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Sample records for negative pi-meson radiation

  1. Secondary production of neutral pi-mesons and the diffuse galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Dermer, C. D.

    1986-01-01

    Isobaric and scaling model predictions of the secondary spectra of neutral pi-mesons produced in proton-proton collisions, at energies between threshold and a few GeV, are compared on the basis of accelerator data and found to show the isobaric model to be superior. This model is accordingly used, in conjuction with a scaling model representation at high energies, in a recalculation of the pi exp (0) gamma-radiation's contribution to the diffuse galactic gamma background; the cosmic ray-induced production of photons (whose energy exceeds 100 MeV) by such radiation occurs at a rate of 1.53 x 10 to the -25 photons/(s-H atom). These results are compared with previous calculations of this process as well as with COS-B observations of the diffuse galactic gamma-radiation.

  2. Secondary production of neutral pi-mesons and the diffuse galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Dermer, C. D.

    1986-01-01

    Isobaric and scaling model predictions of the secondary spectra of neutral pi-mesons produced in proton-proton collisions, at energies between threshold and a few GeV, are compared on the basis of accelerator data and found to show the isobaric model to be superior. This model is accordingly used, in conjuction with a scaling model representation at high energies, in a recalculation of the pi exp (0) gamma-radiation's contribution to the diffuse galactic gamma background; the cosmic ray-induced production of photons (whose energy exceeds 100 MeV) by such radiation occurs at a rate of 1.53 x 10 to the -25 photons/(s-H atom). These results are compared with previous calculations of this process as well as with COS-B observations of the diffuse galactic gamma-radiation.

  3. Response of V79 cells to low doses of X-rays and negative pi-mesons: clonogenic survival and DNA strand breaks.

    PubMed

    Marples, B; Adomat, H; Koch, C J; Skov, K A

    1996-10-01

    Mammalian cells are hypersensitive to very low doses of X-rays (< 0.2 Gy), a response which is followed by increased radioresistance up to 1 Gy. Increased radioresistance is postulated to be a response to DNA damage, possibly single-strand breaks, and it appears to be a characteristic of low linear energy transfer (LET) radiation. Here we demonstrate a correspondence between the extent of the increased radioresistance and linear energy transfer of 250 kVp X-rays and plateau and Bragg peak negative pi-mesons. The results support our hypothesis since the size of the increased radioresistant response appears to correspond to the number of radiation induced single-strand breaks. Furthermore, since survival prior to the increased radioresistant response (< 0.2 Gy) was LET-independent, these data support the notion that the increased radioresistant response may dictate the overall survival response to higher doses. However, while these data provide further circumstantial evidence for the involvement of DNA strand breaks in the triggering of increased radioresistance, more direct conclusions cannot be made. The data are not accurate enough to detect structure in the single-strand break profiles, the production of single-strand breaks being apparently linear with dose.

  4. The response of Chinese hamster V79-379A cells exposed to negative Pi-mesons: Evidence that increased radioresistance is dependent on linear energy transfer

    SciTech Connect

    Marples, B.; Zhou, H.; Skov, K.A.; Lam, G.K.Y.

    1994-04-01

    Chinese hamster V79-379A cells exhibit low-dose hypersensitivity to 250 kVp X rays followed by an increased radioresistant response over the dose range 0.5-1 Gy. This phenomenon is not seen with neutrons. It was therefore postulated the induction of radioresistance might develop as a response to a cellular event(s) which predominates after low- and not high-LET radiation. To test this hypothesis, we measured the survival response of V79-379A cells exposed to pions. Clonogenic survival was assessed for cells irradiated in the Bragg peak (35 keV/{mu}m) and plateau region (10-20 keV/{mu}m) of the beam, using an automated microscope (DMIPS cell analyzer). As expected, peak pions were found to be more effective per unit of dose at killing cells than plateau pions. The survival curve for cells irradiated in the plateau of the pion beam was found to incorporate a region of low-dose hypersensitivity and increased radioresistance, the effective D{sub 0} was dose-dependent, ranging from 3.5-5. This was not seen with peak pions, where the effective D{sub 0} was, on average, constant reflecting a single-exponential survival curve. Fitting the data with an induced repair model indicates that the phenomenon of increased radioresistance is almost certainly dependent on LET. 23 refs., 2 figs., 1 tab.

  5. Preparatory clinical studies of Pi-mesons at TRIUMF

    SciTech Connect

    Goodman, G.B.; Dixon, P.; Lam, G.K.; Harrison, R.; Kornelsen, R.O.; Ludgate, C.M.; Flores, A.D.

    1985-01-01

    Eighty patients have been treated with Pi-mesons (pions) at TRIUMF between 1979-1984. The patients had tumors rarely curable by standard methods and had no prior radiotherapy. The distribution by site included skin, metastatic nodules (13), brain, glioblastoma multiforme (32), pelvis, rectosigmoid (15), prostate (12), bladder (7), and ovary (1). The studies involve serial escalations of pion dose until maximum tissue tolerance is reached, monitoring the response at each dose increment. Sites were chosen for study where lack of local control is a significant cause of treatment failure with conventional radiation therapy. The low dose rate and the available beam access at TRIUMF limit the number of patients treated and the volume treatable. A 3-D treatment planning program is in use, and a 3-D display of the dose distribution delivered in brain tumor treatments has been developed using the PET scanner. In practice, new methods introduced for measurement of tissue response include tumor growth delay curves, fine-needle biopsy mapping, and PET scanning of brain tumors. The use of endoscopic assessment of the rectosigmoid region is emphasized. Treatment results of glioblastoma multiforme show that the median survival for patients treated to 125 pion cGy/fx is in the range of 187-198 days; for patients receiving 170 cGy per dose/fraction (fx) the range is 290-315 days, and for those receiving 200-220 cGy/fx the median survival is in excess of 290 days. For pelvic malignancies the local control obtained with doses of 2500 cGy or less was 50% in 12 asable patients; it was 75% in 20 patients who had 3000 cGy or more.

  6. Negative-Frequency Resonant Radiation

    NASA Astrophysics Data System (ADS)

    Rubino, E.; McLenaghan, J.; Kehr, S. C.; Belgiorno, F.; Townsend, D.; Rohr, S.; Kuklewicz, C. E.; Leonhardt, U.; König, F.; Faccio, D.

    2012-06-01

    Optical solitons or solitonlike states shed light to blueshifted frequencies through a resonant emission process. We predict a mechanism by which a second propagating mode is generated. This mode, called negative resonant radiation, originates from the coupling of the soliton mode to the negative-frequency branch of the dispersion relation. Measurements in both bulk media and photonic-crystal fibers confirm our predictions.

  7. Nonelastic interactions of nucleons and pi mesons with complex nuclei at energies below 3 GeV.

    NASA Technical Reports Server (NTRS)

    Bertini, H. W.

    1972-01-01

    Calculation of nonelastic interactions corresponding to continuum-state transitions using the intranuclear-cascade evaporation approach. Spallation yields, energy- and angle-dependent spectra, particle multiplicities, and nonelastic cross sections are calculated for incident nucleons and pi mesons with energies below 3 GeV on complex nuclei. Comparisons with experimental data are made, and, in general, the agreement is good. Discrepancies in these comparisons are discussed with respect to the deficiencies in the model.

  8. A Analysis of Neutral pi Mesons Produced in Minimum Bias 515 Gev/c Negative Pion Nuclear Collisions

    NASA Astrophysics Data System (ADS)

    Kuehler, John Fredrick

    1995-01-01

    The results of an analysis of the minimum bias data sample collected from experiment E706 at Fermi National Accelerator Laboratory are reported on. The measured invariant differential cross sections, E{dsigma over d^3p}, for pi ^0 production from the interaction of a 515 GeV/c pi^- beam incident on the nuclear targets of Beryllium, pi^ - + {bf Be} to pi^0 + {bf X}, and Copper, pi ^- + {bf Cu} to pi^0 + {bf X}, are measured in terms of p_{t} (transverse momentum) over the range of.6 GeV/c <= p_{t } <= 2. GeV/c. Further, the cross sections for particle production off of nuclear targets can be parameterized as E{dsigmaover d^3p} = sigma_0A^{ alpha(p_{t})}, and the alpha(p_{t}) dependence of the differential cross section is reported on.

  9. Negative radiation pressure on gain medium structures.

    PubMed

    Mizrahi, Amit; Fainman, Yeshaiahu

    2010-10-15

    We demonstrate negative radiation pressure on gain medium structures, such that light amplification may cause a nanoscale body to be pulled toward a light source. Optically large gain medium structures, such as slabs and spheres, as well as deep subwavelength bodies, may experience this phenomenon. The threshold gain for radiation pressure reversal is obtained analytically for Rayleigh spheres, thin cylinders, and thin slabs. This threshold vanishes when the gain medium structure is surrounded by a medium with a matched refractive index, thus eliminating the positive scattering forces.

  10. Negative radiation pressure exerted on kinks

    NASA Astrophysics Data System (ADS)

    Forgács, Péter; Lukács, Árpád; Romańczukiewicz, Tomasz

    2008-06-01

    The interaction of a kink and a monochromatic plane wave in one dimensional scalar field theories is studied. It is shown that in a large class of models the radiation pressure exerted on the kink is negative, i.e. the kink is pulled towards the source of the radiation. This effect has been observed by numerical simulations in the ϕ4 model, and it is explained by a perturbative calculation assuming that the amplitude of the incoming wave is small. Quite importantly the effect is shown to be robust against small perturbations of the ϕ4 model. In the sine-Gordon (SG) model the time-averaged radiation pressure acting on the kink turns out to be zero. The results of the perturbative computations in the SG model are shown to be in full agreement with an analytical solution corresponding to the superposition of a SG kink with a cnoidal wave. It is also demonstrated that the acceleration of the kink satisfies Newton’s law.

  11. Negative radiation pressure exerted on kinks

    SciTech Connect

    Forgacs, Peter; Lukacs, Arpad; Romanczukiewicz, Tomasz

    2008-06-15

    The interaction of a kink and a monochromatic plane wave in one dimensional scalar field theories is studied. It is shown that in a large class of models the radiation pressure exerted on the kink is negative, i.e. the kink is pulled towards the source of the radiation. This effect has been observed by numerical simulations in the {phi}{sup 4} model, and it is explained by a perturbative calculation assuming that the amplitude of the incoming wave is small. Quite importantly the effect is shown to be robust against small perturbations of the {phi}{sup 4} model. In the sine-Gordon (SG) model the time-averaged radiation pressure acting on the kink turns out to be zero. The results of the perturbative computations in the SG model are shown to be in full agreement with an analytical solution corresponding to the superposition of a SG kink with a cnoidal wave. It is also demonstrated that the acceleration of the kink satisfies Newton's law.

  12. Negative Radiation Pressure in Case of Two Interacting Fields

    NASA Astrophysics Data System (ADS)

    Romańczukiewicz, T.

    2008-12-01

    The new mechanism of an interesting phenomenon of the negative radiation pressure is presented. Force exerted by radiation on the kink in a simple toy model is calculated using perturbation scheme. The results are compared with numerical calculations. The interaction of vortices and radiation is discussed and possible explanation of the negative radiation pressure is examined.

  13. Radiation quality of beams of negative pions

    SciTech Connect

    Dicello, J.F.; Brenner, D.J.

    1981-01-01

    As a negative pion stops in tissue, it attaches itself to an adjacent atom to form a mesonic atom. Subsequently, the wave function of the pion interacts with that of the nucleus and the pion is absorbed. Because the energy associated with the rest mass of the pion is greater than the separation energy of the nuclear particles, the nucleus disintegrates (pion star). In tissue, approximately 40 MeV goes into overcoming the binding energies; 20 MeV goes into kinetic energy of charged particles; 80 MeV goes into kinetic energy of neutrons. In cases where biological studies are performed with beams of negative pions, as much as 20% of the total absorbed dose in the treatment volume and about 50% of the high-LET dose (> 100 keV/..mu..m) can result from neutrons. The degree of biological response and the variation of that response throughout the treatment volume can be altered by the neutron dose.

  14. Negative radiation pressure and negative effective refractive index via dielectric birefringence.

    PubMed

    Nemirovsky, Jonathan; Rechtsman, Mikael C; Segev, Mordechai

    2012-04-09

    We show that light guided in a planar dielectric slab geometry incorporating a biaxial medium has lossless modes with group and phase velocities in opposite directions. Particles in a vacuum gap inserted into the structure experience negative radiation pressure: the particles are pulled by light rather than pushed by it. This effectively one-dimensional dielectric structure represents a new geometry for achieving negative radiation pressure in a wide range of frequencies with minimal loss. Moreover, this geometry provides a straightforward platform for experimentally resolving the Abrahams-Minkowski dilemma.

  15. Left-handed metamaterials operating in the visible: negative refraction and negative radiation pressure

    NASA Astrophysics Data System (ADS)

    Lezec, Henri

    2009-03-01

    Forty years ago, V. Veselago derived the electromagnetic properties of a hypothetical material having simultaneously-negative values of electric permittivity and magnetic permeability [1]. Such a material, denominated ``left-handed'', was predicted to exhibit a negative index of refraction, as well as a number of other counter-intuitive optical properties. For example, it was hypothesized that a perfect mirror illuminated with a plane wave would experience a negative radiation pressure (pull) when immersed in a left-handed medium, as opposed to the usual positive radiation pressure experienced when facing a dielectric medium such as air or glass. Since left-handed materials are not available in nature, considerable efforts are currently under way to implement them under the form of artificial ``metamaterials'' -- composite media with tailored bulk optical characteristics resulting from constituent structures which are smaller in both size and density than the effective wavelength in the medium. Here we show how surface-plasmon modes propagating in a stacked array of metal-insulator-metal (MIM) waveguides can be harnessed to yield a volumetric left-handed metamaterial characterized by an in-plane-isotropic negative index of refraction over a broad frequency range spanning the blue and green. By sculpting this material with a focused-ion beam we realize prisms and micro-cantilevers which we use to demonstrate, for the first time, (a) in-plane isotropic negative-refraction at optical frequencies, and (b) negative radiation pressure. We predict and experimentally verify a negative ``superpressure'', the magnitude of which exceeds the photon pressure experienced by a perfect mirror by more than a factor of two. 1) V. Veselago, Sov. Phys. Usp. 10, p.509 (1968).

  16. The Evolution of External Beam Radiation Therapy (EBRT) from a Technological Perspective.

    NASA Astrophysics Data System (ADS)

    Detorie, Nicholas

    2008-03-01

    Since the discovery of x-rays by Roentgen in 1895 ionizing radiations have been used as a treatment for cancer. Such treatments have been based on either implantation of radioactive materials at the site of disease or by aiming external radiation beams at the diseased site. This later method is referred to as teletherapy because the beams originate from a location outside of the body distant from the disease site itself. A brief review of the basic radiation biology will be given to illustrate the rationale for therapeutic use of ionizing radiations and the effects of beam energy and beam type- particulate or photon. The remainder of the presentation will focus on the technological teletherapy developments supported by the required physical properties of the beams and their associated characteristics that make them suitable for patient treatments. Chronological highlights will include the following sources or devices: superficial x-rays, orthovaltage x-rays, megavoltage x-rays and Cobalt 60 photons, electron beams, neutron beams, negative pi mesons, protons, and heavy ions. The presentation will illustrate how the physical beam properties have been incorporated into modern radiation treatment devices, many of which are equipped with radiation imaging capability. Such devices include: linacs equipped with multileaf collimators for beam shaping and intensity modulation, the Gamma Knife for precise and accurate irradiation of brain tumors or arterial-venous malformations (AVM), the robotic arm based Cyber Knife, and the Helical Tomotherapy unit.

  17. Using Thermal Radiation in Detection of Negative Obstacles

    NASA Technical Reports Server (NTRS)

    Rankin, Arturo L.; Matthies, Larry H.

    2009-01-01

    A method of automated detection of negative obstacles (potholes, ditches, and the like) ahead of ground vehicles at night involves processing of imagery from thermal-infrared cameras aimed at the terrain ahead of the vehicles. The method is being developed as part of an overall obstacle-avoidance scheme for autonomous and semi-autonomous offroad robotic vehicles. The method could also be applied to help human drivers of cars and trucks avoid negative obstacles -- a development that may entail only modest additional cost inasmuch as some commercially available passenger cars are already equipped with infrared cameras as aids for nighttime operation.

  18. Geometrical interpretation of negative radiation forces of acoustical Bessel beams on spheres

    NASA Astrophysics Data System (ADS)

    Zhang, Likun; Marston, Philip L.

    2011-09-01

    Various researchers have predicted situations where the acoustical or optical radiation force on a sphere centered on a Bessel beam is opposite the direction of beam propagation. We develop the analogy between acoustical and optical radiation forces of arbitrary-order helicoidal and ordinary Bessel beams to gain insight into negative radiation forces. The radiation force is expressed in terms of the asymmetry of the scattered field, the scattered power, the absorbed power, and the conic angle of the Bessel beam and is related to the partial-wave coefficients for the scattering. Negative forces only occur when the scattering into the backward hemisphere is suppressed relative to the scattering into the forward hemisphere. Absorbed power degrades negative radiation forces.

  19. Negative axial radiation forces on solid spheres and shells in a Bessel beam.

    PubMed

    Marston, Philip L

    2007-12-01

    Prior computations predict that fluid spheres illuminated by an acoustic Bessel beam can be subjected to a radiation force directed opposite the direction of beam propagation. The prediction of negative acoustic radiation force is extended to the cases of a solid poly(methylmethacrylate) PMMA sphere in water and an empty aluminum spherical shell in water. Compared with the angular scattering patterns for plane wave illumination, the scattering into the back hemisphere is suppressed when the radiation force is negative. This investigation may be helpful in the development of acoustic tweezers and in the development of methods for manipulating objects during space flight.

  20. Electromagnetic Radiation in the Atmosphere Generated by Excess Negative Charge in a Nuclear-Electromagnetic Cascade

    NASA Astrophysics Data System (ADS)

    Malyshevsky, V. S.; Fomin, G. V.

    2017-01-01

    On the basis of the analytical model "PARMA" (PHITS-based Analytical Radiation Model in the Atmosphere), developed to model particle fluxes of secondary cosmic radiation in the Earth's atmosphere, we have calculated the characteristics of radio waves emitted by excess negative charge in an electromagnetic cascade. The results may be of use in an analysis of experimental data on radio emission of electron-photon showers in the atmosphere.

  1. Negative pressure dressing for radiation-associated wound dehiscence after posterolateral thoracotomy.

    PubMed

    Welvaart, Willem N; Oosterhuis, Jan W A; Paul, Marinus A

    2009-05-01

    Wound complications following surgical resection in patients treated with neoadjuvant chemoradiation therapy are common and can be a difficult problem to manage. Negative pressure dressing technology appears to be safe and effective in the treatment of radiation-associated wound complications and can be used in the outpatients clinic setting. The presented case demonstrates that negative pressure dressing also manages the hydropneumothorax as a result of the dehiscence of the thoracic wall.

  2. Supersonic intensity and non-negative intensity for prediction of radiated sound.

    PubMed

    Liu, Daipei; Peters, Herwig; Marburg, Steffen; Kessissoglou, Nicole

    2016-05-01

    Two numerical methods to identify the surface areas of a vibrating structure that radiate sound are presented. The supersonic intensity identifies only the supersonic wave components of the sound field contributing to far-field radiated sound. The supersonic intensity is calculated using a two-dimensional convolution between a spatial radiation filter and the sound field. To compute the spatial radiation filter, the shortest surface distance between two points on the structure is calculated using the geodesic distance method. The non-negative intensity is based on acoustic radiation modes and identifies the radiated sound power from a vibrating structure. Numerical models of a baffled plate, a cylinder and an engine crankcase are presented. The supersonic intensity is shown to be difficult to implement at low frequencies due to the size of the spatial radiation filter and accuracy of the surface distances. A cut-off coefficient associated with the acoustic wavenumber of the spatial radiation filter is used to reduce the aperture error. A comparison of the two intensity-based techniques both in terms of a sound power ratio and the modal assurance criterion is introduced to identify the optimal values of the cut-off coefficients that result in better convergence between the intensity techniques.

  3. Evidence for a negative cloud longwave radiative feedback that weakens the annular mode variability

    NASA Astrophysics Data System (ADS)

    Li, Y.; Thompson, D. W. J.

    2016-12-01

    Southern and northern annular modes are prominent modes of large-scale interannual variability in the extratropics. The variability of annular modes has been widely examined in the context of dry atmospheric dynamics but less so in the context of two-way interactions with clouds. Previous results suggest that cloud radiative effect (CRE) have impact on the long-term mean circulation in both troposphere and stratosphere, and CRE may short the time scale of the North Atlantic Oscillation. Here we use numerical expriments which disable the cloud radiative feedbacks on the circulation to support the idea that cloud may regulate unforced climate variability. We found that cloud longwave radiative effects have a negative feedback that weakens the annular mode variability by 30-50% on month-to-month timescales. The possible physical processes by which cloud radiative effects impact the variability are investigated. Implications for trends in the large-scale atmospheric circulation in a warmer climate are discussed.

  4. Interaction of vacuum ultraviolet excimer laser radiation with fused silica. III. Negative ion formation

    SciTech Connect

    George, Sharon R.; Langford, S. C.; Dickinson, J. T.

    2010-02-15

    We report mass- and time-resolved measurements of negative ions produced by exposing fused silica to 157 nm radiation at fluences below the threshold for optical breakdown. The principal observed negative ions are O{sup -}, Si{sup -}, and SiO{sup -}, in order of decreasing intensity. The peak in the negative ion time-of-flight signals occurs after the peak in the positive ion signal and before the peak in the corresponding neutral atom or molecule signal. The negative ion intensities are strong functions of the degree of overlap between the positive ion and neutral atom densities. We propose that O{sup -}, Si{sup -}, and SiO{sup -} are created after the laser pulse, by electron attachment to these neutral particles and that the electrons participating in attachment events are trapped in the electrostatic potential of the positive ions.

  5. The mechanism of the effect of a plasma layer with negative permittivity on the antenna radiation field

    SciTech Connect

    Wang, Chunsheng Liu, Hui; Jiang, Binhao; Li, Xueai

    2015-06-15

    A model of a plasma–antenna system is developed to study the mechanism of the effect of the plasma layer on antenna radiation. Results show a plasma layer with negative permittivity is inductive, and thus affects the phase difference between electric and magnetic fields. In the near field of antenna radiation, a plasma layer with proper parameters can compensate the capacitivity of the vacuum and enhance the radiation power. In the far field of antenna radiation, the plasma layer with negative permittivity increases the inductivity of the vacuum and reduces the radiation power.

  6. Acoustic manipulation of oscillating spherical bodies: Emergence of axial negative acoustic radiation force

    NASA Astrophysics Data System (ADS)

    Rajabi, Majid; Mojahed, Alireza

    2016-11-01

    In this paper, emergence of negative axial acoustic radiation force on a rigid oscillating spherical body is investigated for acoustic manipulation purposes. The problem of plane acoustic wave scattering from an oscillating spherical body submerged in an ideal acoustic fluid medium is solved. For the case of oscillating direction collinear with the wave propagation wave number vector (desired path), it has been shown that the acoustic radiation force, as a result of nonlinear acoustic wave interaction with bodies can be expressed as a linear function of incident wave field and the oscillation properties of the oscillator (i.e., amplitude and phase of oscillation). The negative (i.e., pulling effects) and positive (i.e., pushing effects) radiation force situations are divided in oscillation complex plane with a specific frequency-dependant straight line. This characteristic line defines the radiation force cancellation state. In order to investigate the stability of the mentioned manipulation strategy, the case of misaligned oscillation of sphere with the wave propagation direction is studied. The proposed methodology may suggest a novel concept of single-beam acoustic handling techniques based on smart carriers.

  7. Postmastectomy radiation therapy in T3 node-negative breast cancer.

    PubMed

    Elmore, Leisha; Deshpande, Anjali; Daly, MacKenzie; Margenthaler, Julie A

    2015-11-01

    In the absence of lymph node involvement, tumor size is arguably the most important prognostic factor for women with breast cancer. Radiation therapy use in the T3 node-negative population is controversial. We investigated the use of postmastectomy radiation therapy (PMRT) in women with T3 node-negative breast cancer. A retrospective cohort study was conducted by identifying women with T3 node-negative breast cancer from the 1988-2009 Surveillance, Epidemiology and End Results database. Our primary outcome was breast cancer-specific survival. Survival curves were generated using the Kaplan-Meier method. Cox proportional hazard ratios (HRs) and propensity score analysis were used to evaluate the impact on survival. We identified 2874 patients with T3 node-negative breast cancer and 961 (33%) received PMRT and 1913 (67%) did not. Statistically significant differences were seen in adjuvant radiation therapy use based on patient age, marital status, tumor grade, tumor size, and receptor status (P < 0.05 for all). Overall survival was lower in the PMRT group in unadjusted analysis (crude HR, 0.718; 95% confidence interval [CI], 0.614-0.840); however, adjusted HRs demonstrated no difference in overall survival (adjusted HR, 0.898; 95% CI, 0.765-1.054). Unadjusted analysis of breast cancer-specific survival demonstrated no difference between those who received PMRT and those who did not (crude HR, 0.834; 95% CI, 0.682-1.021). Propensity score analysis demonstrated no difference in breast cancer-specific survival based on PMRT use (adjusted HR, 0.939; 95% CI, 0.762-1.157). Analysis of the Surveillance, Epidemiology and End Results database suggests that receipt of PMRT is not clinically beneficial in T3 node-negative breast cancer. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. High-energy electrons in the inner radiation belt of the earth

    NASA Astrophysics Data System (ADS)

    Basilova, R. N.; Gusev, A. A.; Pugacheva, G. I.; Titenkov, A. F.

    1982-08-01

    Measurements of electron fluxes with energies greater than 40 MeV obtained by Kosmos 490, Salut 6, and Interkosmos 17 satellites at heights of 270-500 km in the Brazilian anomaly region are discussed. The observed electron flux is explained in terms of the decomposition of pi meson, produced by the interaction between high-energy protons (0.35-1 GeV) of the inner radiation belt and atoms of the residual atmosphere. A formula describing the electron flux is presented.

  9. Surgery and radiation therapy of triple-negative breast cancers: From biology to clinics.

    PubMed

    Bernier, Jacques; Poortmans, Philip M P

    2016-08-01

    Triple negative breast cancer refers to tumours lacking the expression of the three most used tumour markers, namely oestrogen receptors, progesterone receptors, and human epidermal growth factor receptor 2 (HER2). These cancers are known to carry a more dismal prognosis than the other molecular subtypes. Whether a more aggressive local-regional treatment is warranted or not in patients with triple-negative breast cancer is still a matter of debate. Indeed there remain a number of grey zones with respect to the optimization of the extent and the timing of surgery and radiation therapy (RT) in this patient population, also in consideration of the significant heterogeneity in biological behaviour and response to treatment identified for these tumours. The objective of this review is to provide an insight into the biological and clinical behaviour of triple-negative breast cancers and revisit the most recent advances in their management, focussing on local-regional treatments.

  10. Analysis of radiation therapy in a model of triple-negative breast cancer brain metastasis.

    PubMed

    Smart, DeeDee; Garcia-Glaessner, Alejandra; Palmieri, Diane; Wong-Goodrich, Sarah J; Kramp, Tamalee; Gril, Brunilde; Shukla, Sudhanshu; Lyle, Tiffany; Hua, Emily; Cameron, Heather A; Camphausen, Kevin; Steeg, Patricia S

    2015-10-01

    Most cancer patients with brain metastases are treated with radiation therapy, yet this modality has not yet been meaningfully incorporated into preclinical experimental brain metastasis models. We applied two forms of whole brain radiation therapy (WBRT) to the brain-tropic 231-BR experimental brain metastasis model of triple-negative breast cancer. When compared to sham controls, WBRT as 3 Gy × 10 fractions (3 × 10) reduced the number of micrometastases and large metastases by 87.7 and 54.5 %, respectively (both p < 0.01); whereas a single radiation dose of 15 Gy × 1 (15 × 1) was less effective, reducing metastases by 58.4 % (p < 0.01) and 47.1 % (p = 0.41), respectively. Neuroinflammation in the adjacent brain parenchyma was due solely to a reaction from metastases, and not radiotherapy, while adult neurogenesis in brains was adversely affected following both radiation regimens. The nature of radiation resistance was investigated by ex vivo culture of tumor cells that survived initial WBRT ("Surviving" cultures). The Surviving cultures surprisingly demonstrated increased radiosensitivity ex vivo. In contrast, re-injection of Surviving cultures and re-treatment with a 3 × 10 WBRT regimen significantly reduced the number of large and micrometastases that developed in vivo, suggesting a role for the microenvironment. Micrometastases derived from tumor cells surviving initial 3 × 10 WBRT demonstrated a trend toward radioresistance upon repeat treatment (p = 0.09). The data confirm the potency of a fractionated 3 × 10 WBRT regimen and identify the brain microenvironment as a potential determinant of radiation efficacy. The data also nominate the Surviving cultures as a potential new translational model for radiotherapy.

  11. Radiation therapy in the locoregional treatment of triple-negative breast cancer.

    PubMed

    Moran, Meena S

    2015-03-01

    This Review assesses the relevant data and controversies regarding the use of radiotherapy for, and locoregional management of, women with triple-negative breast cancer (TNBC). In view of the strong association between BRCA1 and TNBC, knowledge of baseline mutation status can be useful to guide locoregional treatment decisions. TNBC is not a contraindication for breast conservation therapy because data suggest increased locoregional recurrence risks (relative to luminal subtypes) with breast conservation therapy or mastectomy. Although a boost to the tumour bed should routinely be considered after whole breast radiation therapy, TNBC should not be the sole indication for post-mastectomy radiation, and accelerated delivery methods for TNBC should be offered on clinical trials. Preliminary data implying a relative radioresistance for TNBC do not imply radiation omission because radiation provides an absolute locoregional risk reduction. At present, the integration of subtypes in locoregional management decisions is still in its infancy. Until level 1 data supporting treatment decisions based on subtypes are available, standard locoregional management principles should be adhered to. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Optical emission and peak electromagnetic power radiated by negative return strokes in rocket-triggered lightning

    NASA Astrophysics Data System (ADS)

    Quick, Mason G.; Krider, E. Philip

    2015-12-01

    Calibrated measurements of the optical radiation produced by negative return strokes in rocket-triggered lightning (RTL) have been made in the visible and near infrared (VNIR) spectral region in correlation with currents measured at the channel base. Using a simple transmission-line model, the currents have been used to estimate the peak electromagnetic (EM) fields and Poynting power that are radiated in the time-domain (i.e. from about 1 kHz to 3 MHz). The results show that the optical power radiated by RTL at the time of the peak current has a mean and standard deviation of 130±120 MW, a value that is only about 5% of the Poynting power that is radiated into the upper half-space at that time. These results are in good agreement with similar measurements made on the subsequent return strokes in natural lightning that remain in a pre-existing channel. Our methods and assumptions are similar to those of (Guo and Krider, 1983; Krider and Guo, 1983; Quick and Krider, 2013).

  13. Acoustic manipulation of active spherical carriers: Generation of negative radiation force

    NASA Astrophysics Data System (ADS)

    Rajabi, Majid; Mojahed, Alireza

    2016-09-01

    This paper examines theoretically a novel mechanism of generating negative (pulling) radiation force for acoustic manipulation of spherical carriers equipped with piezoelectric actuators in its inner surface. In this mechanism, the spherical particle is handled by common plane progressive monochromatic acoustic waves instead of zero-/higher- order Bessel beams or standing waves field. The handling strategy is based on applying a spatially uniform harmonic electrical voltage at the piezoelectric actuator with the same frequency of handling acoustic waves, in order to change the radiation force effect from repulsive (away from source) to attractive (toward source). This study may be considered as a start point for development of contact-free precise handling and entrapment technology of active carriers which are essential in many engineering and medicine applications.

  14. Acoustic manipulation of active spherical carriers: Generation of negative radiation force

    SciTech Connect

    Rajabi, Majid Mojahed, Alireza

    2016-09-15

    This paper examines theoretically a novel mechanism of generating negative (pulling) radiation force for acoustic manipulation of spherical carriers equipped with piezoelectric actuators in its inner surface. In this mechanism, the spherical particle is handled by common plane progressive monochromatic acoustic waves instead of zero-/higher- order Bessel beams or standing waves field. The handling strategy is based on applying a spatially uniform harmonic electrical voltage at the piezoelectric actuator with the same frequency of handling acoustic waves, in order to change the radiation force effect from repulsive (away from source) to attractive (toward source). This study may be considered as a start point for development of contact-free precise handling and entrapment technology of active carriers which are essential in many engineering and medicine applications.

  15. Search for deeply bound pionic states in 208Pb via radiative atomic capture of negative pions

    NASA Astrophysics Data System (ADS)

    Raywood, K. J.; Lange, J. B.; Jones, G.; Pavan, M.; Sevior, M. E.; Hutcheon, D. A.; Olin, A.; Ottewell, D.; Yen, S.; Lee, S. J.; Sim, K. S.; Altman, A.; Friedman, E.; Trudel, A.

    1997-05-01

    A search for narrow, deeply bound pionic atom states via atomic radiative capture of negative pions in a target of 208Pb was carried out for pion kinetic energies of 20 and 25 MeV. Although no clear signature of any such gamma ray emission could be observed in the data, fits of the gamma ray spectra between the energies of 12 and 42 MeV involving a quadratic background together with a pair of peaks (1s, 2p) whose relative intensity was taken from theory yielded an overall strength for the peaks which are consistent (to a 67% confidence level) with radiative capture whose integrated cross section is 20.0 +/- 10.0 μb/sr at 90° for 20 MeV incident pions. A lower probability (40% confidence level) result was obtained when the fit was carried out without the peaks included, just the continuum background.

  16. Negative-mass mitigation of Coulomb repulsion for terahertz undulator radiation of electron bunches

    SciTech Connect

    Balal, N.; Magory, E.; Bandurkin, I. V.; Bratman, V. L.; Savilov, A. V.

    2015-10-19

    It is proposed to utilize the effect of negative mass for stabilization of the effective axial size of very dense and short electron bunches produced by photo-injector guns by using combined undulator and strong uniform magnetic fields. It has been shown that in the “abnormal” regime, an increase in the electron energy leads to a decrease in the axial velocity of the electron; due to the negative-mass effect, the Coulomb repulsion of electrons leads to their attraction and formation of a fairly stable and compact bunch “nucleus.” An undulator with a strong uniform magnetic field providing the negative-mass effect is designed for an experimental source of terahertz radiation. The use of the negative-mass regime in this experiment should result in a long-pulse coherent spontaneous undulator emission from a short dense moderately relativistic (5.5 MeV) photo-injector electron bunch with a high (up to 20%) efficiency and a narrow frequency spectrum.

  17. [Nasal endoscope negative pressure cleaning and sinupret drops to treat radiation nasosinusitis].

    PubMed

    Lin, Wenbiao; Quan, Chaokun; Zhang, Longcheng

    2015-12-01

    To observe the effect of nasal endoscope negative pressure cleaning and sinupret drops to treat radiation nasosinusitis (RNS). One hundred and fifty-three patients with nasopharyngeal carcinoma were randomly divided into treatment group A, B, C . Group A using nasal endoscope negative pressure cleaning and sinupret drops, group B using nasal endoscope negative pressure cleaning and normal saline spray washing, group C using saline nasal irrigation through nasal catheter. All patients with sinusitis condition were evaluated at the end of radiotherapy, three months and six months after radiotherapy. Comparison between groups, three periods of RNS incidence, moderate to severe RNS incidence are A < B < C. Six months after radiotherapy, group A compared with group C, there are significant difference (P < 0.01), group A and group C compared with group B respectively, the difference was statistically significant (P < 0.05). Nasal endoscope negative pressure cleaning and sinupret drops can significantly reduce the long-term incidence of RNS, especially obviously reduce the incidence of moderate to severe RNS,which is a practical and effective method to treat RNS.

  18. [Detection of endotoxins of Gram-negative bacteria on the basis of electromagnetic radiation frequency spectrum].

    PubMed

    Likhoded, V G; Kuleshova, N V; Sergieva, N V; Konev, Iu V; Trubnikova, I A; Sudzhian, E V

    2007-01-01

    Method of Gram-negative bacteria endotoxins detection on the basis of their own spectrum of electromagnetic radiation frequency was developed. Frequency spectrum typical for chemotype Re glycolipid, which is a part of lypopolysaccharides in the majority of Gram-negative bacteria, was used. Two devices--"Mini- Expert-DT" (manufactured by IMEDIS, Moscow) and "Bicom" (manufactured by Regumed, Germany)--were used as generators of electromagnetic radiation. Detection of endotoxin using these devices was performed by electropuncture vegetative resonance test. Immunoenzyme reaction with antibodies to chemotype Re glycolipid was used during analysis of preparations for assessment of resonance-frequency method specificity. The study showed that resonance-frequency method can detect lypopolysaccharides of different enterobacteria in quantities up to 0.1 pg as well as bacteria which contain lypopolysaccharides. At the same time, this method does not detect such bacteria as Staphylococcus aureus, Bifidobacterium spp., Lactobacillus spp., and Candida albicans. The method does not require preliminary processing of blood samples and can be used for diagnostics of endotoxinemia, and detection of endotoxins in blood samples or injection solutions.

  19. Radiation-enhanced therapeutic targeting of galectin-1 enriched malignant stroma in triple negative breast cancer

    PubMed Central

    Upreti, Meenakshi; Jyoti, Amar; Johnson, Sara E.; Swindell, Elden P.; Napier, Dana; Sethi, Pallavi; Chan, Ryan; Feddock, Jonathan M.; Weiss, Heidi L.; O'Halloran, Thomas V.; Mark Evers, B.

    2016-01-01

    Currently there are no FDA approved targeted therapies for Triple Negative Breast Cancer (TNBC). Ongoing clinical trials for TNBC have focused primarily on targeting the epithelial cancer cells. However, targeted delivery of cytotoxic payloads to the non-transformed tumor associated-endothelium can prove to be an alternate approach that is currently unexplored. The present study is supported by recent findings on elevated expression of stromal galectin-1 in clinical samples of TNBC and our ongoing findings on stromal targeting of radiation induced galectin-1 by the anginex-conjugated arsenic-cisplatin loaded liposomes using a novel murine tumor model. We demonstrate inhibition of tumor growth and metastasis in response to the multimodal nanotherapeutic strategy using a TNBC model with orthotopic tumors originating from 3D tumor tissue analogs (TTA) comprised of tumor cells, endothelial cells and fibroblasts. The ‘rigorous’ combined treatment regimen of radiation and targeted liposomes is also shown to be well tolerated. More importantly, the results presented provide a means to exploit clinically relevant radiation dose for concurrent receptor mediated enhanced delivery of chemotherapy while limiting overall toxicity. The proposed study is significant as it falls in line with developing combinatorial therapeutic approaches for stroma-directed tumor targeting using tumor models that have an appropriate representation of the TNBC microenvironment. PMID:27223428

  20. Physical principles of the amplification of electromagnetic radiation due to negative electron masses in a semiconductor superlattice

    NASA Astrophysics Data System (ADS)

    Shorokhov, A. V.; Pyataev, M. A.; Khvastunov, N. N.; Hyart, T.; Kusmartsev, F. V.; Alekseev, K. N.

    2015-02-01

    In a superlattice placed in crossed static electric and magnetic fields, under certain conditions, the inversion of electron population can appear at which the average energy of electrons is above the middle of the mini-band and the effective mass of the electron is negative. This is the implementation of the negative effective mass amplifier and generator (NEMAG) in the superlattice. It can result in the amplification and generation of terahertz radiation even in the absence of negative differential conductivity.

  1. Patterning Characteristics of a Chemically-Amplified Negative Resist in Synchrotron Radiation Lithography

    NASA Astrophysics Data System (ADS)

    Deguchi, Kimiyoshi; Miyoshi, Kazunori; Ishii, Tetsuyoshi; Matsuda, Tadahito

    1992-09-01

    To explore the applicability of synchrotron radiation X-ray lithography for fabricating sub-quartermicron devices, we investigate the patterning characteristics of the chemically-amplified negative resist SAL601-ER7. Since these characteristics depend strongly on the conditions of the chemical amplification process, the effects of post-exposure baking and developing conditions on sensitivity and resolution are examined. The resolution-limiting factors are investigated, revealing that pattern collapse during the development process and fog caused by Fresnel diffraction, photo-electron scattering, and acid diffusion in the resist determine the resolution and the maximum aspect ratio of the lines and spaces pattern. Using the model of a swaying beam supported at one end, it is shown that pattern collapse depends on the resist pattern’s flexural stiffness. Patterning stability, which depends on the delay time between exposure and baking, is also discussed.

  2. The Negative Impact of Stark Law Exemptions on Graduate Medical Education and Health Care Costs: The Example of Radiation Oncology

    SciTech Connect

    Anscher, Mitchell S.; Anscher, Barbara M.; Bradley, Cathy J.

    2010-04-15

    Purpose: To survey radiation oncology training programs to determine the impact of ownership of radiation oncology facilities by non-radiation oncologists on these training programs and to place these findings in a health policy context based on data from the literature. Methods and Materials: A survey was designed and e-mailed to directors of all 81 U.S. radiation oncology training programs in this country. Also, the medical and health economic literature was reviewed to determine the impact that ownership of radiation oncology facilities by non-radiation oncologists may have on patient care and health care costs. Prostate cancer treatment is used to illustrate the primary findings. Results: Seventy-three percent of the surveyed programs responded. Ownership of radiation oncology facilities by non-radiation oncologists is a widespread phenomenon. More than 50% of survey respondents reported the existence of these arrangements in their communities, with a resultant reduction in patient volumes 87% of the time. Twenty-seven percent of programs in communities with these business arrangements reported a negative impact on residency training as a result of decreased referrals to their centers. Furthermore, the literature suggests that ownership of radiation oncology facilities by non-radiation oncologists is associated with both increased utilization and increased costs but is not associated with increased access to services in traditionally underserved areas. Conclusions: Ownership of radiation oncology facilities by non-radiation oncologists appears to have a negative impact on residency training by shifting patients away from training programs and into community practices. In addition, the literature supports the conclusion that self-referral results in overutilization of expensive services without benefit to patients. As a result of these findings, recommendations are made to study further how physician ownership of radiation oncology facilities influence graduate

  3. The negative impact of stark law exemptions on graduate medical education and health care costs: the example of radiation oncology.

    PubMed

    Anscher, Mitchell S; Anscher, Barbara M; Bradley, Cathy J

    2010-04-01

    To survey radiation oncology training programs to determine the impact of ownership of radiation oncology facilities by non-radiation oncologists on these training programs and to place these findings in a health policy context based on data from the literature. A survey was designed and e-mailed to directors of all 81 U.S. radiation oncology training programs in this country. Also, the medical and health economic literature was reviewed to determine the impact that ownership of radiation oncology facilities by non-radiation oncologists may have on patient care and health care costs. Prostate cancer treatment is used to illustrate the primary findings. Seventy-three percent of the surveyed programs responded. Ownership of radiation oncology facilities by non-radiation oncologists is a widespread phenomenon. More than 50% of survey respondents reported the existence of these arrangements in their communities, with a resultant reduction in patient volumes 87% of the time. Twenty-seven percent of programs in communities with these business arrangements reported a negative impact on residency training as a result of decreased referrals to their centers. Furthermore, the literature suggests that ownership of radiation oncology facilities by non-radiation oncologists is associated with both increased utilization and increased costs but is not associated with increased access to services in traditionally underserved areas. Ownership of radiation oncology facilities by non-radiation oncologists appears to have a negative impact on residency training by shifting patients away from training programs and into community practices. In addition, the literature supports the conclusion that self-referral results in overutilization of expensive services without benefit to patients. As a result of these findings, recommendations are made to study further how physician ownership of radiation oncology facilities influence graduate medical education, treatment patterns and utilization

  4. A collisional radiative model of hydrogen plasmas developed for diagnostic purposes of negative ion sources

    SciTech Connect

    Iordanova, Snejana Paunska, Tsvetelina

    2016-02-15

    A collisional radiative model of low-pressure hydrogen plasmas is elaborated and applied in optical emission spectroscopy diagnostics of a single element of a matrix source of negative hydrogen ions. The model accounts for the main processes determining both the population densities of the first ten states of the hydrogen atom and the densities of the positive hydrogen ions H{sup +}, H{sub 2}{sup +}, and H{sub 3}{sup +}. In the calculations, the electron density and electron temperature are varied whereas the atomic and molecular temperatures are included as experimentally obtained external parameters. The ratio of the H{sub α} to H{sub β} line intensities is calculated from the numerical results for the excited state population densities, obtained as a solution of the set of the steady-state rate balance equations. The comparison of measured and theoretically obtained ratios of line intensities yields the values of the electron density and temperature as well as of the degree of dissociation, i.e., of the parameters which have a crucial role for the volume production of the negative ions.

  5. Elevated atmospheric CO2 negatively impacts photosynthesis through radiative forcing and physiology-mediated climate feedback

    NASA Astrophysics Data System (ADS)

    Zhu, Peng; Zhuang, Qianlai; Ciais, Philippe; Welp, Lisa; Li, Wenyu; Xin, Qinchuan

    2017-02-01

    Increasing atmospheric CO2 affects photosynthesis involving directly increasing leaf carboxylation rates, stomatal closure, and climatic effects. The direct effects are generally thought to be positive leading to increased photosynthesis, while its climatic effects can be regionally positive or negative. These effects are usually considered to be independent from each other, but they are in fact coupled through interactions between land surface exchanges of gases and heat and the physical climate system. In particular, stomatal closure reduces evapotranspiration and increases sensible heat emissions from ecosystems, leading to decreased atmospheric moisture and precipitation and local warming. We use a coupled earth system model to attribute the influence of the increase in CO2 on gross primary productivity (GPP) during the period of 1930-2011. In our model, CO2 radiative effects cause climate change that has only a negligible effect on global GPP (a reduction of 0.9 ± 2% during the last 80 years) because of opposite responses between tropical and northern biomes. On the other hand, CO2 physiological effects on GPP are both positive, by increased carboxylation rates and water use efficiency (7.1 ± 0.48% increase), and negative, by vegetation-climate feedback reducing precipitation, as a consequence of decreased transpiration and increased sensible heat in areas without water limitation (2.7 ± 1.76% reduction).When considering the coupled atmosphere-vegetation system, negative climate feedback on photosynthesis and plant growth due to the current level of CO2 opposes 29-38% of the gains from direct fertilization effects.

  6. Radiative decays of negative parity heavy baryons in the framework of the light cone QCD sum rules

    NASA Astrophysics Data System (ADS)

    Agamaliev, A. K.; Aliev, T. M.; Savcı, M.

    2017-02-01

    The transition form factors responsible for the radiative ΣQ →ΛQ γ and ΞQ‧ →ΞQ γ decays of the negative parity baryons are examined within light cone QCD sum rules. The decay widths of the radiative transitions are calculated using the obtained results of the form factors. A comparison of our predictions on decay widths with the corresponding widths of positive parity baryons is given.

  7. A Novel Radiation-Induced p53 Mutation Is Not Implicated in Radiation Resistance via a Dominant-Negative Effect

    PubMed Central

    Sun, Yunguang; Myers, Carey Jeanne; Dicker, Adam Paul; Lu, Bo

    2014-01-01

    Understanding the mutations that confer radiation resistance is crucial to developing mechanisms to subvert this resistance. Here we describe the creation of a radiation resistant cell line and characterization of a novel p53 mutation. Treatment with 20 Gy radiation was used to induce mutations in the H460 lung cancer cell line; radiation resistance was confirmed by clonogenic assay. Limited sequencing was performed on the resistant cells created and compared to the parent cell line, leading to the identification of a novel mutation (del) at the end of the DNA binding domain of p53. Levels of p53, phospho-p53, p21, total caspase 3 and cleaved caspase 3 in radiation resistant cells and the radiation susceptible (parent) line were compared, all of which were found to be similar. These patterns held true after analysis of p53 overexpression in H460 cells; however, H1299 cells transfected with mutant p53 did not express p21, whereas those given WT p53 produced a significant amount, as expected. A luciferase assay demonstrated the inability of mutant p53 to bind its consensus elements. An MTS assay using H460 and H1299 cells transfected with WT or mutant p53 showed that the novel mutation did not improve cell survival. In summary, functional characterization of a radiation-induced p53 mutation in the H460 lung cancer cell line does not implicate it in the development of radiation resistance. PMID:24558369

  8. Radiation transport codes for potential applications related to radiobiology and radiotherapy using protons, neutrons, and negatively charged pions

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.

    1972-01-01

    Several Monte Carlo radiation transport computer codes are used to predict quantities of interest in the fields of radiotherapy and radiobiology. The calculational methods are described and comparisions of calculated and experimental results are presented for dose distributions produced by protons, neutrons, and negatively charged pions. Comparisons of calculated and experimental cell survival probabilities are also presented.

  9. Investigation of negative cloud radiative forcing over the Indian subcontinent and adjacent oceans during the summer monsoon season

    NASA Astrophysics Data System (ADS)

    Thampi, B. V.; Roca, R.

    2014-07-01

    Radiative properties of clouds over the Indian subcontinent and nearby oceanic regions (0-25° N, 60-100° E) during the Asian summer monsoon season (June-September) are investigated using the Clouds and Earth's Radiant Energy System (CERES) top-of-the-atmosphere (TOA) flux data. Using multiyear satellite data, the net cloud radiative forcing (NETCRF) at the TOA over the Indian region during the Asian monsoon season is examined. The seasonal mean NETCRF is found to be negative (with its magnitude exceeding ~30 Wm-2) over (1) the northern Bay of Bengal (close to the Myanmar-Thailand coast), (2) the Western Ghats and (3) the coastal regions of Myanmar. Such strong negative NETCRF values observed over the Indian monsoon region contradict the assumption that near cancellation between LWCRF and SWCRF is a generic property of all tropical convective regions. The seasonal mean cloud amount (high and upper middle) and corresponding cloud optical depth observed over the three regions show relatively large values compared to the rest of the Indian monsoon region. Using satellite-derived cloud data, a statistical cloud vertical model delineating the cloud cover and single-scattering albedo was developed for the three negative NETCRF regions. The shortwave (SW), longwave (LW) and net cloud radiative forcing over the three negative NETCRF regions are calculated using the rapid radiative transfer model (RRTM) with the cloud vertical model as input. The NETCRF estimated from CERES observations show good comparison with that computed using RRTM (within the uncertainty limit of CERES observations). Sensitivity tests are conducted using RRTM to identify the parameters that control the negative NETCRF observed over these regions during the summer monsoon season. Increase in atmospheric water vapor content during the summer monsoon season is found to influence the negative NETCRF values observed over the region.

  10. Caloric restriction coupled with radiation decreases metastatic burden in triple negative breast cancer.

    PubMed

    Simone, Brittany A; Dan, Tu; Palagani, Ajay; Jin, Lianjin; Han, Sunny Y; Wright, Christopher; Savage, Jason E; Gitman, Robert; Lim, Meng Kieng; Palazzo, Juan; Mehta, Minesh P; Simone, Nicole L

    2016-09-01

    Metastatic breast cancer is devastating and triple negative breast cancers (TNBC) have a higher propensity for metastasis. Improved local control upfront in this aggressive cancer could potentially decrease its propensity toward metastasis. We sought to determine if using caloric restriction (CR) as a systemic therapy, combined with radiation therapy (IR) to the primary tumor, may impact metastatic disease. An orthotopic mouse model using a highly metastatic, luciferase-tagged TNBC cell line (4T1), was used to generate palpable tumors. Mice were then treated with CR, IR, and a combination of the two. In vivo imaging was performed for metastatic evaluation. Molecular evaluation of the tumors was performed, generating a mechanistic hypothesis for CR, which was then tested with pertinent pathway inhibition in the model. CR significantly increased the time to developing metastases, decreased the overall number and volume of lung metastases, and increased survival. CR decreased proliferation, increased apoptosis and globally downregulated the IGF-1R signaling pathway. Adding an IGF-1R/INSR inhibitor to local IR in vivo accomplished a decrease in metastases similar to CR plus IR, demonstrating the importance of the IGF-1R signaling pathway, and underscoring it as a possible mechanism for CR. CR decreased metastatic burden and therefore may complement cytotoxic therapies being used in the clinical setting for metastatic disease. Downregulation of the IGF-1R pathway, is in part responsible for this response and modulating IGF-1R directly resulted in similar improved progression-free survival. The novel use of CR has the potential to enhance clinical outcomes for patients with metastatic breast cancer.

