of the mill parts. Therefore, the optimization of zeolite grinding, as well as the control of its properties are of a great importance. In the present paper a Hungarian natural zeolite was mechanically activated in stirred media mill for various residence times in distilled water, meanwhile the particle size distribution and the grinding energy were measured. Additionally, on-line tube rheometer was used to study the rheology of the suspension during the grinding process. The particle interaction and the suspension aggregation stability were detected by zeta-potential measurements. Structural changes due to the mechanical activation process were monitored by FTIR. It was found that the material structure of the zeolite, as well as the rheological behaviour of the zeolite suspension and its aggregation stability had been altered due to the mechanical activation in the stirred media mill. It can be concluded that the zeolite product properties can be modified by mechanical activation in order to produce a high added value tailored material.

  11. Does neighbourhood walkability moderate the effects of mass media communication strategies to promote regular physical activity?

    Science.gov (United States)

    Barnes, R; Giles-Corti, B; Bauman, A; Rosenberg, M; Bull, F C; Leavy, J E

    2013-02-01

    Mass media campaigns are widely used in Australia and elsewhere to promote physical activity among adults. Neighbourhood walkability is consistently shown to be associated with walking and total activity. Campaigns may have different effects on individuals living in high and low walkable neighbourhoods. The purpose of this study is to compare pre- and post-campaign cognitive and behavioural impacts of the Heart Foundation's Find Thirty every day® campaign, in respondents living in high and lower walkable neighbourhoods. Pre- and post-campaign cross-sectional survey data were linked with objectively measured neighbourhood walkability. Cognitive and behavioural impacts were assessed using logistic regression stratified by walkability. Cognitive impacts were significantly higher post-campaign and consistently higher in respondents in high compared with lower walkable neighbourhoods. Post campaign sufficient activity was significantly higher and transport walking significantly lower, but only in residents of lower walkable areas. Cognitive impacts of mass media physical activity campaigns may be enhanced by living in a more walkable neighbourhood.

  12. Pricing a Protest: Forecasting the Dynamics of Civil Unrest Activity in Social Media.

    Directory of Open Access Journals (Sweden)

    Brian J Goode

    Full Text Available Online social media activity can often be a precursor to disruptive events such as protests, strikes, and "occupy" movements. We have observed that such civil unrest can galvanize supporters through social networks and help recruit activists to their cause. Understanding the dynamics of social network cascades and extrapolating their future growth will enable an analyst to detect or forecast major societal events. Existing work has primarily used structural and temporal properties of cascades to predict their future behavior. But factors like societal pressure, alignment of individual interests with broader causes, and perception of expected benefits also affect protest participation in social media. Here we develop an analysis framework using a differential game theoretic approach to characterize the cost of participating in a cascade, and demonstrate how we can combine such cost features with classical properties to forecast the future behavior of cascades. Using data from Twitter, we illustrate the effectiveness of our models on the "Brazilian Spring" and Venezuelan protests that occurred in June 2013 and November 2013, respectively. We demonstrate how our framework captures both qualitative and quantitative aspects of how these uprisings manifest through the lens of tweet volume on Twitter social media.

  13. Pricing a Protest: Forecasting the Dynamics of Civil Unrest Activity in Social Media.

    Science.gov (United States)

    Goode, Brian J; Krishnan, Siddharth; Roan, Michael; Ramakrishnan, Naren

    2015-01-01

    Online social media activity can often be a precursor to disruptive events such as protests, strikes, and "occupy" movements. We have observed that such civil unrest can galvanize supporters through social networks and help recruit activists to their cause. Understanding the dynamics of social network cascades and extrapolating their future growth will enable an analyst to detect or forecast major societal events. Existing work has primarily used structural and temporal properties of cascades to predict their future behavior. But factors like societal pressure, alignment of individual interests with broader causes, and perception of expected benefits also affect protest participation in social media. Here we develop an analysis framework using a differential game theoretic approach to characterize the cost of participating in a cascade, and demonstrate how we can combine such cost features with classical properties to forecast the future behavior of cascades. Using data from Twitter, we illustrate the effectiveness of our models on the "Brazilian Spring" and Venezuelan protests that occurred in June 2013 and November 2013, respectively. We demonstrate how our framework captures both qualitative and quantitative aspects of how these uprisings manifest through the lens of tweet volume on Twitter social media.

  14. The activation of aluminium by mercury ions in non-aggressive media

    Energy Technology Data Exchange (ETDEWEB)

    Bessone, J.B. [INIEC-Dto de Ingenieria Quimica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)]. E-mail: jbessone@criba.edu.ar

    2006-12-15

    The presence of Hg at concentration less than 300 ppm in Al base alloys causes their passivation breakdown. On alloys used as sacrificial anodes, it causes a major lowering (>0.3 V) in their operational potential in chloride media. Mercury as trace constituent in the natural gas stream causes severe damage to cryogenic heat exchangers. The present paper presents evidences of the mechanism by which mercury produces its pronounced effect in aqueous non-aggressive media. The work was carried out using pure (99.99%) aluminium and mercury (II) acetate solutions of different concentrations and pH. Open circuit potential-time responses were obtained. The surface effects were followed by means of scanning microscopy and EDAX/X-Ray analysis. The results demonstrate that immediately after immersion, the initial air-formed oxide film underwent a dynamic crack-healing process at flaws in the film, possible associated to grain boundaries. The subsequent healing process, if any, depends on the media composition. Thus, in this special case, Hg{sup 2+} ions can be directly reduced on the bare aluminium, reaching a true metallic contact, and initiating surface diffusion. This enables the formation of an amalgam. Aluminium atoms diffuse through the liquid mercury and undergo oxidation at the amalgam/electrolyte interface. This process is responsible for the oxide detachment (by undermining) and the attack morphology (i.e., wide cavities). The presence of aggressive anions is not needed to initiate activation.

  15. Micro-poromechanics model of fluid-saturated chemically active fibrous media.

    Science.gov (United States)

    Misra, Anil; Parthasarathy, Ranganathan; Singh, Viraj; Spencer, Paulette

    2015-02-01

    We have developed a micromechanics based model for chemically active saturated fibrous media that incorporates fiber network microstructure, chemical potential driven fluid flow, and micro-poromechanics. The stress-strain relationship of the dry fibrous media is first obtained by considering the fiber behavior. The constitutive relationships applicable to saturated media are then derived in the poromechanics framework using Hill's volume averaging. The advantage of this approach is that the resultant continuum model accounts for the discrete nature of the individual fibers while retaining a form suitable for porous materials. As a result, the model is able to predict the influence of micro-scale phenomena, such as the fiber pre-strain caused by osmotic effects and evolution of fiber network structure with loading, on the overall behavior and in particular, on the poromechanics parameters. Additionally, the model can describe fluid-flow related rate-dependent behavior under confined and unconfined conditions and varying chemical environments. The significance of the approach is demonstrated by simulating unconfined drained monotonic uniaxial compression under different surrounding fluid bath molarity, and fluid-flow related creep and relaxation at different loading-levels and different surrounding fluid bath molarity. The model predictions conform to the experimental observations for saturated soft fibrous materials. The method can potentially be extended to other porous materials such as bone, clays, foams and concrete.

  16. Poromechanics Parameters of Fluid-Saturated Chemically Active Fibrous Media Derived from a Micromechanical Approach.

    Science.gov (United States)

    Misra, Anil; Parthasarathy, Ranganathan; Singh, Viraj; Spencer, Paulette

    2013-01-01

    The authors have derived macroscale poromechanics parameters for chemically active saturated fibrous media by combining microstructure-based homogenization with Hill's volume averaging. The stress-strain relationship of the dry fibrous media is first obtained by considering the fiber behavior. The constitutive relationships applicable to saturated media are then derived in the poromechanics framework using Hill's Lemmas. The advantage of this approach is that the resultant continuum model assumes a form suited to study porous materials, while retaining the effect of discrete fiber deformation. As a result, the model is able to predict the influence of microscale phenomena such as fiber buckling on the overall behavior, and in particular, on the poromechanics constants. The significance of the approach is demonstrated using the effect of drainage and fiber nonlinearity on monotonic compressive stress-strain behavior. The model predictions conform to the experimental observations for articular cartilage. The method can potentially be extended to other porous materials such as bone, clays, foams, and concrete.

  17. Extreme nonlinearities in InAs/InP nanowire gain media: the two-photon induced laser

    DEFF Research Database (Denmark)

    Capua, Amir; Kami, Ouri; Eisenstein, Gadi

    2012-01-01

    We demonstrate a novel laser oscillation scheme in an InAs / InP wire-like quantum dash gain medium. A short optical pulse excites carriers by two photon absorption which relax to the energy levels providing gain thereby enabling laser oscillations. The nonlinear dynamic interaction is analyzed a...

  18. Analysis of the Interaction of Pulsed Laser with Nanoporous Activated Carbon Cloth

    Institute of Scientific and Technical Information of China (English)

    B.V. Kalucljerovic; M.S. Trtica; B.B. Radak; J.M. Stasic; S.S. Krstic Musovic; V.M. Dodevski

    2011-01-01

    Interaction of pulsed transversely excited atmospheric (TEA) CO2-1aser radiation at 10.6 μm with nanoporous activated carbon cloth was investigated. Activated carbon cloth of different adsorption characteristics was used. Activated carbon cloth modifications were initiated by laser pulse intensities from 0.5 to 28 MW/cm^2, depending on the cloth adsorption characteristics. CO2 laser radiation was effectively absorbed by the used activated carbon cloth and largely converted into thermal energy. The type of modification depended on laser power density, number of pulses, but mostly on material characteristics such as specific surface area. The higher the surface area of activated carbon cloth, the higher the damage threshold.

  19. Simultaneous realization of a coherent perfect absorber and laser by zero-index media with both gain and loss

    KAUST Repository

    Bai, Ping

    2016-12-20

    We investigate a unique type of zero-index medium with both gain and loss (ZIMGL), whose effective permittivity and permeability are both purely imaginary but of opposite signs. We analytically show that, by using a slab of ZIMGL with equal magnitude of loss and gain, simulation realization of a coherent perfect absorber (CPA) and laser, i.e., the so-called CPA laser, can be achieved. Previously the CPA laser was proposed in parity-time (PT) symmetric systems. However, the ZIMGL does not possess the PT symmetry and thus the underlying physics is distinctly different. By designing a photonic crystal (PC) composed of core-shell rods, with loss and gain distributed in either the core or the shell, we have realized such a ZIMGL. The CPA-laser functionality of such a PC is also confirmed in our numerical simulations. Our work provides a different approach for simultaneous realization of CPA and laser besides PT-symmetric systems.

  20. XeCl Excimer Laser with Three- and Four-Component Mixture of Active Gases

    International Nuclear Information System (INIS)

    Iwanejko, L.; Pokora, L.

    1998-01-01

    Selected results of investigations of a XeCl excimer laser employing a new type (four-component)of mixture of gases, He-Kr:Xe-HCl, are presented. The mixture includes, instead of Xe, a mixture of not-separated Kr and Xe gases, much less expensive than pure xenon. A comparison of durations and energies of pulses generated in the XeCl excimer laser using three- or four-component gaseous active medium (He-Xe-HCl or He-Kr:Xe-HCl) is made. The investigations have been carried out with the use of a laser system with UV preionization and self sustained pumping discharge. (author)

  1. Laser-activated nano-biomaterials for tissue repair and controlled drug release

    International Nuclear Information System (INIS)

    Matteini, P; Ratto, F; Rossi, F; Pini, R

    2014-01-01

    We present recent achievements of minimally invasive welding of biological tissue and controlled drug release based on laser-activated nano-biomaterials. In particular, we consider new advancements in the biomedical application of near-IR absorbing gold nano-chromophores as an original solution for the photothermal repair of surgical incisions and as nanotriggers of controlled drug release from hybrid biopolymer scaffolds. (laser biophotonics)

  2. Brain activation upon ideal-body media exposure followed by peer feedback in late adolescents

    NARCIS (Netherlands)

    Veldhuis, J.; van der Meulen, Mara; Braams, Barbara; Peters, Sabine; Konijn, E.A.; Crone, Eveline A.

    2016-01-01

    Media content matters in social contexts, especially for adolescents who socialize largely with their peers in media(ted) environments. This is well-exemplified by body image development being influenced by media's thin body-ideal and peer influences. This study investigated peer feedback and media

  3. Clinical and Spectrophotometric Evaluation of LED and Laser Activated Teeth Bleaching.

    Science.gov (United States)

    Lo Giudice, R; Pantaleo, G; Lizio, A; Romeo, U; Castiello, G; Spagnuolo, G; Giudice, G Lo

    2016-01-01

    Auxiliary power sources (LED and laser) are used in in-office teeth bleaching techniques to accelerate the redox reaction of the whitening gel to increase ease of use, to improve comfort and safety, and to decrease the procedure time. The aim this study is to evaluate the efficiency of the teeth whitening procedures performed with hydrogen peroxide and carbamide peroxide, LED or Laser activated. 18 patients, affected by exogenous dyschromia, were treated with a bleaching agent composed by 35% hydrogen peroxide and 10% carbamide peroxide. They were divided into two groups: in the first group the bleaching agent was activated by a LED lamp; in the second group it was activated by a Laser diode lamp. Both groups were subjected to 3 bleaching cycle of 15' each. The chromatic evaluations were performed before and after one week from the treatment, using a chromatic scale and a spectrophotometer. The mean value of pre, post bleaching and follow-up were analyzed using a T-test, with results statistically significant for Pbleaching effectiveness. All patients treated with laser activation complained an increase in dental sensitivity. The use of laser-activating systems did not improve the efficacy of bleaching.

  4. Digital Media-based Health Intervention on the promotion of Women's physical activity: a quasi-experimental study.

    Science.gov (United States)

    Peyman, Nooshin; Rezai-Rad, Majid; Tehrani, Hadi; Gholian-Aval, Mahdi; Vahedian-Shahroodi, Mohammad; Heidarian Miri, Hamid

    2018-01-15

    Technological advances have caused poor mobility and lower physical activity among humankind. This study was conducted to assess the impact of a digital media-based (multi-media, internet, and mobile phone) health intervention on promotion of women's physical activity. In this quasi-experimental study, 360 women were divided into case and control groups. The digital media-based educational intervention was conducted in two months in the case group electronically, using mail and Internet and telephone platforms. Physical activity was measured using International Physical Activity Questionnaire (IPAQ) that estimated women's physical activity rate in the previous week. Data was analyzed using descriptive and analytical statistics (ANOVA, chi-square, paired and independent t-tests) using SPSS 20. The mean score of knowledge, attitude and level of physical activity in the control group were not significantly different before and after the intervention. While in the case group, this difference before and after the intervention was significant (p digital media-based health education can be effective in improving health-based behavior such as physical activity. Therefore, it seems necessary to develop user-based strategies and strengthen the behavioral change theories and hypotheses based on digital media for effective influence on behavior. Iranian Registry of Clinical Trials (IRCT), IRCT20160619028529N5 . Registered December 24, 2017 [retrospectively registered].

  5. The action of microsecond-pulsed plasma-activated media on the inactivation of human lung cancer cells

    International Nuclear Information System (INIS)

    Kumar, Naresh; Park, Ji Hoon; Jeon, Su Nam; Park, Bong Sang; Choi, Eun Ha; Attri, Pankaj

    2016-01-01

    In the present work, we have generated reactive species (RS) through microsecond-pulsed plasma (MPP) in the cell culture media using a Marx generator with point–point electrodes of approximately 0.06 J discharge energy/pulse. RS generated in culture media through MPP have a selective action between growth of the H460 lung cancer cells and L132 normal lung cells. We observed that MPP-activated media (MPP-AM) induced apoptosis on H460 lung cancer cells through an oxidative DNA damage cascade. Additionally, we studied the apoptosis-related mRNA expression, DNA oxidation and polymerase-1 (PARP-1) cleaved analysis from treated cancer cells. The result proves that radicals generated through MPP play a pivotal role in the activation of media that induces the selective killing effect. (paper)

  6. Colloidal-Quantum-Dot Ring Lasers with Active Color Control.

    Science.gov (United States)

    le Feber, Boris; Prins, Ferry; De Leo, Eva; Rabouw, Freddy T; Norris, David J

    2018-02-14

    To improve the photophysical performance of colloidal quantum dots for laser applications, sophisticated core/shell geometries have been developed. Typically, a wider bandgap semiconductor is added as a shell to enhance the gain from the quantum-dot core. This shell is designed to electronically isolate the core, funnel excitons to it, and reduce nonradiative Auger recombination. However, the shell could also potentially provide a secondary source of gain, leading to further versatility in these materials. Here we develop high-quality quantum-dot ring lasers that not only exhibit lasing from both the core and the shell but also the ability to switch between them. We fabricate ring resonators (with quality factors up to ∼2500) consisting only of CdSe/CdS/ZnS core/shell/shell quantum dots using a simple template-stripping process. We then examine lasing as a function of the optical excitation power and ring radius. In resonators with quality factors >1000, excitons in the CdSe cores lead to red lasing with thresholds at ∼25 μJ/cm 2 . With increasing power, green lasing from the CdS shell emerges (>100 μJ/cm 2 ) and then the red lasing begins to disappear (>250 μJ/cm 2 ). We present a rate-equation model that can explain this color switching as a competition between exciton localization into the core and stimulated emission from excitons in the shell. Moreover, by lowering the quality factor of the cavity we can engineer the device to exhibit only green lasing. The mechanism demonstrated here provides a potential route toward color-switchable quantum-dot lasers.

  7. Fabrication of SERS Active Surface on Polyimide Sample by Excimer Laser Irradiation

    Directory of Open Access Journals (Sweden)

    T. Csizmadia

    2014-01-01

    Full Text Available A possible application of excimer laser irradiation for the preparation of surface enhanced Raman spectroscopy (SERS substrate is demonstrated. A polyimide foil of 125 μm thickness was irradiated by 240 pulses of focused ArF excimer laser beam (λ = 193 nm, FWHM = 20 ns. The applied fluence was varied between 40 and 80 mJ/cm2. After laser processing, the sample was coated with 40 nm silver by PLD in order to create a conducting layer required for the SERS application. The SERS activity of the samples was tested by Raman microscopy. The Raman spectra of Rhodamine 6G aqueous solution (c=10−3 mol/dm3 were collected from the patterned and metalized areas. For areas prepared at 40–60 mJ/cm2 laser fluences, the measured Raman intensities have shown a linear dependence on the applied laser fluence, while above 60 mJ/cm2 saturation was observed. The morphology of the SERS active surface areas was investigated by scanning electron microscopy. Finite element modeling was performed in order to simulate the laser-absorption induced heating of the polyimide foil. The simulation resulted in the temporal and spatial distribution of the estimated temperature in the irradiated polyimide sample, which are important for understanding the structure formation process.

  8. Ablation, surface activation, and electroless metallization of insulating materials by pulsed excimer laser irradiation

    International Nuclear Information System (INIS)

    Lowndes, D.H.; Godbole, M.J.; Pedraza, A.J.

    1993-01-01

    Pulsed-laser irradiation of wide bandgap ceramic substrates, using photons with sub-bandgap energies, activates the ceramic surface for subsequent electroless copper deposition. The copper deposit is confined within the irradiated region when the substrate is subsequently immersed in an electroless copper bath. However, a high laser fluence (typically several j/cm 2 ) and repeated laser shots are needed to obtain uniform copper coverage by this direct-irradiation process. In contrast, by first applying an evaporated SiO x thin film (with x ∼1), laser ablation at quite low energy density (∼0.5 J/cm 2 ) results in re-deposition on the ceramic substrate of material that is catalytic for subsequent electroless copper deposition. Experiments indicate that the re-deposited material is on silicon, on which copper nucleates. Using an SiO x film on a laser-transparent substrate, quite fine (∼12 μm) copper lines can be formed at the boundary of the region that is laser-etched in SiO x . Using SiO x with an absorbing (polycrystalline) ceramic substrate, more-or-less uniform activation and subsequent copper deposition are obtained. In the later case, interactions with the ceramic substrate also may be important for uniform deposition

  9. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang; Hwang, Sooyeon; Wang, Maoyu; Feng, Zhenxing; Karakalos, Stavros; Luo, Langli; Qiao, Zhi; Xie, Xiaohong; Wang, Chongmin; Su, Dong; Shao, Yuyan; Wu, Gang (BNL); (Oregon State U.); (SC); (PNNL); (Buffalo)

    2017-09-26

    It remains a grand challenge to replace platinum group metal (PGM) catalysts with earth-abundant materials for the oxygen reduction reaction (ORR) in acidic media, which is crucial for large-scale deployment of proton exchange membrane fuel cells (PEMFCs). Here, we report a high-performance atomic Fe catalyst derived from chemically Fe-doped zeolitic imidazolate frameworks (ZIFs) by directly bonding Fe ions to imidazolate ligands within 3D frameworks. Although the ZIF was identified as a promising precursor, the new synthetic chemistry enables the creation of well-dispersed atomic Fe sites embedded into porous carbon without the formation of aggregates. The size of catalyst particles is tunable through synthesizing Fe-doped ZIF nanocrystal precursors in a wide range from 20 to 1000 nm followed by one-step thermal activation. Similar to Pt nanoparticles, the unique size control without altering chemical properties afforded by this approach is able to increase the number of PGM-free active sites. The best ORR activity is measured with the catalyst at a size of 50 nm. Further size reduction to 20 nm leads to significant particle agglomeration, thus decreasing the activity. Using the homogeneous atomic Fe model catalysts, we elucidated the active site formation process through correlating measured ORR activity with the change of chemical bonds in precursors during thermal activation up to 1100 °C. The critical temperature to form active sites is 800 °C, which is associated with a new Fe species with a reduced oxidation number (from Fe3+ to Fe2+) likely bonded with pyridinic N (FeN4) embedded into the carbon planes. Further increasing the temperature leads to continuously enhanced activity, linked to the rise of graphitic N and Fe–N species. The new atomic Fe catalyst has achieved respectable ORR activity in challenging acidic media (0.5 M H2SO4), showing a half-wave potential of 0.85 V vs RHE and leaving only a 30 mV gap with Pt/C (60 μgPt/cm2). Enhanced stability

  10. Towards passive and active laser stabilization using cavity-enhanced atomic interaction

    DEFF Research Database (Denmark)

    Schäffer, Stefan Alaric; Christensen, Bjarke Takashi Røjle; Rathmann, Stefan Mossor

    2017-01-01

    Ultra stable frequency references such as the ones used in optical atomic clocks and for quantum metrology may be obtained by stabilizing a laser to an optical cavity that is stable over time. State-of-the-art frequency references are constructed in this way, but their stabilities are currently...... experimental efforts derived from these proposals, to use cavity-enhanced interaction with atomic 88Sr samples as a frequency reference for laser stabilization. Such systems can be realized using both passive and active approaches where either the atomic phase response is used as an error signal, or the narrow...... atomic transition itself is used as a source for a spectrally pure laser. Both approaches shows the promise of being able to compete with the current state of the art in stable lasers and have similar limitations on their ultimately achievable linewidths [1, 2]....

  11. Active laser radar (lidar) for measurement of corresponding height and reflectance images

    Science.gov (United States)

    Froehlich, Christoph; Mettenleiter, M.; Haertl, F.

    1997-08-01

    For the survey and inspection of environmental objects, a non-tactile, robust and precise imaging of height and depth is the basis sensor technology. For visual inspection,surface classification, and documentation purposes, however, additional information concerning reflectance of measured objects is necessary. High-speed acquisition of both geometric and visual information is achieved by means of an active laser radar, supporting consistent 3D height and 2D reflectance images. The laser radar is an optical-wavelength system, and is comparable to devices built by ERIM, Odetics, and Perceptron, measuring the range between sensor and target surfaces as well as the reflectance of the target surface, which corresponds to the magnitude of the back scattered laser energy. In contrast to these range sensing devices, the laser radar under consideration is designed for high speed and precise operation in both indoor and outdoor environments, emitting a minimum of near-IR laser energy. It integrates a laser range measurement system and a mechanical deflection system for 3D environmental measurements. This paper reports on design details of the laser radar for surface inspection tasks. It outlines the performance requirements and introduces the measurement principle. The hardware design, including the main modules, such as the laser head, the high frequency unit, the laser beam deflection system, and the digital signal processing unit are discussed.the signal processing unit consists of dedicated signal processors for real-time sensor data preprocessing as well as a sensor computer for high-level image analysis and feature extraction. The paper focuses on performance data of the system, including noise, drift over time, precision, and accuracy with measurements. It discuses the influences of ambient light, surface material of the target, and ambient temperature for range accuracy and range precision. Furthermore, experimental results from inspection of buildings, monuments

  12. Thermal fluctuations in perpendicular recording media: New methodology for estimation of activation moment

    International Nuclear Information System (INIS)

    Mamiya, H; Oba, Y; Ohnuma, M; Hagiya, H; Oku, T; Suzuki, J; Yokoyama, M; Nishihara, Y; Katayama, T; Awano, H; Koda, T

    2011-01-01

    In nanoparticulate films with perpendicular magnetic anisotropy, a large demagnetizing field almost compensates for the experimentally designed change in the magnetic field applied parallel to the film normal. We propose a new method based on field-cycling to eliminate the uncertainty in the demagnetizing response from the analysis of the activation volume of the reversal or magnetic activation moment in such films. In this method, the applied field induced variation in the magnetic relaxation rate is measured before the effect of the demagnetizing field becomes dominant. We also discuss an analogical thermal-cycling method to clarify the temperature dependence of the barrier height for magnetization reversal in a magnetic field. We apply these methods to a Co 74 Pt 16 Cr 10 -SiO 2 nanoparticulate film as an example. The results demonstrate that these methods are useful for studying thermal fluctuations in perpendicular recording media.

  13. R and D on Radiation Hard Active Media Based on Quartz Plates

    CERN Document Server

    Onel, Yasar

    2014-01-01

    The need for radiation-hard active media in particle detectors is prominently dictated by the future colliders and the future operations of the Large Hadron Collider. The areas of implementation range from calorimetry to beamline instrumentation to specialized forward detectors e.g. luminosity monitors. In this context, we developed the idea of utilizing quartz plates with various surface coating properties as the active medium for such detectors. Plain quartz is a pure Cerenkov radiator which has quite limited photostatistics. In order to improve the efficiency of the photodetection, various methods were investigated including radiation hard wavelength shifters, p-terphenyl or 4pct gallium doped zinc oxide. The readout options include direct coupling of the photodetector to the quartz plate, or fibers. We have studied various geometries and readout options and constructed calorimeter prototypes. Here we report on the results of the previous tests, and the recent developments, which enable several factors of ...

  14. High-energy azimuthally polarized laser beam generation from an actively Q-switched Nd:YAG laser with c-cut YVO4 crystal

    Science.gov (United States)

    Guo, Jing; Zhang, Baofu; Jiao, Zhongxing; He, Guangyuan; Wang, Biao

    2018-05-01

    A high-energy, azimuthally polarized (AP) and actively Q-switched Nd:YAG laser is demonstrated. The thermal bipolar lensing effect in the Nd:YAG laser rod is used as a polarization discriminator, and a c-cut YVO4 crystal is inserted into the laser cavity to increase the mode-selecting ability of the cavity for AP mode. The laser generated AP pulses with maximum pulse energy as high as 4.2 mJ. To the best of our knowledge, this is the highest pulse energy obtained from an actively Q-switched AP laser. The pulse energy remained higher than 1 mJ over a wide range of repetition rates from 5 kHz to 25 kHz.

  15. Effect of maize seed laser irradiation on plant photosynthetic activity

    International Nuclear Information System (INIS)

    Antonov, M.; Stanev, V.; Velichkov, D.; Tsonev, Ts.

    1986-01-01

    Investigations were made with the two hybrids, H-708 and P x -20. The seeds were irradiated by a helium-neon quantum generator (L'vov-1 Electronica) with output power of 24 MW and 632.8 nm wave length. Once and twice irradiated seeds were sown on the 2nd, 5th and 10th day post irradiation. Changes in leaf area, chlorophyll content in the leaves, photosynthetic rate and its dependence on temperature and light, transpiration, stomatal resistance to CO 2 and total dry matter of the overground plant part were traced. Seed irradiation with laser rays did not affect the chlorophyll content of the leaves. The photosynthetic rate did not depend on the cultivar characteristics of the crop. Single and repeated irradiation of the hybrid H-708 in most case enhanced photosynthetic rate, but a similar effect was not observed in P x -20. Transpiration and CO 2 stomatal resistance were not equally affected by radiation. Laser rays enhanced the ability of the photosynthetic apparatus of the entire plants to use more efficiently high light intensities. The leaf area and the total plant dry matter increased in case of sowing on the 2nd and 5th day and a single irradiation and in case of sowing on the 5th and 10th day and twice repeated irradiations

  16. New Media and Peace Activism: the Case of “One Million Voices against FARC”

    Directory of Open Access Journals (Sweden)

    Valeria Rosato

    2014-01-01

    Full Text Available Recently, the spread of social media has undoubtedly contributed to further increasing the potential of civil society mobilizations. The ease of access to new communication technologies enhances the po- tential of civic movements, but it is still necessary to focus on the relationship between the creation and stability of digital ties and the sustainability of collective action. This article aims to examine the first and largest global civil mobilization promoted through a So- cial Network Site: the massive march on February 4th 2008 against the FARC, the Colombian guerrilla group. The objective is to analyze, several years after the fact, the characteristics and effects of this mo- bilization, which originated on the web to become a huge global march. Through the analysis of the literature it presents some reflections on the nature of these new forms of online activism, their potential and limits. Specifically, the case in question comprises a form of collective action that, while displaying impressive speed and the capacity to mobilize many people thanks to the new medium of communication, at the same time reveals its dependence on external actors with the ability to manipulate it for their own ends as well as its weakness in generating a thorough prospect for social change that can truly impact on Columbian society in the long run. In conclusion the present work shows that, in a complex environment characterized by high levels of conflict, the resources provided by ‘revolutionary’ new media are not sufficient to achieve concrete social change because the web, like a mirror, simply brings the same contradictions found in real space into a virtual space. Therefore, we suggest looking beyond the emotional impact produced by new media and more carefully analyzing the real dynamics of conflicts and the inevitable ‘imbrication’ of the digital and non-digital.

  17. Defect evolution and dopant activation in laser annealed Si and Ge

    DEFF Research Database (Denmark)

    Cristiano, F.; Shayesteh, M.; Duffy, R.

    2016-01-01

    Defect evolution and dopant activation are intimately related to the use of ion implantation and annealing, traditionally used to dope semiconductors during device fabrication. Ultra-fast laser thermal annealing (LTA) is one of the most promising solutions for the achievement of abrupt and highly...... doped junctions. In this paper, we report some recent investigations focused on this annealing method, with particular emphasis on the investigation of the formation and evolution of implant/anneal induced defects and their impact on dopant activation. In the case of laser annealed Silicon, we show...

  18. Media Outlet and Consumer Reactions to Promotional Activities of the Choose Health LA Restaurants Program in Los Angeles County.

    Science.gov (United States)

    Gase, Lauren N; Montes, Christine; Robles, Brenda; Tyree, Rachel; Kuo, Tony

    2016-01-01

    This study sought to assess promotional activities undertaken to raise public awareness of the Choose Health LA Restaurants program in Los Angeles County, an environmental change strategy that recognizes restaurants for offering reduced-size and healthier menu options. We used multiple methods to assess public awareness of and reactions to the promotional activities, including an assessment of the reach of core promotional activities, a content analysis of earned media, and an Internet panel survey. The study was conducted in Los Angeles County, home to more than 10 million residents. An online survey firm recruited participants for an Internet panel survey; to facilitate generalization of results to the county's population, statistical weights were applied to analyses of the survey data. Promotional activities to raise awareness of the program included community engagement, in-store promotion, and a media campaign. Outcomes included media impressions, the number of people who reported seeing the Choose Health LA Restaurants logo, and a description of the themes present in earned media. Collectively, paid media outlets reported 335 587 229 total impressions. The Internet panel survey showed that 12% of people reported seeing the program logo. Common themes in earned media included the Choose Health LA Restaurants program aims to provide restaurant patrons with more choices, represents a new opportunity for restaurants and public health to work together, will benefit participating restaurants, and will positively impact health. Promotional activities for the Choose Health LA Restaurants program achieved modest reach and positive reactions from media outlets and consumers. The program strategy and lessons learned can help inform present and future efforts to combine environmental and individually focused strategies that target key influences of consumer food selection.

  19. The mass media role in acceptance activities of Slovak Republic's Nuclear Regulatory Authority

    International Nuclear Information System (INIS)

    Seliga, Mojmir

    1998-01-01

    Communication is the vital link between Nuclear Regulatory Authority and the public. If people do not know and understand the facts on which optimal a safety energy choice decisions should be based they cannot make informed decisions on how their own objectives can be met. The following ten commandments of communications are pointed out: be yourself; be comfortable and confident; be honest; be brief; be human; be personal; be positive and consistent; be attentive; be energetic; be committed and sincere. The important aspect is to test whether the nuclear energy in the Slovak Republic is acceptable according to mandatory rules and if its operation is regulated by the state through the independent institution - the Nuclear Regulatory Authority of the Slovak Republic (UJD). The media in Slovakia has on important power. Many organizations are therefore apprehensive when dealing with the press, radio and television. Many people would simply prefer not to get panicked when the dreaded microphones and cameras do appear. UJD considers the whole area of public relations as an essential component of its activity. UJD intends to offer the public true, systematic, qualified, understandable and independent information, regarding the safety of nuclear power plants, as well as regarding the methods and results of UJD work. Generally, public information is considered a significant contribution to the creation of confidence into the regulatory work. The paper presents the UJD communication program and relations with media as well as the preparedness of public information in case of emergency

  20. Moderate plasma activated media suppresses proliferation and migration of MDCK epithelial cells

    International Nuclear Information System (INIS)

    Mohades, Soheila; Laroussi, Mounir; Maruthamuthu, Venkat

    2017-01-01

    Low-temperature plasma has been shown to have diverse biomedical uses, including its applications in cancer and wound healing. One recent approach in treating mammalian cells with plasma is through the use of plasma activated media (PAM), which is produced by exposing cell culture media to plasma. While the adverse effects of PAM treatment on cancerous epithelial cell lines have been recently studied, much less is known about the interaction of PAM with normal epithelial cells. In this paper, non-cancerous canine kidney MDCK (Madin-Darby Canine Kidney) epithelial cells were treated by PAM and time-lapse microscopy was used to directly monitor their proliferation and random migration upon treatment. While longer durations of PAM treatment led to cell death, we found that moderate levels of PAM treatment inhibited proliferation in these epithelial cells. We also found that PAM treatment reduced random cell migration within epithelial islands. Immunofluorescence staining showed that while there were no major changes in the actin/adhesion apparatus, there was a significant change in the nuclear localization of proliferation marker Ki-67, consistent with our time-lapse results. (paper)

  1. Frames and knowledge in mixed media: how activation changes information intake.

    Science.gov (United States)

    Veenstra, Aaron S; Sayre, Ben; Shah, Dhavan V; McLeod, Douglas M

    2008-08-01

    Many people consider strategic framing, the journalistic tendency to reduce politics to a game or competition focused on the tactical maneuvers of political actors, to be harmful to democracy because it erodes citizen interest in the democratic process. Our results demonstrate that this is not always the case. Testing the effects of textual strategic frames and video processing in a digital environment, we show that strategic frames may also provide a context that is more conducive to learning in mixed media news environments than that provided by value frames, those focused on the value conflict between principled policy opponents. Further analysis reveals that this effect is most clearly seen among people who read political blogs (i.e., those who are already active and interested in politics). Our data suggest that for individuals with cognitive networks built around ideological concerns, such as blog readers, value-framed messages provide cues to stop encoding new information, while strategically framed messages lead people to continue absorbing and learning in mixed media environments.

