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Sample records for technology uvb vacuum

  1. Handbook of vacuum technology

    CERN Document Server

    2016-01-01

    This comprehensive, standard work has been updated to remain an important resource for all those needing detailed knowledge of the theory and applications of vacuum technology. With many numerical examples and illustrations to visualize the theoretical issues.

  2. Technology handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is part of a series of publications that presents articles featuring the whole spectrum of vacuum physics. This particular volume presents materials that deal with technology concerns in vacuum mechanics. The first material talks about the utilization of ceramic materials in the construction of vacuum devices. The next paper details the application of vacuum physics in soldering and brazing process. The last article deals with the utilization of vacuum technology in high frequency heating. The book will be of great use to professionals involved

  3. Vacuum science, technology, and applications

    CERN Document Server

    Naik, Pramod K

    2018-01-01

    Vacuum plays an important role in science and technology. The study of interaction of charged particles, neutrals and radiation with each other and with solid surfaces requires a vacuum environment for reliable investigations. Vacuum has contributed immensely to advancements made in nuclear science, space, metallurgy, electrical/electronic technology, chemical engineering, transportation, robotics and many other fields. This book is intended to assist students, scientists, technicians and engineers to understand the basics of vacuum science and technology for application in their projects. The fundamental theories, concepts, devices, applications, and key inventions are discussed.

  4. Ultra high vacuum technology

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    A short introduction for some basic facts and equations. Subsquently, discussion about: Building blocks of an ultrahigh vacuum system - Various types of pumps required to reach uhv and methods to reduce these effects - Outgassing phenomena induced by the presence of a particle beam and the most common methods to reduce these effects It will be given some practical examples from existing CERN accelerators and discuss the novel features of the future LHC vacuum system.

  5. Vacuum Technology for Superconducting Devices

    CERN Document Server

    Chiggiato, P

    2014-01-01

    The basic notions of vacuum technology for superconducting applications are presented, with an emphasis on mass and heat transport in free molecular regimes. The working principles and practical details of turbomolecular pumps and cryopumps are introduced. The specific case of the Large Hadron Collider’s cryogenic vacuum system is briefly reviewed.

  6. Mirror fusion vacuum technology developments

    International Nuclear Information System (INIS)

    Batzer, T.H.; Call, W.R.

    1983-01-01

    Magnetic Mirror Fusion experiments, such as MFTF-B+T (Mirror Fusion Test Facility-B, Tritium Upgrade) and foreseeable follow-on devices, have operational and maintenance requirements that have not yet been fully demonstrated. Among those associated with vacuum technology are the very-high continuous-pumping speeds, 10 7 to 10 8 l/s for D 2 , T 2 and, to a lesser extent, He; the early detection of water leaks from the very-high heat-flux neutral-beam dumps and the detection and location of leaks in the superconducting magnets not protected by guard vacuums. Possible solutions to these problems have been identified and considerable progress has been made toward successfully demonstrating their feasibility

  7. Accelerator Technology: Ultra-High Vacuum

    CERN Document Server

    Baglin, V

    2013-01-01

    This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the the Section '8.5 Ultra-High Vacuum' of the Chapter '8 Accelerator Technology' with the content: 8.5 Ultra-High Vacuum 8.5.1 Introduction 8.5.2 Vacuum Fundamentals 8.5.3 Vacuum Dynamics 8.5.4 Vacuum Engineering

  8. Vacuum and ultravacuum physics and technology

    CERN Document Server

    Bello, Igor

    2018-01-01

    Vacuum technology has enormous impact on human life in many aspects and fields, such as metallurgy, material development and production, food and electronic industry, microelectronics, device fabrication, physics, materials science, space science, engineering, chemistry, technology of low temperature, pharmaceutical industry, and biology. All decorative coatings used in jewelries and various daily products—including shiny decorative papers, the surface finish of watches, and light fixtures—are made using vacuum technological processes. Vacuum analytical techniques and vacuum technologies are pillars of the technological processes, material synthesis, deposition, and material analyses—all of which are used in the development of novel materials, increasing the value of industrial products, controlling the technological processes, and ensuring the high product quality. Based on physical models and calculated examples, the book provides a deeper look inside the vacuum physics and technology.

  9. CAS CERN Accelerator School vacuum technology. Proceedings

    International Nuclear Information System (INIS)

    Turner, S.

    1999-01-01

    These proceedings present the lectures given at the twelfth specialized course organized by the CERN Accelerator School (CAS), the topic this time being 'Vacuum Technology'. Despite the importance of vacuum technology in the design and operation of particle accelerators at CERN and at the many other accelerators already installed around the world, this was the first time that CAS has organized a course devoted entirely to this topic. Perhaps this reflects the facts that vacuum has become one of the more critical aspects of future accelerators, and that many of the pioneers in the accelerator field are being replaced by new, younger personnel. The lectures start with the basic concepts of the physics and technology of vacuum followed by detailed descriptions of the many different types of gas-pumping devices and methods to measure the pressures achieved. The outgassing characteristics of the different materials used in the construction of vacuum systems and the optimisation of cleaning methods to reduce this outgassing are then explained together with the effects of the residual gases on the particle beams. Then follow chapters on leak detection, materials and vacuum system engineering. Finally, seminars are presented on designing vacuum systems, the history of vacuum devices, the LHC (large hadron collider) vacuum system, vacuum systems for electron storage rings, and quality assurance for vacuum. (orig.)

  10. Silicates materials of high vacuum technology

    CERN Document Server

    Espe, Werner

    2013-01-01

    Materials of High Vacuum Technology, Volume 2: Silicates covers silicate insulators of special importance to vacuum technology. The book discusses the manufacture, composition, and physical and chemical properties of technical glasses, quartz glass, quartzware, vycor glass, ceramic materials, mica, and asbestos.

  11. Vacuum Technology Considerations For Mass Metrology

    Science.gov (United States)

    Abbott, Patrick J.; Jabour, Zeina J.

    2011-01-01

    Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materials, plumbing components, pumping, and pressure gauging technologies. We review the vacuum technology1 required for mass metrology and suggest procedures and hardware for successful and reproducible operation. PMID:26989593

  12. Vacuum technology in the chemical industry

    CERN Document Server

    Jorisch, Wolfgang

    2015-01-01

    Based on the very successful German edition and a seminar held by the German Engineers` Association (VDI) on a regular basis for years now, this English edition has been thoroughly updated and revised to reflect the latest developments. It supplies in particular the special aspects of vacuum technology, applied vacuum pump types and vacuum engineering in the chemical, pharmaceutical and process industry application-segments. The text includes chapters dedicated to latest European regulations for operating in hazardous zones with vacuum systems, methods for process pressure control and regulati

  13. Steam vacuum cleaning. Innovative technology summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-05-01

    The US Department of Energy (DOE) continually seeks safer and more cost-effective remediation technologies for use in the decontamination and decommissioning (D and D) of nuclear facilities. The baseline technology currently used for washing debris is a high-pressure water cleaning (HPWC) system. The system used at the FEMP is the Hotsy{reg_sign} Model 550B HPWC. Although the HPWC technology has functioned satisfactorily, improvements are being sought in areas related to reduced liquid waste volume, increased productivity, increased washing effectiveness, and decreased airborne contamination. An innovative technology that offers potential improvements in these areas is a steam vacuum cleaning (SVC) system that integrates high-pressure steam cleaning with a vacuum recovery sub-system that simultaneously collects dislodged contaminants thereby reducing airborne contamination. The SVC system selected for demonstration at the FEMP was the Kelly{trademark} Decontamination System shown. This report provides comparative performance and cost analyses between the Hotsy HPWC system and the Kelly Decontamination System. Both technologies were demonstrated at the FEMP site located at Fernald, Ohio from July 29, 1996 through August 15, 1996. The demonstrations were conducted at the FEMP Plant 1 as part of the LSTD project sponsored by the Deactivation and Decommissioning Focus Area (DDFA) of the US DOE`s Office of Science and Technology.

  14. Steam vacuum cleaning. Innovative technology summary report

    International Nuclear Information System (INIS)

    1999-05-01

    The US Department of Energy (DOE) continually seeks safer and more cost-effective remediation technologies for use in the decontamination and decommissioning (D and D) of nuclear facilities. The baseline technology currently used for washing debris is a high-pressure water cleaning (HPWC) system. The system used at the FEMP is the Hotsy reg-sign Model 550B HPWC. Although the HPWC technology has functioned satisfactorily, improvements are being sought in areas related to reduced liquid waste volume, increased productivity, increased washing effectiveness, and decreased airborne contamination. An innovative technology that offers potential improvements in these areas is a steam vacuum cleaning (SVC) system that integrates high-pressure steam cleaning with a vacuum recovery sub-system that simultaneously collects dislodged contaminants thereby reducing airborne contamination. The SVC system selected for demonstration at the FEMP was the Kelly trademark Decontamination System shown. This report provides comparative performance and cost analyses between the Hotsy HPWC system and the Kelly Decontamination System. Both technologies were demonstrated at the FEMP site located at Fernald, Ohio from July 29, 1996 through August 15, 1996. The demonstrations were conducted at the FEMP Plant 1 as part of the LSTD project sponsored by the Deactivation and Decommissioning Focus Area (DDFA) of the US DOE's Office of Science and Technology

  15. Review of Current Nuclear Vacuum System Technologies

    International Nuclear Information System (INIS)

    Carroll, M.; McCracken, J.; Shope, T.

    2003-01-01

    Nearly all industrial operations generate unwanted dust, particulate matter, and/or liquid wastes. Waste dust and particulates can be readily tracked to other work locations, and airborne particulates can be spread through ventilation systems to all locations within a building, and even vented outside the building - a serious concern for processes involving hazardous, radioactive, or nuclear materials. Several varieties of vacuum systems have been proposed and/or are commercially available for clean up of both solid and liquid hazardous and nuclear materials. A review of current technologies highlights both the advantages and disadvantages of the various systems, and demonstrates the need for a system designed to address issues specific to hazardous and nuclear material cleanup. A review of previous and current hazardous/nuclear material cleanup technologies is presented. From simple conventional vacuums modified for use in industrial operations, to systems specifically engineered for such purposes, the advantages and disadvantages are examined in light of the following criteria: minimal worker exposure; minimal secondary waste generation;reduced equipment maintenance and consumable parts; simplicity of design, yet fully compatible with all waste types; and ease of use. The work effort reviews past, existing and proposed technologies in light of such considerations. Accomplishments of selected systems are presented, including identified areas where technological improvements could be suggested

  16. Introduction to vacuum technology: supplementary study material developed for IVS sponsored vacuum courses

    International Nuclear Information System (INIS)

    Bhusan, K.G.

    2008-01-01

    Vacuum technology has advanced to a large extent mainly from the demands of experimental research scientists who have more than ever understood the need for clean very low pressure environments. This need only seems to increase as the lowest pressures achievable in a laboratory setup are dropping down by the decade. What is not usually said is that conventional techniques of producing ultrahigh vacuum have also undergone a metamorphosis in order to cater to the multitude of restrictions in modern day scientific research. This book aims to give that practical approach to vacuum technology. The basics are given in the first chapter with more of a definition oriented approach - which is practically useful. The second chapter deals with the production of vacuum and ultrahigh vacuum with an emphasis on the working principles of several pumps and their working pressure ranges. Measurement of low pressures, both total and partial is presented in the third chapter with a note on leak detection and mass spectrometric techniques. Chapter 4 gives an overview of the materials that are vacuum compatible and their material properties. Chapter 5 gives the necessary methods to be followed for cleaning of vacuum components especially critical if ultrahigh vacuum environment is required. The practical use of a ultrahigh vacuum environment is demonstrated in Chapter 6 for production of high quality thin films through vapour deposition

  17. Ultra-high vacuum technology for accelerators

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit; Hilleret, Noël; Strubin, Pierre M

    2002-01-01

    The lectures will start with a review of the basics of vacuum physics required to build Ultra High Vacuum (UHV) systems, such as static and dynamic outgassing. Before reviewing the various pumping and measurement devices, including the most modern one like Non Evaporable Getter (NEG) coatings, an overview of adequate materials to be used in UHV systems will be given together with their treatment (e.g. cleaning procedures and bake out). Practical examples based on existing or future accelerators will be used to illustrate the topics. Finally, a short overview of modern vacuum controls and interlocks will be given.

  18. Materials for high vacuum technology, an overview

    CERN Document Server

    Sgobba, Stefano

    2007-01-01

    In modern accelerators stringent requirements are placed on materials of vacuum systems. Their physical and mechanical properties, machinability, weldability or brazeability are key parameters. Adequate strength, ductility, magnetic properties at room as well as low temperatures are important factors for vacuum systems of accelerators working at cryogenic temperatures, such as the Large Hadron Collider (LHC) under construction at CERN. In addition, baking or activation of Non-Evaporable Getters (NEG) at high temperatures impose specific choices of material grades of suitable tensile and creep properties in a large temperature range. Today, stainless steels are the dominant materials of vacuum constructions. Their metallurgy is extensively treated. The reasons for specific requirements in terms of metallurgical processes are detailed, in view of obtaining adequate purity, inclusion cleanliness, and fineness of the microstructure. In many cases these requirements are crucial to guarantee the final leak tightnes...

  19. Development of Beryllium Vacuum Chamber Technology for the LHC

    CERN Document Server

    Veness, R; Dorn, C

    2011-01-01

    Beryllium is the material of choice for the beam vacuum chambers around collision points in particle colliders due to a combination of transparency to particles, high specific stiffness and compatibility with ultra-high vacuum. New requirements for these chambers in the LHC experiments have driven the development of new methods for the manufacture of beryllium chambers. This paper reviews the requirements for experimental vacuum chambers. It describes the new beryllium technology adopted for the LHC and experience gained in the manufacture and installation.

  20. Vacuum technology Practice for scientific instruments

    CERN Document Server

    Yoshimura, Nagamitsu

    2008-01-01

    Nanotechnology has reached a level where almost every new development and even every new product uses features of nanoscopic properties of materials. As a consequence, an enormous amount of scientific instruments is used in order to synthesize and analyze new structures and materials. Due to the surface sensitivity of such materials, many of these instruments require ultrahigh vacuum that has to be provided under extreme conditions like very high voltages. In this book, Yoshimura provides a review of the UHV related development during the last decades. His very broad experience in the design enables him to present us this detailed reference. After a general description how to design UHV systems, he covers all important issue in detail, like pumps, outgasing, Gauges, and Electrodes for high voltages. Thus, this book serves as reference for everybody using UVH in his scientific equipment

  1. PREFACE: International Symposium on `Vacuum Science and Technology' (IVS 2007)

    Science.gov (United States)

    Mittal, K. C.; Gupta, S. K.

    2008-03-01

    The Indian Vacuum Society (established in 1970) has organized a symposium every alternate year on various aspects of vacuum science and technology. There has been considerable participation from R & D establishments, universities and Indian industry in this event. In view of the current global scenario and emerging trends in vacuum technology, this year, the executive committee of IVS felt it appropriate to organize an international symposium at Tata Institute of Fundamental Research, Colaba, Mumbai 400 005 from 29-30 November 2007. This symposium provided a forum for exchange of information among vacuum scientists, technologists and industrialists on recent advances made in the areas of large vacuum systems, vacuum production, its measurement and applications in industry, and material processing in vacuum. Vacuum science and technology has made vital contributions in high tech areas like space, high energy particle accelerators, large plasma systems, electronics, thin films, melting and refining of metals, extraction and processing of advanced materials etc. The main areas covered in the symposium were the production and measurement of vacuums, leak detection, large vacuum systems, vacuum metallurgy, vacuum materials and processing inclusive of applications of vacuum in industry. Large vacuum systems for high energy particle accelerators, plasma devices and light sources are of special significance for this symposium. Vacuum evaporation, hard coatings, thin films, joining techniques, sintering, melting and heat treatment, furnaces and thermo dynamics are also covered in this symposium. There were eighteen invited talks from the best experts in the respective fields and more than one hundred contributed papers. This fact itself indicates the interest that has been generated amongst the scientists, technologists and industrialists in this field. In view of the industrial significance of the vacuum technology, an exhibition of vacuum and vacuum processing related

  2. Handbook of vacuum science and technology

    National Research Council Canada - National Science Library

    Hoffman, Dorothy M; Singh, Bawa; Thomas, John H

    1998-01-01

    ... or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permissions may be sought directly from Elsevier's Science and Technology Rights Department in Oxford, UK. Phone: (44) 1865 843830, Fax: (44) 1865 853333. e-mail: permissions@elsevier.co.uk. You may also com...

  3. The vacuum system for technological unit development and design

    International Nuclear Information System (INIS)

    Zhukeshov, A M; Gabdullina, A T; Amrenova, A U; Giniyatova, Sh G; Kaibar, A; Sundetov, A; Fermakhan, K

    2015-01-01

    The paper shows results of development of plasma technological unit on the basis of accelerator of vacuum arc and automated system. During the previous years, the authors investigated the operation of pulsed plasma accelerator and developed unique technologies for hardening of materials. Principles of plasma formation in pulsed plasma accelerator were put into basis of the developed unit. Operation of the pulsed arc accelerator was investigated at different parameters of the charge. The developed vacuum system is designed for production of hi-tech plasma units in high technologies in fields of nanomaterials, mechanical and power engineering and production with high added value. Unlike integrated solutions, the system is a module one to allow its low cost, high reliability and simple maintenance. The problems of use of robots are discussed to modernize the technological process. (paper)

  4. Amorphous boron coatings produced with vacuum arc deposition technology

    CERN Document Server

    Klepper, C C; Yadlowsky, E J; Carlson, E P; Keitz, M D; Williams, J M; Zuhr, R A; Poker, D B

    2002-01-01

    In principle, boron (B) as a material has many excellent surface properties, including corrosion resistance, very high hardness, refractory properties, and a strong tendency to bond with most substrates. The potential technological benefits of the material have not been realized, because it is difficult to deposit it as coatings. B is difficult to evaporate, does not sputter well, and cannot be thermally sprayed. In this article, first successful deposition results from a robust system, based on the vacuum (cathodic) arc technology, are reported. Adherent coatings have been produced on 1100 Al, CP-Ti, Ti-6Al-4V, 316 SS, hard chrome plate, and 52 100 steel. Composition and thickness analyses have been performed by Rutherford backscattering spectroscopy. Hardness (H) and modules (E) have been evaluated by nanoindentation. The coatings are very pure and have properties characteristic of B suboxides. A microhardness of up to 27 GPa has been measured on a 400-nm-thick film deposited on 52 100 steel, with a corresp...

  5. Sewerage force adjustment technology for energy conservation in vacuum sanitation systems

    Science.gov (United States)

    Guo, Zhonghua; Li, Xiaoning; Kagawa, Toshiharu

    2013-03-01

    The vacuum sanitation is the safe and sound disposal approach of human excreta under the specific environments like flights, high speed trains and submarines. However, the propulsive force of current systems is not adjustable and the energy consumption does not adapt to the real time sewerage requirement. Therefore, it is important to study the sewerage force adjustment to improve the energy efficiency. This paper proposes an energy conservation design in vacuum sanitation systems with pneumatic ejector circuits. The sewerage force is controlled by changing the systematic vacuum degree according to the amount of the excreta. In particular, the amount of the excreta is tested by liquid level sensor and mass sensor. According to the amount of the excreta, the relationship between the excreta amount and the sewerage force is studied to provide proper propulsive force. In the other aspect, to provide variable vacuum degrees for different sanitation requirements, the suction and discharge system is designed with pneumatic vacuum ejector. On the basis of the static flow-rate characteristics and the vacuum generation model, the pressure response in the ejector circuit is studied by using the static flow rate characteristics of the ejector and air status equation. The relationship is obtained between supplied compressed air and systematic vacuum degree. When the compressed air is supplied to the ejector continuously, the systematic vacuum degree increases until the vacuum degree reaches the extreme value. Therefore, the variable systematic vacuum degree is obtained by controlling the compressed air supply of the ejector. To verify the effect of energy conservation, experiments are carried out in the artificial excreta collection, and the variable vacuum-degree design saves more than 30% of the energy supply. The energy conservation is realized effectively in the new vacuum sanitation systems with good application prospect. The proposed technology provides technological

  6. Feasibility study of vacuum technology integrated fused deposition ...

    African Journals Online (AJOL)

    vacuum pump connected will absorb the air inside the chamber until desire pressure while printing object. Mitutoyo SJ-301 portable surface roughness tester and optical microscope used to analyze the quality of surface finish. Result reveal with ...

  7. Application of vacuum technology during nuclear fuel fabrication, inspection and characterization

    International Nuclear Information System (INIS)

    Majumdar, S.

    2003-01-01

    Full text: Vacuum technology plays very important role during various stages of fabrication, inspection and characterization of U, Pu based nuclear fuels. Controlled vacuum is needed for melting and casting of U, Pu based alloys, picture framing of the fuel meat for plate type fuel fabrication, carbothermic reduction for synthesis of (U-Pu) mixed carbide powder, dewaxing of green ceramic fuel pellets, degassing of sintered pellets and encapsulation of fuel pellets inside clad tube. Application of vacuum technology is also important during inspection and characterization of fuel materials and fuel pins by way of XRF and XRD analysis, Mass spectrometer Helium leak detection etc. A novel method of low temperature sintering of UO 2 developed at BARC using controlled vacuum as sintering atmosphere has undergone successful irradiation testing in Cirus. The paper will describe various fuel fabrication flow sheets highlighting the stages where vacuum applications are needed

  8. Vacuum electronics

    CERN Document Server

    Eichmeier, Joseph A

    2008-01-01

    Nineteen experts from the electronics industry, research institutes and universities have joined forces to prepare this book. ""Vacuum Electronics"" covers the electrophysical fundamentals, the present state of the art and applications, as well as the future prospects of microwave tubes and systems, optoelectronics vacuum devices, electron and ion beam devices, light and X-ray emitters, particle accelerators and vacuum interrupters. These topics are supplemented by useful information about the materials and technologies of vacuum electronics and vacuum technology.

  9. Technological ion sources based on the vacuum arc discharge

    CERN Document Server

    Bugaev, S P; Oks, E M; Yushkov, G Y; Shchanin, P M; Braun, Y

    2001-01-01

    The Titan service ion sources are designed to generate wide-aperture high-current ion beams of gases or metals, as well as, mixed two-component gas and metal ion beams with the controllable ratio of components in a beam. This possibility is achieved via integration of two discharge systems in a source discharge system. To generate metal ions one uses a vacuum, arc discharge, while gas ions are generated by a low pressure contracted arc discharge with cold cathodes. The paper describes operation of these sources, their design, technical characteristics, peculiarities of their operation and application fields

  10. Applications of vacuum technology to novel accelerator problems

    Energy Technology Data Exchange (ETDEWEB)

    Garwin, E.L.

    1983-01-01

    Vacuum requirements for electron storage rings are most demanding to fulfill, due to the presence of gas desorption caused by large quantities of synchrotron radiation, the very limited area accessible for pumping ports, the need for 10/sup -9/ torr pressures in the ring, and for pressures a decade lower in the interaction regions. Design features of a wide variety of distributed ion sublimation pumps (DIP) developed at SLAC to meet these requirements are discussed, as well as NEG (non-evaporable getter) pumps tested for use in the Large Electron Positron Collider at CERN. Application of DIP to much higher pressures in electron damping rings for the Stanford Linear Collider are discussed.

  11. Applications of vacuum technology to novel accelerator problems

    International Nuclear Information System (INIS)

    Garwin, E.L.

    1983-01-01

    Vacuum requirements for electron storage rings are most demanding to fulfill, due to the presence of gas desorption caused by large quantities of synchrotron radiation, the very limited area accessible for pumping ports, the need for 10 -9 torr pressures in the ring, and for pressures a decade lower in the interaction regions. Design features of a wide variety of distributed ion sublimation pumps (DIP) developed at SLAC to meet these requirements are discussed, as well as NEG (non-evaporable getter) pumps tested for use in the Large Electron Positron Collider at CERN. Application of DIP to much higher pressures in electron damping rings for the Stanford Linear Collider are discussed

  12. Vacuum technology issues for the SSC [Superconducting Super Collider

    International Nuclear Information System (INIS)

    Joestlein, H.

    1989-01-01

    The Superconducting Super Collider, to be built in Texas, will provide an energy of 40 TeV from colliding proton beams. This energy is twenty times higher than currently available from the only other cryogenic collider, the Fermilab Tevatron, and will allow experiments that can lead to a better understanding of the fundamental properties of matter. The energy scale and the size of the new machine pose intriguing challenges and opportunities for the its vacuum systems. The discussion will include the effects of synchrotron radiation on cryogenic beam tubes, cold adsorption pumps for hydrogen, methods of leak checking large cryogenic systems, the development of cold beam valves, and radiation damage to components, especially electronics. 9 figs., 1 tab

  13. Ultrasonic Spray Drying vs High Vacuum and Microwaves Technology for Blueberries

    Science.gov (United States)

    Candia-Muñoz, N.; Ramirez-Bunster, M.; Vargas-Hernández, Y.; Gaete-Garretón, L.

    Interest in high quality foods: good taste and a high content of nutrients with healthy beneficial effects are increasing. Fruits have good properties but, they are lost because the oxidation process, additionally, for different reasons a 40% of harvested fruit are lost. To conserve the fruit properties an ultrasonic assisted spray dryer was developed and tested, comparing its results with microwave-vacuum drying technology. Results did shown taste, color, smell, particle shape and size distribution better than the conventional one. The antioxidants conservation were quite good except in the anthocyanins, in which the microwave and vacuum technology shown best results.

  14. The effects of cleaning and other treatments on the vacuum properties of technological materials used in ultra high vacuum

    International Nuclear Information System (INIS)

    Mathewson, A.G.

    1987-01-01

    Methods of producing atomically clean surfaces applicable to technological materials and large vacuum vassels where the surface area may attain tens or hundreds of square metres are described. As well as chemical cleaning methods, the efficency of treatments such as in situ glow discharge cleaning or heating to high temperature in vacuo are investigated. The techniques used to evaluate and compare the various treatments included thermal outgassing, Auger electron spectroscopy for chemical analysis of surface and near surface, ion, electron and X-ray induced neutral gas desorption, measurement of the quantity of desorbable surface gas by argon glow discharge and scanning electron microscope examination of the surface. In addition, by flash desorption, the binding energies of CO on some stainless steels were measured along with the roughness factor of the surface which gives a measure of the real surface area on which gas may be adsorbed

  15. Directed Vapor Deposition: Low Vacuum Materials Processing Technology

    National Research Council Canada - National Science Library

    Groves, J. F; Mattausch, G; Morgner, H; Hass, D. D; Wadley, H. N

    2000-01-01

    Directed vapor deposition (DVD) is a recently developed electron beam-based evaporation technology designed to enhance the creation of high performance thick and thin film coatings on small area surfaces...

  16. Apple snack enriched with L-arginine using vacuum impregnation/ohmic heating technology.

    Science.gov (United States)

    Moreno, Jorge; Echeverria, Julian; Silva, Andrea; Escudero, Andrea; Petzold, Guillermo; Mella, Karla; Escudero, Carlos

    2017-07-01

    Modern life has created a high demand for functional food, and in this context, emerging technologies such as vacuum impregnation and ohmic heating have been applied to generate functional foods. The aim of this research was to enrich the content of the semi-essential amino acid L-arginine in apple cubes using vacuum impregnation, conventional heating, and ohmic heating. Additionally, combined vacuum impregnation/conventional heating and vacuum impregnation/ohmic heating treatments were evaluated. The above treatments were applied at 30, 40 and 50  ℃ and combined with air-drying at 40 ℃ in order to obtain an apple snack rich in L-arginine. Both the impregnation kinetics of L-arginine and sample color were evaluated. The impregnated samples created using vacuum impregnation/ohmic heating at 50 ℃ presented a high content of L-arginine, an effect attributed primarily to electropermeabilization. Overall, vacuum impregnation/ohmic heating treatment at 50 ℃, followed by drying at 40 ℃, was the best process for obtaining an apple snack rich in L-arginine.

  17. CRYOGENIC AND VACUUM TECHNOLOGICAL ASPECTS OF THE LOW-ENERGY ELECTROSTATIC CRYOGENIC STORAGE RING

    International Nuclear Information System (INIS)

    Orlov, D. A.; Lange, M.; Froese, M.; Hahn, R. von; Grieser, M.; Mallinger, V.; Sieber, T.; Weber, T.; Wolf, A.; Rappaport, M.

    2008-01-01

    The cryogenic and vacuum concepts for the electrostatic Cryogenic ion Storage Ring (CSR), under construction at the Max-Planck-Institut fuer Kernphysik in Heidelberg, is presented. The ring will operate in a broad temperature range from 2 to 300 K and is required to be bakeable up to 600 K. Extremely high vacuum and low temperatures are necessary to achieve long lifetimes of the molecular ions stored in the ring so that the ions will have enough time to cool by radiation to their vibrational and rotational ground states. To test cryogenic and vacuum technological aspects of the CSR, a prototype is being built and will be connected to the commercial cryogenic refrigerator recently installed, including a specialized 2-K connection system. The first results and the status of current work with the prototype are also presented

  18. Evolution of gettering technologies for vacuum tubes to getters for MEMS

    Science.gov (United States)

    Amiotti, M.

    2008-05-01

    Getter materials are technically proven and industrially accepted practical ways to maintain vacuum inside hermetically sealed tubes or devices to assure high reliability and long lifetime of the operating devices. The most industrially proven vacuum tube is the cathode rays tubes (CRTs), where large surfaces are available for the deposition of an evaporated barium film by a radio frequency inductive heating of a stainless steel container filled with a BaAl4 powder mixed to Ni powder. The evolution of the CRTs manufacturing technologies required also new types of barium getters able to withstand some thermal process in air without any deterioration of the evaporation characteristics. In other vacuum tubes such as traveling waves tubes, the space available for the evaporation of a barium film and the sorption capacity required to assure the vacuum for the lifetime of the devices did not allow the use of the barium film, prompting the development of sintered non evaporable getter pills that can be activated during the manufacturing process or by flowing current through an embedded resistance. The same sintered non evaporable getter pills could find usage also in evacuated parts to thermally isolate the infrared sensors for different final applications. In high energy physics particle accelerators, the getter technology moved from localized vacuum getter pumps or getter strips to a getter coating over the surface of vacuum chambers in order to guarantee a more uniform pumping speed. With the advent of solid state electronics, new challenges faced the getter technology to assure long life to vacuum or inert gas filled hermetical packages containing microelectronic devices, especially in the telecommunication and military applications. A well known problem of GaAs devices with Pd or Pt metalization is the H2 poisoning of the metal gate: to prevent this degradation a two layer getter film has been develop to absorb a large quantity of H2 per unit of getter surface. The

  19. Evolution of gettering technologies for vacuum tubes to getters for MEMS

    Energy Technology Data Exchange (ETDEWEB)

    Amiotti, M [SAES Getters S.p.A., Viale Italia 77, 20020 Lainate, Milano (Italy)], E-mail: Marco_Amiotti@saes-group.com

    2008-05-01

    Getter materials are technically proven and industrially accepted practical ways to maintain vacuum inside hermetically sealed tubes or devices to assure high reliability and long lifetime of the operating devices. The most industrially proven vacuum tube is the cathode rays tubes (CRTs), where large surfaces are available for the deposition of an evaporated barium film by a radio frequency inductive heating of a stainless steel container filled with a BaAl{sub 4} powder mixed to Ni powder. The evolution of the CRTs manufacturing technologies required also new types of barium getters able to withstand some thermal process in air without any deterioration of the evaporation characteristics. In other vacuum tubes such as traveling waves tubes, the space available for the evaporation of a barium film and the sorption capacity required to assure the vacuum for the lifetime of the devices did not allow the use of the barium film, prompting the development of sintered non evaporable getter pills that can be activated during the manufacturing process or by flowing current through an embedded resistance. The same sintered non evaporable getter pills could find usage also in evacuated parts to thermally isolate the infrared sensors for different final applications. In high energy physics particle accelerators, the getter technology moved from localized vacuum getter pumps or getter strips to a getter coating over the surface of vacuum chambers in order to guarantee a more uniform pumping speed. With the advent of solid state electronics, new challenges faced the getter technology to assure long life to vacuum or inert gas filled hermetical packages containing microelectronic devices, especially in the telecommunication and military applications. A well known problem of GaAs devices with Pd or Pt metalization is the H{sub 2} poisoning of the metal gate: to prevent this degradation a two layer getter film has been develop to absorb a large quantity of H{sub 2} per unit of

  20. Feasibilty study of renewable energy powered seawater desalination technology using natural vacuum technique

    Energy Technology Data Exchange (ETDEWEB)

    Ayhan, Teoman; Al Madani, Hussain [Mechanical Engineering Department, College of Engineering, University of Bahrain, P.O. box 32038, Isatown 32036 (Bahrain)

    2010-02-15

    With an ever-increasing population and rapid growth of industrialization, there is great demand for fresh water. Desalination has been a key proponent to meet the future challenges due to decreasing availability of fresh water. However, desalination uses significant amount of energy, today mostly from fossil fuels. It is, therefore, reasonable to rely on renewable energy sources such as solar energy, wind energy, ocean thermal energy, waste heat from the industry and other renewable sources. The present study deals with the energy-efficient seawater desalination system utilizing renewable energy sources and natural vacuum technique. A new desalination technology named Natural Vacuum Desalination is proposed. The novel desalination technique achieve remarkable energy efficiency through the evaporation of seawater under vacuum and will be described in sufficient detail to demonstrate that it requires much less electric energy compared to any conventional desalination plant of fresh water production of similar capacity. The discussion will highlight the main operative and maintenance features of the proposed natural vacuum seawater desalination technology which seems to have promising techno-economic potential providing also advantageous coupling with renewable energy sources. (author)

  1. Proceedings of the Japan-U.S. workshop P-118 on vacuum technologies for fusion devices

    International Nuclear Information System (INIS)

    Miyahara, A.

    1989-01-01

    Fusion community does not appreciate vacuum technologies to the same extent as accelerator community does. This is because, in the case of accelerators, in particular storage ring systems, the requirement of attaining ultrahigh vacuum in order to avoid collisional loss is well defined, on the other hand, it is not possible to define the requirement so precisely in the case of fusion devices. One of the reasons is that core plasma interacts with vessel wall so strongly and unpredictably that it becomes difficult to identify the role played by individual components. However, in the next step and the next generation machines like CIT, LHS, ITER, FER and NET, vacuum technologies would play more significant roles, because the CIT will introduce tritium in a vacuum vessel, and the aim of the ITER project is to demonstrate particle balance, namely, to achieve steady state operation with D-T fuel. The Japan-U.S. workshop P-118 was held at the Institute of Plasma Physics, Nagoya University, from August 1 to 5, 1988. 33 participants including 4 from the U.S. took part in the workshop. In the plenary session, 12 lectures were given, and also the topics-oriented session on pumping, gauging, remote maintenance, first wall, pump limiter, divertor and others was held. (K.I.)

  2. PREFACE: International Symposium on Vacuum Science & Technology and its Application for Accelerators (IVS 2012)

    Science.gov (United States)

    Pandit, V. S.; Pal, Gautam

    2012-11-01

    The Indian Vacuum Society (IVS) was established in 1970 to promote vacuum science and technology in academic, industrial and R&D institutions in India. IVS is a member society of the International Union for Vacuum Science, Technique and Applications (IUVSTA). It has organized International and national symposia, short term courses and workshops on different aspects of Vacuum Science and Technology at regular intervals. So far 27 National symposia, 4 International Symposia and 47 courses have been organized at various locations in India. There has been an active participation from R&D establishments, universities and Indian industries during all these events. In view of the current global situation and emerging trends in vacuum technology, the executive committee of the IVS suggested to us that we organize an International Symposium at the Variable Energy Cyclotron Centre, Kolkata from 15-17 February 2012. At the Variable Energy Cyclotron Centre we have a large number of high vacuum systems used in the K130 Cyclotron and K500 Superconducting Cyclotron. Also a large cryogenic system using LHe plant is in operation for cryopanels and a superconducting magnet for K-500 Cyclotron. The main areas covered at the symposium were the production and measurement of vacuums, leak detection, design and development of large vacuum systems, vacuum metallurgy, vacuum materials and the application of high vacuums in cyclotrons, LINACS and other accelerators. This symposium provided an opportunity for interaction between active researchers and technologists and allowed them to review the current situation, report recent experimental results, share the available expertise and consider the future R&D efforts needed in this area. Keeping the industrial significance of vacuum technology in mind, an exhibition of the vacuum related equipment, accessories, products etc by various suppliers and manufactures was organized alongside the symposium. Participation by a large number of exhibitors

  3. Scientometric mapping of vacuum research in nuclear science and technology: a global perspective

    International Nuclear Information System (INIS)

    Kademani, B S; Sagar, A; Kumar, A; Kumar, V

    2008-01-01

    This paper attempts to analyse the growth and development of Vacuum research in Nuclear Science and Technology, as reflected in publication output covered by International Nuclear Information System (INIS) database during 2002-2006. A total of 12027 papers were published in the field of vacuum science. United States topped the list with 1936 (16.10%) publications followed by Japan with 1770 (14.70%) publications, The highest number of publications (3276) were published in 2004. The average number of publications published per year were 2405.4. The highest number of publications were in 'Physics of Elementary Particles and Fields' with 2644 (21.98%) publications. The authorship and collaboration trend is towards multi-authored papers. The highly productive institutions were: Japan Atomic Energy Research Institute (Japan) with 366 publications, University of Tokyo (Japan) with 274 publications, Hiroshima University (Japan) with 245 publications, Osaka University Japan (Japan) with 224 publications and Chinese Academy of Science (P-R-China) with 223 publications. The most preferred journals for publication were: Journal of Vacuum Science and Technology-A with 857 papers, Physical Review -D with 765 papers, Journal of High Energy Physics with 500 papers, Thin Solid Films with 311 papers, Journal of Electron Spectroscopy and Related Phenomena with 309 papers, and AIP Conference Proceedings with 308 papers

  4. LCA of strippable coatings and of steam vacuum technology used for nuclear plants decontamination

    International Nuclear Information System (INIS)

    Guidi, Giambattista; Cumo, Fabrizio; Santoli, Livio de

    2010-01-01

    The application of strippable coatings is an innovative technology for decontamination of nuclear plants and for any decontamination project aiming at removing surface contamination. An adhesive plastic coating is applied on the contaminated surface. The strippable coating is allowed to cure for up to 24 h, after which it can be easily peeled. The coating traps the contaminants in the polymer matrix. Strippable coatings are non-toxic and do not contain volatile compounds or heavy metals. Since the coating constitutes a solid waste, disposal is easier than treating contaminated liquid wastes, produced by the baseline technology: steam vacuum cleaning, based upon superheated pressurized water in order to remove contaminants from floors and walls. A life cycle assessment (LCA) has been carried out with the purpose of comparing the strippable coating with the steam vacuum technology. The functional unit of the study is represented by a surface of 1 m 2 to be decontaminated. The results of LCA achieved using Sima Pro 5.0 registered software confirm the good environmental performances of strippable coatings. Taking into account both LCA and environmental costs for liquid wastes, the advantages of strippable coatings will be more and more evident. (orig.)

  5. "Physics Stories": How the Early Technologies of High Voltage and High Vacuum Led to "Modern Physics"

    Science.gov (United States)

    Greenslade, Thomas B.

    2018-05-01

    Some of you may remember the 1979 television series "Connections" that was written and narrated by James Burke, a British science writer. Burke's technique was to choose a number of seemingly unrelated ideas and show how they led to developments in science and technology. This is an enjoyable business, even if some of the connections seem to be stretched at times, and led to a book by Burke. In a number of talks that I have given over the years, I have made somewhat less fanciful connections that suggest how the technologies of high vacuum and high voltage led to what used to be called "modern physics." Today we might limit the "modern" era to the years from 1890 to 1920 that gave the first workable theories of small-scale physics.

  6. Vacuum mechatronics

    Science.gov (United States)

    Hackwood, Susan; Belinski, Steven E.; Beni, Gerardo

    1989-01-01

    The discipline of vacuum mechatronics is defined as the design and development of vacuum-compatible computer-controlled mechanisms for manipulating, sensing and testing in a vacuum environment. The importance of vacuum mechatronics is growing with an increased application of vacuum in space studies and in manufacturing for material processing, medicine, microelectronics, emission studies, lyophylisation, freeze drying and packaging. The quickly developing field of vacuum mechatronics will also be the driving force for the realization of an advanced era of totally enclosed clean manufacturing cells. High technology manufacturing has increasingly demanding requirements for precision manipulation, in situ process monitoring and contamination-free environments. To remove the contamination problems associated with human workers, the tendency in many manufacturing processes is to move towards total automation. This will become a requirement in the near future for e.g., microelectronics manufacturing. Automation in ultra-clean manufacturing environments is evolving into the concept of self-contained and fully enclosed manufacturing. A Self Contained Automated Robotic Factory (SCARF) is being developed as a flexible research facility for totally enclosed manufacturing. The construction and successful operation of a SCARF will provide a novel, flexible, self-contained, clean, vacuum manufacturing environment. SCARF also requires very high reliability and intelligent control. The trends in vacuum mechatronics and some of the key research issues are reviewed.

  7. A Brief Review on Metamaterial-Based Vacuum Electronics for Terahertz and Microwave Science and Technology

    Science.gov (United States)

    Matsui, Tatsunosuke

    2017-09-01

    Metamaterials, which enable us to realize novel physical effects that cannot be achieved using natural materials, have been extensively studied in recent years and significant progress has been made, especially in the field of optics. This game-changing concept has also initiated a rich variety of research activity in vacuum electronics. Here we review the recent development of metamaterial-based vacuum electronics for terahertz (THz) and microwave science and technology. The reversed Cherenkov radiation (RCR) in double-negative (DNG) metamaterials predicted by Veselago back in the 1960s has been experimentally verified in the microwave frequency range by utilizing specially designed DNG metamaterials. The interaction of an electron beam (e-beam) with DNG metamaterials may lead to the realization of novel applications such as microwave and THz radiation sources, accelerators, and even the visualization of invisibility cloaks. Smith-Purcell radiation (SPR) has recently received renewed interest owing to the development of metamaterials and the concept of spoof surface plasmon polaritons, as discussed in this review, and recent results on e-beam-induced directional and wide-band THz radiation with sharp multiple peaks from a graded grating, as well as directional and monochromatic special SPR and their possible application to THz orotron devices, are also reviewed.

  8. Technology Demonstration Summary: Terra Vac In Situ Vacuum Extraction System, Groveland, Massachusetts

    Science.gov (United States)

    Terra Vac Inc's vacuum extraction system was demonstrated at the Valley Manufactured Products Company, Inc., site in Groveland, Massachusetts. The property is part of the Groveland Wells Superfund site and is contaminated mainly by trichloroethylene (TCE). Vacuum extraction...

  9. Automatic Vacuum Flushing Technology for Combined Sewer Solids: Laboratory Testing and Proposed Improvements (WERF Report INFR7SG09)

    Science.gov (United States)

    This research study included an extensive literature review on existing sewer sediment flushing technologies. An innovative vacuum flush system previously developed by the U.S. EPA was tested under laboratory conditions. The tests revealed a strong correlation between the strengt...

  10. Modern vacuum practice

    CERN Document Server

    Harris, Nigel

    2007-01-01

    Modern Vacuum Practice is an easy-to-understand introduction to high vacuum technology suitable for anyone using high vacuum as a tool. The author provides a fundamentally non-mathematical treatment of the subject, assuming little or no prior vacuum knowledge throughout. With its emphasis always on providing practical information, the book gives the reader the knowledge to set up, use, maintain and troubleshoot a vacuum system.

  11. Challenges of in-vacuum and cryogenic permanent magnet undulator technologies

    Directory of Open Access Journals (Sweden)

    Jui-Che Huang

    2017-06-01

    Full Text Available An in-vacuum undulator (IVU provides a means to reach high-brilliance x rays in medium energy storage rings. The development of short period undulators with low phase errors creates the opportunity for an unprecedented brilliant light source in a storage ring. Since the spectral quality from cryogenic permanent magnet undulators (CPMUs has surpassed that of IVUs, NdFeB or PrFeB CPMUs have been proposed for many new advanced storage rings to reach high brilliance x-ray photon beams. In a low emittance ring, not only the performance of the undulator but also the choice of the lattice functions are important design considerations. Optimum betatron functions and a zero-dispersion function shall be provided in the straight sections for IVU/CPMUs. In this paper, relevant factors and design issues for IVUs and CPMUs are discussed together with many technological challenges in short period undulators associated with beam induced–heat load, phase errors, and the deformation of support girders.

  12. Challenges of in-vacuum and cryogenic permanent magnet undulator technologies

    Science.gov (United States)

    Huang, Jui-Che; Kitamura, Hideo; Yang, Chin-Kang; Chang, Cheng-Hsing; Chang, Cheng-Hsiang; Hwang, Ching-Shiang

    2017-06-01

    An in-vacuum undulator (IVU) provides a means to reach high-brilliance x rays in medium energy storage rings. The development of short period undulators with low phase errors creates the opportunity for an unprecedented brilliant light source in a storage ring. Since the spectral quality from cryogenic permanent magnet undulators (CPMUs) has surpassed that of IVUs, NdFeB or PrFeB CPMUs have been proposed for many new advanced storage rings to reach high brilliance x-ray photon beams. In a low emittance ring, not only the performance of the undulator but also the choice of the lattice functions are important design considerations. Optimum betatron functions and a zero-dispersion function shall be provided in the straight sections for IVU/CPMUs. In this paper, relevant factors and design issues for IVUs and CPMUs are discussed together with many technological challenges in short period undulators associated with beam induced-heat load, phase errors, and the deformation of support girders.

  13. PREFACE: 16th International Summer School on Vacuum, Electron, and Ion Technologies (VEIT 2009)

    Science.gov (United States)

    Möller, Wolfhard; Guerassimov, Nikolay; Ghelev, Chavdar

    2010-04-01

    The International Summer School on Vacuum, Electron and Ion Technologies (VEIT) has been organized biennially since 1977 when the series of VEIT Schools was launched by the Institute of Electronics, Bulgarian Academy of Sciences with the aim to act as a forum for interchange and dissemination of knowledge and ideas on the latest developments in electron-, ion-, and plasma-assisted technologies. Beginning from 2001, the school has been jointly organized with the Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, Germany. Whereas, the school initially provided a meeting place for researchers mainly from Eastern and Central European countries, its importance grew issue by issue. The school is now a major scientific event and a meeting place for young scientists from Eastern and Western Europe involved in research and development associated with high-tech industries. Many former school participants have gone on to become leading scientists in research establishments and companies throughout the world. Leading international companies, such as High Voltage Engineering, Balzers, Varian, and Hauzer have used the VEIT forum to present their products through oral presentations, poster contributions or exhibits. The School Proceedings have been published in special issues of the international journals Vacuum, Plasma Processes and Polymers, Journal of Physics: Conference Series. The Sixteenth VEIT school was held in the Black Sea resort Sunny Beach, Bulgaria on 28 September to 2 October 2009. It was attended by close to 110 participants from 13 countries: Belgium, Bulgaria, Czech Republic, France, Germany, The Netherlands, Romania, Slovak Republic, Spain, Sweden, Ukraine, UK and USA. Following the tradition of publishing the VEIT Proceedings, a selection of papers presented at the event is published in this volume of Journal of Physics: Conference Series, under the originality and quality criteria of acceptance by the journal, including

  14. Ethanol production from food waste at high solids content with vacuum recovery technology.

    Science.gov (United States)

    Huang, Haibo; Qureshi, Nasib; Chen, Ming-Hsu; Liu, Wei; Singh, Vijay

    2015-03-18

    Ethanol production from food wastes does not only solve environmental issues but also provides renewable biofuels. This study investigated the feasibility of producing ethanol from food wastes at high solids content (35%, w/w). A vacuum recovery system was developed and applied to remove ethanol from fermentation broth to reduce yeast ethanol inhibition. A high concentration of ethanol (144 g/L) was produced by the conventional fermentation of food waste without a vacuum recovery system. When the vacuum recovery is applied to the fermentation process, the ethanol concentration in the fermentation broth was controlled below 100 g/L, thus reducing yeast ethanol inhibition. At the end of the conventional fermentation, the residual glucose in the fermentation broth was 5.7 g/L, indicating incomplete utilization of glucose, while the vacuum fermentation allowed for complete utilization of glucose. The ethanol yield for the vacuum fermentation was found to be 358 g/kg of food waste (dry basis), higher than that for the conventional fermentation at 327 g/kg of food waste (dry basis).

  15. EDITORIAL: 17th International Summer School on Vacuum, Electron, and Ion Technologies (VEIT 2011)

    Science.gov (United States)

    van de Sanden, M. C. M.; Dimitrova, Miglena; Ghelev, Chavdar

    2012-03-01

    The International Summer School on Vacuum, Electron and Ion Technologies (VEIT) has been organized biennially since 1977, when the VEIT Summer School series was launched by the Institute of Electronics, Bulgarian Academy of Sciences. The aim was to act as a forum for the exchange and dissemination of knowledge and ideas on the latest developments in electron-, ion- and plasma-assisted technologies. The organizers of the 2011 edition of the event were the Institute of Electronics, Bulgarian Academy of Sciences, Sofia, Bulgaria and the Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands. Whilst the school initially provided a meeting place for researchers mainly from Eastern and Central European countries, its importance has grown issue by issue. The school is now a major scientific event and a meeting place for young scientists from Eastern and Western Europe involved in research and development associated with high-tech industries. Many former school participants have gone on to become leading scientists in research establishments and companies throughout the world. Leading international companies, such as High Voltage Engineering, Balzers, Varian, and Hauzer have used the VEIT forum to present their products through oral presentations, poster contributions and exhibits. The School Proceedings have been published in special issues of the international journals Vacuum, Plasma Processes and Polymers and Journal of Physics: Conference Series. The Seventeenth edition of VEIT was held in the Black Sea resort of Sunny Beach, Bulgaria on 19-23 September 2011. It was attended by 96 participants from 18 countries: Belgium, Brazil, Bulgaria, Czech Republic, Denmark, France, Germany, Greece, The Netherlands, Romania, Russia, Serbia, Sweden, Switzerland, Turkey, Ukraine, UK and USA. Following the tradition of publishing the VEIT Proceedings, a selection of papers presented at the event is published in this special issue of Journal of

  16. Historical review of the vacuum chamber technology for INS-ES

    International Nuclear Information System (INIS)

    Yoshida, Katsuhide

    2006-01-01

    The INS (Institute for Nuclear Study), University of Tokyo, was founded in 1955. Construction of the ES (electron synchrotron) was approved in 1956 and finished in 1961. 1.3 GeV INS-ES consists of 8 electric magnets with 3.14m length at intervals of 1.2m. It used resonant exciting current. The vacuum chamber was called donut made of ceramics at first and changed by araldite in 1964, and metal in 1970's. 53% of troubles were caused by the vacuum system in 1966. The metal donut with stainless steel welding bellows was changed by the stainless steel from SUS304 to SUS316L. These improvement methods solved the vacuum problems. The donut made of araldite, a trial piece of stainless steel welding bellows, increase of beam intensity of INS-ES and position of stainless steel welding bellows in section are shown. (S.Y.)

  17. Technological plasma source equipped with combined system of vacuum-arc discharge initiation

    International Nuclear Information System (INIS)

    Sysoev, Yu.O.

    2013-01-01

    The construction and the operation principle of erosion plasma source with a three-stage system of vacuum-arc discharge excitation is described. As first two step was used the modified contactless start system with plasma injector, which was widely used in standard plasma sources of the ''Bulat'' systems. The operation principle of the third stage was based on the transition of glow discharge to arc discharge. Coordinated operation of three stages during various stages of coating deposition provided significant increasing of service life and reliability of the system of vacuum-arc discharge initiation and extended the functionality of the plasma source

  18. Filling the vacuum chamber of a technological system with homogeneous plasma using a stationary glow discharge

    International Nuclear Information System (INIS)

    Metel, A. S.; Grigoriev, S. N.; Melnik, Yu. A.; Panin, V. V.

    2009-01-01

    Experimental study of a glow discharge with electrostatic confinement of electrons is carried out in the vacuum chamber volume V ∼ 0.12 m 3 of a technological system 'Bulat-6' in argon pressure range 0.005-5 Pa. The chamber is used as a hollow cathode of the discharge with the inner surface area S ∼ 1.5 m 2 . It is equipped with two feedthroughs, which make it possible to immerse in the discharge plasma interchangeable anodes with surface area S a ranging from ∼0.001 to ∼0.1 m 2 , as well as floating electrodes isolated from both the chamber and the anode. Dependences of the cathode fall U c = 0.4-3 kV on the pressure p at a constant discharge current in the range I = 0.2-2 A proved that aperture of the electron escape out of the electrostatic trap is equal to the sum S o = S a + S f of the anode surface S a and the floating electrode surface S f . The sum S o defines the lower limit p o of the pressure range, in which U c is independent of p. At p o the cathode fall U c grows up dramatically, when the pressure decreases, and the pressure p tends to the limit p ex , which is in fact the discharge extinction pressure. At p ∼ p ex electrons emitted by the cathode and the first generation of fast electrons produced in the cathode sheath spend almost all their energy up to 3 keV on heating the anode and the floating electrode up to 600-800 o C and higher. In this case the gas in the chamber is being ionized by the next generations of electrons produced in the cathode sheath, their energy being one order of magnitude lower. When S a 1/2 S, where m is the electron mass and M is the ion mass, the anode may be additionally heated by plasma electrons accelerated by the anode fall of potential U a up to 0.5 kV.

  19. Development of Deep Penetration Welding Technology with High Brightness Laser under Vacuum

    Science.gov (United States)

    Katayama, Seiji; Yohei, Abe; Mizutani, Masami; Kawahito, Yousuke

    The authors have developed a new chamber for laser welding under the low vacuum conditions achieved by using rotary pumps. High-power disk laser bead-on-plate welding was performed on Type 304 stainless steel or A5052 aluminium alloy plate at the powers of 10, 16 and 26 kW at various welding speeds under low vacuum. The sound welds of more than 50 and 70 mm in penetration depth could be produced in Type 304 at the pressure of 0.1 kPa, the speed of 0.3 m/min and the power of 16 kW and 26 kW, respectively. Similar penetration was achieved in A 5052 aluminum alloy. Welding phenomena under low vacuum were also understood by observing the behavior of a keyhole inlet, a molten pool, melt flows and a plume ejected from a keyhole through high speed video cameras. Low interaction between a laser beam and a plume under low vacuum was confirmed by using probe laser beam method.

  20. 19th International Summer School on Vacuum, Electron and Ion Technologies (VEIT2015)

    International Nuclear Information System (INIS)

    2016-01-01

    The International Summer School on Vacuum, Electron and Ion Technologies (VEIT) has been organized biennially since 1978, when the series of VEIT Schools was launched by the Institute of Electronics, Bulgarian Academy of Sciences with the aim to act as a forum for exchange and dissemination of knowledge and ideas on the latest developments in electron-, ion-, and plasma-assisted technologies. The organizers of the 2015 edition of the event were the Institute of Electronics, Bulgarian Academy of Sciences, Sofia, Bulgaria and the Dutch Institute for Fundamental Energy Research, Eindhoven, The Netherlands. While the school has initially been providing a meeting place for researchers mainly from Eastern and Central European countries, its importance has grown issue by issue. The school is now a major scientific event and a meeting place for young scientists from Eastern and Western Europe involved in research and development associated with high-tech industries. Many former school participants have gone on to become leading scientists in research establishments and companies throughout the world. Leading international companies, such as High Voltage Engineering, Balzers, Varian, and Hauzer have used the VEIT forum to present their products through oral presentations, poster contributions or exhibits. The School Proceedings have been published in special issues of the international journals Vacuum, Plasma Processes and Polymers, Journal of Physics: Conference Series. The Nineteenth edition of VEIT was held in the Black Sea resort Sozopol, Bulgaria, on 21--25 September 2015. It was attended by 101 participants from 16 countries: Bulgaria, Czech Republic, France, Germany, Greece, The Netherlands, Portugal, Romania, Russia, Serbia, Slovakia, Slovenia, Sweden, Turkey, Ukraine and UK. Following the tradition of publishing the VEIT Proceedings, a selection of papers presented at the event are published in this special issue of Journal of Physics: Conference Series, under the

  1. Nanoscale Vacuum Channel Transistor.

    Science.gov (United States)

    Han, Jin-Woo; Moon, Dong-Il; Meyyappan, M

    2017-04-12

    Vacuum tubes that sparked the electronics era had given way to semiconductor transistors. Despite their faster operation and better immunity to noise and radiation compared to the transistors, the vacuum device technology became extinct due to the high power consumption, integration difficulties, and short lifetime of the vacuum tubes. We combine the best of vacuum tubes and modern silicon nanofabrication technology here. The surround gate nanoscale vacuum channel transistor consists of sharp source and drain electrodes separated by sub-50 nm vacuum channel with a source to gate distance of 10 nm. This transistor performs at a low voltage (3 microamperes). The nanoscale vacuum channel transistor can be a possible alternative to semiconductor transistors beyond Moore's law.

  2. PREFACE: Fifteenth International Summer School on Vacuum, Electron and Ion Technologies (VEIT 2007)

    Science.gov (United States)

    Guerassimov, Nikolay; Möller, Wolfhard; Ghelev, Chavdar

    2008-03-01

    The International Summer School on Vacuum, Electron and Ion Technologies (VEIT) has been organized biannually since 1977. It is a forum for the interchange and dissemination of knowledge and ideas on the latest developments in electron-, ion-, and plasma-assisted technologies. The organizers of the event (since 2001) have been the Institute of Electronics, Bulgarian Academy of Sciences, Sofia, Bulgaria, the Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, Dresden, Germany, and the Evrika Foundation, Sofia, Bulgaria. The fifteenth meeting of VEIT was held in the Black Sea resort of Sozopol, Bulgaria from 17-21 September 2007 and was attended by around 120 participants from 17 countries: Australia, Belgium, Bulgaria, Canada, Czech Republic, Germany, Hungary, Italy, The Netherlands, Poland, Pakistan, Romania, Sweden, Switzerland, Ukraine, UK and USA. Following the tradition of publishing the VEIT Proceedings, a selection of papers presented at the event is published in this volume of Journal of Physics: Conference Series, all peer reviewed to meet the originality and quality criteria of the journal. The school consisted of 11 oral and 3 poster sessions. There were 17 invited talks of general interest and 12 progress reports were presented orally. In total 86 contributed papers were presented during the three poster sessions. There were several scientific highlights covering the fundamentals of gas discharges and interaction of fast particles with solids, a wide range of conventional and novel applications such as for hard coatings and optical/protective layers, nanosized structures produced by evaporation, sputtering or external irradiation. Recent achievements in the modification of materials using charged particles or laser beams, thin layers deposition, properties, and characterization and novel materials, techniques, devices were highlighted. Despite the busy scientific program, the atmosphere was relaxed and informal

  3. Thermal Characterization of the Air Force Institute of Technology Solar Simulation Thermal Vacuum Chamber

    Science.gov (United States)

    2014-03-27

    VACUUM CHAMBER I. Introduction Motivation The CubeSat class of nanosatellites continues to become a preferred choice for Department of Defense...DoD) and university research satellites. A CubeSat is specifically defined as a nanosatellite made of a combination of one to six approximately...School (NPS), Smith generated a thermal model of the NPS Solar Cell Array Tester (NPS-SCAT) nanosatellite [4]. Smith developed the thermal model in

  4. Vacuum Induction Melting and Investment Casting Technologies Tailored to Near-Gamma TiAl Alloys

    Czech Academy of Sciences Publication Activity Database

    Dlouhý, Antonín; Dočekalová, Kateřina; Zemčík, L.

    2007-01-01

    Roč. 539-543, - (2007), s. 1463-1468 ISSN 0255-5476. [Thermec 2006. Vancouver, 04.06.2006-08.06.2006] R&D Projects: GA AV ČR 1QS200410502; GA ČR GA106/04/0853 Institutional research plan: CEZ:AV0Z20410507 Keywords : Intermetallics * Gamma TiAl * Vacuum Induction Melting Subject RIV: JG - Metallurgy Impact factor: 0.399, year: 2005

  5. In vitro study of platelet function confirms the contribution of the ultraviolet B (UVB) radiation in the lesions observed in riboflavin/UVB-treated platelet concentrates.

    Science.gov (United States)

    Abonnenc, Mélanie; Sonego, Giona; Crettaz, David; Aliotta, Alessandro; Prudent, Michel; Tissot, Jean-Daniel; Lion, Niels

    2015-09-01

    Platelet inactivation technologies (PITs) have been shown to increase platelet storage lesions (PSLs). This study investigates amotosalen/ultraviolet (UV)A- and riboflavin/UVB-induced platelet (PLT) lesions in vitro. Particular attention is given to the effect of UVB alone on PLTs. Buffy coat-derived PLT concentrates (PCs) were treated with amotosalen/UVA, riboflavin/UVB, or UVB alone and compared to untreated PCs throughout storage. In vitro PLT function was assessed by blood gas and metabolite analyses, flow cytometry-based assays (CD62P, JC-1, annexin V, PAC-1), hypotonic shock response, and static adhesion to fibrinogen-coated wells. In our experimental conditions, riboflavin/UVB-treated PCs showed the most pronounced differences compared to untreated and amotosalen/UVA-treated PCs. The riboflavin/UVB treatment led to a significant increase of anaerobic glycolysis rate despite functional mitochondria, a significant increase of CD62P on Day 2, and a decrease of JC-1 aggregates and increase of annexin V on Day 7. The expression of active GPIIbIIIa (PAC-1) and the adhesion to fibrinogen was significantly increased from Day 2 of storage in riboflavin/UVB-treated PCs. Importantly, we showed that these lesions were caused by the UVB radiation alone, independently of the presence of riboflavin. The amotosalen/UVA-treated PCs confirmed previously published results with a slight increase of PSLs compared to untreated PCs. Riboflavin/UVB-treated PCs present significant in vitro PSLs compared to untreated PCs. These lesions are caused by the UVB radiation alone and probably involve the generation of reactive oxygen species. The impact of these observations on clinical use must be investigated. © 2015 AABB.