  11. Caloric restriction coupled with radiation decreases metastatic burden in triple negative breast cancer

    PubMed Central

    Simone, Brittany A.; Dan, Tu; Palagani, Ajay; Jin, Lianjin; Han, Sunny Y.; Wright, Christopher; Savage, Jason E.; Gitman, Robert; Lim, Meng Kieng; Palazzo, Juan; Mehta, Minesh P.; Simone, Nicole L.

    2016-01-01

    ABSTRACT Purpose: Metastatic breast cancer is devastating and triple negative breast cancers (TNBC) have a higher propensity for metastasis. Improved local control upfront in this aggressive cancer could potentially decrease its propensity toward metastasis. We sought to determine if using caloric restriction (CR) as a systemic therapy, combined with radiation therapy (IR) to the primary tumor, may impact metastatic disease. Methods: An orthotopic mouse model using a highly metastatic, luciferase-tagged TNBC cell line (4T1), was used to generate palpable tumors. Mice were then treated with CR, IR, and a combination of the two. In vivo imaging was performed for metastatic evaluation. Molecular evaluation of the tumors was performed, generating a mechanistic hypothesis for CR, which was then tested with pertinent pathway inhibition in the model. Results: CR significantly increased the time to developing metastases, decreased the overall number and volume of lung metastases, and increased survival. CR decreased proliferation, increased apoptosis and globally downregulated the IGF-1R signaling pathway. Adding an IGF-1R/INSR inhibitor to local IR in vivo accomplished a decrease in metastases similar to CR plus IR, demonstrating the importance of the IGF-1R signaling pathway, and underscoring it as a possible mechanism for CR. Conclusions: CR decreased metastatic burden and therefore may complement cytotoxic therapies being used in the clinical setting for metastatic disease. Downregulation of the IGF-1R pathway, is in part responsible for this response and modulating IGF-1R directly resulted in similar improved progression-free survival. The novel use of CR has the potential to enhance clinical outcomes for patients with metastatic breast cancer. PMID:27027731

  12. A study of the diffuse galactic gamma radiation

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.; Kniffen, D. A.

    1982-01-01

    Assuming cosmic rays pervade the Galaxy, they necessarily produced high energy gamma-rays as they interact with the instellar matter and photons. The cosmic ray nucleon interactions five rise to gamma rays primarily through the decay of pi mesons, giving a unique spectrum with a maximum at approximately 68 MeV. Cosmic ray electrons produce gamma rays through bremsstrahlung, but with a markedly different energy spectral shape, one which decreases monotonically with energy. Cosmic ray electrons also interact with the interstellar starlight, optical and infrared photons, and the blackbody radiation through the Compton process. A model of galactic gamma ray production is discussed, and the predicted spatial distribution and energy spectra are presented. Considering the uncertainty in the point source contributions, the agreement between the theoretical predictions and the gamma ray data seems quite reasonable.

  13. Tunable positive and negative refraction of infrared radiation in graphene-dielectric multilayers

    SciTech Connect

    Zhang, R. Z.; Zhang, Z. M.

    2015-11-09

    Graphene-dielectric multilayers consisting of alternating layers of atom-thick graphene and nanometer-scale dielectric films exhibit characteristics of hyperbolic metamaterials, in which one positive and one negative permittivity are defined for orthogonal directions. Negative permittivity for electric field polarized in the direction parallel to the conductive graphene sheets gives rise to a negative angle of refraction and low-loss transmission for the side-incidence perspective proposed in this work. The Poynting vector tracing demonstrates the switching between positive and negative refraction in the mid-infrared region by tuning the chemical potential of graphene. This adjustable dual-mode metamaterial holds promise for infrared imaging applications.

  14. Tunable positive and negative refraction of infrared radiation in graphene-dielectric multilayers

    NASA Astrophysics Data System (ADS)

    Zhang, R. Z.; Zhang, Z. M.

    2015-11-01

    Graphene-dielectric multilayers consisting of alternating layers of atom-thick graphene and nanometer-scale dielectric films exhibit characteristics of hyperbolic metamaterials, in which one positive and one negative permittivity are defined for orthogonal directions. Negative permittivity for electric field polarized in the direction parallel to the conductive graphene sheets gives rise to a negative angle of refraction and low-loss transmission for the side-incidence perspective proposed in this work. The Poynting vector tracing demonstrates the switching between positive and negative refraction in the mid-infrared region by tuning the chemical potential of graphene. This adjustable dual-mode metamaterial holds promise for infrared imaging applications.

  15. Photoproduction of $\\pi^+ \\pi^-$ meson pairs on the proton

    SciTech Connect

    Marco A. Battaglieri; DeVita, Raffaella; Szczepaniak, Adam P.

    2009-10-01

    The exclusive reaction $\\gamma p \\to p \\pi^+ \\pi^-$ was studied in the photon energy range 3.0 - 3.8 GeV and momentum transfer range $0.4<-t<1.0$ GeV$^2$. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. In this kinematic range the integrated luminosity was about 20 pb$^{-1}$. The reaction was isolated by detecting the $\\pi^+$ and proton in CLAS, and reconstructing the $\\pi^-$ via the missing-mass technique. Moments of the di-pion decay angular distributions were derived from the experimental data. Differential cross sections for the $S$, $P$, and $D$-waves in the $M_{\\pi^+\\pi^-}$ mass range $0.4-1.4$ GeV were derived performing a partial wave expansion of the extracted moments. Besides the dominant contribution of the $\\rho(770)$ meson in the $P$-wave, evidence for the $f_0(980)$ and the $f_2(1270)$ mesons was found in the $S$ and $D$-waves, respectively. The differential production cross sections $d\\sigma/dt$ for individual waves in the mass range of the above-mentioned mesons were extracted. This is the first time the $f_0(980)$ has been measured in a photoproduction experiment.

  16. Atomic radiative transition probabilities using negative-energy orbitals in fully variational wave functions

    NASA Astrophysics Data System (ADS)

    Jitrik, Oliverio; Bunge, Carlos F.

    2005-07-01

    Transition probabilities have been computed using a variational many-electron theory [R. Jáuregui, C.F. Bunge, E. Ley-Koo, Phys. Rev. A 55 (1997) 1781] incorporating positive-energy and negative-energy orbitals without ambiguities, and absolutely free from variational collapse. The results agree with experiment and with other calculations based on the no-pair Hamiltonian where ad hoc negative-energy orbitals occur in first-order corrections to the wave functions.

  17. RB1 status in triple negative breast cancer cells dictates response to radiation treatment and selective therapeutic drugs.

    PubMed

    Robinson, Tyler J W; Liu, Jeff C; Vizeacoumar, Frederick; Sun, Thomas; Maclean, Neil; Egan, Sean E; Schimmer, Aaron D; Datti, Alessandro; Zacksenhaus, Eldad

    2013-01-01

    Triple negative breast cancer (TNBC) includes basal-like and claudin-low subtypes for which only chemotherapy and radiation therapy are currently available. The retinoblastoma (RB1) tumor suppressor is frequently lost in human TNBC. Knockdown of RB1 in luminal BC cells was shown to affect response to endocrine, radiation and several antineoplastic drugs. However, the effect of RB1 status on radiation and chemo-sensitivity in TNBC cells and whether RB1 status affects response to divergent or specific treatment are unknown. Using multiple basal-like and claudin-low cell lines, we hereby demonstrate that RB-negative TNBC cell lines are highly sensitive to gamma-irradiation, and moderately more sensitive to doxorubicin and methotrexate compared to RB-positive TNBC cell lines. In contrast, RB1 status did not affect sensitivity of TNBC cells to multiple other drugs including cisplatin (CDDP), 5-fluorouracil, idarubicin, epirubicin, PRIMA-1(met), fludarabine and PD-0332991, some of which are used to treat TNBC patients. Moreover, a non-biased screen of ∼3400 compounds, including FDA-approved drugs, revealed similar sensitivity of RB-proficient and -deficient TNBC cells. Finally, ESA(+)/CD24(-/low)/CD44(+) cancer stem cells from RB-negative TNBC lines were consistently more sensitive to gamma-irradiation than RB-positive lines, whereas the effect of chemotherapy on the cancer stem cell fraction varied irrespective of RB1 expression. Our results suggest that patients carrying RB-deficient TNBCs would benefit from gamma-irradiation as well as doxorubicin and methotrexate therapy, but not necessarily from many other anti-neoplastic drugs.

  18. Quantization of Friedmann-Robertson-Walker spacetimes in the presence of a negative cosmological constant and radiation

    SciTech Connect

    Monerat, G.A.; Silva, E.V. Correa; Oliveira-Neto, G.

    2006-02-15

    In the present work, we quantize three Friedmann-Robertson-Walker models in the presence of a negative cosmological constant and radiation. The models differ from each other by the constant curvature of their spatial sections, which may be positive, negative or zero. They give rise to Wheeler-DeWitt equations for the scale factor which have the form of the Schroedinger equation for the quartic anharmonic oscillator. We find their eigenvalues and eigenfunctions by using a method first developed by Chhajlany and Malnev. After that, we use the eigenfunctions in order to construct wave packets for each case and evaluate the time-dependent expectation value of the scale factors, which are found to oscillate between finite maximum and minimum values. Since the expectation values of the scale factors never vanish, we have an initial indication that these models may not have singularities at the quantum level.

  19. Combined exposure to ambient UVB radiation and nitrite negatively affects survival of amphibian early life stages.

    PubMed

    Macías, Guadalupe; Marco, Adolfo; Blaustein, Andrew R

    2007-10-15

    Many aquatic species are sensitive to ambient levels of ultraviolet-B radiation (UVB) and chemical fertilizers. However, recent studies indicate that the interaction among multiple stressors acting simultaneously could be contributing to the population declines of some animal species. Therefore, we tested the potential synergistic effects between ambient levels of UVB and a contaminant, sodium nitrite in the larvae of two amphibian species, the common European toad Bufo bufo and the Iberian green frog Rana perezi. We studied R. perezi from both mountain and coastal populations to examine if populations of the same species varied in their response to stressors in different habitats. Both species were sensitive to the two stressors acting alone, but the interaction between the two stressors caused a multiplicative impact on tadpole survival. For B. bufo, the combination of UVB and nitrite was up to seven times more lethal than mortality for each stressor alone. In a coastal wetland, the combination of UVB and nitrite was four times more toxic for R. perezi than the sum of the effect on mortality for each stressor alone. One mg/L of nitrite killed half the population of R. perezi at Gredos Mountains at day 10 in the absence of UVB. In the presence of UVB, 50% of the tadpoles from the same experiment died at day 7. Similar toxic response were found for R. perezi in two highly contrasted environments suggesting this synergistic interaction can be a widespread phenomenon. The interaction of excess chemical fertilizers and manure with ambient UVB radiation could be contributing to the global decline of some amphibian species. We suggest that potential exposure to UVB radiation be accounted for when assessing water quality criteria regarding nitrite pollution.

  20. A collisional radiative model for caesium and its application to an RF source for negative hydrogen ions

    SciTech Connect

    Wünderlich, D. Wimmer, C.; Friedl, R.

    2015-04-08

    A collisional radiative (CR) model for caesium atoms in low-temperature, low-pressure hydrogen-caesium plasmas is introduced. This model includes the caesium ground state, 14 excited states, the singly charged caesium ion and the negative hydrogen ion. The reaction probabilities needed as input are based on data from the literature, using some scaling and extrapolations. Additionally, new cross sections for electron collision ionization and three-body recombination have been calculated. The relevance of mutual neutralization of positive caesium ions and negative hydrogen ions is highlighted: depending on the densities of the involved particle species, this excitation channel can have a significant influence on the population densities of excited states in the caesium atom. This strong influence is successfully verified by optical emission spectroscopy measurements performed at the IPP prototype negative hydrogen ion source for ITER NBI. As a consequence, population models for caesium in electronegative low-temperature, low-pressure hydrogen-caesium plasmas need to take into account the mutual neutralization process. The present CR model is an example for such models and represents an important prerequisite for deducing the total caesium density in surface production based negative hydrogen ion sources.

  1. A collisional radiative model for caesium and its application to an RF source for negative hydrogen ions

    NASA Astrophysics Data System (ADS)

    Wünderlich, D.; Wimmer, C.; Friedl, R.

    2015-04-01

    A collisional radiative (CR) model for caesium atoms in low-temperature, low-pressure hydrogen-caesium plasmas is introduced. This model includes the caesium ground state, 14 excited states, the singly charged caesium ion and the negative hydrogen ion. The reaction probabilities needed as input are based on data from the literature, using some scaling and extrapolations. Additionally, new cross sections for electron collision ionization and three-body recombination have been calculated. The relevance of mutual neutralization of positive caesium ions and negative hydrogen ions is highlighted: depending on the densities of the involved particle species, this excitation channel can have a significant influence on the population densities of excited states in the caesium atom. This strong influence is successfully verified by optical emission spectroscopy measurements performed at the IPP prototype negative hydrogen ion source for ITER NBI. As a consequence, population models for caesium in electronegative low-temperature, low-pressure hydrogen-caesium plasmas need to take into account the mutual neutralization process. The present CR model is an example for such models and represents an important prerequisite for deducing the total caesium density in surface production based negative hydrogen ion sources.

  2. Kinetics of the nitrogen first negative system excitation by ionising radiation

    SciTech Connect

    Khasenov, M U

    2005-12-31

    The rate constants of N{sub 2}{sup +}(B) quenching by nitrogen and helium and of two- and three-body charge exchange of He{sub 2}{sup +} on H{sub 2}, D{sub 2}, and Kr are measured from luminescence at the 0-0 transition of the first negative system of nitrogen in mixtures of helium and nitrogen with hydrogen, krypton or deuterium excited by alpha particles emitted by {sup 210}Po . (active media)

  3. Negative impacts of ultraviolet-A radiation on antioxidant and oxidative stress biomarkers of African catfish Clarias gariepinus.

    PubMed

    Ibrahim, Ahmed Th A

    2015-07-01

    The present study was carried out to evaluate the ultraviolet-A (UVA) effects on biochemical, oxidative stress and antioxidant changes using aquatic species. The destructive effects of ultraviolet-A radiation on the African Catfish, Clarias gariepinus was revealed in terms of the carbonyl protein (CP), lipid peroxidation (LPO), DNA damage, super oxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PDH), lactate dehydrogenase (LDH), glutathione (GSH) and total antioxidant (TAO) in the gills, kidney, liver, muscles and skin. Also, glucose, total lipid, total protein and cortisol content of fish serums was detected. These parameters can be used as biomarkers to identify the negative effects of UVA radiation (20, 60 and 180 min per day) for 3 days in different tissues of Clarias gariepinus. There was a significant decrease in the activity of SOD, CAT, Gpx, GSH, G6PDH, LDH, and TAO in all of the examined tissues. The pattern of GR activity in UVA exposed groups showed no significant differences compared with the control group. However, CP, LPO and DNA damage were increased significantly with exposure periods in all of the examined tissues. The exposure to different doses of UVA caused hypoglycaemia, hypolipidimia and hypoproteinimia. Cortisol levels showed a significant increase after UV exposure when compared with the control group. In conclusion, UVA exposure with different time periods has been shown to have negative effects on the blood biochemistry, hormonal and antioxidant capacity of Clarias gariepinus tissues.

  4. Nonlinear Cavity and Frequency Comb Radiations Induced by Negative Frequency Field Effects

    NASA Astrophysics Data System (ADS)

    Lourés, Cristian Redondo; Faccio, Daniele; Biancalana, Fabio

    2015-11-01

    Optical Kerr frequency combs (KFCs) are an increasingly important optical metrology tool with applications ranging from ultraprecise spectroscopy to time keeping. KFCs may be generated in compact resonators with extremely high quality factors. Here, we show that the same features that lead to high quality frequency combs in these resonators also lead to an enhancement of nonlinear emissions that may be identified as originating from the presence of a negative frequency (NF) component in the optical spectrum. While the negative frequency component of the spectrum is naturally always present in the real-valued optical field, it is not included in the principal theoretical model used to model nonlinear cavities, i.e., the Lugiato-Lefever equation. We therefore extend these equations in order to include the contribution of NF components and show that the predicted emissions may be studied analytically, in excellent agreement with full numerical simulations. These results are of importance for a variety of fields, such as Bose-Einstein condensates, mode-locked lasers, nonlinear plasmonics, and polaritonics.

  5. Nonlinear Cavity and Frequency Comb Radiations Induced by Negative Frequency Field Effects.

    PubMed

    Lourés, Cristian Redondo; Faccio, Daniele; Biancalana, Fabio

    2015-11-06

    Optical Kerr frequency combs (KFCs) are an increasingly important optical metrology tool with applications ranging from ultraprecise spectroscopy to time keeping. KFCs may be generated in compact resonators with extremely high quality factors. Here, we show that the same features that lead to high quality frequency combs in these resonators also lead to an enhancement of nonlinear emissions that may be identified as originating from the presence of a negative frequency (NF) component in the optical spectrum. While the negative frequency component of the spectrum is naturally always present in the real-valued optical field, it is not included in the principal theoretical model used to model nonlinear cavities, i.e., the Lugiato-Lefever equation. We therefore extend these equations in order to include the contribution of NF components and show that the predicted emissions may be studied analytically, in excellent agreement with full numerical simulations. These results are of importance for a variety of fields, such as Bose-Einstein condensates, mode-locked lasers, nonlinear plasmonics, and polaritonics.

  6. External radiation is associated with limited improvement in overall survival in resected margin-negative stage IIB pancreatic adenocarcinoma.

    PubMed

    Kantor, Olga; Talamonti, Mark S; Lutfi, Waseem; Wang, Chi-Hsiung; Winchester, David J; Marsh, Robert; Prinz, Richard A; Baker, Marshall S

    2016-12-01

    The absolute benefit of adjuvant external beam radiation therapy after a margin-negative resection in early stage pancreatic cancer has not been determined. We queried the National Cancer Data Base for patients with pathologic stage I-II pancreatic adenocarcinoma who underwent operative resection between 2004 and 2012. Multivariate Cox regression adjusted for age, race, comorbidities, facility type, location and volume, type of pancreatectomy, and tumor grade was used to estimate stage-specific survival. A total of 15,966 patients with stage I-II pancreatic adenocarcinoma underwent upfront operative therapy (no neoadjuvant treatment) and had a margin-negative resection during the study period. A total of 835 (5.2%) patients were pathologic stage IA, 1,539 (9.5%) were stage IB, 3,378 (20.9%) were stage IIA, and 10,214 (63.1%) were stage IIB. Chemoradiation utilization increased with increasing stage (22.8% in stage IA vs 39.6% in stage IIB, P < .01). Chemoradiation was more common at low-volume centers (39.0% vs 31.7% at high-volume centers, P < .01) and with younger age (43.3% of patients <70 years old compared to 25.0% ≥70 years old, P < .01). Treatment at a high-volume center was associated with decreased mortality (hazard ratio 0.80-0.89) across all stages. Age ≥70 years old (hazard ratio 1.18-1.29, P < .01) and higher grade (hazard ratio 1.68-2.69, P < .01) were associated with higher risk of mortality at all stages. Chemoradiation was associated with a benefit in median overall survival over chemotherapy alone for stage IIB disease (21.8 months vs 19.5 months, P < .01). Chemoradiation was not associated with a significant benefit in median overall survival for stage IA, IB, or IIA disease (P > .30). Addition of radiation to adjuvant chemotherapy after margin-negative resection of pancreatic adenocarcinoma is associated with a limited survival benefit in patients with pathologic stage IIB disease and should be weighed against its

  7. Surface temperature cooling trends and negative radiative forcing due to land use change toward greenhouse farming in southeastern Spain

    NASA Astrophysics Data System (ADS)

    Campra, Pablo; Garcia, Monica; Canton, Yolanda; Palacios-Orueta, Alicia

    2008-09-01

    Greenhouse horticulture has experienced in recent decades a dramatic spatial expansion in the semiarid province of Almeria, in southeastern (SE) Spain, reaching a continuous area of 26,000 ha in 2007, the widest greenhouse area in the world. A significant surface air temperature trend of -0.3°C decade-1 in this area during the period 1983-2006 is first time reported here. This local cooling trend shows no correlation with Spanish regional and global warming trends. Radiative forcing (RF) is widely used to assess and compare the climate change mechanisms. Surface shortwave RF (SWRF) caused through clearing of pasture land for greenhouse farming development in this area is estimated here. We present the first empirical evidences to support the working hypothesis of the development of a localized forcing created by surface albedo change to explain the differences in temperature trends among stations either inside or far from this agricultural land. SWRF was estimated from satellite-retrieved surface albedo data and calculated shortwave outgoing fluxes associated with either uses of land under typical incoming solar radiation. Outgoing fluxes were calculated from Moderate Resolution Imaging Spectroradiometer (MODIS) surface reflectance data. A difference in mean annual surface albedo of +0.09 was measured comparing greenhouses surface to a typical pasture land. Strong negative forcing associated with land use change was estimated all year round, ranging from -5.0 W m-2 to -34.8 W m-2, with a mean annual value of -19.8 W m-2. According to our data of SWRF and local temperatures trends, recent development of greenhouse horticulture in this area may have masked local warming signals associated to greenhouse gases increase.

  8. HER2-associated radiation resistance of breast cancer stem cells isolated from HER2-negative breast cancer cells

    PubMed Central

    Duru, Nadire; Fan, Ming; Candas, Demet; Menaa, Cheikh; Liu, Hsin-Chen; Nantajit, Danupon; Wen, Yunfei; Xiao, Kai; Eldridge, Angela; Chromy, Brett A.; Li, Shiyong; Spitz, Douglas R.; Lam, Kit S.; Wicha, Max S.; Li, Jian Jian

    2012-01-01

    Purpose To understand the role of HER2-associated signaling network in breast cancer stem cells (BCSCs); using radiation-resistant breast cancer cells and clinical recurrent breast cancers to evaluate HER2-targeted therapy as a tumor eliminating strategy for recurrent HER2−/low breast cancers. Experimental Design HER2-expressing BCSCs (HER2+/CD44+/CD24−/low) were isolated from radiation-treated breast cancer MCF7 cells and in vivo irradiated MCF7 xenograft tumors. Tumor aggressiveness and radiation resistance were analyzed by gap filling, Matrigel invasion, tumor-sphere formation, and clonogenic survival assays. The HER2/CD44 feature was analyzed in 40 primary and recurrent breast cancer specimens. Protein expression profiling in HER2+/CD44+/CD24−/low versus HER2−/CD44+/CD24−/low BCSCs was conducted with 2-D DIGE and HPLC-MS/MS analysis and HER2-mediated signaling network was generated by MetaCore™ program. Results Compared to HER2-negative BCSCs, HER2+/CD44+/CD24−/low cells showed elevated aldehyde dehydrogenase (ALDH) activity and aggressiveness tested by matrigel invasion, tumor sphere formation and in vivo tumorigenesis. The enhanced aggressive phenotype and radioresistance of the HER2+/CD44+/CD24−/low cells were markedly reduced by inhibition of HER2 via siRNA or Herceptin treatments. Clinical breast cancer specimens revealed that cells co-expressing HER2 and CD44 were more frequently detected in recurrent (84.6%) than primary tumors (57.1%). In addition, 2-D DIGE and HPLC-MS/MS of HER2+/CD44+/CD24−/low versus HER2−/CD44+/CD24−/low BCSCs reported a unique HER2-associated protein profile including effectors involved in tumor metastasis, apoptosis, mitochondrial function and DNA repair. A specific feature of HER2-STAT3 network was identified. Conclusion This study provides the evidence that HER2-mediated pro-survival signaling network is responsible for the aggressive phenotype of breast cancer stem cells that could be targeted to control

  9. Omitting radiation therapy in women with triple-negative breast cancer leads to worse breast cancer-specific survival.

    PubMed

    Kindts, I; Buelens, P; Laenen, A; Van Limbergen, E; Janssen, H; Wildiers, H; Weltens, C

    2017-04-01

    To examine locoregional recurrence (LRR) and breast cancer-specific survival (BCSS) after breast-conserving therapy (BCT) or mastectomy (ME) with or without radiation therapy (RT) in triple-negative breast cancer (TNBC). We identified non-metastatic TNBC cases from a single institution database. BCT, ME with RT (ME + RT) and ME only were compared with respect to LRR and BCSS. Cox regression models were used to analyze the association between prognostic factors and outcome. 439 patients fulfilled the inclusion criteria. Median follow-up was 10.2 years (interquartile range 7.9; 12.4 years). Patients in the BCT (n = 239), ME + RT (n = 116) and ME only (n = 84) group differed with respect to age, pT, pN, lymphovascular invasion, lymph node dissection and chemotherapy administration. Ten-year LRR rates were seven percent, three percent and eight percent for the BCT, ME + RT and ME only group, respectively. pN was associated with LRR. In multivariable analysis LRR were significantly lower in the ME + RT group compared to the BCT and the ME only group (p 0.037 and 0.020, respectively). Ten year BCSS was 87%, 84% and 75% for the BCT, ME + RT and ME only group, respectively. pT, pN, lymph node dissection, lymphovascular invasion and the administration of chemotherapy were associated with BCSS. In multivariable analysis BCSS was significantly lower in the ME only group compared to the BCT group and the ME + RT group (p 0.047 and 0.003, respectively). TNBC patients treated with ME without adjuvant RT showed significant lower BCSS compared to patients treated with BCT or ME + RT and significant more LRR compared to ME + RT when corrected for known clinicopathological prognostic factors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Significant Radiation Enhancement Effects by Gold Nanoparticles in Combination with Cisplatin in Triple Negative Breast Cancer Cells and Tumor Xenografts.

    PubMed

    Cui, Lei; Her, Sohyoung; Dunne, Michael; Borst, Gerben R; De Souza, Raquel; Bristow, Robert G; Jaffray, David A; Allen, Christine

    2017-02-01

    Gold nanoparticles (AuNPs) and cisplatin have been explored in concomitant chemoradiotherapy, wherein they elicit their effects by distinct and overlapping mechanisms. Cisplatin is one of the most frequently utilized radiosensitizers in the clinical setting; however, the therapeutic window of cisplatin-aided chemoradiotherapy is limited by its toxicity. The goal of this study was to determine whether AuNPs contribute to improving the treatment response when combined with fractionated cisplatin-based chemoradiation in both in vitro and in vivo models of triple-negative breast cancer (MDA-MB-231(Luc+)). Cellular-targeting AuNPs with receptor-mediated endocytosis (AuNP-RME) in vitro at a noncytotoxic concentration (0.5 mg/ml) or cisplatin at IC25 (12 μM) demonstrated dose enhancement factors (DEFs) of 1.25 and 1.14, respectively; the combination of AuNP-RME and cisplatin resulted in a significant DEF of 1.39 in vitro. Transmission electron microscopy (TEM) images showed effective cellular uptake of AuNPs at tumor sites 24 h after intratumoral infusion. Computed tomography (CT) images demonstrated that the intratumoral levels of gold remained stable up to 120 h after infusion. AuNPs (0.5 mg gold per tumor) demonstrated a radiation enhancement effect that was equivalent to three doses of cisplatin at IC25 (4 mg/kg), but did not induce intrinsic toxicity or increased radiotoxicity. Results from this study suggest that AuNPs are the true radiosensitizer in these settings. Importantly, AuNPs enhance the treatment response when combined with cisplatin-based fractionated chemoradiation. This combination of AuNPs and cisplatin provides a promising approach to improving the therapeutic ratio of fractionated radiotherapy.

  11. Peculiarities of biological action of hadrons of space radiation.

    PubMed

    Akoev, I G; Yurov, S S

    1975-01-01

    Biological investigations in space enable one to make a significant contribution on high-energy hadrons to biological effects under the influence of factors of space flights. Physical and molecular principles of the action of high-energy hadrons are analysed. Genetic and somatic hadron effects produced by the secondary radiation from 70 GeV protons have been studied experimentally. The high biological effectiveness of hadrons, great variability in biological effects, and specifically of their action, are associated with strong interactions of high-energy hadrons. These are the probability of nuclear interaction with any atom nucleus, generation of a great number of secondary particles (among them, probably, highly effective multicharged and heavy nuclei, antiprotons, pi(-)-mesons), and the spatial distribution of secondary particles as a narrow cone with extremely high density of particles in its first part. The secondary radiation generated by high- and superhigh-energy hadrons upon their interaction with the spaceship is likely to be the greatest hazard of radiation to the crew during space flights.

  12. Investigation of Negative Cloud Radiative Forcing over the Indian Subcontinent and Adjacent Oceans During the Summer Monsoon Season Using Satellite Data

    NASA Astrophysics Data System (ADS)

    Thampi, B. V.; Roca, R.

    2011-12-01

    The present study investigates radiative properties of clouds over the Indian subcontinent and nearby oceanic regions (0-25°N, 60-110°E) during the summer monsoon months (June-September) using satellite data. TOA flux data from CERES instrument onboard the NASA Terra platform was used to study the cloud radiative characteristics over this region. Study shows that there exists a unique imbalance between shortwave cloud radiative forcing (SWCRF) and longwave cloud radiative forcing (LWCRF) over this region. Net cloud radiative forcing (NCRF) was found to be negative (of the order of 25-50 W/m2) especially over the northern Bay of Bengal (close to the Myanmar-Thailand coast), northeast Arabian Sea, Western Ghats over Indian land mass as well as over the coastal region of Myanmar and Thailand while it was found to be zero over the equatorial Indian Ocean. Analysis has been carried out to understand the observed spatial inhomogeneity in the NCRF over this region. Analysis of fractional cloud cover shows occurrence of distinctly different cloud types over the negative NCRF regions. Over the Bay of Bengal, high altitude clouds associated with convective regions were found to contribute toward the negative NCRF while middle level clouds found to be more prominent over the Western Ghats and coastal regions of Myanmar and Thailand. A close association between monsoon rainfall activity and SWCRF was observed over the Bay of Bengal during this season. Impact of atmospheric water vapor in modulating the LWCRF over Bay of Bengal is also analyzed.

  13. Cancer of the breast. Radiation therapy.

    PubMed

    Mercado, R; Deutsch, M

    1979-01-01

    There are many questions that have to be answered concerning the role of radiotherapy in the management of primary breast cancer. Hopefully, prospective clinical trials will provide some answers, but more basic research into the biology of breast cancer and the host-tumor relationship will be needed. There are indications that radiotherapy alone, or following minimal extirpative surgery in selected cases, may be as effective for control of breast cancer as conventional mastectomies. The role of radiotherapy following segmental mastectomy, with or without axillary dissection, needs to be clarified. The possibility exists that high LET (linear energy transfer) radiation such as neutron or pi meson beams may provide better local control than conventional radiation. Thus, it may be possible to treat effectively all primary breast cancers with such radiations and obviate the need for any type of mastectomy. It remains to be demonstrated whether adjuvant chemotherapy is as effective as radiotherapy in preventing chest wall and regional node recurrences. If it is not, there may be a place for both adjuvant chemotherapy and radiotherapy in the treatment of operable cancer of the breast. Likewise, effective chemotherapy combined with radiotherapy may increase the local and regional control achieved with radiotherapy alone and make more primary lesions suitable for treatment without mastectomy. Meyer (1970) recently called attention to the leukopenia and cellualr immune deficiency produced by irradiation to the thorax and mediastinum. Further study is necessary to define exactly how much immunosuppression results from radiotherapy, its clinical significance and what can be done to avoid or counter it. If Stjervsward's thesis (1974) concerning the deleterious effects of radiotherapy on survival is correct, then it is of great importance to identify those patients most likely to be adversely affected by radiotherapy. Conversely, it may be possible in the future to identify a

  14. Interaction of wide band gap single crystals with 248 nm excimer laser radiation. XII. The emission of negative atomic ions from alkali halides

    SciTech Connect

    Kimura, Kenichi; Langford, S. C.; Dickinson, J. T.

    2007-12-01

    Many wide band gap materials yield charged and neutral emissions when exposed to sub-band-gap laser radiation at power densities below the threshold for optical breakdown and plume formation. In this work, we report the observation of negative alkali ions from several alkali halides under comparable conditions. We observe no evidence for negative halogen ions, in spite of the high electron affinities of the halogens. Significantly, the positive and negative alkali ions show a high degree of spatial and temporal overlap. A detailed study of all the relevant particle emissions from potassium chloride (KCl) suggests that K{sup -} is formed by the sequential attachment of two electrons to K{sup +}.

  15. [Mitochondria-targeted antioxidant SkQR1 selectively protects MDR-negative cells against ionizing radiation].

    PubMed

    Fetisova, E K; Antoshina, M M; Cherepanynets, V D; Izumov, D S; Kireev, I I; Kireev, R I; Lyamzaev, K G; Riabchenko, N I; Chernyak, B V; Skulachev, V P

    2014-01-01

    Radioprotection appeared to be an important problem of today due to atom energetic development and utilization of radiation material in the industry, science and medicine. It has been shown that mitochondrial targeted antioxidant SkQR1 could attenuate radiation injury of human erythroleukemia K562 cells. Pretreatment with SkQR1 before irradiation decreased DNA double strand breaks formation, diminished the number of chromosomal aberrations and suppressed delayed ROS production. Prevention of oxidative stress and normalization of mitochondrial function by mitochondria-targeted antioxidants may be a potential therapeutic strategy not only against immediate consequences of radiation, but, either against its late consequences such as genomic instability. SkQR1 did not protect against radiation-induced damage the K562 subline with high level of multidrug resistance (MDR) due to SkQR1 extrusion with Pgp 170 MDR pump. We suggest that mitochondria-targeted antioxidants might be used for selective protection of normal cells against radiation-induced damage without interference with radiotherapy of MDR-positive tumors.

  16. Response to Multiple Radiation Doses of Human Colorectal Carcinoma Cells Infected With Recombinant Adenovirus Containing Dominant-Negative Ku70 Fragment

    SciTech Connect

    Urano, Muneyasu; He Fuqiu; Minami, Akiko; Ling, C. Clifton; Li, Gloria C.

    2010-07-01

    Purpose: To investigate the effect of recombinant replication-defective adenovirus containing dominant-negative Ku70 fragment on the response of tumor cells to multiple small radiation doses. Our ultimate goal is to demonstrate the feasibility of using this virus in gene-radiotherapy to enhance the radiation response of tumor cells. Methods and Materials: Human colorectal HCT8 and HT29 carcinoma cells were plated in glass tubes, infected with virus (25 multiplicity of infection), and irradiated with a single dose or zero to five doses of 3 Gy each at 6-h intervals. Hypoxia was induced by flushing with 100% nitrogen gas. The cells were trypsinized 0 or 6 h after the final irradiation, and cell survival was determined by colony formation. The survival data were fitted to linear-quadratic model or exponential line. Results: Virus infection enhanced the radiation response of the HCT8 and HT29 cells. The virus enhancement ratio for single-dose irradiation at a surviving fraction of 0.1 was {approx}1.3 for oxic and hypoxic HCT8 and 1.4 and 1.1 for oxic and hypoxic HT29, respectively. A similar virus enhancement ratio of 1.2-1.3 was observed for both oxic and hypoxic cells irradiated with multiple doses; however, these values were smaller than the values found for dominant-negative Ku70-transfected Rat-1 cells. This difference has been discussed. The oxygen enhancement ratio for HCT8 and HT29 receiving fractionated doses was 1.2 and 2.0, respectively, and virus infection altered them slightly. Conclusion: Infection of recombinant replication-defective adenovirus containing dominant-negative Ku70 fragment enhanced the response of human colorectal cancer cells to single and multiple radiation doses.

  17. Radiation

    NASA Image and Video Library

    Outside the protective cocoon of Earth's atmosphere, the universe is full of harmful radiation. Astronauts who live and work in space are exposed not only to ultraviolet rays but also to space radi...

  18. Focusing of dipole radiation by a negative index chiral layer. 1. A thick layer as compared with the wavelength

    SciTech Connect

    Guzatov, D V; Klimov, V V

    2014-09-30

    We have derived and investigated the analytical expressions for the fields of scattered radiation of an electric dipole source by a chiral (bi-isotropic) layer with arbitrary permittivity and permeability and arbitrary thickness. It is shown that in the negativeindex chiral layer the focus spot of dipole radiation is split due to excitation of right- and left-hand circularly polarised waves. The conditions are found under which the waves with one of the polarisations can be suppressed, which leads to a substantial improvement of the focusing properties of the chiral layer. (metamaterials)

  19. Lack of differences in radiation-induced immunogenicity parameters between HPV-positive and HPV-negative human HNSCC cell lines.

    PubMed

    Schneider, Karolin; Bol, Vanesa; Grégoire, Vincent

    2017-09-12

    Clinical studies indicate that patients with HPV/p16-associated head & neck squamous cell carcinoma (HNSCC) represent a subgroup with a better prognosis and improved response to conventional radiotherapy. Involvement of immune-based factors has been hypothesized. In the present study, we investigated radiation-induced differences in release of damage associated molecular patterns (DAMPs), cytokines and activation of dendritic cells (DCs) in HPV-positive and negative HNSCC cancer cell lines. Calreticulin (CRT) exposure was detected on cancer cell surface. ATP, HMGB1 and cytokines were measured in culture supernatants. Maturation marker CD83 surface exposure was determined on DCs after co-incubation with irradiated tumor cells. There was no increase in DAMPs and cytokine profiles after radiation treatment and no difference between HPV+ and HPV- cell lines. The HPV/p16-positive SCC90 cells showed a trend for increased total CRT, HMGB1, and number of cytokines compared to all other cell lines. None of the irradiated cancer cell lines could affect DC maturation. Radiation treatment did not increase immunogenicity of HNSCC cell lines assessed by membrane CRT, ATP, HMGB1, cytokines production, and by activation of immature DCs. There was no difference between HPV-positive and HPV-negative cell lines. Copyright © 2017. Published by Elsevier B.V.

  20. Adjuvant Radiation Improves Survival in Older Women Following Breast-Conserving Surgery for Estrogen Receptor-Negative Breast Cancer.

    PubMed

    Daugherty, Emily C; Daugherty, Michael R; Bogart, Jeffrey A; Shapiro, Anna

    2016-12-01

    Published prospective trials have questioned the role of post-lumpectomy radiotherapy in older women with early-stage, estrogen receptor-positive (ER(+)) breast cancer. As the population with ER(-) tumors may be at greater risk for relapse, particularly given that endocrine therapy is not effective, we hypothesize the addition of radiation would be of benefit in patients age ≥ 70. The Surveillance, Epidemiology, and End Results database was queried from 1998 to 2011 for patients age ≥ 70 years receiving breast-conserving surgery for T1, ER(-) invasive ductal carcinoma. Patients were separated into 2 cohorts: those treated with and without adjuvant radiotherapy. Chi-square analysis, unpaired t test and Kaplan-Meier log-rank were used to compare patient and tumor characteristics as well as overall and cancer-specific survival between the cohorts. Overall, 3685 patients received radiation and 1493 patients received lumpectomy alone. Patients treated with adjuvant radiation were younger (median age 76 vs. 78 years, P < .0001). Patients who received radiation had improved overall survival, with 5-year survival rates of 81.0% versus 61.7% without radiation (P < .0001). Cancer-specific survival was also improved with radiotherapy, with 5-year cancer-specific survival rates of 93.1% versus 85.0% (P < .0001). This analysis of the SEER database demonstrates that women ages 70 and older treated with lumpectomy and radiotherapy for ER(-), early-stage breast cancer have improved overall survival and breast cancer-specific survival compared with patients treated with lumpectomy alone. This information may help in the decision-making process for this patient population. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Suppression of telomere-binding protein TPP1 resulted in telomere dysfunction and enhanced radiation sensitivity in telomerase-negative osteosarcoma cell line

    SciTech Connect

    Qiang, Weiguang; Wu, Qinqin; Zhou, Fuxiang; Xie, Conghua; Wu, Changping; Zhou, Yunfeng

    2014-03-07

    Highlights: • Down-regulation of TPP1 shortened telomere length in telomerase-negative cells. • Down-regulation of TPP1 induced cell apoptosis in telomerase-negative cells. • Down-regulation of TPP1 increased radiosensitivity in telomerase-negative cells. - Abstract: Mammalian telomeres are protected by the shelterin complex that contains the six core proteins POT1, TPP1, TIN2, TRF1, TRF2 and RAP1. TPP1, formerly known as TINT1, PTOP, and PIP1, is a key factor that regulates telomerase recruitment and activity. In addition to this, TPP1 is required to mediate the shelterin assembly and stabilize telomere. Previous work has found that TPP1 expression was elevated in radioresistant cells and that overexpression of TPP1 led to radioresistance and telomere lengthening in telomerase-positive cells. However, the exact effects and mechanism of TPP1 on radiosensitivity are yet to be precisely defined in the ALT cells. Here we report on the phenotypes of the conditional deletion of TPP1 from the human osteosarcoma U2OS cells using ALT pathway to extend the telomeres.TPP1 deletion resulted in telomere shortening, increased apoptosis and radiation sensitivity enhancement. Together, our findings show that TPP1 plays a vital role in telomere maintenance and protection and establish an intimate relationship between TPP1, telomere and cellular response to ionizing radiation, but likely has the specific mechanism yet to be defined.

  2. Fundamentals of negative refractive index optical trapping: forces and radiation pressures exerted by focused Gaussian beams using the generalized Lorenz-Mie theory.

    PubMed

    Ambrosio, Leonardo A; Hernández-Figueroa, Hugo E

    2010-11-04

    Based on the generalized Lorenz-Mie theory (GLMT), this paper reveals, for the first time in the literature, the principal characteristics of the optical forces and radiation pressure cross-sections exerted on homogeneous, linear, isotropic and spherical hypothetical negative refractive index (NRI) particles under the influence of focused Gaussian beams in the Mie regime. Starting with ray optics considerations, the analysis is then extended through calculating the Mie coefficients and the beam-shape coefficients for incident focused Gaussian beams. Results reveal new and interesting trapping properties which are not observed for commonly positive refractive index particles and, in this way, new potential applications in biomedical optics can be devised.

  3. Radiation pressure cross sections and optical forces over negative refractive index spherical particles by ordinary Bessel beams.

    PubMed

    Ambrosio, Leonardo A; Hernández-Figueroa, Hugo E

    2011-08-01

    When impinged by an arbitrary laser beam, lossless and homogeneous negative refractive index (NRI) spherical particles refract and reflect light in an unusual way, giving rise to different scattered and internal fields when compared to their equivalent positive refractive index particles. In the generalized Lorenz-Mie theory, the scattered fields are dependent upon the Mie scattering coefficients, whose values must reflect the metamaterial behavior of an NRI scatterer, thus leading to new optical properties such as force and torque. In this way, this work is devoted to the analysis of both radial and longitudinal optical forces exerted on lossless and simple NRI particles by zero-order Bessel beams, revealing how the force profiles are changed whenever the refractive index becomes negative.

  4. CONTROL OF LASER RADIATION PARAMETERS: Method for calculating a negative-dispersion resonator-type multilayer mirror

    NASA Astrophysics Data System (ADS)

    Kholokhonova, Polina A.; Erg, G. V.

    2005-11-01

    A method is proposed for the calculation of negative-dispersion mirrors with resonator cavities. The mirror optimisation algorithm combines the capabilities of the gradient method and the random search method. A multilayer mirror structure with a reflectivity R>99.9% and a group delay dispersion of -60±10 fs2 in the 930-1070 nm wavelength range was calculated. The sensitivity of the obtained structure to random variations of layer thicknesses was analysed.

  5. ZRBA1, a Mixed EGFR/DNA Targeting Molecule, Potentiates Radiation Response Through Delayed DNA Damage Repair Process in a Triple Negative Breast Cancer Model.

    PubMed

    Heravi, Mitra; Kumala, Slawomir; Rachid, Zakaria; Jean-Claude, Bertrand J; Radzioch, Danuta; Muanza, Thierry M

    2015-06-01

    ZRBA1 is a combi-molecule designed to induce DNA alkylating lesions and to block epidermal growth factor receptor (EGFR) TK domain. Inasmuch as ZRBA1 downregulates the EGFR TK-mediated antisurvival signaling and induces DNA damage, we postulated that it might be a radiosensitizer. The aim of this study was to further investigate the potentiating effect of ZRBA1 in combination with radiation and to elucidate the possible mechanisms of interaction between these 2 treatment modalities. The triple negative human breast MDA-MB-468 cancer cell line and mouse mammary cancer 4T1 cell line were used in this study. Clonogenic assay, Western blot analysis, and DNA damage analysis were performed at multiple time points after treatment. To confirm our in vitro findings, in vivo tumor growth delay assay was performed. Our results show that a combination of ZRBA1 and radiation increases the radiation sensitivity of both cell lines significantly with a dose enhancement factor of 1.56, induces significant numbers of DNA strand breaks, prolongs higher DNA damage up to 24 hours after treatment, and significantly increases tumor growth delay in a syngeneic mouse model. Our data suggest that the higher efficacy of this combination could be partially due to increased DNA damage and delayed DNA repair process and to the inhibition of EGFR. The encouraging results of this combination demonstrated a significant improvement in treatment efficiency and therefore could be applicable in early clinical trial settings. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Negating the Yearly Eccentricity Magnitude Variation of Super-synchronous Disposal Orbits due to Solar Radiation Pressure

    NASA Astrophysics Data System (ADS)

    Jones, S. L.

    Solar radiation pressure alters satellites' eccentricity by accelerating and decelerating them during each orbit. The accumulated perturbation cancels yearly for geostationary satellites, but meanwhile the perigee radius changes. Disposed satellites must be reorbited higher to compensate, using more fuel. The examined disposal orbit points toward the Sun and uses the satellite's natural eccentricity. This causes the eccentricity vector to only change direction, keeping the perigee radius constant. This thesis verifies this behavior over one year with an analytical derivation and MATLAB simulation, gaining useful insights into its cause. The traditional and proposed disposal orbits are then modeled using NASA's GMAT for more realistic simulations. The proposed orbit's sensitivity to satellite and initialization errors is also examined. Relationships are developed to show these errors' effect on the perigee radius. In conclusion, while this orbit can be used in the short term, margins are necessary to guarantee protection of the geostationary belt.

  7. Comment on 'Quantization of Friedmann-Robertson-Walker spacetimes in the presence of a negative cosmological constant and radiation'

    SciTech Connect

    Amore, Paolo; Aranda, Alfredo; Cervantes, Mayra; Diaz-Cruz, J. L.; Fernandez, Francisco M.

    2007-03-15

    The quantization of the Friedmann-Robertson-Walker spacetime in the presence of a negative cosmological constant was used in a recent paper to conclude that there are solutions that avoid singularities (big bang-big crunch) at the quantum level. We show that a proper study of their model does not indicate that it prevents the occurrence of singularities at the quantum level, in fact the quantum probability of such event is larger than the classical one. Our numerical simulations based on the powerful variational sinc collocation method (VSCM) also show that the precision of the results of that paper is much lower than the 20 significant digits reported by the authors.

  8. Radiation-induced lung metastasis development is MT1-MMP-dependent in a triple-negative breast cancer mouse model.

    PubMed

    Bouchard, Gina; Therriault, Hélène; Geha, Sameh; Bujold, Rachel; Saucier, Caroline; Paquette, Benoit

    2017-02-14

    The prognosis of triple-negative breast cancer (TNBC) is still difficult to establish. Some TNBC benefit from radiotherapy (RT) and are cured, while in other patients metastases appear during the first 3 years after treatment. In this study, an animal model of TNBC was used to determine whether the expression of the cell membrane protease MT1-MMP in cancer cells was associated with radiation-stimulated development of lung metastases. Using invasion chambers, irradiated fibroblasts were used as chemoattractants to assess the invasiveness of TNBC D2A1 cell lines showing downregulated expression of MT1-MMP, which were compared with D2A1-wt (wild-type) and D2A1 shMT1-mock (empty vector) cell lines. In a mouse model, a mammary gland was irradiated followed by the implantation of the downregulated MT1-MMP D2A1, D2A1-wt or D2A1 shMT1-mock cell lines. Migration of D2A1 cells in the mammary gland, number of circulating tumour cells and development of lung metastases were assessed. The reduction of MT1-MMP expression decreased the invasiveness of D2A1 cells and blocked the radiation enhancement of cancer cell invasion. In BALB/c mice, irradiation of the mammary gland has stimulated the invasion of cancer cells, which was associated with a higher number of circulating tumour cells and of lung metastases. These adverse effects of radiation were prevented by downregulating the MT1-MMP. This study shows that the MT1-MMP is necessary for the radiation enhancement of lung metastasis development, and that its expression level and/or localisation could be evaluated as a biomarker for predicting the early recurrence observed in some TNBC patients.

  9. Inhibition of serine palmitoyltransferase delays the onset of radiation-induced pulmonary fibrosis through the negative regulation of sphingosine kinase-1 expression.

    PubMed

    Gorshkova, Irina; Zhou, Tong; Mathew, Biji; Jacobson, Jeffrey R; Takekoshi, Daisuke; Bhattacharya, Palash; Smith, Brett; Aydogan, Bulent; Weichselbaum, Ralph R; Natarajan, Viswanathan; Garcia, Joe G N; Berdyshev, Evgeny V

    2012-08-01

    The enforcement of sphingosine-1-phosphate (S1P) signaling network protects from radiation-induced pneumonitis. We now demonstrate that, in contrast to early postirradiation period, late postirradiation sphingosine kinase-1 (SphK1) and sphingoid base-1-phosphates are associated with radiation-induced pulmonary fibrosis (RIF). Using the mouse model, we demonstrate that RIF is characterized by a marked upregulation of S1P and dihydrosphingosine-1-phosphate (DHS1P) levels in the lung tissue and in circulation accompanied by increased lung SphK1 expression and activity. Inhibition of sphingolipid de novo biosynthesis by targeting serine palmitoyltransferase (SPT) with myriocin reduced radiation-induced pulmonary inflammation and delayed the onset of RIF as evidenced by increased animal lifespan and decreased expression of markers of fibrogenesis, such as collagen and α-smooth muscle actin (α-SMA), in the lung. Long-term inhibition of SPT also decreased radiation-induced SphK activity in the lung and the levels of S1P-DHS1P in the lung tissue and in circulation. In vitro, inhibition or silencing of serine palmitoyltransferase attenuated transforming growth factor-β1 (TGF-β)-induced upregulation of α-SMA through the negative regulation of SphK1 expression in normal human lung fibroblasts. These data demonstrate a novel role for SPT in regulating TGF-β signaling and fibrogenesis that is linked to the regulation of SphK1 expression and S1P-DHS1P formation.

  10. Inhibition of serine palmitoyltransferase delays the onset of radiation-induced pulmonary fibrosis through the negative regulation of sphingosine kinase-1 expression[S

    PubMed Central

    Gorshkova, Irina; Zhou, Tong; Mathew, Biji; Jacobson, Jeffrey R.; Takekoshi, Daisuke; Bhattacharya, Palash; Smith, Brett; Aydogan, Bulent; Weichselbaum, Ralph R.; Natarajan, Viswanathan; Garcia, Joe G. N.; Berdyshev, Evgeny V.

    2012-01-01

    The enforcement of sphingosine-1-phosphate (S1P) signaling network protects from radiation-induced pneumonitis. We now demonstrate that, in contrast to early postirradiation period, late postirradiation sphingosine kinase-1 (SphK1) and sphingoid base-1-phosphates are associated with radiation-induced pulmonary fibrosis (RIF). Using the mouse model, we demonstrate that RIF is characterized by a marked upregulation of S1P and dihydrosphingosine-1-phosphate (DHS1P) levels in the lung tissue and in circulation accompanied by increased lung SphK1 expression and activity. Inhibition of sphingolipid de novo biosynthesis by targeting serine palmitoyltransferase (SPT) with myriocin reduced radiation-induced pulmonary inflammation and delayed the onset of RIF as evidenced by increased animal lifespan and decreased expression of markers of fibrogenesis, such as collagen and α-smooth muscle actin (α-SMA), in the lung. Long-term inhibition of SPT also decreased radiation-induced SphK activity in the lung and the levels of S1P-DHS1P in the lung tissue and in circulation. In vitro, inhibition or silencing of serine palmitoyltransferase attenuated transforming growth factor-β1 (TGF-β)-induced upregulation of α-SMA through the negative regulation of SphK1 expression in normal human lung fibroblasts. These data demonstrate a novel role for SPT in regulating TGF-β signaling and fibrogenesis that is linked to the regulation of SphK1 expression and S1P-DHS1P formation. PMID:22615416

  11. Fundamentals of negative refractive index optical trapping: forces and radiation pressures exerted by focused Gaussian beams using the generalized Lorenz-Mie theory

    PubMed Central

    Ambrosio, Leonardo A.; Hernández-Figueroa, Hugo E.