  2. How we used two social media tools to enhance aspects of active learning during lectures.

    Science.gov (United States)

    George, Daniel R; Dreibelbis, Tomi D; Aumiller, Betsy

    2013-12-01

    Medical education is evolving to include active learning approaches, yet some courses will remain lecture-based. Social media tools used by students may foster collaborative learning during lectures. We present preliminary results from a pilot study that integrated two 'social' technologies, Google Docs and SurveyMonkey, into 22 hour-long lectures for a course called "Social Influences on Health" attended by 154 students. At the conclusion of the semester, we reviewed student usage patterns with both technologies and collected data from students via course evaluations that included a standard Likert Scale. We used thematic analysis to identify emergent themes from evaluations. On average, students contributed 6 comments/questions to the Google Doc in each lecture, and 35 students participated in SurveyMonkey. Engagement with both technologies increased throughout the semester and no unprofessional incidents were observed. The mean student rating for integration of Google Docs and SurveyMonkey was 3.4 or "above average" (SD = 1.17). Thematic analysis identified perceived strengths of this approach as well as areas for improvement. Social media such as Google Docs and SurveyMonkey can facilitate interaction and provide students with control over content and flow of lecture-based courses, but educators must be mindful of practical and conceptual limitations.

  3. Turn-on delay of QD and QW laser diodes: What is the difference?

    International Nuclear Information System (INIS)

    Sokolovskii, G S; Dudelev, V V; Kolykhalova, E D; Deryagin, A G; Maximov, M V; Nadtochiy, A M; Kuchinskii, V I; Mikhrin, S S; Livshits, D A; Viktorov, E A; Erneux, T

    2013-01-01

    Turn-on delay of laser diodes with quantum-sized active media is investigated both theoretically and experimentally. In this research we show the striking difference in turn-on delay of quantum dot and quantum well laser diodes: With quantum-well lasers turn on delay tends to zero in the limit of high pumping, while with quantum dot lasers turn-on delay has the non-vanishing component which is independent of pumping

  4. Bubble-cell interactions with laser-activated polymeric microcapsules

    Science.gov (United States)

    Versluis, Michel; Lajoinie, Guillaume; van Rooij, Tom; Skachkov, Ilya; Kooiman, Klazina; de Jong, Nico; Physics of Fluids Group, University of Twente Team; Biomedical Engineering, Erasmus MC Team

    2015-11-01

    Polymeric microcapsules that are made light-absorbing by the addition of a dye in their shell can generate cavitation microbubbles with spatiotemporal control when irradiated by a pulsed laser. These particles less than 3 μm in size can circulate through the body, bind to tissues and are expected to be readily detected, even if a single cavitation bubble is produced. In this paper, we study the impact of such cavitation bubbles on a cell monolayer and quantify it in terms of cell poration and cell viability. Two capsules formulations were used; the first one encapsulates a low boiling point oil and induced less cell damage than the second that was loaded with a high boiling point oil. We also report the generation of stable bubbles by the first capsule formulation that completely absorb the cells in their close vicinity. Physics of Fluid group MIRA Institute for Biomedical Technology and Technical Medicine MESA+ Institute for Nanotechnology.

  5. Axicon-based annular laser trap for studies on sperm activity

    Science.gov (United States)

    Shao, Bing; Vinson, Jaclyn M.; Botvinick, Elliot L.; Esener, Sadik C.; Berns, Michael W.

    2005-08-01

    As a powerful and noninvasive tool, laser trapping has been widely applied for the confinement and physiological study of biological cells and organelles. Researchers have used the single spot laser trap to hold individual sperm and quantitatively evaluated the motile force generated by a sperm. Early studies revealed the relationship between sperm motility and swimming behavior and helped the investigations in medical aspects of sperm activity. As sperm chemotaxis draws more and more interest in fertilization research, the studies on sperm-egg communication may help to explain male or female infertility and provide exciting new approaches to contraception. However, single spot laser trapping can only be used to investigate an individual target, which has limits in efficiency and throughput. To study the chemotactic response of sperm to eggs and to characterize sperm motility, an annular laser trap with a diameter of several hundred microns is designed, simulated with ray tracing tool, and implemented. An axicon transforms the wavefront such that the laser beam is incident on the microscope objective from all directions while filling the back aperture completely for high efficiency trapping. A trapping experiment with microspheres is carried out to evaluate the system performance. The power requirement for annular sperm trapping is determined experimentally and compared with theoretical calculations. With a chemo-attractant located in the center and sperm approaching from all directions, the annular laser trapping could serve as a speed bump for sperm so that motility characterization and fertility sorting can be performed efficiently.

  6. [Development of an evidence-based media campaign to promote walking among physically inactive women and increased physical activity among adults].

    Science.gov (United States)

    Escalon, Hélène; Serry, Anne-Juliette; Nguyen-Thanh, Viêt; Vuillemin, Anne; Oppert, Jean-Michel; Sarrazin, Philippe; Verlhiac, Jean-Francois; Salanave, Benoît; Simon, Chantal; Tausan, Simona; Dailly, Olivier; Arwidson, Pierre

    2016-06-08

    This paper demonstrates the feasibility of developing a multimodal media campaign-based intervention to promote physical activity using theory, evidence and media campaign construction expertise. An evaluation of this media campaign and its various components is the next stage of this work..

  7. Laser Refractography

    CERN Document Server

    Rinkevichyus, B.S; Raskovskaya, I.L

    2010-01-01

    This book describes the basic principles of laser refractography, a flexible new diagnostic tool for measuring optically inhomogeneous media and flows. Laser refractography is based on digital imaging and computer processing of structured laser beam refraction (SLR) in inhomogeneous transparent media. Laser refractograms provide both qualitative and quantitative measurements and can be used for the study of fast and transient processes. In this book, the theoretical basis of refractography is explored in some detail, and experimental setups are described for measurement of transparent media using either 2D (passed radiation) or 3D (scattered radiation) refractograms. Specific examples and applications are discussed, including visualization of the boundary layer near a hot or cold metallic ball in water, and observation of edge effects and microlayers in liquids and gases. As the first book to describe this new and exciting technique, this monograph has broad cross-disciplinary appeal and will be of interest t...

  8. Quantification of the activity of biomolecules in microarrays obtained by direct laser transfer.

    Science.gov (United States)

    Dinca, V; Ranella, A; Farsari, M; Kafetzopoulos, D; Dinescu, M; Popescu, A; Fotakis, C

    2008-10-01

    The direct-writing technique laser-induced forward transfer has been employed for the micro-array printing of liquid solutions of the enzyme horseradish peroxidase and the protein Titin on nitrocellulose solid surfaces. The effect of two UV laser pulse lengths, femtosecond and nanosecond has been studied in relation with maintaining the activity of the transferred biomolecules. The quantification of the active biomolecules after transfer has been carried out using Bradford assay, quantitative colorimetric enzymatic assay and fluorescence techniques. Spectrophotometric measurements of the HRP and the Titin activity as well as chromatogenic and fluorescence assay studies have revealed a connection between the properties of the deposited, biologically active biomolecules, the experimental conditions and the target composition. The bioassays have shown that up to 78% of the biomolecules remained active after femtosecond laser transfer, while this value reduced to 54% after nanosecond laser transfer. The addition of glycerol in a percentage up to 70% in the solution to be transferred has contributed to the stabilization of the micro-array patterns and the increase of their resolution.

  9. Different Brain Network Activations Induced by Modulation and Nonmodulation Laser Acupuncture

    Directory of Open Access Journals (Sweden)

    Chang-Wei Hsieh

    2011-01-01

    Full Text Available The aim of this study is to compare the distinct cerebral activation with continued wave (CW and 10 Hz-modulated wave (MW stimulation during low-level laser acupuncture. Functional magnetic resonance imaging (fMRI studies were performed to investigate the possible mechanism during laser acupuncture stimulation at the left foot's yongquan (K1 acupoint. There are 12 healthy right-handed volunteers for each type of laser stimulation (10-Hz-Modulated wave: 8 males and 4 females; continued wave: 9 males and 3 females. The analysis of multisubjects in this experiment was applied by random-effect (RFX analysis. In CW groups, significant activations were found within the inferior parietal lobule, the primary somatosensory cortex, and the precuneus of left parietal lobe. Medial and superior frontal gyrus of left frontal lobe were also aroused. In MW groups, significant activations were found within the primary motor cortex and middle temporal gyrus of left hemisphere and bilateral cuneus. Placebo stimulation did not show any activation. Most activation areas were involved in the functions of memory, attention, and self-consciousness. The results showed the cerebral hemodynamic responses of two laser acupuncture stimulation modes and implied that its mechanism was not only based upon afferent sensory information processing, but that it also had the hemodynamic property altered during external stimulation.

  10. Chitosan-caffeic acid-genipin films presenting enhanced antioxidant activity and stability in acidic media.

    Science.gov (United States)

    Nunes, Cláudia; Maricato, Élia; Cunha, Ângela; Nunes, Alexandra; da Silva, José A Lopes; Coimbra, Manuel A

    2013-01-02

    The use of chitosan films has been limited due to their high degradability in aqueous acidic media. In order to produce chitosan films with high antioxidant activity and insoluble in acid solutions caffeic acid was grafted to chitosan by a radical mechanism using ammonium cerium (IV) nitrate (60 mM). Genipin was used as cross-linker. This methodology originated films with 80% higher antioxidant activity than the pristine film. Also, these films only lost 11% of their mass upon seven days immersion into an aqueous solution at pH 3.5 under stirring. The films surface wettability (contact angle 105°), mechanical properties (68 MPa of tensile strength and 4% of elongation at break), and thermal stability for temperatures lower than 300 °C were not significantly influenced by the covalent linkage of caffeic acid and genipin to chitosan. Due to their characteristics, mainly higher antioxidant activity and lower solubility, these are promising materials to be used as active films. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Comparative Study on Antistaphylococcal Activity of Lipopeptides in Various Culture Media

    Directory of Open Access Journals (Sweden)

    Maciej Jaśkiewicz

    2017-08-01

    Full Text Available Staphylococcus aureus bacteria are one of the leading microorganisms responsible for nosocomial infections as well as being the primary causative pathogen of skin and wound infections. Currently, the therapy of staphylococcal diseases faces many difficulties, due to a variety of mechanisms of resistance and virulence factors. Moreover, a number of infections caused by S. aureus are connected with biofilm formation that impairs effectiveness of the therapy. Short cationic lipopeptides that are designed on the basis of the structure of antimicrobial peptides are likely to provide a promising alternative to conventional antibiotics. Many research groups have proved a high antistaphylococcal potential of lipopeptides, however, the use of different protocols for determination of antimicrobial activity may be the reason for inconsistency of the results. The aim of this study was to learn how the use of various bacteriological media as well as solvents may affect activity of lipopeptides and their cyclic analogs. Obtained results showed a great impact of these variables. For example, cyclic analogs were more effective when dissolved in an aqueous solution of acetic acid and bovine serum albumin (BSA. The greater activity against planktonic cultures was found in brain-heart infusion broth (BHI and tryptic-soy broth (TSB, while the antibiofilm activity was higher in the Mueller-Hinton medium.

  12. LC HCAL Absorber And Active Media Comparisons Using a Particle-Flow Algorithm

    International Nuclear Information System (INIS)

    Magill, Steve; Kuhlmann, S.

    2006-01-01

    We compared Stainless Steel (SS) to Tungsten (W) as absorber for the HCAL in simulation using single particles (pions) and a Particle-Flow Algorithm applied to e + e - -> Z -> qqbar events. We then used the PFA to evaluate the performance characteristics of a LC HCAL using W absorber and comparing scintillator and RPC as active media. The W/Scintillator HCAL performs better than the SS/Scintillator version due to finer λ I sampling and narrower showers in the dense absorber. The W/Scintillator HCAL performs better than the W/RPC HCAL except in the number of unused hits in the PFA. Since this represents the confusion term in the PFA response, additional tuning and optimization of a W/RPC HCAL might significantly improve this HCAL configuration

  13. Connected Activism: Indigenous Uses of Social Media for Shaping Political Change

    Directory of Open Access Journals (Sweden)

    Marisa Elena Duarte

    2017-07-01

    Full Text Available Prior studies describe digital tactics as specific strategies actors apply within broader repertoires of contention, specifically in social and political contexts. A comparison of EZLN, Idle No More, and the ongoing Rio Yaqui water rights movement reveals the kinds of community knowledge work that has to happen prior to and around activating digital tactics in Indigenous rights movements, including choices in messaging and discourses of Indigeneity, targeting of movement opponents, and selection of digital tools and techniques. Activists harness these communicative affordances to practice a politics of visibility, cultivate solidarity, diffuse an Indigenous consciousness, enforce dominant governments’ trust and treaty responsibilities, and remind many of the irrevocable injustice of colonialism. Designing methodologies that account for specific Indigenous social and political contexts as well as the affordances of various digital environments is part of the future work of Indigenous media theorists.

  14. The Implementation Effort Islamic Law Norms in Activities for Overcoming Pornography and Pornoaction on Mass Media

    Directory of Open Access Journals (Sweden)

    Ramlani Lina Sinaulan

    2017-02-01

    Full Text Available This paper discusses the effort Islamic Law norms in activities for overcoming pornography and porno-action on mass media. By using normative legal research, the result found that the concept of Islamic law, behave based on sharia, shows the importance of shaping the personality traits of Islam (syakhsiyya Islāmiyya and based on the devotion and faith. Because of the relation to the formulation of the rule of law against pornography behavior, it can not be designed, prepared and formulated based on social values. Based on the facts of society, as a result of the moral decadence that led to a permissive attitude towards their cultural infiltration, the social values in assessing the behavior may become more permissive toward behavior. However, the use of religious norms which have universal properties will not change, and even capable of elastic with the times.

  15. DEVICE FOR MEASURING OF THERMAL LENS PARAMETERS IN LASER ACTIVE ELEMENTS WITH A PROBE BEAM METHOD

    Directory of Open Access Journals (Sweden)

    A. N. Zakharova

    2015-01-01

    Full Text Available We have developed a device for measuring of parameters of thermal lens (TL in laser active elements under longitudinal diode pumping. The measurements are based on the probe beam method. This device allows one to determine sign and optical power of the lens in the principal meridional planes, its sensitivity factor with respect to the absorbed pump power and astigmatism degree, fractional heat loading which make it possible to estimate integral impact of the photoelastic effect to the formation of TL in the laser element. The measurements are performed in a linearly polarized light at the wavelength of 532 nm. Pumping of the laser element is performed at 960 nm that makes it possible to study laser materials doped with Yb3+ and (Er3+, Yb3+ ions. The precision of measurements: for sensitivity factor of TL – 0,1 m-1/W, for astigmatism degree – 0,2 m-1/W, for fractional heat loading – 5 %, for the impact of the photoelastic effect – 0,5 × 10-6 K-1. This device is used for characterization of thermal lens in the laser active element from an yttrium vanadate crystal, Er3+,Yb3+:YVO .

  16. Effect of sample preparation on the discrimination of bacterial isolates cultured in liquid nutrient media using laser induced breakdown spectroscopy

    Science.gov (United States)

    Laser induced breakdown spectroscopy (LIBS) is used as the basis for discrimination between 2 genera of gram-negative bacteria and 2 genera of gram-positive bacteria representing pathogenic threats commonly found in poultry processing rinse waters. Because LIBS-based discrimination relies primarily ...

  17. Urban Adolescents’ Physical Activity Experience, Physical Activity Levels, and Use of Screen-Based Media during Leisure Time: A Structural Model

    Directory of Open Access Journals (Sweden)

    Hui Xie

    2018-01-01

    Full Text Available There is limited understanding of the relationship between physical activity and use of screen-based media, two important behaviors associated with adolescents’ health outcomes. To understand this relationship, researchers may need to consider not only physical activity level but also physical activity experience (i.e., affective experience obtained from doing physical activity. Using a sample predominantly consisting of African and Latino American urban adolescents, this study examined the interrelationships between physical activity experience, physical activity level, and use of screen-based media during leisure time. Data collected using self-report, paper and pencil surveys was analyzed using structural equation modeling. Results showed that physical activity experience was positively associated with physical activity level and had a direct negative relationship with use of non-active video games for males and a direct negative relationship with use of computer/Internet for both genders, after controlling for physical activity level. Physical activity level did not have a direct relationship with use of non-active video games or computer/Internet. However, physical activity level had a direct negative association with use of TV/movies. This study suggests that physical activity experience may play an important role in promoting physical activity and thwarting use of screen-based media among adolescents.

  18. Urban Adolescents’ Physical Activity Experience, Physical Activity Levels, and Use of Screen-Based Media during Leisure Time: A Structural Model

    Science.gov (United States)

    Xie, Hui; Scott, Jason L.; Caldwell, Linda L.

    2018-01-01

    There is limited understanding of the relationship between physical activity and use of screen-based media, two important behaviors associated with adolescents’ health outcomes. To understand this relationship, researchers may need to consider not only physical activity level but also physical activity experience (i.e., affective experience obtained from doing physical activity). Using a sample predominantly consisting of African and Latino American urban adolescents, this study examined the interrelationships between physical activity experience, physical activity level, and use of screen-based media during leisure time. Data collected using self-report, paper and pencil surveys was analyzed using structural equation modeling. Results showed that physical activity experience was positively associated with physical activity level and had a direct negative relationship with use of non-active video games for males and a direct negative relationship with use of computer/Internet for both genders, after controlling for physical activity level. Physical activity level did not have a direct relationship with use of non-active video games or computer/Internet. However, physical activity level had a direct negative association with use of TV/movies. This study suggests that physical activity experience may play an important role in promoting physical activity and thwarting use of screen-based media among adolescents. PMID:29410634

  19. The assessment of activities conducted by companies in social media in light of research concerning their users

    OpenAIRE

    Bogdan Gregor; Tomasz Kubiak

    2014-01-01

    Social media are not losing their popularity. Despite their long (sometimes a few years long) presence on the Internet, portals from this category are gradually strengthening their position with regard to the number of registered users. In July 2014 the biggest social media portal – Facebook – had 1,320,000,000 active accounts around the whole world. In Poland in July 2014 the number of active users of the portal reached 12,000,000. In the period from April 12 to May 25, 2014, the Department ...

  20. Time dependent growth of vertically aligned carbon nanotube forest using a laser activated catalytical CVD method

    NARCIS (Netherlands)

    Haluska, M.; Bellouard, Y.J.; Dietzel, A.H.

    2008-01-01

    We report the growth of vertically aligned single-wall and multi-wall carbon nanotube forest using a Laser Activated - Catalytic Chemical Vapor Deposition process. The experiments were performed in a cold-wall reactor filled with an ethylene-hydrogen-argon gas mixture in a 5:2:8 ratio at ambient

  1. InP based lasers and optical amplifiers with wire-/dot-like active regions

    DEFF Research Database (Denmark)

    Reithmaier, J. P.; Somers, A.; Deubert, S.

    2005-01-01

    Long wavelength lasers and semiconductor optical amplifiers based on InAs quantum wire/dot-like active regions were developed on InP substrates dedicated to cover the extended telecommunication wavelength range between 1.4 - 1.65 mm. In a brief overview different technological approaches will be ...

  2. Laser thermal annealing of Ge, optimized for highly activated dopants and diode ION/IOFF ratios

    DEFF Research Database (Denmark)

    Shayesteh, M.; O'Connell, D.; Gity, F.

    2014-01-01

    The authors compared the influence of laser thermal annealing (LTA) and rapid thermal annealing (RTA) on dopant activation and electrical performance of phosphorus and arsenic doped n+/p junction. High carrier concentration above 1020 cm-3 as well as an ION/IOFF ratio of approximately 105 and ide...

  3. Particle size distributions, size concentration relationships, and adherence to hands of selected geologic media derived from mining, smelting, and quarrying activities

    Energy Technology Data Exchange (ETDEWEB)

    Bergstrom, Carolyn; Shirai, Jeffry; Kissel, John, E-mail: jkissel@uw.edu

    2011-09-15

    Hand-to-mouth activity, especially in children, is a potentially significant pathway of exposure to soil contaminants. Hand-mouthing behavior is of particular concern in areas impacted by mining, smelting, and quarrying activities as these activities may lead to elevated levels of heavy metals in soil. In order to estimate potential exposures to contaminated geologic media attributable to hand-to-mouth contact, it is useful to characterize adherence of those media to skin, as contaminant concentrations in adhered media may differ greatly from unfractionated, whole media concentrations. Such an investigation has been undertaken to aid estimation of exposures to arsenic, cadmium, lead, and zinc in nine different geologic media collected in the Pacific Northwest region of the United States. After establishing the particle size distribution of each medium (fractions < 63 {mu}m, 63-150 {mu}m, 150-250 {mu}m, and 250 {mu}m-2 mm were determined) and target elemental concentrations within each particle size fraction, an active handling protocol involving six volunteers was conducted. Wet media always adhered to a greater extent than dry media and adhered media generally had higher elemental concentrations than bulk media. Regression analyses suggest smaller particle fractions may have higher elemental concentrations. Results of application of a maximum likelihood estimation technique generally indicate that handling of dry media leads to preferential adherence of smaller particle sizes, while handling of wet media does not. Because adhered material can differ greatly in particle size distribution from that found in bulk material, use of bulk concentrations in exposure calculations may lead to poor estimation of actual exposures. Since lead has historically been a metal of particular concern, EPA's Integrated Exposure Uptake Biokinetic (IEUBK) Model was used to examine the potential consequences of evaluating ingestion of the selected media assuming concentrations in

  4. Characterization of human erythroid burst-promoting activity derived from bone marrow conditioned media

    International Nuclear Information System (INIS)

    Porter, P.N.; Ogawa, M.

    1982-01-01

    Bone marrow conditioned media (BMCM) increases burst number and the incorporation of 59 Fe into heme by bursts when peripheral blood or bone marrow cells are cultured at limiting serum concentrations. Burst-promoting activity (BPA) has now been purified approximately 300-fold from this source by ion-exchange chromatography on DEAE-Sephadex and absorption chromatography on hydroxyapatite agarose gel. Marrow BPA increased burst number and hemoglobin (Hb) synthesis in a dose-dependent manner. A larger increase in Hb synthesis than in burst number was consistently observed, which was probably a consequence of the increase in the number of cells per burst that occurs in the presence of BPA. The role of BPA in culture could be distinguished from erythropoietin (Ep), since no bursts grew in the absence of Ep, whether or not BPA was present, and since it had no effect on the growth of erythroid colonies scored at day 5 of culture. Our purified fraction did not support the growth of CFU-C in culture. Activity was stable at temperatures of 70 degrees C or lower for 10 min; exposure to 80 degrees C resulted in approximately 50% loss of activity. BPA was completely inactivated by treatment at 100 degrees C for 10 min. Thus, human bone marrow cells produce a heat-sensitive factor that specifically promotes the growth of early erythroid progenitors in culture

  5. Some New Lidar Equations for Laser Pulses Scattered Back from Optically Thick Media Such as Clouds, Dense Aerosol Plumes, Sea Ice, Snow, and Turbid Coastal Waters

    Science.gov (United States)

    Davis, Anthony B.

    2013-01-01

    I survey the theoretical foundations of the slowly-but-surely emerging field of multiple scattering lidar, which has already found applications in atmospheric and cryospheric optics that I also discuss. In multiple scattering lidar, returned pulses are stretched far beyond recognition, and there is no longer a one-to-one connection between range and return-trip timing. Moreover, one can exploit the radial profile of the diffuse radiance field excited by the laser source that, by its very nature, is highly concentrated in space and collimated in direction. One needs, however, a new class of lidar equations to explore this new phenomenology. A very useful set is derived from radiative diffusion theory, which is found at the opposite asymptotic limit of radiative transfer theory than the conventional (single-scattering) limit used to derive the standard lidar equation. In particular, one can use it to show that, even if the simple time-of-flight-to-range connection is irretrievably lost, multiply-scattered lidar light can be used to restore a unique profiling capability with coarser resolution but much deeper penetration into a wide variety of optical thick media in nature. Several new applications are proposed, including a laser bathymetry technique that should work for highly turbid coastal waters.

  6. Pulsed laser triggered high speed microfluidic fluorescence activated cell sorter†‡

    Science.gov (United States)

    Wu, Ting-Hsiang; Chen, Yue; Park, Sung-Yong; Hong, Jason; Teslaa, Tara; Zhong, Jiang F.; Di Carlo, Dino; Teitell, Michael A.

    2014-01-01

    We report a high speed and high purity pulsed laser triggered fluorescence activated cell sorter (PLACS) with a sorting throughput up to 20 000 mammalian cells s−1 with 37% sorting purity, 90% cell viability in enrichment mode, and >90% purity in high purity mode at 1500 cells s−1 or 3000 beads s−1. Fast switching (30 μs) and a small perturbation volume (~90 pL) is achieved by a unique sorting mechanism in which explosive vapor bubbles are generated using focused laser pulses in a single layer microfluidic PDMS channel. PMID:22361780

  7. Excimer-laser-induced activation of Mg-doped GaN layers

    International Nuclear Information System (INIS)

    Lin, Y.-J.; Liu, W.-F.; Lee, C.-T.

    2004-01-01

    In this study, we investigated the 248 nm excimer-laser-induced activation of the Mg-doped GaN layers. According to the observed photoluminescence results and the x-ray photoelectron spectroscopy measurements, we found that the dissociation of the Mg-H complexes and the formation of hydrogenated Ga vacancies (i.e., V Ga H 2 ) and/or the Ga vacancies occupied by interstitial Mg during the laser irradiation process, led to an increase in the hole concentration

  8. Electron transport in solid targets and in the active mixture of a CO2 laser amplifier

    Science.gov (United States)

    Galkowski, A.

    The paper examines the use of the NIKE code for the Monte Carlo computation of the deposited energy profile and other characteristics of the absorption process of an electron beam in a solid target and the spatial distribution of primary ionization in the active mixture of a CO2 laser amplifier. The problem is considered in connection with the generation of intense electron beams and the acceleration of thin metal foils, as well as in connection with the electric discharge pumping of a CO2 laser amplifier.

  9. A history of semi-active laser dome and window materials

    Science.gov (United States)

    Sullivan, Roger M.

    2014-05-01

    Semi-Active Laser (SAL) guidance systems were developed starting in the mid-1960's and today form an important class of precision guided weapons. The laser wavelengths generally fall in the short wave infrared region of the spectrum. Relative to passive, image based, infrared seekers the optical demands placed on the domes or windows of SAL seekers is very modest, allowing the use of low cost, easily manufactured materials, such as polycarbonate. This paper will examine the transition of SAL window and dome science and technology from the laboratory to battlefield, with special emphasis on the story of polycarbonate domes.

  10. Improvement of the beam quality of a diode laser with two active broad-area segments

    DEFF Research Database (Denmark)

    Chi, Mingjun; Thestrup, B.; Mortensen, J.L.

    2003-01-01

    The beam quality of a diode laser with two active segments was improved using an external cavity with collimating optics, a grating, and an output coupler. The beam quality of the output beam, which is the first-order diffractive beam from the grating, was improved by a factor of 2, and at least...... half of the freely running power of the laser was coupled out from the external cavity. The output power can be enhanced further by the feedback from the zeroth-order beam. The possibility of improving the beam quality further is discussed and a new double-external-cavity configuration is suggested....

  11. Optimized Laser Thermal Annealing on Germanium for High Dopant Activation and Low Leakage Current

    DEFF Research Database (Denmark)

    Shayesteh, Maryam; O' Connell, Dan; Gity, Farzan

    2014-01-01

    In this paper, state-of-the-art laser thermal annealing is used to fabricate Ge diodes. We compared the effect of laser thermal annealing (LTA) and rapid thermal annealing (RTA) on dopant activation and electrical properties of phosphorus and Arsenic-doped n +/p junctions. Using LTA, high carrier...... implant conditions. On the other hand, RTA revealed very high I on/I off ratio ∼ 107 and n ∼ 1, at the cost of high dopant diffusion and lower carrier concentrations which would degrade scalability and access resistance....

  12. Broadband Optical Active Waveguides Written by Femtosecond Laser Pulses in Lithium Fluoride

    International Nuclear Information System (INIS)

    Chiamenti, Ismael; Costa, Larissa N. da; Kalinowski, Hypolito J.; Bonfigli, Francesca; Montereali, Rosa Maria; Gomes Anderson, S. L.

    2014-01-01

    Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 1550 nm. Visible photoluminescence spectra of the optically active F 2 and F 3 + color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10 −3 −10 −4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF

  13. Broadband Optical Active Waveguides Written by Femtosecond Laser Pulses in Lithium Fluoride

    Science.gov (United States)

    Ismael, Chiamenti; Francesca, Bonfigli; Anderson, S. L. Gomes; Rosa, Maria Montereali; Larissa, N. da Costa; Hypolito, J. Kalinowski

    2014-01-01

    Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 1550 nm. Visible photoluminescence spectra of the optically active F2 and F3+ color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10-3-10-4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF.

  14. Theoretical and experimental study of a laser-diode-pumped actively Q-switched Yb:NaY(WO4)2 laser with acoustic-optic modulator

    Science.gov (United States)

    Zhang, Haikun; Xia, Wei; Song, Peng; Wang, Jing; Li, Xin

    2018-03-01

    A laser-diode-pumped actively Q-switched Yb:NaY(WO4)2 laser operating at around 1040 nm is presented for the first time with acoustic-optic modulator. The dependence of pulse width on incident pump power for different pulse repetition rates is measured. By considering the Guassian spatial distribution of the intracavity photon density and the initial population-inversion density as well as the longitudinal distribution of the photon density along the cavity axis and the turn off time of the acoustic-optic Q-switch, the coupled equations of the actively Q-switched Yb:NaY(WO4)2 laser are given. The coupled rate equations are used to simulate the Q-switched process of laser, and the numerical solutions agree with the experimental results.

  15. Diode pumped actively Q-switched Nd:YVO4 self-Raman laser

    International Nuclear Information System (INIS)

    Su Fufang; Zhang Xingyu; Wang Qingpu; Ding Shuanghong; Jia Peng; Li Shutao; Fan Shuzhen; Zhang Chen; Liu Bo

    2006-01-01

    By using Nd:YVO 4 as the gain medium and the Raman medium simultaneously, the actively Q-switched operation of the self-Raman Nd:YVO 4 laser at 1176 nm was realized. The output characteristics including the average power, pulse energy and pulse width versus the incident pump power and pulse repetition rate were investigated. At a pulse repetition rate of 20 kHz an average power up to 0.57 W was obtained with the incident pump power of 10.2 W, corresponding to a conversion efficiency of 5.6% with respect to the diode laser input power. Meanwhile, an analysis of the self-Raman Nd:YVO 4 laser was carried out by using the rate equations. The obtained theoretical results were in agreement with the experimental results on the whole

  16. Impact of Social Media on Power Relations of Korean Health Activism

    OpenAIRE

    KyuJin Shim

    2014-01-01

    This case study explores how the Korea Leukemia Patient Group (KLPG) uses social media in its internal communication strategy and how that empowers its relationship with external counterparts. This study's findings indicate that the communication strategy of the local health Non-Governmental Organization (NGO) is changing in response to the increased effectiveness and impact of social media. Using social media (e.g., Twitter) the KLPG can quickly and effectively construct an issue-based advoc...

  17. Measurement of activity in social media – a challenge for contemporary marketing research

    Directory of Open Access Journals (Sweden)

    Joanna Płuciennik

    2013-06-01

    Full Text Available Popularity of social media among Internet users resulted in popularity of this medium among companies looking for contact with the participants of the community. Social media became as well a marketing research area of interest. Challenges social media researchers are facing, such as a combination of quantitative and qualitative aspects, and the problem of complexity and the selection of indicators, demonstrate the need to systematize the knowledge in this area.

  18. Rapid prototyping of reflectors for vehicle lighting using laser activated remote phosphor

    Science.gov (United States)

    Lachmayer, Roland; Kloppenburg, Gerolf; Wolf, Alexander

    2015-03-01

    Bright white light sources are of significant importance for automotive front lighting systems. Today's upper class vehicles mainly use HID or LED as light source. As a further step in this development laser diode based systems offer high luminance, efficiency and allow the realization of new styling concepts and new dynamic lighting functions. These white laser diode systems can either be realized by mixing different spectral sources or by combining diodes with specific phosphors. Based on the approach of generating light using a laser and remote phosphor, lighting modules are manufactured. Four blue laser diodes (450 nm) are used to activate a phosphor coating and thus to achieve white light. A segmented paraboloid reflector generates the desired light distribution for an additional car headlamp. We use high speed milling and selective laser melting to build the reflector system for this lighting module. We compare the spectral reflection grade of these materials. Furthermore the generated modules are analyzed regarding their efficiency and light distribution. The use of Rapid Prototyping technologies allows an early validation of the chosen concept and is supposed to reduce cost and time in the product development process significantly. Therefor we discuss costs and times of the applied manufacturing technologies.

  19. Corneal aldehyde dehydrogenase and glutathione S-transferase activity after excimer laser keratectomy in guinea pigs.

    Science.gov (United States)

    Bilgihan, K; Bilgihan, A; Hasanreisoğlu, B; Turkozkan, N

    1998-03-01

    The free radical balance of the eye may be changed by excimer laser keratectomy. Previous studies have demonstrated that excimer laser keratectomy increases the corneal temperature, decreases the superoxide dismutase activity of the aqueous, and induces lipid peroxidation in the superficial corneal stroma. Aldehyde dehydrogenase (ALDH) and glutathione S-transferase (GST) are known to play an important role in corneal metabolism, particularly in detoxification of aldehydes, which are generated from free radical reactions. In three groups of guinea pigs mechanical corneal de-epithelialisation was performed in group I, superficial corneal photoablation in group II, and deep corneal photoablation in group III, and the corneal ALDH and GST activities measured after 48 hours. The mean ALDH and GST activities of group I and II showed no differences compared with the controls (p > 0.05). The corneal ALDH activities were found to be significantly decreased (p < 0.05) and GST activities increased (p < 0.05) in group III. These results suggest that excimer laser treatment of high myopia may change the ALDH and GST activities, metabolism, and free radical balance of the cornea.