  6. UVB: suscetibilidade no melanoma maligno UVB: susceptibility in malignant melanoma

    Directory of Open Access Journals (Sweden)

    Nilton Nasser

    2010-12-01

    Full Text Available FUNDAMENTOS: Está bem definido que a radiação ultravioleta provoca depleção imunológica na pele, permitindo o desenvolvimento de tumores cutâneos malignos. A maioria dos pacientes de cânceres da pele não melanomas são considerados UVB-suscetíveis. OBJETIVOS: Estudar a UVB-suscetibilidade nos pacientes com melanoma maligno e se este é um fator de risco para o desenvolvimento desse câncer. MÉTODOS: Foram selecionados 88 voluntários divididos em dois grupos: grupo-controle saudável (n=61 e grupo de portadores de melanoma (n=27, todos identificados de acordo com os critérios: tipo histológico, nível de invasão, fotótipos de pele, sexo e idade. A suscetibilidade à radiação ultravioleta B (UVB foi medida pela reação de hipersensibilidade ao contato com o difenciprone nos voluntários sensibilizados em áreas previamente irradiadas. RESULTADOS: A suscetibilidade à radiação UVB foi de 81,5% nos pacientes com melanoma maligno e de 31,2% no grupo-controle. O risco de um indivíduo desenvolver o melanoma maligno foi 9,7 vezes maior do que nos indivíduos UVB-resistentes. CONCLUSÕES: A UVB-suscetibilidade pode ser considerada um fator de risco importante para o desenvolvimento do melanoma maligno.BACKGROUND: It is well established that UV radiation provokes an immunological depletion in the skin, enabling the development of malignant cutaneous tumors. Most nonmelanoma skin cancer patients are considered to be UVB-susceptible. OBJECTIVE: To study the behavior of UVB- susceptibility in malignant melanoma (MM patients and whether this is a risk factor to the development of MM. METHODS: Eighty-eight volunteers were selected and divided into two groups: healthy control group (n = 61 and MM group (n = 27, which were identified according to the following clinical criteria: histopathological type, level of invasion, skin phototype, sex and age. Susceptibility to ultraviolet B (UVB radiation was measured by the onset of a contact

  7. Technology Development of Salak (Salacca Zalacca) Chips With Vacuum Frying Machine Base On Expert System In Kramat-Bangkalan Regency

    Science.gov (United States)

    Rosida, D. F.; Happyanto; Anggraeni; Sugiarto; Hapsari

    2018-01-01

    Agropolitan Program is one form of regional development to improve agribusiness system and effort to improve the welfare of the community. One of the leading commodities in Bangkalan agroclimates is salak which is a potentially very large commodity to be developed. Salak commodities in Kramat Bangkalan Indonesia have developed varous salak produced such as dates of salak, syrup and dodol salak. Salak chips was the target of innovation from processed salak. The Production of salak chips using frying technology with vacuum system to obtain crunchy chips. To get the results need to be developed synergy technology to combine the process conditions and the right system in producing good quality salak chips. Bangkalan Regency is the potential to continue to develop products using a variety of salak to the processed form of vacuum frying machine based on expert system so that the resulting product would be great texture, aroma and taste. This will make the area of Bangkalan, Indonesia be more independent in producing and increasing revenue.

  8. Shape Memory Alloy connectors for Ultra High Vacuum applications: a breakthrough for accelerator technologies

    CERN Document Server

    AUTHOR|(CDS)2091326; Garion, Cedric

    Beam-pipe coupling in particle accelerators is nowadays provided by metallic flanges that are tightly connected by several screws or heavy collars. Their installation and dismounting in radioactive areas contribute to the radiation doses received by the technical personnel. Owing to the increased proton-beam intensity and luminosity of the future High-Luminosity LHC (HL-LHC), radioactivity in some specific zones will be significantly higher than in the present LHC; the presence of the technical staff in these areas will be strictly controlled and minimized. Remote interventions are being considered, too. Shape Memory Alloys (SMAs) offer a unique possibility to generate tight connections and fast clamping/unclamping by remotely changing the temperature of the junction unit. In fact, SMAs exhibit unique strain and stress recovery capabilities which are related to reversible phase transition mechanisms, induced thermally or mechanically. In this PhD work, a novel Ultra-High Vacuum (UHV) coupling system based on ...

  9. Eco-sewerage System Design for Modern Office Buildings: based on Vacuum and Source-separation Technology

    Science.gov (United States)

    Xu, Kangning; Wang, Chengwen; Zheng, Min; Yuan, Xin

    2010-11-01

    This study aimed to construct an on-site eco-sewerage system for modern office buildings in urban area based on combined innovative technologies of vacuum and source-separation. Results showed that source-separated grey water had low concentrations of pollutants, which helped the reuse of grey water. However, the system had a low separation efficiency between the yellow water and the brown water, which was caused by the plug problem in the urine collection from the urine-diverting toilets. During the storage of yellow water for liquid fertilizer production, nearly all urea nitrogen transferred to ammonium nitrogen and about 2/3 phosphorus was lost because of the struvite precipitation. Total bacteria and coliforms increased first in the storage, but then decreased to low concentrations. The anaerobic/anoxic/aerobic MBR had high elimination rates of COD, ammonium nitrogen and total nitrogen of the brown water, which were 94.2%, 98.1% and 95.1%, respectively. However, the effluent still had high contents of colority, nitrate and phosphorus, which affected the application of the effluent for flushing water. Even though, the effluent might be used as dilution water for the yellow water fertilizer. Based on the results and the assumption of an ideal operation of the vacuum source-separation system, a future plan for on-site eco-sewerage system of modern office buildings was constructed. Its sustainability was validated by the analysis of the substances flow of water and nutrients.

  10. Removal of aluminum from drinking water treatment sludge using vacuum electrokinetic technology.

    Science.gov (United States)

    Xu, Hang; Ding, Mingmei; Shen, Kunlun; Cui, Jianfeng; Chen, Wei

    2017-04-01

    A vacuum electrokinetic apparatus was operated at a municipal water supply plant in Wuxi, China to study the removal of aluminum from the plant's drinking water treatment sludge, high in trivalent aluminum content. The effect of several experimental variables (initial pH, potential gradient, and zone in the sludge tank) and the trivalent aluminum removal mechanism were analyzed. The speciation of trivalent aluminum mainly depends on the initial pH of drinking water treatment sludge, and more fractions of trivalent aluminum were migrated at pH 4 than at higher or lower pH. The application of high voltage can enhance the removal efficiency of aluminum. A three-dimensional electric field analysis explained the difference in the removal efficiency at different zones in the sludge tank. In view of energy consumption, when the initial pH was 4 and a potential gradient of 2 V cm -1 was applied, achieving a final aluminum concentration of 30 g kg -1 after 120 h. The specific energy consumption was 11.7 kWh kg -1 of Al removed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. (UVB)-induced DNA damage

    African Journals Online (AJOL)

    Jane

    2011-08-17

    Aug 17, 2011 ... E-mail: renu2498@hotmail.com. Abbreviations: POE, Pandanus ordoratissimus extract; KSCs, keratinocyte stem cells; AAG, ascorbyl glucoside. as the major cause of human skin cancer. It is well established that UVB induced DNA damage by photoi- somerization, resulting in the formation of the 6-4 photo-.

  12. Vacuum extraction

    DEFF Research Database (Denmark)

    Nielsen, Mathilde Maagaard; Oestergaard, Jeanett; Johansen, Marianne

    2012-01-01

    Objectives. To develop and validate an Objective Structured Assessment of Technical Skills (OSATS) scale for vacuum extraction. Design. Two part study design: Primarily, development of a procedure-specific checklist for vacuum extraction. Hereafter, validationof the developed OSATS scale for vacuum...... with daily work in the obstetric field were tested. Methods. The Delphi method was used for development of the scale. In a simulated vacuum extraction scenario first-year residents and obstetric chief physicians were rated using the developed OSATS scale for vacuum extraction to test construct validity...... scale for vacuum extraction is a reliable test for differentiating between competence levels in a simulated setting....

  13. Production Technology of Holographic Diffraction Gratings Based on Inorganic Vacuum Photoresists

    Directory of Open Access Journals (Sweden)

    Dan’ko, V.A.

    2014-09-01

    Full Text Available An innovative project on development of the technological method for holographic diffraction gratings production which allows to produce high-quality diffractive elements with spatial frequencies from 600 to 3600 mm–1 for spectral instruments have been carried out. The technological instructions for the implementation of this method have been developed and experimental samples are produced. It was established that the characteristics of experimental samples of the holographic diffraction gratings produced under this project meet the specifications and the state standard 3-6128-86.

  14. Indian Vacuum Society: The Indian Vacuum Society

    Science.gov (United States)

    Saha, T. K.

    2008-03-01

    The Indian Vacuum Society (IVS) was established in 1970. It has over 800 members including many from Industry and R & D Institutions spread throughout India. The society has an active chapter at Kolkata. The society was formed with the main aim to promote, encourage and develop the growth of Vacuum Science, Techniques and Applications in India. In order to achieve this aim it has conducted a number of short term courses at graduate and technician levels on vacuum science and technology on topics ranging from low vacuum to ultrahigh vacuum So far it has conducted 39 such courses at different parts of the country and imparted training to more than 1200 persons in the field. Some of these courses were in-plant training courses conducted on the premises of the establishment and designed to take care of the special needs of the establishment. IVS also regularly conducts national and international seminars and symposia on vacuum science and technology with special emphasis on some theme related to applications of vacuum. A large number of delegates from all over India take part in the deliberations of such seminars and symposia and present their work. IVS also arranges technical visits to different industries and research institutes. The society also helped in the UNESCO sponsored post-graduate level courses in vacuum science, technology and applications conducted by Mumbai University. The society has also designed a certificate and diploma course for graduate level students studying vacuum science and technology and has submitted a syllabus to the academic council of the University of Mumbai for their approval, we hope that some colleges affiliated to the university will start this course from the coming academic year. IVS extended its support in standardizing many of the vacuum instruments and played a vital role in helping to set up a Regional Testing Centre along with BARC. As part of the development of vacuum education, the society arranges the participation of

  15. Vacuum system

    OpenAIRE

    Gröbner, Oswald

    2006-01-01

    The vacuum system of a particle accelerator must provide the necessary conditions for the high energy beam to avoid loss of particles and deterioration of the beam quality. In this talk we will review basic design concepts, vacuum components and procedures required for an accelerator vacuum system.

  16. UVB: suscetibilidade no melanoma maligno

    OpenAIRE

    Nasser,Nilton

    2010-01-01

    FUNDAMENTOS: Está bem definido que a radiação ultravioleta provoca depleção imunológica na pele, permitindo o desenvolvimento de tumores cutâneos malignos. A maioria dos pacientes de cânceres da pele não melanomas são considerados UVB-suscetíveis. OBJETIVOS: Estudar a UVB-suscetibilidade nos pacientes com melanoma maligno e se este é um fator de risco para o desenvolvimento desse câncer. MÉTODOS: Foram selecionados 88 voluntários divididos em dois grupos: grupo-controle saudável (n=61) e grup...

  17. New trends in oil free vacuum generation equipment

    Directory of Open Access Journals (Sweden)

    Vasiliev Yu. K.

    2010-03-01

    Full Text Available Main modern trends of vacuum technology and vacuum equipment market such as fore-vacuum and high-vacuum pumps, analytical devices and vacuum components are shown. Amount of different regional markets is also reviewed by main world vacuum equipment suppliers turnover.

  18. Power vacuum tubes handbook

    CERN Document Server

    Whitaker, Jerry

    2012-01-01

    Providing examples of applications, Power Vacuum Tubes Handbook, Third Edition examines the underlying technology of each type of power vacuum tube device in common use today. The author presents basic principles, reports on new development efforts, and discusses implementation and maintenance considerations. Supporting mathematical equations and extensive technical illustrations and schematic diagrams help readers understand the material. Translate Principles into Specific Applications This one-stop reference is a hands-on guide for engineering personnel involved in the design, specification,

  19. Vacuum pumping concepts for ETF

    International Nuclear Information System (INIS)

    Homeyer, W.G.

    1980-09-01

    The Engineering Test Facility (ETF) poses unique vacuum pumping requirements due to its large size and long burn characteristics. These requirements include torus vacuum pumping initially and between burns and pumping of neutralized gas from divertor collector chambers. It was found that the requirements could be met by compound cryopumps in which molecular sieve 5A is used as the cryosorbent. The pumps, ducts, and vacuum valves required are large but fit with other ETF components and do not require major advances in vacuum pumping technology. Several additional design, analytical, and experimental studies were identified as needed to optimize designs and provide better design definition for the ETF vacuum pumping systems

  20. VACUUM TRAP

    Science.gov (United States)

    Gordon, H.S.

    1959-09-15

    An improved adsorption vacuum trap for use in vacuum systems was designed. The distinguishing feature is the placement of a plurality of torsionally deformed metallic fins within a vacuum jacket extending from the walls to the central axis so that substantially all gas molecules pass through the jacket will impinge upon the fin surfaces. T fins are heated by direct metallic conduction, thereby ol taining a uniform temperature at the adeorbing surfaces so that essentially all of the condensible impurities from the evacuating gas are removed from the vacuum system.

  1. High-power UV-B LEDs with long lifetime

    Science.gov (United States)

    Rass, Jens; Kolbe, Tim; Lobo-Ploch, Neysha; Wernicke, Tim; Mehnke, Frank; Kuhn, Christian; Enslin, Johannes; Guttmann, Martin; Reich, Christoph; Mogilatenko, Anna; Glaab, Johannes; Stoelmacker, Christoph; Lapeyrade, Mickael; Einfeldt, Sven; Weyers, Markus; Kneissl, Michael

    2015-03-01

    UV light emitters in the UV-B spectral range between 280 nm and 320 nm are of great interest for applications such as phototherapy, gas sensing, plant growth lighting, and UV curing. In this paper we present high power UV-B LEDs grown by MOVPE on sapphire substrates. By optimizing the heterostructure design, growth parameters and processing technologies, significant progress was achieved with respect to internal efficiency, injection efficiency and light extraction. LED chips emitting at 310 nm with maximum output powers of up to 18 mW have been realized. Lifetime measurements show approximately 20% decrease in emission power after 1,000 operating hours at 100 mA and 5 mW output power and less than 30% after 3,500 hours of operation, thus indicating an L50 lifetime beyond 10,000 hours.

  2. Gases and vacua handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 1: Gases and Vacua provides information on the many aspects of vacuum technology, from material on the quantum theoretical aspects of the complex semi-conductors used for thermionic and photo-electric emission to data on the performance of commercially available pumps, gauges, and high-vacuum materials. The handbook satisfies the need of workers using vacuum apparatuses or works on the diverse applications of high-vacuum technology in research and industry. The book is a compilation of long articles prepared by experts in vacuum technology. Sufficient theoret

  3. The Use of the Molecular Adsorber Coating Technology to Mitigate Vacuum Chamber Contamination During Pathfinder Testing for the James Webb Space Telescope

    Science.gov (United States)

    Abraham, Nithin S.; Hasegawa, Mark M.; Wooldridge, Eve M.; Henderson-Nelson, Kelly A.

    2016-01-01

    As a coating made of highly porous zeolite materials, the Molecular Adsorber Coating (MAC) was developed to capture outgassed molecular contaminants, such as hydrocarbons and silicones. For spaceflight applications, the adsorptive capabilities of the coating can alleviate on-orbit outgassing concerns on or near sensitive surfaces and instruments within the spacecraft. Similarly, this sprayable paint technology has proven to be significantly beneficial for ground based space applications, in particular, for vacuum chamber environments. This paper describes the recent use of the MAC technology during Pathfinder testing of the Optical Ground Support Equipment (OGSE) for the James Webb Space Telescope (JWST) at NASA Johnson Space Center (JSC). The coating was used as a mitigation tool to entrap persistent outgassed contaminants, specifically silicone based diffusion pump oil, from within JSC's cryogenic optical vacuum chamber test facility called Chamber A. This paper summarizes the sample fabrication, installation, laboratory testing, post-test chemical analysis results, and future plans for the MAC technology, which was effectively used to protect the JWST test equipment from vacuum chamber contamination.

  4. LCD plus NB-UVB reduces time to improvement of psoriasis vs. NB-UVB alone.

    Science.gov (United States)

    Bagel, Jerry

    2009-04-01

    Use of coal tar with narrowband (NB) ultraviolet B (UVB) light (the Goeckerman regimen) is an effective treatment for plaque psoriasis that has become impractical in outpatient care mainly due to the inconvenience and aesthetic concerns of coal tar. This study evaluated the safety, efficacy, and convenience of adding a novel LCD (coal tar) solution to standard NB-UVB phototherapy in adults with chronic plaque psoriasis. Patients applied LCD solution to half-body twice daily at home and received outpatient full-body NB-UVB light therapy 3 times a week for up to 12 weeks. A blinded investigator graded psoriasis severity of body halves and bilateral target lesions and monitored adverse reactions. Patients rated their psoriasis symptoms and LCD solution aesthetics. NB-UVB + LCD therapy reduced the median time to clearance or minimal disease in at least 50% of the population by 3 weeks (4 weeks with NB-UVB + LCD versus 7 weeks with NB-UVB alone). A statistically superior clinical response was observed by the end of week 4 with NB-UVB + LCD versus NB-UVB alone (P LCD solution into outpatient NB-UVB light therapy is safe, convenient, effective, and can improve psoriasis more quickly than NB-UVB light therapy alone.

  5. Characterization of specific spoilage organisms (SSOs) in vacuum-packed ham by culture-plating techniques and MiSeq next-generation sequencing technologies.

    Science.gov (United States)

    Piotrowska-Cyplik, Agnieszka; Myszka, Kamila; Czarny, Jakub; Ratajczak, Katarzyna; Kowalski, Ryszard; Biegańska-Marecik, Róża; Staninska-Pięta, Justyna; Nowak, Jacek; Cyplik, Paweł

    2017-01-01

    Knowledge regarding microaerophilic and anaerobic specific spoilage organisms (SSOs) is crucial for an appropriate evaluation of vacuum-packed ham. The objective of this study was to characterize the SSO community in vacuum-packed ham by a culture-dependent technique and MiSeq next-generation sequencing (NGS) platform. The relation between changes among the SSO group in the ham and changes in sensory characteristics of the product was also assessed. In the study, conventional microbiological analyses were employed in order to establish the participation of several groups of microorganisms in the deterioration of vacuum-packed ham. The diversity of the SSO group in the product was further assessed with the use of MiSeq NGS technology. The bacteria identified in sliced cooked ham belonged mostly to four phyla, namely Actinobacteria, Proteobacteria, Firmicutes and Bacteroidetes. A temperature of 4 °C favoured the development of mesophilic and psychrophilic/psychrotrophic flora, mainly Lactobacillaceae, Enterobacteriaceae and Micrococcaceae families. A high ratio of Brochothrix thermosphacta species and new, cold-tolerant Clostridium spp. was also observed. The growth of these microorganisms facilitated changes in the pH value and organoleptic characteristics of the product. This study confirms that the combination of culturing and MiSeq NGS technology improves the microbial evaluation of food. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  6. 20 January 2014 - Members of the Regional Assemblies and Parliaments United Kingdom of Great Britain and Northern Ireland visiting the LHC tunnel at Point 8 with Technology Department, Vacuum, Surfaces and Coatings Group P. Cruikshank.

    CERN Document Server

    Pantelia, Anna

    2014-01-01

    20 January 2014 - Members of the Regional Assemblies and Parliaments United Kingdom of Great Britain and Northern Ireland visiting the LHC tunnel at Point 8 with Technology Department, Vacuum, Surfaces and Coatings Group P. Cruikshank.

  7. Vacuum II

    CERN Document Server

    Franchetti, G

    2013-01-01

    This paper continues the presentation of pumps begun in ‘Vacuum I’. The main topic here is gauges and partial-pressure measurements. Starting from the kinetics of gases, the various strategies for measuring vacuum pressures are presented at an introductory level, with some reference to hardware devices. Partial-pressure measurement techniques are introduced, showing that the principles of ion selection have a direct similarity to particle dynamics in accelerators.

  8. Decay of bound states in the continuum of Majorana fermions induced by vacuum fluctuations: Proposal of qubit technology

    Science.gov (United States)

    Ricco, L. S.; Marques, Y.; Dessotti, F. A.; Machado, R. S.; de Souza, M.; Seridonio, A. C.

    2016-04-01

    We report on a theoretical investigation of the interplay between vacuum fluctuations, Majorana quasiparticles (MQPs), and bound states in the continuum (BICs) by proposing a new venue for qubit storage. BICs emerge due to quantum interference processes as the Fano effect and, since such a mechanism is unbalanced, these states decay as regular into the continuum. Such fingerprints identify BICs in graphene as we have discussed in detail in Phys. Rev. B 92, 245107 (2015), 10.1103/PhysRevB.92.245107 and Phys. Rev. B, 92, 045409 (2015), 10.1103/PhysRevB.92.045409. Here, by considering two semi-infinite Kitaev chains within the topological phase, coupled to a quantum dot (QD) hybridized with leads, we show the emergence of a novel type of BICs, in which MQPs are trapped. As the MQPs of these chains far apart build a delocalized fermion and qubit, we identify that the decay of these BICs is not connected to Fano and it occurs when finite fluctuations are observed in the vacuum composed by electron pairs for this qubit. From the experimental point of view, we also show that vacuum fluctuations can be induced just by changing the chain-dot couplings from symmetric to asymmetric. Hence, we show how to perform the qubit storage within two delocalized BICs of MQPs and to access it when the vacuum fluctuates by means of a complete controllable way in quantum transport experiments.

  9. Mean Annual UV-B Irradiance

    Data.gov (United States)

    U.S. Environmental Protection Agency — Ultraviolet-B (UV-B) radiation is the most energetic part of sunlight reaching the Earth's surface (wavelength region is 280 to 315 nm), and it has been shown to...

  10. UVB radiation and New Zealand agriculture

    International Nuclear Information System (INIS)

    Laing, W.

    1993-01-01

    UV has variable effects on plant growth and yields. Over 300 species have been screened for UVB sensitivity, and over half showed sensitivity. In some cases, UV has been shown to reduce yields of some varieties while having little effect or even increasing the yields of others. These experiments included a wide variety of important crop plants (eg wheat, soybean, trees, (conifers) etc). The data show that selective breeding might be used to improve UVB tolerance of various important species. (author)

  11. Vacuum evaporation, a technology for re-using water and reducing waste; La evaporacion al vacio una tecnologia para la reduccion de residuos y reutilizacion del agua

    Energy Technology Data Exchange (ETDEWEB)

    Casas, O.; Sabate, E.; Casas, F.; Lopez, J.

    2009-07-01

    In order to improve companies sustain ability and environmental commitment, we have developed a concentration technology for reducing the volume of industrial waste water at low energy cost and recovering the water for various applications. The advantages of this system are recovery of the water, minimum maintenance without reagents and compactness with any type of waste water. Industrials Titan represents and example of the recycling of water by means of vacuum evaporation to solve a double problem: the conductivity of the water from the decalcified and the COD of the water from the painting process. (Author)

  12. ITER articulated inspection arm (AIA): R and D progress on vacuum and temperature technology for remote handling

    Energy Technology Data Exchange (ETDEWEB)

    Perrot, Y.; Friconneau, J.P. [Robotics and Interactive Systems Unit - CEA/LIST, 92 - Fontenay aux Roses (France); Cordier, J.J.; Gargiulo, L. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Palmer, J.D. [EFDA CSU Garching (Germany); Martin, E. [ITER International Team, Garching (Germany); Tesini, A. [ITER International Team, ITER Naka Joint Work Site, Iberaki-ken (Japan)

    2004-07-01

    To perform an intervention a short time after plasma shutdown, the operation of the robot will have to be under ITER conditions which means: under high vacuum, pollution avoidance and a temperature ambience around 120 C. The feasibility studies have led to the design of a robot in the shape of a 8.2 meter long articulated arm made up of 5 modules with 11 articulated joints. A single module prototype has been manufactured to be tested. The prototype was set up in a specific vacuum vessel at Tore-Supra facility that can be baked up to 230 C under high-vacuum conditions. The first tests have shown that: -) the efficiency of the actuators at 120 C was the same than in air at room temperature, the speed was slightly lower, -) the monitoring of the temperature of the motor and of the power electronics components showed an increasing of only 40 C during 3 full pitch movements, and -) most of the greases was degassed during the 1 week long baking at 200 C except one which comes from an organic material in a component that has to be identified.

  13. Handbook of vacuum physics

    CERN Document Server

    1964-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is a handbook of vacuum physics, with emphasis on the properties of miscellaneous materials such as mica, oils, greases, waxes, and rubber. Accurate modern tables of physical constants, properties of materials, laboratory techniques, and properties of commercial pumps, gauges, and leak detectors are presented. This volume is comprised of 12 chapters and begins with a discussion on pump oils, divided into rotary pump oils and vapor pump oils. The next chapter deals with the properties and applications of greases, including outgassing and vapor pr

  14. Vacuum Valve

    CERN Multimedia

    1974-01-01

    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  15. Narrowband UVB phototherapy for small plaque parapsoriasis.

    Science.gov (United States)

    Aydogan, K; Karadogan, S K; Tunali, S; Adim, S B; Ozcelik, T

    2006-05-01

    Narrowband UVB (NB-UVB) phototherapy has been shown to be effective for the treatment of various dermatoses. To analyze the effects of NB-UVB phototherapy for small plaque parapsoriasis (SPP). The response of 45 patients (24 females, 21 males, age range 20-58 years) with histologically confirmed SPP were assessed. NB-UVB therapy was given 3-4 times weekly. The initial treatment dose was 70% of the minimal erythema dose. The doses were increased gradually with a standard increment of 20/10/0. Clinical response was determined as follows: complete response (CR), at least 90% clearing of skin lesions; partial response (PR), at least 50% but less than 90% clearing and no response (NR), less than 50% clearing. The follow-up period was 6-24 months after the treatment. NB-UVB treatment led to CR in 33 of 45 patients (73.3%) with a mean cumulative dose of 14.3 J/cm(2) (range 3.2-24.1 J/cm(2)) after a mean number of 29 exposures (range 16-51 sessions); PR in 12 of 45 (26.6%) with a cumulative dose of 15.6 J/cm(2) (range 10.4-23.3 J/cm(2)) after a mean number of 29.4 exposures (range 25-50 sessions). Nineteen patients with CR had skin phototype II, 13 had type III and 1 had type I. Among the patients with PR, 7 had skin phototype II and 5 had type III. Postinflammatory hyperpigmentation was observed in 51% of the patients. Relapses occurred in six patients within a mean time of 7.5 months (2-12 months). NB-UVB phototherapy has several advantages over treatment with broadband UVB and PUVA. NB-UVB therapy for patients with SPP is an effective, safe and practical alternative treatment modality. Further larger studies with longer follow-up periods are necessary to determine the proper clinical response and long-term complications of NB-UVB therapy in this disease.

  16. Vacuum System at IUAC

    Science.gov (United States)

    Mandal, A.

    2012-11-01

    Vacuum technology is an integral part of any accelerator system. At IUAC we have a 15UD PELLETRON, superconduting LINAC, Low Energy Ion beam Facility and a 1.7MV pelletron. Vacuum requirement in these accelerators is ~10-8 torr. Various types of Vacuum pump are used in different zones of the accelerators depending on load. Since the whole accelerator is quite long, distributed pumps are placed in different sections as per load. In ion sources displacement type pump viz turbo-pumps are usually used as the gas load is quite high. In other parts of the accelerator combination of getter and ion pumps are used. It is very much necessary to isolate different sections for maintenance purpose. Proper valves are used to isolate the sections and to avoid vacuum accidents proper interlock system is introduced. If air goes in some sections accidentally, valves will close automatically to protect other sections. The talk will cover different types of pumps and interlock used in accelerators at IUAC.

  17. Experimental tests a technological demonstrator of extraction of tritium for Pb loop systems (15.7) Li of the TBM of ITER by permeation against vacuum

    International Nuclear Information System (INIS)

    Sacritan, R.; Bonjoch, I.; Veredas, G.; Ibarra, A.

    2013-01-01

    Shortages and wasteful production of tritium, one of the necessary fuel in nuclear fusion, is putting into question the self-sufficiency of this type of energy. For this reason, the rapid recovery of tritium is a key milestone in the field of r and d for the development of efficient technologies that are able to recover the tritium generated in the loops of liquid metal reactors such as ITER fusion for reuse as fuel, thus increasing its efficiency. Once designed and manufactured a demonstrator based on a loop of liquid Pb-Li on a small scale, and equipped with high flexibility to modify process variables, the objective of this study is the realization of many experimental trials that allow quantifying the efficiency in the recovery of H 2 of loop under different conditions through the permeation against vacuum, and thus to assess the possible application for the extraction of tritium in future fusion reactors.

  18. Comparison of UV-B measurements performed with a Brewer spectrophotometer and a new UVB-1 broad band detector

    Science.gov (United States)

    Bais, Alkiviadis F.; Zerefos, Christos S.; Meleti, Charicleia; Ziomas, Ioannis C.

    1994-01-01

    Measurements of the UV-B erythemal dose, based on solar spectra acquired with a Brewer spectrophotometer at Thessaloniki, Greece, are compared to measurements performed with the recently introduced, by the Yankee Environmental Systems, (Robertson type) broad band solar UV-B detector. The spectral response function of this detector, when applied to the Brewer spectral UV-B measurements, results in remarkably comparable estimates of the erythemal UV-B dose. The two instruments provide similar information on the UV-B dose when they are cross-examined under a variety of meteorological and atmospheric conditions and over the a large range of solar zenith angles and total ozone.

  19. Vacuum production; Produccion de vacio

    Energy Technology Data Exchange (ETDEWEB)

    Segovia, J. L. de

    2010-07-01

    Since the advent of ultra high vacuum in 1958 has been a great demand for new as means of production and to meet the process needs to be done: industry heavy, high technology and space research areas, large accelerator systems particles or nuclear fusion. In this paper we explore the modern media production: dry vacuum pumps, turbo pumps, pump status diffusion ion pumps and cryopumps. (Author)

  20. High productivity vacuum blasting system

    International Nuclear Information System (INIS)

    Ebadian, M.A.

    2000-01-01

    The purpose of the project is to increase the productivity and economics of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCB's and lead-base paint and provides worker and environmental protection by continuously recycling the blast media and the full containment of the dust generated in the process

  1. Vacuum microelectronics

    International Nuclear Information System (INIS)

    Grayer, G.H.

    1990-10-01

    The last few years have seen references in scientific and economic literature to research and development taking place on ''vacuum microelectronics'', but few in the particle physics community seem to know more than these brief, second hand reports, mostly written for a non-scientific readership. The interest of these devices for the particle physics community is obvious when it is realised that one of the driving forces for this research and development is the military need for electronic components which can withstand very high doses of radiation. The author therefore arranged to visit one of the centres of research on these components, and the information obtained there formed the principle source material for this summary. (author)

  2. Investigation of several dynamic processes on solid surfaces and its application to the extreme high vacuum technology. Kotai hyomenjo no doteki katei no kaimei to sono goku koshinku gijutsu eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, D.; Honma, T. (The Univ. of Tokyo, Tokyo (Japan). Inst. of Industrial Science)

    1991-08-26

    This paper makes fundamental studies on several dynamic processes on solid surfaces such as adsorption, desorption, surface segregation, surface precipitation and initial oxidation. The studies aim at applying the information and knowledge obtained to development of an extreme high vacuum technology. Theoretical and technological consideration is given to quantification and precision of surface analytical methods necessary and indispensable for a base technology for the study. The paper pays particular attention to the following three surface analytical methods: Auger electron spectroscopy for a composition analysis, surface extended electron energy loss fine strucutre as a surface short-distance order structural analysis, and thermal sesorption spectroscopy as an adsorption/desorption process analysis. These methods are applied to fundamental studies for development of materials required for creation of an extreme high vacuum. Taking an outgassing phenomenon in the extreme high vacuum as a set of various dynamic processes, quantitative measurement and a mechanism analysis of outgassing are conducted. Actually, the extreme high vacuum is trially produced. 244 refs., 128 figs., 21 tabs.

  3. Vacuum Frying: A nutritional approach

    Directory of Open Access Journals (Sweden)

    Manuel Coronel

    2014-09-01

    Full Text Available (Received: 2014/08/07 - Accepted: 2014/09/22One of the largest areas of the food industry is the production of snacks, but these have generally an inadequate nutritional profile in healthy eating. The vacuum frying technology is presented as a clear option processing for the development of new products and existing ones. This review article presents the advantages of using technology in Vacuum frying different types of food, especially in relation to the contents of some micronutrients and fat. They also mention the work done in Ecuador, especially in local products.

  4. Experimental skin carcinoma by UVB application

    Directory of Open Access Journals (Sweden)

    Andrada Iftode

    2016-12-01

    Full Text Available OBJECTIVES AND BACKGROUND The aim of this research study was to evaluate the harmful effects at skin level induced by concomitant and repeated exposure to three toxic agents: UVB radiation, DMBA and TPA. MATERIALS AND METHODS Experimental mice were divided in thw following groups (n=5 mice/group: group 1 – healthy mice, group 2 – mice exposed to UVB – radiation and topical administration of acetone and group 3 – mice exposed to UVB – radiation and topical application of DMBA and TPA solutions (phase I - double tumor initiation and phase II - tumor promotion. RESULTS Application of these compounds led to the development of skin papilloma and to significant changes in skin parameters. CONCLUSIONS The barrier function of the skin was degraded in UVB exposed mice. DMBA and TPA depended on carcinogens schedule and corelated with skin carcinoma. Graphical abstract: Schematic protocol of experimental skin carcinoma REFERENCES 1. Lee Ja, Ko Jh, Jung Bg, Kim Th, Hong Ji, Park Ys, Lee Bj. Fermented Prunus mume with Probiotics Inhibits 7,12- Dimethylbenz[a]anthracene and 12-OTetradecanoyl phorbol-13-acetate Induced Skin Carcinogenesis through Alleviation of Oxidative Stress. Asian Pac J Cancer Prev. 2013;14:2973-2978. 2. Firooz A, Sadr B, Babakoohi S, Sarraf-Yazdy M, Fanian F, Kazerouni-Timsar A, NassiriKashani M, Naghizadeh MM, Dowlati Y. Variation of Biophysical Parameters of the Skin with Age, Gender, and Body Region. Scientific World Journal. 2012; doi.org/10.1100/2012/386936 3. Gheorgheosu (Coricovac D, Borcan F, Balasz NI, Soica C, Simu G, Kemeny L, Dehelean CA. Evaluation of skin parameters in C57BL/6J mice exposed to chemical and environmental factors using non-invasive methods. J Agroalim Proc Technol. 2014;20:14-20.

  5. Quercitrin protects skin from UVB-induced oxidative damage

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Yuanqin [Cancer Institute, The First Affiliated Hospital, China Medical University, Shenyang (China); Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States); Li, Wenqi; Son, Young-Ok; Sun, Lijuan; Lu, Jian; Kim, Donghern; Wang, Xin [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States); Yao, Hua [Department of Stomatology, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang (China); Wang, Lei; Pratheeshkumar, Poyil; Hitron, Andrew J. [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States); Luo, Jia [Department of Internal Medicine, University of Kentucky, 800 Rose Street, Lexington, KY (United States); Gao, Ning [Department of Pharmacognos, College of Pharmacy, 3rd Military Medical University, Chongqing (China); Shi, Xianglin [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States); Zhang, Zhuo, E-mail: zhuo.zhang@uky.edu [Graduate Center for Toxicology, University of Kentucky, 1095 VA Drive, Lexington, KY (United States)

    2013-06-01

    Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin. - Highlights: • Oxidative stress plays a key role in UV-induced cell and tissue injuries. • Quercitrin decreases ROS generation and restores antioxidants irradiated by UVB. • Quercitrin reduces UVB-irradiated oxidative DNA damage, apoptosis, and inflammation. • Quercitrin functions as an antioxidant against UVB-induced skin injuries.

  6. UV-B radiation and acclimation in timberline plants

    International Nuclear Information System (INIS)

    Turunen, Minna; Latola, Kirsi

    2005-01-01

    Research has shown that some plants respond to enhanced UV-B radiation by producing smaller and thicker leaves, by increasing the thickness of epidermis and concentration of UV-B absorbing compounds of their surface layers and activation of the antioxidant defence system. The response of high-altitude plants to UV-B radiation in controlled conditions is often less pronounced compared to low-altitude plants, which shows that the alpine timberline plants are adapted to UV-B. These plants may have a simultaneous co-tolerance for several stress factors: acclimation or adaptation to the harsh climate can also increase tolerance to UV-B radiation, and vice versa. On the other hand, alpine timberline plants of northern latitudes may be less protected against increasing UV-B radiation than plants from more southern latitudes and higher elevations due to harsh conditions and weaker preadaptation resulting from lower UV-B radiation exposure. It is evident that more long-term experimental field research is needed in order to study the interaction of climate, soil and UV-B irradiance on the timberline plants. - More long-term field research is needed to assess the interaction of climate, soil and UV-B on timberline plants

  7. Vacuum system for ISABELLE

    International Nuclear Information System (INIS)

    Hobson, J.P.

    1975-01-01

    An analysis is presented of the proposed vacuum system for the planned ISABELLE storage rings with respect to acceptability and practicality from the vacuum viewport. A comparison is made between the proposed vacuum system and the vacuum system at the CERN ISR, and some comments on various design and operational parameters are made

  8. Mechanisms of caffeine-induced inhibition of UVB carcinogenesis

    Directory of Open Access Journals (Sweden)

    Allan H Conney

    2013-06-01

    Full Text Available Sunlight-induced nonmelanoma skin cancer is the most prevalent cancer in the United States with more than 2 million cases per year. Several studies have shown an inhibitory effect of caffeine administration on UVB-induced skin cancer in mice, and these studies are paralleled by epidemiology studies that indicate an inhibitory effect of coffee drinking on nonmelanoma skin cancer in humans. Strikingly, decaffeinated coffee consumption had no such inhibitory effect.Mechanism studies indicate that caffeine has a sunscreen effect that inhibits UVB-induced formation of thymine dimers and sunburn lesions in the epidermis of mice. In addition, caffeine administration has a biological effect that enhances UVB-induced apoptosis thereby enhancing the elimination of damaged precancerous cells, and caffeine administration also enhances apoptosis in tumors. Caffeine administration enhances UVB-induced apoptosis by p53-dependent and p53-independent mechanisms. Exploration of the p53-independent effect indicated that caffeine administration enhanced UVB-induced apoptosis by inhibiting the UVB-induced increase in ATR-mediated formation of phospho-Chk1 (Ser345 and abolishing the UVB-induced decrease in cyclin B1 which resulted in caffeine-induced premature and lethal mitosis in mouse skin. In studies with cultured primary human keratinocytes, inhibition of ATR with siRNA against ATR inhibited Chk1 phosphorylation and enhanced UVB-induced apoptosis. Transgenic mice with decreased epidermal ATR function that were irradiated chronically with UVB had 69% fewer tumors at the end of the study compared with irradiated littermate controls with normal ATR function. These results, which indicate that genetic inhibition of ATR (like pharmacologic inhibition of ATR via caffeine inhibits UVB-induced carcinogenesis and supports the concept that ATR-mediated phosphorylation of Chk1 is an important target for caffeine’s inhibitory effect on UVB-induced carcinogenesis.

  9. Vacuum engineering, calculations, formulas, and solved exercises

    CERN Document Server

    Berman, Armand

    1992-01-01

    This book was written with two main objectives in mind-to summarize and organize the vast material of vacuum technology in sets of useful formulas, and to provide a collection of worked out exercises showing how to use these formulas for solving technological problems. It is an ideal reference source for those with little time to devote to a full mathematical treatment of the many problems issued in vacuum practice, but who have a working knowledge of the essentials of vacuum technology, elementary physics, and mathematics. This time saving book employs a problem-solving approach throughout, p

  10. Effects of prolonged UV-B exposure in plants

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-29

    Dec 29, 2008 ... is the differential production of pigments, especially flavonoids (Fohnmeyer et al., 1997; Musil, 1996). This type of response involves the stimulation of expression of particular genes by UV-B, implying specific UV-B light detection systems and signal transduction processes, which lead to the regulation of ...

  11. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    International Nuclear Information System (INIS)

    McPhee, William S.

    2001-01-01

    The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites

  12. Ambient UV-B radiation causes deformities in amphibian embryos

    Science.gov (United States)

    Blaustein, A.R.; Kiesecker, J.M.; Chivers, D.P.; Anthony, R.G.

    1997-01-01

    There has been a great deal of recent attention on the suspected increase in amphibian deformities. However, most reports of amphibian deformities have been anecdotal, and no experiments in the field under natural conditions have been performed to investigate this phenomenon. Under laboratory conditions, a variety of agents can induce deformities in amphibians. We investigated one of these agents, UV-B radiation, in field experiments, as a cause for amphibian deformities. We monitored hatching success and development in long-toed salamanders under UV-B shields and in regimes that allowed UV-B radiation. Embryos under UV-B shields had a significantly higher hatching rate and fewer deformities, and developed more quickly than those exposed to UV-B. Deformities may contribute directly to embryo mortality, and they may affect an individual's subsequent survival after hatching.

  13. Ahşap Kurutmada Çevre Dostu bir Teknoloji : Yüksek Frekans / High-Frequency-Vacuum Wood Drying Technology

    Directory of Open Access Journals (Sweden)

    Cengiz Güler

    2012-12-01

    Full Text Available Katma değerli olmasına karşın kurutulması güç ağaç türlerine ait kalın kerestelerin, klasik kurutma metoduyla çok uzun sürelerde kurutulabilmesi ve istenen kalite düzeylerinin tam olarak elde edilememesi nedeniyle günümüzde Yüksek Frekans-Vakum kombinasyonlu kurutma metodu (YFV kendini göstermiş durumdadır. Geçmişte özellikle yatırım maliyetleri ve teknolojik altyapı zorlukları nedeniyle yaygınlaşamayan bu yöntem tekrar güncel hale gelmiştir. Bu kurutma metodunda prensip; ısı kaynağının, elektrik enerjisi olmasıdır. Dolayısı ile katı ve sıvı yakıta göre çevre dostu olduğu kabul edilebilir. Bu metot ile ağaç malzemeye gönderilen elektromanyetik dalgaların meydana getirdiği ısıdan yararlanmak suretiyle, kalın ve güç kuruyan, başlangıç nemi yüksek olan ağaç türlerinin %10 un altındaki sonuç nemlerine kadar çok kısa sürelerde kurutulması amaçlanmaktadır. Bu çalışmada öncelikle kurutma teknoloji hakkında genel bilgi verilmiştir. Daha sonra ise, günümüze kadar yapılan orijinal çalışmalar özetlenerek klasik yöntemle kurutulmasında önemli zorluklar olan, kurutma süresi çok uzun olan veya hiç kurutulamayan Meşe, Ceviz, Kayın, İroko, Kestane gibi ağaç türlerinin kalın kerestelerinin kurutulması denemelerinden elde edilen sonuçlar ortaya konulmuştur. Son bölümde ise elde edilen bu sonuçlar özellikle metodun donanım ve işletme giderleri, ortaya çıkan kurutma süreleri ve kalite düzeyleri, çevreye uyumlu teknoloji ekseninde ele alınmıştır. Ayrıca, bu metodun kereste kurutma dışında diğer tarımsal ürün ve atıkların kurutulmasında kullanılabilir olması nedeniyle çevreye uyumlu üretim ve geri dönüşüme sağladığı katkı da bu kapsamda irdelenmiştir. High-Frequency-Vacuum Wood Drying Technology High density wood species dried very long period’s and very low quality levels with method in conventional drying. So High

  14. Progress in vacuum metal extraction, refining and consolidation

    International Nuclear Information System (INIS)

    Sundaram, C.V.; Mukherjee, T.K.; Sharma, B.P.

    1973-01-01

    The unique achievements in the process metallurgy of rare metals in the past quarter century should largely be attributed to advances in vacuum technology. New standards for high purity, increasing demand for pure metals and alloys for established applications, and steady improvement in sophistication and capacity of vacuum furnaces have provided the stimulus for developing and expanding vacuum metal extraction processes, and also exploring totally new processes. The paper discusses the thermochemistry of vacuum metallurgy, carbothermic and metallothermic reduction reactions, consolidation and refining by vacuum arc melting, electron beam melting and high temperature high vacuum sintering, and ultrapurification, with special reference to the reactive and refractory metals of Group IV to VI. (author)

  15. Uji Suhu Penggorengan Keripik Nangka Pada Alat Penggorengan Vakum (Vacuum Frying) Tipe Vacuum Pump

    OpenAIRE

    Hutabarat, Lamhot

    2016-01-01

    Vacuum frying is a food processing technology that can produce healthy food without much changing it’s original nature like the taste, aroma, color and nutrients. This research was aimed at testing the frying temperature of jackfruit chips in vacuum frying (vacuum pump type). Therefore, a research had been conducted at Agricultural Engineering Laboratory, Faculty of Agriculture USU in January - February 2014 using factorial randomized block design with one factor i.e. frying temperature (75°C...

  16. Vacuum-assisted delivery

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000514.htm Vacuum-assisted delivery To use the sharing features on this page, ... through the birth canal. When is Vacuum-assisted Delivery Needed? Even after your cervix is fully dilated ( ...

  17. Recent advances of ultraviolet light technologies in water treatment

    Energy Technology Data Exchange (ETDEWEB)

    Traksel, D.; Vinnicombe, D.A.

    2001-05-01

    UV light is part of the electromagnetic spectrum, situated between X-rays and visible light, with a wavelength between 100 and 400 nm. The UV spectrum is split into a number of bands; each band is used in specific applications. UV-C and parts of UV-B band are used for disinfection purposes (between 200 and 315 nm). Vacuum UV is associated with the oxidation of organic carbon. UV disinfection technology has been around for a long time, but major advances have been made only in the last few decades. These advances include lamp manufacture technology with respect to output, wavelength spread and operating life, configuration design and monitoring. The use of specialized medium pressure lamps, as well as the combination of medium pressure and low pressure lamps has shown a number of advantages. (orig.)

  18. Risks of increased UV-B radiation: higher plants

    International Nuclear Information System (INIS)

    Rau, W.; Hofmann, H.

    1994-01-01

    The question pursued within the Bavarian climate research programme (BayFORKLIM) in the present context was as follows: Does the fact that UV-B radiation increases with growing site elevation mean that the low sensitivity of predominantly alpine plants compared with that of lowland plants is attributable to their different genetic constitution, possibly as a result of selective pressure and/or de alpine species have a greater capacity to develop protective mechanisms? Pairs and triplets of species belonging to the same genus but occuring at different site elevations were grown from seeds in a greenhouse that is, without UV-B. In order to determine their capacity to adapt to UV-B radiation, some of the plants were additionally exposed to UV-B for 5-6 weeks prior to sensitivity testing. Sensitivity was tested by exposing the plants to additional UV-B of different intensities in test chambers. Visible damage, ranging from light bronzing or yellowing to withering, served as an assessment criterion. Levels of UV-B absorbing substances (phenylpropane species, usually flavonoids) were also measured in these plants. The results obtained permit the following conclusions: The greater UV-B resistance of alpine species compared with that of lowland species of the same genus is not attributable to their genetic constitution but rather to their superior adaptability. Superior resistance is in part due to a greater accumulation of UV-B absorbing substances. Distinct differences in sensitivity between different genera could lead to population shifts within ecosystems as a result of increased UV-B radiation. (orig./KW) [de

  19. Effect of enhanced UV-B radiation on motile microorganisms

    International Nuclear Information System (INIS)

    Haeder, D.P.

    1985-02-01

    The effect of slightly increased UV-B radiation was studied in four taxonomically very different microorganisms: the gliding prokaryotic cyanobacterium, Phormidium, the unicellular green alga Cosmarium, the flagellate Euglena and the cellular slime mold Dictyostelium. UV-B doses which can be expected as a result of a slight decrease of the protective ozone layer in the stratosphere, do not kill or damage the microorganisms visibly. However, such UV-B doses impair the development, motility and photoorientation of these organisms. Due to the inhibition of these physiological important parameters the organisms cannot respond adequately to the changing factors in their environment, which prevents the survival of the populations. (orig.) [de

  20. Plasma technological effect of vacuum-arc discharge to surface of constructional materials in the presence of surface-active substances

    International Nuclear Information System (INIS)

    Arustamov, V.N.; Ashurov, Kh.B.; Kadirov, Kh. Kh.; Khudaykulov, I.Kh.

    2013-01-01

    The effect of surface-active agents, KOH, NaOH, Ba(OH)x8H 2 O and Ba(NO 2 ) 2 x2H 2 O on the mechanism of interaction of the vacuum-arc discharge to the steel surface, the specific energy consumption, plasma vacuum-arc steel sample treatment and surface roughness are considered. It is shown that the putting of the alkali solution 20% KOH and NaOH on the treated steel surface leads to the reduction of energy consumption of 1.5-2.4 times and a decrease in the surface roughness of 1.5-3.2 times. (author)

  1. HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM

    International Nuclear Information System (INIS)

    McPhee, William S.

    1999-01-01

    The objective of this project is to improve the productivity and lower the expense of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCBs, and lead-based paint and provides worker protection by continuously recycling the material and dust for the decontamination tasks. The proposed work would increase the cleaning rate and provide safe and cost-effective decontamination of the DOE sites. This work focuses on redesigning and improving existing vacuum blasting technology including blast head nozzles, ergonomic handling of the blast head by reducing its weight; brush-ring design, vacuum level regulator, efficiency of the dust separator, and operational control sensors. The redesign is expected to enhance the productivity and economy of the vacuum blasting system by at least 50% over current vacuum blasting systems. There are three phases in the project. Phase I consists of developing and testing mathematical models. Phase II consists of pre-prototype design and fabrication and pre-prototype unit testing. Phase III consists of prototype design and field verification testing. In phase I, mathematical models are developed and analyzed for the nozzle, blast head, wind curtain, and dust separator, first as individual devices and then combined as an integrated model. This allows study of respective airflow and design parameters. The Contractor shall, based on the results of the mathematical modeling studies, design experimental models of the components and test these models. In addition, the Contractor shall develop sensors to detect the relationship of the blast head to the blast surfaces and controls to minimize the dependency on an operator's skill and judgment to obtain optimum positioning, as well as real-time characterization sensors to determine as the blast head is moving the depth to which coatings must be removed, thereby improving production and minimizing waste. In phase II, the Contractor shall design and

  2. Impact of UVB irradiation on vapor exchange in plants; Auswirkungen von UVB-Strahlung auf den pflanzlichen Gaswechsel

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, H.; Huebner, C.

    1993-03-01

    Different species of Rumex - ones that are adapted to high altitudes like R. alpinus, R. alpestris, R. scutatus, ones that can exist at different altitudes like R. crispus, R. acetosella, R. conglomeratus, and ones whose habitat is the lowland, like R. maritimus, R. thyrsiflorus were exposed to different doses of UVB radiation; their vapour exchange and photosynthesis and the conductivity of the stomata and pigments were measured. During the main experiments the plants were irradiated for a longer period of time with UVB-rays in two different intensities; the above-mentioned parameters were again measured. The plants of the preliminary experiments appeared outwardly without damage even after a very high dose of UVB radiation of 34.98 kJ/Sm..2Sd. Nor were the transpiration or chlorophyll content of the three species (R. maritimus, R. scutatus, R. thyrsiflorus) reduced at this radiation dose, and flavenoid contents were not lastingly changed. Only R. scutatus increased its flavenoid content at the UVB dose of 15.742 kJ/Sm..2Sd up to the highest UVB dose. During the main experiment, R. crispus and R. maritimus exhibited enhanced photosynthesis through UVB radiation; by contrast, the photosynthesis of R. alpinus was inhibited and that of R. alpestris, R. acetosella and R. conglomeratus remained largely uninfluenced. (orig./UWA) [Deutsch] Es wurden hoehenangepasste (Rumex alpinus, Rumex alpestris, Rumex scutatus), in der Hoehenverbreitung flexible (Rumex crispus, Rumex acetosella, Rumex conglomeratus) und tieflandangepasste (Rumex maritimus, Rumex thyrsiflorus) Rumex-Arten verschiedenen UVB-Dosen ausgesetzt und der Gaswechsel, die Photosynthese, die Leitwerte der Stomata und die Pigmente erfasst. In den Hauptversuchen wurde mit zwei verschiedenen UVB-Intensitaeten ueber einen laengeren Zeitraum hinweg bestrahlt und ebenfalls die oben genannten Parameter vergleichend untersucht. Es zeigte sich, dass die Pflanzen im Vorversuch selbst bei einer sehr hohen UVB-Dosis von 34

  3. Vacuum education courses at the General Electric Company's Neutron Devices Department, St. Petersburg, Florida

    International Nuclear Information System (INIS)

    Provo, J.L.; Brown, W.C.

    1978-01-01

    Vacuum Technology has, from the beginning, played a key role in the production of the Department's products at the General Electric Company's Neutron Devices Department (GEND). Early recognition was given to the need for vacuum education and training for producing and maintaining vacuums to meet departmental objectives. The vacuum courses taught at GEND are described. These include basic Vacuum Technology, Advanced Vacuum Technology, and specialized vacuum related courses. Course offering rationale, outlines of subject matter covered and criteria for measuring effectiveness will be presented for each course. Such vacuum technology related courses have resulted in improved GEND product quality and in reducing losses and production cost. At the same time, these courses have given participating employees career motivation for fulfilling more challenging vacuum technology job related positions and have enabled them to achieve upward mobility in the Department's work force

  4. Risks of increased UV-B radiation for humans

    International Nuclear Information System (INIS)

    Przybilla, B.; Eberlein-Koenig, B.; Bergner, T.

    1994-01-01

    If not compensated in any way, depletion of the stratospheric ozone layer leads to an increase of UV-B radiation at the earth's surface, especially towards the short-wave range, which is biologically the more active. The most concerning effect here is that of UV-B induced skin reactions, in particular malignant skintumors (malignant melanoma, spinocellular carcinoma, basalioma), whose incidence is expected to increase in future. As some photoreactions can be inhibited or enhanced also by radiation outside their action spectrum, it is possible for changes in solar spectral radiation flux density to influence photo-induced reactions that are driven at wavelengths outside the UV-B range. The authors have performed studies for developing methods of quantifying individual UV sensitivity. In vitro studies have shown that UV-A dependent photoreactions can be partly inhibited by UV-B. A number of drugs, as well as sulphites, which are used as preservatives amongst other things, have been shown to have phototoxic properties that may be relevant to photocarcinogenesis. Irradiation tests on cell cultures for different UV-B ranges have shown that irradiation at shorter wavelengths leads to a stronger release of proinflammatory cytokines that ar longer wavelengths with the same dose. Altogether it can be said that despite compelling theoretical evidence it is not easily possible to predict the actual consequences of an increase in particular of short-wave UV-B radiation at the earth's surface. The assumed effects must be examined individually by appropriate methods. (orig.) [de

  5. Proceedings of the workshop on vacuum arc ion sources

    International Nuclear Information System (INIS)

    Brown, I.

    1996-08-01

    Topics included in the papers presented at this conference are: vacuum arc ion source development at GSI (Gesellschaft fuer Schwerionenforschung, Germany), ITEP (Institute for Theoretical and Experimental Physics, Russia), Lawrence Berkeley Laboratory, and ANSTO (Australian Nuclear Science and Technology Organization); triggers for vacuum arc sources; plasma distribution of cathodic arc deposition system; high ion charge states in vacuum arc ion sources; and gas and metal ion sources. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database

  6. Composite plastic coatings and face rolled materials technology, energy- and environment-saving, based on irradiation of liquid monomers by broad and high-current electron beams in vacuum

    Science.gov (United States)

    Vaisburd, David

    1994-05-01

    The technology is based on the well-known process of hardening some organic liquid monomers and oligomers (resins and lacquers) under the action of ionizing radiation, i.e. electron, ion, ultra-violet, laser, and X-ray beams. The main mechanism of hardening is 3D polymerization of initial monomers induced by irradiation. First of all 1D polymer chains are created. And the next stage is cross-linking of them. Numerical attempts to apply such a process for plastic materials production met some earnest difficulties. Our decision to perform the whole processing in vacuum changed radically the main properties of radiation induced hardening technology. The inhibition of polymerization by reactive oxygen became unessential. The output window foil of accelerator became unnecessary. Application of super broad beams such as 1 sq.m became possible. The entire efficiency of grid electricity was increased to 60% and it was not the limit. One of the main advantages is that the processing carried out in vacuum may satisfy the highest ecological standards. The technology developed is contamination free and environment-saving.

  7. Assembly of a Vacuum Chamber: A Hands-On Approach to Introduce Mass Spectrometry

    Science.gov (United States)

    Bussie`re, Guillaume; Stoodley, Robin; Yajima, Kano; Bagai, Abhimanyu; Popowich, Aleksandra K.; Matthews, Nicholas E.

    2014-01-01

    Although vacuum technology is essential to many aspects of modern physical and analytical chemistry, vacuum experiments are rarely the focus of undergraduate laboratories. We describe an experiment that introduces students to vacuum science and mass spectrometry. The students first assemble a vacuum system, including a mass spectrometer. While…

  8. Gravitation and vacuum field

    International Nuclear Information System (INIS)

    Tevikyan, R.V.

    1986-01-01

    This paper presents equations that describe particles with spins s = 0, 1/2, 1 completely and which also describe 2s + 2 limiting fields as E → ∞. It is shown that the ordinary Hilbert-Einstein action for the gravitation field must be augmented by the action for the Bose vacuum field. This means that one must introduce in the gravitational equations a cosmological term proportional to the square of the strength of the Bose vacuum field. It is shown that the theory of gravitation describes three realities: matter, field, and vacuum field. A new form of matter--the vacuum field--is introduced into field theory

  9. Nitric oxide is involved in integration of UV-B absorbing compounds among parts of clonal plants under a heterogeneous UV-B environment.

    Science.gov (United States)

    Liu, Xiao; Li, Qian; Yue, Ming; Zhang, Xiaofei; Zhang, Ruichang; Zhang, Bing; Wang, Ming

    2014-11-26

    In nature, ultraviolet-B (UV-B) radiation is highly heterogeneous, both spatially and temporally. Plants exposed to UV-B radiation produce UV-B absorbing compounds that function as a protective filter. For clonal plants under heterogeneous UV-B radiation conditions, integration among ramets can allow irradiated ramets to benefit un-irradiated ramets by causing them to increase their UV-B absorbing compounds content. In this study, we evaluated integration between pairs of clonal ramets of Glechoma longituba under heterogeneous or homogeneous UV-B conditions. We determined the levels of UV-B absorbing compounds, nitric oxide (NO) and hydrogen peroxide (H 2 O 2 ) and measured the activity of phenylalanine ammonia-lyase (PAL) in connected ramet pairs under homogeneous or heterogeneous UV-B conditions. Under heterogeneous UV-B conditions, the UV-B absorbing compounds content increased in leaves of irradiated and un-irradiated ramets, but not in the connecting stolons. The NO content increased in irradiated and un-irradiated leaves and stolons, but the H 2 O 2 content did not. Application of NO synthesis inhibitors and an NO blocker to irradiated ramets blocked the increase in UV-B absorbing compounds and PAL activity in un-irradiated ramets. These results suggested that NO is involved in the integration process for UV-B absorbing compounds among ramets. Our findings suggested that a UV-B-induced increase in NO transmits a signal to un-irradiated ramets via the stolon, leading to an increase in PAL activity and UV-B absorbing compounds content. The internal translocation of signal enables members of clonal networks to function as a whole unit and to mount an efficient defensive response to localized UV-B radiation. © 2014 Scandinavian Plant Physiology Society.

  10. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2008-01-01

    on high-arctic vegetation. They supplement previous investigations from the Arctic focussing on other variables like growth etc., which have reported no or minor plant responses to UV-B, and clearly indicates that UV-B radiation is an important factor affecting plant life at high-arctic Zackenberg......Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high......-arctic regions, manipulation experiments with various set-ups have been performed. Activation of plant defence mechanisms by production of UV-B absorbing compounds was significant in ambient UV-B in comparison to a filter treatment reducing the UV-B radiation. Despite the UV-B screening response, ambient UV...

  11. Sinapate esters provide greater UV-B attenuation than flavonoids in Arabidopsis thaliana (Brassicaceae)

    International Nuclear Information System (INIS)

    Sheahan, J.J.

    1996-01-01

    Mutants affected in flavonoid (tt4) or sinapate ester (fah1) biosynthesis were used to assess the relative importance of these phenolic UV photoprotectants in Arabidopsis. Flavonoid and sinapate ester absorption was more specific for UV-B than major nonphenolic chromophores in crude extracts. A new method of evaluating phenolic UV-B attenuation was developed using fluorescence analysis. When excited by UV-B, sinapate ester containing leaves and cotyledons had enhanced sinapate ester fluorescence and reduced chlorophyll fluorescence relative to those without sinapate esters. Although fluorescence analysis gave no evidence of UV-B attenuation by flavonoids, enhanced chlorophyll and protein loss were observed upon UV-B exposure in flavonoid-deficient leaves, suggesting they have another mechanism of UV-B protection. The hydroxycinnamates have been largely ignored as UV-B attenuating pigments. and the results indicate that greater attention should be paid to their role in attenuating UV-B

  12. Baking results of KSTAR vacuum vessel

    International Nuclear Information System (INIS)

    Kim, S. T.; Kim, Y. J.; Kim, K. M.; Im, D. S.; Joung, N. Y.; Yang, H. L.; Kim, Y. S.; Kwon, M.