    2010-01-01

    Based on the generalized Lorenz-Mie theory (GLMT), this paper reveals, for the first time in the literature, the principal characteristics of the optical forces and radiation pressure cross-sections exerted on homogeneous, linear, isotropic and spherical hypothetical negative refractive index (NRI) particles under the influence of focused Gaussian beams in the Mie regime. Starting with ray optics considerations, the analysis is then extended through calculating the Mie coefficients and the beam-shape coefficients for incident focused Gaussian beams. Results reveal new and interesting trapping properties which are not observed for commonly positive refractive index particles and, in this way, new potential applications in biomedical optics can be devised. PMID:21258549

  12. RGD-conjugated mesoporous silica-encapsulated gold nanorods enhance the sensitization of triple-negative breast cancer to megavoltage radiation therapy

    PubMed Central

    Zhao, Ning; Yang, Zhangru; Li, Bingxin; Meng, Jin; Shi, Zeliang; Li, Ping; Fu, Shen

    2016-01-01

    Multifunctional nanoprobes have great potential as effective radiosensitizers and drug carriers. RGD-modified gold nanorods could increase the uptake of nanoparticles via receptor-mediated endocytosis in integrin alphaV beta3-overexpressing breast cancer cells, which could enhance the effects of radiation on tumor cells, leading to further radiosensitization. The purpose of our study was to demonstrate that RGD-conjugated mesoporous silica-encapsulated gold nanorods significantly enhanced the sensitization of triple-negative breast cancer to megavoltage energy. The results indicated that RGD-conjugated mesoporous silica-encapsulated gold nanorod multifunctional nanoprobes could achieve radiosensitization in vitro and in vivo, which suggests the potential translation of this nanotechnology to clinical applications in tumor-targeting and selective therapy. PMID:27822038

  13. RGD-conjugated mesoporous silica-encapsulated gold nanorods enhance the sensitization of triple-negative breast cancer to megavoltage radiation therapy.

    PubMed

    Zhao, Ning; Yang, Zhangru; Li, Bingxin; Meng, Jin; Shi, Zeliang; Li, Ping; Fu, Shen

    Multifunctional nanoprobes have great potential as effective radiosensitizers and drug carriers. RGD-modified gold nanorods could increase the uptake of nanoparticles via receptor-mediated endocytosis in integrin alphaV beta3-overexpressing breast cancer cells, which could enhance the effects of radiation on tumor cells, leading to further radiosensitization. The purpose of our study was to demonstrate that RGD-conjugated mesoporous silica-encapsulated gold nanorods significantly enhanced the sensitization of triple-negative breast cancer to megavoltage energy. The results indicated that RGD-conjugated mesoporous silica-encapsulated gold nanorod multifunctional nanoprobes could achieve radiosensitization in vitro and in vivo, which suggests the potential translation of this nanotechnology to clinical applications in tumor-targeting and selective therapy.

  14. Core-level positive-ion and negative-ion fragmentation of gaseous and condensed HCCl3 using synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Lu, K. T.; Chen, J. M.; Lee, J. M.; Haw, S. C.; Liang, Y. C.; Deng, M. J.

    2011-07-01

    We investigated the dissociation dynamics of positive-ion and negative-ion fragments of gaseous and condensed HCCl3 following photoexcitation of Cl 2p electrons to various resonances. Based on ab initio calculations at levels HF/cc-pVTZ and QCISD/6-311G*, the first doublet structures in Cl L-edge x-ray absorption spectrum of HCCl3 are assigned to transitions from the Cl (2P3/2,1/2) initial states to the 10a1* orbitals. The Cl 2p → 10a1* excitation of HCCl3 induces a significant enhancement of the Cl+ desorption yield in the condensed phase and a small increase in the HCCl+ yield in the gaseous phase. Based on the resonant photoemission of condensed HCCl3, excitations of Cl 2p electrons to valence orbitals decay predominantly via spectator Auger transitions. The kinetic energy distributions of Cl+ ion via the Cl 2p → 10a1* excitation are shifted to higher energy ˜0.2 eV and ˜0.1 eV relative to those via the Cl 2p → 10e* excitation and Cl 2p → shape resonance excitation, respectively. The enhancement of the yields of ionic fragments at specific core-excited resonance states is assisted by a strongly repulsive surface that is directly related to the spectator electrons localized in the antibonding orbitals. The Cl- anion is significantly reinforced in the vicinity of Cl 2p ionization threshold of gaseous HCCl3, mediated by photoelectron recapture through post-collision interaction.

  15. Caffeic Acid Phenethyl Ester Increases Radiosensitivity of Estrogen Receptor-Positive and -Negative Breast Cancer Cells by Prolonging Radiation-Induced DNA Damage

    PubMed Central

    Khoram, Nastaran Masoudi; Bigdeli, Bahareh; Nikoofar, Alireza

    2016-01-01

    Purpose Breast cancer is an important cause of death among women. The development of radioresistance in breast cancer leads to recurrence after radiotherapy. Caffeic acid phenethyl ester (CAPE), a polyphenolic compound of honeybee propolis, is known to have anticancer properties. In this study, we examined whether CAPE enhanced the radiation sensitivity of MDA-MB-231 (estrogen receptor-negative) and T47D (estrogen receptor-positive) cell lines. Methods The cytotoxic effect of CAPE on MDA-MB-231 and T47D breast cancer cells was evaluated by performing an 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide (MTT) assay. To assess clonogenic ability, MDA-MB-231 and T47D cells were treated with CAPE (1 µM) for 72 hours before irradiation, and then, a colony assay was performed. A comet assay was used to determine the number of DNA strand breaks at four different times. Results CAPE decreased the viability of both cell lines in a dose- and time-dependent manner. In the clonogenic assay, pretreatment of cells with CAPE before irradiation significantly reduced the surviving fraction of MDA-MB-231 cells at doses of 6 and 8 Gy. A reduction in the surviving fraction of T47D cells was observed relative to MDA-MB-231 at lower doses of radiation. Additionally, CAPE maintained radiation-induced DNA damage in T47D cells for a longer period than in MDA-MB-231 cells. Conclusion Our results indicate that CAPE impairs DNA damage repair immediately after irradiation. The induction of radiosensitivity by CAPE in radioresistant breast cancer cells may be caused by prolonged DNA damage. PMID:27066092

  16. ZRBA1, a Mixed EGFR/DNA Targeting Molecule, Potentiates Radiation Response Through Delayed DNA Damage Repair Process in a Triple Negative Breast Cancer Model

    SciTech Connect

    Heravi, Mitra; Kumala, Slawomir; Rachid, Zakaria; Jean-Claude, Bertrand J.; Radzioch, Danuta; Muanza, Thierry M.

    2015-06-01

    Purpose: ZRBA1 is a combi-molecule designed to induce DNA alkylating lesions and to block epidermal growth factor receptor (EGFR) TK domain. Inasmuch as ZRBA1 downregulates the EGFR TK-mediated antisurvival signaling and induces DNA damage, we postulated that it might be a radiosensitizer. The aim of this study was to further investigate the potentiating effect of ZRBA1 in combination with radiation and to elucidate the possible mechanisms of interaction between these 2 treatment modalities. Methods and Materials: The triple negative human breast MDA-MB-468 cancer cell line and mouse mammary cancer 4T1 cell line were used in this study. Clonogenic assay, Western blot analysis, and DNA damage analysis were performed at multiple time points after treatment. To confirm our in vitro findings, in vivo tumor growth delay assay was performed. Results: Our results show that a combination of ZRBA1 and radiation increases the radiation sensitivity of both cell lines significantly with a dose enhancement factor of 1.56, induces significant numbers of DNA strand breaks, prolongs higher DNA damage up to 24 hours after treatment, and significantly increases tumor growth delay in a syngeneic mouse model. Conclusions: Our data suggest that the higher efficacy of this combination could be partially due to increased DNA damage and delayed DNA repair process and to the inhibition of EGFR. The encouraging results of this combination demonstrated a significant improvement in treatment efficiency and therefore could be applicable in early clinical trial settings.

  17. Response to Multiple Radiation Doses of Human Colorectal Carcinoma Cells Infected with Recombinant Adenovirus Containing Dominant-Negative Ku70 Fragment

    PubMed Central

    Urano, Muneyasu; He, Fuqiu; Minami, Akiko; Ling, C. Clifton; Li, Gloria C.

    2010-01-01

    Purpose To investigate the effect of recombinant replication-defective adenovirus containing DN(dominant-negative)Ku70 fragment on the response of tumor cells to multiple small radiation doses. Ultimate goal is to demonstrate the feasibility of using this virus in gene-radiotherapy to enhance the radiation response of tumor cells. Materials and Methods Human colorectal HCT8 and HT29 carcinoma cells were plated in glass tubes, infected with virus (25 MOI) and irradiated with single doses or 0-5 doses of 3 Gy with 6 h intervals. Hypoxia was induced by flushing 100% N2. Cells were trypsinized 0 or 6 h after (final) irradiation, and cell survival determined by colony formation. Survival data were fitted to L-Q model or exponential line. Results Virus infection enhanced the radiation response of HCT8 and HT29 cells. Virus enhancement ratio (VER) for single dose irradiation at surviving fraction of 0.1 was ~1.3 for both oxic and hypoxic HCT8, and 1.4 and 1.1 for oxic and hypoxic HT29, respectively. Similar VER of 1.2–1.3 was observed for both oxic and hypoxic cells irradiated with multiple doses but these values were smaller than values found for DNKu70-transfected Rat-1 cells. This difference is discussed. The OERs for HCT8 and HT29 receiving fractionated doses were 1.2 and 2.0, respectively, and virus-infection slightly altered them. Conclusion Infection of recombinant replication-defective adenovirus containing DNKu70 fragment enhanced the response of human colorectal cancer cells to single and multiple doses. PMID:20510198

  18. Outcomes of clinically node-negative breast cancer without axillary dissection: can preserved axilla be safely treated with radiation after a positive sentinel node biopsy?

    PubMed

    Sanuki, Naoko; Takeda, Atsuya; Amemiya, Atsushi; Ofuchi, Toru; Ono, Masashi; Ogata, Haruki; Yamagami, Ryo; Hatayama, Jun; Eriguchi, Takahisa; Kunieda, Etsuo

    2013-02-01

    We analyzed whether axillary nodal irradiation could control clinically node-negative disease, including those patients with a positive sentinel lymph node biopsy (SLNB), most of whom received regional nodal irradiation. We also evaluated toxicity profiles that resulted from nodal irradiation. From 1988 to 2011, 2107 patients with cT1-T2N0M0 breast cancer underwent breast conservation therapy in the absence of axillary dissection: nx group (n = 1548), without any axillary surgery; the sn(-) group (n = 518), with a negative SLNB; and sn(+) group (n = 104), with a positive SLNB. The median follow-up times were 88, 56, and 55 months for the nx, sn(-), and sn(+) groups, respectively. The nx group had more risk factors than did the other 2 groups in terms of age, grade, or T stage. Ninety-eight percent of the sn(-)group received only tangent irradiation, and 100% and 83% of the sn(+) and nx group, respectively, received additional regional nodal irradiation. The 5-year cumulative incidences of axillary failure and regional nodal failure were 34, 3, and 0 (2.7%, 0.7%, and 0%; P = .02, log-rank test) and 57, 4, and 0 (4.4, 1%, and 0; P = .04), respectively. Overall survival rates in 5 years were 96.4%, 98.9%, and 97.6% (P = .03), respectively. Symptomatic but transient radiation pneumonitis developed in 31, 16, and 6 (2.0%, 3.1%, and 5.7%). Mild arm edema was observed in 1, 4, and 0 (0.06%, 0.8%, and 0%) in the nx, sn(-), sn(+) groups, respectively. Treatment without axillary dissection showed excellent outcomes with negligible toxicity for patients with clinically node negative, including those with a positive SLNB. Regional nodal irradiation after a positive SLNB is a reasonable alternative to axillary dissection. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. WE-EF-BRA-09: Microbeam Radiation Therapy Enhances Tumor Drug Uptake of PEGylated Liposomal Doxorubicin (PLD) in a Triple Negative Breast Cancer GEM Model

    SciTech Connect

    Chang, SX; Madden, AJ; Rivera, JN; Santos, CM; Hunter, LM; Darr, DB; Zamboni, WC

    2015-06-15

    Purpose: Overcoming low anti-cancer drug uptake in tumors is a key challenge limiting its clinical use. We propose to enhance the drug delivery using upfront Microbeam Radiation Therapy (MRT). MRT is a preclinical cancer therapy that utilizes microplanar beams to deliver spatially oscillating planes of high and low doses. Animal studies have demonstrated that ultrahigh dose (100s Gy) MRT eradicates tumors without damaging the function of normal tissue exposed to the same radiation. Our previous study indicated that MRT induces intense angiogenesis in tumor rim and surrounding normal tissue 1–2 days post radiation. We hypothesize that the tumor microenvironment modulation induced by MRT may enhance carrier-mediated agent drug delivery to tumors with inherent poor drug uptake. We thus investigated MRT-induced pharmacokinetics (PK) of PEGylated liposomal doxorubicin (PLD), a nano-scale doxorubicin, in T11 genetically engineered mouse model of triple negative breast cancer. Methods: A research irradiator (160kVp, RadSource Technologies) with a customized collimator was used to produce the MRT microbeam of in average 390µm width and 1190µm peak-to-peak distance. The peak dose rate of 1–2Gy/min. Dosimetry is by EBT3 film cross-calibrated with ion chamber at large fields. All mice were administered PLD at 6mg/kg IV x1 at 16h post MRT and sacrificed at 5min, 6h, 24h, and 96h post PLD administration (n=3 or 4 per group). Results: The MRT(28Gy)+PLD group mice had a total doxorubicin tumor concentration (area-under-the concentration-curve, AUC) of 206,040ng/mL•h, 3.71 times the concentration of the PLD-alone group. The MRT(34Gy)+PLD group had a higher mean total doxorubicin concentration in tumor (20,779ng/ml) than the MRT(28Gy)+PLD group (10,665ng/ml). Conclusion: Our preliminary results indicate that microbeam radiation therapy (MRT) can enhance nano-scale anti-cancer drug delivery to tumors approximately 4-fold. The exact working mechanism, the comparison with

  20. Cellular metabolic responses of PET radiotracers to (188)Re radiation in an MCF7 cell line containing dominant-negative mutant p53.

    PubMed

    Cheon, Gi Jeong; Chung, Hye-Kyung; Choi, Jung-A; Lee, Su-Jae; Ahn, Soon-Hyuk; Lee, Tae-Sup; Choi, Chang Woon; Lim, Sang Moo

    2007-05-01

    We investigated the relations between the cell uptakes of metabolic radiotracers and beta-radiation pretreatment using a dominant mutant p53 (p53mt) cell line to evaluate the effects of p53 genes on (18)F labeled positron emission tomography (PET) radiotracer uptakes. pCMV-Neo-Bam (control), which contains a neo-resistance marker, and p53 dominant-negative mutant expression constructs were stably transfected into MCF7 cell line. Cells were plated in 24-well plates at 1.0x10(5) cells for 18 h. Rhenium-188 ((188)Re) (a beta emitter) was added to the medium (3.7, 18.5, 37 MBq) and incubated for 24 h. We performed gamma-counting to determine the cellular uptakes of 2-[(18)F]fluoro-2-deoxy-d-glucose (FDG), o-(2-[(18)F]fluoroethyl)-l-tyrosine (FET) and 2'-[(18)F]fluoro-2'-deoxythymidine (FLT) (370 kBq, 60 min). Cell viabilities were determined by trypan blue staining and flow cytometry. p53mt cells showed 1.5-2-fold higher FDG uptake than wild-type p53 cells in basal condition, and the difference of FDG uptake was greater after (188)Re treatment (P<.01). FET uptake increased with (188)Re dose without a significant difference between p53 statuses. p53mt cells showed lower FLT uptake than wild-type p53 cells in basal condition, and the difference of FLT uptake was greater after (188)Re treatment. By cell viability testing and FACS analysis, p53mt cells showed lower viability and a larger apoptotic fraction (sub-G1) than wild-type p53 cells after (188)Re treatment. We speculate that p53 dysfunction increases glucose and decreases thymidine metabolism in cancer cells and that this may be exaggerated by (188)Re beta-radiation. Our findings suggest that FDG could reflect tumor viability and malignant potential after (188)Re beta-radiation treatment, whereas FLT could be a more useful PET radiotracer for assessing therapeutic response to beta-radiation, especially in cancer cells with an altered function of p53.

  1. Celestial diffuse gamma radiation above 30 MeV observed by SAS-2

    NASA Technical Reports Server (NTRS)

    Fichtel, C. E.; Kniffen, D. A.; Hartman, R. C.

    1973-01-01

    The Small Astronomy Satellite (SAS)-2, launched on November 15, 1972, carried into orbit a 32-deck magnetic-core digitized spark chamber gamma ray telescope to study celestial gamma radiation in the energy range above 30 MeV. In the study of several regions with b sub 2 15 deg, a finite, diffuse flux of gamma rays with a steep energy spectrum in the energy region from 35 to 200 MeV is observed. Representing the energy spectrum by a power law of the form dJ/dE = AE to - alpha power over this energy range, alpha is found along with the integral flux above 100 MeV. Combining this result with existing low energy gamma ray data yields an energy spectrum which is not a simple power law in energy, as in the X-ray region, but which demonstrates first an increase and then a decrease in slope, consistent within uncertainties with that predicted by cosmological theories, including the continuous production of high energy gamma rays primarily from neutral pi mesons throughout the history of the universe.

  2. Carried by History: Cesar Lattes, Nuclear Emulsions, and the Discovery of the Pi-meson

    NASA Astrophysics Data System (ADS)

    Vieira, Cássio Leite; Videira, Antonio Augusto Passos

    2014-03-01

    We analyze the role played by the Brazilian physicist Cesar Lattes (1924-2005) in the historical development of the nuclear emulsion technique and in the co-discovery of the pion. His works influenced and gave impetus to the development of experimental physics in Brazil, the foundation of a national center dedicated to physics research, the beginnings of Brazilian "Big Science," and the inauguration of a long-lasting collaboration between Brazil and Japan in the field of comic ray physics.

  3. Impact of Consolidation Radiation Therapy in Stage III-IV Diffuse Large B-cell Lymphoma With Negative Post-Chemotherapy Radiologic Imaging

    SciTech Connect

    Dorth, Jennifer A.; Prosnitz, Leonard R.; Broadwater, Gloria; Diehl, Louis F.; Beaven, Anne W.; Coleman, R. Edward; Kelsey, Chris R.

    2012-11-01

    Purpose: While consolidation radiation therapy (i.e., RT administered after chemotherapy) is routine treatment for patients with early-stage diffuse large B-cell lymphoma (DLBCL), the role of consolidation RT in stage III-IV DLBCL is controversial. Methods and Materials: Cases of patients with stage III-IV DLBCL treated from 1991 to 2009 at Duke University, who achieved a complete response to chemotherapy were reviewed. Clinical outcomes were calculated using the Kaplan-Meier method and were compared between patients who did and did not receive RT, using the log-rank test. A multivariate analysis was performed using Cox proportional hazards model. Results: Seventy-nine patients were identified. Chemotherapy (median, 6 cycles) consisted of anti-CD20 antibody rituximab combined with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP; 65%); cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP; 22%); or other (13%). Post-chemotherapy imaging consisted of positron emission tomography (PET)/computed tomography (CT) (73%); gallium with CT (14%); or CT only (13%). Consolidation RT (median, 25 Gy) was given to involved sites of disease in 38 (48%) patients. Receipt of consolidation RT was associated with improved in-field control (92% vs. 69%, respectively, p = 0.028) and event-free survival (85% vs. 65%, respectively, p = 0.014) but no difference in overall survival (85% vs. 78%, respectively, p = 0.15) when compared to patients who did not receive consolidation RT. On multivariate analysis, no RT was predictive of increased risk of in-field failure (hazard ratio [HR], 8.01, p = 0.014) and worse event-free survival (HR, 4.3, p = 0.014). Conclusions: Patients with stage III-IV DLBCL who achieve negative post-chemotherapy imaging have improved in-field control and event-free survival with low-dose consolidation RT.

  4. Different physiological responses of cyanobacteria to ultraviolet-B radiation under iron-replete and iron-deficient conditions: Implications for underestimating the negative effects of UV-B radiation.

    PubMed

    Li, Zheng-Ke; Dai, Guo-Zheng; Juneau, Philippe; Qiu, Bao-Sheng

    2017-02-06

    Iron deficiency has been considered one of the main limiting factors of phytoplankton productivity in some aquatic systems including oceans and lakes. Concomitantly, solar ultraviolet-B radiation has been shown to have both deleterious and positive impacts on phytoplankton productivity. However, how iron-deficient cyanobacteria respond to UV-B radiation has been largely overlooked in aquatic systems. In this study, physiological responses of four cyanobacterial strains (Microcystis and Synechococcus), which are widely distributed in freshwater or marine systems, were investigated under different UV-B irradiances and iron conditions. The growth, photosynthetic pigment composition, photosynthetic activity, and nonphotochemical quenching of the different cyanobacterial strains were drastically altered by enhanced UV-B radiation under iron-deficient conditions, but were less affected under iron-replete conditions. Intracellular reactive oxygen species (ROS) and iron content increased and decreased, respectively, with increased UV-B radiation under iron-deficient conditions for both Microcystis aeruginosa FACHB 912 and Synechococcus sp. WH8102. On the contrary, intracellular ROS and iron content of these two strains remained constant and increased, respectively, with increased UV-B radiation under iron-replete conditions. These results indicate that iron-deficient cyanobacteria are more susceptible to enhanced UV-B radiation. Therefore, UV-B radiation probably plays an important role in influencing primary productivity in iron-deficient aquatic systems, suggesting that its effects on the phytoplankton productivity may be underestimated in iron-deficient regions around the world.

  5. A Combination of Podophyllotoxin and Rutin Attenuates Radiation Induced Gastrointestinal Injury by Negatively Regulating NF-κB/p53 Signaling in Lethally Irradiated Mice

    PubMed Central

    Kalita, Bhargab; Ranjan, Rajiv; Singh, Abhinav; Yashavarddhan, M. H.; Bajaj, Sania; Gupta, Manju Lata

    2016-01-01

    Development of an effective radio protector to minimise radiation-inflicted damages have largely failed owing to inherent toxicity of most of the agents examined so far. This study is centred towards delivering protection to lethally irradiated mice by pre-administration of a safe formulation G-003M (combination of podophyllotoxin and rutin) majorly through regulation of inflammatory and cell death pathways in mice. Single intramuscular dose of G-003M injected 60 min prior to 9 Gy exposure rescued 89% of whole body lethally irradiated C57BL/6J mice. Studies have revealed reduction in radiation induced reactive oxygen species (ROS), nitric oxide (NO) generation, prostaglandin E2 (PGE2) levels and intestinal apoptosis in G-003M pre-treated mice intestine. Restricted nuclear translocation of redox-sensitive Nuclear factor-κB (NF-κB) and subsequent downregulation of cyclo-oxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS; EC 1.14.13.39) and tumor necrosis factor (TNF-α) levels demonstrated the anti-inflammatory effect that G-003M exerts. Support to early hematopoietic recovery was exhibited through G-003M mediated induction of granulocyte colony stimulating factor (G-CSF) and interleukin (IL-6) levels in lethally irradiated mice. Considerable attenuation in radiation induced morphological damage to the intestinal villi, crypts and mucosal layers was observed in G-003M pre-treated mice. Additionally, our formulation did not reduce the sensitivity of tumor tissue to radiation. Altogether, these results suggest that G-003M ameliorates the deleterious effects of radiation exposure by minimising ROS and NO generation and effectively regulating inflammatory and cell death pathways. Mechanism of protection elucidated in the current study demonstrates that G-003M can be used as a safe and effective radio protective agent in radiotherapy for human application. PMID:28036347

  6. A Combination of Podophyllotoxin and Rutin Attenuates Radiation Induced Gastrointestinal Injury by Negatively Regulating NF-κB/p53 Signaling in Lethally Irradiated Mice.

    PubMed

    Kalita, Bhargab; Ranjan, Rajiv; Singh, Abhinav; Yashavarddhan, M H; Bajaj, Sania; Gupta, Manju Lata

    2016-01-01

    Development of an effective radio protector to minimise radiation-inflicted damages have largely failed owing to inherent toxicity of most of the agents examined so far. This study is centred towards delivering protection to lethally irradiated mice by pre-administration of a safe formulation G-003M (combination of podophyllotoxin and rutin) majorly through regulation of inflammatory and cell death pathways in mice. Single intramuscular dose of G-003M injected 60 min prior to 9 Gy exposure rescued 89% of whole body lethally irradiated C57BL/6J mice. Studies have revealed reduction in radiation induced reactive oxygen species (ROS), nitric oxide (NO) generation, prostaglandin E2 (PGE2) levels and intestinal apoptosis in G-003M pre-treated mice intestine. Restricted nuclear translocation of redox-sensitive Nuclear factor-κB (NF-κB) and subsequent downregulation of cyclo-oxygenase 2 (COX-2), inducible nitric oxide synthase (iNOS; EC 1.14.13.39) and tumor necrosis factor (TNF-α) levels demonstrated the anti-inflammatory effect that G-003M exerts. Support to early hematopoietic recovery was exhibited through G-003M mediated induction of granulocyte colony stimulating factor (G-CSF) and interleukin (IL-6) levels in lethally irradiated mice. Considerable attenuation in radiation induced morphological damage to the intestinal villi, crypts and mucosal layers was observed in G-003M pre-treated mice. Additionally, our formulation did not reduce the sensitivity of tumor tissue to radiation. Altogether, these results suggest that G-003M ameliorates the deleterious effects of radiation exposure by minimising ROS and NO generation and effectively regulating inflammatory and cell death pathways. Mechanism of protection elucidated in the current study demonstrates that G-003M can be used as a safe and effective radio protective agent in radiotherapy for human application.

  7. Thai Negation.

    ERIC Educational Resources Information Center

    Alam, Samsul

    A study analyzed the structure of negative sentences in the Thai language, based on data gathered from two native speakers. It is shown that the Thai negative marker generally occurs between the noun phrase (subject) and the verb phrase in simple active sentences and in passive sentences. Negation of noun phrases is also allowed in Thai, with a…

  8. Fibulin-3 negatively regulates ALDH1 via c-MET suppression and increases γ-radiation-induced sensitivity in some pancreatic cancer cell lines

    SciTech Connect

    Kim, In-Gyu; Lee, Jae-Ha; Kim, Seo-Yoen; Kim, Jeong-Yul; Cho, Eun-Wie

    2014-11-21

    Highlights: • FBLN-3 gene was poorly expressed in some pancreatic cancer lines. • FBLN-3 promoter region was highly methylated in some pancreatic cancer cell lines. • FBLN-3 inhibited c-MET activation and expression and reduced cellular level of ALDH1. • FBLN-3/c-Met/ALDH1 axis modulates stemness and EMT in pancreatic cancer cells. - Abstract: Fibulin-3 (FBLN-3) has been postulated to be either a tumor suppressor or promoter depending on the cell type, and hypermethylation of the FBLN-3 promoter is often associated with human disease, especially cancer. We report that the promoter region of the FBLN-3 was significantly methylated (>95%) in some pancreatic cancer cell lines and thus FBLN-3 was poorly expressed in pancreatic cancer cell lines such as AsPC-1 and MiaPaCa-2. FBLN-3 overexpression significantly down-regulated the cellular level of c-MET and inhibited hepatocyte growth factor-induced c-MET activation, which were closely associated with γ-radiation resistance of cancer cells. Moreover, we also showed that c-MET suppression or inactivation decreased the cellular level of ALDH1 isozymes (ALDH1A1 or ALDH1A3), which serve as cancer stem cell markers, and subsequently induced inhibition of cell growth in pancreatic cancer cells. Therefore, forced overexpression of FBLN-3 sensitized cells to cytotoxic agents such as γ-radiation and strongly inhibited the stemness and epithelial to mesenchymal transition (EMT) property of pancreatic cancer cells. On the other hand, if FBLN3 was suppressed in FBLN-3-expressing BxPC3 cells, the results were opposite. This study provides the first demonstration that the FBLN-3/c-MET/ALDH1 axis in pancreatic cancer cells partially modulates stemness and EMT as well as sensitization of cells to the detrimental effects of γ-radiation.

  9. High Radiation Dose May Reduce the Negative Effect of Large Gross Tumor Volume in Patients With Medically Inoperable Early-Stage Non-Small Cell Lung Cancer

    SciTech Connect

    Zhao Lujun; West, Brady T.; Hayman, James A.; Lyons, Susan; Cease, Kemp; Kong, F.-M. . E-mail: Fengkong@med.umich.edu

    2007-05-01

    Purpose: To determine whether the effect of radiation dose varies with gross tumor volume (GTV) in patients with stage I/II non-small cell lung cancer (NSCLC). Methods and Materials: Included in the study were 114 consecutive patients with medically inoperable stage I/II NSCLC treated with three-dimensional conformal radiotherapy between 1992 and 2004. The median biologic equivalent dose (BED) was 79.2 Gy (range, 58.2-124.5 Gy). The median GTV was 51.8 cm{sup 3} (range, 2.1-727.8 cm{sup 3}). The primary endpoint was overall survival (OS). Kaplan-Meier estimation and Cox regression models were used for survival analyses. Results: Multivariate analysis showed that there was a significant interaction between radiation dose and GTV (p < 0.001). In patients with BED {<=}79.2 Gy (n = 68), the OS medians for patients with GTV >51.8 cm{sup 3} and {<=}51.8 cm{sup 3} were 18.2 and 23.9 months, respectively (p 0.015). If BED was >79.2 Gy (n = 46), no significant difference was found between GTV groups (p = 0.681). For patients with GTV >51.8 cm{sup 3} (n = 45), the OS medians in those with BED >79.2 Gy and {<=}79.2 Gy were 30.4 and 18.2 months, respectively (p < 0.001). If GTV was {<=}51.8 cm{sup 3} (n = 45), the difference was no longer significant (p = 0.577). Conclusion: High-dose radiation is more important for patients with larger tumors and may be effective in reducing the adverse outcome associated with large GTV. Further prospective studies are needed to confirm this finding.

  10. Weekly chemotherapy with radiation versus high-dose cisplatin with radiation as organ preservation for patients with HPV-positive and HPV-negative locally advanced squamous cell carcinoma of the oropharynx.

    PubMed

    Dobrosotskaya, Irina Y; Bellile, Emily; Spector, Matthew E; Kumar, Bhavna; Feng, Felix; Eisbruch, Avraham; Wolf, Gregory T; Prince, Mark E P; Moyer, Jeffrey S; Teknos, Theodoros; Chepeha, Douglas B; Walline, Heather M; McHugh, Jonathan B; Cordell, Kitrina G; Ward, P Daniel; Byrd, Serena; Maxwell, Jessica H; Urba, Susan; Bradford, Carol R; Carey, Thomas E; Worden, Francis P

    2014-05-01

    Optimal treatment for locally advanced squamous cell carcinoma of the oropharynx (SCCOP) is not well defined. Here we retrospectively compare survival and toxicities from 2 different organ preservation protocols. The matched dataset consisted of 35 patients from each trial matched for age, stage, smoking, and tumor human papillomavirus (HPV) status. Patients in the University of Michigan Cancer Center (UMCC) trial 9921 were treated with induction chemotherapy (IC) followed by high-dose cisplatin and radiation in responders or surgery in nonresponders. Patients in the UMCC trial 0221 were treated with weekly carboplatin and paclitaxel and radiation. Survival was comparable for both studies and did not differ significantly across each trial after stratifying by HPV status. Grade 3 and 4 toxicities were more frequent in UMCC 9921. At 6 months posttreatment, gastrostomy tube (G-tube) dependence was not statistically different. These data suggest that survival outcomes in patients with locally advanced SCCOP are not compromised with weekly chemotherapy and radiation therapy, and such treatment is generally more tolerable. Copyright © 2013 Wiley Periodicals, Inc.

  11. Prognostic Value of Molecular Subtypes, Ki67 Expression and Impact of Postmastectomy Radiation Therapy in Breast Cancer Patients With Negative Lymph Nodes After Mastectomy

    SciTech Connect

    Selz, Jessica; Stevens, Denise; Jouanneau, Ludivine; Labib, Alain; Le Scodan, Romuald

    2012-12-01

    Purpose: To determine whether Ki67 expression and breast cancer subtypes could predict locoregional recurrence (LRR) and influence the postmastectomy radiotherapy (PMRT) decision in breast cancer (BC) patients with pathologic negative lymph nodes (pN0) after modified radical mastectomy (MRM). Methods and Materials: A total of 699 BC patients with pN0 status after MRM, treated between 2001 and 2008, were identified from a prospective database in a single institution. Tumors were classified by intrinsic molecular subtype as luminal A or B, HER2+, and triple-negative (TN) using estrogen, progesterone, and HER2 receptors. Multivariate Cox analysis was used to determine the risk of LRR associated with intrinsic subtypes and Ki67 expression, adjusting for known prognostic factors. Results: At a median follow-up of 56 months, 17 patients developed LRR. Five-year LRR-free survival and overall survival in the entire population were 97%, and 94.7%, respectively, with no difference between the PMRT (n=191) and no-PMRT (n=508) subgroups. No constructed subtype was associated with an increased risk of LRR. Ki67 >20% was the only independent prognostic factor associated with increased LRR (hazard ratio, 4.18; 95% CI, 1.11-15.77; P<.0215). However, PMRT was not associated with better locoregional control in patients with proliferative tumors. Conclusions: Ki67 expression but not molecular subtypes are predictors of locoregional recurrence in breast cancer patients with negative lymph nodes after MRM. The benefit of adjuvant RT in patients with proliferative tumors should be further investigated in prospective studies.

  12. VX-970, Cisplatin, and Radiation Therapy in Treating Patients With Locally Advanced HPV-Negative Head and Neck Squamous Cell Carcinoma

    ClinicalTrials.gov

    2017-09-25

    Head and Neck Squamous Cell Carcinoma; Human Papillomavirus Negative; Stage III Nasal Cavity and Paranasal Sinus Squamous Cell Carcinoma AJCC v6 and v7; Stage III Oropharyngeal Squamous Cell Carcinoma AJCC v7; Stage IV Nasal Cavity and Paranasal Sinus Squamous Cell Carcinoma AJCC v7; Stage IV Oropharyngeal Squamous Cell Carcinoma AJCC v7; Stage IVA Nasal Cavity and Paranasal Sinus Squamous Cell Carcinoma AJCC v7; Stage IVA Oropharyngeal Squamous Cell Carcinoma AJCC v7; Stage IVB Nasal Cavity and Paranasal Sinus Squamous Cell Carcinoma AJCC v7; Stage IVB Oropharyngeal Squamous Cell Carcinoma AJCC v7; Stage IVC Nasal Cavity and Paranasal Sinus Squamous Cell Carcinoma AJCC v7; Stage IVC Oropharyngeal Squamous Cell Carcinoma AJCC v7

  13. Flexible delivery of Er:YAG radiation at 2.94 µm with negative curvature silica glass fibers: a new solution for minimally invasive surgical procedures

    PubMed Central

    Urich, A.; Maier, R. R. J.; Yu, Fei; Knight, J. C.; Hand, D. P.; Shephard, J. D.

    2012-01-01

    We present the delivery of high energy microsecond pulses through a hollow-core negative-curvature fiber at 2.94 µm. The energy densities delivered far exceed those required for biological tissue manipulation and are of the order of 2300 J/cm2. Tissue ablation was demonstrated on hard and soft tissue in dry and aqueous conditions with no detrimental effects to the fiber or catastrophic damage to the end facets. The energy is guided in a well confined single mode allowing for a small and controllable focused spot delivered flexibly to the point of operation. Hence, a mechanically and chemically robust alternative to the existing Er:YAG delivery systems is proposed which paves the way for new routes for minimally invasive surgical laser procedures. PMID:23413120

  14. Need for High Radiation Dose (>=70 Gy) in Early Postoperative Irradiation After Radical Prostatectomy: A Single-Institution Analysis of 334 High-Risk, Node-Negative Patients

    SciTech Connect

    Cozzarini, Cesare; Montorsi, Francesco; Fiorino, Claudio; Alongi, Filippo; Bolognesi, Angelo; Da Pozzo, Luigi Filippo; Guazzoni, Giorgio; Freschi, Massimo; Roscigno, Marco; Scattoni, Vincenzo; Rigatti, Patrizio; Di Muzio, Nadia

    2009-11-15

    Purpose: To determine the clinical benefit of high-dose early adjuvant radiotherapy (EART) in high-risk prostate cancer (hrCaP) patients submitted to radical retropubic prostatectomy plus pelvic lymphadenectomy. Patients and Methods: The clinical outcome of 334 hrCaP (pT3-4 and/or positive resection margins) node-negative patients submitted to radical retropubic prostatectomy plus pelvic lymphadenectomy before 2004 was analyzed according to the EART dose delivered to the prostatic bed, <70.2 Gy (lower dose, median 66.6 Gy, n = 153) or >=70.2 Gy (median 70.2 Gy, n = 181). Results: The two groups were comparable except for a significant difference in terms of median follow-up (10 vs. 7 years, respectively) owing to the gradual increase of EART doses over time. Nevertheless, median time to prostate-specific antigen (PSA) failure was almost identical, 38 and 36 months, respectively. At univariate analysis, both 5-year biochemical relapse-free survival (bRFS) and disease-free survival (DFS) were significantly higher (83% vs. 71% [p = 0.001] and 94% vs. 88% [p = 0.005], respectively) in the HD group. Multivariate analysis confirmed EART dose >=70 Gy to be independently related to both bRFS (hazard ratio 2.5, p = 0.04) and DFS (hazard ratio 3.6, p = 0.004). Similar results were obtained after the exclusion of patients receiving any androgen deprivation. After grouping the hormone-naive patients by postoperative PSA level the statistically significant impact of high-dose EART on both 5-year bRFS and DFS was maintained only for those with undetectable values, possibly owing to micrometastatic disease outside the irradiated area in case of detectable postoperative PSA values. Conclusion: This series provides strong support for the use of EART doses >=70 Gy after radical retropubic prostatectomy in hrCaP patients with undetectable postoperative PSA levels.

  15. Negative Certainty

    ERIC Educational Resources Information Center

    Ariso, José María

    2017-01-01

    The definitions of "negative knowledge" and the studies in this regard published to date have not considered the categorial distinction Wittgenstein established between knowledge and certainty. Hence, the important role that certainty, despite its omission, should have in these definitions and studies has not yet been shown. In this…

  16. Negative Certainty

    ERIC Educational Resources Information Center

    Ariso, José María

    2017-01-01

    The definitions of "negative knowledge" and the studies in this regard published to date have not considered the categorial distinction Wittgenstein established between knowledge and certainty. Hence, the important role that certainty, despite its omission, should have in these definitions and studies has not yet been shown. In this…

  17. Negative Numbers

    ERIC Educational Resources Information Center

    Galbraith, Mary J.

    1974-01-01

    Examination of models for representing integers demonstrates that formal operational thought is required for establishing the operations on integers. Advocated is the use of many models for introducing negative numbers but, apart from addition, it is recommended that operations on integers be delayed until the formal operations stage. (JP)

  18. Multimodality functional imaging using DW-MRI and 18F-FDG-PET/CT during radiation therapy for human papillomavirus negative head and neck squamous cell carcinoma: Meixoeiro Hospital of Vigo Experience

    PubMed Central

    Aramburu Núñez, David; Lopez Medina, Antonio; Mera Iglesias, Moisés; Salvador Gomez, Francisco; Dave, Abhay; Hatzoglou, Vaios; Paudyal, Ramesh; Calzado, Alfonso; Deasy, Joseph O; Shukla-Dave, Amita; Muñoz, Victor M

    2017-01-01

    AIM To noninvasively investigate tumor cellularity measured using diffusion-weighted magnetic resonance imaging (DW-MRI) and glucose metabolism measured by 18F-labeled fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) during radiation therapy (RT) for human papillomavirus negative (HPV-) head and neck squamous cell carcinoma (HNSCC). METHODS In this prospective study, 6 HPV- HNSCC patients underwent a total of 34 multimodality imaging examinations DW-MRI at 1.5 T Philips MRI scanner [(n = 24) pre-, during- (2-3 wk), and post-treatment (Tx), and 18F-FDG PET/CT pre- and post-Tx (n = 10)]. All patients received RT. Monoexponential modeling of the DW-MRI data yielded the imaging metric apparent diffusion coefficient (ADC) and the mean of standardized uptake value (SUV) was measured from 18F-FDG PET uptake. All patients had a clinical follow-up as the standard of care and survival status was documented at 1 year. RESULTS There was a strong negative correlation between the mean of pretreatment ADC (ρ = -0.67, P = 0.01) and the pretreatment 18F-FDG PET SUV. The percentage (%) change in delta (∆) ADC for primary tumors and neck nodal metastases between pre- and Wk2-3 Tx were as follows: 75.4% and 61.6%, respectively, for the patient with no evidence of disease, 27.5% and 32.7%, respectively, for those patients who were alive with disease, and 26.9% and 7.31%, respectively, for those who were dead with disease. CONCLUSION These results are preliminary in nature and are indicative, and not definitive, trends rendered by the imaging metrics due to the small sample size of HPV- HNSCC patients in a Meixoeiro Hospital of Vigo Experience. PMID:28144403

  19. Multimodality functional imaging using DW-MRI and (18)F-FDG-PET/CT during radiation therapy for human papillomavirus negative head and neck squamous cell carcinoma: Meixoeiro Hospital of Vigo Experience.

    PubMed

    Aramburu Núñez, David; Lopez Medina, Antonio; Mera Iglesias, Moisés; Salvador Gomez, Francisco; Dave, Abhay; Hatzoglou, Vaios; Paudyal, Ramesh; Calzado, Alfonso; Deasy, Joseph O; Shukla-Dave, Amita; Muñoz, Victor M

    2017-01-28

    To noninvasively investigate tumor cellularity measured using diffusion-weighted magnetic resonance imaging (DW-MRI) and glucose metabolism measured by (18)F-labeled fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG-PET/CT) during radiation therapy (RT) for human papillomavirus negative (HPV-) head and neck squamous cell carcinoma (HNSCC). In this prospective study, 6 HPV- HNSCC patients underwent a total of 34 multimodality imaging examinations DW-MRI at 1.5 T Philips MRI scanner [(n = 24) pre-, during- (2-3 wk), and post-treatment (Tx), and (18)F-FDG PET/CT pre- and post-Tx (n = 10)]. All patients received RT. Monoexponential modeling of the DW-MRI data yielded the imaging metric apparent diffusion coefficient (ADC) and the mean of standardized uptake value (SUV) was measured from (18)F-FDG PET uptake. All patients had a clinical follow-up as the standard of care and survival status was documented at 1 year. There was a strong negative correlation between the mean of pretreatment ADC (ρ = -0.67, P = 0.01) and the pretreatment (18)F-FDG PET SUV. The percentage (%) change in delta (∆) ADC for primary tumors and neck nodal metastases between pre- and Wk2-3 Tx were as follows: 75.4% and 61.6%, respectively, for the patient with no evidence of disease, 27.5% and 32.7%, respectively, for those patients who were alive with disease, and 26.9% and 7.31%, respectively, for those who were dead with disease. These results are preliminary in nature and are indicative, and not definitive, trends rendered by the imaging metrics due to the small sample size of HPV- HNSCC patients in a Meixoeiro Hospital of Vigo Experience.

  20. Electromagnetic radiation detector

    DOEpatents

    Benson, Jay L.; Hansen, Gordon J.

    1976-01-01

    An electromagnetic radiation detector including a collimating window, a cathode member having a photoelectric emissive material surface angularly disposed to said window whereby radiation is impinged thereon at acute angles, an anode, separated from the cathode member by an evacuated space, for collecting photoelectrons emitted from the emissive cathode surface, and a negatively biased, high transmissive grid disposed between the cathode member and anode.

  1. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. BEVATRON SHIELDING - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  2. Combination of the novel histone deacetylase inhibitor YCW1 and radiation induces autophagic cell death through the downregulation of BNIP3 in triple-negative breast cancer cells in vitro and in an orthotopic mouse model.

    PubMed

    Chiu, Hui-Wen; Yeh, Ya-Ling; Wang, Yi-Ching; Huang, Wei-Jan; Ho, Sheng-Yow; Lin, Pinpin; Wang, Ying-Jan

    2016-06-10

    Triple-negative breast cancer (TNBC) is the most aggressive and invasive of the breast cancer subtypes. TNBC is a challenging disease that lacks targets for treatment. Histone deacetylase inhibitors (HDACi) are a group of targeted anticancer agents that enhance radiosensitivity. Bcl-2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) is a member of the Bcl-2 subfamily. BNIP3 is not found in normal breast tissue but is up-regulated in breast cancer. In the present study, we investigated the anti-cancer effects of a newly developed HDACi, YCW1, combined with ionizing radiation (IR) in TNBC in vitro and in an orthotopic mouse model. Furthermore, we examined the relationship between autophagy and BNIP3. Trypan blue exclusion was used to investigate the viability of 4 T1 (a mouse TNBC cell line) and MDA-MB-231 cells (a human TNBC cell line) following combined YCW1 and IR treatment. Flow cytometry was used to determine apoptosis and autophagy. The expression levels of BNIP3, endoplasmic reticulum (ER) stress- and autophagic-related proteins were measured using western blot analysis. An orthotopic mouse model was used to investigate the in vivo effects of YCW1 and IR alone and in combination. Tumor volumes were monitored using a bioluminescence-based IVIS Imaging System 200. We found that YCW1 significantly enhanced toxicity in 4 T1 cells compared with suberoylanilide hydroxamic acid (SAHA), which was the first HDACi approved by the Food and Drug Administration for clinical use in cancer patients. The combined treatment of YCW1 and IR enhanced cytotoxicity by inducing ER stress and increasing autophagy induction. Additionally, the combined treatment caused autophagic flux and autophagic cell death. Furthermore, the expression level of BNIP3 was significantly decreased in cells following combined treatment. The downregulation of BNIP3 led to a significant increase in autophagy and cytotoxicity. The combined anti-tumor effects of YCW1 and IR were also observed

  3. Radiation Protection

    MedlinePlus

    ... EPA United States Environmental Protection Agency Search Search Radiation Protection Share Facebook Twitter Google+ Pinterest Contact Us Radiation Protection Document Library View and download EPA radiation ...

  4. Radiation sickness

    MedlinePlus

    ... to determine the amount of radiation exposure from nuclear accidents, the best signs of the severity of the ... doses of radiation, such as radiation from a nuclear power plant accident Exposure to excessive radiation for medical treatments

  5. Radiation enteritis

    MedlinePlus

    Radiation enteropathy; Radiation-induced small bowel injury; Post-radiation enteritis ... Radiation therapy uses high-powered x-rays, particles, or radioactive seeds to kill cancer cells. The therapy ...

  6. Radiation dosimetry.

    PubMed Central

    Cameron, J

    1991-01-01

    This article summarizes the basic facts about the measurement of ionizing radiation, usually referred to as radiation dosimetry. The article defines the common radiation quantities and units; gives typical levels of natural radiation and medical exposures; and describes the most important biological effects of radiation and the methods used to measure radiation. Finally, a proposal is made for a new radiation risk unit to make radiation risks more understandable to nonspecialists. PMID:2040250

  7. Dose from slow negative muons.

    PubMed

    Siiskonen, T

    2008-01-01

    Conversion coefficients from fluence to ambient dose equivalent, from fluence to maximum dose equivalent and quality factors for slow negative muons are examined in detail. Negative muons, when stopped, produce energetic photons, electrons and a variety of high-LET particles. Contribution from each particle type to the dose equivalent is calculated. The results show that for the high-LET particles the details of energy spectra and decay yields are important for accurate dose estimates. For slow negative muons the ambient dose equivalent does not always yield a conservative estimate for the protection quantities. Especially, the skin equivalent dose is strongly underestimated if the radiation-weighting factor of unity for slow muons is used. Comparisons to earlier studies are presented.

  8. On Multiplying Negative Numbers.

    ERIC Educational Resources Information Center

    Crowley, Mary L.; Dunn, Kenneth A.

    1985-01-01

    Comments on the history of negative numbers, some methods that can be used to introduce the multiplication of negative numbers to students, and an explanation of why the product of two negative numbers is a positive number are included. (MNS)

  9. Radiation Therapy

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Radiation Therapy KidsHealth > For Teens > Radiation Therapy Print A ... how to cope with side effects. What Is Radiation Therapy? Cancer is a disease that causes cells ...

  10. Radiation Therapy

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Radiation Therapy KidsHealth > For Teens > Radiation Therapy A A ... how to cope with side effects. What Is Radiation Therapy? Cancer is a disease that causes cells ...

  11. Radiation Therapy

    MedlinePlus

    Radiation therapy is a cancer treatment. It uses high doses of radiation to kill cancer cells and stop them from ... half of all cancer patients receive it. The radiation may be external, from special machines, or internal, ...

  12. Negative illumination thermoradiative solar cell.

    PubMed

    Liao, Tianjun; Zhang, Xin; Chen, Xiaohang; Lin, Bihong; Chen, Jincan

    2017-08-15

    The negative illumination thermoradiative solar cell (NITSC) consisting of a concentrator, an absorber, and a thermoradiative cell (TRC) is established, where the radiation and reflection losses from the absorber to the environment and the radiation loss from the TRC to the environment are taken into consideration. The power output and overall efficiency of the NITSC are analytically derived. The operating temperature of the TRC is determined through the thermal equilibrium equations, and the efficiency of the NITSC is calculated through the optimization of the output voltage of the TRC and the concentrating factor for a given value of the bandgap. Moreover, the maximum efficiencies of the NITSC at different conditions and the optimal values of the bandgap are determined, and consequently, the corresponding optimum operating conditions are obtained. The results obtained here will be helpful for the optimum design and operation of TRCs.

  13. Radiation exchange

    SciTech Connect

    Taylor, J.H. )

    1990-01-01

    This book deals with radiation laws, the phenomena of radiation exchange, the quantification of radiation, and the mechanisms whereby radiation is attenuated in passing through the earth's atmosphere. Applications of radiation exchange are discussed, such as the measurement of the effective radiating temperature of the ozonosphere. Also presented is the development of the concept of atmospheric windows and atmospheric transmittance. Radiation exchange experiments between Earth and space are presented and their interpretations given. The book fives detailed, step-by-step procedures for carrying out the radiometric calibration of an infrared prism spectrometer and a radiation thermopile.

  14. Atmospheric radiation

    SciTech Connect

    Harshvardhan, M.R. )

    1991-01-01

    Studies of atmospheric radiative processes are summarized for the period 1987-1990. Topics discussed include radiation modeling; clouds and radiation; radiative effects in dynamics and climate; radiation budget and aerosol effects; and gaseous absorption, particulate scattering and surface reflection. It is concluded that the key developments of the period are a defining of the radiative forcing to the climate system by trace gases and clouds, the recognition that cloud microphysics and morphology need to be incorporated not only into radiation models but also climate models, and the isolation of a few important unsolved theoretical problems in atmospheric radiation.

  15. Pelvic radiation - discharge

    MedlinePlus

    Radiation of the pelvis - discharge; Cancer treatment - pelvic radiation; Prostate cancer - pelvic radiation; Ovarian cancer - pelvic radiation; Cervical cancer - pelvic radiation; Uterine cancer - pelvic radiation; Rectal cancer - ...