  20. Measurements of ultrasonic waves by means of laser Doppler velocimeter and an experimental study of elastic wave propagation in inhomogeneous media; Laser doppler sokudokei ni yoru choonpa keisoku to ganseki wo mochiita fukinshitsu baishitsu no hado denpa model jikken

    Energy Technology Data Exchange (ETDEWEB)

    Nishizawa, O; Sato, T [Geological Survey of Japan, Tsukuba (Japan); Lei, X [Dia Consultants Company, Tokyo (Japan)

    1996-05-01

    In the study of seismic wave propagation, a model experimenting technique has been developed using a laser Doppler velocimeter (LDV) as the sensor. This technique, not dependent on conventional piezoelectric devices, only irradiates the specimen with laser to measure the velocity amplitude on the target surface, eliminating the need for close contact between the specimen and sensor. In the experiment, elastic penetration waves with their noise levels approximately 0.05mm/s were observed upon application of vibration of 10{sup 6}-10{sup 5}Hz. The specimen was stainless steel or rock, and waveforms caught by the LDV and piezoelectric device were compared. As the result, it was found that the LDV is a powerful tool for effectively explaining elastic wave propagation in inhomogeneous media. The piezoelectric device fails to reproduce accurately the waves to follow the initial one while the LDV detect the velocity amplitude on the specimen surface in a wide frequency range encouraging the discussion over the quantification of observed waveforms. 10 refs., 7 figs.

  1. Role of endolymphatic anion transport in forskolin-induced Cl- activity increase of scala media.

    Science.gov (United States)

    Kitano, I; Mori, N; Matsunaga, T

    1995-03-01

    To determine the role of anion transport in the forskolin-induced Cl- increase of scala media (SM), effects of forskolin on the EP (endocochlear potential) and Cl- activity (ACl) in SM were examined with double-barrelled Cl(-)-selective microelectrodes. The experiments were carried out on guinea pig cochleae, using a few anion transport inhibitors: IAA-94 for a Cl- channel blocker, bumetanide (BU) for an Na+/K+/2Cl- cotransport blocker, and SITS and DIDS for Cl-/HCO3- exchange blockers. The application of forskolin (200 microM) into scala vestibuli (SV) caused a 20 mEq increase of endolymphatic ACl and a 15 mV elevation of EP, and IAA-94 with forskolin completely abolished these responses. Although each application of BU, SITS or DIDS did not completely suppress EP elevation, the concurrent application of these inhibitors completely suppressed EP with endolymphatic ACl increase. The results indicate the involvement of Cl- channels, Na+/K+/2Cl- cotransport and Cl-/HCO3- exchange in forskolin-induced increase of ACl and EP. The role of adenylate cyclase activation and Cl- transport in endolymph homeostasis was discussed.

  2. Adopt a Bacterium - an active and collaborative learning experience in microbiology based on social media.

    Science.gov (United States)

    Piantola, Marco Aurélio Floriano; Moreno, Ana Carolina Ramos; Matielo, Heloísa Alonso; Taschner, Natalia Pasternak; Cavalcante, Rafael Ciro Marques; Khan, Samia; Ferreira, Rita de Cássia Café

    2018-04-24

    The "Adopt a Bacterium" project is based on the use of social network as a tool in Microbiology undergraduate education, improving student learning and encouraging students to participate in collaborative learning. The approach involves active participation of both students and teachers, emphasizing knowledge exchange, based on widely used social media. Students were organized in groups and asked to adopt a specific bacterial genus and, subsequently, submit posts about "adopted genus". The formative assessment is based on posting information on Facebook®, and the summative assessment involves presentation of seminars about the adopted theme. To evaluate the project, students filled out three anonymous and voluntary surveys. Most of the students enjoyed the activities and positively evaluated the experience. A large amount of students declared a change in their attitude towards the way they processed information, especially regarding the use of scientific sources. Finally, we evaluated knowledge retention six months after the end of the course and students were able to recall relevant Microbiology concepts. Our results suggest that the "Adopt a Bacterium" project represents a useful strategy in Microbiology learning and may be applied to other academic fields. Copyright © 2018 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  3. 76 FR 6839 - ActiveCore Technologies, Inc., Battery Technologies, Inc., China Media1 Corp., Dura Products...

    Science.gov (United States)

    2011-02-08

    ... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] ActiveCore Technologies, Inc., Battery Technologies, Inc., China Media1 Corp., Dura Products International, Inc. (n/k/a Dexx Corp.), Global Mainframe Corp., GrandeTel Technologies, Inc., Magna Entertainment Corp. (n/k/a Reorganized Magna Entertainment...

  4. The assessment of activities conducted by companies in social media in light of research concerning their users

    Directory of Open Access Journals (Sweden)

    Bogdan Gregor

    2014-12-01

    Full Text Available Social media are not losing their popularity. Despite their long (sometimes a few years long presence on the Internet, portals from this category are gradually strengthening their position with regard to the number of registered users. In July 2014 the biggest social media portal – Facebook – had 1,320,000,000 active accounts around the whole world. In Poland in July 2014 the number of active users of the portal reached 12,000,000. In the period from April 12 to May 25, 2014, the Department of Marketing of the Faculty of Management of University of Lodz conducted a research aimed at the assessment of activities conducted by companies in social media. The goal of the research was to reach people using social media and investigate how particular measures taken by companies in social media are assessed by them, as well as to identify which of these actions boost engagement and influence making a purchasing decision. In course of the research the method of Internet questionnaire was applied. 302 respondents took part in the survey and almost 90% of them declared that they use social media portals. The most popular social network among the respondents is Facebook. YouTube also plays a major role. This may be seen as evidence that the marketing potential of video contents published on the Internet is huge. The conducted research shows that among the biggest benefits associated with having an account on a social media portal is the possibility of fast communication, chance to find and follow friends, as well as accumulation of the most important information in one place. Over 70% of the surveyed follows well-known companies and brands in social media. Fashion brands and brands associated with the food and electronics branches are followed most often. What the respondents most often named as one of the advantages of following brands in social media is the possibility of continuously following novelties, opportunity to receive discount coupons, as

  5. Blue-green ZnSe lasers with a new type of active region

    International Nuclear Information System (INIS)

    Ivanov, S.V.; Toropov, A.A.; Sorokin, S.V.; Shubina, T.V.; Sedova, I.V.; Kop'ev, P.S.; Alferov, Zh.I.; Waag, A.; Lugauer, H.J.; Reuscher, G.; Keim, M.; Fischer, F.F.; Landwehr, G.

    1999-01-01

    We report the results of an experimental study of molecular-beam epitaxy of ZnSe-based laser heterostructures with a new structure of the active region, which contains a fractional-monolayer CdSe recombination region in an expanded ZnSe quantum well and a waveguide based on a variably-strained, short-period superlattice are reported. Growth of a fractional-monolayer CdSe region with a nominal thickness of 2-3 ML, i.e., less than the critical thickness, on a ZnSe surface (Δa/a∼7%) leads to the formation of self-organized, pseudomorphic, CdSe-enriched islands with lateral dimensions ∼10-30 nm and density ∼2x10 10 cm -2 , which serve as efficient centers of carrier localization, giving rise to effective spatial separation of defective regions and regions of radiative recombination and, as a result, a higher quantum efficiency. Laser structures for optical pumping in the (Zn, Mg) (S, Se) system with a record-low threshold power density (less than 4 kW/cm 2 at 300 K) and continuous-wave laser diodes in the system (Be, Mg, Zn) Se with a 2.5 to 2.8-ML-thick, fractional-monolayer CdSe active region have been obtained. The laser structures and diodes have an improved degradation resistance

  6. SERS activity of silver and gold nanostructured thin films deposited by pulsed laser ablation

    Science.gov (United States)

    Agarwal, N. R.; Tommasini, M.; Fazio, E.; Neri, F.; Ponterio, R. C.; Trusso, S.; Ossi, P. M.

    2014-10-01

    Nanostructured Au and Ag thin films were obtained by nanosecond pulsed laser ablation in presence of a controlled Ar atmosphere. Keeping constant other deposition parameters such as target-to-substrate distance, incidence angle, laser wavelength and laser fluence, the film morphology, revealed by SEM, ranges from isolated NPs to island structures and sensibly depends on gas pressure (10-100 Pa) and on the laser pulse number (500-3 × 10). The control of these two parameters allows tailoring the morphology and correspondingly the optical properties of the films. The position and width of the surface plasmon resonance peak, in fact, can be varied with continuity. The films showed remarkable surface-enhanced Raman activity (SERS) that depends on the adopted deposition conditions. Raman maps were acquired on micrometer-sized areas of both silver and gold substrates selected among those with the strongest SERS activity. Organic dyes of interest in cultural heritage studies (alizarin, purpurin) have been also considered for bench marking the substrates produced in this work. Also the ability to detect the presence of biomolecules was tested using lysozyme in a label free configuration.

  7. Online Activities, Digital Media Literacy, and Networked Individualism of Korean Youth

    Science.gov (United States)

    Park, Sora; Kim, Eun-mee; Na, Eun-Yeong

    2015-01-01

    Networked individualism enables Internet users to connect and socialize via their loose and transient multiple networks, whereas digital media literacy is a precondition of effective Internet use. In this study, an attempt has been made to find the link between networked individualism, digital media literacy, and young people's perception of their…

  8. Decreasing Excessive Media Usage while Increasing Physical Activity: A Single-Subject Research Study

    Science.gov (United States)

    Larwin, Karen H.; Larwin, David A.

    2008-01-01

    The Kaiser Family Foundation released a report entitled "Kids and Media Use" in the United States that concluded that children's use of media--including television, computers, Internet, video games, and phones--may be one of the primary contributor's to the poor fitness and obesity of many of today's adolescents. The present study examines the…

  9. On the analysis of the activation mechanisms of sub-melt laser anneals

    International Nuclear Information System (INIS)

    Clarysse, T.; Bogdanowicz, J.; Goossens, J.; Moussa, A.; Rosseel, E.; Vandervorst, W.; Petersen, D.H.; Lin, R.; Nielsen, P.F.; Hansen, Ole; Merklin, G.; Bennett, N.S.; Cowern, N.E.B.

    2008-01-01

    In order to fabricate carrier profiles with a junction depth (∼15 nm) and sheet resistance value suited for sub-32 nm Si-CMOS technology, the usage of sub-melt laser anneal is a promising route to explore. As laser annealed junctions seem to outperform standard anneal approaches, a detailed assessment of the basics of laser induced activation seem appropriate. In this work the electrical activation is studied from a comparison between the dopant profiles as measured by Secondary Ion Mass Spectrometry, and the electrically active fraction as extracted from sheet resistance and mobility measurements. The latter is based on a large variety of techniques. For the sheet resistance we use conventional Four-Point Probe (FPP), Variable Probe Spacing (VPS), contactless junction photo voltage (JPV), Micro Four-Point Probe (M4PP) and an optical technique, namely Model Based Infra-red spectroscopic Reflectrometry (MBIR). For the sheet carrier density and sheet mobility extraction we use conventional Hall (without cloverleaf van der Pauw patterning, to reflect the need for fast turn-round sheet measurements), MBIR, and a recently developed new Hall-like capability using M4PP. By recognizing the interaction between the various parameters as they are not completely independent, it is possible to test the consistency of the various methods and to identify potential short comings. This concept is applied to the activation behavior of low and high implanted Boron doses and indicates that the obtained electrically active concentration level as well as the concurrent mobility is dependent on the dopant concentration level. This implies that the activation of B through the laser anneal process in the explored temperature-time space is governed by kinetic processes (i.e. the dissolution of B-I pairs) and not by the (temperature related) solid solubility

  10. Management of Formalised Marketing and Media Activities in Outsourcing Companies in the Age of Competitiveness, with Particular Emphasis on Contemporary Marketing Approach

    Directory of Open Access Journals (Sweden)

    Kozakowski Łukasz

    2015-10-01

    Full Text Available The article outlines the issues related to the topic of management of formalised marketing and media activities in outsourcing companies in the age of competitiveness, with particular emphasis on contemporary marketing approach. General management of the organisation and management of marketing and media activities, particularly in their formalised form, both have a significant effect on improving company competitiveness in the market. Outsourcing companies constitute a specific sector of services which without a very well-functioning marketing and media activities would not be able to operate and develop in the market. The article presents selected aspects connected with the management of marketing and media activities, with particular emphasis on formalisation of marketing activities in outsourcing companies. The analysis presented below focuses on the efficiency of the implemented formalisation of marketing and media activities in outsourcing companies in relation to their competitiveness, with special recognition of contemporary marketing approach.

  11. Impact of Social Media on Power Relations of Korean Health Activism

    Directory of Open Access Journals (Sweden)

    KyuJin Shim

    2014-07-01

    Full Text Available This case study explores how the Korea Leukemia Patient Group (KLPG uses social media in its internal communication strategy and how that empowers its relationship with external counterparts. This study’s findings indicate that the communication strategy of the local health Non-Governmental Organization (NGO is changing in response to the increased effectiveness and impact of social media. Using social media (e.g., Twitter the KLPG can quickly and effectively construct an issue-based advocacy group. Consequently, more legitimacy and representativeness through collected support from the general public have further empowered the KLPG. Yet, the sustainability component in the relationships built through social media use was not evidenced in the current findings. The effects of social media use were analyzed based on data from interviews with top-level KLPG executive members and general members, and from documentation and archival materials. Limitations and suggestions for future research are included.

  12. Quality assessment and anti-obesity activity of Stellaria media (Linn. Vill

    Directory of Open Access Journals (Sweden)

    Rani Neerja

    2012-09-01

    Full Text Available Abstract Background Obesity is recognized as a social problem, associated with serious health risks and increased mortality. Numerous trials have been conducted to find and develop new anti-obesity drugs through herbal sources to minimize side effects associated with the present anti-obesity drugs. The present study was designed to evaluate the quality control parameters, quantitative phytochemical analysis (total phenolic, total flavonoids and total saponin content, and the anti-obesity effect of lyophilized juice (LJ of Stellaria media (Linn. Vill. by employing in vitro and in vivo models. Methods In vitro studies were performed to evaluate the inhibitory activity of LJ on pancreatic amylase and lipase. The in vivo pancreatic lipase activity was evaluated by measurement of plasma triacylglycerol levels after oral administration of lipid emulsion to swiss albino mice. Furthermore, the anti-obesity effect of LJ was assessed at two doses, 400 mg/kg and 900 mg/kg body weight in mice fed a high-fat-diet with or without LJ for 6 weeks. Results The LJ inhibited pancreatic amylase and lipase activity in vitro and elevated plasma triacylglycerol level in mice. LJ suppressed the increase in body weight, retroperitoneal adipose tissue, liver weights and serum parameters viz., total cholesterol, total triglyceride, LDL-cholesterol level at the dose of 900 mg/kg body weight of the mice fed with high fat diet. The total phenolic, flavonoid and saponin contents were found to be 0.26 mg/g, 1.4 mg/g and 1.19 μg/g respectively of LJ. Conclusion The anti-obesity effects of LJ in high-fat-diet fed mice may be partly mediated through delaying the intestinal absorption of dietary fat and carbohydrate by inhibiting digestive enzymes.

  13. Induction of different activated phenotypes of mouse peritoneal macrophages grown in different tissue culture media.

    Science.gov (United States)

    Kawakami, Tomoya; Koike, Atsushi; Amano, Fumio

    2017-08-01

    The role of activated macrophages in the host defense against pathogens or tumor cells has been investigated extensively. Many researchers have been using various culture media in in vitro experiments using macrophages. We previously reported that J774.1/JA-4 macrophage-like cells showed great differences in their activated macrophage phenotypes, such as production of reactive oxygen, nitric oxide (NO) or cytokines depending on the culture medium used, either F-12 (Ham's F-12 nutrient mixture) or Dulbecco modified Eagle's medium (DMEM). To examine whether a difference in the culture medium would influence the functions of primary macrophages, we used BALB/c mouse peritoneal macrophages in this study. Among the activated macrophage phenotypes, the expression of inducible NO synthase in LPS- and/or IFN-γ-treated peritoneal macrophages showed the most remarkable differences between F-12 and DMEM; i.e., NO production by LPS- and/or IFN-γ-treated cells was far lower in DMEM than in F-12. Similar results were obtained with C57BL mouse peritoneal macrophages. Besides, dilution of F-12 medium with saline resulted in a slight decrease in NO production, whereas that of DMEM with saline resulted in a significant increase, suggesting the possibility that DMEM contained some inhibitory factor(s) for NO production. However, such a difference in NO production was not observed when macrophage-like cell lines were examined. These results suggest that phenotypes of primary macrophages could be changed significantly with respect to host inflammatory responses by the surrounding environment including nutritional factors and that these altered macrophage phenotypes might influence the biological host defense.

  14. Selective metallization of polymers using laser induced surface activation (LISA)—characterization and optimization of porous surface topography

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; De Grave, Arnaud

    2011-01-01

    Laser induced selective activation (LISA) is a molded interconnected devices technique for selective metallization of polymers. On the working piece, only the laser-machined area can be metalized in the subsequent plating. The principle of the technology is introduced. Surface analysis was perfor...

  15. Efficacy and causal mechanism of an online social media intervention to increase physical activity: Results of a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Jingwen Zhang

    2015-01-01

    Full Text Available Objective: To identify what features of social media – promotional messaging or peer networks – can increase physical activity. Method: A 13-week social media-based exercise program was conducted at a large Northeastern university in Philadelphia, PA. In a randomized controlled trial, 217 graduate students from the University were randomized to three conditions: a control condition with a basic online program for enrolling in weekly exercise classes led by instructors of the University for 13 weeks, a media condition that supplemented the basic program with weekly online promotional media messages that encourage physical activity, and a social condition that replaced the media content with an online network of four to six anonymous peers composed of other participants of the program, in which each participant was able to see their peers' progress in enrolling in classes. The primary outcome was the number of enrollments in exercise classes, and the secondary outcomes were self-reported physical activities. Data were collected in 2014. Results: Participants enrolled in 5.5 classes on average. Compared with enrollment in the control condition (mean = 4.5, promotional messages moderately increased enrollment (mean = 5.7, p = 0.08, while anonymous social networks significantly increased enrollment (mean = 6.3, p = 0.02. By the end of the program, participants in the social condition reported exercising moderately for an additional 1.6 days each week compared with the baseline, which was significantly more than an additional 0.8 days in the control condition. Conclusion: Social influence from anonymous online peers was more successful than promotional messages for improving physical activity. Clinical Trial Registration: ClinicalTrials.gov: NCT02267369.

  16. Efficacy and causal mechanism of an online social media intervention to increase physical activity: Results of a randomized controlled trial.

    Science.gov (United States)

    Zhang, Jingwen; Brackbill, Devon; Yang, Sijia; Centola, Damon

    2015-01-01

    To identify what features of social media - promotional messaging or peer networks - can increase physical activity. A 13-week social media-based exercise program was conducted at a large Northeastern university in Philadelphia, PA. In a randomized controlled trial, 217 graduate students from the University were randomized to three conditions: a control condition with a basic online program for enrolling in weekly exercise classes led by instructors of the University for 13 weeks, a media condition that supplemented the basic program with weekly online promotional media messages that encourage physical activity, and a social condition that replaced the media content with an online network of four to six anonymous peers composed of other participants of the program, in which each participant was able to see their peers' progress in enrolling in classes. The primary outcome was the number of enrollments in exercise classes, and the secondary outcomes were self-reported physical activities. Data were collected in 2014. Participants enrolled in 5.5 classes on average. Compared with enrollment in the control condition (mean = 4.5), promotional messages moderately increased enrollment (mean = 5.7, p = 0.08), while anonymous social networks significantly increased enrollment (mean = 6.3, p = 0.02). By the end of the program, participants in the social condition reported exercising moderately for an additional 1.6 days each week compared with the baseline, which was significantly more than an additional 0.8 days in the control condition. Social influence from anonymous online peers was more successful than promotional messages for improving physical activity. ClinicalTrials.gov: NCT02267369.

  17. Behaviour based Mobile Robot Navigation Technique using AI System: Experimental Investigation on Active Media Pioneer Robot

    Directory of Open Access Journals (Sweden)

    S. Parasuraman, V.Ganapathy

    2012-10-01

    Full Text Available A key issue in the research of an autonomous robot is the design and development of the navigation technique that enables the robot to navigate in a real world environment. In this research, the issues investigated and methodologies established include (a Designing of the individual behavior and behavior rule selection using Alpha level fuzzy logic system  (b Designing of the controller, which maps the sensors input to the motor output through model based Fuzzy Logic Inference System and (c Formulation of the decision-making process by using Alpha-level fuzzy logic system. The proposed method is applied to Active Media Pioneer Robot and the results are discussed and compared with most accepted methods. This approach provides a formal methodology for representing and implementing the human expert heuristic knowledge and perception-based action in mobile robot navigation. In this approach, the operational strategies of the human expert driver are transferred via fuzzy logic to the robot navigation in the form of a set of simple conditional statements composed of linguistic variables.Keywards: Mobile robot, behavior based control, fuzzy logic, alpha level fuzzy logic, obstacle avoidance behavior and goal seek behavior

  18. Anti-tumor Effects of Plasma Activated Media and Correlation with Hydrogen Peroxide Concentration

    Science.gov (United States)

    Laroussi, Mounir; Mohades, Soheila; Barekzi, Nazir; Maruthamuthu, Venkat; Razavi, Hamid

    2016-09-01

    Plasma activated media (PAM) can induce death in cancer cells. In our research, PAM is produced by exposing liquid culture medium to a helium plasma pencil. Reactive oxygen and nitrogen species in the aqueous state are known factors in anti-tumor effects of PAM. The duration of plasma exposure determines the concentrations of reactive species produced in PAM. Stability of the plasma generated reactive species and their lifetime depend on parameters such as the chemical composition of the medium. Here, a complete cell culture medium was employed to make PAM. Later, PAM was used to treat SCaBER cancer cells either as an immediate PAM (right after exposure) or as an aged-PAM (after storage). SCaBER (ATCC®HTB-3™) is an epithelial cell line from a human bladder with the squamous carcinoma disease. A normal epithelial cell line from a kidney tissue of a dog - MDCK (ATCC®CCL-34™) - was used to analyze the selective effect of PAM. Correspondingly, we measured the concentration of hydrogen peroxide- as a stable species with biological impact on cell viability- in both immediate PAM and aged-PAM. In addition, we report on the effect of serum supplemented in PAM on the H2O2 concentration measured by Amplex red assay kit. Finally, we evaluate the effects of PAM on growth and morphological changes in MDCK cells using fluorescence microscopy.

  19. Nerve transection repair using laser-activated chitosan in a rat model.

    Science.gov (United States)

    Bhatt, Neel K; Khan, Taleef R; Mejias, Christopher; Paniello, Randal C

    2017-08-01

    Cranial nerve transection during head and neck surgery is conventionally repaired with microsuture. Previous studies have demonstrated recovery with laser nerve welding (LNW), a novel alternative to microsuture. LNW has been reported to have poorer tensile strength, however. Laser-activated chitosan, an adhesive biopolymer, may promote nerve recovery while enhancing the tensile strength of the repair. Using a rat posterior tibial nerve injury model, we compared four different methods of nerve repair in this pilot study. Animal study. Animals underwent unilateral posterior tibial nerve transection. The injury was repaired by potassium titanyl phosphate (KTP) laser alone (n = 20), KTP + chitosan (n = 12), microsuture + chitosan (n = 12), and chitosan alone (n = 14). Weekly walking tracks were conducted to measure functional recovery (FR). Tensile strength (TS) was measured at 6 weeks. At 6 weeks, KTP laser alone had the best recovery (FR = 93.4% ± 8.3%). Microsuture + chitosan, KTP + chitosan, and chitosan alone all showed good FR (87.4% ± 13.5%, 84.6% ± 13.0%, and 84.1% ± 10.0%, respectively). One-way analysis of variance was performed (F(3,56) = 2.6, P = .061). A TS threshold of 3.8 N was selected as a control mean recovery. Three groups-KTP alone, KTP + chitosan, and microsuture + chitosan-were found to meet threshold 60% (95% confidence interval [CI]: 23.1%-88.3%), 75% (95% CI: 46.8%-91.1%), and 100% (95% CI: 75.8%-100.0%), respectively. In the posterior tibial nerve model, all repair methods promoted nerve recovery. Laser-activated chitosan as a biopolymer anchor provided good TS and appears to be a novel alternative to microsuture. This repair method may have surgical utility following cranial nerve injury during head and neck surgery. NA Laryngoscope, 127:E253-E257, 2017. © 2017 The American Laryngological, Rhinological and Otological Society, Inc.

  20. Antimicrobial activity of biopolymer–antibiotic thin films fabricated by advanced pulsed laser methods

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Popescu, C.; Dorcioman, G.; Miroiu, F.M.; Socol, G.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Gittard, S.D.; Miller, P.R.; Narayan, R.J. [Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, NC 27599-7575 (United States); Enculescu, M. [National Institute for Materials Physics, PO Box MG-7, Bucharest-Magurele (Romania); Chrisey, D.B. [Tulane University, Department of Physics and Engineering Physics, New Orleans, LA (United States)

    2013-08-01

    We report on thin film deposition by matrix assisted pulsed laser evaporation (MAPLE) of two polymer–drug composite thin film systems. A pulsed KrF* excimer laser source (λ = 248 nm, τ = 25 ns, ν = 10 Hz) was used to deposit composite thin films of poly(D,L-lactide) (PDLLA) containing several gentamicin concentrations. FTIR spectroscopy was used to demonstrate that MAPLE-transferred materials exhibited chemical structures similar to those of drop cast materials. Scanning electron microscopy data indicated that MAPLE may be used to fabricate thin films of good morphological quality. The activity of PDLLA–gentamicin composite thin films against Staphylococcus aureus bacteria was demonstrated using drop testing. The influence of drug concentration on microbial viability was also assessed. Our studies indicate that polymer–drug composite thin films prepared by MAPLE may be used to impart antimicrobial activity to implants, medical devices, and other contact surfaces.

  1. Nutrient removal using biosorption activated media: Preliminary biogeochemical assessment of an innovative stormwater infiltration basin

    International Nuclear Information System (INIS)

    O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G.

    2012-01-01

    Soil beneath a stormwater infiltration basin receiving runoff from a 23 ha predominantly residential watershed in north-central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop an innovative stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO 3 − /Cl − ) ratios for the shallow groundwater indicates that prior to using BAM, NO 3 − concentrations were substantially influenced by nitrification or variations in NO 3 − input. In contrast, for the new basin utilizing BAM, NO 3 − /Cl − ratios indicate minor nitrification and NO 3 − losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest that NO 3 − losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by the increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO 4 3− ) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO 4 3− /Cl − ratios for shallow

  2. Microbial Activity and Precipitation at Solution-Solution Mixing Zones in Porous Media -- Subsurface Biogeochemical Research

    Energy Technology Data Exchange (ETDEWEB)

    Colwell, Frederick [Oregon State Univ., Corvallis, OR (United States); Wildenschild, Dorthe [Oregon State Univ., Corvallis, OR (United States); Wood, Brian [Oregon State Univ., Corvallis, OR (United States); Gerlach, Robin [Montana State Univ., Bozeman, MT (United States); Mitchell, Andrew [Montana State Univ., Bozeman, MT (United States); Redden, George [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-08-29

    The goal for this research was to understand how best to add compounds to receptive microbial communities in porous media in order to achieve optimal calcite precipitation in a volumetrically significant space and to understand the physiological health of the cells that are responsible for the calcite precipitation. The specific objectives were to: (1) develop better tools for visually examining biofilms in porous media and calcium carbonate precipitation being mediated by microbes in porous media, and (2) demonstrate the effectiveness of using that tool within a flow cell model system.

  3. Deactivation of solid catalysts in liquid media: the case of leaching of active sites in biomass conversion reactions

    DEFF Research Database (Denmark)

    Sádaba, Irantzu; Lopez Granados, Manuel; Riisager, Anders

    2015-01-01

    This review is aimed to be a brief tutorial covering the deactivation of solid catalysts in the liquid phase, with specific focus on leaching, which can be especially helpful to researchers not familiarized with catalytic processes in the liquid phase. Leaching refers to the loss of active species....... However, as a consequence of the development of new processes for biorefineries, an increasing number of reactions deal with liquid media, and thus, the stability and reusability of a solid catalyst in this situation represent a huge challenge that requires specific attention. Leaching of active phases...... is particularly problematic because of its irreversibility and it can be one of the main causes of catalyst deactivation in liquid media, threatening the sustainability of the process. This tutorial review presents a survey of the main aspects concerning the deactivation due to leaching of active species from...

  4. Functional characterization of planar sensors with active edges using laser and X-ray beam scans

    International Nuclear Information System (INIS)

    Povoli, M.; Bagolini, A.; Boscardin, M.; Dalla Betta, G.-F.; Giacomini, G.; Hasi, J.; Oh, A.; Zorzi, N.

    2013-01-01

    We report on the functional characterization of planar sensors with active edges fabricated at Fondazione Bruno Kessler (FBK), Trento, Italy. The measurements here reported were performed by means of laser and X-ray beam scans mainly focusing on the signal efficiency of the edge region of the devices. Results are very encouraging and show very good sensitivity up to few microns away from the device physical edge

  5. Functional characterization of planar sensors with active edges using laser and X-ray beam scans

    Energy Technology Data Exchange (ETDEWEB)

    Povoli, M., E-mail: povoli@disi.unitn.it [Dipartimento di Ingegneria e Scienza dell' Informazione, Università di Trento, Via Sommarive, 14, I-38123 Povo di Trento (Italy); INFN, Sezione di Padova (Gruppo Collegato di Trento),Via Sommarive, 14, I-38123 Povo di Trento (Italy); Bagolini, A.; Boscardin, M. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive, 18, I-38123 Povo di Trento (Italy); Dalla Betta, G.-F. [Dipartimento di Ingegneria e Scienza dell' Informazione, Università di Trento, Via Sommarive, 14, I-38123 Povo di Trento (Italy); INFN, Sezione di Padova (Gruppo Collegato di Trento),Via Sommarive, 14, I-38123 Povo di Trento (Italy); Giacomini, G. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive, 18, I-38123 Povo di Trento (Italy); Hasi, J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025-7015 (United States); Oh, A. [The University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); Zorzi, N. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi (FBK-CMM), Via Sommarive, 18, I-38123 Povo di Trento (Italy)

    2013-08-01

    We report on the functional characterization of planar sensors with active edges fabricated at Fondazione Bruno Kessler (FBK), Trento, Italy. The measurements here reported were performed by means of laser and X-ray beam scans mainly focusing on the signal efficiency of the edge region of the devices. Results are very encouraging and show very good sensitivity up to few microns away from the device physical edge.

  6. Examining the use of evidence-based and social media supported tools in freely accessible physical activity intervention websites.

    Science.gov (United States)

    Vandelanotte, Corneel; Kirwan, Morwenna; Rebar, Amanda; Alley, Stephanie; Short, Camille; Fallon, Luke; Buzza, Gavin; Schoeppe, Stephanie; Maher, Carol; Duncan, Mitch J

    2014-08-17

    It has been shown that physical activity is more likely to increase if web-based interventions apply evidence-based components (e.g. self-monitoring) and incorporate interactive social media applications (e.g. social networking), but it is unclear to what extent these are being utilized in the publicly available web-based physical activity interventions. The purpose of this study was to evaluate whether freely accessible websites delivering physical activity interventions use evidence-based behavior change techniques and provide social media applications. In 2013, a systematic search strategy examined 750 websites. Data was extracted on a wide range of variables (e.g. self-monitoring, goal setting, and social media applications). To evaluate website quality a new tool, comprising three sub-scores (Behavioral Components, Interactivity and User Generated Content), was developed to assess implementation of behavior change techniques and social media applications. An overall website quality scored was obtained by summing the three sub-scores. Forty-six publicly available websites were included in the study. The use of self-monitoring (54.3%), goal setting (41.3%) and provision of feedback (46%) was relatively low given the amount of evidence supporting these features. Whereas the presence of features allowing users to generate content (73.9%), and social media components (Facebook (65.2%), Twitter (47.8%), YouTube (48.7%), smartphone applications (34.8%)) was relatively high considering their innovative and untested nature. Nearly all websites applied some behavioral and social media applications. The average Behavioral Components score was 3.45 (±2.53) out of 10. The average Interactivity score was 3.57 (±2.16) out of 10. The average User Generated Content Score was 4.02 (±2.77) out of 10. The average overall website quality score was 11.04 (±6.92) out of 30. Four websites (8.7%) were classified as high quality, 12 websites (26.1%) were classified as moderate

  7. Scattering of light passing through a statistically rough interface between media with different refractive indices after laser correction of vision

    Energy Technology Data Exchange (ETDEWEB)

    Semchishen, A V; Seminogov, V N; Semchishen, V A [Institute of Laser and Information Technologies, Russian Academy of Sciences, Troitsk, Moscow Region (Russian Federation)

    2012-04-30

    Forward scattering of light passing through large-scale irregularities of the interface between two media having different refractive indices is considered. An analytical expression for the ratio of intensities of directional and diffusion components of scattered light in the far-field zone is derived. It is theoretically shown that the critical depth of possible interface relief irregularities, starting from which the intensity of the diffuse component in the passing light flow becomes comparable with the directional light component, responsible for the image formation on the eye retina, is 3 - 4 {mu}m, with the increase in the refractive index in the postoperational zone taken into account. These profile depth values agree with the experimentally measured ones and may affect the contrast sensitivity of vision.

  8. Scattering of light passing through a statistically rough interface between media with different refractive indices after laser correction of vision

    International Nuclear Information System (INIS)

    Semchishen, A V; Seminogov, V N; Semchishen, V A

    2012-01-01

    Forward scattering of light passing through large-scale irregularities of the interface between two media having different refractive indices is considered. An analytical expression for the ratio of intensities of directional and diffusion components of scattered light in the far-field zone is derived. It is theoretically shown that the critical depth of possible interface relief irregularities, starting from which the intensity of the diffuse component in the passing light flow becomes comparable with the directional light component, responsible for the image formation on the eye retina, is 3 - 4 μm, with the increase in the refractive index in the postoperational zone taken into account. These profile depth values agree with the experimentally measured ones and may affect the contrast sensitivity of vision.