    2009-01-01

    The Korea Superconducting Tokamak Advanced Research (KSTAR) is an advanced superconducting tokamak designed to establish a scientific and technological basis for an attractive fusion reactor. The fusion energy in the tokamak device is released through fusion reactions of light atoms such as deuterium or helium in hot plasma state, of which temperature reaches several hundreds of millions Celsius. The high temperature plasma is created in the vacuum vessel that provides ultra high vacuum status. Accordingly, it is most important for the vacuum condition to keep clean not only inner space but also surface of the vacuum vessel to make high quality plasma. There are two methods planned to clean the wall surface of the KSTAR vacuum vessel. One is surface baking and the other is glow discharge cleaning (GDC). To bake the vacuum vessel, De-Ionized (DI) water is heated to 130 .deg. C and circulated in the passage between double walls of the vacuum vessel (VV) in order to bake the surface. The GDC operation uses hydrogen and inert gas discharges. In this paper, general configuration and brief introduction of the baking result will be reported

  13. Microfabricated triggered vacuum switch

    Science.gov (United States)

    Roesler, Alexander W [Tijeras, NM; Schare, Joshua M [Albuquerque, NM; Bunch, Kyle [Albuquerque, NM

    2010-05-11

    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  14. Analytical and numerical tools for vacuum systems

    CERN Document Server

    Kersevan, R

    2007-01-01

    Modern particle accelerators have reached a level of sophistication which require a thorough analysis of all their sub-systems. Among the latter, the vacuum system is often a major contributor to the operating performance of a particle accelerator. The vacuum engineer has nowadays a large choice of computational schemes and tools for the correct analysis, design, and engineering of the vacuum system. This paper is a review of the different type of algorithms and methodologies which have been developed and employed in the field since the birth of vacuum technology. The different level of detail between simple back-of-the-envelope calculations and more complex numerical analysis is discussed by means of comparisons. The domain of applicability of each method is discussed, together with its pros and cons.

  15. Design of the CLIC Quadrupole Vacuum Chambers

    CERN Document Server

    Garion, C

    2010-01-01

    The Compact Linear Collider, under study, requires vacuum chambers with a very small aperture, of the order of 8 mm in diameter, and with a length up to around 2 m for the main beam quadrupoles. To keep the very tight geometrical tolerances on the quadrupoles, no bake out is allowed. The main issue is to reach UHV conditions (typically 10-9 mbar static pressure) in a system where the vacuum performance is driven by water outgassing. For this application, a thinwalled stainless steel vacuum chamber with two ante chambers equipped with NEG strips, is proposed. The mechanical design, especially the stability analysis, is shown. The key technologies of the prototype fabrication are given. Vacuum tests are carried out on the prototypes. The test set-up as well as the pumping system conditions are presented.

  16. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2011-01-01

    Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination...

  17. Is UV-B radiation affecting charophycean algae in shallow freshwater systems?

    NARCIS (Netherlands)

    de Bakker, NVJ; van Bodegom, PM; van de Poll, WH; Boelen, P; Nat, E; Rozema, J; Aerts, R

    The objective of this study was to determine the effects of UV-B radiation on charophycean algae under natural conditions, since charophytes enhance water transparency in freshwater systems and levels of UV-B radiation have increased by ozone depletion. Potential and actual UV-B effects were studied

  18. Is UV-B radiation affecting charophycean algae in shallow freshwater systems?

    NARCIS (Netherlands)

    Bakker, N.; van Bodegom, P.M.; Poll, W.H.; Boelen, P.; Nat, E.; Rozema, J.; Aerts, R.

    2005-01-01

    The objective of this study was to determine the effects of UV-B radiation on charophycean algae under natural conditions, since charophytes enhance water transparency in freshwater systems and levels of UV-B radiation have increased by ozone depletion. Potential and actual UV-B effects were studied

  19. Outdoor studies on the effects of solar UV-B on bryophytes: overview and methodology.

    NARCIS (Netherlands)

    Boelen, P.; de Boer, M.K.; Bakker, N.; Rozema, J.

    2006-01-01

    In this review all recent field studies on the effects of UV-B radiation on bryophytes are discussed. In most of the studies fluorescent UV-B tubes are used to expose the vegetation to enhanced levels of UV-B radiation to simulate stratospheric ozone depletion. Other studies use screens to filter

  20. Photosynthesis and pigment production in Liquidambar styraciflua - developmental and UV-B radiation effects

    International Nuclear Information System (INIS)

    Dillenburg, L.R.; Sullivan, J.H.; Teramura, A.H.

    1993-01-01

    Leaf expansion is very sensitive to different environmental stresses. This study describes ontogenetic changes in leaf size and physiology of Liquidambar styraciflua seedlings grown under UV-B irradiance levels simulating 0% (control), 16% (low) and 25% (high) stratospheric ozone reductions. Leaf size, light- and CO 2 -saturated rates of O 2 evolution (A max ), and concentration of chlorophylls (chl), and UV-B absorbing pigments were measured over a 4-week period. Specific leaf weight, A max and chl concentration increased with leaf age, except for a peak in A max at early development. Chlorophyll b concentration increased at a slower rate than chl a. Recently unfurled leaves has the greatest concentration of UV-B absorbing pigments. The effect of UV-B radiation on leaf growth and physiology were small and not dose-dependent. Expansion of leaves exposed to low UV-B was slightly delayed compared to controls (1.663 vs. 1.90 cm 2 /day), but final leaf size was unaffected by UV-B radiation. Physiological effects were less pronounced during the rapid expansion period. High UV-B tended to promote, while low UV-B inhibited accumulation of chl, especially chl a. In contrast, concentration of UV-B absorbing compounds was promoted only by low UV-B. The small inhibitory effects of UV-B on leaf growth and physiology suggests a high tolerance of the species to damaging UV-B radiation

  1. Outdoor studies on the effects of solar UV-B on bryophytes : Overview and methodology

    NARCIS (Netherlands)

    Boelen, P.; de Boer, M.K.; de Bakker, N.; Rozema, Jelte

    In this review all recent field studies on the effects of UV-B radiation on bryophytes are discussed. In most of the studies fluorescent UV-B tubes are used to expose the vegetation to enhanced levels of UV-B radiation to simulate stratospheric ozone depletion. Other studies use screens to filter

  2. Ultra high vacuum systems for accelerators

    International Nuclear Information System (INIS)

    Loefgren, P.

    2001-01-01

    Full text: In order to perform controlled, stable, and reproducible experiments, several research areas today require very low pressures. Maybe the most important example is the research that is performed in storage rings and accelerators where the lifetime and stability of particle beams depends critically on the vacuum conditions. Although the vacuum requirements ultimately depend on the kind of experiments that is performed, the studies of more and more rare and exotic species in storage rings and accelerators today pushes the demands on the vacuum conditions towards lower and lower pressures. The final pressure obtained in the vacuum system can often be the key factor for the outcome of an experiment. Pioneering work in vacuum technology has therefore often been performed at storage rings and accelerator facilities around the world. In order to reach pressures in the low UHV regime and lower (below 10 -11 mbar), several aspects have to be considered which implies choosing the proper materials, pumps and vacuum gauges. In the absence of gases inleaking from the outside, the rate of gas entering a vacuum system is determined by the release of molecules adsorbed on the surfaces and the outgassing from the bulk of the vacuum chamber walls. This means that the choice of material and, equally important, the pre treatment of the material, must be such that these rates are minimised. Today the most widely used material for vacuum applications are stainless steel. Besides its many mechanical advantages, it is resistant to corrosion and oxidation. If treated correctly the major gas source in a stainless steel chamber is hydrogen outgassing from the chamber walls. The hydrogen outgassing can be decreased by vacuum firing at 950 deg. C under vacuum. In addition to choosing the right materials the choice of vacuum pumps is important for the final pressure. Since no vacuum pump is capable of taking care of all kinds of gases found in the rest gas at pressures below 10 -11

  3. Development of vacuum die-casting process

    OpenAIRE

    Masashi Uchida

    2009-01-01

    The vacuum die-casting process, started 25 years ago in Japan, has been widely applied. This technology contributes very much to improvement of castings quality. The main factor causing the defects of die castings is the trapped air in the mold cavity, while the key technology of vacuum die-casting process is to avoid the trapped air effectively by evacuating the cavity before casting. At the same time, due to the shot speed and the casting pressure reduced in half, the service life of the di...

  4. Evaporation under vacuum condition

    International Nuclear Information System (INIS)

    Mizuta, Satoshi; Shibata, Yuki; Yuki, Kazuhisa; Hashizume, Hidetoshi; Toda, Saburo; Takase, Kazuyuki; Akimoto, Hajime

    2000-01-01

    In nuclear fusion reactor design, an event of water coolant ingress into its vacuum vessel is now being considered as one of the most probable accidents. In this report, the evaporation under vacuum condition is evaluated by using the evaporation model we have developed. The results show that shock-wave by the evaporation occurs whose behavior strongly depends on the initial conditions of vacuum. And in the case of lower initial pressure and temperature, the surface temp finally becomes higher than other conditions. (author)

  5. Vacuum system design

    International Nuclear Information System (INIS)

    Mathewson, A.G.

    1994-01-01

    In this paper the basic terms used by the vacuum engineer are presented and some useful formulae are also given. The concept of bakeout is introduced and the physics behind it explained. We concentrate on the effects in electron and proton storage rings which are due to energetic particle bombardment of the vacuum system walls and the ensuing gas desorption which may detrimentally affect the running of the machine. In addition, the problems associated with proton storage rings where the vacuum chamber is at cryogenic temperature are described

  6. Anthocyanin content and UVB sensitivity in Brassica rapa

    Energy Technology Data Exchange (ETDEWEB)

    Klaper, R.; Frankel, S.; Berenbaum, M.R. [Illinois Univ., Urbana, IL (United States)

    1996-06-01

    Three genotypes of rapid-cycling Brassica rapa that differ in anthocyanin content were grown in the presence and absence of elevated levels of shortwave ultraviolet (UBV, 280-325 nm) radiation. After 41 days, UVB exposure reduced leaf length and plant height of all genotypes. Plants with low levels of anthocyanin experienced a reduction in flower number twice as great as in genotypes with normal or elevated levels of anthocyanins; however, the absence of differences in flower production by genotypes with normal and elevated levels of anthocyanins suggests that factors other than anthocyanin pigmentation contribute to UVB responses in this species. (UK).

  7. Vacuum mechatronics first international workshop

    Energy Technology Data Exchange (ETDEWEB)

    Belinski, S.E.; Shirazi, M.; Hackwood, S.; Beni, G. (eds.) (California Univ., Santa Barbara, CA (USA))

    1989-01-01

    This report contains papers on the following topics: proposed epitaxial thin film growth in the ultra-vacuum of space; particle monitoring and control in vacuum processing equipment; electrostatic dust collector for use in vacuum systems; materials evaluation of an electrically noisy vacuum slip ring assembly; an overview of lubrication and associated materials for vacuum service; the usage of lubricants in a vacuum environment; guidelines and practical applications for lubrication in vacuum; recent development in leak detector and calibrator designs; the durability of ballscrews for ultrahigh vacuum; vacuum-compatible robot for self-contained manufacturing systems; the design, fabrication, and assembly of an advanced vacuum robotics system for space payload calibration; design criteria for mechanisms used in space; and concepts and requirements for semiconductor multiprocess integration in vacuum. These papers are indexed separately elsewhere.

  8. Ocular exposure to UV-B in sunlight: the Melbourne visual impairment project model.

    OpenAIRE

    McCarty, C. A.; Lee, S. E.; Livingston, P. M.; Bissinella, M.; Taylor, H. R.

    1996-01-01

    Quantification of ocular exposure to ultraviolet-B radiation (UV-B) has become an important public health issue, with reports that the ozone layer is being depleted worldwide. Ocular exposure to UV-B is determined by ambient UV-B levels, the duration of outdoor exposure, the proportion of ambient UV-B that reaches the eye, and the use of ocular protection. We have developed a simplified model for quantifying lifetime ocular UV-B exposure that can be used in large epidemiological surveys. Expo...

  9. Helical type vacuum container

    International Nuclear Information System (INIS)

    Owada, Kimio.

    1989-01-01

    Helical type vacuum containers in the prior art lack in considerations for thermal expansion stresses to helical coils, and there is a possibility of coil ruptures. The object of the present invention is to avoid the rupture of helical coils wound around the outer surface of a vacuum container against heat expansion if any. That is, bellows or heat expansion absorbing means are disposed to a cross section of a helical type vacuum container. With such a constitution, thermal expansion of helical coils per se due to temperature elevation of the coils during electric supply can be absorbed by expansion of the bellows or absorption of the heat expansion absorbing means. Further, this can be attained by arranging shear pins in the direction perpendicular to the bellows axis so that the bellows are not distorted when the helical coils are wound around the helical type vacuum container. (I.S.)

  10. Cold Vacuum Drying Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Located near the K-Basins (see K-Basins link) in Hanford's 100 Area is a facility called the Cold Vacuum Drying Facility (CVDF).Between 2000 and 2004, workers at the...

  11. A Planck Vacuum Cosmology

    Directory of Open Access Journals (Sweden)

    Daywitt W. C.

    2009-04-01

    Full Text Available Both the big-bang and the quasi-steady-state cosmologies originate in some type of Planck state. This paper presents a new cosmological theory based on the Planck- vacuum negative-energy state, a state consisting of a degenerate collection of negative- energy Planck particles. A heuristic look at the Einstein field equation provides a con- vincing argument that such a vacuum state could provide a theoretical explanation for the visible universe.

  12. UV-B and Mediterranean forest species: Direct effects and ecological consequences

    International Nuclear Information System (INIS)

    Paoletti, E.

    2005-01-01

    Experimental results from plants receiving elevated doses of UV-B radiation generally show that Mediterranean forest species are well protected against increases in UV-B radiation. Natural adaptations to water stress and excess light (elevated concentrations of UV-B screening compounds, leaf hairs, thick cuticle and epidermis), and UV-B responses (thickening of the cuticle, increase in carotenoids) may avoid or counter-balance UV-B radiation damage. This response confirms that Mediterranean forest vegetation is adapted to face oxidative stress factors, such as elevated tropospheric ozone concentrations, drought and high radiation, including UV-B. Nevertheless, in the long term, species-specific and season-specific differential responses in growth, physiology, phenology and reproductive behaviour may alter the interactions between species and lead to slow but important changes in ecosystem structure and function. - Mediterranean plant adaptations against water stress and excess light may also afford protection against UV-B

  13. Ambient UV-B radiation reduces PSII performance and net photosynthesis in high Arctic Salix arctica

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, Helge

    2011-01-01

    Ambient ultraviolet-B (UV-B) radiation potentially impacts the photosynthetic performance of high Arctic plants. We conducted an UV-B exclusion experiment in a dwarf shrub heath in NE Greenland (74°N), with open control, filter control, UV-B filtering and UV-AB filtering, all in combination......, nitrogen and UV-B absorbing compounds. Compared to a 60% reduced UV-B irradiance, the ambient solar UV-B reduced net photosynthesis in Salix arctica leaves fixed in the 45° position which exposed leaves to maximum natural irradiance. Also a reduced Calvin Cycle capacity was found, i.e. the maximum rate...... across position in the vegetation. These findings add to the evidence that the ambient solar UV-B currently is a significant stress factor for plants in high Arctic Greenland....

  14. Biological responses to current UV-B radiation in Arctic regions

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2008-01-01

    (mycorrhiza) or in the biomass of microbes in the soil of the root zone. However, the composition of the soil microbial community was different in the soils under ambient and reduced UV radiation after three treatment years. These results provide new insight into the negative impact of current UV-B fluxes......Depletion of the ozone layer and the consequent increase in solar ultraviolet-B radiation (UV-B) may impact living conditions for arctic plants significantly. In order to evaluate how the prevailing UV-B fluxes affect the heath ecosystem at Zackenberg (74°30'N, 20°30'W) and other high......-arctic regions, manipulation experiments with various set-ups have been performed. Activation of plant defence mechanisms by production of UV-B absorbing compounds was significant in ambient UV-B in comparison to a filter treatment reducing the UV-B radiation. Despite the UV-B screening response, ambient UV...

  15. Contrasting Responses of Marine and Freshwater Photosynthetic Organisms to UVB Radiation: A Meta-Analysis

    KAUST Repository

    Jin, Peng

    2017-03-14

    Ultraviolet-B (UVB) radiation is a global stressor that has profound impacts on freshwater and marine ecosystems. However, an analysis of the patterns of sensitivity to UVB radiation across aquatic photosynthetic organisms has not yet been published. Here, we performed a meta-analysis on results reported in 214 studies compiled from the published literature to quantify and compare the magnitude of responses of aquatic photosynthetic organisms to changes in UVB radiation. The meta-analysis was conducted on observations of marine (n = 893) and freshwater macroalgae (n = 126) and of marine (n = 1,087) and freshwater (n = 2,889) microalgae (total n = 4,995). Most of these studies (85%) analyzed the performance of organisms exposed to natural solar radiation when UVB was partially or totally reduced compared with the organismal performance under the full solar radiation spectrum, whereas the remaining 15% of the studies examined the responses of organisms to elevated UVB radiation mostly using artificial lamps. We found that marine photosynthetic organisms tend to be more sensitive than freshwater photosynthetic organisms to UVB radiation; responses to either decreased or increased UVB radiation vary among taxa; the mortality rate is the most sensitive of the trait responses to elevated UVB radiation, followed by changes in cellular and molecular traits; the sensitivity of microalgae to UVB radiation is dependent on size, with small-celled microalgae more sensitive than large-celled microalgae to UVB radiation. Thick macroalgae morphotypes were the less sensitive to UVB, but this effect could not be separated from phylogenetic differences. The high sensitivity of marine species, particularly the smallest photosynthetic organisms, to increased UVB radiation suggests that the oligotrophic ocean, a habitat comprising 70% of the world\\'s oceans with high UVB penetration and dominated by picoautotrophs, is extremely vulnerable to changes in UVB radiation.

  16. Synthesis and photoluminescence study of narrow-band UVB ...

    Indian Academy of Sciences (India)

    320 nm) and UVA: those rays closest to the visible spectrum that pass through glass and are the least harmful to the skin (320–400 nm). Ultraviolet B (UVB) has become the phototherapy treat- ment of choice for psoriasis, vitiligo, atopic dermatitis.

  17. Cooling Down Thermomorphogenesis by UV-B Signaling.

    Science.gov (United States)

    Yin, Ruohe

    2017-06-01

    PHYTOCHROME-INTERACTING FACTOR 4 (PIF4) is a key transcriptional regulator promoting plant responses to elevated ambient temperatures. A recent study reported that the ultraviolet B radiation (UV-B) photoreceptor UVR8 signaling pathway inhibits PIF4 via multiple mechanisms to repress plant responses to high ambient temperatures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Antioxidant Responses Induced by UVB Radiation in Deschampsia antarctica Desv.

    Directory of Open Access Journals (Sweden)

    Hans Köhler

    2017-05-01

    Full Text Available Deschampsia antarctica Desv. is one of two vascular plants that live in the Maritime Antarctic Territory and is exposed to high levels of ultraviolet-B (UVB radiation. In this work, antioxidant physiology of D. antarctica was studied in response to UVB induced oxidative changes. Samples were collected from Antarctica and maintained in vitro culture during 2 years. Plants were sub-cultured in a hydroponic system and exposed to 21.4 kJ m-2 day-1, emulating summer Antarctic conditions. Results showed rapid and significant increases in reactive oxygen species (ROS at 3 h, which rapidly decreased. No dramatic changes were observed in photosynthetic efficiency, chlorophyll content, and level of thiobarbituric acid reactive species (MDA. The enzymatic (superoxide dismutase, SOD and total peroxidases, POD and non-enzymatic antioxidant activity (total phenolic increased significantly in response to UVB treatment. These findings suggest that tolerance of D. antarctica to UVB radiation could be attributed to its ability to activate both enzymatic and non-enzymatic antioxidant systems.

  19. Developmental reprogramming by UV-B radiation in plants.

    Science.gov (United States)

    Dotto, Marcela; Casati, Paula

    2017-11-01

    Plants are extremely plastic organisms with the ability to adapt and respond to the changing environmental conditions surrounding them. Sunlight is one of the main resources for plants, both as a primary energy source for photosynthesis and as a stimulus that regulates different aspects of their growth and development. UV-B comprises wavelengths that correspond to a high energy region of the solar spectrum capable of reaching the biosphere, influencing plant growth. It is currently believed that plants are able to acclimate when growing under the influence of this radiation and perceive it as a signal, without stress signs. Nonetheless, many UV-B induced changes are elicited after DNA damage occurs as a consequence of exposure. In this review we focus on the influence of UV-B on leaf, flower and root development and emphasize the limited understanding of the molecular mechanisms for most of this developmental processes affected by UV-B documented over the years of research in this area. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Transcriptome analysis for UVB-induced phototoxicity in mouse retina.

    Science.gov (United States)

    An, Mi-Jin; Kim, Chul-Hong; Nam, Gyu-You; Kim, Dae-Hyun; Rhee, Sangmyung; Cho, Sung-Jin; Kim, Jung-Woong

    2018-01-01

    Throughout life, the human eye is continuously exposed to sunlight and artificial lighting. Ambient light exposure can lead to visual impairment and transient or permanent blindness. To mimic benign light stress conditions, Mus musculus eyes were exposed to low-energy UVB radiation, ensuring no severe morphological changes in the retinal structure post-exposure. We performed RNA-seq analysis to reveal the early transcriptional changes and key molecular pathways involved before the activation of the canonical cell death pathway. RNA-seq analysis identified 537 genes that were differentially modulated, out of which 126 were clearly up regulated (>2-fold, P retina. Gene ontology analysis revealed that UVB exposure affected pathways for cellular stress and signaling (eg, Creb3, Ddrgk1, Grin1, Map7, Uqcc2, Uqcrb), regulation of chromatin and gene expression (eg, Chd5, Jarid2, Kat6a, Smarcc2, Sumo1, Zfp84), transcription factors (eg, Asxl2, Atf7, Per1, Phox2a, Rxra), RNA processing, and neuronal genes (eg, B4gal2, Drd1, Grm5, Rnf40, Rnps1, Usp39, Wbp4). The differentially expressed genes from the RNA-seq analysis were validated by quantitative PCR. Both analyses yielded similar gene expression patterns. The genes and pathways identified here improve the understanding of early transcriptional responses to UVB irradiation. They may also help in elucidating the genes responsible for the inherent susceptibility of humans to UVB-induced retinal diseases. © 2017 Wiley Periodicals, Inc.

  1. Vacuum fused deposition modelling system to improve tensile ...

    African Journals Online (AJOL)

    This paper presents a possible solution to this problem by incorporating vacuum technology in FDM system to improve tensile strength of 3D printed specimens. In this study, a desktop FDM machine was placed and operated inside a low pressure vacuum chamber. The results obtained show an improvement of 12.83 % of ...

  2. Ozone depletion, related UVB changes and increased skin cancer incidence

    Science.gov (United States)

    Kane, R. P.

    1998-03-01

    Stratospheric ozone at middle latitudes shows a seasonal variation of about +/-20%, a quasi-biennial oscillation of 1-10% range and a long-term variation in which the level was almost steady up to about 1979 and declined thereafter to the present day by about 10%. These variations are expected to be reflected in solar UVB observed at the ground, but in an opposite direction. Thus UVB should have had a long-term increase of about 10-20%, which should cause an increase in skin cancer incidence of about 20-40%. Skin cancer incidence has increased all over the world, e.g. about 90% in USA during 1974-1990. It is popularly believed that this increase in skin cancer incidence is related to the recent ozone depletion. This seems to be incorrect, for two reasons. Firstly, the observed skin cancer increase is too large (90%) compared with the expected value (40%) from ozone depletion. Secondly, cancer does not develop immediately after exposure to solar UVB. The sunburns may occur within hours; but cancer development and detection may take years, even decades. Hence the observed skin cancer increase since 1974 (no data available for earlier periods) must have occurred due to exposure to solar UVB in the 1950s and 1960s, when there was no ozone depletion. Thus, the skin cancer increase must be attributed to harmful solar UVB levels existing even in the 1960s, accentuated later not by ozone depletion (which started only much later, by 1979) but by other causes, such as a longer human life span, better screening, increasing tendencies of sunbathing at beaches, etc., in affluent societies. On the other hand, the recent ozone depletion and the associated UVB increases will certainly take their toll; only that the effects will not be noticed now but years or decades from now. The concern for the future expressed in the Montreal Protocol for reducing ozone depletion by controlling CFC production is certainly justified, especially because increased UVB is harmful to animal and

  3. Buried chip skin grafting in neuropathic diabetic foot ulcers following vacuum-assisted wound bed preparation: enhancing a classic surgical tool with novel technologies.

    Science.gov (United States)

    Kopp, Jürgen; Kneser, Ulrich; Bach, Alexander D; Horch, Raymund E

    2004-09-01

    In patients with diabetes mellitus, complications such as polyneuropathy and peripheral angiopathy inevitably lead to diabetic foot complications including foot ulcers, gangrene, and osteoarthropathy. These conditions necessitate minor or major amputation as part of treatment. In patients with Charcot's arthropathy and predominant neuropathy, recurrent foot ulcers are common in areas of high pressure. Such high pressure is caused by the degrading of the architecture of the foot and inadequate footwear. These patients are a clinical challenge. A select group of such patients may benefit from free surgical tissue transfer, though free or local flap surgery is often difficult or even impossible owing to an impaired arterial circulation. In such wounds, surgical debridement followed by skin grafts often fail due to bacterial burden in the wounds. To circumvent these problems, the authors developed a therapeutic approach using buried chip skin grafting to close granulation wound beds in diabetic feet. Locally applied vacuum therapy (VAC) for wound bed preparation of chronic, nonresponsive foot ulcers and subsequent grafting using the burying technique with a minute fraction of skin was used. Firm closure was achieved. The closed wound was resistant to mechanical irritation.

  4. Properties of low-temperature deposited ZnO thin films prepared by cathodic vacuum arc technology on different flexible substrates

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Cheng-Tang [Department of Mechanical and Electron-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung City 804, Taiwan (China); Yang, Ru-Yuan, E-mail: ryyang@mail.npust.edu.tw [Graduate Institute of Materials Engineering, National Pingtung University of Science and Technology, Pingtung County 912, Taiwan (China); Weng, Min-Hang [Medical Devices and Opto-Electronics Equipment Department, Metal Industries Research and Development Center, Kaohsiung City 821, Taiwan (China); Huang, Chien-Wei [Department of Mechanical and Electron-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung City 804, Taiwan (China)

    2013-07-31

    Un-doped zinc oxide (ZnO) films were deposited on three different substrates (polyethylene terephthalate (PET), polyvinyl butyral (PVB) and polyimide (PI)) at a low temperature (< 75 °C) by cathode vacuum arc deposition. The microstructure, optical and electrical properties of the deposited films were investigated and discussed. All the deposited films reveal a preferred orientation with the c-axis perpendicular to the substrate, and an average transmittance of over 85% in the visible region. The calculated optical band gaps are around 2.6, 3.14 and 3.18 eV, respectively, for the ZnO films deposited on the PI, PVB and PET substrates. The lowest resistivity and the highest Hall mobility are 5.31 × 10{sup −3} Ω-cm and 15.16 cm{sup 2}/V-s for the ZnO film deposited on the PET substrate. - Highlights: • Polyethylene terephthalate, polyvinyl butyral and polyimide were used as substrates. • ZnO films were prepared by cathodic arc plasma deposition. • ZnO films have different properties due to different substrates. • The microstructure control of ZnO film on polymer substrate is important.

  5. Efficient Phosphorescent OLEDS Based on Vacuum Deposition ...

    African Journals Online (AJOL)

    Thereby, we demonstrate high-efficiency organic light-emitting diodes by incorporating a double emission layer {i.e. both doped with the green phosphorescent dye tris(phenylpyridine)iridium [Ir(ppy)3]} into p-i-n-type device structure based on vacuum deposition technology. The intrinsic and doped transports layers are ...

  6. Central Corneal Thickness Considered an Index of Corneal Hydration of the UVB Irradiated Rabbit Cornea as Influenced by UVB Absorber

    Czech Academy of Sciences Publication Activity Database

    Čejka, Čestmír; Luyckx, J.; Čejková, Jitka

    2012-01-01

    Roč. 61, č. 3 (2012), s. 299-306 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z50390512 Keywords : UVB irradiation * corneal thickness * pachymetry Subject RIV: FF - HEENT, Dentistry Impact factor: 1.531, year: 2012

  7. Role of vacuum in food preservation

    International Nuclear Information System (INIS)

    Bongirwar, D.R.

    1997-01-01

    Considerable progress has been made in the processing of foods using operations viz. drying, evaporation, distillation, concentration, centrifugation, filtration, irradiation, freeze drying, osmotic drying etc. to get ready to eat food, convenience food, pre cooked dried food. Vacuum technology in direct or indirect way has played a vital role in carrying out these food processing operations. The role of vacuum in getting these processes developed and its use in the development of these high quality products with respect to colour, flavour, texture and other attributes has been highlighted along with process details. (author)

  8. Seasonal responses of six Poaceae to differential levels of solar UV-B radiation

    International Nuclear Information System (INIS)

    Deckmyn, G.; Impens, I.

    1999-01-01

    The effects of changes in solar UV-B on the growth and pigmentation of six grass species from cold-temperate grasslands (Lolium perenne, Lolium multiflorum, Festuca arundinacea, Festuca rubra, Phleum pratense and Dactylis glomerata) in spring and summer were studied. The grasses were grown in greenhouses with different foils, resulting in three treatments: no UV-B, 80% of ambient and 90% of ambient UV-BBE (biologically effective UV-B). The results indicated important effects of ambient UV-B levels on grass, but the different species reacted in very different ways. Both morphology and biomass production were influenced by UV-B in some species. However, changes in biomass production did not necessarily occur within the same species as changes in morphology. The grasses were more sensitive in summer. Overall, only F. rubra was positively influenced by UV-B under all circumstances. The biomass of D. glomerata and L. perenne was reduced by UV-B in spring and summer. Morphological changes included reduced height and increased tillering. The sensitivity of the different species was partially explained by their ability to reduce their specific leaf area in response to UV-B. Only the more sensitive species showed increased production of protective pigments. Overall, there were important differences between the effect of a low level of UV-B, and the further increase in UV-B, indicating that several mechanisms are operating at different light levels. (author)

  9. Effect of UV-B radiation on biomass production, pigmentation and protein content of marine diatoms

    International Nuclear Information System (INIS)

    Doehler, G.

    1984-01-01

    Several species of marine diatoms were grown at + 18 0 C and + 22 0 C under normal air conditions (0.035 vol.% CO 2 ) at a light/dark alteration of 14.8 h. Intensity of white light was 1 mW (approx.= 5000 lux). An artifical nutrient solution of 35per mille salinity was used. Algae - harvested during exponential growth - were exposed to different intensities of UV-B radiation (439, 717 and 1230 J m -2 m -1 ) for 2 days. UV-B radiation depressed the growth of all tested marine diatoms. Low levels of UV-B resulted in a slight increase of the biomass production (dry weight) compared to not UV-B treated cells. Enhanced UV-B doses caused a diminution of the primary productivity in all species. Algae exposed to UV-B stress showed a marked decrease in the protein and pigment content (chlorophyll a, chlorophyll c 1 + c 2 and carotenoids). In + 22 0 C grown cells of Lauderia annulata and Thalassiosira rotula were more sensitive to UV-B radiation than those cultures grown at + 18 0 C. Bellerochea yucatanensis cells grown at + 22 0 C were less affected after UV-B exposure than at + 18 0 C grown algae. The UV-B sensibility and growth of the individual species varied in a mixture of several marine diatoms. Results were discussed with reference to the UV-B effect on metabolic processes. (orig.)

  10. UV-B Perception and Acclimation in Chlamydomonas reinhardtii[OPEN

    Science.gov (United States)

    Chappuis, Richard; Allorent, Guillaume

    2016-01-01

    Plants perceive UV-B, an intrinsic component of sunlight, via a signaling pathway that is mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8) and induces UV-B acclimation. To test whether similar UV-B perception mechanisms exist in the evolutionarily distant green alga Chlamydomonas reinhardtii, we identified Chlamydomonas orthologs of UVR8 and the key signaling factor CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1). Cr-UVR8 shares sequence and structural similarity to Arabidopsis thaliana UVR8, has conserved tryptophan residues for UV-B photoreception, monomerizes upon UV-B exposure, and interacts with Cr-COP1 in a UV-B-dependent manner. Moreover, Cr-UVR8 can interact with At-COP1 and complement the Arabidopsis uvr8 mutant, demonstrating that it is a functional UV-B photoreceptor. Chlamydomonas shows apparent UV-B acclimation in colony survival and photosynthetic efficiency assays. UV-B exposure, at low levels that induce acclimation, led to broad changes in the Chlamydomonas transcriptome, including in genes related to photosynthesis. Impaired UV-B-induced activation in the Cr-COP1 mutant hit1 indicates that UVR8-COP1 signaling induces transcriptome changes in response to UV-B. Also, hit1 mutants are impaired in UV-B acclimation. Chlamydomonas UV-B acclimation preserved the photosystem II core proteins D1 and D2 under UV-B stress, which mitigated UV-B-induced photoinhibition. These findings highlight the early evolution of UVR8 photoreceptor signaling in the green lineage to induce UV-B acclimation and protection. PMID:27020958

  11. Effects of UVB radiation on net community production in the upper global ocean

    KAUST Repository

    Garcia-Corral, Lara S.

    2016-08-31

    Aim Erosion of the stratospheric ozone layer together with oligotrophication of the subtropical ocean is leading to enhanced exposure to ultraviolet B (UVB) radiation in ocean surface waters. The impact of increased exposure to UVB on planktonic primary producers and heterotrophs is uncertain. Here we test the null hypothesis that net community production (NCP) of plankton communities in surface waters of the tropical and subtropical ocean is not affected by ambient UVB radiation and extend this test to the global ocean, including the polar oceans and the Mediterranean Sea using previous results. Location We conducted experiments with 131 surface communities sampled during a circumnavigation cruise along the tropical and subtropical ocean and combined these results with 89 previous reports encompassing the Atlantic, Pacific, Arctic and Southern Oceans and the Mediterranean Sea. Methods The use of quartz (transparent to UVB radiation) and borosilicate glass materials (opaque to most UVB) for incubations allowed us to compare NCP between communities where UVB is excluded and those receiving natural UVB radiation. Results We found that NCP varies when exposed to natural UVB radiation compared to those where UVB was removed. NCP of autotrophic communities tended to decrease under natural UVB radiation, whereas the NCP of heterotrophic communities tended to increase. However, these variations showed the opposite trend under higher levels of UVB radiation. Main conclusions Our results suggest that earlier estimates of NCP for surface communities, which were hitherto derived using materials blocking UVB radiation were biased, with the direction and magnitude of this bias depending on the metabolic status of the communities and the underwater penetration of UVB radiation.

  12. Baryogenesis in false vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Yuta [KEK Theory Center, IPNS, KEK, Tsukuba, Ibaraki (Japan); Yamada, Masatoshi [Kanazawa University, Institute for Theoretical Physics, Kanazawa (Japan)

    2017-09-15

    The null result in the LHC may indicate that the standard model is not drastically modified up to very high scales, such as the GUT/string scale. Having this in the mind, we suggest a novel leptogenesis scenario realized in the false vacuum of the Higgs field. If the Higgs field develops a large vacuum expectation value in the early universe, a lepton number violating process is enhanced, which we use for baryogenesis. To demonstrate the scenario, several models are discussed. For example, we show that the observed baryon asymmetry is successfully generated in the standard model with higher-dimensional operators. (orig.)

  13. Vacuum fusion of uranium

    International Nuclear Information System (INIS)

    Stohr, J.A.

    1957-01-01

    After having outlined that vacuum fusion and moulding of uranium and of its alloys have some technical and economic benefits (vacuum operations avoid uranium oxidation and result in some purification; precision moulding avoids machining, chip production and chemical reprocessing of these chips; direct production of the desired shape is possible by precision moulding), this report presents the uranium fusion unit (its low pressure enclosure and pumping device, the crucible-mould assembly, and the MF supply device). The author describes the different steps of cast production, and briefly comments the obtained results

  14. Killing the Copenhagen vacuum

    International Nuclear Information System (INIS)

    Flyvbjerg, H.

    1981-04-01

    One-loop corrections to the equation expressing the instability of the Nielsen-Olesen unstable mode are considered. These corrections radically change the equation, and introduce a critical field strength Bsub(c) upon which instability, and consequently the life or death of the Copenhagen Vacuum, depends. These results are obtained by consideration of renormalizability and dimensions alone. The evaluation of Bsub(c) requires a long and technical calculation to be published in a subsequent paper. A preliminary result indicates that the Copenhagen Vacuum survives. (Auth.)

  15. Evading death by vacuum

    OpenAIRE

    Barroso, A.; Ferreira, P. M.; Ivanov, I. P.; Santos, Rui; Silva, João P.

    2012-01-01

    In the Standard Model, the Higgs potential allows only one minimum at tree-level. But the open possibility that there might be two scalar doublets enriches the vacuum structure, allowing for the risk that we might now be in a metastable state, which we dub the panic vacuum. Current experiments at the LHC are probing the Higgs particle predicted as a result of the spontaneous symmetry breaking. Remarkably, in the two Higgs model with a softly broken U(1) symmetry, the LHC experiments already p...

  16. A rotating quantum vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Lorenci, V.A. de; Svaiter, N.F. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1996-11-01

    It was investigated which mapping has to be used to compare measurements made in a rotating frame to those made in an inertial frame. Using a non-Galilean coordinate transformation, the creation-annihilation operators of a massive scalar field in the rotating frame are not the same as those of an inertial observer. This leads to a new vacuum state(a rotating vacuum) which is a superposition of positive and negative frequency Minkowski particles. Polarization effects in circular accelerators in the proper frame of the electron making a connection with the inertial frame point of view were analysed. 65 refs.

  17. FMIT accelerator vacuum system

    International Nuclear Information System (INIS)

    Machalek, M.D.; Meyer, E.A.; Price, L.S.

    1979-01-01

    The Fusion Materials Irradiation Test (FMIT) Facility accelerator is being designed to continuously accelerate 100-mA deuterons to 25 MeV. High vacuum pumping of the accelerator structure and beam lines will be done by ion pumps and titanium sublimation pumps. The design of the roughing system includes a Roots blower/mechanical pump package. For economy the size of the system has been designed to operate at 10 -6 torr, where beam particle scattering on residual gases is negligible. For minimum maintenance in this neutron factory, the FMIT vacuum system is designed from the point of view of simplicity and reliability

  18. Vacuum Arc Ion Sources

    CERN Document Server

    Brown, I.

    2013-12-16

    The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the source has grown, so also have the operational characteristics been improved in a variety of different ways. Here we review the principles, design, and performance of vacuum arc ion sources.

  19. Analysis of Photosynthetic Characteristics and UV-B Absorbing Compounds in Mung Bean Using UV-B and Red LED Radiation

    Directory of Open Access Journals (Sweden)

    Fang-Min Li

    2014-01-01

    Full Text Available Mung bean has been reported to have antioxidant, antidiabetic, anti-inflammatory, and antitumor activities. Various factors have important effects on the types and contents of plant chemical components. In order to study quality of mung bean from different light sources, mung bean seedlings were exposed to red light-emitting diodes (LEDs and ultraviolet-B (UV-B. Changes in the growth parameters, photosynthetic characteristics, the concentrations of chlorophyll a and chlorophyll b and the content of UV-B absorbing compounds were measured. The results showed that photosynthetic characteristics and chlorophyll a and chlorophyll b concentrations were enhanced by red LEDs. The concentrations of UV-B absorbing compounds were enhanced by UV-B on the 20th day, while photosynthetic characteristics, plant length, and the concentrations of chlorophyll a and chlorophyll b were reduced by UV-B on the 40th day; at the same time the values of the stem diameter, plant fresh weight, dry weight, and the concentrations of UV-B absorbing compounds were enhanced. It is suggested that red LEDs promote the elongation of plant root growth and photosynthetic characteristics, while UV-B promotes horizontal growth of stems and the synthesis of UV-B absorbing compounds.

  20. CHEMICAL-THERMAL PROCESSING OF TRACTOR PARTS IN VACUUM AT APPLICATION OF TECHNOLOGY OF HARDENING IN THE MEDIUM OF INERT GASES

    Directory of Open Access Journals (Sweden)

    статья Редакционная

    2011-01-01

    Full Text Available Advantages of technology of hardening by inert gases are considered. It is shown that use of unit ModulTherm7/1 at RUP «MTZ» allows to improve quality of chemical thermal processing of details and to provide decrease of expenses for manufacture.

  1. Design of the ITER vacuum vessel

    International Nuclear Information System (INIS)

    Ioki, K.; Johnson, G.; Shimizu, K.; Williamson, D.

    1995-01-01

    The ITER vacuum vessel is a major safety barrier and must support electromagnetic loads during plasma disruptions and vertical displacement events (VDE) and withstand plausible accidents without losing confinement.The vacuum vessel has a double wall structure to provide structural and electrical continuity in the toroidal direction. The inner and outer shells and poloidal stiffening ribs between them are joined by welding, which gives the vessel the required mechanical strength. The space between the shells will be filled with steel balls and plate inserts to provide additional nuclear shielding. Water flowing in this space is required to remove nuclear heat deposition, which is 0.2-2.5% of the total fusion power. The minor and major radii of the tokamak are 3.9 m and 13 m respectively, and the overall height is 15 m. The total thickness of the vessel wall structure is 0.4-0.7 m.The inboard and outboard blanket segments are supported from the vacuum vessel. The support structure is required to withstand a large total vertical force of 200-300 MN due to VDE and to allow for differential thermal expansion.The first candidate for the vacuum vessel material is Inconel 625, due to its higher electric resistivity and higher yield strength, even at high temperatures. Type 316 stainless steel is also considered a vacuum vessel material candidate, owing to its large database and because it is supported by more conventional fabrication technology. (orig.)

  2. Recent advances in vacuum sciences and applications

    Science.gov (United States)

    Mozetič, M.; Ostrikov, K.; Ruzic, D. N.; Curreli, D.; Cvelbar, U.; Vesel, A.; Primc, G.; Leisch, M.; Jousten, K.; Malyshev, O. B.; Hendricks, J. H.; Kövér, L.; Tagliaferro, A.; Conde, O.; Silvestre, A. J.; Giapintzakis, J.; Buljan, M.; Radić, N.; Dražić, G.; Bernstorff, S.; Biederman, H.; Kylián, O.; Hanuš, J.; Miloševič, S.; Galtayries, A.; Dietrich, P.; Unger, W.; Lehocky, M.; Sedlarik, V.; Stana-Kleinschek, K.; Drmota-Petrič, A.; Pireaux, J. J.; Rogers, J. W.; Anderle, M.

    2014-04-01

    Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid-liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented.

  3. LEP vacuum chamber, prototype

    CERN Multimedia

    CERN PhotoLab

    1983-01-01

    Final prototype for the LEP vacuum chamber, see 8305170 for more details. Here we see the strips of the NEG pump, providing "distributed pumping". The strips are made from a Zr-Ti-Fe alloy. By passing an electrical current, they were heated to 700 deg C.

  4. LEP Vacuum Chamber

    CERN Multimedia

    1983-01-01

    This is a cut-out of a LEP vacuum chamber for dipole magnets showing the beam channel and the pumping channel with the getter (NEG) strip and its insulating supports. A water pipe connected to the cooling channel can also be seen at the back.The lead radiation shield lining is also shown. See also 8305563X.

  5. Inexpensive high vacuum feedthroughs.

    Science.gov (United States)

    Gerber, S.; Post, D.

    1973-01-01

    Description of the use of rigid coaxial cable in the construction of high vacuum coaxial and coaxial push-pull rotary motion feedthroughs. This type of feedthroughs is shown to be extremely cheap and simple to make and modify. It can be used for moderately high voltages and provides a continuous, well shielded, low-noise feedthrough cable in any desired configuration.

  6. ISR vacuum system

    CERN Multimedia

    CERN PhotoLab

    1970-01-01

    A pressure of 5 x 10-11 Torr has been obtained repreatedly in this pilot section of the ISR vacuum system. The pilot section is 45 m long is pumped by 9 sputter-ion pumps pf 350 l/s pumping speed, and is baked out at 200 degrees C before each pump down.

  7. ISR vacuum system

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    Some of the most important components of the vacuum system are shown. At the left, the rectangular box is a sputter-ion pump inside its bake-out oven. The assembly in the centre includes a sector valve, three roughing valves, a turbomolecular pump, a rotary backing pump and auxiliary equipment. At the right, the small elbow houses a Bayard-

  8. Straw detector: 1 - Vacuum: 0

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    The NA62 straw tracker is using pioneering CERN technology to measure charged particles from very rare kaon decays. For the first time, a large straw tracker with a 4.4 m2 coverage will be placed directly into an experiment’s vacuum tank, allowing physicists to measure the direction and momentum of charged particles with extreme precision. NA62 measurements using this technique will help physicists take a clear look at the kaon decay rate, which might be influenced by particles and processes that are not included in the Standard Model.   Straw ends are glued to an aluminium frame, a crucial step in the assembly of a module. The ends are then visually inspected before a leak test is performed.  “Although straw detectors have been around since the 1980s, what makes the NA62 straw trackers different is that they can work under vacuum,” explains Hans Danielsson from the PH-DT group leading the NA62 straw project. Straw detectors are basically small drift cha...

  9. Effect of enhanced UV-B radiation and of other stress factors on marine phytoplankton

    International Nuclear Information System (INIS)

    Doehler, G.

    1987-01-01

    The impact of UV-B stress on the uptake of inorganic nitrogen compounds by several marine diatoms has been studied. Synedra has shown specially strong sensitivity to UV-B radiation, whereas the Lithodesmium species isolated in Japan has been less damaged in the experiments. Uptake of 15 N-ammonium is much more affected than the uptake of 15 N-nitrate. Experiments with Ditylum have shown that exposure to UV-B radiation at different times of the day produces effects. Different response to UV-B exposure with simultaneous exposure to monochromatic light has likewise been observed. The reversible UV-B induced damage observed after the first day of exposure becomes irreversible upon second exposure. The pattern of 14 C- and 15 N-labelled amino acids is significantly changed by UV-B stress. (orig./KG) With 50 refs., 15 tabs., 51 figs [de

  10. Effects of Increased UVB radiation on plant-insect interactions: Plantago lanceolata and Junonia coenia

    International Nuclear Information System (INIS)

    McCloud, E.S.; Berenbaum, M.R.

    1993-01-01

    Seeds of P. lanceolata were collected from a local population and 4 replicates of 42 maternal families were grown for 90 days in the greenhouse with at two levels of supplemental UVB radiation (6 and 12 kJ day -1 BE 300 ). Higher UVB radiation increased leaf hair density and decreased plant size during early growth; family identity affected these also. Leaves excised from a subset of the plants were fed to ultimate instar larvae of J. coenia and assayed for iridoids. Increased UVB radiation did not alter the iridoid content of the leaves or the growth of the larvae. In a separate experiment, P. lanceolata growing under the two levels of UVB irradiation were infested with neonate larvae and larval growth was monitored. Larval growth was not markedly altered by enhanced UVB. These findings suggest that increased UVB is unlikely to alter the suitability of P. lanceolata as a host for J. coenia

  11. Vacuum in thermo field dynamics

    International Nuclear Information System (INIS)

    Matsumoto, H.

    1987-01-01

    The framework for thermo field dynamics is presented in the axiomatic form. It consists of the conditions for the quantum algebra and the conditions for the vacuum. Choices of nonequilibrium vacuums correspond to nonequilibrium phenomena. (orig.)

  12. Tritium handling in vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Gill, J.T. [Monsanto Research Corp., Miamisburg, OH (United States). Mound Facility; Coffin, D.O. [Los Alamos National Lab., NM (United States)

    1986-10-01

    This report provides a course in Tritium handling in vacuum systems. Topics presented are: Properties of Tritium; Tritium compatibility of materials; Tritium-compatible vacuum equipment; and Tritium waste treatment.

  13. The Raman spectrum character of skin tumor induced by UVB

    Science.gov (United States)

    Wu, Shulian; Hu, Liangjun; Wang, Yunxia; Li, Yongzeng

    2016-03-01

    In our study, the skin canceration processes induced by UVB were analyzed from the perspective of tissue spectrum. A home-made Raman spectral system with a millimeter order excitation laser spot size combined with a multivariate statistical analysis for monitoring the skin changed irradiated by UVB was studied and the discrimination were evaluated. Raman scattering signals of the SCC and normal skin were acquired. Spectral differences in Raman spectra were revealed. Linear discriminant analysis (LDA) based on principal component analysis (PCA) were employed to generate diagnostic algorithms for the classification of skin SCC and normal. The results indicated that Raman spectroscopy combined with PCA-LDA demonstrated good potential for improving the diagnosis of skin cancers.

  14. The effect of UVB on flavonoid biosynthesis in wild type and mutant petunia and arabidopsis

    International Nuclear Information System (INIS)

    Ryan, K.G.; Swinny, E.E.; Markham, K.R.; Winefield, C.

    2000-01-01

    Full text: Flavonoids may protect plants against damage by UVB radiation. Flavonoid composition and mRNA expression were determined following growth of plants under natural light, and under natural light with low UVB and with enhanced UVB. In wild-type Arabidopsis and Petunia, UVB induced an increase in total levels of flavonols and this was due to an up-regulation of, several genes coding for key enzymes in the phenylpropanoid pathway. In addition, UVB induced a higher rate of production of the di-hydroxylated si flavonol, quercetin glycoside than of the mono-hydroxylated equivalent, of kaempferol glycoside. Thus the ratio of quercetin to kaempferol increased with UVB treatment in wild type plants, and this suggests that the flavonoid r 3'hydroxylase (F3'H) enzyme, which converts dihydrokaempferol to dihydroquercetin, may play a key role in plant protection from UVB. Mutant plants of both species lacking this F3'H gene were grown under similar UV conditions. Leaves of the mutant Arabidopsis plant (tt7) did not contain quercetin, even under the enhanced UVB treatment. Under the low UVB treatment the total amount of flavonol was similar to the wild-type (Ler), but with increasing UVB, total flavonol (i.e. kaempferol) levels were significantly higher than in similarly treated wild type plants. In the Petunia F3'H mutant, low levels of quercetin were found even in the low UVB treatment, which indicates this variety may be producing some quercetin via an alternative pathway. Under UVB radiation, total flavonoids increased to levels significantly higher than in similarly treated wild type plants, and most of this material was kaempferol. These observations suggest that quercetin is the preferred protective flavonol in wild type plants, due perhaps to enhanced antioxidant or free radical scavenging activity. In mutant plants lacking the F3'H enzyme, the response is to produce a larger amount of a less effective photoprotectant

  15. LHC : The World's Largest Vacuum Systems being commissioned at CERN

    CERN Document Server

    Jiménez, J M

    2008-01-01

    When it switches on in 2008, the 26.7 km Large Hadron Collider (LHC) at CERN, will have the world's largest vacuum system operating over a wide range of pressures and employing an impressive array of vacuum technologies. This system is composed by 54 km of UHV vacuum for the circulating beams and 50 km of insulation vacuum around the cryogenic magnets and the liquid helium transfer lines. Over the 54 km of UHV beam vacuum, 48 km of this are at cryogenic temperature (1.9 K). The remaining 6 km of beam vacuum containing the insertions for "cleaning" the proton beams, radiofrequency cavities for accelerating the protons as well as beam-monitoring equipment is at ambient temperature and uses non-evaporable getter (NEG) coatings - a vacuum technology that was born and industrialized at CERN. The pumping scheme is completed using 780 ion pumps to remove noble gases and to provide pressure interlocks to the 303 vacuum safety valves. Pressure readings are provided by 170 Bayard-Alpert gauges and 1084 gauges (Pirani a...

  16. Caffeine eye drops protect against UV-B cataract.

    Science.gov (United States)

    Kronschläger, Martin; Löfgren, Stefan; Yu, Zhaohua; Talebizadeh, Nooshin; Varma, Shambhu D; Söderberg, Per

    2013-08-01

    The purpose of this study was to investigate if topically applied caffeine protects against in vivo ultraviolet radiation cataract and if so, to estimate the protection factor. Three experiments were carried out. First, two groups of Sprague-Dawley rats were pre-treated with a single application of either placebo or caffeine eye drops in both eyes. All animals were then unilaterally exposed in vivo to 8 kJ/m(2) UV-B radiation for 15 min. One week later, the lens GSH levels were measured and the degree of cataract was quantified by measurement of in vitro lens light scattering. In the second experiment, placebo and caffeine pre-treated rats were divided in five UV-B radiation dose groups, receiving 0.0, 2.6, 3.7, 4.5 or 5.2 kJ/m(2) UV-B radiation in one eye. Lens light scattering was determined after one week. In the third experiment, placebo and caffeine pre-treated rats were UV-B-exposed and the presence of activated caspase-3 was visualized by immunohistochemistry. There was significantly less UV-B radiation cataract in the caffeine group than in the placebo group (95% confidence interval for mean difference in lens light scattering between the groups = 0.10 ± 0.05 tEDC), and the protection factor for caffeine was 1.23. There was no difference in GSH levels between the placebo- and the caffeine group. There was more caspase-3 staining in UV-B-exposed lenses from the placebo group than in UV-B-exposed lenses from the caffeine group. Topically applied caffeine protects against ultraviolet radiation cataract, reducing lens sensitivity 1.23 times. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. A radiation hard vacuum switch

    Science.gov (United States)

    Boettcher, G.E.

    1988-07-19

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction. 3 figs.

  18. Optimal conditions of vacuum distillation process for obtaining the high grade pure magnesium

    Directory of Open Access Journals (Sweden)

    Matković Vladislav Lj.

    2014-01-01

    Full Text Available In this paper the procedure of obtaining of high purity magnesium by using the vacuum distillation process has been shown. Vacuum distillation process has been conducted under low and high vacuum at different operating temperatures and times. Also, the condenser structure in vacuum equipment is set up in such a way to get the optimal conditions for obtaining of high purity magnesium. Based on experimental results, optimal process parameters were determined which justify the economy and technology of the process.

  19. 5 February 2010: Romanian Former Minister of Justice V. Stoica (4th from left) visiting SM18 with, from left to right, University of Bucharest Faculty of Physics A. Costescu, DESY Hamburg C. Diaconu; Mrs Valeriu Stoica; Université de Montpellier II S. Ciulli; Technology Department Vacuum, Surfaces and Coatings group S. Ilie; Technology Department Head F. Bordry and Adviser for Russian Federation, Central and Eastern Europe T. Kurtyka.

    CERN Multimedia

    Maximilien Brice

    2010-01-01

    5 February 2010: Romanian Former Minister of Justice V. Stoica (4th from left) visiting SM18 with, from left to right, University of Bucharest Faculty of Physics A. Costescu, DESY Hamburg C. Diaconu; Mrs Valeriu Stoica; Université de Montpellier II S. Ciulli; Technology Department Vacuum, Surfaces and Coatings group S. Ilie; Technology Department Head F. Bordry and Adviser for Russian Federation, Central and Eastern Europe T. Kurtyka.

  20. Reproductive, morphological, and phytochemical responses of Arabidopsis thaliana ecotypes to enhanced UV-B radiation

    Energy Technology Data Exchange (ETDEWEB)

    Trumbull, V.L.; McCloud, E.S.; Paige, K.N. (Univ. of Illinois, Urbana, IL (United States))

    1994-06-01

    Two ecotypes of Arabidopsis thaliana, collected from Libya and Norway, were grown in the greenhouse under. UV-B doses of 0 and 10.5 kJ m[sup [minus]2] UV-B[sub BE]. The high UV-B dose simulated midsummer ambient conditions over Libya and a 40% reduction in stratospheric ozone over Norway. The Libyan ectotype, which originated from latitudes where solar UV-B is high, showed no UV-B induced damage to plant growth. However the Norwegian ecotype, which originated from latitudes where solar UV-B is low, showed a significant reduction in plant height, inflorescence weight, and rosette weight in response to enhanced UV-B. Although fruit and seed number for both ecotypes were unaffected by enhanced UV-B radiation the germination success of the seeds harvested from the irradiated Norwegian plants were significantly reduced. The two ecotypes also differed with respect to their accumulation of kaempferol, a putative UV-B protective filter. The Libyan ecotype increased kaempferol concentration by 38% over the 0 kJ treatment whereas the Norwegian ecotype increased by only 15%. These data suggest that, for these ecotypes, variation in UV-B sensitivity may be explained by the differential induction of UV-absorbing leaf pigments.

  1. Physiological effects of short acute UVB treatments in Chenopodium quinoa Willd.

    Science.gov (United States)

    Huarancca Reyes, Thais; Scartazza, Andrea; Castagna, Antonella; Cosio, Eric G; Ranieri, Annamaria; Guglielminetti, Lorenzo

    2018-01-10

    Increased ultraviolet B (UVB) radiation due to global change can affect plant growth and metabolism. Here, we evaluated the capacity of quinoa to resist under short acute UVB irradiation. Quinoa was daily exposed for 30 or 60 min to 1.69 W m -2 UVB. The results showed that 30 min exposure in 9 d-course did not cause severe alterations on photosynthetic pigments and flavonoids, but a significant increase of antioxidant capacity was observed. Otherwise, 60 min UVB in 5 d-course reduced almost all these parameters except for an increase in the de-epoxidation of xanthophyll cycle pigments and led to the death of the plants. Further studies of gas exchange and fluorescence measurements showed that 30 min UVB dramatically decrease stomatal conductance, probably associated to reactive oxygen species (ROS) production. Inhibition of photosynthetic electron transport was also observed, which could be a response to reduce ROS. Otherwise, irreversible damage to the photosynthetic apparatus was found with 60 min UVB probably due to severe ROS overproduction that decompensates the redox balance inducing UVB non-specific signaling. Moreover, 60 min UVB compromised Rubisco carboxylase activity and photosynthetic electron transport. Overall, these data suggest that quinoa modulates different response mechanisms depending on the UVB irradiation dosage.

  2. The symmetries of the vacuum

    International Nuclear Information System (INIS)

    Fleming, H.

    1985-01-01

    The vacuum equation of state required by cosmological inflation is taken seriously as a general property of the cosmological vacuum. This correctly restricts the class of theories which admit inflation. A model of such a vacuum is presented that leads naturally to the cosmological principle. (Author) [pt

  3. An Ethanol Extract Derived from Bonnemaisonia hamifera Scavenges Ultraviolet B (UVB) Radiation-Induced Reactive Oxygen Species and Attenuates UVB-Induced Cell Damage in Human Keratinocytes

    Science.gov (United States)

    Piao, Mei Jing; Hyun, Yu Jae; Cho, Suk Ju; Kang, Hee Kyoung; Yoo, Eun Sook; Koh, Young Sang; Lee, Nam Ho; Ko, Mi Hee; Hyun, Jin Won

    2012-01-01

    The present study investigated the photoprotective properties of an ethanol extract derived from the red alga Bonnemaisonia hamifera against ultraviolet B (UVB)-induced cell damage in human HaCaT keratinocytes. The Bonnemaisonia hamifera ethanol extract (BHE) scavenged the superoxide anion generated by the xanthine/xanthine oxidase system and the hydroxyl radical generated by the Fenton reaction (FeSO4 + H2O2), both of which were detected by using electron spin resonance spectrometry. In addition, BHE exhibited scavenging activity against the 1,1-diphenyl-2-picrylhydrazyl radical and intracellular reactive oxygen species (ROS) that were induced by either hydrogen peroxide or UVB radiation. BHE reduced UVB-induced apoptosis, as shown by decreased apoptotic body formation and DNA fragmentation. BHE also attenuated DNA damage and the elevated levels of 8-isoprostane and protein carbonyls resulting from UVB-mediated oxidative stress. Furthermore, BHE absorbed electromagnetic radiation in the UVB range (280–320 nm). These results suggest that BHE protects human HaCaT keratinocytes against UVB-induced oxidative damage by scavenging ROS and absorbing UVB photons, thereby reducing injury to cellular components. PMID:23242204

  4. Compact vacuum insulation embodiments

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-04-28

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

  5. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1993-01-05

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  6. Temperature control in vacuum

    International Nuclear Information System (INIS)

    Dearnaley, G.

    1986-01-01

    The patent concerns a method for controlling the temperature of silicon wafers (or samples), during ion beam treatment of the wafers, in a vacuum. The apparatus and method are described for irradiation and temperature control of the samples. The wafers are mounted on a drum which is rotated through the ion beam, and are additionally heated by infra-red lamps to achieve the desired temperature. (U.K.)

  7. Vacuum inhomogeneous cosmological models

    International Nuclear Information System (INIS)

    Hanquin, J.-L.

    1984-01-01

    The author presents some results concerning the vacuum cosmological models which admit a 2-dimensional Abelian group of isometries: classifications of these space-times based on the topological nature of their space-like hypersurfaces and on their time evolution, analysis of the asymptotical behaviours at spatial infinity for hyperbolical models as well as in the neighbourhood of the singularity for the models possessing a time singularity during their evolution. (Auth.)

  8. The effect of chronic exposure to artificial UVB radiation on the survival and reproduction of Daphnia magna across two generations.

    Science.gov (United States)

    Huebner, Judith D; Loadman, Nancy L; Wiegand, Murray D; Young, Donna L W; Warszycki, Laura-Anne

    2009-01-01

    We examined the effects of daily (chronic) exposure to artificial UVB radiation on the survival and reproduction of Daphnia magna over two generations. Control and experimental animals in each generation (parental and F1) were exposed to 16 h of UVA radiation and photosynthetically active radiation daily. In addition, experimental animals were exposed to 6 h of UVB during the middle of the light period. Survival and reproduction were followed for 12 days for each individual. Survival and production of F1 were significantly lower in the UVB exposed parental generation Daphnia than in controls. F1 exposure to UVB significantly decreased F1 survival and reproduction. Reproduction was lowest in UVB exposed F1 animals whose parents were also exposed to UVB. Adverse effects of UVB on offspring production may be magnified in successive generations suggesting that short-term experiments could underestimate the impact of increased UVB exposure on populations.

  9. Linalool prevents oxidative stress activated protein kinases in single UVB-exposed human skin cells.

    Science.gov (United States)

    Gunaseelan, Srithar; Balupillai, Agilan; Govindasamy, Kanimozhi; Ramasamy, Karthikeyan; Muthusamy, Ganesan; Shanmugam, Mohana; Thangaiyan, Radhiga; Robert, Beaulah Mary; Prasad Nagarajan, Rajendra; Ponniresan, Veeramani Kandan; Rathinaraj, Pierson

    2017-01-01

    Ultraviolet-B radiation (285-320 nm) elicits a number of cellular signaling elements. We investigated the preventive effect of linalool, a natural monoterpene, against UVB-induced oxidative imbalance, activation of mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling in HDFa cells. We observed that linalool treatment (30 μM) prevented acute UVB-irradiation (20 mJ/cm2) mediated loss of activities of antioxidant enzymes in HDFa cells. The comet assay results illustrate that linalool significantly prevents UVB-mediated 8-deoxy guanosine formation (oxidative DNA damage) rather than UVB-induced cyclobutane pyrimidine (CPD) formation. This might be due to its ability to prevent UVB-induced ROS formation and to restore the oxidative imbalance of cells. This has been reflected in UVB-induced overexpression of MAPK and NF-κB signaling. We observed that linalool inhibited UVB-induced phosphorylation of ERK1, JNK and p38 proteins of MAPK family. Linalool inhibited UVB-induced activation of NF-κB/p65 by activating IκBa. We further observed that UVB-induced expression of TNF-α, IL6, IL-10, MMP-2 and MMP-9 was modulated by linalool treatment in HDFa cells. Thus, linalool protects the human skin cells from the oxidative damages of UVB radiation and modulates MAPK and NF-κB signaling in HDFa cells. The present findings substantiate that linalool may act as a photoprotective agent against UVB-induced skin damages.