  16. Radiation Basics

    EPA Pesticide Factsheets

    Radiation can come from unstable atoms or it can be produced by machines. There are two kinds of radiation; ionizing and non-ionizing radiation. Learn about alpha, beta, gamma and x-ray radiation, as well the different types of doses.

  17. Culture-negative endocarditis

    MedlinePlus

    ... inflammation of the lining of one or more heart valves, but no endocarditis-causing germs can be found ... the heart, where they can settle on damaged heart valves. Alternative Names Endocarditis (culture-negative) Images Culture-negative ...

  18. [Negative symptoms: which antipsychotics?].

    PubMed

    Maurel, M; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    Treating negative symptoms of schizophrenia is a major issue and a challenge for the functional and social prognosis of the disease, to which they are closely linked. First- and second-generation antipsychotics allow a reduction of all negative symptoms. The hope of acting directly on primary negative symptoms with any antipsychotic is not supported by the literature. However, the effectiveness of first- and second-generation antipsychotics is demonstrated on secondary negative symptoms. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  19. Negative ion generator

    DOEpatents

    Stinnett, Regan W.

    1984-01-01

    A negative ion generator is formed from a magnetically insulated transmission line having a coating of graphite on the cathode for producing negative ions and a plurality of apertures on the opposed anode for the release of negative ions. Magnetic insulation keeps electrons from flowing from the cathode to the anode. A transverse magnetic field removes electrons which do escape through the apertures from the trajectory of the negative ions.

  20. Negative ion generator

    DOEpatents

    Stinnett, R.W.

    1984-05-08

    A negative ion generator is formed from a magnetically insulated transmission line having a coating of graphite on the cathode for producing negative ions and a plurality of apertures on the opposed anode for the release of negative ions. Magnetic insulation keeps electrons from flowing from the cathode to the anode. A transverse magnetic field removes electrons which do escape through the apertures from the trajectory of the negative ions. 8 figs.

  1. Sentential Negation in English

    ERIC Educational Resources Information Center

    Mowarin, Macaulay

    2009-01-01

    This paper undertakes a detailed analysis of sentential negation in the English language with Chomsky's Government-Binding theory of Transformational Grammar as theoretical model. It distinguishes between constituent and sentential negation in English. The essay identifies the exact position of Negation phrase in an English clause structure. It…

  2. Sentential Negation in English

    ERIC Educational Resources Information Center

    Mowarin, Macaulay

    2009-01-01

    This paper undertakes a detailed analysis of sentential negation in the English language with Chomsky's Government-Binding theory of Transformational Grammar as theoretical model. It distinguishes between constituent and sentential negation in English. The essay identifies the exact position of Negation phrase in an English clause structure. It…

  3. Space Radiation

    NASA Technical Reports Server (NTRS)

    Wu, Honglu

    2006-01-01

    Astronauts receive the highest occupational radiation exposure. Effective protections are needed to ensure the safety of astronauts on long duration space missions. Increased cancer morbidity or mortality risk in astronauts may be caused by occupational radiation exposure. Acute and late radiation damage to the central nervous system (CNS) may lead to changes in motor function and behavior, or neurological disorders. Radiation exposure may result in degenerative tissue diseases (non-cancer or non-CNS) such as cardiac, circulatory, or digestive diseases, as well as cataracts. Acute radiation syndromes may occur due to occupational radiation exposure.

  4. Radiation Therapy: Professions in Radiation Therapy

    MedlinePlus

    ... Resources Professions Site Index A-Z Professions in Radiation Therapy Radiation Oncologist Therapeutic Medical Physicist Radiation Therapist Dosimetrist Radiation Oncology Nurse Social Worker Dietitian Radiation Oncologist Radiation oncologists are physicians who oversee the ...

  5. Negative symptoms: psychopathological models.

    PubMed Central

    Ananth, J; Djenderdjian, A; Shamasunder, P; Costa, J; Herrera, J; Sramek, J

    1991-01-01

    The psychopathological manifestations of schizophrenia have been broadly divided into positive and negative symptom groups. Even though there is no definitive consensus, psychomotor agitation, motor excitement, hallucinations, delusions and thought disorder constitute positive and psychomotor retardation, amotivation, apathy and decreased emotional expression are grouped into negative symptoms. The negative symptoms have been reported to appear late in the course of the illness and resistant to treatment with neuroleptics. While these claims have not been substantiated, the current interest on negative symptoms is related to the fact that many nonfunctioning institutionalized as well as ambulatory schizophrenics manifest negative symptoms. As chronic psychiatric beds have become scarce, many patients with negative symptoms who were harbored in the chronic mental hospitals have been released to the community care and some of these patients live on the streets. Thus their visibility has challenged psychiatry to focus its efforts on the etiology and treatment of negative symptoms. PMID:2049366

  6. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. SWITCHGEAR AND POWER GENERATOR MOTORS, MECHANICAL SECTION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  7. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. WALL AND WINDOW OVERLOOKING MAGNET ROOM, SECOND STORY OFFICE-AND-SHOPS SECTION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  8. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. ROOF BLOCKS, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  9. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. STAIRWAY FROM MAIN FLOOR TO SECOND FLOOR OF MECHANICAL WINE, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  10. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. SWITCHGEAR AND POWER GENERATOR MOTORS, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  11. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. END OF BEAMLINE LEAVING SHIELDING, MAGNET COILS IN EPOXY, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  12. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. REMNANTS OF HYDRAULIC FIXTURES, FAN ROOM, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  13. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. BEVATRON IN CENTER OF MAGNET ROOM - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  14. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. GENERATOR MOTORS OPPOSITE SWITCHGEAR RACKS, MECHANIC SECTION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  15. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. PUMP MOUNTS, FAN ROOM, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  16. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. ENTRANCE TO STAIRWAY TO TUNNEL UNDER MAIN FLOOR OF MAGNET ROOM, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  17. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. SIDE OF MAGNET OF BEAMLINE EXITING SHIELDING, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  18. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. FLOOR AND CEILING OF MAGNET ROOM, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  19. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. SWITCHGEAR, MECHANICAL SECTION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  20. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. MAGNET OF BEAMLINE, EXITING SHIELDING, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  1. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. STUB OF BEAMLINE EXITING SHIELDING, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  2. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. GENERATOR ROOM, MECHANICAL SECTION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  3. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. CENTRAL SUPPORT COLUMN EXTENDING THROUGH CRANES AND ROOF SUPPORT TRUSS, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  4. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. STAIRWAY FROM MAIN FLOOR OF 51A TO SECOND FLOOR EXTERIOR EXIT, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  5. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. CABLE RACEWAYS, CATWALK, AND WINDOWS OF OFFICE-AND-SHOPS SECTION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  6. Radiation safety.

    PubMed

    Skinner, Sarah

    2013-06-01

    Diagnostic radiology procedures, such as computed tomography (CT) and X-ray, are an increasing source of ionising radiation exposure to our community. Exposure to ionising radiation is associated with increased risk of malignancy, proportional to the level of exposure. Every diagnostic test using ionising radiation needs to be justified by clinical need. General practitioners need a working knowledge of radiation safety so they can adequately inform their patients of the risks and benefits of diagnostic imaging procedures.

  7. Radiation Exposure

    MedlinePlus

    Radiation is energy that travels in the form of waves or high-speed particles. It occurs naturally in sunlight. Man-made radiation is used in X-rays, nuclear weapons, nuclear power plants and cancer treatment. If you are exposed to small amounts of radiation over a ...

  8. Can radiative forcing be limited to 2.6 Wm-2 without negative emissions from bioenergy Aand CO2 capture and storage?

    SciTech Connect

    Edmonds, James; Luckow, Patrick; Calvin, Katherine; Wise, Marshall; Dooley, Jim; Kyle, Page; Kim, Son H.; Patel, Pralit; Clarke, Leon

    2013-01-18

    Combining bioenergy and carbon dioxide (CO2) capture and storage (CCS) technologies (BECCS) has the potential to remove CO2 from the atmosphere while producing useful energy. BECCS has played a central role in scenarios that reduce climate forcing to low levels such as 2.6Wm-2. In this paper we consider whether BECCS is essential to limiting radiative forcing (RF) to 2.6Wm-2 by 2100 using the Global Change Assessment Model, a closely coupled model of biogeophysical and human Earth systems. We show that BECCS can potentially reduce the cost of limiting RF to 2.6Wm-2 by 2100 but that a variety of technology combinations that do not include BECCS can also achieve this goal, under appropriate emissions mitigation policies. We note that with appropriate supporting land-use policies terrestrial sequestration could deliver carbon storage ranging from 200 to 700 PgCO2-equiavalent over the 21st century. We explore substantial delays in participation by some geopolitical regions. We find that the value of BECCS is substantially higher under delay and that delay results in higher transient RF and climate change. However, when major regions postponed mitigation indefinitely, it was impossible to return RF to 2.6Wm-2 by 2100. Neither finite land resources nor finite potential geologic storage capacity represented a meaningful technical limit on the ability of BECCS to contribute to emissions mitigation in the numerical experiments reported in this paper.

  9. A randomized, double-blind, negatively controlled pilot study to determine whether the use of emollients or calcipotriol alters the sensitivity of the skin to ultraviolet radiation during phototherapy with narrowband ultraviolet B.

    PubMed

    Skellett, A; Swift, L; Tan, E; Garioch, J

    2011-02-01

    There is contradictory evidence suggesting that emollients increase, decrease or have no effect on minimal erythema dose (MED) or minimal phototoxic dose values prior to phototherapy. Few studies have looked at the in vivo use of emollients or calcipotriol prior to narrowband ultraviolet (UV) B (NB-UVB) treatment. To investigate whether emollients or calcipotriol alter MED readings of skin on the back of healthy subjects prior to NB-UVB irradiation. Topical agents were applied to the backs of 20 healthy volunteers for 30 min prior to MED testing. These agents were aqueous cream, 50:50 white soft paraffin and liquid paraffin, Diprobase(®) (Schering-Plough, Welwyn Garden City, U.K.), Epaderm(®) (Medlock, Oldham, U.K.) and calcipotriol ointment and cream. A control MED strip was used with no topical agent applied prior to testing. MED readings were recoded as integer steps between 1 and 9 (one is lowest MED dose for skin type; eight is highest; nine is no response, i.e. a higher MED). The median MED was between step 5 and 6 for all treatments and control. There was no significant difference at the 5% level between control and each topical agent. The study was powered to detect a median difference of approximately 0·4-0·6 steps. This has important implications at a practical level when advising patients not to apply creams prior to treatment with NB-UVB. Studies where agents are applied immediately prior to phototherapy have been more likely to show that emollients block transmission of UV radiation. If they are applied at least 30 min prior to treatment, they have no effect. © 2011 The Authors. BJD © 2011 British Association of Dermatologists.

  10. Radiation Proctopathy

    PubMed Central

    Grodsky, Marc B.; Sidani, Shafik M.

    2015-01-01

    Radiation therapy is a widely utilized treatment modality for pelvic malignancies, including prostate cancer, rectal cancer, and cervical cancer. Given its fixed position in the pelvis, the rectum is at a high risk for injury secondary to ionizing radiation. Despite advances made in radiation science, up to 75% of the patients will suffer from acute radiation proctitis and up to 20% may experience chronic symptoms. Symptoms can be variable and include diarrhea, bleeding, incontinence, and fistulization. A multitude of treatment options exist. This article summarizes the latest knowledge relating to radiation proctopathy focusing on the vast array of treatment options. PMID:26034407

  11. Negative Ion Density Fronts

    SciTech Connect

    Igor Kaganovich

    2000-12-18

    Negative ions tend to stratify in electronegative plasmas with hot electrons (electron temperature Te much larger than ion temperature Ti, Te > Ti ). The boundary separating a plasma containing negative ions, and a plasma, without negative ions, is usually thin, so that the negative ion density falls rapidly to zero-forming a negative ion density front. We review theoretical, experimental and numerical results giving the spatio-temporal evolution of negative ion density fronts during plasma ignition, the steady state, and extinction (afterglow). During plasma ignition, negative ion fronts are the result of the break of smooth plasma density profiles during nonlinear convection. In a steady-state plasma, the fronts are boundary layers with steepening of ion density profiles due to nonlinear convection also. But during plasma extinction, the ion fronts are of a completely different nature. Negative ions diffuse freely in the plasma core (no convection), whereas the negative ion front propagates towards the chamber walls with a nearly constant velocity. The concept of fronts turns out to be very effective in analysis of plasma density profile evolution in strongly non-isothermal plasmas.

  12. Radiation Protection

    NASA Astrophysics Data System (ADS)

    Grupen, Claus

    Radiation protection is a very important aspect for the application of particle detectors in many different fields, like high energy physics, medicine, materials science, oil and mineral exploration, and arts, to name a few. The knowledge of radiation units, the experience with shielding, and information on biological effects of radiation are vital for scientists handling radioactive sources or operating accelerators or X-ray equipment. This article describes the modern radiation units and their conversions to older units which are still in use in many countries. Typical radiation sources and detectors used in the field of radiation protection are presented. The legal regulations in nearly all countries follow closely the recommendations of the International Commission on Radiological Protection (ICRP). Tables and diagrams with relevant information on the handling of radiation sources provide useful data for the researcher working in this field.

  13. Malignant mesothelioma following radiation exposure

    SciTech Connect

    Antman, K.H.; Corson, J.M.; Li, F.P.; Greenberger, J.; Sytkowski, A.; Henson, D.E.; Weinstein, L.

    1983-11-01

    Mesothelioma developed in proximity to the field of therapeutic radiation administered 10-31 years previously in four patients. In three, mesothelioma arose within the site of prior therapeutic radiation for another cancer. Mesothelioma in the fourth patient developed adjacent to the site of cosmetic radiation to a thyroidectomy scar. None of these four patients recalled an asbestos exposure or had evidence of asbestosis on chest roentgenogram. Lung tissue in one patient was negative for ferruginous bodies, a finding considered to indicate no significant asbestos exposure. Five other patients with radiation-associated mesothelioma have been reported previously, suggesting that radiation is an uncommon cause of human mesothelioma. Problems in the diagnosis of radiation-associated mesotheliomas are considered.

  14. Negative Human Interaction

    ERIC Educational Resources Information Center

    Brannan, John M.

    1972-01-01

    This study is an effort to examine man's most negative experiences as he perceives them. The results indicated that teachers were involved more often than any other person in the most negative experience reported. Improved human relations skills are clearly indicated for those in higher education as well as in public schools. (Author)

  15. Radiation safety

    SciTech Connect

    Benson, J.M.

    1982-09-01

    Radiation safety is rapidly becoming a major concern of every patient. Poor understanding of ionizing radiation and its effects frequently heightens anxiety. The average United States resident receives about 125 mrem of radiation per year from natural background radiation and another 120 mrem from man-made sources. The 240 million x-ray procedures performed annually contribute 90 percent of the man-made portion. It is assumed that the risks of medical radiation are outweighed by the benefits gained from the information obtained. If present in sufficiently high dosage, radiation can have harmful effects, such as induction of leukemia and thyroid malignancy. No deleterious effects have been shown to have been caused by diagnostic radiation. It is reassuring that the risks of medical radiation appear to be quite small compared with other common hazards most people face daily. Careful attention to the use of radiographic safety and protective technique will ensure the lowest possible radiation dose. The physician's discretion in ordering only appropriate and indicated x-ray films will ensure the patients are exposed to the lowest possible amount of radiation.

  16. Radiator technology

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.

    1993-01-01

    Radiator technology is discussed in the context of the Civilian Space Technology Initiative's (CSTI's) high capacity power-thermal management project. The CSTI project is a subset of a project to develop a piloted Mars nuclear electric propulsion (NEP) vehicle. The following topics are presented in vugraph form: advanced radiator concepts; heat pipe codes and testing; composite materials; radiator design and integration; and surface morphology.

  17. Hawking radiation

    NASA Astrophysics Data System (ADS)

    Parentani, Renaud; Spindel, Philippe

    2011-12-01

    Hawking radiation is the thermal radiation predicted to be spontaneously emitted by black holes. It arises from the steady conversion of quantum vacuum fluctuations into pairs of particles, one of which escaping at infinity while the other is trapped inside the black hole horizon. It is named after the physicist Stephen Hawking who derived its existence in 1974. This radiation reduces the mass of black holes and is therefore also known as black hole evaporation.

  18. Photosynthesis and negative entropy production.

    PubMed

    Jennings, Robert C; Engelmann, Enrico; Garlaschi, Flavio; Casazza, Anna Paola; Zucchelli, Giuseppe

    2005-09-30

    The widely held view that the maximum efficiency of a photosynthetic pigment system is given by the Carnot cycle expression (1-T/Tr) for energy transfer from a hot bath (radiation at temperature Tr) to a cold bath (pigment system at temperature T) is critically examined and demonstrated to be inaccurate when the entropy changes associated with the microscopic process of photon absorption and photochemistry at the level of single photosystems are considered. This is because entropy losses due to excited state generation and relaxation are extremely small (DeltaS < T/Tr) and are essentially associated with the absorption-fluorescence Stokes shift. Total entropy changes associated with primary photochemistry for single photosystems are shown to depend critically on the thermodynamic efficiency of the process. This principle is applied to the case of primary photochemistry of the isolated core of higher plant photosystem I and photosystem II, which are demonstrated to have maximal thermodynamic efficiencies of xi > 0.98 and xi > 0.92 respectively, and which, in principle, function with negative entropy production. It is demonstrated that for the case of xi > (1-T/Tr) entropy production is always negative and only becomes positive when xi < (1-T/Tr).

  19. Materials with negative stiffness

    NASA Astrophysics Data System (ADS)

    Jaglinski, Tim

    Negative stiffness, or a reversal in the usual assumed direction between causal forces and ensuing deformations, has been proposed as a pathway to materials which exceed theoretical performance bounds. Negative stiffness, as a concept, represents a relaxation of tacitly assumed material behavior, but it violates no natural laws. Negative stiffness, normally unstable without constraint, is permissible for stability under special conditions, for example a rigid boundary constraint so long as the material satisfies strong ellipticity in the parlance of elasticity. Hence, negative stiffness is not observed in materials or structures which are not constrained. If negative stiffness is allowed for inclusions of material, which are surrounded by a stabilizing positive stiffness matrix, composite theory predicts large increases in the mechanical damping and composite stiffness. The work herein explores several material systems which possess negative stiffness, and seeks to characterize the composite mechanical properties of these systems. Two metal matrix composite systems, namely Sn-VO2 and Sn-BaTIO3, were investigated. Here, negative stiffness arises from the ferroelastic phase transformations in the ceramic inclusions; stability is imparted by the tin matrix. Polycrystalline In-Tl and BaTIO 3 were also studied. Here, the entire material volume is phase transforming. Constraint is imparted on a small volume fraction of crystallites by the surrounding material. Various manifestations of negative stiffness were observed. Thermally broad damping peaks which depended upon thermal cycling were observed in the Sn-VO2 composites. Furthermore, mechanical instabilities were seen in composites intentionally designed to be unstable. Negative stiffness was indicated in the In-Tl alloy by magnification of damping peaks over those observed in single crystals, increases in damping peaks with increased cooling rates, occurrence of damping peaks before the appearance of martensite and

  20. Negative birefringent polyimide films

    NASA Technical Reports Server (NTRS)

    Harris, Frank W. (Inventor); Cheng, Stephen Z. D. (Inventor)

    1994-01-01

    A negative birefringent film, useful in liquid crystal displays, and a method for controlling the negative birefringence of a polyimide film is disclosed which allows the matching of an application to a targeted amount of birefringence by controlling the degree of in-plane orientation of the polyimide by the selection of functional groups within both the diamine and dianhydride segments of the polyimide which affect the polyimide backbone chain rigidity, linearity, and symmetry. The higher the rigidity, linearity and symmetry of the polyimide backbone, the larger the value of the negative birefringence of the polyimide film.

  1. Negative tandem mirror

    SciTech Connect

    Poulsen, P.; Allen, S.L.; Casper, T.A.; Grubb, D.P.; Jong, R.A.; Nexsen, W.E.; Porter, G.D.; Simonen, T.C.

    1981-11-30

    A tandem mirror configuration can be created by combining hot electron end cell plasmas with neutral beam pumping. A region of large negative potential formed in each end cell confines electrons in the central cell. The requirement of charge neutrality causes the central cell potential to become negative with respect to ground in order to confine ions as well as electrons. We discuss the method of producing and calculating the desired axial potential profile, and show the calculated axial potential profile and plasma parameters for a negative configuration of TMX-Upgrade.

  2. Atomic negative ions

    SciTech Connect

    Brage, T.

    1991-01-01

    We review some of the recent progress in the studies of alkaline-earth, negative ions. Computations of autodetachment rates, electron affinities and transition wavelengths are discussed and some new and improved results are given.

  3. Atomic negative ions

    SciTech Connect

    Brage, T.

    1991-12-31

    We review some of the recent progress in the studies of alkaline-earth, negative ions. Computations of autodetachment rates, electron affinities and transition wavelengths are discussed and some new and improved results are given.

  4. Negative electrode composition

    DOEpatents

    Kaun, Thomas D.; Chilenskas, Albert A.

    1982-01-01

    A secondary electrochemical cell and a negative electrode composition for use therewith comprising a positive electrode containing an active material of a chalcogen or a transiton metal chalcogenide, a negative electrode containing a lithium-aluminum alloy and an amount of a ternary alloy sufficient to provide at least about 5 percent overcharge capacity relative to a negative electrode solely of the lithium-aluminum alloy, the ternary alloy comprising lithium, aluminum, and iron or cobalt, and an electrolyte containing lithium ions in contact with both of the positive and the negative electrodes. The ternary alloy is present in the electrode in the range of from about 5 percent to about 50 percent by weight of the electrode composition and may include lithium-aluminum-nickel alloy in combination with either the ternary iron or cobalt alloys. A plurality of series connected cells having overcharge capacity can be equalized on the discharge side without expensive electrical equipment.

  5. Negative linear compressibility.

    PubMed

    Cairns, Andrew B; Goodwin, Andrew L

    2015-08-28

    While all materials reduce their intrinsic volume under hydrostatic (uniform) compression, a select few actually expand along one or more directions during this process of densification. As rare as it is counterintuitive, such "negative compressibility" behaviour has application in the design of pressure sensors, artificial muscles and actuators. The recent discovery of surprisingly strong and persistent negative compressibility effects in a variety of new families of materials has ignited the field. Here we review the phenomenology of negative compressibility in this context of materials diversity, placing particular emphasis on the common structural motifs that recur amongst known examples. Our goal is to present a mechanistic understanding of negative compressibility that will help inform a clear strategy for future materials design.

  6. Logo and Negative Numbers.

    ERIC Educational Resources Information Center

    Strawn, Candace A.

    1998-01-01

    Describes LOGO's turtle graphics capabilities based on a sixth-grade classroom's activities with negative numbers and Logo programming. A sidebar explains LOGO and offers suggestions to teachers for using LOGO effectively. (LRW)

  7. Radiation of partially ionized atomic hydrogen

    NASA Technical Reports Server (NTRS)

    Soon, W. H.; Kunc, J. A.

    1990-01-01

    A nonlinear collisional-radiative model for determination of production of electrons, positive and negative ions, excited atoms, and spectral and continuum line intensities in stationary partially ionized atomic hydrogen is presented. Transport of radiation is included by coupling the rate equations for production of the electrons, ions, and excited atoms with the radiation escape factors, which are not constant but depend on plasma conditions. It is found that the contribution of the negative ion emission to the total continuum emission can be important. Comparison of the calculated total continuum emission coefficient, including the negative ion emission, is in good agreement with experimental results.

  8. No to negative data

    SciTech Connect

    Wiley, H. S.

    2008-04-01

    A frequent criticism in biology is that we don’t publish our negative data. As a result, the literature has become biased towards papers that favor specific hypotheses1. Some scientists have become so concerned about this trend that they have created journals dedicated to publishing negative results (e.g. the Journal of Negative Results in Biomedicine). Personally, I don’t think they should bother. I say this because I believe negative results are not worth publishing. Rest assured that I do not include drug studies that show a lack of effectiveness towards a specific disease or condition. This type of finding is significant in a societal context, not a scientific one, and thus we all have a vested interest in seeing this type of result published. I am talking about a set of experimental results that fail to support a particular hypothesis. The problem with these types of negative results is that they don’t actually advance science. Science is a set of ideas that can be supported by observations. A negative result does not support any specific idea, but only tells you what isn’t right. Well, there are only a small number of potential hypotheses that are correct, but essentially an infinite number of ideas are not correct. I don’t want to waste my time reading a paper about what doesn’t happen, just about those things that do. I can remember a positive result because I can associate it with a specific concept. What do I do with a negative one? It is hard enough to following the current literature. A flood of negative results would make that task all but impossible

  9. Negative symptoms in schizophrenia.

    PubMed

    Boutros, Nash N; Mucci, Armida; Diwadkar, Vaibhav; Tandon, Rajiv

    2014-04-01

    Clinical heterogeneity is a confound common to all of schizophrenia research. Deficit schizophrenia has been proposed as a homogeneous disease entity within the schizophrenia syndrome. Utilizing the Schedule for the Deficit Syndrome (SDS) has allowed the definition of a subgroup dominated by persistent clusters of negative symptoms. While a number of studies have appeared over the years examining the electrophysiological correlates of the cluster of negative symptoms in schizophrenia, only a few studies have actually focused on the deficit syndrome (DS). PubMed as well as MEDLINE were searched for all reports indexed for "negative symptoms" or "deficit syndrome" and one of the following electrophysiology assessment tools: electroencephalography (EEG), evoked potentials (EPs), or polysomnography (PSG). While this line of research is evidently in its infancy, two significant trends emerge. First, spectral EEG studies link increased slow wave activity during wakefulness to the prevalence of negative symptoms. Secondly, sleep studies point to an association between decrease in slow wave sleep and prevalence of negative symptoms. Several studies also indicate a relationship of negative symptoms with reduced alpha activity. A host of other abnormalities--including sensory gating and P300 attenuation--are less consistently reported. Two studies specifically addressed electrophysiology of the DS. Both studies provided evidence suggesting that the DS may be a separate disease entity and not simply a severe form of schizophrenia.

  10. Radiative Forcing by Contrails

    NASA Technical Reports Server (NTRS)

    Meerkoetter, R.; Schumann, U.; Doelling, D. R.; Nakajima, T.; Tsushima, Y.

    1999-01-01

    A parametric study of the instantaneous radiative impact of contrails is presented using three different radiative transfer models for a series of model atmospheres and cloud parameters. Contrails are treated as geometrically and optically thin plane parallel homogeneous cirrus layers in a static atmospheres The ice water content is varied as a function of ambient temperature. The model atmospheres include tropical, mid-latitude, and subarctic summer and winter atmospheres Optically thin contrails cause a positive net forcing at top of the atmosphere. At the surface the radiative forcing is negative during daytime. The forcing increases with the optical depth and the amount of contrail cover. At the top of the atmosphere a mean contrail cover of 0.1% with average optical depth of 0.2 to 0.5 causes about 0.01 to 0.03 W/m(exp 2)a daily mean instantaneous radiative forcing. Contrails cool the surface during the day and heat the surface during the night, and hence reduce the daily temperature amplitude The net effect depends strongly on the daily variation of contrail cloud cover. The indirect radiative forcing due to particle changes in natural cirrus clouds may be of the same magnitude as the direct one due to additional cover.

  11. Radiative Forcing by Contrails

    NASA Technical Reports Server (NTRS)

    Meerkoetter, R.; Schumann, U.; Doelling, D. R.; Nakajima, T.; Tsushima, Y.

    1999-01-01

    A parametric study of the instantaneous radiative impact of contrails is presented using three different radiative transfer models for a series of model atmospheres and cloud parameters. Contrails are treated as geometrically and optically thin plane parallel homogeneous cirrus layers in a static atmospheres The ice water content is varied as a function of ambient temperature. The model atmospheres include tropical, mid-latitude, and subarctic summer and winter atmospheres Optically thin contrails cause a positive net forcing at top of the atmosphere. At the surface the radiative forcing is negative during daytime. The forcing increases with the optical depth and the amount of contrail cover. At the top of the atmosphere a mean contrail cover of 0.1% with average optical depth of 0.2 to 0.5 causes about 0.01 to 0.03 W/m(exp 2)a daily mean instantaneous radiative forcing. Contrails cool the surface during the day and heat the surface during the night, and hence reduce the daily temperature amplitude The net effect depends strongly on the daily variation of contrail cloud cover. The indirect radiative forcing due to particle changes in natural cirrus clouds may be of the same magnitude as the direct one due to additional cover.

  12. Understanding Radiation.

    ERIC Educational Resources Information Center

    Department of Energy, Washington, DC. Nuclear Energy Office.

    Radiation is a natural energy force that has been a part of the environment since the Earth was formed. It takes various forms, none of which can be smelled, tasted, seen, heard, or felt. Nevertheless, scientists know what it is, where it comes from, how to measure and detect it, and how it affects people. Cosmic radiation from outer space and…

  13. Diffuse radiation

    NASA Technical Reports Server (NTRS)

    1981-01-01

    A diffuse celestial radiation which is isotropic at least on a course scale were measured from the soft X-ray region to about 150 MeV, at which energy the intensity falls below that of the galactic emission for most galactic latitudes. The spectral shape, the intensity, and the established degree of isotropy of this diffuse radiation already place severe constraints on the possible explanations for this radiation. Among the extragalactic theories, the more promising explanations of the isotropic diffuse emission appear to be radiation from exceptional galaxies from matter antimatter annihilation at the boundaries of superclusters of galaxies of matter and antimatter in baryon symmetric big bang models. Other possible sources for extragalactic diffuse gamma radiation are discussed and include normal galaxies, clusters of galaxies, primordial cosmic rays interacting with intergalactic matter, primordial black holes, and cosmic ray leakage from galaxies.

  14. Radiation detector

    DOEpatents

    Fultz, Brent T.

    1983-01-01

    Apparatus is provided for detecting radiation such as gamma rays and X-rays generated in backscatter Mossbauer effect spectroscopy and X-ray spectrometry, which has a large "window" for detecting radiation emanating over a wide solid angle from a specimen and which generates substantially the same output pulse height for monoenergetic radiation that passes through any portion of the detection chamber. The apparatus includes a substantially toroidal chamber with conductive walls forming a cathode, and a wire anode extending in a circle within the chamber with the anode lying closer to the inner side of the toroid which has the least diameter than to the outer side. The placement of the anode produces an electric field, in a region close to the anode, which has substantially the same gradient in all directions extending radially from the anode, so that the number of avalanche electrons generated by ionizing radiation is independent of the path of the radiation through the chamber.

  15. Radiation detector

    DOEpatents

    Fultz, B.T.

    1980-12-05

    Apparatus is provided for detecting radiation such as gamma rays and x-rays generated in backscatter Moessbauer effect spectroscopy and x-ray spectrometry, which has a large window for detecting radiation emanating over a wide solid angle from a specimen and which generates substantially the same output pulse height for monoenergetic radiation that passes through any portion of the detection chamber. The apparatus includes a substantially toroidal chamber with conductive walls forming a cathode, and a wire anode extending in a circle within the chamber with the anode lying closer to the inner side of the toroid which has the least diameter than to the outer side. The placement of the anode produces an electric field, in a region close to the anode, which has substantially the same gradient in all directions extending radially from the anode, so that the number of avalanche electrons generated by ionizing radiation is independent of the path of the radiation through the chamber.

  16. Radiation retinopathy.

    PubMed Central

    Zamber, R W; Kinyoun, J L

    1992-01-01

    Radiation therapy is effective against many cancerous and noncancerous disease processes. As with other therapeutics, side effects must be anticipated, recognized, and managed appropriately. Radiation retinopathy is a vision-threatening complication of ocular, orbital, periorbital, facial, nasopharyngeal, and cranial irradiation. Factors that appear important in the pathogenesis of radiation retinopathy include total radiation dosage, fraction size, concomitant chemotherapy, and preexisting vascular disorders. Clinical manifestations of the disorder include macular edema and nonproliferative and proliferative retinopathy, similar to changes seen in diabetic retinopathy. Argon laser photocoagulation has proved efficacious for managing macular edema and fibrovascular proliferation in some of these patients. Ongoing basic laboratory and clinical research efforts have led to a better understanding of the pathogenesis, natural history, and treatment response of radiation retinopathy. The ultimate goal of this knowledge is to improve the prevention, recognition, and management of this vision-threatening complication. Images PMID:1441494

  17. Space Radiation and Bone Loss

    PubMed Central

    Willey, Jeffrey S.; Lloyd, Shane A.J.; Nelson, Gregory A.; Bateman, Ted A.

    2011-01-01

    Exposure to ionizing radiation may negatively impact skeletal integrity during extended spaceflight missions to the moon, Mars, or near-Earth asteroids. However, our understanding of the effects of radiation on bone is limited when compared to the effects of weightlessness. In addition to microgravity, astronauts will be exposed to space radiation from solar and cosmic sources. Historically, radiation exposure has been shown to damage both osteoblast precursors and local vasculature within the irradiated volume. The resulting suppression of bone formation and a general state of low bone-turnover is thought to be the primary contributor to bone loss and eventual fracture. Recent investigations using mouse models have identified a rapid, but transient, increase in osteoclast activity immediately after irradiation with both spaceflight and clinically-relevant radiation qualities and doses. Together with a chronic suppression of bone formation after radiation exposure, this acute skeletal damage may contribute to long-term deterioration of bone quality, potentially increasing fracture risk. Direct evidence for the damaging effects of radiation on human bone are primarily demonstrated by the increased incidence of fractures at sites that absorb high doses of radiation during cancer therapy: exposures are considerably higher than what could be expected during spaceflight. However, both the rapidity of bone damage and the chronic nature of the changes appear similar between exposure scenarios. This review will outline our current knowledge of space and clinical exploration exposure to ionizing radiation on skeletal health. PMID:22826632

  18. Space Radiation and Bone Loss.

    PubMed

    Willey, Jeffrey S; Lloyd, Shane A J; Nelson, Gregory A; Bateman, Ted A

    2011-01-01

    Exposure to ionizing radiation may negatively impact skeletal integrity during extended spaceflight missions to the moon, Mars, or near-Earth asteroids. However, our understanding of the effects of radiation on bone is limited when compared to the effects of weightlessness. In addition to microgravity, astronauts will be exposed to space radiation from solar and cosmic sources. Historically, radiation exposure has been shown to damage both osteoblast precursors and local vasculature within the irradiated volume. The resulting suppression of bone formation and a general state of low bone-turnover is thought to be the primary contributor to bone loss and eventual fracture. Recent investigations using mouse models have identified a rapid, but transient, increase in osteoclast activity immediately after irradiation with both spaceflight and clinically-relevant radiation qualities and doses. Together with a chronic suppression of bone formation after radiation exposure, this acute skeletal damage may contribute to long-term deterioration of bone quality, potentially increasing fracture risk. Direct evidence for the damaging effects of radiation on human bone are primarily demonstrated by the increased incidence of fractures at sites that absorb high doses of radiation during cancer therapy: exposures are considerably higher than what could be expected during spaceflight. However, both the rapidity of bone damage and the chronic nature of the changes appear similar between exposure scenarios. This review will outline our current knowledge of space and clinical exploration exposure to ionizing radiation on skeletal health.

  19. [Radiation carcinogenesis].

    PubMed

    Hosoi, Yoshio

    2013-11-01

    Misrepair of DNA damage induced by ionizing radiation is a potential cause of carcinogenesis following exposure to radiation. Radiation exposure increases the incidence of the same types of mutations that occur spontaneously in a given population. A high incidence of DNA double-strand breaks is characteristic of damage by ionizing radiation compared with those induced by other environmental mutagens. In China, residents living in areas with high level background radiation(6mSv/y) had a significantly higher frequency of dicentric and ring chromosomes compared to that for the residents living in the control areas(2mSv/y). Radiation-associated increases in risk were seen for most sites. Gender-averaged excess absolute risk rates estimated at age 70, after exposure at age 30, differ in the sites, and the risks of gastric cancer, breast cancer, colon cancer, and lung cancer were highly increased, in that order. Latent periods for the development of leukemia and thyroid cancer after radiation exposure at ages younger than 18 were shorter compared to those for other solid cancers.

  20. Negative pressure wound therapy.

    PubMed

    Thompson, James T; Marks, Malcolm W

    2007-10-01

    Negative pressure wound therapy has become an increasingly important part of wound management. Over the last decade, numerous uses for this method of wound management have been reported, ranging from acute and chronic wounds, to closure of open sternal and abdominal wounds, to assistance with skin grafts. The biophysics behind the success of this treatment largely have focused on increased wound blood flow, increased granulation tissue formation, decreased bacterial counts, and stimulation of wound healing pathways through shear stress mechanisms. The overall success of negative pressure wound therapy has led to a multitude of clinical applications, which are discussed in this article.

  1. Radiation dosimeter

    DOEpatents

    Fox, Richard J.

    1983-01-01

    A radiation detector readout circuit is provided which produces a radiation dose-rate readout from a detector even though the detector output may be highly energy dependent. A linear charge amplifier including an output charge pump circuit amplifies the charge signal pulses from the detector and pumps the charge into a charge storage capacitor. The discharge rate of the capacitor through a resistor is controlled to provide a time-dependent voltage which when integrated provides an output proportional to the dose-rate of radiation detected by the detector. This output may be converted to digital form for readout on a digital display.

  2. Radiation dosimeter

    DOEpatents

    Fox, R.J.

    1981-09-01

    A radiation detector readout circuit is provided which produces a radiation dose-rate readout from a detector even through the detector output may be highly energy dependent. A linear charge amplifier including an output charge pump circuit amplifies the charge signal pulses from the detector and pumps the charge into a charge storage capacitor. The discharge rate of the capacitor through a resistor is controlled to provide a time-dependent voltage which when integrated provides an output proportional to the dose-rate of radiation detected by the detector. This output may be converted to digital form for readout on a digital display.

  3. Radiation Hydrodynamics

    SciTech Connect

    Castor, J I

    2003-10-16

    The discipline of radiation hydrodynamics is the branch of hydrodynamics in which the moving fluid absorbs and emits electromagnetic radiation, and in so doing modifies its dynamical behavior. That is, the net gain or loss of energy by parcels of the fluid material through absorption or emission of radiation are sufficient to change the pressure of the material, and therefore change its motion; alternatively, the net momentum exchange between radiation and matter may alter the motion of the matter directly. Ignoring the radiation contributions to energy and momentum will give a wrong prediction of the hydrodynamic motion when the correct description is radiation hydrodynamics. Of course, there are circumstances when a large quantity of radiation is present, yet can be ignored without causing the model to be in error. This happens when radiation from an exterior source streams through the problem, but the latter is so transparent that the energy and momentum coupling is negligible. Everything we say about radiation hydrodynamics applies equally well to neutrinos and photons (apart from the Einstein relations, specific to bosons), but in almost every area of astrophysics neutrino hydrodynamics is ignored, simply because the systems are exceedingly transparent to neutrinos, even though the energy flux in neutrinos may be substantial. Another place where we can do ''radiation hydrodynamics'' without using any sophisticated theory is deep within stars or other bodies, where the material is so opaque to the radiation that the mean free path of photons is entirely negligible compared with the size of the system, the distance over which any fluid quantity varies, and so on. In this case we can suppose that the radiation is in equilibrium with the matter locally, and its energy, pressure and momentum can be lumped in with those of the rest of the fluid. That is, it is no more necessary to distinguish photons from atoms, nuclei and electrons, than it is to distinguish

  4. PT -symmetric spectral singularity and negative-frequency resonance

    NASA Astrophysics Data System (ADS)

    Pendharker, Sarang; Guo, Yu; Khosravi, Farhad; Jacob, Zubin

    2017-03-01

    Vacuum consists of a bath of balanced and symmetric positive- and negative-frequency fluctuations. Media in relative motion or accelerated observers can break this symmetry and preferentially amplify negative-frequency modes as in quantum Cherenkov radiation and Unruh radiation. Here, we show the existence of a universal negative-frequency-momentum mirror symmetry in the relativistic Lorentzian transformation for electromagnetic waves. We show the connection of our discovered symmetry to parity-time (PT ) symmetry in moving media and the resulting spectral singularity in vacuum fluctuation-related effects. We prove that this spectral singularity can occur in the case of two metallic plates in relative motion interacting through positive- and negative-frequency plasmonic fluctuations (negative-frequency resonance). Our work paves the way for understanding the role of PT -symmetric spectral singularities in amplifying fluctuations and motivates the search for PT symmetry in novel photonic systems.

  5. The Negative Repetition Effect

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  6. The Negative Repetition Effect

    ERIC Educational Resources Information Center

    Mulligan, Neil W.; Peterson, Daniel J.

    2013-01-01

    A fundamental property of human memory is that repetition enhances memory. Peterson and Mulligan (2012) recently documented a surprising "negative repetition effect," in which participants who studied a list of cue-target pairs twice recalled fewer targets than a group who studied the pairs only once. Words within a pair rhymed, and…

  7. Radiation therapy

    MedlinePlus

    ... Intensity-modulated radiotherapy (IMRT) Image-guided radiotherapy (IGRT) Proton therapy is another kind of radiation used to ... than using x-rays to destroy cancer cells, proton therapy uses a beam of special particles called ...

  8. RADIATION DETECTOR

    DOEpatents

    Wilson, H.N.; Glass, F.M.

    1960-05-10

    A radiation detector of the type is described wherein a condenser is directly connected to the electrodes for the purpose of performing the dual function of a guard ring and to provide capacitance coupling for resetting the detector system.

  9. New radiobiological, radiation risk and radiation protection paradigms.

    PubMed

    Goodhead, Dudley T

    2010-05-01

    The long-standing conventional paradigm for radiobiology has formed a logical basis for the standard paradigm for radiation risk of cancer and heritable effects and, from these paradigms, has developed the internationally applied system for radiation protection, but with many simplifications, assumptions and generalizations. A variety of additional radiobiological phenomena that do not conform to the standard paradigm for radiobiology may have potential implications for radiation risk and radiation protection. It is suggested, however, that the current state of knowledge is still insufficient for these phenomena, individually or collectively, to be formulated systematically into a new paradigm for radiobiology. Additionally, there is at present lack of direct evidence of their relevance to risk for human health, despite attractive hypotheses as to how they might be involved. Finally, it remains to be shown how incorporation of such phenomena into the paradigm for radiation protection would provide sufficient added value to offset disruption to the present widely applied system. Further research should aim for better mechanistic understanding of processes such as radiation-induced genomic instability (for all radiation types) and bystander effects (particularly for low-fluence high-LET particles) and also priority should be given to confirmation, or negation, of the relevance of the processes to human health risks from radiation. Copyright 2010 Elsevier B.V. All rights reserved.

  10. Electromagnetic waves: Negative refraction by photonic crystals

    NASA Astrophysics Data System (ADS)

    Ozbay, Ekmel

    2004-03-01

    Recently left-handed materials (LHM) attracted great attention since these materials exhibit negative effective index, which is due to simultaneously negative permeability and permittivity. Pendry proposed that negative effective index in left-handed materials can be used for constructing a perfect lens, which is not limited by diffraction(J. B. Pendry, Negative refraction makes a perfect lens, Phys. Rev. Lett. vol. 85, 3966 (2000)). Negative refraction is also achievable in a dielectric photonic crystal (PC) that has a periodically modulated positive permittivity and a permeability of unity. Luo et al. has studied negative refraction and subwavelength imaging in photonic crystals(C. Luo, S. G. Johnson, J. D. Joannopoulos, J. B. Pendry, Subwavelength Imaging in Photonic Crystals Phys. Rev. B 68, 045115 (2003)). In this presentation, we report our experimental and theoretical investigation of negative refraction and subwavelength focusing of electromagnetic waves in a 2D PC. Our structure consists of a square array of dielectric rods in air. Transmission measurements are performed for experimentally verifying the predicted negative refraction behavior in our structure. Negative index of refraction determined from the experiment is -1.94 which is very close to the theoretical value of -2.06. Negative refraction is observed for the incidence angles of > 20°(Ertugrul Cubukcu, Koray Aydin, Ekmel Ozbay, S. Foteinopolou, and Costas Soukoulis, Negative Refraction by Photonic Crystals, Nature, vol. 423, 604 (2003)). Since we know the optimum frequency for a broad angle negative refraction, we can use our crystal to test the superlensing effect that was predicted for negative refractive materials. Scanning transmission measurement technique is used to measure the spatial power distribution of the focused electromagnetic waves that radiate from a point source. Full width at half maximum of the focused beam is measured to be 0.21λ, which is in good agreement with the finite

  11. Radiation Transport

    SciTech Connect

    Urbatsch, Todd James

    2015-06-15

    We present an overview of radiation transport, covering terminology, blackbody raditation, opacities, Boltzmann transport theory, approximations to the transport equation. Next we introduce several transport methods. We present a section on Caseology, observing transport boundary layers. We briefly broach topics of software development, including verification and validation, and we close with a section on high energy-density experiments that highlight and support radiation transport.

  12. Radiation enteritis.

    PubMed

    Harb, Ali H; Abou Fadel, Carla; Sharara, Ala I

    2014-01-01

    Radiation enteritis continues to be a major health concern in recipients of radiation therapy. The incidence of radiation enteritis is expected to continue to rise during the coming years paralleling the unprecedented use of radiotherapy in pelvic cancers. Radiation enteritis can present as either an acute or chronic syndrome. The acute form presents within hours to days of radiation exposure and typically resolves within few weeks. The chronic form may present as early as 2 months or as long as 30 years after exposure. Risk factors can be divided into patient and treatment-related factors. Chronic radiation enteritis is characterized by progressive obliterative endarteritis with exaggerated submucosal fibrosis and can manifest by stricturing, formation of fistulae, local abscesses, perforation, and bleeding. In the right clinical context, diagnosis can be confirmed by cross-sectional imaging, flexible or video capsule endoscopy. Present treatment strategies are directed primarily towards symptom relief and management of emerging complications. Recently, however, there has been a shift towards rational drug design based on improved understanding of the molecular basis of disease in an effort to limit the fibrotic process and prevent organ damage.

  13. Interaction Between Topological Defects and Radiation

    NASA Astrophysics Data System (ADS)

    Romanczukiewicz, T.

    2005-12-01

    The spectral structure of linearization around soliton in the phi 4 and s-G models is presented. Negative radiation pressure in phi 4 model is discussed and analytical calculation presented in the second order. The production of topological defects forced by radiation coupled to the internal degree of freedom of soliton is studied. The fractal boundary for this creation is also described.

  14. Quantum radiation of general nonstationary black holes

    NASA Astrophysics Data System (ADS)

    Hua, Jia-Chen; Huang, Yong-Chang

    2009-02-01

    Quantum radiation of general nonstationary black holes is investigated by using the method of generalized tortoise-coordinate transformation (GTT). It is shown in general that the temperature and the shape of the event horizon of this kind of black holes depend on time and angle. Further, we find that the chemical potential in the thermal-radiation spectrum is equal to the highest energy of the negative-energy state of particles in nonthermal radiation for general nonstationary black holes.

  15. Negative refraction and superconductivity

    NASA Astrophysics Data System (ADS)

    Amariti, Antonio; Forcella, Davide; Mariotti, Alberto; Siani, Massimo

    2011-10-01

    We discuss exotic properties of charged hydrodynamical systems, in the broken superconducting phase, probed by electromagnetic waves. Motivated by general arguments from hydrodynamics, we observe that negative refraction, namely the propagation in opposite directions of the phase velocities and of the energy flux, is expected for low enough frequencies. We corroborate this general idea by analyzing a holographic superconductor in the AdS/CFT correspondence, where the response functions can be explicitly computed. We study the dual gravitational theory both in the probe and in the backreacted case. We find that, while in the first case the refractive index is positive at every frequency, in the second case there is negative refraction at low enough frequencies. This is in agreement with hydrodynamic considerations.

  16. Radiation enteritis and radiation scoliosis

    SciTech Connect

    Shah, M.; Eng, K.; Engler, G.L.

    1980-09-01

    Any patient with radiation scoliosis should be suspected of having a visceral lesion as well. Chronic radiation enteritis may be manifested by intestinal obstruction, fistulas, perforation, and hemorrhage. Intestinal obstruction is the most common complication, and must be differentiated from postoperative cast or from spinal-traction syndrome. Obstruction that does not respond promptly to conservative measures must be treated surgically. Irradiated bowel is ischemic, and necrosis with spontaneous perforation can only be avoided with early diagnosis and surgical intervention.

  17. Radiation Therapy (For Parents)

    MedlinePlus

    ... Old Feeding Your 1- to 2-Year-Old Radiation Therapy KidsHealth > For Parents > Radiation Therapy Print A ... have many questions and concerns about it. About Radiation Therapy In radiation therapy, high-energy radiation from ...

  18. Abdominal radiation - discharge

    MedlinePlus

    Radiation - abdomen - discharge; Cancer - abdominal radiation; Lymphoma - abdominal radiation ... When you have radiation treatment for cancer, your body goes through changes. About 2 weeks after radiation treatment starts, you might notice changes ...

  19. Brain radiation - discharge

    MedlinePlus

    Radiation - brain - discharge; Cancer-brain radiation; Lymphoma - brain radiation; Leukemia - brain radiation ... Decadron) while you are getting radiation to the brain. It may make you hungrier, cause leg swelling ...

  20. Negative Emissions Technology

    NASA Astrophysics Data System (ADS)

    Day, Danny

    2006-04-01

    Although `negative emissions' of carbon dioxide need not, in principle, involve use of biological processes to draw carbon out of the atmosphere, such `agricultural' sequestration' is the only known way to remove carbon from the atmosphere on time scales comparable to the time scale for anthropogenic increases in carbon emissions. In order to maintain the `negative emissions' the biomass must be used in such a way that the resulting carbon dioxide is separated and permanently sequestered. Two options for sequestration are in the topsoil and via geologic carbon sequestration. The former has multiple benefits, but the latter also is needed. Thus, although geologic carbon sequestration is viewed skeptically by some environmentalists as simply a way to keep using fossil fuels---it may be a key part of reversing accelerating climate forcing if rapid climate change is beginning to occur. I will first review the general approach of agricultural sequestration combined with use of resulting biofuels in a way that permits carbon separation and then geologic sequestration as a negative emissions technology. Then I discuss the process that is the focus of my company---the EPRIDA cycle. If deployed at a sufficiently large scale, it could reverse the increase in CO2 concentrations. I also estimate of benefits --carbon and other---of large scale deployment of negative emissions technologies. For example, using the EPRIDA cycle by planting and soil sequestering carbon in an area abut In 3X the size of Texas would remove the amount of carbon that is being accumulated worldwide each year. In addition to the atmospheric carbon removal, the EPRIDA approach also counters the depletion of carbon in the soil---increasing topsoil and its fertility; reduces the excess nitrogen in the water by eliminating the need for ammonium nitrate fertilizer and reduces fossil fuel reliance by providing biofuel and avoiding natural gas based fertilizer production.

  1. Cosmic Tachyon Background Radiation

    NASA Astrophysics Data System (ADS)

    Tomaschitz, Roman

    The equilibrium statistical mechanics of a background radiation of superluminal particles is investigated, based on a vectorial wave equation for tachyons of the Proca type. The partition function, the spectral energy density, and the various thermodynamic variables of an ideal Bose gas of tachyons in an open Robertson-Walker cosmology are derived. The negative mass square in the wave equation changes the frequency scaling in the Rayleigh-Jeans law, and there are also significant changes in the low temperature regime as compared to the microwave background, in particular in the caloric and thermal equations of state.

  2. RADIATION INTEGRATOR

    DOEpatents

    Glass, F.M.; Wilson, H.N.

    1959-02-17

    Radiation detecting and measuring systems, particularly a compact, integrating, background monitor, are discussed. One of the principal features of the system is the use of an electrometer tube where the input of the tube is directly connected to an electrode of the radiation detector and a capacitor is coupled to the tube input. When a predetermined quantity of radiation has been integrated, a trigger signal is fed to a recorder and a charge is delivered to the capacitor to render the tube inoperative. The capacitor is then recharged for the next period of operation. With this arrangement there is a substantial reduction in lead lengths and the principal components may be enclosed and hermetically sealed to insure low leakage.