  9. Optimization of end-pumped, actively Q-switched quasi-III-level lasers.

    Science.gov (United States)

    Jabczynski, Jan K; Gorajek, Lukasz; Kwiatkowski, Jacek; Kaskow, Mateusz; Zendzian, Waldemar

    2011-08-15

    The new model of end-pumped quasi-III-level laser considering transient pumping processes, ground-state-depletion and up-conversion effects was developed. The model consists of two parts: pumping stage and Q-switched part, which can be separated in a case of active Q-switching regime. For pumping stage the semi-analytical model was developed, enabling the calculations for final occupation of upper laser level for given pump power and duration, spatial profile of pump beam, length and dopant level of gain medium. For quasi-stationary inversion, the optimization procedure of Q-switching regime based on Lagrange multiplier technique was developed. The new approach for optimization of CW regime of quasi-three-level lasers was developed to optimize the Q-switched lasers operating with high repetition rates. Both methods of optimizations enable calculation of optimal absorbance of gain medium and output losses for given pump rate. © 2011 Optical Society of America

  10. Pulsed laser activated cell sorter (PLACS) for high-throughput fluorescent mammalian cell sorting

    Science.gov (United States)

    Chen, Yue; Wu, Ting-Hsiang; Chung, Aram; Kung, Yu-Chung; Teitell, Michael A.; Di Carlo, Dino; Chiou, Pei-Yu

    2014-09-01

    We present a Pulsed Laser Activated Cell Sorter (PLACS) realized by exciting laser induced cavitation bubbles in a PDMS microfluidic channel to create high speed liquid jets to deflect detected fluorescent samples for high speed sorting. Pulse laser triggered cavitation bubbles can expand in few microseconds and provide a pressure higher than tens of MPa for fluid perturbation near the focused spot. This ultrafast switching mechanism has a complete on-off cycle less than 20 μsec. Two approaches have been utilized to achieve 3D sample focusing in PLACS. One is relying on multilayer PDMS channels to provide 3D hydrodynamic sheath flows. It offers accurate timing control of fast (2 m sec-1) passing particles so that synchronization with laser bubble excitation is possible, an critically important factor for high purity and high throughput sorting. PLACS with 3D hydrodynamic focusing is capable of sorting at 11,000 cells/sec with >95% purity, and 45,000 cells/sec with 45% purity using a single channel in a single step. We have also demonstrated 3D focusing using inertial flows in PLACS. This sheathless focusing approach requires 10 times lower initial cell concentration than that in sheath-based focusing and avoids severe sample dilution from high volume sheath flows. Inertia PLACS is capable of sorting at 10,000 particles sec-1 with >90% sort purity.

  11. Relationships between abstract features and methodological quality explained variations of social media activity derived from systematic reviews about psoriasis interventions.

    Science.gov (United States)

    Ruano, J; Aguilar-Luque, M; Isla-Tejera, B; Alcalde-Mellado, P; Gay-Mimbrera, J; Hernandez-Romero, José Luis; Sanz-Cabanillas, J L; Maestre-López, B; González-Padilla, M; Carmona-Fernández, P J; Gómez-García, F; García-Nieto, A Vélez

    2018-05-24

    The aim of this study was to describe the relationship among abstract structure, readability, and completeness, and how these features may influence social media activity and bibliometric results, considering systematic reviews (SRs) about interventions in psoriasis classified by methodological quality. Systematic literature searches about psoriasis interventions were undertaken on relevant databases. For each review, methodological quality was evaluated using the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) tool. Abstract extension, structure, readability, and quality and completeness of reporting were analyzed. Social media activity, which consider Twitter and Facebook mention counts, as well as Mendeley readers and Google scholar citations were obtained for each article. Analyses were conducted to describe any potential influence of abstract characteristics on review's social media diffusion. We classified 139 intervention SRs as displaying high/moderate/low methodological quality. We observed that abstract readability of SRs has been maintained high for last 20 years, although there are some differences based on their methodological quality. Free-format abstracts were most sensitive to the increase of text readability as compared with more structured abstracts (IMRAD or 8-headings), yielding opposite effects on their quality and completeness depending on the methodological quality: a worsening in low quality reviews and an improvement in those of high-quality. Both readability indices and PRISMA for Abstract total scores showed an inverse relationship with social media activity and bibliometric results in high methodological quality reviews but not in those of lower quality. Our results suggest that increasing abstract readability must be specially considered when writing free-format summaries of high-quality reviews, because this fact correlates with an improvement of their completeness and quality, and this may help to achieve broader

  12. Antibacterial activity of magnetic iron oxide nanoparticles synthesized by laser ablation in liquid

    International Nuclear Information System (INIS)

    Ismail, Raid A.; Sulaiman, Ghassan M.; Abdulrahman, Safa A.; Marzoog, Thorria R.

    2015-01-01

    In this study, (50–110 nm) magnetic iron oxide (α-Fe 2 O 3 ) nanoparticles were synthesized by pulsed laser ablation of iron target in dimethylformamide (DMF) and sodium dodecyl sulfate (SDS) solutions. The structural properties of the synthesized nanoparticles were investigated by using Fourier Transform Infrared (FT-IR) spectroscopy, UV–VIS absorption, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The effect of laser fluence on the characteristics of these nanoparticles was studied. Antibacterial activities of iron oxide nanoparticles were tested against Gram-positive; Staphylococcus aureus and Gram-negative; Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens. The results showed a noteworthy inhibition on both bacterial strains. The preparation conditions were found to affect significantly the antibacterial activity of these nanoparticles. The synthesized magnetic nanoparticles were used to capture rapidly S. aureus bacteria under the magnetic field effect. - Highlights: • Synthesis magnetic iron oxide nanoparticles by pulsed laser ablation • Antibacterial activity against Gram-positive and Gram-negative bacteria • Captured magnetic nanoparticles by S. aureus bacteria under effect of magnetic field

  13. Active iris vascular tufts bleeding successfully treated with argon laser photocoagulation.

    Science.gov (United States)

    Sarmad, Ambreen; Alfaqawi, Fadi; Chakrabarti, Monali; Mitra, Arijit; Mushtaq, Bushra

    2018-03-01

    Iris vascular tufts (IVT) are rare biomicroscopic capillary outgrowths from the pupillary margins. Patients are usually asymptomatic until presenting with blurred vision due to spontaneous hyphema or with raised intraocular pressure. A 61-year-old woman presented to eye casualty with left eye (LE) blurred vision and discomfort for 1 day. Her external ocular examination was unremarkable and visual acuity was 6/6 in the right eye (RE) and 6/9 in the LE. Biomicroscopic examination revealed a 2-mm hyphema in her LE and bilateral multiple small IVT and active bleeding from IVT at the pupillary margin of the LE at the 5 o'clock position. Diagnosis of LE active bleeding from IVT was made and she underwent argon laser photocoagulation directed at the source of bleeding. The bleeding stopped immediately after the second burn. She was followed up for 3 months; her visual acuity was 6/5 and 6/6 in the RE and LE, respectively, with no further problems. Iris vascular tufts are benign and recurrent hemorrhages are unlikely. Therefore, definitive argon laser photocoagulation or surgical treatment are reserved to arrest further episodes of hyphema. Our case demonstrates the effective use of argon laser photocoagulation to completely arrest active bleeding from IVT and excellent recovery of hyphema with no further problems for 5 years.

  14. Reinforcement of high-risk anastomoses using laser-activated protein solders: a clinical study

    Science.gov (United States)

    Libutti, Steven K.; Bessler, Marc; Chabot, J.; Bass, Lawrence S.; Oz, Mehmet C.; Auteri, Joseph S.; Kirsch, Andrew J.; Nowygrod, Roman; Treat, Michael R.

    1993-07-01

    Anastomotic leakage or breakdown can result in catastrophic complications and significantly increased post-operative morbidity and mortality. Certain anastomoses are subject to a higher incidence of disruption and are therefore termed high risk. In an attempt to decrease the risk of anastomotic leaks, we reinforced sutured anastomoses with a laser activated protein solder in patients undergoing esophagojejunostomies (n equals 2), lung transplantation (n equals 2), and pancreaticojejunostomies (Whipple procedure, n equals 5). The protein solder was composed of 1.0 ml of a 25% human albumin solution, 1.0 ml of sodium hyaluronate, and 0.1 ml of Cardiogreen dye. This composition was applied to the sutured anastomosis and activated with an 860 nm pulsed diode laser. Drains were placed when appropriate and patients were followed for up to 10 months post-operatively and assessed for clinical signs of anastomotic leaks. Results to data demonstrated that there were no immediate complications as a result of the procedure. Operative time was not significantly lengthened. There were no cases of clinically significant leakage from any of the reinforced anastomoses. Laser activated protein solders may help to reduce the incidence of leakage in high risk anastomoses. Large numbers of patients and longer follow-up is needed however, to draw significant conclusions.

  15. Antibacterial activity of magnetic iron oxide nanoparticles synthesized by laser ablation in liquid

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Raid A., E-mail: raidismail@yahoo.com [Laser Physics Division, Applied Science Department, University of Technology, Baghdad (Iraq); Sulaiman, Ghassan M. [Biotechnology Division, Applied Science Department, University of Technology, Baghdad (Iraq); Abdulrahman, Safa A. [Laser Physics Division, Applied Science Department, University of Technology, Baghdad (Iraq); Marzoog, Thorria R. [Biotechnology Division, Applied Science Department, University of Technology, Baghdad (Iraq)

    2015-08-01

    In this study, (50–110 nm) magnetic iron oxide (α-Fe{sub 2}O{sub 3}) nanoparticles were synthesized by pulsed laser ablation of iron target in dimethylformamide (DMF) and sodium dodecyl sulfate (SDS) solutions. The structural properties of the synthesized nanoparticles were investigated by using Fourier Transform Infrared (FT-IR) spectroscopy, UV–VIS absorption, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD). The effect of laser fluence on the characteristics of these nanoparticles was studied. Antibacterial activities of iron oxide nanoparticles were tested against Gram-positive; Staphylococcus aureus and Gram-negative; Escherichia coli, Pseudomonas aeruginosa and Serratia marcescens. The results showed a noteworthy inhibition on both bacterial strains. The preparation conditions were found to affect significantly the antibacterial activity of these nanoparticles. The synthesized magnetic nanoparticles were used to capture rapidly S. aureus bacteria under the magnetic field effect. - Highlights: • Synthesis magnetic iron oxide nanoparticles by pulsed laser ablation • Antibacterial activity against Gram-positive and Gram-negative bacteria • Captured magnetic nanoparticles by S. aureus bacteria under effect of magnetic field.

  16. Lewis Acid Pairs for the Activation of Biomass-derived Oxygenates in Aqueous Media

    Energy Technology Data Exchange (ETDEWEB)

    Roman, Yuriy [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2015-09-14

    The objective of this project is to understand the mechanistic aspects behind the cooperative activation of oxygenates by catalytic pairs in aqueous media. Specifically, we will investigate how the reactivity of a solid Lewis acid can be modulated by pairing the active site with other catalytic sites at the molecular level, with the ultimate goal of enhancing activation of targeted functional groups. Although unusual catalytic properties have been attributed to the cooperative effects promoted by such catalytic pairs, virtually no studies exist detailing the use heterogeneous water-tolerant Lewis pairs. A main goal of this work is to devise rational pathways for the synthesis of porous heterogeneous catalysts featuring isolated Lewis pairs that are active in the transformation of biomass-derived oxygenates in the presence of bulk water. Achieving this technical goal will require closely linking advanced synthesis techniques; detailed kinetic and mechanistic investigations; strict thermodynamic arguments; and comprehensive characterization studies of both materials and reaction intermediates. For the last performance period (2014-2015), two technical aims were pursued: 1) C-C coupling using Lewis acid and base pairs in Lewis acidic zeolites. Tin-, zirconium-, and hafnium containing zeolites (e.g., Sn-, Zr-, and Hf-Beta) are versatile solid Lewis acids that selectively activate carbonyl functional groups. In this aim, we demonstrate that these zeolites catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through α-proton abstraction. The Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions. 2) One-pot synthesis of MWW zeolite nanosheets for activation of bulky substrates. Through

  17. Dissipative Structures At Laser-Solid Interactions

    Science.gov (United States)

    Nanai, Laszlo

    1989-05-01

    The questions which are discussed in this lecture refer to one of sections of laser-solid interactions, namely: to formation of different dissipative structures on the surface of metals and semiconductors when they are irradiated by intensive laser light in chemically active media (f.e.air). Some particular examples of the development at different spatial and time instabilities, periodic and stochastic structures, auto-wave processes are present-ed using testing materials vanadium metal and semiconducting V205 single crystals and light sources: cw and pulsed CO2 and YAG lasers.

  18. Activation of NLRP3 inflammasome in human middle ear cholesteatoma and chronic otitis media.

    Science.gov (United States)

    Kariya, Shin; Okano, Mitsuhiro; Zhao, Pengfei; Kataoka, Yuko; Yoshinobu, Junko; Maeda, Yukihide; Ishihara, Hisashi; Higaki, Takaya; Nishizaki, Kazunori

    2016-01-01

    The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome plays an important role in the pathogenesis of middle ear diseases. Modulation of inflammasome-mediated inflammation may be a novel therapeutic strategy for cholesteatoma and chronic otitis media. NLRP3 inflammasome is a critical molecule mediating interleukin (IL)-1β responses. However, the expression of NLRP3 in the pathogenesis of cholesteatoma and chronic otitis media has not been fully examined. This study sought to assess the expression of NLRP3, ASC (apoptosis-associated speck-like protein containing a caspase recruitment domain and a pyrin domain), and caspase-1 in middle ear tissues in patients with cholesteatoma or chronic otitis media. Middle ear tissue samples were obtained from patients with cholesteatoma or chronic otitis media. Control middle ear samples were collected during cochlear implant surgery of patients without middle ear inflammation. The expression of NLRP3, ASC, and caspase-1 were examined by reverse transcription polymerase chain reaction (RT-PCR) assay and immunohistochemical study. The levels of mRNA of NLRP3, ASC, and caspase-1 were significantly elevated in cholesteatoma and chronic otitis media as compared with that of normal controls. The proteins of NLRP3, ASC, and caspase-1 were observed in infiltrating inflammatory cells in cholesteatoma and chronic otitis media.

  19. Illumination Effect of Laser Light in Foggy Objects Using an Active Imaging System

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Seong-Ouk; Park, Seung-Kyu; Ahn, Yong-Jin; Baik, Sung-Hoon; Choi, Young-Soo; Jeong, Kyung-Min [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    Active imaging techniques usually provide improved image information when compared to passive imaging techniques. Active vision is a direct visualization technique using an artificial illuminant. Range-gated imaging (RGI) technique is one of active vision technologies. The RGI technique extracts vision information by summing time sliced vision images. In the RGI system, objects are illuminated for ultra-short time by a high intensity illuminant and then the light reflected from objects is captured by a highly sensitive image sensor with the exposure of ultra-short time. The Range-gated imaging is an emerging technology in the field of surveillance for security application, especially in the visualization of darken night or foggy environment. Although RGI viewing was discovered in the 1960's, this technology is currently more applicable by virtue of the rapid development of optical and sensor technologies, such as highly sensitive imaging sensor and ultra-short pulse laser light. Especially, this system can be adopted in robot-vision system by virtue of the compact system configuration. During the past decades, several applications of this technology have been applied in target recognition and in harsh environments, such as fog, underwater vision. Also, this technology has been demonstrated range imaging based on range-gated imaging. Laser light having a short pulse width is usually used for the range-gated imaging system. In this paper, an illumination effect of laser light in foggy objects is studied using a range-gated imaging system. The used imaging system consists of an ultra-short pulse (0.35 ns) laser light and a gated imaging sensor. The experiment is carried out to monitor objects in a box filled by fog. In this paper, the effects by fog particles in range-gated imaging technique are studied. Edge blurring and range distortion are the generated by fog particles.

  20. Illumination Effect of Laser Light in Foggy Objects Using an Active Imaging System

    International Nuclear Information System (INIS)

    Kwon, Seong-Ouk; Park, Seung-Kyu; Ahn, Yong-Jin; Baik, Sung-Hoon; Choi, Young-Soo; Jeong, Kyung-Min

    2015-01-01

    Active imaging techniques usually provide improved image information when compared to passive imaging techniques. Active vision is a direct visualization technique using an artificial illuminant. Range-gated imaging (RGI) technique is one of active vision technologies. The RGI technique extracts vision information by summing time sliced vision images. In the RGI system, objects are illuminated for ultra-short time by a high intensity illuminant and then the light reflected from objects is captured by a highly sensitive image sensor with the exposure of ultra-short time. The Range-gated imaging is an emerging technology in the field of surveillance for security application, especially in the visualization of darken night or foggy environment. Although RGI viewing was discovered in the 1960's, this technology is currently more applicable by virtue of the rapid development of optical and sensor technologies, such as highly sensitive imaging sensor and ultra-short pulse laser light. Especially, this system can be adopted in robot-vision system by virtue of the compact system configuration. During the past decades, several applications of this technology have been applied in target recognition and in harsh environments, such as fog, underwater vision. Also, this technology has been demonstrated range imaging based on range-gated imaging. Laser light having a short pulse width is usually used for the range-gated imaging system. In this paper, an illumination effect of laser light in foggy objects is studied using a range-gated imaging system. The used imaging system consists of an ultra-short pulse (0.35 ns) laser light and a gated imaging sensor. The experiment is carried out to monitor objects in a box filled by fog. In this paper, the effects by fog particles in range-gated imaging technique are studied. Edge blurring and range distortion are the generated by fog particles

  1. Nutrient removal using biosorption activated media: preliminary biogeochemical assessment of an innovative stormwater infiltration basin

    Science.gov (United States)

    O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Xuan, Zhemin; Harris, Willie G.

    2012-01-01

    Soil beneath a stormwater infiltration basin receiving runoff from a 22.7 ha predominantly residential watershed in central Florida, USA, was amended using biosorption activated media (BAM) to study the effectiveness of this technology in reducing inputs of nitrogen and phosphorus to groundwater. The functionalized soil amendment BAM consists of a 1.0:1.9:4.1 mixture (by volume) of tire crumb (to increase sorption capacity), silt and clay (to increase soil moisture retention), and sand (to promote sufficient infiltration), which was applied to develop a prototype stormwater infiltration basin utilizing nutrient reduction and flood control sub-basins. Comparison of nitrate/chloride (NO3-/Cl-) ratios for the shallow groundwater indicate that prior to using BAM, NO3- concentrations were substantially influenced by nitrification or variations in NO3- input. In contrast, for the prototype basin utilizing BAM, NO3-/Cl- ratios indicate minor nitrification and NO3- losses with the exception of one summer sample that indicated a 45% loss. Biogeochemical indicators (denitrifier activity derived from real-time polymerase chain reaction and variations in major ions, nutrients, dissolved and soil gases, and stable isotopes) suggest NO3- losses are primarily attributable to denitrification, whereas dissimilatory nitrate reduction to ammonium is a minor process. Denitrification was likely occurring intermittently in anoxic microsites in the unsaturated zone, which was enhanced by increased soil moisture within the BAM layer and resultant reductions in surface/subsurface oxygen exchange that produced conditions conducive to increased denitrifier activity. Concentrations of total dissolved phosphorus and orthophosphate (PO43-) were reduced by more than 70% in unsaturated zone soil water, with the largest decreases in the BAM layer where sorption was the most likely mechanism for removal. Post-BAM PO43-/Cl- ratios for shallow groundwater indicate predominantly minor increases and

  2. Effect of the physical properties of activated carbon in the gold adsorption from cyanide media

    International Nuclear Information System (INIS)

    Navarro, P.; Vargas, C.

    2010-01-01

    The effect of the physical properties of an activated carbon such as pore size distribution, specific surface, pore average diameter, in the gold adsorption from cyanide solution with the gold to the Au (CN) - 2 form, was studied. To meet the proposed objectives two carbons were studied: carbon A with specific surface of 985 m 2 / g, 57 % of micropores and 1.85 nm as average diameter of pores and carbon B with specific surface of 786 m 2 / g, 27 % and pores of 2.35 nm as average diameter of pores; both granular carbons made from coconut shell. Batch adsorption tests were performed in a reactor of 500 ml of capacity with mechanical stirring at constant temperature. The effect of cations present in the aqueous solutions such as Ca 2 +, Na+, K+ and Li+, the effect of pore size distribution, the effect of average pore diameter and surface area were evaluated in function of the rate and amount of gold adsorbed on the activated carbons denominated as A and B. The results to indicate that the physical properties of an activated carbon are an important factor in the gold adsorption process in terms of rate and amount of adsorbed gold. The carbon B with 786 m 2 / g of specific surface area reached a higher load per unit area (0.02 mg Au/m 2 ) in relation to the carbon B of 985 m 2 / g which had a load of 0.01 mg Au / m 2 , after 6 h of contact carbon-solution. The rate adsorption of gold in both carbons is controlled by mass transfer in the liquid film surrounding the carbon particles to short times or small loads of gold in the particles, far from equilibrium. Applying a first order kinetic model, it was obtained that the ratio of the kinetic constants for carbons A and B, ie (kB / kA), fluctuates in a value of 3 for the different cations in study. In general it is possible to say that the rate adsorption and the amount of adsorbed gold increased with the increase in macropores and with the increasing pore average diameter. The presence of cations favors the gold

  3. Waveguide and active region structure optimization for low-divergence InAs/InGaAs quantum dot comb lasers

    Science.gov (United States)

    Korenev, Vladimir V.; Savelyev, Artem V.; Zhukov, Alexey E.; Maximov, Mikhail V.; Omelchenko, Alexander V.

    2015-05-01

    Ways to improve beam divergence and energy consumption of quantum dot lasers emitting via the ground-state optical transitions by optimization of the key parameters of laser active region are discussed. It is shown that there exist an optimal cavity length, dispersion of inhomogeneous broadening and number of QD layers in active region allowing to obtain lasing spectrum of a given width at minimum injection current. The planar dielectric waveguide of the laser is optimized by analytical means for a better trade-off between high Γ-factor and low beam divergence.

  4. Numerical Simulation of Damage during Forging with Superimposed Hydrostatic Pressure by Active Media

    International Nuclear Information System (INIS)

    Behrens, B.-A.; Hagen, T.; Roehr, S.; Sidhu, K. B.

    2007-01-01

    The effective reduction of energy consumption and a reasonable treatment of resources can be achieved by minimizing a component's weight using lightweight metals. In this context, aluminum alloys play a major role. Due to their material-sided restricted formability, the mentioned aluminum materials are difficult to form. The plasticity of a material is ascertained by its maximum forming limit. It is attained, when the deformation causes mechanical damage within the material. Damage of that sort is reached more rapidly, the greater the tensile strength rate in relation to total tension rate. A promising approach of handling these low ductile, high-strength aluminum alloys within a forming process, is forming with a synchronized superposition of comprehensive stress by active media such as by controlling oil pressure. The influence of superimposed hydrostatic pressure on the flow stress was analyzed as well as the formability for different procedures at different hydrostatic pressures and temperature levels. It was observed that flow stress is independent of superimposed hydrostatic pressure. Neither the superimposed pressure has an influence on the plastic deformation, nor does a pressure dependent material hardening due to increasing hydrostatic pressure take place. The formability increases with rising hydrostatic pressure. The relative gain at room temperature and increase of the superimposed pressure from 0 to 600 bar for tested materials was at least 140 % and max. 220 %. Therefore in this paper, based on these experimental observations, it is the intended to develop a numerical simulation in order to predict ductile damage that occurs in the bulk forging process with superimposed hydrostatic pressure based Lemaitre's damage model

  5. The impact of media campaigns on smoking cessation activity: a structural vector autoregression analysis.

    Science.gov (United States)

    Langley, Tessa E; McNeill, Ann; Lewis, Sarah; Szatkowski, Lisa; Quinn, Casey

    2012-11-01

    To evaluate the effect of tobacco control media campaigns and pharmaceutical company-funded advertising for nicotine replacement therapy (NRT) on smoking cessation activity. Multiple time series analysis using structural vector autoregression, January 2002-May 2010. England and Wales. Tobacco control campaign data from the Central Office of Information; commercial NRT campaign data; data on calls to the National Health Service (NHS) stop smoking helpline from the Department of Health; point-of-sale data on over-the-counter (OTC) sales of NRT; and prescribing data from The Health Improvement Network (THIN), a database of UK primary care records. Monthly calls to the NHS stop smoking helpline and monthly rates of OTC sales and prescribing of NRT. A 1% increase in tobacco control television ratings (TVRs), a standard measure of advertising exposure, was associated with a statistically significant 0.085% increase in calls in the same month (P = 0.007), and no statistically significant effect in subsequent months. Tobacco control TVRs were not associated with OTC NRT sales or prescribed NRT. NRT advertising TVRs had a significant effect on NRT sales which became non-significant in the seasonally adjusted model, and no significant effect on prescribing or calls. Tobacco control campaigns appear to be more effective at triggering quitting behaviour than pharmaceutical company NRT campaigns. Any effect of such campaigns on quitting behaviour seems to be restricted to the month of the campaign, suggesting that such campaigns need to be sustained over time. © 2012 The Authors, Addiction © 2012 Society for the Study of Addiction.

  6. Generation of picosecond pulses and frequency combs in actively mode locked external ring cavity quantum cascade lasers

    International Nuclear Information System (INIS)

    Wójcik, Aleksander K.; Belyanin, Alexey; Malara, Pietro; Blanchard, Romain; Mansuripur, Tobias S.; Capasso, Federico

    2013-01-01

    We propose a robust and reliable method of active mode locking of mid-infrared quantum cascade lasers and develop its theoretical description. Its key element is the use of an external ring cavity, which circumvents fundamental issues undermining the stability of mode locking in quantum cascade lasers. We show that active mode locking can give rise to the generation of picosecond pulses and phase-locked frequency combs containing thousands of the ring cavity modes

  7. Can Serum Neutrophil-to-Lymphocyte Ratio Be a Predictive Biomarker to Help Differentiate Active Chronic Otitis Media From Inactive Chronic Otitis Media?

    Science.gov (United States)

    Tansuker, Hasan Deniz; Eroğlu, Sinan; Yenigün, Alper; Taşkin, Ümit; Oktay, Mehmet Faruk

    2017-05-01

    The authors' aim was to investigate whether serum neutrophil to lymphocyte ratio might be used as a predictive biomarker to help differentiate active from inactive chronic otitis media (COM). Two hundred fifty-nine patients having inactive COM received tympanoplasty without mastoidectomy and were identified as Group 1. On the other hand, 254 patients having active COM received tympanoplasty with mastoidectomy and were identified as Group 2. Routine hemogram tests were performed preoperatively for both the groups. By performing a chart review, white blood cell count, red blood cell count, hemoglobin, hematocrit, platelet, and mean platelet volume values were compared between the groups in an age-matched and sex-matched manner. A total of 513 COM patients with age range of 7 to 65 years were included in the study. Two hundred seventy-five patients (53.6%) were male, 238 were (46.4%) female. Preoperatively both serum neutrophil and lymphocyte counts were significantly higher in Group 2 (P = 0.015 and P = 0.004, respectively). However, the neutrophil-to-lymphocyte ratios between the groups were not significantly different (P = 0.511). No statistically significant differences were identified from preoperative neutrophil-to-lymphocyte ratios between patients having active COM and inactive COM. Level NA.

  8. Hollow raspberry-like PdAg alloy nanospheres: High electrocatalytic activity for ethanol oxidation in alkaline media

    Science.gov (United States)

    Peng, Cheng; Hu, Yongli; Liu, Mingrui; Zheng, Yixiong

    2015-03-01

    Palladium-silver (PdAg) alloy nanospheres with unique structure were prepared using a one-pot procedure based on the galvanic replacement reaction. Their electrocatalytic activity for ethanol oxidation in alkaline media was evaluated. The morphology and crystal structure of the samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Electrochemical characterization techniques, including cyclic voltammetry (CV) and chronoamperometry (CA) measurements were used to analyze the electrochemical performance of the PdAg alloy nanospheres. The SEM and TEM images showed that the PdAg alloy nanospheres exhibit a hierarchical nanostructure with hollow interiors and porous walls. Compared to the commercial Pd/C catalyst, the as-prepared PdAg alloy nanospheres exhibit superior electrocatalytic activity and stability towards ethanol electro-oxidation in alkaline media, showing its potential as a new non-Pt electro-catalyst for direct alcohol fuel cells (DAFCs).

  9. Ring-shaped active mode-locked tunable laser using quantum-dot semiconductor optical amplifier

    Science.gov (United States)

    Zhang, Mingxiao; Wang, Yongjun; Liu, Xinyu

    2018-03-01

    In this paper, a lot of simulations has been done for ring-shaped active mode-locked lasers with quantum-dot semiconductor optical amplifier (QD-SOA). Based on the simulation model of QD-SOA, we discussed about the influence towards mode-locked waveform frequency and pulse caused by QD-SOA maximum mode peak gain, active layer loss coefficient, bias current, incident light pulse, fiber nonlinear coefficient. In the meantime, we also take the tunable performance of the laser into consideration. Results showed QD-SOA a better performance than original semiconductor optical amplifier (SOA) in recovery time, line width, and nonlinear coefficients, which makes it possible to output a locked-mode impulse that has a higher impulse power, narrower impulse width as well as the phase is more easily controlled. After a lot of simulations, this laser can realize a 20GHz better locked-mode output pulse after 200 loops, where the power is above 17.5mW, impulse width is less than 2.7ps, moreover, the tunable wavelength range is between 1540nm-1580nm.

  10. Investigation of optical limiting properties of Aluminium nanoparticles prepared by pulsed laser ablation in different carrier media

    International Nuclear Information System (INIS)

    Kuladeep, Rajamudili; Jyothi, L.; Narayana Rao, D.; Prakash, P.; Mayank Shekhar, S.; Durga Prasad, M.

    2013-01-01

    In this communication, we carried out the systematic investigation of nonlinear absorption and scattering properties of Aluminium nanoparticles (Al NPs) in various polar and non-polar solvents. Al NPs were synthesized with pulsed Nd:YAG laser operated at 1064 nm by ablating Al target in polar and non-polar liquid environment like chloroform, chlorobenzene, toluene, benzene, and carbon tetrachloride. Synthesized Al NPs colloids of various solvents differ in appearance and UV-Vis extinction spectra exhibit absorption in the UV region. The characterization of Al NPs performed by Transmission electron microscopy (TEM) studies reveal that NPs are made up of a well crystallized Al inner part (bright zone) embedded with an amorphous metal Al shell (dark region). Growth, aggregation, and precipitation mechanisms which influence the optical properties and stability of NPs are found to be related to the dipole moment of the surrounding liquid environment. The nonlinear absorption and scattering studies are performed by open aperture Z-scan technique with 532 nm under nanosecond pulse excitation. The Z-scan measurements are fitted theoretically to estimate both two-photon absorption (TPA) and nonlinear scattering (NLS) coefficients. In polar solvents like chlorobenzene, chloroform synthesized Al NPs exhibited higher TPA, NLS coefficient values, and lower optical limiting threshold values in comparison with partially polar solvent like toluene and non-polar solvents like benzene and carbontetrachloride. These results indicate the potential use of Al NPs as a versatile optical limiting material

  11. 3D Imaging of Porous Media Using Laser Scanning Confocal Microscopy with Application to Microscale Transport Processes

    Energy Technology Data Exchange (ETDEWEB)

    Fredrich, J.T.

    1999-02-10

    We present advances in the application of laser scanning confocal microscopy (LSCM) to image, reconstruct, and characterize statistically the microgeometry of porous geologic and engineering materials. We discuss technical and practical aspects of this imaging technique, including both its advantages and limitations. Confocal imaging can be used to optically section a material, with sub-micron resolution possible in the lateral and axial planes. The resultant volumetric image data, consisting of fluorescence intensities for typically {approximately}50 million voxels in XYZ space, can be used to reconstruct the three-dimensional structure of the two-phase medium. We present several examples of this application, including studying pore geometry in sandstone, characterizing brittle failure processes in low-porosity rock deformed under triaxial loading conditions in the laboratory, and analyzing the microstructure of porous ceramic insulations. We then describe approaches to extract statistical microgeometric descriptions from volumetric image data, and present results derived from confocal volumetric data sets. Finally, we develop the use of confocal image data to automatically generate a three-dimensional mesh for numerical pore-scale flow simulations.

  12. Using a laser-based CO2 carbon isotope analyser to investigate gas transfer in geological media

    International Nuclear Information System (INIS)

    Guillon, S.; Pili, E.; Agrinier, P.

    2012-01-01

    CO 2 stable carbon isotopes are very attractive in environmental research to investigate both natural and anthropogenic carbon sources. Laser-based CO 2 carbon isotope analysis provides continuous measurement at high temporal resolution and is a promising alternative to isotope ratio mass spectrometry (IRMS). We performed a thorough assessment of a commercially available CO 2 Carbon Isotope Analyser (CCIA DLT-100, Los Gatos Research) that allows in situ measurement of C-13 in CO 2 . Using a set of reference gases of known CO 2 concentration and carbon isotopic composition, we evaluated the precision, long-term stability, temperature sensitivity and concentration dependence of the analyser. Despite good precision calculated from Allan variance (5.0 ppm for CO 2 concentration, and 0.05 per thousand for δC-13 at 60 s averaging), real performances are altered by two main sources of error: temperature sensitivity and dependence of C-13 on CO 2 concentration. Data processing is required to correct for these errors. Following application of these corrections, we achieve an accuracy of 8.7 ppm for CO 2 concentration and 1.3 per thousand for δC-13, which is worse compared to mass spectrometry performance, but still allowing field applications. With this portable analyser we measured CO 2 flux degassed from rock in an underground tunnel. The obtained carbon isotopic composition agrees with IRMS measurement, and can be used to identify the carbon source. (authors)

  13. Opto-acoustic measurement of the local light absorption coefficient in turbid media: 1. Monte-Carlo simulation of laser fluence distribution at the beam axis beneath the surface of a turbid medium

    International Nuclear Information System (INIS)

    Pelivanov, Ivan M; Barskaya, M I; Podymova, N B; Khokhlova, Tanya D; Karabutov, Aleksander A

    2009-01-01

    A new method for measuring the local light absorption coefficient in turbid media, for example, biological tissues, is proposed. The method is based on the fact that the amplitude of the excited opto-acoustic (OA) signal is proportional to the absorbed laser power density (the product of the light absorption coefficient and the laser fluence) at the medium interface. In the first part of the paper, the influence of the laser beam diameter, the light absorption and reduced scattering coefficients on the maximal amplitude of the laser fluence at the laser beam axis in the near-surface layer of the turbid medium is studied by using the Monte-Carlo simulation. The conditions are predicted under which the amplitude of the OA signal detected in a transparent medium in contact with the scattering medium should remain proportional to the light absorption coefficient of the medium under study, when the scattering coefficient in it changes more than twice. The results of the numerical simulation are used for the theoretical substantiation of the OA method being proposed. (measurement of parametrs of laser radiation)

  14. Optimizing the active region of interband cascade lasers for passive mode-locking

    Directory of Open Access Journals (Sweden)

    K. Ryczko

    2017-01-01

    Full Text Available The work proposes possible designs of active regions for a mode-locked interband cascade laser emitting in the mid infrared. For that purpose we investigated the electronic structure properties of respectively modified GaSb-based type II W-shaped quantum wells, including the effect of external bias in order to simultaneously fulfil the requirements for both the absorber as well as the gain sections of a device. The results show that introducing multiple InAs layers in type II InAs/GaInSb quantum wells or introducing a tensely-strained GaAsSb layer into “W-shaped” type II QWs offers significant difference in optical transitions’ oscillator strengths (characteristic lifetimes of the two oppositely polarized parts of such a laser, being promising for utilization in mode-locked devices.