  10. The UVR8 UV-B Photoreceptor: Perception, Signaling and Response

    Science.gov (United States)

    Tilbrook, Kimberley; Arongaus, Adriana B.; Binkert, Melanie; Heijde, Marc; Yin, Ruohe; Ulm, Roman

    2013-01-01

    Ultraviolet-B radiation (UV-B) is an intrinsic part of sunlight that is accompanied by significant biological effects. Plants are able to perceive UV-B using the UV-B photoreceptor UVR8 which is linked to a specific molecular signaling pathway and leads to UV-B acclimation. Herein we review the biological process in plants from initial UV-B perception and signal transduction through to the known UV-B responses that promote survival in sunlight. The UVR8 UV-B photoreceptor exists as a homodimer that instantly monomerises upon UV-B absorption via specific intrinsic tryptophans which act as UV-B chromophores. The UVR8 monomer interacts with COP1, an E3 ubiquitin ligase, initiating a molecular signaling pathway that leads to gene expression changes. This signaling output leads to UVR8-dependent responses including UV-B-induced photomorphogenesis and the accumulation of UV-B-absorbing flavonols. Negative feedback regulation of the pathway is provided by the WD40-repeat proteins RUP1 and RUP2, which facilitate UVR8 redimerization, disrupting the UVR8-COP1 interaction. Despite rapid advancements in the field of recent years, further components of UVR8 UV-B signaling are constantly emerging, and the precise interplay of these and the established players UVR8, COP1, RUP1, RUP2 and HY5 needs to be defined. UVR8 UV-B signaling represents our further understanding of how plants are able to sense their light environment and adjust their growth accordingly. PMID:23864838

  11. Variability in tolerance to UV-B radiation among Beauveria spp. isolates.

    Science.gov (United States)

    Fernandes, Everton K K; Rangel, Drauzio E N; Moraes, Aurea M L; Bittencourt, Vânia R E P; Roberts, Donald W

    2007-11-01

    Solar radiation, particularly the UV-B component, negatively affects survival of entomopathogenic fungi in the field. In an effort to identify Beauveria spp. isolates with promise for use in biological control settings with high insolation, we examined 53 Beauveria bassiana isolates, 7 isolates of 4 other Beauveria spp. and Engyodontium albus (=Beauveria alba). The origins of these fungi varied widely as to host/substrate and country, but approximately 30% of these isolates were B. bassiana from ticks in Brazil. A preliminary trial with three B. bassiana isolates (Bb 19, CG 310 and CG 481) at several UV-B dosages indicated that 2h of weighted UV-B irradiance at 978mWm(-2) (providing a total dose of 7.04kJm(-2)) allowed separation of isolates into low, medium or high UV-B tolerance. This dose, therefore, was selected as a single dose to compare UV-B tolerances of all 60 Beauveria spp. isolates. There was high variability in tolerance to UV-B radiation among the B. bassiana isolates, ranging from virtually zero tolerance (e.g., Bb 03) to almost 80% tolerance (e.g., CG 228). In addition, surviving B. bassiana conidia demonstrated delayed germination; and this is likely to reduce virulence. Conidia of the other species were markedly more sensitive to UV-B, with E. albus (UFPE 3138) being the least UV-B tolerant. Among B. bassiana isolates originating from 0 degrees to 22 degrees latitudes, those from lower latitudes demonstrated statistically significant greater UV-B tolerances than those isolates from higher latitudes. Isolates from above 22 degrees , however, were unaffected by latitude of origin. A similar analysis based on host type did not indicate a correlation between original host and UV-B tolerance. The identification in this study of several B. bassiana isolates with relatively high UV-B tolerance will guide the selection of isolates for future arthropod microbial control experiments.

  12. Development of a Modified Vacuum Cleaner for Lunar Surface Systems

    Science.gov (United States)

    Toon, Katherine P.; Lee, Steve A.; Edgerly, Rachel D.

    2010-01-01

    The National Aeronautics and Space Administration (NASA) mission to expand space exploration will return humans to the Moon with the goal of maintaining a long-term presence. One challenge that NASA will face returning to the Moon is managing the lunar regolith found on the Moon's surface, which will collect on extravehicular activity (EVA) suits and other equipment. Based on the Apollo experience, the issues astronauts encountered with lunar regolith included eye/lung irritation, and various hardware failures (seals, screw threads, electrical connectors and fabric contamination), which were all related to inadequate lunar regolith mitigation. A vacuum cleaner capable of detaching, transferring, and efficiently capturing lunar regolith has been proposed as a method to mitigate the lunar regolith problem in the habitable environment on lunar surface. In order to develop this vacuum, a modified "off-the-shelf' vacuum cleaner will be used to determine detachment efficiency, vacuum requirements, and optimal cleaning techniques to ensure efficient dust removal in habitable lunar surfaces, EVA spacesuits, and air exchange volume. During the initial development of the Lunar Surface System vacuum cleaner, systematic testing was performed with varying flow rates on multiple surfaces (fabrics and metallics), atmospheric (14.7 psia) and reduced pressures (10.2 and 8.3 psia), different vacuum tool attachments, and several vacuum cleaning techniques in order to determine the performance requirements for the vacuum cleaner. The data recorded during testing was evaluated by calculating particulate removal, relative to the retained simulant on the tested surface. In addition, optical microscopy was used to determine particle size distribution retained on the surface. The scope of this paper is to explain the initial phase of vacuum cleaner development, including historical Apollo mission data, current state-of-the-art vacuum cleaner technology, and vacuum cleaner testing that has

  13. CERN's vacuums honoured to the full

    CERN Multimedia

    2002-01-01

    CERN's Cristoforo Benvenuti is awarded one of the most prestigious prizes in the world of vacuum techniques     Because we constantly run into such individuals, we tend to forget that CERN has specialists with world reputations. It takes the international prizes they win to remind us of the fact. One such prize, the American Vacuum Society (AVS)'s Gaede-Langmuir Award for 2002, has gone to Cristoforo Benvenuti, Leader of the Surfaces and Materials Technologies Group in EST Division. The award, conferred once every two years, is one of the leading prizes in the vacuum field. By coincidence, its very first winner was Pierre Auger, one of CERN's founding fathers, back in 1978. Cristoforo Benvenuti, a senior physicist who joined CERN in 1966, has been singled out for his work on getter technologies. These technologies made their name at CERN with the coming of LEP, where they were used for pumping the machine. Getter is a material with the property of capturing gas molecules and thereby actin...

  14. Changes in growth and 14CO2 fixation of Hordeum vulgare and Phaseolus vulgaris induced by UV-B radiation

    International Nuclear Information System (INIS)

    Moussa, H.R.; Khodary, S.A.

    2008-01-01

    Increased UV-B radiation on the earth's surface due to depletion of stratospheric ozone layer is one of the changes of current climate-change pattern. A field experiment was concluded to study the effects of solar ultraviolet-B (UV-B) radiation on growth parameters, photosynthetic efficiency (14CO2-fixation) and biochemical characteristics of barley (Hordeum vulgare) and common bean (Phaseolus vulgaris). Plants grown under ambient UV-B radiation were compared with those grown without UV-B by excluding ambient UV-B radiation. To exclude solar ambient UV-B radiation, the sunlight was filtered through a polyester film that selectively absorbed UV-B. For ambient UV-B effects, plants were grown under polyvinyl chloride (PVC) filters that transmitted the complete light spectrum. The results indicated increased shoot length, leaf area, dry matter accumulation, leaf area ratio and specific leaf weight in plants of both the crops grown without UV-B compared with those grown under ambient UV-B. Similarly, the rate of photosynthetic activity, chlorophyll content, nitrates reductase (NR) enzyme activity and sugar content. The effect of UV-B exclusion was clearer in common bean compared with that in barley. We conclude that monocot species may be less sensitive to increased solar UV-B due to ozone depletion than with dicots

  15. Growth under UV-B radiation increases tolerance to high-light stress in pea and bean plants

    NARCIS (Netherlands)

    Bolink, EM; van Schalkwijk, [No Value; Posthumus, F; van Hasselt, PR

    Pea (Pisum sativum L.) and bean (Phaseolus vulgaris L.) plants were exposed to enhanced levels of UV-B radiation in a growth chamber. Leaf discs of UV-B treated and control plants were exposed to high-light (HL) stress (PAR: 1200 mu mol m(-2) s(-1)) to study whether pre-treatment with UV-B affected

  16. Effects of ultraviolet-B (UV-B) radiation on two cryptogamic plants ...

    African Journals Online (AJOL)

    rudra

    In the present study we have investigated the effect of ultraviolet-B (UV-B) radiation on two cryptogamic plants (Xanthoria elegans and Bryum argenteum) growing at high altitude of central Himalayan region of India. These plants were naturally receiving UV-B radiation and were analyzed for photosynthetic pigments, UV-B ...

  17. The evolutionary response of plants to increased UV-B radiation: Field studies with Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Trumbull, V.L.; Paige, K.N.

    1995-01-01

    The response of a species to any environmental change is determined by both phenotypic and evolutionary adjustments. To date, the majority of research concerning the response of terrestrial plants to increased UV-B radiation has focused on phenotypic adjustments. Recently we have initiated field studies aimed at assessing genetic variation for UV-B sensitivity within a natural population of Arabidopsis thaliana. This population consists of at least eight discrete genotypes that have been confirmed by RAPD analysis. We used an incomplete block design to assess the impact of UV-B (ambient and ambient + 6 kJ) and PAR (low and high) on these genotypes. The high UV-B treatment caused a significant reduction in fruit number and plant height while the high PAR treatment caused a significant increase in these variables. In addition, there was a marginally significant (p=0.1) UV-B x PAR x maternal line interaction for fruit number, indicating that genetic variation for UV-B sensitivity within this population depends on the PAR environment. The combination of high UV-B and high PAR caused a change in fruit number (relative to the ambient UV-B/high PAR treatment) ranging from an increase of 24% to a decrease of 47%. This range was much smaller in the low PAR treatment. These results indicate the potential for increased UV-B radiation to act as an agent of natural selection within this population

  18. UV-B induces DNA damage and DNA synthesis delay in the marine diatom Cyclotella sp.

    NARCIS (Netherlands)

    Buma, A.G.J.; van Hannen, E.J; Veldhuis, M.J W; Gieskes, W.W C

    The effect of UV-B on the occurrence of DNA damage and consequences for the cell cycle were studied in the marine diatom Cyclotella sp. DNA damage was quantified by immunofluorescent detection of thymine dimers in nuclear DNA of single cells using flow cytometry. A total UV-B dose (biologically

  19. UV-B induces DNA damage and DNA synthesis delay in the marine diatom Cyclotella sp

    NARCIS (Netherlands)

    Buma, A.G.J.; Van Hannen, E.J.; Veldhuis, M.; Gieskes, W.W.C.

    1996-01-01

    The effect of UV-B on the occurrence of DNA damage and consequences for the cell cycle were studied in the marine diatom Cyclotella sp. DNA damage was quantified by immunofluorescent detection of thymine dimers in nuclear DNA of single cells using flow cytometry. A total UV-B dose (biologically

  20. Flavonoids are systemically induced by UV-B in Zea mays

    International Nuclear Information System (INIS)

    Tossi, V.E.; Lamattina, L.; Cassia, R.

    2009-01-01

    Flavonoid concentration is increased by UV-B irradiation, but it is unknown if this is a local or systemic response. Nitric oxide (NO) is a diffusible molecule involved in the UV-B response. NO regulates the expression of chalcone synthase (CHS), a key enzyme in the synthesis of flavonoids. The aim of this work was to determine if maize flavonoids are local or systemically induced by UV-B, and what is the participation of NO in this response. We have used maize seedlings where the second leaf was sprayed with H 2 O or cPTIO (a NO scavenger), and then completely covered (C), partially covered (P) or uncovered (U) before to be UV-B irradiated. The results show a 60% increase in the NO concentration of U, 42% in P and 35% in C respectively. Flavonoid concentration increased 90% in C, 70% in P and 40% in U. Flavonoid concentration was reduced when leaves were pretreated with cPTIO before the UV-B irradiation. RT-PCR shows that CHS was up-regulated by UV-B in U, P and C, but downregulated with cPTIO. We have analyzed the subcellular localization of flavonoid and NO in UV-B irradiated plants. Flavonoid localization was coincident with the NO presence in the irradiated surface of the leaves and flavonoids were detected in vesicles. These results indicate that flavonoids are systemically induced by UV-B in a NO-related mechanism. (authors)

  1. A Survey of the Potential Effects of Increasing UV-B Radiation on the Biosphere. Revision

    National Research Council Canada - National Science Library

    Martin, L

    1998-01-01

    ..., and an increase in UV-B radiation at the surface of the Earth. An increase in UV-B on average would increase the incidence rate of non-melanoma skin cancer worldwide, with an unproved but likely increase in melanoma skin cancer...

  2. Characterization of Actin Filament Dynamics during Mitosis in Wheat Protoplasts under UV-B Radiation.

    Science.gov (United States)

    Chen, Huize; Han, Rong

    2016-01-29

    Enhanced ultraviolet-B (UV-B) radiation is caused by the thinning ozone and affects photosynthesis and crop yield. Recently, UV-B radiation has been considered as an environmental signal that regulates plant growth. Elucidating the downstream effectors in UV-B-triggered pathways is of particular interest. Previous studies have shown that actin filaments (AFs) play many roles during cell physiological processes. However, the underlying response of AFs to UV-B radiation remains unclear. In this study, wheat protoplasts were isolated from 7-d-old leaves. The dynamics of AFs during mitosis were observed under different treatments. The protoplasts were treated with UV-B radiation, cytochalasin B (CB) and jasplakinolide (JAS). Ph-FITC labelling results revealed typical actin filament structures in the control group; AFs were rearranged under UV-B radiation. AFs polymerized into bundles during interphase, the preprophase band (PPB) structure was destroyed during prophase, and the AFs gathered into plaques during metaphase in response to UV-B radiation. During anaphase and telophase, the distribution of AFs was dispersed. Pharmacologic experiments revealed that CB induced apoptosis and JAS induced nuclear division without cytokinesis in wheat protoplasts. These results indicated that AFs respond to UV-B radiation during mitosis, supplying evidence of UV-B signal transduction in plants.

  3. Ocular exposure to UV-B in sunlight: the Melbourne visual impairment project model.

    Science.gov (United States)

    McCarty, C. A.; Lee, S. E.; Livingston, P. M.; Bissinella, M.; Taylor, H. R.

    1996-01-01

    Quantification of ocular exposure to ultraviolet-B radiation (UV-B) has become an important public health issue, with reports that the ozone layer is being depleted worldwide. Ocular exposure to UV-B is determined by ambient UV-B levels, the duration of outdoor exposure, the proportion of ambient UV-B that reaches the eye, and the use of ocular protection. We have developed a simplified model for quantifying lifetime ocular UV-B exposure that can be used in large epidemiological surveys. Exposure to UV-B is assessed and quantified using a model based on personal exposure over the six summer months. Data available for a population-based sample of 1150 people in the age range 40-98 years revealed a distribution in average annual lifetime ocular UV-B exposure similar to that reported in a previous study on which this model is based, and also demonstrate that people can recall lifetime personal behaviour related to ocular protection. It takes 12 minutes on average to collect these data. This model can be employed by researchers worldwide for uniform assessment of ocular UV-B exposure. PMID:8823956

  4. Recall of UVB-induced erythema in breast cancer patient receiving multiple drug chemotherapy

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Lindskov, R

    1984-01-01

    One day after sunbathing, a breast cancer patient received intravenous methotrexate, cyclophosphamide and 5-fluorouracil and had a recall of her UV erythema over the following week. Phototesting with UVA and UVB prior to and after a subsequent chemotherapy treatment showed a UVB-induced recall...

  5. Exposure of vitamins to UVB and UVA radiation generates singlet oxygen.

    Science.gov (United States)

    Knak, Alena; Regensburger, Johannes; Maisch, Tim; Bäumler, Wolfgang

    2014-05-01

    Deleterious effects of UV radiation in tissue are usually attributed to different mechanisms. Absorption of UVB radiation in cell constituents like DNA causes photochemical reactions. Absorption of UVA radiation in endogenous photosensitizers like vitamins generates singlet oxygen via photosensitized reactions. We investigated two further mechanisms that might be involved in UV mediated cell tissue damage. Firstly, UVB radiation and vitamins also generate singlet oxygen. Secondly, UVB radiation may change the chemical structure of vitamins that may change the role of such endogenous photosensitizers in UVA mediated mechanisms. Vitamins were irradiated in solution using monochromatic UVB (308 nm) or UVA (330, 355, or 370 nm) radiation. Singlet oxygen was directly detected and quantified by its luminescence at 1270 nm. All investigated molecules generated singlet oxygen with a quantum yield ranging from 0.007 (vitamin D3) to 0.64 (nicotinamide) independent of the excitation wavelength. Moreover, pre-irradiation of vitamins with UVB changed their absorption in the UVB and UVA spectral range. Subsequently, molecules such as vitamin E and vitamin K1, which normally exhibit no singlet oxygen generation in the UVA, now produce singlet oxygen when exposed to UVA at 355 nm. This interplay of different UV sources is inevitable when applying serial or parallel irradiation with UVA and UVB in experiments in vitro. These results should be of particular importance for parallel irradiation with UVA and UVB in vivo, e.g. when exposing the skin to solar radiation.

  6. Alleviation of UV-B stress in Arabidopsis using tea catechins | Lee ...

    African Journals Online (AJOL)

    Ultraviolet-B (UV-B) has been confirmed to be harmful to living organisms and it is of concern that the amount of UV-B radiation reaching the earth's surface is increasing because of the depletion of the stratospheric ozone layer. Effect of different levels of tea catechins on morphological damage and expression of chalcone ...

  7. The effects of UV-B radiation on European heathland species

    DEFF Research Database (Denmark)

    Björn, Lars O.; Callaghan, T. V.; Johnsen, Ib

    1997-01-01

    The effects of enhanced UV-B radiation on three examples of European shrub-dominated vegetation were studied in situ. The experiments were in High Arctic Greenland, northern Sweden and Greece, and at all sites investigated the interaction of enhanced UV-B radiation (simulating a 15% reduction...

  8. Effects of ultraviolet-B (UV-B) radiation on two cryptogamic plants ...

    African Journals Online (AJOL)

    Chlorofluorocarbons are mainly responsible for the depletion of stratospheric ozone layer which results in increase of UV-B radiation on earth's environment and causing adverse effects on flora. In the present study we have investigated the effect of ultraviolet-B (UV-B) radiation on two cryptogamic plants (Xanthoria elegans ...

  9. The effects of altered levels of UV-B radiation on an Antarctic grass and lichen

    NARCIS (Netherlands)

    Lud, D.; Huiskes, A.H.L.; Moerdijk-Poortvliet, T.C.W.; Rozema, J.J.

    2001-01-01

    We report a long-term experiment on the photosynthetic response of natural vegetation of Deschampsia antarctica (Poaceae) and Turgidosculum complicatulum (Lichenes) to altered UV-B levels on Leonie Island, Antarctica. UV-B above the vegetation was reduced by filter screens during two seasons. Half

  10. Protective effects of oleum curcumae wenchowensis on skin damage due to UVB

    International Nuclear Information System (INIS)

    Wang Zhicheng; Zhao Hongguang; Du Xiang; Li Yanbo; Guo Wei; Gong Shouliang; Xiao Jian; Yao Chongshun; Li Xiaokun

    2006-01-01

    Objective: To study the protective effects of oleum curcumae wenchowensis on skin damage exposed to UVB and its mechanism, and to provide the experimental basis for the protection of skin damage exposed to UVB. Methods: The skin of guinea pigs was exposed to UVB (28.38 J/cm 2 · 30 d) to establish the oxidative damage model. The skin erythema and the rough were observed during the experiment; the thickness of epiderm and the number of fibroblast were observed under light microscope after the experiment. The activities of GSH-Px, SOD, CAT and T-AOC and the contain of MDA in the supernate of skin homogenate were detected with biochemical methods. Results: The epiderm in UVB exposure group and blank group thickened, but that in protective group weren't observed; the number of fibroblast in UVB exposure group and blank group decreased, while that in protective group increased, but that in control group didn't. The content of MDA in the supemate of skin homogenate in UVB exposure group and blank group increased, but that in protective group deceased, and the activities of GSH-Px, SOD, CAT and T-AOC in UVB exposure group and blank group decreased, but those in protective group increased, and control group had no change. Conclusions: Oleum curcumae wenchowensis has the protective effects on skin damage exposed to UVB, which may be mediated by increasing the contain of antioxidases and eliminating the flee radical. (authors)

  11. Field research on the effects of UV-B filters on terrestrial Antarctic vegetation

    NARCIS (Netherlands)

    Huiskes, A.H.L.; Lud, D.; Moerdijk-Poortvliet, T.C.W.

    2001-01-01

    Patches of vegetation of six common species growing on Leonie Island (67 degrees 35' S, 68 degrees 20' W), Antarctic Peninsula region were covered with either UV-B transparent perspex screens or UV-B absorbing screens. Uncovered plots served as a control. Temperature and relative humidity were

  12. Increased permeability of reconstructed human epidermis from UVB-irradiated keratinocytes.

    Science.gov (United States)

    Löwenau, Lilian Julia; Zoschke, Christian; Brodwolf, Robert; Volz, Pierre; Hausmann, Christian; Wattanapitayakul, Suvara; Boreham, Alexander; Alexiev, Ulrike; Schäfer-Korting, Monika

    2017-07-01

    Extrinsic (photo) aging accelerates chronologically aging in the skin due to cumulative UV irradiation. Despite recent insights into the molecular mechanisms of fibroblast aging, age-related changes of the skin barrier function have been understudied. In contrast, the constantly increasing subpopulation of aged patients causes a clinical need for effective and safe (dermatological) treatment. Herein, we reconstructed human epidermis from UVB-irradiated keratinocytes (UVB-RHE). UVB-irradiated keratinocytes show higher activity of senescence associated β-galactosidase, less cell proliferation, and reduced viability. Higher amounts of β-galactosidase are also detectable in UVB-RHE. Moreover, UVB-RHE release more interleukin-1α and -8 into the culture medium and present altered differentiation with a thinner stratum corneum compared to normal RHE. For the first time, the permeation of testosterone and caffeine through UVB-irradiated RHE indicate a clear influence of the UVB stress on the skin barrier function. Impaired barrier function was confirmed by the increased permeation of testosterone and caffeine as well as by the increased penetration of dendritic core-multishell nanocarriers into the constructs. Taken together, UVB-RHE emulate hallmarks of skin aging and might contribute to an improved non-clinical development of medicinal or cosmetic products. Copyright © 2016. Published by Elsevier B.V.

  13. [Effects of enhanced UV-B radiation on the growth of five bryophytes in Changbai Mountains].

    Science.gov (United States)

    Wu, Yu-Huan; Gu, Yan-Hong; Liu, Peng; Zoltán, Tuba

    2007-09-01

    Five bryophytes (Rhytidium rugosum, Rhytidiadelphus triquetrus, Hylocomium splendens, Hylocomium pyrenaicum, and Polytrichum alpinum) were exposed to 0.2 kJ x m(-2) x d(-1) (visible light under native condition, CK), 3.0 kJ x m(-2) x d(-1) (simulated dose of UV-B irradiance at the tundra in Changbai Mountains, medium dose of UV-B irradiance, T1), and 6.0 kJ x m(-2) x d(-1) (high dose of UV-B irradiance, T2) to investigate the effects of enhanced UV-B radiation on plant height, biomass, and chlorophyll content. The results indicated that medium and high UV-B radiations decreased the plant height, biomass, and chlorophyll content of R. triquetrus and H. splendens by 32.3%, 62.4%, and 81.3%, and 21.4%, 59.4%, and 62.8%, respectively, and the relative growth rates were negative. Enhanced UV-B radiations had less effect on P. alpinum chlorophyll content but doubled its below-ground biomass, and slightly increased the biomass of R. rugosum. P. alpinum and R. rugosum had higher tolerance against UV-B radiation, while R. triquetrus and H. splendens were more sensitive to UV-B radiation.

  14. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum

    Energy Technology Data Exchange (ETDEWEB)

    Albert, K.R.; Ro-Poulsen, H. (Univ. of Copenhagen, Dept. of Terrestrial Ecology, Copenhagen (DK)); Mikkelsen, T.N. (Technical Univ. of Denmark, Risoe National Laboratory for Sustainable Energy, Biosystems Dept., Roskilde (DK))

    2008-06-15

    An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry). Leaf area, biomass, carbon, nitrogen and UV-B-absorbing compounds were determined from a late season harvest. Compared with the reduced UV-B treatment, the plants in ambient UV-B were found to have a higher content of UV-B-absorbing compounds, and canopy net photosynthesis was as an average 23% lower during the season. By means of the JIP-test, it was found that the potential of processing light energy through the photosynthetic machinery was slightly reduced in ambient UV-B. This indicates that not only the UV-B effects on PSII may be responsible for some of the observed reduction of photosynthesis but also the effects on other parts of the photosynthetic machinery, e.g. the Calvin cycle, might be important. The 60% reduction of the UV-B irradiance used in this study implies a higher relative change in the UV-B load than many of the supplemental experiments do, but the substantial effect on photosynthesis clearly indicates that V. uliginosum is negatively affected by the current level of UV-B. (au)

  15. Progress of ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Ioki, K., E-mail: Kimihiro.Ioki@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Bayon, A. [F4E, c/ Josep Pla, No. 2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Choi, C.H.; Daly, E.; Dani, S.; Davis, J.; Giraud, B.; Gribov, Y.; Hamlyn-Harris, C.; Jun, C.; Levesy, B. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Kim, B.C. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Kuzmin, E. [NTC “Sintez”, Efremov Inst., 189631 Metallostroy, St. Petersburg (Russian Federation); Le Barbier, R.; Martinez, J.-M. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Pathak, H. [ITER-India, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382025 (India); Preble, J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Sa, J.W. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Terasawa, A.; Utin, Yu. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); and others

    2013-10-15

    Highlights: ► This covers the overall status and progress of the ITER vacuum vessel activities. ► It includes design, R and D, manufacturing and approval process of the regulators. ► The baseline design was completed and now manufacturing designs are on-going. ► R and D includes ISI, dynamic test of keys and lip-seal welding/cutting technology. ► The VV suppliers produced full-scale mock-ups and started VV manufacturing. -- Abstract: Design modifications were implemented in the vacuum vessel (VV) baseline design in 2011–2012 for finalization. The modifications are mostly due to interface components, such as support rails and feedthroughs for the in-vessel coils (IVC). Manufacturing designs are being developed at the domestic agencies (DAs) based on the baseline design. The VV support design was also finalized and tests on scale mock-ups are under preparation. Design of the in-wall shielding (IWS) has progressed, considering the assembly methods and the required tolerances. Further modifications are required to be consistent with the DAs’ manufacturing designs. Dynamic tests on the inter-modular and stub keys to support the blanket modules are being performed to measure the dynamic amplification factor (DAF). An in-service inspection (ISI) plan has been developed and R and D was launched for ISI. Conceptual design of the VV instrumentation has been developed. The VV baseline design was approved by the agreed notified body (ANB) in accordance with the French Nuclear Pressure Equipment Order procedure.

  16. Progress of ITER vacuum vessel

    International Nuclear Information System (INIS)

    Ioki, K.; Bayon, A.; Choi, C.H.; Daly, E.; Dani, S.; Davis, J.; Giraud, B.; Gribov, Y.; Hamlyn-Harris, C.; Jun, C.; Levesy, B.; Kim, B.C.; Kuzmin, E.; Le Barbier, R.; Martinez, J.-M.; Pathak, H.; Preble, J.; Sa, J.W.; Terasawa, A.; Utin, Yu.

    2013-01-01

    Highlights: ► This covers the overall status and progress of the ITER vacuum vessel activities. ► It includes design, R and D, manufacturing and approval process of the regulators. ► The baseline design was completed and now manufacturing designs are on-going. ► R and D includes ISI, dynamic test of keys and lip-seal welding/cutting technology. ► The VV suppliers produced full-scale mock-ups and started VV manufacturing. -- Abstract: Design modifications were implemented in the vacuum vessel (VV) baseline design in 2011–2012 for finalization. The modifications are mostly due to interface components, such as support rails and feedthroughs for the in-vessel coils (IVC). Manufacturing designs are being developed at the domestic agencies (DAs) based on the baseline design. The VV support design was also finalized and tests on scale mock-ups are under preparation. Design of the in-wall shielding (IWS) has progressed, considering the assembly methods and the required tolerances. Further modifications are required to be consistent with the DAs’ manufacturing designs. Dynamic tests on the inter-modular and stub keys to support the blanket modules are being performed to measure the dynamic amplification factor (DAF). An in-service inspection (ISI) plan has been developed and R and D was launched for ISI. Conceptual design of the VV instrumentation has been developed. The VV baseline design was approved by the agreed notified body (ANB) in accordance with the French Nuclear Pressure Equipment Order procedure

  17. Vacuum-assisted drainage in cardiopulmonary bypass: advantages and disadvantages.

    Science.gov (United States)

    Carvalho Filho, Elio Barreto de; Marson, Fernando Augusto de Lima; Costa, Loredana Nilkenes Gomes da; Antunes, Nilson

    2014-01-01

    Systematic review of vacuum assisted drainage in cardiopulmonary bypass, demonstrating its advantages and disadvantages, by case reports and evidence about its effects on microcirculation. We conducted a systematic search on the period 1997-2012, in the databases PubMed, Medline, Lilacs and SciELO. Of the 70 selected articles, 26 were included in the review. Although the vacuum assisted drainage has significant potential for complications and requires appropriate technology and professionalism, prevailed in literature reviewed the concept that vacuum assisted drainage contributed in reducing the rate of transfusions, hemodilutions, better operative field, no significant increase in hemolysis, reduced complications surgical, use of lower prime and of smaller diameter cannulas.

  18. The vacuum platform

    Science.gov (United States)

    McNab, A.

    2017-10-01

    This paper describes GridPP’s Vacuum Platform for managing virtual machines (VMs), which has been used to run production workloads for WLCG and other HEP experiments. The platform provides a uniform interface between VMs and the sites they run at, whether the site is organised as an Infrastructure-as-a-Service cloud system such as OpenStack, or an Infrastructure-as-a-Client system such as Vac. The paper describes our experience in using this platform, in developing and operating VM lifecycle managers Vac and Vcycle, and in interacting with VMs provided by LHCb, ATLAS, ALICE, CMS, and the GridPP DIRAC service to run production workloads.

  19. R&D ERL: Vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Mapes, M.; Smart, L.; Weiss, D.; Steszyn, A.; Todd, R.

    2010-01-01

    The ERL Vacuum systems are depicted in a figure. ERL has eight vacuum volumes with various sets of requirements. A summary of vacuum related requirements is provided in a table. Five of the eight volumes comprise the electron beamline. They are the 5-cell Superconducting RF Cavity, Superconducting e-gun, injection, loop and beam dump. Two vacuum regions are the individual cryostats insulating the 5-cell Superconducting RF Cavity and the Superconducting e-gun structures. The last ERL vacuum volume not shown in the schematic is the laser transport line. The beamline vacuum regions are separated by electropneumatic gate valves. The beam dump is common with loop beamline but is considered a separate volume due to geometry and requirements. Vacuum in the 5-cell SRF cavity is maintained in the {approx}10{sup -9} torr range at room temperature by two 20 l/s ion pumps and in the e-gun SRF cavity by one 60 l/s ion pump. Vacuum in the SRF cavities operated at 2{sup o}K is reduced to low 10{sup -11} torr via cryopumping of the cavity walls. The cathode of the e-gun must be protected from poisoning, which can occur if vacuum adjacent to the e-gun in the injection line exceeds 10-11 torr range in the injection warm beamline near the e-gun exit. The vacuum requirements for beam operation in the loop and beam dump are 10-9 torr range. The beamlines are evacuated from atmospheric pressure to high vacuum level with a particulate free, oil free turbomolecular pumping cart. 25 l/s shielded ion pumps distributed throughout the beamlines maintain the vacuum requirement. Due to the more demanding vacuum requirement of the injection beamline proximate to the e-gun, a vacuum bakeout of the injection beamline is required. In addition, two 200 l/s diode ion pumps and supplemental pumping provided by titanium sublimation pumps are installed in the injection line just beyond the exit of the e-gun. Due to expected gas load a similar pumping arrangement is planned for the beam dump. The

  20. Impact of increasing Ultraviolet-B (UV-B) radiation on photosynthetic processes.

    Science.gov (United States)

    Kataria, Sunita; Jajoo, Anjana; Guruprasad, Kadur N

    2014-08-01

    Increased UV-B radiation on the earth's surface due to depletion of stratospheric ozone layer is one of the changes of current climate-change pattern. The deleterious effects of UV-B radiation on photosynthesis and photosynthetic productivity of plants are reviewed. Perusal of relevant literature reveals that UV-B radiation inflicts damage to the photosynthetic apparatus of green plants at multiple sites. The sites of damage include oxygen evolving complex, D1/D2 reaction center proteins and other components on the donor and acceptor sides of PS II. The radiation inactivates light harvesting complex II and alters gene expression for synthesis of PS II reaction center proteins. Mn cluster of water oxidation complex is the most important primary target of UV-B stress whereas D1 and D2 proteins, quinone molecules and cytochrome b are the subsequent targets of UV-B. In addition, photosynthetic carbon reduction is also sensitive to UV-B radiation which has a direct effect on the activity and content of Rubisco. Some indirect effects of UV-B radiation include changes in photosynthetic pigments, stomatal conductance and leaf and canopy morphology. The failure of protective mechanisms makes PS II further vulnerable to the UV-B radiation. Reactive oxygen species are involved in UV-B induced responses in plants, both as signaling and damaging agents. Exclusion of ambient UV components under field conditions results in the enhancement of the rate of photosynthesis, PS II efficiency and subsequently increases the biomass accumulation and crop yield. It is concluded that predicted future increase in UV-B irradiation will have significant impact on the photosynthetic efficiency and the productivity of higher plants. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Particle contamination in vacuum systems

    International Nuclear Information System (INIS)

    Martignac, J.; Bonin, B.; Henriot, C.; Poupeau, J.P.; Koltchakian, I.; Kocic, D.; Herbeaux, Ch.; Marx, J.P.

    1996-01-01

    Many vacuum devices, like RF cavities, are sensitive to particle contamination. This fact has motivated a considerable effort of cleanliness from the SRF community. The first results of a general study trying to identify the most contaminating steps during assembly and vacuum operation of the cavity is reported. The steps investigated here are gasket assembly, evacuation and venting of the vacuum system, and operation of sputter ion pumps. (author)

  2. Ultra High Vacuum Sputtering System

    Science.gov (United States)

    1991-07-25

    NO. NO. Washington, D.C. 20332-6448 E.. 1,1. T IT LE (Incirot Securi ty Ciassificalion) (U L t ra High Vacuum Spattering System _1__ 12. PERSONAL...ABSTRACT (Continue on reuerse it necessary and identify by bioc, number) This grant provided for the purchase of an ultra high vacuum sputtering system, for...FOR GRANT FROM DEFENSE UNIVERSITY RESEARCH INSTRUMENTATION PROGRAM Grant no. AFOSR-89-0138 Date Submitted: 27 July, 1991 Title: Ultra High Vacuum Sputtering

  3. Big Bang or vacuum fluctuation

    International Nuclear Information System (INIS)

    Zel'dovich, Ya.B.

    1980-01-01

    Some general properties of vacuum fluctuations in quantum field theory are described. The connection between the ''energy dominance'' of the energy density of vacuum fluctuations in curved space-time and the presence of singularity is discussed. It is pointed out that a de-Sitter space-time (with the energy density of the vacuum fluctuations in the Einstein equations) that matches the expanding Friedman solution may describe the history of the Universe before the Big Bang. (P.L.)

  4. Of vacuum and gas

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    A new LHCb programme is delving into uncharted waters for the LHC: exploring how protons interact with noble gases inside the machine pipe. While, at first glance, it may sound risky for the overall quality of the vacuum in the machine, the procedure is safe and potentially very rich in rewards. The results could uncover the high-energy helium-proton cross-section (with all the implications thereof), explore new boundaries of the quark-gluon plasma and much more.   As the beam passes through LHCb, interactions with neon gas allow the experiment to measure the full beam profile. In this diagram, beam 1 (blue) and beam 2 (red) are measured by the surrounding VELO detector. It all begins with luminosity. In 2011, LHCb set out to further improve its notoriously precise measurements of the beam profile, using the so-called Beam-Gas Imaging (BGI) method. BGI does exactly what it says on the tin: a small amount of gas is inserted into the vacuum, increasing the rate of collisions around the interaction ...

  5. Vacuum leak detector and method

    Science.gov (United States)

    Edwards, Jr., David

    1983-01-01

    Apparatus and method for detecting leakage in a vacuum system involves a moisture trap chamber connected to the vacuum system and to a pressure gauge. Moisture in the trap chamber is captured by freezing or by a moisture adsorbent to reduce the residual water vapor pressure therein to a negligible amount. The pressure gauge is then read to determine whether the vacuum system is leaky. By directing a stream of carbon dioxide or helium at potentially leaky parts of the vacuum system, the apparatus can be used with supplemental means to locate leaks.

  6. PDX vacuum vessel stress analysis

    International Nuclear Information System (INIS)

    Nikodem, Z.D.

    1975-01-01

    A stress analysis of PDX vacuum vessel is described and the summary of results is presented. The vacuum vessel is treated as a toroidal shell of revolution subjected to an internal vacuum. The critical buckling pressure is calculated. The effects of the geometrical discontinuity at the juncture of toroidal shell head and cylindrical outside wall, and the concavity of the cylindrical wall are examined. An effect of the poloidal field coil supports and the vessel outside supports on the stress distribution in the vacuum vessel is determined. A method evaluating the influence of circular ports in the vessel wall on the stress level in the vessel is outlined

  7. Vacuum metastability with black holes

    International Nuclear Information System (INIS)

    Burda, Philipp; Gregory, Ruth; Moss, Ian G. annd

    2015-01-01

    We consider the possibility that small black holes can act as nucleation seeds for the decay of a metastable vacuum, focussing particularly on the Higgs potential. Using a thin-wall bubble approximation for the nucleation process, which is possible when generic quantum gravity corrections are added to the Higgs potential, we show that primordial black holes can stimulate vacuum decay. We demonstrate that for suitable parameter ranges, the vacuum decay process dominates over the Hawking evaporation process. Finally, we comment on the application of these results to vacuum decay seeded by black holes produced in particle collisions.

  8. Historical evolution toward achieving ultrahigh vacuum in JEOL electron microscopes

    CERN Document Server

    Yoshimura, Nagamitsu

    2014-01-01

    This book describes the developmental history of the vacuum system of the transmission electron microscope (TEM) at the Japan Electron Optics Laboratory (JEOL) from its inception to its use in today’s high-technology microscopes. The author and his colleagues were engaged in developing vacuum technology for electron microscopes (JEM series) at JEOL for many years. This volume presents a summary and explanation of their work and the technology that makes possible a clean ultrahigh vacuum. The typical users of the TEM are top-level researchers working at the frontiers of new materials or with new biological specimens. They often use the TEM under extremely severe conditions, with problems sometimes occurring in the vacuum system of the microscopes. JEOL engineers then must work as quickly as possible to improve the vacuum evacuation system so as to prevent the recurrence of such problems. Among the wealth of explanatory material in this book are examples of users’ reports of problems in the vacuum system of...

  9. Design and construction of Alborz tokamak vacuum vessel system

    International Nuclear Information System (INIS)

    Mardani, M.; Amrollahi, R.; Koohestani, S.

    2012-01-01

    Highlights: ► The Alborz tokamak is a D-shape cross section tokamak that is under construction in Amirkabir University of Technology. ► As one of the key components for the device, the vacuum vessel can provide ultra-high vacuum and clean environment for the plasma operation. ► A limiter is a solid surface which defines the edge of the plasma and designed to protect the wall from the plasma, localizes the plasma–surface interaction and localizes the particle recycling. ► Structural analyses were confirmed by FEM model for dead weight, vacuum pressure and plasma disruptions loads. - Abstract: The Alborz tokamak is a D-shape cross section tokamak that is under construction in Amirkabir University of Technology. At the heart of the tokamak is the vacuum vessel and limiter which collectively are referred to as the vacuum vessel system. As one of the key components for the device, the vacuum vessel can provide ultra-high vacuum and clean environment for the plasma operation. The VV systems need upper and lower vertical ports, horizontal ports and oblique ports for diagnostics, vacuum pumping, gas puffing, and maintenance accesses. A limiter is a solid surface which defines the edge of the plasma and designed to protect the wall from the plasma, localizes the plasma–surface interaction and localizes the particle recycling. Basic structure analyses were confirmed by FEM model for dead weight, vacuum pressure and plasma disruptions loads. Stresses at general part of the VV body are lower than the structure material allowable stress (117 MPa) and this analysis show that the maximum stresses occur near the gravity support, and is about 98 MPa.

  10. Vacuum technology: practical heat treating and brazing

    National Research Council Canada - National Science Library

    Fabian, Roger; Flint, Veronica; Hampson, Suzanne; Levicki, Dawn

    1993-01-01

    ... in 1992, currently he is Vice Chairman of the ASM Technical Division Board, a member of the ASH Heat Treating Steel Panel and Chairman of the Immediate Needs Sub Committee; past Chairman of the ASM Heat Treat Council and Chairman of the Editorial Policy Committee for The Journal of Heat Treating; and Past Chairman of the Hartford Chapter of ASM. Als...

  11. Tailored vacuum chambers for AC magnets

    International Nuclear Information System (INIS)

    Harvey, A.

    1985-01-01

    The proposed LAMPF-II accelerator has a 60-Hz booster synchrotron and a 3-Hz main ring. To provide a vacuum enclosure inside the magnets with low eddycurrent losses and minimal field distortion, yet capable of carrying rf image currents and providing beam stabilization, we propose an innovative combination pipe. Structurally, the enclosure is high-purity alumina ceramic, which is strong, radiation resistant, and has good vacuum properties. Applied to the chamber are thin, spaced, silver conductors using adapted thick-film technology. The conductor design can be tailored to the stabilization requirements, for example, longitudinal conductors for image currents, circumferential for transverse stabilization. The inside of the chamber has a thin, resistive coating to avoid charge build-up. The overall 60-Hz power loss is less than 100 W/m

  12. Tailored vacuum chambers for AC magnets

    International Nuclear Information System (INIS)

    Harvey, A.

    1985-01-01

    The proposed LAMPF-II accelerator has a 60-Hz booster synchrotron and a 3-Hz main ring. To provide a vacuum enclosure inside the magnets with low eddy-current losses and minimal field distortion, yet capable of carrying RF image currents and providing beam stabilization, the authors propose an innovative combination pipe. Structurally, the enclosure is high-purity alumina ceramic, which is strong, radiation resistant, and has good vacuum properties. Applied to the chamber are thin, spaced, silver conductors using adapted thick-film technology. The conductor design can be tailored to the stabilization requirements, for example, longitudinal conductors for image currents, circumferential for transverse stabilization. The inside of the chamber has a thin, resistive coating to avoid charge build-up. The overall 60-Hz power loss is less than 100 W/m

  13. LIGO vacuum system study

    Science.gov (United States)

    Livas, Jeffrey C.; Moore, Boude C.

    1988-01-01

    A laser interferometer gravitational wave observatory (LIGO) is being developed with sensitivities which will have a high probability of detecting gravitational waves from astrophysical sources. A major component of LIGO is a total of 16 km of 1.2 m (48 inch) diameter tube at a pressure of less than 10 to the minus 8th power torr. It will be of 304L stainless steel procured directly from the steel mills with the initial hydrogen content specially reduced. Projections of the outgassing rates of hydrogen and of water vapor as a function of time are given and the uncertainties discussed. Based on these, a preliminary analysis of the vacuum system is presented.

  14. ULTRA HIGH VACUUM VALVE

    Science.gov (United States)

    Fry, W.A.

    1962-05-29

    A valve for high vacuum applications such as the CStellarator where chamber pressures as low as 2 x 10/sup -10/ mm Hg are necessary is designed with a line-of-sight path through the valve for visual inspection of the contents of reactants in such chambers. The valve comprises a turnable resilient metal ball having an aperture therethrough, means for selectively turning the ball to rotate the axis of its line-of-sight path, and soft, deformable opposing orifices that are movable relatively toward said ball to seal with opposite ball surfaces upon said movement of said axis of said line-of-sight path. The valve also includes a bellows seal connected between said orifices and internal actuating means that eliminates the requirement for gasketed turnable valve closing stems. (AEC)

  15. Heterotic vacuum structure

    International Nuclear Information System (INIS)

    Schimmrigk, R.

    1989-01-01

    The vacuum structure of the Heterotic String is investigated. Methods from fleld theory and critical systems are being used to map out part of the moduli space of the (2,2)-configuration space of the Heterotic String. This configuration space breaks up into different Multidimensional spaces, each leading to a different physical particle spectrum. After explicitly constructing parts of the subspace of all (2,2)-vacua corresponding to complete intersection Calabi-Yau manifolds and tensor models of the N = 2 superconformal discrete minimal series, the spectrum of these models is computed and a search for phenomenological viable models is conducted. It turns out that there are only very few such models. In the second part of the thesis the construction of a new threegeneration model is explained and a detailed phenomenological analysis is presented

  16. Accelerator vacuum system elements

    International Nuclear Information System (INIS)

    Sivokon', V.V.; Kobets, A.F.; Shvetsov, V.A.; Sivokon', L.V.

    1980-01-01

    Some elements of vacuum systems are investigated. Considerable attention has been given to the investigation into peculiarities in pumping out of a ionoguide for transportation of an accelerated charged particles beam the spread of which often attains a considerable length. The number of pumps over the ionoguide length is experimentally determined. It is shown that as a result of ionoguide warm-up the pumping out time is considerably reduced maximum permissible pressure is decreased by two orders and lesser rate of pump pumping out is required. The investigations have shown that when operating the ionoguide there is no necessity in setting up seals between the ionoguide and magnetodischarged pump. The causes of the phenomenon in which the pressure near the pump is greater than in the end of the ionoguide, are impurities carried in by the pump into the ionoguide volume and the pumping out capacity of the pressure converter

  17. Researches on Position Detection for Vacuum Switch Electrode

    Science.gov (United States)

    Dong, Huajun; Guo, Yingjie; Li, Jie; Kong, Yihan

    2018-03-01

    Form and transformation character of vacuum arc is important influencing factor on the vacuum switch performance, and the dynamic separations of electrode is the chief effecting factor on the transformation of vacuum arcs forms. Consequently, how to detect the position of electrode to calculate the separations in the arcs image is of great significance. However, gray level distribution of vacuum arcs image isn’t even, the gray level of burning arcs is high, but the gray level of electrode is low, meanwhile, the forms of vacuum arcs changes sharply, the problems above restrict electrode position detection precisely. In this paper, algorithm of detecting electrode position base on vacuum arcs image was proposed. The digital image processing technology was used in vacuum switch arcs image analysis, the upper edge and lower edge were detected respectively, then linear fitting was done using the result of edge detection, the fitting result was the position of electrode, thus, accurate position detection of electrode was realized. From the experimental results, we can see that: algorithm described in this paper detected upper and lower edge of arcs successfully and the position of electrode was obtained through calculation.

  18. Vacuum Alignment with more Flavors

    DEFF Research Database (Denmark)

    Ryttov, Thomas

    2014-01-01

    We study the alignment of the vacuum in gauge theories with $N_f$ Dirac fermions transforming according to a complex representation of the gauge group. The alignment of the vacuum is produced by adding a small mass perturbation to the theory. We study in detail the $N_f=2,3$ and $4$ case. For $N_...

  19. Vacuum Gas Tungsten Arc Welding

    Science.gov (United States)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  20. Detecting leaks in vacuum bags

    Science.gov (United States)

    Carlstrom, E. E.

    1980-01-01

    Small leaks in vacuum bag can be readily detected by eye, using simple chemical reaction: combination of ammonia and acetic acid vapors to produce cloudy white smoke. Technique has been successfully used to test seam integrity and to identify minute pinholes in vacuum bag used in assembly of ceramic-tile heat shield for Space Shuttle Orbiter.

  1. UV-B radiation and photosynthetic irradiance acclimate eggplant for outdoor exposure

    Science.gov (United States)

    Latimer, J. G.; Mitchell, C. A.; Mitchell, G. A.

    1987-01-01

    Treatment of greenhouse-grown eggplant (Solanum melongena L. var. esculentum Nees. 'Burpee's Black Beauty') seedlings with supplemental photosynthetically active radiation from cool-white fluorescent lamps increased growth of plants subsequently transferred outdoors relative to growth of plants that received no supplemental radiation or were shaded to 45% of solar irradiation in the greenhouse before transfer outdoors. Eggplant seedlings transferred outdoors were placed under plastic tarps either to provide relative protection from solar ultraviolet-B (UV-B) radiation (280-315 nm) using Mylar film or to allow exposure to UV-B using cellulose acetate. Protection of seedlings from UV-B radiation resulted in greater leaf expansion than for UV-B-exposed seedlings, but no change in leaf or shoot dry weight occurred after 9 days of treatment. Specific leaf weight increased in response to UV-B exposure outdoors. Exposure of eggplant to UV-B radiation from fluorescent sunlamps in the greenhouse also decreased leaf expansion and leaf and shoot dry weight gain after 5 days of treatment. However, there were no differences in leaf or shoot dry weight relative to control plants after 12 days of UV-B treatment, indicating that UV-B treated plants had acclimated to the treatment and actually had caught up with non-UV-B-irradiated plants in terms of growth.

  2. Pollen sensitivity to ultraviolet-B (UV-B) suggests floral structure evolution in alpine plants.

    Science.gov (United States)

    Zhang, Chan; Yang, Yong-Ping; Duan, Yuan-Wen

    2014-03-31

    Various biotic and abiotic factors are known to exert selection pressures on floral traits, but the influence of ultraviolet-B (UV-B) light on the evolution of flower structure remains relatively unexplored. We have examined the effectiveness of flower structure in blocking radiation and the effects of UV-B on pollen viability in 42 species of alpine plants in the Hengduan Mountains, China. Floral forms were categorized as either protecting or exposing pollen grains to UV-B. The floral materials of plants with exposed and protected pollen grains were able to block UV-B at similar levels. Exposure to UV-B radiation in vitro resulted in a significantly greater loss of viability in pollen from plant species with protective floral structures. The pronounced sensitivity of protected pollen to UV-B radiation was associated with the type of flower structure. These findings demonstrate that UV-B plays an important role in the evolution of protective floral forms in alpine plants.

  3. Inhibitory effects of dietary Spirulina platensis on UVB-induced skin inflammatory responses and carcinogenesis.

    Science.gov (United States)

    Yogianti, Flandiana; Kunisada, Makoto; Nakano, Eiji; Ono, Ryusuke; Sakumi, Kunihiko; Oka, Sugako; Nakabeppu, Yusaku; Nishigori, Chikako

    2014-10-01

    Reactive oxygen species produced in response to UVR are important in skin tumor development. We have previously reported that deficiency of the Ogg1 gene, encoding the repair enzyme for 8-oxo-7,8-dihydroguanine (8-oxoG), increases skin tumor incidence in mice upon repetitive UVB exposure and modulation of UVB-induced inflammatory response. Spirulina platensis is used as a human food supplement because it contains abundant nutritional and antioxidant components. Therefore, we investigated the inhibitory effects of S. platensis on UVB-induced skin tumor development in Ogg1 knockout-(KO) mice and the wild-type (WT) counterpart. Dietary S. platensis suppressed tumor induction and development in both genotypes compared with our previous data without S. platensis. Induction of erythema and ear swelling, one of the hallmarks of UVB-induced inflammatory responses, was suppressed in the skin of Ogg1-KO mice and albino hairless mice fed with dietary S. platensis. Compared with untreated mice, S. platensis-administered mice showed significantly reduced 8-oxoG formation in the skin after UVB exposure. Moreover, we found that S. platensis effectively downregulated the signal proteins p38 mitogen-activated protein kinase, stress-activated protein kinase/c-Jun N-terminal kinase, and extracellular signal-regulated kinase after UVB exposure especially in Ogg1-KO mice. Our results suggest that S. platensis exerts antitumor effects against UVB irradiation in the skin through its anti-inflammatory and antioxidant effects.

  4. Cosmology with decaying vacuum energy

    International Nuclear Information System (INIS)

    Freese, K.; Adams, F.; Frieman, J.; Mottola, E.

    1987-09-01

    Motivated by recent attempts to solve the cosmological constant problem, we examine the observational consequences of a vacuum energy density which decays in time. For all times later than t ∼ 1 sec, the ratio of the vacuum to the total energy density of the universe must be small. Although the vacuum cannot provide the ''missing mass'' required to close the universe today, its presence earlier in the history of the universe could have important consequences. We discuss restrictions on the vacuum energy arising from primordial nucleosynthesis, the microwave and gamma ray background spectra, and galaxy formation. A small vacuum component at the era of nucleosynthesis, 0.01 5, but in some cases would severely distort the microwave spectrum. 9 refs., 3 figs

  5. Hadron Contribution to Vacuum Polarisation

    CERN Document Server

    Davier, M; Malaescu, B; Zhang, Z

    2016-01-01

    Precision tests of the Standard Theory require theoretical predictions taking into account higher-order quantum corrections. Among these vacuum polarisation plays a predominant role. Vacuum polarisation originates from creation and annihilation of virtual particle–antiparticle states. Leptonic vacuum polarisation can be computed from quantum electrodynamics. Hadronic vacuum polarisation cannot because of the non-perturbative nature of QCD at low energy. The problem is remedied by establishing dispersion relations involving experimental data on the cross section for e+ e− annihilation into hadrons. This chapter sets the theoretical and experimental scene and reviews the progress achieved in the last decades thanks to more precise and complete data sets. Among the various applications of hadronic vacuum polarisation calculations, two are emphasised: the contribution to the anomalous magnetic moment of the muon, and the running of the fine structure constant α to the Z mass scale. They are fundamental ingre...

  6. Vacuum transitions in dual models

    International Nuclear Information System (INIS)

    Pashnev, A.I.; Volkov, D.V.; Zheltukhin, A.A.

    1976-01-01

    The investigation is continued of the spontaneous vacuum transition problem in the Neview-Schwartz dual model (NSDM). It is shown that vacuum transitions allow disclosing of supplementary degeneration in the resonance state spectrum. The dual amplitudes possess an internal structure corresponding to the presence of an infinite number of quarks with increasing masses and retained charges. The Adler principle holds. Analytic continuation on the constant of induced vacuum transitions makes it possible to establish the existence of spontaneous vacuum transitions in the NSDM. The consequence of this fact is the exact SU(2) symmetry of π, rho meson trajectories and the Higgs mechanism in the model. In this case the ratios of masses of particles leading trajectories are analogous to those obtained in the current algebra. It is shown that in the NSDM there arises chiral SU(2) x SU(2) x U(1) x U(1) x ... symmetry resulting from spontaneous vacuum transitions

  7. The effects of UV-B radiation on European heathland species

    International Nuclear Information System (INIS)

    Björn, L.O.; Callaghan, T.V.; Johnsen, I.; Lee, J.A.; Manetas, Y.; Paul, N.D.; Sonesson, M.; Wellburn, A.R.; Coop, D.; Heide-Jørgensen, H.S.; Gehrke, C.; Gwynn-Jones, D.; Johanson, U.; Kyparissis, A.; Levizou, E.; Nikolopoulos, D.; Petropoulou, Y.; Stephanou, M.

    1997-01-01

    The effects of enhanced UV-B radiation on three examples of European shrub-dominated vegetation were studied in situ. The experiments were in High Arctic Greenland, northern Sweden and Greece, and at all sites investigated the interaction of enhanced UV-B radiation (simulating a 15% reduction in the ozone layer) with artificially increased precipitation. The Swedish experiment also involved a study of the interaction between enhanced UV-B radiation and elevated CO 2 (600 ppm). These field studies were supported by an outdoor controlled environment study in the United Kingdom involving modulated enhancement of UV-B radiation in combination with elevated CO 2 (700 ppm). Effects of the treatments on plant growth, morphology, phenology and physiology were measured. The effects observed were species specific, and included both positive and negative responses to the treatments. In general the negative responses to UV-B treatments of up to three growing seasons were small, but included reductions in shoot growth and premature leaf senescence. Positive responses included a marked increase in flowering in some species and a stimulation of some photosynthetic processes. UV-B treatment enhanced the drought tolerance of Pinus pinea and Pinus halepensis by increasing leaf cuticle thickness. In general, there were few interactions between the elevated CO 2 and enhanced UV-B treatments. There was evidence to suggest that although the negative responses to the treatments were small, damage may be increasing with time in some long-lived woody perennials. There was also evidence in the third year of treatments for effects of UV-B on insect herbivory in Vaccinium species. The experiments point to the necessity for long-term field investigations to predict the likely ecological consequences of increasing UV-B radiation. (author)

  8. Voriconazole N-oxide and its UVB photoproduct sensitize keratinocytes to UVA

    Science.gov (United States)

    Ona-Vu, K.; Oh, D.H.

    2015-01-01

    Background The antifungal agent, voriconazole, is associated with phototoxicity and photocarcinogenicity. Prior work has indicated that voriconazole and its hepatic N-oxide metabolite do not sensitize keratinocytes to ultraviolet B (UVB). Clinical observations have suggested ultraviolet A (UVA) may be involved. Objectives To determine the photochemistry and photobiology of voriconazole and its major hepatic metabolite, voriconazole N-oxide. Methods Voriconazole and voriconazole N-oxide were spectrophotometrically monitored following various doses of UVB. Cultured human keratinocytes were treated with parental drugs or with their UVB photoproducts, and survival following UVA irradiation was measured by thiazolyl blue metabolism. Reactive oxygen species and 8-oxoguanine were monitored by fluorescence microscopy. Results Voriconazole and voriconazole N-oxide have varying ultraviolet B (UVB) absorption but do not acutely sensitize cultured human keratinocytes following UVB exposure. However, sustained UVB exposures produced notable dose- and solvent-dependent changes in the absorption spectra of voriconazole N-oxide which in aqueous solution acquires a prominent ultraviolet A (UVA) absorption band, suggesting formation of a discrete photoproduct. Neither the parental drugs nor their photoproducts sensitized cells to UVB though all but voriconazole N-oxide were moderately toxic to cells in the dark. Notably, both voriconazole N-oxide and its UVB photoproduct, but not voriconazole or its photoproduct, additionally sensitized cells to UVA by >3-fold relative to controls in association with UVA-induced reactive oxygen species and 8-oxoguanine levels. Conclusions Voriconazole N-oxide and its UVB-photoproduct act as UVA-sensitizers that generate reactive oxygen species and that produce oxidative DNA damage. These results suggest a mechanism for the phototoxicity and photocarcinogenicity observed with voriconazole treatment. PMID:25919127

  9. UV-B induction of the E3 ligase ARIADNE12 depends on CONSTITUTIVELY PHOTOMORPHOGENIC 1.

    Science.gov (United States)

    Xie, Lisi; Lang-Mladek, Christina; Richter, Julia; Nigam, Neha; Hauser, Marie-Theres

    2015-08-01

    The UV-B inducible ARIADNE12 (ARI12) gene of Arabidopsis thaliana is a member of the RING-between-RING (RBR) family of E3 ubiquitin ligases for which a novel ubiquitination mechanism was identified in mammalian homologs. This RING-HECT hybrid mechanism needs a conserved cysteine which is replaced by serine in ARI12 and might affect the E3 ubiquitin ligase activity. We have shown that under photomorphogenic UV-B, ARI12 is a downstream target of the classical ultraviolet B (UV-B) UV Resistance Locus 8 (UVR8) pathway. However, under high fluence rate of UV-B ARI12 was induced independently of UVR8 and the UV-A/blue light and red/far-red photoreceptors. A key component of several light signaling pathways is Constitutively Photomorphogenic 1 (COP1). Upon UV-B COP1 is trapped in the nucleus through interaction with UVR8 permitting the activation of genes that regulate the biosynthesis of UV-B protective metabolites and growth adaptations. To clarify the role of COP1 in the regulation of ARI12 mRNA expression and ARI12 protein stability, localization and interaction with COP1 was assessed with and without UV-B. We found that COP1 controls ARI12 in white light, low and high fluence rate of UV-B. Furthermore we show that ARI12 is indeed an E3 ubiquitin ligase which is mono-ubiquitinated, a prerequisite for the RING-HECT hybrid mechanism. Finally, genetic analyses with transgenes expressing a genomic pmARI12:ARI12-GFP construct confirm the epistatic interaction between COP1 and ARI12 in growth responses to high fluence rate UV-B. Copyright © 2015 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

  10. Effects of Enhanced UV-B Radiation on Biochemical Traits in Postharvest Flowers of Medicinal Chrysanthemum.

    Science.gov (United States)

    Si, Chao; Yao, Xiao-Qin; He, Xue-Li; Chu, Jian-Zhou; Ma, Chun-Hui; Shi, Xiao-Fei

    2015-01-01

    This article reported UV-B radiation effects on biochemical traits in postharvest flowers of chrysanthemum. The experiment included six levels of UV-B radiation (UV0, 0 μW cm(-2); UV50, 50 μW cm(-2); UV200, 200 μW cm(-2); UV400, 400 μW cm(-2); UV600, 600 μW cm(-2) and UV800, 800 μW cm(-2). Enhanced UV-B radiation significantly increased hydrogen peroxide content (except for UV50), but did not evidently affect malondialdehyde content in flowers. Chlorophyll b and total chlorophyll content were significantly increased by UV600 and UV800. UV400 and UV600 significantly increased anthocyanins, carotenoids and UV-B absorbing compounds content, and the activities of phenylalanine ammonia lyase (PAL) and cinnamic acid-4-hydroxylase (C4H) over the control. 4-coumarate CoA ligase (4CL) activity was significantly decreased by enhanced UV-B radiation (except for UV50). The relationships between UV-B radiation intensities and the activities of secondary metabolism enzymes were best described by a second-order polynomial. The R(2) values for UV-B radiation intensities and the activities of PAL, C4H and 4CL were 0.8361, 0.5437 and 0.8025, respectively. The results indicated that enhanced UV-B radiation could promote secondary metabolism processes in postharvest flowers, which might be beneficial for the accumulation of medically active ingredients in medicinal plants. The optimal UV-B radiation intensities in the study were between UV400-UV600. © 2015 The American Society of Photobiology.