  3. Radiation effects.

    PubMed

    Preston, R J

    2012-01-01

    International Commission on Radiological Protection (ICRP) Committee 1 (C1) considers the risk of induction of cancer and heritable disease; the underlying mechanisms of radiation action; and the risks, severity, and mechanisms of induction of tissue reactions (formerly 'deterministic effects'). C1 relies upon the interpretation of current knowledge of radio-epidemiological studies; current information on the underlying mechanisms of diseases and radiation-induced disease; and current radiobiological studies at the whole animal, tissue, cell, and molecular levels. This overview will describe the activities of C1 in the context of the 2007 Recommendations of ICRP. In particular, the conclusions from the most recent C1 Task Group deliberations on radon and lung cancer, and tissue reactions will be discussed. Other activities are described in summary fashion to illustrate those areas that C1 judge to be likely to influence the development of the risk estimates and nominal risk coefficients used for radiation protection purposes.

  4. Radiation myelopathy.

    PubMed Central

    Sanyal, B; Pant, G C; Subrahmaniyam, K; Agrawal, M S; Mohanty, S

    1979-01-01

    Five cases of radiation myelopathy were found in a total of 10,000 cases given radiotherapy from 1968 to 1977. The clinical presentation and treatment details including the total dose, treatment volume, number of fractionations, overall time, and the RET value at the spinal cord were calculated and compared with other reports on this subject. The total number of fractionations ranged from 20 to 26 with an overall time of 32 days to 37 days. The dose received by four patients ranged from 1030 to 1900 RET, a little higher than the tolerance level of the spinal cord as compared to reported values. Two patients in this series had high blood pressure. The incidence of radiation myelopathy, already acceptably low, could possibly be reduced further by meticulous planning of radiation. PMID:448380

  5. Synchrotron radiation

    SciTech Connect

    Knotek, M.L.

    1987-01-01

    Synchrotron radiation has had a revolutionary effect on a broad range of scientific studies, from physics, chemistry and metallurgy to biology, medicine and geoscience. The situation during the last decade has been one of very rapid growth, there is a great vitality to the field and a capability has been given to a very broad range of scientific disciplines which was undreamed of just a decade or so ago. Here we will discuss some of the properties of synchrotron radiation that makes it so interesting and something of the sources in existence today including the National Synchrotron Light Source (NSLS). The NSLS is one of the new facilities built specifically for synchrotron radiation research and the model that was developed there for involvement of the scientific community is a good one which provides some good lessons for these facilities and others.

  6. Radiation receiver

    DOEpatents

    Hunt, A.J.

    1983-09-13

    The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles. 5 figs.

  7. Radiation receiver

    DOEpatents

    Hunt, Arlon J.

    1983-01-01

    The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles.

  8. Simulated 2050 aviation radiative forcing

    NASA Astrophysics Data System (ADS)

    Chen, C. C.; Gettelman, A.

    2015-12-01

    The radiative forcing from aviation is investigated by using a comprehensive general circulation model in the present (2006) and the future (2050). Global flight distance is projected to increase by a factor of 4 between 2006 and 2050. However, simulated contrail cirrus radiative forcing can increase by a factor of 7, and thus does not scale linearly with fuel emission mass. Simulations indicate negative radiative forcing induced by the indirect effect of aviation sulfate aerosols on liquid clouds that increasesby a factor of 4 in 2050. As a result, the net 2050 aviation radiative forcing is a cooling. Aviation sulfates emitted at cruise altitude canbe transported down to the lowest troposphere, increasing the aerosolconcentration, thus increasing the cloud drop number concentration and persistenceof low-level clouds. Aviation black carbon aerosols produce a negligible forcing.

  9. Directional radiation detectors

    DOEpatents

    Dowell, Jonathan L.

    2017-09-12

    Directional radiation detectors and systems, methods, and computer-readable media for using directional radiation detectors to locate a radiation source are provided herein. A directional radiation detector includes a radiation sensor. A radiation attenuator partially surrounds the radiation sensor and defines an aperture through which incident radiation is received by the radiation sensor. The aperture is positioned such that when incident radiation is received directly through the aperture and by the radiation sensor, a source of the incident radiation is located within a solid angle defined by the aperture. The radiation sensor senses at least one of alpha particles, beta particles, gamma particles, or neutrons.

  10. RADIATION SOURCES

    DOEpatents

    Brucer, M.H.

    1958-04-15

    A novel long-lived source of gamma radiation especially suitable for calibration purposes is described. The source of gamma radiation is denoted mock iodine131, which comprises a naixture of barium-133 and cesium-137. The barium and cesium are present in a barium-cesium ratio of approximately 5.7/1 to 14/1, uniformly dispersed in an ion exchange resin and a filter surrounding the resin comprised of a material of atomic number below approximately 51, and substantially 0.7 to 0.9 millimeter thick.

  11. (Radiation susceptibility)

    SciTech Connect

    Preston, R.J.

    1988-04-07

    The traveler was a participant in a workshop at RERF that was established to determine if current data or future studies could be utilized to address the question of whether radiation-sensitive individuals could have been over-represented in the A-bomb non-survivors in Hiroshima and Nagasaki and thereby affect the cancer incidences. The topic was addressed by presentations by RERF staff on their current studies pertinent to radiation susceptibility; round-table discussions among panel members and observers; a written series of recommendations prepared by the workshop members and presented to the RERF council.

  12. Radiation dermatitis

    SciTech Connect

    Shack, R.B.; Lynch, J.B.

    1987-04-01

    Even in this era of modern radiotherapy, injuries associated with the medical and industrial use of radiation devices will continue to pose a difficult problem for the reconstructive surgeon. It must be borne in mind that the single most serious hazard to surgery in irradiated tissue is the lodgement of bacteria in tissue rendered avascular by the radiation and the secondary necrosis from the infection itself. The basic principles of wound management must be augmented by thorough knowledge of the use of well-vascularized muscle and musculocutaneous flap to provide adequate, blood-rich, soft-tissue coverage.

  13. Reactions of Negative Ions

    DTIC Science & Technology

    1984-07-17

    AUTHOR(S)* Viggiano , Albert A., Paulson, John F. C 6 UPE E T R O A IOE 18ate SUBo EC TERMS enti t e "Swrme f Ionsar and Efyb l to n in Gases, FIELD...Reactions of Negative Ions Albert A. Viggiano * and John F. Paulson Air Force Geophysics Laboratory Hanscom AFB, Massachusetts 017310 *Air Force Geophysics...an important process in controlling the electron density in a variety of natural plasmas , such as the earth’s ionosphere and interstellar space, and

  14. Integrative Radiation Biology

    SciTech Connect

    Barcellos-Hoff, Mary Helen

    2015-02-27

    We plan to study tissue-level mechanisms important to human breast radiation carcinogenesis. We propose that the cell biology of irradiated tissues reveals a coordinated multicellular damage response program in which individual cell contributions are primarily directed towards suppression of carcinogenesis and reestablishment of homeostasis. We identified transforming growth factor β1 (TGFβ) as a pivotal signal. Notably, we have discovered that TGFβ suppresses genomic instability by controlling the intrinsic DNA damage response and centrosome integrity. However, TGFβ also mediates disruption of microenvironment interactions, which drive epithelial to mesenchymal transition in irradiated human mammary epithelial cells. This apparent paradox of positive and negative controls by TGFβ is the topic of the present proposal. First, we postulate that these phenotypes manifest differentially following fractionated or chronic exposures; second, that the interactions of multiple cell types in tissues modify the responses evident in this single cell type culture models. The goals are to: 1) study the effect of low dose rate and fractionated radiation exposure in combination with TGFβ on the irradiated phenotype and genomic instability of non-malignant human epithelial cells; and 2) determine whether stromal-epithelial interactions suppress the irradiated phenotype in cell culture and the humanized mammary mouse model. These data will be used to 3) develop a systems biology model that integrates radiation effects across multiple levels of tissue organization and time. Modeling multicellular radiation responses coordinated via extracellular signaling could have a significant impact on the extrapolation of human health risks from high dose to low dose/rate radiation exposure.

  15. Spacecraft Electrostatic Radiation Shielding

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This project analyzed the feasibility of placing an electrostatic field around a spacecraft to provide a shield against radiation. The concept was originally proposed in the 1960s and tested on a spacecraft by the Soviet Union in the 1970s. Such tests and analyses showed that this concept is not only feasible but operational. The problem though is that most of this work was aimed at protection from 10- to 100-MeV radiation. We now appreciate that the real problem is 1- to 2-GeV radiation. So, the question is one of scaling, in both energy and size. Can electrostatic shielding be made to work at these high energy levels and can it protect an entire vehicle? After significant analysis and consideration, an electrostatic shield configuration was proposed. The selected architecture was a torus, charged to a high negative voltage, surrounding the vehicle, and a set of positively charged spheres. Van de Graaff generators were proposed as the mechanism to move charge from the vehicle to the torus to generate the fields necessary to protect the spacecraft. This design minimized complexity, residual charge, and structural forces and resolved several concerns raised during the internal critical review. But, it still is not clear if such a system is costeffective or feasible, even though several studies have indicated usefulness for radiation protection at energies lower than that of the galactic cosmic rays. Constructing such a system will require power supplies that can generate voltages 10 times that of the state of the art. Of more concern is the difficulty of maintaining the proper net charge on the entire structure and ensuring that its interaction with solar wind will not cause rapid discharge. Yet, if these concerns can be resolved, such a scheme may provide significant radiation shielding to future vehicles, without the excessive weight or complexity of other active shielding techniques.

  16. Polarized negative ions

    SciTech Connect

    Haeberli, W.

    1981-04-01

    This paper presents a survey of methods, commonly in use or under development, to produce beams of polarized negative ions for injection into accelerators. A short summary recalls how the hyperfine interaction is used to obtain nuclear polarization in beams of atoms. Atomic-beam sources for light ions are discussed. If the best presently known techniques are incorporated in all stages of the source, polarized H/sup -/ and D/sup -/ beams in excess of 10 ..mu..A can probably be achieved. Production of polarized ions from fast (keV) beams of polarized atoms is treated separately for atoms in the H(25) excited state (Lamb-Shift source) and atoms in the H(1S) ground state. The negative ion beam from Lamb-Shift sources has reached a plateau just above 1 ..mu..A, but this beam current is adequate for many applications and the somewhat lower beam current is compensated by other desirable characteristics. Sources using fast polarized ground state atoms are in a stage of intense development. The next sections summarize production of polarized heavy ions by the atomic beam method, which is well established, and by optical pumping, which has recently been demonstrated to yield very large nuclear polarization. A short discussion of proposed ion sources for polarized /sup 3/He/sup -/ ions is followed by some concluding remarks.

  17. Negative magnetoresistivity in holography

    NASA Astrophysics Data System (ADS)

    Sun, Ya-Wen; Yang, Qing

    2016-09-01

    Negative magnetoresistivity is a special magnetotransport property associated with chiral anomaly in four dimensional chiral anomalous systems, which refers to the transport behavior that the DC longitudinal magnetoresistivity decreases with increasing magnetic field. We calculate the longitudinal magnetoconductivity in the presence of back-reactions of the magnetic field to gravity in holographic zero charge and axial charge density systems with and without axial charge dissipation. In the absence of axial charge dissipation, we find that the quantum critical conductivity grows with increasing magnetic field when the backreaction strength is larger than a critical value, in contrast to the monotonically decreasing behavior of quantum critical conductivity in the probe limit. With axial charge dissipation, we find the negative magnetoresistivity behavior. The DC longitudinal magnetoconductivity scales as B in the large magnetic field limit, which deviates from the exact B 2 scaling of the probe limit result. In both cases, the small frequency longitudinal magnetoconductivity still agrees with the formula obtained from the hydrodynamic linear response theory, even in the large magnetic field limit.

  18. Acoustic radiation force control: Pulsating spherical carriers.

    PubMed

    Rajabi, Majid; Mojahed, Alireza

    2017-06-13

    The interaction between harmonic plane progressive acoustic beams and a pulsating spherical radiator is studied. The acoustic radiation force function exerted on the spherical body is derived as a function of the incident wave pressure and the monopole vibration characteristics (i.e., amplitude and phase) of the body. Two distinct strategies are presented in order to alter the radiation force effects (i.e., pushing and pulling states) by changing its magnitude and direction. In the first strategy, an incident wave field with known amplitude and phase is considered. It is analytically shown that the zero- radiation force state (i.e., radiation force function cancellation) is achievable for specific pulsation characteristics belong to a frequency-dependent straight line equation in the plane of real-imaginary components (i.e., Nyquist Plane) of prescribed surface displacement. It is illustrated that these characteristic lines divide the mentioned displacement plane into two regions of positive (i.e., pushing) and negative (i.e., pulling) radiation forces. In the second strategy, the zero, negative and positive states of radiation force are obtained through adjusting the incident wave field characteristics (i.e., amplitude and phase) which insonifies the radiator with prescribed pulsation characteristics. It is proved that zero radiation force state occurs for incident wave pressure characteristics belong to specific frequency-dependent circles in Nyquist plane of incident wave pressure. These characteristic circles divide the Nyquist plane into two distinct regions corresponding to positive (out of circles) and negative (in the circles) values of radiation force function. It is analytically shown that the maximum amplitude of negative radiation force is exactly equal to the amplitude of the (positive) radiation force exerted upon the sphere in the passive state, by the same incident field. The developed concepts are much more deepened by considering the required

  19. Radiation Insulation

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Radiation insulation technology from Apollo and subsequent spacecraft was used to develop superinsulators, used by makers of cold weather apparel, to make parkas, jackets, boots and outdoor gear such as sleeping bags. The radiant barrier technology offers warmth retention at minimal weight and bulk.

  20. Radiation Models

    ERIC Educational Resources Information Center

    James, W. G. G.

    1970-01-01

    Discusses the historical development of both the wave and the corpuscular photon model of light. Suggests that students should be informed that the two models are complementary and that each model successfully describes a wide range of radiation phenomena. Cites 19 references which might be of interest to physics teachers and students. (LC)

  1. Radiation Insulation

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Radiation insulation technology from Apollo and subsequent spacecraft was used to develop superinsulators, used by makers of cold weather apparel, to make parkas, jackets, boots and outdoor gear such as sleeping bags. The radiant barrier technology offers warmth retention at minimal weight and bulk.

  2. Radiation accidents

    SciTech Connect

    Saenger, E.L.

    1986-09-01

    It is essential that emergency physicians understand ways to manage patients contaminated by radioactive materials and/or exposed to external radiation sources. Contamination accidents require careful surveys to identify the metabolic pathway of the radionuclides to guide prognosis and treatment. The level of treatment required will depend on careful surveys and meticulous decontamination. There is no specific therapy for the acute radiation syndrome. Prophylactic antibodies are desirable. For severely exposed patients treatment is similar to the supportive care given to patients undergoing organ transplantation. For high-dose extremity injury, no methods have been developed to reverse the fibrosing endarteritis that eventually leads to tissue death so frequently found with this type of injury. Although the Three Mile Island episode of March 1979 created tremendous public concern, there were no radiation injuries. The contamination outside the reactor building and the release of radioiodine were negligible. The accidental fuel element meltdown at Chernobyl, USSR, resulted in many cases of acute radiation syndrome. More than 100,000 people were exposed to high levels of radioactive fallout. The general principles outlined here are applicable to accidents of that degree of severity.

  3. Ionizing radiation

    USDA-ARS?s Scientific Manuscript database

    This chapter gives a comprehensive review on ionizing irradiation of fresh fruits and vegetables. Topics include principles of ionizing radiation, its effects on pathogenic and spoilage microorganisms, shelf-life, sensory quality, nutritional and phytochemical composition, as well as physiologic and...

  4. Radiation Models

    ERIC Educational Resources Information Center

    James, W. G. G.

    1970-01-01

    Discusses the historical development of both the wave and the corpuscular photon model of light. Suggests that students should be informed that the two models are complementary and that each model successfully describes a wide range of radiation phenomena. Cites 19 references which might be of interest to physics teachers and students. (LC)

  5. Classroom Management and Negative Reinforcement.

    ERIC Educational Resources Information Center

    Tauber, Robert T.

    Of the four simple consequences for behavior, none is more misunderstood than negative reinforcement. A Negative Reinforcement Quiz administered to 233 student teachers from two universities revealed that the vast majority of respondents mistakenly viewed negative reinforcement as a synonym for punishment, and believe that negative reinforcement…

  6. Double-negative acoustic metamaterial.

    PubMed

    Li, Jensen; Chan, C T

    2004-11-01

    We show here the existence of acoustic metamaterial, in which both the effective density and bulk modulus are simultaneously negative, in the true and strict sense of an effective medium. Our double-negative acoustic system is an acoustic analogue of Veselago's medium in electromagnetism, and shares many unique consequences, such as negative refractive index. The double negativity in acoustics is derived from low-frequency resonances, as in the case of electromagnetism, but the negative density and modulus are derived from a single resonance structure as distinct from electromagnetism in which the negative permeability and negative permittivity originates from different resonance mechanisms.

  7. Avoiding Negative Dysphagia Outcomes.

    PubMed

    Tanner, Dennis C; Culbertson, William R

    2014-04-23

    Dysphagia in adults affects their quality of life and can lead to life-threatening conditions. The authors draw on both 30 years of experience as clinicians and also on expert testimony in adult, dysphagia-malpractice cases to make five recommendations with the aim of preventing dysphagia-related deaths. They discuss the importance of informed consent documents and suggest the following nursing actions to reduce these often unnecessary tragedies: consider the importance of diet status; understand and follow speech-language-pathologists' recommendations; be familiar with the dysphagia assessment; be responsive to the need for an instrumental assessment; and ensure dysphagia communication is accurate and disseminated among healthcare professionals. They conclude that most negative dysphagia-management outcomes can be prevented and that nurses play a pivotal role in this prevention.

  8. Negative optical torque.

    PubMed

    Chen, Jun; Ng, Jack; Ding, Kun; Fung, Kin Hung; Lin, Zhifang; Chan, C T

    2014-09-17

    Light carries angular momentum, and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful and versatile after the invention of laser. Novel and practical approaches for harvesting light for particle rotation have since been demonstrated, where the structure is always subjected to a positive optical torque along a certain axis if the incident angular momentum has a positive projection on the same axis. We report here an interesting phenomenon of "negative optical torque", meaning that incoming photons carrying angular momentum rotate an object in the opposite sense. Surprisingly this can be realized quite straightforwardly in simple planar structures. Field retardation is a necessary condition and discrete rotational symmetry of material object plays an important role. The optimal conditions are explored and explained.

  9. Negative Entropy of Life

    NASA Astrophysics Data System (ADS)

    Goradia, Shantilal

    2015-10-01

    We modify Newtonian gravity to probabilistic quantum mechanical gravity to derive strong coupling. If this approach is valid, we should be able to extend it to the physical body (life) as follows. Using Boltzmann equation, we get the entropy of the universe (137) as if its reciprocal, the fine structure constant (ALPHA), is the hidden candidate representing the negative entropy of the universe which is indicative of the binary information as its basis (http://www.arXiv.org/pdf/physics0210040v5). Since ALPHA relates to cosmology, it must relate to molecular biology too, with the binary system as the fundamental source of information for the nucleotides of the DNA as implicit in the book by the author: ``Quantum Consciousness - The Road to Reality.'' We debate claims of anthropic principle based on the negligible variation of ALPHA and throw light on thermodynamics. We question constancy of G in multiple ways.

  10. Negative Optical Torque

    NASA Astrophysics Data System (ADS)

    Chen, Jun; Ng, Jack; Ding, Kun; Fung, Kin Hung; Lin, Zhifang; Chan, C. T.

    2014-09-01

    Light carries angular momentum, and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful and versatile after the invention of laser. Novel and practical approaches for harvesting light for particle rotation have since been demonstrated, where the structure is always subjected to a positive optical torque along a certain axis if the incident angular momentum has a positive projection on the same axis. We report here an interesting phenomenon of ``negative optical torque'', meaning that incoming photons carrying angular momentum rotate an object in the opposite sense. Surprisingly this can be realized quite straightforwardly in simple planar structures. Field retardation is a necessary condition and discrete rotational symmetry of material object plays an important role. The optimal conditions are explored and explained.

  11. Negative ion source

    DOEpatents

    Leung, K.N.; Ehlers, K.W.

    1982-08-06

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

  12. Negative ion source

    DOEpatents

    Leung, K.N.; Ehlers, K.W.

    1984-12-04

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field. 14 figs.

  13. Negative Optical Torque

    PubMed Central

    Chen, Jun; Ng, Jack; Ding, Kun; Fung, Kin Hung; Lin, Zhifang; Chan, C. T.

    2014-01-01

    Light carries angular momentum, and as such it can exert torques on material objects. Applications of these opto-mechanical effects were limited initially due to their smallness in magnitude, but later becomes powerful and versatile after the invention of laser. Novel and practical approaches for harvesting light for particle rotation have since been demonstrated, where the structure is always subjected to a positive optical torque along a certain axis if the incident angular momentum has a positive projection on the same axis. We report here an interesting phenomenon of “negative optical torque”, meaning that incoming photons carrying angular momentum rotate an object in the opposite sense. Surprisingly this can be realized quite straightforwardly in simple planar structures. Field retardation is a necessary condition and discrete rotational symmetry of material object plays an important role. The optimal conditions are explored and explained. PMID:25226863

  14. Negative ion source

    DOEpatents

    Leung, Ka-Ngo; Ehlers, Kenneth W.

    1984-01-01

    An ionization vessel is divided into an ionizing zone and an extraction zone by a magnetic filter. The magnetic filter prevents high-energy electrons from crossing from the ionizing zone to the extraction zone. A small positive voltage impressed on a plasma grid, located adjacent an extraction grid, positively biases the plasma in the extraction zone to thereby prevent positive ions from migrating from the ionizing zone to the extraction zone. Low-energy electrons, which would ordinarily be dragged by the positive ions into the extraction zone, are thereby prevented from being present in the extraction zone and being extracted along with negative ions by the extraction grid. Additional electrons are suppressed from the output flux using ExB drift provided by permanent magnets and the extractor grid electrical field.

  15. Do `negative' temperatures exist?

    NASA Astrophysics Data System (ADS)

    Lavenda, B. H.

    1999-06-01

    A modification of the second law is required for a system with a bounded density of states and not the introduction of a `negative' temperature scale. The ascending and descending branches of the entropy versus energy curve describe particle and hole states, having thermal equations of state that are given by the Fermi and logistic distributions, respectively. Conservation of energy requires isentropic states to be isothermal. The effect of adiabatically reversing the field is entirely mechanical because the only difference between the two states is their energies. The laws of large and small numbers, leading to the normal and Poisson approximations, characterize statistically the states of infinite and zero temperatures, respectively. Since the heat capacity also vanishes in the state of maximum disorder, the third law can be generalized in systems with a bounded density of states: the entropy tends to a constant as the temperature tends to either zero or infinity.

  16. Radiation Therapy: Professions in Radiation Therapy

    MedlinePlus

    ... and typically one to two years of clinical physics training. They are certified by the American Board of Radiology or the American Board of Medical Physics . Radiation Therapist Radiation therapists work with radiation oncologists. ...

  17. Radiation Engineering for Designers

    NASA Technical Reports Server (NTRS)

    Pellish, Jonathan A.

    2015-01-01

    This tutorial provides an overview of the natural space radiation environment, an introduction to radiation effect types, an overview of EEE parts selection, scrubbing, and radiation mitigation, and an introduction to radiation testing.

  18. Radiation Engineering for Designers

    NASA Technical Reports Server (NTRS)

    Pellish, Jonathan A.

    2015-01-01

    This tutorial provides an overview of the natural space radiation environment, an introduction to radiation effect types, an overview of EEE parts selection, scrubbing, and radiation mitigation, and an introduction to radiation testing.

  19. Risk Factors: Radiation

    Cancer.gov

    Radiation of certain wavelengths, called ionizing radiation, has enough energy to damage DNA and cause cancer. Ionizing radiation includes radon, x-rays, gamma rays, and other forms of high-energy radiation.

  20. Negative Expertise: Comparing Differently Tenured Elder Care Nurses' Negative Knowledge

    ERIC Educational Resources Information Center

    Gartmeier, Martin; Lehtinen, Erno; Gruber, Hans; Heid, Helmut

    2011-01-01

    Negative expertise is conceptualised as the professional's ability to avoid errors during practice due to certain cognitive agencies. In this study, negative knowledge (i.e. knowledge about what is wrong in a certain context and situation) is conceptualised as one such agency. This study compares and investigates the negative knowledge of elder…

  1. Coagulase-Negative Staphylococci

    PubMed Central

    Heilmann, Christine; Peters, Georg

    2014-01-01

    SUMMARY The definition of the heterogeneous group of coagulase-negative staphylococci (CoNS) is still based on diagnostic procedures that fulfill the clinical need to differentiate between Staphylococcus aureus and those staphylococci classified historically as being less or nonpathogenic. Due to patient- and procedure-related changes, CoNS now represent one of the major nosocomial pathogens, with S. epidermidis and S. haemolyticus being the most significant species. They account substantially for foreign body-related infections and infections in preterm newborns. While S. saprophyticus has been associated with acute urethritis, S. lugdunensis has a unique status, in some aspects resembling S. aureus in causing infectious endocarditis. In addition to CoNS found as food-associated saprophytes, many other CoNS species colonize the skin and mucous membranes of humans and animals and are less frequently involved in clinically manifested infections. This blurred gradation in terms of pathogenicity is reflected by species- and strain-specific virulence factors and the development of different host-defending strategies. Clearly, CoNS possess fewer virulence properties than S. aureus, with a respectively different disease spectrum. In this regard, host susceptibility is much more important. Therapeutically, CoNS are challenging due to the large proportion of methicillin-resistant strains and increasing numbers of isolates with less susceptibility to glycopeptides. PMID:25278577

  2. Negative ion source

    DOEpatents

    Delmore, James E.

    1987-01-01

    A method and apparatus for providing a negative ion source accelerates electrons away from a hot filament electron emitter into a region of crossed electric and magnetic fields arranged in a magnetron configuration. During a portion of the resulting cycloidal path, the electron velocity is reduced below its initial value. The electron accelerates as it leaves the surface at a rate of only slightly less than if there were no magnetic field, thereby preventing a charge buildup at the surface of the emitter. As the electron traverses the cycloid, it is decelerated during the second, third, and fourth quadrants, then reeccelerated as it approaches the end of the fourth quadrant to regain its original velocity. The minimum velocity occurs during the fourth quadrant, and corresponds to an electron temperature of 200.degree. to 500.degree. for the electric and magnetic fields commonly encountered in the ion sources of magnetic sector mass spectrometers. An ion source using the above-described thermalized electrons is also disclosed.

  3. Coagulase-negative staphylococci.

    PubMed

    Becker, Karsten; Heilmann, Christine; Peters, Georg

    2014-10-01

    The definition of the heterogeneous group of coagulase-negative staphylococci (CoNS) is still based on diagnostic procedures that fulfill the clinical need to differentiate between Staphylococcus aureus and those staphylococci classified historically as being less or nonpathogenic. Due to patient- and procedure-related changes, CoNS now represent one of the major nosocomial pathogens, with S. epidermidis and S. haemolyticus being the most significant species. They account substantially for foreign body-related infections and infections in preterm newborns. While S. saprophyticus has been associated with acute urethritis, S. lugdunensis has a unique status, in some aspects resembling S. aureus in causing infectious endocarditis. In addition to CoNS found as food-associated saprophytes, many other CoNS species colonize the skin and mucous membranes of humans and animals and are less frequently involved in clinically manifested infections. This blurred gradation in terms of pathogenicity is reflected by species- and strain-specific virulence factors and the development of different host-defending strategies. Clearly, CoNS possess fewer virulence properties than S. aureus, with a respectively different disease spectrum. In this regard, host susceptibility is much more important. Therapeutically, CoNS are challenging due to the large proportion of methicillin-resistant strains and increasing numbers of isolates with less susceptibility to glycopeptides.

  4. Improved negative ion source

    DOEpatents

    Delmore, J.E.

    1984-05-01

    A method and apparatus for providing a negative ion source accelerates electrons away from a hot filament electron emitter into a region of crossed electric and magnetic fields arranged in a magnetron configuration. During a portion of the resulting cycloidal path, the electron velocity is reduced below its initial value. The electron accelerates as it leaves the surface at a rate of only slightly less than if there were no magnetic field, thereby preventing a charge buildup at the surface of the emitter. As the electron traverses the cycloid, it is decelerated during the second, third, and fourth quadrants, then reaccelerated as it approaches the end of the fourth quadrant to regain its original velocity. The minimum velocity occurs during the fourth quadrant, and corresponds to an electron temperature of 200 to 500/sup 0/C for the electric and magnetic fields commonly encountered in the ion sources of magnetic sector mass spectrometers. An ion source using the above-described thermalized electrons is also disclosed.

  5. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. TOP OF BEVATRON, BUILDING 51 ROOF TRUSS, AND CENTRAL RING TRACK FOR MAGNET ROOM CRANE, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  6. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. STAIRWAY FROM MAIN FLOOR OF MAGNET ROOM TO TOP OF OUTER LAYER OF CONCRETE SHIELDING, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  7. Photocopy of photograph (original negative located in LBNL Photo Lab ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (original negative located in LBNL Photo Lab Collection). March 2005. STAIRWAY BETWEEN MAIN FLOOR OF MAGNET ROOM AND SECOND FLOOR OF OFFICE-AND-SHOP SECTION, BEVATRON - University of California Radiation Laboratory, Bevatron, 1 Cyclotron Road, Berkeley, Alameda County, CA

  8. Negative Pressure Wound Therapy

    PubMed Central

    2006-01-01

    Executive Summary Objective This review was conducted to assess the effectiveness of negative pressure wound therapy. Clinical Need: Target Population and Condition Many wounds are difficult to heal, despite medical and nursing care. They may result from complications of an underlying disease, like diabetes; or from surgery, constant pressure, trauma, or burns. Chronic wounds are more often found in elderly people and in those with immunologic or chronic diseases. Chronic wounds may lead to impaired quality of life and functioning, to amputation, or even to death. The prevalence of chronic ulcers is difficult to ascertain. It varies by condition and complications due to the condition that caused the ulcer. There are, however, some data on condition-specific prevalence rates; for example, of patients with diabetes, 15% are thought to have foot ulcers at some time during their lives. The approximate community care cost of treating leg ulcers in Canada, without reference to cause, has been estimated at upward of $100 million per year. Surgically created wounds can also become chronic, especially if they become infected. For example, the reported incidence of sternal wound infections after median sternotomy is 1% to 5%. Abdominal surgery also creates large open wounds. Because it is sometimes necessary to leave these wounds open and allow them to heal on their own (secondary intention), some may become infected and be difficult to heal. Yet, little is known about the wound healing process, and this makes treating wounds challenging. Many types of interventions are used to treat wounds. Current best practice for the treatment of ulcers and other chronic wounds includes debridement (the removal of dead or contaminated tissue), which can be surgical, mechanical, or chemical; bacterial balance; and moisture balance. Treating the cause, ensuring good nutrition, and preventing primary infection also help wounds to heal. Saline or wet-to-moist dressings are reported as

  9. Negative Ions in Space.

    PubMed

    Millar, Thomas J; Walsh, Catherine; Field, Thomas A

    2017-02-08

    Until a decade ago, the only anion observed to play a prominent role in astrophysics was H(-). The bound-free transitions in H(-) dominate the visible opacity in stars with photospheric temperatures less than 7000 K, including the Sun. The H(-) anion is also believed to have been critical to the formation of molecular hydrogen in the very early evolution of the Universe. Once H2 formed, about 500 000 years after the Big Bang, the expanding gas was able to lose internal gravitational energy and collapse to form stellar objects and "protogalaxies", allowing the creation of heavier elements such as C, N, and O through nucleosynthesis. Although astronomers had considered some processes through which anions might form in interstellar clouds and circumstellar envelopes, including the important role that polycyclic aromatic hydrocarbons might play in this, it was the detection in 2006 of rotational line emission from C6H(-) that galvanized a systematic study of the abundance, distribution, and chemistry of anions in the interstellar medium. In 2007, the Cassini mission reported the unexpected detection of anions with mass-to-charge ratios of up to ∼10 000 in the upper atmosphere of Titan; this observation likewise instigated the study of fundamental chemical processes involving negative ions among planetary scientists. In this article, we review the observations of anions in interstellar clouds, circumstellar envelopes, Titan, and cometary comae. We then discuss a number of processes by which anions can be created and destroyed in these environments. The derivation of accurate rate coefficients for these processes is an essential input for the chemical kinetic modeling that is necessary to fully extract physics from the observational data. We discuss such models, along with their successes and failings, and finish with an outlook on the future.

  10. Negative results: negative perceptions limit their potential for increasing reproducibility.

    PubMed

    Teixeira da Silva, Jaime A

    2015-07-07

    Negative results are an important building block in the development of scientific thought, primarily because most likely the vast majority of data is negative, i.e., there is not a favorable outcome. Only very limited data is positive, and that is what tends to get published, albeit alongside a sub-set of negative results to emphasize the positive nature of the positive results. Yet, not all negative results get published. Part of the problem lies with a traditional mind-set and rigid publishing frame-work that tends to view negative results in a negative light, or that only tends to reward scientists primarily for presenting positive findings. This opinion piece indicates that in addition to a deficient mind-set, there are also severe limitations in the availability of publishing channels where negative results could get published.

  11. Negative Association in Quebec French.

    ERIC Educational Resources Information Center

    Larrivee, Pierre

    In Quebec French, unlike standard French, sentence negation "pas" ("not") can occur in the same clause as a negative quantifier like "personne" ("nobody"), for instance. This paper proposes that "pas" in these contexts marks negative association in the same way that "ne" does in standard…

  12. Survey on radiation safety management (RSM) among Korean radiation workers who operate radiation generators or handle radioactive isotopes.

    PubMed

    Ryu, Young-Hwan; Cho, Jae-Hwan; Dong, Kyung-Rae; Chung, Woon-Kwan; Lee, Jong-Woong; Choi, Eun-Jin

    2014-01-01

    This study examined the knowledge, attitudes, and behaviors of radiation workers to radiation safety management (RSM) using survey questionnaires. Radiation workers are those who handle radiation generators, radioactive isotopes, and other radioactive materials for industrial uses. The survey was distributed to 861 radiation workers between 1 August to 5 September 2011. A knowledge of, awareness of, attitude toward, and behaviors related to RSM were analyzed by comparing the means and standard deviations. Both the knowledge and awareness of RSM among radiation workers were high. Although all questions about the awareness of RSM were answered correctly, there were also many negative responses. All questions regarding the attitude of radiation workers toward RSM were answered correctly, and their attitude toward and awareness of RSM were high. Overall, the results demonstrated that safety management is not taken seriously in many cases, highlighting the need for proper education in the future to raise awareness among radiation workers. Furthermore, it is important to establish a foundation for the efficient use of radiation based on the continuous management of radiation workers.

  13. Shortwave Radiation

    NASA Technical Reports Server (NTRS)

    Klassen, Steve; Bugbee, Bruce

    2005-01-01

    Accurate shortwave radiation data is critical to evapotranspiration (ET) models used for developing irrigation schedules to optimize crop production while saving water, minimizing fertilizer, herbicide, and pesticide applications, reducing soil erosion, and protecting surface and ground water quality. Low cost silicon cell pyranometers have proven to be sufficiently accurate and robust for widespread use in agricultural applications under unobstructed daylight conditions. More expensive thermopile pyranometers are required for use as calibration standards and measurements under light with unique spectral properties (electric lights, under vegetation, in greenhouses and growth chambers). Routine cleaning, leveling, and annual calibration checks will help to ensure the integrity of long-term data.

  14. Shortwave Radiation

    NASA Technical Reports Server (NTRS)

    Klassen, Steve; Bugbee, Bruce

    2005-01-01

    Accurate shortwave radiation data is critical to evapotranspiration (ET) models used for developing irrigation schedules to optimize crop production while saving water, minimizing fertilizer, herbicide, and pesticide applications, reducing soil erosion, and protecting surface and ground water quality. Low cost silicon cell pyranometers have proven to be sufficiently accurate and robust for widespread use in agricultural applications under unobstructed daylight conditions. More expensive thermopile pyranometers are required for use as calibration standards and measurements under light with unique spectral properties (electric lights, under vegetation, in greenhouses and growth chambers). Routine cleaning, leveling, and annual calibration checks will help to ensure the integrity of long-term data.

  15. Negative ions in liquid helium

    NASA Astrophysics Data System (ADS)

    Khrapak, A. G.; Schmidt, W. F.

    2011-05-01

    The structure of negative ions in liquid 4He is analyzed. The possibility of cluster or bubble formation around impurity ions of both signs is discussed. It is shown that in superfluid helium, bubbles form around negative alkaline earth metal ions and clusters form around halogen ions. The nature of "fast" and "exotic" negative ions is also discussed. It is assumed that "fast" ions are negative ions of helium excimer molecules localized inside bubbles. "Exotic" ions are stable negative impurity ions, which are always present in small amounts in gas discharge plasmas. Bubbles or clusters with radii smaller the radius of electron bubbles develop around these ions.

  16. Double-Negative Mechanical Metamaterials Displaying Simultaneous Negative Stiffness and Negative Poisson's Ratio Properties.

    PubMed

    Hewage, Trishan A M; Alderson, Kim L; Alderson, Andrew; Scarpa, Fabrizio

    2016-12-01

    A scalable mechanical metamaterial simultaneously displaying negative stiffness and negative Poisson's ratio responses is presented. Interlocking hexagonal subunit assemblies containing 3 alternative embedded negative stiffness (NS) element types display Poisson's ratio values of -1 and NS values over two orders of magnitude (-1.4 N mm(-1) to -160 N mm(-1) ), in good agreement with model predictions.

  17. The negation bias: when negations signal stereotypic expectancies.

    PubMed

    Beukeboom, Camiel J; Finkenauer, Catrin; Wigboldus, Daniël H J

    2010-12-01

    Research on linguistic biases shows that stereotypic expectancies are implicitly reflected in language and are thereby subtly communicated to message recipients. We examined whether these findings extend to the use of negations (e.g., not smart instead of stupid). We hypothesized that people use more negations in descriptions of stereotype-inconsistent behavior than in descriptions of stereotype-consistent behavior. In 3 studies, participants either judged the applicability of experimentally controlled person descriptions or spontaneously produced person descriptions themselves. Results provided support for this hypothesis. Moreover, a 4th study demonstrated that negations have communicative consequences. When a target person's behavior was described with negations, message recipients inferred that this behavior was an exception to the rule and that it was more likely caused by situational circumstances than by dispositional factors. These findings indicate that by using negations people implicitly communicate stereotypic expectancies and that negations play a subtle but powerful role in stereotype maintenance.

  18. An exposition on Friedmann cosmology with negative energy densities

    SciTech Connect

    Nemiroff, Robert J.; Joshi, Ravi; Patla, Bijunath R. E-mail: rjoshimtu@gmail.com

    2015-06-01

    How would negative energy density affect a classic Friedmann cosmology? Although never measured and possibly unphysical, certain realizations of quantum field theories leaves the door open for such a possibility. In this paper we analyze the evolution of a universe comprising varying amounts of negative energy forms. Negative energy components have negative normalized energy densities, Ω < 0. They include negative phantom energy with an equation of state parameter w < −1, negative cosmological constant: w=−1, negative domain walls: w = −2/3, negative cosmic strings: w=−1/3, negative mass: w = 0, negative radiation: w = 1/3 and negative ultralight: w > 1/3. Assuming that such energy forms generate pressure like perfect fluids, the attractive or repulsive nature of negative energy components are reviewed. The Friedmann equation is satisfied only when negative energy forms are coupled to a greater magnitude of positive energy forms or positive curvature. We show that the solutions exhibit cyclic evolution with bounces and turnovers.The future and fate of such universes in terms of curvature, temperature, acceleration, and energy density are reviewed. The end states are dubbed ''big crunch,' '' big void,' or ''big rip' and further qualified as ''warped',''curved', or ''flat',''hot' versus ''cold', ''accelerating' versus ''decelerating' versus ''coasting'. A universe that ends by contracting to zero energy density is termed ''big poof.' Which contracting universes ''bounce' in expansion and which expanding universes ''turnover' into contraction are also reviewed.

  19. Compound negative binomial distribution with negative multinomial summands

    NASA Astrophysics Data System (ADS)

    Jordanova, Pavlina K.; Petkova, Monika P.; Stehlík, Milan

    2016-12-01

    The class of Negative Binomial distributions seems to be introduced by Greenwood and Yule in 1920. Due to its wide spread application, investigations of distributions, closely related with it will be always contemporary. Bates, Neyman and Wishart introduce Negative Multinomial distribution. They reach it considering the mixture of independent Poisson distributed random variables with one and the same Gamma mixing variable. This paper investigates a particular case of multivariate compound distribution with one and the same compounding variable. In our case it is Negative Binomial or Sifted Negative Binomial. The summands with equal indexes in different coordinates are Negative Multinomially distributed. In case without shifting, considered as a mixture, the resulting distribution coincides with Mixed Negative Multinomial distribution with scale changed Negative Binomially distributed first parameter. We prove prove that it is Multivariate Power Series Distributed and find explicit form of its parameters. When the summands are geometrically distributed this distribution is stochastically equivalent to a product of independent Bernoulli random variable and appropriate multivariate Geometrically distributed random vector. We show that Compound Shifted Negative Binomial Distribution with Geometric Summands is a particular case of Negative Multinomial distribution with new parameters.

  20. RADIATION DOSIMETER

    DOEpatents

    Balkwell, W.R. Jr.; Adams, G.D. Jr.

    1960-05-10

    An improvement was made in the determination of amounts of ionizing radiation, particularly low-energy beta particles of less than 1000 rad total dose by means of fluid-phase dosimeter employing a stabilized-- sensitized ferrous-ferric colorimetric system in a sulphuric acid medium. The improvement in the dosimeter consists of adding to the ferrous-ferric system in concentrations of 10/sub -2/ to 10/sup -4/M an organic compound having one or more carboxylic or equivalent groups, such compounds being capable of chelating or complexing the iron ions in the solution. Suitable sensitizing and stabilizing agents are benzoic, phthalic, salicylic, malonic, lactic, maleic, oxalic, citric, succinic, phenolic tartaric, acetic, and adipic acid, as well as other compounds which are added to the solution alone or in certain combinations. As in conventional fluid-phase dosimeters, the absorbed dosage is correlated with a corresponding change in optical density at particular wavelengths of the solution.

  1. RADIATION COUNTER

    DOEpatents

    Goldsworthy, W.W.

    1958-02-01

    This patent relates to a radiation counter, and more particularly, to a scintillation counter having high uniform sensitivity over a wide area and capable of measuring alpha, beta, and gamma contamination over wide energy ranges, for use in quickly checking the contami-nation of personnel. Several photomultiplier tubes are disposed in parallel relationship with a light tight housing behind a wall of scintillation material. Mounted within the housing with the photomultipliers are circuit means for producing an audible sound for each pulse detected, and a range selector developing a voltage proportional to the repetition rate of the detected pulses and automatically altering its time constant when the voltage reaches a predetermined value, so that manual range adjustment of associated metering means is not required.

  2. Radiation Insulation

    NASA Technical Reports Server (NTRS)

    1993-01-01

    An aluminized polymer film is a highly effective radiation barrier for both manned and unmanned spacecraft. Variations of this space-devised material are also used as an energy conservation technique for homes and offices. One commercial company, Tech 2000 (formerly Buckeye Radiant Barrier), markets 'Super R' Radiant Barrier, which finds its origins in the Apollo Mission programs. The material is placed between wall studs and exterior facing before siding or in new roof installation, between roof support and roof sheathing. Successful retrofit installations have included schools and shrink wrap ovens. The radiant barrier blocks 95 percent of radiant energy, thus retaining summer heat and blocking winter cold. Suppliers claim utility bill reductions of 20 percent or more.

  3. Radiation Insulation

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Apollo and subsequent spacecraft have had highly effective radiation barriers; made of aluminized polymer film, they bar or let in heat to maintain consistent temperatures inside. Tech 2000, formerly Quantum International Corporation used the NASA technology in its insulating materials, Super "Q" Radiant Barrier, for home, industry and mobile applications. The insulation combines industrial aluminum foil overlaid around a core of another material, usually propylene or mylar. The outer layer reflects up to 97 percent of heat; the central layer creates a thermal break in the structure and thus allows low radiant energy emission. The Quantum Cool Wall, used in cars and trucks, takes up little space while providing superior insulation, thus reducing spoilage and costs. The panels can also dampen sound and engine, exhaust and solar heat.

  4. Radiative opacities

    NASA Astrophysics Data System (ADS)

    Seaton, M. J.

    1993-01-01

    An overview of opacity calculations performed during the past decade is presented. Attention is given to envelopes and interiors, equations of state, atomic data, line profiles, and mesh points. Results for a Cepheid model are presented. The solar radiative interior, solar abundances, hydrogen and helium, and contributions from the different elements are discussed. Work over the past decade has led to major revisions in envelope opacities, by factors as large as 3 or 4. There are also some revisions in results for deeper layers, which are important but not so pronounced. A comparison of the work of two opacity research groups, OPAL from the Lawrence Livermore National Laboratory and the international OP project, is given.

  5. Radiation dosimeters

    DOEpatents

    Hoelsher, James W.; Hegland, Joel E.; Braunlich, Peter F.; Tetzlaff, Wolfgang

    1992-01-01

    Radiation dosimeters and dosimeter badges. The dosimeter badges include first and second parts which are connected to join using a securement to produce a sealed area in which at least one dosimeter is held and protected. The badge parts are separated to expose the dosimeters to a stimulating laser beam used to read dose exposure information therefrom. The badge is constructed to allow automated disassembly and reassembly in a uniquely fitting relationship. An electronic memory is included to provide calibration and identification information used during reading of the dosimeter. Dosimeter mounts which reduce thermal heating requirements are shown. Dosimeter constructions and production methods using thin substrates and phosphor binder-layers applied thereto are also taught.

  6. Radiation exposure of aircrews.

    PubMed

    Friedberg, Wallace; Copeland, Kyle; Duke, Frances E; Nicholas, Joyce S; Darden, Edgar B; O'Brien, Keran

    2002-01-01

    Information is provided about the radiation to which aircrews are exposed and possible health consequences. Recommended radiation exposure limits are given. Crewmembers on commercial aircraft are exposed to higher doses of ionizing radiation than normally received by members of the general population in most parts of the world. The principal ionizing radiation is galactic cosmic radiation. On infrequent occasions, radiation from the sun leads to an increase in the ionizing radiation at aircraft flight altitudes. Radioactive cargo is another possible source of exposure to ionizing radiation. Crewmembers are exposed to nonionizing radiation in the form of electric and magnetic fields generated by the aircraft s electronic and electrical systems. Other potential sources of nonionizing radiation exposure are microwave radiation from the aircraft's weather radar, laser radiation, and ultraviolet radiation.

  7. Negative hydrogen ion production mechanisms

    SciTech Connect

    Bacal, M.; Wada, M.

    2015-06-15

    Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

  8. Negative hydrogen ion production mechanisms

    NASA Astrophysics Data System (ADS)

    Bacal, M.; Wada, M.

    2015-06-01

    Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

  9. Adaptors for radiation detectors

    DOEpatents

    Livesay, Ronald Jason

    2015-07-28

    Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

  10. Adaptors for radiation detectors

    DOEpatents

    Livesay, Ronald Jason

    2014-04-22

    Described herein are adaptors and other devices for radiation detectors that can be used to make accurate spectral measurements of both small and large bulk sources of radioactivity, such as building structures, soils, vessels, large equipment, and liquid bodies. Some exemplary devices comprise an adaptor for a radiation detector, wherein the adaptor can be configured to collimate radiation passing through the adapter from an external radiation source to the radiation detector and the adaptor can be configured to enclose a radiation source within the adapter to allow the radiation detector to measure radiation emitted from the enclosed radiation source.

  11. 24. Duplicate negative of an historic negative. 'AERIAL VIEW OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. Duplicate negative of an historic negative. 'AERIAL VIEW OF AREA 'B' HOLSTON ORDNANCE WORKS.' 1944. #OCMH 4-12.2ASAV3 in Super Explosives Program RDX and Its Composition A, B, & C, Record Group No. 319, National Archives, Washington, D.C. - Holston Army Ammunition Plant, RDX-and-Composition-B Manufacturing Line 9, Kingsport, Sullivan County, TN

  12. A Negative Result About Some Concepts of Negative Dependence.

    DTIC Science & Technology

    1985-07-01

    It seems that either a very strong negative dependence holds with the monotonicity condition while without it, even a somewhat weak condition does...not hold. This brings out the crucial role played by the PF2 (log concave density) property in conditional negative dependence .

  13. On Negation as Mitigation: The Case of Negative Irony

    ERIC Educational Resources Information Center

    Giora, Rachel; Fein, Ofer; Ganzi, Jonathan; Levi, Natalie Alkeslassy; Sabah, Hadas

    2005-01-01

    Four experiments support the view of negation as mitigation (Giora, Balaban, Fein, & Alkabets, 2004). They show that when irony involves some sizable gap between what is said and what is criticized (He is exceptionally bright said of an idiot), it is rated as highly ironic (Giora, 1995). A negated version of that overstatement (He is not…

  14. Three chamber negative ion source

    DOEpatents

    Leung, K.N.; Ehlers, K.W.; Hiskes, J.R.

    1983-11-10

    It is an object of this invention provide a negative ion source which efficiently provides a large flux of negatively ionized particles. This invention provides a volume source of negative ions which has a current density sufficient for magnetic fusion applications and has electrons suppressed from the output. It is still another object of this invention to provide a volume source of negative ions which can be electrostatically accelerated to high energies and subsequently neutralized to form a high energy neutral beam for use with a magnetically confined plasma.

  15. Neurobiological background of negative symptoms.

    PubMed

    Galderisi, Silvana; Merlotti, Eleonora; Mucci, Armida

    2015-10-01

    Studies investigating neurobiological bases of negative symptoms of schizophrenia failed to provide consistent findings, possibly due to the heterogeneity of this psychopathological construct. We tried to review the findings published to date investigating neurobiological abnormalities after reducing the heterogeneity of the negative symptoms construct. The literature in electronic databases as well as citations and major articles are reviewed with respect to the phenomenology, pathology, genetics and neurobiology of schizophrenia. We searched PubMed with the keywords "negative symptoms," "deficit schizophrenia," "persistent negative symptoms," "neurotransmissions," "neuroimaging" and "genetic." Additional articles were identified by manually checking the reference lists of the relevant publications. Publications in English were considered, and unpublished studies, conference abstracts and poster presentations were not included. Structural and functional imaging studies addressed the issue of neurobiological background of negative symptoms from several perspectives (considering them as a unitary construct, focusing on primary and/or persistent negative symptoms and, more recently, clustering them into factors), but produced discrepant findings. The examined studies provided evidence suggesting that even primary and persistent negative symptoms include different psychopathological constructs, probably reflecting the dysfunction of different neurobiological substrates. Furthermore, they suggest that complex alterations in multiple neurotransmitter systems and genetic variants might influence the expression of negative symptoms in schizophrenia. On the whole, the reviewed findings, representing the distillation of a large body of disparate data, suggest that further deconstruction of negative symptomatology into more elementary components is needed to gain insight into underlying neurobiological mechanisms.

  16. Negative ions of polyatomic molecules.

    PubMed

    Christophorou, L G

    1980-06-01

    In this paper general concepts relating to, and recent advances in, the study of negative ions of polyatomic molecules area discussed with emphasis on halocarbons. The topics dealt with in the paper are as follows: basic electron attachment processes, modes of electron capture by molecules, short-lived transient negative ions, dissociative electron attachment to ground-state molecules and to "hot" molecules (effects of temperature on electron attachment), parent negative ions, effect of density, nature, and state of the medium on electron attachment, electron attachment to electronically excited molecules, the binding of attached electrons to molecules ("electron affinity"), and the basic and the applied significance of negative-ion studies.

  17. Causality, Nonlocality, and Negative Refraction.

    PubMed

    Forcella, Davide; Prada, Claire; Carminati, Rémi

    2017-03-31

    The importance of spatial nonlocality in the description of negative refraction in electromagnetic materials has been put forward recently. We develop a theory of negative refraction in homogeneous and isotropic media, based on first principles, and that includes nonlocality in its full generality. The theory shows that both dissipation and spatial nonlocality are necessary conditions for the existence of negative refraction. It also provides a sufficient condition in materials with weak spatial nonlocality. These fundamental results should have broad implications in the theoretical and practical analyses of negative refraction of electromagnetic and other kinds of waves.