  15. Laser activation of Ultra Shallow Junctions (USJ) doped by Plasma Immersion Ion Implantation (PIII)

    International Nuclear Information System (INIS)

    Vervisch, Vanessa; Larmande, Yannick; Delaporte, Philippe; Sarnet, Thierry; Sentis, Marc; Etienne, Hasnaa; Torregrosa, Frank; Cristiano, Fuccio; Fazzini, Pier Francesco

    2009-01-01

    Today, the main challenges for the realization of the source/drain extensions concern the ultra-low energy implantation and the activation of the maximum amount of dopants with a minimized diffusion. Among the different annealing processes, one solution is the laser thermal annealing. Many studies [F. Torregrosa, C. Laviron, F. Milesi, M. Hernandez, H. Faik, J. Venturini, Proc. 14th International Conference on Ion Implant Technology, 2004; M. Hernandez, J. Venturini, D. Zahorski, J. Boulmer, D. Debarre, G. Kerrien, T. Sarnet, C. Laviron, M.N Semeria, D. Camel, J.L Santailler, Appl. Surf. Sci. 208-209 (2003) 345-351] have shown that the association of Plasma Immersion Ion Implantation (PIII) and Laser Thermal Process (LTP) allows to obtain junctions of a few nanometers with a high electrical activation. All the wafers studied have been implanted by PULSION (PIII implanter developed by Ion Beam Services) with an acceleration voltage of 1 kV and a dose of 6 x 10 15 at./cm 2 . In this paper, we compare the annealing process achieved with three excimer lasers: ArF, KrF and XeCl with a wavelength of respectively 193, 248 and 308 nm. We analyse the results in terms of boron activation and junction depth. To complete this study, we have observed the effect of pre-amorphization implantation (PAI) before PIII process on boron implantation and boron activation. We show that Ge PAI implanted by classical beam line allows a decrease of the junction depth from 20 down to 12 nm in the as-implanted condition. Transmission Electron Microscopy (TEM) analyses were performed in order to study the structure of pre-amorphized silicon and to estimate the thickness of the amorphous layer. In order to determine the sheet resistance (R s ) and the junction depth (X j ), we have used the four-point probe technique (4PP) and secondary ion mass spectrometry (SIMS) analysis. To complete the electrical characterizations some samples have been analyzed by non-contact optical measurements. All the

  16. EFNEP graduates' perspectives on social media to supplement nutrition education: focus group findings from active users.

    Science.gov (United States)

    Leak, Tashara M; Benavente, Lisa; Goodell, L Suzanne; Lassiter, Annie; Jones, Lorelei; Bowen, Sarah

    2014-01-01

    To identify ways to effectively use social media to communicate nutrition-related information to low-income populations. The authors conducted 4 focus groups with female Expanded Food and Nutrition Education Program graduates who used social media at least twice a week (n = 26 total). Transcripts were analyzed using the constant comparative method to identify key themes. For participants, page content, page maintenance, and networking opportunities with others were important aspects of a nutrition education social media page. Trust emerged as a central theme, because participants expressed a need for reliable information from known, credible sources and safe places to share ideas. Using social media to provide nutrition-related messages may be an effective way to encourage sustained positive behavior changes resulting from educational programming and to engage participants beyond class time. Establishing the trustworthiness of the social media site is essential to its use among low-income participants. Copyright © 2014 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  17. High-power Al-free active region (λ= 852nm) DFB laser diodes for atomic clocks and interferometry applications

    Science.gov (United States)

    Ligeret, V.; Vermersch, F.-J.; Bansropun, S.; Lecomte, M.; Calligaro, M.; Parillaud, O.; Krakowski, M.

    2017-11-01

    Atomic clocks will be used in the future European positioning system Galileo. Among them, the optically pumped clocks provide a better alternative with comparable accuracy for a more compact system. For these systems, diode lasers emitting at 852nm are strategic components. The laser in a conventional bench for atomic clocks presents disadvantages for spatial applications. A better approach would be to realise a system based on a distributed-feedback laser (DFB). We have developed the technological foundations of such lasers operating at 852nm. These include an Al free active region, a single spatial mode ridge waveguide and a DFB structure. The device is a separate confinement heterostructure with a GaInP large optical cavity and a single compressive strained GaInAsP quantum well. The broad area laser diodes are characterised by low internal losses (value of less than 2MHz.

  18. Second space Christmas for ESA: Huygens to begin its final journey to Titan/ Media activities.

    Science.gov (United States)

    2004-12-01

    , designed, developed and assembled the Cassini orbiter. NASA's Deep Space Network, also managed by JPL, will be providing communications support via the Cassini orbiter and relaying it to ESA’s control centre in Darmstadt for processing. The Italian Space Agency provided the high-gain antenna on the Cassini orbiter, much of the radio system and elements of several of Cassini's science instruments. The Huygens payload has been provided by teams including from CNES, DLR, ASI and PPARC, and outside Europe, from NASA. Practical arrangements for the Media wishing to cover the event These dramatic events marking the first attempt ever to unveil the mysteries of Titan in-situ, a distant world bigger than Mercury and Pluto which may hold clues to the early days of our own planet, will be marked by several media activities not to be missed. Pencil them into your diary. Saturday 25 December Spacecraft operations will be run at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. The ESA Media Relations Office in Paris will be operational from 04:00 hrs to 12:00 CET. ESA specialists can be reached for interviews and comments via the ESA News Desk on +33(0)1.53.69.71.55. Contacts: Franco Bonacina, Anne-Marie Rémondin, Roberto Lo Verde. Interviews from JPL can also be arranged by calling the JPL media relations office at + 1. 818-354-5011. ESA specialists at JPL: Jean-Pierre Lebreton, Claudio Sollazzo. 05:08 CET - Expected separation of the Huygens probe from the Cassini orbiter ~07:00 CET - Status report upon successful separation from NASA/JPL 10:00 CET at the latest : ESA press release assessing the separation of the Huygens probe ~10:00 CET - ESA TV Video News Release produced at JPL during separation (contact for TVs: Claus Habfast: + 31(0)6.51.18.14.96, claus.habfast@esa.int) Transmission details will be on http://television.esa.int 12:00 CET - Replay of ESA TV Video News Release on separation Thursday 13 January ESA’s ESOC establishment in Darmstadt, Germany

  19. Penetration of 35% hydrogen peroxide into the pulp chamber in bovine teeth after LED or Nd:YAG laser activation.

    Science.gov (United States)

    Camargo, Samira Esteves Afonso; Cardoso, Paula Elaine; Valera, Marcia Carneiro; de Araújo, Maria Amélia Máximo; Kojima, Alberto Noriyuki

    2009-01-01

    This aim of the present study was to evaluate the pulp chamber penetration of 35% hydrogen peroxide activated by LED (light-emitting diode) or Nd:YAG laser in bovine teeth, after an in-office bleaching technique. Forty-eight bovine lateral incisors were divided into four groups, acetate buffer was placed into the pulp chamber and bleaching agent was applied as follows: for group A (n = 12), activation was performed by LED; for group B (n = 12), activation was performed by Nd:YAG laser (60 mJ, 20 Hz); group C (n = 12) received no light or laser activation; and the control group (n = 12) received no bleaching gel application or light or laser activation. The acetate buffer solution was transferred to a glass tube and Leuco Crystal Violet and horseradish peroxidase were added, producing a blue solution. The optical density of this solution was determined spectrophotometrically and converted into microgram equivalents of hydrogen peroxide. The results were analysed using ANOVA and Tukey's test (5%). It was verified that the effect of activation was significant, as groups activated by LED or laser presented greater hydrogen peroxide penetration into the pulp chamber (0.499 +/- 0.622 microg) compared with groups that were not (0.198 +/- 0.218 microg). There was no statistically significant difference in the penetration of hydrogen peroxide into the pulp chamber between the two types of activation (LED or laser). The results suggest that activation by laser or LED caused an increase in hydrogen peroxide penetration into the pulp chamber.

  20. Pulsed inductive HF laser

    Energy Technology Data Exchange (ETDEWEB)

    Razhev, A M; Kargapol' tsev, E S [Institute of Laser Physics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation); Churkin, D S; Demchuk, S V [Novosibirsk State University, Novosibirsk (Russian Federation)

    2016-03-31

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H{sub 2} – F{sub 2}(NF{sub 3} or SF6{sub 6}) and He(Ne) – H{sub 2} – F{sub 2}(NF{sub 3} or SF{sub 6}) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% – 6%. (lasers)

  1. EFFECTS OF COOPERATIVE LEARNING MODEL TYPE NUMBERED HEADS TOGETHER USING SIMULATION MEDIA PHET AND ACTIVITIES TOWARD STUDENT RESULTS

    Directory of Open Access Journals (Sweden)

    Fitri Mawaddah Lubis

    2015-12-01

    Full Text Available This study aimed to analyze the differences in learning outcomes of students taught by cooperative learning model NHT using simulation PhET and conventional learning, analyzing the differences in learning outcomes of students who have high activity and low activity, as well as the  interaction between learning model with the level of student activity in  influencing the outcome students learn physics. This research is a quasi experimental. The population in this study were students of class X SMK Tritech Informatika Medan. The tests were used to obtain the data is in the form of multiple choice. Test requirements have been carried out in the form of normality and homogeneity, which showed that the normal data and homogeneous. The data were analyzed using Anova analysis of two paths. The results showed that: The physics learning outcomes of students who use cooperative learning model NHT using PhET simulations media is better than students who use conventional learning models. The physics learning outcomes of students who have high learning activities is better than students who have Low learning activities. There is an interaction between cooperative learning model NHT PhET simulations using the media and the level of learning activity in influencing student learning outcomes. Average increase learning outcomes in the control class is greater than the experimental class.

  2. Active retroreflector to measure the rotational orientation in conjunction with a laser tracker

    Science.gov (United States)

    Hofherr, O.; Wachten, C.; Müller, C.; Reinecke, H.

    2012-10-01

    High precision optical non-contact position measurement is a key technology in modern engineering. Laser trackers (LT) can determine accurately x-y-z coordinates of passive retroreflectors. Next-generation systems answer the additional need to measure an object's rotational orientation (pitch, yaw, roll). These devices are based on photogrammetry or on enhanced retroreflectors. However, photogrammetry relies on camera systems and time-consuming image processing. Enhanced retroreflectors analyze the LT's beam but are restricted in roll angle measurements. Here we present an integrated laser based method to evaluate all six degrees of freedom. An active retroreflector directly analyzes its orientation to the LT's beam path by outcoupling laser light on detectors. A proof of concept prototype has been designed with a specified measuring range of 360° for roll angle measurements and +/-15° for pitch and yaw angle respectively. The prototype's optical design is inspired by a cat's eye retroreflector. First results are promising and further improvements are under development. We anticipate our method to facilitate simple and cost-effective six degrees of freedom measurements. Furthermore, for industrial applications wide customizations are possible, e.g. adaptation of measuring range, optimization of accuracy, and further system miniaturization.

  3. Recovery of homogeneous polyoxometallate catalysts from aqueous and organic media by a mesoporous ceramic membrane without loss of catalytic activity.

    Science.gov (United States)

    Roy Chowdhury, Sankhanilay; Witte, Peter T; Blank, Dave H A; Alsters, Paul L; Ten Elshof, Johan E

    2006-04-03

    The recovery of homogeneous polyoxometallate (POM) oxidation catalysts from aqueous and non-aqueous media by a nanofiltration process using mesoporous gamma-alumina membranes is reported. The recovery of Q(12)[WZn(3)(ZnW(9)O(34))(2)] (Q=[MeN(n-C(8)H(17))(3)](+)) from toluene-based media was quantitative within experimental error, while up to 97 % of Na(12)[WZn(3)(ZnW(9)O(34))(2)] could be recovered from water. The toluene-soluble POM catalyst was used repeatedly in the conversion of cyclooctene to cyclooctene oxide and separated from the product mixture after each reaction. The catalytic activity increased steadily with the number of times that the catalyst had been recycled, which was attributed to partial removal of the excess QCl that is known to have a negative influence on the catalytic activity. Differences in the permeability of the membrane for different liquid media can be attributed to viscosity differences and/or capillary condensation effects. The influence of membrane pore radius on permeability and recovery is discussed.

  4. Is there a relationship between myeloperoxidase activity and conductive hearing loss in chronic otitis media complicated by cholesteatoma?

    Science.gov (United States)

    Celebi Erdivanli, Ozlem; Sanli, Arif

    2015-01-01

    We conducted a prospective, controlled study of patients with chronic otitis media and cholesteatoma (1) to examine the expression of myeloperoxidase (MPO) using immunohistochemical staining techniques and (2) to investigate the relationship between MPO activity and the degree of conductive hearing loss in these patients. Our study population included 51 adults-26 men and 25 women, aged 18 to 58 years (mean: 37.5)-who had been diagnosed with chronic otitis media and cholesteatoma by physical examination and computed tomography (study group). Another 30 patients-13 men and 17 women, aged 18 to 52 years (mean: 32.7)-who had chronic otitis media without cholesteatoma served as the control group. Following audiometric evaluations, all patients underwent appropriate surgery. Postoperatively, cholesteatoma samples were analyzed by immunostaining for MPO positivity as a marker for acute inflammation. We found that MPO activity was present in all 51 study patients (100%) but in only 10 controls (33.3%); the difference was statistically significant (pconductive hearing loss (χ(2) = 13.518; p < 0.001). We encourage further study of all steps in the process of cholesteatoma formation.

  5. The effect of owned and earned social media activities towards purchase intention on Facebook

    Directory of Open Access Journals (Sweden)

    Alriz Tsabit Rusdan

    2018-06-01

    Full Text Available With the growth of internet connection, the Indonesia people are getting more and more connected to each other with the rise of social media, especially facebook in which nowadays has become one of the mainstream channel for companies to inform their product and to share their brand value to the consumer. This research will oversee the technology acceptance aspect in which affected by the ease of use and joyfulness of the users, owned social media aspect or the channel that are owned and can be controlled by companies or brand alike whose the acceptance of the information are affected by usefulness, reputation, trust, and altruism. And the earned social media aspects which are affected by information acceptance and social connection. The research are conducted by sending questioners to facebook users who is a consumer of Stella air freshener products. The research shown that technology acceptance aspects are not significantly affected the perception of a product fanpage, in the contrary earned and owned social media aspects along with the factors that affecting it has shown as significantly affected the perception of the users in facebook toward the fanpage, who in the end will affecting their purchase intention to the product of the fanpage.

  6. Millennials, Technology and Perceived Relevance of Community Service Organizations: Is Social Media Replacing Community Service Activities?

    Science.gov (United States)

    Hoffman, August John

    2017-01-01

    This mixed-methods qualitative study examined the relationship between perceptions of the importance of social media (i.e., Facebook, Twitter) with community service projects and volunteerism. Participants (n = 80) were interviewed and surveyed regarding their experiences in participating in a variety of community service work (CSW) projects…

  7. Using Social Media Activity to Identify Personality Characteristics of Navy Personnel

    Science.gov (United States)

    2016-03-01

    1]. The list of social media platforms is constantly growing. The most commonly used platforms are YouTube , Facebook, Google+, and Twitter; others...such as anxiety, anger, depression , self- consciousness, impulsiveness, and vulnerability • Openness to Experience, described with terms such as fantasy

  8. Contested Science in the Media: Linguistic Traces of News Writers' Framing Activity

    Science.gov (United States)

    Dahl, Trine

    2015-01-01

    Science reporting in the media often involves contested issues, such as, for example, biotechnology, climate change, and, more recently, geoengineering. The reporter's framing of the issue is likely to influence readers' perception of it. The notion of framing is related to how individuals and groups perceive and communicate about the…

  9. Table of laser lines in gases and vapors

    Energy Technology Data Exchange (ETDEWEB)

    Beck, R; Englisch, W; Guers, K

    1980-01-01

    Numerous applications of lasers require use of specific wavelengths (gas analysis including remote sensing, Raman spectroscopy, optical pumping, laser chemistry and isotope separation). Scientists active in these fields have been compelled to search, in addition to the available, mostly obsolete, laser-line tables, the entire recent literature in order to find suitable laser transitions. Over 6100 laser transitions are presented. An additional list of the lines arranged in order of wavelength should greatly facilitate the search for a laser material that generates a specific wavelength. Further information has also been supplied by listing the pump transition for each of the FIR lines obtained with the optically pumped organic vapors. In addition to the laser lines, the operating conditions under which emission has been achieved are briefly specified at the top of the list for each active medium. The order in which the atomic laser media are listed is based on the periodic system, beginning with the noble gases, continuing with hydrogen and the alkalies to the halogens and the rare earths. The molecular laser media are arranged in order of chemical composition, beginning with the compounds of noble gases (the excimers), then other diatomic molecules, triatomic molecules, and ending with the more complex molecules of organic vapors. (WHK).

  10. Antimicrobial effect of pleomeleangustifolia pheophytin A activation with diode laser to streptococcus mutans

    Science.gov (United States)

    Alfat Sunarko, Sinari; Ekasari, Wiwied; Dyah Astuti, Suryani

    2017-05-01

    The main purpose of this research is to identify potential of Pheophytin A. as photosensitizer a agent to inactivate Streptococcus muttans using laser diode of 405nm. Pheophytina is known as chlorophyll derivate that losses magnesium ion at the center of porphyrin ring structure. In this research, phrophytin was extracted from Suji leaf (Pleomeleangustifolia). To determine the antimicrobial effect of treatments on S. mutans, samples were divided into three groups as follows: (1) Groups A(treated with Pheophytin A. and laser 405 nm at varying energy density of 2.5; 5, 7.5; 10.0; 12.5; 15.0; 17.5 and 20.0 J/cm2), (2) Group C-(negative control, no treated), (3) Group C+ (treated only with pheophytin). The experiments were repeated at least three times for each group. The results were analyzed using analysis of variance and the Tukey test. A P value ≤0.05 was considered to indicate a statistically significant difference. The decrement of percentage of number of bacterial colonyes growth was defined as: | (Σ sample colony - Σ control colony)/ Σ control colony | x 100%. The result showed that the incubation of Pheophytin A. using irradiation from laser diode of 405nm have a significant effect towards the decrement in bacterial growth. The most decreased percentage colony of S. mutans occurred on the incubation of pheophytin a treatment and laser irradiation 405nm with density 20 J/cm2 is 61.9%. This showed that pheophytin a functions as a photosesitizer activator to inactivate S. mutans bacteria.

  11. Antimicrobial effect of pleomeleangustifolia pheophytin A activation with diode laser to streptococcus mutans

    International Nuclear Information System (INIS)

    Sunarko, Sinari Alfat; Astuti, Suryani Dyah; Ekasari, Wiwied

    2017-01-01

    The main purpose of this research is to identify potential of Pheophytin A. as photosensitizer a agent to inactivate Streptococcus muttans using laser diode of 405nm. Pheophytina is known as chlorophyll derivate that losses magnesium ion at the center of porphyrin ring structure. In this research, phrophytin was extracted from Suji leaf (Pleomeleangustifolia). To determine the antimicrobial effect of treatments on S. mutans , samples were divided into three groups as follows: (1) Groups A(treated with Pheophytin A. and laser 405 nm at varying energy density of 2.5; 5, 7.5; 10.0; 12.5; 15.0; 17.5 and 20.0 J/cm 2 ), (2) Group C - (negative control, no treated), (3) Group C + (treated only with pheophytin). The experiments were repeated at least three times for each group. The results were analyzed using analysis of variance and the Tukey test. A P value ≤0.05 was considered to indicate a statistically significant difference. The decrement of percentage of number of bacterial colonyes growth was defined as: | (Σ sample colony - Σ control colony)/ Σ control colony | x 100%. The result showed that the incubation of Pheophytin A. using irradiation from laser diode of 405nm have a significant effect towards the decrement in bacterial growth. The most decreased percentage colony of S. mutans occurred on the incubation of pheophytin a treatment and laser irradiation 405nm with density 20 J/cm 2 is 61.9%. This showed that pheophytin a functions as a photosesitizer activator to inactivate S. mutans bacteria. (paper)

  12. Final Report - Montana State University - Microbial Activity and Precipitation at Solution-Solution Mixing Zones in Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Gerlach, Robin [Montana State University

    2014-10-31

    Background. The use of biological and chemical processes that degrade or immobilize contaminants in subsurface environments is a cornerstone of remediation technology. The enhancement of biological and chemical processes in situ, involves the transport, displacement, distribution and mixing of one or more reactive agents. Biological and chemical reactions all require diffusive transport of solutes to reaction sites at the molecular scale and accordingly, the success of processes at the meter-scale and larger is dictated by the success of phenomena that occur at the micron-scale. However, current understanding of scaling effects on the mixing and delivery of nutrients in biogeochemically dynamic porous media systems is limited, despite the limitations this imposes on the efficiency and effectiveness of the remediation challenges at hand. Objectives. We therefore proposed to experimentally characterize and computationally describe the growth, evolution, and distribution of microbial activity and mineral formation as well as changes in transport processes in porous media that receive two or more reactive amendments. The model system chosen for this project was based on a method for immobilizing 90Sr, which involves stimulating microbial urea hydrolysis with ensuing mineral precipitation (CaCO3), and co-precipitation of Sr. Studies at different laboratory scales were used to visualize and quantitatively describe the spatial relationships between amendment transport and consumption that stimulate the production of biomass and mineral phases that subsequently modify the permeability and heterogeneity of porous media. Biomass growth, activity, and mass deposition in mixing zones was investigated using two-dimensional micro-model flow cells as well as flow cells that could be analyzed using synchrotron-based x-ray tomography. Larger-scale flow-cell experiments were conducted where the spatial distribution of media properties, flow, segregation of biological activity and

  13. Passive, active, and hybrid mode-locking in a self-optimized ultrafast diode laser

    Science.gov (United States)

    Alloush, M. Ali; Pilny, Rouven H.; Brenner, Carsten; Klehr, Andreas; Knigge, Andrea; Tränkle, Günther; Hofmann, Martin R.

    2018-02-01

    Semiconductor lasers are promising sources for generating ultrashort pulses. They are directly electrically pumped, allow for a compact design, and therefore they are cost-effective alternatives to established solid-state systems. Additionally, their emission wavelength depends on the bandgap which can be tuned by changing the semiconductor materials. Theoretically, the obtained pulse width can be few tens of femtoseconds. However, the generated pulses are typically in the range of several hundred femtoseconds only. Recently, it was shown that by implementing a spatial light modulator (SLM) for phase and amplitude control inside the resonator the optical bandwidth can be optimized. Consequently, by using an external pulse compressor shorter pulses can be obtained. We present a Fourier-Transform-External-Cavity setup which utilizes an ultrafast edge-emitting diode laser. The used InGaAsP diode is 1 mm long and emits at a center wavelength of 850 nm. We investigate the best conditions for passive, active and hybrid mode-locking operation using the method of self-adaptive pulse shaping. For passive mode-locking, the bandwidth is increased from 2.34 nm to 7.2 nm and ultrashort pulses with a pulse width of 216 fs are achieved after external pulse compression. For active and hybrid mode-locking, we also increased the bandwidth. It is increased from 0.26 nm to 5.06 nm for active mode-locking and from 3.21 nm to 8.7 nm for hybrid mode-locking. As the pulse width is strongly correlated with the bandwidth of the laser, we expect further reduction in the pulse duration by increasing the bandwidth.

  14. Simultaneous fabrication of laser-active colour centres and permanent microgratings in lithium fluoride by a single femtosecond pulse

    International Nuclear Information System (INIS)

    Kurobori, Toshio; Kawamura, Ken-ichi; Hirano, Masahiro; Hosono, Hideo

    2003-01-01

    We report, for the first time, simultaneous fabrication of laser-active F 2 and F 3 + colour centres in lithium fluoride and permanent periodic gratings with fringe spacings as fine as sub-micron size by two interfering infrared femtosecond (fs) laser pulses. In particular, the optical properties (absorption and luminescence) of F 2 and F 3 + colour centres produced by a single fs laser pulse are compared with those created by damage from radiation such as x-rays. The present technique of simultaneously fabricating laser-active colour centres and functional fine-periodic structures in photo-insensitive transparent materials may well be a useful method for making miniaturized optical devices. (letter to the editor)

  15. Dispersive-cavity actively mode-locked fiber laser for stable radio frequency delivery

    International Nuclear Information System (INIS)

    Dai, Yitang; Wang, Ruixin; Yin, Feifei; Xu, Kun; Li, Jianqiang; Lin, Jintong

    2013-01-01

    We report a novel technique for highly stable transfer of a radio frequency (RF) comb over long optical fiber link, which is highly dispersive and is a part of an actively mode-locked fiber laser. Phase fluctuation along the fiber link, which is mainly induced by physical vibration and temperature fluctuations, is automatically compensated by the self-adapted wavelength shifting. Without phase-locking loop or any tunable parts, stable radio frequency is transferred over a 2-km fiber link, with a time jitter suppression ratio larger than 110. (letter)

  16. Social media management and media environment

    Directory of Open Access Journals (Sweden)

    Šiđanin Iva

    2012-01-01

    Full Text Available The paper deals with the system of services that social media management can offer to a variety of users. As social media systems are emerging, social media management can strengthen teams in social media and help to manage numerous social channels and distribution of social information from one place. Social media management is a system of procedures that are used to manage the flow of information in the environment of social media. This involves connecting with social media like Facebook, Twitter, LinkedIn, Plaxo, Ecademy, YouTube and many others, then the aggregation and management of social data. Social media management services are analysed through various fields, such as managing multiple social media profiles, mail scheduling and filtering, reporting and analytics. Social media management enables managing personal business through social media, which contributes to a significant reduction in expenditures. The paper also discusses the importance of social media management in marketing activities and various forms of social promotion, which allow companies to easily reach their customers.

  17. Lasers in ophthalmology: achievements and new directions

    Science.gov (United States)

    Carstocea, Benone D.; Apostol, Silvia; Gafencu, Otilia L.

    1995-03-01

    The main characteristics of the laser radiations are: directivity, monochromaticity and spatially and temporally coherence. Using the aggregation state as a criterion for classification, we describe solid, liquid and gaseous active media. Concerning the methods used to realize the population inversion, we also describe: optically, electrically and high energy particles pumped lasers. Depending on the laser media and the mode of excitation, a laser may operate in multiple ways: the continuous-wave operation, the long-pulsed operation, the Q-switched mode of operation and the mode-locked operation. The interaction of laser radiations with the living matter is based upon four main effects: the thermal, mechanical, electrical and biological effect. The main field of therapeutical use of lasers are: the management of lid tumors and intraocular tumors, dacryocystorhinostomy, the treatment of diabetic retinopathy, thromboembolic retinal syndromes, inflammatory choriretinal disease, chorioroetinal degenerations, retinal angimatosis, retinal breaks and retinal detachment, corneal diseases, glaucoma, lens diseases. Laser has also nontherapeutical applications in diagnosis and prognosis of ophthalmologic diseases.

  18. Measurement of laser welding pool geometry using a closed convex active contour model

    International Nuclear Information System (INIS)

    Zheng, Rui; Zhang, Pu; Duan, Aiqing; Xiao, Peng

    2014-01-01

    The purpose of this study was to develop a computer vision method to measure geometric parameters of the weld pool in a deep penetration CO 2 laser welding system. Accurate measurement was achieved by removing a huge amount of interference caused by spatter, arc light and plasma to extract the true weld pool contour. This paper introduces a closed convex active contour (CCAC) model derived from the active contour model (snake model), which is a more robust high-level vision method than the traditional low-level vision methods. We made an improvement by integrating an active contour with the information that the weld pool contour is almost a closed convex curve. An effective thresholding method and an improved greedy algorithm are also given to complement the CCAC model. These influences can be effectively removed by using the CCAC model to acquire and measure the weld pool contour accurately and relatively fast. (paper)

  19. Oxygen reduction activity of N-doped carbon-based films prepared by pulsed laser deposition

    Science.gov (United States)

    Hakoda, Teruyuki; Yamamoto, Shunya; Kawaguchi, Kazuhiro; Yamaki, Tetsuya; Kobayashi, Tomohiro; Yoshikawa, Masahito

    2010-12-01

    Carbon-based films with nitrogen species on their surface were prepared on a glassy carbon (GC) substrate for application as a non-platinum cathode catalyst for polymer electrolyte fuel cells. Cobalt and carbon were deposited in the presence of N 2 gas using a pulsed laser deposition method and then the metal Co was removed by HCl-washing treatment. Oxygen reduction reaction (ORR) activity was electrochemically determined using a rotating disk electrode system in which the film samples on the GC substrate were replaceable. The ORR activity increased with the temperature of the GC substrate during deposition. A carbon-based film prepared at 600 °C in the presence of N 2 at 66.7 Pa showed the highest ORR activity among the tested samples (0.66 V vs. NHE). This film was composed of amorphous carbons doped with pyridine type nitrogen atoms on its surface.

  20. Effect of Sample Preparation on the Discrimination of Bacterial Isolates Cultured in Liquid Nutrient Media Using Laser-Induced Breakdown Spectroscopy (LIBS).

    Science.gov (United States)

    Gamble, Gary R; Park, Bosoon; Yoon, Seung-Chul; Lawrence, Kurt C

    2016-03-01

    Laser-induced breakdown spectroscopy (LIBS) is used as the basis for discrimination between two genera of gram-negative bacteria and two genera of gram-positive bacteria representing pathogenic threats commonly found in poultry processing rinse waters. Because LIBS-based discrimination relies primarily upon the relative proportions of inorganic cell components including Na, K, Mg, and Ca, this study aims to determine the effects of trace mineral content and pH found in the water source used to isolate the bacteria upon the reliability of the resulting discriminant analysis. All four genera were cultured using tryptic soy agar (TSA) as the nutrient medium, and were grown under identical environmental conditions. The only variable introduced is the source water used to isolate the cultured bacteria. Cultures of each bacterium were produced using deionized (DI) water under two atmosphere conditions, reverse osmosis (RO) water, tap water, phosphate buffered saline (PBS) water, and TRIS buffered water. After 3 days of culture growth, the bacteria were centrifuged and washed three times in the same water source. Bacteria were then freeze dried, mixed with microcrystalline cellulose, and a pellet was made for LIBS analysis. Principal component analysis (PCA) was used to extract related variations in LIBS spectral data among the four bacteria genera and six water types used to isolate the bacteria, and Mahalanobis discriminant analysis (MDA) was used for classification. Results indicate not only that the four genera can be discriminated from each other in each water type, but that each genus can be discriminated by water type used for isolation. It is concluded that in order for LIBS to be a reliable and repeatable method for discrimination of bacteria grown in liquid nutrient media, care must be taken to insure that the water source used in purification of the culture be precisely controlled regarding pH, ionic strength, and proportionate amounts of mineral cations

  1. Direct comparison of Yb3+-doped LiYF4 and LiLuF4 as laser media at room-temperature

    International Nuclear Information System (INIS)

    Yin, J G; Hang, Y; He, X M; Zhang, L H; Zhao, C C; Gong, J; Zhang, P X

    2012-01-01

    We present an extensive comparative analysis on the growth, the spectroscopic features, and the laser performances of room temperature Yb(5%):LiYF 4 (YLF) and Yb(5%):LiLuF 4 (LLF) crystals in the same conditions. The gain cross section, fluorescence lifetimes, laser thresholds and laser slope efficiencies are compared for the first time. It appears that Yb 3+ -doped LLF crystal might be more promising for diode-pumped high power laser operation

  2. Open Source Analysis in Support to Nonproliferation Monitoring and Verification Activities: Using the New Media to Derive Unknown New Information

    International Nuclear Information System (INIS)

    Pabian, F.; Renda, G.; Jungwirth, R.; Kim, L.; Wolfart, E.; Cojazzi, G.G.M.; )

    2015-01-01

    This paper will describe evolving techniques that leverage freely available open source social media venues, sometimes referred to as the ''New Media,'' together with geospatial tools and commercial satellite imagery (with its ever improving spatial, spectral, and temporal resolutions), to expand the existing nuclear non-proliferation knowledge base by way of a review of some recent exemplar cases. The application of such techniques can enhance more general data mining, as those techniques can be more directly tailored to IAEA Safeguards monitoring and other non-proliferation verification activities to improve the possibility of the remote detection of undeclared nuclear related facilities and/or activities. As part of what might be called the new ''Societal Verification'' regime, these techniques have enlisted either the passive or active involvement of interested parties (NGOs, academics, and even hobbyists) using open sources and collaboration networks together with previously highlighted geospatial visualization tools and techniques. This paper will show how new significant, and unprecedented, information discoveries have already been made (and published in open source) in the last four years, i.e., since the last IAEA Safeguards Symposium. With respect to the possibility of soliciting active participation (e.g., ''crowd-sourcing'') via social media, one can envision scenarios (one example from open source will be provided) whereby a previously unknown nuclear related facility could be identified or located through the online posting of reports, line drawings, and/or ground photographs. Nonetheless, these techniques should not be viewed as a panacea, as examples of both deception and human error will also be provided. This paper will highlight the use of these remote-means of discovery techniques, and how they have shed entirely new light on important nuclear non-proliferation relevant issues in

  3. How the news media activate public expression and influence national agendas.

    Science.gov (United States)

    King, Gary; Schneer, Benjamin; White, Ariel

    2017-11-10

    We demonstrate that exposure to the news media causes Americans to take public stands on specific issues, join national policy conversations, and express themselves publicly-all key components of democratic politics-more often than they would otherwise. After recruiting 48 mostly small media outlets, we chose groups of these outlets to write and publish articles on subjects we approved, on dates we randomly assigned. We estimated the causal effect on proximal measures, such as website pageviews and Twitter discussion of the articles' specific subjects, and distal ones, such as national Twitter conversation in broad policy areas. Our intervention increased discussion in each broad policy area by ~62.7% (relative to a day's volume), accounting for 13,166 additional posts over the treatment week, with similar effects across population subgroups. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  4. Removal of arsenic and methylene blue from water by granular activated carbon media impregnated with zirconium dioxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, Robert; Cooper, Anne Marie; Aymar, Kathryn; Jain, Arti [Environmental Technology, College of Technology and Innovation, Arizona State University, 6073 S. Backus Mall, Mesa, AZ 85212 (United States); Hristovski, Kiril, E-mail: Kiril.Hristovski@asu.edu [Environmental Technology, College of Technology and Innovation, Arizona State University, 6073 S. Backus Mall, Mesa, AZ 85212 (United States)

    2011-10-15

    Highlights: {yields} The morphology, content and distribution of ZrO{sub 2} nanoparticles inside the pores of GAC are affected by the type of GAC. {yields} Lignite ZrO{sub 2}-GAC exhibited Zr content of 12%, while bituminous based ZrO{sub 2}-GAC exhibited Zr content of 9.5%. {yields} The max. adsorption capacities under equilibrium conditions in 5 mM NaHCO{sub 3} buffered water matrix were {approx}8.6 As/g Zr and {approx}12.2 mg As/g Zr at pH = 7.6. {yields} The max. adsorption capacities under equilibrium conditions in NSF 53 Challenge water matrix while {approx}1.5 mg As/g Zr and {approx}3.2 mg As/g Zr at pH = 7.6. {yields} Introduction of nanoparticles did not impact the MB adsorption capacity of the lignite ZrO{sub 2}-GAC, while the one of bituminous ZrO{sub 2}-GAC decreased. - Abstract: This study investigated the effects of in situ ZrO{sub 2} nanoparticle formation on properties of granulated activated carbon (GAC) and their impacts on arsenic and organic co-contaminant removal. Bituminous and lignite based zirconium dioxide impregnated GAC (Zr-GAC) media were fabricated by hydrolysis of zirconium salt followed by annealing of the product at 400 {sup o}C in an inert environment. Media characterization suggested that GAC type does not affect the crystalline structure of the resulting ZrO{sub 2} nanoparticles, but does affect zirconium content of the media, nanoparticle morphology, nanoparticle distribution, and surface area of Zr-GAC. The arsenic removal performance of both media was compared using 5 mM NaHCO{sub 3} buffered ultrapure water and model groundwater containing competing ions, both with an initial arsenic C{sub 0} {approx} 120 {mu}g/L. Experimental outcomes suggested favorable adsorption energies and higher or similar adsorption capacities than commercially available or experimental adsorbents when compared on the basis of metal content. Short bed adsorber column tests showed that arsenic adsorption capacity decreases as a result of kinetics of

  5. Removal of arsenic and methylene blue from water by granular activated carbon media impregnated with zirconium dioxide nanoparticles

    International Nuclear Information System (INIS)

    Sandoval, Robert; Cooper, Anne Marie; Aymar, Kathryn; Jain, Arti; Hristovski, Kiril

    2011-01-01

    Highlights: → The morphology, content and distribution of ZrO 2 nanoparticles inside the pores of GAC are affected by the type of GAC. → Lignite ZrO 2 -GAC exhibited Zr content of 12%, while bituminous based ZrO 2 -GAC exhibited Zr content of 9.5%. → The max. adsorption capacities under equilibrium conditions in 5 mM NaHCO 3 buffered water matrix were ∼8.6 As/g Zr and ∼12.2 mg As/g Zr at pH = 7.6. → The max. adsorption capacities under equilibrium conditions in NSF 53 Challenge water matrix while ∼1.5 mg As/g Zr and ∼3.2 mg As/g Zr at pH = 7.6. → Introduction of nanoparticles did not impact the MB adsorption capacity of the lignite ZrO 2 -GAC, while the one of bituminous ZrO 2 -GAC decreased. - Abstract: This study investigated the effects of in situ ZrO 2 nanoparticle formation on properties of granulated activated carbon (GAC) and their impacts on arsenic and organic co-contaminant removal. Bituminous and lignite based zirconium dioxide impregnated GAC (Zr-GAC) media were fabricated by hydrolysis of zirconium salt followed by annealing of the product at 400 o C in an inert environment. Media characterization suggested that GAC type does not affect the crystalline structure of the resulting ZrO 2 nanoparticles, but does affect zirconium content of the media, nanoparticle morphology, nanoparticle distribution, and surface area of Zr-GAC. The arsenic removal performance of both media was compared using 5 mM NaHCO 3 buffered ultrapure water and model groundwater containing competing ions, both with an initial arsenic C 0 ∼ 120 μg/L. Experimental outcomes suggested favorable adsorption energies and higher or similar adsorption capacities than commercially available or experimental adsorbents when compared on the basis of metal content. Short bed adsorber column tests showed that arsenic adsorption capacity decreases as a result of kinetics of competing ions. Correlation between the properties of the media and arsenic and methylene blue removal

  6. Exogenous bleaching evaluation on dentin using chemical activated technique compared with diode laser technique

    International Nuclear Information System (INIS)

    Carvalho, Breno Carnevalli Franco de

    2003-01-01

    This in vitro study compared the results of different exogenous bleaching proceedings on dentin after treatment of enamel surface. Thirty human canine were hewn preserving the vestibular half of the crown and 3 mm of root, showing a vestibular-lingual thickness average of 3,5 mm, measuring in the third middle of the crown. Ali teeth were maintained in wet chamber during the experiment. Digital photographs were taken of the dentin surface at 3 experimental times (LI: initial record, L0: immediate pos-bleaching record and L 15: 15 days after bleaching). The teeth were divided into 3 experimental groups of 10 teeth in each. The Control Group did not receive any kind of treatment. The Laser Group received 2 session of laser bleaching, with 3 applications each, using 35% hydrogen peroxide, activated by diode laser during 30 seconds, by scanning the enamel surface from incisal edge to the top of the crown, from mesial to distal portion of the crown and circularly, each movement during 10 seconds. The following parameters being adopted: wavelength of 808 nm, power of 1,5 W and optic fiber with 600 μm (core). The Peroxide Group received 28 daily applications, during 4 hours each application, using 16% carbamide peroxide. The bleaching records were analysed using a computer, through RGBK (red, green , blue and black). The K averages (K=100% for black and K=0% for white) of the records for Control Group were: LI=50,1 %, L0=50,3% and L 15=50,6%. For Laser Group the K averages were LI=48,5%, L0=50,0% and L 15=47,7%. And for the Peroxide Group were LI=50,5%, L0=35,9% and L 15=37,3%. The statistical analysis showed no significant difference of the K between the Control Group and the Laser Group, as to LI, L0 and L 15. Only Peroxide Group showed significant statistical difference between LI with L0 and L 15 (0,1%), and L0 in comparison with L 15 did not show any difference. (author)

  7. Social Media on the Job: An exploration of the potential legal consequences of employees’ social media activities during the course of employment.