  11. Short- and long-term physiological responses of grapevine leaves to UV-B radiation.

    Science.gov (United States)

    Martínez-Lüscher, J; Morales, F; Delrot, S; Sánchez-Díaz, M; Gomés, E; Aguirreolea, J; Pascual, I

    2013-12-01

    The present study aimed at evaluating the short- and long-term effects of UV-B radiation on leaves of grapevine Vitis vinifera (cv. Tempranillo). Grapevine fruit-bearing cuttings were exposed to two doses of supplemental biologically effective UV-B radiation (UV-BBE) under glasshouse-controlled conditions: 5.98 and 9.66kJm(-2)d(-1). The treatments were applied either for 20d (from mid-veraison to ripeness) or 75d (from fruit set to ripeness). A 0kJm(-2)d(-1) UV-B treatment was included as control. The main effects of UV-B were observed after the short-term exposure (20d) to 9.66kJm(-2)d(-1). Significant decreases in net photosynthesis, stomatal conductance, sub-stomatal CO2 concentration, the actual photosystem II (PSII) efficiency, total soluble proteins and de-epoxidation state of the VAZ cycle were observed, whereas the activities of several antioxidant enzymes increased significantly. UV-B did not markedly affect dark respiration, photorespiration, the maximum potential PSII efficiency (Fv/Fm), non-photochemical quenching (NPQ), as well as the intrinsic PSII efficiency. However, after 75d of exposure to 5.98and 9.66kJm(-2)d(-1) UV-B most photosynthetic and biochemical variables were unaffected and there were no sign of oxidative damage in leaves. The results suggest a high long-term acclimation capacity of grapevine to high UV-B levels, associated with a high accumulation of UV-B absorbing compounds in leaves, whereas plants seemed to be tolerant to moderate doses of UV-B. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  12. Vacuum deposition onto webs, films and foils

    CERN Document Server

    Bishop, Charles A

    2011-01-01

    Roll-to-roll vacuum deposition is the technology that applies an even coating to a flexible material that can be held on a roll and provides a much faster and cheaper method of bulk coating than deposition onto single pieces or non-flexible surfaces, such as glass. This technology has been used in industrial-scale applications for some time, including a wide range of metalized packaging (e.g. snack packets). Its potential as a high-speed, scalable process has seen an increasing range of new products emerging that employ this cost-effective technology: solar energy products are moving from rigid panels onto flexible substrates, which are cheaper and more versatile; in a similar way, electronic circuit 'boards' can be produced on a flexible polymer, creating a new range of 'flexible electronics' products; and, flexible displays are another area of new technology in vacuum coating, with flexible display panels and light sources emerging. Charles Bishop has written this book to meet the need he identified, as a t...

  13. 49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Vacuum brake assist unit and vacuum brake system... Vehicles With GVWR of More Than 10,000 Pounds § 570.56 Vacuum brake assist unit and vacuum brake system. The following requirements apply to vehicles with vacuum brake assist units and vacuum brake systems...

  14. Vacuum nanoelectronic devices novel electron sources and applications

    CERN Document Server

    Evtukh, Anatoliy; Yilmazoglu, Oktay; Mimura, Hidenori; Pavlidis, Dimitris

    2015-01-01

    Introducing up-to-date coverage of research in electron field emission from nanostructures, Vacuum Nanoelectronic Devices outlines the physics of quantum nanostructures, basic principles of electron field emission, and vacuum nanoelectronic devices operation, and offers as insight state-of-the-art and future researches and developments.  This book also evaluates the results of research and development of novel quantum electron sources that will determine the future development of vacuum nanoelectronics. Further to this, the influence of quantum mechanical effects on high frequency vacuum nanoelectronic devices is also assessed. Key features: In-depth description and analysis of the fundamentals of Quantum Electron effects in novel electron sources. Comprehensive and up-to-date summary of the physics and technologies for THz sources for students of physical and engineering specialties and electronics engineers. Unique coverage of quantum physical results for electron-field emission and novel electron sourc...

  15. Application of high power microwave vacuum electron devices

    International Nuclear Information System (INIS)

    Ding Yaogen; Liu Pukun; Zhang Zhaochuan; Wang Yong; Shen Bin

    2011-01-01

    High power microwave vacuum electron devices can work at high frequency, high peak and average power. They have been widely used in military and civil microwave electron systems, such as radar, communication,countermeasure, TV broadcast, particle accelerators, plasma heating devices of fusion, microwave sensing and microwave heating. In scientific research, high power microwave vacuum electron devices are used mainly on high energy particle accelerator and fusion research. The devices include high peak power klystron, CW and long pulse high power klystron, multi-beam klystron,and high power gyrotron. In national economy, high power microwave vacuum electron devices are used mainly on weather and navigation radar, medical and radiation accelerator, TV broadcast and communication system. The devices include high power pulse and CW klystron, extended interaction klystron, traveling wave tube (TWT), magnetron and induced output tube (IOT). The state of art, common technology problems and trends of high power microwave vacuum electron devices are introduced in this paper. (authors)

  16. Automatic electromagnetic valve for previous vacuum

    International Nuclear Information System (INIS)

    Granados, C. E.; Martin, F.

    1959-01-01

    A valve which permits the maintenance of an installation vacuum when electric current fails is described. It also lets the air in the previous vacuum bomb to prevent the oil ascending in the vacuum tubes. (Author)

  17. Vacuum type D initial data

    Science.gov (United States)

    García-Parrado Gómez-Lobo, Alfonso

    2016-09-01

    A vacuum type D initial data set is a vacuum initial data set of the Einstein field equations whose data development contains a region where the space–time is of Petrov type D. In this paper we give a systematic characterisation of a vacuum type D initial data set. By systematic we mean that the only quantities involved are those appearing in the vacuum constraints, namely the first fundamental form (Riemannian metric) and the second fundamental form. Our characterisation is a set of conditions consisting of the vacuum constraints and some additional differential equations for the first and second fundamental forms These conditions can be regarded as a system of partial differential equations on a Riemannian manifold and the solutions of the system contain all possible regular vacuum type D initial data sets. As an application we particularise our conditions for the case of vacuum data whose data development is a subset of the Kerr solution. This has applications in the formulation of the nonlinear stability problem of the Kerr black hole.

  18. HIGH TEMPERATURE VACUUM MIXER

    Directory of Open Access Journals (Sweden)

    E. D. Chertov

    2015-01-01

    Full Text Available The work is devoted to the creation of a new type of mixer to produce homogeneous mixtures of dissimilar materials applied to recycling of housing and communal services waste. The article describes the design of a dual-chamber device of the original high-temperature vacuum mixer, there investigated the processes occurring in the chambers of such devices. The results of theoretical and experimental research of the process of mixing recycled polyethylene with a mixture of "grinded food waste – Eco wool” are presented. The problem of the optimum choice of bending the curvilinear blades in the working volume of the seal, which is achieved by setting their profile in the form of involute arc of several circles of different radii, is examined . The dependences, allowing to define the limits of the changes of the main mode parameters the angular velocity of rotation of the working body of the mixer using two ways of setting the profile of the curvilinear blade mixer are obtained. Represented design of the mixer is proposed to use for a wide range of tasks associated with the mixing of the components with a strongly pronounced difference of physic al chemical properties and, in particular, in the production of composites out of housing and communal services waste.

  19. Changing MFTF vacuum environment

    International Nuclear Information System (INIS)

    Margolies, D.; Valby, L.

    1982-01-01

    The Mirror Fusion Test Facility (MFTF) vaccum vessel will be about 60m long and 10m in diameter at the widest point. The allowable operating densities range from 2 x 10 9 to 5 x 10 10 particles per cc. The maximum leak rate of 10 -6 tl/sec is dominated during operation by the deliberately injected cold gas of 250 tl/sec. This gas is pumped by over 1000 square meters of cryopanels, external sorbtion pumps and getters. The design and requirements have changed radically over the past several years, and they are still not in final form. The vacuum system design has also changed, but more slowly and less radically. This paper discusses the engineering effort necessary to meet these stringent and changing requirements. Much of the analysis of the internal systems has been carried out using a 3-D Monte Carlo computer code, which can estimate time dependent operational pressures. This code and its use will also be described

  20. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-10-27

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

  1. The effects of different UV-B radiation intensities on morphological and biochemical characteristics in Ocimum basilicum L.

    Science.gov (United States)

    Sakalauskaitė, Jurga; Viskelis, Pranas; Dambrauskienė, Edita; Sakalauskienė, Sandra; Samuolienė, Giedrė; Brazaitytė, Aušra; Duchovskis, Pavelas; Urbonavičienė, Dalia

    2013-04-01

    The effects of short-term ultraviolet B (UV-B) irradiation on sweet basil (Ocimum basilicum L. cv. Cinnamon) plants at the 3-4 leaf pair and flowering stages were examined in controlled environment growth chambers. Plants were exposed to 0 (reference), 2 and 4 kJ UV-B m(-2) day(-1) over 7 days. Exposure of basil plants to supplementary UV-B light resulted in increased assimilating leaf area, fresh biomass and dry biomass. Stimulation of physiological functions in young basil plants under either applied UV-B dose resulted in increased total chlorophyll content but no marked variation in carotenoid content. At the flowering stage the chlorophyll and carotenoid contents of basil were affected by supplementary UV-B radiation, decreasing with enhanced UV-B exposure. Both total antioxidant activity (2,2-diphenyl-1-picrylhydrazyl free radical assay) and total phenolic compound content were increased by UV-B light supplementation. Young and mature basil plants differed in their ascorbic acid content, which was dependent on UV-B dose and plant age. UV-B radiation resulted in decreased nitrate content in young basil plants (3-4 leaf pair stage). These results indicate that the application of short-exposure UV-B radiation beneficially influenced both growth parameters and biochemical constituents in young and mature basil plants. © 2012 Society of Chemical Industry.

  2. Effects of UV-B irradiation on isoforms of antioxidant enzymes and their activities in red alga Grateloupia filicina (Rhodophyta)

    Science.gov (United States)

    Zhao, Jiqiang; Li, Lixia

    2014-11-01

    Macroalgae in a littoral zone are inevitably exposed to UV-B irradiance. We analyzed the effects of UV-B on isoenzyme patterns and activities of superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX) of red algae Grateloupia filicina (Lamour.) C. Agardh. The activities of SOD, CAT, and APX changed in response to UV-B in a time- and dose-dependent manner. POX activity increased significantly under all three UV-B treatments. The enzymatic assay showed three distinct bands of SODI (Mn-SOD), SODII (Fe-SOD), and SODIII (CuZn-SOD) under a low (Luv) and medium (Muv) dose of UV-B irradiation, while SODI and SODIII activities decreased significantly when exposed to a high dose of UV-B irradiation (Huv). The activity of POX isoenzymes increased significantly after exposure to UV-B, which is consistent with the total activity. In addition, a clear decrease in activity of CATIV was detected in response to all the three doses of UV treatments. Some bands of APX isoenzyme were also clearly influenced by UV-B irradiation. Correspondingly, the daily growth rate declined under all the three exposure doses, and was especially significant under Muv and Huv treatments. These data suggest that, although the protection mechanisms of antioxidant defense system are partly inducible by UV-B to prevent the damage, G. filicina has incomplete tolerance to higher UV-B irradiation stress.

  3. The preventive effect of linalool on acute and chronic UVB-mediated skin carcinogenesis in Swiss albino mice.

    Science.gov (United States)

    Gunaseelan, Srithar; Balupillai, Agilan; Govindasamy, Kanimozhi; Muthusamy, Ganesan; Ramasamy, Karthikeyan; Shanmugam, Mohana; Prasad, N Rajendra

    2016-07-06

    In this study, we evaluated the role of linalool in acute ultraviolet-B (UVB; 280-320 nm) radiation-induced inflammation and chronic UVB-mediated photocarcinogenesis in mouse skin. Acute UVB-irradiation (180 mJ cm(-2)) causes hyperplasia, edema formation, lipid peroxidation, antioxidant depletion, and overexpression of cyclooxygenase-2 (COX-2) and ornithine decarboxylase (ODC) in mouse skin. Topical or intraperitoneal (i.p.) treatment of linalool prevented acute UVB-induced hyperplasia, edema formation, lipid peroxidation, and antioxidant depletion in mouse skin. Further, linalool treatment prevented UVB-induced overexpression of COX-2 and ODC in mouse skin. In the chronic study, mice were subjected to UVB-exposure thrice weekly for 30 weeks. Chronic UVB-exposure induced tumor incidence and expression of proliferative markers such as NF-κB, TNF-α, IL-6, COX-2, VEGF, TGF-β1, Bcl-2 and mutated p53 in mouse skin. Treatment with linalool before each UVB-exposure significantly prevented the expression of these proliferative markers and subsequently decreased the tumor incidence in mice skin. Histopathological studies confirmed the development of dysplasia and squamous cell carcinoma (SCC) in the chronic UVB-exposed mouse skin; and this was prevented by both topical and i.p. linalool treatment. Therefore, linalool may be considered as a photochemopreventive agent against UVB radiation induced skin carcinogenesis.

  4. Influence of uvA on the erythematogenic and therapeutic effects of uvB irradiation in psoriasis; photoaugmentation effects

    International Nuclear Information System (INIS)

    Boer, J.; Schothorst, A.A.; Suurmond, D.

    1981-01-01

    The effect of repeated exposure to an additive dose of long ultraviolet (uvA) radiation on the erythemogenic and therapeutic effects of middle ultraviolet (uvB) irradiation was investigated in 8 patients with psoriasis. The surface of the backs of these patients was divided into 2 parts, 1 of which received only uvB irradiation 4 times a week and the other uvA + uvB. uvB was provided by Philips TL-12 lamps and uvA by glass-filtered Philips TL-09 lamps. uvA was held constantly at 10 J/cm2, whereas uvB alone were evaluated by 4 tests during the treatment to determine the minimal erythema dose (MED). Test I (at the start of the therapy) showed a photoaugmentative effect which was no longer apparent in Test III (third week). Test III showed a reversal of the ratios of the MEDs of the sites irradiated with the uvA + uvB and uvB (MED A + B/MED B). This is ascribed to the marked pigmentation which appeared after repeated irradiation with the uvA + uvB combination. Comparison showed for the improvement of the psoriasis no distinct differences between uvA + uvB irradiation and uvB alone, but the former had the cosmetic advantage of giving pleasing tan

  5. Vacuum system for HIMAC synchrotrons

    International Nuclear Information System (INIS)

    Kanazawa, M.; Sudou, M.; Sato, K.

    1994-01-01

    HIMAC synchrotrons are now under construction, which require vacuum chambers of large aperture and high vacuum of about 10 -9 torr. Wide thin wall vacuum chamber of 0.3 mm thickness reinforced with ribs has been developed as the chamber at dipole magnet. We have just now started to evacuate the lower ring. The obtained average value was about 5x10 -8 torr with turbo-molecular and sputter ion pumps, and 1.1x10 -9 torr after baking. (author)

  6. Resistor cooling in a vacuum

    International Nuclear Information System (INIS)

    Crittenden, R.; Krider, J.

    1987-01-01

    This note describes thermal measurements which were done on a resistor operating both in air at one atmosphere pressure and in a vacuum of a few milliTorr. The motivation for this measurement was our interest in operating a BGO crystal-photomultiplier tube-base assembly in a vacuum, as a synchrotron radiation detector to tag electrons in the MT beam. We wished to determine what fraction of the total resistor power was dissipated by convection in air, in order to know whether there would be excessive heating of the detector assembly in a vacuum. 3 figs

  7. Experimental tests of vacuum energy

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    While the current vacuum energy of the Universe is very small, in our standard cosmological picture it has been much larger at earlier epochs. We try to address the question of what are possible ways to try to experimentally verify this. One direction is to look for systems where vacuum energy constitutes a non-negligible fraction of the total energy, and study the properties of those. Another possibility is to focus on the epochs around cosmic phase transitions, when the vacuum energy is of the same order as the total energy. Along these lines we investigate properties of neutron stars and the imprint of phase transitions on primordial gravitational waves.

  8. Vacuum vessel for thermonuclear device

    International Nuclear Information System (INIS)

    Hagiwara, Koji; Imura, Yasuya.

    1979-01-01

    Purpose: To provide constituted method for easily performing baking of vacuum vessel, using short-circuiting segments. Constitution: At the time of baking, one turn circuit is formed by the vacuum vessel and short-circuiting segments, and current transformer converting the one turn circuit into a secondary circuit by the primary coil and iron core is formed, and the vacuum vessel is Joule heated by an induction current from the primary coil. After completion of baking, the short-circuiting segments are removed. (Kamimura, M.)

  9. Vacuum chamber 'bicone'

    CERN Multimedia

    1977-01-01

    This chamber is now in the National Museum of History and Technology, Smithsonian Institution, Washington, DC, USA, where it was exposed in an exhibit on the History of High Energy Accelerators (1977).

  10. Effects of UV-B irradiation on photomovement in the desmid, Cosmarium cucumis

    International Nuclear Information System (INIS)

    Haeder, D.-P.

    1987-01-01

    Monochromatic UV-B irradiation affects neither the absorption nor the fluorescence of the bulk pigments in the desmid Cosmarium cucumis but it impairs photomovement of these organisms at fluence rates which are not higher than the ambient level of solar UV-B irradiation. Photoaccumulations and phototaxis are strongly inhibited especially at wavelengths <= 300 nm while photodispersal at higher white light fluence rates is hardly affected by supplementary UV-B. This effect has important consequences for the growth and survival of populations in their natural environment: these photosynthetic organisms utilize photomovement to find and stay in areas of suitable visible light fluence rates. The UV-B component of solar irradiation both impairs the strategy of the organisms to find a suitable position and the escape mechanism by which the cells move out of areas with too strong white illuminances which photooxidize the bulk pigments and bleach the population within a few days. (author)

  11. Changes in epicuticular flavonoids and photosynthetic pigments as a plant response to UV-B radiation

    International Nuclear Information System (INIS)

    Cuadra, P.; Harborne, J.B.

    1996-01-01

    Treatment of Gnaphalium vira-vira plants with UV-B radiation caused changes in plant growth and in plant chemistry. The leaf surface contained two O-methylated flavones, araneol and 7-O-methylaraneol. HPLC analysis showed that 20 days of UV-B radiation increased the synthesis of 7-O-methylaraneol at the expense of araneol. Spectrophotometric analysis of the photosynthetic pigments showed that UV-B radiation also increases the pigment content in treated plants. Another U V alteration is epidermal hair damage, as observed in SEM pictures of treated leaves. This combination of physiological and phytochemical effects may be interpreted as a plant response to UV-B stress

  12. [Allelopathic effect of Corallina pilulifera on Heterosigma akashiwo and its responses to UV-B irradiation].

    Science.gov (United States)

    Zhao, Yan; Yu, Qing-Yun; Zhou, Bin; Ju, Qing; Tang, Xue-Xi

    2009-10-01

    By the method of co-culture and using cell density as the main indicator, this paper studied the allelopathic effect of Corallina pilulifera on Heterosigma akashiwo and its responses to UV-B irradiation. Under normal condition, the fresh tissue and aqueous extracts of C. pilulifera had significant inhibitory effects on the growth of H. akashiwo (P 0.05). After pre-treated with different dose UV-B radiation and then co-cultured with H. akashiwo, C. pilulifera had some changes in the allelopathic activity of its fresh tissue, dry powder, and aqueous extracts. High-dose UV-B radiation (3.0 J x m(-2)) induced the decrease of the allelopathic effect, whereas low-dose UV-B radiation (0.9 J x m(-2)) was in adverse (P < 0.05).

  13. [Responses of enzymes in terrestrial plants to enhanced UV-B radiation].

    Science.gov (United States)

    Yao, Xiaoqin; Liu, Qing

    2006-05-01

    With the destruction of ozone layer, ultraviolet-B (UV-B, 280 to approximately 320nm) radiation has being enhanced at the earth's surface. The energy of UV-B irradiation is far higher than that of visible light, which could be absorbed by biomacromolecules such as protein and nuclei acid. Enzyme is a sort of protein catalyzing the biochemical processes, and its content and activity in plant have strong responses to enhanced UV-B radiation. This paper summarized the research advances in the effects of enhanced UV-B radiation on the key enzymes, mainly including antioxidant enzymes, ribulose-1, 5-diphosphoscarboxylase, nitrate reductase and glutamine synthetase in terrestrial plants. Some suggestions for future research in this field were put forward.

  14. Response of hoary alyssum (Berteroa incana L. to UV-B radiation

    Directory of Open Access Journals (Sweden)

    Agnieszka Stokłosa

    2012-12-01

    Full Text Available This greenhouse experiment evaluated the response of hoary alyssum plants, up to the rosette phase, to different levels of UV-B radiation. The experiment was carried out in the chambers, equipped with UV-B lamps, emitting biologically effective UV-B radiation of 0 (control, 4, 6 or 8 kJ. As a result, specific traits of the plants such as: leaf number, lamina length, leaf area, specific leaf weight, relative chlorophyll content and shoot biomass were unaffected by any of the UV-B treatments. Significant reductions in the share of large leaves, leaf stalk length and root biomass were noted for plants growing under 8 kJ UV-BBE.

  15. The UV-B Photoreceptor UVR8: From Structure to Physiology

    Science.gov (United States)

    Jenkins, Gareth I.

    2014-01-01

    Low doses of UV-B light (280 to 315 nm) elicit photomorphogenic responses in plants that modify biochemical composition, photosynthetic competence, morphogenesis, and defense. UV RESISTANCE LOCUS8 (UVR8) mediates photomorphogenic responses to UV-B by regulating transcription of a set of target genes. UVR8 differs from other known photoreceptors in that it uses specific Trp amino acids instead of a prosthetic chromophore for light absorption during UV-B photoreception. Absorption of UV-B dissociates the UVR8 dimer into monomers, initiating signal transduction through interaction with CONSTITUTIVELY PHOTOMORPHOGENIC1. However, much remains to be learned about the physiological role of UVR8 and its interaction with other signaling pathways, the molecular mechanism of UVR8 photoreception, how the UVR8 protein initiates signaling, how it is regulated, and how UVR8 regulates transcription of its target genes. PMID:24481075

  16. Effects of enhanced UVB on growth and yield of alfalfa and soybean under field conditions

    International Nuclear Information System (INIS)

    Al-Oudat, M.; Baydon, S.A.; Mohamad, A.

    1998-01-01

    The effects of 20% increase of UVB on growth and yield of alfalfa (Medicago Sativa L.) and two cultivars of soybean (Glycine Max (L.) Mer) under field conditions have been investigated. The increase of UVB dose ranged between 1.746 and 7.112 J/cm 2 during experiment. The results showed that soybean yield decrease by 16% and 31% in A. 3803 and A. 2522 cultivars respectively, under UVB exposure. The dry weight and leaf area were sensitive in the A. 3803 cultivar, while they were tolerant in the A. 2522 cultivar. Alfalfa response to UVB varied during the different stages of growth, whereas the yield was 12% less in the exposed plants. (author)

  17. UVB-Protective Effects of Isoflavone Extracts from Soybean Cake in Human Keratinocytes

    Directory of Open Access Journals (Sweden)

    Chi-Feng Hung

    2007-07-01

    Full Text Available It has been shown by chromatography that aglycone, glucoside, acetylglucosideand malonylglucoside isoflavone extracts prepared from soybean cake showed betterantioxidant activities than isoflavone standards. Consequently, the aim of this study was toevaluate the protective effects of these isoflavone extracts against ultraviolet B (UVB-induced keratinocyte damage. Our results demonstrated that these soybean cake isoflavoneextracts could inhibit UVB-induced keratinocyte death. Moreover, they could inhibit UVB-induced intracellular release of hydrogen peroxide (H2O2 Furthermore, these isoflavoneextracts differentially inhibited UVB-induced MAPK phosphorylation. The ERK1/2 andp38 phosphorylation was not inhibited by all tested isoflavone extracts, whereas JNKphosphorylation was inhibited by group I to group III isoflavone extracts. Since theseisoflavone extracts are relative stable and easily obtained than the isoflavone standards, wesuggest that soybean cake may be a useful potential source for developing effective skincare agents in against photoaging.

  18. COMPARATIVE ANALYSIS OF UV-C AND UV-B RADIATION INFLUENCE ON PLANT OBJECTS

    Directory of Open Access Journals (Sweden)

    О. Міхєєв

    2011-04-01

    Full Text Available General aim of work – comparative research of temporal regularities of growth processes of pea,that was grown under normal conditions and with application of UV-C and UV-B irradiation ofstem part, and also detection of irradiation dose relations to parameter of root and stem part sproutsgrowth rate of Aronis pea. Research subject of UV-C and UV-B irradiation influence on dynamicsof plant growth parameters in each set of experiments was alteration of growth rate, pecularities ofgrowth dynamics in different conditions of experiment, detection of UV-C and UV-B irradiationdoses range, that stimulate or inhibit growth parameters of pea sprouts. The investigation resulted indetermination 1,3 times higher efficiency of UV-V irradiation comparing to UV-B irradiation.Reaction of root didn’t depend on the type of UV-radiation

  19. LTC vacuum blasting machine (concrete): Baseline report

    International Nuclear Information System (INIS)

    1997-01-01

    The LTC shot blast technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU's evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The LTC 1073 Vacuum Blasting Machine uses a high-capacity, direct-pressure blasting system which incorporates a continuous feed for the blast media. The blast media cleans the surface within the contained brush area of the blast. It incorporates a vacuum system which removes dust and debris from the surface as it is blasted. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure during maintenance activities was minimal, but due to mechanical difficulties dust monitoring could not be conducted during operation. Noise exposure was significant. Further testing for each of these exposures is recommended because of the outdoor environment where the testing demonstration took place. This may cause the results to be inaccurate. It is feasible that the dust and noise levels will be higher in an enclosed environment. In addition, other safety and health issues found were ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, and arm-hand vibration

  20. Elevated extracellular K+ inhibits apoptosis of corneal epithelial cells exposed to UV-B radiation.

    Science.gov (United States)

    Singleton, Katherine R; Will, David S; Schotanus, Mark P; Haarsma, Loren D; Koetje, Leah R; Bardolph, Susan L; Ubels, John L

    2009-08-01

    The goal of this study was to determine if the high [K(+)] in tears, 20-25 mM, serves to protect corneal epithelial cells from going into apoptosis after exposure to ambient UV-B radiation. Human corneal-limbal epithelial (HCLE) cells in culture were exposed to UV-B at doses of 50-200 mJ/cm(2) followed by measurement of K(+) channel activation and activity of apoptotic pathways. Patch-clamp recording showed activation of K(+) channels after UV-B exposure at 80 mJ/cm(2) or 150 mJ/cm(2) and a decrease in UV-induced K(+) efflux with increasing [K(+)](o). The UV-activated current was partially blocked by the specific K(+) channel blocker, BDS-1. DNA fragmentation, as measured by the TUNEL assay, was induced after exposure to UV-B at 100-200 mJ/cm(2). DNA fragmentation was significantly decreased when cells were incubated in 25, 50 or 100mM K(o)(+) after exposure to UV-B. The effector caspase, caspase-3, was activated by exposure to UV-B at 50-200 mJ/cm(2), but there was a significant decrease in activation when the cells were incubated in 25, 50 or 100mM K(o)(+) following exposure to UV-B. A decrease in mitochondrial potential, a possible activator of caspase-3, occurred after exposure to UV-B at 100-200 mJ/cm(2). This decrease in mitochondrial potential was prevented by 100mM K(o)(+); however, 25 or 50mM K(o)(+) provided minimal protection. Caspase-9, which is in the pathway from mitochondrial potential change to caspase-3 activation, showed little activation by UV-B radiation. Caspase-8, an initiator caspase that activates caspase-3, was activated by exposure to UV-B at 50-200 mJ/cm(2), and this UV-activation was significantly reduced by 25-100mM K(o)(+). The data show that the physiologically relevant [K(+)](o) of 25 mM can inhibit UV-B induced activation of apoptotic pathways. This suggests that the relatively high [K(+)] in tears reduces loss of K(+) from corneal epithelial cells in response to UV exposure, thereby contributing to the protection of the ocular

  1. Protective effect of 4-coumaric acid from UVB ray damage in the rabbit eye

    International Nuclear Information System (INIS)

    Lodovici, Maura; Caldini, Silvia; Morbidelli, Lucia; Akpan, Victor; Ziche, Marina; Dolara, Piero

    2009-01-01

    UV-induced oxidation damage seems to play a major role in a number of specific pathological conditions of intraocular tissues, such as cataract formation and retinal degeneration. Therefore, antioxidant and/or scavenger compounds might protect the eyes from UV-induced cellular damage. We previously reported that 4-coumaric acid (4-CA) is able to protect rabbit corneal-derived cells (SIRC) from UVB-induced oxidation damage. In this study we evaluated the protective effect of 4-CA against UVB-induced cell damage in rabbit cornea in vivo. Twelve male New Zealand albino rabbits were used; four rabbits were used as a control and received vehicle in one eye and 4-CA acid in the contralateral eye; eight rabbits were exposed to UVB rays (79.2 mJ/cm 2 ) and three days before to UV exposure each animal received 1 drop/day of vehicle in one eye and 1 drop/day of vehicle containing 4-CA (164 ng) in the contralateral eye. Corneal and sclera tissues were removed and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) levels were measured. Superoxide dismutase (SOD) and xanthine oxidase (XO) activities were determined in aqueous humour. UVB-induced vessel hyper-reactivity was strongly reduced at 4 and 24 h after UVB exposure after local treatment with 4-CA, 8-oxodGuo levels, a marker of oxidative DNA damage, were significantly increased (P < 0.05) in sclera and cornea by UVB irradiation, but when 4-CA was administered to the conjunctiva in a buffered solution once a day for 3 d before and 6 d after UVB exposure, levels of 8-oxodGuo were similar to controls and significantly reduced (P < 0.05) compared to UVB-treated corneas. XO activity in the aqueous humour was significantly increased. The administration of 4-CA for 3 d before and 6 d after UVB irradiation induced a small but significant (P < 0.05) reduction of XO compared with control eyes. Our results indicate that the administration of 4-CA protects eye tissues, thus reducing the harmful effect of UVB radiation at low

  2. New Vacuum Electronic Devices for Radar

    Directory of Open Access Journals (Sweden)

    Hu Yinfu

    2016-08-01

    Full Text Available Vacuum Electronic Devices (VEDs which are considered as the heart of a radar system, play an important role in their development. VEDs and radar systems supplement and promote each other. Some new trends in VEDs have been observed with advancements in the simulation tools for designing VEDs, new materials, new fabrication techniques. Recently, the performance of VEDs has greatly improved. In addition, new devices have been invented, which have laid the foundation for the developments of radar detection technology. This study introduces the recent development trends and research results of VEDs from microwave and millimeter wave devices and power modules, integrated VEDs, terahertz VEDs, and high power VEDs.

  3. Discovery Mondays: Much ado about nothing: vacuums

    CERN Multimedia

    2004-01-01

    Most people seem to agree that an empty space has nothing in it. But what about the physicists? "Wait a minute!", they will tell you, at the Microcosm's next Discovery Monday on 5th April, for they know that even interstellar space is not as empty as it might seem... Come and discover the technological advances made at CERN and their everyday applications. Take a step into the world of the vacuum... The event will take place in the Microcosm on 5th April, from 7.30 p.m. to 9.00 p.m. Entrance is free.

  4. Photomorphogenic effects of UV-B radiation on plants: consequences for light competition

    International Nuclear Information System (INIS)

    Barnes, P.W.; Ballaré, C.L.; Caldwell, M.M.

    1996-01-01

    A combination of field and labotatory studies were conducted to explore the nature of photomorphogenic effects of ultraviolet-B radiation (UV-B; 280–320 nm) on plant morphology and to evaluate the ecological consequences of these alterations in morphology for interspecific competition. Under laboratory conditions, seedlings of cucumber (Cucumis sativus L.) and tomato (Lycopersicon esculentum Mill.) exhibited appreciable (ca. 50%) and rapid (< 3h) inhibition in hypocotyl elongation in response to UV-B exposure. In cucumber, this inhibition was reversible, occurred without any associated changes in dry matter production and was caused by UV-B incident on the cotyledons and not the stem or growing tip. Inhibition of stem elongation in etiolated tomato seedlings occurred at least 3 h prior to the onset of accumulation of UV-absorbing pigments and monochromatic UV supplied against a background of visible radiation revealed maximum effectiveness in inhibition around 300 nm. Collectively, these findings suggest that a specific, but yet unidentified, UV-B photoreceptor is involved in mediating certain morphological responses to UV-B. For mixtures of wheat (Triticum aestivum L.) and wild oat (Avena fatua L.), a common weedy competitor, supplemental UV-B irradiation in the field differentially altered shoot morphology which resulted in changes in canopy structure, light interception and calculated stand photosynthesis. It is argued that, because of its asymmetrical nature, competition for light can potentially amplify the effects of UV-B on shoot morphology and may, therefore, be an important mechanism by which changes in the solar UV-B spectrum associated with stratospheric ozone reduction could alter the composition and character of terrestrial vegetation

  5. Silicon nanoparticles more effectively alleviated UV-B stress than silicon in wheat (Triticum aestivum) seedlings.

    Science.gov (United States)

    Tripathi, Durgesh Kumar; Singh, Swati; Singh, Vijay Pratap; Prasad, Sheo Mohan; Dubey, Nawal Kishore; Chauhan, Devendra Kumar

    2017-01-01

    The role of silicon (Si) in alleviating biotic as well as abiotic stresses is well known. However, the potential of silicon nanoparticle (SiNP) in regulating abiotic stress and associated mechanisms have not yet been explored. Therefore, in the present study hydroponic experiments were conducted to investigate whether Si or SiNp are more effective in the regulation of UV-B stress. UV-B (ambient and enhanced) radiation caused adverse effect on growth of wheat (Triticum aestivum) seedlings, which was accompanied by declined photosynthetic performance and altered vital leaf structures. Levels of superoxide radical and H 2 O 2 were enhanced by UV-B as also evident from their histochemical stainings, which was accompanied by increased lipid peroxidation (LPO) and electrolyte leakage. Activities of superoxide dismutase and ascorbate peroxidase were inhibited by UV-B while catalase and guaiacol peroxidase, and all non-enzymatic antioxidants were stimulated by UV-B. Although, nitric oxide (NO) content was increased at all tested combinations, but its maximum content was observed under SiNps together with UV-B enhanced treatment. Pre-additions of SiNp as well as Si protected wheat seedlings against UV-B by regulating oxidative stress through enhanced antioxidants. Data indicate that SiNp might have protected wheat seedlings through NO-mediated triggering of antioxidant defense system, which subsequently counterbalance reactive oxygen species-induced damage to photosynthesis. Further, SiNp appear to be more effective in reducing UV-B stress than Si, which is related to its greater availability to wheat seedlings. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  6. Analysis of differentially expressed genes under UV-B radiation in the desert plant Reaumuria soongorica.

    Science.gov (United States)

    Liu, Meiling; Li, Xinrong; Liu, Yubing; Shi, Yulan; Ma, Xiaofei

    2015-12-15

    Reaumuria soongorica is one of the typical desert plants that present excellent tolerance to adverse environments. However, its molecular response to UV-B radiation remains poorly understood. To test the response and tolerance mechanisms of R. soongorica to the increasing UV-B radiation, the differentially expressed genes (DEGs) were investigated between the control and UV-B radiation groups. A total of 2150 DEGs were detected between the two groups, of which 561 were up-regulated and 1589 were down-regulated. For functional analysis, DEGs were divided into three groups: (i) Chloroplast-localized proteins, including photosynthesis-associated proteins, ribulose-phosphate-3-epimerase, and ATP-dependent Clp protease. Their transcripts were inhibited, implying that the normal function of chloroplast was affected by UV-B radiation. (ii) Proteins involved in signaling transduction, such as phototropins and GTP-binding proteins. The transcriptional alternation of phototropins may reduce the penetration of UV-B radiation by regulating phototropism, stomatal opening, and chloroplast relocation. The down regulation of GTP-binding proteins may inhibit replication of potentially damaged DNA through preventing cell division; and (iii) proteins for lipid transfer and flavonoids biosynthesis. The up-regulation of these genes suggested that lipid transfer and flavonoids may have a protective function in response to UV-B radiation. Thus, UV-B radiation may lead to the disruption of chloroplasts function. The induction of genes for signal transduction and protective proteins may be a strategy for responding to UV-B radiation in R. soongorica. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Inhibition of UV-B induced apoptosis in corneal epithelial cells by potassium channel modulators.

    Science.gov (United States)

    Ubels, John L; Schotanus, Mark P; Bardolph, Susan L; Haarsma, Loren D; Koetje, Leah R; Louters, Julienne R

    2010-02-01

    The goal of this study was to determine whether prevention of K(+) loss can protect human corneal-limbal epithelial (HCLE) cells from UV-B induced apoptosis. Immunostaining for activated caspase-3 of HCLE cells exposed to 150-200 mJ/cm(2) UV-B demonstrated induction of apoptosis 6 h after exposure. The number of apoptotic cells was decreased by incubation in medium with 25 or 100 mM K(+). If this protection is due to a reduction of UV-induced K(+) loss then K(+) channel blockers should also protect HCLE cells from UV-B. Caspase-8 activity induced by exposure to UV-B at 150 mJ/cm(2) was significantly reduced when the cells were incubated in 0.3 microM BDS-I or 0.05-1 mM quinidine. Caspase-3 was also activated by UV-B and a reduction in activity was observed after incubation in 0.1-0.3 microM BDS-I and 0.1-1 mM quinidine. Induction of DNA fragmentation, as measured by the TUNEL assay, was decreased by treatment with 0.3 microM BDS-I and 0.01-0.05 mM quinidine. Patch-clamp recording showed activation of K(+) channels after exposure to UV-B and a decrease in outward K(+) current was observed following application of BDS-I. Quinidine did not block K(+) currents in HCLE cells, suggesting that the protective effect of quinidine occurs by a mechanism other than via K(+) channels. The effect of the K(+) channel blocker BDS-1 on HCLE cells exposed to UV-B confirms that preventing K(+) efflux protects corneal epithelial cells from apoptosis. This suggests the elevated [K(+)] in tears may protect the corneal epithelium from effects of ambient UV-B. Copyright 2009 Elsevier Ltd. All rights reserved.

  8. Sensitivity and Acclimation of Three Canopy-Forming Seaweeds to UVB Radiation and Warming

    KAUST Repository

    Xiao, Xi

    2015-12-02

    Canopy-forming seaweeds, as primary producers and foundation species, provide key ecological services. Their responses to multiple stressors associated with climate change could therefore have important knock-on effects on the functioning of coastal ecosystems. We examined interactive effects of UVB radiation and warming on juveniles of three habitat-forming subtidal seaweeds from Western Australia–Ecklonia radiata, Scytothalia dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16–30°C with or without UVB radiation and growth, health status, photosynthetic performance, and light absorbance measured. Furthermore, we used empirical models from the metabolic theory of ecology to evaluate the sensitivity of these important seaweeds to ocean warming. Results indicated that responses to UVB and warming were species specific, with Sargassum showing highest tolerance to a broad range of temperatures. Scytothalia was most sensitive to elevated temperature based on the reduced maximum quantum yields of PSII; however, Ecklonia was most sensitive, according to the comparison of activation energy calculated from Arrhenius’ model. UVB radiation caused reduction in the growth, physiological responses and thallus health in all three species. Our findings indicate that Scytothalia was capable of acclimating in response to UVB and increasing its light absorption efficiency in the UV bands, probably by up-regulating synthesis of photoprotective compounds. The other two species did not acclimate over the two weeks of exposure to UVB. Overall, UVB and warming would severely inhibit the growth and photosynthesis of these canopy-forming seaweeds and decrease their coverage. Differences in the sensitivity and acclimation of major seaweed species to temperature and UVB may alter the balance between species in future seaweed communities under climate change.

  9. Sensitivity and Acclimation of Three Canopy-Forming Seaweeds to UVB Radiation and Warming.

    Science.gov (United States)

    Xiao, Xi; de Bettignies, Thibaut; Olsen, Ylva S; Agusti, Susana; Duarte, Carlos M; Wernberg, Thomas

    2015-01-01

    Canopy-forming seaweeds, as primary producers and foundation species, provide key ecological services. Their responses to multiple stressors associated with climate change could therefore have important knock-on effects on the functioning of coastal ecosystems. We examined interactive effects of UVB radiation and warming on juveniles of three habitat-forming subtidal seaweeds from Western Australia-Ecklonia radiata, Scytothalia dorycarpa and Sargassum sp. Fronds were incubated for 14 days at 16-30°C with or without UVB radiation and growth, health status, photosynthetic performance, and light absorbance measured. Furthermore, we used empirical models from the metabolic theory of ecology to evaluate the sensitivity of these important seaweeds to ocean warming. Results indicated that responses to UVB and warming were species specific, with Sargassum showing highest tolerance to a broad range of temperatures. Scytothalia was most sensitive to elevated temperature based on the reduced maximum quantum yields of PSII; however, Ecklonia was most sensitive, according to the comparison of activation energy calculated from Arrhenius' model. UVB radiation caused reduction in the growth, physiological responses and thallus health in all three species. Our findings indicate that Scytothalia was capable of acclimating in response to UVB and increasing its light absorption efficiency in the UV bands, probably by up-regulating synthesis of photoprotective compounds. The other two species did not acclimate over the two weeks of exposure to UVB. Overall, UVB and warming would severely inhibit the growth and photosynthesis of these canopy-forming seaweeds and decrease their coverage. Differences in the sensitivity and acclimation of major seaweed species to temperature and UVB may alter the balance between species in future seaweed communities under climate change.

  10. In vivo UVB irradiation induces clustering of Fas (CD95) on human epidermal cells

    DEFF Research Database (Denmark)

    Bang, Bo; Gniadecki, Robert; Larsen, Jørgen K

    2003-01-01

    of soluble FasL in suction blister fluid from UVB-irradiated skin did not differ from those in unirradiated skin (n=5). Confocal laser scanning microscopy showed a rapid clustering of Fas within 30 min after irradiation. A simultaneous clustering of the adapter signalling protein FADD suggested that Fas...... clustering has a functional significance. Our results ar in accordance with previous findings from in vitro studies, and suggest that Fas is activated in vivo in human epidermis after UVB exposure....

  11. Inhibition of UV-B Induced Apoptosis in Corneal Epithelial Cells by Potassium Channel Modulators

    Science.gov (United States)

    Ubels, John L.; Schotanus, Mark P.; Bardolph, Susan L.; Haarsma, Loren D.; Koetje, Leah R.; Louters, Julienne R.

    2009-01-01

    The goal of this study was to determine whether prevention of K+ loss can protect human corneal-limbal epithelial (HCLE) cells from UV-B induced apoptosis. Immunostaining for activated caspase-3 of HCLE cells exposed to 150 – 200 mJ/cm2 UV-B demonstrated induction of apoptosis 6 hrs after exposure. The number of apoptotic cells was decreased by incubation in medium with 25 or 100 mM K+. If this protection is due to a reduction of UV induced K+ loss then K+ channel blockers should also protect HCLE cells from UV-B. Caspase-8 activity induced by exposure to UV-B at 150 mJ/cm2 was significantly reduced when the cells were incubated in 0.3 µM BDS-I or 0.05–1 mM quinidine. Caspase-3 was also activated by UV-B and a reduction in activity was observed after incubation in 0.1–0.3 µM BDS-I and 0.1–1mM quinidine. Induction of DNA fragmentation, as measured by the TUNEL assay, was decreased by treatment with 0.3 µM BDS-I and 0.01–0.05 mM quinidine. Patch-clamp recording showed activation of K+ channels after exposure to UV-B and a decrease in outward K+ current was observed following application of BDS-I. Quinidine did not block K+ currents in HCLE cells, suggesting that the protective effect of quinidine occurs by a mechanism other than via K+ channels. The effect of the K+ channel blocker BDS-1 on HCLE cells exposed to UV-B confirms that preventing K+ efflux protects corneal epithelial cells from apoptosis. This suggests the elevated [K+] in tears may protect the corneal epithelium from effects of ambient UV-B. PMID:19874821

  12. Vacuum in intensive gauge fields

    International Nuclear Information System (INIS)

    Matinian, S.G.

    1977-12-01

    The behaviour of vacuum in a covariantly constant Yang-Mills field is considered. The expressions for the effective Lagrangian in an intensive field representing the asymptotic freedom of the theory are found

  13. ITER diagnostic system: Vacuum interface

    International Nuclear Information System (INIS)

    Patel, K.M.; Udintsev, V.S.; Hughes, S.; Walker, C.I.; Andrew, P.; Barnsley, R.; Bertalot, L.; Drevon, J.M.; Encheva, A.; Kashchuk, Y.; Maquet, Ph.; Pearce, R.; Taylor, N.; Vayakis, G.; Walsh, M.J.

    2013-01-01

    Diagnostics play an essential role for the successful operation of the ITER tokamak. They provide the means to observe control and to measure plasma during the operation of ITER tokamak. The components of the diagnostic system in the ITER tokamak will be installed in the vacuum vessel, in the cryostat, in the upper, equatorial and divertor ports, in the divertor cassettes and racks, as well as in various buildings. Diagnostic components that are placed in a high radiation environment are expected to operate for the life of ITER. There are approx. 45 diagnostic systems located on ITER. Some diagnostics incorporate direct or independently pumped extensions to maintain their necessary vacuum conditions. They require a base pressure less than 10 −7 Pa, irrespective of plasma operation, and a leak rate of less than 10 −10 Pa m 3 s −1 . In all the cases it is essential to maintain the ITER closed fuel cycle. These directly coupled diagnostic systems are an integral part of the ITER vacuum containment and are therefore subject to the same design requirements for tritium and active gas confinement, for all normal and accidental conditions. All the diagnostics, whether or not pumped, incorporate penetration of the vacuum boundary (i.e. window assembly, vacuum feedthrough etc.) and demountable joints. Monitored guard volumes are provided for all elements of the vacuum boundary that are judged to be vulnerable by virtue of their construction, material, load specification etc. Standard arrangements are made for their construction and for the monitoring, evacuating and leak testing of these volumes. Diagnostic systems are incorporated at more than 20 ports on ITER. This paper will describe typical and particular arrangements of pumped diagnostic and monitored guard volume. The status of the diagnostic vacuum systems, which are at the start of their detailed design, will be outlined and the specific features of the vacuum systems in ports and extensions will be described

  14. Ultraviolet B (UVB) induced DNA damage affects alternative splicing in skin cells

    International Nuclear Information System (INIS)

    Munoz, M.J.; Nieto Moreno, N.; Kornblihtt, A.R.

    2010-01-01

    The ultraviolet (UV) radiation from the Sun that reaches the Earth's surface is a combination of low (UVA, 320-400 nm) and high (UVB, 290-320 nm) energy light. UVB light causes two types of mutagenic DNA lesions: thymine dimers and (6-4) photo-products. UVB mutagenesis is a critical step in the generation of different forms of skin cancer, which develops almost exclusively in sun exposed areas. We have previously shown that RNA polymerase II (pol II) hyperphosphorylation induced by UVC (254 nm) irradiation of non-skin cells inhibits pol II elongation rates which in turn affects alternative splicing (AS) patterns, altering the synthesis of pro- and anti-apoptotic isoforms of key proteins like Bcl-x or Caspase 9 (C9). Since the UVC radiation is fully filtered by the ozone layer and AS regulation in skin pathologies has been poorly studied, we decided to extend our studies to human keratinocytes in culture treated with UVB (302 nm) light. We observed that pol II hyperphosphorylation is increased upon UVB irradiation, being this modification necessary for the observed change in AS of a model cassette exon. Moreover, UVB irradiation induces the proapoptotic mRNA isoforms of Bcl-x and C9 consistently with a key role of AS in skin response to DNA damage. (authors)

  15. Joint additive effects of temperature and UVB radiation on zoeae of the crab Taliepus dentatus

    KAUST Repository

    Carreja, B

    2016-04-06

    Warming and enhanced ultraviolet B (UVB) radiation are 2 global stressors acting across the ocean. We tested their effects on the survival and performance (consumption rates and activity) on the zoea I stage of the Chilean kelp crab Taliepus dentatus. Our goal was to resolve whether these stressors, when acting concurrently, had additive or interactive effects, either synergistic or antagonistic. A multifactorial experiment of 4 temperatures and 3 UVB irradiance levels was run. The larvae showed a significant increase in mortality with increasing temperature. Exposure to UVB reduced the thermal tolerance of the larvae by a significant increase of their mortality rate. Oxygen consumption increased as temperature increased. When exposed to UVB radiation, larval oxygen consumption increased significantly for all the temperatures tested. Two statistical models of joint effects confirmed that the combined effect of both stressors was additive, with no interaction, either synergistic or antagonistic. One of them, the independent action (IA) model, also revealed that concurrent effects on mortality remained additive when doubling the UVB dose. Additivity of the stressors improved the predictability of their effects on larval mortality. Exposure to UVB radiation increased mortality rates by 1.5 times at any temperature tested, independently of the dose. © The authors 2016.

  16. Protective effect of mango (Mangifera indica L.) against UVB-induced skin aging in hairless mice.

    Science.gov (United States)

    Song, Jae Hyoung; Bae, Eun Young; Choi, Goya; Hyun, Jin Won; Lee, Mi Young; Lee, Hye Won; Chae, Sungwook

    2013-04-01

    Mangifera indica L. (Anacardiaceae) is a medicinal plant whose extracts have been described as an antioxidant with anti-inflammatory and immunomodulatory activities. Skin aging is a consequence of chronic sun exposure to the sun and therefore ultraviolet (UV) radiation. Naturally occurring antioxidants are known to reduce skin aging. Therefore, the aim of the present study was to evaluate the protective role of mango extract against UVB-induced skin aging in hairless mice. HR-1 hairless male mice (6 weeks old) were divided into three groups: control (n = 5), UVB-treated vehicle (n = 5), and UVB-treated mango extract (n = 5) groups. UVB-irradiated mice from the mango extract group were orally administered 0.1 ml of water containing 100 mg of mango extract/kg body weight per day. The inhibitory activity of mango extract on wrinkle formation was determined by the analysis of the skin replica, epidermal thickness based on histological examination, and damage to collagen fiber. The mean length of wrinkles in UVB-treated vehicle group significantly improved after the oral administration of mango extract, which significantly inhibited the increase in epidermal thickness and epidermal hypertrophy (P mango extract by Masson's trichrome staining. These results indicate that mango extract showed anti-photoaging activity in UVB-irradiated hairless mice. © 2013 John Wiley & Sons A/S.

  17. UVB-induced mutagenesis in hairless λlacZ-transgenic mice

    International Nuclear Information System (INIS)

    Frijhoff, A.F.W.; Rebel, H.; Mientjes, E.J.

    1997-01-01

    UVB-induced mutagenesis was studied in hairless 40.6 transgenic mice (Muta trademark Mouse), which contain the λgt1OlacZ shuttle vector as a target for mutagenesis. Mice were exposed at the dorsal side to either single doses of 200, 500, 800, or 1000 J/m 2 UVB or to two successive irradiations of either 200 and 800 J/m 2 UVB, with intervals of 1,3, or 5 days, or to 800 and 200 J/m 2 UVB with a 5-day interval. At 23 days after the last exposure, lacZ mutant frequencies (MF) were determined in the epidermis. The lacZ MF increased linearly with increasing dose of UVB. The mutagenic effect of two successive irradiations appeared to be additive. The UV-induced mutation spectrum was dominated by G:C→A:T transitions at dipyrimidine sites. DNA-sequence analysis of spontaneously mutated phages showed a diverse spectrum consisting of insertions, deletions and G:C → A:T transitions at CpG sites. the results indicate that the hairless λlacZ-transgenic mouse is a suitable in vivo model for studying UVB-induced mutations. 29 refs., 5 tabs

  18. UV-B photoreceptor-mediated protection of the photosynthetic machinery in Chlamydomonas reinhardtii

    Science.gov (United States)

    Allorent, Guillaume; Lefebvre-Legendre, Linnka; Chappuis, Richard; Kuntz, Marcel; Truong, Thuy B.; Niyogi, Krishna K.; Goldschmidt-Clermont, Michel

    2016-01-01

    Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green alga Chlamydomonas reinhardtii that UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast. PMID:27930292

  19. Ultraviolet B (UVB) induced DNA damage affects alternative splicing in skin cells

    International Nuclear Information System (INIS)

    Nieto Moreno, N.; Dujardin, G.; Kornblihtt, A.R.; Muñoz, M.J.

    2011-01-01

    The ultraviolet (UV) radiation from the Sun that reaches the Earth’s surface is a combination of low (UVA, 320-400nm) and high (UVB, 290-320nm) energy light. UVB light causes two types of mutagenic DNA lesions: thymine dimers and (6-4)photo-products. UVB mutagenesis is critical in the generation of skin cancer. We have previously shown that RNA polymerase II (pol II) hyperphosphorylation induced by UVC (254 nm) irradiation of non-skin cells inhibits pol II elongation rates which in turn affects alternative splicing (AS) patterns favouring the synthesis of proapoptotic isoforms of key proteins like Bcl-x or Caspase 9 (C9). As UVC radiation is fully filtered by the ozone layer and AS regulation in skin pathologies has been poorly studied, we decided to extend our studies to human keratinocytes in culture treated with UVB (302nm) light. We observed an increase in pol II hyperphosphorylation, being this modification necessary for the change in AS of a model cassette exon. Moreover, UVB irradiation induces the pro-apoptotic mRNA isoforms of Bcl-x and C9 being these consistent with a key role of AS in response to DNA damage. Our results suggest that UVC and UVB light affect AS decisions through a similar mechanism. This indicates that lower energy irradiation, causing more limited DNA damage than UVC light, is sufficient to alter qualitatively patterns of gene expression in skin cells. (authors)

  20. Influence of water and salt solutions on UVB irradiation of normal skin and psoriasis

    International Nuclear Information System (INIS)

    Boer, J.; Schothorst, A.A.; Boom, B.; Suurmond, D.; Hermans, J.

    1982-01-01

    The influence of tap-water (TW) and salt solutions on the minimal erythema dose (MED) was investigated for normal human skin and uninvolved skin of psoriasis patients. MED (UVB) determinations on the forearm revealed that: (1) the MED definitely decreases whenever the arm is immersed in TW or NaCl solutions with a low concentration (4%) prior to UVB exposure, whereas almost saturated NaCl solution (26%), as well as locum Dead Sea water (LDSW), do not produce a change in the MED, and (2) the decrease in MED obtained by wetting the skin with TW was no longer present when the skin was allowed to dry for 20 min. A decrease in water uptake by skin (in vivo) and by callus (in vitro) was found as the salt concentration of the external solution increased. It is proposed that water taken up by the skin plays an important role in the sensitivity of the skin to UVB exposure. Bathing in TW or 4% NaCl prior to UVB exposure offered a slight to moderate improvement in psoriasis over UVB irradiation alone. Finally, it was shown that there is no obvious difference in clearance of the psoriatic skin between a bath in TW, 4% NaCl, or LDSW prior to UVB exposure. (orig.)

  1. Saponins from Tribulus terrestris L. protect human keratinocytes from UVB-induced damage.

    Science.gov (United States)

    Sisto, Margherita; Lisi, Sabrina; D'Amore, Massimo; De Lucro, Raffaella; Carati, Davide; Castellana, Donatello; La Pesa, Velia; Zuccarello, Vincenzo; Lofrumento, Dario D

    2012-12-05

    Chronic exposure to solar UVB radiation damages skin, increasing the risk to develop cancer. Hence the identification of compounds with a photoprotective efficacy is essential. This study examined the role of saponins derived from Tribulus terrestris L. (TT) on the modulation of apoptosis in normal human keratinocytes (NHEK) exposed to physiological doses of UVB and to evaluate their antitumoral properties. In NHEK, TT saponins attenuate UVB-induced programmed cell death through inhibition of intrinsic apoptotic pathway. In squamous cell carcinomas (SCC) TT saponins do not make the malignant keratinocytes more resistant to UVB and determine an enhanced apoptotic response. The photoprotective effect of TT saponins is tightly correlated to the enhancement of NER genes expression and the block of UVB-mediated NF-κB activation. Collectively, our study shows experimental evidence that TT has a preventive efficacy against UVB-induced carcinogenesis and the molecular knowledge on the mechanisms through which TT saponins regulate cell death suggests great potential for TT to be developed into a new medicine for cancer patients. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Study of hemoglobin response to mid-ultraviolet (UVB) radiation using micro-Raman spectroscopy

    Science.gov (United States)

    Huang, Y. Y.; Li, N.; Zhou, S. N.; Huang, Z. T.; Zhuang, Z. F.

    2017-09-01

    Confocal micro-Raman spectroscopy is employed to monitor the damage to haemoglobin from mid-ultraviolet (UVB) radiation. We obtained the Raman spectra of an erythrocyte, which indicated that a peroxidation reaction occurs after UVB radiation. Further, the surface enhanced Raman scattering (SERS) spectra of isolated haemoglobin show that the intensities of the 1375 and 1399 cm-1 bands, which are markers of haem aggregation, obviously increase with prolonged UVB irradiation. This increase reveals that haem aggregation occurs in the peroxidation of erythrocytes. The UV-Vis spectra of isolated haemoglobin indicate that the Soret band, which is indicative of excitonic interactions in the aggregated haems, has a redshift ( 12 nm) after 30 min of UVB irradiation of erythrocytes. It can be deduced that an excitonic interaction occurs in the aggregated haems, which is caused by haemoglobin denaturation following UVB irradiation. In addition, the changes of the Raman marker bands during aggregation primarily originate from excitonic interactions. Throughout the process, a higher UVB radiation dose causes greater damage to haemoglobin.

  3. Technical specification for vacuum systems

    International Nuclear Information System (INIS)

    Khaw, J.

    1987-01-01

    The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10 -5 to 10 -11 Torr. The primary gas loads during operation result from thermal desorption and beam-induced desorption from the vacuum chamber walls. These desorption rates can be extremely high in the case of hydrocarbons and other contaminants. These specifications place a major emphasis on eliminating contamination sources. The specifications and procedures have been written to insure the cleanliness and vacuum integrity of all SLAC vacuum systems, and to assist personnel involved with SLAC vacuum systems in choosing and designing components that are compatible with existing systems and meet the quality and reliability of SLAC vacuum standards. The specification includes requirements on design, procurement, fabrication, chemical cleaning, clean room practices, welding and brazing, helium leak testing, residual gas analyzer testing, bakeout, venting, and pumpdown. Also appended are specifications regarding acceptable vendors, isopropyl alcohol, bakeable valve cleaning procedure, mechanical engineering safety inspection, notes on synchrotron radiation, and specifications of numerous individual components

  4. Vacuum-assisted cesarean section

    Directory of Open Access Journals (Sweden)

    McQuivey RW

    2017-03-01

    Full Text Available Ross W McQuivey,1 Jon E Block2 1Clinical Innovations, Salt Lake City, UT, 2Independent consultant, San Francisco, CA, USA Abstract: There has been a dramatic rise in the frequency of cesarean sections, surpassing 30% of all deliveries in the US. This upsurge, coupled with a decreasing willingness to allow vaginal birth after cesarean section, has resulted in an expansion of the use of vacuum assistance to safely extract the fetal head. By avoiding the use of a delivering hand or forceps blade, the volume being delivered through the uterine incision can be decreased when the vacuum is used properly. Reducing uterine extensions with their associated complications (eg, excessive blood loss in difficult cases is also a theoretical advantage of vacuum delivery. Maternal discomfort related to excessive fundal pressure may also be lessened. To minimize the risk of neonatal morbidity, proper cup placement over the “flexion point” remains essential to maintain vacuum integrity and reduce the chance of inadvertent detachment and uterine extensions. Based on the published literature and pragmatic clinical experience, utilization of the vacuum device is a safe and effective technique to assist delivery during cesarean section. Keywords: cesarean section, vacuum, forceps, birth, delivery

  5. Technical specification for vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Khaw, J. (ed.)

    1987-01-01

    The vacuum systems at the Stanford Linear Accelerator Center (SLAC) are primarily of all-metal construction and operate at pressures from 10/sup -5/ to 10/sup -11/ Torr. The primary gas loads during operation result from thermal desorption and beam-induced desorption from the vacuum chamber walls. These desorption rates can be extremely high in the case of hydrocarbons and other contaminants. These specifications place a major emphasis on eliminating contamination sources. The specifications and procedures have been written to insure the cleanliness and vacuum integrity of all SLAC vacuum systems, and to assist personnel involved with SLAC vacuum systems in choosing and designing components that are compatible with existing systems and meet the quality and reliability of SLAC vacuum standards. The specification includes requirements on design, procurement, fabrication, chemical cleaning, clean room practices, welding and brazing, helium leak testing, residual gas analyzer testing, bakeout, venting, and pumpdown. Also appended are specifications regarding acceptable vendors, isopropyl alcohol, bakeable valve cleaning procedure, mechanical engineering safety inspection, notes on synchrotron radiation, and specifications of numerous individual components. (LEW)

  6. Solar UV-B effects on PSII performance in Betula nana are influenced by PAR level and reduced by EDU

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, Helge

    2012-01-01

    The long-term and diurnal responses of photosystem II (PSII) performance to near-ambient UV-B radiation were investigated in High Arctic Betula nana. We conducted an UV exclusion experiment with five replicated blocks consisting of open control (no filter), photosynthetic active radiation and UV...... the effects of UV-B. Chlorophyll-a fluorescence induction curves were used for analysis of OJIP test parameters. Near-ambient UV-B radiation reduced across season maximum quantum yield (TRo /ABS = Fv /Fm ), approximated number of active PSII reaction center (RC/ABS) and the performance index (PIABS ), despite...... improved leaf screening against UV-B with higher content of UV-B-absorbing compounds and a lower specific leaf area. EDU application counteracted the negative impact of UV-B on TR(o) /ABS, RC/ABS and PI(ABS) . This indicates that the mechanisms behind UV-B and ozone damage share some common features...