  18. Brain representations of negative numbers.

    PubMed

    Parnes, Michael; Berger, Andrea; Tzelgov, Joseph

    2012-12-01

    Participants performed a physical comparison task of pairs of positive and pairs of negative one-digit numbers while their electrophysiological brain activity was measured. The numerical value of the presented digits was either congruent or incongruent with the physical size of the digits. Analysis has shown that the earliest event-related potential (ERP) difference between positive and negative numbers was found in the P300 ERP component peak, where there was an inverse effect of congruity in the negative pairs, compared with the positive ones. This pattern of results supports the idea that natural numbers serve as primitives of the human cognitive system, whereas negative numbers are apparently generated if needed.

  19. Neuroimaging correlates of negative priming.

    PubMed

    Steel, C; Haworth, E J; Peters, E; Hemsley, D R; Sharma, T; Gray, J A; Pickering, A; Gregory, L; Simmons, A; Bullmore, E T; Williams, S C

    2001-11-16

    Many theoretical accounts of selective attention and memory retrieval include reference to active inhibitory processes, such as those argued to underlie the negative priming effect. fMRI was used in order to investigate the areas of cortical activation associated with Stroop interference, Stroop facilitation and Stroop negative priming tasks. The most significant activation within the negative priming task was within the inferior parietal lobule, left temporal lobe and frontal lobes. Areas of cortical activation are discussed with reference to theoretical accounts of the negative priming effect.

  20. Negative terahertz conductivity in remotely doped graphene bilayer heterostructures

    SciTech Connect

    Ryzhii, V.; Ryzhii, M.; Mitin, V.; Shur, M. S.; Otsuji, T.

    2015-11-14

    Injection or optical generation of electrons and holes in graphene bilayers (GBLs) can result in the interband population inversion enabling the terahertz (THz) radiation lasing. The intraband radiative processes compete with the interband transitions. We demonstrate that remote doping enhances the indirect interband generation of photons in the proposed GBL heterostructures. Therefore, such remote doping helps to surpass the intraband (Drude) absorption, and results in large absolute values of the negative dynamic THz conductivity in a wide range of frequencies at elevated (including room) temperatures. The remotely doped GBL heterostructure THz lasers are expected to achieve higher THz gain compared with previously proposed GBL-based THz lasers.

  1. Radiation Therapy for Cancer

    Cancer.gov

    Radiation therapy is a type of cancer treatment that uses high doses of radiation to kill cancer cells and shrink tumors. Learn about the types of radiation, why side effects happen, which ones you might have, and more.

  2. Breast radiation - discharge

    MedlinePlus

    Radiation - breast - discharge ... away around 4 to 6 weeks after the radiation treatment is over. You may notice changes in ... breast looks or feels (if you are getting radiation after a lumpectomy). These changes include: Soreness or ...

  3. RADIATION SOURCE

    DOEpatents

    Gow, J.D.

    1961-06-27

    An improved version of a crossed electric and magnetic field plasma producing and containing device of the general character disclosed in U. S. Patent No. 2,967,943 is described. This device employs an annular magnet encased within an anode and a pair of cathodes respectively coaxially spaced from the opposite ends of the anode to establish crossed field electron trapping regions adjacent the ends of the anode. The trapping regions are communicably connected through the throat of the anode and the electric field negatively increases in opposite axial directions from the center of the throat. Electrons are trapped within the two trapping regions and throat to serve as a source of intense ionization to gas introduced thereto, the ions in copious quantities being attracted to the cathodes to bombard neutron productive targets dlsposed - thereat.

  4. Negation in the Chaamling Language.

    ERIC Educational Resources Information Center

    Rai, Vishnu S.

    This paper examines the different ways of forming negative sentences in the Chaamling language, an indigenous language spoken in the eastern, hilly districts of Nepal. It explains that negation, or negativization, in the Chaamling language is done with the help of affixation. In imperative sentences, the prefix mi- is added to the verb, which is…

  5. Be Aware of Negative Reinforcement.

    ERIC Educational Resources Information Center

    Cipani, Ennio C.

    1995-01-01

    This article examines the concept of negative reinforcement in relation to the maintenance of off-task and disruptive behaviors in classrooms. Suggestions are given for determining whether negative reinforcement (in the form of escape from the instructional task) or teacher attention is maintaining the behavior. Suggestions for making tasks less…

  6. Foam radiators for transition radiation detectors

    NASA Astrophysics Data System (ADS)

    Chernyatin, V.; Dolgoshein, B.; Gavrilenko, I.; Potekhin, M.; Romaniouk, A.; Sosnovtsev, V.

    1993-02-01

    A wide variety of foam radiators, potentially useful in the design of a transition radiation detector, the possible particle identification tool in collider experiments, have been tested in the beam. Various characteristics of these radiators are compared, and the conclusion is reached that certain brands of polyethylene foam are best suited for use in the detector. Comparison is made with a "traditional" radiator, which is a periodic structure of plastic foils.

  7. Physics of negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Abraham, Eitan; Penrose, Oliver

    2017-01-01

    Negative absolute temperatures were introduced into experimental physics by Purcell and Pound, who successfully applied this concept to nuclear spins; nevertheless, the concept has proved controversial: a recent article aroused considerable interest by its claim, based on a classical entropy formula (the "volume entropy") due to Gibbs, that negative temperatures violated basic principles of statistical thermodynamics. Here we give a thermodynamic analysis that confirms the negative-temperature interpretation of the Purcell-Pound experiments. We also examine the principal arguments that have been advanced against the negative temperature concept; we find that these arguments are not logically compelling, and moreover that the underlying "volume" entropy formula leads to predictions inconsistent with existing experimental results on nuclear spins. We conclude that, despite the counterarguments, negative absolute temperatures make good theoretical sense and did occur in the experiments designed to produce them.

  8. Solar radiation resource assessment

    SciTech Connect

    Not Available

    1990-11-01

    The bulletin discusses the following: introduction; Why is solar radiation resource assessment important Understanding the basics; the solar radiation resource assessment project; and future activities.

  9. Effect of Precipitable Water Vapor Amount on Radiative Cooling Performance

    NASA Astrophysics Data System (ADS)

    Hu, Mingke; Zhao, Bin; Ao, Xianze; Pei, Gang

    2017-05-01

    A radiative cooler based on aluminum-evaporated polyvinyl-fluoride surface was employed to investigate the effect of precipitable water vapor amount on its radiative cooling performance. A mathematic model of steady heat transfer that considers the spectral radiant distribution of the sky, the transparent cover and the collecting surface was established. The results indicate that the amount of precipitable water vapor shows a remarkable and negative effect on radiative cooling performance of the radiative cooler. Both the temperature difference between the cooler and surroundings and the net radiative cooling power decrease as the precipitable water vapor amount increases. The net radiative cooling power drops by about 41.0% as the the precipitable water vapor amount changes from 1.0 cm to 7.0 cm. Besides, the radiative cooler shows better cooling performance in winter than in summer. The net radiative cooling power in summer of Hefei is about 82.2% of that in winter.

  10. Hawking radiation via gravitational anomalies in nonspherical topologies

    SciTech Connect

    Papantonopoulos, Eleftherios; Skamagoulis, Petros

    2009-04-15

    We study the method of calculating Hawking radiation via gravitational anomalies in gravitational backgrounds of constant negative curvature. We apply the method to topological black holes and also to topological black holes conformally coupled to a scalar field.

  11. Three chamber negative ion source

    DOEpatents

    Leung, Ka-Ngo; Ehlers, Kenneth W.; Hiskes, John R.

    1985-01-01

    A negative ion vessel is divided into an excitation chamber, a negative ionization chamber and an extraction chamber by two magnetic filters. Input means introduces neutral molecules into a first chamber where a first electron discharge means vibrationally excites the molecules which migrate to a second chamber. In the second chamber a second electron discharge means ionizes the molecules, producing negative ions which are extracted into or by a third chamber. A first magnetic filter prevents high energy electrons from entering the negative ionization chamber from the excitation chamber. A second magnetic filter prevents high energy electrons from entering the extraction chamber from the negative ionizing chamber. An extraction grid at the end of the negative ion vessel attracts negative ions into the third chamber and accelerates them. Another grid, located adjacent to the extraction grid, carries a small positive voltage in order to inhibit positive ions from migrating into the extraction chamber and contour the plasma potential. Additional electrons can be suppressed from the output flux using ExB forces provided by magnetic field means and the extractor grid electric potential.

  12. Isotropic Negative Thermal Expansion Metamaterials.

    PubMed

    Wu, Lingling; Li, Bo; Zhou, Ji

    2016-07-13

    Negative thermal expansion materials are important and desirable in science and engineering applications. However, natural materials with isotropic negative thermal expansion are rare and usually unsatisfied in performance. Here, we propose a novel method to achieve two- and three-dimensional negative thermal expansion metamaterials via antichiral structures. The two-dimensional metamaterial is constructed with unit cells that combine bimaterial strips and antichiral structures, while the three-dimensional metamaterial is fabricated by a multimaterial 3D printing process. Both experimental and simulation results display isotropic negative thermal expansion property of the samples. The effective coefficient of negative thermal expansion of the proposed models is demonstrated to be dependent on the difference between the thermal expansion coefficient of the component materials, as well as on the circular node radius and the ligament length in the antichiral structures. The measured value of the linear negative thermal expansion coefficient of the three-dimensional sample is among the largest achieved in experiments to date. Our findings provide an easy and practical approach to obtaining materials with tunable negative thermal expansion on any scale.

  13. Multilayer structures as negative refractive and left-handed materials.

    PubMed

    Chui, S T; Chan, C T; Lin, Z F

    2006-02-15

    We examine multilayer structures as negative refractive index and left-handed materials, and find that for one polarization there is a wide range (≈90°) of incident angle within which negative refraction will occur. This comes about because the group velocity and the Poynting vector have a large component parallel to the layers, no matter what the angle of incidence of the incoming radiation is. This behaviour in turn comes from the large anisotropy of the phase velocities. If one of the components is a ferromagnetic metal, the system can be a left-handed material above the ferromagnetic resonance frequency.

  14. Overlapping illusions by transformation optics without any negative refraction material

    PubMed Central

    Sun, Fei; He, Sailing

    2016-01-01

    A novel method to achieve an overlapping illusion without any negative refraction index material is introduced with the help of the optic-null medium (ONM) designed by an extremely stretching spatial transformation. Unlike the previous methods to achieve such an optical illusion by transformation optics (TO), our method can achieve a power combination and reshape the radiation pattern at the same time. Unlike the overlapping illusion with some negative refraction index material, our method is not sensitive to the loss of the materials. Other advantages over existing methods are discussed. Numerical simulations are given to verify the performance of the proposed devices. PMID:26751285

  15. Overlapping illusions by transformation optics without any negative refraction material

    NASA Astrophysics Data System (ADS)

    Sun, Fei; He, Sailing

    2016-01-01

    A novel method to achieve an overlapping illusion without any negative refraction index material is introduced with the help of the optic-null medium (ONM) designed by an extremely stretching spatial transformation. Unlike the previous methods to achieve such an optical illusion by transformation optics (TO), our method can achieve a power combination and reshape the radiation pattern at the same time. Unlike the overlapping illusion with some negative refraction index material, our method is not sensitive to the loss of the materials. Other advantages over existing methods are discussed. Numerical simulations are given to verify the performance of the proposed devices.

  16. Negative ion chemistry in Titan's upper atmosphere

    NASA Astrophysics Data System (ADS)

    Vuitton, V.; Lavvas, P.; Yelle, R. V.; Wellbrock, A.; Lewis, G. R.; Coates, A.; Thissen, R.; Dutuit, O.

    2008-09-01

    In the upper part of atmospheres lies the ionosphere, a region of particular interest for planetary science, because it provides the link between the neutral atmosphere, and the ionizing processes from outer space. On Titan, it is created by the interaction of solar ultraviolet radiation and magnetospheric electrons with the main atmospheric constituents, N2 and CH4. Cassini has revealed that an extremely complex chemistry occurs in Titan's ionosphere. The INMS mass spectrometer detected positively charged hydrocarbons and nitrogen-bearing species with a charge-to-mass ratio (m/z) up to 100 amu [1]. In 2007, the Electron Spectrometer (ELS), one of the sensors making up the Cassini Plasma Spectrometer (CAPS) revealed the existence of numerous negative ions in Titan's upper atmosphere [2]. The data showed evidence for negatively charged ions with m/z up to 10,000 amu and at lower m/z for two distinct peaks below 50 amu, corresponding to a total density of ~200 cm-3, giving an anion to cation ratio of ~0.1. This detection happened almost simultaneously with the surprising discovery of four negative ions in the interstellar medium: C4H-, C6H-, C8H- and C3N- [3; 4; 5; 6; 7]. The possible presence of negative ions in Titan's upper atmosphere had only been briefly discussed before the Cassini-Huygens mission. Three-body electron attachment to radicals or collisional charging of aerosols had been suggested as a source of negatively charged species. Because the first process is negligible at high altitude (neutral densities lower than 1015 cm-3) and because aerosols were not expected above ~500 km, ionospheric models considered the presence of negatively charged species to be highly unlikely. However, the observations clearly show that Titan has the most complex ionosphere of the Solar System with an intense chemistry, leading to an increase of molecular size. By analyzing the optical properties of the detached haze layer observed at 520 km in Titan's mesosphere, Lavvas et

  17. Radiation Brain Drain? The Impact of Demographic Change on U.S. Radiation Protection.

    PubMed

    Hricak, Hedvig; Dauer, Lawrence T

    2017-02-01

    The use of radiation has a substantial beneficial impact, particularly in the areas of medicine, energy production, basic science research, and industrial applications. Radiation protection knowledge and experience are required for acquiring and implementing scientific knowledge to protect workers, members of the public, and the environment from potential harmful effects of ionizing radiation while facilitating the beneficial use and development of radiation-based technologies. However, demographic changes are negatively impacting U.S. radiation protection and response capabilities. The number of radiation professionals continues to decrease even as the demand for such professionals is growing. These concerns are most pronounced in the medical, energy, research, and security arenas. Though the United States has been the world leader in radiation protection and radiation sciences for many years, the country has no strategic plan to ensure the maintenance of expertise in radiobiology, radiation physics, and radiation protection. Solving this problem will require a significant increase in federal and state funding as well as formal partnerships and initiatives among academia, professional societies, government, and the private sector.

  18. Tunable acoustic double negativity metamaterial.

    PubMed

    Liang, Z; Willatzen, M; Li, J; Christensen, J

    2012-01-01

    Man-made composite materials called "metamaterials" allow for the creation of unusual wave propagation behavior. Acoustic and elastic metamaterials in particular, can pave the way for the full control of sound in realizing cloaks of invisibility, perfect lenses and much more. In this work we design acousto-elastic surface modes that are similar to surface plasmons in metals and on highly conducting surfaces perforated by holes. We combine a structure hosting these modes together with a gap material supporting negative modulus and collectively producing negative dispersion. By analytical techniques and full-wave simulations we attribute the observed behavior to the mass density and bulk modulus being simultaneously negative.

  19. Cognitive representation of negative numbers.

    PubMed

    Fischer, Martin H

    2003-05-01

    To understand negative numbers, must we refer to positive number representations (the phylogenetic hypothesis), or do we acquire a negative mental number line (the ontogenetic hypothesis)? In the experiment reported here, participants made lateralized button responses to indicate the larger of two digits from the range -9 to 9. Digit pairs were displayed spatially congruent or incongruent with either a phylogenetic or an ontogenetic mental number line. The pattern of decision latencies suggests that negative numbers become associated with left space, thus supporting the ontogenetic view.

  20. Radiation exposure at ground level by secondary cosmic radiation.

    PubMed

    Wissmann, F; Dangendorf, V; Schrewe, U

    2005-01-01

    The contribution of the charged component of secondary cosmic radiation to the ambient dose equivalent H*(10) at ground level is investigated using the muon detector MUDOS and a TEPC detector surrounded by the coincidence detector CACS to identify charged particles. The ambient dose equivalent rate H*(10)T as measured with the TEPC/CACS is used to calibrate the MUDOS count rate in terms of H*(10). First results from long-term measurements at the PTB reference site for ambient radiation dosimetry are reported. The air pressure corrected dose rate shows, as expected, a strong correlation with the neutron count rate as measured with the Kiel neutron monitor. The measured seasonal variations exhibit a negative correlation with the temperature changes in the upper layers of the atmosphere where the ground level muons are produced.

  1. Piezoelectric enhancement under negative pressure

    PubMed Central

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-01-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones. PMID:27396411

  2. Negative Refraction in Weyl Semimetals

    NASA Astrophysics Data System (ADS)

    Shoufie Ukhtary, Muhammad; Nugraha, Ahmad R. T.; Saito, Riichiro

    2017-10-01

    We theoretically propose that Weyl semimetals may exhibit negative refraction at some frequencies close to the plasmon frequency, allowing transverse magnetic (TM) electromagnetic waves with frequencies smaller than the plasmon frequency to propagate in the Weyl semimetals. The idea is justified by the calculation of reflection spectra, in which negative refractive index at such frequencies gives physically correct spectra. In this case, a TM electromagnetic wave incident to the surface of the Weyl semimetal will be bent with a negative angle of refraction. We argue that the negative refractive index at the specified frequencies of the electromagnetic wave is required to conserve the energy of the wave, in which the incident energy should propagate away from the point of incidence.

  3. Adjective Metaphors Evoke Negative Meanings

    PubMed Central

    Sakamoto, Maki; Utsumi, Akira

    2014-01-01

    Previous metaphor studies have paid much attention to nominal metaphors and predicative metaphors, but little attention has been given to adjective metaphors. Although some studies have focused on adjective metaphors, they only examined differences in the acceptability of various types of adjective metaphors. This paper explores the cognitive effects evoked by adjective metaphors. Three psychological experiments revealed that (1) adjective metaphors, especially those modified by color adjectives, tend to evoke negative effect; (2) although the meanings of metaphors are basically affected by the meanings of their vehicles, when a vehicle has a neutral meaning, negative meanings are evoked most frequently for adjective metaphors compared to nominal and predicative metaphors; (3) negative meanings evoked by adjective metaphors are related to poeticness, and poetic metaphors evoke negative meanings more easily than less poetic metaphors. Our research sheds new light on studies of the use of metaphor, which is one of the most basic human cognitive abilities. PMID:24586480

  4. Negative numbers in simple arithmetic.

    PubMed

    Das, Runa; LeFevre, Jo-Anne; Penner-Wilger, Marcie

    2010-10-01

    Are negative numbers processed differently from positive numbers in arithmetic problems? In two experiments, adults (N = 66) solved standard addition and subtraction problems such as 3 + 4 and 7 - 4 and recasted versions that included explicit negative signs-that is, 3 - (-4), 7 + (-4), and (-4) + 7. Solution times on the recasted problems were slower than those on standard problems, but the effect was much larger for addition than subtraction. The negative sign may prime subtraction in both kinds of recasted problem. Problem size effects were the same or smaller in recasted than in standard problems, suggesting that the recasted formats did not interfere with mental calculation. These results suggest that the underlying conceptual structure of the problem (i.e., addition vs. subtraction) is more important for solution processes than the presence of negative numbers.

  5. Piezoelectric enhancement under negative pressure

    NASA Astrophysics Data System (ADS)

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-07-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones.

  6. Piezoelectric enhancement under negative pressure.

    PubMed

    Kvasov, Alexander; McGilly, Leo J; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S; Sluka, Tomas; Tagantsev, Alexander K; Setter, Nava

    2016-07-11

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones.

  7. Two ultraviolet radiation datasets that cover China

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Hu, Bo; Wang, Yuesi; Liu, Guangren; Tang, Liqin; Ji, Dongsheng; Bai, Yongfei; Bao, Weikai; Chen, Xin; Chen, Yunming; Ding, Weixin; Han, Xiaozeng; He, Fei; Huang, Hui; Huang, Zhenying; Li, Xinrong; Li, Yan; Liu, Wenzhao; Lin, Luxiang; Ouyang, Zhu; Qin, Boqiang; Shen, Weijun; Shen, Yanjun; Su, Hongxin; Song, Changchun; Sun, Bo; Sun, Song; Wang, Anzhi; Wang, Genxu; Wang, Huimin; Wang, Silong; Wang, Youshao; Wei, Wenxue; Xie, Ping; Xie, Zongqiang; Yan, Xiaoyuan; Zeng, Fanjiang; Zhang, Fawei; Zhang, Yangjian; Zhang, Yiping; Zhao, Chengyi; Zhao, Wenzhi; Zhao, Xueyong; Zhou, Guoyi; Zhu, Bo

    2017-07-01

    Ultraviolet (UV) radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization's measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes.

  8. Antinuclear Antibody Negative Systemic Sclerosis

    PubMed Central

    Salazar, GA; Assassi, S; Wigley, F; Hummers, L; Varga, J; Hinchcliff, M; Khanna, D; Schiopu, E; Phillips, K; Furst, DE; Steen, V; Baron, M; Hudson, M; Taillefer, SS; Pope, J; Jones, N; Docherty, P; Khalidi, NA; Robinson, D; Simms, R; Silver, R; Frech, TM; Fessler, B; Molitor, J; Fritzler, M; Segal, B; Al-Kassab, F; Perry, M; Yang, J; Zamanian, S; Reveille, JD; Arnett, FC; Pedroza, C; Mayes, MD

    2014-01-01

    Objective To examine the demographic and clinical characteristics of systemic sclerosis (SSc) patients without antinuclear antibodies (ANA) compared to ANA positive patients. Methods SSc patients enrolled in the Scleroderma Family Registry and DNA Repository were included. Relevant demographic and clinical data were entered by participating sites or obtained by chart review. ANA and SSc related antibodies were determined in all investigated patients using commercially available kits at our laboratories. Results This study included 3249 patients, of whom 208 (6.4%) were ANA negative. The proportion of male patients was higher in the ANA negative group (OR 1.65; p=0.008). ANA negative patients experienced less vasculopathic manifestations of SSc. The percent predicted diffusing capacity of carbon monoxide (DLco) was higher in ANA negative patients (p=0.03). Pulmonary arterial hypertension (PAH) per right heart catheterization was less common in the ANA negative group (OR= 0.28; p=0.03). Furthermore, patients with negative ANA had a lower prevalence of telangiectasias and digital ulcers/pits (OR= 0.59; p=0.03 and OR=0.38; p=0.01, respectively). Although diffuse cutaneous involvement was more common, the modified Rodnan Skin Score (mRSS) was lower in the ANA negative group (2.4 points lower, p=0.05). Furthermore, they experienced more malabsorption (p=0.05). There was no difference in the frequency of pulmonary fibrosis or scleroderma renal crisis. All-cause mortality was not different between the two groups (p=0.28). Conclusions In conclusion, the results of this study suggest that SSc patients who are ANA negative constitute a distinct subset of SSc with less vasculopathy (less PAH, digital ulcers and fewer telangiectasias), a greater proportion of males and possibly, more frequent lower gastrointestinal involvement. PMID:25578738

  9. Microwave radio emissions of negative cloud-to-ground lightning flashes

    NASA Astrophysics Data System (ADS)

    Petersen, D.; Beasley, W.

    2014-01-01

    We report preliminary results of a new observational study of microwave-frequency electromagnetic radiation that is emitted by lightning discharge processes. Radiation was observed with a ceramic patch antenna and a digital radio receiver tuned to a center frequency of 1.63 GHz and a bandwidth of 2 MHz. The recorded radiation waveforms are compared with data collected by the Oklahoma Lightning Mapping Array (OKLMA) lightning mapping system and the co-located Earth Networks Total Lightning Network (ENTLN) broadband electric field antenna. Microwave radiation was observed to occur during preliminary breakdown, negative stepped leader breakdown, negative dart leader breakdown, and return strokes. Characteristic radiation signatures were observed, including trains of individually resolvable impulses during breakdown and brief but intense trains of noise-like bursts during return strokes.

  10. [Negative symptoms and cerebral imaging].

    PubMed

    Kaladjian, A; Belzeaux, R; Adida, M; Azorin, J-M

    2015-12-01

    A number of neuroanatomical and neurofonctional abnormalities have been evidenced by cerebral imaging studies in patients suffering from schizophrenia. Nevertheless, those specifically associated with the negative symptoms of this disease are still insufficiently known. This work is a review of selected studies that have assessed the brain correlates of negative symptoms in schizophrenia. Approaches using structural imaging have highlighted reduction of gray matter density or cortical thickness associated with negative symptoms, which is rather sparsely distributed within the frontal and temporal regions, localized nevertheless more particularly in the frontal medial and orbitofrontal areas, as well as the amygdalo-hippocampic complex. These deficits are concurrent with a loss of integrity of the principal paths of white matter tracts between frontal and limbic regions. On the other hand, neurofonctional abnormalities associated with negative symptoms involve especially the frontal areas and limbic striatum. A disturbed functioning within the fronto-striatal loops, related to a striatal dopaminergic deficit, may represent a potential explanatory hypothesis of the negative symptoms of schizophrenia, as suggested by studies using Positron Emission Tomography on this topic or neuroimaging studies on the effects of antipsychotics. A better identification of the cerebral abnormalities associated with the negative dimension of schizophrenia, with regard to the lateralization of these abnormalities or to their changes during the course of the disease, could offer new therapeutic modalities for the treatment of this dimension which, until now, remains few responsive to conventional pharmacological treatments. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  11. Radiation and People

    ERIC Educational Resources Information Center

    Freilich, Florence G.

    1970-01-01

    Describes the development of radiation as a tool of medicine. Includes topics on history of radiation, electromagnetic spectrum, X-ray tubes, high energy machines, radioactive sources, artificial radioactivity, radioactive scanning, units, present radiation background, and effect of radiation on living tissue. (DS)

  12. Radiation and People

    ERIC Educational Resources Information Center

    Freilich, Florence G.

    1970-01-01

    Describes the development of radiation as a tool of medicine. Includes topics on history of radiation, electromagnetic spectrum, X-ray tubes, high energy machines, radioactive sources, artificial radioactivity, radioactive scanning, units, present radiation background, and effect of radiation on living tissue. (DS)

  13. Radiation transport calculations for cosmic radiation.

    PubMed

    Endo, A; Sato, T

    2012-01-01

    The radiation environment inside and near spacecraft consists of various components of primary radiation in space and secondary radiation produced by the interaction of the primary radiation with the walls and equipment of the spacecraft. Radiation fields inside astronauts are different from those outside them, because of the body's self-shielding as well as the nuclear fragmentation reactions occurring in the human body. Several computer codes have been developed to simulate the physical processes of the coupled transport of protons, high-charge and high-energy nuclei, and the secondary radiation produced in atomic and nuclear collision processes in matter. These computer codes have been used in various space radiation protection applications: shielding design for spacecraft and planetary habitats, simulation of instrument and detector responses, analysis of absorbed doses and quality factors in organs and tissues, and study of biological effects. This paper focuses on the methods and computer codes used for radiation transport calculations on cosmic radiation, and their application to the analysis of radiation fields inside spacecraft, evaluation of organ doses in the human body, and calculation of dose conversion coefficients using the reference phantoms defined in ICRP Publication 110. Copyright © 2012. Published by Elsevier Ltd.

  14. Thermal radiation heat transfer.

    NASA Technical Reports Server (NTRS)

    Siegel, R.; Howell, J. R.

    1972-01-01

    A comprehensive discussion of heat transfer by thermal radiation is presented, including the radiative behavior of materials, radiation between surfaces, and gas radiation. Among the topics considered are property prediction by electromagnetic theory, the observed properties of solid materials, radiation in the presence of other modes of energy transfer, the equations of transfer for an absorbing-emitting gas, and radiative transfer in scattering and absorbing media. Also considered are radiation exchange between black isothermal surfaces, radiation exchange in enclosures composed of diffuse gray surfaces and in enclosures having some specularly reflecting surfaces, and radiation exchange between nondiffuse nongray surfaces. The use of the Monte Carlo technique in solving radiant-exchange problems and problems of radiative transfer through absorbing-emitting media is explained.

  15. Radiation stability in optoelectronics

    NASA Astrophysics Data System (ADS)

    Zaitov, Farit Alimovich; Litvinova, Nadezhda Nikolaevna; Savitskii, Vladimir Grigor'evich; Sredin, Viktor Gennadievich

    The book deals with various aspects of the radiation stability of some commonly used semiconductor optoelectronic instruments, such as radiation sources and detectors, solar energy converters, and certain types of glasses and fibers. In particular, attention is given to the classification and principal physical characteristics of ionizing radiations, principal types of optoelectronic semiconductor instruments, effect of ionizing radiation on photosensitive and light-emitting semiconductor structures, and effect of ionizing radiation on semiconducting materials.

  16. Wireless radiation sensor

    DOEpatents

    Lamberti, Vincent E.; Howell, Jr, Layton N.; Mee, David K.; Kress, Reid L.

    2016-08-09

    Disclosed is a sensor for detecting radiation. The sensor includes a ferromagnetic metal and a radiation sensitive material coupled to the ferromagnetic metal. The radiation sensitive material is operable to change a tensile stress of the ferromagnetic metal upon exposure to radiation. The radiation is detected based on changes in the magnetic switching characteristics of the ferromagnetic metal caused by the changes in the tensile stress.

  17. Plasma neutralizers for H negative or D negative beams

    NASA Astrophysics Data System (ADS)

    Berkner, K. H.; Pyle, R. V.; Savas, S. E.; Stalder, K. R.

    1980-10-01

    Plasma neutralizers can produce higher conversion efficiencies than are obtainable with gas neutralizers for the production of high-energy neutral beams from negative hydrogen ions. Little attention has been paid to experimental neutralizer studies because of the more critical problems connected with the development of negative-ion sources. With the prospect of accelerating ampere dc beams from extrapolatable ion sources some time next year, plasma neutralizers are being re-examined. Some basic considerations, two introductory experiments, and a next-step experiment are described.

  18. Radiation image photographic apparatus

    SciTech Connect

    Kohno, H.; Sekihara, K.; Shiono, H.; Suzuki, T.; Yanaka, S.

    1984-11-27

    A radiation-image photographing apparatus comprises a radiation source, a radiation detector disposed in opposition to the radiation source for detecting radiation through an object to be examined and to generate an electrical signal proportional to the amount of incident radiation, a scanning device for changing the relative, positional relationship between the radiation source and the radiation detector, an analog-to-digital converter for converting the output signal from the radiation detector to a digital quantity, a memory for storing the digital signal, an arithmetic unit, and a display unit. A plurality of measurements of a two-dimensional radiation absorption distribution of the object disposed between the radiation source and the radiation detector is obtained while the relative positional relationship between the radiation source and the radiation detector is being changed, and a linear arithmetic operation is performed on the plurality of image measurements, or a set of data passing a point within the object to be photographed, thereby displaying a cross-sectional image on a given cross-section approximately parallel to the radiation detector plane within the object to be examined.

  19. Adaptive radiation versus 'radiation' and 'explosive diversification': why conceptual distinctions are fundamental to understanding evolution.

    PubMed

    Givnish, Thomas J

    2015-07-01

    Adaptive radiation is the rise of a diversity of ecological roles and role-specific adaptations within a lineage. Recently, some researchers have begun to use 'adaptive radiation' or 'radiation' as synonymous with 'explosive species diversification'. This essay aims to clarify distinctions between these concepts, and the related ideas of geographic speciation, sexual selection, key innovations, key landscapes and ecological keys. Several examples are given to demonstrate that adaptive radiation and explosive diversification are not the same phenomenon, and that focusing on explosive diversification and the analysis of phylogenetic topology ignores much of the rich biology associated with adaptive radiation, and risks generating confusion about the nature of the evolutionary forces driving species diversification. Some 'radiations' involve bursts of geographic speciation or sexual selection, rather than adaptive diversification; some adaptive radiations have little or no effect on speciation, or even a negative effect. Many classic examples of 'adaptive radiation' appear to involve effects driven partly by geographic speciation, species' dispersal abilities, and the nature of extrinsic dispersal barriers; partly by sexual selection; and partly by adaptive radiation in the classical sense, including the origin of traits and invasion of adaptive zones that result in decreased diversification rates but add to overall diversity. © 2015 The Author. New Phytologist © 2015 New Phytologist Trust.

  20. Radiation protection guidelines for radiation emergencies

    SciTech Connect

    Lessard, E.T.; Meinhold, C.B.

    1986-01-01

    The system of dose limitation and present guidance for emergency workers and guidance for intervention on behalf of the public are discussed. There are three elements for the system of dose limitation: justification, optimization and dose limits. The first element is basically a political process in this country. Justification is based on a risk-benefit analysis, and justification of the use of radioactive materials or radiation is generally not within the authority of radiation protection managers. Radiation protection managers typically assess detriments or harm caused by radiation exposure and have very little expertise in assessing the benefits of a particular practice involving nuclear material.

  1. Negative Items and Negation Strategies in Nonnative Italian.

    ERIC Educational Resources Information Center

    Bernini, Giuliano

    2000-01-01

    Acquisition of negation in Italian as a second language (L2) is investigated on the basis of the longitudinal data of five learners with different first languages in the framework of a functional approach focusing on the semantic and pragmatic principles governing the organization of learner varieties and the process of their complexification.…

  2. Solar ultraviolet radiation in a changing climate

    NASA Astrophysics Data System (ADS)

    Williamson, Craig E.; Zepp, Richard G.; Lucas, Robyn M.; Madronich, Sasha; Austin, Amy T.; Ballaré, Carlos L.; Norval, Mary; Sulzberger, Barbara; Bais, Alkiviadis F.; McKenzie, Richard L.; Robinson, Sharon A.; Häder, Donat-P.; Paul, Nigel D.; Bornman, Janet F.

    2014-06-01

    The projected large increases in damaging ultraviolet radiation as a result of global emissions of ozone-depleting substances have been forestalled by the success of the Montreal Protocol. New challenges are now arising in relation to climate change. We highlight the complex interactions between the drivers of climate change and those of stratospheric ozone depletion, and the positive and negative feedbacks among climate, ozone and ultraviolet radiation. These will result in both risks and benefits of exposure to ultraviolet radiation for the environment and human welfare. This Review synthesizes these new insights and their relevance in a world where changes in climate as well as in stratospheric ozone are altering exposure to ultraviolet radiation with largely unknown consequences for the biosphere.

  3. A global radiative-convective feedback

    NASA Technical Reports Server (NTRS)

    Fowler, Laura D.; Randall, David A.

    1994-01-01

    We have investigated the sensitivity of the intensity of convective activity and atmospheric radiative cooling to radiatively thick upper-tropospheric clouds using a new version of the Colorado State University General Circulation Model (CSU GCM). The model includes a bulk cloud microphysics scheme to predict the formation of cloud water, cloud ice, rain, and snow. The cloud optical properties are interactive and dependent upon the cloud water and cloud ice paths. We find that the formation of a persistent upper tropospheric cloud ice shield leads to decreased atmospheric radiative cooling and increased static stability. Convective activity is then strongly suppressed. In this way, upper-tropospheric clouds act as regulators of the global hydrologic cycle, and provide a negative feedback between atmospheric radiative cooling and convective activity.

  4. Pediatric Exposures to Ionizing Radiation: Carcinogenic Considerations

    PubMed Central

    Kutanzi, Kristy R.; Lumen, Annie; Koturbash, Igor; Miousse, Isabelle R.

    2016-01-01

    Children are at a greater risk than adults of developing cancer after being exposed to ionizing radiation. Because of their developing bodies and long life expectancy post-exposure, children require specific attention in the aftermath of nuclear accidents and when radiation is used for diagnosis or treatment purposes. In this review, we discuss the carcinogenic potential of pediatric exposures to ionizing radiation from accidental, diagnostic, and therapeutic modalities. Particular emphasis is given to leukemia and thyroid cancers as consequences of accidental exposures. We further discuss the evidence of cancers that arise as a result of radiotherapy and conclude the review with a summary on the available literature on the links between computer tomography (CT) and carcinogenesis. Appropriate actions taken to mitigate or minimize the negative health effects of pediatric exposures to ionizing radiation and future considerations are discussed. PMID:27801855

  5. Neurobiological toxicity of radiation in hippocampal cells.

    PubMed

    Kim, Joong-Sun; Yang, Miyoung; Kim, Sung-Ho; Shin, Taekyun; Moon, Changjong

    2013-03-01

    Worldwide radiation exposure is increasing due to recent nuclear accidents, space travel, atomic weapons testing and use, and medical treatments. In adult animals, ionizing radiation can significantly impact hippocampal neurogenesis and negatively affect hippocampal functions such as cognition. However, there is considerable uncertainty regarding the mechanisms underlying these effects. This article reviews in vivo and in vitro studies on the effects of irradiation on hippocampal neurogenesis and function in order to gain new mechanistic insights. This information will provide complementary views of our understanding of the normal brain's tolerance to radiation exposure, the potentially serious implications of radiation exposure to cognition, and lead to a discussion of potential strategies for pharmacotherapy and behavioral intervention.

  6. A global radiative-convective feedback

    NASA Technical Reports Server (NTRS)

    Fowler, Laura D.; Randall, David A.

    1994-01-01

    We have investigated the sensitivity of the intensity of convective activity and atmospheric radiative cooling to radiatively thick upper-tropospheric clouds using a new version of the Colorado State University General Circulation Model (CSU GCM). The model includes a bulk cloud microphysics scheme to predict the formation of cloud water, cloud ice, rain, and snow. The cloud optical properties are interactive and dependent upon the cloud water and cloud ice paths. We find that the formation of a persistent upper tropospheric cloud ice shield leads to decreased atmospheric radiative cooling and increased static stability. Convective activity is then strongly suppressed. In this way, upper-tropospheric clouds act as regulators of the global hydrologic cycle, and provide a negative feedback between atmospheric radiative cooling and convective activity.

  7. Tunable acoustic double negativity metamaterial

    PubMed Central

    Liang, Z.; Willatzen, M.; Li, J.; Christensen, J.

    2012-01-01

    Man-made composite materials called “metamaterials” allow for the creation of unusual wave propagation behavior. Acoustic and elastic metamaterials in particular, can pave the way for the full control of sound in realizing cloaks of invisibility, perfect lenses and much more. In this work we design acousto-elastic surface modes that are similar to surface plasmons in metals and on highly conducting surfaces perforated by holes. We combine a structure hosting these modes together with a gap material supporting negative modulus and collectively producing negative dispersion. By analytical techniques and full-wave simulations we attribute the observed behavior to the mass density and bulk modulus being simultaneously negative. PMID:23152948

  8. Negative-Pressure Pulmonary Edema.

    PubMed

    Bhattacharya, Mallar; Kallet, Richard H; Ware, Lorraine B; Matthay, Michael A

    2016-10-01

    Negative-pressure pulmonary edema (NPPE) or postobstructive pulmonary edema is a well-described cause of acute respiratory failure that occurs after intense inspiratory effort against an obstructed airway, usually from upper airway infection, tumor, or laryngospasm. Patients with NPPE generate very negative airway pressures, which augment transvascular fluid filtration and precipitate interstitial and alveolar edema. Pulmonary edema fluid collected from most patients with NPPE has a low protein concentration, suggesting hydrostatic forces as the primary mechanism for the pathogenesis of NPPE. Supportive care should be directed at relieving the upper airway obstruction by endotracheal intubation or cricothyroidotomy, institution of lung-protective positive-pressure ventilation, and diuresis unless the patient is in shock. Resolution of the pulmonary edema is usually rapid, in part because alveolar fluid clearance mechanisms are intact. In this review, we discuss the clinical presentation, pathophysiology, and management of negative-pressure or postobstructive pulmonary edema.

  9. Negativity Bias in Dangerous Drivers

    PubMed Central

    Chai, Jing; Qu, Weina; Sun, Xianghong; Zhang, Kan; Ge, Yan

    2016-01-01

    The behavioral and cognitive characteristics of dangerous drivers differ significantly from those of safe drivers. However, differences in emotional information processing have seldom been investigated. Previous studies have revealed that drivers with higher anger/anxiety trait scores are more likely to be involved in crashes and that individuals with higher anger traits exhibit stronger negativity biases when processing emotions compared with control groups. However, researchers have not explored the relationship between emotional information processing and driving behavior. In this study, we examined the emotional information processing differences between dangerous drivers and safe drivers. Thirty-eight non-professional drivers were divided into two groups according to the penalty points that they had accrued for traffic violations: 15 drivers with 6 or more points were included in the dangerous driver group, and 23 drivers with 3 or fewer points were included in the safe driver group. The emotional Stroop task was used to measure negativity biases, and both behavioral and electroencephalograph data were recorded. The behavioral results revealed stronger negativity biases in the dangerous drivers than in the safe drivers. The bias score was correlated with self-reported dangerous driving behavior. Drivers with strong negativity biases reported having been involved in mores crashes compared with the less-biased drivers. The event-related potentials (ERPs) revealed that the dangerous drivers exhibited reduced P3 components when responding to negative stimuli, suggesting decreased inhibitory control of information that is task-irrelevant but emotionally salient. The influence of negativity bias provides one possible explanation of the effects of individual differences on dangerous driving behavior and traffic crashes. PMID:26765225

  10. Sigma models with negative curvature

    NASA Astrophysics Data System (ADS)

    Alonso, Rodrigo; Jenkins, Elizabeth E.; Manohar, Aneesh V.

    2016-05-01

    We construct Higgs Effective Field Theory (HEFT) based on the scalar manifold Hn, which is a hyperbolic space of constant negative curvature. The Lagrangian has a non-compact O (n , 1) global symmetry group, but it gives a unitary theory as long as only a compact subgroup of the global symmetry is gauged. Whether the HEFT manifold has positive or negative curvature can be tested by measuring the S-parameter, and the cross sections for longitudinal gauge boson and Higgs boson scattering, since the curvature (including its sign) determines deviations from Standard Model values.

  11. Negative-viscosity lattice gases

    SciTech Connect

    Rothman, D.H. )

    1989-08-01

    A new irreversible collision rule is introduced for lattice-gas automata. The rule maximizes the flux of momentum in the direction of the local momentum gradient, yielding a negative shear viscosity. Numerically results in 2D show that the negative viscosity leads to the spontaneous ordering of the velocity field, with vorticity resolvable down to one lattice-link length. The new rule may be used in conjunction with previously proposed collision rules to yield a positive shear viscosity lower than the previous rules provide. In particular, Poiseuille flow tests demonstrate a decrease in viscosity by more than a factor of 2.

  12. Sigma models with negative curvature

    DOE PAGES

    Alonso, Rodrigo; Jenkins, Elizabeth E.; Manohar, Aneesh V.

    2016-03-16

    Here, we construct Higgs Effective Field Theory (HEFT) based on the scalar manifold Hn, which is a hyperbolic space of constant negative curvature. The Lagrangian has a non-compact O(n, 1) global symmetry group, but it gives a unitary theory as long as only a compact subgroup of the global symmetry is gauged. Whether the HEFT manifold has positive or negative curvature can be tested by measuring the S-parameter, and the cross sections for longitudinal gauge boson and Higgs boson scattering, since the curvature (including its sign) determines deviations from Standard Model values.

  13. Patch Test Negative Generalized Dermatitis.

    PubMed

    Spiker, Alison; Mowad, Christen

    2016-01-01

    Allergic contact dermatitis is a common condition in dermatology. Patch testing is the criterion standard for diagnosis. However, dermatitis is not always caused by an allergen, and patch testing does not identify a culprit in every patient. Generalized dermatitis, defined as eczematous dermatitis affecting greater than 3 body sites, is often encountered in dermatology practice, especially patch test referral centers. Management for patients with generalized dermatitis who are patch test negative is challenging. The purpose of this article is to outline an approach to this challenging scenario and summarize the paucity of existing literature on patch test negative generalized dermatitis.

  14. Plutonium radiation surrogate

    DOEpatents

    Frank, Michael I [Dublin, CA

    2010-02-02

    A self-contained source of gamma-ray and neutron radiation suitable for use as a radiation surrogate for weapons-grade plutonium is described. The source generates a radiation spectrum similar to that of weapons-grade plutonium at 5% energy resolution between 59 and 2614 keV, but contains no special nuclear material and emits little .alpha.-particle radiation. The weapons-grade plutonium radiation surrogate also emits neutrons having fluxes commensurate with the gamma-radiation intensities employed.

  15. Introduction to radiation transport

    SciTech Connect

    Olson, G.L.

    1998-12-31

    This lecture will present time-dependent radiation transport where the radiation is coupled to a static medium, i.e., the material is not in motion. In reality, radiation exerts a pressure on the materials it propagates through and will accelerate the material in the direction of the radiation flow. This fully coupled problem with radiation transport and materials in motion is referred to as radiation-hydrodynamics (or in a shorthand notation: rad-hydro) and is beyond the scope of this lecture.

  16. Some Concepts of Negative Dependence.

    DTIC Science & Technology

    1980-03-01

    The theory of positive dependence notions cannot yield useful results for some widely used distributions such as the multinomial, Dirichlet and the...multivariate hypergeometric. Some conditions of negative dependence that are satisfied by these distributions and which have practical meaning are

  17. Negative Geography: Locating Things Elsewhere.

    ERIC Educational Resources Information Center

    Stoddard, Robert H.

    The phenomenon of negative geography--the assertion that any location is better than the one selected--is discussed and ways in which this approach differs from traditional geography methodology are analyzed. Case studies of two citizens' groups which protested the relocation of a city mission and halfway house in their neighborhoods illustrate…

  18. Photonic crystal negative refractive optics.

    PubMed

    Baba, Toshihiko; Abe, Hiroshi; Asatsuma, Tomohiko; Matsumoto, Takashi

    2010-03-01

    Photonic crystals (PCs) are multi-dimensional periodic gratings, in which the light propagation is dominated by Bragg diffraction that appears to be refraction at the flat surfaces of the PC. The refraction angle from positive to negative, perfectly or only partially obeying Snell's law, can be tailored using photonic band theory. The negative refraction enables novel prism, collimation, and lens effects. Because PCs usually consist of two transparent media, these effects occur at absorption-free frequencies, affording significant design flexibility for free-space optics. The PC slab, a high-index membrane with a two-dimensional airhole array, must be carefully designed to avoid reflection and diffraction losses. Light focusing based on negative refraction forms a parallel image of a light source, facilitating optical couplers and condenser lenses for wavelength demultiplexing. A compact wavelength demultiplexer can be designed by combining the prism and lens effects. The collimation effect is obtainable not only inside but also outside of the PC by optimizing negative refractive condition.

  19. Questioning Zero and Negative Numbers

    ERIC Educational Resources Information Center

    Wilcox, Virginia B.

    2008-01-01

    After experiencing a Developing Mathematical Ideas (DMI) class on the construction of algebraic concepts surrounding zero and negative numbers, the author conducted an interview with a first grader to determine the youngster's existing level of understanding about these topics. Uncovering young students' existing understanding can provide focus…

  20. Unimode metamaterials exhibiting negative linear compressibility and negative thermal expansion

    NASA Astrophysics Data System (ADS)

    Dudek, Krzysztof K.; Attard, Daphne; Caruana-Gauci, Roberto; Wojciechowski, Krzysztof W.; Grima, Joseph N.

    2016-02-01

    Unimode metamaterials made from rotating rigid triangles are analysed mathematically for their mechanical and thermal expansion properties. It is shown that these unimode systems exhibit positive Poisson’s ratios irrespective of size, shape and angle of aperture, with the Poisson’s ratio exhibiting giant values for certain conformations. When the Poisson’s ratio in one loading direction is larger than +1, the systems were found to exhibit the anomalous property of negative linear compressibility along this direction, that is, the systems expand in this direction when hydrostatically compressed. Also discussed are the thermal expansion properties of these systems under the assumption that the units exhibit increased rotational agitation once subjected to an increase in temperature. The effect of the geometric parameters on the aforementioned thermo-mechanical properties of the system, are discussed, with the aim of identifying negative behaviour.

  1. Radiation protection at synchrotron radiation facilities.

    PubMed

    Liu, J C; Vylet, V

    2001-01-01

    A synchrotron radiation (SR) facility typically consists of an injector, a storage ring, and SR beamlines. The latter two features are unique to SR facilities, when compared to other types of accelerator facilities. The SR facilities have the characteristics of low injection beam power, but high stored beam power. The storage ring is generally above ground with people occupying the experimental floor around a normally thin concrete ring wall. This paper addresses the radiation issues, in particular the shielding design, associated with the storage ring and SR beamlines. Normal and abnormal beam losses for injection and stored beams, as well as typical storage ring operation, are described. Ring shielding design for photons and neutrons from beam losses in the ring is discussed. Radiation safety issues and shielding design for SR beamlines, considering gas bremsstrahlung and synchrotron radiation, are reviewed. Radiation source terms and the methodologies for shielding calculations are presented.

  2. Engineering of radiation of optically active molecules with chiral nano-meta-particles

    NASA Astrophysics Data System (ADS)

    Klimov, V. V.; Guzatov, D. V.; Ducloy, M.

    2012-02-01

    The radiation of an optically active (chiral) molecule placed near a chiral nanosphere is investigated. The optimal conditions for engineering of radiation of optically active (chiral) molecules with the help of chiral nanoparticles are derived. It is shown that for this purpose, the substance of the chiral particle must have both ɛ and μ negative (double negative material (DNG)) or negative μ and positive ɛ (μ negative material (MNG)). Our results pave the way to an effective engineering of radiation of "left" and "right" molecules and to creating pure optical devices for separation of drugs enantiomers.

  3. Sources of the strongest RF radiation from lightning

    NASA Technical Reports Server (NTRS)

    Levine, D. M.

    1979-01-01

    Experiments performed at the Kennedy Space Center, Florida during TRIP-78 identified sources of the strongest RF radiation from lightning in the HF-VHF frequency range. Measurements were made of electric field changes associated with RF radiation using a field change system triggered on the output of an RF detector. The field changes associated with the strongest RF radiation are very fast (10 - 20 microseconds), bipolar pulses having an initial negative going half-cycle followed by a positive overshoot. These fast pulses consistently produced more RF radiation than was associated with return strokes, and their shape was remarkably consistent, independent of frequency.

  4. ERLN Radiation Focus Area

    EPA Pesticide Factsheets

    As part of the Environmental Response Laboratory Network, the National Air and Radiation Environmental Laboratory (NAREL) here provides your laboratory with access to radiation-specific laboratory guidance documents and training courses.

  5. Radiation Protection Handbook

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A handbook which sets forth the Kennedy Space Center radiation protection policy is presented. The book also covers administrative direction and guidance on organizational and procedural requirements of the program. Only ionizing radiation is covered.

  6. Radiation Therapy for Cancer

    MedlinePlus

    ... treatment. The radiation may be delivered by a machine outside the body ( external-beam radiation therapy ), or ... by a computer linked to an x-ray machine. CT scans are often used in treatment planning ...

  7. Radiation and Pregnancy

    MedlinePlus

    ... amounts of radiation. Can radiation from the 2011 nuclear power plant accident in Japan affect you now in the United States? Since the Fukushima Daiichi nuclear power plant accident in Japan in 2011, very ...

  8. Fluorescent radiation converter

    NASA Technical Reports Server (NTRS)

    Viehmann, W. (Inventor)

    1981-01-01

    A fluorescence radiation converter is described which includes a substantially undoped optically transparent substrate and a waveshifter coating deposited on at least one portion of the substrate for absorption of radiation and conversion of fluorescent radiation. The coating is formed to substantially 1000 g/liter of a solvent, 70 to 200 g/liter of an organic polymer, and 0.2 to 25 g/liter of at least one organic fluorescent dye. The incoming incident radiation impinges on the coating. Radiation is absorbed by the fluorescent dye and is re-emitted as a longer wavelength radiation. Radiation is trapped within the substrate and is totally internally reflected by the boundary surface. Emitted radiation leaves the substrate ends to be detected.

  9. Radiation effects in space

    SciTech Connect

    Fry, R.J.M.