    OpenAIRE

    Khan, Sarosh; Moore, Roksana; Weal, Mark

    2011-01-01

    This paper examines the current interplay between the actions of harassment and defamation and the nature and characteristics of social media specifically towards addressing the issues surrounding the growing usage of social media by employees during employment. It argues that with the legislation and provisions we currently have in place in the U.K. many problems are likely to arise for employers and employees alike as usage continues to rise.

  8. SOCIAL MEDIA

    Science.gov (United States)

    RESPONSIBILITY CENTCOM COALITION MEDIA SOCIAL MEDIA NEWS ARTICLES PRESS RELEASES IMAGERY VIDEOS TRANSCRIPTS VISITORS AND PERSONNEL FAMILY CENTER FAMILY READINESS CENTCOM WEBMAIL SOCIAL MEDIA SECURITY ACCOUNTABILITY HomeMEDIASOCIAL MEDIA Social Media CENTCOM'S ENGLISH SOCIAL MEDIA ACCOUNTS There are many U.S. military commands

  9. Integrating Airborne and Terrestrial Laser Scanning data to monitor active landsliding

    Science.gov (United States)

    Székely, B.; Molnár, G.; Roncat, A.; Lehner, H.; Gaisecker, Th.; Drexel, P.

    2009-04-01

    Active slope processes often endanger various built-up objects and, as a consequence, sometimes human lives as well. Data acquision on the status and evolution of such slopes, especially those that had already affected by landsliding, therefore is a primary target for engineering geomorphic research. The method of laser scanning provides an appropriate data collection technique with the requested accuracy. Data from repeated Airborne Laser Scanning (ALS) campaigns are suitable to be analysed for the slow, incipient movements of the slope. The problem of this surveying technique is that repetition time is strongly dependent on the financial resources of the monitoring project, and often the requested recurrence of flight campaigns cannot be achieved. A possible solution to densify the data acquisition in time is the application of Terrestrial Laser Scanning (TLS) and intergration of its data with ALS data sets. TLS has the advantage of flexibility and shorter observation distances compared to ALS. This technique needs special considerations and tedious processing since the geometric setting of the data acquision considerably differ in TLS and ALS. Furthermore, obstacles in the landscape may partly hamper the data acqusition which rarely the case in ALS. Our case study area is a several-decade-long active landsliding in Doren (Federal State Vorarlberg, Austria) that as it develops, it is about to endangers houses of the locality. The site is especially suitable for the project, because multi-temporal data sets (from ALS flight campaigns in 2003, 2006 and 2007, respectively) of this area are available. The data integration is carried out in the form of production of point clouds (sensed from various points of the valley sides) and we compared the results with the results of the previous ALS campaigns. With the planned repetition of the TLS measurements new and detailed insights can be achieved concerning the evolution of the incipient and on-going slow motions. This

  10. Study of New FNAL-NICADD Extruded Scintillator as Active Media of Large EMCal of ALICE at LHC

    CERN Document Server

    Grachov, Oleg A.; Pla-Dalmau, A.; Bross, A.; Rykalin, V.

    2006-01-01

    The current conceptual design of proposed Large EMCal of ALICE at LHC is based largely on the scintillating mega-tile/fiber technology implemented in CDF Endplug upgrade project and in both barrel and endcap electromagnetic calorimeters of the STAR. The cost of scintillating material leads us to the choice of extruded polystyrene based scintillator, which is available in new FNAL-NICADD facility. Result of optical measurements, such as light yield and light yield variation, show that it is possible to use this material as active media of Large EMCal of ALICE at LHC.

  11. Injection current minimization of InAs/InGaAs quantum dot laser by optimization of its active region and reflectivity of laser cavity edges

    International Nuclear Information System (INIS)

    Korenev, V V; Savelyev, A V; Zhukov, A E; Maximov, M V

    2015-01-01

    The ways to optimize key parameters of active region and edge reflectivity of edge- emitting semiconductor quantum dot laser are provided. It is shown that in the case of optimal cavity length and sufficiently large dispersion lasing spectrum of a given width can be obtained at injection current up to an order of magnitude lower in comparison to non-optimized sample. The influence of internal loss and edge reflection is also studied in details. (paper)

  12. Injection current minimization of InAs/InGaAs quantum dot laser by optimization of its active region and reflectivity of laser cavity edges

    Science.gov (United States)

    Korenev, V. V.; Savelyev, A. V.; Zhukov, A. E.; Maximov, M. V.

    2015-11-01

    The ways to optimize key parameters of active region and edge reflectivity of edge- emitting semiconductor quantum dot laser are provided. It is shown that in the case of optimal cavity length and sufficiently large dispersion lasing spectrum of a given width can be obtained at injection current up to an order of magnitude lower in comparison to non-optimized sample. The influence of internal loss and edge reflection is also studied in details.

  13. The effect of excimer laser pretreatment on diffusion and activation of boron implanted in silicon

    International Nuclear Information System (INIS)

    Monakhov, E.V.; Svensson, B.G.; Linnarsson, M.K.; La Magna, A.; Italia, M.; Privitera, V.; Fortunato, G.; Cuscuna, M.; Mariucci, L.

    2005-01-01

    We have investigated the effect of excimer laser annealing (ELA) on transient enhanced diffusion (TED) and activation of boron implanted in Si during subsequent rapid thermal annealing (RTA). It is observed that ELA with partial melting of the implanted region causes reduction of TED in the region that remains solid during ELA, where the diffusion length of boron is reduced by a factor of ∼4 as compared to the as-implanted sample. This is attributed to several mechanisms such as liquid-state annealing of a fraction of the implantation induced defects, introduction of excess vacancies during ELA, and solid-state annealing of the defects beyond the maximum melting depth by the heat wave propagating into the Si wafer. The ELA pretreatment provides a substantially improved electrical activation of boron during subsequent RTA

  14. Two dimensional visible-light-active Pt-BiOI photoelectrocatalyst for efficient ethanol oxidation reaction in alkaline media

    Science.gov (United States)

    Zhai, Chunyang; Hu, Jiayue; Sun, Mingjuan; Zhu, Mingshan

    2018-02-01

    Two dimensional (2D) BiOI nanoplates were synthesized and used as support for the deposition of Pt nanoparticles. Owing to broad visible light absorption (up to 660 nm), the as-obtained Pt-BiOI electrode was used as effective photoelectrocatalyst in the application of catalytic ethanol oxidation in alkaline media under visible light irradiation. Compared to dark condition, the Pt-BiOI modified electrode displayed 3 times improved catalytic activity towards ethanol oxidation under visible light irradiation. The synergistic effect of electrocatalytic and photocatalytic, and the unique of 2D structures contribute to the improvement of catalytic activity. The mechanism of enhanced photoelectrocatalytic process is proposed. The present results suggest that 2D visible-light-activated BiOI can be served as promising support for the decoration of Pt and applied in the fields of photoelectrochemical and photo-assisted fuel cell applications

  15. Dopant redistribution and electrical activation in silicon following ultra-low energy boron implantation and excimer laser annealing

    International Nuclear Information System (INIS)

    Whelan, S.; La Magna, A.; Privitera, V.; Mannino, G.; Italia, M.; Bongiorno, C.; Fortunato, G.; Mariucci, L.

    2003-01-01

    Excimer laser annealing (ELA) of ultra-low-energy (ULE) B-ion implanted Si has been performed. High-resolution transmission electron microscopy has been used to assess the as-implanted damage and the crystal recovery following ELA. The electrical activation and redistribution of B in Si during ELA has been investigated as a function of the laser energy density (melted depth), the implant dose, and the number of laser pulses (melt time). The activated and retained dose has been evaluated with spreading resistance profiling and secondary ion mass spectrometry. A significant amount of the implanted dopant was lost from the sample during ELA. However, the dopant that was retained in crystal material was fully activated following rapid resolidification. At an atomic concentration below the thermodynamic limit, the activation efficiency (dose activated/dose implanted into Si material) was a constant for a fixed melt depth, irrespective of the dose implanted and hence the total activated dose was raised as the implant dose was increased. The electrical activation was increased for high laser energy density annealing when the dopant was redistributed over a deeper range

  16. Explaining consumer brand-related activities on social media : An investigation of the different roles of self-expression and socializing motivations

    NARCIS (Netherlands)

    de Vries, Lisette; Peluso, A.M.; Romani, S.; Leeflang, Pieter; Marcati, A.

    2017-01-01

    People undertake various brand-related activities on social media that differ in levels of engagement. Companies, however, want to know how to motivate consumers to become involved in the relatively more engaging activities, as such activities are more likely to lead to increased sales. In this

  17. Analysis of media coverage and KINS communication activities on Fukushima accident

    International Nuclear Information System (INIS)

    Lee, Ki Hyung; Hwang, Sun Chul; Yun, Yuen Wha; Lee, Gye Hwi; Jeong, Jin A; Song, Hye Rim; Yang, Cho Hee

    2012-01-01

    The people and mass media of Korea, the closest country to Japan, showed great interest in Fukushima nuclear power plant accident. The Korean government and KINS (Korea Institute of Nuclear Safety) attempted to provide accurate information to the press through various communication actions. In this study, we conducted an in-depth analysis of the tendencies of the press according to the accident sequence and tracked the diffusion of this issue. The purpose of this study is to determine the properties of the crisis and essence of the issue. We also carry out a general evaluation and draw implications through an analysis of the communication actions of KINS

  18. CLASSICAL MEDIA RELATIONS AND NEW MEDIA RELATIONS IN SPORT

    Directory of Open Access Journals (Sweden)

    Alexandru Lucian MIHAI

    2014-06-01

    Full Text Available Media relations in sport mean maintenance of networks and positive relationships with people in the media to obtain positive media exposure for a sport product (informal and formal information sessions with media representatives. Because of the pervasive influence the media has on marketing success, sport marketers must make concerted efforts to create a positive relationship between their sport event and the media. They may accomplish this by providing the media with press releases, having news conferences, having media-day events (in which the media are invited to interact with the players, coaches, and administrators, providing media guides for the respective sport events and so on. Each of these activities promotes active involvement from the media, which will subsequently contribute to relationship building with the community.

  19. Advanced lasers for fusion

    International Nuclear Information System (INIS)

    Krupke, W.F.; George, E.V.; Haas, R.A.

    1979-01-01

    Laser drive systems' performance requirements for fusion reactors are developed following a review of the principles of inertial confinement fusion and of the technical status of fusion research lasers (Nd:glass; CO 2 , iodine). These requirements are analyzed in the context of energy-storing laser media with respect to laser systems design issues: optical damage and breakdown, medium excitation, parasitics and superfluorescence depumping, energy extraction physics, medium optical quality, and gas flow. Three types of energy-storing laser media of potential utility are identified and singled out for detailed review: (1) Group VI atomic lasers, (2) rare earth solid state hybrid lasers, and (3) rare earth molecular vapor lasers. The use of highly-radiative laser media, particularly the rare-gas monohalide excimers, are discussed in the context of short pulse fusion applications. The concept of backward wave Raman pulse compression is considered as an attractive technique for this purpose. The basic physics and device parameters of these four laser systems are reviewed and conceptual designs for high energy laser systems are presented. Preliminary estimates for systems efficiencies are given. (Auth.)

  20. Analytic study of the chain dark decomposition reaction of iodides - atomic iodine donors - in the active medium of a pulsed chemical oxygen-iodine laser: 1. Criteria for the development of the branching chain dark decomposition reaction of iodides

    International Nuclear Information System (INIS)

    Andreeva, Tamara L; Kuznetsova, S V; Maslov, Aleksandr I; Sorokin, Vadim N

    2009-01-01

    The scheme of chemical processes proceeding in the active medium of a pulsed chemical oxygen-iodine laser (COIL) is analysed. Based on the analysis performed, the complete system of differential equations corresponding to this scheme is replaced by a simplified system of equations describing in dimensionless variables the chain dark decomposition of iodides - atomic iodine donors, in the COIL active medium. The procedure solving this system is described, the basic parameters determining the development of the chain reaction are found and its specific time intervals are determined. The initial stage of the reaction is analysed and criteria for the development of the branching chain decomposition reaction of iodide in the COIL active medium are determined. (active media)

  1. Nucleophilic addition of amines to the activated ethylene bond in non-aqueous media

    International Nuclear Information System (INIS)

    Perepichka, Igor F.; Popov, Anatolii F.

    1995-01-01

    The kinetics of addition of a number of primary and secondary aliphatic amines to trans-(2-furyl) nitro ethylene (1) has been studied in solvents of various polarities (from acetonitrile, ε 37.5, to heptane, ε 1.89). It has been shown that the reaction is catalysed both by the amine reagent and by tertiary amines. On the basis of analyzing the observed kinetic regularities a stepwise reaction mechanism has been proposed which involves formation of zwitterionic intermediate (3) at the first equilibrium step (k 1 , K 1 ) which is then converted into the reaction product by means of proton transfer in parallel routes, the non-catalytic one (k 2 ) and that catalysed by the initial (K 3 ) or tertiary (K 4 ) amine. The observed high values of the deuterium isotope effects in the reaction (K H /K D ∼ 2.3 - 8.9) confirm that proton transfer occurs in the rate-limiting step of the reaction (primary kinetic isotope effect). The third order by amine kinetic route is observed in low polar media which is due to participation of amine dimers (R 2 NH HNR 2 ) in the reaction. The observed kinetic regularities are compared with those for the nucleophilic aromatic substitution reactions in low-polar media, and the conclusion has been made that the reaction route of the third order by amine proceeds as reversible nucleophilic attack by amine dimer and following base-catalysed transformation of the intermediate into the product. (author)

  2. Induced polarization and self-potential geophysical signature of bacterial activity in porous media (Invited)

    Science.gov (United States)

    Revil, A.

    2013-12-01

    The first part of the presentation will be dedicated to the spectral induced polarization signature of bacteria in porous media. We developed a quantitative model to investigate frequency-domain induced polarization response of suspensions of bacteria and bacteria growth in porous media. Induced polarization of bacteria (alpha-polarization) is related to the properties of the electrical double layer of the bacteria. Surface conductivity and alpha-polarization are due to the Stern layer of counterions occurring in a brush of polymers coating the surface of the bacteria. These phenomena can be related to the cation exchange capacity of the bacteria. The mobility of the counterions in this Stern layer is found to be very small (4.7×10-10 m2s-1 V-1 at 25°C). This implies a very low relaxation frequency for the alpha-polarization of the bacteria cells (typically around 0.1 to 5 Hertz) in agreement with experimental observations. This new model can be coupled to reactive transport modeling codes in which the evolution of bacterial populations are usually described by Monod kinetics. We show that the growth rate and endogenous decay coefficients of bacteria in a porous sand can be inferred non-intrusively from time lapse frequency-domain induced polarization data. The second part of the presentation will concern the biogeobattery mechanism showing new data, the concept of transient biogeobattery and the influence of the concentration of the electron acceptors in the process.

  3. Measurement of laser activated electron tunneling from semiconductor zinc oxide to adsorbed organic molecules by a matrix assisted laser desorption ionization mass spectrometer

    International Nuclear Information System (INIS)

    Zhong Hongying; Fu Jieying; Wang Xiaoli; Zheng Shi

    2012-01-01

    Highlights: ► Irradiation of photons with energies more than the band gap generates electron–hole pairs. ► Electron tunneling probability is dependent on the electron mobility. ► Tunneling electrons are captured by charge deficient atoms. ► Unpaired electrons induce cleavages of chemical bonds. - Abstract: Measurement of light induced heterogeneous electron transfer is important for understanding of fundamental processes involved in chemistry, physics and biology, which is still challenging by current techniques. Laser activated electron tunneling (LAET) from semiconductor metal oxides was observed and characterized by a MALDI (matrix assisted laser desorption ionization) mass spectrometer in this work. Nanoparticles of ZnO were placed on a MALDI sample plate. Free fatty acids and derivatives were used as models of organic compounds and directly deposited on the surface of ZnO nanoparticles. Irradiation of UV laser (λ = 355 nm) with energy more than the band gap of ZnO produces ions that can be detected in negative mode. When TiO 2 nanoparticles with similar band gap but much lower electron mobility were used, these ions were not observed unless the voltage on the sample plate was increased. The experimental results indicate that laser induced electron tunneling is dependent on the electron mobility and the strength of the electric field. Capture of low energy electrons by charge-deficient atoms of adsorbed organic molecules causes unpaired electron-directed cleavages of chemical bonds in a nonergodic pathway. In positive detection mode, electron tunneling cannot be observed due to the reverse moving direction of electrons. It should be able to expect that laser desorption ionization mass spectrometry is a new technique capable of probing the dynamics of electron tunneling. LAET offers advantages as a new ionization dissociation method for mass spectrometry.

  4. Anomalous dependence of the lasing parameters of dye solutions on the spectrum of microsecond pump laser pulses

    International Nuclear Information System (INIS)

    Tarkovsky, V V; Kurstak, V Yu; Anufrik, S S

    2003-01-01

    The anomalous dependence of the lasing parameters of ethanol solutions of coumarin, rhodamine, oxazine, and laser dyes of other classes on the spectrum of microsecond pump laser pulses is found. The dependence is determined by the shape of the induced singlet - singlet absorption spectra and absorption spectra of short-lived photoproducts. The elucidation of the influence of these factors makes it possible to choose optimal pump spectra and to enhance the efficiency and stability of microsecond dye lasers. (active media)

  5. Liquid chromatography automatic system with optical activity laser detector and its applications

    International Nuclear Information System (INIS)

    Fajer, V.; Naranjo, S.; Fernandez, H.; Mora, W.; Cepero, T.; Arista, E.; Mesa, G.; Cossio, G.; Arreche, J.; Fonfria, C.; Rodriguez, C.W.

    2009-01-01

    A new liquid chromatographic system with polarimetric detection and a computer program allowing the output of chromatograms to a display on line and electronic data storing was designed, built and put to work. The chromatographic system includes the laser polarimetric detector, having a measuring interval of one second, the chromatographic columns, the continuous flux polarimeter tubes of 50 and 100 mm, the programs for data acquisition, processing and storing, and the technical know-how for its most efficiently application. Thirty minutes is all the time needed to obtain a chromatogram by this method which is reasonably shorter than the time required for any other known comparable technique, and offering, besides, lower operation cost. The combination of molecular exclusion liquid chromatography and laser polarimetric detection has turned into a carbohydrate separation and quantification system of basic importance for the evaluation of plants fluids of industrial interest (sugarcane, agave, vegetable extracts, etc.). It is described here the application of this system as an early or complementary indicator of leaf scald -disease that affects sugarcane plants-. Another application on algae extracts gave good results in the separation and identification of biologically active components. The introduction of this system in several research centers in Cuba and abroad has resulted in practical information for the industry. (Author)

  6. Long-range active retroreflector to measure the rotational orientation in conjunction with a laser tracker

    Science.gov (United States)

    Hofherr, O.; Wachten, Christian; Müller, C.; Reinecke, H.

    2014-11-01

    High precision optical non-contact position measurement is a key technology in modern engineering. Laser trackers (LT) accurately determine x-y-z coordinates of passive retroreflectors. Next-generation systems answer the need to measure an object`s rotational orientation (pitch, yaw, roll). So far, these devices are based either on photogrammetry or on enhanced retroreflectors. Here we present a new method to measure all six degrees of freedom in conjunction with a LT. The basic principle is to analyze the orientation to the LT's beam path by coupling-out laser radiation. The optical design is inspired by a cat's eye retroreflector equipped with an integrated beam splitter layer. The optical spherical aberration is compensated, which reduces the divergence angle for the reflected beam by one order of magnitude compared to an uncompensated standard system of the same size. The wave front distortion is reduced to less than 0.1 λ @ 633 nm for beam diameters up to 8 mm. Our active retroreflector is suitable for long-range measurements for a distance > 10 m.

  7. Activation induced changes in GABA: Functional MRS at 7T with MEGA-sLASER.

    Science.gov (United States)

    Chen, Chen; Sigurdsson, Hilmar P; Pépés, Sophia E; Auer, Dorothee P; Morris, Peter G; Morgan, Paul S; Gowland, Penny A; Jackson, Stephen R

    2017-08-01

    Functional magnetic resonance spectroscopy (fMRS) has been used to assess the dynamic metabolic responses of the brain to a physiological stimulus non-invasively. However, only limited information on the dynamic functional response of γ-aminobutyric acid (GABA), the primary inhibitory neurotransmitter in the brain, is available. We aimed to measure the activation-induced changes in GABA unambiguously using a spectral editing method, instead of the conventional direct detection techniques used in previous fMRS studies. The Mescher-Garwood-semi-localised by adiabatic selective refocusing (MEGA-sLASER) sequence was developed at 7T to obtain the time course of GABA concentration without macromolecular contamination. A significant decrease (-12±5%) in the GABA to total creatine ratio (GABA/tCr) was observed in the motor cortex during a period of 10min of hand-clenching, compared to an initial baseline level (GABA/tCr =0.11±0.02) at rest. An increase in the Glx (glutamate and glutamine) to tCr ratio was also found, which is in agreement with previous findings. In contrast, no significant changes in NAA/tCr and tCr were detected. With consistent and highly efficient editing performance for GABA detection and the advantage of visually identifying GABA resonances in the spectra, MEGA-sLASER is demonstrated to be an effective method for studying of dynamic changes in GABA at 7T. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Tracking on non-active collaborative objects from San Fernando Laser station

    Science.gov (United States)

    Catalán, Manuel; Quijano, Manuel; Cortina, Luis M.; Pazos, Antonio A.; Martín-Davila, José

    2016-04-01

    The Royal Observatory of the Spanish Navy (ROA) works on satellite geodesy from the early days of the space age, when the first artificial satellite tracking telescope was installed in 1958: the Baker-Nunn camera. In 1975 a French satellite Laser ranging (SLR) station was installed and operated at ROA . Since 1980, ROA has been operating this instrument which was upgraded to a third generation and it is still keep into a continuous update to reach the highest level of operability. Since then ROA has participated in different space geodesy campaigns through the International Laser Service Stations (ILRS) or its European regional organization (EUROLAS), tracking a number of artificial satellites types : ERS, ENVISAT, LAGEOS, TOPEX- POSEIDON to name but a few. Recently we opened a new field of research: space debris tracking, which is receiving increasing importance and attention from international space agencies. The main problem is the relatively low accuracy of common used methods. It is clear that improving the predicted orbit accuracy is necessary to fulfill our aims (avoiding unnecessary anti-collision maneuvers,..). Following results obtained by other colleagues (Austria, China, USA,...) we proposed to share our time-schedule using our satellite ranging station to obtain data which will make orbital elements predictions far more accurate (sub-meter accuracy), while we still keep our tracking routines over active satellites. In this communication we report the actions fulfill until nowadays.

  9. Purification and characterization of a novel anti-HSV-2 protein with antiproliferative and peroxidase activities from Stellaria media

    Institute of Scientific and Technical Information of China (English)

    Yu Shan; Yuhong Zheng; Fuqin Guan; Jianjian Zhou; Haiguang Zhao; Bing Xia; Xu Feng

    2013-01-01

    A novel antiviral protein,designated as Stellarmedin A,was purified from Stellaria media (L.) Vill.(Caryophyllaceae) by using ammonium sulfate precipitation,cation-exchange chromatography system.Gel electrophoresis analysis showed that Stellarmedin A is a highly basic glycoprotein with a molecular weight of 35.1 kDa and an isoelectric point of ~8.7.The Nterminal 14-amino acid sequence,MGNTGVLTGERNDR,is similar to those of other plant peroxidases.This protein inhibited herpes simplex virus type 2 (HSV-2) replication in vitro with an ICso of 13.18 μg/ml and a therapeutic index exceeding 75.9.It was demonstrated that Stellarmedin A affects the initial stage of HSV-2 infection and is able to inhibit the proliferation of promyelocytic leukemia HL-60 and colon carcinoma LoVo cells with an ICso of 9.09 and 12.32 μM,respectively.Moreover,Stellarmedin A has a peroxidase activity of 36.6 μmol/min/mg protein,when gualacol was used as substrate.To our knowledge,this is the first report about an anti-HSV-2 protein with antiproliferative and peroxidase activities from S.media.

  10. Systematic analysis of DNA damage induction and DNA repair pathway activation by continuous wave visible light laser micro-irradiation

    Directory of Open Access Journals (Sweden)

    Britta Muster

    2017-02-01

    Full Text Available Laser micro-irradiation can be used to induce DNA damage with high spatial and temporal resolution, representing a powerful tool to analyze DNA repair in vivo in the context of chromatin. However, most lasers induce a mixture of DNA damage leading to the activation of multiple DNA repair pathways and making it impossible to study individual repair processes. Hence, we aimed to establish and validate micro-irradiation conditions together with inhibition of several key proteins to discriminate different types of DNA damage and repair pathways using lasers commonly available in confocal microscopes. Using time-lapse analysis of cells expressing fluorescently tagged repair proteins and also validation of the DNA damage generated by micro-irradiation using several key damage markers, we show that irradiation with a 405 nm continuous wave laser lead to the activation of all repair pathways even in the absence of exogenous sensitization. In contrast, we found that irradiation with 488 nm laser lead to the selective activation of non-processive short-patch base excision and single strand break repair, which were further validated by PARP inhibition and metoxyamine treatment. We conclude that these low energy conditions discriminated against processive long-patch base excision repair, nucleotide excision repair as well as double strand break repair pathways.

  11. Research activities in our laser R and D group (present and future)

    International Nuclear Information System (INIS)

    Sugiyama, Akira; Kondo, Kiminori; Kiriyama, Hiromitsu; Ochi, Yoshihiro; Tanaka, Momoko; Nakai, Yoshiki; Sasao, Hajime; Tateno, Ryo; Okada, Hajime; Koike, Masato

    2010-01-01

    Our group has been newly established in this April to develop next high peak power laser systems which can be used for innovative applications. We have developed essential technologies for the upgrade of laser performances in J-KAREN and TOPAZ laser systems in order to supply these advanced laser beams for application studies such as laser acceleration, high optical field science, highly intense X-ray generation, and so on. In the development of J-KAREN laser, we achieved high contrast ratio of over 10 10 by employing OPCPA technique. While in the TOPAZ laser, 0.1 Hz operation was realized with a development of zigzag slab type glass laser which can reduce thermal distortion inside the excited laser medium. This repetition rate was increased by two orders of magnitude compared to previous rod type glass laser system. Using the TOPAZ laser, we have succeeded to generate 13.9-nm x-ray laser beam with beam divergence less than 0.5 mrad at a repetition rate of 0.1 Hz. (author)

  12. Experimental investigation of the effect of HBr additions on the lasing characteristics of a CuBr laser

    International Nuclear Information System (INIS)

    Shiyanov, D V; Sukhanov, V B; Andrienko, Oleg S; Evtushenko, Gennadii S

    2004-01-01

    It was experimentally determined that introducing small additions of HBr into the active elements of a CuBr laser is similar to the addition of hydrogen and significantly improves the output laser parameters. The effect of additions to small-volume active elements is most pronounced (up to a five-fold increase in output power) and is less pronounced in large-volume active elements (up to a twofold increase). A special-purpose HBr generator was elaborated, making it possible to promptly provide the requisite concentration of the active addition in a sealed-off active element. (lasers, active media)

  13. Effect of active-region “volume” on the radiative properties of laser heterostructures with radiation output through the substrate

    Energy Technology Data Exchange (ETDEWEB)

    Nekorkin, S. M.; Zvonkov, B. N.; Baidus, N. V.; Dikareva, N. V., E-mail: dnat@ro.ru; Vikhrova, O. V. [Nizhny Novgorod State University, Physicotechnical Research Institute (Russian Federation); Afonenko, A. A.; Ushakov, D. V. [Belarussian State University (Belarus)

    2017-01-15

    The radiative properties of InGaAs/GaAs/InGaP laser structures with radiation output through the substrate depending on the number of quantum wells in the active region and laser diodes on their basis are investigated. It is established that the presence of six–eight quantum wells in the active region is optimum from the viewpoint of observable values of the threshold current and the output optical power of lasers.

  14. Role of spiral wave pinning in inhomogeneous active media in the termination of atrial fibrillation by electrical cardioversion.

    Science.gov (United States)

    Kuklik, Pawel; Wong, Christopher X; Brooks, Anthony G; Zebrowski, Jan Jacek; Sanders, Prashanthan

    2010-03-01

    Atrial fibrillation is the most common type of arrhythmia to affect humans. One of the treatment modalities for atrial fibrillation is an electrical cardioversion. Electrical cardioversion can result in one of three outcomes: an immediate termination of arrhythmic activity, a delayed termination or unsuccessful termination. The mechanism of delayed termination is unknown. Here we present a model of an atrial fibrillation as a coexistence of several spiral waves pinned to the inhomogeneities in active media. We show that in inhomogeneous system delayed termination can be explained as the unpinning of a spiral wave from inhomogeneities and its termination after collision with the edge of the system. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  15. When static media promote active learning: annotated illustrations versus narrated animations in multimedia instruction.

    Science.gov (United States)

    Mayer, Richard E; Hegarty, Mary; Mayer, Sarah; Campbell, Julie

    2005-12-01

    In 4 experiments, students received a lesson consisting of computer-based animation and narration or a lesson consisting of paper-based static diagrams and text. The lessons used the same words and graphics in the paper-based and computer-based versions to explain the process of lightning formation (Experiment 1), how a toilet tank works (Experiment 2), how ocean waves work (Experiment 3), and how a car's braking system works (Experiment 4). On subsequent retention and transfer tests, the paper group performed significantly better than the computer group on 4 of 8 comparisons, and there was no significant difference on the rest. These results support the static media hypothesis, in which static illustrations with printed text reduce extraneous processing and promote germane processing as compared with narrated animations.