  7. Effects of UV-B radiation on Olea europaea: comparisons between a greenhouse and a field experiment

    Energy Technology Data Exchange (ETDEWEB)

    Liakoura, V.; Stavrianakou, S.; Liakopoulos, G.; Karabourniotis, G. [Athens Agricultural Univ. Dept. of Agricultural Biotechnology, Athens (Greece); Manetas, Y. [Patras Univ, Dept, of Biology, Patras (Greece)

    1999-11-01

    Olea europaea plants were grown in the field with or without supplemental ultraviolet B radiation equivalent to the increase at ground level resulting from a 15 per cent depletion in stratospheric ozone concentration. After one year, their morphology, anatomy and physiology were compared with that of plants grown in a greenhouse and exposed for four months to either zero UV-B radiation or UV-B radiation equivalent to that of supplemented outdoor treatment. Results showed an increase in adaxial epidermal thickness and reduced total protein concentration in plants grown in the field, in contrast to greenhouse-grown plants which under the influence of UV-B radiation showed significant increases in abaxial cutical thickness and trichome UV-B absorbing compounds. These observations suggest that Olea europaea plants have a high UV-B tolerance and are not affected by increase in UV-B radiation. 23 refs., 1 tab.

  8. Role of UV-absorbing compounds in genetic differences in the resistance to UV-B radiation in rice plants

    International Nuclear Information System (INIS)

    Sato, T.; Kumagai, T.

    1997-01-01

    Parental cultivars (Oryza sativa L. Japanese lowland cultivars Sasanishiki and Norin 1), F 2 plants, and F 3 Iines were grown under visible light with or without supplemental UV-B radiation in a phytotron, to determine whether the accumulation of UV-absorbing compounds plays a role in the difference in UV-B resistance between these rice cultivars. The level of UV-absorbance per unit leaf area increased with the UV-B treatuent in all the leaves of these two rice cultivars, but was higher in Sasanishiki than in Norin 1 irrespective of UV-B treatment. An analysis by thin-layer chromatography and the UV-absorption spectra of the extracts did not show any qualitative difference in UV-absorbing compounds in leaf tissues between these two cultivars. There was a significant positive correlation between the level of UV-absorbance per unit leaf area and the fresh weight of aerial parts in the F 2 plants exposed to UV-B radiation. Furthermore, the level of UV-absorbance per unit leaf area tended to be higher in the F 3 Iines resistant to UV-B radiation than in those sensitive to such radiation regardless of whether these F 3 lines were exposed to supplemental UV-B radiation. These results suggest that the differences in UV-B resistance between Sasanishiki and Norin 1 are associated with genetic differences in the level of accumulation of UV-B absorbing compounds in leaf tissues. Based on these results we suggest that the accumulation of UV-B absorbing compounds is an important factor contributing to UV-B resistance in rice cultivars. Since the accumulation of UV-absorbing compounds in leaves appears to minimize the latent negative impact of UV-B radiation on rice production, it may be a useful character to select in ordinary breeding. (author)

  9. Preliminary results of sugar maple carbohydrate and growth response under vacuum and gravity sap extraction

    Science.gov (United States)

    Mark L. Isselhardt; Timothy D. Perkins; Abby K. van den Berg; Paul G. Schaberg

    2016-01-01

    Recent technological advancements have increased the amount of sugar-enriched sap that can be extracted from sugar maple (Acer saccharum). This pilot study quantified overall sugar removal and the impacts of vacuum (60 cm Hg) and gravity sap extraction on residual nonstructural carbohydrate (NSC) concentrations and on stem and twig growth. Vacuum...

  10. Effects of environmental and artificial UV-B radiation on freshwater prawn Macrobrachium olfersi embryos

    Energy Technology Data Exchange (ETDEWEB)

    Nazari, Evelise Maria [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil); Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Ammar, Dib [Universidade do Oeste de Santa Catarina, Departamento de Biologia, Campus Universitario, 89600-000 Joacaba, SC (Brazil); Bem, Andreza Fabro de; Latini, Alexandra [Universidade Federal de Santa Catarina, Departamento de Bioquimica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Mueller, Yara Maria Rauh [Universidade Federal de Santa Catarina, Departamento de Biologia Celular, Embriologia e Genetica, Campus Universitario, 88040-900 Florianopolis, SC (Brazil); Allodi, Silvana, E-mail: sallodi@histo.ufrj.br [Programa de Pos-Graduacao em Ciencias Morfologicas, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, 21949-902 Rio de Janeiro, RJ (Brazil)

    2010-06-01

    The recent decrease of the stratospheric ozone has resulted in an increase of ultraviolet-B (UV-B) radiation reaching the Earth's surface. In freshwater ecosystems with transparent water, UV-B rays easily penetrate and potentially cause harmful effects to organisms. In this study, embryos of the prawn Macrobrachium olfersi were used to evaluate the impact of UV-B rays in freshwater environments. We observed three groups of embryos: the first was to assess whether UV-B radiation produced morphological defects and/or biochemical impairments in the laboratory. The second was to check whether embryos with the same impairments as those observed in the laboratory were found in their environment, under natural solar radiation. The third group was the non-irradiated control. The embryos irradiated with 310 mW cm{sup -2} UV-B for 30 min showed morphological alterations similar to those observed in embryos from the environmental control group. The most important effects of the UV-B radiation observed in M. olfersi embryos were morphological (1.2% of the total number of embryos from the environment and 2.8% of the total number of irradiated embryos), pigmentation changes in the eyes (78.0% of the total number of embryos from the environment and 98.9% of the total number of irradiated embryos), and disruption of the chromatophores (46.9% of the total number of embryos from the environment and 95.5% of the total number of irradiated embryos). We also observed an increase in egg volume, which was accompanied by a significant increase in water content in UV-B irradiated groups when compared with aquaria control embryos. In addition, a significant decrease in the mitotic index in eggs exposed to UV-B radiation was detected (0.17 for the embryos from the aquaria control, 0.10 for the embryos of the environmental control, and 0.04 for the irradiated groups). The low levels of NPSH and high levels of TBARS indicated that UV-B rays directly compromised the antioxidant function of

  11. Distinct physiological and metabolic reprogramming by highbush blueberry (Vaccinium corymbosum) cultivars revealed during long-term UV-B radiation.

    Science.gov (United States)

    Luengo Escobar, Ana; Alberdi, Miren; Acevedo, Patricio; Machado, Mariana; Nunes-Nesi, Adriano; Inostroza-Blancheteau, Claudio; Reyes-Díaz, Marjorie

    2017-05-01

    Despite the Montreal protocol and the eventual recovery of the ozone layer over Antarctica, there are still concerns about increased levels of ultraviolet-B (UV-B) radiation in the Southern Hemisphere. UV-B induces physiological, biochemical and morphological stress responses in plants, which are species-specific and different even for closely related cultivars. In woody plant species, understanding of long-term mechanisms to cope with UV-B-induced stress is limited. Therefore, a greenhouse UV-B daily course simulation was performed for 21 days with two blueberry cultivars (Legacy and Bluegold) under UV-B BE irradiance doses of 0, 0.07 and 0.19 W m -2 . Morphological changes, photosynthetic performance, antioxidants, lipid peroxidation and metabolic features were evaluated. We found that both cultivars behaved differently under UV-B exposure, with Legacy being a UV-B-resistant cultivar. Interestingly, Legacy used a combined strategy: initially, in the first week of exposure its photoprotective compounds increased, coping with the intake of UV-B radiation (avoidance strategy), and then, increasing its antioxidant capacity. These strategies proved to be UV-B radiation dose dependent. The avoidance strategy is triggered early under high UV-B radiation in Legacy. Moreover, the rapid metabolic reprogramming capacity of this cultivar, in contrast to Bluegold, seems to be the most relevant contribution to its UV-B stress-coping strategy. © 2016 Scandinavian Plant Physiology Society.

  12. The changes in quality ingredients of Qi chrysanthemum flowers treated with elevated UV-B radiation at different growth stages.

    Science.gov (United States)

    Yao, Xiaoqin; Chu, Jianzhou; He, Xueli; Ma, Chunhui; Han, Chao; Shen, Haiyu

    2015-05-01

    The paper mainly reported the changes in quality ingredients of Qi chrysanthemum flowers treated with elevated UV-B radiation at different growth stages. The experiment included two levels of UV-B radiation (ambient UV-B, a 10% increase in ambient UV-B). Elevated UV-B radiation was carried out for 10-days during seedling, vigorous growth, bud and flower stages of Qi chrysanthemum, respectively. Elevated UV-B treatments applied during four development stages did not significantly affect flower yield, the rate of superoxide radical production and malondialdehyde concentration in flowers, while increased free amino acid concentration. The amino acid concentration induced by elevated UV-B radiation applied during bud stage was higher than that during the other stages. Elevated UV-B radiation applied during vigorous growth (except for flavone), bud and flower stages of chrysanthemum significantly increased hydrogen peroxide concentration, phenylalanine ammonia lyase enzyme activity, vitamin C, chlorogenic acid and flavone concentrations in flowers. These results suggested that active and nutritional ingredients in flowers of chrysanthemum could be increased by elevated UV-B radiation applied during the later growth stages of chrysanthemum. The paper supplied a simple and environmental-friendly method to improve quality of medicinal plants. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Characterization of the adaptive response of grapevine (cv. Tempranillo) to UV-B radiation under water deficit conditions.

    Science.gov (United States)

    Martínez-Lüscher, J; Morales, F; Delrot, S; Sánchez-Díaz, M; Gomès, E; Aguirreolea, J; Pascual, I

    2015-03-01

    This work aims to characterize the physiological response of grapevine (Vitis vinifera L.) cv. Tempranillo to UV-B radiation under water deficit conditions. Grapevine fruit-bearing cuttings were exposed to three levels of supplemental biologically effective UV-B radiation (0, 5.98 and 9.66kJm(-2)day(-1)) and two water regimes (well watered and water deficit), in a factorial design, from fruit-set to maturity under glasshouse-controlled conditions. UV-B induced a transient decrease in net photosynthesis (Anet), actual and maximum potential efficiency of photosystem II, particularly on well watered plants. Methanol extractable UV-B absorbing compounds (MEUVAC) concentration and superoxide dismutase activity increased with UV-B. Water deficit effected decrease in Anet and stomatal conductance, and did not change non-photochemical quenching and the de-epoxidation state of xanthophylls, dark respiration and photorespiration being alternative ways to dissipate the excess of energy. Little interactive effects between UV-B and drought were detected on photosynthesis performance, where the impact of UV-B was overshadowed by the effects of water deficit. Grape berry ripening was strongly delayed when UV-B and water deficit were applied in combination. In summary, deficit irrigation did not modify the adaptive response of grapevine to UV-B, through the accumulation of MEUVAC. However, combined treatments caused additive effects on berry ripening. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Seasonal Changes in Vitamin D-Effective UVB Availability in Europe and Associations with Population Serum 25-Hydroxyvitamin D

    Directory of Open Access Journals (Sweden)

    Colette M. O’Neill

    2016-08-01

    Full Text Available Low vitamin D status is common in Europe. The major source of vitamin D in humans is ultraviolet B (UVB-induced dermal synthesis of cholecalciferol, whereas food sources are believed to play a lesser role. Our objectives were to assess UVB availability (Jm−2 across several European locations ranging from 35° N to 69° N, and compare these UVB data with representative population serum 25-hydroxyvitamin D (25(OHD data from Ireland (51–54° N, Iceland (64° N and Norway (69° N, as exemplars. Vitamin D-effective UVB availability was modelled for nine European countries/regions using a validated UV irradiance model. Standardized serum 25(OHD data was accessed from the EC-funded ODIN project. The results showed that UVB availability decreased with increasing latitude (from 35° N to 69° N, while all locations exhibited significant seasonal variation in UVB. The UVB data suggested that the duration of vitamin D winters ranged from none (at 35° N to eight months (at 69° N. The large seasonal fluctuations in serum 25(OHD in Irish adults was much dampened in Norwegian and Icelandic adults, despite considerably lower UVB availability at these northern latitudes but with much higher vitamin D intakes. In conclusion, increasing the vitamin D intake can ameliorate the impact of low UVB availability on serum 25(OHD status in Europe.

  15. Combined impact of solar UV-B radiation and selenium treatment on respiratory potential in pumpkins (Cucurbita pepo L.)

    International Nuclear Information System (INIS)

    Germ, M.

    2005-01-01

    The effects of ambient and filtered solar UV-B radiation and of selenium treatment on respiratory potential measured by electron transport system (ETS) activity in pumpkins, Cucurbita pepo L. were studied. Measurements were conducted three times in the growth period. Solar UV-B radiation decreased ETS activity in plants, regardless selenium treatment. The results suggested that the solar UV-B radiation impaired flow of electrons in the respiratory chain. Selenium decreased ETS activity in plants exposed to solar UV-B radiation in the end of the vegetation period

  16. The effect of epidermal levels of urocanic acid on 25-hydroxyvitamin D synthesis and inflammatory mediators upon narrowband UVB irradiation

    DEFF Research Database (Denmark)

    Landeck, Lilla; Jakasa, Ivone; Dapic, Irena

    2016-01-01

    BACKGROUND/PURPOSE: Urocanic acid (UCA) absorbs ultraviolet (UV)B radiation in the epidermis which may interfere with phototherapy. Therefore, the influence of individual levels of UCA on immune reactivity and vitamin D synthesis induced by narrowband UVB radiation was assessed. METHODS: Twenty......: Narrowband UVB irradiation led to the conversion of trans-UCA into its cis-isomer in the epidermis. The observed increase in 25-hydroxyvitamin D serum concentrations was inversely correlated with the baseline levels of trans-UCA. Furthermore, UVB irradiation induced significant changes in the levels of CXCL...

  17. Effects of ultraviolet-B radiation (UV-B) on growth and physiology of the dune grassland species Calamagrostis epigeios

    International Nuclear Information System (INIS)

    Tosserams, M.; Rozema, J.

    1995-01-01

    Seedlings of Calamagrostis epigeios were exposed to four levels of UV-B radiation (280-320 nm), simulating up to 44% reduction of stratospheric ozone concentration during summertime in The Netherlands, to determine the response of this plant species to UV-B irradiation. After six weeks of UV-B treatment, total biomass of all UV-B treated plants was higher, compared to plants that had received no UV-B radiation. The increase of biomass did not appear to be the result of a stimulation of net photosynthesis. Also, transpiration rate and water use efficiency were not altered by UV-B at any exposure level. Pigment analysis of leaf extracts showed no effect of enhanced UV-B radiation on chlorophyll content and accumulation of UV absorbing pigments. UV-B irradiance, however, did reduce the transmittance of visible light (400-700 nm) of intact attached leaves, suggesting a change in anatomical characteristics of the leaves. Additionally, the importance of including an ambient UV-B treatment in indoor experiments is discussed

  18. Surface plasma waves over bismuth–vacuum interface

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 61; Issue 3. Surface plasma waves over bismuth–vacuum interface. Ashim P Jain J Parashar. Brief Report Volume 61 Issue ... Author Affiliations. Ashim P Jain1 J Parashar1. Department of Applied Physics, Samrat Ashok Technological Institute, Vidisha 464 001, India ...

  19. Development of vacuum glazing with advanced thermal properties - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Manz, H.

    2009-03-15

    Windows constitute a weak link in the building envelope and hence contribute significantly to the total heating energy demand in buildings. By evacuating the glazing cavity a vacuum glazing is created and heat transfer can be significantly reduced. This project was designed to build knowledge and technology necessary to fabricate vacuum glazing with advanced thermal properties. More specifically, various strategies for improvement of conventional technology were investigated. Of central importance was the development of a novel edge sealing approach which can in theory circumvent the main limitation of conventional glass soldering technology. This approach which is rapid, low temperature, low cost and completely vacuum compatible was filed for patenting in 2008. With regards to thermal insulation performance and glazing deflection, numerical studies were performed demonstrating the importance of nonlinear behavior with glazing size and the results published. A detailed service life prediction model was elaborated which defines a set of parameters necessary to keep the expected pressure increase below a threshold value of 0.1 Pa after 30 years. The model takes into account four possible sources of pressure increase and a getter material which acts as a sink. For the production of 0.5 m by 0.5 m glazing assembly prototypes, a high vacuum chamber was constructed and a first sealing prototype realized therein. The manufacture of improved prototypes and optimization of the anodic bonding edge sealing technology with emphasis on process relevant aspects is the goal of a follow-up project. (authors)

  20. Terra Vac In Situ Vacuum Extraction System: Applications Analysis Report

    Science.gov (United States)

    This document is an evaluation of the Terra Vac in situ vacuum extraction system and its applicability as a treatment method for waste site cleanup. This report analyzes the results from the Superfund Innovative Technology Evaluation (SITE) Program’s 56-day demonstration at t...

  1. DEMONSTRATION BULLETIN: IN-SITU VACUUM EXRACTION: TERRA VAC, INC.

    Science.gov (United States)

    This in-situ vacuum extraction technology is a process for the removal and venting of volatile organic compounds (VOCs) from the vadose or unsaturated zone of soils. Often, these compounds can be removed from the vadose zone before they have a chance to contaminate groundwater. ...

  2. Effects of solar UV-B radiation on aquatic ecosystems

    Science.gov (United States)

    Häder, D.-P.

    Solar UV degrades dissolved organic carbon photolytically so that they can readily be taken up by bacterioplankton. On the other hand solar UV radiation inhibits bacterioplankton activity. Bacterioplankton productivity is far greater than previously thought and is comparable to phytoplankton primary productivity. According to the "microbial loop hypothesis," bacterioplankton is seen in the center of a food web, having a similar function to phytoplankton and protists. The penetration of UV and PAR into the water column can be measured. Marine waters show large temporal and regional differences in their concentrations of dissolved and particulate absorbing substances. A network of dosimeters (ELDONET) has been installed in Europe ranging from Abisko in Northern Sweden to Gran Canaria. Cyanobacteria are capable of fixing atmospheric nitrogen which is then made available to higher plants. The agricultural potential of cyanobacteria has been recognized as a biological fertilizer for wet soils such as in rice paddies. UV-B is known to impair processes such as growth, survival, pigmentation, motility, as well as the enzymes of nitrogen metabolism and CO 2 fixation. The marine phytoplankton represents the single most important ecosystem on our planet and produces about the same biomass as all terrestrial ecosystems taken together. It is the base of the aquatic food chain and any changes in the size and composition of phytoplankton communities will directly affect food production for humans from marine sources. Another important role of marine phytoplankton is to serve as a sink for atmospheric carbon dioxide. Recent investigations have shown a large sensitivity of most phytoplankton organisms toward solar short-wavelength ultraviolet radiation (UV-B); even at ambient levels of UV-B radiation many organisms seem to be under UV stress. Because of their requirement for solar energy, the phytoplankton dwell in the top layers of the water column. In this near-surface position

  3. Vacuum vessel for thermonuclear device

    International Nuclear Information System (INIS)

    Kikuchi, Mitsuru; Nagashima, Keisuke; Suzuki, Masaru; Onozuka, Masaki.

    1997-01-01

    A vacuum vessel main body and structural members at the inside and the outside of the vacuum vessel main body are constituted by structural materials activated by irradiation of neutrons from plasmas such as stainless steels. Shielding members comprising tungsten or molybdenum are disposed on the surface of the vacuum vessel main body and the structural members of the inside and the outside of the main body. The shielding members have a function also as first walls or a seat member for the first walls. Armor tiles may be disposed to the shielding members. The shielding members and the armor tiles are secured to a securing seat member disposed, for example, to an inner plate of the vacuum vessel main body by bolts. Since the shielding members are disposed, it is not necessary to constitute the vacuum vessel main body and the structural members at the inside and the outside thereof by using a low activation material which is less activated, such as a titanium alloy. (I.N.)

  4. Cell-type-specific roles for COX-2 in UVB-induced skin cancer

    Science.gov (United States)

    Herschman, Harvey

    2014-01-01

    In human tumors, and in mouse models, cyclooxygenase-2 (COX-2) levels are frequently correlated with tumor development/burden. In addition to intrinsic tumor cell expression, COX-2 is often present in fibroblasts, myofibroblasts and endothelial cells of the tumor microenvironment, and in infiltrating immune cells. Intrinsic cancer cell COX-2 expression is postulated as only one of many sources for prostanoids required for tumor promotion/progression. Although both COX-2 inhibition and global Cox-2 gene deletion ameliorate ultraviolet B (UVB)-induced SKH-1 mouse skin tumorigenesis, neither manipulation can elucidate the cell type(s) in which COX-2 expression is required for tumorigenesis; both eliminate COX-2 activity in all cells. To address this question, we created Cox-2 flox/flox mice, in which the Cox-2 gene can be eliminated in a cell-type-specific fashion by targeted Cre recombinase expression. Cox-2 deletion in skin epithelial cells of SKH-1 Cox-2 flox/flox;K14Cre + mice resulted, following UVB irradiation, in reduced skin hyperplasia and increased apoptosis. Targeted epithelial cell Cox-2 deletion also resulted in reduced tumor incidence, frequency, size and proliferation rate, altered tumor cell differentiation and reduced tumor vascularization. Moreover, Cox-2 flox/flox;K14Cre + papillomas did not progress to squamous cell carcinomas. In contrast, Cox-2 deletion in SKH-1 Cox-2 flox/flox; LysMCre + myeloid cells had no effect on UVB tumor induction. We conclude that (i) intrinsic epithelial COX-2 activity plays a major role in UVB-induced skin cancer, (ii) macrophage/myeloid COX-2 plays no role in UVB-induced skin cancer and (iii) either there may be another COX-2-dependent prostanoid source(s) that drives UVB skin tumor induction or there may exist a COX-2-independent pathway(s) to UVB-induced skin cancer. PMID:24469308

  5. p85α mediates NFAT3-dependent VEGF induction in the cellular UVB response.

    Science.gov (United States)

    Dong, Wen; Li, Yi; Li, Xiaoguang; Hu, Meiru; Aodengqimuge; Sun, Li; Guo, Ning; Yuan, Shengtao; Song, Lun

    2013-03-15

    Exposure to solar ultraviolet B (UVB) radiation is known to induce several pathological reactions in the skin. In these processes, upregulation of VEGF expression has been demonstrated to be important in angiogenesis-associated photodamage and even skin cancers. However, the signaling events that are responsible for VEGF induction under UVB exposure have not been fully defined. Here, we demonstrate that the regulatory subunit of the phosphoinositide 3-kinase (PI3K), p85α, plays a role in mediating UVB-induced VEGF expression in mouse embryonic fibroblasts (MEFs) and mouse epithermal cells, the effect of which is unrelated to the PI3K activity. The transcriptional factor NFAT3 functions as a downstream target of p85α to mediate the induction of VEGF expression in the UVB response. Although lacking NFAT3-binding ability, p85α is required for the recruitment of NFAT3 to the NFAT-response element within the vegf promoter. Furthermore, by identifying the adjacent NFAT- and AP-1-binding sites within the vegf promoter, we also found an induced interaction between NFAT3 and one of the AP-1 components, c-Fos, after UVB irradiation. Without the aid of c-Fos, NFAT3 lost its vegf-promoter-binding ability. Taken together, our results reveal a novel PI3K-independent role for p85α in controlling VEGF induction during the cellular UVB response by regulating NFAT3 activity. Targeting p85α might be helpful for preventing UVB-induced angiogenesis and the associated photodamage.

  6. Antagonizing effects and mechanisms of afzelin against UVB-induced cell damage.

    Directory of Open Access Journals (Sweden)

    Seoung Woo Shin

    Full Text Available Ultraviolet (UV radiation induces DNA damage, oxidative stress, and inflammatory processes in human keratinocytes, resulting in skin inflammation, photoaging, and photocarcinogenesis. Adequate protection of skin against the harmful effects of UV irradiation is essential. Therefore, in this study, we investigated the protective effects of afzelin, one of the flavonoids, against UV irradiation in human keratinocytes and epidermal equivalent models. Spectrophotometric measurements revealed that the afzelin extinction maxima were in the UVB and UVA range, and UV transmission below 376 nm was <10%, indicating UV-absorbing activity of afzelin. In the phototoxicity assay using the 3T3 NRU phototoxicity test (3T3-NRU-PT, afzelin presented a tendency to no phototoxic potential. In addition, in order to investigate cellular functions of afzelin itself, cells were treated with afzelin after UVB irradiation. In human keratinocyte, afzelin effectively inhibited the UVB-mediated increase in lipid peroxidation and the formation of cyclobutane pyrimidine dimers. Afzelin also inhibited UVB-induced cell death in human keratinocytes by inhibiting intrinsic apoptotic signaling. Furthermore, afzelin showed inhibitory effects on UVB-induced release of pro-inflammatory mediators such as interleukin-6, tumor necrosis factor-α, and prostaglandin-E2 in human keratinocytes by interfering with the p38 kinase pathway. Using an epidermal equivalent model exposed to UVB radiation, anti-apoptotic activity of afzelin was also confirmed together with a photoprotective effect at the morphological level. Taken together, our results suggest that afzelin has several cellular activities such as DNA-protective, antioxidant, and anti-inflammatory as well as UV-absorbing activity and may protect human skin from UVB-induced damage by a combination of UV-absorbing and cellular activities.

  7. UV-B absorbing compounds in present-day and fossil pollen, spores, cuticles seed coats and wood: evaluation of a proxy for solar UV-B radiation.

    NARCIS (Netherlands)

    Rozema, J.; Blokker, P.; Mayoral Fuertes, M.; Broekman, R.A.

    2009-01-01

    UV-B absorbing compounds (UACs) in present-day and fossil pollen, spores, cuticles, seed coats and wood have been evaluated as a proxy for past UV. This proxy may not only provide information on variation of stratospheric ozone and solar UV in the period preceding and during the Antarctic ozone hole

  8. Carbon nanotubes based vacuum gauge

    Science.gov (United States)

    Rudyk, N. N.; Il’in, O. I.; Il’ina, M. V.; Fedotov, A. A.; Klimin, V. S.; Ageev, O. A.

    2017-11-01

    We have created an ionization type Vacuum gauge with sensor element based on an array of vertically aligned carbon nanotubes. Obtained asymmetrical current-voltage characteristics at different voltage polarity on the electrode with the CNTs. It was found that when applying a negative potential on an electrode with the CNTs, the current in the gap is higher than at a positive potential. In the pressure range of 1 ÷ 103 Torr vacuum gauge sensitivity was 6 mV/Torr (at a current of 4.5·10-5 A) and in the range of 10-5 ÷ 1 Torr was 10 mV/Torr (at a current of 1.3·10-5 A). It is shown that the energy efficiency of vacuum gauge can be increased in the case where electrode with CNT operates as an emitter of electrons.

  9. Horror, happenings and highlights in the history of vacuum physics

    Science.gov (United States)

    Kleint, Christian

    1998-12-01

    The origin of vacuum physics can be traced back to a statement of Aristotle that a vacuum cannot exist, which was questioned by Otto von Guericke. He tried to answer the question by experiment and was one of the most successful personalities to overcome medieval thought, and to pave the way to a new vistas for science and technology. His life and his famous demonstrations are described and a short account of the development of his apparatus and the impact on research in various countries is discussed. A list of old and newer reviews concludes the article.

  10. Ultraviolet-B (280-320 nm) absorbing pigments in the leaves of Silene vulgaris: their role in UV-B tolerance

    International Nuclear Information System (INIS)

    Staaij, J.W.M. van de; Ernst, W.H.O.; Hakvoort, H.W.J.; Rozema, J.

    1995-01-01

    The UV-B radiation tolerant perennial herb Silene vulgaris was tested on the influence of incident UV-B fluxes during growth on the synthesis of UV-B absorbing pigments in the leaves. Analysis of methanolic leaf extracts showed a stimulating effect of UV-B on the absorbing ability of leaf extracts. HPLC analysis made clear that UV-B radiation stimulated extractable flavonoid concentrations in leaves, but that UV-B absorption could only be partly attributed to these flavonoids. The contribution of flavonoids to UV-B absorption diminishes if plants mature. Other possible functions of flavonoids in plants growing under elevated UV-B conditions are discussed. (author)

  11. RhoB protects human keratinocytes from UVB-induced apoptosis through epidermal growth factor receptor signaling.

    Science.gov (United States)

    Canguilhem, Bruno; Pradines, Anne; Baudouin, Caroline; Boby, Céline; Lajoie-Mazenc, Isabelle; Charveron, Marie; Favre, Gilles

    2005-12-30

    Exposure of the skin to UVB light results in the formation of DNA photolesions that can give rise to cell death, mutations, and the onset of carcinogenic events. Specific proteins are activated by UVB and then trigger signal transduction pathways that lead to cellular responses. An alteration of these signaling molecules is thought to be a fundamental event in tumor promotion by UVB irradiation. RhoB, encoding a small GTPase has been identified as a DNA damage-inducible gene. RhoB is involved in epidermal growth factor (EGF) receptor trafficking, cytoskeletal organization, cell transformation, and survival. We have analyzed the regulation of RhoB and elucidated its role in the cellular response of HaCaT keratinocytes to relevant environmental UVB irradiation. We report here that the activated GTP-bound form of RhoB is increased rapidly within 5 min of exposure to UVB, and then RhoB protein levels increased concomitantly with EGF receptor (EGFR) activation. Inhibition of UVB-induced EGFR activation prevents RhoB protein expression and AKT phosphorylation but not the early activation of RhoB. Blocking UVB-induced RhoB expression with specific small interfering RNAs inhibits AKT and glycogen synthase kinase-3beta phosphorylation through inhibition of EGFR expression. Moreover, down-regulation of RhoB potentiates UVB-induced cell apoptosis. In contrast, RhoB overexpression protects keratinocytes against UVB-induced apoptosis. These results indicated that RhoB is regulated upon UVB exposure by a two-step process consisting of an early EGFR-independent RhoB activation followed by an EGFR-dependent induction of RhoB expression. Moreover, we have demonstrated that RhoB is essential in regulating keratinocyte cell survival after UVB exposure, suggesting its potential role in photocarcinogenesis.

  12. UV-B radiation-induced oxidative stress and p38 signaling pathway involvement in the benthic copepod Tigriopus japonicus.

    Science.gov (United States)

    Kim, Bo-Mi; Rhee, Jae-Sung; Lee, Kyun-Woo; Kim, Min-Jung; Shin, Kyung-Hoon; Lee, Su-Jae; Lee, Young-Mi; Lee, Jae-Seong

    2015-01-01

    Ultraviolet B (UV-B) radiation presents an environmental hazard to aquatic organisms. To understand the molecular responses of the intertidal copepod Tigriopus japonicus to UV-B radiation, we measured the acute toxicity response to 96 h of UV-B radiation, and we also assessed the intracellular reactive oxygen species (ROS) levels, glutathione (GSH) content, and antioxidant enzyme (GST, GR, GPx, and SOD) activities after 24 h of exposure to UV-B with LD50 and half LD50 values. Also, expression patterns of p53 and hsp gene families with phosphorylation of p38 MAPK were investigated in UV-B-exposed copepods. We found that the ROS level, GSH content, and antioxidant enzyme activity levels were increased with the transcriptional upregulation of antioxidant-related genes, indicating that UV-B induces oxidative stress by generating ROS and stimulating antioxidant enzymatic activity as a defense mechanism. Additionally, we found that p53 expression was significantly increased after UV-B irradiation due to increases in the phosphorylation of the stress-responsive p38 MAPK, indicating that UV-B may be responsible for inducing DNA damage in T. japonicus. Of the hsp family genes, transcriptional levels of hsp20, hsp20.7, hsp70, and hsp90 were elevated in response to a low dose of UV-B radiation (9 kJ m(-2)), suggesting that these hsp genes may be involved in cellular protection against UV-B radiation. In this paper, we performed a pathway-oriented mechanistic analysis in response to UV-B radiation, and this analysis provides a better understanding of the effects of UV-B in the intertidal benthic copepod T. japonicus. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. TNF-R1 and FADD mediate UVB-Induced activation of K+ channels in corneal epithelial cells

    Science.gov (United States)

    Boersma, Peter M.; Haarsma, Loren D.; Schotanus, Mark P.; Ubels, John L.

    2017-01-01

    The goal of this study was to elucidate the role of Fas, TNF-R1, FADD and cytochrome c in UVB-induced K+ channel activation, an early step in UVB-induced apoptosis, in human corneal limbal epithelial (HCLE) cells. HCLE cells were treated with Fas, TNF-R1 or FADD siRNA and exposed to 80 or 150 mJ/cm2 UVB. K+ channel activation and loss of intracellular K+ were measured using whole-cell patch-clamp recording and ion chromatography, respectively. Cytochrome c was measured with an ELISA kit. Cells in which Fas was knocked down exhibited identical UVB-induced K+ channel activation and loss of intracellular K+ to control cells. Cells in which TNF-R1 or FADD were knocked down demonstrated reduced K+ channel activation and decreased loss of intracellular K+ following UVB, relative to control cells. Application of TNF-α, the natural ligand of TNF-R1, to HCLE cells induced K+ channel activation and loss of intracellular K+. Cytochrome c was translocated to the cytosol by 2 h after exposure to 150 mJ/cm2 UVB. However, there was no release by 10 min post-UVB. The data suggest that UVB activates TNF-R1, which in turn may activate K+ channels via FADD. This conclusion is supported by the observation that TNF-α also causes loss of intracellular K+. This signaling pathway appears to be integral to UVB-induced K+ efflux, since knockdown of TNF-R1 or FADD inhibits the UVB-induced K+ efflux. The lack of rapid cytochrome c translocation indicates cytochrome c does not play a role in UVB-induced K+ channel activation. PMID:27818316

  14. Photoactivation of corticosteroids in UVB-exposed skin.

    Science.gov (United States)

    Miolo, G; Caffieri, S; Dalzoppo, D; Gallocchio, F; Fasani, E; Beyersbergen van Henegouwen, G M J

    2011-04-04

    The photodegradation of flumethasone (FM) and fluocinolone acetonide (FC) was studied in solution and in the pig skin. Both glucocorticosteroids applied to the pig skin were unstable under UVB light. The photoproducts formed in the skin were the lumi-, photolumi- and andro-derivatives for FM, the same found in vitro. Instead, FC hydroperoxide formed in solution was not found in the skin: the reactivity and oxidative ability of this photoproduct towards biological substrates (lipids, proteins) seems the reason of the lack of its detection in the ex vivo model. In fact, it demonstrated to quickly oxidize amino acids and peptides, and to react with BSA both in the dark and under irradiation. Moreover, the presence in the irradiated pig skin of the FC andro-derivative, which usually forms in H-donating environment, seems consistent with the mechanism of Norrish I fragmentation followed by H-abstraction, likely from the surrounding biological substrates. These findings indicate that photoreactivity of these compounds may take place in the skin of patients exposing themselves to sunlight and is a warning about possible skin damage as a result of that. Furthermore, photolability of these drugs in the skin might cause loss of their therapeutic activity. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Effects of ultraviolet-B radiation on fish: Histologic comparison of a UVB-sensitive and a UVB-tolerant species

    Science.gov (United States)

    Blazer, V.S.; Fabacher, D.L.; Little, E.E.; Ewing, M.S.; Kocan, K.M.

    1997-01-01

    Lahontan cutthroat trout Oncorhynchus clarki henshawi were sensitive to simulated solar ultraviolet-B radiation (UVB) and exhibited grossly visible signs of sunburn upon exposure. Razorback suckers Xyrauchen texanus, however, were tolerant to simulated solar UVB and showed no grossly visible signs of exposure. Cutthroat trout also had considerably less of an unidentified, possibly photoprotective, substance in the skin than did razorback suckers. In all attempt to characterize the cellular response to simulated solar UVB exposure in the skin of these two species, we examined sections from UVB-exposed fish by light and electron microscopy. Cutthroat trout showed grossly visible signs of sunburn by 48 h. Histologic observations included a sloughing of the mucous cells, necrosis and edema in the epidermis and dermis, and, in some cases, secondary fungal infections. Razorback suckers did not show any visible signs of sunburn during 72 h of experimental exposure. Histologic analyses revealed that cell necrosis had occurred, but the severe necrosis and sloughing noted in cutthroat trout was not observed. An increase in epidermal thickness, apparently due to hypertrophy and hyperplasia of large PAS-negative cells, occurred in the razorback suckers. These cells contained a large central region of low electron density and appeared to be club cells. In some, extensive interdigitation of the electron-lucent cytoplasm with adjacent epithelial cell margins occurred. Near the surface of the epidermis these cells were larger and the interface with epithelial cells lacked complex interdigitation. These cells may contain the substance that appears to protect razorback suckers against UV-B radiation.

  16. Objective validation of central sensitization in the rat UVB and heat rekindling model.

    Science.gov (United States)

    Weerasinghe, N S; Lumb, B M; Apps, R; Koutsikou, S; Murrell, J C

    2014-09-01

    The UVB and heat rekindling (UVB/HR) model shows potential as a translatable inflammatory pain model. However, the occurrence of central sensitization in this model, a fundamental mechanism underlying chronic pain, has been debated. Face, construct and predictive validity are key requisites of animal models; electromyogram (EMG) recordings were utilized to objectively demonstrate validity of the rat UVB/HR model. The UVB/HR model was induced on the heel of the hind paw under anaesthesia. Mechanical withdrawal thresholds (MWTs) were obtained from biceps femoris EMG responses to a gradually increasing pinch at the mid hind paw region under alfaxalone anaesthesia, 96 h after UVB irradiation. MWT was compared between UVB/HR and SHAM-treated rats (anaesthetic only). Underlying central mechanisms in the model were pharmacologically validated by MWT measurement following intrathecal N-methyl-d-aspartate (NMDA) receptor antagonist, MK-801, or saline. Secondary hyperalgesia was confirmed by a significantly lower pre-drug MWT {mean [±standard error of the mean (SEM)]} in UVB/HR [56.3 (±2.1) g/mm(2) , n = 15] compared with SHAM-treated rats [69.3 (±2.9) g/mm(2) , n = 8], confirming face validity of the model. Predictive validity was demonstrated by the attenuation of secondary hyperalgesia by MK-801, where mean (±SEM) MWT was significantly higher [77.2 (±5.9) g/mm(2) n = 7] in comparison with pre-drug [57.8 (±3.5) g/mm(2) n = 7] and saline [57.0 (±3.2) g/mm(2) n = 8] at peak drug effect. The occurrence of central sensitization confirmed construct validity of the UVB/HR model. This study used objective outcome measures of secondary hyperalgesia to validate the rat UVB/HR model as a translational model of inflammatory pain. © 2014 The Authors European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC®.

  17. Vacuum arc on the polycrystalline silica cathode

    Directory of Open Access Journals (Sweden)

    D. V. Duhopel'nikov

    2014-01-01

    Full Text Available Thin films of silica and its compounds are used in modern technology to produce Li-ion batteries, wear-resistant and protective coatings, thin-films insulators, etc. This coating is produced with CVD methods, with magnetron sputtering systems or with electron-beam evaporation. The vacuum arc evaporation method, presently, is not used.The paper demonstrates a possibility for a long-term operation of vacuum arc evaporator with polycrystalline silica-aluminum alloy (90% of silica cathode and with magnetic system to create a variable form of arch-like magnetic field on the cathode surface. It was shown that archlike configuration of magnetic field provides a stable discharge and uniform cathode spots moving with the velocities up to 5 m/s with magnetic fields induction about 10 mT. Thus, there is no local melting of the cathode, and this provides its long-term work without chips, cracks and destruction. Cathodes spots move over the cathode surface leaving t big craters with melted edges on its surface. The craters size was 150-450μm. The cathode spot movement character and the craters on the cathode surface were like the spots movement, when working on the copper or aluminum cathodes. With the magnetic field induction less than 1 mT, the cathode spots movement was the same as that of on the silica mono-crystal without magnetic field. Thus, the discharge volt-ampere characteristics for different values of magnetic fields were obtained. Voltampere characteristics were increasing and were shifted to the higher voltage with increasing magnetic field. The voltage was 18.7-26.5 V for the arc current 30-140 A.So, it was confirmed that vacuum arc evaporation method could be used for effective evaporation of silica and silica-based alloys and for thin films deposition of this materials.

  18. Stratospheric ozone depletion: high arctic tundra plant species from Svalbard are not affected by enhanced UV-B after 7 years of UV-B supplementation in the field.

    NARCIS (Netherlands)

    Rozema, J.; Boelen, P.; Blokker, P.; Callaghan, T.V.; Solheim, B.; Zielke, M.

    2006-01-01

    The response of tundra plants to enhanced UV-B radiation simulating 15 and 30% ozone depletion was studied at two high arctic sites (Isdammen and Adventdalen, 78° N, Svalbard).The set-up of the UV-B supplementation systems is described, consisting of large and small UV lamp arrays, installed in 1996

  19. Stratospheric ozone depletion: high arctic tundra plant growth on Svalbard is not affected by enhanced UV-B after 7 years of UV-B supplementation in the field.

    NARCIS (Netherlands)

    Rozema, J.; Boelen, P.; Solheim, B.; Zielke, M.; Buskens, A.; Doorenbosch, M.; Fijn, R.; Herder, J.; Callaghan, T.V.; Bjorn, L.O.; Gwynn-Jones, D.; Broekman, R.A.; Blokker, P.; van de Poll, W.

    2006-01-01

    The response of tundra plants to enhanced UV-B radiation simulating 15 and 30% ozone depletion was studied at two high arctic sites (Isdammen and Adventdalen, 78° N, Svalbard).The set-up of the UV-B supplementation systems is described, consisting of large and small UV lamp arrays, installed in 1996

  20. Stratospheric ozone depletion : High arctic tundra plant growth on Svalbard is not affected by enhanced UV-B after 7 years of UV-B supplementation in the field

    NARCIS (Netherlands)

    Rozema, Jelte; Boelen, P.; Solheim, B.; Zielke, M.; Buskens, A; Doorenbosch, M.; Fijn, R.; Herder, J.; Callaghan, T.; Bjoern, L.O.; Jones, D.G.; Broekman, R.; Blokker, P.; van de Poll, W.H.

    The response of tundra plants to enhanced UV-B radiation simulating 15 and 30% ozone depletion was studied at two high arctic sites (Isdammen and Adventdalen, 78 degrees N, Svalbard).The set-up of the UV-B supplementation systems is described, consisting of large and small UV lamp arrays, installed

  1. The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

    Science.gov (United States)

    Herkovits, J.; D’Eramo, J. L.; Fridman, O.

    2006-01-01

    The exposure of Bufo arenarum embryos to 300–310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m2 was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m2 at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure. PMID:16823076

  2. Effects of the ultraviolet-B radiation (UV-B) on conifers: a review

    International Nuclear Information System (INIS)

    Laakso, K.; Huttunen, S.

    1998-01-01

    The current knowledge on conifer responses to enhanced ultraviolet-B (UV-B) radiation is mainly based on greenhouse or growth chamber experiments of one growing season in duration. However, the biomass losses observed in greenhouses do not occur in field-grown trees in their natural habitats. Moreover, the majority of the 20 conifer species studied have been 1-year-old seedlings, and no studies have been undertaken on mature trees. Fully grown needles, with their glaucous waxy surfaces and thick epidermal cells with both soluble and wall-bound UV-B screening metabolites, are well protected against UV-B radiation. However, it is not known whether these are sufficient protectants in young emerging needles or during the early spring period of high UV-B levels reflected from snow. In order to understand all the mechanisms that result in the protection of conifer needles against UV-B radiation, future research should focus on the epidermal layer, separating the waxes, cuticle and epidermal and hypodermal cells. Parallel studies should consist of wall-bound and soluble secondary metabolite analysis, antioxidant measurements and microscopic observations. (author)

  3. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    Directory of Open Access Journals (Sweden)

    Lara S. eGarcia-Corral

    2015-07-01

    Full Text Available The Mediterranean Sea is a vulnerable region for climate change, warming at higher rates compare to the global ocean. Warming leads to increased stratification of the water column and enhanced the oligotrophic nature of the Mediterranean Sea. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely enhancing impacts to biota.Here we experimentally elucidate the cumulative effects of warming and natural UV-B radiation on the net community production (NCP of plankton communities. We conducted five experiments at monthly intervals, from June to October 2013, and evaluated the responses of NCP to ambient UV-B radiation and warming (+3ºC, alone and in combination, in a coastal area of the northwest Mediterranean Sea. UV-B radiation and warming lead to reduced net community production and resulted in a heterotrophic (NCP<0 metabolic balance. Both UV-B radiation and temperature, showed a significant individual effect in NCP across treatments and time. However, their joint effect showed to be synergistic as the interaction between them (UV x Temp was statistically significant in most of the experiments performed. Our results showed that both drivers, would affect the gas exchange of CO2-O2 from and to the atmosphere and the role of plankton communities in the Mediterranean carbon cycle

  4. UVA and UVB in sunlight, Optimal Utilization of UV rays in Sunlight for phototherapy

    Directory of Open Access Journals (Sweden)

    Balasaraswathy P

    2002-01-01

    Full Text Available The disadvantages of sunlight as the source of UVA for phototherapy include variation with time, place, season, and atmospheric conditions. In the present study at Coimbatore, India we measured the UVa and UVB irradiance for one year using PMA 2100 meter. UVB irradiance was mazimum between 12.00 noon- 1.00 p.m (19.50µw/cm2 to 40.2µw/cm2 and UVA between 12 noon-1.15 p.m. (4.70mw/cm2 tp 6.59mw/cm2. The ratio of UVA was 1:500 to 1:600 during early hours and late evening and 1:200 during mid-day. At peak time (11.30 a.m. to 1.30 p.m., the exposure time for 1 June of UVA was 2 min. 32 sec. to 4 min. 31 sec and for 10mj of UVB it was from 4 min. 55 sec. to 11 min. 22 sec. We recommend the ideal time for UVB phototheraphy between 11.00 a.m. to 2.00 p.m. and for PUVASOL between 9.30 a.m. to 11 a.m. and 2 p.m. to 3.30 p.m. when incidental UVB and infrared rays responsible for heat are less.

  5. UVA and UVB in sunlight, optimal utilization of UV rays in sunlight for phototherapy.

    Science.gov (United States)

    Balasaraswathy, P; Kumar, Udaya; Srinivas, C R; Nair, Shashidharan

    2002-01-01

    The disadvantages of sunlight as the source of UVA for phototherapy include variation with time, place, season, and atmospheric conditions. In the present study at Coimbatore, India we measured the UVa and UVB irradiance for one year using PMA 2100 meter. UVB irradiance was maximum between 12.00 noon-1.00 p.m (19.50 microw/cm2 to 40.2 microw/cm2) and UVA between 12 noon-1.15 p.m. (4.70 mw/cm2 tp 6.59 mw/cm2). The ratio of UVA was 1:500 to 1:600 during early hours and late evening and 1:200 during mid-day. At peak time (11.30 a.m. to 1.30 p.m.), the exposure time for 1 June of UVA was 2 min. 32 sec. to 4 min. 31 sec and for 10 mj of UVB it was from 4 min. 55 sec. to 11 min. 22 sec. We recommend the ideal time for UVB phototheraphy between 11.00 a.m. to 2.00 p.m. and for PUVASOL between 9.30 a.m. to 11 a.m. and 2 p.m. to 3.30 p.m. when incidental UVB and infrared rays responsible for heat are less.

  6. Adiponectin Suppresses UVB-Induced Premature Senescence and hBD2 Overexpression in Human Keratinocytes.

    Directory of Open Access Journals (Sweden)

    MinJeong Kim

    Full Text Available Recent studies have revealed that adiponectin can suppress cellular inflammatory signaling pathways. This study aimed to elucidate the effect of adiponectin on the unregulated production of hBD2 in UVB-induced premature senescent keratinocytes. We constructed an in vitro model of premature senescent keratinocytes through repeated exposure to low energy UVB. After repeated low energy UVB exposure, there was significant generation of reactive oxygen species (ROS and induction of senescence-associated markers, including senescence associated beta-galactosidase activity and expression of p16INK4a and histone H2AX. In addition, the present clinical study showed higher expression of hBD2 in sun-exposed skin of elderly group, and the overexpression of hBD2 was observed by c-Fos activation in vitro. Adiponectin has the ability to scavenge ROS and consequently inhibit MAPKs and SA-markers in UVB-exposed keratinocytes. An inhibitor study demonstrated that adiponectin downregulated hBD2 mRNA expression through suppression of the AP-1 transcription factor components c-Fos via inactivation of p38 MAPK. Collectively, the dysregulated production of hBD2 by the induction of oxidative stress was attenuated by adiponectin through the suppression of p38 and JNK/SAPK MAPK signaling in UVB-mediated premature senescent inducible conditions. These results suggest the feasibility of adiponectin as an anti-photoaging and anti-inflammatory agent in the skin.

  7. Experimental assessment of cumulative temperature and UV-B radiation effects on Mediterranean plankton metabolism

    KAUST Repository

    Garcia-Corral, Lara S.

    2015-07-07

    The Mediterranean Sea is a vulnerable region for climate change, warming at higher rates compare to the global ocean. Warming leads to increased stratification of the water column and enhanced the oligotrophic nature of the Mediterranean Sea. The oligotrophic waters are already highly transparent, however, exposure of Mediterranean plankton to ultraviolet radiation (UV-B and UV-A) may increase further if the waters become more oligotrophic, thereby, allowing a deeper UV radiation penetration and likely enhancing impacts to biota. Here we experimentally elucidate the cumulative effects of warming and natural UV-B radiation on the net community production (NCP) of plankton communities. We conducted five experiments at monthly intervals, from June to October 2013, and evaluated the responses of NCP to ambient UV-B radiation and warming (+3°C), alone and in combination, in a coastal area of the northwest Mediterranean Sea. UV-B radiation and warming lead to reduced NCP and resulted in a heterotrophic (NCP < 0) metabolic balance. Both UV-B radiation and temperature, showed a significant individual effect in NCP across treatments and time. However, their joint effect showed to be synergistic as the interaction between them (UV × Temp) was statistically significant in most of the experiments performed. Our results showed that both drivers, would affect the gas exchange of CO2−O2 from and to the atmosphere and the role of plankton communities in the Mediterranean carbon cycle.

  8. Yellowing of fresh-cut spinach (Spinacia oleracea L. leaves delayed by UV-B applications

    Directory of Open Access Journals (Sweden)

    M. Ufuk Kasım

    2017-09-01

    Full Text Available In present work, the effects of UV-B treatments on quality of fresh-cut spinach leaves were studied. For this purpose, spinach leaves grown in glasshouse were harvest, cleaned and placed into polystyrene foam dishes and wrapped by stretch film. After packaging, fresh-cut spinach leaves were treated with UV-B irradiation and were stored at 5 °C temperature for 12 days. Total soluble solids, visual quality, L∗a∗b∗ values, and also hue angle values of samples were determined during storage. Total soluble solids content of samples in control group has been higher than those from samples in UV-B treatments, however, visual quality was lower than the other treatments. According to L∗ values of the samples, it is found that lower ultraviolet irratiation (UV-B treatments caused yellowing of samples, and also same result was obtained by b∗ and a∗ values of fresh-cut spinach leaves. Similarly, hue angles values of samples treated with UV-B for 6 min was higher compared with the other treatments. Consequently, yellowing of fresh-cut spinach leaves was decreased, and visual quality scores of samples was increased through ultraviolet irradiation treatments.

  9. Very Low-Cost, Rugged, High-Vacuum System for Mass Spectrometers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA, DoD, DHS, and commercial industry have a pressing need for miniaturized, rugged, low-cost high-vacuum systems. Recent advances in sensor technology at NASA and...

  10. Very Low-Cost, Rugged, High-Vacuum System for Mass Spectrometers, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA, the DoD, DHS, and commercial industry have a pressing need for miniaturized, rugged, low-cost, high vacuum systems. Recent advances in sensor technology at...

  11. Vacuum-assisted drainage in cardiopulmonary bypass: advantages and disadvantages

    Science.gov (United States)

    de Carvalho Filho, Élio Barreto; Marson, Fernando Augusto de Lima; da Costa, Loredana Nilkenes Gomes; Antunes, Nilson

    2014-01-01

    Systematic review of vacuum assisted drainage in cardiopulmonary bypass, demonstrating its advantages and disadvantages, by case reports and evidence about its effects on microcirculation. We conducted a systematic search on the period 1997-2012, in the databases PubMed, Medline, Lilacs and SciELO. Of the 70 selected articles, 26 were included in the review. Although the vacuum assisted drainage has significant potential for complications and requires appropriate technology and professionalism, prevailed in literature reviewed the concept that vacuum assisted drainage contributed in reducing the rate of transfusions, hemodilutions, better operative field, no significant increase in hemolysis, reduced complications surgical, use of lower prime and of smaller diameter cannulas. PMID:25140478

  12. Development and Measurement of Strain Free RF Photoinjector Vacuum Windows

    CERN Document Server

    Biedron, Sandra G

    2004-01-01

    RF photoinjectors produce the highest brightness electron bunches only under nearly ideal illumination by a drive laser. The vacuum window used to introduce the laser beam is an essential element that may potentially degrade any distribution, making it difficult or impossible to know the actual uniformity achieved at the cathode. Because of the necessity to obtain ultrahigh vacuum near the photoinjector, some restrictions are imposed on the fabrication technology available to manufacture distortion-free windows. At the UV wavelengths commonly used for photoinjectors, it is challenging to measure and eliminate degradation caused by vacuum windows. Here, we discuss the initial laser-based measurements of a strain-free, coated, UHV window manufactured by Insulator Seal in collaboration with members of Brookhaven and Argonne National Laboratories.

  13. Economical evaluation of damaged vacuum insulation panels in buildings

    Science.gov (United States)

    Kim, Y. M.; Lee, H. Y.; Choi, G. S.; Kang, J. S.

    2015-12-01

    In Korea, thermal insulation standard of buildings have been tightened annually to satisfy the passive house standard from the year 2009. The current domestic policies about disseminating green buildings are progressively conducted. All buildings should be the zero energy building in the year 2025, obligatorily. The method is applied to one of the key technologies for high-performance insulation for zero energy building. The vacuum insulation panel is an excellent high performance insulation. But thermal performance of damaged vacuum insulation panels is reduced significantly. In this paper, the thermal performance of damaged vacuum insulation panels was compared and analyzed. The measurement result of thermal performance depends on the core material type. The insulation of building envelope is usually selected by economic feasibility. To evaluate the economic feasibility of VIPs, the operation cost was analyzed by simulation according to the types and damaged ratio of VIPs

  14. A squeezed light source operated under high vacuum.

    Science.gov (United States)

    Wade, Andrew R; Mansell, Georgia L; Chua, Sheon S Y; Ward, Robert L; Slagmolen, Bram J J; Shaddock, Daniel A; McClelland, David E

    2015-12-14

    Non-classical squeezed states of light are becoming increasingly important to a range of metrology and other quantum optics applications in cryptography, quantum computation and biophysics. Applications such as improving the sensitivity of advanced gravitational wave detectors and the development of space-based metrology and quantum networks will require robust deployable vacuum-compatible sources. To date non-linear photonics devices operated under high vacuum have been simple single pass systems, testing harmonic generation and the production of classically correlated photon pairs for space-based applications. Here we demonstrate the production under high-vacuum conditions of non-classical squeezed light with an observed 8.6 dB of quantum noise reduction down to 10 Hz. Demonstration of a resonant non-linear optical device, for the generation of squeezed light under vacuum, paves the way to fully exploit the advantages of in-vacuum operations, adapting this technology for deployment into new extreme environments.

  15. Vacuum chambers full of ideas for the Swedish synchrotron

    CERN Multimedia

    Corinne Pralavorio

    2016-01-01

    CERN’s Vacuum, Surfaces and Coatings group has contributed to the development of vacuum chambers for the MAX IV synchrotron, which has just been officially opened in Sweden.   A section of the new 3 GeV MAX IV synchrotron at the time of installation. In the centre of the magnets you can see the vacuum chamber developed in collaboration with CERN. (Photo: Marek Grabski, MAX IV Vacuum group) On 21 June, the King and the Prime Minister of Sweden officially opened MAX IV, a brand-new synchrotron in Lund, Sweden. The summer solstice, the longest day of the year, was deliberately chosen for the ceremony: MAX IV, a cutting-edge synchrotron, will deliver the brightest X-rays ever produced to more than 2000 users. Some 1500 kilometres away, a team at CERN followed the opening ceremony with a touch of pride. The Vacuum, Surfaces and Coatings group in the Technology department (TE-VSC) participated in the construction of this new synchrotron. Its contribution lies at the very hea...

  16. Treatment of vitiligo vulgaris with narrow-band UVB and oral Polypodium leucotomos extract: a randomized double-blind placebo-controlled study

    NARCIS (Netherlands)

    Middelkamp-Hup, M. A.; Bos, J. D.; Rius-Diaz, F.; Gonzalez, S.; Westerhof, W.

    2007-01-01

    Background The first choice treatment for vitiligo vulgaris is narrow-band UVB (NB-UVB), but no satisfactory treatment exists. Objectives To investigate if Polypodium leucotomos, an antioxidative and immunomodulatory plant extract, improves NB-UVB-induced repigmentation. Methods Fifty patients with

  17. Inclusion of an ultraviolet radiation transfer component in an urban forest effects model for predicting tree influences on potential below-canopy exposure to UVB radiation

    Science.gov (United States)

    Gordon M. Heisler; Richard H. Grant; David J. Nowak; Wei Gao; Daniel E. Crane; Jeffery T. Walton

    2003-01-01

    Evaluating the impact of ultraviolet-B radiation (UVB) on urban populations would be enhanced by improved predictions of the UVB radiation at the level of human activity. This paper reports the status of plans for incorporating a UVB prediction module into an existing Urban Forest Effects (UFORE) model. UFORE currently has modules to quantify urban forest structure,...

  18. Vacuum assisted closure in coloproctology

    NARCIS (Netherlands)

    Bemelman, W. A.

    2009-01-01

    Vacuum-assisted closure has earned its indications in coloproctology. It has been described with variable results in the treatment of large perineal defects after abdominoperineal excision, in the treatment of stoma dehiscence and perirectal abscesses. The most promising indication for

  19. Brine Distribution after Vacuum Saturation

    DEFF Research Database (Denmark)

    Hedegaard, Kathrine; Andersen, Bertel Lohmann

    1999-01-01

    Experiments with the vacuum saturation method for brine in plugs of chalk showed that a homogeneous distribution of brine cannot be ensured at saturations below 20% volume. Instead of a homogeneous volume distribution the brine becomes concentrated close to the surfaces of the plugs...

  20. Vacuum Stability of Standard Model^{++}

    CERN Document Server

    Anchordoqui, Luis A.; Goldberg, Haim; Huang, Xing; Lust, Dieter; Taylor, Tomasz R.; Vlcek, Brian

    2013-01-01

    The latest results of the ATLAS and CMS experiments point to a preferred narrow Higgs mass range (m_h \\simeq 124 - 126 GeV) in which the effective potential of the Standard Model (SM) develops a vacuum instability at a scale 10^{9} -10^{11} GeV, with the precise scale depending on the precise value of the top quark mass and the strong coupling constant. Motivated by this experimental situation, we present here a detailed investigation about the stability of the SM^{++} vacuum, which is characterized by a simple extension of the SM obtained by adding to the scalar sector a complex SU(2) singlet that has the quantum numbers of the right-handed neutrino, H", and to the gauge sector an U(1) that is broken by the vacuum expectation value of H". We derive the complete set of renormalization group equations at one loop. We then pursue a numerical study of the system to determine the triviality and vacuum stability bounds, using a scan of 10^4 random set of points to fix the initial conditions. We show that, if there...

  1. PC driven integrated vacuum system

    International Nuclear Information System (INIS)

    Curuia, M.; Culcer, M.; Brandea, I.; Anghel, M.

    2001-01-01

    The paper presents a integrated vacuum system which was designed and manufactured in our institute. The main parts of this system are the power supply unit for turbo-melecular pumps and the vacuummeter. Both parts of the system are driven by means of a personal computer using a serial communication, according to the RS 232 hardware standard.(author)

  2. Filling the vacuum at LHCb

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    Last month, the Vacuum, Surfaces and Coatings (VSC) group was tasked with an unusually delicate operation in the LHCb experiment cavern: removing the LHC beam pipe while keeping the sensitive Vertex Locator vacuum vessel (VELO) completely isolated from the action.   The VSC group seal off the VELO beam pipe with a flange. Image: Gloria Corti. LHCb’s VELO detector is one of the crown jewels of the experiment. With detector elements surrounded by a vacuum, it gets as close as 5 cm from the beam. Fantastic for physics, but difficult for all-important access. “Because of the sensitivity of the VELO detector and its proximity to the beam, the collaboration decided not to bake (see box) its portion of the beam pipe,” says Giulia Lanza (TE-VSC-LBV), the expert in charge of the beam vacuum operation. “Our group was therefore asked to remove the rest of the LHC beam pipe while keeping the VELO portion of the pipe completely isolated. This work...

  3. The Training Employment Vacuum Cycle

    Science.gov (United States)

    Hansen, Carl E.

    1970-01-01

    This program suggests: (1) take the underemployed, nonskilled worker, who has a feel for upward job mobility, and offer him opportunities of current job training programs; (2) fill the vacuum he creates by filling his job with hard core unemployed individual; (3) after he has worked for a period of time the cycle will probably start over. (Author)

  4. Variations in constitutive and inducible UV-B tolerance; dissecting photosystem II protection in Arabidopsis thaliana accessions

    NARCIS (Netherlands)

    Jansen, M.A.K.; LeMartret, B.; Koornneef, M.

    2010-01-01

    The rise in ultraviolet-B (UV-B) (280–315 nm) radiation levels, that is a consequence of stratospheric ozone layer depletion, has triggered extensive research on the effects of UV-B on plants. Plants raised under natural sunlight conditions are generally well protected from the potentially harmful

  5. Extended UVB Exposures Alter Tumorigenesis and Treatment Efficacy in a Murine Model of Cutaneous Squamous Cell Carcinoma

    International Nuclear Information System (INIS)

    Burns, E. M.; Tober, K. L.; Riggenbach, J. A.; Oberyszyn, T. M.; Kusewitt, D. F.; Young, G. S.