    1986-01-01

    The paper discusses the radiation environment in space that astronauts are likely to be exposed to. Emphasis is on proton and HZE particle effects. Recommendations for radiation protection guidelines are presented. (ACR)

  10. Radiation therapy -- skin care

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000735.htm Radiation therapy - skin care To use the sharing features ... this page, please enable JavaScript. When you have radiation treatment for cancer, you may have some changes ...

  11. Prostate Cancer (Radiation Therapy)

    MedlinePlus

    ... can include incontinence (inability to control urination) and impotence (inability to achieve erection). More recently, several centers ... Radiation therapy (either external radiation or brachytherapy) causes impotence in some men. The rate of impotence is ...

  12. Space Radiation Program Element

    NASA Technical Reports Server (NTRS)

    Krenek, Sam

    2008-01-01

    This poster presentation shows the various elements of the Space Radiation Program. It reviews the program requirements: develop and validate standards, quantify space radiation human health risks, mitigate risks through countermeasures and technologies, and treat and monitor unmitigated risks.

  13. Radiation Oncology Treatment Team

    MedlinePlus

    ... patients to be advocates. View more information Treatment Team Quick Links Meet the Treatment Team Radiation Oncologist ... as medical oncologists and surgeons to maximize radiation’s effectiveness. Radiation oncologists are the only physicians with the ...

  14. Inspecting Juno Radiation Vault

    NASA Image and Video Library

    2010-07-12

    A technician inspects the special radiation vault being installed atop the propulsion module of NASA Juno spacecraft; the vault has titanium walls to protect the spacecraft electronic brain and heart from Jupiter harsh radiation environment.

  15. Prostate Cancer (Radiation Therapy)

    MedlinePlus

    ... to three years. If I choose surgery, will radiation treatment still be required? If your surgery is ... option with your physician team. If I choose radiation therapy, will surgical treatment still be an option? ...

  16. What Is Radiation Shielding?

    NASA Image and Video Library

    Kerry Lee, NASA Orion radiation system manager, explains how radiation shielding is used to block harmful particles coming into the spacecraft without producing secondary particles that can cause e...

  17. Radiation Protection in Canada

    PubMed Central

    Williams, N.

    1965-01-01

    The main emphasis of a provincial radiation protection program is on ionizing radiation produced by machines, although assistance is given to the Federal Radiation Protection Division in its program relating to radioactive substances. The basis for the Saskatchewan program of radiation protection is the Radiological Health Act 1961. An important provision of the Act is annual registration of radiation equipment. The design of the registration form encourages a “do-it-yourself” radiation and electrical safety inspection. Installations are inspected every two years by a radiation health officer. Two hundred and twenty-one deficiencies were found during inspection of 224 items of radiation equipment, the commonest being failure to use personal film badges. Insufficient filtration of the beam, inadequate limitation of the beam, and unnecessary exposure of operators were other common faults. Physicians have a responsibility to weigh the potential advantages against the hazards when requesting radiographic or fluoroscopic procedures. PMID:14282164

  18. Radiation Measurements on Mars

    NASA Image and Video Library

    2013-12-09

    Micrograys are unit of measurement for absorbed radiation dose. The vertical axis is in micrograys per day. The RAD instrument on NASA Curiosity Mars rover monitors the natural radiation environment at the surface of Mars.

  19. Lowering Juno Radiation Vault

    NASA Image and Video Library

    2010-07-12

    Technicians lowered a special radiation vault onto the propulsion module of NASA Juno spacecraft. The vault will dramatically slow the aging effect radiation has on the electronics for the duration of the mission.

  20. Radiation from hard objects

    SciTech Connect

    Canavan, G.H.

    1997-02-01

    The inference of the diameter of hard objects is insensitive to radiation efficiency. Deductions of radiation efficiency from observations are very sensitive - possibly overly so. Inferences of the initial velocity and trajectory vary similarly, and hence are comparably sensitive.

  1. Cell Radiation Experiment System

    NASA Technical Reports Server (NTRS)

    Morrison, Dennis R.

    2010-01-01

    The cell radiation experiment system (CRES) is a perfused-cell culture apparatus, within which cells from humans or other animals can (1) be maintained in homeostasis while (2) being exposed to ionizing radiation during controlled intervals and (3) being monitored to determine the effects of radiation and the repair of radiation damage. The CRES can be used, for example, to determine effects of drug, radiation, and combined drug and radiation treatments on both normal and tumor cells. The CRES can also be used to analyze the effects of radiosensitive or radioprotectant drugs on cells subjected to radiation. The knowledge gained by use of the CRES is expected to contribute to the development of better cancer treatments and of better protection for astronauts, medical-equipment operators, and nuclear-power-plant workers, and others exposed frequently to ionizing radiation.

  2. Anti-damping effect of radiation reaction

    NASA Astrophysics Data System (ADS)

    Wang, G.; Li, H.; Shen, Y. F.; Yuan, X. Z.; Zi, J.

    2010-01-01

    The anti-damping effect of radiation reaction, which means the radiation reaction does non-negative work on a radiating charge, is investigated at length by using the Lorentz-Dirac equation (LDE) for the motion of a point charge respectively acted on by (a) a pure electric field, (b) a pure magnetic field and (c) the fields of an electromagnetic wave. We found that the curvature of the charge's trajectory plays an important role in the radiation reaction force, and the anti-damping effect cannot take place for the real macroscopic motions of a point charge. The condition for this anti-damping effect to take place is that the gradient of the external force field must exceed a certain value over the region of magnitude of the classical radius of massive charges (~10-15 m). Our results are potentially helpful to lessen the controversy on LDE and justify it as the correct classical equation describing the radiating charge's motion. If this anti-damping effect of LDE were a real existing physical process, it could serve as a mechanism within the context of classical electrodynamics for the stability of hydrogen atoms. Using the picture of an electron in quantum electrodynamics, namely the negative bare charge surrounded by the polarized positive charges of vacuum, we can obtain a reasonable explanation for the energy transferred to the electron during the occurrence of the anti-damping effect, on which the venerable work of Wheeler and Feynman has thrown some light.

  3. Metalinguistic Negation in English and Arabic

    ERIC Educational Resources Information Center

    Nedwick, Kelly M.

    2014-01-01

    Negation is a unique and fascinating property of human language which has been given extensive theoretical and typological treatment. One categorization divides negation use into metalinguistic negation and descriptive negation (Horn, 1985). Descriptive negation (DN) is the truth-functional semantic operator which has received the most attention…

  4. Metalinguistic Negation in English and Arabic

    ERIC Educational Resources Information Center

    Nedwick, Kelly M.

    2014-01-01

    Negation is a unique and fascinating property of human language which has been given extensive theoretical and typological treatment. One categorization divides negation use into metalinguistic negation and descriptive negation (Horn, 1985). Descriptive negation (DN) is the truth-functional semantic operator which has received the most attention…

  5. External radiation surveillance

    SciTech Connect

    Antonio, E.J.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report describes how external radiation was measured, how surveys were performed, and the results of these measurements and surveys. External radiation exposure rates were measured at locations on and off the Hanford Site using thermoluminescent dosimeters (TLD). External radiation and contamination surveys were also performed with portable radiation survey instruments at locations on and around the Hanford Site.

  6. Hybrid radiator cooling system

    DOEpatents

    France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

    2016-03-15

    A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

  7. Vacuum ultraviolet negative photoion spectroscopy of chloroform.

    PubMed

    Chen, Liu-Li; Xu, Yun-Feng; Feng, Qiang; Tian, Shan Xi; Liu, Fu-Yi; Shan, Xiao-Bin; Sheng, Liu-Si

    2011-05-05

    Negative ions Cl(-), Cl(2)(-), CCl(-), CHCl(-), and CCl(2)(-) are observed in vacuum-ultraviolet ion-pair photodissociations of chloroform (CCl(3)H) using the Hefei synchrotron radiation facility, and their ion production efficiency curves are recorded in the photon energy range of 10.00-21.50 eV. Two similar spectra of the isotope anions (35)Cl(-) and (37)Cl(-) indicate the following: Besides the strong bands corresponding to the electron transitions from valence to Rydberg orbitals converging to the ionic states, some additional peaks can be assigned with the energetically accessible multibody fragmentations; a distinct peak at photon energy 14.55 eV may be due to a cascade process (namely, the Cl(2) neutral fragment at the highly excited state D'2(3)Π(g) may be produced in the photodissociation of CCl(3)H, and then the Cl(-) anions are produced in the pulsed-field induced ion-pair dissociations of Cl(2) (D'2(3)Π(g))); two vibrational excitation progressions, nν(2)(+) and nν(2)(+) + ν(3)(+), and nν(4)(+) and nν(4)(+) + ν(2)(+), are observed around C̃ (2)E and D̃ (2)E ionic states, respectively. The enthalpies of the multibody fragmentations to Cl(2)(-), CCl(-), CHCl(-), and CCl(2)(-) are calculated with the thermochemistry data available in the literature, and these multibody ion-pair dissociation pathways are tentatively assigned in the respective anion production spectra.

  8. Spacecraft radiator systems

    NASA Technical Reports Server (NTRS)

    Anderson, Grant A. (Inventor)

    2012-01-01

    A spacecraft radiator system designed to provide structural support to the spacecraft. Structural support is provided by the geometric "crescent" form of the panels of the spacecraft radiator. This integration of radiator and structural support provides spacecraft with a semi-monocoque design.

  9. (Mis)Understanding Radiation

    SciTech Connect

    Schreiber, Stephen Bruce

    2016-02-10

    This set of slides discusses radiation and fears concerning it at a non-technical level. Included are some misconceptions and practical consequences resulting from these. The concept of radiation hormesis is explained. The author concludes that a number of significant societal benefits are being foregone because of overly cautious concerns about low-level radiation.

  10. Environmental Radiation Data

    EPA Pesticide Factsheets

    Environmental Radiation Data (ERD) is an electronic and print journal compiled and distributed quarterly by the Office of Radiation and Indoor Air's National Air and Radiation Environmental Laboratory (NAREL) in Montgomery, Alabama. It contains data from RadNet (previously known as ERAMS.)

  11. Radiation port dermatophytosis

    SciTech Connect

    Rosen, T.; Dupuy, J.; Maor, M.; Altman, A.

    1988-12-01

    We report two cases in which dermatophytic infection developed almost entirely within a radiation field mimicking an acute radiation effect. Radiotherapists and dermatologists should be aware of this possibility and be able to differentiate it from radiation dermatitis. Topical antifungal agents are the recommended treatment after diagnosis is established.

  12. Design and applications of negative index metamaterials

    NASA Astrophysics Data System (ADS)

    Lam, Tai Anh

    Electromagnetic Negative Index Metamaterials (NIM) exhibit many novel phenomena such as negative Snell's law, backward wave propagation, reverse Cerenkov radiation, and reverse Doppler effect. Predicted theoretically by Veselago in 1968 and experimentally demonstrated and verified barely a decade ago, it has enabled many proof-of-concept applications not achievable with ordinary materials. However, from a practical perspective, synthesis issues such as material designs and fabrication techniques need to be improved for NIM to be useful. The goal of this work is to investigate and realize the practical potentials of NIM. To achieve this goal, the physical properties of NIM and their implications are reviewed to establish a fundamental theoretical understanding and appreciation. Experimentally, the constituent unit cells that make possible the realization of NIM are described. Unit cell simulation, fabrication, testing, and material properties extraction techniques and tools are developed to form the basic building blocks. In addition to being able to achieve negative index of refractions, NIM can be used to realize a continuum of material values with independent control of elect is permittivity and magnetic permeability. This newly found capability enables the development of the related field of transformation optics. An electromagnetic cloaking device, one of the first major proof-of-concept devices only made possible by the advent of NIM and transformation optics is simulated to demonstrate NIM's versatility. A major effort of this work is the design, fabrication, and testing of a NIM lens to scan phased-array antenna beams to the horizon. Lens design and optimization tools are developed, and the transformation optics technique of conformal mapping is used to transform the lens from a curved geometry to a faceted buckyball shell for easier fabrication. Other NIM applications also investigated are coated dielectric spheres for isotropic NIM unit cells, flat

  13. Ionizing Radiation: The issue of radiation quality

    NASA Astrophysics Data System (ADS)

    Prise, Kevin; Schettino, Giuseppe

    Types of Ionising radiations are differentiated from each other by fundamental characteristics of their energy deposition patterns when they interact with biological materials. At the level of the DNA these non-random patterns drive differences in the yields and distributions of DNA damage patterns and specifically the production of clustered damage or complex lesions. The complex radiation fields found in space bring significant challenges for developing a mechanistic understanding of radiation effects from the perspective of radiation quality as these consist of a diverse range of particle and energy types unique to the space environment. Linear energy transfer, energy deposited per unit track length in units of keV per micron, has long been used as a comparator for different types of radiation but has limitations in that it is an average value. Difference in primary core ionizations relative to secondary delta ray ranges vary significantly with particle mass and energy leading to complex interrelationships with damage production at the cellular level. At the cellular level a greater mechanistic understanding is necessary, linking energy deposition patterns to DNA damage patterns and cellular response, to build appropriate biophysical models that are predictive for different radiation qualities and mixed field exposures. Defined studies using monoenergetic beams delivered under controlled conditions are building quantitative data sets of both initial and long term changes in cells as a basis for a great mechanistic understanding of radiation quality effects of relevance to not only space exposures but clinical application of ion-beams.

  14. Negative effects of positive reinforcement.

    PubMed

    Perone, Michael

    2003-01-01

    Procedures classified as positive reinforcement are generally regarded as more desirable than those classified as aversive-those that involve negative reinforcement or punishment. This is a crude test of the desirability of a procedure to change or maintain behavior. The problems can be identified on the basis of theory, experimental analysis, and consideration of practical cases. Theoretically, the distinction between positive and negative reinforcement has proven difficult (some would say the distinction is untenable). When the distinction is made purely in operational terms, experiments reveal that positive reinforcement has aversive functions. On a practical level, positive reinforcement can lead to deleterious effects, and it is implicated in a range of personal and societal problems. These issues challenge us to identify other criteria for judging behavioral procedures.

  15. Gram-negative flagella glycosylation.

    PubMed

    Merino, Susana; Tomás, Juan M

    2014-02-19

    Protein glycosylation had been considered as an eccentricity of a few bacteria. However, through advances in analytical methods and genome sequencing, it is now established that bacteria possess both N-linked and O-linked glycosylation pathways. Both glycosylation pathways can modify multiple proteins, flagellins from Archaea and Eubacteria being one of these. Flagella O-glycosylation has been demonstrated in many polar flagellins from Gram-negative bacteria and in only the Gram-positive genera Clostridium and Listeria. Furthermore, O-glycosylation has also been demonstrated in a limited number of lateral flagellins. In this work, we revised the current advances in flagellar glycosylation from Gram-negative bacteria, focusing on the structural diversity of glycans, the O-linked pathway and the biological function of flagella glycosylation.

  16. Negative-ion plasma sources

    NASA Astrophysics Data System (ADS)

    Sheehan, D. P.; Rynn, N.

    1988-08-01

    Three designs for negative-ion plasma sources are described. Two sources utilize metal hexafluorides such as SF6 and WF6 to scavenge electrons from electron-ion plasmas and the third relies upon surface ionization of alkali halide salts on heated alumina and zirconia. SF6 introduced into electron-ion plasmas yielded negative-ion plasma densities of 10 to the 10th/cu cm with low residual electron densities. On alumina, plasma densities of 10 to the 9th/cu cm were obtained for CsCl, CsI, and KI and 10 to the 9th/cu cm for KCl. On zirconia 10 to the 10th/cu cm densities were obtained for CsCl. For alkali halide sources, electron densities of less than about 10 to the -4th have been achieved.

  17. Gram-Negative Flagella Glycosylation

    PubMed Central

    Merino, Susana; Tomás, Juan M.

    2014-01-01

    Protein glycosylation had been considered as an eccentricity of a few bacteria. However, through advances in analytical methods and genome sequencing, it is now established that bacteria possess both N-linked and O-linked glycosylation pathways. Both glycosylation pathways can modify multiple proteins, flagellins from Archaea and Eubacteria being one of these. Flagella O-glycosylation has been demonstrated in many polar flagellins from Gram-negative bacteria and in only the Gram-positive genera Clostridium and Listeria. Furthermore, O-glycosylation has also been demonstrated in a limited number of lateral flagellins. In this work, we revised the current advances in flagellar glycosylation from Gram-negative bacteria, focusing on the structural diversity of glycans, the O-linked pathway and the biological function of flagella glycosylation. PMID:24557579

  18. Cosmology with negative absolute temperatures

    NASA Astrophysics Data System (ADS)

    Vieira, J. P. P.; Byrnes, Christian T.; Lewis, Antony

    2016-08-01

    Negative absolute temperatures (NAT) are an exotic thermodynamical consequence of quantum physics which has been known since the 1950's (having been achieved in the lab on a number of occasions). Recently, the work of Braun et al. [1] has rekindled interest in negative temperatures and hinted at a possibility of using NAT systems in the lab as dark energy analogues. This paper goes one step further, looking into the cosmological consequences of the existence of a NAT component in the Universe. NAT-dominated expanding Universes experience a borderline phantom expansion (w < -1) with no Big Rip, and their contracting counterparts are forced to bounce after the energy density becomes sufficiently large. Both scenarios might be used to solve horizon and flatness problems analogously to standard inflation and bouncing cosmologies. We discuss the difficulties in obtaining and ending a NAT-dominated epoch, and possible ways of obtaining density perturbations with an acceptable spectrum.

  19. Negative effects of positive reinforcement

    PubMed Central

    Perone, Michael

    2003-01-01

    Procedures classified as positive reinforcement are generally regarded as more desirable than those classified as aversive—those that involve negative reinforcement or punishment. This is a crude test of the desirability of a procedure to change or maintain behavior. The problems can be identified on the basis of theory, experimental analysis, and consideration of practical cases. Theoretically, the distinction between positive and negative reinforcement has proven difficult (some would say the distinction is untenable). When the distinction is made purely in operational terms, experiments reveal that positive reinforcement has aversive functions. On a practical level, positive reinforcement can lead to deleterious effects, and it is implicated in a range of personal and societal problems. These issues challenge us to identify other criteria for judging behavioral procedures. ImagesFigure 1Figure 2 PMID:22478391

  20. Radiative pion capture by C12.

    NASA Technical Reports Server (NTRS)

    Lam, W. C.; Gotow, K.; Macdonald, B.; Trower, W. P.; Anderson, D. K.

    1972-01-01

    The energy spectrum of neutrons from radiative pion capture by carbon is investigated. Radiative pion capture is identified by coincidence of a stop signal and a signal from one of six lead-glass gamma detectors when negative pions traverse a beam telescope and are stopped in a carbon target. The energy of the neutrons is measured using the time interval between a stop signal coincident with a gamma-counter signal and a signal from a liquid-oscillator neutron counter. Asymmetry in the neutron-photon angular correlation increases with neutron energy and is accounted for by direct neutron emission.

  1. Radiative pion capture by C12.

    NASA Technical Reports Server (NTRS)

    Lam, W. C.; Gotow, K.; Macdonald, B.; Trower, W. P.; Anderson, D. K.

    1972-01-01

    The energy spectrum of neutrons from radiative pion capture by carbon is investigated. Radiative pion capture is identified by coincidence of a stop signal and a signal from one of six lead-glass gamma detectors when negative pions traverse a beam telescope and are stopped in a carbon target. The energy of the neutrons is measured using the time interval between a stop signal coincident with a gamma-counter signal and a signal from a liquid-oscillator neutron counter. Asymmetry in the neutron-photon angular correlation increases with neutron energy and is accounted for by direct neutron emission.

  2. Triple-Negative Breast Carcinoma.

    PubMed

    Livasy, Chad A

    2009-06-01

    Triple-negative breast carcinomas (TNBCs) comprise approximately 15% to 20% of breast cancers. Accurate assessment of tumor estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2) status is an essential part of classifying tumors into this group. As a group, these tumors are associated with poor clinical outcomes and have been shown to exhibit an increased propensity for hematogenous metastasis to the brain and lungs. Many TNBCs, particularly ductal, not otherwise specified (NOS), and metaplastic carcinomas, show an overlapping characteristic gene expression pattern when evaluated by cDNA microarrays. This group has been termed basal-like because of the similarity with normal breast basal/myoepithelial cells including basal cytokeratin expression and lack of hormone receptor and HER2 expression. The array data have been used to develop multiple immunohistochemical surrogates to identify basal-like tumors in formalin-fixed, paraffin-embedded tissues, most employing basal cytokeratins and epidermal growth factor receptor. Currently, there is no international consensus on biomarkers used to identify tumors as basal-like, and the routine use of the term basal-like in surgical pathology reports is premature. Tumor morphologic features associated with triple-negative status include Nottingham grade 3 with high mitotic rate, pushing border of invasion, geographic tumor necrosis, solid/sheet-like growth pattern, lymphocytic infiltrate, and large central acellular zone. Most breast cancers arising in patients who have a germ-line BRCA1 mutation show similar histologic features and a triple-negative phenotype. Not all TNBCs are associated with an unfavorable prognosis, drawing attention to the heterogeneity of this tumor group and the continued need to link tumor morphology and grade with triple-negative status. This article focuses on histopathology, molecular characterization, carcinogenesis, clinical behavior, and treatment of these

  3. Quantum complexity and negative curvature

    NASA Astrophysics Data System (ADS)

    Brown, Adam R.; Susskind, Leonard; Zhao, Ying

    2017-02-01

    As time passes, once simple quantum states tend to become more complex. For strongly coupled k -local Hamiltonians, this growth of computational complexity has been conjectured to follow a distinctive and universal pattern. In this paper we show that the same pattern is exhibited by a much simpler system—classical geodesics on a compact two-dimensional geometry of uniform negative curvature. This striking parallel persists whether the system is allowed to evolve naturally or is perturbed from the outside.

  4. In defense of negative temperature

    NASA Astrophysics Data System (ADS)

    Poulter, J.

    2016-03-01

    This pedagogical comment highlights three misconceptions concerning the usefulness of the concept of negative temperature, being derived from the usual, often termed Boltzmann, definition of entropy. First, both the Boltzmann and Gibbs entropies must obey the same thermodynamic consistency relation. Second, the Boltzmann entropy does obey the second law of thermodynamics. Third, there exists an integrating factor of the heat differential with both definitions of entropy.

  5. Negative refraction in semiconductor metamaterials.

    PubMed

    Hoffman, Anthony J; Alekseyev, Leonid; Howard, Scott S; Franz, Kale J; Wasserman, Dan; Podolskiy, Viktor A; Narimanov, Evgenii E; Sivco, Deborah L; Gmachl, Claire

    2007-12-01

    An optical metamaterial is a composite in which subwavelength features, rather than the constituent materials, control the macroscopic electromagnetic properties of the material. Recently, properly designed metamaterials have garnered much interest because of their unusual interaction with electromagnetic waves. Whereas nature seems to have limits on the type of materials that exist, newly invented metamaterials are not bound by such constraints. These newly accessible electromagnetic properties make these materials an excellent platform for demonstrating unusual optical phenomena and unique applications such as subwavelength imaging and planar lens design. 'Negative-index materials', as first proposed, required the permittivity, epsilon, and permeability, mu, to be simultaneously less than zero, but such materials face limitations. Here, we demonstrate a comparatively low-loss, three-dimensional, all-semiconductor metamaterial that exhibits negative refraction for all incidence angles in the long-wave infrared region and requires only an anisotropic dielectric function with a single resonance. Using reflection and transmission measurements and a comprehensive model of the material, we demonstrate that our material exhibits negative refraction. This is furthermore confirmed through a straightforward beam optics experiment. This work will influence future metamaterial designs and their incorporation into optical semiconductor devices.

  6. Exotic negative molecules in AMS

    NASA Astrophysics Data System (ADS)

    Golser, Robin; Gnaser, Hubert; Kutschera, Walter; Priller, Alfred; Steier, Peter; Wallner, Anton

    2007-06-01

    "The techniques and equipment developed for AMS studies are well suited for identifying exotic negative ions". With this sentence begins a pioneering paper by Roy Middleton and Jeff Klein (M&K) on small doubly-charged negative carbon clusters [Nucl. Instr. and Meth. B 123 (1997) 532]. M&K were the first to utilize Accelerator Mass Spectrometry to prove the existence of these clusters and a number of other exotic molecules. We review M&K's efforts and show how their work is being continued at other laboratories. The latest developments are: (1) the discovery of long-lived molecular hydrogen anions H2-,D2-and (2) the unambiguous identification of the smallest doubly-charged negative molecule (LiF3)2-. In particular we show new experimental data for D3-, and for (LiF3)2-, and we try to answer the question why M&K's search for this di-anion was unsuccessful.

  7. Acoustic metamaterial with negative parameter

    NASA Astrophysics Data System (ADS)

    Sun, Hongwei; Yan, Fei; Gu, Hao; Li, Ying

    2014-03-01

    In this paper we present theoretical results on an acoustic metamaterial beam and a bar that exhibit negative effective mass and negative effective stiffness. A one-dimensional acoustic metamaterial with an array of spring-mass subsystems was fabricated. The frequency of the acoustic one dimensional metamaterial structure has the same form as that of the permittivity in metals due to the plasma oscillation. We also provide a theory to explain the simulation results. And we use the concept of conventional mechanical vibration absorbers to reveal the actual working mechanism of the acoustic metamaterials. We explain the two vibrate modes which are optical mode and acoustic mode in detail. When the incoming elastic wave in the acoustic metamaterials to resonate the integrated spring-mass-damper absorbers to vibrate in their optical mode at frequencies close to but above their local resonance frequencies to create shear forces and bending moments to straighten the beam and stop the wave propagation. Moreover, we explain the negative parameter in acoustic metamaterials.

  8. Negative Reflecting Meta-Mirrors.

    PubMed

    Yang, Rui; Li, Dong; Gao, Dongxing; Zhang, Aofang; Hu, Bowei; Yang, Pei; Lei, Zhenya; Li, Jiacheng

    2017-07-18

    Using the gradient phase discontinuities that meta-mirrors provide, we show that the incident wave can be reflected anomalously with a broad angle range of negative reflections. Such reversed behaviors promote the immediate applications for the planar meta-mirrors to steer the signals more arbitrarily and the convex meta-mirrors to focus and collimate electromagnetic fields. We practically implement these negative reflecting meta-mirrors through an arrangement of subwavelength ring patches and generate the desired phase distribution by also considering the incident angle. Finally, the experiments are carried out to verify the functionality of the convex meta-mirror firstly, and the performances of the planar meta-mirror are also tested by further building up a dual reflector system with the demonstration of obtaining the plane wave from the convex meta-mirror and then having the well collimated beam negative reflected by the planar meta-mirror. The proposed design should be readily applicable to a wide range of electromagnetic problems, especially for devising smart planar illusion devices, and highly directive antennas mounting on convex surfaces of various platforms.

  9. Research priorities for negative emissions

    NASA Astrophysics Data System (ADS)

    Fuss, S.; Jones, C. D.; Kraxner, F.; Peters, G. P.; Smith, P.; Tavoni, M.; van Vuuren, D. P.; Canadell, J. G.; Jackson, R. B.; Milne, J.; Moreira, J. R.; Nakicenovic, N.; Sharifi, A.; Yamagata, Y.

    2016-11-01

    Carbon dioxide removal from the atmosphere (CDR)—also known as ‘negative emissions’—features prominently in most 2 °C scenarios and has been under increased scrutiny by scientists, citizens, and policymakers. Critics argue that ‘negative emission technologies’ (NETs) are insufficiently mature to rely on them for climate stabilization. Some even argue that 2 °C is no longer feasible or might have unacceptable social and environmental costs. Nonetheless, the Paris Agreement endorsed an aspirational goal of limiting global warming to even lower levels, arguing that climate impacts—especially for vulnerable nations such as small island states—will be unacceptably severe in a 2 °C world. While there are few pathways to 2 °C that do not rely on negative emissions, 1.5 °C scenarios are barely conceivable without them. Building on previous assessments of NETs, we identify some urgent research needs to provide a more complete picture for reaching ambitious climate targets, and the role that NETs can play in reaching them.

  10. Altitude, radiation, and mortality from cancer and heart disease

    SciTech Connect

    Weinberg, C.R.; Brown, K.G.; Hoel, D.G.

    1987-11-01

    The variation in background radiation levels is an important source of information for estimating human risks associated with low-level exposure to ionizing radiation. Several studies conducted in the United States, correlating mortality rates for cancer with estimated background radiation levels, found an unexpected inverse relationship. Such results have been interpreted as suggesting that low levels of ionizing radiation may actually confer some benefit. An environmental factor strongly correlated with background radiation is altitude. Since there are important physiological adaptations associated with breathing thinner air, such changes may themselves influence risk. We therefore fit models that simultaneously incorporated altitude and background radiation as predictors of mortality. The negative correlations with background radiation seen for mortality from arteriosclerotic heart disease and cancers of the lung, the intestine, and the breast disappeared or became positive once altitude was included in the models. By contrast, the significant negative correlations with altitude persisted with adjustment for radiation. Interpretation of these results is problematic, but recent evidence implicating reactive forms of oxygen in carcinogenesis and atherosclerosis may be relevant. We conclude that the cancer correlational studies carried out in the United States using vital statistics data do not in themselves demonstrate a lack of carcinogenic effect of low radiation levels, and that reduced oxygen pressure of inspired air may be protective against certain causes of death.

  11. Radiation Therapy: Additional Treatment Options

    MedlinePlus

    ... Upper GI What is Radiation Therapy? Find a Radiation Oncologist Last Name: Facility: City: State: Zip Code: ... infections. This is refered to as immunotherapy . Intraoperative Radiation Therapy Radiation therapy given during surgery is called ...

  12. Solar radiation measurement project

    NASA Technical Reports Server (NTRS)

    Ioup, J. W.

    1981-01-01

    The Xavier solar radiation measurement project and station are described. Measurements of the total solar radiation on a horizontal surface from an Eppley pyranometer were collected into computer data files. Total radiation in watt hours was converted from ten minute intervals to hourly intervals. Graphs of this total radiation data are included. A computer program in Fortran was written to calculate the total extraterrestrial radiation on a horizontal surface for each day of the month. Educational and social benefits of the project are cited.

  13. Radiation protection in space

    SciTech Connect

    Blakely, E.A.; Fry, R.J.M.

    1995-02-01

    The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in the present state of knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared to previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space.

  14. Solar cell radiation handbook

    NASA Technical Reports Server (NTRS)

    Carter, J. R., Jr.; Tada, H. Y.

    1973-01-01

    A method is presented for predicting the degradation of a solar array in a space radiation environment. Solar cell technology which emphasizes the cell parameters that degrade in a radiation environment, is discussed along with the experimental techniques used in the evaluation of radiation effects. Other topics discussed include: theoretical aspects of radiation damage, methods for developing relative damage coefficients, nature of the space radiation environment, method of calculating equivalent fluence from electron and proton energy spectrums and relative damage coefficients, and comparison of flight data with estimated degradation.

  15. Radiation detection system

    DOEpatents

    Nelson, Melvin A.; Davies, Terence J.; Morton, III, John R.

    1976-01-01

    A radiation detection system which utilizes the generation of Cerenkov light in and the transmission of that light longitudinally through fiber optic wave guides in order to transmit intelligence relating to the radiation to a remote location. The wave guides are aligned with respect to charged particle radiation so that the Cerenkov light, which is generated at an angle to the radiation, is accepted by the fiber for transmission therethrough. The Cerenkov radiation is detected, recorded, and analyzed at the other end of the fiber.

  16. RADIATION WAVE DETECTOR

    DOEpatents

    Wouters, L.F.

    1958-10-28

    The detection of the shape and amplitude of a radiation wave is discussed, particularly an apparatus for automatically indicating at spaced lntervals of time the radiation intensity at a flxed point as a measure of a radiation wave passing the point. The apparatus utilizes a number of photomultiplier tubes surrounding a scintillation type detector, For obtainlng time spaced signals proportional to radiation at predetermined intervals the photolnultiplier tubes are actuated ln sequence following detector incidence of a predetermined radiation level by electronic means. The time spaced signals so produced are then separately amplified and relayed to recording means.

  17. PERSONAL RADIATION MONITOR

    DOEpatents

    Dilworth, R.H.; Borkowski, C.J.

    1961-12-26

    A transistorized, fountain pen type radiation monitor to be worn on the person is described. Radiation produces both light flashes in a small bulb and an audible warning tone, the frequency of both the tone and light flashes being proportional to radiation intensity. The device is powered by a battery and a blocking oscillator step-up power supply The oscillator frequency- is regulated to be proportional to the radiation intensity, to provide adequate power in high radiation fields, yet minimize battery drain at low operating intensities. (AEC)

  18. Negative elevation-dependent warming trend in the Eastern Alps

    NASA Astrophysics Data System (ADS)

    Tudoroiu, M.; Eccel, E.; Gioli, B.; Gianelle, D.; Schume, H.; Genesio, L.; Miglietta, F.

    2016-04-01

    Mountain regions and the important ecosystem services they provide are considered to be very vulnerable to the current warming, and recent studies suggest that high-mountain environments experience more rapid changes in temperature than environments at lower elevations. Here we analysed weather records for the period 1975-2010 from the Eastern Italian Alps that show that warming occurred both at high and low elevations, but it was less pronounced at high elevations. This negative elevation-dependent trend was consistent for mean, maximum and minimum air temperature. Global radiation data measured at different elevations, surface energy fluxes measured above an alpine grassland and above a coniferous forest located at comparable elevations for nine consecutive years as well as remote sensing data (MODIS) for cloud cover and aerosol optical depth were analysed to interpret this observation. Increasing global radiation at low elevations turned out to be a potential driver of this negative elevation-dependent warming, but also contributions from land use and land cover changes at high elevations (abandonment of alpine pastures, expansion of secondary forest succession) were taken into account. We emphasise though, that a negative elevation-dependent warming is not universal and that future research and in particular models should not neglect the role of land use changes when determining warming rates over elevation.

  19. COHERENCE PROPERTIES OF ELECTROMAGNETIC RADIATION,

    DTIC Science & Technology

    ELECTROMAGNETIC RADIATION , COHERENT SCATTERING), (*COHERENT SCATTERING, ELECTROMAGNETIC RADIATION ), LIGHT, INTERFERENCE, INTENSITY, STATISTICAL FUNCTIONS, QUANTUM THEORY, BOSONS, INTERFEROMETERS, CHINA

  20. Radiation curing of epoxies

    NASA Astrophysics Data System (ADS)

    Dickson, Lawrence W.; Singh, Ajit

    The literature on radiation polymerization of epoxy compounds has been reviewed to assess the potential use of radiation for curing these industrially important monomers. Chemical curing of epoxies may proceed by either cationic or anionic mechanisms depending on the nature of the curing agent, but most epoxies polymerize by cationic mechanisms under the influence of high-energy radiation. Radiation-induced cationic polymerization of epoxy compounds is inhibited by trace quantities of water because of proton transfer from the chain-propagating epoxy cation to water. Several different methods with potential for obtaining high molecular weight polymers by curing epoxies with high-energy radiation have been studied. Polymeric products with epoxy-like properties have been produced by radiation curing of epoxy oligomers with terminal acrylate groups and mixtures of epoxies with vinyl monomers. Both of these types of resin have good potential for industrial-scale curing by radiation treatment.

  1. Radiation-induced gliomas

    PubMed Central

    Prasad, Gautam; Haas-Kogan, Daphne A.

    2013-01-01

    Radiation-induced gliomas represent a relatively rare but well-characterized entity in the neuro-oncologic literature. Extensive retrospective cohort data in pediatric populations after therapeutic intracranial radiation show a clearly increased risk in glioma incidence that is both patient age- and radiation dose/volume-dependent. Data in adults are more limited but show heightened risk in certain groups exposed to radiation. In both populations, there is no evidence linking increased risk associated with routine exposure to diagnostic radiation. At the molecular level, recent studies have found distinct genetic differences between radiation-induced gliomas and their spontaneously-occurring counterparts. Clinically, there is understandable reluctance on the part of clinicians to re-treat patients due to concern for cumulative neurotoxicity. However, available data suggest that aggressive intervention can lead to improved outcomes in patients with radiation-induced gliomas. PMID:19831840

  2. Americans' Average Radiation Exposure

    SciTech Connect

    NA

    2000-08-11

    We live with radiation every day. We receive radiation exposures from cosmic rays, from outer space, from radon gas, and from other naturally radioactive elements in the earth. This is called natural background radiation. It includes the radiation we get from plants, animals, and from our own bodies. We also are exposed to man-made sources of radiation, including medical and dental treatments, television sets and emission from coal-fired power plants. Generally, radiation exposures from man-made sources are only a fraction of those received from natural sources. One exception is high exposures used by doctors to treat cancer patients. Each year in the United States, the average dose to people from natural and man-made radiation sources is about 360 millirem. A millirem is an extremely tiny amount of energy absorbed by tissues in the body.

  3. RF radiation from lightning

    NASA Technical Reports Server (NTRS)

    Levine, D. M.

    1978-01-01

    Radiation from lightning in the RF band from 3-300 MHz were monitored. Radiation in this frequency range is of interest as a potential vehicle for monitoring severe storms and for studying the lightning itself. Simultaneous measurements were made of RF radiation and fast and slow field changes. Continuous analogue recordings with a system having 300 kHz of bandwidth were made together with digital records of selected events (principally return strokes) at greater temporal resolution. The data reveal patterns in the RF radiation for the entire flash which are characteristic of flash type and independent of the frequency of observation. Individual events within the flash also have characteristic RF patterns. Strong radiation occurs during the first return strokes, but delayed about 20 micron sec with respect to the begining of the return stroke; whereas, RF radiation from subsequent return strokes tends to be associated with cloud processes preceding the flash with comparatively little radiation occurring during the return stroke itself.

  4. Acute radiation syndrome and chronic radiation syndrome.

    PubMed

    Grammaticos, Philip; Giannoula, Evanthia; Fountos, George P

    2013-01-01

    Acute radiation syndrome (ARS) or sickness or poisoning or toxicity is induced after a whole body exposure of men to high doses of radiation between 1-12Gy. First symptoms are from the gastrointestinal system, which together with bone marrow are the most sensitive parts of our body. Chronic radiation syndrome (CRS) may be induced by smaller than 1Gy radiation doses or after a mild form of ARS. Prophylaxis and treatment suggestions are described. In cases of ARS, a large part of the exposed population after proper medical care may survive, while without medical care this part of the population will be lost. Prophylaxis may also save another part of the population.

  5. The Radiation Transport Conundrum in Radiation Hydrodynamics

    SciTech Connect

    Castor, J I

    2005-03-18

    The summary of this paper is: (1) The conundrum in the title is whether to treat radiation in the lab frame or the comoving frame in a radiation-hydrodynamic problem; (2) Several of the difficulties are associated with combining a somewhat relativistic treatment of radiation with a non-relativistic treatment of hydrodynamics; (3) The principal problem is a tradeoff between easily obtaining the correct diffusion limit and describing free-streaming radiation with the correct wave speed; (4) The computational problems of the comoving-frame formulation in more than one dimension, and the difficulty of obtaining both exact conservation and full u/c accuracy argue against this method; (5) As the interest in multi-D increases, as well as the power of computers, the lab-frame method is becoming more attractive; and (6) The Monte Carlo method combines the advantages of both lab-frame and comoving-frame approaches, its only disadvantage being cost.

  6. Pathophysiology, diagnosis, and treatment of radiation necrosis in the brain.

    PubMed

    Miyatake, Shin-Ichi; Nonoguchi, Noasuke; Furuse, Motomasa; Yoritsune, Erina; Miyata, Tomo; Kawabata, Shinji; Kuroiwa, Toshihiko

    2015-01-01

    New radiation modalities have made it possible to prolong the survival of individuals with malignant brain tumors, but symptomatic radiation necrosis becomes a serious problem that can negatively affect a patient's quality of life through severe and lifelong effects. Here we review the relevant literature and introduce our original concept of the pathophysiology of brain radiation necrosis following the treatment of brain, head, and neck tumors. Regarding the pathophysiology of radiation necrosis, we introduce two major hypotheses: glial cell damage or vascular damage. For the differential diagnosis of radiation necrosis and tumor recurrence, we focus on the role of positron emission tomography. Finally, in accord with our hypothesis regarding the pathophysiology, we describe the promising effects of the anti-vascular endothelial growth factor antibody bevacizumab on symptomatic radiation necrosis in the brain.

  7. Pathophysiology, Diagnosis, and Treatment of Radiation Necrosis in the Brain.

    PubMed

    Miyatake, Shin-Ichi; Nonoguchi, Noasuke; Furuse, Motomasa; Yoritsune, Erina; Miyata, Tomo; Kawabata, Shinji; Kuroiwa, Toshihiko

    2015-01-01

    New radiation modalities have made it possible to prolong the survival of individuals with malignant brain tumors, but symptomatic radiation necrosis becomes a serious problem that can negatively affect a patient’s quality of life through severe and lifelong effects. Here we review the relevant literature and introduce our original concept of the pathophysiology of brain radiation necrosis following the treatment of brain, head, and neck tumors. Regarding the pathophysiology of radiation necrosis, we introduce two major hypotheses: glial cell damage or vascular damage. For the differential diagnosis of radiation necrosis and tumor recurrence, we focus on the role of positron emission tomography. Finally, in accord with our hypothesis regarding the pathophysiology, we describe the promising effects of the anti-vascular endothelial growth factor antibody bevacizumab on symptomatic radiation necrosis in the brain.

  8. High-power radiating plasma

    NASA Technical Reports Server (NTRS)

    Rozanov, V. B.; Rukhadze, A. A.

    1984-01-01

    The physical principles underlying the use of radiating plasmas for the optical pumping of lasers are described. Particular consideration is given to the properties of radiating plasmas; radiation selectivity; the dynamics, equilibrium, and stability of radiating plasmas; the radiative Reynolds number; and experimental results on radiating discharges.

  9. Coagulase-negative staphylococcal infections.

    PubMed

    Rogers, Kathie L; Fey, Paul D; Rupp, Mark E

    2009-03-01

    Coagulase-negative staphylococci (CNS) are differentiated from the closely related but more virulent Staphylococcus aureus by their inability to produce free coagulase. Currently, there are over 40 recognized species of CNS. These organisms typically reside on healthy human skin and mucus membranes, rarely cause disease, and are most frequently encountered by clinicians as contaminants of microbiological cultures. However, CNS have been increasingly recognized to cause clinically significant infections. The conversion of the CNS from symbiont to human pathogen has been a direct reflection of the use of indwelling medical devices. This article deals with the clinical syndromes, epidemiology, prevention, and management of infections caused by this unique group of organisms.

  10. Acoustic metamaterial with negative modulus.

    PubMed

    Lee, Sam Hyeon; Park, Choon Mahn; Seo, Yong Mun; Wang, Zhi Guo; Kim, Chul Koo

    2009-04-29

    We present experimental and theoretical results on an acoustic metamaterial that exhibits a negative effective modulus in a frequency range from 0 to 450 Hz. A one-dimensional acoustic metamaterial with an array of side holes on a tube was fabricated. We observed that acoustic waves above 450 Hz propagated well in this structure, but no sound below 450 Hz passed through. The frequency characteristics of the metamaterial has the same form as that of the permittivity in metals due to the plasma oscillation. We also provide a theory to explain the experimental results.

  11. Negative mass solitons in gravity

    SciTech Connect

    Cebeci, Hakan; Sarioglu, Oezguer; Tekin, Bayram

    2006-03-15

    We first reconstruct the conserved (Abbott-Deser) charges in the spin-connection formalism of gravity for asymptotically (Anti)-de Sitter spaces, and then compute the masses of the AdS soliton and the recently found Eguchi-Hanson solitons in generic odd dimensions, unlike the previous result obtained for only five dimensions. These solutions have negative masses compared to the global AdS or AdS/Z{sub p} spacetimes. As a separate note, we also compute the masses of the recent even dimensional Taub-NUT-Reissner-Nordstroem metrics.

  12. Infrared negative luminescent devices and higher operating temperature detectors

    NASA Astrophysics Data System (ADS)

    Nash, G. R.; Gordon, N. T.; Hall, D. J.; Ashby, M. K.; Little, J. C.; Masterton, G.; Hails, J. E.; Giess, J.; Haworth, L.; Emeny, M. T.; Ashley, T.

    2004-01-01

    Infrared LEDs and negative luminescent devices, where less light is emitted than in equilibrium, have been attracting an increasing amount of interest recently. They have a variety of applications, including as a ‘source’ of IR radiation for gas sensing; radiation shielding for, and non-uniformity correction of, high sensitivity staring infrared detectors; and dynamic infrared scene projection. Similarly, infrared (IR) detectors are used in arrays for thermal imaging and, discretely, in applications such as gas sensing. Multi-layer heterostructure epitaxy enables the growth of both types of device using designs in which the electronic processes can be precisely controlled and techniques such as carrier exclusion and extraction can be implemented. This enables detectors to be made which offer good performance at higher than normal operating temperatures, and efficient negative luminescent devices to be made which simulate a range of effective temperatures whilst operating uncooled. In both cases, however, additional performance benefits can be achieved by integrating optical concentrators around the diodes to reduce the volume of semiconductor material, and so minimise the thermally activated generation-recombination processes which compete with radiative mechanisms. The integrated concentrators are in the form of Winston cones, which can be formed using an iterative dry etch process involving methane/hydrogen and oxygen. We present results on negative luminescence in the mid- and long-IR wavebands, from devices made from indium antimonide and mercury cadmium telluride, where the aim is sizes greater than 1 cm×1 cm. We also discuss progress on, and the potential for, operating temperature and/or sensitivity improvement of detectors, where very high-performance imaging is anticipated from systems which require no mechanical cooling.

  13. Infrared negative luminescent devices and higher operating temperature detectors

    NASA Astrophysics Data System (ADS)

    Nash, Geoff R.; Gordon, Neil T.; Hall, David J.; Little, J. Chris; Masterton, G.; Hails, J. E.; Giess, J.; Haworth, L.; Emeny, Martin T.; Ashley, Tim

    2004-02-01

    Infrared LEDs and negative luminescent devices, where less light is emitted than in equilibrium, have been attracting an increasing amount of interest recently. They have a variety of applications, including as a ‘source" of IR radiation for gas sensing; radiation shielding for and non-uniformity correction of high sensitivity starring infrared detectors; and dynamic infrared scene projection. Similarly, IR detectors are used in arrays for thermal imaging and, discretely, in applications such as gas sensing. Multi-layer heterostructure epitaxy enables the growth of both types of device using designs in which the electronic processes can be precisely controlled and techniques such as carrier exclusion and extraction can be implemented. This enables detectors to be made which offer good performance at higher than normal operating temperatures, and efficient negative luminescent devices to be made which simulate a range of effective temperatures whilst operating uncooled. In both cases, however, additional performance benefits can be achieved by integrating optical concentrators around the diodes to reduce the volume of semiconductor material, and so minimise the thermally activated generation-recombination processes which compete with radiative mechanisms. The integrated concentrators are in the form of Winston cones, which can be formed using an iterative dry etch process involving methane/hydrogen and oxygen. We will present results on negative luminescence in the mid and long IR wavebands, from devices made from indium antimonide and mercury cadmium telluride, where the aim is sizes greater than 1cm x 1cm. We will also discuss progress on, and the potential for, operating temperature and/or sensitivity improvement of detectors, where very higher performance imaging is anticipated from systems which require no mechanical cooling.

  14. Infrared Negative Luminescent Devices and Higher Operating Temperature Detectors

    NASA Astrophysics Data System (ADS)

    Ashley, Tim

    2003-03-01

    Infrared LEDs and negative luminescent devices, where less light is emitted than in equilibrium, have been attracting an increasing amount of interest recently. They have a variety of applications, including as a source' of IR radiation for gas sensing; radiation shielding for and non-uniformity correction of high sensitivity starring infrared detectors; and dynamic infrared scene projection. Similarly, IR detectors are used in arrays for thermal imaging and, discretely, in applications such as gas sensing. Multi-layer heterostructure epitaxy enables the growth of both types of device using designs in which the electronic processes can be precisely controlled and techniques such as carrier exclusion and extraction can be implemented. This enables detectors to be made which offer good performance at higher than normal operating temperatures, and efficient negative luminescent devices to be made which simulate a range of effective temperatures whilst operating uncooled. In both cases, however, additional performance benefits can be achieved by integrating optical concentrators around the diodes to reduce the volume of semiconductor material, and so minimise the thermally activated generation-recombination processes which compete with radiative mechanisms. The integrated concentrators are in the form of Winston cones, which can be formed using an iterative dry etch process involving methane/hydrogen and oxygen. We will present results on negative luminescence in the mid and long IR wavebands, from devices made from indium antimonide and mercury cadmium telluride, where the aim is sizes greater than 1cm x 1cm. We will also discuss progress on, and the potential for, operating temperature and/or sensitivity improvement of detectors, where very high performance imaging is anticipated from systems which require no mechanical cooling.

  15. Complications of radiation therapy

    SciTech Connect

    Dalinka, M.K.; Mazzeo, V.P. Jr.

    1985-01-01

    The skeletal effects of radiation are dependent upon many variables, but the pathologic features are consistent. Radiation may cause immediate or delayed cell death, cellular injury with recovery, arrest of cellular division, or abnormal repair with neoplasia. Radiation necrosis and radiation-induced neoplasm still occur despite the use of supervoltage therapy. Complications of radiotherapy are well known and have led to more judicious use of this therapeutic modality. With few exceptions, benign bone tumors are no longer treated with irradiation. Radiation necrosis may be difficult to differentiate from sarcoma arising in irradiated bone. They both occur within the field of irradiation. Radiation necrosis often has a long latent period which is, of course, the rule in radiation-induced neoplasia. A soft tissue mass favors the diagnosis of neoplasia, while its absence suggests radiation necrosis. Lack of pain favors necrosis. Calcification may occur in radiation necrosis and does not indicate neoplasia. A lack of progression on serial roentgenograms also favors radiation necrosis. 76 references.

  16. Thermal radiation measuring arrangement

    SciTech Connect

    Berman, H.L.; Sprout, J.C.

    1983-02-08

    In a thermal radiation measuring arrangement, a thermal radiation detector is located at the focal point of a collecting mirror, upon which incident thermal radiation from a surface, such as a building wall, is directed. The thermal radiation detector may be, for example, a thermopile, and provides an output signal having a magnitude proportional to the amount of thermal radiation which it receives. The temperature detection means detects the temperature of the thermal radiation detector and, for example, may detect the cold junction of the thermopile. In a first operating condition, a signal summing means receives the output signal from the thermal radiation detector and the temperature detection means and provides a third output signal proportional to the sum of these first and second output signals. In a second operating condition, a signal biasing means is connected into the signal summing means. The signal biasing means provides a signal to the signal summing means to cause the third output signal to become zero when radiation is received from a reference surface. When the arrangement is in the second operating condition and directed to receive thermal radiation from a second surface different from the reference surface, the signal biasing means maintains the same level of bias to the signal summing means as it did when detecting the radiation from the reference surface.

  17. Dynamically variable negative stiffness structures

    PubMed Central

    Churchill, Christopher B.; Shahan, David W.; Smith, Sloan P.; Keefe, Andrew C.; McKnight, Geoffrey P.