  16. Utilization of surface active sites on gold in preparation of highly reactive interfaces for alcohols electrooxidation in alkaline media

    International Nuclear Information System (INIS)

    Cherevko, Serhiy; Kulyk, Nadiia; Chung, Chan-Hwa

    2012-01-01

    Graphical abstract: - Abstract: Pt/Au and Pd/Au surface interfaces show very high activity in electrocatalytic oxidation of alcohols in alkaline media. In this work, we present a method for preparation of such structures, which is based on galvanic displacement of the more noble gold with the less noble elements, and investigate their electrocatalytic properties. We propose that active states atoms on the surface of gold may be replaced with Pt and Pd. The generation of active sites on gold is achieved by cathodization in acidic solution. We show that depending on the cathodization time (active sites amount) gold surface electrochemistry changes from that resembling Au to the one typical for pure Pt. The Pt/Au structures prepared with a trace amount of platinum show extremely high electrocatalytic activity. The peak current of methanol oxidation on the Pt/Au electrode is more than an order of magnitude higher than that of the platinum film electrode and more than two orders of magnitude higher than that on the gold unactivated electrode. The difference in the peak current of ethanol oxidation between the Pt/Au and Pt electrodes is ca. 25 times. Moreover, similar deposition of Pt and Pd on active sites on high surface area gold prepared by hydrogen evolution assisted deposition and improved electrocatalytic properties of such structures toward alcohols oxidation is shown.

  17. Laser fluorescence on radio-active isotopes produced in very low yield

    International Nuclear Information System (INIS)

    Dancy, D.E.; Billowes, J.; Grant, I.S.; Evans, D.E.; Griffith, J.A.R.; Wells, S.A.; Eastham, D.A.; Groves, J.; Smith, J.R.H.; Tolfree, D.W.L.; Walker, P.M.

    1990-01-01

    Fast particle-photon coincidence techniques, developed at Daresbury with strontium isotopes, allow ultra-sensitive laser fluorescence spectroscopy of beams of radio-active isotopes which can only be produced in very low yields. The technique has now been applied to neutron-deficient barium isotopes down to 120 Ba. From measured hyperfine splitting and isotope shifts, nuclear moments and changes in mean square radii have been determined. The work has revealed an abrupt increase in the mean square radius for 121 Ba large enough to disrupt the systematic staggering of nuclear size seen for the series. In a recent experiment an isomeric state of 127 Ba with a half-life of about 2 seconds has been produced in a very low yield; nevertheless we have succeeded in obtaining a fluorescence spectrum. (orig.)

  18. Catalytic Activity of Silicon Nanowires Decorated with Gold and Copper Nanoparticles Deposited by Pulsed Laser Ablation

    Directory of Open Access Journals (Sweden)

    Michele Casiello

    2018-01-01

    Full Text Available Silicon nanowires (SiNWs decorated by pulsed laser ablation with gold or copper nanoparticles (labeled as AuNPs@SiNWs and CuNPs@SiNWs were investigated for their catalytic properties. Results demonstrated high catalytic performances in the Caryl–N couplings and subsequent carbonylations for gold and copper catalysts, respectively, that have no precedents in the literature. The excellent activity, attested by the very high turn over number (TON values, was due both to the uniform coverage along the NW length and to the absence of the chemical shell surrounding the metal nanoparticles (MeNPs. A high recyclability was also observed and can be ascribed to the strong covalent interaction at the Me–Si interface by virtue of metal “silicides” formation.

  19. Prosocial effects of media.

    Science.gov (United States)

    Hogan, Marjorie J

    2012-06-01

    Parents, teachers, health care providers, and other caring adults worry about the harmful influence of media messages and images on children and teens and wonder how to recognize and encourage positive and healthy use of media. For decades, experts have commented on the power of media. Media depictions can lead to negative attitudes and behavior in some young viewers. This article discusses whether prosocial, tolerant, and cooperative attitudes and behavior can be learned and imitated by children and adolescents and whether media can nurture or stimulate creativity or actively promote health and well-being in young consumers. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Heparanase-1 activities in the development of laser induced choroidal neovascularization

    Directory of Open Access Journals (Sweden)

    Bao-Ke Hou

    2013-04-01

    Full Text Available AIM:To investigate the role of heparanase-1 in laser-induced choroidal neovascularization (CNV.METHODS:Experimental CNV was induced by krypton laser photocoagulation in 15 male Brown Norway rats. Fundus fluorescein angiography and histopathological examination were performed in observing the CNV development. The expression and distribution of heparanase-1 protein in the laser lesions were determined by immunohistochemistry and western blotting analysis.RESULTS:The success rate of laser induced CNV was approximately 75% on 3-4 weeks after laser photocoagulation. The protein levels of heparanase-1 increased significantly in the retina-choroidal complex of CNV models when compared to normal rat eyes (P<0.01. Immunostaining confirmed strong heparanase-1 expressions in all laser lesions, and it displayed to be highest at the newly formed blood vessels within the fibrovascular complex in the subretinal space.CONCLUSION:Heparanase-1 is closely involved in the development of laser induced CNV.

  1. Activation of visible up-conversion luminescence in transparent and conducting ZnO:Er:Yb films by laser annealing

    International Nuclear Information System (INIS)

    Lluscà, M.; López-Vidrier, J.; Lauzurica, S.; Sánchez-Aniorte, M.I.; Antony, A.; Molpeceres, C.; Hernández, S.; Garrido, B.; Bertomeu, J.

    2015-01-01

    Transparent and conducting ZnO:Er:Yb thin films with visible up-conversion (660-nm emission under 980-nm excitation) were fabricated by RF magnetron sputtering. The as-deposited films were found to be transparent and conducting and the activation of the Er ions in these films to produce up-conversion luminescence was achieved by different post-deposition annealing treatments in air, vacuum or by laser annealing using a Nd:YVO 4 laser. The structural, electrical and optical properties and the up-conversion efficiency of these films were found to be strongly influenced by the annealing method, and a detailed study is reported in this paper. It has been demonstrated that, although the air annealing was the most efficient in terms of up-conversion, laser annealing was the only method capable of activating Er ions while preserving the electrical conductivity of the doped films. It has been shown that a minimum energy was needed in laser annealing to optically activate the rare earth ions in the ZnO host material to produce up-conversion. Up-converting and transparent conducting ZnO:Er:Yb films with an electrical resistivity of 5×10 −2 Ω cm and transparency ~80% in the visible wavelength range has been achieved by laser annealing. - Highlights: • Transparent and conducting ZnO:Er:Yb films were grown via magnetron sputtering. • Post-annealing ZnO:Er:Yb is needed to optically activate Er ions. • Visible up-conversion emission at 660 nm is observed under 980 nm excitation. • A transparent and conducting up-converter is achieved by laser annealing

  2. Study of mode locking in a microwave-pumped diode laser close to the generation threshold

    International Nuclear Information System (INIS)

    Bagaev, Sergei N; Zakharyash, Valerii F; Kashirsky, Aleksandr V; Klementyev, Vasilii M; Kuznetsov, Sergei A; Pivtsov, V S

    2004-01-01

    Active mode locking is studied in a diode laser with a three-mirror resonator upon the microwave modulation of the pump current. The mode-locking region with the minimal width of the spectrum of intermode beats is found, when the microwave frequency is close to the intermode frequency of an external resonator. This region is shown to be located close to the threshold pump current. (lasers, active media)

  3. Transparent Conducting Nb-Doped TiO2 Electrodes Activated by Laser Annealing for Inexpensive Flexible Organic Solar Cells

    Science.gov (United States)

    Lee, Jung-Hsiang; Lin, Chia-Chi; Lin, Yi-Chang

    2012-01-01

    A KrF excimer laser (λ= 248 nm) has been adopted for annealing cost-effective Nb-doped TiO2 (NTO) films. Sputtered NTO layers were annealed on SiO2-coated flexible poly(ethylene terephthalate) (PET) substrates. This local laser annealing technique is very useful for the formation of anatase NTO electrodes used in flexible organic solar cells (OSCs). An amorphous NTO film with a high resistivity and a low transparency was transformed significantly into a conductive and transparent anatase NTO electrode by laser irradiation. The 210 nm anatase NTO film shows a sheet resistance of 50 Ω and an average optical transmittance of 83.5% in the wavelength range from 450 to 600 nm after annealing at 0.25 J/cm2. The activation of Nb dopants and the formation of the anatase phase contribute to the high conductivity of the laser-annealed NTO electrode. Nb activation causes an increase in the optical band gap due to the Burstein-Moss effect. The electrical properties are in agreement with the material characteristics determined by X-ray diffraction (XRD) analysis and secondary ion mass spectrometry (SIMS). The irradiation energy for the NTO electrode also affects the performance of the organic solar cell. The laser annealing technique provides good properties of the anatase NTO film used as a transparent electrode for flexible organic solar cells (OSCs) without damage to the PET substrate or layer delamination from the substrate.

  4. OMBUDSMEN IN THE BRAZILIAN AND PORTUGUESE MEDIA: A REFLECTION ON THE ACTIVITIES DEVELOPED BETWEEN 1989 AND 2013

    Directory of Open Access Journals (Sweden)

    Fernando Oliveira Paulino

    2014-06-01

    Full Text Available This article aims to reflect on the history of the practices of ombudsmen in the Brazilian and Portuguese media, seeking simultaneously to identify the challenges and difficulties inherent to this function in mediatic communication. A comparative approach is adopted here, which, as is generally the case in social science, seeks to discover regularities and recognize differences in the activities developed by the ombudsmen in Brazil and Portugal between 1989 and 2013. Hence, using comparison to obtain a method to objectify the analysis, this study purports to outline the function in communication vehicles in both countries. With almost 25 years’ existence in the lusophone sphere and, despite having properties such as the accountability mechanism, hetero- and auto-regulation, the ombudsman has not been widely adopted in Portuguese-speaking countries. In Brazil, the expansion of the function is still conceivable, while in Portugal, the ombudsman is an instrument undergoing steady decline. Affected by the European economic crisis, the Portuguese media have resisted the establishment of the institution  and those who have already accepted it seem to be abandoning it progressively.

  5. Automatic media-adventitia IVUS image segmentation based on sparse representation framework and dynamic directional active contour model.

    Science.gov (United States)

    Zakeri, Fahimeh Sadat; Setarehdan, Seyed Kamaledin; Norouzi, Somayye

    2017-10-01

    Segmentation of the arterial wall boundaries from intravascular ultrasound images is an important image processing task in order to quantify arterial wall characteristics such as shape, area, thickness and eccentricity. Since manual segmentation of these boundaries is a laborious and time consuming procedure, many researchers attempted to develop (semi-) automatic segmentation techniques as a powerful tool for educational and clinical purposes in the past but as yet there is no any clinically approved method in the market. This paper presents a deterministic-statistical strategy for automatic media-adventitia border detection by a fourfold algorithm. First, a smoothed initial contour is extracted based on the classification in the sparse representation framework which is combined with the dynamic directional convolution vector field. Next, an active contour model is utilized for the propagation of the initial contour toward the interested borders. Finally, the extracted contour is refined in the leakage, side branch openings and calcification regions based on the image texture patterns. The performance of the proposed algorithm is evaluated by comparing the results to those manually traced borders by an expert on 312 different IVUS images obtained from four different patients. The statistical analysis of the results demonstrates the efficiency of the proposed method in the media-adventitia border detection with enough consistency in the leakage and calcification regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Improving the quality and impact of public health social media activity in Scotland during 2016: #ScotPublicHealth.

    Science.gov (United States)

    Mackenzie, Douglas Graham

    2017-06-07

    Social media, including Twitter, potentially provides a route to communicate public health messages to a large audience. Simple measures can boost onward broadcast to other users ('retweeting'). This study compares the impact of a structured programme of social media activity in Scotland during 2016 (using #ScotPublicHealth hashtag) with previous years. The Twitter search function was used to identify tweets between 2014 and 2016 inclusive. The first three tweets from each Twitter user were selected for each period. The number of retweets was used as a measure of impact. The quality of tweets was assessed by recording use of image, weblink (uniform resource locator or URL), mention of another Twitter user and/or hashtag, each of which have been shown to boost number of retweets. The percentage of tweets with an image, URL and/or mention of another Twitter user increased during the period of study. The percentage of tweets retweeted during Scottish Public Health conferences increased from 43% in 2014 to 70% in 2016. The volume of tweeting also increased. The quality and impact of tweets sent by the Scottish Public Health community was higher during 2016 than previous years. Conference tweeting remains an area for improvement. © The Author 2017. Published by Oxford University Press on behalf of Faculty of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  7. Ombudsmen in the Brazilian and Portuguese media: a reflection on the activities developed between 1989 and 2013

    Directory of Open Access Journals (Sweden)

    Fernando Oliveira Paulino

    2014-06-01

    Full Text Available This article aims to reflect on the history of the practices of ombudsmen in the Brazilian and Portuguese media, seeking simultaneously to identify the challenges and difficulties inherent to this function in mediatic communication. A comparative approach is adopted here, which, as is generally the case in social science, seeks to discover regularities and recognize differences in the activities developed by the ombudsmen in Brazil and Portugal between 1989 and 2013. Hence, using comparison to obtain a method to objectify the analysis, this study purports to outline the function in communication vehicles in both countries. With almost 25 years’ existence in the lusophone sphere and, despite having properties such as the accountability mechanism, hetero- and auto-regulation, the ombudsman has not been widely adopted in Portuguese-speaking countries. In Brazil, the expansion of the function is still conceivable, while in Portugal, the ombudsman is an instrument undergoing steady decline. Affected by the European economic crisis, the Portuguese media have resisted the establishment of the institution  and those who have already accepted it seem to be abandoning it progressively.

  8. Tunable laser applications

    CERN Document Server

    Duarte, FJ

    2008-01-01

    Introduction F. J. Duarte Spectroscopic Applications of Tunable Optical Parametric Oscillators B. J. Orr, R. T. White, and Y. He Solid-State Dye Lasers Costela, I. García-Moreno, and R. Sastre Tunable Lasers Based on Dye-Doped Polymer Gain Media Incorporating Homogeneous Distributions of Functional Nanoparticles F. J. Duarte and R. O. James Broadly Tunable External-Cavity Semiconductor Lasers F. J. Duarte Tunable Fiber Lasers T. M. Shay and F. J. Duarte Fiber Laser Overview and Medical Applications

  9. Forehead Skin Blood Flow in Normal Neonates during Active and Quiet Sleep, Measured with a Diode Laser Doppler Instrument

    NARCIS (Netherlands)

    Suichies, H.E.; Aarnoudse, J.G.; Okken, A.; Jentink, H.W.; de Mul, F.F.M.; Greve, Jan

    1988-01-01

    Changes in forehead skin blood flow during active and quiet sleep were determined in 16 healthy neonates using a recently developed semi-conductor laser Doppler flow meter without light conducting fibres. Measurements were carried out at a postnatal age varying from 5 hours to 7 days. The two sleep

  10. Sol-Gel Derived Active Material for Yb Thin-Disk Lasers.

    Science.gov (United States)

    Almeida, Rui M; Ribeiro, Tiago; Santos, Luís F

    2017-09-02

    A ytterbium doped active material for thin-disk laser was developed based on aluminosilicate and phosphosilicate glass matrices containing up to 30 mol% YbO 1.5 . Thick films and bulk samples were prepared by sol-gel processing. The structural nature of the base material was assessed by X-ray diffraction and Raman spectroscopy and the film morphology was evidenced by scanning electron microscopy. The photoluminescence (PL) properties of different compositions, including emission spectra and lifetimes, were also studied. Er 3+ was used as an internal reference to compare the intensities of the Yb 3+ PL peaks at ~ 1020 nm. The Yb 3+ PL lifetimes were found to vary between 1.0 and 0.5 ms when the Yb concentration increased from 3 to 30 mol%. Based on a figure of merit, the best active material selected was the aluminosilicate glass composition 71 SiO₂-14 AlO 1.5 -15 YbO 1.5 (in mol%). An active disk, ~ 36 μm thick, consisting of a Bragg mirror, an aluminosilicate layer doped with 15 mol% Yb and an anti-reflective coating, was fabricated.

  11. Effects of a mass media campaign to increase physical activity among children: year-1 results of the VERB campaign.

    Science.gov (United States)

    Huhman, Marian; Potter, Lance D; Wong, Faye L; Banspach, Stephen W; Duke, Jennifer C; Heitzler, Carrie D

    2005-08-01

    To determine the effects of a mass media campaign on the levels of physical activity among children 9 to 13 years of age. A prospective, longitudinal, quasi-experimental design was used. A baseline survey was conducted in April to June 2002, before the launch of VERB advertising. Random-digit-dialing methods were used to survey a nationally representative sample of children and parents. The follow-up survey was repeated with the same cohort of children and parents in April to June 2003. Propensity scoring was used to determine the campaign's effects on awareness and physical activity behaviors. United States. A total of 3120 parent-child dyads. Intervention. The VERB campaign is a multiethnic campaign that combines paid advertisements with school and community promotions and Internet activities to encourage children 9 to 13 years of age to be physically active every day. Launched in 2002 by the Centers for Disease Control and Prevention, VERB uses commercial marketing methods to advertise being physically active as cool, fun, and a chance to have a good time with friends. Using the VERB brand, paid advertising ran nationally from June 2002 through June 2003, targeting 9- to 13-year-old youths. Children's awareness of the campaign and self-reported estimates of free-time and organized physical activity sessions during nonschool hours in the week before the interview. After 1 year, 74% of children surveyed were aware of the VERB campaign. Levels of reported sessions of free-time physical activity increased for subgroups of children 9 to 13 years of age. A pattern of effects across 2 measures was observed for younger children (9-10 years of age), girls, children whose parents had less than a high school education, children from urban areas that were densely populated, and children who were low active at baseline. These subgroups engaged in more median weekly sessions of free-time physical activity than did children who were unaware of VERB and, as the children's level

  12. The motivation activation measure and media use in Singapore: Cross-cultural stability

    OpenAIRE

    Samson, L.; Detenber, B.H.

    2017-01-01

    The purpose of this paper is twofold: First, it tests how the Motivation Activation Measure [MAM; Lang, A., Bradley, S. D., Sparks Jr, J. V., & Lee, S. (2007). The motivation activation measure (MAM): How well does MAM predict individual differences in physiological indicators of appetitive and aversive activation? Communication Methods and Measures, 1(2), 113-136] applies in a non-American (i.e. Asian) context, in order to provide evidence for the universality asserted through its theoretica...

  13. Reconfigurable Optical Elements Based on Single and Coupled Microdisk Resonators with Quantum DOT Active Media

    Science.gov (United States)

    2012-06-29

    of active-passive integrated polymer waveguides. The active waveguides consist of CdSe quantum dots dispersed in SU8 . Bottom panel shows CCD images...successfully demonstrated (i) incorporation of CdSe QDs into polymer and dielectric host and realization of devices such as active waveguides, microdisk...the significant outcomes of the program: • Successful incorporation of CdSe QDs into polymer and dielectric host and realization of devices such as

  14. The nitrogen doping effect on the properties of Ge-In-Sb-Te phase-change recording media investigated by blue-light laser

    International Nuclear Information System (INIS)

    Yeh, T.-T.; Hsieh, T.-E.; Shieh, H.-P.D.

    2005-01-01

    This work investigates the thermal, optical and recrystallization properties as well as the microstructure of nitrogen-doped Ge-In-Sb-Te (GIST) phase-change material when irradiated by blue-light laser. The experimental results showed that nitrogen doping at the condition of N 2 /Ar sputtering gas flow ratio equals to 3% might enhance the recrystallization speed of GIST recording layer up to 1.5 times. However, the disk failed when too much nitrogen (N 2 /Ar ≥ 5.0%) was introduced. The data obtained by differential scanning calorimetry, X-ray diffraction and ellipsometry revealed changes of thermal and optical properties due to the nitrogen doping in GIST. When appropriate amount of nitrogen was added, the activation energy (E a ) of amorphous-crystalline phase transition of GIST decreased and the optical constants of amorphous and crystalline phases (except the k value of amorphous phase) gradually reduced with the increase of wavelength in the range of 600-750 nm. Modulation simulation based on the reflectively of doped GIST layers obtained from static test indicated that appropriate nitrogen doping benefited the signal characteristics of optical disks. Transmission electron microscopy observed numerous tiny precipitates uniformly distributed in the doped GIST layers. These were believed to be nitride particles generated by nitrogen doping that might offer the preferential sites for amorphous-crystalline phase transition so that the recrystallization speed was accelerated

  15. Pulsed-laser-activated impulse response encoder: Sensitive detection of surface elastic waves on biomimetic microsized gel spheres

    Science.gov (United States)

    Yasukuni, Ryohei; Fukushima, Ryosuke; Iino, Takanori; Hosokawa, Yoichiroh

    2017-11-01

    A femtosecond-laser-induced impulsive force was applied to microsized calcium alginate (CaAlg) gel spheres as an external force to excite elastic waves. To evaluate elasticity, atomic force microscopy (AFM) was applied to detect vibration propagation. The sphere size dependence of the vibration was well reproduced by finite element method (FEM) simulation for pressure waves and surface acoustic waves. The obtained results indicate that the pulsed-laser-activated impulse response encoder (PLAIRE) enables the sensitive detection of elasticities, not only on inside but also on the surface.

  16. [Changes in leisure activity among young people aged 15-18 years in Hungary: physical activity, media-consumption and smoking].

    Science.gov (United States)

    Takács, Bence

    2013-04-14

    Young people are more and more inactive, which has numerous well-known negative effects on their health. Several studies indicate that inactive lifestyle disposes people to sit in front of the television, which increases aggression and decreases the willingness of reading. There is also a strong link between inactivity and an increase of body mass, deterioration of anthropometric parameters, and deviant behaviour. The aim of the study was to find out, on the basis of two cross-sectional surveys, the changes occurred within eight years in the free-time activity of Hungarian young people aged between 15 and 19 years. Data obtained from two surveys conducted by the National Institute for Family and Social Policy, Hungary in 2000 and 2008 including 1780 and 2018 young people, respectively, were analysed and compared. The number of young people regularly involved in sport activity increased significantly, while their media-consumption failed to decrease. Physically active young people are more health-conscious, but regular sporting activity did not expel smoking, which was associated with a sedentary lifestyle and television watching. These data reveal new responses of a new generation; watching television still takes the largest part of their free time activity, but use of computers, and participation in social activities are not necessarily increase sedentary lifestyle and deviant habits. Internet has positive effects on the regularity of their physical activity.

  17. Clogging and depinning of ballistic active matter systems in disordered media

    Science.gov (United States)

    Reichhardt, C.; Reichhardt, C. J. O.

    2018-05-01

    We numerically examine ballistic active disks driven through a random obstacle array. Formation of a pinned or clogged state occurs at much lower obstacle densities for the active disks than for passive disks. As a function of obstacle density, we identify several distinct phases including a depinned fluctuating cluster state, a pinned single-cluster or jammed state, a pinned multicluster state, a pinned gel state, and a pinned disordered state. At lower active disk densities, a drifting uniform liquid forms in the absence of obstacles, but when even a small number of obstacles are introduced, the disks organize into a pinned phase-separated cluster state in which clusters nucleate around the obstacles, similar to a wetting phenomenon. We examine how the depinning threshold changes as a function of disk or obstacle density and find a crossover from a collectively pinned cluster state to a disordered plastic depinning transition as a function of increasing obstacle density. We compare this to the behavior of nonballistic active particles and show that as we vary the activity from completely passive to completely ballistic, a clogged phase-separated state appears in both the active and passive limits, while for intermediate activity, a readily flowing liquid state appears and there is an optimal activity level that maximizes the flux through the sample.

  18. Children, Extracurricular Activities, and Digital Media: The Process of Displacement and School Performance

    Science.gov (United States)

    Mourgela, Vasiliki; Pacurar, Ecaterina

    2018-01-01

    This work, situated in the Greek sociocultural context, attempts to analyze the time spent by primary school students on digital and traditional extracurricular activities and the impact of these activities on the educational outcome. The first objective was to determine, by means of a quantitative survey, if the children as "digital…

  19. The motivation activation measure and media use in Singapore: Cross-cultural stability

    NARCIS (Netherlands)

    Samson, L.; Detenber, B.H.

    2017-01-01

    The purpose of this paper is twofold: First, it tests how the Motivation Activation Measure [MAM; Lang, A., Bradley, S. D., Sparks Jr, J. V., & Lee, S. (2007). The motivation activation measure (MAM): How well does MAM predict individual differences in physiological indicators of appetitive and

  20. PENERAPAN METODE STUDENT ACTIVE LEARNING (SAL MELALUI MULTI MEDIA POWER POINT UNTUK MENINGKATKAN KEAKTIFAN, KETERAMPILAN BERDISKUSI, DAN HASIL BELAJAR MATEMATIKA

    Directory of Open Access Journals (Sweden)

    Rustinah Rustinah

    2017-08-01

    Full Text Available The purpose of this study is find math learning scenarios format with active student learning method of learning mathematics by using multimedia power point to determine how much influence can enhance the activity, discuss the skills and student learning outcomes. Subjects examined or samples studied were students who study at grade students geometry IX.2 SMP Negeri 3 Batanghari, East Lampung. This study occurred during the three months using three cycles. The variables measured in the study include the involvement of the student in the learning process, skills in using media power point and student learning outcomes. Conclusions of this research is that it can increase the creativity of teachers using a variety of learning resources and selection methods that can encourage the creation of a learning process student active learning with contextual approach through multimedia. Can enhance the activity, and fun atusiasme students during the learning process, improve students' skills in solving problems and improve learning outcomes, especially the material geometry.

  1. A tolerance analysis on design parameters of parabolic and hyperbolic secant active GRIN materials for laser beam shaping purposes

    International Nuclear Information System (INIS)

    Gómez-Varela, A I; Bao-Varela, C; Flores-Arias, M T

    2014-01-01

    The present paper considers two gain GRIN media, characterized by a complex parabolic and hyperbolic secant refractive index profile, for the design of uniform beam shaper systems. A general condition for beam shaping is obtained from the equation describing the evolution of the half-width of a plane Gaussian beam in the GRIN media. The simulation of the irradiance evolution of an input plane Gaussian beam—operating at 575 nm and beam waist radius of 0.45 mm—in each material is shown, in order to examine the beam shaping quality in terms of thickness of the active GRIN media and input beam wavelength. (paper)

  2. Bistable laser device with multiple coupled active vertical-cavity resonators

    Science.gov (United States)

    Fischer, Arthur J.; Choquette, Kent D.; Chow, Weng W.

    2003-08-19

    A new class of bistable coupled-resonator vertical-cavity semiconductor laser devices has been developed. These bistable laser devices can be switched, either electrically or optically, between lasing and non-lasing states. A switching signal with a power of a fraction of a milliwatt can change the laser output of such a device by a factor of a hundred, thereby enabling a range of optical switching and data encoding applications.

  3. Wavelength-stepped, actively mode-locked fiber laser based on wavelength-division-multiplexed optical delay lines

    Science.gov (United States)

    Lee, Eunjoo; Kim, Byoung Yoon

    2017-12-01

    We propose a new scheme for an actively mode-locked wavelength-swept fiber laser that produces a train of discretely wavelength-stepped pulses from a short fiber cavity. Pulses with different wavelengths are split and combined by standard wavelength division multiplexers with fiber delay lines. As a proof of concept, we demonstrate a laser using an erbium doped fiber amplifier and commercially available wavelength-division multiplexers with wavelength spacing of 0.8 nm. The results show simultaneous mode-locking at three different wavelengths. Laser output parameters in time domain, optical and radio frequency spectral domain, and the noise characteristics are presented. Suggestions for the improved design are discussed.

  4. Impact of multiple sub-melt laser scans on the activation and diffusion of shallow Boron junctions

    DEFF Research Database (Denmark)

    Rosseel, E.; Vandervorst, W.; Clarysse, T.

    2008-01-01

    , careful process optimization is required. While macroscopic variations can easily be addressed using the proper spatial power compensation it is more difficult to completely eliminate the micro scale non-uniformity which is intimately linked to the laser beam profile, the amount of overlaps and the scan...... pitch. In this work, we will present micro scale sheet resistance uniformity measurements for shallow 0.5 keV B junctions and zoom in on the underlying effect of multiple subsequent laser scans. A variety of characterization techniques are used to extract the relevant junction parameters and the role...... of different implantation and anneal parameters will be explored. It turns out that the observed sheet resistance decrease with increasing number of laser scans is caused on one hand by a temperature dependent increase of the activation level, and on the other hand, by a non-negligible temperature...

  5. The Role of Social Media in Societal Change: Cases in Finland of Fifth Estate Activity on Facebook

    Directory of Open Access Journals (Sweden)

    Niina Sormanen

    2015-11-01

    Full Text Available The Internet can be used to reconfigure access to information and people in ways that can support networked individuals and enhance their relative communicative power vis-à-vis other individuals and institutions, such as by supporting collective action, sourcing of information, and whistle blowing. The societal and political significance of the Internet is a matter of academic debate, with some studies suggesting a powerful role in creating a “Fifth Estate,” and other studies challenging such claims. Research on this issue has not yet comprehensively focused on social network sites and those operating in a very liberal-democratic context. Based on an embedded case study of Facebook use in Finland, this study focuses on the uses of social media in building communicative power, such as in capacity to foster social movements in ways that conform to conceptions of the Internet’s Fifth Estate. The case study combines qualitative and quantitative methods to examine a sample of 2,300 Facebook pages and their online and offline activities and impact qualities. The results located 27 pages that reached a threshold we established for identifying online social movements with the potential for enhancing their communicative power, with a small minority of four cases appearing to have actualized communicative power. These findings not only reinforce the potential of Fifth Estate activity on social media but also underline the challenges of societal change in this predominantly entertainment-oriented social context. In addition, the study showcases the intertwined process of online and offline attributes affecting societal influence of online social movements.

  6. Laser-induced activation of regeneration processes in spine disc cartilage

    Science.gov (United States)

    Sobol, Emil N.; Vorobjeva, Natalia N.; Sviridov, Alexander P.; Omelchenko, Alexander I.; Baskov, Andrey V.; Shekhter, Anatoliy B.; Baskov, Vladimir A.; Feldchtein, Felix I.; Kamensky, Vladislav A.; Kuranov, Roman V.

    2000-05-01

    The effect of laser radiation on the regeneration processes in spine disk cartilage has been studied in-vivo. We used rabbits as a model and a Holmium (2.09 micrometer) and an Erbium fiber (1.56 micrometer) lasers for irradiation the discs which were preliminary opened to remove annulus fibrosus and the nucleus pulposus of the intervertebral disc. The irradiated zone has been examined using an optical coherent tomography in one month after the operation and conventional histological technique in two months after the laser operation. It has been shown that laser radiation promotes the growth of the new cartilaginous tissue of fibrous and hyaline types.

  7. Laser Range Profiling for Active Protection System Target Classification and Aim-Point Selection

    National Research Council Canada - National Science Library

    Jones, Michael

    2004-01-01

    .... The attractiveness of smaller, faster interceptors precipitated the investigation of a laser radar sensor augmentation for CIAPS that could quickly resolve the range profile of an incoming projectile...

  8. Protein Dynamics in Organic Media at Varying Water Activity Studied by Molecular Dynamics Simulation

    DEFF Research Database (Denmark)

    Wedberg, Nils Hejle Rasmus Ingemar; Abildskov, Jens; Peters, Günther H.J.

    2012-01-01

    In nonaqueous enzymology, control of enzyme hydration is commonly approached by fixing the thermodynamic water activity of the medium. In this work, we present a strategy for evaluating the water activity in molecular dynamics simulations of proteins in water/organic solvent mixtures. The method...... relies on determining the water content of the bulk phase and uses a combination of Kirkwood−Buff theory and free energy calculations to determine corresponding activity coefficients. We apply the method in a molecular dynamics study of Candida antarctica lipase B in pure water and the organic solvents...

  9. Microorganisms in cryopreserved semen and culture media used in the in vitro production (IVP) of bovine embryos identified by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS).

    Science.gov (United States)

    Zampieri, Dávila; Santos, Vanessa G; Braga, Patrícia A C; Ferreira, Christina R; Ballottin, Daniela; Tasic, Ljubica; Basso, Andréa C; Sanches, Bruno V; Pontes, José H F; da Silva, Bárbara Pereira; Garboggini, Fabiana Fantinatti; Eberlin, Marcos N; Tata, Alessandra

    2013-09-01

    Commercial cattle breeders produce their own herd offspring for the dairy and beef market using artificial insemination. The procedure involves sanitary risks associated with the collection and commercialization of the germplasm, and the in vitro production and transfer of the bovine embryos must be monitored by strict health surveillance. To avoid the spreading of infectious diseases, one must rely on using controlled and monitored germplasm, media, and reagents that are guaranteed free of pathogens. In this article, we investigated the use of a new mass spectrometric approach for fast and accurate identification of bacteria and fungi in bovine semen and in culture media employed in the embryo in vitro production process. The microorganisms isolated from samples obtained in a commercial bovine embryo IVP setting were identified in a few minutes by their conserved peptide/protein profile, obtained applying matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), matched against a commercial database. The successful microorganisms MS identification has been confirmed by DNA amplification and sequencing. Therefore, the MS technique seems to offer a powerful tool for rapid and accurate microorganism identification in semen and culture media samples. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Microwave-Assisted Synthesis of Bio-Active Heterocycles and Fine Chemicals in Aqueous Media

    Science.gov (United States)

    Human health, especially in the aging population, mostly depends on various medicines, and researchers are combating against emerging diseases by new drug discovery. Heterocyclic compounds hold a special place among pharmaceutically active natural products as well as synthetic co...