    2013-01-01

    Epidemiological studies support a link between cumulative sun exposure and cutaneous squamous cell carcinoma (SCC) development. However, the presumed effects of extended ultraviolet light B (UVB) exposure on tumorigenesis in the sexes have not been formally investigated. We examined differences in ultimate tumorigenesis at 25 weeks in mice exposed to UVB for either 10 or 25 weeks. Additionally, we investigated the effect of continued UVB exposure on the efficacy of topical treatment with anti-inflammatory (diclofenac) or antioxidant (C E Ferulic or vitamin E) compounds on modulating tumorigenesis. Vehicle-treated mice in the 25-week UVB exposure model exhibited an increased tumor burden and a higher percentage of malignant tumors compared to mice in the 10-week exposure model, which correlated with increases in total and mutant p53-positive epidermal cells. Only topical diclofenac decreased tumor number and burden in both sexes regardless of UVB exposure length. These data support the commonly assumed but not previously demonstrated fact that increased cumulative UVB exposure increases the risk of UVB-induced SCC development and can also affect therapeutic efficacies. Our study suggests that cessation of UVB exposure by at-risk patients may decrease tumor development and that topical NSAIDs such as diclofenac may be chemo preventive.

  6. RESPONSE OF OXIDATIVE STRESS DEFENSE SYSTEMS IN RICE (ORYZA SATIVA) LEAVES WITH SUPPLEMENTAL UV-B RADIATION

    Science.gov (United States)

    The impact of elevated ultraviolet-B radiation (UV-B, 280-320 nm) on membrane systems and lipid peroxidation, and possible involvement of active oxygen radicals was investigated in leaves of two UV-B susceptible rice cultivars (Oryza sativa L. cvs IR74 and Dular). Rice seedlings ...

  7. Effect of increased UV-B radiation on carotenoid accumulation and total antioxidant capacity in tobacco (Nicotiana tabacum L.) leaves.

    Science.gov (United States)

    Shen, J; Jiang, C Q; Yan, Y F; Liu, B R; Zu, C L

    2017-03-08

    Carotenoids are important components of plant antioxidant systems, which protect photosystems from photooxidative destruction during ultraviolet-B (UV-B) exposure. The influence of carotenoids on total antioxidant capacity (TAC) of plants has rarely been studied. In this study, tobacco (Nicotiana tabacum L., 'K326') seedlings exposed to UV-B radiation were used in order to evaluate the effects of ambient levels of UV-B radiation on carotenoid accumulation. The aim was to investigate whether carotenoids could enhance TAC as a means of UV protection. Our results showed that leaf carotenoid content in the low UV-B exposure (+9.75 μW/cm 2 ) plants was approximately 8% higher than that observed in control plants at 2-8 days of exposure. At high UV-B exposure (+20.76 μW/cm 2 ), the carotenoid content increased rapidly after 1 day's exposure (10.41% higher than the control), followed by a return to the content as in control plants. Furthermore, carotenoid content positively correlated with TAC (P = 0.024). These results suggest that carotenoids have antioxidant properties and play an important role in the antioxidant system. UV-B exposure increased the carotenoid synthesis capability of plants. The plants could deplete the carotenoids to scavenge excess ROS at high UV-B radiation levels, which protects the tobacco plant from oxidative damage caused by UV-B stress.

  8. Solar UV-B and visible radiation in tropical forest gaps: measurements partitioning direct and diffuse radiation

    International Nuclear Information System (INIS)

    Flint, S.D.; Caldwell, M.M.

    1998-01-01

    Solar ultraviolet-B (UV-B) radiation penetrates plant canopies to a different degree than photosynthetically active radiation (PAR) because UV-B is diffused to a greater degree by the atmosphere. We measured both global (total) and diffuse solar radiation in canopy gaps of a semideciduous tropical forest in Panama. Measurements were simultaneously made in the UV-B and PAR wavebands. Compared to unobstructed measurements taken outside the forest, the sunlit portions of gaps were depleted in the proportion of UV-B relative to PAR, especially at midday. Shaded areas, in contrast, were always richer in UV-B relative to PAR, but the magnitude of the change varied greatly. Presumably this variation was due to the differences in the directional nature of diffuse solar UV-B radiation as compared to diffuse PAR. Measurements in the gaps showed substantial reductions in the proportion of radiation in the diffuse components of both the UV-B and PAR wavebands. However, because of the greater proportion of UV-B which is diffuse, it tended to predominate in shaded areas. Similar patterns were seen in measurements taken at temperate latitudes. Response of shade- and gap-dwelling plants to these high UV-B:PAR ratios has received little attention. (author)

  9. The effect of epidermal levels of urocanic acid on 25-hydroxyvitamin D synthesis and inflammatory mediators upon narrowband UVB irradiation

    NARCIS (Netherlands)

    Landeck, Lilla; Jakasa, Ivone; Dapic, Irena; Lutter, René; Thyssen, Jacob P.; Skov, Lone; Braun, Andrea; Schön, Michael P.; John, Swen M.; Kezic, Sanja; Brans, Richard

    2016-01-01

    Urocanic acid (UCA) absorbs ultraviolet (UV)B radiation in the epidermis which may interfere with phototherapy. Therefore, the influence of individual levels of UCA on immune reactivity and vitamin D synthesis induced by narrowband UVB radiation was assessed. Twenty-eight subjects with irritant

  10. LHC Detector Vacuum System Consolidation for Long Shutdown 1 (LS1) in 2013-2014

    CERN Document Server

    Gallilee, M; Cruikshank, P; Gallagher, J; Garion, C; Jimenez, J M; Kersevan, R; Kos, H; Leduc, L; Lepeule, P; Provot, N; Rambeau, H; Veness, R

    2012-01-01

    The LHC has ventured into unchartered territory for Particle Physics accelerators. A dedicated consolidation program is required between 2013 and 2014 to ensure optimal physics performance. The experiments, ALICE, ATLAS, CMS, and LHCb, will utilise this shutdown, along with the gained experience of three years of physics running, to make optimisations to their detectors. New vacuum technologies have been developed for the experimental areas, to be integrated during this first phase shutdown. These technologies include bellows, vacuum chambers and ion pumps in aluminium, new beryllium vacuum chambers, and composite mechanical supports. An overview of this first phase consolidation program for the LHC experiments is presented.

  11. Effect of enhanced UV-B radiation on pollen quantity, quality, and seed yield in Brassica rapa (Brassicaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Demchik, S.M.; Day, T.A. [West Virginia Univ., Morgantown, WV (United States)

    1996-05-01

    Three experiments examined the influence of ultraviolet-B radiation (UV-B; 280-320 nm) exposure on reproduction in Brassica rapa (Brassicacaeae). Plants were grown in a greenhouse under three biologically effective UV-B levels that stimulated either an ambient stratospheric ozone level (control), 16% ({open_quotes}low enhanced{close_quotes}), or 32% ({open_quotes}high enhanced{close_quotes}) ozone depletion levels at Morgantown, WV, USA in mid-March. In the first experiment,pollen production and viability per flower were reduced by {approx}50% under both enhanced UV-B levels relative to ambient controls. While plants under high-enhanced UV-B produced over 40% more flowers than plants under the two lower UV-B treatments, whole-plant production of viable pollen was reduced under low-enhanced UV-B to 34% of ambient controls. In the second experiment, the influence of source-plant UV-B exposure on in vitro pollen from plants was examined and whether source-plant UV-B exposure influenced in vitro pollen germination and viability. Pollen from plants under both enhanced-UV-B was reduced from 65 to 18%. Viability of the pollen from plants grown under both enhanced UV-B treatments was reduced to a much lesser extent: only from {approx}43 to 22%. Thus, ambient source-plant pollen was more sensitive to enhanced UV-B levels to fertilize plants growing under ambient-UV-B levels, and assessed subsequent seed production and germination. Seed abortion rates were higher in plants pollinated with pollen from the enhanced UV-B treatments, than from ambient UV-B. Despite this, seed yield (number and mass) per plant was similar, regardless of the UV-B exposure of their pollen source. Our findings demonstrate that enhanced UV-B levels associated with springtime ozone depletion events have the capacity to substantially reduce viable pollen production, and could ultimately reduce reproductive success of B. rapa. 37 refs., 4 figs., 2 tabs.

  12. Effect of enhanced UV-B radiation on pollen quantity, quality, and seed yield in Brassica rapa (Brassicaceae)

    International Nuclear Information System (INIS)

    Demchik, S.M.; Day, T.A.

    1996-01-01

    Three experiments examined the influence of ultraviolet-B radiation (UV-B; 280-320 nm) exposure on reproduction in Brassica rapa (Brassicacaeae). Plants were grown in a greenhouse under three biologically effective UV-B levels that stimulated either an ambient stratospheric ozone level (control), 16% (open-quotes low enhancedclose quotes), or 32% (open-quotes high enhancedclose quotes) ozone depletion levels at Morgantown, WV, USA in mid-March. In the first experiment,pollen production and viability per flower were reduced by ∼50% under both enhanced UV-B levels relative to ambient controls. While plants under high-enhanced UV-B produced over 40% more flowers than plants under the two lower UV-B treatments, whole-plant production of viable pollen was reduced under low-enhanced UV-B to 34% of ambient controls. In the second experiment, the influence of source-plant UV-B exposure on in vitro pollen from plants was examined and whether source-plant UV-B exposure influenced in vitro pollen germination and viability. Pollen from plants under both enhanced-UV-B was reduced from 65 to 18%. Viability of the pollen from plants grown under both enhanced UV-B treatments was reduced to a much lesser extent: only from ∼43 to 22%. Thus, ambient source-plant pollen was more sensitive to enhanced UV-B levels to fertilize plants growing under ambient-UV-B levels, and assessed subsequent seed production and germination. Seed abortion rates were higher in plants pollinated with pollen from the enhanced UV-B treatments, than from ambient UV-B. Despite this, seed yield (number and mass) per plant was similar, regardless of the UV-B exposure of their pollen source. Our findings demonstrate that enhanced UV-B levels associated with springtime ozone depletion events have the capacity to substantially reduce viable pollen production, and could ultimately reduce reproductive success of B. rapa. 37 refs., 4 figs., 2 tabs

  13. Vacuum polarization and Hawking radiation

    Science.gov (United States)

    Rahmati, Shohreh

    Quantum gravity is one of the interesting fields in contemporary physics which is still in progress. The purpose of quantum gravity is to present a quantum description for spacetime at 10-33cm or find the 'quanta' of gravitational interaction.. At present, the most viable theory to describe gravitational interaction is general relativity which is a classical theory. Semi-classical quantum gravity or quantum field theory in curved spacetime is an approximation to a full quantum theory of gravity. This approximation considers gravity as a classical field and matter fields are quantized. One interesting phenomena in semi-classical quantum gravity is Hawking radiation. Hawking radiation was derived by Stephen Hawking as a thermal emission of particles from the black hole horizon. In this thesis we obtain the spectrum of Hawking radiation using a new method. Vacuum is defined as the possible lowest energy state which is filled with pairs of virtual particle-antiparticle. Vacuum polarization is a consequence of pair creation in the presence of an external field such as an electromagnetic or gravitational field. Vacuum polarization in the vicinity of a black hole horizon can be interpreted as the cause of the emission from black holes known as Hawking radiation. In this thesis we try to obtain the Hawking spectrum using this approach. We re-examine vacuum polarization of a scalar field in a quasi-local volume that includes the horizon. We study the interaction of a scalar field with the background gravitational field of the black hole in the desired quasi-local region. The quasi-local volume is a hollow cylinder enclosed by two membranes, one inside the horizon and one outside the horizon. The net rate of particle emission can be obtained as the difference of the vacuum polarization from the outer boundary and inner boundary of the cylinder. Thus we found a new method to derive Hawking emission which is unitary and well defined in quantum field theory.

  14. Protection of riboflavin and UVB sensitized degradation of DNA and RNA bases by natural antioxidants.

    Science.gov (United States)

    Joshi, Prakash C; Gray, Thomas A; Keane, Thomas C

    2012-04-01

    Riboflavin (RF) is a potent photosensitizer producing extensive degradation of purine and pyrimidine derivatives of nucleic acids under UVA, UVB and sunlight. In this study we have demonstrated that reactive O(2) species generated by photosensitized RF under UVB were responsible for the degradation of DNA and RNA bases. While (1)O(2) accounted for the degradation of adenine, guanine, thymine and uracil, O(2)(-·)also contributed to partial degradation of adenine. Cytosine remained unaffected by the synergistic action of RF and UVB. Ascorbic acid, glutathione, glycolic acid and quercetin showed remarkable protection (88-100%) against photodegradation of bases. Sorbitol was effective in preventing photodegradation of guanine. These naturally occurring antioxidants are potential candidates for prevention against oxidative stress caused by photosensitization. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Effects of enhanced UV-B radiation on Mentha spicata essential oils

    International Nuclear Information System (INIS)

    Karousou, R.; Grammatikopoulos, G.; Lanaras, T.; Manetas, Y.; Kokkini, S.

    1998-01-01

    In vitro propagated plantlets representing two distinct chemotypes of Mentha spicata, viz. plants producing essential oils rich in piperitone oxide and piperitenone oxide (chemotype I) and rich in carvone and dihydrocarvone (chemotype II), were grown in the field under ambient or ambient plus supplemental UV-B radiation, biologically equivalent to a 15% ozone depletion over Patras (38.3°N, 29.1°E), Greece. Enhanced UV-B radiation stimulated essential oil production in chemotype II substantially, while a similar, non-significant trend was observed in chemotype I. No effect was found on the qualitative composition of the essential oils, whereas the quantitative composition was slightly modified in chemotype I. This is the first investigation reporting an improved essential oil content under UV-B supplementation in aromatic plants under field conditions

  16. UV-B detected by the UVR8 photoreceptor antagonizes auxin signaling and plant shade avoidance.

    Science.gov (United States)

    Hayes, Scott; Velanis, Christos N; Jenkins, Gareth I; Franklin, Keara A

    2014-08-12

    Plants detect different facets of their radiation environment via specific photoreceptors to modulate growth and development. UV-B is perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8). The molecular mechanisms linking UVR8 activation to plant growth are not fully understood, however. When grown in close proximity to neighboring vegetation, shade-intolerant plants initiate dramatic stem elongation to overtop competitors. Here we show that UV-B, detected by UVR8, provides an unambiguous sunlight signal that inhibits shade avoidance responses in Arabidopsis thaliana by antagonizing the phytohormones auxin and gibberellin. UV-B triggers degradation of the transcription factors PHYTOCHROME INTERACTING FACTOR 4 and PHYTOCHROME INTERACTING FACTOR 5 and stabilizes growth-repressing DELLA proteins, inhibiting auxin biosynthesis via a dual mechanism. Our findings show that UVR8 signaling is closely integrated with other photoreceptor pathways to regulate auxin signaling and plant growth in sunlight.

  17. UVB induces IL-12 transcription in human keratinocytes in vivo and in vitro

    International Nuclear Information System (INIS)

    Enk, C.D.; Blauvet, A.; Katz, S.I.; Mahanty, S.

    1996-01-01

    Human epidermal cells produce a wide range of cytokines, including those characteristic of Th2-like responses such as interleukin (IL)-4 and IL-10. As well, keratinocytes have recently been shown to produce Th1-like cytokines such as IL-12. Exposure to UVB has profound effects on the skin and systemic immune system, which is in part mediated by secretion of tumor necrosis factor (TNF)-α by epidermal cells. Because IL-12 induces production of TNF-α by certain cells of the immune system, we sought to determine whether UVB is an inducer of IL-12 gene expression in epidermal cells. Human epidermal cells were exposed to UVB radiation in vivo, isolated by suction blister technique and trypsinization and transcription of the IL-12 p35 and p40 chains was examined by RT-PCR. (Author)

  18. Phototherapy UVB narrow band treatment of psoriasis, mycosis fungoides and vitiligo

    International Nuclear Information System (INIS)

    Reyes, M.V.; Kutnizky, R.; Bosch, M.P.; Ruiz Lascano, A.

    2013-01-01

    Introduction: Numerous studies have shown the beneficial effect of ultraviolet radiation for the treatment of lymphoproliferative or inflammatory skin diseases. Objective: To determine the response to UVB narrow band (UVB-nb) in psoriasis, mycosis fungoides stage IA, IB and vitiligo, in the Dermatology Department of Hospital Privado from May 2009 to January 2011. To correlate total energy dose used and the total number of sessions with the response achieved in each disease. To describe adverse reactions; determine demographic characteristics of the population and comorbidities in psoriasis and vitiligo. Material and Methods: We performed a prospective, descriptive, analytical, observational study. We included all patients assessed for initiation of UVB-nb. Regarding the patients who did not start or interrupted the treatment a survey was conducted to assess the causes. We calculated the cumulative dose and number of sessions at the end of treatment. (authors) [es

  19. Pectins, ROS homeostasis and UV-B responses in plant roots.

    Science.gov (United States)

    Yokawa, Ken; Baluška, František

    2015-04-01

    Light from the sun contains far-red, visible and ultra violet (UV) wavelength regions. Almost all plant species have been evolved under the light environment. Interestingly, several photoreceptors, expressing both in shoots and roots, process the light information during the plant life cycle. Surprisingly, Arabidopsis root apices express besides the UVR8 UV-B receptor, also root-specific UV-B sensing proteins RUS1 and RUS2 linked to the polar cell-cell transport of auxin. In this mini-review, we focus on reactive oxygen species (ROS) signaling and possible roles of pectins internalized via endocytic vesicle recycling system in the root-specific UV-B perception and ROS homeostasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Centella asiatica protects against UVB-induced HaCaT keratinocyte damage through microRNA expression changes.

    Science.gov (United States)

    An, In-Sook; An, Sungkwan; Choe, Tae-Βoo; Kang, Sang-Μo; Lee, Jae Ho; Park, In-Chul; Jin, Young-Woo; Lee, Su-Jae; Bae, Seunghee

    2012-12-01

    This study aimed to evaluate the protective effects of Centella asiatica (C. asiatica) against ultraviolet B (UVB) damage in human keratinocytes using microRNA (miRNA) expression profiling analysis. Titrated extract of C. asiatica (TECA) demonstrated low cytotoxicity in normal human HaCaT keratinocytes only at low doses (<5 µg/ml). UVB (50 mJ/cm2) irradiation significantly decreased cell viability, and TECA treatment decreased the UVB toxicity. By using miRNA microarrays, we determined that 72 miRNAs had an altered expression following TECA treatment in UVB-irradiated keratinocytes (46 upregulated and 26 downregulated). Using an miRNA target gene prediction tool and Gene Ontology (GO) analysis, we determined that miRNAs with altered expression were functionally related with the inhibition of apoptosis and cell proliferation. Overall, these results provide meaningful information to facilitate the understanding of TECA-mediated UVB protection in human keratinocytes.

  1. Ultrathin gate valve for high vacuum operation

    Science.gov (United States)

    Ugiansky, R. J.

    1971-01-01

    Thin, compact, high-vacuum gate valve used to join two vacuum systems together demonstrates multiple operation reliability. Valve measurements and non-protruding handle make valve usable in confined areas.

  2. Gauge field vacuum structure in geometrical aspect

    International Nuclear Information System (INIS)

    Konopleva, N.P.

    2003-01-01

    Vacuum conception is one of the main conceptions of quantum field theory. Its meaning in classical field theory is also very profound. In this case the vacuum conception is closely connected with ideas of the space-time geometry. The global and local geometrical space-time conceptions lead to different vacuum definitions and therefore to different ways of physical theory construction. Some aspects of the gauge field vacuum structure are analyzed. It is shown that in the gauge field theory the vacuum Einstein equation solutions describe the relativistic vacuum as common vacuum of all gauge fields and its sources. Instantons (both usual and hyperbolical) are regarded as nongravitating matter, because they have zero energy-momentum tensors and correspond to vacuum Einstein equations

  3. Nanoscale Vacuum Electronics: Back to the Future?

    Data.gov (United States)

    National Aeronautics and Space Administration — This CIF project developed nanoscale vacuum devices for potential radiation-immune electronics ideal for space applications. Vacuum is superior to any semiconductor...

  4. A morphological and cytological study of Petunia hybrida exposed to UV-B radiation

    International Nuclear Information System (INIS)

    Staxén, I.; Bornmann, J.F.

    1994-01-01

    The aim of this study was to investigate whether the cytoskeleton, and in particular the microtubular system, is affected by enhanced levels of ultraviolet-B (280–320 nm, 9 kJ m −2 day −1 biologically effective UV-B radiation) radiation in epidermal cells of Petunia x hybrida Vilm, isolated from leaves of plants grown under UV-B radiation and visible light. In addition, morphological changes during development were monitored. In a previous study microtubules were depolymerized and delays in the different stages of the cell cycle were found when protoplasts of Petunia were irradiated with UV-B radiation (Staxén et al. 1993. Protoplasma 173: 70–76). Thus it was of interest to ascertain whether the cytoskeleton would be similarly affected in an intact system. Assuming an effect of UV-B radiation on the microtubular system, we wished to determine whether this could be correlated to concomitant changes in leaf morphology. Plants of Petunia hybrida were grown in greenhouse conditions in the presence or absence of UV-B radiation. During the course of the experiment, samples were taken from young, expanding leaves and from older, fully expanded leaves and prepared for localization and analysis of microtubules from the adaxial epidermal cells. Morphology rather than the cytoskeleton was affected by UV radiation, despite the fact that the epidermal cytoskeleton would most likely be affected, since it is located in the cells which form the first intercepting layer for incident radiation. Morphological changes under UV-B radiation, as compared to those under control conditions, were reflected in earlier flowering and an increase in leaf number. Cell division was thus stimulated as was also evidenced from the increased leaf area. Our results indicate that the number of stomata differentiated on a leaf area basis was not altered although the number of stomata per epidermal cell was reduced. (author)

  5. UV-B induction of NADP-malic enzyme in etiolated and green maize seedlings

    International Nuclear Information System (INIS)

    Drincovich, M.F.; Casati, P.; Andreo, C.S.; Donahue, R.; Edwards, G.E.

    1998-01-01

    The effect of treatment of etiolated maize seedlings with UV-B and UV-A radiation, and different levels of photosynthetically active radiation (PAR, 400–700 nm), on the activity and quantity of NADP-malic enzyme (NADPME) and on RNA levels was determined. Under low levels of PAR (14 µmol m –2 s –1 ), exposure to UV-B radiation (9 µmol m –2 s –1 ) but not UV-A radiation (11 µmol m –2 s –1 ) for 6–24 h caused a marked increase in the activity of the enzyme similar to that observed under high PAR (300 µmol m –2 s –1 ) in the absence of UV-B. Western blot analysis indicated there was a specific increase of the photosynthetically active isoform of the enzyme. This increase was also measured at the RNA level by dot blot analysis, indicating that the induction is displayed at the level of NADP-ME transcription. UV-B treatment of green leaves after a 12 h dark period also caused an increase in the activity and level of NADP-ME. The UV-B induction of NADP-ME synthesis may reflect a mechanism for induction of photosynthetic processes in C4 photosynthesis. Alternatively, the relatively low intensity of UV-B radiation present under full sunlight might provide a signal that facilitates repair of UV-B-induced damage through the increased activity of different enzymes such as NADP-ME. It is speculated that the reducing power and pyruvate generated by activity of NADP-ME may be used for respiration in cellular repair processes and as substrates for the fatty acid synthesis required for membrane repair. (author)

  6. Research on vacuum insulation for cryocables

    International Nuclear Information System (INIS)

    Graneau, P.

    1974-01-01

    Vacuum insulation, as compared with solid insulation, simplifies the construction of both resistive or superconducting cryogenic cables. The common vacuum space in the cable can furnish thermal insulation between the environment and the cryogenic coolant, provide electrical insulation between conductors, and establish thermal isolation between go- and return-coolant streams. The differences between solid and vacuum high voltage insulation are discussed, and research on the design, materials selection, and testing of vacuum insulated cryogenic cables is described

  7. Robot Vacuum Cleaner Personality and Behavior

    OpenAIRE

    Hendriks, A.F.M.; Meerbeek, B.W.; Boess, S.; Pauws, S.C; Sonneveld, M.

    2011-01-01

    In this paper we report our study on the user experience of robot vacuum cleaner behavior. How do people want to experience this new type of cleaning appliance? Interviews were conducted to elicit a desired robot vacuum cleaner personality. With this knowledge in mind, behavior was designed for a future robot vacuum cleaner. A video prototype was used to evaluate how people experienced the behavior of this robot vacuum cleaner. The results indicate that people recognizedthe intended personali...

  8. Solar UV-B radiation modulates chemical defenses against Anticarsia gemmatalis larvae in leaves of field-grown soybean.

    Science.gov (United States)

    Dillon, Francisco M; Chludil, Hugo D; Zavala, Jorge A

    2017-09-01

    Although it is well known that solar ultraviolet B (UV-B) radiation enhances plant defenses, there is less knowledge about traits that define insect resistance in field-grown soybean. Here we study the effects of solar UV-B radiation on: a) the induction of phenolic compounds and trypsin proteinase inhibitors (TPI) in soybean undamaged leaves or damaged by Anticarsia gemmatalis neonates during six days, and b) the survival and mass gain of A. gemmatalis larvae that fed on soybean foliage. Two soybean cultivars (cv.), Charata and Williams, were grown under plastic with different transmittance to solar UV-B radiation, which generated two treatments: ambient UV-B (UVB+) and reduced UV-B (UVB-) radiation. Solar UV-B radiation decreased survivorship by 30% and mass gain by 45% of larvae that fed on cv. Charata, but no effect was found in those larvae that fed on cv. Williams. TPI activity and malonyl genistin were induced by A. gemmatalis damage in both cultivars, but solar UV-B radiation and damage only synergistically increased the induction of these compounds in cv. Williams. Although TPI activity and genistein derivatives were induced by herbivory, these results did not explain the differences found in survivorship and mass gain of larvae that fed on cv. Charata. However, we found a positive association between lower larval performance and the presence of two quercetin triglycosides and a kaempferol triglycoside in foliage of cv. Charata, which were identified by HPLC-DAD/MS 2 . We conclude that exclusion of solar UV-B radiation reduce resistance to A. gemmatalis, due to a reduction in flavonol concentration in a cultivar that has low levels of genistein derivatives like cv. Charata. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Different levels of UV-B resistance in Vaccinium corymbosum cultivars reveal distinct backgrounds of phenylpropanoid metabolites.

    Science.gov (United States)

    Luengo Escobar, Ana; Magnum de Oliveira Silva, Franklin; Acevedo, Patricio; Nunes-Nesi, Adriano; Alberdi, Miren; Reyes-Díaz, Marjorie

    2017-09-01

    UV-B radiation induces several physiological and biochemical effects that can influence regulatory plant processes. Vaccinium corymbosum responds differently to UV-B radiation depending on the UV-B resistance of cultivars, according to their physiological and biochemical features. In this work, the effect of two levels of UV-B radiation during long-term exposure on the phenylpropanoid biosynthesis, and the expression of genes associated with flavonoid biosynthesis as well as the absolute quantification of secondary metabolites were studied in two contrasting UV-B-resistant cultivars (Legacy, resistant and Bluegold, sensitive). Multivariate analyses were performed to understand the role of phenylpropanoids in UV-B defense mechanisms. The amount of phenylpropanoid compounds was generally higher in Legacy than in Bluegold. Different expression levels of flavonoid biosynthetic genes for both cultivars were transiently induced, showing that even in longer period of UV-B exposure; plants are still adjusting their phenylpropanoids at the transcription levels. Multivariate analysis in Legacy indicated no significant correlation between gene expression and the levels of the flavonoids and phenolic acids. By contrast, in the Bluegold cultivar higher number of correlations between secondary metabolite and transcript levels was found. Taken together, the results indicated different adjustments between the cultivars for a successful UV-B acclimation. While the sensitive cultivar depends on metabolite adjustments to respond to UV-B exposure, the resistant cultivar also possesses an intrinsically higher antioxidant and UV-B screening capacity. Thus, we conclude that UV-B resistance involves not only metabolite level adjustments during the acclimation period, but also depends on the intrinsic metabolic status of the plant and metabolic features of the phenylpropanoid compounds. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  10. The protective roles of TiO2nanoparticles against UV-B toxicity in Daphnia magna.

    Science.gov (United States)

    Liu, Jie; Wang, Wen-Xiong

    2017-09-01

    Aquatic environments are increasingly under environmental stress due to ultraviolet (UV) radiation and potential inputs of nanoparticles with intense application of nanotechnology. In this study, we investigated the interaction between UV-B radiation and titanium nanoparticles (TiO 2 -NPs) in a model freshwater cladoceran Daphnia magna. UV-B toxicity to Daphnia magna was examined when the daphnids were exposed to a range of TiO 2 -NPs concentrations with an initial 5 or 10min of 200μW/cm 2 UV-B radiation. In addition, UV-B toxicity was also examined in the presence of TiO 2 -NPs in the body of daphnids. Our results demonstrated that the daphnid mortality under UV-B radiation decreased significantly in the presence of TiO 2 -NPs both in the water and in the body, indicating that TiO 2 -NPs had some protective effects on D. magna against UV-B. Such protective effect was mainly caused by the blockage of UV-B by TiO 2 -NPs adsorption. UV-B produced reactive oxygen species (ROS) in the water and in the daphnids, which was not sufficient to cause mortality of daphnids over short periods of radiation. Previous studies focused on the effects of TiO 2 -NPs on the toxicity of total UV radiation, and did not attempt to differentiate the potential diverse roles of UV-A and UV-B. Our study indicated that TiO 2 -NPs may conversely protect the UV-B toxicity to daphnids. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Determining the Location of DNA Modification and Mutation Caused by UVB Light in Skin Cancer

    Science.gov (United States)

    2015-09-01

    were being administered. To address this we obtained an LED bulb from Qphotonics that emits light at 315nm ± 10 nm (10) and incorporated it into a...Award Number: W81XWH-12-1-0333 TITLE: Determining the Location of DNA Modification and Mutation Caused by UVB Light in Skin Cancer PRINCIPAL...Caused by UVB Light in Skin Cancer 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Monica Ransom, PhD Betty Diamond 5d. PROJECT NUMBER

  12. UV-B affects photosynthesis, ROS production and motility of the freshwater flagellate, Euglena agilis Carter.

    Science.gov (United States)

    Kottuparambil, Sreejith; Shin, Woongghi; Brown, Murray T; Han, Taejun

    2012-10-15

    The effects of ultraviolet B (UV-B; 295-320 nm) radiation on certain vital physiological (photosynthesis), biochemical (production of reactive oxygen species - ROS) and behavioral (motility and orientation) characteristics were investigated in the unicellular photoautotroph, Euglena agilis Carter. The photosynthetic performance of E. agilis was recorded after exposure of between 15 and 60 min followed by a period of recovery lasting 6-24h under dim light (5-10 μmol photons m(-2) s(-1)). The maximum quantum yield of PS II (F(v)/F(m)) was reduced to 65% and 14% of initial values immediately following 15 and 30 min UV-B exposure, but recovered to 100 and 86% of the initials, respectively. Values of rETR(max) in E. agilis exposed to 15 min UV-B were similar to those of the initials, but a 30 min UV exposure resulted in 75% reduction of rETR(max) with only a 43% recovery as compared with the initial after 24h recovery. After a 60 min UV-B exposure, there were no Chl a fluorescence signals, and hence no F(v)/F(m) or rETR(max). A UV dose-dependent increase in DCFH-DA fluorescence was found in E. agilis cells, reflecting an increase in ROS production. After exposures to UV-B for between 15 and 60 min, the percentages of motile cells in the population decreased to 76, 39 and 15%, respectively. Following 24h in dim light, the percentage of motile cells increased to between 66% and 95% of the initial value. The velocity of non-irradiated cells was 60 μm s(-1), which decreased to 16-35 μm s(-1) immediately following exposure for 15-60 min. After periods of time in dim light (6, 12 and 24h) velocities had recovered to between 44 and 81% of the initial value. In untreated controls, the r-value was 0.23, indicating random movement of E. agilis, but it increased to 0.35 and 0.72 after exposure to UV-B for 30 and 60 min, respectively. There was a tendency towards vertical downward movement of cells proportional to the duration of exposure. The compactness of E. agilis decreased

  13. UV-B radiation modulates physiology and lipophilic metabolite profile in Olea europaea.

    Science.gov (United States)

    Celeste Dias, Maria; Pinto, Diana C G A; Correia, Carlos; Moutinho-Pereira, José; Oliveira, Helena; Freitas, Helena; Silva, Artur M S; Santos, Conceição

    2018-03-01

    Ultraviolet-B (UV-B) radiation plays an important role in plant photomorphogenesis. Whilst the morpho-functional disorders induced by excessive UV irradiation are well-known, it remains unclear how this irradiation modulates the metabolome, and which metabolic shifts improve plants' tolerance to UV-B. In this study, we use an important Mediterranean crop, Olea europaea, to decipher the impacts of enhanced UV-B radiation on the physiological performance and lipophilic metabolite profile. Young olive plants (cv. 'Galega Vulgar') were exposed for five days to UV-B biologically effective doses of 6.5 kJ m -2  d -1 and 12.4 kJ m -2 d -1 . Cell cycle/ploidy, photosynthesis and oxidative stress, as well as GC-MS metabolites were assessed. Both UV-B treatments impaired net CO 2 assimilation rate, transpiration rate, photosynthetic pigments, and RuBisCO activity, but 12.4 kJ m -2  d -1 also decreased the photochemical quenching (qP) and the effective efficiency of PSII (Φ PSII ). UV-B treatments promoted mono/triperpene pathways, while only 12.4 kJ m -2  d -1 increased fatty acids and alkanes, and decreased geranylgeranyl-diphosphate. The interplay between physiology and metabolomics suggests some innate ability of these plants to tolerate moderate UV-B doses (6.5 kJ m -2  d -1 ). Also their tolerance to higher doses (12.4 kJ m -2  d -1 ) relies on plants' metabolic adjustments, where the accumulation of specific compounds such as long-chain alkanes, palmitic acid, oleic acid and particularly oleamide (which is described for the first time in olive leaves) play an important protective role. This is the first study demonstrating photosynthetic changes and lipophilic metabolite adjustments in olive leaves under moderate and high UV-B doses. Copyright © 2018 Elsevier GmbH. All rights reserved.

  14. Wafer-Level Vacuum Packaging of Smart Sensors.

    Science.gov (United States)

    Hilton, Allan; Temple, Dorota S

    2016-10-31

    The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors-"low cost" for ubiquitous presence, and "smart" for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level vacuum packaging technology of smart sensors. We describe the processes needed to create the wafer-scale vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS) integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level vacuum packaging technology.

  15. Wafer-Level Vacuum Packaging of Smart Sensors

    Directory of Open Access Journals (Sweden)

    Allan Hilton

    2016-10-01

    Full Text Available The reach and impact of the Internet of Things will depend on the availability of low-cost, smart sensors—“low cost” for ubiquitous presence, and “smart” for connectivity and autonomy. By using wafer-level processes not only for the smart sensor fabrication and integration, but also for packaging, we can further greatly reduce the cost of sensor components and systems as well as further decrease their size and weight. This paper reviews the state-of-the-art in the wafer-level vacuum packaging technology of smart sensors. We describe the processes needed to create the wafer-scale vacuum microchambers, focusing on approaches that involve metal seals and that are compatible with the thermal budget of complementary metal-oxide semiconductor (CMOS integrated circuits. We review choices of seal materials and structures that are available to a device designer, and present techniques used for the fabrication of metal seals on device and window wafers. We also analyze the deposition and activation of thin film getters needed to maintain vacuum in the ultra-small chambers, and the wafer-to-wafer bonding processes that form the hermetic seal. We discuss inherent trade-offs and challenges of each seal material set and the corresponding bonding processes. Finally, we identify areas for further research that could help broaden implementations of the wafer-level vacuum packaging technology.

  16. 14 CFR 25.1433 - Vacuum systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vacuum systems. 25.1433 Section 25.1433... STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Miscellaneous Equipment § 25.1433 Vacuum systems. There... discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe. ...

  17. Utilize Vacuum Forming to Make Interdisciplinary Connections

    Science.gov (United States)

    Love, Tyler S.; Valenza, Frank

    2011-01-01

    The concept of vacuum forming has been around since the 19th century, despite not being fully utilized in industry until the 1950s. In the past, industrial arts classes have used vacuum-forming projects to concentrate solely on the manufacturing process and the final product. However, vacuum forming is not just an old industrial arts activity; it…

  18. 14 CFR 29.1433 - Vacuum systems.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Vacuum systems. 29.1433 Section 29.1433... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Equipment Miscellaneous Equipment § 29.1433 Vacuum systems. (a... the discharge lines from the vacuum air pump when the delivery temperature of the air becomes unsafe...

  19. A HIGH VACUUM GAUGE CALIBRATION SYSTEM

    Science.gov (United States)

    An ultra- high vacuum type metal and glass system was constructed for the purpose of calibrating vacuum gauges in the pressure region from 760 to 10...to the -7th power torr. The high vacuum portion of the system is bakeable at temperatures up to 450 C. A mercury manometer serves as a pressure

  20. 10 October 2013 - D. Braun First Deputy Minister for Regional Development, Czech Republic, P. Styczeń Deputy Minister of Transport, Construction and Maritime Economy, Republic of Poland and F. Palko State Secretary, Ministry of Transport, Construction and Regional Development, Slovak Republic visiting the LHC tunnel at Point 1 with Technology Department, Vacuum, Surfaces and Coatings Group Leader J. M. Jimenez and signing the Guest book with CERN Director-General R. Heuer

    CERN Multimedia

    Anna Pantelia

    2013-01-01

    10 October 2013 - D. Braun First Deputy Minister for Regional Development, Czech Republic, P. Styczeń Deputy Minister of Transport, Construction and Maritime Economy, Republic of Poland and F. Palko State Secretary, Ministry of Transport, Construction and Regional Development, Slovak Republic visiting the LHC tunnel at Point 1 with Technology Department, Vacuum, Surfaces and Coatings Group Leader J. M. Jimenez and signing the Guest book with CERN Director-General R. Heuer

  1. Plant Responses to Increased UV-B Radiation: A Research Project

    Science.gov (United States)

    DAntoni, H. L.; Skiles, J. W.; Armstrong, R.; Coughlan, J.; Daleo, G.; Mayoral, A.; Lawless, James G. (Technical Monitor)

    1994-01-01

    Ozone decrease implies more ultraviolet-B (UV-B) radiation reaching the surface of the Earth. Increased UV-B radiation triggers responses by living organisms. Despite the large potential impacts on vegetation, little is known about UV-B effects on terrestrial ecosystems. Long-term ecological studies are needed to quantify the effects of increased UV radiation on terrestrial ecosystems, asses the risks, and produce reliable data for prediction. Screening pigments are part of one of the protective mechanism in plants. Higher concentrations of screening pigments in leaves may be interpreted as a response to increased UV radiation. If the screening effect is not sufficient, important molecules will be disturbed by incoming radiation. Thus, genetics, photosynthesis, growth, plant and leaf shape and size, and pollen grains may be affected. This will have an impact on ecosystem dynamics, structure and productivity. It is necessary to monitor selected terrestrial ecosystems to permit detection and interpretation of changes attributable to global climate change and depleted ozone shield. The objectives of this project are: (1) To identify and measure indicators of the effects of increased solar UV-B radiation on terrestrial plants; (2) to select indicators with the greatest responses to UV-B exposure; (3) to test, adapt or create ecosystem models that use the information gathered by this project for prediction and to enhance our understanding of the effects of increased UV-B radiation on terrestrial ecosystems. As a first step to achieve these objectives we propose a three-year study of forest and steppe vegetation on the North slope of the Brooks Range (within the Arctic circle, in Alaska), in the Saguaro National Monument (near Tucson, Arizona) and in the forests and steppes of Patagonia (Argentina). We selected (1) vegetation north of the Polar Circle because at 70N there is 8% risk of plant damage due to increased UV-B radiation; (2) the foothills of Catalina Mountains

  2. DHU1 negatively regulates UV-B signaling via its direct interaction with COP1 and RUP1.

    Science.gov (United States)

    Kim, Sang-Hoon; Kim, Hani; Chung, Sunglan; Lee, Jae-Hoon

    2017-09-16

    Although DWD HYPERSENSITIVE TO UV-B 1 (DHU1) is reported to be a negative regulator in UV-B mediated cellular responses, its detailed role in UV-B signaling is still elusive. To further understand the action mechanism of DHU1 in UV-B response, physical and genetic interactions of DHU1 with various UV-B signaling components were investigated. Yeast two hybrid assay results suggested that DHU1 directly interacts with COP1 and RUP1, implying a functional connection with both COP1 and RUP1. In spite of the physical association between DHU1 and COP1, loss of DHU1 did not affect protein stability of COP1. Epistatic analysis showed that the functional loss of both DHU1 and UVR8 leads to alleviation of UV-B hypersensitivity displayed in dhu1-1. Moreover, phenotypic studies with dhu1-1 cop1-6 and dhu1-1 hy5-215 revealed that COP1 and HY5 are epistatic to DHU1, indicating that UV-B hypersensitivity of dhu1-1 requires both COP1 and HY5. In the case of dhu1-1 rup1-1, UV-B responsiveness was similar to that of both dhu1-1 and rup1-1, implying that DHU1 and RUP1 are required for each other's function. Collectively, these results show that the role of DHU1 as a negative regulator in UV-B response may be derived from its direct interaction with COP1 by sequestering COP1 from the active UVR8-COP1 complex, resulting in a decrease in the COP1 population that positively participates in UV-B signaling together with UVR8. Furthermore, this inhibitory role of DHU1 in UV-B signaling is likely to be functionally connected to RUP1. This study will serve as a platform to further understand more detailed action mechanism of DHU1 in UV-B response and DHU1-mediated core UV-B signaling in Arabidopsis. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Quantum vacuum and dark matter

    CERN Document Server

    Hajdukovic, Dragan Slavkov

    2012-01-01

    Recently, the gravitational polarization of the quantum vacuum was proposed as alternative to the dark matter paradigm. In the present paper we consider four benchmark measurements: the universality of the central surface density of galaxy dark matter haloes, the cored dark matter haloes in dwarf spheroidal galaxies, the non-existence of dark disks in spiral galaxies and distribution of dark matter after collision of clusters of galaxies (the Bullet cluster is a famous example). Only some of these phenomena (but not all of them) can (in principle) be explained by the dark matter and the theories of modified gravity. However, we argue that the framework of the gravitational polarization of the quantum vacuum allows the understanding of the totality of these phenomena.

  4. LEP vacuum chamber, early prototype

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The structure of LEP, with long bending magnets and little access to the vacuum chamber between them, required distributed pumping. This is an early prototype for the LEP vacuum chamber, made from extruded aluminium. The main opening is for the beam. The small channel to the right is for cooling water, to carry away the heat deposited by the synchroton radiation from the beam. The 4 slots in the channel to the left house the strip-shaped ion-getter pumps (see 7810255). The ion-getter pumps depended on the magnetic field of the bending magnets, too low at injection energy for the pumps to function well. Also, a different design was required outside the bending magnets. This design was therefore abandoned, in favour of a thermal getter pump (see 8301153 and 8305170).

  5. "Flat-Fish" Vacuum Chamber

    CERN Multimedia

    CERN PhotoLab

    1978-01-01

    The picture shows a "Flat-Fish" vacuum chamber being prepared in the ISR workshop for testing prior to installation in the Split Field Magnet (SFM) at intersection I4. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of thin stainless steel sheets to the Split Field Magnet poles in order to take the vertical component of the atmospheric pressure force. This was the thinnest vacuum chamber ever made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature. In this picture the thin sheets transferring the vertical component of the atmosferic pressure force are attached to a support frame for testing. See also 7712182, 7712179.

  6. Vacuum mammotomy under ultrasound guidance

    International Nuclear Information System (INIS)

    Luczynska, E.; Kocurek, A.; Pawlik, T.; Aniol, J.; Herman, K.; Skotnicki, P.

    2007-01-01

    Breast ultrasound is a non-invasive method of breast examination. You can use it also for fine needle biopsy, core needle biopsy, vacuum mammotomy and for placing the '' wire '' before open surgical biopsy. 106 patients (105 women and 1 man) aged 20-71 years (mean age 46.9) were treated in Cancer Institute in Cracow by vacuum mammotomy under ultrasound guidance. The lesions found in ultrasonography were divided into three groups: benign lesions (BI RADS II), ambiguous lesions (BI RADS 0, III and IVa), and suspicious lesions (BI RADS IV B, IV C and V). Then lesions were qualified to vacuum mammotomy. According to USG, fibroadenoma or '' fibroadenoma-like '' lesions were found in 75 women, in 6 women complicated cysts, in 6 women cyst with dense fluid (to differentiate with FA), and in 19 patients undefined lesions. Fibroadenoma was confirmed in histopathology in 74% patients among patients with fibroadenoma or '' fibroadenoma-like '' lesions in ultrasound (in others also benign lesions were found). Among lesions undefined after ultrasound examination (total 27 patients) cancer was confirmed in 6 % (DCIS and IDC). In 6 patients with complicated cysts in ultrasound examination, histopathology confirmed fibroadenoma in 4 women, an intraductal lesion in 1 woman and inflamatory process in 1 woman. Also in 6 women with a dense cyst or fibroadenoma seen in ultrasound, histopathology confirmed fibroadenoma in 3 women and fibrosclerosis in 3 women. Any breast lesions undefined or suspicious after ultrasound examination should be verified. The method of verification or kind of operation of the whole lesion (vacuum mammotomy or '' wire '') depends on many factors, for example: lesion localization; lesion size; BI RADS category. (author)

  7. Field Emission in Vacuum Microelectronics

    CERN Document Server

    Fursey, George; Schwoebel, Paul

    2005-01-01

    Field emission is a phenomenon described by quantum mechanics. Its emission capability is millions times higher than that of any other known types of electron emission. Nowadays this phenomenon is experiencing a new life due to wonderful applications in the atomic resolution microscopy, in electronic holography, and in the vacuum micro- and nanoelectronics in general. The main field emission properties, and some most remarkable experimental facts and applications, are described in this book.

  8. Vacuum evaporation of pure metals

    OpenAIRE

    Safarian, Jafar; Engh, Thorvald Abel

    2013-01-01

    Theories on the evaporation of pure substances are reviewed and applied to study vacuum evaporation of pure metals. It is shown that there is good agreement between different theories for weak evaporation, whereas there are differences under intensive evaporation conditions. For weak evaporation, the evaporation coefficient in Hertz-Knudsen equation is 1.66. Vapor velocity as a function of the pressure is calculated applying several theories. If a condensing surface is less than one collision...

  9. Entanglement in the Bogoliubov vacuum

    DEFF Research Database (Denmark)

    Poulsen, Uffe Vestergaard; Meyer, T.; Lewenstein, M.

    2005-01-01

    We analyze the entanglement properties of the Bogoliubov vacuum, which is obtained as a second-order approximation to the ground state of an interacting Bose-Einstein condensate. We work in one- and two-dimensional lattices and study the entanglement between two groups of sites as a function...... and to be favoured by strong interactions. Conversely, long-range entanglement is favoured by relatively weak interactions. No examples of bound entanglement are found....

  10. Random numbers from vacuum fluctuations

    International Nuclear Information System (INIS)

    Shi, Yicheng; Kurtsiefer, Christian; Chng, Brenda

    2016-01-01

    We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.

  11. Vacuum electronics applications at CERN

    CERN Document Server

    Jensen, E

    2009-01-01

    CERN operates a large number of vacuum electronics based RF power amplifiers covering a wide frequency range – over 300 sockets with 24 different grid tubes and klystrons are in use and require constant care to insure reliable operation of the accelerators. This is in particular true for the LHC and its injector chain, for which a program of improvement and stepwise upgrade has started. These include IOT’s for the SPS and klystrons and modulators for Linac4 and SPL. The CLIC study and the CTF3 facility are relevant to vacuum electronics in many ways: The CLIC primary RF power, to be provided at 1 GHz, requires highest possible efficiency and phase stability, MBK’s are likely candidates. The CLIC RF power source and CTF3 are themselves large vacuum electronics applications, consequently there are areas of common interest and concern, including fabrication techniques, pulse compression techniques, breakdown and multipactor theory and simulation, material fatigue, numerical analysis of slow-wave structures...

  12. PC driven integrated vacuum system

    International Nuclear Information System (INIS)

    Curuia, Marian; Culcer, Mihai; Brandea, Iulian; Anghel, Mihai

    2001-01-01

    The monitoring of industrial plants by virtual instrumentation represents the most modern trend in the domain of electronic equipment. The integrated vacuum system presented here has several facilities, including the automated data storing of measurement results on hard disk and providing warning messages for operators when the measured parameters are lower or higher upper than the fixed values. The system can also work stand-alone, receiving the commands from the keyboards placed on his front panel but, when it is included in a automation complex system, a remote control from PC is necessary . Both parts of the system, power supply unit for turbo-molecular pump and the vacuum gage, are controlled by an 80C31 microcontroller. Because this microcontroller has a built-in circuitry for a serial communication, we established a serial communication between the PC and the power supply unit for turbo-molecular pump and the vacuum gage, according to the RS-232 hardware standard. As software, after careful evaluation of several options, we chose to develop a hybrid software packing using two different software development tools: LabVIEW, and assembly language. We chose LabVIEW because it is dedicated to data acquisition and communications, containing libraries for data collection, analysis, display and storage. (authors)

  13. Kinetics of scrap tyre pyrolysis under vacuum conditions.

    Science.gov (United States)

    Lopez, Gartzen; Aguado, Roberto; Olazar, Martín; Arabiourrutia, Miriam; Bilbao, Javier

    2009-10-01

    Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies the kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12K in the reaction starting temperature. The kinetic constant at 503K for devolatilization of volatile additives at 0.25atm is 1.7 times higher than that at 1atm, and that corresponding to styrene-butadiene rubber at 723K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate.

  14. Kinetics of scrap tyre pyrolysis under vacuum conditions

    International Nuclear Information System (INIS)

    Lopez, Gartzen; Aguado, Roberto; Olazar, Martin; Arabiourrutia, Miriam; Bilbao, Javier

    2009-01-01

    Scrap tyre pyrolysis under vacuum is attractive because it allows easier product condensation and control of composition (gas, liquid and solid). With the aim of determining the effect of vacuum on the pyrolysis kinetics, a study has been carried out in thermobalance. Two data analysis methods have been used in the kinetic study: (i) the treatment of experimental data of weight loss and (ii) the deconvolution of DTG (differential thermogravimetry) curve. The former allows for distinguishing the pyrolysis of the three main components (volatile components, natural rubber and styrene-butadiene rubber) according to three successive steps. The latter method identifies the kinetics for the pyrolysis of individual components by means of DTG curve deconvolution. The effect of vacuum in the process is significant. The values of activation energy for the pyrolysis of individual components of easier devolatilization (volatiles and NR) are lower for pyrolysis under vacuum with a reduction of 12 K in the reaction starting temperature. The kinetic constant at 503 K for devolatilization of volatile additives at 0.25 atm is 1.7 times higher than that at 1 atm, and that corresponding to styrene-butadiene rubber at 723 K is 2.8 times higher. Vacuum enhances the volatilization and internal diffusion of products in the pyrolysis process, which contributes to attenuating the secondary reactions of the repolymerization and carbonization of these products on the surface of the char (carbon black). The higher quality of carbon black is interesting for process viability. The large-scale implementation of this process in continuous mode requires a comparison to be made between the economic advantages of using a vacuum and the energy costs, which will be lower when the technologies used for pyrolysis require a lower ratio between reactor volume and scrap tyre flow rate.

  15. Rotary bayonets for cryogenic and vacuum service

    International Nuclear Information System (INIS)

    Rucinski, R.A.; Dixon, K.D.; Krasa, R.; Krempetz, K.J.; Mulholland, G.T.; Trotter, G.R.; Urbin, J.B.

    1993-07-01

    Rotary bayonets were designed, tested, and installed for liquid nitrogen, liquid argon, and vacuum service. This paper will present the design, testing, and service record for two sizes of vacuum jacketed cryogenic rotary bayonets and two sizes of vacuum service rotary bayonets. Materials used in construction provide electrical isolation across the bayonet joint. The joint permits 360 degrees of rotation between the male and female pipe sections while maintaining integrity of service. Assemblies using three such joints were built to allow end connection points to be translated through at least 1 meter of horizontal travel while kept in service. Vacuum jacketed sizes built in-house at Fermi National Accelerator Laboratory are 1-1/2 in. inner pipe size, 3 in. vacuum jacket, and 4 in. inner pipe size, 6 in. vacuum jacket The single wall vacuum service bayonets are in 4 in. and 6 in. pipe sizes. The bayonets have successfully been in active service for over one year

  16. Biochemical traits and proteomic changes in postharvest flowers of medicinal chrysanthemum exposed to enhanced UV-B radiation.

    Science.gov (United States)

    Yao, Xiaoqin; Chu, Jian-Zhou; Ma, Chun-Hui; Si, Chao; Li, Ji-Gang; Shi, Xiao-Fei; Liu, Chao-Nan

    2015-08-01

    The article studied UV-B effects on biochemical traits and proteomic changes in postharvest flowers of medicinal chrysanthemum. The experiment about UV-B effects on biochemical traits in flowers included six levels of UV-B treatments (0 (UV0), 50 (UV50), 200 (UV200), 400 (UV400), 600 (UV600) and 800 (UV800) μWcm(-2)). UV400, UV600 and UV800 treatments significantly increased the contents of hydrogen peroxide, malondialdehyde and UV-B absorbing compounds, and the activity of phenylalanine ammonia lyase enzyme over the control. The contents of chlorogenic acid and flavone in flowers were significantly increased by UV-B treatments (except for UV50 and UV800). Two-dimensional gel electrophoresis was utilized to analyze proteomic changes in flowers with or without UV-B radiation. Results indicated that 43 protein spots (>1.5-fold difference in volume) were detected, including 19 spots with a decreasing trend and 24 spots with an increasing trend, and 19 differentially expressed protein spots were successfully indentified by MALDI-TOF MS. The indentified proteins were classified based on functions, the most of which were involved in photosynthesis, respiration, protein biosynthesis and degradation and defence. An overall assessment using biochemical and differential proteomic data revealed that UV-B radiation could affect biochemical reaction and promote secondary metabolism processes in postharvest flowers. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Variations in UV-B tolerance and germination speed of Metarhizium anisopliae conidia produced on insects and artificial substrates.

    Science.gov (United States)

    Rangel, Drauzio E N; Braga, Gilberto U L; Flint, Stephan D; Anderson, Anne J; Roberts, Donald W

    2004-01-01

    Solar ultraviolet radiation (UV-A and UV-B) is a major factor in failure of programs using the insect pathogenic fungus Metarhizium anisopliae as a biological control agent. Studies were conducted to determine if growth conditions, viz. artificial (agar media or rice grain) or natural (infected insects) substrates for conidial production affect two traits that directly influence performance of conidia after field application: tolerance to UV-B radiation and conidial germination speed. Conidia of two isolates (ARSEF 23 and ARSEF 2575) of M. anisopliae var. anisopliae produced on potato dextrose agar plus yeast extract (PDAY) or on fungus-killed larvae of two insect species, Galleria mellonella and Zophobas morio, were inactivated by exposure to UV-B radiation. Conidia of both isolates when produced on insect cadavers were significantly more sensitive to UV-B radiation than conidia produced on PDAY. Also, conidia from insect cadavers germinated slower than those from PDAY cultures. A comparison of conidia from artificial substrates showed that conidia produced on Czapek's and Emerson's YpSs agar media or rice grains had higher tolerance to UV-B radiation and germinated faster than conidia raised on PDA and PDAY. Accordingly, the growth substrate and nutritional environment in which conidia are produced influences M. anisopliae conidial UV-B tolerance and speed of germination; and manipulation of these variables could be used to obtain conidia with increased tolerance to UV-B radiation and shorter germination times.

  18. Effect of Thai banana (Musa AA group) in reducing accumulation of oxidation end products in UVB-irradiated mouse skin.

    Science.gov (United States)

    Leerach, Nontaphat; Yakaew, Swanya; Phimnuan, Preeyawass; Soimee, Wichuda; Nakyai, Wongnapa; Luangbudnark, Witoo; Viyoch, Jarupa

    2017-03-01

    Chronic UVB exposure causes skin disorders and cancer through DNA strand breaks and oxidation of numerous functional groups of proteins and lipids in the skin. In this study, we investigated the effects of Thai banana (Musa AA group, "Khai," and Musa ABB group, "Namwa") on the prevention of UVB-induced skin damage when fed to male ICR mice. Mice were orally fed banana (Khai or Namwa) fruit pulps at dose of 1mg/g body weight/day for 12weeks. The shaved backs of the mice were irradiated with UVB for 12weeks. The intensity dose of UVB-exposure was increased from 54mJ/cm 2 /exposure at week 1 to 126mJ/cm 2 /exposure at week 12. A significant increase in skin thickness, lipid peroxidation, protein oxidation end products, and expression of MMP-1 was observed in UVB-irradiated mouse skin. A reduction in the accumulation of oxidation end products was found in the skin of UVB-irradiated mice receiving Khai. This occurred in conjunction with a reduction in MMP-1 expression, inhibition of epidermal thickening, and induction of γ-GCS expression. The dietary intake of Khai prevented skin damage from chronic UVB exposure by increased γ-GCS expression and reduced oxidation end products included carbonyls, malondialdehyde and 4-hydroxynonenal. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Angiotensin-converting enzyme inhibitor (enalapril maleate) accelerates recovery of mouse skin from UVB-induced wrinkles

    Energy Technology Data Exchange (ETDEWEB)

    Matsuura-Hachiya, Yuko; Arai, Koji Y.; Ozeki, Rieko; Kikuta, Ayako; Nishiyama, Toshio, E-mail: toshio_n@cc.tuat.ac.jp

    2013-12-06

    Highlights: •Angiotensin converting enzyme (ACE) increases in UVB-irradiated skin. •Administration of an ACE inhibitor improved UVB-induced skin wrinkle. •ACE inhibitor improved UVB-induced epidermal hypertrophy. •ACE inhibitor improved transepidermal water loss in the UVB-irradiated skin. -- Abstract: Angiotensin-converting enzyme (ACE) activity and angiotensin II signaling regulate cell proliferation, differentiation, and tissue remodeling, as well as blood pressure, while in skin, angiotensin II signaling is involved in wound healing, inflammation, and pathological scar formation. Therefore, we hypothesized that angiotensin II is also involved in photoaging of skin. In this study, we examined the effect of enalapril maleate, an ACE inhibitor, on recovery of wrinkled skin of hairless mice exposed to long-term UVB irradiation. Immunohistochemical observation revealed that expression of ACE, angiotensin II, and angiotensin II type 1 (AT1) and type 2 (AT2) receptors in the skin was increased after UVB irradiation (3 times/week at increasing intensities for 8 weeks). Administration of enalapril maleate (5 times/week for 6 weeks, starting 1 week after 10-week irradiation) accelerated recovery from UVB-induced wrinkles, epidermal hyperplasia and epidermal barrier dysfunction, as compared with the vehicle control. Our results indicate that ACE and angiotensin II activity are involved in skin photoaging, and suggest that ACE inhibitor such as enalapril maleate may have potential for improvement of photoaged skin.

  20. Silver nanoparticles protect human keratinocytes against UVB radiation-induced DNA damage and apoptosis: potential for prevention of skin carcinogenesis

    Science.gov (United States)

    Arora, Sumit; Tyagi, Nikhil; Bhardwaj, Arun; Rusu, Lilia; Palanki, Rohan; Vig, Komal; Singh, Shree R.; Singh, Ajay P.; Palanki, Srinivas; Miller, Michael E.; Carter, James E.; Singh, Seema

    2015-01-01

    Ultraviolet (UV)-B radiation from the sun is an established etiological cause of skin cancer, which afflicts more than a million lives each year in the United States alone. Here, we tested the chemopreventive efficacy of silver-nanoparticles (AgNPs) against UVB-irradiation-induced DNA damage and apoptosis in human immortalized keratinocytes (HaCaT). AgNPs were synthesized by reduction-chemistry and characterized for their physicochemical properties. AgNPs were well tolerated by HaCaT cells and their pretreatment protected them from UVB-irradiation-induced apoptosis along with significant reduction in cyclobutane-pyrimidine-dimer formation. Moreover, AgNPs pre-treatment led to G1-phase cell-cycle arrest in UVB-irradiated HaCaT cells. AgNPs were efficiently internalized in UVB-irradiated cells and localized into cytoplasmic and nuclear compartments. Furthermore, we observed an altered expression of various genes involved in cell-cycle, apoptosis and nucleotide-excision repair in HaCaT cells treated with AgNPs prior to UVB-irradiation. Together, these findings provide support for potential utility of AgNPs as novel chemopreventive agents against UVB-irradiation-induced skin carcinogenesis. PMID:25804413

  1. Observation and analysis on skin cancer induced by UVB irradiation using optical coherence tomography

    Science.gov (United States)

    Wang, Yunxia; Wu, Shulian; Li, Hui; Zheng, Xiaoxiao

    2014-09-01

    Basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) are the prevalent skin cancers, which have a quite high incidence in the white race. In recent years, however, their incidences have been increasing in the yellow race, resulting in a great threat to the public health. According to researches, chronics UVB irradiation (280nm~320nm) is the major culprit of skin cancer in humans. In our study, the model of UVB induced skin cancer was established firstly. Optical coherence tomography (OCT) combined with the histopathology was exploited to monitor the morphologic and histological changes of the process of UVB induced skin cancer. Meanwhile, this canceration process was systematically studied and analyzed from the perspective of tissue optics. The attenuation coefficient (μt) has a rising trend in the epidermis, but which shows a downward trend in the dermis. The results are conducive to understand the process of UVB-induced skin cancer and further be able to provide a reference for medical researchers.