    2016-01-01

    Variable stiffness structures that enable a wide range of efficient load-bearing and dexterous activity are ubiquitous in mammalian musculoskeletal systems but are rare in engineered systems because of their complexity, power, and cost. We present a new negative stiffness–based load-bearing structure with dynamically tunable stiffness. Negative stiffness, traditionally used to achieve novel response from passive structures, is a powerful tool to achieve dynamic stiffness changes when configured with an active component. Using relatively simple hardware and low-power, low-frequency actuation, we show an assembly capable of fast (<10 ms) and useful (>100×) dynamic stiffness control. This approach mitigates limitations of conventional tunable stiffness structures that exhibit either small (<30%) stiffness change, high friction, poor load/torque transmission at low stiffness, or high power active control at the frequencies of interest. We experimentally demonstrate actively tunable vibration isolation and stiffness tuning independent of supported loads, enhancing applications such as humanoid robotic limbs and lightweight adaptive vibration isolators. PMID:26989771

  18. Serotonin, Inhibition, and Negative Mood

    PubMed Central

    Dayan, Peter; Huys, Quentin J. M

    2008-01-01

    Pavlovian predictions of future aversive outcomes lead to behavioral inhibition, suppression, and withdrawal. There is considerable evidence for the involvement of serotonin in both the learning of these predictions and the inhibitory consequences that ensue, although less for a causal relationship between the two. In the context of a highly simplified model of chains of affectively charged thoughts, we interpret the combined effects of serotonin in terms of pruning a tree of possible decisions, (i.e., eliminating those choices that have low or negative expected outcomes). We show how a drop in behavioral inhibition, putatively resulting from an experimentally or psychiatrically influenced drop in serotonin, could result in unexpectedly large negative prediction errors and a significant aversive shift in reinforcement statistics. We suggest an interpretation of this finding that helps dissolve the apparent contradiction between the fact that inhibition of serotonin reuptake is the first-line treatment of depression, although serotonin itself is most strongly linked with aversive rather than appetitive outcomes and predictions. PMID:18248087

  19. Negative regulators of cell proliferation

    NASA Technical Reports Server (NTRS)

    Johnson, T. C.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    Cell proliferation is governed by the influence of both mitogens and inhibitors. Although cell contact has long been thought to play a fundamental role in cell cycling regulation, and negative regulators have long been suspected to exist, their isolation and purification has been complicated by a variety of technical difficulties. Nevertheless, over recent years an ever-expanding list of putative negative regulators have emerged. In many cases, their biological inhibitory activities are consistent with density-dependent growth inhibition. Most likely their interactions with mitogenic agents, at an intracellular level, are responsible for either mitotic arrest or continued cell cycling. A review of naturally occurring cell growth inhibitors is presented with an emphasis on those factors shown to be residents of the cell surface membrane. Particular attention is focused on a cell surface sialoglycopeptide, isolated from intact bovine cerebral cortex cells, which has been shown to inhibit the proliferation of an unusually wide range of target cells. The glycopeptide arrest cells obtained from diverse species, both fibroblasts and epithelial cells, and a broad variety of transformed cells. Signal transduction events and a limited spectrum of cells that are refractory to the sialoglycopeptide have provided insight into the molecular events mediated by this cell surface inhibitor.

  20. Dynamically variable negative stiffness structures.

    PubMed

    Churchill, Christopher B; Shahan, David W; Smith, Sloan P; Keefe, Andrew C; McKnight, Geoffrey P

    2016-02-01

    Variable stiffness structures that enable a wide range of efficient load-bearing and dexterous activity are ubiquitous in mammalian musculoskeletal systems but are rare in engineered systems because of their complexity, power, and cost. We present a new negative stiffness-based load-bearing structure with dynamically tunable stiffness. Negative stiffness, traditionally used to achieve novel response from passive structures, is a powerful tool to achieve dynamic stiffness changes when configured with an active component. Using relatively simple hardware and low-power, low-frequency actuation, we show an assembly capable of fast (<10 ms) and useful (>100×) dynamic stiffness control. This approach mitigates limitations of conventional tunable stiffness structures that exhibit either small (<30%) stiffness change, high friction, poor load/torque transmission at low stiffness, or high power active control at the frequencies of interest. We experimentally demonstrate actively tunable vibration isolation and stiffness tuning independent of supported loads, enhancing applications such as humanoid robotic limbs and lightweight adaptive vibration isolators.

  1. Negative nonlinear damping of a multilayer graphene mechanical resonator

    NASA Astrophysics Data System (ADS)

    Singh, Vibhor; Shevchuk, Olga; Blanter, Ya. M.; Steele, Gary A.

    2016-06-01

    We experimentally investigate the nonlinear response of a multilayer graphene resonator using a superconducting microwave cavity to detect its motion. The radiation pressure force is used to drive the mechanical resonator in an optomechanically induced transparency configuration. By varying the amplitudes of drive and probe tones, the mechanical resonator can be brought into a nonlinear limit. Using the calibration of the optomechanical coupling, we quantify the mechanical Duffing nonlinearity. By increasing the drive force, we observe a decrease in the mechanical dissipation rate at large amplitudes, suggesting a negative nonlinear damping mechanism in the graphene resonator. Increasing the optomechanical backaction further, we observe instabilities in the mechanical response.

  2. Some Phenomena on Negative Inversion Constructions

    ERIC Educational Resources Information Center

    Sung, Tae-Soo

    2013-01-01

    We examine the characteristics of NDI (negative degree inversion) and its relation with other inversion phenomena such as SVI (subject-verb inversion) and SAI (subject-auxiliary inversion). The negative element in the NDI construction may be" not," a negative adverbial, or a negative verb. In this respect, NDI has similar licensing…

  3. Radiation physics, biophysics, and radiation biology

    SciTech Connect

    Hall, E.J.; Zaider, M.

    1993-05-01

    Research at the Center for Radiological Research is a multidisciplenary blend of physics, chemistry and biology aimed at understanding the mechanisms involved in the health problems resulting from human exposure to ionizing radiations. The focus is increased on biochemistry and the application of the techniques of molecular biology to the problems of radiation biology. Research highlights of the program from the past year are described. A mathematical model describing the production of single-strand and double-strand breaks in DNA as a function radiation quality has been completed. For the first time Monte Carlo techniques have been used to obtain directly the spatial distribution of DNA moieties altered by radiation. This information was obtained by including the transport codes a realistic description of the electronic structure of DNA. We have investigated structure activity relationships for the potential oncogenicity of a new generation of bioreductive drugs that function as hypoxic cytotoxins. Experimental and theoretical investigation of the inverse dose rate effect, whereby medium LET radiations actually produce an c effect when the dose is protracted, is now at a point where the basic mechanisms are reasonably understood and the complex interplay between dose, dose rate and radiation quality which is necessary for the effect to be present can now be predicted at least in vitro. In terms of early radiobiological damage, a quantitative link has been established between basic energy deposition and locally multiply damaged sites, the radiochemical precursor of DNA double strand breaks; specifically, the spatial and energy deposition requirements necessary to form LMDs have been evaluated. For the first time, a mechanically understood biological fingerprint'' of high-LET radiation has been established. Specifically measurement of the ratio of inter-to intra-chromosomal aberrations produces a unique signature from alpha-particles or neutrons.

  4. Compression of a photoinjector electron bunch in the negative-mass undulator

    NASA Astrophysics Data System (ADS)

    Bandurkin, Ilya V.; Kurakin, Ilya S.; Savilov, Andrey V.

    2017-02-01

    The use of the "negative mass" regime provides stabilization of longitudinal size of dense photoinjector electron bunches moving through a long undulator. This allows one to increase significantly the power capabilities of a terahertz source based on coherent spontaneous emission from a short bunch. However, such type of emission is produced if the bunch length is comparable with the radiation wavelength. This work discusses the use of the negative mass regime to provide effective compression of dense bunches down to "terahertz" lengths.

  5. An overview of triple negative breast cancer for surgical oncologists.

    PubMed

    Sharma, Shiva; Barry, Mitchel; Gallagher, David J; Kell, Malcolm; Sacchini, Virgilio

    2015-09-01

    Triple negative breast cancers (TNBCs) represent a distinct subgroup of breast cancers with an immunohistochemical phenotype that is negative for oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER-2). The aim of this article is to provide a broad overview of recent developments in the diagnosis and management of TNBC for surgical oncologists. This overview discusses the subtypes of TNBC and the relationship between this type of breast cancer and the BRCA1 gene. In addition, the article explores recent advances in the treatment of TNBC from a surgical, radiation, and medical oncology point of view. Lastly, evolving therapeutic strategies that have potential to enhance outcomes for patients with TNBC are also discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Earth Radiation Measurement Science

    NASA Technical Reports Server (NTRS)

    Smith, G. Louis

    2000-01-01

    This document is the final report for NASA Grant NAG1-1959, 'Earth Radiation Measurement Science'. The purpose of this grant was to perform research in this area for the needs of the Clouds and Earth Radiant Energy System (CERES) project and for the Earth Radiation Budget Experiment (ERBE), which are bing conducted by the Radiation and Aerosols Branch of the Atmospheric Sciences Division of Langley Research Center. Earth Radiation Measurement Science investigates the processes by which measurements are converted into data products. Under this grant, research was to be conducted for five tasks: (1) Point Response Function Measurements; (2) Temporal Sampling of Outgoing Longwave Radiation; (3) Spatial Averaging of Radiation Budget Data; (4) CERES Data Validation and Applications; and (5) ScaRaB Data Validation and Application.

  7. The flying radiation case

    SciTech Connect

    Brownell, J.H.; Bowers, R.L.

    1997-04-01

    The Los Alamos foil implosion program has the goal of producing an intense, high-energy density x-ray source by converting the energy of a magnetically imploded plasma into radiation and material energy. One of the methods for converting the plasma energy into thermal energy and radiation and utilizing it for experiments is called the flying radiation case (FRC). In this paper the authors shall model the FRC and provide a physical description of the processes involved. An analytic model of a planar FRC in the hydrodynamic approximation is used to describe the assembly and shock heating of a central cushion by a conducting liner driver. The results are also used to benchmark a hydrodynamics code for modeling an FRC. They then use a radiation-hydrodynamics computational model to explore the effects of radiation production and transport when a gold plasma assembles on a CH cushion. Results are presented for the structure and evolution of the radiation hohlraum.

  8. Radiation exposure and pregnancy.

    PubMed

    Labant, Amy; Silva, Christina

    2014-01-01

    Radiological exposure from nuclear power reactor accidents, transportation of nuclear waste accidents, industrial accidents, or terrorist activity may be a remote possibility, but it could happen. Nurses must be prepared to evaluate and treat pregnant women and infants who have been exposed to radiation, and to have an understanding of the health consequences of a nuclear or radiological incident. Pregnant women and infants are a special group of patients who need consideration when exposed to radiation. Initial care requires thorough assessment and decisions regarding immediate care needs. Ongoing care is based on type and extent of radiation exposure. With accurate, comprehensive information and education, nurses will be better prepared to help mitigate the effects of radiation exposure to pregnant women and infants following a radiological incident. Information about radiation, health effects of prenatal radiation exposure, assessment, patient care, and treatment of pregnant women and infants are presented.

  9. RADIATION WAVE DETECTION

    DOEpatents

    Wouters, L.F.

    1960-08-30

    Radiation waves can be detected by simultaneously measuring radiation- wave intensities at a plurality of space-distributed points and producing therefrom a plot of the wave intensity as a function of time. To this end. a detector system is provided which includes a plurality of nuclear radiation intensity detectors spaced at equal radial increments of distance from a source of nuclear radiation. Means are provided to simultaneously sensitize the detectors at the instant a wave of radiation traverses their positions. the detectors producing electrical pulses indicative of wave intensity. The system further includes means for delaying the pulses from the detectors by amounts proportional to the distance of the detectors from the source to provide an indication of radiation-wave intensity as a function of time.

  10. The Role of Optical Radiations in Skin Cancer

    PubMed Central

    Palla, Marco; Di Trolio, Rossella; Mozzillo, Nicola; Ascierto, Paolo A.

    2013-01-01

    Purpose. Electromagnetic radiation with wavelength in the range 100 nm to 1 mm is known as optical radiation and includes ultraviolet radiation, the visible spectrum, and infrared radiation. The deleterious short- and long-term biological effects of ultraviolet radiation, including melanoma and other skin cancers, are well recognized. Infrared radiation may also have damaging biological effects. Methods. The objective of this review was to assess the literature over the last 15 years and to summarize correlations between exposure to optical radiation and the risk of melanoma and other cancers. Results. There is a clear correlation between exposure to UV radiation and the development of skin cancer. Most importantly, a strong association between artificial UV radiation exposure, for example, tanning devices, and the risk of melanoma and squamous cell carcinoma has been clearly demonstrated. There is no clear evidence that exposure to IR and laser radiation may increase the risk of skin cancer, although negative health effects have been observed. Conclusions. Preventative strategies that involve provision of public information highlighting the risks associated with exposure to sunlight remain important. In addition, precautionary measures that discourage exposure to tanning appliances are required, as is legislation to prevent their use during childhood. PMID:23710365

  11. Double Negative Materials (DNM), Phenomena and Applications

    DTIC Science & Technology

    2009-07-01

    Nanoparticles Formed by Pairs Of Concentric Double-Negative (DNG), Single-Negative ( SNG ) and/or Double-Positive (DPS) Metamaterial Layers.” J. Appl...material RRL Rapid Research Letters SHG second-harmonic generation SNG single-negative SSR split-ring resonator A-1 Appendix A. October 2008...Pairs of Concentric Double-Negative (DNG), Single-Negative ( SNG ), and/or Double-Positive (DPS) Metamaterial Layers.” J. Appl. Phys. 97, no. 9 (May

  12. The Negations of Conjunctions, Conditionals, and Disjunctions

    DTIC Science & Technology

    2014-06-03

    assertion is to negate it, and negation serves an important function in natural language (e.g., Horn, 2001) and in logic (e.g., Aristotle , 1984; Quine...As Aristotle argued (see De Interpretatione in Aristotle , 1984, Vol. 1), negations contradict the negated assertion, i.e., they reverse its truth...may be easier to under stand than the negation of the full assertion, but it is incorrect. As Aristotle argued (see De Interpretatione in Aristotle

  13. Intracranial interstitial radiation

    SciTech Connect

    Willis, D.; Rittenmeyer, H.; Hitchon, P.

    1986-06-01

    Primary malignant brain tumors are fatal, with 90% of patients having these tumors dying within two years following diagnosis. Cranial interstitial radiation therapy, a technique under investigation to control these tumors, involves implantation of radioactive iodine 125 seeds into the tumor bed by stereotaxic technique. The interstitial radiation technique, monitoring of radiation, and nursing care of patients are discussed. Case histories are presented, along with discussion of results attained using this therapy, and its future.

  14. Electromagnetic Radiation Analysis

    DTIC Science & Technology

    1978-04-10

    A methodology is given for determining whether electromagnetic radiation of sufficient strength to cause performance degradation to the test item...exists at the test item location. The results of an electromagnetic radiation effects test are used to identify the radio frequencies and electromagnetic ... radiation levels to which the test item is susceptible. Further, using a test bed, comparisons are made with the representative signal levels to

  15. RHOBOT: Radiation hardened robotics

    SciTech Connect

    Bennett, P.C.; Posey, L.D.

    1997-10-01

    A survey of robotic applications in radioactive environments has been conducted, and analysis of robotic system components and their response to the varying types and strengths of radiation has been completed. Two specific robotic systems for accident recovery and nuclear fuel movement have been analyzed in detail for radiation hardness. Finally, a general design approach for radiation-hardened robotics systems has been developed and is presented. This report completes this project which was funded under the Laboratory Directed Research and Development program.

  16. Radiation Countermeasures Symposium: Introduction

    DTIC Science & Technology

    2011-06-15

    SH-containing molecules) protected animals from acute radiation syndrome (ARS). Free radical scavengers • 1950s-1980s: US Army (WRAIR) advanced...applications for G-CSF (Neupogen®) in case of radiation incident • Neupogen® in Strategic National Stockpile UNI FORM ED SERVIC ESUNIV ERSI T Y of theHealth...success for any radiation countermeasure under Animal Rule: long-term survival? (Need to cure hematopoietic syndrome when assessing GI

  17. Radiation budget study

    NASA Astrophysics Data System (ADS)

    Hartmann, D. L.

    Scientific applications of satellite measurements of the radiative flux density at the top of the atmosphere are discussed in a general review and illustrated with diagrams, maps, and graphs. Topics examined include model development and verification, empirical studies of the global radiation budget, regional energy budgeting, interannual-variability studies, and seasonal and nonseasonal variations in ocean-land radiation budgets. The need for long-term homogeneous series of observations with good spatial and temporal resolution is stressed.

  18. Aerosol, radiation, and climate

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.

    1983-01-01

    Airborne, spaceborne, and ground-based measurements are used to study the radiative and climatic effects of aerosols. The data, which are modelled with a hierarchy of radiation and climate models, and their implications are summarized. Consideration is given to volcanic aerosols, polar stratospheric clouds, and the Arctic haze. It is shown that several types of aerosols (volcanic particles and the Arctic haze) cause significant alterations to the radiation budget of the regions where they are located.

  19. Radiation | Smokefree.gov

    Cancer.gov

    About half of all cancer patients get radiation therapy. This treatment can damage healthy cells, which can cause uncomfortable side effects. Use this action deck to get information on common symptoms that affect people going through radiation and learn how to manage them. The side effects of radiation may depend on the part of your body being treated. If you don’t see the symptom cards that describe what you are going through, try building your own deck.

  20. Entanglement negativity in the multiverse

    SciTech Connect

    Kanno, Sugumi; Soda, Jiro E-mail: jonathan.shock@uct.ac.za

    2015-03-01

    We explore quantum entanglement between two causally disconnected regions in the multiverse. We first consider a free massive scalar field, and compute the entanglement negativity between two causally separated open charts in de Sitter space. The qualitative feature of it turns out to be in agreement with that of the entanglement entropy. We then introduce two observers who determine the entanglement between two causally disconnected de Sitter spaces. When one of the observers remains constrained to a region of the open chart in a de Sitter space, we find that the scale dependence enters into the entanglement. We show that a state which is initially maximally entangled becomes more entangled or less entangled on large scales depending on the mass of the scalar field and recovers the initial entanglement in the small scale limit. We argue that quantum entanglement may provide some evidence for the existence of the multiverse.

  1. Entanglement negativity in the multiverse

    SciTech Connect

    Kanno, Sugumi; Shock, Jonathan P.; Soda, Jiro

    2015-03-10

    We explore quantum entanglement between two causally disconnected regions in the multiverse. We first consider a free massive scalar field, and compute the entanglement negativity between two causally separated open charts in de Sitter space. The qualitative feature of it turns out to be in agreement with that of the entanglement entropy. We then introduce two observers who determine the entanglement between two causally disconnected de Sitter spaces. When one of the observers remains constrained to a region of the open chart in a de Sitter space, we find that the scale dependence enters into the entanglement. We show that a state which is initially maximally entangled becomes more entangled or less entangled on large scales depending on the mass of the scalar field and recovers the initial entanglement in the small scale limit. We argue that quantum entanglement may provide some evidence for the existence of the multiverse.

  2. Potential theory of radiation

    NASA Technical Reports Server (NTRS)

    Chiu, Huei-Huang

    1989-01-01

    A theoretical method is being developed by which the structure of a radiation field can be predicted by a radiation potential theory, similar to a classical potential theory. The introduction of a scalar potential is justified on the grounds that the spectral intensity vector is irrotational. The vector is also solenoidal in the limits of a radiation field in complete radiative equilibrium or in a vacuum. This method provides an exact, elliptic type equation that will upgrade the accuracy and the efficiency of the current CFD programs required for the prediction of radiation and flow fields. A number of interesting results emerge from the present study. First, a steady state radiation field exhibits an optically modulated inverse square law distribution character. Secondly, the unsteady radiation field is structured with two conjugate scalar potentials. Each is governed by a Klein-Gordon equation with a frictional force and a restoring force. This steady potential field structure and the propagation of radiation potentials are consistent with the well known results of classical electromagnetic theory. The extension of the radiation potential theory for spray combustion and hypersonic flow is also recommended.

  3. Living with radiation

    SciTech Connect

    Wagner, H.N. Jr. . Div. of Nuclear Medicine); Ketchum, L.E. )

    1989-01-01

    The authors present an account of the hopes and fears associated with ionizing radiation, extending from nuclear energy and medical radiation to nuclear weapons. They argue that a justified fear of nuclear weapons has led to a widespread, unjustified, and unreasoning fear of the beneficial applications of radiation. Although these two aspects of atomic energy are tied together-they both involve the nucleus of the atom and its radioactive rays-a deep misunderstanding of this relationship by the general public has evolved since the time of the atomic bombing of Hiroshima and Nagasaki. The authors' aim is to place the beneficial applications of nuclear radiation in perspective.

  4. Rotating bubble membrane radiator

    DOEpatents

    Webb, Brent J.; Coomes, Edmund P.

    1988-12-06

    A heat radiator useful for expelling waste heat from a power generating system aboard a space vehicle is disclosed. Liquid to be cooled is passed to the interior of a rotating bubble membrane radiator, where it is sprayed into the interior of the bubble. Liquid impacting upon the interior surface of the bubble is cooled and the heat radiated from the outer surface of the membrane. Cooled liquid is collected by the action of centrifical force about the equator of the rotating membrane and returned to the power system. Details regarding a complete space power system employing the radiator are given.

  5. Solar radiation concentrator

    SciTech Connect

    Gravisse, P.

    1982-04-13

    A luminescent solar radiation concentrator is disclosed. Incident radiation of flux phi 1, and wavelength lambda 1, impinges enclosure wall v1 having a double index of refraction n1, n2 (Where n2>n1) and then is absorbed by cascade fluorescent concentrator/converter cl, which isotropically re-emits fluorescent radiation at wavelength lambda 2 and flux phi 2 (Where lambda 2> lambda 1, and phi 2> phi 1) which then is absorbed by a solar photovoltaic cell. The double index of refraction wall prevents escape of fluorescence radiation from the enclosure.

  6. Flexible radiator system

    NASA Technical Reports Server (NTRS)

    Oren, J. A.

    1982-01-01

    The soft tube radiator subsystem is described including applicable system requirements, the design and limitations of the subsystem components, and the panel manufacturing method. The soft tube radiator subsystem is applicable to payloads requiring 1 to 12 kW of heat rejection for orbital lifetimes per mission of 30 days or less. The flexible radiator stowage volume required is about 60% and the system weight is about 40% of an equivalent heat rejection rigid panel. The cost should also be considerably less. The flexible radiator is particularly suited to shuttle orbiter sortie payloads and also whose mission lengths do not exceed the 30 day design life.

  7. [Thyroid and radiation].

    PubMed

    Yamashita, S; Namba, H; Nagataki, S

    1993-11-20

    The topic "Thyroid and Radiation" is both an old and a new area to be solved by human beings. The thyroid is an organ that is usually susceptible to exposure to ionizing radiation, both by virtue of its ability to concentrate radioiodine (internal radiation) and by routine medical examination: Chest X-ray, Dental X-ray, X-irradiation of cervical lymphnodes etc. (external radiation). Iodine-131 is widely used for the therapy of Graves' disease and thyroid cancers, of which the disadvantage is radiation-induced hypothyroidism but not complications of thyroid tumor. The thyroid gland is comparatively radioresistant, however, the data obtained from Hiroshima, Nagasaki and Marshall islands indicates a high incidence of external radiation-induced thyroid tumors as well as hypothyroidism. The different biological effects of internal and external radiation remains to be further clarified. Interestingly, recent reports demonstrate the increased number of thyroid cancer in children around Chernobyl in Belarus. In this review, we would like to introduce the effect of radiation on the thyroid gland at the molecular, cellular and tissue levels. Furthermore the clinical usefulness of iodine-131, including the safety-control for radiation exposure will be discussed.

  8. Charms of radiation research.

    SciTech Connect

    Inokuti, M.; Physics

    2005-01-01

    Most of my professional efforts over nearly five decades have been devoted to radiation research, that is, studies of the physical, chemical, and biological actions of high-energy radiation on matter. (By the term 'high-energy radiation' I mean here x rays, .GAMMA. rays, neutrons, and charged particles of high enough energies to produce ionization in matter. I exclude visible light, infrared waves, microwaves, and sound waves.) Charms of radiation research lie in its interdisciplinary character; although my training was in basic physics, the scope of my interest has gradually increased to cover many other areas, to my deep satisfaction. High-energy radiation is an important component of the universe, and of our environment. It often provides an effective avenue for characterizing matter and understanding its behavior. Near Earth's surface this radiation is normally present in exceptionally low quantity, and yet it plays a significant role in some atmospheric phenomena such as auroras, and also in the evolution of life. The recent advent of various devices for producing high-energy radiation has opened up the possibility of many applications, including medical and industrial uses. I have worked on some aspects of those uses. At every opportunity to address a broad audience I try to convey a sense of intellectual fun, together with some of the elements of the basic science involved. A goal of radiation education might be to make the word 'radiation' as common and familiar as words such as 'fire' and 'electricity' through increased usage.

  9. Radiation coloration resistant glass

    DOEpatents

    Tomozawa, M.; Watson, E.B.; Acocella, J.

    1986-11-04

    A radiation coloration resistant glass is disclosed which is used in a radiation environment sufficient to cause coloration in most forms of glass. The coloration resistant glass includes higher proportions by weight of water and has been found to be extremely resistant to color change when exposed to such radiation levels. The coloration resistant glass is free of cerium oxide and has more than about 0.5% by weight water content. Even when exposed to gamma radiation of more than 10[sup 7] rad, the coloration resistant glass does not lose transparency. 3 figs.

  10. Radiation coloration resistant glass

    DOEpatents

    Tomozawa, Minoru; Watson, E. Bruce; Acocella, John

    1986-01-01

    A radiation coloration resistant glass is disclosed which is used in a radiation environment sufficient to cause coloration in most forms of glass. The coloration resistant glass includes higher proportions by weight of water and has been found to be extremely resistant to color change when exposed to such radiation levels. The coloration resistant glass is free of cerium oxide and has more than about 0.5% by weight water content. Even when exposed to gamma radiation of more than 10.sup.7 rad, the coloration resistant glass does not lose transparency.

  11. Radiation physics, biophysics, and radiation biology

    SciTech Connect

    Hall, E.J.

    1992-05-01

    The following research programs from the Center for Radiological Research of Columbia University are described: Design and development of a new wall-less ultra miniature proportional counter for nanodosimetry; some recent measurements of ionization distributions for heavy ions at nanometer site sizes with a wall-less proportional counter; a calculation of exciton energies in periodic systems with helical symmetry: application to a hydrogen fluoride chain; electron energy-loss function in polynucleotide and the question of plasmon excitation; a non-parametric, microdosimetric-based approach to the evaluation of the biological effects of low doses of ionizing radiation; high-LET radiation risk assessment at medium doses; high-LET radiobiological effects: increased lesion severity or increased lesion proximity; photoneutrons generated by high energy medical linacs; the biological effectiveness of neutrons; implications for radiation protection; molecular characterization of oncogenes induced by neutrons; and the inverse dose-rate effect for oncogenic transformation by charged particles is LET dependent.

  12. Cosmology with Negative Potentials with wϕ<-1

    NASA Astrophysics Data System (ADS)

    de La Macorra, A.; Germán, G.

    We study the cosmology of canonically normalized scalar fields that lead to an equation of state parameter of wϕ=pϕ/ρϕ<-1 without violating the weak energy condition: ρ=Σiρi≥0 and ρi+pi≥0. This kind of behavior requires a negative scalar potential V, widely predicted in particle physics. We show that the energy density ρϕ=Ek+V takes negative values with an equation of state with wϕ<-1. However, the net effect of the ϕ field on the scale factor is to decelerate it giving a total equation of state parameter w=p/ρ>wb=pb/ρb, where ρb stands for any kind of energy density with -1≤wb≤1, such as radiation, matter, cosmological constant or other scalar field with a potential V≥0. The fact that ρϕ<0 allows, at least in principle, to have a small cosmological constant or quintessence today as the cancellation of high energy scales such as the electroweak or susy breaking scale. While V is negative |ρϕ| is smaller than the sum of all other energy densities regardless of the functional form of the potential V. We show that the existence of a negative potential leads, inevitable, to a collapsing universe, i.e. to a would be "big crunch." In this picture we would still be living in the expanding universe.

  13. Ionizing radiation and mitogenetic radiation: two links of the same energetic chain in a biological cell.

    PubMed

    Goraczko, W

    2000-03-01

    Present research demonstrates that the excitation of living systems by high energy/low doses of ionizing radiation (IR) initiates prolonged secondary ultraviolet (UV) range emission that influences biota. When doses of this energy are too high, the process of energy or radiation absorption by the cells causes negative changes (i.e. negative mutations or death). When these doses are sufficiently low, vital processes inside the cells are stimulated and can create positive changes. This paper proposes a common denomination for mechanisms of UV and ionizing radiation when interacting with living cells, underlying both its mitogenetic effect and radiation hormesis. Data from radon exposure in chronically exposed nuclear workers, acutely exposed Hiroshima and Nagasaki victims and observers of atmospheric nuclear explosions, combined with animal results, present irrefutable evidence that low doses of IR are beneficial. As a conclusion the author postulates the possibility of new methods of therapy regarding the use of IR and mitogenetic radiation. This paper has been written to encourage debate regarding possible future benefits that may be derived from low level doses of IR exposure in the general population.

  14. Melioidosis: reactivation during radiation therapy

    SciTech Connect

    Jegasothy, B.V.; Goslen, J.B.; Salvatore, M.A.

    1980-05-01

    Melioidosis is caused by Pseudomonas pseudomallei, a gram-negative, motile bacillus which is a naturally occurring soil saprophyte. The organism is endemic in Southeast Asia, the Philippines, Australia, and parts of Central and South America. Most human disease occurs from infection acquired in these countries. Infection with P pseudomallei may produce no apparent clinical disease. Acute pneumonitis or septicemia may result from inhalation of the organism, and inoculation into sites of trauma may cause localized skin abscesses, or the disease may remain latent and be reactivated months or years later by trauma, burns, or pneumococcal pneumonia, diabetic ketoacidosis, influenza, or bronchogenic carcinoma. The last is probably the commonest form of melioidosis seen in the United States. We present the first case of reactivation of melioidosis after radiation therapy for carcinoma of the lung, again emphasizing the need to consider melioidosis in a septic patient with a history of travel, especially to Southeast Asia.

  15. Negative refraction in anisotropic composites

    NASA Astrophysics Data System (ADS)

    Chui, S. T.

    2004-03-01

    Left-handed materials (LHM) are materials in which the direction of wave propagation S is opposite to the wave vector k . S <0 .[1,2,3] LHM exhibit nagative refraction. Experiments have been carried out on a medium consisting of arrays of metallic rings and wrires.[3] An example of a different class of anisotropic left-handed materials are metallic magnetic granular composites. Based on the effective medium approximation, we show that by incorporating metallic magnetic nanoparticles into an appropriate insulating matrix, it may be possible to prepare a composite medium of low eddy current loss which is left-handed for electromagnetic waves propagating in some special direction and polarization in a frequency region near the ferromagnetic resonance frequency.[4,5] This composite may be easier to make on an industrial scale. In addition, its physical properties may be easily tuned by rotating the magnetization locally. The physics involved seems to be different from the original argument.[1,2] In our argument[5], the imaginary part of the dielectric constant of the metal is much larger than the real part, opposite to the original argument. In anisotropic materials so that some of the susceptibilities are negative, the criterion for LHM may not be the same as that for negative refraction.[6] Ansiotropic materials exhibit a richer manifold of anomlous behaviour[6,7,8] and offers more flexibility in apllications.[8] More recently it was found that negative refraction can occur in anisotropic materials where all the susceptibilities are positive.[9] We found that the range of applicability of this effect is much larger than originally thought.[10] S. T. Chui was supported in part by the Office of Naval Research, by the Army Research Laboratory through the Center of Composite Materials at the University of Delaware, by DARPA and by the NSF. [1] J.B.Pendry, A.J.Holden, W.J.Stewart, and I.Youngs, Phys. Rev. Lett 76, 4773 (1996). [2] V.G.Veselago, Sov. Phys. Usp. 10, 509

  16. Negative Numbers and Antimatter Particles

    NASA Astrophysics Data System (ADS)

    Tsan, Ung Chan

    Dirac's equation states that an electron implies the existence of an antielectron with the same mass (more generally same arithmetic properties) and opposite charge (more generally opposite algebraic properties). Subsequent observation of antielectron validated this concept. This statement can be extended to all matter particles; observation of antiproton, antineutron, antideuton … is in complete agreement with this view. Recently antihypertriton was observed and 38 atoms of antihydrogen were trapped. This opens the path for use in precise testing of nature's fundamental symmetries. The symmetric properties of a matter particle and its mirror antimatter particle seem to be well established. Interactions operate on matter particles and antimatter particles as well. Conservation of matter parallels addition operating on positive and negative numbers. Without antimatter particles, interactions of the Standard Model (electromagnetism, strong interaction and weak interaction) cannot have the structure of group. Antimatter particles are characterized by negative baryonic number A or/and negative leptonic number L. Materialization and annihilation obey conservation of A and L (associated to all known interactions), explaining why from pure energy (A = 0, L = 0) one can only obtain a pair of matter particle antimatter particle — electron antielectron, proton and antiproton — via materialization where the mass of a pair of particle antiparticle gives back to pure energy with annihilation. These two mechanisms cannot change the difference in the number of matter particles and antimatter particles. Thus from pure energy only a perfectly symmetric (in number) universe could be generated as proposed by Dirac but observation showed that our universe is not symmetric, it is a matter universe which is nevertheless neutral. Fall of reflection symmetries shattered the prejudice that there is no way to define in an absolute way right and left or matter and antimatter

  17. Negative pressure wound therapy in head and neck surgery.

    PubMed

    Asher, Scott A; White, Hilliary N; Golden, Joseph B; Magnuson, J Scott; Carroll, William R; Rosenthal, Eben L

    2014-01-01

    IMPORTANCE Negative pressure wound therapy has been shown to accelerate healing. There is a paucity of literature reporting its use as a tool to promote wound healing in head and neck reconstruction. OBJECTIVE To review 1 institution's experience with negative pressure dressings to further describe the indications, safety, and efficacy of this technique in the head and neck. DESIGN, SETTING, AND PARTICIPANTS Retrospective case series at a tertiary care academic hospital. One hundred fifteen patients had negative pressure dressings applied between April 2005 and December 2011. Data were gathered, including indications, details of negative pressure dressing use, adverse events, wound healing results, potential risk factors for compromised wound healing (defined as previous radiation therapy, hypothyroidism, or diabetes mellitus), and wound characteristics (complex wounds included those with salivary contamination, bone exposure, great vessel exposure, in the field of previous microvascular free tissue transfer, or in the case of peristomal application in laryngectomy). EXPOSURE Negative pressure wound therapy utilized after head and neck reconstruction. MAIN OUTCOMES AND MEASURES Indications for therapy, length and number of dressing applications, identification of wound healing risk factors, classification of wound complexity, wound healing results, and adverse events related to the use of the device. RESULTS Negative pressure wound therapy was used primarily for wounds of the neck (94 of 115 patients [81.7%]) in addition to other head and neck locations (14 of 115 patients [12.2%]), and free tissue transfer donor sites (7 of 115 patients [6.1%]). The mean (SD) wound size was 5.6 (5.0) cm. The mean number of negative pressure dressing applications was 1.7 (1.2), with an application length of 3.7 (1.4) days. Potential risk factors for compromised wound healing were present in 82 of 115 patients (71.3%). Ninety-one of 115 patients (79.1%) had complex wounds. Negative

  18. Radiation therapy for intrahepatic malignancies.

    PubMed

    Quick, Allison M; Lo, Simon S; Mayr, Nina A; Kim, Edward Y

    2009-10-01

    Historically, radiation was not used in the management of hepatocellular carcinoma and liver metastasis because of the low tolerance of the liver to radiation. More recently, improvements in radiation delivery using advanced techniques, such as 3D conformal radiation therapy, intensity-modulated radiation therapy, image-guided radiation therapy, stereotactic body radiation therapy, proton-beam therapy and internal radiation therapy, have enabled partial and selective irradiation of the liver with promising response rates and toxicity profiles. This review will discuss the different techniques of radiation that can now be used to treat intrahepatic malignancies and the important clinical studies in the medical literature.

  19. Negative Plasma Densities Raise Questions

    SciTech Connect

    Hazi, A

    2006-01-26

    Nearly all the matter encountered on Earth is either a solid, liquid, or gas. Yet plasma-the fourth state of matter-comprises more than 99 percent of the visible universe. Understanding the physical characteristics of plasmas is important to many areas of scientific research, such as the development of fusion as a clean, renewable energy source. Lawrence Livermore scientists study the physics of plasmas in their pursuit to create fusion energy, because plasmas are an integral part of that process. When deuterium and tritium are heated to the extreme temperatures needed to achieve and sustain a fusion reaction (about 100 million degrees), the electrons in these light atoms become separated from the nuclei. This process of separation is called ionization, and the resulting collection of negatively charged free electrons and positively charged nuclei is known as a plasma. Although plasmas and gases have many similar properties, plasmas differ from gases in that they are good conductors of electricity and can generate magnetic fields. For the past decade, x-ray laser interferometry has been used in the laboratory for measuring a plasma's index of refraction to determine plasma density. (The index of refraction for a given material is defined as the wavelength of light in a vacuum divided by the wavelength of light traveling through the material.) Until now, plasma physicists expected to find an index of refraction less than one. Researchers from Livermore and Colorado State University recently conducted experiments on aluminum plasmas at the Laboratory's COMET laser facility and observed results in which the index of refraction was greater than one. This surprising result implied a negative electron density. Livermore physicist Joseph Nilsen and his colleagues from Livermore and the University of Notre Dame have performed sophisticated calculations to explain this phenomenon. Previously, researchers believed that only free electrons contributed to the index of

  20. Quantum radiation from a sandwich black hole

    NASA Astrophysics Data System (ADS)

    Frolov, Valeri P.; Zelnikov, Andrei

    2017-02-01

    We discuss quantum radiation of a massless scalar field from a spherically symmetric nonsingular black hole with a finite lifetime. Namely, we discuss a sandwich black-hole model, where a black hole is originally created by a collapse of a null shell of mass M , and later, after some time Δ V , it is disrupted by the collapse of the other shell with negative mass -M . We assume that between the shells the metric is static and either coincides with the Hayward metric or with a special generalization of it. We show that in both cases for a sufficiently large parameter Δ V the radiation after the formation of the black hole practically coincides with the Hawking result. We also calculate the radiation, emitted from the black hole interior. This radiation contains a peak at the moment when the second shell intersects the inner horizon. In the standard sandwich metric (with the Hayward interior) this outburst of energy is exponentially large. In the modified metric, which includes an additional nontrivial redshift parameter, this exponent is suppressed. This is a result of a significant decrease of the surface gravity of the inner horizon in the latter case. We discuss possible consequences of this result in the context of the self-consistency requirement for nonsingular models with quantum radiation.

  1. Acoustic emission sensor radiation damage threshold experiment

    SciTech Connect

    Beeson, K.M.; Pepper, C.E.

    1994-09-01

    Determination of the threshold for damage to acoustic emission sensors exposed to radiation is important in their application to leak detection in radioactive waste transport and storage. Proper response to system leaks is necessary to ensure the safe operation of these systems. A radiation impaired sensor could provide ``false negative or false positive`` indication of acoustic signals from leaks within the system. Research was carried out in the Radiochemical Technology Division at Oak Ridge National Laboratory to determine the beta/gamma radiation damage threshold for acoustic emission sensor systems. The individual system consisted of an acoustic sensor mounted with a two part epoxy onto a stainless steel waveguide. The systems were placed in an irradiation fixture and exposed to a Cobalt-60 source. After each irradiation, the sensors were recalibrated by Physical Acoustics Corporation. The results were compared to the initial calibrations performed prior to irradiation and a control group, not exposed to radiation, was used to validate the results. This experiment determines the radiation damage threshold of each acoustic sensor system and verifies its life expectancy, usefulness and reliability for many applications in radioactive environments.

  2. Radiation sterilization of skin allograft

    NASA Astrophysics Data System (ADS)

    Kairiyama, E.; Horak, C.; Spinosa, M.; Pachado, J.; Schwint, O.

    2009-07-01

    In the treatment of burns or accidental loss of skin, cadaveric skin allografts provide an alternative to temporarily cover a wounded area. The skin bank facility is indispensable for burn care. The first human skin bank was established in Argentina in 1989; later, 3 more banks were established. A careful donor selection is carried out according to the national regulation in order to prevent transmissible diseases. As cadaveric human skin is naturally highly contaminated, a final sterilization is necessary to reach a sterility assurance level (SAL) of 10 -6. The sterilization dose for 106 batches of processed human skin was determined on the basis of the Code of Practice for the Radiation Sterilization of Tissue Allografts: Requirements for Validation and Routine Control (2004) and ISO 11137-2 (2006). They ranged from 17.6 to 33.4 kGy for bioburdens of >10-162.700 CFU/100 cm 2. The presence of Gram negative bacteria was checked for each produced batch. From the analysis of the experimental results, it was observed that the bioburden range was very wide and consequently the estimated sterilization doses too. If this is the case, the determination of a tissue-specific dose per production batch is necessary to achieve a specified requirement of SAL. Otherwise if the dose of 25 kGy is preselected, a standardized method for substantiation of this dose should be done to confirm the radiation sterilization process.

  3. Space Radiation Transport Methods Development

    NASA Astrophysics Data System (ADS)

    Wilson, J.; Tripathi, R.; Qualls, G.; Cucinotta, F.; Prael, R.; Norbury, J.

    Early space radiation shield code development relied on Monte Carlo methods for proton, neutron and pion transport and made important contributions to the space program. More recently Monte Carlo code LAHET has been upgraded to include high-energy multiple-charged light ions for GCR simulations and continues to be expanded in capability. To compensate for low computational efficiency, Monte Carlo methods have resorted to restricted one-dimensional problems leading to imperfect representations of appropriate boundary conditions. Even so, intensive computational requirements resulted and shield evaluation was made near the end of the design process and resolving shielding issues usually had a negative impact on the design. We evaluate the implications of these common one-dimensional assumptions on the evaluation of the Shuttle internal radiation field. Improved spacecraft shield design requires early entry of radiation constraints into the design process to maximize performance and minimize costs. As a result, we have been investigating high-speed computational procedures to allow shield analysis from the preliminary design concepts to the final design. In particular, we will discuss the progress towards a full three-dimensional and computationally efficient deterministic code for which the current HZETRN evaluates the lowest order asymptotic term. HZETRN is the first deterministic solution to the Boltzmann equation allowing field mapping within the International Space Station (ISS) in tens of minutes using standard Finite Element Method (FEM) geometry common to engineering design practice enabling development of integrated multidisciplinary design optimization methods. A single ray trace in ISS FEM geometry requires 14 milliseconds and severely limits application of Monte Carlo methods to such engineering models. A potential means of improving the Monte Carlo efficiency in coupling to spacecraft geometry is given in terms of reconfigurable computing and could be

  4. Radiation-induced moyamoya syndrome

    SciTech Connect

    Desai, Snehal S.; Paulino, Arnold C. . E-mail: apaulino@tmh.tmc.edu; Mai, Wei Y.; Teh, Bin S.

    2006-07-15

    Purpose: The moyamoya syndrome is an uncommon late complication after radiotherapy (RT). Methods and Materials: A PubMed search of English-language articles, with radiation, radiotherapy, and moyamoya syndrome used as search key words, yielded 33 articles from 1967 to 2002. Results: The series included 54 patients with a median age at initial RT of 3.8 years (range, 0.4 to 47). Age at RT was less than 5 years in 56.3%, 5 to 10 years in 22.9%, 11 to 20 years in 8.3%, 21 to 30 years in 6.3%, 31 to 40 years in 2.1%, and 41 to 50 years in 4.2%. Fourteen of 54 patients (25.9%) were diagnosed with neurofibromatosis type 1 (NF-1). The most common tumor treated with RT was low-grade glioma in 37 tumors (68.5%) of which 29 were optic-pathway glioma. The average RT dose was 46.5 Gy (range, 22-120 Gy). For NF-1-positive patients, the average RT dose was 46.5 Gy, and for NF-1-negative patients, it was 58.1 Gy. The median latent period for development of moyamoya syndrome was 40 months after RT (range, 4-240). Radiation-induced moyamoya syndrome occurred in 27.7% of patients by 2 years, 53.2% of patients by 4 years, 74.5% of patients by 6 years, and 95.7% of patients by 12 years after RT. Conclusions: Patients who received RT to the parasellar region at a young age (<5 years) are the most susceptible to moyamoya syndrome. The incidence for moyamoya syndrome continues to increase with time, with half of cases occurring within 4 years of RT and 95% of cases occurring within 12 years. Patients with NF-1 have a lower radiation-dose threshold for development of moyamoya syndrome.

  5. Synchrotron Radiation II.

    ERIC Educational Resources Information Center

    MOSAIC, 1978

    1978-01-01

    Synchrotron radiation is a unique form of radiation that spans the electro-magnetic spectrum from X-rays through the ultraviolet and visible into the infrared. Tunable monochromators enable scientists to select a narrow band of wavelengths at any point in the spectrum. (Author/BB)

  6. Radiation in the universe

    NASA Technical Reports Server (NTRS)

    Stuhlinger, Ernst; Truemper, Joachim; Weisskopf, Martin

    1992-01-01

    When Wilhelm Conrad Roentgen discovered radiation one hundred years ago, it seemed that what was discovered was one of the rarest and most volatile members of the family of the basic modules of our natural world. Today cosmologists report that a substantial part of the universe's radiation energy consists of X-rays, which travel through cosmic space with the speed of light.

  7. Treatment of Radiation Injury

    PubMed Central

    Akita, Sadanori

    2014-01-01

    Significance: Radiation exposure as a result of radiation treatment, accident, or terrorism may cause serious problems such as deficiency due to necrosis or loss of function, fibrosis, or intractable ulcers in the tissues and organs. When the skin, bone, oral mucous membrane, guts, or salivary glands are damaged by ionizing radiation, the management and treatment are very lengthy and difficult. Critical Issues: In severe and irreversible injuries, surgery remains the mainstay of treatment. Several surgical procedures, such as debridement, skin grafting, and local and free-vascularized flaps, are widely used. Recent Advances: In specific cases of major morbidity or in high-risk patients, a newly developed therapy using a patient's own stem cells is safe and effective. Adipose tissue, normally a rich source of mesenchymal stem cells, which are similar to those from the bone marrow, can be harvested, since the procedure is easy, and abundant tissue can be obtained with minimal invasiveness. Future Directions: Based on the molecular basis of radiation injuries, several prospective treatments are under development. Single-nucleotide polymorphisms focus on an individual's sensitivity to radiation in radiogenomics, and the pathology of radiation fibrosis or the effect of radiation on wound healing is being studied and will lead to new insight into the treatment of radiation injuries. Protectors and mitigators are being actively investigated in terms of the timing of administration or dose. PMID:24761339

  8. Microcircuit radiation effects databank

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Radiation test data submitted by many testers is collated to serve as a reference for engineers who are concerned with and have some knowledge of the effects of the natural radiation environment on microcircuits. Total dose damage information and single event upset cross sections, i.e., the probability of a soft error (bit flip) or of a hard error (latchup) are presented.

  9. Radiation-induced pneumothorax

    SciTech Connect

    Epstein, D.M.; Littman, P.; Gefter, W.B.; Miller, W.T.; Raney, R.B. Jr.

    1983-01-01

    Pneumothorax is an uncommon complication of radiation therapy to the chest. The proposed pathogenesis is radiation-induced fibrosis promoting subpleural bleb formation that ruptures resulting in pneumothorax. We report on two young patients with primary sarcomas without pulmonary metastases who developed spontaneous pneumothorax after irradiation. Neither patient had antecedent radiographic evidence of pulmonary fibrosis.

  10. Synchrotron Radiation II.

    ERIC Educational Resources Information Center

    MOSAIC, 1978

    1978-01-01

    Synchrotron radiation is a unique form of radiation that spans the electro-magnetic spectrum from X-rays through the ultraviolet and visible into the infrared. Tunable monochromators enable scientists to select a narrow band of wavelengths at any point in the spectrum. (Author/BB)

  11. Radiation: Doses, Effects, Risks.

    ERIC Educational Resources Information Center

    Lean, Geoffrey, Ed.

    Few scientific issues arouse as much public controversy as the effects of radiation. This booklet is an attempt to summarize what is known about radiation and provide a basis for further discussion and debate. The first four chapters of the booklet are based on the most recent reports to the United Nations' General Assembly by the United Nations…

  12. Instrument for assaying radiation

    DOEpatents

    Coleman, Jody Rustyn; Farfan, Eduardo B.

    2016-03-22

    An instrument for assaying radiation includes a flat panel detector having a first side opposed to a second side. A collimated aperture covers at least a portion of the first side of the flat panel detector. At least one of a display screen or a radiation shield may cover at least a portion of the second side of the flat panel detector.

  13. Ultraviolet radiation changes

    NASA Technical Reports Server (NTRS)

    Mckenzie, Richard L.; Frederick, John E.; Ilyas, Mohammad; Filyushkin, V.; Wahner, Andreas; Stamnes, K.; Muthusubramanian, P.; Blumthaler, M.; Roy, Colin E.; Madronich, Sasha

    1991-01-01

    A major consequence of ozone depletion is an increase in solar ultraviolet (UV) radiation received at the Earth's surface. This chapter discusses advances that were made since the previous assessment (World Meteorological Organization (WMO)) to our understanding of UV radiation. The impacts of these changes in UV on the biosphere are not included, because they are discussed in the effects assessment.

  14. Radiation-resistant microorganism

    DOEpatents

    Fliermans, Carl B.

    2010-06-15

    An isolated and purified bacterium is provided which was isolated from a high-level radioactive waste site of mixed waste. The isolate has the ability to degrade a wide variety of organic contaminants while demonstrating high tolerance to ionizing radiation. The organism is uniquely suited to bioremediation of a variety or organic contaminants while in the presence of ionizing radiation.

  15. Radiation-resistant microorganism

    DOEpatents

    Fliermans, Carl B.

    2007-01-09

    An isolated and purified bacterium is provided which was isolated from a high-level radioactive waste site of mixed waste. The isolate has the ability to degrade a wide variety of organic contaminants while demonstrating high tolerance to ionizing radiation. The organism is uniquely suited to bioremediation of a variety or organic contaminants while in the presence of ionizing radiation.

  16. Radiation-induced disease.

    PubMed

    Bobrow, M

    1993-01-01

    The term radiation covers a wide spectrum of forms of energy, most of which have at one stage or another been suspected of causing human ill health. In general, study of the effects of radiation on health involves a mix of scientific disciplines, from population epidemiology to physics, which are seldom if ever found in a single scientist. As a result, interdisciplinary communication is of the utmost importance, and is a potent source of misunderstanding and misinformation. The forms of radiation which have been most specifically associated with health effects include ionizing and ultraviolet radiation. Claimed effects of electromagnetic and microwave radiation (excluding thermal effects) are too indefinite for detailed consideration. Ionizing radiation is a well-documented mutagen, which clearly causes cancers in humans, and human exposure has been increased by atomic weapons testing and medical and industrial uses of radioactivity. There is also a growing awareness of the possible role of some types of natural radiation, such as radon, in causing disease. Ultraviolet radiation is also associated with cancers, and is suspected of involvement in the increasing incidence of skin cancers in European populations. Factors thought to underlie recent changes in exposure to these mutagens are discussed.

  17. Radiation treatment of pharmaceuticals

    NASA Astrophysics Data System (ADS)

    Dám, A. M.; Gazsó, L. G.; Kaewpila, S.; Maschek, I.

    1996-03-01

    Product specific doses were calculated for pharmaceuticals to be radiation treated. Radio-pasteurization dose were determined for some heat sensitive pharmaceutical basic materials (pancreaton, neopancreatin, neopancreatin USP, duodenum extract). Using the new recommendation (ISO standards, Method 1) dose calculations were performed and radiation sterilization doses were determined for aprotinine and heparine Na.

  18. Radiation effects in space

    SciTech Connect

    Fry, R.J.M.

    1987-07-01

    As more people spend more time in space, and the return to the moon and exploratory missions are considered, the risks require continuing examination. The effects of microgravity and radiation are two potential risks in space. These risks increase with increasing mission duration. This document considers the risk of radiation effects in space workers and explorers. 17 refs., 1 fig., 4 tabs.

  19. On Blackbody Radiation.

    ERIC Educational Resources Information Center

    Jain, Pushpendra K.

    1991-01-01

    The interrelationship between the various forms of the Planck radiation equation is discussed. A differential equation that gives intensity or energy density of radiation per unit wavelength or per unit frequency is emphasized. The Stefan-Boltzmann Law and the change in the glow of a hot body with temperature are also discussed. (KR)

  20. Radiation belts of jupiter.

    PubMed

    Stansberry, K G; White, R S

    1973-12-07

    Predictions of Jupiter's electron and proton radiation belts are based mainly on decimeter observations of 1966 and 1968. Extensive calculations modeling radial diffusion of particles inward from the solar wind and electron synchrotron radiation are used to relate the predictions and observations.