  11. SERS-active Ag, Au and Ag–Au alloy nanoparticles obtained by laser ablation in liquids for sensing methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Olea-Mejía, Oscar, E-mail: oleaoscar@yahoo.com.mx [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Universidad Autónoma del Estado de México, km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50200, México (Mexico); Fernández-Mondragón, Mariana; Rodríguez-de la Concha, Gabriela [Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Universidad Autónoma del Estado de México, km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50200, México (Mexico); Camacho-López, Marco [Laboratorio de Investigación y Desarrollo de Materiales Avanzados, Universidad Autónoma del Estado de México, Km 14.5 Carretera Toluca-Atlacomulco, San Cayetano 50925, México (Mexico)

    2015-09-01

    Highlights: • We synthesized Ag/Au nanoparticles by laser ablation in liquids. • We characterized such particles by UV–vis, TEM and EDS/STEM. • The SERS effect was studied for the obtained nanoparticles. • Pure silver nanoparticles showed the highest SERS signals. • We can sense methylene blue at a concentration of 10{sup −10} mole/L. - Abstract: We have synthesized Ag–Au nanoparticles by laser ablation in liquids using five different targets: 100% Ag, 80%Ag/20%Au, 50%Ag/50%Au, 20%Ag/80%Au and 100% Au (weight percentages). We used ethanol and methylene blue solutions in ethanol as the liquid media. The nanoparticles were mostly spherical with diameters 15, 19, 18, 23 and 11 nm, respectively. When alloyed targets were used, the resulting nanoparticles were completely alloyed forming solid solutions as evidenced by UV–vis Spectroscopy and Scanning Transmission Electron Microscopy. The obtained nanoparticles were employed to study the SERS effect of the methylene blue molecule. All the samples showed good SERS activity, however the ones composed of pure silver showed the greatest Raman signal enhancement. Finally, pure Ag nanoparticles were used for sensing methylene blue at different concentrations. While almost no signal can be discerned from the Raman spectrum when no particles are used at a concentration of methylene blue of 1 × 10{sup −2} M (∼3000 ppm), when Ag nanoparticles are used one can observe the characteristic peak of the molecule at concentrations as low as 1 × 10{sup −10} M (∼3 × 10{sup −5} ppm)

  12. Influence of Laser Activated Irrigation with Erbium Lasers on Bond Strength of Inidividually Formed Fiber Reinforced Composite Posts to Root Canal Dentin

    Directory of Open Access Journals (Sweden)

    Ivana Miletić

    2016-01-01

    Full Text Available Objective: The aim of this in vitro study was to investigate the effect of laser activated irrigation (LAI using two erbium lasers on bond strength of individually formed fiber-reinforced composite (FRC posts to root canal dentin. Materials and methods: Twenty-seven single-rooted human teeth were endodontically treated and after post space preparation divided into three groups (n=9 per group, according to the pre-treatment of post space preparation: 1 Conventional syringe irrigation (CSI and saline; 2 Er.YAG photon-induced photoacoustic streaming (PIPS technique and saline; 3 Er,Cr:YSGG activated irrigation with RFT2 tip. Two specimens from each group were used for SEM analysis. The remaining specimens (n=7 per group received individually formed FRC post, everStick POST, luted with self-adhesive cement, G-CEM LinkAce. After cementation, the roots were perpendicularly sectioned into 1 mm thin sections and a push-out test was carried out (0.5 mm/min. The data were calculated as megapascals and were log transformed and statistically analysed using one-way ANOVA at the level of significance set at 5%. Results: In the control group, the smear layer was still present. In the Er:YAG group, the smear layer was removed. In the Er,Cr:YSGG group, the smear layer was partially removed. The Er,Cr:YSGG group achieved the highest bond strength values, followed by the control group and then the Er:YAG group, but no statistically significant difference was found in bond strength values in the tested group of post space pretreatment (p=0.564. Conclusions: LAI using two erbium lasers, with PIPS or RFT2 tip, did not affect the bond strength of individually formed FRC posts to root canal dentin.

  13. Short and long time effects of low temperature Plasma Activated Media on 3D multicellular tumor spheroids

    Science.gov (United States)

    Judée, Florian; Fongia, Céline; Ducommun, Bernard; Yousfi, Mohammed; Lobjois, Valérie; Merbahi, Nofel

    2016-02-01

    This work investigates the regionalized antiproliferative effects of plasma-activated medium (PAM) on colon adenocarcinoma multicellular tumor spheroid (MCTS), a model that mimics 3D organization and regionalization of a microtumor region. PAM was generated by dielectric barrier plasma jet setup crossed by helium carrier gas. MCTS were transferred in PAM at various times after plasma exposure up to 48 hours and effect on MCTS growth and DNA damage were evaluated. We report the impact of plasma exposure duration and delay before transfer on MCTS growth and DNA damage. Local accumulation of DNA damage revealed by histone H2AX phosphorylation is observed on outermost layers and is dependent on plasma exposure. DNA damage is completely reverted by catalase addition indicating that H2O2 plays major role in observed genotoxic effect while growth inhibitory effect is maintained suggesting that it is due to others reactive species. SOD and D-mannitol scavengers also reduced DNA damage by 30% indicating that and OH* are involved in H2O2 formation. Finally, PAM is able to retain its cytotoxic and genotoxic activity upon storage at +4 °C or -80 °C. These results suggest that plasma activated media may be a promising new antitumor strategy for colorectal cancer tumors.

  14. Concerning at distance: digital activism and social media empowerment between Latin-American migrants in Spain

    Directory of Open Access Journals (Sweden)

    David RAMIREZ PLASCENCIA

    2016-12-01

    Full Text Available This paper focuses on developing some important points about the use of social platforms in the life of Latin-Americans in Spain, particularly Mexican, Colombian and Venezuelan migrants. It shows the outcomes of data collected on closed groups in Facebook. The main topic centers on how social networks catalyze the spread of political engagement and public activism in between migrants concerning public matters in their homelands. Final outcomes will show that there is a clear inclination in using social platforms to discuss, organize and participate in public activism focused on resolving homeland problems. In this context, these virtual spaces serve as a link to stay in touch with their communities in Latin-America. Migrants are not only using social networks to make new relations in their new context but to ensure not to lose the connection with their friends and relatives, and of course, participate in social and political activism.

  15. Single Atomic Iron Catalysts for Oxygen Reduction in Acidic Media: Particle Size Control and Thermal Activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hanguang [Department; Hwang, Sooyeon [Center; Wang, Maoyu [School; Feng, Zhenxing [School; Karakalos, Stavros [Department; Luo, Langli [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Qiao, Zhi [Department; Xie, Xiaohong [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wang, Chongmin [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Su, Dong [Center; Shao, Yuyan [Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Wu, Gang [Department

    2017-09-26

    To significantly reduce the cost of proton exchange membrane (PEM) fuel cells, current Pt must be replaced by platinum-metal-group (PGM)-free catalysts for the oxygen reduction reaction (ORR) in acid. We report here a new class of high-performance atomic iron dispersed carbon catalysts through controlled chemical doping of iron ions into zinc-zeolitic imidazolate framework (ZIF), a type of metal-organic framework (MOF). The novel synthetic chemistry enables accurate size control of Fe-doped ZIF catalyst particles with a wide range from 20 to 1000 nm without changing chemical properties, which provides a great opportunity to increase the density of active sites that is determined by the particle size. We elucidated the active site formation mechanism by correlating the chemical and structural changes with thermal activation process for the conversion from Fe-N4 complex containing hydrocarbon networks in ZIF to highly active FeNx sites embedded into carbon. A temperature of 800oC was identified as the critical point to start forming pyridinic nitrogen doping at the edge of the graphitized carbon planes. Further increasing heating temperature to 1100oC leads to increase of graphitic nitrogen, generating possible synergistic effect with FeNx sites to promote ORR activity. The best performing catalyst, which has well-defined particle size around 50 nm and abundance of atomic FeNx sites embedded into carbon structures, achieve a new performance milestone for the ORR in acid including a half-wave potential of 0.85 V vs RHE and only 20 mV loss after 10,000 cycles in O2 saturated H2SO4 electrolyte. The new class PGM-free catalyst with approaching activity to Pt holds great promise for future PEM fuel cells.

  16. Is Political Activism on Social Media an initiator of Psychological Stress?

    Science.gov (United States)

    Hisam, Aliya; Safoor, Iqra; Khurshid, Nawal; Aslam, Aakash; Zaid, Farhan; Muzaffar, Ayesha

    2017-01-01

    To find out the association of psychological stress with political activism on social networking sites (SNS) in adults. To find association of psychological stress and political activism with age, gender and occupational status. A descriptive cross-sectional study of 8 months (Aug 2014 to March 2015) was conducted on young adults between age group of 20-40 years of different universities of Rawalpindi, Pakistan. Closed ended standardized questionnaires (i.e. Cohen Perceived Stress-10) were distributed via non-probability convenient sampling among a total sample size of 237. Sample size was calculated using WHO sample size calculator and data was analyzed in STATA version 12. The mean age of participants was 21.06±1.425 years. Out of the 237 participants, 150 (63.3%) were males and 87 (36.7%) females. Regarding their occupation, 13 (51.9%) were military cadets, 8 (3.4%) were consultant, 47 (19.8%) medical officer, 3 (1.3%) PG students and 56 (23.6%) MBBS students. Significant association of occupation was established with both political activism and psychological stress (p=0.4 and p=0.002 respectively). Among 237 individuals, 91 (38.4%) were stressed out and 146 (61.6%) were not. Among whole sample, political activists on SNS were found to be 23 (9.7%). Out of these 23 individuals who were politically active, 15 (65.2%) were stressed out and 8 (34.7%) were not. A significant association between stress and political activism was established (p=0.005). Political activism via social networking sites is playing significant role on adult person's mental health in terms of stress among different occupation.

  17. Production of active lysozyme films by matrix assisted pulsed laser evaporation at 355 nm

    DEFF Research Database (Denmark)

    Purice, Andreea; Schou, Jørgen; Kingshott, P.

    2007-01-01

    Thin lysozyme films have been produced in a dry environment by MAPLE (matrix assisted pulsed laser evaporation) from a water ice matrix irradiated by laser light at 355 nm above the absorption threshold of the protein. A significant part of the lysozyme molecules are transferred to the film without...

  18. Validation of a Portuguese version of the health-related quality of life measure for active chronic otitis media (COMQ-12).

    Science.gov (United States)

    Fonseca, Anna Carolina Oliveira; Ramos, Pedro; Balsalobre, Fernando A; Freitas, Edson L; Phillips, John S; Yung, Matthew W; Bento, Ricardo F

    2017-09-01

    Measuring the impact on quality of life, especially after the beginning of the treatment, is becoming increasingly important in healthcare. The aim of this study was to translate the Chronic Otitis Media Questionnaire-12 (COMQ-12) into Portuguese language and validate this version in a group of patients with chronic otitis media. The Portuguese version of COMQ-12 was obtained by translation and back translation. Portuguese speaking patients with a history of active chronic otitis media were asked to complete the COMQ-12 Portuguese version. Cronbach's α coefficient was calculated for an estimation of the internal consistency of the questionnaire. A total of 100 patients were included in the study; 49 women and 51 men, with a mean age of 39 years (range 12-77 years, median 40 years). The average COMQ-12 score was 29, out of a maximum score of 60. Cronbach's α result for the Portuguese version of the COMQ-12 was 0.85, indicating a high internal consistency. The participants presented with different forms of chronic otitis media, and almost all domains of the COMQ-12 questionnaire were able to differentiate between patients with healed chronic otitis media and patients with cholesteatoma or wet tympanic membrane perforation. Showing that patients with healed chronic otitis media have a better quality of life, measured by the COMQ-12, is a first step to guarantee the questionnaire's validity. The next step will consist on routinely using the questionnaire in patients undergoing surgery for chronic otitis media in order to evaluate their quality of life after treatment. The COMQ-12 Portuguese version showed high reliability, and may be used as an assessment of quality of life in patients with chronic otitis media. Copyright © 2017 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. All rights reserved.

  19. Low-level laser therapy activates NF-kB via generation of reactive oxygen species in mouse embryonic fibroblasts.

    Directory of Open Access Journals (Sweden)

    Aaron C-H Chen

    Full Text Available Despite over forty years of investigation on low-level light therapy (LLLT, the fundamental mechanisms underlying photobiomodulation at a cellular level remain unclear.In this study, we isolated murine embryonic fibroblasts (MEF from transgenic NF-kB luciferase reporter mice and studied their response to 810 nm laser radiation. Significant activation of NF-kB was observed at fluences higher than 0.003 J/cm(2 and was confirmed by Western blot analysis. NF-kB was activated earlier (1 hour by LLLT compared to conventional lipopolysaccharide treatment. We also observed that LLLT induced intracellular reactive oxygen species (ROS production similar to mitochondrial inhibitors, such as antimycin A, rotenone and paraquat. Furthermore, we observed similar NF-kB activation with these mitochondrial inhibitors. These results, together with inhibition of laser induced NF-kB activation by antioxidants, suggests that ROS play an important role in the laser induced NF-kB signaling pathways. However, LLLT, unlike mitochondrial inhibitors, induced increased cellular ATP levels, which indicates that LLLT also upregulates mitochondrial respiration.We conclude that LLLT not only enhances mitochondrial respiration, but also activates the redox-sensitive NFkB signaling via generation of ROS. Expression of anti-apoptosis and pro-survival genes responsive to NFkB could explain many clinical effects of LLLT.

  20. A simulation environment for assisting system design of coherent laser doppler wind sensor for active wind turbine pitch control

    Science.gov (United States)

    Shinohara, Leilei; Pham Tran, Tuan Anh; Beuth, Thorsten; Umesh Babu, Harsha; Heussner, Nico; Bogatscher, Siegwart; Danilova, Svetlana; Stork, Wilhelm

    2013-05-01

    In order to assist a system design of laser coherent Doppler wind sensor for active pitch control of wind turbine systems (WTS), we developed a numerical simulation environment for modeling and simulation of the sensor system. In this paper we present this simulation concept. In previous works, we have shown the general idea and the possibility of using a low cost coherent laser Doppler wind sensing system for an active pitch control of WTS in order to achieve a reduced mechanical stress, increase the WTS lifetime and therefore reduce the electricity price from wind energy. Such a system is based on a 1.55μm Continuous-Wave (CW) laser plus an erbium-doped fiber amplifier (EDFA) with an output power of 1W. Within this system, an optical coherent detection method is chosen for the Doppler frequency measurement in megahertz range. A comparatively low cost short coherent length laser with a fiber delay line is used for achieving a multiple range measurement. In this paper, we show the current results on the improvement of our simulation by applying a Monte Carlo random generation method for positioning the random particles in atmosphere and extend the simulation to the entire beam penetrated space by introducing a cylindrical co-ordinate concept and meshing the entire volume into small elements in order to achieve a faster calculation and gain more realistic simulation result. In addition, by applying different atmospheric parameters, such as particle sizes and distributions, we can simulate different weather and wind situations.

  1. Ultra-Shallow P+/N Junction Formation in Si Using Low Temperature Solid Phase Epitaxy Assisted with Laser Activation

    International Nuclear Information System (INIS)

    Hara, Shuhei; Tanaka, Yuki; Fukaya, Takumi; Matsumoto, Satoru; Suzuki, Toshiharu; Fuse, Genshu; Kudo, Toshio; Sakuragi, Susumu

    2008-01-01

    A combination of Ge pre-amorphization implantation (Ge-PAI), low-energy B implantation and laser annealing is a promising method to form highly-activated, abrupt and ultra-shallow junctions (USJ). In our previous report of IIT 2006, we succeeded in forming pn junctions less than 10 nm using non-melt double-pulsed green laser. However, a large leakage current under reverse bias was observed consequently due to residual defects in the implanted layer. In this study, a method to form USJ is proposed: a combination of low-temperature solid phase epitaxy and non-melt laser irradiation for B activation. Ge pre-amorphization implantation was performed at energy of 6 keV with a dose of 3x10 14 /cm 2 . Then B implantation was performed at energy of 0.2 keV with a dose of 1.2x10 15 /cm 2 . Samples were annealed at 400 deg. C for 10 h in nitrogen atmosphere. Subsequently, non-melt laser irradiation was performed at energy of 690 mJ/cm 2 and pulse duration of 100 ns with intervals of 300 ns. As a result, USJ around 10 nm with better crystallinity was successfully formed. And the leakage current of pn diodes was reduced significantly. Moreover, it is proven from secondary ion mass spectroscopy (SIMS) analysis that transient enhanced diffusion (TED) of B is specifically suppressed.

  2. Enhancing Learning with the Social Media: Student Teachers' Perceptions on Twitter in a Debate Activity

    Science.gov (United States)

    Tur, Gemma; Marín, Victoria I.

    2015-01-01

    This paper presents research focused on the educational experience of students using the microblogging platform Twitter for debate activities in three groups in different teacher education programmes at the University of the Balearic Islands, Spain. The implementation of this technology-based task in a face-to-face class was introduced as an…

  3. Integrating Active Learning, Critical Thinking and Multicultural Education in Teaching Media Ethics across the Curriculum.

    Science.gov (United States)

    Brislin, Tom

    This paper presents four teaching strategies, grounded in pedagogical theory, to encourage an active, challenging, creative, and meaningful experience for journalism and mass communication students grappling with moral issues, and developing higher order thinking in ethical decision-making processes. Strategies emphasizing critical thinking and…

  4. Constructing Media Artifacts in a Social Constructivist Environment to Enhance Students' Environmental Awareness and Activism

    Science.gov (United States)

    Karahan, Engin; Roehrig, Gillian

    2015-02-01

    Current science education reforms and policy documents highlight the importance of environmental awareness and perceived need for activism. As "environmental problems are socially constructed in terms of their conceptualized effects on individuals, groups, other living things and systems research based on constructivist principles provides not only a coherent framework in which to theorize about learning, but also a context for understanding socially constructed issues" (Palmer and Suggate in Res Pap Educ 19(2), 2004, p. 208). This research study investigated the impacts of the learning processes structured based on the theories of constructionism and social constructivism on students' environmental awareness and perceived need for activism. Students constructed multimedia artifacts expressing their knowledge, attitudes, awareness, and activism about environmental issues through a constructionist design process. In addition, a social networking site was designed and used to promote social interaction among students. Twenty-two high school environmental science students participated in this study. A convergent mixed methods design was implemented to allow for the triangulation of methods by directly comparing and contrasting quantitative results with qualitative findings for corroboration and validation purposes. Using a mixed method approach, quantitative findings are supported with qualitative data (student video projects, writing prompts, blog entries, video projects of the students, observational field notes, and reflective journals) including spontaneous responses in both synchronous and asynchronous conversations on the social network to provide a better understanding of the change in students' environmental awareness and perceived need for activism. The findings of the study indicated that students' environmental awareness and perceived need for activism were improved at different scales (personal, community, global) throughout the constructionist and social

  5. Understanding Social Media Logic

    Directory of Open Access Journals (Sweden)

    José van Dijck

    2013-08-01

    Full Text Available Over the past decade, social media platforms have penetrated deeply into the mech­anics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media logic—the norms, strategies, mechanisms, and economies—underpin­ning its dynamics. This logic will be considered in light of what has been identified as mass me­dia logic, which has helped spread the media's powerful discourse outside its institutional boundaries. Theorizing social media logic, we identify four grounding principles—programmabil­ity, popularity, connectivity, and datafication—and argue that these principles become increas­ingly entangled with mass media logic. The logic of social media, rooted in these grounding principles and strategies, is gradually invading all areas of public life. Besides print news and broadcasting, it also affects law and order, social activism, politics, and so forth. Therefore, its sustaining logic and widespread dissemination deserve to be scrutinized in detail in order to better understand its impact in various domains. Concentrating on the tactics and strategies at work in social media logic, we reassess the constellation of power relationships in which social practices unfold, raising questions such as: How does social media logic modify or enhance ex­isting mass media logic? And how is this new media logic exported beyond the boundaries of (social or mass media proper? The underlying principles, tactics, and strategies may be relat­ively simple to identify, but it is much harder to map the complex connections between plat­forms that distribute this logic: users that employ them, technologies that

  6. Media education.

    Science.gov (United States)

    Strasburger, Victor C

    2010-11-01

    The American Academy of Pediatrics recognizes that exposure to mass media (eg, television, movies, video and computer games, the Internet, music lyrics and videos, newspapers, magazines, books, advertising) presents health risks for children and adolescents but can provide benefits as well. Media education has the potential to reduce the harmful effects of media and accentuate the positive effects. By understanding and supporting media education, pediatricians can play an important role in reducing harmful effects of media on children and adolescents.

  7. A curcumin activated carboxymethyl cellulose-montmorillonite clay nanocomposite having enhanced curcumin release in aqueous media.

    Science.gov (United States)

    Madusanka, Nadeesh; de Silva, K M Nalin; Amaratunga, Gehan

    2015-12-10

    A novel curcumin activated carboxymethylcellulose-montmorillonite nanocomposite is reported. A superabsorbent biopolymer; carboxymethyl cellulose (CMC) was used as an emulsifier for curcumin which is a turmeric derived water insoluble polyphenolic compound with antibacterial/anti-cancer properties. Montmorillonite (MMT) nanoclay was incorporated in the formulation as a matrix material which also plays a role in release kinetics. It was observed that water solubility of curcumin in the nanocomposite has significantly increased (60% release within 2h and 30 min in distilled water at pH 5.4) compared to pure curcumin. The prepared curcumin activated carboxymethylcellulose-montmorillonite nanocomposite is suitable as a curcumin carrier having enhanced release and structural properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Concerning at distance: digital activism and social media empowerment between Latin-American migrants in Spain

    OpenAIRE

    Ramírez Plascencia, David

    2016-01-01

    This paper focuses on developing some important points about the use of social platforms in the life of Latin-Americans in Spain, particularly Mexican, Colombian and Venezuelan migrants. It shows the outcomes of data collected on closed groups in Facebook. The main topic centers on how social networks catalyze the spread of political engagement and public activism in between migrants concerning public matters in their homelands. Final outcomes will show that there is a clear inclination in us...

  9. The energetic conditions determining the active dissolution of carbon steel during electrocoagulation in sulfate media

    International Nuclear Information System (INIS)

    Gerónimo-López, Carlos; Vazquez-Arenas, Jorge; Picquart, Michel; González, Ignacio

    2014-01-01

    This study aims to investigate the active dissolution of carbon steel under rotating conditions, necessary for continuous dosing of metal cation in electrocoagulation. A reaction mechanism is proposed for its dissolution in 0.1, 0.3 and 0.5 M Na 2 SO 4 , using electrochemical and chemical techniques (Raman, SEM). A continuous dissolution region was obtained from the potentiodynamic study, as a result of the competition between the rate of electrochemical reactions and the rate at which energetic conditions are imposed on the electrode. On the other hand, the dissolution of carbon steel underwent active, transition and passivation regions in potentiostatic and galvanostatic techniques, which respectively shifted to higher current densities and more positive potentials as the electrolyte concentration (Na 2 SO 4 ) was increased. In general, the increase of Na 2 SO 4 concentration promotes the iron dissolution and tightens the active region. The results revealed that the Na 2 SO 4 concentration, the Fe(II)/Fe(III) interface concentration, and the time of perturbation influence the occurrence and evolution of the Green Rust Sulphate (NaFe 6 II Fe 3 III (OH) 18 (SO 4 ) 2 ) intermediary, a precursor which hinders electrocoagulation through passive film formation. Scanning Electronic Microscopy and Raman spectroscopy showed that in the active dissolution region, the films grown potentiostatically are porous and contain α-FeOOH, δ-FeOOH, and Fe 3 O 4 as the dominant species. In the transition region, these films become less porous and include α-FeOOH, Fe 3 O 4 , α-Fe 2 O 3 , γ-Fe 2 O 3 , while γ-FeOOH was identified in the passive region

  10. Morphology-dependent activity of Pt nanocatalysts for ethanol oxidation in acidic media: Nanowires versus nanoparticles

    International Nuclear Information System (INIS)

    Zhou Weiping; Li Meng; Koenigsmann, Christopher; Ma Chao; Wong, Stanislaus S.; Adzic, Radoslav R.

    2011-01-01

    Highlights: → We demonstrate the morphology effect of Pt catalysts in electrooxidation of ethanol and CO in an acidic solution. → Pt nanowires and nanoparticles were used as catalysts. → Pt nanowires display a higher catalytic activity by a factor of at least two relative to those nanoparticles for ethanol oxidation. → The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. - Abstract: The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection-absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO 2 -to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail.

  11. Morphology-dependent activity of Pt nanocatalysts for ethanol oxidation in acidic media: Nanowires versus nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Weiping, E-mail: wpzhou@bnl.gov [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Li Meng [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States); Koenigsmann, Christopher [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States); Ma Chao [Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory, Building 480, Upton, NY 11973 (United States); Wong, Stanislaus S. [Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794 (United States); Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory, Building 480, Upton, NY 11973 (United States); Adzic, Radoslav R. [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2011-11-30

    Highlights: > We demonstrate the morphology effect of Pt catalysts in electrooxidation of ethanol and CO in an acidic solution. > Pt nanowires and nanoparticles were used as catalysts. > Pt nanowires display a higher catalytic activity by a factor of at least two relative to those nanoparticles for ethanol oxidation. > The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. - Abstract: The morphology of nanostructured Pt catalysts is known to affect significantly the kinetics of various reactions. Herein, we report on a pronounced morphology effect in the electrooxidation of ethanol and carbon monoxide (CO) on Pt nanowires and nanoparticles in an acidic solution. The high resolution transmission electron microscopy analysis showed the inherent morphology difference between these two nanostructured catalysts. Voltammetric and chronoamperometric studies of the ethanol electrooxidation revealed that these nanowires had a higher catalytic activity by a factor of two relative to these nanoparticles. The rate for CO monolayer oxidation exhibits similar morphology-dependent behavior with a markedly enhanced rate on the Pt nanowires. In situ infrared reflection-absorption spectroscopy measurements revealed a different trend for chemisorbed CO formation and CO{sub 2}-to-acetic acid reaction product ratios on these two nanostructures. The morphology-induced change in catalytic activity and selectivity in ethanol electrocatalysis is discussed in detail.

  12. Microscopic analysis of the optoelectronic properties of semiconductor gain media for laser applications; Mikroskopische Analyse optoelektronischer Eigenschaften von Halbleiterverstaerkungsmedien fuer Laseranwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Bueckers, Christina

    2010-12-03

    A microscopic many-particle theory is applied to model a wide range of semiconductor laser gain materials. The fundamental understanding of the gain medium and the underlying carrier interaction processes allow for the quantitative prediction of the optoelectronic properties governing the laser performance. Detailed theory-experiment-comparisons are shown for a variety of structures demonstrating the application capabilities of the theoretical approach. The microscopically calculated material properties, in particular absorption, optical gain, luminescence and the intrinsic carrier losses due to radiative and Auger-recombination, constitute the critical input to analyse and design laser structures. On this basis, important system features such as laser wavelength or threshold behaviour become predictable. However, the theory is also used in a diagnostic fashion, e.g. to extract otherwise poorly known structural parameter. Thus, novel concepts for the optimisation of laser designs may be developed with regard to the requirements of specific applications. Moreover, the approach allows for the systematic exploration and assessment of completely novel material systems and their application potential. (orig.)

  13. Healing activity of laser InGaAlP (660nm in rats Atividade cicatrizante do laser AlGaInP (660nm em ratos

    Directory of Open Access Journals (Sweden)

    Kelly Cristina Borges Tacon

    2011-10-01

    Full Text Available PURPOSE: To evaluate the effect the healing activity of diode laser Indium Gallium Aluminum Phosphorus (InGaAlP ë660nm on healing of surgical wounds in rats. METHODS: Fifty-four female Wistar rats were used, divided into three groups (n=18 and subdivided into three subgroups (n=6 to be studied in 5, 10 and 15th days after surgical procedures. The wound was induced in the dorsal-cervical using punch. The lesions were irradiated on alternate days with InGaAlP laser, the energy densities of 3J/cm² (L3 or 6J/cm² (L6. The control group received no irradiation. At 5, 10 and 15th days after surgery the animals were euthanized and the repair area was removed and histological sections were stained with hematoxylin-eosin and picrossírius. We evaluated macroscopic and histological lesions in the times cited, as well as morphometric analysis of angiogenesis and collagen content. RESULTS: The wound healing activity InGaAlP laser was evidenced by increased angiogenesis group L3 and L6 in relation to control group (CG at the 5th day (p=0.0001 and decreased polymorphonuclear infiltrate and hemorrhage (p=0.045 and p=0.07 respectively in the groups L3 and L6 in relation to control group (GC. On the 10 and 15th days was also observed in groups treated with laser L3 and L6 stimulation was pronounced fibroplasia (p=0.0003 and p=0.034 respectively when compared with the control group (CG. CONCLUSION: The InGaAlP laser acted positively on the healing of skin wounds in rats.OBJETIVO: Avaliar a atividade cicatrizante do laser diodo Alumínio Gálio Índio Fósforo (AlGaInP, ë660nm em feridas cutâneas induzida em ratos. MÉTODOS: Foram utilizados 54 ratos Wistar, fêmeas, divididos em três grupos (n=18 e subdivididos em três subgrupos (n=6 animais para serem estudados no 5, 10 e 15º dias após o procedimento cirúrgico. A ferida foi induzida em região dorso-cervical utilizando punch. As lesões foram irradiadas em dias alternados com laser AlGaInP, nas

  14. The effect of excimer laser keratectomy on corneal glutathione peroxidase activities and aqueous humor selenium levels in rabbits.

    Science.gov (United States)

    Yis, Ozgür; Bilgihan, Ayşe; Bilgihan, Kamil; Yis, Nilgün Safak; Hasanreisoğlu, Berati

    2002-06-01

    The formation of free oxygen radicals has been demonstrated in the corneal tissue after 193 nm laser irradiation. Cornea has several defense mechanisms that protect against oxidative damage. One of them, glutathione peroxidase (GPx), catalyzes the destruction of hydrogen peroxide and lipid hydroperoxide. Selenium is a trace element which is incorporated into the selenoenzyme GPx. In the present study, the effect of excimer laser keratectomy on corneal GPx activities and aqueous humor selenium concentrations in rabbits was evaluated. Animals were divided into five groups, and all groups were compared: controls (group 1), after epithelial scraping (group 2), transepithelial photorefractive keratectomy(PRK; group 3), superficial traditional PRK (50 microm; group 4) and deep traditional PRK (100 microm; group 5). Corneal GPx activities were measured by a modification of the coupled assay procedure. Aqueous humor selenium concentrations were determined using hydride generation atomic absorption spectrometry. Corneal GPx activities were significantly lower only in group 5 ( P<0.05), and the selenium concentration in the aqueous humor did not change in any group. Deep corneal photoablation inhibits GPx enzyme activities in the cornea. Therefore, antioxidants may be useful in reducing free radical-mediated complications after excimer laser corneal photoablation.

  15. Molecular mechanism of carbon nanotube to activate Subtilisin Carlsberg in polar and non-polar organic media

    Science.gov (United States)

    Zhang, Liyun; Li, Yuzhi; Yuan, Yuan; Jiang, Yuanyuan; Guo, Yanzhi; Li, Menglong; Pu, Xuemei

    2016-11-01

    In the work, we mainly used molecular dynamics (MD) simulation and protein structure network (PSN) to study subtilisin Carlsberg (SC) immobilized onto carbon nanotube (CNT) in water, acetonitrile and heptane solvents, in order to explore activation mechanism of enzymes in non-aqueous media. The result indicates that the affinity of SC with CNT follows the decreasing order of water > acetonitrile > heptane. The overall structure of SC and the catalytic triad display strong robustness to the change of environments, responsible for the activity retaining. However, the distances between two β-strands of substrate-binding pocket are significantly expanded by the immobilization in the increasing order of water communication paths to the substrate-binding pocket, leading to its larger change than the free-enzymes. Interestingly, the increase in the number of the pathways upon immobilization is not dependent on the absorbed extent but the desorbed one, indicating significant role of shifting process of experimental operations in influencing the functional region. In addition, some conserved and important hot-residues in the paths are identified, providing molecular information for functional modification.

  16. Broad band exciplex dye lasers

    International Nuclear Information System (INIS)

    Dienes, A.; Shank, C.V.; Trozzolo, A.M.

    1975-01-01

    The disclosure is concerned with exciplex dye lasers, i.e., lasers in which the emitting species is a complex formed only from a constituent in an electronically excited state. Noting that an exciplex laser, favorable from the standpoint of broad tunability, results from a broad shift in the peak emission wavelength for the exciplex relative to the unreacted species, a desirable class resulting in such broad shift is described. Preferred classes of laser media utilizing specified resonant molecules are set forth. (auth)

  17. Profiling of Cytokines Secreted by Conventional Aqueous Outflow Pathway Endothelial Cells Activated In Vitro and Ex Vivo With Laser Irradiation.

    Science.gov (United States)

    Alvarado, Jorge A; Chau, Phuonglan; Wu, Jianfeng; Juster, Richard; Shifera, Amde Selassie; Geske, Michael

    2015-11-01

    To profile which cytokine genes are differentially expressed (DE) as up- or downregulated by cultured human trabecular meshwork (TMEs) and Schlemm's canal endothelial cells (SCEs) after three experimental treatments consisting of selective laser trabeculoplasty (SLT) irradiation, exposure to media conditioned either by SLT-irradiated TMEs (TME-cm) or by SCEs (SCE-cm). Also, to profile which cytokines are upregulated ex vivo in SLT-irradiated human conventional aqueous outflow pathway (CAOP) tissues. After each treatment, Affymetrix microarray assays were used to detect upregulated and downregulated genes for cytokines and their receptors in TMEs and SCEs. ELISA and protein antibody arrays were used to detect upregulated cytokines secreted in SLT-irradiated CAOP tissues ex vivo. The SLT irradiation upregulated numerous cytokine genes in TMEs, but only a few in SCEs. Exposure to TME- and SCE-cm induced SCEs to upregulate many more cytokine genes than TMEs. Selective laser trabeculoplasty irradiation and exposure to TME-cm downregulated several cytokine genes in TMEs but none in SCEs. Selective laser trabeculoplasty irradiation induced one upregulated and three downregulated cytokine-receptor genes in TMEs but none in SCEs. Exposure to TME-cm induced upregulation of one and downregulation of another receptor gene in TMEs, whereas two unique cytokine-receptor genes were upregulated in SCEs. Cytokine protein expression analysis showed that at least eight cytokines were upregulated in SLT-irradiated human CAOP tissues in situ/ex vivo. This study has helped us identify a cytokine signaling pathway and to consider newly identified mechanisms regulating aqueous outflow that may lay the foundation for the future development of cytokine-based glaucoma therapies.

  18. Introduction to Media.

    Science.gov (United States)

    Riler, Robert

    Designed for senior high school students, this one semester course focuses on four aspects of modern media: television, film, radio, and advertising. Each topic is worked into a weekly lesson plan format that stresses the active involvement of students in the learning process. The course outline contains lists of objectives and media materials…

  19. Building Social Media Connections

    Science.gov (United States)

    Ferriter, William N.; Ramsden, Jason T.; Sheninger, Eric C.

    2012-01-01

    Incorporating social media tools into your professional practices does not have to be intimidating as long as you are willing to tackle five action steps. It is far easier to articulate the strengths--and to imagine the possibilities--of social media spaces as tools for communication and professional development when you are actively using those…

  20. Effects of trajectory exercise using a laser pointer on electromyographic activities of the gluteus maximus and erector spinae during bridging exercises.

    Science.gov (United States)

    Kim, Yu-Ri; Yoo, Won-Gyu

    2016-01-01

    [Purpose] The purpose of this study was to investigate activities of the hip extensors and erector spinae during bridging exercise by using instruments with a laser pointer on the pelvic belt. [Subjects] Twelve subjects (age, 23 to 33 years) with non-specific low back pain volunteered for this study. [Methods] Subjects performed bridging exercises with and without trajectory exercises by using a laser pointer fixed to a pelvic strap. The erector spinae, gluteus maximus and hamstring activities with and without trajectory exercises using a laser pointer were recorded on using electromyography. [Results] Compared to the without laser pointer group, the group that underwent bridging with trajectory exercises using a laser pointer had significantly higher gluteus maximus activity and significantly lower erector spinae activity. Significantly higher gluteus maximus/erector spinae activity ratios were observed when performing trajectory exercises using a laser pointer during bridging exercises. [Conclusion] This result suggests that trajectory exercises using a laser pointer during a bridging exercise would be effective for improving gluteus maximus activity.