  2. Inhibitory mechanism of Korean Red Ginseng on GM-CSF expression in UVB-irradiated keratinocytes

    Directory of Open Access Journals (Sweden)

    Ira Chung

    2015-10-01

    Conclusion: Taken together, we found that treatment with SKRG decreased the phosphorylation of EGFR and ERK in UVB-irradiated SP-1 keratinocytes and subsequently inhibited the expression of GM-CSF. Furthermore, we identified ginsenoside-Rh3 as the active saponin in Korean Red Ginseng.

  3. Passiflora tarminiana fruits reduce UVB-induced photoaging in human skin fibroblasts.

    Science.gov (United States)

    Bravo, Karent; Duque, Luisa; Ferreres, Federico; Moreno, Diego A; Osorio, Edison

    2017-03-01

    Skin aging is a complex process that is strongly affected by UV radiation, which stimulates the production of reactive oxygen species (ROS) in the epidermis and dermis and subsequently causes skin damage. Among the major consequences are increased collagen degradation and reduced collagen synthesis. Previous reports have demonstrated the beneficial effects of polyphenols for healthy skin. Passiflora tarminiana Coppens & V.E. Barney, a species of the Passifloraceae family, is widely distributed in South America and is rich in flavonoids. We show that UVB radiation increases metalloproteinase 1 (MMP-1) and reduces procollagen production in human dermal fibroblast (HDF) cells in a dose- and time-dependent manner. We examined the antioxidant and antiaging effects of the extract and fractions of P. tarminiana fruits. The fractions showed high polyphenol content (620mg EAG/g) and antioxidant activity, as measured by ORAC (4097μmol ET/g) and ABTS (2992μmol ET/g) assays. The aqueous fraction drastically inhibited the collagenase enzyme (IC 50 0.43μg/mL). The extract and fractions presented photoprotective effects by reducing UVB-induced MMP-1 production, increasing UVB-inhibited procollagen production, and decreasing ROS production after UVB irradiation in HDF. Finally, the polyphenol contents of the extracts and fractions from P. tarminiana were analyzed by HPLC-DAD-ESI-MS n , and procyanidins and glycosylated flavonoids were identified. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Effect of biflavones of Ginkgo biloba against UVB-induced cytotoxicity in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong-Jin [Chonnam National Univ., Kwangju (Korea, Republic of). Medical School

    2001-04-01

    The effect of Ginkgo biloba extract on Ultraviolet B (UVB) irradiated fibroblasts was examined by using a neutral red dye uptake assay and a lactic dehydrogenase (LDH) release assay. Crude extract along with individual components, including flavone-glycosides and biflavones, were applied to cultured normal human skin fibroblasts for 12 hours, and 0, 20, 40 and 80 mJ/cm{sup 2} of UVB were irradiated. Two synthetic flavonoids, quercetin and rutin, which have polyphenol structures close to the flavonoids in Ginkgo biloba extract, were used to compare any structure-related activity under the same conditions. At the concentrations (from 0.25 to 2 mg/ml) treated with biflavone components (isoginkgetin/ginkgetin, sciadopitysin) and quercetin, high neutral red dye uptake was detected with gradual increases in UVB irradiation. The time-course release of LDH was determined as the cytotoxicity index (%) during 24 hours following a high dose UVB irradiation (200 mJ/cm{sup 2}), and the pattern of this cytotoxicity index was similar to that of the neutral red dye uptake results. Sciadopitysin, isoginkgetin/ginkgetin and quercetin treatments lowered cytotoxicity indices to 50.81, 67.81 and 62.19%, respectively, compared to 95.38% for the untreated control. The antioxidant potential of biflavones of Ginkgo biloba could be explained on the basis of structure-related activity; hydroxy- and methyl-substitutions on the basic structure of these flavonoids played a role, as other reports have suggested. (author)

  5. Differential flavonoid response to enhanced UV-B radiation in Brassica napus

    International Nuclear Information System (INIS)

    Olsson, L.C.; Veit, M.; Weissenböck, G.; Bornman, J.F.

    1998-01-01

    We have examined the qualitative and quantitative differences in methanol-soluble flavonoids of leaves of two cultivars of Brassica napus, which were grown with or without (control) supplemental UV-B radiation. The flavonoids were identified using HPLC-diode array spectroscopy (-DAS), -electrospray ionization-mass spectroscopy (-ESI-MS) and 1H and 13C NMR, and quantitatively analysed by HPLC-DAS. After exposure to supplementary UV-B radiation, the overall amount of soluble flavonoids, kaempferol and quercetin glycosides, increased by ca 150% in cv. Paroll, compared to control plants. Cultivar Stallion showed a 70% increase, and also a lower overall content of soluble flavonoids compared to Paroll. The supplementary UV-B radiation resulted in a marked, specific increase in the amount of quercetin glycosides relative to the kaempferol glycosides with a 36- and 23-fold increase in cvs Paroll and Stallion, respectively. Four of the flavonol glycosides appearing after supplemental UV-B exposure were identified as quercetin- and kaempferol 3-sophoroside-7-glucoside and 3-(2″′-E-sinapoylsophoroside)-7-glucoside. (author)

  6. Sensitivity of two ecotypes of Arabidopsis Thaliana (Cvi and Te) towards UV-B irradiation

    International Nuclear Information System (INIS)

    Velichkova, M.; Stanoeva, D.; Popova, A.

    2013-01-01

    he susceptibility of Arabidopsis thaliana towards the detrimental effect of UV-B irradiation was investigated using two ecotypes, Cvi and Te. The effect of UV-B treatment on primary photosynthetic reactions - energy interaction between the main pigment-protein complexes and oxygen evolution, was evaluated at low (4 0 C) and at room (22 0 C) temperature. UV-B-induced alterations of investigated photosynthetic reactions are better expressed at 22 0 C than at 4 0 C for Cvi. For Te ecotype the energy interaction was suppressed to higher extent at 22 0 C, while oxygen evolving activity was affected similarly at both temperatures. At low and room temperature, the energy interaction in the complex PSII-core antenna is affected stronger by UV-B treatment than the energy distribution between both photosystems, as revealed by fluorescence ratios of 77 K spectra. The results presented indicate that the Arabidopsis thaliana ecotype Cvi (Cape Verde Islands) is less affected by UV-B irradiation in respect to the investigated primary photosynthetic reactions than the ecotype Te (Finland)

  7. Ambient UV-B radiation decreases photosynthesis in high arctic Vaccinium uliginosum

    DEFF Research Database (Denmark)

    Albert, Kristian Rost; Mikkelsen, Teis Nørgaard; Ro-Poulsen, H.

    2008-01-01

    An UV-B-exclusion experiment was established in high arctic Zackenberg, Northeast Greenland, to investigate the possible effects of ambient UV-B on plant performance. During almost a whole growing season, canopy gas exchange and Chl fluorescence were measured on Vaccinium uliginosum (bog blueberry...

  8. UVB 311 nm tolerance of vitiligo skin increases with skin photo type

    NARCIS (Netherlands)

    Caron-Schreinemachers, Anne-Lou D. B.; Kingswijk, Melanie M.; Bos, Jan D.; Westerhof, Wiete

    2005-01-01

    It is assumed that skin is protected against sunburn by melanin. In patients with vitiligo, there are white patches in the normal pigmented skin. We noticed that there is a difference in burning capacity of these white patches between people with different skin types. With UVB 311 nm lamps, we

  9. Elevated level of polysaccharides in a high level UV-B tolerant cell ...

    African Journals Online (AJOL)

    Jane

    2011-04-26

    Apr 26, 2011 ... Key words: Bupleurum scorzonerifolium Willd, polysaccharides, in vitro culture, UV-B tolerance, antioxidant. ..... The number of calli formed from protoplasts of the anti-UV-B cell line after different generation of subculture. Figure 4. ..... Tanaka A, Sakamoto A, Ishigaki Y, Nikaido O, Sun G, Hase Y, Shikazono.

  10. Effects of ultraviolet-B (UV-B) radiation on two cryptogamic plants ...

    African Journals Online (AJOL)

    rudra

    Two plant species, lichen (X. elegans) and moss (B. argenteum) were selected and both were growing naturally on the mountains with other cryptogamic vegetation (Figure 2a and b). We have selected these plants for the field experiments because of their uniform growth, availability and UV-B filter frames can be placed.

  11. Quantitation of pyrimidine dimers in DNA from UVB-irradiated alfalfa (Medicago sativa L.) seedlings

    International Nuclear Information System (INIS)

    Quaite, F.E.; Sutherland, B.M.; Sutherland, J.C.

    1991-01-01

    Depletion of stratospheric ozone will increase the solar ultraviolet radiation in the range from 290-320 nm (UVB) that reaches the surface of the earth, placing an increased UV burden on exposed organisms. One consequence of increased UVB may be decreased productivity of crop plants. A principal lesion caused by UV in DNA is the cyclobutyl pyrimidine dimer. We have adapted a method for measuring these dimers in nanogram quantities of non-radioactive DNA for use in UV-irradiated plants. We find that biologically relevant doses of broad band UVB radiation induce easily detectable frequencies of pyrimidine dimers in the DNA of irradiated alfalfa sprout leaves and that the dose response for dimer formation is linear up to doses of at least 690 J/m 2 . We also find easily measurable frequencies of dimers in the leaves of seedlings grown in glass filtered sunlight but not exposed to additional UVB, suggesting that significant number of dimers are formed in plants exposed to normal sunlight. 27 refs., 3 figs., 1 tab

  12. Probing behaviors of Sitobion avenae (Hemiptera: Aphididae on enhanced UV-B irradiated plants

    Directory of Open Access Journals (Sweden)

    Hu Zu-Qing

    2013-01-01

    Full Text Available UV-B induced changes in plants can influence sap-feeding insects through mechanisms that have not been studied. Herein the grain aphid, Sitobion avenae (Fabricius (Hemiptera: Aphididae, was monitored on barley plants under the treatments of control [0 kJ/ (m2.d], ambient UV-B [60 kJ/ (m2.d], and enhanced UV-B [120 kJ/ (m2.d] irradiation. Electrical penetration graph (EPG techniques were used to record aphid probing behaviors. Enhanced UV-B irradiated plants negatively affected probing behaviors of S. avenae compared with control plants. In particular, phloem factors that could diminish sieve element acceptance appeared to be involved, as reflected by smaller number of phloem phase, shorter phloem ingestion, and fewer aphids reaching the sustained phloem ingestion phase (E2>10min. On the other hand, factors from leaf surface, epidermis, and mesophyll cannot be excluded, as reflected by higher number of non-probing, longer non-probing and pathway phase, and later the time to first probe.

  13. Influence of low ozone episodes on erythemal UV-B radiation in Austria

    Science.gov (United States)

    Schwarz, Matthias; Baumgartner, Dietmar J.; Pietsch, Helga; Blumthaler, Mario; Weihs, Philipp; Rieder, Harald E.

    2017-06-01

    This study investigates the influence of low ozone episodes on UV-B radiation in Austria during the period 1999 to 2015. To this aim observations of total column ozone (TCO) in the Greater Alpine Region (Arosa, Switzerland; Hohenpeissenberg, Germany; Hradec Kralove, Czech Republic; Sonnblick, Austria), and erythemal UV-B radiation, available from 12 sites of the Austrian UV-B monitoring network, are analyzed. As previous definitions for low ozone episodes are not particularly suited to investigate effects on UV radiation, a novel threshold approach—considering anomalies—is developed to provide a joint framework for the analysis of extremes. TCO and UV extremes are negatively correlated, although modulating effects of sunshine duration impact the robustness of the statistical relationship. Therefore, information on relative sunshine duration (SDrel), available at (or nearby) UV-B monitoring sites, is included as explanatory variable in the analysis. The joint analysis of anomalies of both UV index (UVI) and total ozone (∆UVI, ∆TCO) and SDrel across sites shows that more than 65% of observations with strongly negative ozone anomalies (∆TCO 1), we find (across all sites) that about 90% correspond to negative ∆TCO. The remaining 10% of days occurred during fair weather conditions (SDrel ≥ 80%) explaining the appearance of ∆UVI > 1 despite positive TCO anomalies. Further, we introduce an anomaly amplification factor (AAF), which quantifies the expected change of the ∆UVI for a given change in ∆TCO.

  14. Protective effect of different antioxidant agents in UVB-irradiated keratinocytes

    Directory of Open Access Journals (Sweden)

    Sara Salucci

    2017-09-01

    Full Text Available Skin cells can respond to UVB-induced damage either by tolerating it, or restoring it through antioxidant activation and DNA repair mechanisms or, ultimately, undergoing programmed cell death, when damage is massive. Nutritional factors, in particular, food antioxidants, have attracted much interest because of their potential use in new preventive, protective, and therapeutic strategies for chronic degenerative diseases, including skin inflammation and cancer. Some polyphenols, present in virgin olive oil, well tolerated by organism after oral administration, show a variety of pharmacological and clinical benefits such as anti-oxidant, anti-cancer, anti-inflammatory, and neuro-protective activities. Here, the protective effects of antioxidant compounds against UV-induced apoptosis have been described in HaCat cell line. Human keratinocytes were pre-treated with antioxidants before UVB exposure and their effects have been evaluated by means of ultrastructural analyses. After UVB radiation, a known cell death trigger, typical apoptotic features, absent in control condition and in antioxidant alone-treated cells, appear. An evident numerical decrease of ultrastructural apoptotic patterns and TUNEL positive nuclei can be observed when natural antioxidants were supplied before cell death induction. These data have been confirmed by molecular investigation of caspase activity. In conclusion, this paper highlights antioxidant compound ability to prevent apoptotic cell death in human keratinocytes exposed to UVB, suggesting, for these molecules, a potential role in preventing skin damage. 

  15. Time Spent per delta PASI (TSdP) among psoriasis patients undergoing UVB-therapy

    DEFF Research Database (Denmark)

    Ring, Hans Christian; Vinding, Gabrielle Randskov; Miller, Iben Marie

    2015-01-01

    BACKGROUND: Psoriasis often poses a significant challenge to treat. Ultraviolet light band (UVB) treatment is widely used and well recognized. However, the frequent visits to the dermatologist may indirectly present an impediment to many of the patients' careers and every day life due to the vast...

  16. Antagonist Effects of Veratric Acid against UVB-Induced Cell Damages

    Directory of Open Access Journals (Sweden)

    Deokhoon Park

    2013-05-01

    Full Text Available Ultraviolet (UV radiation induces DNA damage, oxidative stress, and inflammatory processes in human epidermis, resulting in inflammation, photoaging, and photocarcinogenesis. Adequate protection of skin against the harmful effect of UV irradiation is essential. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. The simple phenolic veratric acid (VA, 3,4-dimethoxybenzoic acid is one of the major benzoic acid derivatives from vegetables and fruits and it also occurs naturally in medicinal mushrooms which have been reported to have anti-inflammatory and anti-oxidant activities. However, it has rarely been applied in skin care. This study, therefore, aimed to explore the possible roles of veratric acid in protection against UVB-induced damage in HaCaT cells. Results showed that veratric acid can attenuate cyclobutane pyrimidine dimers (CPDs formation, glutathione (GSH depletion and apoptosis induced by UVB. Furthermore, veratric acid had inhibitory effects on the UVB-induced release of the inflammatory mediators such as IL-6 and prostaglandin-E2. We also confirmed the safety and clinical efficacy of veratric acid on human skin. Overall, results demonstrated significant benefits of veratric acid on the protection of keratinocyte against UVB-induced injuries and suggested its potential use in skin photoprotection.

  17. Antagonist effects of veratric acid against UVB-induced cell damages.

    Science.gov (United States)

    Shin, Seoung Woo; Jung, Eunsun; Kim, Seungbeom; Lee, Kyung-Eun; Youm, Jong-Kyung; Park, Deokhoon

    2013-05-10

    Ultraviolet (UV) radiation induces DNA damage, oxidative stress, and inflammatory processes in human epidermis, resulting in inflammation, photoaging, and photocarcinogenesis. Adequate protection of skin against the harmful effect of UV irradiation is essential. In recent years naturally occurring herbal compounds such as phenolic acids, flavonoids, and high molecular weight polyphenols have gained considerable attention as beneficial protective agents. The simple phenolic veratric acid (VA, 3,4-dimethoxybenzoic acid) is one of the major benzoic acid derivatives from vegetables and fruits and it also occurs naturally in medicinal mushrooms which have been reported to have anti-inflammatory and anti-oxidant activities. However, it has rarely been applied in skin care. This study, therefore, aimed to explore the possible roles of veratric acid in protection against UVB-induced damage in HaCaT cells. Results showed that veratric acid can attenuate cyclobutane pyrimidine dimers (CPDs) formation, glutathione (GSH) depletion and apoptosis induced by UVB. Furthermore, veratric acid had inhibitory effects on the UVB-induced release of the inflammatory mediators such as IL-6 and prostaglandin-E2. We also confirmed the safety and clinical efficacy of veratric acid on human skin. Overall, results demonstrated significant benefits of veratric acid on the protection of keratinocyte against UVB-induced injuries and suggested its potential use in skin photoprotection.

  18. Effects of prolonged UV-B exposure in plants | Mpoloka | African ...

    African Journals Online (AJOL)

    High levels of UV-B radiation are responsible for multiple biologically harmful effects in both plants and animals. In plants, these effects include DNA damage, which often causes heritable mutations affecting various physiological processes, including the photosynthetic apparatus, protein destruction and signal transduction ...

  19. Changes in aqueous humor following single or repeated UVB irradiation of rabbit cornea

    Czech Academy of Sciences Publication Activity Database

    Fris, M.; Čejková, Jitka; Midelfart, A.

    2007-01-01

    Roč. 245, č. 11 (2007), s. 1705-1711 ISSN 0721-832X R&D Projects: GA ČR GA304/06/1379 Institutional research plan: CEZ:AV0Z50390512 Keywords : Aqueous humour * Nuclear magnetic resonance * UVB rays Subject RIV: FF - HEENT, Dentistry Impact factor: 1.590, year: 2007

  20. Involvement of MIF in basement membrane damage in chronically UVB-exposed skin in mice.

    Directory of Open Access Journals (Sweden)

    Yoko Yoshihisa

    Full Text Available Solar ultraviolet (UV B radiation is known to induce matrix metalloproteinases (MMPs that degrade collagen in the basement membrane. Macrophage migration inhibitory factor (MIF is a pluripotent cytokine that plays an essential role in the pathophysiology of skin inflammation induced by UV irradiation. This study examined the effects of MIF on basement membrane damage following chronic UVB irradiation in mice. The back skin of MIF transgenic (Tg and wild-type (WT mice was exposed to UVB three times a week for 10 weeks. There was a decrease in intact protein levels of type IV collagen and increased basement membrane damage in the exposed skin of the MIF Tg mice compared to that observed in the WT mice. Moreover, the skin of the MIF Tg mice exhibited higher MIF, MMP-2 and MMP-9 expression and protein levels than those observed in the WT mice. We also found that chronic UVB exposure in MIF Tg mice resulted in higher levels of neutrophil infiltration in the dermis compared with that observed in the WT mice. In vitro experiments revealed that MIF induced increases in the MMPs expression, including that of MMP-9 in keratinocytes and MMP-2 in fibroblasts. Cultured neutrophils also secreted MMP-9 stimulated by MIF. Therefore, MIF-mediated basement membrane damage occurs primarily through MMPs activation and neutrophil influx in murine skin following chronic UVB irradiation.

  1. UV-B Radiation Impacts Shoot Tissue Pigment Composition in Allium fistulosum L. Cultigens

    Science.gov (United States)

    Abney, Kristin R.; Kopsell, Dean A.; Sams, Carl E.; Zivanovic, Svetlana; Kopsell, David E.

    2013-01-01

    Plants from the Allium genus are valued worldwide for culinary flavor and medicinal attributes. In this study, 16 cultigens of bunching onion (Allium fistulosum L.) were grown in a glasshouse under filtered UV radiation (control) or supplemental UV-B radiation [7.0 μmol·m−2 ·s−2 (2.68 W·m−2)] to determine impacts on growth, physiological parameters, and nutritional quality. Supplemental UV-B radiation influenced shoot tissue carotenoid concentrations in some, but not all, of the bunching onions. Xanthophyll carotenoid pigments lutein and β-carotene and chlorophylls a and b in shoot tissues differed between UV-B radiation treatments and among cultigens. Cultigen “Pesoenyj” responded to supplemental UV-B radiation with increases in the ratio of zeaxanthin + antheraxanthin to zeaxanthin + antheraxanthin + violaxanthin, which may indicate a flux in the xanthophyll carotenoids towards deepoxydation, commonly found under high irradiance stress. Increases in carotenoid concentrations would be expected to increase crop nutritional values. PMID:23606817

  2. UV-B impact on aphid performance mediated by plant quality and plant changes induced by aphids.

    Science.gov (United States)

    Kuhlmann, F; Müller, C

    2010-07-01

    Plants face various abiotic and biotic environmental factors and therefore need to adjust their phenotypic traits on several levels. UV-B radiation is believed to impact herbivorous insects via host plant changes. Plant responses to abiotic challenges (UV-B radiation) and their interaction with two aphid species were explored in a multifactor approach. Broccoli plants [Brassica oleracea L. convar. botrytis (L.), Brassicaceae] were grown in two differently covered greenhouses, transmitting either 80% (high UV-B) or 4% (low UV-B) of ambient UV-B. Three-week-old plants were infested with either specialist cabbage aphids [Brevicoryne brassicae (L.), Sternorrhyncha, Aphididae] or generalist green peach aphids [Myzus persicae (Sulzer), Sternorrhyncha, Aphididae]. Plants grown under high-UV-B intensities were smaller and had higher flavonoid concentrations. Furthermore, these plants had reduced cuticular wax coverage, whereas amino acid concentrations of the phloem sap were little influenced by different UV-B intensities. Cabbage aphids reproduced less on plants grown under high UV-B than on plants grown under low UV-B, whereas reproduction of green peach aphids in both plant light sources was equally poor. These results are likely related to the different specialisation-dependent sensitivities of the two species. The aphids also affected plant chemistry. High numbers of cabbage aphid progeny on low-UV-B plants led to decreased indolyl glucosinolate concentrations. The induced change in these glucosinolates may depend on an infestation threshold. UV-B radiation considerably impacts plant traits and subsequently affects specialist phloem-feeding aphids, whereas aphid growth forces broccoli to generate specific defence responses.

  3. The imprints of the high light and UV-B stresses in Oryza sativa L. 'Kanchana' seedlings are differentially modulated.

    Science.gov (United States)

    Faseela, Parammal; Puthur, Jos T

    2018-01-01

    High light and ultraviolet-B radiation (UV-B) are generally considered to have negative impact on photosynthesis and plant growth. The present study evaluates the tolerance potential of three cultivars of Oryza sativa L. (Kanchana, Mattatriveni and Harsha) seedlings towards high light and UV-B stress on the basis of photosynthetic pigment degradation, chlorophyll a fluorescence parameters and rate of lipid peroxidation, expressed by malondialdehyde content. Surprisingly, it was revealed that Kanchana was the most sensitive cultivar towards high light and at the same time it was the most tolerant cultivar towards UV-B stress. This contrasting feature of Kanchana towards high light and UV-B tolerance was further studied by analyzing photosystem (PS) I and II activity, mitochondrial activity, chlorophyll a fluorescence transient, enzymatic and non-enzymatic antioxidant defense system. Due to the occurrence of more PS I and PSII damages, the inhibition of photochemical efficiency and emission of dissipated energy as heat or fluorescence per PSII reaction center was higher upon high light exposure than UV-B treatments in rice seedlings of Kanchana. The mitochondrial activity was also found to be drastically altered upon high light as compared to UV-B treatments. The UV-B induced accumulation of non-enzymatic antioxidants (proline, total phenolics, sugar and ascorbate) and enzymatic antioxidants (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and glutathione reductase) in rice seedlings than those subjected to high light exposure afforded more efficient protection against UV-B radiation in rice seedlings. Our results proved that high tolerance of Kanchana towards UV-B than high light treatments, correlated linearly with the protected photosynthetic and mitochondrial machinery which was provided by upregulation of antioxidants particularly by total phenolics, ascorbate and ascorbate peroxidase in rice seedlings. Data presented in this study conclusively

  4. Direct effects of elevated UV-B radiation on the decomposition of Quercus robur leaf litter

    International Nuclear Information System (INIS)

    Newsham, K.K.; McLeod, A.R.; Roberts, J.D.; Greenslade, P.D.; Emmett, B.A.

    1997-01-01

    Decomposing Quercus robur L. leaf litter was exposed for 64 weeks at an outdoor facility to supplemental levels of UV-B radiation (280-315 nm) under treatment arrays of cellulose diacetate-filtered fluorescent lamps which also produce UV-A radiation (315-400 nm). Litter was also exposed to UV-A radiation alone under control arrays of polyester-filtered lamps and to ambient levels of solar radiation under arrays of unenergised lamps. The treatment corresponded to a 30% elevation above the ambient erythemally-weighted level of UV-B radiation. Litter was sampled after 11, 39 and 64 weeks and was examined for differences in mass loss, decomposition constants (k), chemical composition and the abundances of saprotrophic fungi. No effects of UV radiation on k values were recorded, but after 11 weeks, percentage mass loss of litter exposed to UV-B radiation under treatment arrays was 3% lower than under control arrays and 2% lower than under ambient arrays. After 39 weeks, litters exposed to UV-A radiation under control arrays had 10% lower total nitrogen contents and 13% higher C:N ratios than those litters exposed beneath ambient arrays. At the last sampling, litters exposed to supplemental UV-B radiation had 5% higher carbon contents than those under ambient arrays. A 2.4-fold increase in the frequency of lamina particles of litter that were uncolonised by fungi was recorded in litter exposed to UV-B radiation under treatment arrays, compared to ambient arrays. The abundances of the saprotrophic fungi Cladosporium spp. and Acremonium persicinum (Nicot) W. Gams were decreased by 50% and 91%, respectively, under UV-B treatment arrays compared to ambient arrays, and the abundance of coelomycete conidiomata recorded on leaves was increased by 12% under treatment arrays, compared to ambient. Dactylella spp. were not recorded on litter exposed to UV-A radiation under control arrays and UV-A radiation applied under control and treatment arrays apparently increased the

  5. Separate and combined responses to water deficit and UV-B radiation.

    Science.gov (United States)

    Bandurska, Hanna; Niedziela, Justyna; Chadzinikolau, Tamara

    2013-12-01

    Crops and other plants in natural conditions are routinely affected by several stresses acting simultaneously or in sequence. In areas affected by drought, plants may also be exposed to enhanced UV-B radiation (280-315nm). Each of these stress factors differently affects cellular metabolism. A common consequence of plant exposure to the separate action of water deficit and UV-B radiation is the enhanced generation of reactive oxygen species (ROS) causing damage to proteins, lipids, carbohydrates and DNA. Despite this destructive activity, ROS also act as signalling molecules in cellular processes responsible for defence responses. Plants have evolved many physiological and biochemical mechanisms that avoid or tolerate the effects of stress factors. Water deficit avoidance leads to stomatal closure, stimulation of root growth, and accumulation of free proline and other osmolytes. Secondary metabolites (flavonols, flavones and anthocyanins) that accumulate in epidermal cells effectively screen UV-B irradiation and reduce its penetration to mesophyll tissue. The coordinated increased activity of the enzymatic antioxidant defence system such as up-regulation of superoxide dismutase, catalase, guaiacol peroxidase, ascorbate peroxidase and glutathione reductase is an important mechanism of tolerance to water deficit and UV-B radiation. The accumulation of low molecular antioxidants (proline, glycine betaine, ascorbate and glutathione) can also contribute to tolerance to water deficit. Polyamines, tocopherol, carotenoids, alkaloids, flavonoids and other secondary metabolites participate in the removal of ROS under conditions of increased UV-B radiation. The combination of water deficit and UV-B radiation induces responses that can be antagonistic, additive or synergistic in comparison with the action of single stresses. UV-B radiation may enhance resistance to water deficit and vice versa. Hydrogen peroxide, nitric oxide (NO), abscisic acid (ABA), jasmonic acid, ethylene

  6. UV-B affects photosynthesis, ROS production and motility of the freshwater flagellate, Euglena agilis Carter

    International Nuclear Information System (INIS)

    Kottuparambil, Sreejith; Shin, Woongghi; Brown, Murray T.; Han, Taejun

    2012-01-01

    Highlights: ► We proposed a hypothesis for the UV-B protective/adaptive mechanism in Euglena agilis. After moderate levels of UV-B radiation, ROS plays a signaling role to shut down photosynthetic system for protection against harmful UV radiation. ► E. agilis exposed to excessive UV appears to become animal-like, investing all its stored energy into movement rather than into sustaining its photosynthetic machinery. ► This adaptation allows E. agilis to avoid harmful UV and seek a safe place where the organism may regain its photosynthetic capacity for survival. - Abstract: The effects of ultraviolet B (UV-B; 295–320 nm) radiation on certain vital physiological (photosynthesis), biochemical (production of reactive oxygen species – ROS) and behavioral (motility and orientation) characteristics were investigated in the unicellular photoautotroph, Euglena agilis Carter. The photosynthetic performance of E. agilis was recorded after exposure of between 15 and 60 min followed by a period of recovery lasting 6–24 h under dim light (5–10 μmol photons m −2 s −1 ). The maximum quantum yield of PS II (F v /F m ) was reduced to 65% and 14% of initial values immediately following 15 and 30 min UV-B exposure, but recovered to 100 and 86% of the initials, respectively. Values of rETR max in E. agilis exposed to 15 min UV-B were similar to those of the initials, but a 30 min UV exposure resulted in 75% reduction of rETR max with only a 43% recovery as compared with the initial after 24 h recovery. After a 60 min UV-B exposure, there were no Chl a fluorescence signals, and hence no F v /F m or rETR max . A UV dose-dependent increase in DCFH-DA fluorescence was found in E. agilis cells, reflecting an increase in ROS production. After exposures to UV-B for between 15 and 60 min, the percentages of motile cells in the population decreased to 76, 39 and 15%, respectively. Following 24 h in dim light, the percentage of motile cells increased to between 66% and 95% of

  7. [Effects of silicon supply on diurnal variations of physiological properties at rice heading stage under elevated UV-B radiation].

    Science.gov (United States)

    Wu, Lei; Lou, Yun-sheng; Meng, Yan; Wang, Wei-qing; Cui, He-yang

    2015-01-01

    A pot experiment was conducted to investigate the effects of silicon (Si) supply on diurnal variations of photosynthesis and transpiration-related physiological parameters at rice heading stage under elevated UV-B radiation. The experiment was designed with two UV-B radiation levels, i.e. ambient UV-B. (ambient, A) and elevated UV-B (elevated by 20%, E), and four Si supply levels, i.e. Sio (control, 0 kg SiO2 . hm-2), Si, (sodium silicate, 100 kg SiO2 . hm-2), Si2 (sodium silicate, 200 kg SiO2 . hm2), Si3 (slag fertilizer, 200 kg SiO2 . hm-2). The results showed that, compared with ambient UV-B radiation, elevated UV-B radiation decreased the net photosynthesis rate (Pn) , intercellular CO2 concentration (Ci), transpiration rate (Tr), stomatal conductivity (gs) and water use efficiency (WUE) by 11.3%, 5.5%, 10.4%, 20.3% and 6.3%, respectively, in the treatment without Si supply (Si, level), and decreased the above parameters by 3.8%-5.5%, 0.7%-4.8%, 4.0%-8.7%, 7.4%-20.2% and 0.7%-5.9% in the treatments with Si supply (Si1, Si2 and Si3 levels) , respectively. Namely, elevated UV-B radiation decreased the photosynthesis and transpiration-related physiological parameters, but silicon supply could obviously mitigate the depressive effects of elevated UV-B radiation. Under elevated UV-B radiation, compared with control (Si0 level), silicon supply increased Pn, Ci, gs and WUE by 16.9%-28.0%, 3.5%-14.3%, 16.8% - 38.7% and 29.0% - 51.2%, respectively, but decreased Tr by 1.9% - 10.8% in the treatments with Si supply (Si1 , Si2 and Si3 levels). That is, silicon supply could mitigate the depressive effects of elevated UV-B radiation through significantly increasingnP., CigsgK and WUE, but decreasing T,. However, the difference existed in ameliorating the depressive effects of elevated UV-B radiation on diurnal variations of physiological parameters among the treatments of silicon supply, with the sequence of Si3>Si2>1i >Si0. This study suggested that fertilizing slag was

  8. The influence of urban area opacity on biologically active UV-B irradiance

    Science.gov (United States)

    Chubarova, Nataly; Rozental', Victor

    2013-04-01

    The study of UV irradiance changes in urban area is an essential problem due to the significant effect of UV irradiance on human health which can be positive (vitamin D synthesis) and negative (erythema, skin cancer, eye damage). According to the results of several experiments within the Moscow megacity we studied the effects of urban area opacity on the different types of biologically active UV-B irradiance on the base of a specially developed mobile photometric complex snd additional measurements of the urban opacity by Nikon Fisheye Converter FC-E8. We analyzed both the level of erythemally-active irradiance and the UV eye damaging radiation using the broadband UVB-1 YES pyranometer calibrated against ultraviolet spectroradiometer Bentham DTM-300 of the Medical University of Innsbruck (courtesy of Dr. M.Blumthaler). In order to estimate the effects of the urban opacity the measurements were normalized on similar measurements at the Meteorological Observatory of Moscow State University with zero opacity. This ratio is defined as an urban radiative transmittance (URT). Different atmospheric conditions were considered. In cloudy conditions the effect of opacity on URT is much less than that in conditions when the sun disk is open from clouds. We revealed some spectral features in transmittance of biologically active UV-B irradiance which is characterized by higher URT variations in overcast cloudy conditions due to more intensive scattering and smaller direct solar radiation component. In the absence of cloudiness the effect of opacity was studied for open and screening solar disk conditions. We obtained much higher URT in UVB spectral region compared with that for total solar irradiance for screening solar disk conditions with a significant URT dependence on the opacity only in UVB spectral region. No URT dependence was obtained for total solar irradiance in these conditions. Some model calculations were fulfilled to match the experimental results.

  9. Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa (P. aeruginosa) biofilm

    Science.gov (United States)

    Argyraki, A.; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, P. M.

    2016-04-01

    Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

  10. Transcriptome responses involved in artemisinin production in Artemisia annua L. under UV-B radiation.

    Science.gov (United States)

    Pan, Wei Song; Zheng, Li Ping; Tian, Hao; Li, Wan Yi; Wang, Jian Wen

    2014-11-01

    Artemisinin, an endoperoxide sesquiterpene lactone, is an effective antimalarial drug isolated from Artemisia annua L. In this study, a low dose (1.44 kJm(-2)d(-1)) of UV-B radiation (280-320 nm) for short-term (1h per day for 10 days) was applied to A. annua seedlings to stimulate artemisinin production. UV-B treatment not only induced the generation of reactive oxygen species (ROS), enhanced peroxidase activity and endogenous content of abscisic acid (ABA), but stimulated the biosynthesis of artemisinin in the seedlings. Here, transcriptomic changes during UV-B radiation in A. annua were detected using an Agilent GeneChip with 43,692 probe sets. In total, 358 transcripts were identified as differentially expressed under UV-B stress, of which 172 transcripts increased and 186 transcripts decreased in abundance. In terms of biological processes, gene ontology (GO) terms including primary carbohydrate and nitrogen compound metabolic processes were enriched in UV-B-repressed genes. The up-regulated genes were enriched in response to stress, ROS generation, hormone (ethylene, ABA) stimulus and cell cycle control. The expression of key enzymes such as amorpha-4,11-diene synthase (ADS) and cytochrome P450 dependent monooxygenase/hydroxylase (CYP71AV1), and related WRKY transcription factors was up-regulated significantly for artemisinin biosynthesis. This profile of global gene expression patterns during UV-B stress will be valuable for further identification of the enzymes involved in artemisinin biosynthesis. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Photoprotection of Buddleja cordata extract against UVB-induced skin damage in SKH-1 hairless mice.

    Science.gov (United States)

    Avila Acevedo, José Guillermo; Espinosa González, Adriana Montserrat; De Maria y Campos, Diana Matamoros; Benitez Flores, José del Carmen; Hernández Delgado, Tzasna; Flores Maya, Saul; Campos Contreras, Jorge; Muñoz López, José Luis; García Bores, Ana María

    2014-08-03

    In recent years, there has been considerable interest in using botanical agents to prevent skin damage resulting from solar UV-irradiation. Buddleja cordata is a plant that is known as "tepozan". Some people in Mexico use the leaves of this plant to treat tumours, abscesses, sores and burns. The purpose of this study is to investigate the photoprotective properties of Buddleja cordata methanolic extract (BCME) against UVB-induced skin damage in SKH-1 hairless mice at the macroscopic and histological levels. BCME was characterised to determine its spectroscopic, chromatographic and antioxidant (DPPH, superoxide and hydroxyl radicals) properties. To conduct the photoprotection studies, BCME was applied topically to the skin of SKH-1 mice before acute exposure to UVB for 10 minutes. The murine skin samples were used for macroscopic and histological studies to assess tissue damage. Penetration of active components of BCME into stratum corneum on the dorsal area of mice was investigated in vivo by the tape stripping method. Moreover, genotoxicity of BCME was evaluated in a Vicia faba cell root micronucleus model. BCME displayed absorbance over the entire UVB spectrum, and its principal components included verbascoside and linarin. BCME exhibited antioxidant activity and significantly scavenged hydroxyl radicals. BCME reduced erythema, sunburn cell production, vessel congestion and epidermal thickening of UVB irradiated mouse skin. BCME penetrate the skin of mice. BCME did not exhibit genotoxic activity in the micronucleus test. The topical administration of BCME protected against acute UVB-induced damage in mouse SKH-1 skin, and our results suggest that BCME may potentially prevent photodamage.

  12. 1,8-cineole prevents UVB-induced skin carcinogenesis by targeting the aryl hydrocarbon receptor

    Science.gov (United States)

    Park, Joon; Kim, Yong Ho; Lee, Nam Hyouck; Kim, Young Eon; Kim, Yoonsook; Song, Kyung-Mo; Jung, Sung Keun

    2017-01-01

    1,8-cineole is a natural monoterpene cyclic ether present in Eucalyptus, and has been reported to exhibit anti-inflammatory and antioxidant effects. However, the preventive effect of 1,8-cineole on skin carcinogenesis and the molecular mechanism of action responsible remains unknown. In the present study, we investigated the effect of 1,8-cineole on UVB-induced skin carcinogenesis. 1,8-cineole inhibited UVB-induced cyclooxygenase-2 (COX-2) protein and mRNA expression and prostaglandin E2 (PGE2) generation in HaCaT cells. 1,8-cineole also inhibited phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, and phosphorylation of its upstream kinases, c-Src and epidermal growth factor receptor (EGFR). Quantitative real-time RT-PCR (qRT-PCR) and drug affinity responsive target stability (DARTS) assay results showed that 1,8-cineole suppressed UVB-induced expression of a target gene of the aryl hydrocarbon receptor (AhR), cyp1a1, and directly binds to AhR. Knockdown of AhR suppressed COX-2 expression as well as phosphorylation of ERK1/2 in HaCaT cells. Furthermore, topical treatment of 1,8-cineole on mouse skin delayed tumor incidence and reduced tumor numbers, while inhibiting COX-2 expression in vivo. Taken together, these results suggest that 1,8-cineole is a potent chemopreventive agent that inhibits UVB-induced COX-2 expression by targeting AhR to suppress UVB-induced skin carcinogenesis. PMID:29285309

  13. Narrowband UVB emitting (LaGd)B3O6:Bi3+ phosphor for phototherapy

    International Nuclear Information System (INIS)

    Bhatkar, N.V.; Thakare, D.S.; Bhatkar, V.B.

    2011-01-01

    Ultraviolet radiation (UVR) phototherapy is useful for treating more than 40 types of skin diseases and disorders, such as psoriasis, vitiligo, atopic dermatitis, morphea, scleroderma, cutaneous T-cell lymphoma, etc. Action spectrum studies have shown that the peak therapeutic activity is between 295 - 310 nm. A recent advance in phototherapy of psoriasis has been the introduction of narrowband UVB using a fluorescence irradiation device delivering virtually monochromatic light at 311 nm. Combining narrowband UVB with calcipotriol, a vitamin D 3 analogue, is considered a very effective treatment for psoriasis. Narrowband UVB is a useful therapy for the treatment of Vitiligo. Research into the influence of wavelength on therapeutic efficacy in phototherapy, confirmed that narrowband UVB is more effective and probably has no greater risk than conventional wideband UVB phototherapy in the treatment of skin disease. In addition, it was recognized that this would be an opportunity for better control and evaluation of treatment, faster and easier treatment time and potentially improved clearance. Lanthanum metaborate (LaGd)B 3 O 6 :Bi 3+ is a well- known commercial narrowband emitting phosphor used in phototherapy lamps for the treatment of psoriasis. The phosphor was prepared by a novel method which is a variation of the solution combustion synthesis. Heat generated in the exothermic reaction between ammonium nitrate and urea is used to carry out the synthesis. The XRD pattern of the prepared phosphor matches with the standard ICDD data. The PL emission of the prepared phosphor shows a narrowband emission spectrum centered around 310 nm in good agreement with the literature. (author)

  14. The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

    Directory of Open Access Journals (Sweden)

    O. Fridman

    2006-03-01

    Full Text Available The exposure of Bufo arenarum embryos to 300-310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m2 was the NOEC value for short-term chronic (10 days exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A, 820(B, 1368(C and 1915(D Joule/m2 at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure.

  15. Vacuum/gas handling systems for ZTH

    International Nuclear Information System (INIS)

    Downing, J.N.

    1987-01-01

    The proposed ZTH vacuum system consists of three (potentially four or more) high-vacuum-pumping-stations (HVPSs), a gas handling system, a roughing system, and a vacuum control system. Each high vacuum line consists of a turbomolecular pump (TMP) pumping stack connected to the torus through a right-angle valve, a duct, and a 2 kV insulating break/bellows combination. The HVPSs are designed to be bakeable to at least 150 C. The gate seals on the high-vacuum valves are vision O-rings. Throughout the vacuum liner and high-vacuum pumping system, metal sealed joints are used where possible. Any O-ring seals, other than the gate seals, are a double-pumped configuration where a roughing vacuum is maintained between the O-rings. The insulating break eliminates ground loop currents, and the bellows mechanically decouples the pumping from the vacuum liner. This bellows section will accommodate the dimensional changes caused by heating the liner and/or the high-vacuum system

  16. Running vacuum cosmological models: linear scalar perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Perico, E.L.D. [Instituto de Física, Universidade de São Paulo, Rua do Matão 1371, CEP 05508-090, São Paulo, SP (Brazil); Tamayo, D.A., E-mail: elduartep@usp.br, E-mail: tamayo@if.usp.br [Departamento de Astronomia, Universidade de São Paulo, Rua do Matão 1226, CEP 05508-900, São Paulo, SP (Brazil)

    2017-08-01

    In cosmology, phenomenologically motivated expressions for running vacuum are commonly parameterized as linear functions typically denoted by Λ( H {sup 2}) or Λ( R ). Such models assume an equation of state for the vacuum given by P-bar {sub Λ} = - ρ-bar {sub Λ}, relating its background pressure P-bar {sub Λ} with its mean energy density ρ-bar {sub Λ} ≡ Λ/8π G . This equation of state suggests that the vacuum dynamics is due to an interaction with the matter content of the universe. Most of the approaches studying the observational impact of these models only consider the interaction between the vacuum and the transient dominant matter component of the universe. We extend such models by assuming that the running vacuum is the sum of independent contributions, namely ρ-bar {sub Λ} = Σ {sub i} ρ-bar {sub Λ} {sub i} . Each Λ i vacuum component is associated and interacting with one of the i matter components in both the background and perturbation levels. We derive the evolution equations for the linear scalar vacuum and matter perturbations in those two scenarios, and identify the running vacuum imprints on the cosmic microwave background anisotropies as well as on the matter power spectrum. In the Λ( H {sup 2}) scenario the vacuum is coupled with every matter component, whereas the Λ( R ) description only leads to a coupling between vacuum and non-relativistic matter, producing different effects on the matter power spectrum.

  17. Technology.

    Science.gov (United States)

    Online-Offline, 1998

    1998-01-01

    Focuses on technology, on advances in such areas as aeronautics, electronics, physics, the space sciences, as well as computers and the attendant progress in medicine, robotics, and artificial intelligence. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books,…

  18. Development of a novel rf waveguide vacuum valve

    CERN Document Server

    Grudiev, A

    2006-01-01

    The development of a novel rf waveguide vacuum valve is presented. The rf design is based on the use of TE0n modes of circular waveguides. In the device, the TE01 mode at the input is converted into a mixture of several TE0n modes which provide low-loss rf power transmission across the vacuum valve gap, these modes are then converted back into the TE01 mode at the output. There are a number of advantages associated with the absence of surface fields in the region of the valve: • Possibility to use commercially available vacuum valves equipped with two specially designed mode converter sections. • No necessity for an rf contact between these two sections. • Increased potential for high power rf transmission. This technology can be used for all frequencies for which vacuum waveguides are used. In rectangular waveguides, mode converters from the operating mode into the TE01 mode and back again are necessary. Experimental results for the 30 GHz valves developed for the CLIC Test Facility 3 (CTF3) a...

  19. The vacuum window - a minimal concept with maximum effect

    Energy Technology Data Exchange (ETDEWEB)

    Bredsdorff, M.; Moltke, I.; Bezzel, E.

    1997-12-01

    The projects primary aim was to develop a production technology in order to produce evacuated panes at a competitive price. Insulating using vacuum is not a new concept. It has been described in patents for over a century. The field of usage of this concept is immense, and the potentials even greater. The general principle of the vacuum window is to have nothing, namely vacuum, in-between two low radiant surfaces, thus obtaining very low heat transmission technique for highly insulating evacuated windows has most certainly been reached. To obtain the mentioned vast improvements in thermal performance of the new generation of glazing there were several technical issues to be dealt with. They have been divided up into 6 tasks: Low emission glass, spacers, tempering, edge seal, evacuation and framing. The target center U-value of the vacuum window was set to be 0.7 W/m{sup 2}K, an ambitious target requiring several previously unsolved details to be solved. The center U-value of 0.7 W/m{sup 2}K has been reached and documented through this project. The production costs compares to that of existing glazing with the same insulating capabilities. (EHS) EFP-93; EFP-94; EFP-95; EFP-96; EU-BRITE-DURAM; 13 refs.

  20. Development and research of vacuum-plasma composite coatings for increase of operability of shearing dies

    Directory of Open Access Journals (Sweden)

    Volosova Marina A.

    2016-01-01

    Full Text Available The technological principles of low-temperature deposition of multilayer vacuum-plasma coatings with the increased operational properties on various types of die steels with the assistance of accelerated argon molecules beam are offered in the article. Four standard architecture of vacuum-plasma coatings - Ti/(Ti,ZrN, Cr/CrN, TiN/TiCN/(Ti,CrN and Ti/(Ti,AlN are considered. It is shown that deposition of vacuum-plasma coatings of the listed structures at the optimum modes considerably reduces intensity of wear of shearing dies therefore quality of shaped products several times increases.

  1. Entangled wavepackets in the vacuum

    Science.gov (United States)

    Kattemölle, Joris; Freivogel, Ben

    2017-10-01

    Motivated by the black hole firewall problem, we find highly entangled pairs of spatially localized modes in quantum field theory. We demonstrate that appropriately chosen wavepackets localized outside the horizon are nearly purified by `mirror' modes behind the horizon. In addition, we calculate the entanglement entropy of a single localized wavepacket in the Minkowski vacuum. In all cases we study, the quantum state of the system becomes pure in the limit that the wavepackets delocalize; we quantify the trade-off between localization and purity.

  2. Vacuum Chambers for LEP sections

    CERN Multimedia

    1983-01-01

    The picture shows sections of the LEP vacuum chambers to be installed in the dipole magnets (left) and in the quadrupoles (right). The dipole chamber has three channels: the beam chamber, the pumping duct where the NEG (non-evaporabe getter) is installed and the water channel for cooling (on top in the picture). The pumping duct is connected to the beam chamber through holes in the separating wall. The thick lead lining to shield radiation can also be seen. These chambers were manufactured as extruded aluminium alloy profiles.

  3. Laser-triggered vacuum switch

    Science.gov (United States)

    Brannon, Paul J.; Cowgill, Donald F.

    1990-01-01

    A laser-triggered vacuum switch has a material such as a alkali metal halide on the cathode electrode for thermally activated field emission of electrons and ions upon interaction with a laser beam, the material being in contact with the cathode with a surface facing the discharge gap. The material is preferably a mixture of KCl and Ti powders. The laser may either shine directly on the material, preferably through a hole in the anode, or be directed to the material over a fiber optic cable.

  4. Ultra high vacuum seal arrangement

    Science.gov (United States)

    Flaherty, Robert

    1981-01-01

    Arrangement for demountably sealing two concentric metallic tubes in an ultra high vacuum system which facilitates remote actuation. A tubular seal includes integral spaced lips which circumferentially engage the metallic tubes. The lips plastically deform the metallic tubes by mechanical forces resulting from a martensite to austenite transformation of the tubular seal upon application of a predetermined temperature. The sealing force is released upon application of another temperature which causes a transformation from the stronger austenite to the weaker martensite. Use of a dual acting sealing ring and driving ring circumferentially contacting the sealing ring is particularly applicable to sealing larger diameter concentric metallic members.

  5. Vacuum Decay via Lorentzian Wormholes

    Science.gov (United States)

    Rosales, J. L.

    We speculate about the space-time description due to the presence of Lorentzian worm-holes (handles in space-time joining two distant regions or other universes) in quantum gravity. The semiclassical rate of production of these Lorentzian wormholes in Reissner-Nordström space-times is calculated as a result of the spontaneous decay of vacuum due to a real tunneling configuration. In the magnetic case it only depends on the value of the field theoretical fine structure constant. We predict that the quantum probability corresponding to the nucleation of such geodesically complete space-times should be acutally negligible in our physical Universe.

  6. Psoriasis treatment: faster and long-standing results after bathing in geothermal seawater. A randomized trial of three UVB phototherapy regimens.

    Science.gov (United States)

    Eysteinsdóttir, Jenna Huld; Ólafsson, Jón Hjaltalín; Agnarsson, Bjarni A; Lúðvíksson, Björn Rúnar; Sigurgeirsson, Bárður

    2014-02-01

    The combination of seawater baths and narrowband ultraviolet B (NB-UVB) is a known treatment for psoriasis. This study evaluates two treatment regimens that combine bathing in geothermal seawater and NB-UVB therapy in comparison with NB-UVB monotherapy. Sixty-eight psoriasis patients were randomly assigned to outpatient bathing in geothermal seawater combined with NB-UVB therapy three times a week, intensive daily treatment involving bathing in geothermal seawater combined with NB-UVB therapy, or NB-UVB therapy alone three times a week; treatment period was 6 weeks. Disease severity [Psoriasis Area Severity Index (PASI) and Lattice System Physician's Global Assessment scores], quality of life (Dermatology Life Quality Index) and histological changes were evaluated before, during and after treatment. The primary end point was the proportion of patients who achieved PASI 75 at 6 weeks. At 6 weeks, the percentage of patients who achieved PASI 75 and PASI 90 was significantly greater for both regimens, bathing in geothermal seawater three times a week (68.1% and 18.2%, respectively) and intensive treatment with geothermal seawater (73.1% and 42.3%, respectively) than for NB-UVB monotherapy (16.7% and 0%, respectively) (P seawater combined with NB-UVB therapy in psoriasis induces faster clinical and histological improvement, produces longer remission time and permits lower NB-UVB doses than UVB therapy alone. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Robot design for a vacuum environment

    Science.gov (United States)

    Belinski, S.; Trento, W.; Imani-Shikhabadi, R.; Hackwood, S.

    1987-01-01

    The cleanliness requirements for many processing and manufacturing tasks are becoming ever stricter, resulting in a greater interest in the vacuum environment. Researchers discuss the importance of this special environment, and the development of robots which are physically and functionally suited to vacuum processing tasks. Work is in progress at the Center for robotic Systems in Microelectronics (CRSM) to provide a robot for the manufacture of a revolutionary new gyroscope in high vacuum. The need for vacuum in this and other processes is discussed as well as the requirements for a vacuum-compatible robot. Finally, researchers present details on work done at the CRSM to modify an existing clean-room compatible robot for use at high vacuum.

  8. Vacuum systems for the ILC helical undulator

    CERN Document Server

    Malyshev, O B; Clarke, J A; Bailey, I R; Dainton, J B; Malysheva, L I; Barber, D P; Cooke, P; Baynham, E; Bradshaw, T; Brummitt, A; Carr, S; Ivanyushenkov, Y; Rochford, J; Moortgat-Pick, G A

    2007-01-01

    The International Linear Collider (ILC) positron source uses a helical undulator to generate polarized photons of ∼10MeV∼10MeV at the first harmonic. Unlike many undulators used in synchrotron radiation sources, the ILC helical undulator vacuum chamber will be bombarded by photons, generated by the undulator, with energies mostly below that of the first harmonic. Achieving the vacuum specification of ∼100nTorr∼100nTorr in a narrow chamber of 4–6mm4–6mm inner diameter, with a long length of 100–200m100–200m, makes the design of the vacuum system challenging. This article describes the vacuum specifications and calculations of the flux and energy of photons irradiating the undulator vacuum chamber and considers possible vacuum system design solutions for two cases: cryogenic and room temperature.

  9. STG-CT: High-vacuum plume test facility for chemical thrusters

    Directory of Open Access Journals (Sweden)

    Martin Grabe

    2016-08-01

    Full Text Available The STG-CT, operated by the DLR Institute for Aerodynamics and Flow Technology in Göttingen, is a vacuum facility specically designed to provide and maintain a space-like vacuum environment for researching plume flow and plume impingement from satellite reaction control thrusters. Its unique liquid-helium driven cryopump of 30m2 allows maintaining a background pressure <10^-5 mbar even when molecular hydrogen is a plume constituent.

  10. Vacuum treatments for hydrogen removal in 140 ton ladle for big ingots casting

    OpenAIRE

    Paura, M.; De Santis, M.; Calderini, M.; Neri, S.; Palomba, R.; Sartini, L.

    2010-01-01

    Hydrogen removal can be accomplished via different steelmaking routes (VOD, ASEA, RH). Focus was givenon the first two technologies. As main differences between the systems based on a (multi)-plug equipped ladle,in VOD the vacuum chamber is obtained by coupling a roof with a tank, in ASEA plant–where electromagnetic melt stirring is also exploited - coupling occurs directly with the ladle, leading oftento a non perfect sealing. Moreover, VOD plant is able to perform under vacuum steel degassi...

  11. Advanced Photon Source accelerator ultrahigh vacuum guide

    International Nuclear Information System (INIS)

    Liu, C.; Noonan, J.

    1994-03-01

    In this document the authors summarize the following: (1) an overview of basic concepts of ultrahigh vacuum needed for the APS project, (2) a description of vacuum design and calculations for major parts of APS, including linac, linac waveguide, low energy undulator test line, positron accumulator ring (PAR), booster synchrotron ring, storage ring, and insertion devices, and (3) cleaning procedures of ultrahigh vacuum (UHV) components presently used at APS

  12. Ceramic vacuum tubes for geothermal well logging

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, R.D.

    1977-01-01

    Useful design data acquired in the evaluation of ceramic vacuum tubes for the development of a 500/sup 0/C instrumentation amplifier are presented. The general requirements for ceramic vacuum tubes are discussed for application to the development of high temperature well logs. Commercially available tubes are described and future contract activities that specifically relate to ceramic vacuum tubes are detailed. Supplemental data are presented in the appendix.

  13. High-vacuum plasma pump

    International Nuclear Information System (INIS)

    Dorodnov, A.M.; Minajchev, V.E.; Miroshkin, S.I.

    1980-01-01

    The action of an electric-arc high-vacuum pump intended for evacuating the volumes in which the operation processes are followed by a high gas evolution is considered. The operation of the pump is based on the principle of controlling the getter feed according to the gas load and effect of plasma sorbtion pumping. The pump performances are given. The starting pressure is about 5 Pa, the limiting residual pressure is about 5x10 -6 Pa, the pumping out rate of nitrogen in the pressure range 5x10 -5 -5x10 -3 Pa accounts for about 4000 l/s, the power consumption comes to 6 kW. Analyzing the results of the test operation of the pump, it has been concluded that its principal advantages are the high starting pressure, controlled getter feed rate and possibility of pumping out the gases which are usually pumped out with difficulty. The operation reliability of the pump is defined mainly by reliable operation of the ignition system of the vacuum arc [ru

  14. Vacuum Attachment for XRF Scanner

    Science.gov (United States)

    Schramm, Harry F.; Kaiser, Bruce

    2005-01-01

    Vacuum apparatuses have been developed for increasing the range of elements that can be identified by use of x-ray fluorescent (XRF) scanners of the type mentioned in the two immediately preceding articles. As a consequence of the underlying physical principles, in the presence of air, such an XRF scanner is limited to analysis of chlorine and elements of greater atomic number. When the XRF scanner is operated in a vacuum, it extends the range of analysis to lower atomic numbers - even as far as aluminum and sodium. Hence, more elements will be available for use in XRF labeling of objects as discussed in the two preceding articles. The added benefits of the extended capabilities also have other uses for NASA. Detection of elements of low atomic number is of high interest to the aerospace community. High-strength aluminum alloys will be easily analyzed for composition. Silicon, a major contaminant in certain processes, will be detectable before the process is begun, possibly eliminating weld or adhesion problems. Exotic alloys will be evaluated for composition prior to being placed in service where lives depend on them. And in the less glamorous applications, such as bolts and fasteners, substandard products and counterfeit items will be evaluated at the receiving function and never allowed to enter the operation

  15. Gases vacuum dedusting and cooling

    Directory of Open Access Journals (Sweden)

    Alexey А. Burov

    2015-03-01

    Full Text Available Represented are the results of operating the ladle degassing vacuum plant (productivity: 120 tons of liquid steel with various dust collectors. The process gases’ cooling and dedusting, obtained in the closed loop buran study, provides opportunity to install a bag filter after that closed loop and its efficient use. Proven is the effectiveness of the cylindrical cyclone replacement with a multichannel (buran dust collector, based on a system of closed-loop (return coupling serially connected curved ducts, where the dusty gas flow rotation axis is vertically positioned. The system of closed-loop serially connected curvilinear channels creates preconditions for the emergence of a negative feedback at the curvilinear gas flow containing transit and circulating flows. These conditions are embodied with circulating flows connecting the in- and outputs of the whole system each channel. The transit flow multiple continuous filtration through the circulating dust layers leads to the formation and accumulation of particles aggregates in the collection chamber. The validity of such a dusty flow control mechanism is confirmed by experimental data obtained in a vacuum chamber. Therefore, replacing one of the two buran’s forevacuum pumps assemblies with the necessary number of curved channels (closed loop is estimated in a promising method.

  16. UVB pretreatment of rat bone marrow allografts. Prevention of GVHD and induction of allochimerism and donor-specific unresponsiveness

    International Nuclear Information System (INIS)

    Chabot, J.A.; Pepino, P.; Wasfie, T.; Stegall, M.D.; Marboe, C.; Hardy, M.A.

    1990-01-01

    Ultraviolet B irradiation has been used to pretreat blood and islets to prevent subsequent graft rejection. In this study the optimal dose of UVB irradiation of bone marrow was determined in syngeneic recipients and was subsequently applied to in-vitro treatment of bone marrow allografts. UVB pretreatment of donor bone marrow inoculum led to complete prevention of GVHD in allogeneic rat recipients without major marrow or other toxicity. Long-standing recipients of allogeneic UVB-BM became stable adult chimeras. The recipients of allogeneic BM were populated by donor-type peripheral blood lymphocytes and did not reject host or donor-type heart grafts. The BM allograft recipients were immunocompetent as measured by their ability to normally reject third-party cardiac allografts. We suggest that the prevention of GVHD and induction of stable chimerism in adult recipients of allogeneic UVB-BM may be mediated by suppressor mechanisms

  17. Effects of UV-B radiation on the isoflavone accumulation and physiological-biochemical changes of soybean during germination: Physiological-biochemical change of germinated soybean induced by UV-B.

    Science.gov (United States)

    Ma, Meng; Wang, Pei; Yang, Runqiang; Gu, Zhenxin

    2018-06-01

    In this study, the effects of UV-B radiation on the isoflavones accumulation, physiological and nutritional quality, water status, and characteristics of proteins in germinated soybeans were investigated. The results showed that isoflavones content in soybeans increased with appropriate intensity and time of UV-B radiation and decreased with excessive treatment. Fresh weight, length, free amino acids, reducing sugar contents and bulk water (T 23 ) in germinated soybeans decreased with increasing radiation time, indicating that UV-B inhibited the growth and nutrients metabolism of soybean during germination. Cell damage was detected in germinated soybeans with excessive UV-B radiation, as shown by the black spots in cotyledons and the increased intercellular water determined by LF-NMR. Germination resulted in an increase in random coil structures, while UV-B radiation induced no obvious changes in FT-IR spectrum and protein conformation of soybeans. Both UV-B radiation and germination caused the increase in soluble proteins, especially in 1.0-75.0 kDa fraction. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Vacuum Compatible Percussive Dynamic Cone Penetrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Honeybee Robotics proposes to develop a vacuum compatible percussive dynamic cone penetrometer (PDCP), for establishing soil bin characteristics, with the ultimate...

  19. Cold vacuum drying facility design requirements

    International Nuclear Information System (INIS)

    IRWIN, J.J.

    1999-01-01

    This document provides the detailed design requirements for the Spent Nuclear Fuel Project Cold Vacuum Drying Facility. Process, safety, and quality assurance requirements and interfaces are specified

  20. APS Storage Ring vacuum chamber fabrication

    International Nuclear Information System (INIS)

    Goeppner, G.A.

    1990-01-01

    The 1104-m circumference Advanced Photon Source Storage Ring Vacuum System is composed of 240 individual sections, which are fabricated from a combination of aluminum extrusions and machined components. The vacuum chambers will have 3800 weld joints, each subject to strict vacuum requirements, as well as a variety of related design criteria. The vacuum criteria and chamber design are reviewed, including a discussion of the weld joint geometries. The critical fabrication process parameters for meeting the design requirements are discussed. The experiences of the prototype chamber fabrication program are presented. Finally, the required facilities preparation for construction activity is briefly described. 6 refs., 6 figs., 1 tab